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排序方式: 共有188条查询结果,搜索用时 828 毫秒
111.
Takahiro Tsutsui Shunsuke Kusaba Dr. Masahiro Yamashina Prof. Dr. Munetaka Akita Dr. Michito Yoshizawa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(17):4320-4324
Host functions of polyaromatic nanocavities were revealed by using an M2L4 molecular cage and capsule. On the basis of the previously reported M2L4 capsule with a closed polyaromatic cavity, a new M2L4 cage (as a mixture of the isomers) was prepared by the quantitative assembly of two metal ions and four desymmetrized bispyridine ligands with a single polyaromatic panel. The obtained, open nanocavity of the cage exhibited enhanced binding abilities toward large dyes and pigments in water. For example, two molecules of coumarin dyes were bound in the nanocavity and showed strong whitish emission (up to ΦF=34 %). Furthermore, metallopigments, the sizes of which are larger than the inner cavities of the cage and capsule, were bound only in the open polyaromatic nanocavity of the cage to give water-soluble 1:1 host–guest complexes. 相似文献
112.
Yuya Tsutsui Dr. Daiki Tanaka Dr. Yoshiyuki Manabe Yuka Ikinaga Kumpei Yano Prof. Dr. Koichi Fukase Dr. Akihito Konishi Prof. Dr. Makoto Yasuda 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(62):e202202284
We describe the synthesis and characterization of a photoactivated boron-based Lewis acid catalyst based on a cage-shaped triphenolic ligand with three pyrenylmethyl moieties. The obtained cage-shaped borate functioned as a photoactivated Lewis acid catalyst thanks to the flexible three pyrenylmethyl moieties. The deformation of the cage-shaped scaffold driven by intramolecular excimer formations of the pyrenes is a critical factor in realizing the photoactivation. Mannich-type reactions and glycosylations significantly were accelerated under 370 nm light irradiations. It is noteworthy that various glycosyl fluorides, which are not easily activated in photocatalytic systems due to their high C−F bond stability, are activated by the photoimproved catalytic activity of the catalyst. 相似文献
113.
Ariaki Murata Kenji Kai Ken Tsutsui Jun Takeuchi Yasushi Todoroki Kazuo Furihata Mineyuki Yokoyama Susanne Baldermann Naoharu Watanabe 《Tetrahedron》2012,68(27-28):5583-5589
Plant oxylipins are an important class of signaling molecules in plants. The cyclic adducts of epinephrine or norepinephrine with the naturally occurring oxylipin (12Z,15Z)-9-hydroxy-10-oxo-octadeca-12,15-dienoic acid (KODA, 1) or its synthetic analogues (2–6) have been reported to possess flower-inducing activity toward Lemna paucicostata. By in vivo and in vitro experiments with seedlings of Pharbitis nil cv. Violet carbonyl groups of the α-ketols (1 and 3) and the ketones (7 and 9) were enantio-selectively reduced to give their corresponding vicinal diols (2 and 4) and alcohols (8 and 10). The stereo-chemistry at the oxymethine carbon was determined based on the long range C–H coupling constants and the modified Mosher's method. Orientation of the adjacent hydroxyl group in (1 and 3) did not affect the enantio-selectivity, whereas the conversion was slightly affected and higher yields were obtained with the R-enantiomers of the α-ketols. 相似文献
114.
Electrical detection of single pollen allergen particles using electrode-embedded microchannels 总被引:1,自引:0,他引:1
We report on the development of a microfluidic system for the electrical detection of single pollen allergen particles. Our device consists of 500 nm electrode gaps fabricated in an 800 nm wide fluidic channel. We flowed pollen allergen particles of average size 330 nm along the channel via fluid pumping and simultaneously monitored temporal change in dc current flowing through the sensing electrodes. Current spikes were detected, which can be attributed to a capacitance discharging upon trapping/detrapping of single allergens in the electrode gap. This sensing mechanism may open new avenues for a highly sensitive pollen allergen sensor. 相似文献
115.
W. Tsutsui T. Siegmund N. D. Parab H. Liao T. N. Nguyen W. Chen 《Experimental Mechanics》2018,58(4):627-632
The state-of-charge and deformation-rate dependent mechanical behavior of cylindrical lithium-ion battery cells was investigated. The research revealed that both state of charge and deformation rates affected the stiffness of the battery cells. Battery mechanical failure load was only weakly dependent on the state of charge. For the deformation-rate dependency on the mechanical integrity of battery cells, the battery mechanical failure load was either decreased significantly at high state of charge or decreased slightly at low state of charge as deformation rate increased. For the correlation between mechanical integrity and electrical failure, the displacement at the battery mechanical failure load coincided with a voltage drop. However, at high state of charge, premature and incomplete voltage drops were observed before the definite final voltage drop. No such premature voltage drop was observed in low state-of-charge specimens. The results of this research may be used as a reference for the design of impact and damage tolerant electric vehicle battery systems. 相似文献
116.
