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541.
542.
Zhao M Bai L Toki A Hasegawa R Sakai J Hasegawa T Ogura H Kataoka T Bai Y Ando M Hirose K Ando M 《Chemical & pharmaceutical bulletin》2011,59(3):371-377
A new cardenolide diglycoside (1) was isolated from Nerium oleander together with ten known cardenolide diglycosides 2-11. The structure of compound 1 was established on the basis of their spectroscopic data. The in vitro anti-inflammatory activity of compounds 1-11 was examined on the basis of inhibitory activity against the induction of the intercellular adhesion molecule-1 (ICAM-1). Compounds 2-5 were active at an IC(50) value of less than 0.8 μM. The cytotoxicity of compounds 1-11 was evaluated against three human cell lines normal human fibroblast cells (WI-38), malignant tumor cells induced from WI-38 (VA-13), and human liver tumor cells (HepG2). Compound 3 was active toward VA-13 cells, and compounds 2-5 were active toward HepG2 cells at IC(50) values of less than 1.3 μM. The multidrug resistance (MDR)-reversal activity of compounds 1-11 was evaluated on the basis of the amount of calcein in MDR human ovarian cancer 2780AD cells in the presence of each compound. Compounds 1 and 8 showed moderate effects on calcein accumulation. 相似文献
543.
以TiO2纳米管为模板,采用多组分自组装结合水热法制备Bi2WO6/TiO2纳米管异质结构复合材料。通过多种技术如X射线衍射(XRD),X射线光电子能谱(XPS),N2吸附脱附,扫描电镜(SEM),高分辨透射电镜(HRTEM)和紫外可见漫反射吸收光谱(UV-Vis DRS)考察所制备样品的组成、结构、形貌、光吸收和电子性质。Bi2WO6纳米片或纳米粒子分布在TiO2纳米管上,形成异质结构。随后,通过在紫外、可见和微波辅助光催化模式下降解染料罗丹明B(RhB)来评价复合催化剂的光催化活性。与TiO2纳米管和Bi2WO6相比,Bi2WO6/TiO2-35纳米管在多模式下表现出更优异的光催化活性。与紫外和可见降解模式相比,Bi2WO6/TiO2-35纳米管在微波辅助光催化模式下对RhB的降解效率最高。这种增强的光催化活性源于适量Bi2WO6的引入、纳米管独特的形貌特征和降解模式所引起的增强的量子效率。降解过程中的活性物种被证明是h+,·OH和·O2-自由基。而且,在微波辅助光催化模式下,可产生更多的·OH和·O2-自由基。 相似文献
544.
采用微波辅助结合沉淀法制备了以ZnO为主体的纳米复合材料Ag/ZnO-ZrO2。通过X射线粉末衍射(XRD)、紫外-可见漫反射吸收光谱(UV-Vis/DRS)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)和N2吸附-脱附等表征手段研究了微波辐射对Ag/ZnO-ZrO2晶型结构、形貌及表面物理化学性质的影响。结果表明, 在200 W微波辐射作用下, 该样品晶型结构未发生明显变化, 但Ag的衍射峰明显增强, 同时, 其晶粒尺寸、光吸收性质和表面物理化学性质等方面则发生改变, 尤其是样品Ag/ZnO-ZrO2的形貌呈现了圆形片状结构。分别在紫外和微波辅助条件下对纳米复合材料的光催化性能进行了一系列考察, 同时为了进一步评价所合成样品在太阳光作用下的实用价值, 又考察了Ag/ZnO-ZrO2在模拟日光条件下的光催化性能。结果显示, 紫外光作用下, 纳米复合材料Ag/ZnO-ZrO2的光催化活性高于市售P25以及未经微波处理的样品, 且在微波辅助光催化条件下, 其活性有较大程度提高。200 W微波功率下所合成样品Ag/ZnO-ZrO2在模拟日光作用下显现出较高活性。另外, 根据紫外光条件下对光催化活性物种的捕获实验提出了Ag/ZnO-ZrO2可能的光催化机理。 相似文献
545.
