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This is not really a CCP4 question, but I think it is the best forum
to get a straight answer from synchrotron beamline scientists.
It seems to be generally accepted by synchrotron users that once the
crystals on the application have been shot, the time is then to be
used for "other crystals". All of the people I ask routinely bring
"other crystals", even crystals from other investigators in order to
use up the extra time that opens up when data collection is efficient
or "approved" crystals do not pan out.
I understand the need for an accurate manifest to be supplied to the
beamline coordinators before work begins. "Unauthorized" crystals may
pose unacceptable hazards and disposal problems. I am certainly not
comfortable with the idea of the previous users leaving unknown hazards
and wastes to contaminate the lab.
The delay between application and beam time is generally quite long, or
at least sufficiently long that project aims and priorities may change.
A molecular replacement problem may be abandoned in favor of derivatives,
or ligand co-crystals may have been obtained. A better diffracting mutant
may have been crystallized. Some lattitude seems to be allowed, based on
the application materials.
One important area where the rules seem strict deals with proprietary
research. Beam-time for proprietary reseach is not free. Many investigators
may be tempted to do a bit of proprietary research on their "free" time.
I have not heard of anyone doing this, but it seems it could become a
problem as more academic researchers work on proprietary projects.
I am certain that the rules vary among the consortia that operate the beam
lines. Since they have made significant financial contributions toward
beamline construction, maintainance and support, it should fall on us
users to follow their guidelines.
So, from the beamline scientists and sector coordinators:
What is the working (as opposed to stated) policy with respect to these
"other crystals"? How much different must the crystal be to be considered
"unauthorized"? When is the latest that a revised manifest can be sent by the
Lisa Edberg (205)934-1611 firstname.lastname@example.org
Center for Macromol. Cryst., Univ. Alabama-Birmingham
Life is a hanging drop.