检索结果-南通市图书馆

Parkinson’s disease and gut microbiota:from clinical to mechanistic and therapeutic studies

在线全文

学校读者我要写书评

暂无评论

Translational Neurodegeneration 2023年第1期12卷 1-30页

作者： Xuxiang Zhang Beisha Tang jifeng guo Department of Neurology Xiangya HospitalCentral South UniversityChangsha 410008China Key Laboratory of Hunan Province in Neurodegenerative Disorders Central South UniversityChangsha 410008China Hunan International Scientific and Technological Cooperation Base of Neurodegenerative and Neurogenetic Diseases Changsha 410008China Center for Medical Genetics and Hunan Key Laboratory of Medical Genetics School of Life SciencesCentral South UniversityChangsha 410008China Engineering Research Center of Hunan Province in Cognitive Impairment Disorders Central South UniversityChangsha 410008China National Clinical Research Center for Geriatric Disorders Xiangya HospitalCentral South UniversityChangsha 410008China

Parkinson’s disease(PD)is one of the most prevalent neurodegenerative *** typical symptomatology of PD includes motor symptoms;however,a range of nonmotor symptoms,such as intestinal issues,usually occur before the motor *** microorganisms inhabiting the gastrointestinal tract can profoundly influence the physiopathology of the central nervous system through neurological,endocrine,and immune system pathways involved in the microbiota-gut-brain *** addition,extensive evidence suggests that the gut microbiota is strongly associated with *** review summarizes the latest findings on microbial changes in PD and their clinical relevance,describes the underlying mechanisms through which intestinal bacteria may mediate PD,and discusses the correlations between gut microbes and anti-PD *** addition,this review outlines the status of research on microbial therapies for PD and the future directions of PD-gut microbiota research.

关键词： Gut microbiota Microbiota-gut-brain axis Mechanisms Alpha-synuclein Microbial therapy

Study on membrane fouling of submerged membrane bioreactor in treating bathing wastewater

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2008年第10期20卷 1158-1167页

作者： guo jifeng XIA Siqing WANG Rongchang ZHAO Jianfu State Key Laboratory of Pollution Control and Resource Reuse School of Environmental Science and Engineering Tongji University Shanghai 200092 China

A pilot-scale submerged membrane bioreactor (MBR) was used to treat the bathing wastewater for more than 90 d. Several factors a?ecting membrane fouling were studied, including the variation in transmembrane pressure (TMP), changes in extracellular polymeric substance (EPS), and distribution of membrane resistance (R). The relationships between R and EPS concentration were found to be R = 0.00008(EPSS)2.915 in the mixed liquor (EPSS) and R = 0.2853(EPSm) – 0.824 on the membrane surface (EPSm). The constant ...

关键词： MBR membrane fouling extracellular polymeric substance (EPS) PCR-DGGE fluorescent in situ hybridization (FISH)

RNA interference blocking the apoptosis in HEK293 cells induced by overexpression of alpha-synuclein

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2009年第7期4卷 541-546页

作者： Tao Chen Beisha Tang Xiaoping Liao guoqiang Wen Xinxiang Yan jifeng guo Yuhu Zhang Feng Ouyang Zhigang Long Li Cao Jing Li Department of Neurology People's Hospital of Hainan Province Haikou 570311 Hainan Province China Department of Neurology Xiangya Hospital Central South University Changsha 410008 Hunan Province China

BACKGROUND： Overexpression of α-synuclein can induce cell apoptosis. RNA interference （RNAi） may block specific gene function and cause gene silencing. OBJECTIVE： To construct a specific and effective RNAi plasmid for the α-synuclein gene and investigate if RNAi can block apoptosis in HEK293 cells, induced by overexpression of wild-type α-synuclein. DESIGN, TIME AND SETTING： A contrast experiment based on genetically engineered cytobiology was performed at the State Key Lab of Medical Genetics of China, Xiangya Medical College of Central South University, between October 2004 and October 2008. MATERIALS： HEK293 cells and pBSHH1 plasmid were provided by the State Key Lab of Medical Genetics of China; OligDNA sequence by Sagon Bioengineering Company, Shanghai; Lipofectamine 2000 by Invitrogen, USA; α-synuclein monoclonal antibody, Hoechst 33258, and MTT by Sigma, USA; Horseradish peroxidase-coupled goat anti-rat IgG by KPL, USA; FACSan flow cytometry by BD, USA. METHODS： Four target sites were used to construct hairpin RNA pBSHH1 vectors - pSYNi-1, pSYNi-2, pSYNi-3 and pSYNi-4 - which were cloned in the pBSHH1 plasmid. HEK293 cells were transfected using Lipofectamine 2000. In addition, a non-transfect group and a negative plasmid transfect group were established. The cultured HEK293 cells were processed as follows： transfection of blank plasmid （blank control group）, transfection of α-synuclein-pEGFP and RNAi negative vector （negative control group）, and transfection of α-synuclein-pEGFP and pSYNi-1 （transfection group）. Cells in all groups were transfected with Lipofectamine 2000 for 48 hours. MAIN OUTCOME MEASURES： Expression of α-synuclein mRNA and protein were detected by RT-PCR and Western blot. Cell morphology was observed under an inverted fluorescence microscope; cell viability was measured using MTT method; and cell apoptosis was determined with Annexin V-PE flow cytometry. RESULTS： α-synuclein mRNA and protein expressions were significantly decrea

