Tagged: Brookhaven National Labs Toggle Comment Threads | Keyboard Shortcuts

  • richardmitnick 3:10 pm on September 15, 2014 Permalink | Reply
    Tags: Brookhaven National Labs, ,   

    From BNL: “Elusive Quantum Transformations Found Near Absolute Zero” 

    Brookhaven Lab

    September 15, 2014
    Justin Eure, (631) 344-2347 or Peter Genzer, (631) 344-3174

    Brookhaven Lab and Stony Brook University researchers measure the quantum fluctuations behind a novel magnetic material’s ultra-cold ferromagnetic phase transition.

    Heat drives classical phase transitions—think solid, liquid, and gas—but much stranger things can happen when the temperature drops. If phase transitions occur at the coldest temperatures imaginable, where quantum mechanics reigns, subtle fluctuations can dramatically transform a material.

    Scientists from the U.S. Department of Energy’s Brookhaven National Laboratory and Stony Brook University have explored this frigid landscape of absolute zero to isolate and probe these quantum phase transitions with unprecedented precision.

    two
    Liusuo Wu, a Stony Brook University Ph.D. student and lead author on the study, with his postdoctoral advisor (and study coauthor) Meigan Aronson, a Brookhaven Lab physicist and Stony Brook professor

    “Under these cold conditions, the electronic, magnetic, and thermodynamic performance of metallic materials is defined by these elusive quantum fluctuations,” said study coauthor Meigan Aronson, a physicist at Brookhaven Lab and professor at Stony Brook. “For the first time, we have a picture of one of the most fundamental electron states without ambient heat obscuring or complicating those properties.”

    The scientists explored the onset of ferromagnetism—the same magnetic polarization exploited in advanced electronic devices, electrical motors, and even refrigerator magnets—in a custom-synthesized iron compound as it approached absolute zero.

    The research provides new methods to identify and understand novel materials with powerful and unexpected properties, including superconductivity—the ability to conduct electricity with perfect efficiency. The study will be published online Sept. 15, 2014, in the journal Proceedings of the National Academy of Sciences.

    “Exposing this quantum phase transition allows us to predict and potentially boost the performance of new materials in practical ways that were previously only theoretical,” said study coauthor and Brookhaven Lab physicist Alexei Tsvelik.

    Mapping Quantum Landscapes

    cry
    Rendering of the near–perfect crystal structure of the yttrium–iron–aluminum compound used in the study. The two–dimensional layers of the material allowed the scientists to isolate the magnetic ordering that emerged near absolute zero.

    The presence of heat complicates or overpowers the so-called quantum critical fluctuations, so the scientists conducted experiments at the lowest possible temperatures.

    “The laws of thermodynamics make absolute zero unreachable, but the quantum phase transitions can actually be observed at nonzero temperatures,” Aronson said. “Even so, in order to deduce the full quantum mechanical nature, we needed to reach temperatures as low as 0.06 Kelvin—much, much colder than liquid helium or even interstellar space.”

    The researchers used a novel compound of yttrium, iron, and aluminum (YFe2Al10), which they discovered while searching for new superconductors. This layered, metallic material sits poised on the threshold of ferromagnetic order, a key and very rare property.

    “Our thermodynamic and magnetic measurements proved that YFe2Al10 becomes ferromagnetic exactly at absolute zero—a sharp contrast to iron, which is ferromagnetic well above room temperature,” Aronson said. “Further, we used magnetic fields to reverse this ferromagnetic order, proving that quantum fluctuations were responsible.”

    The collaboration produced near-perfect samples to prove that material defects could not impact the results. They were also the first group to prepare YFe2Al10 in single-crystal form, which allowed them to show that the emergent magnetism resided within two-dimensional layers.

    “As the ferromagnetism decayed with heat or applied magnetic fields, we used theory to identify the spatial and temporal fluctuations that drove the transition,” Tsvelik said. “That fundamental information provides insight into countless other materials.”

    Quantum Clues to New Materials

    The scientists plan to modify the composition of YFe2Al10 so that it becomes ferromagnetic at nonzero temperatures, opening another window onto the relationship between temperature, quantum transitions, and material performance.

    “Robust magnetic ordering generally blocks superconductivity, but suppressing this state might achieve the exact balance of quantum fluctuations needed to realize unconventional superconductivity,” Tsvelik said. “It is a matter of great experimental and theoretical interest to isolate these competing quantum interactions that favor magnetism in one case and superconductivity on the other.”

    Added Aronson, “Having more examples displaying this zero-temperature interplay of superconductivity and magnetism is crucial as we develop a holistic understanding of how these phenomena are related and how we might ultimately control these properties in new generations of materials.”

    Other authors on this study include Liusuo Wu, Moosung Kim, and Keeseong Park, all of Stony Brook University’s Department of Physics and Astronomy.

    The research was conducted at Brookhaven Lab’s Condensed Matter Physics and Materials Science Department and supported by the U.S. Department of Energy’s Office of Science (BES).

    BNL Campus

    See the full article here.

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world.Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
    i1

    ScienceSprings relies on technology from

    MAINGEAR computers

    Lenovo
    Lenovo

    Dell
    Dell

     
  • richardmitnick 9:38 am on August 29, 2014 Permalink | Reply
    Tags: , Brookhaven National Labs, ,   

    From BNL Lab: “DOE ‘Knowledgebase’ Links Biologists, Computer Scientists to Solve Energy, Environmental Issues” 

    Brookhaven Lab

    August 29, 2014
    Rebecca Harrington

    With new tool, biologists don’t have to be programmers to answer big computational questions

    If biologists wanted to determine the likely way a particular gene variant might increase a plant’s yield for producing biofuels, they used to have to track down several databases and cross-reference them using complex computer code. The process would take months, especially if they weren’t familiar with the computer programming necessary to analyze the data.

    ikb
    Combining information about plants, microbes, and the complex biomolecular interactions that take place inside these organisms into a single, integrated “knowledgebase” will greatly enhance scientists’ ability to access and share data, and use it to improve the production of biofuels and other useful products.

    Now they can do the same analysis in a matter of hours, using the Department of Energy’s Systems Biology Knowledgebase (KBase), a new computational platform to help the biological community analyze, store, and share data. Led by scientists at DOE’s Lawrence Berkeley, Argonne, Brookhaven, and Oak Ridge national laboratories, KBase amasses the data available on plants, microbes, microbial communities, and the interactions among them with the aim of improving the environment and energy production. The computational tools, resources, and community networking available will allow researchers to propose and test new hypotheses, predict biological behavior, design new useful functions for organisms, and perform experiments never before possible.

    “Quantitative approaches to biology were significantly developed during the last decade, and for the first time, we are now in a position to construct predictive models of biological organisms,” said computational biologist Sergei Maslov, who is principal investigator (PI) for Brookhaven’s role in the effort and Associate Chief Science Officer for the overall project, which also has partners at a number of leading universities, Cold Spring Harbor Laboratory, the Joint Genome Institute, the Environmental Molecular Sciences Laboratory, and the DOE Bioenergy Centers. “KBase allows research groups to share and analyze data generated by their project, put it into context with data generated by other groups, and ultimately come to a much better quantitative understanding of their results. Biomolecular networks, which are the focus of my own scientific research, play a central role in this generation and propagation of biological knowledge.”

