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Carbon Nanotubes Could Solve Overheating Problem for Next-Generation Computer Chips

Carbon Nanotubes Could Solve Overheating Problem for Next-Generation Computer Chips | Amazing Science | Scoop.it

Computer chips used in next-generation smartphones and supercomputers can't get much faster without overheating. That's why engineers hope carbon nanotubes offer a possible cooling solution that could enable processing speeds to continue accelerating.


The overheating problem has become steadily worse as engineers cram more power-hungry transistors into the same microchip space, because much of the electricity that powers the transistors is wasted as heat. Carbon nanotubes have high thermal conductivity that could carry the excess heat away from the microchips, but only if engineers can figure out how to improve the heat transfer at the point of contact between the nanotubes and microchips.


"The thermal conductivity of carbon nanotubes exceeds that of diamond or any other natural material but because carbon nanotubes are so chemically stable, their chemical interactions with most other materials are relatively weak, which makes for  high thermal interface resistance," said Frank Ogletree, a physicist with the Lawrence Berkeley National Laboratory’s Materials Sciences Division, in a news release.


Ogletree and his colleagues worked with two former Intel researchers to figure out how to make a six-fold improvement in the heat flow between metal and carbon nanotubes. Their work is detailed in the 22 January issue of the journal Nature Communications.


The new study's success rests upon using organic molecules as a bridge between the carbon nanotubes and metal—a method that greatly reduces the interface resistance that would otherwise prevent heat from flowing more efficiently between the materials. The organic molecules, including aminopropyl-trialkoxy-silane (APS) and cysteamine, create strong covalent bonds between the carbon nanotubes and the metal used in microchips. The same bonding technique pioneered by the researchers can also work with graphene—a promising material for complementing silicon transistors.


"With carbon nanotubes, thermal interface resistance adds something like 40 [micrometers] of distance on each side of the actual carbon nanotube layer," said Sumanjeet Kaur, lead author of the Nature Communications paper and an industrial postdoctoral scientist at Porifera. "With our technique, we’re able to decrease the interface resistance so that the extra distance is around seven microns at each interface."


This success will help pave the way for carbon nanotubes' use in this application. But there is still a ways to go before we see them in commercially-available gadgets. One problem is that most nanotubes, grown in vertically-aligned arrays on silicon wafers, don't make contact with the metal surfaces. But the Berkeley team hopes to improve

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Researchers discover the gene (PIEZO2) behind proprioception

Researchers discover the gene (PIEZO2) behind proprioception | Amazing Science | Scoop.it

A soft brush that feels like prickly thorns. A vibrating tuning fork that produces no vibration. Not being able to tell which direction body joints are moving without looking at them. Those are some of the bizarre sensations reported by a 9-year-old girl and 19-year-old woman in a new study. The duo, researchers say, shares an extremely rare genetic mutation that may shed light on a so-called “sixth sense” in humans: proprioception, or the body’s awareness of where it is in space. The new work may even explain why some of us are klutzier than others.

 

The patients’ affliction doesn’t have a name. It was discovered by one of the study’s lead authors, pediatric neurologist Carsten Bönnemann at the National Institutes of Health (NIH) in Bethesda, Maryland, who specializes in diagnosing unknown genetic illnesses in young people. He noticed that the girl and the woman shared a suite of physical symptoms, including hips, fingers, and feet that bent at unusual angles. They also had scoliosis, an unusual curvature of the spine. And, significantly, they had difficulty walking, showed an extreme lack of coordination, and couldn’t physically feel objects against their skin.

 

Bönnemann screened their genomes and looked for mutations that they might have in common. One in particular stood out: a catastrophic mutation in PIEZO2, a gene that has been linked to the body’s sense of touch and its ability to perform coordinated movements. At about the same time, in a “very lucky accident,” Bönnemann attended a lecture by Alexander Chesler, a neurologist also at NIH, on PIEZO2. Bönnemann invited Chesler to help study his newly identified patients.

 

It wasn’t the disease’s rarity that so shocked Chesler when he met the girl and young woman; it was the fact that when scientists had previously knocked out PIEZO2 in mouse models, it had always proven fatal. Most assumed people couldn’t live without it, either.

 

The researchers performed a battery of tests with the patients and a control group. When blindfolded, the patients staggered, stumbled, and fell. But with the blindfold removed, they could walk almost normally. The patients also performed a task where they moved their index finger from their nose to a target placed in front of them. Blindfolded, they failed miserably. Eyes uncovered, they did well. The researchers held the patients’ arms and moved the joints either up or down, asking them to indicate the direction. Blindfolded, they couldn’t tell which direction their joints were being moved. No blindfold, and—naturally—they could tell just by looking.

 

Together, the tests suggested the patients totally lacked proprioception, the researchers report online today in The New England Journal of Medicine.

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Hubble finds planet orbiting pair of stars

Hubble finds planet orbiting pair of stars | Amazing Science | Scoop.it

Astronomers using NASA's Hubble Space Telescope, and a trick of nature, have confirmed the existence of a planet orbiting two stars in the system OGLE-2007-BLG-349, located 8,000 light-years away towards the center of our galaxy.

 

The planet orbits roughly 300 million miles from the stellar duo, about the distance from the asteroid belt to our sun. It completes an orbit around both stars roughly every seven years. The two red dwarf stars are a mere 7 million miles apart, or 14 times the diameter of the moon's orbit around Earth.

 

The Hubble observations represent the first time such a three-body system has been confirmed using the gravitational microlensing technique. Gravitational microlensing occurs when the gravity of a foreground star bends and amplifies the light of a background star that momentarily aligns with it. The particular character of the light magnification can reveal clues to the nature of the foreground star and any associated planets.

