Abstract:Objective In the paper, the HHT method is adopted to deal with the wrist pulse signals collected from patientbodies. Methods nonlinear and nonstationary series can be decomposed by using the empirical mode decompositionmethod (EMD) into a number of intrinsic mode function (IMF) components. These components are transformed into thoseexpressions called HH spectra which exhibit the amplitude-frequency-time distributions of the data, and then the marginalspectra are obtained by integrating the HH spectra with respect to time. This is a new and applicable time series analysismethod based on mode decomposition. Results A time series constructed from a set of standard cyclic functions isfirst treated with using the EMD method to verify the applicability and effectiveness. And then, two pulse signals, onefrom a healthy person and the other from a patient suffering from the coronary heart disease are decomposed and theirresults are discussed. Conclusion The HHT method has broad prospects in the biomedical engineering and bioinformaticsapplications.

Abstract:Objective To select the preload and afterload of the silicone tube flow chamber to simulate the pulsatile fluidshear stress and circumferential stress under physiological conditions. Methods Based on in vivo pulsatile fluid shearstress and circumferential stress waveforms, the radius, pressure and flow waveforms in the silicone tube chamberwere inversely calculated in case of the geometrical and mechanical property of silicone tube flow chamber were given.The afterload, i.e. input impedance, of the silicone tube flow chamber was then determined based on the obtainedpressure and flow waveforms. Finally, the input impedance was simulated by a nine-element lumped parameter modelproposed by Z. G. Fung et al. Results The modulus and phase simulated by the nine-element lumped parameter modelcould fit the goal input impedance well. Conclusion The method and results provided a reliable theoretical base forselecting appropriate the preload and afterload of silicone tube flow chamber to construct a silicone tube flow chambersystem which would simulate arterial pulsatile fluid shear stress and circumferential stress environment.

Abstract:Objectives To unscramble the relation between biological action and cytoskeleton’s abnormity in tumor fromthe phenomenon that when A549 cell respons to strain morphological changes are induced. Methods A549 cell waschosen and an unidirectional equiaxial strain loading device in vitro was set up to apply cyclic stretch to the substrate ofthe cells, with the computer image processing and mathematical statistics. Results The results of the experiment wereanalyzed and compared with the contrast. It’s demonstrated that: 1. During the stretch course, the cells have presentedmorphologic changes clearly. The ratio of the long axis and short axis had increased obviously going with the cells spreadarea increased; 2. Nucleus spread area increased, the modality alteration which was induced by substrate stretch wasnot patency; 3. Cyclic stretch made orientation of the A549 cells change to the vertical direction of the stretch. Cells werestretched longer and linked head to tail in the form of a line. Conclusion: 1.The respondence of cytoskeleton componentsof A549 (mainly include cytoskeleton of membrane, cytoplasm and nucleus) to stretch are separate and unsynchronized;2. The respondence of A549 to the stretch is normal.

Abstract:Objective To investigate the Effect of low density lipoprotein (LDL) on endothelial cell adhesion in shearstress and its relationship with lipid and filamentous actin (F-actin). Methods The endothelial cells (ECV-304) wereincubated with different concentrations of low density lipoprotein (0 mg/L, 50 mg/L,100 mg/L,150 mg/L) for 24h. Thereafter,the content of cholesterol ester in endothelial cells was assayed with High Performance Liquid Chromatography (HPLC).The lipid within endothelial cells was detected with oil red O. F-actin was examined with fluorescence staining ofrhodamine-phalloidin. After treated with LDL, endothelial cells were subjected to flow shear stress of 15Pa for 24h.Results Compared to control, LDL significantly increased the ester level in endothelial cells (80.3±1.5 μg/g, 115.5±2.2μg/g and 160.6±3.2 μg/g to control 61.3±1.6 μg/g, p<0.05). Observation by fluorescence microscopy showed that thefibers of F-actin in normal endothelial cells concentrated along the cell membrane and no dense fibers were observed inthe cytoplasm. The abnormal F-actin were appeared in LDL-treated endothelial cells, while most of the peripheral fibersdisappeared and dense stress fibers were observed in the cytoplasm with high dose LDL. After exposed to 1.5 Pa shearstress the conformance and the adhesion of endothelial cells which incubated with 150 mg/L LDL decreased comparingwith control. Conclusion LDL causes lipid accumulation and the cytoplasm damaged, which may relate to endothelialcell conformance and adhesion.

