先天性上睑下垂发病机制与手术设计的研究

目的：探讨先天性上睑下垂的发病机制，为手术方法的设计提供依据。方法：对73例（103眼）先天性上睑下垂进行了上睑提肌肌力，肌电图，肌弹性的测量及解剖学，组织学方面的观察。结果：肌电图显示该肌收缩强度正常平均值为500uV/D，部分肌力较差的患者（18％）肌收缩强度达260－350uV/D接近正常平均值，少数骨力在3－5mm的患者（9．99％）肌收缩强度达到正常平均值。术中观察85％的患者上睑提肌弹性良好，肌伸民可达15－20mm。组织学观察发现17％的患者上睑提肌为正常组织，结论：先天性上睑下垂的发生原因除肌发育不良外，上睑提肌内，外角过度紧张也是其重要因素，并根据病因制定了合理有效的手术 方式。     

Characterization of the structure and properties of authentic and counterfeit polypropylene surgical meshes

A counterfeit version of the Ethicon Prolene polypropylene mesh was distributed to hospitals and clinics and unintentionally implanted into patients undergoing tension-free hernia repair. On December 19, 2003, the Food and Drug Administration (FDA) issued a public health web notification indicating that the counterfeit mesh was not sterile or safe to use. To develop safety recommendations for patients with the counterfeit mesh implant, we compared the counterfeit’s structural, physical, chemical and mechanical properties with polypropylene meshes previously cleared by FDA. The mesh fibers for all the products tested were found to have similar chemical and physical properties. The mechanical properties were directly related to the knitted structure (loop size, repeat distance, fabric tightness) and the porosity. Extracts from the counterfeit mesh passed cytotoxicity screening tests. The FDA further recommended that if the mesh had been inadvertently implanted, then those patients should be monitored as would be the practice for any patient with an implanted surgical mesh.     

The repeated compression of powders

Powders were subjected to repeated compression in a tablet press, the ejection mechanism of which had been disconnected. The force detected at the upper punch was found to change with successive compressions, the magnitude of the change being dependent on the powder, the compressive force and the interval between compressions. Repeated compression also caused a change in tablet crushing strength. With compression intervals of 1.2 s, all substances showed an significant increase in strength. With longer time intervals, the increase was reduced and in some cases, a diminution in strength occurred.     

个人收入与医疗服务需求及其弹性

通常情况下，当收入增长时，消费者对霜种商品需求的增加减少将做出必然的反映，两者之间增量的比即是消费者对这种商品的收需求弹性。分析医疗服务需求收入弹性，从总体上讲呈弱势，高收入组弹性大于低收入组弹性；医疗费用占收入的比重是一个增长的趋势，贫困和低收入人群医疗费用支出占收的比重高于高收入人群。     

Some parameters for testing deformation of elastomeric impression materials

Because of conflicting published data, the temperature rise in four elastomeric materials was measured with a thermistor during setting in the oral cavity and in metal and plastic moulds of varying shapes and volumes for 'elastic set' specimens. The clinical temperature rise was 2-3 degrees C higher in the molar region than anteriorly, except for the polysiloxane. The temperature range attained in the set materials varied from 29 degrees C to nearly 35 degrees C for clinical and in vitro specimens. The average time taken by a group of operators to remove this type of impression from the mouth was five seconds. In a custom tray with light and heavy viscosity materials, the syringe material layer was only 0-0.15 mm thick and, essentially, the heavy viscosity material provided the elastic components for the impression.     

ACL reconstruction by bone-patellar tendon-bone graft: mechanical evaluation of the elastic modulus and failure modes

The aim of this study was to apply an engineering approach to study the biomechanical behaviour of both native and reconstructed anterior cruciate ligaments (ACL) under tensile test, simulating the primary stability of the reconstructed ACL in the immediate postoperative period, when the bone callus has not formed yet. We used the bovine bone-patellar tendon-bone grafts to reconstruct ACL in bovine knees. The grafts were fixed by means of titanium interference screws and titanium transverse compressive screws. We tested 18 native and 18 reconstructed ligaments (7 with interference screws and 11 with transverse compressive screws). We applied mechanical tension at a 500 mm/min strain rate, and observed the mode of failure. The data analysis confirmed the different behaviour recorded in load elongation curves, a difference enhanced in stress-strain curves for both fixation methods. The stress-strain patterns for the interference screw and for the native ligament were quite similar.     

