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  From: dr. jack correia <>
  To  :
  Date: Tue, 10 May 94 10:10:55 -0500

Re: Different Points of View

>Received:  by (5.57/6.1s-FWP);
>	   id AA13937; Tue, 10 May 94 10:03:55 -0500
>Date: Tue, 10 May 94 10:03:55 -0500
>From: dr. jack correia <>
>Message-Id: <>
>To: rasmb
>Subject: Re: Different Points of View
>   If your were offended by my letter, my apologize, but I made it clear I was
>blaming the sloping baseline.  Goldman didn't roll over in his grave when I
>also mentioned  2nd moment will not work under these conditions!  Bo did
>not create the method!  His software is a nice package!  We are very happy
>to have it, but it doesn't begin to tap the full range of methods of analysis
>to be applied to the XL-A.  When it is working correctly, I accept that the
>VanHolde-Weischet method is very instructive.  With my machine every
>sample is strongly nonideal - tubulin, tau, kinesin, nucleolin, peptides,
>DS-214mer.  (And yet by S20,w vs. concentration none of them are!)
> We do it after every vel run, but I do not trust our results, and
>I tell everyone to also do S20,w analysis and a cautious 2nd moment.

[ It does surprize me that we get reasonable MW by equilibrium methods!
We have done tubulin, a 9000 MW peptide and a 90000 kinesin head dimer!]
>   I will recontact Beckman and try to get my service person (Dennis Foyt)
>to correct this, but I am still not clear what to fix!
>Related topic:  This newsletter is doing alot of Beckman bashing!  The
>bottom line is witjout the XL-A I would not be doing centrifugation now, and
>I have many potential projects and collaborations.  I appreciate the
>frustration of noninformation, corporate response, defensiveness coming
>from individuals at Beckman!  But some of us also have corporate, legal,
>financial obligations that supersede or color our opinions or willingness to
>share information.  My experience is that the Beckman people eventually
>get me the answer or information, although I may have to hit the correct
>topic or question to get the info.  Remember, the model-E was improved by
>users not Beckman.  Methods of analysis, centerpieces, lasers, cameras, etc.
>- all by users!  Finally the interference system is up and running.  Both Tom
>and Walter have functioning systems and ?next? year for a modest fee, we
>all will too!

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