Collaborative Research: Transport of model-virus through the lung liquid lining

导致COVID-19大流行的新型冠状病毒SARS-CoV-2与SARS-CoV（2002年）和MERS-CoV（2012年）等其他呼吸道冠状病毒相似。所有这些病毒都造成危险的呼吸系统疾病，死亡率高，对社会造成严重影响。这种病毒破坏产生肺表面活性剂的细胞，这些表面活性剂能防止肺泡气囊塌陷，最终使肺部充满液体。肺液壁、肺表面活性剂和呼吸道病毒之间的流体动力学相互作用目前还不清楚。该项目通过进行实验和数值模拟来捕捉模型病毒与肺表面活性剂相互作用的基本流体动力学，从而解决了这一空白。数值模型随后将用于模拟生理相关的尺度，而这些尺度无法通过实验获得。除了了解肺液体衬里的流动，目前在界面膨胀和压缩预测建模方面的知识差距阻碍了其他领域的发展，例如水波，这在大气和海洋之间二氧化碳气体交换的建模中至关重要。肺表面活性剂的两个主要功能是调节肺泡液体内壁的界面张力和表面粘度，并提供抵抗空气传播病原体的第一道免疫防线。将开发小颗粒在表面活性剂覆盖的液体层中传输的预测模型。在提出的表面弹性模型中，一个关键的进步是测量单层在相应状态下的状态方程，该状态对应于它遭受大量膨胀/压缩循环时的状态。通常的方法来确定一个新近展开的单层在缓慢压缩下的性质是不适合模拟与振荡体流耦合的单层流体力学，因为单层处于不同的状态，具有非常不同的界面性质。界面膨胀粘度的作用及其相对于表面弹性的重要性仍然知之甚少，这是自由表面流动预测建模的主要障碍。pi在多学科合作方面有着良好的记录，并将继续为研究生和本科生提供独特的教育机会。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The novel coronavirus SARS-CoV-2, responsible for the COVID-19 pandemic, is similar to other respiratory coronaviruses, such as SARS-CoV (2002) and MERS-CoV (2012). All these viruses cause dangerous respiratory disorders with high mortality and grave impacts on society. This virus destroys the cells that produce lung surfactants which, among other things, keep the alveoli air-sacks from collapsing, and eventually the lungs fill with liquid. The fluid dynamic interactions between the liquid lining of the lung, the lung surfactants, and the respiratory virus are presently not well understood. This project addresses this gap by conducting experiments and numerical modeling to capture the essential fluid dynamics of a model virus interacting with lung surfactant. The numerical models will then be used to simulate physiologically relevant scales, not accessible experimentally. In addition to understanding flow in the lung liquid lining, the present knowledge gap in predictive modeling of interfacial dilation and compression is hampering developments in other areas, such as in water waves, which are of utmost importance in modeling of carbon dioxide gas exchange between the atmosphere and the oceans.The two primary functions of lung surfactants are regulating the interfacial tension and surface viscosities of the liquid lining of the alveoli, and providing a first line of immune defense against airborne pathogens. Predictive models for the transport of small particles in a surfactant-covered liquid layer will be developed. A key advancement in the proposed modeling of surface elasticity is to measure the equation-of-state of the monolayer in a state corresponding to that found when it has been subjected to a large number of dilation/compression cycles. The usual approach of determining properties of a recently spread monolayer undergoing slow compression is inappropriate for modeling monolayer hydrodynamics coupled to an oscillatory bulk flow, as the monolayer is in a different state with very different interfacial properties. The role of interfacial dilatational viscosity and its significance relative to surface elasticity remains poorly understood and presents a major impediment to the predictive modeling of free-surface flows. The PIs have a proven track record of productive multidisciplinary collaboration, and will continue to provide a unique educational opportunity for the graduate and undergraduate students.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.