Pulmonary Aerodynamic Valves: Distribution & Function

肺空气动力阀：分布

• 批准号: 2039477
• 负责人: Colleen Farmer
• 金额: $ 56.65万
• 依托单位: University of Utah
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-15 至 2024-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2039477&HistoricalAwards=false
• 关键词: Pulmonary; Aerodynamic; Valves; Distribution; &amp

This project addresses a major, poorly understood question in vertebrate evolution related to the lung's extraordinary structural diversity, especially the structures that give rise to one-way airflow. Bird lungs have held a special place in this regard, because their design is so radically different from mammalian lungs, and it has been thought that one-way airflow is related to the energetic demands of flight. However, the lungs of other non-flying vertebrate animals, including snakes, turtles, and chameleons, also differ from those of mammals. This research will provide a better understanding of how aerodynamic valves in the lungs of reptiles give rise to one-way airflow, the physiological significance of these patterns of flow, and their distribution across vertebrate animals. It will reveal fundamental, form-function relationships linking lung structures to patterns of airflow in reptiles and amphibians; enhance understanding of the effects of these patterns of airflow on gas exchange, respiratory water loss, and heat loss; and be applied to reconstruction of the respiratory systems of extinct tetrapods. The project also includes significant educational and outreach activities, including science communication training for lab personnel, participation in public-education, distance-learning programs run by Utah's Hogle Zoo, and development of virtual reality infrastructure for research, outreach, and teaching.Three primary activities will result from the proposed research. (1) A phyletic survey will be made of patterns of airflow in the lungs of amphibians and reptiles. (2) Tests of the following hypotheses for the mechanistic basis of pulmonary aerodynamic valves will be made by measurements and visualizations of patterns of airflow, computational fluid dynamics simulations, and physical models: i) that turtles have a pulmonary Tesla valve; ii) that the expiratory valve of archosaurs functions like an internal nozzle, where a Coanda surface induces and amplifies flow; iii) that the expiratory valve arises from a caudal guiding dam. (3) Balloon catheters will be implanted into the lungs of alligators which will allow unidirectional flow to be converted to tidal airflow. Under these two flow regimes hypotheses for the functional significance of aerodynamic valves will be tested: i) that alligators have counter-current or cross-current gas exchange; ii) that unidirectional flow reduces rates of evaporative water and heat loss, and improves wash-out of lung CO2 and wash-in of O2. Measurements will made of O2 extraction and CO2 removal with each breath, rates of lung washout of CO2, rates of respiratory evaporative water loss and heat loss, and rates of ventilation relative to rates O2 consumption and CO2 excretion. The proposed research has four strands of educational and outreach broader impacts: 1) Recruitment of underrepresented participants into STEM; 2) Training of lab personnel in science communication, working closely with the Natural History Museum of Utah; 3) Outreach to the lay community, including K-12 schools, through distance-learning programs of Utah's Hogle Zoo; 4) Development of virtual reality infrastructure for research, outreach, and teaching.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.

这个项目解决了脊椎动物进化中一个主要的、知之甚少的问题，这个问题与肺非凡的结构多样性有关，特别是引起单向气流的结构。鸟类的肺在这方面占有特殊的地位，因为它们的设计与哺乳动物的肺完全不同，并且人们认为单向气流与飞行的能量需求有关。然而，其他非飞行脊椎动物的肺，包括蛇，海龟和变色龙，也不同于哺乳动物。这项研究将更好地了解爬行动物肺部的气动阀如何产生单向气流，这些流动模式的生理意义，以及它们在脊椎动物中的分布。它将揭示爬行动物和两栖动物的肺结构与气流模式之间的基本形式-功能关系;增强对这些气流模式对气体交换，呼吸水分损失和热量损失的影响的理解;并应用于重建已灭绝的四足动物的呼吸系统。该项目还包括重要的教育和推广活动，包括实验室人员的科学交流培训，参与公共教育，由犹他州的Hessel动物园运行的远程学习计划，以及为研究，推广和教学开发虚拟现实基础设施。(1)将对两栖动物和爬行动物肺部的气流模式进行系统调查。(2)将通过测量和可视化气流模式、计算流体动力学模拟和物理模型来检验以下关于肺空气动力学阀的机械基础的假设：i）海龟有肺特斯拉阀; ii）祖龙的呼气阀功能类似于内部喷嘴，其中柯恩达表面诱导和放大流动; iii）呼气阀由尾部引导坝引起。(3)将球囊导管植入短吻鳄的肺中，这将允许将单向气流转换为潮汐气流。在这两种流动状态下，将测试气动阀功能意义的假设：i）鳄鱼具有逆流或交叉流气体交换; ii）单向流动降低了蒸发水和热损失的速率，并改善了肺CO2的冲洗和O2的冲洗。将测量每次呼吸的O2提取和CO2清除率、CO2的肺冲洗率、呼吸蒸发失水率和热损失率以及相对于O2消耗率和CO2排泄率的通气率。拟议的研究有四个方面的教育和推广更广泛的影响：1）招募代表性不足的参与者进入STEM; 2）与犹他州自然历史博物馆密切合作，对实验室人员进行科学传播培训; 3）通过犹他州的Humble动物园的远程学习计划，推广到非专业社区，包括K-12学校; 4）为研究、推广和教学开发虚拟现实基础设施。该奖项反映了NSF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。