Arsenic is a well-known toxin that can contaminate our drinking supplies. Understanding how arsenic finds its way into drinking water requires research into its interaction with environmental conditions that affect redox reactions, including interactions with iron, sulfur, and carbon.
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.
June 2018
X-ray Absorption Spectroscopy
BL4-1
May 2018
Local differences in a battery’s structure and chemistry can lead to problems with function, such local over-charging or under-charging, and can affect the ability to hold charge. Understanding these heterogeneities is important for engineering well-functioning batteries but they are difficult to measure and study. Scientists usually use either an electrochemical process or a chemical process to prepare materials when studying lithium ion battery heterogeneity at different state of charge. Both of these have flaws: the electrochemical process is close to real-life behavior but experiments may be complicated by structural complexity, and the chemical delithiation process creates a simpler structure but may not properly reflect real-world applications.
BL6-2c
May 2018
Organic semiconductors are crystals or thin films composed of carbon-based molecules bonded together though covalent “π-bonds” that provide conductivity. These organic semiconductors can be used for organic photovoltaic (OPV) devices, which show promise as an alternative to traditional solar cells with possible applications in building integrated photovoltaics. As with conventional semiconductors, such as silicon, doping organic semiconductors with specific impurities is needed to improve the electrical properties. One effective method for doping, using 12-molybdophosphoric acid hydrate (PMA), was discovered recently but requires the use of the unstable solvent nitromethane.
Grazing incidence x-ray absorption spectroscopy
BL11-3
April 2018
Polymorphism is a fascinating natural phenomenon across many areas of materials science – from small molecules in chemistry, to minerals in geology, to drugs in pharmaceutical industry, to solid-state materials in electronics. High-density polymorphs with unique properties, such as a transparent insulating form of sodium (1) are routinely synthesized under compressive strain at very high pressure. In contrast, applying large negative pressure is very difficult, because large tensile strain usually causes materials to rupture. This logically leads to a question: how could negative pressure polymorphs be synthesized and what functional properties would such unusual materials have?
X-ray scattering
BL11-3
March 2018
CoCrMo-based metal-on-metal hip implants were introduced, particularly for younger patients, due to their superior wear resistance and theoretical mechanical advantages over other hip implant materials (especially the most commonly used metal-on-polyethylene). However, these CoCrMo-based implants suffered an unexpectedly high failure rate1 raising concerns over their safety, and leading to considerable attention in the literature on explaining the reasons behind their failure.
BL6-2c
March 2018
Influenza also called “Flu” is a disease of the human respiratory tract caused by influenza virus. Each year, seasonal influenza can cause severe and widespread disease in the human population and cost billions of dollars to the world economy. Such a problem occurred this year with the influenza A H3N2 virus. Currently available remedies to tackle influenza are the seasonal trivalent or tetravalent vaccines or FDA-approved antiviral drugs, such as Tamiflu and Relenza. Since influenza viruses are constantly mutating and circulating as new strains in the human population, influenza vaccines need to be updated each year. Furthermore, the efficacy of these currently available front-line drugs are declining due to the relentless evolution in the influenza virus strains (1-3).
Macromolecular Crystallography
BL12-2
March 2018
Imagine being born with severe muscle weakness. Several of your joints are contracted, your spine is abnormally curved, and you have an opening in the roof of your mouth, affecting your hearing, breathing and speech. On top of that, if you undergo surgery, you may die from a serious reaction to the anesthetics that causes your body temperature to rise to lethal levels. This happens to people that have Native American Myopathy (NAM), a disorder first described for the Lumbee Native Americans in North Carolina, where about 1 in 5000 individuals is affected. The cause for the disorder is genetic: a mutation in a gene known as stac3.
Macromolecular Crystallography
BL9-2
February 2018
Chromatin is the complex of DNA and proteins that comprises the physiological form of the genome. Non-covalent interactions between DNA and histone proteins are necessary to compact large eukaryotic genomes into relatively small cell nuclei. The nucleosome is the fundamental repeating unit of chromatin, and is composed of 147bp of DNA wrapped around an octamer of histone proteins: 2 copies of each H2A, H2B, H3 and H4.
Biological Small-angle X-ray Scattering (BioSAXS)
BL4-2
February 2018
Li-ion batteries (LIBs) are key components of portable electronic devices, as well as in electric vehicles, military and medical equipment, backup power supplies, and even grid storage. However, the energy storage capacity and rate capability of current LIBs is still too low to meet the increasing demand of key markets. For the latter, the properties of the electrolyte-electrode interface play a decisive role.
X-ray reflectivity
BL7-2
January 2018
Since the discovery of unconventional high-temperature superconductivity (HTSC) in cuprates, one of the central questions in high Tc research is the nature of the “normal state” which develops into HTSC. As one of the pursuits of normal state properties, the recent observation of charge density wave (CDW) order is expected to shed light on the nature of the competing phases in high Tc cuprates. For this reason, CDW order in hole-doped cuprates has been actively studied by various experimental techniques such as neutron and x-ray scattering, scanning tunneling microscopy (STM), nuclear magnetic resonance (NMR), quantum oscillation, and ultrasound experiments. Among those techniques, x-ray scattering uniquely characterizes the spatial arrangement and strength of the charge density wave.
Angle-resolved photoelectron spectroscopy
BL5-2, BL13-3
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