Advanced Light Source (ALS) – Page 10

Modified antibody clarifies tumor-killing mechanisms

2018/01/262018/02/02

The structure of an antibody was modified to selectively activate a specific pathway of the immune system, demonstrating its value in killing tumor cells.

Immunotherapy—the use of the immune system to fight disease—has made tremendous progress in the fight against cancer. Antibodies such as immunoglobulin G (IgG) can identify and attack foreign or abnormal substances, including tumor cells. But to control and amplify this response, scientists need to know more about how elements of the immune system recognize tumor cells and trigger their destruction. There are two main pathways for this: antibody-dependent mechanisms and complement-dependent mechanisms.

The antibody pathway involves coating the surfaces of tumor cells with antibodies that recruit “natural killer” (NK) cells and macrophages (a type of white blood cell) to destroy the tumor cells. The complement pathway (so named because it complements the antibody pathway) also engages NK cells and macrophages and includes a third mechanism—a cascade of events culminating in tumor-cell destruction via a membrane attack complex (MAC).

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Image: extract of a schematic illustration (see on the ALS webpage)

X-ray experiments suggest high tunability of 2-D material

2018/01/262018/01/31

Scientists at Berkeley Lab use a new platform, called MAESTRO, to see microscale details in monolayer material’s electronic structure

To see what is driving the exotic behavior in some atomically thin – or 2-D – materials, and find out what happens when they are stacked like Lego bricks in different combinations with other ultrathin materials, scientists want to observe their properties at the smallest possible scales.

Enter MAESTRO, a next-generation platform for X-ray experiments at the Advanced Light Source (ALS) at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), that is providing new microscale views of this weird 2-D world.

In a study published Jan. 22 in the journal Nature Physics, researchers zeroed in on signatures of exotic behavior of electrons in a 2-D material with microscale resolution.

The new insights gleaned from these experiments show that the properties of the 2-D semiconductor material they studied, called tungsten disulfide (WS₂), may be highly tunable, with possible applications for electronics and other forms of information storage, processing, and transfer.

Those applications could include next-gen devices spawned from emerging fields of research like spintronics, excitonics and valleytronics. In these fields, researchers seek to manipulate properties like momentum and energy levels in a material’s electrons and counterpart particles to more efficiently carry and store information – analogous to the flipping of ones and zeroes in conventional computer memory.

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Picture: Extract of a rendering showing a “ball-and-stick” representation of the atomic structure of a 2-D single crystalline layer of tungsten disulfide (blue and yellow) on top of layers of 2-D boron nitride (silver and gold). On top of these is a representation of the structure of electronic energy levels, or valence bands, within the tungsten disulfide, and the increased splitting between the two valence bands observed using an x-ray technique at the MAESTRO beamline. The experiments suggest the effect could be due to “trions,” made up of two holes and an electron in the bands, depicted as clear and dark spheres. The background is raw data of the electronic structure of the tungsten disulfide, as measured in the experiment.
Credit: Chris Jozwiak/Berkeley Lab

Fuel from the sun: insight into electrode performance

2018/01/232018/02/02

Soft x-ray studies of hematite electrodes—potentially key components in producing fuel from sunlight—revealed the material’s electronic band positions under realistic operating conditions.

In photosynthesis, plants use sunlight to split water into oxygen and hydrogen. The oxygen is released into the atmosphere, and the hydrogen is used to produce molecules—such as carbohydrates and sugars—that store energy in chemical bonds. Such compounds constitute the original feedstocks for subsequent forms of fuel consumed by society.

Photoelectrochemical (PEC) water splitting is a form of “artificial” photosynthesis that uses semiconductor material, rather than organic plant material, to facilitate water splitting. Electrodes made of semiconductor material are immersed in an electrolyte, with sunlight driving the water-splitting process. The performance of such PEC devices is largely determined at the interface between the photoanode (the electrode at which light gets absorbed) and the electrolyte.

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Photo: Roy Kaltschmidt

Berkeley Lab delivers injector that will drive X-Ray laser upgrade

2018/01/22

Unique device will create bunches of electrons to stimulate million-per-second X-ray pulses

Every powerful X-ray pulse produced for experiments at a next-generation laser project, now under construction, will start with a “spark” – a burst of electrons emitted when a pulse of ultraviolet light strikes a 1-millimeter-wide spot on a specially coated surface.

A team at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) designed and built a unique version of a device, called an injector gun, that can produce a steady stream of these electron bunches that will ultimately be used to produce brilliant X-ray laser pulses at a rapid-fire rate of up to 1 million per second.

The injector arrived Jan. 22 at SLAC National Accelerator Laboratory (SLAC) in Menlo Park, California, the site of the Linac Coherent Light Source II (LCLS-II), an X-ray free-electron laser project.

Getting up to speed

The injector will be one of the first operating pieces of the new X-ray laser. Initial testing of the injector will begin shortly after its installation.

The injector will feed electron bunches into a superconducting particle accelerator that must be supercooled to extremely low temperatures to conduct electricity with nearly zero loss. The accelerated electron bunches will then be used to produce X-ray laser pulses.

