Scroll Wave Dynamics in Heterogeneous Reaction-Diffusion Systems

非均相反应扩散系统中的涡旋波动力学

• 批准号: 1213259
• 负责人: Oliver Steinbock
• 金额: $ 39.52万
• 依托单位: Florida State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-15 至 2016-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1213259&HistoricalAwards=false
• 关键词: Scroll; Wave; Dynamics; Heterogeneous; Reaction

In this award, funded by the Chemical Structure, Dynamics and Mechanisms Program of the Division of Chemistry, the research group of Professor Oliver Steinbock (Florida State University, FSU) will investigate self-organizing wave patterns in autocatalytic reaction-diffusion systems. These far-from-equilibrium systems are a treasure trove for 21st century science. They create intricate regulatory networks, exhibit fascinating dynamics, and generate information-relaying patterns that one typically expects to find only in biology. The project focuses on understudied processes in three-dimensional excitable media and specifically on rotating scroll waves. These dissipative structures are formed by propagating regions of autocatalytic activity and trailing "refractory zones" of high inhibitor concentration. The primary goal is to establish a complete description of vortex pinning and vortex unpinning in three-dimensional excitable systems. An important example is the distinction between true pinning to small heterogeneities and mere surface termination of the vortices' rotation backbone. Experiments will include weakly excitable, curved, and moving heterogeneities that should allow the active repositioning and reshaping of scroll waves. These challenging studies can be pursued using photochemical methods and/or computer-controlled motion of solid objects. The latter approach will induce fluid flow in the reactive solution but should not affect pattern stability below threshold values that the will be characterized systematically during the project. If successful, these studies will also provide a novel approach to chemo-hydrodynamic systems. Another goal is to demonstrate and analyze the unpinning of scroll rings from heterogeneities in BZ-gel systems using externally controlled electric fields and temperature gradients. The project will test a hypothesis that unpinning can proceed via tilting of the scroll ring relative to the pinning, torus-shaped anchor or alternatively via radial expansion. These investigations will be complemented by kinematic modeling efforts and computational studies of three-dimensional reaction-diffusion models. Much of the chemical research under this project is motivated by the self-organization of living systems. A striking example is the motion of electrical patterns in the human heart that orchestrate the healthy or disturbed pump action of this vital organ. Spinning, vortex-like states have been linked to tachycardia and ventricular fibrillation with the latter being among the leading causes of death for Americans. Highly reproducible experiments with simpler chemical systems have and will reveal important insights into these states. The research team around Prof. Steinbock will specifically investigate how such vortices are changed, reshaped, and possibly stabilized by less active regions. In the context of the heart such regions correspond to scar tissue caused by traumatic events such as heart attacks. This multi-faceted research is also ideally suited for the modern training of undergraduate, graduate, and postdoctoral students. Furthermore Prof. Steinbock will continue his firm commitment to foster underrepresented groups and participate in mentoring programs that aim to increase their leadership roles in research and academia. Specific activities include the production of videos for FSU's Global Educational Outreach Program and YouTube. In addition, Prof. Steinbock will participate in FSU's Honors Research Program for first-year students and contribute to the "Saturday Morning Physics" lecture series for local pre-college students.

在这个奖项中，由化学系的化学结构，动力学和机制计划资助，奥利弗斯坦博克教授（佛罗里达州立大学，FSU）的研究小组将研究自催化反应扩散系统中的自组织波模式。这些远离平衡态的系统是21世纪世纪科学的宝库。 它们创造了复杂的调控网络，展现出迷人的动态，并产生了人们通常认为只有在生物学中才能找到的信息传递模式。 该项目的重点是在三维可激发介质，特别是在旋转涡卷波研究不足的过程。 这些耗散结构是由自催化活性的传播区域和高抑制剂浓度的拖尾“耐火区”形成的。 主要目的是建立一个完整的描述涡钉扎和涡unpinning在三维可激发系统。 一个重要的例子是真正的钉扎到小的不均匀性和纯粹的表面终止的旋涡的旋转骨干之间的区别。 实验将包括弱兴奋，弯曲，移动的异质性，应该允许积极重新定位和重塑的滚动波。 这些具有挑战性的研究可以使用光化学方法和/或计算机控制的固体物体运动来进行。 后一种方法将在反应性溶液中诱导流体流动，但不应影响低于阈值的井网稳定性，这将在项目期间系统地表征。 如果成功，这些研究也将为化学流体动力学系统提供一种新的方法。 另一个目标是展示和分析的unpinning涡卷环从BZ-凝胶系统中的异质性，使用外部控制的电场和温度梯度。 该项目将测试一个假设，即可以通过涡旋环相对于销轴、环形锚的倾斜或替代地通过径向膨胀来进行解销。 这些调查将补充三维反应扩散模型的运动学建模工作和计算研究。该项目下的大部分化学研究都是由生命系统的自组织所推动的。一个突出的例子是人类心脏中的电模式的运动，它协调了这个重要器官的健康或受干扰的泵送动作。 旋转的漩涡状状态与心动过速和心室颤动有关，后者是美国人死亡的主要原因之一。 用更简单的化学系统进行的高度可重复的实验已经并将揭示对这些状态的重要见解。Steinbock教授周围的研究团队将专门研究这些漩涡如何被不太活跃的区域改变，重塑，并可能稳定。在心脏的情况下，这些区域对应于由创伤事件（诸如心脏病发作）引起的疤痕组织。 这种多方面的研究也非常适合本科生，研究生和博士后学生的现代培训。 此外，Steinbock教授将继续坚定地致力于培养代表性不足的群体，并参与旨在提高他们在研究和学术界的领导作用的指导计划。 具体活动包括为前苏联的全球教育推广方案和YouTube制作视频。 此外，Steinbock教授还将参加FSU为一年级学生举办的荣誉研究计划，并为当地大学预科学生举办的“周六上午物理”系列讲座做出贡献。