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

许多鱼通过使用它们的下颚来摄取肉块，并且经常用它们刚性的身体骨骼产生运动来移除肉块。人们对盲鳗知之甚少，它也能有效地完成这项任务，尽管它没有下颚，甚至没有脊椎。盲鳗依靠柔软肌肉和结缔组织的复杂排列来协调有力和动态的运动：1）独特的齿板，可以切下大块食物，2）柔软的身体，松弛的皮肤可以打结。 身体结被压在尸体的表面，这样八目鳗就可以获得杠杆作用来支持齿板功能。本研究试图描述与使用软组织机制产生力和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学硕士提供培训，并启动国家和国际合作。PI和他们的学生将与当地三个公共水族馆合作，开发展示独特的盲鳗生物力学和行为的展品。最后，盲鳗的身体模型和模拟可能会导致实际应用的发展，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。首先，齿板运动的生物力学分析将开始于基于解剖和二维-三维X射线成像的形态学分析。将通过分析喂食过程中的高速视频和肌肉活动记录来测试力是如何产生和传递的。第二，松散的八目鳗皮肤的形态和材料特性可能对体结操作非常重要。将使用组织学重建描述皮肤形态，并使用双轴拉伸试验测量材料特性。然后，这些数据可以被用作输入到一个简化模型的盲鳗身体，基于一个灵活的绳模型的鞘/芯设计，在其上模拟结的形成和滑动。 第三，为了评估身体打结行为对盲鳗“咬”力的贡献，将食物拴在其上的定制水下力平台将记录剪切力和身体打结反作用力的大小和方向。研究结果将通过在同行评审的期刊上发表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.