目的:建立大鼠肝脏移植急性排斥反应模型并改进其手术技巧,对所建模型进行评价。方法:采用近交系雄性DA大鼠60只,Lewis大鼠120只,分为两组,其中A组30例:Lewis大鼠为供体(n=30),Lewis大鼠为受体;B组60例:DA大鼠为供体(n=60),Lewis大鼠为...目的:建立大鼠肝脏移植急性排斥反应模型并改进其手术技巧,对所建模型进行评价。方法:采用近交系雄性DA大鼠60只,Lewis大鼠120只,分为两组,其中A组30例:Lewis大鼠为供体(n=30),Lewis大鼠为受体;B组60例:DA大鼠为供体(n=60),Lewis大鼠为受体。采用改良“二袖套”法建立肝脏移植模型,观察手术成功率、平均存活时间、术后第1、3、5、7和10 d各时相点血清丙氨酸氨基转移酶(ALT)、总胆红素(TBIL)水平以及移植肝脏的病理学变化。结果:手术成功率为93.3%(84/90);总耗时(90.0±15.0)min;无肝期时间(14.2±2.6)min;平均存活时间A组超过100d,B组(16.2±1.4)d;术后第5 d B组血清ALT和TBIL升高,与A组比较差异非常显著(P<0.01);B组移植肝脏病理检查有明显的排斥反应,而A组没有。结论:DA→LEW(Lewis)大鼠的品系组合是稳定的肝脏移植急性排斥反应模型;通过改进手术技巧提高了手术成功率,为进一步研究提供技术保障。展开更多
This paper presents a disturbance rejection scheme for walking robots under unknown external forces and moments. The disturbance rejection strategy, which combines the inverse dynamics control with the acceleration pr...This paper presents a disturbance rejection scheme for walking robots under unknown external forces and moments. The disturbance rejection strategy, which combines the inverse dynamics control with the acceleration projection onto the ZMP (zero moment point)-plane, can ensure the overall dynamic stability of the robot during tracking the pre-computed trajectories. Under normal conditions, i.e., the system is dynamically balanced, a primary inverse dynamics control is utilized. In the case that the system becomes unbalanced due to external disturbances, the acceleration projection control (APC) loop, will be activated to keep the dynamic stability of the walking robot through modifying the input torques. The preliminary experimental results on a robot leg demonstrate that the proposed method can actually make the robot keep a stable motion under unknown external perturbations.展开更多
短波信道音频干扰分布密集,导致宽带短波探测系统接收信噪比严重恶化。针对传统奇异值分解(Singular value decomposition,SVD)滤波方法损失了干扰频率处的有用功率,对信道参数的高精度提取造成了不利影响。本文深入分析了SVD滤波内部机...短波信道音频干扰分布密集,导致宽带短波探测系统接收信噪比严重恶化。针对传统奇异值分解(Singular value decomposition,SVD)滤波方法损失了干扰频率处的有用功率,对信道参数的高精度提取造成了不利影响。本文深入分析了SVD滤波内部机理,推导得到SVD滤波的解析表达式,并由信号加噪声子空间得出有用功率的鲁棒估计,进而提出了一种新颖的基于功率补偿的音频干扰抑制算法。仿真与实测数据处理结果表明,该算法不仅实现了干扰抑制,而且有效减小了抑制产生的信号损伤,对于短波电离层信道参数的高精度提取具有特殊意义。展开更多
Background Acute rejection remains an important cause of renal allograft dysfunction and the need for accurate diagnosis is essential to successfully treat transplant recipients. The purpose of this study was to deter...Background Acute rejection remains an important cause of renal allograft dysfunction and the need for accurate diagnosis is essential to successfully treat transplant recipients. The purpose of this study was to determine the costimulatory molecules OX40 and OX40L messenger RNA （mRNA） levels in peripheral blood mononuclear cells （PBMCs） to predict acute renal transplant rejection.展开更多
文摘目的:建立大鼠肝脏移植急性排斥反应模型并改进其手术技巧,对所建模型进行评价。方法:采用近交系雄性DA大鼠60只,Lewis大鼠120只,分为两组,其中A组30例:Lewis大鼠为供体(n=30),Lewis大鼠为受体;B组60例:DA大鼠为供体(n=60),Lewis大鼠为受体。采用改良“二袖套”法建立肝脏移植模型,观察手术成功率、平均存活时间、术后第1、3、5、7和10 d各时相点血清丙氨酸氨基转移酶(ALT)、总胆红素(TBIL)水平以及移植肝脏的病理学变化。结果:手术成功率为93.3%(84/90);总耗时(90.0±15.0)min;无肝期时间(14.2±2.6)min;平均存活时间A组超过100d,B组(16.2±1.4)d;术后第5 d B组血清ALT和TBIL升高,与A组比较差异非常显著(P<0.01);B组移植肝脏病理检查有明显的排斥反应,而A组没有。结论:DA→LEW(Lewis)大鼠的品系组合是稳定的肝脏移植急性排斥反应模型;通过改进手术技巧提高了手术成功率,为进一步研究提供技术保障。
文摘This paper presents a disturbance rejection scheme for walking robots under unknown external forces and moments. The disturbance rejection strategy, which combines the inverse dynamics control with the acceleration projection onto the ZMP (zero moment point)-plane, can ensure the overall dynamic stability of the robot during tracking the pre-computed trajectories. Under normal conditions, i.e., the system is dynamically balanced, a primary inverse dynamics control is utilized. In the case that the system becomes unbalanced due to external disturbances, the acceleration projection control (APC) loop, will be activated to keep the dynamic stability of the walking robot through modifying the input torques. The preliminary experimental results on a robot leg demonstrate that the proposed method can actually make the robot keep a stable motion under unknown external perturbations.
文摘短波信道音频干扰分布密集,导致宽带短波探测系统接收信噪比严重恶化。针对传统奇异值分解(Singular value decomposition,SVD)滤波方法损失了干扰频率处的有用功率,对信道参数的高精度提取造成了不利影响。本文深入分析了SVD滤波内部机理,推导得到SVD滤波的解析表达式,并由信号加噪声子空间得出有用功率的鲁棒估计,进而提出了一种新颖的基于功率补偿的音频干扰抑制算法。仿真与实测数据处理结果表明,该算法不仅实现了干扰抑制,而且有效减小了抑制产生的信号损伤,对于短波电离层信道参数的高精度提取具有特殊意义。
文摘Background Acute rejection remains an important cause of renal allograft dysfunction and the need for accurate diagnosis is essential to successfully treat transplant recipients. The purpose of this study was to determine the costimulatory molecules OX40 and OX40L messenger RNA （mRNA） levels in peripheral blood mononuclear cells （PBMCs） to predict acute renal transplant rejection.
