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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
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SEQUENCE:0
UID:UW-Physics-Event-3273
DTSTART:20140205T220000Z
DURATION:PT1H0M0S
DTSTAMP:20260419T194030Z
LAST-MODIFIED:20140128T165926Z
LOCATION:5280 Chamberlin Hall
SUMMARY:From colloids to bacteria: anisotropy in self-organizing syste
 ms at the mesoscopic scale\, Faculty Candidate Seminar\, Kun Zhao\, UC
 LA
DESCRIPTION:Many complex mesoscopic systems\, ranging from synthetic c
 olloids to active biological cells\, exhibit a rich variety of pattern
 -forming behavior. In this talk\, I will show you how anisotropy in tw
 o model systems\, anisotropic shaped colloids and bacterial communitie
 s\, affect complex pattern formation. During the directed self-assembl
 y of colloidal systems\, shape anisotropy can greatly influence result
 ing structures. We have developed a technique called roughness control
 led depletion attraction which allows us to probe the phase space of 2
 D Brownian systems for a variety of anisotropic shapes such as triangl
 es\, squares\, and other polygons. We have discovered several unantici
 pated effects\, such as local chiral symmetry breaking in a triatic li
 quid crystal phase of uniform triangles. Anisotropy also plays a large
  role in the formation of bacterial communities called biofilms. Biofi
 lms are a major human health hazard as well as being an impediment in 
 many industrial and medical settings. By using condensed matter techni
 ques\, we present for the first time the dynamics of colony formation 
 at early stages of biofilm development for Pseudomonas aeruginosa. We 
 found that Pseudomonas aeruginosa does not follow an isotropic random 
 walk as commonly assumed\, but instead obeys a new form of polysacchar
 ide-guided dynamics such that the distribution of surface visitation f
 ollows a power law. This power low behavior may benefit bacteria socia
 l organization during biofilm formation.
URL:https://www.physics.wisc.edu/events/?id=3273
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