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  • richardmitnick 1:45 pm on October 17, 2014 Permalink | Reply
    Tags: Applied Research & Technology, ,   

    From AAAS: “Would-be drug mimics ‘good’ cholesterol” 

    AAAS

    AAAS

    16 October 2014
    Robert F. Service

    A new drug candidate designed to mimic the body’s “good” cholesterol shows a striking ability in mice to lower cholesterol levels in the blood and dissolve artery-clogging plaques. What’s more, the compound works when given orally, rather than as an injection. If the results hold true in humans—a big if, given past failures at transferring promising treatments from mice—it could provide a new way to combat atherosclerosis, the biggest killer in developed countries.

    Although doctors already have effective cholesterol-lowering agents, such as statins, at their disposal, there’s room for improvement. Statins have significant side effects in some people and don’t always reduce cholesterol enough in others. “There is still plenty of heart disease out there even among people who take statins,” says Godfrey Getz, an experimental pathologist at the University of Chicago in Illinois.

    For that reason, researchers around the globe are searching for novel drugs that affect cholesterol levels in one of two ways. The first has been to reduce levels of low-density lipoprotein (LDL), commonly known as bad cholesterol, which has been associated with higher heart disease risk. This is the goal of statins, which block an enzyme involved in cholesterol production. The second strategy is to increase levels of good cholesterol, or high-density lipoprotein (HDL), which seems to boost heart health in people who have a lot of it. But producing HDL-raising drugs that prevent heart disease has proven difficult. In the body, a large protein called apolipoprotein A-I (apoA-I) wraps around fatty lipid molecules to create HDL particles that sop up LDL and ferry it to the liver where it is eliminated. So for several decades researchers have been designing and testing small protein fragments called peptides to see if they could mimic the behavior of apoA-I. One such peptide, known as 4F, did not reduce serum cholesterol levels, but it did shrink arterial plaques in mice, rabbits, and monkeys. And in an early clinical trial by researchers at Bruin Pharma Inc. in Beverly Hills, California, that was designed only to measure its safety in people, 4F didn’t appear to show any beneficial effect.

    pro
    Multiple copies of a four-armed peptide wrap around lipids to create particles that mimic the behavior of HDL, the “good” cholesterol.
    Y.Zhao et al., J. Am. Chem. Soc

    M. Reza Ghadiri, a chemist at the Scripps Research Institute in San Diego, California, and his colleagues took a slightly different tack, creating a peptide that mimics another part of the apoA-I protein than 4F does. Initial in vitro studies suggested the peptide formed HDL-like particles and sopped up LDL, an encouraging result that prompted them to push it further. Ghadiri and his Scripps colleagues have now tested their compound in mice that develop artery clogging plaques when fed a Western-style high-fat diet. One group of animals received the peptide intravenously. For another group, the researchers simply added the compound to the animals’ water, a strategy they considered unlikely to work, because the gut contains high amounts of proteases designed to chop proteins apart. To their surprise, in both groups, serum cholesterol levels dropped 40% from their previous levels within 2 weeks of starting to take the drug. And by 10 weeks, the number of artery-clogging lesions had been reduced by half, the team reports in the October issue of the Journal of Lipid Research. What remains puzzling, however, is that Ghadiri and his colleagues did not detect their peptides in the blood of their test animal. Ghadiri says this suggests that the new peptide may work by removing cholesterol precursors in the gut before they enter the bloodstream.

    “It’s a very interesting result,” Getz says. But he cautions that the work has been tested only in animals, and many therapies—including the closely related 4F peptide—fail to transfer to humans. That said, Getz notes that some of the initial promising results with this peptide and other apoA-I mimics offer hope that researchers may soon come up with novel drugs capable of dissolving artery-clogging plaques before they can wreak their havoc.

    See the full article here.

    The American Association for the Advancement of Science is an international non-profit organization dedicated to advancing science for the benefit of all people.

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  • richardmitnick 9:02 am on October 17, 2014 Permalink | Reply
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    From MIT: “Nanoparticles get a magnetic handle” 


    MIT News

    October 9, 2014
    David L. Chandler | MIT News Office

    A long-sought goal of creating particles that can emit a colorful fluorescent glow in a biological environment, and that could be precisely manipulated into position within living cells, has been achieved by a team of researchers at MIT and several other institutions. The finding is reported this week in the journal Nature Communications.

    4
    Elemental mapping of the location of iron atoms (blue) in the magnetic nanoparticles and cadmium (red) in the fluorescent quantum dots provide a clear visualization of the way the two kinds of particles naturally separate themselves into a core-and-shell structure. Image courtesy of the researchers

    The new technology could make it possible to track the position of the nanoparticles as they move within the body or inside a cell. At the same time, the nanoparticles could be manipulated precisely by applying a magnetic field to pull them along. And finally, the particles could have a coating of a bioreactive substance that could seek out and bind with particular molecules within the body, such as markers for tumor cells or other disease agents.

    “It’s been a dream of mine for many years to have a nanomaterial that incorporates both fluorescence and magnetism in a single compact object,” says Moungi Bawendi, the Lester Wolfe Professor of Chemistry at MIT and senior author of the new paper. While other groups have achieved some combination of these two properties, Bawendi says that he “was never very satisfied” with results previously achieved by his own team or others.

    For one thing, he says, such particles have been too large to make practical probes of living tissue: “They’ve tended to have a lot of wasted volume,” Bawendi says. “Compactness is critical for biological and a lot of other applications.”

    In addition, previous efforts were unable to produce particles of uniform and predictable size, which could also be an essential property for diagnostic or therapeutic applications.

    Moreover, Bawendi says, “We wanted to be able to manipulate these structures inside the cells with magnetic fields, but also know exactly what it is we’re moving.” All of these goals are achieved by the new nanoparticles, which can be identified with great precision by the wavelength of their fluorescent emissions.

    The new method produces the combination of desired properties “in as small a package as possible,” Bawendi says — which could help pave the way for particles with other useful properties, such as the ability to bind with a specific type of bioreceptor, or another molecule of interest.

    In the technique developed by Bawendi’s team, led by lead author and postdoc Ou Chen, the nanoparticles crystallize such that they self-assemble in exactly the way that leads to the most useful outcome: The magnetic particles cluster at the center, while fluorescent particles form a uniform coating around them. That puts the fluorescent molecules in the most visible location for allowing the nanoparticles to be tracked optically through a microscope.

