Stanford University scientists have created a new carbon material that significantly boosts the performance of energy-storage technologies. Their results are featured on the cover of the journal ("Ultrahigh Surface Area Three-Dimensional Porous Graphitic Carbon from Conjugated Polymeric Molecular Framework"). 
A new 'designer carbon' invented by Stanford scientists significantly improved the power delivery rate of this supercapacitor. "We have developed a 'designer carbon' that is both versatile and controllable," said Zhenan Bao, the senior author of the study and a professor of chemical engineering at Stanford. "Our study shows that this material has exceptional energy-storage capacity, enabling unprecedented performance in lithium-sulfur batteries and supercapacitors." According to Bao, the new designer carbon represents a dramatic improvement over conventional activated carbon, an inexpensive material widely used in products ranging from water filters and air deodorizers to energy-storage devices. "A lot of cheap activated carbon is made from coconut shells," Bao said. "To activate the carbon, manufacturers burn the coconut at high temperatures and then chemically treat it." The activation process creates nanosized holes, or pores, that increase the surface area of the carbon, allowing it to catalyze more chemical reactions and store more electrical charges. But activated carbon has serious drawbacks, Bao said. For example, there is little interconnectivity between the pores, which limits their ability to transport electricity. "With activated carbon, there's no way to control pore connectivity," Bao said. "Also, lots of impurities from the coconut shells and other raw starting materials get carried into the carbon. As a refrigerator deodorant, conventional activated carbon is fine, but it doesn't provide high enough performance for electronic devices and energy-storage applications." 3-D networks Instead of using coconut shells, Bao and her colleagues developed a new way to synthesize high-quality carbon using inexpensive - and uncontaminated - chemicals and polymers. The process begins with conducting hydrogel, a water-based polymer with a spongy texture similar to soft contact lenses. "Hydrogel polymers form an interconnected, three-dimensional framework that's ideal for conducting electricity," Bao said. "This framework also contains organic molecules and functional atoms, such as nitrogen, which allow us to tune the electronic properties of the carbon." For the study, the Stanford team used a mild carbonization and activation process to convert the polymer organic frameworks into nanometer-thick sheets of carbon. "The carbon sheets form a 3-D network that has good pore connectivity and high electronic conductivity," said graduate student John To, a co-lead author of the study. "We also added potassium hydroxide to chemically activate the carbon sheets and increase their surface area." The result: designer carbon that can be fine-tuned for a variety of applications. "We call it designer carbon because we can control its chemical composition, pore size and surface area simply by changing the type of polymers and organic linkers we use, or by adjusting the amount of heat we apply during the fabrication process," To said. For example, raising the processing temperature from 750 degrees Fahrenheit (400 degrees Celsius) to 1,650 F (900 C) resulted in a 10-fold increase in pore volume. Subsequent processing produced carbon material with a record-high surface area of 4,073 square meters per gram - the equivalent of three American football fields packed into an ounce of carbon. The maximum surface area achieved with conventional activated carbon is about 3,000 square meters per gram. "High surface area is essential for many applications, including electrocatalysis, storing energy and capturing carbon dioxide emissions from factories and power plants," Bao said. Supercapacitors To see how the new material performed in real-world conditions, the Stanford team fabricated carbon-coated electrodes and installed them in lithium-sulfur batteries and supercapacitors. "Supercapacitors are energy-storage devices widely used in transportation and electronics because of their ultra-fast charging and discharging capability," said postdoctoral scholar Zheng Chen, a co-lead author. "For supercapacitors, the ideal carbon material has a high surface area for storing electrical charges, high conductivity for transporting electrons and a suitable pore architecture that allows for the rapid movement of ions from the electrolyte solution to the carbon surface." In the experiment, a current was applied to supercapacitors equipped with designer-carbon electrodes. The results were dramatic. Electrical conductivity improved threefold compared to supercapacitor electrodes made of conventional activated carbon. "We also found that our designer carbon improved the rate of power delivery and the stability of the electrodes," Bao added. Batteries Tests were also conducted on lithium-sulfur batteries, a promising technology with a serious flaw: When lithium and sulfur react, they produce molecules of lithium polysulfide, which can leak from the electrode into the electrolyte and cause the battery to fail. The Stanford team discovered that electrodes made with designer carbon can trap those pesky polysulfides and improve the battery's performance. "We can easily design electrodes with very small pores that allow lithium ions to diffuse through the carbon but prevent the polysulfides from leaching out," Bao said. "Our designer carbon is simple to make, relatively cheap and meets all of the critical requirements for high-performance electrodes."
read more "New 'designer carbon' boosts battery performance"
A new 'designer carbon' invented by Stanford scientists significantly improved the power delivery rate of this supercapacitor. "We have developed a 'designer carbon' that is both versatile and controllable," said Zhenan Bao, the senior author of the study and a professor of chemical engineering at Stanford. "Our study shows that this material has exceptional energy-storage capacity, enabling unprecedented performance in lithium-sulfur batteries and supercapacitors." According to Bao, the new designer carbon represents a dramatic improvement over conventional activated carbon, an inexpensive material widely used in products ranging from water filters and air deodorizers to energy-storage devices. "A lot of cheap activated carbon is made from coconut shells," Bao said. "To activate the carbon, manufacturers burn the coconut at high temperatures and then chemically treat it." The activation process creates nanosized holes, or pores, that increase the surface area of the carbon, allowing it to catalyze more chemical reactions and store more electrical charges. But activated carbon has serious drawbacks, Bao said. For example, there is little interconnectivity between the pores, which limits their ability to transport electricity. "With activated carbon, there's no way to control pore connectivity," Bao said. "Also, lots of impurities from the coconut shells and other raw starting materials get carried into the carbon. As a refrigerator deodorant, conventional activated carbon is fine, but it doesn't provide high enough performance for electronic devices and energy-storage applications." 