The Methodology of Probe Design with Better Resolution and Less Resistive Donut Probe to Achieve the Best Performance

Probes are the interface between microsystems and bio-cells.The ideal interface is one-to-one interface.Though variousresearch groups have been able to establish some sort of interfaces after many years of research,they are very crude.Neurons aremillions in numbers,whereas the prostheses successfully built so far have only a few hundred probes at best.Creating an ef-fective interface is still far away.Though we have micro-and nano-technologies,we couldn’t build a prosthesis with an effectiveresolution.Main reasons behind it are the type of probe being used and the poor design of the probe.To address this problem,wedeveloped a methodology to design a probe and an array of probes with better resolution and less resistive donut probe.Thismethodology helps us to design a probe optimizing all the parameters.We presented our methodology through a design that iscapable of 70 μm penetration inside the tissue.The tissue heating by our designed probe is only 0.411 °C.We also characterizedthe donut probe,which could be used by any research group to design a donut probe of their specific need.     

Patient-Specific Design and Biomechanical Evaluation of a Novel Bipolar Femoral Hemi-Knee Prosthesis

While total knee replacement is successful, hemiarthroplasty is necessary for some young, obese and active patients who are especially not suitable for unicompartmental or total knee prostheses. Hemiarthroplasty also provides an opportunity for children with bone tumors. The design ofhemiarthroplasty should be patient-specific to reduce contact stress and friction as well as instability, compared to conventional hemi-knee prosthesis. A novel bipolar hemi-knee prosthesis with two flexion stages was developed according to a healthy male＇s knee morphological profile. The motion mode of the bipolar hemi-knee prosthesis was observed through roentgenoscopy in vitro experiment. The biomechanical properties in one gait cycle were evaluated though finite element simulation. The bipolar hemi-knee prosthesis was found to produce knee flexion at two stages through X-ray images. The first stage is the motion from upright posture to a specified 60~ flexion, followed by the second stage of motion subsequently to deep flexion. The finite element simulation results also show that the designed hemi-knee prosthesis has the ability to reduce stresses on the joint contact surfaces. Therefore, it is possible for the bipolar hemi-knee prosthesis to provide better biotribological performances because it can reduce stresses and potentially wear on the opposing contacting surface during a gait cycle, orovidin~ a t~romisin~ treatment strate~v in future Joint renair znd renlneement     

髋关节置换治疗高龄不稳定型股骨粗隆间骨折的临床效果观察

目的:探讨髋关节置换手术治疗高龄人群不稳定型股骨粗隆间骨折的稳定性及愈后生活质量。方法:选取我院骨科收治的110例不稳定型股骨粗隆间骨折患者作为研究对象,随机分为两组,观察组55例采用人工全髋关节置换术,对照组55例采用DHS内固定治疗,观察两组患者的手术时间、手术出血量、平均住院时间、临床疗效、术后并发症及愈后生存质量。结果:观察组手术时间及手术出血量大于对照组,但患者平均卧床时间及显著短于对照组(P0.05)。观察组手术总有效率为87.27%,对照组手术总有效率为70.90%,观察组手术效果明显优于对照组(P0.05)。观察组术后并发症发生率为7.27%,显著低于对照组(25.45%)(P0.05)。观察组患者生活质量满意度为80.00%,明显高于对照组(61.82%)(P0.05)。结论:髋关节置换手术能减少术中出血量、患者下地活动时间早,局部组织修复速度快,对于体质较差、年龄大的老年患者,该术式是延长预期寿命的最佳手术方式。     

Effects of sitting postures on risks for deep tissue injury in the residuum of a transtibial prosthetic-user: a biomechanical case study

