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排序方式: 共有727条查询结果,搜索用时 31 毫秒
581.
Yugo Kuriki Takafusa Yoshioka Mako Kamiya Toru Komatsu Hiroyuki Takamaru Kyohhei Fujita Hirohisa Iwaki Aika Nanjo Yuki Akagi Kohei Takeshita Haruaki Hino Rumi Hino Ryosuke Kojima Tasuku Ueno Kenjiro Hanaoka Seiichiro Abe Yutaka Saito Jun Nakajima Yasuteru Urano 《Chemical science》2022,13(16):4474
Fluorescent probes that can selectively detect tumour lesions have great potential for fluorescence imaging-guided surgery. Here, we established a library-based approach for efficient screening of probes for tumour-selective imaging based on discovery of biomarker enzymes. We constructed a combinatorial fluorescent probe library for aminopeptidases and proteases, which is composed of 380 probes with various substrate moieties. Using this probe library, we performed lysate-based in vitro screening and/or direct imaging-based ex vivo screening of freshly resected clinical specimens from lung or gastric cancer patients, and found promising probes for tumour-selective visualization. Further, we identified two target enzymes as novel biomarker enzymes for discriminating between tumour and non-tumour tissues. This library-based approach is expected to be an efficient tool to develop tumour-imaging probes and to discover new biomarker enzyme activities for various tumours and other diseases.Efficient methodology to develop tumor-imaging fluorescent probes based on screening with our newly constructed probe library for aminopeptidase/protease (380 probes) and clinical samples has been established. 相似文献
582.
Platinum-catalyzed intramolecular hydrosilation of hydrodimethylsilyl ethers of homopropargyl alcohols proceeds regioselectively in a 5-exo-dig mode. The resulting vinylsilanes can be transformed into 3-alkanon-1-ol and 3-bromo-3-alken-1-ol derivatives by H2O2 oxidation and bromine cleavage, respectively. 相似文献
583.
584.
Kohei Tamao Takahisa Iwahara Ryuichiro Kanatani Makoto Kumada 《Tetrahedron letters》1984,25(18):1909-1912
Carbanions α to (alkoxy)silyl or (amino)silyl groups act as nucleophilic α-hydroxy-alkylating agents for organic halides and epoxides via the metal catalyzed coupling reaction and the subsequent oxidative cleavage of the carbon-silicon bond. 相似文献
585.
Shinichiro Kitayama Kohei Sanui Naoya Ogata 《Journal of polymer science. Part A, Polymer chemistry》1984,22(10):2705-2712
Aromatic polyesters of high molecular weights were prepared by the direct polycondensation reaction of dicarboxylic acids and bisphenols or hydroxybenzoic acids with triphenylphosphine dichloride as a new condensing agent. Reaction conditions, including the amount of reagents and the concentration of monomer, solvent, and acid acceptor, were investigated. The aromatic polyester with the solution viscosity of 1.66 dL/g was obtained from bisphenol. A and terephthalic and isophthalic acid in quantitative yield under the optimum condition. The principal advantage of this condensing agent is that, based on the recycling system, recovered triphenylphosphine oxide can be reconverted to the reactive triphenylphosphine dichloride by treating with phosgene or oxalyl chloride. 相似文献
586.
Yukinobu Takahashi Yu Hashimoto Kohei Saito Toshiyuki Takayanagi 《Molecules (Basel, Switzerland)》2021,26(23)
The dissociative photodetachment dynamics of the oxalate anion, C2O4H− + hν → CO2 + HOCO + e−, were theoretically studied using the on-the-fly path-integral and ring-polymer molecular dynamics methods, which can account for nuclear quantum effects at the density-functional theory level in order to compare with the recent experimental study using photoelectron–photofragment coincidence spectroscopy. To reduce computational time, the force acting on each bead of ring-polymer was approximately calculated from the first and second derivatives of the potential energy at the centroid position of the nuclei beads. We find that the calculated photoelectron spectrum qualitatively reproduces the experimental spectrum and that nuclear quantum effects are playing a role in determining spectral widths. The calculated coincidence spectrum is found to reasonably reproduce the experimental spectrum, indicating that a relatively large energy is partitioned into the relative kinetic energy between the CO2 and HOCO fragments. This is because photodetachment of the parent anion leads to Franck–Condon transition to the repulsive region of the neutral potential energy surface. We also find that the dissociation dynamics are slightly different between the two isomers of the C2O4H− anion with closed- and open-form structures. 相似文献
587.
588.
Toshihiro Otsuki Kohei Goto Zen Komiya 《Journal of polymer science. Part A, Polymer chemistry》2000,38(Z1):4661-4668
New hydrogenated ring‐opening metathesis polymers with excellent thermal and optical properties were developed. These polymers were prepared by the ring‐opening metathesis polymerization of ester‐substituted tetracyclododecene monomers followed by the hydrogenation of the main‐chain double bond. The degree of hydrogenation was an important factor for the thermal stability of the polymers, and as complete hydrogenation as possible was necessary to obtain a thermally stable polymer. The completely hydrogenated ring‐opening polymer derived from 8‐methyl‐8‐methoxycarbonyl‐substituted monomer has a glass‐transition temperature of 171 °C and a 5% weight‐loss temperature of 446 °C. This polymer has excellent thermal and optical properties because of its bulky and unsymmetrical polycyclic structure in the main chain and is an alternative to glass or other transparent polymers such as poly(methyl methacrylate) and polycarbonate resin. This polymer has also been used in a wide variety of applications, such as optical lenses, optical disks, optical films, and optical fiber. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4661–4668, 2000 相似文献
589.
Silver was introduced into soda-lime silicate glass by a classical staining process under varying conditions of temperature and time. The spectroscopic features of the stained glasses were investigated by studying absorption, photoluminescence and electron paramagnetic resonance properties. The diffusion parameters (diffusion coefficient and diffusion activation energy) of silver ions were calculated based on elemental analysis data from inductively coupled plasma (ICP) spectrometry, and line scan profiles from energy dispersion X-ray analysis (EDX). 相似文献
590.
Ayato Arai Prof. Hisahiro Sasabe Kohei Nakao Yuki Masuda Prof. Junji Kido 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(15):4971-4976
High-performance organic light-emitting diodes (OLEDs) that use phosphorescent and/or thermally activated delayed fluorescence emitters are capable of realizing 100 % electron-to-photon conversion. The host materials in these OLEDs play crucial roles in determining OLED performance. Carbazole derivatives are frequently used as host materials, among which 3,3-bis(9H-carbazol-9-yl)biphenyl ( mCBP ) is often used for lifetime testing in scientific studies. In this study, the π conjugation of the carbazole unit was expanded to enhance OLED lifetime by designing and developing two benzothienocarbazole (BTCz)-based host materials, namely m1BTCBP and m4BTCBP . Among these host materials, m1BTCBP formed a highly efficient [Ir(ppy)3]-based OLED with an operational luminescence half-life (LT50) of over 300 h at an initial luminance of approximately 12000 cd m−2 (current density: 25 mA cm−2). The LT50 value at 1000 cd cm−2 was estimated to be about 23 000 h. This performance is clearly higher than that of mCBP -based OLEDs (LT50≈8500 h). 相似文献