Amazing Science
Follow
485.3K views | +470 today
Amazing Science
Amazing science facts - 3D_printing • aging • AI • anthropology • art • astronomy • bigdata • bioinformatics • biology • biotech • chemistry • computers • cosmology • education • environment • evolution • future • genetics • genomics • geosciences • green_energy • history • language • map • material_science • math • med • medicine • microscopy • nanotech • neuroscience • paleontology • photography • photonics • physics • postings • robotics • science • technology • video
Your new post is loading...
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Modified Cold Sore Virus Shrinks Melanoma Tumors, Amgen Says

Modified Cold Sore Virus Shrinks Melanoma Tumors, Amgen Says | Amazing Science | Scoop.it

A genetically modified version of herpes simplex virus type 1, the same virus that causes cold sores, shrank tumors of the deadly skin cancer melanoma in a clinical trial, according to Amgen, which is developing the experimental cancer treatment.

 

Patients in the trial were in the late stages of the disease, and were either being treated with a drug called GM-CSF or the new virus. Sixteen percent of the patients in the group that got the virus, known as talimogene laherparepvec, saw their tumors shrink completely or partially for at least six months. That compares to two percent of the control group. There was a trend toward the virus helping patients live longer, but the difference is not yet statistically significant.Amgen says that it may become so later this year, and those results are likely to be far more important in determining the future of the treatment.

 

Amgen purchased the company that developed the virus, Biovex, in 2011 for $425 million in cash and a commitment to pay up to $575 million if Biovex’s medicines hit certain milestones. If the Biovex anti-cancer virus is indeed a potent cancer fighter, it could help get investors excited about Amgen. It might also benefit Merck, because Amgen’s former research chief, Roger Perlmutter, has just agreed to take over running the research labs there, and this might reflect on his ability to make smart acquisitions.

 

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

97% of family doctors in the UK admitted to giving placebos to patients at least once

97% of family doctors in the UK admitted to giving placebos to patients at least once | Amazing Science | Scoop.it

In a poll, 97% of 783 GPs admitted that they had recommended a sugar pill or a treatment with no established efficacy for the ailment their patient came in with.

 

The Royal College of GPs says there is a place for placebos in medicine.

But they warn that some sham treatments may be inappropriate and could cause side effects or issues such as drug resistance.

 

For example, one of the placebo treatments identified in the study was antibiotics for suspected viral infections.

 

This is not about doctors deceiving patients”. Antibiotics are powerless against viruses and doctors are told not to use them.

 

About one in 10 of the GPs in the study said they had given a patient a sugar pill or an injection of salty water rather than a real medicine at some time in their career. One in 100 of them said they did this at least once a week.

 

Almost all of the GPs said they had provided patients with treatments, like supplements, probiotics and complementary medicines, that were unproven for their medical condition. Three-quarters said they offered unproven treatments on a daily or weekly basis.

 

Dr. Jeremy Howick, co-author of the study that was carried out by the University of Oxford and the University of Southampton, said: "This is not about doctors deceiving patients. "The study shows that placebo use is widespread in the UK, and doctors clearly believe that placebos can help patients."

 

The GPs in the study said they used placebos either because patients requested treatment or to reassure patients. Half said they told their patients that the therapy had helped other patients without specifically telling them that they were prescribing a placebo.

 

Dr Clare Gerada, chairwoman of the Royal College of GPs, said it was perfectly acceptable to use a placebo as long as it did not cause harm and was not expensive. "Lots of doctors use them and they can help people.

"If you think about it, a kiss on the cheek when you fall over is a placebo.

"But there are risks. Not all of the placebo treatments that the researchers looked at in this study are inert. If you take too many vitamins, for example, some can cause harm."

 

She said fobbing off patients with an ineffectual treatment was never acceptable. "But admitting to your patient that you do not know exactly what is going on, but that a therapy might help is."

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Origami sphere: DNA folding takes a fresh direction

Origami sphere: DNA folding takes a fresh direction | Amazing Science | Scoop.it

The intricate art of DNA origami has been given a fresh twist. Researchers at Arizona State University in Tempe have managed to coerce a single strand of DNA to fold back on itself to form an array of two- and three-dimensional nanostructures.

 

DNA origami involves using scaffolding to guide a single strand of DNA as it folds up to form a shape. The Arizona team, led by Hao Yan, managed to create more intricate shapes than have been possible so far, by using scaffolding made up of cross-like structures of two DNA strands nearly at right angles to each other.

 

Similar cross-shaped structures, called Holliday junctions, are not new. But it had been thought impossible to link them together to make a stable scaffold because the charge of the DNA molecules was always mismatched.

 

Yan and his team overcame this problem by tweaking the way they assembled their scaffold so that the junctions became slightly ‘twisted’. The result was that junctions could link together to form a waffle-like gridiron structure that is “surprisingly very stable”, Yan says.

Using this, the team was able to guide the formation of not only two-dimensional DNA structures but also three-dimensional spheres and screw-like shapes. The scaffold and the various structures it can produce are published in Science today.

 

Yan hopes that DNA origami can now become more useful, perhaps building three-dimensional ‘cages’ to hold drugs and so deliver them to the specific place they are needed in the body.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

US report: How to cut U.S. gasoline use in half by 2030

US report: How to cut U.S. gasoline use in half by 2030 | Amazing Science | Scoop.it
A new report from the National Academy of Sciences shows how it can be done, but no single technology or policy will get us there.

 

Those are audacious goals. But if the United States ever plans to deal seriously with climate change, the transportation sector will have to change drastically. And the National Academy of Sciences report concludes that no one single policy or technology will do the trick.

 

Case in point: In the past few years, the Obama administration has enacted a series of ambitious corporate average fuel economy  standards that will require new cars to get around 54.5 miles per gallon by 2025. (That will translate into about 35.4 miles per gallon on the road.) That sounds impressive, but the NAS study concludes that current standards aren’t enough to hit even that 2030 goal for oil use.

 

In fact, the report argues, it’s tough to find any single technology that can cut oil use in half by 2030 on its own. Making conventional cars more efficient won’t do it. A major push on electric vehicles won’t do it. The only things likely to work are a massive switch over to natural-gas vehicles (which would, in turn, make it much harder to hit the greenhouse-gas goals) or a combination of efficiency, electric vehicles, and advanced biofuels.

