Researcher Database

OHARA, Keishi

FacultyGraduate School of Science and Engineering Engineering for Production and Environment
PositionProfessor
Last Updated :2019/08/20

Researcher Profile and Settings

Profile and Settings

Name

  • Name

    OHARA, Keishi

Profile & Settings

  • アバター画像URI

    https://researchmap.jp/?action=common_download_user&upload_id=107439

Affiliations

Affiliation & Job

  • Section

    Graduate School of Science and Engineering Chemistry and Biology
  • Job title

    Professor

Education, Etc.

Education

  • 19930400, 19960300, Kyoto University, Graduate School of Science, Department of Chemistry
  • 19870400, 19890300, Osaka University, Graduate School of Science, Inorganic and Physical Chemistry
  • 19830400, 19870300, Osaka University, Faculty of Science, Department of Chemistry

Degree

  • Doctor of Science

その他基本情報

Association Memberships

  • THE SOCIETY OF ELECTRON SPIN SCIENCE AND TECHNOLOGY
  • SOCIETY FOR FREE RADICAL RESEARCH JAPAN
  • THE SPECTROSCOPICAL SOCIETY OF JAPAN
  • THE CHEMICAL SOCIETY OF JAPAN

Committee Memberships

  • 20040400, 99990000
  • 20140500, 20160200
  • 20040400, 99990000, Spectroscopical Society of Japan, Organizer of Ehime Block, Spectroscopical Society of Japan

Academic & Professional Experience

  • 20150500, 99990000, Professor, Ehime University
  • 20070400, 20150400, Associate Professor, Ehime University
  • 20060400, 20070300, Senior Assistant Professor, Ehime University
  • 19960400, 20060300, Assistant Professor, Ehime University
  • 19960100, 19960400, Researcher (JSPS Research Fellowships for Young Scientists), Kyoto University

Research Activities

Research Areas, Etc.

Research Areas

  • Basic chemistry, Basic chemistry
  • Pharmacy, Physical pharmacy
  • Agricultural chemistry, Food science
  • Applied Chemistry, Functional materials chemistry

Research Interests

  • Photochemistry
  • Singlet Oxygen
  • Free Radical
  • Antioxidant
  • EPR
  • Near-Infrared spectroscopy
  • Spin-dynamics

