Theoretical Problems in Soft Matter and Quantitative Biology

软物质和定量生物学的理论问题

• 批准号: 1608501
• 负责人: David Nelson
• 金额: $ 40.5万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-15 至 2020-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1608501&HistoricalAwards=false
• 关键词: Theoretical; Problems; Soft; Matter; Quantitative

NONTECHNICAL SUMMARYThis award supports theoretical research and education to exploit the power of statistical physics to gain insight into complex systems that lie at the interface of biology, physics, and materials science. The approach applies understanding of materials and materials-related phenomena across disciplinary boundaries into biologically inspired problems with potential implications for applications. The project contains three major aims to investigate:1.) How spatial obstacles change the distribution of genes that appear at a particular place on a chromosome populations of invading organisms. Of particular interest is gaining insight into how environmental inhomogeneities can shape not only the boundaries at front of a population of invading bacteria but also the genetic structure of the bacteria. This research has potential to contribute to understanding the evolution of resistance of bacteria to antibiotics, as when opportunistic pathogens such as Pseudomonas aeruginosa invade catheters connected to hospitalized patients.2.) How mechanical properties of very thin shells are affected by temperature. This builds on the observation that fluctuations that arise with increasing temperature lead to unusual mechanical properties that describe distortions of a sheet over long distances. The PI aims to understand what happens when the sheet is rolled in to a thin spherical shell. This research has potential to contribute to developing strategies for the delivery of drugs to affected areas of the body, as well as having implications for mechanical systems assembled on scales 1000 times or so smaller than the diameter of a human hair.3.) Networks that describe neural development in animals and humans, and in particular how loss of connections among neurons and the strengthening and weakening of neural connections lead to neural circuits learning various functions.The project will contribute to the training of students and postodocs in modern theoretical methods on problems with impact across disciplinary boundaries.TECHNICAL SUMMARYThis award will support theoretical research and education in the development and application of statistical physics methods to diverse problems in materials science and biophysics. The PI will tackle problems that challenge theory and lead to intriguing confrontations with experiments. The issues addressed include spatial population genetics near obstacles and constrictions, the soft condensed matter physics of thin thermalized shells and the theory of the eigenfunctions and eigenvalues that control the nonlinear dynamics of directed localization in sparse networks with spatial randomness. Nonequilibrium statistical dynamics and population genetics that incorporate genetic drift, mutations, migrations, and competition and cooperation have played a crucial role in the evolutionary history of many species, in particular on solid surfaces. Examples include the migrations of invasive species, or bacterial invasions of animal tissue. Using the tools of nonequilibrium statistical dynamics and population genetics the PI will examine how these phenomena affect genetic lineages in spatial media containing obstacles. Because biological organisms do not typically grow up in well-mixed test tubes or featureless Petri dishes, it is important to understand how they behave in the presence of environmental inhomogeneities. The PI's research on thermalized shells builds on the "extreme mechanics" of thin plates and shells, characterized by the highly nonlinear Foeppl - von Karman equations. The background curvature of thermally excited spherical shells presents new challenges relative to flat plates, which will be addressed by generalizing graphical summation and renormalization group methods that have proven useful for sheet polymers. Finally, the project will investigate directed localization and the associated nonequilibrium dynamics in strongly non-Hermitian matrices (involving both excitatory and inhibitory connections) that arise naturally in simple models of interacting ecosystems and in sparse neural networks. The PI's theoretical research will determine how the intricate fractal eigenvalue spectrum that controls the spontaneous activity and induced response changes with an increasing ratio of inhibitory to excitatory connections and with a variable bias for the transfer of information in a particular direction. Strongly interdisciplinary by nature, the research could provide insights into controlling human pathogen invasions, the development of drug delivery strategies, and human and animal neural development. In addition, the project will contribute to the training of students and postodocs in modern theoretical methods with a wide area of applicability.

非技术摘要这一奖项支持理论研究和教育，以利用统计物理学的力量来深入了解生物学，物理学和材料科学界面的复杂系统。该方法将跨学科边界的材料和材料相关现象的理解应用于具有生物学启发的问题，对应用具有潜在影响。该项目包含三个主要旨在调查的主要目的：1。）空间障碍如何改变在入侵生物体染色体种群上特定位置出现的基因的分布。特别有趣的是，人们深入了解环境不均匀性如何不仅可以塑造入侵细菌的人群前面的边界，还可以塑造细菌的遗传结构。这项研究有可能有助于理解细菌对抗生素的耐药性的演变，就像机会性病原体（如铜绿假单胞菌）入侵与住院患者相关的导管时。2。这是基于观察到的观察，即随着温度升高而引起的波动会导致异常的机械性能，这些机械性能描述了长距离板的扭曲。 PI的目的是了解将纸卷成薄的球形外壳时会发生什么。这项研究有可能有助于制定向人体受影响区域传递药物的策略，并且对与人头发直径小1000倍左右的机械系统产生影响。3。描述动物和人类的神经发育，特别是神经元之间的联系丧失以及神经联系的加强和弱化导致神经回路学习各种功能。该项目将有助于在现代理论方法中培训学生和验证后的问题。跨学科边界的影响。技术摘要奖将支持理论研究和教育，以开发和应用统计物理方法在材料科学和生物物理学中的各种问题上的发展和应用。 PI将解决挑战理论的问题，并导致与实验的吸引力。所解决的问题包括近乎障碍和收缩的空间遗传学，薄热壳的软凝结物理学以及控制稀疏网络中定位的非线性定位动态的特征函数和特征值的理论。融合了遗传漂移，突变，迁移以及竞争与合作的非平衡统计动力学和种群遗传学在许多物种的进化史上，尤其是在固体表面上起着至关重要的作用。例子包括入侵物种的迁移或动物组织的细菌入侵。使用非平衡统计动力学和种群遗传学的工具，PI将研究这些现象如何影响含有障碍的空间培养基中的遗传谱系。由于生物生物通常不会在混合良好的测试管或无特征的培养皿中长大，因此重要的是要了解它们在存在环境不均匀性的情况下的行为。 PI对热壳的研究建立在薄板和壳的“极端力学”上，其特征是高度非线性的绒毛-Von Karman方程。热激发球形壳的背景曲率相对于平板提出了新的挑战，这些挑战将通过概括图形求和和重新归一化的方法来解决，这些方法已证明对薄板聚合物有用。最后，该项目将调查在强烈的非热矩阵（涉及兴奋性和抑制性连接）中的定向定位和相关的非平衡动力学，这些动力在简单的相互作用生态系统和稀疏神经网络的简单模型中自然而然地出现。 PI的理论研究将决定如何控制自发活性并诱导响应变化，而抑制性与兴奋性连接的比率增加，并且对于特定方向传递信息的偏差，如何控制自发活性和诱导的响应变化。 这项研究本质上是强烈的跨学科，可以为控制人类病原体入侵，药物输送策略以及人类和动物神经发育提供见解。此外，该项目将有助于在现代理论方法中培训学生和博士后，并具有广泛的适用性。