KINDAI UNIVERSITY


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YONEZAWA Yasushige

Profile

FacultyInstitute of Advanced Technology / Graduate School of Biology-Oriented Science and Technology
PositionProfessor
Degree
Commentator Guidehttps://www.kindai.ac.jp/meikan/341-yonezawa-yasushige.html
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Last Updated :2020/09/30

Education and Career

Academic & Professional Experience

  •   2011 04 ,  - 2015 , Kindai University
  •   2002 12 ,  - 2011 03 , Institute for Protein Research, Osaka University
  •   1992 04 ,  - 2002 12 , Tsukuba College of Technology

Research Activities

Research Areas

  • Life sciences, Biophysics

Research Interests

  • QCD

Published Papers

  • Mutational effects of Cys113 on structural dynamics of Pin1, Teikichi Ikura, Yasushige Yonezawa, Nobutoshi Ito, Biophysics and Physicobiology, Biophysics and Physicobiology, 16, 452 - 465, Sep. 2019 , Refereed
  • Loosening of side-chain packing associated with perturbations in peripheral dynamics induced by the D76N mutation of β2-microglobulin revealed by pressure-NMR and molecular dynamic simulations, Kazumasa Sakurai, Ryosuke Tomiyama, Takuma Shiraki, Yasushige Yonezawa, Biomolecules, Biomolecules, 9(9), 491, Sep. 2019 , Refereed
  • Autoencoder-based detection of dynamic allostery triggered by ligand binding based on molecular dynamics, Y Tsuchiya, K Taneishi, Y Yonezawa, Journal of chemical information and modeling, Journal of chemical information and modeling, Aug. 2019 , Refereed
  • Allosteric Activation of Cytochrome P450 3A4 by Efavirenz Facilitates Midazolam Binding, Tomohiko Ichikawa, Hirofumi Tsujino, Takahiro Miki, Masaya Kobayashi, Chiaki Matsubara, Sara Miyata, Taku Yamashita, Kohei Takeshita, Yasushige Yonezawa, Tadayuki Uno, Xenobiotica, Xenobiotica, 1 - 10, Dec. 2018 , Refereed
  • Free Energy Reconstruction from Logarithmic Mean-Force Dynamics Using Multiple Nonequilibrium Trajectories, Tooro Morishita, Yasushige Yonezawa, Journal of Chemical Theory and Computation, Journal of Chemical Theory and Computation, 13(7), Aug. 2017 , Refereed
  • Substrate recognition of N,N '-diacetylchitobiose deacetylase from Pyrococcus horikoshii, Tsutomu Nakamura, Yasushige Yonezawa, Yuko Tsuchiya, Mayumi Niiyama, Kurumi Ida, Maki Oshima, Junji Morita, Koichi Uegaki, JOURNAL OF STRUCTURAL BIOLOGY, JOURNAL OF STRUCTURAL BIOLOGY, 195(3), 286 - 293, Sep. 2016 , Refereed
    Summary:Enzymes of carbohydrate esterase (CE) family 14 catalyze hydrolysis of N-acetyl groups at the non-reducing end of the N-acetylglucosamine (GlcNAc) residue of chitooligosaccharides or related compounds. N,N'-diacetylchitobiose deacetylase (Dac) belongs to the CE-14 family and plays a role in the chitinolytic pathway in archaea by deacetylating N,N'-diacetylchitobiose (GlcNAc(2)), which is the end product of chitinase. In this study, we revealed the structural basis of reaction specificity in CE-14 deacetylases by solving a crystal structure of Dac from Pyrococcus horikoshii (Ph-Dac) in complex with a novel reaction intermediate analog. We developed 2-deoxy-2-methylphosphoramido-D-glucose (MPG) as the analog of the tetrahedral oxyanion intermediate of the monosaccharide substrate GlcNAc. The crystal structure of Ph-Dac in complex with MPG demonstrated that Arg92, Asp115, and His152 side chains interact with hydroxyl groups of the glucose moiety of the non-reducing-end GlcNAc residue. The amino acid residues responsible for recognition of the MPG glucose moiety are spatially conserved in other CE-14 deacetylases. Molecular dynamics simulation of the structure of the Ph-Dac-GlcNAc(2) complex indicated that the reducing GlcNAc residue is placed in a large intermolecular cleft and is not involved with specific interactions with the enzyme. This observation was consistent with results indicating that Ph-Dac displayed similar kinetic parameters for both GlcNAc and GlcNAc(2). This study provides the structural basis of reaction-site specificity of Dac and related CE-14 enzymes. (C) 2016 Elsevier Inc. All rights reserved.
  • Electronic structures of a [4Fe?4S] cluster, [Fe4S4(SCH3)3(CH3COO)], in dark-operative protochlorophyllide oxidoreductase (DPOR), Chem. Phys. Lett., Chem. Phys. Lett., 501, 598 - 602, Mar. 2011
  • Electronic structures of a [4Fe-4S] cluster, [Fe4S4(SCH3)3(CH3COO)], in dark-operative protochlorophyllide oxidoreductase (DPOR), Yu Takano, Yasushige Yonezawa, Yuichi Fujita, Genji Kurisu, Haruki Nakamura, Chemical Physics Letters, Chemical Physics Letters, 503(4-6), 296 - 300, Feb. 17 2011 , Refereed
  • Simple and effective application of the Wang-Landau method for multicanonical molecular dynamics simulation, Journal of Chemical Physics, Journal of Chemical Physics, 134(024), 109, Jan. 2011 , Refereed
  • Study on the Free Energy Landscape of Alanine-dimer peptide in Explicit Water using the Force-switching Wolf Method, JSBi2010, JSBi2010, Dec. 2010 , Refereed
  • Reconstruction of 2D Free-energy Landscape of Protein from Multiscale Simulation, JSBi2010, JSBi2010, Dec. 2010 , Refereed
  • Verifying trivial parallelization of multicanonical molecular dynamics for conformational sampling of a polypeptide in explicit water, Chem. Phys. Lett., Chem. Phys. Lett., 15(30), 110 - 118, Apr. 2009 , Refereed
  • Verifying trivial parallelization of multicanonical molecular dynamics for conformational sampling of a polypeptide in explicit water, Higo Junichi, Kamiya Narutoshi, Sugihara Takanori, Yonezawa Yasushige, Nakamura Haruki, Chemical Physics Letters, Chemical Physics Letters, 473(4-6), 326, 2009 , Refereed
  • Opal OP: An Extensible Grid-Enabling Wrapping Approach for Legacy Apprications, 3rd Workshop on Grid Computing & Applications (GCA2007), 3rd Workshop on Grid Computing & Applications (GCA2007), Jun. 2007 , Refereed
  • Flexible docking of an amyloid-forming peptide from beta(2)-microglobulin, Daron M. Standley, Yasushige Yonezawa, Yuji Goto, Haruki Nakamura, FEBS LETTERS, FEBS LETTERS, 580(26), 6199 - 6205, Nov. 2006 , Refereed
    Summary:Using an all-atom, molecular dynamics-based, flexible docking method, the tertiary and quaternary structures of protofilaments of the "K3' fragment from beta(2)-microglobulin (residues Ser20-Lvs41) were predicted at low pH in a continuous mixture of water and 2,2,2-trifluoroethanol (TFE). Tetramers with energies very close to the global minimum were produced with C, root-mean square deviation values under 4 A over 88 residues compared to a recently solved SSNMR structure. The most accurate model distinguishes itself from other low-energy solutions in that it shows high structural similarity to another known fold, the parallel beta-helix, in agreement with models proposed previously by several other groups. The method achieves efficiency without loss of generality or atomic detail by enforcing local symmetry on the individual peptides, rewarding intermolecular contacts, and iteratively building up the protofilaments by successively doubling the number of chains. Solvent effects were included in the model by treating the dielectric constant and surface tension as functions of the TFE concentration. In order to understand the physical basis for the stabilizing effects of TFE, the TFE concentration was varied from 0% to 50% (v/v) and a peak in stability was observed at 16%, where the polar and hydrophobic terms cancel out and close to the experimentally determined value of 20%. (c) 2006 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.
  • Molecular dynamics simulation study on water associated with pi-electrons of benzene by using QM/MM potential, Yasushige Yonezawa, Kazuto Nakata, Toshikazu Takada, Haruki Nakamura, CHEMICAL PHYSICS LETTERS, CHEMICAL PHYSICS LETTERS, 428(1-3), 73 - 77, Sep. 2006 , Refereed
    Summary:The benzene-water system is a model for understanding the interactions within bio-molecules. We performed a series of molecular dynamics simulations with hybrid QM/MM potentials, where benzene and one of the water molecules were treated quantum mechanically, while other waters were treated by molecular mechanics. The umbrella sampling method was employed to realize effective sampling and the potential of mean force (PMF) was obtained for water associated with benzene using the weighted histogram analysis method. The resulting PMF was then compared with that derived by a conventional molecular mechanics method and was found to be in accord with the experimental result. (c) 2006 Elsevier B.V. All rights reserved.
  • Neutron Crystallography of Hen Egg-White Lysozyme at pH4.9., M. Maeda, S. Fujiwara, Y. Yonezawa, N. Niimura, J. Phy. Soc. Jpn Suppl. A., J. Phy. Soc. Jpn Suppl. A., 403 - 405, Nov. 2001 , Refereed
  • Search of J/ψ production in the two-photon process at TRISTAN, E. K. Matsuda, S. Uehara, I. Nakano, N. Tamura, K. Abe, K. Amako, Y. Arai, Y. Asano, M. Chiba, Y. Chiba, M. Daigo, M. Fukawa, Y. Fukushima, J. Haba, H. Hamasaki, Y. Hemmi, M. Higuchi, T. Hirose, Y. Homma, N. Ishihara, Y. Iwata, J. Kanzaki, R. Kikuchi, T. Kondo, T. T. Korhonen, H. Kurashige, T. Matsui, K. Miyake, S. Mori, Y. Nagashima, Y. Nakagawa, T. Nakamura, S. Odaka, K. Ogawa, T. Ohama, T. Ohsugi, H. Ohyama, K. Okabe, A. Okamoto, A. Ono, J. Pennanen, H. Sakamoto, M. Sakuda, M. Sato, N. Sato, M. Shioden, J. Shirai, T. Sumiyoshi, Y. Takada, F. Takasaki, M. Takita, D. Tatsumi, K. Tobimatsu, T. Tsuboyama, Y. Unno, T. Watanabe, Y. Watase, F. Yabuki, Y. Yamada, T. Yamagata, Y. Yonezawa, H. Yoshida, K. Yusa, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 501(3-4), 183 - 190, Mar. 08 2001 , Refereed
    Summary:An experimental study was carried out for J/ψ production in a two-photon process using the VENUS detector at the TRISTAN e+e- collider. The study was based on 357 pb-1 data at an average e+e- center-of-mass energy of 58 GeV. No significant signal was observed, and the upper limit of the production cross section was obtained. © 2001 Published by Elsevier Science B.V.
  • Precise measurement of the total hadronic cross section in e(+)e(-) annihilation at root s = 57.77 GeV, K Yusa, H Hamasaki, S Mori, T Tsuboyama, K Abe, K Amako, Y Arai, Y Asano, M Chiba, Y Chiba, M Daigo, M Fukawa, Y Fukushima, J Haba, Y Hemmi, M Higuchi, T Hirose, Y Homma, N Ishihara, Y Iwata, J Kanzaki, R Kikuchi, T Kondo, TT Korhonen, H Kurashige, EK Matsuda, T Matsui, K Miyake, Y Nagashima, Y Nakagawa, T Nakamura, Nakano, I, S Odaka, K Ogawa, T Ohama, T Ohsugi, H Ohyama, K Okabe, A Okamoto, A Ono, J Pennanen, H Sakamoto, M Sakuda, M Sato, N Sato, M Shioden, J Shirai, T Sumiyoshi, Y Takada, F Takasaki, M Takita, N Tamura, D Tatsumi, K Tobimatsu, S Uehara, Y Unno, T Watanabe, Y Watase, F Yabuki, Y Yamada, T Yamagata, Y Yonezawa, H Yoshida, PHYSICS LETTERS B, PHYSICS LETTERS B, 447(1-2), 167 - 177, Feb. 1999 , Refereed
    Summary:The total hadronic cross section in e(+)e(-) annihilation has been measured at root s = 57.77 GeV using 290 pb(-1) data sample collected with the VENUS detector at KEK TRISTAN. The cross section obtained is 140.3 +/- 1.8 pb for s'/s greater than or equal to 0.5, where s' is the square of the invariant mass of the final state hadrons. The present result together with the recent results from the LEP collaborations is used to determine the hadronic gamma - Z(0) interference parameter, j(had)(tot), to be 0.196 +/- 0.083. The result is in good agreement with the Standard Model prediction of 0.220. (C) 1999 Elsevier Science B.V. All rights reserved.
  • Precise measurement of the e+e- →μ+μ- reaction at √s=57.77GeV., Yasushige Yonezawa, Phys. Rev. D, Phys. Rev. D, 57, 5345 - 5362, Nov. 1998 , Refereed
  • Measurement of the charged multiplicity of bottom and light quark events in e+e- annihilation at √s=58GeV., Yasushige Yonezawa, Phys. Lett.B, Phys. Lett.B, 423, 185 - 192, Jul. 1997 , Refereed
  • Measurement of τ polarization in e+e- annihilation at √s = 58 GeV, H. Hanai, J. Haba, K. Abe, K. Amako, Y. Arai, T. Arima, Y. Asano, M. Chiba, Y. Chiba, M. Daigo, M. Fukawa, Y. Fukushima, H. Hamasaki, Y. Hemmi, M. Higuchi, T. Hirose, Y. Homma, N. Hosoda, N. Ishihara, Y. Iwata, J. Kanzaki, R. Kikuchi, T. Kondo, T. T. Korhonen, H. Kurashige, E. K. Matsuda, T. Matsui, M. Miura, K. Miyake, S. Mori, Y. Nagashima, Y. Nakagawa, T. Nakamura, I. Nakano, S. Odaka, K. Ogawa, T. Ohama, T. Ohsugi, H. Ohyama, K. Okabe, A. Okamoto, A. Ono, J. Pennanen, H. Sakamoto, M. Sakuda, M. Sato, N. Sato, M. Shioden, J. Shirai, T. Sumiyoshi, Y. Takada, F. Takasaki, M. Takita, N. Tamura, D. Tatsumi, K. Tobimatsu, T. Tsuboyama, S. Uehara, Y. Unno, T. Watanabe, Y. Watase, F. Yabuki, Y. Yamada, T. Yamagata, Y. Yonezawa, H. Yoshida, K. Yusa, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 403(1-2), 155 - 162, Jun. 19 1997 , Refereed
    Summary:The polarization of τ leptons in the reaction e+e- → τ+τ- has been measured using a e+e- collider, TRISTAN, at the center-of-mass energy of 58 GeV. From the kinematical distributions of daughter particles in τ → eνν̄, μνν̄, ρν or π(K)ν decays, the average polarization of τ- and its forward-backward asymmetry have been evaluated to be 0.012±0.058 and 0.029±0.057, respectively. © 1997 Published by Elsevier Science B.V.
  • D*+/- inclusive production in two-photon process at root s=58 GeV in TRISTAN, H Ohyama, K Abe, K Amako, Y Arai, Y Asano, M Chiba, Y Chiba, M Daigo, M Fukawa, Y Fukushima, J Haba, H Hamasaki, H Hanai, Y Hemmi, M Higuchi, T Hirose, Y Homma, N Ishihara, Y Iwata, J Kanzaki, R Kikuchi, T Kondo, TT Korhonen, H Kurashige, EK Matsuda, T Matsui, K Miyake, S Mori, Y Nagashima, Y Nakagawa, T Nakamura, Nakano, I, S Odaka, K Ogawa, T Ohama, T Ohsugi, K Okabe, A Okamoto, A Ono, J Pennanen, H Sakamoto, M Sakuda, M Sato, N Sato, M Shioden, J Shirai, T Sumiyoshi, Y Takada, F Takasaki, M Takita, N Tamura, D Tatsumi, K Tobimatsu, T Tsuboyama, S Uehara, Y Unno, T Watanabe, Y Watase, F Yabuki, Y Yamada, T Yamagata, Y Yonezawa, H Yoshida, K Yusa, ZEITSCHRIFT FUR PHYSIK C-PARTICLES AND FIELDS, ZEITSCHRIFT FUR PHYSIK C-PARTICLES AND FIELDS, 75(2), 209 - 214, Jun. 1997 , Refereed
    Summary:Using the VENUS detector at TRISTAN we have investigated the charm-quark production by detecting D*(+/-) mesons in the two-photon process of e(+)e(-) collisions. The study has confirmed that the charm-quark production rate is larger than that predicted from direct c (c) over bar production alone. The distribution of the transverse momentum of the D*(+/-) mesons and the forward energy flow associated with the D*(+/-) production suggest that the main part of the observed excess comes from the contribution of a resolved photon process.
