Science News

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Findings may one day lead to an effective and efficient gene therapy for cancer

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New article in the FASEB Journal shows that caffeine during pregnancy affects heart development and function

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Researchers at the University of Illinois and the University of Massachusetts at Amherst have found a way to fool a bacteria’s evolutionary machinery into programming its own death. “The basic idea is for an antimicrobial to target something in a bacteria that, in order to gain immunity, would require the bacteria to kill itself through a suicide mutation,” said Gerard Wong, a professor of materials science and engineering, of physics, and of bioengineering at the U. of I. Wong is corresponding author of a paper accepted for publication in the Proceedings of the National Academy of Sciences. The paper is to be posted this week on the journal’s Web site. The researchers show that a synthetic “hole punching” antimicrobial depends on the presence of phosphoethanolamine, a cone-shaped lipid found in high concentrations within Gram-negative bacterial membranes. Although PE lipids are commandeered to kill the bacteria, without the lipids the bacteria would die, also. “It’s a Catch-22,” Wong said. “Some mutations bacteria can tolerate, and some mutations they cannot tolerate. In this case, the bacteria would have to go through a mutation that would kill it, in order to be immune to these antimicrobials.” In their work, the researchers compared the survival of the bacterium Escherichia coli with that of a mutant strain of E. coli, which lacked PE lipids in its membrane. The fragile PE-deficient mutant strain out-survived the normal, healthy bacteria, when exposed to a “hole punching” synthetic antibiotic. However, the opposite was true when both strains were exposed to tobramycin, a conventional metabolic antibiotic that targets the bacterial ribosomal machinery rather than the membrane. The researchers first reported on compounds that functioned as molecular “hole punchers” last year in the Journal of the American Chemical Society. Their latest work further elucidates the “hole punching” mechanism. “The antimicrobial re-organizes PE lipids into holes in the membrane,” said Wong, who also is a researcher at the university’s Beckman Institute. “The perforated membranes leak, and the bacteria die.” Finding new ways to treat emerging pathogens that are more and more resistant to the best antibiotics will be increasingly important in the future, Wong said. “Now that we more fully understand how our molecular ‘hole punchers’ work, we can look for similar ways to make antimicrobials that bacteria cannot evolve immunity to.” With Wong, the paper’s co-authors include U. of I. graduate student and lead author Lihua Yang, materials science and engineering professor Dallas R. Trinkle, microbiology professor John E. Cronan Jr., and University of Massachusetts polymer science and engineering professor Gregory N. Tew, who earned a doctorate from Illinois. The work was funded by the National Science Foundation, the National Institutes of Health and the Office of Naval Research. Source: University of Illinois

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Horseradish enzyme biodegrades carbon nanotubes increasingly used in products, from electronics to plastics

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UK scientists have successfully demonstrated energy recovery on the ALICE advanced particle accelerator design, potentially paving the way for new accelerators using a fraction of the energy required under conventional methods. At 2am on 13 December, ALICE's superconducting linear accelerator accelerated electrons to 99.9% of the speed of light, creating a beam with a total energy of 11 million electron volts. This was the first time the ALICE beam had been successfully transported around the entire circuit. ALICE is operated by the Science and Technology Facilities Council (STFC) at its Daresbury Laboratory in Cheshire. It is a world-class R&D prototype designed to open the way for advances in a broad range of exciting accelerator science applications. ALICE is the first accelerator in Europe to use the energy recovery process which captures and re-uses the initial beam energy after each circuit. At the end of the circuit, rather than throwing out the used beam of high-energy electrons, its energy is extracted for continued use before being safely discarded at an extremely low energy. Susan Smith, Head of the Accelerator Physics Group at STFC Daresbury Laboratory said: "Energy recovery means a massive saving of power or alternatively, for the same power usage, light sources and colliders of unprecedented power and intensity. The ALICE team have been working tremendously hard to demonstrate energy recovery and when we did this in the small hours of Saturday morning, it felt like Christmas had come early." Dr Smith said the milestone was important but more work was required to fully validate the design. "We have proven energy recovery, but not yet quantified it. Once fully commissioned ALICE will accelerate to 35 million volts, electrons will be sent round the accelerator at 99.99% of the speed of light and 99.9% of the power at the final accelerator stage will be recovered, making the power sources for the acceleration drastically smaller and cheaper and therefore economically viable," she said. Professor Keith Mason, Chief Executive of STFC, said: "This is an impressive and significant step forward for ALICE. In itself, the concept of energy recovery is not new, but the application of this technique in combination with advanced accelerator technologies, such as super-conducting cavities, has exciting prospects for the future of next generation light sources and particle colliders." Source : Science and Technology Facilities Council

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Research by Dr. Jeremy Mao and Colleagues Uses Stem Cell Combination that Promotes Vascularization in Bone and other Tissues