3-D networks Instead of using coconut shells, Bao and her colleagues developed a new way to synthesize high-quality carbon using inexpensive - and uncontaminated - chemicals and polymers. The process begins with conducting hydrogel, a water-based polymer with a spongy texture similar to soft contact lenses. "Hydrogel polymers form an interconnected, three-dimensional framework that's ideal for conducting electricity," Bao said. "This framework also contains organic molecules and functional atoms, such as nitrogen, which allow us to tune the electronic properties of the carbon." For the study, the Stanford team used a mild carbonization and activation process to convert the polymer organic frameworks into nanometer-thick sheets of carbon. "The carbon sheets form a 3-D network that has good pore connectivity and high electronic conductivity," said graduate student John To, a co-lead author of the study. "We also added potassium hydroxide to chemically activate the carbon sheets and increase their surface area." The result: designer carbon that can be fine-tuned for a variety of applications. "We call it designer carbon because we can control its chemical composition, pore size and surface area simply by changing the type of polymers and organic linkers we use, or by adjusting the amount of heat we apply during the fabrication process," To said. For example, raising the processing temperature from 750 degrees Fahrenheit (400 degrees Celsius) to 1,650 F (900 C) resulted in a 10-fold increase in pore volume. Subsequent processing produced carbon material with a record-high surface area of 4,073 square meters per gram - the equivalent of three American football fields packed into an ounce of carbon. The maximum surface area achieved with conventional activated carbon is about 3,000 square meters per gram. "High surface area is essential for many applications, including electrocatalysis, storing energy and capturing carbon dioxide emissions from factories and power plants," Bao said. Supercapacitors To see how the new material performed in real-world conditions, the Stanford team fabricated carbon-coated electrodes and installed them in lithium-sulfur batteries and supercapacitors. "Supercapacitors are energy-storage devices widely used in transportation and electronics because of their ultra-fast charging and discharging capability," said postdoctoral scholar Zheng Chen, a co-lead author. "For supercapacitors, the ideal carbon material has a high surface area for storing electrical charges, high conductivity for transporting electrons and a suitable pore architecture that allows for the rapid movement of ions from the electrolyte solution to the carbon surface." In the experiment, a current was applied to supercapacitors equipped with designer-carbon electrodes. The results were dramatic. Electrical conductivity improved threefold compared to supercapacitor electrodes made of conventional activated carbon. "We also found that our designer carbon improved the rate of power delivery and the stability of the electrodes," Bao added. Batteries Tests were also conducted on lithium-sulfur batteries, a promising technology with a serious flaw: When lithium and sulfur react, they produce molecules of lithium polysulfide, which can leak from the electrode into the electrolyte and cause the battery to fail. The Stanford team discovered that electrodes made with designer carbon can trap those pesky polysulfides and improve the battery's performance. "We can easily design electrodes with very small pores that allow lithium ions to diffuse through the carbon but prevent the polysulfides from leaching out," Bao said. "Our designer carbon is simple to make, relatively cheap and meets all of the critical requirements for high-performance electrodes."
Magnetoresistance measurements indicate the presence of electron pairs at the interface between zinc oxide and magnesium zinc oxide. (Image: Joseph Falson, University of Tokyo) Applying an electric potential between the two sides of a two-dimensional sheet of a semiconducting material under a magnetic field can cause charge carriers to flow sideways along the sheet. This is known as the Hall effect, and such materials display electrical resistance both in the direction of the applied voltage and perpendicular to it. The quantum Hall effect, a signature of two-dimensional systems, becomes evident when the magnetic field is increased and the perpendicular Hall resistance increases in discrete steps. Each of these steps corresponds to an electrical conductance equal to a fundamental constant multiplied by a fraction in which both the numerator and denominator are integers. A team of researchers from the RIKEN Center for Emergent Matter Science, University of Tokyo, the Max Planck Institute for Solid State Research in Germany and other Japanese institutions has now observed the fractional quantum Hall effect in a two-dimensional system formed at the interface between zinc oxide and magnesium zinc oxide. Fundamental to the team’s success in observing such an exotic quantum effect was the fabrication of high-quality material systems. The researchers created their ZnO-based structure using a method called molecular beam epitaxy, which is known for its ability to produce materials with high crystalline quality. They then attached eight electrical contacts to their sample and performed magnetoresistance measurements at ultralow temperatures. The researchers observed a series of levels corresponding to fractional states, or filling factors, between 4/3 and 9/2. Most notably, even-denominator states were observed at 3/2 and 7/2, with some evidence for 9/2. Such a series has not been observed in any other material system. These states are believed to arise because of the existence of quasiparticles made of pairs of electrons (Fig. 1). Such particle pairs are expected to be useful in quantum computers. “These quasiparticles are said to be topologically protected and are robust against weak perturbations,” says the study’s lead author Joseph Falson. “This is in contrast to quantum bits in say, silicon, which are very sensitive to slight changes in temperature or electric field. We now plan to probe the details of the states this work has unveiled.”
An illustration of atoms sticking to a carbon nanotube, affecting the electrons in its surface. (Image: David Cobden and students) Cobden said he and co-authors found that when an atom or molecule sticks to the nanotube a tiny fraction of the charge of one electron is transferred to its surface, resulting in a measurable change in electrical resistance. “This aspect of atoms interacting with surfaces has never been detected unambiguously before,” Cobden said. “When many atoms are stuck to the miniscule tube at the same time, the measurements reveal their collective dances, including big fluctuations that occur on warming analogous to the boiling of water.” Lithium batteries involve lithium atoms sticking and transferring charges to carbon electrodes, and in activated charcoal filters, molecules stick to the carbon surface to be removed, Cobden explained. “Various forms of carbon, including nanotubes, are considered for hydrogen or other fuel storage because they have a huge internal surface area for the fuel molecules to stick to. However, these technological situations are extremely complex and difficult to do precise, clear-cut measurements on.” This work, he said, resulted in the most precise and controlled measurements of these interactions ever made, “and will allow scientists to learn new things about the interplay of atoms and molecules with a carbon surface,” important for improving technologies including batteries, electrodes and air filters.
