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91.
92.
Jing‐Mei Bao Min‐Hong Jiang Shu‐Ling Lin Zhi‐You Su Gui‐Hua Tang Sheng Yin 《Helvetica chimica acta》2015,98(10):1387-1394
Five new cassane diterpenoids, caesalmins I–M ( 1 – 5 ), and 23 known analogs were isolated from the seeds of Caesalpinia minax. Their structures were elucidated by spectroscopic methods and comparison with reported data. The antioxidant properties of 1 – 28 were determined by the method of oxygen radical absorbance capacity of fluorescein (ORAC‐FL), and 14 compounds exhibited good antioxidant activities with ORAC‐FL values of 2.24–4.89 Trolox equivalents. The structure? activity relationship of the active compounds was also discussed. 相似文献
93.
Facile Synthesis of the Pentasaccharide Repeating Unit of the Exopolysaccharide from Cryptococcus neoformans Serotype D 下载免费PDF全文
Sheng‐Jun Huang Jun Liao Hong‐Gang Hu Qing‐Jie Zhao Qiu‐Ye Wu 《Helvetica chimica acta》2015,98(5):618-626
β‐D ‐GlcpA‐(1→2)‐[β‐D ‐Xylp‐(1→2)‐α‐D ‐Manp‐(1→3)]‐α‐D ‐Manp‐(1→3)‐α‐D ‐Manp, the repeating unit of the exopolysaccharide from Cryptococcus neoformans serotype D, was synthesized as its 4‐methoxyphenyl glycoside. The approach presented here also provides a route to the synthesis of more complex repeating units of glucuconoxylomannan (GXM) of C. neoformans serotypes A–C. 相似文献
94.
95.
Ting‐Zheng Xie Kai Guo Zaihong Guo Wen‐Yang Gao Lukasz Wojtas Guo‐Hong Ning Mingjun Huang Xiaocun Lu Jing‐Yi Li Sheng‐Yun Liao Yu‐Sheng Chen Charles N. Moorefield Mary Jane Saunders Stephen Z. D. Cheng Chrys Wesdemiotis George R. Newkome 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(32):9259-9259
96.
97.
Green Approach to the Fabrication of Superhydrophobic Mesh Surface for Oil/Water Separation 下载免费PDF全文
We report a simple and environment friendly method to fabricate superhydrophobic metallic mesh surfaces for oil/water separation. The obtained mesh surface exhibits superhydrophobicity and superoleophilicity after it was dried in an oven at 200 °C for 10 min. A rough silver layer is formed on the mesh surface after immersion, and the spontaneous adsorption of airborne carbon contaminants on the silver surface lower the surface free energy of the mesh. No low‐surface‐energy reagents and/or volatile organic solvents are used. In addition, we demonstrate that by using the mesh box, oils can be separated and collected from the surface of water repeatedly, and that high separation efficiencies of larger than 92 % are retained for various oils. Moreover, the superhydrophobic mesh also possesses excellent corrosion resistance and thermal stability. Hence, these superhydrophobic meshes might be good candidates for the practical separation of oil from the surface of water. 相似文献
98.
Iridium‐ and Osmium‐decorated Reduced Graphenes as Promising Catalysts for Hydrogen Evolution 下载免费PDF全文
Chee Shan Lim Prof. Zdeněk Sofer Rou Jun Toh Alex Yong Sheng Eng Jan Luxa Prof. Martin Pumera 《Chemphyschem》2015,16(9):1898-1905
Renewable energy sources are highly sought after as a result of numerous worldwide problems concerning the environment and the shortage of energy. Currently, the focus in the field is on the development of catalysts that are able to provide water splitting catalysis and energy storage for the hydrogen evolution reaction (HER). While platinum is an excellent material for HER catalysis, it is costly and rare. In this work, we investigated the electrocatalytic abilities of various graphene–metal hybrids to replace platinum for the HER. The graphene materials were doped with 4f metals, namely, iridium, osmium, platinum and rhenium, as well as 3d metals, namely, cobalt, iron and manganese. We discovered that a few hybrids, in particular iridium‐ and osmium‐doped graphenes, have the potential to become competent electrocatalysts owing to their low costs and—more importantly—to their promising electrochemical performances towards the HER. One of the more noteworthy observations of this work is the superiority of these two hybrids over MoS2, a well‐known electrocatalyst for the HER. 相似文献
99.
Solid‐phase extraction based on a molecularly imprinted polymer for the selective determination of four benzophenones in tap and river water 下载免费PDF全文
Hao Sun Yun Li Chaonan Huang Junyu Peng Jiajia Yang Xiaoli Sun Shuliang Zang Jiping Chen Xiangdong Zhang 《Journal of separation science》2015,38(19):3412-3420
This work reports the preparation of molecularly imprinted polymer particles for the selective extraction and determination of four benzophenones from aqueous media. The polymer was prepared by using 4‐vinylpridine as functional monomer, ethylene glycol dimethacrylate as cross‐linker, acetonitrile as porogenic solvent and 2,2’,4,4’‐tetrehydroxybenzophenone as template. Good specific adsorption capacity (Qmax = 27.90 μmol/g) for 2,2’,4,4’‐tetrehydroxybenzophenone was obtained in the sorption experiment and good class selectivity for 2,2’,4,4’‐tetrehydroxybenzophenone, 2,4‐dihydroxybenzophenone, 2,2’‐dihydroxy‐4‐methoxybenzophenone, 2,2’‐dehydroxy‐4,4’‐dimethoxybenzophenone was demonstrated by the chromatographic evaluation experiment. Factors affecting the extraction efficiency of the molecularly imprinted solid‐phase extraction procedure were investigated systematically. An accurate and sensitive analytical method based on the molecularly imprinted solid‐phase extraction coupled with high‐performance liquid chromatography and diode array detection has been successfully developed for the simultaneous determination of four benzophenones from tap water and river water with method detection limits of 0.25–0.72 ng/mL. The recoveries of benzophenones for water samples at two spiking levels (500 and 5000 ng/mL for each benzophenone) were in the range of 86.9–103.3% with relative standard deviations (n = 3) below 9.2%. 相似文献
100.
Histidine‐modified organic‐silica hybrid monolithic column for mixed‐mode per aqueous and ion‐exchange capillary electrochromatography 下载免费PDF全文
Sheng Tang Shujuan Liu Xiaojing Liang Xiaofen Tang Xingcai Wu Yong Guo Xia Liu Shengxiang Jiang 《Journal of separation science》2015,38(12):2046-2052
A novel organic‐silica hybrid monolith was prepared through the binding of histidine onto the surface of monolithic matrix for mixed‐mode per aqueous and ion‐exchange capillary electrochromatography. The imidazolium and amino groups on the surface of the monolithic stationary phase were used to generate an anodic electro‐osmotic flow as well as to provide electrostatic interaction sites for the charged compounds at low pH. Typical per aqueous chromatographic behavior was observed in water‐rich mobile phases. Various polar and hydrophilic analytes were selected to evaluate the characteristics and chromatographic performance of the obtained monolith. Under per aqueous conditions, the mixed‐mode mechanism of hydrophobic and ion‐exchange interactions was observed and the resultant monolithic column proved to be very versatile for the efficient separations of these polar and hydrophilic compounds (including amides, nucleosides and nucleotide bases, benzoic acid derivatives, and amino acids) in highly aqueous mobile phases. The successful applications suggested that the histidine‐modified organic‐silica hybrid monolithic column could offer a wide range of retention behaviors and flexible selectivities toward polar and hydrophilic compounds. 相似文献