  • Study of inclusive baryon antibaryon pair production of rho or Lambda in two-photon processes, S Uehara, K Abe, K Amako, Y Arai, T Arima, Y Asano, M Chiba, Y Chiba, M Daigo, M Fukawa, Y Fukushima, J Haba, H Hamasaki, H Hanai, Y Hemmi, M Higuchi, F Hinode, T Hirose, Y Homma, N Hosoda, N Ishihara, Y Iwata, J Kanzaki, R Kikuchi, T Kondo, TT Korhonen, H Kurashige, EK Matsuda, T Matsui, M Miura, K Miyake, S Mori, Y Nagashima, Y Nakagawa, T Nakamura, Nakano, I, S Odaka, K Ogawa, T Ohama, T Ohsugi, H Ohyama, K Okabe, A Okamoto, A Ono, T Oyama, J Pennanen, H Sakamoto, M Sakuda, M Sato, N Sato, M Shioden, J Shirai, M Shirakata, T Sumiyoshi, Y Takada, F Takasaki, M Takita, N Tamura, D Tatsumi, K Tobimatsu, T Tsuboyama, Y Unno, T Watanabe, Y Watase, F Yabuki, Y Yamada, T Yamagata, Y Yonezawa, H Yoshida, K Yusa, ZEITSCHRIFT FUR PHYSIK C-PARTICLES AND FIELDS, ZEITSCHRIFT FUR PHYSIK C-PARTICLES AND FIELDS, 69(4), 597 - 606, Feb. 1996 , Refereed
    Summary:Inclusive baryon-antibaryon pair production was studied in two-photon events which were collected at the e(+)e(-) collider TRISTAN, and correspond to an integrated luminosity of 303 pb(-1). Correlations between a baryon and an antibaryon were studied for their flavors (p or Lambda) and their momentum vectors. The experimental results were compared with the expectations from a jet-fragmentation Monte Carlo simulation. We have found that although the ratios of the cross sections of different baryon-flavor combinations are consistent with the Monte Carlo expectations, the cross section shows an excess over the Monte Carlo expectation in a low invariant-mass region of final-state particles at large angles, that indicates a significant contribution from higher-order QCD or non-perturbative effects. The experimental data show no narrow azimuthal-angle correlation, which is expected from a jet-fragmentation Monte Carlo. A search for exclusive Lambda pair production has also been made. We have no candidates and have obtained the upper limit for the cross section.
  • Kaonic Hydrogen X-ray Experiment at KEK., M. Iwasaki, K.Barlett, G.A.Beer, D.R.Gill, R.S.Hayano, T.M.Ito, L.Lee, F.E.Maas, G.Mason, S.N.Nakamura, A.Olin, H.Outa, M.salomon, R.Seki, T.Taniguchi, T.P.Terada, G.Trayling, E.Widmann, Y.Yamashita, S.Yen, Y.Yonezawa, Nuclear Physics A, Nuclear Physics A, 585, 239 - 246, Aug. 1995 , Refereed
  • Study of π+π− Pair Production in a Two-Photon Process at TRISTAN: VENUS Collaboration, Fumiaki Yabuki, Masami Chiba, Tachishige Hirose, Naoyasu Hosoda, Takashi Oyama, Koya Abe, Jimmy Macnaughton, Katsuya Amako, Yasuo Arai, Mineo Fukawa, Yasutaka Fukushima, Fujio Hinode, Nobuhiro Ishihara, Junichi Kanzaki, Takahiko Kondo, Timo T. Korhonen, Takayuki Matsui, Shigeru Odaka, Kazuo Ogawa, Taro Ohama, Makoto Sakuda, Nobuaki Sato, Junpei Shirai, Takayuki Sumiyoshi, Fumihiko Takasaki, Toru Tsuboyama, Sadaharu Uehara, Yoshinobu Unno, Yoshiyuki Watase, Yoshikazu Yamada, Masashi Shirakata, Nobuyuki Kanematsu, Tatsumi Arima, Yuzo Asano, Makoto Miura, Shigeki Mori, Yoshihisa Takada, Yasuo Chiba, Motomasa Daigo, Junji Haba, Yorikiyo Nagashima, Masato Takita, Nobuyuki Kanda, Andreas Krüger, Atsumu Suzuki, Hiroyuki Takaki, Yasuo Hemmi, Ryusaburo Kikuchi, Hisaya Kurashige, Kozo Miyake, Atsushi Okamoto, Hiroshi Sakamoto, Masato Higuchi, Minoru Sato, Yasuhiro Homma, Timo T. Korhonen, Emiko Kanatani Matsuda, Norio Tamura, Teruo Nakamura, Itsuo Nakano, Takashi Ohsugi, Hiroshi Ohyama, Atsuo Ono, Masaomi Shioden, Keijiro Tobimatsu, Taketora Yamagata, Yasushige Yonezawa, Hajime Yoshida, Michiaki Utsumi, Journal of the Physical Society of Japan, Journal of the Physical Society of Japan, 64(2), 435 - 447, 1995 , Refereed
    Summary:We measured the cross section for the γγ→π+π− process in the pion pair invariant mass range of 1.0–1.5 GeV/c2 with the VENUS detector at TRISTAN. The γγ decay width of the f2 (1270) resonance was obtained by using Vermaseren's model and a partial wave analysis. The results from both analyses were in good agreement. The partial wave analysis indicated the presence of a J=0 component around at 1.2 GeV/c2 with a resonance-like structure. © 1995, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.
  • A study of single photon production in e+ e- annihilation at s = 58 GeV, N. Hosoda, K. Abe, K. Amako, Y. Arai, T. Arima, Y. Asano, M. Chiba, Y. Chiba, M. Daigo, M. Fukawa, Y. Fukushima, J. Haba, H. Hanai, Y. Hemmi, M. Higuchi, F. Hinode, T. Hirose, Y. Homma, Y. Hoshi, N. Ishihara, Y. Iwata, N. Kanda, N. Kanematsu, J. Kanzaki, R. Kikuchi, T. Kondo, T. T. Korhonen, A. Krüger, H. Kurashige, J. MacNaughton, E. K. Matsuda, T. Matsui, M. Miura, K. Miyake, S. Mori, Y. Nagashima, Y. Nakagawa, T. Nakamura, I. Nakano, S. Odaka, T. Ohama, T. Ohsugi, A. Ohyama, A. Okamoto, A. Ono, T. Oyama, H. Sakamoto, M. Sakuda, M. Sato, N. Sato, M. Shioden, J. Shirai, M. Shirakata, T. Sumiyoshi, A. Suzuki, Y. Takada, H. Takaki, F. Takasaki, M. Takita, N. Tamura, K. Tobimatsu, T. Tsuboyama, S. Uehara, Y. Unno, M. Utsumi, Y. Watase, F. Yabuki, Y. Yamada, Y. Yamamoto, T. Yamagata, Y. Yonezawa, H. Yoshida, Physics Letters B, Physics Letters B, 331(1-2), 211 - 216, Jun. 30 1994 , Refereed
    Summary:We have studied single photon production in e+ e- annihilation based on a data sample corresponding to an integrated luminosity of 164.1 pb-1 at s=58 GeV. The single photon yield is consistent with the prediction of the standard model with three light neutrino species. No anomalous signal has been observed. From this result left- and right-handed scalar electrons in the mass degenerate case are excluded at 90% CL below 44.4 GeV/c2 for the massless photino. © 1994.
  • Search for a light scalar top squark in e+e- reactions at Ec.m.=58 GeV, J. Shirai, T. Ohmoto, K. Abe, K. Amako, Y. Arai, T. Arima, Y. Asano, M. Chiba, Y. Chiba, M. Daigo, M. Fukawa, Y. Fukushima, J. Haba, H. Hanai, Y. Hemmi, M. Higuchi, F. Hinode, T. Hirose, Y. Homma, N. Hosoda, N. Ishihara, Y. Iwata, N. Kanda, N. Kanematsu, J. Kanzaki, R. Kikuchi, T. Kondo, T. T. Korhonen, A. E. Krüger, H. Kurashige, J. MacNaughton, E. K. Matsuda, T. Matsui, M. Miura, K. Miyake, S. Mori, Y. Nagashima, Y. Nakagawa, T. Nakamura, I. Nakano, S. Odaka, K. Ogawa, T. Ohama, T. Ohsugi, H. Ohyama, A. Okamoto, A. Ono, T. Oyama, H. Sakamoto, M. Sakuda, M. Sato, N. Sato, M. Shioden, M. Shirakata, T. Sumiyoshi, A. Suzuki, Y. Takada, H. Takaki, F. Takasaki, M. Takita, N. Tamura, K. Tobimatsu, T. Tsuboyama, S. Uehara, Y. Unno, M. Utsumi, Y. Watase, F. Yabuki, Y. Yamada, T. Yamagata, Y. Yamamoto, Y. Yonezawa, H. Yoshida, Physical Review Letters, Physical Review Letters, 72(21), 3313 - 3316, 1994 , Refereed
    Summary:A search has been made for a light scalar top squark (t1), which has remained unexcluded by previous e+e- experiments up to the Z0 pole. By assuming the decay t1→c+Z1 (lightest neutralino), e+e- annihilation data at Ec.m.=58 GeV have been analyzed. The number of events comprising large-acoplanarity particle groups is consistent with that expected from known processes. We excluded t1 in the mass range 7.6-28.0 GeV/c2 and Z1 with a mass very close to the kinematical limit at the 95% C.L. © 1994 The American Physical Society.
  • A STUDY OF THE CHARM AND BOTTOM QUARK PRODUCTION IN E+E- ANNIHILATION AT ROOT-S=58 GEV USING PROMPT ELECTRONS, K ABE, K AMAKO, Y ARAI, T ARIMA, Y ASANO, M CHIBA, Y CHIBA, M DAIGO, M FUKAWA, Y FUKUSHIMA, J HABA, Y HEMMI, M HIGUCHI, F HINODE, T HIROSE, Y HOMMA, Y HOSHI, N HOSODA, N ISHIHARA, E KANATANI, N KANDA, N KANEMATSU, J KANZAKI, R KIKUCHI, T KONDO, TT KORHONEN, A KRUGER, H KURASHIGE, J MACNAUGHTON, T MATSUI, M MIURA, K MIYAKE, S MORI, Y NAGASHIMA, T NAKAMURA, NAKANO, I, S ODAKA, K OGAWA, T OHAMA, T OHSUGI, H OHYAMA, A OKAMOTO, A ONO, T OYAMA, H SAKAMOTO, M SAKUDA, M SATO, N SATO, M SHIODEN, J SHIRAI, M SHIRAKATA, T SUMIYOSHI, A SUZUKI, Y TAKADA, H TAKAKI, F TAKASAKI, M TAKITA, N TAMURA, D TATSUMI, K TOBIMATSU, T TSUBOYAMA, S UEHARA, Y UNNO, M UTSUMI, Y WATASE, F YABUKI, Y YAMADA, T YAMAGATA, Y YONEZAWA, H YOSHIDA, PHYSICS LETTERS B, PHYSICS LETTERS B, 313(1-2), 288 - 298, Aug. 1993 , Refereed
    Summary:We have studied c (charm) and b (bottom) quark production at the TRISTAN energy region by tagging prompt electrons from the semileptonic decays. Electrons were identified over a wide momentum range between 1 and 29 GeV/c by a transition-radiation-detector in addition to a lead-glass calorimeter. The production cross sections of c and b quarks and the mean values of the fragmentation functions for c and b quarks were obtained as sigma(c) = 55.9 +/- 8.8 (stat.) +/- 7.9 (syst.) pb, sigma(b) = 13.1 +/- 2.9(stat.) +/- 1.0(syst.) pb, [x(c)] = 0.44 +/- 0.08 (stat.) +/- 0.04(syst.) and [x(b)] = 0.72 +/- 0.12(stat.) +/- 0.08(syst.), respectively. The forward-backward asymmetries of the c and b quarks were also measured to be -0.57 +/- 0.16(stat.) +/- 0.06(syst.) and -0.64 +/- 0.26(stat.) +/- 0.07(syst.), respectively. Both the cross sections and the forward-backward asymmetries of the c and b quarks are consistent with the standard model.
  • SEARCH FOR HEAVY NEUTRAL SPINLESS PARTICLES USING E+E--]E+E- AND E+E--] GAMMA-GAMMA REACTIONS IN THE CM ENERGY-RANGE BETWEEN 54 AND 64 GEV, K ABE, K AMAKO, Y ARAI, T ARIMA, Y ASANO, M CHIBA, Y CHIBA, M DAIGO, M FUKAWA, Y FUKUSHIMA, J HABA, Y HEMMI, M HIGUCHI, F HINODE, T HIROSE, Y HOMMA, Y HOSHI, N HOSODA, N ISHIHARA, E KANATANI, N KANDA, N KANEMATSU, J KANZAKI, R KIKUCHI, T KONDO, TT KORHONEN, AE KRUGER, H KURASHIGE, J MACNAUGHTON, T MATSUI, M MIURA, K MIYAKE, S MORI, Y NAGASHIMA, T NAKAMURA, NAKANO, I, S ODAKA, K OGAWA, T OHAMA, T OHSUGI, H OHYAMA, A OKAMOTO, A ONO, T OYAMA, H SAKAMOTO, M SAKUDA, M SATO, N SATO, M SHIODEN, J SHIRAI, M SHIRAKATA, T SUMIYOSHI, A SUZUKI, Y TAKADA, H TAKAKI, F TAKASAKI, M TAKITA, N TAMURA, K TOBIMATSU, T TSUBOYAMA, S UEHARA, Y UNNO, M UTSUMI, Y WATASE, F YABUKI, Y YAMADA, T YAMAGATA, Y YONEZAWA, H YOSHIDA, PHYSICS LETTERS B, PHYSICS LETTERS B, 302(1), 119 - 124, Mar. 1993 , Refereed
    Summary:Heavy neutral spinless particles are searched for using e+ e- collision data of CM energies between 54 and 64 GeV, collected with the VENUS detector at TRISTAN. The existence of such a particle might explain the anomalous e+e- --> l+l-gammagamma reaction recently reported by a LEP experiment. Negative results lead to constraints on the partial decay width of such particles to electrons: in narrow resonance cases, GAMMA(ee) < 1 MeV from Bhabha scattering data and GAMMA(ee)B(gammagamma) < 3 keV from gammagamma production data at the 95% CL for masses around 59 GeV/c2.
  • Particle spectrum in gluon jets produced in e+e- annihilations at s around 58 GeV, H. Takaki, J. Haba, K. Abe, K. Amako, Y. Arai, T. Arima, Y. Asano, M. Chiba, Y. Chiba, M. Daigo, M. Fukawa, Y. Fukushima, Y. Hemmi, M. Higuchi, F. Hinode, T. Hirose, Y. Homma, Y. Hoshi, N. Hosoda, N. Ishihara, E. Kanatani, N. Kanda, N. Kanematsu, J. Kanzaki, R. Kikuchi, T. Kondo, T. T. Korhonen, A. E. Krüger, H. Kurashige, J. MacNaughton, T. Matsui, K. Miyake, M. Miura, S. Mori, Y. Nagashima, T. Nakamura, I. Nakano, S. Odaka, K. Ogawa, T. Ohama, T. Ohsugi, H. Ohyama, A. Okamoto, A. Ono, T. Oyama, H. Sakamoto, M. Sakuda, M. Sato, N. Sato, M. Shioden, J. Shirai, M. Shirakata, T. Sumiyoshi, A. Suzuki, Y. Takada, F. Takasaki, M. Takita, N. Tamura, K. Tobimatsu, T. Tsuboyama, S. Uehara, Y. Unno, M. Utsumi, Y. Watase, F. Yabuki, Y. Yamada, T. Yamagata, Y. Yonezawa, H. Yoshida, Physical Review Letters, Physical Review Letters, 71(1), 38 - 41, 1993 , Refereed
    Summary:Inclusive momentum spectra of charged particles in three-fold symmetric three-jet (qqg) and two-jet +(qq) events taken from e+e- annihilation at center-of-mass energy of 58 GeV were compared. The spectrum of gluon jets was found to be significantly softer than that of quark jets with the same energy and topology. © 1993 The American Physical Society.
  • Measurement of forward-backward charge asymmetry in the process of b-quark production in e+e- annihilation around √s=60 GeV, M. Shirakata, M. Utsumi, K. Abe, K. Amako, Y. Arai, Y. Asano, M. Chiba, Y. Chiba, M. Daigo, M. Fukawa, T. Fukui, Y. Fukushima, J. Haba, Y. Hemmi, M. Higuchi, F. Hinode, T. Hirose, Y. Homma, Y. Hoshi, N. Ishihara, N. Kanda, N. Kanematsu, J. Kanzaki, R. Kikuchi, T. T. Korhonen, T. Kondo, T. Koseki, H. Kurashige, J. MacNaughton, T. Matsui, M. Minami, K. Miyake, S. Mori, Y. Nagashima, T. Nakamura, I. Nakano, Y. Narita, S. Odaka, K. Ogawa, T. Ohama, T. Ohsugi, A. Okamoto, A. Ono, T. Oyama, H. Sakamoto, M. Sakuda, N. Sasao, M. Sato, H. Shibuya, M. Shioden, J. Shirai, S. Sugimoto, T. Sumiyoshi, A. Suzuki, Y. Takada, H. Takaki, F. Takasaki, A. Taketani, M. Takita, N. Tamura, N. Terunuma, K. Tobimatsu, T. Tsuboyama, S. Uehara, Y. Unno, T. Watanabe, Y. Watase, F. Yabuki, Y. Yamada, Y. Yonezawa, H. Yoshida, Physics Letters B, Physics Letters B, 278(4), 499 - 505, Apr. 02 1992 , Refereed
    Summary:We have measured the forward-backward charge asymmetry in the process of b-quark production in e+e- annihilation at TRISTAN. It was made possible by detecting prompt leptons from b-quarks. The obtained asymmetry is A= -0.55±0.15±0.08. If corrected for B-meson mixing effects with the assumptions given in the text, the asymmetry becomes A=f-0.78±0.21±0.11, which is consistent with the prediction of the standard model, namely the assignment of the b-quark to the isospin doublet of the third quark generation. © 1992.
  • MEASUREMENT OF THE FORWARD BACKWARD ASYMMETRY OF CHARM QUARK PRODUCTION IN E+E- ANNIHILATIONS AT (ROOT-S) = 58.4 GEV, A OKAMOTO, K ABE, K AMAKO, Y ARAI, Y ASANO, M CHIBA, Y CHIBA, M DAIGO, M FUKAWA, T FUKUI, Y FUKUSHIMA, J HABA, Y HEMMI, M HIGUCHI, F HINODE, T HIROSE, Y HOJO, Y HOMMA, Y HOSHI, N ISHIHARA, T KAMITANI, N KANEMATSU, N KANDA, J KANZAKI, R KIKUCHI, T KONDO, TT KORHONEN, T KOSEKI, H KURASHIGE, J MACNAUGHTON, T MATSUI, M MINAMI, K MIYAKE, S MORI, Y NAGASHIMA, T NAKAMURA, NAKANO, I, Y NARITA, S ODAKA, K OGAWA, T OHAMA, T OHSUGI, A ONO, T OYAMA, H SAKAMOTO, M SAKUDA, N SASAO, M SATO, N SATO, H SHIBUYA, M SHIODEN, J SHIRAI, S SHIRAKATA, S SUGIMOTO, T SUMIYOSHI, A SUZUKI, Y TAKADA, H TAKAKI, F TAKASAKI, A TAKETANI, M TAKITA, N TAMURA, N TERUNUMA, K TOBIMATSU, T TSUBOYAMA, S UEHARA, Y UNNO, M UTSUMI, T WATANABE, Y WATASE, F YABUKI, Y YAMADA, Y YONEZAWA, H YOSHIDA, PHYSICS LETTERS B, PHYSICS LETTERS B, 278(3), 393 - 398, Mar. 1992 , Refereed
    Summary:The forward-backward asymmetry of charm quark production has been measured at an average energy of 58.4 GeV with the VENUS detector at the TRISTAN e+e- collider. The charm quarks were identified through reconstruction of charged D* mesons using the mass difference between the D* and D0 mesons. The measured charge asymmetry, -0.49(-0.17)+0.19 +/- 0.04, is consistent with the prediction of the standard theory. The corresponding axial-vector coupling constant is 1.03(-0.35)+0.40 +/- 0.07.
  • Search for χc2 production in two-photon processes, S. Uehara, K. Abe, K. Amako, Y. Arai, Y. Asano, M. Chiba, Y. Chiba, M. Daigo, M. Fukuwa, T. Fukui, Y. Fukushima, J. Haba, Y. Hemmi, M. Higuchi, F. Hinode, T. Hirose, Y. Hojyo, Y. Homma, Y. Hoshi, N. Ishihara, T. Kamitani, N. Kanematsu, N. Kanda, J. Kanzaki, R. Kikuchi, T. Kondo, T. T. Korhonen, T. Koseki, H. Kurashige, T. Matsui, M. Minami, K. Miyake, S. Mori, Y. Nagashima, T. Nakamura, I. Nakano, Y. Narita, S. Odaka, K. Ogawa, T. Ohama, T. Ohsugi, A. Okamoto, A. Ono, T. Oyama, H. Sakamoto, M. Sakuda, N. Sasao, M. Sato, H. Shibuya, M. Shioden, J. Shirai, M. Shirakata, S. Sugimoto, T. Sumiyoshi, A. Suzuki, Y. Takada, H. Takaki, F. Takasaki, A. Taketani, M. Takita, N. Tamura, N. Terunuma, K. Tobimatsu, T. Tsuboyama, Y. Unno, M. Utsumi, T. Watanabe, Y. Watase, F. Yabuki, Y. Yamada, Y. Yonezawa, H. Yoshida, Physics Letters B, Physics Letters B, 266(1-2), 188 - 192, Aug. 22 1991 , Refereed
