Articles from January 2013

How to Extend Tenfold Integrated Circuit Battery Life

Researchers at Rochester Institute of Technology, international semiconductor consortium SEMATECH and Texas State University have demonstrated that use of new methods and materials for building integrated circuits can reduce power—extending battery life to 10 times longer for mobile applications compared to conventional transistors.
nano integrated circuits
“The tunneling field effect transistors have not yet demonstrated a sufficiently large drive current to make it a practical replacement for current transistor technology,” says Sean Rommel, an associate professor of electrical and microelectronic engineering. “But this work conclusively established the largest tunneling current ever experimentally demonstrated”, providing a practical basis for low-voltage transistor technologies.


Effective DNA Vaccine Without Syringe

MIT researchers describe a new type of vaccine-delivery film that holds promise for improving the effectiveness of DNA vaccines. If such vaccines could be successfully delivered to humans, they could overcome not only the safety risks of using viruses to vaccinate against diseases such as HIV, but they would also be more stable, making it possible to ship and store them at room temperature.
polymer vaccine
This type of vaccine delivery would also eliminate the need to inject vaccines by syringe, says Darrell Irvine, an MIT professor of biological engineering and materials science and engineering. “You just apply the patch for a few minutes, take it off and it leaves behind these thin polymer films embedded in the skin,” he says.

Hydrogen On Demand

New technology could help power portable devices like satellite phones and radios. University at Buffalo researchers demonstrate that super-small particles of silicon react with water to produce hydrogen almost instantaneously. In a series of experiments, the scientists created spherical silicon particles about 10 nanometers in diameter. When combined with water, these particles reacted to form silicic acid (a nontoxic byproduct) and hydrogen — a potential source of energy for fuel cells. The reaction didn’t require any light, heat or electricity, and also created hydrogen about 150 times faster than similar reactions using silicon particles 100 nanometers wide, and 1,000 times faster than bulk silicon, according to the study.
hydrogen from nanoparticle
When it comes to splitting water to produce hydrogen, nanosized silicon may be better than more obvious choices that people have studied for a while, such as aluminum,” said researcher Mark T. Swihart, UB professor of chemical and biological engineering and director of the university’s Strategic Strength in Integrated Nanostructured Systems. The scientists were able to verify that the hydrogen they made was relatively pure by testing it successfully in a small fuel cell that powered a fan.

New Conductive NanoMaterial Revolutionises Electronics

Scientists at CSIRO and RMIT University in Australia have produced a new two-dimensional material that will revolutionise the electronics market, making “nano” more than just a marketing term. The researchers have adapted a revolutionary material known as graphene to create a new conductive nano-material. The material – made up of layers of crystal known as molybdenum oxides – has unique properties that encourage the free flow of electrons at ultra-high speeds.
layered molybdenum oxide crystal lattice

Within these layers, electrons are able to zip through at high speeds with minimal scattering,” Dr Zhuiykov said. “The importance of our breakthrough is how quickly and fluently electrons – which conduct electricity – are able to flow through the new material.”
RMIT’s Professor Kourosh Kalantar-zadeh said the researchers were able to remove “road blocks” that could obstruct the electrons, an essential step for the development of high-speed electronics.
Instead of scattering when they hit road blocks, as they would in conventional materials, they can simply pass through this new material and get through the structure faster,” Professor Kalantar-zadeh said.
Quite simply, if electrons can pass through a structure quicker, we can build devices that are smaller and transfer data at much higher speeds.


