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

July 2005
Scott Pegan, Christine Arrabit, Wei Zhou, Witek Kwiatkowski, Anthony Collins, Paul Slesinger, Senyon Choe
Figure 1.

Ion channels in our cells generate the nerve impulses that enable the heart to beat, the body to move, and sensation and thought to occur. Scientists from the Salk Institute for Biological Studies have identified a tiny flexible gateway that controls the rapid-fire opening and closing of a family of ion channels through which nerve-triggering potassium ions flow in and out of cells of the body. Malfunctions in the channels leads to several human diseases, including epilepsy, cardiac arrhythmias and muscle disorders.

Macromolecular Crystallography
BL9-2
July 2005
Tomohisa Kuzuyama, Joseph P. Noel, Stéphane B. Richard
Red

Using x-ray diffraction data collected on Beam Line 9-2 at SSRL, and other beam lines at the ESRF and BNL, scientists at The Salk Institute for Biological Studies discovered the three-dimensional structure of a protein that bacteria use to make biologically active compounds. By effectively engineering this protein, scientists may be able to create new drugs with therapeutic properties.

Macromolecular Crystallography
BL9-2
June 2005
Christopher S. Kim, James J. Rytuba, Gordon E. Brown, Jr.
Figure 1.

Mercury (Hg) is a naturally occurring element that poses considerable health risks to humans, with high exposure levels resulting in damage to the brain, heart, kidneys, lungs, and immune system. Young children and unborn babies are particularly vulnerable to mercury, which can affect their nervous systems and impair their neurological development. As a result, mercury is one of the most strictly regulated pollutants by the Environmental Protection Agency (EPA), which controls mercury emissions from coal-fired power plants and issues consumption advisory warnings for various types of fish, the primary route of mercury exposure to humans

BL4-3, BL11-2
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

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