Collaborative Research: Reconstructing Airflow in the Nasal Cavity of Mammals

哺乳动物的鼻子里有一组复杂的纸一样薄的骨骼，被称为鼻甲。海龟同时参与嗅觉和空调激发的空气，但它们的功能还没有被很好地理解。这是事实，尽管更好地了解鼻部解剖和功能对于预测人体呼吸道中的颗粒沉积、改进鼻腔给药以及开发用于检测爆炸物等危险物质的人工嗅探器是至关重要的。关于涡轮机功能的一些最重要的问题涉及到通过鼻子的气流的一些方面。它们如何将空气引导到嗅觉区？呼吸和嗅觉有不同的途径吗？不同物种在鼻甲结构上的差异能告诉我们什么关于气味接收、热量和水资源保护的效率？为了回答这些问题，这个项目将生物学和工程学这两个不同领域的科学家聚集在一起，以促进我们对呼吸和嗅觉的理解。通过将现代高分辨率医学成像、最先进的血流模型和鼻部软组织分布数据相结合，这种跨学科的合作将率先应用新型计算建模工具(例如，3D解剖重建、计算流体力学[CFD])和实验测量技术(例如，使用解剖学上正确的透明物理模型)来开发鼻部的新形式-功能关系。为此，将根据完整头部的磁共振图像(MRI)、骨鼻甲的计算机断层扫描(CT)以及嗅觉和呼吸组织分布的实验室分析，重建五种哺乳动物的三维鼻部解剖结构。为了便于将来的研究，将使用成对的完整头部的MRI扫描和清理后的头骨的CT扫描来开发一种方法，以校正干燥的头骨标本的CT图像数据，以消除鼻黏膜的缺失。这将允许仅使用博物馆现有的头骨收藏而不是完整的头部来研究鼻腔气流，从而极大地扩大了可以研究的物种和功能的范围。最后，为了增加对鼻功能的了解，超出了两个相对较短的鼻子组，即灵长类和食肉动物，将根据CT扫描的干燥头骨重建10-15种有蹄类动物的鼻甲，并分析鼻甲的尺寸。将产生超过10,000个11-16种哺乳动物头骨的CT切片，以及成对的完整头部的MRI扫描和三个单独哺乳动物的头骨CT扫描。所有新的扫描将在收到该项目的资金后5年内存放在德克萨斯大学奥斯汀分校的NSF数字形态图书馆(www.digimform.org)，供公众使用。同样，在本研究期间开发的所有CFD数值模型将通过由PIS建立并由宾夕法尼亚州立大学托管的网站提供。作为该项目的一部分，许多研究生和本科生将接受生物学和工程学方面的培训。少数族裔研究生和本科生将通过每个机构的专门计划招募，调查人员将继续进行针对高中生和非专业观众的外展工作。

The mammalian nose houses a complex set of paper-thin bones known as turbinals. Turbinals are involved in both the sense of smell and conditioning inspired air, and yet their function is not well understood. This is true despite the fact that a better knowledge of nasal anatomy and function is essential for progress in predicting particulate deposition in human airways, improving intranasal drug delivery, and the development of artificial sniffers for the detection of dangerous substances such as explosives. Some of the most important questions about turbinal function concern aspects of airflow through the nose. How do they direct air to the olfactory region? Are there separate pathways for respiration and olfaction? What can differences among species in the architecture of the turbinals tell us about the efficiency of odorant reception and heat and water conservation? To answer these questions, this project brings together scientists from two disparate fields, biology and engineering, to advance our understanding of respiration and olfaction. By combining modern high-resolution medical imaging, state-of-the-art models of flow, and data on nasal soft tissue distribution, this cross-disciplinary collaboration will be the first to apply novel computational modeling tools (e.g., 3-D anatomical reconstruction, computational fluid dynamics [CFD]) and experimental measurement techniques (e.g., use of anatomically-correct transparent physical models) to develop new form-function relationships for the nose. To do so, the 3-D nasal anatomy of five mammal species will be reconstructed from magnetic resonance images (MRI) of intact heads, computed tomography (CT) scans of their bony turbinals, and laboratory analysis of the distribution of olfactory vs. respiratory tissue. To enable future studies, paired sets of MRI scans of intact heads and CT scans of the cleaned skulls will be used to develop a method that corrects CT-derived image data of dry skull specimens for the absence of nasal mucosa. This will permit the study of nasal airflow using existing museum collections of skulls alone rather than intact heads, thereby greatly expanding the range of species and function that can be studied. Finally, to increase knowledge of nasal function beyond the two relatively short-snouted groups that have received the most attention, viz., primates and carnivores, the turbinals of 10-15 ungulate species will be reconstructed from CT scans of dry skulls and analyzed for turbinal dimensions. Over 10,000 CT slices of the skulls of 11-16 species of mammals, as well as paired sets of MRI scans of intact heads and CT scans of skulls for three individual mammals will be generated. All new scans will be deposited in the NSF Digital Morphology Library at the University of Texas, Austin (www.digimorph.org) for public access within 5 years of receiving funding for this project. Similarly, all of the numerical CFD models developed during this study will be made available via a website to be established by the PIs and hosted by Penn State University. Numerous graduate students and undergraduates will be trained in aspects of both biology and engineering as part of this project. Minority graduate and undergraduate students will be recruited through dedicated programs at each institution, and the investigators will continue their ongoing outreach efforts to high school students and lay audiences.