Book, papers, etc

Published Papers

  • Synthesis, Structures, and Properties of Core-Expanded Azacoronene Analogue: A Twisted pi-System with Two N-Doped Heptagons, Oki Kosuke, Takase Masayoshi, Mori Shigeki, Shiotari Akitoshi, Sugimoto Yoshiaki, Ohara Keishi, Okujima Tetsuo, Uno Hidemitsu, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 20180822, [Refereed], 0002-7863, 10.1021/jacs.8b06079
  • Correlation among Singlet-Oxygen Quenching, Free-Radical Scavenging, and Excited-State Intramolecular-Proton-Transfer Activities in Hydroxyflavones, Anthocyanidins, and 1-Hydroxyanthraquinones, Nagaoka Shin-ichi, Bandoh Yuki, Nagashima Umpei, Ohara Keishi, JOURNAL OF PHYSICAL CHEMISTRY A, 20171026, [Refereed], 1089-5639, 10.1021/acs.jpca.7b07869
  • Dye-Sensitized Molecular Charge Transfer Complexes: Magnetic and Conduction Properties in the Photoexcited States of Ni(dmit)(2) Salts Containing Photosensitive Dyes, Yamamoto Ryoma, Yamamoto Takashi, Ohara Keishi, Naito Toshio, MAGNETOCHEMISTRY, 20170600, [Refereed], 2312-7481, 10.3390/magnetochemistry3020020
  • Direct Control of Spin Distribution and Anisotropy in Cu-Dithiolene Complex Anions by Light, Noma Hiroki, Ohara Keishi, Naito Toshio, INORGANICS, 20160600, [Refereed], 2304-6740, 10.3390/inorganics4020007
  • Template Synthesis of Decaphyrin without Meso-Bridges: Cyclo[10]pyrrole., Okujima T, Ando C, Agrawal S, Matsumoto H, Mori S, Ohara K, Hisaki I, Nakae T, Takase M, Uno H, Kobayashi N, Journal of the American Chemical Society, 20160600, [Refereed], 0002-7863, 10.1021/jacs.6b04941
  • Correlation between excited-state intramolecular proton-transfer and singlet-oxygen quenching activities in 1-(acylamino)anthraquinones, Shin Ichi Nagaoka, Hikaru Endo, Keishi Ohara, Umpei Nagashima, Journal of Physical Chemistry B, 20150200, [Refereed], 15206106, 10.1021/jp508355k
  • Scavenging rate constants of hydrophilic antioxidants against multiple reactive oxygen species, Yoshimi Sueishi, Masashi Hori, Misa Ishikawa, Keiko Matsu-ura, Erisa Kamogawa, Yusaku Honda, Masakazu Kita, Keishi Ohara, Journal of Clinical Biochemistry and Nutrition, 20140300, [Refereed], 09120009, 10.3164/jcbn.13-53
  • Capacitor-like behavior of molecular crystal β-DiCC[Ni(dmit) 2], Tomoko Saiki, Shigeki Mori, Keishi Ohara, Toshio Naito, Chemistry Letters, 20140100, [Refereed], 03667022, 10.1246/cl.140309
  • [Cu(dmit)2]2-building block for molecular conductors and magnets with photocontrollable spin distribution, Hiroki Noma, Keishi Ohara, Toshio Naito, Chemistry Letters, 20140100, [Refereed], 03667022, 10.1246/cl.140318
  • Giant photoconductivity in NMQ[Ni(dmit)2], Toshio Naito, Tomoaki Karasudani, Naoki Nagayama, Keishi Ohara, Kensuke Konishi, Shigeki Mori, Takahiro Takano, Yukihiro Takahashi, Tamotsu Inabe, Shota Kinose, Sadafumi Nishihara, Katsuya Inoue, European Journal of Inorganic Chemistry, 20140100, [Refereed], 14341948, 10.1002/ejic.201402035
  • Multi-emitting properties of hybrid Langmuir-Blodgett films of amphiphilic iridium complexes and the exfoliated nanosheets of saponite clay, Hisako Sato, Kenji Tamura, Keishi Ohara, Shin Ichi Nagaoka, New Journal of Chemistry, 20140100, [Refereed], 11440546, 10.1039/c3nj00879g
  • Synthesis of NIR-emitting O-chelated BODIPYs fused with benzene and acenaphthylene, Tetsuo Okujima, Yoichi Shida, Keishi Ohara, Yuya Tomimori, Motoyoshi Nishioka, Shigeki Mori, Takahiro Nakae, Hidemitsu Uno, Journal of Porphyrins and Phthalocyanines, 20140100, [Refereed], 10884246, 10.1142/S1088424614500503
  • Acenaphthylene-fused cyclo[8]pyrroles with intense near-IR-region absorption bands, Tetsuo Okujima, Chie Ando, John Mack, John Mack, Shigeki Mori, Ichiro Hisaki, Takahiro Nakae, Hiroko Yamada, Keishi Ohara, Nagao Kobayashi, Hidemitsu Uno, Chemistry - A European Journal, 20131000, [Refereed], 09476539, 10.1002/chem.201301294
  • Simultaneous control of carriers and localized spins with light in organic materials, Toshio Naito, Tomoaki Karasudani, Keishi Ohara, Takahiro Takano, Yukihiro Takahashi, Tamotsu Inabe, Ko Furukawa, Toshikazu Nakamura, Advanced Materials, 20121200, [Refereed], 09359648, 10.1002/adma.201203153
  • A time-resolved luminescence study on singlet oxygen quenching by hydroxycinnamic acids under acidic, neutral and basic conditions, Keishi Ohara, Kohji Doi, Yuka Niizaki, Shin-ichi Nagaoka, Journal of Photochemistry and Photobiology A: Chemistry, 20121200, [Refereed], 10106030, 10.1016/j.jphotochem.2012.08.021
  • Dual emitting Langmuir-Blodgett films of cationic iridium complexes and montmorillonite clay for oxygen sensing, Kazuya Morimoto, Takahiro Nakae, Keishi Ohara, Kenji Tamura, Shin Ichi Nagaoka, Hisako Sato, New Journal of Chemistry, 20121200, [Refereed], 11440546, 10.1039/c2nj40351j
  • Molecular photoconductor with simultaneously photocontrollable localized spins, Toshio Naito, Tomoaki Karasudani, Shigeki Mori, Keishi Ohara, Kensuke Konishi, Takahiro Takano, Yukihiro Takahashi, Tamotsu Inabe, Sadafumi Nishihara, Katsuya Inoue, Journal of the American Chemical Society, 20121100, [Refereed], 00027863, 10.1021/ja306260b
  • Erratum: UV protection and singlet-oxygen quenching activity of intramolecularly hydrogen-bonded hydroxyanthraquinone derivatives found in aloe (Journal of Photochemistry and Photobiology A: Chemistry (2011) 225 (106-112)), Shin Ichi Nagaoka, Keishi Ohara, Miki Takei, Mari Nakamura, Mariko Mishima, Umpei Nagashima, Journal of Photochemistry and Photobiology A: Chemistry, 20120700, [Refereed], 10106030, 10.1016/j.jphotochem.2012.06.007
  • Erratum: UV protection and singlet oxygen quenching activity of aloesaponarin I (Journal of Physical Chemistry B (2007) 111 (13116-13123) DOI: 10.1021/jp075224j), Shin Ichi Nagaoka, Akiko Fujii, Megumi Hino, Mai Takemoto, Misaki Yasuda, Mariko Mishima, Keishi Ohara, Akane Masumoto, Hidemitsu Uno, Umpei Nagashima, Journal of Physical Chemistry B, 20120200, [Refereed], 15206106, 10.1021/jp300771q
  • UV protection and singlet-oxygen quenching activity of intramolecularly hydrogen-bonded hydroxyanthraquinone derivatives found in aloe, Shin Ichi Nagaoka, Keishi Ohara, Miki Takei, Mari Nakamura, Mariko Mishima, Umpei Nagashima, Journal of Photochemistry and Photobiology A: Chemistry, 20111200, [Refereed], 10106030, 10.1016/j.jphotochem.2011.10.006
  • Cyclo[8]isoindoles: Ring-expanded and annelated porphyrinoids, Tetsuo Okujima, Guangnan Jin, Naoki Matsumoto, John MacK, Shigeki Mori, Keishi Ohara, Daiki Kuzuhara, Chie Ando, Noboru Ono, Hiroko Yamada, Hidemitsu Uno, Nagao Kobayashi, Angewandte Chemie - International Edition, 20110600, [Refereed], 14337851, 10.1002/anie.201007510
  • A photolysis study on superoxide quenching at water/oil interface of Aerosol OT reversed micelle, Keishi Ohara, Akihiro Ikeda, Shin Ichi Nagaoka, Journal of Photochemistry and Photobiology A: Chemistry, 20110200, [Refereed], 1010-6030, 10.1016/j.jphotochem.2010.12.008
  • Hybridization of clay minerals with the floating film of a cationic Ir(iii) complex at an air-water interface, Hisako Sato, Kenji Tamura, Keishi Ohara, Shin Ichi Nagaoka, Akihiko Yamagishi, New Journal of Chemistry, 20110200, [Refereed], 1144-0546, 10.1039/c0nj00534g
  • Synthesis, crystal structure, and photodynamics of π-Expanded Porphyrin-Fullerene dyads synthesized by Diels-Alder reaction, Hiroko Yamada, Kei Ohkubo, Daiki Kuzuhara, Tetsuro Takahashi, Atula S D Sandanayaka, Tetsuo Okujima, Keishi Ohara, Osamu Ito, Hidemitsu Uno, Noboru Ono, Shunichi Fukuzumi, Journal of Physical Chemistry B, 20101200, [Refereed], 1520-6106, 10.1021/jp102966x
  • Vitamin K analogue as a new fluorescence probe for quantitative antioxidant assay, Keishi Ohara, Ryotaro Mitsumori, Mitsuharu Takebe, Daiki Kuzuhara, Hiroko Yamada, Shin Ichi Nagaoka, Journal of Photochemistry and Photobiology A: Chemistry, 20100900, [Refereed], 1010-6030, 10.1016/j.jphotochem.2010.07.020
  • Singlet oxygen lifetime in vitamin E emulsion depends on the oil-droplet size, Keishi Ohara, Takashi Origuchi, Shin Ichi Nagaoka, Bulletin of the Chemical Society of Japan, 20100300, [Refereed], 0009-2673|1348-0634, 10.1246/bcsj.20090277
  • Photochemical formation and decay of tocopheroxyl radical in vitamin E emulsion: A laser-photolysis study, Keishi Ohara, Ayumi Shimizu, Yuki Wada, Shin ichi Nagaoka, Journal of Photochemistry and Photobiology A: Chemistry, 20100200, [Refereed], 1010-6030, 10.1016/j.jphotochem.2010.01.001
  • Singlet oxygen quenching by trolox C in aqueous micelle solutions, Keishi Ohara, Kaori Kikuchi, Takashi Origuchi, Shin ichi Nagaoka, Journal of Photochemistry and Photobiology B: Biology, 20091200, [Refereed], 10111344, 10.1016/j.jphotobiol.2009.08.010
  • Kinetic study of singlet-oxygen quenching by caffeic acid and related phenols, Keishi Ohara, Yoko Ichimura, Shin-ichi Nagaoka, Bulletin of the Chemical Society of Japan, 20090700, [Refereed], 0009-2673|1348-0634, 10.1246/bcsj.82.689
  • New radical salts based on TEMPO-substituted 2,4,6-triphenylpyridinium and transition metal complexes, Bilkish Rahman, Hiroki Akutsu, Jun-ichi Yamada, Keishi Ohara, Shin-ichi Nakatsuji, Synthetic Metals, 20090600, [Refereed], 03796779, 10.1016/j.synthmet.2009.01.046
  • Formation and decay dynamics of vitamin e radical in the antioxidant reaction of vitamin E, Kazuo Mukai, Aya Ouehi, Akiko Mitarai, Keishi Ohara, Chihiro Matsuoka, Bulletin of the Chemical Society of Japan, 20090400, [Refereed], 00092673, 10.1246/bcsj.82.494
  • Tunneling effect in antioxidant reaction of flavonoid, Takuhiro Kakiuchi, Kazuo Mukai, Keishi Ohara, Shin-ichi Nagaoka, Bulletin of the Chemical Society of Japan, 20090300, [Refereed], 0009-2673|1348-0634, 10.1246/bcsj.82.216
  • Time-resolved EPR investigation on the photoreactions of vitamin K with antioxidant vitamins in micelle systems, Keishi Ohara, Yoshimi Hashimoto, Chiaki Hamada, Shin ichi Nagaoka, Journal of Photochemistry and Photobiology A: Chemistry, 20081200, [Refereed], 1010-6030, 10.1016/j.jphotochem.2008.07.011
  • Comparison between the free-radical-scavenging activities with vitamin e and ubiquinol in biological systems based on their reaction rates: A research account, Kazuo Mukai, Aiko Tokunaga, Shingo Itoh, Yu Kanesaki, Aya Ouchi, Keishi Ohara, Shin Ichi Nagaoka, Kouichi Abe, BioFactors, 20081200, [Refereed], 09516433