 

What the NAS is doing here is estimating the impact of each technology “if it is pursued vigorously.” And it found that each technology, on its own, has some promising upsides and some limitations. Better efficiency, for instance: The report found that there’s enormous potential to make conventional gasoline vehicles more efficient, from engine and drivetrain improvements to lighter vehicles. Over the past few  years, automakers have started adopting many of these tactics, such as gasoline direct injection. The NAS report estimates that conventional cars could realistically average 74 miles per gallon in 2050 and hybrids 94 mpg.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Controlled double-slit electron diffraction used to demonstrate Feynman's original thought experiment

Controlled double-slit electron diffraction used to demonstrate Feynman's original thought experiment | Amazing Science | Scoop.it
Double-slit diffraction is a corner stone of quantum mechanics. It illustrates key features of quantum mechanics: interference and the particle-wave duality of matter. In 1965, Richard Feynman presented a thought experiment to show these features.

 

Richard Feynman described electron diffraction as a phenomenon 'which has in it the heart of quantum mechanics. In reality, it contains the only mystery'. He went on to describe a thought experiment for which he stated 'that you should not try to set up' because 'the apparatus would have to be made on an impossibly small scale to show the effects we are interested in'. He used these effects to help illustrate the phenomena of wave–particle duality, which is a postulate that all particles exhibit both wave and particle properties. The effects he described were: the relations between electron probability distributions from single- and double-slits, and observation of single particle diffraction. In this paper we report both control over the individual slits to observe probability distributions from both single- and double-slits, and the build-up of a diffraction pattern at single electron detection rates to achieve the full realization of Feynman's thought experiment. We use the term build-up to refer to the measurement of the cumulative spatial detection pattern as a function of time.

 

The general perception is that the electron double-slit experiment has already been performed. This is true in the sense that Jönsson demonstrated diffraction from single, double, and multiple (up to five) micro-slits, but he could not observe single particle diffraction, nor close individual slits. In two separate landmark experiments, individual electron detection was used to produce interference patterns; however, biprisms were used instead of double-slits. First, Pozzi recorded the interference patterns at varying electron beam densities. Then, Tonomura recorded the positions of individual electron detection events and used them to produce the well known build-up of an interference pattern. It is interesting to point out that the build up of a double-slit diffraction pattern has been called 'The most beautiful experiment in physics', while the build-up for a true double-slit has, up to now, never been reported.

 

More recently, electron diffraction was demonstrated with single- and double-slits using focused ion beam (FIB) milled nano-slits. In addition, one single slit in a double-slit was closed by FIB induced deposition. This process is not reversible, so observation of the electron probability distribution through both single-slits could not be done. Also, using a fast-readout pixel detector, electrons were recorded one at a time and stacked into a final diffraction pattern, but intermediate spatial patterns were not reported.

 

Feynman's original thought experiment contained two parts. The first involved observing probability distributions in three scenarios: electrons traveling through slit 1 with slit 2 closed (P1); electrons traveling through slit 2 with slit 1 closed (P2); and electrons traveling through both slits (P12). These scenarios illustrate the quantum mechanical superposition principle, i.e. the wave properties, and can be demonstrated with control of the slits (see Figure). The second part of the thought experiment was the observation of individual electrons associated with detection 'clicks'. This illustrates that a quantum mechanical electron wave cannot be thought of as comprising multiple electrons, i.e. the particle properties, which can be demonstrated with the build-up of the diffraction pattern.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

NASA: Herschel Discovers Some of the Youngest Stars Ever Seen

NASA: Herschel Discovers Some of the Youngest Stars Ever Seen | Amazing Science | Scoop.it
Astronomers have found some of the youngest stars ever seen, thanks to the Herschel space observatory, a European Space Agency mission with important NASA contributions.

 

stronomers have found some of the youngest stars ever seen, thanks to the Herschel space observatory, a European Space Agency mission with important NASA contributions. Observations from NASA's Spitzer Space Telescope and the Atacama Pathfinder Experiment (APEX) telescope in Chile, a collaboration involving the Max Planck Institute for Radio Astronomy in Germany, the Onsala Space Observatory in Sweden, and the European Southern Observatory in Germany, contributed to the findings.

 

Dense envelopes of gas and dust surround the fledging stars known as protostars, making their detection difficult. The 15 newly observed protostars turned up by surprise in a survey of the biggest site of star formation near our solar system, located in the constellation Orion. The discovery gives scientists a peek into one of the earliest and least understood phases of star formation.

 

"Herschel has revealed the largest ensemble of such young stars in a single star-forming region," said Amelia Stutz, lead author of a paper to be published in The Astrophysical Journal and a postdoctoral researcher at the Max Planck Institute for Astronomy in Heidelberg, Germany. "With these results, we are getting closer to witnessing the moment when a star begins to form."

 

Of NASA's 15 newly discovered protostars, 11 possess very red colors, meaning their light output trends toward the low-energy end of the electromagnetic spectrum. This output indicates the stars are still embedded deeply in a gaseous envelope, meaning they are very young. An additional seven protostars previously seen by Spitzer share this characteristic.

 

Together, these 18 budding stars comprise only five percent of the protostars and candidate protostars observed in Orion. That figure implies the very youngest stars spend perhaps 25,000 years in this phase of their development, a mere blink of an eye considering a star like our sun lives for about 10 billion years.

 

Researchers hope to document chronologically each stage of a star's development rather like a family album, from before birth to early infancy, when planets also take shape.

 

"With these recent findings, we add an important missing photo to the family album of stellar development," said Glenn Wahlgren, Herschel Program Scientist at NASA Headquarters in Washington. "Herschel has allowed us to study stars in their infancy."

 

Herschel is a European Space Agency mission, with science instruments provided by a consortia of European institutes with important participation by NASA. NASA's Herschel Project Office is based at the agency's Jet Propulsion Laboratory in Pasadena, Calif. JPL is a division of the California Institute of Technology, Pasadena.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

When mind is at rest, brain sends backward signals to clear useless old information

When mind is at rest, brain sends backward signals to clear useless old information | Amazing Science | Scoop.it

When the mind is at rest, the electrical signals by which brain cells communicate appear to travel in reverse, wiping out unimportant information in the process, but sensitizing the cells for future sensory learning, according to a study of rats conducted by researchers at the National Institutes of Health.

 

The finding has implications not only for studies seeking to help people learn more efficiently, but also for attempts to understand and treat post-traumatic stress disorder―in which the mind has difficulty moving beyond a disturbing experience.

