Shocking behavior of a runaway star: High-speed encounter creates arc

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Roguish runaway stars can have a big impact on their surroundings as they plunge through the Milky Way galaxy. Their high-speed encounters shock the galaxy, creating arcs, as seen in a newly released image from NASA’s Spitzer Space Telescope.In this case, the speedster star is known as Kappa Cassiopeiae, or HD 2905 to astronomers. It is a massive, hot supergiant moving at around 2.5 million mph relative to its neighbors (1,100 kilometers per second). But what really makes the star stand out in this image is the surrounding, streaky red glow of material in its path. Such structures are called bow shocks, and they can often be seen in front of the fastest, most massive stars in the galaxy.Bow shocks form where the magnetic fields and wind of particles flowing off a star collide with the diffuse, and usually invisible, gas and dust that fill the space between stars. How these shocks light up tells astronomers about the conditions around the star and in space. Slow-moving stars like our sun have bow shocks that are nearly invisible at all wavelengths of light, but fast stars like Kappa Cassiopeiae create shocks that can be seen by Spitzer’s infrared detectors.Incredibly, this shock is created about 4 light-years ahead of Kappa Cassiopeiae, showing what a sizable impact this star has on its surroundings. (This is about the same distance that we are from Proxima Centauri, the nearest star beyond the sun.)The Kappa Cassiopeiae bow shock shows up as a vividly red color. The faint green features in this image result from carbon molecules, called polycyclic aromatic hydrocarbons, in dust clouds along the line of sight that are illuminated by starlight.Delicate red filaments run through this infrared nebula, crossing the bow shock. Some astronomers have suggested these filaments may be tracing out features of the magnetic field that runs throughout our galaxy. …


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Solar-induced hybrid fuel cell produces electricity directly from biomass

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Although low temperature fuel cells powered by methanol or hydrogen have been well studied, existing low temperature fuel cell technologies cannot directly use biomass as a fuel because of the lack of an effective catalyst system for polymeric materials.Now, researchers at the Georgia Institute of Technology have developed a new type of low-temperature fuel cell that directly converts biomass to electricity with assistance from a catalyst activated by solar or thermal energy. The hybrid fuel cell can use a wide variety of biomass sources, including starch, cellulose, lignin — and even switchgrass, powdered wood, algae and waste from poultry processing.The device could be used in small-scale units to provide electricity for developing nations, as well as for larger facilities to provide power where significant quantities of biomass are available.”We have developed a new method that can handle the biomass at room temperature, and the type of biomass that can be used is not restricted — the process can handle nearly any type of biomass,” said Yulin Deng, a professor in Georgia Tech’s School of Chemical and Biomolecular Engineering and the Institute of Paper Science and Technology (IPST). “This is a very generic approach to utilizing many kinds of biomass and organic waste to produce electrical power without the need for purification of the starting materials.”The new solar-induced direct biomass-to-electricity hybrid fuel cell was described February 7, 2014, in the journal Nature Communications.The challenge for biomass fuel cells is that the carbon-carbon bonds of the biomass — a natural polymer — cannot be easily broken down by conventional catalysts, including expensive precious metals, Deng noted. To overcome that challenge, scientists have developed microbial fuel cells in which microbes or enzymes break down the biomass. But that process has many drawbacks: power output from such cells is limited, microbes or enzymes can only selectively break down certain types of biomass, and the microbial system can be deactivated by many factors.Deng and his research team got around those challenges by altering the chemistry to allow an outside energy source to activate the fuel cell’s oxidation-reduction reaction.In the new system, the biomass is ground up and mixed with a polyoxometalate (POM) catalyst in solution and then exposed to light from the sun — or heat. A photochemical and thermochemical catalyst, POM functions as both an oxidation agent and a charge carrier. POM oxidizes the biomass under photo or thermal irradiation, and delivers the charges from the biomass to the fuel cell’s anode. The electrons are then transported to the cathode, where they are finally oxidized by oxygen through an external circuit to produce electricity.”If you mix the biomass and catalyst at room temperature, they will not react,” said Deng. “But when you expose them to light or heat, the reaction begins. The POM introduces an intermediate step because biomass cannot be directly accessed by oxygen.”The system provides major advantages, including combining the photochemical and solar-thermal biomass degradation in a single chemical process, leading to high solar conversion and effective biomass degradation. …


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Theory on origin of animals challenged: Some animals need extremely little oxygen

