Previous Editions


SSRL Headlines Vol. 8, No. 2  August, 2007


Contents of this Issue:

  1. Science Highlight — The Chemical Form of Mercury in the Fish We Eat
  2. Science Highlight — How Stents Take the Strain
  3. 2007 Spicer Young Investigator Award to be Presented to Hugh Harris
  4. Jessica Vey to Receive 2007 Klein Award
  5. Register for 2007 SSRL/LCLS Users' Meeting and Workshops, September 28-October 3
  6. Learn About SR Techniques or Brush Up Your Skills at September 30 Workshop
  7. Several Concurrent Workshops Offered on October 3
  8. Calling Interested Users to Serve on the SSRLUO Executive Committee
  9. SSRL Advisory Committees Convene in August
  10. Photon Science Job Opportunities

1.  Science Highlight — The Chemical Form of Mercury in the Fish We Eat
       (contact: Y. Arai,

Trophic transfer diagram
Mercury toxicity is an environmental concern in diverse aquatic systems because methylmercury enters the water column in a number of ways and then biomagnifies through food webs. Piscivorous fish at the top of many freshwater food webs can then extend that trophic transfer and potential for neurotoxicity to wildlife and humans. Mining activities, particularly those associated with the San Francisco Bay region, can generate both point and non-point mercury sources. Largemouth bass and hybrid striped bass from Guadalupe Reservoir (GUA), California and Lahontan Reservoir (LAH), Nevada were analyzed at SSRL's Beam Line 9-3 to determine predominant chemical species of mercury accumulated by high-trophic-level piscivores that are exposed to elevated mercury in both solution and particulate phases in the water column. Both GUA and LAH are affected either directly or indirectly by the legacy of gold and silver mining in the Sierra Nevada during the 19th century.

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:

2.  Science Highlight — How Stents Take the Strain
       (contact: A. Mehta,

Maps of the deviatoric strain of the B2 austenite along the vertical y
axis from x-ray diffraction analysis.
Maps of the deviatoric strain of the B2 austenite along the vertical y axis (eyy) from x-ray diffraction analysis.
Endovascular stents made from superelastic Nitinol are a major component in the fight against heart disease. But in order for stents to be used safely for prolonged periods in human arteries, it is important to accurately characterize stress/strain distributions in such stents, which govern how they deform and fracture. SSRL scientists working at Lawrence Berkeley National Laboratory's Advanced Light Source Beam Line 7.3.3 have taken the first direct in situ x-ray micro-diffraction measurements of the local strain field of a stent-like Nitinol component subjected to realistic stresses.

Because of unique mechanical characteristics and excellent biocompatibility, Nitinol is used as self-expanding endovascular stents to scaffold diseased peripheral arteries. Such stents were initially designed to provide sufficient scaffolding force to hold open vessels, yet provide enough elasticity to withstand pulsing strains from the cardiac cycle. Many studies indicate that these stents perform this primary function quite well. More recent in-depth studies, however, indicate that when stents are used in peripheral arteries in more active patients they sometime break.

The SSRL team used a 1x1 micrometer white x-ray beam to investigate deformation of a stent-like component under moderate to high deformation conditions. Micro-diffraction measurements indicate that state-of-the-art commercial finite-element models used to predict local strain fields are sufficient up to 3% deformation. However, there are significant discrepancies between measured and calculated strains at larger displacements such as seen by superficial femoral arteries (SFAs) as the leg is bent from an extended position. The results show that a much better understanding of how superelastic Nitinol accommodates high deformation is needed.

To learn more about this research recently published in Advanced Materials see the full scientific highlight at:

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.

4.   Jessica Vey to Receive 2007 Klein Award

       —By Ken Kingery

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.

"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
      (contact: C. Knotts,

Users mtg logo
There are several very exciting events planned for the upcoming SSRL/LCLS Users' Meeting, beginning with a special symposium on September 28-29 to look into the future of x-ray science. The main Users' Meeting, on October 1-2, will feature presentations on recent developments and new opportunities in structural biology and spectroscopy, material and environmental science, ultrafast science and LCLS instrumentation. A special keynote presentation will be given by Nobel Laureate Professor Roger Kornberg. Several focused workshops will be held on Synchrotron Techniques, XANES Spectroscopy; Microfocusing; Imaging and X-ray Microscopy; and Scientific Opportunities for Studying Laser Excited Dynamics at the LCLS.

6.   Learn About SR Techniques or Brush Up Your Skills at September 30 Workshop

      (contacts: K. McFarlane Holman,; A. Doran,

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.

7.   Several Concurrent Workshops Offered on October 3

Scientific Opportunities for Studying Laser Excited Dynamics at the LCLS, October 3
      (contact: K. Gaffney,

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.

XANES Spectroscopy: Data Collection, Analysis, and Simulation
       (contacts: S. DeBeer George,; R. Szilagyi,

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.

New Opportunities in Microfocusing
       (contact: S. Webb,

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:

New Opportunities in Imaging and X-ray Microscopy
      (contacts: H. Ohldag,; A. Scherz,

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:

8.   Calling Interested Users to Serve on the SSRLUO Executive Committee
      (contacts: C.S. Kim,; R. Szilagyi,

C. Kim
2007 SSRLUOEC Chair
Your help is needed to identify users who may be interested in serving on the SSRL Users' Organization Executive Committee (SSRLUOEC) - and you can nominate yourself! We are currently soliciting nominations for two positions on the SSRLUOEC in the following disciplines: environmental science and macromolecular crystallography. This is a particularly exciting time in the life of the lab, and users are encouraged to more actively participate in strategic planning opportunities for SSRL (planning for operations and future developments such as new microfocusing and imaging capabilities, ultrafast science, preparations for top-off injection and 500 mA operations). In addition to representing user interests to management and advisory committees, the SSRLUOEC promotes user science to a broader audience; coordinates advocacy activities with representatives from other DOE user facilities; organizes the annual users' meeting and workshops; and presents awards to recognize scientific or technical accomplishments (Lytle Award, Klein Professional Development Award, Spicer Young Investigator Award, Outstanding Graduate Student Poster Awards). Take a few minutes to think about individuals who might be available to meet a few times a year to participate in these important activities, and forward your nominations to Cathy Knotts by September 4.

9.   SSRL Advisory Committees Convene in August

      (contact: J. Stöhr,

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.


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.


To leave the SSRL-HEADLINES distribution, send email as shown below:

To: LISTSERV@SSRL.SLAC.STANFORD.EDU Subject: (blank, or anything you like)

The message body should read


That's all it takes. (If we have an old email address for you that is forwarded to your current address, the system may not recognize who should be unsubscribed. In that case please write to and we'll try to figure out who you are so that you can be unsubscribed.)

If a colleague would like to subscribe to the list, he or she should send To: LISTSERV@SSRL.SLAC.STANFORD.EDU and use the message body


SSRL Welcome Page | Research Highlights | Beam Lines | Accel Physics
User Admin | News & Events | Safety Office


Last Updated: 30 AUG 2007
Content Owner: L. Dunn
Page Editor: L. Dunn