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1,611 results on '"Ohnishi S"'

5. Three-body structure of the $nn\Lambda$ system with $\Lambda N-\Sigma N$ coupling

Author

Hiyama, E., Ohnishi, S., Gibson, B. F., and Rijken, Th. A.

Subjects
Nuclear Theory
Abstract

The structure of the three-body $nn\Lambda$ system, which has been observed recently by the HypHI collaboration, is investigated taking $\Lambda N-\Sigma N$ coupling explicitly into account. The $YN$ and $NN$ interactions employed in this work reproduce the binding energies of $^3_{\Lambda}$H, $^4_{\Lambda}$H and $^4_{\Lambda}$He. We do not find any $^3_{\Lambda}n$ bound state, which contradicts the interpretation of the data reported by the HypHI collaboration., Comment: To be publsihed in PRC as a Rapid communication

Published
2014
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6. Four-body structure of neutron-rich hypernucleus $^6_{\Lambda}$H

Author

Hiyama, E., Ohnishi, S., Kamimura, M., and Yamamoto, Y.

Subjects
Nuclear Theory
Abstract

The structure of heavy hyperhydrogen $^6_{\Lambda}$H is studied within the framework of a $tnn\Lambda$ four-body cluster model. Interactions among the constituent subunits are determined so as to reproduce reasonably well the observed low-energy properties of the $tn, t\Lambda$ and $tnn$ subsystems. As long as we reproduce the energy and width of $^5$H within the error bar, the ground state of $^6_{\Lambda}$H is obtained as a resonant state., Comment: 16 Pages, 3 figures, To be published in Nuclear Physics A

Published
2013
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19. Electronic shell structures in aluminum and noble metal clusters

Author

Ohnishi, S., Araki, H., editor, Brézin, E., editor, Ehlers, J., editor, Frisch, U., editor, Hepp, K., editor, Jaffe, R. L., editor, Kippenhahn, R., editor, Weidenmüller, H. A., editor, Wess, J., editor, Zittartz, J., editor, Beiglböck, W., editor, Schmidt, Rüdiger, editor, Lutz, Hans O., editor, and Dreizler, Reiner, editor

Published
1992
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31. Calculation of static (hyper)polarizabilities for pi-conjugated donor/acceptor molecules and block copolymers by the elongation finite-field method

Author

Ohnishi, S., F.L. Gu, Naka, K., Imamura, A., Kirtman, B., and Aoki, Y.

Subjects
Polarization (Electricity) -- Analysis, Block copolymers -- Electric properties, Electron donor-acceptor complexes -- Research, Chemicals, plastics and rubber industries
Abstract

The elongation finite-field method is applied to calculate static (hyper)polarizabilities of pi-conjugated chains, with donor and/or acceptor substituents, as well as a heterol block copolymer. It is observed that substituent effects on the linear polarizability and second hyperpolarizability are modest, but a large first hyperpolarizability can be induced.

Published
2004

32. Stimulation of perivascular nitric oxide synthesis by oxygen

Author

Thom, Stephen R., Fisher, Donald, Zhang Jie, Bhopale, Veena M. Ohnishi, S. Tsuyoshi, Kotake, Yashige, Ohnishi, Tomoko, and Buerk, Donald G.

Subjects
Nitric oxide -- Research, Biosynthesis -- Research, Heat shock proteins -- Research, Calmodulin -- Research, Hyperbaric oxygenation -- Research, Biological sciences
Abstract

We hypothesized that elevated partial pressures of [0.sub.2] would increase perivascular nitric oxide (.NO) synthesis. Rodents with [0.sub.2-] and NO-specific microelectrodes implanted adjacent to the abdominal aorta were exposed to [0.sub.2] at partial pressures from 0.2 to 2.8 atmospheres absolute (ATA). Exposures to 2.0 and 2.8 ATA [0.sub.2] stimulated neuronal (type I) NO synthase (nNOS) and significantly increased steady-state *NO concentration, but the mechanism for enzyme activation differed at each partial pressure. At both pressures, elevations in *NO concentration were inhibited by the nNOS inhibitor 7-nitroindazole and the calcium channel blocker nimodipine. Enzyme activation at 2.0 ATA 02 appeared to be due to an altered cellular redox state. Exposure to 2.8 ATA [0.sub.2], but not 2.0 ATA [0.sub.2], increased nNOS activity by enhancing nNOS association with calmodulin, and an inhibitory effect of geldanamycin indicated that the association was facilitated by heat shock protein 90. Infusion of superoxide dismutase inhibited .NO elevation at 2.8 but not 2.0 ATA [0.sub.2]. Hyperoxia increased the concentration of .NO associated with hemoglobin. These findings highlight the complexity of oxidative stress responses and may help explain some of the dose responses associated with therapeutic applications of hyperbaric oxygen. neuronal nitric oxide synthase; heat shock protein 90; calmodulin; hyperbaric oxygen

