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Physics Colloquium: Arvind Gopinath (UCM) - "Memory, persistence of strain and loss of coherence in active motor-filament assemblies"

April 28, 2017 - 5:30pm

Title:   Memory, persistence of strain and loss of coherence in active motor-filament assemblies

Cross-linked flexible filaments interacting with molecular motors occur in natural and synthetic settings such as eukaryotic flagella, the cytoskeleton and motor assays. The deformation of these active composites when subject to strains - emergent or imposed - is determined by fluctuating motor forces, passive filament elasticity and structural constraints. What sets the length scale over which elastic deformations persist in such systems and controls the spatial coordination of collective dynamics? We address this fundamental question in the context of ordered composites comprised of cross-linked elastic filaments sheared by active motors. Combining results from mean field theory for a noiseless system with discrete simulations for noisy systems, we show that localized steady or oscillatory strains decay over lengths set by motor activity, shear stiffening and filament elasticity. Backbone extensibility, however weak, controls the transmission of mechanical information and sets a finite cutoff for spatially separated motor groups to stay synchronized. Our results generalize the notion of persistence in passive, Brownian filaments to active, cross-linked filaments.

 

Biography:

Dr. Gopinath obtained his Bachelor degree in Chemical Engineering from IIT, Bombay in 1993 and PhD in Chemical and Bio-molecular engineering from Cornell University in 2001. He then held post-doctoral positions at MIT and at Harvard followed by faculty positions at Indian Institute of Science (JNCASR) and A*Star, Singapore. He has more recently been a senior researcher at MIT, at Brandeis and at the Max-Planck Institute for Dynamical Systems (MPIDS), Germany. He is currently a scientist at the School of Engineering, UC Merced with research interests in mechanobiology, fertility, bio-computing and adaptive matter.

 

Every Friday 10:45-11:45 a.m., COB 267 (except as noted). Refreshments will be served from 10:30 - 10:45 a.m. Questions regarding the seminar series should be directed to Prof. Bin Liu