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991.
992.
Structural effects of electrochemical oxidation of formic acid on single crystal electrodes of palladium 总被引:1,自引:0,他引:1
Hoshi N Kida K Nakamura M Nakada M Osada K 《The journal of physical chemistry. B》2006,110(25):12480-12484
Structural effects on the rates of formic acid oxidation have been studied on Pd(111), Pd(100), Pd(110), and Pd(S)-[n(100) x (111)] (n = 2-9) electrodes in 0.1 M HClO4 containing 0.1 M formic acid with use of voltammetry. On the low index planes of Pd, the maximum current density of formic acid oxidation (jP) increases in the positive scan as follows: Pd(110) < Pd(111) < Pd(100). This order differs from that on the low index planes of Pt: Pt(111) < Pt(100) < Pt(110). Pd(S)-[n(100) x (111)] electrodes with terrace atomic rows n > or = 3 have almost the same jP as Pd(100), except Pd(911) n = 5. The value of jP on Pd(911) n = 5 is 20% higher than those of the other surfaces. Pd(311) n = 2, of which the first layer is composed of only step atoms, has the lowest jP in the Pd(S)-[n(100) x (111)] series. The adsorption geometry of the reaction intermediate (formate ion) is optimized by using density functional theory. 相似文献
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S el-Mekkawy M R Meselhy N Nakamura M Hattori T Kawahata T Otake 《Chemical & pharmaceutical bulletin》1999,47(9):1346-1347
Through bioactivity-guided fractionation, eight phorbol diesters, including five new ones (1-5), were isolated from the seeds of Croton tiglium collected in Egypt. 12-O-Acetylphorbol-13-decanoate (6) and 12-O-decanoylphorbol-13-(2-methylbutyrate) (4) potently inhibited the HIV-1-induced cytopathic effect on MT-4 cells (IC100 values of 7.6 ng/ml and 7.81 micrograms/ml, and CC0 values of 62.5 micrograms/ml and 31.3 micrograms/ml, respectively) without activating protein kinase C. 相似文献
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Hideo Ogiso Kazuhiro Nakamura Yutaka Yatomi Takao Shimizu Ryo Taguchi 《Rapid communications in mass spectrometry : RCM》2010,24(4):436-442
Phosphatidylinositol phosphates (PtdInsPs) are present within the nucleus, as well as in the membrane. In this mass spectrometry study, different acyl‐containing species of endonuclear PtdInsPs were analyzed in order to clearly understand the role of individual molecular species. A (34:1) acyl‐containing phosphatidylinositol bisphosphate [PtdInsP2(34:1)] and PtdInsP2(36:1) were preferentially detected in envelope‐less nuclei prepared from various cultured human cells, while PtdInsP2(38:4) was not a major component within these nuclei. A significant amount of PtdInsP2(34:0) was detected in the HeLa cell nucleus, but not in the A431 and THP‐1 cell nuclei. During the cell cycle in HeLa cells, PtdInsP2(34:0) levels increased in the early G1 phase, and then gradually decreased through S phase, while PtdInsP2(34:1) levels tended to decrease only in late G1 phase and PtdInsP2(38:4) did not change significantly. Thus, individual PtdInsP2 species apparently play different roles in nuclear events based on individual regulation of endonuclear levels. The non‐arachidonate‐containing species were also detected in normal human blood and fluids, suggesting that these minor species may have unique functions in the human body. The techniques used in this study will be applied to clinical studies on a PtdInsPs metabolism. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Toshio Morikawa Xuezheng Li Eriko Nishida Seikou Nakamura Kiyofumi Ninomiya Hisashi Matsuda Yoshimi Oda Osamu Muraoka Masayuki Yoshikawa 《Helvetica chimica acta》2010,93(3):573-586
The MeOH extract from the flowers of Bellis perennis was found to show pancreatic‐lipase inhibitory activity (IC50 455 μg/ml). From the extract, seven new triterpene saponins named perennisaponins G ( 1 ; IC50 163 μM ), H ( 2 ; 137 μM ), I ( 3 ; 147 μM ), J ( 4 ; 148 μM ), K ( 5 ; 223 μM ), L ( 6 ; 81.4 μM ), and M ( 7 ; 195 μM ) were isolated as pancreatic lipase inhibitors. The stereostructures of 1 – 7 were elucidated on the basis of chemical and spectroscopic evidence. 相似文献
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Toshio Nakamura 《Analytical sciences》2007,23(3):253-259
This review first describes the invention of functional interfaces to promote biochemical redox reactions between substrates in dipolar aprotic solvents and enzymes or related compounds immobilized at the interface. The interfaces contain hydrophilic polymer membranes, a gold nanoparticle self-assembled electrode constructed by using rigid rod dithiols, and binary self-assembled monolayers composed of amino and carboxyl terminal groups. Other topics covered are: the electrochemical characterization of the hydrophilic polymer membrane; the development of biosensors to obtain reaction parameters of enzymatic and of electrochemical kinetics; and applications to the study of materials involved in metabolism. 相似文献