How To Combat Overheating In Mobile Phones

A team of scientists from Tyndall National Institute at University College Cork and the National University of Singapore have found new ways to combat overheating in mobile phones and laptops, and could also aid in electrical stimulation of tissue repair for wound healing. By finding out how molecules behave in these devices, a ten-fold increase in switching efficiency was obtained by changing just one carbon atom. Dr. Damien Thompson at the Tyndall National Institute, UCC and a team of researchers at the National University of Singapore led by Prof. Chris Nijhuis designed and created the devices, which are based on molecules acting as electrical valves, or diode rectifiers.

molecules pack together

These molecules are very useful because they allow current to flow through them when switched ON and block current flow when switched OFF. The results of the study show that simply adding one extra carbon is sufficient to improve the device performance by more than a factor of ten. We are following up lots of new ideas based on these results, and we hope ultimately to create a range of new components for electronic devices,” explains Dr. Damien Thompson.

Electric Car: Larger, Safer Lithium-Ion Batteries

Looking toward improved batteries for charging electric cars and storing energy from renewable but intermittent solar and wind, scientists at Oak Ridge National LaboratoryORNL-have developed the first high-performance, nanostructured solid electrolyte for more energy-dense lithium ion batteries.
Today’s lithium-ion batteries rely on a liquid electrolyte, the material that conducts ions between the negatively charged anode and positive cathode. But liquid electrolytes often entail safety issues because of their flammability, especially as researchers try to pack more energy in a smaller battery volume. Building batteries with a solid electrolyte, as ORNL researchers have demonstrated, could overcome these safety concerns and size constraints.
To make a safer, lightweight battery, we need the design at the beginning to have safety in mind,” said ORNL‘s Chengdu Liang, who led the newly published study in the Journal of the American Chemical Society. “We started with a conventional material that is highly stable in a battery system – in particular one that is compatible with a lithium metal anode.”


Make Cancer Cells Starve to Death

How do you annihilate lymphoma without using any drugs? Starve it to death by depriving it of what appears to be a favorite food: HDL cholesterol. Northwestern Medicine® researchers discovered this with a new nanoparticle that acts like a secret double agent. It appears to the cancerous lymphoma cell like a preferred meal – natural HDL. But when the particle engages the cell, it actually plugs it up and blocks cholesterol from entering. Deprived of an essential nutrient, the cell eventually dies. A new study by C. Shad Thaxton, MD, assistant professor in urology, and Leo Gordon, MD, Abby and John Friend Professor of Oncology Research, shows that synthetic HDL nanoparticles killed B-cell lymphoma, the most common form of the disease, in cultured human cells, and inhibited human B-cell lymphoma tumor growth in mice.
gold nanoparticles_250
Northwestern Medicine® researchers have discovered a new nanoparticle that acts like a secret double agent. The nanoparticle – originally developed by C. Shad Thaxton, MD, as a possible therapy for heart disease – closely mimics the size, shape, and surface chemistry of natural HDL particles. But it has one key difference: a five nanometer gold particle at its core. After it attaches to a lymphoma cell, the gold particle’s spongy surface helps to kill it.
This has the potential to eventually become a nontoxic treatment for B-cell lymphoma which does not involve chemotherapy,” said Gordon, a co-corresponding author with Thaxton on the paper. “It’s an exciting preliminary finding.” The paper was published on Monday, January 21, in the journal Proceedings of the National Academy of Sciences.

Reducing Lengh Makes Carbon Nanotube Non Toxic

Safety fears about carbon nanotubes, due to their structural similarity to asbestos, have been alleviated following research showing that reducing their length removes their toxic properties. A University College London UCL -team, showed evidence that the asbestos-like reactivity and pathogenicity reported for long, pristine nanotubes can be completely alleviated if their surface is modified and their effective length is reduced as a result of chemical treatment. The finding has been published in in the journal Angewandte Chemie.
The apparent structural similarity between carbon nanotubes and asbestos fibres has generated serious concerns about their safety profile and has resulted in many unreasonable proposals of a halt in the use of these materials even in well-controlled and strictly regulated applications, such as biomedical ones. What we show for the first time is that in order to design risk-free carbon nanotubes both chemical treatment and shortening are needed”, said Professor Kostas Kostarelos, Chair of Nanomedicine at the UCL School of Pharmacy who led the research with his long term collaborators Doctor Alberto Bianco of the CNRS in Strasbourg, France and Professor Maurizio Prato of the University of Trieste, Italy.

