(NanoRealm) - Will we soon be plugging our mobile phone into our t-shirt instead of putting in a battery? This vision is not totally out of reach: the first steps in this direction have already been taken.

Now a team led by Zhong Lin Wang at the Georgia Institute of Technology (Atlanta, USA) and Jong Min Kim of Samsung Electronics in South Korea is introducing a prototype for a flexible energy storage device that can be worked into textiles. As the scientists report in the journal Angewandte Chemie, this supercapacitor is made of a very special arrangement of zinc oxide nanowires grown on conventional fibers.

Although smaller, lighter components are constantly being developed, most devices for energy generation and storage are much too bulky and heavy for increasingly miniaturized electronic devices of the future. Supercapacitors are an interesting alternative to batteries and rechargeable batteries for energy storage. They can be recharged almost endlessly and extremely fast; however, previous examples have not been flexible or light enough.

The research team has now developed a prototype for a high-efficiency fiber-based electrochemical micro-supercapacitor that uses zinc oxide nanowires as electrodes. The substrate for one of the electrode is a flexible, fine plastic wire; for the other electrode it is a fiber made of Kevlar. Kevlar is the material used to make bulletproof vests. The researchers were able to grow zinc oxide nanowires on each of these substrates. Additional coatings with materials like gold and manganese oxide could further improve the charge capacitance. Using tweezers, the researchers then wrapped each of the plastic wires with a Kevlar fiber. This assembly was then embedded in a solid gel electrolyte that separates the two electrodes and allows for the necessary charge transport. A bundle of these fibers could be processed to form a thread.


Zinc oxide has special advantages over conventional supercapacitor materials,: it can be grown on any desired substrate in any form at low temperature (below 100 °C) and it is both biocompatible and environmentally friendly.

A particularly intriguing application would be the use of these new charge-storage media in combination with flexible fiber nanogenerators, which Wang and his team have previously developed. The wearer’s heartbeat and steps, or even a light wind, would be enough to move the piezoelectric zinc oxide nanowires in the fibers, generating electrical current.

In the form of a "power shirt" such a system could deliver enough current for small electronic devices, such as mobile phones or small sensors like those used to warn firemen of toxins.

For More information: Zhong Lin Wang, Fiber Supercapacitors Made of Nanowire-Fiber Hybrid Structures for Wearable/Flexible Energy Storage, Angewandte Chemie International Edition,
http://dx.doi.org/10.1002/anie.201006062

(NanoRealm) - In a revolutionary leap that could transform solar power from a marginal, boutique alternative into a mainstream energy source, MIT researchers have overcome a major barrier to large-scale solar power: storing energy for use when the sun doesn't shine.

Inspired by the photosynthesis performed by plants, Nocera and Matthew Kanan, a postdoctoral fellow in Nocera's lab, have developed an unprecedented process that will allow the sun's energy to be used to split water into hydrogen and oxygen gases. Later, the oxygen and hydrogen may be recombined inside a fuel cell, creating carbon-free electricity to power your house or your electric car, day or night.

The key component in Nocera and Kanan's new process is a new catalyst that produces oxygen gas from water; another catalyst produces valuable hydrogen gas. The new catalyst consists of cobalt metal, phosphate and an electrode, placed in water. When electricity — whether from a photovoltaic cell, a wind turbine or any other source — runs through the electrode, the cobalt and phosphate form a thin film on the electrode, and oxygen gas is produced.





Combined with another catalyst, such as platinum, that can produce hydrogen gas from water, the system can duplicate the water splitting reaction that occurs during photosynthesis.

The new catalyst works at room temperature, in neutral pH water, and it's easy to set up, Nocera said. "That's why I know this is going to work. It's so easy to implement," he said.

'Just the beginning'

Currently available electrolyzers, which split water with electricity and are often used industrially, are not suited for artificial photosynthesis because they are very expensive and require a highly basic (non-benign) environment that has little to do with the conditions under which photosynthesis operates.

More engineering work needs to be done to integrate the new scientific discovery into existing photovoltaic systems, but Nocera said he is confident that such systems will become a reality.

"This is just the beginning," said Nocera, principal investigator for the Solar Revolution Project funded by the Chesonis Family Foundation and co-Director of the Eni-MIT Solar Frontiers Center. "The scientific community is really going to run with this."

Nocera hopes that within 10 years, homeowners will be able to power their homes in daylight through photovoltaic cells, while using excess solar energy to produce hydrogen and oxygen to power their own household fuel cell. Electricity-by-wire from a central source could be a thing of the past.

