aruvam

Blind Patient Reads Words Stimulated Directly Onto Retina: Neuroprosthetic Device Uses Implant ...

Fri, 23 Nov 2012 15:43:16 +0100

Grid of electrons directly implanted on the retina. (Credit: Second Sight)

For the very first time researchers have streamed braille patterns directly into a blind patient's retina, allowing him to read four-letter words accurately and quickly with an ocular neuroprosthetic device. The device, the Argus II, has been implanted in over 50 patients, many of who can now see color, movement and objects. It uses a small camera mounted on a pair of glasses, a portable processor to translate the signal from the camera into electrical stimulation, and a microchip with electrodes implanted directly on the retina.

The study was authored by researchers at Second Sight, the company who developed the device, and has been published in Frontiers in Neuroprosthetics on the 22nd of November.

"In this clinical test with a single blind patient, we bypassed the camera that is the usual input for the implant and directly stimulated the retina. Instead of feeling the braille on the tips of his fingers, the patient could see the patterns we projected and then read individual letters in less than a second with up to 89% accuracy," explains researcher Thomas Lauritzen, lead author of the paper.

Similar in concept to successful cochlear implants, the visual implant uses a grid of 60 electrodes -- attached to the retina -- to stimulate patterns directly onto the nerve cells. For this study, the researchers at Second Sight used a computer to stimulate six of these points on the grid to project the braille letters. A series of tests were conducted with single letters as well as words ranging in length from two letters up to four. The patient was shown each letter for half a second and had up to 80% accuracy for short words.

"There was no input except the electrode stimulation and the patient recognized the braille letters easily. This proves that the patient has good spatial resolution because he could easily distinguish between signals on different, individual electrodes." says Lauritzen.

According to Silvestro Micera at EPFL's Center for Neuroprosthetics and scientific reviewer for the article, "this study is a proof of concept that points to the importance of clinical experiments involving new neuroprosthetic devices to improve the technology and innovate adaptable solutions."

Primarily for sufferers of the genetic disease Retinitis Pigmentosa (RP), the implant Argus II has been shown to restore limited reading capability of large conventional letters and short words when used with the camera. While reading should improve with future iterations of the Argus II, the current study shows how the Argus II could be adapted to provide an alternative and potentially faster method of text reading with the addition of letter recognition software. This ability to perform image processing in software prior to sending the signal to the implant is a unique advantage of Argus II.

Promotional video that explains device:http://www.youtube.com/watch?v=bBzMWVOTFi8&feature=related

9.2-Million-Year-Old Rhino Skull Preserved by Instant 'Cooking to Death' in Volcanic Ash

Thu, 22 Nov 2012 14:25:05 +0100

The fossil, found in Turkey, is thought to be that of a large two-horned rhino common in the Eastern Mediterranean region during that period. (Credit: Reconstruction by Maëva J. Orliac; Antoine et al. (2012) A Rhinocerotid Skull Cooked-to-Death in a 9.2 Ma-Old Ignimbrite Flow of Turkey. PLoS ONE doi:10.1371/journal.pone.0049997)

Less than 2% of Earth's fossils are preserved in volcanic rock, but researchers have identified a new one: the skull of a rhino that perished in a volcanic eruption 9.2 million years ago.

The find is described in a paper published Nov. 21 in the open access journal PLOS ONE by Pierre-Olivier Antoine and colleagues from the University of Montpellier, France.

The fossil, found in Turkey, is thought to be that of a large two-horned rhino common in the Eastern Mediterranean region during that period. According to the researchers, unusual features of the preserved skull suggest that the animal was 'cooked to death' at temperatures that may have approached 500° C, in a volcanic flow similar to that of the eruption of Mt. Vesuvius in Italy in 79 A.D.

The rhino's grisly death was near-instantaneous, and followed by severe dehydration in the extreme heat of the eruption. As the researchers describe its end, "the body was baked under a temperature approximating 400°C, then dismembered within the pyroclastic flow, and the skull separated from body." The flow of volcanic ash then moved the skull about 30 km north of the eruption site, where it was discovered by the four member research team.

