Objective To comparatively investigate the inorganic composition and crystallographic properties of cortical and cancellous bone via thermal treatment under 700 ℃. Methods Thermogravimetric measurement, infrared spec...Objective To comparatively investigate the inorganic composition and crystallographic properties of cortical and cancellous bone via thermal treatment under 700 ℃. Methods Thermogravimetric measurement, infrared spectrometer, X-ray diffraction, chemical analysis and X-ray photo-electron spectrometer were used to test the physical and chemical properties of cortical and cancellous bone at room temperature 250 ℃, 450 ℃, and 650 ℃, respectively. Results The process of heat treatment induced an extension in the a-lattice parameter and changes of the c-lattice parameter, and an increase in the crystallinity reflecting lattice rearrangement after release of lattice carbonate and possible lattice water. The mineral content in cortical and cancellous bone was 73.2wt% and 71.5wt%, respectively. For cortical bone, the weight loss was 6.7% at the temperature from 60 ℃ to 250℃, 17.4% from 250 ℃ to 450 ℃, and 2.7% from 450 ℃ to 700 ℃. While the weight loss for the cancellous bone was 5.8%, 19.9%, and 2.8 % at each temperature range, the Ca/P ratio of cortical bone was 1.69 which is higher than the 1.67 of stoichiometric HA due to the B-type CO32- substitution in apatite lattice. The CaJP ratio of cancellous bone was lower than 1.67, suggesting the presence of more calcium deficient apatite. Conclusion The collagen fibers of cortical bone were arrayed more orderly than those of cancellous bone, while their mineralized fibers ollkded similar. The minerals in both cortical and cancellous bone are composed of poorly crystallized nano-size apatite crystals with lattice carbonate and possible lattice water. The process of heat treatment induces a change of the lattice parameter, resulting in lattice rearrangement after the release of lattice carbonate and lattice water and causing an increase in crystal size and crystallinity. This finding is helpful for future biomaterial design, preparation and application.展开更多
Human bone may be damaged by impact in the cases of traffic accidents and ship impact. The impact responses of cancellous bone were analyzed based on the two-phase media theory. A direct analytical method is introduce...Human bone may be damaged by impact in the cases of traffic accidents and ship impact. The impact responses of cancellous bone were analyzed based on the two-phase media theory. A direct analytical method is introduced for solving this type of problems. First, flow function and potential function were introduced to decouple the controlling equations. Then direction solving method was used to obtain the solution. The solution is determined by the parameters of a (related with wave speed) and b (related with damping), as well as the boundary conditions. These two parameters a and b determine the propagation speed of the responses along the bone and the attenuation rate. It is shown that the responses: deformation, stress and pressure of the corpus medullae caused by loading, propagate toward the other end when the impact is acted on one end of the bone. The responses are discontinuous during propagate. The discontinuous surface moves with a constant speed. The responses at the cross section increase gradually from the bottom to the top because of the distribution of the loading at the boundary. The solutions can be used as the basis for certification of numerical simulation as well as the design of impact prevention of bone.展开更多
Tissue-engineered bone scaffolds provide temporary mechanical support for bone tissue growth. Mechanical stimuli are transferred to seeded cells through the scaffold structure to promote cell proliferation and differe...Tissue-engineered bone scaffolds provide temporary mechanical support for bone tissue growth. Mechanical stimuli are transferred to seeded cells through the scaffold structure to promote cell proliferation and differentiation. This paper presents a numerical investigation specifically on bone and cartilage tissue differentiation with the aim to provide a theoretical basis for scaffold design and bone defect repair in clinics. In this study, the scaffold structures were established on the basis of cancellous bone microarchitectures. For finite element simulations, inlet velocity and compressive strain were applied under in vitro culture conditions. The influences of this scaffold mor- phology and macro-level culture conditions on micro-mechanical stimuli at scaffold surfaces were investigated. Correlations between the microarchitectural parameters and the mechanical parameters, as well as the cell differentiation parameters were analyzed. Highly het- erogeneous stress distributions were observed on the scaffolds with irregular morphology. Cell differentiation on the scaffold was more sensitive to the inlet velocity than the axial strain. In addition, cartilage differentiation on the scaffolds with structures comprising more plate-like trabeculae was more pronounced than on those with more rod-like trabeculae. This paper is helpful to gain more insight into the mechanical environments under in vitro culture conditions that approximate the in vivo mechanical environments of Bone Marrow Stromal Ceils （BMSCs）.展开更多
