The diagnostic value of liver stiffness measurement combined with S index in the degree of hepatitis B liver fibrosis

Objective:To investigate the value of liver stiffness measurement(LSM)combined with S index in predicting the degree of liver fibrosis in hepatitis B patients.Methods:A total of 187 chronic hepatitis B patients who were admitted to the Department of Infection,the First Affiliated Hospital of Hainan Medical College from January 2019 to December 2021 were selected.General data were collected,blood routine,liver function,liver fibrosis and liver stiffness measurement were tested,and S index,APRI and FIB-4 index were calculated,and liver biopsy was performed.Results:According to the pathological results of liver puncture,The patients were divided into no significant fibrosis group(n=86),significant fibrosis group(n=71)and cirrhosis group(n=30).There were significant differences in age,PLT,GGT,ALB,S index,HA,LN and LSM levels among the three groups(P<0.05).There was a good correlation between S index and the degree of hepatic fibrosis(rs=0.738,P<0.001).The AUC of S index and LSM for the diagnosis of significant fibrosis in hepatitis B were 0.873 and 0.792,respectively.And the AUC of S index and LSM for the diagnosis of liver cirrhosis were 0.966 and 0.879,respectively.The AUC for the combined diagnosis of significant fibrosis and cirrhosis were 0.908 and 0.988,respectively.The AUROC of combined detection in the diagnosis of cirrhosis was higher than that of LSM,APRI and FIB-4(P<0.05).Conclusion:LSM combined with S index has certain application value in the diagnosis of liver fibrosis/cirrhosis in hepatitis B patients.

Controlling Tendons to Modulate Stiffness of a Planar-to-Spatial Tendon-Driven Continuum Manipulator Under External Uncertain Forces

Continuum manipulators(CM)are soft and flexible manipulators with large numbers of degrees of freedom and can perform complex tasks in an unstructured environment.However,their deformability and compliance can deviate distal tip under uncertain external interactions.To address this challenge,a novel tension-based control scheme has been proposed to modulate the stiffness of a tendon-driven CM,reducing the tip position errors caused by uncertain external forces.To minimize the tip position error,a virtual spring is positioned between the deviated and the desired tip positions.The proposed algorithm corrects the manipulator deviated tip position,improving tension distribution and stiffness profile,resulting in higher stiffness and better performance.The corresponding task space stiffness and condition numbers are also computed under different cases,indicating the effectiveness of the tension control scheme in modulating the manipulator's stiffness.Experimental validation conducted on an in-house developed prototype confirms the practical feasibility of the proposed approach.

Static Stiffness Analysis of a New Type 6-DOF Micro-manipulation Robot

A 6-DOF micro-manipulation robot based on a 3-PPTTRS mechanism is proposed in this paper.Its static stiffness is an important index to evaluate load capacity and positioning accuracy.However,it is insufficient to consider the static stiffness only when the robot is in its initial pose.The stiffness in different positions and poses in its work space must be analyzed also.Thus a method to analyze the relationship between static stiffness and poses in the whole work space is presented.A static stiffness model is proposed first,and the relationship between structural parameters and static stiffness in different poses is discussed.The static stiffness analysis provides foundation for structural parameter design.

一种机构刚度分布方法及在Stewart机构中的应用

并联机构(PKM)通常用于工业加工中的切削或装配,其优良的刚度特性和动态特性对机器人末端精度有了很好的保障。以机构低频共振的振幅为中间量,在机构固有频率振动分析的基础上,采用一阶共振能量分析法,计算机构各连杆刚度分布的比例,建立了一类新的机构刚度(变形能)分布评价指标。该方法用在方案设计阶段,可得到机构的整体刚体分布情况,从而获得了理论层面上的动力学性能依据。最后,以两类典型的Stewart并联机构作为案例,证明了该方法的有效性。