Infrared light enters this silicon structure from the left. The cut-out patterns, determined by an algorithm, route two different frequencies of this light into the pathways on the right. This is a greatly magnified image of a working device that is about the size of a speck of dust. (Image: Alexander Piggott) Proven technology In essence, the Stanford engineers want to miniaturize the proven technology of the Internet, which moves data by beaming photons of light through fiber optic threads. "Optical transport uses far less energy than sending electrons through wires," Piggott said. "For chip-scale links, light can carry more than 20 times as much data." Theoretically, this is doable because silicon is transparent to infrared light - the way glass is transparent to visible light. So wires could be replaced by optical interconnects: silicon structures designed to carry infrared light. But so far, engineers have had to design optical interconnects one at a time. Given that thousands of such linkages are needed for each electronic system, optical data transport has remained impractical. Now the Stanford engineers believe they've broken that bottleneck by inventing what they call an inverse design algorithm. It works as the name suggests: the engineers specify what they want the optical circuit to do, and the software provides the details of how to fabricate a silicon structure to perform the task. "We used the algorithm to design a working optical circuit and made several copies in our lab," Vuckovic said. In addition to Piggott, the research team included former graduate student Jesse Lu (now at Google,) graduate student Jan Petykiewicz and postdoctoral scholars Thomas Babinec and Konstantinos Lagoudakis. As they reported in Nature Photonics, the devices functioned flawlessly despite tiny imperfections. "Our manufacturing processes are not nearly as precise as those at commercial fabrication plants," Piggott said. "The fact that we could build devices this robust on our equipment tells us that this technology will be easy to mass-produce at state-of-the-art facilities." The researchers envision many other potential applications for their inverse design algorithm, including high bandwidth optical communications, compact microscopy systems and ultra-secure quantum communications. Light and silicon The Stanford work relies on the well-known fact that infrared light will pass through silicon the way sunlight shines through glass. And just as a prism bends visible light to reveal the rainbow, different silicon structures can bend infrared light in useful ways. The Stanford algorithm designs silicon structures so slender that more than 20 of them could sit side-by-side inside the diameter of a human hair. These silicon interconnects can direct a specific frequency of infrared light to a specific location to replace a wire. By loading data onto these frequencies, the Stanford algorithm can create switches or conduits or whatever else is required for the task. The inverse design algorithm is what makes optical interconnects practical by describing how to create what amount to silicon prisms to bend infrared light. Once the algorithm has calculated the proper shape for the task, engineers can use standard industrial processes to transfer that pattern onto a slice of silicon. "Our structures look like Swiss cheese but they work better than anything we've seen before," Vuckovic said. She and Piggott have made several different types of optical interconnects and they see no limits on what their inverse design algorithm can do. In their Nature photonics paper, the Stanford authors note that the automation of large-scale circuit design enabled engineers to create today's sophisticated electronics. By automating the process of designing optical interconnects, they feel that they have set the stage for the next generation of even faster and far more energy-efficient computers that use light rather than electricity for internal data transport.
Chemists at the University of Waterloo have discovered the key reaction that takes place in sodium-air batteries that could pave the way for development of the so-called holy grail of electrochemical energy storage. The key lies in Nazar's group discovery of the so-called proton phase transfer catalyst. By isolating its role in the battery's discharge and recharge reactions, Nazar and colleagues were not only able to boost the battery's capacity, they achieved a near-perfect recharge of the cell. When the researchers eliminated the catalyst from the system, they found the battery no longer worked. Unlike the traditional solid-state battery design, a metal-oxygen battery uses a gas cathode that takes oxygen and combines it with a metal such as sodium or lithium to form a metal oxide, storing electrons in the process. Applying an electric current reverses the reaction and reverts the metal to its original form. (Image: University of Waterloo) "Our new understanding brings together a lot of different, disconnected bits of a puzzle that have allowed us to assemble the full picture," says Nazar, a Chemistry professor in the Faculty of Science. "These findings will change the way we think about non-aqueous metal-oxygen batteries." Sodium-oxygen batteries are considered by many to be a particularly promising metal-oxygen battery combination. Although less energy dense than lithium-oxygen cells, they can be recharged with more than 93 per cent efficiency and are cheap enough for large-scale electrical grid storage. The key lies in Nazar's group discovery of the so-called proton phase transfer catalyst. By isolating its role in the battery's discharge and recharge reactions, Nazar and colleagues were not only able to boost the battery's capacity, they achieved a near-perfect recharge of the cell. When the researchers eliminated the catalyst from the system, they found the battery no longer worked. Unlike the traditional solid-state battery design, a metal-oxygen battery uses a gas cathode that takes oxygen and combines it with a metal such as sodium or lithium to form a metal oxide, storing electrons in the process. Applying an electric current reverses the reaction and reverts the metal to its original form. In the case of the sodium-oxygen cell, the proton phase catalyst transfers the newly formed sodium superoxide (NaO
This is the tetragonal crystal structure of NaFe
Alexander Szameit and his team of the University Jena developed a photonic set-up that can simulate non-physical processes in a laboratory. March 1938: The Italian elementary particle physicist Ettore Majorana boarded a post ship in Naples, heading for Palermo. But he either never arrives there - or he leaves the city straight away – ever since that day there has been no trace of the exceptional scientist and until today his mysterious disappearance remains unresolved. Since then, Majorana, a pupil of the Nobel Prize winner Enrico Fermi, has more or less been forgotten. What the scientific world does remember though is a theory about nuclear forces, which he developed, and a very particular elementary particle. “This particle named after Majorana, the so-called Majoranon, has some amazing characteristics“, the physicist Professor Dr. Alexander Szameit of the Friedrich Schiller University Jena says. “Characteristics which are not supposed to be existent in our real world.“ Majorana particles are, for instance, their own antiparticles: Internally they combine completely opposing characteristics – like opposing charges and spins. If they were to exist, they would extinguish themselves immediately. “Therefore, Majoranons are of an entirely theoretical nature and cannot be measured in experiments.“ Together with colleagues from Austria, India, and Singapore, Alexander Szameit and his team succeeded in realizing the impossible. In the new edition of the science magazine they explain their approach: Szameit and his team developed a photonic set-up that consists of complex waveguide circuits engraved in a glass chip, which enables them to simulate charged Majorana particles and, thus, allows to conduct physical experiments. “At the same time we send two rays of light through parallel running waveguide lattices, which show the opposing characteristics separately,“ explains Dr. Robert Keil, the first author of the study. After evolution through the lattices, the two waves interfere and form an optical Majoranon, which can be measured as a light distribution. Thus, the scientists create an image that catches this effect like a photograph – in this case the state of a Majoranon at a defined moment in time. “With the help of many of such single images the particles can be observed like in a film and their behaviour can be analyzed,“ says Keil. This model allows the Jena scientists to enter completely unknown scientific territory, as Alexander Szameit stresses. “Now, it is possible for us to gain access to phenomena that so far only have been described in exotic theories.“ With the help of this system, one can conduct experiments in which conservation of charge – one of the pillars of modern physics – can easily be suspended. “Our results show that one can simulate non-physical processes in a laboratory and, thus, can make practical use of exotic characteristics of particles that are impossible to observe in nature.“ Szameit foresees one particular promising application of simulated Majoranons in a new generation of quantum computers. “With this approach, much higher computing capacities than are possible at the moment can be achieved.“
An artist's concept of cell hemifusion. (Illustration by Peter Allen) 'It is hard to simultaneously image hemifusion and measure membrane thickness and interaction forces due to the technical limitations,' he said. However, by combining the capabilities of the Surface Forces Apparatus (SFA) -- a device that can measure the tiny forces generated by the interaction of two surfaces at the sub-nano scale -- and simultaneous imaging using a fluorescence microscope, the researchers were able to see in real time how the cell membranes rearrange in order to connect and open a fusion conduit between them. The SFA was developed in Professor Jacob Israelachvili's Interfacial Sciences Lab at UCSB. Israelachvili is a faculty member in the Department of Chemical Engineering at UCSB. To capture real time data on the behavior of cell membranes during hemifusion, the researchers pressed together two supported lipid bilayers on the opposing surfaces of the SFA. These bilayers consisted of lipid domains -- collections of lipids that in non-fusion circumstances are organized in more or less regularly occurring or mixed arrangements within the cell membrane. 'We monitored these lipid domains to see how they reorganize and relocate during hemifusion,' said Lee. The SFA measured the forces and distances between the two membrane surfaces as they were pushed together, visualized at the Ångstrom (one-tenth of a nanometer) level. Meanwhile, fluorescent imaging made it possible to see the action as the more ordered-phase (more solid) domains reorganized and allowed the more disordered-phase (more fluid) domains to concentrate at the point of contact. 'This is the first time observing fluorescent images during a hemifusion process simultaneously with how the combined thickness of the two bilayers evolve to form a single layer,' said Lee. This rearrangement of the domains, he added, lowers the amount of energy needed during the many processes that require membrane fusion. At higher pressures, according to the study, the extra energy activates faster hemifusion of the lipid layers. Lipid domains have been seen in many biological cell membranes, and have been linked to various diseases such as multiple sclerosis, Alzheimer's disease and lung diseases. According to the researchers, this novel device could be used to diagnose, provide a marker for, or study dynamic transformations in situations involving lipid domains in pathological membranes. The fundamental insights provided by this device could also prove useful for other materials in which dynamic changes occur between membranes, including surfactant monolayers and bilayers, biomolecules, colloidal particles, surfactant-coated nanoparticles and smart materials.