 

The three objects were discovered in 2007 by an international collaboration of five different groups: Microlensing Observations in Astrophysics (MOA), the Optical Gravitational Lensing Experiment (OGLE), the Microlensing Follow-up Network (MicroFUN), the Probing Lensing Anomalies Network (PLANET), and the Robonet Collaboration. These ground-based observations uncovered a star and a planet, but a detailed analysis also revealed a third body that astronomers could not definitively identify.

 

"The ground-based observations suggested two possible scenarios for the three-body system: a Saturn-mass planet orbiting a close binary star pair or a Saturn-mass and an Earth-mass planet orbiting a single star," explained David Bennett of the NASA Goddard Space Flight Center in Greenbelt, Maryland, the paper's first author.

 

The sharpness of the Hubble images allowed the research team to separate the background source star and the lensing star from their neighbors in the very crowded star field. The Hubble observations revealed that the starlight from the foreground lens system was too faint to be a single star, but it had the brightness expected for two closely orbiting red dwarf stars, which are fainter and less massive than our sun. "So, the model with two stars and one planet is the only one consistent with the Hubble data," Bennett said.


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Human Neuron Transplants Treat Spinal Cord Injury in Mice

Human Neuron Transplants Treat Spinal Cord Injury in Mice | Amazing Science | Scoop.it

Chronic pain and loss of bladder control are among the most devastating consequences of spinal cord injury, rated by many patients as a higher priority for treatment than paralysis or numbness. Now a UC San Francisco team has transplanted immature human neurons into mice with spinal cord injuries, and shown that the cells successfully wire up with the damaged spinal cord to improve bladder control and reduce pain. This is a key step towards developing cell therapies for spinal cord injury in humans, say the researchers, who are currently working to develop the technique for future clinical trials.

 

Recent mouse studies have demonstrated that transplants of neurons may be effective treatments for neuropathic pain, epilepsy, and even Parkinson’s disease. The new study – published Sept. 22, 2016, in Cell Stem Cell – is the first to successfully transplant human neurons as a treatment for symptoms of spinal cord injury.

 

“This is an important proof of principle for using cell therapy to repair damaged neural tissue. It brings us one step closer to using such transplants to bring much needed relief to people with spinal cord injuries,” said co-senior author Arnold Kriegstein, MD, PhD, who is a professor of developmental and stem cell biology and director of the Broad Center of Regeneration Medicine and Stem Cell Research at UCSF.


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Designer Agent Blocks Pain Without Morphine’s Side Effects

Designer Agent Blocks Pain Without Morphine’s Side Effects | Amazing Science | Scoop.it

Scientists have synthesized a molecule with a unique profile of highly specific pain-relieving properties and demonstrated its efficacy in mice. Compared to existing opioid pain relievers, like morphine, the new agent, called PZM21, was not “reinforcing” or prone to triggering potentially lethal respiratory impairment – and was also less constipating.

 

Also unlike existing analgesics, it had little effect on spinal cord reflexive responses, instead targeting the brain-mediated emotional/experiential component of pain. In addition to clinical potential, PZM21 also holds promise as a “tool molecule” for exploring the workings of brain pain systems, say the researchers.

 

The study represents the combined efforts of NIH-funded research teams led by Nobel laureate Brian Kobilka, M.D. , of Stanford University, NIMH-funded Bryan Roth, M.D., Ph.D. (inventor of the chemogenetic technology DREADD), of the University of North Carolina, and Brian Shoichet, Ph.D., of the University of California San Francisco. They report on their findings August 17, 2016 in the journal Nature.


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Combining wide-field micro-elastography with Optical Coherence Tomography (OCT)

Combining wide-field micro-elastography with Optical Coherence Tomography (OCT) | Amazing Science | Scoop.it

Incomplete excision of malignant tissue is a major issue in breast-conserving surgery, with typically 20 - 30% of cases requiring a second surgical procedure arising from postoperative detection of an involved margin. A team of scientists and engineers now report advances in the development of a new intraoperative tool, optical coherence micro-elastography, for the assessment of tumor margins on the micro-scale. They demonstrate an important step by conducting whole specimen imaging in intraoperative time frames with a wide-field scanning system acquiring mosaicked elastograms with overall dimensions of ~50 × 50 mm, large enough to image an entire face of most lumpectomy specimens. This capability is enabled by a wide-aperture annular actuator with an internal diameter of 65 mm. The team demonstrates feasibility by presenting elastograms recorded from freshly excised human breast tissue, including from a mastectomy, lumpectomies and a cavity shaving.

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Towards Stable Propagation of Light in Nano-Photonic Fibers

Towards Stable Propagation of Light in Nano-Photonic Fibers | Amazing Science | Scoop.it

Devices based on light, rather than electrons, could revolutionize the speed and security of our future computers. However, one of the major challenges in today's physics is the design of photonic devices, able to transport and switch light through circuits in a stable way.

 

Sergej Flach, Director of the Center for Theoretical Physics of Complex Systems, within the Institute for Basic Science (IBS) and colleagues from the National Technical University of Athensand the University of Patras (Greece) have studied how to achieve a more stable propagation of light for future optical technologies. Their model was recently published in Scientific Reports.

 

Optical fibers can carry a large amount of information and are already used in many countries for communications via phone, internet and TV. However, when light travels long distances through these fibers, it suffers from losses and leakages, which could lead to a loss of information. In order to compensate for this problem, amplifiers are positioned at specific intervals to amplify the signal. For example, amplifiers are needed in submarine communications cables that allow the transfer of digital data between all continents (except for Antarctica).

