Ma Baoshun, Smith Bradford J, Bates Jason H T
University of Vermont College of Medicine, Burlington, VT 05405, United States.
University of Vermont College of Medicine, Burlington, VT 05405, United States.
Respir Physiol Neurobiol. 2015 Jun;211:22-8. doi: 10.1016/j.resp.2015.03.004. Epub 2015 Mar 23.
We have recently shown that if the lung parenchyma is modeled in 2 dimensions as a network of springs arranged in a pattern of repeating hexagonal cells, the distortional forces around a contracting airway propagate much further from the airway wall than classic continuum theory predicts. In the present study we tested the hypothesis that this occurs because of the negligible shear modulus of a hexagonal spring network. We simulated the narrowing of an airway embedded in a hexagonal network of elastic alveolar walls when the hexagonal cells of the network offered some resistance to a change in shape. We found that as the forces resisting shape change approach about 10% of the forces resisting length change of an individual spring the range of distortional force propagation in the spring network fell of rapidly as in an elastic continuum. We repeated these investigations in a 3-dimensional spring network composed of space-filling polyhedral cells and found similar results. This suggests that force propagation away from a point of local parenchymal distortion also falls off rapidly in real lung tissue.
我们最近发现，如果将肺实质在二维上建模为以重复六边形细胞模式排列的弹簧网络，收缩气道周围的变形力从气道壁传播的距离比经典连续介质理论预测的要远得多。在本研究中，我们检验了这样一个假设，即出现这种情况是因为六边形弹簧网络的剪切模量可忽略不计。当网络的六边形细胞对形状变化提供一定阻力时，我们模拟了嵌入弹性肺泡壁六边形网络中的气道变窄情况。我们发现，当抵抗形状变化的力接近单个弹簧抵抗长度变化的力的约10%时，弹簧网络中变形力传播的范围会像在弹性连续介质中一样迅速下降。我们在由空间填充多面体细胞组成的三维弹簧网络中重复了这些研究，得到了类似的结果。这表明在真实肺组织中，远离局部实质变形点的力传播也会迅速下降。
