Collaborative Research: Reconstructing Airflow in the Nasal Cavity of Mammals

哺乳动物的鼻子有一套像纸一样薄的骨头，叫做鼻甲。涡轮机与嗅觉和调节空气有关，但它们的功能尚不清楚。这是事实，尽管更好地了解鼻腔解剖和功能对于预测人体呼吸道颗粒沉积、改善鼻内药物输送以及开发用于探测爆炸物等危险物质的人工嗅探器的进展至关重要。关于涡轮功能的一些最重要的问题涉及气流通过鼻子的各个方面。它们如何引导空气进入嗅觉区？呼吸和嗅觉有不同的途径吗？不同物种在涡轮结构上的差异能告诉我们什么关于气味接收和热量和水保护的效率？为了回答这些问题，这个项目汇集了来自生物学和工程学两个不同领域的科学家，以推进我们对呼吸和嗅觉的理解。通过结合现代高分辨率医学成像、最先进的流动模型和鼻腔软组织分布数据，这一跨学科合作将首次应用新的计算建模工具（例如，三维解剖重建、计算流体动力学[CFD]）和实验测量技术（例如，使用解剖正确的透明物理模型）来开发鼻子的新形式-功能关系。为此，五种哺乳动物的三维鼻腔解剖结构将通过完整头部的磁共振成像（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进行重建。为了进行未来的研究，将使用完整头部的成对MRI扫描和清洁头骨的CT扫描来开发一种方法，该方法可以校正干燥颅骨标本中鼻粘膜缺失的CT衍生图像数据。这将允许研究鼻腔气流单独使用现有的博物馆收藏的头骨，而不是完整的头部，从而大大扩大物种和功能的范围，可以研究。最后，为了增加对鼻部功能的了解，除了最受关注的两个相对较短的鼻部群体，即灵长类动物和食肉动物，将通过CT扫描重建10-15种有蹄类动物的鼻翼，并分析其鼻翼尺寸。将生成超过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MRI扫描和3个单独哺乳动物头骨的CT扫描。所有新的扫描结果将在获得该项目资助的5年内存放在德克萨斯大学奥斯汀分校的NSF数字形态学图书馆（www.digimorph.org）供公众访问。同样，本研究期间开发的所有数值CFD模型将通过由pi建立并由宾夕法尼亚州立大学托管的网站提供。作为这个项目的一部分，许多研究生和本科生将接受生物学和工程学方面的培训。少数民族研究生和本科生将通过各机构的专门项目招募，调查人员将继续向高中生和非专业观众进行持续的推广工作。

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.