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  • richardmitnick 8:45 am on August 21, 2014 Permalink | Reply
    Tags: Advamced Photon Source - Argonne, , , , ,   

    From Astrobiology: “Scientists Detect Evidence of ‘Oceans Worth’ of Water in Earth’s Mantle” 

    Astrobiology Magazine

    Astrobiology Magazine

    Aug 21, 2014
    Andrew Williams

    Researchers have found evidence of a potential “ocean’s worth” of water deep beneath the United States.

    Although not present in a familiar form, the building blocks of water are bound up in rock located deep in the Earth’s mantle, and in quantities large enough to represent the largest water reservoir on the planet, according to the research.

    For many years, scientists have attempted to establish exactly how much water may be cycling between the Earth’s surface and interior reservoirs through the action of plate tectonics. Northwestern University geophysicist Steve Jacobsen and University of New Mexico seismologist Brandon Schmandt have found deep pockets of magma around 400 miles beneath North America — a strong indicator of the presence of H₂O stored in the crystal structure of high-pressure minerals at these depths.

    “The total H₂O content of the planet has long been among the most poorly constrained ‘geochemical parameters’ in Earth science. Our study has found evidence for widespread hydration of the mantle transition zone,” says Jacobsen.

    For at least 20 years geologists have known from laboratory experiments that the Earth’s transition zone — a rocky layer of the Earth’s mantle located between the lower mantle and upper mantle, at depths between 250 and 410 miles — can, in theory, hold about 1 percent of its total weight as H₂O, bound up in minerals called wadsleyite and ringwoodite. However, as Schmandt explains, up until now it has been difficult to figure out whether that potential water reservoir is empty, as many have suggested, or not.

    If there does turn out to be a substantial amount of H₂O in the transition zone, then recent laboratory experiments conducted by Jacobsen indicate there should be large quantities of what he calls “partial melt” in areas where mantle flows downward out of the zone. This water-rich silicate melt is molten rock that occurs at grain boundaries between solid mineral crystals and may account for about 1 percent of the volume of rocks.

    two
    Brandon Schmandt (University of New Mexico, left) and Steve Jacobsen (Northwestern University, right) combined seismic observations from the US-Array with laboratory experiments to detect dehydration melting of hydrous mantle material beneath North America at depths of 700-800 km. Credit: University of New Mexico/Northwestern University

    “Melting occurs because hydrated rocks are carried from the transition zone, where the rocks can hold lots of H₂O, downward into the lower mantle, where the rocks cannot hold as much H₂O. Melting is the way to get rid of the H₂O that won’t fit in the crystal structure present in the lower mantle,” says Jacobsen.

    He adds:

    “When a rock starts to melt, whatever H₂O is bound in the rock will go into the melt right away. So the melt would have much higher H₂O concentration than the remaining solid. We’re not sure how it got there. Maybe it’s been stuck there since early in Earth’s history or maybe it’s constantly being recycled by plate tectonics.”

    Seismic Waves

    Melt strongly affects the speed of seismic waves — the acoustic-like waves of energy that travel through the Earth’s layers as a result of an earthquake or explosion. This is because stiff rocks, like the silicate-rich ones present in the mantle, propagate seismic waves very quickly. According to Schmandt, if just a little melt — even 1 percent or less — is added between the crystal grains of such a rock it causes it to become less stiff, meaning that elastic waves propagate more slowly.

    “We were able to analyse seismic waves from earthquakes to look for melt in the mantle just beneath the transition zone,” says Schmandt.

    “What we found beneath the U.S. is consistent with partial melt being present in areas of downward flow out of the transition zone. Without the presence of H₂O, it is very difficult to explain melting at these depths. This is a good hint that the transition zone H₂O reservoir is not empty, and even if it’s only partially filled that could correspond to about the same mass of H₂O as in Earth’s oceans,” he adds.

    Jacobsen and Schmandt hope that their findings, published in the June issue of the journal Science, will help other scientists to understand how the Earth formed and what its current composition and inner workings are, as well as establish how much water is trapped in mantle rock.