Abstract:Objective To find out whether the TCP-PMMA cement can be used for artifical joint fixation . Methodstwenty-five rabbits were randomly divided into five groups, a standard hole whose diameter and length is 6 mm and 12mm respectively was made in the distal femur.one hole was filled with TCP-PMMA (the proportion of TCP in the TCP-PMMAwas 35% in weight),the opposite side was used as control,the hole was filled with pure PMMA cement. The shear stressof interface between the cement and bone were tested at 2,4 ,8,12 and 16 weeks postoperatively. Results The shearpowers were reduced slightly at 2 weeks postoperatively ,and increased gradually during observed period, especially at12 weeks and 16 weeks ,and larger obviously than before and control side. No change was found at control sides duringthe observed period . Conclusion The shear stress of the interface between the bone and TCP-PMMA was larger thanthat of pure PMMA cement.

Abstract:Objective TO design a set of bioreactor which can construct well morphological and mechanicalperformance tissue engineered tendons. Methods According to the biomechanics and environment of tendon exist invivo, a model for compound of cells and biodegradable material was set up and a set of bioreactor which can simulatebiomechanical environment was designed. Avian tendon cell-PGA sheets were cultured in dishes during the first twoweeks. The constructs that received cyclical stretch served as experimental group, while unloaded constructs servedas control group. Specimens were harvested for gross examination, H&E staining and biomechanical test. ResultsTendon like tissue can be got under continuous and pulsatile mechanical during the cell culture in vitro. From evaluationsbetter results was proved in experimental group than control group. Conclusions mechanical model has bothcorrectness and some limits. Stress can accelerate cell matrix secret. Viscoelastic material, such as compound of celland biodegradable material, has instantaneous deformation by unvarying stress and strain increase linearly with time.Creep play an important role in collagen fibril parallel arrangement.

Abstract:Objective To investigate the property of collagen molecule assembling during the bone formation whencollagen molecules was excreted by osteoblasts; Methods Quantum Mechanics software Gaussian03 is applied inthe modeling of the stretch force-length curves of the cross-link between tropocollagen. Results The curve obtainedis non-linear , the start distance (energy optimized) of the two α carbon atoms is 10.05 ?. When the length reaches 130%of the start length, be 13.05 ?, an apparent turn appears on the force-length curve. The slope of the curve posterior tothe turn is much greater than that of the anterior; The maximum length is 16.05 ? when fracture take place; The stretchforce reaches the highest value 5622 pN; Break take place between α carbon atom and β carbon atom of the hydroxylysineresidue of the cross-link; Conclusion The mechanical characteristics of the cross-link predicted here by quantummechanics modeling need experimental corroboration.

Abstract:Objective To evaluate the contractility of left ventricule due to cardiac remodeling in hypertension by meansof maximum myocardial stiffness(maxEav). Method The end-systolic and end-diastolic dimension of left ventricule, leftventricular mass index (LVMI) , relative wall thickness (RWT) , ejection fraction(EF) and short-axis shorting fraction(FS)were measured by echocardiography in 96 patients with essential hypertension and 30 normal subjects.Left ventriculeend-systolic pressure was evaluated by sphygmomanometer. Essential hypertensions were divided into groups with LVnormal geometric patterns,LV concentric remodeling patterns,LV concentric hypertrophy patterns and LV eccentrichypertrophy patterns according to the LVMI and RWT. Maximum myocardial stiffness(maxEav)was calculated by usingof echocardiographic measurements. Result ① There were not significant differcences of LV systolic functionbetween control group and hypertension groups (P>0.05); ② maxEav of hypertension patients was significantly largerthan that of control group(P<0.01 ); but there were not differences between hypertension groups (P>0.05). ConclusionMaximum myocardial stiffness maxEav derived by echocardiography is noninvasive method and worthful for evaluatingthe biomechanical characteristic of LV remodeling due to hypertension.

