Protection of salvianolic acid B for human endothelial cells against hydrogen peroxide-induced oxidative damage

Salvianolic acid B(Sal B) is an active component of traditional Chinese medicine Salvia miltiorrhiza and is used to treat vascular diseases. To better understand its mechanism, the antioxidant capacities of Sal B was evaluated with human endothelial cells under oxidative stress. Human endothelial cells were pretreated with Sal B for 12 h followed by hydrogen peroxide for another 12 h. Production of reactive oxygen species (ROS), activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX), and concentration of glu-tathione were measured: Protective effect of Sal B on the endothelial cells from hydrogen peroxide-induced damage ' was observed, and ROS production in the cells was found significantly inhibited. Sal B remarkably enhanced the activities of antioxidant enzymes SOD, CAT and GPX. Furthermore, Sal B up-regulated the intracellular glutathione concentration. The results indicate that Sal B protected endothelial cells from oxidative stress by improving the redox status of the cells through enhancing the antioxidant enzyme activities and increasing the reductive glutathione concentration after the oxidative challenge.     

γ-辐射对α-亚麻酸氧化反应的影响

对α-亚麻酸及其乙酯分别在氧气气氛和氮气气氛下进行一定剂量的γ-辐射，每隔两天测定其过氧化值。研究结果表明：辐射剂量和时间对亚麻酸的过氧化值有较大影响，本文同时探讨了亚麻酸在γ-辐射下过氧化值与反应机制之间的内在联系。     

Reagentless biosensor based on layer-by-layer assembly of functional multiwall carbon nanotubes and enzyme-mediator biocomposite

A simple and controllable layer-by-layer (LBL) assembly method was proposed for the construction of reagentless biosensors based on electrostatic interaction between functional multiwall carbon nanotubes (MWNTs) and enzyme-mediator biocomposites. The carboxylated MWNTs were wrapped with polycations poly(allylamine hydrochloride) (PAH) and the resulting PAH-MWNTs were well dispersed and positively charged. As a water-soluble dye methylene blue (MB) could mix well with horseradish peroxidase (HRP) to form a biocompatible and negativelycharged HRP-MB biocomposite. A (PAH-MWNTs/HRP-MB) _n bionanomultilayer was then prepared by electrostatic LBL assembly of PAH-MWNTs and HRP-MB on a polyelectrolyte precursor film-modified Au electrode. Due to the excellent biocompatibility of HRP-MB biocomposite and the uniform LBL assembly, the immobilized HRP could retain its natural bioactivity and MB could efficiently shuttle electrons between HRP and the electrode. The incorporation of MWNTs in the bionanomultilayer enhanced the surface coverage concentration of the electroactive enzyme and increased the catalytic current response of the electrode. The proposed biosensor displayed a fast response (2 s) to hydrogen peroxide with a low detection limit of 2.0×10⁻⁷ mol/L (S/N=3). This work provided a versatile platform in the further development of reagentless biosensors.     

余甘子抗氧化成分的提取与抗氧化活性研究

以乙醇为溶剂,超声波辅助提取余甘子果实的抗氧化成分并作用于花生油,对提取工艺及提取物对花生油的抗氧化活性进行了研究。正交实验的结果表明最佳提取工艺条件为:固液比为1:20、超声波处理60min、乙醇质量分数为50%;余甘子提取物能明显降低花生油过氧化值,常温下有良好的热稳定性与抗氧化性能。     

铁氰化钴修饰碳糊电极过氧化氢传感器的研究

研究了铁、钴、镍、铜与铋形成的普鲁士蓝及类普鲁士蓝的制备,并将它们用于修饰碳糊电极得到电化学传感器。研究表明：铁氰化钴修饰碳糊电极对H2O2有明显的电催化作用,将它用于H2O2的测定取得较好的结果,测定的线性范围为5．34×10^-6～5．34×10^-4mol·L^-1。该电极具有灵敏度高、稳定性和重现性好等特点。     

过氧化氢氧化苯甲醛合成苯甲酸的研究

在无溶剂、无相转移催化剂条件下,以过渡金属离子作为催化剂,碳酸钠作为碱性添加物,30%过氧化氢作为氧源,在常温搅拌下来催化氧化苯甲醛制备苯甲酸.最佳实验条件为:n(苯甲醛),n(碳酸钠)/n(催化剂),n(过氧化氢)为100:3:0.5:196,反应时间为1h,苯甲酸产率达84.2%.     

磁场方向对碳纳米管氢等离子体微波吸收的影响

深入研究了外加磁场的方向对碳纳米管薄膜中氢等离子体电磁波衰减性能的影响。根据磁离子理论和W．K．B半经典近似法,理论推导了外加静磁场方向和微波传播方向之间的夹角θ为任一值时,碳纳米管薄膜磁化氢等离子体的复介电常数和微波衰减吸收系数公式。在不同条件下数值计算了碳纳米管薄膜中磁化氢等离子体的微波衰减吸收随θ的变化关系。理论结果表明：只要适当调控磁场方向,应用外加静磁场能有效改进碳纳米管氢等离子体的微波衰减吸收性能。通过调节氢等离子体密度、电子有效碰撞频率、外加静磁场的强度和方向,能获得碳纳米管薄膜氢等离子体对某一特定频段微波能的强烈吸收。     

一类新的化学发光反应的研究

报道了酸性过氧化氢在一些金属离子存在时与碱溶液发生的化学发光反应.对影响化学发光的因素以及金属离子的作用进行了试验和讨论.