    “These are beautiful structures, they’re so clean,” Bawendi says. That uniformity arises, in part, because the starting material, fluorescent nanoparticles that Bawendi and his group have been perfecting for years, are themselves perfectly uniform in size. “You have to use very uniform material to produce such a uniform construction,” Chen says.

    Initially, at least, the particles might be used to probe basic biological functions within cells, Bawendi suggests. As the work continues, later experiments may add additional materials to the particles’ coating so that they interact in specific ways with molecules or structures within the cell, either for diagnosis or treatment.

    The ability to manipulate the particles with electromagnets is key to using them in biological research, Bawendi explains: The tiny particles could otherwise get lost in the jumble of molecules circulating within a cell. “Without a magnetic ‘handle,’ it’s like a needle in a haystack,” he says. “But with the magnetism, you can find it easily.”

    A silica coating on the particles allows additional molecules to attach, causing the particles to bind with specific structures within the cell. “Silica makes it completely flexible; it’s a well developed material that can bind to almost anything,” Bawendi says.

    For example, the coating could have a molecule that binds to a specific type of tumor cells; then, “You could use them to enhance the contrast of an MRI, so you could see the spatial macroscopic outlines of a tumor,” he says.

    The next step for the team is to test the new nanoparticles in a variety of biological settings. “We’ve made the material,” Chen says. “Now we’ve got to use it, and we’re working with a number of groups around the world for a variety of applications.”

    Christopher Murray, a professor of chemistry and materials science and engineering at the University of Pennsylvania who was not connected with this research, says, “This work exemplifies the power of using nanocrystals as building blocks for multiscale and multifunctional structures. We often use the term ‘artificial atoms’ in the community to describe how we are exploiting a new periodic table of fundamental building blocks to design materials, and this is a very elegant example.”

    The study included researchers at MIT; Massachusetts General Hospital; Institut Curie in Paris; the Heinrich-Pette Institute and the Bernhard-Nocht Institute for Tropical Medicine in Hamburg, Germany; Children’s Hospital Boston; and Cornell University. The work was supported by the National Institutes of Health, the Army Research Office through MIT’s Institute for Soldier Nanotechnologies, and the Department of Energy.

    See the full article, with video, here.

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  • richardmitnick 8:38 am on October 17, 2014 Permalink | Reply
    Tags: Applied Research & Technology, , , ,   

    From UC Berkeley: “New front in war on Alzheimer’s, other protein-folding diseases” 

    UC Berkeley

    UC Berkeley

    October 16, 2014
    Robert Sanders

    A surprise discovery that overturns decades of thinking about how the body fixes proteins that come unraveled greatly expands opportunities for therapies to prevent diseases such as Alzheimer’s and Parkinson’s, which have been linked to the accumulation of improperly folded proteins in the brain.

    “This finding provides a whole other outlook on protein-folding diseases; a new way to go after them,” said Andrew Dillin, the Thomas and Stacey Siebel Distinguished Chair of Stem Cell Research in the Department of Molecular and Cell Biology and Howard Hughes Medical Institute investigator at the University of California, Berkeley.

    br
    A cell suffering heat shock is like a country besieged, where attackers first sever lines of communications. The pat-10 gene helps repair communication to allow chaperones to treat misfolded proteins. (Andrew Dillin graphic)

    Dillin, UC Berkeley postdoctoral fellows Nathan A. Baird and Peter M. Douglas and their colleagues at the University of Michigan, The Scripps Research Institute and Genentech Inc., will publish their results in the Oct. 17 issue of the journal Science.

    Cells put a lot of effort into preventing proteins – which are like a string of beads arranged in a precise three-dimensional shape – from unraveling, since a protein’s activity as an enzyme or structural component depends on being properly shaped and folded. There are at least 350 separate molecular chaperones constantly patrolling the cell to refold misfolded proteins. Heat is one of the major threats to proteins, as can be demonstrated when frying an egg – the clear white albumen turns opaque as the proteins unfold and then tangle like spaghetti.

    Heat shock

    For 35 years, researchers have worked under the assumption that when cells undergo heat shock, as with a fever, they produce a protein that triggers a cascade of events that field even more chaperones to refold unraveling proteins that could kill the cell. The protein, HSF-1 (heat shock factor-1), does this by binding to promoters upstream of the 350-plus chaperone genes, upping the genes’ activity and launching the army of chaperones, which originally were called “heat shock proteins.”

    Injecting animals with HSF-1 has been shown not only to increase their tolerance of heat stress, but to increase lifespan.

    Because an accumulation of misfolded proteins has been implicated in aging and in neurodegenerative diseases such as Alzheimer’s, Parkinson’s and Huntington’s diseases, scientists have sought ways to artificially boost HSF-1 in order to reduce the protein plaques and tangles that eventually kill brain cells. To date, such boosters have extended lifespan in lab animals, including mice, but greatly increased the incidence of cancer.

    Dillin’s team found in experiments on the nematode worm C. elegans that HSF-1 does a whole lot more than trigger release of chaperones. An equal if not more important function is to stabilize the cell’s cytoskeleton, which is the highway that transports essential supplies – healing chaperones included – around the cell.

    “We are suggesting that, rather than making more of HSF-1 to prevent diseases like Huntington’s, we should be looking for ways to make the actin cytoskeleton better,” Dillin said. Such tactics might avoid the carcinogenic side effects of upping HSF-1.

    Dillin is codirector of the Paul F. Glenn Center for Aging Research, a new collaboration between UC Berkeley and UC San Francisco supported by the Glenn Foundation for Medical Research. Center investigators will study the many ways that proteins malfunction within cells, ideally paving the way for novel treatments for neurodegenerative diseases.

    A cell at war

    Dillin compares a cell experiencing heat shock to a country under attack. In a war, an aggressor first cuts off all communications, such as roads, train and bridges, which prevents the doctors from treating the wounded. Similarly, heat shock disrupts the cytoskeletal highway, preventing the chaperone “doctors” from reaching the patients, the misfolded proteins.

    chap
    Chaperones help newborn proteins (polypeptides) fold properly, but also fix misfolded proteins.

    “We think HSF-1 not only makes more chaperones, more doctors, but also insures that the roadways stay intact to keep everything functional and make sure the chaperones can get to the sick and wounded warriors,” he said.

    The researchers found specifically that HSF-1 up-regulates another gene, pat-10, that produces a protein that stabilizes actin, the building blocks of the cytoskeleton.

    By boosting pat-10 activity, they were able to cure worms that had been altered to express the Huntington’s disease gene, and also extend the lifespan of normal worms.