Abstract:Objective (1) To investigate the effect of the extended distance of the arms of shape memory alloysawtooth-arm fixator(SSEF) on the embracing force of SSEF. (2)To investigate the effect of the ratio of the diameter ofthe fractured bone to the inner diameter of the SSEF on the embracing force of SSEF. Method (1)Getting a series ofsmall steel rod made of 1-Cr-13 steel with the diameter of 5mm and the length of 27 mm, 28 mm, 29 mm, 30 mm, 31 mm,32 mm, 33 mm. Getting a plane with the width of 3 mm out of each steel rod to stick the strain gages on ,pressurizing.(2)Utilizing the different pressure sensors to simulate the different bones with different diameters .Extending the free endsof the two arms to different distance and then putting SSEF in a electronic container in which the temperature can beadjusted.While the temperature of the SSEF is increasing the SSEF tends to recover its original shape , so the two armspress the pressure sensor making the steel rod get a little decrease in the length which can be measured by the YJ-35instrument. (3)Utilizing the SAS to analyze the data we got. Results (1) The SSEF’s embracing force is decreasingalong with the extended distance of the arms of SSEF increasing.(2)The embracing force is the largest with the steel roadof 32 mm inside the arms of SSEF with the diameter of 27 mm. Conclusion (1) In surgery, the free ends of the arms ofSSEF should just be extended to the distance at which it can be put on the fracture bone and try to avoid being extendedto a very large distance. (2)The diameter of SSEF=0.87×the diameter of the bone, we can refer to this formula wheneverwe have to choose a suitable size of SSEF to fix the bone fracture.

Abstract:Object To evaluate the biomechanics of several groups of femoral prothesis stems matched with a femur,and get a stem which mechanics distribution nearly to normal femur from these stems. Methods The image files withbmp format of the proximal femur X ray and four groups femur- prothesis templat matched with the femur were introduced,and the bi-dimension contour data of femur and femur matched with the template were extracted respectively ,we madeuse of the sofe of ANSYS to establish the model of geometrical and bi-dimesion nonlierarity Finite Element including femurand femur-femoral stem, the condition of stress distribution in proximal femur was analysised and compared by loading.Results After the stem was inset, the stress distribution and value in proximal femur were different from normalfemurobviously, but in four groups stems ,there was a stem which stress distribution and value in proximal femur nearlyto normal femur at last and the stem’s biomechanics property was superior to the others’ in the femur. Conclusion Byanalying and comparing the biomechanics of the femoral prothesis based on X-ray and template, the property ofbiomechanics of femoral prothesis has been evaluated to offer basis for super-selection prothesis.

Abstract:Objective The purpose of this study was to investigate the affect of cervical spinal column posture andprior loading history on its motor unit compressive strength. Method 12 fresh human cadaver cervical spines wereharvested and dissected into 24 motion segments containing two vertebrae and the intervening disc (C34 and C56).Compressive loads were applied so that the effects of the limited compressive strength by the two loading historiesdehydrated and two failure postures (neutral, flexed) on the spine could be examined. Dissection techniques were usedto document tissue damage. Result Specimens in a flexed posture had a lower ultimate compressive strength(27%42%, P<0.001) than in a neutral posture. When in a neutral posture, super-hydrated specimens had a lowerstrength (29%, P<0.01) than dehydrated specimens. Conclusion The spine may be more prone to get injury early in themorning when the discs are at their t greatest level of hydration with a fully flexed posture.

