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  • richardmitnick 5:31 pm on February 10, 2021 Permalink | Reply
    Tags: "HL-LHC Accelerator Upgrade Project receives approval to move full-speed-ahead from Department of Energy", , , , Components will be installed in the HL-LHC from 2025 to early 2027., Critical Decision 3 [CD-3] is the endorsement by DOE to proceed with the full production of the U.S. contribution to the high-luminosity upgrade of the Large Hadron Collider at CERN (CH)., , Fermilab Brookhaven National Laboratory and Lawrence Berkeley National Laboratory are currently building the components and plan to begin delivering the first magnet cryoassembly by late 2021., Fermilab leads the U.S. upgrade effort which comprises two cutting-edge technologies: accelerator magnets and cavities., , , Lawrence Berkeley National Laboratory, , , , , , , The 16 FNAL magnets will be installed in eight cryoassemblies., The AUP accelerator cavities made of niobium are a type known as “crab cavities”., The HL-LHC Accelerator Upgrade Project magnets use conductors made of niobium-tin to generate a stronger magnetic field compared to predecessor technology., The HL-LHC AUP magnets and cavities will be positioned near two of the LHC’s collision points — the ATLAS and CMS particle detectors., The HL-LHC is expected to start operations in 2027 and run through the 2030s., The increase in the number of collisions could also uncover rare physics phenomena or signs of new physics.,   

    From DOE’s Fermi National Accelerator Laboratory: “HL-LHC Accelerator Upgrade Project receives approval to move full-speed-ahead from Department of Energy” 

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

    From DOE’s Fermi National Accelerator Laboratory , an enduring source of strength for the US contribution to scientific research world wide.

    February 10, 2021
    Leah Hesla

    The U.S. Department of Energy has formally approved the start of execution of the High-Luminosity LHC Accelerator Upgrade Project being carried out at eight U.S. institutions.

    The approval, known as Critical Decision 3, or CD-3, is the endorsement by DOE to proceed with the full production of the U.S. contribution to the high-luminosity upgrade of the Large Hadron Collider, or HL-LHC, at the European laboratory CERN.

    Fermilab leads the U.S. upgrade effort, which comprises two cutting-edge technologies: accelerator magnets and cavities. Under the HL-LHC Accelerator Upgrade Project, or AUP, the U.S. collaborators will contribute 16 magnets to dramatically focus the LHC’s near-light-speed particle beams to a tiny volume before colliding. The collaborators are also contributing eight superconducting cavities, radio-frequency devices designed to manipulate the powerful beams. (They will also provide four spare magnets and two spare cavities.)

    With CD-3 approval, AUP collaborators can now move full-speed-ahead building and delivering the crucial components. The new instruments will enable a giant leap in the number of particle collisions at the future HL-LHC, a 10-fold increase compared to the current LHC.

    The high-luminosity upgrade to the Large Hadron Collider will enable physicists to study particles such as the Higgs boson in greater detail. And the increase in the number of collisions could also uncover rare physics phenomena or signs of new physics.

    1
    The HL-LHC Accelerator Upgrade Project magnets use conductors made of niobium-tin to generate a stronger magnetic field compared to predecessor technology. These world-record-setting magnets will have their debut in the HL-LHC: Its run will be the first time that U.S.-built niobium-tin magnets will be used in a particle accelerator for particle physics research. Credit: Dan Cheng/LBNL.

    Gaining DOE’s endorsement to move to full production is a huge achievement. Knowing what it means for the future of particle physics — for the new physics that the HL-LHC will reveal and for future accelerators enabled by these technologies — makes it even more gratifying,” said Giorgio Apollinari, Fermilab scientist and HL-LHC AUP project manager. “I congratulate the entire AUP team on the milestone. They have been instrumental in ensuring the development and technical successes of the leading-edge technologies needed for the HL-LHC.”

    The AUP is supported by the DOE Office of Science. The AUP team consists of six U.S. laboratories and two universities: Fermilab, Brookhaven National Laboratory, Lawrence Berkeley National Laboratory, SLAC National Accelerator Laboratory, Thomas Jefferson National Accelerator Facility (all DOE national laboratories), the National High Magnetic Field Laboratory, Old Dominion University and the University of Florida.

    The AUP magnets use conductors made of niobium-tin to generate a stronger magnetic field compared to predecessor technology. These world-record-setting magnets will have their debut in the HL-LHC: Its run will be the first time that U.S.-built niobium-tin magnets will be used in a particle accelerator for particle physics research.

    The 16 magnets will be installed in eight cryoassemblies — cooling and housing units that enable the magnets’ superconductivity.

    “It is very exciting to see this cutting-edge magnet technology, which is enabling breakthrough science at the LHC, enter the production phase after the successful tests of our first magnets and with the approval of CD-3,” said scientist Kathleen Amm, the Brookhaven representative for the Accelerator Upgrade Project and director of Brookhaven’s Magnet Division. “The incredible talent across our national laboratories working seamlessly has made this possible.”

    2
    The operation of crab cavities like this one in the High-Luminosity LHC will be the first application of Fermilab superconducting radio-frequency technology — building upon critical contributions from Jefferson Lab, Old Dominion University, SLAC and industrial partners — in a particle-physics-dedicated accelerator. Credit: Ryan Postel/Fermilab.

