Sensing gravity with acid: Scientists discover role for protons in neurotransmission

While probing how organisms sense gravity and acceleration, scientists at the Marine Biological Laboratory (MBL) and the University of Utah uncovered evidence that acid (proton concentration) plays a key role in communication between neurons. The surprising discovery is reported this week in the Proceedings of the National Academy of Sciences.The team, led by the late MBL senior scientist Stephen M. Highstein, discovered that sensory cells in the inner ear continuously transmit information on orientation of the head relative to gravity and low-frequency motion to the brain using protons as the key means of synaptic signal transmission. (The synapse is the structure that allows one neuron to communicate with another by passing a chemical or electrical signal between them.)”This addresses how we sense gravity and other low-frequency inertial stimuli, like acceleration of an automobile or roll of an airplane,” says co-author Richard Rabbitt, a professor at University of Utah and adjunct faculty member in the MBL’s Program in Sensory Physiology and Behavior. “These are very long-lasting signals requiring a a synapse that does not fatigue or lose sensitivity over time. Use of protons to acidify the space between cells and transmit information from one cell to another could explain how the inner ear is able to sense tonic signals, such as gravity, in a robust and energy efficient way.”The team found that this novel mode of neurotransmission between the sensory cells (type 1 vestibular hair cells) and their target afferent neurons (calyx nerve terminals), which send signals to the brain, is continuous or nonquantal. This nonquantal transmission is unusual and, for low-frequency stimuli like gravity, is more energy efficient than traditional synapses in which chemical neurotransmitters are packaged in vesicles and released quantally.The calyx nerve terminal has a ball-in-socket shape that envelopes the sensory hair cell and helps to capture protons exiting the cell. “The inner-ear vestibular system is the only place where this particular type of synapse is present,” Rabbitt says. “But the fact that protons are playing a key role here suggests they are likely to act as important signaling molecules in other synapses as well.”Previously, Erik Jorgensen of University of Utah (who recently received a Lillie Research Innovation Award from the MBL and the University of Chicago) and colleagues discovered that protons act as signaling molecules between muscle cells in the worm C. elegans and play an important role in muscle contraction. …

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Novel battleground for plant-pathogen interactions

Scientists at The Sainsbury Laboratory in Norwich, with collaborators at Michigan State University and the University of Illinois, have unveiled a new way in which plants perceive pathogens to activate immunity. They also show how pathogens inhibit the mechanism to cause disease. It was previously only associated with other processes in mammalian cells.When plants detect microbial molecules, they trigger immune responses to prevent disease. Although several plant immune receptors for these microbial molecules are known, how they are activated once the microbe is recognized is not well understood.In a study published this week in the journal Science, the scientists found that phosphorylation of an amino acid called tyrosine — phosphorylation being a process that can turn molecules on or off — is key for activating plant immune receptors. This mechanism is already known to play an essential role in the activation of mammalian receptors, and its mis-regulation is often linked to important chronic diseases.The current study shows for the first time that the modification occurs in plant immune receptors as well.”This finding opens the door to improving crop disease resistance as we can investigate ways to optimize how plants recognize pathogenic microbes,” says Professor Cyril Zipfel.”It also provides a new link between our understanding of cellular signalling in plant and animal cells.”In the same study, the researchers discovered that pathogenic bacteria use an enzyme secreted within plant cells to derail the plant’s immune response. They use an enzyme to remove tyrosine phosphorylation from immune receptors, quelling the plant’s signalling mechanisms. Inhibiting the immune response allows bacteria to cause disease.”Our research highlights a battle between hosts and pathogens to take control of an important mechanism,” said first author Dr Alberto Macho from The Sainsbury Laboratory.”Control over this mechanism to activate immune receptors determines whether a plant stays healthy or suffers from disease,” he says.Story Source:The above story is based on materials provided by Norwich BioScience Institutes. Note: Materials may be edited for content and length.

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Superbright, fast X-rays image single layer of proteins

In biology, a protein’s shape is key to understanding how it causes disease or toxicity. Researchers who use X-rays to take snapshots of proteins need a billion copies of the same protein stacked and packed into a neat crystal. Now, scientists using exceptionally bright and fast X-rays can take a picture that rivals conventional methods with a sheet of proteins just one protein molecule thick.Using a type of laser known as XFEL, the technique opens the door to learning the structural details of almost 25 percent of known proteins, many of which have been overlooked due to their inability to stack properly. The team of researchers led by the Department of Energy’s Pacific Northwest and Lawrence Livermore National Laboratories report their results with this unique form of X-ray diffraction in the March issue of the International Union of Crystallography Journal.”In this paper, we’re proving it’s possible to use an XFEL to study individual monolayers of protein,” said PNNL microscopist James Evans. “Just being able to see any diffraction is brand new.”Evans co-led the team of two dozen scientists with LLNL physicist Matthias Frank. The bright, fast X-rays were produced at the Linac Coherent Light Source at SLAC National Accelerator Laboratory in Menlo Park, Calif., the newest of DOE’s major X-ray light source facilities at the national laboratories. LCLS, currently the world’s most powerful X-ray laser, is an X-ray free-electron laser. It produces beams millions of times brighter than earlier X-ray light sources.Coming in at around 8 angstrom resolution (which can make out items a thousand times smaller than the width of a hair), the proteins appear slightly blurry but match the expected view based on previous research. Evans said this level of clarity would allow researchers, in some cases, to see how proteins change their shape as they interact with other proteins or molecules in their environment.To get a clearer view of protein monolayers using XFEL, the team will need to improve the resolution to 1 to 3 angstroms, as well as take images of the proteins at different angles, efforts that are currently underway.Not Your Family’s CrystalResearchers have been using X-ray crystallography for more than 60 years to determine the shape and form of proteins that form the widgets and gears of a living organism’s cells. The conventional method requires, however, that proteins stack into a large crystal, similar to how oranges stack in a crate. …