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Columbia University Medical Center and NewYork-Presbyterian Hospital
Lead National Trial of New Therapeutic Technology

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CU-Boulder findings should help satellite tracking, communication forecasting

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Solar flares are the most powerful explosions in the solar system. Packing a punch equal to a hundred million hydrogen bombs, they obliterate everything in their immediate vicinity. Not a single atom should remain intact. At least that’s how it’s supposed to work. "We’ve detected a stream of perfectly intact hydrogen atoms shooting out of an X-class solar flare," says Richard Mewaldt of the California Institute of Technology. "What a surprise! If we can understand how these atoms were produced, we'll be that much closer to understanding solar flares." The event occurred on Dec. 5, 2006. A large sunspot rounded the sun’s eastern limb and with little warning it exploded. On the "Richter scale" of flares, which ranks X1 as a big event, the blast registered X9, making it one of the strongest flares of the past 30 years. NASA managers braced themselves. Such a ferocious blast usually produces a blizzard of high-energy particles dangerous to both satellites and astronauts. An hour later they arrived, but they were not the particles researchers expected. NASA’s twin Solar TErrestrial RElations Observatory (STEREO) spacecraft made the discovery: "It was a burst of hydrogen atoms," says Mewaldt. No other elements were present, not even helium (the sun’s second-most abundant atomic species). Pure hydrogen streamed past the spacecraft for a full 90 minutes." http://www.nasa.gov/images/content/296967main_flare_sxi2_226.jpg The X9-class solar flare of Dec. 5, 2006, observed by the Solar X-Ray Imager aboard NOAA's GOES-13 satellite Next came 30 minutes of quiet. The burst subsided and STEREO’s particle counters returned to low levels. The event seemed to be over when a second wave of particles enveloped the spacecraft. These were the "broken atoms" flares are supposed to produce—protons and heavier ions such as helium, oxygen and iron. "Better late than never," he says. At first, this unprecedented sequence of events baffled scientists, but now Mewaldt and colleagues believe they’re getting to the bottom of the mystery. First, how did the hydrogen atoms resist destruction? "They didn’t," says Mewaldt. "We believe they began their journey to Earth in pieces, as protons and electrons. Before they escaped the sun’s atmosphere, however, some of the protons captured an electron, forming intact hydrogen atoms. The atoms left the sun in a fast, straight shot before they could be broken apart again." (For experts: The team believes the electrons were recaptured by some combination of radiative recombination and charge exchange.) Second, what delayed the ions? "Simple," says Mewaldt. "Ions are electrically charged and they feel the sun’s magnetic field. Solar magnetism deflects ions and slows their progress to Earth. Hydrogen atoms, on the other hand, are electrically neutral. They can shoot straight out of the sun without magnetic interference." http://www.nasa.gov/images/content/296970main_nassr1_226.jpg Sunspot 930, the source of the powerful X9-flare on Dec. 5, 2006 Imagine two runners dashing for the finish line. One (the ion) is forced to run in a zig-zag pattern with zigs and zags as wide as the orbit of Mars. The other (the hydrogen atom) runs in a straight line. Who’s going to win? "The hydrogen atoms reached Earth almost two hours before the ions," says Mewaldt. Mewaldt believes that all strong flares might emit hydrogen bursts, but they simply haven’t been noticed before. He’s looking forward to more X-flares now that the two STEREO spacecraft are widely separated on nearly opposite sides of the Sun. (In 2006 they were still together near Earth.) STEREO-A and –B may be able to triangulate future bursts and pinpoint the source of the hydrogen. This would allow the team to test their ideas about the surprising phenomenon. "All we need now," he says, "is some solar activity." For more information about this research, look for the article "STEREO Observations of Energetic Neutral Atoms during the 5 December 2006 Solar Flare" by R. A. Mewaldt et al., in a future issue of the Astrophysical Journal Letters. http://www.nasa.gov/images/content/296974main_stereoconcept_226.jpg Artist's concept of one of the STEREO satellites. Source: NASA