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One of science’s strongest dogmas is that complex life on Earth could only evolve when oxygen levels in the atmosphere rose to close to modern levels. But now studies of a small sea sponge fished out of a Danish fjord shows that complex life does not need high levels of oxygen in order to live and grow.The origin of complex life is one of science’s greatest mysteries. How could the first small primitive cells evolve into the diversity of advanced life forms that exists on Earth today? The explanation in all textbooks is: Oxygen. Complex life evolved because the atmospheric levels of oxygen began to rise app. 630 — 635 million years ago.However new studies of a common sea sponge from Kerteminde Fjord in Denmark shows that this explanation needs to be reconsidered. The sponge studies show that animals can live and grow even with very limited oxygen supplies.In fact animals can live and grow when the atmosphere contains only 0.5 per cent of the oxygen levels in today’s atmosphere.”Our studies suggest that the origin of animals was not prevented by low oxygen levels,” says Daniel Mills, PhD at the Nordic Center for Earth Evolution at the University of Southern Denmark.Together with Lewis M. Ward from the California Institute of Technology he is the lead author of a research paper about the work in the journal PNAS.A little over half a billion years ago, the first forms of complex life — animals — evolved on Earth. Billions of years before that life had only consisted of simple single-celled life forms. The emergence of animals coincided with a significant rise in atmospheric oxygen, and therefore it seemed obvious to link the two events and conclude that the increased oxygen levels had led to the evolution of animals.”But nobody has ever tested how much oxygen animals need — at least not to my knowledge. …


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#Earth, #Ecology, #Institute, #Marine, #Mills, #Oxygen, #Science, #Technology

Four unknown galaxy clusters containing thousands of galaxies discovered 10 billion light years from Earth

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Four unknown galaxy clusters each potentially containing thousands of individual galaxies have been discovered some 10 billion light years from Earth.An international team of astronomers, led by Imperial College London, used a new way of combining data from the two European Space Agency satellites, Planck and Herschel, to identify more distant galaxy clusters than has previously been possible. The researchers believe up to 2000 further clusters could be identified using this technique, helping to build a more detailed timeline of how clusters are formed.Galaxy clusters are the most massive objects in the universe, containing hundreds to thousands of galaxies, bound together by gravity. While astronomers have identified many nearby clusters, they need to go further back in time to understand how these structures are formed. This means finding clusters at greater distances from Earth.The light from the most distant of the four new clusters identified by the team has taken over 10 billion years to reach us. This means the researchers are seeing what the cluster looked like when the universe was just three billion years old.Lead researcher Dr David Clements, from the Department of Physics at Imperial College London, explains: “Although we’re able to see individual galaxies that go further back in time, up to now, the most distant clusters found by astronomers date back to when the universe was 4.5 billion years old. This equates to around nine billion light years away. Our new approach has already found a cluster in existence much earlier than that, and we believe it has the potential to go even further.”The clusters can be identified at such distances because they contain galaxies in which huge amounts of dust and gas are being formed into stars. This process emits light that can be picked up by the satellite surveys.Galaxies are divided into two types: elliptical galaxies that have many stars, but little dust and gas; and spiral galaxies like our own, the Milky Way, which contain lots of dust and gas. Most clusters in the universe today are dominated by giant elliptical galaxies in which the dust and gas has already been formed into stars.”What we believe we are seeing in these distant clusters are giant elliptical galaxies in the process of being formed,” says Dr Clements.Observations were recorded by the Spectral and Photometric Imaging Receiver (SPIRE) instrument as part of Herschel Multi-tiered Extragalactic Survey (HerMES). Seb Oliver, Head of the HerMES survey said: “The fantastic thing about Herschel-SPIRE is that we are able to scan very large areas of the sky with sufficient sensitivity and image sharpness that we can find these rare and exotic things. …


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#Agency, #Agriculture, #Alzheimer, #Clusters, #Council, #Earth, #European, #Imperialcollege, #Physics, #Technology

Investigating the fiber of our being: How our gut bacteria metabolize complex carbohydrates from fruits, vegetables