  • Behavior of singlet oxygen in vitamin E emulsion, Keishi Ohara, Takashi Origuchi, Kanako Kawanishi, Shin-ichi Nagaoka, Bulletin of the Chemical Society of Japan, 20081200, [Refereed], 0009-2673|1348-0634, 10.1246/bcsj.81.345
  • UV protection and singlet oxygen quenching activity of aloesaponarin I, Shin Ichi Nagaoka, Shin Ichi Nagaoka, Akiko Fujii, Megumi Hino, Mai Takemoto, Misaki Yasuda, Mariko Mishima, Keishi Ohara, Keishi Ohara, Akane Masumoto, Hidemitsu Uno, Umpei Nagashima, Journal of Physical Chemistry B, 20071100, [Refereed], 1520-6106, 10.1021/jp075224j
  • Kinetics of the reaction by which natural vitamin E is regenerated by vitamin C, Shin ichi Nagaoka, Takuhiro Kakiuchi, Keishi Ohara, Kazuo Mukai, Chemistry and Physics of Lipids, 20070300, [Refereed], 00093084, 10.1016/j.chemphyslip.2006.12.001
  • Structure-activity relationship of the free-radical-scavenging reaction by vitamin e (α-, β-, γ-, δ-tocopherols) and ubiquinol-10: PH dependence of the reaction rates, Kazuo Mukai, Aiko Tokunaga, Shingo Itoh, Yu Kanesaki, Keishi Ohara, Shin Ichi Nagaoka, Kouichi Abe, Journal of Physical Chemistry B, 20070100, [Refereed], 1520-6106, 10.1021/jp0650580
  • Kinetic study on the free radical-scavenging and vitamin E-regenerating actions of caffeic acid and its related compounds, Keishi Ohara, Yoko Ichimura, Kumi Tsukamoto, Mayumi Ogata, Shin Ichi Nagaoka, Kazuo Mukai, Bulletin of the Chemical Society of Japan, 20061100, [Refereed], 0009-2673|1348-0634, 10.1246/bcsj.79.1501
  • Kinetic study of radical-scavenging and vitamin E-regenerating actions of edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one), Keishi Ohara, Akiko Fujii, Yoko Ichimura, Kazue Sato, Kazuo Mukai, Bulletin of the Chemical Society of Japan, 20061100, [Refereed], 0009-2673|1348-0634, 10.1246/bcsj.79.421
  • An FT-EPR investigation of the anomalous CIDEP in photoreactions of chromone and chromone-2-carboxylic acid with alcohol induced by hydrochloric acid, Keishi Ohara, Debora M. Martino, Hans van Willigen, Journal of Photochemistry and Photobiology A: Chemistry, 20060700, [Refereed], 1010-6030, 10.1016/j.jphotochem.2005.12.014
  • Paramagnetic semiconductors: Hybrid molecular materials based on ethyl- and methyl-pyridinium-substituted verdazyl radical cations and the Ni(dmit) 2 anion (dmit = 1,3-dithiol-2-thione-4,5-dithiolate), Kazuo Mukai, Daisuke Shiba, Kenji Yoshida, Kyohei Mukai, Hiroyuki Hisatou, Keishi Ohara, Yuko Hosokoshi, Nagao Azuma, Bulletin of the Chemical Society of Japan, 20051200, [Refereed], 00092673, 10.1246/bcsj.78.2114
  • Magnetic semiconductors: Molecular materials based on alkyl-pyridinium- substituted verdazyl radical cations and Ni(dmit)2 anion, Kazuo Mukai, Daisuke Shiba, Kyohei Mukai, Kenji Yoshida, Hiroyuki Hisatou, Keishi Ohara, Yuko Hosokoshi, Nagao Azuma, Polyhedron, 20051100, [Refereed], 02775387, 10.1016/j.poly.2005.03.073
  • Photochemical synthesis of pentacene and its derivatives, Hiroko Yamada, Yuko Yamashita, Makoto Kikuchi, Hikaru Watanabe, Tetsuo Okujima, Hidemitsu Uno, Hidemitsu Uno, Takuji Ogawa, Keishi Ohara, Noboru Ono, Chemistry - A European Journal, 20051000, [Refereed], 09476539, 10.1002/chem.200500564
  • Kinetic study of the quenching reaction of singlet oxygen by tea catechins in ethanol solution, Kazuo Mukai, Souichi Nagai, Keishi Ohara, Free Radical Biology and Medicine, 20050900, [Refereed], 08915849, 10.1016/j.freeradbiomed.2005.04.027
  • Structure-activity relationship of the tocopherol-regeneration reaction by catechins, Kazuo Mukai, Shuji Mitani, Keishi Ohara, Shin Ichi Nagaoka, Free Radical Biology and Medicine, 20050500, [Refereed], 08915849, 10.1016/j.freeradbiomed.2005.01.011
  • Kinetic study of the mechanism of free-radical scavenging action in curcumin: Effects of solvent and pH, Keishi Ohara, Wataru Mizukami, Aiko Tokunaga, Shin Ichi Nagaoka, Hidemitsu Uno, Kazuo Mukai, Bulletin of the Chemical Society of Japan, 20050400, [Refereed], 00092673, 10.1246/bcsj.78.615
  • Kinetic study of the quenching reaction of singlet oxygen by flavonoids in ethanol solution, Souichi Nagai, Keishi Ohara, Kazuo Mukai, Journal of Physical Chemistry B, 20050300, [Refereed], 15206106, 10.1021/jp0451389
  • Molecular Paramagnetic Semiconductor: Crystal Structures and Magnetic and Conducting Properties of the Ni(dmit)2 Salts of 6-Oxoverdazyl Radical Cations (dmit = 1,3-Dithiol-2-thione-4,5-dithiolate), K. Mukai, N. Senba, T. Hatanaka, H. Minakuchi, K. Ohara, M. Taniguchi, Y. Misaki, Y. Hosokoshi, K. Inoue, N. Azuma, Inorganic Chemistry, 20040100, [Refereed], 00201669, 10.1021/ic030068q
  • Excited High-Spin Quartet (S = 3/2) State of a Novel π-Conjugated Organic Spin System, Pyrene-Verdazyl Radical, Yoshio Teki, Mituhiro Kimura, Shinsuke Narimatsu, Keishi Ohara, Kazuo Mukai, Bulletin of the Chemical Society of Japan, 20040100, [Refereed], 00092673, 10.1246/bcsj.77.95
  • Time-resolved electron paramagnetic resonance investigation of photoinitiated antioxidant reaction of vitamin C (Ascorbic Acid) with Xanthone in aqueous sodium lauryl sulfate, hexadecyltrimethylammonium chloride, and triton X-100 micelle solutions, Keishi Ohara, Ryo Watanabe, Yoko Mizuta, Shin Ichi Nagaoka, Kazuo Mukai, Journal of Physical Chemistry B, 20031000, [Refereed], 15206106, 10.1021/jp0353486
  • Syntheses and magnetic property of the salts of positively-charged verdazyl radicals and TCNQF 4 - anion radical, Nagao Azuma, Nobuyoshi Senba, Kazuki Okuda, Keishi Ohara, Yuko Hosokoshi, Katsuya Inoue, Kazuo Mukai, Molecular Crystals and Liquid Crystals Science and Technology Section A: Molecular Crystals and Liquid Crystals, 20021200, [Refereed], 1058725X, 10.1080/10587250210771
  • Time-resolved EPR investigation of the photo-initiated intramolecular antioxidant reaction of vitamin K - vitamin E linked molecule, Yoshinori Nishioku, Yoshinori Nishioku, Keishi Ohara, Kazuo Mukai, Shin ichi Nagaoka, Journal of Physical Chemistry B, 20020500, [Refereed], 10895647, 10.1021/jp004375i
  • Anomalous spin polarization in the photoreduction of chromone-2-carboxylic acid with alcohol induced by hydrochloric acid, Keishi Ohara, Kazuo Mukai, Chemical Physics Letters, 20000200, [Refereed], 00092614, 10.1016/S0009-2614(99)01417-7
  • Tunneling Effect in Antioxidant, Prooxidant, and Regeneration Reactions of Vitamin E, Shin Ichi Nagaoka, Masayo Inoue, Chiho Nishioka, Yoshinori Nishioku, Sayuri Tsunoda, Chikage Ohguchi, Keishi Ohara, Kazuo Mukai, Umpei Nagashima, Journal of Physical Chemistry B, 20000200, [Refereed], 1089-5647, 10.1021/jp9932113
  • A CIDEP study on the photosensitized reaction of maleimide with xanthone: Addition effect of hydrochloric acid, Keishi Ohara, Shin-ichi Nagaoka, Kazuo Mukai, Bulletin of the Chemical Society of Japan, Bulletin of the Chemical Society of Japan, 20000100, [Refereed], 00092673, 10.1246/bcsj.73.37
  • Magnetic property of verdazyl radical alloy, (p-CDpOV)<1-x>(p-BDpOV)x. Doping effect of magnetic impurities on quasi-one dimensional Heisenberg organic ferromagnet (p-CDpOV) and antiferromagnet (p-BDpOV) with S = 1/2, Kazuo Mukai, Kentaro Suzuki, Keishi Ohara, Javad B. Jamali, Norio Achiwa, Journal of the Physical Society of Japan, Journal of the Physical Society of Japan, 19990900, [Refereed], 00319015, 10.1143/JPSJ.68.3078
  • An FT-EPR investigation of the anomalous CIDEP observed in photoinduced reactions of xanthone with alcohols in the presence of hydrochloric acid, Keishi Ohara, Keishi Ohara, Noboru Hirota, Debora M. Martino, Debora M. Martino, Hans Van Willigen, Journal of Physical Chemistry A, 19980700, [Refereed], 10895639, 10.1021/jp973380s
  • Anomalous triplet mechanism spin polarization induced by the addition of hydrochloric acid in the photochemical system of xanthone in alcohol, Takehiko Koga, Keishi Ohara, Keishi Ohara, Keiji Kuwata, Hisao Murai, Journal of Physical Chemistry A, 19971000, [Refereed], 10895639, 10.1021/jp971183n
  • CIDEP studies in low-frequency microwave regions. Magnetic field dependence of the CIDEP of spin-correlated radical pairs, Keishi Ohara, Yuji Miura, Masahide Terazima, Noboru Hirota, Journal of Physical Chemistry A, 19970100, [Refereed], 10895639, 10.1021/jp9619752
  • An Analysis of the CIDEP Mechanisms in the Hydrogen Abstraction Reactions of Excited Quinoxaline and Related Compounds, Keishi Ohara, Noboru Hirota, Bulletin of the Chemical Society of Japan, 19960600, [Refereed], 00092673, 10.1246/bcsj.69.1517
  • CW and FT time-resolved EPR investigation of the quenching reaction of the 2-hydroxypropan-2-yl radical, Keishi Ohara, Noboru Hirota, Carlos A. Steren, Hans Van Willigen, Journal of Physical Chemistry, 19960200, [Refereed], 00223654, 10.1021/jp9527362
  • CIDEP studies in low-frequency microwave regions. Magnetic field dependence of the triplet mechanism, Keishi Ohara, Masahide Terazima, Noboru Hirota, Journal of Physical Chemistry, 19951200, [Refereed], 00223654, 10.1021/j100051a003
  • FT-EPR study of the CIDEP of 2-propanolyl radical produced by the reaction of acetone with triethylamine, Keishi Ohara, Noboru Hirota, Carlos A. Steren, Hans van Willigen, Chemical Physics Letters, 19950100, [Refereed], 00092614, 10.1016/0009-2614(94)01310-R
  • CIDEP measurement in the L band microwave frequency region. Hyperfine-independent versus hyperfine-dependent mechanisms in the ST_mixing of acetone in 2-propanol, Masahide Terazima, Yuji Miura, Keishi Ohara, Noboru Hirota, Chemical Physics Letters, 19940700, [Refereed], 00092614, 10.1016/0009-2614(94)00541-9
  • Time-Resolved ESR Studies on Photosensitized Reaction of Maleic Anhydride in Alcohols: CIDEP Memory Transfer in Spin-Adduct Formation, Keishi Ohara, Hisao Murai, Keiji Kuwata, Bulletin of the Chemical Society of Japan, 19920600, [Refereed], 10.1246/bcsj.65.1672
  • Submicrosecond Time-Resolved ESR Study on Photodissociation of 2,2'-Azobis(isobutyronitrile), Toru Takemura, Keishi Ohara, Hisao Murai, Keiji Kuwata, Chemistry Letters, 19900900, [Refereed], 10.1246/cl.1990.1635
  • CIDEP Study of the Photoreduction of Aromatic Ketones with Alkoxides in Alcohols, Keishi Ohara, Hisao Murai, Keiji Kuwata, Bulletin of the Chemical Society of Japan, 19890800, [Refereed], 10.1246/bcsj.62.2435

