<html aria-label="message body"><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body style="overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><div>Dear Soft Matter & Complex Systems Colleagues and Friends,</div><div><br></div><div>On Friday 20 March 2026 at 9:30 AM at the UW Faculty of Physics (Pasteura 5, Warsaw; room 1.40) we are hosting a seminar, during which</div><div><br></div><div><b>Rafał Błaszkiewicz</b> (FUW)</div><div><br></div><div>will give a talk</div><div><br></div><div><b>Unsteady Effects in Cilia-Mediated Transport and Microscale Mixing</b></div><div><br></div><div><b>Abstract</b></div><div><br></div><div>Cilia are key drivers of fluid transport in biological systems, from single-celled organisms to human tissues. Traditional models often treat ciliary flows as steady, yet ciliary beating is inherently unsteady, generating flows that evolve on timescales comparable to viscous diffusion.</div><div><br></div><div>In this work, we use a time-dependent linear Stokes framework with Green’s functions and memory kernels to model flows generated by individual and coordinated cilia motion, represented by point-like “Pufflets.” Combining theory, simulations, and experiments, we examine how unsteady actuation affects particle trajectories and flow structures.</div><div><br></div><div>Our results show that unsteady effects can modify transport pathways and influence mixing at the microscale, particularly when multiple cilia interact. These findings highlight important differences between steady and unsteady Stokes flows and provide insight into the mechanisms underlying cilia-mediated fluid transport.</div><div><br></div><div>Co-authors of the work: Margot Young², Albane Théry², Talia Becker Calazans², Arnold J.T.M. Mathijssen², Maciej Lisicki¹</div><div>¹University of Warsaw, Warsaw, Poland; ²University of Pennsylvania, Philadelphia, USA</div><div><br></div><div>The full study is available at: https://doi.org/10.48550/arXiv.2603.11020</div><div><br></div><div>We warmly welcome everyone to attend the talk and the Soft Matter Coffee Break after the seminar, held in room 2.63 (2nd floor).</div><div><br></div><div>Maria Ekiel-Jeżewska</div><div>Maciej Lisicki</div><div>Piotr Szymczak</div><div>Panagiotis Theodorakis</div>
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