Updated on 2022/07/04

写真a

 
ASAHI, Toru
 
Affiliation
Faculty of Science and Engineering, School of Advanced Science and Engineering
Job title
Professor

Concurrent Post

  • Faculty of International Research and Education   School of International Liberal Studies

  • Faculty of Science and Engineering   Graduate School of Advanced Science and Engineering

  • Affiliated organization   Global Education Center

Research Institute

  • 2021
    -
    2022

    データ科学センター   兼任センター員

  • 2020
    -
    2022

    理工学術院総合研究所   兼任研究員

  • 2019
    -
    2023

    グローバル科学知融合研究所   プロジェクト研究所所長

Education

  •  
    -
    1991

    Waseda University   Graduate School, Division of Science and Engineering  

  •  
    -
    1991

    Waseda University   Graduate School, Division of Science and Engineering  

  •  
    -
    1986

    Waseda University   Faculty of Science and Engineering  

Degree

  • Waseda University   Doctor of Science

  • Waseda University   Master of Business Administration (MBA)

Research Experience

  • 2007
    -
     

    同大学理工学術院先進理工学部 生命医科学科 教授

  • 2004
    -
     

    同大学先端科学・健康医療融合研究機構 生命医療工学インスティテュート 教授

  • 2003
    -
     

    同大学大学院理工学研究科ナノ理工学専攻 客員助教授

  • 2002
    -
     

    同大学理工学総合研究センター 客員助教授

  • 1997
    -
     

    同研究所 客員助教授

  • 1995
    -
     

    Waseda University   Kagami Memorial Research Institute for Materials Science and Technology

  • 1993
    -
     

    日本学術振興会 博士特別研究員

  • 1993
    -
     

    日本学術振興会 博士特別研究員

  • 1992
    -
     

    同大学 博士(理学)

  • 1990
    -
     

    Waseda University   School of Science and Engineering

  • 1990
    -
     

    Waseda University   School of Science and Engineering

  • 1988
    -
     

    同理工学研究科物理学及び応用物理学専攻修士課程修了

  • 1986
    -
     

    Waseda University   School of Science and Engineering

  •  
     
     

    経営学修士(専門職)

▼display all

Professional Memberships

  •  
     
     

    The Pharmaceutical Society of Japan

  •  
     
     

    The Electrochemical Society of Japan

  •  
     
     

    The Ceramic Society of Japan

  •  
     
     

    The Magnetics Society of Japan

  •  
     
     

    The Crystallographic Society of Japan

  •  
     
     

    The Chemical Society of Japan

  •  
     
     

    The Physical Society of Japan

  •  
     
     

    The Japan Society of Applied Physics

  •  
     
     

    The Society of Polymer Science, Japan

▼display all

 

Research Interests

  • Bio-Solid State Science / Chiral Science / Magnetic thin film

Research Seeds

Papers

  • The Neuroprotective Effect of Thalidomide against Ischemia through the Cereblon-mediated Repression of AMPK Activity

    Naoya Sawamura, Mariko Yamada, Miku Fujiwara, Haruka Yamada, Hideki Hayashi, Norio Takagi, Toru Asahi

    Scientific Reports   8 ( 1 )  2018.12

     View Summary

    Thalidomide was originally used as a sedative and found to be a teratogen, but now thalidomide and its derivatives are widely used to treat haematologic malignancies. Accumulated evidence suggests that thalidomide suppresses nerve cell death in neurologic model mice. However, detailed molecular mechanisms are unknown. Here we examined the molecular mechanism of thalidomide's neuroprotective effects, focusing on its target protein, cereblon (CRBN), and its binding protein, AMP-activated protein kinase (AMPK), which plays an important role in maintaining intracellular energy homeostasis in the brain. We used a cerebral ischemia rat model of middle cerebral artery occlusion/reperfusion (MCAO/R). Thalidomide treatment significantly decreased the infarct volume and neurological deficits of MCAO/R rats. AMPK was the key signalling protein in this mechanism. Furthermore, we considered that the AMPK-CRBN interaction was altered when neuroprotective action by thalidomide occurred in cells under ischemic conditions. Binding was strong between AMPK and CRBN in normal SH-SY5Y cells, but was weakened by the addition of H2O2. However, when thalidomide was administered at the same time as H2O2, the binding of AMPK and CRBN was partly restored. These results suggest that thalidomide inhibits the activity of AMPK via CRBN under oxidative stress and suppresses nerve cell death.

    DOI

  • Consolidation of Sm2Fe17N3 magnets with Sm-based eutectic alloy binder

    Kohei Otogawa, Kenta Takagi, Toru Asahi

    Journal of Alloys and Compounds   746   19 - 26  2018.05

     View Summary

    Consolidation of Sm2Fe17N3 powder with a new Sm-based alloy as a metal binder was examined. Investigation of various Sm-based alloys led to the discovery of a Sm-Fe-Cu-Al alloy having a low melting point of 495 °C, which is more than 100 °C lower than the thermal decomposition temperature of Sm2Fe17N3. The metallographic structure of the Sm-Fe-Cu-Al alloy ingot was a SmCu/Sm eutectic structure containing solid-solution Fe, Cu and Al. Pulverized Sm-Fe-Cu-Al powder as a binder was mixed with Sm2Fe17N3 powder, and the mixture was hot-pressed by a current sintering apparatus. The Sm-Fe-Cu-Al alloy binder did not affect the magnetization of Sm2Fe17N3 adversely after consolidation. The binder-added Sm2Fe17N3 hot-pressed compacts successfully maintained the coercivity of the raw powder over a wide range of hot-pressing temperatures, whereas additive-free Sm2Fe17N3 hot-pressed compacts showed a significant decrease in coercivity. Therefore, the Sm-Fe-Cu-Al alloy binder overcame the weakest point of Sm2Fe17N3 magnets. XRD analysis suggested that the Sm-Fe-Cu-Al binder restrained precipitation of the α-Fe phase, which is thought to be the probable cause the decrease of coercivity.

    DOI

  • A dual-ligand-modulable fluorescent protein based on UnaG and calmodulin

    Yoh Shitashima, Togo Shimozawa, Toru Asahi, Atsushi Miyawaki

    Biochemical and Biophysical Research Communications   496 ( 3 ) 872 - 879  2018.02

     View Summary

    UnaG is a green-emitting fluorescent protein that utilizes unconjugated bilirubin (BR) as its fluorophore. While BR has captured the attention of physiologists as an important antioxidant that scavenges reactive oxygen species in biological membranes, its excessive accumulation causes several clinical symptoms. Although the optimal regulation of BR concentration would result in clinical therapies for aging as well as reduce risks of clinical symptoms, UnaG hardly releases BR owing to its extremely high affinity for BR (Kd = 98 pM). Herein, we engineered the BR binding and fluorescence of UnaG to be Ca2+-sensitive via a genetic insertion of calmodulin (CaM). The resultant UnaG/CaM hybrid protein is a dual-ligand modulable fluorescent protein
    binding of the fluorogenic ligand BR is negatively regulated by the other ligand, Ca2+ ion. The affinity for BR differed by three orders of magnitude between the Ca2+-free state (Kd = 9.70 nM) and Ca2+-saturated state (Kd = 9.65 μM). The chimeric protein can release nano- to micro-molar levels of BR with Ca2+ control, and is thus named BReleaCa (BR + releaser + Ca2+). Such a protein hybridization technique will be generally applicable to change the ligand binding properties of a variety of ligand-inducible functional proteins.

    DOI PubMed

  • Walking and rolling of crystals induced thermally by phase transition

    Takuya Taniguchi, Haruki Sugiyama, Hidehiro Uekusa, Motoo Shiro, Toru Asahi, Hideko Koshima

    NATURE COMMUNICATIONS   9 ( 1 )  2018.02

     View Summary

    The mechanical motion of materials has been increasingly explored in terms of bending and expansion/contraction. However, the locomotion of materials has been limited. Here, we report walking and rolling locomotion of chiral azobenzene crystals, induced thermally by a reversible single-crystal-to-single-crystal phase transition. Long plate-like crystals with thickness gradient in the longitudinal direction walk slowly, like an inchworm, by repeated bending and straightening under heating and cooling cycles near the transition temperature. Furthermore, thinner, longer plate-like crystals with width gradient roll much faster by tilted bending and then flipping under only one process of heating or cooling. The length of the crystal is shortened above the transition temperature, which induces bending due to the temperature gradient to the thickness direction. The bending motion is necessarily converted to the walking and rolling locomotion due to the unsymmetrical shape of the crystal. This finding of the crystal locomotion can lead to a field of crystal robotics.

    DOI

  • Two Distinct Fluorescence States of the Ligand-Induced Green Fluorescent Protein UnaG

    Yoh Shitashima, Togo Shimozawa, Akiko Kumagai, Atsushi Miyawaki, Toru Asahi

    BIOPHYSICAL JOURNAL   113 ( 12 ) 2805 - 2814  2017.12  [Refereed]

     View Summary

    UnaG is a recently discovered ligand-induced fluorescent protein that utilizes bound bilirubin (BR) as its fluorophore. The fluorescence of the UnaG-BR complex (holoUnaG) compares in quantum efficiency to that of enhanced green fluorescent protein, but it is superior in that the fluorophore formation is instantaneous and not dependent on oxygen; hence, much attention has been paid to UnaG as a new fluorescent probe. However, many important molecular properties of fluorescent probes remain unknown, such as the association/dissociation rates of BR, which determine the stability thereof, and the dispersibility of UnaG in aqueous solutions, which influence the functions of labeled proteins. In this study, we found, in the process of investigating the association rate, that the holoUnaG takes two distinct fluorescence states, which we named holoUnaG(1) and holoUnaG(2). The holoUnaG(1) initially forms after binding BR and then changes to the brighter holoUnaG(2) by a reversible intra-molecular reaction, thereby finally reaching an equilibrium between the two states. Spectroscopic analysis indicated that the intra-molecular reaction was associated not with a chemical change of BR but with a change in the environmental conditions surrounding BR. We also revealed that the molecular brightness ratio and equilibrium population ratio of the two states (holoUnaG(1)/holoUnaG(2)) were 1:3.9 and 6:4, respectively, using photon number counting analysis. From these results, we have suggested a novel schema, to our knowledge, for the formation of the UnaG and BR complex system and have determined the various rate constants associated therein. Additionally, using analytical ultracentrifugation, we established that UnaG in the apo-state (apoUnaG) and the holoUnaG are monomeric in aqueous solution. These findings provide not only key information for the practical use of UnaG as a fluorescent probe, but also the possibility for development of a brighter UnaG mutant by genetic engineering to constitutive holoUnaG(2).

    DOI PubMed

  • Optical Activity Anisotropy of Benzil

    Kenta Nakagawa, Alexander T. Martin, Shane M. Nichols, Veronica L. Murphy, Bart Kahr, Toru Asahi

    JOURNAL OF PHYSICAL CHEMISTRY C   121 ( 45 ) 25494 - 25502  2017.11  [Refereed]

     View Summary

    Optical activity (OA) along the optic axis of crystalline benzil has been measured by many over the past 150 years. However, the OA anisotropy remains uncharacterized due to difficulties in sample preparation as well as competition with linear birefringence (LB). The challenges associated with measuring OA along low-symmetry directions in crystals have too often left scientists with only average values of nonresonant OA in solution, i.e., specific rotations, which continue to resist interpretation in terms of structure. Measuring OA anisotropy has been facilitated by recent advances in polarimetry and optical modeling and here we compare results from two distinct division-of-time polarimeters. The absolute structure of crystalline benzil was established for the first time. The optical rotation (OR) of (+)-crystalline benzil (space group P3(1)21) perpendicular to the optic axis at the sodium D-line is -24.6 +/- 1.1 degrees/mm. A spectroscopic optical model in the transparent region of the crystal is provided. Electronic structure calculations of OR inform the polarimetric measurements and point to the necessity of developing linear response theory with periodic boundary conditions in order to interpret the results of chiroptical measurements in crystals.

    DOI

  • Block-Copolymer-Assisted Electrochemical Synthesis of Mesoporous Gold Electrodes: Towards a Non-Enzymatic Glucose Sensor

    Asep Sugih Nugraha, Cuiling Li, Jiang Bo, Muhammad Iqbal, Saad M. Alshehri, Tansir Ahamad, Victor Malgras, Yusuke Yamauchi, Toru Asahi

    CHEMELECTROCHEM   4 ( 10 ) 2571 - 2576  2017.10  [Refereed]

     View Summary

    Sensing technology for biomolecules has played a key role for maintaining a high quality of life. Various kinds of sensing techniques have been developed for detecting biomolecules. Among the detection techniques which have been reported so far, non-enzymatic glucose detection, based on electrochemical mechanisms, has attracted great interest as a facile route for monitoring glucose levels in the blood. In this method, designing nanostructured electrodes is a promising strategy to improve detection performance. Owing to their fascinating physicochemical properties, including superior electrical and electrocatalytic properties, mesoporous metal films offer a wide range of useful applications which cannot be achieved by other mesoporous materials. In this work, mesoporous Au films (MpGFs) are synthesized by an effective and simple electrochemical process in the presence of a surfactant, where the mesoporous structure can be controlled by the size of the polymeric micelles. The micelles are removed using a tetrahydrofuran-based solvent-extraction method. The activity of MpGFs towards glucose oxidation is evaluated under a fixed potential in alkaline solution. Under optimal potentials, the current response for other interfering molecules is minimal, while the current response for glucose is maximal. A linear relationship between the current response and the glucose content is observed over a wide range of concentrations. Thus, our MpGF shows an excellent performance for electrochemical glucose sensing applications.

    DOI

  • Fabrication of Mesoporous Cu Films on Cu Foils and Their Applications to Dopamine Sensing

    Daisuke Baba, Cuiling Li, Victor Malgras, Bo Jiang, Hatem R. Alamri, Zeid A. Alothman, Md. Shahriar A. Hossain, Yusuke Yamauchi, Toru Asahi

    CHEMISTRY-AN ASIAN JOURNAL   12 ( 18 ) 2467 - 2470  2017.09  [Refereed]

     View Summary

    We previously succeeded to prepare stable mesoporous Cu films on Au-coated conductive working electrodes by using polystyrene-b-poly(oxyethylene) (PS63000-b-PEO26000) micelles as template and sulfuric acid to increase ionic conductivity. In the present study, we report the preparation of mesoporous Cu films on Cu foil. By changing the Cu salts and electrodeposition potentials, we discuss how these parameters influence the final product. Without having to filtrate interefering species, such as uric acid, ascorbic acid and glucose, the dopamine concentration can be precisely determined by applying a suitable potential. Therefore, non-invasive electrochemical sensing based on mesoporous films will be useful for daily diagnosis of mental disorder.

    DOI PubMed

  • Continuous Mesoporous Pd Films by Electrochemical Deposition in Nonionic Micellar Solution

    Muhammad Iqbal, Cuiling Li, Kathleen Wood, Bo Jiang, Toshiaki Takei, Omer Dag, Daisuke Baba, Asep Sugih Nugraha, Toru Asahi, Andrew E. Whitten, Md. Shahriar A. Hossain, Victor Malgras, Yusuke Yamauchi

    CHEMISTRY OF MATERIALS   29 ( 15 ) 6405 - 6413  2017.08  [Refereed]

     View Summary

    Mesoporous metals that combine catalytic activity and high surface area can provide more opportunities for electrochemical applications. Various synthetic methods, including hard and soft templating, have been developed to prepare mesoporous/nanoporous metals. Micelle assembly, typically involved in soft-templates, is flexible and convenient for such purposes. It is, however, difficult to control, and the ordering is significantly destroyed during the metal deposition process, which is detrimental when it comes to designing precisely mesostructured materials. In the present work, mesoporous Pd films were uniformly electrodeposited using a nonionic surfactant, triblock copolymer poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide), as a pore-directing agent. The interaction between micelles and metal precursors greatly influences the metal growth and determines the final structure. The water-coordinated species interact with the ethylene oxide moiety of the micelles to effectively drive the Pd(II) species toward the working electrode surface. From small-angle neutron scattering data, it is found that spherical P123 micelles, with an average diameter of similar to 14 nm, are formed in the electrolyte, and the addition of Pd ions does not significantly modify their structure, which is the essence of the micelle assembly approach. The uniformly sized mesopores are formed over the entire mesoporous Pd film and have an average pore diameter of 10.9 nm. Cross-sectional observation of the film also shows mesopores spanning continuously from the bottom to the top of the film. The crystallinity, crystal phase, and electronic coordination state of the Pd film are also confirmed. Through this study, it is found that the optimized surfactant concentration and applied deposition potential are the key factors to govern the formation of homogeneous and well-distributed pores over the entire film. Interestingly, the as-prepared mesoporous Pd films exhibit superior electrocatalytic activity toward the ethanol oxidation reaction by fully utilising the accessible active surface area. Our approach combines electrochemistry with colloidal and coordination chemistry and is widely applicable to other promising metals and alloy electrocatalysts.

    DOI

  • Chiral Sensing with Mesoporous Pd@Pt Nanoparticles

    Yuxi Fang, Cuiling Li, Jiang Bo, Joel Henzie, Yusuke Yamauchi, Toru Asahi

    CHEMELECTROCHEM   4 ( 8 ) 1832 - 1835  2017.08  [Refereed]

     View Summary

    Mesoporous Pd@Pt nanoparticles possess high surface areas while still maintaining electroconductivity and low potential for agglomeration. By introducing L-or D-DOPA (3,4-dihydroxyphe-nylalanine) enantiomers during the synthesis of the mesoporous Pd@Pt nanoparticles, we can create a Pt shell that is sensitive to the chirality of the DOPA molecule. We demonstrate sensitive electrochemical detection of DOPA enantiomers.

    DOI

  • LC-MS/MS and chiroptical spectroscopic analyses of multidimensional metabolic systems of chiral thalidomide and its derivatives

    Yoshiyuki Ogino, Masahito Tanaka, Togo Shimozawa, Toru Asahi

    CHIRALITY   29 ( 6 ) 282 - 293  2017.06  [Refereed]

     View Summary

    Enantiomeric thalidomide undergoes various kinds of biotransformations including chiral inversion, hydrolysis, and enzymatic oxidation, which results in several metabolites, thereby adding to the complexity in the understanding of the nature of thalidomide. To decipher this complexity, we analyzed the multidimensional metabolic reaction networks of thalidomide and related molecules in vitro. Characteristic patterns in the amount of various metabolites of thalidomide and related molecules generated during a combination of chiral inversion, hydrolysis, and hydroxylation were observed using liquid chromatography-tandem mass spectrometry and chiroptical spectroscopy. We found that monosubstituted thalidomide derivatives exhibited different time-dependent metabolic patterns compared with thalidomide. We also revealed that monohydrolyzed and monohydroxylated metabolites of thalidomide were likely to generate mainly by a C-5 oxidation of thalidomide and subsequent ring opening of the hydroxylated metabolite. Since chirality was conserved in most of these metabolites during metabolism, they had the same chirality as that of nonmetabolized thalidomide. Our findings will contribute toward understanding the significant pharmacological effects of the multiple metabolites of thalidomide and its derivatives.

    DOI

  • Accurate measurement of the optical activity of alanine crystals and the determination of their absolute chirality

    Kazuhiko Ishikawa, Yukana Terasawa, Masahito Tanaka, Toru Asahi

    JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS   104   257 - 266  2017.05  [Refereed]

     View Summary

    Wavelength dependence measurements of the chiroptical properties in alanine crystals have so far been unsuccessful using conventional spectroscopic techniques. We describe our attempts to measure the wavelength dependence of the optical activity in L- and D-alanine crystals along each crystallographic axis, and to determine the absolute chirality of alanine crystals by correlating the absolute structure to the optical activity using an x-ray diffractometer and a generalized high accuracy universal polarimeter. We have succeeded in accurately measuring the optical rotatory dispersion in the < 010 > direction, which shows that the optical rotation of the n-alanine crystal is dextrorotatory and that of the L-alanine crystal is laevorotatory, thereby determining the absolute chirality. Furthermore, comparison with the optical activity in solution shows that the optical activity in alanine crystals is different not only in value, but also in the sign. These results have led us to conclude that the optical rotatory power in the crystalline state should not be simply the summation of molecular optical rotatory power values. We propose the necessity of a theory, which contains the contribution of molecular interactions within the crystal, in order to calculate the optical rotatory power of the crystalline state.

    DOI

  • Fast-type high-accuracy universal polarimeter using charge-coupled device spectrometer

    Akifumi Takanabe, Hideko Koshima, Toru Asahi

    AIP ADVANCES   7 ( 2 )  2017.02  [Refereed]

     View Summary

    A fast, high-accuracy universal polarimeter was developed using a charge-coupled device (CCD) spectrometer (CCD-HAUP), to carry out simultaneous optical anisotropic (linear birefringence, LB; linear dichroism, LD) and chiroptical (circular birefringence, CB; circular dichroism, CD) measurements on single crystals without any pretreatment, in the visible region between 400-680 nm. The principle of the HAUP method is to measure the intensities of emergent light passing through a polarizer, a crystal sample, and then an analyzer, as the azimuth angles of the polarizer and analyzer are independently altered. The CCD-HAUP has the unique feature that white transmitted light intensity can be measured using a CCD spectrometer, compared with the generalized HAUP (G-HAUP) system in which monochromatic transmitted light is measured using a photomultiplier. The CCD-HAUP measurements across the entire wavelength region are completed within the G-HAUP measurement time for a single wavelength. The CCD-HAUP drastically reduces the measurement time for a dataset to only 1.5 h, from the 24 h required for the G-HAUP system. LB, LD, CB, and CD measurements of single crystals of alpha-quartz and enantiomeric photomechanical sali-cylidenephenylethylamines before, during, and after ultraviolet light irradiation show results comparable to those obtained using the G-HAUP system. The newly developed system is very effective for samples susceptible to degradation induced by external stimuli, such as light and heat. (C) 2017 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license.

    DOI

  • Reversible Single-Crystal-to-Single-Crystal Phase Transition of Chiral Salicylidenephenylethylamine

    Akifumi Takanabe, Takuro Katsufuji, Kohei Johmoto, Hidehiro Uekusa, Motoo Shiro, Hideko Koshima, Toru Asahi

    CRYSTALS   7 ( 1 )  2017.01  [Refereed]

     View Summary

    The chiral crystal of enantiomeric (S)-N-3,5-di-tert-butylsalicylidene-1-phenylethylamine in the enol form [enol-(S)-1] undergoes a reversible single-crystal-to-single-crystal (SCSC) phase transition at T-c approximate to 3 degrees C from the room temperature beta-form in orthorhombic space group P2(1)2(1)2(1) (Z' = 1) to the low temperature -form in the monoclinic space group P2(1) (Z' = 2) with a thermal hysteresis of approximately 1.7 degrees C. A detailed comparison of the crystal structures of the alpha- and beta-forms revealed that the 5-tert-butyl group of one molecule in the asymmetric unit of the beta-form rotated by ca. 60 degrees, and the dihedral angle between the phenyl and salicyl planes increased slightly in the beta-form crystal. However, the changes in the molecular conformation and packing arrangement are small, which leads to the reversible SCSC phase transition with no destruction of the crystal lattice. The dielectric constant along the b-axis was small, probably due to the weak intermolecular interactions in the crystals.

    DOI

  • Ohgata, the Single Drosophila Ortholog of Human Cereblon, Regulates Insulin Signaling-dependent Organismic Growth

    Satoru Wakabayashi, Naoya Sawamura, Andre Voelzmann, Meike Broemer, Toru Asahi, Michael Hoch

    JOURNAL OF BIOLOGICAL CHEMISTRY   291 ( 48 ) 25120 - 25132  2016.11  [Refereed]

     View Summary

    Cereblon (CRBN) is a substrate receptor of the E3 ubiquitin ligase complex that is highly conserved in animals and plants. CRBN proteins have been implicated in various biological processes such as development, metabolism, learning, and memory formation, and their impairment has been linked to autosomal recessive non-syndromic intellectual disability and cancer. Furthermore, human CRBN was identified as the primary target of thalidomide teratogenicity. Data on functional analysis of CRBN family members in vivo, however, are still scarce. Here we identify Ohgata (OHGT), the Drosophila ortholog of CRBN, as a regulator of insulin signaling-mediated growth. Using ohgt mutants that we generated by targeted mutagenesis, we show that its loss results in increased body weight and organ size without changes of the body proportions. We demonstrate that ohgt knockdown in the fat body, an organ analogous to mammalian liver and adipose tissue, phenocopies the growth phenotypes. We further show that overgrowth is due to an elevation of insulin signaling in ohgt mutants and to the down-regulation of inhibitory cofactors of circulating Drosophila insulin-like peptides (DILPs), named acid-labile subunit and imaginal morphogenesis protein-late 2. The two inhibitory proteins were previously shown to be components of a heterotrimeric complex with growth-promoting DILP2 and DILP5. Our study reveals OHGT as a novel regulator of insulin-dependent organismic growth in Drosophila.

    DOI

  • Optical Activity and Optical Anisotropy in Photomechanical Crystals of Chiral Salicylidenephenylethylamines

    Akifumi Takanabe, Masahito Tanaka, Kohei Johmoto, Hidehiro Uekusa, Tadashi Mori, Hideko Koshima, Toru Asahi

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   138 ( 45 ) 15066 - 15077  2016.11  [Refereed]

     View Summary

    Introducing chirality into photomechanical crystals is beneficial for the diversification of mechanical motion. Measurement of the chiroptical and optical anisotropic properties of chiral crystals is indispensable for evaluating photomechanical crystals. The platelike crystals of S- and R-enantiomers of photochromic N-3,5-di-tert-butylsalicylidene-1-phenylethylamine in enol form (enol-(S)-1 and enol-(R)-1) caused bending motion with twisting upon ultraviolet (UV) light irradiation, due to shrinkage along the length and width directions of the irradiated surface, based on the optimized crystal structure of the photoisomerized trans-keto-(S)-1. By employing the generalized high-accuracy universal polarimeter (G-HAUP), optical anisotropic (linear birefringence, LB; linear dichroism, LD) as well as chiroptical (circular birefringence, CB; circular dichroism, CD) spectra of both the enantiomeric crystals on the (001) face were simultaneously measured before and under continuous UV irradiation. The LD peak was observed at 330 nm in the negative sign, derived from the pi-pi* transition of the intramolecularly hydrogen-bonded salicylidenimino moiety. The CD spectra of the S and R crystals revealed the negative and positive Cotton effect at 330 nm, respectively, and new peaks appeared at 460 rim under UV light irradiation due to photoisomerization to the S and R trans-keto isomers at around 10% conversion. The CB and CD spectra evaluated by the HAUP measurement were opposite to those measured in the hexane solution, as well as those simulated by quantum chemical calculation. The dissymmetry parameter, g, of the enol-(S)-1 crystal along the c axis (0.013) was approximately 10 times larger than the g values in the solution (0.0010) and by calculation (0.0016).

    DOI

  • Ohgata, the Single Drosophila Ortholog of Human Cereblon, Regulates Insulin Signaling-dependent Organismic Growth

    Satoru Wakabayashi, Naoya Sawamura, Andre Voelzmann, Meike Broemer, Toru Asahi, Michael Hoch

    JOURNAL OF BIOLOGICAL CHEMISTRY   291 ( 48 ) 25120 - 25132  2016.11  [Refereed]

     View Summary

    Cereblon (CRBN) is a substrate receptor of the E3 ubiquitin ligase complex that is highly conserved in animals and plants. CRBN proteins have been implicated in various biological processes such as development, metabolism, learning, and memory formation, and their impairment has been linked to autosomal recessive non-syndromic intellectual disability and cancer. Furthermore, human CRBN was identified as the primary target of thalidomide teratogenicity. Data on functional analysis of CRBN family members in vivo, however, are still scarce. Here we identify Ohgata (OHGT), the Drosophila ortholog of CRBN, as a regulator of insulin signaling-mediated growth. Using ohgt mutants that we generated by targeted mutagenesis, we show that its loss results in increased body weight and organ size without changes of the body proportions. We demonstrate that ohgt knockdown in the fat body, an organ analogous to mammalian liver and adipose tissue, phenocopies the growth phenotypes. We further show that overgrowth is due to an elevation of insulin signaling in ohgt mutants and to the down-regulation of inhibitory cofactors of circulating Drosophila insulin-like peptides (DILPs), named acid-labile subunit and imaginal morphogenesis protein-late 2. The two inhibitory proteins were previously shown to be components of a heterotrimeric complex with growth-promoting DILP2 and DILP5. Our study reveals OHGT as a novel regulator of insulin-dependent organismic growth in Drosophila.

    DOI PubMed

  • Optical Activity and Optical Anisotropy in Photomechanical Crystals of Chiral Salicylidenephenylethylamines

    Akifumi Takanabe, Masahito Tanaka, Kohei Johmoto, Hidehiro Uekusa, Tadashi Mori, Hideko Koshima, Toru Asahi

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   138 ( 45 ) 15066 - 15077  2016.11  [Refereed]

     View Summary

    Introducing chirality into photomechanical crystals is beneficial for the diversification of mechanical motion. Measurement of the chiroptical and optical anisotropic properties of chiral crystals is indispensable for evaluating photomechanical crystals. The platelike crystals of S- and R-enantiomers of photochromic N-3,5-di-tert-butylsalicylidene-1-phenylethylamine in enol form (enol-(S)-1 and enol-(R)-1) caused bending motion with twisting upon ultraviolet (UV) light irradiation, due to shrinkage along the length and width directions of the irradiated surface, based on the optimized crystal structure of the photoisomerized trans-keto-(S)-1. By employing the generalized high-accuracy universal polarimeter (G-HAUP), optical anisotropic (linear birefringence, LB; linear dichroism, LD) as well as chiroptical (circular birefringence, CB; circular dichroism, CD) spectra of both the enantiomeric crystals on the (001) face were simultaneously measured before and under continuous UV irradiation. The LD peak was observed at 330 nm in the negative sign, derived from the pi-pi* transition of the intramolecularly hydrogen-bonded salicylidenimino moiety. The CD spectra of the S and R crystals revealed the negative and positive Cotton effect at 330 nm, respectively, and new peaks appeared at 460 rim under UV light irradiation due to photoisomerization to the S and R trans-keto isomers at around 10% conversion. The CB and CD spectra evaluated by the HAUP measurement were opposite to those measured in the hexane solution, as well as those simulated by quantum chemical calculation. The dissymmetry parameter, g, of the enol-(S)-1 crystal along the c axis (0.013) was approximately 10 times larger than the g values in the solution (0.0010) and by calculation (0.0016).

