Abstract: 
Microbes inhabit planet earth over billions of years and have adapted to diverse physical environments, particularly at or near fluid boundaries. We study the swimming motility of uni-flagellated bacteria Caulobacter crescentus and Pseudomonas aeruginosa. Our studies provide a comprehensive account of the characteristic swimming trajectories and accumulation of C. crescentus swarmer cells near solid surfaces, and their trapped motion at the air/water interface. Besides swimming, P. aeruginosa and many other species of bacteria display swarming motility, an impressive form of collective migration, as a growing population of bacteria spreads over a solid surface.  Our study reveals fundamental fluid physics and interfacial mechanisms that account for a rich variety of patterns expanding bacterial colonies develop, including fingerlike protrusions, expanding wave-fronts, and dynamic droplets. By elucidating physical mechanisms diverse species of bacteria have discovered, adopted, and employed through the course of evolution, we hope to use these insights for environmental and biomedical applications.

​

Biography: 
Professor Jay X. Tang received his BS in physics from Peking University in 1987, and came to the US for graduate study through the China and the US Physics Examination and Application (CUSPEA) program established by Professor TD Lee, a Nobel Laureate in Physics. Prof. Tang received his PhD in Physics from Brandeis University. After postdoctoral training at Harvard Medical School, he became an assistant professor of physics at Indiana University in 1999. Since 2003 he has been on the faculty of Brown University. He is currently professor of physics and engineering. Prof. Tang's research area is experimental biophysics, with topics covering morphology, pattern formation, cell mechanics, and motility of cells. Professor Tang has published close to 100 original research papers and received several research awards from National Science Foundation and National Institute of Health. Prof. Tang is a Fellow of the American Physical Society. He is also a member of the Biophysical Society. He also serves on the board of the Peking University Alumni Association of New England, Math and Science Society for Youth, New England Chinese Bridge Association, etc.