Researchers at Oak Ridge National Laboratory have obtained the first direct observations of atomic diffusion inside a bulk material. The research, which could be used to give unprecedented insight into the lifespan and properties of new materials, is published in Physical Review Letters.
Developing the cloak of invisibility would be wonderful, but sometimes simply making an object appear to be something else will do the trick, according to Penn State Univ. engineers. To do this, they employ what they call "illusion coatings," which are made of a thin flexible substrate with copper patterns designed to create the desired result. The metamaterial coatings can function normally while appearing as something else.
A surprising phenomenon has been found in metal nanoparticles: They appear, from the outside, to be liquid droplets, wobbling and readily changing shape, while their interiors retain a perfectly stable crystal configuration. The research team behind the finding says the work could have important implications for the design of components in nanotechnology, such as metal contacts for molecular electronic circuits.
Stanford Univ. engineers have invented a sensor that uses radio waves to detect subtle changes in pressure. Already used to monitor brain pressure in laboratory mice as prelude to possible use with human patients, this pressure-sensing technology relies on a specially designed rubber and could lead to touch-sensitive “skin” for prosthetic devices.
Using a common laboratory filter paper decorated with gold nanoparticles, researchers at Washington Univ. in St. Louis have created a unique platform, known as “plasmonic paper,” for detecting and characterizing even trace amounts of chemicals and biologically important molecules, including explosives, chemical warfare agents, environmental pollutants and disease markers.
When a sturdy material becomes soft and spongy, one usually suspects damage. But this is not always the case, especially in biological cells. By looking at microscopic biopolymer networks, researchers in Germany revealed that such materials soften by undergoing a transition from an entangled spaghetti of filaments to aligned layers of bow-shaped filaments that slide past each other. This finding may explain how other filaments flow.
A long-sought goal of creating particles that can emit a colorful fluorescent glow in a biological environment, and that could be precisely manipulated into position within living cells, has been achieved by a team of researchers at Massachusetts Institute of Technology and several other institutions. The new technology could make it possible to track the position of the nanoparticles as they move within the body or inside a cell.
An emerging class of electrically conductive plastics called "radical polymers” may bring low-cost, transparent solar cells, flexible and lightweight batteries, and ultrathin antistatic coatings for consumer electronics and aircraft. Researchers have established the solid-state electrical properties of one such polymer, called PTMA, which is about 10 times more electrically conductive than common semiconducting polymers.
Researchers have developed a new method for harvesting the energy carried by particles known as “dark” spin-triplet excitons with close to 100% efficiency, clearing the way for hybrid solar cells which could far surpass current efficiency limits. To date, this type of energy transfer had only been shown for “bright” spin-singlet excitons.
A new crystallographic technique, called fast time-resolved crystallography, developed in the U.K. is set to transform scientists’ ability to observe how molecules work. Although this method, also known as Laue crystallography, has previously been possible, it has required advanced instrumentation that is only available at three sites worldwide. Only a handful of proteins have been studied using the traditional technique.
Anyone who has blown a bubble and seen how quickly it pops has first-hand experience on the major challenge in creating stable foams. At its most basic level, foam is a bunch of bubbles squished together. Liquid foams, a state of matter that arises from tiny gas bubbles dispersed in a liquid, are familiar in everyday life, from beer to bathwater. They also are important in commercial products and processes.
It’s a well-known phenomenon in electronics: Shining light on a semiconductor, such as the silicon used in computer chips and solar cells, will make it more conductive. But now researchers have discovered that in a special semiconductor, light can have the opposite effect, making the material less conductive instead. This new mechanism of photoconduction could lead to next-generation excitonic devices.
Axons are the shafts of neurons, on the tips of which connections are made with other neurons or cells. In a new study in Texas, researchers were able to use microfluidic stimulations to change the path of an axon at an angle of up to 90 degrees. The publication adds insight to the long accepted idea that chemical cues are primarily responsible for axonal pathfinding during human development and nervous system regeneration.