    DOI

  • Solid-State Photochemical Reaction of Multisubstituted Thymine Derivatives

    Akihiro Udagawa, Priscilla Johnston, Hidehiro Uekusa, Hideko Koshima, Kei Saito, Toni Asahi

    ACS SUSTAINABLE CHEMISTRY & ENGINEERING   4 ( 11 ) 6107 - 6114  2016.11  [Refereed]

     View Summary

    Solid-state photochemical reactions in crystals, known as topochemical reactions, are solvent-free green chemical reactions that produce stereospecific molecules. The photoreaction of thymine is interesting because the dimeric photoproduct can form four types of stereoisomers and when the dimer is formed in DNA helices it can cause skin cancers. We investigated the photoreaction of five multisubstituted thymine derivatives in the solid-state, which were designed with crystal engineering concepts to promote pi-pi stacking of benzene rings in the crystal. Powder X-ray diffraction analysis revealed that a para-substituted bis-thymine derivative was aligned along the c axis in the crystal and was susceptible to topochemical reaction to form a polymer, as previously reported. Ortho- and meta-substituted bis-thymine derivatives and a tetrakis-substituted derivative were found to be topochemically unreactive using both gel permeation chromatography (GPC) and X-ray crystal structural analysis. The tris-substituted thymine derivative was found to be topochemically reactive due to favorable crystal packing, which included ethanol molecules to form hydrogen bonding with one of the thymine moieties and stabilize the crystal packing. GPC and crystal structural analysis revealed that it could form tetramer at most via topochemical [2+2]-cycloaddition upon UV irradiation. Based on the crystal structure of the tris-substituted thymine derivative, the structure of the tetrameric photoproduct is expected to link via cis-syn, trans-anti and cis-syn cyclobutane isomers.

    DOI

  • Nuclear cereblon modulates transcriptional activity of Ikaros and regulates its downstream target, enkephalin, in human neuroblastoma cells

    Takeyoshi Wada, Toru Asahi, Naoya Sawamura

    BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS   477 ( 3 ) 388 - 394  2016.08  [Refereed]

     View Summary

    The gene coding cereblon (CRBN) was originally identified in genetic linkage analysis of mild autosomal recessive nonsyndromic intellectual disability. CRBN has broad localization in both the cytoplasm and nucleus. However, the significance of nuclear CRBN remains unknown. In the present study, we aimed to elucidate the role of CRBN in the nucleus. First, we generated a series of CRBN deletion mutants and determined the regions responsible for the nuclear localization. Only CRBN protein lacking the N-terminal region was localized outside of the nucleus, suggesting that the N-terminal region is important for its nuclear localization. CRBN was also identified as a thalidomide-binding protein and component of the cullin-4-containing E3 ubiquitin ligase complex. Thalidomide has been reported to be involved in the regulation of the transcription factor Ikaros by CRBN-mediated degradation. To investigate the nuclear functions of CRBN, we performed co-immunoprecipitation experiments and evaluated the binding of CRBN to Ikaros. As a result, we found that CRBN was associated with Ikaros protein, and the N-terminal region of CRBN was required for Ikaros binding. In luciferase reporter gene experiments, CRBN modulated transcriptional activity of Ikaros. Furthermore, we found that CRBN modulated Ikaros-mediated transcriptional repression of the proenkephalin gene by binding to its promoter region. These results suggest that CRBN binds to Ikaros via its N-terminal region and regulates transcriptional activities of Ikaros and its downstream target, enkephalin. (C) 2016 Elsevier Inc. All rights reserved.

    DOI PubMed

  • Mitochondrial cereblon functions as a Lon-type protease

    Kosuke Kataoka, China Nakamura, Toru Asahi, Naoya Sawamura

    SCIENTIFIC REPORTS   6  2016.07  [Refereed]

     View Summary

    Lon protease plays a major role in the protein quality control system in mammalian cell mitochondria. It is present in the mitochondrial matrix, and degrades oxidized and misfolded proteins, thereby protecting the cell from various extracellular stresses, including oxidative stress. The intellectual disability-associated and thalidomide-binding protein cereblon (CRBN) contains a large, highly conserved Lon domain. However, whether CRBN has Lon protease-like function remains unknown. Here, we determined if CRBN has a protective function against oxidative stress, similar to Lon protease. We report that CRBN partially distributes in mitochondria, suggesting it has a mitochondrial function. To specify the mitochondrial role of CRBN, we mitochondrially expressed CRBN in human neuroblastoma SH-SY5Y cells. The resulting stable SH-SY5Y cell line showed no apparent effect on the mitochondrial functions of fusion, fission, and membrane potential. However, mitochondrially expressed CRBN exhibited protease activity, and was induced by oxidative stress. In addition, stably expressed cells exhibited suppressed neuronal cell death induced by hydrogen peroxide. These results suggest that CRBN functions specifically as a Lon-type protease in mitochondria.

    DOI

  • Mechanical Motion of Chiral Azobenzene Crystals with Twisting upon Photoirradiation

    Takuya Taniguchi, Juri Fujisawa, Motoo Shiro, Hideko Koshima, Toru Asahi

    CHEMISTRY-A EUROPEAN JOURNAL   22 ( 23 ) 7950 - 7958  2016.06  [Refereed]

     View Summary

    The photomechanical motion of chiral crystals of trans-azobenzene derivatives with an (S)- and (R)-phenylethylamide group was investigated and compared with a racemic crystal. Changes in the UV/Vis absorption spectra of the powdered crystals before and after UV irradiation were measured by using an optical waveguide spectrometer, showing that the lifetime of the cis-to-trans thermal backisomerization of the chiral crystals was faster than that of the racemic crystals. Upon UV irradiation, a long plate-like chiral microcrystal bent away from the light source with a twisting motion. A square-like chiral microcrystal curled toward the light with some twisting. Reversible bending of a rod-like chiral microcrystal was repeatable over twenty-five cycles. In contrast, bending of a plate-like racemic microcrystal was small. A possible mechanism for the bending and twisting motion was discussed based on the optimized cis conformer determined by using calculations, showing that the bending motion with twisting is caused by elongation along the b axis and shrinkage along the a axis.

    DOI

  • Microwave Effect on Fischer Esterification

    Hideko Koshima, Kiminori Miyazaki, Saori Ishii, Tom Asahi

    CHEMISTRY LETTERS   45 ( 5 ) 505 - 507  2016.05  [Refereed]

     View Summary

    Upon microwave irradiation, esterification of octanoic acid with 1-octanol in the presence of hydrochloric acid as an acid catalyst proceeded more efficiently in glass vessels than in silicon carbide (SiC) vessels, affording 1-octyl octanoate in higher yields and revealing microwave effects during esterification.

    DOI CiNii

  • Absolute Structure Determination of Chiral Crystals Consisting of Achiral Benzophenone with Single-crystal X-ray Diffraction and Its Correlation with Solid-state Circular Dichroism

    Arimasa Matsumoto, Sumeru Tsuchiya, Yuki Hagiwara, Kazuhiko Ishikawa, Hideko Koshima, Toru Asahi, Kenso Soai

    CHEMISTRY LETTERS   45 ( 5 ) 526 - 528  2016.05  [Refereed]

     View Summary

    Achiral benzophenone is one of the simplest organic aromatic ketones that crystallize in the chiral form. The absolute structure of chiral crystals consisting of achiral benzophenone was firstly determined with single-crystal X-ray diffraction analysis and the absolute structure was successfully correlated with the solid-state circular dichroism spectra.

    DOI CiNii

  • Absolute Structure Determination of Chiral Crystals Consisting of Achiral Benzophenone with Single-crystal X-ray Diffraction and Its Correlation with Solid-state Circular Dichroism

    Arimasa Matsumoto, Sumeru Tsuchiya, Yuki Hagiwara, Kazuhiko Ishikawa, Hideko Koshima, Toru Asahi, Kenso Soai

    CHEMISTRY LETTERS   45 ( 5 ) 526 - 528  2016.05  [Refereed]

     View Summary

    Achiral benzophenone is one of the simplest organic aromatic ketones that crystallize in the chiral form. The absolute structure of chiral crystals consisting of achiral benzophenone was firstly determined with single-crystal X-ray diffraction analysis and the absolute structure was successfully correlated with the solid-state circular dichroism spectra.

    DOI

  • Interfacial effects on the crystallization and surface properties of poly(l- lactic acid) ultrathin films

    Akihiro Udagawa, Toshinori Fujie, Yuko Kawamoto, Akihiro Saito, Shinji Takeoka, Toru Asahi

    POLYMER JOURNAL   48 ( 2 ) 157 - 161  2016.02  [Refereed]

     View Summary

    Polymer crystallization affects structural and mechanical properties of polymer thin films. In this study, we focused on the thermal annealing-induced crystallization in semi-crystalline poly(l-lactic acid) (PLLA) ultrathin films (referred as nanosheets) was investigated in terms of interfacial interaction of PLLA with air and substrate. The surface structure of the PLLA nanosheets observed by atomic force microscopy showed that roughness of the air-side surface increased due to crystallization of PLLA under thermal annealing, whereas that of the substrate-side surface changed little. The elastic moduli and the physical adhesiveness of the nanosheets also changed only on the surface of the air side from crystallization, in contrast to the substrate side. The X-ray diffraction studies of the PLLA nanosheets with different thickness showed that the crystalline contents steeply increased below ca. 200 nm. These results indicated that the crystallization was enhanced near the surface of the air side and restricted near that of the substrate side due to the different interfacial association of the polymer chains in the nanosheet.

    DOI

  • Microwave Effect on Fischer Esterification

    Koshima Hideko, Miyazaki Kiminori, Ishii Saori, Asahi Toru

    Chemistry Letters   0 ( 0 )  2016  [Refereed]

     View Summary

    Upon microwave irradiation, esterification of octanoic acid with 1-octanol in the presence of hydrochloric acid as an acid catalyst proceeded more efficiently in glass vessels than in silicon carbide (SiC) vessels, affording 1-octyl octanoate at higher yields and revealing microwave effects during esterification.

    CiNii

  • Mechanical motion of molecular crystals induced by [4+4] photodimerisation

    Hideko Koshima, Hidetaka Uchimoto, Takuya Taniguchi, Jun Nakamura, Tsuyoshi Asahi, Toru Asahi

    CRYSTENGCOMM   18 ( 38 ) 7305 - 7310  2016  [Refereed]

     View Summary

    The photomechanical bending of crystals of a stilbene-type compound substituted with anthracene and indanone groups, (E)-2-(9-anthrylmethylene)-1-indanone (trans-1), was investigated. When a narrow plate-like microcrystal was irradiated with ultraviolet (UV) light at 365 nm, the crystal gradually bent away from the light source and finally reached a semicircular shape after more than 10 min. A larger rod-like crystal, approximately 10 mm in length, also exhibited a slight bending motion. The cessation of UV irradiation caused the bent crystals to return very slowly to their straight form. In the crystals, the anthracene planes of two neighbouring trans-1 molecules are arranged in a head-to-tail parallel manner, with a short plane-to-plane distance of only 3.72 angstrom. The H-1 nuclear magnetic resonance spectra of trans-1 crystals before and after UV irradiation revealed the intermolecular [4 + 4] photodimerisation of the two anthracene planes, while the trans-to-cis photoisomerisation was not significant. The UV-vis absorption spectra of the trans-1 powder crystals, obtained using a diffuse reflectance spectrophotometer, showed a gradual increase in absorbance between 200 and 500 nm with increasing UV irradiation time, reaching a maximum after 1 h. Thermal back-monomerisation was very slow in the dark, not recovering the initial spectrum even after 25 days. The fluorescence spectra at 570 nm, derived from the anthracene excimer, decreased in intensity with increasing UV irradiation time due to a decrease in the amount of anthracene chromophore via photodimerisation. In situ X-ray measurements revealed that the bending of the crystals was caused by slight elongation of the b axis of the unit cell, corresponding to the long axis of the rod-like crystals. Calculations revealed that the observed crystal elongation could be explained by an optimised head-to-tail [4 + 4] orientation of the anthracene dimer.

    DOI

  • Cereblon is recruited to aggresome and shows cytoprotective effect against ubiquitin-proteasome system dysfunction

    Naoya Sawamura, Satoru Wakabayashi, Kodai Matsumoto, Haruka Yamada, Toru Asahi

    Biochemical and Biophysical Research Communications   464 ( 4 ) 1054 - 1059  2015.09

     View Summary

    Cereblon (CRBN) is encoded by a candidate gene for autosomal recessive nonsyndromic intellectual disability (ID). The nonsense mutation, R419X, causes deletion of 24 amino acids at the C-terminus of CRBN, leading to mild ID. Although abnormal CRBN function may be associated with ID disease onset, its cellular mechanism is still unclear. Here, we examine the role of CRBN in aggresome formation and cytoprotection. In the presence of a proteasome inhibitor, exogenous CRBN formed perinuclear inclusions and co-localized with aggresome markers. Endogenous CRBN also formed perinuclear inclusions under the same condition. Treatment with a microtubule destabilizer or an inhibitor of the E3 ubiquitin ligase activity of CRBN blocked formation of CRBN inclusions. Biochemical analysis showed CRBN containing inclusions were high-molecular weight, ubiquitin-positive. CRBN overexpression in cultured cells suppressed cell death induced by proteasome inhibitor. Furthermore, knockdown of endogenous CRBN in cultured cells increased cell death induced by proteasome inhibitor, compared with control cells. Our results show CRBN is recruited to aggresome and has functional roles in cytoprotection against ubiquitin-proteasome system impaired condition.

    DOI PubMed

  • Cereblon is recruited to aggresome and shows cytoprotective effect against ubiquitin-proteasome system dysfunction

    Naoya Sawamura, Satoru Wakabayashi, Kodai Matsumoto, Haruka Yamada, Toru Asahi

    BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS   464 ( 4 ) 1054 - 1059  2015.09  [Refereed]

     View Summary

    Cereblon (CRBN) is encoded by a candidate gene for autosomal recessive nonsyndromic intellectual disability (ID). The nonsense mutation, R419X, causes deletion of 24 amino acids at the C-terminus of CRBN, leading to mild ID. Although abnormal CRBN function may be associated with ID disease onset, its cellular mechanism is still unclear. Here, we examine the role of CRBN in aggresome formation and cytoprotection. In the presence of a proteasome inhibitor, exogenous CRBN formed perinuclear inclusions and co-localized with aggresome markers. Endogenous CRBN also formed perinuclear inclusions under the same condition. Treatment with a microtubule destabilizer or an inhibitor of the E3 ubiquitin ligase activity of CRBN blocked formation of CRBN inclusions. Biochemical analysis showed CRBN containing inclusions were high-molecular weight, ubiquitin-positive. CRBN overexpression in cultured cells suppressed cell death induced by proteasome inhibitor. Furthermore, knockdown of endogenous CRBN in cultured cells increased cell death induced by proteasome inhibitor, compared with control cells. Our results show CRBN is recruited to aggresome and has functional roles in cytoprotection against ubiquitin-proteasome system impaired condition. (C) 2015 Elsevier Inc. All rights reserved.

    DOI

  • Cereblon is recruited to aggresome and shows cytoprotective effect against ubiquitin-proteasome system dysfunction

    Naoya Sawamura, Satoru Wakabayashi, Kodai Matsumoto, Haruka Yamada, Toru Asahi

    BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS   464 ( 4 ) 1054 - 1059  2015.09  [Refereed]

     View Summary

    Cereblon (CRBN) is encoded by a candidate gene for autosomal recessive nonsyndromic intellectual disability (ID). The nonsense mutation, R419X, causes deletion of 24 amino acids at the C-terminus of CRBN, leading to mild ID. Although abnormal CRBN function may be associated with ID disease onset, its cellular mechanism is still unclear. Here, we examine the role of CRBN in aggresome formation and cytoprotection. In the presence of a proteasome inhibitor, exogenous CRBN formed perinuclear inclusions and co-localized with aggresome markers. Endogenous CRBN also formed perinuclear inclusions under the same condition. Treatment with a microtubule destabilizer or an inhibitor of the E3 ubiquitin ligase activity of CRBN blocked formation of CRBN inclusions. Biochemical analysis showed CRBN containing inclusions were high-molecular weight, ubiquitin-positive. CRBN overexpression in cultured cells suppressed cell death induced by proteasome inhibitor. Furthermore, knockdown of endogenous CRBN in cultured cells increased cell death induced by proteasome inhibitor, compared with control cells. Our results show CRBN is recruited to aggresome and has functional roles in cytoprotection against ubiquitin-proteasome system impaired condition. (C) 2015 Elsevier Inc. All rights reserved.

    DOI PubMed

  • 19aPS-14 Optical property and symmetry breaking of cupper-oxide based high-temperature superconducting material Bi_2Sr_2CaCu_2O_<8+x>

    Matsumoto M, Nakagawa K, Watauchi S, Matsuda A, Asahi T

      70 ( 2 )  2015.09

    CiNii

  • 18pPSA-61 Magneto-optical study on Cerium fluoride crystal with the G-HAUP

    Nakagawa K, Villora G, Shimamura K, Asahi T

      70 ( 2 )  2015.09

    CiNii

  • Model of complex chiral drug metabolic systems and numerical simulation of the remaining chirality toward analysis of dynamical pharmacological activity

    Yoshiyuki Ogino, Toru Asahi

    JOURNAL OF THEORETICAL BIOLOGY   373   117 - 131  2015.05  [Refereed]

     View Summary

    In this study, systems of complicated pathways involved in chiral drug metabolism were investigated. The development of chiral drugs resulted in significant improvement in the remedies available for the treatment of various severe sicknesses. Enantiopure drugs undergo various biological transformations that involve chiral inversion and thus result in the generation of multiple enantiomeric metabolites. Identification of the specific active substances determining a given drug's efficacy among such a mixture of different metabolites remains a challenge. To comprehend this complexity, we constructed a mathematical model representing the complicated metabolic pathways simultaneously involving chiral inversion. Moreover, this model is applied to the metabolism of thalidomide, which has recently been revived as a potentially effective prescription drug for a number of intractable diseases. The numerical simulation results indicate that retained chirality in the metabolites reflects the original chirality of the unmetabolized drug, and a higher level of enantiomeric purity is preserved during spontaneous degradation. In addition, chirality remaining after equilibration is directly related to the rate constant not only for chiral inversion but also for generation and degradation. Furthermore, the retention of chirality is quantitatively predictable using this combination of kinetic parameters. Our simulation results well explain the behavior of thalidomide in the practical biological experimental data. Therefore, this model promises a comprehensive understanding of dynamic metabolic systems involving chiral drugs that express multiple enantiospecific drug efficacies. (C) 2015 Elsevier Ltd. All rights reserved.

    DOI

  • Model of complex chiral drug metabolic systems and numerical simulation of the remaining chirality toward analysis of dynamical pharmacological activity

    Yoshiyuki Ogino, Toru Asahi

    JOURNAL OF THEORETICAL BIOLOGY   373   117 - 131  2015.05  [Refereed]

     View Summary

    In this study, systems of complicated pathways involved in chiral drug metabolism were investigated. The development of chiral drugs resulted in significant improvement in the remedies available for the treatment of various severe sicknesses. Enantiopure drugs undergo various biological transformations that involve chiral inversion and thus result in the generation of multiple enantiomeric metabolites. Identification of the specific active substances determining a given drug's efficacy among such a mixture of different metabolites remains a challenge. To comprehend this complexity, we constructed a mathematical model representing the complicated metabolic pathways simultaneously involving chiral inversion. Moreover, this model is applied to the metabolism of thalidomide, which has recently been revived as a potentially effective prescription drug for a number of intractable diseases. The numerical simulation results indicate that retained chirality in the metabolites reflects the original chirality of the unmetabolized drug, and a higher level of enantiomeric purity is preserved during spontaneous degradation. In addition, chirality remaining after equilibration is directly related to the rate constant not only for chiral inversion but also for generation and degradation. Furthermore, the retention of chirality is quantitatively predictable using this combination of kinetic parameters. Our simulation results well explain the behavior of thalidomide in the practical biological experimental data. Therefore, this model promises a comprehensive understanding of dynamic metabolic systems involving chiral drugs that express multiple enantiospecific drug efficacies. (C) 2015 Elsevier Ltd. All rights reserved.

    DOI PubMed

  • Model of complex chiral drug metabolic systems and numerical simulation of the remaining chirality toward analysis of dynamical pharmacological activity.

    Ogino Yoshiyuki, Asahi Toru

    Journal of theoretical biology   373  2015

     View Summary

    :In this study, systems of complicated pathways involved in chiral drug metabolism were investigated. The development of chiral drugs resulted in significant improvement in the remedies available for the treatment of various severe sicknesses. Enantiopure drugs undergo various biological transformations that involve chiral inversion and thus result in the generation of multiple enantiomeric metabolites. Identification of the specific active substances determining a given drug׳s efficacy among such a mixture of different metabolites remains a challenge. To comprehend this complexity, we constructed a mathematical model representing the complicated metabolic pathways simultaneously involving chiral inversion. Moreover, this model is applied to the metabolism of thalidomide, which has recently been revived as a potentially effective prescription drug for a number of intractable diseases. The numerical simulation results indicate that retained chirality in the metabolites reflects the original chirality of the unmetabolized drug, and a higher level of enantiomeric purity is preserved during spontaneous degradation. In addition, chirality remaining after equilibration is directly related to the rate constant not only for chiral inversion but also for generation and degradation. Furthermore, the retention of chirality is quantitatively predictable using this combination of kinetic parameters. Our simulation results well explain the behavior of thalidomide in the practical biological experimental data. Therefore, this model promises a comprehensive understanding of dynamic metabolic systems involving chiral drugs that express multiple enantiospecific drug efficacies.

    DOI PubMed

  • Crystal structure of (S)-4-carbamoyl-4-(1, 3-dioxo-isoindolin-2-yl)butanoic acid

    Kohei Otogawa, Kazuhiko Ishikawa, Motoo Shiro, Toru Asahi, H. Ishida

    Acta Crystallographica Section E: Structure Reports Online   71 ( 1 ) 107 - 109  2015.01

     View Summary

    In the title compound, C&lt
    inf&gt
    13&lt
    /inf&gt
    H&lt
    inf&gt
    12&lt
    /inf&gt
    N&lt
    inf&gt
    2&lt
    /inf&gt
    O&lt
    inf&gt
    5&lt
    /inf&gt
    , the phthalimide ring system is essentially planar, with a maximum deviation of 0.0479 (14) Å. In the crystal, each molecule is linked via six neighbouring molecules into a three-dimensional network through N - H⋯O and O - H⋯O hydrogen bonds, which form an R &lt
    inf&gt
    3&lt
    /inf&gt
    &lt
    sup&gt
    2&lt
    /sup&gt
    (8) ring motif.

    DOI PubMed

  • Self-disproportionation of enantiomers of thalidomide and its fluorinated analogue via gravity-driven achiral chromatography: mechanistic rationale and implications

    Mayaka Maeno, Etsuko Tokunaga, Takeshi Yamamoto, Toshiya Suzuki, Yoshiyuki Ogino, Emi Ito, Motoo Shiro, Toru Asahi, Norio Shibata

    CHEMICAL SCIENCE   6 ( 2 ) 1043 - 1048  2015  [Refereed]

     View Summary

    We report on the self-disproportionation of enantiomers (SDE) of non-racemic thalidomide (1) and 3'-fluorothalidomide (2) under the conditions of gravity-driven achiral silica-gel chromatography. The presence of a fluorine atom on the chiral center dramatically alters the structure and polarity of 1 and 2, resulting in the opposite SDE profile on silica-gel.

    DOI

  • Arctic mutant A beta 40 aggregates on alpha 7 nicotinic acetylcholine receptors and inhibits their functions

    Ye Ju, Toru Asahi, Naoya Sawamura

    JOURNAL OF NEUROCHEMISTRY   131 ( 5 ) 667 - 674  2014.12  [Refereed]

     View Summary

    Amyloid protein (A beta) plays a central role in the pathogenesis of Alzheimer's disease (AD). Point mutations within the A sequence associated with familial AD (FAD) are clustered around the central hydrophobic core of A. Several types of mutations within the A sequence have been identified, and the Arctic' mutation (E22G) has a purely cognitive phenotype typical of AD. Previous studies have shown that the primary result of the Arctic' mutation is increased formation of A protofibrils. However, the molecular mechanism underlying this effect remains unknown. A42 binds to a neuronal nicotinic acetylcholine receptor subunit, neuronal acetylcholine receptor subunit alpha-7 (CHRNA7), with high affinity and, thus, may be involved in the pathogenesis of AD. Therefore, to clarify the molecular mechanism of Arctic mutation-mediated FAD, we focused on CHRNA7 as a target molecule of Arctic A. We performed an in vitro binding assay using purified CHRNA7 and synthetic Arctic A40, and demonstrated that Arctic A40 specifically bound to CHRNA7. The aggregation of Arctic A40 was enhanced with the addition of CHRNA7. Furthermore, the function of CHRNA7 was detected by measuring Ca2+ flux and phospho-p44/42 MAPK (ERK1/2) activation. Our results indicated that Arctic A40 aggregation was enhanced by the addition of CHRNA7, which destabilized the function of CHRNA7 via inhibition of Ca2+ responses and activation of ERK1/2. These findings indicate that Arctic A mutation may be involved in the mechanism underlying FAD. This mechanism may involve binding and aggregation, leading to the inhibition of CHRNA7 functions.

    DOI

  • Arctic mutatn Aβ40 aggregates on α7 nicotinic acetylcholine receptors and inhibits their functions

    Ye Ju, Toru Asahi, Naoya Sawamura

    Journal of Neurochemistry    2014.08

  • Quantitative analysis with advanced compensated polarized light microscopy on wavelength dependence of linear birefringence of single crystals causing arthritis

    Akifumi Takanabe, Masahito Tanaka, Atsuo Taniguchi, Hisashi Yamanaka, Toru Asahi

    JOURNAL OF PHYSICS D-APPLIED PHYSICS   47 ( 28 )  2014.07  [Refereed]

     View Summary

    To improve our ability to identify single crystals causing arthritis, we have developed a practical measurement system of polarized light microscopy called advanced compensated polarized light microscopy (A-CPLM). The A-CPLM system is constructed by employing a conventional phase retardation plate, an optical fibre and a charge-coupled device spectrometer in a polarized light microscope. We applied the A-CPLM system to measure linear birefringence (LB) in the visible region, which is an optical anisotropic property, for tiny single crystals causing arthritis, i.e. monosodium urate monohydrate (MSUM) and calcium pyrophosphate dihydrate (CPPD). The A-CPLM system performance was evaluated by comparing the obtained experimental data using the A-CPLM system with (i) literature data for a standard sample, MgF2, and (ii) experimental data obtained using an established optical method, high-accuracy universal polarimeter, for the MSUM. The A-CPLM system was found to be applicable for measuring the LB spectra of the single crystals of MSUM and CPPD, which cause arthritis, in the visible regions. We quantitatively reveal the large difference in LB between MSUM and CPPD crystals. These results demonstrate the usefulness of the A-CPLM system for distinguishing the crystals causing arthritis.

    DOI

  • Quantitative analysis with advanced compensated polarized light microscopy on wavelength dependence of linear birefringence of single crystals causing arthritis

    Akifumi Takanabe, Masahito Tanaka, Atsuo Taniguchi, Hisashi Yamanaka, Toru Asahi

    Journal of Physics D: Applied Physics   47 ( 28 ) 285402  2014.06

  • A label-free electrical assay of fibrous amyloid β based on semiconductor biosensing

    Sho Hideshima, Masumi Kobayashi, Takeyoshi Wada, Shigeki Kuroiwa, Takuya Nakanishi, Naoya Sawamura, Toru Asahi, Tetsuya Osaka

    Chemical Communications   50 ( 26 ) 3476 - 3479  2014.04

     View Summary

    We propose, as an alternative to conventional spectroscopic assays, a simple method for discriminating fibrous amyloid proteins by using a label-free semiconductor-based biosensor. The highly sensitive assay is expected to be useful for accelerating amyloid related research. © 2014 The Royal Society of Chemistry.

    DOI PubMed

  • A high-accuracy universal polarimeter study of optical anisotropy and optical activity in laminated collagen membranes

    Kenta Nakagawa, Heather Harper-Lovelady, Yuji Tanaka, Masahito Tanaka, Masayuki Yamato, Toru Asahi

    CHEMICAL COMMUNICATIONS   50 ( 95 ) 15086 - 15089  2014

     View Summary

    A novel method for fabricating anisotropic collagen membranes, which regulate the preferred orientation, is developed. The high-accuracy universal polarimeter (HAUP) method is used for simultaneous and quantitative evaluations of the optical anisotropy and optical activity. The evaluation of these optical quantities, enabled by the HAUP method, is beneficial to the field of tissue engineering.

    DOI

  • A high-accuracy universal polarimeter study of optical anisotropy and optical activity in laminated collagen membranes.

    Nakagawa Kenta, Harper-Lovelady Heather, Tanaka Yuji, Tanaka Masahito, Yamato Masayuki, Asahi Toru

    A high-accuracy universal polarimeter study of optical anisotropy and optical activity in laminated collagen membranes.   50 ( 95 )  2014

     View Summary

    :A novel method for fabricating anisotropic collagen membranes, which regulate the preferred orientation, is developed. The high-accuracy universal polarimeter (HAUP) method is used for simultaneous and quantitative evaluations of the optical anisotropy and optical activity. The evaluation of these optical quantities, enabled by the HAUP method, is beneficial to the field of tissue engineering.

    DOI

  • Arctic mutant Aβ40 aggregates on α7 nicotinic acetylcholine receptors and inhibits their functions

    Ye Ju, Toru Asahi, Naoya Sawamura

    Journal of Neurochemistry   131 ( 5 ) 667 - 674  2014

     View Summary

    Amyloid β protein (Aβ) plays a central role in the pathogenesis of Alzheimer's disease (AD). Point mutations within the Aβ sequence associated with familial AD (FAD) are clustered around the central hydrophobic core of Aβ. Several types of mutations within the Aβ sequence have been identified, and the 'Arctic' mutation (E22G) has a purely cognitive phenotype typical of AD. Previous studies have shown that the primary result of the 'Arctic' mutation is increased formation of Aβ protofibrils. However, the molecular mechanism underlying this effect remains unknown. Aβ42 binds to a neuronal nicotinic acetylcholine receptor subunit, neuronal acetylcholine receptor subunit alpha-7 (CHRNA7), with high affinity and, thus, may be involved in the pathogenesis of AD. Therefore, to clarify the molecular mechanism of Arctic mutation-mediated FAD, we focused on CHRNA7 as a target molecule of Arctic Aβ. We performed an in vitro binding assay using purified CHRNA7 and synthetic Arctic Aβ40, and demonstrated that Arctic Aβ40 specifically bound to CHRNA7. The aggregation of Arctic Ab40 was enhanced with the addition of CHRNA7. Furthermore, the function of CHRNA7 was detected by measuring Ca2+ flux and phospho-p44/42 MAPK (ERK1/2) activation. Our results indicated that Arctic Aβ40 aggregation was enhanced by the addition of CHRNA7, which destabilized the function of CHRNA7 via inhibition of Ca2+ responses and activation of ERK1/2. These findings indicate that Arctic Aβ mutation may be involved in the mechanism underlying FAD. This mechanism may involve binding and aggregation, leading to the inhibition of CHRNA7 functions.

    DOI PubMed

  • A label-free electrical assay of fibrous amyloid beta based on semiconductor biosensing

    Sho Hideshima, Masumi Kobayashi, Takeyoshi Wada, Shigeki Kuroiwa, Takuya Nakanishi, Naoya Sawamura, Toru Asahi, Tetsuya Osaka

    CHEMICAL COMMUNICATIONS   50 ( 26 ) 3476 - 3479  2014  [Refereed]

     View Summary

    We propose, as an alternative to conventional spectroscopic assays, a simple method for discriminating fibrous amyloid proteins by using a label-free semiconductor-based biosensor. The highly sensitive assay is expected to be useful for accelerating amyloid related research.