Kinematic and Dynamic Analysis of a 3-■US Spatial Parallel Manipulator

Parallel Kinematic Machines(PKMs)are being widely used for precise applications to achieve complex motions and variable poses for the end effector tool.PKMs are found in medical,assembly and manufacturing industries where accuracy is necessary.It is often desired to have a compact and simple architecture for the robotic mechanism.In this paper,the kinematic and dynamic analysis of a novel 3-PRUS(P:prismatic joint,R:revolute joint,U:universal joint,S:spherical joint)parallel manipulator with a mobile platform having 6 Degree of Freedom(Do F)is explained.The kinematic equations for the proposed spatial parallel mechanism are formulated using the Modified Denavit-Hartenberg(DH)technique considering both active and passive joints.The kinematic equations are used to derive the Jacobian matrix of the mechanism to identify the singular points within the workspace.A Jacobian based sti ness analysis is done to understand the variations in sti ness for different poses of the mobile platform and further,it is used to decide trajectories for the end effector within the singularity free region.The analytical model of the robot dynamics is presented using the Euler-Lagrangian approach with Lagrangian multipliers to include the system constraints.The gravity and inertial forces of all links are considered in the mathematical model.The analytical results of the dynamic model are compared with ADAMS simulation results for a pre-defined trajectory of the end effector.

Kinematic,Workspace and Force Analysis of A Five-DOF Hybrid Manipulator R(2RPR)R/SP+RR

In the present study,the over-constrained hybrid manipulator R(2RPR)R/SP+RR is considered as the research objective.In this paper,kinematics of the hybrid manipulator,including the forward and inverse position,are analyzed.Then,the workspace is checked based on the inverse position solution to evaluate whether the workspace of the hybrid manipulator meets the requirements,and the actual workspace of the hybrid robot is analyzed.After that,the force analysis of the over-constrained parallel mechanism is carried out,and an ADAMS-ANSYS rigid-flexible hybrid body model is established to verify the simulation.Based on the obtained results from the force analysis,the manipulator structure is designed.Then,the structure optimization is carried out to improve the robot stiffness.Finally,calibration and workspace verification experiments are performed on the prototype,cutting experiment of an S-shaped aluminum alloy workpiece is completed,and the experiment verifies the machining ability of the prototype.This work conducts kinematics,workspace,force analyses,structural optimization design and experiments on the over-constrained hybrid manipulator R(2RPR)R/SP+RR,providing design basis and technical support for the development of the novel hybrid manipulator in practical engineering.

Semi-Analytical Approach for Stiffness Estimation of 3-DOF PKM

Due to their advantageous of high stiffness, high speed, large load carrying capacity and complicated surface processing ability, PKMs (Parallel Kinematic Manipulators) have been applied to machine tools. This paper mainly addresses the issue of stiffness formulation of a three-prismatic- revolute-spherical PKM (3-PRS PKM). The manipulators consist of three kinematic limbs of identical topology structure, and each limb is composed of an actuated prismatic-revolute-spherical. In order to build up the stiffness model, kinematics, Jacobian and finite element analysis are also performed as the basis. Main works in this paper can be outlined as follows. By use of approaches of vector, inverse position analysis of 3-PRS PKM is conducted. When the independent position and orientation parameters of the end-effectors are provided, the translational distances of active prismatic joints can be determined. Then with the aid of the wrench and reciprocal screw theory, the overall Jacobian of this manipulator is formulated quickly, and which is a six by six dimensional matrix and can reflect all information about actuation and constraint singularity. After for- mulating the position analysis and Jacobian matrix, the next step is stiffness analysis. Analytical stiffness model, a function of Jacobian matrix and components stiffness matrix, is obtained first using the principle of virtual work. Stiffness model is also a six by six dimensional matrix and can provide the information of actuation and constraint stiffness simultaneously. For the complex geometry shape of some components, it is impossible to know their stiffness distributions with the varying configuration. Therefore, ANSYS technology has to be applied to compute the stiffness coefficients of these components at different configurations. Then, the computed data are used to obtain the stiffness distribution by use of the numerical fitting method. Up to now, the semi-ana- lytical stiffness model of the manipulator is completely formulated and can be applied to estimate the system stiffness of 3-PRS PKM. The model enables the stiffness of a 3-PRS PKM to be quickly estimated. Provided with the geometry parameters and load situation on tool tip, the stiffness of 3-PRS PKM system is estimated based on the stiffness matrix about tool tip which is obtained by transforming the point from the center of circle composed of three S joints to the tool tip. Then, the stiffness of system along x, y and z directions can be solved. In order to testify the correctness, the corresponding stiffness is also obtained by use of FEA software. The stress distribution and fre- quency of system are also gained by solving the FEA model.

