Thermal and diffusion processes in laser-induced stress relaxation and reshaping of cartilage
Thermal and diffusion processes in laser-induced stress relaxation and reshaping of cartilage
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DOI：
10.1016/s0021-9290(97)00028-6
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发表时间：
1997-08-01
影响因子：
2.4
通讯作者：
Howdle, SM
中科院分区：
文献类型：
--
作者：
Bagratashvili, VN;Sobol, EN;Howdle, SM
用差示微量热法和傅里叶变换红外光谱研究了水的“束缚-自由”相变的热力学特征。这种相变控制着软骨的应力松弛和重塑，这是我们之前在适度激光加热下观察到的。结果表明，软骨中结合水的FTIR谱与软骨中游离水的FTIR谱不同，与纯水的FTIR谱也不同。软骨中结合水的比例约为4%。我们研究了水的释放和吸收动力学，发现它们受组织中的扩散和结合水到自由水的转化的控制。理论模型和实验数据允许计算扩散系数和水传递的活化能。后者与水的相变热相近。我们已经确定，软骨的干燥和润湿过程是可逆的(完全或部分，取决于初步干燥的温度)，并且可以用扩散问题的相同解来描述，水的扩散系数相同。文中还讨论了水分在软骨组织中的扩散机制。(C)1997年，爱思唯尔科学有限公司出版。
The thermodynamic characteristics of the 'bound-to-free' phase transformation of water are studied by means of differential microcalorimetry and FTIR spectroscopy. This phase transition controls the stress relaxation and reshaping of cartilage which we have observed previously under moderate laser heating. It is shown that the FTIR spectrum of bound water in cartilage differs from that of free water in cartilage, and that both show differences to the FTIR spectrum of pure water. The proportion of bound water in cartilage is found to be of the order 4%. We have examined water liberation and absorption kinetics and found them to be controlled by diffusion through the tissue and also by the bound-to-free water transformation. The theoretical modelling and experimental data allowed calculation of diffusion coefficients and the activation energy for water transfer. The latter was found to be close to the heat of phase transformation of water. We have established that the drying and wetting processes in cartilage are reversible (fully or in a part, depending on the temperature of preliminary drying) and can be described by identical solutions of the diffusion problem, with coefficients of water diffusion being the same. The mechanism of water diffusion in cartilaginous tissue is also discussed. (C) 1997 Published by Elsevier Science Ltd.