Polymeric nanoimaging agents carrying attached MRI tracer are able to pass through the blood–brain barrier (BBB) and specifically target cancer cells for efficient imaging. A qualitative/quantitative “MRI virtual biopsy” method is based on a nanoconjugate carrying MRI contrast agent gadolinium-DOTA and antibodies recognizing tumor-specific markers and extravasating through the BBB. In newly developed double tumor xenogeneic mouse models of brain metastasis this noninvasive method allowed differential diagnosis of HER2- and EGFR-expressing brain tumors. (© ACS) Ljubimova, director of the Nanomedicine Research Center in the Department of Neurosurgery and director of the Nanomedicine Program at the Samuel Oschin Comprehensive Cancer Institute, has received a $2.5 million grant from the National Institutes of Health to continue the research. The drug delivery system and its component parts, together called a nanobioconjugate or nanodrug, is in an emerging class of molecular drugs designed to slow or stop cancers by blocking them in multiple ways within the brain. The drug is about 20 to 30 nanometers in size – a fraction of a human hair, which is 80,000 to 100,000 nanometers wide. Cedars-Sinai scientists began developing the “platform” of the drug delivery system about a decade ago. The nanodrug can have a variety of chemical and biological “modules” attached. “Each component serves a specialized function, such as seeking out cancer cells and binding to them, permeating the walls of blood vessels and tumor cells, or dismantling molecular mechanisms that promote tumor growth,” said Eggehard Holler, PhD, professor of neurosurgery and director of nanodrug synthesis at Cedars-Sinai. The new delivery system plays two roles: diagnosing brain tumors by identifying cells that have spread to the brain from other organs, and then fighting the cancer with precise, individualized tumor treatment. Researchers can determine tumor type by attaching a tracer visible on an MRI. If the tracer accumulates in the tumor, it will be visible on MRI. With the cancer’s molecular makeup identified through this virtual biopsy, researches can load the “delivery system” with cancer-targeting components that specifically attack the molecular structure. To show that the virtual biopsies could distinguish one cancer cell type from another, the researchers devised what is believed to be a unique method, implanting different kinds of breast and lung cancers into laboratory mice to represent metastatic disease – with one type of cancer implanted on each side of the brain. Lung and breast cancers are those that most often spread to the brain. The researchers used the nano delivery system to identify and attack the cancers. In each instance, animals that received treatment lived significantly longer than those in control groups. “Several drugs are quite effective in treating different types of breast cancers, lung cancer, lymphoma and other cancers at their original sites, but they are ineffective against cancers that spread to the brain because they are not able to cross the blood-brain barrier that protects the brain from toxins in the blood,” said Keith Black, MD, chair of the Department of Neurosurgery, director of the Maxine Dunitz Neurosurgical Institute, director of the Johnnie L. Cochran, Jr., Brain Tumor Center and the Ruth and Lawrence Harvey Chair in Neuroscience. “The nanodrug is engineered to cross this barrier with its payload intact, so drugs that are effective outside the brain may be effective inside as well,” Black added. Ljubimova, Black and Holler led the study and contributed equally to the article. Rameshwar Patil, PhD, a project scientist in Ljubimova’s laboratory, is first author. Researchers from Cedars-Sinai’s Department of Neurosurgery, Department of Biomedical Sciences, Department of Imaging, and the Samuel Oschin Comprehensive Cancer Institute contributed to the study with colleagues from the University of Southern California and Arrogene Inc., a biotech company associated with Cedars-Sinai.
Zhigang Gui (left), Laurent Bellaiche Gui used supercomputers at Oak Ridge National Laboratory to perform large-scale computations to determine the electrical properties of electrical vortices in ferroelectric materials, which generate an electric field when their shape is changed. An electrical vortex occurs when the electric dipoles arrange themselves in an unusual swirling movement, Bellaiche said. In this ferroelectric system, electrical vortices are created and determined by the temperature of the material, Bellaiche said. The simulations also revealed that the existence of an electrical vortex increases the band gap – the major factor determining a material’s conductivity – in this material, which offers insight to the controversial issue about the origin of the conductivity of electrical vortices. “By changing temperature we are changing the band alignment,” Gui said. “Imagine having the same system having two different band alignments, which can lead to different applications. When decreasing temperature, our systems can transform from a Type-I band alignment, which favors light-emitting devices, to a Type-II band alignment, which favors sensors in semiconductor industries.”
Scientists built octahedrons using ropelike structures made of bundles of DNA double-helix molecules to form the frames (a). Single strands of DNA attached at the vertices (numbered in red) can be used to attach nanoparticles coated with complementary strands. This approach can yield a variety of structures, including ones with the same type of particle at each vertex (b), arrangements with particles placed only on certain vertices (c), and structures with different particles placed strategically on different vertices (d). "These arrays of nanoparticles with predictable geometric configurations are somewhat analogous to molecules made of atoms," said Brookhaven physicist Oleg Gang, who led the project at the Lab's Center for Functional Nanomaterials (CFN, http://www.bnl.gov/cfn/), a DOE Office of Science User Facility. "While atoms form molecules based on the nature of their chemical bonds, there has been no easy way to impose such a specific spatial binding scheme on nanoparticles. This is exactly the problem that our method addresses." Using the new method, the scientists say they can potentially orchestrate the arrangements of different types of nanoparticles to take advantage of collective or synergistic effects. Examples could include materials that regulate energy flow, rotate light, or deliver biomolecules. "We may be able to design materials that mimic nature's machinery to harvest solar energy, or manipulate light for telecommunications applications, or design novel catalysts for speeding up a variety of chemical reactions," Gang said. The scientists demonstrated the technique to engineer nanoparticle architectures using an octahedral scaffold with particles positioned in precise locations on the scaffold according to the specificity of DNA coding. The designs included two different arrangements of the same set of particles, where each configuration had different optical characteristics. They also used the geometrical clusters as building blocks for larger arrays, including linear chains and two-dimensional planar sheets. "Our work demonstrates the versatility of this approach and opens up numerous exciting opportunities for high-yield precision assembly of tailored 3D building blocks in which multiple nanoparticles of different structures and functions can be integrated," said CFN scientist Ye Tian, one of the lead authors on the paper. 
