Contents of this Issue:
1. Science Highlight —
The Chemical Form of Mercury in the Fish We Eat
(contact: Y. Arai, yarai@clemson.edu)
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The results, based on mercury x-ray absorption spectroscopy data, demonstrated that mercury was accumulated almost exclusively as methylmercury-cysteine complexes in the muscle tissues of piscivorous freshwater fish from both GUA and LAH. This result, consistent with observations for several marketed marine fish species, suggested that speciation of bioaccumulated mercury at high trophic levels was consistent over a wide range of ionic strengths and mercury sources. In terms of management implications, the dominance of methylmercury cysteine complexes in muscle tissues of fish obtained from such contrasting environments and exposure conditions suggest that one may be able to greatly simplify toxicological models for fish consumption over wide-ranging aquatic habitats by assuming that piscivorous fishes, a food source for wildlife and humans, consistently accumulate mercury as cysteine complexes in their tissues.
To learn more about this research, recently published in the journal
Environmental Science & Technology, see the full scientific highlight at:
http://www-ssrl.slac.stanford.edu/research/highlights_archive/ch3hg_trophictrans.html
2. Science Highlight —
How Stents Take the Strain
(contact: A. Mehta, mehta@slac.stanford.edu)
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| Maps of the deviatoric strain of the B2 austenite along the vertical y axis (eyy) from x-ray diffraction analysis. |
3.
2007 Spicer Young Investigator Award to be Presented to Hugh Harris
—By Ken Kingery
Congratulations to Hugh Harris who has been chosen to receive this year's William E. Spicer Young Investigator Award. Now in its fourth year, the award honors one of the founders of SSRL by recognizing a young scientist who has made important technical or scientific contributions that benefit the light source community. The award will be presented to Harris at the joint SSRL/LCLS Users' Meeting on October 1-2.
Harris is a lecturer at the School of Chemistry and Physics, University of Adelaide, Australia. His research over the last several years has taken him to light source facilities around the world and involved many different subjects in bioinorganic chemistry. His postdoctoral time at SSRL included research in x-ray microprobe mapping of species in tissues and structural determinations using x-ray absorption spectroscopy and associated DFT calculations. Harris' research at the University of Sydney involved studies of individual mammalian cells exposed to drugs, carcinogens, toxins and physiological stimuli, as well as structural determinations of the local structures about metals in proteins, model complexes, cells and tissues. Results and techniques learned from this work hold many exciting possibilities to future medical treatments of major diseases. "Hugh is a thoughtful, creative and hard-working individual with excellent experimental skills," said Peter Lay, an Australian Professorial Fellow and Personal Chair in Inorganic Chemistry at the University of Sydney. "His research about to be published will have a broad impact on biology and medicine."
Harris has had visible impact in the application of x-ray techniques to bioinorganic chemistry and the life sciences as evidenced by his numerous publications, including first author publication in the journal Science. This award recognizes his breadth of instrumentation skills, knowledge and a willingness to apply these to significant problems as well as his practical applications of x-ray microscopy to his research area. "Pioneering, outstanding users such as he are critical for the success of synchrotrons, as their results demonstrate to a broader community the benefits and possibilities of synchrotron-based science, in a language and form that is directly understood and applicable to diverse scientific questions in these communities," said Stefen Vogt, X-ray Science Division, Argonne National Laboratory.
Harris has been invited to give a presentation on his work during the Young Investigators Session of the SSRL/LCLS Users' Meeting. http://www-conf.slac.stanford.edu/ssrl-lcls/2007/
4.
Jessica Vey to Receive 2007 Klein Award
Congratulations to Jessica Lynn Vey, a graduate student in Chemistry at the Massachusetts Institute of Technology (MIT) and recipient of the 2007 Melvin P. Klein Scientific Development Award. The Klein award will be presented to Vey at the joint SSRL/LCLS Users' Meeting on October 1-2.
The Klein Award honors a graduate or undergraduate student for outstanding research using SSRL facilities. The award includes a $1,000 stipend for the recipient to present their work at a scientific conference.
During the past year, Vey's research has centered around two projects. To begin her graduate studies, Vey solved the crystal structure of the essential cysteine desulfurase, an enzyme that provides sulfur for iron sulfur cluster biosynthesis under anaerobic conditions, from the bacteria Synechocystis. As an encore performance, Vey then successfully crystallized pyruvate formate lyase activating enzyme (PFL-AE), an enzyme that enables anaerobic glucose metabolism. This very challenging project had been abandoned by another group after six years before being crystallized —and later solved— by Vey.
