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排序方式: 共有614条查询结果,搜索用时 15 毫秒
51.
52.
Straub PB Jaffe DE Glass HD Adams MR Brown CN Charpak G Cooper WE Crittenden JA Finley DA Gray R Hemmi Y Hsiung YB Hubbard JR Jonckheere AM Jöstlein H Kaplan DM Lederman LM Luk KB Maki A Mangeot P McCarthy RL Miyake K Plaag RE Rutherfoord JP Sakai Y Santiard JC Sauli F Smith SR Yoshida T Young KK 《Physical review letters》1992,68(4):452-455
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Tunable diode laser spectra have been measured for the ν4 band of cis-HONO near 850 cm?1 and the ν2 band of rans-HONO near 1700 cm?1. The ν4 band is completely unperturbed and 355 well-resolved transitions have been fit with a standard deviation of 0.0007 cm?1. The ν2 band appears to have some small perturbations, but about 190 transitions have been fit with a standard deviation of 0.0027 cm?1. Rotational and centrifugal distortion constants are given for both bands. 相似文献
55.
Duanyang Wang Maki Nagata Masako Matsumoto Yhiya Amen Dongmei Wang Kuniyoshi Shimizu 《Molecules (Basel, Switzerland)》2022,27(18)
Hibiscus sabdariffa L. (HS) has a long history of edible and medicinal uses. In this study, the biological activities of the extracts, chromatographic fractions, and hibiscus acid obtained from HS were evaluated for their potential bioactivities. Their ability to promote extracellular matrix synthesis in skin fibroblasts was evaluated by enzyme-linked immunosorbent assays. Their anti-inflammatory activity was evaluated in a nitric oxide (NO)–Griess inflammatory experiment. Furthermore, hibiscus acid was found to have a strong anti-oxidative stress effect through the establishment of an oxidative stress model induced by hydrogen peroxide. Several assays indicated that hibiscus acid treatment can effectively reduce extracellular adenosine triphosphate (ATP) secretion and carbonyl protein production, as well as maintain a high level of reduced/oxidized glutathione (GSH/GSSG) in skin cells, thus providing a possible mechanism by which hibiscus acid can counter antioxidative stress. The present study is the first to explore the reversing skin aging potential and the contributory component of HS. 相似文献
56.
Maki Sachiko Eiji Nishibori Shinobu Aoyagi Makoto Sakata Masaki Takata Mio Kondo Masaki Murata Ryota Sakamoto Hiroshi Nishihara 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(7):696-703
The title compound, [Fe2(C5H5)2(C40H22O2)] or 1,4‐(FcPh)2Aq [where FcPh is 2‐(4‐ferrocenylphenyl)ethynyl and Aq is anthraquinone], was synthesized in an attempt to obtain a new solvent‐incorporating porous material with a large void space. Thermodynamic data for 1,4‐(FcPh)2Aq show a phase transition at approximately 430 K. The crystal structure of solvent‐free 1,4‐(FcPh)2Aq was determined at temperatures of 90, 300 and 500 K using synchrotron powder diffraction data. A direct‐space method using a genetic algorithm was employed for structure solution. Charge densities calculated from observed structure factors by the maximum entropy method were employed for model improvement. The final models were obtained through multistage Rietveld refinements. In both phases, the structures of which differ only subtly, the planar Aq fragments are stacked alternately in opposite orientations, forming a one‐dimensional column. The FcPh arms lie between the stacks and fill the remaining space, leaving no voids. C—H...π interactions between the Ph and Fc fragments mediate crystal packing and stabilization. 相似文献
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Hiroyuki Ishibashi Iwao Takamuro Yo-Ichi Mizukami Maki Irie Masazumi Ikeda 《合成通讯》2013,43(3-4):443-452
Friedel-Crafts acylation of arenes with methylthio- (1) or phenylthio-acetyl chloride (2) provides ready access to α-methylthio- or α-phenylthio-substituted acetophenones. The acyl chlorides 1 and 2 reacted also with organoaluminum reagents to give α-sulfenylated alkanones. 相似文献
59.
Takashi Kitayama Maki Nakahira Kae Yamasaki Hiromi Inoue Chika Imada Yuji Yonekura Masataka Awata Hikaru Takaya Yasushi Kawai Kohta Ohnishi Akira Murakami 《Tetrahedron》2013
Zerumbone 1, having powerful latent reactivity and containing two conjugated double bonds and a double conjugated carbonyl group is the major component of the essential oil of wild ginger, Zingiber zerumbet Smith. The conjugation system plays an important role in the expression of biological activity. N-Bromosuccinimide (NBS) reaction of 1 gave high reactive intermediate 2 with an exo-methylene group, which was obtained from 1 quantitatively. Treatment of 2 with nucleophiles gave various zerumbone-pendant derivatives, including C–H, C–O, C–N, and C–C bond formation, maintaining the conjugation system through SN2′-type reaction. Almost all zerumbone-pendant derivatives showed a good value of IC50 against the suppressive effect of NO generation. Among them, amine derivative 5, binding with 2 mol of zerumbone, showed the strongest activity (IC50: 0.24 μM). 相似文献
60.
Taisuke Matsuno Yusuke Nakai Yutaka Maniwa Maki Someya Sota Sato Hiroyuki Isobe 《化学:亚洲杂志》2020,15(2):273-278
In a tight host–guest complex assembled solely by nondirectional van der Waals forces, unique motions of the guest, such as solid‐state inertial rotations, emerge. The regulation of dynamic motions is an important element to be explored for novel functions of such complexes, which may be seemingly difficult to achieve because of the nondirectionality of the assembling forces. A regulated, single‐axis rotation was made possible by choosing an appropriate shape of the guest in the tubular host. Specifically, an ellipsoidal guest was made to stand along a cylinder axis of the host, which consequently resulted in single‐axis rotations of the guest in the solid. The rotational frequency was considerably high for solid‐state rotations but was suppressed to 10 GHz, which was 1/20 of the isotropic rotation of a spherical guest. In‐depth kinetic analyses quantitatively revealed that the entropy cost was a determining factor that regulated the dynamics. 相似文献