SSRL Science Highlights Archive

Approximately 1,600 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.

March 2017
David Buchwalter, North Carolina State University, Dean Hesterberg, North Carolina State University

Coal-ash spills in Tennessee and North Carolina rivers have prompted concerns that toxic trace elements like arsenic could be concentrated in the food web to potentially affect humans. At the base of these freshwater food webs are periphyton biofilms, which contain a complex ecosystem of micro-organisms including bacteria, fungi, diatoms, and algae. Such biofilms can concentrate trace elements hundreds to thousands of times. To investigate whether arsenic concentrated in biofilms is propagated up the food chain, a team of scientists has studied the bioavailability of arsenic to organisms that feed on the periphyton biofilms.

February 2017
Peter J. Chung, University of Chicago, Cyrus R. Safinya, University of California, Santa Barbara
Figure 1

Microtubules (MTs) are sub-cellular structures made of the protein tubulin. They have important roles in moving organelles around the cell and in chromosome segregation before cell division. MTs can exist in two states, either a dynamic state of growing and shrinking MTs or a stable state. MTs can also form complex bundles that can be found in neuronal axons. The neuronal protein Tau helps facilitate this process and has been implicated in some neurodegenerative disorders like Alzheimer’s disease. Yet Tau’s exact role in MT formation and bundling is unclear: different experiments (both in vivo and cell free) have shown Tau to mediate either attractive or repulsive forces between MTs.


Biological Small-angle X-ray Scattering (BioSAXS)
January 2017
Jennifer Cochran, Stanford University, Amato Giaccia, Stanford University

The presence of the receptor tyrosine kinase Axl on tumor cells is correlated with disease severity and thus is an important oncology target. Developing inhibitors to Axl has been met with limited success due to the tight affinity with which Axl binds its ligand, growth arrest-specific 6 (Gas6). Researchers have engineered a soluble “receptor decoy,” called MYD1, based on Axl’s ligand-binding domain, that binds Gas6 even more tightly than Axl does.  

Macromolecular Crystallography
January 2017
Hans-Georg Steinrück, SSRL, Chuntian Cao, Stanford University, Michael F. Toney, SSRL
Fig 1

Lithium ion batteries are critical to many portable consumer electric devices, but they still do not have a high enough energy storage capacity for some applications, such as electric cars. Researchers and engineers are working to improve these batteries by changing the materials used. Using silicon as the anode has been promising, showing up to 10-fold higher capacity than the currently used graphite-based anode material. However, commercialization is still limited because the silicon expands and contracts dramatically when charged and discharged, causing cracking and pulverization that limit the battery lifetime.

X-ray reflectivity
December 2016
Hendrik Ohldag, Stanford Synchrotron Radiation Lightsource, Jun-Sik Lee, Stanford Synchrotron Radiation Lightsource

Over the past three years a team of researchers has worked to understand the thermodynamic transitions in the antiferromagnetic ferroelectric BiFeO3 with La substitutions in relation to a new strategy for finding the ultimate magnetoelectric single phase material. The researchers made the striking finding that structural, ferroelectric, and magnetic phases evolve due to strong spin-lattice coupling, thereby producing a multiferroic triple phase point where three competing multiferroic phases merge.

Scanning transmission x-ray microscopy
October 2016
Yijin Liu, Stanford Synchrotron Radiation Lightsource, Apurva Mehta, Stanford Synchrotron Radiation Light Source
DBScan Figure

Rare earth magnetic materials have many applications, such as MRI scanners, Maglev trains, and electric vehicles. Scientists are researching improvements to these magnets through optimizing the component materials. Taking a different approach, a team of scientists have studied the effects of nano-scale heterogeneity in the chemistry and structure of Nd2Fe14B, a very strong and widely-used rare earth magnet. 

X-ray microscopy
October 2016
Hongping Yan, Stanford Synchrotron Radiation Lightsource, Xiaodan Gu, Chemical Engineering, Stanford University
Figure 1

Researchers are evaluating the use of organic semi-conductive polymers instead of inorganic semiconductors for use in solar cells. Polymer semiconductors are more flexible and more easily applied, which could allow for more uses and lower production costs. Unfortunately, solar cell devices made of these organic materials tend to have less power conversion efficiency, largely due to the way the donor and acceptor molecules are arranged in the bulk heterojunction (BHJ) structures.

October 2016

RNA molecules, often bound to protein in complexes, play essential roles in many basic cellular processes in all life. Like with proteins, often these roles depend on the distinct 3-dimensional shapes the RNA molecules adopt. While much research has been done using traditional biophysical techniques to determine the predominant structure of many RNA folds, less is known about the array of shapes a certain type of RNA can adopt and how this ensemble of form affects function. 

Biological Small-angle X-ray Scattering (BioSAXS)
September 2016
Laura Schelhas, Stanford Synchrotron Radiation Lightsource, Wladyslaw Walukiewicz, Lawrence Berkeley National Laboratory

In materials science, the creation of composites by mixing of materials with different properties can lead to a new set of properties. To create a new type of nanocomposite material for semiconductors, a team of scientists chose to combine CdO and SnTe, materials with disparate optoelectric properties, one acting as an n-type (electron-rich) and the other a p-type (hole-rich) semiconductor.

September 2016
Yijin Liu, Stanford Synchrotron Radiation Lightsource, Xiqian Yu, Brookhaven National Laboratory / Institute of Physics, Chinese Academy of Sciences, Xiao-Qing Yang, Lawrence Berkeley National Laboratory

The continuing development of better lithium-ion batteries, which are common in consumer electronics, depends on improvements in the batteries’ chemical materials. Over the charge/discharge cycle of the battery, the electrochemistry and morphology of the material change, which can cause steric stresses and defects, leading to decreased battery performance. Modifications of the lithium compounds used at the cathode can help the batteries hold more charge and keep charge better over many charge/discharge cycles.



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