Although other researchers have previously identified fossils of soft-bodied organisms preserved in volcanic ash, organic matter near an active volcanic eruption is usually quickly destroyed by the high temperatures, making a fossil such as this one extremely rare.

Hot Gas Bridges Galaxy Cluster Pair

Tue, 20 Nov 2012 17:06:47 +0100

Galaxy clusters connected by gas bridge. (Credit: Sunyaev–Zel’dovich effect: ESA Planck Collaboration; optical image: STScI Digitized Sky Survey)

ESA's Planck space telescope has made the first conclusive detection of a bridge of hot gas connecting a pair of galaxy clusters across 10 million light-years of intergalactic space.

Planck's primary task is to capture the most ancient light of the cosmos, the Cosmic Microwave Background, or CMB. As this faint light traverses the Universe, it encounters different types of structure including galaxies and galaxy clusters -- assemblies of hundreds to thousands of galaxies bound together by gravity.

If the CMB light interacts with the hot gas permeating these huge cosmic structures, its energy distribution is modified in a characteristic way, a phenomenon known as the Sunyaev-Zel'dovich (SZ) effect, after the scientists who discovered it.

This effect has already been used by Planck to detect galaxy clusters themselves, but it also provides a way to detect faint filaments of gas that might connect one cluster to another.

In the early Universe, filaments of gaseous matter pervaded the cosmos in a giant web, with clusters eventually forming in the densest nodes.

Much of this tenuous, filamentary gas remains undetected, but astronomers expect that it could most likely be found between interacting galaxy clusters, where the filaments are compressed and heated up, making them easier to spot.

Planck's discovery of a bridge of hot gas connecting the clusters Abell 399 and Abell 401, each containing hundreds of galaxies, represents one such opportunity.

The presence of hot gas between the billion-light-year-distant clusters was first hinted at in X-ray data from ESA's XMM-Newton, and the new Planck data confirm the observation.

It also marks Planck's first detection of inter-cluster gas using the SZ effect technique.

By combining the Planck data with archival X-ray observations from the German satellite Rosat, the temperature of the gas in the bridge is found to be similar to the temperature of the gas in the two clusters -- on the order of 80 million degrees Celsius.

Early analysis suggests the gas could be mixture of the elusive filaments of the cosmic web mixed with gas originating from the clusters.

A more detailed analysis and the possible detection of gas bridges connecting other clusters will help to provide a more conclusive answer.

Breakthrough Nanoparticle Halts Multiple Sclerosis in Mice, Offers Hope for Other ...

Mon, 19 Nov 2012 12:06:55 +0100

A biodegradable nanoparticle turns out to be the perfect vehicle to stealthily deliver an antigen that tricks the immune system into stopping its attack on myelin and halt a model of relapsing remitting multiple sclerosis (MS) in mice, researchers report. (Credit: © mgkuijpers / Fotolia)

In a breakthrough for nanotechnology and multiple sclerosis, a biodegradable nanoparticle turns out to be the perfect vehicle to stealthily deliver an antigen that tricks the immune system into stopping its attack on myelin and halt a model of relapsing remitting multiple sclerosis (MS) in mice, according to new Northwestern Medicine research.

The new nanotechnology also can be applied to a variety of immune-mediated diseases including Type 1 diabetes, food allergies and airway allergies such as asthma.

In MS, the immune system attacks the myelin membrane that insulates nerves cells in the brain, spinal cord and optic nerve. When the insulation is destroyed, electrical signals can't be effectively conducted, resulting in symptoms that range from mild limb numbness to paralysis or blindness. About 80 percent of MS patients are diagnosed with the relapsing remitting form of the disease.

The Northwestern nanotechnology does not suppress the entire immune system as do current therapies for MS, which make patients more susceptible to everyday infections and higher rates of cancer. Rather, when the nanoparticles are attached to myelin antigens and injected into the mice, the immune system is reset to normal. The immune system stops recognizing myelin as an alien invader and halts its attack on it.

"This is a highly significant breakthrough in translational immunotherapy," said Stephen Miller, a corresponding author of the study and the Judy Gugenheim Research Professor of Microbiology-Immunology at Northwestern University Feinberg School of Medicine. "The beauty of this new technology is it can be used in many immune-related diseases. We simply change the antigen that's delivered."