    DOI

  • A high-accuracy universal polarimeter study of optical anisotropy and optical activity in laminated collagen membranes

    Kenta Nakagawa, Heather Harper-Lovelady, Yuji Tanaka, Masahito Tanaka, Masayuki Yamato, Toru Asahi

    CHEMICAL COMMUNICATIONS   50 ( 95 ) 15086 - 15089  2014  [Refereed]

     View Summary

    A novel method for fabricating anisotropic collagen membranes, which regulate the preferred orientation, is developed. The high-accuracy universal polarimeter (HAUP) method is used for simultaneous and quantitative evaluations of the optical anisotropy and optical activity. The evaluation of these optical quantities, enabled by the HAUP method, is beneficial to the field of tissue engineering.

    DOI

  • A label-free electrical assay of fibrous amyloid beta based on semiconductor biosensing

    Sho Hideshima, Masumi Kobayashi, Takeyoshi Wada, Shigeki Kuroiwa, Takuya Nakanishi, Naoya Sawamura, Toru Asahi, Tetsuya Osaka

    CHEMICAL COMMUNICATIONS   50 ( 26 ) 3476 - 3479  2014

     View Summary

    We propose, as an alternative to conventional spectroscopic assays, a simple method for discriminating fibrous amyloid proteins by using a label-free semiconductor-based biosensor. The highly sensitive assay is expected to be useful for accelerating amyloid related research.

    DOI

  • Carrier Design and Graduate School Reform for Postadoctoral Fellows and Doctoral Students in Science and Engineering(Network Pages for Professional Development of Physicists)

    Asahi Toru, Nakazato Hiromichi, Suzuki Kiyotaka

      68 ( 9 ) 623 - 627  2013.09

    CiNii

  • Metastable Liquid Crystal as Time-Responsive Reaction Medium: Aging-Induced Dual Enantioselective Control

    Yasuhiro Ishida, Yuki Matsuoka, Yukiko Kai, Kuniyo Yamada, Kenta Nakagawa, Toru Asahi, Kazuhiko Saigo

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   135 ( 17 ) 6407 - 6410  2013.05  [Refereed]

     View Summary

    A metastable liquid crystal (LC) was found to serve as a time responsive reaction medium, in which the enantioselectivity of a photoreaction was perfectly switched through isothermal annealing of the reaction system. When the LC salt of an enantiopure amine with a photoreactive acid was irradiated with UV/vis light, in situ, photodimerization of the acid moiety proceeded smoothly to afford the (+)-isomer of the photodimer with high enantioselectivity (+86% ee). In contrast, photoirradiation of an aged sample, isothermally annealed for 20 h, gave predominantly the (-)-isomer (-94% ee). Systematic studies revealed that the reversal in selectivity originated from metastability. of the LC system, which gradually transformed into a crystalline phase during annealing. This finding demonstrates the potential use of metastable aggregates as dynamic time-responsive media, reminiscent of biological systems.

    DOI

  • Metastable Liquid Crystal as Time-Responsive Reaction Medium: Aging-Induced Dual Enantioselective Control

    Yasuhiro Ishida, Yuki Matsuoka, Yukiko Kai, Kuniyo Yamada, Kenta Nakagawa, Toru Asahi, Kazuhiko Saigo

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   135 ( 17 ) 6407 - 6410  2013.05

     View Summary

    A metastable liquid crystal (LC) was found to serve as a time responsive reaction medium, in which the enantioselectivity of a photoreaction was perfectly switched through isothermal annealing of the reaction system. When the LC salt of an enantiopure amine with a photoreactive acid was irradiated with UV/vis light, in situ, photodimerization of the acid moiety proceeded smoothly to afford the (+)-isomer of the photodimer with high enantioselectivity (+86% ee). In contrast, photoirradiation of an aged sample, isothermally annealed for 20 h, gave predominantly the (-)-isomer (-94% ee). Systematic studies revealed that the reversal in selectivity originated from metastability. of the LC system, which gradually transformed into a crystalline phase during annealing. This finding demonstrates the potential use of metastable aggregates as dynamic time-responsive media, reminiscent of biological systems.

    DOI

  • Construction of photoenergetic mitochondria in cultured mammalian cells

    Kiyotaka Y. Hara, Takeyoshi Wada, Kuniki Kino, Toru Asahi, Naoya Sawamura

    Scientific Reports   3 ( 1635 )  2013.04

     View Summary

    The proton motive force (PMF) is bio-energetically important for various cellular reactions to occur. We developed PMF-photogenerating mitochondria in cultured mammalian cells. An archaebacterial rhodopsin, delta-rhodopsin, which is a light-driven proton pump derived from Haloterrigena turkmenica, was expressed in the mitochondria of CHO-K1 cells. The constructed stable CHO-K1 cell lines showed suppression of cell death induced by rotenone, a pesticide that inhibits mitochondrial complex I activity involved in PMF generation through the electron transport chain. Delta-rhodopsin was also introduced into the mitochondria of human neuroblastoma SH-SY5Y cells. The constructed stable SH-SY5Y cell lines showed suppression of dopaminergic neuronal cell death induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), an inducer of Parkinson's disease models, which acts through inhibition of complex I activity. These results suggest that the light-activated proton pump functioned as a PMF generator in the mitochondria of mammalian cells, and suppressed cell death induced by inhibition of respiratory PMF generation.

    DOI PubMed

  • Construction of photoenergetic mitochondria in cultured mammalian cells

    Kiyotaka Y. Hara, Takeyoshi Wada, Kuniki Kino, Toru Asahi, Naoya Sawamura

    Scientific Reports   3 ( 1635 )  2013.04

  • Selective Molecular Permeability Induced by Glass Transition Dynamics of Semicrystalline Polymer Ultrathin Films

    Toshinori Fujie, Yuko Kawamoto, Hiroki Haniuda, Akihiro Saito, Koki Kabata, Yukio Honda, Eriko Ohmori, Toru Asahi, Shinji Takeoka

    MACROMOLECULES   46 ( 2 ) 395 - 402  2013.01  [Refereed]

     View Summary

    Most polymers solidify below a glass transition temperature (;), which is important for the fabrication of polymeric materials. The glass transition dynamics (GTD) of polymers alters their physical properties and therefore the range of applications suitable for the particular materials. In this regard, most GTD studies were oriented to the thermodynamics of amorphous polymer systems, while little studies were known for semicrystalline polymers. Here, we focus on the glassy and crystalline properties of semicrystalline polymers such as poly(L-lactic acid) (PLLA) and envisage to control the nanostructure of free-standing PLLA ultrathin films (referred as "PLLA nanosheets"), via thermodynamic rearrangement of polymer chains entangled in a quasi-two-dimensional interface during the GTD process. The annealing process on the PLLA nanosheets (&lt;100 nm thick) resulted in the formation of semicrystalline domains and microscopic apertures with polymer chains (similar to 100 nm in size). Such nanostructure surprisingly induced selective molecular permeability, which was controlled as a function of film thickness and inherent crystallinity. The present methodology demonstrates the direct conversion of thermodynamic properties of semicrystalline polymers into the functional nanostructured polymeric materials.

    DOI

  • Selective Molecular Permeability Induced by Glass Transition Dynamics of Semicrystalline Polymer Ultrathin Films

    Toshinori Fujie, Yuko Kawamoto, Hiroki Haniuda, Akihiro Saito, Koki Kabata, Yukio Honda, Eriko Ohmori, Toru Asahi, Shinji Takeoka

    MACROMOLECULES   46 ( 2 ) 395 - 402  2013.01  [Refereed]

     View Summary

    Most polymers solidify below a glass transition temperature (;), which is important for the fabrication of polymeric materials. The glass transition dynamics (GTD) of polymers alters their physical properties and therefore the range of applications suitable for the particular materials. In this regard, most GTD studies were oriented to the thermodynamics of amorphous polymer systems, while little studies were known for semicrystalline polymers. Here, we focus on the glassy and crystalline properties of semicrystalline polymers such as poly(L-lactic acid) (PLLA) and envisage to control the nanostructure of free-standing PLLA ultrathin films (referred as "PLLA nanosheets"), via thermodynamic rearrangement of polymer chains entangled in a quasi-two-dimensional interface during the GTD process. The annealing process on the PLLA nanosheets (&lt;100 nm thick) resulted in the formation of semicrystalline domains and microscopic apertures with polymer chains (similar to 100 nm in size). Such nanostructure surprisingly induced selective molecular permeability, which was controlled as a function of film thickness and inherent crystallinity. The present methodology demonstrates the direct conversion of thermodynamic properties of semicrystalline polymers into the functional nanostructured polymeric materials.

    DOI

  • Generalized High-Accuracy Universal Polarimeter (G-HAUP) and Its Application

    ASAHI Toru, TANAKA Masahito

      61 ( 10 ) 777 - 778  2012.10

    CiNii

  • Generalized High-Accuracy Universal Polarimeter (G-HAUP) and Its Application

    T. Asahi, M. Tanaka

    Polymers (The Society of Polymer Science, Japan)   Vol.6   777 - 778  2012.10

  • An application of the advanced high-accuracy universal polarimeter to the chiroptical measurement of an intercalated compound K4Nb6O17 with high anisotropy

    Masahito Tanaka, Naomichi Nakamura, Hideko Koshima, Toru Asahi

    JOURNAL OF PHYSICS D-APPLIED PHYSICS   45 ( 17 )  2012.05  [Refereed]

     View Summary

    The advanced high-accuracy universal polarimeter (HAUP) method was applied to observe anisotropic and chiroptical properties of an intercalated azobenzene derivative compound into K4Nb6O17 crystals. Prior to the HAUP measurement of the intercalated compound, we extended the HAUP method employing a conventional light source system composed of Xe or D-2 lamps and a monochromator instead of a laser system. The performance of the advanced HAUP system was evaluated and we determined the parasitic ellipticities of the cross polarizers, which are essential for obtaining accurate values. The optical system was applicable to simultaneously measure the linear dichroism (LD), circular dichroism (CD), linear birefringence (LB) and circular birefringence (CB) spectra of an intercalated compound in the ultraviolet and visible regions. We found the Kramers-Kronig relation between CB and CD as well as in the case of LB and LD. Changes in LB and LD signals as obtained from HAUP measurements originated from the molecular orientation of guest molecules by the intercalation. Moreover, CB and CD signals indicated the appearance of induced chirality in the intercalated azobenzene derivative compound. These results demonstrated the usefulness of the HAUP system for evaluating the molecular conformation of chiral anisotropic specimens.

    DOI

  • Absolute chirality of the γ-polymorph of glycine: correlation of the absolute structure with the optical rotation

    Kazuhiko Ishikawa, Masahito Tanaka, Toshiya Suzuki, Akiko Sekine, Tsuneomi Kawasaki, Kenso Soai, Motoo Shiro, Meir Lehav, Toru Asahi

    Chemical Communications, Communication    2012.04

  • An application of the advanced high-accuracy universal polarimeter to the chiroptical measurement of an intercalated compound K4Nb6O17 with high anisotrophy

    Masahito Tanaka, Naomichi Nakamura, Hideo Koshima, Toru Asahi

    Journal of physics D: Applied physics   45   1 - 7  2012.03

  • Absolute chirality of the γ-polymorph of glycine: correlation of the absolute structure with the optical rotation.

    Ishikawa Kazuhiko, Tanaka Masahito, Suzuki Toshiya, Sekine Akiko, Kawasaki Tsuneomi, Soai Kenso, Shiro Motoo, Lahav Meir, Asahi Toru

    Absolute chirality of the γ-polymorph of glycine: correlation of the absolute structure with the optical rotation.    2012

     View Summary

    :Crystal specimens of the γ-polymorph of achiral glycine which crystallize in space groups P3(1) and P3(2) as determined by the anomalous X-ray scattering method are shown to be laevorotatory and dextrorotatory, respectively, as determined by optical rotation of the crystals.

  • Absolute chirality of the gamma-polymorph of glycine: correlation of the absolute structure with the optical rotation

    Kazuhiko Ishikawa, Masahito Tanaka, Toshiya Suzuki, Akiko Sekine, Tsuneomi Kawasaki, Kenso Soai, Motoo Shiro, Meir Lahav, Toru Asahi

    CHEMICAL COMMUNICATIONS   48 ( 48 ) 6031 - 6033  2012  [Refereed]

     View Summary

    Crystal specimens of the gamma-polymorph of achiral glycine which crystallize in space groups P3(1) and P3(2) as determined by the anomalous X-ray scattering method are shown to be laevorotatory and dextrorotatory, respectively, as determined by optical rotation of the crystals.

    DOI

  • Transparent, tough collagen laminates prepared by oriented flow casting, multi-cyclic vitrification and chemical cross-linking

    Yuji Tanaka, Koichi Baba, Thomas J. Duncan, Akira Kubota, Toru Asahi, Andrew J. Quantock, Masayuki Yamato, Teruo Okano, Kohji Nishida

    BIOMATERIALS   32 ( 13 ) 3358 - 3366  2011.05  [Refereed]

     View Summary

    The lamellar architecture found in many natural fibrous tissues has a significant bearing on their specific functions. However, current engineered tissues have simultaneously no realistic structures and no adequate functions. This study demonstrates a two-step process for obtaining structurally mimicking laminates in natural fibrous tissues with good optical and mechanical characters from purified-clinically-safe collagen molecules. Stacked lamella structures can be created by repeating flow casting, with the controlling parallel/orthogonal directionalities of each thin single-layer (2-5 mu m in thickness). The transparency of laminates is successfully improved by a unique multi-cyclic vitrification with chemical cross-linking. The directionalities of optical and mechanical functions in laminates are strongly related with the preferential collagen alignments in the laminates. The tensile strength of laminates is extremely higher than any other engineered materials as well as native cornea, which exhibit an orthogonal laminated collagen structure and a good optical transmission. (C) 2010 Elsevier Ltd. All rights reserved.

    DOI

  • Transparent, tough collagen laminates prepared by oriented flow casting, multi-cyclic vitrification and chemical cross-linking

    Yuji Tanaka, Koichi Baba, Thomas J. Duncan, Akira Kubota, Toru Asahi, Andrew J. Quantock, Masayuki Yamato, Teruo Okano, Kohji Nishida

    BIOMATERIALS   32 ( 13 ) 3358 - 3366  2011.05  [Refereed]

     View Summary

    The lamellar architecture found in many natural fibrous tissues has a significant bearing on their specific functions. However, current engineered tissues have simultaneously no realistic structures and no adequate functions. This study demonstrates a two-step process for obtaining structurally mimicking laminates in natural fibrous tissues with good optical and mechanical characters from purified-clinically-safe collagen molecules. Stacked lamella structures can be created by repeating flow casting, with the controlling parallel/orthogonal directionalities of each thin single-layer (2-5 mu m in thickness). The transparency of laminates is successfully improved by a unique multi-cyclic vitrification with chemical cross-linking. The directionalities of optical and mechanical functions in laminates are strongly related with the preferential collagen alignments in the laminates. The tensile strength of laminates is extremely higher than any other engineered materials as well as native cornea, which exhibit an orthogonal laminated collagen structure and a good optical transmission. (C) 2010 Elsevier Ltd. All rights reserved.

    DOI

  • Buffers to suppress sodium dodecyl sulfate adsorption to polyethylene oxide for protein separation on capillary polymer electrophoresis

    Keiko Sumitomo, Koichi Mayumi, Hiroyuki Minamikawa, Mitsutoshi Masuda, Toru Asahi, Toshimi Shimizu, Kohzo Ito, Yoshinori Yamaguchi

    ELECTROPHORESIS   32 ( 3-4 ) 448 - 454  2011.02  [Refereed]

     View Summary

    Although polyethylene oxide (PEO) offers several advantages as a sieving polymer in SDS capillary polymer electrophoresis (SDS-CPE), solution properties of PEO cause deterioration in the electrophoresis because PEO in solution aggregates itself, degrades into smaller pieces, and forms polymer-micelle complexes with SDS. We examined protein separation on SDS-CPE with PEO as a sieving matrix in four individual buffer solutions: Tris-CHES, Tris-Gly, Tris-Tricine, and Tris-HCl buffers. The solution properties of PEO as a sieving matrix in those buffers were examined by dynamic light scattering (DLS) and by surface tension. Preferential SDS adsorption onto PEO disturbed protein-SDS complexation and impaired the protein separation efficiency. Substantial adsorption of SDS to PEO was particularly observed in Tris-Gly buffer. The Tris-CHES buffer prevented SDS from adsorbing onto the PEO. Only Tris-CHES buffer achieved separation of six proteins. This study demonstrated efficient protein separation on SDS-CPE with PEO.

    DOI

  • Buffers to Suppress SDS Adsorption to PEO for Protein Separation on Capillary Polymer Electrophoresis

    K. Sumitomo, K. Mayumi, H. Minamikawa, M. Masuda, T. Asahi, T. Shimizu, K. Ito, Y. Yamaguchi

    Electrophoresis   32   448 - 454  2011.02  [Refereed]

  • Improvement of magnetic intergranular isolation and evaluation of read/write characteristics on SmCo5 perpendicular magnetic thin films

    Toru Asahi, Isao Koizumi, Yuko Egawa, Masahiro Yoshino, Atsushi Sugiyama, Jiro Hokkyo, Takanori Kiya, Jun Ariake, Kazuhiro Ouchi, Tetsuya Osaka

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS   322 ( 23 ) 3784 - 3788  2010.12  [Refereed]

     View Summary

    SmCo5 alloy is a promising candidate for ultra-high-density perpendicular magnetic recording (PMR) media because of its high uniaxial magnetocrystalline anisotropy K-u of more than 1.1 x 10(8) erg/cm(3). Previously, we successfully achieved high K-u in a sputter-deposited SmCo5 thin film by introducing a Cu/Ti dual underlayer. However, in order to apply the SmCo5 films to practical PMR media, it is necessary to decrease medium noise. A granulated magnetic film comprising of small and magnetically decoupled grains is effective in reducing the medium noise. In this paper, we have proposed a new granular film that is fabricated by partial thermodiffusion of Cu between the Sm-Co continuous layer and the Cu underlayer, which is granulated using compositional segregation caused by the addition of Ta2O5. We have analyzed the magnetic properties, magnetic domain size, and magnetization reversal process of the proposed SmCo5 film. The magnetic domain size decreased and the magnetization reversal process changed from the magnetic-wall-motion mode to a coherent rotation mode to some extent on isolation of magnetic grains. The read/write characteristics of granulated SmCo5 double-layered media were also evaluated. The medium noise decreased and the signal-to-noise ratio increased for the granulated double-layered (PMR) medium. (C) 2010 Elsevier B.V. All rights reserved.

    DOI

  • Improvement of Magnetic Properties and Evaluation of Read/Write Characteristics on Granular SmCo5 Perpendicular Magnetic Thin Films

    T. Asahi, I. Koizumi, Y. Egawa, M. Yoshino, A. Sugiyama, J. Hokkyo, T. Kiya, J. Ariake, K. Ouchi, T. Osaka

    Journal of Magnetism and Magnetic Materials   322   3784 - 3788  2010.12  [Refereed]

  • Fabrication of SmCo5-CrTa Granular Films

    A. Sugiyama, I. Koizumi, Y. Egawa, M. Yoshino, J. Hokkyo, T. Asahi, T. Osaka

    IEEE TRANSACTIONS ON MAGNETICS   46 ( 6 ) 1699 - 1701  2010.06  [Refereed]

     View Summary

    A Sm-Co-CrTa granular layer between a Sm-Co continuous layer and a Cu underlayer was prepared in order to improve magnetic properties and magnetic reversal process of Sm-Co perpendicular film. A phase of CrTa alloy in Sm-Co-CrTa layer has a role in control of Cu partial interlayer diffusion between the Sm-Co continuous layer and the Cu underlayer. The Cu diffusion provides the partial crystallization of SmCo5 in the continuous layer. Although the perpendicular coercivity of films decreased slightly by introducing the CrTa alloy into Sm-Co layer, the magnetic intergranular exchange interaction in the films was drastically improved. Size of average magnetic cluster became smaller and magnetization reversal process was changed from a wall-motion to a coherent rotation for increasing the thickness ratio of Sm-Co-CrTa/Sm-Co layers. We confirmed that an addition of Sm-Co-CrTa layer is effective to reduce the intergranular exchange interaction in Sm-Co perpendicular films without deterioration of perpendicular magnetic anisotropy.

    DOI

  • Evaluation of stability difference between asymmetric homochiral dimer in (S)-thalidomide crystal and symmetric heterochiral dimer in (RS)-thalidomide crystal

    Toshiya Suzuki, Masahito Tanaka, Motoo Shiro, Norio Shibata, Tetsuya Osaka, Toru Asahi

    PHASE TRANSITIONS   83 ( 3 ) 223 - 234  2010  [Refereed]

     View Summary

    This article discusses differences in physicochemical properties such as solubility and melting point between (S)-thalidomide and (RS)-thalidomide based on crystal structures determined by X-ray diffraction experiments. Investigation of such differences is of great importance because thalidomide has attracted considerable attention again due to its wide-range bioactivity for intractable diseases. In this article, structures of hydrogen-bonded rings were compared between asymmetric homochiral dimers in (S)-thalidomide crystal and symmetric heterochiral dimers in (RS)-thalidomide crystal. The heterochiral dimer was evaluated to be more stable than the homochiral dimer by the energy calculations for hydrogen-bonded rings in those dimers. These results indicate that differences in physicochemical properties between enantiomeric and racemic thalidomides originate from the difference of structural stability between homochiral and heterochiral dimers.

    DOI

  • Effects of CdSe/ZnS quantum dots covered multi-walled carbon nanotubes on murine embryonicstem cells

    Daxiang Cui, Hong Zhang, Jie Sheng, Zheng Wang, Asahi Toru, Rong He, Osaka Tetsuya, Feng Gao, Hoon Sung Cho, Chris Huth, Hengyao Hu, Giovanni M. Pauletti, Donglu Shi

    Nano Biomedicine and Engineering   2 ( 4 ) 236 - 244  2010

     View Summary

    Stem cells nanotechnology has emerged as a new exciting area, and holds great potential for research and development of stem cells as novel therapeutic platforms for genetic, traumatic, and degenerative medicine. Vital to the success of this technology are approaches that reproducibly facilitate in vivo cell tracking, expansion, differentiation, and transplantation. Herein we reported the effects of CdSe/ZnS quantum dots covered multi-walled carbon nanotubes (FMNTs) on mice embryonic stem cell line CCE cells. The FMNTs were prepared by plasma surface treatment and characterized by high resolution transmission electron microscopy (HR-TEM), and incubated with murine ES CCE cells for 1 to 28 day.These ES cells were observed by confocal laser scanning microscopy, and were analyzed by real time reverse transcription-polymerase chain reaction (RTPCR), flow cytometry (FCM) and MTT method. Results showed that prepared FMNTs exhibited green fluorescent signal, could enter into ES cells in time-dependent means, more than 20 μg ml-1 FMNTs induced ES cells become smaller and smaller as the incubation time increased, and inhibited cell growth in dose-and time-dependent means, induced apoptosis of ES cells
    conversely, 5 μg ml-1 FMNTs could markedly stimulate the expression of Sox1 and Hsp27, and inhibit expression of OCT4 in ES cells, FCM analysis showed that differentiation marker Flk-1 exhibited higher expression compared with control ES cells. In conclusion, high dose of FMNTs can inhibit proliferation of ES cells, low dose of FMNTs can improve the differentiation of ES cells, FMNTs can have potential applications in in vivo tracking, imaging and regulation of the proliferation and differentiation of ES cells. © 2010 D. Cui, et al.

    DOI

  • Evaluation of stability difference between asymmetric homochiral dimer in (S)-thalidomide crystal and symmetric heterochiral dimer in (RS)-thalidomide crystal

    Toshiya Suzuki, Masahito Tanaka, Motoo Shiro, Norio Shibata, Tetsuya Osaka, Toru Asahi

    PHASE TRANSITIONS   83 ( 3 ) 223 - 234  2010

     View Summary

    This article discusses differences in physicochemical properties such as solubility and melting point between (S)-thalidomide and (RS)-thalidomide based on crystal structures determined by X-ray diffraction experiments. Investigation of such differences is of great importance because thalidomide has attracted considerable attention again due to its wide-range bioactivity for intractable diseases. In this article, structures of hydrogen-bonded rings were compared between asymmetric homochiral dimers in (S)-thalidomide crystal and symmetric heterochiral dimers in (RS)-thalidomide crystal. The heterochiral dimer was evaluated to be more stable than the homochiral dimer by the energy calculations for hydrogen-bonded rings in those dimers. These results indicate that differences in physicochemical properties between enantiomeric and racemic thalidomides originate from the difference of structural stability between homochiral and heterochiral dimers.

    DOI

  • Single walled carbon nanotubes based regulation of proliferation and differentiation of mouse embryonic stem cells

    Daxiang Cui, Z. Wang, H. Zhang, J. Ruan, C. C. Bao, H. Yang, Asahi Toru, H. Song, K. Wang

    ECS Transactions   19 ( 13 ) 63 - 67  2009

     View Summary

    Carbon nanotubes'bio-effects have become a hotspot. In recent years, my group and collaborators try to use single walled carbon nanotubes(SWCNTs) as drug delivery system to regulate proliferation and differentiation of mouse stem cells. We observed that low dose of SWCNTs stimulate stem cells'proliferation and differentiation, higher dose of SWCNTs improve stem cells' apoptosis. Y-27632, a selective inhibitor of p160 Rho-associated coiled-coil kinase, can conjugate with SWCNTs and form the nanocomposites, which markedly inhibit the apoptosis of mouse stem cells, improve the proliferation and differentiation of stem cells. The potential mechanism of effects of Y-27632-SWCNT composites on stem cells is also dicussed. Our primary results suggest that special enzyme modified SWCNTs can be used to regulate proliferation and differentiation of stem cells, which has potential application in stem cells-based therapy. ©The Electrochemical Society.

    DOI

  • Self-Assembly of Quantum Dots and Carbon Nanotubes for Ultrasensitive DNA and Antigen Detection

    Daxiang Cui, Bifeng Pan, Hong Zhang, Feng Gao, Rina Wu, Jingping Wang, Rong He, Toru Asahi

    ANALYTICAL CHEMISTRY   80 ( 21 ) 7996 - 8001  2008.11

     View Summary

    A highly selective, ultrasensitive, fluorescence detection method for DNA and antigen based on self-assembly of multiwalled carbon nanotubes (CNTs) and CdSe quantum dots (QDs) via oligonucleotide hybridization is reported. Mercaptoalkyloligonucleotide molecules bind to the quantum dots, while amineoalkyloligonucleotides bind to CNTs with -COCl surface groups. QDs and CNTs further assemble into nanohybrids through DNA hybridization in the presence of target complementary oligonucleotides. The method is achieved with good repeatability with the detection limit of 0.2 pM DNA molecules and 0.01 nM antigen molecules. This novel detection system can also be used for multicomponent detection and antigen-antibody immunoreaction. The novel system has great potential in applications such as ultrasensitive pathogen DNA or antigen or antibody detection, molecular imaging, and photoelectrical biosensors.

    DOI

  • Improvement of magnetic properties and read/write characteristics in SmCo(5) perpendicular thin films

    Toru Asahi, Isao Koizumi, Yuta Kikuchi, Masahiro Yoshino, Atsushi Sugiyama, Jiro Hokkyo, Tetsuya Osaka

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS   320 ( 22 ) 3075 - 3078  2008.11  [Refereed]

     View Summary

    An SmCo(5) alloy is a promising candidate for ultra-high density magnetic recording media because of its strong uniaxial magnetocrystalline anisotropy, whose constant, K(u), is more than 1.1 x 10(8) erg/cm(3). Recently, we successfully obtained high perpendicular magnetic anisotropy for a sputter-deposited SmCo(5) thin film by introducing a Cu/Ti dual underlayer. However, it is necessary to improve magnetic properties and read/write (R/W) characteristics for applying SmCo(5) thin films to perpendicular magnetic recording media. In this study, we focused on reduction of magnetic domain size and change of a magnetization reversal process of SmCo(5) perpendicular magnetic thin. films by introducing carbon (C) atoms into the constituent Cu underlayer. The magnetic domain size became small and the ratio of coercivity (H(c)) against magnetic anisotropy (H(k)) which is an index of the magnetization reversal process was increased by adding C atoms. We also evaluated the R/W characteristics of SmCo(5) double-layered media including C atoms. The medium noise was decreased and signal-to-noise ratio increased by introducing the C. The addition of C into the Cu underlayer is effective for changing the magnetization reversal process, reducing medium noise and increasing SNR. (C) 2008 Published by Elsevier B. V.

    DOI

  • Magnetic circular dichroism of [Co/Pd] and [CoB/Pd] multilayered films

    A. Agui, A. Asahi, J. Sayama, M. Mizumaki, M. Tanaka, T. Osaka

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS   320 ( 22 ) 3015 - 3018  2008.11  [Refereed]

     View Summary

    Magnetic circular dichroism (MCD) and X-ray absorption spectra (XAS) at the Co L(2,3)-edge of [Co/Pd](20) and [CoB/Pd](20) multilayered films, which were fabricated at 260 degrees C with different magnetic layer thicknesses (delta), have been measured. The lineshapes of XAS-MCD show that the electronic state of Co 3d of the films hardly changes even when sputtered at higher temperatures. The expectation values of orbital and spin angular momentum (&lt; L(z)&gt; and &lt; S(z)&gt;) are estimated using the sum rule, and it is found that &lt; L(z)&gt;/&lt; S(z)&gt; in delta&lt;0.5 nm is larger than that in delta&gt;0.5 nm. (C) 2008 Elsevier B. V. All rights reserved.

    DOI

  • Effect of Growth Temperature on the Shape and Crystallinity of Chemically Produced FePt Nanoparticles

    T. Hachisu, T. Yotsumoto, A. Sugiyama, H. Iida, T. Nakanishi, T. Asahi, T. Osaka

    Chemistry Letters   37   840 - 841  2008.08

  • Existence and Origin of Compensation Layer Thickness in Tb20Co80/Pd Multilayered Films

    M. Tanaka, T. Asahi, A. Agui, M. Mizumaki, J. Sayama, T. Osaka

    Journal of Physics D:Applied Physics   41   55003 - 55006  2008  [Refereed]

  • Effect of Surface Coverage of Gold(111) Electrode with Cysteine on the Chiral Discrimination of DOPA

    M. Matsunaga, T. Nakanishi, T. Asahi, T. Osaka

    Chirality   19   S36 - S39  2007.05  [Refereed]

  • Highly enantioselective discrimination of amino acids using copper deposition on a gold electrode modified with homocysteine monolayer

    Mariko Matsunaga, Takuya Nakanishi, Toru Asahi, Tetsuya Osaka

    ELECTROCHEMISTRY COMMUNICATIONS   9 ( 4 ) 725 - 728  2007.04  [Refereed]

     View Summary

    An extremely enhanced enantioselectivity was achieved for the detection of enantiomers of alanine (Ala), leucine (Leu), and 3,4-dihydroxyphenylalanine (DOPA) based on the voltammograms for the deposition of Cu from Cu complexes of the amino acids at an Au electrode modified with a self-assembled monolayer (SAM) Of L-homocysteine (Hcy). The enantioselective current density peak for the Cu deposition was found to change with increasing number of potential cycles after the addition of Cu(II), and the highest enantioselectivity was observed immediately after the addition of Cu(II). Besides, enantio selectivity was not observed with proline, whose five-membered ring contains the nitrogen atom of a secondary amino group, while some amino acids with a primary amine group such as Ala, Leu, and DOPA exhibited enantioselectivity. These results suggest that the chiral ligand exchange reaction at the L-Hcy SAM-modified Au electrode, namely, the enantioselective formation of diastereomeric complexes of Cu(II) with target enantiomers and L-Hcy self-assembled on the Au electrode, plays an important role in the chiral discrimination based on the Cu deposition. (c) 2006 Elsevier B.V. All rights reserved.