    Summary:A search has been made for the production of a charmonium state χc2 in two-photon processes. We have used the decay channel χc2→γJ/ψ, J/ψ→ℓ+ℓ-. No signal enhancement indicating the production of χc2 has been observed in the invariant mass distributions of the final state particles, and an upper limit for the two-photon decay width, Γγγ(χc2)< 4.2 keV at 95% CL, has been obtained. © 1991.
  • Study of the e+e- → μ+μ-γ reaction at center-of-mass energies between 54 and 64 GeV, Y. Yonezawa, K. Abe, K. Amako, Y. Arai, Y. Asano, M. Chiba, Y. China, M. Daigo, M. Fukawa, T. Fukui, Y. Fukushima, J. Haba, Y. Hemmi, M. Higuchi, F. Hinode, T. Hirose, Y. Hojyo, Y. Homma, Y. Hoshi, N. Ishihara, T. Kamitani, N. Kanematsu, N. Kanda, J. Kanzaki, R. Kikuchi, T. Kondo, T. T. Korhonen, T. Kosemi, H. Kurashige, T. Matsui, M. Minami, K. Miyake, S. Mori, Y. Nagashima, T. Nakamura, I. Nakano, Y. Narita, S. Odaka, K. Ogawa, T. Ohama, T. Ohsugi, A. Okamoto, A. Ono, T. Oyama, H. Sakamoto, M. Sakuda, N. Sasao, M. Sato, H. Shibuya, M. Shioden, J. Shirai, M. Shirakata, S. Sugimoto, T. Sumiyoshi, A. Suzuki, Y. Takada, H. Takaki, F. Takasaki, A. Taketani, M. Takita, N. Tamura, N. Terunuma, K. Tobimatsu, T. Tsuboyama, S. Uehara, Y. Unno, M. Utsumi, T. Watanabe, Y. Watase, F. Yabuki, Y. Yamada, H. Yoshida, Physics Letters B, Physics Letters B, 264(1-2), 212 - 218, Jul. 25 1991 , Refereed
    Summary:The cross section and forward-backward muon charge asymmetry for the e+e-→μ+μ-γ reaction were measured to be σ=2.82±0.35 pb and A=-0.34±0.10 with the VENUS detector at TRISTAN at 〈√s〉=59.2GeV for an integrated luminosity of 53.5 pb-1. The measured cross section agrees with the theoretical prediction. The asymmetry result is consistent with the electroweak prediction but not with the QED prediction at the level of 2σ. © 1991.
  • EXPERIMENTAL LIMITS ON EXTRA-Z BOSONS FROM E+E- ANNIHILATION DATA WITH THE VENUS DETECTOR AT SQUARE-ROOT-S=50-64 GEV, K ABE, K AMAKO, Y ARAI, Y ASANO, M CHIBA, Y CHIBA, M DAIGO, T EMURA, ENDO, I, M FUKAWA, T FUKUI, Y FUKUSHIMA, J HABA, HAYASHIBARA, I, Y HEMMI, M HIGUCHI, T HIROSE, Y HOJYO, Y HOMMA, Y HOSHI, Y IKEGAMI, N ISHIHARA, T KAMITANI, N KANEMATSU, J KANZAKI, R KIKUCHI, T KONDO, T KOSEKI, K KUBO, H KURASHIGE, T MATSUI, M MINAMI, K MIYAKE, S MORI, Y NAGASHIMA, T NAKAMURA, NAKANO, I, Y NARITA, S ODAKA, K OGAWA, T OHAMA, T OHSUGI, A OKAMOTO, A ONO, H OSABE, T OYAMA, H SAITO, H SAKAE, H SAKAMOTO, S SAKAMOTO, M SAKANO, M SAKUDA, N SASAO, M SATO, M SHIODEN, J SHIRAI, M SHIRAKATA, F SUEKANE, S SUGIMOTO, T SUMIYOSHI, A SUZUKI, Y SUZUKI, Y TAKADA, F TAKASAKI, A TAKETANI, M TAKITA, N TAMURA, R TANAKA, N TERUNUMA, K TOBIMATSU, T TSUBOYAMA, A TSUKAMOTO, S UEHARA, Y UNNO, M UTSUMI, M WAKAI, T WATANABE, Y WATASE, F YABUKI, Y YAMADA, T YAMAGATA, T YAMASHITA, Y YONEZAWA, H YOSHIDA, PHYSICS LETTERS B, PHYSICS LETTERS B, 246(1-2), 297 - 305, Aug. 1990 , Refereed
  • Search for SUSY-Partners of Charged Leptons in e+e- Collisions with √s up to 60.8 GeV., Yasushige Yonezawa, Phys. Lett. B, Phys. Lett. B, 234, 202, May 1990 , Refereed
  • DETERMINATION OF THE QCD SCALE PARAMETER LAMBDA-MSBAR WITH QCD CASCADE ON THE BASIS OF THE NEXT-TO-LEADING LOGARITHMIC APPROXIMATION, K ABE, K AMAKO, Y ARAI, Y ASANO, M CHIBA, Y CHIBA, M DAIGO, T EMURA, M FUKAWA, T FUKUI, Y FUKUSHIMA, J HABA, D HAIDT, HAYASHIBARA, I, Y HEMMI, M HIGUCHI, T HIROSE, Y HOJO, Y HOMMA, Y HOSHI, Y IKEGAMI, N ISHIHARA, T KAMITANI, N KANEMATSU, J KANZAKI, R KIKUCHI, T KONDO, T KOSEKI, H KURASHIGE, T MATSUI, M MINAMI, K MIYAKE, S MORI, Y NAGASHIMA, T NAKAMURA, NAKANO, I, Y NARITA, S ODAKA, K OGAWA, T OHAMA, T OHSUGI, A OKAMOTO, A ONO, H OSABE, T OYAMA, H SAITO, H SAKAE, H SAKAMOTO, S SAKAMOTO, M SAKANO, M SAKUDA, N SASAO, M SATO, M SHIODEN, J SHIRAI, M SHIRAKATA, S SUGIMOTO, T SUMIYOSHI, A SUZUKI, Y SUZUKI, Y TAKADA, F TAKASAKI, A TAKETANI, M TAKITA, N TAMURA, R TANAKA, N TERUNUMA, K TOBIMATSU, T TSUBOYAMA, A TSUKAMOTO, S UEHARA, Y UNNO, M UTSUMI, M WAKAI, T WATANABE, Y WATASE, F YABUKI, Y YAMADA, T YAMAGATA, T YAMASHITA, Y YONEZAWA, H YOSHIDA, PHYSICS LETTERS B, PHYSICS LETTERS B, 240(1-2), 232 - 236, Apr. 1990 , Refereed
  • MEASUREMENT OF THE REACTIONS E+E--]MU+MU- AND E+E--]TAU+TAU- BETWEEN SQUARE-ROOT-S = 50 AND 60.8 GEV, K ABE, K AMAKO, Y ARAI, Y ASANO, M CHIBA, Y CHIBA, M DAIGO, T EMURA, ENDO, I, M FUKAWA, T FUKUI, Y FUKUSHIMA, J HABA, D HAIDT, HAYASHIBARA, I, Y HEMMI, M HIGUCHI, T HIROSE, Y HOJYO, Y HOMMA, Y HOSHI, Y IKEGAMI, N ISHIHARA, T KAMITANI, N KANEMATSU, J KANZAKI, R KIKUCHI, T KONDO, T KOSEKI, K KUBO, H KURASHIGE, T MATSUI, M MINAMI, K MIYAKE, S MORI, Y NAGASHIMA, T NAKAMURA, NAKANO, I, Y NARITA, S ODAKA, K OGAWA, T OHAMA, T OHSUGI, A OKAMOTO, A ONO, H OSABE, T OYAMA, H SAITO, H SAKAE, H SAKAMOTO, S SAKAMOTO, M SAKANO, M SAKUDA, N SASAO, M SATO, M SHIODEN, J SHIRAI, F SUEKANE, S SUGIMOTO, T SUMIYOSHI, Y SUZUKI, Y TAKADA, F TAKASAKI, A TAKETANI, N TAMURA, R TANAKA, N TERUNUMA, K TOBIMATSU, T TSUBOYAMA, A TSUKAMOTO, S UEHARA, Y UNNO, M UTSUMI, M WAKAI, T WATANABE, Y WATASE, Y YAMADA, T YAMAGATA, T YAMASHITA, Y YONEZAWA, H YOSHIDA, ZEITSCHRIFT FUR PHYSIK C-PARTICLES AND FIELDS, ZEITSCHRIFT FUR PHYSIK C-PARTICLES AND FIELDS, 48(1), 13 - 21, 1990 , Refereed
  • A STUDY ON SINGLE PHOTON PRODUCTION AT SQUARE-ROOT-S =54.0-61.4 GEV, K ABE, K AMAKO, Y ARAI, Y ASANO, M CHIBA, Y CHIBA, M DAIGO, T EMURA, ENDO, I, M FUKAWA, T FUKUI, Y FUKUSHIMA, J HABA, D HAIDT, HAYASHIBARA, I, Y HEMMI, M HIGUCHI, T HIROSE, Y HOJYO, Y HOMMA, Y HOSHI, Y IKEGAMI, N ISHIHARA, T KAMITANI, N KANEMATSU, J KANZAKI, R KIKUCHI, T KONDO, T KOSEKI, H KURASHIGE, T MATSUI, M MINAMI, K MIYAKE, S MORI, Y NAGASHIMA, T NAKAMURA, NAKANO, I, Y NARITA, S ODAKA, K OGAWA, T OHAMA, T OHSUGI, A OKAMOTO, A ONO, H OSABE, T OYAMA, H SAITO, H SAKAE, H SAKAMOTO, S SAKAMOTO, M SAKANO, M SAKUDA, N SASAO, M SATO, M SHIODEN, J SHIRAI, S SHIRAKATA, S SUGIMOTO, T SUMIYOSHI, S SUZUKI, Y SUZUKI, Y TAKADA, F TAKASAKI, A TAKETANI, M TAKITA, N TAMURA, R TANAKA, N TERUNUMA, K TOBIMATSU, T TSUBOYAMA, A TSUKAMOTO, S UEHARA, Y UNNO, M UTSUMI, M WAKAI, T WATANABE, Y WATASE, F YABUKI, Y YAMADA, T YAMAGATA, T YAMASHITA, Y YONEZAWA, H YOSHIDA, PHYSICS LETTERS B, PHYSICS LETTERS B, 232(3), 431 - 436, Dec. 1989 , Refereed
  • CHARGE ASYMMETRY OF HADRON JETS AND LIMITS ON THE COMPOSITENESS SCALES IN THE EPSILON+EPSILON--]QBARQ REACTION AT LESS-THAN SQUARE-ROOT-S GREATER-THAN =57.6 GEV, K ABE, K AMAKO, Y ARAI, Y ASANO, M CHIBA, Y CHIBA, M DAIGO, T EMURA, ENDO, I, M FUKAWA, T FUKUI, Y FUKUSHIMA, J HABA, D HAIDT, HAYASHIBARA, I, Y HEMMI, M HIGUCHI, T HIROSE, Y HOJYO, Y HOMMA, Y HOSHI, Y IKEGAMI, N ISHIHARA, T KAMITANI, N KANEMATSU, J KANZAKI, R KIKUCHI, T KONDO, T KOSEKI, K KUBO, H KURASHIGE, T MATSUI, M MINAMI, K MIYAKE, S MORI, Y NAGASHIMA, T NAKAMURA, NAKANO, I, Y NARITA, S ODAKA, K OGAWA, T OHAMA, T OHSUGI, A OKAMOTO, A ONO, H OSABE, T OYAMA, H SAITO, H SAKAE, H SAKAMOTO, S SAKAMOTO, M SAKANO, M SAKUDA, N SASAO, M SATO, M SHIODEN, J SHIRAI, S SHIRAKATA, F SUEKANE, S SUGIMOTO, T SUMIYOSHI, S SUZUKI, Y SUZUKI, Y TAKADA, F TAKASAKI, A TAKETANI, M TAKITA, N TAMURA, R TANAKA, N TERUNUMA, K TOBIMATSU, T TSUBOYAMA, A TSUKAMOTO, S UEHARA, Y UNNO, M UTSUMI, M WAKAI, T WATANABE, Y WATASE, F YABUKI, Y YAMADA, T YAMAGATA, T YAMASHITA, Y YONEZAWA, H YOSHIDA, PHYSICS LETTERS B, PHYSICS LETTERS B, 232(3), 425 - 430, Dec. 1989 , Refereed
  • Search for a fourth-generation quark with -Q-=e/3 in e+e- collisions at s =56"57 GeV, K. Abe, K. Amako, Y. Arai, Y. Asano, M. Chiba, Y. Chiba, M. Daigo, T. Emura, I. Endo, M. Fukawa, T. Fukui, Y. Fukushima, J. Haba, D. Haidt, I. Hayashibara, Y. Hemmi, M. Higuchi, T. Hirose, Y. Hojyo, Y. Homma, Y. Hoshi, Y. Ikegami, N. Ishihara, T. Kamitani, N. Kanematsu, J. Kanzaki, R. Kikuchi, T. Kondo, T. Koseki, H. Kurashige, T. Matsui, M. Minami, K. Miyake, S. Mori, Y. Nagashima, T. Nakamura, I. Nakano, Y. Narita, S. Odaka, K. Ogawa, T. Ohama, T. Ohsugi, A. Okamoto, A. Ono, H. Osabe, T. Oyama, H. Saito, H. Sakae, H. Sakamoto, S. Sakamoto, M. Sakano, M. Sakuda, N. Sasao, M. Sato, M. Shioden, J. Shirai, S. Sugimoto, T. Sumiyoshi, Y. Suzuki, Y. Takada, F. Takasaki, A. Taketani, N. Tamura, R. Tanaka, N. Terunuma, K. Tobimatsu, T. Tsuboyama, A. Tsukamoto, S. Uehara, Y. Unno, M. Utsumi, M. Wakai, T. Watanabe, Y. Watase, Y. Yamada, T. Yamagata, T. Yamashita, Y. Yonezawa, H. Yoshida, Physical Review D, Physical Review D, 39(11), 3524 - 3527, 1989 , Refereed
    Summary:A search for a fourth-generation quark with -Q-=e/3 has been made with the VENUS detector at the KEK e+e- collider TRISTAN. Multihadron events with a spherical shape or containing isolated leptons were studied. There is no evidence for an excess production of such events in e+e- collision at s =56"57 GeV and a lower limit on the mass is 27.5 GeV/c2 at the 95% C.L. © 1989 The American Physical Society.
  • MEASUREMENT OF THE DIFFERENTIAL CROSS-SECTIONS OF E+E--]GAMMA-GAMMA AND E+E--]GAMMA-GAMMA-GAMMA AT SQUARE-ROOT-S=55, 56, 56.5 AND 57-GEV AND SEARCH FOR UNSTABLE PHOTINO PAIR PRODUCTION, K ABE, K AMAKO, Y ARAI, M FUKAWA, Y FUKUSHIMA, N ISHIHARA, D HAIDT, J KANZAKI, T KONDO, T MATSUI, S ODAKA, K OGAWA, T OHAMA, H SAKAMOTO, J SHIRAI, T SUMIYOSHI, F TAKASAKI, T TSUBOYAMA, S UEHARA, Y UNNO, Y WATASE, Y YAMADA, Y ASANO, T KOSEKI, S MORI, M SAKANO, Y TAKADA, Y YONEZAWA, M CHIBA, T FUKUI, T HIROSE, Y NARITA, T OYAMA, M UTSUMI, M MINAMI, H SAITO, M WAKAI, T WATANABE, T YAMAGATA, Y CHIBA, ENDO, I, HAYASHIBARA, I, T OHSUGI, A TAKETANI, R TANAKA, N TERUNUMA, M DAIGO, T EMURA, J HABA, T KAMITANI, N KANEMATSU, Y NAGASHIMA, H OSABE, S SAKAMOTO, S SUGIMOTO, Y SUZUKI, A TSUKAMOTO, T YAMASHITA, Y HEMMI, R KIKUCHI, H KURASHIGE, K MIYAKE, A OKAMOTO, N SASAO, N TAMURA, M HIGUCHI, Y HOSHI, M SATO, Y HOJYO, H SAKAE, Y HOMMA, Y IKEGAMI, NAKANO, I, A ONO, T NAKAMURA, M SHIODEN, K TOBIMATSU, H YOSHIDA, ZEITSCHRIFT FUR PHYSIK C-PARTICLES AND FIELDS, ZEITSCHRIFT FUR PHYSIK C-PARTICLES AND FIELDS, 45(2), 175 - 191, 1989 , Refereed
  • Atomistic Detailed Free-energy Landscape of Intrinsically Disordered Protein studied by Multi-scale Divide-and-conquer Molecular Dynamics Simulation, M. Shimoyama, Y. yonezawa, Journal of Computational Chemistry (accepted), Journal of Computational Chemistry (accepted), Sep. 2020 , Refereed
  • Epigenetic Protection of Vertebrate Lymphoid Progenitor Cells by Dnmt1, Norimasa Iwanami, Kohei Takeshita, Divine-Fondzenyuy Lawi, IsaoSuetake, ShojiTajima, KatarzynaSikora, InêsTrancoso, ConnorÓMeara, IlianaSiamishi, YousukeTakahama, MakotoFurutani, Seiki, HisatoKondoh, YasushigeYonezawa, MichaelSchorpp, ThomasBoehm, iScience, iScience, 23(7), Jun. 2020 , Refereed
  • On-the-fly analysis of molecular dynamics simulation trajectories of proteins using the Bayesian inference method, Naoyuki Miyashita, Yasushige Yonezawa, JOURNAL OF CHEMICAL PHYSICS, JOURNAL OF CHEMICAL PHYSICS, 147(12), 124108, Sep. 2017 , Refereed
    Summary:Robust and reliable analyses of long trajectories from molecular dynamics simulations are important for investigations of functions and mechanisms of proteins. Structural fitting is necessary for various analyses of protein dynamics, thus removing time-dependent translational and rotational movements. However, the fitting is often difficult for highly flexible molecules. Thus, to address the issues, we proposed a fitting algorithm that uses the Bayesian inference method in combination with rotational fitting-weight improvements, and the well-studied globular protein systems trpcage and lysozyme were used for investigations. The present method clearly identified rigid core regions that fluctuate less than other regions and also separated core regions from highly fluctuating regions with greater accuracy than conventional methods. Our method also provided simultaneous variance-covariance matrix elements composed of atomic coordinates, allowing us to perform principle component analysis and prepare domain cross-correlation map during molecular dynamics simulations in an on-the-fly manner. Published by AIP Publishing.
  • Free Energy Reconstruction from Logarithmic Mean-Force Dynamics Using Multiple Nonequilibrium Trajectories, T. Morishita, Y. Yonezawa, A. M. Ito, 13(7), 3106 - 3119, Jun. 2017 , Refereed
  • A Method for Predicting Protein Conformational Pathways by Using Molecular Dynamics Simulations Guided by Difference Distance Matrices, Yasushige Yonezawa, JOURNAL OF COMPUTATIONAL CHEMISTRY, JOURNAL OF COMPUTATIONAL CHEMISTRY, 37(13), 1139 - 1146, Mar. 2016 , Refereed
    Summary:Here, an efficient method that predicts natural transition pathways between two endpoint states of an allosteric protein has been proposed. This method helps create structures that bridge these endpoints through multiple iterative and unbiased molecular dynamics simulations with explicit water. Difference distance matrices provide an approach for identifying states involving concerted slow motion. A series of structures are readily generated along the transition pathways of adenylate kinase. Predicted structures may be useful for an initial pathway to evaluate free energy landscapes via umbrella sampling and chain-of-states methods. (C) 2016 Wiley Periodicals, Inc.
  • Direct Interaction between the Voltage Sensors Produces Cooperative Sustained Deactivation in Voltage-gated H+ Channel Dimers, Hiroko Okuda, Yasushige Yonezawa, Yu Takano, Yasushi Okamura, Yuichiro Fujiwara, JOURNAL OF BIOLOGICAL CHEMISTRY, JOURNAL OF BIOLOGICAL CHEMISTRY, 291(11), 5935 - 5947, Mar. 2016 , Refereed
    Summary:The voltage-gated H+ channel (Hv) is a voltage sensor domain-like protein consisting of four transmembrane segments (S1-S4). The native Hv structure is a homodimer, with the two channel subunits functioning cooperatively. Here we show that the two voltage sensor S4 helices within the dimer directly cooperate via a -stacking interaction between Trp residues at the middle of each segment. Scanning mutagenesis showed that Trp situated around the original position provides the slow gating kinetics characteristic of the dimer's cooperativity. Analyses of the Trp mutation on the dimeric and monomeric channel backgrounds and analyses with tandem channel constructs suggested that the two Trp residues within the dimer are functionally coupled during Hv deactivation but are less so during activation. Molecular dynamics simulation also showed direct -stacking of the two Trp residues. These results provide new insight into the cooperative function of voltage-gated channels, where adjacent voltage sensor helices make direct physical contact and work as a single unit according to the gating process.
