From: E.braswell <BRASS@UCONNVM.UCONN.EDU>
  To  : rasmb@alpha.bbri.org
  Date: Tue, 07 Dec 99 09:31:29 EST

Folks, in regard to Borries suggestion of shaking up and doing an
experiment over.  This can be a dangerous practice especially for velocity
runs.   Many systems self-associates at high concentrations
(at the bottom of the cell) to materials that have a low off rate-
you may change the nature of the high molecular species you observe.
In some cases I have seen a gel-like material form on the
bottom of the cell which was extremely hard to redisperse.  That is one
reason why we do equilibrium runs at the lowest speed first and then
increase the speed after each equilibrium is attained.    Emory

Emory H. Braswell
Professor of Biophysics and Head,
National Analytical Ultracentrifugation Facility
U-149
University of Connecticut
STORRS, CT 06269-3149
TEL 860 486 5032
FAX         5005
E.BRASWELL@UCONN.EDU