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.

SCIENCE HIGHLIGHT BANNER IMAGES

August 2020

In the 1950’s and 60’s a poisoning occurred in Minamata Japan.  In addition to the people, the local cat population was affected with what was called “Dancing Cat Disease” and shortly thereafter neurological signs and symptoms became more prominent in people.  The sickness became known as Minamata Disease.  Eventually it was shown to be a form of organic mercury poisoning.  During the episode, pregnant women who were minimally or not obviously affected delivered infants who had neurological disorders such as seizures, microcephaly, and cerebral palsy.

The local company that caused the pollution employed a physician who played a role in determining the cause.  He found that cats fed chemical effluent from the factory quickly developed signs similar to those seen in people with Minamata Disease. He preserved samples of brain tissue from one of the cats, and remarkably, these samples still exist. An international team of researchers used sophisticated modern techniques to analyze these samples and determine the chemical form of mercury within the tissue.

X-ray Absorption Spectroscopy
BL6-2b, BL7-3
August 2020
Ian Wilson, The Scripps Research Institute

The COVID-19 pandemic triggered by the SARS-CoV-2 coronavirus is causing health and economic havoc on a global scale requiring the development of an effective vaccine and therapeutics. Spike proteins found on the viral surface of SARS-CoV-2 attach to human cells to gain entry. Neutralizing antibodies which target these same spike proteins of the CoV-2 virus would effectively block viral entry.

A research team reviewed data on ~300 antibodies from convalescent patients that target SARS-CoV-2 and found that the gene IGHV3-53 was the most frequently used to produce these antibodies.

Macromolecular Crystallography, Microbeam experiments
BL12-1
June 2020
Jeannine Brady, University of Florida, Gerald Stubbs, Vanderbilt University
Figure 1

Amyloid, composed largely of mis-folded proteins that form insoluble fibrillar aggregates, is important to many human diseases including Alzheimer’s.  Tooth decay also features amyloid-forming proteins, but in this case it is not mis-folded human amyloid proteins but bacterial proteins that are not mis-folded when they aggregate into functional amyloid polymers. The most common infectious disease in humans, tooth decay, involves the formation of microbial communities in biofilms on teeth.

Biological Small-angle X-ray Scattering (BioSAXS), Fiber diffraction
BL4-2
May 2020
Akif Tezcan, University of California, San Diego
Figure 2

Some proteins can form complex cage structures that can trap, hold, catalyze, and release small molecular and atomic cargo based on environmental signals. These protein cages are made of a collection of identical monomer proteins self-assembled into a symmetric conformation. Protein cages are found in nature, including in virus capsids, and have attracted much interest for engineering them to perform specific functions. In the past, designed protein cages have formed highly porous, “wiffle-ball”-like assemblies, but a team of scientists have used knowledge of inorganic chemistry, such as metal-coordination preferences, to design a tightly-packed protein cage that more closely mimics natural protein cages.

Macromolecular Crystallography
BL9-2, BL12-2
May 2020
Johanna Nelson Weker, Stanford Synchrotron Radiation Lightsource
Figure

Because they are highly efficient, low maintenance, and light, lithium-ion batteries have grown in popularity. Their use has improved the functionality of many electronics, such as allowing our cell phones to be more portable and our electric cars to travel longer distances. However, some precious metal components of these batteries are in short supply, prompting researchers to develop “beyond lithium-ion” alternatives that use elements more abundant on Earth, yet have the qualities that make lithium-ion batteries so useful. Attention has turned to using common divalent metals, such as calcium, magnesium, and zinc, at the anode for a new type of battery.

X-ray diffraction
BL2-1, BL11-3
May 2020
Johanna Nelson Weker, Stanford Synchrotron Radiation Lightsource
Figure 1

While steady improvement of lithium-ion batteries has allowed electronic technologies to perform better, researchers are nearing a theoretical limit to lithium-ion battery capacity. One way to overcome this limit is to change the chemistry of materials to allow more electrons to exchange between anode and cathode per unit of material. Currently, LiCoO2 lithium-ion batteries transfer one electron per unit of cathode, but other lithium-based materials may allow for higher capacity. A team of researchers has investigated the Li-rich layered sulfide Li2FeS2 and a novel analog LiNaFeS2 as potential higher capacity alternatives since they can store 1.5 or more electrons per unit.

X-ray Absorption Spectroscopy
BL4-1, BL4-3
February 2020
Ilya Belopolski, Princeton University, M. Zahid Hasan, Princeton University

Physicists have been interested in crystalline materials where the quantum mechanical behavior of electrons is governed by topology, so-called topological quantum matter. Recently the community has been particularly excited about crystals which additionally exhibit magnetism, i.e. topological quantum magnets. What new topological behavior might such magnets exhibit? Can we find examples of such exotic quantum magnets in nature? And could magnetic topological phases of matter lead to insights about fundamental questions in science or pave the way to technological applications?
 

Angle-resolved photoelectron spectroscopy
BL5-2
February 2020
Stephen G. Boxer, Stanford University

Organisms including microbes, plants, and animals can interpret light as a signal for action. While this is a fundamental and important process, the mechanism still holds mystery. How are photons converted into molecular signals? At the most basic step, a light-sensing molecule, a chromophore, undergoes a conformational change, an isomerization, when it encounters a photon. Many details are still unknown, which impacts efforts to engineer artificial light-sensing systems based on natural systems. A team of scientists has illuminated the importance of the immediate electrostatic environment of the chromophore on photoisomerization.

Macromolecular Crystallography
BL7-1, BL12-2, BL14-1
January 2020
Donghui Lu

In superconducting materials, electron clouds can align into a specific order termed nematicity, a word taken from a root meaning string-like and previously used for alignment of molecules in liquid crystal displays (LCDs). Most iron-based high temperature superconductors (FeSCs) exhibit nematic order and magnetic order in conjunction with superconducting behavior. Iron selenide (FeSe) is a type of FeSC material that obtains nematic but not magnetic alignment prior to reaching the superconducting state. This provides an excellent opportunity to disentangle the contribution of these two orders that usually emerge simultaneously. Studies of FeSe have faced the challenge that FeSe crystals break into orthogonally-oriented domains at the onset of nematic order, a process called twinning. A team of researchers has found a way to detwin FeSe crystals to examine the nematic state to gain a deeper understanding of how it affects superconductivity. 

Angle-resolved photoelectron spectroscopy
BL5-2
November 2019
Johanna Nelson Weker, SSRL

3D printing is revolutionizing the manufacture of products, promising fast and inexpensive ways to make quick prototypes, small batch parts, and unique pieces exactly to specifications. The uses for 3D printed metal range from specialized car parts to custom medical prosthetics. While the potential applications are many, there are limitations due to variable quality and strength of the products. To improve these materials, the science of the manufacturing processes needs to be better understood. Laser powder bed fusion (LPBF) additive manufacturing is a 3D printing process where a three dimensional part is built layer by layer.

BL2-2

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