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DURHAM, N.C.—Neuroscientists from Duke University Medical Center have discovered that older people use their brains differently than younger people when it comes to storing memories, particularly those associated with negative emotions. The study, appearing online in the January issue of Psychological Science, is a novel look at how brain connections change with age. Older adults, average age 70, and younger adults, average age 24, were shown a series of 30 photographs while their brains were imaged in a functional MRI (fMRI) machine. Some of the photos were neutral in nature and others had strong negative content such as attacking snakes, mutilated bodies and violent acts. While in the fMRI machine, the subjects looked at the photos and ranked them on a pleasantness scale. Then they completed an unexpected recall task following the fMRI scan to determine whether the brain activity that occurred while looking at the pictures could predict later memory. The results were sorted according to the numbers of negative and neutral pictures that were remembered or missed by each group. The scientists found that older adults have less connectivity between an area of the brain that generates emotions and a region involved in memory and learning. But they also found that the older adults have stronger connections with the frontal cortex, the higher thinking area of the brain that controls these lower-order parts of the brain. Young adults used more of the brain regions typically involved in emotion and recalling memories. "The younger adults were able to recall more of the negative photos," said Roberto Cabeza, Ph.D., senior author and Duke professor in the Center for Cognitive Neuroscience. If the older adults are using more thinking than feeling, "that may be one reason why older adults showed a reduction in memory for pictures with a more negative emotional content." "It wasn't surprising that older people showed a reduction in memory for negative pictures, but it was surprising that the older subjects were using a different system to help them to better encode those pictures they could remember," said lead author Peggy St. Jacques, a graduate student in the Cabeza laboratory. The emotional centers of the older subjects were as active as those of younger subjects -- it was the brain connections that differed. "If using the frontal regions to perform a memory task was always beneficial, then the young people would use that strategy, too," Cabeza said. "Each way of doing a task has some trade-offs. Older people have learned to be less affected by negative information in order to maintain their well being and emotional state – they may have sacrificed more accurate memory for a negative stimulus, so that they won't be so affected by it." "Perhaps at different stages of life, there are different brain strategies," Cabeza speculated. "Younger adults might need to keep an accurate memory for both positive and negative information in the world. Older people dwell in a world with a lot of negatives, so perhaps they have learned to reduce the impact of negative information and remember in a different way." According to Cabeza, the results of the study are consistent with a theory about emotional processes in older adults proposed by Dr. Laura Carstensen at Stanford University, an expert in cognitive processing in old age. "One thing we might do in the future is to ask subjects to try to actively regulate their emotions as they look at the pictures," St. Jacques said. "Would there be a shift in the neural networks for processing the negative pictures when we asked younger people to regulate their emotional responses? How would that affect their later recall of the negative pictures?" Source: Duke University Medical Center

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KINGSTON, R.I. – December 15, 2008 – The elevated carbon dioxide levels expected to be found in the world's oceans by 2100 will likely lead to physiological impairments of jumbo (or Humboldt) squid, according to research by two University of Rhode Island scientists. The results of a study by Brad Seibel, URI assistant professor of biological sciences, and Rui Rosa, a former URI post-doctoral student now on the faculty at the University of Lisbon, Portugal, is reported in this week's issue of the Proceedings of the National Academy of Sciences. The researchers subjected the squids (Dosidicus gigas) to elevated concentrations of CO2 equivalent to those likely to be found in the oceans in 100 years due to anthropogenic emissions. They found that the squid's routine oxygen consumption rate was reduced under these conditions, and their activity levels declined, presumably enough to have an effect on their feeding behavior. Jumbo squid are an important predator in the eastern Pacific Ocean, and they are a large component of the diet of marine mammals, seabirds and fish. According to Seibel, jumbo squid migrate between warm surface waters at night where CO2 levels are increasing and deeper waters during the daytime where oxygen levels are extremely low. "Squids suppress their metabolism during their daytime foray into hypoxia, but they recover in well-oxygenated surface waters at night," he said. "If this low oxygen layer expands into shallower waters, the squids will be forced to retreat to even shallower depths to recover. However, warming temperatures and increasing CO2 levels may prevent this. The band of habitable depths during the night may become too narrow." Carbon dioxide enters the ocean via passive diffusion from the atmosphere in a process called ocean acidification. This phenomenon has received considerable attention in recent years for its effects on calcifying organisms, such as corals and shelled mollusks, but the study by Seibel and Rosa is one of the first to show a direct physiological effect in a non-calcifying species. The scientists speculate that the squids may eventually migrate to more northern climes where lower temperatures would reduce oxygen demand and relieve them from CO2 and oxygen stress. While it is possible, they say, that the squids could adjust their physiology over time to accommodate the changing environment, jumbo squids have among the highest oxygen demands of any animal on the planet and are thus fairly constrained in how they can respond. "We believe it is the blood that is sensitive to high CO2 and low pH," Seibel said. "This sensitivity allows the squids to off-load oxygen more effectively to muscle tissues, but would prevent the squid from acquiring oxygen across the gills from seawater that is high in CO2." While many other squid and octopus species have oxygen transport systems that are equally sensitive to pH, few have such high oxygen demand coupled with large body size and low environmental oxygen. Therefore the scientists believe that their study results should not be extrapolated to other marine animals. Source: University of Rhode Island