    Maslov said the team is transitioning from the scientific pilot phase into the production phase and will gradually expand from the limited functionality available now. By signing up for an account, scientists can access the data and tools free of charge, opening the doors to faster research and deeper collaboration.
    Easy coding

    “We implement all the standard tools to operate on this kind of key data so a single PI doesn’t need to go through the hassle by themselves.”
    — Shinjae Yoo, assistant computational scientist working on the project at Brookhaven

    As problems in energy, biology, and the environment get bigger, the data needed to solve them becomes more complex, driving researchers to use more powerful tools to parse through and analyze this big data. Biologists across the country and around the world generate massive amounts of data — on different genes, their natural and synthetic variations, proteins they encode, and their interactions within molecular networks — yet these results often don’t leave the lab where they originated.

    “By doing small-scale experiments, scientists cannot get the system-level understanding of biological organisms relevant to the DOE mission,” said Shinjae Yoo, an assistant computational scientist working on the project at Brookhaven. “But they can use KBase for the analysis of their large-scale data. KBase will also allow them to compare and contrast their data with other key datasets generated by projects funded by the DOE and other agencies. We implement all the standard tools to operate on this kind of key data so a single PI doesn’t need to go through the hassle by themselves.”

    For non-programmers, KBase offers a “Narrative Interface,” allowing them to upload their data to KBase and construct a narrative of their analysis with a series of pre-coded programs that has a human in the middle interpreting and filtering their output.

    In one pre-coded narrative, researchers can filter through naturally occurring variations of Poplar genes, one of the DOE flagship bioenergy plant species. Scientists can discover genes associated with a reduced amount of lignin—a cell wall protein that makes conversion of Poplar biomass to biofuels more difficult. In this narrative, scientists can use datasets from KBase and from their own research to then find candidate genes, and use networks to select the genes most likely to be related to a specific trait they’re looking for—say, genes that result in reduced lignin content, which could ease the biomass to biofuel conversion. And if other researchers wanted to run the same program for a different plant, they could just put different data in the same narrative.

    “Everything is already there,” Yoo said. “You simply need to upload the data in the right format and run through several easy steps within the narrative.”

    For those who know how to code, KBase has the IRIS Interface, a web-based command line terminal where researchers can run and control the programs on their own, allowing scientists to analyze large volumes of data. If researchers want to learn how to do the coding themselves, KBase also has tutorials and resources to help interested scientists learn it.
    A social network

    But KBase’s most powerful resource is the community itself. Researchers are encouraged to upload their data and programs so that other users can benefit from them. This type of cooperative environment encourages sharing and feedback among researchers, so the programs, tools, and annotation of datasets can improve with other users’ input.

    Brookhaven is leading the plant team on the project, while the microbe and microbial community teams are based at other partner institutions. A computer scientist by training, Yoo said his favorite part of working on KBase has been how much biology he’s learned. Acting as a go-between among the biologists at Brookhaven, who are describing what they’d like to see KBase be able to do, and the computer scientists, who are coding the programs to make it happen, Yoo has had to understand both languages of science.

    “I’m learning plant biology. That’s pretty cool to me,” he said. “In the beginning, it was quite tough. Three years later I’ve caught up, but I still have a lot to learn.”

    Ultimately, KBase aims to interweave huge amounts of data with the right tools and user interface to enable bench scientists without programming backgrounds to answer the kinds of complex questions needed to solve the energy and environmental issues of our time.

    “We can gain systematic understanding of a biological process much faster, and also have a much deeper understanding,” Yoo said, “so we can engineer plant organisms or bacteria to improve productivity, biomass yield—and then use that information for biodesign.”

    KBase is funded by the DOE’s Office of Science. The Office of Science (SC) is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

    See the full article here.

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world.Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
    i1

    ScienceSprings relies on technology from

    MAINGEAR computers

    Lenovo
    Lenovo

    Dell
    Dell

     
  • richardmitnick 10:49 am on August 18, 2014 Permalink | Reply
    Tags: , Brookhaven National Labs, Ferroelectrics   

    From Brookhaven Lab: “Promising Ferroelectric Materials Suffer From Unexpected Electric Polarizations” 

    Brookhaven Lab

    August 18, 2014
    Justin Eure, (631) 344-2347 or Peter Genzer, (631) 344-3174

    Brookhaven Lab scientists find surprising locked charge polarizations that impede performance in next-gen materials that could otherwise revolutionize data-driven devices.

    Electronic devices with unprecedented efficiency and data storage may someday run on ferroelectrics—remarkable materials that use built-in electric polarizations to read and write digital information, outperforming the magnets inside most popular data-driven technology. But ferroelectrics must first overcome a few key stumbling blocks, including a curious habit of “forgetting” stored data.

    three
    Scientists and study coauthors from Brookhaven Lab’s Condensed Matter Physics and Materials Science Department stand beside a transmission electron microscope (TEM) capable of capturing nanoscale structures. From left: Myung-Geun Han, Yimei Zhu, and Lijun Wu.

    “For the first time, we could see these unusual and jagged polarizations mapped out in real space and real time.”
    — Brookhaven Lab scientist and study coauthor Myung-Geun Han

    Now, scientists at the U.S. Department of Energy’s Brookhaven National Laboratory have discovered nanoscale asymmetries and charge preferences hidden within ferroelectrics that may explain their operational limits.

    “The positive or negative polarizations in these ferroelectric materials should be incredibly easy to switch, but the reality is much stranger,” said Brookhaven Lab physicist Myung-Geun Han, lead author on the new study. “To our surprise, opposing electronic configurations only allowed for polarization in one direction—a non-starter for reading and writing data.”

    The researchers used a suite of state-of-the-art techniques—including real-time electrical biasing, electron holography, and electron-beam-induced current measurements—to reveal never-before-seen electric field distributions in ferroelectric thin films, which were custom-grown at Yale University. The results, published in Nature Communications, open new pathways for ferroelectric technology.

    Physics of Flipping

    land
    electrostatic potential landscapes

    Electrostatic potential landscapes reconstructed from electron holography data with 15 volts of positive or negative current applied to the substrate (Nb-STO). The much steeper potential drop from the +15 V signifies a higher electric field, whereas the -15 V yielded a much flatter curve—indicating the charge asymmetry within the material.

    Most electronic devices rely on ferromagnetism to read and write data. Each so-called ferromagnetic domain contains a north or south magnetic polarity, which translates into the flipping 1 or 0 of the binary code underlying all digital information. But ferromagnetic operations not only require large electric current, but the magnets can flip each other like dominoes when packed together too tightly—effectively erasing any data.

