I would interpret "random" as aimed to be uniformly distributed, or
highly diverse,... continuing this chain of definitions and having a
precise kappa goniometer in hand, we can easily arrive to a "planned"
strategy to follow. Certainly, if you can get only a few frames per xtal
- Frank (vD), do you remember when we had a project like this together-
you may not have the luxury of being able to afford to loose a complete
frame(s) just to get to know the initial orientation of the crystal(s).
In any case, I am happy to learn that our solution 'STAC' is useful for
the community. Actually, we are organising an International Kappa
Workgroup Meeting in Berlin on Nov 28-29. Registration is normally over,
but if there is anyone interested in learning more about current
developments for sample reorintation on synchrotron beamlines, please
contact us directly and join us in Berlin.
http://www.helmholtz-berlin.de/forschung/funkma/soft-matter/forschung/bessy-mx/kappa-meeting/index_en.html
Sandor
Jacob Keller wrote:
Generally speaking, don't we agree that "planned" or "rational" is
better than "random?" (Having trouble understanding the argument for
randomness here...)
Jacob
On Fri, Nov 18, 2011 at 9:40 AM, Sanishvili, Ruslan <rsanishv...@anl.gov> wrote:
Depending on the crystal shape, “random orientation” is not always random.
Many crystals have tendencies of sitting themselves in one predominant
posture in the mount. Compounding this, many experimenters have tendencies
of rotating the mount into a specific orientation when centering. Then
crystal orientation ends up being not random at all, so understanding it’s
true orientation as my neighbor Frank suggests can be highly beneficial.
Cheers,
N.
Ruslan Sanishvili (Nukri), Ph.D.
GM/CA-CAT
Biosciences Division, ANL
9700 S. Cass Ave.
Argonne, IL 60439
Tel: (630)252-0665
Fax: (630)252-0667
rsanishv...@anl.gov
________________________________
From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Frank
von Delft
Sent: Friday, November 18, 2011 2:27 AM
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] crystal orientation during data collection
I believe you achieve completeness more quickly (fewer crystals) if you just
take random orientations. At least, that's what I learnt from Dave Stuart.
phx
On 18/11/2011 04:20, Frank Murphy wrote:
Yanwu,
I surmise from your question that you are inquiring how to go about
collecting from many crystals optimally. Merging data ex post facto is a
totally different kettle of fish.
In my opinion, the most robust way to go about this is to use a kappa
goniometer as Jim suggested (I am most familiar with the MK3). Since you
intend to collect from many crystals, align the first and all subsequent
crystals to the same easily attainable (or seemingly so) orientation, and
then collect the sweep suggested by your data collection strategy program of
choice.
To achieve this at NE-CAT, we have a GUI-based system that used STAC for
orientation determination and BEST for strategy generation. As Jim
suggested, more options than STAC exist.
If anyone is unable to get to a kappa goniometer, they can employ Mosflm or
XDS (Xplan) to generate strategies for data collection from a crystal taking
into account previously collected data. This is not nearly as robust a
solution, but is a workable substitute (and also automated at NE-CAT).
I know there are other ways to achieve similar results, but I have suggested
the methods I am most familiar with...
Yours,
Frank Murphy
Begin forwarded message:
From:
yanwu huo <applehu...@gmail.com>
Date:
November 17, 2011 4:00:06 PM CST
To:
CCP4BB@JISCMAIL.AC.UK
Subject: [ccp4bb] crystal orientation during data collection
Reply-To:
yanwu huo <applehu...@gmail.com>
Hi,
I worked on a crystal sensitive to radiation damage, So I need to merge many
crystal to obtain complete dataset, Does anyone know such program that can
tell crystal orientation after first frame exposure.
Thank you in advance.
--
Thank you very much and all the best,
Yanwu Huo
Postdoctoral Associate
Department of Molecular Biology and Genetics
Cornell University
Ithaca, NY, 14853
Email:yh...@cornell.edu