Books etc

  • 20090000
  • Kinetic Study of Vitamin E Regeneration Reaction with Catechins (EC, EGC, ECG, and EGCG) in Homogeneous and Micellar Solution, Kazuo Mukai, Shuji Mitani, Souichi Nagai, Keishi Ohara, Contributor, Proceedings of the 3rd China-Japan International Conference on Vitamins', Guilin, China, 2004, 20040000
  • 20020000
  • 20020000
  • 20000000
  • CIDEP studies of photochemical reactions at different microwave frequencies, ST0M and ST-M., Keishi Ohara, Noboru Hirota, Contributor, Modern Applications of EPR/ESR: From Biophysics to Materials Science, Proceedings of the Asia-Pacific EPR/ESR Symposium, 1st, Kowloon, Hong Kong, Jan. 20-24, 1997, p114-122, Springer-Verlag, Singapore, 19980000

Works

  • 20040000

Misc

  • 42, 2, 28, 30, 20170500, http://ci.nii.ac.jp/naid/40021247062
  • Analyzing the Outcomes of Educational Development in the Faculty of Science by Student Survey, 髙橋 亮治, 小原 敬士, 松浦 真也, 大学教育実践ジャーナル = Journal of faculty and staff development in higher education, 愛媛大学教育・学生支援機構, 大学教育実践ジャーナル = Journal of faculty and staff development in higher education, 15, 141, 146, 20170300, http://ci.nii.ac.jp/naid/120006240399
  • 光照射下の銅(II)ジチオレン錯体塩の磁性・伝導性, 野間博貴, 小原敬士, 山本貴, 内藤俊雄, 日本化学会中国四国支部大会講演要旨集, 2015, 90, 20151107, http://jglobal.jst.go.jp/public/201602240140968766
  • 近赤外発光スポット検出によるゲル中成分の一重項酸素消去活性計測, 小原敬士, 北平有望, 長岡伸一, 日本化学会中国四国支部大会講演要旨集, 2015, 146, 20151107, http://jglobal.jst.go.jp/public/201602249708231512
  • A study of UV care by molecules contained in aloe-UV protection and singlet-oxygen quenching, 長岡伸一, 小原敬士, Fragr J, 43, 6, 67, 72, 20150615, 0288-9803, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201502218618642075
  • A study of UV care by molecules contained in aloe : UV protection and singlet-oxygen quenching, 長岡 伸一, 小原 敬士, Fragrance journal = フレグランスジャーナル, フレグランスジャーナル社, Fragrance journal = フレグランスジャーナル, 43, 6, 67, 72, 20150600, 0288-9803, http://ci.nii.ac.jp/naid/40020512126
  • 光照射によって不対電子の局在性が変わる銅(II)ジチオレン錯体塩の電気・磁気挙動, 野間博貴, 小原敬士, 山本貴, 内藤俊雄, 日本化学会講演予稿集, 95th, 2, 448, 20150311, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201502201331175581
  • 高い光伝導を示すNMQ[Ni(dmit)2]の伝導機構に関する研究, 長山直樹, 小原敬士, 山本貴, 内藤俊雄, 日本化学会講演予稿集, 95th, 2, 448, 20150311, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201502250993243464
  • シクロデキストリンで水溶化した香辛料成分カプサイシンの一重項酸素消去活性, 小原敬士, 平岡奈保子, 長岡伸一, 日本酸化ストレス学会学術集会プログラム・抄録集, 67th, 102, 20140829, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201402268624669635
  • 近赤外発光寿命計測を基盤とする食品・飲料の抗酸化力評価法の開発と応用, 小原敬士, 日本酸化ストレス学会学術集会プログラム・抄録集, 67th, 71, 20140829, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201402290823879881
  • Ni‐dmit錯体の特異的に大きな光伝導性, 内藤俊雄, 烏谷知明, 長山直樹, 小原敬士, 小西健介, 森重樹, 高野崇廣, 高橋幸裕, 稲辺保, 木瀬翔太, 西原禎文, 井上克也, 日本化学会講演予稿集, 94th, 2, 261, 20140312, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201402224610722714
  • 分子内水素結合したアントラキノン類における励起状態分子内プロトン移動と一重項酸素消去活性の相関, 長岡伸一, 遠藤光, 小原敬士, 光化学討論会講演要旨集, 2013, 244, 20130907, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302224703845983
  • イリジウム錯体単分子膜の人工積層法による多重発光特性, 佐藤久子, 森本和也, 小原敬士, 長岡伸一, 田村堅志, 日本化学会講演予稿集, 93rd, 3, 1054, 20130308, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201302235013126951
  • 多環式芳香族縮環シクロ[8]ピロールの合成と物性, 安藤千恵, 松本直樹, 森重樹, 小原敬士, 中江隆博, 宇野英満, 奥島鉄雄, 基礎有機化学討論会要旨集, 23rd, 243, 20120905, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201202209179632920
  • ナフタレン縮環シクロ[8]ピロールの合成と物性, 安藤千恵, 松本直樹, 小原敬士, 森重樹, 中江隆博, 山田容子, 宇野英満, 奥島鉄雄, 日本化学会講演予稿集, 92nd, 4, 1596, 20120309, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201202212078141934
  • イリジウム金属錯体と粘土鉱物のハイブリッドLB膜による多色発光挙動, 中谷康彦, 森本和也, 小原敬士, 長岡伸一, 田村堅志, 佐藤久子, 日本化学会講演予稿集, 92nd, 3, 895, 20120309, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201202221361326192
  • 稀少試料の抗酸化活性評価のための一重項酸素発光寿命のスポット計測, 小原敬士, 日本化学会講演予稿集, 92nd, 2, 673, 20120309, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201202235014977443
  • 光応答性が期待される分子性伝導体の構造と物性, 内藤俊雄, 烏谷知明, 森重樹, 小原敬士, 小西健介, 高野崇廣, 高橋幸裕, 稲辺保, 日本化学会講演予稿集, 92nd, 2, 300, 20120309, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201202285705664759
  • ビタミンEエマルションのフリーラジカル消去活性, 小原敬士, 迫佳志, 長岡伸一, 日本化学会講演予稿集, 92nd, 3, 1102, 20120309, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201202289608294233
  • 様々な抗酸化物質によるアルキルラジカル消去能の速度論的定量化, 石川美紗, 立川由貴, 小原敬士, 古武弥成, 末石芳巳, 電子スピンサイエンス学会年会講演要旨集, 50th, 66, 67, 20111116, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201102214566117991
  • コーヒー酸の塩による高速一重項酸素消去, 小原敬士, 新崎由佳, 長岡伸一, 日本化学会西日本大会講演要旨集, 2011, 213, 20111107, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201202202571620412
  • モンモリロナイトとイリジウム錯体とのハイブリッドLB膜の発光挙動, 中谷康彦, 堤響子, 中江隆博, 小原敬士, 長岡伸一, 森本和也, 田村堅志, 佐藤久子, 粘土科学討論会講演要旨集, 55th, 276, 277, 20110914, 10.11362/cssj2.55.0_276, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201102242674640653
  • 9,10‐アントラセンおよびアセナフチレン縮環シクロ[8]ピロールの合成と物性, 安藤千恵, 松本直樹, 森重樹, 宇野英満, 小原敬士, 中江隆博, 奥島鉄雄, 基礎有機化学討論会要旨集, 22nd, 505, 20110907, 10.11494/kisoyuki.2011.0.374.0, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201102292687695845
  • Synthesis and properties of 9,10-anthracene- and 1,2-acenaphthylene-fused cyclo[8]pyrrole, Ando Chie, Matsumoto Naoki, Mori Shigeki, Uno Hidemitsu, Ohara Keishi, Nakae Takahiro, Okujima Tetsuo, Abstracts of Symposium on Physical Organic Chemistry, The Society of Physical Organic Chemistry, Japan, Abstracts of Symposium on Physical Organic Chemistry, 2011, 374, 374, 20110000, 10.11494/kisoyuki.2011.0.374.0, http://ci.nii.ac.jp/naid/130004645894, In recent years there has been a growing focus on the chemistry of ring-expanded porphyrins such as hexaphyrins and octaphyrins, because their properties differ markedly from those of conventional porphyrins in a manner that makes them potentially suitable for a number of novel practical applications. First cyclo[8]pyrrole ([30]octaphyrin(0.0.0.0.0.0.0.0)) has been reported by Sessler and his co-workers based on an oxidative-coupling of 2,2'-bipyrrole in 2002. Recently, we reported the first successful synthesis of cyclo[8]isoindole based on an oxidative-coupling of bicyclo[2.2.2]octadiene(BCOD)-fused 2,2'-bipyrrole, followed by the retro-Diels-Alder reaction. Herein we report synthesis 9,10-anthracene- and 1,2-acenaphthylene-fused cyclo[8]pyrroles by oxidative-coupling of 2,2'-bipyrrole and their vis-NIR absorptions, fluorescence spectra and molecular structures by X-ray crystal structural analysis.
  • 55, 276, 277, 20110900, 10.11362/cssj2.55.0_276, http://ci.nii.ac.jp/naid/110008756850
  • 24, 84, 87, 20100900
  • ビタミンK誘導体の遅延蛍光を用いた抗酸化活性評価, 小原敬士, 光森亮太朗, 長岡伸一, 日本酸化ストレス学会学術集会プログラム・抄録集, 63rd, 113, 20100624, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201002201350872351
  • 一重項酸素寿命に及ぼす抗酸化剤‐金ナノ粒子の影響, 池田明広, 大倉さとみ, 小原敬士, 長岡伸一, 日本酸化ストレス学会学術集会プログラム・抄録集, 63rd, 111, 20100624, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201002294293801629
  • イリジウム錯体と粘土とのハイブリッドLB膜によるガスセンシング, 佐藤久子, 国吉勇司, 小原敬士, 長岡伸一, 田村堅志, 山岸晧彦, 日本化学会講演予稿集, 90th, 3, 856, 20100312, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201002213495993899
  • ビタミンKの蛍光の消光による抗酸化作用の評価, 光森亮太朗, 小原敬士, 長岡伸一, 日本化学会西日本大会講演要旨集, 2009, 225, 20091107, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201002250188986446
