Nonlinear Dynamics in Microvascular Networks

描述（由申请人提供）： 微循环一直被认为是活性生物学的结果。 控制最近的计算机模拟表明， 可以表现出非线性动力学。自发持续和阻尼振荡 也可以是稳定状态。模拟是基于良好的 确定的血液流变学特性; Fahraeus-Lindqvist效应和 血浆撇除基于体内观察的真实网络几何结构 在模拟中使用大鼠肠系膜。 本研究将为这些模型提供实验验证 预测。将灌注小微血管网络的体外复制品 在预计允许的条件下， 振荡将通过压力测量监测振荡。两 将研究树型和拱廊型网络。将使用体外方法 以避免实验期间的生物防治活性。数值 还计划进行模拟，以确定参数的影响，例如 血管直径、长度、血细胞比容、红细胞停留时间等 振荡的振幅和频率。数值研究还将 探索周期加倍和混沌波动的可能性， 问题中的参数是变化的。 预期的结果将提供一个非线性动力学模型， 需要审查生物控制机制的概念。振荡 由于非线性效应引起的流量和压力也会对质量产生影响 将计算从血液转移到周围组织。时变流是 也与血管壁的健康有关。

DESCRIPTION (provided by applicant): Temporal fluctuations in the microcirculation have long been considered the result of active biological control. Recent computer simulations indicate that the microvascular networks can exhibit nonlinear dynamics. Spontaneous sustained and damped oscillations can occur as well as steady states. The simulations are based on well established blood rheological properties; the Fahraeus-Lindqvist effect and plasma skimming. Realistic network geometries based on in vivo observations of rat mesentery are used in the simulations. The proposed research will provide experimental verification of these model predictions. In vitro replicas of small microvascular networks will be perfused with red blood cell suspensions under conditions predicted to permit oscillations. Oscillations will be monitored by pressure measurements. Both tree- and arcade type networks will be studied. In vitro methods will be used to avoid biological control activity during the experiments. Numerical simulations are also planned to determine the influence of parameters such as vessel diameters, lengths, hematocrits, red cell residence times, etc on the amplitude and frequency of the oscillations. Numerical research will also explore the possibility of period doubling and chaotic fluctuations as parameters in the problem are varied. The anticipated results will provide a nonlinear dynamic model through which the concepts of biological control mechanisms need to be viewed. Oscillating flows and pressures due to nonlinear effects will also have an impact on mass transfer calculations from blood to surrounding tissues. Time varying flows are also implicated in the health of the vessel wall.