International Research Fellowship Program: Shear-perturbed Polymer Structure and Dynamics through NMR Spectroscopy and Rheo-NMR

国际研究奖学金计划使美国科学家和工程师能够在国外进行9至24个月的研究。该计划的奖项提供了联合研究的机会，并利用国外独特或互补的设施、专业知识和实验条件。该奖项将支持詹妮弗·R·布朗博士与新西兰惠灵顿大学的保罗·卡拉汉博士合作18个月的研究奖学金。核磁共振(核磁共振)光谱与Rheo-NMR相结合，被用于研究响应机械变形的聚合物分子的有序性和动力学。核磁共振技术具有独特的能力，通过空间分辨率将宏观材料的响应与通过光谱技术的微观分子现象联系起来。机械响应的分子基础最近引起了人们的兴趣，因为在生物、食品和材料加工、石油回收和生物技术应用中存在许多复杂的流体。Rheo-核磁共振的使用为研究此类体系中的分子动力学提供了一个独特的视角，因为剪切池包含在核磁共振光谱仪中，并且样品可以在运动状态下进行研究。使用高分辨率窄间隙圆柱形Couette剪切池，具有足够高的剪切速率，应中断氢键。对于缔合碳水化合物透明质酸，~(13)C核磁共振证实了剪切力对构象的影响，这有力地表明在其他缔合多糖中也可以观察到类似的影响，这鼓励了流变学-核磁共振和光谱学在研究具有预先指定光谱的蛋白质(如胰岛素)方面的潜力。用核磁共振波谱技术研究剪切扰动的蛋白质和多糖，试图确定分子间相互作用的位置及其相关的反应速率。蛋白质分子动力学和结构的核磁共振研究有可能改进现代聚合物材料的设计和加工，例如创造出具有更好质地的食品或更好地了解重要的生物流体特性。由于蛋白质结构与功能有关，了解结构的流变效应可能产生的科学影响跨越了从生物学到化学和材料科学的各个领域。因此，拟议的研究具有高度跨学科的性质，增加了各领域的合作和交流。

0753559BrownThe International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support an eighteen month research fellowship by Dr. Jennifer R. Brown to work with Dr. Paul Callaghan at the University of Wellington in New Zealand.Nuclear Magnetic Resonance (NMR) spectroscopy, in combination with Rheo-NMR, is being used to study polymer molecular order and dynamics in response to mechanical deformation. NMR techniques have the unique ability to connect macroscopic material responses through spatial resolution to microscale molecular phenomena via spectroscopic techniques. The molecular basis for the mechanical response has been of recent interest since there are many complex fluids in biology, food and material processing, oil recovery and biotechnology applications. The use of Rheo-NMR offers a unique perspective in the investigation of the molecular dynamics in such systems, since the shear cell is contained within the NMR spectrometer and the sample may be studied while in motion. A high resolution narrow gap cylindrical Couette shear cell is used with the capacity for high enough shear rates that hydrogen bonds should be interrupted. For the associating carbohydrate hyaluronan, the influence of shear on conformation has been proven using 13C NMR, which strongly suggests that similar effects can be observed in other associating polysaccharides, and encourages the potential of Rheo-NMR and spectroscopy in investigating proteins with a pre-assigned spectra, such as insulin. This study of shear-perturbed proteins and polysaccharides with NMR spectroscopic techniques attempts to identify the sites responsible for inter-molecular interactions and their associated reaction rates. NMR studies of protein molecular dynamics and structure have the potential to improve the design and processing of modern polymeric materials, such as creating food with better texture or to better understand biologically important fluid properties. Since protein structure is related to function, the possible scientific impacts of understanding the rheological effect on structure spans fields ranging from biology to chemistry and materials science. The proposed research is therefore of a highly inter-disciplinary nature, which increases collaboration and communication across fields.