In the application of cancellous bone ultrasound diagnosis based on backscattering method, it is of great importance to estimate fast and accurately whether the valid backscattering signal exists in the received signa...In the application of cancellous bone ultrasound diagnosis based on backscattering method, it is of great importance to estimate fast and accurately whether the valid backscattering signal exists in the received signal. We propose a fast estimation method based on spectrum entropy method. With 984 records of adult calcaneus clinical data, we estimate the validity of the backscatter signal using this method. The results of the proposed method and the results of experience-base judgement were compared and analyzed. And two key parameters, the signal range length and the segment number of the spectrum entropy, were analyzed. The results show when the signal range length is 13 I^s and the segment number is 15 20, this method can get the best result （accuracy〉95%, sensitivity〉99%, specificity〉87%）, while taking little calculation time （1.5 ms）. Therefore, this spectrum entropy method can satisfy the accuracy and real-time requirements in the ultrasonic estimation for cancellous bone.展开更多
Cortical bone consists of osteons embedded in interstitial bone tissue and there is a thin amorphous interface, named cement line, between osteon and interstitial bone. Due to fatigue and cyclic loading, the pullout o...Cortical bone consists of osteons embedded in interstitial bone tissue and there is a thin amorphous interface, named cement line, between osteon and interstitial bone. Due to fatigue and cyclic loading, the pullout or debonding phenomenon often occurs in osteonal and interstitial tissue bone. The study aims to construct a fiber-reinforced composite material debonding model for cortical bone, in which the bonding condition along the osteon, cement line and interstitial tissue bone are assumed to be imperfect. In the study, we used the complex variable method to obtain series representations for stress fields in the osteon, cement line and the interstitial tissue bone with a radial crack. The effects of material properties of osteon and cement line, crack position, and varying degrees of debonding on the fracture behavior were investigated by computing the stress intensity factor （SIF） in the vicinity of the microcrack tips. The investigation results indicated that the cement line was important for controlling the fracture toughening mechanisms and that the level of imperfect bonding among osteon, cement line and interstitial tissue bone had a pronounced effect on the crack behavior and should not be ignored.展开更多
Abstract Objective To determine the concentrations of lead （Pb） and cadmium （Cd） in three kinds of materials （cartilage, cortical bone, and cancellous bone） of the femur head obtained from patients in the proces...Abstract Objective To determine the concentrations of lead （Pb） and cadmium （Cd） in three kinds of materials （cartilage, cortical bone, and cancellous bone） of the femur head obtained from patients in the process of operation. Methods Concentrations of Pb and Cd were determined in selected parts of the femur head of 30 patients after total hip arthroplasty, using ICP-AES （atomic absorption spectrophotometry）. Results Pb contained the highest concentration in cortical bone, while Cd did so in cancellous bone. There were statistically significant differences in the concentrations of both elements between the cartilage and cortical bone, and also differences in the concentration of Pb between the cartilage and cancellous bone. There were no significant differences in the concentrations of Pb or Cd between cortical and cancellous bone. Conclusion Comparative studies on toxic metals should take into account both analogous bones and their fragments, as even if they come from the same kind of bones （e.g. femur head）, clear differences exist in concentrations of heavy metals related to the sampling site and type of tissue （cartilage, cortical bone, and cancellous bone）.展开更多
基金supported by China 973 Fund(No.2007CB936102) the National Natural Science Foundation of China (No.50972096)
文摘Objective To comparatively investigate the inorganic composition and crystallographic properties of cortical and cancellous bone via thermal treatment under 700 ℃. Methods Thermogravimetric measurement, infrared spectrometer, X-ray diffraction, chemical analysis and X-ray photo-electron spectrometer were used to test the physical and chemical properties of cortical and cancellous bone at room temperature 250 ℃, 450 ℃, and 650 ℃, respectively. Results The process of heat treatment induced an extension in the a-lattice parameter and changes of the c-lattice parameter, and an increase in the crystallinity reflecting lattice rearrangement after release of lattice carbonate and possible lattice water. The mineral content in cortical and cancellous bone was 73.2wt% and 71.5wt%, respectively. For cortical bone, the weight loss was 6.7% at the temperature from 60 ℃ to 250℃, 17.4% from 250 ℃ to 450 ℃, and 2.7% from 450 ℃ to 700 ℃. While the weight loss for the cancellous bone was 5.8%, 19.9%, and 2.8 % at each temperature range, the Ca/P ratio of cortical bone was 1.69 which is higher than the 1.67 of stoichiometric HA due to the B-type CO32- substitution in apatite lattice. The CaJP ratio of cancellous bone was lower than 1.67, suggesting the presence of more calcium deficient apatite. Conclusion The collagen fibers of cortical bone were arrayed more orderly than those of cancellous bone, while their mineralized fibers ollkded similar. The minerals in both cortical and cancellous bone are composed of poorly crystallized nano-size apatite crystals with lattice carbonate and possible lattice water. The process of heat treatment induces a change of the lattice parameter, resulting in lattice rearrangement after the release of lattice carbonate and lattice water and causing an increase in crystal size and crystallinity. This finding is helpful for future biomaterial design, preparation and application.