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First global geologic map of Jupiter’s largest moon Ganymede details an icy world

More than 400 years after its discovery by Galileo, the largest moon in the solar system has finally claimed a spot on the map.A team of scientists led by Wes Patterson of the Johns Hopkins Applied Physics Laboratory (APL), Laurel, Md., and Geoffrey Collins of Wheaton College, Norton, Mass., has produced the first global geologic map of Ganymede, a Galilean moon of Jupiter. Published by the U.S. Geological Survey, the map technically illustrates the varied geologic character of Ganymede’s surface, and is the first complete global geologic map of an icy, outer-planet moon.Patterson, Collins and colleagues used images from NASA’s Voyager and Galileo missions to create the map. It’s only the fourth of its kind covering a planetary satellite; similar maps exist for Earth’s moon as well as Jupiter’s moons Io and Callisto.”By mapping all of Ganymede’s surface, we can more accurately address scientific questions regarding the formation and evolution of this truly unique moon,” says Patterson, a planetary scientist.Since its discovery in January 1610, Ganymede has been the focus of repeated observation, first by Earth-based telescopes, and later by flyby missions and spacecraft orbiting Jupiter. These studies depict a complex icy world whose surface is characterized by the striking contrast between its two major terrain types: the dark, very old, highly cratered regions; and the lighter, somewhat younger (but still ancient) regions marked with an extensive array of grooves and ridges.  With a diameter of 3,280 miles (5,262 kilometers), Ganymede is larger than both planet Mercury and dwarf planet Pluto. It’s also the only satellite in the solar system known to have its own magnetosphere. The map details geologic features of the moon that formed and evolved over much of our solar system’s history. These features record evidence of Ganymede’s internal evolution, its dynamical interactions with the other Galilean satellites, and the evolution of the small bodies that have impacted Ganymede’s surface.The new chart will be a valuable tool for researchers to compare the geologic characters of other icy moons, since almost any type of feature that is found on other icy satellites has a similar feature somewhere on Ganymede. And with a surface over half as large as all the land area on Earth, Ganymede offers a wide variety of locations to observe. …

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New pathway for fear discovered deep within brain

Fear is primal. In the wild, it serves as a protective mechanism, allowing animals to avoid predators or other perceived threats. For humans, fear is much more complex. A normal amount keeps us safe from danger. But in extreme cases, like post-traumatic stress disorder (PTSD), too much fear can prevent people from living healthy, productive lives. Researchers are actively working to understand how the brain translates fear into action. Today, scientists at Cold Spring Harbor Laboratory (CSHL) announce the discovery of a new neural circuit in the brain that directly links the site of fear memory with an area of the brainstem that controls behavior.How does the brain convert an emotion into a behavioral response? For years, researchers have known that fear memories are learned and stored in a small structure in the brain known as the amygdala. Any disturbing event activates neurons in the lateral and then central portions of the amygdala. The signals are then communicated internally, passing from one group of neurons to the next. …

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How our brain networks: White matter ‘scaffold’ of human brain revealed

For the first time, neuroscientists have systematically identified the white matter “scaffold” of the human brain, the critical communications network that supports brain function.Their work, published Feb. 11 in the open-source journal Frontiers in Human Neuroscience, has major implications for understanding brain injury and disease. By detailing the connections that have the greatest influence over all other connections, the researchers offer not only a landmark first map of core white matter pathways, but also show which connections may be most vulnerable to damage.”We coined the term white matter ‘scaffold’ because this network defines the information architecture which supports brain function,” said senior author John Darrell Van Horn of the USC Institute for Neuroimaging and Informatics and the Laboratory of Neuro Imaging at USC.”While all connections in the brain have their importance, there are particular links which are the major players,” Van Horn said.Using MRI data from a large sample of 110 individuals, lead author Andrei Irimia, also of the USC Institute for Neuroimaging and Informatics, and Van Horn systematically simulated the effects of damaging each white matter pathway.They found that the most important areas of white and gray matter don’t always overlap. Gray matter is the outermost portion of the brain containing the neurons where information is processed and stored. Past research has identified the areas of gray matter that are disproportionately affected by injury.But the current study shows that the most vulnerable white matter pathways — the core “scaffolding” — are not necessarily just the connections among the most vulnerable areas of gray matter, helping explain why seemingly small brain injuries may have such devastating effects.”Sometimes people experience a head injury which seems severe but from which they are able to recover. On the other hand, some people have a seemingly small injury which has very serious clinical effects,” says Van Horn, associate professor of neurology at the Keck School of Medicine of USC. “This research helps us to better address clinical challenges such as traumatic brain injury and to determine what makes certain white matter pathways particularly vulnerable and important.”The researchers compare their brain imaging analysis to models used for understanding social networks. To get a sense of how the brain works, Irimia and Van Horn did not focus only on the most prominent gray matter nodes — which are akin to the individuals within a social network. Nor did they merely look at how connected those nodes are.Rather, they also examined the strength of these white matter connections, i.e. which connections seemed to be particularly sensitive or to cause the greatest repercussions across the network when removed. …