    Dillin suspects that HSF-1’s main function is, in fact, to protect the actin cytoskeleton. He and his team mutated HSF-1 so that it no longer boosted chaperones, demonstrating, he said, that “you can survive heat shock with the normal level of heat shock proteins, as long as you make your cytoskeleton work better.”

    He noted that the team’s results – that boosting chaperones is not essential to surviving heat stress – were so contradictory to current thinking that “I made my post-docs’ lives hell for three years” insisting on more experiments to rule out errors. Yet, when Dillin presented the results recently to members of the protein-folding community, he said the first reaction of many was, “That makes perfect sense.”

    Dillin’s colleagues include Milos S. Simic and Suzanne C. Wolff of UC Berkeley, Ana R. Grant of the University of Michigan in Ann Arbor, James J. Moresco and John R. Yates III of Scripps in La Jolla, Calif., and Gerard Manning of Genentech, South San Francisco, Calif. The work is funded by the Howard Hughes Medical Institute as well as by the National Institute of General Medical Sciences (8 P41 GM103533-17) and National Institute on Aging (R01AG027463-04) of the National Institutes of Health.

    See the full article here.

    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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  • richardmitnick 8:20 am on October 17, 2014 Permalink | Reply
    Tags: Applied Research & Technology, , ,   

    From MIT: “Superconducting circuits, simplified” 


    MIT News

    October 17, 2014
    Larry Hardesty | MIT News Office

    Computer chips with superconducting circuits — circuits with zero electrical resistance — would be 50 to 100 times as energy-efficient as today’s chips, an attractive trait given the increasing power consumption of the massive data centers that power the Internet’s most popular sites.

    chip
    Shown here is a square-centimeter chip containing the nTron adder, which performed the first computation using the researchers’ new superconducting circuit. Photo: Adam N. McCaughan

    Superconducting chips also promise greater processing power: Superconducting circuits that use so-called Josephson junctions have been clocked at 770 gigahertz, or 500 times the speed of the chip in the iPhone 6.

    But Josephson-junction chips are big and hard to make; most problematic of all, they use such minute currents that the results of their computations are difficult to detect. For the most part, they’ve been relegated to a few custom-engineered signal-detection applications.

    In the latest issue of the journal Nano Letters, MIT researchers present a new circuit design that could make simple superconducting devices much cheaper to manufacture. And while the circuits’ speed probably wouldn’t top that of today’s chips, they could solve the problem of reading out the results of calculations performed with Josephson junctions.

    The MIT researchers — Adam McCaughan, a graduate student in electrical engineering, and his advisor, professor of electrical engineering and computer science Karl Berggren — call their device the nanocryotron, after the cryotron, an experimental computing circuit developed in the 1950s by MIT professor Dudley Buck. The cryotron was briefly the object of a great deal of interest — and federal funding — as the possible basis for a new generation of computers, but it was eclipsed by the integrated circuit.

    “The superconducting-electronics community has seen a lot of devices come and go, without any real-world application,” McCaughan says. “But in our paper, we have already applied our device to applications that will be highly relevant to future work in superconducting computing and quantum communications.”

    Superconducting circuits are used in light detectors that can register the arrival of a single light particle, or photon; that’s one of the applications in which the researchers tested the nanocryotron. McCaughan also wired together several of the circuits to produce a fundamental digital-arithmetic component called a half-adder.

    Resistance is futile

    Superconductors have no electrical resistance, meaning that electrons can travel through them completely unimpeded. Even the best standard conductors — like the copper wires in phone lines or conventional computer chips — have some resistance; overcoming it requires operational voltages much higher than those that can induce current in a superconductor. Once electrons start moving through an ordinary conductor, they still collide occasionally with its atoms, releasing energy as heat.

    Superconductors are ordinary materials cooled to extremely low temperatures, which damps the vibrations of their atoms, letting electrons zip past without collision. Berggren’s lab focuses on superconducting circuits made from niobium nitride, which has the relatively high operating temperature of 16 Kelvin, or minus 257 degrees Celsius. That’s achievable with liquid helium, which, in a superconducting chip, would probably circulate through a system of pipes inside an insulated housing, like Freon in a refrigerator.

    A liquid-helium cooling system would of course increase the power consumption of a superconducting chip. But given that the starting point is about 1 percent of the energy required by a conventional chip, the savings could still be enormous. Moreover, superconducting computation would let data centers dispense with the cooling systems they currently use to keep their banks of servers from overheating.

    Cheap superconducting circuits could also make it much more cost-effective to build single-photon detectors, an essential component of any information system that exploits the computational speedups promised by quantum computing.

    Engineered to a T

    The nanocryotron — or nTron — consists of a single layer of niobium nitride deposited on an insulator in a pattern that looks roughly like a capital “T.” But where the base of the T joins the crossbar, it tapers to only about one-tenth its width. Electrons sailing unimpeded through the base of the T are suddenly crushed together, producing heat, which radiates out into the crossbar and destroys the niobium nitride’s superconductivity.

    A current applied to the base of the T can thus turn off a current flowing through the crossbar. That makes the circuit a switch, the basic component of a digital computer.

    After the current in the base is turned off, the current in the crossbar will resume only after the junction cools back down. Since the superconductor is cooled by liquid helium, that doesn’t take long. But the circuits are unlikely to top the 1 gigahertz typical of today’s chips. Still, they could be useful for some lower-end applications where speed isn’t as important as energy efficiency.

    Their most promising application, however, could be in making calculations performed by Josephson junctions accessible to the outside world. Josephson junctions use tiny currents that until now have required sensitive lab equipment to detect. They’re not strong enough to move data to a local memory chip, let alone to send a visual signal to a computer monitor.

    In experiments, McCaughan demonstrated that currents even smaller than those found in Josephson-junction devices were adequate to switch the nTron from a conductive to a nonconductive state. And while the current in the base of the T can be small, the current passing through the crossbar could be much larger — large enough to carry information to other devices on a computer motherboard.

    “I think this is a great device,” says Oleg Mukhanov, chief technology officer of Hypres, a superconducting-electronics company whose products rely on Josephson junctions. “We are currently looking very seriously at the nTron for use in memory.”

    “There are several attractions of this device,” Mukhanov says. “First, it’s very compact, because after all, it’s a nanowire. One of the problems with Josephson junctions is that they are big. If you compare them with CMOS transistors, they’re just physically bigger. The second is that Josephson junctions are two-terminal devices. Semiconductor transistors are three-terminal, and that’s a big advantage. Similarly, nTrons are three-terminal devices.”