 

During waking hours, brain cells, or neurons, communicate via high-speed electrical signals that travel the length of the cell. These communications are the foundation for learning. As learning progresses, these signals travel across groups of neurons with increasing rapidity, forming circuits that work together to recall a memory.

 

It was previously known that, during sleep, these impulses were reversed, arising from waves of electrical activity originating deep within the brain. In the current study, the researchers found that these reverse signals weakened circuits formed during waking hours, apparently so that unimportant information could be erased from the brain. But the reverse signals also appeared to prime the brain to relearn at least some of the forgotten information. If the animals encountered the same information upon awakening, the circuits re-formed much more rapidly than when they originally encountered the information.

 

“The brain doesn’t store all the information it encounters, so there must be a mechanism for discarding what isn’t important,” said senior author R. Douglas Fields, Ph.D., head of the Section on Nervous System Development and Plasticity at the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), the NIH institute where the research was conducted. “These reverse brain signals appear to be the mechanism by which the brain clears itself of unimportant information.”

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Scientists discover new species of crocodile newt in Vietnam

Scientists discover new species of crocodile newt in Vietnam | Amazing Science | Scoop.it

Researchers have discovered a new species of Vietnamese salamander that looks like it was birthed from an abyssal volcano. Found tucked away in Tokyo's National Museum of Nature and Science, the scientists described the species in the new edition ofCurrent Herpetology. Coal-black with orange-tinted toes, the new crocodile newt (in the genus Tylototriton) was determined to be a new species when it showed morphological and genetic differences from near relatives. Despite its remarkable appearance, the researchers say these are typical colors for crocodile newts.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Whole brain cellular-level activity mapping in one second

Whole brain cellular-level activity mapping in one second | Amazing Science | Scoop.it

Neuroscientists at Howard Hughes Medical Institute have mapped the activity of nearly all the neurons in a vertebrate brain at cellular resolution, with signficant implications for neuroscience research and projects like the proposed Brain Activity Map (BAM).

 

Fast volumetric imaging of the larval zebrafish brain with light-sheet microscopy (credit: Misha B Ahrens, Philipp J Keller/Nature Methods)

The researchers used high-speed light sheet microscopy to image the activity of 80% of the neurons in the brain (which is composed of ~100,000 neurons) of a fish larva at 0.8 Hz (an image every 1.3 seconds), with single-cell resolution.

 

This represents the first technology that achieves whole brain imaging of a vertebrate brain at cellular resolution with speeds that approximate neural activity patterns and behavior, as Nature Methodsmethagora blog noted.

The authors saw correlated activity patterns at the cellular level that spanned large areas of the brain — pointing to the existence of broadly distributed functional circuits.

 

The next steps will be to determine the causal role that these circuits play in behavior — something that will require improvements in the methods for 3D optogenetics, the blog said. Obtaining the detailed anatomical map of these circuits will also be key to understand the brain’s organization at its deepest level.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

The Mariana trench, deepest point in the ocean is teeming with life

The Mariana trench, deepest point in the ocean is teeming with life | Amazing Science | Scoop.it

Hollywood director James Cameron found little evidence of life when hedescended nearly 11,000 metres to the deepest point in the world's oceans last year. If only he had taken a microscope and looked just a few centimetres deeper.

 

Ronnie Glud at the University of Southern Denmark in Odense, and his colleagues, have discovered unusually high levels of microbial activity in the sediments at the site of Cameron's dive – Challenger Deep at the bottom of the western Pacific's Mariana Trench.

 

Glud's team dispatched autonomous sensors and sample collectors into the trench to measure microbial activity in the top 20 centimetres of sediment on the sea bed. The pressure there is almost 1100 times greater than at the surface. Finding food, however, is an even greater challenge than surviving high pressures for anything calling the trench home.

 

Any nourishment must come in the form of detritus falling from the surface ocean, most of which is consumed by other organisms on the way down. Only 1 per cent of the organic matter generated at the surface reaches the sea floor's abyssal plains, 3000 to 6000 metres below sea level. So what are the chances of organic matter making it even deeper, into the trenches that form when one tectonic plate ploughs beneath another?

 

Surprisingly, the odds seem high. Glud's team compared sediment samples taken from Challenger Deep and a reference site on the nearby abyssal plain. The bacteria at Challenger Deep were around 10 times as abundant as those on the abyssal plain, with every cubic centimetre of sediment containing 10 million microbes. The deep microbes were also twice as active as their shallower kin.

 

These figures make sense, says Glud, because ocean trenches are particularly good at capturing sediment. They are broad as well as deep, with a steep slope down to the deepest point, so any sediment falling on their flanks quickly cascades down to the bottom in muddy avalanches. Although the sediment may contain no more than 1 per cent organic matter, so much of it ends up at Challenger Deep that the level of microbial activity shoots up.

 

"There is much more than meets the eye at the bottom of the sea," says Hans Røy, at Aarhus University in Denmark. Last year, he studied seafloor sediments below the north Pacific gyre – an area that, unlike Challenger Deep, is almost devoid of nutrients. Remarkably, though, even here Røy found living microbes.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Red blood cell production relies on white blood cell help

Red blood cell production relies on white blood cell help | Amazing Science | Scoop.it

Red blood cell production in the bone marrow is a precarious process. Too few RBCs and you can become anemic; too many and you could be suffering from polycythemia vera, a rare, so-called ‘myeloproliferative’ genetic disorder marked by an abnormally high RBC count. Now, researchers have identified a surprising player in the regulation of RBC production under these disease conditions. Reporting online today in Nature Medicine, two independent teams describe the pivotal role of macrophages—amoeba-like white blood cells responsible for digesting harmful foreign microbes and removing old or dying cells—for generating RBCs in both anemic and over-proliferative conditions.

 

In one study, geneticist Stefano Rivella and his colleagues at the Weill Cornell Medical College in New York administered a drug that selectively kills macrophages in a mouse model of polycythemia vera. In these mice, RBCs are generated at almost twice the normal amount, leading to viscous blood, enlarged organs and increased risk for strokes and heart disease. The drug, called clodronate, appeared to cure these symptoms, however, drastically lowering macrophage population and bringing RBC counts back to normal levels compared with a control group of animals treated with saline.

 

These findings were independently confirmed by Paul Frenette, a stem cell biologist at the Albert Einstein College of Medicine, also in New York. His team used a genetically modified mouse in which macrophages expressed a gene that made them vulnerable to a toxin and arrived at similar conclusions. “When we depleted macrophages in this disease, we actually corrected the disease,” Frenette says. “Maybe this could be a new therapy for this type of disease, which is unexpected.”