Optimization Algorithm for Operation Comfortability of Master Manipulator of Minimally Invasive Surgery Robot

To evaluate the operation comfortability in the master-slave robotic minimally invasive surgery(MIS), an optimal function was built with two operation comfortability decided indices, i.e., the center distance and volume contact ratio. Two verifying experiments on Phantom Desktop and Micro Hand S were conducted. Experimental results show that the operation effect at the optimal relative location is better than that at the random location, which means that the optimal function constructed in this paper is effective in optimizing the operation comfortability.

不同中医证型Wilson病患者肝脏纤维化差异及其与弹性硬度值的关系

目的:探讨不同中医证型Wilson病(WD)患者肝脏硬度值(LSM)及纤维化指标差异及两者的关系。方法:回顾性收集2021年2月至2023年4月住院确诊的110例WD患者的临床资料,中医证型采用指标聚类分析,绘制聚类图。采用简单对应分析中医证型与ADL分级的相关性。比较不同中医证型的一般临床资料、LSM及肝纤维化相关指标,从而探讨LSM与肝纤维化及中医证型分布的关系。结果:WD患者中医证型以湿热内蕴证(59例,53.64%)居多,痰瘀互结证(43例,39.09%)次之,肝肾阴虚证(5例,4.54%)、脾肾阳虚证(3例,2.73%)较少;痰瘀互结证偏向0~Ⅰ级,湿热内蕴证偏向Ⅱ级,肝肾阴虚证偏向Ⅲ~Ⅳ级,脾肾阳虚证在二维投影图中间,并未偏向WD病变程度某一分级;痰瘀互结证、肝肾阴虚证、脾肾阳虚证患者肝脏LSM均高于湿热内蕴证(P<0.05);肝肾阴虚证、脾肾阳虚证患者血清透明质酸(HA)和Ⅳ型胶原(Ⅳ-C)水平高于湿热内蕴证、痰瘀互结证组(P<0.05),4组患者Ⅲ型前胶原氨基端肽(PⅢNP)、层黏连蛋白(LN)水平差异无统计学意义(P>0.05)。湿热内蕴证、痰瘀互结证、肝肾阴虚证中LSM与HA、Ⅳ-C均呈不同程度的正相关。结论:LSM联合血清学指标能更好地评估不同证型WD患者肝纤维化程度。

Kineto-static analysis of a novel high-speed parallel manipulator with rigid-flexible coupled links

A novel high-speed parallel kinematic machine (PKM) named Delta-S parallel manipulator is proposed,which consists of a fixed base connected to a moving platform through three limbs with identical topology.Each limb is composed of one driving arm and one follower arm,herein,the latter includes two strings and one middle rod,all located in a same plane.Compared with similar manipulators with uniform parameters,the novel and unique topology as well as the addition of two strings of Delta-S manipulator can remove the clearance of the spherical joints,reduce the inertial load of components further,improve the positioning accuracy and dynamic performance,and so on.In order to formulate the kineto-static model of Delta-S manipulator,the kineto-static analyses and models of the driving arm,the generalized follower and the moving platform can be carried out by the D'ALEMBERT principle.For the sake of obtaining the force analytic results of strings,the deformation compatibility condition of strings and the middle rod are determined.Furthermore,in virtue of the assumption of small deformation and the linear superposition principle,theminimal pre-tightening force of the strings is calculated.The main results include that the loads of the strings and the middle rod must be larger than "zero" and the pre-tightening force over the workspace must be larger than theminimal pre-tightening force at any time within the workspace,which lay the foundation for the dynamic analysis and the prototype manufacture of the Delta-S manipulator.