Abstract:Objective To measure and compare the insertion torque and pullout strength of newly-designed expansivespinal fixation system(ESS) pedicle screws with those of CD-II and GSS pedicle screws in normal human cadaververtebrae, and to evaluate the screw purchase of ESS pedicle screws. Methods Thirty lumbar vertebral bodiesobtained from 6 fresh normal male cadavers were classified into 3 groups randomly, 20 pedicles per group. ESS, CD-￠?,and GSS pedicle screws were implanted into the pedicles of each group respectively. The 34 last screw circles of eachpedicle screw were remained. The remained screw circles were implanted by using a material-testing machine (SWD-10,Changchun, China) to measure the insertion torque. Then each screw was extracted axially from the pedicle at a rate of5mm/min until failure by using the same machine. Force data were recorded and analyzed using a one-way ANOVA andLSD. P<0.05 was considered significant. Results The torques of the ESS, CD-II, and GSS screws were (5.79±1.85)Nm, (5.19? ?0.75)Nm, and (5.56±1.31)Nm respectively. The pullout strength of the ESS, CD-II, and GSS were (2219.80±367.60)N, (1630.65±392.58)N, and (1963.75±403.68)N respectively. The maximum axial pullout strength of ESS wasgreater than that of CD-II and GSS screws. The pullout strength difference was very significant between ESS and CD-II (P<0.001), was significant between ESS and GSS (p<0.05). Insertion torque was correlated positively with pulloutstrength between the ESS and CD-II pedicle screws (p<0.01). Conclusions ESS pedicles screws have good purchaseability, better than that of CD-II and GSS pedicle screws.

Abstract:Obejective To quantitatively research the deformation distribution of the outside pelvis around the replacedartificial acetabulum joint under static loads. Methods Digital image correlation is used to measure full-field surfacedeformation of test part. Results The deformation state is nonhomogenous and complicated. Conculsion Digitalimage correlation is a prospective non-contact full field optical technique to be used in biology mechanics.

Abstract:Objective Did research on normal countrymen flexor digiti minimi tendon simulation traumata kiss connectme with skill rear mechanical property, supply biomechanics parameter with clinical. Method Get the twenty loaf wholehand specimen of the TAKEN acuteness header traumata killing adult fresh cadaver, dissection expose flexor digiti minimitendon to adopt electron universal testing machine proceed tension test till flexor disinsertion (I group), then cent twogroup, parting with tendon and tendon terminal wove dovetail (II group, 10 example), and tendon and unfold aponeurosesterminal wove dovetail (III group, 10 example), and then proceed stretch experiment result in rupture. record creackingload, stress, strain on the breaking time. Result The normal group (I group) cracking load is 237.4 N, stress is 24.5 MPa,strain is 12.6%; II group is parting for 100.6 N, 20.4 MPa, 11.5%; III group is parting for 63 N, 12.6 MPa, 14.7%. ConclusionBe little finger rupture of tendon withal tendon-tendon terminal wove dovetail be able to procure optimal mechanics effect,fit to clinical adopt.

Abstract:Objective Burst fractures are the most common injury in the thoracolumbar spine, which often cause aneurological deficit and present a significant economic burden to family and society. Biomechanical investigations,including in validation of injury mechanism theories, instrumentation systems, and reduction techniques, could provide abetter understanding of thoracolumbar burst Fractures. The ideal burst fracture model is essential to these studies. Thegoal of this review article is to improve understanding about the thoracolumbar burst fracture model.

Abstract:The soft tissue balancing has great affection to the joint function after total hip arthroplasty and the adjustmentof the femoral offset is the main means to obtain the balance of the soft tissue. In this article, the relationship between theabductor muscle strength and femoral offset, the methods of increasing the offset and its results are reviewed.

Abstract:The primary blast injury of a living body occurs as a direct effect of changes in ambient pressure caused bya blast wave. The development of bio-shock tubes and other blast generators has given an enormous impetus to theexperimental researches of the primary blast injury in the laboratory. Various animals, isolated organs, as well as culturedcells were exposed to blast waves, so that a large body of experimental results of primary blast injury were obtained. Thepresent review first briefly describes the basic physics of blast waves, and then addresses the bio-shock tubes and theapproaches to experimental studies on the primary blast injury.