 

Rivella and his group also studied beta-thalassemia, another inherited blood disorder characterized by lowered RBC counts and severe anemia. Paradoxically, RBC precursor cells are actually overproduced in this disease, but they never fully mature and subsequently build up in the spleen and liver, leading to organ enlargement. When treated with clodronate, however, genetically modified mice with a beta-thalassemia-like condition showed statistically significant increased RBC counts. Rivella chalks this effect up to reduced precursor cell numbers and organ size, allowing better circulation of healthy cells. “Take out the macrophages and the ability of RBC precursors to expand and proliferate is decreased,” he says.

 

Interestingly, when normal mice were macrophage-depleted, there were no observable effects on RBC levels. Both Frenette and Rivella believe that this indicates macrophages modulate RBC production only during stress or abnormal conditions. The precise mechanisms for this new stress-related role remain opaque, although Frenette’s group showed evidence that an adhesion molecule known as VCAM1 and a bone marrow protein known as BMP 4 could play a part.

 

For now, patients suffering from disorders such as polycythemia vera and beta-thalassemia will have to wait until these mechanisms are fully understood. Macrophage depletion in both studies was temporary, as cessation of treatment led to macrophage and symptom recovery. In addition, macrophage depletion can have severe consequences in immunity, bone formation and many other systems. Clodronate “is a really great drug to do these experiments, but it’s not something I’d suggest to patients,” says Rivella.

On the flipside, boosting macrophage levels could prove beneficial in some settings. For instance, Frenette’s group gave mice bone marrow transplants and showed that wiping out macrophage levels significantly delayed RBC recovery. The finding, Frenette says, “would suggest that methods to improve macrophage functional recovery might be useful in a situation such as bone marrow transplantation where you need to make more red blood cells faster.”

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Astronomers Detect Extremely Rare Triple Quasar

Astronomers Detect Extremely Rare Triple Quasar | Amazing Science | Scoop.it

By combining multiple telescope observations and advanced modeling, a multinational team of astronomers has discovered an extremely rare triple quasar system – only the second such object ever found.

 

Quasars are powerful sources of energy that sit in the center of a galaxy, surrounding a black hole. In systems with multiple quasars, the bodies are held together by gravity and are believed to be the product of galaxies colliding.

 

It is very difficult to observe triplet quasar systems, because of observational limits that prevent researchers from differentiating multiple nearby bodies from one another at astronomical distances.

 

The team combined observations from ESO’s New Technology Telescope at La Silla, Chile, and from the Calar Alto Observatory in Spain with advanced modelling. This enabled them to find the quasar, labeled QQQ J1519+0627.

 

The light from this object has traveled 9 billion light years to reach us, which means the light was emitted when the Universe was only a third of its current age.

 

Advanced analysis confirmed that what the team found was indeed three distinct sources of quasar energy and that the phenomenon is extremely rare.

 

“Honing our observational and modeling skills and finding this rare stellar phenomenon will help us understand how cosmic structures assemble in our universe and the basic processes by which massive galaxies form,” said Dr Michele Fumagalli from Princeton University and Carnegie Observatories.

 

Two members of the triplet are closer to each other than the third. This means that the system could have been formed by interaction between the two adjacent quasars, but was probably not triggered by interaction with the more-distant third quasar. Furthermore, no evidence was seen of any ultra-luminous inferred galaxies, which is where quasars are commonly found. As a result, the astronomers propose that this triplet quasar system is part of some larger structure that is still undergoing formation.

 

“Further study will help us figure out exactly how these quasars came to be and how rare their formation is,” said lead author Dr Emanuele Farina of the Universita degli Studi dell’Insubria and the Universit`a degli Studi di Milano-Bicocca.

 

 

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Breakthrough Research Shows Chemical Reactions in Real Time

Breakthrough Research Shows Chemical Reactions in Real Time | Amazing Science | Scoop.it

The ultrafast, ultrabright X-ray pulses of the Linac Coherent Light Source (LCLS) have enabled unprecedented views of a catalyst in action, an important step in the effort to develop cleaner and more efficient energy sources.

 

Scientists at the U.S. Department of Energy's (DOE) SLAC National Accelerator Laboratory used LCLS, together with computerized simulations, to reveal surprising details of a short-lived early state in a chemical reaction occurring at the surface of a catalyst sample. The study offers important clues about how catalysts work and launches a new era in probing surface chemistry as it happens.

 

"To study a reaction like this in real time is a chemist's dream," said Anders Nilsson, deputy director for the Stanford and SLAC SUNCAT Center for Interface Science and Catalysis and a leading author in the research, published March 15 in Science. "We are really jumping into the unknown."

 

In the LCLS experiment, researchers looked at a simple reaction in a crystal composed of ruthenium, a catalyst that has been extensively studied, in reaction with carbon monoxide gas. The scientists zapped the crystal's surface with a conventional laser, which caused carbon monoxide molecules to begin to break away. They then probed this state of the reaction using X-ray laser pulses, and observed that the molecules were temporarily trapped in a near-gas state and still interacting with the catalyst.

 

"We never expected to see this state," Nilsson said. "It was a surprise."

 

Not only was the experiment the first to confirm the details of this early stage of the reaction, it also found an unexpectedly high share of molecules trapped in this state for far longer than what was anticipated, raising new questions about the atomic-scale interplay of chemicals that will be explored in future research.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Potential Treatment for Ebola and Rabies Discovered

Potential Treatment for Ebola and Rabies Discovered | Amazing Science | Scoop.it

A molecule related to plant-derived compounds known as indoline alkaloids appears to block crucial elements of replication in nonsegmented, negative sense (NNS) RNA viruses, an order that includes such unsavory members as Ebola, rabies and measles. The molecule, CMLDBU3402, could become the basis for an effective, broad-spectrum therapy to treat NNS viruses, according to the study, published today in the journal Chemistry & Biology.

 

There are currently no effective therapies or vaccines for many NNS viruses, several of which are highly contagious and have high mortality rates. Ebola, for example, can kill 90 percent of those infected.

 

Researchers in the study first identified a number of chemotypes that had not previously been screened for potential activity against NNS viruses. They identified several molecules within this group that appeared to inhibit infection in cells exposed to Ebola or another NNS virus, vesicular stomatitis, which primarily affects cattle, horses and swine.

