CAREER: Standing Out in a Crowd, Neutron Based Methods to Study Molecular

职业：在人群中脱颖而出，基于中子的分子研究方法

• 批准号: 2146264
• 负责人: Jonathan Nickels
• 金额: $ 50.4万
• 依托单位: University of Cincinnati Main Campus
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-05-01 至 2027-04-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2146264&HistoricalAwards=false
• 关键词: CAREER; Standing; Out; Crowd; Neutron

Neutron scattering is a powerful and elegant experimental technique. Vital in studying hydrogen-rich biological and polymeric materials, magnetism, imaging, and exploring exotic states of matter; neutrons have clear role in the national scientific repertoire. This project will develop novel neutron scattering experiments – leveraging the unique advantages of neutrons to address fundamental questions in molecular transport emerging from crowded aqueous environments. This project will combine these research activities with the creation of a teaching module within the mass transport course for chemical engineers using neutron scattering to demonstrate the molecular origins of diffusion in simple liquids; along with the development of a new undergraduate course focused on "Large Scale Science". The overwhelming majority of neutron science in the US is conducted at large facilities, cementing the notion that some science simply requires shared national facilities. Neutron sources are significant national investments, the "Large Scale Science" class will focus on how neutron scattering facilities and other large scale scientific facilities come to be, what they accomplish, how they operate, and finally, how they fit into the national and international scientific landscape. Students will visit national facilities and representative leaders to learn more about the process and priorities of large-scale science. Molecularly crowded environments are structurally complex and dynamic. Molecular transport via diffusion is often observed to become anomalous within these environments. This means that the mean square displacement (MSD) exhibits a weaker time dependence than the typical Brownian diffusion mechanism. Solutes may become trapped for arbitrarily long residence times, demonstrate highly correlated relaxation times, and/or coupled dynamics to the local solvent. Neutrons offer unique strategies to probe such questions when combined with contrast matching and scattering cross-section manipulation strategies. Selective deuteration is the enabling methodology for neutron scattering experiments in this project. Deuteration will be deployed in several ways to highlight the solute molecule motions in crowded environment as if it were a single particle in dilute solution. This will isolate the single molecule contribution to anomalous diffusion. This can be compared then to the local relaxations of the solvent or other medium, such as a hydrogel, to isolate localized hydrodynamic effects versus collective effects. Structural characterizations of the same systems will inform our theoretical understanding of the ergodicity of the system, the violations of which, can explain some of the anomalous phenomena through better understanding of the flaws in the assumed structural and dynamical distributions at the heart of existing models.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

中子散射是一种强大而优雅的实验技术。在研究富氢生物和聚合材料，磁性，成像和探索物质的奇异状态至关重要；中子在国家科学宝库中有着明确的地位。该项目将开发新的中子散射实验-利用中子的独特优势来解决分子在拥挤的水环境中传输的基本问题。本项目将结合这些研究活动，在化学工程师的质量传输课程中创建一个教学模块，使用中子散射来演示简单液体中扩散的分子起源；同时开设了以“大尺度科学”为重点的本科新课程。在美国，绝大多数中子科学都是在大型设施中进行的，这巩固了一些科学只需要共享国家设施的观念。中子源是重大的国家投资，“大规模科学”课程将重点关注中子散射设施和其他大规模科学设施是如何形成的，它们完成了什么，它们如何运作，以及它们如何适应国家和国际科学格局。学生将参观国家设施和代表领导人，以了解更多关于大规模科学的过程和优先事项。分子密集的环境在结构上是复杂和动态的。在这些环境中，通过扩散的分子运输经常被观察到变得异常。这意味着均方位移（MSD）表现出比典型的布朗扩散机制更弱的时间依赖性。溶质可以被困住任意长的停留时间，表现出高度相关的松弛时间，和/或与局部溶剂耦合的动力学。中子与对比匹配和散射截面操作策略相结合，为探索这些问题提供了独特的策略。选择性氘化是本项目中子散射实验的可行方法。氘化将以几种方式部署，以突出溶质分子在拥挤环境中的运动，就好像它是稀释溶液中的单个粒子一样。这将分离出单个分子对异常扩散的贡献。这可以与溶剂或其他介质（如水凝胶）的局部弛豫进行比较，以分离局部流体动力学效应和集体效应。相同系统的结构特征将告知我们对系统遍历性的理论理解，该系统的违反可以通过更好地理解现有模型核心假设的结构和动力学分布中的缺陷来解释一些异常现象。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Amphiphilic Co-Solvents Modulate the Structure of Membrane Domains

• DOI: 10.1021/acssuschemeng.2c06876
• 发表时间: 2023-01
• 期刊: ACS Sustainable Chemistry & Engineering
• 作者: Luoxi Tan;H. L. Scott;M. Smith;S. Pingali;H. O’Neill;J. Morrell-Falvey;J. Katsaras;Jeremy C. Smith-Jer