    Ferroelectrics, however, use positive or negative electric charge to render digital code. Crucially, they can be packed together with domains spanning just a few atoms and require only a tiny voltage kick to flip the charge, storing much more information with much greater efficiency.

    “But ferroelectric commercialization is held up by material fatigue, sudden polarization reversal, and intrinsic charge preferences,” said Brookhaven Lab physicist and study coauthor Yimei Zhu. “We suspected that the origin of these issues was in the atomic interactions along the material’s interface—where the ferroelectric thin film sits on a substrate.”

    Interface Exploration
    switch
    These dark-field transmission electron microscopy (TEM) images show ferroelectric domain switching under various external biases. Without external current, the PZT film is split—the two opposing polarization are arranged in a head-to-head configuration. Crucially, with –10 V applied in the bottom image, the domains near the PZT/Nb-STO interface fail to switch.

    The scientists examined ferroelectric films of lead, zirconium, and titanium oxide grown on conductive substrates of strontium, and titanium oxide with a small amount of niobium—chosen because it exhibits large polarization values with well-defined directions, either up or down. The challenge was mapping the internal electric fields in materials thousands of times thinner than a human hair under actual operating conditions.

    Brookhaven scientists hunted down the suspected interface quirks using electron holography. In this technique, a transmission electron microscope (TEM) fired 200,000-volt electron wave packets through the sample with billionth-of-a-meter precision. Negative and positive electric fields inside the ferroelectric film then attracted or repelled the electron wave and slightly changed its direction. Tracking the way the beam bent throughout the ferroelectric film revealed its hidden charges.

    “Rather than an evenly distributed electric field, the bending electron waves revealed non-uniform and unidirectional electric fields that induced unstable, head-to-head domain configurations,” Han said. “For the first time, we could see these unusual and jagged polarizations mapped out in real space and real time.”

    These opposing polarizations—like rival football teams squaring off aggressively at the line of scrimmage—surprised scientists and challenged assumptions about the ferroelectric phenomenon.

    “These results were totally unexpected based on the present understanding of ferroelectrics,” Han said.

    The asymmetries were further confirmed by measurements of electron-beam-induced current. When a focused electron beam struck the ferroelectric sample, electric fields within the film-substrate interface revealed themselves by generating additional current. Other techniques, including piezoresponse force microscopy—in which a sub-nanometer tip induces a reaction by pressing against the ferroelectric—also confirmed the strange domains.

    “Each technique demonstrated this intrinsic polarization preference, likely the origin of the back-switching and poor coding performance in these ferroelectrics,” Han said. “But these domain structures should require a lot of energy and thus be very unstable. The interface effect alone cannot explain their existence.”
    Missing Oxygen

    The scientists used another ultra-precise technique to probe the material’s interface: electron energy loss spectroscopy (EELS). By measuring the energy deposited by an electron beam in specific locations—a kind of electronic fingerprint—the scientists determined the material’s chemical composition.

    “We suspect that more oxygen could be missing near the surface of the thin films, creating electron pockets that may neutralize positive charges at the domain walls,” Han said. “This oxygen deficiency naturally forms in the material, and it could explain the stabilization of head-to-head domains.”

    This electron-swapping oxygen deficiency—and its negative effects on reliably storing data—might be corrected by additional engineering, Han said. For example, incorporating a “sacrificial layer” between the ferroelectric and the substrate could help block the interface interactions. In fact, the study may inspire new ferroelectrics that either exploit or overcome this unexpected charge phenomenon.

    Other authors include Lijun Wu and Marvin A. Schofield of Brookhaven Lab; Matthew S. J. Marshall, Jason Hoffman, Frederick J. Walker, and Charles H. Ahn of the Yale University Department of Applied Physics and Center for Research on Interfaces Structures and Phenomena; Toshihiro Aoki of JEOL USA Inc.; and Ray Twesten of Gatan Inc.

    The samples used for transmission electron microscopy (TEM) were prepared by Kim Kisslinger at Brookhaven Lab’s Center for Functional Nanomaterials, a U.S. Department of Energy user facility.

    The research was supported by the U.S. Department of Energy’s Office of Science.

    See the full article here.

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world.Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
    i1

    ScienceSprings relies on technology from

    MAINGEAR computers

    Lenovo
    Lenovo

    Dell
    Dell

     
  • richardmitnick 9:09 am on August 15, 2014 Permalink | Reply
    Tags: , Brookhaven National Labs, Condensed Matter Physics,   

    From Brookhaven Lab: “New Grant to Aid Search for the Secrets of Superconductivity” 

    Brookhaven Lab

    August 12, 2014
    Karen McNulty Walsh

    Research aimed at unlocking the secrets of high-temperature superconductivity at the U.S. Department of Energy’s Brookhaven National Laboratory will get a boost from a new grant awarded to Ivan Bozovic, a Brookhaven physicist and an Adjunct Professor at Yale University, by the Gordon and Betty Moore Foundation. Bozovic will receive $1.9 million over five years as part of the Moore Materials Synthesis Investigators program to continue the meticulous assembly and manipulation of superconducting thin films and the exploration of factors underlying these remarkable materials’ ability to carry electric current with no energy loss.

    “I am very grateful for this grant, which recognizes the importance of methodical work that slowly but steadily improves materials synthesis techniques and sample quality,” Bozovic said. Such quality is essential to uncover subtle effects in high-temperature superconductors, which, Bozovic notes, can be masked by impurities. “The better the samples, the more precise and revealing our experiments can be — and the greater their potential for new insights and discoveries,” he said.

    To achieve such precision, Bozovic uses a one-of-a-kind molecular-beam epitaxy (MBE) machine that he built and continues to improve to fabricate superconducting thin films one atomic layer at a time. He and collaborators have used the machine to assemble more than 2,000 thin film samples and conduct hundreds of scientific experiments. He also contributes to research at Brookhaven’s Center for Emergent Superconductivity, one of DOE’s Energy Frontier Research Centers, which recently received renewed funding.

    “I am very grateful for this grant, which recognizes the importance of methodical work that slowly but steadily improves materials synthesis techniques and sample quality.”
    — Brookhaven physicist Ivan Bozovic

    ib

    Leveraging his atomic-layer-by-layer synthesis technique, Bozovic made a series of discoveries related to interface superconductivity, bringing it to the forefront of research in Condensed Matter Physics. He showed that superfluid can be confined to a single atomic layer at the interface of two materials, neither of which is superconducting. In another important experiment, he proved that electron pairs exist on both sides of the superconductor-to-insulator transition an important insight into the mysterious nature of the high-temperature superconductivity phenomenon.

    Bozovic is one of only 12 scientists to be awarded funding through the Moore Materials Synthesis Investigators program, part of the foundation’s Emerging Phenomena in Quantum Systems (EPiQS) initiative. Quantum materials, the Foundation notes, are substances in which the collective behavior of electrons leads to many complex and unexpected emergent phenomena, superconductivity being a prominent example.

