[3dem] weird ice?

[Zongli Li]

Hi Peter,

Whether it is because the clip ring didn't make good contact with grid or
something else, the cryo-grid got warmed up inside the column and freeze
dried due to the high vacuum.
We do see this kind of ice on both F20 and Polara from time to time, and
believe it happened due the loose contact between grid and holder/clamp
ring.

Best,

Zongli

On Wed, Oct 17, 2018 at 10:32 AM <duncan.sousa at rcn.com> wrote:

> 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
>
> ------------------------------
> *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
> <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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