From PNNL Lab: “Striking While the Iron Is Hot”

Chromatography combined with database search strategy identifies hard-to-find heme proteins

March 2013
Suraiya Farukhi
Christine Sharp

“Results: Heme c is an important iron-containing post-translational modification found in many proteins. It plays an important role in respiration, metal reduction, and nitrogen fixation, especially anaerobic respiration of environmental microbes. Such bacteria and their c-type cytochromes are studied extensively because of their potential use in bioremediation, microbial fuel cells, and electrosynthesis of valuable biomaterials.

Heme C

Until recently, these modifications were hard to find using traditional proteomic methods. Scientists at Pacific Northwest National Laboratory combined a heme c tag protein affinity purification strategy called histidine affinity chromatography (HAC) with enhanced database searching. This combination confidently identified heme c peptides in liquid chromatography-tandem mass spectrometry (LC-MS/MS) experiments-by as much as 100-fold in some cases.”

Why It Matters: Iron is a critical part of many biological processes; however, it is often not biologically available or it can be toxic in high quantities. So, biological systems have developed intricate methods to use and store iron. Many environmentally important microbes and microbial communities are rich in c-type cytochromes. Combining HAC and data analysis tailored to the unique properties of heme c peptides should enable more detailed study of the role of c-type cytochromes in these microbes and microbial communities.

‘Several proteomics studies have analyzed the expression of c-type cytochromes under various conditions,’ said PNNL postdoctoral researcher Dr. Eric Merkley, and lead author of a paper that appeared in the Journal of Proteome Research. ‘A shared feature of these studies is that the cytochrome-rich fractions, the cell envelope or extracellular polymeric substance, were purified and explicitly analyzed to efficiently detect cytochromes. Analyses of large-scale proteomics datasets have typically suggested that c-type cytochromes, particularly the heme c peptides, are under-represented.’”

See the full article here.

Pacific Northwest National Laboratory (PNNL) is one of the United States Department of Energy National Laboratories, managed by the Department of Energy’s Office of Science. The main campus of the laboratory is in Richland, Washington.

PNNL scientists conduct basic and applied research and development to strengthen U.S. scientific foundations for fundamental research and innovation; prevent and counter acts of terrorism through applied research in information analysis, cyber security, and the nonproliferation of weapons of mass destruction; increase the U.S. energy capacity and reduce dependence on imported oil; and reduce the effects of human activity on the environment. PNNL has been operated by Battelle Memorial Institute since 1965.

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From M.I.T.: “New solar-cell design based on dots and wires”

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MIT researchers improve efficiency of quantum-dot photovoltaic system by adding a forest of nanowires.

March 25, 2013
David L. Chandler

“Using exotic particles called quantum dots as the basis for a photovoltaic cell is not a new idea, but attempts to make such devices have not yet achieved sufficiently high efficiency in converting sunlight to power. A new wrinkle added by a team of researchers at MIT — embedding the quantum dots within a forest of nanowires — promises to provide a significant boost.”

Scanning Electron Microscope images show an array of zinc-oxide nanowires (top) and a cross-section of a photovoltaic cell made from the nano wires, interspersed with quantum dots made of lead sulfide (dark areas). A layer of gold at the top (light band) and a layer of indium-tin-oxide at the bottom (lighter area) form the two electrodes of the solar cell.
Images courtesy of Jean, et al/Advanced Materials

See the full article here.

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From Berkeley Lab: “Berkeley Lab Researchers Use Metamaterials to Observe Giant Photonic Spin Hall Effect”

Berkeley Lab

March 21, 2013
Lynn Yarris

“Researchers with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) have once again demonstrated the incredible capabilities of metamaterials – artificial nanoconstructs whose optical properties arise from their physical structure rather than their chemical composition. Engineering a unique two-dimensional sheet of gold nanoantennas, the researchers were able to obtain the strongest signal yet of the photonic spin Hall effect, an optical phenomenon of quantum mechanics that could play a prominent role in the future of computing.

Light propagating through a metamaterial follows a curved trajectory that drags light with different circular polarization in opposite transverse directions to produce a giant photonic Spin Hall effect.

‘With metamaterial, we were able to greatly enhance a naturally weak effect to the point where it was directly observable with simple detection techniques,’ said Xiang Zhang, a faculty scientist with Berkeley Lab’s Materials Sciences Division who led this research. ‘We also demonstrated that metamaterials not only allow us to control the propagation of light but also allows control of circular polarization. This could have profound consequences for information encoding and processing.’

