载荷强度对受载胫骨中骨陷窝-骨小管系统内溶质输运速率影响

目的 利用有限元法研究载荷强度对受载胫骨中骨陷窝-骨小管系统（lacunar-canalicular system,LCS）内溶质输运速率的影响。方法 基于成年鼠胫骨的micro-CT扫描图像,利用Mimics、Hypermesh、FEBio等软件建立其胫骨有限元模型,且视为均质的两相-溶质材料。通过设置3组不同扩散率（3、15、30 μm2/s）的溶质和载荷强度（0.2、2.0、5.0 N）,得到输运速率和溶质扩散率以及载荷强度之间的关系。对比光脱色荧光恢复（fluorescence recovery after photobleaching, FRAP）实验数据与有限元法得到的结果,分析载荷刺激对输运增强率的影响。结果 输运速率均随着扩散率和载荷强度的增大而增大。通过与FRAP实验的数据进行比对发现,有限元法得到的结果基本符合溶质运移规律。结论 研究结果可为研究皮质骨深层区域的力响应以及流动性提供一定基础,也为进一步揭示骨再生机制提供借鉴。     

In vivo forces on oral implants supporting a mandibular overdenture: the influence of attachment system

This study was designed to gain insight into the influence of the attachment system on the loading conditions of oral implants supporting a mandibular overdenture on two implants. Five patients were selected and were provided with two implants in the canine area of the mandible (Brånemark System). All patients received a new mandibular overdenture that could be mounted on an ovoid-shaped bar (Dolder, C&;M): (a) with and (b) without bilateral extensions and (c) on ball-attachments (Nobel Biocare). Using three strain gauges attached to the outer surface of the 5.5-mm standard abutments, the axial forces and bending moments on both supporting implants could be quantified. Load registrations were made during application of 50 N on seven predetermined positions along the occlusal surface of the prosthesis and during maximal biting in maximal occlusion (clenching). The results revealed no differences in induced axial force for the various anchorage devices, unlike the differences in bending moment. Although there is a tendency for better axial load sharing with bars and better sharing of bending moments with ball attachments, these differences were not significant.     

Sustained Virological Response in Chronic Hepatitis C Patients after a 6- and a 36-Month Interferon-a2b Treatment Schedule. A Multicenter,Randomized, Controlled Study

With the introduction of medical treatment (chenodeoxycholic acid therapy) of cholesterol gallstones, the prediction of the gallstone type, cholesterol — non-cholesterol stones (i.e. cholesterol predominating or not), has become important. In 24 consecutive patients admitted for surgery because of gallstones, the value of various criteria for differentiation between the two types of stones was assessed. It is concluded that the combined requirements of radiolucency of the stones and a cholesterol saturation index in duodenal bile above 1.00 constitutes a fairly reliable method for selection of patients for dissolution therapy with chenodeoxycholic acid.     

中重度妊高症硫酸镁负荷治疗分析

目的 中重度妊高症如何使硫酸镁效果最大化.方法 58例中重度妊高症分成等数的观察与对照两组.降压、利尿、镇静治疗相同.观察组先给负荷剂量硫酸镁,再静脉维持,必要时晚间肌注.对照组不给负荷剂量.对比2组血压、并发在,分娩方式、羊水性质、Apgar评分等.结果治疗后血压下降,观察组优于对照组,且具统计学意义(P>0.05)...     

1.5 mile run time and body mass predict 8 mile loaded march performance,irrespective of sex

Objectives

To develop a statistical model to predict 8 mile Loaded March (LM) performance and quantify differences in physical characteristics for men and women British Army Personnel.

单个种植牙的种植体边缘骨的应力分析

目的 :研究负荷对单个种植牙的种植体边缘骨的应力影响。方法 :采用电阻应变片法 ,测试在垂直负荷和2 0°远中向的角度负荷时种植体边缘骨的应力。结果 :应力与负荷大小、悬臂长度成正比。应力主要集中在种植体的颈部和远中根尖部 ,角度负荷更易造成种植体的边缘骨的应力集中。结论 :实验结果提示 :通过减小咬合力 ,降低牙尖高度 ,避免使用游离端种植义齿 ,可以减小种植体颈部和远中面的根尖部的应力。     

装卸工人负荷量与心率关系现场试验

本文报道12名装卸工人负重心率关系的现场试验结果,应用方差及回归分析方法对比七个因素和二项指标进行了统计分析。通过多因素分析,找出了主要影响因素。试验结果表明,今后制定全国标准时除应考虑性别、负重量外,还应考虑负重方式、道路坡度以及生理参数(体表面积等)等因素。     

A compliant interface for total knee arthroplasty

Low pressure sensitive Fujifilm was used to measure the load distribution between the resected tibial surface and a tibial component at axial loads up to 3,000 N for a rigid interface, a compliant interface of dacron double-sided velour, and a cemented interface. The pressure patterns consisted of a multitude of small red dots, generally reflecting the slight irregularities of the cut surface and the stiffness of the cancellous bone at the surface. The pressure patterns were photographed with high-contrast film and input into a computer using a photodiode matrix camera. The data were analyzed to yield the number of contact points for each sample. The velour was more effective in distribution of load to the proximal tibia than the rigid and cemented interfaces, while there was no significant difference between the cemented interface and the rigid interface. A second series of tests showed significant increases in contact points from rigid to one layer to two layers of velour. Cyclic axial loading tests were performed to study the characteristics of rigid and compliant interfaces in a model of in vitro subsidence. Static pressure patterns taken at regular intervals showed that subsidence occurred in vitro in up to 1/3 of the tibias, and that the regions of load transfer could change with time. A model of subsidence was proposed and it was suggested that a velour layer could inhibit the subsidence.     

Injury risk-workload associations in NCAA American college football

Objectives

To determine injury risk-workload associations in collegiate American Football.

Load shift of the intervertebral disc after a vertebroplasty: a finite-element study

Infiltrating osteoporotic cancellous bone with bone cement (vertebroplasty) is a novel surgical procedure to stabilize and prevent osteoporotic vertebral fractures. Short-term clinical and biomechanical results are encouraging; however, so far no reports on long-term results have been published. Our clinical observations suggest that vertebroplasty may induce subsequent fractures in the vertebrae adjacent to the ones augmented. At this point, there is only a limited understanding of what causes these fractures. We have previously hypothesized that adjacent fractures may result from a shift in stiffness and load following rigid augmentation. The purpose of this study is to determine the load shift in a lumbar motion segment following vertebroplasty. A finite-element (FE) model of a lumbar motion segment (L4-L5) was used to quantify and compare the pre- and post-augmentation stiffness and loading (load shift) of the intervertebral (IV) disc adjacent to the augmented vertebra in response to quasi-static compression. The results showed that the rigid cement augmentation underneath the endplates acted as an upright pillar that severely reduced the inward bulge of the endplates of the augmented vertebra. The bulge of the augmented endplate was reduced to 7% of its value before the augmentation, resulting in a stiffening of the IV joint by approximately 17%, and of the whole motion segment by approximately 11%. The IV pressure accordingly increased by approximately 19%, and the inward bulge of the endplate adjacent to the one augmented (L4 inferior) increased considerably, by approximately 17%. This increase of up to 17% in the inward bulge of the endplate adjacent to the one augmented may be the cause of the adjacent fractures.