Abstract:The function of our research paper is to introduce new methodologies,results or theories obtained or derived from our research.The targetjournals for publication should be those SCI journals with the large readership.Except novel in research ideas and potential applications,the solid writing skills and scientific languages(e.g.English of the most SCI journals) is the key to get research papers accepted for publication.This paper introduces the essentials of manuscript preparation and submission for SCI journals and publications.We hope that this would be helpful for increasing quality of our manuscripts and their acceptance in the peer-reviewed journals.

Abstract:Purpose To explore the variation of contact characteristics of acetabular posterior wall fracture and its internal fixation.Methods Contact areas and contact stress of normal acetabulum group、acetabular posterior wall fracture group and two methods of internal fixation groups(reconstruction plate alone and spike plate with reconstruction plate) were measured by the application of pressure film,respectively.Results Compared with normal acetabulum group, contact area of acetabular posterior wall fracture group decreased by 34%,and recovered by 82% with reconstruction plate alone,and which spike plate group regained 92% contact area.Acetabular contact pressure and contact stress both increased obviously in acetabular posterior wall fracture group,and showed decrease after the fractures were fixed by the two internal fixation methods.Conclusions Contact areas of acetabular posterior wall fracture group greatly decreased to cause stress concentration.Two methods of internal fixation effectively made the acetabular contact areas recovered and reduced contact stress.Spike plate group were more effective compared to reconstruction plate alone group.

Abstract:Objective To construct small-sized tissue-engineered blood vessels with hBMSCs(human Bone Marrow Stromal Stem Cells)in our improved bioreactor system.Methods A set of bioreactor system was designed with the application of Finite Element Methods as an analysis method to construct tissue engineered blood vessels with the diameter of 2mm.hBMSCs were first collected and further cultivated.The third passage of the cultivated cells were then seeded on the polyglycolic acid(PGA)to fabricate the cell-scaffold compound.This compound was subsequently subjected to dynamical culturing in the blood vessel bioreactor.Results Tissue-engineered blood vessels can be constructed by culturing the hBMSCs-PGA compound under a dynamic condition.After 4 weeks,the tissues were removed from the bioreactor and subjected to analysis by visual observation,HE,SEM(scanning electron microscope) and immunohistochemistry for smooth muscleα-Actin.It was observed that the tissue-engineered blood vessel appeared bright color and has certain elasticity.The secreted collagen matrix arrayed orderly around the cells and smooth muscle elastic actin can also be detected in the formed tissues.Conclusion The in vivo biological conditions of blood vessels can be simulated using the current blood vessel bioreactor system.Using hBMSCs,the construction of the tissue engineered small-sized blood vessels can be successfully achieved in our bioreactor system.

Abstract:Objectives Using FX-4000 strain unit,the viscoelasticity of human lung adenocarcinoma A549 cells that underwent mechanical strain of different elongation amplitude were studied.Methods A micropipette aspiration technique was adopted to investigate the viscoelasticity of A549 cells,compared with 15% elongation -treated cells and 1.5% elongation-treated cells.A standard linear solid model was employed to fit the experimental data and three viscoelastic coefficients were used to compare the mechanical properties of control cells,15% elongation-treated cells and 1.5% elongation-treated cells.Results Viscoelastic coefficients k_1,k_2 andμvalue all reduced after A549 cells were subjected to 15% elongation with sine wave at frequency 0.5Hz for 4h compared with the control group,while the viscoelastic coefficients had no distinct difference compared with that in 1.5% elongation -treated cells.Conclusion The deformability increases and the rigidity decreases could be found for 15% elongation-treated cells.Such changes in the viscoelastic properties of cancer cells probably affect tumor cell invasion or metastasis as well as interaction between tumor cells and their micro-mechanical environment.