 

Researchers have tried to build fibers where the signal is stable along the pathway and does not need amplifiers, using the so-called "PT symmetry". P stands for parity reversal and T for time reversal. The PT symmetry can be simplified with an example.

 

Imagine a situation where two cars are traveling at the same speed at some instant in time. However, one car is speeding up and the other one is slowing down. Using parity reversal (P) we exchange one car for the other. Using time reversal (T) we go back in time. If you are in the car that is accelerating, you can jump to the car that is slowing down (P) and you also go back in time (T). As a result, you will end up with the same speed as the accelerating car. The cars are like light waves inside the optical fibers and the speed is a representation of the intensity of light. The jumping symbolizes of the transfer of light from one fiber to another, which happens when the light waves propagating in each fiber overlap partially with each other, through a phenomenon called tunneling.

 

The PT symmetry idea is that one can carefully balance the intensity of light inside the fibers and achieve a stable propagation. Researchers expected PT symmetry to be the solution to achieve stable propagation in all-optical devices (diodes, transistors, switches etc.). However, stable propagation is still a challenge because the PT symmetry conditions have to be balanced extremely carefully, and because the material of the fibers reacts and destroys the exact balance. In the example of the cars, in order to achieve perfect PT symmetry, you would need really identical cars and street conditions. Reality is of course much different.

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Dogs process vocabulary and intonation in their brains, similar to how humans do it

Dogs process vocabulary and intonation in their brains, similar to how humans do it | Amazing Science | Scoop.it
How do dogs pick up on our tones, gestures, and moods?

 

Ever gotten the feeling that your dog is listening not just to what you say, but how you say it? You’re not alone among pet owners — and a new study in Science suggests that you’re not wrong, either.

 

Using fMRI machines, researchers measured the brain activity of dogs as they were given commands. Attila Andics, a neuroscientist at Eötvös Loránd University in Budapest and one of the paper’s authors, says the team found that dogs process vocabulary and intonation in different parts of their brains, similar to the way humans do.

 

“We said ‘Good boy! Good boy!’ [to the dogs],” Andics says. “But we also said ‘Good boy, good boy’ without the praising intonation. And … we used meaningless conjuncture words like ‘however’ or nevertheless’ in a praising intonation — and also some of these meaningless words in a normal intonation. And so we basically we could test for the differences in the brain.”

 

When the dogs heard praising words in praising intonations, the reward centers of their brain were active, indicating pleasure. This wasn’t the case when praise words were spoken neutrally, Andics says, or when meaningless words were spoken in a praising voice. The findings indicate that dogs can take communication cues straight from our speech.

 

“It’s as if you are calling your dog on the phone,” Andics says. “[In the study,] they only have the speech information, and they don’t see you or they don’t see your body gestures. They don’t have all the context. This is only word meaning and intonation which is at play here. So we were really surprised to see that they can, in this setting, actually use both of these types of cues.”

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Good news: acidity in atmosphere minimized to preindustrial levels

Good news: acidity in atmosphere minimized to preindustrial levels | Amazing Science | Scoop.it

New research shows that human pollution of the atmosphere with acid is now almost back to the level that it was before the pollution started with industrialization in the 1930s. The results come from studies of the Greenland ice sheet.

 

The Greenland ice sheet is a unique archive of the climate and atmospheric composition far back in time. The ice sheet is made up of snow that falls and never melts, but rather remains year after year and is gradually compressed into ice. By drilling ice cores down through the kilometer-thick ice sheet, the researchers can analyze every single annual layer, which can tell us about past climate change and concentration of greenhouse gases and pollutants in the atmosphere.

 

Acid in the atmosphere can come from large volcanic eruptions and manmade emissions from industry. You can measure acidity in the ice by simply passing an instrument that can measure conductivity over the ice core. If there is a high level of acidity, the measurement turns out and it works great for measuring the climate of the past all the way back to the last interglacial period 125,000 years ago. But if you want to measure atmospheric acidity for the last 100 years, it is more difficult as the annual layers are located in the uppermost 60 meters and there the ice is more porous as it has not yet been compressed into hard ice.

 

For many years, there has been a quest to solve the problem of measuring acidity in the porous annual layers of the ice and now scientists from the Niels Bohr Institute have succeeded. The method is a Continuous Flow Analyses or CFA method and it was originally invented in Switzerland, but Helle Astrid Kjær has spearheaded the further development of the system so it can also measure acid.

 

 

In addition to being able to measure the pH value more accurately using the new method, the CFA system can also distinguish whether the emissions come from volcanic eruptions, large forest fires or industry. The researchers can therefore filter out both volcanic eruptions and forest fires in the assessment of industrial pollution and the new results are revolutionary. 

 

“We can see that the acid pollution in the atmosphere from industry has fallen dramatically since manmade acid pollution took off in the 1930s and peaked in the 1960s and 70s. In the 1970s, both Europe and the United States adopted the ‘The clean air act amendments’, which required filters in factories, thus reducing acid emissions and this is what we can now see the results of. The pollution of acid in the atmosphere is now almost down to the level it was before the pollution really took off in the 1930s, explains Helle Astrid Kjær.

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When Blind People Do Algebra, The Brain's Visual Areas Light Up

When Blind People Do Algebra, The Brain's Visual Areas Light Up | Amazing Science | Scoop.it

People born without sight appear to solve math problems using visual areas of the brain. A functional MRI study of 17 people blind since birth found that areas of visual cortex became active when the participants were asked to solve algebra problems, a team from Johns Hopkins reports in the Proceedings of the National Academy of Sciences.

