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 <[log in to unmask]> 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
>> [log in to unmask]
>>
>> ________________________________
>>
>> From: CCP4 bulletin board [mailto:[log in to unmask]] On Behalf Of Frank
>> von Delft
>> Sent: Friday, November 18, 2011 2:27 AM
>> To: [log in to unmask]
>> 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 <[log in to unmask]>
>>
>> Date:
>>
>> November 17, 2011 4:00:06 PM CST
>>
>> To:
>>
>> [log in to unmask]
>>
>> Subject: [ccp4bb] crystal orientation during data collection
>>
>> Reply-To:
>>
>> yanwu huo <[log in to unmask]>
>>
>> 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:[log in to unmask]
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>
>
>
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