The delineation of the southern boundary of the latitudinal permafrost in the north of China in the period of late Pleistocene, i.e. the last glaciation maximum (LGM), has been hampered for two reasons. Firstly, previ...The delineation of the southern boundary of the latitudinal permafrost in the north of China in the period of late Pleistocene, i.e. the last glaciation maximum (LGM), has been hampered for two reasons. Firstly, previous studies were limited to the eastern part of the north of China, and,secondly, the ages of the permafrost had not been determined systematically. In this paper, we suggest that the southern boundary of the high latitudinal permafrost in the north ofChina is bounded by approximately 38—40N (eastern part) and 37—39N (western part) lines of latitude based on ourinterpretation of periglacial phenomena and their implica-tion to the environment during the late Pleistocene, and this southern boundary is plotted for the first time. Also, we re-construct the migration of the southern latitudinal perma-frost boundary and the environment after LGM. It is pro-posed that two cold stages occurred in the LGM at 26 kaBP and 23—13 kaBP, when the annual mean temperature was 8—12℃ lower than at present.展开更多
目的:研究活化蛋白C(Activated protein C,APC)对大鼠皮瓣缺血再灌注损伤的作用及可能机制。方法:将80只SD雄性大鼠随机分为四组:对照组、药物对照组、模型组和治疗组,每组20只。观察术后72 h内模型大鼠皮瓣形态变化,HE染色观察大鼠皮...目的:研究活化蛋白C(Activated protein C,APC)对大鼠皮瓣缺血再灌注损伤的作用及可能机制。方法:将80只SD雄性大鼠随机分为四组:对照组、药物对照组、模型组和治疗组,每组20只。观察术后72 h内模型大鼠皮瓣形态变化,HE染色观察大鼠皮瓣组织病理学变化,TUNEL法染色观察皮瓣组织细胞凋亡,ELISA法检测血清中TNF-α、IL-6水平,用黄嘌呤氧化酶法和硫代巴比妥酸TBA比色法分别测定皮瓣组织中超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量,Westernblot法检测皮瓣组织中Nrf-2、HO-1、γ-GCS蛋白表达水平。结果:与模型组比较,治疗组皮瓣红肿、坏死程度、病理损伤程度减弱;TUNEL法染色观察,与模型组比较,治疗组皮瓣组织细胞凋亡率减少(P<0.05);ELISA法检测发现,与模型组比较,治疗组血清中TNF-α、IL-6降低(P<0.05);与模型组比较,治疗组SOD活性升高(P<0.05),MDA含量降低(P<0.05);Westernblot法检测发现,与模型组比较,治疗组Nrf-2、HO-1、γ-GCS蛋白相对表达水平上升(P<0.05)。结论:APC能改善大鼠皮瓣缺血再灌注损伤,其机制可能与激活Nrf-2/HO-1信号通路,抑制氧化应激反应和减少细胞凋亡、炎症反应有关。展开更多
文摘The delineation of the southern boundary of the latitudinal permafrost in the north of China in the period of late Pleistocene, i.e. the last glaciation maximum (LGM), has been hampered for two reasons. Firstly, previous studies were limited to the eastern part of the north of China, and,secondly, the ages of the permafrost had not been determined systematically. In this paper, we suggest that the southern boundary of the high latitudinal permafrost in the north ofChina is bounded by approximately 38—40N (eastern part) and 37—39N (western part) lines of latitude based on ourinterpretation of periglacial phenomena and their implica-tion to the environment during the late Pleistocene, and this southern boundary is plotted for the first time. Also, we re-construct the migration of the southern latitudinal perma-frost boundary and the environment after LGM. It is pro-posed that two cold stages occurred in the LGM at 26 kaBP and 23—13 kaBP, when the annual mean temperature was 8—12℃ lower than at present.
文摘目的:研究活化蛋白C(Activated protein C,APC)对大鼠皮瓣缺血再灌注损伤的作用及可能机制。方法:将80只SD雄性大鼠随机分为四组:对照组、药物对照组、模型组和治疗组,每组20只。观察术后72 h内模型大鼠皮瓣形态变化,HE染色观察大鼠皮瓣组织病理学变化,TUNEL法染色观察皮瓣组织细胞凋亡,ELISA法检测血清中TNF-α、IL-6水平,用黄嘌呤氧化酶法和硫代巴比妥酸TBA比色法分别测定皮瓣组织中超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量,Westernblot法检测皮瓣组织中Nrf-2、HO-1、γ-GCS蛋白表达水平。结果:与模型组比较,治疗组皮瓣红肿、坏死程度、病理损伤程度减弱;TUNEL法染色观察,与模型组比较,治疗组皮瓣组织细胞凋亡率减少(P<0.05);ELISA法检测发现,与模型组比较,治疗组血清中TNF-α、IL-6降低(P<0.05);与模型组比较,治疗组SOD活性升高(P<0.05),MDA含量降低(P<0.05);Westernblot法检测发现,与模型组比较,治疗组Nrf-2、HO-1、γ-GCS蛋白相对表达水平上升(P<0.05)。结论:APC能改善大鼠皮瓣缺血再灌注损伤,其机制可能与激活Nrf-2/HO-1信号通路,抑制氧化应激反应和减少细胞凋亡、炎症反应有关。