 

"And as the equations get harder and harder, activity in these areas goes up in a blind person," says Marina Bedny, an author of the study and an assistant professor in the department of psychological and brain sciences at Johns Hopkins University.

 

In 19 sighted people doing the same problems, visual areas of the brain showed no increase in activity. "That really suggests that yes, blind individuals appear to be doing math with their visual cortex," Bedny says.

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Quantum Teleportation Enters the Real World

Quantum Teleportation Enters the Real World | Amazing Science | Scoop.it
It may not be the teleportation you saw in Star Trek, but researchers have sent information across a city via quantum entanglement.

 

Two separate teams of scientists have taken quantum teleportation from the lab into the real world.

Researchers working in Calgary, Canada and Hefei, China, used existing fiber optics networks to transmit small units of information across cities viaquantum entanglement — Einstein’s “spooky action at a distance.”

 

According to quantum mechanics, some objects, like photons or electrons, can be entangled. This means that no matter how far apart they are, what happens to one will affect the other instantaneously. To Einstein, this seemed ridiculous, because it entailed information moving faster than the speed of light, something he deemed impossible. But, numerous experiments have shown that entanglement does indeed exist. The challenge was putting it to use.

 

A few experiments in the lab had previously managed to send information using quantum entanglement. But translating their efforts to the real world, where any number of factors could confound the process is a much more difficult challenge. That’s exactly what these two teams of researchers have done. Their breakthrough, published in two separate papers today in Nature Photonics, promises to offer important advancements for communications and encryption technologies.

 

Both experiments encode a message into a photon and send it to a way station of sorts. There, the message is transferred to a different photon, which is entangled with a photon held by the receiver. This destroys the information held in the first photon, but transmits the information via entanglement to the receiver. When the way station measures the photon, it creates kind of key — a decoder ring of sorts — that can decrypt the entangled photon’s information. That key is then sent over an internet connection, where it is combined with the information contained within the entangled photon to reveal the message.

 

The two experiments weren’t able to transmit very much information — the Calgary experiment was the quickest, and they only managed 17 photons a minute. The Hefei experiment was able to guess the state of the photons with better accuracy, however. While the Calgary researchers succeeded about 25 percent of the time, the Hefei researchers were right at most 50 percent of the time, due to their inclusion of an extra, albeit time-consuming, step in the process. Because both methods possess their own advantages, they will likely each form the basis for further research.

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Jeff Domansky's curator insight, September 20, 12:50 PM

Something to talk about on your next coffee break. Star Trek may not be far off after all.

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Pigeons On Par with Monkeys to Visually Recognize Words

Pigeons On Par with Monkeys to Visually Recognize Words | Amazing Science | Scoop.it

Dr. Damian Scarf of the University of Otago’s Department of Psychology, the study’s first author, and his colleagues from Germany and New Zealand found that pigeons’ performance was on a par with that previously reported in baboons for this type of complex task. Their study, published in the Proceedings of the National Academy of Sciences, is the first to identify a non-primate species as having ‘orthographic’ abilities.

 

In the experiment, pigeons were trained to peck four-letter English words as they came up on a screen, or to instead peck a symbol when a four-letter non-word, such as ‘URSP’ was displayed. The scientists added words one by one with the four pigeons in the study eventually building vocabularies ranging from 26 to 58 words and over 8,000 non-words.

 

To check whether the pigeons were learning to distinguish words from non-words rather than merely memorizing them, they introduced words the birds had never seen before. The pigeons correctly identified the new words as words at a rate significantly above chance.

 

According to Dr. Scarf, they performed this feat by tracking the statistical likelihood that ‘bigrams,’ letter pairs such as ‘EN’ and ‘AL’, were more likely associated with words or non-words.

 

Co-author Prof. Onur Güntürkün, from the Department of Biopsychology at the Ruhr-University Bochum, Germany, said “that pigeons — separated by 300 million years of evolution from humans and having vastly different brain architectures — show such a skill as orthographic processing is astonishing.”

 

“We may have to seriously re-think the use of the term ‘bird brain’ as a put down,” added study senior author Prof. Michael Colombo, from the University of Otago’s Department of Psychology.

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Moon’s pull can trigger big earthquakes

Moon’s pull can trigger big earthquakes | Amazing Science | Scoop.it
Geologic strain of tides during full and new moons could increase magnitude of tremors.

 

Big earthquakes, such as the ones that devastated Chile in 2010 and Japan in 2011, are more likely to occur during full and new moons — the two times each month when tidal stresses are highest.

 

Earth’s tides, which are caused by a gravitational tug-of-war involving the Moon and the Sun, put extra strain on geological faults. Seismologists have tried for decades to understand whether that stress could trigger quakes. They generally agree that the ocean’s twice-daily high tides can affect tiny, slow-motion tremors in certain places, including California’s San Andreas fault1 and the Cascadia region2 of the North American west coast.

 

But a new study, published on 12 September in Nature Geoscience3, looks at much larger patterns involving the twice-monthly tides that occur during full and new moons. It finds that the fraction of high magnitude earthquakes goes up globally as tidal stresses rise.

 

Satoshi Ide, a seismologist at the University of Tokyo, and his colleagues investigated three separate earthquake records covering Japan, California and the entire globe. For the 15 days leading up to each quake, the scientists assigned a number representing the relative tidal stress on that day, with 15 representing the highest. They found that large quakes such as those that hit Chile and Tohoku-Oki occurred near the time of maximum tidal strain — or during new and full moons when the Sun, Moon and Earth align.