关键词： RNA interference α-synuclein gene apoptosis

Contact mode and force transferring model of cylindrical ultrasonic motor with bending vibration mode

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Acoustics 2008年第4期27卷 330-337页

作者： WANG Jian guo jifeng College of Electrical Engineering Zhejiang University Hangzhou 310027

Cylindrical Ultrasonic Motor （CUSM） can be widely used in many fields such as zoom and focus system of cameras, electric curtain and micro-driver of MEMS. This work concentrates on the single-point and the double-point contact modes between the stator and the rotor, which are proved by theory and experiment. There is a critical point of the pre-pressure. When the pre-pressure is below the critical point, the single-point model is suitable; otherwise the double-point model is appropriate. Then the force transferring model is analyzed, and expressions of mechanical characteristics and efficiency of the motor are put forward. Simulation results are confirmed by experimental ones, which shows that the model is well suited to guide design of the motor. Finally a Ф14 mm prototype was fabricated. Its maximum torque is 0.11 Nm, and the no-load speed is about 300 r/min.

关键词： vibration mode critical point mechanical characteristics Ultrasonic Motor used in

Sequence Planning for On-Orbit Assembly of Large Space Truss Structures in a Multirobot Environment

在线全文

学校读者我要写书评

暂无评论

武汉理工大学学报 2006年第S1期28卷 319-324页

作者： guo jifeng,WANG Ping,CUI Naigang (Deptartment of Astronautic Engineering,Harbin Institute of Technology,Harbin 150001,China) Deptartment of Astronautic Engineering Harbin Institute of TechnologyHarbin 150001China

An approach to sequence planning for on-orbit assembly of large space truss structures in a multirobot environment is presented. A hierarchical representation of large space truss structures at the structural volume element level and strut level is adopted. The representation of connectivity matrix and directed graph is respectively presented at the strut level and SVE level. The multirobot environment that consists of autonomous space robots and struts is supposed. Then the multirobot serial assembly strategy,assembly states,assembly tasks and assembly sequences are described. The assembly sequence planning algorithms at the strut level and SVE level are respectively discussed. The results of the simulations show that this approach is feasible and efficient. Two extensions of this approach include more accurate assessment of the efficiency representation and improvements in planning algorithm. In the future,the assembly sequence planning of more large space truss structures and complex multirobot environments and assembly tasks will be considered.

关键词： assembly planning autonomous space robot large space truss structures.

Implementation of Dijkstra’s Token Circulation on Sensor Network

在线全文

学校读者我要写书评

暂无评论

国际计算机前沿大会会议论文集 2015年第1期 40-41页

作者： Zhiqiang Ma Achuan Wang jifeng guo Northeast forestry university HeilongjiangHarbin China

Sensor networks can consist of large number of sensors. Often, sensors networks use low cost units and thus a subject to malfunctions that can bring the system to inconsistent states. After deployment, the system can be situated in places that are hard to reach and therefore manual reboot operations are undesirable and even unfeasible. Therefore, it is imperative to consider the eventual recovery of arbitrary fault when designing sensor networks. Dijkstra’s algorithm is an important foundation of self-managing computer system and fault-tolerance computing system in distributed systems, since it allows a distributed system to recover from arbitrary starting state within a finite time. The arbitrary starting state ca model arbitrary failure (as long as the code segment stays correct).Another key advantage of Dijkstra’s asynchronous algorithm is that no global clock is needed. This project tests an implementation of Dijkstra’s algorithm using snapshotting techniques that we developed in an earlier work. These sensors can initiate from any state but they come into a consistent one after several cycles of running. We demonstrate the usefulness of our testing technique.