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Kepler finds a very wobbly planet: Rapid and erratic changes in seasons

Imagine living on a planet with seasons so erratic you would hardly know whether to wear Bermuda shorts or a heavy overcoat. That is the situation on a weird, wobbly world found by NASA’s planet-hunting Kepler space telescope.The planet, designated Kepler-413b, precesses, or wobbles, wildly on its spin axis, much like a child’s top. The tilt of the planet’s spin axis can vary by as much as 30 degrees over 11 years, leading to rapid and erratic changes in seasons. In contrast, Earth’s rotational precession is 23.5 degrees over 26,000 years. Researchers are amazed that this far-off planet is precessing on a human timescale.Kepler 413-b is located 2,300 light-years away in the constellation Cygnus. It circles a close pair of orange and red dwarf stars every 66 days. The planet’s orbit around the binary stars appears to wobble, too, because the plane of its orbit is tilted 2.5 degrees with respect to the plane of the star pair’s orbit. As seen from Earth, the wobbling orbit moves up and down continuously.Kepler finds planets by noticing the dimming of a star or stars when a planet transits, or travels in front of them. Normally, planets transit like clockwork. Astronomers using Kepler discovered the wobbling when they found an unusual pattern of transiting for Kepler-413b.”Looking at the Kepler data over the course of 1,500 days, we saw three transits in the first 180 days — one transit every 66 days — then we had 800 days with no transits at all. …

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Obesity combined with exposure to cigarette smoke may pose new health concerns

Sep. 11, 2013 — Millions of people who are obese and smoke tobacco may face additional health problems — including their responses to common prescription medicines — that extend beyond the well-known links with cancer, heart attacks and stroke, according to a new report.”Our research shows that smoking and obesity together may pose a triple health threat in addition to the increased risks for heart disease, cancer and diabetes,” said Aaron Wright, Ph.D., who reported on the study. “That dangerous combination impacts key mechanisms by which both the lung and liver perform metabolism. For example, the body’s ability to metabolize prescription drugs may be altered in ways that could make standard dosages too high or too low to be effective in obese people who are exposed to tobacco smoke.”Tobacco smoke and obesity also intensifies the cancer-causing potential of cigarette smoke. We were surprised to find that in some instances, the substances in second-hand smoke seem to have a more dramatic effect than just smoking,” he said.Wright described experiments analyzing the activity of a key family of enzymes in liver and lung tissues obtained from lean and obese mice exposed directly to cigarette smoke and second-hand smoke. These cytochrome P450 enzymes (also known as “P450s”) metabolize, or break down, about 75 percent of all prescription and non-prescription drugs, and other ingested substances. The P450 enzyme system ensures that insulin, beta-blockers, oral contraceptives, pain-relievers, tranquilizers and other medications do their work and then disappear from the body. P450s also metabolize fats.Scientists have known for years that cigarette smoke can make some P450 enzymes more active. As a result, smokers may wind up with levels of medication in their blood that are too low to treat a disease. Though they haven’t studied many obese individuals, researchers know that some alterations to the activity of P450 enzymes occur with excess body weight.Wright and colleagues, who are with the Pacific Northwest National Laboratory in Richland, Wash., decided to take a first step toward determining the combined effects of both cigarette smoke and obesity. …

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A swarm on every desktop: Robotics experts learn from public

