Objective To elucidate the influence of osteoporosis on the fracture healing in ovariectomized rat. Methods 24 females 8-month-old SD rats were divided randomly into two groups.12 were sham-operated(Sham)and 12 were b...Objective To elucidate the influence of osteoporosis on the fracture healing in ovariectomized rat. Methods 24 females 8-month-old SD rats were divided randomly into two groups.12 were sham-operated(Sham)and 12 were bilaterally ovariectomized(OVX) 3 months later.The femoral fracture model were made in both groups,the healing process was observed by transmission electron microscopy(TEM) on d3,d7,d14,d21,d28,and d42 after making fracture in control groups(Sham) and the osteoporosis group(OVX). Results According to the TEM findings,the types of fracture healing cells,their ultrastructure changes and functional states were almost identical in both groups till d21 after making fracture.In OVX group,the calcified cartilage was not resorbed and replaced by new woven bone,a lot of necrosis chondrocytes were found being embedded in a calcified chondroid matrix on d28;after this period,osteoclastic bone resorption become severe gra- dually accompanied by osteocytic osteolysis during d28 to d42 of fracture healing. Conclusion Osteoporosis greatly affect the fracture healing in the later period of healing proess.It demonstrated as endochondral bone formation delayed and increased osteoclastic bone resorption which was made even more severed by osteocytic osteolysis during the period of bone callus remodelling.展开更多
By means of HAAKE RS105L cone and plate rheometer the concentrated solution, including viscous flow activation energy, non-Newtonian index, structural viscosity index and relaxation time of the PMIA solution were stud...By means of HAAKE RS105L cone and plate rheometer the concentrated solution, including viscous flow activation energy, non-Newtonian index, structural viscosity index and relaxation time of the PMIA solution were studied. The effect of concentration and temperature of the solution and molecular weight of the polymer on its non-Newtonian behavior was investigated. The results showed that PMIA concentrated solution prepared via low temperature condensation was of non-Newtonian fluid. With the decrease of temperature, increase of solution concentration and PMIA molecular weight, the deviation of the solution from Newtonian behavior decreased. The molecular weight of the polymer and the concentration of the solution affected the non- Newtonian behavior mete intensively.展开更多
Structural relaxation and glass transition in binary hard-spherical particle mixtures have been reported to exhibit unusual features depending on the size disparity and composition. However, the mechanism by which the...Structural relaxation and glass transition in binary hard-spherical particle mixtures have been reported to exhibit unusual features depending on the size disparity and composition. However, the mechanism by which the mixing effects lead to these features and whether these features are universal for particles with anisotropic geometries remains unclear. Here, we employ event-driven molecular dynamics simulation to investigate the dynamical and structural properties of binary two-dimensional hard-ellipse mixtures. We find that the relaxation dynamics for translational degrees of freedom exhibit equivalent trends as those observed in binary hard-spherical mixtures. However, the glass transition densities for translational and rotational degrees of freedom present different dependencies on size disparity and composition. Furthermore,we propose a mechanism based on structural properties that explain the observed mixing effects and decoupling behavior between translational and rotational motions in binary hard-ellipse systems.展开更多
文摘Objective To elucidate the influence of osteoporosis on the fracture healing in ovariectomized rat. Methods 24 females 8-month-old SD rats were divided randomly into two groups.12 were sham-operated(Sham)and 12 were bilaterally ovariectomized(OVX) 3 months later.The femoral fracture model were made in both groups,the healing process was observed by transmission electron microscopy(TEM) on d3,d7,d14,d21,d28,and d42 after making fracture in control groups(Sham) and the osteoporosis group(OVX). Results According to the TEM findings,the types of fracture healing cells,their ultrastructure changes and functional states were almost identical in both groups till d21 after making fracture.In OVX group,the calcified cartilage was not resorbed and replaced by new woven bone,a lot of necrosis chondrocytes were found being embedded in a calcified chondroid matrix on d28;after this period,osteoclastic bone resorption become severe gra- dually accompanied by osteocytic osteolysis during d28 to d42 of fracture healing. Conclusion Osteoporosis greatly affect the fracture healing in the later period of healing proess.It demonstrated as endochondral bone formation delayed and increased osteoclastic bone resorption which was made even more severed by osteocytic osteolysis during the period of bone callus remodelling.
文摘By means of HAAKE RS105L cone and plate rheometer the concentrated solution, including viscous flow activation energy, non-Newtonian index, structural viscosity index and relaxation time of the PMIA solution were studied. The effect of concentration and temperature of the solution and molecular weight of the polymer on its non-Newtonian behavior was investigated. The results showed that PMIA concentrated solution prepared via low temperature condensation was of non-Newtonian fluid. With the decrease of temperature, increase of solution concentration and PMIA molecular weight, the deviation of the solution from Newtonian behavior decreased. The molecular weight of the polymer and the concentration of the solution affected the non- Newtonian behavior mete intensively.
基金supported by the National Natural Science Foundation of China(21474109,21674055)the International Partnership Program of Chinese Academy of Sciences(121522KYSB20160015)the Youth Innovation Promotion Association of Chinese Academy of Sciences(2016204)
文摘Structural relaxation and glass transition in binary hard-spherical particle mixtures have been reported to exhibit unusual features depending on the size disparity and composition. However, the mechanism by which the mixing effects lead to these features and whether these features are universal for particles with anisotropic geometries remains unclear. Here, we employ event-driven molecular dynamics simulation to investigate the dynamical and structural properties of binary two-dimensional hard-ellipse mixtures. We find that the relaxation dynamics for translational degrees of freedom exhibit equivalent trends as those observed in binary hard-spherical mixtures. However, the glass transition densities for translational and rotational degrees of freedom present different dependencies on size disparity and composition. Furthermore,we propose a mechanism based on structural properties that explain the observed mixing effects and decoupling behavior between translational and rotational motions in binary hard-ellipse systems.
