[RASMB] Temperature control

[John Correia]

It is clearly unreasonable to avoid waiting for temperature before a run
regardless of the small effect a single deg shift might have on density
or viscosity.  Can you mentor character flaws?  Alternatively waiting
for hours defeats the purpose with unstable systems.   But steep
reversible temp dependence upon association clearly might magnify this,
and in fact I would like to hear if any systems demonstrate this.  The
one I know about is the TMV self-association of capsid studies done by
Todd Schuster & collaborators years ago....extreme temp dependence  
coupled with slow kinetics.  I recall elaborate temperature control
boxes for the rotors and double walled incubation chambers - Styrofoam
in Styrofoam - keeping Steve  Shire & John Steckert entertained for
years.   

What is not being mentioned is that the whole deg units allowed on the
XLA/I while probably precise to a few 0.1's are not necessarily
accurate.  I am only aware of the NAUF in Storrs also calibrating their
instrument with the procedure developed by Stafford.  (Liu & Stafford
1995 Anal Biochem - 224, 199-202.) I've done it twice 5 years apart and
saw only a minor change - at most temperatures from 4 to 40 deg the
values on my machine are low by 0.1 to 0.4 deg.  Thus we report
experimental results at 24.7 not 25, and we measure density at those
temperatures as well.   But Emory once told me they had an instrument
that was 5 deg low at a setting of 37.  Any other observations out
there?

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 Dr. John J. "Jack" Correia
 Department of Biochemistry
 University of Mississippi Medical Center
 2500 North State Street
 Jackson, MS  39216
 (601) 984-1522                                 
 fax (601) 984-1501                             
 email address: jcorreia at biochem.umsmed.edu     
 homepage location: http://biochemistry.umc.edu/correia.html  
 dept homepage location:    http://biochemistry.umc.edu
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