Abstract:bjective Investigate the hemodynamical mechanism that rolling manipulation can promote blood circulation. Methods Hemodynamics in an artery with a moving stenosis forced by rolling manipulation has been investigated. By solving linearized N - S equations, varies of factors contributing to the flow rate have been discussed, including different Horizontal Penetration Parameters, different Maximal Stenosis Degrees and different Manipulation Frequencies. Results Larger Horizontal Penetration Parameter, faster Manipulation Frequency and smaller Maximal Stenosis Degree will make the flow increase. Conclusion The promition of the arterial blood flow rate by rolling manipulation depends on seceral factors, it agrees with the fact that appropriate rolling manipulation can promote blood circulation.

Abstract:Objective To compare some lumped - parameter models often used in simulating input impedance in systemic circulation, and apply the results to heart failure and hypertension. Methods Some methods and criterions, which can ensure the precision in simulation, were introduced to obtain the model parameters with the least square method. Results The precision of Bruttini&Gnudi four - element model and Liu ZR modified five - element model in simulation were better than other models. Physiological facts in heart failure and hypertension were well reflected by these two models. Conclusion Four - element model and modified five - element model are relatively applicable lumped - parameter models.

Abstract:Objective To evaluate the biomechanical properties of self- designed anterior cervical bioglass- coating plate system (ACBPS) . Methods A 0.3mm coating thickness of bioglass was sprayed isoionically onto the surface of the screws and the reverse side of the plate. 18 cervical spine specimens(C2 -T1)were divided into three groups. After decompression, bone graft and implant fixiation with ACBPS, ACPS or Orion, the load-displacement, torque, twisting stiffness and ultimate mechanical performance were tested and compared. Furthermore, ACBPS and ACPS were subjected to pull-out test and fatigue test, and the results were further justified with a three dimensional finite element model. Results The results showed that the ranges of displacement decrease of ACBPS group was more significant than those of ACPS or Orion ( P < 0.05 ) in flexion-extension and the longitudinal displacements after fixation were lower ( P < 0.05 ) than those two implant groups as well. But torque,twisting stiffness and ultimate mechanical performance of ACBPS group were similar to those of ACPS or Orion ( P > 0.05 ) group. The maximum pull-out force and its relative displacement and energy absorption of ACBPS were greater than those of ACPS or Orion ( P < 0.05 ) . Its fatigue strength was 586.86MPa and could bear 6.55 · 105 times of loading on average before they appeared fissures externally to the screw holes. Althougth the stress concentration was located circum-ferentially of the holes of ACBPS, the diameter of holes and the distance of edges were still in the margin of safety. Conclusion ACBPS can not only provide sufficient biomechanical stability and prevent the loosening of screws or the system, but also reduce the stress concentration on the holes of the plate by its bioglass coating which prolongs its service life and is safe for long - time internal fixation.

Abstract:Objective To observe the mechanism of traumatic brain injury (TBI) following fluid percussion in rats. Methods TBI was made by the fluid percussion device. The intracellular free calcium concentrations([Ca2+ ] i) of hippocampus in the TBI was detected by flouormeter with fluorchrome Fura - 2/ AM. Results [Ca2+ ]i was increased markedly with moderate TBI. Conclusion The calcium channel of cell membrane was open after TBI which could cause a large mount of calcium into cell inner, and increased concentration of intracellular free calcium. It might play an important role in the experimental brain injury.

Abstract:Objective To investigate the cause and process of crack generation and propagation in fretting wear of bone and to study the fretting wear mechanism between prostheses and bones. Methods Conducting a fretting wear experiment system with a dried thigh bone and titanium alloy. Results Bone structures in fretting areas become loose and obvious cracks could be found in both longitudinal and cross -sectional planes of the bone. Conclusion Bone structures in fretting wear will induce fatigue failure and this will further cause loosening of prostheses.