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COLUMBUS, Ohio -- Two giant plumes of hot rock deep within the earth are linked to the plate motions that shape the continents, researchers have found. The two superplumes, one beneath Hawaii and the other beneath Africa, have likely existed for at least 200 million years, explained Wendy Panero, assistant professor of earth sciences at Ohio State University. Wendy Panero The giant plumes -- or "superpiles" as Panero calls them -- rise from the bottom of Earth's mantle, just above our planet's core. Each is larger than the continental United States. And each is surrounded by a wall of plates from Earth's crust that have sunk into the mantle. She and her colleagues reported their findings at the American Geophysical Union meeting in San Francisco. Computer models have connected the piles to the sunken former plates, but it's currently unclear which one spawned the other, Panero said. Plates sink into the mantle as part of the normal processes that shape the continents. But which came first, the piles or the plates, the researchers simply do not know. "Do these superpiles organize plate motions, or do plate motions organize the superpiles? I don't know if it's truly a chicken-or-egg kind of question, but the locations of the two piles do seem to be related to where the continents are today, and where the last supercontinent would have been 200 million years ago," she said. That supercontinent was Pangea, and its breakup eventually led to the seven continents we know today. Scientists first proposed the existence of the superpiles more than a decade ago. Earthquakes offer an opportunity to study them, since they slow the seismic waves that pass through them. Scientists combine the seismic data with what they know about Earth's interior to create computer models and learn more. Email this to a friend The presence of the superpiles and the location of subducted plates suggest that the two superpiles have likely remained fixed to the Earth's core while the rest of the mantle has churned around them for millions of years. But to date, the seismic images have created a mystery: they suggest that the superpiles have remained in the same locations, unchanged for hundreds of millions of years. "That's a problem," Panero said. "We know that the rest of the mantle is always moving. So why are the piles still there?" Hot rock constantly migrates from the base of the mantle up to the crust, she explained. Hot portions of the mantle rise, and cool portions fall. Continental plates emerge, then sink back into the earth. But the presence of the superpiles and the location of subducted plates suggest that the two superpiles have likely remained fixed to the Earth's core while the rest of the mantle has churned around them for millions of years. Unlocking this mystery is the goal of the Cooperative Institute for Deep Earth Research (CIDER) collaboration, a group of researchers from across the United States who are attempting to unite many different disciplines in the study of Earth's interior. Panero provides CIDER her expertise in mineral physics; others specialize in geodynamics, geomagnetism, seismology, and geochemistry. Together, they have assembled a new model that suggests why the two superpiles are so stable, and what they are made of. As it turns out, just a tiny difference in chemical composition can keep the superpiles in place, they found. The superpiles contain slightly more iron than the rest of the mantle; their composition likely consists of 11-13 percent iron instead of 10-12 percent. But that small change is enough to make the superpiles denser than their surroundings. "Material that is more dense is going to sink to the base of the mantle," Panero said. "It would normally spread out at that point, but in this case we have subducting plates that are coming down from above and keeping the piles contained." CIDER will continue to explore the link between the superpiles and the plates that surround them. The researchers will also work to explain the relationship between the superpiles and other mantle plumes that rise above them, which feed hotspots such as those beneath Hawaii and mid-ocean ridges. Ultimately, they hope to determine whether the superpiles may have contributed to the breakup of Pangea. Source: Ohio state university

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ANN ARBOR, Mich.--- A carbon nanotube-coated "smart yarn" that conducts electricity could be woven into soft fabrics that detect blood and monitor health, engineers at the University of Michigan have demonstrated. "Currently, smart textiles are made primarily of metallic or optical fibers. They're fragile. They're not comfortable. Metal fibers also corrode. There are problems with washing such electronic textiles. We have found a much simpler way---an elegant way---by combining two fibers, one natural and one created by nanotechnology," said Nicholas Kotov, a professor in the departments of Chemical Engineering, Materials Science and Engineering and Biomedical Engineering. Kotov and Bongsup Shim, a doctoral student in the Department of Chemical Engineering, are among the co-authors of a paper on this material currently published online in Nano Letters. To make these "e-textiles," the researchers dipped 1.5-millimeter thick cotton yarn into a solution of carbon nanotubes in water and then into a solution of a special sticky polymer in ethanol. After being dipped just a few times into both solutions and dried, the yarn was able to conduct enough power from a battery to illuminate a light-emitting diode device. "This turns out to be very easy to do," Kotov said. "After just a few repetitions of the process, this normal cotton becomes a conductive material because carbon nanotubes are conductive." The only perceptible change to the yarn is that it turned black, due to the carbon. It remained pliable and soft. In order to put this conductivity to use, the researchers added the antibody anti-albumin to the carbon nanotube solution. Anti-albumin reacts with albumin, a protein found in blood. When the researchers exposed their anti-albumin-infused smart yarn to albumin, they found that the conductivity significantly increased. Their new material is more sensitive and selective as well as more simple and durable than other electronic textiles, Kotov said. Clothing that can detect blood could be useful in high-risk professions, the researchers say. An unconscious firefighter, ambushed soldier, or police officer in an accident, for example, couldn't send a distress signal to a central command post. But the smart clothing would have this capability. Kotov says a communication device such as a mobile phone could conceivably transmit information from the clothing to a central command post. "The concept of electrically sensitive clothing made of carbon-nanotube-coated cotton is flexible in implementations and can be adapted for a variety of health monitoring tasks as well as high performance garments," Kotov said. It is conceivable that clothes made out of this material could be designed to harvest energy or store it, providing power for small electronic devices, but such developments are many years away and pose difficult challenges, the engineers say. Source: University of Michigan