    “As far as memory is concerned,” Mukhanov adds, “one of the features that also attracts us is that we plan to integrate it with magnetoresistive spintronic devices, mRAM, magnetic random-access memories, at room temperature. And one of the features of these devices is that they are high-impedance. They are in the kilo-ohms range, and if you look at Josephson junctions, they are just a few ohms. So there is a big mismatch, which makes it very difficult from an electrical-engineering standpoint to match these two devices. NTrons are nanowire devices, so they’re high-impedance, too. They’re naturally compatible with the magnetoresistive elements.”

    McCaughan and Berggren’s research was funded by the National Science Foundation and by the Director of National Intelligence’s Intelligence Advanced Research Projects Activity.

    See the full article here.

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  • richardmitnick 9:04 pm on October 16, 2014 Permalink | Reply
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    From LLNL: “Lab, UC Davis partner to personalize cancer medications” 


    Lawrence Livermore National Laboratory

    10/16/2014
    Stephen P Wampler, LLNL, (925) 423-3107, wampler1@llnl.gov

    Buoyed by several dramatic advances, Lawrence Livermore National Laboratory scientists think they can tackle biological science in a way that couldn’t be done before.

    Over the past two years, Lab researchers have expedited accelerator mass spectrometer sample preparation and analysis time from days to minutes and moved a complex scientific process requiring accelerator physicists into routine laboratory usage.

    Ken Turteltaub, the leader of the Lab’s Biosciences and Biotechnology Division, sees the bio AMS advances as allowing researchers to undertake quantitative assessments of complex biological pathways.

    “We are hopeful that we’ll be able to quantify the individual steps in a metabolic pathway and be able to measure indicators of disease processes and factors important to why people differ in responses to therapeutics, to diet and other factors,” Turteltaub said.

    Graham Bench, the director of the Lab’s Center for Accelerator Mass Spectrometry, anticipates the upgrades will enable Lab researchers “to produce high-density data sets and tackle novel biomedical problems that in the past couldn’t be addressed.”

    Ted Ognibene, a chemist who has worked on AMS for 15 years and who co-developed the technique that accommodates liquid samples, also envisions new scientific work coming forth.

    two
    Ted Ognibene (left), a chemist who co-developed the technique that accommodates liquid samples for accelerator mass spectrometry, peers with biomedical scientist Mike Malfatti at the new biological AMS instrument that has been installed in the Laboratory’s biomedical building. Photo by George Kitrinos

    “We previously had the capability to detect metabolites, but now with the ability to see our results almost immediately for a fraction of the cost, it’s going to enable a lot more fundamental and new science to be done,” Ognibene said.

    Biological AMS is a technique in which carbon-14 is used as a tag to study with extreme precision and sensitivity complex biological processes, such as cancer, molecular damage, drug and toxin behavior, nutrition and other areas.

    Among the biomedical studies that will be funded through the five-year, $7.8 million National Institutes of Health grant for biological AMS work is one to try to develop a test to predict how people will respond to chemotherapeutic drugs.

    Another research project seeks to create an assay that is so sensitive that it can detect one cancer cell among one million healthy cells. If this work is successful, it could be possible to evaluate the metastasis potential of different primary human cancer cells.

    Lab biomedical scientist Mike Malfatti and two researchers - Paul Henderson, an associate professor, and Chong-Xian Pan, a medical oncologist — from the University of California, Davis Comprehensive Cancer Center, are using the AMS in a human trial with 50 patients to see how cancer patients respond or don’t respond to the chemotherapeutic drug carboplatin. This drug kills cancer cells by binding to DNA, and is toxic to rapidly dividing cells.

    The three researchers have the patients take a microdose of carboplatin — about 1/100th of a therapeutic dose — that has no toxicity or therapeutic value to evaluate how effectively the drug will bind to a person’s DNA during full dose treatment.

    Within a few days of patients receiving the microdose, the degree of drug binding is checked by blood sample, in which the DNA is isolated from white blood cells, or by tumor biopsy, in which the DNA is isolated from the tumor cells.

    The carboplatin dose is prepared with a carbon-14 tag. The DNA sample is analyzed using AMS and the instrument quantifies the carbon-14 level, with a high level of carbon-14 indicating a high level of drug binding to the DNA.

    “A high degree of binding indicates that you have a high probability of a favorable response to the drug,” Malfatti said. “Conversely, a low degree of binding means it is likely the person’s body won’t respond to the treatment.

    “If we can identify which people will respond to which chemotherapeutic drug, we can tailor the treatment to the individual.

    “There are many negative side effects associated with chemotherapy, such as nausea, loss of appetite, loss of hair and even death. We don’t want someone to receive chemotherapy that’s not going to help them, yet leave them with these negative side effects,” he added.

    Malfatti, Henderson and Pan also are using the AMS in pre-clinical studies to investigate the resistance or receptivity of other commonly used chemotherapeutic agents such as cisplatin, oxaliplatin and gemcitabine.

    Another team of researchers, led by Gaby Loots, a Lab biomedical scientist and an associate professor at the University of California, Merced, wants to use AMS to measure cancer cells labeled with carbon-14 to study the cancer cells’ migration to healthy tissues to determine how likely they are to form metastatic tumors.

    While today’s standard methods can detect tumors that are comprised of thousands of cells, the team would like to develop an assay with a thousand-fold better resolution – to detect one cancer cell among one million healthy ones.

    “The sensitivity of AMS allows us to develop more accurate, quantitative assays with single-cell resolution. Is the cancer completely gone, or do we see one cell worth of cancer DNA?” Loots noted.

    Some of the questions the team would like to answer are: 1) why certain cells metastasize? 2) how do cells metastasize? 3) what new methods can be developed to prevent metastasis?

    “Tumors shed cells all the time that enter our circulation. We would like to find ways to prevent the circulating tumor cells from forming metastatic tumors,” Loots continued.

    As a part of their research, the team members hope to determine whether cancer cells with stem-cell-like properties form more aggressive tumors.

    “We’re going to separate the cancer cells into stem-cell-like and non-stem-cell-like populations and seek to determine if they behave differently,” said Loots, who is working with fellow Lab biomedical scientists Nick Hum and Nicole Collette.

    See the full article here.

