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  • richardmitnick 1:46 pm on August 26, 2014 Permalink | Reply
    Tags: Applied Research & Technology, , , , ,   

    From Berkeley Lab: “Competition for Graphene” 

    Berkeley Logo

    Berkeley Lab

    August 26, 2014
    Lynn Yarris (510) 486-5375

    A new argument has just been added to the growing case for graphene being bumped off its pedestal as the next big thing in the high-tech world by the two-dimensional semiconductors known as MX2 materials. An international collaboration of researchers led by a scientist with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) has reported the first experimental observation of ultrafast charge transfer in photo-excited MX2 materials. The recorded charge transfer time clocked in at under 50 femtoseconds, comparable to the fastest times recorded for organic photovoltaics.

    “We’ve demonstrated, for the first time, efficient charge transfer in MX2 heterostructures through combined photoluminescence mapping and transient absorption measurements,” says Feng Wang, a condensed matter physicist with Berkeley Lab’s Materials Sciences Division and the University of California (UC) Berkeley’s Physics Department. “Having quantitatively determined charge transfer time to be less than 50 femtoseconds, our study suggests that MX2 heterostructures, with their remarkable electrical and optical properties and the rapid development of large-area synthesis, hold great promise for future photonic and optoelectronic applications.”

    Feng Wang is a condensed matter physicist with Berkeley Lab’s Materials Sciences Division and UC Berkeley’s Physics Department. (Photo by Roy Kaltschmidt)

    Wang is the corresponding author of a paper in Nature Nanotechnology describing this research. The paper is titled Ultrafast charge transfer in atomically thin MoS2/WS2 heterostructures. Co-authors are Xiaoping Hong, Jonghwan Kim, Su-Fei Shi, Yu Zhang, Chenhao Jin, Yinghui Sun, Sefaattin Tongay, Junqiao Wu and Yanfeng Zhang.

    MX2 monolayers consist of a single layer of transition metal atoms, such as molybdenum (Mo) or tungsten (W), sandwiched between two layers of chalcogen atoms, such as sulfur (S). The resulting heterostructure is bound by the relatively weak intermolecular attraction known as the van der Waals force. These 2D semiconductors feature the same hexagonal “honeycombed” structure as graphene and superfast electrical conductance, but, unlike graphene, they have natural energy band-gaps. This facilitates their application in transistors and other electronic devices because, unlike graphene, their electrical conductance can be switched off.

    “Combining different MX2 layers together allows one to control their physical properties,” says Wang, who is also an investigator with the Kavli Energy NanoSciences Institute (Kavli-ENSI). “For example, the combination of MoS2 and WS2 forms a type-II semiconductor that enables fast charge separation. The separation of photoexcited electrons and holes is essential for driving an electrical current in a photodetector or solar cell.”

    In demonstrating the ultrafast charge separation capabilities of atomically thin samples of MoS2/WS2 heterostructures, Wang and his collaborators have opened up potentially rich new avenues, not only for photonics and optoelectronics, but also for photovoltaics.

    Photoluminescence mapping of a MoS2/WS2 heterostructure with the color scale representing photoluminescence intensity shows strong quenching of the MoS2 photoluminescence. (Image courtesy of Feng Wang group)

    “MX2 semiconductors have extremely strong optical absorption properties and compared with organic photovoltaic materials, have a crystalline structure and better electrical transport properties,” Wang says. “Factor in a femtosecond charge transfer rate and MX2 semiconductors provide an ideal way to spatially separate electrons and holes for electrical collection and utilization.”

    Wang and his colleagues are studying the microscopic origins of charge transfer in MX2 heterostructures and the variation in charge transfer rates between different MX2 materials.

    “We’re also interested in controlling the charge transfer process with external electrical fields as a means of utilizing MX2 heterostructures in photovoltaic devices,” Wang says.

    This research was supported by an Early Career Research Award from the DOE Office of Science through UC Berkeley, and by funding agencies in China through the Peking University in Beijing.

    See the full article here.

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

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  • richardmitnick 1:23 pm on August 26, 2014 Permalink | Reply
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    From SLAC: “X-ray Laser Probes Tiny Quantum Tornadoes in Superfluid Droplets” 

    SLAC Lab

    August 21, 2014

    An experiment at the Department of Energy’s SLAC National Accelerator Laboratory revealed a well-organized 3-D grid of quantum “tornadoes” inside microscopic droplets of supercooled liquid helium – the first time this formation has been seen at such a tiny scale.

    In this illustration, a patterned 3-D grid of tiny whirlpools, called quantum vortices, populates a nanoscale droplet of superfluid helium. Researchers found that in a micron-sized droplet, the density of vortices was 100,000 times greater than in any previous experiment on superfluids. An artistic rendering of a wheel-shaped droplet can be seen in the distance. (SLAC National Accelerator Laboratory)

    The findings by an international research team provide new insight on the strange nanoscale traits of a so-called “superfluid” state of liquid helium. When chilled to extremes, liquid helium behaves according to the rules of quantum mechanics that apply to matter at the smallest scales and defy the laws of classical physics. This superfluid state is one of just a few examples of quantum behavior on a large scale that makes the behavior easier to see and study.

