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111.
A novel molecular probe for identifying properties of supported transitionmetals and metal oxides catalysts was established.The catalytic mechanism oftransition metals was proposed. 相似文献
112.
GABAA五种亚型受体与BZ配基的3D-QSAR研究 总被引:1,自引:0,他引:1
GABAA受体是中枢神经系统内重要的抑制性受体,有广泛的神经生理活性.由于镇静/抗惊厥药物在临床上的广泛应用,使得其中苯并二氮杂作用位点尤为重要.我们用比较分子场法(CoMFA)对一系列咪唑苯并二氮杂类化合物(BZ)与五种重组受体亚型的亲和力进行了结构活性关系研究,得到的一组模型都有较高的交叉验证系数.并在此基础上,建立了非交叉验证的一组PLS模型.用该组模型对随机选择的6个化合物组成的测试集进行了预测,都得到了相当满意的结果,表明所建立的一组模型具有良好的预测能力.本研究对于设计高亲和力的BZ受体的配基和研究GABAA受体的模型有指导意义. 相似文献
113.
Recently, we have developed a fast approach to calculate NMR chemical shifts using the divide and conquer method at the semiempirical level. To demonstrate the utility of this approach for characterizing protein-ligand interactions, we used the deviation of calculated chemical shift perturbations from experiment to determine the orientation of a ligand (GPI-1046) in the binding pocket of the FK506 binding protein (FKBP12). Moreover, we were able to select the native state of the ligand from a collection of decoy poses. A key hydrogen bond between O1 and HN in Ile56 was also identified. Our results suggest that ligand-induced chemical shift perturbations can be used to refine protein/ligand structures. 相似文献
114.
DUAN Chun-Ying XIA Xu-Bing ZHU Long-Gen YOU Xiao-Zeng YANG Yao WANG Hua-QinCoordination Chemistry Institute Nanjing University The State Key Laboratory of Coordination Chemistry Nanjing Jiangsu China 《中国化学》1994,(4)
The cobalt, nickel, copper, zinc and cadmium complexes of S-methyl-N-(ferrocenyl-l-methyl-methylidene)-dithiocarbazate (H-LSM) and S-benzyl-N-(ferrocenyl-l-methyl-methylidene)-dithiocarbazate (H-LSB) were synthesized and the crystal structure of Cd[Fe-C(CH3) = NNCSS. (CH3)]2 was solved by X-ray diffraction. The crystal is in the orthorhombic system with space group Pbca, cell parameters a=19.741(3), b=19.924(5), c=15.452(4) A, and the final factors of R=0.032. The study on quenching the luminescence of Ru(bpy)3 by those complexes showed that bimolecular quenching constants obtained from the Stern-Vohner constant and the excited-state lifetime were related to the redox potential of the quencher. Linear relationship is shown in the plot of logkq vs. E1/2(Q+/Q). The main factor which influences the quenching rate constant and the redox potential is the coordinating ability of the metal in the complex. 相似文献
115.
The localization of Terbium (Tb3+) cations binding to deionized bacteriorhodopsin (bR) has been studied by using spectroscopic methods. It was found that adding
Tb3+ cations to deionized bR affects the fluorescence lifetimes of tryptophan (Trp) in bR, the wavelength of fluorescence peak
shifts “blue” and the peak value of fluorescence decreases. It was also found that adding one Tb3+ cation to deionized bR can restore the purple state from its blue state obviously. The measurements of absorbance, fluorescence
and lifetime of fluorescence also show that when more than three Tb3+ cations are added, no further changes can be found. It is suggested that one Tb3+ specific binding site for the color-controlling is located on the exterior of the bR trimer structure to negatively charged
lipids near Trp-10 and Trp-12. Three Tb3+ cations binding per bR is needed for the regenerated bR. 相似文献
116.
Rui Qi SONG * Jian Qing ZENG Bing ZHONG Guangzhou Institute of Chemistry Chinese Academy of Sciences Guangzhou State Key Laboratory of Coal Chemistry Institute of Coal Chemistry Chinese Academy of Sciences Taiyuan School of 《中国化学快报》2002,13(10)
We have studied the palladium-catalyzed alkoxycarbonylation of allyl bromide in supercritical (sc) CO2 and found the reaction rate in sc CO2 was lower than those in some organic solvents1. The possible reason was the lower solubility of sc CO2 for the palladium catalyst. As an effective approach to improve the solubility of varieties of solutes, cosolvent such as ethanol has been widely used in the sc CO2 extraction2,3. Based on the above consideration, we chose several organic reagents… 相似文献
117.
Protoplasts were isolated from embryogenic calli derived from immature embryos ofwheat (Triticum aestivum L. cv. Jinan 177). The protoplasts were cultured in NMB mediumsupplemented with 1mg/L 2,4- D and 500mg/l casein hydrolysate (CH). The regenerated cellsfrom protoplasts divided to form somatic embryos directly. The somatic embryos grown to1.5- 2 mm in size directly developed into complete plants on solid MB medium without hor-mones. 相似文献
118.
119.
Bernd GüNTHER 《中国科学B辑(英文版)》2007,50(6)
The interaction between stabilizers and nanoparticles is one of the important factors to prepare stable magnetic fluids. The magnetic nano-size Fe3O4 core with single domain and the average grain size around 8-12 nm were prepared by chemical precipitation method. The O/Fe molar ratio of the particle surface was measured by X-ray photoelectron spectroscopy (XPS). The heat effects of stabilizers ad- sorption on nanoparticles were measured by solution calorimetry. The excess amount of oxygen was possibly the result of the hydroxygen formed on the surface of the nanoparticles. The heat effects showed that compounds containing carboxyl groups can be adsorbed chemically on magnetite by forming chemical bonds. The other stabilizers involving NH-groups, such as polyethylene-imine, can be adsorbed physically. The exothermic value is about half of the former case. 相似文献
120.
CuO/γ-Al2O3 catalysts were prepared by plasma treatment and conventional impregnation methods. The catalytic combustion of two kinds of volatile organic compounds (VOCs), toluene and benzene, were carried out over these CuO/γ-Al2O3 catalysts. The surface properties of these catalysts were characterized by X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The experimental results showed that in catalytic combustion the activity of the CuO/γ-Al2O3 catalyst prepared via plasma was much higher than that of the CuO/γ-Al2O3 catalyst prepared by conventional impregnation method. XRD results showed that an enhanced dispersion had been achieved with the plasma treatment. SEM results indicated that the size became much smaller and the surface became more uniform with the plasma treatment. 相似文献