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  • richardmitnick 6:09 pm on October 16, 2014 Permalink | Reply
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    From Johns Hopkins: “Chemical derived from broccoli sprouts shows promise in treating autism” 

    Johns Hopkins
    Johns Hopkins University

    October 13, 2014
    Catherine Kolf

    Many trial participants who received daily dose of sulforaphane show improvements in social interaction, verbal communication, researchers say

    Results of a small clinical trial suggest that a chemical derived from broccoli sprouts—and best known for claims that it can help prevent certain cancers—may ease classic behavioral symptoms in those with autism spectrum disorders.

    bro

    The study, a joint effort by scientists at MassGeneral Hospital for Children and the Johns Hopkins University School of Medicine, involved 40 teenage boys and young men, ages 13 to 27, with moderate to severe autism.

    In a report published online in the journal Proceedings of the National Academy of Sciences, the researchers say that many of those who received a daily dose of the chemical sulforaphane experienced substantial improvements in their social interaction and verbal communication, along with decreases in repetitive, ritualistic behaviors, compared to those who received a placebo.

    “We believe that this may be preliminary evidence for the first treatment for autism that improves symptoms by apparently correcting some of the underlying cellular problems,” says Paul Talalay, a professor of pharmacology and molecular sciences at the Johns Hopkins University School of Medicine who has researched these vegetable compounds for the past 25 years.

    “We are far from being able to declare a victory over autism, but this gives us important insights into what might help,” says co-investigator Andrew Zimmerman, a professor of pediatric neurology at UMass Memorial Medical Center.

    Autism experts estimate that the group of disorders affects 1 to 2 percent of the world’s population, with a much higher incidence in boys than in girls. Its behavioral symptoms, such as poor social interaction and verbal communication, are well known and were first described 70 years ago by Leo Kanner, the founder of pediatric psychiatry at Johns Hopkins University.

    Unfortunately, the root causes of autism remain elusive, though progress has been made, Talalay says, in describing some of the biochemical and molecular abnormalities that tend to accompany the disorders. Many of these are related to the efficiency of energy generation in cells. He says that studies show that the cells of those on the autism spectrum often have high levels of oxidative stress, the buildup of harmful, unintended byproducts from the cell’s use of oxygen that can cause inflammation, damage DNA, and lead to cancer and other chronic diseases.

    In 1992, Talalay’s research group discovered that sulforaphane has some ability to bolster the body’s natural defenses against oxidative stress, inflammation, and DNA damage. In addition, the chemical later turned out to improve the body’s heat-shock response—a cascade of events used to protect cells from the stress caused by high temperatures, including those experienced when people have fever.

    Intriguingly, he says, about 50% of parents report that their children’s autistic behavior improves noticeably when they have a fever, then reverts back when the fever is gone. In 2007, Zimmerman, a principal collaborator in the current study, tested this anecdotal trend clinically and found it to be true, though a mechanism for the fever effect was not identified.

    Because fevers, like sulforaphane, initiate the body’s heat-shock response, Zimmerman and Talalay wondered if sulforaphane could cause the same temporary improvement in autism that fevers do. The current study was designed to find out.

    Before the start of the trial, the patients’ caregivers and physicians filled out three standard behavioral assessments: the Aberrant Behavior Checklist (ABC), the Social Responsiveness Scale (SRS), and the Clinical Global Impressions-Improvement scale (CGI-I). The assessments measure sensory sensitivities, ability to relate to others, verbal communication skills, social interactions, and other behaviors related to autism.

    Twenty-six of the subjects were randomly selected to receive, based on their weight, 9 to 27 milligrams of sulforaphane daily, and 14 received placebos. Behavioral assessments were again completed at four, 10, and 18 weeks while treatment continued. A final assessment was completed for most of the participants four weeks after the treatment had stopped.

    Most of those who responded to sulforaphane showed significant improvements by the first measurement at four weeks and continued to improve during the rest of the treatment. After 18 weeks of treatment, the average ABC and SRS scores of those who received sulforaphane had decreased 34 and 17 percent, respectively, with improvements in bouts of irritability, lethargy, repetitive movements, hyperactivity, awareness, communication, motivation, and mannerisms.

    After 18 weeks of treatment, according to the CGI-I scale, sulforaphane recipients experienced noticeable improvements in social interaction (46%), aberrant behaviors (54%), and verbal communication (42%).

    Talalay notes that the scores of those who took sulforaphane trended back toward their original values after they stopped taking the chemical, just like what happens to those who experience improvements during a fever. “It seems like sulforaphane is temporarily helping cells to cope with their handicaps,” he says.

    Zimmerman adds that before they learned which subjects got the sulforaphane or placebo, the impressions of the clinical team—including parents—were that 13 of the participants noticeably improved. For example, some treated subjects looked them in the eye and shook their hands, which they had not done before. They found out later that all 13—half of the treatment group—had been taking sulforaphane.

    Talalay cautions that the levels of sulforaphane precursors present in different varieties of broccoli are highly variable. Furthermore, the capacity of individuals to convert these precursors to active sulforaphane also varies greatly. It would be very difficult to achieve the levels of sulforaphane used in this study by eating large amounts of broccoli or other cruciferous vegetables, he notes.

    See the full article here.

    Johns Hopkins Campus

    The Johns Hopkins University opened in 1876, with the inauguration of its first president, Daniel Coit Gilman. “What are we aiming at?” Gilman asked in his installation address. “The encouragement of research … and the advancement of individual scholars, who by their excellence will advance the sciences they pursue, and the society where they dwell.”

    The mission laid out by Gilman remains the university’s mission today, summed up in a simple but powerful restatement of Gilman’s own words: “Knowledge for the world.”

    What Gilman created was a research university, dedicated to advancing both students’ knowledge and the state of human knowledge through research and scholarship. Gilman believed that teaching and research are interdependent, that success in one depends on success in the other. A modern university, he believed, must do both well. The realization of Gilman’s philosophy at Johns Hopkins, and at other institutions that later attracted Johns Hopkins-trained scholars, revolutionized higher education in America, leading to the research university system as it exists today.

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  • richardmitnick 5:55 pm on October 16, 2014 Permalink | Reply
    Tags: Applied Research & Technology, , , ,   

    From BNL: “Scientists Map Key Moment in Assembly of DNA-Splitting Molecular Machine” 

    Brookhaven Lab

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

    The proteins that drive DNA replication—the force behind cellular growth and reproduction—are some of the most complex machines on Earth. The multistep replication process involves hundreds of atomic-scale moving parts that rapidly interact and transform. Mapping that dense molecular machinery is one of the most promising and challenging frontiers in medicine and biology.

    Now, scientists have pinpointed crucial steps in the beginning of the replication process, including surprising structural details about the enzyme that “unzips” and splits the DNA double helix so the two halves can serve as templates for DNA duplication.

