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排序方式: 共有925条查询结果,搜索用时 140 毫秒
91.
E. Manova T. Tsoncheva Cl. Estourns D. Paneva K. Tenchev I. Mitov L. Petrov 《Applied Catalysis A: General》2006,300(2):170-180
Nanosized iron and mixed iron–cobalt oxides supported on activated carbon materials and their bulk analogues prepared by thermal synthesis are studied by X-rays diffraction, Mössbauer spectroscopy, magnetic measurements and temperature programmed reduction. Their catalytic behavior in methanol decomposition to H2, CO and methane is tested. Phase transformations in the metal oxides affected by the reaction medium are also investigated. Changes in the reaction mechanism of the methanol decomposition after the metal oxides deposition on the support as compared to the bulk phases are discussed. 相似文献
92.
93.
José R. Bresolin Maria-Claudia T. Largura Camila C. Dalri Geórgia Hoffer Clóvis A. Rodrigues 《Drug development and industrial pharmacy》2014,40(4):503-510
Objective: The aim of the present investigation was to evaluate the use of spray-dried O-carboxymethyl chitosan (OCMCS) as potential hydrophilic matrix excipient for sustained release of drug.Methods: The polymer was synthesized from chitosan, then spray-dried and characterized. Tablets with different OCMCS concentrations (80, 50, 30, 5 and 2% w/w), containing diltiazem (DTZ) as model drug, were prepared for direct compression (DC) and after the wet granulation method (WG).Results: The spray-dried OCMCS powder was spherical, with a smooth surface and an average size of 2.2?µm. The tablets prepared for WG disintegrated in time less than 30?min. The tablets obtained for DC presented high retention of the drug, with zero order or Higuchi release kinetic. There was a direct relationship between the OCMCS concentration and the release ratio, swelling degree and water uptake behavior. DC tablets containing 80% OCMCS presented behavior as an effective swelling-control system. The DC tablets with 5% OCMCS showed a similar release profile at formulations with 30% HPMC.Conclusion: Spray-dried OCMCS showed great potential as hydrophilic matrices for drug-sustained release. 相似文献
94.
Ordering Effects in Benzo[1,2‐b:4,5‐b′]difuran‐thieno[3,4‐c]pyrrole‐4,6‐dione Polymers with >7% Solar Cell Efficiency
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95.
Jonas Croissant Arnaud Chaix Olivier Mongin Miao Wang Sébastien Clément Laurence Raehm Jean‐Olivier Durand Vincent Hugues Mireille Blanchard‐Desce Marie Maynadier Audrey Gallud Magali Gary‐Bobo Marcel Garcia Jie Lu Fuyuhiko Tamanoi Daniel P. Ferris Derrick Tarn Jeffrey I. Zink 《Small (Weinheim an der Bergstrasse, Germany)》2014,10(9):1752-1755
96.
Quartz Films: Water‐Induced Phase Separation Forming Macrostructured Epitaxial Quartz Films on Silicon (Adv. Funct. Mater. 35/2014)
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97.
G Bujacz J Alexandratos ZL Qing C Clément-Mella A Wlodawer 《Canadian Metallurgical Quarterly》1996,398(2-3):175-178
We solved the structure and traced the complete active site of the catalytic domain of the human immunodeficiency virus type 1 integrase (HIV-1 IN) with the F185H mutation. The only previously available crystal structure, the F185K mutant of this domain, lacks one of the catalytically important residues, E152, located in a stretch of 12 disordered residues [Dyda et al. (1994) Science 266, 1981-1986]. It is clear, however, that the active site of HIV-1 IN observed in either structure cannot correspond to that of the functional enzyme, since the cluster of three conserved carboxylic acids does not create a proper metal-binding site. The conformation of the loop was compared with two different conformations found in the catalytic domain of the related avian sarcoma virus integrase [Bujacz et al. (1995) J. Mol. Biol. 253, 333-346]. Flexibility of the active site region of integrases may be required in order for the enzyme to assume a functional conformation in the presence of substrate and/or cofactors. 相似文献
98.
O. Windhausen Fr. Bartschat Max Müller R. Strohecker E. Bodländer Cl. Grimme und J. Großfeld 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1926,52(5):402-422
Ohne ZusammenfassungIn die Zusammenstellung der Referate sind auch die Originalmitteilungen nochmals aufgenommen und durch Kursiv-Typen der Seitenzahlen kenntlich gemacht. 相似文献
99.
Valérie Finidori-Logli Anne-Geneviève Bagnères Dirk Erdmann Wittko Francke Jean-Luc Clément 《Journal of chemical ecology》1996,22(11):2063-2079
The sexual behavior of the ectoparasitoidDiglyphus isaea is described. Recognition of the female by the male occurs at close range. Males initiate courtship behavior in the presence of a living female regardless of age, as well as in the presence of a female killed by freezing. Courtship behavior is not observed in the presence of a dead female washed with organic solvents but could be elicited using a lure covered with a female organic extract. These findings demonstrate that each sex develops a specific chemical signature that can be dissolved in hexane and transferred to a lure. Analysis of organic extracts by gas chromatography revealed chemical dimorphism between the two sexes. Gas chromatography coupled with mass spectrometry showed that the main components in females were esters of medium-chain fatty acids and long-chain 11-alcohols. There were few hydrocarbons. Female esters, which were present in only small proportions in males, were recovered in the nonhydrocarbon fraction obtained after fractionation of the total extract on a silica-filled microcolumn as a mixture containing 11-heneicosyl, 11-docosyl, 11-tricosyl, 11-tetracosyl, and 11-pentacosyl octanoate, and 11-docosyl, 11-tricosyl, 11-tetracosyl, and 11-pentacosyl decanoate. These results demonstrate that there is a specific gender-related chemical signature. 相似文献
100.