    The results, detailed in the Aug. 22 issue of Science, could help shed light on similar quantum states, such as those in superconducting materials that conduct electricity with 100 percent efficiency or the strange collectives of particles, dubbed Bose-Einstein condensates, which act as a single unit.

    “What we found in this experiment was really surprising. We did not expect the beauty and clarity of the results,” said Christoph Bostedt, a co-leader of the experiment and a senior scientist at SLAC’s Linac Coherent Light Source (LCLS), the DOE Office of Science User Facility where the experiment was conducted.

    This instrument, called CAMP, was used for the helium nanodroplets experiment at the Linac Coherent Light Source’s Atomic, Molecular and Optical Science (AMO) experimental station. (SLAC National Accelerator Laboratory)

    “We were able to see a manifestation of the quantum world on a macroscopic scale,” said Ken Ferguson, a PhD student from Stanford University working at LCLS.

    While tiny tornadoes had been seen before in chilled helium, they hadn’t been seen in such tiny droplets, where they were packed 100,000 times more densely than in any previous experiment on superfluids, Ferguson said.

    Studying the Quantum Traits of a Superfluid

    Helium can be cooled to the point where it becomes a frictionless substance that remains liquid well below the freezing point of most fluids. The light, weakly attracting atoms have an endless wobble – a quantum state of perpetual motion that prevents them from freezing. The unique properties of superfluid helium, which have been the subject of several Nobel prizes, allow it to coat and climb the sides of a container, and to seep through molecule-wide holes that would have held in the same liquid at higher temperatures.

    In the LCLS experiment, researchers jetted a thin stream of helium droplets, like a nanoscale string of pearls, into a vacuum. Each droplet acquired a spin as it flew out of the jet, rotating up to 2 million turns per second, and cooled to a temperature colder than outer space. The X-ray laser took snapshots of individual droplets, revealing dozens of tiny twisters, called “quantum vortices,” with swirling cores that are the width of an atom.

    The fast rotation of the chilled helium nanodroplets caused a regularly spaced, dense 3-D pattern of vortices to form. This exotic formation, which resembles the ordered structure of a solid crystal and provides proof of the droplets’ quantum state, is far different than the lone whirlpool that would form in a regular liquid, such as briskly stirred cup of coffee.

    More Surprises in Store

    Researchers also discovered surprising shapes in some superfluid droplets. In a normal liquid, droplets can form peanut shapes when rotated swiftly, but the superfluid droplets took a very different form. About 1 percent of them formed unexpected wheel-like shapes and reached rotation speeds never before observed for their classical counterparts.

    Oliver Gessner, a senior scientist at Lawrence Berkeley Laboratory and a co-leader in the experiment, said, “Now that we have shown that we can detect and characterize quantum rotation in helium nanodroplets, it will be important to understand its origin and, ultimately, to try to control it.”

    Andrey Vilesov of the University of Southern California, the third experiment co-leader, added, “The experiment has exceeded our best expectations. Attaining proof of the vortices, their configurations in the droplets and the shapes of the rotating droplets was only possible with LCLS imaging.”

    He said further analysis of the LCLS data should yield more detailed information on the shape and arrangement of the vortices: “There will definitely be more surprises to come.”

    Other research collaborators were from the Stanford PULSE Institute; University of California, Berkeley; the Max Planck Society; Center for Free-Electron Laser Science at DESY; PNSensor GmbH; Chinese University of Hong Kong; and Kansas State University. This work was supported by the National Science Foundation, the U.S. Department of Energy Office of Science and the Max Planck Society.

    See the full article here.

    SLAC Campus
    SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the DOE’s Office of Science.

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  • richardmitnick 7:31 am on August 26, 2014 Permalink | Reply
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    From M.I.T.- “Study: Cutting emissions pays for itself” 

    MIT News

    August 24, 2014
    Audrey Resutek | Joint Program on the Science and Policy of Global Change

    Lower rates of asthma and other health problems are frequently cited as benefits of policies aimed at cutting carbon emissions from sources like power plants and vehicles, because these policies also lead to reductions in other harmful types of air pollution.

    But just how large are the health benefits of cleaner air in comparison to the costs of reducing carbon emissions? MIT researchers looked at three policies achieving the same reductions in the United States, and found that the savings on health care spending and other costs related to illness can be big — in some cases, more than 10 times the cost of policy implementation.

    Illustration: Christine Daniloff/MIT

    “Carbon-reduction policies significantly improve air quality,” says Noelle Selin, an assistant professor of engineering systems and atmospheric chemistry at MIT, and co-author of a study published today in Nature Climate Change. “In fact, policies aimed at cutting carbon emissions improve air quality by a similar amount as policies specifically targeting air pollution.”

    Selin and colleagues compared the health benefits to the economic costs of three climate policies: a clean-energy standard, a transportation policy, and a cap-and-trade program. The three were designed to resemble proposed U.S. climate policies, with the clean-energy standard requiring emissions reductions from power plants similar to those proposed in the Environmental Protection Agency’s Clean Power Plan.