Abstract:Objective To study the compression properties of normal articular cartilage. Methods 40 cylinder specimens were divided into A B C D groups randomly. Group A and B were used to measure stresses and strains of articular cartilage after one - minute compression by using two different micro - mechanical setups. Group C was used to measure changes of strains with time under static loading. Group D was used to measure changes of stresses with time under static strain compression. Results CD The instantaneous stress - strain curves were nonlinear and the difference between the elastic moduli of the two setups was statistically significant. (2) When articular cartilage compressed under static loading, strain increased with time and attained its maximum eventually. ￤hen articular cartilage compressed under static strain, stress decreased with time and attained equilibrium eventually. Conclusion Articular cartilage is a good viscoelastic material and has great elasticity and instantaneous anti- compression property. The instantaneous moduli measured with the above two setups are different.

Abstract:Objective The viscoelastic property of the cancellous bones of the femoral head of the fresh cadaver were studied. Methods the tensile stress relaxation experiment and creep experiment were done in three directions: Longitudinal N transverse and 45 degrees. Results The data of the tensile stress relaxation and creep of three directions were reported. The reduced stress relaxation and creep functions, the curves and the irregular functions and curves of the relations between the stress relaxation and creep' s quantities and angles were also reported. Conclusion The quantities of stress relaxation and creep of the cancellous bones of the femoral head in the longitudinal direction are greater than those in the other two directions and the cancellous bone of the femoral head is an anistropic material.

Abstract:Objective The foot motion angles in 3D space were measured in this study. Methods Thermoplastic material were molded as the bracket of 3D marker triad, which can closely follow the contours of foot. This study used ALBA VISION ACAM50 3D motion analysis system to detect the marker position and calculate the foot motion angles in 3D space. Results The 3D foot motion pattern were properly described. Conclusion This method can be applied for research and clinical study of 3D foot motion.

Abstract:Objective To study the flow property in microcirculation and material exchange. Methods Based on the porosity concept used in the petroleum fields, this paper set up the double porosity medium model of capillary and tissue. In the case of regardless the liquid permeable pressure of capillary and tissue , the leakage formula is obtained. The numercal analysis was conducted under different conditions; with the affection of time and without the affection of time. Results The comparison of numerical results show that: the leakage volume decreased along capillary without the affection of time; with the affection of time the leakage volume increased quickly at first and the decreased slowly. Conclusion The results are benefits to further study of material and energy exchange in the system of capillary and tissue.

Abstract:Objective To evaluate the biomechanical effects of low calcium diet on male and female rat femur and compare the biomechanical difference between male and female rat. Methods Sixty 3 -month - old Sprague - Dawley male and female rats were randomized into three groups: control group , very low calcium diet group (VLCD) and low calcium diet group (LCD) . After 90 days, all rats were killed. The left femur from each rat was obtained for three - point bending test. Results Comparing with control group, VLCD and LCD group had no significant difference in biomechanical properties in female rats. Biomechanical properties in male rats also had no significant differences between LCD and control group, but male rats of VLCD had significantly lower maximum load, energy absorption and stiffness than those of control group. Conclusion The results indicated biomechanical properties in male rats were reduced more than those in female rats with the effect of low calcium diet, which body weight may play an important role.

Abstract:Objective To study the biomechanical reasons of internal fixation failure. Methods On the bases of FEM stress analysis of internal fixation of femur fractue with common compressing steel plate, 34 internal implant failures were reported. Results Besides the manipulation of operation and the limitation of internal implant itself, many factors such as the position and the length of steel plate, screws' not being set completely, improper selection of screw, gaps in bone cross - section, and defects of cortical bone all have important influence on the stability and safety of steel plate. Conclusion Biomechanical influence should be emphasized in the internal fixation of bone fracture, stress concentration should consider properly, so that the rigid and effective fixation function of internal implant could be ensured.

Abstract:随着组织工程的研究和临床应用的不断推进,种子细胞在载体表面粘附及随后的功能变化成了研究的重点。作者就细胞在载体表面粘附的基础研究及通过改进材料选择、制备、生物力学性质及对其进行表面修饰来促进细胞粘附和功能发挥的研究进展进行了综述,并介绍了制备理想组织工程骨所需解决的问题和未来的研究方向。