Sep. 9, 2013 — The next experiment from Rice University’s Multi-Robot Systems Laboratory (MRSL) could happen on your desktop. The lab’s researchers are refining their control algorithms for robotic swarms based upon data from five free online games that anyone can play.”What we learn from the game and our lab experiments applies directly to real-world challenges,” said Aaron Becker, a postdoctoral researcher at MRSL. “For example, if a doctor had a swarm of several thousand microscopic robots, each carrying a tiny payload of anti-cancer drugs, might it be possible to have them all converge on a tumor using magnetic signals from an MRI machine?”In the games, which are available at http://www.swarmcontrol.net, players use simple commands to move groups of robots through mazes and around obstacles. Sometimes the goal is to push a larger object to a particular spot. Other times the goal is to move the collective to a target or to have it assume a specific shape. Each time a game is played, the website collects information about how the task was completed. Becker said the data will be used to develop new control algorithms for robot swarms.”The data from these games will help us better understand how to use multi-robot systems with massive populations to perform coordinated, complex tasks,” said lab director James McLurkin, assistant professor of computer science at Rice.To demonstrate the kind of complex behaviors that can be achieved with simple commands, Becker videotaped an experiment over the Labor Day weekend in which a swarm of a dozen randomly scattered r-one robots were directed to form a complex shape — a capital R. To direct the robots, Becker used a basic controller — a simple one-button, ’80s-era videogame joystick that was capable of giving only two commands: rotate and roll forward.”The robots are all connected to the same joystick, so each robot received exactly the same commands,” Becker said.The experiments were the latest to use the r-one, an inexpensive yet sophisticated multi-robot system that McLurkin began designing in 2009. Each bagel-sized r-one has a radio, a motor, two wheels, dozens of sensors and onboard electronics. …

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Human foot not as unique as originally thought

Aug. 21, 2013 — Research at the University of Liverpool has shown that the mechanisms of the human foot are not as unique as originally thought and have much more in common with the flexible feet of other great apes.Current understanding of the evolution of human walking is based on research from the 1930s, which proposes that human feet function very differently to those of other apes, due to the development of arches in the mid-foot region and the supposed rigidity of that on the outside edge of the foot.In a study of more than 25,000 human steps made on a pressure-sensitive treadmill at the University’s Gait Laboratory, scientists at Liverpool have shown that despite having abandoned life in the trees long ago, our feet have retained a surprising amount of flexibility, the type seen in the feet of other great apes, such as orangutans and chimpanzees, that have remained largely tree-dwelling.Professor Robin Crompton, from the University’s Institute of Ageing and Chronic Disease, explains: “It has long been assumed that because we possess lateral and medial arches in our feet — the lateral one supposedly being rigid and supported in bone -, that our feet differ markedly to those of our nearest relatives, whose mid-foot is fully flexible and makes regular ground contact.”This supposed ‘uniqueness’, however, has never been quantitatively tested. We found that the range of pressures exerted under the human mid-foot, and thus the internal mechanisms that drive them, were highly variable, so much so that they actually overlapped with those made by the great apes.”It has previously been thought that humans who make contact with the ground with the mid-foot region are primarily those that suffer from diabetes or arthritis, both of which can impact on the structure of the feet. Research showed, however, that two thirds of normal healthy subjects produced some footfalls where the mid-foot touches the ground, with no indication that this is other than an aspect of normal healthy walking.Dr Karl Bates, from the University’s Institute of Ageing and Chronic Disease, said: “Our ancestors probably first developed flexibility in their feet when they were primarily tree-dwelling, and moving on bendy branches, but as time passed and we became more and more ground-dwelling animals, some new features evolved to enable us to move quickly on the ground.”Our limbs, however, did not adapt to life on the ground anywhere near as much as those of other ground-dwelling animals such as horses, hares and dogs. Our tests showed that our feet are not as stiff as originally thought and actually form part of a continuum of variation with those of other great apes.”We hypothesise that despite becoming nearly exclusively ground dwelling we have retained flexibility in the feet to allow us to cope effectively with the differences in hard and soft ground surfaces which we encounter in long distance walking and running. The next part of our study will be testing this theory, which could offer a reason why humans can outrun a horse, for example, over long distances on irregular terrain.”

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Cosmology in the lab using laser-cooled ions

Aug. 12, 2013 — Scientists would love to know which forces created our universe some 14 billion years ago. How could — due to a breaking of symmetry — matter, and thus stars and galaxies, be created from an originally symmetrical universe in which the same conditions prevailed everywhere shortly after the Big Bang. Now, the Big Bang is an experiment that cannot be repeated. But the principle of symmetry and its disturbance can definitely be investigated under controlled laboratory conditions.For this purpose, scientists from the Excellence Cluster QUEST at the Physikalisch-Technische Bundesanstalt (PTB) used laser-cooled ions in so-called “ion Coulomb crystals.” They were able to show for the first time how symmetry breaking can be generated in a controlled manner and how the occurrence of defects can then be observed. Realizing these so-called “topographical defects” within a well-controlled system opens up new possibilities when it comes to investigating quantum phase transitions and looking in detail into the non-equilibrium dynamics of complex systems. The results have been published in the current issue of the scientific journal Nature Communications.Within the scope of an international cooperation with colleagues from the Los Alamos National Lab (USA), from the University of Ulm (Germany) and from the Hebrew University (Israel), PTB researchers have now, for the first time, succeeded in demonstrating topological defects in an atomic-optical experiment in the laboratory. Topological defects are errors in the spatial structure which are caused by the breaking of the symmetry when particles of a system cannot communicate with each other. They form during a phase transition and present themselves as non-matching areas. For their activities, the scientists used the symmetry properties of ion Coulomb crystals which are comparable to those of the early universe.The experimental challenge for the researchers working with Tanja Mehlstäubler consisted in being able to control a complex multi-particle system and to induce an intentional change in the external conditions to obtain the symmetry breaking. …