    Health savings constant across policies

    The researchers found that savings from avoided health problems could recoup 26 percent of the cost to implement a transportation policy, but up to to 10.5 times the cost of implementing a cap-and-trade program. The difference depended largely on the costs of the policies, as the savings — in the form of avoided medical care and saved sick days — remained roughly constant: Policies aimed at specific sources of air pollution, such as power plants and vehicles, did not lead to substantially larger benefits than cheaper policies, such as a cap-and-trade approach.

    Savings from health benefits dwarf the estimated $14 billion cost of a cap-and-trade program. At the other end of the spectrum, a transportation policy with rigid fuel-economy requirements is the most expensive policy, costing more than $1 trillion in 2006 dollars, with health benefits recouping only a quarter of those costs. The price tag of a clean energy standard fell between the costs of the two other policies, with associated health benefits just edging out costs, at $247 billion versus $208 billion.

    “If cost-benefit analyses of climate policies don’t include the significant health benefits from healthier air, they dramatically underestimate the benefits of these policies,” says lead author Tammy Thompson, now at Colorado State University, who conducted the research as a postdoc in Selin’s group.

    Most detailed assessment to date

    The study is the most detailed assessment to date of the interwoven effects of climate policy on the economy, air pollution, and the cost of health problems related to air pollution. The MIT group paid especially close attention to how changes in emissions caused by policy translate into improvements in local and regional air quality, using comprehensive models of both the economy and the atmosphere.

    In addition to carbon dioxide, burning fossil fuels releases a host of other chemicals into the atmosphere. Some of these substances interact to form ground-level ozone, as well as fine particulate matter. The researchers modeled where and when these chemical reactions occurred, and where the resulting pollutants ended up — in cities where many people would come into contact with them, or in less populated areas.

    The researchers projected the health effects of ground-level ozone and fine particulate matter, two of the biggest health offenders related to fossil-fuel emissions. Both pollutants can cause asthma attacks and heart and lung disease, and can lead to premature death.

    In 2011, 231 counties in the U.S. exceeded the EPA’s regulatory standards for ozone, the main component of smog. Standards for fine particulate matter — airborne particles small enough to be inhaled deep into the lungs and even absorbed into the bloodstream — were exceeded in 118 counties.

    While cutting carbon dioxide from current levels in the U.S. will result in savings from better air quality, pollution-related benefits decline as carbon policies become more stringent. Selin cautions that after a certain point, most of the health benefits have already been reaped, and additional emissions reductions won’t translate into greater improvements.

    “While air-pollution benefits can help motivate carbon policies today, these carbon policies are just the first step,” Selin says. “To manage climate change, we’ll have to make carbon cuts that go beyond the initial reductions that lead to the largest air-pollution benefits.”

    The study shows that climate policies can also have significant local benefits not related to their impact on climate, says Gregory Nemet, a professor of public affairs and environmental studies at the University of Wisconsin at Madison who was not involved in the study.

    “A particularly notable aspect of this study is that even though several recent studies have shown large co-benefits, this study finds large co-benefits in the U.S., where air quality is assumed to be high relative to other countries,” Nemet says. “Now that states are on the hook to come up with plans to meet federal emissions targets by 2016, you can bet they will take a close look at these results.”

    This research was supported by funding from the EPA’s Science to Achieve Results program.

    See the full article here.

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  • richardmitnick 7:16 am on August 26, 2014 Permalink | Reply
    Tags: Applied Research & Technology, , , Microfluidics   

    From M.I.T.: “Sorting cells with sound waves” 

    MIT News

    August 25, 2014
    Anne Trafton | MIT News Office

    Acoustic device that separates tumor cells from blood cells could help assess cancer’s spread.

    Illustration: Christine Daniloff/MIT

    Researchers from MIT, Pennsylvania State University, and Carnegie Mellon University have devised a new way to separate cells by exposing them to sound waves as they flow through a tiny channel. Their device, about the size of a dime, could be used to detect the extremely rare tumor cells that circulate in cancer patients’ blood, helping doctors predict whether a tumor is going to spread.

    Separating cells with sound offers a gentler alternative to existing cell-sorting technologies, which require tagging the cells with chemicals or exposing them to stronger mechanical forces that may damage them.

    “Acoustic pressure is very mild and much smaller in terms of forces and disturbance to the cell. This is a most gentle way to separate cells, and there’s no artificial labeling necessary,” says Ming Dao, a principal research scientist in MIT’s Department of Materials Science and Engineering and one of the senior authors of the paper, which appears this week in the Proceedings of the National Academy of Sciences.

    Subra Suresh, president of Carnegie Mellon, the Vannevar Bush Professor of Engineering Emeritus, and a former dean of engineering at MIT, and Tony Jun Huang, a professor of engineering science and mechanics at Penn State, are also senior authors of the paper. Lead authors are MIT postdoc Xiaoyun Ding and Zhangli Peng, a former MIT postdoc who is now an assistant professor at the University of Notre Dame.

    The researchers have filed for a patent on the device, the technology of which they have demonstrated can be used to separate rare circulating cancer cells from white blood cells.

