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991.
Xiu-Jun Wang Ming-Li Yang Lan-Ping Zhang Tong Yao Cheng Chen Lian-Gang Mao Yin Wang Jie Wu 《中国化学快报》2014,25(4):589-592
A new series of bis-benzimidazole derivatives were designed and synthesized.In vitro cytotoxicity evaluation showed that these compounds exhibited high activity against the selected tumor cells.Among them,compound 9 owned the best potential,its IC_(50) values being 5.95 μmol/L(mononuclear tumor cell line(U937)) and 5.58 μmol/L(cervical cancer cell(HeLa)).Fluorescence and UV-vis studies showed that compound 9 could bind into the minor groove of DNA. 相似文献
992.
Long Zhang Yang-Ping Wen Yuan-Yuan Yao Zi-Fei Wang Xue-Min Duan Jing-Kun Xu 《中国化学快报》2014,25(4):517-522
A simple,sensitive,and reliable method for the voltammetric determination of bisphenol A(BPA) by using carboxylic group functionalized single-walled carbon nanotubes(f-SWCNT)/carboxylic-functionalized poly(3,4-ethylenedioxythiophene)(PC4) complex modified glassy carbon electrode(GCE) has been successfully developed.The electrochemical behavior of BPA at the surface of the modified electrode is investigated by electrochemical techniques.The cyclic voltammetry results show that the as-prepared electrode exhibits strong catalytic activity toward the oxidation of BPA with a well-defined anodic peak at 0.623 V in PBS(0.1 mol/L,pH 7.0).The surface morphology of the 3D network of composite film is beneficial for the adsorption of analytes.Under the optimized conditions,the oxidation peak current is proportional to BPA concentration in the range between 0.099 and 5.794 μmol/L(R~2 = 0.9989),with a limit of detection of 0.032 μmol/L(S/N = 3).The enhanced performance of the sensor can be attributed to the excellent electrocatalytic property of/-SWCNT and the extraordinary conductivity of PC4.Furthermore,the proposed modified electrode displays high stability and good reproducibility.The good result on the voltammetric determination of BPA also indicates that the asfabricated modified electrode will be a good candidate for the electrochemical determination and analysis of BPA. 相似文献
993.
A chiral catalyst, Cp*RhTsDPEN (Cp* = pentamethyl cyclopentadiene, TsDPEN = substitutive phenylsulfonyl-l,2-diphenylethylenediamine), was synthesized and immobilized at the surface of glass. The immobilized catalyst exhibited good catalytic efficiency for asymmetric transfer hydrogenation of aromatic ketones in water with HCOONa as hydrogen source. 相似文献
994.
995.
996.
Huimin Wang Rui Ma Pengjun Shi Xianli Xue Huiying Luo Huoqing Huang Yingguo Bai Peilong Yang Bin Yao 《Applied biochemistry and biotechnology》2014,174(1):328-338
An α-galactosidase gene (gal36A4) of glycosyl hydrolase family 36 was identified in the genome of Alicyclobacillus sp. A4. It contains an ORF of 2,187 bp and encodes a polypeptide of 728 amino acids with a calculated molecular mass of 82.6 kDa. Deduced Gal36A4 shows the typical GH36 organization of three domains—the N-terminal β-sheets, the catalytic (β/α)8-barrels, and the C-terminal antiparallel β-sheet. The gene product was produced in Escherichia coli and showed both hydrolysis and transglycosylation activities. The optimal pH for hydrolysis activity was 6.0, and a stable pH range of 5.0–11.0 was found. The enzyme had a temperature optimum of 60 °C. It is specific for α-1,6-glycosidic linkages and had a K m value of 1.45 mM toward pNPGal. When using melibiose as both donor and acceptor of galactose, Gal36A4 showed the transfer ratio of 23.25 % at 96 h. With respect to acceptor specificity, all tested monosaccharides, disaccharides, and oligosaccharides except for D-xylose and L-arabinose were good acceptors for transglycosylation. Thus, Gal36A4 may find diverse applications in industrial fields, especially in the food industry. 相似文献
997.