  • ビタミンE光分解系におけるAOT油水界面でのビタミンCによる抗酸化挙動, 池田明広, 小原敬士, 長岡伸一, 日本化学会西日本大会講演要旨集, 2009, 182, 20091107, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=201002276436464868
  • Quantum effect in regeneration reaction of vitamin E, 長岡伸一, 大内綾, 垣内拓大, 小原敬士, 向井和男, ビタミン, 83, 9, 521, 527, 20090925, 0006-386X, 10.20632/vso.83.9_521, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902242555814980
  • Quantum effect in regeneration reaction of vitamin E, Nagaoka Shin-ichi, Ouchi Aya, Kakiuchi Takuhiro, Ohara Keishi, Mukai Kazuo, Vitamins, The Vitamin Society of Japan, Vitamins, 83, 9, 521, 527, 20090900, 0006386X, 10.20632/vso.83.9_521, http://ci.nii.ac.jp/naid/110007387825, Recent studies on the kinetics of the regeneration reactions of vitamin E in solutions by means of stopped-flow spectroscopy confirmed that the quantum effect often plays an important role. Vitamin E may inhibit the autooxidation of lipids in cellular membranes by taking advantage of proton tunneling. It is interesting that the microscopic quantum-mechanical tunneling effect manifests itself in a macroscopic vital function. Although this finding is in conflict with our intuition at first glance, living cells might, in reality, know quantum mechanics very well and use them effectively.
  • UV protection and singlet oxygen quenching activity of aloesaponarin I, Nagaoka Shin-ichi, Fujii Akiko, Hino Megumi, Takemoto Mai, Yasuda Misaki, Mishima Mariko, Ohara Keishi, Masumoto Akane, Uno Hidemitsu, Nagashima Umpei, Vitamins, The Vitamin Society of Japan, Vitamins, 83, 5, 288, 289, 20090600, 0006386X, http://ci.nii.ac.jp/naid/110007338063
  • Antioxidant behavior of vitamin C for photolysis of vitamin E in AOT reversed micelle, 池田明広, 小原敬士, 長岡伸一, 日本化学会講演予稿集, 89th, 1, 592, 20090313, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902259244915847
  • Droplet-size dependence of singlet-oxygen lifetime in vitamin E emulsion, 折口孝, 小原敬士, 長岡伸一, 日本化学会講演予稿集, 89th, 1, 185, 20090313, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902262416347448
  • ビタミンEを含むミセル系における一重項酸素発光寿命, 折口孝, 菊地香織里, 小原敬士, 長岡伸一, 日本化学会講演予稿集, 88th, 1, 491, 20080312, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902206429666880
  • ビタミンEの不均一系での抗酸化反応の速度論的研究, 吉本摩耶, 小原敬士, 長岡伸一, 日本化学会講演予稿集, 88th, 1, 761, 20080312, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902266804314875
  • 不均一系におけるビタミンEの光化学反応の研究, 清水亜由美, 和田有紀, 小原敬士, 長岡伸一, 分子科学討論会講演要旨集(CD-ROM), 1st, 3P100, 20070824, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902222641661435
  • カテキン類によるビタミンE再生作用の速度論的研究, 新田晃子, 長岡伸一, 小原敬士, 向井和男, 分子科学討論会講演要旨集(CD-ROM), 1st, 1P136, 20070824, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902233886897142
  • ビタミンEの抗酸化反応におけるEラジカルの生成・消滅ダイナミクス, 向井和男, 大内綾, 小原敬士, 松岡千博, 日本化学会講演予稿集, 87th, 2, 1174, 20070312, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902291509005709
  • 電子スピン分極と磁場効果―Multifrequency Time‐Resolved EPR―, 小原敬士, 分光研究, 55, 4, 263, 264, 20060815, 0038-7002, 10.5111/bunkou.55.263, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902269266365510
  • Multifrequency Time-Resolved EPR, Keishi Ohara, Journal of the spectroscopical research of Japan, 55, 4, 263, 264, 20060800, 00387002, 10.5111/bunkou.55.263, http://ci.nii.ac.jp/naid/10017533061
  • 16, 12, 14, 20060000
  • ビタミンEの抗酸化反応におけるEラジカルの生成・消滅ダイナミクス, 向井和男, 大内綾, 山本峻之, 御手洗亜紀子, 小原敬士, 松岡千博, 電子スピンサイエンス学会年会講演要旨集, 44th, 168, 169, 20051024, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902237836981938
  • 天然抗酸化剤のフリーラジカル消去活性―時間分解ESRではどのようにみえるか, 小原敬士, 中部化学関係学協会支部連合秋季大会講演予稿集, 36th, 139, 20050923, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902230270817227
  • 蛍光検出法による懸濁液系での天然抗酸化剤のフリーラジカル消去速度測定, 小原敬士, 仲原英記, 長岡伸一, 分子構造総合討論会講演要旨集(CD-ROM), 2005, 2P160, 20050901, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902276658442330
  • A Kinetic Study on the Vitamin E Regeneration Reaction with Catechins, 末光藍, 小原敬士, 長岡伸一, 向井和男, 日本化学会講演予稿集, 85th, 2, 828, 20050311, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902209456096490
  • Pure Organic Magnetic Semiconductor - Syntheses and Physical Properties of (1:1) and (1:2) Me2-TCNQ Salts of Methyl-Pyridinium-Substituted Verdazyl Radical Cations, 高見安代, 向恭平, 吉田顕二, 小原敬士, 向井和男, 日本化学会講演予稿集, 85th, 1, 367, 20050311, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902270606410920
  • Stopped-flow Kinetic Study of Natural Vitamin E Regeneration Reaction with Caffeic Acid Derivatives, 一村陽子, 小原敬士, 向井和男, 日本化学会講演予稿集, 85th, 2, 1455, 20050311, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902298349132711
  • 14, 10, 12, 20050000
  • ビタミンC,E共存下の逆ミセル界面における抗酸化反応の時間分解EPR及び速度論的研究, 中村美幸, 小原敬士, 浜田千晶, 向井和男, 電子スピンサイエンス学会年会講演要旨集, 43rd, 170, 171, 20041110, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902249633663653
  • 分子性磁気伝導体:分子内に正電荷を有する6‐オキソフェルダジルラジカル類の[Ni(dmit)2]塩の構造・磁性・伝導性, 向井和男, 水口斉, 仙波伸得, 小原敬士, 東長雄, 分子構造総合討論会講演要旨集(CD-ROM), 2004, 3A15, 20040901, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902227783945246
  • アルキルピリジニウム置換フェルダジルラジカルのNi(dmit)2塩の構造・磁性・伝導性, 向恭平, 芝大介, 小原敬士, 東長雄, 向井和男, 奥田一樹, 井上克也, 分子構造総合討論会講演要旨集(CD-ROM), 2004, 4P002, 20040901, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902261848370355
  • Flavonoidの抗酸化作用におけるトンネル効果の研究, 垣内拓大, 小原敬士, 長岡伸一, 向井和男, 分子構造総合討論会講演要旨集(CD-ROM), 2004, 3P077, 20040901, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902265114324910
  • Kinetic study of the quenching reaction of singlet oxygen by flavonoids in ethanol solution., 永井荘一, 島居七帆, 小原敬士, 向井和男, 日本化学会講演予稿集, 84th, 2, 994, 20040311, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902228077310609
  • Singlet-Oxygen-Quenching and Radical-Scavenging Activities of Caffeic Acid Derivatives, 一村陽子, 永井荘一, 徳永愛子, 小原敬士, 向井和男, 日本化学会講演予稿集, 84th, 2, 994, 20040311, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902250401875288
  • A Time-resolved EPR Observation on the Antioxidant Reaction of Vitamin C and E versus the excited Vitamin K in AOT Reversed Micelle, 中村美幸, 小原敬士, 浜田千晶, 向井和男, 日本化学会講演予稿集, 84th, 2, 1133, 20040311, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902250993904617
  • Solvent Dependence on Free-Radical Scavenging Activities of Curcumin and its Related Compounds, 水上渉, 小原敬士, 徳永愛子, 向井和男, 宇野英満, 日本化学会講演予稿集, 84th, 2, 1340, 20040311, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902279065765442
  • 時間分解ESR法によるAOT逆ミセル系でのビタミンC,E類とビタミンKモデル分子の抗酸化反応の研究, 小原敬士, 浜田千晶, 向井和男, 電子スピンサイエンス学会年会講演要旨集, 42nd, 357, 358, 20031020, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902268814445148
  • 純有機磁気伝導体:分子内に正電荷を有するフェルダジルラジカル類のTCNQ塩の構造・磁性・伝導性, 向井和男, 陣野俊介, 吉田顕二, 神原貴尚, 小原敬士, 東長雄, 電子スピンサイエンス学会年会講演要旨集, 42nd, 10, 12, 20031020, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902281734019098
  • アルキルピリジニウム置換フェルダジルラジカルのPd(dmit)2塩の磁性と伝導性, 吉田顕二, 神原貴尚, 小原敬士, 東長雄, 向井和男, 奥田一樹, 井上克也, 分子構造総合討論会講演要旨集(CD-ROM), 2003, 1PA127, 20030920, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902203296705195
  • 分子性磁気伝導体:分子内に正の電荷を有するフェルダジルラジカルのM(dmit)2(M=Ni,Pd)塩の構造・磁性・伝導性, 向井和男, 芝大介, 神原貴尚, 吉田顕二, 向恭平, 小原敬士, 東長雄, 分子構造総合討論会講演要旨集(CD-ROM), 2003, 1AP01, 20030920, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902254847766836
