踝关节位置觉和肌肉力觉的重测信度

背景:目前对于踝关节矢状面内本体感觉的研究较为缺乏,踝关节本体感觉的测试没有统一的标准。目的:分析踝关节矢状面内运动位置觉和力觉的重测信度。方法:踝关节位置觉采用对踝关节跖屈5°的被动定位被动复位能力进行测试,肌肉力觉采用受试者踝关节对跖屈肌群25%最大等长峰值力矩值的复制能力进行测试;运用组内相关系数和测量的标准误来判断位置觉和力觉重复测量结果的一致性程度。结果与结论:用来衡量关节位置觉和肌肉力觉的可变误差和绝对误差的组内相关系数均大于0.75,而且测量的标准误相对较小。常数误差的组内相关系数均小于0.75,而且测量的标准误相对较大。提示用来衡量位置觉和力觉的常数误差重测信度较差,用来衡量位置觉和力觉的可变误差和绝对误差重测信度较好。     

不同目标力矩时距小腿关节肌肉力觉的重测信度**☆

背景：目前对于距小腿关节矢状面内肌肉力觉的研究较为缺乏,距小腿关节肌肉力觉的测试没有统一的标准。 目的：通过分析不同目标力矩时距小腿关节矢状面内运动肌肉力觉的重测信度,探讨距小腿关节肌肉力觉的测量方法。 方法：选取跖屈肌群最大等长峰值力矩值的25%,50%和75%作为距小腿关节肌肉力觉的目标力矩值,测试距小腿关节肌肉对这些目标力矩值的复制能力;运用组内相关系数和测量的标准误来判断肌肉力觉的重复测量结果的一致性程度。 结果与结论：结果显示用来衡量关节肌肉力觉的可变误差和绝对误差的组内相关系数均大于0.75,而且测量的标准误相对较小;常数误差的组内相关系数均小于0.75,而且测量的标准误相对较大。在目标力矩较小时,用来衡量肌肉力觉的可变误差和绝对误差重测信度较好。     

眼膜组织厚度模型化及非接触式测量系统的研究

设计了眼膜组织的模型,并根据眼膜组织的物理特性进行模型化。研制了一种基于光纤位移传感器的非接触式眼膜组织厚度检测系统。通过实验测得模型厚度为2.086mm,与实际厚度(2.5mm)有0.414mm误差。非接触式测量系统为眼膜组织厚度提供了一种新的有效测量手段。     

传声媒质对双界面回波法测量精度的影响

目的 双界面回波法（dual-boundary echo comparison,DBEC）是一种有望实现血液超声衰减系数（ultrasonic attenuation coefficient,USAC）无损测量的新方法.使用该方法需要预先测试探头的校正系数,该值反映了声束形状.若将在水中获得的校正系数应用到非水媒质中会带来测量误差,本文通过实验研究这种误差的范围、影响因素以及减小误差的方法.方法 制作折射率与人体组织相当的仿组织超声模块,将其插入声通路中取代一部分水的声程,测量此时的校正系数并与水中所测得的数据进行比较.利用DBEC法对仿组织模块插入前后蓖麻油的USAC进行测量并比较结果.结果 探头通频带内,校正系数误差和蓖麻油USAC的测试误差均在7%以内,但校正系数误差与仿组织模块厚度的关系很复杂.结论 实验结果提示应在仿组织材料中预先测试探头的校正系数,以避免体内测量时DBEC法产生误差.     

不同厚度CT图像重建的DRR对射波刀治疗头部肿瘤精度的影响

采用1、2、3、4、5 mm共5种不同厚度的头部CT图像,将1 mm CT设计的计划作为基础,把基础计划中勾画的结构及靶区复制到其它4种不同的CT上生成相同剂量线分布的治疗计划。然后利用不同厚度CT图像生成的数字重建图像(DRR)进行六维(6D)引导定位治疗照射胶片,分析照射后胶片,得到1、2、3、4、5 mm层厚CT生成的DRR来定位6D追踪治疗头部病灶时产生的总误差是随着CT层厚的增加而增加。在1~4 mm层厚CT生成的DRR定位6D追踪治疗头部病灶产生的总误差随CT层厚的增加而变化较小,5 mm层厚CT生成的DRR定位6D追踪治疗头部病灶产生的误差较大,远大于系统要求误差。     

