内质网是真核细胞中重要的细胞器之一,与维持细胞稳态关系密切。当缺乏葡萄糖、缺氧、体内钙平衡紊乱或者发生氧化应激时,会引起细胞内未折叠蛋白或错误折叠蛋白的积累,导致内质网应激。帕金森病是一种慢性进行性脑变性疾病,典型的病理...内质网是真核细胞中重要的细胞器之一,与维持细胞稳态关系密切。当缺乏葡萄糖、缺氧、体内钙平衡紊乱或者发生氧化应激时,会引起细胞内未折叠蛋白或错误折叠蛋白的积累,导致内质网应激。帕金森病是一种慢性进行性脑变性疾病,典型的病理变化是黑质纹状体多巴胺能神经细胞变性丢失导致的多巴胺神经递质缺乏。目前对帕金森病的治疗多为缓解症状,但不能阻止疾病的进展。通过对内质网应激中的信号通路的研究发现:在帕金森病的发病过程中,多巴胺能神经元的选择性死亡与内质网应激有关。内质网应激过程中的中心调节因子:葡萄糖调节蛋白78(glucose regulated protein 78,GRP78)及其下游ATF4-CHOP-Puma信号通路与帕金森病的发病过程有密切的联系,本文对GRP78及其下游ATF4-CHOP-Puma信号通路近些年来的研究进展进行综述,以期为帕金森病的治疗提供新的靶点和思路。展开更多
Recently, various control methods represented by proportional-integral-derivative （PID） control are used for robotic control. To cope with the requirements for high response and precision, advanced feedforward contr...Recently, various control methods represented by proportional-integral-derivative （PID） control are used for robotic control. To cope with the requirements for high response and precision, advanced feedforward controllers such as gravity compensator, Coriolis/centrifugal force compensator and friction compensators have been built in the controller. Generally, it causes heavy computational load when calculating the compensating value within a short sampling period. In this paper, integrated recurrent neural networks are applied as a feedforward controller for PUMA560 manipulator. The feedforward controller works instead of gravity and Coriolis/centrifugal force compensators. In the learning process of the neural network by using back propagation algorithm, the learning coefficient and gain of sigmoid function are tuned intuitively and empirically according to teaching signals. The tuning is complicated because it is being conducted by trial and error. Especially, when the scale of teaching signal is large, the problem becomes crucial. To cope with the problem which concerns the learning performance, a simple and adaptive learning technique for large scale teaching signals is proposed. The learning techniques and control effectiveness are evaluated through simulations using the dynamic model of PUMA560 manipulator.展开更多
文摘内质网是真核细胞中重要的细胞器之一,与维持细胞稳态关系密切。当缺乏葡萄糖、缺氧、体内钙平衡紊乱或者发生氧化应激时,会引起细胞内未折叠蛋白或错误折叠蛋白的积累,导致内质网应激。帕金森病是一种慢性进行性脑变性疾病,典型的病理变化是黑质纹状体多巴胺能神经细胞变性丢失导致的多巴胺神经递质缺乏。目前对帕金森病的治疗多为缓解症状,但不能阻止疾病的进展。通过对内质网应激中的信号通路的研究发现:在帕金森病的发病过程中,多巴胺能神经元的选择性死亡与内质网应激有关。内质网应激过程中的中心调节因子:葡萄糖调节蛋白78(glucose regulated protein 78,GRP78)及其下游ATF4-CHOP-Puma信号通路与帕金森病的发病过程有密切的联系,本文对GRP78及其下游ATF4-CHOP-Puma信号通路近些年来的研究进展进行综述,以期为帕金森病的治疗提供新的靶点和思路。
基金supported by Grant-in-Aid for Scientific Research(C) (No. 20560248) of Japan
文摘Recently, various control methods represented by proportional-integral-derivative （PID） control are used for robotic control. To cope with the requirements for high response and precision, advanced feedforward controllers such as gravity compensator, Coriolis/centrifugal force compensator and friction compensators have been built in the controller. Generally, it causes heavy computational load when calculating the compensating value within a short sampling period. In this paper, integrated recurrent neural networks are applied as a feedforward controller for PUMA560 manipulator. The feedforward controller works instead of gravity and Coriolis/centrifugal force compensators. In the learning process of the neural network by using back propagation algorithm, the learning coefficient and gain of sigmoid function are tuned intuitively and empirically according to teaching signals. The tuning is complicated because it is being conducted by trial and error. Especially, when the scale of teaching signal is large, the problem becomes crucial. To cope with the problem which concerns the learning performance, a simple and adaptive learning technique for large scale teaching signals is proposed. The learning techniques and control effectiveness are evaluated through simulations using the dynamic model of PUMA560 manipulator.
