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Submission + - Deep-Frying Graphene Microspheres For Energy Storage (acs.org)

Submitted by ckwu
ckwu writes: Materials scientists have constructed round, pom-pom-like graphene microparticles by spraying graphene oxide droplets into a hot solvent—a process akin to deep-frying. The technique could provide a simple, versatile means to make electrode materials for batteries and supercapacitors, possibly leading to devices with improved energy and power densities, the researchers say. The microparticles contain graphene nanosheets radiating out from their centers, which increases the exposed surface area of the graphene and creates open nanochannels that can enhance charge transfer. Electrodes made with the graphene microspheres had higher capacitance than those made with unassembled graphene sheets, demonstrating that the 3-D structure of the particles improved performance.

Submission + - Record-Breaking Nanowire Transistors (acs.org)

Submitted by MTorrice
MTorrice writes: With the functional size limit for silicon transistors fast approaching, researchers are working on transistor designs that rely on materials with better electrical properties than silicon. Now researchers have made high-performance transistors from a promising candidate material: gallium arsenide nanowires.

GaAs is a III/V semiconductor—each member of the family contains an element from the third and fifth columns of the periodic table. These materials have higher charge mobility than silicon, which should allow III/V transistors to switch on and off faster than silicon-based devices.

The nanowire transistors have fast switching speeds, turning on and off 75 billion times a second, or at 75 GHz. The previous record for planar nanowire transistors was 1.8 GHz.
 

Submission + - Flexible White Organic LEDs Achieve Record Efficiencies (acs.org)

Submitted by MTorrice
MTorrice writes: One challenge for achieving high-efficiency organic light-emitting diodes (OLEDs) is making flexible transparent electrodes. The brittle indium tin oxide (ITO) electrodes used in conventional glass devices cannot be used in bendable applications such as roll-up displays. So researchers have explored electrodes made of carbon nanotubes, graphene, and silver nanowires. Now materials scientists have built large, flexible organic light-emitting diodes (OLEDs) that shine white light with record-high efficiency thanks to a new method for making transparent electrodes with silver networks.

The embedded silver electrodes are highly transparent, transmitting more than 88% of light hitting them. They also have a low electrical resistance of 4.7 ohms per square, which is better than the 15 to 20 ohms per square of other reported silver nanowire electrodes, or even ITO-based ones.

Submission + - U.S. Passenger Vehicle Fleet Dirtier After 2008 Recession (acs.org)

Submitted by MTorrice
MTorrice writes: The 2008 recession hammered the U.S. auto industry, driving down sales of 2009 models to levels 35% lower than those before the economic slump. A new study has found that because sales of new vehicles slowed, the average age of the U.S. fleet climbed more than expected, increasing the rate of air pollutants released by the fleet.

In 2013, the researchers studied the emissions of more than 68,000 vehicles on the roads in three cities—Los Angeles, Denver, and Tulsa. They calculated the amount of pollution released per kilogram of fuel burned for the 2013 fleet and compared the rates to those that would have occurred if the 2013 fleet had the same age distribution as the prerecession fleet. For the three cities, carbon monoxide emissions were greater by 17 to 29%, hydrocarbons by 9 to 14%, nitrogen oxide emissions by 27 to 30%, and ammonia by 7 to 16%.

Submission + - Pantry Pests Harbor Plastic-Chomping Bacteria (acs.org)

Submitted by MTorrice
MTorrice writes: In the U.S. alone, consumers discard over 32 million tons of plastic each year, only 9% of which is recycled. Polyethylene is one of the most popular and, unfortunately, persistent types of plastics. Bags, bottles, and packaging made from the polymer accumulate in landfills and oceans across the globe. Scientists have lamented that the material isn't biodegradable because microbes can’t chew up the plastic to render it harmless. However, a new study reports the first definitive molecular evidence that two species of bacteria, found in the guts of a common pantry pest, can thrive on polyethylene and break it apart.

Submission + - European Nations Release Troubling Levels Of Chemicals (acs.org)

Submitted by MTorrice
MTorrice writes: An ecological footprint is a popular metric that shows the amount of natural resources required to provide raw materials and food to sustain an individual or a country. Comparing the footprint to what nature actually can provide allows people to easily grasp their impact on the environment.

Now, researchers report the first methods for calculating a chemical footprint to explain how the mix of chemicals released into the environment affects ecosystem health. The footprint describes how much freshwater is needed to dilute all of the chemicals released by a country to safe levels.

Analyses using these indicators suggest that most European countries don’t have enough freshwater in their rivers and lakes to dilute their chemical pollution to safe levels for their aquatic ecosystems.

Submission + - Researchers Direct Growth Of Neurons With Silicon Nitride Microtubes (acs.org)

Submitted by MTorrice
MTorrice writes: Bioengineers want to connect electronics and neurons to make devices such as new cochlear implants or prosthetic limbs with a seemingly natural sense of touch. They also could build synthetic neural circuitry to use to study how the brain processes information or what goes wrong in neurodegenerative diseases.

As a step toward these applications, a team of researchers has developed a way to direct the growth of axons, the connection-forming arms of neurons. They use transparent silicon nitride microtubes on glass slides to encourage the cells’ axons to grow in specific directions. The cultured nerve cells grow aimlessly until they bump into one of the tubes. The axon then enters the tube, and its growth is accelerated 20-fold.

Silicon nitride already is used in some orthopedic devices, and could serve as a substrate for electronics to interface with the growing neurons.

