Objective： To investigate the efficacy of the locking internal fixator （LIF）, which includes the locking compression plate （LCP） and the less invasive stable system （LISS）, in the proximal and distal tibial fra...Objective： To investigate the efficacy of the locking internal fixator （LIF）, which includes the locking compression plate （LCP） and the less invasive stable system （LISS）, in the proximal and distal tibial fractures. Methods： We did a retrospective study on a total of 98 patients with either proximal or distal tibial fractures from January 2003 to January 2007, who had received the opera- tion with LIF by the minimally invasive plate osteosynthe- sis （MIPO） technique. The data consisted of 43 proximal tibial fractures （type AO41 C3） and 55 distal tibial fractures （type AO43C3）. Results： No complications were observed in all patients after operation. The mean healing time was 8.4 months （range 5-14 months）. Only two cases of delayed union oc- curred at postoperative 10 months. No infections were re- ported after the definitive surgery even in the cases of open fractures. All patients reached a full range of motion at post- operative 6 to 9 months and regained the normal functions of knee and ankle joints. Conclusion： Using LIF in MIPO technique is a reliable approach towards the proximal and distal tibial fractures that are not suitable for intramedullary nailing.展开更多
By introducing the coupling flow expressions of main fracture-matrix, secondary fracture-matrix and main fracture-secondary fracture into the traditional main fracture material balance equation, the “main fracture-se...By introducing the coupling flow expressions of main fracture-matrix, secondary fracture-matrix and main fracture-secondary fracture into the traditional main fracture material balance equation, the “main fracture-secondary fracture-matrix” leak-off coupling flow model is established. The pressure-dependent fracture width equation and the wellbore injection volume equation are coupled to solve the pressure-rate continuity problem. The simulation and calculation of the bottomhole pressure drop and fracture network closure after the pump stopping in slickwater volumetric fracturing treatment are realized. The research results show that the log-log curve of pump-stopping bottomhole pressure drop derivative presents five characteristic slope segments, reflecting four dominant stages, i.e. inter-fracture crossflow, fracture network leak-off, fracture network closure and residual leak-off, after pump shutdown. At the initial time of pump shutdown for volumetric fracturing treatment of horizontal well, the crossflow between main and secondary fractures is obvious, and then the leak-off becomes dominant. The leak-off of main and secondary fractures shows a non-uniform decreasing trend. Specifically, the leak-off of main fractures is slow, while that of secondary fractures is fast;the fracture network as a whole presents the leak-off law of fast first, then slow, until close to zero. The influence of fracture network conductivity on the shape of pressure decline curve is relatively weaker than that of fracture network size. The fracture network conductivity is positively correlated with leak-off volume and fracture closure. The secondary fracture size is positively correlated with leakoff volume and closure of the secondary fracture, but negatively correlated with closure of the main fracture. Field data validation proves that the proposed model and simulation results can effectively reflect the closure characteristics of the fracture network, and the interpretation results are reliable and can reflect the non-uniform展开更多
A flat annular crack in a piezoelectric layer subjected to electroelastic loadings is investigated under electrically impermeable boundary condition on the crack surface. Using Hankel transform technique, the mixed bo...A flat annular crack in a piezoelectric layer subjected to electroelastic loadings is investigated under electrically impermeable boundary condition on the crack surface. Using Hankel transform technique, the mixed boundary value problem is reduced to a system of singular integral equations. With the aid of Gauss-Chebyshev integration technique, the integral equations are further reduced to a system of algebraic equations. The field intensity factor and energy release rate are determined. NumericM results reveal the effects of electric loadings and crack configuration on crack propagation and growth. The results seem useful for design of the piezoelectric structures and devices of high performance.展开更多
