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  • 1  Application of atomic force microscopy in ultrastructure and biomechanics of cells and biomacromolecules
    ZHU Jie GUO Lian-hong WANG Guo-dong OUYANG Wu-qing
    2012, 27(3):355-360. DOI: 10.3871/j.1004-7220.2012.03.360.
    [Abstract](8718) [HTML](0) [PDF 12.98 M](22730)
    Abstract:
    To be the representative fruition resulted from the rapid development in micro-nano theory and technology, atomic force microscopy (AFM) has greatly promoted the expansion of biological research in micro-nano scale, and facilitated the birth and development of micro-nano biology as an important technique in its 25-year evolutional progress. Based on the fundamental principles and detection modes of AFM, as well as the author’s research findings and work experience in this field, the paper reviews the application of AFM in the study on ultrastructure and biomechanical properties of cells and biomacromolecules in the aspects of biological structure and morphology, surface physicochemical characterization and mechanical manipulation of biological macromolecules, and focus on some important scientific and technical problems on AFM in micro-nano biomedical research needed to be improved and solved urgently, with exploratory insights and recommendations for potential users in ultrastructure and biomechanics of cells and biomacromolecules.
    2  Finite element analysis on mechanical responses of human torso with body armor to non penetrating ballistic impact
    DONG Ping CHEN Jing ZHANG Qi-kuan KANG Jian-yi LIU Hai ZHANG Liang-chao XU Cheng
    2012, 27(3):270-275. DOI: 10.3871/j.1004-7220.2012.03.275.
    [Abstract](9223) [HTML](0) [PDF 12.44 M](14588)
    Abstract:
    ObjectiveTo develop a finite element computational model of the torso for the numerical simulation of mechanical responses of human torso to non-penetrating ballistic impact. MethodsBased on the CT data of a Chinese adult man, the finite element model of human torso was created by using the medical image processing software Mimics and the finite element pre-processing software HyperMesh. The pressure and acceleration response of the human torso outfitted with soft body armor to the ballistic impact from 9 mm ammunition at a velocity of 360 m/s was calculated numerically by the explicit finite element code LS-DYNA. ResultsThe finite element model of human torso including thoracic skeletal structure, organs, mediastinum and muscle/skin was established. The pressure response of heart, lung, liver and stomach, as well as the acceleration response of sternum were obtained by numerical calculation. It was found that the peak pressure and its time phase were dependent on the distance between the impact point and the measured point wherever in various organs or different position of an organ. Conclusions The finite element computational model of human torso outfitted with soft body armor is available for the simulation of human response to non-penetrating ballistic impact, and the simulated response can be used as evidence for the investigation on mechanism and protection of behind armor blunt frauma.
    3  Influences of cyclic tensile strain on proliferation of preosteoclasts and osteoclasts and tartrate resistant acid phosphatage
    GUO Yong GUO Chun YAN Yu-xian LI Rui-xin LIU Lu HAO Qing-xin ZHANG Xi-zheng SHI Cai-hong
    2012, 27(3):299-304. DOI: 10.3871/j.1004-7220.2012.03.304.
    [Abstract](7630) [HTML](0) [PDF 19.90 M](11039)
    Abstract:
    Objective To investigate the effect of mechanical loading with different magnitudes on the proliferation, differentiation and activity of preosteoclasts and osteoclasts. Methods One group of RAW264.7 preosteoclastic cells cultured in osteoclast inductive medium were subjected to the cyclic tensile strain for three days, and then cultured for four days; the other group of RAW264.7 cells were induced in osteoclast inductive medium for four days to be osteoclasts, then subjected to the cyclic tensile strain for three days. Results Under the tensile strain at different magnitudes, the proliferation variations in two groups of RAW264.7 cells were approximately identical, but changes in the activities of tartrate-resistant acid phosphatage (TRAP) and numbers of TRAP-positive multinucleated cells (osteoclasts) in the two groups were significantly different. Under the moderate tensile strain (2 500 με), the reduction of TRAP activity and osteoclasts number were both the highest in the first group, and both the lowest in the second group. Conclusions The influence of different tensile strain on osteoclast differentiation and osteoclastic activity of preosteoclasts in early differentiation is different to that of the preosteoclasts already differentiated into osteoclasts.
    4  Relationship between mineral density and elastic modulus of human cancellous bone
    WANG Jing LI Yuan-chao WANG Fang WANG Qiu-gen WANG Dong-mei
    2014, 29(5):465-470. DOI: 10.3871/j.1004-7220.2014.05.470.
    [Abstract](5124) [HTML](0) [PDF 866.94 K](6701)
    Abstract:
    Objective To measure the cancellous bone mineral density and axial elastic modulus from multiple anatomic sites, then build the constitutive equation between them, so as to provide specific data for finite element modeling of Chinese people. Methods Ten fresh adult cadavers were taken as sample sources. In every fresh cadaver, 5 different anatomic sites were selected: proximal tibia, greater trochanter, femoral neck, humeral head and lumbar vertebra. The raw samples were processed into standard specimens, which were approximately 6 mm in diameter and 30 mm or 40 mm in length. Both the size and volume for the cancellous bone specimens were measured, and their mineral densities were obtained with computed tomography. The mechanical properties of such specimens were tested with biomechanical testing machine for analyzing the elastic modulus of the cancellous bone at different anatomic sites. The linear and power regression between mineral density and axial elastic modulus were analyzed on SPSS 18.0. Results A total of 169 cancellous bone specimens which were availably tested were collected, including 52 proximal tibia, 31 greater trochanter, 15 femoral neck, 17 humeral head and 54 lumbar vertebrae. The analysis on measurement results showed that the mineral density and axial elastic modulus in cancellous bones from 5 anatomic sites were different, and had a solid linear relationship (0.850>r2>0.785), with 3 sites (proximal tibia, greater trochanter, lumbar vertebra) showing a solid power correlation (0.871>r2>0.825), and the other 2 sites (humeral head and femoral neck) showing relatively weak power correlation (0.671>r2>0.643). Conclusions There are solid linear and power relationship between mineral density and axial elastic modulus, while no significant difference is proved between the r2 values of the two regressions in this research. This discovery can be applied to detect patients’ bone quality in vitro and identify the precise position of bone loss, and further to predict fracture risk with the help of finite element modeling.
    5  Fatigue Life Analysis of Coronary Stent
    LI Jian-jun LUO Qi-yi XIE Zhi-yong LI Yu
    2010, 25(1):68-73. DOI: 10.3871/j.1004-7220.2010.01.73.
    [Abstract](10188) [HTML](0) [PDF 709.16 K](6636)
    Abstract:
    Abstract Objective After the implantation, coronary stent was expected at least to keep integrity and maintain the predicated function for over 10 years or 4e8 cycles under the pulsatile loading conditions, and the fatigue property of the stent should be evaluated. Method The finite method was used to analyze the stress distribution of different phases and evaluate the fatigue life according to Goodman criteria, meanwhile, the accelerated fatigue experiment was also performed . Results It could be concluded that the dangerous points were located in the lateral inner surface of stent curvature. Conclusion The results proved that the fatigue property could be simulated through the finite element analysis, which can provide the theoretical guidance for the stent design.
    6  Biomechanics of lumbar spondylolysis : Finite element modeling and validation
    GU Xiao-min JIA Lian-shun CHEN Xiong-sheng LU Cheng-lin LIU Yang ZHANG Dong-sheng
    2010, 25(1):45-50. DOI: 10.3871/j.1004-7220.2010.1.50.
    [Abstract](9595) [HTML](0) [PDF 749.69 K](5986)
    Abstract:
    Objectives To construct three-dimensional finite element model of lumbar spondylolysis, then to verify its validity by comparison of biomechanics in vitro. Methods According to the radiological data of a patient with lumbar spondylolysis, the bone and intervertebral disc of L4-S1 were reconstructed by Simpleware software. The lumbar attaching ligaments and articular capsule were added into simulating model by Ansys software. Finally, the three-dimensional finite element model of lumbar spondylolysis was simulated successfully, and validated by lumbar spondylolysis biomechanical experiment in vitro. Results The reconstruction of digital model is contained of the bones of lumbar spine which includes of vertebral cortical bone, cancellous bone, facet joint, pedicle, lamina, transverse process and spinous process,as well as annulus fibrosus, nucleus pulposus,superior and inferior end-plates. Besides, anterior and posterior longitudinal ligaments, flavum ligament, supraspinal and interspinal ligaments and articular capsule of facet joint are also attached. The model consisted of 281,261 nodes and 661,150 elements. Imitation of spondylolysis is well done in this model. The validity of the model is verify by comparison of the results of biomechanics in vitro which involved in the trends under loading of stress/strain of L4 inferior facet process, L5 superior and inferior facet process, S1 superior facet process and the trend of stress/strain of lateral and medial L4 inferior facet process. Conclusions Lumbar spondylolysis is reconstructed to three-dimensional model using finite element analysis, and can be further used in the research of biomechanics of lumbar spondylolysis.
    7  Status and progress of tissue engineering research
    ZHANG Xi-zheng
    2010, 25(1):1-3. DOI: 10.3871/j.1004-7220.2010.1.3.
    [Abstract](10121) [HTML](0) [PDF 404.53 K](5614)
    Abstract:
    Tissue engineering is one of the most promising subjects,which has broad application prospects in the fields of regenerative medicine and human health care. According to the papers published in this current issue about scaffold material preparation and mechanical environment affection to cells during the construction process of tissue engineering, this paper describes the current status and progress of tissue engineering research at home and abroad, indicating that tissue engineering research is developing to a deeper and wider field.
    8  Effects of adhesive thickness on internal stress distribution in full-ceramic crowns
    LIN Bin LU Cheng-lin ZHANG Xiu-yin ZHANG Dong-sheng
    2010, 25(1):56-62. DOI: 10.3871/j.1004-7220.2010.01.62.
    [Abstract](9881) [HTML](0) [PDF 768.15 K](5241)
    Abstract:
    Objective The objective of this study is to investigate the effects of the thickness of the adhesives (3M ESPE RelyX ARC) on the internal stress distribution of the IPS Empress II full-ceramic crowns using Finite Element Analysis (FEA). Methods A dummy Empress II ceramic crown restoration of the mandible right first molar was prepared according to standard dental process. Followed by micro-CT scanning, four 3D numerical models with cement thickness 60, 90, 120 and 150μm were established. The models were subjected to four loading conditions and stresses in veneer and core layers were presented. Results Numerical results indicate that when adhesive thickness increases from 60μm to 90μm, the maximum principal stress either in veneer or core decreases. However, when thickness increases to 150μm, stress variation trends differ from adhesives. Conclusion The normal stresses in adhesives remain a low level when the thickness varies from 90μm to 120μm, while the shear stress is less sensitive to the thickness when it exceeds 90μm. There is an optimal thickness which can reduce the tensile stress in the core and veneer. Attention should be paid to the shear strength of the adhesives since the shear stress could cause failure in the adhesive layer.
    9  Preparation and Characteristics of Patterned TiO2 Thin Film onTC4 Made by Sol-gel Method
    LIU Ying ZHANG Wen-guang
    2010, 25(1):21-25. DOI: 10.3871/j.1004-7220.2010.1.25.
    [Abstract](7201) [HTML](0) [PDF 567.23 K](5237)
    Abstract:
    Objective To improve the long-term biocompatibility and mechanical stability of Titanium alloy implants. Method micro-nano patterned TiO2 thin films have been prepared on TC4 substrates via a sol-gel dip-coating method with Ti(OC4H9)4 (TEOT) as precursor and polyethylene glycol (PEG) as organic template. The influence of PEG concentration upon the morphology of the target films has been studied by using AFM. The wettability and tribological properties of the target films have been studied by means of optical contact angle measuring instrument and UMT-2. Results When increasing the PEG concentration to 3.5g/100mL, a parallel arranged groove structure can be obtained on the surface of the sample; compare with TiO2 sol-gel film without adding organic template, the wear resistance of the patterned film is better. Conclusions The feature of the patterned TiO2 films can be controlled by adding different amount of organic template; and it has been proved that a certain kind of patterned structure can improve the wear resistance of the film.
    10  Three-dimensional finite element numerical analysis of the Ni Ti shape memory alloy clutching internal fixator
    CHEN Guo-ping FAN Yu-bo ZHANG Dai-quan
    2010, 25(1):36-39. DOI: 10.3871/j.1004-7220.2010.1.39.
    [Abstract](7362) [HTML](0) [PDF 448.75 K](5159)
    Abstract:
    Objective Clutching internal fixtor (CIF) loose and the fixed part weakly heal up are often found in orthopedic clinic.In the present paper, biomechanics methods were used to try to explain and analyze these issues, provide a helpful suggestion for the application of CIF in clinic. Method Commercial finite element method(FEM) Program ANSYS was applied to set up the Finite Element Models of orthopedic CIF and bone tissue to analyze and evaluate the biomechanical performances of the Ni Ti shape memory alloy CIF. Results There is an interaction force between embracing force of CIF and resistant force of bone tissue during the orthopedic clinical treatment. The embracing force along two semi-circular arms of CIF is increasing from the open position and reached the maximum value at the open symmetry position where the deformation of the bone occurre. Conclusion It is the key to choose the force loading position during the practical treatment, as the concentration force is the main force when there is an interactive force between the bone and the CIF.
    11  Evaluation of in vitro cytotoxicity and drug release property on pharmaceutical dressing
    HUANG Shu-jie GUAN Jing LI Zhi-hong ZHANG XI-zheng WU Ji-min
    2010, 25(1):32-35. DOI: 10.3871/j.1004-7220.2010.01.35.
    [Abstract](9310) [HTML](0) [PDF 480.67 K](4987)
    Abstract:
    Objective To evaluate the cellular toxic and release of pharmaceutical dressing. Methods Following the State standard GB/T14233.2-2005, the L929 cellular morphology was observed by inverted microscopy after 72h and proliferation of the cells was examined using mitochondrial function (MTT) assay. Relative growth rate (RGR) was calculated and cytotoxicity grade was evaluated. With PBS7.4 as dissolution media, and (32±0.5)℃ as dissolution temperature, the release rate was determined with UV method with the determination wavelength of 288nm and the dissolved liquid in1/6, 1/2, 1, 3, 16, 24, 36 and48h. Results The average cell RGR of the pharmaceutical dressing was 91.25% and reached 1 grade. L929 cellular morphology was normal. Pharmaceutical dressing release accord to Higuchi equation,and the simulated equation is Mt/M∞=0.3271t0.239. Conclusion Biologic compatibility of the pharmaceutical dressing is good, and the release of levofloxacin from the pharmaceutical dressing is sustained in vitro.
    12  Continuous measurement of arterial blood pressure based on pulse wave signal and vessel elastic chamber model
    GUO Wei LIU Guang-da JIAO Yang YANG Yu
    2012, 27(1):84-89. DOI: 10.3871/j.1004-7220.2012.1.89.
    [Abstract](5459) [HTML](0) [PDF 751.77 K](4983)
    Abstract:
    Objective An arterial blood pressure fitting method, based on pulse wave signal and vessel elastic chamber model, was researched and implemented to meet the requirement of continuous blood pressure (BP) measurement in health care. Methods Photoplethysmography (PPG) signal, electrocardiograph (ECG) signal and BP data of the subjects were collected by a self developed wearable physiological monitoring system. In accordance with the temporal relation between ECG and PPG signals, the equation of regression analysis on systolic BP value and pulse wave transient time (PWTT) was deduced, and the diastolic BP measurement was achieved by coefficients analysis on PPG wave and parameter calculation on blood vessel single elastic chamber model. Results The experiment results showed that the mean difference and the standard deviation of the method were (0.51±0.74) kPa[(384±5.54) mmHg], reaching the standard (0.665±1.064) kPa[(5±8) mmHg] proposed by Association for the Advancement of Medical Instrumentation (AAMI). Conclusions Human blood pressure can be estimated by the pulse wave signal and elastic chamber model, which provides a new method for the continuous blood pressure measurement.
    13  JCS-based method on coordinate transformation of attachment points between muscle and bone
    TANG Gang JI Wen-ting LI Yuan-chao WANG Cheng-tao
    2010, 25(1):40-44. DOI: 10.3871/j.1004-7220.2010.01.44.
    [Abstract](7124) [HTML](0) [PDF 480.96 K](4945)
    Abstract:
    Objective In order to avoid potential injuries imposed to human body, it can be feasible to use the musculoskeletal models which can be reconstructed from the cadaver color cryosection (CCC) images, computerized tomography (CT) images, magnetic resonance (MR) images or other images to analyze the dynamic properties of muscles in vivo during human movement. Methods We reconstruct the lower limb musculoskeletal model and define the uniform joint coordinate system (JCS) on the model and the subject. The coordinate transformation of the muscle attachment points both on the model and the subject is described in detail. Results The length and the moment arm of the biceps femoris (short head) during knee flexion are calculated and analyzed. Conclusion This method plays an important role in improving the kinematics and dynamic simulation and the muscle force estimation.
    14  Biomechanical effects of different traction modes on lumbar spine
    XIANG Pin DU Cheng-fei ZHAO Mei-ya TIAN Shan FAN Yu-bo WANG Li-Zhen
    2014, 29(5):399-404. DOI: 10.3871/j.1004-7220.2014.05.404.
    [Abstract](3123) [HTML](0) [PDF 1.90 M](4749)
    Abstract:
    Objective To study biomechanical effects of the lumbar spine under different traction conditions by using three-dimensional (3D) finite element method. Methods The CT images of lumbar segment L1-5 were input to the Mimics 10.01 for developing 3D geometrical model of L1-5. Then the mesh model of L1-5 was obtained using Geomagic Studio 12.0 and Hypermesh 11.0. The finite element simulation of the lumbar spine under different traction conditions was made by using Abaqus. Results Head-down titling angle was related to the nucleus pulposus stress. When the head-down tilting angle was smaller than 10°, the nucleus pulposus stress regularly changed with the swing cycle; while the head-down tilting angle exceeded 10°, the stress was decreased. In the swing mode, the annulus inner ring stress was increased to promote intervertebral retraction. Conclusions The traction mode helps to relieve the lumbar pain with the swing helping to coordinate the traction effect in each direction, which can better sort out and relieve the rear facet joint disorders. In addition, patients should be careful to select the appropriate traction force in the treatment to achieve good therapeutic effect.
    15  Segmentation of heart valves in DS CT image based on Contourlet transform
    MA Li-dan YANG Xin SONG Wei QIU Jun-wei SUN Kun
    2009, 24(6):408-413. DOI: 10.3871/j.1004-7220.2009.6.413.
    [Abstract](4622) [HTML](0) [PDF 737.80 K](4632)
    Abstract:
    Objective Children’s heart valves by DS CT images were enhanced and segmented in order to reconstruct 3D construction of heart valves and do motion analysis according to this model. Methods Adaptive seed-filling algorithm is proposed in this paper to segment region of interest of heart based on DS CT images. Contourlet transform is used to enhance and segment heart valve based on the part-segmented image. Results With these methods, DS CT images were successfully processed and segmented in Matlab7.0 and clear images of mitral valves were got. Conclusion The adaptive seed-filling algorithm proposed in this paper and Contourlet transform are very useful for segmentation in different situation. The conclusion in this paper provides useful reference for doctors to do research on the motion of mitral valves and plan on surgical operation of mitral valves.
    16  Investigation on Mechanical Property of the Compound Scaffold of Sol-Gel Bioactive Glass/Collegan
    ZHANG Juan-juan MENG Yong-chun CHEN Xiao-feng LI Yu-li LUO Xiaogang LIN Cai
    2010, 25(1):16-20. DOI: 10.3871/j.1004-7220.2010.01.20.
    [Abstract](7696) [HTML](0) [PDF 703.81 K](4575)
    Abstract:
    Objective To investigate the mechanical prosperity and degradation rate of the scaffolds by compounding collagen and the nano sol-gel derived bioactive glass were studied in this paper,and that would provide the theoretical basis for the further application of collagen based scaffold. Method The scaffold by compounding collagen and the nano sol-gel derived bioactive glass (58S) were prepared using the freeze-drying techniques with the bioactive glass as phase addition. To affect the aggregation state of the collagen fibers with adjusting the supplementation of bioactive glass, then the microstructures of the compound scaffold would be different. At last, the compound scaffolds with different mechanical properties were prepared. Results (1) As the aggregation state of the collagen fibers changed, the scaffold with the coarser collagen fibers with the diameters 400-600nm approximately is prepared. The coarser collagen fibers would play an important role in improving the mechanical property and slowing down the degradation rate of the collagen based scaffolds. (2) The interactions between bioactive glass and collagen are studied by FTIR and Raman technologies. When the quality of content of collagen in the compound scaffold is lower than 20%, the secondary structure of collagen is damaged severely. Conclusions The composite scaffold with the mass ratio of collagen to bioactive glass to 40:60 has the best performance in mechanical property and degradation, which would be helpful for further applications
    17  Propagation of nonlinear pressure wave in artery vessels
    ZHANG Shan-yuan ZHANG Tao YANG Fang
    2010, 25(1):63-67. DOI: 10.3871/j.1004-7220.2010.01.67.
    [Abstract](6642) [HTML](0) [PDF 535.26 K](4524)
    Abstract:
    Objective The mechanical model of nonlinear blood flow in large blood vessels is developed and the propagation of nonlinear pressure wave is studied. Methods Taking the effect of large deformation, nonlinear equation of motion is established in the current configuration in terms of the constitutive equations proposed by demiray for soft biological tissues. Results Employing the reductive perturbation method the KdV equation is derived from the nonlinear partial equations governing the motion of coupled system. Conclusion It is shown from this that the system admits an accurate periodic wave solution or solitary wave solution under certain conditions.
    18  Diagnosis value of urodynamics in patients with benign prostate hypertrophy
    ZHOU Zhi-hua Wang Ya-wei Ying Liang Luo Ming Qiu Fang
    2010, 25(1):74-76. DOI: 10.3871/j.1004-7220.2010.01.76.
    [Abstract](6280) [HTML](0) [PDF 344.72 K](4451)
    Abstract:
    Objective To evaluate the diagnosis value of urodynamics in patients with benign prostate hypertrophy(BPH).Methods With urodynamic device,the full set of urodynamic exam was administrated in 427 patients with BPH,and the externalsphincter urethral myogram was monitored simultaneously in pressure-flow studies(PFS).The umdynamic finding such as Qmax 、Pdet-Qmax、Popen、DS(descending slope) and post-voiding residual(PVR)were recorded,as well as the situation of bladder detrusor constraction and bladder compliance and urethral sphincter coordination. The bladder outflow obstruction was diagnosed by A-G nomogram,P-Q plot and DS.The IPSS score and prostate volume were also acquired. Results The diagnostic rate of BOO is 81.5%,among them concomitantly detrusor muscle impair in 117 cases(27.4%), decreased bladder compliance in 162 case (37.9%),urethral sphincter dyssynergia in 148 cases(34.7%),and unstable bladder in l64 cases (38.4%). The increase degree of BOO show an increasing tendency with urodynamic findings such as Qmax ,Pdet-Qmax,Popen,DS and IPSS score and prostatic volume respectively,however a decreasing tendency with Qmax and bladder compliance. Conclusions The urodynamic exam plays an important role in diagnosis of BOO.There is a positive relation among degree of BOO with urodynamic finding such as Pdet-Qmax,Popen,DS and IPSS score and prostatic volume,however,negative relation with Qmax and bladder compliance respectively.