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CAMBRIDGE, Mass.— MIT researchers have created a microbial ecosystem smaller than a stick of gum that sheds new light on the plankton-eat-plankton world at the bottom of the aquatic food chain. The work, reported in the January print issue of American Naturalist, may lead to better predictions of marine microbes' global-scale influence on climate. Through photosynthesis and uptake of carbon compounds, diverse planktonic marine microorganisms — too small to be seen with the naked eye — help regulate carbon flux in the oceans. Carbon flux refers to the rate at which energy and carbon are transferred from lower to higher levels of the marine food web, and it may have implications for commercial fisheries and other ocean-dependent industries. The MIT study is one of the first detailed explorations of how sea creatures so small — 500,000 can fit on the head of a pin — find food in an ocean-size environment. Besides showing that microbes' swimming and foraging is much more sophisticated and complex than previously thought, the work also indicates that organic materials may move through the oceans' microbial food web at higher-than-expected rates, via a domino effect of resource patch formation and exploitation, said co-author Justin R. Seymour, postdoctoral fellow in the MIT Department of Civil and Environmental Engineering (CEE). Using the new technology of microfluidics, Seymour and colleagues Roman Stocker, the Doherty Assistant Professor of Ocean Utilization in CEE, and MIT mechanical engineering graduate student Marcos devised a clear plastic device about the size and shape of a microscope slide. Depending on the organism being studied, nutrients or prey are injected with a syringe-based pump into the device's microfluidic channel, which is 45 mm long, 3 mm wide and 50 micrometers deep. "While relying on different swimming strategies, all three organisms exhibited behaviors which permitted efficient and rapid exploitation of resource patches," Stocker said. It took bacteria less than 30 seconds, for example, to congregate within a patch of organic nutrients. This new laboratory tool creates a microhabitat where tiny sea creatures live, swim, assimilate chemicals and eat each other. It provides the first methodological, sub-millimeter scale examination of a food web that includes single-celled phytoplankton, bacteria and protozoan predators in action. "Rather than simply floating in the ocean and passively taking up the chemicals required for growth, many microbes exhibit sophisticated behaviors as they forage in an environment where patches of nutrients and resources are few and far between," Seymour said. Oceanographic ecological research has typically taken place at much larger scales because of the difficulty of measuring the behavioral responses of small populations of microorganisms in very small volumes of seawater. "To understand how environmental fluctuations affect the ecology of populations, it is imperative to understand the foraging abilities and behavior of marine microbes at environmentally relevant scales," the authors wrote. Source: Massachusetts institute of technology

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Chemical engineers use carbon nanotubes to monitor chemotherapy, detect toxins at the single-molecule level

