Currently, more than 1/6th of the people in the world lack safe and clean water. Population shifts, global warming and many other global changes will make this shortage even more critical in the coming years. Solutions to this problem lie in the development of new, energy-efficient means of purifying water. One of the traditional purification technologies—called membrane-based reverse osmosis—is very energy intensive, and this is spurring a flurry of activities into creating new, energy-efficient materials. Among the most promising of these materials are carbon nanotubes. A related material, activated carbon—basically carbon treated at extreme temperatures to achieve a high degree of microporosity and functionality-has been used for a century or more to filter water, and soak up unwanted compounds. However, the precise arrangements of the atoms that give rise to these purifying properties have mostly remained a mystery.
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.
Phytoplankton are microorganisms that live in the ocean surface waters and are important because they act as lungs for the planet, consuming carbon dioxide and producing oxygen. Phytoplankton account for an astounding 50% of the total biological uptake (or sequestration) of carbon dioxide annually. Understanding the factors that affect the growth of phytoplankton, is therefore of particular importance for this carbon sequestration, since the amount of released carbon dioxide continues to increase world-wide.
DNA is softer and stretchier than previously believed, at least on the short length scales of up to 20 base pairs. This finding is the result of a recent study conducted in part at SSRL's biological small-angle x-ray scattering Beam Line 4-2 by a team of researchers from Stanford University. The results were published in the October 17 edition of the journal Science.
Using macromolecular crystallography techniques, the team solved the structure of a protein on the Ebolavirus's surface, called glycoprotein GP, in complex with a rare antibody identified in a human survivor. The glycoprotein-antibody complex proved especially challenging to crystallize and subsequently, to yield well-diffracting crystals. The team grew ~50,000 crystal samples and screened 800 of the largest, using in part the highly-automated robotics hardware and software at the SSRL beam lines, before finding a sample that would diffract to 3.4 Angstroms.
Scientists are one step closer to understanding a piece of the machinery involved in DNA transcription and repair, thanks to work done in part at the SSRL macromolecular crystallography Beam Line 11-1. The team, led by The Scripps Research Institute researcher John Tainer, and colleagues worked out the structure of an important enzyme call XPD, a member of the helicase family of enzymes, found in all living organisms. The results were published in the May 2008 edition of the journal Cell.
Iron plays an integral role in many biochemical processes essential for life. However excess iron leads to the production of highly reactive hydroxyl radicals by Fenton chemistry (1). These free radicals are deleterious to cells as they react indiscriminately with proteins, DNA and lipids. Hence, iron homeostasis is a highly regulated process and is critical to human health (2). Disorders in iron metabolism, are however, surprisingly common. Iron deficiency affects more than one billion people worldwide (3,4), while iron overload disorders (hereditary hemochromatosis) are among the most frequent single gene disorders in humans. For example occurrence of disease associated allele, HFEC282Y, is as high as 10% in individuals of Northern European descent (5).
The recent discovery of superconductivity in iron-based layered compounds known as iron oxypnictides has renewed interest in high-temperature superconductivity. Now, SLAC and Stanford researchers, using SSRL's angle resolved photoemission spectrometer at Beam Line 5-4, have furthered the quest to understand this iron-based compound. In a recent paper published in Nature, SSRL scientist Donghui Lu, with colleagues at SSRL and Stanford, reported on the mechanism behind the superconductivity of a lanthanum-oxygen-iron-phosphorus (LaOFeP) compound, one of the new iron-based superconducting materials.
A team of researchers working at SSRL Beam Line 13-3 have devised an imaging technique that combines methods from traditional x-ray crystallography and x-ray holography, circumventing one of the major technical hurdles associated with capturing detailed images of non-periodic structures. The results were published in the August 15 edition of Physical Review Letters.
Panoramic images are captivating in any form, with their wide field of view and extremely high resolution. Now, SSRL scientists have demonstrated a new x-ray holographic technique for imaging wide areas of a nanoscale sample without losing resolution. The results were published in the November 2007 edition of the journal Optics Letters.
Using SSRL's beam line 5-4, researchers from Fudan University in Shanghai and SSRL have worked out the mechanism behind the formation of charge density waves in 2H-structured transition metal dichalcogenides (2H-TMD's). The results were published in the November 21, 2007 edition of Physical Review Letters.
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