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A.B, 1974, Harvard College. Ph.D., 1978, Princeton University. Research Assistant and Postdoctoral Research Associate, University of Virginia, Charlottesville, 1977-82. Assistant Professor, Physics, Cornell University, 1982-88; Associate Professor, Physics, Cornell University, 1988-present. Visiting Professor, Physics, University of Bristol, England, 1991. Member, American Physical Society.

Research Areas

Experimental biological physics and liquid physics

Current Research

Our group's interests have been focused on the behavior of liquid, colloidal and living systems on length scales that are much greater than atomic. Currently, our main effort has been directed at understanding the social behavior of microbes. We have particular interest in the remarkable transition from unicellular to multicellular life that the organism Dictyostelium discoideum ("Dicty") makes in reaction to the removal of its food supply. Our recent work by graduate researchers Albert Bae in collaboration with Eberhard Bodenschatz (Cornell Physics and Max Planck Inst., Gottingen, Germany) and his group and colleagues at the University of California San Diego has exploited microfluidic technology to measure key elements of the signal-response system necessary for the transition to social life. Specifically, we have been studying the movement of individual amoebae in response to a static gradient of a signaling molecule (L. Song, et al. Eur. Jour. Cell Bio., v. 85, p. 981 (2006)). We are currently preparing a follow-up experiment to study few molecule effects in the direction sensing appartatus with graduate researcher Elijah Bogart and undergraduate researchers Surin Mong ad Eitan Neidich.

In other work undergraduate researcher Ryan Monaghan and graduate researchers Kayvon Daie and Albert Bae have been altering the signaling medium through which extracellular messages may pass and discovering the consequent changes in the means by which Dicty manage to congregate. These perturbations have exploited novel wetting and microfluidic environments. We have also developed theory to match these observations by considering the problem of synchronizing many oscillators via long range chemical signaling.

With graduate researchers Elijan Bogart, Kayvon Daie and Albert Bae and undergraduate researchers Xiao-Qiao Zhou, Amrish Deshmukh, and Sharon Lau we have been exploring possible collective effects in microbe growth. Through bulk suspension cultures and microfluidic flow systems they have be discovering that the decision as to whether a cell colony has sufficient density to trigger the growth cycle in individual cells does not rely on chemical messages passed through the growth media as expected. Rather we have been giving a semiquantitative account of our measurements by means of a theory that views the switch of a cell into the growth state as the result of collisions between cells. (C. Franck, et al. Phys. Rev. E v. 77, p. 0141905 (2008)). Our most recent work has explored the diversity of growth behaviors possible in this system and has been developing theory to match by considering noise and cell adhesion effects. Our work relies heavily on genetically modified organisms, microscopy (including confocal) augmented by digital image processing and macroscale and microscale reactor biotechnology. A subtheme of our effort is to uncover the quanititative basis of communication and computation in living matter.

Finally, with undergraduate researcher Andrew Hirschl, we have been developing apparatus and computational tools to explore three body correlation functions in colloidal liquids through video holography. Our aim is to test a fundamental assumption behind liquid state theory.