Active Flows and Deformable Surfaces in Development

致密可变形活性粒子的粗粒化

Coarse-graining dense, deformable active particles

针对汇合可变形活性粒子材料的建模问题，对紧密堆积可变形椭圆粒子模型粗粒化推导连续介质方程，揭示相互作用与活性流动的影响，结果与多相场模拟吻合，搭建细胞模型与活性物质连续理论的桥梁。

Morphology of active deformable 3D droplets

We numerically investigate the morphology and disclination line dynamics of active nematic droplets in three dimensions. Although our model only incorporates the simplest possible form of achiral active stress, active nematic droplets display an unprecedented range of complex morphologies. For extensile activity finger-like protrusions grow at points where disclination lines intersect the droplet surface. For contractile activity, however, the activity field drives cup-shaped droplet invagination, run-and-tumble motion or the formation of surface wrinkles. This diversity of behaviour is explai…

手性活性布朗粒子驱动的可变形囊泡输运

Transport of Deformable Vesicles Driven by Chiral Active Brownian Particles

本研究通过数值模拟和解析理论，揭示了手性活性粒子填充的可变形囊泡中，手性驱动旋转且存在最优手性，并建立了普适标度关系。

Solid-Liquid Transition of Deformable and Overlapping Active Particles

Experiments and theory have shown that cell monolayers and epithelial tissues exhibit solid-liquid and glass-liquid transitions. These transitions are biologically relevant to our understanding of embryonic development, wound healing, and cancer. Current models typically consider purely two-dimensional monolayers with no overlaps between neighboring cells. In reality, overlaps are important, and they may be precursors of cell extrusion -- a key biophysical process to maintain homeostasis in epithelial tissues. Here, we use a multi-phase field model to study the solid-liquid transition in a con…

Computational modeling of active deformable membranes embedded in 3D flows

Active gel theory has recently been very successful in describing biologically active materials such as actin filaments or moving bacteria in temporally fixed and simple geometries such as cubes or spheres. Here we develop a computational algorithm to compute the dynamic evolution of an arbitrarily shaped, deformable thin membrane of active material embedded in a 3D flowing liquid. For this, our algorithm combines active gel theory with the classical theory of thin elastic shells. To compute the actual forces resulting from active stresses, we apply a parabolic fitting procedure to the triangu…

活性向列相对可变形物体或边界的响应：弹性形变与锚定诱导流动

Active nematic response to a deformable body or boundary: elastic deformations and anchoring-induced flow

本文用复变量方法解析二维活性向列相中线弹性物体的流动、指向矢、牵引力与形变，揭示活性应力和锚定条件诱导的效应及应力测量新思路。