    “I think we are finally seeing evidence for a whole-Earth water cycle, which may help explain the vast amount of liquid water on the surface of our habitable planet. Scientists have been looking for this missing deep water for decades,” says Jacobsen

    Mantle Rock Studies

    The study combined Schmandt’s analysis of seismic data from the USArray, a network of over 2,000 seismometers across the U.S., with Jacobsen’s laboratory experiments, in which he examined the behaviour of mantle rock under conditions designed to simulate the high pressures and temperatures present at 400 miles below the Earth’s surface.

    globe
    Schematic representation of seismometers placed in the US-Array between 2004 and 2014 and used in the study by Schmandt and Jacobsen to detect dehydration melting at the top of the lower mantle beneath North America. Image Credit: NSF-Earthscope

    The USArray is part of Earthscope, a program sponsored by National Science Foundation. Jacobsen’s experiments were conducted at two Department of Energy. user facilities, the Advanced Photon Source of Argonne National Laboratory and the National Synchrotron Light Source at Brookhaven National Laboratory.

    Argonne APS
    APS at Argonne Lab

    Brookhaven NSLS
    NSLS at Brookhaven

    Taken as a whole, their findings produced strong evidence that melting may occur about 400 miles deep in the Earth, with H₂O stored in mantle rocks, such as those containing the mineral ringwoodite, which is likely to be a dominant mineral at those depths.

    Schmandt explains that he made this discovery after carrying out seismic imaging of the boundary between the transition zone and lower mantle. He found evidence that, in areas where “sharp transitions” like melt are present, some earthquake energy had converted from a compressional, or longitudinal wave, to a shear or S-wave. The phase of the converted S-waves in areas where the mantle is flowing down and out of the transition zone indicated a significantly lower velocity than surrounding mantle. The discovery suggests that water from the Earth’s surface can be driven to such great depths by plate tectonics, eventually resulting in the partial melting of the rocks found deep in the mantle.

    “We used many seismic wave conversions to see that many areas beneath the U.S. may have some melt just beneath the transition zone. The next step was comparing these areas to the areas where mantle flow models predict downward flow out of the transition zone,” says Schmandt.

    Ringwoodite

    Schmandt and Jacobsen’s findings build on a discovery reported in March in the journal Nature in which scientists discovered a piece of the blue mineral ringwoodite inside a diamond brought up from a depth of 400 miles by a volcano in Brazil. That tiny piece of ringwoodite — the only sample we have from within the Earth — contained a surprising amount of water bound in solid form in the mineral.

    “Not only was this the first terrestrial ringwoodite ever seen — all other natural ringwoodite examples came from shocked meteorites — but the tiny inclusion of ringwoodite was also full of H₂O, to about 1.5 percent of total weight,” says Jacobsen. “This is about the maximum amount of water that we are able to put into ringwoodite in laboratory experiments.”

    Although the discovery provided direct evidence of water in the deep mantle at about 700 kilometers (434 miles) deep, the diamond sampled only one point of the mantle. Jacobsen explains that the paper expands the search to question how widespread hydration might be throughout the entire transition zone. This is important because the presence of H₂O in the large volumes of rock found at depths of between 410 to 660 kilometers (255 to 410 miles) would “significantly alter our understanding of the composition of the Earth.”

    Crystals of laboratory-grown hydrous ringwoodite, a high-pressure polymorph of olivine that is stable from about 520-660 km depth in the Earth’s mantle. The ringwoodite pictured here contains around one weight percent of H2O, similar to what was inferred in the seismic observations made by Schmandt and Jacobsen. Image Credit: Steve Jacobsen/Northwestern University

    Crystals of laboratory-grown hydrous ringwoodite, a high-pressure polymorph of olivine that is stable from about 520-660 km depth in the Earth’s mantle. The ringwoodite pictured here contains around one weight percent of H2O, similar to what was inferred in the seismic observations made by Schmandt and Jacobsen. Image Credit: Steve Jacobsen/Northwestern University

    “It would double or triple the known amount of H₂O in the bulk Earth. Just 1 to 2 percent H₂O by weight in the transition zone would be equivalent to 2 to 3 times the amount of H₂O in the oceans,” adds Jacobsen.

    Big Questions

    Looking ahead, Jacobsen admits that some big questions remain. For example, if the transition zone is full of H₂O, what does this tell us about the origin of Earth’s water? And is the presence of ringwoodite in a planet’s mantle necessary for a planet to retain enough original water to form oceans? Moreover, how is the H₂O in the transition zone connected to the surface reservoirs? Is the transition zone, if it contains a geochemical reservoir of H₂O larger than the oceans, somehow buffering the amount of liquid water on the Earth’s surface?

