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91.
92.
Summary In order to investigate the kinetics of CO2dissociation on supported nickel catalysts, a novel technique, which can give the surface reaction rate constants with no
information on the number of active sites, was developed. It was revealed that CO2dissociation was more enhanced on TiO2support than on other metal oxide ones. The activity pattern and activation energies were in good agreement with those obtained
by a conventional pulse technique using the number of active sites, suggesting the validity of the present technique for investigating
the kinetics of the surface reaction.</o:p> 相似文献
93.
94.
Sugimoto K Nishida M Otsuka M Makino K Ohkubo K Mori Y Morii T 《Chemistry & biology》2004,11(4):475-485
Real-time observation of messenger molecules in individual intact cells is essential for physiological studies of signaling mechanisms. We have developed a novel inositol 1,4,5-trisphosphate (IP(3)) sensor based on the pleckstrin homology (PH) domain from phospholipase C (PLC) delta. The environmentally sensitive fluorophore 6-bromoacetyl-2-dimethyl-aminonaphtalene was conjugated to the genetically introduced cysteine at the mouth of the IP(3) binding pocket for enhanced IP(3) selectivity and for rapid and direct visualization of intracellular IP(3) > or = 0.5 microM as fluorescence emission decreased. The probe, tagged with arginine-rich sequences for efficient translocation into various cell types, revealed a major contribution of Ca2+ influx to PLC-mediated IP(3) production that boosts Ca2+ release from endoplasmic reticulum. Thus, our IP(3) probe was extremely effective to quantitatively assess real-time physiological IP(3) production via those pathways formed only in the intact cellular configuration. 相似文献
95.
Tatoulian M Bouloussa O Morière F Arefi-Khonsari F Amouroux J Rondelez F 《Langmuir : the ACS journal of surfaces and colloids》2004,20(24):10481-10489
Low-pressure low-frequency NH3 plasmas have been used for the surface modification of bulk polyethylene films and of octadecyltrichlorosilane (OTS) self-assembled monolayers deposited on oxidized silicon wafers. The incorporation of nitrogen-containing groups by the plasma treatment has been followed by contact angle measurements and by X-ray photoelectron spectroscopy. The surface degradation of the OTS monolayers due to plasma etching has been measured separately by optical ellipsometry with subnanometric accuracy. Our data show clear evidence for the existence of an optimum treatment time, yielding a high density of NH2 functional groups without significant variation of the structural features of the organic material. Self-assembled monolayers appear as excellent model systems to characterize the effects of plasma discharges on polyolefins. In particular, they allow testing the influence of molecular orientation, packing density, and crystallinity on the final results. 相似文献
96.
Combinatorial library of isoxazoles was prepared by 1,3-dipolar cycloaddition on solid support. p-Cyano derivatives showed nematic and/or smectic A phases. A bilayer smectic phase for 2h is proposed by the combination of molecular mechanics calculation and X-ray diffraction experiment. 相似文献
97.
Onodera K Nakamura H Oba Y Ohizumi Y Ojika M 《Journal of the American Chemical Society》2005,127(29):10406-10411
Zooxanthellamide Cs (ZAD-Cs), C(128)H(220)N(2)O(53)S(2) (ca. 2.7 kDa), was obtained from a cultured marine dinoflagellate of the genus Symbiodinium as an inseparable isomeric mixture of polyhydroxylated 61- to 66-membered macrolides. The chemical structures of the components were clarified by detailed 2D NMR analysis to be the macrolactonized analogues of zooxanthellamide A (ZAD-A), which had been previously isolated from the same microalgae. Chemical lability of ZAD-Cs suggests that ZAD-A is an artifact derived from ZAD-Cs during the isolation steps. Three of the components possess the largest (63-, 64-, and 66-membered) ring sizes found to date among the natural macrolides. ZAD-Cs exhibited higher vasoconstrictive activity than that of the zooxanthellatoxins, the first vasoconstrictive macrolides from Symbiodinium sp. The structure-activity relationship suggests that the huge macrolactone structure is important for biological activity. The relationship between the structures of the polyol metabolites and the phylogenetic systematics of Symbiodinium sp. is also discussed. 相似文献
98.
Regioselective 1,4-addition of nucleophiles to 1,3-diene monoepoxides catalyzed by palladium complex
1,3-Diene monoepoxides react with nucleophiles in the presence of palladium complex as a catalyst under neutral conditions to give 1,4-adducts selectively. The 1,4-adducts are allylic alcohols and there is a possibility of another nucleophilic attack. Ester of Monarch butterfly pheromone was prepared. 相似文献
99.
E. Miyoshi T. Iura Y. Sakai H. Tochihara S. Tanaka H. Mori 《Journal of Molecular Structure》2003,630(1-3):225-232
We investigated the interactions between the Si(111) surface and the Na, Mg, and Al atoms using cluster model calculations. Calculations were performed at levels of complete-active-space self-consistent-field (CASSCF) and multi-reference singly and doubly excited configuration interaction (MRSDCI) calculations using the model core potential method. Our calculations revealed that the most favorable sites of Na, Mg, and Al adsorption on Si(111) are on top (T1), bridge (B2), and 3-fold filled (T4) sites, respectively. The nature of chemical bonds between these metal atoms and the dangling bonds of the surface Si atoms are found to be essentially covalent. 相似文献
100.
Mori M Saito N Tanaka D Takimoto M Sato Y 《Journal of the American Chemical Society》2003,125(19):5606-5607
Novel alkenylative cyclization of enyne was developed using Cp*RuCl(cod) under ethylene gas at room temperature. 相似文献