  • Development of massive multilevel molecular dynamics simulation program, platypus (PLATform for dYnamic protein unified simulation), for the elucidation of protein functions, Yu Takano, Kazuto Nakata, Yasushige Yonezawa, Haruki Nakamura, JOURNAL OF COMPUTATIONAL CHEMISTRY, JOURNAL OF COMPUTATIONAL CHEMISTRY, 37(12), 1125 - 1132, 2016 , Refereed
    Summary:A massively parallel program for quantum mechanical-molecular mechanical (QM/MM) molecular dynamics simulation, called Platypus (PLATform for dYnamic Protein Unified Simulation), was developed to elucidate protein functions. The speedup and the parallelization ratio of Platypus in the QM and QM/MM calculations were assessed for a bacteriochlorophyll dimer in the photosynthetic reaction center (DIMER) on the K computer, a massively parallel computer achieving 10 PetaFLOPs with 705,024 cores. Platypus exhibited the increase in speedup up to 20,000 core processors at the HF/cc-pVDZ and B3LYP/cc-pVDZ, and up to 10,000 core processors by the CASCI(16,16)/6-31G** calculations. We also performed excited QM/MM-MD simulations on the chromophore of Sirius (SIRIUS) in water. Sirius is a pH-insensitive and photo-stable ultramarine fluorescent protein. Platypus accelerated on-the-fly excited-state QM/MM-MD simulations for SIRIUS in water, using over 4000 core processors. In addition, it also succeeded in 50-ps (200,000-step) on-the-fly excited-state QM/MM-MD simulations for the SIRIUS in water. (c) 2016 The Authors. Journal of Computational Chemistry Published by Wiley Periodicals, Inc.
  • Molecular Dynamics Study of the Phosphorylation Effect on the Conformational States of the C-Terminal Domain of RNA Polymerase II, Yasushige Yonezawa, JOURNAL OF PHYSICAL CHEMISTRY B, JOURNAL OF PHYSICAL CHEMISTRY B, 118(17), 4471 - 4478, May 2014 , Refereed
    Summary:The carboxyl-terminal domain (CTD) of RNA polymerase II in eukaryotes regulates mRNA processing processes by recruiting various regulation factors. A main function of the CTD relies on the heptad consensus sequence (YSPTSPS). The CTD dynamically changes its conformational state to recognize and bind different regulation factors. The dynamical conformation changes are caused by modifications, mainly phosphorylation and dephosphorylation, to the serine residues. In this study, we investigate the conformational states of the unit consensus CTD peptide with various phosphorylation patterns of the serine residues by extended ensemble simulations. The results show that the CTD without phosphorylation has a flexible disordered structure distributed between twisted and extended states, but phosphorylation tends to reduce the conformational space. It was found that phosphorylation induces a beta-turn around the phosphorylated serine residue and the cis conformation of the proline residue significantly inhibits the beta-turn formation. The beta-turn should contribute to specific CTD binding of the different regulation factors by changing the conformation propensity combined with induced fit.
  • Electrostatic properties of water models evaluated by a long-range potential based solely on the Wolf charge-neutral condition, Yasushige Yonezawa, CHEMICAL PHYSICS LETTERS, CHEMICAL PHYSICS LETTERS, 556, 308 - 314, Jan. 2013 , Refereed
    Summary:In this Letter, we evaluate the electrostatic properties of several biologically important waters that have been coupled to general force fields and are used in biological applications, namely SPC/E, TIP4P, TIP4P-Ewald, and TIP4P/2005, with a recently developed long-range Coulomb potential based solely on the Wolf charge-neutral principle. The potential was shown previously to accurately reproduce several important electrostatic properties of biological systems. Moreover, it enables scalable computation, yielding faster calculations. The present results demonstrate that the calculated electrostatic properties of the water models based on the long-range potential agree well with those calculated by the particle mesh Ewald method. (C) 2012 Elsevier B. V. All rights reserved.
  • Simple and accurate scheme to compute electrostatic interaction: Zero-dipole summation technique for molecular system and application to bulk water, Ikuo Fukuda, Narutoshi Kamiya, Yasushige Yonezawa, Haruki Nakamura, JOURNAL OF CHEMICAL PHYSICS, JOURNAL OF CHEMICAL PHYSICS, 137(5), 054314, Aug. 2012 , Refereed
    Summary:The zero-dipole summation method was extended to general molecular systems, and then applied to molecular dynamics simulations of an isotropic water system. In our previous paper [I. Fukuda, Y. Yonezawa, and H. Nakamura, J. Chem. Phys. 134, 164107 (2011)], for evaluating the electrostatic energy of a classical particle system, we proposed the zero-dipole summation method, which conceptually prevents the nonzero-charge and nonzero-dipole states artificially generated by a simple cutoff truncation. Here, we consider the application of this scheme to molecular systems, as well as some fundamental aspects of general cutoff truncation protocols. Introducing an idea to harmonize the bonding interactions and the electrostatic interactions in the scheme, we develop a specific algorithm. As in the previous study, the resulting energy formula is represented by a simple pair-wise function sum, enabling facile applications to high-performance computation. The accuracy of the electrostatic energies calculated by the zero-dipole summation method with the atom-based cutoff was numerically investigated, by comparison with those generated by the Ewald method. We obtained an electrostatic energy error of less than 0.01% at a cutoff length longer than 13 angstrom for a TIP3P isotropic water system, and the errors were quite small, as compared to those obtained by conventional truncation methods. The static property and the stability in an MD simulation were also satisfactory. In addition, the dielectric constants and the distance-dependent Kirkwood factors were measured, and their coincidences with those calculated by the particle mesh Ewald method were confirmed, although such coincidences are not easily attained by truncation methods. We found that the zero damping-factor gave the best results in a practical cutoff distance region. In fact, in contrast to the zero-charge scheme, the damping effect was insensitive in the zero-charge and zero-dipole scheme, in the molecular system we treated. We discussed the origin of this difference between the two schemes and the dependence of this fact on the physical system. The use of the zero damping-factor will enhance the efficiency of practical computations, since the complementary error function is not employed. In addition, utilizing the zero damping-factor provides freedom from the parameter choice, which is not trivial in the zero-charge scheme, and eliminates the error function term, which corresponds to the time-consuming Fourier part under the periodic boundary conditions. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4739789]
  • A long-range electrostatic potential based on the Wolf method charge-neutral condition, Yasushige Yonezawa, JOURNAL OF CHEMICAL PHYSICS, JOURNAL OF CHEMICAL PHYSICS, 136(24), 244103, Jun. 2012 , Refereed
    Summary:Molecular simulations rely heavily on a long range electrostatic Coulomb interaction. The Coulomb potential decays inversely with distance, indicating infinite effective range. In practice, molecular simulations do not directly take into account such an infinite interaction. Therefore, the Ewald, fast multipole, and cutoff methods are frequently used. Although cutoff methods are implemented easily and the calculations are fast, it has been pointed out that they produce serious artifacts. Wolf and coworkers recently discovered one source of the artifacts. They found that when the total charge in a cutoff sphere disappeared, the cutoff error is dramatically suppressed. The Wolf method uses the charge-neutral principle combined with a potential damping that is realized using a complementary error function. To date, many molecular simulation studies have demonstrated the accuracy and reliability of the Wolf method. We propose a novel long-range potential that is constructed only from the charge-neutral condition of the Wolf method without potential damping. We also show that three simulation systems, in which involve liquid sodium-chloride, TIP3P water, and a charged protein in explicit waters with neutralized ions using the new potential, provide accurate statistical and dielectric properties when compared with the particle mesh Ewald method. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4729748]
  • Locality and Nonlocality of Electronic Structures of Molecular Systems: Toward QM/MM and QM/QM approaches, Shusuke Yamanaka, Yasushige Yonezawa, Kazuto Nakata, Satomichi Nishihara, Mitsutaka Okumura, Toshikazu Takada, Kizashi Yamaguchi, Haruki Nakamura, INTERNATIONAL CONFERENCE OF COMPUTATIONAL METHODS IN SCIENCES AND ENGINEERING 2009 (ICCMSE 2009), INTERNATIONAL CONFERENCE OF COMPUTATIONAL METHODS IN SCIENCES AND ENGINEERING 2009 (ICCMSE 2009), 1504, 916 - 919, 2012 , Refereed
    Summary:We present a simple guideline to inspect the large molecular systems towards QM/MM theory and various types of divide-and-conquer electronic structure theories, in which we utilize on the linear-response function. We present the basic ideas of our approach, simple introduction of the computational method, and some numerical results.
  • Free Energy Landscapes of Alanine Dipeptide in Explicit Water Reproduced by the Force-Switching Wolf Method, Yasushige Yonezawa, Ikuo Fukuda, Narutoshi Kamiya, Hiromitsu Shimoyama, Haruki Nakamura, JOURNAL OF CHEMICAL THEORY AND COMPUTATION, JOURNAL OF CHEMICAL THEORY AND COMPUTATION, 7(5), 1484 - 1493, May 2011
    Summary:Precise and rapid calculation of long-range interactions is of crucial importance for molecular dynamics (MD) and Monte Carlo simulations. Instead of the Ewald method or its high speed variant, PME, we applied our novel method, called the force-switching Wolf method, to computation of the free energy landscapes of a short peptide in explicit water. Wolf and co-workers showed that long-range electrostatic energy under a periodic boundary condition can be well reproduced even by truncating the. contribution from the distant charges, when the charge neutrality is taken into account. We recently applied the procedure proposed by Wolf and co-workers to a mathematically consistent MD theory by means of a force-switching scheme, and we show that the total electrostatic energy for sodium chloride liquid was well conserved and stable during the MD simulation with the force-switching Wolf method. Our current results for an aqueous peptide solution with a series of canonical and multicanonical molecular dynamics simulations show that the force-switching Wolf method is not only in good accordance with the energies and forces calculated by the conventional PME method but also properly reproduces the solvation and the free energy landscapes of the peptide at 300 K.
  • Theory for Trivial Trajectory Parallelization of Multicanonical Molecular Dynamics and Application to a Polypeptide in Water, Jinzen Ikebe, Koji Umezawa, Narutoshi Kamiya, Takanori Sugihara, Yasushige Yonezawa, Yu Takano, Haruki Nakamura, Junichi Higo, JOURNAL OF COMPUTATIONAL CHEMISTRY, JOURNAL OF COMPUTATIONAL CHEMISTRY, 32(7), 1286 - 1297, May 2011 , Refereed
    Summary:Trivial trajectory parallelization of multicanonical molecular dynamics (TTP-McMD) explores the conformational space of a biological system with multiple short runs of McMD starting from various initial structures. This method simply connects (i.e., trivially parallelizes) the short trajectories and generates a long trajectory. First, we theoretically prove that the simple trajectory connection satisfies a detailed balance automatically. Thus, the resultant long trajectory is regarded as a single multicanonical trajectory. Second, we applied TTP-McMD to an alanine decapeptide with an all-atom model in explicit water to compute a free-energy landscape. The theory imposes two requirements on the multiple trajectories. We have demonstrated that TTP-McMD naturally satisfies the requirements. The TTP-McMD produces the free-energy landscape considerably faster than a single-run McMD does. We quantitatively showed that the accuracy of the computed landscape increases with increasing the number of multiple runs. Generally, the free-energy landscape of a large biological system is unknown a priori. The current method is suitable for conformational sampling of such a large system to reduce the waiting time to obtain a canonical ensemble statistically reliable. (C) 2010 Wiley Periodicals, Inc. J Comput Chem 32: 1286-1297, 2011
  • Molecular dynamics scheme for precise estimation of electrostatic interaction via zero-dipole summation principle, Ikuo Fukuda, Yasushige Yonezawa, Haruki Nakamura, JOURNAL OF CHEMICAL PHYSICS, JOURNAL OF CHEMICAL PHYSICS, 134(16), 107, Apr. 2011 , Refereed
    Summary:We propose a novel idea, zero-dipole summation, for evaluating the electrostatic energy of a classical particle system, and have composed an algorithm for effectively utilizing the idea for molecular dynamics. It conceptually prevents the nonzero-charge and nonzero-dipole states artificially generated by a simple cutoff truncation. The resulting energy formula is nevertheless represented by a simple pairwise function sum, which enables facile application to high-performance computation. By following a heuristic approach to derive the current electrostatic energy formula, we developed an axiomatic approach to construct the method consistently. Explorations of the theoretical details of our method revealed the structure of the generated error, and we analyzed it by comparisons with other methods. A numerical simulation using liquid sodium chloride confirmed that the current method with a small damping factor yielded sufficient accuracy with a practical cutoff distance region. The current energy function also conducts stable numerical integration in a liquid MD simulation. Our method is an extension of the charge neutralized summation developed by Wolf et al. [J. Chem. Phys. 110, 8254 (1999)]. Furthermore, we found that the current method becomes a generalization of the preaveraged potential method proposed by Yakub and Ronchi [J. Chem. Phys. 119, 11556 (2003)], which is based on a viewpoint different from the neutrality. The current study presents these relationships and suggests possibilities for their further applications. c 2011 American Institute of Physics. [doi:10.1063/1.3582791]
  • Degree of pyramidality governs the height and peak position of the free-energy-barrier for the cis-trans isomerization of N-Methylacetamide, Yasushige Yonezawa, Daron M. Standley, Haruki Nakamura, CHEMICAL PHYSICS LETTERS, CHEMICAL PHYSICS LETTERS, 503(1-3), 139 - 144, Feb. 2011