    To sort cells using sound waves, scientists have previously built microfluidic devices with two acoustic transducers, which produce sound waves on either side of a microchannel. When the two waves meet, they combine to form a standing wave (a wave that remains in constant position). This wave produces a pressure node, or line of low pressure, running parallel to the direction of cell flow. Cells that encounter this node are pushed to the side of the channel; the distance of cell movement depends on their size and other properties such as compressibility.

    However, these existing devices are inefficient: Because there is only one pressure node, cells can be pushed aside only short distances.

    The new device overcomes that obstacle by tilting the sound waves so they run across the microchannel at an angle — meaning that each cell encounters several pressure nodes as it flows through the channel. Each time it encounters a node, the pressure guides the cell a little further off center, making it easier to capture cells of different sizes by the time they reach the end of the channel.

    This simple modification dramatically boosts the efficiency of such devices, says Taher Saif, a professor of mechanical science and engineering at the University of Illinois at Urbana-Champaign. “That is just enough to make cells of different sizes and properties separate from each other without causing any damage or harm to them,” says Saif, who was not involved in this work.

    In this study, the researchers first tested the system with plastic beads, finding that it could separate beads with diameters of 9.9 and 7.3 microns (thousandths of a millimeter) with about 97 percent accuracy. They also devised a computer simulation that can predict a cell’s trajectory through the channel based on its size, density, and compressibility, as well as the angle of the sound waves, allowing them to customize the device to separate different types of cells.

    To test whether the device could be useful for detecting circulating tumor cells, the researchers tried to separate breast cancer cells known as MCF-7 cells from white blood cells. These two cell types differ in size (20 microns in diameter for MCF-7 and 12 microns for white blood cells), as well as density and compressibility. The device successfully recovered about 71 percent of the cancer cells; the researchers plan to test it with blood samples from cancer patients to see how well it can detect circulating tumor cells in clinical settings. Such cells are very rare: A 1-milliliter sample of blood may contain only a few tumor cells.

    “If you can detect these rare circulating tumor cells, it’s a good way to study cancer biology and diagnose whether the primary cancer has moved to a new site to generate metastatic tumors,” Dao says. “This method is a step forward for detection of circulating tumor cells in the body. It has the potential to offer a safe and effective new tool for cancer researchers, clinicians and patients,” Suresh says.

    The research was funded by the National Institutes of Health and the National Science Foundation.

    See the full article, with video, here.

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  • richardmitnick 6:38 am on August 26, 2014 Permalink | Reply
    Tags: Applied Research & Technology, Gerontology,   

    From Brown: “Care improves with culture change” 

    Brown University
    Brown University

    August 25, 2014
    David Orenstein 401-863-1862

    If a nursing home makes an extensive investment in “culture change” it will see improvements in quality of care, according to a new study led by Brown University gerontology researchers.

    Benefits of cultural change Creating warm residential-style common areas is one of many cultural changes that improve quality of care. Opportunities for residents to make choices, schedules that are less restrictive, and care decisions informed by front line staff are all part of cultural change. Photo: Wayne Dion for Tockwotton Home

    Culture change is a rethinking of nursing home operations and structure to allow a more residential lifestyle for residents, more resident choice in schedules and activities, and more front-line staff input into care management. Residents, for example, may become able to decide when to go to lunch and nurse’s aides may get a seat at the table in designing care processes. Across the country nursing homes are at various stages of implementing such changes, ranging from not at all to extensively.

    In the new study, a research team led by Susan Miller, professor of health services policy and practice at the Brown University School of Public Health, focused on homes that had recently accomplished some degree of implementation. Miller’s goal was not only to measure whether culture change introduction produced improvements in care quality but to do so for nursing homes that had implemented a similar extent of culture change practice by 2009-10.

    “What’s unique about this paper is that we stratified by the amount of implementation,” said Miller, senior author of the research published online in the Journal of the American Geriatrics Society.

    The study’s results come from surveys of directors of nursing at 824 homes in which Miller and her team assessed the degree of culture change implementation as of 2009-10. The researchers considered nursing homes that introduced culture change between 2005 and 2010, excluding homes that either had not adopted change or were especially early adopters.

    In their analysis Miller and her colleagues separated out the top quartile of implementers from the bottom three quartiles. For each group they looked at whether the list of 13 quality measures improved or worsened in the year after culture change introduction, compared to similar nursing homes that had not yet introduced it. They controlled for factors such as the homes’ occupancy rates, their mix of medical cases, and the degree of county-level competition.

    Degrees of quality improvement

    Upon introduction of culture change, the homes that implemented culture change most extensively produced statistically significant improvements in the percent of residents on bladder training programs, the percent of residents who required restraints, the proportion of residents with feeding tubes, and the percent with pressure ulcers. They also showed a nearly significant reduction in resident hospitalizations. No quality indicator became significantly worse.

    Among homes that implemented less culture change, the only significant improvement occurred in the number of Medicare/Medicaid health-related and quality of life survey deficiencies. (Miller said some nursing home administrators stated in interviews that they implemented those practices targeted by state surveyors.) Urinary tract infections and hospitalizations got slightly worse.