文摘Human bone may be damaged by impact in the cases of traffic accidents and ship impact. The impact responses of cancellous bone were analyzed based on the two-phase media theory. A direct analytical method is introduced for solving this type of problems. First, flow function and potential function were introduced to decouple the controlling equations. Then direction solving method was used to obtain the solution. The solution is determined by the parameters of a (related with wave speed) and b (related with damping), as well as the boundary conditions. These two parameters a and b determine the propagation speed of the responses along the bone and the attenuation rate. It is shown that the responses: deformation, stress and pressure of the corpus medullae caused by loading, propagate toward the other end when the impact is acted on one end of the bone. The responses are discontinuous during propagate. The discontinuous surface moves with a constant speed. The responses at the cross section increase gradually from the bottom to the top because of the distribution of the loading at the boundary. The solutions can be used as the basis for certification of numerical simulation as well as the design of impact prevention of bone.
基金This work is supported by the National Natural Science Foundation of China （Nos. 81471753, 11432016 and 11322223）, the project from Science and Technology Department of Jilin Province （20160101297JC）, the project from Department of Education Science and Technology of Jilin Province （JJKH20180560KJ） and the grant from China Scholarship Council.
文摘Tissue-engineered bone scaffolds provide temporary mechanical support for bone tissue growth. Mechanical stimuli are transferred to seeded cells through the scaffold structure to promote cell proliferation and differentiation. This paper presents a numerical investigation specifically on bone and cartilage tissue differentiation with the aim to provide a theoretical basis for scaffold design and bone defect repair in clinics. In this study, the scaffold structures were established on the basis of cancellous bone microarchitectures. For finite element simulations, inlet velocity and compressive strain were applied under in vitro culture conditions. The influences of this scaffold mor- phology and macro-level culture conditions on micro-mechanical stimuli at scaffold surfaces were investigated. Correlations between the microarchitectural parameters and the mechanical parameters, as well as the cell differentiation parameters were analyzed. Highly het- erogeneous stress distributions were observed on the scaffolds with irregular morphology. Cell differentiation on the scaffold was more sensitive to the inlet velocity than the axial strain. In addition, cartilage differentiation on the scaffolds with structures comprising more plate-like trabeculae was more pronounced than on those with more rod-like trabeculae. This paper is helpful to gain more insight into the mechanical environments under in vitro culture conditions that approximate the in vivo mechanical environments of Bone Marrow Stromal Ceils （BMSCs）.
基金supported by the National Natural Science Foundation of China(11327405,11525416,11604054,11504057)
文摘In the application of cancellous bone ultrasound diagnosis based on backscattering method, it is of great importance to estimate fast and accurately whether the valid backscattering signal exists in the received signal. We propose a fast estimation method based on spectrum entropy method. With 984 records of adult calcaneus clinical data, we estimate the validity of the backscatter signal using this method. The results of the proposed method and the results of experience-base judgement were compared and analyzed. And two key parameters, the signal range length and the segment number of the spectrum entropy, were analyzed. The results show when the signal range length is 13 I^s and the segment number is 15 20, this method can get the best result （accuracy〉95%, sensitivity〉99%, specificity〉87%）, while taking little calculation time （1.5 ms）. Therefore, this spectrum entropy method can satisfy the accuracy and real-time requirements in the ultrasonic estimation for cancellous bone.
文摘Cortical bone consists of osteons embedded in interstitial bone tissue and there is a thin amorphous interface, named cement line, between osteon and interstitial bone. Due to fatigue and cyclic loading, the pullout or debonding phenomenon often occurs in osteonal and interstitial tissue bone. The study aims to construct a fiber-reinforced composite material debonding model for cortical bone, in which the bonding condition along the osteon, cement line and interstitial tissue bone are assumed to be imperfect. In the study, we used the complex variable method to obtain series representations for stress fields in the osteon, cement line and the interstitial tissue bone with a radial crack. The effects of material properties of osteon and cement line, crack position, and varying degrees of debonding on the fracture behavior were investigated by computing the stress intensity factor （SIF） in the vicinity of the microcrack tips. The investigation results indicated that the cement line was important for controlling the fracture toughening mechanisms and that the level of imperfect bonding among osteon, cement line and interstitial tissue bone had a pronounced effect on the crack behavior and should not be ignored.
基金financed as research project no.NN404507738 by the Polish Ministry of Education from the resources for years 2010-2011
文摘Abstract Objective To determine the concentrations of lead （Pb） and cadmium （Cd） in three kinds of materials （cartilage, cortical bone, and cancellous bone） of the femur head obtained from patients in the process of operation. Methods Concentrations of Pb and Cd were determined in selected parts of the femur head of 30 patients after total hip arthroplasty, using ICP-AES （atomic absorption spectrophotometry）. Results Pb contained the highest concentration in cortical bone, while Cd did so in cancellous bone. There were statistically significant differences in the concentrations of both elements between the cartilage and cortical bone, and also differences in the concentration of Pb between the cartilage and cancellous bone. There were no significant differences in the concentrations of Pb or Cd between cortical and cancellous bone. Conclusion Comparative studies on toxic metals should take into account both analogous bones and their fragments, as even if they come from the same kind of bones （e.g. femur head）, clear differences exist in concentrations of heavy metals related to the sampling site and type of tissue （cartilage, cortical bone, and cancellous bone）.