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Researchers have created a new family of fluorescent probes called hydrocyanines that can be used to detect and measure the presence of reactive oxygen species. Reactive oxygen species are highly reactive metabolites of oxygen that have been implicated in a variety of inflammatory diseases, including cancer and atherosclerosis. http://www.eurekalert.org/multimedia/pub/rel/11297_rel.jpg "We've shown that the hydrocyanines we developed are able to detect the reactive oxygen species, superoxide and the hydroxide radical, in living cells, tissue samples, and for the first time, in vivo," said Niren Murthy, assistant professor in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University. Details of the hydrocyanine synthesis process and experimental results showing the ability of the dyes to detect reactive oxygen species in cells, tissues and mouse models were reported on December 8 in the online version of the journal Angewandte Chemie International Edition. This research is supported by the National Institutes of Health and the National Science Foundation. The researchers have created six hydrocyanine dyes to date – hydro-Cy3, hydro-Cy5, hydro-Cy7, hydro-IR-676, hydro-IR-783 and hydro-ICG – but say that there are potentially 40 probes that could be created. The dyes vary in their ability to detect intracellular or extracellular reactive oxygen species and by their emission wavelength – from 560 to 830 nanometers. Fluorescing at higher wavelengths allows the hydrocyanine dyes to be used for deep tissue imaging in vivo, a capability that dihydroethidium (DHE), the current "gold standard" for imaging reactive oxygen species, does not have. The dyes also have other advantages over DHE. "When DHE comes into contact with reactive oxygen species, it oxidizes into ethidium bromide, a common mutagen, which means it's toxic and can't be injected inside the body," explained Murthy. "DHE also auto-oxidizes in the presence of aqueous solutions, which creates high levels of background fluorescence and interferes with reactive oxygen species measurements." Hydrocyanines are also simple and quick to synthesize, according to Coulter Department postdoctoral fellow Kousik Kundu. Sodium borohydride is added to commercially available cyanine dyes and the solvent is removed – the one-step process takes less than five minutes. W. Robert Taylor, a professor in the Coulter Department and Emory's Division of Cardiology, and Emory postdoctoral fellow Sarah Knight, tested the ability of the dyes to detect reactive oxygen species inside of cells and animals. For their first experiment, they tested the ability of hydro-Cy3, which has an emission wavelength of 560 nanometers, to detect reactive oxygen species production in the aortic smooth muscle cells of rats. They incubated the cells with hydro-Cy3 and angiotensin II, which is a stimulator of reactive oxygen species that is implicated in the development of atherosclerosis and hypertension. Results showed that cells incubated with angiotensin II and hydro-Cy3 displayed intense intracellular fluorescence, whereas control cells incubated with hydro-Cy3 and phosphate buffer saline displayed significantly lower fluorescence. When they introduced TEMPOL, a molecule that intercepts the reactive oxygen species so that they cannot interact, the cells treated with angiotensin II and hydro-Cy3 displayed a dramatic decrease in fluorescence. "This test demonstrated that the cellular fluorescence was due to intracellular reactive oxygen species production," said Murthy. "What was even more exciting was that we saw that once the hydrocyanine dye was oxidized, it stayed in the cell and the fluorescence was not extinguished by cellular metabolism, which is what happens with DHE." http://www.eurekalert.org/images/clear.gif http://www.eurekalert.org/images/clear.gif http://www.eurekalert.org/images/corner_tl.jpg http://www.eurekalert.org/images/clear.gif http://www.eurekalert.org/images/corner_tr.jpg http://www.eurekalert.org/images/clear.gif http://www.eurekalert.org/images/clear.gif http://www.eurekalert.org/images/clear.gif http://www.eurekalert.org/multimedia/pub/rel/11299_rel.jpg A new family of reactive oxygen species (ROS) probes http://www.eurekalert.org/images/clear.gif http://www.eurekalert.org/images/clear.gif http://www.eurekalert.org/images/clear.gif http://www.eurekalert.org/images/corner_bl.jpg http://www.eurekalert.org/images/clear.gif http://www.eurekalert.org/images/corner_br.jpg http://www.eurekalert.org/images/clear.gif http://www.eurekalert.org/images/clear.gif The researchers also investigated the ability of hydro-Cy3 to image reactive oxygen species production in live mouse aorta tissue, which exhibit a physiological environment that closely resembles in vivo conditions. Explants were incubated with hydro-Cy3 and either lipopolysaccharide endotoxin (LPS), an inflammatory molecule that binds to aortic cells and causes reactive oxygen species to be produced, or the control saline solution. Samples treated with hydro-Cy3 and LPS showed fluorescence intensity almost four times greater than explants treated with hydro-Cy3 and saline. Once more, adding TEMPOL to the sample with hydro-Cy3 and LPS decreased the fluorescence to a level comparable to the control saline explants. After the successful cell culture and tissue experiments, the researchers progressed to in vivo mouse imaging studies. Hydro-Cy7 was selected for the in vivo tests because of its higher emission wavelength of 760 nanometers. LPS-treated mice showed twofold greater fluorescence intensity in the abdominal area than those treated with saline. "Given their ability to detect reactive oxygen species in living cells, tissue samples and in vivo, we believe these dyes will enhance the ability of researchers to measure reactive oxygen species," noted Murthy. The researchers' ultimate goal, though, is to use the dyes in clinical applications. "We want to use these hydrocyanine dyes to detect overproduction of reactive oxygen species at an early stage inside the body so that we can identify patients who are more likely to suffer from these inflammatory diseases," added Murthy. source: Gregoria institute of technology

