Spikes Of Graphene Can Kill Bacteria On Implants

Researchers develop ‘self-healing’ robotics material

Image: Victor Habbick Visions/Science Photo Library

Traditional electronics are made from rigid and brittle materials. However, a new ‘self-healing’ electronic material allows a soft robot to recover its circuits after it is punctured, torn or even slashed with a razor blade.

Made from liquid metal droplets suspended in a flexible silicone elastomer, it is softer than skin and can stretch about twice its length before springing back to its original size.

Soft Robotics & Biologically Inspired Robotics at Carnegie Mellon University. Video: Mouser Electronics 

‘The material around the damaged area automatically creates new conductive pathways, which bypass the damage and restore connectivity in the circuit,’ explains first author Carmel Majidi at Carnegie Mellon University in Pittsburgh, Pennsylvania. The rubbery material could be used for wearable computing, electronic textiles, soft field robots or inflatable extra-terrestrial housing.

‘There is a sweet spot for the size of the droplets,’ says Majidi. ‘We had to get the size not so small that they never rupture and form electronic connections, but not so big they would rupture even under light pressure.’

To read the full article, by Anthony King, in C&I, the members’ magazine for SCI, click here. 

Polymer researchers discover path to sustainable and biodegradable polyesters

There’s a good chance you’ve touched something made out of the polyolefin polymer today. It’s often used in polyethylene products like plastic bags or polypropylene products like diapers.

As useful as polyolefins are in society, they continue to multiply as trash in the environment. Scientists estimate plastic bags, for example, will take centuries to degrade.

But now, researchers at Virginia Tech have synthesized a biodegradable alternative to polyolefins using a new catalyst and the polyester polymer, and this breakthrough could eventually have a profound impact on sustainability efforts.

Rong Tong, assistant professor in the Department of Chemical Engineering and affiliated faculty member of Macromolecules Innovation Institute (MII), led the team of researchers, whose findings were recently published in the journal Nature Communications.

One of the largest challenges in polymer chemistry is controlling the tacticity or the stereochemistry of the polymer. When multiplying monomer subunits into the macromolecular chain, it’s difficult for scientists to replicate a consistent arrangement of side-chain functional groups stemming off the main polymer chain. These side-chain functional groups greatly affect a polymer’s physical and chemical properties, such as melting temperature or glass-transition temperature, and regular stereochemistry leads to better properties.

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CRISP(ie)R news than anything!

Enzyme tweak boosts precision of CRISPR genome edits

Engineered enzyme drives genome-editing errors below detection limit.

A powerful technique for editing genomes is now more precise. By tweaking an enzyme, researchers have reduced the error rate for the technique, known as CRISPR–Cas9 — in some cases to undetectable levels, they report on 6 January in Nature1.

Researchers use CRISPR–Cas9 to make precise changes to genomes that remove or edit a faulty gene. It has worked on nearly every creature on which they have tested it, including human embryos.

The technique relies on an enzyme called Cas9, that uses a ‘guide RNA’ molecule to home in on its target DNA. Cas9 cuts the DNA at that site, and the cell’s natural DNA repair machinery then takes over to mend the cut — deleting a short fragment of DNA or stitching in a new sequence in the process.

But the technology is not infallible: sometimes the Cas9 enzyme creates unwanted mutations. As CRISPR inches out of the laboratory and towards the clinic — with debates raging overwhether it should be deployed in embryos — researchers have pushed to reduce the error rate.

The latest study moves the field closer to that goal, says lead author Keith Joung, a pathologist at Massachusetts General Hospital in Boston. “This is a significant move forward,” he says. “We can very much reduce the probability of off-targets.”

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Eye o' Sofia

Chasing the Shadow of Neptune’s Moon Triton

Our Flying Observatory

Our flying observatory, called SOFIA, carries a 100-inch telescope inside a Boeing 747SP aircraft. Scientists onboard study the life cycle of stars, planets (including the atmosphere of Mars and Jupiter), nearby planetary systems, galaxies, black holes and complex molecules in space.

AND on Oct. 5, SOFIA is going on a special flight to chase the shadow of Neptune’s moon Triton as it crosses Earth’s surface!

In case you’re wondering, SOFIA stands for: Stratospheric Observatory for Infrared Astronomy.

