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Copyright of Chinese Journal of Tissue Engineering Research / Zhongguo Zuzhi Gongcheng Yanjiu is the property of Chinese Journal of Tissue Engineering Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Tissue Engineering Research / Zhongguo Zuzhi Gongcheng Yanjiu is the property of Chinese Journal of Tissue Engineering Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND: Cancellous bone, as an important part of bone, is a kind of porous, inhomogeneous, anisotropic and viscoelastic structure, which plays a critical role in load transmission and energy absorption. Therefore, research on its mechanical properties is of great significance. OBJECTIVE: To investigate the compressive properties of cancellous bone at different stress rates and its creep behaviors at different stress levels. METHODS: The fresh cancellous bone from pig femur was used as the material, and subjected to different stress until the compressive strain of sample was up to 5%. The constant compressive stress levels were loaded on the surface of cancellous bone for 7 200 s to observe its creep behaviors. RESULTS AND CONCLUSION: (1) In the uniaxial compression test, the stress values and Young's modulus increased with the stress rate increasing under the same strain value. (2) The stress-strain curves of cancellous bone were different at different loading rates, indicating that the mechanical properties of cancellous bone depend on the loading rate. (3) In the creep test, the creep strain increased with the increase of stress level, but the creep compliance decreased with the increase of stress level. (4) These results suggest that the stress rate and stress level have significant influence on compressive properties of cancellous bone, which provide reference for avoiding cancellous bone injury. [ABSTRACT FROM AUTHOR]

BACKGROUND: It is of great significance to study the resilience of articular cartilage for human daily routine and their match quality. OBJECTIVE: To analyze the micromechanical properties of articular cartilage resilience under different loads and at time points. METHODS: The swine cartilage samples coated with tracers were compressed using the MTF-100 tensile machine, and the cartilage compression and resilience were recorded by CCD. Images were processed using digital image correlation technology. RESULTS AND CONCLUSION: During resilience, the strain value on the superficial surface of the cartilage was decreased most, successively followed by the middle layer and the deep layer, while the time of a decrease from 20%, 10% and 6% to 3% was similar. The longer the resilience time was, the more slowly the strain changed in different layers of the cartilage, but the ultimate strain was less than 1%. On the same layer under different compressive stress, the larger load caused faster strain change firstly, and then the smaller load brought about faster strain change. The effect of different continuous compressive time on the same layer of cartilage was similar with the load. These results showed that 90% resilience of the articular cartilage occurred within the first 15 minutes. The mechanical resilience of different layers of the articular cartilage has a close relationship with the loading and the loading time, and both compressive time and loading do harm to the resilience of articular cartilage. Besides, the cartilage will rebound to the state before compression. [ABSTRACT FROM AUTHOR]