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Physicists have taken a significant step toward creation of quantum networks by establishing a new record for the length of time that quantum information can be stored in and retrieved from an ensemble of very cold atoms. Though the information remains usable for just milliseconds, even that short lifetime should be enough to allow transmission of data from one quantum repeater to another on an optical network. The new record – seven milliseconds for rubidium atoms stored in a dipole optical trap – was reported December 7 in the online version of the journal Nature Physics by researchers at the Georgia Institute of Technology. The previous record for storage time was 32 microseconds, a difference of more than two orders of magnitude. “This is a really significant step for us, because conceptually it allows long memory times necessary for long-distance quantum networking,” said Alex, associate professor in the Georgia Tech School of Physics and a co-author of the paper. “For multiple architectures with many memory elements, several milliseconds would allow the movement of light across a thousand kilometers.” The keys to extending the storage time included the use of a one-dimensional optical lattice to help confine the atoms and selection of an atomic phase that is insensitive to magnetic effects. The research was sponsored by the National Science Foundation, the A.P. Sloan Foundation and the U.S. Office of Naval Research. The general purpose of quantum networking or quantum computing is to distribute entangled qubits – two correlated data bits that are either “0” or “1” – over long distances. The qubits would travel as photons across existing optical networks that are part of the global telecommunications system. http://gtresearchnews.gatech.edu/images/quantum-memory-95_md.jpg A Georgia Tech research group poses with optical equipment that was used to establish a new record for the storage of quantum information. l. Because of loss in the optical fiber that makes up networks, repeaters must be installed at regular intervals – about every 100 kilometers – to boost the signal. Those repeaters will need quantum memory to receive the photonic signal, store it briefly and then produce a photonic signal that will carry the information to the next node, and on to its final destination. For their memory, the Georgia Tech researchers used an ensemble of rubidium-87 atoms that is cooled to almost absolute zero to minimize atomic motion. To store information, the entire atomic ensemble is exposed to laser light carrying a signal, which allows each atom to participate in the storage as part of a “collective excitation.” In simple terms, each atom “sees” the incoming signal – which is a rapidly oscillating electromagnetic field – slightly differently. Each atom is therefore imprinted with phase information that can later be “read” from the ensemble with another laser. Even though they are very cold, the atoms of the ensemble are free to move in a random way. Because each atom stores a portion of the quantum information and that data’s usefulness depends on each atom’s location in reference to other atoms, significant movement of the atoms could destroy the information. “The challenge for us in implementing these long-lived quantum memories is to preserve the phase imprinting in the atomic ensemble for as long as possible,” explained Stewart Jenkins, a School of Physics research scientist who participated in the research. “It turns out that is difficult to do experimentally.” To extend the lifetime of their memory, the Georgia Tech researchers took two approaches. The first was to confine the atoms using an optical lattice composed of laser beams. Because of the laser frequencies chosen, the atoms are attracted to specific locations within the lattice, though they are not held tightly in place. Because the ensemble atoms are affected by environmental conditions such as magnetism, the second strategy was to use atoms that had been pumped to the so-called “clock transition state” that is relatively insensitive to magnetic fields. “The most critical aspect to getting these long coherence times was the optical lattice,” Jenkins explained. “Although atoms had been confined in optical lattices before, what we did was to use this tool in the context of implementing quantum memory.” Other research teams have stored quantum information in single atoms or ions. This simpler approach allows longer storage periods, but has limitations, he said. “The advantage of using these ensembles as opposed to single atoms is that if we shine into them a ‘read’ laser field, because these atoms have a particular phase imprinted on them, we know with a high degree of probability that we are going to get a second photon – the idler photon – coming out in a particular direction,” Jenkins explained. “That allows us to put a detector in the right location to read the photon.” Though the work significantly advances quantum memories, practical quantum networks probably are at least a decade away, Kuzmich believes. “In practice, you will need to make robust repeater nodes with hundreds of memory elements that can be quickly manipulated and coupled to the fiber,” he said. “There is likely to be slow progress in this area with researchers gaining better and better control of quantum systems. Eventually, they will get good enough so we can make a jump to having systems that can work outside the laboratory environment.” In addition to Kuzmich and Jenkins, the research team included Ran Zhao, Yaroslav Dudin, Corey Campbell, Dzmitry Matsukevich, and Brian Kennedy, a professor in the School of Physics.

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The oldest surviving human brain in Britain, dating back at least 2000 years to the Iron Age, has been unearthed during excavations on the site of the University of York’s campus expansion at Heslington East. Archaeologists from York Archaeological Trust, commissioned by the University to carry out the exploratory dig, made the discovery in an area of extensive prehistoric farming landscape of fields, trackways and buildings dating back to at least 300 BC. And they believe the skull, which was found on its own in a muddy pit, may have been a ritual offering. As Finds Officer Rachel Cubitt cleaned the soil-covered skull’s outer surface, she felt something move inside the cranium. Peering through the base of the skull, she spotted an unusual yellow substance. "It jogged my memory of a university lecture on the rare survival of ancient brain tissue. We gave the skull special conservation treatment as a result, and sought expert medical opinion," she said. York Hospital’s sophisticated CT scanner was used to produce startlingly clear images of the skull’s contents. Philip Duffey, Consultant Neurologist at the Hospital said: "I’m amazed and excited that scanning has shown structures which appear to be unequivocally of brain origin. I think that it will be very important to establish how these structures have survived, whether there are traces of biological material within them and, if not, what is their composition." Dr Sonia O’Connor, Research Fellow in Archaeological Sciences at the University of Bradford added: "The survival of brain remains where no other soft tissues are preserved is extremely rare. This brain is particularly exciting because it is very well preserved, even though it is the oldest recorded find of this type in the UK, and one of the earliest worldwide." The find is the second major discovery during archaeological investigations on the site of the University’s £500 million campus expansion. Earlier this year, a team from the University’s Department of Archaeology unearthed the skeleton of a man believed to be one of Britain’s earliest victims of tuberculosis in a shallow grave. Radiocarbon dating suggests that the man died in the fourth century late-Roman period. The Vice-Chancellor of the University of York, Professor Brian Cantor, said: "The skull is another stunning discovery and its further study will provide us with incomparable insights into life in the Iron Age." There are now plans for a team of specialists to carry out further tests on the skull. They hope to solve the mystery of why such brains survive death and burial, what this might tell us about burial practices, the nature of the burial environment and, perhaps, about the individual whose brain it was. Source: University of York

Is obesity all in your head?

