Dear Ingrid,
This is a slightly modified copy of my posting on the same topic in 2001:
"Many years ago at Imperial College we did a fairly systematic experiment on
vibration using lysozyme (hanging drops in Linbro trays).
We placed one tray in the basement on a very solid concrete base, one tray was placed
in an incubator, frequently used and known to vibrate a little
(with frequent door opening and closing), and the third tray was placed on a
rather strongly vibrating metal plate hanging from
a ceiling on a piece of wire. The vibrations were produced by a small motor
with an acentric piece of metal attached to its rotor.
The trays were examined at regular intervals. Crystals grew in all of them.
The basement tray gave fewer but bigger crystals, but this may have been a
small temperature effect - temperature was not controlled very well.
Crystals from all trays were nice, they diffracted to the same resolution,
with virtually identical Wilson distribution. After this experiment we
stopped worrying about vibration."
Tadeusz
PS. I think now that some crystallisation experiments may be more sensitive to vibration and resulting mixing of the drop content. No firm evidence, though...
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Sent by: [EMAIL PROTECTED] 01-Aug-2006 15:02 |
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Dear crystallographers,
While this is not a directly CCP4-related project, no crystal (or bad quality ones) means not much use of CCP4 ... hence the following inquiry. I am involved in the design of a new crystallisation lab with temperature-controlled rooms, which we have found to be typically quite prone to internal vibrations. A little vibration is probably not an issue in most of the cases, but how to define what is acceptable and what is not?
Most of the time people define good crystallisation environment as vibration-free, but I suspect that 0 vibration is not a value that can be typically achieved in labs (can it be achieved at all?), and while there are means of measuring vibration levels, I could not find any numeric references...
...which leads me a long list of naive questions:
- does anyone have performed any vibration level measurement in their labs
and defined a threshold for acceptable conditions?
- are scientists performing their crystallisation experiments in temperature-controlled rooms satisfied with the vibration levels?
- do some of you recommend some devices/brands to reduce vibrations applied to the crystallisation trays? (I heard about vibration-free shelves or insulation pads, is this any good?)
- any advice about how to handle vibration issues welcome!
Thank you very much to all of you in advance,
Ingrid Mechin