Yoshio Muguruma Haruhito Tsutsui Hiroyasu Akatsu Koichi Inoue 《Biomedical chromatography : BMC》2020,34(2):e4722
The metabolome presence of nucleobases, nucleosides, nucleotides and related phosphorylated metabolites has been examined for Alzheimer's disease (AD). Although reversed-phase liquid chromatography tandem mass spectrometry (LC–MS/MS) has been used for the determination of these analytes, they were limited in chromatographic signal intensity and reproducibility owing to significant peak tailing caused by complexing with metallic cations and phosphate groups. In this work, we applied LC–MS/MS analysis with a metal-free column for comprehensive quantification of 40 analytes regarding to purine and pyrimidine metabolism in postmortem cerebrospinal fluid (pCSF) from AD patients. For the analytical column, an InertSustain AQ-C18 metal-free PEEK column was used. MS detection was by electrospray positive ionization. The metal-free column allowed for sharp peak detection of highly polar metabolites within a running time of 17 min. In validation, the limits of detection (LOD), the limit of quantitation (LOQ) and recovery value using a pooled pCSF sample are 1–500 nM, 0.5–250 nM and a range of 53.1–144.0% (RSD ranged from 0.4 to 19.6%). The developed LC–MS/MS method utilizing a metal-free column provides an accurate quantification of some metabolites regarding purine and pyrimidine metabolism in pCSF samples obtained from AD patients. 相似文献
117.
Keita Niki Takahiro Tsutsui Masahiro Yamashina Munetaka Akita Michito Yoshizawa 《Angewandte Chemie (International ed. in English)》2020,59(26):10489-10492
Selective recognition of natural fatty acids is intrinsically difficult owing to the long, flexible, and poorly interactive hydrocarbon chains. Inspired by biological recognition systems, we herein demonstrate the exclusive binding of a monounsaturated fatty acid by an artificial polyaromatic receptor from a mixture of the unsaturated and corresponding saturated substrates (i.e., oleic and stearic acids) in water. The selectivity stems from multiple CH–π/π–π interactions between the host framework and the guest in its roughly coiled conformation. Moreover, competitive binding experiments elucidate higher binding affinities of the receptor for oligo‐ and polyunsaturated fatty acids (e.g., α‐linolenic acid and EPA). Within the receptor, the biosubstrates are remarkably stabilized against air, light, and heat owing to the polyaromatic shielding effect. 相似文献
118.
Jinxuan Liu Wencai Zhou Jianxi Liu Ian Howard Goran Kilibarda Sabine Schlabach Damien Coupry Matthew Addicoat Satoru Yoneda Yusuke Tsutsui Tsuneaki Sakurai Shu Seki Zhengbang Wang Peter Lindemann Engelbert Redel Thomas Heine Christof Wll 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(25):7549-7553
119.
Hiroki IwasakiNozomi Tsutsui Toru EguchiHiroaki Ohno Masayuki Yamashita Tetsuaki Tanaka 《Tetrahedron letters》2011,52(15):1770-1772
We report a samarium(II)-mediated tandem spirocyclization reaction to provide dispiro[4.2.4.2]tetradecadiene and dispiro[4.2.5.2]pentadecadiene skeletons. The reaction was achieved by intramolecular addition of a ketyl radical onto an aromatic ring bearing an electrophilic moiety followed by reductive capture of the spirohexadienyl radical intermediate with SmI2 in the presence of HMPA. 相似文献
120.
M. Inui Y. Kajihara K. Matsuda S. Hosokawa K. Tamura M. Yao Y. Tsuchiya D. Ishikawa S. Tsutsui A. Q. R. Baron 《The European physical journal. Special topics》2011,196(1):167-174
Liquid As2Se3 undergoes the semiconductor-metal transition with increasing temperature when pressure is applied to avoid evaporation of
the liquid. To investigate the atomic dynamics of liquid As2Se3, we have carried out inelastic x-ray scattering experiments of this system at 1073 K and 6 MPa and obtained the dynamic structure
factor S(Q,E), from approximately 1.6 nm−1 to 11 nm−1, where Q and E are momentum and energy transfer, respectively. The excitation energy in the semiconducting state at 1073 K disperses as
fast as the ultrasonic sound velocity at Q < 2.5 nm−1 but at Q > 2.9 nm−1 it disperses approximately 1.8 times faster. We analyzed S(Q,E) at 1073 K using a simple viscoelastic model and discussed Q dependence of the propagation of the acoustic mode. 相似文献