February 2017
Peter J. Chung, University of Chicago, Cyrus R. Safinya, University of California, Santa Barbara
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)
BL4-2
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
BL12-2
January 2017
Hans-Georg Steinrück, SSRL, Chuntian Cao, Stanford University, Michael F. Toney, SSRL
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
BL2-1
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
BL13-1
October 2016
Yijin Liu, Stanford Synchrotron Radiation Lightsource, Apurva Mehta, Stanford Synchrotron Radiation Light Source
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
BL6-2
October 2016
Hongping Yan, Stanford Synchrotron Radiation Lightsource, Xiaodan Gu, Chemical Engineering, Stanford University
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.
BL7-2
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)
BL4-2
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.
BL11-3
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.
BL6-2c
August 2016
André Hoelz, California Institute of Technology
The nucleus, which contains the DNA in eukaryotic cells, has pores in the surrounding double membrane that actively transport biologically important molecules in and out. Controlling these processes is done by a macromolecular protein machine called the nuclear pore complex (NPC). The human NPC is very large, composed of around 1000 proteins of 34 different types, which assemble into a structure with eight-fold symmetry. Because of the important role the NPC plays in our cells and its role in various diseases, such as viral infections, cancers, and neurodegenerative diseases, researchers would benefit from a high-resolution structure of the NPC that reveals the ordering of all of its ~10 million atoms. A team of scientists has accomplished exactly this.
Macromolecular Crystallography
BL12-2
