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  • richardmitnick 3:38 pm on January 3, 2019 Permalink | Reply
    Tags: ALS, , , Electron spin, , SARPES detector, ,   

    From Lawrence Berkeley National Lab: “Revealing Hidden Spin: Unlocking New Paths Toward High-Temperature Superconductors” 

    Berkeley Logo

    From Lawrence Berkeley National Lab

    January 3, 2019

    Theresa Duque
    tnduque@lbl.gov
    (510) 495-2418

    Berkeley Lab researchers uncover insights into superconductivity, leading potentially to more efficient power transmission.

    1
    A research team led by Berkeley Lab’s Alessandra Lanzara (second from left) used a SARPES (spin- and angle-resolved photoemission spectroscopy) detector to uncover a distinct pattern of electron spins within the material. Co-lead authors are Kenneth Gotlieb (second from right) and Chiu-Yun Lin (right). The study’s co-authors include Chris Jozwiak of Berkeley Lab’s Advanced Light Source (left). (Credit: Peter DaSilva/Berkeley Lab)

    In the 1980s, the discovery of high-temperature superconductors known as cuprates upended a widely held theory that superconductor materials carry electrical current without resistance only at very low temperatures of around 30 Kelvin (or minus 406 degrees Fahrenheit). For decades since, researchers have been mystified by the ability of some cuprates to superconduct at temperatures of more than 100 Kelvin (minus 280 degrees Fahrenheit).

    Now, researchers at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) have unveiled a clue into the cuprates’ unusual properties – and the answer lies within an unexpected source: the electron spin. Their paper describing the research behind this discovery was published on Dec. 13 in the journal Science.

    Adding electron spin to the equation

    Every electron is like a tiny magnet that points in a certain direction. And electrons within most superconductor materials seem to follow their own inner compass. Rather than pointing in the same direction, their electron spins haphazardly point every which way – some up, some down, others left or right.

    2
    With the spin resolution enabled by SARPES, Berkeley Lab researchers revealed magnetic properties of Bi-2212 that have gone unnoticed in previous studies. (Credit: Kenneth Gotlieb, Chiu-Yun Lin, et al./Berkeley Lab)

    When scientists are developing new kinds of materials, they usually look at the materials’ electron spin, or the direction in which the electrons are pointing. But when it comes to making superconductors, condensed matter physicists haven’t traditionally focused on spin, because the conventionally held view was that all of the properties that make these materials unique were shaped only by the way in which two electrons interact with each other through what’s known as “electron correlation.”

    But when a research team led by Alessandra Lanzara, a faculty scientist in Berkeley Lab’s Materials Sciences Division and a Charles Kittel Professor of Physics at UC Berkeley, used a unique detector to measure samples of an exotic cuprate superconductor, Bi-2212 (bismuth strontium calcium copper oxide), with a powerful technique called SARPES (spin- and angle-resolved photoemission spectroscopy), they uncovered something that defied everything they had ever known about superconductors: a distinct pattern of electron spins within the material.

    “In other words, we discovered that there was a well-defined direction in which each electron was pointing given its momentum, a property also known as spin-momentum locking,” said Lanzara. “Finding it in high-temperature superconductors was a big surprise.”

    A new map for high-temperature superconductors

    In the world of superconductors, “high temperature” means that the material can conduct electricity without resistance at temperatures higher than expected but still in extremely cold temperatures far below zero degrees Fahrenheit. That’s because superconductors need to be extraordinarily cold to carry electricity without any resistance. At those low temperatures, electrons are able to move in sync with each other and not get knocked by jiggling atoms, causing electrical resistance.

    And within this special class of high-temperature superconductor materials, cuprates are some of the best performers, leading some researchers to believe that they have potential use as a new material for building super-efficient electrical wires that can carry power without any loss of electron momentum, said co-lead author Kenneth Gotlieb, who was a Ph.D. student in Lanzara’s lab at the time of the discovery. Understanding what makes some exotic cuprate superconductors such as Bi-2212 work at temperatures as high as 133 Kelvin (about -220 degrees Fahrenheit) could make it easier to realize a practical device.

    Among the very exotic materials that condensed matter physicists study, there are two kinds of electron interactions that give rise to novel properties for new materials, including superconductors, said Gotlieb. Scientists who have been studying cuprate superconductors have focused on just one of those interactions: electron correlation.