    No degree of culture change significantly improved other quality indicators such as the percent of residents with advanced directives or the proportion on antipscychotic medications. Falls did not get better, but they also did not get worse as some elder care observers had feared they would under culture change, Miller noted.

    The results help affirm that culture change can be effective in homes where the staff has embraced its patient-centered, flatter-management philosophy, Miller said.

    “It seems to be a valid notion to improve quality with adoption when you really adopt the philosophy and are doing a lot,” she said.

    In addition to Miller, the paper’s other authors are Michael Lepore, Julie Lima, Renee Shield, and Denise Tyler.

    The Retirement Research Foundation (grant 2008-086) and the National Institute on Aging (grant 1P01AG027296) funded the study.

    See the full article here.

    Welcome to Brown

    Rhode Island Hall: Rhode Island Hall’s classical exterior was recently renovated with a modern interiorRhode Island Hall: Rhode Island Hall’s classical exterior was recently renovated with a modern interior

    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.

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  • richardmitnick 6:02 am on August 26, 2014 Permalink | Reply
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    From phys.org: “Physicists ‘freeze time’ to manipulate spin information in graphene” 


    August 25, 2014
    Ans Hekkenberg

    Researchers from the FOM Foundation. and University of Groningen have found a way to preserve spin information for much longer than previously possible. They isolated the spin information from the influence of the outside world in a nanoscale graphene device, in which they can easily manipulate the information with electric fields. This feature makes their device an attractive candidate for future computer data storage and for logic devices based on spins. The researchers published their results online on 22 August 2014 in Physical Review Letters.

    Graphene is an atomic-scale honeycomb lattice made of carbon atoms.

    A schematic side view of the spintronics device. The dark grey graphene flake is protected by boron nitride layers (green). Voltages applied to the bottom electrode (bg) and the top electrode (tg) generate the electric field used for spin manipulation. The cobalt electrodes (numbered 1 to 5) are used to generate and detect spin information. Credit: Fundamental Research on Matter (FOM)

    The nanoscale device consists of a flake of graphene (a one-atom-thick layer of carbon) which is protected from the environment by stacked insulating layers of boron nitride. Electrons inside the graphene carry information: they each have a spin value (up or down), which is determined by the direction of their intrinsic magnetic moment. The spin values can be considered as computer bits, which can be used to transfer or store information.

    A challenge is that electron spins usually lose their values over time (the spin relaxation time), which causes information to be lost. In graphene, this usually takes about 0.2 nanoseconds (one nanosecond is a billionth of a second). However, with their protected device, the researchers managed to increase the spin relaxation time in graphene to more than 2 nanoseconds.

    Electric fields

    So far, physicists could only change the value of spins in graphene (and therefore the value of the ‘bits’) by using magnetic fields. Using two gate electrodes, the researchers now managed to manipulate the spin information in their device with electric fields instead. Since electric fields are much easier to generate in nanoscale devices, these results pave the way to future spintronic devices based on graphene.


    A optical microscope image of the spintronic device (top view). The top electrode (tg) and cobalt electrodes (1 to 5) are yellow. The boron nitride layers (in green) encapsulate the graphene flake, which is outlined by the dotted line. Credit: Fundamental Research on Matter (FOM)

    In the field of spintronics (which stands for spin and electronics), spin is used to convey information instead of electrical charges. Spin based devices have lower power consumption and are less volatile when compared to charge based ones. For this reason spintronic devices have been considered as an alternative for computer components, for instance in memory technologies like M-RAM and STT-RAM.

    See the full article here.

    About Phys.org in 100 Words

    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

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  • richardmitnick 5:26 pm on August 25, 2014 Permalink | Reply
    Tags: Applied Research & Technology, ,   

    From Argonne Lab: “Argonne, KAERI to develop prototype nuclear reactor “ 

    News from Argonne National Laboratory

    August 25, 2014
    No Writer Credit

    The U.S. Department of Energy’s Argonne National Laboratory has teamed up with the Korea Atomic Energy Research Institute (KAERI) to develop the Prototype Generation-IV Sodium-cooled Fast Reactor (PGSFR). KAERI’s Sodium-cooled Fast Reactor Development Agency has provided $6.78 million funding to date for Argonne’s contributions through a Work-for-Others contract.

    Argonne will support the Korean Atomic Energy Research Institute’s development of a Prototype Generation-IV Sodium-cooled Fast Reactor that incorporates an innovative metal fuel developed at Argonne. The fuel’s inherent safety potential was demonstrated in landmark tests conducted on the Experimental Breeder Reactor-II. Image credit: KAER I.

    Jong Kyung Kim, President of KAERI, visited Argonne today to execute the memorandum of understanding between KAERI and Argonne for a broad field of technical cooperation on nuclear science and technology, including the PGSFR project. “The technical cooperation between KAERI and Argonne plays a critical role in advancing cutting-edge technologies in nuclear energy,” said Argonne Director Peter Littlewood.

    The PGSFR is a 400 MWth, 150 MWe advanced sodium-cooled fast reactor that incorporates many innovative design features; in particular, metal fuel, which enables inherent safety characteristics. With Argonne support, KAERI is developing the reactor system while the Korean engineering and construction firm KEPCO E&C is designing the balance of the plant. The PGSFR Project aims to secure the Korean licensing authority’s design approval by the end of 2020, and the schedule calls for PGSFR to be commissioned by the end of 2028.