In this paper, woven fabrics of glass fiber/carbon fiber intra-hybrid in plain structure were used to fabricate fiber reinforced plastic (FRP) composite by hand lay-up method. The investigation on tensile property was...In this paper, woven fabrics of glass fiber/carbon fiber intra-hybrid in plain structure were used to fabricate fiber reinforced plastic (FRP) composite by hand lay-up method. The investigation on tensile property was carried out on specimens in 7 orientations including 0°/5°/15°/75°/85°/90° in previous works. With the specimen parameters and experimental data, FEM model was built by the software of Marc. By combining the experimental results and finite element analysis, the modulus was simulated and calculated at the first stage. Then interfacial stress of the 0 degree and 90 degree was also calculated. By the initial fracture stress data from experiment as well as the simulation value of interfacial strength of 0 and 90 degree, the initial fracture stress of the off-axial specimens wascalculated and predicted. The result shows that the interfacial strength of the glass fiber bundle is higher than that of the carbon fiber bundle in transverse direction. By using the interfacial strength and according to the Von Mises yielding criterion, the initial fracture stress was predicted, which can be a contribution to the design or predict of the material properties.展开更多
Nonunion in tibial plateau fractures is very rare. Limited literature is available on Pubmed search on intraarticular tibial nonunion. Most of the cases reported have been following failed surgical treatment and none ...Nonunion in tibial plateau fractures is very rare. Limited literature is available on Pubmed search on intraarticular tibial nonunion. Most of the cases reported have been following failed surgical treatment and none was neglected fractures. Three patients of isolated and neglected medial fibial plateau nonunion with almost similar demo- graphic profile are reported in this paper. All the three pa- tients were managed by minimally invasive compressionfixation using lag screws supplemented with limb realign- ment procedure of high tibial osteotomy. We discussed the injury mechanism, management and rehabilitation in such cases and reviewed the available literature regarding such a presentation.展开更多
Metabolic bone disease after kidney transplantation has a complex pathophysiology and heterogeneous histology. Pre-existing renal osteodystrophy may not resolve completely, but continue or evolve into a dif-ferent ost...Metabolic bone disease after kidney transplantation has a complex pathophysiology and heterogeneous histology. Pre-existing renal osteodystrophy may not resolve completely, but continue or evolve into a dif-ferent osteodystrophy. Rapid bone loss immediately after transplant can persist, at a lower rate, for years to come. These greatly increase the risk of bone fracture and vertebral collapse. Each patient may have multiple risk factors of bone loss, such as steroids usage, hypo-gonadism, persistent hyperparathyroidism （HPT）, poor allograft function, metabolic acidosis, hypophosphate-mia, vitamin D defciency, aging, immobility and chronic disease. Clinical management requires a comprehen-sive approach to address the underlying and ongoing disease processes. Successful prevention of bone loss has been shown with vitamin D, bisphosphonates, cal-citonin as well as treatment of hypogonadism and HPT. Novel approach to restore the normal bone remodeling and improve the bone quality may be needed in order to effectively decrease bone fracture rate in kidney transplant recipients.展开更多
文摘Objective： To investigate the efficacy of the locking internal fixator （LIF）, which includes the locking compression plate （LCP） and the less invasive stable system （LISS）, in the proximal and distal tibial fractures. Methods： We did a retrospective study on a total of 98 patients with either proximal or distal tibial fractures from January 2003 to January 2007, who had received the opera- tion with LIF by the minimally invasive plate osteosynthe- sis （MIPO） technique. The data consisted of 43 proximal tibial fractures （type AO41 C3） and 55 distal tibial fractures （type AO43C3）. Results： No complications were observed in all patients after operation. The mean healing time was 8.4 months （range 5-14 months）. Only two cases of delayed union oc- curred at postoperative 10 months. No infections were re- ported after the definitive surgery even in the cases of open fractures. All patients reached a full range of motion at post- operative 6 to 9 months and regained the normal functions of knee and ankle joints. Conclusion： Using LIF in MIPO technique is a reliable approach towards the proximal and distal tibial fractures that are not suitable for intramedullary nailing.
