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MathBio Mini-Talks
Mathematical Biology| Speaker: | Tim Lewis, Becca Thomases, Emmet Francis, UC Davis |
| Location: | Zoom |
| Start time: | Mon, Apr 26 2021, 2:10PM |
Tim Lewis, UC Davis
Title & Abstract: TBA
Emmet Francis, UC Davis
Title: Finite element modeling of axisymmetric immune cell spreading during phagocytosis
Abstract: White blood cells such as human neutrophils have the remarkable ability to engulf pathogens via the process of phagocytosis. This process requires the cell to undergo well-defined deformations, specifically by spreading over the pathogen surface until it is completely enveloped. Here, we present a computational model of axisymmetric spreading on a flat surface, which corresponds to the case of frustrated phagocytosis in which a pathogen is too large to be completely engulfed. We developed a minimalistic model in which the cell is represented as a body of highly viscous fluid surrounded by an elastic cortex. Upon specifying the forces acting on the cell boundary, we can solve for fluid flow within the cell and the resultant cell deformation over time using the finite element method. By comparing results from this model to results from our experiments with primary human neutrophils, we can infer critical information about boundary forces on the cell. For instance, we recently showed that modeling cell adhesion in phagocytosis using an attractive potential tends to overestimate the contribution of adhesion as a driving force; rather, spreading is driven by forces actively exerted by the cell, while adhesion mainly plays the role of providing local attachments to the surface to brace further spreading.
Becca Thomases, UC Davis
Title: Complex fluids in biology
Abstract: Non-Newtonian or complex fluids describe a wide class of materials from biological fluids like mucus and blood to everyday household products like shampoo and paint. There are many open questions in the study of such materials that involve deriving appropriate constitutive models, studying mathematical well-posedness of these systems, and improving numerical schemes for these models. There are also many problems in physics and biology where understanding motion of (or in) complex fluids is essential for understanding natural phenomena. Tools from mathematical analysis and computational simulations can shed light on these complex problems that are significant in many biological, environmental, and industrial applications. I will describe some current and open research problems in the field including recent work on modeling sperm swimming in viscoelastic fluids.