放射免疫分析中的数据处理方法

放射免疫分析灵敏度高、特异性强、精确度佳。但是一切实验都不可避免地会产生误差。为了提高测量精确度,要求我们竭力削弱各种误差的影响,获取最佳测量条件,并运用误差理论的有关原则来处理数据,以确定被测值或揭示被测对象对输入量的相应规律。 放射免疫分析最终目的是给出待测物质的准确量。数据处理就是将实验测得的未知样品的直接结果换算成剂量,通过误差分析和加工整理,计算其精度。多数放免分析系统基本上是均一性的,而且反应是在达到充分平衡后才用分离剂进行分离,因此剂量反应关系有典型的特点,可以通过实验数据作出一条尽可能反映真实函数关系的曲线,并对曲线作定量分析。 一、标准曲线的拟合:从一组离散的测量数据中,运用有关误差理论知识,求得一条能最佳地描述该原函数的曲线的过程即为拟合过程。数据拟合主要解决从给出的离散数据中找出变量之间的关系。     

ROC曲线评估FET移植前内膜厚度对妊娠结局的预测价值及临床分析

目的探讨移植前内膜厚度对冻融胚胎移植(FET)妊娠结局的预测价值。方法回顾性分析1261个FET周期的临床资料,利用ROC曲线分析移植前内膜厚度与妊娠结局的关系,计算内膜厚度的界值并进行分组,对各组的一般情况、临床资料及妊娠结局进行分析。结果根据ROC曲线计算其约登指数,得到内膜厚度的界值为9mm,根据这一内膜厚度将患者分为A组(≤9mm)和B组(9mm),比较两组的一般情况,移植胚胎数、不孕因素、用药方案及临床妊娠率,年龄及临床妊娠率的差异有统计学意义(P0.05)。进一步排除年龄因素的影响,在以内膜厚度分组的基础上按照年龄35岁分组比较妊娠率,在≤35岁组随着内膜厚度的增加妊娠率明显升高(P0.05)。结论 FET周期中,移植前内膜厚度对妊娠结局有一定的预测价值,尤其对于≤35岁患者,尽可能的增加内膜厚度是提高临床妊娠率的有效方式。     

基于高斯过程回归高强度聚焦超声仪器采集图像的层间测距算法

提出基于高斯过程回归的层间测距算法,通过对已知样本的训练,求解模型的参数,得到回归器,用于层间测距。通过对各实体组织进行超声扫描,得到相应的序列图像。运用到由高强度聚焦超声(high intensity focused ultrasound,HIFU)仪器采集的3组超声图像样本集中进行实验,验证方法的有效性和稳定性。测量绝对误差均值相对较小,在1～3 mm的范围内。绝对误差均值都低于0. 5 mm,而且相对误差的均值保持在10%以内,标准差比较稳定,浮动不大。而在4 mm和5 mm处测量误差相对较大,绝对误差均值在1mm左右,相对误差也会出现变大的趋势。但总体的相对误差在25%内。本研究提出的基于高斯过程回归的方法在1～3 mm的范围内,具有良好的测距结果,当距离超过3 mm时,测距误差相对较大。     

手舟骨的测量及临床意义

目的为研制手舟骨骨折的内固定器械及临床手术方式提供解剖学依据.方法48块成人干燥手舟骨及36块成人手舟骨湿骨标本,仔细观察其形态及主要血管压迹,游标卡尺对舟骨各部位进行测量.结果干燥骨组及湿骨组测量数据分别为舟骨结节高度(11.28±0.94)、(10.35±1.54)mm;舟骨腰部的厚度(12.02±1.90)、(11.21±1.20)mm,宽度(10.59±1.11)、(11.34±1.47)mm;舟骨体部最小厚度(6.51±1.22)、(8.54±1.07)mm;舟骨的纵轴长度(25.68±2.21)、(26.50±2.56)mm;舟骨嵴的宽度远端(6.50±1.06)、(6.64±1.18)mm,腰部(5.14±1.01)、(6.01±0.75)mm,近端为(4.42±1.16)、(5.71±0.78)mm.手舟骨的主要血管来自桡背侧部,由体部沿嵴部贯穿整个纵轴.结论依据手舟骨测量的数据及解剖特点,设计手舟骨骨折的新型内固定器械,避免内固定器破坏舟骨关节面及发生关节撞击综合征,尽量减少对舟骨血供的影响.     