Triton

Triton is 1,680 miles (2,700 km) across, making it the largest of the 13 moons orbiting Neptune. Unlike most large moons in our solar system, Triton orbits in the opposite direction of Neptune, called a retrograde orbit. This backward orbit leads scientists to believe that Triton formed in an area past Neptune, called the Kuiper Belt, and was pulled into its orbit around Neptune by gravity. 

The Voyager 2 spacecraft flew past Neptune and Triton in 1989 and found that Triton’s atmosphere is made up of mostly nitrogen…but it has not been studied in nearly 16 years!

Occultations are Eclipse-Like Events

An occultation occurs when an object, like a planet or a moon, passes in front of a star and completely blocks the light from that star. As the object blocks the star’s light, it casts a faint shadow on Earth’s surface. 

But unlike an eclipse, these shadows are not usually visible to the naked eye because the star and object are much smaller and not nearly as bright as our sun. Telescopes with special instruments can actually see these shadows and study the star’s light as it passes near and around the object – if they can be in the right place on Earth to catch the shadow.

Chasing Shadows

Scientists have been making advanced observations of Triton and a background star. They’ve calculated exactly where Triton’s faint shadow will fall on Earth! Our SOFIA team has designed a flight path that will put SOFIA (the telescope and aircraft) exactly in the center of the shadow at the precise moment that Triton and the star will align. 

This is no easy feat because the shadow is moving at more than 53,000 mph while SOFIA flies at Mach 0.85 (652 mph), so we only have about two minutes to catch the shadow!! But our SOFIA team has previously harnessed the aircraft’s mobility to study Pluto from inside the center of its occultation shadow, and is ready to do it again to study Triton!

What We Learn From Inside the Shadow

From inside the shadow, our team on SOFIA will study the star’s light as it passes around and through Triton’s atmosphere. This allows us to learn more about Triton’s atmosphere, including its temperature, pressure, density and composition! 

Our team will use this information to examine if Triton’s atmosphere has changed since our Voyager 2 spacecraft flew past it in 1989. That’s a lot of information from a bit of light inside a shadow! Similar observations of Uranus in 1977, from our previous flying observatory, led to the discovery of rings around that planet!

International Ground-Based Support

Ground-based telescopes across the United States and Europe – from Scotland to the Canary Islands – will also be studying Triton’s occultation. Even though most of these telescopes will not be in the center of the shadow, the simultaneous observations, from different locations on Earth, will give us information about how Triton’s atmosphere varies across its latitudes. 

This data from across the Earth and from onboard SOFIA will help researchers understand how Triton’s atmosphere is distorted at different locations by its high winds and its strong tides!

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.

Eric Magnus Lensherr-sphere

Magnetospheres: How Do They Work?

The sun, Earth, and many other planets are surrounded by giant magnetic bubbles.

Space may seem empty, but it’s actually a dynamic place, dominated by invisible forces, including those created by magnetic fields.  Magnetospheres – the areas around planets and stars dominated by their magnetic fields – are found throughout our solar system. They deflect high-energy, charged particles called cosmic rays that are mostly spewed out by the sun, but can also come from interstellar space. Along with atmospheres, they help protect the planets’ surfaces from this harmful radiation.

It’s possible that Earth’s protective magnetosphere was essential for the development of conditions friendly to life, so finding magnetospheres around other planets is a big step toward determining if they could support life.

But not all magnetospheres are created equal – even in our own backyard, not all planets in our solar system have a magnetic field, and the ones we have observed are all surprisingly different.

Earth’s magnetosphere is created by the constantly moving molten metal inside Earth. This invisible “force field” around our planet has an ice cream cone-like shape, with a rounded front and a long, trailing tail that faces away from the sun. The magnetosphere is shaped that way because of the constant pressure from the solar wind and magnetic fields on the sun-facing side.

Earth’s magnetosphere deflects most charged particles away from our planet – but some do become trapped in the magnetic field and create auroras when they rain down into the atmosphere.

We have several missions that study Earth’s magnetosphere – including the Magnetospheric Multiscale mission, Van Allen Probes, and Time History of Events and Macroscale Interactions during Substorms (also known as THEMIS) – along with a host of other satellites that study other aspects of the sun-Earth connection.

Mercury, with a substantial iron-rich core, has a magnetic field that is only about 1% as strong as Earth’s. It is thought that the planet’s magnetosphere is stifled by the intense solar wind, limiting its strength, although even without this effect, it still would not be as strong as Earth’s. The MESSENGER satellite orbited Mercury from 2011 to 2015, helping us understand our tiny terrestrial neighbor.

