Scroll Wave Dynamics in Heterogeneous Reaction-Diffusion Systems

该奖项由化学系化学结构、动力学和机制项目资助，由佛罗里达州立大学（Florida State University， FSU）教授奥利弗·斯坦伯克（Oliver Steinbock）领导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。这些远离平衡的系统是21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，并产生了人们通常只在生物学中才能找到的信息传递模式。该项目侧重于三维可激介质中未被充分研究的过程，特别是旋转涡旋波。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尾随“难熔区”形成的。主要目标是建立三维可激系统中涡钉钉和涡解钉钉的完整描述。一个重要的例子是区分真正固定在小的非均质和仅仅表面终止旋涡的旋转骨干。实验将包括弱激发、弯曲和移动的异质性，这些异质性应该允许涡旋波的主动重新定位和重塑。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模式稳定性，该阈值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。另一个目标是利用外部控制的电场和温度梯度，演示和分析bz -凝胶体系中涡旋环的非均质解除。该项目将测试一个假设，即可以通过相对于固定、环形锚或径向扩展的滚动环倾斜来解除固定。这些研究将由运动学建模工作和三维反应扩散模型的计算研究来补充。这个项目下的许多化学研究都是由生命系统的自组织驱动的。一个引人注目的例子是人类心脏中电子模式的运动，它协调了这个重要器官健康或紊乱的泵动作。旋转的旋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重复性实验已经并将揭示对这些状态的重要见解。Steinbock教授的研究团队将专门研究这些漩涡是如何被不太活跃的区域改变、重塑并可能稳定下来的。在心脏的情况下，这些区域对应于由创伤事件（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领导作用的指导计划。具体活动包括为FSU的全球教育推广计划和YouTube制作视频。此外，Steinbock教授还将参加FSU针对一年级学生的荣誉研究计划，并为当地大学预科学生举办“周六上午物理”系列讲座。

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.