    DOI

  • Sputter-deposited SmCo5 thin films with perpendicular magnetic anisotropy for high density magnetic recording media

    J. Sayama, Y. Yamashita, T. Asahi, T. Osaka

    ECS Transactions   3 ( 25 ) 307 - 313  2007

     View Summary

    Sputter-deposited SmCos thin films exhibiting high perpendicular magnetic anisotropy were studied for materializing ultra high density magnetic recording. This study put emphasis on the fabrication of SmCos double-layered perpendicular magnetic recording media. A double-layered medium with a Ru buffer layer introduced between a Cu/Ti intermediate layer and a Co-Zr-Nb soft magnetic underlayer exhibited high perpendicular magnetic anisotropy, whereas that without the Ru buffer layer did not. Auger electron spectroscopy revealed that the Ru buffer layer inhibited unfavorable interdiffusion between the Cu/Ti intermediate layer and the Co-Zr-Nb soft magnetic underlayer. In addition, the readwrite characteristics of the SmCos double-layered perpendicular magnetic recording media were evaluated for the first time. copyright The Electrochemical Society.

    DOI

  • Enantioselectivity of redox reaction of DOPA at the gold electrode modified with a self-assembled monolayer of homocysteine

    Takuya Nakanishi, Mariko Matsunaga, Makoto Nagasaka, Toru Asahi, Tetsuya Osaka

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   128 ( 41 ) 13322 - 13323  2006.10  [Refereed]

    DOI

  • Soft X-ray Absorption Spectroscopy and Magnetic Circular Dichroism Study of Electroless-deposited CoNiFe Ternary Alloy Soft Magnetic Film

    M. Tanaka, N. Nakamura, T. Asahi, T. Tsumori, A. Agui, M. Mizumaki, T. Osaka

    Physica Status Solidi   3   2783 - 2786  2006.09  [Refereed]

  • Electrochemical Formation of Intermediate Layer for Co/Pd Multilayered Media

    J. Kawaji, K. Kimura, T. Asahi, T. Homma, T. Osaka

    Journal of Magnetism and Magnetic Materials   303   128 - 132  2006.08  [Refereed]

  • Crystalline of Leucine on a self-assembled Monolayer with Covalently Attached Enantiomeric Leucine Molecules

    T. Nakanishi, N. Banno, M. Matsunaga, T. Asahi, T. Osaka

    Colloids and Surfaces A: Physicochemical and Engineering Aspects   284   270 - 275  2006.08  [Refereed]

  • Study on N-2-added and B-doped effect in Co/Pd multilayered films using soft x-ray absorption and magnetic circular dichroism

    A. Agui, T. Asahi, J. Sayama, J. Kawaji, M. Mizumaki, M. Tanaka, T. Osaka

    JOURNAL OF PHYSICS D-APPLIED PHYSICS   39 ( 14 ) 2881 - 2885  2006.07  [Refereed]

     View Summary

    The soft x-ray absorption and magnetic circular dichroism spectra at the Co L-2,L-3-edges of [Co/Pd](20) and [CoB/Pd](20) multilayered films, which were sputter- deposited in Ar gas containing N-2 at room temperature, were measured to investigate the electronic and spin states of the films. The macroscopic magnetic properties, such as coercivity and saturation magnetization, and microstructural properties, such as grain size and preferred orientation, were markedly changed for the [Co/Pd](20) film by the B doping and N-2 addition. The B doping and/or the addition of N-2 gas caused appreciable changes not only in macroscopic magnetic properties but also in microscopic properties, such as the spin angular momentum and orbital angular momentum, throughout the multilayered film. On the other hand, a new spectral feature at the high energy side of the Co L-3-edge peak in x-ray absorption spectra was found in only the films with N-2 added. Thus, the microscopic properties, such as electronic and spin states, of the Co 3d electronic state for the [Co/Pd](20) and [CoB/Pd](20) films were changed by only the sputtering process with additive N-2 gas.

    DOI

  • Origin of perpendicular magnetic anisotropy of SMCo5 thin films with Cu underlayer

    J Sayama, K Mizutani, T Asahi, J Ariake, K Ouchi, T Osaka

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS   301 ( 1 ) 271 - 278  2006.06  [Refereed]

     View Summary

    Effects of the Cu underlayer thickness and the addition Of Cu to a Sm-Co layer on magnetic properties and microstructure Of SmCo5 thin films exhibiting perpendicular magnetic anisotropy were studied. The origin of the perpendicular magnetic anisotropy was discussed from these experimental results. A thick Cu underlayer of more than 100 nm brought about high perpendicular magnetic anisotropy leading to the squareness ratio equal to unity. The Cu addition enhanced the perpendicular magnetic anisotropy and reduced the Cu underlayer thickness required to obtain the squareness ratio of unity. X-ray diffractometry showed that the crystalline orientation of the Sm-Co layer did not correlate with that of the Cu underlayer. Auger electron spectroscopy revealed that Cu atoms were diffused up to the Sm-Co layer from the Cu underlayer. From the results, Cu atoms existing in the Sm-Co layer were suggested to be strongly related with an appearance of the perpendicular magnetic anisotropy by introducing the Cu underlayer. (c) 2005 Elsevier B.V. All rights reserved.

    DOI

  • Effect of substrate morphology on the crystallization of leucine on gold surface modified with a self-assembled monolayer

    Tetsuya Osaka, Mariko Matsunaga, Takuya Nakanishi, Toru Asahi, Naoki Banno

    CHEMISTRY LETTERS   35 ( 4 ) 438 - 439  2006.04  [Refereed]

     View Summary

    The effect of the surface morphology of gold-deposited quartz substrate on the enantioselective crystallization of leucine was investigated by using quartz crystal microbalance (QCM) and X-ray diffraction methods. The gold substrate was modified with a self-assembled monolayer with covalently attached D-leucine molecules. For a rough surface with root-mean-square (RMS) roughness of 17 nm, the QCM measurement showed a continuous decrease in frequency, while for a smooth surface with RMS roughness of 2 nm, essentially no change in frequency was observed. Nevertheless, leucine crystals with high crystallinity were clearly formed on the smooth surface.

    DOI

  • Incident angle dependence of MCD at the Dy M-5-edge of perpendicular magnetic DyxCo100-x films

    A Agui, M Mizumaki, T Asahi, J Sayama, K Matsumoto, T Morikawa, T Matsushita, T Osaka, Y Miura

    JOURNAL OF ALLOYS AND COMPOUNDS   408   741 - 745  2006.02  [Refereed]

     View Summary

    X-ray absorption and magnetic circular dichroism spectra (XAS-MCD) of the Dy M-4,M-5-edges of DyxCo100-x (x=15-33) thin films are measured. The advantage of element and orbital selectivity in the XAS-MCD measurements enables us to directly observe the magnetic moments of specified elements. The MCD intensity at the Dy M-5-edge is maximum when the incident X-ray is normal to the surface and the incident angle dependence of the MCD intensity shows a sine curve. That gives us information about the angular distribution of the Dy magnetic moments with respect to the total magnetization direction and the opening angle of the cone. Applying the sum rule, the expectation value of orbital magnetic moment was estimated. The half opening angle of the random distribution of the moments were estimated and it was found that the angle has its minimum value around x=20. (c) 2005 Elsevier B.V. All rights reserved.

    DOI

  • Magnetic Properties and Domain Structure of SmCo5 Perpendicular Magnetization Films Prepared by Using a UHV Sputtering System

    J. Sayama, T. Asahi, Y. Yamashita, J. Ariake, K. Ouchi, T. Osaka

    Journal of the Magnetics Society of Japan   30   423 - 428  2006

  • SmC0(5)-Based thin films with high magnetic Anisotropy for perpendicular magnetic recording

    J Sayama, K Mizutani, Y Yamashita, T Asahi, T Osaka

    IEEE TRANSACTIONS ON MAGNETICS   41 ( 10 ) 3133 - 3135  2005.10  [Refereed]

     View Summary

    An investigation was carried out on the effects of the addition of Cu and the thickness of the SmCo5-based thin film with perpendicular magnetic anisotropy upon its magnetic properties, with the aim of reducing the Cu/Ti underlayer thickness. As a result, the Cu/Ti underlayer thickness necessary to obtain the squareness ratio of unity was successfully reduced from 125 to 50 nm. Moreover, for the SmCo5 double-layered perpendicular magnetic recording media with a CoZrNb soft magnetic underlayer, the Cu/Ti underlayer thickness was further reduced to 35 nm. However, the magnetic cluster size and the values of coercivity and saturation field of the SmCo5 media were found to be too large. Thus, we recognized the need for adjusting the cluster size and the magnetic properties to appropriate values, and also the need for investigating the possibility of using this material as patterned media or thermally assisted recording media.

  • Optical Activity Induced by Helical Arrangements of Tryptamine and 4-Chlorobenzoic Acid in Their Cocrystal

    H. Koshima, M. Nagano, T. Asahi

    Journal of American Chemical Society   127   2455 - 2463  2005.04

  • Microstructure of a Co/Pd multilayered perpendicular recording medium with Pd seeds prepared by electrochemical process

    M Tanaka, J Kawaji, K Kimura, T Asahi, T Homma, S Matsunuma, T Osaka

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS   287   188 - 192  2005.02  [Refereed]

     View Summary

    Effects of the Pd seeds formed by an electrochemical process on the microstructures of Co/Pd multilayered perpendicular recording media were investigated. By immersing a CoZrNb soft magnetic underlayer (SUL) into PdCl2 aqueous solution, island-like Pd clusters were deposited on the SUL, resulting from the electrochemical substitution reaction. Transmission electron microscopic observations revealed that the columnar Co/Pd multilayered grains with clear boundaries grew on the SUL with the Pd clusters. The clear grain boundaries, where the densities of Co and Pd elements were low, were thought to cause the magnetic exchange decoupling between the Co/Pd grains, leading to an increase of perpendicular coercivity and a decrease of magnetic cluster size of Co/Pd multilayered film. Consequently, lower medium noise was obtained for the Co/Pd multilayered medium with the Pd clusters than for that with a sputter-deposited Pd seedlayer. From these investigations, it was clarified that the SUL surface with Pd clusters provided the effective nucleation sites for a well-defined Co/Pd multilayered grain growth. (C) 2004 Elsevier B.V. All rights reserved.

    DOI

  • Magnetic properties and microstructure of SmCo5 thin film with perpendicular magnetic anisotropy

    J Sayama, K Mizutani, T Asahi, J Ariake, K Ouchi, S Matsunuma, T Osaka

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS   287   239 - 244  2005.02  [Refereed]

     View Summary

    SmCo5 thin films with Cu seedlayer exhibiting perpendicular magnetic anisotropy were studied. The perpendicular magnetic anisotropy was enhanced using the Sm-Co layer formed by laminating Co and Sm sub-layers alternately. The Co/Sm laminate structure promoted the crystallization Of SmCo5 and the preferred orientation of its c-axis. The perpendicular magnetic anisotropy was further improved by suppressing the surface roughness of the Cu seedlayer. The SmCo5 thin film prepared in this study possesses an adequate corrosion resistance when judged by an electrochemical analysis. (C) 2004 Elsevier B.V. All rights reserved.

    DOI

  • Electroless-deposited soft magnetic underlayer on silicon disk substrate for double-layered perpendicular magnetic recording media

    T Osaka, T Asahi, T Yokoshima, J Kawaji

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS   287   292 - 297  2005.02  [Refereed]

     View Summary

    A novel fabrication process of a soft magnetic underlayer (SUL) for a double-layered perpendicular magnetic recording medium was presented. The CoNiFeB SUL was deposited on a silicon disk substrate using an electroless deposition. The Ni seed layer for the electroless deposition was prepared by an electrochemical process. The surface of the deposited SUL was subjected to a chemical mechanical polishing to be flattened, and R-a value of the SUL was less than 0.4 nm. A magnetic domain structure greatly depended on the electroless deposition condition. Particularly, the control of an agitation speed during electroless deposition is much effective for the suppression of distinct domain walls appearing in CoNiFeB underlayers. (C) 2004 Published by Elsevier B.V.

    DOI

  • Effect of N-2 additive gas during sputtering on magnetic properties and microstructure of CoB/Pd multilayered media

    T Asahi, M Tanaka, J Sayama, J Kawaji, S Matsunuma, T Osaka

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS   287   199 - 203  2005.02  [Refereed]

     View Summary

    Effects of N-2 additive gas and/or substrate heating during the sputtering of [CoB/Pd](20) multilayered films on the magnetic properties and microstructure were investigated. The [CoB/Pd](20) film fabricated at 20degreesC by adding N-2 gas during sputtering possessed the finest grain size and the smallest magnetic cluster size among media fabricated in this study although the film sputter-deposited at 260 degreesC by adding N-2 gas exhibited the weakest intergranular exchange coupling. It was revealed that the double-layered perpendicular magnetic recording medium that consisted of the [CoB/Pd](20) film fabricated at 20degreesC by adding N-2 gas exhibited the highest signal-to-noise ratio in the read write characteristics. (C) 2004 Elsevier B.V. All rights reserved.

    DOI

  • Electroless Deposition of Soft Magnetic Underlayer for a Double-layered Perpendicular Recording Media

    A. Sugiyama, T. Asahi, K. Adachi, M. Sakagami, J. Kawaji, M. Yoshino, T. Osaka, T. Tsumori

    IEICE Technical Report   MR2004-48 ( 1 ) 15 - 20  2005

    CiNii

  • Thin films of SmCo5 with very high perpendicular magnetic anisotropy

    J Sayama, K Mizutani, T Asahi, T Osaka

    APPLIED PHYSICS LETTERS   85 ( 23 ) 5640 - 5642  2004.12  [Refereed]

     View Summary

    Thin films of SmCo5 with extraordinarily high perpendicular magnetic anisotropy were prepared by introducing a Cu/Ti dual underlayer and controlling the substrate temperature during the sputter deposition. Under optimized conditions, the magnetic anisotropy constant reached 4.0x10(7) erg/cm(3), and the coercivity and the remanence ratio in the direction perpendicular to the film surface were 12.0 kOe and unity, respectively. The high perpendicular magnetic anisotropy is attributed to the high degree of preferred orientation of the c axis; the full width at half maximum in the rocking curve of SmCo5(002) reflection was 3.1degrees. (C) 2004 American Institute of Physics.

    DOI

  • Formation of Pd nanocluster seeds by electrochemical process for control of magnetic properties in Co/Pd multilayered film

    J Kawaji, M Tanaka, K Kimura, T Asahi, T Homma, T Osaka

    IEEE TRANSACTIONS ON MAGNETICS   40 ( 4 ) 2473 - 2475  2004.07  [Refereed]

     View Summary

    Pd cluster seeds for a double-layered perpendicular magnetic recording medium composed of a Co/Pd multilayered film and a CoZrNb soft magnetic underlayer (SUL) were fabricated with an electrochemical treatment. By immersing the SUL into an aqueous PdCl2 solution, the substitution of Pd for Co at the surface of the SUL took place, which was caused by the difference in electrochemical redox potential between Pd and Co. Uniformly distributed Pd clusters with 8 nm in diameter were successfully formed with the treatment for the optimized duration. Use of the Pd clusters as the seeds for deposition of the Co/Pd multilayered film increased the perpendicular coercivity and reduced the size of magnetic cluster of the film. These results suggested that the Pd cluster seeds led to the formation of magnetically isolated Co/Pd multilayered grains, improving the magnetic properties of Co/Pd multilayered film.

    DOI

  • Soft x-ray magnetic circular dichroism study of [Co/Pd] multilayered perpendicular magnetic films

    A Agui, M Mizumaki, T Matsushita, T Asahi, J Kawaji, J Sayama, T Osaka

    JOURNAL OF APPLIED PHYSICS   95 ( 12 ) 7825 - 7831  2004.06  [Refereed]

     View Summary

    The electronic and spin states of [Co/Pd] multilayered perpendicular magnetization films with various seedlayers have been investigated by means of soft x-ray absorption and magnetic circular dichroism spectroscopy at the Co L-2,L-3-edges. The expectation values of the orbital angular momentum &lt;L-z&gt; and the spin angular momentum &lt;S-z&gt; of Co atom in the [Co/Pd] multilayered film were estimated using the sum rule. It was found that the seedlayer changes macroscopic magnetic properties of the [Co/Pd] multilayered film without affecting the electronic and spin states of the upper layers of Co. (C) 2004 American Institute of Physics.

    DOI

  • Microstructure and magnetic properties of a Co/Pd multilayer on a controlled Pd/Si seed layer for double-layered perpendicular magnetic recording media

    J Kawaji, T Asahi, H Hashimoto, J Hokkyo, T Osaka, S Matsunuma, G Safran, J Ariake, K Ouchi

    JOURNAL OF APPLIED PHYSICS   95 ( 12 ) 8023 - 8029  2004.06  [Refereed]

     View Summary

    A 10 nm Pd/Si dual thin film was developed as a seed layer for a Co/Pd multilayer in double-layered perpendicular magnetic recording media. The Pd/Si seed layer, sputter deposited under Ar sputtering gas containing N-2 and postannealed at 400 degreesC, markedly reduced intergranular exchange coupling of the Co/Pd multilayered film, resulting in a decrease in both the slope parameter, defined as 4pi(dM/dH)(H=Hc), and the magnetic cluster size. Consequently, medium noise was essentially reduced, thereby improving the signal-to-noise ratio of the Co/Pd recording media on a CoZrNb soft magnetic underlayer. The addition of N-2 gas effectively decreased the grain size of Pd in the seed layer. A Pd/Si seed layer prepared with both processes exhibited a granular structure of fine Pd-rich grains surrounded by a Si-rich amorphous region, which provided nucleation sites for the growth of well-separated Co/Pd multilayered grains. (C) 2004 American Institute of Physics.

    DOI

  • Chiral Discrimination Between Thalidomide Enantiomers Using a Solid Surface With Two-Dimensional Chirality

    T. Nakanishi, N. Yamakawa, T. Asahi, N. Shibata, B. Ohtani, T. Osaka

    Chirality   16   S36 - S39  2004.06  [Refereed]

  • Application of Soft X-ray Magnetic Circular Dichroism Spectroscopy to the Investigation of [Co/Pd] Multilayered Perpendicular Magnetic Recording Media with Various Seedlayers

    A. Agui, M. Mizumaki, T. Matsushita, T. Asahi, J. Kawaji, J. Sayama, T. Osaka

    Journal of Applied Physics   95   7825 - 7831  2004.06

  • Optimization of the Thickness Ratio of Pd/Si Intermediate Layer in a Co/Pd Multilayer Perpendicular Magnetic Recording Media

    J. Kawaji, H. Hashimoto, T. Asahi, J. Hokkyo, T. Osaka

    Transactions of the Magnetics Society of Japan   4   78 - 84  2004

  • MCD Measurement at the Tb M4,5-edges of Tb17FexCo(83-x) Perpendicular Magnetization Films

    A. Agui, M. Mizumaki, T. Asahi, J. Sayama, K. Matsumoto, T. Morikawa, T. Nakatani, T. Matsushita, T. Osaka, Y. Miura

    Transactions of the Magnetics Society of Japan   4   326 - 329  2004

  • Newly developed SmCo5 thin film with perpendicular magnetic anisotropy

    J. Sayama, T. Asahi, K. Mizutani, T. Osaka

    Journal of Physics D: Applied Physics   37   1 - 4  2004  [Refereed]

  • Magnetic Properties of SmCo5 Perpendicular. Magnetization Film with Cu Seedlayer

    J. Sayama, K. Mizutani, T. Asahi, T. Osaka

    IEICE Technical Report   MR2004-8   7 - 11  2004

  • Enantioselective Crystal Growth of Leucine on a Self-Assembled Monolayer with Covalently Attached Leucine Monolayers

    N. Banno, T. Nakanishi, M. Matsunaga, T. Asahi, T. Osaka

    Journal of American Chemical Society   126   428 - 429  2004  [Refereed]

  • Measurement of Circular Dichroism of Ferroelectric Fresnoite Ba2Si2TiO8

    T. Asahi, T. Osaka, J. Kobayashi

    Proceedings of SPIE   5218   223 - 232  2003  [Refereed]

  • Microstructure and magnetic properties of Co/Pd multilayered thin films with C or Si seedlayer

    T Onoue, T Asahi, K Kuramochi, J Kawaji, T Osaka, J Ariake, K Ouchi, G Safran, N Yaguchi

    JOURNAL OF APPLIED PHYSICS   92 ( 8 ) 4545 - 4552  2002.10  [Refereed]

     View Summary

    Microstructure and magnetic properties of sputter deposited Co/Pd multilayered perpendicular magnetization films with amorphous C or Si seedlayer were investigated. The angstrom scale surface roughness of the seedlayer causes fine crystal grains to form in the Co/Pd multilayer and to decrease the extent of intergranular exchange coupling, while it obstructs the formation of a regular interface between Co and Pd layers. The Si seedlayer, which exhibits a surface roughness lower than the C seedlayer, yields Co/Pd multilayered films with the lowest intergranular exchange coupling and the highest coercivity. The improvement in magnetic properties of the Co/Pd film with Si seedlayer is attributable mainly to the formation of Pd2Si at the interface between the Co/Pd layer and the Si seedlayer. The Pd2Si provides suitable nucleation sites for the grain growth of Co/Pd multilayered film that can be utilized as a perpendicular magnetic recording medium. (C) 2002 American Institute of Physics.

    DOI

  • Enhancement of magnetic properties of Co/Pd multilayered perpendicular magnetic recording media by using Pd/Si dual seedlayer

    J Kawaji, T Asahi, T Onoue, J Sayama, J Hokkyo, T Osaka, K Ouchi

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS   251 ( 2 ) 220 - 228  2002.10  [Refereed]

     View Summary

    Effects of the introduction of a Pd/Si dual seedlayer on the microcrystalline structure and magnetic properties of [Co/Pd](n) multilayered perpendicular magnetic recording media were investigated. The Pd/Si dual seedlayer was composed of a Pd upper seedlayer and a Si under seedlayer. The Pd upper seedlayer with a thickness of up to 10 nm markedly increased the coercivity of [Co/Pd](n) multilayered media in the direction perpendicular to the film surface. The highest coercivity of 7.8kOe was obtained for the [Co/Pd](10) medium with a Pd (10nm)/Si (100nm) dual seedlayer. The Pd upper seedlayer not only facilitated the formation of regular interfaces between the Co and Pd layers, but also reduced the thickness of the deteriorated initial layer in the [Co/Pd](n) multilayer, resulting in enhancement of the magnetic anisotropy field. The [Co/Pd](n) multilayered medium with the Pd/Si dual seedlayer exhibited weak intergranular exchange coupling between [Co/Pd](n) grains, which led to excellent read-write characteristics. (C) 2002 Elsevier Science B.V. All rights reserved.

  • Enantioselective adsorption of phenylalanine onto self-assembled monolayers of 1,1 '-binaphthalene-2,2 '-dithiol on gold

    T Nakanishi, N Yamakawa, T Asahi, T Osaka, B Ohtani, K Uosaki

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   124 ( 5 ) 740 - 741  2002.02  [Refereed]

    DOI

  • Thermal Deposition High-Resolution Mass Spectroscopy of mixed Self-Assmbled Monolayers on Gold

    T. Shibue, T. Nakanishi, T. Matsuda, T. Asahi, T. Osaka

    Langmuir   18   1528 - 1534  2002  [Refereed]

  • Enantioselective adsorption of phenylalanine onto self-assembled monolayers of 1,1 '-binaphthalene-2,2 '-dithiol on gold

    T. Nakanishi, N. Yamakawa, T. Asahi, T. Osaka, B. Ohtani, K. Uosaki

    Journal of American Chemical Society   124   740 - 741  2002

  • Relationship between surface energy and preferred orientation of CoCr alloy magnetic thin films deposited on C and TiCr underlayers

    H Okuo, T Onoue, T Asahi, T Osaka

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS   235 ( 1-3 ) 98 - 103  2001.10  [Refereed]

     View Summary

    The relationship between crystallographic grain orientation and the three kinds of surface energy components; dispersion, polar, and hydrogen bonding components, in Co73Cr18Pt6Ta3 perpendicular magnetic recording media with an amorphous C or a Ti90Cr10 underlayer was discussed. Each surface energy component of the thin film was calculated from an extended Fowkes theory by measuring the contact angle of a test liquid on the thin film. The experimental results revealed that the polar component of surface energy of the Co73Cr18Pt6Ta3 magnetization film with the C underlayer affected greatly the Co [001] preferred orientation of the Co73Cr18Pt6Ta3 magnetization film, while the surface energy of the Co73Cr18Pt6Ta3 magnetic layer with the Ti90Cr10 underlayer had little influence on the distribution of it. (C) 2001 Elsevier Science B.V. All rights reserved.

  • Improvement of signal to noise ratio for Co/Pd multilayer perpendicular magnetic recording media by the addition of an underlayer

    T Onoue, T Asahi, K Kuramochi, J Kawaji, T Homma, T Osaka

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS   235 ( 1-3 ) 40 - 44  2001.10  [Refereed]

     View Summary

    Signal and noise characteristics of Co/Pd multilayer perpendicular magnetic recording media are discussed based upon MFM analysis. The noise of the Co/Pd multilayer media is originated mainly from irregularities in the magnetic transition regions, and can be drastically suppressed by increasing the thickness of the carbon underlayer although a large number of reversed magnetic domains between the magnetic transitions still exist. The fine magnetic clusters formed in the medium with a thick carbon underlayer result in clear magnetic transition boundaries of recorded bits in the high recording density region. By examining the profile of the M-H loops. the decrement in the x value, which is defined as the slope of M-H loop at the value of coercivity, improves the signal to noise (S/N) ratio for the Co/Pd multilayer media. (C) 2001 Elsevier Science B.V. All rights reserved.

  • Analysis of microstructures for Co/Pd multilayer perpendicular magnetic recording media with carbon underlayer

    T Asahi, K Kuramochi, J Kawaji, T Onoue, T Osaka, M Saigo

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS   235 ( 1-3 ) 87 - 92  2001.10  [Refereed]

     View Summary

    The effect of amorphous carbon underlayer thickness on the microstructure of the CO/Pd multilayer perpendicular magnetic recording media was investigated. From the magnetic force microscopy observation in the AC-demagnetized state of the Co/Pd multilayer media, the magnetic cluster size was observed to effectively decrease with an increase in carbon underlayer thickness, where the higher coercivity and the higher SIN ratio of the Co/Pd multilayer media were obtained with the thicker underlayer. Furthermore, the distribution of [111] orientation of FCC-Pd became broader, and the grain size decreased with an increase in the carbon underlayer thickness. These effects caused the magnetic exchange decoupling of Co/Pd multilayer media. We suggested that the change of microstructure was directly related to the surface roughness of the amorphous carbon underlayer. (C) 2001 Elsevier Science B.V. All rights reserved.

  • Enantioselective fluorination mediated by cinchona alkaloid derivatives/selectfluor combinations: Reaction scope and structural information for N-fluorocinchona alkaloids

    N Shibata, E Suzuki, T Asahi, M Shiro

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   123 ( 29 ) 7001 - 7009  2001.07  [Refereed]

     View Summary

    Cinchona-alkaloid/Selectfluor combinations efficiently fluorinate a variety of carbonyl compounds in a highly enantioselective manner to furnish chiral alpha -fluorocarbonyl compounds. The DHQB/Selectfluor combination is effective for the enantioselective fluorination of indanones and tetralones 1 in up to 91% ee. The first enantioselective syntheses of chiral derivatizing reagents 3 was accomplished with high ee and in high chemical yields by the DHQDA/Selectfluor combination. 3-Fluorooxindoles 7 were prepared with ee up to 83% using the (DHQ)zAQN/Selectfluor or the (DHQD)(2)PYR/Selectftuor combination. Since the combinations are conveniently prepared in situ from readily available reagents, the present system represents a practical method for enantioselective fluorination. X-ray crystallography and H-1 NMR analyses of the cinchona alkaloids/Selectfluor combination have established that the species that mediate this novel reaction are N-fluoroammonium cinchona alkaloid tetrafluoroborates, which adopt open conformations.

  • CoCrPtTa and Co/Pd perpendicular magnetic recording media with amorphous underlayers

    T Onoue, T Asahi, K Kuramochi, J Kawaji, T Homma, T Osaka

    IEEE TRANSACTIONS ON MAGNETICS   37 ( 4 ) 1592 - 1594  2001.07  [Refereed]

     View Summary

    The effect of amorphous carbon underlayers on magnetic properties and read-write characteristics of Co73Cr18Pt6Ta3 single layer and Co/Pd multilayer perpendicular magnetic recording media were investigated. The increase in H-c and decrease in alpha, defined as 4 pi (dM/dH)(H=Hc), were observed by increasing the underlayer thickness for both Co-73 Cr18Pt6Ta3 and Co/Pd media. The media with a low alpha value, suggesting a decrease in the exchange coupling, exhibited the higher coercivity and the improvement of S/N ratio. In read-write experiments, the improvement of S/N ratio for the Co/Pd media was achieved up to 400 kFRPI or even higher in the recording density by increasing carbon underlayer thickness, while that for the Co73Cr18Pt6Ta3 media was obtained up to ca. 250 kFRPI.