    The metal fuel technology base was developed at Argonne in the 1980s and ‘90s; its inherent safety potential was demonstrated in the landmark tests conducted on the Experimental Breeder Reactor-II in April 1986. They demonstrated the safe shutdown and cooling of the reactor without operator action following a simulated loss-of-cooling accident.

    “We are very excited about our collaboration on the PGSFR,” said Mark Peters, Argonne’s Associate Laboratory Director for Energy Engineering and Systems Analysis. “PGSFR is the world’s first new fast reactor that will use the technology developed at Argonne, and also the world’s first fast reactor that exploits inherent safety characteristics to prevent severe accidents.”

    The Argonne-KAERI collaboration on PGSFR was established following the U.S. Government authorization of the 10 CFR Part 810 request to transfer sodium-cooled fast reactor and low-enriched uranium fuel technology to the Republic of Korea.

    See the full article here.

    Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation’s first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America’s scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy’s Office of Science. For more visit http://www.anl.gov.

    The Advanced Photon Source at Argonne National Laboratory is one of five national synchrotron radiation light sources supported by the U.S. Department of Energy’s Office of Science to carry out applied and basic research to understand, predict, and ultimately control matter and energy at the electronic, atomic, and molecular levels, provide the foundations for new energy technologies, and support DOE missions in energy, environment, and national security. To learn more about the Office of Science X-ray user facilities, visit http://science.energy.gov/user-facilities/basic-energy-sciences/.

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

    Argonne Lab Campus

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  • richardmitnick 5:14 pm on August 25, 2014 Permalink | Reply
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    From SPACE.com: “NASA’s Robot Army of ‘Swarmies’ Could Explore Other Planets” 

    space-dot-com logo


    August 25, 2014
    Kelly Dickerson

    They may look like remote-controlled toy trucks, but a troop of new NASA robots could one day race across distant planets as a sort of space exploration vanguard.


    The autonomous robots, which engineers have dubbed “swarmies,” are much smaller than other NASA robots like the Mars rover Curiosity. Each comes equipped with a webcam, Wi-Fi antenna, and GPS system for navigation. The self-driving swarmie robots could be used to search alien surfaces one day. Credit: NASA/Dmitri Gerondidakis

    The swarmies function in a way similar to an ant colony. When one ant stumbles across a food source, it sends out a signal to the rest of the colony, and then the ants work together to cart the food back to the nest. Engineers from NASA’s Kennedy Space Center in Florida developed software that directs the swarmies to fan out in different directions and search for a specific, predetermined material, like ice-water on Mars. Once one of the rovers finds something interesting, it can use radio communication to call its robotic brethren over to help collect samples.

    “For a while people were interested in putting as much smarts and capability as they could on their one robot,” Kurt Leucht, one of the engineers working on the project, said in a statement. “Now people are realizing you can have much smaller, much simpler robots that can work together and achieve a task. One of them can roll over and die and it’s not the end of the mission because the others can still accomplish the task.”

    Working out a way to send humans on lunar or Martian exploration missions is complicated and expensive and those kinds of missions are likely still a long way off. Sending robots is an easier alternative, and NASA is working on a whole new generation of autonomous robotic explorers. NASA engineers have already dreamed up slithering snake-like robots that could explore Mars and deep-diving robots that could explore the oceans of Jupiter’s moon Europa.

    The RASSOR robot is programmed for digging and mining and will be incorporated into the swarmie test drives. Credit: NASA

    The swarmie tests are still in the preliminary stages, and NASA engineers are only driving the swarmies around the parking lots surrounding Kennedy’s Launch Control Center. Right now the robots are only programmed to hunt for barcoded slips of paper. Over the next few months, swarmie tests will also include RASSOR — a mining robot specially designed to dig into alien surfaces and search for interesting or valuable materials. The test will determine how well the swarming software translates to control other robotic vehicles.

    Swarmies might also find a use on Earth, NASA officials said. The robots could aid in rescue missions following natural disasters or building collapses, crashes and other wreckage sites. The robots would also make perfect pipeline inspectors.

    “This would give you something smaller and cheaper that could always be running up and down the length of the pipeline so you would always know the health of your pipelines,” Cheryle Mako, a NASA engineer who is leading the project, said in a statement. “If we had small swarming robots that had a couple sensors and knew what they were looking for, you could send them out to a leak site and find which area was at greatest risk.”

    See the full article here.


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  • richardmitnick 4:57 pm on August 25, 2014 Permalink | Reply
    Tags: Applied Research & Technology, ,   

    From Astrobiology: “Alternate mechanism of species formation picks up support, thanks to a South American ant” 

    Astrobiology Magazine

    Astrobiology Magazine

    Aug 25, 2014
    Source: University of Rochester

    A newly-discovered species of ant supports a controversial theory of species formation. The ant, only found in a single patch of eucalyptus trees on the São Paulo State University campus in Brazil, branched off from its original species while living in the same colony, something thought rare in current models of evolutionary development.