A combination cryo-electron microscopy image of an octahedral frame with one gold nanoparticle bound to each of the six vertices, shown from three different angles. Details of assembly This nanoscale construction approach takes advantage of two key characteristics of the DNA molecule: the twisted-ladder double helix shape, and the natural tendency of strands with complementary bases (the A, T, G, and C letters of the genetic code) to pair up in a precise way. First, the scientists created bundles of six double-helix molecules, then put four of these bundles together to make a stable, somewhat rigid building material--similar to the way individual fibrous strands are woven together to make a very strong rope. The scientists then used these ropelike girders to form the frame of three-dimensional octahedrons, "stapling" the linear DNA chains together with hundreds of short complementary DNA strands. "We refer to these as DNA origami octahedrons," Gang said. To make it possible to "glue" nanoparticles to the 3D frames, the scientists engineered each of the original six-helix bundles to have one helix with an extra single-stranded piece of DNA sticking out from both ends. When assembled into the 3D octahedrons, each vertex of the frame had a few of these "sticky end" tethers available for binding with objects coated with complementary DNA strands. "When nanoparticles coated with single strand tethers are mixed with the DNA origami octahedrons, the 'free' pieces of DNA find one another so the bases can pair up according to the rules of the DNA complementarity code. Thus the specifically DNA-encoded particles can find their correspondingly designed place on the octahedron vertices" Gang said. The scientists can change what binds to each vertex by changing the DNA sequences encoded on the tethers. In one experiment, they encoded the same sequence on all the octahedron's tethers, and attached strands with a complementary sequence to gold nanoparticles. The result: One gold nanoparticle attached to each of octahedron's six vertices. In additional experiments the scientists changed the sequence of some vertices and used complementary strands on different kinds of particles, illustrating that they could direct the assembly and arrangement of the particles in a very precise way. In one case they made two different arrangements of the same three pairs of particles of different sizes, producing products with different optical properties. They were even able to use DNA tethers on selected vertices to link octahedrons end to end, forming chains, and in 2D arrays, forming sheets. 
By strategically placing tethers on particular vertices, the scientists used the octahedrons to link nanoparticles into one-dimensional chainlike arrays (left) and two-dimensional square sheets (right). Visualization of arrays Confirming the particle arrangements and structures was a major challenge because the nanoparticles and the DNA molecules making up the frames have very different densities. Certain microscopy techniques would reveal only the particles, while others would distort the 3D structures. To see both the particles and origami frames, the scientists used cryo-electron microscopy (cryo-EM), led by Brookhaven Lab and Stony Brook University biologist Huilin Li, an expert in this technique, and Tong Wang, the paper's other lead co-author, who works in Brookhaven's Biosciences department with Li. They had to subtract information from the images to "see" the different density components separately, then combine the information using single particle 3D reconstruction and tomography to produce the final images. "Cryo-EM preserves samples in their near-native states and provides close to nanometer resolution," Wang said. "We show that cryo-EM can be successfully applied to probe the 3D structure of DNA-nanoparticle clusters." These images confirm that this approach to direct the placement of nanoparticles on DNA-encoded vertices of molecular frames could be a successful strategy for fabricating novel nanomaterials.
Introducing "reprogramming" DNA strands into an already assembled nanoparticle array triggers a transition from a "mother phase," where particles occupy the corners and center of a cube (left), to a more compact "daughter phase" (right). The change represented in the schematic diagrams is revealed by the associated small-angle x-ray scattering patterns. Such phase-changes could potentially be used to switch a material's properties on demand. "One of the goals in nanoparticle self-assembly has been to create structures by design," said Oleg Gang, who led the work at Brookhaven's Center for Functional Nanomaterials, a DOE Office of Science User Facility. "Until now, most of the structures we've built have been static. Now we are trying to achieve an even more ambitious goal: making materials that can transform so we can take advantage of properties that emerge with the particles' rearrangements." The ability to direct particle rearrangements, or phase changes, will allow the scientists to choose the desired properties-say, the material's response to light or a magnetic field-and switch them as needed. Such phase-changing materials could lead to new applications, such as dynamic energy-harvesting or responsive optical materials. DNA-directed rearrangement This latest advance in nanoscale engineering builds on the team's previous work developing ways to get nanoparticles to self-assemble into complex composite arrays, including linking them together with tethers constructed of complementary strands of synthetic DNA. In this case, they started with an assembly of nanoparticles already linked in a regular array by the complementary binding of the A, T, G, and C bases on single stranded DNA tethers, then added "reprogramming" DNA strands to alter the interparticle interactions. "We know that properties of materials built from nanoparticles are strongly dependent on their arrangements," said Gang. "Previously, we've even been able to manipulate optical properties by shortening or lengthening the DNA tethers. But that approach does not permit us to achieve a global reorganization of the entire structure once it's already built." In the new approach, the reprogramming DNA strands adhere to open binding sites on the already assembled nanoparticles. These strands exert additional forces on the linked-up nanoparticles. 
Injecting different kinds of reprogramming DNA strands can change the interparticle interactions in different ways depending on whether the new strands increase attraction, repulsion, or a combination of these forces between particles. "By introducing different types of reprogramming DNA strands, we modify the DNA shells surrounding the nanoparticles," explained CFN postdoctoral fellow Yugang Zhang, the lead author on the paper. "Altering these shells can selectively shift the particle-particle interactions, either by increasing both attraction and repulsion, or by separately increasing only attraction or only repulsion. These reprogrammed interactions impose new constraints on the particles, forcing them to achieve a new structural organization to satisfy those constraints." Using their method, the team demonstrated that they could switch their original nanoparticle array, the "mother" phase, into multiple different daughter phases with precision control. This is quite different from phase changes driven by external physical conditions such as pressure or temperature, Gang said, which typically result in single phase shifts, or sometimes sequential ones. "In those cases, to go from phase A to phase C, you first have to shift from A to B and then B to C," said Gang. "Our method allows us to pick which daughter phase we want and go right to that one because the daughter phase is completely determined by the type of DNA reprogramming strands we use." 
