An extended and reasonable stress boundary condition at an osteon exte- rior wall is presented to solve the model proposed by Remond and Naili. The obtained pressure and fluid velocity solutions are used to investigat...An extended and reasonable stress boundary condition at an osteon exte- rior wall is presented to solve the model proposed by Remond and Naili. The obtained pressure and fluid velocity solutions are used to investigate the osteonal poroelastic behaviors. The following results are obtained. （i） Both the fluid pressure and the velocity amplitudes are proportional to the strain amplitude and the loading frequency. （ii） In the physiological loading state, the key role governing the poroelastic behaviors of the osteon is the strain rate. （iii） At the osteon scale, the pressure is strongly affected by the permeability variations, whereas the fluid velocity is not.展开更多
In the paper, two theoretical poroelastic osteon models are presented to compare their poroelastic behaviors, one is the hollow osteon model （Haversian fluid is neglected） and the other is the osteon model with Have...In the paper, two theoretical poroelastic osteon models are presented to compare their poroelastic behaviors, one is the hollow osteon model （Haversian fluid is neglected） and the other is the osteon model with Haversian fluid con- sidered. They both have the same two types of imperme- able exterior boundary conditions, one is elastic restraint and the other is displacement constrained, which can be used for analyzing other experiments performed on similarly shaped poroelastic specimens. The obtained analytical pressure and velocity solutions demonstrate the effects of the loading fac- tors and the material parameters, which may have a signifi- cant stimulus to the mechanotransduction of bone remodel- ing signals. Model comparisons indicate： （1） The Haversian fluid can enhance the whole osteonal fluid pressure and ve- locity fields. （2） In the hollow model, the key loading fac- tor governing the poroelastic behavior of the osteon is strain rate, while in the model with Haversian fluid considered, the strain rate governs only the velocity. （3） The pressure ampli- tude is proportional to the loading frequency in the hollow model, while in the model with Haversian fluid considered, the loading frequency has little effect on the pressure ampli- tude.展开更多
In order to well understand the mechanism of the mechanotransduction in bone, we propose a new model of transverse iso- tropic and poroelastic osteon cylinder considering Haversian fluid pressure. The analytical pore ...In order to well understand the mechanism of the mechanotransduction in bone, we propose a new model of transverse iso- tropic and poroelastic osteon cylinder considering Haversian fluid pressure. The analytical pore pressure and velocity solutions are obtained to examine the fluid transport behavior and pressure distribution in a loaded osteon on two different exterior sur- face cases. Case I is stress free and fully permeable and case I1 is impermeable. The following are the results obtained. （i） The Haversian fluid may not be ignored because it can enlarge the whole osteonal fluid pressure field, and it bears the external loads together with the solid skeleton. （ii） The increase of both axial strain amplitude and frequency can result in the increase of fluid pressure and velocity amplitudes, while in case II, the frequency has little effect on the fluid pressure amplitude. （iii） Under the same loading conditions, the pressure amplitude in case II is larger than that in case I, while the velocity amplitude is smaller than that in case I. This model permits the linking of the external loads to the osteonal fluid pressure and velocity, which may be a stimulus to the mechanotransduction of bone remodeling signals.展开更多
Background:Human bone analysis is a useful tool in assessing and identifying skeletal remains.To make this easier,newer and modified approaches have often being documented.Aims and Objectives:The aim of this study is ...Background:Human bone analysis is a useful tool in assessing and identifying skeletal remains.To make this easier,newer and modified approaches have often being documented.Aims and Objectives:The aim of this study is to analyze the histomorphometric features of various bone segments and its relevance in forensic case diagnosis.Materials and Methods:The human bones used were that of cadaveric bone samples harvested from three adult male Nigerians.The proximal,midshaft and distal segments of the femur,tibia,and humerus were utilized for the study.The bone sections were subjected to processing using Frost’s rapid manual preparation of ground sections techniques.Histomorphometric evaluation studied the number of primary osteons,secondary osteons,and osteon fragments,as well as the Haversian canal diameter(HCD).Results:The primary osteons,secondary osteons,osteon fragments,and HCD in each of the segments of the long bones show that the F values are less than the F critical for an alpha level of 0.05.This shows that there is no statistically significant(P>0.05)variation in the histomorphometric pattern for the various segments of the bones studied.Again differences in the haversian canal diameter of the various segments of the long bones shows statistically significant variation(P<0.05)among the long bones investigated.Conclusion:These findings have laid to rest the challenges with using the only available bone fragment for forensic case investigation as no notable variations exist across various segments.展开更多
基金Project supported by the National Natural Science Foundation of China (No. 11032008)
文摘An extended and reasonable stress boundary condition at an osteon exte- rior wall is presented to solve the model proposed by Remond and Naili. The obtained pressure and fluid velocity solutions are used to investigate the osteonal poroelastic behaviors. The following results are obtained. （i） Both the fluid pressure and the velocity amplitudes are proportional to the strain amplitude and the loading frequency. （ii） In the physiological loading state, the key role governing the poroelastic behaviors of the osteon is the strain rate. （iii） At the osteon scale, the pressure is strongly affected by the permeability variations, whereas the fluid velocity is not.
