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991.
在全球甲型H1N1流感大流行背景下,本文在充分考虑各国甲流感死亡率可能存在个体混合效应、独立效应、相关效应及空间相关效应基础上,运用Bayes计量分析框架下的模型选择标准确定描述各国甲流感死亡率的最优模型,并基于该模型对不同国家甲流感死亡率进行估算。结果显示:个体独立、空间相关效应模型能很好拟合各国甲流感疫情统计数据,利用该模型估算的全球甲流感平均死亡率为0.577%。 相似文献
992.
Yu‐Feng Liang Ning Jiao 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(2):558-562
A transition‐metal‐free Cs2CO3‐catalyzed α‐hydroxylation of carbonyl compounds with O2 as the oxygen source is described. This reaction provides an efficient approach to tertiary α‐hydroxycarbonyl compounds, which are highly valued chemicals and widely used in the chemical and pharmaceutical industry. The simple conditions and the use of molecular oxygen as both the oxidant and the oxygen source make this protocol very environmentally friendly and practical. This transformation is highly efficient and highly selective for tertiary C(sp3) H bond cleavage. 相似文献
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996.
Cobalt‐based metal coordination polymers with 4,4′‐bipyridinyl groups: highly efficient catalysis for one‐pot synthesis of 3,4‐dihydropyrimidin‐2(1H)‐ones under solvent‐free conditions
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Jin‐Hua Wang Gui‐Mei Tang Shi‐Chen Yan Yong‐Tao Wang Shi‐Jie Zhan E Zhang Yu Sun Yuan Jiang Yue‐Zhi Cui 《应用有机金属化学》2016,30(12):1009-1021
Three new metal coordination complexes, namely [Co(BPY)2(H2O)2](BPY)(BS)2(H2O)4 ( 1 ), [Co(BPY)2(H2O)4](ABS)2(H2O)2 ( 2 ) and [Co(BPY)(H2O)4](MBS)2 ( 3 ) (BPY = 4,4′‐bipyridine, BS = phenylsulfonic acid, ABS = p‐aminobenzenesulfonic acid, MBS = p‐methylbenzenesulfonic acid), were obtained under hydrothermal conditions. Complexes 1 , 2 , 3 were structurally characterized using single‐crystal X‐ray diffraction and infrared spectroscopy. All of them display low‐dimensional motifs: complex 1 displays a two‐dimensional structure; and complexes 2 and 3 exhibit a one‐dimensional tape structure. Through strong intermolecular hydrogen bonding interactions and weak packing interactions, all of them further stack to generate a three‐dimensional supramolecular architecture. Catalysts 1 , 2 , 3 were involved in the green synthesis of a variety of 3,4‐dihydropyrimidin‐2(1H)‐ones under solvent‐free conditions through Biginelli reactions. The corresponding catalytic product was obtained in quantitative yields (99%) under eco‐friendly synthesis conditions for the variety of reactions. Catalysts 1 , 2 , 3 exhibit excellent efficiency for the desired product, and their catalytic performance shows the following order: 2 > 1 ≈ 3 , which can be ascribed to the hydrophobic interactions of different phenylsulfonate groups. The catalytic performance for the Biginelli reaction is not only dependent on the selected solvents, but also inversely proportional to the polarities of the solvents. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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Four symmetrical α,α′,δ,δ′-tetramethyl-cucurbit[6]uril-based compounds have been prepared and characterised by X-ray crystallography. Their crystal structures displayed the acetate anion-selective encapsulating capability of symmetrical α,α′,δ,δ′-tetramethyl-cucurbit[6]uril. The host–guest interaction between the symmetrical α,α′,δ,δ′-tetramethyl-cucurbit[6]uril and the acetate anion in aqueous solution has also been observed by variable temperature 1H NMR spectroscopy. 相似文献
999.
Andrii Lozynskyi Borys Zimenkovsky Iryna Ivasechko Julia Senkiv Andrzej Gzella Olexandr Karpenko 《Phosphorus, sulfur, and silicon and the related elements》2013,188(12):1149-1157
AbstractThe synthesis and anticancer activity evaluation of new thiazolo[4,5-b]pyridine-5-carboxylic acid amides is described. The structures of the synthesized compounds were confirmed by spectroscopic data and a single crystal X-ray diffraction analysis for 2.4. The synthesized compounds were screened for their in vitro anticancer activity according to US NCI protocols. The most active 7-(4-fluorophenyl)-2-oxo-2,3-dihydrothiazolo[4,5-b]pyridine-5-carboxylic acid (4-chlorophenyl)amide 2.2 and 7-(4-chlorophenyl)-2-oxo-2,3-dihydrothiazolo[4,5-b]pyridine-5-carboxylic acid (4-chlorophenyl)amide 2.5 were screened for their cytotoxicity effects on C6 Rat glioma cells and U373 Human glioblastoma astrocytoma cells which revealed promising results comparable to temozolamide as reference control according MTT assay data. 相似文献
1000.
Purnima Dixit J. P. Tandon 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4):389-395
Abstract Some organolead(IV) complexes derived from biologically active sulfur and nitrogen donor ligands have been synthesized and characterized by elemental analyses, molecular weight determinations and conductivity measurements. The trigonal bipyramidal and octahedral geometries for these complexes have been proposed on the basis of electronic, infrared and NMR (1H and 13C) spectral evidences. The antifungal activity of some of the ligands and their complexes have also been evaluated against Fursarium oxysporum SCW. ex Frics f. sp. Ciceri (Pedwick) subram. 相似文献