In this study, we investigated alterations in the resting-state functional connectivity of the prefrontal cortex in chronic heroin abusers using functional magnetic resonance imaging. We found that, compared with norm...In this study, we investigated alterations in the resting-state functional connectivity of the prefrontal cortex in chronic heroin abusers using functional magnetic resonance imaging. We found that, compared with normal controls, in heroin abusers the left prefrontal cortex showed decreased functional connectivity with the left hippocampus, right anterior cingulate, left middle frontal gyrus, right middle frontal gyrus and right precuneus. However, the right prefrontal cortex showed decreased functional connectivity with the left orbital frontal cortex and the left middle frontal gyrus in chronic heroin abusers. These alterations of resting-state functional connectivity in the prefrontal cortices of heroin abusers suggest that their frontal executive neural network may be impaired, and that this may contribute to their continued heroin abuse and relapse after withdrawal.展开更多
We propose a distributed closedloop power control scheme for a cognitive radio network(CRN) based on our developed state space model of the CRN. The whole power control process is separated into outer control loop and...We propose a distributed closedloop power control scheme for a cognitive radio network(CRN) based on our developed state space model of the CRN. The whole power control process is separated into outer control loop and inner control loop in order to solve different problem. In outer loop, the interference temperature(IT) constraint is transformed to a performance index minimized by a state feedback controller to obtain an appropriate target signal to interference plus noise ratio(SINR) of secondary user(SU). For ideal channel model and random time-varying channel model, our designed controller is a linear quadratic regulator(LQR) and a linear quadratic Gaussian(LQG) regulator respectively. While in inner loop, SU controls its transmit power to make the instantaneous SINR track the corresponding target and ensure the IT constraint under the limited threshold. The closed-loop stability of the CRN is proved and the performance of proposed control scheme is presented by computer simulations, which shows that this scheme can effectively guarantee both the requirement of SINR and IT constraint for all SUs.展开更多
目的观察控制性降压的实施与引起术后认知功能障碍（POCD）的联系。方法将60例ASAⅠ-Ⅱ级、年龄大于60岁、中学及以上文化程度的行择期脊柱手术的患者。随机分为3组,控制性降压Ⅰ、Ⅱ组及非降压组,每组20例,控制性降压Ⅰ组平均动脉压（...目的观察控制性降压的实施与引起术后认知功能障碍（POCD）的联系。方法将60例ASAⅠ-Ⅱ级、年龄大于60岁、中学及以上文化程度的行择期脊柱手术的患者。随机分为3组,控制性降压Ⅰ、Ⅱ组及非降压组,每组20例,控制性降压Ⅰ组平均动脉压（MAP）70-80 mm Hg,Ⅱ组MAP80-85 mm Hg。麻醉前均不用术前药,静脉注射异丙酚、芬太尼、维库溴铵快速诱导气管插管,机械通气,维持呼气末二氧化碳分压在正常范围,麻醉用异丙酚和瑞芬太尼维持,术中定时追加维库溴铵。术中连续监测心率（HR）、MAP,脉搏血氧饱和度（SpO2）。应用简易智力状态检查（MMSE）测试方法调查患者术前和术后1 h、24h、4 d的认知功能变化。结果术后共有25例发生POCD。非降压组与降压Ⅰ、Ⅱ组术后1 h MMSE评分比较,差异有统计学意义（P〈0.01）。降压Ⅰ、Ⅱ组术后24 h MMSE评分两两比较,差异有统计学意义（P〈0.05）。MMSE计算力、近期记忆力评分在术后24 h、术后4 d,非降压组与降压Ⅰ组和Ⅱ组差异有统计学意义（P〈0.05）。结论控制性降压影响老年人POCD,以近期记忆力、计算力影响为甚,且降压程度越大发生POCD的概率越大。展开更多
基金the National Natural Science Foundation of China,No.30973084
文摘In this study, we investigated alterations in the resting-state functional connectivity of the prefrontal cortex in chronic heroin abusers using functional magnetic resonance imaging. We found that, compared with normal controls, in heroin abusers the left prefrontal cortex showed decreased functional connectivity with the left hippocampus, right anterior cingulate, left middle frontal gyrus, right middle frontal gyrus and right precuneus. However, the right prefrontal cortex showed decreased functional connectivity with the left orbital frontal cortex and the left middle frontal gyrus in chronic heroin abusers. These alterations of resting-state functional connectivity in the prefrontal cortices of heroin abusers suggest that their frontal executive neural network may be impaired, and that this may contribute to their continued heroin abuse and relapse after withdrawal.
基金supported by the National Natural Science Foundation of China (Grant No. 61571209)
文摘We propose a distributed closedloop power control scheme for a cognitive radio network(CRN) based on our developed state space model of the CRN. The whole power control process is separated into outer control loop and inner control loop in order to solve different problem. In outer loop, the interference temperature(IT) constraint is transformed to a performance index minimized by a state feedback controller to obtain an appropriate target signal to interference plus noise ratio(SINR) of secondary user(SU). For ideal channel model and random time-varying channel model, our designed controller is a linear quadratic regulator(LQR) and a linear quadratic Gaussian(LQG) regulator respectively. While in inner loop, SU controls its transmit power to make the instantaneous SINR track the corresponding target and ensure the IT constraint under the limited threshold. The closed-loop stability of the CRN is proved and the performance of proposed control scheme is presented by computer simulations, which shows that this scheme can effectively guarantee both the requirement of SINR and IT constraint for all SUs.
文摘目的观察控制性降压的实施与引起术后认知功能障碍（POCD）的联系。方法将60例ASAⅠ-Ⅱ级、年龄大于60岁、中学及以上文化程度的行择期脊柱手术的患者。随机分为3组,控制性降压Ⅰ、Ⅱ组及非降压组,每组20例,控制性降压Ⅰ组平均动脉压（MAP）70-80 mm Hg,Ⅱ组MAP80-85 mm Hg。麻醉前均不用术前药,静脉注射异丙酚、芬太尼、维库溴铵快速诱导气管插管,机械通气,维持呼气末二氧化碳分压在正常范围,麻醉用异丙酚和瑞芬太尼维持,术中定时追加维库溴铵。术中连续监测心率（HR）、MAP,脉搏血氧饱和度（SpO2）。应用简易智力状态检查（MMSE）测试方法调查患者术前和术后1 h、24h、4 d的认知功能变化。结果术后共有25例发生POCD。非降压组与降压Ⅰ、Ⅱ组术后1 h MMSE评分比较,差异有统计学意义（P〈0.01）。降压Ⅰ、Ⅱ组术后24 h MMSE评分两两比较,差异有统计学意义（P〈0.05）。MMSE计算力、近期记忆力评分在术后24 h、术后4 d,非降压组与降压Ⅰ组和Ⅱ组差异有统计学意义（P〈0.05）。结论控制性降压影响老年人POCD,以近期记忆力、计算力影响为甚,且降压程度越大发生POCD的概率越大。