"The holy grail is to develop a therapy that is specific to the pathological immune response, in this case the body attacking myelin," Miller added. "Our approach resets the immune system so it no longer attacks myelin but leaves the function of the normal immune system intact."

The nanoparticle, made from an easily produced and already FDA-approved substance, was developed by Lonnie Shea, professor of chemical and biological engineering at Northwestern's McCormick School of Engineering and Applied Science.

"This is a major breakthrough in nanotechnology, showing you can use it to regulate the immune system," said Shea, also a corresponding author. The paper will be published Nov. 18 in the journal Nature Biotechnology.

Miller and Shea are also members of the Robert H. Lurie Comprehensive Cancer Center of Northwestern University. In addition, Shea is a member of the Institute for BioNanotechnology in Medicine and the Chemistry of Life Processes Institute.

Clinical Trial for Ms Tests Same Approach -- With Key Difference

The study's method is the same approach now being tested in multiple sclerosis patients in a phase I/II clinical trial -- with one key difference. The trial uses a patient's own white blood cells -- a costly and labor intensive procedure -- to deliver the antigen. The purpose of the new study was to see if nanoparticles could be as effective as the white blood cells as delivery vehicles. They were.

The Big Nanoparticle Advantage for Immunotherapy

Nanoparticles have many advantages; they can be readily produced in a laboratory and standardized for manufacturing. They would make the potential therapy cheaper and more accessible to a general population. In addition, these nanoparticles are made of a polymer called Poly(lactide-co-glycolide) (PLG), which consists of lactic acid and glycolic acid, both natural metabolites in the human body. PLG is most commonly used for biodegradable sutures.

The fact that PLG is already FDA approved for other applications should facilitate translating the research to patients, Shea noted. Miller and Shea tested nanoparticles of various sizes and discovered that 500 nanometers was most effective at modulating the immune response.

"We administered these particles to animals who have a disease very similar to relapsing remitting multiple sclerosis and stopped it in its tracks," Miller said. "We prevented any future relapses for up to 100 days, which is the equivalent of several years in the life of an MS patient."

Shea and Miller also are currently testing the nanoparticles to treat Type one diabetes and airway diseases such as asthma.

Nanoparticles Fool Immune System

In the study, researchers attached myelin antigens to the nanoparticles and injected them intravenously into the mice. The particles entered the spleen, which filters the blood and helps the body dispose of aging and dying blood cells. There, the particles were engulfed by macrophages, a type of immune cell, which then displayed the antigens on their cell surface. The immune system viewed the nanoparticles as ordinary dying blood cells and nothing to be concerned about. This created immune tolerance to the antigen by directly inhibiting the activity of myelin responsive T cells and by increasing the numbers of regulatory T cells which further calmed the autoimmune response.

"The key here is that this antigen/particle-based approach to induction of tolerance is selective and targeted. Unlike generalized immunosuppression, which is the current therapy used for autoimmune diseases, this new process does not shut down the whole immune system," said Christine Kelley, National Institute of Biomedical Imaging and Bioengineering director of the division of Discovery Science and Technology at the National Institutes of Health, which supported the research. "This collaborative effort between expertise in immunology and bioengineering is a terrific example of the tremendous advances that can be made with scientifically convergent approaches to biomedical problems."

"We are proud to share our expertise in therapeutics development with Dr. Stephen Miller's stellar team of academic scientists," said Scott Johnson, CEO, president and founder of the Myelin Repair Foundation. "The idea to couple antigens to nanoparticles was conceived in discussions between Dr. Miller's laboratory, the Myelin Repair Foundation's drug discovery advisory board and Dr. Michael Pleiss, a member of the Myelin Repair Foundation's internal research team, and we combined our efforts to focus on patient-oriented, clinically relevant research with broad implications for all autoimmune diseases. Our unique research model is designed to foster and extract the innovation from the academic science that we fund and transition these technologies to commercialization. The overarching goal is to ensure this important therapeutic pathway has its best chance to reach patients, with MS and all autoimmune diseases."

