生物鲁棒性是生物系统抵抗外界扰动或内部参数摄动引起系统行为变化的一种能力。电磁场是一种外界物理因素,可以对生物体产生影响。为了建立一种电磁场扰动下生物系统稳定鲁棒性的研究方法,以Lyapunov理论为基础,用电磁场细胞暴露系统...生物鲁棒性是生物系统抵抗外界扰动或内部参数摄动引起系统行为变化的一种能力。电磁场是一种外界物理因素,可以对生物体产生影响。为了建立一种电磁场扰动下生物系统稳定鲁棒性的研究方法,以Lyapunov理论为基础,用电磁场细胞暴露系统实时记录了在磁感应强度B为0、0.09、0.38、0.76、7.33、14.78 m T的电磁场暴露下细胞内活性氧自由基（ROS）和钙离子（Ca2＋）的含量,分析了电磁场扰动前的细胞状态稳态点和稳定域,以及电磁场扰动后的状态转移和稳定鲁棒域。结果表明：（1）细胞无扰时ROS的稳态点是46.157~120.913,Ca2＋的稳态点是25.430~55.686,ROS的稳定域半径是1.688~10.278,Ca2＋的稳定域半径是2.782~13.345;（2）B〈7.33 m T的电磁场扰动没有提高胞内ROS含量,B为14.78 m T的电磁场扰动可阶跃性提高胞内ROS含量,B为0和0.09 m T的电磁场扰动没有提高胞内Ca2＋含量,B为0.38 m T的电磁场扰动可持续性提高胞内Ca2＋含量。结论是：（1）无电磁场扰动时,细胞内ROS和Ca2＋状态可以保持稳定;（2）电磁场扰动在较高水平（如B为14.78 m T）时,才能改变细胞内ROS和Ca2＋的状态;（3）细胞的鲁棒域与电磁场的磁感应强度无关。展开更多
The super high strength aluminum alloy ingots with 100 mm in diameter were cast by the process of low-frequency electromagnetic horizontal continuous casting (LFEHC) and the effect of electromagnetic field on the as-c...The super high strength aluminum alloy ingots with 100 mm in diameter were cast by the process of low-frequency electromagnetic horizontal continuous casting (LFEHC) and the effect of electromagnetic field on the as-cast microstructure was studied. Results show that microstructure of the sample prepared by the LFEHC process was greatly refined. Microstructures at the border and the center of the ingots were fine, uniform and rosette-shaped. Electromagnetic frequency plays a key role in microstructure refining. Fine and uniform microstructures can be obtained with optimal electromagnetic frequency. In this experiment, under a frequency of 30 Hz the microstructure was the finest and the most uniform.展开更多
目的:研究极低频电磁场(extremely low frequency electromagnetic fields,ELF-EMF)对星形胶质细胞的氧化损伤及莲房原花青素(procyanidins from lotus seedpod,LSPC)的预防作用。方法:以原代培养的SD大鼠星形胶质细胞建立ELF-EMF损伤模...目的:研究极低频电磁场(extremely low frequency electromagnetic fields,ELF-EMF)对星形胶质细胞的氧化损伤及莲房原花青素(procyanidins from lotus seedpod,LSPC)的预防作用。方法:以原代培养的SD大鼠星形胶质细胞建立ELF-EMF损伤模型,检测经LSPC预处理前后的细胞生存率、星形胶质细胞内活性氧(Reactive oxygen species,ROS)、超氧化物歧化酶(Super oxide dismutase,SOD)、丙二醛(MDA)和Ca2+含量。结果:辐射模型组的细胞生存率为54.38%,极显著下降(与正常对照组相比,p<0.01);经5、10、20μg/mLLSPC预处理后,细胞生存率分别为65.09%、75.34%和90.78%,显著上升(与辐射模型组相比,p<0.05);ELF-EMF引起细胞内SOD活力下降,MDA、ROS和Ca2+含量上升,经5、10、20μg/mLLSPC预处理,能有效阻止SOD活力下降并显著抑制MDA、ROS和Ca2+含量的上升(与辐射模型组相比,p<0.05)。结论:LSPC对ELF-EMF导致的星形胶质细胞氧化损伤有明显的预防作用。展开更多
文摘生物鲁棒性是生物系统抵抗外界扰动或内部参数摄动引起系统行为变化的一种能力。电磁场是一种外界物理因素,可以对生物体产生影响。为了建立一种电磁场扰动下生物系统稳定鲁棒性的研究方法,以Lyapunov理论为基础,用电磁场细胞暴露系统实时记录了在磁感应强度B为0、0.09、0.38、0.76、7.33、14.78 m T的电磁场暴露下细胞内活性氧自由基（ROS）和钙离子（Ca2＋）的含量,分析了电磁场扰动前的细胞状态稳态点和稳定域,以及电磁场扰动后的状态转移和稳定鲁棒域。结果表明：（1）细胞无扰时ROS的稳态点是46.157~120.913,Ca2＋的稳态点是25.430~55.686,ROS的稳定域半径是1.688~10.278,Ca2＋的稳定域半径是2.782~13.345;（2）B〈7.33 m T的电磁场扰动没有提高胞内ROS含量,B为14.78 m T的电磁场扰动可阶跃性提高胞内ROS含量,B为0和0.09 m T的电磁场扰动没有提高胞内Ca2＋含量,B为0.38 m T的电磁场扰动可持续性提高胞内Ca2＋含量。结论是：（1）无电磁场扰动时,细胞内ROS和Ca2＋状态可以保持稳定;（2）电磁场扰动在较高水平（如B为14.78 m T）时,才能改变细胞内ROS和Ca2＋的状态;（3）细胞的鲁棒域与电磁场的磁感应强度无关。
基金National "863" project (NO.2001AA332030) of China
文摘The super high strength aluminum alloy ingots with 100 mm in diameter were cast by the process of low-frequency electromagnetic horizontal continuous casting (LFEHC) and the effect of electromagnetic field on the as-cast microstructure was studied. Results show that microstructure of the sample prepared by the LFEHC process was greatly refined. Microstructures at the border and the center of the ingots were fine, uniform and rosette-shaped. Electromagnetic frequency plays a key role in microstructure refining. Fine and uniform microstructures can be obtained with optimal electromagnetic frequency. In this experiment, under a frequency of 30 Hz the microstructure was the finest and the most uniform.