 

For more than 10,000 earthquakes of around magnitude 5.5, the researchers found, an earthquake that began during a time of high tidal stress was more likely to grow to magnitude 8 or above.

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Plasmon-enhanced thermophoresis for the reversible assembly of plasmonic nanoparticles

Plasmon-enhanced thermophoresis for the reversible assembly of plasmonic nanoparticles | Amazing Science | Scoop.it

The optical manipulation of plasmonic nanoparticles – metal nanoparticles that are highly efficient at absorbing and scattering light – has advantages for applications such as nanofabrication, drug delivery and biosensing. To that end, researchers have been developing techniques for the reversible assembly of plasmonic nanoparticles that can be used to modulate their structural, electrical and optical properties.The latest such technique is a low-power assembly that is enabled by thermophoretic migration of nanoparticles due to the plasmon-enhanced photothermal effect and the associated enhanced local electric field over a plasmonic substrate.

 

An international research team, led by Yuebing Zheng, Assistant Professor of Mechanical Engineering and Materials Science & Engineering at the University of Texas at Austin, has developed a new optical assembly technique known as plasmon-enhanced thermophoresis to assemble plasmonic nanoparticles reversibly by optically controlling a temperature field.This plasmon-enhanced thermophoresis can be exploited to confine plasmonic nanoparticles in a higher-temperature regime under a thermoelectric field.The researchers reported their findings in the September 17, 2016 online edition of ACS Nano ("Light-Directed Reversible Assembly of Plasmonic Nanoparticles Using Plasmon-Enhanced Thermophoresis").


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GUIDE-seq: A DNA Duct Tape to mark the DNA Damage

GUIDE-seq: A DNA Duct Tape to mark the DNA Damage | Amazing Science | Scoop.it

GUIDE-Seq deals with DNA double-strand breaks (DSB) and stands for genome-wide unbiased identification of DSBs evaluated by sequencing. Basically, the technology seeks out damage hotspots where duct tape-like DNA fragments can seal the damaged DNA and leave an identifiable mark there. Oftentimes, these repairs are like duct tape fixes at home—they're not always perfect. GUIDE-Seq can efficiently track down taped locations, which can help trace DNA damage and repair processes.

 

The duct tape is effective in animal cells. But plant cells—with their tough cell walls—have difficulty getting the tape into the cells to mark DNA breaks. In a spotlight article published in Trends in Plant Science (DOI: 10.1016/j.tplants.2016.08.005), biologists from Michigan Technological University elaborate how GUIDE-Seq could be a solution for observing plant DNA damage, repair and evolution.

 

Damaged DNA will sometimes create a mismatched sequence when repaired, much like pushing a shirt button through the wrong hole. Such a small mistake creates an uneven sequence that makes a big difference in genetic blueprints. "Without DNA repairing, we wouldn't be able to survive," says Guiliang Tang, a professor of biological sciences at Michigan Tech and the paper's corresponding author. He explains that cells naturally repair DNA and now, with the new technology CRISPR-Cas9, genes can be modified by people, which also requires DNA repair.

 

"Nature introduces random DNA damage, which can be anywhere within the genome," Tang explains. "While CRISPR can introduce very specific DNA damages for modifications through repairing."

 


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Ancient DNA traces extinct Caribbean ‘Island Murderer’ back to the dawn of mammals

Ancient DNA traces extinct Caribbean ‘Island Murderer’ back to the dawn of mammals | Amazing Science | Scoop.it

From skeletal remains found among ancient owl pellets, a team of scientists has recovered the first ancient DNA of the extinct West Indian mammal Nesophontes, meaning “island murder.” They traced its evolutionary history back to the dawn of mammals 70 million years ago.

 

The insect-eating creature existed in the Caribbean islands until the 16th century when, perhaps, they were outcompeted as the first Spanish ships arrived—introducing rats as stowaways.

 

Nesophontes was just one of the dozens of mammals that went extinct in the Caribbean during recent times,” said Professor Ian Barnes, Research Leader at London’s Natural History Museum.

 

Scientists used a 750-year-old specimen to generate many thousands of base pairs of DNA sequence data. This allowed the research team to uncover its evolutionary origins and finally resolve the relationships between its closest relatives, the insectivores, a group including shrews, hedgehogs and moles.

 

Phylogenetic and divergence time scenarios clearly demonstrate that Nesophontes is a deeply distinct sister group to another group of living native Caribbean insectivores, the solenodons. The time of the split between these two correlates with an era when the northern Caribbean was formed of volcanic islands, well before the origins of the islands we see today.

Obtaining DNA from tropical fossils is notoriously difficult, and the team made use of the latest developments in ancient DNA technology to conduct the study.

 

“Once we’d dealt with the tiny size of the bone samples, the highly degraded state of the DNA, and the lack of any similar genomes to compare to, the analysis was a piece of cake,” said Natural History Museum scientist Dr. Selina Brace.

 

The findings will be of considerable interest for evolutionary biologists studying mammalian biogeography, and the significant role that humans may have played in a recent extinction.

 

 

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Extreme bacteria can photosynthesise in near total darkness

Extreme bacteria can photosynthesise in near total darkness | Amazing Science | Scoop.it

In the mud layers at the bottom of lakes and the sea live bacteria that are so extreme that they can convert sunlight into usable energy. They do it with the help of special antennae and a team of scientists have now mapped the structure of a part of these antennae.

 

The discovery is the holy grail of molecular photosynthesis research and could eventually be used to make more effective solar cells that are capable of producing electricity at night. “It’s certainly far off in future, but we can definitely learn something from nature,” says co-author Jakob Toudahl Nielsen, from the Centre for Insoluble Protein Structures (inSPIN) at Aarhus University, Denmark.

