15 research outputs found
Shear-induced dynamics of polymeric globules at adsorbing homogeneous and inhomogeneous surfaces
Generic flow profiles induced by a beating cilium
We describe a multipole expansion for the low Reynolds number fluid flows
generated by a localized source embedded in a plane with a no-slip boundary
condition. It contains 3 independent terms that fall quadratically with the
distance and 6 terms that fall with the third power. Within this framework we
discuss the flows induced by a beating cilium described in different ways: a
small particle circling on an elliptical trajectory, a thin rod and a general
ciliary beating pattern. We identify the flow modes present based on the
symmetry properties of the ciliary beat.Comment: 12 pages, 6 figures, to appear in EPJ
Conformational dynamics and internal friction in homopolymer globules: equilibrium vs. non-equilibrium simulations
We study the conformational dynamics within homopolymer globules by solvent-implicit Brownian dynamics simulations. A strong dependence of the internal chain dynamics on the Lennard-Jones cohesion strength ε and the globule size N [subscript G] is observed. We find two distinct dynamical regimes: a liquid-like regime (for ε ε[subscript s] with slow internal dynamics. The cohesion strength ε[subscript s] of this freezing transition depends on N G . Equilibrium simulations, where we investigate the diffusional chain dynamics within the globule, are compared with non-equilibrium simulations, where we unfold the globule by pulling the chain ends with prescribed velocity (encompassing low enough velocities so that the linear-response, viscous regime is reached). From both simulation protocols we derive the internal viscosity within the globule. In the liquid-like regime the internal friction increases continuously with ε and scales extensive in N [subscript G] . This suggests an internal friction scenario where the entire chain (or an extensive fraction thereof) takes part in conformational reorganization of the globular structure.American Society for Engineering Education. National Defense Science and Engineering Graduate Fellowshi