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101.
Takashi Nishikawa Reiko Abe Yumiko Sudo Asako Yamada Kayoko Tahara 《Analytical sciences》2004,20(10):1395-1398
Peculiarly shaped chromatograms of some compounds that consist of two reversible isomers have been reported. Those of a compound that consists of three reversible isomers are described here. Because disulfide of captopril has two cis-trans convertible bonds, it exists in three forms of cis-cis, cis-trans and trans-trans isomers. The disulfide has produced various HPLC-UV profiles under various conditions, such as three split peaks, three peaks with bridging plateaus and one broad peak. The effect of the column temperature and the eluent flow rate on the profile was investigated and explained by interconversion among three isomers. A profile analysis could provide some kinetic constants of this reaction. 相似文献
102.
Planar Chiral Dialkoxysilane: Introduction of Inherent Chirality and High Reactivity in Conventional Achiral Alkene
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Prof. Dr. Katsuhiko Tomooka Shouji Miyasaka Shougo Motomura Dr. Kazunobu Igawa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(25):7598-7602
A simple eight‐membered dialkoxysilane (E)‐ 1 prepared from 2‐pentene‐1,5‐diol, showed remarkably stable planar chirality along with high reactivity toward epoxidation, Diels–Alder reaction, and cycloaddition reaction with azide. 相似文献
103.
Formation,Expansion, and Interconversion of Metallarings in a Sulfur‐Bridged AuICoIII Coordination System
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Katsuya Oji Dr. Asako Igashira‐Kamiyama Dr. Nobuto Yoshinari Prof. Takumi Konno 《Angewandte Chemie (International ed. in English)》2014,53(7):1992-1996
A novel AuICoIII coordination system that is derived from the newly prepared [Co(D ‐nmp)2]? ( 1 ?; D ‐nmp=N‐methyl‐D ‐penicillaminate) and a gold(I) precursor AuI is reported. Complex 1 ? acts as a sulfur‐donating metallaligand and reacts with the gold(I) precursor to give [Au2Co2(D ‐nmp)4] ( 2 ), which has an eight‐membered AuI2CoIII2 metallaring. Treatment of 2 with [Au2(dppe)2]2+ (dppe=1,2‐bis(diphenylphosphino)ethane) leads to the formation of [Au4Co2(dppe)2(D ‐nmp)4]2+ ( 3 2+), which consists of an 18‐membered AuI4CoIII2 metallaring that accommodates a tetrahedral anion (BF4?, ClO4?, ReO4?). In solution, the metallaring structure of 3 2+ is readily interconvertible with the nine‐membered AuI2CoIII metallaring structure of [Au2Co(dppe)(D ‐nmp)2]+ ( 4 +); this process depends on external factors, such as solvent, concentration, and nature of the counteranion. These results reveal the lability of the Au? S and Au? P bonds, which is essential for metallaring expansion and contraction. 相似文献
104.
Sato S Murata A Orihara T Shirakawa T Suenaga K Kigoshi H Uesugi M 《Chemistry & biology》2011,18(1):131-139
Aurilide is a potent cytotoxic marine natural product that induces apoptosis in cultured human cells at the picomolar to nanomolar range; however, its mechanism of action has been unknown. Results of the present study showed that aurilide selectively binds to prohibitin 1 (PHB1) in the mitochondria, activating the proteolytic processing of optic atrophy 1 (OPA1) and resulting in mitochondria-induced apoptosis. The mechanism of aurilide cytotoxicity suggests that PHB1 is an apoptosis-regulating protein amenable to modulation by small molecules. Aurilide may serve as a small-molecule tool for studies of mitochondria-induced apoptosis. 相似文献
105.
Waki R Yamayoshi A Kobori A Murakami A 《Chemical communications (Cambridge, England)》2011,47(14):4204-4206
In situ visualization of c-fos mRNA was shown both in fixed cells and in living cells using bispyrene-modified 2'-O-methyl RNA probes (OMUpy2) or phosphorothioate modified OMUpy2 (OMUpy2-S), which was RNA-specific with high sensitivity, and a system for time-lapse imaging of c-fos mRNA was successfully developed. 相似文献
106.
Grace D. Metcalfe Asako Hirai Erin C. Young James S. Speck Hongen Shen Michael Wraback 《固体物理学:研究快报》2013,7(11):993-996
We employ near‐bandgap terahertz emission spectroscopy to study lateral heterostructures resulting from basal plane stacking faults in m ‐plane GaN. The predominant stacking faults have I1 character and behave as an array of spontaneously forming layers comprised of a single cubic stacking sequence within the wurtzite matrix that terminate the spontaneous polarization along the in‐plane c‐axis, leading to strong lateral electric fields. Spectral tuning of femtosecond excitation pulses enables observation of the transition from carrier transport in the continuum to formation of instantaneous dipoles and nonlinear susceptibility associated with both the quantum‐well‐like regions of the cubic layers and polarization‐induced triangular‐like potentials. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
107.
108.
Kido A Togashi K Nakai A Kataoka M Fujiwara T Kataoka ML Fujimoto R Koyama T Fujii S 《Magnetic resonance imaging》2006,24(9):1149-1155
BACKGROUND: In women of reproductive age, wavelike movements of the subendometrial myometrium, which is called uterine peristalsis, is considered to be related with fertility and menstrual problems. This is because the direction and frequency of peristalsis is known to be different among menstrual cycle phases. However, nothing is known as regarding diurnal variations. This study was designed to evaluate for the presence of a diurnal variation in uterine peristalsis. MATERIALS AND METHODS: MR studies were performed on 12 volunteers of reproductive age using a 1.5-T magnet, four times per day (at 0800, 1300, 1800 and 2300 h) during three (periovulatory, luteal and menstrual) phases of one menstrual cycle. Sixty images were obtained by half-Fourier acquisition single-shot turbo spin echo every 2 s and displayed on cine mode. Semiautomated software was utilized to discern the presence of peristaltic waves, as well as peristaltic frequency and direction. The presence of sustained contractions was visually determined. RESULTS: There was no statistically significant difference during the daytime for frequency and direction of uterine peristalsis for all menstrual cycle phases. Nonetheless, peristaltic frequency and direction fluctuated during each cycle. Statistically significant peristaltic suppression was observed in association with sustained contractions during the periovulatory phase. CONCLUSIONS: A diurnal variation was not observed for uterine peristalsis. Sporadic changes in peristaltic frequency were observed and appear to be closely related to sustained uterine contractions. 相似文献
109.
110.
In conformity with the conclusion obtained previously, the mixed micelle formation of surfactants was treated thermodynamically as the appearance of a macroscopic bulk phase with the aid of the excess thermodynamic quantities similar to those used for the adsorbed film. The composition of surfactant in the mixed micelle and the thermodynamic quantities of micelle formation were found to be evaluated by applying the thermodynamic equations derived. These equations were extended so as to be applicable to any kind of surfactant mixture. It was shown that the critical micelle concentration vs. composition of surfactant curves form a diagram analogous to the phase diagram of binary mixture. Applying the equation to the published data on typical surfactant systems, this thermodynamic approach was proved to be useful to clarify the miscibility of surfactants in the micellar state. 相似文献