胆汁酸膜受体Gpbar1在梗阻性黄疸发病机制中的意义与研究进展

Gpbar1是第一个被证实的G蛋白偶联胆汁酸膜受体,其广泛表达于体内肝、胆、肾、肠、神经与心血管系统等.梗阻性黄疸发生时,Gpbar1被胆汁酸信号激活,介导不同的信号转导通路,从而在梗阻性黄疸的发病过程中发挥着相应的病理生理功能.Gpbar1通过控制炎症、调节胆管上皮屏障功能、抑制肾脏氧化应激、调节肠粘膜屏障与肠道菌群、调控瘙痒与感觉障碍、调控心血管功能等,可能是梗阻性黄疸的潜在治疗靶点.本文对Gpbar1在梗阻性黄疸发病机制中的意义与研究进展进行了综述.

Formation mechanism of calcium hexaluminate

To investigate the formation mechanism of calcium hexaluminate（CaAl_（12）O_（19）, CA_6）, the analytically pure alumina and calcia used as raw materials were mixed in CaO/Al_2O_3 ratio of 12.57：137.43 by mass. The raw materials were ball-milled and shaped into green specimens, and fired at 1300-1600°C. Then, the phase composition and microstructure evolution of the fired specimen were studied, and a first principle calculation was performed. The results show that in the reaction system of CaO and Al_2O_3, a small amount of CA_6 forms at 1300°C, and greater amounts are formed at 1400°C and higher temperatures. The reaction is as follows： CaO ·2Al_2O_3（CA_2） ＋ 4Al_2O_3 → CA_6. The diffusions of Ca^（2＋） in CA_2 towards Al_2O_3 and Al^（3＋） in Al_2O_3 towards CA_2 change the structures in different degrees of difficulty. Compared with the difficulty of structural change and the corresponding lattice energy change, it is deduced that the main formation mechanism is the diffusion of Ca^（2＋） in CA_2 towards Al_2O_3.

Artificial intelligence:Emerging player in the diagnosis and treatment of digestive disease

Given the breakthroughs in key technologies,such as image recognition,deep learning and neural networks,artificial intelligence(AI)continues to be increasingly developed,leading to closer and deeper integration with an increasingly data-,knowledge-and brain labor-intensive medical industry.As society continues to advance and individuals become more aware of their health needs,the problems associated with the aging of the population are receiving increasing attention,and there is an urgent demand for improving medical technology,prolonging human life and enhancing health.Digestive system diseases are the most common clinical diseases and are characterized by complex clinical manifestations and a general lack of obvious symptoms in the early stage.Such diseases are very difficult to diagnose and treat.In recent years,the incidence of diseases of the digestive system has increased.As AI applications in the field of health care continue to be developed,AI has begun playing an important role in the diagnosis and treatment of diseases of the digestive system.In this paper,the application of AI in assisted diagnosis and the application and prospects of AI in malignant and benign digestive system diseases are reviewed.

一类时变时滞非线性系统的H_∞参考跟踪控制设计（英文）

目的:针对一类具有时变时滞的非线性系统,设计状态控制器实现闭环系统输出对参考轨迹的H∞跟踪。创新点:利用统一模型表示所研究的时变时滞非线性系统,修正参考模型使其更具一般性,引入缩放系数提高系统的跟踪精度。方法:采用一个由线性时滞动态系统和有界静态非线性项组成的统一模型来描述所要研究的时变时滞非线性系统。完成系统建模后,首先给出参考轨迹跟踪的定义,以修正后的跟踪模型为参考轨迹,采用状态反馈法实现闭环控制(图1)。并对闭环系统的H∞性能进行分析,基于此分析结果推导得到以线性矩阵不等式形式表示的跟踪控制器参数所满足的条件。该条件可以确保闭环系统H∞意义下跟踪给定的参考信号。在控制器设计中引入缩放系数以提高跟踪精度。图2和图4分别给出跟踪控制器对正弦信号和方波信号的H∞跟踪;图3和图5则分别表示在正弦参考信号和方波参考信号输入下,缩放系数的变大对提高跟踪效果的具体影响。结论:针对一类具有时变时滞的非线性系统,以修正后的跟踪模型为参考轨迹,设计状态反馈控制器实现闭环系统输出对参考轨迹的H∞跟踪,并可通过增大缩放系数提高跟踪效果。