    The AUP accelerator cavities, made of niobium, are a type known as “crab cavities,” manipulating the beam in a particular way to increase the likelihood of particle collisions. While Fermilab high-performance superconducting cavities have already been put to good use in accelerators such as XFEL in Germany or LCLS-II at SLAC National Accelerator Laboratory, the operation of these crab cavities in the HL-LHC will be the first application of Fermilab superconducting radio-frequency technology — building upon critical contributions from Jefferson Lab, Old Dominion University, SLAC and industrial partners — in a particle-physics-dedicated accelerator.

    At the Large Hadron Collider, beams of protons race in opposite directions around the collider’s 17-mile circumference, colliding at high energies at four specific interaction points along the way. Scientists study the collisions to better understand nature’s constituent components and to look for exotic states of matter, such as dark matter.

    The HL-LHC AUP magnets and cavities will be positioned near two of the LHC’s collision points — the ATLAS and CMS particle detectors. These giant, stories-high instruments are also being upgraded to take full advantage of the HL-LHC’s more rapid-fire collisions.

    Over the course of the HL-LHC Accelerator Upgrade Project, the AUP team has seen one success after another, hitting both technological and project milestones according to the schedule established in 2015, says Apollinari. The U.S. collaboration’s first focusing magnet, completed last year, met or exceeded specifications.

    “Building such an ambitious machine requires not only vision but discipline in carrying it out — tight, transparent, respectful coordination with partners, including with funding agencies and the independent reviewers,” Apollinari said. “The achievement is not only that we received CD-3 approval, but how we got here. We met our goals on a timescale that was put down on paper five years ago. That’s thanks to incredible teamwork of everyone involved.”

    Fermilab, Brookhaven National Laboratory and Lawrence Berkeley National Laboratory are currently building the components and plan to begin delivering the first magnet cryoassembly by late 2021 for critical tests. Components will be installed in the HL-LHC from 2025 to early 2027. The HL-LHC is expected to start operations in 2027 and run through the 2030s.

    “HL-LHC is a truly global scientific and engineering undertaking that will usher in a new era of research and discovery in particle physics. AUP plays a critical role in making this possible,” said Fermilab Director Nigel Lockyer. “The technologies developed by AUP will be important not only for the operation of HL-LHC, but also for the viability of future hadron colliders and the future of the field of particles — beyond the end of the HL-LHC’s run.”

    Learn more about the LHC Accelerator Upgrade project, the AUP focusing magnets and the AUP cavities.

    See the full here.


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    Please help promote STEM in your local schools.

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    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 10:34 am on October 8, 2020 Permalink | Reply
    Tags: "An Electrical Trigger Fires Single Identical Photons", , Defining single-photon light sources in two-dimensional materials with atomic precision provides unprecedented insight critical to understanding how those sources work ., Lawrence Berkeley National Laboratory, , , , , Semiconductor nanoparticles or “quantum dots”, This work provides a strategy for making groups of perfectly identical ones.   

    From Lawrence Berkeley National Laboratory: “An Electrical Trigger Fires Single Identical Photons” 


    From Lawrence Berkeley National Laboratory

    October 8, 2020
    Rachel Berkowitz

    1
    Illustration of a gold-covered probe tip injecting electrons into a carefully located imperfection in an atomically thin material. The energy from each electron causes the highly localized emission of a single photon, which may then be guided to a detector. Credit: Ignacio Gaubert.

    Secure telecommunications networks and rapid information processing make much of modern life possible. To provide more secure, faster, and higher-performance information sharing than is currently possible, scientists and engineers are designing next-generation devices that harness the rules of quantum physics. Those designs rely on single photons to encode and transmit information across quantum networks and between quantum chips. However, tools for generating single photons do not yet offer the precision and stability required for quantum information technology.

    Now, as reported recently in the journal Science Advances, researchers have found a way to generate single, identical photons on demand. By positioning a metallic probe over a designated point in a common 2D semiconductor material, the team led by researchers at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) has triggered a photon emission electrically. The photon’s properties may be simply adjusted by changing the applied voltage.

    “The demonstration of electrically driven single-photon emission at a precise point constitutes a big step in the quest for integrable quantum technologies,” said Alex Weber-Bargioni, a staff scientist at Berkeley Lab’s Molecular Foundry who led the project. The research is part of the Center for Novel Pathways to Quantum Coherence in Materials (NPQC), an Energy Frontier Research Center sponsored by the Department of Energy, whose overarching goal is to find new approaches to protect and control quantum memory that can provide new insights into novel materials and designs for quantum computing technology.

    Photons are one of the most robust carriers of quantum information and can travel long distances without losing their memory, or so-called coherence. To date, most established schemes for secure communication transfer that will power large-scale quantum communications require light sources to generate one photon at a time. Each photon must have a precisely defined wavelength and orientation. The new photon emitter demonstrated at Berkeley Lab achieves that control and precision. It could be used for transferring information between quantum processors on different chips, and ultimately scaled up to larger processors and a future quantum internet that links sophisticated computers around the world.

    The photon emitter is based on a common 2D semiconductor material (tungsten disulfide, WS2), which has a sulfur atom removed from its crystal structure. That carefully located atomic imperfection, or defect, serves as a point where the photon can be generated through application of an electric current.

    2
    A map shows the intensity and locations of photons emitted from a thin-film material while a voltage is applied. Credit: Berkeley Lab.

