为了制备具有远程可控变形且性能优越的形状记忆聚合物,采用巯基-烯点击化学法制备了PCL/CB复合材料,并用FTIR、DSC、1 H NMR和DMA对复合材料的结构、热性能以及形状记忆特性等进行表征。结果表明:交联复合材料薄膜的热转变温度为50℃,...为了制备具有远程可控变形且性能优越的形状记忆聚合物,采用巯基-烯点击化学法制备了PCL/CB复合材料,并用FTIR、DSC、1 H NMR和DMA对复合材料的结构、热性能以及形状记忆特性等进行表征。结果表明:交联复合材料薄膜的热转变温度为50℃,且当预拉伸的复合材料薄膜受到100 mW/cm^(2)强度的激光照射时,CB颗粒吸收激光光子而产生光热转换且由于各向异性链松弛和应变能释放,致使上层薄膜在受到激光照射时,结晶熔融发生形状记忆效应而收缩,与此同时下层薄膜仍然处于玻璃态,上层薄膜的收缩力使PCL/CB复合材料薄膜朝着激光照射方向发生弯曲变形。同时,弯曲角度可以通过薄膜预拉伸应变量、激光照射时间以及薄膜厚度3个参数进行调控;当预拉伸应变为300%、薄膜厚度为0.4 mm时,最大弯曲角为164°。这种具备局部可编程行为的PCL/CB复合薄膜可为光响应SMP的变形模式提供新思路。展开更多
AIM： To investigate the role of major non-protein and protein sulfhydryls and disulfides in chemically induced gastric hemorrhagic mucosal lesions （HML） and the mechanism of gastroprotective effect of sucralfate.ME...AIM： To investigate the role of major non-protein and protein sulfhydryls and disulfides in chemically induced gastric hemorrhagic mucosal lesions （HML） and the mechanism of gastroprotective effect of sucralfate.METHODS： Rats were given 1 mL of 75% ethanol, 25%NaCl, 0.6 mol/L HCI, 0.2 mol/L NaOH or 1% ammonia solutions intragastrically （i.g.） and sacrificed 1, 3, 6 or 12 min later. Total （reduced and oxidized） glutathione （GSH ＋ GSSG）, glutathione disulfide （GSSG）, protein free sulfhydryls （PSH）, protein-glutathione mixed disulfides （PSSG） and protein cystine disulfides （PSSP） were measured in gastric mucosa and liver.RESULTS： Reduced glutathione （GSH） was depleted in the gastric mucosa after ethanol, HCI or NaCl exposure,while oxidized glutathione （GSSG） concentrations increased, except by HCI and NaOH exposure. Decreased levels of PSH after exposure to ethanol were observed,NaCl or NaOH while the total protein disulfides were increased. Ratios of reduced to oxidized glutathione or sulfhydrils to disulfides were decreased by all chemicals.No changes in thiol homeostasis were detected in the liver after i.g. abbreviation should be spelled out the first time here administration of ethanol. Sucralfate increased the concentrations of GSH and PSH and prevented the ethanol-induced changes in gastric mucosal thiol concentrations.CONCLUSION： Our modified methods are now suitable for direct measurements of major protein and nonprotein thiols/disulfides in the gastric mucosa or liver.A common element in the pathogenesis of chemically induced HML and in the mechanism of gastroprotective drugs seems to be the decreased ratios of reduced and oxidized glutathione as well as protein sulfhydryls and disulfides.展开更多
文摘为了制备具有远程可控变形且性能优越的形状记忆聚合物,采用巯基-烯点击化学法制备了PCL/CB复合材料,并用FTIR、DSC、1 H NMR和DMA对复合材料的结构、热性能以及形状记忆特性等进行表征。结果表明:交联复合材料薄膜的热转变温度为50℃,且当预拉伸的复合材料薄膜受到100 mW/cm^(2)强度的激光照射时,CB颗粒吸收激光光子而产生光热转换且由于各向异性链松弛和应变能释放,致使上层薄膜在受到激光照射时,结晶熔融发生形状记忆效应而收缩,与此同时下层薄膜仍然处于玻璃态,上层薄膜的收缩力使PCL/CB复合材料薄膜朝着激光照射方向发生弯曲变形。同时,弯曲角度可以通过薄膜预拉伸应变量、激光照射时间以及薄膜厚度3个参数进行调控;当预拉伸应变为300%、薄膜厚度为0.4 mm时,最大弯曲角为164°。这种具备局部可编程行为的PCL/CB复合薄膜可为光响应SMP的变形模式提供新思路。
文摘AIM： To investigate the role of major non-protein and protein sulfhydryls and disulfides in chemically induced gastric hemorrhagic mucosal lesions （HML） and the mechanism of gastroprotective effect of sucralfate.METHODS： Rats were given 1 mL of 75% ethanol, 25%NaCl, 0.6 mol/L HCI, 0.2 mol/L NaOH or 1% ammonia solutions intragastrically （i.g.） and sacrificed 1, 3, 6 or 12 min later. Total （reduced and oxidized） glutathione （GSH ＋ GSSG）, glutathione disulfide （GSSG）, protein free sulfhydryls （PSH）, protein-glutathione mixed disulfides （PSSG） and protein cystine disulfides （PSSP） were measured in gastric mucosa and liver.RESULTS： Reduced glutathione （GSH） was depleted in the gastric mucosa after ethanol, HCI or NaCl exposure,while oxidized glutathione （GSSG） concentrations increased, except by HCI and NaOH exposure. Decreased levels of PSH after exposure to ethanol were observed,NaCl or NaOH while the total protein disulfides were increased. Ratios of reduced to oxidized glutathione or sulfhydrils to disulfides were decreased by all chemicals.No changes in thiol homeostasis were detected in the liver after i.g. abbreviation should be spelled out the first time here administration of ethanol. Sucralfate increased the concentrations of GSH and PSH and prevented the ethanol-induced changes in gastric mucosal thiol concentrations.CONCLUSION： Our modified methods are now suitable for direct measurements of major protein and nonprotein thiols/disulfides in the gastric mucosa or liver.A common element in the pathogenesis of chemically induced HML and in the mechanism of gastroprotective drugs seems to be the decreased ratios of reduced and oxidized glutathione as well as protein sulfhydryls and disulfides.
