题 目：Bacteria near surfaces
Abstract：Flagellated bacteria such as E. coli swim along circular trajectories adjacent to surfaces. For instance, the non-tumbling mutant of E. coli swims in a clockwise trajectory near a solid boundary  and a counterclockwise trajectory near a liquid-air interface . We develop a bacterium model  with a spherocylindrical body propelled by a bundle of rotating helical flagella, which can quantitatively reproduce the experimental results of swimming E. coli. We employ mesoscale hydrodynamics simulations  of such model bacteria to investigate the near-surface swimming behaviour. Combining with theoretical calculations of the hydrodynamic forces on the bacteria, we show how the curvature of radius of the circular trajectory depends quantitatively on the slip length of the surface. We find that the cell is sensitive to nanoscale changes in the surface slip length . The results are employed to propose a novel approach to directing bacterial motion on striped surfaces with different slip lengths, which implies anisotropic transport of bacteria as demonstrated from simulations of active Brownian rods.
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Short Bio：胡晶磊教授毕业于南京大学，2008-2014年分别在德国Max-Planck Institute of Colloids & Interfaces, Juelich Research Center从事博士后研究，2014年加入南京大学。主要从事Microswimmers, 大肠杆菌等动力学行为研究。