[RASMB] XLA run at 37 degrees

[Tom Laue]

Hi all-
As you have heard, there is great variability in success with operating 
the XL/I at 37 C. Here are a couple of generalizations from over the years-
- Oil vapor is the big problem, with the major source being the 
diffusion pump
- The absorbance system is far less sensitive to condensed oil vapor 
than the interference system.
- For the interference optics, the condensing lens (no pun intended) 
tends to fog up, even if there is no overt oil deposition in the rest of 
the chamber
- Oil condenses preferentially at the cold spots in the chamber, so 
pre-warming your rotor/cells reduces oil condensation on the samples
- If you have even the slightest vacuum leak in your vacuum system, oil 
deposition will be a problem
Walter and David's work with the turbomolecular pump is very encouraging!
Best wishes,
Tom

Trushar Patel wrote:
> Dear all,
>
> I have done experiments at 30C using XL-I and it worked superbly.
>
> Regards,
>
> Trushar
>
> **********************************************
> Trushar Patel
> PhD Student
> National Centre for Macromolecular Hydrodynamics
> School of Biosciences
> University of Nottingham
> Sutton Bonington
> LE12 5RD, UK
> Tel: +44 115 9516149(Lab)
>
> E-mail : stxtrp at nottingham.ac.uk
> www: http://www.nottingham.ac.uk/ncmh/students/trushar.html
> ***********************************************
>   
>>>> "Christine Ebel" <christine.ebel at ibs.fr> 05/12/06 6:37 PM >>>
>>>>         
> Hello,
>
> I have a bad experience with my unique run at 37°C.
>
> I had oil condensation.
>
> In consequence, for this run, and all the experiments after, (until the
> Beckman man came and washed everything) even if I washed the filter, where
> consensation was obvious, interference was unusable: it become noisy (very
> noisy) after about two hours of run.
>
> The problem is not so obvious with absorbance.
>
> I am curious to know at what temperature we can run using interference
> optics.
>
> Christine
>
>  
>
> Christine EBEL
>
> Institut de Biologie Structurale UMR 5075 CEA-CNRS-UJF
>
> 41 rue Jules Horowitz, 38027 Grenoble Cedex 1, France
>
> Tel (33) (0) 4 38 78 96 38; Fax (33) (0) 4 38 78 54 94 
>
> christine.ebel at ibs.fr
>
>  <http://www.ibs.fr/content/ibs_eng/presentation/lab/lbm/ebel.htm>
> http://www.ibs.fr/content/ibs_eng/presentation/lab/lbm/ebel.htm
>
> -----Message d'origine-----
> De : rasmb-bounces at server1.bbri.org [mailto:rasmb-bounces at server1.bbri.org]
> De la part de Dean Malencik
> Envoyé : vendredi 12 mai 2006 18:28
> À : RASMB at server1.bbri.org
> Objet : [RASMB] XLA run at 37 degrees
>
>  
>
> Hello,
>
>  
>
> I have been asked to do a run at 37 degrees on the XLA analytical
> centrifuge.  Does anyone have any pitfalls to anticipate or is it even
> feasible to do a run at this temperature?  Any differences if the run is a
> velocity or equilibrium run? 
>
>  
>
> Thanks.
>
>  
>
> Dean Malencik
>
>
>
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