Intelligent absorbent removes radioactive material from water

Professor Huai-Yong Zhu from QUT Chemistry with the titanate nanofiber that can remove radioactive material from contaminated water

Nuclear power plants are located close to sources of water, which is used as a coolant to handle the waste heat discharged by the plants. This means that water contaminated with radioactive material is often one of the problems to arise after a nuclear disaster. Researchers at Australia's Queensland University of Technology (QUT) have now developed what they say is a world-first intelligent absorbent that is capable of removing radioactive material from large amounts of contaminated water, resulting in clean water and concentrated waste that can be stored more efficiently.
The new absorbent, which was developed by a QUT research team led by Professor Huai-Yong Zhu working in collaboration with the Australian Nuclear Science and Technology Organisation (ANSTO) and Pennsylvania State University, uses titanate nanofiber and nanotube technology. Unlike current clean-up methods, such as a layered clays and zeolites, the new material is able to efficiently lock in deadly radioactive material from contaminated water and the used absorbents can then be safely disposed of without the risk of leakage - even if the material were to become wet.
When the contaminated water is run through the fine nanotubes and fibers, the radioactive Cesium (Cs+) ions are trapped through a structural change. Additionally, by adding silver oxide nanocrystals to the outer surface, the nanostructures are able to capture and immobilize radioactive iodine (I-) ions used in treatments for thyroid cancer, in probes and markers for medical diagnosis, and also found in leaks of nuclear accidents.
"One gram of the nanofibres can effectively purify at least one ton of polluted water," Professor Zhu said. "This saves large amounts of dangerous water needing to be stored somewhere and also prevents the risk of contaminated products leaking into the soil."
"Australia is one of the largest producers of titania that are the raw materials used for fabricating the absorbents of titanate nanofibres and nanotubes. Now with the knowledge to produce the adsorbents, we have the technology to do the cleaning up for the world," added Professor Zhu.

Researchers identify enzyme that holds key to living longer through calorie restriction

Restricting calorie intake has been shown to delay the aging process and the enzyme Prx1 has been identified as playing a major role

Studies have shown that restricting the intake of calories without reducing the intake of vitamins and minerals slows the sign of aging process in a wide range of animals including monkeys, rats and fish, and even some fungi. More recent studies provide evidence that calorie restriction can also have the same effect on humans and now researchers at the University of Gothenburg have identified one of the enzymes they claim plays a major role in the aging process.
Although calorie restriction has been shown to slow the aging process, delay the development of age-related diseases and have favorable effects on health, researchers have had a hard time explaining why this is so. Using yeast as a model, researchers at the University of Gothenburg have successfully identified that active peroxiredoxin 1 (Prx1), an enzyme that breaks down harmful hydrogen peroxide in the cells, is required for caloric restriction to work effectively.
The research team's study showed that Prx1 is damaged during aging and loses its activity but caloric restriction counteracts this by increasing the production of another enzyme called Srx1, which repairs Prx1. In potentially good news for those that like their food, the team also found that aging can be delayed without caloric restriction by increasing the quantity of Srx1 in the cell.
"Impaired Prx1 function leads to various types of genetic defects and cancer. Conversely, we can now speculate whether increased repair of Prx1 during aging can counteract, or at least delay, the development of cancer," said Mikael Molin of the University of Gothenburg's Department of Cell and Molecular Biology.
The researchers say that it has also been shown that peroxiredoxins are capable of preventing proteins from being damaged and aggregating, a process that has been linked to several age-related disorders affecting the nervous system, such as Alzheimer's and Parkinson's. Therefore, they are also considering whether stimulation of Prx1 can reduce and delay such disease processes.
The University of Gothenburg team's study, Life Span Extension and H2O2 Resistance Elicited by Caloric Restriction Require the Peroxiredoxin Tsa1 in Saccharomyces cerevisiae has been published in the journal Molecular Cell.

New paper-based explosives sensor is made with an ink jet printer

Wireless explosives sensor that has been inkjet-printed on photographic paper 

There's never been a greater need for explosives detectors. From detecting IEDs on the battlefields of Afghanistan to screening cargoes at airports and sea terminals for bombs or illegal arms shipments, the need to seek out and identify explosives means deploying detectors to hundreds of thousands of locations around the world. Unfortunately, there has always been an unpleasant trade off when it comes to explosives detection sensors - they are either cheap, but not very sensitive or they are very sensitive, but also expensive. They are also often difficult to manufacture, use a good deal of power, are relatively delicate and require a trained operator.

Along with traditional sniffer dogs, many ideas are under development to improve explosives detection technology such as lasers, UV-sensitive sprays, terrahertz radiation scanners and even sensors using bee-venom
. Most of the very sensitive sensors that can detect very minute quantities of explosives at a distance are based on ion mobility spectrometers (IMS). Put simply, these work by ionizing the molecules in an air sample and then measuring how fast they pass through a "drift tube". It's a very sensitive and accurate way of detecting tiny traces of explosives, but it still suffers from requiring very expensive, hard to construct equipment. If only there was an alternative that was potentially as sensitive, but as cheap as printing a document. Then it would be possible to deploy detectors far and wide at much lower cost.
It turns out, there is now such an alternative. At the Georgia Tech Research Institute (GTRI), a team lead by principal research scientist Dr. Krishna Naishadham have created an ink-jet printable ammonia sensor capable of cheap, practical explosives detection. Ammonia is a key ingredient in the manufacture of many explosives.
The process of creating the sensor involves printing carbon nanotubes on paper or "paper-like" materials, such as the plastic polyethylene terephthalate. The ink consists of silver nanoparticles held in an emulsion that can be passed through an ink-jet printer at a temperature of only 212 F (100 C). This ink is treated with ultrasonic waves in a process known as sonification, which alters the viscosity and makes the ink more homogeneous for greater effectiveness. As it sets, the ink forms into nanoscale cylinders called nanotubes. These are only one-billionth of a meter in diameter-about 1/50,000th the width of a human hair. When these nanotubes are coated with a conductive polymer that attracts ammonia it becomes an effective explosives sensor capable of detecting trace amounts of ammonia as low as five parts per million. With different coatings, the nanotubes can detect other gases.

Xiaojuan (Judy) Song and Krishna Naishadham and display two prototype wireless explosives detector devices (Photo: Greg Meek, Georgia Tech)

Explosives detector and communication device

Not only is this process cheap and effective, but the nanotubes can also be formed into RF circuits, components and antennae. This means that the sensor can be printed with a built-in communications device already installed to transmit data. These components can be printed on a suitable plastic and be formed out of flexible organic materials, such as liquid crystal polymer to make them more robust and water resistant. The device also uses very little power, which makes it suitable for running off of thin-film batteries or solar cells. And, being printed, the device can be stuck on any surface where it might be required. The GTRI team is also working to make the device capable of operating passively without an internal power source-something like RFID tags used in shops that get their power from the shop's scanning devices..
This makes for a very flexible little package. The GTRI team designed the detector to act as an integrated detection/transmission system that provides stand-off explosives detection that allows personnel to remain at a safe distance while the detector transmits the results back to the operators.
"This prototype represents a significant step toward producing an integrated wireless system for explosives detection, says Dr. Naishadham. "It incorporates a sensor and a communications device in a small, low-cost package that could operate almost anywhere."
If it lives up to its promise, the printable explosives detector could deliver vitally needed, life-saving detectors that can be mass produced cheaply in any corner of the world.