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Submission + - Self-propelled nanoparticles find and repair cracks in electronics

JMarshall writes: Self-propelled nanoparticles autonomously detect surface cracks in circuit wiring and then nestle into the cracks to patch them. To fix a broken circuit, a drop of the nanoparticle-containing solution could be placed on the surface of the circuit without needing to pinpoint the location of the damage.

One hemisphere of each gold nanoparticle is coated with platinum, which catalyzes a reaction with hydrogen peroxide into water that creates a concentration gradient and pushes the particles around. The other hemisphere is coated with a hydrophobic molecule that sticks when it encounters a hydrophobic surface, like the exposed silicon beneath cracks in wiring on a circuit board. When it sticks in the crack site, the gold nanoparticle bridges the gap and current can flow again. Researchers demonstrate that they could fix a circuit and relight an LED within five minutes of applying the particles.

Submission + - Mealworms Eat and Digest Polystyrene Foam (acs.org)

ckwu writes: Polystyrene foams—including products like Styrofoam—are rarely recycled, and the materials biodegrade so slowly that they can sit in a landfill for hundreds of years. But a pair of new studies shows that mealworms will dine on polystyrene foam when they can’t get a better meal, converting almost half of what they eat into carbon dioxide. In one study, the researchers fed mealworms polystyrene foam and found that the critters converted about 48% of the carbon they ate into carbon dioxide and excreted 49% in their feces. In the second study, the researchers showed that bacteria in the mealworms’ guts were responsible for breaking down the polystyrene--suggesting that engineering bacteria might be a strategy for boosting the reported biodegradation.

Submission + - Dormant Virus Wakes Up In Some Patients With Lou Gehrig's Disease (acs.org)

MTorrice writes: Our chromosomes hold a partial record of prehistoric viral infections: About 8% of our genomes come from DNA that viruses incorporated into the cells of our ancestors. Over many millennia, these viral genes have accumulated mutations rendering them mostly dormant.

But one of these viruses can reawaken in some patients with amyotrophic lateral sclerosis (ALS), a progressive muscle wasting disease commonly known as Lou Gehrig’s disease. A new study demonstrates that this so-called endogenous retrovirus can damage neurons, possibly contributing to the neurodegeneration seen in the disease.

The findings raise the possibility that antiretroviral drugs, similar to those used to treat HIV, could slow the progression of ALS in some patients.

Submission + - Easy-To-Clean Membrane Separates Oil From Water (acs.org)

ckwu writes: A steel mesh with a novel self-cleaning coating can separate oil and water, easily lifting oil from an oil-water mixture and leaving the water behind. Unlike existing oil-water separation membranes, if the coated mesh gets contaminated with oil, it can be simply rinsed off with water and reused, without needing to be cleaned with detergents. The team was able to use the mesh to lift crude oil from a crude oil-seawater mixture, showcasing the feasibility of oil-spill cleanup. The membrane could also be used to treat oily wastewater and as a protective barrier in industrial sewer outlets to avoid oil discharge.

Submission + - Printing Flexible Lithium-Ion Batteries (acs.org)

ckwu writes: The designs of pacemakers, watches, and other wearable gadgets have to be tailored around existing battery shapes, such as cylinders, coin cells, and rectangles. But a team of researchers hopes their fully printable, flexible lithium-ion batteries will one day free designers from these constraints. Battery shapes are now limited because of the need to contain liquid electrolytes. Two years ago, the researchers designed a printable, solid-state electrolyte composed of alumina nanoparticles and lithium combined with polymer that can be cured by ultraviolet light. In this latest work, they used a stencil printing technique to print full battery cells with the electrolyte and other printable materials for the electrodes. They printed batteries on paper and the curved surface of a glass mug. These printed Li-ion batteries can power small LEDs but still need a lot of improvements because they don't last long before needing recharging.

Submission + - Transparent Paper Produces Power With Just A Touch (acs.org)

ckwu writes: A new transparent-paper device can generate electrical power from a user’s touch. The paper energy-harvester could be used to make disposable, self-powered touch screens that fold; interactive light-up books; touch-sensitive skin for prosthetics; and security systems for art and documents, according to the researchers. The device is made out of nanopaper, a tangled mat made of nanometers-wide cellulose fibers that is transparent and smooth like plastic. The researchers deposit carbon nanotubes on the nanopaper to make a pair of electrodes, and then sandwich a polyethylene film in between. The generator works via electrostatic induction. Pressing one side of the device causes a change in the charge balance between the nanotube electrodes, resulting in a flow of current through the device. Releasing the pressure causes electrons to flow back, so repeated pressing and releasing creates continuous current. The researchers demonstrated that the generator could produce enough power when pressed to light up a small liquid-crystal display.

Submission + - Airplane Coatings Help Recoup Fuel Efficiency Lost To Bug Splatter (acs.org)

MTorrice writes: When bugs explode against the wings of oncoming airplanes, they create a sticky problem for aerospace engineers. Their blood, or hemolymph, clings to an airplane’s wings, disrupting the smooth airflow over them and sapping the aircraft’s fuel efficiency. NASA scientists are now developing coatings that help aircraft shed or repel bug guts during flight. After screening nearly 200 different coating formulations, the NASA researchers recently flight-tested a handful of promising candidates, showing that they could reduce the amount of insect insides stuck to the wings by up to 40%. With further optimization, such coatings could allow planes to use 5% less fuel.

