SSRL Science Highlights Archive

Approximately 1,700 scientists visit SSRL annually to conduct experiments in broad disciplines including life sciences, materials, environmental science, and accelerator physics. Science highlights featured here and in our monthly newsletter, Headlines, increase the visibility of user science as well as the important contribution of SSRL in facilitating basic and applied scientific research. Many of these scientific highlights have been included in reports to funding agencies and have been picked up by other media. Users are strongly encouraged to contact us when exciting results are about to be published. We can work with users and the SLAC Office of Communication to develop the story and to communicate user research findings to a much broader audience. Visit SSRL Publications for a list of the hundreds of SSRL-related scientific papers published annually. Contact us to add your most recent publications to this collection.

SCIENCE HIGHLIGHT BANNER IMAGES

June 2005
Núria Aliaga-Alcalde, Serena DeBeer George, Bernd Mienert, Eckhard Bill, Karl Wieghardt, Frank Neese
Figure 1.

Iron metals oxidize to rust, losing electrons and gaining positive charge. Iron metals typically exist in an oxidation state of +2 or +3 (2 or 3 electrons less than a neutral iron atom). However, chemists have long thought that iron compounds with even higher oxidation states play important roles in enabling chemical reactions in metal-containing proteins.

X-ray Absorption Spectroscopy
BL9-3
May 2005
Uwe Bergmann
Image provided by Will Noel, The Walters Art Museum

An early transcription of Archimedes' mathematical theories has been brought to light through the probing of high-intensity x-rays at SSRL's BL6-2. The text contains part of the Method of Mechanical Theorems, one of Archimedes' most important works, which was probably copied out by a scribe in the tenth century. The parchment on which it was written was later scraped down and reused as pages in a twelfth century prayer book, producing a document known as a palimpsest (which comes from the Greek, meaning 'rubbed smooth again').

BL6-2
May 2005
Todd W. Lane, Mak A. Saito, Graham N. George, Ingrid J. Pickering, Roger C. Prince, François M.M. Morel
Figure 1.

Cadmium is known to be extremely toxic to mammals, and is generally viewed alongside mercury as an environmental problem and toxic element that is not used by nature in any way. A Brief Communication in the May 5 issue of the journal Nature shows that we need to revise our opinion of cadmium. The paper reports the purification and characterization of a previously unknown metalloenzyme from the marine diatom Thalassiosira weissflogii that specifically uses cadmium to achieve its biological function. This is the first cadmium enzyme that has been discovered.

X-ray Absorption Spectroscopy
BL7-3
April 2005
Peter S. Nico, Scott E. Fendorf, Yvette W. Lowney, Stewart E. Holm, Michael V. Ruby
Figure 1.

The chemically treated wood used for playgrounds, fences and decks appears to be less toxic than feared. The chromated copper arsenate (CCA) mix protects commercial outdoor grade lumber from weathering, but in recent years the public and the government realized the chemicals could be potentially risky to the many people exposed to the ubiquitous wood.

X-ray absorption spectroscopy imaging
BL4-3
April 2005
Jerome B. Hastings
Figure 1.

The Sub-Picosecond Pulse Source (SPPS) collaboration has published data from the first experiments ever using a linear accelerator-based femtosecond x-ray source. SPPS makes the world's shortest bunches of electrons in the SLAC linear accelerator and turns them into very bright pulses of x-ray light 1,000 times shorter than those made in synchrotron rings like SPEAR3. SPPS has many similarities to future free electron lasers like the Linac Coherent Light Source (LCLS) currently being built at SLAC.

March 2005
Donghui Lu, Kyle Shen, Zhi-Xun Shen
Figure 1.

High-temperature superconductors (HTSCs) operate in mysterious ways, but scientists are starting to understand their peculiarities by using a state-of-the-art spectroscopy system at SSRL. One of the biggest mysteries is how a material that starts as an insulator-which does not conduct electricity-can become a high-temperature superconductor after being doped with electric carriers. Researchers Kyle Shen and Donghui Lu (both SSRL), working in Zhi-xun Shen's group at SSRL and Stanford, looked at the evolution from insulator to superconductor by studying an HTSC material at different doping concentrations.

Angle-resolved photoelectron spectroscopy
BL5-4
February 2005
Aitor Hierro, Ji Sun, Alexander S. Rusnak, Jaewon Kim, Gali Prag, Scott D. Emr, James A Hurley
Figure 1.

The lysosome is the "digestive system" of an animal cell. Molecules taken up from the outside are sent to the lysosome to be broken up into a form that can be safely used by the rest of the cell. A network of membrane vesicles called the endocytic pathway moves cargo destined for the lysosome from the surface of the cell. One of the last steps before the cargo reaches the cell is the pinching-off of small vesicles into the center of a big vesicle.

Macromolecular Crystallography
BL9-2
December 2004
J. Lüning, W. F. Schlotter, J. Stöhr
Figure 1.

Researchers at the Stanford Synchrotron Radiation Laboratory (SSRL) and the German laboratory BESSY have crafted a versatile and stunningly effective technique to take x-ray images of tiny variations and lightning-quick changes in materials a thousand times smaller than the thickness of a strand of hair. Their work merits the cover of the December 16 issue of Nature. Researchers Jan Lüning of SSRL, Stefan Eisebitt of BESSY and their colleagues demonstrated the first direct imaging technique - lensless x-ray holography - that will work at the world's first x-ray free electron laser, the Linac Coherent Light Source (LCLS), slated to open at SLAC in 2009. Lensless imaging opens the door for "single shot" pictures at LCLS using just one pulse of x-ray light to capture a clear picture of ultra-fast action occurring on ultra-small length scale.

December 2004
Mark A. Breidenbach, Axel T. Brunger
Figure 1.

The Botox® face lifts and botulism disease are both caused by a neurotoxin from the bacterium Clostridium botulinum. The toxin, often described as the most lethal substance known, is a member of the clostridal neurotoxins (CNTs) group, which block muscle contractions. When injected into someone's face, the effect is a lessening of wrinkles. When ingested, the toxin paralyzes muscles, including those of the internal organs, causing sickness and death. The toxin is also used in medicine for conditions such as uncontrolled blinking, lazy eye, and involuntary muscle contractions.

Macromolecular Crystallography
BL9-2
November 2004
Myriam Perez De la Rosa, Gilles Berhault, Apurva Mehta, Russell R. Chianelli
Figure 1.

As oil prices rise, so will the market for cheaper forms of petroleum-based fuels. Cheaper petroleum contains more impurities, which will aggravate environmental problems, like heavier air pollution and acid rain. Purifying the fuel will alleviate the environmental harm. Sulfur impurities can be removed by treatment with catalytic materials such as Molybdenum disulfide (MoS2).

BL2-1

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