GREEN’S FUNCTION AND EFFECTIVE ELASTIC STIFFNESS TENSOR FOR ARBITRARY AGGREGATES OF CUBIC CRYSTALS

A closed but approximate formula of Green’s function for an arbitrary aggregate of cubic crystallites is given to derive the e?ective elastic sti?ness tensor of the polycrystal. This formula, which includes three elastic constants of single cubic crystal and ?ve texture coe?cients, accounts for the e?ects of the orientation distribution function (ODF) up to terms linear in the tex- ture coe?cients. Thus it is expected that our formula would be applicable to arbitrary aggregates with weak texture or to materials such as aluminum whose single crystal has weak anisotropy. Three examples are presented to compare predictions from our formula with those from Nishioka and Lothe’s formula and Synge’s contour integral through numerical integration. As an applica- tion of Green’s function, we brie?y describe the procedure of deriving the e?ective elastic sti?ness tensor for an orthorhombic aggregate of cubic crystallites. The comparison of the computational results given by the ?nite element method and our e?ective elastic sti?ness tensor is made by an example.

A large workspace flexure hinge-based parallel manipulator system

Parallel manipulator systems as promising precision devices are used widely in current researches. A novel large workspace flexure parallel manipulator system utilizing wide-range flexure hinges as passive joints is proposed in this paper, which can attain sub-micron-scale precision over the cubic centimeter motion range. This paper introduces the mechanical system architecture based on the wide-range flexure hinges, analyzes the kinematics via stiffness matrices, presents the control system configuration and control strategy, and finally gives the system performance test results.

基于三次S型速度控制算法的移动机械臂末端振动研究

移动机械臂在实际工作环境中,受其自身柔性特征和外部因素的影响而引起机械臂末端的振动,而速度控制是实现机械臂末端抑振的有效手段之一。以UR10机械臂和Husky移动平台组成的移动机械臂为研究对象,针对梯形和S型速度控制算法的不足,提出一种三次S型速度控制算法,通过建立移动机械臂刚柔耦合动力学的理论和仿真模型得到移动机械臂末端的振动位移曲线和加速度变化曲线,验证了三次S型速度控制算法的正确性和抑振效果的有效性。

基于180s劲度模量的低温开裂指数预测

提出了一种通过材料性能测试,预测5~10年状况下沥青路面实际开裂的方法。依托开裂指数同沥青材料低温性能的关系,利用CAM模型(一种数学模型)拟合得到了5类常用沥青的180 s劲度模量值,预测并提出了PAV(压力老化)状态下各类沥青的开裂指数。通过数据分析,验证了该种模拟方式预测的准确性。借助长吉高速实地芯样开裂情况调研,验证CI值(低温开裂指数)对沥青路面实际开裂水平的预测效果。结果表明,CAM模型下得到的沥青梁180 s模量计算方法简单,数据置信度高,预测得到的SBS改性沥青开裂指数与路面实际开裂水平一致,证明了利用沥青材料性能预测路面实际抗裂能力这一方法的可行性。依据规范提法,给出了五类北方常用沥青的CI值参考区间。

An Adaptive Fuzzy Controller for Trajectory Tracking of Robot Manipulator

In this paper, an adaptive fuzzy control algorithm is proposed for trajectory tracking of an n-DOF robot manipulator subjected to parametric uncertainty and it is advantageous compared to the conventional nonlinear saturation controller. The asymptotic stability of the proposed controller has been derived based on Lyapunaov energy function. The design procedure is straightforward due to its simple fuzzy rules and control strategies. The simulation results show that the present control strategy effectively reduces the control effort with negligible chattering in control torque signals in comparison to the existing nonlinear saturation controller.

