简介:Theapparentsolubility(S),concentration-averagediffusivity(D),andpermeability(P),forC02,CH4andN2throughPPOandaryl-brominatedPPOat35℃forpressurerangingfrom1to26atmarereported.ItisfoundthatP,D,andSofthemembranestoallthethreegasesvarywiththeextentofbromination.Sincreaseswiththeincreaseofthepercentofbromineineachcase,butDtoCO2increasesremarkablyonlyathigherdegreeofbrominafion,andtherefore,PtoCO2isincreasedbymorethan100%overawiderangeofpressureinthecase.Thesolubilitydataarewelldescribedbythedualmodesorptionmodel.ItisfoundthatthegasmoleculessorbedbytheLangmuirmodearerelativelymoreimmobilizedandthecontributionofthenonequilibrinmcharacterofthepolymertogaspermeationincreasesobviouslyforCO2andishardlychangedforCH4withincreasingbrominecontent.Theseobservationsareinterpretedintermsofchangesinspecificfreevolume(SFV)andthecohesiveenergydensity(CED)ofthepolymers.
简介:【目的】研究新型拓扑异构酶Ⅱ抑制剂PPO-1对多种肿瘤细胞株的抑制作用,并初步探讨其作用机制。[方法]MTY法检测PPO-1的体外抗肿瘤活性;光学显微镜观察PPO-1作用后肿瘤细胞形态结构的变化;琼脂糖凝胶电泳分析PPO-1对K562细胞染色体DNA断裂的影响;RT—PCR法检测不同浓度PPO-1(1.0,2.0,4.0μmol/L)对K562细胞caspase-3、topoⅡα/、topoⅡβmRNA表达的影响。【结果】MTT法检测发现PPO-1对多种肿瘤细胞均有较好的活性,IC50为1.41—5.96μmol/L,Giemsa染色发现其出现了典型的凋亡现象,提取总DNA进行琼脂糖凝胶电泳,呈现显著“DNA梯子”,RT—PCR结果显示PPO-1可上调caspase-3及topoⅡdmRNA的表达。【结论】与阳性对照药依托泊苷相比,PPO-1在体外能够抑制多种人源性肿瘤细胞,其抗肿瘤作用机制可能与(1)caspase途径:上调caspase-3基因表达;(2)上调topoⅡα基因表达,抑制topoⅡα催化活性有关。
简介:摘要 目的:富集制备白及抗炎活性部位,测定其抗炎活性。方法:以聚酰胺柱色谱乙醇梯度洗脱法富集白及抗炎活性成分,并采用LPS诱导的RAW264.7巨噬细胞炎症模型测定其抗炎活性。结果:白及醇提取物与聚酰胺按重量比1:4混合,减压浓缩至无醇味,混悬物装柱,20%乙醇洗脱去杂,收集40%乙醇洗脱物,减压干燥得白及药效部位。该药效部位可剂量依赖性抑制LPS诱导的RAW264.7细胞IL-6和TNF-α表达,表现出较好抗炎活性。结论:聚酰胺柱色谱法对白及抗炎活性成分具有较好富集作用,所制备的药效部位具有较强的抗炎活性,这为今后白及开发利用奠定了良好基础。