Image: Joe Wallig, left, a mechanical engineering associate, and Brian Reynolds, a mechanical technician, work on the final assembly of the LCLS-II injector gun in a specially designed clean room at Berkeley Lab in August.
Credit: Marilyn Chung/Berkeley Lab

Scientists discover material ideal for smart photovoltaic windows

2018/01/222018/01/24

Berkeley Lab researchers make thermochromic windows with perovskite solar cell

Smart windows that are transparent when it’s dark or cool but automatically darken when the sun is too bright are increasingly popular energy-saving devices. But imagine that when the window is darkened, it simultaneously produces electricity. Such a material – a photovoltaic glass that is also reversibly thermochromic – is a green technology researchers have long worked toward, and now, scientists at Lawrence Berkeley National Laboratory (Berkeley Lab) have demonstrated a way to make it work.

Researchers at Berkeley Lab, a Department of Energy (DOE) national lab, discovered that a form of perovskite, one of the hottest materials in solar research currently due to its high conversion efficiency, works surprisingly well as a stable and photoactive semiconductor material that can be reversibly switched between a transparent state and a non-transparent state, without degrading its electronic properties.

Image Credit: iStock

A path to a game-changing battery electrode

2018/01/162018/01/24

If you add more lithium to the positive electrode of a lithium-ion battery, it can store much more charge in the same amount of space, theoretically powering an electric car 30 to 50 percent farther between charges. But these lithium-rich cathodes quickly lose voltage, and years of research have not been able to pin down why—until now.

Image: Electric car makers are intensely interested in lithium-rich battery cathodes made of layers of lithium sandwiched between layers of transition-metal oxides. Such cathodes could significantly increase driving range.
Credit: Stanford University/3Dgraphic

X-Rays Reveal ‘Handedness’ in Swirling Electric Vortices

2018/01/152018/01/17

Scientists at Berkeley Lab study exotic material’s properties, which could make possible a new form of data storage

Scientists used spiraling X-rays at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) to observe, for the first time, a property that gives handedness to swirling electric patterns – dubbed polar vortices – in a synthetically layered material.

Ingredients for Life Revealed in Meteorites That Fell to Earth

2018/01/102018/01/17

Study, based in part at Berkeley Lab, also suggests dwarf planet in asteroid belt may be a source of rich organic matter

Two wayward space rocks, which separately crashed to Earth in 1998 after circulating in our solar system’s asteroid belt for billions of years, share something else in common: the ingredients for life. They are the first meteorites found to contain both liquid water and a mix of complex organic compounds such as hydrocarbons and amino acids.

Studying Gas Mask Filters So People Can Breathe Easier

2017/12/072018/01/17

Scientists have put the x-ray spotlight on composite materials in respirators used by the military, police, and first responders. The results provide reassuring news about the effectiveness of current filters and provide fundamental information that could lead to more advanced gas masks as well as protective gear for civilian applications.

Ferromagnetism Emerges to Alleviate Polar Mismatch

2017/12/042018/01/17

Alchemists dreamed of turning boring, base metals into exotic, noble metals. Although such dreams were never realized, scientists today can induce unexpected properties at the interface between two materials—including properties not present in either parent material. For example, researchers have discovered that if they combine SrTiO3 (a dielectric and paramagnetic material) together with LaMnO3 (an insulating and antiferromagnetic material) in just the right way, they can induce an insulating ferromagnetic state at the interface.

Watching a Quantum Material Lose Its Stripes

2017/11/292017/12/07

Berkeley Lab study uses terahertz laser pulses to reveal ultrafast coupling of atomic-scale patterns

Stripes can be found everywhere, from zebras roaming in the wild to the latest fashion statement. In the world of microscopic physics, periodic stripe patterns can be formed by electrons within so-called quantum materials.

Scientists at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) have now disentangled the intriguing dynamics of how such atomic-scale stripes melt and form, providing fundamental insights that could be useful in the development of novel energy materials.

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Image: Illustration of an ultrashort laser light striking a lanthanum strontium nickel oxide crystal, triggering the melting of atomic-scale stripes. The charges (yellow) quickly become mobile while the crystal distortions react only with delay, exposing the underlying interactions.
Credit: Robert Kaindl/Berkeley Lab

New Catalyst Gives Artificial Photosynthesis a Big Boost

2017/11/292017/12/07

Inspired by plants: Inorganic catalyst converts electrical energy to chemical energy at 64% efficiency

Researchers have created a new catalyst that brings them one step closer to artificial photosynthesis — a system that would use renewable energy to convert carbon dioxide (CO₂) into stored chemical energy.

As in plants, their system consists of two linked chemical reactions: one that splits water (H₂O) into protons and oxygen gas, and another that converts CO₂ into carbon monoxide (CO). The CO can then be converted into hydrocarbon fuels through an established industrial process. The system would allow both the capture of carbon emissions and the storage of energy from solar or wind power.