 

The newly discovered compounds are illustrated as green molecules “blocking” the spread of orange Ebola virus virions from an infected cell. Image created by Claire Marie Filone and John Connor; Ebola virus micrograph by Chris Reed at USAMRIID.

 

The most promising compound in the study — CMLDBU3402 — appeared to target viral RNA-dependent RNA polymerase (RdRp). RdRp is required for many aspects of RNA synthesis, which is how one virus replicates to become many. The enzyme is produced by all NNS viruses and inhibiting it appears to block transcription, preventing the spread of infection in the host.

 

Because RdRp is found in all NNS viruses and is necessary for replication, researchers believe molecule CMLDBU3402 can be used to develop a treatment for the entire virus order, potentially wiping out not just Ebola and newer NNS discoveries such as the Nipah and Hendra viruses, but also old scourges including rabies, mumps and measles.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Big Bang inflation model confirmation indicates ‘infinite number of universes’ exist

Big Bang inflation model confirmation indicates ‘infinite number of universes’ exist | Amazing Science | Scoop.it

Scientists just announced the exciting results of the European Space Agency’s Planck space probe experiment, which observed conditions about the universe in the milliseconds after the Big Bang by looking at background radiation in the sky. They found that scientists’ theory of inflation—that the universe expanded in a sudden rush in a fraction of a second after the Big Bang—was actually correct. Which is pretty incredible, because the theory had been based sheerly on abstract math. Lo and behold, the first observable data about the moments directly after the Big Bang show the inflation model is exactly what actually happened.

 

“We’ve uncovered a fundamental truth of the universe,” said George Efstathiou of Cambridge University, who announced the results. They also uncovered some additional little details, like the universe is about 80 million years older than scientists had thought, and filled with slightly more regular matter and less dark matter than they’d thought.

 

So you’d think all the scientists would be psyched, right? Pats on the back, champagne all around. Especially the guys who camee up with the inflation theory in the first place—it’s widely thought they could win a Nobel Prize.

Except those guys are troubled.

 

Associated Press reports: Efstathiou said the pioneers of inflation theory should start thinking about their own Nobel prizes. Two of those theorists – Paul Steinhardt of Princeton and Andreas Albrecht of University of California Davis – said before the announcement that they were sort of hoping that their inflation theory would not be bolstered.

 

That’s because taking inflation a step further leads to a sticky situation: An infinite number of universes.

 

In order for inflation theory to work—and it was confirmed as being a reality yesterday—”that split-second of expansion may not stop elsewhere like it does in the observable universe,” the scientists say. “That means,” notes AP, “there are places where expansion is zooming fast, with an infinite number of universes that stretch to infinity.”

 

So the idea of an infinite number of universes existing in parallel to our own universe is now no longer the stuff of sci-fi, but the most likely reality as interpreted by our most advanced science.

 

“You can get very, very strange answers to problems when you start thinking about what different observers might see in different universes,” Efstathiou said.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Engineered immune cells battle acute leukemia into retreat

Engineered immune cells battle acute leukemia into retreat | Amazing Science | Scoop.it

Modified T cells seek out and destroy blood cancer.

 

Genetically engineered immune cells can drive an aggressive type of leukemia into retreat, a small clinical trial suggests. The results of the trial — done in five patients with acute lymphoblastic leukemia and represent the latest success for a 'fringe' therapy in which a type of immune cell called T cells are extracted from a patient, genetically modified, and then reinfused back. In this case, the T cells were engineered to express a receptor for a protein on other immune cells, known as B cells, found in both healthy and cancerous tissue.


When reintroduced into the patients, the tricked T cells quickly homed in on their targets. “All of our patients very rapidly cleared the tumor,” says Michel Sadelain, a researcher at the Memorial Sloan-Kettering Cancer Center in New York and an author of the study. The treatment “worked much faster than we thought”.

The technique has already shown promise against chronic leukemia, but there were doubts about whether it could take on the faster-growing acute lymphoblastic leukemia, a tenacious disease that kills more than 60% of those afflicted.  

Carl June, an immunologist at the University of Pennsylvania in Philadelphia and a pioneer in engineering T cells to fight cancer, says that he is surprised that the method worked so well against such a swift-growing cancer. The next step, he says, is to move the technique out of the ‘boutique’ academic cancer centres that developed it and into multicentre clinical trials.

 

Oncologist Renier Brentjens, also at Memorial Sloan-Kettering Cancer Center, remembers the day that he had to tell one of the patients in the trial that the weeks of high-dose chemotherapy the 58-year-old man had endured had not worked after all. “It was painful to have that conversation,” says Brentjens. “He tells me now it was the worst news he has ever heard in his life.”

 

Another month in the hospital on intensive chemotherapy drugs did nothing to help. By the time the man started the trial, 70% of his bone marrow was tumour. Brentjens, Sadelain and their colleagues then extracted T cells from the patient and engineered them to express a ‘chimeric antigen receptor’, or CAR, that would target cells expressing a protein called CD19. Because CD19 is found on both healthy and cancerous B cells, the engineered T cells were unable to discriminate between the two. However, patients can live without B cells.


By two weeks after the procedure, the patient was showing signs of improvement. The treatment had driven his cancer into remission — as it did for the other four patients in the trial — so he became eligible for a bone-marrow transplant. A hundred days later, he is doing well, says Brentjens. Four of the five patients were well enough to receive transplants; the remaining patient relapsed and was ineligible.

 

Pharmaceutical firms have tended to be wary of the CAR technique because it is technically challenging, must be personalized to the patient and faces an untested path to regulatory approval, says Steven Rosenberg, head of the tumour immunology section at the National Cancer Institute in Bethesda, Maryland.

 

But this seems to be changing. Rosenberg points to a collaboration formed in August last year between June's group and the drug giant Novartis, as well as the launch of several small CAR-focused biotechnology firms. And Sadelein says that he is an investigator on a trial with the Dana-Farber Cancer Institute in Boston, Massachusetts, to test whether the technique can be exported to other treatment centers, among other outcomes.

more...
Elias Açaf's comment, June 1, 2013 10:17 AM
so interesting !
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Big Bang’s afterglow shows universe is 80 million years older than scientists thought

Big Bang’s afterglow shows universe is 80 million years older than scientists thought | Amazing Science | Scoop.it

A new examination of what is essentially the universe’s birth certificate allows astronomers to tweak the age, girth and speed of the cosmos, more secure in their knowledge of how it evolved, what it’s made of and its ultimate fate.