    The research combined electron microscopy, perfectly distilled proteins, and a method of chemical freezing to isolate specific moments at the start of replication. The study—authored by scientists from the U.S. Department of Energy’s Brookhaven National Laboratory, Stony Brook University, Cold Spring Harbor Laboratory, and Imperial College, London—published on Oct. 15, 2014, in the journal Genes and Development.

    “The genesis of the DNA-unwinding machinery is wonderfully complex and surprising,” said study coauthor Huilin Li, a biologist at Brookhaven Lab and Stony Brook University. “Seeing this helicase enzyme prepare to surround and unwind the DNA at the molecular level helps us understand the most fundamental process of life and how that process might go wrong. Errors in copying DNA are found in certain cancers, and this work could one day help develop new treatment methods that stall or break dangerous runaway machinery.”

    The research picks up where two previous studies by Li and colleagues left off. They first determined the structure of the “Origin Recognition Complex” (ORC), a protein that identifies and attaches to specific DNA sites to initiate the entire replication process. The second study revealed how the ORC recruits, cracks open, and installs a crucial ring-shaped protein structure (Mcm2-7) that lies at the core of the helicase enzyme.

    But DNA replication is a bi-directional process with two helicases moving in opposite directions. The key question, then, was how does a second helicase core get recruited and loaded onto the DNA in the opposite orientation of the first?

    dr
    Three-dimensional model (based on electron microscopy data) of the double-ring structure loaded onto a DNA helix.

    “To our surprise, we found an intermediate structure with one ORC binding two rings,” said Brookhaven Lab biologist and lead author Jingchuan Sun. “This discovery suggests that a single ORC, rather than the commonly believed two-ORC system, loads both helicase rings.”

    One step further along, the researchers also determined the molecular architecture of the final double-ring structure left behind after the ORC leaves the system, offering a number of key biological insights.

    “We now have clues to how that double-ring structure stably lingers until the cell enters the DNA-synthesis phase much later on in replication,” said study coauthor Christian Speck of Imperial College, London. “This study revealed key regulatory principles that explain how the helicase activity is initially suppressed and then becomes reactivated to begin its work splitting the DNA.”

    three
    Precision methods, close collaboration
    Collaborating scientists and study coauthors Zuanning Yuan of Stony Brook University (standing), Huilin Li of Stony Brook and Brookhaven Lab (seated, back), and Jingchuan Sun of Brookhaven Lab (seated, front) examining protein structures.

    Examining these fleeting molecular structures required mastery of biology, chemistry, and electron microscopy techniques.

    “This three-way collaboration took advantage of each lab’s long standing collaboration and expertise,” said study coauthor Bruce Stillman of Cold Spring Harbor. “Imperial College and Cold Spring Harbor handled the challenging material preparation and functional characterization, while Brookhaven and Stony Brook led the sophisticated molecular imaging and three-dimensional image reconstruction.”

    The researchers used proteins from baker’s yeast—a model organism for the more complex systems found in animals. The scientists isolated the protein mechanisms involved in replication and removed structures that might otherwise complicate the images.

    Once the isolated proteins were mixed with DNA, the scientists injected chemicals to “freeze” the binding and recruitment process at intervals of 2, 7, and 30 minutes.

    They then used an electron microscope at Brookhaven to pin down the exact structures at each targeted moment in a kind of molecular time-lapse. Rather than the light used in a traditional microscope, this technique uses focused beams of electrons to illuminate a sample and form images with atomic resolution. The instrument produces a large number of two-dimensional electron beam images, which a computer then reconstructs into three-dimensional structure.

    “This technique is ideal because we’re imaging relatively massive proteins here,” Li said. “A typical protein contains three hundred amino acids, but these DNA replication mechanisms consist of tens of thousands of amino acids. The entire structure is about 20-nanometers across, compared to 4 nanometers for an average protein.”

    Unraveling the DNA processes at the most fundamental level, the focus of this team’s work, could have far-reaching implications.

    “The structural knowledge may help others engineer small molecules that inhibit DNA replication at specific moments, leading to new disease prevention or treatment techniques,” Li said.

    Additional collaborators on this research include Alejandra Fernandez, Alberto Riera, and Silvia Tognetti of the MRC Clinical Science Centre of Imperial College, London; and Zuanning Yuan of Stony Brook University.

    The research was funded by the National Institutes of Health (GM45436, GM74985) and the United Kingdom Medical Research Council.

    See the full article here.

    BNL Campus

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world.Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
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  • richardmitnick 4:28 pm on October 16, 2014 Permalink | Reply
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    From WCG: “Project Launch: Uncovering Genome Mysteries” 

    16 Oct 2014
    Summary
    To kick off World Community Grid’s 10th anniversary celebrations, we’re launching Uncovering Genome Mysteries to compare hundreds of millions of genes from many organisms that have never been studied before, helping scientists unearth some of the hidden superpowers of the natural world.

    From the realization that the Penicillium fungus kills germs, to the discovery of bacteria that eat oil spills and the identification of aspirin in the willow tree bark – a better understanding of the natural world has resulted in many improvements to human health, welfare, agriculture and industry.

    diver
    Diver collecting microbial samples from Australian seaweeds for Uncovering Genome Mysteries

    Our understanding of life on earth has grown enormously since the advent of genetic research. But the vast majority of life on this planet remains unstudied or unknown, because it’s microscopic, easy to overlook, and hard to study. Nevertheless, we know that tiny, diverse organisms are continually evolving in order to survive and thrive in the most extreme conditions. The study of these organisms can provide valuable insights on how to deal with some of the most pressing problems that human society faces, such as drug-resistant pathogens, pollution, and energy shortages.

    Inexpensive, rapid DNA sequencing technologies have enabled scientists to decode the genes of many organisms that previously received little attention, or were entirely unknown to science. However, making sense of all that genomic information is an enormous task. The first step is to compare unstudied genes to others that are already better understood. Similarities between genes point to similarities in function, and by making a large number of these comparisons, scientists can begin to sort out what each organism is and what it can do.

    In Uncovering Genome Mysteries, World Community Grid volunteers will run approximately 20 quadrillion comparisons to identify similarities between genes in a wide variety of organisms, including microorganisms found on seaweeds from Australian coastlines and in the Amazon River. This database of similarities will help researchers understand the diversity and capabilities that are hidden in the world all around us. For more on the project’s aims and methods, see here.

