Collaborative: IOS Full Proposal: RUI: Biting hard with soft feeding apparatuses

许多鱼通过用它们的下巴剪下肉块来进食，并经常用它们僵硬的身体骨架来产生运动来移走肉块。尽管没有下巴，甚至没有脊椎，但鲜为人知的鳗鱼也能有效地完成这项任务。鳗鱼依靠复杂的软肌肉和结缔组织的排列来协调有力和动态的运动，1)独特的牙板可以剪下大块食物，2)皮肤松散的灵活身体可以打结。身体结被压在身体的表面上，这样八目鳗就可以获得支撑牙板功能的杠杆。这项研究试图描述与产生力量和使用软组织机制进行精确运动相关的功能原理。此外，这项研究将为四名本科生和一名理科硕士学生提供培训，并发起国内和国际合作。PI和他们的学生将与当地的三个公共水族馆合作，开发展示独特的八目鳗生物力学和行为的展品。最后，鲱鱼的身体模型和模拟可能导致实际应用的发展，例如具有动态打结能力的安全绳和可变形材料机制的生物灵感。本项目包括三部分分析。首先，牙板移动的生物力学分析将从基于解剖和二维和三维X射线成像的形态分析开始。由此得出的关于力量是如何产生和传递的假设将通过对喂食比赛期间的高速视频和肌肉活动记录的分析进行测试。其次，松散的鳗鱼皮肤的形态和材料特性可能对身体打结操作非常重要。皮肤形态将使用组织重建进行描述，材料特性将使用双向拉伸测试进行测量。然后，这些数据可用作输入到基于鞘/芯设计的弹性绳索模型的鳗鱼身体的简化模型中，在该绳索模型上模拟结的形成和滑移。第三，为了评估身体打结行为对鳗鱼咬人力量的贡献，一个定制的水下力量平台，食物将被拴在上面，将记录剪切力和身体打结反作用力的大小和方向。研究结果将通过发表在同行评议的期刊上和在科学会议上传播。

Many fish feed by using their jaws to scissor away pieces of flesh and often generate movements with their rigid body skeletons to remove the piece. The poorly understood hagfish can also effectively accomplish this task despite lacking jaws or even a spine. Hagfish rely on complex arrangements of soft muscle and connective tissues to coordinate forceful and dynamic movements of 1) a unique toothplate that can shear off large chunks of food, and 2) flexible bodies with loose skins that can be tied into knots. Body knots are pressed against the surface of the carcass so that hagfish can gain leverage to support toothplate function. This study attempts to describe principles of function associated with generation of force and precision movements using soft tissue mechanisms. In addition, this research will provide training for four undergraduates and one Master of Science student and initiate national and international collaborations. The PIs and their students will work with three local public aquaria to develop exhibits that showcase unique hagfish biomechanics and behaviors. Finally, hagfish body models and simulations may result in the development of practical applications, such as safety ropes with dynamic knotting capabilities and bio-inspiration for deformable material mechanisms.This project encompasses a three-part analysis. First, the biomechanical analysis of toothplate movement will begin with a morphological analysis based on dissections and two- & three-dimensional X-ray imaging. Resulting postulates of how forces are produced and transmitted will be tested using analyses of high-speed video and muscle activity recordings during feeding bouts. Second, the morphology and material properties of the loose hagfish skin are likely very important to body knot manipulations. Skin morphology will be described using histological reconstructions and material properties will be measured using biaxial tensile tests. These data may then be used as input into a simplified model of the hagfish body, based on a flexible rope model of a sheath/core design, upon which to simulate knot formation and slippage. Third, in order to assess the contribution of body knotting behavior to hagfish 'bite' strength, a custom underwater force platform, to which food will be tethered, will record the magnitude and direction of shearing and body knot reaction forces. Results from the studies will be disseminated through publication in peer-reviewed journals and at scientific meetings.