Electrohydrodynamics of epithelial tissues by Niladri Sarkar скачать в хорошем качестве

Electrohydrodynamics of epithelial tissues by Niladri Sarkar

Seminar Electrohydrodynamics of epithelial tissues Speaker: Niladri Sarkar (Lorentz Institute for Theoretical Physics, Universiteit Leiden) Date: Tue, 07 January 2020, 14:00 to 15:30 Venue: Emmy Noether Seminar Room, ICTS Campus, Bangalore Abstract We study the dynamics of a thick polar epithelium subjected to the action of both an electric and a flow field in both planar and spherical geometry. We develop a generalized continuum hydrodynamic description and describe the tissue as a two component fluid system. The cells and the interstitial fluid are the two components and we keep all terms allowed by symmetry. In particular we keep track of the cell pumping activity for both solvent flow and electric current. We study the growth dynamics of a tissue slab, its steady states and obtain the dependence of the cell velocity, net cell division rate, and cell stress on the flow strength and the applied electric field. We find that finite thickness tissue slabs exist only in a restricted region of phase space and that relatively modest electric fields or imposed external flows can induce either proliferation or death. We also find that fluid pumping and active flexoelectricity is a contributor to lumen formation in spherical epithelium, and gives rise to interesting dynamics by the tissue after lumen nucleation. Table of Contents (powered by https://videoken.com) 0:00:00 Electrohydrodynamics of epithelial tissues 0:00:27 Epithelial tissues 0:01:08 Thick epithelial tissues 0:01:54 Characteristics of epithelial tissues 0:03:00 Dependence of tissue properties on applied stress 0:05:21 Dependence of cell division on applied electric field 0:06:25 Relevant questions for epithelial tissues 0:06:58 From discrete to continuum description.... 0:08:22 Outline 0:08:46 Hydrodynamics of tissues 0:10:26 Force Balance 0:11:37 Fluidization of tissue by cell division and death 0:14:18 Fluid pumping and ion transport 0:14:46 Constitutive equation for cell stress 0:20:11 Momentum exchange between cells and fluids 0:20:59 Electric current density 0:22:45 Boundary Conditions for a thick tissue slab 0:25:03 Thickness dynamics of the thick epithelium 0:28:08 Dynamics at positive surface growth velocity 0:29:07 Steady state profiles 0:30:22 Dynamics at negative surface growth velocity 0:32:55 Spheroid with a lumen 0:33:34 Boundary Conditions 0:34:21 Radii dynamics 0:34:38 Long time spheroid dynamics 0:36:24 Formation of lumen 0:39:11 Lumen formation 0:41:18 State diagram 0:42:20 Oscillations 0:43:05 Conclusions 0:43:43 Outlook 0:46:41 Acknowledgements 0:47:03 Thanks for your attention