Abstract:Objective To study the effect of asymmetric inlet velocity profile on the wall shear stress of the position where atherosclerosis always happens.Methods Special software is used to construct the TF-AHCB model,set the asymmetric inlet velocity profile,and do the mesh dividing and the simulation work.The flow field of sinus and the distribution of wall shear stress on the different conditions of time and inlet velocity are calculated.The feature of flow field and shear stress which is related to the atherosclerosis is analyzed.Result Asymmetric inlet velocity profile deflexion could increase the area of low shear stress and the gradient of shear stress.Conclusion Asymmetric inlet velocity profile could be one of the dangerous factor to cause atherosclerosis.

Abstract:Objective Try to find out the best graft-host diameter ratio and junction angle that can furthest improve success rate in coronary artery bypass graft(CABG).Method ANSYS9.0 was used to simulate CABG,and response surface methodology(RSM)was applied to construct the mathematical model,last theory of optimization was performed to search the optimum graft-host diameter ratio and junction angle which can make the primary factor influencing success rate-wall shear stress gradient(WSSG)to be the smallest.Result The model with large graft-host diameter ratio and small junction angle has better hemodynamics feature in CABG.Conclusion There are many factors influencing success rate in CABG,at present,it is advisable to adopt graft-host diameter ratio as large as possible and junction angle as small as possible with help of clinic experience.

Abstract:Objective Clinical research,animal and simulation experiments have revealed that the myocardial bridge presses mural coronary artery,which leads to the changes of the rate of flow and pressures of mural coronary artery, and results in special homodynamic phenomenon.This paper discusses the mechanism of this phenomenon in the proximal part of the myocardial bridge using water hammer theory.Methods The hemodynamical characteristics of mural coronary artery were simulated using a simulated apparatus.The pressures and velocities in the proximal part of the myocardial bridge were measured in middle of systole and at the beginning of diastole.One-dimensional water hammer theory was used and compared with the data of experiments.Results Theoretical elevates of systolic pressures and diastolic velocities of the mural coronary artery basically agree with the data of measurements.Conclusion The mechanical mechanism of special phenomenon of mural coronary artery can be explained using water hammer theory.

Abstract:Objective To investigate the effect of simvastain on the biomechanical characteristics of femur in ovariectomized rats.Methods 48 female SD Rats were randomized divided into three groups:Sham-operated group (S),ovariectomized group(OVX)and Simvastatin ovariectomized rats group(OVX+SIM).8 weeks later,Simvastatin were administered orallywith 5mg·kg-1·d-1 to OVX+SIM group and normal saline to the other two groups.The rats were killed separately 4 weeks and 12 weeks after operation.The femora were taken out for the three-point bending test to measure the maximal loading,flexibility loading,flexibility strain,maximal strain,coefficient of bending stiffness,coefficient of bending ductility of the femur.Results(1)The maximal loading and the maximal strain of femur in SHAM group was significantly higher than that in the OVX group(P<0.05)at 4 weeks after treatment.The coefficient of bending ductility of the femur in the OVX+SIM group was significantly higher than that in the OVX group(P<0.01)while the the flexibility loading of the femur in OVX+SIM group was significantly lower than that in the OVX group(P<0.05)at 4 weeks after treatment.(2)12 weeks after treatment,the maximal loading of the femur in the OVX+SIM group or that in the SHAM group was significantly higher than that in the OVX group(P<0.05,P<0.01),the flexibility loading of the femur in the OVX+SIM group was significantly higher than that in the OVX group(P<0.05),the coefficient of bending ductility of the femur in the OVX+SIM group or that in the SHAM group was significantly lower than that in the OVX group(P<0.05,P<0.01);(3)The maximal loading of the OVX+SIM group,the flexibility loading of the OVX+SIM group￡﹁or the coefficient of bending ductility of the OVX group at 12 weeks after treatment was significant higher than that at 4 weeks after treatment with statistically significant(P<0.01).Conclusion Simvastain could affect the bone remodeling and improve the biomechanical properties characteristics of the femur of the ovariectomized rats.