国人足背动脉的解剖学测量及临床意义

目的:研究国人足背动脉的直径和管壁厚度,为足背动脉置管提供解剖学依据。方法:用体视显微镜分组测量31具尸体60侧足背动脉近端、中点和远端的内、外径。结果:足背动脉中点的外径、内径和管壁厚度分别为(2.47±0.49)mm、(1.28±0.50)mm和(0.60±0.16)mm,与近端和远端比较,3组均数差异均有统计学意义。3处足背动脉的内、外径及管壁厚度无侧别差异;男性管壁厚度大于女性;50岁以上者的外径和管壁厚度大于中、青年组。结论:本研究提供了华南地区国人足背动脉的解剖学相关资料,其结果对足背动脉穿刺置管术的开展与应用等具有参考价值。     

透析液pH值和电导率测量仪的设计与试验**

背景：在血液透析过程中,透析液的浓度直接决定了透析的效果。 目的：旨在设计一种应用于测量透析液浓度的pH值和电导率的装置,并通过试验对测量仪的性能进行测试和分析。 方法：开发用于测量透析液的pH值和电导率测量仪,提出一种频率可调的双极性间歇脉冲激励方法应用于电导率测量,极大地减少极化效应和电容效应对测量的影响,同时对电导率测量值进行温度校正。采用两点校正法对pH值进行标定,提高测量的精确度。 结果与结论：测量仪样机在实际的透析液中进行相关试验。测量仪的pH值测量值和标准值的相对误差小于1%,电导率的测量值与标准值的相对误差小于0.5%。通过对比试验说明,可调频率的间歇双极性脉冲法比双极性脉冲法的误差小,能及时地跟踪透析液浓度的变化。结果表明,测量仪能够实现对透析液浓度的精确测量,满足血液透析机对透析液的实时检测要求,可以广泛应用于血液透析机中透析液的浓度检测中。     

快速血液粘度测量过程中的误差分析

基于传统血液粘度测量方法的不足，本文提出了一种新的实时在体测量方法，并建立了数学模型。在此基础上，设计了相应的测量装置，进行了动物和病人血样的离体和在体实验。仪器经标准液标定结果表明，系统的总误差在3‰以内，在固定的切变率上，粘度测量值的误差均在3%以下。实验证明这种方法具有良好的一致性和重复性，本文就影响实验结果的主要误差来源及控制的方法进行探讨，旨在通过实验和理论分析得到系统的总的误差范围，以利于该测量方案的推广应用。     

A Mathematical Simulation to Assess Variability in Lung Nodule Size Measurement Associated With Nodule-Slice Position

The purpose of this study is to assess the variance and error in nodule diameter measurement associated with variations in nodule-slice position in cross-sectional imaging. A computer program utilizing a standard geometric model was used to simulate theoretical slices through a perfectly spherical nodule of known size, position, and density within a background of “lung” of known fixed density. Assuming a threshold density, partial volume effect of a voxel was simulated using published slice and pixel sensitivity profiles. At a given slice thickness and nodule size, 100 scans were simulated differing only in scan start position, then repeated for multiple node sizes at three simulated slice thicknesses. Diameter was measured using a standard, automated algorithm. The frequency of measured diameters was tabulated; average errors and standard deviations (SD) were calculated. For a representative 5-mm nodule, average measurement error ranged from +10 to −23 % and SD ranged from 0.07 to 0.99 mm at slice thicknesses of 0.75 to 5 mm, respectively. At fixed slice thickness, average error and SD decreased from peak values as nodule size increased. At fixed nodule size, SD increased as slice thickness increased. Average error exhibited dependence on both slice thickness and threshold. Variance and error in nodule diameter measurement associated with nodule-slice position exists due to geometrical limitations. This can lead to false interpretations of nodule growth or stability that could affect clinical management. The variance is most pronounced at higher slice thicknesses and for small nodule sizes. Measurement error is slice thickness and threshold dependent.     