    Once published, these results should help scientists with the following goals:

    Discovering new protein functions and augmenting knowledge about biochemical processes in general
    Identifying how organisms interact with each other and the environment
    Documenting the current baseline microbial diversity, allowing a better understanding of how microorganisms change under environmental stresses, such as climate change
    Understanding and modeling complex microbial systems

    In addition, a better understanding of these organisms will likely be useful in developing new medicines, harnessing new sources of renewable energy, improving nutrition, cleaning the environment, creating green industrial processes and many other advances.

    The timing of this project launch is a perfect way to kick off celebrations of another important achievement – World Community Grid’s 10th anniversary. There’s much to celebrate and reflect upon from the past decade’s work, but it’s equally important to continue pushing forward and making new scientific discoveries. With your help – and the help of your colleagues and friends – we can continue to expand our global network of volunteers and achieve another 10 years of success. Here’s to another decade of discovery!

    To contribute to Uncovering Genome Mysteries, go to your My Projects page and make sure the box for this new project is checked.

    Please visit the following pages to learn more:

    Uncovering Genome Mysteries project overview
    Frequently Asked Questions

    See the full article here.

    World Community Grid (WCG) brings people together from across the globe to create the largest non-profit computing grid benefiting humanity. It does this by pooling surplus computer processing power. We believe that innovation combined with visionary scientific research and large-scale volunteerism can help make the planet smarter. Our success depends on like-minded individuals – like you.”

    WCG projects run on BOINC software from UC Berkeley.

    BOINC is a leader in the field(s) of Distributed Computing, Grid Computing and Citizen Cyberscience.BOINC is more properly the Berkeley Open Infrastructure for Network Computing.

    CAN ONE PERSON MAKE A DIFFERENCE? YOU BETCHA!!

    “Download and install secure, free software that captures your computer’s spare power when it is on, but idle. You will then be a World Community Grid volunteer. It’s that simple!” You can download the software at either WCG or BOINC.

    Please visit the project pages-

    Say No to Schistosoma

    GO Fight Against Malaria

    Drug Search for Leishmaniasis

    Computing for Clean Water

    The Clean Energy Project

    Discovering Dengue Drugs – Together

    Help Cure Muscular Dystrophy

    Help Fight Childhood Cancer

    Help Conquer Cancer

    Human Proteome Folding

    FightAIDS@Home

    World Community Grid is a social initiative of IBM Corporation
    IBM Corporation
    ibm

    IBM – Smarter Planet
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  • richardmitnick 4:12 pm on October 16, 2014 Permalink | Reply
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    From Caltech: “Improving The View Through Tissues and Organs” 

    Caltech Logo
    Caltech

    10/16/2014
    Kimm Fesenmaier

    This summer, several undergraduate students at Caltech had the opportunity to help optimize a promising technique that can make tissues and organs—even entire organisms—transparent for study. As part of the Summer Undergraduate Research Fellowship (SURF) program, these students worked in the lab of Assistant Professor of Biology Viviana Gradinaru, where researchers are developing such so-called clearing techniques that make it possible to peer straight through normally opaque tissues rather than seeing them only as thinly sectioned slices that have been pieced back together.

    tissue
    Credit: iStock

    Gradinaru’s group recently published a paper in the journal Cell describing a new approach to tissue clearing. The method they have created builds on a technique called CLARITY that Gradinaru helped develop while she was a research associate at Stanford. CLARITY allowed researchers to, for the first time, create a transparent whole-brain specimen that could then be imaged with its structural and genetic information intact.

    CLARITY was specifically developed for studying the brain. But the new approach developed in Gradinaru’s lab, which the team has dubbed PARS (perfusion-assisted agent release in situ), can also clear other organs, such as the kidney, as well as tissue samples, such as tumor biopsies. It can even be applied to entire organisms.

    Like CLARITY, PARS involves removing the light-scattering lipids in the tissue to make samples transparent without losing the structural integrity that lipids typically provide. First the sample is infused with acrylamide monomers that are then polymerized into a hydrogel that provides structural support. Next, this tissue–hydrogel hybrid is immersed in a detergent that removes the lipids. Then the sample can be stained, often with antibodies that specifically mark cells of interest, and then immersed in RIMS (refractive index matching solution) for imaging using various optical techniques such as confocal or lightsheet microscopy.

    Over the summer, Sam Wie, a junior biology major at Caltech, spent 10 weeks in the Gradinaru lab working to find a polymer that would perform better than acrylamide, which has been used in the CLARITY hydrogel. “One of the limitations of CLARITY is that when you put the hydrogel tissue into the detergent, the higher solute concentration in the tissue causes liquid to rush into the cell. That causes the sample to swell, which could potentially damage the structure of the tissue,” Wie explains. “So I tried different polymers to try to limit that swelling.”

    Wie was able to identify a polymer that produces, over a similar amount of time, about one-sixth of the swelling in the tissue.

    “The SURF experience has been very rewarding,” Wie says. “I’ve learned a lot of new techniques, and it’s really exciting to be part of, and to try to improve, CLARITY, a method that will probably change the way that we image tissues from now on.”

    At another bench in Gradinaru’s lab, sophomore bioengineering major Andy Kim spent the summer focusing on a different aspect of the PARS technique. While antibodies have been the most common markers used to tag cells of interest within cleared tissues, they are too large for some studies—for example, those that aim to image deeper parts of the brain, requiring them to cross the blood–brain barrier. Kim’s project involved identifying smaller proteins, such as nanobodies, which target and bind to specific parts of proteins in tissues.

    “While PARS is a huge improvement over CLARITY, using antibodies to stain is very expensive,” Kim says. “However, some of these nanobodies can be produced easily, so if we can get them to work, it would not only help image the interior of the brain, it would also be a lot less costly.”

    During his SURF, Kim worked with others in the lab to identify about 30 of these smaller candidate binding proteins and tested them on PARS-cleared samples.

    While Wie and Kim worked on improving the PARS technique itself, Donghun Ryu, a third SURFer in Gradinaru’s lab, investigated different methods for imaging the cleared samples. Ryu is a senior electrical engineering and computer science major at the Gwangju Institute of Science and Technology (GIST) in the Republic of Korea.

    Last summer Ryu completed a SURF as part of the Caltech–GIST Summer Undergraduate Research Exchange Program in the lab of Changhuei Yang, professor of electrical engineering, bioengineering, and medical engineering at Caltech. While completing that project, Ryu became interested in optogenetics, the use of light to control genes. Since optogenetics is one of Gradinaru’s specialties, Yang suggested that he try a SURF in Gradinaru’s lab.