  • Preparation of a Perpendicular/Longitudinal Composite Medium with a Silicon Intermediate Layer

    Y. Morita, T. Onoue, T. Asahi, T. Honma, T. Osaka

    Journal of the Magnetics Society of Japan   25   619 - 622  2001

  • Preparation of Co/Pd Multilayer Perpendicular Magnetic Recording Media with Carbon Under Layer

    T. Asahi, K. Kuramochi, J. kawaji, T. Onoue, T. Osaka

    Journal of the Magnetics Society of Japan   25   575 - 578  2001

  • Changes of Microstructure Versus Film Thickness in CoCrPtTa/NiCr Media

    K. Kurasawa, M. Kawakami, T. Onoue, T. Asahi, T. Osaka

    Journal of the Magnetics Society of Japan   25   623 - 626  2001

  • Analysis for Magnetized State of Perpendicular Magnetic Recording Media Using MFM

    M. Kawakami, T. Onoue, T. Asahi, J. Hokkyo, T. Osaka

    Journal of the Magnetics Society of Japan   25   571 - 574  2001

  • Polarimetry of Electromagnetic Materials

    T. Asahi, T. Osaka, J. Kobayashi

    Proceedings of SPIE   4467   20 - 30  2001  [Refereed]

  • Optical Study of a Phase Transition of Fresnoite

    T. Asahi, T. Osaka, J. Kobayashi, S. C. Abrahams, S. Nanamatsu, M. Kimura

    Physical Review B   63   1 - 13  2001  [Refereed]

  • Effect of Underlayers on Magnetic Properties of a Co/Pd Multilayer Perpendicular Magnetic Recording Medium

    T. Onoue, J. Kawaji, K. Kuramochi, T. Asahi, T. Osaka

    Journal of Magnetism and Magnetic Materials   235   82 - 86  2001  [Refereed]

  • Absolute Configuration of L-(+)589-Tris(Ethylenediamine) Cobalt(III) Triiodide Monohydrate

    R. Matsuki, T. Asahi, H. Asai, M. Shiro

    Acta Crystallographica E   57   1 - 3  2001  [Refereed]

  • CoCrPtTa single layer perpendicular magnetic recording media with carbon underlayer

    T Onoue, A Takizawa, T Asahi, T Osaka

    JOURNAL OF APPLIED PHYSICS   88 ( 11 ) 6645 - 6651  2000.12  [Refereed]

     View Summary

    Sputter-deposited amorphous carbon was applied as an underlayer for a Co73Cr18Pt6Ta3 Single layer perpendicular magnetic recording medium. It is shown that the amorphous carbon underlayer can control the Co [001] preferred orientation of the Co73Cr18Pt6Ta3 magnetic recording layer and that the microcrystalline structure, magnetic properties, and read-write characteristics of Co73Cr18Pt6Ta3 media are greatly dependent on the carbon underlayer thickness. By x-ray diffraction experiments and transmission electron microscopy observations, it was confirmed that the distribution of the c-axis orientation of Co grains becomes broader in the direction perpendicular to the film surface with increasing carbon underlayer thickness. Furthermore, the Co73Cr18Pt6Ta3 medium with a thick carbon underlayer indicated a relatively high perpendicular coercivity of 2800 Oe and an excellent signal to noise ratio in read-write characteristics. (C) 2000 American Institute of Physics. [S0021-8979(00)03324-7].

  • Influence of substrates on magnetic property and crystalline orientation of CoCrTa/TiCr perpendicular magnetic recording medium

    T Asahi, M Ikeda, A Takizawa, T Onoue, T Osaka

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS   212 ( 1-2 ) 293 - 299  2000.03  [Refereed]

     View Summary

    The influence of substrates on magnetic property and crystalline orientation of CoCrTa/TiCr perpendicular magnetic recording medium was investigated using a glass plate and a Si(1 0 0) single crystal. Magnetic measurements revealed that the film sputtered on a Si(1 0 0) substrate possessed a higher perpendicular coercive force than that on glass, where the pretreatment of the Si(1 0 0) substrate by aqueous HF solution effectively improved the magnetic properties. X-ray diffraction analysis of the films indicated that the crystallinity of the TiCr layer formed on the Si(1 0 0) substrate with the HF pretreatment was higher than that on the glass substrate. It was also found that CoCrTa and TiCr layers on the Si(1 0 0) substrate with the KF pretreatment had a narrower distribution of their c-axis orientation than those on glass substrate. The results of X-ray diffraction analysis were consistent with those of the TEM observation for cross-section bright- and dark-field images and the corresponding THEED patterns. These results suggest that the crystalline surface of the Si(1 0 0) substrate with HF pretreatment has the effect of inducing preferred orientation in the TiCr underlayer, which leads to a decrease in distribution of the c-axis orientation of Co grains in the CoCrTa layer, resulting in an increase in the perpendicular coercive force. (C) 2000 Elsevier Science B.V. All rights reserved.

  • Preparation of a Perpendicular/Longitudinal Composite Medium with a Ni-Alloy Longitudinal Magnetic Underlayer

    M. Kawakami, K. Kurasawa, M. Ikeda, T. Onoue, T. Asahi, T. Osaka

    Journal of the Magnetics Society of Japan   24   263 - 266  2000

  • Fabrication of a Single-Layered Perpendicular Magnetic Recording Medium with a Ge Underlayer

    Y. Morita, K. Kuramochi, T. Onoue, T. Asahi, T. Osaka

    Journal of the Magnetics Society of Japan   24   271 - 274  2000

  • Analysis of the Remanent Magnetization State at Track Edges for a Ring-Type Head and Single-Layered Perpendicular Magnetic Recording Medium

    T. Hirayama, T. Onoue, T. Asahi, T. Honma, J. Hokkyo, T. Osaka

    Journal of the Magnetics Society of Japan   24   223 - 226  2000

  • Development of HAUP and Its Applications to Various Kinds of Solids

    J. Kobayashi, T. Asahi

    Proceedings of SPIE   4097   25 - 39  2000  [Refereed]

  • Application of Si Amorphous Underlayers to CoCrPtTa Perpendicular Magnetic Recording Media

    T. Asahi, T. Onoue, M. Ikeda, Y. Morita, T. Osaka

    Ferrites: Proceedings of the 8th International Conference on Ferrite     1055 - 1057  2000

  • Study on Medium Noise and Remanent Magnetization State for Single-Layer Perpendicular Magnetic Recording Media

    T. Onoue, T. Asahi, T. Hirayama, J. Hokkyo, T. Osaka

    Journal of the Magnetics Society of Japan   23   45 - 48  1999

  • Fabrication of a Perpendicular/Longitudinal Composite Medium by Sputtering

    A. Takizawa, T. Onoue, M. Ikeda, T. Hirayama, T. Asahi, T. Osaka, H. Sakai

    Journal of the Magnetics Society of Japan   23   973 - 976  1999

  • Effect of a Paramagnetic CoCr40 Intermediate Layer on Magnetic Properties and Crystalline Structure of the CoCr18Pt6Ta3 Perpendicular Magnetic Recording Medium with an Amorphous C Underlayer

    T. Asahi, T. Onoue, A. Takizawa, T. Osaka

    Electrochemical Society Proceedings   99-34   304 - 314  1999  [Refereed]

  • The optical activity of lysozyme crystals

    J Kobayashi, T Asahi, M Sakurai, Kagomiya, I, H Asai, H Asami

    ACTA CRYSTALLOGRAPHICA SECTION A   54   581 - 590  1998.09  [Refereed]

     View Summary

    The components of the gyration tensor of the enzyme lysozyme were measured by using the HAUP method: g(11) = - 0.90 x 10(-5) and g(33) = 1.05 x 10(-5) at 303.4 K and a wavelength of 4880 Angstrom. The optical rotatory powers along the a and c axes in the same conditions were calculated: rho(a) = -21.3 and rho(c) = -24.8 degrees cm(-1). The optically active property of lysozyme is strange in that, although it contains a considerable quantity of alpha-helices (about 30%), the rotatory powers are unexpectedly small in magnitude, one order of magnitude less than those of quartz and with very large anisotropy. A conceptual consideration of this phenomenon is given. In order to assess the difference between the structures in both crystalline and solution states, the chirality index r was calculated to be 0.16. This value indicates that the structural change of lysozyme from the solution into the crystalline state is expressed by an increase of 19% in optical activity. From the NMR results [Smith et al. (1993), J. Mol. Biol. 229, 930-944], it is anticipated that the r value reflects the increased constraint in atomic motion in the side chains of exposed amino acid residues in the crystalline state.

  • Optical study on the phase transition of Pb0.92La0.08(Zr0.65Ti0.35)(0.98)O-3

    T Asahi, Y Itagaki, H Utsumi, H Yoshii, Kamiya, I, M Ichiki, M Takahashi, J Kobayashi

    FERROELECTRICS   208 ( 1-4 ) 459 - 469  1998  [Refereed]

     View Summary

    Optical gyration G, birefringence Delta n and their electric-field E dependences of transparent ceramics of Pb0.92La0.08(Zr-0.65 Ti-0.35)(0.98)O-3 were studied by using high accuracy universal polarimeter (HAUP) in a temperature range between 10 degrees C and 130 degrees C. The high-temperature phase manifested neither spontaneous nor induced G, while the low-temperature phase did characteristic hysteresis loops of G and Delta n with respect to E. Group-theoretical consideration of gyro-optical properties of both phases led us to the conclusion that the high-End low-temperature phases are cubic T-h and trigonal C-3, the same as found in Pb0.92La0.08(Zr0.70Ti0.30)(0.98)O-3 ceramics. The free energy function of both phases was determined by using these electro-optic effects. It is found that both ceramics undergo the same phase transition and manifest similar dielectric and optical properties.

  • The optical activity of crystalline L-aspartic acid

    T Asahi, M Takahashi, J Kobayashi

    ACTA CRYSTALLOGRAPHICA SECTION A   53   763 - 771  1997.11  [Refereed]

     View Summary

    In a project of revealing gyro-optical properties of amino acids that build up proteins, all the components of the gyration tensor and the birefringence of L-aspartic acid have been successfully measured as a function of temperature although the crystal belongs to the mono-clinic system. The temperature dependence of the rotation of the gyration surface around the crystal lographic b axis was also clarified. It is of interest that the chirality index of this crystal was found to be almost the same as that of glutamic acid, another amino acid.

  • Thermal expansion of superconducting Bi2Sr2CaCu2O8

    T Asahi, H Suzuki, M Nakamura, H Takano, J Kobayashi

    PHYSICAL REVIEW B   55 ( 14 ) 9125 - 9129  1997.04  [Refereed]

     View Summary

    Temperature dependences of thermal strains of superconducting Bi2Sr2CaCu2O8 were measured by using the two-dimensional reciprocal-lattice method of x-ray diffraction in the temperature range between 15 and 300 K. Accuracies of measuring the lattice strains attained 1.6 x 10(-6). Very small anomalies of the lattice constants and lattice volume took place at T-c of the transition point. They were caused by definite discontinuities of the thermal-expansion coefficients. Using previously reported values of specific heat and isotropic compressibility a nearly temperature-independent equivalent Gruneisen parameter gamma(T) was derived as 0.89 +/- 0.11. From the extrapolation of the lattice volume of the high-temperature phase into the superconducting temperature region, additive lattice strains were found to appear spontaneously in the superconducting phase. From this fact it was concluded that a structural phase transition of the second order took place with the onset of superconductivity.

  • Optical activity of oxo amide crystals

    T Asahi, M Nakamura, J Kobayashi, F Toda, H Miyamoto

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   119 ( 16 ) 3665 - 3669  1997.04  [Refereed]

     View Summary

    It has been known that oxo amide crystals made up of achiral molecules can be photochemically converted into optically active beta-lactams by irradiation with a high pressure mercury lamp. Although the oxo amide crystal belongs to an enantiomorphic class D-2, its optical activity could not be detected so far. We successfully measured the components of the gyration tensor of the oxo amide crystal by using the HAUP (high accuracy universal polarimeter) method: g(11) = -3.5 x 10(-4) (-79 degrees/mm), g(22) = -1.4 x 10(-4) (-32 degrees/mm), g(33) = -3.0 x 10(-4) (-68 degrees/mm) at 305 K, where the optical rotatory powers are indicated in parentheses. It has been proved by direct experiments that the optical activity of the reactant and the product in this reaction system remains unchanged over the photocyclization process.

  • Optical activity of crystalline glutamic acids

    T Asahi, H Utsumi, Y Itagaki, Kagomiya, I, J Kobayashi

    ACTA CRYSTALLOGRAPHICA SECTION A   52   766 - 769  1996.09  [Refereed]

     View Summary

    As the first study on gyro-optical properties of amino acids, temperature dependences of the gyration tensor components of L- and D-glutamic acids were measured by using the HAUP (high-accuracy universal polarimeter). It was confirmed that the corresponding tensor components of the two enantiomers are the same in magnitude but opposite in sign. It is proposed that r = (rho(C)(0) - rho(S)(0))/rho(C)(0) be defined as the 'chirality index', where rho(C)(0) and rho(S)(0) designate rotatory powers per molecule in a crystal and in a dissolved state in liquid, respectively. It represents a measure of structural contribution of optical activity (OA) in a crystal. This value is 0.992 in glutamic acids.

  • Optical properties of superconducting Bi2Sr2CaCu2O8

    J Kobayashi, T Asahi, M Sakurai, M Takahashi, K Okubo, Y Enomoto

    PHYSICAL REVIEW B   53 ( 17 ) 11784 - 11795  1996.05  [Refereed]

     View Summary

    A fundamental optical study was performed on superconducting Bi2Sr2CaCU2O8 by Using a high-accuracy universal polarimeter (HAUP). As this crystal is strongly linearly dichroic, we developed the extended HAUP theory which includes the treatments of the optical dichroisms. After having determined the optical nature of the crystal, we applied the extended HAUP method to a thin (001) plate specimen with light traveling to the front and rear directions in the specimen. These two experiments permitted us to separate the reciprocal and nonreciprocal optical effects. No sign of the nonreciprocal effects was found in the HAUP transmission experiment. A gyration tensor component g(33) takes place suddenly at T-c (90 K), increases with decreasing temperature, and reaches 1.87X10(-4) (36 degrees/mm of rotatory power) at 15 K. A steep change of birefringence hn with temperature also occurs below T-c. From the behaviors of g(33) and Delta n with temperature, it can be concluded that the crystal undergoes a second-order phase transition at T-c into an optically active class. The crystal manifests large linear dichroism, i.e., Delta m=-2.2X10(-2).

  • Optical and x-ray studies on phase transition of (NH4)(2)SO4

    T Asahi, R Ikeda, M Nakamura, T Morikawa, M Higano, H Suzuki, J Kobayashi

    FERROELECTRICS LETTERS SECTION   21 ( 1-2 ) 47 - 53  1996  [Refereed]

     View Summary

    Temperature and biasing electric field dependences of a gyration tensor component g(12) of ammoniumu sulfate were measured by using the high accuracy universal polarimeter, HAUP, together with birefringences. g(12) was found to appear abruptly at the Curie point and to keep the constant value irrespective of change of the temperature. The x-rays two-dimensional method was applied for measuring the lattice strains from 300K down to 6K.

  • Optical activity of poly-L-lactic acid in crystalline and dissolved states

    M Ichiki, T Asahi, J Kobayashi

    PHASE TRANSITIONS   56 ( 2 ) 67 - 78  1996  [Refereed]

     View Summary

    The symmetry changes of the gyration tensor components of the solid polymers with a spiral orientation am clarified with respect to the changes of the density distribution function of the constituent crystallites. Any constituent crystals of optically active polymers should be regarded as uniaxial and enantiomorphic as far as the gyration is concerned. When the density distribution becomes perfectly homogeneous in the three-dimensional space, the gyration tensor components are reduced to a single component, (8)over bar&gt;. Two rotatory powers of poly-L-lactic acid are compared; one is calculated from measured values in the solid state, the other is a measured value in chloroform solution by Goodman and D'Alagni. It is striking that the former is 10(3) times larger than the latter. This means that the helical conformations of the residues which clearly exist in the solid state are destroyed in the liquid solution.

  • STRUCTURAL AND OPTICAL-PROPERTIES OF POLY LACTIC ACIDS

    J KOBAYASHI, T ASAHI, M ICHIKI, A OIKAWA, H SUZUKI, T WATANABE, E FUKADA, Y SHIKINAMI

    JOURNAL OF APPLIED PHYSICS   77 ( 7 ) 2957 - 2973  1995.04  [Refereed]

  • OPTICAL STUDY ON THE PHASE-TRANSITION OF LEAD LANTHANUM ZIRCONATE-TITANATE PB0.92LA0.08(ZR0.70TI0.30)(0.98)O3 CERAMICS

    J KOBAYASHI, T ASAHI, M ICHIKI, K SAITO, T SHIMASAKI, H YOSHII, Y ITAGAKI, H IKAWA

    PHYSICAL REVIEW B   51 ( 2 ) 763 - 778  1995.01  [Refereed]

  • Optical activity of solid polymers

    J. Kobayashit, T. Asahi, M. Ichiki, A. Oikawa

    Ferroelectrics   171 ( 1 ) 69 - 94  1995

     View Summary

    The methods of measuring optical activity of solid polymers are reviewed. The extreme difficulty of the methods is exhibited in serious drawbacks of the traditional statistical methods. The invention of HA UP (high accuracy universal polarimeter) method by Kobayashi et al has opened a way to perfect measurements of gyro-optical properties of any solids. As an example of application of the HAUP method to helical polymers, the process of analyzing the gyration tensor components of poly-L-lactic acid and poly-D-lactic acid is illustrated in details. © 1995, Taylor &amp
    Francis Group, LLC. All rights reserved.

    DOI

  • OPTICAL-ACTIVITY AND PHASE-TRANSITION OF PB1-XLAX(ZRYTIZ)(1-X/4)O-3

    H YOSHII, T SHIMASAKI, M ICHIKI, Y ITAGAKI, T ASAHI, K SAITO, J KOBAYASHI, H IKAWA

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS   33 ( 9B ) 5435 - 5439  1994.09  [Refereed]

     View Summary

    Electric field dependences of optical activity and birefringence of Pb0.92La0.08(Zr0.7Ti0.3)(0.98)O-3(PLZT(8/70/30)) were studied using the high-accuracy universal polarimeter (HAUP) method in a temperature region between 0 degrees C and 90 degrees C. PLZT(8/70/30) was optically active in the low-temperature and inactive in the high-temperature phases. Furthermore it was revealed that gyration and birefringence in the low-temperature phase manifested typical butterfly hysteresis loops with respect to electric fields. From analysis of Weissenberg photographs, the ceramics of both high- and low-temperature phases were found to consist of crystallites which were distributed in equal weight along the total solid angles. Using the combined evidence from HAUP and X-ray methods, it was clarified that the classes of the high- and low-temperature phases are T-h and C-3, respectively.

  • Optical Activity of (NH4) 2SO4

    M. Higano, T. Asahi, Y. Sato, K. Okubo, J. Kobayashi

    Ferroelectrics   152   285 - 287  1994

  • Optical properties of plzt

    Masaaki Ichiki, Tsuyoshi Shimasaki, Hiroshige Yoshii, Toru Asahi, Jinzo Kobayashf, Hiroyuki Ikawa

    Ferroelectrics   152 ( 1 ) 289 - 293  1994

     View Summary

    Optical properties of PLZT(8/70/30) in various phases were studied by using HAUP method. Ferroelectric phase was found to be optically, active. From this result, it was revealed that the point group of PLZT should be C3 in the rhombohedral system(ferroelectric phase). Peculiar electric field dependences of gyration and birefringence in the intermediate phase were found. © 1994, Taylor &amp
    Francis Group, LLC. All rights reserved.

    DOI

  • Optical activity of gd2(mo04)3

    Kazuya Saito, Toru Asahi, Nobuko Takahashi, Michi Higano, Itaru Kamiya, Yasuyuki Sato, Kazuya Okubo, Jinzo Kobayashi

    Ferroelectrics   152 ( 1 ) 231 - 236  1994

     View Summary

    Temperature dependences of gyration tensor component g11 and birefringence An of Gd2(MoO4)3 were measured at various wavelength by using high accuracy universal Polarimeter (HAUP). Spontaneous values of gn and An in the ferroelectric phase increased with decreasing temperature, but quadratic relations with respect to spontaneous polarization did not hold. The spontaneous Ans showed an anomalous peak at a wavelength of 334.7nm. Such a phenomenon has not been reported to date in any ferroelectrics. © 1994, Taylor &amp
    Francis Group, LLC. All rights reserved.

    DOI

  • Optical Activity of (NH4) 2SO4

    M. Higano, T. Asahi, Y. Sato, K. Okubo, J. Kobayashi

    Ferroelectrics   152   285 - 287  1994  [Refereed]

  • OPTICAL ACTIVITY IN POLY-L-LACTIC ACID

    Jinzo Kobayashi, Masaaki Ichiki, Taku Watanabe, Toru Asahi, Atsushi Oikawa, Hiro Suzuki

    FERROELECTRICS   151 ( 1 ) 75 - 84  1994  [Refereed]

     View Summary

    Optical activity of a helical polymer, poly-L-lactic acid, was studied by using x-rays and HAUP methods. Gyrations depend considerably on the drawing actions. From the relation between gyrations and drawing ratios, the gyration tensor components are determined as g(1)=(-2.7 +/- 0.5) x10(-4) and g(3)=(8.3 +/- 0.2) x 10(-2). It is striking that a helical polymer like this material produces huge gyration along the helical chain.

  • OPTICAL STUDY OF PB1-XLAX(ZRYTIZ)1-(X/4)O3

    M ICHIKI, T ASAHI, T SHIMASAKI, J KOBAYASHI, H IKAWA

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS   31 ( 9B ) 3212 - 3213  1992.09  [Refereed]

     View Summary

    Optical properties of La-modified lead zirconate titanate (9/65/35) in the intermediate phase were studied by the HAUP (high accuracy universal polarimeter) method. It was found that this material is optically inactive under electric fields. On the other hand, temperature dependence of the quadratic electrooptic coefficient was measured after careful corrections using the HAUP method.

  • OPTICAL-PROPERTIES OF BAMNF4

    T ASAHI, M TOMIZAWA, J KOBAYASHI, W KLEEMANN

    PHYSICAL REVIEW B   45 ( 5 ) 1971 - 1987  1992.02  [Refereed]

     View Summary

    Optical properties of pyroelectric and antiferromagnetic BaMnF4 were studied by using a high-accuracy universal polarimeter in the temperature range including the incommensurate phase transition point T(i). Both phases above and below T(i) were found to be optically active. The active gyration tensor components g(ij) were consistent with the reported symmetry of the crystal, i.e., C2-upsilon and C2 above and below T(i). Temperature dependences of all the gyration components were measured. It is striking that g23, which exists commonly in both phases, manifested itself a sharp peak at T(i). This divergence of g23 makes the transition perfectly second order. g11 along the incommensurate a axis develops conspicuously. The present results of the birefringences did not perfectly agree with previous reports: Although the temperature dependence of DELTA-n(c) coincided with the result of Schafer et al., those of DELTA-n(a) and DELTA-n(b) were quite different in their report. Rotation of the indicatrix takes place only around the a axis of the low-temperature phase. This fact confirms the validity of the point group C2 of the low-temperature phase. The rotation angle of the indicatrix was found to be one order of magnitude larger than that of the crystallographic axes. The rotation angle of the gyration surface was also evaluated. It is approximately two orders of magnitude larger than the rotation angle of the indicatrix. This fact clearly indicates that gyrations are very sensitively affected by the change of the order parameter.

  • Optical and Structural Studies of Poly-Lactic Acid (II)

    M. Ichiki, T. Asahi, T. Watanabe, J. Kobayashi, E. Fukada

    Reports on Progress in Polymer Physics in Japan   35   445 - 448  1992

  • Optical and Structural Studies of Poly-Lactic Acid (I)

    M. Ichiki, T. Asahi, T. Watanabe, J. Kobayashi, E. Fukada

    Reports on Progress in Polymer Physics in Japan   35   441 - 444  1992

  • Optical Properties of Gd2 (MoO4) 3 Studied by High Accuracy Universal

    T. Asahi, M. Higano, Cao Fu-Tian, J. Kobayashi

    Japanese Journal of Applied Physics   31   3214 - 3217  1992  [Refereed]

  • OPTICAL-PROPERTIES OF ROCHELLE SALT

    J KOBAYASHI, K UCHINO, T ASAHI

    PHYSICAL REVIEW B   43 ( 7 ) 5706 - 5712  1991.03  [Refereed]

     View Summary

    Simultaneous measurements of the gyration, birefringence, and rotation angle of the optical indicatrix of Rochelle salt were successfully performed by using high-accuracy universal polarimetry. The three phases of the crystal were found to be optically active. It was revealed that the origin of ferroelectricity of the crystal is directly responsible for the occurrence of the optical activity. Birefringence in the ferroelectric phase cannot be explained by the usual electro-optic effect. Two possibilities are considered for this discrepancy.

  • OPTICAL-ACTIVITY OF POLY-L-LACTIC ACID

    T ASAHI, H FUKASE, M ICHIKI, J KOBAYASHI, E FUKADA

    FERROELECTRICS   109   339 - 342  1990  [Refereed]

  • OPTICAL-ACTIVITY OF BAMNF4

    T ASAHI, K UCHINO, M TOMIZAWA, J KOBAYASHI, W KLEEMANN

    FERROELECTRICS   105   213 - 217  1990  [Refereed]

  • THE OPTICAL STUDY OF BAMNF4 IN INCOMMENSURATE PHASE

    T ASAHI, K UCHINO, J KOBAYASHI, W KLEEMANN

    FERROELECTRICS   94   329 - 335  1989  [Refereed]

  • EVALUATION OF THE SYSTEMATIC-ERRORS OF POLARIMETRIC MEASUREMENTS - APPLICATION TO MEASUREMENTS OF THE GYRATION TENSORS OF ALPHA-QUARTZ BY THE HAUP

    J KOBAYASHI, T ASAHI, S TAKAHASHI, AM GLAZER

    JOURNAL OF APPLIED CRYSTALLOGRAPHY   21   479 - 484  1988.10  [Refereed]

  • SIMULTANEOUS MEASUREMENTS OF ELECTROGYRATION AND ELECTROOPTIC EFFECTS OF ALPHA-QUARTZ

    J KOBAYASHI, T ASAHI, S TAKAHASHI

    FERROELECTRICS   75 ( 1-2 ) 139 - 152  1987  [Refereed]

▼display all

Books and Other Publications

  • CSJカレントレビュー13「キラル化学-その起源から最新のキラル材料研究まで」

    朝日透, 田中真人

    化学同人  2013.10

  • 「異方性媒質のキラル光学/磁気光学の精密測定&nbsp;」

    朝日透

    磁気学会  2013

  • 生命科学概論

    朝日透, 池田康夫, 石井義孝, 井上貴文, 大坂利文, 大島登志男, 岡村好子, 合田亘人, 澤村直哉, 重谷安代, 仙波憲太郎, 武岡真司, 武田直也, 竹山春子, 常田聡, 増田優, 南沢享

    朝倉出版  2012

  • Magnetic Materials, Processes, and Devices 9 : ECS Transaction Vol. 3 No.25

    J. Sayama, Y. Yamashita, T. Asahi, T. Osaka

    2007

  • SPIE Press

    T. Asahi, J. Kobayashi

    2003

  • Introduction to Complex Mediums for Optics and Electromagnetics SPIE PRESS

    T. Asahi, J. Kobayashi

    2003

  • 今日からモノ知りシリーズ トコトンやさしいナノテクノロジーの本

    大泊 巌

    2002.03

▼display all

Industrial Property Rights

  • 藻類由来の成分を含む細胞培養用組成物、及びそれを用いた細胞培養方法

    岡本 裕太, 朝日 透

    Patent

  • 磁気異方性垂直磁化膜及びその形成方法並びに磁気記録媒体及びその製造方法

    5177407

    逢坂 哲彌, 朝日 透, 杉山 敦史, 吉野 正洋, 小泉 公

    Patent

  • バイオセンシング方法及び固定化方法

    4911639

    逢坂 哲彌, 松永 是, 新垣 篤史, 朝日 透, 横島 時彦, 丹波 大介

    Patent

  • 磁気記録媒体用基板及び磁気記録媒体

    逢坂 哲彌, 朝日 透, 横島 時彦

    Patent

  • 磁気記録媒体

    逢坂 哲彌, 朝日 透, 川治 純

    Patent

  • 金属針構造体及びその製造方法

    4742187

    逢坂 哲彌, 大島 忠平, 朝日 透, 六田 英治, 郭 鴻曦, 鄭 天佐

    Patent

  • 電子光学装置用電子ビーム源及びその製造方法

    4543129

    逢坂 哲彌, 大島 忠平, 朝日 透, 六田 英治, 板垣 孝洋

    Patent

  • 量子化コンダクタンス素子、これを用いた磁場変化検出方法及び磁気検出方法、並びに量子化コンダクタンス素子の製造方法

    逢坂 哲彌, 大島 忠平, 朝日 透, 六田 英治

    Patent

  • 磁気記録媒体及び磁気記録媒体基板

    朝日 透, 横島 時彦, 逢坂 哲彌

    Patent

  • Sm-Co合金系垂直磁気異方性薄膜およびその形成方法

    4614046

    佐山 淳一, 逢坂 哲彌, 朝日 透

    Patent

  • バイオセンシング方法及び固定化方法

    4257513

    逢坂 哲彌, 横島 時彦, 朝日 透, 松永 是, 新垣 篤史, 丹羽 大輔

    Patent

  • 垂直磁気記録媒体の製造方法

    4408210

    逢坂 哲彌, 朝日 透, 横島 時彦

    Patent

  • 磁気記録媒体、その製造方法及び磁気記憶装置

    逢坂 哲彌, 朝日 透, 横島 時彦

    Patent

  • 磁気記録媒体の製造方法

    4138348

    朝日 透, 川治 純, 逢坂 哲彌

    Patent

▼display all

Research Projects

  • Toward the implementation of evidence-based health policies to the real world-a trial of using big data analyses by the integration of arts and sciences

    Project Year :

    2019.06
    -
    2023.03
     

  • New Type Catheter Using Photomechanical Crystal Actuator

    Project Year :

    2016.04
    -
    2018.03
     

     View Summary

    Endoscope and catheter are important medical equipment for inspection and treatment in modern medicine. We have recently developed various photomechanical crystals, which bend upon light irradiation. In this study, we tried to develop new light-driven catheter by using the photomechanical crystals as the actuator. As the results of measurements of Young's modulus and stress as well as the durability of repeated bending, the photomechanical crystals revealed to be available for light-driven actuator. A new photomechanical crystal was also developed which had fast bending speed of 5 Hz. Finally, a prototype light-driven actuator could be made by connecting a photomechanical crystal and an optical fiber. Further improvement is necessary to realize new light-driven catheter enduring practical use

  • Reverse reaction of thalidomide hydrolytic product to thalidomide for reconsidering metabolic pathway of thalidomide

    Project Year :

    2014.04
    -
    2016.03
     

     View Summary

    Recently, Thalidomide(TD) has attracted attention again because of rediscovery of drug efficacy against some intractable diseases. Previously, we found that α- (2-Carboxybenzamido) glutarimide (CBG), which is a primary hydrolysis product of TD in vivo, slowly changed to TD through dehydration in organic solvents such as acetonitrile. In this study, to comprehend its mechanisms, we investigated the dehydration of CBG under various conditions and examined whether the dehydration occur on phthaloylisoglutamine (PIG) and phthaloylglutamine (PG), which are other primary hydrolysis products of TD. We have concluded that the dehydration of CBG occurred in acetonitrile and ethanol within a range of 20-60 oC, whereas PIG and PG were not dehydrated in the condition described above. Moreover, the kinetics of CBG dehydration suggests that the reaction mechanism was not simple first-order reaction but catalytic reaction which involve both TD and CBG as a catalyst

  • Functional modification of live cells by focused ion beam doping

    Project Year :

    2012.04
    -
    2014.03
     

     View Summary

    A novel heavy-metal implantation method for living cells using focused ion-beam (FIB) were proposed. We performed Au and As ion doping into living cells by using the FIB implantation method; then intracellular level of adenosine triphosphate (ATP) molecule, which is the energy storing molecule for organisms, was evaluated. The ATP level of the implanted cells was found to be modified compared with that of the non-implanted control cells. Our ion implantation technique may be a more accurate tool to quantitatively elucidate the dose-dependent effects of dopants than the conventional methods

  • Constructing cDNA for hypothesis verification of crystal melting of Ca2+driven contractile protein

    Project Year :

    2011.04
    -
    2014.03
     

     View Summary

    1)In order to analyze peptide sequences of a putative protein of spaconnectin which considered to have a co-operative contractile role with the another protein (spasmin), Thus, we intended to collect the peritrich ciliate (Zoothamnium arbuscula strain Lake Biwa) at the shallow water around the Karasuma Peninsula at Lake Biwa. The physiological role of this spaconnectin is supposed to be entropic contraction of spasmoneme.2) In this year, we could get abundant amounts of the organisms. And We have also collected and incubated some amounts of green vorticella and other species for determining small subunit RNA genes in pure ethanol. 3)We intended to investigate if animal erythrocyte have properties of Ca2-stimulative contraction similarly as vorticellae stalk. Cow erythrocyte was tested. Result of research was obscure so the the Jenopus erythrocyte was investigated. The result was successful. It means that the erythrocyte contracted at about 10µ amounts of Ca2+

  • STUDY ON RECORDING CHARACTERISTICS OF MULTILAYERED THIN FILM MAGNETIC RECORDING MEDIA

    Project Year :

    2001
    -
    2003
     

     View Summary

    1. Analytical method for calculation of read-write characteristics of perpendicular magnetic recording was investigated.
    2. Theory of recording medium noise from magnetic clusters and estimation method of the noise sources were investigated.
    3. Thin Pd/Si seedlayer for Co/Pd multilayer perpendicular magnetic recording media was developed. The addition of N_2 to Ar gas during the Pd upper-seedlayer deposition and the post-annealing in preparing the Pd/Si seedlayer were effective for decreasing the magnitude of intergranular exchange coupling without serious deterioration of the perpendicular magnetic anisotropy, which resulted in both an increase in the read-write resolution and a decrease in the medium noise.