    The challenge is not how to generate single photons, but how to make them truly identical and produce them on demand. Photon-emitting devices, like the semiconductor nanoparticles or “quantum dots” that light up QLED TVs, that are fabricated by lithography are subject to inherent variability, since no pattern-based system can be identical down to a single atom. Researchers working with Weber-Bargioni took a different approach by growing a thin-film material on a sheet of graphene. Any impurities introduced to the thin film’s atomic structure are repeated and identical throughout the sample. Through simulations and experiments, the team determined just where to introduce an imperfection to the otherwise uniform structure. Then, by applying an electrical contact to that location, they were able to trigger the material to emit a photon and control its energy with the applied voltage. That photon is then available to carry information to a distant location.

    “Single-photon emitters are like a terminal where carefully prepared but fragile quantum information is sent on a journey into a lightning-fast, sturdy box,” said Bruno Schuler, a postdoctoral researcher at the Molecular Foundry (now a research scientist at Empa – the Swiss Federal Laboratories for Materials Science and Technology) and lead author of the work.

    Key to the experiment is the gold-coated tip of a scanning tunnelling microscope that can be positioned exactly over the defect site in the thin-film material. When a voltage is applied between the probe tip and the sample, the tip injects an electron into the defect. When the electron travels or tunnels from the probe tip, a well-defined part of its energy gets transformed into a single photon. Finally, the probe tip acts as an antenna that helps guide the emitted photon to an optical detector which records its wavelength and position.

    By mapping the photons emitted from thin films made to include various defects, the researchers were able to pinpoint the correlation between the injected electron, local atomic structure, and the emitted photon. Usually, the optical resolution of such a map is limited to a few hundred nanometers. Thanks to extremely localized electron injection, combined with state-of-the-art microscopy tools, the Berkeley Lab team could determine where in the material a photon emerged with a resolution below 1 angstrom, about the diameter of a single atom. The detailed photon maps were crucial to pinpointing and understanding the electron-triggered photon emission mechanism.

    “In terms of technique, this work has been a great breakthrough because we can map light emission from a single defect with sub-nanometer resolution. We visualize light emission with atomic resolution,” said Katherine Cochrane, a postdoctoral researcher at the Molecular Foundry and a lead author on the paper.

    Defining single-photon light sources in two-dimensional materials with atomic precision provides unprecedented insight critical to understanding how those sources work, and provides a strategy for making groups of perfectly identical ones. The work is part of NPQC’s focus on exploring novel quantum phenomena in nonhomogenous 2D materials.

    Two-dimensional materials are leading the way as a powerful platform for next-generation photon emitters. The thin films are flexible and easily integrated with other structures, and now provide a systematic way for introducing unparalleled control over photon emission. Based on the new results, the researchers plan to work on employing new materials to use as photon sources in quantum networks and quantum simulations.

    This research was supported by the DOE Office of Science and grants from the Swiss National Science Foundation.

    The Molecular Foundry is a DOE Office of Science user facility located at Berkeley Lab.

    See the full article here .

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    LBNL campus

    LBNL Molecular Foundry

    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.

    University of California Seal

     
  • richardmitnick 10:16 am on October 8, 2020 Permalink | Reply
    Tags: "New Algorithm Sharpens Focus of World’s Most Powerful Microscopes", , , Lawrence Berkeley National Laboratory,   

    From Lawrence Berkeley National Laboratory: “New Algorithm Sharpens Focus of World’s Most Powerful Microscopes” 


    From Lawrence Berkeley National Laboratory

    October 8, 2020
    Aliyah Kovner
    akovner@lbl.gov

    1
    A composite image of the enzyme lactase showing how cryo-EM’s resolution has improved dramatically in recent years. Older images to the left, more recent to the right. (Credit: Veronica Falconieri/National Cancer Institute)

    We’ve all seen that moment in a cop TV show where a detective is reviewing grainy, low-resolution security footage, spots a person of interest on the tape, and nonchalantly asks a CSI technician to “enhance that.” A few keyboard clicks later, and voila – they’ve got a perfect, clear picture of the suspect’s face. This, of course, does not work in the real world, as many film critics and people on the internet like to point out.

    However, real-life scientists have recently developed a true “enhance” tool: one that improves the resolution and accuracy of powerful microscopes that are used to reveal insights into biology and medicine.

    In a study published in Nature Methods, a multi-institutional team led by Tom Terwilliger from the New Mexico Consortium and including researchers from Lawrence Berkeley National Laboratory (Berkeley Lab) demonstrates how a new computer algorithm improves the quality of the 3D molecular structure maps generated with cryo-electron microscopy (cryo-EM).

    For decades, these cryo-EM maps – generated by taking many microscopy images and applying image-processing software – have been a crucial tool for researchers seeking to learn how the molecules within animals, plants, microbes, and viruses function. And in recent years, cryo-EM technology has advanced to the point that it can produce structures with atomic-level resolution for many types of molecules. Yet in some situations, even the most sophisticated cryo-EM methods still generate maps with lower resolution and greater uncertainty than required to tease out the details of complex chemical reactions.

    “In biology, we gain so much by knowing a molecule’s structure,” said study co-author Paul Adams, Director of the Molecular Biophysics & Integrated Bioimaging Division at Berkeley Lab. “The improvements we see with this algorithm will make it easier for researchers to determine atomistic structural models from electron cryo-microscopy data. This is particularly consequential for modeling very important biological molecules, such as those involved in transcribing and translating the genetic code, which are often only seen in lower-resolution maps due to their large and complex multi-unit structures.”

