From: Philo, John <jphilo@amgen.com>
  To  : 'rasmb@bbri.harvard.edu' <rasmb@bbri.harvard.edu>
  Date: Fri, 24 Jan 1997 07:53:02 -0800

RE: Missed scans under Windows 95

One further detail regarding Tom's excellent point.  On some computers
(including the IBM models supplied by Beckman), it is not sufficient to
just turn off the power saving features via the Control Panel.  You also
need to disable power management in the hardware settings stored in the
computer CMOS configuration information.  This is usually accessed by
entering a SETUP utility during system boot-up (often by hitting ESC or
F1 before Win95 starts).

Since doing this I have not had any COM hang-ups (using Win95 and
version 3.01h) while the system is actually scanning or waiting for
scans.  However, just a few days ago I did get a communications problem
just when I initiated a manual scan, and had to turn off the centrifuge
to get things going again.  I have been told that there are still some
software bugs that can lead to occasional COM port lock-up while you are
setting up a scan.

I think all users would agree that what is really needed is a serial
communications reset button or key combination on the XL-A/I itself, so
we could restart serial communications WITHOUT shutting down the
centrifuge and potentially having to start over on a long equilibrium
run.

John Philo

>----------
>From: 	Tom Laue[SMTP:Tom.Laue@unh.edu]
>Sent: 	January 24, 1997 5:38 AM
>To: 	rasmb@bbri.harvard.edu
>Subject: 	Missed scans under Windows 95
>
>Dear RASMBers,
>A remark arose recently that the XLA 3.01g software would not run correctly
>under Windows 95. In particular, it was noted that the program would stop
>scanning afterwhile, hanging up with a COM port failure. 
>
>The problem is not in Windows 95 or the program per se, but with the "Power
>Saving" features of some computers. Windows 95, but not Win 3.1x, is
>designed to take advantage of these features. Unfortunately, one that
>effectively shuts down all CPU activity (except checking for activity on
>the keyboard or the mouse) effectively shuts out the XLA communications.
>Disabling this feature (by turning off the "Power Saving" choice under the
>"Control Panel") will fix the problem. We have found Win95 more stable than
>Win 3.xx when running the centrifuges.
>
>Hope this helps!
>Tom Laue
>
From ajr@leicester.ac.uk  Fri Jan 31 09:03:28 1997
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From: "Dr A.J. Rowe" <ajr@leicester.ac.uk>
Message-Id: <14259.199701311424@hawk.le.ac.uk>
Subject: vbar in urea
To: rasmb@bbri.harvard.edu
Date: Fri, 31 Jan 1997 14:24:56 +0000 (GMT)
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Status: RO

Hello rasmbers !

Does anyone have an idea on the following problem ?

We are working with a trimeric protein which (for reasons no doubt good to its
fond parents) wishes to be studied in 9M urea/100 mM Pi. The sedimentation
velocity diagram looks beautiful, one component (SVEDBERG), s value maybe 30%
slower that native trimer in normal buffer, so has to be a 'swollen trimer'
i.e. subunit interaction remains strong, but each monomer is swollen. 

Equilibrium analysis shows pretty much the same story, but the values are a
modest way off expected, if we stick with the normal vbar. We do not fancy our
chances of getting a decent empirical vbar with the DDM (a really good c value
in so horrible a solvent sounds tricky) - is there any at least half-decent
guess one can make as regards even the sign of the change in vbar ?

The fact that one cannot even assume a change to a random coil type structure
does not help - obviously the polypeptide chain must be seriously constrained.

Anyone out there met a system like this before ?

Arthur Rowe

***************************************************
Dr Arthur J Rowe
Director
UK National Centre for Macromolecular Hydrodynamics
Leicester Laboratory
Adrian Building
University of Leicester
Leicester LE1 7RH    UK

Tel: +44 (0)116 252 3448
Fax: +44 (0)116 252 5602
ajr@leicester.ac.uk
***************************************************