  • Study of recording and reproducing process in high density magnetic recording

    Project Year :

    1998
    -
    2000
     

     View Summary

    1. Analytical method for solving magnetic field distribution of magnetic heads : Integral Equation / Fourier Analysis Method have been constructed for solving magnetic head field distributions
    2. Analytical method for solving recording and reproducing characteristics : Recording and reproducing characteristics on single layer perpendicular recording media and double-layered perpendicular recording media have been analyzed.
    3. Theoretical analysis of noise from magnetic recording media : Power spectral density of noise caused from the magnetic clusters in the recording layer has been analyzed theoretically. The cluster size calculated based on the theory agreed well with that obtained experimentally by a magnetic force microscope.
    4. Design of magnetic materials for recording media :
    It has been found that a new composite recording medium having a Co/Pd artificial lattice magnetic layer on an amorphous carbon underlayer has extremely large magnetic anisotropy field (≒20kOe), high recording resolution and low noise properties.

  • 磁気マイクロアレイを用いた1細胞トラップ技術の開発

     View Summary

    近年、1細胞レベルで分析するための要素技術の開発が行われている。レーザーや電気化学的な力を利用した技術が報告されているが、大型の装置を必要とするため、他の手法の開発も待望されている。本研究では、磁気誘導による1細胞トラップ技術を開発することを目的としている。磁性体をアレイ化した磁気マイクロアレイを作製し、抗体をアセンブルした磁気ナノ粒子を用いることで、磁気誘導によりターゲット細胞をトラップする。本細胞トラップ技術により作製された細胞アレイは、細胞間シグナル伝達物質解析における有用なツールとなることが予測され、創薬領域に大きく貢献すると期待される。シリコン基板上のマイクロサイズのホールアレイに無電解めっき法により、CoNiFe面内軟磁性体を導入し、磁気マイクロアレイを作製した。また、細胞の磁性化として、磁性細菌により合成されたProtein A発現磁気ナノ粒子を用いた。Raji細胞(B cell line)にマウス由来抗CD19抗体を導入した後、抗マウスIgG抗体固定化磁気ナノ粒子を導入し、細胞への磁性化を行った。この磁性化細胞を3種類の磁気マイクロアレイ上に導入し、洗浄後、基板表面の顕微鏡観察を行った。その結果、磁性ドットが基板面より突き出て埋め込まれた基板Aではその突き出た磁性ドットの側面に細胞がトラップされ、また基板面と同じ高さで埋め込まれた基板Bでは磁性ドットの上に細胞が観察された。一方、埋め込まれた高さが基板面に満たない基板Cでは細胞のトラップは観察されず、チェーン状の未反応磁気ナノ粒子の凝集体(1マイクロ程度)がドット内に突き刺さっているような形で観察された。以上の結果より、基板面と同じ高さで埋め込まれたCoNiFe面内軟磁性体の磁気マイクロアレイを用いることにより、1つの細胞のトラップが可能であることが実証された

  • 磁性ドットおよび改質表面磁性膜によるターゲット細胞トラップ技術の開発

     View Summary

    1細胞のマニュピュレーション技術として、磁気マイクロドットアレイによる細胞トラップ技術を開発した。(1) 磁性材料の細胞生育への影響本研究では、アレイに用いる磁性素材として、CoMFe系磁性膜を選択した。Si基板上に成膜した磁性膜の細胞毒性を評価した結果、24時間後においても磁性膜基板を導入した細胞において生育が観察され、細胞への毒性が低いことが示唆された。(2) 細胞への磁気標識細胞への磁性化として、B細胞系のRaji細胞(CD19陽性細胞)及び磁性細菌が合成するProtein G発現磁気ナノ粒子を用いた。Raji細胞へ特異的に磁気標識が行えているかを確認するために、Cy3及び抗GD19抗体を導入した磁気ナノ粒子を細胞に標識した後、Alexa488-抗CD19抗体を導入した。洗浄後の細胞についてCy3及びAlexa488の蛍光をもとに1細胞表面の磁気ナノ粒子の分布を解析した結果、抗原部位と磁気ナノ粒子の局在部位に関して93.3%の重複が確認された。(3) 末梢血からの標的細胞の磁気分離末梢血からの直接的な磁気細胞分離を試みた。B細胞及びT細胞の表面抗原(CD19, CD20, CD3)に対する抗体をそれぞれ磁気ナノ粒子に固定化後、末梢血に希少な割合でしか含まれていない細胞を分離した。その結果、磁気ナノ粒子は他の細胞に非特異的に結合することなく、90%以上の高純度において磁気分離できることが示された。(4) 磁性ドットアレイを用いた細胞トラップSi基板上にマイクロパターン技術を用いてドット径、ドット間距離を変えたマイクロアレイを作製し、無電解めっき法により磁性ドットアレイの作製に成功した。MFeB磁石の上にアレイを設置し、磁気ビーズとしてSpherobeads、また磁気ナノ粒子で標識した細胞をマイクロアレイ上に導入することに成功した

▼display all

Presentations

  • CeF3単結晶の光軸に垂直な方向のFaraday効果の正確な測定

    中川鉄馬, 張堃, 朝日透

    日本磁気学会学術講演会 

    Presentation date: 2018.09

  • アミノ酸ドープ硫酸トリグリシン結晶の強誘電性とキラリティ

    寺沢有果菜, 石川和彦, 一木正聡, 朝日透

    日本物理学会 2018年秋季大会 

    Presentation date: 2018.09

  • 最適及びアンダードープBi2Sr2CaCu2O8+xの光学的性質と対称性の破れ

    チョウコン, 松本匡貴, 中川鉄馬, 松田梓, 朝日透, 綿打敏司

    日本物理学会 2018年秋季大会 

    Presentation date: 2018.09

  • サリチリデンナフチルアミン結晶の光トリガー相転移

    谷口卓也, 佐藤寛泰, 朝日透, 小島秀子

    2018年光化学討論会 

    Presentation date: 2018.09

  • ビスチミン誘導体の自己集体内の光化学反応と形態変化

    稲田萌花, 宇田川瑛弘, 齋藤敬, 小島秀子, 朝日透

    2018年光化学討論会 

    Presentation date: 2018.09

  • Mechanical Motions of Salicylideneaniline Crystals Induced by Light and Heat

    HAGIWARA Yuki, TANIGUCHI Takuya, KOSHIMA Hideko, ASAHI Toru

    2018年光化学討論会 

    Presentation date: 2018.09

  • Application of HAUPs to Amino Acid Crystals: Dedicated to Professor Jinzo Kobayashi

    T.Asahi, K.Ishikawa, Y.Terasawa

    4th Molecular Chirality Asia 

    Presentation date: 2018.07

  • Thermal Locomotion of Chiral Crystal by Phase Transition

    Takuya Taniguchi, Haruki Sugiyama, Hidehiro Uekusa, Motoo Shiro, Hideko Koshima, Toru Asahi

    4th Molecular Chirality Asia 

    Presentation date: 2018.07

  • Chirality Control of Tryglycine Sulfate Crystals by Chiral Molecules

    Yukana Terasawa, Kazuhiko Ishikawa, Masaaki Ichiki, Toru Asahi

    4th Molecular Chirality Asia 

    Presentation date: 2018.07

  • Chiral Inversion of Thalidomide Enantiomers in their Powder State

    Kanako Shinohara, Yuka Niizuma, Kohei Tanaka, Kohei Otogawa, Yoshiyuki Ogino, Fumiya Adachi, Toru Asahi

    4th Molecular Chirality Asia 

    Presentation date: 2018.07

  • Enhancement of Racemization in Powdered Thalidomide by Heating

    Kanako Shinohara, Yuka Niizuma, Kohei Tanaka, Kohei Otogawa, Yoshiyuki Ogino, Fumiya Adachi, Toru Asahi

    Chirality 2018 

    Presentation date: 2018.06

  • Relationship between Chirality and Ferroelectricity of Alanine doped Triglycine sulfate crystals

    Yukana Terasawa, Kazuhiko Ishikawa, Masaaki Ichiki, Toru Asahi

    RCBJSF 2018 

    Presentation date: 2018.05

  • アミノ酸をドープした硫酸鳥グリシン決勝の物性測定

    楠田晃孝, 崎山菜緒, 寺沢有果菜, 朝日透

    モレキュラー・キラリティー 2018 

    Presentation date: 2018.05

  • アラニンによる硫酸トリグリシン結晶のキラリティ制御機構

    寺沢有果菜, 石川和彦, 一木正聡, 朝日透

    モレキュラー・キラリティー 2018 

    Presentation date: 2018.05

  • 粉末状態サリドマイドエナンチオマーのキラル反転の解析

    篠原加奈子, 新妻優花, 田中康平, 乙川光平, 荻野禎之, 足立風水也, 朝日透

    モレキュラー・キラリティー 2018 

    Presentation date: 2018.05

  • アラニンによる強誘電性硫酸トリグリシン結晶のキラリティ制御

    寺澤有果菜, 石川和彦, 一木正聡, 朝日透

    2018年日本物理学会 

    Presentation date: 2018.03

  • サリチリデンアニリン結晶における光屈曲の高速化

    小島秀子, 小宮潤, 谷口卓也, 山中大樹, 古部昭広, 杉山晴紀, 植草秀裕, 佐藤寛泰, 朝日 透

    日本化学会第98春季年会 

    Presentation date: 2018.03

  • ジベンゾバレレン結晶の光屈曲

    谷口卓也, 久保田あゆみ, 守時達也, 朝日透, 小島秀子

    日本化学会第98春季年会 

    Presentation date: 2018.03

  • Thermal and Photo-triggered Phase Transition of Chiral Photochromic Salycilidenenaphthylethylamine crystal

    TANIGUCHI, Takuya, SUGIMOTO, Ryota, KOMIYA, Jun, SATO, Hiroyasu, KOSHIMA, Hideko, ASAHI, Toru

    日本化学会第98春季年会 

    Presentation date: 2018.03

  • Nafion塗布メソポーラスPd薄膜を用いた乳酸のセンシング

    馬場大輔, 山内悠輔, 朝日透

    日本化学会第98春季年会 

    Presentation date: 2018.03

  • G-HAUP opens the door to condensed matter Chirality

    T.Asahi

    Toyota-Riken International Workshop 

    Presentation date: 2017.11

  • Photo- and Thermal-induced Mechanical Motion of Chiral Salicylideneaniline Crystals

    Taniguchi Takuya, Sugimoto Ryota, Komiya Jun, Koshima Hideko, Asahi Toru

    2017年光化学討論会 

    Presentation date: 2017.09

  • Photochemical Reaction of Bis-Thymine Derivatives in Selfassembly

    A. Udagawa, M. Inada, A. Al-Shereiqi, H. Koshima, K. Saito, T. Asahi

    2017年光化学討論会 

    Presentation date: 2017.09

  • Photo- and Thermo-induced Mechanical Motion of Aminosalicylideneaniline Crystals

    J. Komiya, T. Taniguchi, D. Yamanaka, A. Furube, H. Koshima, T. Asahi

    2017年光化学討論会 

    Presentation date: 2017.09

  • 精神遅滞原因候補遺伝子cereblonの分子進化速度解析による機能的サイトの解明

    小野寺航, 朝日透, 澤村直哉

    第19回日本進化学会 

    Presentation date: 2017.08

  • Cereblon promotes itochondrial degradation via autophagy in human neuroblastoma cells

    Kosuke Kataoka, Toru Asahi, Naoya Sawamura

    第60回日本神経化学会大会 

    Presentation date: 2017.08

  • Solution and Solid State Chiroptical Analysis for Dynamic Multimerization of Thalidomide

    Kohei Tanaka, Yoshiyuki Ogino, Hiroki Toriyama, Tomoha Tohaya, Masahito Tanaka, Togo Shimozawa, Toru Asahi

    29th International Symposium of Chiral Discrimination 

    Presentation date: 2017.07

  • Thermally-Induced Racemization of Powder Thalidomide

    Yuka Niizuma, Kohei Tanaka, Miri Nakamura, Kohei Otogawa, Toru Asahi

    29th International Symposium of Chiral Discrimination 

    Presentation date: 2017.07

  • Thermally-Induced Racemization of Powder Thalidomide

    Yuka Niizuma, Kohei Tanaka, Miri Nakamura, Kohei Otogawa, Toru Asahi

    29th International Symposium of Chiral Discrimination 

    Presentation date: 2017.07

  • Spontaneous Dehydration Mechanism of Thalidomide Hydrolysis Products in Organic Solvent

    Miri Nakamura, Yoshiyuki Ogino, Togo Shimozawa, Kohei Otogawa, Yuka Niizuma, Toru Asahi

    29th International Symposium of Chiral Discrimination 

    Presentation date: 2017.07

  • The Physical Properties of Various Amino Acids Doped Triglycine Sulfate Crystals

    Nao Sakiyama, Yukana Terasawa, Kazuhiko Ishikawa, Toru Asahi

    29th International Symposium of Chiral Discrimination 

    Presentation date: 2017.07

  • Controlling Chirality of Triglycine Sulfate Crystal by the Addition of Alanine

    Yukana Terasawa, Kazuhiko Ishikawa, Toru Asahi

    29th International Symposium of Chiral Discrimination 

    Presentation date: 2017.07

  • Optical Properties of Langasite Family Ca3TaAl3Si2O14 Single Crystals

    Kenta Nakagawa, Xiuwei Fu, Garcia Villora, Kiyoshi Shimamura, Toru Asahi

    29th International Symposium of Chiral Discrimination 

    Presentation date: 2017.07

  • Physicochemical Properties in L-lactic Acid Doped Ferroelectric Triglycine Sulfate

    Tomoro Kawatani, Kazuhiko Ishikawa, Yukana Terasawa, Masaaki Ichiki, Toru Asahi

    29th International Symposium of Chiral Discrimination 

    Presentation date: 2017.07

  • Photomechanical Motion of Chiral Crystals Formed from Achiral Aminosalicylideneaniline

    Jun Komiya, Masafumi Matsudomi, Daiki Yamanaka, Akihiro Furube, Hideko Koshima, Toru Asahi

    29th International Symposium of Chiral Discrimination 

    Presentation date: 2017.07

  • Photomechanical Motion of Chiral Crystals Formed from Achiral Aminosalicylideneaniline

    Jun Komiya, Masafumi Matsudomi, Daiki Yamanaka, Akihiro Furube, Hideko Koshima, Toru Asahi

    29th International Symposium of Chiral Discrimination 

    Presentation date: 2017.07

  • Directional Locomotion of Chiral Azobenzene Crystals

    Takuya Taniguchi, Haruki Sugiyama, Hidehiro Uekusa, Motoo Shiro, Hideko Koshima, Toru Asahi

    29th International Symposium of Chiral Discrimination 

    Presentation date: 2017.07

  • Optical Properties and Broken Symmetries in Bi2Sr2CaCu2O8+x

    Kun Zhang, Masataka Matsumoto, Kenta Nakagawa, Satoshi Watauchi, Azusa Matsuda, Toru Asahi

    29th International Symposium of Chiral Discrimination 

    Presentation date: 2017.07

  • Molecular Mechanism of the Neuroprotective Effect of Thalidomide against Ischemic Neuronal Damage

    Naoya Sawamura, Mariko Yamada, Miku Fujiwara, Haruka Yamada, Hideki Hayashi, Norio Takagi, Toru Asahi

    29th International Symposium of Chiral Discrimination 

    Presentation date: 2017.07

  • Enantioselectivity Evaluation of Mesoporous Au Synthesized by Block Copolymer Assisted Electrochemical Synthesis

    Asep Sugih Nugraha, Yusuke Yamauchi, Toru Asahi

    29th International Symposium of Chiral Discrimination 

    Presentation date: 2017.07

  • Chiral Recognition by Using Mesoporous Cu Film which Absorbs Alanine

    Daisuke Baba, Toru Asahi, Yusuke Yamauchi

    29th International Symposium of Chiral Discrimination 

    Presentation date: 2017.07

  • Enantioselective/Stereoselective Recognition at Surface of Mesoporous Pd@Pt Nanoparticles

    Yuxi Fang, Toru Asahi, Yusuke Yamauchi

    29th International Symposium of Chiral Discrimination 

    Presentation date: 2017.07

  • Fast-Type High-Accuracy Universal Polarimeter Using Charge-Coupled Device Spectrometer

    Akifumi Takanabe, Masahito Tanaka, Hideko Koshima, Toru Asahi

    29th International Symposium of Chiral Discrimination 

    Presentation date: 2017.07

  • Photomechanical Motion of Chiral Azobenzene Crystals with Twisting

    Hideko Koshima, Takuya Taniguchi, Motoo Shiro, Toru Asahi

    29th International Symposium of Chiral Discrimination 

    Presentation date: 2017.07

  • Application of HAUPs to Amino Acid Crystals: Dedicated to Professor Jinzo Kobayashi

    Toru Asahi, Kazuhiko Ishikawa, Yukana Terasawa

    4th Molecular Chirality Asia 

    Presentation date: 2017.07

  • Photochemical Reaction and Self-assembly of Chiral Bis-Thymine Derivatives

    Moeka Inada, Akihiro Udagawa, Kei Saito, Hideko Koshima, Toru Asahi

    4th Molecular Chirality Asia 

    Presentation date: 2017.07

  • Thermal Locomotion of Chiral Crystal by Phase Transition

    Takuya Taniguchi, Haruki Sugiyama, Hidehiro Uekusa, Motoo Shiro, Hideko Koshima, Toru Asahi

    4th Molecular Chirality Asia 

    Presentation date: 2017.07

  • Physicochemical analyses of thalidomide and its hydlysis compounds

    Fumiya Adachi, Miri Nakamura, Yoshiyuki Ogino, Toru Asahi

    4th Molecular Chirality Asia 

    Presentation date: 2017.07

  • Optical Properties and Symmetry Breaking of Under-Doped High Temperature Superconductor Bi2Si2CaCuO8+x

    Kun Zhang, Masataka Matsumoto, Kenta Nakagawa, Azusa Matsuda, Toru Asahi

    4th Molecular Chirality Asia 

    Presentation date: 2017.07

  • Cereblon promotes mitophagy in human neuroblastoma cells

    Kosuke Kataoka, Toru Asahi, Naoya Sawamura

    第8回オートファジーに関する国際会議(ISA) 

    Presentation date: 2017.05

  • Directional Locomotion of Chiral Azobenzene Crystals by Phase Transition

    Takuya Taniguchi, Haruki Sugiyama, Hidehiro Uekusa, Motoo Shiro, Hideko Koshima, Toru Asahi

    The 23rd International Conference on the Chemistry of the Organic Solid State(ICCOSS 2017) 

    Presentation date: 2017.04

  • 水素結合を有する両親媒性Bis-Thymine誘導体の自己集合と光化学反応

    稲田萌花, 宇田川瑛弘, 齋藤敬, 小島秀子, 朝日透

    日本化学会第98春季年会 

    Presentation date: 2017.03

  • G-HAUPによる希土類弗化物 (CeF3,PrF3) 単結晶の磁気光学的研究

    中川鉄馬, ガルシアビジョラ, 島村清史, 朝日透

    日本物理学会 第72回年次大会 

    Presentation date: 2017.03

  • ドーパミンセンサへの応用を視野に入れたメソポーラス銅薄膜 の作製

    馬場大輔, 山内悠輔, 朝日 透

    日本化学会 第97春季年会 

    Presentation date: 2017.03

  • Mesoporous Gold Film electrode for high performance non-enzymatic glucose detection

    NUGRAHA, Asep, LI, Cuiling, YAMAUCHI, Yusuke, ASAHI, Toru

    日本化学会 第97春季年会 

    Presentation date: 2017.03

  • メソポーラス Pd@Pt ナノパーティクルによるキラル識別と立 体構造識別

    方 宇熙, 山内悠輔, 朝日 透

    日本化学会 第97春季年会 

    Presentation date: 2017.03

  • アンダードープBi2Sr2CaCu2O8+xの光学的性質と対称性の破れ

    篠元輝, 松本匡貴, 中川鉄馬, 綿打敏司, 松田梓, 朝日透

    日本物理学会 第72回年次大会 

    Presentation date: 2017.03

  • Physicochemical Properties in L-lactic Acid Doped Ferroelectric Triglycine sulfate

    KAWATANI, Tomoro, ISHIKAWA, Kazuhiko, TERASAWA, Yukana, ASAHI, Toru

    日本化学会 第97春季年会 

    Presentation date: 2017.03

  • Controlling Chirality of Ferroelectric Triglycine sulfate crystals by Alanine molecules

    TERASAWA, Yukana, ISHIKAWA, Kazuhiko, ASAHI, Toru

    日本化学会 第97春季年会 

    Presentation date: 2017.03

  • 2 回らせんをもつキラル結晶であるアラニン結晶の旋光性と構造の関係

    石川和彦, 寺澤有果菜, 田中真人, 朝日 透

    日本化学会 第97春季年会 

    Presentation date: 2017.03

  • キラルサリチリデンフェニルエチルアミン結晶の可逆的単結晶 -単結晶相転移

    高鍋彰文, 植草秀 裕, 城 始勇, 小島秀子, 朝日 透

    日本化学会 第97春季年会 

    Presentation date: 2017.03

  • 2 種類の蛍光強度を示す蛍光タンパク質 UnaG の蛍光特性の 解析

    下島 洋, 下澤東吾, 朝日 透

    日本化学会 第97春季年会 

    Presentation date: 2017.03

  • チミン誘導体の自己集合体中における光化学反応

    宇田川瑛弘, 小島秀子, 齋藤 敬, 朝日 透

    日本化学会 第97春季年会 

    Presentation date: 2017.03

  • CCD分光器を用いた迅速型キラル分光装置(HAUP)

    高鍋 彰文, 小島 秀子, 朝日 透

    第64回応用物理学会春季学術講演会 

    Presentation date: 2017.03

  • アミノサリチリデンアニリン結晶のフォトメカニカル機能

    小宮 潤, 松富正文, 山中大樹, 古部昭広, 小島秀 子, 朝日 透

    日本化学会 第97春季年会 

    Presentation date: 2017.03

  • 熱によって動き回るキラルアゾベンゼン結晶

    谷口卓也, 杉山晴紀, 植草秀裕, 城 始勇, 小島秀子, 朝日 透

    日本化学会 第97春季年会 

    Presentation date: 2017.03

  • ソフトロボット材料:光と熱で動くメカニカル結晶

    小島 秀子, 高鍋 彰文, 谷口 卓也, 小宮 潤, 朝日 透

    第64回応用物理学会春季学術講演会 

    Presentation date: 2017.03

  • EQUILIBRIUM OF TWO FLUORESCENCE STATES IN THE UNAG-BILIRUBIN COMPLEX

    Yoh Shitashima, Togo Shimozawa, Toru Asahi

    60th Biophysical Society Annual Meeting 

    Presentation date: 2017.02

  • Controlling chirality of triglycine sulfate crystals by alanine or L-lactic acid molecules

    Yukana Terasawsa, Kazuhiko Ishikawa, Tomoro Kawatani, Toru Asahi

    15th Symposium on Chemical Approaches to Chirality 

    Presentation date: 2017.01

  • Relationship between crystal structure and optical activity of alanine chiral crystals

    Kazuhiko Ishikawa, Yukana Terasawa, Masahito Tanaka, Toru Asahi

    15th Symposium on Chemical Approaches to Chirality 

    Presentation date: 2017.01

  • CereblonのLonプロテアーゼとしての機能解析

    片岡 孝介, 朝日 透, 澤村 直哉

    第39回日本分子生物学会年会 

    Presentation date: 2016.12

  • Inhibition of Arctic Aβ on nicotine-induced neuroprotective function through CHRNA7

    Ye Ju, Toru Asahi, Naoya Sawamura

    第39回日本分子生物学会年会 

    Presentation date: 2016.12

  • CereblonによるMeis2の転写制御機構の解析

    定方春樹, 和田丈慶, 朝日透, 澤村直哉

    第39回日本分子生物学会年会 

    Presentation date: 2016.11

  • サリドマイドの脳虚血に対する神経保護効果の分子メカニズム

    藤原美紅, 山田まりこ, 林秀樹, 山田春佳, 高木教夫, 朝日透, 澤村直哉

    第39回日本分子生物学会年会 

    Presentation date: 2016.11

  • 小胞体ストレスに着目したセレブロンの機能解析

    川井聡子, 朝日透, 澤村直哉

    第39回日本分子生物学会年会 

    Presentation date: 2016.11

  • L-乳酸ドープ硫酸トリグリシンの結晶育成と物理化学的性質

    川谷友郎, 石川和彦, 寺澤有果菜, 朝日 透

    第6回CSJ化学フェスタ2016 

    Presentation date: 2016.11

  • アラニン添加による硫酸トリグリシン結晶のキラリティ制御

    寺澤有果菜, 石川和彦, 朝日 透

    第6回CSJ化学フェスタ2016 

    Presentation date: 2016.11

  • G-HAUP法を用いたL-アスコルビン酸結晶の旋光性と円二色性に関する研究

    竹内克, 中川鉄馬, 朝日透

    第6回CSJ化学フェスタ2016 

    Presentation date: 2016.11

  • The Role of Cereblon as a Lon-type Protease

    Kosuke Kataoka, Toru Asahi, Naoya Sawamura

    ミトコンドリア学会 

    Presentation date: 2016.10

  • Photomechanical Motion of Crystals of Anthracene Derivative

    Takuya Taniguchi, Hideko Koshima, Toru Asahi

    The 12th Japan-China Joint Symposium on Conduction and Photoconduction in Organic Solids and Related Phenomena(第12回日中有機半導体会議) 

    Presentation date: 2016.10

  • Introduction of Waseda Global Entreprenur - Intrapreneur program

    Toru Asahi

    4th Dialogue for Global Innovation on "Technology and Humanity 

    Presentation date: 2016.10

  • マイクロ波エステル化における酸の効果

    小島 秀子, 石井 沙織, 小宮 潤, 三谷 友彦, 朝日 透

    第10回日本電磁波エネルギー応用学会シンポジウム 

    Presentation date: 2016.10

  • Photomechanical motion of azobenzene crystals

    Takuya Taniguchi, Hideko Koshima, Toru Asahi

    3D Lab Exchange Symposium 

    Presentation date: 2016.09

  • キラルアゾベンゼン結晶の構造相転移による移動現象

    谷口卓也, 杉山晴紀, 植草秀裕, 城始勇, 小島秀子, 朝日透

    第25回有機結晶シンポジウム 

    Presentation date: 2016.09

  • キラル分光装置(HAUP)の迅速化

    高鍋彰文, 小島秀子, 朝日透

    第25回有機結晶シンポジウム 

    Presentation date: 2016.09

  • 銅酸化物高温超伝導体Bi2Sr2CaCu2O8+xの光学的性質と対称性の破れ

    篠元輝, 松本匡貴, 中川鉄馬, 綿打敏司A, 松田梓, 朝日透

    日本物理学会[物性]2016年秋季大会 

    Presentation date: 2016.09

  • HABI結晶のフォトクロミック特性

    小宮潤, GAMBRILL裕美, 小島秀子, 朝日透

    2016年光化学討論会 

    Presentation date: 2016.09

  • アントリルメチレンインダノン結晶のE-Z光異性化による光屈曲

    谷口卓也, 内本英孝, 石橋禎大, 久保田あゆみ, 高橋浩三, 小島秀子, 朝日透

    2016年光化学討論会 

    Presentation date: 2016.09

  • Photo-reversible polymerization of thymine derivatives

    A.Udagawa, K.Saito, H.Uekusa, H.Koshima, T.Asahi

    2016年光化学討論会 

    Presentation date: 2016.09

  • Crystal Growth and Physicochemical Properties in L-lactic Acid Doped Triglycine sulfate

    Tomoro Kawatani, Yukana Terasawa, Kazuhiko Ishikawa, Toru Asahi

    The Internetional Chirality Symposium 2016 

    Presentation date: 2016.07

  • Controlling of Chirality of Alanine-doped Triglycine sulfate by Alanine Molecules

    Yukana Terasawa, Kazuhiko Ishikawa, Toru Asahi

    The Internetional Chirality Symposium 2016 

    Presentation date: 2016.07

  • Comprehensive definition of optical physical quantities in an anisotropic medium and its application to the field of magneto-optics

    Kenta Nakagawa, Garcia Villora, Kiyoshi Shimamura, Toru Asahi

    The Internetional Chirality Symposium 2016 

    Presentation date: 2016.07

  • Relationship between Crystal Structure and Optical Activity of Chiral Crystals with Two-fold Screw Axis

    Kazuhiko Ishikawa, Yukana Terasawa, Toru Asahi

    The Internetional Chirality Symposium 2016 

    Presentation date: 2016.07

  • Spontaneous Dehydration Mechanism of Thalidomide Hydrolysis Products in Organic Solvent

    Miri Nakamura, Kohei Otogawa, Yoshiyuki Ogino, Togo Shimozawa, Toru Asahi

    Molecular Chirality Asia 2016 

    Presentation date: 2016.04

  • Controlling Chirality of Triglycine Sulfate Chiral Crystals by Alanine Additives

    Yukana Terasawa, Kazuhiko Ishikawa, Toru Asahi

    Molecular Chirality Asia 2016 

    Presentation date: 2016.04

  • FAST PHOTOCHROMIC PROPERTIES OF PABI CRYSTALS

    Jun Komiya, Seiichi Tanaka, Ken Onda, Aya Sakon, Hidehiro Uekusa, Hideko Koshima, Toru Asahi