Arthroscopic capsular release and manipulation under anaesthesia for frozen shoulders:A hot topic

A frozen shoulder is a common cause of shoulder pain and stiffness.The etiology and pathology of frozen shoulders is not fully understood yet.Frozen shoulderis characterized by a decrease in intra-articular volume and capsular compliance.This can lead to significant limitations in daily life.The majority of the patients can be treated conservatively,with functional recovery to be expected in two to three years.However,if conservative treatment fails,manipulation under anaesthesia and arthroscopic capsular release can both be considered as appropriate treatments.Manipulation is a traditionally well-established technique but in recent years it seems that arthroscopic capsular release has gained popularity.Manipulation is a relative time efficient and technically low-demanding procedure in which the glenohumeral joint is forced into different directions under general anaesthesia to release the capsular contracture,thereby increasing the range of motion of the joint.In arthroscopic capsular release the glenohumeral capsule can be released in a more controlled manner under direct vision.There are no prospective comparative trials available to display superiority of one procedure over the other.In addition,the optimal timing of both these interventions still has to be determined.An overview of the literature concerning this topic and a description of both procedures with its own advantages and disadvantages is provided.

肝硬度值联合S指数对乙型肝炎患者肝纤维化程度的诊断价值

目的:研究肝硬度值(LSM)联合S指数预测乙型肝炎患者的肝纤维化程度。方法:选取2019年1月至2021年12月在海南医学院第一附属医院感染科住院的187例慢性乙型肝炎患者。采集一般资料,进行血常规、肝功能、肝纤维化四项、LSM检测,计算S指数、APRI和FIB-4指数,并进行肝穿刺活检。绘制各模型诊断显著肝纤维化和肝硬化的ROC曲线,比较各模型之间的AUROC。结果:根据肝穿刺病理结果,将患者分为无显著纤维化组(n=86)、显著纤维化组(n=71)、肝硬化组(n=30),3组间年龄、PLT、GGT、ALB、S指数、HA、LN、LSM水平均具有统计学差异(P<0.05)。S指数与肝纤维化程度有较好的相关性(rs=0.738,P<0.001)。S指数和LSM诊断显著纤维化的AUC分别为0.873和0.792,诊断肝硬化的AUC分别为0.966和0.879。两者联合诊断显著纤维化和肝硬化的AUC分别为0.908和0.988。联合检测诊断显著肝纤维化的AUROC显著高于LSM、APRI和FIB-4(P<0.001),但与S指数的AUROC无明显差异(P=0.070)。联合检测诊断肝硬化的AUROC均高于LSM、APRI和FIB-4(P<0.05)。结论:瞬时弹性成像技术联合S指数在乙型肝炎患者肝纤维化/肝硬化的诊断中有一定的应用价值。