    In announcing the grantees, the Foundation stated:

    “Our approach is to focus on some of the field’s leading scientists; to allow these scientists the freedom to explore and the flexibility to change research directions; and to incentivize sample sharing within the EPiQS program and beyond…We believe that our programs will lead to discoveries of new quantum materials with emergent electronic properties as well as an increase in the availability of top-quality samples to the experimental community.”

    Bozovic earned a Ph.D. in physics from the University of Belgrade in Yugoslavia in 1975. He remained there until 1985 and served as a professor and the Head of the Physics Department. From 1986 until 1988, he worked at the Applied Physics Department at Stanford University. He was a senior research scientist at Varian Research Center in Palo Alto, California, 1989 to 1998, and the chief technical officer and principal scientist for Oxxel GmbH in Germany 1998 to 2002. He joined Brookhaven as a senior scientist and the leader of the Molecular Beam Epitaxy group in 2003. In 2012 he was a co-recipient of the Bernd T. Matthias Prize for Superconducting Materials, and in 2013 was chosen to give the Max Planck Lecture at MPI-Stuttgart, Germany. His research results have been published in more than 200 research papers and cited more than 6,500 times. Many of these were published in the highest-impact journals such as Nature, Science, and Nature Materials. Bozovic is a Fellow of APS and of SPIE, and a Foreign Member of Serbian Academy of Science and Arts.

    Bozovic’s research at Brookhaven is supported by the DOE Office of Science. The Moore Foundation grant will be awarded to him by way of his adjunct appointment at Yale University.

    See the full article here.

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world.Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
    i1

    ScienceSprings relies on technology from

    MAINGEAR computers

    Lenovo
    Lenovo

    Dell
    Dell

     
  • richardmitnick 8:39 am on August 11, 2014 Permalink | Reply
    Tags: , Brookhaven National Labs, ,   

    From Brookhaven Lab: “Dark Interactions Workshop Brings Global Physicists to Brookhaven” 

    Brookhaven Lab

    August 11, 2014
    Chelsea Whyte

    people
    Nearly 80 physicists — representing experiments from laboratories including Thomas Jefferson National Accelrator Facility, the Large Hadron Collider, the Mainz Microtron, SLAC National Accelerator Laboratory, KEK, and universities involved in other dark particle detector experiments — attended the Dark Interactions Workshop at Brookhaven National Laboratory in June 2014.

    For three days in June, physicists from around the world came together at the U.S. Department of Energy’s Brookhaven National Laboratory for the inaugural physics workshop “Dark Interactions: Perspectives from Theory and Experiment,” chaired by Brookhaven physicist Ketevi Assamagan. He jointly organized the workshop with Brookhaven physicist Hooman Davoudiasl and Stony Brook University assistant professor of physics Rouven Essig.

    The goal of the workshop was to review and discuss the theoretical context as well as the status and future of the searches for dark sector particles, such as dark vector bosons, and the implications for dark matter.

    “We hope to continue this meeting in the years to come. We gain a lot by sharing ideas between theorists and experimentalists,” Assamagan said. Nearly 80 physicists attended the workshop to hear presentations that covered a range of topics on the frontier of new physics: the theories and experiments trying to track down dark matter, the mysterious substance that neither emits nor absorbs light, but is theorized to comprise nearly 27% of the cosmos.

    So far, despite the tremendous amount of evidence for the existence of dark matter, nobody knows its identity; but if anyone is going to devise a way to determine its makeup, it could be one of the physicists in attendance at the workshop. Over the course of several days, they discussed theoretical motivations for the search for dark matter, and several experiments already looking for the mystery matter, including:

    The DarkLight, HPS, and APEX experiments at Thomas Jefferson National Accelerator Facility;
    The CMS, ATLAS, ALICE and LHCb experiments at the Large Hadron Collider in Geneva, Switzerland;
    The A1 collaboration at the Mainz Microtron;
    Dark photon and low-mass Higgs searches at the BaBar detector at the SLAC National Accelerator Laboratory;
    The Belle Collaboration at KEK
    The PHENIX experiment at Brookhaven National Laboratory
    The Muon g-2 experiment [at Fermilab]
    The Axion Dark Matter Experiment at the University of Washington
    LHC experiments, namely ATLAS, CMS, ALICE and LHCb also contribute to the searches for Dark Matter. Ketevi Assamagan (BNL) and Oliver Keith Baker (Yale University) are working on some of the ATLAS analyses that may provide clues into the nature of Dark Matter.

    “It’s hard to believe dark matter is an idea that’s 80 years old,” said Professor David Brown of the University of Louisville. “Of course, we still don’t know what dark matter is. But colliders let us search for dark particles.”

    “Understanding the nature of dark matter poses one of the most urgent problems for our fundamental description of the Universe,” Davoudiasl said. “Interactive meetings, like DI2014, allow us to share various points of view on the scope of theoretical and experimental opportunities, as well as challenges, that lie ahead in the quest to uncover the properties of dark matter.”

    The attendees shared results from experiments all over the world, with tantalizing hints at the nature of dark matter. And as they continue this search, coordination across disciplines and national borders remains key to collaboration.

    “An enormous amount of progress has been made over the last few years in the search for dark matter and dark forces,” Essig said. “All of us hope that the current generation of experiments will be successful at finding new physics.”

    See the full article here.

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world.Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
    i1

    ScienceSprings relies on technology from

    MAINGEAR computers

    Lenovo
    Lenovo

    Dell
    Dell

     
  • richardmitnick 9:13 am on August 1, 2014 Permalink | Reply
    Tags: , Brookhaven National Labs, ,   

    From Brookhaven Lab: “Nanostructured Metal-Oxide Catalyst Efficiently Converts CO2 to Methanol” 

    Brookhaven Lab

    July 31, 2014
    Karen McNulty Walsh, (631) 344-8350 or Peter Genzer, (631) 344-3174printer iconPrint

    Highly reactive sites at interface of two nanoscale components could help overcome hurdle of using CO2 as a starting point in producing useful products

    people
    Dario Stacchiola and Kumudu Mudiyanselage make notes in the data log while Fang Xu (seated) and Jose Rodriguez view microscopic images of the catalyst and Ping Liu and Sanjaya Senanayake adjust the ambient-pressure scanning tunneling microscope. No image credit

    Scientists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory have discovered a new catalytic system for converting carbon dioxide (CO2) to methanol—a key commodity used to create a wide range of industrial chemicals and fuels. With significantly higher activity than other catalysts now in use, the new system could make it easier to get normally unreactive CO2 to participate in these reactions.

    “Developing an effective catalyst for synthesizing methanol from CO2 could greatly expand the use of this abundant gas as an economical feedstock,” said Brookhaven chemist Jose Rodriguez, who led the research. It’s even possible to imagine a future in which such catalysts help mitigate the accumulation of this greenhouse gas, by capturing CO2 emitted from methanol-powered combustion engines and fuel cells, and recycling it to synthesize new fuel.

    That future, of course, will be determined by a variety of factors, including economics. “Our basic research studies are focused on the science—the discovery of how such catalysts work, and the use of this knowledge to improve their activity and selectivity,” Rodriguez emphasized.

