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331 results on '"Kohyama M"'

31. The atomic and electronic structures of NiO(001)/Au(001) interfaces.

Author

Visikovskiy, A., Mitsuhara, K., Hazama, M., Kohyama, M., and Kido, Y.

Subjects
ATOMIC structure, ELECTRONIC structure, PHOTOELECTRON spectroscopy, BAND gaps, CHARGE transfer, MATHEMATICAL models
Abstract

The atomic and electronic structures of NiO(001)/Au(001) interfaces were analyzed by high-resolution medium energy ion scattering (MEIS) and photoelectron spectroscopy using synchrotron-radiation-light. The MEIS analysis clearly showed that O atoms were located above Au atoms at the interface and the inter-planar distance of NiO(001)/Au(001) was derived to be 2.30 ± 0.05 Å, which was consistent with the calculations based on the density functional theory (DFT). We measured the valence band spectra and found metallic features for the NiO thickness up to 3 monolayer (ML). Relevant to the metallic features, electron energy loss analysis revealed that the bandgap for NiO(001)/Au(001) reduced with decreasing the NiO thickness from 10 down to 5 ML. We also observed Au 4f lines consisting of surface, bulk, and interface components and found a significant electronic charge transfer from Au(001) to NiO(001). The present DFT calculations demonstrated the presence of an image charge beneath Ni atoms at the interface just like alkali-halide/metal interface, which may be a key issue to explain the core level shift and band structure. [ABSTRACT FROM AUTHOR]

Published
2013
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33. Nanoparticle arrangement by DNA-programmed self-assembly for catalyst applications.

Author

Maeda, Y., Akita, T., Daté, M., Takagi, A., Matsumoto, T., Fujitani, T., and Kohyama, M.

Subjects
DNA, NANOPARTICLES, SCANNING electron microscopy, ATOMIC force microscopy, CRYSTALS, OXIDATION, NANOSTRUCTURED materials
Abstract

To examine the applicability of DNA-programmed self-assembly to preparation of nanoparticle-supported catalysts, the authors performed the arrangement control of Au nanoparticles on powder supports (TiO2 and glass) with this scheme. Scanning electron microscopy and atomic force microscopy observations confirmed that designed arrangement of two kinds of Au nanoparticles is possible on powder and crystal supports. Although catalytic activity of Au-particle/TiO2 systems for CO oxidation was almost inhibited by the presence of DNA, it was successfully recovered by the oxygen plasma treatment. These results indicate that the DNA-programmed self-assembly can be used as a preparation method of novel catalysts with designed nanostructures. [ABSTRACT FROM AUTHOR]

Published
2010
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35. beta 2-Glycoprotein I/HLA class II complexes are novel autoantigens in antiphospholipid syndrome

Author

Tanimura, K, Jin, H, Suenaga, T, Morikami, S, Arase, N, Kishida, K, Hirayasu, K, Kohyama, M, Ebina, Y, Yasuda, S, Horita, T, Takasugi, K, Ohmura, K, Yamamoto, K, Katayama, I, Sasazuki, T, Lanier, LL, Atsumi, T, Yamada, H, and Arase, H

Abstract

Antiphospholipid syndrome (APS) is an autoimmune disorder characterized by thrombosis and/or pregnancy complications. β2-glycoprotein I (β2GPI) complexed with phospholipid is recognized as a major target for autoantibodies in APS; however, less than half the patients with clinical manifestations of APS possess autoantibodies against the complexes. Therefore, the range of autoantigens involved in APS remains unclear. Recently, we found that human leukocyte antigen (HLA) class II molecules transport misfolded cellular proteins to the cell surface via association with their peptide-binding grooves. Furthermore, immunoglobulin G heavy chain/HLA class II complexes were specific targets for autoantibodies in rheumatoid arthritis. Here, we demonstrate that intact β2GPI, not peptide, forms a complex with HLA class II molecules. Strikingly, 100 (83.3%) of the 120 APS patients analyzed, including those whose antiphospholipid antibody titers were within normal range, possessed autoantibodies that recognize β2GPI/HLA class II complexes in the absence of phospholipids. In situ association between β2GPI and HLA class II was observed in placental tissues of APS patients but not in healthy controls. Furthermore, autoantibodies against β2GPI/HLA class II complexes mediated complement-dependent cytotoxicity against cells expressing the complexes. These data suggest that β2GPI/HLA class II complexes are a target in APS that might be involved in the pathogenesis.

Published
2015

38. FRI0345 Autoantibodies in Rheumatoid Arthritis Specifically Recognize Igg Heavy Chain Complexed with Hla-Dr, Which is Strongly Associated with Rheumatoid Arthritis Susceptibility

Author

Jin, H., primary, Arase, N., additional, Hirayasu, K., additional, Kohyama, M., additional, Suenaga, T., additional, Saito, F., additional, Tanimura, K., additional, Matsuoka, S., additional, Ebina, K., additional, Shi, K., additional, Yasuda, S., additional, Horita, T., additional, Hiwa, R., additional, Takasugi, K., additional, Ohmura, K., additional, Yoshikawa, H., additional, Saito, T., additional, Atsumi, T., additional, Sasazuki, T., additional, Katayama, I., additional, Lanier, L.L., additional, and Arase, H., additional

Published
2014
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41. Ab initio study of symmetric tilt boundaries in ZnO

Author

90378795, 70183861, Oba, F, Nishitani, SR, Adachi, H, Tanaka, I, Kohyama, M, Tanaka, S, 90378795, 70183861, Oba, F, Nishitani, SR, Adachi, H, Tanaka, I, Kohyama, M, and Tanaka, S

Published
2001

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