    “An analogy could be that of a sponge, which needs to be filled before liquid water can be supported on top. Was water in the transition zone added through plate tectonics early in Earth’s history, or did the oceans de-gas from the mantle until an equilibrium was reached between surface and interior reservoirs?” asks Jacobsen.

    Either way, the research is likely to be of strong interest to astrobiologists largely because water is often so closely linked to the formation of biological life. Remote geochemical analysis could be one way of detecting if such processes occur elsewhere in the universe, and it is likely that such analysis would involve the use of gamma-ray, neutron, and x-ray spectrometers of the type used by the NASA MESSENGER spacecraft for the remote geochemical mapping of Mercury.

    NASA Messenger satellite
    NASA Messenger

    “On other hard to reach planets it’s not practical to apply the type of seismic imaging that I used. So my guess is that geochemical analysis of volcanic rocks from other planetary bodies may be our best way to test whether volatiles are stored in the planet’s interior,” says Schmandt.

    See the full article here.

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  • richardmitnick 3:02 pm on August 16, 2014 Permalink | Reply
    Tags: Advamced Photon Source - Argonne, , , ,   

    From Argonne Lab: “New nanotech invention improves effectiveness of the ‘penicillin of cancer'” 

    News from Argonne National Laboratory

    August 13, 2014
    Jared Sagoff

    Scientists at the U.S. Department of Energy’s Argonne National Laboratory have added a new weapon to oncologists’ arsenal of anti-cancer therapies.

    By combining magnetic nanoparticles with one of the most common and effective chemotherapy drugs, Argonne researchers have created a way to deliver anti-cancer drugs directly into the nucleus of cancer cells.

    nano
    “This new method gives a way of delivering the dose of therapeutic cargo much more directly, which will enable us to have the same overall effect with a lower total dose, reducing the unpleasant and dangerous side effects of chemotherapy,” said oncologist Ezra Cohen, an author of the study.

    Researchers at Argonne’s Center for Nanoscale Materials and oncologists at the University of Chicago created nano-sized bubbles, or “micelles,” that contained two ingredients at their centers: magnetic nanoparticles of iron oxide and cisplatin, a conventional chemotherapy drug also known as “the penicillin of cancer.”

    Cisplatin works by directly blocking DNA replication within the cancer cell. However, in order to work, the cisplatin has to make it from the bloodstream through the somewhat rigid barrier of the cell membrane.

    “When someone is given a dose of chemotherapy, typically much of the drug doesn’t actually make it into the cancer cells. In addition, some cancer patients are sensitive to this drug due to impaired kidney function,” said oncologist Ezra Cohen, an author of the study. “This new method gives a way of delivering the dose of therapeutic cargo much more directly, which will enable us to have the same overall effect with a lower total dose, reducing the unpleasant and dangerous side effects of chemotherapy.”

    “This technique could potentially allow us to increase the proportion of cisplatin in cancer cells by a hundredfold, making it that much more effective a chemotherapeutic agent,” he added.

    Like the membranes of cancer cells themselves, the micelles are made up of a polymer material whose outer surfaces are hydrophilic, which means they are attracted to water, while the inner parts are hydrophobic, repelling water. “In addition, the surface of micelles can be equipped with targeting molecules capable of recognizing malignancy,” said Argonne nanoscientist Elena Rozhkova, lead author of the study.

    Rozhkova and her colleagues still needed a way to get the cisplatin into the nucleus of the cancer cell after the micelle had attached to it. To do so, they also encapsulated iron oxide nanoparticles within the micelle along with the cisplatin. These nanoparticles served as tiny “heaters” that were turned on by an applied magnetic field, which caused the micelle container to collapse and release the cisplatin.

    This was not the first time scientists had used applied nanomagnetic heat sources as a way to attack cancer cells, but the more targeted approach of the micelles allowed the researchers to use a much lower amount of heat and much less magnetic material, thereby risking less damage to healthy cells.

    In order to see the action of the nanoparticles and cisplatin as the micelle collapsed, the researchers used the Hard X-Ray Nanoprobe at Argonne’s Advanced Photon Source. “Normally, it’s difficult to see how cisplatin is delivered into organelles like the nucleus, but with this technology we can see simultaneously how the drug delivery happens, how the nanoparticles interact with the cell’s membrane and the cell’s response,” said Argonne nanoscientist Volker Rose.