    26th IUPAC International Symposium on Photochemistry 

    Presentation date: 2016.04

  • PHOTOMECHANICAL BENDING WITH TWISTING OF CHIRAL AZOBENZENE CRYSTALS

    Takuya Taniguchi, Motoo Shiro, Hideko Koshima, Toru Asahi

    26th IUPAC International Symposium on Photochemistry 

    Presentation date: 2016.04

  • LIGHT-DRIVEN TWISTING MOTION OF SALICYLIDENEPHENYLETHYLAMINE SINGLE CRYSTALS

    Akifumi Takanabe, Masahito Tanaka, Kohei Johmoto, Hidehiro Uekusa, Hideko Koshima, Toru Asahi

    26th IUPAC International Symposium on Photochemistry 

    Presentation date: 2016.04

  • PHOTOMECHANICAL FUNCTION OF MOLECULAR CRYSTALS

    Hideko Koshima, Akifumi Takanabe, Takuya Taniguchi, Toru Asahi

    26th IUPAC International Symposium on Photochemistry 

    Presentation date: 2016.04

  • PABI 結晶の高速フォトクロミズム

    小宮 潤, 田中誠一, 恩田 健, 佐近 彩, 植草秀裕, 小島秀子, 朝日 透

    日本化学会第96春季年会 

    Presentation date: 2016.03

  • Enantiomeric Motion of Photomechanical Chiral Azobenzene Crys- tals

    TANIGUCHI, Takuya, SHIRO, Motoo, KOSHIMA, Hideko, ASAHI, Toru

    日本化学会第96春季年会 

    Presentation date: 2016.03

  • 蛍光特性を用いたビリルビン依存型蛍光タンパク質 UnaG の自 己二量化の解析

    下島 洋, 下澤東吾, 石田みやび, 朝日 透

    日本化学会第96春季年会 

    Presentation date: 2016.03

  • マイクロ波加熱によるエステル化反応促進における酸触媒の影響

    小島秀子, 石井沙織, 朝日 透

    日本化学会第96春季年会 

    Presentation date: 2016.03

  • フォトメカニカル機能をもつキラルなサリチリデンフェ ニルエチルアミン結晶の光学的性質

    Akifumi Takanabe, Masahito Tanaka, Kohei Johmoto, Hidehiro Uekusa, Tadashi Mori, Toru Asahi, Hideko Koshima

    第63回応用物理学会春季学術講演会 

    Presentation date: 2016.03

  • Generalized high-accuracy universal polarimeter study on chiral salicylidenephenylethylamine crystals showing photomechanical effect

    T.Asahi

    Pacifichem 2015 

    Presentation date: 2015.12

  • Chiroptical study on thalidomide in solid and solution state

    T.Asahi, H.Toriyama, Y.Ogino, M.Tanaka, T.Shimozawa, N.Shibata

    15th International Conference on Chiroptical Spectroscopy 

    Presentation date: 2015.09

  • Photo-reversible Topochemical Polymerization via [2+2]-Cycloaddition of Thymine Derivative in the Crystal

    Akihito Udagawa, Priscilla Johnston, Kei Saito, Aya Sakon, Ryosuke Toyoshima, Hidehiro Uekusa, Hideko Koshima, Toru Asahi

    ICCOSS 2015(the 22nd International Conference on the Chemistry of the Organic Solid State) 

    Presentation date: 2015.07

  • Photomechanical Bending of Chiral and Racemic Azobenzene Crystals

    Takuya Taniguchi, Juri Fujisawa, Hideko Koshima, Toru Asahi

    ICCOSS 2015(the 22nd International Conference on the Chemistry of the Organic Solid State) 

    Presentation date: 2015.07

  • High-accuracy Universal Polarimeter Study of Salicylidene-phenylethylamine Crystals with Photomechanical Function

    Akifumi Takanabe, Masahito Tanaka, Kohei Johmoto, Hidehiro Uekusa, Tadashi Mori, Toru Asahi, Hideko Koshima

    ICCOSS 2015(the 22nd International Conference on the Chemistry of the Organic Solid State) 

    Presentation date: 2015.07

  • Photomechanical Motion of Benzophenone Crystals

    Hideko Koshima, Mai Kitajima, Yuki Hagiwara, Toru Asahi

    ICCOSS 2015(the 22nd International Conference on the Chemistry of the Organic Solid State) 

    Presentation date: 2015.07

  • 精神遅滞候補遺伝子産物セレブロンのアグリソームへの集積と細胞死保護効果

    松本 広大, 若林 慧, 山田 春佳, 朝日 透, 澤村 直哉

    第67回 日本細胞生物学会大会 

    Presentation date: 2015.07

  • 精神遅滞候補遺伝子産物セレブロンのミトコンドリアにおける機能解析

    片岡孝介, 朝日透, 澤村直哉

    第67回 日本細胞生物学会大会 

    Presentation date: 2015.07

  • Optical property and symmetry breaking of copper based high-temperature superconducting material Bi2Sr2CaCu2O8+x

    Masataka Matsumoto, Kenta Nakagawa, Azusa Matsuda, Satoshi Watauchi, Toru Asahi

    Chirality 2015 

    Presentation date: 2015.06

  • Magneto-optical spectroscopic study on CeF3 single-crystal with the Generalized-High Accuracy Universal Polarimeter

    Kenta Nakagawa, G. Villora, Kiyoshi Shimamura, Toru Asahi

    11th International Conference on Ceramic Materials and Components for Energy and Environmental Applications 

    Presentation date: 2015.06

  • Chiropics of condensed matters

    Toru Asahi, Kazuhiko Ishikawa, Akifumi Takanabe, Takuya Taniguchi  [Invited]

    11th International Conference on Ceramic Materials and Components for Energy and Environmental Applications 

    Presentation date: 2015.06

  • 異方性媒質における旋光性と円二色性の新たな測定原理式の導出と光学的異方性測定

    中川鉄馬, 中村洸太, 田中真人, 朝日透

    Symposium on Molecualr Chirality 2015 

    Presentation date: 2015.06

  • Billirubin依存型蛍光タンパク質UnaGのキラル特性解析

    下島 洋, 下澤 東吾, 石田 みやび, 朝日 透

    Symposium on Molecualr Chirality 2015 

    Presentation date: 2015.06

  • サリドマイド骨格分子が示す複雑代謝挙動の実験・理論的解析

    荻野禎之, 田中真人, 柴田哲男, 朝日透

    Symposium on Molecualr Chirality 2015 

    Presentation date: 2015.06

  • 固体・溶液円二色性分光法と理論計算を用いたサリドマイドの二量体構造形成の解析

    鳥山廣樹, 荻野禎之, 下澤東吾, 柴田哲男, 田中真人, 朝日透

    Symposium on Molecualr Chirality 2015 

    Presentation date: 2015.06

  • 銅酸化物高温超伝導体Bi2Sr2CaCu2O8+dの光学的性質と対称性の研究

    松本匡貴, 松田梓, 中川鉄馬, 高鍋彰文, 朝日透

    Symposium on Molecualr Chirality 2015 

    Presentation date: 2015.06

  • サリドマイドによるエナンチオ特異的なAMPK活性調節メカニズムの解明

    藤原美紅, 山田春佳, 朝日透, 澤村直哉

    Symposium on Molecualr Chirality 2015 

    Presentation date: 2015.06

  • キラル結晶のフォトメカニカル機能

    小島秀子, 高鍋彰文, 谷口卓也, 朝日透

    Symposium on Molecualr Chirality 2015 

    Presentation date: 2015.06

  • ポリL-乳酸ナノシートの結晶化および表面物性における界面の効果

    宇田川 瑛弘, 藤枝 俊宣, 川本 裕子, 齋藤 晃広, 武岡 真司, 朝日 透

    Symposium on Molecualr Chirality 2015 

    Presentation date: 2015.06

  • アラニンのキラル結晶の光学活性と結晶構造の関係

    石川和彦, 田中真人, 城始勇, 小島秀子, 朝日透

    Symposium on Molecualr Chirality 2015 

    Presentation date: 2015.06

  • キラルなアゾベンゼン誘導体結晶の光屈曲

    谷口卓也, 城始勇, 小島秀子, 朝日透

    Symposium on Molecualr Chirality 2015 

    Presentation date: 2015.06

  • アキラルなベンゾフェノンから生成するキラル結晶の絶対構造と光学活性

    萩原裕樹, 石川和彦, 小島秀子, 朝日透

    Symposium on Molecualr Chirality 2015 

    Presentation date: 2015.06

  • サリドマイド加水分解産物の有機溶媒中における脱水反応の検証

    乙川光平, 荻野禎之, 石川和彦, 下澤東吾, 田中真人, 小島秀子, 城始勇, 朝日透

    Symposium on Molecualr Chirality 2015 

    Presentation date: 2015.06

  • ジイソプロピルベンゾフェノン系結晶のフォトクロミズムと光屈曲

    小島秀子, 高鍋彰文, 谷口卓也, 朝日透

    日本化学会第95春期年会 

    Presentation date: 2015.03

  • キラルなアゾベンゼン誘導体結晶のフォトメカニカル屈曲

    萩原裕樹, 北島麻衣, 小島秀子, 朝日透

    日本化学会第95春期年会 

    Presentation date: 2015.03

  • 2回らせんをもつアラニン結晶の旋光性と構造の関係

    石川和彦, 田中真人, 城始勇, 小島秀子, 朝日透

    日本化学会第95春期年会 

    Presentation date: 2015.03

  • 光屈曲性サリチリデンフェニルエチルアミン結晶のキラル光学特性

    高鍋彰文, 田中真人, 上本紘平, 植草秀裕, 森直, 城始勇, 小島秀子, 朝日透

    日本化学会第95春期年会 

    Presentation date: 2015.03

  • チミン誘導体結晶の[2+2]光環化付加による可逆的トポケミカル重合

    宇田川瑛弘, Priscilla Johnston, 齋藤敬, 佐近彩, 豊島良祐, 植草秀裕, 小島秀子, 朝日透

    日本化学会第95春期年会 

    Presentation date: 2015.03

  • 銅酸化物高温超伝導体の擬ギャップ相における光学的性質と対称性の研究

    松本匡貴, 松田梓, 高鍋彰文, 中川鉄馬, 朝日透

    第70回年次大会 日本物理学会 

    Presentation date: 2015.03

  • 異方性媒質における旋光性と円二色性の同時測定法

    中川鉄馬, 中村洸太, 朝日透

    第62回応用物理学会春季学術講演会 

    Presentation date: 2015.03

  • Chiroptical properties of photomechanical and anisotropic crystals of salicylidenephenylethylamine

    Akifumi Takanabe, Masahito Tanaka, Shiro Motoo, Hideko Koshima, Toru Asahi

    13th Symposium on Chemical Approaches to Chirality 

    Presentation date: 2014.11

  • Chiral spectroscopic study on thalidomide

    Toru Asahi, Hiroki Toriyama, Yoshiyuki Ogino, Masahito Tanaka, Norio Shibata

    10th International Symposium on Electrochemical Micro & Nanosystem Technologies 

    Presentation date: 2014.11

  • Construction of photoenergetic mitochondria in cultured mammalian cells: mitochondria-specific expression of a light driven proton pump

    Takeyoshi Wada, Kiyotaka Y. Hara, Kuniki Kino, Toru Asahi, Naoya Sawamura

    10th International Symposium on Electrochemical Micro & Nanosystem Technologies 

    Presentation date: 2014.11

  • Functional analysis of cereblon protein in mitochondria

    Kosuke Kataoka, Toru Asahi, Naoya Sawamura

    10th International Symposium on Electrochemical Micro & Nanosystem Technologies 

    Presentation date: 2014.11

  • Arctic Amyloid beta inhibits CHRNA7's function by specifically binding to and aggregating on this membrane receptor

    Ye Ju, Toru Asahi, Naoya Sawamura

    10th International Symposium on Electrochemical Micro & Nanosystem Technologies 

    Presentation date: 2014.11

  • Solid State Chiroptics

    Toru Asahi, Kenta Nakagawa, Takuya Taniguchi

    Molecular Chirality Asia 2014 (MC Asia 2014) 

    Presentation date: 2014.10

  • Solid State Chiroptics

    Toru Asahi, Kenta Nakagawa, Takuya Taniguchi

    Molecular Chirality Asia 2014 (MC Asia 2014) 

    Presentation date: 2014.10

  • ベンゾフェノン結晶の絶対構造と光学活性

    萩原裕樹, 石川和彦, 小島秀子, 朝日透

    第4回 CSJ化学フェスタ2014 

    Presentation date: 2014.10

  • 固体・溶液円二色性分光法と理論計算を用いたサリドマイドの二量体構造形成の解析

    鳥山廣樹, 荻野禎之, 高田成海, 田中真人, 柴田哲男, 朝日透

    第4回 CSJ化学フェスタ2014 

    Presentation date: 2014.10

  • 分光学的手法によるヒト血清アルブミンとの相互作用におけるサリドマイド関連分子の比較

    田中康平, 高田成海, 荻野禎之, 田中真人, 柴田哲男, 朝日透

    第4回 CSJ化学フェスタ2014 

    Presentation date: 2014.10

  • [2+2]光環化付加・開裂反応を利用したチミン誘導体の可逆的光トポケミカル重合

    宇田川瑛弘, JOHNSTON, 齋藤敬, 左近彩, 豊島良祐, 植草秀裕, 小島秀子, 朝日透

    2014年光化学討論会 

    Presentation date: 2014.10

  • キラルなサリチリデンフェニルエチルアミン結晶の光屈曲とキラル光学的性質

    萩原裕樹, 石川和彦, 小島秀子, 朝日透

    2014年光化学討論会 

    Presentation date: 2014.10

  • キラルなアゾベンゼン結晶のフォトメカニカル機能

    谷口卓也, 藤澤珠里, 小島秀子, 朝日透

    2014年光化学討論会 

    Presentation date: 2014.10

  • 固体・液体円二色性分光と理論計算によるサリドマイド二量体構造形成の解析

    第8回分子科学討論会2014 

    Presentation date: 2014.09

  • Doping gold ion into living cells with a low energy focused ion-beam increases proliferation activity

    Tatsuhiro Nomaguchi, Naoya Sawamura, Takahiro Shinada, Toru Asahi

    19th International Conference on Ion Beam Modification of Materials 

    Presentation date: 2014.09

  • キラルなアゾベンゼン結晶のフォトメカニカル機能の探索

    有機結晶シンポジウム 

    Presentation date: 2014.09

  • Measurement of chiroptical properties of nickel sulfate hexahydrate with G-HAUP

    Kazuhiko Ishikawa, Kenta Nakagawa, Masahito Tanaka, Toru Asahi

    IUCr 2014 (23rd IUCr Congress) 

    Presentation date: 2014.08

  • Determination of chirality of the chiral space groups with two-fold screw axis

    Masahito Tanaka, Motoo Shiro, Toru Asahi

    IUCr 2014 (23rd IUCr Congress) 

    Presentation date: 2014.08

  • Optical properties of chiral photomechanical salicylideneaniline crystal

    Akifumi Takanabe, Masahito Tanaka, Shiro Motoo, Hideko Koshima, Toru Asahi

    IUCr 2014 (23rd IUCr Congress) 

    Presentation date: 2014.08

  • Chiroptical study on benzil crystal using G-HAUP

    Kazuhiko Ishikawa, Toru Asahi

    IUCr 2014 (23rd IUCr Congress) 

    Presentation date: 2014.08

  • Structural and thermal analyses of a hydrolysis compound of thalidomide

    Kohei Otogawa, Yoshiyuki Ogino, Kazuhiko Ishikawa, Masahito Tanaka, Motoo Shiro, Tetsuya Osaka

    IUCr 2014 (23rd IUCr Congress) 

    Presentation date: 2014.08

  • The absolute structure and optical activity of alanine crystals

    Masahito Tanaka, Motoo Shiro, Toru Asahi

    Chirality 2014 (ISCD-27) 

    Presentation date: 2014.07

  • Absolute structure and chiroptical properties of benzil crystals

    Kazuhiko Ishikawa, Toru Asahi

    Chirality 2014 (ISCD-27) 

    Presentation date: 2014.07

  • Chiroptical and theoretical study on the complex systems in thalidomide metabolism and chiral inversion

    Masahito Tanaka, Norio Shibata, Toru Asahi

    Chirality 2014 (ISCD-27) 

    Presentation date: 2014.07

  • Solvent free thermally-induced recemization of thelidmide and dehydration of hydrolysis compound of thalidmide

    Norio Shibata, Toru Asahi

    Chirality 2014 (ISCD-27) 

    Presentation date: 2014.07

  • OPTICAL PROPERTIES OF CHIRAL SALYCILIDENEPHENILETHYLAMINE CRYSTALS WITH PHOTOMECHANICAL FUNCTION

    Masahito Tanaka, Motoo Shiro, Hideko Koshima, Toru Asahi

    XXVth IUPAC Symposium on Photochemistry 

    Presentation date: 2014.07

  • サリドマイド関連分子が示すヒト血清アルブミンとの相互作用の分光学的解析

    Symposium on Molecualr Chirality 2014 

    Presentation date: 2014.06

  • 固体・溶液円二色性分光を用いたサリドマイド二量体構造形成の解析

    Symposium on Molecualr Chirality 2014 

    Presentation date: 2014.06

  • Experimental and theoretical analyses for molecular behavior of thalidomide-related chiral drugs: toward a comprehensive understanding of complex metabolic systems

    鳥山廣樹, 荻野禎之, 高田成海, 田中真人, 柴田哲男, 朝日透

    OpenEye JCUP V 

    Presentation date: 2014.06

  • G-HAUP法による硫酸ニッケル6水和物結晶のキラル光学的性質の測定

    日本化学会 第94春季年会 

    Presentation date: 2014.03

  • 高密度分子状態におけるサリドマイドの分子相互作用の解明

    日本化学会 第94春季年会 

    Presentation date: 2014.03

  • ポリL-乳酸ナノシートの結晶化および表面物性における界面の効果

    日本化学会 第94春季年会 

    Presentation date: 2014.03

  • 21らせんを持つキラルなアミノ酸結晶の絶対構造と光学活性

    日本化学会 第94春季年会 

    Presentation date: 2014.03

  • キラル反転を伴う複合的代謝におけるキラルなサリドマイド分子挙動の実験・理論的解析

    日本化学会 第94春季年会 

    Presentation date: 2014.03

  • ベンゾフェノン結晶の絶対構造と光学活性

    日本化学会 第94春季年会 

    Presentation date: 2014.03

  • サリドマイド加水分解産物の単結晶X線構造解析

    第61回応用物理学会春季学術講演会 

    Presentation date: 2014.03

  • イオンビームを用いたAu2+導入による精細胞への影響検証

    第61回応用物理学会春季学術講演会 

    Presentation date: 2014.03

  • フォトメカニカル機能をもつキラルなサリチリデンアニリン結晶の光学的性質

    第61回応用物理学会春季学術講演会 

    Presentation date: 2014.03

  • 酸化ガリウム結晶の光学的異方性の測定

    第61回応用物理学会春季学術講演会 

    Presentation date: 2014.03

  • ベンジル結晶のキラル光学的性質

    第61回応用物理学会春季学術講演会 

    Presentation date: 2014.03

  • サリドマイド加水分解産物の単結晶 X 線構造解析

    第22回有機結晶シンポジウム 

    Presentation date: 2013.10

  • G-HAUP法による硫酸ニッケル6水和物のキラル光学的性質の測定

    第3回CSJ化学フェスタ2013 

    Presentation date: 2013.10

  • サリドマイドのキラル光学的研究

    第3回CSJ化学フェスタ2013 

    Presentation date: 2013.10

  • Thalidomide加水分解産物の単結晶X線構造解析

    第3回CSJ化学フェスタ2013 

    Presentation date: 2013.10

  • 連続的な加水分解とキラル反転からなるサリドマイド複雑代謝の数理モデル

    第23回日本数理生物学会大会 

    Presentation date: 2013.09

  • サリチリデンアニリン微結晶の光学的性質とメカニカル機能の関係

    2013年光化学討論会 

    Presentation date: 2013.09

  • サリドマイドのもう一つの不思議

    第12回 Conference for BioSignal and Mediceine (CBSM2013) 

    Presentation date: 2013.07

  • Arctic Amyloid βのCHRNA7受容体に対する作用

    第12回 Conference for BioSignal and Mediceine (CBSM2013) 

    Presentation date: 2013.07

  • ヒト神経芽細胞腫におけるデルタロドプシンのミトコンドリア特異的発現

    第12回 Conference for BioSignal and Mediceine (CBSM2013) 

    Presentation date: 2013.07

  • 変異型セレブロン導入によるミトコンドリア動態の解析

    第56回日本神経化学大会 

    Presentation date: 2013.06

  • Arctic Amyloid βのCHRNA7受容体に対する作用検証

    第56回日本神経化学大会 

    Presentation date: 2013.06

  • ポリL乳酸ナノシートの微細構造解析

    第62回高分子学会年次大会 

    Presentation date: 2013.05

  • キラル反転を伴うサリドマイド代謝経路の微視的解析と数理モデリング

    第20回記念シンポジウム モレキュラー・キラリティー2013 

    Presentation date: 2013.05

  • γ-Glycine結晶の絶対構造と光学活性

    日本化学会第93回春季年会 

    Presentation date: 2013.03

  • 分光学的手法によるサリドマイドとヒト血清アルブミンの相互作用解析

    日本化学会第93回春季年会 

    Presentation date: 2013.03

  • G-HAUP法による硫酸ニッケル6水和物の光学的性質の測定

    日本化学会第93回春季年会 

    Presentation date: 2013.03

  • 分光学実験と理論計算を用いたサリドマイドの複合的な代謝における分子挙動の解析

    日本薬学会第133年会 

    Presentation date: 2013.03

  • 有機ゲルマニウムGe-132の投与による酸化ストレス抑制作用

    日本薬学会第133年会 

    Presentation date: 2013.03

  • Thalidomide加水分解産物α-2-(Carboxybenzamido)-glutamineの結晶構造解析

    日本薬学会第133年会 

    Presentation date: 2013.03

  • 炎症誘発結晶の直線複屈折の定量測定;尿酸一ナトリウム水和物

    第60回応用物理学会春季学術講演会 

    Presentation date: 2013.03

  • コラーゲン異方性膜のG-HAUPによる光学的異方性及び光学活性の測定

    第60回応用物理学会春季学術講演会 

    Presentation date: 2013.03

  • リチウム二次電池用電析Si-O-C負極の充放電特性に及ぼす析出電位の影響

    電気化学会第80回大会 

    Presentation date: 2013.03

  • The E3 ubiquitin ligase component cereblon is recruited to aggresome by proteasome stress

    Toru Asahi, Naoya Sawamura

    NeuroScience2013 

    Presentation date: 2013

  • Arctic mutant Aβ affects CHRNA7’s functions through specific binding

    Toru Asahi, Naoya Sawamura

    NeuroScience2013 

    Presentation date: 2013

  • Measurement of Optical Properties of Nickel Sulfate Hexahydrate with Genaralized HAUP

    Kazuhiko Ishikawa, Masahito Tanaka, Toru Asahi

    25th International Symposium on Chirality 2013 

    Presentation date: 2013

  • デルタロドプシンのミトコンドリア特異的発現:パーキンソン病治療への応用

    第85回日本生化学会大会 

    Presentation date: 2012.12

  • 各種酸化ストレスに対するサリドマイドの神経細胞死抑制効果の解析

    第85回日本生化学会大会 

    Presentation date: 2012.12

  • 分光学・理論計算を用いたキラルなサリドマイド代謝における分子構造と挙動の解析

    第6回分子科学討論会2012東京 

    Presentation date: 2012.09

  • Aβ凝集時の足場としてのCHRNA7の役割

    日本薬学会 第132年会(札幌) 

    Presentation date: 2012.03

  • サリドマイドとそのエナンチオマーによる神経保護作用の分子メカニズム

    日本薬学会 第132年会(札幌) 

    Presentation date: 2012.03

  • 結晶誘発性炎症の物理化学的性質:尿酸一ナトリウム一水和物

    第59回応用物理学関係連合講演会 

    Presentation date: 2012.03

  • ポリL-及びDL-乳酸ナノシートの微細構造解析

    第59回応用物理学関係連合講演会 

    Presentation date: 2012.03

  • グリシン結晶のAbsolute Chirality:絶対構造と光学活性の関係

    The 3rd Symposium on Chiral Science &amp; Technology 

    Presentation date: 2012.02

  • ポリL-乳酸及びポリDL-乳酸ナノシートの微細構造解析

    The 3rd Symposium on Chiral Science &amp; Technology 

    Presentation date: 2012.02

  • 高い異方性を持つコラーゲンシートの光学的性質

    The 3rd Symposium on Chiral Science &amp; Technology 

    Presentation date: 2012.02

  • ヒト血清アルブミンとサリドマイドの相互作用解析

    The 3rd Symposium on Chiral Science &amp; Technology 

    Presentation date: 2012.02

  • パーキンソン病モデル細胞におけるサリドマイドの神経細胞死抑制効果

    The 3rd Symposium on Chiral Science &amp; Technology 

    Presentation date: 2012.02

  • The Absolute Chirality of γ-Glycine

    Kazuhiko Ishikawa, Masahito Tanaka, Tsuneomi Kawasaki, Kenso Soai, Motoo Shiro, Akiko Sekine, Meir Lahav, Toru Asahi

    11th Symposium on Chemical Approaches to Chirality 

    Presentation date: 2012

  • The Absolute Chirality of γ-Glycine Crystal

    Kazuhiko Ishikawa, Masahito Tanaka, Tsuneomi Kawasaki, Kenso Soai, Motoo Shiro, Akiko Sekine, Meir Lahav, Toru Asahi

    The 5th Symposium on Molecular Chirality of Chinese Chemical Society & International Chiral Meeting 

    Presentation date: 2012

  • Analysis of Microstructure of Nanosheets Composed of Poly (L-Lactic Acid) or Poly (DL-Lactic Acid)

    Akihiro Udagawa, Yuko Kawamoto, Shinji Takeoka, Toru Asahi

    The 5th Symposium on Molecular Chirality of Chinese Chemical Society & International Chiral Meeting 

    Presentation date: 2012

  • The optical activity of γ-glycine crystal

    K. Ishikawa, M. Tanaka, T. Kawasaki, K. Soai, M. Shiro, T. Asahi

    Symposium on Molecular Chirality ASIA 2012 

    Presentation date: 2012

  • Spectroscopic and theoretical analyses of molecular behavior in thalidomide metabolism relecant to chirality

    Y. Ogino, K. Otogawa, M. Tanaka, N. Shibata, T. Asahi

    Symposium on Molecular Chirality ASIA 2012 

    Presentation date: 2012

  • 高い異方性を持つコラーゲンシートのキラル光学的性質

    第1回 CSJ化学フェスタ -2011世界化学年記念大会- 

    Presentation date: 2011.11

  • γ-グリシン結晶の絶対構造決定

    第1回 CSJ化学フェスタ -2011世界化学年記念大会- 

    Presentation date: 2011.11

  • ポリL-乳酸及びポリDL-乳酸ナノシートの物性評価

    第1回 CSJ化学フェスタ -2011世界化学年記念大会- 

    Presentation date: 2011.11

  • キラル分光学的手法によるサリドマイドとその加水分解産物の分子挙動の解析

    第1回 CSJ化学フェスタ -2011世界化学年記念大会- 

    Presentation date: 2011.11

  • ポリ-L-乳酸ナノシートの分子透過能の解析

    第1回 CSJ化学フェスタ -2011世界化学年記念大会- 

    Presentation date: 2011.11

  • デルタロドプシンのミトコンドリア特異的発現による哺乳類細胞でのエネルギー産生

    第1回 CSJ化学フェスタ -2011世界化学年記念大会- 

    Presentation date: 2011.11

  • サリドマイドのエナンチオ選択的な神経保護作用の分子メカニズムの解明

    第1回 CSJ化学フェスタ -2011世界化学年記念大会- 

    Presentation date: 2011.11

  • ポリ-L-乳酸ナノシートの分子透過能の解析

    第60回 高分子学会年次会 

    Presentation date: 2011.05

  • サリドマイドのエナンチオ選択的な神経細胞死抑制効果

    シンポジウム モレキュラー・キラリティー 

    Presentation date: 2011.05

  • 高異方性コラーゲンシートの光学的性質

    シンポジウム モレキュラー・キラリティー 

    Presentation date: 2011.05

  • ポリL-乳酸及びポリDL-乳酸ナノシートの微細構造解析

    シンポジウム モレキュラー・キラリティー 

    Presentation date: 2011.05

  • プロリン・ヒドロキシプロリンの円二色性分光による分子構造解析

    シンポジウム モレキュラー・キラリティー 

    Presentation date: 2011.05

  • (S)-サリドマイドと(RS)-サリドマイドの溶媒和物形成における違い

    シンポジウム モレキュラー・キラリティー 

    Presentation date: 2011.05

  • サリドマイド及びその類似体のキラル光学的研究

    シンポジウム モレキュラー・キラリティー 

    Presentation date: 2011.05

  • グリシン結晶の絶対構造:絶対配置と旋光能の関係

    シンポジウム モレキュラー・キラリティー 

    Presentation date: 2011.05

  • Absolute structure and optical activity of gamma-glycine crystal

    K. Ishikawa, A. Takanabe, T. Suzuki, M. Tanaka, T. Kawasaki, K. Soai, T. Asahi

    The 23rd International Symposium on Chiral Discrimination (Chirality 2011) 

    Presentation date: 2011

  • Elucidation of the enantioselective pharmacological effect of thalidomide in neuroprotection

    N. Sawamura, H. Yamada, T. Asahi

    The 23rd International Symposium on Chiral Discrimination (Chirality 2011) 

    Presentation date: 2011

  • Chiroptical study on thalidomide hydrolysis and chiral inversion in solution

    Y. Ogino, M. Tanaka, T. Suzuki, N. Shibata, T. Asahi

    The 23rd International Symposium on Chiral Discrimination (Chirality 2011) 

    Presentation date: 2011

  • The new technique of ATP synthesis in cultured mammalian cells: mitochondria-specific expression of deltarhodopsin

    T. Wada, K. Hara, T. Asahi, N. Sawamura

    The 5th International Workshop on Approaches to Single-Cell Analysis 

    Presentation date: 2011

  • キラルおよびラセミ結晶中のサリドマイド分子の二量体構造

    第4回 分子科学討論会 

    Presentation date: 2010.09

  • 分光学的手法による溶液状態でのサリドマイド分子挙動の解析

    第4回 分子科学討論会 

    Presentation date: 2010.09

  • サリドマイド結晶中における二量体構造の評価

    シンポジウム モレキュラー・キラリティー 

    Presentation date: 2010.07

  • サリドマイドとそのエナンチオマーによる神経保護作用の解析

    シンポジウム モレキュラー・キラリティー 

    Presentation date: 2010.07

  • γ-Glycineの結晶構造と光学活性

    シンポジウム モレキュラー・キラリティー 

    Presentation date: 2010.07

  • ポリ(L)乳酸からなるナノシートの微細構造と機能の関係

    シンポジウム モレキュラー・キラリティー 

    Presentation date: 2010.07

  • 円二色性および紫外可視吸収分光法を用いたThalidomide加水分解のpHおよび温度依存性

    シンポジウム モレキュラー・キラリティー 

    Presentation date: 2010.07

  • アキラルグリシン硫酸塩が形成するキラル強誘電体結晶を不斉開始剤とする不斉自己触媒反応

    日本化学会 第90春季年会(2010) 