 

“We might be able to make green solar cells than can cope at low levels of light and the knowledge gained from these bacteria could lead the way,” says Nielsen.

 

The study was recently published in the scientific journal Nature Communications.


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Uncovering a Quantum Phase Transition in Nuclei

Uncovering a Quantum Phase Transition in Nuclei | Amazing Science | Scoop.it
Simulations predict that the ground states of certain light nuclei lie near a quantum phase transition between a liquid-like phase and a phase involving clusters of alpha particles.

 

Thermal phase transitions surround us. Ice melts. Water boils. Triggered by thermal fluctuations, these transitions are typically characterized by a reorganization of matter at a critical temperature from one distinct phase to another. Less obvious in our everyday lives are phase transitions that occur in quantum systems at zero temperature. These quantum phase transitions exist in many condensed matter systems, in which tuning such variables as pressure, atom concentration, or magnetic field brings one quantum phase to a “critical point” with another.

 

Instead of thermal fluctuations, these transitions are driven by the quantum fluctuations dictated by the uncertainty principle, and they often involve competing interactions (for example, repulsive versus attractive) between the phases.

 

Now, theorists simulating the interactions between protons and neutrons in a nucleus have found that certain light nuclei exist near a quantum phase transition. The transition is from a state with a uniform distribution of protons and neutrons (a Fermi liquid) to a state consisting of several alpha particles (two protons and two neutrons) [1]. The finding, from Dean Lee at North Carolina State University, Raleigh, and colleagues, might provide clues as to why clustering occurs in the ground states of some nuclei but only in the excited states of others—such as the excited Hoyle state of carbon that is thought to be essential to life.

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New anti-cancer gene therapy technique targets microRNAs for the first time

New anti-cancer gene therapy technique targets microRNAs for the first time | Amazing Science | Scoop.it

A new gene therapy technique being developed by researchers at MIT is showing promise as a way to prevent breast cancer tumors from metastasizing. The treatment, described in a paper published today in the journal Nature Communications, uses microRNAs — small noncoding RNA molecules that regulate gene expression — to control metastasis.

 

The therapy could be used alongside chemotherapy to treat early-stage breast cancer tumors before they spread, according to Natalie Artzi, a principal research scientist at MIT’s Institute for Medical Engineering and Science (IMES) and an assistant professor of medicine at Brigham and Women’s Hospital, who led the research in collaboration with Noam Shomron, an assistant professor on the faculty of medicine at Tel-Aviv University in Israel.

 

“The basic idea is that if the cancer is diagnosed early enough, then in addition to treating the primary tumor with chemotherapy, one could also treat with specific microRNAs, in order to prevent the spread of cancer cells that cause metastasis,” Artzi says. The regulation of gene expression by microRNAs is known to be important in preventing the spread of cancer cells. Recent studies by the Shomron team in Tel-Aviv have shown that disruption of this regulation, for example by genetic variants known as single nucleotide polymorphisms (SNPs), can have a significant impact on gene expression levels and lead to an increase in the risk of cancer.

 

To identify the specific microRNAs that play a role in breast cancer progression and could therefore potentially be used to suppress metastasis, the research teams first carried out an extensive bioinformatics analysis. They compared three datasets: one for known SNPs; a second for sites at which microRNAs bind to the genome; and a third for breast cancer-related genes known to be associated with the movement of cells.

 

This analysis revealed a variant, or SNP, known as rs1071738, which influences metastasis. They found that this SNP disrupts binding of two microRNAs, miR-96 and miR-182. This disruption in turn prevents the two microRNAs from controlling the expression of a protein called Palladin. Previous research has shown that Palladin plays a key role in the migration of breast cancer cells, and their subsequent invasion of otherwise healthy organs.

 

When the researchers carried out in vitro experiments in cells, they found that applying miR-96 and miR-182 decreased the expression of Palladin levels, in turn reducing the ability of breast cancer cells to migrate and invade other tissue.
“Previous research had discussed the role of Palladin in controlling migration and invasion (of cancer cells), but no one had tried to use microRNAs to silence those specific targets and prevent metastasis,” Artzi says. “In this way we were able to pinpoint the critical role of these microRNAs in stopping the spread of breast cancer.”

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Allen Institute publishes highest resolution map of the entire human brain to date

Allen Institute publishes highest resolution map of the entire human brain to date | Amazing Science | Scoop.it

The Allen Institute for Brain Science has published the highest resolution atlas of the human brain to date in a stand-alone issue of the Journal of Comparative Neurology. This digital human brain atlas allows researchers to investigate the structural basis of human brain function.

 

“To understand the human brain, we need to have a detailed description of its underlying structure,” says Ed Lein, Ph.D., Investigator at the Allen Institute for Brain Science. “Human brain atlases have long lagged behind atlases of the brain of worms, flies or mice, both in terms of spatial resolution and in terms of completeness due to technical limitations related to the enormous size and complexity of the human brain. This large-scale focused effort aimed to create a large resource combining different data types at high resolution, and use these data to generate a comprehensive mapping of brain regions.” 

 

Combining neuroimaging with cellular resolution histological analysis and expert structural mapping, “This is the most structurally complete atlas to date and we hope it will serve as a new reference standard for the human brain across different disciplines,” says Lein.