    The other kind of electron interaction found in exotic materials is “spin-orbit coupling” – the way in which the electron’s magnetic moment interacts with atoms in the material.

    Spin-orbit coupling was often neglected in the studies of cuprate superconductors, because many assumed that this kind of electron interaction would be weak when compared to electron correlation, said co-lead author Chiu-Yun Lin, a researcher in the Lab’s Materials Sciences Division and a Ph.D. student in the Department of Physics at UC Berkeley. So when they found the unusual spin pattern, Lin said that although they were pleasantly surprised by this initial finding, they still weren’t sure whether it was a “true” intrinsic property of the Bi-2212 material, or an external effect caused by the way the laser light interacted with the material in the experiment.

    Shining a light on electron spin with SARPES

    Over the course of nearly three years, Gotlieb and Lin used the SARPES detector to thoroughly map out the spin pattern at Lanzara’s lab. When they needed higher photon energies to excite a wider range of electrons within a sample, the researchers moved the detector next door to Berkeley Lab’s synchrotron, the Advanced Light Source (ALS), a U.S. DOE Office of Science User Facility that specializes in lower energy, “soft” X-ray light for studying the properties of materials.

    LBNL/ALS

    The SARPES detector was developed by Lanzara, along with co-authors Zahid Hussain, the former ALS Division Deputy, and Chris Jozwiak, an ALS staff scientist. The detector allowed the scientists to probe key electronic properties of the electrons such as valence band structure.

    After tens of experiments at the ALS, where the team of researchers connected the SARPES detector to Beamline 10.0.1 so they could access this powerful light to explore the spin of the electrons moving with much higher momentum through the superconductor than those they could access in the lab, they found that Bi-2212’s distinct spin pattern – called “nonzero spin – was a true result, inspiring them to ask even more questions. “There remains many unsolved questions in the field of high-temperature superconductivity,” said Lin. “Our work provides new knowledge to better understand the cuprate superconductors, which can be a building block to resolve these questions.”

    Lanzara added that their discovery couldn’t have happened without the collaborative “team science” of Berkeley Lab, a DOE national lab with historic ties to nearby UC Berkeley. “This work is a typical example of where science can go when people with expertise across the scientific disciplines come together, and how new instrumentation can push the boundaries of science,” she said.

    Co-authors with Gotlieb, Lin, and Lanzara are Maksym Serbyn of the Institute of Science and Technology Austria, Wentao Zhang of Shanghai Jiao Tong University, Christopher L. Smallwood of San Jose State University, Christopher Jozwiak of Berkeley Lab, Hiroshi Eisaki of the National Institute of Advanced Industrial Science and Technology of Japan, Zahid Hussain of Berkeley Lab, and Ashvin Vishwanath, formerly of UC Berkeley and now with Harvard University and a Faculty Scientist in Berkeley Lab’s Materials Sciences Division.

    The work was supported by the DOE Office of Science.

    See the full article here .

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    Bringing Science Solutions to the World

    In the world of science, Lawrence Berkeley National Laboratory (Berkeley Lab) is synonymous with “excellence.” Thirteen Nobel prizes are associated with Berkeley Lab. Seventy Lab scientists are members of the National Academy of Sciences (NAS), one of the highest honors for a scientist in the United States. Thirteen of our scientists have won the National Medal of Science, our nation’s highest award for lifetime achievement in fields of scientific research. Eighteen of our engineers have been elected to the National Academy of Engineering, and three of our scientists have been elected into the Institute of Medicine. In addition, Berkeley Lab has trained thousands of university science and engineering students who are advancing technological innovations across the nation and around the world.

    Berkeley Lab is a member of the national laboratory system supported by the U.S. Department of Energy through its Office of Science. It is managed by the University of California (UC) and is charged with conducting unclassified research across a wide range of scientific disciplines. Located on a 202-acre site in the hills above the UC Berkeley campus that offers spectacular views of the San Francisco Bay, Berkeley Lab employs approximately 3,232 scientists, engineers and support staff. The Lab’s total costs for FY 2014 were $785 million. A recent study estimates the Laboratory’s overall economic impact through direct, indirect and induced spending on the nine counties that make up the San Francisco Bay Area to be nearly $700 million annually. The Lab was also responsible for creating 5,600 jobs locally and 12,000 nationally. The overall economic impact on the national economy is estimated at $1.6 billion a year. Technologies developed at Berkeley Lab have generated billions of dollars in revenues, and thousands of jobs. Savings as a result of Berkeley Lab developments in lighting and windows, and other energy-efficient technologies, have also been in the billions of dollars.