Massachusetts Institute of Technology researchers have developed a new way of creating surfaces on which droplets of any desired shape can spontaneously form. They say this approach could lead to new biomedical assay devices and light-emitting diode display screens, among other applications. The new work represents the first time that scientists can control the shape of the contact area of the droplets.
Imagine being able to tune the properties of a solid material just by flashing pulses of light on it. That is one potential payoff of electrons and atoms interacting with ultrashort pulses of light. The technology of ultrafast spectroscopy is a key to understanding this phenomenon and now a new wrinkle to that technology, observations of electron self-energy, has been introduced by Lawrence Berkeley National Laboratory researchers.
Nanoparticles could revolutionize the medical industry, but they must first target a specific region in the body, be trackable, and perform their function at the right moment. Researchers in Japan have made progress in this direction with a new type of nanomaterial: the nanosheet. Specifically, they have designed a strong, stable and optically traceable smart 2-D material that responds to pH, or the acidity or basicity of its environment.
Arrays of tiny conical tips that eject ionized materials are being made at the Massachusetts Institute of Technology. The technology, which harnesses electrostatic forces, has a range of promising applications, such as spinning out nanofibers for use in “smart” textiles or propulsion systems for fist-sized “nanosatellites.” The latest prototype array that generates 10 times the ion current per emitter that previous arrays did.
Individuals in industrial associations, educational institutions and government organizations who are interested in composites, or materials made from constituent materials with different physical or chemical properties, now have free, 24/7 access to simulation tools through an online community with offices in the Purdue Research Park.
You can brush your teeth, and wash yourself and your clothes with a clear conscience. The most common soaps, shampoos and detergents actually pose a minimal risk to the environment. This is the conclusion of a comprehensive survey that covers more than 250 scientific studies over several decades.
The world’s first “solar battery”, invented by researchers at Ohio State Univ., is a battery and a solar cell combined into one hybrid device. Key to the innovation is a mesh solar panel, which allows air to enter the battery, and a special process for transferring electrons between the solar panel and the battery electrode. Inside the device, light and oxygen enable different parts of the chemical reactions that charge the battery.
Nanostructures of virtually any possible shape can now be made using a combination of techniques developed to exploit the unique properties of so-called perovskites. The group based in the Netherlands, developed a pulsed laser deposition technique to create patterns in ultra thin layers, one atomic layer at a time. The perovskites’ crystal structure is undamaged by this soft lithography technique, maintaining electrical conductivity.
Drawn relentlessly by their electrical charges, lithium ions in a battery surge from anode to cathode and back again. Yet, no one really understands what goes on at the atomic scale as lithium ion batteries are used and recharged. Using transmission electron microscopy, researchers are now glimpsing what can happen to anodes as lithium ions work their way into them. The “atomic shuffling” these ions perform leads to rapid anode failure.
A Duke Univ. team has found that nanoparticles called single-walled carbon nanotubes accumulate quickly in the bottom sediments of an experimental wetland setting, an action they say could indirectly damage the aquatic food chain. According to the research, the risk to humans ingesting the particles through drinking water is slight, but aquatic food chains might be harmed by molecules "piggybacking" on the carbon nanoparticles.
Cancer vaccines have recently emerged as a promising approach for killing tumor cells before they spread. But so far, most clinical candidates haven’t worked that well. Now, scientists have developed a new way to deliver vaccines that successfully stifled tumor growth when tested in laboratory mice. And the key is in the vaccine’s unique stealthy nanoparticles.
Ice contains many atoms and molecules trapped inside its structure. A team of Univ. of Chicago and Loyola Univ. researchers has discovered a new mechanism they call "stable energetic embedding" of atoms and molecules within ice. This mechanism explains how some molecules, such as CF4, or "carbon tetrafluoride", interact with and become embedded beneath ice surfaces.