Zhang is the corresponding author of a paper describing this work in the journal Science. The paper is titled Photonic Spin Hall Effect at Metasurfaces. Co-authors are Xiaobo Yin, Ziliang Ye, Jun Sun Rho and Yuan Wang.

Metamaterials have garnered a lot of attention in recent years because their unique structure affords electromagnetic properties unattainable in nature. For example, a metamaterial can have a negative index of refraction, the ability to bend light backwards, unlike all materials found in nature, which bend light forward. Zhang, who holds the Ernest S. Kuh Endowed Chair Professor of Mechanical Engineering at the University of California (UC) Berkeley, where he also directs the National Science Foundation’s Nano-scale Science and Engineering Center, has been at the forefront of metamaterials research.

See the full article here.

A U.S. Department of Energy National Laboratory Operated by the University of California

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From Argonne: “Teasing Out the Nature of Structural Instabilities in Ceramic Compounds”

News from Argonne National Laboratory

MARCH 12, 2013
No Writer Credit

“Materials scientists have been for some time preparing artificial ceramic systems that simply do not exist in nature, allowing scientists to engineer particularly interesting and even technologically applicable behaviors. But sometimes nature itself finds ingenious solutions to physical problems that we have not been able to solve.

The simple perovskite structure of EuTiO3 illustrated above shows the essential competing structural instabilities. At the center of the figure is the oxygen cage rotation, and to the right is the central titanium displacement. X-ray diffraction studies showed that, to accommodate the incompatibility of these distortions, they naturally form a long, inter-digitized superstructure (illustrated at far left), which allows them to coexist. Ultimately, this research demonstrates that when both electric and magnetic fields are applied as the europium spins align, the oxygen cage responds, mediating communication between the titanium electric and europium magnetic parameters.

An international team of researchers lead by Argonne National Laboratory utilized high-brightness x-rays from the U.S. Department of Energy Office of Science’s Advanced Photon Source at Argonne National Laboratory, as well as the European Synchrotron Radiation Facility (ESRF), to study the rare-earth magnetic material europium titanate (EuTiO3). Their results were published in the journal Physical Review Letters.

In a magnetic field, the (near) optical properties of EuTiO3 change quite dramatically, presenting hope of a strong magneto-electric material often dreamed of by engineers for use in combining magnetic and charge parameters for many memory, processing, and sensor devices.

Emerging ceramic materials are displaying a tantalizing array of characteristics that could find application in existing and new technologies including magnetic, piezoelectric, ferroelectric, metal insulator transitions, and even superconductivity. Most interesting to physicists is the delicate nature balancing the underlying parameters that drive each quality. If one introduces a different mix of materials, perhaps replacing one element with another or even slightly distorting the structure, then one parameter disappears while another emerges. How all the separate electronic orbits behave and interact with respect to, and with, each other is a fascinating arena for scientists seeking to understand ceramics, a well-known and ancient material family.”

See the full article here.

Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy’s Office of Science

The Advanced Photon Source at Argonne National Laboratory is one of five national synchrotron radiation light sources supported by the U.S. Department of Energy’s Office of Science to carry out applied and basic research to understand, predict, and ultimately control matter and energy at the electronic, atomic, and molecular levels, provide the foundations for new energy technologies, and support DOE missions in energy, environment, and national security.

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From Berkeley Lab: “Surprising Control over Photoelectrons from a Topological Insulator”

Berkeley Lab

Berkeley Lab scientists discover how a photon beam can flip the spin polarization of electrons emitted from an exciting new material

“Plain-looking but inherently strange crystalline materials called 3D topological insulators (TIs) are all the rage in materials science. Even at room temperature, a single chunk of TI is a good insulator in the bulk, yet behaves like a metal on its surface.

The interior bulk of a topological insulator is indeed an insulator, but electrons (spheres) move swiftly on the surface as if through a metal. They are spin-polarized, however, with their momenta (directional ribbons) and spins (arrows) locked together. Berkeley Lab researchers have discovered that the spin polarization of photoelectrons (arrowed sphere at upper right) emitted when the material is struck with high-energy photons (blue-green waves from left) is completely determined by the polarization of this incident light. (Image Chris Jozwiak, Zina Deretsky, and Berkeley Lab Creative Services Office)

Researchers find TIs exciting partly because the electrons that flow swiftly across their surfaces are ‘spin polarized’: the electron’s spin is locked to its momentum, perpendicular to the direction of travel. These interesting electronic states promise many uses – some exotic, like observing never-before-seen fundamental particles, but many practical, including building more versatile and efficient high-tech gadgets, or, further into the future, platforms for quantum computing.