 

To create this modern atlas, the team at the Allen Institute partnered with Bruce Fischl, Ph.D. at Massachusetts General Hospital to perform magnetic resonance and diffusion tensor imaging on an intact brain before it was cut into slabs and serially sectioned to allow histological staining of individual sections. This imaging on the same brain created opportunities for linking fine molecular and cellular studies of the brain in health and disease with non-invasive neuroimaging studies. 

 

The Allen Human Brain Reference Atlas aimed to advance human brain mapping by digitizing the histological data at true cellular microscopic resolution, creating a complete ontology of brain regions, and delineating all brain regions on a series of cross-sections through the brain. To image these sections, the Allen Institute team had to develop a new tile-based scanner that could image tissue sections the size of a complete human brain hemisphere at the resolution of roughly a hundredth of the width of a human hair. The atlas was drawn from a single postmortem brain obtained from a 34-year old female donor.

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Zircon dating: uncovering Earths oldest continental crust rocks, 4.02 Billion years old

Zircon dating: uncovering Earths oldest continental crust rocks, 4.02 Billion years old | Amazing Science | Scoop.it

Addressing fundamental unknowns about the earliest history of Earth’s crust, scientists have precisely dated the world’s oldest rock unit at 4.02 billion years old. Driven by the University of Alberta, the findings suggest that early Earth was largely covered with an oceanic crust-like surface.

 

“It gives us important information about how the early continents formed,” says lead author Jesse Reimink. “Because it’s so far back in time, we have to grasp at every piece of evidence we can. We have very few data points with which to evaluate what was happening on Earth at this time.” In fact, only three locations worldwide exist with rocks or minerals older than 4 billion years old: one from Northern Quebec, mineral grains from Western Australia, and the rock formation from Canada’s Northwest Territories examined in this new study.

 

While it is well known that the oldest rocks formed prior to 4 billion years ago, the unique twist on Reimink’s rock is the presence of well-preserved grains of the mineral zircon, leaving no doubt about the date it formed. The sample in question was found during fieldwork by Reimink’s PhD supervisor, Tom Chacko, professor in the Department of Earth and Atmosphere Sciences, in an area roughly 300 kilometres north of Yellowknife. Reimink recently completed his PhD at the University of Alberta before starting a post-doctoral fellowship at the Carnegie Institute for Science in Washington, D.C.

 

“Zircons lock in not only the age but also other geochemical information that we’ve exploited in this paper,” Reimink continues. “Rocks and zircon together give us much more information than either on their own. Zircon retains its chemical signature and records age information that doesn’t get reset by later geological events, while the rock itself records chemical information that the zircon grains don’t.”

 

He explains that the chemistry of the rock itself looks like rocks that are forming today in modern Iceland, which is transitional between oceanic and continental crust. In fact, Iceland has been hypothesized as an analog for how continental crusts started to form.

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Huge Mars Lakes Formed Much More Recently Than Thought

Huge Mars Lakes Formed Much More Recently Than Thought | Amazing Science | Scoop.it

Mars may have been able to support life for much longer than scientists had thought. Some Red Planet streams and lakes — including one bigger than several of North America's Great Lakes — formed just 2 billion to 3 billion years ago, a new study suggests. That's a surprise, because researchers think that, by that epoch, Mars had already lost most of its atmosphere, and therefore had likely become too cold to host liquid water on its surface.

 

"This paper presents evidence for episodes of water modifying the surface on early Mars for possibly several hundred million years later than previously thought, with some implication that the water was emplaced by snow, not rain," Mars Reconnaissance Orbiter (MRO) project scientist Rich Zurek, of NASA's Jet Propulsion Laboratory in Pasadena, California, said in a statement.

 

Zurek was not part of the study team, which was led by Sharon Wilson of the Smithsonian Institution and the University of Virginia. Wilson and her colleagues studied photos of Mars' northern Arabia Terra region taken by three orbiters — MRO, NASA's Mars Global Surveyor probe and Europe's Mars Express spacecraft.

 

"We discovered valleys that carried water into lake basins," Wilson said in the same statement. "Several lake basins filled and overflowed, indicating there was a considerable amount of water on the landscape during this time."

 

"Considerable amount" indeed: One of the newly discovered lakes was about as big as Lake Tahoe, a body of water on the California-Nevada border that holds about 45 cubic miles (188 cubic kilometers) of water, Wilson said. And this Martian lake overflowed into an enormous basin, dubbed Heart Lake, that held about 670 cubic miles (2,790 cubic km) of water — quite a bit more than Lake Erie and Lake Ontario, two of the five Great Lakes along the Canada-U.S. border, researchers added. (Lake Erie and Lake Ontario hold 116 cubic miles and 393 cubic miles, or 480 and 1,640 cubic km, respectively.

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Scientists reveal most accurate depiction of a dinosaur ever created

Scientists reveal most accurate depiction of a dinosaur ever created | Amazing Science | Scoop.it

Reconstruction is based on studies of a spectacular fossil from China, preserved with skin and pigments intact.

 

For those who don’t know their dinosaurs (or don’t have a small child to haughtily inform them), Psittacosaurus fossils are commonly found across most of Asia. The bipedal adults used their distinctive beaks to nibble through the vegetation of the Cretaceous, more than 100m years ago. The relatively large brain of Psittacosaurus leads scientists to suspect it may have been a relatively smart dinosaur, with complex behaviors. The large eyes hint that it had good vision.

 

The Psittacosaurus specimen Vinther’s team studied is held at the Senkenberg Museum in Frankfurt. It is a complete skeleton from one of the world’s best preserved fossil deposits in China. Named the Jehol Biota, these deposits are a Lagerstätte, from the German for storage place­. They are literally a rocky safehouse for the world’s most well-preserved fossils. There are a handful of Lagerstätte around the world, famed for yielding remains that retain their fossilised soft tissues, feathers, fur, skin and stomach contents. The Senckenburg Psittacosaurus is an exceptional example, even having its cloaca preserved – the multi-purpose opening for excretion, reproduction and urination.