Transtibial amputation prosthetic-users are at risk of developing deep tissue injury (DTI) while donning their prosthesis for prolonged periods; however, no study addresses the mechanical loading of the residuum during sitting with a prosthesis. We combined MRI-based 3D finite element modelling of a residuum with an injury threshold and a muscle damage law to study risks for DTI in one sitting subject in two postures: 30°-knee-flexion vs. 90°-knee-flexion. We recorded skin-socket pressures, used as model boundary conditions. During the 90°-knee-flexion simulations, major internal muscle injuries were predicted (>1000 mm³). In contrast, the 30°-knee-flexion simulations only produced minor injury ( < 14 mm³). Predicted injury rates at 90°-knee-flexion were over one order of magnitude higher than those at 30°-knee-flexion. We concluded that in this particular subject, prolonged 90°-knee-flexion sitting theoretically endangers muscle viability in the residuum. By expanding the studies to large subject groups, this research approach can support development of guidelines for DTI prevention in prosthetic-users.     

Recovery of the first and second phases of the M wave after prolonged maximal voluntary contractions

IntroductionWe compared the recovery of muscle electrical properties after maximal voluntary contractions (MVCs) of 1 and 3 min duration by examining separately the first and second phases of the muscle compound action potential (M wave).MethodsM waves were evoked by supramaximal single shocks to the femoral nerve throughout the 30-min recovery following 1-min and 3-min MVCs. The amplitude, duration, and area of the M-wave first and second phases, along with peak-to-peak amplitude and total area, were measured from the knee extensors.Results(1) The amplitude of the M-wave first phase increased to the same extent (and had the same time course of recovery) after the 1 and 3-min MVCs, whereas the amplitude of the second phase increased more markedly after the 1-min than after the 3-min MVC (P < 0.05). (2) The first phase remained enlarged for 2 min after exercise, whereas the augmentation of the second phase only lasted for 30 s. (3) After 30 min of recovery, the amplitude, area, and duration of both the first and second phases were decreased compared to control values (P < 0.05).ConclusionsThe similar enlargement of the M-wave first phase after the 1 and 3-min MVCs suggests that the extracellular K⁺ concentration attained after these contractions was similar. The mechanisms responsible for the long-term decreases in M-wave amplitude and duration are unknown at present, but are likely due to a decrease in the amplitude of individual transmembrane potentials and an increase in conduction velocity.     

全髋关节置换术用于股骨颈骨折患者的临床疗效评价及对血清OPG、BGP、ALP、CRP、IL-6的影响

目的:分析全髋关节置换术用于股骨颈骨折患者的临床效果及对血清骨保护素(OPG)、骨钙素(BGP)、碱性磷酸酶(ALP)、C反应蛋白(CRP)、白细胞介素-6(IL-6)的影响。方法:选择我院2014年3月~2016年3月收治的102例股骨颈骨折患者,按抽签法分为对照组与研究组,每组各51例。对照组采用半髋关节置换术治疗,研究组采用全髋关节置换术治疗。比较两组的临床疗效,治疗前后Harris评分、血清OPG、BGP、ALP、CRP、IL-6水平的变化及术后并发症的发生情况。结果:治疗后,研究组的优良率显著高于对照组(P0.05);两组Harris评分、血清OPG、BGP、ALP、CRP、IL-6水平均较治疗前显著上升,且研究组Harris评分显著高于对照组(P0.05),而两组OPG、BGP、ALP、CRP、IL-6水平比较差异无统计学意义(P0.05)。结论:全髋关节置换术用于股骨颈骨折的临床效果肯定,虽可引起血清OPG、BGP、ALP、CRP、IL-6水平上升,但未增加手术风险。     

Development of leg chordotonal sensory organs in normal and heat shocked embryos of the cricket Teleogryllus commodus (Walker)

This paper describes the embryonic development of some parts of the sensory peripheral nervous system in the leg anlagen of the cricket Teleogryllus commodus in normal and heat shocked embryos. The first peripheral neurons appear at the 30% stage of embryogenesis. These tibial pioneer neurons grow on a stereotyped path to the central nervous system and form a nerve which is joined by the growth cones of axons that arise later, including those from the femoral chordotonal organ, subgenual organ and tympanal organ. The development of these organs is described with respect to the increase in number of sensory receptor cells and the shape and position of the organs. At the 100% stage of embryogenesis all three organs have completed their development in terms of the number of sense cells and have achieved an adult shape. To study the function of the tibial pioneer neurons during embryogenesis a heat shock was used to prevent their development. Absence of these neurons has no effect on the development of other neurons and organs proximal to them. However, the development of distal neurons and organs guided by them is impaired. The tibial pioneer neurons grow across the segmental boundary between femur and tibia early in development, and the path they form seems to be essential for establishing the correct connections of the distal sense organs with the central nervous system.     

