A moderate stress such as cold water swimming can raise the tolerance of the body to potentially injurious events. However, little is known about the mechanism of beneficial effects induced by moderate stress. In this...A moderate stress such as cold water swimming can raise the tolerance of the body to potentially injurious events. However, little is known about the mechanism of beneficial effects induced by moderate stress. In this study, we used a classic rat model of traumatic brain injury to test the hypothesis that cold water swimming preconditioning improved the recovery of cognitive functions and explored the mechanisms. Results showed that after traumatic brain injury, pre-conditioned rats（cold water swimming for 3 minutes at 4℃） spent a significantly higher percent of times in the goal quadrant of cold water swim, and escape latencies were shorter than for non-pretreated rats. The number of circulating endothelial progenitor cells was significantly higher in pre-conditioned rats than those without pretreatment at 0, 3, 6 and 24 hours after traumatic brain injury. Immunohistochemical staining and Von Willebrand factor staining demonstrated that the number of CD34~＋ stem cells and new blood vessels in the injured hippocampus tissue increased significantly in pre-conditioned rats. These data suggest that pretreatment with cold water swimming could promote the proliferation of endothelial progenitor cells and angiogenesis in the peripheral blood and hippocampus. It also ameliorated cognitive deficits caused by experimental traumatic brain injury.展开更多
冷绝缘高温超导(cold dielectric high temperature superconducting,CD HTS)电缆在电力系统输电运行中,不可避免地会受到故障电流的冲击。在故障持续时间内,超导电缆产生大量热量,导致温度升高,从而使超导电缆由超导态向正常态转变,对...冷绝缘高温超导(cold dielectric high temperature superconducting,CD HTS)电缆在电力系统输电运行中,不可避免地会受到故障电流的冲击。在故障持续时间内,超导电缆产生大量热量,导致温度升高,从而使超导电缆由超导态向正常态转变,对超导电缆载流性能产生影响。通过建立故障电流下超导电缆等效电路模型与热传导模型,提出了超导电缆在故障电流冲击时的各层电流瞬态分布解析算法,通过耦合电磁计算与传热分析模型,提出了超导电缆故障电流冲击下的温度分布数值计算法。最后,对110 k V/3 k A冷绝缘高温超导电缆在25 k A、持续3 s故障电流冲击时的电流分布和温度分布情况进行了计算分析。结果表明:在故障时间内,伴随导体层温度逐渐上升,各个导体层电流呈下降趋势,各层的温度在92 K前后上升速率不再相同,铜骨架承受近96%的故障电流,分流作用明显。分析结果为设计故障电流冲击下超导电缆的故障保护策略提供了参考依据,对保障超导电缆的稳定运行具有指导意义。展开更多
基金supported by a grant from the Incubation Project of Natural Science Foundation of Tianjin Medical University General Hospital in China,No.303071901401the Natural Science Foundation of Tianjin of China,No.13JCZDJC30800the National Natural Science Foundation of China,No.81271361 and 81330029
文摘A moderate stress such as cold water swimming can raise the tolerance of the body to potentially injurious events. However, little is known about the mechanism of beneficial effects induced by moderate stress. In this study, we used a classic rat model of traumatic brain injury to test the hypothesis that cold water swimming preconditioning improved the recovery of cognitive functions and explored the mechanisms. Results showed that after traumatic brain injury, pre-conditioned rats（cold water swimming for 3 minutes at 4℃） spent a significantly higher percent of times in the goal quadrant of cold water swim, and escape latencies were shorter than for non-pretreated rats. The number of circulating endothelial progenitor cells was significantly higher in pre-conditioned rats than those without pretreatment at 0, 3, 6 and 24 hours after traumatic brain injury. Immunohistochemical staining and Von Willebrand factor staining demonstrated that the number of CD34~＋ stem cells and new blood vessels in the injured hippocampus tissue increased significantly in pre-conditioned rats. These data suggest that pretreatment with cold water swimming could promote the proliferation of endothelial progenitor cells and angiogenesis in the peripheral blood and hippocampus. It also ameliorated cognitive deficits caused by experimental traumatic brain injury.
基金国家自然科学青年基金项目(51207146)国家电网公司科技项目(DG71-11-009)+1 种基金The Royal Academy of Engineering International exchange SchemeUK(EE1053)~~
文摘冷绝缘高温超导(cold dielectric high temperature superconducting,CD HTS)电缆在电力系统输电运行中,不可避免地会受到故障电流的冲击。在故障持续时间内,超导电缆产生大量热量,导致温度升高,从而使超导电缆由超导态向正常态转变,对超导电缆载流性能产生影响。通过建立故障电流下超导电缆等效电路模型与热传导模型,提出了超导电缆在故障电流冲击时的各层电流瞬态分布解析算法,通过耦合电磁计算与传热分析模型,提出了超导电缆故障电流冲击下的温度分布数值计算法。最后,对110 k V/3 k A冷绝缘高温超导电缆在25 k A、持续3 s故障电流冲击时的电流分布和温度分布情况进行了计算分析。结果表明:在故障时间内,伴随导体层温度逐渐上升,各个导体层电流呈下降趋势,各层的温度在92 K前后上升速率不再相同,铜骨架承受近96%的故障电流,分流作用明显。分析结果为设计故障电流冲击下超导电缆的故障保护策略提供了参考依据,对保障超导电缆的稳定运行具有指导意义。