Abstract:Objective Using CrySegmentation software developed by Institute of Life Quality & Mechanical Engineering to distill the boundary of human bone from Cryo-cadaver,using reverse engineering software Imageware to establish the surface model of lumbar,and then using ANSYS to establish 3D finite element model.Methods Using the first male cryosection data from The Third Military Medical University for Cryosection image processing,and then for the contour line of section information processing.Results 3D finite element model of lumbar with all anatomical characteristic could be established quickly in this way.Conclusion Using CrySegmentation developed by Institute of Life Quality & Mechanical Engineering and some commercial software can precisely and quickly establish surface model,solid model & 3D finite element model of human lumbar to supply the original model based-on anatomy for the purpose of digital simulation and dynamical simulation in the different domain such as aviation,vehicle,shipping,biomedicine engineering,etc.

Abstract:Objective To acquire the skeletal-muscle抯 stress-strain constitutive equation with various strain rate. Methods In the base of hill's three factors muscle model,this paper uses the method of differential coefficient and linear approach.Results When the strain rate lel≤1,the skeletal-muscle's constitutive equation is different to various strain rate;when the strain rate lel>1,the skeletal-muscle's constitutive equation couldn't be influenced by various strain rate. At the same time,when lel≤1,the influence of the strain rate to the stress is continuously decreasing with the strain increasing.Conclusion The acquired constitutive equation is helpful in using finite method analysing the skeletal- muscle's stress condition with various strain rate.

Abstract:Objective To make some revisions on the planimetric model of unipennate skeletal muscle,as well as Otten's mechanical analysis since Otten only considered the equilibrium of the aponeurosis(local equilibrium)and made too much simplification on the intramuscular pressure.Method The new method in this paper is based on the mechanical equilibrium of whole muscle and a volume-related force is introduced to keep muscle volume constant. Mechanical equilibrium of whole muscle yields a different relation between fiber and muscle force,compared to relations derived when only equilibrium of aponeurosis is considered.Results The newly derived relation improves prediction of the rat gastrocnemius muscle force-length characteristics.Conclusion The prediction of muscle force-length characteristics is very good with a simple model such as a planimetric model,which suggests that the influence of properties neglected in such a simple model is either small or internally compensated in the net effects.

Abstract:Objective In order to improve biomechanics compatibilities of implant materials,the effect of SMAT process on mechanical properties of pure Ti has been studied.Methods Mechanical tests have been carried out to analyze the SMAT effect on mechanical properties of pure Ti after the 1mm thick Ti sheet was subjected to SMAT process.Results After SMAT process,the surface of pure Ti has been nanolized and the body has been converted into a gradient material. The study results show that SMAT process has made the Ti's strength increase,its plasticity decrease while the microhardness in its surface layer increase greatly.The most important is that the Ti's elastic modulus has decreased significantly which can improve Ti's biomechanics compatibility.Conclusion SMAT process is able to nanolize Ti's surface,which can decrease Ti's elastic modulus and improve Ti's biomechanics compatibility to make it promising in biomedical application.

Abstract:Objective To analyze and probe into changes of cerebral vascular hemodynamic indexes(CVHI)before stroke,in order to provide references for identifying individuals in high risk of stroke.Methods 200 newly occurred stroke patients,after baseline investigation and CVHI detection,in a cohort during follow up were defined as experimental group.227 stroke patients,in the same population and occurred within one year before baseline investigation,were defined as control group.Differences of CVHI and its accumulative scores were compared between two groups. Results kinematics indexes in experimental group were lower than that in control group.While,dynamic indexes were higher than that in controls at large.A part from Vmin and cp,significant differences of all other indexes were found between two groups.Means of the accumulative score in experimental and control group were 51.32±31.37 and 58. 44+31.63,respectively(P<0.05).Conclusions The study indicates that injury degree of cerebrovascular hemodynamic before stroke is rather than these with stroke history within one year.It seems as an important warning indicator.