    The algorithm sharpens molecular maps by filtering the data based on existing knowledge of what molecules look like and how to best estimate and remove noise (unwanted and irrelevant data) in microscopy data. An approach with the same theoretical basis was previously used to improve structure maps generated from X-ray crystallography, and scientists have proposed its use in cryo-EM before. But, according to Adams, no one had been able to show definitive evidence that it worked for cryo-EM until now.

    The team – composed of scientists from New Mexico Consortium, Los Alamos National Laboratory, Baylor College of Medicine, Cambridge University, and Berkeley Lab – first applied the algorithm to a publicly available map of the human protein apoferritin that is known to have 3.1-angstrom resolution (an angstrom is equal to a 10-billionth of a meter; for reference, the diameter of a carbon atom is estimated to be 2 angstroms). Then, they compared their enhanced version to another publicly available apoferritin reference map with 1.8-angstrom resolution, and found improved correlation between the two.

    Next, the team used their approach on 104 map datasets from the Electron Microscopy Data Bank. For a large proportion of these map sets, the algorithm improved the correlation between the experimental map and the known atomic structure, and increased the visibility of details.

    2
    Using the enzyme β-galactosidase, also called lactase, as a test case, the researchers applied the standard methods (a) and then applied the improvement algorithm without (b) and with a filter to improve the uniformity of noise in the map (c), both of these maps are more similar to the deposited high-resolution protein structure map (d). (Credit: Terwilliger et al./Nature Methods)

    The authors note that the clear benefits of the algorithm in revealing important details in the data, combined with its ease of use – it is an automated analysis that can be performed on a laptop processor – will likely make it part of a standard part of the cryo-EM workflow moving forward. In fact, Adams has already added the algorithm’s source code to the Phenix software suite, a popular package for automated macromolecular structure solution for which he leads the development team.

    This research was part of Berkeley Lab’s continued efforts to advance the capabilities of cryo-EM technology and to pioneer its use for basic science discoveries. Many of the breakthrough inventions that enabled the development of cryo-EM and later pushed it to its exceptional current resolution have involved Berkeley Lab scientists.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    LBNL campus

    LBNL Molecular Foundry

    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.

    University of California Seal

     
  • richardmitnick 10:15 am on October 7, 2020 Permalink | Reply
    Tags: "Jennifer Doudna Wins 2020 Nobel Prize in Chemistry", , Lawrence Berkeley National Laboratory,   

    From UC Berkeley and Lawrence Berkeley National Laboratory: “Jennifer Doudna Wins 2020 Nobel Prize in Chemistry” 

    From UC Berkeley

    and


    From Lawrence Berkeley National Laboratory

    October 7, 2020
    Theresa Duque
    media@lbl.gov

    1
    Jennifer Doudna (Credit: UC Berkeley)

    Biochemist Jennifer Doudna, a professor at UC Berkeley and faculty scientist at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), is co-winner of the 2020 Nobel Prize in Chemistry for “the development of a method for genome editing.” [She now gets her own parking spot in the parking lot reserved for Nobel Prize winners.]

    UC Berkeley parking lot for Nobel Prize winners.

    2
    The bacterial enzyme Cas9 is the engine of RNA-programmed genome engineering in human cells. Credit: Graphic by Jennifer Doudna/UC Berkeley.


    UC Berkeley 2020 Nobel Press Conference

    She shares the Nobel Prize with co-discoverer Emmanuelle Charpentier, who currently serves as the scientific and managing director of the Max Planck Unit for the Science of Pathogens in Berlin. Together, they form the first all-woman research team to win a Nobel Prize.

    “On behalf of the Berkeley Lab community, I extend my warmest congratulations to Jennifer Doudna for receiving the Nobel Prize in Chemistry. She is an exceptional scientist, and her groundbreaking research will inspire the next generation of scientists to take on challenges that both push the boundaries of knowledge and benefit humanity,” said Berkeley Lab Director Mike Witherell.

    The discovery of the CRISPR-Cas9 genetic engineering technology has radically changed genomics research. This genome-editing technology enables scientists to change or remove genes quickly, with a precision only dreamed of just a few years ago. Labs worldwide have redirected the course of their research to incorporate this new tool, with huge implications across biology, agriculture, and medicine.

    Doudna is a faculty scientist in Berkeley Lab’s Molecular Biophysics and Integrated Bioimaging Division; a professor of molecular and cell biology, and chemistry, at UC Berkeley; and an investigator at the Howard Hughes Medical Institute.

    Foundational Berkeley Lab research

    Doudna’s interest in gene editing can be traced to her research as a doctoral student at Harvard Medical School, when she designed a self-replicating RNA. As a research fellow at the University of Colorado at Boulder, she began crystallizing RNA so that she could study its structure and understand the physical basis of catalysis. While on the faculty at Yale University, she continued her study of catalytic RNA. When she joined UC Berkeley and Berkeley Lab in 2002, she pursued her interest in how RNA molecules decide what genetic information gets disseminated in cells.

    In 2008, Doudna’s nascent research on CRISPR RNA strands and the Cas1 protein was funded by a U.S. Department of Energy (DOE) Laboratory Directed Research and Development (LDRD) Program through her Berkeley Lab affiliation. Established by Congress in 1991, the LDRD program has helped the U.S. remain at the forefront of technology through the innovative, multidisciplinary research of the DOE national labs.