    “Most new species come about in geographic isolation,” said Christian Rabeling, assistant professor of biology at the University of Rochester. “We now have evidence that speciation can take place within a single colony.”

    The findings by Rabeling and the research team were published today in the journal Current Biology.

    In discovering the parasitic Mycocepurus castrator, Rabeling and his colleagues uncovered an example of a still-controversial theory known as sympatric speciation, which occurs when a new species develops while sharing the same geographic area with its parent species, yet reproducing on its own.“While sympatric speciation is more difficult to prove,” said Rabeling, “we believe we are in the process of actually documenting a particular kind of evolution-in-progress.”

    New species are formed when its members are no longer able to reproduce with members of the parent species. The commonly-accepted mechanism is called allopatric speciation, in which geographic barriers—such as mountains—separate members of a group, causing them to evolve independently.

    “Since [Charles] Darwin’s Origin of Species, evolutionary biologists have long debated whether two species can evolve from a common ancestor without being geographically isolated from each other,” said Ted Schultz, curator of ants at the Smithsonian’s National Museum of Natural History and co-author of the study. “With this study, we offer a compelling case for sympatric evolution that will open new conversations in the debate about speciation in these ants, social insects and evolutionary biology more generally.”

    A queen ant of the parasitic species Mycocepurus castrator. Credit: Christian Rabeling/University of Rochester

    M. castrator is not simply another ant in the colony; it’s a parasite that lives with—and off of—its host, Mycocepurus goeldii. The host is a fungus-growing ant that cultivates fungus for its nutritional value, both for itself and, indirectly, for its parasite, which does not participate in the work of growing the fungus garden.

    That led the researchers to study the genetic relationships of all fungus-growing ants in South America, including all five known and six newly discovered species of the genus Mycocepurus, to determine whether the parasite did evolve from its presumed host. They found that the parasitic ants were, indeed, genetically very close to M. goeldii, but not to the other ant species.

    They also determined that the parasitic ants were no longer reproductively compatible with the host ants—making them a unique species—and had stopped reproducing with their host a mere 37,000 years ago—a very short period on the evolutionary scale.

    A big clue for the research team was found by comparing the ants’ genes, both in the cell’s nucleus as well as in the mitochondria—the energy-producing structures in the cells. Genes are made of units called nucleotides, and Rabeling found that the sequencing of those nucleotides in the mitochondria is beginning to look different from what is found in the host ants, but that the genes in the nucleus still have traces of the relationship between host and parasite, leading him to conclude that M. castrator has begun to evolve away from its host.

    Rabeling explained that just comparing some nuclear and mitochondrial genes may not be enough to demonstrate that the parasitic ants are a completely new species. “We are now sequencing the entire mitochondrial and nuclear genomes of these parasitic ants and their host in an effort to confirm speciation and the underlying genetic mechanism.”

    The parasitic ants need to exercise discretion because taking advantage of the host species is considered taboo in ant society. Offending ants have been known to be killed by worker mobs. As a result, the parasitic queen of the new species has evolved into a smaller size, making them difficult to distinguish from a host worker.

    Host queens and males reproduce in an aerial ceremony, in the wet tropics only during a particular season when it begins to rain. Rabeling found that the parasitic queens and males, needing to be more discreet about their reproductive activities, diverge from the host’s mating pattern. By needing to hide their parasitic identity, M. castrator males and females lost their special adaptations that allowed them to reproduce in flight, and mate inside the host nest, making it impossible for them to sexually interact with their host species.

    See the full article here.


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  • richardmitnick 4:07 pm on August 25, 2014 Permalink | Reply
    Tags: Applied Research & Technology, , , , University of Chicago   

    From Argonne Lab: “Gut bacteria that protect against food allergies identified” 

    News from Argonne National Laboratory

    August 25, 2014
    This story was first reported by the University of Chicago Medicine and Biological Sciences.

    The presence of Clostridia, a common class of gut bacteria, protects against food allergies, a new study in mice finds. By inducing immune responses that prevent food allergens from entering the bloodstream, Clostridia minimize allergen exposure and prevent sensitization – a key step in the development of food allergies. The discovery points toward probiotic therapies for this so-far untreatable condition, report scientists from the University of Chicago, Aug. 25 in the Proceedings of the National Academy of Sciences.

    One variety of many of Clostridia

    “From a basic science perspective, what is fascinating with this research is the fine-scale machinations that the host microbiome exhibits with its host,” said Dionysios Antonopoulos of the Institute for Genomics and Systems Biology at Argonne National Laboratory and a co-author for the study. “Specific populations of microorganisms serve specific functions in mediating how the host’s immune system senses and interacts with its environment. As with this study, understanding how specific populations of the microbial community are impacted by antibiotics or diet provides a guide on what therapeutic strategies need to be developed to restore a healthy state.”

    Although the causes of food allergy – a sometimes deadly immune response to certain foods – are unknown, studies have hinted that modern hygienic or dietary practices may play a role by disturbing the body’s natural bacterial composition. In recent years, food allergy rates among children have risen sharply – increasing approximately 50 percent between 1997 and 2011 – and studies have shown a correlation to antibiotic and antimicrobial use.