  • Tetramethyl‐p‐phenylenediamineカチオンのM(dmit)2塩(M=Ni, Pd, Zn)の磁性と伝導性, 甲祐一朗, 小原敬士, 東長雄, 向井和男, 奥田一樹, 井上克也, 分子構造総合討論会講演要旨集(CD-ROM), 2003, 1PP135, 20030920, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902287475760467
  • 分子内に正電荷を持つ6‐オキソフェルダジルラジカルの[Ni(dmit)2]塩の構造,磁性,及び伝導性, 水口斉, 吉田顕二, 小原敬士, 東長雄, 向井和男, 奥田一樹, 井上克也, 分子構造総合討論会講演要旨集(CD-ROM), 2003, 1PP131, 20030920, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902298880570669
  • Structure-activity relationship in quenching reaction of singlet oxygen by catechins; EC, EGC, ECG, EGCG, 永井荘一, 島居七帆, 小原敬士, 向井和男, 日本化学会講演予稿集, 83rd, 2, 791, 20030303, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902269769074482
  • 時間分解ESRを用いた天然抗酸化剤の光誘起抗酸化反応及び一重項酸素消去活性の研究, 小原敬士, 日本化学会西日本大会講演予稿集, 2002, 249, 250, 20021102, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902142755275035
  • 時間分解ESR法によるAOT逆ミセル系でのビタミンCとビタミンKモデル分子の光誘起抗酸化反応の研究, 小原敬士, 浜田千晶, 武部光晴, 向井和男, ESR討論会講演要旨集, 41st, 208, 209, 20021017, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902127013153673
  • 高周波ESRの装置の現状と応用展開 分子性磁気半導体 分子内に正電荷を有する6‐オキソフェルダジルラジカル類の[Ni(dmit)2]-塩の構造・磁性・伝導性, 向井和男, 仙波伸得, 畑中貴志, 小原敬士, 東長雄, 谷口正輝, 御崎洋二, 細越裕子, 井上克也, ESR討論会講演要旨集, 41st, 164, 166, 20021017, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902133098960661
  • アルキルピリジニウム置換フェルダジルラジカルのMe2‐TCNQ塩の磁性と伝導性, 神原貴尚, 陣野俊介, 小原敬士, 東長雄, 向井和男, 細越裕子, 井上克也, 分子構造総合討論会講演要旨集, 2002, 617, 20021001, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902116069506151
  • 競争反応法及び時間分解ESR法によるフラボン及びカテキン類の一重項酸素消去速度の測定, 永井荘一, 鳥居七帆, 小原敬士, 向井和男, 分子構造総合討論会講演要旨集, 2002, 267, 20021001, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902152633050038
  • Pure Organic Magnetic Semiconductor-Syntheses and Physical Properties of (1:1) and (1:2) TCNQ Salts of Chloro-Substituted Verdazyl Radical Cations., 吉田顕二, 小原敬士, 東長雄, 向井和男, 細越裕子, 井上克也, 日本化学会講演予稿集, 81st, 1, 340, 20020311, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902115562522640
  • Syntheses and Physical Properties of the Complexes of Methyl-Pyridinium-Substituted 6-Oxo- and 6-Thioxo-Verdazyl Radicals with TCNQ and Its Related Compounds., 奥田一樹, 陣野俊介, 小原敬士, 東長雄, 向井和男, 細越裕子, 井上克也, 日本化学会講演予稿集, 81st, 1, 346, 20020311, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902131816626349
  • Time-resolved ESR study of quenching rate of singlet oxygen by flavones., 永井荘一, 島居七帆, 小原敬士, 向井和男, 日本化学会講演予稿集, 81st, 1, 290, 20020311, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902174385941633
  • Synthesis and Magnetic Property of 6-Oxo- and -Thioxo- Verdazyl Radicals With a Negatively-Charged Site., 成松信輔, 小原敬士, 向井和男, 細越裕子, 井上克也, 構造有機化学討論会講演予稿集, 31st, 321, 20011027, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902106548376429
  • 純有機磁気伝導体の合成と性質 クロロ置換フェルダジルラジカルカチオンのTCNQ塩, 吉田顕二, 小原敬士, 東長雄, 向井和男, 細越裕子, 井上克也, 日本化学会中国四国・同九州支部合同大会講演要旨集, 2001, 184, 20011027, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902119449599879
  • クルクミン類の抗酸化反応のメカニズム, 水上渉, 徳永愛子, 小原敬士, 長岡伸一, 向井和男, 宇野英満, 日本化学会中国四国・同九州支部合同大会講演要旨集, 2001, 40, 20011027, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902143873215370
  • 茶カテキン類とその関連化合物によるフリーラジカル消去作用の速度論的研究, 三谷修二, 小原敬士, 長岡伸一, 向井和男, 日本化学会中国四国・同九州支部合同大会講演要旨集, 2001, 43, 20011027, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902149608228409
  • Study on dynamics of singlet oxygen in micelle system by CIDEP radical probe method., 後藤英夫, 大谷茂利, 小原敬士, 向井和男, 日本化学会講演予稿集, 79th, 1, 150, 20010315, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902139888068899
  • Time Resolved ESR Investigation of Antioxidant Reaction of Vitamin C with Excited Xanthone in Micellar Systems., 渡辺亮, 小原敬士, 水田陽子, 向井和男, 日本化学会講演予稿集, 79th, 1, 151, 20010315, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902152286132568
  • 16, 10, 15, 20010000
  • Time-resolved ESR study of the photo-excited high-spin state of a .PI.-Conjugated Spin Systems constructed from a condensed polyaromatics and a verdazyl radical. Photo-Induced Spin Alignment in Organic Magnetic Materials Utilizing the Excited Molecular Fi, 木村光博, 手木芳男, 成松信輔, 小原敬士, 向井和男, ESR討論会講演要旨集, 39th, 101, 103, 20001103, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902140582339374
  • 縮合多環芳香族と安定フェルダジルラジカルからなるπ共役スピン系の合成,磁性と光励起高スピン状態, 成松信輔, 小原敬士, 向井和男, 手木芳男, 木村光博, 日本化学会中国四国・同九州支部合同大会講演要旨集, 2000, 123, 20001028, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902151566565226
  • Photo-Excited High-Spin States of Condensed Polyaromatics-Verdazyl Radicals on .PI.-Conjugated Spin Systems-Photo-Induced Spin Alignment in Organic Magnetic Materials Utilizing the Excited Molecular Field., 手木芳男, 木村光博, 成松信輔, 小原敬士, 向井和男, 分子構造総合討論会講演要旨集, 2000, 531, 20000927, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902194025316925
  • Fluorescence Investigation on the Interaction between the Excited State of Vitamin K Model Compounds and Vitamin E., 武部光晴, 西奥義憲, 小原敬士, 長岡伸一, 向井和男, 光化学討論会講演要旨集, 2000, 305, 20000910, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902196218697546
  • Crystal structure and molecular magnetism of TCNQF4 complexes of 6-oxoverdazyl cation radical derivatives., 仙波伸得, 東長雄, 小原敬士, 向井和男, 細越裕子, 井上克也, 日本化学会講演予稿集, 78th, 2, 1219, 20000315, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902193259063315
  • Transient grating method for optical heterodyne detection and its applications., 小原敬士, 光化学, 30, 3, 258, 259, 19991225, 0913-4689, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902100791864280
  • 30, 3, 258, 259, 19991200, 09134689, http://ci.nii.ac.jp/naid/10010573973
  • Mechanism of Antioxidant Reaction of Vitamin C in Micellar System as Studied by Time Resolved ESR Method., 渡辺亮, 水田陽子, 小原敬士, 向井和男, ESR討論会講演要旨集, 38th, 98, 99, 19991110, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902184039123822
  • An Investigation on the Intramolecular Photoinduced Oxidation-Antioxidation Reaction of the Vitamin E-Naphthoquinone Linked Molecule., 西奥義憲, 小原敬士, 長岡伸一, 向井和男, 分子構造総合討論会講演要旨集, 1999, 119, 19990927, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902131303856756
  • Spin-Correlated Radical Pair Observed on the Photolysis of Vitamin K with Vitamin C in AOT Reversed Micelle., 橋本芳美, 小原敬士, 向井和男, 光化学討論会講演要旨集, 1999, 65, 19990909, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902181963012604
  • Mechanism of Antioxidant Reaction of Vitamin C in Micellar System as Studied by Time Resolved ESR Method., 渡辺亮, 水田陽子, 小原敬士, 向井和男, 日本化学会講演予稿集, 76th, 2, 767, 19990315, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902107311550064
  • pH Dependence of Aroxyl Radical Scavenging Activity of Vitamin E Derivatives in Micellar Solution., 徳永愛子, 兼崎友, 小原敬士, 長岡伸一, 向井和男, 日本化学会講演予稿集, 76th, 2, 767, 19990315, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902184084809247
  • 生体中のビタミンEの抗酸化反応におけるトンネル効果の研究 (文部省S), 長岡伸一, 西奥義憲, 小原敬士, 向井和男, 多自由度系としての原子集団及び原子のトンネル現象 平成8年度 第4回研究会(賢島)特集号 平成11年, 42, 46, 19990000, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902183325455194
  • Effect of addition of hydrochloric acid on CIDEP observed in photosensitizing reaction of maleimide., 小原敬士, 向井和男, ESR討論会講演要旨集, 37th, 9, 10, 19981000, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902167782595338
  • Research on photochemical reaction of vitamin E - naphthoquinone cross-link molecule using time resolution ESR., 西奥義憲, 小原敬士, 長岡伸一, 向井和男, ESR討論会講演要旨集, 37th, 100, 101, 19981000, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902182863302296