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Neuroscientists identify protein linked to Alzheimer’s-like afflictions

Aug. 11, 2013 — A team of neuroscientists has identified a modification to a protein in laboratory mice linked to conditions associated with Alzheimer’s Disease. Their findings, which appear in the journal Nature Neuroscience, also point to a potential therapeutic intervention for alleviating memory-related disorders.The research centered on eukaryotic initiation factor 2 alpha (eIF2alpha) and two enzymes that modify it with a phosphate group; this type of modification is termed phosphorylation. The phosphorylation of eIF2alpha, which decreases protein synthesis, was previously found at elevated levels in both humans diagnosed with Alzheimer’s and in Alzheimer’s Disease (AD) model mice.”These results implicate the improper regulation of this protein in Alzheimer’s-like afflictions and offer new guidance in developing remedies to address the disease,” said Eric Klann, a professor in New York University’s Center for Neural Science and the study’s senior author.The study’s co-authors also included: Douglas Cavener, a professor of biology at Pennsylvania State University; Clarisse Bourbon, Evelina Gatti, and Philippe Pierre of Université de la Méditerranée in Marseille, France; and NYU researchers Tao Ma, Mimi A. Trinh, and Alyse J. Wexler.It has been known for decades that triggering new protein synthesis is vital to the formation of long-term memories as well as for long-lasting synaptic plasticity — the ability of the neurons to change the collective strength of their connections with other neurons. Learning and memory are widely believed to result from changes in synaptic strength.In recent years, researchers have found that both humans with Alzheimer’s Disease and AD model mice have relatively high levels of eIF2alpha phosphorylation. But the relationship between this characteristic and AD-related afflictions was unknown.Klann and his colleagues hypothesized that abnormally high levels of eIF2alpha phosphorylation could become detrimental because, ultimately, protein synthesis would diminish, thereby undermining the ability to form long-term memories.To explore this question, the researchers examined the neurological impact of two enzymes that phosphorylate eIF2alpha, kinases termed PERK and GCN2, in different populations of AD model mice — all of which expressed genetic mutations akin to those carried by humans with AD. These were: AD model mice; AD model mice that lacked PERK; and AD model mice that lacked GCN2.Specifically, they looked at eIF2alpha phosphorylation and the regulation of protein synthesis in the mice’s hippocampus region — the part of the brain responsible for the retrieval of old memories and the encoding of new ones. They then compared these levels with those of postmortem human AD patients.Here, they found both increased levels of phosphorylated eIF2alpha in the hippocampus of both AD patients and the AD model mice. …

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Printing silver onto fibers could pave the way for flexible, wearable electronics

July 30, 2013 — A new technique for depositing silver onto clothing fibres could open up huge opportunities in wearable electronics.Scientists at the National Physical Laboratory (NPL), the UK’s National Measurement Institute, have developed a way to print silver directly onto fibres. This new technique could make integrating electronics into all types of clothing simple and practical. This has many potential applications in sports, health, medicine, consumer electronics and fashion.Most current plans for wearable electronics require weaving conductive materials into fabrics, which offer limited flexibility and can only be achieved when integrated into the design of the clothing from the start. NPL’s technique could allow lightweight circuits to be printed directly onto complete garments.Silver coated fibres created using this technique are flexible and stretchable, meaning circuits can be easily printed onto many different types of fabric, including wool which is knitted in tight loops.The technique involves chemically bonding a nano‐silver layer onto individual fibres to a thickness of 20 nm. The conductive silver layer fully encapsulates fibres and has good adhesion and excellent conductivity.Chris Hunt, Project Lead, says: “The technique has many potential applications. One particularly exciting area is wearable sensors and antennas which could be used for monitoring, for example checking on patients and vulnerable people; data capture and feedback for soldiers in the field; and performance monitoring in sports. It offers particular benefits over the ‘weaving in’ approach, as the conductive pattern and flexibility ensures that sensors are always positioned in the same location on the body.”The technique could also create opportunities in fashion and consumer technology, such as incorporating LED lighting into clothing or having touch-screens on shirt sleeves.In addition, silver has antibacterial properties, opening up opportunities for medical applications such as wound dressings, face masks, long lasting anti-bacterial wipes, and military clothing.Having successfully shown that the additive technique is viable in the lab, NPL is now looking for funding or collaborators to develop a full printed circuit on a textile, which can be tested for flexibility and robustness, for example by putting it through the wash. Once this has been successfully achieved, the scientists will then look to develop prototypes of practical applications.