磁性胰蛋白酶分子印迹聚合物的制备及性能评价 总被引:1,自引:0,他引:1
以壳聚糖修饰的四氧化三铁为载体,利用壳聚糖表面的氨基与戊二醛结合,丙烯酰胺为功能单体和交联剂,胰蛋白酶为模板蛋白,制备了磁性胰蛋白酶分子印迹聚合物。通过静态平衡结合法研究了磁性分子印迹聚合物的吸附能力、选择性。结果表明,与磁性分子非印迹聚合物相比,磁性分子印迹聚合物对模板蛋白具有高选择性和高特异性吸附,最大吸附量为162.2mg·g-1;Scatchard分析表明,存在两类不同的吸附结合位点,其离解常数分别为96.5μg·mL-1(高结合位点)和2.41mg.mL-1(低结合位点)。 相似文献
546.
以莱克多巴胺为模板分子、甲基丙烯酸为功能单体、乙二醇二甲基丙烯酸酯为交联剂、偶氮二异丁腈为引发剂,采用沉淀聚合法制备了莱克多巴胺分子印迹聚合物。试验结果表明:制备的聚合物对印迹分子具有良好的特异选择性。 相似文献
547.
LIU Jinquan HUANG Junli SU Liqiang CAO Xiangyu & JI Ying . School of Municipal Environmental Engineering Harbin Institute of Technology Harbin China . School of Chemistry Chemical Engineering Qiqihar University Qiqihar China 《中国科学B辑(英文版)》2006,49(6):565-572
Polycyclic aromatic hydrocarbons (PAHs) constitute an important group of micropollutants, which are known to be mutagenic, carcinogenic and/or co-carcinogenic and relatively persistent in the environment. The effects of chlorine dioxide (ClO2) on the degradation of anthracene (ANTH), pyrene (PYR) and benzo[a]anthracene (BaA) in aqueous solution were investigated using high performance liquid chromatography (HPLC). In preliminary experiments, it was observed that ClO2 could remove these three PAHs effectively within a short time. Several factors including reaction time, the concentration of ClO2 and pH of the reaction mixture influencing the degradation ratio of PAHs have been studied by batch experiments. The results showed that the degradation ratio of PAHs was affected by reaction time and the concentration of ClO2 instead of pH. The degradation ratio of ANTH, PYR and BaA could reach their maximum as approximately 99.0%, 67.5% and 89.5%, respectively, under the condition as follows: reaction time 30, 60 and 120 min, the concentration of ClO2 0.1, 0.4 and 0.5 mmol·L-1, and pH 7.2. ANTH was selected as the representative to study the reaction mechanism with ClO2. The oxidation products formed in the reaction of ANTH with ClO2 were tentatively identified by gas chromatography-mass spectrometry (GC-MS), and the results showed that the main product was 9, 10-anthraquinone, which could be biodegraded more easily and quickly than ANTH. Through analyzing the reaction properties of ANTH and ClO2, the possible pathway for the ANTH-ClO2 reaction was proposed based on the theory of single electron transfer (SET). 相似文献
548.
549.
La-SO42-/SBA-15 was synthesized with various amounts of lanthanum via incipient-wetness impregnation.Characterization was done by X-ray diffraction(XRD), transmission electron micrographs(TEM), nitrogen adsorption,FTIR spectroscopic analysis, thermogravimetric analysis, and the total amount of acidity of catalyst was estimated by TPD of NH3. The results indicate that lanthanum has been incorporated into SBA-15 molecular sieve. The prepared materials(La-SO42-/SBA-15) keep the highly ordered mesoporous two-dimensional hexagonal structure and do not change the mesoporous channel structure of the support SBA-15. The catalyst showed best catalytic activity in the synthesis of n-butyl acetate. The optimum conditions of the esterification by orthogonal experiments were studied: the molar ratio of n-butanol to acetic acid 1:1.2, the amount of catalyst 7.5%, reaction time 80 min. The yield of n-butyl acetate could reach 93.2% under the optimum conditions. The catalyst was recyclable, cost effective and environmental friendly. 相似文献
550.
离子液体中乙酸异山梨醇酯的合成 总被引:3,自引:0,他引:3
以1-丁基-3-甲基咪唑六氟磷酸盐离子液体为溶剂,对新一代长效抗心绞痛药物单硝酸异山梨酯中间体异山梨醇进行了萃取分离,避免了使用高真空高温蒸馏;以酸性离子液体N-甲基咪唑硫酸氢盐为溶剂和催化剂,合成了中间体2-乙酸异山梨醇酯,产物结构经红外光谱确证.异山梨醇收率80%,2-乙酸异山梨醇酯收率86%. 相似文献