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We are all aware of the health benefits of dietary fiber. But what is dietary fiber and how do we metabolize it?Research at the University of Michigan Medical School, the University of York’s Structural Biology Laboratory, and institutions in Canada and Sweden, has begun to uncover how our gut bacteria metabolize the complex dietary carbohydrates found in fruits and vegetables.Trillions of bacteria live in human intestines — there are about ten times more bacterial cells in the average person’s body than human ones. Known as “microbiota,” these bacteria have a vital role to play in human health: they are central to our metabolism and well-being.The research team has uncovered how one group of gut bacteria, known as Bacteroidetes, digest complex sugars known as xyloglucans. These make up to 25 per cent of the dry weight of dietary fruit and vegetables including lettuce, onion, eggplant and tomatoes.In a recent issue of Nature, the researchers reported on a particular gene sequence that allows Bacteroidetes to carry out this function. They show that about 92 per cent of the population harbors bacteria with a variant of the gene sequence, according to a survey of public genome data from 250 adult humans.Understanding how these bacteria digest complex carbohydrates informs studies on a wide range of nutritional issues. These include probiotics (the consumption of ‘beneficial’ micro-organisms as a food supplement) and prebiotics (the consumption of foods or supplements intended to stimulate the production of healthy bacteria in the gut).”Its been appreciated for a long time that our symbiotic gut bacteria provide us with greatly expanded abilities to digest dietary fiber. However, the precise details of how this happens remain largely unexplored,” says co-corresponding author Eric Martens, Ph.D., an assistant professor in the Department of Microbiology & Immunology at the U-M Medical School. Martens is participating in the Host Microbiome Initiative, part of the U-M Medical School’s Strategic Research Initiative.Large-scale genome sequencing efforts, like the Human Microbiome Project, have focused on the community of microorganisms that live in the human gut. But these approaches can only uncover functions that have already been experimentally described, and much of what is sequenced is still unknown.”In this study, we took an empirical approach to decipher how one model gut bacterium digests one type of fiber that is abundant in the foods we eat. We were subsequently able to fit our findings into a much larger picture because of the existing data that the Human Microbiome Project has already gathered. …


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Cortical convolutions controlled in sections: Non-coding DNA sequence affects brain"s characteristic folding, study shows

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Researchers have tied a particular gene to the development of cortical convolutions — the prominent but enigmatic folds covering the surface of the human brain. Their discovery should shed some light on these characteristic contours, which have been the subject of wild speculation for ages, and perhaps also provide a better understanding of how such brain ridges form, how they evolved from our pre-human ancestors and, ultimately, how they influence brain function.The exact role of cortical convolutions remains unknown, but theories have abounded. (Some, for example, have suggested that the folds act as the body’s cooling system and others have even proposed that Albert Einstein’s genius could have been traced to a single cortical fold on his brain.)Now, leveraging advances that permit a closer look at how these folds develop, research published in the 14 February issue of Science shows that a mutation affecting GPR56 causes cortical convolutions around the brain’s Sylvian fissure — a particularly deep indentation — to develop thinner and more convoluted than usual. The finding, which suggests that genes may assert control over the brain’s physical folding on a section-by-section basis, provides insight into the mysterious cortical development process.”There is already a list of genetic mutations that cause abnormal neocortical folding, which can be used for prenatal testing,” explained Byoung-il Bae from the Division of Genetics and Genomics at Boston Children’s Hospital and Harvard Medical School in Boston, Massachusetts, one of the lead authors of the Science report. “We intend to add this mutation to some of the panels.”Bae and colleagues from around the world investigated the genomes of five individuals with abnormalities on Broca’s area, or the language center of the brain. These study participants were from three different families — one Turkish and two Irish-American — and they suffered from refractory seizures as well as intellectual and language difficulties.The researchers found that all five patients harbored a mutation on a particular regulatory element that influences the GPR56 gene. Such regulatory DNA doesn’t code for any proteins itself but promotes the expression of genes elsewhere on the genome. Geneticists have long-suspected that such non-coding regions of the genome could play important roles in evolution. To observe the specific effects of the GPR56 “promoter” DNA sequence, Bae and his team used genetically modified mice.They discovered that low expression of GPR56 (gauged by low levels of mRNA) decreases the production of neuroprogenitor cells — those that will eventually give rise to neurons — around Broca’s area and the Sylvian fissure. By contrast, overexpression of the gene boosts the production of such progenitor cells in that region. …


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Is zinc the missing link for osteoarthritis therapies?

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Osteoarthritis is a leading cause of disability, characterized by the destruction of cartilage tissue in joints, but there is a lack of effective therapies because the underlying molecular causes have been unclear. A study published by Cell Press February 13th in the journal Cell reveals that osteoarthritis-related tissue damage is caused by a molecular pathway that is involved in regulating and responding to zinc levels inside of cartilage cells. A protein called ZIP8 transports zinc inside these cells, setting off a cascade of molecular events that result in the destruction of cartilage tissue in mice. The findings could lead to a new generation of therapies for osteoarthritis.”No evidence available to date clearly indicated that zinc plays a causal role in osteoarthritis,” says senior study author Jang-Soo Chun of the Gwangju Institute of Science and Technology. “In our study, we revealed the entire series of molecular events in the osteoarthritis zinc pathway, from zinc influx into cells to cartilage destruction.”When the cartilage breaks down in osteoarthritis, the bones rub together, causing pain, swelling, and stiffness. This tissue destruction is caused by proteins called matrix-degrading enzymes, which are produced by cartilage cells and are the key culprits responsible for degrading the extracellular matrix — the structural support system that surrounds cells and holds them together. Because matrix-degrading enzymes require zinc to function, Chun and his team suspected that zinc levels inside of cartilage cells may play a role in osteoarthritis.To test this idea, the researchers first examined cartilage from osteoarthritis patients as well as a mouse model of the disease. They found abnormally high levels of a protein called ZIP8, which is embedded in the plasma membrane of cartilage cells and is involved in transporting zinc inside of these cells from the outside environment. Zinc influx through ZIP8 activated a protein called metal-regulatory transcription factor-1 (MTF1), which in turn increased levels of matrix-degrading enzymes in cartilage cells. Through genetic experiments in mice, the researchers showed that this zinc-ZIP8-MTF1 pathway plays a key role in causing osteoarthritis-related cartilage destruction.”Our findings suggest that local depletion of zinc or pharmacological inhibition of ZIP8 function or MTF1 activity in cartilage tissue would be effective therapeutic approaches for the treatment of osteoarthritis,” Chun says. …