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New research suggests that genes that predispose people to obesity act in the brain and that perhaps some people are simply hardwired to overeat.

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It's a tie! The new record-holder for dimmest known star-like object in the universe goes to twin "failed" stars, or brown dwarfs, each of which shines feebly with only one millionth the light of our sun. Previously, astronomers thought the pair of dim bulbs was just one typical, faint brown dwarf with no record-smashing titles. But when NASA's Spitzer Space Telescope observed the brown dwarf with its heat-seeking infrared vision, it was able to accurately measure the object's extreme faintness and low temperature for the first time. What's more, the Spitzer data revealed the brown dwarf is, in fact, twins. "Both of these objects are the first to break the barrier of one millionth the total light-emitting power of the sun," said Adam Burgasser of the Massachusetts Institute of Technology, Cambridge. Burgasser is lead author of a new paper about the discovery appearing in the Astrophysical Journal Letters. Brown dwarfs are the misfits of the cosmos. They are compact balls of gas floating freely in space, but they are too cool and lightweight to be stars, and too warm and massive to be planets. The name "brown dwarf" comes from the fact that these small, star-like bodies change color over time as they cool, and thus have no definitive color. In reality, most brown dwarfs would appear reddish if they could be seen with the naked eye. Their feeble light output also means they are hard to find. The first brown dwarf wasn't discovered until 1995. While hundreds are known today, astronomers say there are many more in space still waiting to be discovered. The newfound dim duo of brown dwarfs, while notable for their exceptional faintness, will probably not be remembered for their name. They are called 2MASS J09393548-2448279 after the Two Micron All-Sky Survey, or "2MASS," the mission partially funded by NASA that first detected the object in 1999. Astronomers recently used Spitzer's ultrasensitive infrared vision to learn more about the object, which was still thought to be a solo brown dwarf. These data revealed a warm atmospheric temperature of 565 to 635 Kelvin (560 to 680 degrees Fahrenheit). While this is hundreds of degrees hotter than Jupiter, it's still downright cold as far as stars go. In fact, 2MASS J09393548-2448279, or 2M 0939 for short, is one of the coldest star-like bodies measured so far. To calculate the object's brightness, the researchers had to first determine its distance from Earth. After three years of precise measurements with the Anglo-Australian Observatory in Australia, they concluded that 2M 0939 is the fifth-closest known brown dwarf to us, 17 light-years away toward the constellation Antlia. This distance, together with Spitzer's measurements, told the astronomers the object was both cool and extremely dim. But something was puzzling. The brightness of the object was twice what would be expected for a brown dwarf with its particular temperature. The solution? The object must have twice the surface area. In other words, it's twins, with each body shining only half as bright, and each with a mass of 30 to 40 times that of Jupiter. Both bodies are one million times fainter than the sun in total light, and at least one billion times fainter in visible light alone. "These brown dwarfs are the lowest power stellar light bulbs in the sky that we know of," said Burgasser. "And like low-energy fluorescent light bulbs, they emit most of their light in a narrow range of wavelengths, in this case in the infrared." According to the authors, there are even dimmer brown dwarfs scattered throughout the universe, most too faint to see with current sky surveys. NASA's upcoming Wide-Field Infrared Survey Explorer mission will scan the entire sky at infrared wavelengths, and is expected to uncover hundreds of these inconspicuous characters. "The holy grail in the study of brown dwarfs is to find out how low you can go in terms of temperature, mass and brightness," said Davy Kirkpatrick, a co-author of the paper at NASA's Infrared Processing and Analysis Center at the California Institute of Technology, Pasadena. "This will tell us more about how brown dwarfs form and evolve." Other authors of this paper are Chris Tinney of the University of New South Wales, Australia; Michael C. Cushing of the University of Hawaii, Manoa; Didier Saumon of the Los Alamos National Laboratory, NM; Mark S. Marley, NASA Ames Research Center, Moffett Field, Calif.; and Clara S. Bennett of the Massachusetts Institute of Technology. NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology, also in Pasadena. Caltech manages JPL for NASA. More information about Spitzer is at: Spitzer Space Telescope and NASA - SPITZER . Source: JPL