    The research team, which included scientists from Brookhaven, the University of Seville in Spain, and Central University of Venezuela, describes their results in the August 1, 2014, issue of the journal Science.

    New tools for discovery

    fu
    Fang Xu, a Stony Brook University PhD student working with the Brookhaven Lab team on studies to identify more effective catalysts for industrial processes, peers into the ambient-pressure scanning tunneling microscope used in these experiments.

    Because CO2 is normally such a reluctant participant in chemical reactions, interacting weakly with most catalysts, it’s also rather difficult to study. These studies required the use of newly developed in-situ (or on-site, meaning under reaction conditions) imaging and chemical “fingerprinting” techniques. These techniques allowed the scientists to peer into the dynamic evolution of a variety of catalysts as they operated in real time. The scientists also used computational modeling at the University of Seville and the Barcelona Supercomputing Center to provide a molecular description of the methanol synthesis mechanism.

    The team was particularly interested in exploring a catalyst composed of copper and ceria (cerium-oxide) nanoparticles, sometimes also mixed with titania. The scientists’ previous studies with such metal-oxide nanoparticle catalysts have demonstrated their exceptional reactivity in a variety of reactions. In those studies, the interfaces of the two types of nanoparticles turned out to be critical to the reactivity of the catalysts, with highly reactive sites forming at regions where the two phases meet.

    To explore the reactivity of such dual particle catalytic systems in converting CO2 to methanol, the scientists used spectroscopic techniques to investigate the interaction of CO2 with plain copper, plain cerium-oxide, and cerium-oxide/copper surfaces at a range of reaction temperatures and pressures. Chemical fingerprinting was combined with computational modeling to reveal the most probable progression of intermediates as the reaction from CO2 to methanol proceeded.

    These studies revealed that the metal component of the catalysts alone could not carry out all the chemical steps necessary for the production of methanol. The most effective binding and activation of CO2 occurred at the interfaces between metal and oxide nanoparticles in the cerium-oxide/copper catalytic system.

    “The key active sites for the chemical transformations involved atoms from the metal [copper] and oxide [ceria or ceria/titania] phases,” said Jesus Graciani, a chemist from the University of Seville and first author on the paper. The resulting catalyst converts CO2 to methanol more than a thousand times faster than plain copper particles, and almost 90 times faster than a common copper/zinc-oxide catalyst currently in industrial use.

    two
    Scanning tunneling microscope image of a cerium-oxide and copper catalyst (CeOx-Cu) used in the transformation of carbon dioxide (CO2) and hydrogen (H2) gases to methanol (CH3OH) and water (H2O). In the presence of hydrogen, the Ce4+ and Cu+1 are reduced to Ce3+ and Cu0 with a change in the structure of the catalyst surface.

    This study illustrates the substantial benefits that can be obtained by properly tuning the properties of a metal-oxide interface in catalysts for methanol synthesis.

    “It is a very interesting step, and appears to create a new strategy for the design of highly active catalysts for the synthesis of alcohols and related molecules,” said Brookhaven Lab Chemistry Department Chair Alex Harris.

    The work at Brookhaven Lab was supported by the DOE Office of Science. The studies performed at the University of Seville were funded by the Ministerio de Economía y Competitividad of Spain and the European Regional Development Fund. The Instituto de Tecnologia Venezolana para el Petroleo supported part of the work carried out at the Central University of Venezuela.

    Brookhaven National Laboratory is supported by the Office of Science of the U.S. Department of Energy. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

    See the full article, with video, here.

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world.Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
    i1


    ScienceSprings is powered by MAINGEAR computers

     
  • richardmitnick 11:28 am on July 28, 2014 Permalink | Reply
    Tags: , , Brookhaven National Labs,   

    From Brookhaven Lab: “Understanding the Source of Extra-large Capacities in Promising Li-ion Battery Electrodes” 

    Brookhaven Lab

    July 28, 2014
    Laura Mgrdichian

    Lithium (Li) ion batteries power almost all of the portable electronic devices that we use everyday, including smart phones, cameras, toys, and even electric cars. Researchers across the globe are working to find materials that will lead to safe, cheap, long-lasting, and powerful Li-ion batteries.

    Working at various U.S. Department of Energy light source facilities and at Cambridge and Stony Brook universities, a group of researchers recently studied a class of Li-ion battery electrodes that have capacities much greater than those of the materials used in today’s batteries. The researchers wanted to determine why these materials can often store more charge than theory predicts.

    path
    A summary of the three-stage reaction pathway of the ruthenium-oxide-lithium battery system.

    The authors chose ruthenium oxide (RuO2) as a model system to study these so-called “conversion materials,” named because they undergo large structural changes when reacting with lithium ions, reversibly forming metal nanoparticles and salts (here Ru and Li2O). These reactions are very different from those that occur in conventional electrodes, which store charge by allowing Li ions to nestle into spaces within the crystal lattice.

    “Our investigation identified the source of the additional capacity found for RuO2, and has also yielded a protocol for studying the ‘passivation layer’ that forms on battery electrodes, which protects the electrolyte from undergoing further decomposition reactions in subsequent charge-discharge cycles,” said the study’s corresponding researcher, Clare Grey, a professor in the chemistry departments at Cambridge and Stony Brook universities. “Understanding the structures of these passivation layers is key to making batteries that last long enough for use in applications such as transportation and power-grid storage.”

    At Brookhaven National Laboratory’s National Synchrotron Light Source, the team studied their samples using x-ray absorption near-edge structure (XANES) and extended x-ray absorption fine structure (EXAFS). At the Advanced Photon Source at Argonne National Laboratory, they used two additional techniques, high-resolution x-ray diffraction (XRD) and scattering pair distribution function (PDF) analysis, to extract information on the electronic and long/short-range structural changes of the RuO2 electrode in real time as the battery was discharged and charged. Using these methods, the team showed that RuO2 was reduced to Ru nanoparticles and Li2O via the formation of intermediate phases, LixRuO2.

    Since this did not explain the source of the additional charge-storage mechanism, the group used another technique, high-resolution solid-state nuclear magnetic resonance (NMR). This method involves subjecting a sample to a magnetic field and measuring the response of the nuclei within the sample. It can yield specific information on the chemical compositions and local structures, and is particularly useful for studying compounds that contain only “light” elements, such as hydrogen (H), Li, and oxygen (O), which are difficult to detect using XRD. The NMR data showed that the major contributor to the capacity is the formation of LiOH, which reversibly converts to Li2O and LiH. Minor contributors to the capacity come from Li storage on the Ru nanoparticle surfaces, forming a LixRu alloy, and the decomposition of the electrolyte. The latter, however, ultimately causes the capacity to diminish and will result in the death of the battery following multiple charge cycles.