Abstract:Objective Design a newtype bone plate PC-LCP and determine its mechanical properties and the biomechanical stability.Method Four point bending test was conducted to determine the mechanical properties of each of the 3 pairs of PC-LCP、LC-DCP、DCP;using 20 pairs of new fresh sheep tibia,mid-shaft transverse fracture were created and fixed with PC-LCP、LC-DCP、DCP,respectively;and then the four point bending、torsion and axial compress tests were conducted to determine the bending、torsion and axial compress stiffness.Result Although the bending stiffness of PC-LCP is less than that of DCP,LC-DCP and have significant difference,the biomechanical properties of fixed fracture bone by these three type bone plate showed no significant difference.Conclusion The new PC-LCP has the similar biomechanical properties as the other two type plates when used to fix the broken bone and has the adequate stability.

Abstract:Objective To explore the effect of hip surface replacement on the mechanical characteristics of proximal femur.Method Eight cases of young fresh normal femoral specimens were selected and one leg in standing position was used in the measurement.The biomechanical test was performed on the WD-5 type machine to detect the relation of loading and strain,distribution of stress,rigidity,torsion of normal proximal femur and resurfaced proximal femur under the loading of 1000N.Result No significant difference was found in the relation of loading and strain,distribution of stress and rigidity between normal proximal femur and proximal femur with surface replacement.The maximal torsion between normal proximal femur and proximal femur with surface replacement was 19%,which showed significant differences.Conclusion The hip surface replacement could maintain normal transfer of load to the proximal femur,and avoid resorption resulting from stress shielding similar to THA,therefore it can preserve the proximal bone stock around femoral stem and make the consequent revision easy.It is an effective solution suitable for young patients.

Abstract:Objective To evaluate the biomechanical effects of nucleotomy with two procedures on the stability of lumbar spine and the highest von Mises stress in annulus.Method A three-dimensional finite element model of L4-5 motion segment was established by using CT scans.Nucleotomy through osseous lamina fenestration and through interlaminar fenestration was simulated on the model,respectively,and axial compressive load of 400N with moment of 6.0Nm in six directions,including flexion,extension,left and right lateral bending,left and right axial torsion,were employed on the models.Rotational degrees of inter-segment and the highest von Mises stress in annulus were examined. Result After nucleotomy through osseous lamina fenestration,the rotational degrees of inter-segment in flexion and extention conditions increased by 31% and 28%,respectively;the highest von Mises stress in annulus increased by 16% and 6%,respectively.After nucleotomy through interlaminar fenestration,the rotational degrees of inter-segment in flexion and extention conditions increased by 33% and 39%,respectively;the highest von Mises stress in annulus increased by 17% and 0.2%,respectively.After nucleotomy with the two procedures,the stress distribution in annulus keeps unchanged,but the stress values increased in all cases.Conclusion Contrast to nucleotomy through interlaminar fenestration,nucleotomy through osseous lamina fenestration can keep the lumbar spine more stable in extension condition,but the increase of stress in annulus is higher in the same condition.

Abstract:Objective To compare the stability of the lumbar intervertebral segmental stiffness after three types of interbody fusion(ALIF,PLIF and TLIF)with or without lateral transpedicular screws fixation.Methods Fifteen bovine lumbers were divided into 7 groups,with each performed nondestructive tests.Results(1)Comparing with the intact group,the mean axis compression stiffness decreased by 28.3%,18.4%,11.5% (P<0.05),respectively;the mean anteroposterior shear stiffness decreased by 21.6%,17.5%,5.9% (P<0.05),respectively in ALIF(1) 2PLIF(1)and TLIF(1)group;the axial rotational stiffness decreased by 38.6%,49.1%,27.2%,respectively(2)By applying internal fixation,comparing with the non-internal fixation interbody fusion group,their mean axis compression stiffness and anteroposterior were separately increased by 87.8%,77.9%,75.9%(P<0.05)and 60.6%,68.1%,63.1%(P<0.05), respectively;Their axial rotational stiffness increased by 95.1%,110.9%,87.6% (P<0.05),respectively.Conclusion (1)Three types of Lumbar interbody fusion without additional internal fixation showed less stable than the normal intact lumbar.Only when transpedicular screws fixation applied,their stability could increased greatly and become much more stable than normal intact lumbar.(2)TLIF is the most stable one in the three types.