With the risk of disappearing for the rock paintings considering long-term exposure in Helan Mountain,the freeze-thaw(F-T)cycling experiments were carried out with 12-hour F-T cycling(0,10,20,30,and 40 F-T cycles)unde...With the risk of disappearing for the rock paintings considering long-term exposure in Helan Mountain,the freeze-thaw(F-T)cycling experiments were carried out with 12-hour F-T cycling(0,10,20,30,and 40 F-T cycles)under five kinds of confining pressures(5,10,20,30,and 40 MPa).The acoustic emission(AE)detect technology was used to reveal the rock fracturing characteristics during the triaxial compression test whole process.The stress-strain relation changes along with different confining pressures and F-T cycles.Peak stress and residual stress changes along with different confining pressures and damages,and the variation of axial stress-AE ringing counts-time changes along with different confining pressures and F-T cycles.The damage variable with AE parameter under F-T and force coupling was defined for the first time,and the damages model was established.The experimental results show that the F-T cycles lead to the decrease of rock strength and the gradual transformation of compression failure mode from brittleness to plasticity.The confining pressure provides a certain ability to resist deformation and inhibit crack growth for rock samples after F-T cycles.The temporal and spatial evolution law of AE counts well corresponds to the loading and failure process of the rock samples.The AE 3D positioning technology can accurately capture the development position and direction of internal cracks and pores of rock,and the failure form is conical shear failure.The established damage model has a better fittingness between the theoretical calculation results and the test results,and is reasonable to be used in the future for protection of Helan Mountain rock painting.展开更多
目的:探讨细胞焦亡在大鼠肺缺血/再灌注(I/R)引发的肝脏损伤中的作用及缺血后处理(I-post-C对其干预的保护机制。方法:将32只SPF级SD雄性大鼠随机分为对照(control)组、I/R组、I/R+I-post-C组及I/R+INF39(细胞焦亡抑制剂)组,每组8只。...目的:探讨细胞焦亡在大鼠肺缺血/再灌注(I/R)引发的肝脏损伤中的作用及缺血后处理(I-post-C对其干预的保护机制。方法:将32只SPF级SD雄性大鼠随机分为对照(control)组、I/R组、I/R+I-post-C组及I/R+INF39(细胞焦亡抑制剂)组,每组8只。普通光镜下观察肝脏组织形态;用相关化学试剂盒测定丙氨酸转氨酶(ALT)、天冬氨酸转氨酶(AST)和caspase-1活性;采用ELISA的方法检测血清中白细胞介素1β(IL-1β)和IL-18水平;使用Western blot及免疫荧光法检测肝组织细胞焦亡相关蛋白的表达情况。结果:与control组相比,I/R组肝小叶结构紊乱,部分肝细胞出现水肿、空泡样变性和坏死,炎症细胞浸润,血清ALT和AST水平显著升高(P<0.01);细胞焦亡相关指标核苷酸结合寡聚化结构域样受体蛋白3(NLRP3)、胱天蛋白酶1(caspase-1)和gasdermin D N端片段(GSDMD-N)蛋白表达增加(P<0.05);NLRP3的免疫荧光表达显著增强(P<0.01);caspase-1活性显著上升(P<0.01);血清中IL-1β和IL-18水平显著升高(P<0.01)。与I/R组相比,I/R+I-post-C组和I/R+INF39组的肝细胞水肿减轻、坏死减少,中央静脉、肝血窦扩张及淤血减轻;大鼠血清ALT和AST水平显著降低(P<0.05);NLRP3免疫荧光表达减弱(P<0.05);细胞焦亡相关指标NLRP3、caspase-1和GSDMD-N的蛋白水平显著降低(P<0.01);血清中IL-1β和IL-18含量显著降低(P<0.01)。结论:I-post-C可通过抑制细胞焦亡减轻大鼠肺I/R引发的肝损伤。展开更多
基金Funded by the National Natural Science Foundation of China(Nos.11662015,51768059 and 51468053)。
文摘With the risk of disappearing for the rock paintings considering long-term exposure in Helan Mountain,the freeze-thaw(F-T)cycling experiments were carried out with 12-hour F-T cycling(0,10,20,30,and 40 F-T cycles)under five kinds of confining pressures(5,10,20,30,and 40 MPa).The acoustic emission(AE)detect technology was used to reveal the rock fracturing characteristics during the triaxial compression test whole process.The stress-strain relation changes along with different confining pressures and F-T cycles.Peak stress and residual stress changes along with different confining pressures and damages,and the variation of axial stress-AE ringing counts-time changes along with different confining pressures and F-T cycles.The damage variable with AE parameter under F-T and force coupling was defined for the first time,and the damages model was established.The experimental results show that the F-T cycles lead to the decrease of rock strength and the gradual transformation of compression failure mode from brittleness to plasticity.The confining pressure provides a certain ability to resist deformation and inhibit crack growth for rock samples after F-T cycles.The temporal and spatial evolution law of AE counts well corresponds to the loading and failure process of the rock samples.The AE 3D positioning technology can accurately capture the development position and direction of internal cracks and pores of rock,and the failure form is conical shear failure.The established damage model has a better fittingness between the theoretical calculation results and the test results,and is reasonable to be used in the future for protection of Helan Mountain rock painting.
文摘目的:探讨细胞焦亡在大鼠肺缺血/再灌注(I/R)引发的肝脏损伤中的作用及缺血后处理(I-post-C对其干预的保护机制。方法:将32只SPF级SD雄性大鼠随机分为对照(control)组、I/R组、I/R+I-post-C组及I/R+INF39(细胞焦亡抑制剂)组,每组8只。普通光镜下观察肝脏组织形态;用相关化学试剂盒测定丙氨酸转氨酶(ALT)、天冬氨酸转氨酶(AST)和caspase-1活性;采用ELISA的方法检测血清中白细胞介素1β(IL-1β)和IL-18水平;使用Western blot及免疫荧光法检测肝组织细胞焦亡相关蛋白的表达情况。结果:与control组相比,I/R组肝小叶结构紊乱,部分肝细胞出现水肿、空泡样变性和坏死,炎症细胞浸润,血清ALT和AST水平显著升高(P<0.01);细胞焦亡相关指标核苷酸结合寡聚化结构域样受体蛋白3(NLRP3)、胱天蛋白酶1(caspase-1)和gasdermin D N端片段(GSDMD-N)蛋白表达增加(P<0.05);NLRP3的免疫荧光表达显著增强(P<0.01);caspase-1活性显著上升(P<0.01);血清中IL-1β和IL-18水平显著升高(P<0.01)。与I/R组相比,I/R+I-post-C组和I/R+INF39组的肝细胞水肿减轻、坏死减少,中央静脉、肝血窦扩张及淤血减轻;大鼠血清ALT和AST水平显著降低(P<0.05);NLRP3免疫荧光表达减弱(P<0.05);细胞焦亡相关指标NLRP3、caspase-1和GSDMD-N的蛋白水平显著降低(P<0.01);血清中IL-1β和IL-18含量显著降低(P<0.01)。结论:I-post-C可通过抑制细胞焦亡减轻大鼠肺I/R引发的肝损伤。
