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排序方式: 共有933条查询结果,搜索用时 31 毫秒
921.
Ryo Yasuhara Toshiyuki Kawashima Takashi Sekine Takashi Kurita Tadashi Ikegawa Osamu Matsumoto Masahiro Miyamoto Hirofumi Kan Hidetsugu Yoshida Junji Kawanaka Masahiro Nakatsuka Noriaki Miyanaga Yasukazu Izawa Tadashi Kanabe 《Optics letters》2008,33(15):1711-1713
We report a high-average-power and high-pulse-energy diode-pumped Nd:glass laser amplifier system consisting of two thermally-edge-controlled zigzag slab amplifiers and a stimulated Brillouin scattering mirror. This phase-conjugated system produces an average power of 213 W at 10 Hz in a 8.9 ns pulse (2.4 GW peak power) with an optical-to-optical conversion efficiency of 11.7% and a near-diffraction-limited beam. To the best of our knowledge, this is the highest performance from a Nd:glass-based laser amplifier system ever built. 相似文献
922.
Toshikazu NAKAMURA Shinya MIZUNO 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2010,86(6):588-610
It has been more than 25 years since HGF was discovered as a mitogen of hepatocytes. HGF is produced by stromal cells, and stimulates epithelial cell proliferation, motility, morphogenesis and angiogenesis in various organs via tyrosine phosphorylation of its receptor, c-Met. In fetal stages, HGF-neutralization, or c-Met gene destruction, leads to hypoplasia of many organs, indicating that HGF signals are essential for organ development. Endogenous HGF is required for self-repair of injured livers, kidneys, lungs and so on. In addition, HGF exerts protective effects on epithelial and non-epithelial organs (including the heart and brain) via anti-apoptotic and anti-inflammatory signals. During organ diseases, plasma HGF levels significantly increased, while anti-HGF antibody infusion accelerated tissue destruction in rodents. Thus, endogenous HGF is required for minimization of diseases, while insufficient production of HGF leads to organ failure. This is the reason why HGF supplementation produces therapeutic outcomes under pathological conditions. Moreover, emerging studies delineated key roles of HGF during tumor metastasis, while HGF-antagonism leads to anti-tumor outcomes. Taken together, HGF-based molecules, including HGF-variants, HGF-fragments and c-Met-binders are available as regenerative or anti-tumor drugs. Molecular analysis of the HGF-c-Met system could provide bridges between basic biology and clinical medicine. 相似文献
923.
Takashi Ikeda Dr. Keishiro Tahara Dr. Ryoichi Ishimatsu Prof. Toshikazu Ono Dr. Luxia Cui Momoka Maeda Prof. Yoshiki Ozawa Prof. Masaaki Abe 《Angewandte Chemie (International ed. in English)》2023,62(21):e202301109
This study reports an effective peripheral decoration of organic donor-acceptor diads with B(C6F5)3 for stabilizing electrogenerated radical ions. By employing a common p-type organic semiconductor benzothienobenzothiophene (BTBT) as the donor, tetracoordinate boron complexes showed improved solution electrochemiluminescence (ECL) intensity, reaching a 156-fold increase compared to that of the parent diad. The unprecedented Lewis-pairing-induced ECL enhancement is attributed to the multiple roles of B(C6F5)3: 1) redistributing frontier orbitals, 2) facilitating electrochemical excitation, and 3) restricting molecular motions. Furthermore, B(C6F5)3 converted the molecular arrangement of BTBT from conventional 2D herringbones into 1D π-stacks. This robust, highly ordered columnar nanostructure allowed red-shifting of the crystalline film ECL with electrochemical doping through the electronic coupling pathways of BTBT. Our approach will facilitate the development of elaborate metal-free ECL systems. 相似文献
924.
Toshikazu Hirao 《Macromolecular Symposia》2002,186(1):75-80
A combination of transition metals and π-conjugated molecules or polymers as redox-active ligands affords the hybrid conjugated complexes. A variety of structural design is possible based on the coordination number and geometry to construct an efficient multi-redox system. 相似文献
925.
926.