    Summary:The cis-trans isomerization mechanism of N-Methylacetamide was studied by molecular dynamics simulations employing a hybrid QM/MM potential with explicit water. In combination with the umbrella sampling method, we obtained the free-energy barrier between the cis-trans states in accordance with previous experimental and theoretical values. Moreover, we found that the improper dihedral angle, C(=O)-N-H-C(-H3), correlates well with the degree of the pyramidal conformations. We then investigated the role of the degree of the pyramidal conformation with respect to the isomerization processes and found that it governs the height and peak position of the free-energy barriers and the hydration structure. (C) 2011 Elsevier B. V. All rights reserved.
  • Effective computational method for evaluation of dynamic elecrostatic effects of explicit solvent and membrane molecules from molecular dynamics simulations, Yasushige Yonezawa, Proceedings - 7th IEEE International Conference on e-Science Workshops, eScienceW 2011, Proceedings - 7th IEEE International Conference on e-Science Workshops, eScienceW 2011, 178 - 182, 2011 , Refereed
    Summary:Knowledge of the electronic structures of local functional sites of proteins sheds light into their fundamental mechanisms of enzymatic reaction and processes related to electronic state. Although the dynamic effects due to solvent or membrane molecules surrounding the protein are indispensable for an accurate analysis, in current methods they have been approximated by a continuum model with polarized material, where a phenomenological and unreliable parameter, the dielectric constant, is always required. We have developed a new algorithm to reproduce an average field due to the solvent and membrane molecules, which are calculated from the long trajectory of a classical molecular dynamics simulation for a membrane protein-solvent system, by several thousands of pseudo-charges and dipoles on a closed surface surrounding a target quantum mechanical (QM) region. Since the dynamic effects are represented only by "static" pseudo-charges and dipoles, the QM calculation is necessarily done only once. We applied this algorithm to the photosynthetic reaction center of Rhodobacter sphaeroides with explicit all-atomic models of the solvent and membrane molecules. It is possible that the electronic structures of its ground state and excited state can be calculated with those microscopic "reaction field" effects. © 2011 IEEE.
  • Multicanonical molecular dynamics simulations combined with Metadynamics for the free energy landscape of a biomolecular system with high energy barriers, Yasushige Yonezawa, Hiromitsu Shimoyama, Haruki Nakamura, CHEMICAL PHYSICS LETTERS, CHEMICAL PHYSICS LETTERS, 501(4-6), 598 - 602, Jan. 2011 , Refereed
    Summary:Multicanonical molecular-dynamics (McMD) simulation and Metadynamics (MetaD) are useful for obtaining the free-energies, and can be mutually complementary. We combined McMD with MetaD, and applied it to the conformational free energy calculations of a proline dipeptide. First, MetaD was performed along the dihedral angle at the prolyl bond and we obtained a coarse biasing potential. After adding the biasing potential to the dihedral angle potential energy, we conducted McMD with the modified potential energy. Enhanced sampling was achieved for all degrees-of-freedom, and the sampling of the dihedral angle space was facilitated. After reweighting, we obtained an accurate free energy landscape. (C) 2010 Elsevier B.V. All rights reserved.
  • Enhanced free-energy calculation using multiscale simulation, Hiromitsu Shimoyama, Yasushige Yonezawa, Haruki Nakamura, JOURNAL OF CHEMICAL PHYSICS, JOURNAL OF CHEMICAL PHYSICS, 133(13), 101, Oct. 2010 , Refereed
    Summary:We propose a multiscale simulation method combining the efficiency of a coarse-grained model (CGM) and the accuracy of an all-atom model (AAM) for free-energy landscape calculation of protein systems. A protein's conformation space is quickly searched first using CGM. Then the obtained information is incorporated into AAM simulations. The free-energy landscape is subsequently obtained from AAM simulations. This method was tested on chignolin folding. The results demonstrated that the computational time was reduced by as much as 90%. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3483898]
  • Resonating Coupled-Cluster CI Approach to Ion-Radical Systems: Comparison with the Unrestricted Coupled-Cluster Approach, S. Yamanaka, S. Nishihara, K. Nakata, Y. Yonezawa, M. Okumura, T. Takada, H. Nakamura, K. Yamaguchi, INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, 109(15), 3811 - 3818, Dec. 2009 , Refereed
    Summary:We implemented the resonating configuration interaction (Res-CI) approach with spin-unrestricted coupled-cluster (UCC) solutions as basis for ion-radical systems. In previous studies (Nishihara et al., Int J Quantum Chem 2008, 108, 2966; Nishihara et al., J Phys: Condens Matt 2009, 21, 064227), we showed that it is possible to satisfy an important condition proposed by Perdew et al. using Res-Cl based on two complementary spin-Unrestricted Hartree-Fock solutions. In this study, we extended the method to Res-Cl calculations based on UCC solutions (Res-CC Cl) for simple ion-radical systems, which is to our knowledge, a new type of ab initio method. We examined the asymmetric effects on whether the hole (or the excess electron) localizes at one site or delocalizes over two sites. The computational results of Res-CC Cl are compared with those of UCC, and the implications are discussed. (C) 2009 Wiley Periodicals, Inc. Int J Quantum Chem 109:3811-3818, 2009
  • Membrane Attachment Facilitates Ligand Access to the Active Site in Monoamine Oxidase A, Rossen Apostolov, Yasushige Yonezawa, Daron M. Standley, Gota Kikugawa, Yu Takano, Haruki Nakamura, BIOCHEMISTRY, BIOCHEMISTRY, 48(25), 5864 - 5873, Jun. 2009 , Refereed
    Summary:Monoamine oxidase membrane enzymes are responsible for the catalytic breakdown of extra-and intracellular neurotransmitters and are targets for the development of central nervous system drugs. We analyzed the dynamics of rat MAOA by performing multiple independent molecular dynamics simulations of membrane-bound and membrane-free forms to clarify the relationship between the mechanics of the enzyme and its function, with particular emphasis on the significance of membrane attachment. Principal component analysis of the simulation trajectories as well as correlations in the fluctuations of the residues pointed to the existence of three domains that define the global dynamics of the protein. Interdomain anticorrelated movements in the membrane-bound system facilitated the relaxation of interactions between residues surrounding the substrate cavity and induced conformational changes which expanded the active site cavity and opened putative pathways for substrate uptake and product release. Such events were less pronounced in the membrane-free system due to differences in the nature of the dominant modes of motion. The presence of the lipid environment is suggested to assist in decoupling the interdomain motions, consistent with the observed reduction in enzyme activity under membrane-free conditions. Our results are also in accordance with mutational analysis which shows that modifications of interdomain hinge residues decrease the activity of rat MAOA in solution.
  • A resonating broken-symmetry CI study of cationic states of phenalenyl dimeric compounds, S. Nishihara, S. Yamanaka, K. Nakata, Y. Kitagawa, Y. Yonezawa, M. Okumura, H. Nakamura, T. Takada, K. Yamaguchi, POLYHEDRON, POLYHEDRON, 28(9-10), 1628 - 1633, Jun. 2009 , Refereed
    Summary:We investigated several phenalenyl cationic dimer systems using ab initio methods. First, we examine the through-space cation dieter. The B3LYP method fails to describe the correct dissociation as in the case of usual cation dieters. On the other hand, the resonating broken symmetry configuration interaction (Res-BS CI) method based on unrestricted Hartree-Fock solutions yields the correct potential surface and correct charge distributions. Furthermore, we investigated though-bond interactions of the phenalenyl cationic dimer via acetylene and ethylene bridges. The results are considerably different from those of the though-space case, implying that these bridging units play important roles to determine charge and spin distributions. Judging from these results, different bridges-or-stacks lead to different hole behaviors, indicating the possibility of various electronic functionalities of hole-doped phenalenyl compounds. In particular, the acetylene bridge is expected to enhance the conductivity of the hole-doped phenalenyl compounds. (C) 2009 Elsevier Ltd. All rights reserved.
  • Intra- and Intermolecular Interaction Inducing Pyramidalization on Both Sides of a Proline Dipeptide during Isomerization: An Ab Initio QM/MM Molecular Dynamics Simulation Study in Explicit Water, Yasushige Yonezawa, Kazuto Nakata, Kota Sakakura, Toshikazu Takada, Haruki Nakamura, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 131(12), 4535 - 4540, Apr. 2009 , Refereed
    Summary:The cis-trans isomerization of the peptide bond preceding a proline plays important roles in protein folding and biological function. Although many experimental and theoretical studies have been done, the mechanism has not yet been clearly elucidated. We studied the cis-trans isomerization of the proline dipeptide (Ace-Pro-NMe) in explicit water by molecular dynamics simulations using a combined potential derived from ab initio quantum mechanics and empirical molecular mechanics. We obtained the free energy landscape during the isomerization by using the umbrella sampling method. The free energy landscape is in good accordance with previous experimental and theoretical values. We observed that in the middle of the isomerization, the prolyl nitrogen transiently takes pyramidal conformations in two polarized directions and that, simultaneously, the prolyl C-N bond extends. We show that these geometrical changes cooperatively transform the prolyl nitrogen from a sp(2)-hybridized electronic state into a sp(3)-hybridized one, and thus realize a transition state that reduces the rotational barriers separating the cis- and trans-states. We also found that the hydration of the prolyl nitrogen stabilizes the negative pyramidal conformation, while an intramolecular interaction mainly stabilizes the positive one. Fluctuations in the polarity and magnitude of the pyramidal conformation during the isomerization are interpreted as a competition between the hydrogen-bonding partners for the prolyl nitrogen between different sides of the pyrrolidine ring.
  • A resonating broken symmetry configuration interaction approach for double-exchange magnetic systems, S. Nishihara, S. Yamanaka, K. Kusakabe, K. Nakata, Y. Yonezawa, H. Nakamura, T. Takada, K. Yamaguchi, Journal of Physics Condensed Matter, Journal of Physics Condensed Matter, 21(6), 64227 - 64423, 2009 , Refereed
    Summary:The correct description for ion-radical systems has recently attracted much attention from density functional theory (DFT) researchers. Although several hybridization schemes using exact (Hartree-Fock) exchange and DFT exchange-correlation functionals have been proposed, it has been reported that such treatments do not work for the description of ion-radical systems. In this study we show that combining the exact exchange term in the Kohn-Sham DFT (or the Hartree-Fock equation) with the following resonating configuration interaction method is effective for the description of double-exchange type molecular magnetic interactions. The results are analyzed in relation to the 'many-electron self-interaction' concept that was recently proposed by DFT researchers. © 2009 IOP Publishing Ltd.
  • Application of MDGRAPE-3, a Special Purpose Board for Molecular Dynamics Simulations, to Periodic Biomolecular Systems, Gota Kikugawa, Rossen Apostolov, Narutoshi Kamiya, Makoto Taiji, Ryutaro Himeno, Haruki Nakamura, Yasushige Yonezawa, JOURNAL OF COMPUTATIONAL CHEMISTRY, JOURNAL OF COMPUTATIONAL CHEMISTRY, 30(1), 110 - 118, Jan. 2009 , Refereed
    Summary:We describe the application of a special purpose board for molecular dynamics simulations, named MDGRAPE-3, to the problem of simulating periodic bio-molecular systems. MDGRAPE-3 is the latest board in a series of hardware accelerators designed to calculate the nonbonding long-range interactions much more rapidly than normal processors. So far, MDGRAPEs were mainly applied to isolated systems, where very many nonbonded interactions were calculated without any distance cutoff. However, in order to regulate the density and pressure during simulations of membrane embedded protein systems, one has to evaluate interactions under periodic boundary conditions. For this purpose, we implemented the Particle-Mesh Ewald (PME) method, and its approximation with distance cutoffs and charge neutrality as proposed by Wolf et al., using MDGRAPE-3. When the two methods were applied to simulations of two periodic biomolecular systems, a single MDGRAPE-3 achieved 30-40 times faster computation times than a single conventional processor did in the both cases. Both methods are shown to have the same molecular structures and dynamics of the systems. (C) 2008 Wiley Periodicals, Inc. J Comput Chem 30: 110-118, 2009
  • Resonating Broken Symmetry CI Approach for Ion-Radical Systems: Comparison With UHF, Hybrid-DFT, and CASSCF-DFT, S. Nishihara, S. Yamanaka, T. Ukai, K. Nakata, K. Kusakabe, Y. Yonezawa, H. Nakamura, T. Takada, K. Yamaguchi, INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, 108(15), 2966 - 2977, Dec. 2008 , Refereed
    Summary:The resonating broken-symmetry configuration interaction (RBS-CI) approach, in which we employ two Spin-Unrestricted Hartree-Fock (UHF) solutions as the basis, is applied for the ion-radical systems. The RBS-CI results are compared with those of UHF, various hybrid density functional theory (DFT), and CASSCF-DFT. The hybrid DFT leads to the spurious delocalized state as is well known, whereas the UHF to the localized state. The CASSCF-DFT results show that the excess electron localized, missing the spatial symmetry of the systems. On the other hand, the Res-HF Cl results satisfy the spatial symmetry as well as the Perdew, Parr, Levy, and Balduz's relation implying that this method is so-called many-electron self-interaction free (ME-SIF), whereas all other method,; are not ME-SIF. These results suggest that the RBS-CI approach will become not only a powerful ab initio approach, but also a guideline to construct a new exchange-correlation functional of hybrid-DFT, for the ion-radical systems. (C) 2008 Wilev Periodicals, Inc. Int J Quantum Chem 108: 2960-2977, 2008
  • Consistent Molecular Dynamics Scheme Applying the Wolf Summation for Calculating Electrostatic Interaction of Particles, Ikuo Fukuda, Yasushige Yonezawa, Haruki Nakamura, JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, 77(11), 14301 - 14305, Nov. 2008