    “Environmental stimuli such as antibiotic overuse, high fat diets, caesarean birth, removal of common pathogens and even formula feeding have affected the microbiota with which we’ve co-evolved,” said study senior author Cathryn Nagler, PhD, Bunning Food Allergy Professor at the University of Chicago. “Our results suggest this could contribute to the increasing susceptibility to food allergies.”

    To test how gut bacteria affect food allergies, Nagler and her team investigated the response to food allergens in mice. They exposed germ-free mice (born and raised in sterile conditions to have no resident microorganisms) and mice treated with antibiotics as newborns (which significantly reduces gut bacteria) to peanut allergens. Both groups of mice displayed a strong immunological response, producing significantly higher levels of antibodies against peanut allergens than mice with normal gut bacteria.

    This sensitization to food allergens could be reversed, however, by reintroducing a mix of Clostridia bacteria back into the mice. Reintroduction of another major group of intestinal bacteria, Bacteroides, failed to alleviate sensitization, indicating that Clostridia have a unique, protective role against food allergens.

    Closing the door

    To identify this protective mechanism, Nagler and her team studied cellular and molecular immune responses to bacteria in the gut. Genetic analysis revealed that Clostridia caused innate immune cells to produce high levels of interleukin-22 (IL-22), a signaling molecule known to decrease the permeability of the intestinal lining.

    Antibiotic-treated mice were either given IL-22 or were colonized with Clostridia. When exposed to peanut allergens, mice in both conditions showed reduced allergen levels in their blood, compared to controls. Allergen levels significantly increased, however, after the mice were given antibodies that neutralized IL-22, indicating that Clostridia-induced IL-22 prevents allergens from entering the bloodstream.

    “We’ve identified a bacterial population that protects against food allergen sensitization,” Nagler said. “The first step in getting sensitized to a food allergen is for it to get into your blood and be presented to your immune system. The presence of these bacteria regulates that process.” She cautions, however, that these findings likely apply at a population level, and that the cause-and-effect relationship in individuals requires further study.

    While complex and largely undetermined factors such as genetics greatly affect whether individuals develop food allergies and how they manifest, the identification of a bacteria-induced barrier-protective response represents a new paradigm for preventing sensitization to food. Clostridia bacteria are common in humans and represent a clear target for potential therapeutics that prevent or treat food allergies. Nagler and her team are working to develop and test compositions that could be used for probiotic therapy and have filed a provisional patent.

    “It’s exciting because we know what the bacteria are; we have a way to intervene,” Nagler said. “There are of course no guarantees, but this is absolutely testable as a therapeutic against a disease for which there’s nothing. As a mom, I can imagine how frightening it must be to worry every time your child takes a bite of food.”

    “Food allergies affect 15 million Americans, including one in 13 children, who live with this potentially life-threatening disease that currently has no cure,” said Mary Jane Marchisotto, senior vice president of research at Food Allergy Research & Education. “We have been pleased to support the research that has been conducted by Dr. Nagler and her colleagues at the University of Chicago.”

    The study, Commensal bacteria protect against food allergen sensitization, was supported by Food Allergy Research & Education (FARE) and the University of Chicago Digestive Diseases Research Core Center. Gene sequencing was conducted at the Next-Generation Sequencing Core at Argonne National Labortory. Additional authors include Andrew T. Stefka, Taylor Feehley, Prabhanshu Tripathi, Ju Qiu, Kathy D. McCoy, Sarkis K. Mazmanian, Melissa Y. Tjota, Goo-Young Seo, Severine Cao, Betty R. Theriault, Dionysios A. Antonopoulos, Liang Zhou, Eugene B. Chang and Yang-Xin Fu.

    Food Allergy Research & Education (FARE) is a 501(c)(3) nonprofit organization that seeks to find a cure for food allergies while keeping affected individuals safe and included. FARE does this by investing in world-class research that advances the treatment and understanding of the disease, providing evidence-based education and resources, undertaking advocacy at all levels of government and increasing awareness of food allergy as a serious public health issue.

    The University of Chicago Medicine and Biological Sciences is one of the nation’s leading academic medical institutions. It comprises the Pritzker School of Medicine, a top medical school in the nation; the University of Chicago Biological Sciences Division; and the University of Chicago Medical Center, which recently opened the Center for Care and Discovery, a $700 million specialty medical facility. Twelve Nobel Prize winners in physiology or medicine have been affiliated with the University of Chicago Medicine.

    See the full article here.

    Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation’s first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America’s scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy’s Office of Science. For more visit http://www.anl.gov.

    The Advanced Photon Source at Argonne National Laboratory is one of five national synchrotron radiation light sources supported by the U.S. Department of Energy’s Office of Science to carry out applied and basic research to understand, predict, and ultimately control matter and energy at the electronic, atomic, and molecular levels, provide the foundations for new energy technologies, and support DOE missions in energy, environment, and national security. To learn more about the Office of Science X-ray user facilities, visit http://science.energy.gov/user-facilities/basic-energy-sciences/.

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

    Argonne Lab Campus

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