    Building upon findings from this early work and other investigations, in 2012, Doudna and Charpentier’s research team detailed the underlying mechanisms of the CRISPR-Cas9 system – a component of the bacterial immune system that defends against invading viruses – and explained how it can be programmed to cut DNA at a target sequence. This seminal work was published in the journal Science.

    Today, Doudna and Charpentier’s Nobel Prize-winning CRISPR-Cas9 technology is the basis of many promising medical technologies, including tools to diagnose and treat disease, and has many applications for the development of improved crops, biofuels, and bioproducts.

    With Doudna’s award, Berkeley Lab scientists and research have now been recognized with 14 Nobel Prizes.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    LBNL campus

    LBNL Molecular Foundry

    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.

    University of California Seal

    Founded in the wake of the gold rush by leaders of the newly established 31st state, the University of California’s flagship campus at Berkeley has become one of the preeminent universities in the world. Its early guiding lights, charged with providing education (both “practical” and “classical”) for the state’s people, gradually established a distinguished faculty (with 22 Nobel laureates to date), a stellar research library, and more than 350 academic programs.

    UC Berkeley Seal

     
  • richardmitnick 10:28 am on September 30, 2020 Permalink | Reply
    Tags: "Scientists Capture Candid Snapshots of Electrons Harvesting Light at the Atomic Scale", , , Lawrence Berkeley National Laboratory, , The electrons’ role in the harvesting of light for solar fuels., TRXPS-picosecond time-resolved X-ray photoelectron spectroscopy   

    From Lawrence Berkeley National Laboratory: “Scientists Capture Candid Snapshots of Electrons Harvesting Light at the Atomic Scale” 


    September 30, 2020
    Theresa Duque
    tnduque@lbl.gov
    (510) 424-2866

    1
    A research team led by Berkeley Lab has gained important new insight into electrons’ role in the harvesting of light for solar fuels. (Credit: Surat Sangwato/Shutterstock)

    A research team led by Berkeley Lab has gained important new insight into electrons’ role in the harvesting of light for solar fuels. (Credit: Surat Sangwato/Shutterstock)

    In the search for clean energy alternatives to fossil fuels, one promising solution relies on photoelectrochemical (PEC) cells – water-splitting, artificial-photosynthesis devices that turn sunlight and water into solar fuels such as hydrogen.

    In just a decade, researchers in the field have achieved great progress in the development of PEC systems made of light-absorbing gold nanoparticles – tiny spheres just billionths of a meter in diameter – attached to a semiconductor film of titanium dioxide nanoparticles (TiO2 NP). But despite these advancements, researchers still struggle to make a device that can produce solar fuels on a commercial scale.

    Now, a team of scientists led by the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) has gained important new insight into electrons’ role in the harvesting of light in gold/TiO2 NP PEC systems. The scientists say that their study, recently published in the Journal of Physical Chemistry Letters, can help researchers develop more efficient material combinations for the design of high-performance solar fuels devices.

    “By quantifying how electrons do their work on the nanoscale and in real time, our study can help to explain why some water-splitting PEC devices did not work as well as hoped,” said senior author Oliver Gessner, a senior scientist in Berkeley Lab’s Chemical Sciences Division.

    And by tracing the movement of electrons in these complex systems with chemical specificity and picosecond (trillionths of a second) time resolution, the research team members believe they have developed a new tool that can more accurately calculate the solar fuels conversion efficiency of future devices.

    Electron-hole pairs: A productive pairing comes to light

    Researchers studying water-splitting PEC systems have been interested in gold nanoparticles’ superior light absorption due to their “plasmonic resonance” – the ability of electrons in gold nanoparticles to move in sync with the electric field of sunlight.

    “The trick is to transfer electrons between two different types of materials – from the light-absorbing gold nanoparticles to the titanium-dioxide semiconductor,” Gessner explained.

    2
    Illustration of a PEC model system with 20-nanometer gold nanoparticles attached to titanium dioxide.Credit: Berkeley Lab.

    When electrons are transferred from the gold nanoparticles into the titanium dioxide semiconductor, they leave behind “holes.” The combination of an electron injected into titanium dioxide and the hole the electron left behind is called an electron-hole pair. “And we know that electron-hole pairs are critical ingredients to enabling the chemical reaction for the production of solar fuels,” he added.

    But if you want to know how well a plasmonic PEC device is working, you need to learn how many electrons moved from the gold nanoparticles to the semiconductor, how many electron-hole pairs are formed, and how long these electron-hole pairs last before the electron returns to a hole in the gold nanoparticle. “The longer the electrons are separated from the holes in the gold nanoparticles – that is, the longer the lifetime of the electron-hole pairs – the more time you have for the chemical reaction for fuels production to take place,” Gessner explained.

    To answer these questions, Gessner and his team used a technique called “picosecond time-resolved X-ray photoelectron spectroscopy (TRXPS)” at Berkeley Lab’s Advanced Light Source (ALS) to count how many electrons transfer between the gold nanoparticles and the titanium-dioxide film, and to measure how long the electrons stay in the other material.

    LBNL ALS .

    Gessner said his team is the first to apply the X-ray technique for studying this transfer of electrons in plasmonic systems such as the nanoparticles and the film. “This information is crucial to develop more efficient material combinations.”

    An electronic ‘count’-down with TRXPS

    Using TRXPS at the ALS, the team shone pulses of laser light to excite electrons in 20-nanometer (20 billionths of a meter) gold nanoparticles (AuNP) attached to a semiconducting film made of nanoporous titanium dioxide (TiO2).

