Tag Archives: berkeley lab

Surprising Control over Photoelectrons from a Topological Insulator

By Guest PostMarch 24, 2013Science3d topological insulators, alessandra lanzara, als, angle resolved, arpes, atoms, berkeley lab, chris jozwiak, data collection, dirac point, dung hai lee, electronic states, energy momentum diagrams, field of spintronics, flight analyzer, german, graphene, incident light, laser beam, magnetic surface, momentum space, p polarized, photoelectrons, photoemission spectroscopy, quantum computing, s polarization, s polarized, senkrecht, spin polarized, spin time, steve louie, strange crystalline materials, tis, topological insulator, university of california, zahid hussain

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

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

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

Long Predicted Atomic Collapse State Observed in Graphene

By Guest PostMarch 19, 2013Sciencealex zettl, andrey shytov, artificial atomic nuclei, atomic collapse behavior, atomic collapse state, berkeley lab, calcium dimers, dillon wong, electrical conductor, electronic devices, electronic resonance, electrons, energy, graphene, holy grail, michael crommie, nuclear physics, nucleus, predictions, quantum mechanical phenomenon, relativistic quantum mechanics, roland kawakami, scanning tunneling microscope, smoking gun, Space, stable circular orbits, stm, stm spectroscopy, ultra high vacuum, ultrafast transistors, william regan, yang wang

Berkeley Lab researchers recreate elusive phenomenon with artificial nuclei

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

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

Engineering Bacterial Live Wires

By Guest PostMarch 13, 2013Sciencebacterial species, berkeley lab, bioelectronic systems, biological wire, caroline ajo franklin, cell membranes, cheryl goldbeck, common language, e coli, electron, electronic communication systems, energy, energy conversion techniques, guillaume cambray, heather jensen, information transfer, largus angenent, living cell, matt hepler, metabolic pathways, michaela teravest, molecular foundry, mr 1, mtrcab pathway, nanocrystalline iron oxide, nicole beedle, protein complex, shewanella oneidensis, strain, synthesis, university of california, vivek mutalik, yancey appling

Berkeley Lab scientists discover the balance that allows electricity to flow between cells and electronics

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

Reading the Human Genome

By Guest PostMarch 10, 2013Scienceautomated data collection, berkeley lab, biomolecular machinery, biophysicist eva nogales, cellular process, central dogma, cryo electron microscopy, cryo em, DNA, dna promoter complex, dylan taatjes, gene sequence, genetic information, human genome, jie fang, malfunctions, molecular biology, paula flicker, pre initiation complex, rna, rna polymerase, rna transcription, structural data, tata binding protein, tbp, transcription, transcription factors, yuan he

Berkeley Lab Researchers Produce First Step-by-Step Look at Transcription Initiation

Researchers with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) have achieved a major advance in understanding how genetic information is transcribed from DNA to RNA by providing the first step-by-step look at the biomolecular machinery that reads the human genome.

“We’ve provided a series of snapshots that shows how the genome is read one gene at a time,” says biophysicist Eva Nogales who led this research. “For the genetic code to be transcribed into messenger RNA, the DNA double helix has to be opened and the strand of gene sequences has to be properly positioned so that RNA polymerase, the enzyme that catalyzes transcription, knows where the gene starts. The electron microscopy images we produced show how this is done.” (more…)

New Opportunities for Crystal Growth

By Guest PostMarch 6, 2013Scienceberkeley lab, characterization, crystal growth, crystal growth facility, crystal is unique, crystal purification, doe, edith bourret courchesne, emit gamma, energy resolution, enriched uranium, fibers, formation of snowflake, germanium crystals, growth, luminosity, material scientist, nanocrystals, new opportunities, nnsa, nuclear materials. plutonium, polycrystalline form, scintillation properties, semiconductor germanium, single crystals, source of radiation, synthesis of crystals, thin epitaxial films, trial and error, united states, useful crystals

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

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

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

A Cyclotron’s Long Journey Home

By Guest PostMarch 2, 2013Scienceamerican science, atom smashers, atomic energy commission, aundra richards, berkeley hills, berkeley lab, brass cyclotron, circular particle accelerator, cyclotrons, david shirley, diameter, electron volts, ernest o lawrence, hall of science, hydrogen atoms, invention, kinetic energy, lab history, Large Hadron Collider, light, london science museum, merry go round, modern particle physics, natalie roe, nobel prize, nuclei, pamela patterson, paul alivisatos, protons, secret, Smithsonian, speed, the royal society, uk museum, university of california, Washington, yale university

One of the world’s first working circular particle accelerators returns to Berkeley Lab—75 years later.