    Scientists from the University of Cambridge, Brookhaven National Laboratory, Argonne National Laboratory, and Stony Brook University conducted this research. It was published in the December 2013 issue of Nature Materials, 12, 1130-1136. The paper is titled Origin of additional capacities in metal oxide lithium-ion battery electrodes, and the authors are Yan-Yan Hu, Zigeng Liu, Kyung-Wan Nam, Olaf J. Borkiewicz, Jun Cheng, Xiao Hua, Matthew T. Dunstan, Xiqian Yu, Kamila M. Wiaderek, Lin-Shu Du, Karena W. Chapman, Peter J. Chupas, Xiao-Qing Yang and Clare P. Grey.

    See the full article here.

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world.Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
    i1


    ScienceSprings is powered by MAINGEAR computers

     
  • richardmitnick 11:29 am on July 24, 2014 Permalink | Reply
    Tags: , , , , Brookhaven National Labs, ,   

    From Brookhaven Lab: “Instrumentation Division Nears Production Phase for LSST Camera Sensors” 

    Brookhaven Lab

    July 21, 2014
    Rebecca Harrington

    Precision assembly is required to capture the clearest and most extensive picture of the cosmos

    A single sensor for the world’s largest digital camera detected light making its way through wind, air turbulence, and Earth’s atmosphere, successfully converting the light into a glimpse of the galactic wonders that this delicate instrument will eventually capture as it scans the night sky. When installed in the camera of the Large Synoptic Survey Telescope (LSST), these sensors will convert light captured from distant galaxies into digital information that will provide unprecedented insight into our understanding of the universe.

    two
    Design Engineer Justine Haupt (left) and Postdoctoral Research Associate Dajun Huang (right) prepare a test chamber that scientists in the Instrumentation Division are are using to evaluate the digital sensors they are designing for the Large Synoptic Survey Telescope, which is scheduled to see “first light” in 2020, and start surveying in 2022.

    LSST Telescope
    LSST

    But the sensor wasn’t on the telescope yet; it was in a clean room at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory. And the “atmosphere” was being projected from a custom piece of glass made to replicate what the sensor will actually see once it is part of the camera inside the LSST, which every three days will survey the entire night sky visible from its location atop a mountain in Chile. The meticulous laboratory test at Brookhaven was one of many that scientists in the Lab’s Instrumentation Division are conducting on the 201 sensors they are designing for the digital “film” of the telescope’s camera.

    Scheduled to see “first light” in 2020, and start surveying in 2022, the LSST will ultimately survey 20 billion galaxies and 17 billion stars in a 10-year period. . In working on sensors for the camera, Brookhaven is partnering with dozens of public and private organizations, including universities, national laboratories, and Google, Inc., to make the LSST a reality. The project is jointly sponsored by the National Science Foundation (NSF) and DOE’s Office of Science. NSF leads the overall LSST effort, while DOE is responsible for providing the camera, with the DOE-supported effort led by the SLAC National Accelerator Laboratory.

    I think it will be an important chapter in the history of physics.
    Paul O’Connor, Brookhaven Senior Scientist leading the LSST camera team at Brookhaven

    The data gathered from those distant galaxies will offer scientists insight into the seemingly unreal: the dark matter and dark energy that in fact comprise more than 95 percent of our universe (the planets, stars, and other visible matter making up a mere 5 percent). Dark energy, the mysterious force that is accelerating the universe’s expansion, only manifests itself by its effects on large-scale cosmic structures. Dark matter, invisible on its own, can be measured by observing how light bends around it. Understanding these strange concepts and their role in cosmic acceleration are among the “science drivers” recently identified by a panel reviewing priorities in particle physics, which recommended that DOE’s work on the LSST camera go forward no matter what funding scenario the field may face.

    “This question of dark energy and dark matter is so compelling,” said Senior Scientist Paul O’Connor, who’s leading the LSST camera team at Brookhaven. “There’s incontrovertible evidence that these are the major constituents of the universe; they don’t fit into the rest of physics.”

    LSST’s incredible precision and sensitivity will give scientists access to both.

    To unlock the mysteries of dark energy, LSST needs to be able to measure redshift, a phenomenon observed when the wavelengths of light emitted by galaxies receding at the distant edges of space appear to stretch out, or shift to the red end of the light spectrum. Most galaxies to be detected by LSST are faint and far away, at the limits of current sensor technology for measuring redshifts. So O’Connor said his team needed to design the LSST camera sensors with a much thicker layer of silicon and entirely new electronics.

    “Making a contribution on the experimental end exploring these phenomena is quite satisfying,” O’Connor said. “I think it will be an important chapter in the history of physics.”

    But the LSST won’t just be for scientists. The general public will be able to access its images through planned projects such as adopting a patch of sky to monitor and track changes, and interacting with a time-lapse movie shown in science centers depicting a decade of observation. The telescope’s imaging powers will also join the host of other instruments used to detect exploding supernovae, and asteroids that could hit our planet, giving scientists more warning before they come close to Earth.
    Building the World’s Largest Digital Camera

    tower
    A design of a single raft tower housing the charge-coupled devices (CCDs) — sensors that convert light captured by the telescope into an electrical charge representing a specific detail that a computer can turn into a digital picture. The full camera will have 21 raft towers.

    The LSST sensors that the Brookhaven scientists are designing, building, and testing are known as charge-coupled devices (CCDs). Each pixel on a CCD converts light captured by the telescope into an electrical charge representing a specific detail that a computer can turn into a digital picture. LSST’s CCDs will capture deep space in unprecedented detail with 3.2-gigapixel sensors — that’s nearly 200 times larger than a high-end consumer camera.

    Each CCD operates individually, but they will all work together to render a complete image. Nine CCDs sit in a “raft,” or support structure, with their electronics packed underneath. The modularity that the LSST gains because of these rafts will allow for the incredibly quick sky surveys — reading 3 billion pixels in 2 seconds. It will also enable easier telescope maintenance since scientists can fix a single CCD instead of fixing the whole system, which will come in handy when the rafts are housed in a vacuum chamber kept at -100 degrees Celsius inside the telescope.

    The modularity of the rafts will also be a benefit during the installation and testing of the telescope base. Typically, when scientists build a telescope, they use a placeholder camera to test whether the mount and optics are working properly. Later, they install the full camera and sensors, after those instruments have undergone their own functional tests. But O’Connor said the LSST team will be able to use a single raft for initial testing on the mountain, allowing the scientists to measure the success of these components on the telescope itself.

    “We’re now finding some of the instrument effects emerging as we put the CCDs together at the laboratory phase, so we can prepare the type of software we need now,” O’Connor said. “But the sky tells you things you can’t easily measure in the lab.”

    To capture the clearest and most extensive picture of the cosmos, the CCDs must lie perfectly flat and have no more than a 250 micron (millionth of a meter) space between them. This requires painstaking assembly at Brookhaven, but at some point the sensors have to get to California to join the other parts, and then to Chile for operation. Mechanical engineers at Brookhaven are designing a stabilized shipping container to transport the sensitive CCDs across the country and continents.

    By the end of 2014, O’Connor said, his team hopes to have the first fully functional raft completed and tested. After that, he said, it will take four years to build and test the rest of the CCD rafts, which is on track to meet the “first light” deadline.