    Summary:We investigate the charge-neutralized summation method proposed by Wolf et al. for evaluating in a very simple manner the electrostatic interaction of a point particle system. We argue conceptional and problematic aspects encountered in the application of this method to molecular dynamics calculation. A novel molecular-dynarnics formulation for this method is then proposed and we describe how it resolves formal and practical difficulties in previous approaches. Theoretically consistent force. pairwise potential, and the total energy including it Suitable energy correction accompanied by a potential-function deformation are given. To clarify the new concept, the relationship between the char'le neutrality and the mirror-image charge expression is discussed.
  • A simple efficient molecular dynamics scheme for evaluating electrostatic interaction of particle, Ikuo Fukuda, Yasushige Yonezawa, Haruki Nakamura, COMPLEX SYSTEMS-BOOK 1, COMPLEX SYSTEMS-BOOK 1, 982, 792 - +, 2008 , Refereed
    Summary:We present results from a recently developed new molecular dynamics method to calculate electrostatic interaction of point particle systems. This method is very simple, which is based on the charge neutralized pairwise summation developed by Wolf et al., while solves problems presented in previous similar approaches and consistently gives the force, potential, and the total energy of the system.
  • Protein-inhibitor flexible docking by a multicanonical sampling: Native complex structure with the lowest free energy and a free-energy barrier distinguishing the native complex from the others, Narutoshi Kamiya, Yasushige Yonezawa, Haruki Nakamura, Junichi Higo, PROTEINS-STRUCTURE FUNCTION AND BIOINFORMATICS, PROTEINS-STRUCTURE FUNCTION AND BIOINFORMATICS, 70(1), 41 - 53, Jan. 2008 , Refereed
    Summary:Flexible docking between a protein (lysozyme) and an inhibitor (tri-N-acetyl-D-glucosamine, tri-NAG) was carried out by an enhanced conformational sampling method, multicanonical molecular dynamics simulation. We used a flexible all-atom model to express lysozyme, tri-NAG, and water molecules surrounding the two bio-molecules. The advantages of this sampling method are as follows: the conformation of system is widely sampled without trapping at energy minima, a thermally equilibrated conformational ensemble at an arbitrary temperature can be reconstructed from the simulation trajectory, and the thermodynamic weight can be assigned to each sampled conformation. During the simulation, exchanges between the binding and free (i.e., unbinding) states of the protein and the inhibitor were repeatedly observed. The conformational ensemble reconstructed at 300 K involved various conformational clusters. The main outcome of the current study is that the most populated conformational cluster (i.e., the cluster of the lowest free energy) was assigned to the native complex structure (i.e., the X-ray complex structure). The simulation also produced non-native complex structures, where the protein and the inhibitor bound with different modes from that of the native complex structure, as well as the unbinding structures. A free-energy barrier (i.e., activation free energy) was clearly detected between the native complex structures and the other structures. The thermal fluctuations of tri-NAG in the lowest free-energy complex correlated well with the X-ray B-factors of tri-NAG in the X-ray complex structure. The existence of the free-energy barrier ensures that the lowest free-energy structure can be discriminated naturally from the other structures. In other words, the multicanonical molecular dynamics simulation can predict the native complex structure without any empirical objective function. The current study also manifested that the flexible all-atom model and the physicochemically defined atomic-level force field can reproduce the native complex structure. A drawback of the current method is that it requires a time consuming computation due to the exhaustive conformational sampling. We discussed a possibility for combining the current method with conventional docking methods.
  • Effects of salt concentration on association of the amyloid protofilaments of hen egg white lysozyme studied by time-resolved neutron scattering, S Fujiwara, F Matsumoto, Y Yonezawa, JOURNAL OF MOLECULAR BIOLOGY, JOURNAL OF MOLECULAR BIOLOGY, 331(1), 21 - 28, Aug. 2003 , Refereed
    Summary:Various proteins have been shown to form various aggregated structures including the filamentous aggregates known as amyloid fibrils depending on the solution conditions. Hen egg white lysozyme (HEWL) is one of the proteins that form the amyloid fibrils. To gain insight into the mechanism of this polymorphism of the aggregated structures, we employed a model system consisting of HEWL, pure water, and ethanol, and investigated the kinetic process of the fibril formation in various salt concentrations with time-resolved neutron scattering. It was shown that by addition of NaCl in a range between 0.3 mM and 1.0 mM to HEWL solution in 90% ethanol, gelation occurred, and this gelation proceeded through a two-step process: the lateral association of the protofilaments, followed by the cross-linking of these fibrils formed. Both the structures of the fibrils and the rate of the gelation depended on NaCl concentration. The average structures of the fibrils formed at 1.0 mM NaCl were characterized by the radius of gyration of their cross-section (45.9(+/-0.4)Angstrom) and the number of the protofilaments within the fibril (4.10(+/-0.12)), corresponding to the mature amyloid fibrils. A range of intermediate structures was formed below 1 mM NaCl. Above 2 mM NaCl, precipitation occurred because of the formation of amorphous aggregates. Here the branch point to the formation of the mature amyloid fibrils or to the amorphous aggregates was after the formation of the protofilaments. Sensitivity of the aggregated structures to salt concentration suggests that electrostatic interaction plays an essential role in the formation of these structures. The structural diversity both in the fibrils and the aggregated structures of the fibrils can be interpreted in terms of the difference in the degree of the electrostatic shielding at different salt concentrations. (C) 2003 Elsevier Ltd. All rights reserved.
  • An insight into the pathway of the amyloid fibril formation of hen egg white lysozyme obtained from a small-angle X-ray and neutron scattering study, Y Yonezawa, S Tanaka, T Kubota, K Wakabayashi, K Yutani, S Fujiwara, JOURNAL OF MOLECULAR BIOLOGY, JOURNAL OF MOLECULAR BIOLOGY, 323(2), 237 - 251, Oct. 2002 , Refereed
    Summary:It is known that hen egg white lysozyme (HEWL) forms amyloid fibrils. Since HEWL is one of the proteins that have been studied most extensively and is closely related to human lysozyme, the variants of which form the amyloid fibrils that are related to hereditary systemic amyloidosis, this protein is an ideal model to study the mechanism of amyloid fibril formation. In order to gain an insight into the mechanism of amyloid fibril formation, systematic and detailed studies to detect and characterize various structural states of HEWL were conducted. Since HEWL forms amyloid fibrils in highly concentrated ethanol solutions, solutions of various concentrations of HEWL in various concentrations of ethanol were prepared, and the structures of HEWL in these solutions were investigated by small-angle X-ray and neutron scattering. It was shown that the structural states of HEWL were distinguished as the monomer state, the state of the dimer formation, the state of the protofilament formation, the protofilament state, and the state towards the formation of amyloid fibrils. A phase diagram of these structural states was obtained as a function of protein, water and ethanol concentrations. It was found that under the monomer state the structural changes of HEWL were not gross changes in shape but local conformational changes, and the dimers, formed by the association at the end of the long axis of HEWL, had an elongated shape. Circular dichroism measurements showed that the large changes in the secondary structures of HEWL occurred during dimer formation. The protofilaments were formed by stacking of the dimers with their long axis (nearly) perpendicular to and rotated around the protofilament axis to form a helical structure. These protofilaments were characterized by their radius of gyration of the cross-section of 2.4 nm and the mass per unit length of 16,000(+/-2300) Da/ nm. It was shown that the changes of the structural states towards the amyloid fibril formation occurred via lateral association of the protofilaments. A pathway of the amyloid fibril formation of HEWL was proposed from these results. (C) 2002 Elsevier Science Ltd. All rights reserved.
  • Denaturation and aggregation of hen egg lysozyme in aqueous ethanol solution studied by dynamic light scattering, S Tanaka, Y Oda, M Ataka, K Onuma, S Fujiwara, Y Yonezawa, BIOPOLYMERS, BIOPOLYMERS, 59(5), 370 - 379, Oct. 2001 , Refereed
    Summary:We applied dynamic light scattering technique on the model system of hen egg lysozyme in salt free aqueous ethanol solution to study the mechanism of denaturation and aggregation of protein. At low ethanol concentration [0-63% (v/v)], the fast relaxation mode it-as observed, which was caused by lysozyme molecules in the solution interacting with each other with strong repulsive electrostatic force. At 45 and 63% (v/v) ethanol, the slow relaxation mode was also observed, which showed translational diffusive nature, similar to that observed in salt free polyelcetrolyte solution. At 72 or 81% (v/v) ethanol, the slow mode disappeared, leaving only the fast mode. However, the mutual diffusion coefficients obtained from the fast mode at 72 and 81% (v/v) ethanol decreased by about one order of magnitude compared with those from the fast mode at 0-63% (v/v). The reported alcohol-induced conformational transformation of lysozyme molecules at > 60% (v/v) ethanol from their native structure to an alpha -helix-rich structure might cause such drastic decrease in the mutual diffusion coefficients. At the highest ethanol concentration of 90% (v/v), the slow mode reappeared, and its relaxation rate was decreasing with elapsed time, which is possibly due to the growth of aggregates of lysozyme molecules. X-ray diffraction results suggested that the intermolecular beta -sheet formation caused the aggregation. Thus, our results indicated that the change in molecular structure of lysozyme closely relates to the diffusion of molecules and their aggregation. (C) 2001 John Wiley & Sons, Inc.
  • Structural information on the DNA-binding protein HU in solution obtained by the small-angle neutron scattering experiments, S. Fujiwara, Y. Yonezawa, Journal of Physics and Chemistry of Solids, Journal of Physics and Chemistry of Solids, 60(8), 1393 - 1395, 1999 , Refereed
    Summary:Small-angle neutron scattering experiments of the DNA-binding protein HU have been performed. It is suggested from the molecular weight estimation of HU in H2O and the analysis of the scattering curves of HU at various concentrations in D2O that HU is in equilibrium between dimers and tetramers in solution. Comparison with the atomic coordinates of the HU dimer determined with NMR suggested that the distance between the center of gravity of the dimers in the HU tetramer is about 4 nm.
  • Measurement of the running of effective QED coupling at large momentum transfer in the spacelike region, S Odaka, K Abe, K Amako, Y Arai, Y Asano, M Chiba, Y Chiba, M Daigo, M Fukawa, Y Fukushima, J Haba, H Hamasaki, Y Hemmi, M Higuchi, T Hirose, Y Homma, N Ishihara, Y Iwata, J Kanzaki, R Kikuchi, T Kondo, TT Korhonen, H Kurashige, EK Matsuda, T Matsui, K Miyake, S Mori, Y Nagashima, Y Nakagawa, T Nakamura, Nakano, I, K Ogawa, T Ohama, T Ohsugi, H Ohyama, K Okabe, A Okamoto, A Ono, J Pennanen, H Sakamoto, M Sakuda, M Sato, N Sato, M Shioden, J Shirai, T Sumiyoshi, Y Takada, F Takasaki, M Takita, N Tamura, K Tobimatsu, T Tsuboyama, S Uehara, Y Unno, T Watanabe, Y Watase, F Yabuki, Y Yamada, T Yamagata, Y Yonezawa, H Yoshida, PHYSICAL REVIEW LETTERS, PHYSICAL REVIEW LETTERS, 81(12), 2428 - 2431, Sep. 1998 , Refereed
    Summary:The q(2) running of effective QED coupling alpha(q(2)) is measured in a spacelike region, (10 GeV)(2) less than or equal to -q(2) less than or equal to (54 GeV)(2), using Bhabha-scattering and muon-pair production data at e(+)e(-) collisions with a center-of-mass energy of 57.77 GeV. The result verifies the prediction of a theoretical estimation with a precision of better than 1% in terms of alpha(q(2))/alpha(t(0)) with t(0) = -(10 GeV)(2).
  • A neutron diffractometer for biological macromolecules using neutron imaging plates, S Fujiwara, Y Karasawa, Tanaka, I, Y Minezaki, Y Yonezawa, N Niimura, PHYSICA B, PHYSICA B, 241, 207 - 209, Dec. 1997 , Refereed
    Summary:Neutron imaging plates (NIPs), developed recently, have a good spatial resolution and availability of a large sensitive area. The NIPs having such characteristics may be particularly useful for neutron-diffraction measurements of biological macromolecules. We have constructed a neutron diffractometer dedicated to crystallography of biological macro-molecules using the NIP, in the guide hall of the reactor JRR-3M at Japan Atomic Energy Research Institute. Neutrons are monochromatized with an elastically-bent-silicon monochromator (lambda = 0.22 nm). The diffraction patterns are detected with the NIP of 400 x 520 mm(2) at a distance of 150-300 mm from a sample crystal. A sequence of the measurements (exposure, reading the NIP, erasure of the pattern, and starting the next exposure) is done automatically. We measured the diffraction patterns from hen egg-white lysozyme crystals, and obtained the patterns which can be processed to derive integrated intensity of each diffraction spot. (C) 1998 Elsevier Science B.V. All rights reserved.
  • Measurement of the proton-antiproton pair production from two-photon collisions at TRISTAN, H. Hamasaki, K. Abe, K. Amako, Y. Arai, Y. Asano, M. Chiba, Y. Chiba, M. Daigo, M. Fukawa, Y. Fukushima, J. Haba, H. Hanai, Y. Hemmi, M. Higuchi, T. Hirose, Y. Homma, N. Ishihara, Y. Iwata, J. Kanzaki, R. Kikuchi, T. Kondo, T. T. Korhonen, H. Kurashige, E. K. Matsuda, T. Matsui, K. Miyake, S. Mori, Y. Nagashima, Y. Nakagawa, T. Nakamura, I. Nakano, S. Odaka, K. Ogawa, T. Ohama, T. Ohsugi, H. Ohyama, K. Okabe, A. Okamoto, A. Ono, J. Pennanen, H. Sakamoto, M. Sakuda, M. Sato, N. Sato, M. Shioden, J. Shirai, T. Sumiyoshi, Y. Takada, F. Takasaki, M. Takita, N. Tamura, D. Tatsumi, K. Tobimatsu, T. Tsuboyama, S. Uehara, Y. Unno, T. Watanabe, Y. Watase, F. Yabuki, Y. Yamada, T. Yamagata, Y. Yonezawa, H. Yoshida, K. Yusa, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 407(2), 185 - 192, Aug. 28 1997 , Refereed