Himalayan Glaciers Will Shrink by Almost 10 Percent, Even If Temperatures Hold Steady

Sat, 17 Nov 2012 03:23:45 +0100

The Lunana region of Bhutan. (Credit: Image courtesy of Brigham Young University)

Come rain or shine, or even snow, some glaciers of the Himalayas will continue shrinking for many years to come.

The forecast by Brigham Young University geology professor Summer Rupper comes after her research on Bhutan, a region in the bull's-eye of the monsoonal Himalayas. Published in Geophysical Research Letters, Rupper's most conservative findings indicate that even if climate remained steady, almost 10 percent of Bhutan's glaciers would vanish within the next few decades. What's more, the amount of melt water coming off these glaciers could drop by 30 percent.

Rupper says increasing temperatures are just one culprit behind glacier retreat. A number of climate factors such as wind, humidity, precipitation and evaporation can affect how glaciers behave. With some Bhutanese glaciers as long as 13 miles, an imbalance in any of these areas can take them decades to completely respond.

"These particular glaciers have seen so much warming in the past few decades that they're currently playing lots of catch up," Rupper explains.

In fact, snowfall rates in Bhutan would need to almost double to avoid glacier retreat, but it's not a likely scenario because warmer temperatures lead to rainfall instead of snow. If glaciers continue to lose more water than they gain, the combination of more rain and more glacial melt will increase the probability of flooding -- which can be devastating to neighboring villages.

"Much of the world's population is just downstream of the Himalayas," Rupper points out. "A lot of culture and history could be lost, not just for Bhutan but for neighboring nations facing the same risks."

To illustrate the likelihood of such an outcome, Rupper took her research one moderate step further. Her results show if temperatures were to rise just 1 degree Celsius, the Bhutanese glaciers would shrink by 25 percent and the annual melt water would drop by as much as 65 percent. With climate continuing to warm, such a prediction is not altogether unlikely, especially given the years it can take for glaciers to react to change.

To make more precise predictions for Bhutan, Rupper and BYU graduate students Landon Burgener and Josh Maurer joined researchers from Columbia University, the Lamont-Doherty Earth Observatory, NASA and Bhutan's Department of Hydro-Meteorological Services. Together, they trekked through rainforests and barren cliffs to reach some of the world's most remote blocks of ice. There they placed a weather station and glacier monitoring equipment that can be used to gather real-time data in the months and years to follow.

"It took seven days just to get to the target glacier," Rupper recounts, having returned in October. "For our pack animals, horsemen and guides, that terrain and elevation are a way of life, but I'll admit the westerners in the group were a bit slower-moving."

Rupper's forecasts and fieldwork are among the first to look at glaciers in Bhutan, and the government hopes to use her research to make long-term decisions about the nation's water resources and flooding hazards.

"They could potentially have a better idea of where best to fortify homes or build new power plants," Rupper says. "Hopefully, good science can lead to good engineering solutions for the changes we're likely to witness in the coming decades."

Not What You Consciously Thought: How We Can Do Math Problems and Read Phrases Nonconsciously

Wed, 14 Nov 2012 14:23:56 +0100

Can we actually read words and phrases and solve multi-step mathematical problems without our having consciously been aware of them? A team in the Psychology Department at the Hebrew University has conducted a series of experiments that give a positive answer: people can read and do math nonconsciously.

The results constitute a challenge to existing theories of unconscious processes, that maintain that reading and solving math problems -- two prime examples of complex, rule-based operations -- require consciousness.

The conclusions of the Hebrew University team were published this week inthe Proceedings of the National Academy of Sciences. The research team, headed by Dr. Ran Hassin, included graduate students Asael Sklar, Ariel Goldstein, Nir Levy and Roi Mandel, as well as Dr. Anat Maril.

To present sentences and equations unconsciously, the researchers used a cutting-edge technique called Continuous Flash Suppression (CFS). In CFS, one eye is exposed to a series of rapidly changing images, while the other is simultaneously exposed to a constant image. The rapid changes in the one eye dominate consciousness, so that the image presented to the other eye is not experienced consciously. Using this technique, more than 270 students at the Hebrew University were exposed to sentences and arithmetic problems.

