Mass Transfer Phenomena in the Lymphatic System

淋巴系统中的传质现象

• 批准号: 1846150
• 金额: --
• 依托单位: Imperial College London
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-1846150
• 关键词: Mass; Transfer; Phenomena; Lymphatic; System

The primary aim of this research project is to quantify the contractility of lymphatic muscle cells (LMCs) across multiple scales for a range of diastolic diameters and transmural pressures. This aim is motivated by the importance of contractile force in lymph propulsion and the generation of pressure differences required for the function of lymphatic valves. The knowledge gained from this research will be incorporated into multi-scale models of flow in the lymphatic system, which are based on lumped parameter and computational mass transport approaches. This is to be done using both experimental and computational methods, with the main experiments being performed by collaborators and theoretical models then being developed as part of the research project. The experiments will be performed to obtain data required for determining contractile force as a function of the upstream and downstream pressures. Two series of experiments will be performed, the first series will consist of cannulating lymphatic vessels, varying the pressure and measuring both the internal and external vessel diameters. The second series of experiments will use a wire myograph to determine the length-tension relationship of isolated lymphatic vessels. This project will then use computational methods required to process the experimental results because the contractility of the LMCs can only be measured indirectly. The determination of contractility from experimental results is to be based on balancing the circumferential forces. Geometrical data and measurements of the pressure within the lymphangion from the first series of experiments will be combined for the calculation of contractile force. Analysis of the second series of experiments will calculate the contractile tension from measurements of the force transducer and average wall thickness, and the results will be compared with a finite element model of five or more lymphangions. Further modelling based on current models of smooth muscle cells will be required for incorporation of the contractility into the lymphatic flow models. This research will be original as there is currently no single model of smooth muscle that can be applied to all systems and the smooth muscle in lymphatics is significantly different from that in the systems which have been the focus of research. This research will therefore be the first to quantify and model the contractility of LMCs over the physiologic range.The project will also include involvement in the other research aims of the research group, which are to characterize the resistance and hysteresis of lymphatic valves, and to develop models of fluid flow and leukocyte behaviour in lymph nodes. The results from these aims will also be incorporated into multi-scale models of the transport phenomena of the lymphatic system. Characterization of the lymphatic valves will involve experimental characterization of valves and computational models of the solid and fluid mechanics involved, which will ultimately be combined in a fluid-structure interaction model. Modelling the lymph nodes will involve computational fluid dynamics of lymph flow through the node, and agent-based modelling of the cells in lymph nodes. The computational fluid dynamics and agent-based models will ultimately be coupled to provide a more comprehensive model of lymph nodes.

本研究项目的主要目的是在舒张直径和跨壁压范围内的多个尺度上量化淋巴肌细胞（LMC）的收缩性。这一目的是由淋巴推进中的收缩力的重要性和淋巴阀功能所需的压力差的产生所激发的。从这项研究中获得的知识将被纳入淋巴系统中的多尺度流动模型，该模型基于集总参数和计算质量传输方法。这将使用实验和计算方法来完成，主要实验由合作者进行，然后作为研究项目的一部分开发理论模型。将进行实验以获得确定收缩力所需的数据，收缩力是上游和下游压力的函数。将进行两个系列的实验，第一个系列将包括插管淋巴管，改变压力和测量内外血管直径。第二系列实验将使用钢丝肌描记器来确定离体淋巴管的长度-张力关系。然后，该项目将使用处理实验结果所需的计算方法，因为LMC的收缩性只能间接测量。根据实验结果确定收缩性是基于平衡周向力。将结合第一系列实验的几何数据和淋巴管内压力测量值来计算收缩力。第二系列实验的分析将根据力传感器和平均壁厚的测量值计算收缩张力，并将结果与五个或更多个淋巴管的有限元模型进行比较。将收缩性纳入淋巴流模型需要基于平滑肌细胞当前模型的进一步建模。这项研究将是原创性的，因为目前没有一个单一的平滑肌模型可以应用于所有系统，并且血管力学中的平滑肌与研究重点的系统中的平滑肌显著不同。因此，这项研究将是第一个在生理范围内量化和模拟LMC收缩性的研究，该项目还将包括参与研究小组的其他研究目标，即表征淋巴阀的阻力和滞后，并开发淋巴结中液体流动和白细胞行为的模型。从这些目标的结果也将被纳入淋巴系统的运输现象的多尺度模型。淋巴管瓣膜的表征将涉及瓣膜的实验表征以及所涉及的固体和流体力学的计算模型，这些模型最终将结合在流体-结构相互作用模型中。对淋巴结进行建模将涉及通过淋巴结的淋巴流的计算流体动力学，以及淋巴结中细胞的基于代理的建模。计算流体动力学和基于代理的模型将最终耦合，以提供一个更全面的淋巴结模型。