Prof. Dr. Toshikazu Takata Prof. Dr. Koji Yamamoto Kazuki Higuchi Dr. Masahiro Ogawa Ayumi Kawasaki Shunya Mizuno Hikaru Iwasaki Masaki Nagashima Prof. Dr. Yoshihiro Hayashi Prof. Dr. Susumu Kawauchi Prof. Dr. Kazuko Nakazono Prof. Dr. Yasuhito Koyama 《Angewandte Chemie (International ed. in English)》2023,62(24):e202303494
Post-synthesis modification of polymers streamlines the synthesis of functionalized polymers, but is often incomplete due to the negative polymer effects. Developing efficient polymer reactions in artificial systems thus represents a long-standing objective in the fields of polymer and material science. Here, we show unprecedented macrocycle-metal-complex-catalyzed systems for efficient polymer reaction that result in 100 % transformation of the main chain functional groups presumably via a processive mode reaction. The complete polymer reactions were confirmed in not only intramolecular reaction (hydroamination) but also intermolecular reaction (hydrosilylation) by using Pd- and Pt-macrocycle-catalyzed systems. The most fascinating feature of the both reactions is that higher-molecular-weight polymers reach completion faster. Various studies suggested that the reactions occur in the catalyst cavity via the formation of a supramolecular complex between the macrocycle catalyst and polymer substrate like pseudorotaxane, which should be of characteristic of the efficient polymer reactions progressing in a processive mode. 相似文献
927.
Dr. Yosuke Akae Prof. Dr. Toshikazu Takata 《European journal of organic chemistry》2023,26(12):e202300171
The acylation of a cyclodextrin-based [3]rotaxane was implemented with anhydride reagents following a facile procedure. Methacrylic anhydride facilitated the introduction of a vinyl-group into the rotaxane structure toward achieving a crosslinker. Interestingly, only a few methacrylic units were attached to the cyclodextrin at reaction temperatures of up to 60 °C even with an excess amount of the reagent, probably due to steric hindrance. Therefore, the number of vinyl groups on the [3]rotaxane framework was easily controlled to be approximately two units via a simple random acylation, which worked effectively as a facile synthesis route for the rotaxane crosslinker. The acylation behavior was investigated in detail by NMR and MALDI-TOF-MS analyses. Such a proposed approach will help overcome the trade-off between convenience and utility associated with the mono-modification of cyclodextrins. 相似文献
928.
Dr. Yu Zhao Dr. Saikat Das Taishu Sekine Haruna Mabuchi Tsukasa Irie Jin Sakai Dan Wen Prof. Weidong Zhu Prof. Teng Ben Prof. Yuichi Negishi 《Angewandte Chemie (International ed. in English)》2023,62(13):e202300172
The unique structural characteristics of three-dimensional (3D) covalent organic frameworks (COFs) like high surface areas, interconnected pore system and readily accessible active sites render them promising platforms for a wide set of functional applications. Albeit promising, the reticular construction of 3D COFs with large pores is a very demanding task owing to the formation of interpenetrated frameworks. Herein we report the designed synthesis of a 3D non-interpenetrated stp net COF, namely TUS-64, with the largest pore size of all 3D COFs (47 Å) and record-low density (0.106 g cm−3) by reticulating a 6-connected triptycene-based linker with a 4-connected porphyrin-based linker. Characterized with a highly interconnected mesoporous scaffold and good stability, TUS-64 shows efficient drug loading and controlled release for five different drugs in simulated body fluid environment, demonstrating the competency of TUS-64 as drug nanocarriers. 相似文献
929.
Akiya Ogawa Noriaki Takami Masahito Sekiguchi Noboru Sonoda Toshikazu Hirao 《Heteroatom Chemistry》1998,9(6):581-584
Elemental sulfur can be reduced to the corresponding thiolate anion species (S2− and S2−2) selectively by samarium diiodide in the presence and absence of HMPA, respectively. The subsequent alkylation of the thiolate anion species provides a useful synthetic route to dialkyl sulfides and disulfides. © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9: 581–584, 1998 相似文献
930.