Yufeng Liang and David Prendergast – scientists at the Molecular Foundry, a nanoscale research facility at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) – performed theoretical modeling work used to interpret X-ray spectroscopy measurements made in the study, published Nov. 20 in Nature Chemistry. This work was done in support of a project originally proposed by the University of Toronto team to the Molecular Foundry, a DOE Office of Science User Facility.

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Image: Phil De Luna of University of Toronto is one of the lead authors of a new study that reports a low-cost, highly efficient catalyst for chemical conversion of water into oxygen. The catalyst is part of an artificial photosynthesis system in development at the University of Toronto.
Credit: Tyler Irving/University of Toronto

X-Rays reveal the biting truth about parrotfish teeth

2017/11/152017/11/29

Interwoven crystal structure is key to coral-crunching ability

So, you thought the fictional people-eating great white shark in the film “Jaws” had a powerful bite. But don’t overlook the mighty mouth of the parrotfish – its hardy teeth allow it to chomp on coral all day long, ultimately chewing and grinding it up through digestion into fine sand. That’s right: Its “beak” creates beaches. A single parrotfish can produce hundreds of pounds of sand each year.

Now, a study by scientists – including those at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) – has revealed a chain mail-like woven microstructure that gives parrotfish teeth their remarkable bite and resilience.

The natural structure they observed also provides a blueprint for creating ultra-durable synthetic materials that could be useful for mechanical components in electronics, and in other devices that undergo repetitive movement, abrasion, and contact stress.

Matthew Marcus, a staff scientist working at Berkeley Lab’s Advanced Light Source (ALS) – an X-ray source known as a synchrotron light source that was integral in the parrotfish study – became intrigued with parrotfish during a 2012 visit to the Great Barrier Reef off of the coast of Australia.

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Image: Scientists studied the microstructure of the coral-chomping teeth of the steephead parrotfish, pictured here, to learn about the fish’s powerful bite.
Credit: Alex The Reef Fish Geek/Nautilus Scuba Club, Cairns, Australia

Natalie Larson awarded

2017/11/142017/12/07

She received the Neville B. Smith Student Poster Prize

Natalie Larson, a current ALS doctoral fellow from UC Santa Barbara, won the first prize Neville B. Smith Student Poster Award at the 2017 ALS User Meeting. Larson’s winning poster—”In-situ x-ray computed tomography of defect evolution during polymer impregnation and pyrolysis processing of ceramic matrix composites”—featured the first two big in situ experiments she performed at Beamline 8.3.2.

Larson has been an ALS user since 2014 and became a doctoral fellow in 2016. She’ll continue at the ALS for about another year through a National Science Foundation fellowship that will see her through the end of her PhD. The primary focus of her work is developing high-temperature ceramic matrix composites (CMCs) for more efficient jet engines. Larson works with Beamline Scientists Dula Parkinson and Alastair MacDowell and Project Scientist Harold Barnard on developing experiments for in situ x-ray computed tomography experiments to observe 3D real-time defect formation in CMCs.

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Fuel cell X-Ray study details effects of temperature and moisture on performance

2017/11/132017/11/29

Experiments at Berkeley Lab’s Advanced Light Source help scientists shed light on fuel-cell physics

Like a well-tended greenhouse garden, a specialized type of hydrogen fuel cell – which shows promise as a clean, renewable next-generation power source for vehicles and other uses – requires precise temperature and moisture controls to be at its best. If the internal conditions are too dry or too wet, the fuel cell won’t function well.

But seeing inside a working fuel cell at the tiny scales relevant to a fuel cell’s chemistry and physics is challenging, so scientists used X-ray-based imaging techniques at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and Argonne National Laboratory to study the inner workings of fuel-cell components subjected to a range of temperature and moisture conditions.

The research team, led by Iryna Zenyuk, a former Berkeley Lab postdoctoral researcher now at Tufts University, included scientists from Berkeley Lab’s Energy Storage and Distributed Resources Division and the Advanced Light Source (ALS), an X-ray source known as a synchrotron.

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Image: This animated 3-D rendering (view larger size), generated by an X-ray-based imaging technique at Berkeley Lab’s Advanced Light Source, shows tiny pockets of water (blue) in a fibrous sample. The X-ray experiments showed how moisture and temperature can affect hydrogen fuel-cell performance.
Credit: Berkeley Lab

A Bacterial Jigsaw Puzzle Is Solved

2017/08/112017/10/16

Scientists worked on bacterial microcompartments and discovered how the pieces fit together.

Bacterial microcompartments (BMCs) are hollow protein shells that encapsulate enzymes involved in bacterial metabolism. They serve to co-localize the enzymes and their reactants for greater efficiency, as well as to sequester reaction products from the rest of the cell. Despite the availability of structural information on individual shell components, the principles governing how the pieces fit together have remained elusive.

Researchers have now performed protein crystallography studies at the ALS and at Stanford Synchrotron Radiation Lightsource (SSRL) of a fully assembled BMC as well as its separate building blocks. The resulting atomic-resolution views reveal the basic principles of shell construction and provide important information for fighting pathogens and for bioenergy or biotechnology applications.

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