Research Initiation Award: Thermodynamic Phase Separation in a Living, Active Matter System

研究启动奖为历史悠久的黑人学院和大学的教职员工提供支持，他们正在建立一个研究项目。预计该奖项有助于进一步提高教师的研究能力和有效性，改善其所在机构的研究和教学，并让本科生参与研究经验。授予北卡罗来纳农业和技术州立大学的奖项可能在许多领域产生更广泛的社会影响。该项目旨在研究活动物质系统的动力学。这项研究跨越了数学、物理和生物学领域。本科生将获得研究经验，研究将整合到许多生物物理学课程中。该项目还将有助于该大学生物物理学专业的发展。与统计力学研究中传统上讨论的系综不同，活性物质系统由消耗能量并自我推进的物体组成，因此永远不会处于平衡状态。基于粘弹性流体中公牛精子集体动力学的发现，该项目专注于利用实验来量化和理解活性物质系统中相分离的现象学。该项目的主要目标是绘制簇状相和孤立相的共存曲线。这项研究将通过两种方法来实现：一种是基于“压力”的方法，它包括建立一个微流控装置来增加细胞密度；另一种是基于“温度”的方法，在这种方法中，通过改变流体性质来调节排列和随机因子的相对强度。该项目的发现将回答基本的热力学问题，例如如何量化生命活动物质系统中的压力或温度等参数，以及如何建立等价的状态方程。此外，由于哺乳动物雌性生殖道中自然存在粘弹性流体，该项目还将有助于了解精子运动的调节和机制。这些结果提供了潜在的基础科学知识，可以用来改善畜牧业。

Research Initiation Awards provide support for faculty at Historically Black Colleges and Universities who are building a research program. It is expected that the award helps to further the faculty member's research capability and effectiveness, improves research and teaching at his home institution, and involves undergraduate students in research experiences. The award to North Carolina Agricultural and Technical State University has potential broader and societal impact in a number of areas. The project seeks to investigate the dynamics of active matter systems. The research crosses the fields of mathematics, physics, and biology. Undergraduate students will gain research experiences and the research will be integrated in a number of biophysics courses. The project will also contribute to the development of a Biological Physics Concentration at the university.Unlike ensembles traditionally discussed in Statistical Mechanics research, active matter systems consist of objects that consume energy and propel themselves, and thus are never in equilibrium. Building on the discovery of bull sperm collective dynamics in viscoelastic fluids, this project focuses on using experiments to quantify and understand the phenomenology of phase separation in active matter systems. The primary objective of this project is to map out the coexistence curve of clustered and isolated phases. The research goal will be approached by two methods: a "pressure" based method that involves building a microfluidic device to increase cell density, and a "temperature" based method, in which the relative strengths of alignment and randomizing factors are tuned by changing fluid properties. Findings from this project will answer fundamental thermodynamics questions, such as how to quantify parameters like pressure or temperature in a living active matter system, and how to formulate an equivalent equation of state. Moreover, since viscoelastic fluids are naturally present in the mammalian female reproductive tract, this project would also help to understand the regulation and mechanisms of sperm movement. The results provide underlying basic science knowledge that could potentially be used to improve animal husbandry.