In one set of experiments using this technique, participants were asked to pronounce numbers that appeared on a computer's screen. These numbers were preceded with unconscious arithmetic equations. The results of the experiments showed that participants could more quickly pronounce the conscious number if it had been the result of the unconscious equation. For example, when 9-5-1 was shown nonconsciously, the participants were faster in pronouncing 3 than 4, even though they did not consciously see the equation.

In another set of experiments reported in the PNAS paper, participants were nonconsciously exposed to a number of short verbal expressions that remained on screen until participants could say that they saw them. (In the meantime, the other eye was exposed to the rapidly flashing images). The results showed that negative verbal expressions (e.g., human trafficking) or unusual phrases (e.g., the bench ate a zebra) became conscious to the viewers before more positive expressions (e.g., ironed shirt and more usual phrases (e.g., the lion ate a zebra), indicating a definite "pickup" by the unconscious of something negative and out of the ordinary.

"These results show that the humans can perform complex, rule-based operations unconsciously, contrary to existing models of consciousness and the unconscious," say the researchers.

"Therefore," said Dr. Hassin, "current theories of the unconscious processes and human consciousness need to be revised. These revisions would bring us closer to solving one of the biggest scientific mysteries of the 21^st century: What are the functions of human consciousness."

Making a Better Invisibility Cloak

Mon, 12 Nov 2012 14:31:12 +0100

The first functional "cloaking" device reported by Duke University electrical engineers in 2006 worked like a charm, but it wasn't perfect. Now a member of that laboratory has developed a new design that ties up one of the major loose ends from the original device.

These new findings could be important in transforming how light or other waves can be controlled or transmitted. Just as traditional wires gave way to fiber optics, the new meta-material could revolutionize the transmission of light and waves.

Because the goal of this type of research involves taming light, a new field of transformational optics has emerged. The results of the Duke experiments were published online Nov. 11 in the journal Nature Materials.

The Duke team has extensive experience in creating "meta-materials," human-made objects that have properties often absent in natural ones. Structures incorporating meta-materials can be designed to guide electromagnetic waves around an object, only to have them emerge on the other side as if they had passed through an empty volume of space, thereby cloaking the object.

"In order to create the first cloaks, many approximations had to be made in order to fabricate the intricate meta-materials used in the device," said Nathan Landy, a graduate student working in the laboratory of senior investigator David R. Smith, William Bevan Professor of electrical and computer engineering at Duke's Pratt School of Engineering.

"One issue, which we were fully aware of, was loss of the waves due to reflections at the boundaries of the device," Landy said. He explained that it was much like reflections seen on clear glass. The viewer can see through the glass just fine, but at the same time the viewer is aware the glass is present due to light reflected from the surface of the glass. "Since the goal was to demonstrate the basic principles of cloaking, we didn't worry about these reflections."

Landy has now reduced the occurrence of reflections by using a different fabrication strategy. The original cloak consisted of parallel and intersecting strips of fiberglass etched with copper. Landy's cloak used a similar row-by-row design, but added copper strips to create a more complicated -- and better performing -- material. The strips of the device, which is about two-feet square, form a diamond-shape, with the center left empty.

When any type of wave, like light, strikes a surface, it can be either reflected or absorbed, or a combination of both. In the case of earlier cloaking experiments, a small percentage of the energy in the waves was absorbed, but not enough to affect the overall functioning of the cloak.

The cloak was naturally divided into four quadrants. Landy explained the "reflections" noted in earlier cloaks tended to occur along the edges and corners of the spaces within and around the meta-material.

"Each quadrant of the cloak tended to have voids, or blind spots, at their intersections and corners with each other," Landy said. "After many calculations, we thought we could correct this situation by shifting each strip so that it met its mirror image at each interface.

"We built the cloak, and it worked," he said. "It split light into two waves which traveled around an object in the center and re-emerged as the single wave with minimal loss due to reflections."

Landy said this approach could have more applications than just cloaks. For example, meta-materials can "smooth out" twists and turns in fiber optics, in essence making them seem straighter. This is important, Landy said, because each bend attenuates the wave within it.

The researchers are now working to apply the principles learned in the latest experiments to three dimensions, a much greater challenge than in a two-dimensional device.

