目的探究在紫外线暴露下环指蛋白20(ring finger protein 20,RNF20)低表达对胃癌细胞DNA损伤修复的影响及其相关作用机制。方法实验采用慢病毒载体构建稳定低表达胃癌细胞系,分为对照组和RNF20敲低组,用CCK-8法检测两组细胞的增殖情况,...目的探究在紫外线暴露下环指蛋白20(ring finger protein 20,RNF20)低表达对胃癌细胞DNA损伤修复的影响及其相关作用机制。方法实验采用慢病毒载体构建稳定低表达胃癌细胞系,分为对照组和RNF20敲低组,用CCK-8法检测两组细胞的增殖情况,用总共照射剂量为20 J/m^(2)紫外线照射胃癌MGC803细胞,采用Western blotting及免疫荧光技术检测两组细胞γ-H2AX、RAD51和p21的情况。结果荧光显微镜观察两组细胞均有绿色荧光蛋白表达;CCK-8显示RNF20表达降低会促进胃癌细胞增殖;敲低组细胞中RNF20蛋白较对照组表达降低。与对照组相比,经20 J/m^(2)紫外线照射细胞后,敲低组γ-H2AX消失更加迟缓,RAD51蛋白表达降低,p21蛋白表达下降趋势更慢。结论RNF20敲低会抑制紫外线诱导的胃癌细胞DNA损伤修复过程。展开更多
On 12 May 2008, the magnitude 8.0 Wenchuan Earthquake occurred along the Longmen Shan nappe, Sichuan, China. This devastating earthquake led to a heavy death toll of greater than 80,000. The seismic origin of this ear...On 12 May 2008, the magnitude 8.0 Wenchuan Earthquake occurred along the Longmen Shan nappe, Sichuan, China. This devastating earthquake led to a heavy death toll of greater than 80,000. The seismic origin of this earthquake is currently hotly debated. We suppose that it is a special type of intraplate earthquake called an active-nappe-type earthquake. Using a holistic methodology, incorporating rockmass structure cybernetics and Byerlee's law, we present a comprehensive study on the geological origin of macroseisms in the Longmen Shan area and the seismic origin of the 2008 Wenchuan earthquake. Previous studies of neotectonic activity indicate that the Longmen Shan nappe moves at a rate of 1~3 mm/yr, due to horizontal compressive stress from the Tibetan Plateau. The difference between movement rates in the Bayankala block, Longmen Shan nappe and Sichuan Basin cause slow shear stress and strain accumulation in the Longmen Shan nappe. It is exhibited a relatively simple linear relations for the shear strength and the buried depth of the structural planes, and the detachment layer of the nappe has a higher shearing-sliding strength compared to the overlying fault planes and the underlying ductile shear belts, thus making it more prone to stick-slip deformation. Therefore, the detachment layer was the main section responsible for the Wenchuan earthquake. The initial rupture burst in the detachment layer under the Yingxiu-Beichuan fault, the rupture area nearly 1.4454 × 104 km2,encompassed the cross point of the Yingxiu and the Anxian-Guanxian faults with the detachment layer, then caused the Yingxiu-Beichuan and Anxian-Guanxian faults took an active part in this earthquake, so this earthquake might consist of three chain-like earthquake stages, totally increasing the duration of this earthquake an unusually large amount, to 120 s. The focal depth spanned range of 10-20km,consistent with the observed result of this focal depth by several agencies.展开更多
文摘On 12 May 2008, the magnitude 8.0 Wenchuan Earthquake occurred along the Longmen Shan nappe, Sichuan, China. This devastating earthquake led to a heavy death toll of greater than 80,000. The seismic origin of this earthquake is currently hotly debated. We suppose that it is a special type of intraplate earthquake called an active-nappe-type earthquake. Using a holistic methodology, incorporating rockmass structure cybernetics and Byerlee's law, we present a comprehensive study on the geological origin of macroseisms in the Longmen Shan area and the seismic origin of the 2008 Wenchuan earthquake. Previous studies of neotectonic activity indicate that the Longmen Shan nappe moves at a rate of 1~3 mm/yr, due to horizontal compressive stress from the Tibetan Plateau. The difference between movement rates in the Bayankala block, Longmen Shan nappe and Sichuan Basin cause slow shear stress and strain accumulation in the Longmen Shan nappe. It is exhibited a relatively simple linear relations for the shear strength and the buried depth of the structural planes, and the detachment layer of the nappe has a higher shearing-sliding strength compared to the overlying fault planes and the underlying ductile shear belts, thus making it more prone to stick-slip deformation. Therefore, the detachment layer was the main section responsible for the Wenchuan earthquake. The initial rupture burst in the detachment layer under the Yingxiu-Beichuan fault, the rupture area nearly 1.4454 × 104 km2,encompassed the cross point of the Yingxiu and the Anxian-Guanxian faults with the detachment layer, then caused the Yingxiu-Beichuan and Anxian-Guanxian faults took an active part in this earthquake, so this earthquake might consist of three chain-like earthquake stages, totally increasing the duration of this earthquake an unusually large amount, to 120 s. The focal depth spanned range of 10-20km,consistent with the observed result of this focal depth by several agencies.