    The team then used short X-ray pulses to measure how many of these electrons “traveled” from the AuNP to the TiO2 to form electron-hole pairs, and then back “home” to the holes in the AuNP.

    “When you want to take a picture of someone moving very fast, you do it with a short flash of light – for our study, we used short flashes of X-ray light,” Gessner said. “And our camera is the photoelectron spectrometer that takes short ‘snapshots’ at a time resolution of 70 picoseconds.”

    The TRXPS measurement revealed a few surprises: They observed two electrons transfer from gold to titanium dioxide – a far smaller number than they had expected based on previous studies. They also learned that only one in 1,000 photons (particles of light) generated an electron-hole pair, and that it takes just a billionth of a second for an electron to recombine with a hole in the gold nanoparticle.

    Altogether, these findings and methods described in the current study could help researchers better estimate the optimal time needed to trigger solar fuels production at the nanoscale.

    “Although X-ray photoelectron spectroscopy is a common technique used at universities and research institutions around the world, the way we expanded it for time-resolved studies and used it here is very unique and can only be done at Berkeley Lab’s Advanced Light Source,” said Monika Blum, a co-author of the study and research scientist at the ALS.

    “Monika’s and Oliver’s unique use of TRXPS made it possible to identify how many electrons on gold are activated to become charge carriers – and to locate and track their movement throughout the surface region of a nanomaterial – with unprecedented chemical specificity and picosecond time resolution,” said co-author Francesca Toma, a staff scientist at the Joint Center for Artificial Photosynthesis (JCAP) in Berkeley Lab’s Chemical Sciences Division. “These findings will be key to gaining a better understanding of how plasmonic materials can advance solar fuels.”

    The team next plans to push their measurements to even faster time scales with a free-electron laser, and to capture even finer nanoscale snapshots of electrons at work in a PEC device when water is added to the mix.

    Co-authors with Berkeley Lab’s Gessner, Blum, and Toma include lead author Mario Borgwardt, Guiji Liu, Johannes Mahl, Friedrich Roth, Lukas Wenthaus, Felix Brauße, and Klaus Schwarsburg.

    Researchers from the Institute of Experimental Physics, TU Bergakademie Freiberg; Deutsches Electronen Synchrotron/DESY; and the Institute for Solar Fuels, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Germany, also contributed to the study.

    This work was supported by the DOE Office of Science.

    The Advanced Light Source is a DOE Office of Science user facility located at Berkeley Lab.

    The Joint Center for Artificial Photosynthesis (JCAP) is a DOE Energy Innovation Hub supported through the Office of Science of the U.S. Department of Energy. The Liquid Sunlight Alliance (LiSA), a solar-fuels Hub led by Caltech in partnership with Berkeley Lab, will continue to build on JCAP’s work to advance solar fuels.

    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 10:17 am on September 25, 2020 Permalink | Reply
    Tags: , Lawrence Berkeley National Laboratory, Machine Learning Takes on Synthetic Biology: Algorithms Can Bioengineer Cells for You",   

    From Lawrence Berkeley National Laboratory- “Machine Learning Takes on Synthetic Biology: Algorithms Can Bioengineer Cells for You” 


    From Lawrence Berkeley National Laboratory

    September 25, 2020
    Julie Chao
    JHChao@lbl.gov
    (510) 486-6491

    Berkeley Lab scientists develop a tool that could drastically speed up the ability to design new biological systems.

    1
    Tijana Radivojevic (left) and Hector Garcia Martin working on mechanical and statistical modeling, data visualizations, and metabolic maps at the Agile BioFoundry last year. (Credit: Thor Swift/Berkeley Lab.)

    If you’ve eaten vegan burgers that taste like meat or used synthetic collagen in your beauty routine – both products that are “grown” in the lab – then you’ve benefited from synthetic biology. It’s a field rife with potential, as it allows scientists to design biological systems to specification, such as engineering a microbe to produce a cancer-fighting agent. Yet conventional methods of bioengineering are slow and laborious, with trial and error being the main approach.

    Now scientists at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) have developed a new tool that adapts machine learning algorithms to the needs of synthetic biology to guide development systematically. The innovation means scientists will not have to spend years developing a meticulous understanding of each part of a cell and what it does in order to manipulate it; instead, with a limited set of training data, the algorithms are able to predict how changes in a cell’s DNA or biochemistry will affect its behavior, then make recommendations for the next engineering cycle along with probabilistic predictions for attaining the desired goal.

    “The possibilities are revolutionary,” said Hector Garcia Martin, a researcher in Berkeley Lab’s Biological Systems and Engineering (BSE) Division who led the research. “Right now, bioengineering is a very slow process. It took 150 person-years to create the anti-malarial drug, artemisinin. If you’re able to create new cells to specification in a couple weeks or months instead of years, you could really revolutionize what you can do with bioengineering.”

    Working with BSE data scientist Tijana Radivojevic and an international group of researchers, the team developed and demonstrated a patent-pending algorithm called the Automated Recommendation Tool (ART), described in a pair of papers recently published in the journal Nature Communications [below]. Machine learning allows computers to make predictions after “learning” from substantial amounts of available “training” data.