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Santa’s workshop not flooded — but lots of melting in the Arctic

July 30, 2013 — Santa’s workshop at the North Pole is not under water, despite recent reports. A dramatic image captured by a University of Washington monitoring buoy reportedly shows a lake at the North Pole. But Santa doesn’t yet need to buy a snorkel.”Every summer when the sun melts the surface the water has to go someplace, so it accumulates in these ponds,” said Jamie Morison, a polar scientist at the UW Applied Physics Laboratory and principal investigator since 2000 of the North Pole Environmental Observatory. “This doesn’t look particularly extreme.”After media coverage in CBS News, The Atlantic and the U.K.’s Daily Mail, Morison returned from overseas travel late last week to a pile of media inquiries. Over the weekend the team posted an explanatory page on the project website.One of the issues in interpreting the image, researchers said, is that the camera uses a fisheye lens.”The picture is slightly distorted,” said Axel Schweiger, who heads the Applied Physics Laboratory’s Polar Science Center. “In the background you see what looks like mountains, and that’s where the scale problem comes in — those are actually ridges where the ice was pushed together.”Researchers estimate the melt pond in the picture was just over 2 feet deep and a few hundred feet wide, which is not unusual to find on an Arctic ice floe in late July.In the midst of all the concern, the pool drained late July 27. This is the normal cycle for a meltwater pond that forms from snow and ice — it eventually drains through cracks or holes in the ice it has pooled on.The now-infamous buoy was first plunked into floating ice in April, at the beginning of the melt season, about 25 miles from the North Pole. Morison drilled a hole about three football fields away for a second camera, which is pointing in a different direction and shows a more typical scene. Since then the ice floe holding both cameras has drifted about 375 miles south.North Pole Environmental Observatory Watch an April interview with Jamie Morison when he was deploying the buoy The U.S. National Science Foundation has funded an observatory since 2000 that makes yearly observations at fixed locations and installs 10 to 15 drifting buoys.The buoys record weather, ice, and ocean data, and the webcams transmit images via satellite every 6 hours. …

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Planetary ‘runaway greenhouse’ more easily triggered, research shows

July 30, 2013 — It might be easier than previously thought for a planet to overheat into the scorchingly uninhabitable “runaway greenhouse” stage, according to new research by astronomers at the University of Washington and the University of Victoria published July 28 in the journal Nature Geoscience.In the runaway greenhouse stage, a planet absorbs more solar energy than it can give off to retain equilibrium. As a result, the world overheats, boiling its oceans and filling its atmosphere with steam, which leaves the planet glowing-hot and forever uninhabitable, as Venus is now.One estimate of the inner edge of a star’s “habitable zone” is where the runaway greenhouse process begins. The habitable zone is that ring of space around a star that’s just right for water to remain in liquid form on an orbiting rocky planet’s surface, thus giving life a chance.Revisiting this classic planetary science scenario with new computer modeling, the astronomers found a lower thermal radiation threshold for the runaway greenhouse process, meaning that stage may be easier to initiate than had been previously thought.”The habitable zone becomes much narrower, in the sense that you can no longer get as close to the star as we thought before going into a runaway greenhouse,” said Tyler Robinson, a UW astronomy postdoctoral researcher and second author on the paper. The lead author is Colin Goldblatt of the University of Victoria.Though further research is called for, the findings could lead to a recalibration of where the habitable zone begins and ends, with some planets having their candidacy as possible habitable worlds revoked.”These worlds on the very edge got ‘pushed in,’ from our perspective — they are now beyond the runaway greenhouse threshold,” Robinson said.Subsequent research, the astronomers say, is needed in part because their computer modeling was done in a “single-column, clear-sky model,” or a one-dimensional measure averaged around a planetary sphere that does not account for the atmospheric effect of clouds.The findings apply to planet Earth as well. As the sun increases in brightness over time, Earth, too, will move into the runaway greenhouse stage — but not for a billion and a half years or so. Still, it inspired the astronomers to write, “As the solar constant increases with time, Earth’s future is analogous to Venus’s past.”Other co-authors are Kevin J. Zahnle of the NASA Ames Research Center in Moffett Field, Calif.; and David Crisp of the Jet Propulsion Laboratory in Pasadena, Calif.

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Silky brain implants may help stop spread of epilepsy

July 25, 2013 — Silk has walked straight off the runway and into the lab. According to a new study published in the Journal of Clinical Investigation, silk implants placed in the brain of laboratory animals and designed to release a specific chemical, adenosine, may help stop the progression of epilepsy.The research was supported by the National Institute of Neurological Disorders and Stroke (NINDS) and the National Institute of Biomedical Imaging and Bioengineering (NIBIB), which are part of the National Institutes of Health.The epilepsies are a group of neurological disorders associated with recurring seizures that tend to become more frequent and severe over time. Adenosine decreases neuronal excitability and helps stop seizures. Earlier studies have suggested abnormally low levels of adenosine may be linked to epilepsy.Rebecca L. Williams-Karnesky, Ph.D. and her colleagues from Legacy Research Institute, Portland, Ore., Oregon Health and Sciences University (OHSU), Portland, and Tufts University, Boston, looked at long-term effects of an adenosine-releasing silk-implant therapy in rats and examined the role of adenosine in causing epigenetic changes that may be associated with the development of epilepsy.The investigators argue that adenosine’s beneficial effects are due to epigenetic modifications (chemical reactions that change the way genes are turned on or off without altering the DNA code, the letters that make up our genetic background). Specifically, these changes happen when a molecule known as a methyl group blocks a portion of DNA, affecting which genes are accessible and can be turned on. If methyl groups have been taken away (demethylated), genes are more likely to turn on.The results reported in the paper provided evidence that changing adenosine levels affects DNA methylation in the brain. Specifically, greater amounts of adenosine were associated with lower levels of DNA methylation. The investigators also demonstrate that rats induced to develop epilepsy have higher levels of methylated DNA. …

