initial gas filling of the tracheal system (tracheal filling) in embryos of the tobacco hornworm Manduca sexta (Sphingidae, Insecta). Main focus is the role of cavitation and the importance of solid/liquid/gas interactions at the tracheal wall.

烟草天牛(Manduca Sexta)的胚胎在卵中发育时使其气管系统具有功能。这一过程之所以引人注目，有两个原因。首先，气管充气是在不接触外部空气的情况下进行的；气泡在液体中从头产生。其次，这个过程非常快。气管系统在不到五分钟的时间内就能发挥作用。这表明空化触发气管填充。该项目通过操纵影响空化可能性或时间的因素，以前所未有的详细方式了解Manduca胚胎气管系统中的空化。这些因素是卵子内的压力、气管壁的微观结构，以及随着角质层硬化而发生的管壁表面化学变化。第二个目标是揭示空化发生后气管液体从气管腔中排出的机制。存在两种主要的替代方案。首先，水可能会从整个气管壁上消失。墙的表面积相对较大，但硬化层应该是不透水的。其次，水可能只在气管(气管)的顶端消失，那里的角质层薄且未硬化。气管充盈提供了一个由固-液-气相互作用产生的强大表面力的生物学例子。拟议的项目将深入了解这三个阶段的相互作用在昆虫关键的呼吸转变过程中所起的作用。此外，这些类型的相互作用在材料科学(功能表面、莲花效应)和微流体(芯片实验室应用)中是基本的。我们认为，对生物进化如何塑造这些相互作用的详细研究，可能会阐明人们广泛感兴趣的基本工程问题。

Embryos of the tobacco hornworm (Manduca sexta) render their tracheal system functional while developing in the egg. The process is remarkable for two reasons. First, tracheal gas filling occurs without contact to outside air; gas bubbles are generated de novo in liquid. Second, the process is very fast. The tracheal system becomes functional in less than five minutes. This indicates that cavitation triggers tracheal filling.The project serves to understand cavitation in the tracheal system of Manduca embryos in unprecedented detail by manipulating factors that affect the likelihood or timing of cavitation. Those factors are the pressure inside the egg, the micro-structure of the tracheal wall, and the change in the surface chemistry of the wall that occurs with sclerotization of the cuticle.A second goal is to uncover the mechanism by which the tracheal liquid is eliminated from the tracheal lumen after cavitation has occurred. Two main alternatives exist. First, water may disappear through the whole tracheal wall. The wall has relatively large surface area, but the sclerotized cuticle is supposed to be impermeable to water. Second, water may disappear only at the tips of the tracheae (tracheoles), where the cuticle is thin and unsclerotized.Tracheal filling provides a biological example of strong surface forces arising from solid-liquid-gas interactions. The proposed project will give insight into the role these three-phase interactions play during a critical respiratory transition in insects. In addition, these kinds of interactions are fundamental in materials science (functional surfaces, lotus effect) and micro-fluidics (lab-on-a-chip applications). We think that detailed study of how biological evolution has shaped these interactions may illuminate basic engineering problems of wide interest.