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Chirped laser pulses could deliver high-quality ion beams

Chirped laser pulses could deliver high-quality ion beams | Amazing Science | Scoop.it

Physicists in Sweden have come up with a new way of accelerating ions using intense laser pulses. The technique – which has not yet been tested in the lab – involves bouncing “chirped” pulses from a mirror and promises to deliver much more intense ions beams than existing laser acceleration schemes. With further development, the method could be used to provide high-energy ions for cancer treatment.

 

Beams of ions with energies in the 100–200 MeV range are ideal for treating some cancers because they can be fine-tuned to deposit most of their energy within a tumour, thereby minimizing the damage to nearby healthy tissue. Conventional ion therapy, however, requires big, expensive accelerators and beam-guiding systems, which means that relatively few hospitals have such facilities.

 

Ions can, however, also be accelerated to high energies by firing intense laser pulses at a target, which could lead to smaller and less expensive treatment facilities. The process involves a laser pulse creating a hot plasma in which the heated electrons expand rapidly away from the target, leaving the much more sluggish ions behind. Eventually, a huge electric field builds and this will accelerate ions in the plasma to very high energies.

 

This process is very inefficient and messy, however, and produces ions with a wide range of energies – which is not ideal for cancer therapy. And, because the process is essentially a thermal effect, a large increase in the power of the laser is required to achieve a modest increase in the average energy of the ions.

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Astronomers Find 165 Brown Dwarfs in Solar Neighborhood

Astronomers Find 165 Brown Dwarfs in Solar Neighborhood | Amazing Science | Scoop.it

An international team of astronomers has discovered 165 new ultracool brown dwarfs — objects that have a size between that of a gas giant and that of a small star — within about 160 light-years of the Sun. The paper reporting these results will be published in the Astrophysical Journal (arXiv.org preprint).

 

Brown dwarfs are cool, dim objects that are difficult to detect and hard to classify. Sometimes called failed stars, they are too small to sustain hydrogen fusion reactions at their cores, yet they have star-like attributes. Typically, brown dwarfs have masses between 13 and 80 Jupiters — too massive to be planets, yet they possess some planet-like characteristics.

 

Their temperatures can range from nearly as hot as a star to as cool as a planet. Discovering new brown dwarfs will help astronomers to better quantify the frequency at which they occur both in the solar neighborhood and beyond.

 

Knowing the abundance and distribution of these objects provides key information on the distribution of mass in the Universe, and on the mechanism of brown dwarf formation, for example, whether they form in isolation or instead are ejected from larger planetary systems.

 

To that end, Dr. Jasmin Robert of the Université de Montréal and his colleagues from Canada and the United States believed that although hundreds of ultracool brown dwarfs have already been discovered, the techniques used to identify them were overlooking those with more-unusual compositions, which would not show up in the color-based surveys generally used.

 

So the scientists surveyed 28% of the sky and discovered 165 ultracool brown dwarfs (M, L and T types, with temperatures under 3,500 degrees Fahrenheit, or 1,930 degrees Celsius) in the solar neighborhood.

 

“Everyone will benefit from the study of brown dwarfs, because they can often be found in isolation, which means that we can more easily gather precise data on their properties without a bright star blinding our instruments,” said team member Dr. Jonathan Gagné, from the Carnegie Institution for Science in Washington and the Institute for Research on Exoplanets at the Université de Montréal.

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NASA's THEMIS sees Auroras move to the rhythm of Earth's magnetic field

NASA's THEMIS sees Auroras move to the rhythm of Earth's magnetic field | Amazing Science | Scoop.it

The majestic auroras have captivated humans for thousands of years, but their nature -- the fact that the lights are electromagnetic and respond to solar activity -- was only realized in the last 150 years.

 

Thanks to coordinated multi-satellite observations and a worldwide network of magnetic sensors and cameras, close study of auroras has become possible over recent decades. Yet, auroras continue to mystify, dancing far above the ground to some, thus far, undetected rhythm. Using data from NASA's Time History of Events and Macroscale Interactions during Substorms, or THEMIS, scientists have observed Earth's vibrating magnetic field in relation to the northern lights dancing in the night sky over Canada.

 

THEMIS is a five-spacecraft mission dedicated to understanding the processes behind auroras, which erupt across the sky in response to changes in Earth's magnetic environment, called the magnetosphere.

 

These new observations allowed scientists to directly link specific intense disturbances in the magnetosphere to the magnetic response on the ground. A paper on these findings was published in Nature Physics on Sept. 12, 2016.

 

"We've made similar observations before, but only in one place at a time - on the ground or in space," said David Sibeck, THEMIS project scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, who did not participate in the study. "When you have the measurements in both places, you can relate the two things together."

 

Understanding how and why auroras occur helps us learn more about the complex space environment around our planet. Radiation and energy in near-Earth space can have a variety of effects on our satellites - from disrupting their electronics to increasing frictional drag and interrupting communication or navigation signals. As our dependence on GPS grows and space exploration expands, accurate space weather forecasting becomes ever more important.

 

The space environment of our entire solar system, both near Earth and far beyond Pluto, is determined by the sun's activity, which cycles and fluctuates through time. The solar system is filled with solar wind, the constant flow of charged particles from the sun. Most of the solar wind is deflected from Earth by our planet's protective magnetosphere.

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