    This summer, Ryu was able to work with both Yang and Gradinaru, investigating a technique called Talbot microscopy to see whether it would be better for imaging thick, cleared tissues than more common techniques. Ryu was able to work on the optical system in Yang’s lab while testing the samples cleared in Gradinaru’s lab.

    “It was a wonderful experience,” Ryu says. “It was special to have the opportunity to work for two labs this summer. I remember one day when I had a meeting with both Professor Yang and Professor Gradinaru; it was really amazing to get to meet with two Caltech professors.”

    Gradinaru says that the SURF projects provided a learning opportunity not only for the participating students but also for her lab. “For example,” she says, “Ryu strengthened the collaboration that we have with the Yang group for the BRAIN Initiative. And my lab members benefited from the chance to serve as mentors—to see what works and what can be improved when transferring scientific knowledge. These are very important skills in addition to the experimental know-how that they master.”

    See the full article here.

    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”
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  • richardmitnick 3:51 pm on October 16, 2014 Permalink | Reply
    Tags: Applied Research & Technology, ,   

    From UC Berkeley: “Earth’s magnetic field could flip within a human lifetime” 

    UC Berkeley

    UC Berkeley

    October 14, 2014
    Robert Sanders

    Imagine the world waking up one morning to discover that all compasses pointed south instead of north.

    It’s not as bizarre as it sounds. Earth’s magnetic field has flipped – though not overnight – many times throughout the planet’s history. Its dipole magnetic field, like that of a bar magnet, remains about the same intensity for thousands to millions of years, but for incompletely known reasons it occasionally weakens and, presumably over a few thousand years, reverses direction.

    team
    Left to right, Biaggio Giaccio, Gianluca Sotilli, Courtney Sprain and Sebastien Nomade sitting next to an outcrop in the Sulmona basin of the Apennine Mountains that contains the Matuyama-Brunhes magnetic reversal. A layer of volcanic ash interbedded with the lake sediments can be seen above their heads. Sotilli and Sprain are pointing to the sediment layer in which the magnetic reversal occurred. (Photo by Paul Renne)

    Now, a new study by a team of scientists from Italy, France, Columbia University and the University of California, Berkeley, demonstrates that the last magnetic reversal 786,000 years ago actually happened very quickly, in less than 100 years – roughly a human lifetime.

    “It’s amazing how rapidly we see that reversal,” said UC Berkeley graduate student Courtney Sprain. “The paleomagnetic data are very well done. This is one of the best records we have so far of what happens during a reversal and how quickly these reversals can happen.”

    Sprain and Paul Renne, director of the Berkeley Geochronology Center and a UC Berkeley professor-in- residence of earth and planetary science, are coauthors of the study, which will be published in the November issue of Geophysical Journal International and is now available online.

    Flip could affect electrical grid, cancer rates

    The discovery comes as new evidence indicates that the intensity of Earth’s magnetic field is decreasing 10 times faster than normal, leading some geophysicists to predict a reversal within a few thousand years.

    Though a magnetic reversal is a major planet-wide event driven by convection in Earth’s iron core, there are no documented catastrophes associated with past reversals, despite much searching in the geologic and biologic record. Today, however, such a reversal could potentially wreak havoc with our electrical grid, generating currents that might take it down.

    And since Earth’s magnetic field protects life from energetic particles from the sun and cosmic rays, both of which can cause genetic mutations, a weakening or temporary loss of the field before a permanent reversal could increase cancer rates. The danger to life would be even greater if flips were preceded by long periods of unstable magnetic behavior.

    “We should be thinking more about what the biologic effects would be,” Renne said.

    Dating ash deposits from windward volcanoes

    The new finding is based on measurements of the magnetic field alignment in layers of ancient lake sediments now exposed in the Sulmona basin of the Apennine Mountains east of Rome, Italy. The lake sediments are interbedded with ash layers erupted from the Roman volcanic province, a large area of volcanoes upwind of the former lake that includes periodically erupting volcanoes near Sabatini, Vesuvius and the Alban Hills.

    two
    Leonardo Sagnotti, standing, and coauthor Giancarlo Scardia collecting a sample for paleomagnetic analysis.

    Italian researchers led by Leonardo Sagnotti of Rome’s National Institute of Geophysics and Volcanology measured the magnetic field directions frozen into the sediments as they accumulated at the bottom of the ancient lake.

    Sprain and Renne used argon-argon dating, a method widely used to determine the ages of rocks, whether they’re thousands or billions of years old, to determine the age of ash layers above and below the sediment layer recording the last reversal. These dates were confirmed by their colleague and former UC Berkeley postdoctoral fellow Sebastien Nomade of the Laboratory of Environmental and Climate Sciences in Gif-Sur-Yvette, France.

    Because the lake sediments were deposited at a high and steady rate over a 10,000-year period, the team was able to interpolate the date of the layer showing the magnetic reversal, called the Matuyama-Brunhes transition, at approximately 786,000 years ago. This date is far more precise than that from previous studies, which placed the reversal between 770,000 and 795,000 years ago.

    “What’s incredible is that you go from reverse polarity to a field that is normal with essentially nothing in between, which means it had to have happened very quickly, probably in less than 100 years,” said Renne. “We don’t know whether the next reversal will occur as suddenly as this one did, but we also don’t know that it won’t.”

    Unstable magnetic field preceded 180-degree flip

    Whether or not the new finding spells trouble for modern civilization, it likely will help researchers understand how and why Earth’s magnetic field episodically reverses polarity, Renne said.
    the polar wanderingsThe ‘north pole’ — that is, the direction of magnetic north — was reversed a million years ago. This map shows how, starting about 789,000 years ago, the north pole wandered around Antarctica for several thousand years before flipping 786,000 years ago to the orientation we know today, with the pole somewhere in the Arctic.

    The magnetic record the Italian-led team obtained shows that the sudden 180-degree flip of the field was preceded by a period of instability that spanned more than 6,000 years. The instability included two intervals of low magnetic field strength that lasted about 2,000 years each. Rapid changes in field orientations may have occurred within the first interval of low strength. The full magnetic polarity reversal – that is, the final and very rapid flip to what the field is today – happened toward the end of the most recent interval of low field strength.

    Renne is continuing his collaboration with the Italian-French team to correlate the lake record with past climate change.

    Renne and Sprain’s work at the Berkeley Geochronology Center was supported by the Ann and Gordon Getty Foundation.

    See the full article here.

    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

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