In order to obtain the value of confined water progressive intrusion height of mining fracture floor, the analysis equation was deduced based on the fracture extension theory of the fracture mechanics. Further- more, ...In order to obtain the value of confined water progressive intrusion height of mining fracture floor, the analysis equation was deduced based on the fracture extension theory of the fracture mechanics. Further- more, the influence of some parameters （e.g., advancing distance of working face, water pressure, initial fracture length and its angle） on confined water progressive intrusion height were analyzed. The results indicate that tension-shearing fracture of floor is extended more easily than compression-shearing frac- ture under the same conditions. When floor fracture dip angle is less than 90% tension-shearing extension occurs more easily on the left edge of the goaf. If fracture dip angle is larger than 90% it occurs more easily on the right edge of the goal. The longer the advancing distance of working face is, the greater initial frac- ture length goes; or the larger water pressure is, the greater possibility of tension-shearing extension occurs. The confined water progressive intrusion height reaches the maximum on the edge of the goaf. Field in situ test is consistent with the theoretical analysis result.展开更多
Bone remodeling is performed under the joint action of osteoblasts and osteoclasts. Since the effect of osteoclasts has been gradually recognized on bone and joint diseases, targeted researches toward osteoclasts have...Bone remodeling is performed under the joint action of osteoblasts and osteoclasts. Since the effect of osteoclasts has been gradually recognized on bone and joint diseases, targeted researches toward osteoclasts have become a hot research field. This article reviews the relevant medical literature concerning the possible effects of the fluid shear stress (FSS) on the osteoclastogenesis chiefly from the aspects of RANKL-RANK-OPG system, the macrophage colony-stimulating factor (M-CSF), and calcitonin receptor (CTR). On the basis of the changes of the expression of osteoclastic activities, it is suggested that FSS is a potent, important regulator of bone metabolism.展开更多
In this study, Computational Fluid Dynamics(CFD) is used to investigate and compare the impact of bioreactor parameters(such as its geometry, medium flow-rate, scaffold configuration) on the local transport phenomena ...In this study, Computational Fluid Dynamics(CFD) is used to investigate and compare the impact of bioreactor parameters(such as its geometry, medium flow-rate, scaffold configuration) on the local transport phenomena and, hence, their impact on human mesenchymal stem cell(hM SC) expansion. The geometric characteristics of the TissueFlex174;(Zyoxel Limited, Oxford, UK) microbioreactor were considered to set up a virtual bioreactor containing alginate(in both slab and bead configuration) scaffolds. The bioreactor and scaffolds were seeded with cells that were modelled as glucose consuming entities. The widely used glucose medium, Dulbecco's Modified Eagle Medium(DMEM), supplied at two inlet flow rates of 25 and 100 μl·h^(-1), was modelled as the fluid phase inside the bioreactors. The investigation, based on applying dimensional analysis to this problem, as well as on detailed three-dimensional transient CFD results, revealed that the default bioreactor design and boundary conditions led to internal and external glucose transport, as well as shear stresses, that are conducive to h MSC growth and expansion. Furthermore, results indicated that the ‘top-inout' design(as opposed to its symmetric counterpart) led to higher shear stress for the same media inlet rate(25 μl·h^(-1)), a feature that can be easily exploited to induce shear-dependent differentiation. These findings further confirm the suitability of CFD as a robust design tool.展开更多
Isolated coronal fractures of femoral condyle are rare in adults and nonunion of Hoffa fracture is reported only a few times in the literature. We analyzed six cases of nonunion of Hoffa fractures over a period of thr...Isolated coronal fractures of femoral condyle are rare in adults and nonunion of Hoffa fracture is reported only a few times in the literature. We analyzed six cases of nonunion of Hoffa fractures over a period of three years. Three patients were treated conservatively and three patients had fixation failures. Delay of presentation was 2 months to one year. Treatment protocol consisted of open reduction, excision of pseudoarthrosis, bone grafting and internal fixation along with knee arthrolysis. Union wasachieved in all patients at mean 16 weeks. The treatment of nonunion of Hoffa fractures requires careful preoperative planning and meticulous surgical technique. The literature regarding the controversies in fracture management and surgical technique are reviewed.展开更多
Objective： Talar body fractures are rare and have poor treatment outcome. The purpose of this study is to report the long term surgical treatment outcome of closed talar dome fractures.Methods： Eight closed talar bo...Objective： Talar body fractures are rare and have poor treatment outcome. The purpose of this study is to report the long term surgical treatment outcome of closed talar dome fractures.Methods： Eight closed talar body fractures, treated by open reduction and internal fixation with small fragment cancellous screws and/or Herbert screws in our level Ⅰ trauma centre were retrospectively analyzed. Preoperative and postoperative radiographs of the foot （antero-posterior, lateral and oblique views） and ankle （antero-posterior, lateral and mortise views） were obtained. The patients were followed up both radiologically and functionally （foot function index, FFI） after 3 weeks, 6 weeks, 3 months, 6 months and then annually.Results： There were five crush fractures and three shear fractures （two sagittal shear and one coronal shear）,with average follow-up of 5 years. No early complications were noticed in these patients. Late complications included osteoarthrosis of subtalar/ankle joints in six patients and osteonecrosis oftalar body in four patients. On functional assessment, mean FFI after 5 years was 104.63 points and worse outcome was noticed in crush injury and coronal shear fractures. Sagittal shear fractures had a good functional and radiological outcome.Conclusions： Late complications subsequent to surgically treated talar body fractures are inevitable, even though exact reduction and rigid fixation are achieved, thus patients are supposed to be counseled about the adverse outcome. Although crush and coronal shear fractures have poor outcome, sagittal injuries have good prognosis on long term evaluation.展开更多
基金provided by the National Natural Science Foundation of China (Nos. 51474008 and 41472235)the State Key Laboratory for Coal Resources and Safe Mining, China University of Mining &Technology (No. SKLCRSM13KFB01)+1 种基金the Scientific Research Foundation of Young Teacher of Anhui University of Science and Technology (No. QN201308)the State of College Students’ Innovation Training Project (No. 201210361006)
文摘In order to obtain the value of confined water progressive intrusion height of mining fracture floor, the analysis equation was deduced based on the fracture extension theory of the fracture mechanics. Further- more, the influence of some parameters （e.g., advancing distance of working face, water pressure, initial fracture length and its angle） on confined water progressive intrusion height were analyzed. The results indicate that tension-shearing fracture of floor is extended more easily than compression-shearing frac- ture under the same conditions. When floor fracture dip angle is less than 90% tension-shearing extension occurs more easily on the left edge of the goaf. If fracture dip angle is larger than 90% it occurs more easily on the right edge of the goal. The longer the advancing distance of working face is, the greater initial frac- ture length goes; or the larger water pressure is, the greater possibility of tension-shearing extension occurs. The confined water progressive intrusion height reaches the maximum on the edge of the goaf. Field in situ test is consistent with the theoretical analysis result.