Published
2003

39. Spatially confined high-temperature blackbody radiation from C60 films

Author

Wen, C., Ohnishi, S., and Minami, N.

Subjects
Thin films -- Optical properties, Blackbody radiation -- Research, Composite materials -- Electric properties, Carbon allotropes -- Research, Chemicals, plastics and rubber industries
Abstract

The blackbody radiation from C60/Si layered films were studied using green laser irradiation. Intense white light were emitted as a result and the emission spectra from the visible to the mid-infrared areas agrees with Planck's equation for blackbody radiation. The radiation had effective temperatures of 1100-2140 K, and it was shown that these high temperatures were located in the dark islands formed by laser irradiation of the premodified parts in the composite films.

Published
1998

42. DNA strand scission by polycyclic aromatic hydrocarbon omicron-quinones: role of reactive oxygen species, Cu(II) redox cycling, and omicron-semiquinone anion radicals

Author

Flowers, Lynn, Ohnishi, S. Tsuyoshi, and Penning, Trevor M.

Subjects
DNA damage -- Analysis, Active oxygen -- Analysis, Radicals (Chemistry) -- Analysis, Pollutants -- Analysis, Quinone -- Analysis, Polycyclic aromatic compounds -- Analysis, Biological sciences, Chemistry
Abstract

Polycyclic aromatic hydrocarbons (PAH) are environmental pollutants that are believed to cause cancer in humans by damaging DNA. By themselves they are innocuous, but in association with other compounds they may act as potent nucleases. This study aimed to identify which associations of PAH omicron-quinones render them capable of DNA scission. Results showed that NADPH, Cu(II), Cu(I), H2O2, and OH radical were necessary for PAH omicron-quinones to act as nucleases. On the other hand, addition of OH radical scavengers like mannitol, sodium benzoate and formic acid decreased both DNA strand scission and OH radical formation.

Published
1997

50. Effects of human amnion-derived mesenchymal stem cells and conditioned medium in rats with sclerosing cholangitis

Author

Ryo Sugiura, Ohnishi, S., Ohara, M., Ishikawa, M., Miyamoto, S., Onishi, R., Yamamoto, K., Kawakubo, K., Kuwatani, M., and Sakamoto, N.

Subjects
sclerosing cholangitis, alpha-naphthylisothiocyanate, Mesenchymal stem cells, regenerative medicine, Original Article, amnion
Abstract

Mesenchymal stem cells (MSCs) represent a valuable cell source in regenerative medicine, and large numbers of MSCs can be isolated from the amnion noninvasively. Sclerosing cholangitis is a chronic cholestatic disease and characterized by progressive biliary destruction leading to cirrhosis. Many factors are involved in the development of sclerosing cholangitis; however, effective medical therapy is not established. We investigated the effects of human amnion-derived MSCs (hAMSCs) and conditioned medium (CM) obtained from hAMSC cultures in rats with sclerosing cholangitis. Sclerosing cholangitis was induced via the intragastric administration of 100 mg/kg alpha-naphthylisothiocyanate (ANIT) twice weekly for 4 weeks. One million hAMSCs or 200 mu L of CM were intravenously administered on days 15 and 22. Rats were sacrificed on day 29 and evaluated via histological, immunohistochemical, and mRNA expression analyses. hAMSC transplantation and CM administration significantly improved the histological score. In addition, these two interventions significantly improved biliary hyperplasia, peribiliary fibrosis, and inflammation in Glisson's sheath. Accordingly, CK19, MMP-9, and TNF-alpha, and MCP-1 expression in the liver was also decreased by hAMSC and CM administration. In conclusion, hAMSC and CM administration ameliorated biliary hyperplasia, peribiliary fibrosis, and inflammation in a rat model of sclerosing cholangitis. hAMSCs and CM may represent new modalities for treating sclerosing cholangitis.

Published
2018

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