排序方式: 共有37条查询结果,搜索用时 31 毫秒
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Masahito Segi Mamoru Takahashi Tadashi Nakajima Sohei Suga
Shinji Murai
Noboru Sonoda 《Tetrahedron letters》1988,29(52):6965-6968Intramolecular Dieis-Alder reaction of selenoaldehydes which were generated from bis(trimethylsilyl) selenide and dienals gave the corresponding bicyclic adducts. 相似文献
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Yang Jiahao Yabuno Hiroshi Yanagisawa Naoki Yamamoto Yasuyuki Matsumoto Sohei 《Nonlinear dynamics》2020,102(4):1987-1996
Nonlinear Dynamics - In this study, a method of measuring the added mass for an object oscillating in a viscous fluid using nonlinear self-excited oscillations was developed. The added mass... 相似文献
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Yukio Yokoyama Masanori Watanabe Sohei Horikoshi Hisakuni Sato 《Analytical sciences》2002,18(1):59-63
A low-capacity cation-exchange column was newly developed for the separation of amino acids. A highly cross-linked macro-porous polystyrene-divinylbenzene co-polymer was functionalized by a sulfoacylation reaction. The exchange capacity was controllable at the acylation step. The capacity between 55 and 60 micromol/column was adequate for the practical separations in acceptable retention times. The 5-microm base polymers having average pore diameters smaller than 3 nm gave satisfactory results, and those having 1.5-nm pore was most favorable. Several isocratic elution conditions at different pH values adjusted by phosphate buffer of mM order with or without acetonitrile could provide good separations for individual classes of amino acids, i.e., acidic, neutral, hydrophobic, and basic groups. The results provided fundamental data for constructing gradient elution systems required for the simultaneous separation of protein amino acids. 相似文献
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Background
Primary auditory cortex (AI) neurons show qualitatively distinct response features to successive acoustic signals depending on the inter-stimulus intervals (ISI). Such ISI-dependent AI responses are believed to underlie, at least partially, categorical perception of click trains (elemental vs. fused quality) and stop consonant-vowel syllables (eg.,/da/-/ta/continuum). 相似文献26.
Akai S Tanimoto K Kanao Y Omura S Kita Y 《Chemical communications (Cambridge, England)》2005,(18):2369-2371
The title domino reactions were developed to directly provide tetrahydrofuro[3,4-c]isoxazole derivatives (5 and 9) in > or =90% ee from racemic alpha-hydroxynitrones (2 and 6), which were used in the concise asymmetric total synthesis of (-)-rosmarinecine . 相似文献
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In order to understand the role of iron (Fe) in the oxidative stress underlying the pathogenesis of Parkinson's disease (PD) and parkinsonism–dementia complex (PDC), we investigate distributions and chemical states of Fe within a single neuron of the two disease cases, using synchrotron radiation (SR) micro beam. In the X-ray fluorescence (XRF) spectroscopic study, an excessive accumulation of Fe can be seen in the melanized neurons and free-neuromelanin (MN) aggregates in the substantia nigra tissue of both PD and PDC midbrains. X-ray absorption near-edge structure (XANES) analyses of PD revealed that the chemical state of Fe in the melanized neurons and free-MN aggregates shifted toward Fe3+ with a pre-edge peak at Fe K-edge due to a 1s 3d transition, indicating a breaking of the inversion symmetry around the Fe site. In PDC, however, the melanized neurons and free-MN aggregates showed mixed states of Fe2+ and Fe3+ without any pre-edge peak in the spectra. This tendency was also observed in the control case. These results suggest that the changes in distributions and chemical states of Fe may endogenously play a crucial role in the oxidative damage of the melanized neurons in PD, but through a different mechanism other than PDC. 相似文献
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Sohei Ashida 《Annales Henri Poincare》2016,17(8):2173-2197
We obtain a reduction scheme for the study of the quantum evolution of an atom in constant magnetic fields using the method developed by Martinez, Nenciu and Sordoni based on the construction of almost invariant subspace. In Martinez and Sordoni (Mem AMS 936, 2009) such a case is also studied but their reduced Hamiltonian includes the vector potential terms. In this paper, using the center of mass coordinates and constructing the almost invariant subspace different from theirs, we obtain the reduced Hamiltonian which does not include the vector potential terms of the nucleus. Using the reduced evolution, we also obtain the asymptotic expansion of the evolution for a specific localized initial data, which verifies the straight motion of an atom in constant magnetic fields. 相似文献
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Abstract— On treatment with 8-methoxypsoralen plus near UV light, an excisionless ( uvrB- ) strain of Escherichia coli showed about 3– and 10 times higher sensitivities to killing and mutation, respectively, than its parental strain. On re-irradiation with near UV in the absence of unbound psoralen, the uvrB- strain pretreated with psoralen plus near UV showed a decrease in both survival and mutation. After treatment with psoralen plus near UV, re-irradiation of T7 DNA in the absence of unbound psoralen caused an increase in the cross-linked fraction with an equivalent decrease in the non-cross-linked fraction. From these and previous results, we conclude that monoadducts produced by treatment with psoralen plus near UV are converted to cross-links by further irradiation and that, in E. coli , monoadducts are responsible for the mutation induced by psoralen-plus-light whereas cross-links are the major cause of its lethal action. 相似文献