In the atmosphere, methane is a much more potent greenhouse gas than carbon dioxide, trapping 20 times more heat. As a fuel, methane burns cleanly, producing less carbon dioxide per unit of heat than other fuels. For these reasons, understanding methane production is immediately important.
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.
October 2009
BL9-3
September 2009
The arrangement of atoms in molecules and complexes that include atoms with many interacting electrons can be hard to predict. The Jahn-Teller (JT) effect sometimes predicts a geometric distortion of the oxygen octahedra surrounding transition metals such as Mn, Co, and Cu. In this model, for certain ground state configurations of the electrons on the metal atom, the total electronic energy can be reduced if the surrounding oxygen octahedra adopt a distorted structure that might seem unstable. The JT distortion is seen in many copper complexes, produces a metal-insulator transition in many manganites, and was predicted to affect the shape of the oxygen octahedra about Co (CoO6) in La1-xSrxCoO3.
BL10-2
September 2009
The water molecule, H2O, has deceptively simple structure, but contains all the prerequisites for building complexity. The oxygen atom has a greater affinity for electrons and pulls them away from the hydrogens making them slightly positive. On the back side of molecule oxygen has a lone pair - electrons that do not assist in binding the hydrogens in the molecule, but to which the hydrogens of another water molecule can be attracted to form a so-called hydrogen bond (H-bond). Hydrogen bond is much weaker than the bonding inside water molecule, but it is still strong enough with the possibility to make from one up to four H-bonds per water molecule. The network connected by H-bonds between water molecules makes liquid water so special compared to other normal liquids with about 66 anomalies, e.g.
BL4-2, BL6-2
September 2009
You have probably never seen a bacteria pop. Yet, as solution-filled balloons, bacterial cells are susceptible to changes in pressure. For example, microbes entering a fresh water solution from a salt solution would quickly succumb to death by swelling due to water rushing into the cells due to osmotic pressure differences. Bacteria do not pop because they are able to sense and respond to changes in pressure through mechanosensitive channels that transverse their membranes. These gates are like pressure relief valves, opening to ease pressure and closing when balance is restored.
Macromolecular Crystallography
BL12-2
August 2009
Recent advances in materials research are setting the stage for macroelectronics to have a disruptive effect on everyday technology. While microelectronics focuses of the miniaturization of electronic devices (think of the shrinking iPod), macroelectronics is the replication and integration of microelectronic devices onto large areas such as display backplanes (big screen TVs and electronic billboards), large-area photovoltaics (flexible solar cells) and radio frequency ID tags. One class of materials that has demonstrated great promise as the semiconducting layer in these macroelectronics devices is polymer semiconductors, which allow for potentially inexpensive manufacturing from solutions.
X-ray diffraction
BL7-2, BL11-3
August 2009
The emergence of drug-resistant microbes represents a major impediment in the treatment of bacterial infections. Resistance to first-choice drugs has become problematic for respiratory infections, AIDS, tuberculosis, malaria and diarrheal diseases, which are top killers among infectious agents. When second- and third-choice drugs succumb to similar resistance, treatment options become dire. As such, a major scientific priority in health-related research and medicine is to identify new antimicrobial targets and to develop novel drugs that keep infectious diseases in check according to global demand.
Macromolecular Crystallography
BL7-1
July 2009
Nothing seems to move as fast as the field of consumer electronics. A browse through a technology store reveals the dizzying array of space-age -seeming products like flat screen TVs, touch screen phones, and mp3 players. A new development in electronics is on the horizon, one that may bring us roll-up flat screens and high-definition display clothing. These will be made possible using the thin and energy efficient organic light emitting diodes (OLEDs), which are based on organic semiconductor technology. Both a desire for less expensive, more convenient technologies and a concern for energy conservation have heightened interest in the field of organic semiconductors.
BL11-3
July 2009
Solar panels contain a number of solar cells that convert light into electricity. Solar cells are traditionally made of crystalline silicon, which presently have 15-20% efficiency in conversion of light into electricity. However, these traditional cells are bulky and have high production costs that can take 5-7 years of solar panel operation to recover. Using solar cells made from organic materials could lower their production costs. This would lessen the time it takes for solar panels to generate more energy than consumed during production and would also result in more widespread application of solar energy.
BL2-1, BL7-2, BL11-3
June 2009
The world's animals depend on plants, plants depend on photosynthesis, and photosynthesis depends on iron. Despite a relative abundance of this element, iron in a form useable by plants can be rare. Living organisms require soluble iron, which generally comes from environments in flux since iron settles into stable minerals unavailable to life. Since around 30-40% of oceans are iron-limited, understanding the sources of soluble iron is critical to understanding oceanic ecosystems, which are responsible for taking significant amounts of carbon out of the air.
X-ray Absorption Spectroscopy
BL2-3, BL11-2
June 2009
Diatoms, unicellular algae that exist almost anywhere there is water, have recently attracted attention as potential thwarters of climate change. Diatoms go through cycles of blooms, where they grow and multiply rapidly near the ocean's surface. Scarcity of a nutrient will trigger the end of a bloom and the algae sink, taking with them large amounts of sequestered carbon from the air to the bottom of the ocean. Because iron is a limiting nutrient in about 30-40% of the world's oceans, some researchers propose that artificially enriching iron in oceans would promote diatom growth and carbon dioxide capture similar to the hypothesized scenario that occurs during glacial periods when iron input into the ocean is higher.
Macromolecular Crystallography
BL7-1, BL9-2
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