植入式实验动物血糖动态监测装置的设计

目的 设计、研制一种用于实验动物的全植入式血糖浓度检测系统,通过一次植入手术可获得实验动物自然状态下经无线方式传输的动态血糖监测数据.方法 监测系统包括植入体和体外接收端两部分.植入体尺寸设计为11.5 mm×16.0 mm×5.0 mm,不超过实验大鼠体积的1/10.以SOF-SENSOR植入式葡萄糖传感器及其外围三电极伏安测量电路为核心,采用锂电池和稳压芯片构建供电,测量数据通过CC2540低功耗蓝牙系统芯片无线传输至体外.植入体外层包裹医用硅胶材料,以保护电路和提高植入体生物相容性.结果 体外验证实验表明,本系统可在2～34 mmol/L范围较准确地测量葡萄糖浓度(r=0.996 7),平均标准误差为0.193 mmol/L,灵敏度为9.24 nM(mmol/L),能够满足设计要求.结论 植入式实验动物血糖动态监测装置体积小,适合植入.体外血糖测量验证实验表明本装置的血糖测量范围、准确性、灵敏度及标准误差等均能满足设计要求.此装置有望为糖尿病病理和药效学研究提供重要的技术支持.     

Using cone-beam CT projection images to estimate the average and complete trajectory of a fiducial marker moving with respiration

Stereotactic body radiotherapy of lung cancer often makes use of a static cone-beam CT (CBCT) image to localize a tumor that moves during the respiratory cycle. In this work, we developed an algorithm to estimate the average and complete trajectory of an implanted fiducial marker from the raw CBCT projection data. After labeling the CBCT projection images based on the breathing phase of the fiducial marker, the average trajectory was determined by backprojecting the fiducial position from images of similar phase. To approximate the complete trajectory, a 3D fiducial position is estimated from its position in each CBCT project image as the point on the source-image ray closest to the average position at the same phase. The algorithm was tested with computer simulations as well as phantom experiments using a gold seed implanted in a programmable phantom capable of variable motion. Simulation testing was done on 120 realistic breathing patterns, half of which contained hysteresis. The average trajectory was reconstructed with an average root mean square (rms) error of less than 0.1 mm in all three directions, and a maximum error of 0.5 mm. The complete trajectory reconstruction had a mean rms error of less than 0.2 mm, with a maximum error of 4.07 mm. The phantom study was conducted using five different respiratory patterns with the amplitudes of 1.3 and 2.6 cm programmed into the motion phantom. These complete trajectories were reconstructed with an average rms error of 0.4 mm. There is motion information present in the raw CBCT dataset that can be exploited with the use of an implanted fiducial marker to sub-millimeter accuracy. This algorithm could ultimately supply the internal motion of a lung tumor at the treatment unit from the same dataset currently used for patient setup.     

血管形态研究中的计算机处理

传统对血管形态多用游标卡尺或间接摄片测量来描述,其操作复杂、速度慢及技术误差。计算机图象分析系统使形态学研究前进了一大步,但该系统复杂、昂贵,目前广泛使用尚有困难,我们对68例(男48、女20)腹主动脉杈位置不变的局解尸体标定拍照及对7例带有粥样斑块的左、右髂总动脉作1mm厚连续切片,数据由计算机及数字化仪处理,结果与实测相似,腹主动脉杈下端外径男性>女性。分权角女性>男性,玉块在横切面上分布以分杈管内侧部分明显且与新月型分布相似,并可定量,我们认为这方法可信、省时,可避免人为误差。     

Polymer microfiber mechanical properties: a system for assessment and investigation of the link with fibrous capsule formation