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Large study reveals increased cancer risks associated with family history of the disease

July 24, 2013 — A family history of cancer increases the risk of other members of the family developing not only the same cancer (known as a concordant cancer) but also a different (discordant) cancer, according to a large study of 23,000 people in Italy and Switzerland.The research, published in the leading cancer journal Annals of Oncology today (Thursday), provides a comprehensive picture of the risk of developing various different types of cancer in families where there is a history of the disease, and is one of the few large studies of this kind that takes into account other important factors, such as individual characteristics and lifestyles, that could affect the degree of risk as well.Results from the study supported known associations, such as the increased risk of developing the same cancer as a close relative, and the 1.5-fold increased risk of breast cancer in women with a history of colorectal cancer in the family. However, the study also found a 3.3-fold increased risk of developing oral and pharyngeal cancer among people who had a first-degree relative with cancer of the larynx, and a four-fold increased risk of cancer of the gullet (esophageal cancer) where a first-degree relative had oral or pharyngeal cancer. If a first-degree relative had breast cancer, female family members had a 2.3-fold increased risk of ovarian cancer. Family members had a 3.4-fold increased risk of prostate cancer if a first-degree relative had bladder cancer.The researchers from Italy, Switzerland and France looked at 12,000 cases of cancer occurring in 13 different cancer sites (mouth and pharynx, nasopharynx, esophagus, stomach, colorectum, liver, pancreas, larynx, breast, womb, ovaries, prostate and kidneys) between 1991 and 2009. They matched them with 11,000 people without cancer, and collected information on any cancer in the family, particularly in a first-degree relative, age at diagnosis, sociodemographic characteristics, body shape, lifestyle habits such as smoking and alcohol intake, diet, personal medical history, including menstrual and reproductive factors, and use of oral contraceptives and hormone replacement therapy.Dr Eva Negri, head of the Laboratory of Epidemiologic Methods at the Mario Negri Institute for Pharmacological Research, Milan, Italy, said: “Besides confirming and quantifying the well-known excess risks of people developing the same cancer as their first-degree relative, we have identified increased risks for developing a number of different cancers. We have also found that if a patient was diagnosed with certain cancers when they were younger than 60, the risks of a discordant cancer developing in family members were greater.”A major strength of our study is that we were able to adjust our analyses for tobacco, alcohol and a number of other lifestyle habits, which most previous studies have not been able to do.”Dr Negri said that some of the associations between discordant cancers were probably due to shared environmental factors such as family habits of smoking and drinking. However, she said: “Our results point to several potential cancer syndromes that appear among close relatives and that indicate the presence of genetic factors influencing multiple cancer sites. These findings may help researchers and clinicians to focus on the identification of additional genetic causes of selected cancers and on optimizing screening and diagnosis, particularly in people with a family history of cancer at a young age.”She said that the large numbers of patients in the study enabled the researchers to identify associations even for some rare cancers.”For some rare cancers, a weak association with a different, common cancer can, on a population level, reveal a higher attributable risk than a strong association with the risk of developing the same cancer. For example, for ovarian cancer we found that a family history of breast cancer had a stronger attributable risk of ovarian cancer than the far rarer, albeit stronger, association with family history of ovarian cancer.”The researchers are still collecting data on the people they are studying, including biological material, which could help them to identify genetic factors that could be playing a role in the increased risk for people with a family history of cancer. They also plan to investigate whether some well-recognised risk factors are involved in increasing the risk to family members of developing concordant or discordant cancers, and if so, to what extent.

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Organ transplantation as source of fatal rabies virus case