Responses and locations of neurones in the locust metathoracic femoral chordotonal organ

Summary Insect legs possess chordotonal organs which monitor leg angle, and the direction, velocity and acceleration of leg movements. The locust metathoracic femoral chordotonal organ (mtFCO) has previously been studied morphologically and physiologically, but no detailed analysis of the responses of individual neurones, and their location in the organ has so far been produced. By recording from, and staining mtFCO neurones I have been able to compile for the first time such a map. The distribution of neurone somata in the locust mtFCO is more complex than previously thought: receptors sensitive to both stretch and relaxation of the apodeme are distributed throughout the organ. Seventeen response types were encountered. Neurones with a particular response type have somata in comparable locations within the mtFCO. Comparisons are made between the response types found in the stick insect and those in the locust. The possible functions of some of the responses are discussed.Abbreviation (mt)FCO (metathoracic) femoral chordotonal organ - F-T femur-tibia     

The formation of a neo-intima in textile prostheses implanted in the aorta of rats and dogs

Summary The formation of a neo-intima in textile prostheses implanted in the rat and dog aorta was studied by means of light- and scanning electron microscopy. Two independent cellular layers (the superficial and deep ingrowth layers) developed on the free surface and under the fibrin layer initially deposited on the inner surface of the prostheses. The superficial ingrowth layer invades the prosthesis from both the proximal and distal aortic stumps and extends over the primary fibrin layer, or replaces it. This layer consists mainly of smooth muscle cells of the triangular aortic type covered by endothelial-like cells. The deep ingrowth layer originates from cellular elements of the prosthetic bed. Fibroblasts, myofibroblasts and spindle-shaped smooth muscle cells invade the fibrin layer through the interstices of the fabric structure of the prosthesis. Precursors of endothelial cells, however, are absent from this population. The superficial and the deep ingrowth layers may become joined by progressive replacement of the fibrin layer, but remain distinguishable because of their different cellular components.When a continuous cellular layer is established on the inner surface of the prosthesis, and this is then covered by endothelial-like cells, the neo-intima formed remains stable during long-term studies.     

Influence of resin cement rigidity on the stress distribution of resin-bonded fixed partial dentures

The mechanical properties of the adhesive cement used in resin-bonded fixed partial dentures (RBFPD) can modify the clinical performance of the rehabilitation. The goal of this study was to evaluate the influence of the elastic modulus of different cements on the stress distribution in RBFPD using finite element analysis. For that an anterior 3-unit prosthesis was modeled based in a stereolithography file. The model was meshed with tetrahedral elements and materials considered isotropic, linearly elastic and homogeneous. The force applied to the palatal area of the lateral incisor (pontic) at 45° was 100?N. The cements used presented 7 different elastic modulus (E): 2, 6, 10, 14, 18, 22 or 26?GPa. The total deformation, von-Mises stress and maximum principal stress criteria were used to calculate the results. The lower tensile stress occurred in the cement layer with E?=?2?GPa [25.6 (canine) and 16.32?MPa (incisor)]. For the prosthesis, the model with the lower tensile stress [287 (canine) and 248?MPa (incisor)] occurred when the cement presented E?=?26?GPa.

In this way, the stress concentration may have its magnitude modified depending on the stiffness of the cement. Since more flexible cements concentrate less tensile stress in its structure, but allow an increased displacement of the prosthesis, which is friable and rigid and ends up concentrating more tensile stress at its connector. In that way the clinician should avoid the use of adhesive cement with lower elastic modulus due to it increases the stress concentration in the ceramic.