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.

August 2016
Hendrik Ohldag, Stanford Synchrotron Radiation Lightsource, Jason Robinson, University of Cambridge
Figure

Giant magnetic resistance  (GMR) is a quantum mechanical phenomenon observed in thin structures made of alternating metal layers having differing ferromagnetic properties. When the adjacent ferromagnetic layers of these multilayer materials are magnetized in parallel, there is little electrical resistance, but when magnetization is antiparallel, there is higher resistance. This property allows these materials to be used as magnetic sensors, and thin-film magnetic multilayers have been a popular topic of research. A team of researchers has tested the atomic properties of a variety of nickel and gadolinium (Ni/Gd/Ni) thin-film multilayers.

BL13-1
August 2016
André Hoelz, California Institute of Technology
Figure

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
July 2016
Ian A Wilson, The Scripps Research Institute, Koji Nakayma, Nagasaki University

Many bacteria, including many colonizing our own gut biomes, produce hair-like pili structures on their surfaces. There are various types of pili used for different purposes, like exchanging genetic information (conjugation), movement, and adhesion. A bacterium builds pilus through oligomerization of protein subunits. A group of scientists have determined the structure of a new type of pilus, which they named the type V pilus.

Macromolecular Crystallography
BL9-2, BL11-1, BL12-2
July 2016
Johanna Nelson Weker, jlnelson@SLAC.Stanford.EDU , William C. Chueh, wchueh@stanford.edu

Most portable electronic devices depend on lithium ion batteries for energy storage. The current capabilities of lithium ion batteries are insufficient for the requirements of emerging and growing industries, like electric cars and renewable energy storage. These industries require batteries that are longer-lived, smaller, lighter, and cheaper. One way to improve lithium ion batteries is to increase the charging cutoff voltage, which increases the energy that can be stored in the battery, but it leads to shortened battery life, called capacity fade. A team of scientists has discovered a new mechanism for capacity fade.

BL4-1, BL6-2c
June 2016
Serena DeBeer (Max Planck Institute for Chemical Energy Conversion, Cornell University), Ninian J. Blackburn (Institute of Environmental Health, Oregon Health & Sciences University), Vlad Martin-Diaconescu (Institut de Química Computacional i Catàlisi (IQCC), Universitat de Girona), Kelly Chacon (Reed College, Portland, Oregon)
figure

Protein enzymes can contain specific sites to bind copper atoms for a variety of purposes. Depending on the environment and role of the enzyme, different amino acid residues are employed to bind Cu(I).  Oxygenase enzymes employing Cu(I) often use both methionine (Met) and histidine (His) amino acids, while membrane transport proteins often use Met and not His. The identity and placement of the amino acids coordinating the Cu(I) atoms create different local environments, but it is unclear how this affects the Cu(I) atom to fulfill the role it serves for the enzyme or transporter.  A team of scientists has recently developed a new experimental approach to measure the local environmental effects on Cu(I) reactivity. 

X-ray emission spectroscopy
BL6-2
June 2016
Mary P. Ryan, Department of Materials and London Centre for Nanotechnology, Imperial College London
figure

Zinc oxide (ZnO) is used to coat optoelectronic technology, which includes components that create and/or detect light, x-rays, infrared, or other forms of radiation. When ZnO properly crystallizes, it creates a transparent conducting film. The performance of the film is compromised when there is disruption in nucleation and growth of ZnO. A team of scientists collaborated to study the process of electrodeposition of ZnO into films.

BL6-2c
May 2016
Jena Johnson, University of Colorado - Boulder
Figure 1

The element manganese can have complex interactions with the environment, depending on the prevailing conditions. Manganese(IV) is a strong oxidant but can also bind to environmental toxins and heavy metals, rendering them less harmful. Both geochemical and microbial processes affect the reactions of manganese(IV) in the environment. A team of researchers were interested in following the complicated reactions and mineral products produced during the reduction of manganese(IV) under different environmental conditions.

X-ray Absorption Spectroscopy
BL4-1, BL11-2
April 2016
Suhas Kumar, Hewlett Packard Labs
Figure

Theorized decades ago and currently being developed into useable technology, memristors are passive memory storage units especially useful for nanoelectronics. Memristors could replace the ageing flash memory in the near future. Memristors are usually made of a transition metal oxide layered between two metallic electrodes and are able to change their resistance in a non-volatile way between two states depending on an applied voltage.

Scanning transmission x-ray microscopy
BL6-2
April 2016
Mike Toney, Stanford Synchrotron Radiation Lightsource

Most solar panels use technology that employs a silver-silicon interface. Because silver is expensive and the lead used in the creation of this interface is toxic, researchers are interested searching for other materials that could work instead of these components. A team of scientists are working to understand the process involved in the silver-silicon contact formation so that alternatives that perform the same function can be found.

X-ray diffraction
BL7-2
March 2016
David R. Barbero, Umeå University
Figure 1

Current technologies of light emitting diodes (LEDs), photovoltaic systems (PVs), and other optical electronic devices typically use inorganic silicon-based semiconductors. However,  organic polymers could provide thinner, lighter and cheaper opto-electronic devices (like OLEDs and OPVs).

X-ray diffraction
BL2-1, BL11-3

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