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991.
Jian‐Ding Qiu San‐Hua Luo Jian‐Hua Huang Ru‐Ping Liang 《Journal of computational chemistry》2009,30(8):1344-1350
The prediction of secondary structure is a fundamental and important component in the analytical study of protein structure and functions. How to improve the predictive accuracy of protein structural classification by effectively incorporating the sequence‐order effects is an important and challenging problem. In this study, a new method, in which the support vector machine combines with discrete wavelet transform, is developed to predict the protein structural classes. Its performance is assessed by cross‐validation tests. The predicted results show that the proposed approach can remarkably improve the success rates, and might become a useful tool for predicting the other attributes of proteins as well. © 2008 Wiley Periodicals, Inc. J Comput Chem 2009 相似文献
992.
Ru Qiao Dr. Xiao Li Zhang Dr. Ri Qiu Ju Chang Kim Prof. Young Soo Kang Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(8):1886-1892
Co(OH) 2 that blooms : Flowerlike hollow spherical architectures of cobalt hydroxide obtained through a facile solvothermal process are reported for the first time (see picture). Their growth process involves aggregation of cobalt hydroxide nanoparticles into solid spheres and a hollowing effect through subsequent dissolution‐diffusion‐redeposition of the smaller crystallites under the surface layer.
993.
Qing Sheng Zhao Xiao Jie Cheng Qiu Xia Ji Chuan Zhen Kang Xi Guang Chen 《Journal of Sol-Gel Science and Technology》2009,50(1):111-118
The influence of organic and inorganic acids on chitosan/glycerophosphate (CS/GP) hydrogel has been investigated by dissolving
chitosan in different acids. The results of gelation showed that all of the chitosan dissolved in monovalent acid solutions
(i.e., formic, acetic, propionic, butyric, isobutyric, lactic, nitric, hydrochloric, and chloroacetic acid), when neutralized
by GP solution, could transform into hydrogel after 2–5 min at 37 °C, while those dissolved in multivalent acids failed in
gel formation. The inner structures of CS/GP hydrogels prepared with monovalent acids depended on the ionic strength and chain
length of acids. Morphological examination by scanning electron microphotography demonstrated that large pores occurred during
the gel-forming process, and the aperture size was also related to different acids. The cytotoxicity studies indicated that
CS/GP systems prepared by dissolving chitosan in tested acids except chloroacetic acid were nontoxic to mouse embryonic fibroblasts
and Hela cells. 相似文献
994.
Shuifa Qiu Yunyang Wei Prof. Dr. Guosheng Liu Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(12):2751-2754
Taking the air! A PdII‐catalyzed intramolecular hydroamination of allenes coupled to alcohol oxidation has been developed. This reaction is performed by using a nitrogen‐based ligand under aerobic conditions, under which the molecular oxygen is used as the terminal oxidant for the reoxidation of Pd0 species to complete the catalytic cycle.
995.
Renhua Qiu Guoping Zhang Yuyang Zhu Xinhua Xu Lingling Shao Yinhui Li Delie An Shuangfeng Yin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(26):6488-6494
Stable complexes : An extremely air‐stable μ2‐hydroxy‐bridged binuclear hafonocene perfluorooctanesulfoante complex shows high catalytic efficiency in Lewis acid‐catalyzed reactions, such as esterification, Friedel–Crafts acylation, the Mukaiyama aldol reation, and the allylation of aldehyde (see scheme).
996.
Kuo-xi Xu Zhen Qiu Jin-Jin Zhao Jin Zhao Chao-jie Wang 《Tetrahedron: Asymmetry》2009,20(14):1690-1696
The derivatives of BINOL, (S)-1 and (R)-1, and their analogues have been prepared and the structures of these compounds have been characterized by IR, MS, 1H, and 13C NMR spectroscopy and elemental analysis. The enantioselective recognition of these receptors has been studied by fluorescence titration and 1H NMR spectroscopy. The receptors exhibited different chiral recognition abilities toward some enantiomers of chiral materials and formed 1:1 complexes between host and guest. Receptor (S)-1 or (R)-1 exhibits excellent enantioselective fluorescent recognition abilities toward amino acid derivatives. 相似文献
997.
Hydrosilylation has been carried out between Si-H terminated polydimethylsiloxanes with narrow molecular weight distribution and protected 3-allyloxy-1,2-propanediol, and after subsequently alcoholyzed, α-{3-[(2,3-dihydroxy)propoxy]propyl}-ω-butyl-polydimethylsiloxanes with varying number of ((Si(CH3)2-O) unit were obtained. At each step, the produced compounds were carefully characterized. The results showed that each step was successfully carried out and target products were achieved. 相似文献
998.
Ying Peng Huo Xu Qiu Wei Yan Shao Lin Kun An Xian Zhang Bu Lian Quan Gu 《中国化学快报》2009,20(11):1291-1295
Series of new 2-aryl-6-styryl-2,3-dihydropyridin-4(1H)-one derivatives were synthesized in acceptable to good yields by treatment of the curcuminoids with aqueous ammonia,the mechanism was proposed.By modification of the primary products,total 13 new compounds were obtained.The structures of all products were elucidated by spectroscopy analysis including HR-MS,~1H NMR and ~(13)C NMR. 相似文献
999.
Xiao Qiu 《Journal of organometallic chemistry》2009,694(24):3958-6658
Novel ferrocenyl nitroxides 3−6 were prepared as models for studying the linkage structure-activity relationship. Single-crystal X-ray structures of compounds 4 and 5 were determined and comparatively studied. The in vitro antioxidative activities (e.g. scavenging superoxide anion and hydroxide radical) of compounds 3−6 and 4-ferrocenamido-2,2,6,6-tetramethyl-piperidin-oxy (2) were evaluated. Compounds 3 and 5 exhibit high scavenging activities in low concentration. Results from electrochemistry and UV/Vis spectroscopy show that the redox property and antioxidative activity are closely related to the structure of the linkage bridging ferrocene and cyclic nitroxide moieties. The results further indicate that the ferrocene moiety plays a principal role in antioxidation. The modification of linkage was found to be able to decrease the ferrocene/ferrocenium potential and improve the antioxidative activity effectively. 相似文献
1000.