according to literature,see below and references
http://www.px.nsls.bnl.gov/courses/papers/ZD_EG_papers.html,
it is not clear that liq. propane plunged item would cool
faster. (whilst i havent tested this)...
Would anyone have actual experimental data with protein crystals
on the hyperquenching suggested by
Warkentin, V. Berejnov, and R. E. Thorne, J. Appl. Cryst. (2006) 39,
805-811. (no diffraction data in the paper). in particular with
small samples.
thanks,
Tommi
Quoting Petr Leiman <[log in to unmask]>:
> >> yes you are right, but I assumed if people see a cloud of condensed
> >> fog over their LN2 bath they should remove that by
> >> a) filling up the bowl completely e.g. some LN2 drips out of the bowl
> >> b) blow the fog away before you dip
>
> I think the original poster meant the relatively low heat conduction of
> liquid N2, which causes boiling around the crystal immediately after
> plunging.
>
> The best way to freeze things is to put a small container of liquid
> ethane
> or propane into a liquid N2 bowl, and plunge into the ethane/propane
> (this
> methods was suggested earlier).
>
> Petr
>
>
--
Tommi Kajander, Ph.D.
Macromolecular X-ray Crystallography
Research Program in Structural Biology and Biophysics
Institute of Biotechnology
P.O. Box 65 (Street address: Viikinkaari 1, 4th floor)
University of Helsinki
FIN-00014 Helsinki, Finland
Tel. +358-9-191 58903
Fax +358-9-191 59940
|