Seventy-five years after one of the world’s first working cyclotrons was handed to the London Science Museum, it has returned to its birthplace in the Berkeley hills, where the man who invented it, Ernest O. Lawrence, helped launch the field of modern particle physics as well as the national laboratory that would bear his name, Lawrence Berkeley National Laboratory.

On Jan. 9, 1932 the brass cyclotron—which measures 26 inches from end to end and whose accelerating chamber measures just 11 inches in diameter—was successfully used to boost protons to energies of 1.22 million electron volts. Its return to Berkeley Lab caps a decades-long saga in which various parties endeavored to secure the cyclotron’s return from London, but the persistence of Pamela Patterson, who chronicles Berkeley Lab’s history as managing editor of its website, finally paid off. (more…)

A Dual Look at Photosystem II Using the World’s Most Powerful X-Ray Laser

By Guest PostFebruary 27, 2013Sciencealgae, berkeley lab, carbon dioxide, catalytic activities, cryogenic temperatures, cyanobacteria, data, earth, energy, free electron laser, green plants, jan kern, junko yano, laser pulses, lcls, light source, linac coherent, living cells, manganese calcium, metal ion, metalloenzyme crystal, metalloenzymes, mn4ca, molecular oxygen, most powerful, natural photosynthesis, nicholas sauter, nitrogen fixation, oxidation states, photo reduction, photon step cycle, photon steps, photosystem, protein complex, proteins, radiation damage, roberto alonso mori, s1 to s4, sensitive to radiation, simulate solar photons, slac, software tools, sunlight, uwe bergmann, vital to life, vittal yachandra, water, water molecules, world, xes, xfel, xray beams, xray diffraction, xray emission spectroscopy, xray laser, xrd

Berkeley Lab and SLAC Researchers Demonstrate Room Temperature Simultaneous Diffraction/Spectroscopy of Metalloenzymes

From providing living cells with energy, to nitrogen fixation, to the splitting of water molecules, the catalytic activities of metalloenzymes – proteins that contain a metal ion – are vital to life on Earth. A better understanding of the chemistry behind these catalytic activities could pave the way for exciting new technologies, most prominently artificial photosynthesis systems that would provide clean, green and renewable energy. Now, researchers with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) and the SLAC National Accelerator Laboratory have taken a major step towards achieving this goal.

Using ultrafast, intensely bright pulses of X-rays from SLAC’s Linac Coherent Light Source (LCLS), the world’s most powerful X-ray laser, the researchers were able to simultaneously image at room temperature the atomic and electronic structures of photosystem II, a metalloenzyme critical to photosynthesis. (more…)

Revealing the Secrets of Motility in Archaea

By Guest PostFebruary 24, 2013Scienceabrahjyoti ghosh, adenosine triphosphate, archaea, assembling archaella, atomic resolution, atp, atp in solution, atpase, bacterial flagellum, bacterial type, berkeley lab, c terminal domain, crystallography, ctd, domain of life, dynamic play, e coli, energy, enzyme, established model systems, filamentary grappling hook, flab filament, flah eye, flai, flai genes, flai protein structure, gareth williams, generate energy, Germany, glue, human cells, human gut, hyper flagellated, hyper motile mutants, iv pilus, john tainer, max planck institute, microbiota, microorganisms, motility, motor, mpi, n terminal domain, ntd, phosphate, protein structure, release, saxs, secretion of proteins, sonja verena albers, sulfolobus acidocaldarius, terrestrial microbiology, xray diffraction

Scientists from Berkeley Lab and the Max Planck Institute for Terrestrial Microbiology analyze a unique microbial motor

The protein structure of the motor that propels archaea has been characterized for the first time by a team of scientists from the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and Germany’s Max Planck Institute (MPI) for Terrestrial Microbiology.

The motility structure of this third domain of life has long been called a flagellum, a whip-like filament that, like the well-studied bacterial flagellum, rotates like a propeller. But although the archaeal structure has a similar function, it is so profoundly different in structure, genetics, and evolution that the researchers argue it deserves its own name: archaellum. (more…)