A team of researchers from the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California at Berkeley has just widened the vista of possibilities with an unexpected discovery about TIs: when hit with a laser beam, the spin polarization of the electrons they emit (in a process called photoemission) can be completely controlled in three dimensions, simply by tuning the polarization of the incident light.

‘The first time I saw this it was a shock; it was such a large effect and was counter to what most researchers had assumed about photoemission from topological insulators, or any other material,’ says Chris Jozwiak of Berkeley Lab’s Advanced Light Source (ALS), who worked on the experiment. ‘Being able to control the interaction of polarized light and photoelectron spin opens a playground of possibilities.’”

See the full article here.

A U.S. Department of Energy National Laboratory Operated by the University of California

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From INL: “Reverse mining: Scientists extract rare earth materials from consumer products”

Idaho National Laboratory

March 7, 2013
Nicole Stricker

“In a new twist on the state’s mining history, a group of Idaho scientists will soon be crushing consumer electronics rather than rocks in a quest to recover precious materials.

So-called rare earth elements are deeply embedded in everything from fluorescent light bulbs to smartphones — and they’re critical for electric vehicles, wind turbines and solar panels. Because these materials are subject to supply disruptions, the U.S. Department of Energy is investing in solutions to potential domestic shortages.

INL scientists will use expertise from recycling nuclear fuel to support the Critical Materials Innovation Hub. The national effort led by DOE’s Ames Laboratory is working to secure the supply of rare earth metals and other energy-critical materials.

Idaho National Laboratory scientists will contribute to that effort with expertise from recycling fissionable material from used nuclear fuel rods. They’ll now apply similar principles to separate rare earth metals and other critical materials from crushed consumer products. The work could also help improve extraction from the mining process.

‘We think of electronics as being a different kind of ore,’ says Eric Peterson, the business line lead for INL’s Process Science & Technology division. ‘Today’s consumer recycling efforts recover about 40 to 50 percent of the critical materials. Our goal is to get that to more like 80 percent recovery.’”

Scott Herbst helps lead the INL scientists studying ways to recycle rare earth and other critical elements from discarded electronics.

This is very important work. Other countries have the richest deposits of unmined rare earths. Some of these countries routinely manipulate the world supply. INL is hoping to help shield the U.S. from such tomfoolery. Always be sure to properly recycle discarded items such as those noted at the beginning of the article. See the full article here.

In operation since 1949, INL is a science-based, applied engineering national laboratory dedicated to supporting the U.S. Department of Energy’s missions in nuclear and energy research, science, and national defense. INL is operated for the Department of Energy (DOE) by Battelle Energy Alliance (BEA) and partners, each providing unique educational, management, research and scientific assets into a world-class national laboratory.

From Berkeley Lab: “Long Predicted Atomic Collapse State Observed in Graphene”

Berkeley Lab

Berkeley Lab researchers recreate elusive phenomenon with artificial nuclei

March 07, 2013
Lynn Yarris

“The first experimental observation of a quantum mechanical phenomenon that was predicted nearly 70 years ago holds important implications for the future of graphene-based electronic devices. Working with microscopic artificial atomic nuclei fabricated on graphene, a collaboration of researchers led by scientists with the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) Berkeley have imaged the “atomic collapse” states theorized to occur around super-large atomic nuclei.

An artificial atomic nucleus made up of five charged calcium dimers is centered in an atomic-collapse electron cloud. (Image courtesy of Michael Crommie)

‘Atomic collapse is one of the holy grails of graphene research, as well as a holy grail of atomic and nuclear physics,’ says Michael Crommie, a physicist who holds joint appointments with Berkeley Lab’s Materials Sciences Division and UC Berkeley’s Physics Department. ‘While this work represents a very nice confirmation of basic relativistic quantum mechanics predictions made many decades ago, it is also highly relevant for future nanoscale devices where electrical charge is concentrated into very small areas.’”

Michael Crommie is a physicist who holds joint appointments with Berkeley Lab’s Materials Sciences Division and UC Berkeley’s Physics Department. (Photo by Roy Kaltschmidt)

See the full article here.