Various types of reprogramming strands can be used to selectively trigger the transformation to different phases, or configurations, of the same particle combinations. The scientists were able to observe the structural transformations to various daughter phases using a technique called in situ small-angle x-ray scattering at the National Synchrotron Light Source (http://www.bnl.gov/ps/), another DOE Office of Science User Facility that operated at Brookhaven Lab from 1982 until last September (now replaced by NSLS-II, which produces x-ray beams 10,000 times brighter). The team also used computational modeling to calculate how different kinds of reprogramming strands would alter the interparticle interactions, and found their calculations agreed well with their experimental observations. "The ability to dynamically switch the phase of an entire superlattice array will allow the creation of reprogrammable and switchable materials wherein multiple, different functions can be activated on demand," said Gang. "Our experimental work and accompanying theoretical analysis confirm that reprogramming DNA-mediated interactions among nanoparticles is a viable way to achieve this goal."
The researchers from the Centre for Quantum and Optical Science used their table-top laser setup to illuminate a gas cell of argon with two intense beams of ultrashort laser pulses at different wavelengths. One beam generates ‘high-order harmonics’ in the extreme UV, while the effect of the second overlapping beam is to amplify the extreme UV radiation by a process known as optical parametric amplification. These bright coherent beams of extreme UV radiation will be used for high resolution imaging based on a ‘lensless’ imaging technique called coherent diffractive imaging, in which images are reconstructed by a computer. “This research paves the way for the generation of intense radiation at still shorter wavelengths and ultimately to apply coherent diffractive imaging techniques to nano-scale structures and to biological samples in the water window region (2-4 nanometres),” Emeritus Professor Peter Hannaford said. The new research has been published in the prestigious journal ("Perturbative optical parametric amplification in the extreme ultraviolet").
Tribologist Brandon A. Krick and graduate student Mark Sidebottom will lead experimental efforts. (Image: Lehigh University) Professor Krick is partnering with colleagues from DuPont on a project that's recently won a "GOALI" grant from the National Science Foundation (NSF). The intent is to expand the Lehigh Tribology Lab's fight against friction, its war on wear. A 2013 addition to the mechanical engineering faculty at Lehigh University, Krick studies the fundamental origins of friction, wear, materials deformation, and adhesion on complex surfaces ranging from cells to nanocomposites, in environments ranging from space to thousands of feet under water. Netting a GOALI The NSF's Grant Opportunities for Academic Liaison with Industry (GOALI) program promotes university-industry partnerships by making project funds or fellowships/traineeships available to support an eclectic mix of industry-university linkages. According to the NSF Web site, special consideration is provided to interdisciplinary projects that create opportunities for faculty, postdoctoral researchers, and students to conduct research and gain experience in an industrial setting, while enabling industrial scientists and engineers to bring their perspective and skills to academia. Professor Krick says that the Lehigh-DuPont team will develop and study ultralow-wear composite materials suitable for manufacturability and usage in commercial and industrial settings. Krick will serve as principal investigator on the project, with DuPont scientists Christopher Junk and Gregory Blackman serving as co-principal investigators and Lehigh graduate student Mark Sidebottom leading the experimental efforts. "We'll be exploring how various material structures, composition, processing and operating conditions impact tribological performance," Krick reports. "We'll also gain a much more complete understanding of the mechanical and chemical processes involved in wearing down materials we're developing." "Working on this NSF GOALI proposal has been a truly collaborative, multidisciplinary process that could not have been completed without the help of our talented team members," say DuPont collaborators Junk and Blackman. "This project will focus on very fundamental questions, but with real applications in mind. Being on this team with Professor Krick has made us all better scientists and engineers, and we are eager to continue to build our partnership and help train new researchers along the way." According to the grant materials, "the research will use student-built instruments to directly validate the hypothesized mechanism that in situ tribochemical reaction products alter the properties of otherwise inert fluoropolymers. A multi-faceted characterization approach will systematically test the hypotheses and discover new mechanisms of these materials that could, ultimately, enable science-based design of new materials that are incredibly resistant to wear." The grant also calls for the development of outreach programs and educational opportunities in the field of tribology. Krick and his colleagues at DuPont have been partners fighting wear for several years. DuPont supported much of Krick's work as a student and researcher at the University of Florida, and the relationship has carried over into his activities at Lehigh. "DuPont is one of the world's premier industrial scientific communities," says Krick. "Working with the DuPont team has been one of the most productive and rewarding collaborations of my life." Krick was attracted to Lehigh due to its intense focus on interdisciplinary education and research and the power of its material characterization facility - the Center for Advanced Materials and Nanotechnology. "I'm in this field that relies heavily on collaboration, and I saw a lot of talented students and faculty here, and research capabilities that are right in my wheelhouse - the right place to build a research program," he says. Krick feels that the study of tribology gets far less credit than it deserves. "Lately there has been a large push for green manufacturing, new sources of energy, ways to make things more efficient. With tribology, we can make machines work more efficiently, significantly improving energy and material usage. If we can reduce the energy demands of machines and devices, we make use of alternative energy sources much more feasible."