慢性乙型肝炎患者肝脏硬度检测和S指数变化及评估肝纤维化程度应用价值探讨

目的探讨慢性乙型肝炎(CHB)患者肝脏硬度检测(LSM)和S指数变化及在评估肝纤维化程度方面的应用价值。方法2020年6月~2022年6月我院收治的CHB患者95例,均接受肝穿刺活检,采用Scheuer System评分系统评估肝组织炎症和纤维化程度。使用超声弹性成像仪行肝脏硬度检测(LSM),使用全自动生化分析仪检测血生化指标,计算S指数。应用SPSS 25.0统计学软件绘制受试者工作特征曲线(ROC),计算曲线下面积(AUC),判断LSM和S指数诊断肝纤维化程度的效能。结果在95例CHB患者中,经肝组织学检查发现非显著性炎症患者66例,显著性炎症者29例及肝纤维化分期S0~S1者62例,S2者19例和S3~S4者14例;显著性炎症CHB患者LSM和S指数分别为(9.6±1.2)kPa和(0.9±0.2),显著高于非显著性炎症CHB患者【分别为(6.7±0.8)kPa和(0.5±0.1),P<0.05】;肝纤维化S3~S4的CHB患者LSM和S指数分别为(11.2±2.3)kPa和(1.1±0.2),显著高于肝纤维化S2的CHB患者【分别为(8.4±1.5)kPa和(0.9±0.2),P<0.05】或肝纤维化S0~S1的CHB患者【分别为(5.7±1.1)kPa和(0.4±0.1),P<0.05】;LSM和S指数诊断显著性肝纤维化的AUC分别为0.891(95%CI:0.811~0.946,P<0.001)和0.889(95%CI:0.808~0.944,P<0.001),其敏感度分别为0.879和0.727,特异度分别为0.807和0.887;LSM和S指数诊断进展期肝纤维化的AUC分别为0.872(95%CI:0.787~0.932,P<0.001)和0.807(95%CI:0.713~0.881,P<0.001),其敏感度均为0.786,特异度分别为0.938和0.765。结论CHB患者LSM和S指数与肝纤维化程度密切相关,监测LSM和S指数变化有助于评估患者肝纤维化程度。

整体模式在郑氏手法治疗肱骨外上髁炎中的临床应用

目的观察郑氏手法治疗肱骨外上髁炎的治疗效果。方法将2021年8月—2022年1月该院筋伤科门诊收治的60例肱骨外上髁炎病人按照纳入顺序用随机数字表随机分类法随机分成两组,每组30例,治疗组30例病人予郑氏手法治疗,对照组30例病人予局部封闭治疗,两组疗程均是2周。疗程结束后评估两组总体疗效,治疗前后视觉模拟评分法(visual analog scale,VAS)评分,治疗前后Mayo肘关节功能评分,治疗前后美国特种外科医院(Hospital for Special Surgery,HSS)肘关节功能评分,治疗前后肘关节局部压痛阈值。结果治疗组的总有效率为88.89%(24/27),优于对照组总有效率81.48%(22/27)(P<0.05);两组治疗后VAS评分均降低,两组差异无统计学意义(P>0.05);两组治疗后Mayo肘关节评分和HSS肘关节评分均增高,治疗组评分明显高于封闭组(P<0.05);两组治疗后Mayo肘关节评分和HSS肘关节评分均增高,治疗组评分明显高于封闭组(P<0.05);两组治疗后肘关节局部压痛阈值较治疗前均有提升,治疗组肘关节局部压痛阈值明显高于封闭组(P<0.05)。结论郑氏手法治疗肱骨外上髁炎疗效优于局部封闭治疗,值得临床推广应用。

郑氏手法结合针刺治疗中老年神经根型颈椎病对其颈椎生理曲度影响的临床观察

目的观察郑氏手法结合针刺治疗中老年神经根型颈椎病的临床疗效及对其颈椎生理曲度的影响。方法将该院2021年6月—2022年5月收治的63例符合神经根型颈椎病急性期诊断标准的患者分为治疗组和对照组,其中治疗组在治疗中脱离2例,完成治疗30例,对照组在治疗中脱离1例,完成治疗30例。治疗组采用郑氏手法结合普通针刺治疗,对照组采用普通手法结合针刺治疗。1周治疗5次,两组均治疗2周。比较两组总体疗效,比较两组治疗前后视觉模拟评分法(visual analogue scale,VAS)、颈椎功能障碍指数(neck disability index,NDI)和颈椎病临床评价量表(clinical evaluation scale of cervical spondylosis,CASCS)评分变化;比较两组治疗前后颈椎生理曲度变化。结果治疗组治疗总有效率为86.67%(26/30),对照组治疗总有效率为63.33%(19/30)。治疗组总体疗效优于对照组(P<0.05);治疗组治疗后VAS评分、NDI评分低于对照组,CASCS评分高于对照组(P<0.05);治疗组治疗后颈椎生理弧度高于对照组(P<0.05)。结论郑氏手法结合针刺是治疗神经根型颈椎病的有效方案,值得临床进一步研究。