Two new Brønsted acids [2,2′-ethylidene-bis (4,6-di-tert-butylphenol)] phosphoric acid (EDBPPOOH) and (3,3′,5,5′-tetra-tert-butylbiphenyl-2,2′-diol) phosphoric acid (TBPO-POOH) were synthesised and fully characterised by 1H NMR and 13C NMR spectra and mass spectra. The ringopening polymerisation (ROP) of ?-caprolactone (?-CL) catalysed by the two Brønsted acids proceeded at 110°C without a solvent or at ambient temperature in toluene. Experimental results indicated that the two Brønsted acids were efficient catalysts for the ROP of ?-CL with moderate number-average molar mass (Mn) and narrow polydispersity indices (PDI). The catalytic activity of TBPO-POOH is higher than EDBP-POOH in the ROP of ?-CL. After benzyl alcohol was added, it was able to accelerate the polymerisation process. The polymerisation can also occur with the addition of water with a monomer/catalyst/initiator mole ratio of 100: 1: 1. The living polymerisation was ascertained by the linear relationships of the Mn vs. monomer conversion, then it was further confirmed by a second-feed experiment of a double monomer producing double Mn. A kinetic study of the relationships between monomer concentration and time revealed a first-order dependence on monomer concentration in the polymerisation. End-group analysis of 1H NMR spectra and electrospray-ionisation mass spectra suggests that the two Brønsted acids are capable of catalysing and initiating the ROP of ?-CL. 相似文献
998.
Zhihua Zhao Xiaoqing Shen Hongchang Yao Jianshe Wang Jinzhou Chen Zhongjun Li 《Journal of Sol-Gel Science and Technology》2014,70(1):72-80
Alumina nanofibers were fabricated by calcination of the polyvinylpyrrolidone (PVP)/pseudo-boehmite nanocomposite precursor fibers formed by electrospinning PVP/ethanol solution of dispersed pseudo-boehmite nanoparticles with and without additive of silica. The evolution of the phase, mechanical property and morphological features of the calcined fibers were studied and the effect of adding SiO2 on the phase transformation of alumina was discussed. Adding SiO2 can retard the phase transformation of γ-Al2O3 to α-Al2O3 and therefore inhibit the growth of alumina grains during calcination. Upon calcining the precursor fibers with 4 wt% SiO2 additive at 1,300 °C, continuous alumina nanofibers with diameter ranging from 300 to 800 nm were obtained. These continuous nanofibers exhibited good flexibility and could be very promising for applications in filtration and catalyst support. 相似文献
999.
采用在流动相中添加四氢呋喃的方法来改善丙烯醛-2,4-二硝基苯肼(DNPH)和丙酮-DNPH的分离,然后优化流动相比例和梯度,确定了UPLC分析醛酮-DNPH的色谱条件。有机溶剂消耗量和分析时间分别是传统方法的1/20~1/10和12%~30%;工作曲线线性相关系数、方法检出限和测定下限均满足HJ683-2014的规定;UPLC法测定醛酮的2,4-二硝基苯肼衍生物的平均回收率为91.5%~101%。基于常规的超高效反向C18色谱柱,在40℃条件下建立了高效分离醛酮混标的UPLC方法,方法已用于测定餐饮油烟中醛酮类化合物。 相似文献
1000.
建立了同时检测蜂胶中16种磺胺及2种林可胺类药物残留的方法,以1.0 mol/L HCl溶液为提取液,经阳离子固相萃取小柱净化富集后,高效液相色谱-串联质谱仪分析。采用Agilent Polaris C18色谱柱(100 mm×2.0 mm,5μm),以甲醇和0.1%甲酸为流动相梯度洗脱,质谱模式为电喷雾正离子监测。该方法前处理简单,分别以13C6-磺胺二甲基嘧啶、13C6-磺胺甲噁唑为磺胺类药物内标、以D3-林可霉素为林可胺类药物内标进行定量,磺胺和林可胺类药物的线性范围均为1.0~50μg/L,相关系数均在0.99以上,方法定量限为10.0μg/kg,在10,20和40μg/kg 3个水平做添加回收,回收率范围为69.5%~114.6%,相对标准偏差小于10%。 相似文献