Understanding how the rheological behavior of biological fluids is related to health

PI: Schultz， william提案号：1604903该提案基于这样一个假设，即健康是通过生物体液的变化来反映的，其中最重要和最容易获得的是唾液，这些变化影响生物体液的流变特性。这一假设进一步规定，唾液流变学特征及其特性的量化可以提供有关个人健康的信息。唾液流变学与水的流变学相似，这使得测量非牛顿性质变得困难。毛细管破裂流变法（CBR）通常用于确定此类流体的拉伸参数。提出用微分一维模型重新检验CBR基础，以消除测量细丝中点半径变薄率时所需的较大校正因子。与以前的方法不同，新的分析方法可以识别驱动流动的曲率梯度，因此需要自由表面剖面的演化来准确确定拉伸特性。这一分析与在牛顿理论和初步唾液实验中观察到的丝状结构的演化过程是一致的。接下来，牛顿分析中空间变化的表面张力被用于研究表面活性剂在细丝动力学中的作用，以及长链分子（如粘蛋白）或表面活性剂（如肥皂膜）更突出的拉伸粘弹性特性，这可以解释为粘性。与唾液粘弹性不同，表面活性在唾液细丝形成中的作用及其对健康诊断的意义尚未被考虑。表征唾液流变特性可以指导开发更有效的唾液替代品、兴奋剂和用于口干或吞咽困难的水合液体。联合pi将与美国加纳生物医学工程系合作，研究当地人口中普遍存在的吞咽困难问题。通过该项目开发的技术可以帮助表征其他生物和工业流体。此外，还计划开展促进工程领域女性发展的活动，包括通过密歇根大学FEMMES项目向200多名4年级至6年级女生提供教育服务，并让本科生女性参与研究。

PI: Schultz, WilliamProposal Number: 1604903This proposal is based upon the hypothesis that health is reflected by changes in biological fluids, most important and accessible of which is saliva, and these changes affect the rheological properties of biofluids. This hypothesis further stipulates that rheological characterization of saliva, and quantification of its properties, can provide information about a person's health. Saliva rheology is similar to that of water, making measuring non-Newtonian properties difficult. Capillary Break-up Rheometry (CBR) is commonly used to determine extensional parameters of such fluids. It is proposed to re-examine CBR foundations with differential one-dimensional models to eliminate the large correction factors required when measuring the radius-thinning rate at the filament midpoint. Unlike previous methods, new analysis recognizes curvature gradients that drive the flow and therefore the free surface profile evolution is required to accurately determine extensional properties. This analysis is consistent with filament evolution all the way through beads-on-a-string formation that they have been observed in Newtonian and preliminary saliva demonstrations. Next the spatially-varying surface tension in Newtonian analysis is used to study the role of surfactants in filament dynamics as well as the more prominent extensional viscoelastic properties of long-chained molecules (such as mucins) or by surfactants (such as in soap films) that could be interpreted as stickiness. Unlike saliva viscoelasticity, the role of surface activity in saliva filament formation and its implications on health diagnosis have not yet been considered. Characterizing saliva rheological properties could guide the development of more effective saliva substitutes, stimulants, and hydrating liquids for xerostomia or dysphagia. The co-PIs will collaborate with U. Ghana Biomedical Engineering Department to study dysphagia problems prevalent in local populations. Techniques developed through this project can help to characterize other biological and industrial fluids. There are also plans to engage in activities to promote women in engineering including educational outreach to over 200 4th through 6th grade girls through the University of Michigan FEMMES program and involving undergraduate women in research.