    Summary:The cross section of the γγ → pp̄ reaction was measured at two-photon center-of-mass energy (Wγγ) between 2.2 and 3.3 GeV, using the two-photon process at an e+ e- collider, TRISTAN. The Wγγ dependence of the cross section integrated over a c.m. angular region of |cos θ*| < 0.6 is in good agreement with the previous measurements and the theoretical prediction based on diquark model in the high Wγγ region. © 1997 Published by Elsevier Science B.V.
  • Precise measurement of Bhabha scattering at a center-of-mass energy of 57.77 GeV, T. Arima, S. Odaka, K. Ogawa, J. Shirai, T. Tsuboyama, N. Hosoda, M. Miura, K. Abe, K. Amako, Y. Arai, Y. Asano, M. Chiba, Y. Chiba, M. Daigo, M. Fukawa, Y. Fukushima, J. Haba, H. Hamasaki, H. Hanai, Y. Hemmi, M. Higuchi, T. Hirose, Y. Homma, N. Ishihara, Y. Iwata, J. Kanzaki, R. Kikuchi, T. Kondo, T. T. Korhonen, H. Kurashige, E. K. Matsuda, T. Matsui, K. Mikaye, S. Mori, Y. Nagashima, Y. Nakagawa, T. Nakamura, I. Nakano, T. Ohama, T. Ohsugi, H. Ohyama, K. Okabe, A. Okamoto, A. Ono, J. Pennanen, H. Sakamoto, M. Sakuda, M. Sato, N. Sato, M. Shioden, T. Sumiyoshi, Y. Takada, F. Takasaki, M. Takita, N. Tamura, D. Tatsumi, K. Tobimatsu, S. Uehara, Y. Unno, T. Watanabe, Y. Watase, F. Yabuki, Y. Yamada, T. Yamagata, Y. Yonezawa, H. Yoshida, K. Yusa, Physical Review D - Particles, Fields, Gravitation and Cosmology, Physical Review D - Particles, Fields, Gravitation and Cosmology, 55(1), 19 - 39, 1997 , Refereed
    Summary:Bhabha scattering at a center-of-mass energy of 57.77 GeV has been measured using the VENUS detector at KEK TRISTAN. The precision is better than 1% in scattering angle regions of cosθ�0.743 and 0.822�cosθ�0.968. A model-independent scattering-angle distribution is extracted from the measurement. The distribution is in good agreement with the prediction of the standard electroweak theory. The sensitivity to underlying theories is examined, after unfolding the photon-radiation effect. The [Formula presented] dependence of the photon vacuum polarization, frequently interpreted as a running of the QED fine-structure constant, is directly observed with a significance of three standard deviations. The [Formula presented] exchange effect is clearly seen when the distribution is compared with the prediction from QED (photon exchanges only). The agreement with the standard theory leads us to constraints on extensions of the standard theory. In all quantitative discussions, correlations in the systematic error between angular bins are taken into account by employing an error matrix technique. © 1997 The American Physical Society.
  • A neutron diffractometer for biological macromolecules using neutron imaging plates, S. Fujiwara, Y. Karasawa, I. Tanaka, Y. Minezaki, Y. Yonezawa, N. Niimura, Physica B: Condensed Matter, Physica B: Condensed Matter, 241-243, 207 - 209, 1997 , Refereed
    Summary:Neutron imaging plates (NIPs), developed recently, have a good spatial resolution and availability of a large sensitive area. The NIPs having such characteristics may be particularly useful for neutron-diffraction measurements of biological macromolecules. We have constructed a neutron diffractometer dedicated to crystallography of biological macromolecules using the NIP, in the guide hall of the reactor JRR-3M at Japan Atomic Energy Research Institute. Neutrons are monochromatized with an elastically-bent-silicon monochromator (λ = 0.22 nm). The diffraction patterns are detected with the NIP of 400 × 520 mm2 at a distance of 150-300 mm from a sample crystal. A sequence of the measurements (exposure, reading the NIP, erasure of the pattern, and starting the next exposure) is done automatically. We measured the diffraction patterns from hen egg-white lysozyme crystals, and obtained the patterns which can be processed to derive integrated intensity of each diffraction spot. © 1998 Elsevier Science B.V. All rights reserved.
  • Measurement of open charm production in two-photon processes with detection of electron-inclusive events, S. Uehara, K. Abe, K. Amako, Y. Arai, T. Arima, Y. Asano, M. Chiba, Y. Chiba, M. Daigo, M. Fukawa, Y. Fukushima, J. Haba, H. Hanai, Y. Hemmi, M. Higuchi, F. Hinode, T. Hirose, Y. Homma, N. Hosoda, N. Ishihara, Y. Iwata, N. Kanda, N. Kanematsu, J. Kanzaki, R. Kikuchi, T. Kondo, T. T. Korhonen, A. Krüger, H. Kurashige, J. MacNaughton, E. K. Matsuda, T. Matsui, M. Miura, K. Miyake, S. Mori, Y. Nagashima, Y. Nakagawa, T. Nakamura, I. Nakano, S. Odaka, K. Ogawa, T. Ohama, T. Ohsugi, H. Ohyama, A. Okamoto, A. Ono, T. Oyama, H. Sakamoto, M. Sakuda, M. Sato, N. Sato, M. Shioden, J. Shirai, M. Shirakata, T. Sumiyoshi, A. Suzuki, Y. Takada, H. Takaki, F. Takasaki, M. Takita, N. Tamura, K. Tobimatsu, T. Tsuboyama, Y. Unno, M. Utsumi, Y. Watase, F. Yabuki, Y. Yamada, T. Yamagata, Y. Yamamoto, Y. Yonezawa, H. Yoshida, Zeitschrift für Physik C Particles and Fields, Zeitschrift für Physik C Particles and Fields, 63(2), 213 - 218, Jun. 1994 , Refereed
    Summary:Experimental studies of open charm production in two-photon processes have been performed. In the measurement, charmed hadrons were identified by electrons from their semi-leptonic decays. The result was compared with calculations based on the direct process and photon-gluon fusion process by resolved photons. We found that the effect of the gluon component in a photon is substantial in the observed events. © 1994 Springer-Verlag.
  • A study of charged D* production in e+ e- annihilation at an average center-of-mass energy of 58 GeV, F. Hinode, K. Abe, K. Amako, Y. Arai, T. Arima, Y. Asano, M. Chiba, Y. Chiba, M. Daigo, M. Fukawa, Y. Fukushima, J. Haba, Y. Hemmi, M. Higuchi, T. Hirose, Y. Homma, Y. Hoshi, N. Hosoda, N. Ishihara, N. Kanda, E. Kanatani, N. Kanematsu, J. Kanzaki, R. Kikuchi, T. T. Korhonen, T. Kondo, A. E. Krüger, H. Kurashige, J. MacNaughton, T. Matsui, M. Miura, K. Miyake, S. Mori, Y. Nagashima, T. Nakamura, I. Nakano, S. Odaka, T. Ogawa, T. Ohama, T. Ohsugi, A. Okamoto, A. Ono, T. Oyama, H. Ohyama, H. Sakamoto, M. Sakuda, M. Sato, N. Sato, M. Shioden, J. Shirai, M. Shirakata, T. Sumiyoshi, A. Suzuki, Y. Takada, H. Takaki, F. Takasaki, M. Takita, N. Tamura, K. Tobimatsu, T. Tsuboyama, S. Uehara, Y. Unno, M. Utsumi, Y. Watase, F. Yabuki, Y. Yamada, T. Yamagata, Y. Yonezawa, H. Yoshida, Physics Letters B, Physics Letters B, 313(1-2), 245 - 252, Aug. 26 1993 , Refereed
    Summary:We have studied the production of charged D* mesons in e+ e- annihilation at an average center-of-mass energy of 58.0 GeV. Charged D* mesons were identified using two independent methods the mass-difference method and the detection of the low transverse-momentum pion. The forward-backward asymmetry of the charm quark production was measured to be Ac= -0.61±0.13(stat.)±0.08(syst.). The cross section of inclusive D* production was found to be σ(e+ e-→D* ±+X) = 24.5 ± 5.3 (stat.)±3.0(syst.) pb. If we assume the standard model prediction for the charm quark production, we obtain the branching ratio for the charm quark to produce a charged D* meson to be Br(c→D*+ + X) = (22±5(stat.)±3(syst.))%. © 1993.
  • NO 17 KEV NEUTRINO - ADMIXTURE LESS-THAN 0.073-PERCENT (95-PERCENT CL), T OHSHIMA, H SAKAMOTO, T SATO, J SHIRAI, T TSUKAMOTO, Y SUGAYA, K TAKAHASHI, T SUZUKI, C ROSENFELD, S WILSON, K UENO, Y YONEZAWA, H KAWAKAMI, S KATO, S SHIBATA, K UKAI, PHYSICAL REVIEW D, PHYSICAL REVIEW D, 47(11), 4840 - 4856, Jun. 1993 , Refereed
    Summary:To solve the controversial issue concerning the possible existence of a 17 keV neutrino with a 1% admixture in nuclear beta decay, we searched directly for any evidence of a production-threshold effect. The Ni-63 beta spectrum was measured with a magnetic spectrometer, with very high statistics along with a fine energy scan over a narrow energy region around the expected threshold. The obtained mixing strength was \U\2 = [-0.011 +/- 0.033(stat)+/-0.030(syst)]%, very consistent with zero, and decisively excluding the existence of a 17 keV neutrino admixing at the 1% level with the electron neutrino. The corresponding upper limit was set at \U\2<0.073% (95% C.L.). A new limit was also obtained for a wider mass range: \U\2 <0.15% (95% C.L.) for 10.5 to 25.0 keV neutrinos.
  • HIGH-SENSITIVITY SEARCH FOR A 17 KEV NEUTRINO - NEGATIVE INDICATION WITH AN UPPER LIMIT OF 0.095-PERCENT, H KAWAKAMI, S KATO, T OHSHIMA, C ROSENFELD, H SAKAMOTO, T SATO, S SHIBATA, J SHIRAI, Y SUGAYA, T SUZUKI, K TAKAHASHI, T TSUKAMOTO, K UENO, K UKAI, S WILSON, Y YONEZAWA, PHYSICS LETTERS B, PHYSICS LETTERS B, 287(1-3), 45 - 50, Aug. 1992 , Refereed
    Summary:We have performed a search for a 17 keV neutrino by looking for a kink in the Ni-63 beta-spectrum near the expected energy threshold. Using a large number of events (2.4 x 10(9)) accumulated in a narrow energy region with the INS iron-free pi square-root 2 beta-spectrometer, we obtain a mixing strength of [1.8 +/- 3.3 (stat.) +/- 3.3 (syst.)] X 10(-4), and no indication of the presence of a 17 keV neutrino with the order of 1% mixing. We set an upper limit of 0.095% for the admixture of a neutrino with a mass of 17 keV and of 0.1% with a mass range of 10-24 keV, at the 95% confidence level.
  • SEARCH FOR CHARGED SCALARS IN E+E- ANNIHILATION UP TO 64 GEV CM ENERGY, T YUZUKI, J HABA, K ABE, K AMAKO, Y ARAI, Y ASANO, M CHIBA, Y CHIBA, M DAIGO, M FUKAWA, T FUKUI, Y FUKUSHIMA, Y HEMMI, M HIGUCHI, F HINODE, T HIROSE, Y HOJYO, Y HOMMA, Y HOSHI, N ISHIHARA, T KAMITANI, N KANEMATSU, N KANDA, J KANZAKI, R KIKUCHI, T KONDO, TT KORHONEN, T KOSEKI, H KURASHIGE, J MACNAUGHTON, T MATSUI, M MINAMI, K MIYAKE, S MORI, Y NAGASHIMA, T NAKAMURA, NAKANO, I, Y NARITA, S ODAKA, K OGAWA, T OHAMA, T OHSUGI, A OKAMOTO, A ONO, T OYAMA, H SAKAMOTO, M SAKUDA, N SASAO, M SATO, H SHIBUYA, M SHIODEN, J SHIRAI, M SHIRAKATA, S SUGIMOTO, T SUMIYOSHI, A SUZUKI, Y TAKADA, H TAKAKI, F TAKASAKI, A TAKETANI, M TAKITA, N TAMURA, N TERUNUMA, K TOBIMATSU, T TSUBOYAMA, S UEHARA, Y UNNO, M UTSUMI, T WATANABE, Y WATASE, F YABUKI, Y YAMADA, Y YONEZAWA, H YOSHIDA, PHYSICS LETTERS B, PHYSICS LETTERS B, 267(2), 309 - 316, Sep. 1991 , Refereed
    Summary:A search for the production of charged scalars has been carried out in e+e- annihilation at center of mass energies up to 64 GeV with 61.1 pb-1 of integrated luminosity using the VENUS detector at TRISTAN. The assumptions concerning the production and decay of hypothetical charged scalars are minimal; they are expected to be singly charged and decay into a pair of fermions. No positive evidence for their production has been found in a study of all combinations of the lBARv(lvBAR) and UDBAR(UBARD) decay channels. We have excluded the mass region of 8.0-20.0 GeV/c2 regardless of the decay mode.
  • Experimental study of color degree of freedom of gluons in e+e- annihilation at s around 60 GeV, K. Abe, K. Amako, Y. Arai, Y. Asano, M. Chiba, Y. Chiba, M. Daigo, T. Emura, M. Fukawa, T. Fukui, Y. Fukushima, J. Haba, Y. Hemmi, M. Higuchi, T. Hirose, Y. Hojyo, Y. Homma, Y. Hoshi, Y. Ikegami, N. Ishihara, T. Kamitani, N. Kanematsu, J. Kanzaki, R. Kikuchi, T. Kondo, T. T. Korhonen, T. Koseki, H. Kurashige, T. Matsui, M. Minami, K. Miyake, S. Mori, Y. Nagashima, T. Nakamura, I. Nakano, Y. Narita, S. Odaka, K. Ogawa, T. Ohama, T. Ohsugi, A. Okamoto, A. Ono, T. Oyama, H. Sakamoto, M. Sakuda, N. Sasao, M. Sato, M. Shioden, J. Shirai, M. Shirakata, S. Sugimoto, T. Sumiyoshi, A. Suzuki, Y. Suzuki, Y. Takada, F. Takasaki, A. Taketani, M. Takita, N. Tamura, R. Tanaka, N. Terunuma, K. Tobimatsu, T. Tsuboyama, S. Uehara, Y. Unno, M. Utsumi, M. Wakai, T. Watanabe, Y. Watase, F. Yabuki, Y. Yamada, T. Yamagata, Y. Yonezawa, H. Yoshida, Physical Review Letters, Physical Review Letters, 66(3), 280 - 284, 1991 , Refereed
    Summary:We have studied four-jet angular distributions using data collected with the VENUS detector at the KEK e+e- collider at TRISTAN at c.m. energies between 54 and 64 GeV. The obseved angular distributions are consistent with QCD, but are inconsistent with the Abelian gluon model at the 5% significance level. We have further obtained 95%-confidence experimental bounds on the fundamental parameters of the SU(Nc) local color symmetry. © 1991 The American Physical Society.
  • MEASUREMENT OF R AND SEARCH FOR NEW QUARK FLAVORS DECAYING INTO MULTI-JET FINAL-STATES IN E+E- COLLISIONS BETWEEN 54.0 AND 61.4 GEV CM ENERGIES, K ABE, K AMAKO, Y ARAI, Y ASANO, M CHIBA, Y CHIBA, M DAIGO, T EMURA, ENDO, I, M FUKAWA, T FUKUI, Y FUKUSHIMA, J HABA, D HAIDT, HAYASHIBARA, I, Y HEMMI, M HIGUCHI, T HIROSE, Y HOJYO, Y HOMMA, Y HOSHI, Y IKEGAMI, N ISHIHARA, T KAMITANI, N KANEMATSU, J KANZAKI, R KIKUCHI, T KONDO, T KOSEKI, H KURASHIGE, T MATSUI, M MINAMI, K MIYAKE, S MORI, Y NAGASHIMA, T NAKAMURA, NAKANO, I, Y NARITA, S ODAKA, K OGAWA, T OHAMA, T OHSUGI, A OKAMOTO, A ONO, H OSABE, T OYAMA, H SAITO, H SAKAE, H SAKAMOTO, S SAKAMOTO, M SAKANO, M SAKUDA, N SASAO, M SATO, M SHIODEN, J SHIRAI, S SHIRAKATA, S SUGIMOTO, T SUMIYOSHI, A SUZUKI, Y SUZUKI, Y TAKADA, F TAKASAKI, A TAKETANI, M TAKITA, N TAMURA, R TANAKA, N TERUNUMA, K TOBIMATSU, T TSUBOYAMA, A TSUKAMOTO, S UEHARA, Y UNNO, M UTSUMI, M WAKAI, T WATANABE, Y WATASE, F YABUKI, Y YAMADA, T YAMAGATA, T YAMASHITA, Y YONEZAWA, H YOSHIDA, PHYSICS LETTERS B, PHYSICS LETTERS B, 234(3), 382 - 388, Jan. 1990 , Refereed
  • SEARCH FOR ISOLATED PHOTONS FROM FLAVOR-CHANGING NEUTRAL-CURRENT DECAY OF A NEW QUARK AT THE KEK E+E- COLLIDER TRISTAN, K ABE, K AMAKO, Y ARAI, Y ASANO, M CHIBA, Y CHIBA, M DAIGO, T EMURA, ENDO, I, M FUKAWA, T FUKUI, Y FUKUSHIMA, J HABA, D HAIDT, HAYASHIBARA, I, Y HEMMI, M HIGUCHI, T HIROSE, Y HOJO, Y HOMMA, Y HOSHI, Y IKEGAMI, N ISHIHARA, T KAMITANI, N KANEMATSU, J KANZAKI, R KIKUCHI, T KONDO, T KOSEKI, H KURASHIGE, T MATSUI, M MINAMI, K MIYAKE, S MORI, Y NAGASHIMA, T NAKAMURA, NAKANO, I, Y NARITA, S ODAKA, K OGAWA, T OHAMA, T OHSUGI, A OKAMOTO, A ONO, H OSABE, T OYAMA, H SAITO, H SAKAE, H SAKAMOTO, S SAKAMOTO, M SAKANO, M SAKUDA, N SASAO, M SATO, M SHIODEN, J SHIRAI, S SUGIMOTO, T SUMIYOSHI, Y SUZUKI, Y TAKADA, F TAKASAKI, A TAKETANI, N TAMURA, R TANAKA, N TERUNUMA, K TOBIMATSU, T TSUBOYAMA, A TSUKAMOTO, S UEHARA, Y UNNO, M UTSUMI, M WAKAI, T WATANABE, Y WATASE, Y YAMADA, T YAMAGATA, T YAMASHITA, Y YONEZAWA, H YOSHIDA, PHYSICAL REVIEW LETTERS, PHYSICAL REVIEW LETTERS, 63(17), 1776 - 1779, Oct. 1989 , Refereed
  • New Limits on Neutral Scalar Bosons, Shigeru Odaka, Takahiko Kondo, Koya Abe, Yasuo Arai, Yuzo Asano, Toru Fukui, Junji Haba, Takuya Kamitani, Ryusaburo Kikucm, Masayuki Minami, Taro Ohama, Takashi Ohsugi, Shizuo Sakamoto, Junpei Shirai, Shojiro Sugimoto, Yoichiro Suzuki, Atsushi Taketani, Norio Tamura, Keijiro Tobimatsu, Akira Tsukamoto, Michiaki Utsumi, Taketora Yamagata, Journal of the Physical Society of Japan, Journal of the Physical Society of Japan, 58(9), 3037 - 3041, 1989 , Refereed
    Summary:A possible contribution of neutral scalar bosons to the cross section of multihadron production at e+e- collisions was examined at center-of-mass energies between 55.0 and 60.8 GeV by taking into account first-order radiative corrections. We found no positive evidence and established new upper limits on the coupling parameter of the scalars. © 1989, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.

