The instability of soil bank slopes induced by freeze-thaw cycles at the northern foot of Tianshan Mountain is very common.The failure not only caused a large amount of soil erosion,but also led to serious reservoir s...The instability of soil bank slopes induced by freeze-thaw cycles at the northern foot of Tianshan Mountain is very common.The failure not only caused a large amount of soil erosion,but also led to serious reservoir sedimentation and water quality degradation,which exerted a lot of adverse effects on agricultural production in the local irrigation areas.Based on field investigations on dozens of irrigation reservoirs there,laboratory tests were carried out to quantitatively analyze the freeze-thaw effect on the soil engineering characteristics to reveal the facilitation on the bank slope instability.The results show that the softening characteristics of the stressstrain curves gradually weaken,the effective cohesions decline exponentially,the seepage coefficients enlarge,and the thermal conductivities decrease after 7 freeze-thaw cycles.The freeze-thaw effect on the specimens with low confining pressures,low dry densities and high water contents is more significant.The water migration and the phase transition between water and ice result in the variations of the soil internal microstructures,which is the main factor affecting the soil engineering characteristics.Sufficient water supply and the alternation of positive and negative temperatures at the reservoir bank slopes in cold regions make the water migration and phase transition in the soil very intensely.It is easy to form a large number of pores and micro cracks in the soil freezing and thawing areas.The volume changes of the soil and the water migration are difficult to reach a dynamic balance in the open system.Long-term freeze-thaw cycles will bring out the fragmentation of the soil particles,resulting in that the micro cracks on the soil surfaces are developing continuously.The soil of the bank slopes will fall or collapse when these cracks penetrate,which often happens in winter there.展开更多
目的探讨心脏死亡器官捐献(donation after cardiac death,DCD)供体质量对肝移植术后受体生存率的影响。方法回顾性分析2018年1月至2021年1月解放军总医院第三医学中心DCD肝移植手术患者100例,移植术后进行为期1年的随访调查,观察肝移...目的探讨心脏死亡器官捐献(donation after cardiac death,DCD)供体质量对肝移植术后受体生存率的影响。方法回顾性分析2018年1月至2021年1月解放军总医院第三医学中心DCD肝移植手术患者100例,移植术后进行为期1年的随访调查,观察肝移植受者的生存状态,对相关危险因素加以分析。结果100例肝移植受者术后1年病死率为3%(3/100),其死亡因素与供体冷缺血时间、供体脂肪肝、术中出血量、供体白蛋白及总胆红素水平、肝细胞水肿密切相关(P<0.05)。多因素Logistic回归分析发现,供体冷缺血时间≥840 min、脂肪肝是影响肝移植受者生存状态的独立危险因素(P<0.05)。肝移植术后感染率为26%(26/100),其肝移植术后感染率与受体肝功能Child-Pugh评分、术前血红蛋白水平、血小板计数、术中输血量、术后重症监护病房(intensive care unit,ICU)留观时间密切相关(P<0.05)。结论DCD供体质量对肝移植术后受体生存率具有显著影响,供体冷缺血时间、供体脂肪肝对肝移植术后受体生存状态具有重要影响。展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2018YFC0809605,2018YFC0809600)the Key Research Program of Frontier Sciences of Chinese Academy of Sciences(Grant No.QYZDY-SSWDQC015)+2 种基金the National Natural Science Foundation of China(Grant No.41230630)the National Science Fund for Distinguished Young Scholars(Grant No.41825015)the Key Research Program of the Chinese Academy of Sciences(Grant No.ZDRW-ZS-2020-1)。
文摘The instability of soil bank slopes induced by freeze-thaw cycles at the northern foot of Tianshan Mountain is very common.The failure not only caused a large amount of soil erosion,but also led to serious reservoir sedimentation and water quality degradation,which exerted a lot of adverse effects on agricultural production in the local irrigation areas.Based on field investigations on dozens of irrigation reservoirs there,laboratory tests were carried out to quantitatively analyze the freeze-thaw effect on the soil engineering characteristics to reveal the facilitation on the bank slope instability.The results show that the softening characteristics of the stressstrain curves gradually weaken,the effective cohesions decline exponentially,the seepage coefficients enlarge,and the thermal conductivities decrease after 7 freeze-thaw cycles.The freeze-thaw effect on the specimens with low confining pressures,low dry densities and high water contents is more significant.The water migration and the phase transition between water and ice result in the variations of the soil internal microstructures,which is the main factor affecting the soil engineering characteristics.Sufficient water supply and the alternation of positive and negative temperatures at the reservoir bank slopes in cold regions make the water migration and phase transition in the soil very intensely.It is easy to form a large number of pores and micro cracks in the soil freezing and thawing areas.The volume changes of the soil and the water migration are difficult to reach a dynamic balance in the open system.Long-term freeze-thaw cycles will bring out the fragmentation of the soil particles,resulting in that the micro cracks on the soil surfaces are developing continuously.The soil of the bank slopes will fall or collapse when these cracks penetrate,which often happens in winter there.
文摘目的探讨心脏死亡器官捐献(donation after cardiac death,DCD)供体质量对肝移植术后受体生存率的影响。方法回顾性分析2018年1月至2021年1月解放军总医院第三医学中心DCD肝移植手术患者100例,移植术后进行为期1年的随访调查,观察肝移植受者的生存状态,对相关危险因素加以分析。结果100例肝移植受者术后1年病死率为3%(3/100),其死亡因素与供体冷缺血时间、供体脂肪肝、术中出血量、供体白蛋白及总胆红素水平、肝细胞水肿密切相关(P<0.05)。多因素Logistic回归分析发现,供体冷缺血时间≥840 min、脂肪肝是影响肝移植受者生存状态的独立危险因素(P<0.05)。肝移植术后感染率为26%(26/100),其肝移植术后感染率与受体肝功能Child-Pugh评分、术前血红蛋白水平、血小板计数、术中输血量、术后重症监护病房(intensive care unit,ICU)留观时间密切相关(P<0.05)。结论DCD供体质量对肝移植术后受体生存率具有显著影响,供体冷缺血时间、供体脂肪肝对肝移植术后受体生存状态具有重要影响。
