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.

October 2018
Figure 2

The central dogma of molecular biology posits that the genes in our DNA are transcribed (or “copied”) into messenger RNAs (mRNA), which are then translated (or “read-out”) into the proteins that make up our cells and tissues. Control of gene expression is critical to human health and development.. One major mechanism of regulation involves very small RNAs called microRNAs (miRNAs). miRNAs regulate genetic information post-transcription by binding to mRNAs and preventing translation into proteins. It is estimated that about half the protein-coding genes in the human genome are regulated by a miRNA, and breakdown of miRNA systems is increasingly associated with human disease, including many forms of cancer. A central question in miRNA biology is: how do these tiny RNAs effectively regulate mRNAs, which are hundreds or even thousands of times their size?

Macromolecular Crystallography
BL12-2
October 2018
Y. He, Stanford University, Z.-X. Shen, Stanford University / SIMES
Figure 2

Materials that act as superconductors at higher temperatures (as high as -70°C) are a subject of intense research, due to their use in magnets and quantum devices, including advanced medical and scientific instruments. Interactions of many quantum-level variables in superconducting materials make these systems difficult to model. The Hubbard Model, proposed in 1963 to explain the behavior of correlated electrons in solid materials and 20 years later applied to high-temperature superconducting materials, has been favored due to its relative simplicity along with limited experimental verification. This model focuses on the exclusively electronic variables for superconductivity, completely neglecting atomic-scale vibrations (termed phonons) of the lattice of the material. A team of scientists has challenged the assumption that phonons do not impact high temperature superconductivity through studying a cuprate material.

Angle-resolved photoelectron spectroscopy
BL5-4
September 2018
Figure

Nanotechnology, which focuses on materials that measure between 1 and 100 nanometers in at least one dimension, is being applied to diverse areas of research including medicine, electronics, and biology. Yet it is unclear how these engineered nanomaterials might interact with and affect environments and ecosystems.

X-ray Absorption Spectroscopy
BL11-2
August 2018
Feng Lin, Virginia Tech, Yijin Liu, Dennis Nordlund and Dimosthenis Sokaras, Stanford Synchrotron Radiation Lightsource
Figure 1

Lithium ion batteries are widely used in electronic devices and vehicles because of their high energy density. Unfortunately, lithium is not an abundant element on Earth, so demand is mounting for an alternative battery that has high energy density but made with more sustainable materials.

X-ray microscopy
BL4-1, BL6-2c
August 2018
Yijin Liu and Simon Bare, Stanford Synchrotron Radiation Lightsource, Dante Simonetti, UCLA

Hydrogen sulfide (H2S) is a poisonous and corrosive gas created in industrial and natural systems. Copper oxide (CuO), a crystalline solid, can be used to clean H2S from emissions by forming various copper sulfide species, a reaction that is thermodynamically favorable but often does not go to completion in industrial applications.

X-ray Absorption Spectroscopy
BL2-2, BL4-3, BL6-2c
July 2018
Bor-Rong Chen and Laura Schelhas, Stanford Synchrotron Radiation Lightsource, Wenhao Sun, Lawrence Berkeley National Laboratory
Figure 1

Metastable materials are materials that exist in their higher-energy configurations. They will eventually transform into their lowest energy form, given a certain amount of time. The classic example is diamond, which given enough time will change into graphite. They can have desired functionalities that make them useful in a variety of applications, such as in electronics, batteries, and catalysts. However, making metastable materials is not an easy job.

X-ray scattering
BL11-3
July 2018
Zamyla Morgan Chan, Harvard University
Figure 1

The more widespread use of solar electricity is not currently limited by the technology for generating energy from sunlight but by the storage of that energy, so that it can be used when needed.  Converting water to O2 and H2 via the oxygen evolution reaction (OER) is a fossil fuel free way to store energy for later use; catalysts that improve the efficiency of OER are being sought. Manganese oxide (MnO2) films are good catalysts of OER, with additional benefits of being acid-stable and earth abundant.

X-ray Absorption Spectroscopy
BL4-1
June 2018
Britta Planer-Friedrich, Bayreuth University, Germany, Johannes Besold, Bayreuth University, Germany

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.

X-ray Absorption Spectroscopy
BL4-1
May 2018
Yijin Liu, SSRL, Dennis Nordlund, SSRL, Marca Doeff, LBNL
Figure 1

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
Figure 1

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

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