基金Supported by the National Natural Science Foundation of China (51974332)。
文摘By introducing the coupling flow expressions of main fracture-matrix, secondary fracture-matrix and main fracture-secondary fracture into the traditional main fracture material balance equation, the “main fracture-secondary fracture-matrix” leak-off coupling flow model is established. The pressure-dependent fracture width equation and the wellbore injection volume equation are coupled to solve the pressure-rate continuity problem. The simulation and calculation of the bottomhole pressure drop and fracture network closure after the pump stopping in slickwater volumetric fracturing treatment are realized. The research results show that the log-log curve of pump-stopping bottomhole pressure drop derivative presents five characteristic slope segments, reflecting four dominant stages, i.e. inter-fracture crossflow, fracture network leak-off, fracture network closure and residual leak-off, after pump shutdown. At the initial time of pump shutdown for volumetric fracturing treatment of horizontal well, the crossflow between main and secondary fractures is obvious, and then the leak-off becomes dominant. The leak-off of main and secondary fractures shows a non-uniform decreasing trend. Specifically, the leak-off of main fractures is slow, while that of secondary fractures is fast;the fracture network as a whole presents the leak-off law of fast first, then slow, until close to zero. The influence of fracture network conductivity on the shape of pressure decline curve is relatively weaker than that of fracture network size. The fracture network conductivity is positively correlated with leak-off volume and fracture closure. The secondary fracture size is positively correlated with leakoff volume and closure of the secondary fracture, but negatively correlated with closure of the main fracture. Field data validation proves that the proposed model and simulation results can effectively reflect the closure characteristics of the fracture network, and the interpretation results are reliable and can reflect the non-uniform
基金Project supported by the National Natural Science Foundation of China(Nos.11072160 and 11272223)the Natural Science Foundation of Hebei Province,China(E2013402077)
文摘A flat annular crack in a piezoelectric layer subjected to electroelastic loadings is investigated under electrically impermeable boundary condition on the crack surface. Using Hankel transform technique, the mixed boundary value problem is reduced to a system of singular integral equations. With the aid of Gauss-Chebyshev integration technique, the integral equations are further reduced to a system of algebraic equations. The field intensity factor and energy release rate are determined. NumericM results reveal the effects of electric loadings and crack configuration on crack propagation and growth. The results seem useful for design of the piezoelectric structures and devices of high performance.
文摘In this paper, woven fabrics of glass fiber/carbon fiber intra-hybrid in plain structure were used to fabricate fiber reinforced plastic (FRP) composite by hand lay-up method. The investigation on tensile property was carried out on specimens in 7 orientations including 0°/5°/15°/75°/85°/90° in previous works. With the specimen parameters and experimental data, FEM model was built by the software of Marc. By combining the experimental results and finite element analysis, the modulus was simulated and calculated at the first stage. Then interfacial stress of the 0 degree and 90 degree was also calculated. By the initial fracture stress data from experiment as well as the simulation value of interfacial strength of 0 and 90 degree, the initial fracture stress of the off-axial specimens wascalculated and predicted. The result shows that the interfacial strength of the glass fiber bundle is higher than that of the carbon fiber bundle in transverse direction. By using the interfacial strength and according to the Von Mises yielding criterion, the initial fracture stress was predicted, which can be a contribution to the design or predict of the material properties.
文摘Nonunion in tibial plateau fractures is very rare. Limited literature is available on Pubmed search on intraarticular tibial nonunion. Most of the cases reported have been following failed surgical treatment and none was neglected fractures. Three patients of isolated and neglected medial fibial plateau nonunion with almost similar demo- graphic profile are reported in this paper. All the three pa- tients were managed by minimally invasive compressionfixation using lag screws supplemented with limb realign- ment procedure of high tibial osteotomy. We discussed the injury mechanism, management and rehabilitation in such cases and reviewed the available literature regarding such a presentation.
文摘Metabolic bone disease after kidney transplantation has a complex pathophysiology and heterogeneous histology. Pre-existing renal osteodystrophy may not resolve completely, but continue or evolve into a dif-ferent osteodystrophy. Rapid bone loss immediately after transplant can persist, at a lower rate, for years to come. These greatly increase the risk of bone fracture and vertebral collapse. Each patient may have multiple risk factors of bone loss, such as steroids usage, hypo-gonadism, persistent hyperparathyroidism （HPT）, poor allograft function, metabolic acidosis, hypophosphate-mia, vitamin D defciency, aging, immobility and chronic disease. Clinical management requires a comprehen-sive approach to address the underlying and ongoing disease processes. Successful prevention of bone loss has been shown with vitamin D, bisphosphonates, cal-citonin as well as treatment of hypogonadism and HPT. Novel approach to restore the normal bone remodeling and improve the bone quality may be needed in order to effectively decrease bone fracture rate in kidney transplant recipients.