 

Sure, the universe suddenly seems to be showing its age, now calculated at 13.8 billion years — 80 million years older than scientists had thought. It’s got about 3 percent more girth — technically it’s more matter than mysterious dark energy — and it is expanding about 3 percent more slowly.

 

But with all that comes the wisdom for humanity. Scientists seem to have gotten a good handle on the Big Bang and what happened just afterward, and may actually understand a bit more about the cosmic question of how we are where we are.

 

All from a baby picture of fossilized light and sound.The snapshot from a European satellite had scientists from Paris to Washington celebrating a cosmic victory of knowledge Thursday — basic precepts that go back all the way to Einstein and relativity.

 

The Planck space telescope mapped background radiation from the early universe — now calculated at about 13.8 billion years old. The results bolstered a key theory called “inflation,” which says the universe burst from subatomic size to its vast expanse in a fraction of a second just after the Big Bang that created the cosmos.

 

“We’ve uncovered a fundamental truth of the universe,” said George Efstathiou, director of the Kavli Institute for Cosmology at the University of Cambridge who announced the Planck findings in Paris. “There’s less stuff that we don’t understand by a tiny amount.”

 

The map of the universe’s evolution — in sound echoes and fossilized light going back billions of years — reinforces some predictions made decades ago solely on the basis of mathematical concepts.

 

“We understand the very early universe potentially better than we understand the bottom of our oceans,” said Bob Nichols, director of the Institute of Cosmology and Gravitation at the University of Portsmouth in Britain. “We as humanity put a satellite into space, we predicted what it should see and saw it.”

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Researchers publish final version of full Neanderthal genome

Researchers publish final version of full Neanderthal genome | Amazing Science | Scoop.it

In 2010, Dr. Svante Pääbo and his colleagues presented the first draft version of the Neandertal genome from data collected from three bones found in a cave in Croatia. They have now used a toe bone excavated in 2010 in Denisova Cave in southern Siberia to generate a high-quality genome from a single Neandertal individual.

 

The Leipzig team has used sensitive techniques they have developed over the past two years to sequence every position in the genome about 50 times over, using DNA extracted from 0.038 grams of the toe bone. The analysis of the genome together with partial genome sequences from other Neandertals, and the genome from a small finger bone discovered in the same cave, shows that the individual is closely related to other Neandertals in Europe and western Russia (see Figure).

 

Remarkably, Neandertals and their relatives, Denisovans, were both present in this unique cave in the Altai Mountains on the border between Russia, China, Mongolia and Kazakhstan. In the 2010 draft version of the Neandertal genome, each position was determined, on average, once. In the now-completed version of the genome every position was determined on average 50 times over. This allows even the small differences between the copies of genes that this Neandertal individual inherited from its mother and father to be distinguished. Today, the Leipzig group makes the entire Neandertal genome sequence available for the scientific community over the internet. "The genome is of very high quality", says Dr. Kay Prüfer, who coordinates the analyses of the genome in Leipzig. "It matches the quality of the Denisovan genome, presented last year, and is as good as or even better than the multiple present-day human genomes available to date."

 

"We are in the process of comparing this Neandertal genome to the Denisovan genome as well as to the draft genomes of other Neandertals. We will gain insights into many aspects of the history of both Neandertals and Denisovans and refine our knowledge about the genetic changes that occurred in the genomes of modern humans after they parted ways with the ancestors of Neandertals and Denisovans" says Pääbo. The group will present a paper describing the genome later this year. "But we make the genome sequence freely available now to allow other scientists to profit from it even before it is published" says Pääbo. The project is made possible by financing from the Max Planck Society and is part of efforts since almost 30 years by Dr. Pääbo's group to study ancient DNA. The toe bone was discovered by Professor Anatoly Derevianko and Professor Michael Shunkov from the Russian Academy of Sciences in 2010 during their excavations at Denisova Cave, a unique archaeological site which contains cultural layers indicating that human occupation at the site started up to 280,000 years ago.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Jagged ice blades may threaten future landing on Jupiter's icy moon Europa

Jagged ice blades may threaten future landing on Jupiter's icy moon Europa | Amazing Science | Scoop.it

Jupiter's icy moon Europa is a prime target for future space missions as it harbours a buried ocean that could have the right conditions for life.

But attempts to land may face a major hazard: jagged "blades" of ice up to 10m long.

 

A major US conference has heard the moon may have ideal conditions for icy spikes called "penitentes" to form. Scientists would like to send a lander down to sample surface regions where water wells up through the icy crust.

These areas could allow a robotic probe to sample a proxy for ocean water that lies several kilometres deep.

 

Details of the penitentes theory were announced as scientists outlined another proposal to explore the jovian moon with robotic spacecraft.

 

On Earth, these features (so named because of their resemblance to the pointed caps worn by "penitents" in Easter processions around the Spanish-speaking world) form in high altitude regions such as the Andes. Here, the air is both cold and dry, allowing ice to sublimate (turn from a solid into vapour without passing through a liquid phase).

 

Penitentes begin to form when irregularities in the surface of the snow are enhanced by the Sun's energy. These furrows then act as a trap for solar radiation, and, as they deepen, the tall peaks are left behind.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

DNA reveals giant squid is one single species and had brush with death

DNA reveals giant squid is one single species and had brush with death | Amazing Science | Scoop.it
Genetic uniformity shows legendary kraken to be remarkably vulnerable.

 

The fearsome sea monster of Greek and Norse tales — and the creature that fought Captain Nemo in 20,000 Leagues Under the Sea — was once driven close to extinction, gene sequencing suggests. The genetic uniformity of giant squid across distant oceans hints at a past evolutionary bottleneck, but also at low resiliency toward future crises.

 

The finding comes from an analysis of tissue samples from 43 giant squid (Architeuthis spp.) from around the world. The samples came mostly from dead squid that had been found washed up on beaches or floating on the ocean surface, although a few came from animals that were accidentally caught by deep-sea trawlers.

 

When the researchers looked closely at the mitochondrial DNA of the creatures, they noticed something remarkable. Irrespective of where they came from — be it be it California, Japan, South Africa, New Zealand or somewhere else — the squid were genetically very similar.

