34213801
submission
LilaG writes:
Drug tests spot banned substances based on their chemical structures, but a new breed of narcotics is designed to evade such tests. These synthetic marijuana drugs, found in "herbal incense," are mere chemical tweaks of each other, allowing them to escape detection each time researchers develop a new test for one of the compounds. Now chemists have developed a method that can screen for multiple designer drugs at once, without knowing their structures. The test may help law enforcement crack down on the substances.
The researchers used a technique called "mass defect filtering," which can detect related compounds all at once. That's because related compounds have almost equal numbers to the right of the decimal point in their molecular masses.
The researchers tested their technique on 32 herbal products with names like "Mr. Nice Guy" and "Hot Hawaiian." They found that every product contained one or more synthetic cannabinoid; all told, they identified nine different compounds in them — two illegal ones and seven that are not regulated.
The news story appears in Chemical & Engineering News and the original paper is (behind a paywall) in Analytical Chemistry.
33692975
submission
LilaG writes:
Who hasn't marveled at the ability of water bugs to skate along the surface of lakes and ponds? Now materials scientists in China have taken a cue from water striders and created a device that can coast along the surface between oil and water.
The tricky part was figuring out how to make an oil-repelling surface that worked underwater. It came down to coating copper wires with copper oxide microstructures that look like flowers made up of nanopetals.
Scientists think such coatings could enable robots that clean up oil spills, bug-proof car windshields, and ship hulls that don't build up barnacles.
Check out the photo of the device to see how technology imitates life.
32310407
submission
LilaG writes:
To develop new materials for robotics, scientists have developed graphene-based actuators that convert electricity into motion. In robots, actuators act like muscles, driving the movement of mechanical arms and fins. Most actuator materials, such as ceramics and conductive polymers, respond slowly, require a lot of power, or provide very little force. To make speedy, strong actuators, Chinese researchers coated graphene paper with the polymer polydiacetylene. Graphene provides a highly conductive, flexible backing for the fragile polymer crystals, which deform in response to electrical current. The actuators can bend 200 times per second and generate more force than most current materials. Using a sheet of the material, the scientists built a simple inchworm robot that arches and relaxes to crawl forward.
31338561
submission
LilaG writes:
Chemists in China have precisely grown arrays of ultrathin flakes of bismuth selenide and bismuth telluride on a surface. The bismuth compounds belong to a recently discovered – and weird — class of materials called topological insulators, which conduct electrons only along their surfaces, not through their insides.
Researchers think topological insulators promise a new realm of fast, energy-efficient electronic and spintronic devices. Making well-defined nanoparticle arrays such as the new study’s flakes is a key step towards such devices.
30021031
submission
LilaG writes:
Not just a way to transport trains at high speed, magnetic levitation could find use in diagnosing disease. Researchers at Harvard have shown that they can detect proteins in blood using MagLev. The researchers, led by George Whitesides, use levitation to detect a change in the density of porous gel beads that occurs when a protein binds to ligands inside the beads. The lower the bead levitates, the more protein it holds. The method (abstract of paywalled article) could work for detecting disease proteins in people’s blood samples in the developing world: The magnets cost only about $5 each, and the device requires no electricity or batteries. Because the beads are visible to the naked eye, researchers can make measurements with a simple ruler with a millimeter scale.
29680417
submission
LilaG writes:
Gasoline-burning engines put out twice as much black carbon as was previously measured, according to new field methods tested in Toronto. The tiny particles known as black carbon pack a heavy punch when it comes to climate change, by trapping heat in the atmosphere and by alighting atop, and melting, Arctic ice. With an eye toward controlling these emissions, researchers have tracked black carbon production from fossil fuel combustion in gasoline-burning cars and diesel-burning trucks. Until this study was published, gas-burning vehicles had been thought to be relatively minor players.
