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165 results on '"Ueda, Hirokazu"'

11. Rearrangement of indene skeletons under mild conditions

Author

Kuninobu, Yoichiro, Ueda, Hirokazu, Kowata, Atsushi, and Takai, Kazuhiko

Subjects
Amino compounds -- Chemical properties, Radiation chemistry -- Research, Rearrangements (Chemistry) -- Analysis, Biological sciences, Chemistry
Abstract

The rearrangement of aminoindene derivatives that has proceeded even at room temperature without ultraviolet (UV) irradiation is presented. The results have shown that an amino group at the 3-position has played an important role to accelerate the rearrangement under mild conditions.

Published
2007

12. Activation of a novel transcription factor through phosphorylation by WIPK, a wound-induced mitogen-activated protein kinase in tobacco plants (1)

Author

Yap, Yun-Kiam, Kodama, Yutaka, Waller, Frank, Chung, Kwi Mi, Ueda, Hirokazu, Nakamura, Kimiyo, Oldsen, Maren, Yoda, Hiroshi, Yamaguchi, Yube, and Sano, Hiroshi

Subjects
Phosphorylation -- Research, Phosphorylation -- Physiological aspects, Genetic transcription -- Research, Tobacco (Plant) -- Research, Tobacco (Plant) -- Genetic aspects, Protein kinases -- Research, Plant physiology -- Research, Biological sciences, Science and technology
Published
2005

17. Delayed neuronal death in ischemic hippocampus involves stimulation of protein tyrosine phosphorylation

Author

Toshiho, Ohtsuki, Matsumoto, Masayasu, Kitagawa, Kazuo, Mabuchi, Takuma, Mandai, Kenji, Matsushita, Kohji, Kuwabara, Keisuke, Tagaya, Masafumi, Ogawa, Satoshi, Ueda, Hirokazu, Kamada, Takenobu, and Yanagihara, Takehiko

Subjects
Cerebral ischemia -- Physiological aspects, Protein tyrosine kinase -- Physiological aspects, Cell death -- Physiological aspects, Neurons -- Physiological aspects, Phosphorylation -- Physiological aspects, Cellular signal transduction -- Physiological aspects, Biological sciences
Abstract

Tyrosine kinase acts as a messenger of neuronal cell death during the selective degeneration of hippocampal pyramid cells in transient forebrain ischemia models. Protein tyrosine phosphorylation of pp42 was detected after the nonlethal and lethal ischemia of the hippocampus and cerebral cortex. The ischemic hippocampal CA1 neurons also exhibited increased expression of phosphotyrosyl proteins indicating the anti-microtubule-associated protein kinase activity of pp42.

Published
1996

19. Mechanisms for Graphene Growth on SiO2Using Plasma-Enhanced Chemical Vapor Deposition: A Density Functional Theory Study

Author

Longo, Roberto C., Ueda, Hirokazu, Cho, Kyeongjae, Ranjan, Alok, and Ventzek, Peter L. G.

Abstract

Plasma-enhanced chemical vapor deposition (PE-CVD) of graphene layers on dielectric substrates is one of the most important processes for the incorporation of graphene in semiconductor devices. Graphene is moving rapidly from the laboratory to practical implementation; therefore, devices may take advantage of the unique properties of such nanomaterial. Conventional approaches rely on pattern transfers after growing graphene on transition metals, which can cause nonuniformities, poor adherence, or other defects. Direct growth of graphene layers on the substrates of interest, mostly dielectrics, is the most logical approach, although it is not free from challenges and obstacles such as obtaining a specific yield of graphene layers with desired properties or accurate control of the growing number of layers. In this work, we use density-functional theory (DFT) coupled with ab initio molecular dynamics (AIMD) to investigate the initial stages of graphene growth on silicon oxide. We select C2H2as the PE-CVD precursor due to its large carbon contribution. On the basis of our simulation results for various surface models and precursor doses, we accurately describe the early stages of graphene growth, from the formation of carbon dimer rows to the critical length required to undergo dynamical folding that results in the formation of low-order polygonal shapes. The differences in bonding with the functionalization of the silicon oxide also mark the nature of the growing carbon layers as well as shed light of potential flaws in the adherence to the substrate. Finally, our dynamical matrix calculations and the obtained infrared (IR) spectra and vibrational characteristics provide accurate recipes to trace experimentally the growth mechanisms described and the corresponding identification of possible stacking faults or defects in the emerging graphene layers.

Published
2022
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28. Accumulation of salicylic acid in tomato plant under biological stress affects oviposition preference of Bemisia tabaci.

Author

Ueda, Hirokazu, Kugimiya, Soichi, Tabata, Jun, Kitamoto, Hiroko, and Mitsuhara, Ichiro

Subjects
*SWEETPOTATO whitefly, *SALICYLIC acid, *TOBACCO mosaic virus, *TOMATO diseases & pests, *BIOACCUMULATION, *INSECT pests, *TOMATO varieties
Abstract

In field, plants are exposed to multiple biological stresses simultaneously; for example, insect damage and pathogenic virus infection. In this study, we constructed a simple tripartite experimental system using tomato plant, their insect pest Bemisia tabaci (whitefly), and infectious tomato mosaic virus (ToMV). In the choice test, whiteflies laid more eggs on uninfected plant than on ToMV-infected plant. Further, whiteflies hatched more and grew better on the uninfected plant. Salicylic acid (SA) accumulated in infected plants, and the expression of genes involved in SA production and SA-related response was significantly induced. These plant responses against ToMV infection were similar to those against whitefly attack or SA-treated plants. To examine the importance of plant endogenous SA for whitefly preference, we repeated the choice test using the NahG transgenic tomato that cannot accumulate SA. Whiteflies did not show oviposition preference between NahG plants with and without ToMV infection or whitefly infestation. Overall, whiteflies prefer healthy plants, and SA accumulation in response to biological stresses is involved in their preference. [ABSTRACT FROM AUTHOR]

Published
2019
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34. High Performance Normally-off GaN MOSFETs on Si Substrates

Author

Kambayashi, Hiroshi, primary, Ikeda, Nariaki, additional, Nomura, Takehiko, additional, Ueda, Hirokazu, additional, Morozumi, Y., additional, Harada, Katsushige, additional, Hasebe, Kazuhide, additional, Teramoto, Akinobu, additional, Sugawa, Shigetoshi, additional, and Ohmi, Tadahiro, additional

Published
2013
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