  • An FT-EPR Investigation of the Anomalous CIDEP observed in the Photoinduced Reactions of Chromone and Related Compounds with Alcohols in the presence of Hydrochloric Acid., 小原敬士, MARTINO D M, VAN WILLIGEN H, 光化学討論会講演要旨集, 1998, 10, 19980900, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902115196581417
  • パラ‐ジメチルアミノ置換フェルダジルラジカルとそのヨウ化アルキル錯体の分子磁性, 仙波伸得, 小原敬士, 長岡伸一, 向井和男, 植田一正, 杉本豊成, 分子構造総合討論会講演要旨集, 1998, 632, 19980900, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902179264875082
  • The Effect of addition of hydrochloric acid on CIDEP observed on the photoreduction of chromone-2-carboxylic acid in alcohols., 小原敬士, 向井和男, 日本化学会講演予稿集, 74th, 1, 410, 19980300, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902106114640926
  • Time-Resolved ESR Study of Photo-Redox Reactions between Flavonoids and Vitamins., 橋本芳美, 小原敬士, 向井和男, 日本化学会講演予稿集, 74th, 1, 400, 19980300, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902182186529220
  • Stoructural science and various functions in hydorogen-bond materials. Tunneling Effect in Regeneration Reactions of Vitamin E., 長岡伸一, 西奥義憲, 小原敬士, 向井和男, 日本結晶学会誌, 40, 1, 119, 123, 19980200, 0369-4585, 10.5940/jcrsj.40.119, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902155329258551
  • Tunneling Effect in Regeneration Reactions of Vitamin E, NAGAOKA Shin-ichi, NISHIOKU Yoshinori, OHARA Keishi, MUKAI Kazuo, X-RAYS, The Crystallographic Society of Japan, 日本結晶学会誌, 40, 1, 119-123,133-133, 123, 19980200, 03694585, 10.5940/jcrsj.40.119, http://ci.nii.ac.jp/naid/10002590483, Since a vitamin E radical produced by the antioxidant reaction of vitamin E causes damage to vital functions, ubiquinol and vitamin C regenerate a vitamin E molecule from a vitamin E radical in vivo. The kinetic studies of the regeneration reactions have been carried out in solutions by means of stopped-flow spectroscopy. Substantial deuterium kinetic-isotope-effects on the second-order rate constants have been observed in both the reactions of ubiquinol and vitamin C. Furthermore, a deviation from a linear relationship in the Arrhenius plot has been observed in the reaction of ubiquinol. These results suggest that the tunneling effect plays an important role in the regeneration reactions in various tissues and mitochondria.
  • Research on tunnel effect in antioxidant reaction of vitamin E in vivo. (Ministry of Education S), 長岡伸一, 西奥義憲, 小原敬士, 向井和男, 多自由度系としての原子集団及び原子のトンネル現象 平成8年度 平成10年2月, 33, 37, 19980000, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902124939002939
  • Magnetism of the radical alloy(p-CDpOV)1-x(p-BDpOV)x of the organic ferromagnet p-CDpOV and the one-dimensional antiferromagnet p-BDpOV., 鈴木健太郎, 小原敬士, 向井和男, JAMALI J B, 阿知波紀郎, 分子構造総合討論会講演要旨集, 1997, 737, 19971000, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902135959226541
  • キサントン類の光還元反応のCIDEPに対する塩酸添加の効果, 小原敬士, ESR討論会講演要旨集, 36th, 59, 60, 19971000, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902137410940695
  • The Effect with Addition of Hydrochloric Acid to the CIDEP on the Photoreduction of Xanthone in Alcohols., 小原敬士, 広田のぼる, MARTINO D M, WILLIGEN H V, 光化学討論会講演要旨集, 1997, 55, 19970800, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902170676869292
  • FT-EPR Investigation of CIDEP on Photoreduction of Xanthone in Alcohols with Hydrochloric Acid., 小原敬士, 広田のぼる, MARTINO D M, VAN WILLIGEN H, 日本化学会講演予稿集, 72nd, 1, 212, 19970300, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902154643295198
  • Magnetic Behavior of Mixed Crystal of 1,3,5-Triphenyl-6-oxoverdazyl and Its Nonmagnetic Reduced Form., 鈴木健太郎, 小原敬士, 向井和男, JAMALI J B, 阿知波紀郎, 松田建児, 岩村秀, 日本化学会講演予稿集, 72nd, 1, 269, 19970300, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902158877046731
  • Plasma melting processing equipment of miscellaneous solid waste., 辻行人, 小原敬士, 土屋明夫, 中山嘉久, 原子力工業, 43, 2, 75, 79, 19970200, 0433-4035, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902111664119313
  • The CIDEP Studies in Low-Frequency Microwave Regions. Magnetic Field Dependence of the Spin-Correlated Radical Pairs of Alkyl-chain Linked Biradicals., 小原敬士, 寺嶋正秀, 広田のぼる, 谷本能文, ESR討論会講演要旨集, 35th, 173, 174, 19961000, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902128961825090
  • ESR study on the changes of g-value and line-width in radical alloys of oxoverdazyl radicals., 怒和正明, 鈴木健太郎, 武田英樹, 小原敬士, 東長雄, 向井和男, ESR討論会講演要旨集, 35th, 119, 120, 19961000, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902153570326417
  • The anomalous magnetic behavior of 1,5-diphenyl-3(3- and 4-pyridyl)verdazyl radical at low temperaure., 松原光秀, 小原敬士, 向井和男, JAMALI J B, 阿知波紀郎, 分子構造総合討論会講演要旨集, 1996, 309, 19961000, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902159617617910
  • Magnetism of the molecular alloy of weak ferromagnet, 1,3,5-triphenyl-6-oxoverdazyl radical, and its nonmagnetic reduced form., 鈴木健太郎, 小原敬士, 向井和男, JAMALI J B, 阿知波紀郎, 分子構造総合討論会講演要旨集, 1996, 308, 19961000, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902195985218924
  • 11, 13, 18, 19960000
  • The Investigation of CIDEP Mechanisms in the Low Microwave Frequency Regions. External Magnetic Field Effect of the Spin-Correlated Radical Pair CIDEP., 小原敬士, 三浦裕司, 寺嶋正秀, 広田のぼる, ESR討論会講演要旨集, 34th, 178, 180, 19951000, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902125713724733
  • The Investigation of CIDEP Mechanisms in the Low Microwave Frequency Regions. External Magnetic Field Dependence of the Triplet Mechanism., 小原敬士, 寺嶋正秀, 広田のぼる, ESR討論会講演要旨集, 34th, 181, 183, 19951000, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902160336493888
  • An Analysis of the CIDEP Mechanism on the Hydrogen Abstraction Reaction of Quinoxaline and the Related Compounds., 小原敬士, 広田のぼる, 分子構造総合討論会講演要旨集, 1995, 19, 19950900, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902176054914710
  • FT及びCW時間分解ESRによるピラジニルラジカルの二次的生成反応の研究, 小原敬士, 広田のぼる, STEREN C, VAN WILLIGEN H, 光化学討論会講演要旨集, 1994, 429, 430, 19941000, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902190138194804
  • The Investigation of CIDEP Mechanisms in the Low Microwave Frequency Regions. Magnetic Field Effect of the Spin Polarization of the Triplet Mechanism., 小原敬士, 三浦裕司, 寺嶋正秀, 広田のぼる, ESR討論会講演要旨集, 33rd, 3, 5, 19940900, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902105768297248
  • CIDEP measurement of acetone in the low microwave frequency., 三浦裕司, 小原敬士, 寺嶋正秀, 広田のぼる, ESR討論会講演要旨集, 33rd, 84, 85, 19940900, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902188525969909
  • CIDEP Study of the Photoreduction of Acetone with Amines. An FT-EPR Investigation., 小原敬士, 広田のぼる, STEREN C, VAN WILLIGEN H, 日本化学会講演予稿集, 67th, 1, 140, 19940300, 0285-7626, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902122494332493
  • 低周波時間分解ESR法によるスピン分極の生成・消失機構の検討 (1), 三浦裕司, 小原敬士, 寺嶋正秀, 広田のぼる, ESR討論会講演要旨集, 32nd, 143, 145, 19931000, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902150419355783
  • 低周波時間分解ESR法によるスピン分極の生成・消失機構の検討 (2) 三重項機構の寄与について, 小原敬士, 三浦裕司, 寺嶋正秀, 広田のぼる, ESR討論会講演要旨集, 32nd, 112, 113, 19931000, http://jglobal.jst.go.jp/detail.php?from=API&JGLOBAL_ID=200902188150310840