July 23, 2013 — An investigation into the source of a fatal case of raccoon rabies virus exposure indicates the individual received the virus via a kidney transplant 18 months earlier, findings suggesting that rabies transmitted by this route may have a long incubation period, and that although solid organ transplant transmission of infectious encephalitis is rare, further education to increase awareness is needed, according to a study in the July 24/31 issue of JAMA.The rabies virus causes a fatal encephalitis (inflammation of the brain) and can be transmitted through tissue or organ transplantation. “Unique rabies virus variants, distinguishable by molecular typing methods, are associated with specific animal reservoirs. Globally, an estimated 55,000 persons die of rabies every year, with most transmission attributable to dog bites. Approximately 2 human rabies deaths are reported in the United States every year and during 2000 through 2010, all but 2 domestically acquired cases were associated with bats. Despite raccoons being the most frequently reported rabid animal in the United States, only l human rabies case associated with the raccoon rabies virus variant has been reported,” according to background information in the article. In February 2013, a kidney recipient with no reported exposures to potentially rabid animals died from rabies 18 months after transplantation.Neil M. Vora, M.D., of the Centers for Disease Control and Prevention, Atlanta, and colleagues conducted a study to determine whether organ transplantation was the source of rabies virus exposure in the kidney recipient, and to evaluate for and prevent rabies in other transplant recipients (n = 3; right kidney, heart, and liver) from the same donor. Organ donor and all transplant recipient medical records were reviewed. Laboratory tests to detect rabies virus-specific binding antibodies, rabies virus neutralizing antibodies, and rabies virus antigens were conducted on available specimens, including serum, cerebrospinal fluid, and tissues from the donor and the recipients.The researchers found that in retrospect, the kidney donor’s symptoms prior to death were consistent with rabies (the presumed diagnosis at the time of death was ciguatera poisoning [a foodborne illness]). Subsequent interviews with family members revealed that the donor had significant wildlife exposure, and had sustained at least 2 raccoon bites, for which he did not seek medical care. …

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Information in brain cells’ electrical activity combines memory, environment, and state of mind

July 17, 2013 — The information carried by the electrical activity of neurons is a mixture of stored memories, environmental circumstances, and current state of mind, scientists have found in a study of laboratory rats. The findings, which appear in the journal PLoS Biology, offer new insights into the neurobiological processes that give rise to knowledge and memory recall.The study was conducted by Eduard Kelemen, a former graduate student and post-doctoral associate at the State University of New York (SUNY) Downstate Medical Center, and André Fenton, a professor at New York University’s Center for Neural Science and Downstate Medical Center. Kelemen is currently a postdoctoral fellow at University of Tuebingen in Germany.The idea that recollection is not merely a replay of our stored experiences dates back to Plato. He believed that memory retrieval was, in fact, a much more intricate process — a view commonly accepted by today’s cognitive psychologists and couched in the theory of constructive recollection. The theory posits that during memory retrieval, information across different experiences may combine during recall to form a single experience. Such a process may explain the prevalence of false memories. For example, studies have shown that people mistakenly recalled seeing a school bus in a movie if the bus was mentioned after they watched the movie.In addition, other scholarship has shown that a subject’s mindset can also influence the retrieved information. For example, looking at a house from the perspective of a homebuyer or a burglar leads to different recollections — potential purchasers may recall the house’s leaky roof while would-be burglars may remember where the jewelry is kept.But while the psychological contours of retrieval are well-documented, very little is known about the neural activity that underlies this process.With this in mind, Fenton and Kelemen centered their study on the neurophysiological processes rats employ as they solve problems that require memory retrieval. To do so, they employed techniques developed during the last two decades. These involve monitoring the electrical activity of neurons in the rats’ hippocampus — the part of the brain used to encode new memories and retrieve old ones. …

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‘Intelligent knife’ tells surgeon which tissue is cancerous

July 17, 2013 — Scientists have developed an “intelligent knife” that can tell surgeons immediately whether the tissue they are cutting is cancerous or not.In the first study to test the invention in the operating theatre, the “iKnife” diagnosed tissue samples from 91 patients with 100 per cent accuracy, instantly providing information that normally takes up to half an hour to reveal using laboratory tests.The findings, by researchers at Imperial College London, are published today in the journal Science Translational Medicine. The study was funded by the National Institute for Health Research (NIHR) Imperial Biomedical Research Centre, the European Research Council and the Hungarian National Office for Research and Technology.In cancers involving solid tumours, removal of the cancer in surgery is generally the best hope for treatment. The surgeon normally takes out the tumour with a margin of healthy tissue. However, it is often impossible to tell by sight which tissue is cancerous. One in five breast cancer patients who have surgery require a second operation to fully remove the cancer. In cases of uncertainty, the removed tissue is sent to a lab for examination while the patient remains under general anaesthetic.The iKnife is based on electrosurgery, a technology invented in the 1920s that is commonly used today. Electrosurgical knives use an electrical current to rapidly heat tissue, cutting through it while minimising blood loss. In doing so, they vaporise the tissue, creating smoke that is normally sucked away by extraction systems.The inventor of the iKnife, Dr Zoltan Takats of Imperial College London, realised that this smoke would be a rich source of biological information. To create the iKnife, he connected an electrosurgical knife to a mass spectrometer, an analytical instrument used to identify what chemicals are present in a sample. Different types of cell produce thousands of metabolites in different concentrations, so the profile of chemicals in a biological sample can reveal information about the state of that tissue.In the new study, the researchers first used the iKnife to analyse tissue samples collected from 302 surgery patients, recording the characteristics of thousands of cancerous and non-cancerous tissues, including brain, lung, breast, stomach, colon and liver tumours to create a reference library. …

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