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淀粉系高吸水性树脂反应中间体稳定性及反应活性的量子化学研究 被引量:6
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作者 颜力楷 兰亚乾 +4 位作者 苏忠民 仇永清 邵琛 李宝利 王荣顺 《高等学校化学学报》 SCIE EI CAS CSCD 北大核心 2003年第2期297-300,共4页
运用 ab initio UHF方法和 DFT UB3LYP方法在 6 -31 G基组水平下对淀粉系高吸水性树脂反应中间体的模型体系进行几何构型优化 .针对每类自由基对应得到的两种典型的构象异构体 ( 1 a,1 b和 2 a,2 b) ,进行稳定性和反应活性分析 .构型 1 ... 运用 ab initio UHF方法和 DFT UB3LYP方法在 6 -31 G基组水平下对淀粉系高吸水性树脂反应中间体的模型体系进行几何构型优化 .针对每类自由基对应得到的两种典型的构象异构体 ( 1 a,1 b和 2 a,2 b) ,进行稳定性和反应活性分析 .构型 1 a和 2 b的总能量相对较低 .比较 4个模型体系的前线分子轨道 ,构型 1 a的能隙较小 ,同时 HOMO能量较高 ,易给出电子 ,LUMO能量较低 ,易得电子 ,有利于电子转移 ,因而有较好的反应活性 .自由基自旋密度主要集聚在 C2或 C3上 ,未有较大弥散 ,同时也是前线 MO主要布居位置和重要的反应活性部位 .对构型 1 a与丙烯酸模型分子形成的复合物分析表明 ,两者的反应未经过过渡态 ,在瞬间即可完成 . 展开更多
关键词 淀粉 反应中间体 稳定性 反应活性 量子化学 高吸水性树脂 自由基 Abinito DFT 几何构型 优化 复合物 核技聚合 丙烯酸
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Down-regulation of STAT3 expression by vector-based small interfering RNA inhibits pancreatic cancer growth 被引量:6
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作者 Chen Huang Guang Yang +3 位作者 Tao Jiang Jun Cao Ke-Jian Huang Zheng-Jun Qiu 《World Journal of Gastroenterology》 SCIE CAS CSCD 2011年第25期2992-3001,共10页
AIM:To evaluate the effect of RNA interference (RNAi) mediated silence of signal transduction and activation of transcription (STAT)3 on the growth of human pancreatic cancer cells both in vitro and in vivo.METHODS:ST... AIM:To evaluate the effect of RNA interference (RNAi) mediated silence of signal transduction and activation of transcription (STAT)3 on the growth of human pancreatic cancer cells both in vitro and in vivo.METHODS:STAT3 specific shRNA was used to silence the expression of STAT3 in pancreatic cancer cell line SW1990.The anti-growth effects of RNAi against STAT3 were studied in vitro and in experimental cancer xenografts in nude mice.The potential pathways involved in STAT3 signaling were detected using reverse transcription polymerase chain reaction and western blotting.RESULTS:The expression of the STAT3 was inhibited using RNAi in SW1990 cells.RNAi against STAT3 inhibited cell proliferation,induced cell apoptosis and significantly reduced the levels of CyclinD1 and Bcl-xL when compared with parental and control vector-transfected cells.In vivo experiments showed that RNAi against STAT3 inhibited the tumorigenicity of SW1990 cells and significantly suppressed tumor growth when it was directly injected into tumors.CONCLUSION:STAT3 signaling pathway plays an important role in the progression of pancreatic cancer,and silence of STAT3 gene using RNAi technique may be a novel therapeutic option for treatment of pancreatic cancer. 展开更多
关键词 Signal transduction and activation of tran-scription 3 RNA interference Pancreatic cancer GROWTH
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Correlation between ^(29)Si polymerization and cementitious activity of coal gangue 被引量:3
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作者 Ji-xiu ZHANG Heng-hu SUN +1 位作者 Yin-ming SUN Na ZHANG 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2009年第9期1334-1340,共7页
A new method for estimating the degree of [SiO4]4-polymerization of coal gangue is presented. The method uses the relative bridging oxygen number (RBO) based on nuclear magnetic resonance (NMR) techniques. X-ray diffr... A new method for estimating the degree of [SiO4]4-polymerization of coal gangue is presented. The method uses the relative bridging oxygen number (RBO) based on nuclear magnetic resonance (NMR) techniques. X-ray diffraction (XRD) and 29Si NMR techniques have been used to study phase transitions and silicate polymerization of coal gangue calcined at different temperatures or co-calcined. It has been found that phase transition of clay minerals causes silicate polymerization to change with temperature. In this study, cementing activity and RBO were determined to be inversely related. Generally, activated coal gangue with lower RBO had better cementitious activity. 展开更多
关键词 Degree of polymerization Relative bridging oxygen number (RBO) Nuclear magnetic resonance (NMR) Coal gangue Cementitious activity
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