    Berkeley Lab was founded in 1931 by Ernest Orlando Lawrence, a UC Berkeley physicist who won the 1939 Nobel Prize in physics for his invention of the cyclotron, a circular particle accelerator that opened the door to high-energy physics. It was Lawrence’s belief that scientific research is best done through teams of individuals with different fields of expertise, working together. His teamwork concept is a Berkeley Lab legacy that continues today.

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

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  • richardmitnick 7:47 pm on August 18, 2016 Permalink | Reply
    Tags: ALS, , ,   

    From Brown: “Study shows how mutations disrupt ALS-linked protein” 

    Brown University
    Brown University

    August 18, 2016
    David Orenstein
    david_orenstein@brown.edu
    401-863-1862

    1
    Concentrate not aggregate. New research explains how the protein TDP43 normally concentrates into droplets and how ALS-related mutations disrupt that, leading to them to form more problematic aggregates that afflict cells. Gül Zerze, Lehigh University

    In amyotrophic lateral sclerosis, aggregates of the protein TDP-43 are almost always found in afflicted neurons and glial cells. Meanwhile, about 50 ALS-linked mutations are known to affect a particular region of TDP-43. Yet scientists have never understood how those two associations connect. A new study in the journal Structure shows how ALS mutations disrupt the protein at the atomic level, preventing it from executing its proper function and instead leading to those aggregates.

    “We knew that part of TDP-43 builds up in aggregates and that there are 50 mutations in that domain, but we didn’t know the job of that domain, how it goes wrong and why it aggregates,” said study corresponding author Nicolas Fawzi, assistant professor in the Department of Molecular Pharmacology, Physiology and Biotechnology at Brown University.

    In general, TDP-43 acts like a chaperone for RNA in a cell, binding to it, guiding its processing, transporting it to where it needs to go and regulating it, so that other proteins can be expressed properly. Using nuclear magnetic resonance, computer simulations and microscopy, Fawzi, Brown graduate student Alexander Conicella and colleagues at Lehigh University were able to show that under normal circumstances, TDP-43 molecules concentrate into little droplets, a process called “liquid-liquid phase separation.” It’s within these droplets that they could process and ferry RNA.

    The team’s focus was on a particular region of TDP-43, called the “C-terminal domain,” which appeared to be crucial in the concentration of molecules that leads to phase separation.

    “We were looking for a functional role for this part of the protein,” Fawzi said “Its job can’t just be to do nothing and then aggregate in disease.”

    The observations showed that the interactions and resulting concentration of TDP-43 molecules depend on a small corkscrew-shaped part of the protein’s C-terminal domain termed a helix. The same sequence of DNA specifying that corkscrew shape has been exactly preserved by evolution in many vertebrate animals suggesting it has an important biological function.

    What Fawzi and his teams observed is that as one TDP-43 molecule meets another, the corkscrews stabilize and lengthen, promoting a bond between them.

    Finally, the team shows in the paper that the various ALS mutations disrupt this process, either by upsetting the formation of the corkscrews or their ability to lengthen and stabilize.

    “Mutations in this [corkscrew] region blow that interaction up,” Fawzi said.

    The result is that the concentration and phase separation does not occur. Instead the proteins can combine in a more potentially harmful way — in the aggregates seen in diseased neurons.

    By ferreting out this mechanistic connection between the mutations, the loss of protein’s proper phase separation behavior and how it frees molecules up to aggregate, the team shows how the mutations could lead to disease, Fawzi said.

    “That might be one mechanism by which ALS mutation cause ALS — by disrupting TDP-43’s normal function,” he said.

    The paper further emphasizes the urgency of an overarching question in ALS. Only about 10 percent of ALS cases are traceable to a genetic cause. It remains unclear what’s happening to disrupt TDP-43 in many cases when a known mutation is not the cause.

    But now scientists have new a new set of data and an explanation of how TDP-43 appears to work and what can make it fail.