 

Comment Re:Nature scraping (Score 5, Informative) 77

Usually the compound in your pill is not the compound someone fished out of a microbe. It's been modified to give it better pharmacological properties--last longer in your bloodstream--and to avoid toxicity issues. So there is a lot of intellectual work that goes into making the compound you ingest even if the initial inspiration came from a fungus.

Comment Re:Nature scraping (Score 4, Insightful) 77

No one takes a molecule from a bacterium or fungus and then starts giving it to patients. You have to find the specific compound that allows the fungus/bacterium to kill its neighbors--a very labor intensive process. Then you have to get its structure. Then you test it to see if is druggable--will it last long enough in the bloodstream to be effective, for example. It probably isn't, so then you need to synthesize analogs and test them. Then you have to test it for toxicity, maybe synthesize more analogs to get around toxicity problems. And then you can start clinical trials--three rounds of them usually. Somewhere along the way you need to devise a way to make the compound in large enough quantities to turn it into a pill or injection or whatever deliverable form you're picking. So there are a lot of steps between "hey this compound from this fungus killed that bacteria," and "take this pill once a day for 10 days."

Submission + - Chemists Grow Soil Fungus On Cheerios, Discover New Antifungal Compounds (acs.org)

Submitted by MTorrice
MTorrice writes: Many drugs that treat bacterial and fungal infections were found in microbes growing in the dirt. These organisms synthesize the compounds to fend off other bacteria and fungi around them. To find possible new drugs, chemists try to coax newly discovered microbial species to start making their arsenal of antimicrobial chemicals in the lab. But fungi can be stubborn, producing just a small set of already-known compounds.

Now, one team of chemists has hit upon a curiously effective and consistent trick to prod the organisms to start synthesizing novel molecules: Cheerios inside bags. Scientists grew a soil fungus for four weeks in a bag full of Cheerios and discovered a new compound that can block biofilm formation by an infectious yeast. The chemists claim that Cheerios are by far the best in the cereal aisle at growing chemically productive fungi.

Submission + - Antiperspirants Could Be Source Of Some Particulate Pollution (acs.org)

Submitted by MTorrice
MTorrice writes: Environmental scientists monitor particulate matter pollution because it poses risks to human health and can affect the climate. Ultrafine particles, up to 100 nm in diameter, are produced by vehicle exhaust and other combustion processes. They also form when volatile chemicals from other sources condense in the atmosphere, often through reactions triggered by sunlight.

Now atmospheric scientists propose that personal care products, such as antiperspirants, could be a potential source of ultrafine particulate matter. On the basis of data from the U.S. and Finland, they find that airborne nanoparticles in highly populated areas often contain silicon. They hypothesize that organic silicon compounds found in cosmetics waft into the air, get oxidized, and contribute to the growth of nanoparticles.

Submission + - Magnetic Fields Help Transform Adult Mouse Cells Into Stem Cells (acs.org)

Submitted by MTorrice
MTorrice writes: Biologists have been building up evidence that magnetic fields affect living things in some ways. For example, plants and amphibian embryos develop abnormally when shielded from Earth’s geomagnetic field. Now, for the first time, an international team reports that low-strength magnetic fields may foster the transformation of adult cells into pluripotent stem cells. In fact, when the researchers blocked the Earth's natural magnetic field, the cells couldn't undergo the transformation at all. If confirmed, the phenomenon could lead to new tools for tissue engineering and help researchers understand the potential health effects of changing magnetic fields on astronauts.

Submission + - Engineers Build Ultrasmall Organic Laser (acs.org)

Submitted by ckwu
ckwu writes: Researchers have made the tiniest organic laser reported to date. The 8-micrometer-long, 440-nanometer-wide device, which looks like a suspended bridge riddled with holes, is carved into a silicon chip coated with an organic dye. Integrated into microprocessors, such tiny lasers could one day speed up computers by shuttling data using light rather than electrons. The new organic laser is optically pumped—that is, powered by pulses from another laser. But it has a very low threshold—the energy required to start lasing—of 4 microjoules per square centimeter. The low threshold brings the device closer to engineers’ ultimate goal of creating an organic laser that can run on electric current, which would be key for on-chip use.

Submission + - Strong And Springy Materials Made In The Freezer (acs.org)

Submitted by MTorrice
MTorrice writes: Many strong, porous inorganic materials, such as silica aerogels and metal foams, currently find use in insulation, aircraft wings, and battery electrodes. But these lightweight materials are brittle. Compress them too much and they crack or crumble. Now researchers have developed a one-step freezing method to make porous inorganic materials that can spring back after being squeezed to 15% of their original size. Basically, they freeze a mixture of inorganic particles and a polymer solution and then thaw it after the material has set. These ultralight elastic materials could find use in tissue-engineering scaffolds, biomedical implants, and electronics.

Submission + - Researchers Report Largest DNA Origami To Date (acs.org)

Submitted by MTorrice
MTorrice writes: Bioengineers can harness DNA’s remarkable ability to self-assemble to build two- and three-dimensional nanostructures through DNA origami. Until now, researchers using this approach have been limited to building structures that are tens of square nanometers in size. Now a team reports the largest individual DNA origami structures to date, which reach sizes of hundreds of square nanometers. What’s more, they have developed a less expensive way to synthesize the DNA strands needed, overcoming a tremendous obstacle to scaling up the technology.

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"The fundamental principle of science, the definition almost, is this: the sole test of the validity of any idea is experiment." -- Richard P. Feynman

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