[RASMB] equilibrium run questions

[John Philo]

Henry,

> 2) I am getting very choppy absorbance readings at high radius (above 6.5 
> cm) in all three cells.  Could this be due to a dirty lamp, dirty 
> detector, both, or something else?

Yes, yes, yes, and yes! 

One 'something else' is that the lamp assembly could be poorly aligned and
consequently there is low light intensity at higher radii. Do a scan of an
empty hole in the rotor and request the intensity data---you will see a
profile of the intensity vs. radius. If you see a big variation (where +/-
20 to 30% is normal) that could be due to the alignment problem, but also
could be a dirty photomultiplier tube. 

John Philo



-----Original Message-----
From: rasmb-admin at rasmb-email.bbri.org
[mailto:rasmb-admin at rasmb-email.bbri.org] On Behalf Of Henry N. Higgs
Sent: Thursday, October 02, 2003 1:03 PM
To: rasmb at rasmb-email.bbri.org
Subject: [RASMB] equilibrium run questions


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Hello,
I have had two problems setting up equilibrium runs:
1) Upon advisement, I bought the side-load 6 chamber epon equilibrium
centerpieces.  THEY STINK!  I can never fill the outer-most chambers without
having liquid leak out the holes.  Does anybody have any advice on how to
load these?
2) I am getting very choppy absorbance readings at high radius (above 6.5
cm) in all three cells.  Could this be due to a dirty lamp, dirty detector,
both, or something else? Thanks, Harry Higgs

_________________________________
Henry N. Higgs, PhD
Assistant Professor of Biochemistry
413 Vail Building, HB 7200
Dartmouth Medical School
Hanover NH 03755-3844

phone 603-650-1420
FAX     603-650-1128
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