Theoretical Problems in Soft Matter and Quantitative Biology

技术总结该奖项支持材料科学、统计物理和生物物理学之间的理论研究和教育。PI将研究由位错介导的杆状细菌细胞壁的伸长和弯曲，以及吸附在圆柱体上的胶体颗粒组件中的相关现象。就细菌而言，显著的糖链延伸机械推动了系统的位错攀升，导致了生长动力学，这在传统材料科学中几乎没有类似的东西。位错轨迹应受到长程弹性相互作用以及通过Peach-Kohler力产生的外部应力和膨胀压力的影响。固体圆柱体上的胶体以滑动动力学为主。由于孤立位错沿圆柱轴的Burgers矢量表现为致密的晶界，通过滑动的分离可能能够调节不同叶系粒子堆积之间的转变。在另一个推力中，PI将使用非平衡统计动力学、种群遗传学和概率论的工具来解决与迁移、竞争和合作相关的问题。这些现象在许多物种的历史上都发挥了关键作用，无论是在固体表面上，如入侵物种的迁徙中，还是在细菌入侵动物组织的过程中，以及在海洋等液体环境中，在存在液体平流的情况下，蓝藻和浮游植物等光合作用生物相互竞争。考虑到范围的扩大，PI将研究微生物之间的互惠竞争如何在二维和三维的固体环境中发挥作用，特别强调前沿波动与通胀动态相结合的影响。由于地球的大部分进化史发生在河流、湖泊和海洋中，PI还将研究离散生物的固定时间和概率，这些生物在平流流体流动(包括高雷诺数湍流)下繁殖和竞争。尤其有趣的现象出现在微生物的倍增时间处于科尔莫戈罗夫式的涡流翻转时间级联的中间。这个项目提供了一个不同寻常的跨学科环境，教育和培训学生现代凝聚态理论、材料理论、统计物理和生物物理，部分地将理论应用于与环境、可持续性和生物启发材料有关的问题。非技术总结该奖项支持材料科学、统计物理和生物物理之间的理论研究和教育。微生物之间的合作是许多复杂系统的核心。例如，肠道细菌可以帮助动物宿主消化纤维素。在生态系统层面上，植物通常依靠真菌来获得重要的营养物质。甚至人类社会也是个人之间合作的产物。尽管互惠互利具有明显的优势和普遍性，但它的存在往往很难解释：合作可能会屈服于欺骗和随机数字波动。对固体表面和海洋等动态环境中的微生物如何竞争和合作的详细理论将使我们更好地理解我们星球和生物物质的生态，这将对生物有机体启发的先进材料产生影响。这项研究对于增进对细胞壁如何赋予生长中的微生物以形状和强度的理解也是重要的。特别令人感兴趣的是革兰氏阴性细菌，其细胞壁由由大的链状分子组成的软链组成的薄网组成。这个项目提供了一个不同寻常的跨学科环境，教育和培训学生现代凝聚态理论、材料理论、统计物理和生物物理，部分地将理论应用于与环境、可持续性和生物启发材料有关的问题。

TECHNICAL SUMMARYThis award supports theoretical research and education at the interface between materials science, statistical physics and biophysics. The PI will study dislocation-mediated elongation and bending of rod-shaped bacterial cell walls, and related phenomena in colloidal particle assemblies adsorbed on cylinders. In the case of bacteria, remarkable glycan strand extension machinery powers systematic dislocation climb, leading to growth dynamics with few analogs in conventional materials science. Dislocation trajectories should be influenced by long-range elastic interactions and by external stresses and turgor pressure via the Peach-Kohler force. Glide dynamics dominates for colloids on solid cylinders. Because isolated dislocations with Burgers vectors along the cylinder axis behave like compact grain boundaries, separation via glide may be able to mediate transitions between different phyllotactic particle packings.In another thrust, the PI will use the tools of non-equilibrium statistical dynamics, population genetics and probability theory to address issues related to migrations, competition and cooperation. These phenomena have played a crucial role in the history of many species, on both solid surfaces, as in migrations of invasive species, or bacterial invasions of animal tissue, and in liquid environments such as the ocean, where photosynthetic organisms such as cyanobacteria and phytoplankton compete in the presence of fluid advection. With range expansions in mind, the PI will study how mutualistic competitions between microorganisms play out in solid environments in two and three dimensions, with a particular emphasis on the effect of front undulations combined with inflationary dynamics. Because much of earth's evolutionary history took place in rivers, lakes and oceans, the PI will also study fixation times and probabilities for discrete organisms that reproduce and compete subject to advecting fluid flows, including high Reynolds number turbulence. Especially interesting phenomena arise for microorganisms whose doubling times are in the middle of a Kolmogorov-like cascade of eddy turnover times. This project provides an unusual interdisciplinary environment to educate and train students in modern condensed matter theory, materials theory, statistical physics, and biological physics to bring theory to bear, in part, on problems related to the environment, sustainability, and biologically inspired materials.NONTECHNICAL SUMMARYThis award supports theoretical research and education at the interface between materials science, statistical physics and biophysics. Cooperation among microorganisms is at the heart of many complex systems. For example, gut bacteria can help animal hosts digest cellulose. On an ecosystem level, plants often rely on fungi to receive important nutrients. Even human societies are products of cooperation between individuals. Despite the apparent advantage and pervasiveness of mutualism, its existence is often difficult to explain: Cooperation can succumb to cheating and to stochastic number fluctuations. A detailed theory of how microorganisms on solid surfaces and in dynamic environments such as the ocean compete and cooperate will lead to a better understanding of the ecology of our planet and living matter with implications for advanced materials inspired by biological organisms. This research is also important to advance understanding of how cell walls endow growing microorganisms with a shape and strength. Of particular interest are gram-negative bacteria, whose cell walls consist of a thin meshwork of soft strands composed of large chain-like molecules. An improved understanding of growth mechanisms could lead to more efficient antibiotics, and better remediation of human and animal diseases.This project provides an unusual interdisciplinary environment to educate and train students in modern condensed matter theory, materials theory, statistical physics, and biological physics to bring theory to bear, in part, on problems related to the environment, sustainability, and biologically inspired materials.