    The study, entitled Efficient cisplatin pro-drug delivery visualized with sub-100 nm resolution: interfacing engineered thermosensitive magnetomicelles with a living system, appeared online in the June 6 issue of Advanced Materials Interfaces.

    The materials characterization and synthesis work was performed at the Center for Nanoscale Materials and the Advanced Photon Source, both DOE Office of Science User Facilities. The medical aspects of the research, including animal studies, were supported by the University of Chicago.

    The Center for Nanoscale Materials at Argonne National Laboratory is one of the five DOE Nanoscale Science Research Centers (NSRCs), premier national user facilities for interdisciplinary research at the nanoscale, supported by the DOE Office of Science. Together the NSRCs comprise a suite of complementary facilities that provide researchers with state-of-the-art capabilities to fabricate, process, characterize and model nanoscale materials, and constitute the largest infrastructure investment of the National Nanotechnology Initiative. The NSRCs are located at DOE’s Argonne, Brookhaven, Lawrence Berkeley, Oak Ridge and Sandia and Los Alamos National Laboratories. For more information about the DOE NSRCs, please visit the Office of Science website.

    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

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  • richardmitnick 3:33 pm on August 13, 2014 Permalink | Reply
    Tags: Advamced Photon Source - Argonne, , Bone Density, Osteoporosis,   

    From APS at Argonne Lab: “Revealing a Novel Mode of Action for an Osteoporosis Drug” 

    News APS at Argonne National Laboratory

    August 13, 2014

    Emma Nichols

    Raloxifene is a U.S. Food and Drug Administration (FDA)-approved treatment for decreasing fracture risk in osteoporosis. While raloxifene is as effective at reducing fracture risk as other current treatments, this works only partially by suppressing bone loss. With the use of wide- and small-angle x-ray scattering (WAXS and SAXS, respectively), researchers carried out experiments at the U.S. Department of Energy’s (DOE’s) Advanced Photon Source (APS) at Argonne National Laboratory that revealed an additional mechanism underlying raloxifene action, providing an explanation for how this drug can achieve equivalent clinical benefit.

    bench
    Schematic of mechanical testing apparatus utilized during collection of WAXS diffraction data at the APS. Bone beams were subjected to 4-point bending, and after each displacement of 20 mm (black arrow), 20 x-ray scattering measurements were taken (red dashed line). Diffraction patterns collected by the detector (indicated) allow for quantification of strain experienced by hydroxyapatite crystals and mineralized collagen within the bone. Adapted from M.A. Gallant, Bone 61, 191 (2014).

    These data, together with complementary techniques, help define a novel mechanism by which raloxifene increases inherent bone toughness.

    In osteoporosis, decreased bone density increases the risk of fracture. All current drugs for treatment of this disease act upon living cells within the bone matrix to either decrease bone resorption, a process by which the mineral components of bone are broken down and released into the bloodstream, or to increase net bone formation during remodeling, a process by which bone is also broken down but then reforms bone. In either case, treatment results in an overall increase in bone density, and therefore a reduction in fracture risk.

    While raloxifene is known to mildly suppress bone loss, “It has always been somewhat paradoxical that raloxifene suppresses bone loss less than other osteoporosis therapies, yet reduces fracture risk to about the same level,” said David B. Burr of Indiana University School of Medicine and lead author of the Bone article on this research.

    To uncover the density-independent mechanism by which raloxifene (marketed as Evista by Eli Lilly and Company) increases bone toughness, researchers in this study from the Indiana University School of Medicine; Purdue University; Indiana University–Purdue University at Indianapolis; the University of California, San Diego; Northwestern University; and Argonne National Laboratory assessed the effect of the drug on devitalized bone cleared of living cells that normally mediate resorption and remodeling.

    In these bone samples, raloxifene prolonged the loading that the bone could bear before fracturing, indicating that the drug was acting upon the physical properties of the bone itself. Using ultra-short-echo-time nuclear magnetic resonance, researchers found that raloxifene-mediated water retention within the bone matrix is associated with the observed increase in toughness.

