利用逆转录PCR(RT-PCR)方法与定量逆转录PCR(q RT-PCR)方法对高血脂小鼠脂肪代谢关键基因激素敏感性脂肪酶(hormone-sensitive triglayceride lipase,HSL)、脂肪酸转运蛋白(fatty acid transport protein,FATP)、乙酰辅酶A羧化酶(acetyl...利用逆转录PCR(RT-PCR)方法与定量逆转录PCR(q RT-PCR)方法对高血脂小鼠脂肪代谢关键基因激素敏感性脂肪酶(hormone-sensitive triglayceride lipase,HSL)、脂肪酸转运蛋白(fatty acid transport protein,FATP)、乙酰辅酶A羧化酶(acetyl Co A carboxylase,ACAC)等进行检测,结果表明:喂食小鼠中田大山楂提取物可上调FATP、HSL的表达,抑制脂肪合成的限速酶ACAC的表达.同时,病理切片分析显示,给药剂量为90,mg/(kg·d)、130,mg/(kg·d)的中田大山楂提取物与10,mg/(kg·d)的辛伐他汀均能够显著缓解高脂饲喂所引起的小鼠肝脏病变.为进一步明确中田大山楂提取物对肝脏脂肪变性的保护作用,利用体外培养的人肝癌细胞Hep G2优化,建立了高脂肝细胞模型,油红染色分析表明中田大山楂提取物能够剂量依赖性地直接抑制肝细胞脂肪合成过程.展开更多
To further investigate the microstructure characteristic and solidification mechanism, so as to provide knowledge for the microstructure control of a NiTi-AI based high-temperature structural material, the microstruct...To further investigate the microstructure characteristic and solidification mechanism, so as to provide knowledge for the microstructure control of a NiTi-AI based high-temperature structural material, the microstructure of Ni-43Ti-4AI-2Nb-2Hf （at.%） alloy ingots prepared by conventional casting （arc-melting） and directional solidification （DS） at various drawing velocities （2 mm.min-＇, 18 mm.min-1, 30 mm-min-＇ and 60 mmmin~, respectively） was investigated by means of electron probe microanalyses. Experimental results reveal that the microstructures are composed of NiTi matrix phase,/3-Nb phase and Ti2Ni phase for samples obtained by both conventional casting and DS. Conventional casting has an equiaxial structure, while DS has a slender and acicular cellular structure which grows along the [001] orientation preferentially. Small amounts of white/3-Nb phase and black Ti2Ni phase co-exist at the grain boundaries or intercellular regions. With an increase in drawing velocity, the NiTi matrix phase is inclined to grow along （100） and （200） crystallographic planes, and the cellular arm spacing reduce gradually, but the directionality of the solidified structure weakens significantly. The homogeneous dispersion of,8-Nb phase and the decrease of Ti2Ni phase in DS samples are beneficial to improving the mechanical properties. Solidification mechanism analysis indicates that the dark grey NiTi matrix phase initially precipitates from the liquid phase, and then the divorced eutectic reaction takes place, which produces the light gray matrix phase and/^-Nb phase. Finally, the peritectic reaction happens, which generates the black Ti2Ni phase.展开更多
文摘利用逆转录PCR(RT-PCR)方法与定量逆转录PCR(q RT-PCR)方法对高血脂小鼠脂肪代谢关键基因激素敏感性脂肪酶(hormone-sensitive triglayceride lipase,HSL)、脂肪酸转运蛋白(fatty acid transport protein,FATP)、乙酰辅酶A羧化酶(acetyl Co A carboxylase,ACAC)等进行检测,结果表明:喂食小鼠中田大山楂提取物可上调FATP、HSL的表达,抑制脂肪合成的限速酶ACAC的表达.同时,病理切片分析显示,给药剂量为90,mg/(kg·d)、130,mg/(kg·d)的中田大山楂提取物与10,mg/(kg·d)的辛伐他汀均能够显著缓解高脂饲喂所引起的小鼠肝脏病变.为进一步明确中田大山楂提取物对肝脏脂肪变性的保护作用,利用体外培养的人肝癌细胞Hep G2优化,建立了高脂肝细胞模型,油红染色分析表明中田大山楂提取物能够剂量依赖性地直接抑制肝细胞脂肪合成过程.
基金supported by the Natural Science Foundation of China(Grant No.51101003)
文摘To further investigate the microstructure characteristic and solidification mechanism, so as to provide knowledge for the microstructure control of a NiTi-AI based high-temperature structural material, the microstructure of Ni-43Ti-4AI-2Nb-2Hf （at.%） alloy ingots prepared by conventional casting （arc-melting） and directional solidification （DS） at various drawing velocities （2 mm.min-＇, 18 mm.min-1, 30 mm-min-＇ and 60 mmmin~, respectively） was investigated by means of electron probe microanalyses. Experimental results reveal that the microstructures are composed of NiTi matrix phase,/3-Nb phase and Ti2Ni phase for samples obtained by both conventional casting and DS. Conventional casting has an equiaxial structure, while DS has a slender and acicular cellular structure which grows along the [001] orientation preferentially. Small amounts of white/3-Nb phase and black Ti2Ni phase co-exist at the grain boundaries or intercellular regions. With an increase in drawing velocity, the NiTi matrix phase is inclined to grow along （100） and （200） crystallographic planes, and the cellular arm spacing reduce gradually, but the directionality of the solidified structure weakens significantly. The homogeneous dispersion of,8-Nb phase and the decrease of Ti2Ni phase in DS samples are beneficial to improving the mechanical properties. Solidification mechanism analysis indicates that the dark grey NiTi matrix phase initially precipitates from the liquid phase, and then the divorced eutectic reaction takes place, which produces the light gray matrix phase and/^-Nb phase. Finally, the peritectic reaction happens, which generates the black Ti2Ni phase.