Nathan Landy with cloaking device. (Credit: Duke University Photography)

Habitable Planet: New Super-Earth in Six-Planet System May Be Just Right to Support Life

Thu, 08 Nov 2012 15:13:08 +0100

A new super-Earth planet that may have an Earth-like climate and be just right to support life has been discovered around a nearby star by an international team of astronomers, led by Mikko Tuomi, University of Hertfordshire, and Guillem Anglada-Escude, University of Goettingen.

The new super-Earth planet exists in the habitable zone of a nearby star and is part of a six-planet system. The system was previously thought to contain three planets in orbits too close to the star to support liquid water. By avoiding fake signals caused by stellar activity, the researchers have identified three new super-Earth planet candidates also in orbit.

Mikko Tuomi said: "We pioneered new data analysis techniques including the use of the wavelength as a filter to reduce the influence of activity on the signal from this star. This significantly increased our sensitivity and enabled us to reveal three new super-Earth planets around the star known as HD 40307, making it into a six-planet system."

Of the new planets, the one of greatest interest is the one with the outermost orbit from the star -- with a mass at least seven times of the Earth. Its orbit around the host star is at a similar distance to Earth's orbit around our Sun, so it receives a similar amount of energy from the star as the Earth receives from the Sun -- increasing the probability of it being habitable. This is where the presence of liquid water and stable atmospheres to support life is possible and, more importantly, the planet is likely to be rotating on its own axis as it orbits around the star creating a daytime and night-time effect on the planet which would be better at creating an Earth-like environment.

Guillem Angla-Escude said: "The star HD 40307, is a perfectly quiet old dwarf star, so there is no reason why such a planet could not sustain an Earth-like climate."

Hugh Jones, University of Hertfordshire, added: "The longer orbit of the new planet means that its climate and atmosphere may be just right to support life. Just as Goldilocks liked her porridge to be neither too hot nor too cold but just right, this planet or indeed any moons that it has lie in an orbit comparable to Earth, increasing the probability of it being habitable."

Earlier this year, the Kepler spacecraft found a planet with a similar orbit. However, Kepler 22d is located 600 light years from Earth, whereas this new super-Earth planet known as HD 40307g is much closer being located at 42 light years from Earth.

Mikko Tuomi carried out this work as a member of the European science network RoPACS (Rocky Planets Around Cool Stars) -- an initiative with a research focus on the search for planets around cool stars. RoPACS has pan-European membership and is led from the University of Hertfordshire by David Pinfield, who commented: "Discoveries like this are really exciting, and such systems will be natural targets for the next generation of large telescopes, both on the ground and in space."

Star Formation Slumps to 1/30th of Its Peak

Wed, 07 Nov 2012 07:17:52 +0100

This diagram indicates the changing ‘GDP’ of the Universe over time. The new results indicate that, measured by mass, the production rate of stars has dropped by 97% since its peak 11 billion years ago. (Credit: D. Sobral)

While parts of the world experience economic hardship, a team of Portuguese, UK, Japanese, Italian and Dutch astronomers has found an even bigger slump happening on a cosmic scale. In the largest ever study of its kind, the international team of astronomers has established that the rate of formation of new stars in the Universe is now only 1/30th of its peak and that this decline is only set to continue.

The team, led by David Sobral of the University of Leiden in the Netherlands, publish their results in the journal Monthly Notices of the Royal Astronomical Society.

The accepted model for the evolution of the Universe predicts that stars began to form about 13.4 billion years ago, or around three hundred million years after the Big Bang. Many of these first stars are thought to have been monsters by today's standards, and were probably hundreds of times more massive than our Sun. Such beasts aged very quickly, exhausted their fuel, and exploded as supernovae within a million years or so. Lower mass stars in contrast have much longer lives and last for billions of years.

Much of the dust and gas from stellar explosions was (and is still) recycled to form newer and newer generations of stars. Our Sun, for example, is thought to be a third generation star, and has a very typical mass by today's standards. But regardless of their mass and properties, stars are key ingredients of galaxies like our own Milky Way. Unveiling the history of star formation across cosmic time is fundamental to understanding how galaxies form and evolve.