基金supported by the National Natural Science Foundation of China(11032008 and 11302143)
文摘In the paper, two theoretical poroelastic osteon models are presented to compare their poroelastic behaviors, one is the hollow osteon model （Haversian fluid is neglected） and the other is the osteon model with Haversian fluid con- sidered. They both have the same two types of imperme- able exterior boundary conditions, one is elastic restraint and the other is displacement constrained, which can be used for analyzing other experiments performed on similarly shaped poroelastic specimens. The obtained analytical pressure and velocity solutions demonstrate the effects of the loading fac- tors and the material parameters, which may have a signifi- cant stimulus to the mechanotransduction of bone remodel- ing signals. Model comparisons indicate： （1） The Haversian fluid can enhance the whole osteonal fluid pressure and ve- locity fields. （2） In the hollow model, the key loading fac- tor governing the poroelastic behavior of the osteon is strain rate, while in the model with Haversian fluid considered, the strain rate governs only the velocity. （3） The pressure ampli- tude is proportional to the loading frequency in the hollow model, while in the model with Haversian fluid considered, the loading frequency has little effect on the pressure ampli- tude.
基金supported by the National Natural Science Foundation ofChina (Grant No. 11032008)the Shanxi Province Outstanding Innovation Project for Graduates (Grant No. 20113041)
文摘In order to well understand the mechanism of the mechanotransduction in bone, we propose a new model of transverse iso- tropic and poroelastic osteon cylinder considering Haversian fluid pressure. The analytical pore pressure and velocity solutions are obtained to examine the fluid transport behavior and pressure distribution in a loaded osteon on two different exterior sur- face cases. Case I is stress free and fully permeable and case I1 is impermeable. The following are the results obtained. （i） The Haversian fluid may not be ignored because it can enlarge the whole osteonal fluid pressure field, and it bears the external loads together with the solid skeleton. （ii） The increase of both axial strain amplitude and frequency can result in the increase of fluid pressure and velocity amplitudes, while in case II, the frequency has little effect on the fluid pressure amplitude. （iii） Under the same loading conditions, the pressure amplitude in case II is larger than that in case I, while the velocity amplitude is smaller than that in case I. This model permits the linking of the external loads to the osteonal fluid pressure and velocity, which may be a stimulus to the mechanotransduction of bone remodeling signals.
文摘Background:Human bone analysis is a useful tool in assessing and identifying skeletal remains.To make this easier,newer and modified approaches have often being documented.Aims and Objectives:The aim of this study is to analyze the histomorphometric features of various bone segments and its relevance in forensic case diagnosis.Materials and Methods:The human bones used were that of cadaveric bone samples harvested from three adult male Nigerians.The proximal,midshaft and distal segments of the femur,tibia,and humerus were utilized for the study.The bone sections were subjected to processing using Frost’s rapid manual preparation of ground sections techniques.Histomorphometric evaluation studied the number of primary osteons,secondary osteons,and osteon fragments,as well as the Haversian canal diameter(HCD).Results:The primary osteons,secondary osteons,osteon fragments,and HCD in each of the segments of the long bones show that the F values are less than the F critical for an alpha level of 0.05.This shows that there is no statistically significant(P>0.05)variation in the histomorphometric pattern for the various segments of the bones studied.Again differences in the haversian canal diameter of the various segments of the long bones shows statistically significant variation(P<0.05)among the long bones investigated.Conclusion:These findings have laid to rest the challenges with using the only available bone fragment for forensic case investigation as no notable variations exist across various segments.