Other Research Activities

Research Grants & Projects

  • Japan Society for the Promotion of Science (JSPS), Grants-in-Aid for Scientific Research (Scientific Research (C)), Keishi OHARA
  • Ministry of Education, Culture, Sports, Science and Technology, Grants-in-Aid for Scientific Research(基盤研究(C)), Antioxidant activity evaluation of trace sample by the spot measurement of singlet oxygen luminescence lifetime, Keishi OHARA, 物理系薬学, 基盤研究(C), 愛媛大学, In order to evaluate antioxidant activities of trace amount of natural materials, a method of measuring lifetimes of singlet oxygen near-infrared luminescence using a fiber-spot probe (0.4 mm) was developed. Time-evolutions of singlet oxygen luminescence were successfully obtained from measurements of less than 0.1 mL of solutions and also hydrogel samples by the spot method. The quenching rate constants for trace amount of samples such as 0.05 mg of carotenoid isomers, and also that of the quencher in hydro-gel samples were determined. The relationship between singlet oxygen quenching activity and chemical structure for the lipophilic constituents of spices such as capsaicin were investigated in the cyclodextrin aqueous solution. However, in the spot measurements, the photo-damages often occurred in test materials and/or photosensitizers in the accumulation time (10 min). The shorter accumulation time (< 1 min) is hopeful for applying the spot-scan method to the antioxidant assay.
  • Ministry of Education, Culture, Sports, Science and Technology, Grants-in-Aid for Scientific Research(基盤研究(C)), Kinetics and Spin-Dynamics in Quenching Reactive Oxygen Species with Natural Antioxidants in Dispersion / Emulsion Systems, Keishi OHARA, 物理化学, 基盤研究(C), 愛媛大学
  • Ministry of Education, Culture, Sports, Science and Technology, Grants-in-Aid for Scientific Research(基盤研究(C)), Development of Superconducting Ferromagnet Based on New Verdazyl Radical Complex, Kazuo MUKAI, Keishi OHARA, 機能物質化学, 基盤研究(C), 愛媛大学, The development of organic ferromagnet and superconductor has attracted much attention in the field of material science, and many studies have been performed with great success in recent years. On the other hand, the examples of magnetic superconductors, where the superconducting state and antiferromagnetic or ferromagnetic order coexist in a system are very limited, because of the difficulty in molecular design of the complexes. Especially, the examples of the magnetic superconductor consisting of purely organic compounds have not been reported.In the present work, in order to obtain the organic magnetic conductors, first, we prepared several kinds of iodide salts of verdazyl radical cations (for example, 3-(4- and 3-methylpyridinium)-1,5-diphenylverdazyl radical cations ([p-MePyDV]^+ and [m-MePyDV]^+). These iodide salts were reacted with Li^+[TCNQ]^-, Li^+[Me_2-TCNQ]^-, and [n-Bu_4N]^+[Ni(dmit)_2]^- salts, giving the (1:1) salts of verdazyl cations with TCNQ, Me_2-TCNQ, and Ni(dmit)_2 anions. Several kinds of (1:2) and (1:3) salts of verdazyl cations with TCNQ, Me_2-TCNQ, and Ni(dmit)_2 anions were prepared by the oxidation of the (1:1) salts. Further, the magnetic and electric properties, and crystal structures of these radical salts have been studied. It has been clarified that the eight kinds of salts are new molecular magnetic semiconductors.
  • Ministry of Education, Culture, Sports, Science and Technology, Grants-in-Aid for Scientific Research(特定領域研究), Spin Dynamics of the Anti-Aging Actions by NaturalAntioxidants, Kazuo MUKAI, Kunihiko TAJIMA, Keishi OHARA, Shin-ichi NAGAOKA, Masaki MITO, 特定領域研究, 愛媛大学, Human aging is induced by the reaction of lipid, protein, and nucleic acid with active oxygens and free radicals. Natural antioxidants such as vitamin E (α-, β-, γ-, δ-tocopherol, TocH), ubiquinol, vitamin C, polyphenols (flavones, catechins) etc., which exist in biological systems, scavenge active oxygens and free radicals quickly, and protect the aging. In the present work, the kinetic studies of i) free-radical-scavenging action, ii) tocopherol-regeneration action, and iii) singlet-oxygen-quenching action with the above natural antioxidants were performed, and several interesting results were obtained.1) The aroxyl-radical-scavenging rates (k_s) of vitamin E (α-, β-, γ-, δ-TocH) and ubiquinol were measured in micellar solutions by varying pH, using stopped-flow spectrophotometer. It has been clarified that ubiquinol shows higher and lower free-radical-scavenging activity than a-tocopherol in mitochondria of several tissues (heart, muscle, liver and brain) and in serum, respectively.2) Quenching rates (K_Q) of singlet oxygen (^1O_2) by 7 kinds of flavone derivatives and 4 kinds of catechins have been measured The K_Q values of several kinds of flavones and catechins were found to be larger than those of lipids, amino acids, and DNA. Further, these values are similar to those of a-and y-tocopherol, ubiquinol-10, and plastoquinol model, suggesting that these polyphenols may contribute to the protection of oxidative damage in biological systems, by quenching ^1O_2.3) In order to understand the dynamics of antioxidant actions of vitamin E (α-,β-, γ-, δ-TocH) in biological systems, kinetic study of the formation and decay reactions of vitamin E radicals (α-, β-, γ-, δ-tocopheroxyls, Toc) has been performed in organic solvents, using stopped-flow spectrophotometer. The second-order rate constants (k_f and 2k_d) for the formation and decay reactions of Toc were determined by comparing the observed curves with the simulation ones obtained by the numerical calculation of differential equations related to the above reactions. The k_f values decreased in the order of α-> β-~γ-> δ-TocH, and the 2kd values increased in the order of α-< β-< γ-< δ-Toc in ethanol. The wavelengths of absorption maxima (λmax^1) and molar extinction coefficients (ε_1) of the optical spectra (for example, i = 1~4 for α-Toc.) were determined for these radicals. The scheme of the decay reactions of α-, β-, γ-, δ-Toc radicals has been discussed based on the results obtained.4)The rate constant and activation energy of the regeneration reaction of natural vitamin E by vitamin C were determined with a double-mixingstopped-flow spectrophotometer. The kinetic effect ofmethyl substitution on the aromatic ring of vitamin E radical indicates that partial charge-transfer plays a role in the reaction Since a substantial deuterium kinetic isotope effect was not found, the tunneling effect may not play an important role under the present experimental conditions.
  • Ministry of Education, Culture, Sports, Science and Technology, Grants-in-Aid for Scientific Research(基盤研究(C)), Antioxidant Activity of Natural Antioxidants versus Reactive Oxygen Species in Emulsion Systems and Its Spin-Dynamics, Keishi OHARA, 物理化学, 基盤研究(C), 愛媛大学, In the present study, a kinetic investigation was progressed on the antioxidant reactions versus reactive oxygen species for natural antioxidants, such as vitamin E and catechins, in the emulsion phase by using time-resolved methods based on the fluorescence or ESR detection.1.The second-order rate constant for the scavenging reaction of the model free-radical in vitamin E (VE) emulsion systems was firstly obtained by using the fluorescence-detected stopped-flow method. The result indicates that the rate constants in emulsion systems are different from that in the homogeneous solution. This kinetic approach could also be applicable to the scavenging reaction of other radicals, such as galvinoxyl and DPPH, in emulsion systems.2.For investigating the dynamics of singlet oxygen (^1O_2) in the emulsion systems, the emission (at 1275 nm) from ^1O_2 was measured directly by using a time-resolved near-infrared fluorescence spectrophotometer. In the VE emulsion system, the life-time of ^1O_2 increases with an increase of the concentration of VE, while the VE usually shows 10^7 - 10^8 M^<-1>s^<-1> as the ^1O_2 quenching rate constant in homogeneous solutions. The result suggests that the ^1O_2 dynamics occurs mainly near the oil-droplet of VE in this system.3 The investigation on the spin-dynamics for the short-lived intermediate radials generated by the laser excitation of natural vitamin E and hydroperoxide is progressed by using the time-resolved ESR and transient absorption methods.The results of the present study give the time-resolved tools for investigating the kinetics and the spin-dynamics of the free-radicals and ^1O_2 in emulsion phase, which is a model of biological systems, colloids, food, and drinks. The obtained information for emulsion systems will clarify the unique dynamics in inhomogeneous systems.
  • Ministry of Education, Culture, Sports, Science and Technology, Grants-in-Aid for Scientific Research(基盤研究(C)), Mechanism of Excited-State Proton-Transfer- From Near-Infrared to Soft X-ray -, Shin-ichi NAGAOKA, Keishi OHARA, 物理化学, 基盤研究(C), 愛媛大学
  • Ministry of Education, Culture, Sports, Science and Technology, Grant-in-Aid for Young Scientists (A), CIDEP Spin-probe for Singlet Oxygen Dynamics around Micelles and Biomembranes, Keishi OHARA
  • Ministry of Education, Culture, Sports, Science and Technology, Grants-in-Aid for Scientific Research(基盤研究(B)), Natural Antioxidants : Their Activities and Action Mechanism, Kazuo MUKAI, Keish OHARA, Shin-ichi NAGAOKA, 機能・物性・材料, 基盤研究(B), 愛媛大学, In the present work, we measured the rate constants of the reaction of peroxyl, tocopheroxyl, and aroxyl free radicals with natural antioxidants, such as catechins, caffeic acids and related compounds in homogeneous and micellar solutions, by using oxygen absorption method, stopped-flow spectrophotometer, and time-resolved ESR method. We have succeeded in obtaining the following interesting results :l) Detailed kinetic studies have been performed for the reaction of aroxyl (ArO ・) and 5,7-diisopropyltocopheroxyl (Toc ・ ) radicals with catechin, epicatechin, and related antioxidants in homogeneous and micellar solutions. The structure-activity relationship in the scavenging reaction of free radicals by catechin and epicatechin in solution was discussed. It has been found that catechin and epicatechin have high activity in vitamin E regeneration.2) The antioxidant activity of curcumin (1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione) was determined by inhibition of controlled initiation of styrene oxidation. Synthetic nonphenolic curcumins exhibited no antioxidant activity, therefore, curcumin is a classical phenolic chain-breaking antioxidant, donating H atoms from the phenolic groups not the CH_2 group as has been suggested (Jovanovic et al. J.Am. Chem. Soc., 121, 9677 (1999)).3) Studies of the kinetics of the proton- or hydrogen-transfer reactions concerning vitamin E in solutions and in micellar dispersions by means of stopped-flow and absorption spectroscopy indicated that proton tunneling plays an important role in the antioxidant and regeneration reactions that are advantageous in vivo but not as a part of the harmful prooxidant action.
  • Ministry of Education, Culture, Sports, Science and Technology, Grants-in-Aid for Scientific Research(基盤研究(C)), A Study of Excited -State-Proton-Transfer Reaction, Shin-ichi NAGAOKA, Keishi OHARA, Kazuo MUKAI, 物理化学, 基盤研究(C), 愛媛大学, Proton transfer is a very simple chemical process readily accessible to both accurate measurement and quantitative theoretical analysis. We have constructed a simple theoretical model of the excited-state-proton-transfer, a model based on the nodal pattern of the wave function. In this project we have studied the application of our nodal-plane model to the following three problems.1. The substituent effect and the electronic-state dependence in the excited-state-intramolecular-proton-transfer (ESIPT) of o-hydroxybenzladehydes.2. The substituent-position effect in ESIPT of 2-(o-hydroxyaryl)benzazoles : Although both 2-(2-hydroxy- 3-aryl)benzazole and 2-(1-hydroxy- 2-aryl)benzazole consist of an aryl moiety, a benzazol-2-yl group, and an Oil group, their emission properties are very different.3. The substituent and solvent effects in ESIPT of aminoanthraquinones : The singlet-triplet energy-gap of the proton-transferred form is much less than that in the normal form.The experimental results obtained on the above three problems strongly support our nodal-plane model.Furthermore, we synthesized a bridged molecule of vitamin E and quinones, and studied the radical scavenging reaction of vitamin E.It is interesting that the microscopic electron behavior could manifest itself in the macroscopic vital-function.Although our nodal-plane model is a qualitative one, it allows us to recognize the important features of ESIPT immediately and provides useful information about the reaction mechanisms. Our nodal-plane model is applicable to photochemical reactions in various excited states of various molecules. Many chemists have cited it, and the usefulness of our explanation is recognized by many researchers.
  • Ministry of Education, Culture, Sports, Science and Technology, Grants-in-Aid for Scientific Research(基盤研究(B)), Syntheses of New Verdazyl Radicals and Mechanism of Appearance of Genuine Organic Ferromagnetism and Weak Ferromagnetism, Kazuo MUKAI, Keisi OHARA, 機能・物性・材料, 基盤研究(B), 愛媛大学, In the present work, about 50 kinds of new organic verdazyl radical crystals have been prepared. From the results of the measurements of magnetic susceptibility, ac magnetic susceptibility, heat capacity arid ESR and the X-ray analyses, we have succeeded in obtaining the following compounds having interesting magnetic properties.1) Finding of three kinds of new organic ferromagnet (p-CDTV, p-CDpOV and p-MeDpOV) and the mechanism of appearance of ferromagnetism.2) Finding of two kinds of new organic weak ferromagnet (TOV and p-CyDpTV).3) Doping effect of nonmagnetic impurities on weak ferromagnet, TOV.4) Finding of two kinds of new organic antiferromagnet (p-NTV and p-BDpTV).5) Finding of a new spin-Peierls transition compound (p-CyDOV) and study of its magnetic phase diagram.6) The study of doping effect of magnetic and nonmagnetic impurities on the spin-Peierls transition of p-CyDOV radical crystal.7) Finding of a new verdazyl spin frustration compound, p-FPDV.8) Magnetism of molecular complexes between verdazyl radical and electron acceptor (TCNQ and TCNQF_4).9) The study of doping effect of magnetic impurities on quasi-one dimensional Heisenberg organic ferromagnet (p-CDpOV) and antiferromagnet (p-BDpOV).
  • Ministry of Education, Culture, Sports, Science and Technology, Grants-in-Aid for Scientific Research(国際学術研究), FT-ESR Study of Initial Process of Phtochemical Reactions, Noboru HIROTA, Keishi OHARA, Kouichi NAKAGAWA, Masahide TERAZIMA, WILLIGEN Han, WILLIGEN Hans Van, Hans von WILLIGEN, 国際学術研究, 京都大学, At the international symposium on spin and magnetic field effects held in Novosibirsk in August, 1996 Hirota, van Willigen and Ohara discussed the detailed plan of the cooperative work. It was decided that the initial processes of photochemical reactions of xanthone of which a number of unsolved problems exist should be studied by FT-EPR method. Following this discussion, Ohara went to Boston in September to make FT-EPR measurements. In this work he obtained the following results.1) Emissive polarization found in xanthone/2-propanol is mainly determined by the hydrogen abstraction of xanthone and its mechanism is radical pair mechanism (RPM).2) The rise of the absorptive polarization observed in xanthone/2-propanol +HィイD22ィエD2O +HCl is very rapid determined by the time -resolution of the spectrometer and the mechanism is likely to be triplet mechanism (TM). However, the intensity of the polarization is very weak.In November, Hirota made further measurement in Boston and examined the effect of the concentration of HCl on the polarization. It was found that inversion of the polarization of the hydroxypropyl radical from E to A takes place at a relatively low concentration of HCl. Moreover, it was found that the polarization of the xanthone ketyl radical showed an inversion from A to E. It was though that additional transient absorption experiments are needed to clarify the initial processes in the photochemistry of xanthone and work along this line was tried in Kyoto with Prof. van Willigen. However, this work has not been completed yet, and further work will be continued.In addition to the above work Nakagawa made FT-EPR work on the hydrated electron in the SDS micelle produced by the photoionization of phenothiazine and its derivatives. He obtained detailed information about the phase of the CIDEP signal of the hydrated electron, dynamics of disappearance and quenching of the CIDEP signal of the hydrated electron.


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