    Presentation date: 2010.03

  • 有機ナノチューブの構造特性と細胞増殖能

    第58回高分子討論会 

    Presentation date: 2009.09

  • 下地層からのCu拡散を利用したSm-Co層のグラニュラ化

    日本化学会 第3回関東支部大会(2009) 

    Presentation date: 2009.09

  • 置換めっき法を用いたPd核形成によるSmCo5垂直磁化膜の磁気特性および記録再生特性の改善

    第33回 日本磁気学会学術講演会 

    Presentation date: 2009.09

  • 下地層の拡散を利用したSm-Co 層グラニュラ膜の分離度の向上

    第33回 日本磁気学会学術講演会 

    Presentation date: 2009.09

  • 一般型高精度万能旋光計による異方性固体物質のキラル光学特性の測定

    シンポジウム モレキュラー・キラリティー 

    Presentation date: 2009.05

  • SmCo5垂直磁気記録媒体の開発

    電子情報通信学会 磁気記録・情報ストレージ(MR)研究会(ハードディスクドライブおよび一般) 

    Presentation date: 2008.11

  • 下地層からのCu拡散を利用したSm-Co層のグラニュラ化

    第32回 日本磁気学会学術講演会 

    Presentation date: 2008.09

  • 次世代磁気記録媒体用FePtナノ粒子の開発

    電子情報通信学会 磁気記録・情報ストレージ(MR)研究会(PMRC特集) 

    Presentation date: 2007.11

  • Cを添加したSmCo5垂直磁化薄膜における記録再生特性と耐食性

    PMRC2007サテライトミーティング−次世代磁気記録材料・システムへの挑戦− 

    Presentation date: 2007.10

  • FePtナノキューブの熱処理によるL10規則化

    PMRC2007サテライトミーティング−次世代磁気記録材料・システムへの挑戦− 

    Presentation date: 2007.10

  • 無電解めっき法により作製した二層型軟磁性裏打ち層のノイズ特性

    PMRC2007サテライトミーティング−次世代磁気記録材料・システムへの挑戦− 

    Presentation date: 2007.10

  • 高磁気異方性垂直磁気記録媒体SmCo5の開発

    PMRC2007サテライトミーティング−次世代磁気記録材料・システムへの挑戦− 

    Presentation date: 2007.10

  • C導入によるSmCo5 垂直磁化膜の磁性粒子クラスター径低減

    第31回 日本応用磁気学会学術講演会 

    Presentation date: 2007.09

  • 新規磁気記録媒体用の立方状fcc-FePtナノ粒子の作製

    第31回 日本応用磁気学会学術講演会 

    Presentation date: 2007.09

  • アミノ酸結晶性膜作製法の開発

    モレキュラー・キラリティ 2007 -不斉の発生と増幅- 

    Presentation date: 2007.05

  • 強誘電体硫酸グリシン結晶の電界によるキラリティ反転

    モレキュラー・キラリティ 2007 -不斉の発生と増幅- 

    Presentation date: 2007.05

  • L-ホモシステイン自己組織化単分子膜修飾金電極における光学活性アミノ酸金属錯体の配位子交換反応

    モレキュラー・キラリティ 2007 -不斉の発生と増幅- 

    Presentation date: 2007.05

  • アミノ酸結晶膜の作製及びキラル光学的研究

    第54回応用物理学関係連合講演会 

    Presentation date: 2007.03

  • ホモシステイン単分子膜修飾金電極におけるカテキンの酸化還元のキラル選択性

    2006年 電気化学秋季大会 

    Presentation date: 2006.09

  • 無電解めっき法による二層型CoNiFeB軟磁性裏打ち層の作製

    第30回 日本応用磁気学会学術講演会 

    Presentation date: 2006.09

  • 軟磁性裏打ち層を付与したSmCo5垂直二層膜の作製

    第30回 日本応用磁気学会学術講演会 

    Presentation date: 2006.09

  • 垂直磁化膜 Sm(Co, Cu)5 における元素別磁化過程

    第30回 日本応用磁気学会学術講演会 

    Presentation date: 2006.09

  • 高垂直磁気異方性Sm-Co薄膜に及ぼす熱処理の影響

    第30回 日本応用磁気学会学術講演会 

    Presentation date: 2006.09

  • TbCo/Pd垂直磁化多層膜の磁気円二色性のTbCo層厚依存性

    第30回 日本応用磁気学会学術講演会 

    Presentation date: 2006.09

  • Sm(Co, Cu)5垂直磁化膜の元素選択的ヒステリシス

    電子情報通信学会 磁気記録・情報ストレージ研究会 

    Presentation date: 2006.07

  • X線磁気円二色性吸収分光によるDyxCo100-x垂直磁化膜の研究

    電子情報通信学会 2006総合大会 

    Presentation date: 2006.03

  • 無電解Pd/CoNiFeB下地層を用いたCo/Pd多層膜媒体の作製

    電子情報通信学会 2006総合大会 

    Presentation date: 2006.03

  • アミノ酸単結晶薄膜のキラル光学特性の評価

    第53回応用物理学関係連合講演会 

    Presentation date: 2006.03

  • L-ホモシステイン修飾Au電極におけるキラル配位子交換の電気化学的キラルセンシングへの応用

    日本化学会 第86春季年会(2006) 

    Presentation date: 2006.03

  • G-HAUPを用いたRh6G/K4Nb6O17層間化合物のキラル光学的研究

    日本化学会 第86春季年会(2006) 

    Presentation date: 2006.03

  • 無電解CoNiFeB薄膜の軟磁気特性に及ぼす析出速度の影響

    表面技術協会 第113回講演大会 

    Presentation date: 2006.03

  • SmCo5垂直磁化膜の磁気特性と構造

    日本応用磁気学会 第15回ナノマクネティックス専門研究会 

    Presentation date: 2006.02

  • 垂直磁化薄膜DyxCo100-xの硬X線MCDの磁場依存性

    第19回 日本放射光学会年会・放射光科学合同シンポジウム 

    Presentation date: 2006.01

  • ナノ構造制御による次世代垂直磁気記録媒体の創製

    未踏科学技術協会 磁性材料研究会21 第5回講演会 

    Presentation date: 2005.11

  • 高分解能オージェ電子分光法を用いたSm-Co垂直磁化膜のナノ界面解析

    第46回 真空に関する連合講演会 

    Presentation date: 2005.11

  • 色素包接層間化合物結晶KNO(化学式)のキラル光学的研究

    日本物理学会 2005年秋季大会 

    Presentation date: 2005.09

  • アミノ酸薄膜のキラル光学的研究

    第66回応用物理学会学術講演会 

    Presentation date: 2005.09

  • ホモシステイン単分子膜修飾金電極におけるDOPAのキラル選択的酸化還元−DOPA濃度およびpHの影響

    2005年 電気化学秋季大会 

    Presentation date: 2005.09

  • 有機単分子膜を修飾した軟磁性下地層上のCo/Pd多層膜の磁気特性

    第29回 日本応用磁気学会学術講演会 

    Presentation date: 2005.09

  • SmCo5垂直磁化膜の磁区構造解析

    第29回 日本応用磁気学会学術講演会 

    Presentation date: 2005.09

  • UHVスパッタリングによるSmCo5垂直磁化膜の作製

    第29回 日本応用磁気学会学術講演会 

    Presentation date: 2005.09

  • Cuを添加したSm-Co垂直磁化膜の薄膜微細構造

    第29回 日本応用磁気学会学術講演会 

    Presentation date: 2005.09

  • 置換析出金属核を中間層としたTbFeCo垂直記録媒体の磁気特性

    第29回 日本応用磁気学会学術講演会 

    Presentation date: 2005.09

  • アゾベンゼン誘導体をゲストとしたニオブ酸カリウム層間化合物結晶のキラル光学的研究

    モレキュラー・キラリティ 2005 -キラリティの創出と制御- 

    Presentation date: 2005.06

  • システインおよびホモシステイン単分子膜修飾金電極におけるDOPAの酸化還元挙動の比較

    2005年 電気化学会第72回大会 

    Presentation date: 2005.04

  • ホモシステイン単分子膜修飾金電極におけるDOPAの酸化還元のキラル選択性

    2005年 電気化学会第72回大会 

    Presentation date: 2005.04

  • 色素包接層間化合物K4Nb6O17のキラル光学的研究

    第52回応用物理学関係連合講演会 

    Presentation date: 2005.03

  • 色素包接K4Nb6O17結晶のキラル光学的研究

    日本化学会 第85春季年会(2005) 

    Presentation date: 2005.03

  • 置換析出法により形成したPdクラスタシードを有するCo/Pd多層膜媒体

    電子情報通信学会 磁気記録(MR)研究会 

    Presentation date: 2005.01

  • アミノ酸固相のSR 分光の現状と課題

    第18回 日本放射光学会年会・放射光科学合同シンポジウム 

    Presentation date: 2005.01

  • "CoFeNiB無電解めっき軟磁性膜のXAS/MCD

    第18回 日本放射光学会年会・放射光科学合同シンポジウム 

    Presentation date: 2005.01

  • 垂直磁化膜DyxCo1-xのスペリ磁性と磁気モーメント

    第18回 日本放射光学会年会・放射光科学合同シンポジウム 

    Presentation date: 2005.01

  • SmCo5合金の垂直磁化膜の開発

    日本応用磁気学会 第11回ハイブリッド記録専門研究会 

    Presentation date: 2004.11

  • 色素添加層間化合物K4Nb6O17の直線2色性の発現

    第65回応用物理学会学術講演会 

    Presentation date: 2004.09

  • 無電解めっき法による垂直二層膜媒体用CoNiFeB軟磁性裏打ち層の作製

    表面技術協会 第110回講演大会 

    Presentation date: 2004.09

  • 軟X線磁気円二色性によるDyxCo1-xの元素別磁気モーメント

    第28回 日本応用磁気学会学術講演会 

    Presentation date: 2004.09

  • SmCo5垂直磁化膜の磁気特性に及ぼすCu添加の効果

    第28回 日本応用磁気学会学術講演会 

    Presentation date: 2004.09

  • Cu/Ti下地層の適用によるSmCo5垂直磁化膜の高磁気異方性化

    第28回 日本応用磁気学会学術講演会 

    Presentation date: 2004.09

  • TbCo/Pd垂直磁気多層膜の磁気特性

    第28回 日本応用磁気学会学術講演会 

    Presentation date: 2004.09

  • 電気化学プロセスによるPd/CoNiFeB下地層の作製

    第28回 日本応用磁気学会学術講演会 

    Presentation date: 2004.09

  • 垂直磁気異方性を有するSmCo5薄膜の作製

    電子情報通信学会 2004総合大会 

    Presentation date: 2004.03

  • 湿式法により形成したPdシードを有するCo/Pd多層膜媒体の作製

    電子情報通信学会 2004総合大会 

    Presentation date: 2004.03

  • SmCo5垂直磁化膜の磁気特性に及ぼすCu下地層の影響

    電子情報通信学会 2004総合大会 

    Presentation date: 2004.03

  • HAUPによるキラル薄膜の分光学的研究

    第51回応用物理学関係連合講演会 

    Presentation date: 2004.03

  • 自己組織化単分子膜修飾金基板上でのロイシン結晶化とそのキラル選択性

    日本化学会 第84春季年会(2004) 

    Presentation date: 2004.03

  • Tb-Coアモルファス薄膜のTb-M4, 5吸収端におけるXAS-MCDの角度依存性

    第17回 日本放射光学会年会・放射光科学合同シンポジウム 

    Presentation date: 2004.01

  • MCD測定の[Co/Pd]n多層垂直磁化膜磁性に関する研究への適応

    第17回 日本放射光学会年会・放射光科学合同シンポジウム 

    Presentation date: 2004.01

  • ウェットプロセスを用いた垂直二層膜媒体用下地層の作製

    電子情報通信学会 MR研究会 

    Presentation date: 2003.11

  • 二次元不斉自己組織化単分子層膜の構造と機能

    第52回高分子討論会 

    Presentation date: 2003.09

  • Co−L2,3 吸収端磁気円二色性測定を用いた[Co/Pd]n多層垂直磁化膜の研究

    第27回 日本応用磁気学会学術講演会 

    Presentation date: 2003.09

  • [Co/Pd]n垂直二層膜媒体用Pd/Siシード層の膜厚低減

    第27回 日本応用磁気学会学術講演会 

    Presentation date: 2003.09

  • ウェットプロセスによる垂直二層膜媒体用シード層の作製

    第27回 日本応用磁気学会学術講演会 

    Presentation date: 2003.09

  • TbFeCo垂直磁化膜の磁気異方性エネルギーと軌道角運動量の相関

    第27回 日本応用磁気学会学術講演会 

    Presentation date: 2003.09

  • Si単結晶ディスク基板を用いた湿式法による垂直二層膜媒体用軟磁性裏打ち層の開発

    第27回 日本応用磁気学会学術講演会 

    Presentation date: 2003.09

  • 無電解めっき法による軟磁性裏打ち層を用いた垂直二層膜媒体の開発

    電子情報通信学会 2003総合大会 

    Presentation date: 2003.03

  • Pd/Siシード層による[Co/Pd]n-CoZrNb垂直二層膜媒体の微細構造制御とノイズ低減

    電子情報通信学会 2003総合大会 

    Presentation date: 2003.03

  • CoB/Pd多層膜の磁気特性に及ぼすスパッタリング条件の影響

    電子情報通信学会 2003総合大会 

    Presentation date: 2003.03

  • TbFeCoアモルファス垂直磁化膜のTb-M4,5吸引端における磁気円2色性の角度依存性

    2003年春季 第50回応用物理学関係連合講演会 

    Presentation date: 2003.03

  • a-TbFeCo垂直磁化膜の磁気異方性エネルギーとCo及びFe-3d電子の軌道角運動量の相関

    2003年春季 第50回応用物理学関係連合講演会 

    Presentation date: 2003.03

  • エチレンジアミンヨウ化コバルト錯体単結晶のキラル光学的研究

    日本化学会 第83春季年会(2003) 

    Presentation date: 2003.03

  • ロイシンのキラルおよびラセミ単結晶の結晶学的研究

    日本化学会 第83春季年会(2003) 

    Presentation date: 2003.03

  • 自己組織化単分子膜上におけるロイシン結晶成長に及ぼす基板の影響

    日本化学会 第83春季年会(2003) 

    Presentation date: 2003.03

  • トリプタミン−カルボン酸有機塩結晶の旋光能

    日本化学会 第83春季年会(2003) 

    Presentation date: 2003.03

  • Co/Pd多層膜の磁気特性に及ぼすスパッタ成膜条件の影響

    第14回 日本MRS学術シンポジウム 

    Presentation date: 2002.12

  • シード層によるCo/Pd多層垂直磁気記録媒体のノイズ低減

    応用磁気学会マイクロ磁区専門研究会 

    Presentation date: 2002.12

  • 自己組織化単分子膜上におけるアミノ酸のキラル選択的結晶成長

    日本化学会 第82秋季年会(2002) 

    Presentation date: 2002.09

  • 軸不斉化合物自己組織化単分子膜のキラル認識場としての評価:サリドマイドのキラル選択的吸着

    日本化学会 第82秋季年会(2002) 

    Presentation date: 2002.09

  • [Co/Pd]n垂直磁気記録媒体の磁気特性に及ぼすPd/Siシード層作製条件の影響

    第26回 日本応用磁気学会学術講演会 

    Presentation date: 2002.09

  • アモルファスC, Si膜下地層によるCo/Pd多層垂直磁化膜の改質

    第26回 日本応用磁気学会学術講演会 

    Presentation date: 2002.09

  • Co/Pd多層膜の粒子間交換相互作用に及ぼす成膜プロセスの影響

    第26回 日本応用磁気学会学術講演会 

    Presentation date: 2002.09

  • 記録層への非磁性層導入による[Co/Pd]n垂直磁気記録媒体の低ノイズ化

    電子情報通信学会 MR研究会 

    Presentation date: 2002.06

  • 垂直二層膜媒体への応用を目的としたCo/Pd多層垂直媒体用Pdシード層の開発

    電子情報通信学会 2002総合大会 

    Presentation date: 2002.03

  • 非磁性中間層付与によるCo/Pd多層垂直磁気記録媒体の低ノイズ化

    電子情報通信学会 2002総合大会 

    Presentation date: 2002.03

  • HAUPによるキラル結晶の旋光能の測定:トリプタミン カルボン酸系ヘリックス型結晶

    第8回有機結晶シンポジウム 

    Presentation date: 2002.03

  • 軸不斉化合物自己組織化単分子膜のキラル認識場としての評価:フェニルアラニンのキラル選択的吸着

    日本化学会 第81春季年会(2002) 

    Presentation date: 2002.03

  • 自己組織化単分子膜上におけるグルタミン酸固定および結晶成長

    日本化学会 第81春季年会(2002) 

    Presentation date: 2002.03

  • 遷移金属・貴金属系磁気記録材料の磁気物性と磁区構造 -イントロダクション-

    日本応用磁気学会 第122回研究会・化合物新磁性材料専門研究会 

    Presentation date: 2002.01

  • Microstructure and Magnetic Properties of Co/Pd Multilayered thin films with C or Si seedlayer

    Presentation date: 2002.01

  • 高密度磁気記録用Co/Pd多層膜の微細構造制御

    第45回 日本学術会議材料研究連合講演会 

    Presentation date: 2001.09

  • 軸不斉化合物自己組織化単分子膜上へのキラル選択的アミノ酸吸着挙動

    2001年 電気化学会第68回秋季大会 

    Presentation date: 2001.09

  • 無電解めっき法によるCoNiP磁性ドット媒体の作製

    第25回 日本応用磁気学会学術講演会 

    Presentation date: 2001.09

  • Co/(Pd,Pt)多層膜/高Bs軟磁性薄膜垂直二層膜媒体の新規作成手法の開発 -無電解めっき法によるCoNiFeB軟磁性膜の裏打ち層への適用-

    第25回 日本応用磁気学会学術講演会 

    Presentation date: 2001.09

  • CおよびSi下地層を有するCo/Pd多層垂直磁気記録媒体の微細構造解析

    第25回 日本応用磁気学会学術講演会 

    Presentation date: 2001.09

  • [Co/Pd]n/X(X : C, Si, Pd)系垂直磁気記録媒体の磁気異方性、異方性磁界、保磁力と磁化反転機構

    第25回 日本応用磁気学会学術講演会 

    Presentation date: 2001.09

  • Co/(Pd,Pt)多層垂直磁気記録媒体の磁気特性と電磁変換特性

    第25回 日本応用磁気学会学術講演会 

    Presentation date: 2001.09

  • Pd/Si下地層を有するCo/Pd多層垂直磁気記録媒体の作製

    第25回 日本応用磁気学会学術講演会 

    Presentation date: 2001.09

  • 軸不斉化合物自己組織化単分子膜修飾QCMによる光学活性アミノ酸吸着挙動の評価

    2001年 電気化学会第68回春季大会 

    Presentation date: 2001.04

  • ハウプによるfresnoite(Bi2Si2TiO8)の相転移の光学的研究

    日本物理学会 第56回年次大会 

    Presentation date: 2001.03

  • アモルファス下地層を有するCo/Pd垂直磁気多層膜の微細構造と磁気特性

    日本物理学会 第56回年次大会 

    Presentation date: 2001.03

  • 軸不斉化合物自己組織化単分子膜上への光学活性アミノ酸吸着挙動

    日本化学会 第79春季年会(2001) 

    Presentation date: 2001.03

  • HAUPによる4-クロロ安息香酸-トリプタミン結晶の旋光能の測定

    日本化学会 第79春季年会(2001) 

    Presentation date: 2001.03

  • アモルファス下地層Co/Pd多層垂直磁気記録媒体の磁気特性と微細構造

    日本応用磁気学会 研究会第118回 100Gb/in2時代の磁気記録-新しいアプリケーションと技術展開-(第71回マイクロ磁区専門研究会と共催) 

    Presentation date: 2001.02

  • Si単結晶基板の表面処理による磁性薄膜の磁気特性制御

    表面技術協会 第102回講演大会 

    Presentation date: 2000.09

  • カーボン下地層を有するCo/Pd多層垂直磁気記録媒体の作製

    第24回 日本応用磁気学会学術講演会 

    Presentation date: 2000.09

  • CoCrPtTa/NiCr媒体における膜厚方向の微細構造変化

    第24回 日本応用磁気学会学術講演会 

    Presentation date: 2000.09

  • MFMによる垂直磁気記録媒体の磁化状態の解析手法の検討

    第24回 日本応用磁気学会学術講演会 

    Presentation date: 2000.09

  • アモルファスSi中間層を用いた垂直面内複合型媒体の作製

    第24回 日本応用磁気学会学術講演会 

    Presentation date: 2000.09

  • CoCrPtTa/NiCr/Ti媒体におけるTi下地層へのN2添加効果

    電子情報通信学会 2000総合大会 

    Presentation date: 2000.03

  • CoCrPtTa/CoCr/Ge単層垂直媒体の記録再生特性に及ぼすGe下地層厚の影響

    電子情報通信学会 2000総合大会 

    Presentation date: 2000.03

  • リングヘッド/垂直単層磁気記録媒体系における記録ヘッドパラメータの影響

    電子情報通信学会 2000総合大会 

    Presentation date: 2000.03

  • Fresnoite Ba2TiSi2O8の光学活性と相転移

    日本結晶学会年会 1999年 

    Presentation date: 1999.11

  • リングヘッド/垂直単層磁気記録媒体系におけるトラック端部磁化状態の解析

    第23回 日本応用磁気学会学術講演会 

    Presentation date: 1999.10

  • Ge下地層を有する垂直単層磁気記録媒体の作製

    第23回 日本応用磁気学会学術講演会 

    Presentation date: 1999.10

  • Co73Cr18Pt6Ta3/Co60Cr40/C単層垂直磁気記録媒体の非磁性Co60Cr40中間層の効果

    第23回 日本応用磁気学会学術講演会 

    Presentation date: 1999.10

  • CoCrPtTa/Ni及びCoCrPtTa/Ni/Ti垂直面内複合型媒体の作製

    第23回 日本応用磁気学会学術講演会 

    Presentation date: 1999.10

  • 垂直単層磁気記録媒体における結晶配向分散の効果

    第23回 日本応用磁気学会学術講演会 

    Presentation date: 1999.10

  • NiCr磁性下地層を付与した垂直面内複合型媒体の作製

    電子情報通信学会 1999総合大会 

    Presentation date: 1999.03

  • 単層垂直磁気記録媒体の磁気特性に及ぼすカーボン下地層厚の効果

    電子情報通信学会 1999総合大会 

    Presentation date: 1999.03

  • リゾチーム単結晶の旋光能

    日本結晶学会年会 1998年 

    Presentation date: 1998.11

  • スパッタ法による垂直面内複合型媒体の作製

    第22回 日本応用磁気学会学術講演会 

    Presentation date: 1998.09

  • 垂直記録孤立波磁化のMR再生特性の解析解

    第22回 日本応用磁気学会学術講演会 

    Presentation date: 1998.09

  • 長手記録孤立波磁化のMRヘッド再生応答の解析解

    第22回 日本応用磁気学会学術講演会 

    Presentation date: 1998.09

▼display all

Specific Research

  • 強誘電性結晶硫酸トリグリシンのキラリティ制御機構の解明

    2018  

     View Summary

    キラル分子であるL体およびD体のアラニン、乳酸、スレオニン、セリンを硫酸トリグリシン(Triglycine sulfate ; TGS)にドープした結晶において、アラニンドープTGS(alanine-doped TGS ; ATGS)のみ、アラニンのキラリティによってTGS結晶のキラリティが偏ることを見出した。また、ATGSの結晶構造を決定し、アラニンがTGS結晶のキラリティを決定する分子と置換する可能性があることが分かり、アラニンのキラリティによってTGS結晶のキラリティが制御される機構の解明の手掛かりを得た。

  • 異方性二次元キラルナノ構造体の可逆・非可逆光学現象の検証

    2016   成島哲也, 中川鉄馬

     View Summary

    二次元で鏡面対称 (線対称) を有さないナノメートルサイズの形状を持つ「S」などの構造を異方的に整列させた集合体「異方性二次元キラルナノ構造体 (2D-CNS)」が、直線偏光の偏光面を回転させる性質「旋光性」や楕円偏光化させる性質「円二色性」を示すか否かを我々が独自に開発してきた「高精度万能旋光計 (G-HAUP)」を用いて可逆あるいは非可逆現象の検証を含め調べ、その発現起因 (空間反転対称性の破れ、時間反転対称性の破れ) にまで踏み込んで考察した。本研究成果は、光と物質の相互作用過程に、試料の構造や形状などの二次元的な非対称性がどのように関与しているのかを理解することにつながる。

  • 銅酸化物高温超伝導体Bi2Sr2CaCu2O8+xの光学的性質と対称性の破れ

    2016   松田梓, 中川鉄馬, 篠元輝

     View Summary

    最適ドープ・アンダードープのBi系銅酸化物高温超伝導体Bi2Sr2CaCu2O8+δ (Bi2212) 単結晶をフローティング法を用いて育成し,その極薄試料をそのc軸方向の劈開性を利用して作成した。また,常温における光学活性,自然円二色性,Faraday回転,磁気円二色性,直線複屈折,直線二色性の波長依存性を高精度万能旋光計 (G-HAUP) により測定した。それら符号と大きさを比較することにより,銅酸化物高温超伝導体における超伝導発現機構の解明につながると考えられる擬ギャップ相における空間・時間反転対称性の破れの存否を直接的に検証することが可能となった。

  • 異方性物質の磁気キラル光学的研究

    2014   Garcia Villora, 島村清史

     View Summary

    &nbsp;Faradayrotator single-crystals have attracted much attention in the field ofmagneto-optics due to their broad applications such as optical isolators,optical modulators, and beam splitters.&nbsp;Rare-earth (RE) fluorides (CeF3, PrF3 and LiREF4)single-crystals have been investigated due to their unique transmittance in theUV wavelength region.&nbsp; Themagneto-optical effects of the RE ions are known to be caused by the intraionicparity allowed electric dipole transition between the 4fN and 4fN-15d1configurations. These transitions are close to the absorption cut-off in thewidely transparent fluorides, so that these achieve outstanding Verdetconstants in the UV wavelength region.&nbsp;&nbsp;&nbsp;Accurate Faraday rotationmeasurements have been carried out along the optical c-axis in order to avoid the linear birefringence.&nbsp; However, to investigate the optical and magnetic properties of the REfluorides in more detail, measurements along the perpendicular direction arerequired.&nbsp; In this study, the wavelength dependencesof the linear and circular birefringences of CeF3 single-crystalalong the a-axis were measured withthe Generalized-High Accuracy Universal Polarimeter (G-HAUP).

  • 精神神経疾患の診断と病態解明を目指したバイオセンサの開発

    2013  

     View Summary

    特定課題B「精神神経疾患の診断と病態解明を目指したバイオセンサの開発」では、FETバイオセンサを用いて、センサ検出部に修飾されている有機薄膜とAmyloid &szlig;タンパク質(Amyloid &szlig; protein; Aβ)との相互作用に基づいた検出機構について、先端電位変化検出手法を用いて解明する事を目的として研究を行った。さらに、精神神経疾患の診断へ応用できるバイオセンサの実用化目指すとともに、確立したバイオセンサを用いて、精神神経疾患モデル神経細胞や患者サンプルでのアミロイド&szlig;蛋白の分泌量を測定し、病態を解明することを目指して研究を行った。本研究では、クロスβ構造を有するアミロイド凝集体と特異的な相互作用を示すコンゴーレッドでゲート表面を修飾したFETによるAβ(1-42)凝集体の検出を試みた。Aβ(1-42)の検出はFET特性(ゲート電圧-ドレイン電流特性)の閾値電圧シフトとして評価した。Aβ(1-42)のモノマーを数日インキュベートして得た試料では、凝集体を形成した場合にのみFET応答が観測された。また、Aβ(1-42)とその亜種であるAβ(1-40)に対する応答を比較したところ、Aβ(1-42)検出が可能なインキュベート日数であっても、凝集能の低いAβ(1-40)にはFET応答は観測されず、コンゴーレッド修飾FETのAβ凝集体への特異的な応答が示唆された。本研究成果は今年2月にChemical Communications に掲載され、日本経済新聞にも取り上げられた。参考文献Hideshima, S., Kobayashi, M., Wada, T., Kuroiwa, S., Nakanishi, T., Sawamura, N., Asahi T., Osaka, T.A label-free electrical assay of fibrous amyloid β based on semiconductor biosensing. Chemical Communications 50, 3476-3479 (2014)2014.3.25日本経済新聞夕刊 014ページ 「アルツハイマー病の原因物質,短時間で検出 早大が開発」

  • キラル・磁気光学ハイブリッド顕微鏡の開発

    2007   田中真人

     View Summary

    物質のキラリティの研究は、アミノ酸、タンパク質、DNAなどの生体物質の構造と機能性の関係の解明、薬剤の効用と副作用の研究などに有用となる物質科学における緊要な学際的研究である。われわれは、直線複屈折、直線2色性、円複屈折、円2色性を同時に測定できる光学測定法(拡張HAUP法)を開発し、2それら異方的光学物理量の分光学的測定及び温度依存性の測定を可能とした「一般型高精度万能旋光計」(Generalized-HAUP、略称、G-HAUP)の開発に成功した。本研究では、その測定原理をイメージング技術に応用して、新しい顕微鏡「キラル・磁気光学ハイブリッド顕微鏡」を創設ために不可欠な光学系の改良ならびに測定プログラムの開発やその実証に必要な実験を遂行することとした。さらに、シンクロトロン放射光を用いた「キラル・磁気光学ハイブリッド顕微鏡」の開発への試験的な研究に着手することとした。まずは、キラル光学効果の高分解能分光測定及び2次元イメージングのできる「透過型高分解能キラリティ顕微鏡」を試作するため、G-HAUPの光学系及びその駆動系、試料台、検出器、ノイズ低減機構、測定及びデータ解析プログラムを改良した。次いで、その新しい光学系と測定プログラムを用いて、サリドマイドのキラル反転機構の解明に資するキラル光学的研究を行った。サリドマイドはキラルな分子構造を有するきわめて有用な薬剤であるが,溶液状態ではR体からS体,S体からR体へキラル反転することが指摘され、その機構は未だ十分理解されていない。一方、サリドマイドのキラル光学性質を測定し、その結果の正当性を確保するためには、サリドマイドのキラル結晶の構造を決定することが重要である。そこで、まず、我々はこれまで明らかとなっていないサリドマイドのキラル結晶につき、X線回折法を用いて構造解析した。サリドマイドの結晶はキラルな点群C2となり、2つのサリドマイド分子が環状水素結合して安定な構造を有していることが明らかとなった。さらに,G-HAUPを用いてサリドマイドのキラル結晶の光学的性質の波長依存性を調べたところ、再現性を確認する必要はあるものの、直線複屈折、直線2色性、円複屈折、円2色性の異常を見い出すことができた。

▼display all

 

Syllabus

▼display all