关键词： Dijkstra’s algorithm Sensor network consistent state

一种中空短柱径向-扭转振动复合型超声波电动机

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

电工技术学报 2009年第10期24卷 6-11页

作者：王剑郭吉丰浙江大学电气工程学院杭州310027

纵扭复合型超声波电动机比其他类型的超声波电动机更具低速大力矩的特点,可实现高精度直接驱动,可作伺服电动机使用,适合于多种场合,特别是航空航天等军事领域。由于纵、扭振动在定子中的传播速度不一样,其纵、扭两相谐振频率的调谐一... 详细信息

纵扭复合型超声波电动机比其他类型的超声波电动机更具低速大力矩的特点,可实现高精度直接驱动,可作伺服电动机使用,适合于多种场合,特别是航空航天等军事领域。由于纵、扭振动在定子中的传播速度不一样,其纵、扭两相谐振频率的调谐一直是个难题。本文提出了一种新型的径向-扭转复合型超声波电动机,利用了定子径向振动时因泊松效应产生的纵向振动,其实质是径向振动和扭转振动的复合,是一种变形了的纵扭复合型超声波电动机。其定子具有中空、短柱等特点,可方便实现一阶径向振动与一阶扭转振动谐振频率的调谐及其结构等的优化。文中给出了中空短柱的电动机定子结构,建立了径向振动的理论分析模型,分析了其调谐原理和过程,并结合ANSYS有限元计算实现定子结构优化设计。最后根据上述理论研制了Φ60mm的样机,实现的样机性能较好,其空载转速为25r/min,堵转力矩为5N·m。这种超声波电动机较以往电动机具有轴向尺寸小、重量轻和无噪声等优点。

关键词：超声波电动机径向-扭转复合型振子调谐中空结构短柱结构

EKF based Multiple-Mode Attitude Estimator for Quadrotor Using Inertial Measurement Unit

在线全文

学校读者我要写书评

暂无评论

EKF based Multiple-Mode Attitude Estimator for Quadrotor Usi...

第36届中国控制会议

作者： Yingfu Xu jifeng guo Yingzi Guan Harbin Institute of Technology

A novel switchable multiple-mode sensor fusion algorithm for attitude estimation of quadrotor is proposed in this *** is a robust algorithm which shows good performance in flight conditions where sustained translational acceleration and wind disturbance *** algorithm is based on quaternion-based extended Kalman filter（EKF） in direct configuration and uses measurements from a strap-down MEMS IMU equipped with 3-axis gyroscope and 3-axis *** on a high-fidelity dynamic model of quadrotor,a new measurement model is proposed for flight conditions with translational *** order to use sensor data appropriately in different flight conditions,a decision tree is designed as a switching strategy to divide the fusion process into three modes and switch the estimator between them according to the outputs of the IMU and the innovation *** is demonstrated by simulation and experiment that the proposed algorithm can maintain accurate estimation of the quadrotor’s attitude even under the effect of sustained translational acceleration and wind disturbance,which lead to poor performance of traditional algorithms which assume that 3-axis accelerometer measures the gravity vector.

关键词： Quadrotor Attitude Estimation Inertial Measurement Unit(IMU) Mode Switching Extended Kalman Filter

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

数字滤波器及电感补偿算法在PFC中的应用

电力自动化设备 2012年第9期32卷 90-94页

作者：郭晓瑞郭吉丰浙江大学电气工程学院浙江杭州310027

传统PFC控制器设计方案中,输入电流的THD主要取决于PFC控制器的控制性能及输入市电电压的质量。针对直流母线电压纹波对PFC控制性能的影响,提出一种新型的数字滤波器,对母线电压误差中的交流分量进行检测及滤除,有效地抑制了直流母线电... 详细信息

传统PFC控制器设计方案中,输入电流的THD主要取决于PFC控制器的控制性能及输入市电电压的质量。针对直流母线电压纹波对PFC控制性能的影响,提出一种新型的数字滤波器,对母线电压误差中的交流分量进行检测及滤除,有效地抑制了直流母线电压纹波对PFC电压环控制器的干扰,使控制器在保持母线电压稳定的同时,其输出的控制量近似趋近平直,从而极大地降低电流环电感电流参考值的畸变率,可以有效地降低输入电流的THD。针对电流环中电感值随电流变化的特点,在PFC电流环中加入电感补偿以提高电流环的追踪性能。最后实验结果验证了所提数字滤波器和电感补偿算法的可行性。

关键词：功率因数校正谐波分析 THD 数字滤波器补偿