High-energy gold ions impact the crystal surface from above at the sites indicated schematically by dashed circles. Measurement of the strength of superconductivity in this same field of view, as shown on the lower panel, reveals how the impact sites are the regions where the superconductivity is also annihilated. In additional studies, the scientists discovered that it is in these same regions that the strongest pinning of quantized vortices occurs, followed at higher magnetic fields by pinning at the single atom crystal damage sites. Pinning the vortices allows high current superconductivity to flow unimpeded through the rest of the sample. (Image: Brookhaven National Laboratory) The work is a product of the Center for Emergent Superconductivity, a DOE Energy Frontier Research Center established at Brookhaven in partnership with Argonne and the University of Illinois to foster collaboration and maximize the impact of this research. "This study opens a new way forward for designing and understanding high-current, high-performing superconductors," said study co-author J.C. Séamus Davis, a physicist at Brookhaven Lab and Cornell University. "We demonstrated a procedure whereby you can irradiate a sample with heavy ions, visualize what the ions do to the crystal at the atomic scale, and simultaneously see what happens to the superconductivity in precisely the same field of view." Argonne physicist Wai-Kwong Kwok led the effort on heavy ion bombardment. "Heavy ions such as gold can create nearly continuous or discontinuous column shaped damage tracks penetrating through the crystal. As the very high-energy ions traverse the material, they melt the crystal at the atomic scale and destroy the crystal structure over a diameter of a few nanometers. It's important to understand the details of how these atomic-scale defects affect local electronic properties and the macroscopic current carrying capacity of the bulk material," he said. The scientists were particularly interested in how the nanoscale defects interact with microscopic magnetic vortices that form when iron-based superconductors are placed in a strong magnetic field -- the type that would be present in turbines and other energy applications. "These quantum vortices are like eddies in a river moving across or counter to the direction of flow," Davis said. "They are the enemy of superconductivity. You can't prevent them from forming, but scientists as long ago as the 1970s found you can sometimes prevent them from moving around by shooting some high-energy ions into the material to form atomic-scale damage tracks that trap the vortices." But random bombardment is, literally, hit-or-miss. Scientists developing materials for energy applications would like to take a more strategic approach by developing a quantitative and predictive theory for how to engineer these materials. "If a company comes to us and says we are developing these superconductors and we want them to have this current at a certain temperature in this type of magnetic field, we'd like to be able to tell them exactly what type of defects to introduce," Kwok said. To do that they needed a way to map out the defects, map out the superconductivity, and map out the locations of the vortices -- and a quantitative theoretical model that describes how those variables relate to one another and the material's bulk superconductivity. A precision spectroscopic-imaging scanning tunneling microscope (SI-STM) developed by Davis is the first tool that can map out those three characteristics on the same material. Under Davis' guidance, Brookhaven Lab postdoctoral fellow Freek Massee (now at University Paris-Sud in France) and Cornell University graduate student Peter Sprau -- the two lead co-authors on the paper -- used the instrument's fine electron-tunneling tip to scan over the material's surface, imaging the atomic structure of the landscape below and the properties of its electrons, atom by atom. The precision allows the scientists to scan the same atoms repeatedly under different external conditions -- such as changes in temperature and ramped up magnetic fields -- to study the formation, movement, and effects of quantum vortices. Their atomic-scale imaging studies reveal that vortex pinning -- the ability to keep those disruptive eddies in place -- depends on the shape of the high-energy ion damage tracks (specifically whether they are point-like or elongated), and also on a form of "collateral damage" discovered by the researchers far from the primary route traversed by each ion. Collaborating theorists at the University of Illinois are now using the experimental results to develop a descriptive framework the scientists can use to predict and test new approaches for materials design. "These studies will really help us solve at which temperature which type of defects will be best for carrying a particular current," Kwok said. "The ability to achieve critical current by design is one of the ultimate goals of the Center for Emergent Superconductivity."
Schematic of the ionic polymer-graphene composite (IPGC) actuator or “motor”. When an electric field is applied, the redistribution of ions causes the structure to bend. (Image: Korea Advanced Institute of Science and Technology) In a paper published in ("Durable and Water-Floatable Ionic Polymer Actuator with Hydrophobic and Asymmetrically Laser-Scribed Reduced Graphene Oxide Paper Electrodes"), researchers from the Korea Advanced Institute of Science and Technology report the development of a thin-film electrode based on a novel ionic polymer-graphene composite (IPGC). Graphene is a single-atom-thick layer of carbon with exceptional mechanical, electrical and thermal properties. The new electrodes have a smooth outer surface that repels water and doesn’t have apparent cracks, which makes them nearly impermeable to liquids. They also have a rough inner surface, which facilitates the migration of ions within the membrane to stimulate bending. The new IPGC actuator demonstrates exceptional durability without apparent degradation, even under very high input voltage. It shows promise for use in biomedical devices, “biomimetic” robots that mimic movements occurring in nature, and flexible soft electronics. The researchers acknowledge that there are still many challenges and more research is needed to realise the full potential of the graphene-based electrodes and their subsequent commercialisation. In 2015, they plan to further enhance the bending performance of the actuators, their ability to store energy and their power. They also plan to develop a biomimetic robot that can walk and jump on water like a water strider. They will do this by constructing floatable IPGC actuators with a reliable bending performance that can continue for a period of six hours without any apparent change in durability.
A device is remotely triggered to self-destruct. A radio-frequency signal turns on a heating element at the center of the device. The circuits dissolve completely. (Image: Scott White, University of Illinois) "We have demonstrated electronics that are there when you need them and gone when you don't need them anymore," White said. "This is a way of creating sustainability in the materials that are used in modern-day electronics. This was our first attempt to use an environmental stimulus to trigger destruction." White's group teamed up with John A. Rogers, a Swanlund chair in materials science and engineering and director of the Frederick Seitz Materials Laboratory at Illinois. Rogers' group pioneered transient devices that dissolve in water, with applications for biomedical implants. Together, the two multi-disciplinary research groups have tackled the problem of using other triggers to break down devices, including ultraviolet light, heat and mechanical stress. The goal is to find ways to disintegrate the devices so that manufacturers can recycle costly materials from used or obsolete devices or so that the devices could break down in a landfill. The heat-triggered devices use magnesium circuits printed on very thin, flexible materials. The researchers trap microscopic droplets of a weak acid in wax, and coat the devices with the wax. When the devices are heated, the wax melts, releasing the acid. The acid dissolves the device quickly and completely. To remotely trigger the reaction, researchers embedded a radio-frequency receiver and an inductive heating coil in the device. The user can send a signal to cause the coil to heat up, which melts the wax and dissolves the device. Watch a video of the researchers demonstrating and explaining the devices:
]]> http://bit.ly/1K2oLEi Mon, 11 May 2015 12:37:11 -0400 http://bit.ly/1K2oLEj Researchers produced biocompatible and biodegradable non-ionic polymeric nanocarriers that can be used in the targeted anticancer drug delivery. ]]> http://bit.ly/1K2oLEj Sat, 09 May 2015 04:24:55 -0400 http://bit.ly/1K2oNfw Precise control of interactions between light and vibrating mirrors at the level of single light particles could open a new field of complex quantum physical states. 
]]> http://bit.ly/1K2oNfw Fri, 08 May 2015 04:09:31 -0400 http://bit.ly/1K2oLEn By speeding up a real atomic force microscope and slowing down a simulation of one, researchers have conducted the first atomic-scale experiments on friction at overlapping speeds. 
]]> http://bit.ly/1K2oLEn Fri, 08 May 2015 04:16:39 -0400 http://bit.ly/1K2oNvR Scientists have not only uncovered the quantitative secret to understanding friction in materials, like graphite, they even invented a way to measure it. 
]]> http://bit.ly/1K2oNvR Fri, 08 May 2015 04:25:22 -0400 http://bit.ly/1HafTsy A convenient procedure to visualize defects on graphene layers by mapping the surface of carbon materials with an appropriate contrast agent. 