    In order to elucidate the mechanism underlying this association, researchers collected WAXS and SAXS diffraction patterns of carbonated hydroxyapatite crystals (cAp), the mineral component of bone that had been subjected to four-point bending. These data, collected at the X-ray Science Division 1-ID x-ray beamline at the Argonne APS, a Department of Energy user facility, allowed the researchers to measure mechanical strains on cAp crystals at a resolution of 1μm and showed that raloxifene increased the amount of physical deformation, or strain, that occurred at the collagen-mineral interface before fracture.

    This increased strain between cAp and collagen reduces stresses and may be caused by water-mediated slipping between these components at their interface, increasing the amount of energy the bone can absorb prior to fracture.

    “The x-ray diffraction data,” Burr said, “allowed us to explain the mechanism by which increases in bound water would improve the fracture properties of bone.”

    According to Burr, this work uncovers an entirely novel mechanism of action for raloxifene and “paves the way for a new class of drugs to treat osteoporosis, therapies that do not act by altering cellular activity or bone remodeling, but act by directly changing the physical properties of the bone matrix constituents.”

    See the full article here.

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

    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.

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  • richardmitnick 2:43 pm on January 23, 2013 Permalink | Reply
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    From Argonne: “Modifying Proteins to Combat Disease” 

    News from Argonne National Laboratory

    JANUARY 22, 2013
    Mona Mort

    “Transmitting from one generation to the next the genetic message encoded in DNA is a well-understood concept in biology. There is now increasing awareness that chemical modifications of DNA and associated proteins are also transmitted across generations, and these changes are critical in determining the way the genetic message is read. Detailed understanding of the structures of the proteins that effect these changes is therefore highly coveted information. Thanks to the efforts of a research team from Eli Lilly and Company, with the help of the Lilly Research Laboratories Collaborative Access Team (LRL-CAT) beamline 31-ID at the U.S. Department of Energy Office of Science’s Advanced Photon Source, the structure of an important methylation enzyme is now known. The results of this research can be utilized to provide new direction and focus in the race to create drugs to combat disease, especially cancer.

    mty
    Structure of the human PRMT5:MEP50 hetero-octameric complex bound to a substrate peptide and a cofactor analog. Cartoon representations of the PRMT5 monomers are colored blue, green, wheat, and yellow, while the MEP50 molecules are in red. Highlighted in stick representation are the substrate peptide derived from histone H3 in magenta, and the cofactor analog in orange. No image credit.

    The team focused on PRMT5, which had been previously shown to be part of a complex of partner proteins that help regulate its function and specificity. Because enhanced levels of PRMT5 have been observed in various types of cancer, it is a focus of anti-cancer drug research.”

    This can be important. Everyone hates Cancer. See the full article here.

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

    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.

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  • richardmitnick 12:10 pm on January 16, 2013 Permalink | Reply
    Tags: Advamced Photon Source - Argonne, , , , ,   

    From Argonne Lab: “Nanoscale ‘Goldilocks’ phenomenon could improve biofuel production” 

    News from Argonne National Laboratory

    January 15, 2013
    Jared Sagoff

    In a case of the Goldilocks story retold at the molecular level, scientists at the U.S. Department of Energy’s (DOE) Argonne National Laboratory and Northwestern University have discovered a new path to the development of more stable and efficient catalysts.

    molecule
    A computer graphic showing a fructose molecule (white, gray and red chain-like structure) within a zirconium oxide nanobowl (at center). Other nanobowls in the array are unoccupied. The red atoms are surface oxygen and the blue atoms are zirconium. Larry Curtiss, Argonne National Laboratory

    Catalysts are vitally important substances that enable the production of everything from petroleum to soap.

    The research team sought to create nanobowls – nanosized bowl shapes that allow inorganic catalysts to operate selectively on particular molecules.

    ‘Nanobowls are intended to mimic the selective enzymes found in nature, said Argonne chemist Jeffrey Elam. ‘We can tailor the nanobowl size and shape to accept certain molecules and reject others.’

    According to Elam, the design’s effectiveness correlates with the size and depth of the bowl; if the bowl is too large or shallow, practically any molecule can access the catalyst, which can lead to uncontrolled and often undesirable side reactions. Likewise, if the bowl is too small or deep, even the intended molecule will not fit into the bowl. However, if the nanobowl structure is “just right,” only the intended molecule will reach the catalyst and react.

    Elam and his colleagues also used the 12ID-C X-ray beamline at the laboratory’s Advanced Photon Source to characterize the structure of the nanobowls.
    The work was reported in the journal Nature Chemistry.