In the new study, scientists used the UK Infrared Telescope (UKIRT), the Very Large Telescope (VLT) and the Subaru telescope to carry out the most complete survey ever made of star-forming galaxies at different distances, with around ten times the data of any previous effort. With the range of distances, the time taken for the light to reach us means that we see identically selected galaxies at different periods in the history of the universe, so we can really understand how conditions change over time.

By looking at the light from clouds of gas and dust in these galaxies where stars are forming, the team are able to assess the rate at which stars are being born. They find that the production of stars in the universe as a whole has been continuously declining over the last 11 billion years, being 30 times lower today than at its likely peak, 11 billion years ago.

Dr Sobral comments: "You might say that the universe has been suffering from a long, serious "crisis": cosmic GDP output is now only 3% of what it used to be at the peak in star production!"

'If the measured decline continues, then no more than 5% more stars will form over the remaining history of the cosmos, even if we wait forever. The research suggests that we live in a universe dominated by old stars. Half of these were born in the 'boom' that took place between 11 and 9 billion years ago and it took more than five times as long to produce the rest. "The future may seem rather dark, but we're actually quite lucky to be living in a healthy, star-forming galaxy which is going to be a strong contributor to the new stars that will form.

'Moreover, while these measurements provide a sharp picture of the decline of star-formation in the Universe, they also provide ideal samples to unveil an even more fundamental mystery which is yet to be solved: why?"

How Underground Rodent Wards Off Cancer: Second Mole Rat Species Has Different Mechanism for ...

Tue, 06 Nov 2012 12:00:12 +0100

Biologists at the University of Rochester have determined how blind mole rats fight off cancer -- and the mechanism differs from what they discovered three years ago in another long-lived and cancer-resistant mole rat species, the naked mole rat.

The team of researchers, led by Professor Vera Gorbunova and Assistant Professor Andrei Seluanov, found that abnormally growing cells in blind mole rats secrete the interferon beta protein, which causes those cells to rapidly die. Seluanov and Gorbunova hope the discovery will eventually help lead to new cancer therapies in humans. Their findings are being published this week in the Proceedings of the National Academy of Sciences.

Blind mole rats and naked mole rats -- both subterranean rodents with long life spans -- are the only mammals never known to develop cancer. Three years ago, Seluanov and Gorbunova determined the anti-cancer mechanism in the naked mole rat. Their research found that a specific gene -- p16 -- makes the cancerous cells in naked mole rats hypersensitive to overcrowding, and stops them from proliferating when too many crowd together.

"We expected blind mole rats to have a similar mechanism for stopping the spread of cancerous cells," said Seluanov. "Instead, we discovered they've evolved their own mechanism."

Gorbunova and Seluanov made their discovery by isolating cells from blind mole rats and forcing them to proliferate in culture beyond what occurs in the animal. After dividing approximately 15-20 times, all of the cells in the culture dish died rapidly. The researchers determined that the rapid death occurred because the cells recognized their pre-cancerous state and began secreting a suicidal protein, called interferon beta. The precancerous cells died by a mechanism which kills both abnormal cells and their neighbors, resulting in a "clean sweep."

"Not only were the cancerous cells killed off, but so were the adjacent cells, which may also be prone to tumorous behavior," said Seluanov.

"While people don't use the same cancer-killing mechanism as blind mole rats, we may be able to combat some cancers and prolong life, if we could stimulate the same clean sweep reaction in cancerous human cells," said Gorbunova.

The research team also included Christopher Hine, Xiao Tian, and Julia Ablaeva in Rochester, Andrei Gudkov at Roswell Park Cancer Institute in Buffalo, NY, and Eviatar Nevo at the University of Haifa in Israel.

Gorbunova and Seluanov say they next want to find out exactly what triggers the secretion of interferon beta after cancerous cells begin proliferating in blind mole rats.

Gorbunova believes the anti-cancer mechanism is an adaptation to subterranean life. "Blind mole rats spend their lives in underground burrows protected from predators," said Gorbunova. "Living in this environment, they could perhaps afford to evolve a long lifespan, which includes developing efficient anti-cancer defenses."

A blind mole rat is shown on the background of dying necrotic blind mole rat cells. (Credit: University of Rochester)