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From: Arthur Rowe <arthur.rowe@nottingham.ac.uk>
To : E.braswell <BRASS@UCONNVM.UConn.Edu>
Date: Fri, 20 Oct 2000 15:39:46 +0000
Re: "squashed" gaskets as centerpieces
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Hi Emory (and all) !
I have never actually seen experimental data showing the effects of Wiener
skewing on absorption traces, and its an interesting point as to what will
happen. The distortion of the wave front must occur regardless of what
imaging system you are using - in other words, the rays which are forming
your log(I0/I) signal will not, as I understand it, refer to exactly the
same radial position in the solution as in the reference channnel. However,
given the fact that absorption optics are of considerably lower precision
than refractometric optics, in the real world it may not matter too much.
As you say, its the absolute value of dn/dr that matters. Alas.
All best
Arthur
*****************************************************
Arthur J Rowe
Professor of Biomolecular Technology
University of Nottingham
School of Biological Sciences
Sutton Bonington
Leicestershire LE12 5RD UK
Phone/voicemail +44 (0)115 951 6156
Phone/fax +44 (0)115 951 6156/7
email arthur.rowe@nottingham.ac.uk
arthur.rowe@connectfree.co.uk
Web http://www.nottingham.ac.uk/ncmh/business
*****************************************************
----------
>From: "E.braswell" <BRASS@UCONNVM.UConn.Edu>
>To: rasmb@bbri.harvard.edu
>Subject: "squashed" gaskets as centerpieces
>Date: Fri, Oct 20, 2000, 1:58 pm
>
>Howdy folks! Arthur, first of all we used the squashed gaskets and other
>thin plastic only for absorbance work, which I think can get you some
>reasonable data. For interference data I fully agree. But when you say
>for interference, "high gradient" do you mean absolutely or relatively?
>Obviously you are implying the former. It would seem natural that one
would
>run in a thinner cell to reduce the apparent gradient--but I think you are
>saying that doing this does not help. That so? 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
>EMORY.BRASWELL@UCONN.EDU
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<TITLE>Re: "squashed" gaskets as centerpieces</TITLE>
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<BODY BGCOLOR=3D"#FFFFFF">
<FONT SIZE=3D"2">Hi Emory (and all) !<BR>
<BR>
I have never actually seen experimental data showing the effects of Wiener =
skewing on absorption traces, and its an interesting point as to what will h=
appen. The distortion of the wave front must occur regardless of what imagin=
g system you are using - in other words, the rays which are forming your log=
(I0/I) signal will </FONT><U>not</U><FONT SIZE=3D"2">, as I understand it</FON=
T><U>,</U><FONT SIZE=3D"2"> refer to exactly the same radial position in the s=
olution as in the reference channnel. However, given the fact that absorpti=
on optics are of considerably lower precision than refractometric optics, in=
the real world it may not matter too much.<BR>
<BR>
As you say, its the absolute value of dn/dr that matters. Alas.<BR>
<BR>
All best<BR>
<BR>
Arthur<BR>
*****************************************************<BR>
Arthur J Rowe<BR>
Professor of Biomolecular Technology<BR>
University of Nottingham<BR>
School of Biological Sciences<BR>
Sutton Bonington<BR>
Leicestershire LE12 5RD UK<BR>
<BR>
Phone/voicemail +44 (0)115 951 6156<BR>
Phone/fax +44 (0)115 951 6156/7<BR>
email arthur.rowe@nottingham.ac.uk<BR>
arthur.rowe@connectfree.co.uk<BR>
Web http://www.nottingham.ac.uk/ncmh/business<BR>
*****************************************************<BR>
<BR>
----------<BR>
>From: "E.braswell" <BRASS@UCONNVM.UConn.Edu><BR>
>To: rasmb@bbri.harvard.edu<BR>
>Subject: "squashed" gaskets as centerpieces<BR>
>Date: Fri, Oct 20, 2000, 1:58 pm<BR>
><BR>
<BR>
>Howdy folks! Arthur, first of all we used the squashed gaskets and oth=
er<BR>
>thin plastic only for absorbance work, which I think can get you some<B=
R>
>reasonable data. For interference data I fully agree. But when you sa=
y<BR>
>for interference, "high gradient" do you mean absolutely or r=
elatively?<BR>
>Obviously you are implying the former. It would seem natural that one =
would<BR>
>run in a thinner cell to reduce the apparent gradient--but I think you =
are<BR>
>saying that doing this does not help. That so? Emory<BR>
><BR>
>Emory H. Braswell<BR>
>Professor of Biophysics and Head,<BR>
>National Analytical Ultracentrifugation Facility<BR>
>U-149<BR>
>University of Connecticut<BR>
>STORRS, CT 06269-3149<BR>
>TEL 860 486 5032<BR>
>FAX 5005<BR>
>EMORY.BRASWELL@UCONN.EDU<BR>
<BR>
<BR>
</FONT>
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