目的:“中枢控制器模型”理论主张大脑是运动疲劳的关键调节器,而小脑和基底节为2个主要调定点,该假说为探究运动疲劳的中枢影响机制提供了新的理论基础和研究方向,但受限于研究手段一直无法在人体中得到验证。本研究拟通过功能性磁共...目的:“中枢控制器模型”理论主张大脑是运动疲劳的关键调节器,而小脑和基底节为2个主要调定点,该假说为探究运动疲劳的中枢影响机制提供了新的理论基础和研究方向,但受限于研究手段一直无法在人体中得到验证。本研究拟通过功能性磁共振成像(functional magnetic resonance imaging,fMRI)技术探究与运动疲劳相关的大脑区域以及相应脑区之间的激活与功能连接状态,从而验证人体运动疲劳的“中枢控制器模型”理论。方法:招募20名800 m跑成绩≤2 min 3 s的男性运动员,对其进行最大摄氧量测试,根据测试结果最终遴选出相对最大摄氧量≥55 ml/(kg·min)的11名被试。实验前使用氢质子磁共振波谱(1H-magnetic resonance spectroscopy,1H-MRS)测试被试静息态脑区代谢物质的浓度;使用全脑血氧水平依赖功能磁共振成像(blood oxygen level dependent-functional Magnetic Resonance Imaging,BOLD-fMRI)测试被试静息态脑功能网络连接。随后进行递增负荷运动至疲劳实验,试达到疲劳状态后即刻进行与实验前一致的fMRI测试。结果:通过1H-MRS测试发现,运动疲劳发生后被试左侧基底节区(basal ganglia,BG)的Cho/Cr显著降低(P<0.05);通过BOLD-fMRI发现运动员递增负荷运动至疲劳后小脑(cerebellum)和初级运动区(primary motor areas,M1)、小脑和躯体感觉运动区(sensory motor cortex,SMC)、小脑和海马(hippocampus)/海马旁回(parahippocompalgyrus)之间的功能网络连接程度减弱(P<0.05)。结论:运动疲劳发生后基底节区的代谢物质下降,以小脑为中心的脑功能默认网络连接降低,基底节区和小脑可能是使人体出现运动疲劳状态的重要脑功能区,也初步验证了基底神经节和小脑作为2个监视系统来调控人体产生运动疲劳的“中枢控制器模型”理论假说。展开更多
A speed control analysis for an in-line gasoline fueled internal combustion （IC） engine is presented for the purpose of alleviation of high frequency oscillations in engine revolutions. A dynamic cylinder-by-cylinde...A speed control analysis for an in-line gasoline fueled internal combustion （IC） engine is presented for the purpose of alleviation of high frequency oscillations in engine revolutions. A dynamic cylinder-by-cylinder model is proposed, base on slider-crank mechanism, which is extended to develop a digital governor providing a high fidelity estimation of rotary speed oscillation for hybrid vehicle engines. A modified PID controller that P and I gain is placed in feedback path is also described for hybrid electric vehicle （HEV） engine speed regulation, By comparison between measured and estimated signals, it is demonstrated that a good agreement has been achieved and the governor behaves an excellent damping speed ripple.展开更多
文摘目的:“中枢控制器模型”理论主张大脑是运动疲劳的关键调节器,而小脑和基底节为2个主要调定点,该假说为探究运动疲劳的中枢影响机制提供了新的理论基础和研究方向,但受限于研究手段一直无法在人体中得到验证。本研究拟通过功能性磁共振成像(functional magnetic resonance imaging,fMRI)技术探究与运动疲劳相关的大脑区域以及相应脑区之间的激活与功能连接状态,从而验证人体运动疲劳的“中枢控制器模型”理论。方法:招募20名800 m跑成绩≤2 min 3 s的男性运动员,对其进行最大摄氧量测试,根据测试结果最终遴选出相对最大摄氧量≥55 ml/(kg·min)的11名被试。实验前使用氢质子磁共振波谱(1H-magnetic resonance spectroscopy,1H-MRS)测试被试静息态脑区代谢物质的浓度;使用全脑血氧水平依赖功能磁共振成像(blood oxygen level dependent-functional Magnetic Resonance Imaging,BOLD-fMRI)测试被试静息态脑功能网络连接。随后进行递增负荷运动至疲劳实验,试达到疲劳状态后即刻进行与实验前一致的fMRI测试。结果:通过1H-MRS测试发现,运动疲劳发生后被试左侧基底节区(basal ganglia,BG)的Cho/Cr显著降低(P<0.05);通过BOLD-fMRI发现运动员递增负荷运动至疲劳后小脑(cerebellum)和初级运动区(primary motor areas,M1)、小脑和躯体感觉运动区(sensory motor cortex,SMC)、小脑和海马(hippocampus)/海马旁回(parahippocompalgyrus)之间的功能网络连接程度减弱(P<0.05)。结论:运动疲劳发生后基底节区的代谢物质下降,以小脑为中心的脑功能默认网络连接降低,基底节区和小脑可能是使人体出现运动疲劳状态的重要脑功能区,也初步验证了基底神经节和小脑作为2个监视系统来调控人体产生运动疲劳的“中枢控制器模型”理论假说。
基金This project is supported by National Hi-tech Research and Development Program of China(863 Program, No.2001AA501211).
文摘A speed control analysis for an in-line gasoline fueled internal combustion （IC） engine is presented for the purpose of alleviation of high frequency oscillations in engine revolutions. A dynamic cylinder-by-cylinder model is proposed, base on slider-crank mechanism, which is extended to develop a digital governor providing a high fidelity estimation of rotary speed oscillation for hybrid vehicle engines. A modified PID controller that P and I gain is placed in feedback path is also described for hybrid electric vehicle （HEV） engine speed regulation, By comparison between measured and estimated signals, it is demonstrated that a good agreement has been achieved and the governor behaves an excellent damping speed ripple.