Vey plans to use the $1,000 to present her work at the 2008 Graduate Research
Seminar: Bioinorganic Chemistry in Ventura, California early next year. She
will also give a presentation on "Structural Basis for Glycyl Radical Formation
by Pyruvate Formate-lyase Activating Enzyme" during the Young Investigators
Session of the SSRL/LCLS Users' Meeting.
http://www-conf.slac.stanford.edu/ssrl-lcls/2007/
"Jess accomplished more in her first year of graduate school than most students do in two to three years," said Catherine Drennan, Associate Professor of Chemistry at the Massachusetts Institute of Technology. "Students like Jess come along only once or twice in a career, and I am enjoying every minute of her time in my group."
5.
Register for 2007 SSRL/LCLS Users' Meeting and Workshops, September
28-October 3
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6.
Learn About SR Techniques or Brush Up Your Skills at September 30 Workshop
On Sunday, September 30, ALS and SSRL will hold a joint workshop on Synchrotron
Radiation Techniques. This workshop will be held at SLAC and will provide a
basic introduction to the various experimental techniques available at
synchrotron facilities with a tutorial-style approach. The content will be
geared towards scientists who are new to synchrotron radiation and its
applications, and will be appropriate for graduate students, synchrotron staff
members, and principal investigators who are considering incorporating
synchrotron experiments into their research. The workshop panelists will
address: 1) unique advantages of synchrotron-based experiments, 2) how the
experiments work, 3) questions that one tries to answer when using a particular
technique, 4) what kinds of equipment and sample preparation are necessary to
carry out a particular experiment, and 5) comparisons to other non-synchrotron
techniques (if any) that are used to answer the same kinds of questions.
Agenda: http://www-conf.slac.stanford.edu/ssrl-lcls/2007/program.htm#SSRL-ALS
7.
Several Concurrent Workshops Offered on October 3
Scientific Opportunities for Studying Laser Excited Dynamics at the LCLS,
October 3
(contact:
K. Gaffney, kgaffney@slac.stanford.edu)
The Photon Science Directorate at the SLAC will host a workshop to discuss the
scientific future of the predominantly laser pump, x-ray probe (XPP) end
station at the Linac Coherent Light Source (LCLS). We heartily invite all
scientists desiring to conduct science at the XPP facility. The workshop will
take place from 8am-5pm on Wednesday, October 3. The workshop will update the
community on the LCLS capabilities and timeline, present the design and
experimental capabilities for the XPP end station, and discuss procedures for
acquiring experimental access during LCLS and XPP commissioning, as well as the
procedure for transitioning from commissioning to general user access. The
workshop will have invited talks discussing the scientific opportunities
generated by the LCLS and the XPP facilities and provide the opportunity for
brief contributed presentations. The topics to be covered will include
LCLS-based studies of phase transition dynamics, photochemical and
photobiological dynamics, coherent x-ray scattering studies of non-equilibrium
dynamics, and x-ray induced structural and chemical dynamics. The objective of
the workshop will be to discuss the prioritization of these scientific
opportunities, discuss the required infrastructure to pursue these experiments,
and begin constructing research collaborations loosely organized around the
most promising opportunities.
Agenda: http://www-conf.slac.stanford.edu/ssrl-lcls/2007/lcls-lusi.htm
XANES Spectroscopy: Data Collection, Analysis, and Simulation
(contacts:
S. DeBeer George, debeer@stanford.edu; R. Szilagyi,
szilagyi@montana.edu)
The workshop will focus on experimental and theoretical aspects of XANES
spectroscopy in the soft to hard x-ray energy regions. In addition to
speciation information for solutions and mixtures, spectral features in the
XANES region can be related to the electronic and geometric structures of the
absorber by ligand field theory, molecular orbital theory, multiplet theory,
multiple-scattering theory, and band structure. The aim of the workshop is to
review the current state-of-the-art methods for interpreting XANES data, and
discuss the possibility of a more unified theory for the analysis of XAS edges.