]]> http://bit.ly/1HafTsy Fri, 08 May 2015 09:07:07 -0400 http://bit.ly/1K2oNvS Plant-based cellulose nanofibres do not pose a short-term health risk, especially short fibres, shows a new study. ]]> http://bit.ly/1K2oNvS Thu, 07 May 2015 14:32:51 -0400 http://bit.ly/1K2oNvT Researchers have discovered a novel way of combining plasmonic and magneto-optical effects. They experimentally demonstrated that patterning of magnetic materials into arrays of nanoscale dots can lead to a very strong and highly controllable modification of the polarization of light when the beam reflects from the array. 
]]> http://bit.ly/1K2oNvT Thu, 07 May 2015 07:48:59 -0400 http://bit.ly/1HafTsD In a study that could open doors for new applications of photonics from molecular sensing to wireless communications, scientists have discovered a new method to tune the light-induced vibrations of nanoparticles through slight alterations to the surface to which the particles are attached. 
]]> http://bit.ly/1HafTsD Thu, 07 May 2015 10:01:40 -0400 http://bit.ly/1HafTsI Scientists have found a way to control heat propagation in photonic nano-sized devices, which will be used for high speed communications and quantum information technologies. 
]]> http://bit.ly/1HafTsI Thu, 07 May 2015 10:26:46 -0400 http://bit.ly/1K2oOA3 Engineers have devised a process to repair leaksin graphene, filling cracks and plugging holes using a combination of chemical deposition and polymerization techniques. The team then used a process it developed previously to create tiny, uniform pores in the material, small enough to allow only water to pass through. ]]> http://bit.ly/1K2oOA3 Thu, 07 May 2015 14:32:37 -0400 http://bit.ly/1K2oOA4 Researchers have succeeded in creating a new 'whispering gallery' effect for electrons in a sheet of graphene - making it possible to precisely control a region that reflects electrons within the material. They say the accomplishment could provide a basic building block for new kinds of electronic lenses, as well as quantum-based devices that combine electronics and optics. 
]]> http://bit.ly/1K2oOA4 Thu, 07 May 2015 14:31:44 -0400 http://bit.ly/1K2oNvY The National Nanotechnology Coordination Office (NNCO) will hold the second in a series of free webinars focusing on the experiences, successes, and challenges for small- and medium-sized nanotechnology businesses and on issues of interest to the nanotechnology business community on Wednesday May 20, 2015 from 2-3pm EDT. ]]> http://bit.ly/1K2oNvY Thu, 07 May 2015 15:00:17 -0400 http://bit.ly/1HafRB5 The National Nanotechnology Coordination Office (NNCO) has announced the winner of the first EnvisioNano nanotechnology image contest for students. 
]]> http://bit.ly/1HafRB5 Wed, 06 May 2015 02:18:49 -0400 http://bit.ly/1K2oNMh Scientists are inching closer to developing a nano-scale drug delivery system with the aim of specifically targeting cancer cells. 
]]> http://bit.ly/1K2oNMh Wed, 06 May 2015 08:45:44 -0400 http://bit.ly/1K2oOQl Scientists are reporting progress toward that goal with the development of a novel DNA-based GPS. 
]]> http://bit.ly/1K2oOQl Wed, 06 May 2015 09:51:05 -0400 http://bit.ly/1HafTIZ Scientists have developed a simple, thermometer-like device that could help doctors diagnose heart attacks with minimal materials and cost. 
]]> http://bit.ly/1HafTIZ Wed, 06 May 2015 09:56:34 -0400 http://bit.ly/1K2oNMi Researchers devise new technique to produce long, custom-designed DNA strands. ]]> http://bit.ly/1K2oNMi Wed, 06 May 2015 11:33:28 -0400 http://bit.ly/1HafRB8 Researchers developed an inkjet printing technology to produce kesterite thin film absorbers (CZTSSe). Based on the inkjet-printed absorbers, solar cells with total area conversion efficiency of up to 6.4 % have been achieved. 
]]> http://bit.ly/1HafRB8 Wed, 06 May 2015 13:02:48 -0400 http://bit.ly/1HafRB9 Technology in common household humidifiers could enable the next wave of high-tech medical imaging and targeted medicine, thanks to a new method for making tiny silicone microspheres. 
]]> http://bit.ly/1HafRB9 Wed, 06 May 2015 13:15:55 -0400 http://bit.ly/1K2oOQs Some substances, when they undergo a process called rapid-freezing or supercooling, remain in liquid form - even at below-freezing temperatures. A new study is the first to break down the rules governing the complex process of crystallization through rapid-cooling. Its findings may revolutionize the delivery of drugs in the human body, providing a way to 'freeze' the drugs at an optimal time and location in the body. ]]> http://bit.ly/1K2oOQs Wed, 06 May 2015 13:30:05 -0400 http://bit.ly/1HafUwA Electronics is based on the manipulation of electrons and other charge carriers, but in addition to charge, electrons possess a property known as spin. When spin is manipulated with magnetic and electric fields, the result is a spin-polarised current that carries more information than is possible with charge alone. Spin-transport electronics, or spintronics, is a subject of active investigation within Europe's Graphene Flagship. 
]]> http://bit.ly/1HafUwA Tue, 05 May 2015 05:50:24 -0400 http://bit.ly/1HafUwB Researchers have found that covering an implantable neural electrode with nanoporous gold could eliminate the risk of scar tissue forming over the electrode?s surface. 
]]> http://bit.ly/1HafUwB Tue, 05 May 2015 06:06:12 -0400 http://bit.ly/1HafTJ6 Researchers have developed an inexpensive technique called 'microcombing' to align carbon nanotubes (CNTs), which can be used to create large, pure CNT films that are stronger than any previous such films. The technique also improves the electrical conductivity that makes these films attractive for use in electronic and aerospace applications. 
]]> http://bit.ly/1HafTJ6 Tue, 05 May 2015 06:13:20 -0400 http://bit.ly/1HafTJ7 Researchers have discovered topologically protected one-dimensional electron conducting channels at the domain walls of bilayer graphene. These conducting channels are 'valley polarized', which means they can serve as filters for electron valley polarization in future devices such as quantum computers. 
]]> http://bit.ly/1HafTJ7 Tue, 05 May 2015 06:19:22 -0400 http://bit.ly/1HafUwD Researchers have found that silver nanoparticles produced with an extract of wormwood, an herb with strong antioxidant properties, can stop several strains of the deadly fungus phytophthora. ]]> http://bit.ly/1HafUwD Tue, 05 May 2015 06:22:27 -0400 http://bit.ly/1K2oOQt Researchers successfully fabricated halide organic-inorganic hybrid perovskite field-effect transistors and measure their electrical characteristics at room temperature. ]]> http://bit.ly/1K2oOQt Tue, 05 May 2015 08:57:12 -0400