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Primitive artificial cell turned into complex biological materials

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Imagine starting from scratch with simple artificial microscopic building blocks and ending up with something much more complex: living systems, novel computers or every-day materials. For decades scientists have pursued the dream of creating artificial building blocks that can self-assemble in large numbers and reassemble to take on new tasks or to remedy defects. Now researchers have taken a step forward to make this dream into a reality.”The potential of such new human-made systems is almost limitless, and many expect these novel materials to become the foundation of future technologies,” says Dr. Maik Hadorn from Department of Chemistry and Applied Biosciences at ETH Zrich, who conducted the research as a postdoctoral research fellow at University of Southern Denmark (SDU).Over the last three years he and the colleagues Eva Boenzli, Kristian T. Srensen and Martin M. Hanczyc from the Center for Fundamental Living Technology (FLinT) at SDU have worked on the challenges of making primitive building blocks assemble and turn into something functional.”We used short DNA strands as smart glue to link preliminary stages of artificial cells (called artificial vesicles) to engineer novel tissue-like structures,” says Dr. Maik Hadorn.As part of the EU-sponsored project MATCHIT (MATrix for CHemical Information Technology) Dr. Maik Hadorn and coworkers have earlier showed that short DNA strands can guide the self-assembly process of artificial vesicles; that two types of artificial vesicles can be linked in a way predefined by the person conducting the experiment, and that assembled structures can be reassembled, when triggered externally.In their most recent scientific article, published in Langmuir in December 2013, the researchers from SDU, in collaboration with colleagues from Italy and Japan, not only increased the complexity of the self-assembled structures that are now composed of several types of artificial vesicles — they also loaded one vesicle type with a basic cellular machinery derived from bacterial cells. This enabled these vesicles to translate an encapsulated genetic blueprint into a functional protein.Put together the researchers have managed to engineer controlled assemblies that are visible to the naked eye and that resemble natural tissues in their architecture as well as in their functionalities.Methods of constructing simple artificial structures have been known for decades, but only the use of DNA strands that act as a smart glue has allowed the researchers to overcome shortcomings of precedent methods and to engineer higher-order structures of predefined and programmable architecture.”As the artificial vesicles resemble natural cells both in size and composition, they are an ideal starting point for a multitude of applications. One application can be a temporal support for wound healing: A wound may be covered with assemblies of vesicles that are tailored in a patient specific manner. …


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Looking back to the cradle of our universe: Astronomers spot what may be one of most distant galaxies known

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NASA’s Spitzer and Hubble Space Telescopes have spotted what might be one of the most distant galaxies known, harkening back to a time when our universe was only about 650 million years old (our universe is 13.8 billion years old). The galaxy, known as Abell2744 Y1, is about 30 times smaller than our Milky Way galaxy and is producing about 10 times more stars, as is typical for galaxies in our young universe.The discovery comes from the Frontier Fields program, which is pushing the limits of how far back we can see into the distant universe using NASA’s multi-wavelength suite of Great Observatories. Spitzer sees infrared light, Hubble sees visible and shorter-wavelength infrared light, and NASA’s Chandra X-ray Observatory sees X-rays. The telescopes are getting a boost from natural lenses: they peer through clusters of galaxies, where gravity magnifies the light of more distant galaxies.The Frontier Fields program will image six galaxy clusters in total. Hubble images of the region are used to spot candidate distant galaxies, and then Spitzer is needed to determine if the galaxies are, in fact, as far as they seem. Spitzer data also help determine how many stars are in the galaxy.These early results from the program come from images of the Abell 2744 galaxy cluster. The distance to this galaxy, if confirmed, would make it one of the farthest known. Astronomers say it has a redshift of 8, which is a measure of the degree to which its light has been shifted to redder wavelengths due to the expansion of our universe. The farther a galaxy, the higher the redshift. The farthest confirmed galaxy has a redshift of more than 7. …


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