A novel microtensile testing instrument was developed to assess the mechanical properties of small-diameter polyethylene, polyurethane, and polyester microfibers. The instrument had a root-mean-square error of 2.96 microN for force measurement and 1.91 microm for displacement measurement. Microfibers ranging in diameter from 1.0 to 10.9 microm were strained at 2 mm/s in the device, and the slopes of their stress-strain curves (material moduli) were determined. Correlations between material modulus and previously published data on fibrous capsule presence and thickness for implanted polyethylene, polyurethane, and polyester microfibers were investigated. Results for the 1.0-5.9-microm microfiber diameter range showed that neither the percentage of unencapsulated fibers nor the capsule thickness correlated well with modulus. Correlation coefficients were 0.04 and 0.09, respectively. However, for the 6.0-10.9 microm diameter range the correlations were strong, 1.00 for both percentage of unencapsulated fibers and capsule thickness. It is suggested that the results reflect the greater attachment and mechanical interaction of cells with microfibers for the 6.0-10.9 microm-diameter range than for the 1.0-5.9 microm-diameter range.     

一种研究膜片材料细菌透过性的测试装置

本文介绍了一种细菌透过性的测试装置。该装置要由ＡＢ两池组成，池面积为７ｃｍ＾２。本实验研究了４种膜性材料的透菌情况，结果表明培养４小时两种实验菌均未透过，此后因试材孔径的大小而细菌透过量明显不同。我们的实验提示该装置简单，适用于膜性材料细菌透过性的测量。     

Optimization of the arthroscopic indentation instrument for the measurement of thin cartilage stiffness.

Structural alterations associated with early, mostly reversible, degeneration of articular cartilage induce tissue softening, generally preceding fibrillation and, thus, visible changes of the cartilage surface. We have already developed an indentation instrument for measuring arthroscopic stiffness of cartilage with typical thickness >2 mm. The aim of this study was to extend the applicability of the instrument for the measurement of thin (<2 mm) cartilage stiffness. Variations in cartilage thickness, which will not be known during arthroscopy, can nonetheless affect the indentation measurement, and therefore optimization of the indenter dimensions is necessary. First, we used theoretical and finite element models to compare plane-ended and spherical-ended indenters and, then, altered the dimensions to determine the optimal indenter for thin cartilage measurements. Finally, we experimentally validated the optimized indenter using bovine humeral head cartilage. Reference unconfined compression measurements were carried out with a material testing device. The spherical-ended indenter was more insensitive to the alterations in cartilage thickness (20% versus 39% in the thickness range 1.5-5 mm) than the plane-ended indenter. For thin cartilage, the optimal dimensions for the spherical-ended indenter were 0.5 mm for diameter and 0.1 mm for height. The experimental stiffness measurements with this indenter correlated well with the reference measurements (r = 0.811, n = 31, p < 0.0001) in the cartilage thickness range 0.7-1.8 mm. We conclude that the optimized indenter is reliable and well suited for the measurement of thin cartilage stiffness.     

Information processing by parafoveal cells in the primate nucleus of the optic tract

We recorded from single units in the pretectal nucleus of the optic tract (NOT) of the nonhuman primate. Specifically, we examined units that are modulated during smooth tracking of a small laser spot against a dark background. We used a nonlinear optimization procedure to determine whether the unit responses of these parafoveal cells are better described by a model that incorporates retinal error motion parameters or by a model that incorporates eye motion parameters. Our main finding was that all the cells in our sample group were better fit with a three-component model that incorporated retinal error motion parameters of position, velocity and acceleration (average coefficient of determination = 0.84) than a model that used position, velocity and acceleration components of eye motion (average coefficient of determination = 0.68). Other analyses involved comparison of goodness of fit between the three-component retinal error model and two-component retinal error models that excluded position or acceleration related terms. We found that there was a statistically significant degradation in the fit when position and acceleration related terms were dropped from the retinal error based model (P<0.05). Unit data from experiments in which the laser spot was extinguished for a brief period of time during tracking showed that the unit response was decreased following the target blink. We conclude on the basis of this and previous experimental data and our dynamic modeling approach that the parafoveal cells in the NOT primarily encode retinal error motion. Further they encode position, velocity and acceleration components of retinal error that could be used by other downstream structures for synthesis of a smooth-pursuit eye movement. Electronic Publication