    “We have a well-defined job now. We can do our part while the other teams building the rest of the LSST do theirs,” O’Connor said. “This is a big project. This is the way science is going to solve big problems.”

    For more information, go to http://www.lsst.org.

    DOE’s Office of High Energy Physics funds the LSST camera development.

    See the full article here.

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world.Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
    i1


    ScienceSprings is powered by MAINGEAR computers

     
  • richardmitnick 5:37 am on June 24, 2014 Permalink | Reply
    Tags: , , Brookhaven National Labs   

    From Brookhaven Lab: “Protons Power Protein Portal to Push Zinc Out of Cells” 

    Brookhaven Lab

    June 22, 2014
    Contacts: Chelsea Whyte, (631) 344-8671 or Peter Genzer, (631) 344-3174

    Protein, linked to type 2 diabetes, prevents zinc toxicity

    Researchers at The Johns Hopkins University report they have deciphered the inner workings of a protein called YiiP that prevents the lethal buildup of zinc inside bacteria. They say understanding YiiP’s movements will help in the design of drugs aimed at modifying the behavior of ZnT proteins, eight human proteins that are similar to YiiP, which play important roles in hormone secretion and in signaling between neurons.

    Certain mutations in one of them, ZnT8, have been associated with an increased susceptibility to type 2 diabetes, but mutations that destroy its function seem to be protective.

    A summary of the research will be published online in the journal Nature on June 22.

    “Zinc is necessary for life. It requires transporter proteins to get into and out of cells, where it does its work,” says Dax Fu Ph.D., , an associate professor of physiology. “If the transporter proteins malfunction, zinc concentrations can reach toxic levels. This study shows us how zinc-removing proteins work.”

    image
    Upper and Middle Panels: Atomic details of zinc binding to the zinc transporter protein, known as YiiP. Lower panel: A cartoon illustrating how zinc binding may change the protein shape to regulate the coordination geometry of the active site for zinc transport (shown as a tetrahedron in middle panel).

    Zinc is needed to activate genes and to enable many proteins to function. In pancreatic beta cells, high concentrations of zinc are found inside the packages of insulin that they produce, although its precise role there is unknown.

    YiiP is found partially embedded in the membranes of the bacterium E. coli, where it has a similar function to the ZnT human proteins. In a previous study, Fu’s group mapped YiiP’s atomic structure and found that there is a zinc-binding pocket in its center. But how a single pocket could transport zinc from one side of a membrane to the other was a mystery, he says.

    “Understanding the way [this] protein works, especially which segments of the protein do what, will help us design better drugs to moderate its activity wherever it is found.”
    — former Brookhaven biochemist Dax Fu, now an associate professor of physiology at The Johns Hopkins University School of Medicine

    Knowing that the protein lets one hydrogen ion — or proton — into the cell for every zinc ion it sends out, the team suspected there was a hidden channel that opened up to allow the ions to switch places.

    To test this idea and to find out which inner segments of the protein make up the channel, the team collaborated with scientists at Brookhaven National Laboratory to shine intense X-rays at the protein while it was immersed in water. The X-rays caused the water molecules to split into two components: hydrogen atoms and hydroxyl radicals. When the hidden channel within the protein opened up, the hydroxyl radicals bonded with the exposed protein segments, “marking” the ones that created the channel.

    The researchers then cut up YiiP using enzymes and analyzed the resulting pieces in an instrument that helped them identify the makeup of each piece. By comparing those pieces to pieces of YiiP that had not been exposed to hydroxyl radicals, the researchers could tell which segments create the channel.

    Using this and other information, the scientists were able to figure out how the protein works.
    Fast Facts

    Zinc is a mineral required for life, but large amounts of it can be toxic.
    Transporter proteins keep levels safe by pushing zinc out of the cell.
    New research reveals how transporter proteins use protons as a power source for moving zinc.
    Understanding mechanics of transporter proteins may advance design of diabetes drugs.

    Outside the membrane is an abundance of protons, with a lower concentration inside the membrane, creating what is known as a concentration gradient. The protons want to flow “down” this gradient into the cell, like water following gravity down a waterfall, says Fu. Thus, when the central pocket of the transporter protein is open to the outside, a proton will bind to the pocket.

    “When the protons move from a place of high concentration to low concentration, they generate a force like falling water does,” he says. The protein harnesses this force to change its shape, cutting off the pocket’s access to the outside environment and opening up its access to the inside. There, the proton will continue its “fall” by unbinding from the pocket and entering the inside space.

    Once it has released the proton, the pocket is free to bind to zinc. This binding again changes the protein’s shape, shutting off the pocket’s access to the inside of the membrane and once again exposing it to the outside. A proton then drives the zinc ion out of the pocket, and the cycle continues.

    “Understanding the way the protein works, especially which segments of the protein do what, will help us design better drugs to moderate its activity wherever it is found,” says Fu.

    Other authors of the report include Jie Cheng of the Johns Hopkins University School of Medicine; Sayan Gupta, Rhijuta D’Mello and Mark Chance of Case Western Reserve University; and Jin Chai of Brookhaven National Laboratory.

    This work was supported by grants from the National Institute of General Medical Sciences (R01GM065137), the National Institute of Biomedical Imaging and Bioengineering (P30-EB-09998, R01-EB-09688), and the U.S. Department of Energy

    See the full article here.

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world.Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
    i1


    ScienceSprings is powered by MAINGEAR computers

     
  • richardmitnick 3:45 pm on June 16, 2014 Permalink | Reply
    Tags: , Brookhaven National Labs, ,   

    Fro Brookhaven Lab: “New Evidence for Oceans of Water Deep in the Earth” 

    Brookhaven Lab

    June 13, 2014
    Karen McNulty Walsh, (631) 344-8350 or Peter Genzer, (631) 344-3174printer iconPrint

    Water bound in mantle rock alters our view of the Earth’s composition

    Researchers from Northwestern University and the University of New Mexico report evidence for potentially oceans worth of water deep beneath the United States. Though not in the familiar liquid form — the ingredients for water are bound up in rock deep in the Earth’s mantle — the discovery may represent the planet’s largest water reservoir.

    earth
    Structure of the Earth

    The presence of liquid water on the surface is what makes our “blue planet” habitable, and scientists have long been trying to figure out just how much water may be cycling between Earth’s surface and interior reservoirs through plate tectonics.

    Northwestern geophysicist Steve Jacobsen and University of New Mexico seismologist Brandon Schmandt have found deep pockets of magma located about 400 miles beneath North America, a likely signature of the presence of water at these depths. The discovery suggests water from the Earth’s surface can be driven to such great depths by plate tectonics, eventually causing partial melting of the rocks found deep in the mantle.

    The findings, to be published June 13 in the journal Science, will aid scientists in understanding how the Earth formed, what its current composition and inner workings are and how much water is trapped in mantle rock.