After the sun, Jupiter has by far the biggest magnetosphere in our solar system – it stretches about 12 million miles from east to west, almost 15 times the width of the sun. (Earth’s, on the other hand, could easily fit inside the sun.) Jupiter does not have a molten metal core like Earth; instead, its magnetic field is created by a core of compressed liquid metallic hydrogen.

One of Jupiter’s moons, Io, has intense volcanic activity that spews particles into Jupiter’s magnetosphere. These particles create intense radiation belts and the large auroras around Jupiter’s poles.

Ganymede, Jupiter’s largest moon, also has its own magnetic field and magnetosphere – making it the only moon with one. Its weak field, nestled in Jupiter’s enormous shell, scarcely ruffles the planet’s magnetic field.

Our Juno mission orbits inside the Jovian magnetosphere sending back observations so we can better understand this region. Previous observations have been received from Pioneers 10 and 11, Voyagers 1 and 2, Ulysses, Galileo and Cassini in their flybys and orbits around Jupiter.

Saturn’s moon Enceladus transforms the shape of its magnetosphere. Active geysers on the moon’s south pole eject oxygen and water molecules into the space around the planet. These particles, much like Io’s volcanic emissions at Jupiter, generate the auroras around the planet’s poles. Our Cassini mission studies Saturn’s magnetic field and auroras, as well as its moon Enceladus.

Uranus’ magnetosphere wasn’t discovered until 1986 when data from Voyager 2’s flyby revealed weak, variable radio emissions. Uranus’ magnetic field and rotation axis are out of alignment by 59 degrees, unlike Earth’s, whose magnetic field and rotation axis differ by only 11 degrees. On top of that, the magnetic field axis does not go through the center of the planet, so the strength of the magnetic field varies dramatically across the surface. This misalignment also means that Uranus’ magnetotail – the part of the magnetosphere that trails away from the sun – is twisted into a long corkscrew.

Neptune’s magnetosphere is also tilted from its rotation axis, but only by 47. Just like on Uranus, Neptune’s magnetic field strength varies across the planet. This also means that auroras can be seen away from the planet’s poles – not just at high latitudes, like on Earth, Jupiter and Saturn.

Does Every Planet Have a Magnetosphere?

Neither Venus nor Mars have global magnetic fields, although the interaction of the solar wind with their atmospheres does produce what scientists call an “induced magnetosphere.” Around these planets, the atmosphere deflects the solar wind particles, causing the solar wind’s magnetic field to wrap around the planet in a shape similar to Earth’s magnetosphere.

What About Beyond Our Solar System?

Outside of our solar system, auroras, which indicate the presence of a magnetosphere, have been spotted on brown dwarfs – objects that are bigger than planets but smaller than stars.

There’s also evidence to suggest that some giant exoplanets have magnetospheres. As scientists now believe that Earth’s protective magnetosphere was essential for the development of conditions friendly to life, finding magnetospheres around exoplanets is a big step in finding habitable worlds.  

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

Vacuuma Matata

SOS Save our sounds

AI-based method could speed development of specialized nanoparticles

A new technique developed by MIT physicists could someday provide a way to custom-design multilayered nanoparticles with desired properties, potentially for use in displays, cloaking systems, or biomedical devices. It may also help physicists tackle a variety of thorny research problems, in ways that could in some cases be orders of magnitude faster than existing methods.

The innovation uses computational neural networks, a form of artificial intelligence, to “learn” how a nanoparticle’s structure affects its behavior, in this case the way it scatters different colors of light, based on thousands of training examples. Then, having learned the relationship, the program can essentially be run backward to design a particle with a desired set of light-scattering properties – a process called inverse design.

The findings are being reported in the journal Science Advances, in a paper by MIT senior John Peurifoy, research affiliate Yichen Shen, graduate student Li Jing, professor of physics Marin Soljacic, and five others.

Read more.

The perfect news in EVERY WAY.

I have nothing to do with this mission, but damn do I feel proud. What peculiar beings we, humans, are. Sending into space a doll in a spacesuit, named “Starman”, seated in an electric car, with a sign “Don’t Panic” on the car’s dashboard, blasting David Bowie’s “Life On Mars?”. I’m not crying, you are.

