[3dem] weird ice?

[duncan.sousa at rcn.com]

Hi, 


I agree. It looks like freeze dried protein solution. I'd definitely check the holder first, but if you can't find the problem there then check every stage that involves a grid transfer. For example, I've seen this happen when the LN2 level gets too low in a dewar and the grid sits in cold N2 gas for a while. 



Duncan 

----- Original Message -----

From: "Mariena Silvestry Ramos" <ms3289 at cornell.edu> 
To: "Eric Hanssen" <ehanssen at unimelb.edu.au> 
Cc: 3dem at ncmir.ucsd.edu 
Sent: Tuesday, October 16, 2018 8:39:43 PM 
Subject: Re: [3dem] weird ice? 

Hi Peter, 


I second Eric. Looks like a bad contact (or lack of) between the clipring and the grid. This will cause the ice to devitrify and "crust" and it you park the beam, the stuff will fold back and do all sorts of weird moving/behaviour. I'd check if your clipping mechanism is good. It could be that the wire that keeps the grid put in is worn, or, depending on the model, the ring is crossthreaded. Changing the clip wire is generally easy to do, with the right tools. I've done it a couple of times and it fixes the issue. Definitely contact Gatan with any questions. Mark Dods and/or Braden Bowers are at the factory in Warrendale and can give you advice on what to test and the part(s) to purchase. 


Best of luck! 


Mariena 


Sent from my Game Boy 

On Oct 16, 2018, at 8:15 PM, Eric Hanssen < ehanssen at unimelb.edu.au > wrote: 






HI Peter, 
They both look like the clip ring in your 626 (I am guessing that is the holder you are using) is not clipped properly, hence your vitreous ice has devitrified and in the second picture it is even worse it has sublimed in the microscope and you have only the protein/salt scaffold left. 
Regard 
Eric 




----------------- 
Assoc. Prof Eric Hanssen 

Head - Advanced Microscopy Facility 
Honorary Principal Fellow – Department of Biochemistry and Molecular Biology 

President Australian Microscopy and Microanalysis Society 

Bio21 Molecular Science and Biotechnology Institute 
30 Flemington Road - The University of Melbourne - Victoria 3010 - Australia 
email: ehanssen at unimelb.edu.au | Office: +61 3 83442449 | Microscope: +61 3 83442509 
Web: www.microscopy.unimelb.edu.au 

<image001.png> <image002.png> 





From: 3dem [ mailto:3dem-bounces at ncmir.ucsd.edu ] On Behalf Of Peter Shen 
Sent: Wednesday, 17 October 2018 10:39 AM 
To: 3dem at ncmir.ucsd.edu 
Subject: [3dem] weird ice? 


Hi everyone, 



We've recently started to see some funky ice on our TF20. Here are a couple of screenshots: 



https://www.dropbox.com/sh/mlfado5rf9o447c/AAAt9VJM28KG6sCaNnCXIXQga?dl=0 



Has anyone seen this before? We see this regardless of sample and grid type (a few different protein preps and UltrAuFoil/Quantifoil tested). Any insight would be greatly appreciated! We're pulling our hair out here... 



Peter 


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