Submission + - Generating Power With Bacterial Spores (acs.org)

MTorrice writes: Ozgur Sahin dreams of a future when panels floating on lakes and oceans generate renewable energy. But the panels the biophysicist from Columbia University has in mind don’t harvest wind or sunlight. They use bacterial spores to tap the power of evaporating water.

In a step toward that goal, Sahin and his team have created machines that produce electricity when spore-laden materials—a sort of artificial muscle—expand and contract with changes in humidity. Although these devices generate only about 1% of the energy produced by similarly sized commercial solar panels, the spore-powered generators cost about 100 times less, Sahin says.

Watch the spore muscles power a LED and a little car.

Submission + - An extra-large nanocage molecule for quantum computing

JMarshall writes: Researchers have built a molecular nanocage 8 nm across that represents a step toward quantum computing.
It is difficult to make uniform nanoparticles more than 4 nm across, but new work solves this problem. Researchers made eight-membered metal rings from chromium and nickel that can act like a qubits in quantum computing. More connected rings means greater quantum computing capacity, so the team worked to combine many rings into one molecule. They managed to pull 24 rings together into an 8-nm sphere, secured by palladium ions at the core. The molecule had a surprisingly good phase memory, an indication of the molecule’s quantum computing potential. The researchers say building a molecule with 70-100 rings would allow them to do “some serious stuff” in quantum computing.

Submission + - Coating Stabilizes Lithium Electrodes For High Capacity Batteries

JMarshall writes: Lithium-metal battery anodes can store 10-fold more energy by weight than those in today’s best batteries, but they have been too unstable to be practical. Now, researchers have used atomic layer deposition—widely used in the semiconductor industry—to coat lithium-metal anodes with a thin protective layer that dramatically improved their performance. Coated lithium-metal anodes did not corrode under conditions that corrode unprotected lithium metal. When combined with sulfur cathodes, which also have the potential to store lots of energy but which typically react badly with lithium, the lithium metal anodes performed well with no sign of degradation after 100 charge cycles. If these better batteries could be commercialized, they could allow electric vehicles to drive farther between charges or offer a more compact power source for implanted medical devices.

Submission + - First Ultraviolet Quantum Dots Shine In An LED (acs.org)

ckwu writes: Researchers in South Korea have made the first quantum dots that emit ultraviolet light and used them to make a flexible, light-emitting diode. Until now, no one had succeeded in making quantum dots that emit wavelengths shorter than about 400 nm, which marks the high end of the UV spectrum. To get quantum dots that emit UV, the researchers figured out how make them with light-emitting cores smaller than 3 nm in diameter. They did it by coating a light-emitting cadmium zinc selenide nanoparticle with a zinc sulfide shell, which caused the core to shrink to 2.5 nm. The quantum dots give off true UV light, at 377 nm. An LED made with the quantum dots could illuminate the anticounterfeiting marks on a paper bill. If their lifetimes can be improved, these potentially low-cost UV LEDs could find uses in counterfeit currency detection, water sterilization, and industrial applications.

Submission + - Dissolvable Electronic Stent Can Monitor Blocked Arteries (acs.org)

ckwu writes: To restore blood flow in a narrowed or blocked artery, doctors can implant a metal stent to hold open the vessel. But over time, stents can cause inflammation and turbulent blood flow that lead to new blockages. Now, researchers have designed a stent carrying a suite of onboard electronic blood-flow and temperature sensors, drug delivery particles, data storage, and communication capabilities to detect and overcome these problems. The entire device is designed to dissolve as the artery heals. Medical device companies and cardiologists could look at this electronic stent as a kind of menu from which they can pick whatever components are most promising for treating certain kinds of cardiovascular disease, the researchers say.

Submission + - Tiny Capsules Tailor Light (acs.org)

ckwu writes: Dyes that can convert low-energy and ambient light to higher energy green or blue light could help boost the efficiency of solar cells and enable new kinds of medical imaging and light-based therapies. In a step that could help make these so-called upconverters more practical, researchers have demonstrated a way to encapsulate the dyes within particles. They make the particles with a microfluidic system that traps a droplet of a solution of upconversion dyes within three protective layers: a surfactant to help stabilize the droplet, a thin layer of water, and a polymer shell. These triple-layer coatings protect the sensitive dyes from oxygen without dimming their light.

Submission + - Making Legal Marijuana Safe (acs.org)

MTorrice writes: Where once the use of Cannabis strains such as banana kush, Dr. Greenthumb’s ghost, and gorilla glue #4 was hidden behind closed doors, it is now increasingly in the open. Four states—Colorado, Washington, Alaska, and Oregon—have legalized both recreational and medicinal use, and another 19 allow medicinal use only. With that openness, however, comes new challenges in the form of safety concerns and evolving regulations to protect production workers and consumers. Companies are working on those issues, in particular finding ways to safely extract cannabinoids and other compounds from the plant material to yield concentrated oils and waxes used in vaporizers, foods, salves, or other products.

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