文摘Bone remodeling is performed under the joint action of osteoblasts and osteoclasts. Since the effect of osteoclasts has been gradually recognized on bone and joint diseases, targeted researches toward osteoclasts have become a hot research field. This article reviews the relevant medical literature concerning the possible effects of the fluid shear stress (FSS) on the osteoclastogenesis chiefly from the aspects of RANKL-RANK-OPG system, the macrophage colony-stimulating factor (M-CSF), and calcitonin receptor (CTR). On the basis of the changes of the expression of osteoclastic activities, it is suggested that FSS is a potent, important regulator of bone metabolism.
基金Department of Engineering Science, University of Oxford, Scholarship
文摘In this study, Computational Fluid Dynamics(CFD) is used to investigate and compare the impact of bioreactor parameters(such as its geometry, medium flow-rate, scaffold configuration) on the local transport phenomena and, hence, their impact on human mesenchymal stem cell(hM SC) expansion. The geometric characteristics of the TissueFlex174;(Zyoxel Limited, Oxford, UK) microbioreactor were considered to set up a virtual bioreactor containing alginate(in both slab and bead configuration) scaffolds. The bioreactor and scaffolds were seeded with cells that were modelled as glucose consuming entities. The widely used glucose medium, Dulbecco's Modified Eagle Medium(DMEM), supplied at two inlet flow rates of 25 and 100 μl·h^(-1), was modelled as the fluid phase inside the bioreactors. The investigation, based on applying dimensional analysis to this problem, as well as on detailed three-dimensional transient CFD results, revealed that the default bioreactor design and boundary conditions led to internal and external glucose transport, as well as shear stresses, that are conducive to h MSC growth and expansion. Furthermore, results indicated that the ‘top-inout' design(as opposed to its symmetric counterpart) led to higher shear stress for the same media inlet rate(25 μl·h^(-1)), a feature that can be easily exploited to induce shear-dependent differentiation. These findings further confirm the suitability of CFD as a robust design tool.
文摘Isolated coronal fractures of femoral condyle are rare in adults and nonunion of Hoffa fracture is reported only a few times in the literature. We analyzed six cases of nonunion of Hoffa fractures over a period of three years. Three patients were treated conservatively and three patients had fixation failures. Delay of presentation was 2 months to one year. Treatment protocol consisted of open reduction, excision of pseudoarthrosis, bone grafting and internal fixation along with knee arthrolysis. Union wasachieved in all patients at mean 16 weeks. The treatment of nonunion of Hoffa fractures requires careful preoperative planning and meticulous surgical technique. The literature regarding the controversies in fracture management and surgical technique are reviewed.
文摘Objective： Talar body fractures are rare and have poor treatment outcome. The purpose of this study is to report the long term surgical treatment outcome of closed talar dome fractures.Methods： Eight closed talar body fractures, treated by open reduction and internal fixation with small fragment cancellous screws and/or Herbert screws in our level Ⅰ trauma centre were retrospectively analyzed. Preoperative and postoperative radiographs of the foot （antero-posterior, lateral and oblique views） and ankle （antero-posterior, lateral and mortise views） were obtained. The patients were followed up both radiologically and functionally （foot function index, FFI） after 3 weeks, 6 weeks, 3 months, 6 months and then annually.Results： There were five crush fractures and three shear fractures （two sagittal shear and one coronal shear）,with average follow-up of 5 years. No early complications were noticed in these patients. Late complications included osteoarthrosis of subtalar/ankle joints in six patients and osteonecrosis oftalar body in four patients. On functional assessment, mean FFI after 5 years was 104.63 points and worse outcome was noticed in crush injury and coronal shear fractures. Sagittal shear fractures had a good functional and radiological outcome.Conclusions： Late complications subsequent to surgically treated talar body fractures are inevitable, even though exact reduction and rigid fixation are achieved, thus patients are supposed to be counseled about the adverse outcome. Although crush and coronal shear fractures have poor outcome, sagittal injuries have good prognosis on long term evaluation.
