Nonlinear Dynamics in Microvascular Networks

描述(由申请人提供)：时间波动 长期以来，微循环一直被认为是生物活动的结果 控制力。最近的计算机模拟表明，微血管网络 可以表现出非线性动力学。自发持续和阻尼式振荡 既可以发生也可以处于稳定状态。这些模拟是基于Well 已建立的血液流变性；Fahraeus-Lindqvist效应和 等离子撇油。基于活体观测的逼真网络几何 在模拟中使用了大鼠的肠系膜。 拟议的研究将为这些模型提供实验验证 预测。小微血管网络的体外复制将被灌流 在预计允许的条件下使用红细胞悬浮液 震荡。振荡将通过压力测量进行监测。两者都有 将研究树型和拱廊型网络。将使用体外方法 以避免在试验期间进行生物防治活动。数值化 还计划进行模拟以确定参数的影响，例如 血管直径、长度、血细胞计数、红细胞停留时间等 振荡的幅度和频率。数值研究也将 探索周期加倍和混沌波动的可能性，如 问题中的参数是不同的。 预期的结果将提供一个非线性动力学模型，通过它 需要审视生物防治机制的概念。摇摆 非线性效应产生的流动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。时变的流量是 也牵涉到血管壁的健康。

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.