[3dem] Gatan 914 Holder Woes

[Cindi Schwartz]

Hello List,

We are having problems with plunge-frozen cryo grids only when using  
our 914 holder. Basically, we are getting what I like to call, the  
cauliflower effect. Sometimes it's very subtle and sometimes it's  
blatant. Here are the facts:

1. This is happening to multiple people with multiple sample types
2. This happens when using the vitrobot or by hand-blotting
3. Grids from the same freezing session viewed with a Gatan 626 holder  
do not have bad ice
4. Temperature measurements of the 914 holder during all phases of  
loading the holder and inserting it into the microscope never get  
above -170C
5. Grids have this regardless of which of 2 tanks of ethane we use

Any ideas of what may be causing this would be greatly appreciated.

The pictures were too big to send to the list (although quite small by  
my standards). They are posted on our ftp site:

ftp://bio3d.colorado.edu/914

Thanks,
Cindi



**********************************
Cindi L. Schwartz
University of Colorado, Boulder
Dept. MCDB
BL3DEMC
O: 303-492-7980
F: 303-735-0770
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