Objective： To study the stress distribution of the femoral hip prosthesis after the hip joint replacement. Methods： After the hip joint replacement, when the fenmr and prosthesis are considered as concentric cylinde...Objective： To study the stress distribution of the femoral hip prosthesis after the hip joint replacement. Methods： After the hip joint replacement, when the fenmr and prosthesis are considered as concentric cylinders with perfectly banded interface, a relatively perfect theoretical model of simulating the interracial stress transfer is established. Results： The maximum interfaeial shear stress oeeured at Z=O. At the cross-section of the femoral neck, interfacial shear stress decreased exponentially with the increases of the Z. Shear stress became very small at Z〉0. 1 m, which meant that the shear stress at the far end of the femoral hip prosthesis was very small. In order to avoid the stress concentration and femoral hip prosthesis sinking, interracial stress must remain constant and balanced with the pressure load at Z=O. The radius of the femoral hip prosthesis changed with interfacial shear stress. The maximum value of the radius occured at Z=O, then it decreased at m. Specially, a=18.2 mm at Z=10 ram, a=5.36 mm at Z=98 ram, these are ideal radius. Conclusion： A theoretical model of simulating the interfacial stress is established when the femur and prosthesis are considered as concentric cylinders. The distributions of the interfacial shear and radial stresses with the axial positions are obtained. A theoretical reference for the design of the prosthesis is provided.展开更多
Adequate energy storage is essential for sustaining healthy life. Lipid droplet （LD） is the subcellular organelle that stores energy in the form of neutral lipids and releases fatty acids under energy deficient cond...Adequate energy storage is essential for sustaining healthy life. Lipid droplet （LD） is the subcellular organelle that stores energy in the form of neutral lipids and releases fatty acids under energy deficient conditions. Energy storage capacity of LDs is primarily dependent on the sizes of LDs. Enlargement and growth of LDs is controlled by two molecular pathways： neutral lipid synthesis and atypical LD fusion. Shrinkage of LDs is mediated by the degradation of neutral lipids under energy demanding conditions and is controlled by neutral cytosolic lipases and lysosomal acidic lipases. In this review, we summarize recent progress regarding the regulatory pathways and molecular mechanisms that control the sizes and the energy storage capacity of LDs.展开更多
Modulation of the morphology of nanostructures is often a rewarding but challenging task. We have employed the seeded growth method and induced kinetic control to synthesize Bi2Se3 nanoplates with modifiable morpholog...Modulation of the morphology of nanostructures is often a rewarding but challenging task. We have employed the seeded growth method and induced kinetic control to synthesize Bi2Se3 nanoplates with modifiable morphology. By manipulating the rate at which precursor solutions were injected into seeds solution with syringe pumps, two distinctive growth modes could be realized. With a fast injection, the thickness of Bi2Se3 nanoplates slightly increased from N7.5 nm （seeds） to -9.5 nm while the edge length grew up from ~160 nm （seeds） to N12 ~tm, after 6 successive rounds of seeded growth. With a slow injection, the thickness and edge length increased simultaneously to -35 nm and -6 b^m after 6 rounds of growth, respectively. These two modes could be viewed as a competition between atomic deposition and surface migration. The products showed interesting, thickness-dependent Raman properties. In addition, NIR transparent, highly conductive and flexible Bi2Se3 thin films with different thicknesses were constructed by the assembly of the as-synthesized Bi2Se3 nanoplates. This approach based on seeded growth and kinetic control can significantly promote the development of versatile nanostructures with diverse morphology.展开更多
文摘Objective： To study the stress distribution of the femoral hip prosthesis after the hip joint replacement. Methods： After the hip joint replacement, when the fenmr and prosthesis are considered as concentric cylinders with perfectly banded interface, a relatively perfect theoretical model of simulating the interracial stress transfer is established. Results： The maximum interfaeial shear stress oeeured at Z=O. At the cross-section of the femoral neck, interfacial shear stress decreased exponentially with the increases of the Z. Shear stress became very small at Z〉0. 1 m, which meant that the shear stress at the far end of the femoral hip prosthesis was very small. In order to avoid the stress concentration and femoral hip prosthesis sinking, interracial stress must remain constant and balanced with the pressure load at Z=O. The radius of the femoral hip prosthesis changed with interfacial shear stress. The maximum value of the radius occured at Z=O, then it decreased at m. Specially, a=18.2 mm at Z=10 ram, a=5.36 mm at Z=98 ram, these are ideal radius. Conclusion： A theoretical model of simulating the interfacial stress is established when the femur and prosthesis are considered as concentric cylinders. The distributions of the interfacial shear and radial stresses with the axial positions are obtained. A theoretical reference for the design of the prosthesis is provided.
基金supported by the National Natural Science Foundation of China(31420040,31321003 to Peng Li,31501089 to Jinhai Yu)the National Basic Research Program(2013CB530602 to Peng Li)the China Postdoctoral Science Foundation(2015M581079 to Jinhai Yu)
文摘Adequate energy storage is essential for sustaining healthy life. Lipid droplet （LD） is the subcellular organelle that stores energy in the form of neutral lipids and releases fatty acids under energy deficient conditions. Energy storage capacity of LDs is primarily dependent on the sizes of LDs. Enlargement and growth of LDs is controlled by two molecular pathways： neutral lipid synthesis and atypical LD fusion. Shrinkage of LDs is mediated by the degradation of neutral lipids under energy demanding conditions and is controlled by neutral cytosolic lipases and lysosomal acidic lipases. In this review, we summarize recent progress regarding the regulatory pathways and molecular mechanisms that control the sizes and the energy storage capacity of LDs.
文摘Modulation of the morphology of nanostructures is often a rewarding but challenging task. We have employed the seeded growth method and induced kinetic control to synthesize Bi2Se3 nanoplates with modifiable morphology. By manipulating the rate at which precursor solutions were injected into seeds solution with syringe pumps, two distinctive growth modes could be realized. With a fast injection, the thickness of Bi2Se3 nanoplates slightly increased from N7.5 nm （seeds） to -9.5 nm while the edge length grew up from ~160 nm （seeds） to N12 ~tm, after 6 successive rounds of seeded growth. With a slow injection, the thickness and edge length increased simultaneously to -35 nm and -6 b^m after 6 rounds of growth, respectively. These two modes could be viewed as a competition between atomic deposition and surface migration. The products showed interesting, thickness-dependent Raman properties. In addition, NIR transparent, highly conductive and flexible Bi2Se3 thin films with different thicknesses were constructed by the assembly of the as-synthesized Bi2Se3 nanoplates. This approach based on seeded growth and kinetic control can significantly promote the development of versatile nanostructures with diverse morphology.