New Solar Cell 40% More Efficient

The silicon solar cells that are used to supply electricity for domestic use are relatively cheap, but inefficient because they are only able to utilise a limited part of the effect of the sunlight. The reason is that one single material can only absorb part of the spectrum of the light. Now researchers at Lund University in Sweden have shown how nanowires could pave the way for more efficient and cheaper solar cells. Research on solar cell nanowires is on the rise globally. Until now the unattained dream figure was ten per cent efficiency – but now Dr Borgström and his colleagues are able to report an efficiency of 13.8 per cent.
Our findings are the first to show that it really is possible to use nanowires to manufacture solar cells”, says Magnus Borgström, a researcher in semiconductor physics and the principal author.

Solar Cells: Huge Improvement in Light Absorption

Scientists at Aalto University – Finland, have demonstrated results that show a huge improvement in the light absorption and the surface passivation of silicon nanostructures. This has been achieved by applying atomic layer coating. The results advance the development of devices that require high sensitivity light response such as high efficiency solar cells.
– This method provides extremely good surface passivation. Simultaneously, it reduces the reflectance further at all wavelengths.These results are very promising considering the use of black silicon (b-Si) surfaces on solar cells to increase the efficiency to completely new levels, tells researcher scientist. Päivikki Repo.
More effective surface passivation methods than those used in the past have been needed to make black silicon a viable material for commercial applications. Good surface passivation is crucial in photonic applications such as solar cells. The research has just been published in the Journal of Photovoltaics. The research is carried out by Aalto University, Finland, together with experts from Fraunhofer Institute for Solar Energy Systems ISE, Germany.

How To Cleanup Contaminated Fukushima Nuclear Plants

Researchers at Rice University and Lomonosov Moscow State University have found Graphene oxide has a remarkable ability to quickly remove radioactive material from contaminated water. This collaborative effort by the Rice lab of chemist James Tour and the Moscow lab of chemist Stepan Kalmykov determined that microscopic, atom-thick flakes of graphene oxide bind quickly to natural and human-made radionuclides and condense them into solids. The flakes are soluble in liquids and easily produced in bulk. The discovery, Tour said, could be a boon in the cleanup of contaminated sites like the Fukushima nuclear plants damaged by the 2011 earthquake and tsunami. It could also cut the cost of hydraulic fracturing (“fracking”) for oil and gas recovery and help reboot American mining of rare earth metals, he said.
Atomic radiation
In the probabilistic world of chemical reactions where scarce stuff (low concentrations) infrequently bumps into something with which it can react, there is a greater likelihood that the ‘magic’ will happen with graphene oxide than with a big old hunk of bentonite,” said Steven Winston, a former vice president of Lockheed Martin and Parsons Engineering and an expert in nuclear power and remediation who is working with the researchers. “In short, fast is good.


Nanoscale ‘Bed of Nails’ for Drug Delivery

Researchers at North Carolina State University have come up with a technique to embed needle-like carbon nanofibers in an elastic membrane, creating a flexible “bed of nails” on the nanoscale that opens the door to development of new drug-delivery systems. The research community is interested in finding new ways to deliver precise doses of drugs to specific targets, such as regions of the brain. One idea is to create balloons embedded with nanoscale spikes that are coated with the relevant drug. Theoretically, the deflated balloon could be inserted into the target area and then inflated, allowing the spikes on the balloon’s surface to pierce the surrounding cell walls and deliver the drug. The balloon could then be deflated and withdrawn.

This image shows carbon nanofibers embedded in the elastic membrane.
We have now developed a way of embedding carbon nanofibers in an elastic silicone membrane and ensuring that the nanofibers are both perpendicular to the membrane’s surface and sturdy enough to impale cells,” says Dr. Anatoli Melechko, an associate professor of materials science and engineering at NC State and co-author of a paper on the work.