@neysastudies

Toxic ‘zombie’ cells seen for 1st time in Alzheimer’s

A type of cellular stress known to be involved in cancer and aging has now been implicated, for the first time, in Alzheimer’s disease. UT Health San Antonio faculty researchers reported the discovery in the journal Aging Cell.

The team found that the stress, called cellular senescence, is associated with harmful tau protein tangles that are a hallmark of 20 human brain diseases, including Alzheimer’s and traumatic brain injury. The researchers identified senescent cells in postmortem brain tissue from Alzheimer’s patients and then found them in postmortem tissue from another brain disease, progressive supranuclear palsy.

Cellular senescence allows the stressed cell to survive, but the cell may become like a zombie, functioning abnormally and secreting substances that kill cells around it. “When cells enter this stage, they change their genetic programming and become pro-inflammatory and toxic,” said study senior author Miranda E. Orr, Ph.D., VA research health scientist at the South Texas Veterans Health Care System, faculty member of the Sam and Ann Barshop Institute for Longevity and Aging Studies, and instructor of pharmacology at UT Health San Antonio. “Their existence means the death of surrounding tissue.”

Improvements in brain structure and function

The team confirmed the discovery in four types of mice that model Alzheimer’s disease. The researchers then used a combination of drugs to clear senescent cells from the brains of middle-aged Alzheimer’s mice. Such drugs are called senolytics. The drugs used by the San Antonio researchers are dasatinib, a chemotherapy medication that is U.S. Food and Drug Administration-approved to treat leukemia, and quercetin, a natural flavonoid compound found in fruits, vegetables and some beverages such as tea.

After three months of treatment, the findings were exciting. “The mice were 20 months old and had advanced brain disease when we started the therapy,” Dr. Orr said. “After clearing the senescent cells, we saw improvements in brain structure and function. This was observed on brain MRI studies (magnetic resonance imaging) and postmortem histology studies of cell structure. The treatment seems to have stopped the disease in its tracks.”

“The fact we were able to treat very old mice and see improvement gives us hope that this treatment might work in human patients even after they exhibit symptoms of a brain disease,” said Nicolas Musi, M.D., study first author, who is Professor of Medicine and Director of the Sam and Ann Barshop Institute at UT Health San Antonio. He also directs the VA-sponsored Geriatric Research, Education and Clinical Center (GRECC) in the South Texas Veterans Health Care System.

Typically, in testing an intervention in Alzheimer’s mice, the therapy only works if mice are treated before the disease starts, Dr. Musi said.

Tau protein accumulation is responsible

In Alzheimer’s disease, patient brain tissue accumulates tau protein tangles as well as another protein deposit called amyloid beta plaques. The team found that tau accumulation was responsible for cell senescence. Researchers compared Alzheimer’s mice that had only tau tangles with mice that had only amyloid beta plaques. Senescence was identified only in the mice with tau tangles.

In other studies to confirm this, reducing tau genetically also reduced senescence. The reverse also held true. Increasing tau genetically increased senescence.

Importantly, the drug combination reduced not only cell senescence but also tau tangles in the Alzheimer’s mice. This is a drug treatment that does not specifically target tau, but it effectively reduced the tangle pathology, Dr. Orr said.

“When we looked at their brains three months later, we found that the brains had deteriorated less than mice that received placebo control treatment,” she said. “We don’t think brain cells actually grew back, but there was less loss of neurons, less brain ventricle enlargement, improved cerebral blood flow and a decrease in the tau tangles. These drugs were able to clear the tau pathology.”

Potentially a therapy to be tested in humans

“This is the first of what we anticipate will be many studies to better understand this process,” Dr. Musi said. “Because these drugs are approved for other uses in humans, we think a logical next step would be to start pilot studies in people.”

The drugs specifically target—and therefore only kill—the senescent cells. Because the drugs have a short half-life, they are cleared quickly by the body and no side effects were observed.

Dasatinib is an oral medication. The mice were treated with the combination every other week. “So in the three months of treatment, they only received the drug six times,” Dr. Orr said. “The drug goes in, does its job and is cleared. Senescent cells come back with time, but we expect that it would be possible to take the drug again and be cleared out again. That’s a huge benefit—it wouldn’t be a drug that people would have to take every day.”

Dosage and frequency in humans would need to be determined in clinical trials, she said.

Next, the researchers will study whether cell senescence is present in traumatic brain injury. TBI is a brain injury that develops tau protein accumulation and is a significant cause of disability in both military and non-military settings, Dr. Orr said.