    The trick to building a nanobowl with a specific shape and depth is to use a nano-sized template. In the first proof-of-concept nanobowl experiments, bulky organic molecules called calixarenes were used as the template. They were grafted onto a titanium dioxide surface that served as both the catalyst and the ‘table’ for the nanobowl to rest on. Next, the walls of the bowl were built around the template, one atomic layer at a time, using atomic layer deposition (ALD), a technology borrowed from the semiconductor industry. Once the scientists grew the nanobowl to the proper height, they burned away the organic template, leaving behind a cavity with the same shape.”

    See the full article, complete with a list of collaborators here.

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


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  • richardmitnick 1:35 pm on January 8, 2013 Permalink | Reply
    Tags: Advamced Photon Source - Argonne, , , ,   

    From Argonne: “Clues about Rheumatoid Arthritis Damage” 

    Argonne National Laboratory

    JANUARY 7, 2013
    Emma Hitt

    Rheumatoid arthritis (RA) is a progressively incapacitating and devastating disease that involves destruction of many tissues within the body, but especially the joint tissues. About 1% of the world population is affected by RA, and the disease strikes women up to five times as often as men. RA is characterized by a highly variable disease course. Some of the afflicted will have mild and transient symptoms, but most will experience ongoing disease for the rest of their lives. Many different types of treatments can alleviate symptoms and/or modify the disease process; however, there is no known cure for rheumatoid arthritis and a need exists for therapies that will halt the underlying disease processes.

    hand
    A hand affected by rheumatoid arthritis (Wikipedia)

    Utilizing x-ray crystallography at an Advanced Photon Source x-ray beamline, researchers with the Illinois Institute of Technology were able to view the actions of an antibody targeted toward the proteoglycan biglycan — one of a group of polysaccharide-protein conjugates present in connective tissue and cartilage — that may help illustrate the underlying pathology of RA.

    The role of x-ray crystallography was especially central to their work because the researchers were able to view the structure of antibody disrupted tissue without concern that sample preparation had introduced artifacts. The new findings pave the way for further studies; a greater understanding of the destructive process in RA may help in developing therapies that could ultimately prevent or delay joint disruption and help treat millions of patients with RA. The findings in part are based on x-ray diffraction data collected at the Biophysics Collaborative Access Team (Bio-CAT) 18-ID beamline at the Argonne Advanced Photon Source.”

    xray
    X-ray crystallography can locate every atom in a zeolite, an aluminosilicate with many important applications, such as water purification.

    See the full article here.

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


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  • richardmitnick 6:57 am on November 22, 2011 Permalink | Reply
    Tags: Advamced Photon Source - Argonne, , ,   

    From Argonne Labs: “Materials scientists watch electrons “melt”” 

    News from Argonne National Laboratory

    November 21, 2011
    Jared Sagoff

    “When a skier rushes down a ski slope or a skater glides across an ice rink, a very thin melted layer of liquid water forms on the surface of the ice crystals, which allows for a smooth glide instead of a rough skid. In a recent experiment, scientists have discovered that the interface between the surface and bulk electronic structures of certain crystalline materials can act in much the same way.

    Materials scientists often face the challenge of finding ways to move electrons across interfaces and through a material, according to John Mitchell, a chemist at the U.S. Department of Energy’s Argonne National Laboratory. However, the organization of the crystalline surface of a material does not always correlate with the organization of the electronic states below. In fact, in the boundary layer between the surface and the bulk can be quite rough.

    ‘You can think about the fidelity of an interface chemically—how well the atoms are arranged, or how neatly and properly they’re distributed,’ Mitchell said. ‘Below that, however, there’s a second level of organization, which is electronic fidelity.’

    While the crystal structure of the material can look nearly perfectly organized over large length scales, researchers at Argonne and Brookhaven National Laboratory showed a dividing line of ‘roughness’ between the crystal surface and the bulk. ‘The electronic structure there is not perfect; instead, it’s disturbed. That has implications for how electrons might transport within that layer or across that surface.’

    Using surface X-ray scattering techniques at Sector 6-ID of Argonne’s Advanced Photon Source, the research team studied the electronic order of an oxide material just below the temperature at which it would begin to ‘melt’—that is, to become electronically disorganized—in the bulk.

     
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