    That’s also important, Fawzi noted, because TDP-43 is implicated in other degenerative neural diseases as well.

    “Given the recent evidence that TDP-43 also accumulates in Alzheimer’s disease, understanding the role of TDP-43 is all the more urgent,” he said.

    In addition to Fawzi and Conicella, the paper’s other authors are Gul Zerze and Jeetain Mittal of Lehigh.

    The U.S. National Institutes of Health and Department of Energy supported the research which occurred, in part, at the the Leduc Bioimaging Facility and Structural Biology Core Facility at Brown.

    See the full article here .

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    Welcome to Brown

    Brown U Robinson Hall
    Located in historic Providence, Rhode Island and founded in 1764, Brown University is the seventh-oldest college in the United States. Brown is an independent, coeducational Ivy League institution comprising undergraduate and graduate programs, plus the Alpert Medical School, School of Public Health, School of Engineering, and the School of Professional Studies.

    With its talented and motivated student body and accomplished faculty, Brown is a leading research university that maintains a particular commitment to exceptional undergraduate instruction.

    Brown’s vibrant, diverse community consists of 6,000 undergraduates, 2,000 graduate students, 400 medical school students, more than 5,000 summer, visiting and online students, and nearly 700 faculty members. Brown students come from all 50 states and more than 100 countries.

    Undergraduates pursue bachelor’s degrees in more than 70 concentrations, ranging from Egyptology to cognitive neuroscience. Anything’s possible at Brown—the university’s commitment to undergraduate freedom means students must take responsibility as architects of their courses of study.

     
  • richardmitnick 7:27 am on June 21, 2016 Permalink | Reply
    Tags: ALS, , RUCDR Infinite Biologics, , Target ALS Foundation   

    From Rutgers: “Target ALS Foundation Selects RUCDR Infinite Biologics” 

    Rutgers University
    Rutgers University

    6/20/16
    No writer credit found

    The Target ALS Foundation has selected RUCDR Infinite Biologics to bank and distribute the foundation’s human stem cell lines for use by researchers in academia and industry worldwide.

    A unit of Rutgers’ Human Genetics Institute of New Jersey, RUCDR is the world’s largest university-based biorepository. Target ALS Foundation is a privately funded non-profit foundation “entirely focused on finding treatments for patients living with ALS” or amyotrophic lateral sclerosis, a fatal neurodegenerative disease known as Lou Gehrig’s disease.

    Manish Raisinghani, M.B.B.S., Ph.D., president of Target ALS Foundation, says his organization accelerates ALS drug development by funding consortia-based collaborative projects that require direct involvement of industry as well as by expansion and creation of shared core facilities that lower barriers for academia and industry to pursue ALS drug development.

    “This is the first initiative of its kind to assist ALS researchers in academia and industry by providing stem cells lines for their use while permitting them to retain the data and intellectual property generated by their work,” Raisinghani said.

    More than 50 academic researchers and two dozen companies are using the foundation’s stem cells to date and that number should increase significantly with the additional capabilities and capacity provided by RUCDR. Target ALS currently has 10 stem cells lines in its repository with additional lines in its pipeline.

    “By providing a reliable resource for high quality stem cell lines from Target ALS subjects, we anticipate that our collaboration will encourage scientists around the world to both utilize the existing cell lines as well as contribute new lines to this important collection,” said Michael Sheldon, director of the RUCDR Stem Cell Center.

    The services RUCDR will offer on behalf of Target ALS will be expanding to include genetically modified stem cell lines. The National Institute of Neurological Disorders and Stroke (NINDS) Human Cell and Data Repository (NHCDR), operated under a grant awarded to RUCDR, has added the Target ALS stem cell bank to its widely used online catalog.

    See the full article here .

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    Rutgers, The State University of New Jersey, is a leading national research university and the state’s preeminent, comprehensive public institution of higher education. Rutgers is dedicated to teaching that meets the highest standards of excellence; to conducting research that breaks new ground; and to providing services, solutions, and clinical care that help individuals and the local, national, and global communities where they live.

    Founded in 1766, Rutgers teaches across the full educational spectrum: preschool to precollege; undergraduate to graduate; postdoctoral fellowships to residencies; and continuing education for professional and personal advancement.
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