2001, 16(1):1-5. DOI: 10.3871/j.1004-7220.2001.01.5.
Abstract:The co-culture of endothelial cells (ECs) with smooth muscle cells (SMCs) is an important method to study the biological characteristics of ECs and SMCs in vitro. but there are many difference of morphology and functions between in vitro and in vivo. It may because of no considering of the effects of blood flow shear stress. Therefore, we established the flow chamber system for the PET membrane co-culture model. through which we can obtain 0-40dyn/cm2 steady laminar flow shear stress. Using this system. the morphology of ECs co-cultured with SMCs were studied. The ECs alligned its long axis along the dire,direction of flow under 40dysn/cm2 for 24hours. The establishment of this flow chamber system provided a method to study the morphology and functions of ECs co-cultured with SMCs.
2001, 16(1):6-9. DOI: 10.3871/j.1004-7220.2001.01.9.
Abstract:There exist residual stress in rat trachea. When a no-load trachea ring is cut radially, it opens into a sector, which is the zero-stress state of the trachea. Results in this paper show that for the no-load ring of rat trachea, the opening angle obtained for cartilaginous cut differs from that for muscular cut, i.e. the opening angle. for cartilaginous cut is significantly larger than that for muscular cut. And the opening angle obtained from muscular cut is basically identical along longitu- dinal location and that from cartilaginous cut tend to increase with the longitudinal distance x/L increasing. The results are helpful for studying adapting growth of the trachea in response to certain mechanical environment.
2001, 16(1):10-14. DOI: 10.3871/j.1004-7220.2001.01.14.
Abstract:Objective:To investigate the biomechanical properties of deep fascia of leg in response to the Tension-Stress Principle during limb lengthening. Methods:Limb lengthening animal model was established in New Zealand white rabbits using a unilateral external fixator applied with four pins to the medial surface of the tibia and monofocal proximal diaphyseal osteotomy with closed multiple drill holes and osteoclasis between the second and the third pins.Seven days after operation,distraction was initiated at a rate of 1mm/day and 2mm/day in two steps, and proceeded until increases of 10% and 20% in the initial length of tibia had been achieved.The deep fascia samples of 30x10mm were clamped to the Instron 1122 tensile testdevice at room temperature with the constant tensile rate of 5mm/min.After 5 load-download tensile tests,the samples were elongated until rupture.And the load-displacement curves were automatically generated by the apparatus. Results:The normal deep fascia showed typical load-displacement rules of collagenous tissues.And each experimental fascia kept the characteristics.The curves of fascias at the distraction rate of 1mm/day were closer to the curves of normal fascias.For the normal fascias,the ultimate tension strength was avarage 2.69N,and the strain at rupture was avarage 14.11%.And the ultimate tension strength of the fascias after lengthening increased. Conclusion:These results prove that the Tension-Stress during limb lengthening. has great effect upon foe biomechanical properties of deep fascia.The curves of fascias at a rate of 1mm/day and increase of 20% were the closest to the curves of normal deep fascias.
2001, 16(1):15-17. DOI: 10.3871/j.1004-7220.2001.01.17.
Abstract:PFM has the advantages of real color and anti-milled, widely used in restoration of teeth destroyed, teeth incomplete and teeth beauty. However, due to the issue of brittleness of ceramics and its manufacturing technology. the happing lost ceramics. crack inside and interface separate often occur clinically .In this regard, it not only delay the restoration, but also greatly add the expense of restoration. Hence, an inspection method is required to develop. in order to judge whether there is flaw on the PFM teeth cover or inside both before and after restoration. This study will adopt Scanning Acoustic Microscope and X-Ray Microscope Inspection to conduct the Nondestructive testing for PFM restoration. The results showed that the above two methods are both feasible on flaw inspection, Especially, the combination of two methods could effectively inspect the flaw's depth and size on PFM cover or inside, this will provide wide clinical application in the future.
2001, 16(1):18-22. DOI: 10.3871/j.1004-7220.2001.01.22.
Abstract:Objective:To evaluate the efficacy of BSYJF on raising the quality of cacellous bone of vertebrate in osteoposrotic rat model induced by ovariectomy and to inquiry into the mechanism on improving biomechanical propelties of cancellous bone. Method:Forty 12-month-old female Wistar rats were divided randomizedly into four groups:Sham control group,Ovx contral group,BSYJF group(Ovx+BSYJF) and BML group(Ovx+BML). After sacrifice, biomechanical parameters and other parameters of No.2 lulmbar vertebrate were determined. Results:The macroscopic geometry structure(height and volume) in Ovx control group, BSYJF group and BML group were not altered siguificantgroup were reduced by 11% (p<0.05) and 6% (p >0.05 ),respectively vs Sham control group. In comparison with those Of Ovx control group,the BMD and the BCD in BSYJF group were increased by 3% (p<0.05) and 8% (p> 0.05),and the BMD and the BCD in BML group were increased by 9% (p<0.05) and 12% (p>0.05).The mechanical parameters in Ovx control group were all decreased significantly (p<0.05),respectively vs Sham control group.Especially,in elastic phase,the mechanical parameter in BSYJF group were increased significantly (p <0.05 ),vs Ovx control group;but those in BML group were not increased significantly (p >0. 05 ),vs Ovx control group. In plastic phase,the mechanical parameters were increasedsignificantly,respectively vs Ovx control group.Conclusion:BSYJF can not only raise the quality of cancellous bone of vertebrate in the rat model induced by ovariectomy,but also have superiority to BML in improving the cancellous bone mechanical property in elastic phase.
2001, 16(1):23-26. DOI: 10.3871/j.1004-7220.2001.01.26.
Abstract:Objective:to seek suitable condition for calcining bovine bone and to provide a kind of good heterologous organic material for repairing bone defect. Methods: bovine bone slices (40mm×5mm×2.5mm) were calcined at various temperature and lasted for various period of time. Then the following properties of the bovine calcined bone slices were tested: porosity rate, hydrophilism, density, bending strength, mineral composition and heat analysis. Results: the major mineral composition of bovine calcined bone was HA of low crystallization. the suitable condition for calcining were the tempreture of 450℃ and lasted for about 32 hours, when the porosity rate of bovine calcined bone was 50.64% and its bending strength was 17.57Mpa. Otherwise, the physical property of bovine calcined bone would be decreased and some immunity would be remained. Conclusion: the suitablecalsined condition was at the temperature of 450℃ for about 32 hours. the major mineral composition of this heterologous organic bone was HA. it retained original frame of bovine bone and some mechanical strength. it has potential capability of repairing bone defect of conductivity.
2001, 16(1):27-32. DOI: 10.3871/j.1004-7220.2001.01.32.
Abstract:In this study, the analytical expressions of pressure and wall shear stress in local vessel expansion region were deduced through solving the linear blood now equations. with the assumption of the development process mode of the local vessel expansion with time, the progresses of the pressure and wall shear stress in local vessel region were discussed. Results show that in the local vessel expansion section, the pressure is slightly larger than that in the uniform vascular section, and that the shear stress decreases significantly, which will have some effects on vessel tissues.
2001, 16(1):33-39. DOI: 10.3871/j.1004-7220.2001.01.39.
Abstract:Purpose: To explore the method and probability for directly measuring the stress in lumbar facet joint and disc under dynamic loading, to afford the experimental base for further investigation of intra-articular stress changing regularity under different motion conditions. Methods: Using micro pressure-sensitive crystal sensor and long lumbar segment, to collect, transform and analysis the signal under six status. To analysis and test the features of signal and experimental instrument. Results: We get complex and non-periodic instant signal. The characteristic of whole instrument is only collecting dynamic signal. high sensitivity, large responsive frequency range. high stability and high repetition. Conclusion: This is a kind of new and practical biomechanical research method. It more directly and really express the intra-articular stress change.
2001, 16(1):40-43. DOI: 10.3871/j.1004-7220.2001.01.43.
Abstract:To provide theoretical basis for clinic bone lengthening. Methods: 20 immature New Zealand white rabbits were used in this part of the study. A configuration type distractor and force transducers was assembled on each side of distal epiphyseal cartilage of femur for application of mechanical tensinn force. Half animals made circumferential periosteal division in the proximal epiphysis. The measurement of the bone,X-ray film and KS-400 Image Analysis System were used to study the morphology and cellular proliferation of the epiphysial cartilage after 4 weeks of distraction. Result: The low tensile stress increase in length of the distracted femur and increase in thickness of the epiphyseal carting. Cell proliferation in the physis occurs in the proliferative and hypertrophic zones. No statistical difference were found in both groups which had had circumferential periosteal division and had not. Conclusion: The low tensil stress had stimulating effects on the proliferative activity of the epiphyseal cartilage. Tension force combined with ciroumferential periosteal division did not approach significant enhanced growth effects.
2001, 16(1):44-47. DOI: 10.3871/j.1004-7220.2001.1.47.
Abstract:Objective:To provide a theoryetical guide for the clinical treatment, the changes of the hemodynamics during the process of the atherosclerosis spots and thrombosis were investigated. Methods: The vascular model were simulated by the ANSYS V5.4 software, and the vessel cavity were reduced progressively just as that of the artery in the atherosclarosis and thrombosis, the blood flow of the models in those conditions were analyses by the finite element method. The blood flow states in different viscositees were also observed by the method. Results: The blood flow in the normal vessels were laminar flow, the velocities were different in every stratum, the velocities were the fastest in the center and slow down towards the vessel wall. In the field where the vessel were narrowed, the dominant now were high speed laminar flow, and the speed were accelerated with the reducing of the vessels diameter. The blood flow became silted up in both side of the narrow field. When the viscocities come down, the high speed laminar flow were moved towards aistant heart side and the basis field changed. Conclution: From the study, it was suggested that through continuously ectatic treatment to the narrowed vessels, the treatment effect may be improved. It's necessary to study the meaning of the blood viscosity in the treatment of the disease.
2001, 16(1):48-53. DOI: 10.3871/j.1004-7220.2001.01.53.
Abstract:Objective:To investegate the biomechanical effects of curing the dislocation of the hip by pelvis osteotomy. and provide a theoretical basis for clinical application. Method: Measure the compression stress. shear stress. iliac stress as well as down displacement of femoral head and acetabulum contact stress under different acetabulum exponents by applying experimental stress analysis on four full pelvis-hip-femora cadaver samples. Results: Show, under different acetabulum exponents, if the testing exponent is lower than 30°. there is no big difference between measured stress on femora and standard values (P>0.05), while if the exponent is higher than 30°, the measured stress increase fast, the difference between measured and standard values approached 15%, which fulfils the operation demands. The displacement of femora head behaves according similar rule and the contact stress concentration on hip has also been improved. Conclusion: Curing the dislocation of the hip by pelvis osteotomy not only suits biomechanical principle, but also it is a safe and secure shelf opration. it has certain clinical application.
2001, 16(1):54-56. DOI: 10.3871/j.1004-7220.2001.1.56.
Abstract:Objective:To investigate the curative effects of optimized form of Duangudan on fracture healing. Method: 64 cases of rapine distal radial fracture models were randomized into 4 groups, blank control group (normal fracture healing without treatment) group of conventional form of Duangudan, group of emplastrum form prepared from conventional extractum, group of emplastrum form prepared from optimized extractum. Meanwhile, eight cases with intact radii were sacrificed from normal control. They were sacrificed at 2nd and 4th week in batches. All involved radii were harvested for biomechanical observation (three-point bending test). Results: At the end of 2nd week, in order of curative effect, the groups were ranked as follows, group of emplastrum form prepared from optimized extractum, goup of previous form of Duangudan, an blank control group. At the end of 4th week, the rank remained all the same as that at the end of 2nd week. There was significant difference in biomechanical test between the emplastrum form prepared from optimized extractum and blank control at both ends of 2nd and 4th week. Conclusion:The emplastrum form prepared from optimized extractum was superior to the conventional form in enhancing fracture healing.
2001, 16(1):57-62. DOI: 10.3871/j.1004-7220.2001.1.62.
Abstract:Objective:To study the therapy of abdominal cavity lukewarm water filling on the effect of biomechanical properties, such as tensile strength of rat rectal healing area after low rectal cutting-anastomosis, and to analyse further the constitution equation and viscoelasticity properties of rat rectum, in order to provide scientific basis for clinical therapy. Methods: There were 32 SD rats of the clean grade. At first performed the low rectal cuttinganastomosis, and then divided into control groupA of sinple cutting-anastomosis without filling and group B of abdominal cavity lukewarm water filling. Biomechanical experiments were done 5 days and 15 days after operation. Results: The tensile strength, elasticity modulus of increasing quantity and viscoelasticity of group B were significantly better than control group A, (P<0.05). Conclusion: By using the therapy of abdominal cavity lukewarm water filling, the biomechanical properties of rectal tissue after low anastomosis of rectal cancer was not only without any notable adverse effect, but also helpful to the improvement of rectal tissue biomechanical properties.
2001, 16(1):63-65. DOI: 10.3871/j.1004-7220.2001.1.65.
Abstract:Scalp Acupuncture treatment is a clinically effective acupuncture method, and previous researches about it's therapeutic mechanics were all centered on anatomic analysis. This study has revealed the therapeutic mechanics of Flying Needle Manuver of Scalp Acupuncture through analysis on its unique biomechanics combined with physiology and pathology. Flying Needle Manuver can produces piezoelectric effect,thus it induces extensive biological and clinical therapeutic effect.