    In “ART: A machine learning Automated Recommendation Tool for synthetic biology,” led by Radivojevic, the researchers presented the algorithm, which is tailored to the particularities of the synthetic biology field: small training data sets, the need to quantify uncertainty, and recursive cycles.

    https://www.nature.com/articles/s41467-020-18008-4

    The tool’s capabilities were demonstrated with simulated and historical data from previous metabolic engineering projects, such as improving the production of renewable biofuels.

    In “Combining mechanistic and machine learning models for predictive engineering and optimization of tryptophan metabolism,” the team used ART to guide the metabolic engineering process to increase the production of tryptophan, an amino acid with various uses, by a species of yeast called Saccharomyces cerevisiae, or baker’s yeast.

    https://www.nature.com/articles/s41467-020-17910-1

    The project was led by Jie Zhang and Soren Petersen of the Novo Nordisk Foundation Center for Biosustainability at the Technical University of Denmark, in collaboration with scientists at Berkeley Lab and Teselagen, a San Francisco-based startup company.

    To conduct the experiment, they selected five genes, each controlled by different gene promoters and other mechanisms within the cell and representing, in total, nearly 8,000 potential combinations of biological pathways. The researchers in Denmark then obtained experimental data on 250 of those pathways, representing just 3% of all possible combinations, and that data were used to train the algorithm. In other words, ART learned what output (amino acid production) is associated with what input (gene expression).

    Then, using statistical inference, the tool was able to extrapolate how each of the remaining 7,000-plus combinations would affect tryptophan production. The design it ultimately recommended increased tryptophan production by 106% over the state-of-the-art reference strain and by 17% over the best designs used for training the model.

    “This is a clear demonstration that bioengineering led by machine learning is feasible, and disruptive if scalable. We did it for five genes, but we believe it could be done for the full genome,” said Garcia Martin, who is a member of the Agile BioFoundry and also the Director of the Quantitative Metabolic Modeling team at the Joint BioEnergy Institute (JBEI), a DOE Bioenergy Research Center; both supported a portion of this work. “This is just the beginning. With this, we’ve shown that there’s an alternative way of doing metabolic engineering. Algorithms can automatically perform the routine parts of research while you devote your time to the more creative parts of the scientific endeavor: deciding on the important questions, designing the experiments, and consolidating the obtained knowledge.”

    More data needed

    The researchers say they were surprised by how little data was needed to obtain results. Yet to truly realize synthetic biology’s potential, they say the algorithms will need to be trained with much more data. Garcia Martin describes synthetic biology as being only in its infancy – the equivalent of where the Industrial Revolution was in the 1790s. “It’s only by investing in automation and high-throughput technologies that you’ll be able to leverage the data needed to really revolutionize bioengineering,” he said.

    Radivojevic added: “We provided the methodology and a demonstration on a small dataset; potential applications might be revolutionary given access to large amounts of data.”

    The unique capabilities of national labs

    Besides the dearth of experimental data, Garcia Martin says the other limitation is human capital – or machine learning experts. Given the explosion of data in our world today, many fields and companies are competing for a limited number of experts in machine learning and artificial intelligence.

    Garcia Martin notes that knowledge of biology is not an absolute prerequisite, if surrounded by the team environment provided by the national labs. Radivojevic, for example, has a doctorate in applied mathematics and no background in biology. “In two years here, she was able to productively collaborate with our multidisciplinary team of biologists, engineers, and computer scientists and make a difference in the synthetic biology field,” he said. “In the traditional ways of doing metabolic engineering, she would have had to spend five or six years just learning the needed biological knowledge before even starting her own independent experiments.”

    “The national labs provide the environment where specialization and standardization can prosper and combine in the large multidisciplinary teams that are their hallmark,” Garcia Martin said.

    Synthetic biology has the potential to make significant impacts in almost every sector: food, medicine, agriculture, climate, energy, and materials. The global synthetic biology market is currently estimated at around $4 billion and has been forecast to grow to more than $20 billion by 2025, according to various market reports.

    “If we could automate metabolic engineering, we could strive for more audacious goals. We could engineer microbiomes for therapeutic or bioremediation purposes. We could engineer microbiomes in our gut to produce drugs to treat autism, for example, or microbiomes in the environment that convert waste to biofuels,” Garcia Martin said. “The combination of machine learning and CRISPR-based gene editing enables much more efficient convergence to desired specifications.”

    This research is part of the Agile BioFoundry and JBEI, supported by the Department of Energy, and also received support from the Novo Nordisk Foundation and the European Commission. ART is available for licensing on GitHub.

    See the full article here .

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    Please help promote STEM in your local schools.

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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.

    University of California Seal

     
  • richardmitnick 12:15 pm on June 22, 2019 Permalink | Reply
    Tags: A new crystal built of a spiraling stack of atomically thin germanium sulfide sheets., , Lawrence Berkeley National Laboratory, Such “nanosheets” are usually referred to as “2D materials.", the team took advantage of a crystal defect called a screw dislocation a “mistake” in the orderly crystal structure that gives it a bit of a twisting force., These “inorganic” crystals are built of more far-flung eleThese “inorganic” crystals are built of more far-flung elemenmnts of the periodic table — in this case sulfur and germanium, This is Unlike “organic” DNA which is primarily built of familiar atoms like carbon oxygen and hydrogen,   

    From UC Berkeley: “Crystal with a twist: scientists grow spiraling new material” 

    From UC Berkeley

    June 19, 2019
    Kara Manke
    kjmanke@berkeley.edu

    1
    UC Berkeley and Berkeley Lab researchers created a new crystal built of a spiraling stack of atomically thin germanium sulfide sheets. (UC Berkeley image by Yin Liu)

    With a simple twist of the fingers, one can create a beautiful spiral from a deck of cards. In the same way, scientists at the University of California, Berkeley, and Lawrence Berkeley National Laboratory (Berkeley Lab) have created new inorganic crystals made of stacks of atomically thin sheets that unexpectedly spiral like a nanoscale card deck.