Conference Activities & Talks

  • On-the-fly determination of averaged structure of proteins and the analyses using Baysian inference method, Yasushige Yonezawa,   2018 06 27

Misc

  • Conserved Trp in the adjacent S4 helices cooperatively produce the sustained-deactivation in the voltage-gated H+ channel dimer, Okuda H, Yonezawa Y, Takano Y, Okamura Y, Fujiwara Y, Journal of Physiological Sciences, 65, Supplement1, S119,   2015 , Refereed
  • Precise measurement of the [Formula presented] reaction at [Formula presented], M. Miura, S. Odaka, T. Arima, K. Tobimatsu, K. Ogawa, J. Shirai, T. Tsuboyama, K. Abe, K. Amako, Y. Arai, Y. Asano, M. Chiba, Y. Chiba, M. Daigo, M. Fukawa, Y. Fukushima, J. Haba, H. Hamasaki, Y. Hemmi, M. Higuchi, T. Hirose, Y. Homma, N. Ishihara, Y. Iwata, J. Kanzaki, R. Kikuchi, T. Kondo, T. T. Korhonen, H. Kurashige, E. K. Matsuda, T. Matsui, K. Miyake, S. Mori, Y. Nagashima, Y. Nakagawa, T. Nakamura, I. Nakano, T. Ohama, T. Ohsugi, H. Ohyama, K. Okabe, A. Okamoto, A. Ono, J. Pennanen, H. Sakamoto, M. Sakuda, M. Sato, N. Sato, M. Shioden, T. Sumiyoshi, Y. Takada, F. Takasaki, M. Takita, N. Tamura, D. Tatsumi, S. Uehara, Y. Unno, T. Watanabe, Y. Watase, F. Yabuki, Y. Yamada, T. Yamagata, Y. Yonezawa, H. Yoshida, K. Yusa, Physical Review D - Particles, Fields, Gravitation and Cosmology, 57, 5345, 5362,   1998 01 01 , 10.1103/PhysRevD.57.5345, https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=0007102858&origin=inward
    Summary:The reaction (Formula presented) has been measured at (Formula presented) based on (Formula presented) data collected with the VENUS detector at TRISTAN. The production cross section is measured in bins of the production angle within an angular acceptance of (Formula presented) according to a model-independent definition. The result is consistent with the prediction of the standard electroweak theory. Although a trend in measurements at lower energies that the total cross section tends to be smaller than the prediction remains, the discrepancy is not significant. The model-independent result is converted to the differential cross section in the effective-Born scheme by unfolding photon-radiation effects. This result can be extrapolated to quantities for the full solid angle as (Formula presented) and (Formula presented) by imposing an ordinary assumption on the production-angle dependence. The converted results are used to set constraints on extensions of the standard theory. S-matrix parametrization, and possible contributions from contact interactions and heavy neutral-scalar exchanges are examined. © 1998 The American Physical Society.
  • SEARCH FOR A 4TH-GENERATION QUARK WITH ABSOLUTE-VALUE OF Q = E/3 IN E+E- COLLISIONS AT SQUARE-ROOT S = 56-57 GEV, K ABE, K AMAKO, Y ARAI, Y ASANO, M CHIBA, Y CHIBA, M DAIGO, T EMURA, ENDO, I, M FUKAWA, T FUKUI, Y FUKUSHIMA, J HABA, D HAIDT, HAYASHIBARA, I, Y HEMMI, M HIGUCHI, T HIROSE, Y HOJYO, Y HOMMA, Y HOSHI, Y IKEGAMI, N ISHIHARA, T KAMITANI, N KANEMATSU, J KANZAKI, R KIKUCHI, T KONDO, T KOSEKI, H KURASHIGE, T MATSUI, M MINAMI, K MIYAKE, S MORI, Y NAGASHIMA, T NAKAMURA, NAKANO, I, Y NARITA, S ODAKA, K OGAWA, T OHAMA, T OHSUGI, A OKAMOTO, A ONO, H OSABE, T OYAMA, H SAITO, H SAKAE, H SAKAMOTO, S SAKAMOTO, M SAKANO, M SAKUDA, N SASAO, M SATO, M SHIODEN, J SHIRAI, S SUGIMOTO, T SUMIYOSHI, Y SUZUKI, Y TAKADA, F TAKASAKI, A TAKETANI, N TAMURA, R TANAKA, N TERUNUMA, K TOBIMATSU, T TSUBOYAMA, A TSUKAMOTO, S UEHARA, Y UNNO, M UTSUMI, M WAKAI, T WATANABE, Y WATASE, Y YAMADA, T YAMAGATA, T YAMASHITA, Y YONEZAWA, H YOSHIDA, PHYSICAL REVIEW D, 39, 11, 3524, 3527,   1989 06