 

In fact, the diversity of Architeuthis is lower than that for any other marine animal, except one — the basking shark Cetorhinus maximus, whose current population is thought to have rebounded from a small number of individuals. At first, says Thomas Gilbert, a geneticist at the University of Copenhagen and an author of the study, “When we found that the global genetic diversity of the giant squid was this low, we figured we had made an error.” But then the team checked their numbers again and saw that they were correct.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Flash memory chip built out of single-atom-thick components

Flash memory chip built out of single-atom-thick components | Amazing Science | Scoop.it
Graphene and molybdenum disulfide layers make up most of the working parts.

 

The basic outline of a flash memory device involves two electrodes that feed current through a semiconductor within the device. When a negative voltage is sent across a device from a control electrode, electrons are able to feed into a reservoir that retains the charge; reversing the voltage allows them to escape. The presence of the electrons in the reservoir can be read out by sending current through the semiconductor.

 

To build a compact version of the device, the authors of the new paper (who are based in Lausanne, Switzerland) started with two sheets of graphene layered on some silicon, separated by a small gap. These served as the electrodes, with the device itself acting as a bridge between them. The next layer on top of that was the semiconductor, formed by a single-molecule-thick sheet of molybdenum disulfide. Above that, a layer of an insulator that allows electrons to tunnel through it separated the conductor from the charge reservoir. To hold the charges, the authors used a few layers of graphene. That was topped by a bit more insulator and another electrode that acted to control the device, setting it to read or erase.

 

The insulator used in this work wasn't a single atom thick (although insulators of this sort are known) and the graphene charge reservoir was several layers thick, so there were clearly a number of layers involved. But still, this is a very thin device, and can potentially be made even thinner. The manufacturing technique could use some improvements as well, given that one of the steps involved finding individual layers using an optical microscope.

 

In any case, the devices worked. Applying a positive voltage to the control electrode allowed charge to accumulate in the graphene layers, and its presence could be read out based on the current flowing through the device. Reversing the voltage across the control electrode erased the device. They went through 120 write/erase cycles, and the device still functioned. They also left the device unpowered for a bit, and found that while its storage did decay a bit, it only decayed very slowly. Based on the rate, they expect that, after 10 years, 30 percent of the original charge would still be present.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Targeting B-Raf kinase in melanomas

Targeting B-Raf kinase in melanomas | Amazing Science | Scoop.it

Melanoma is a type of skin cancer. It arises from specialized pigmented cells in our body known as melanocytes that are responsible for the production of melanin, a pigment responsible for skin and hair color. Because most melanoma cells still make melanin, melanoma tumors are usually brown or black. It accounts for 4% of all skin cancers; however, it is responsible for the largest numbers of skin cancer related death in the world. In the US, according to the national cancer institute, estimated new cases and deaths from melanoma in 2013 would be 76,690 and 9,480 respectively.

 

Several studies using molecular profiling and genomic sequencing have shown that melanoma is a disease of a heterogeneous group of tumors, and its progression is driven by specific oncogenic mutations. In 2002, Davies et al. first reported the presence of B-RAF somatic missense mutations in 66% of malignant melanomas. RAF (Rapidly growing Fibrosarcoma) protein is a serine/thereonine kinase. Three members of this kinase family are A-RAF, B-RAF, and C-RAF. These serine/threonine protein kinases, downstream of the membrane-bound small G protein RAS, are components of the mitogen activtated protein kinase (MAPK) signal transduction pathway. With closely overlapping functions, all members of the RAF family are associated with the activation of the MAPK pathway. Activation of the MAPK pathway has been associated with uncontrolled growth and drug resistance in several tumors. Researchers have identified over 50 distinct mutations in the B-RAF gene so far. However, most of these mutations are extremely rare. The most common mutation in melanoma, accounting for 90% of all B-RAF mutations, is the V600E mutation that occurs as a result of substitution of amino acid valine (V) to glutamic acid (E) at codon 600. Approximately 50% of melanomas harbor the V600E B-RAF mutation, while other mutations observed in melanomas are usually associated with the activation of N-RAS and c-KIT.

 

Several studies reported association of the V600E B-RAF mutation with the progression of melanoma. In a pre-clinical study Smalley et al. (2010) observed tumor formation in immunocompromised mice following introduction of mutant B-RAF in melanocytes. Inversely, in their study, Smalley et al. also observed that inhibition of mutated B-RAF using RNA-interference resulted in tumor cell death. In addition, several other studies reported that inhibition of V600E mutant B-RAF prevents melanoma cell proliferation, induces apoptosis (programmed cell death), and also blocks melanoma xenograft growth in vivo. Even though many studies suggested that V600E B-RAF mutation may not be sufficient alone for melanoma induction, a wealth of evidence demonstrated that mutated B-RAF is necessary for the maintenance and progression of melanoma in human. Therefore, mutated B-RAF represents a therapeutic target in melanoma, which is why several B-RAF kinase inhibitors have already been developed. Sorafenib was the first B-RAF inhibitor studied in melanoma patients. In addition, vemurafenib (Zelboraf) and dabrafenib (GSK2118436) were also studied in melanoma patients with V600E B-RAF mutations.  In 2011 vemurafenib received FDA approval for the treatment of melanoma patients harboring the V600E B-RAF mutation. In clinical trials, in which patients were undergoing treatment with vemurafenib, the drug reduced risk of death by 63% and risk of progression by 74%.

 

At present several clinical trials also evaluate clinical efficacy of vemurafenib in combination with leflunomide  (antirheumatic drug), GDC-0973 (MEK inhibitor), and metformin (antidiabetic drug). In addition, several other drugs targeting B-RAF and its downstream pathway are also in development. Therefore, further improvements can be expected in this personalized and targeted therapy in melan

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Earthquakes make gold veins -- pressure changes in Earth crust cause precious metals to deposit

Earthquakes make gold veins -- pressure changes in Earth crust cause precious metals to deposit | Amazing Science | Scoop.it

Scientists have long known that veins of gold are formed by mineral deposition from hot fluids flowing through cracks deep in Earth’s crust. But a study published today in Nature Geoscience has found that the process can occur almost instantaneously — possibly within a few tenths of a second.

 

The process takes place along 'fault jogs' — sideways zigzag cracks that connect the main fault lines in rock, says first author Dion Weatherley, a seismologist at the University of Queensland in Brisbane, Australia.

When an earthquake hits, the sides of the main fault lines slip along the direction of the fault, rubbing against each other. But the fault jogs simply open up. Weatherley and his co-author, geochemist Richard Henley at the Australian National University in Canberra, wondered what happens to fluids circulating through these fault jogs at the time of the earthquake.