    19  Study on the three-dimensional chitosan-decellularised-derma scaffolds for bone tissue engineering
    ZHANG Yan LI Rui-xin ZHANG Xi-zheng GUO Yong
    2010, 25(1):11-15. DOI: 10.3871/j.1004-7220.2010.01.15.
    [Abstract](5826) [HTML](0) [PDF 669.96 K](4329)
    Abstract:
    Objective: To observe the adhesion of MC3T3-El osteoblastic progenitor cells to the three-dimensional chitosan-decellularised-derma scaffolds, and evaluate the cytocompatibility of the scaffolds. Methods: The three-dimensional chitosan-decellularised-derma scaffolds were prepared by the freeze-drying method, the porosity, density and water absorption of which were measured. The microscopic morphology of the composite scaffolds was analyzed by the scanning electron microscopy (SEM). The MC3T3-E1 cells cultivated in vitro were seeded onto the composite scaffolds, and then co-cultured for 2, 3, 4 and 5 hours. At each time point, three specimens from each matrix were taken to determine the cell-adhesion rate, in order to ascertain the best time of the cell-adhesion. The cells were seeded onto the composite scaffolds, and then co-cultured for 1, 3, 5, 7, 9, 11 and 13 days. The MC3T3-E1 cells inside were evaluated with MTS test. The cell morphology was observed by the histological staining. The compression tests were performed using a Universal Testing Machine, at room temperature, as compared with no-cell-scaffolds.Results: The three-dimensional chitosan-decellularised-derma scaffolds had high interval porosity with the porosity (92.8%), the density (0.09796g/ml) and the water absorption (2169±100)%. The cytocompatibility test showed that the seeded MC3T3-E1 cells could adhere to the scaffolds and proliferate.Conclusion:The three-dimensional chitosan-decellularised-derma scaffolds had high interval porosity with the well-distributed diameter. The MC3T3-E1 cells were easy to adhere the scaffolds and proliferate which showed that the scaffolds had a good cytocompatibility.
    20  Biomechanical evaluation of an injectable calcium phosphate cement incorporating DHS for osteoporotic intertrochanteric fracture :An in vitro study
    YU Ren ZHANG Yu-fa NI Cheng LU Chun-de CHENG Jun-qiu FAN Hong-song
    2010, 25(1):51-55. DOI: 10.3871/j.1004-7220.2010.1.55.
    [Abstract](5972) [HTML](0) [PDF 597.23 K](4223)
    Abstract:
    Objective Objective To evaluate the biomechanical effects of using a new injectable calcium phosphate cement to consolidate the fixation of osteoporotic intertrochanteric fracture. Method Five matched pairs of human cadaver femora were used to produce the model of intertrochanteric fracture. All fractures were fixed with dynamic hip screws(DHS),and divided into two groups. In the CPC consolidation group of each pair, CPC was used to grout the hip screw and to fill the posteromedial defect. All femora were subjected to biomechanical test. Result Under the loading of 500 N, in the CPC consolidation group, the mean axial stiffness was (691.93±18.90) N/mm and the horizontal shear stiffness was (5553.84±27.47) N/mm. The mean lateral and medial strength was 5.15±0.35 MPa and (4.13±0.24) MPa. The torsion stiffness was 0.41 and the ultimate loading was (3580±286)N. In the control group, the mean axial stiffness was (453.45±19.75) N/mm, the horizontal shear stiffness was (3848.87±22.63) N/mm, the mean lateral and medial strength was (3.12±0.37) MPa and (1.80±0.21) MPa, and, the torsion stiffness was 0.35 and the ultimate loading was (2512±189)N. Consolidation fixation with CPC increased each of the biomechanical efficiency(P<0.05). Conclusion CPC consolidation of osteoprotic femoral head and the medial defect of intertrochanteric fracture could significantly improve the overall stability and decrease the rate of postoperative complication.

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