白藜芦醇与维生素E协同抗氧化效应研究

【目的】研究白藜芦醇(resveratrol,RES)与维生素E联合作用下体外抗氧化作用效果,并探究联合作用下活性成分的协同效应对抗氧化功效的影响。【方法】以特丁基对苯二酚(tertiary butyl hydroquinonentrd,TBHQ)为阳性对照组(TBHQ组),二苯基苦基苯肼(diphenylpicrylhydrazyl,DPPH)、2,2′-偶氮双(3-乙基苯并噻唑啉-6-磺酸)二铵(ABTS)还原力和铁离子还原力(ferric reducing antioxidant power,FRAP)为检测指标,通过半数清除率IC50和中效原理联合作用指数(combination index,CI)对单一使用RES和维生素E的RES组、VE组,以及联合使用的DARV组、ARV组(DARV组的半剂量)的抗氧化效果进行评价。【结果】RES组、VE组、DARV组和ARV组的质量浓度与抗氧化活性呈现显著性相关且具有一定的正协同效应(P<0.05);RES和VE联合后的DARV组IC50值显著降低,小于单一组分RES组和VE组(P<0.05),表明RES和维生素E联合后呈现出协同抗氧化作用,比各组分单一使用时具有更好的抗氧化效果;联合作用时,RES为主剂,维生素E作为辅剂;以DPPH自由基清除率为检测指标,V(RES)∶V(维生素E)=1∶2~1∶3时表现为相加作用(0.95<CI<1.05),V(RES)∶V(维生素E)=1∶1~7∶1之间时具有良好的协同效果(CI<0.95);当V(RES)∶V(维生素E)=3∶1时,IC50为0.011 g·L^(-1),CI<0.95,RES联合维生素E抗氧化作用正协同效应最强。【结论】白藜芦醇与维生素E按照一定体积比例联合使用具有良好的抗氧化协同作用,这有助于活性成分与保健食品及药物联合使用的研发与应用。

EFFECT OF Fe_2O_3 ON WELDING TECHNOLOGY AND MECHANICAL PROPERTIES OF WELD METAL DEPOSITED BY SELF-SHIELDED FLUX CORED WIRE

Five experimental self-shielded flux cored wires are fabricated withdifferent amount of Fe_2O_3 in the flux. The effect of Fe_2O_3 on welding technology and mechanicalproperties of weld metals deposited by these wires are studied. The results show that with theincrease of Fe_2O_3 in the mix, the melting point of the pretreated mix is increased. LiBaF_3 andBaFe_(12)O_(19), which are very low in inherent moisture, are formed after the pretreatment. Themechanical properties are evaluated to the weld metals. The low temperature notch toughness of theweld metals is increased linearly with the Fe_2O_3 content in the flux due to the balance betweenFe_2O_3 and residual Al in the weld metal. The optimum Fe_2O_3 content in flux is 2.5 percent approx3.5 percent.