Agenda: http://www-conf.slac.stanford.edu/ssrl-lcls/2007/xanes.htm
New Opportunities in Microfocusing
(contact: S. Webb,
samwebb@slac.stanford.edu)
The workshop will concentrated on the current expanding experimental techniques in hard x-ray microfocusing capabilities at SSRL, from the installation of microfocusing optics in hutch enclosures to the new full field hard x-ray microscope. Reviews will include the types of data that can be collected, including micro x-ray fluorescence maps, micro x-ray absorption spectroscopy, micro x-ray scattering, chemical imaging, and tomography. Presentations will review the beam lines at SSRL capable of conducting microfocusing experiments, and discuss the strengths and capabilities of the various techniques at each station. Experts are invited to give talks on the wealth of complementary information that can be obtained from the microscale observations. Agenda: http://www-conf.slac.stanford.edu/ssrl-lcls/2007/microfocusing.htm
New Opportunities in Imaging and X-ray Microscopy
(contacts: H.
Ohldag, hohldag@slac.stanford.edu; A. Scherz,
scherz@slac.stanford.edu)
State-of-the-art synchrotron x-ray sources as well as future sources like free electron lasers present excellent and unique opportunities for x-ray-based imaging techniques. Spatial resolution with x-rays can be obtained by using zone plate lenses in a scanning or full field microscope or by making use of the coherent properties of the x-rays in a coherent scattering or speckle setup. Both approaches can be used to obtain unique information about the chemistry, magnetism and structure of a complex sample. Due to the short wavelength of the x-rays and the pulsed nature of the x-ray source such facilities can provide an unprecedented combination of spatial and temporal resolution. It is therefore conceivable that in the future x-ray microscopy will evolve beyond its current status into an indispensable tool for a wide spectrum of scientific disciplines like condensed matter physics, geo- and environmental science, biology, soft matter science, chemistry and so on. The scope of this workshop is to identify scientific programs that will most directly benefit from such facilities and explore concepts for their realization. We will also address the current status of the field and explore possible future directions with particular focus on its suitability for LCLS. Agenda: http://www-conf.slac.stanford.edu/ssrl-lcls/2007/imagingXRayMicroscopy.htm
8.
Calling Interested Users to Serve on the SSRLUO Executive Committee
(contacts:
C.S. Kim, cskim@chapman.edu; R. Szilagyi, szilagyi@montana.edu)
 | |
2007 SSRLUOEC Chair | |
9.
SSRL Advisory Committees Convene in August
The SSRL Scientific Advisory Committee convened on August 7 to review and advise management on current and proposed programs at SSRL. The meeting began with an update by SSRL Director Jo Stöhr on operations and strategic planning. Updates were provided in several areas including: SPEAR3 and Beyond (Bob Hettel, Ingolf Lindau); New Science Made Possible with SPEAR3: Coherent Lensless Imaging (Andreas Scherz); X-ray Laboratory for Advanced Materials (Z. X. Shen); Photon Ultrafast Laser Science and Engineering (Phil Bucksbaum); and Structural Genomics Program Update (Britt Hedman, Ashley Deacon). Summaries were provided from three recent workshops: Structural Molecular Biology XAS Applications (Serena DeBeer George); Hard X-ray Scattering: Techniques in Materials and Environmental Sciences (Sam Webb); and STXM and X-ray Nanoprobe Capabilities and Needs for Geo-, Environmental, and Biological Sciences (Hendrik Ohldag). The SSRL Proposal Review Panel met on August 8 to determine ratings based on the peer reviews received for new proposals and program proposal extensions submitted during this last call for proposals, and the SSRL Structural Molecular Biology Advisory Committee met on August 6.
10.
Photon Science Job Opportunities
A number of positions are currently available at SSRL and LUSI.
Please refer to the Photon Science Job Openings page for more information about
these job opportunities.
http://photonscience.slac.stanford.edu/jobs.php
__________________________________________________________________________
SSRL Headlines is published electronically monthly to inform SSRL users, sponsors and other interested people about happenings at SSRL. SSRL is a national synchrotron user facility operated by Stanford University for the U.S. Department of Energy Office of Basic Energy Sciences. Additional support for the structural biology program is provided by the DOE Office of Biological and Environmental Research, the NIH National Center for Research Resources and the NIH Institute for General Medical Sciences. Additional information about SSRL and its operation and schedules is available from the SSRL WWW site.
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