    Their surprising structures, reported in a new study appearing online Wednesday, June 20, in the journal Nature, may yield unique optical, electronic and thermal properties, including superconductivity, the researchers say.

    These helical crystals are made of stacked layers of germanium sulfide, a semiconductor material that, like graphene, readily forms sheets that are only a few atoms or even a single atom thick. Such “nanosheets” are usually referred to as “2D materials.”

    “No one expected 2D materials to grow in such a way. It’s like a surprise gift,” said Jie Yao, an assistant professor of materials science and engineering at UC Berkeley. “We believe that it may bring great opportunities for materials research.”

    While the shape of the crystals may resemble that of DNA, whose helical structure is critical to its job of carrying genetic information, their underlying structure is actually quite different. Unlike “organic” DNA, which is primarily built of familiar atoms like carbon, oxygen and hydrogen, these “inorganic” crystals are built of more far-flung elements of the periodic table — in this case, sulfur and germanium. And while organic molecules often take all sorts of zany shapes, due to unique properties of their primary component, carbon, inorganic molecules tend more toward the straight and narrow.

    To create the twisted structures, the team took advantage of a crystal defect called a screw dislocation, a “mistake” in the orderly crystal structure that gives it a bit of a twisting force. This “Eshelby Twist”, named after scientist John D. Eshelby, has been used to create nanowires that spiral like pine trees. But this study is the first time the Eshelby Twist has been used to make crystals built of stacked 2D layers of an atomically thin semiconductor.

    “Usually, people hate defects in a material — they want to have a perfect crystal,” said Yao, who also serves as a faculty scientist at Berkeley Lab. “But it turns out that, this time, we have to thank the defects. They allowed us to create a natural twist between the material layers.”

    In a major discovery [Nature] last year, scientists reported that graphene becomes superconductive when two atomically thin sheets of the material are stacked and twisted at what’s called a “magic angle.” While other researchers have succeeded at stacking two layers at a time, the new paper provides a recipe for synthesizing stacked structures that are hundreds of thousands or even millions of layers thick in a continuously twisting fashion.

    3
    The helical crystals may yield surprising new properties, like superconductivity. (UC Berkeley image by Yin Liu)

    “We observed the formation of discrete steps in the twisted crystal, which transforms the smoothly twisted crystal to circular staircases, a new phenomenon associated with the Eshelby Twist mechanism,” said Yin Liu, co-first author of the paper and a graduate student in materials science and engineering at UC Berkeley. “It’s quite amazing how interplay of materials could result in many different, beautiful geometries.”

    By adjusting the material synthesis conditions and length, the researchers could change the angle between the layers, creating a twisted structure that is tight, like a spring, or loose, like an uncoiled Slinky. And while the research team demonstrated the technique by growing helical crystals of germanium sulfide, it could likely be used to grow layers of other materials that form similar atomically thin layers.

    “The twisted structure arises from a competition between stored energy and the energy cost of slipping two material layers relative to one another,” said Daryl Chrzan, chair of the Department of Materials Science and Engineering and senior theorist on the paper. “There is no reason to expect that this competition is limited to germanium sulfide, and similar structures should be possible in other 2D material systems.”

    “The twisted behavior of these layered materials, typically with only two layers twisted at different angles, has already showed great potential and attracted a lot of attention from the physics and chemistry communities. Now, it becomes highly intriguing to find out, with all of these twisted layers combined in our new material, if will they show quite different material properties than regular stacking of these materials,” Yao said. “But at this moment, we have very limited understanding of what these properties could be, because this form of material is so new. New opportunities are waiting for us.”

    Other co-first authors of the paper include Su Jung Kim and Haoye Sun of UC Berkeley and Jie Wang of Argonne National Laboratory. Other authors include Fuyi Yang, Zixuan Fang, Ruopeng Zhang, Bo Z. Xu, Michael Wang, Shuren Lin, Kyle B. Tom, Yang Deng, Robert O. Ritchie, Andrew M. Minor and Mary C. Scott of UC Berkeley; Nobumichi Tamura, Xiaohui Song, Qin Yu, John Turner and Emory Chan of Berkeley Lab and Jianguo Wen and Dafei Jin of Argonne National Laboratory.

    Work at Berkeley Lab’s Molecular Foundry and the Advanced Light Source was supported by the U.S. Department of Energy’s Office of Science and Office of Basic Energy Sciences under contract no. DE-AC02-05CH11231. The research was also supported by the U.S. Department of Energy’s Office of Science, Office of Basic Energy Sciences and Materials Sciences and Engineering Division under contract no. DE-AC02-244 05CH11231 within the Electronic Materials Program (KC1201).

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    See the full article here .

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    Founded in the wake of the gold rush by leaders of the newly established 31st state, the University of California’s flagship campus at Berkeley has become one of the preeminent universities in the world. Its early guiding lights, charged with providing education (both “practical” and “classical”) for the state’s people, gradually established a distinguished faculty (with 22 Nobel laureates to date), a stellar research library, and more than 350 academic programs.

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