From: E.braswell <BRASS@UCONNVM.UConn.Edu>
  To  : rasmb@alpha.bbri.org
  Date: Wed, 18 Oct 00 14:38:31 EDT

ultra short cells

Hi all!  Although I do not doubt that Allen and Marc "invented" the thin
cell, I must point out that I we published a paper on "Equilibrium
Sedimentation Studies of the Aggregation of Methylene Blue" J. Phys. Chem.
76: 4062 (1972) in which we used cells of as small as
about 0.04 mm (red gasket material compressed). But I must confess that
some time before that I had a conversation with Robley Williams (Dave Yphantis'
first grad student I believe, who was a post-doc at Yale at the time)
about using ticket punches to punch out oval or "T" shaped channels
in thin plastic for such a purpose.  I assume therefore that
he had done this previously.
    Laila, Jim Cole is dead on, if you are going to study steep gradients
you must make sure that you either refocus into the 2/3 plane or use the
window spacers (like those designed by Les Holliday) to put the center piece
into the correct position.  Since you have generated some steep gradients
in the past, I suggest that you be careful.  But we think we talked
about this with you when you were here.  Finally, have you decided how to
deal with the the non-ideality you will probably incur under those conditions?

conversation.

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
EMORY.BRASWELL@UCONN.EDU