 

What their calculations revealed was stunning: a rapid depressurization that sees the normal high-pressure conditions deep within Earth drop to pressures close to those we experience at the surface. For example, a magnitude-4 earthquake at a depth of 11 kilometres would cause the pressure in a suddenly opening fault jog to drop from 290 megapascals (MPa) to 0.2 MPa. (By comparison, air pressure at sea level is 0.1 MPa.) “So you’re looking at a 1,000-fold reduction in pressure,” Weatherley says.

 

Big earthquakes will produce bigger pressure drops, but for gold-vein formation, that seems to be overkill. More interesting, Weatherley and Henley found, is that even small earthquakes produce surprisingly big pressure drops along fault jogs. “We went all the way to magnitude –2,” Weatherley says — an earthquake so small, he adds, that it involves a slip of only about 130 micrometres along a mere 90 centimetres of the fault zone. “You still get a pressure drop of 50%,” he notes.


That, Weatherley adds, might be one of the reasons that the rocks in gold-bearing quartz deposits are often marbled with a spider web of tiny gold veins. “You [can] have thousands to hundreds of thousands of small earthquakes per year in a single fault system,” he says. “Over the course of hundreds of thousands of years, you have the potential to precipitate very large quantities of gold. Small bits add up.”

 

Weatherley says that prospectors might be able to use remote sensing techniques to find new gold deposits in deeply buried rocks in which fault jogs are common. “Fault systems with lots of jogs can be places where gold can be distributed,” he explains.

 

But Taka’aki Taira, a seismologist at the University of California, Berkeley, thinks that the finding might have even more scientific value. That’s because, in addition to showing how quartz deposits might form in fault jogs, the study reveals how fluid pressure in the jogs rebounds to its original level — something that could affect how much the ground moves after the initial earthquake.

more...
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Why makeup matters - Brain uses contrast of facial features to judge a person's age

Why makeup matters - Brain uses contrast of facial features to judge a person's age | Amazing Science | Scoop.it

The contrasting nature of facial features is one of the signals that people unconsciously use to decipher how old someone looks, says Psychology Prof. Richard Russell, who has been collaborating with researchers from CE.R.I.E.S. (Epidermal and Sensory Research and Investigation Center), a department of Chanel Research and Technology dedicated to skin related issues and facial appearance.

 

"Unlike with wrinkles, none of us are consciously aware that we're using this cue, even though it stares us in the face every day," said Russell. The discovery of this cue to facial age perception may partly explain why cosmetics are worn the way they are, and it lends more evidence to the idea that makeup use reflects our biological as well as our cultural heritage, according to Russell. In one study, Russell and his team measured images of 289 faces ranging in age from 20 to 70 years old, and found that through the aging process, the color of the lips, eyes and eyebrows change, while the skin becomes darker. This results in less contrast between the features and the surrounding skin – leaving older faces to have less contrast than younger faces.

 

The difference in redness between the lips and the surrounding skin decreases, as does the luminance difference between the eyebrow and the forehead, as the face ages. Although not consciously aware of this sign of aging, the mind uses it as a cue for perceiving how old someone is.


In another study involving more than a hundred subjects in Gettysburg and Paris, the scientists artificially increased these facial contrasts and found that the faces were perceived as younger. When they artificially decreased the facial contrasts, the faces were perceived as older.


The image shows two identical images of the same face, except that the facial contrast has been increased in the left image and decreased in the right image. The face on the left appears younger than the one on the right.


Cosmetics are commonly used to increase aspects of facial contrast, such as the redness of lips. Scientists propose that this can partly explain why makeup is worn the way that it is – shades of lipstick that increase the redness of the lips are making the face appear younger, which is related to healthiness and beauty.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

The RX J0648.0-4418 white dwarf star "Dizzy" is the densest and fastest spinning dwarf star known

The RX J0648.0-4418 white dwarf star "Dizzy" is the densest and fastest spinning dwarf star known | Amazing Science | Scoop.it

Dizzy the white dwarf star is under a powerful curse, doomed to spin faster than any of its peers. No one knows why poor Dizzy was handed such a fate, but its wild gyrations mean that the star could be headed for a violent death, perhaps unlike any stellar explosion we've seen before.

 

White dwarfs are the dense cores left over when stars like the sun die. Dizzy, officially catalogued as RX J0648.0-4418, is probably the densest known white dwarf, packing more than the mass of our sun into a ball about the size of Mars.

 

The star takes only 13.2 seconds to spin once on its axis. The next fastest white dwarf, AE Aquarii, takes 33 seconds per revolution. If Earth were somehow set spinning as fast as Dizzy, people would rapidly be flung out into space, followed closely by the oceans, mountains and crust. The deep rocky mantle and almost all of Earth's core would also be torn apart by this super-spin.

 

"Even if this were a normal white dwarf of half a solar mass, it would be close to or beyond the limit of break-up," says Sandro Mereghetti of the Institute of Astrophysics and Cosmic Physics in Milan, Italy. Luckily for Dizzy, being extra-dense means that its surface gravity is well over a million times as strong as Earth's, so it can hold itself together.

 

It is possible Dizzy was born this way, the core of a fast-spinning ordinary star that spun even faster as it contracted. But Mereghetti suspects otherwise.

 

He thinks Dizzy got a push from its orbital partner, a hot star called HD 49798. A few hundred thousand years ago, an ageing HD 49798 began to expand into a red giant, but then its outer layers were siphoned off by the white dwarf, he argues. Spiralling down to hit Dizzy at an oblique angle, that material would have made the dwarf spin super-fast.

 

One day HD 49798 will again swell in size as it runs out of nuclear fuel. Then Dizzy will take up even more material. A few million years on, it will reach a critical mass that should signal its demise. What happens next depends on chemistry.

 

If Dizzy has an oxygen-carbon mix, like most white dwarfs, an explosive thermonuclear reaction could rip through its body, generating a type Ia supernova. Because of Dizzy's spin, the critical mass for this could be higher than normal, so the resulting supernova would be ultra-bright. Dizzy is close enough to us that we might see it shining as bright as the full moon.

 

But Dizzy might be a blend of oxygen and neon. In that case, the dwarf could collapse and leave behind what is called a millisecond pulsar – a rapidly spinning neutron star. This type of stellar explosion has never been seen before, although it would be a much less spectacular event.

more...
No comment yet.