研究了一种合成三(乙烯醇)单-11-十一烷基硫醇的新方法,即以三乙二醇和1,11-二溴十一烷为底物,经过去质子化、取代、水解3步反应得到目标化合物三(乙烯醇)单-11-十一烷基硫醇。目标产物的总收率为16.5%,其结构经1 H NMR确证。考察了氢...研究了一种合成三(乙烯醇)单-11-十一烷基硫醇的新方法,即以三乙二醇和1,11-二溴十一烷为底物,经过去质子化、取代、水解3步反应得到目标化合物三(乙烯醇)单-11-十一烷基硫醇。目标产物的总收率为16.5%,其结构经1 H NMR确证。考察了氢化钠用量和水解反应催化剂对产物收率的影响。结果表明,当n(三乙二醇)∶n(氢化钠)=1.00∶1.00时,水解反应催化剂选用浓氨水时,3步反应的收率较高。方法副产物少,污染小,操作简单,适合小批量生产。展开更多
Gamma-ray radiation has always been a convenient and effective way to modify the inter- facial properties in polymer blends. In this work, a small amount of trimethylolpropane triacrylate （TMPTA） was incorporated in...Gamma-ray radiation has always been a convenient and effective way to modify the inter- facial properties in polymer blends. In this work, a small amount of trimethylolpropane triacrylate （TMPTA） was incorporated into poly（ethylene terephthalate） （PET）/random terpolymer elastomer （ST2000） blends by melt-blending. The existence of TMPTA would induce the crosslinking of PET and ST2000 molecular chains at high temperatures of blend- ing, resulting in the improvement in the impact strength but the loss in the tensile strength. When the PET/ST2000 blends were irradiated by gamma-ray radiation, the integrated me- chanical properties could be enhanced significantly at a high absorbed dose. The irradiated sample at a dose of 100 kGy even couldn＇t be broken under the impact test load, and at the same time, has nearly no loss of tensile strength. Based on the analysis of the impact- fractured surface morphologies of the blends, it can be concluded that gamma-ray radiation at high absorbed dose can further in situ enhance the interfacial adhesion by promoting the crosslinking reactions of TMPTA and polymer chains. As a result, the toughness and strength of PET/ST2000 blend could be dramatically improved. This work provides a facial and practical way to the fabrication of polymer blends with high toughness and strength.展开更多
The blood-brain barrier permeability of 20（S） and 20（R）-protopanaxatriol epimers and dammar-20（22）E,24-diene- 313,6α,12β-triol were investigated using the MDCK-pHaMDR cell monolayer model. The bidirectional pe...The blood-brain barrier permeability of 20（S） and 20（R）-protopanaxatriol epimers and dammar-20（22）E,24-diene- 313,6α,12β-triol were investigated using the MDCK-pHaMDR cell monolayer model. The bidirectional permeability tests were carried out, and the apparent permeability coefficients （Papp） were calculated. The two protopanaxatriol epimers showed good permeability with Papp values of-10^-5 cm/s, whereas dammar-20（22）E,24-diene-3β,6α, 12β-triol showed poor permeability with Papp of 〈1 × 10^-7 cm/s. The three compounds showed differences in intracellular accumulations due to their different structures. Inhibition of P-gp with verapamil showed that the transport mechanisms in MDCK-pHaMDR cell monolayer for compounds 1 and 2 epimers were not only simple passive diffusion but also involving an effiux way mediated by P-gp. These findings provided new basis for the further study of compounds 1 and 2 acting on the brain.展开更多
文摘研究了一种合成三(乙烯醇)单-11-十一烷基硫醇的新方法,即以三乙二醇和1,11-二溴十一烷为底物,经过去质子化、取代、水解3步反应得到目标化合物三(乙烯醇)单-11-十一烷基硫醇。目标产物的总收率为16.5%,其结构经1 H NMR确证。考察了氢化钠用量和水解反应催化剂对产物收率的影响。结果表明,当n(三乙二醇)∶n(氢化钠)=1.00∶1.00时,水解反应催化剂选用浓氨水时,3步反应的收率较高。方法副产物少,污染小,操作简单,适合小批量生产。
文摘Gamma-ray radiation has always been a convenient and effective way to modify the inter- facial properties in polymer blends. In this work, a small amount of trimethylolpropane triacrylate （TMPTA） was incorporated into poly（ethylene terephthalate） （PET）/random terpolymer elastomer （ST2000） blends by melt-blending. The existence of TMPTA would induce the crosslinking of PET and ST2000 molecular chains at high temperatures of blend- ing, resulting in the improvement in the impact strength but the loss in the tensile strength. When the PET/ST2000 blends were irradiated by gamma-ray radiation, the integrated me- chanical properties could be enhanced significantly at a high absorbed dose. The irradiated sample at a dose of 100 kGy even couldn＇t be broken under the impact test load, and at the same time, has nearly no loss of tensile strength. Based on the analysis of the impact- fractured surface morphologies of the blends, it can be concluded that gamma-ray radiation at high absorbed dose can further in situ enhance the interfacial adhesion by promoting the crosslinking reactions of TMPTA and polymer chains. As a result, the toughness and strength of PET/ST2000 blend could be dramatically improved. This work provides a facial and practical way to the fabrication of polymer blends with high toughness and strength.
基金The National New Drug R&D Program(Grant No.2011BAI07B082009ZX09301-010)of China
文摘The blood-brain barrier permeability of 20（S） and 20（R）-protopanaxatriol epimers and dammar-20（22）E,24-diene- 313,6α,12β-triol were investigated using the MDCK-pHaMDR cell monolayer model. The bidirectional permeability tests were carried out, and the apparent permeability coefficients （Papp） were calculated. The two protopanaxatriol epimers showed good permeability with Papp values of-10^-5 cm/s, whereas dammar-20（22）E,24-diene-3β,6α, 12β-triol showed poor permeability with Papp of 〈1 × 10^-7 cm/s. The three compounds showed differences in intracellular accumulations due to their different structures. Inhibition of P-gp with verapamil showed that the transport mechanisms in MDCK-pHaMDR cell monolayer for compounds 1 and 2 epimers were not only simple passive diffusion but also involving an effiux way mediated by P-gp. These findings provided new basis for the further study of compounds 1 and 2 acting on the brain.