芳香族热致液晶聚（对羟基苯甲酸—对苯二甲酸双酚A酯）的流变性能

用Ｉｎｓｔｒｏｎ３２１１型毛细管流变仪研究了以对羟基苯甲酸（ＰＨＢ）、对苯二甲酸（ＴＰＡ）和双酚Ａ（ＢＰＡ）为单体合成的共聚芳酯液晶熔体的流变性能。结果表明，切变速率、熔体温度及ＰＨＢ链节含量对切粘度和结构粘度有很大的影响。切变速率在１０～１０３／Ｓ、温度２９５～３３０℃范围内，共聚酯粘流活化能△Ｅη为７４．５～２０５．１（ｋＪ／ｍｏｌ）。液晶熔体在剪切流中存在屈服应力τｏ，随温度升高τｏ值降低。在低温、低切变速率下，共聚酯熔体的弹性很小，甚至呈现挤出收缩现象。     

正常人颈总动脉、肱动脉、胫后动脉血流动力学参数分析

目的 通过运用超声检测方法采集正常人颈总动脉、肱动脉、胫后动脉的血流动力学参数进行分析,探讨监测人体多处动脉血流动力学变化的意义.方法 在30例正常人中,将超声多普勒探头置于受试者左侧颈总动脉起始段、左侧肱动脉、左侧胫后动脉测量以上动脉的血管内径、动脉血流流速波传导时间、血流加速度及收缩期射血面积,对获得的多处、多种血...     

通过流动腔实验测量HL-60细胞微绒毛弹性

目的滤除平行平板流动腔实验数据中的噪声,以清晰观测细胞滚动黏附过程,并发展基于流动腔实验的细胞微绒毛弹性的测定方法。方法运用小波分析方法技术,分离从流动腔实验中得到的E-选择素介导的HL-60细胞滚动黏附实验数据的高频热噪声信号;利用能量均分定理和拴缚细胞的力平衡方程,构建细胞微绒毛的伸长与弹性间的关系。结果通过小波分析滤噪,可以清晰定位细胞滚动黏附的不同阶段:自由滚动-减速-停止-加速;在壁面剪切应力为0.01～0.06Pa的条件下,源于热噪声的细胞脉动能量约占总的脉动能的80%,测得HL-60细胞微绒毛的弹簧常数为(13.7±7.4)μN/m。结论小波分析技术可滤除流动腔细胞滚动黏附实验数据中的热噪声;细胞热脉动信号中含有细胞微绒毛弹性的信息,使得人们可以采用流动腔实验技术来测量细胞微绒毛的弹性。     

瞬时波强技术对糖调节受损者胫前动脉弹性变化分析

目的 探讨瞬时波强（WI）技术对糖调节受损患者胫前动脉的弹性变化及意义.方法 根据空腹血糖值及口服葡萄糖耐量试验血糖值把研究对象分为3组：A组（血糖正常组）,B组（新增空腹血糖受损组）,C组（糖尿病前期组）,分别测定各组下肢胫前动脉WI的以下指标：血管压力应变弹性系数（Eρ）、僵硬度（β）、增大系数（AI）、顺应性（AC）、脉搏波传导速度（PWVβ）、负向面积（NA）.结果 与A组对比,C组的β、Eρ 、PWVβ差异有统计学意义（P＜0.05）;B组的β、Eρ、AI、PWVβ、NA和C组的AI、NA有增加趋势,但差异无统计学意义（P＞0.05）;B、C组的AC差异无统计学意义（P＞0.05）.结论 糖尿病前期胫前动脉已出现弹性减低,WI技术对糖调节受损下肢动脉病变的早期预测具有重要价值.