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285 results on '"OIDA, S."'

1. Medium Energy Ion Scattering of Gr on SiC(0001) and Si(100)

Author

Copel, M., Oida, S., Kasry, A., Bol, A. A., Hannon, J. B., and Tromp, R. M.

Subjects
Condensed Matter - Materials Science
Abstract

Depth profiling of graphene with high-resolution ion beam analysis is a practical method for analysis of monolayer thicknesses of graphene. Not only is the energy resolution sufficient to resolve graphene from underlying SiC, but by use of isotope labeling it is possible to tag graphene generated from reacted ethylene. Furthermore, we are able to analyze graphene supported by oxidized Si(100) substrates, allowing the study of graphene films grown by chemical vapor deposition on metal and transfered to silicon. This introduces a powerful method to explore the fundamentals of graphene formation.

Published
2011
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2. Decoupling Graphene from SiC(0001) via Oxidation

Author

Oida, S., McFeely, F. R., Hannon, J. B., Tromp, R. M., Copel, M., Chen, Z., Sun, Y., Farmer, D. B., and Yurkas, J.

Subjects
Condensed Matter - Materials Science
Abstract

When epitaxial graphene layers are formed on SiC(0001), the first carbon layer (known as the "buffer layer"), while relatively easy to synthesize, does not have the desirable electrical properties of graphene. The conductivity is poor due to a disruption of the graphene pi-bands by covalent bonding to the SiC substrate. Here we show that it is possible to restore the graphene pi-bands by inserting a thin oxide layer between the buffer layer and SiC substrate using a low temperature, CMOS-compatible process that does not damage the graphene layer.

Published
2010
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16. X-ray photoelectron spectroscopy study on Fe and Co catalysts during the first stages of ethanol chemical vapor deposition for single-walled carbon nanotube growth

Author

Oida, S., McFeely, F.R., Bol, A.A., Oida, S., McFeely, F.R., and Bol, A.A.

Abstract

Optimized chemical vapor deposition processes for single-walled carbon nanotube (SWCNT) can lead to the growth of dense, vertically aligned, mm-long forests of SWCNTs. Precise control of the growth process is however still difficult, mainly because of poor understanding of the interplay between catalyst, substrate and reaction gas. In this paper we use x-ray photoelectron spectroscopy (XPS) to study the interplay between Fe or Co catalysts, SiO2 and Al2O3 substrates and ethanol during the first stages of SWCNT forest growth. With XPS we observe that ethanol oxidizes Fe catalysts at carbon nanotube (CNT) growth temperatures, which leads to reduced carbon nanotube growth. Ethanol needs to be decomposed by a hot filament or other technique to create a reducing atmosphere and reactive carbon species in order to grow vertically aligned single-walled carbon nanotubes from Fe catalysts. Furthermore, we show that Al2O3, unlike SiO2, plays an active role in CNT growth using ethanol CVD. From our study we conclude that metallic Fe on Al2O3 is the most optimal catalyst/substrate combination for high-yield SWCNT forest growth, using hot filament CVD with ethanol as the carbon containing gas.

Published
2011

18. Enamel matrix derivative gel stimulates signal transduction of BMP and TGF-{beta}.

Author

Suzuki S, Nagano T, Yamakoshi Y, Gomi K, Arai T, Fukae M, Katagiri T, Oida S, Suzuki, S, Nagano, T, Yamakoshi, Y, Gomi, K, Arai, T, Fukae, M, Katagiri, T, and Oida, S

Abstract

It has been shown that Emdogain Gel (Emd-Gel) containing enamel matrix proteins promotes biomineralization, such as osteogenesis and cementogenesis, during the regeneration of periodontal tissues. However, the growth factors involved in these activities of Emd-Gel remain unclear. In this study, Emd-Gel was fractionated into 22 sub-fractions by size exclusion chromatography. The osteoinductive factors, TGF-beta and BMP, were examined by a specific luciferase reporter gene assay. In the unfractionated Emd-Gel, TGF-beta-like activity was detected, while BMP activity was not. In contrast, in the fractionated Emd-Gel samples, TGF-beta-like activity was detected from fractions 8 to 13, and BMP-like activity was detected from fractions 4 to 6. Also, it was confirmed that the BMP-like activity in Emd-Gel was inhibited by authentic TGF-beta1 and TGF-beta-like activity. These results indicate that Emd-Gel contains both TGF-beta- and BMP-like growth factors that contribute to the induction of biomineralization during periodontal regeneration. [ABSTRACT FROM AUTHOR]

Published
2005
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19. Periostin of human periodontal ligament fibroblasts promotes migration of human mesenchymal stem cell through the αvβ3 integrin/ FAK/ PI3 K/ Akt pathway.

Author

Matsuzawa, M., Arai, C., Nomura, Y., Murata, T., Yamakoshi, Y., Oida, S., Hanada, N., and Nakamura, Y.

Subjects
ACADEMIC medical centers, ANALYSIS of variance, CELL culture, CELLULAR signal transduction, PERIODONTAL ligament, POLYMERASE chain reaction, RESEARCH funding, STATISTICS, STEM cells, WESTERN immunoblotting, DATA analysis, REVERSE transcriptase polymerase chain reaction, DATA analysis software, IN vitro studies
Abstract

Background and Objective The periodontal ligament ( PDL) is characterized by rapid turnover, high remodeling capacity and high inherent regenerative potential compared with other connective tissues. Periostin, which is highly expressed in the fibroblasts in the PDL, has been widely discussed in relation to collagen fibrillogenesis in the PDL. Recently, several reports have indicated periostin in cell migration. The aim of this study was to examine whether human PDL fibroblasts ( hPDLFs) with high levels of periostin expression promote the migration of human bone marrow mesenchymal stem cells ( hMSCs). Material and Methods The migration of hMSCs was examined by transwell chamber migration assay under different conditions: medium alone, hPDLFs, human dermal fibroblasts, recombinant periostin, integrin αvβ3 blocking antibody (anti- CD51/61 antibody) and inhibitors of FAK ( PF431396) and PI3 K ( LY294002). Phosphorylation of FAK and Akt in hMSCs under stimulation of periostin was examined by western blotting. Results The migration assay revealed that the number of migrated hMSCs by hPDLFs was significantly larger than those by dermal fibroblasts, periostin small interfering RNA hPDLFs and medium alone. Furthermore, recombinant periostin also strongly induced hMSC migration. The addition of anti- CD51/61 antibody, PF431396 and LY294002 caused a significant reduction in the number of migrated hMSCs respectively. The anti- CD51/61 antibody inhibited both FAK and Akt phosphorylations under periostin stimulation. PF431396 inhibited both FAK and Akt phosphorylations. LY294002 inhibited only Akt phosphorylation, and FAK phosphorylation was not influenced under periostin stimulation. Conclusion Periostin expression in hPDLFs promotes the migration of hMSCs through the αvβ3 integrin/ FAK/ PI3 K/ Akt pathway in vitro. [ABSTRACT FROM AUTHOR]

Published
2015
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