A U.S. Department of Energy National Laboratory Operated by the University of California

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From Berkeley Lab: “In the Blink of an Eye: X-ray Imaging on the Attosecond Timescale”

Berkeley Lab

March 07, 2013
Lynn Yarris

“In the blink of an eye, more attoseconds have expired than the age of Earth measured in – minutes. A lot more. To be precise, an attosecond is one billionth of a billionth of a second. The attosecond timescale is where you must go to study the electron action that is the starting point of all of chemistry. Not surprisingly, chemists are most eager to explore it with X-rays, the region of the electromagnetic spectrum that can probe the core electrons of atoms, the electrons that uniquely identify atomic species.

Berkeley Lab’s Ali Belkacem

Ali Belkacem, a chemist with the Lawrence Berkeley National Laboratory, has been using powerful laboratory-scale lasers to test whether multidimensional nonlinear x-ray spectroscopy on the attosecond timescale is practical for the light sources of the future – and just what combination of beam characteristics is needed to define them.

Heralded as the science of the 21st century by Science and The Economist, attosecond science is a new frontier of molecular and material science. It is expected to catalyze novel applications in a wide range of fields such as nanotechnology and life sciences, based on the ultimate visualization and control of the quantum nature of the electron.”

See the full article here.

A U.S. Department of Energy National Laboratory Operated by the University of California

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From Berkeley Lab: “Engineering Bacterial Live Wires”

Berkeley Lab

February 28, 2013
Lita Stephenson

Just like electronics, living cells use electrons for energy and information transfer. Despite electrons being a common ‘language’ of the living and electronic worlds, living cells cannot speak to our largely technological realm. Cell membranes are largely to blame for this inability to plug cells into our computers: they form a greasy barrier that tightly controls charge balance in a cell. Thus, giving a cell the ability to communicate directly with an electrode would lead to enormous opportunities in the development of new energy conversion techniques, fuel production, biological reporters, or new forms of bioelectronic systems.

Previous studies performed by scientists and collaborators at Lawrence Berkeley National Laboratory’s (Berkeley Lab) Molecular Foundry have made enormous headway toward cellular-electrode communication by using E. coli as a testbed for expressing an electron transfer pathway naturally occurring in a bacterial species called Shewanella oneidensis MR-1. The engineered E. coli was able to use the protein complex to reduce nanocrystalline iron oxide (Jensen, et al. (2010) PNAS.). Building off of this research, a group led by Caroline Ajo-Franklin, a staff scientist in the Biological Nanostructures Facility at Berkeley Lab’s Molecular Foundry studying synthetic biology, has now demonstrated that these engineered E. coli strains can generate measurable current at an anode.

The results of this new study, Tuning promoter strengths for improved synthesis and function of electron conduits in Escherichia coli, have recently been published in ACS Synthetic Biology, the American Chemical Society’s new flagship journal for synthetic biology.

Authors of the recent publication in the Biological Nanostructures Laboratory. From left to right: Caroline Ajo-Franklin, Heather Jensen, Matt Hepler, Cheryl Goldbeck

See the full article here.

A U.S. Department of Energy National Laboratory Operated by the University of California

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From Berkeley Lab: “New Opportunities for Crystal Growth”

Berkeley Lab

Berkeley Lab Facility Provides Unique Capabilities for the Synthesis of New Crystals and Materials

February 25, 2013
Lynn Yarris

“Talk with material scientist Edith Bourret-Courchesne about what it takes to grow and develop useful crystals and a word you will hear repeated often is “patience.” As the leader of a unique crystal growth facility at Lawrence Berkeley National Laboratory (Berkeley Lab) dedicated to the synthesis of crystals and new materials, patience is more than a virtue, it’s a necessity.

Edith Bourret-Courchesne, Berkeley Lab materials scientist, heads a facility that provides a wide range of crystal purification, growth and characterization capabilities. (Photo by Roy Kaltschmidt)

‘The growth of every crystal is unique, like the formation of a snowflake, and since we work with compounds that have never before been crystallized the processes by which we grow our crystals are also unique,’ she says. ‘As a result, a lot of our research is aimed at understanding why something didn’t work.’

Bourret-Courchesne is a senior scientist with Berkeley Lab’s Materials Sciences Division where she has been studying the synthesis of new crystals and materials since 1984…In 2008, Bourret-Courchesne’s crystal growth research effort received a much welcomed boost in the form of a grant from the U.S. Department of Energy (DOE) through the National Nuclear Security Agency (NNSA). This NNSA grant enabled Berkeley Lab to acquire the capabilities needed to grow and develop new single crystals as high-performance scintillators that can be used for the detection of nuclear materials.”

See the full very informative article here.

A U.S. Department of Energy National Laboratory Operated by the University of California

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