    “Geological processes on the Earth’s surface, such as earthquakes or erupting volcanoes, are an expression of what is going on inside the Earth, out of our sight,” said Jacobsen, a co-author of the paper. “I think we are finally seeing evidence for a whole-Earth water cycle, which may help explain the vast amount of liquid water on the surface of our habitable planet. Scientists have been looking for this missing deep water for decades.”

    mntle
    A blue crystal of ringwoodite containing around one percent of H2O in its crystal structure is compressed to conditions of 700 km depth inside a diamond-anvil cell. Using a laser to heat the sample to temperatures over 1500C (orange spots), the ringwoodite transformed to minerals found in the lowermost mantle. Synchrotron-infrared spectra collected on beamline U2A at the NSLS reveal changes in the OH-absorption spectra that correspond to melt generation, which was also detected by seismic waves underneath most of North America.

    Scientists have long speculated that water is trapped in a rocky layer of the Earth’s mantle located between the lower mantle and upper mantle, at depths between 250 miles and 410 miles. Jacobsen and Schmandt are the first to provide direct evidence that there may be water in this area of the mantle, known as the “transition zone,” on a regional scale. The region extends across most of the interior of the United States.

    Schmandt, an assistant professor of geophysics at the University of New Mexico, uses seismic waves from earthquakes to investigate the structure of the deep crust and mantle. Jacobsen, an associate professor of Earth and planetary sciences at Northwestern’s Weinberg College of Arts and Sciences, uses observations in the laboratory to make predictions about geophysical processes occurring far beyond our direct observation.

    The study combined Jacobsen’s lab experiments in which he studies mantle rock under the simulated high pressures of 400 miles below the Earth’s surface with Schmandt’s observations using vast amounts of seismic data from the USArray, a dense network of more than 2,000 seismometers across the United States.

    Jacobsen’s and Schmandt’s findings converged to produce evidence that melting may occur about 400 miles deep in the Earth. H2O stored in mantle rocks, such as those containing the mineral ringwoodite, likely is the key to the process, the researchers said.

    “Melting of rock at this depth is remarkable because most melting in the mantle occurs much shallower, in the upper 50 miles,” said Schmandt, a co-author of the paper. “If there is a substantial amount of H2O in the transition zone, then some melting should take place in areas where there is flow into the lower mantle, and that is consistent with what we found.”

    If just one percent of the weight of mantle rock located in the transition zone is H2O, that would be equivalent to nearly three times the amount of water in our oceans, the researchers said.

    This water is not in a form familiar to us — it is not liquid, ice or vapor. This fourth form is water trapped inside the molecular structure of the minerals in the mantle rock. The weight of 250 miles of solid rock creates such high pressure, along with temperatures above 2,000 degrees Fahrenheit, that a water molecule splits to form a hydroxyl radical (OH), which can be bound into a mineral’s crystal structure.

    Schmandt and Jacobsen’s findings build on a discovery reported in March in the journal Nature in which scientists discovered a piece of the mineral ringwoodite inside a diamond brought up from a depth of 400 miles by a volcano in Brazil. That tiny piece of ringwoodite — the only sample in existence from within the Earth — contained a surprising amount of water bound in solid form in the mineral.

    “Whether or not this unique sample is representative of the Earth’s interior composition is not known, however,” Jacobsen said. “Now we have found evidence for extensive melting beneath North America at the same depths corresponding to the dehydration of ringwoodite, which is exactly what has been happening in my experiments.”

    For years, Jacobsen has been synthesizing ringwoodite, colored sapphire-like blue, in his Northwestern lab by reacting the green mineral olivine with water at high-pressure conditions. (The Earth’s upper mantle is rich in olivine.) He found that more than one percent of the weight of the ringwoodite’s crystal structure can consist of water — roughly the same amount of water as was found in the sample reported in the Nature paper.

    “The ringwoodite is like a sponge, soaking up water,” Jacobsen said. “There is something very special about the crystal structure of ringwoodite that allows it to attract hydrogen and trap water. This mineral can contain a lot of water under conditions of the deep mantle.”

    For the study reported in Science, Jacobsen subjected his synthesized ringwoodite to conditions around 400 miles below the Earth’s surface and found it forms small amounts of partial melt when pushed to these conditions. He detected the melt in experiments conducted at the Advanced Photon Source of Argonne National Laboratory and at the National Synchrotron Light Source of Brookhaven National Laboratory.

    Jacobsen uses small gem diamonds as hard anvils to compress minerals to deep-Earth conditions. “Because the diamond windows are transparent, we can look into the high-pressure device and watch reactions occurring at conditions of the deep mantle,” he said. “We used intense beams of X-rays, electrons and infrared light to study the chemical reactions taking place in the diamond cell.”

    Jacobsen’s findings produced the same evidence of partial melt, or magma, that Schmandt detected beneath North America using seismic waves. Because the deep mantle is beyond the direct observation of scientists, they use seismic waves — sound waves at different speeds — to image the interior of the Earth.

    “Seismic data from the USArray are giving us a clearer picture than ever before of the Earth’s internal structure beneath North America,” Schmandt said. “The melting we see appears to be driven by subduction — the downwelling of mantle material from the surface.”

    The melting the researchers have detected is called dehydration melting. Rocks in the transition zone can hold a lot of H2O, but rocks in the top of the lower mantle can hold almost none. The water contained within ringwoodite in the transition zone is forced out when it goes deeper (into the lower mantle) and forms a higher-pressure mineral called silicate perovskite, which cannot absorb the water. This causes the rock at the boundary between the transition zone and lower mantle to partially melt.

    “When a rock with a lot of H2O moves from the transition zone to the lower mantle it needs to get rid of the H2O somehow, so it melts a little bit,” Schmandt said. “This is called dehydration melting.”

    “Once the water is released, much of it may become trapped there in the transition zone,” Jacobsen added.

    Just a little bit of melt, about one percent, is detectible with the new array of seismometers aimed at this region of the mantle because the melt slows the speed of seismic waves, Schmandt said.

    The USArray is part of EarthScope, a program of the National Science Foundation that deploys thousands of seismic, GPS and other geophysical instruments to study the structure and evolution of the North American continent and the processes the cause earthquakes and volcanic eruptions.

    The National Science Foundation (grants EAR-0748797 and EAR-1215720) and the David and Lucile Packard Foundation supported the research.

    The paper is titled Dehydration melting at the top of the lower mantle. In addition to Jacobsen and Schmandt, other authors of the paper are Thorsten W. Becker, University of California, Los Angeles; Zhenxian Liu, Carnegie Institution of Washington; and Kenneth G. Dueker, the University of Wyoming

    See the full article here.

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world.Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
    i1


    ScienceSprings is powered by MAINGEAR computers

     
c
Compose new post
j
Next post/Next comment
k
Previous post/Previous comment
r
Reply
e
Edit
o
Show/Hide comments
t
Go to top
l
Go to login
h
Show/Hide help
shift + esc
Cancel
Follow

Get every new post delivered to your Inbox.

Join 332 other followers

%d bloggers like this: