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Transport across microscopic channels: diffusion pumping
Colloquium| Speaker: | Thomas Chou, MIT |
| Location: | 693 Kerr |
| Start time: | Thu, Feb 11 1999, 4:10PM |
Description
Living cells need to exchange nutrients, water, and
various other molecules with their environment.
Transmembrane structures have evolved to facilitate transport
of desired molecules. A similar system is molecular
transport through zeolites, which are also comprised of
molecular-sized channels. On these scales, continuum
descriptions do not capture the nonlinear behavior resulting
from finite-sized molecular interactions. A simple
one-dimensional lattice model obeying exclusion statistics
is used to describe transport across microscopic single-file
channels. The finite-sized effects lead to nonlinear coupling between
multispecies flow resulting in interesting pumping across
molecular pores. The results may qualitatively explain osmosis
measurements, propose possible mechanisms for bioenergetic
coupling, as well as suggest more systematic experiments.
Related ongoing work on collective particle transport will also be
outlined.