The project is part of the MIT Energy Initiative, a program designed to help transform the global energy system to meet the needs of the future and to help build a bridge to that future by improving today's energy systems. MITEI Director Ernest Moniz, Cecil and Ida Green Professor of Physics and Engineering Systems, noted that "this discovery in the Nocera lab demonstrates that moving up the transformation of our energy supply system to one based on renewables will depend heavily on frontier basic science."

The success of the Nocera lab shows the impact of a mixture of funding sources — governments, philanthropy, and industry. This project was funded by the National Science Foundation and by the Chesonis Family Foundation, which gave MIT $10 million this spring to launch the Solar Revolution Project, with a goal to make the large scale deployment of solar energy within 10 years.

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Source: MIT News - http://web.mit.edu/newsoffice/2008/oxygen-0731.html

(NanoRealm) - THE use of nano technology has helped the Government save RM3.44bil worth of subsidised diesel fuel from being smuggled out of the country between 2006 to 2008.

Nano technology ‘helped govt save RM3.44bil’

Domestic Trade, Cooperative and Consumerism Minister Datuk Seri Ismail Sabri Yaakob said the Nanotag technology or “mark” to identify subsidised fuel had helped enforcement officers track or identify subsidised diesel and to take legal action against the culprits.

“The Nanotag technology has enabled our officers to check the distribution of subsidised diesel from 36 diesel fuel depots throughout the country, including 15 depots in Sabah and Sarawak,” he said.

“Since the programme was introduced in 2006, a total of 594 legal cases were filed and 6.86mil litres of diesel seized from those who had abused the diesel fuel subsidy programme,” Ismail said in winding up the debate in his ministry at the committee stage.

It was reported that the Gover nment had suffered losses in terms of subsidies, ranging from RM1bil in 2003 to RM3bil in 2006 before the Nanotag technology was introduced.

On the contract of Teras Kimia Sdn Bhd, which was tasked to carry out the tagging of diesel supplies at fuel depots, Ismail said he was informed that the company’s services would end this year.

“The company had asked for an extension and we are still discussing this with the Finance Ministry,” he added.

Ismail also said the Government had to raise the subsidy payment for sugar due to the increase in global sugar prices. “The Government also wants to reduce the sugar subsidy payments of about RM1bil annually.

“The idea of imposing a uniform price for sugar among Asean countries will help reduce smuggling, but it means that we have to increase the sugar price in Malaysia as it is lower than in other Asean countries.”

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Source: http://thestar.com.my/news/story.asp?file=/2010/4/20/parliament/6087587&sec=parliament

(NanoRealm) - A team of scientists has developed a way to control the direction of light on the nanoscale, by developing miniaturized television aerials made from gold nanorods, which can pave the way for quantum computing networks in the future.

At the moment, quantum physicists use cumbersome apparatus to try to keep track of photons, for instance, building large vacuum cavities with mirrored walls to guide light.

"It's funny that to control the small quantum world, you need huge pieces of equipment," said Holger Hofmann, at the Department of Quantum Matter at Hiroshima University in Japan.

Now, according to a report in Nature News, Hofmann and his colleagues have developed a way to control the direction of light on the nanoscale.

Their technique is based on the workings of the 'Yagi-Uda' antenna commonly used to transmit and detect radio waves and often seen on rooftops as television aerials.

Hofmann stumbled on the idea by accident, while teaching his electromagnetism class how antennas work.

"The textbook didn't explain it well, and while trying to come up with my own picture, I realized that the same technique could work on the nanoscale," he said.

A standard Yagi-Uda antenna is made up of a set of parallel metal rods that gradually decrease in length.

An electrical signal is fed into the second longest rod, setting it vibrating and producing a driving electromagnetic wave that spreads out in all directions.

This stimulates the neighbouring rods to oscillate and emit secondary waves.

Both the length and spacing of adjacent rods are carefully set at fractions of the wavelength of the driving wave, so that the secondary waves interfere with the driving wave, amplifying it along the forward direction and reducing it along the sideways and backward directions.

Hofmann and his colleagues realized that gold nanorods should produce the same effect on the nanoscale - but here, the length-to-width ratio of the rods, rather than their length and spacing, is important.

The team etched their mini gold antenna into a glass substrate and drove it directly with red laser light.

The tricky part was to ensure that just one nanorod was driven by the incoming light, just as only one metal rod is in the Yugi-Uda antenna.

To ensure this, the team tilted the chosen nanorod by 45 degrees relative to its neighbours and stimulated it using laser light that was polarized at the same angle.

They then monitored the direction of light transmitted out of the glass substrate.

The result was actually better than their theory predicted, according to Hoffman, with roughly two-thirds of the input light being directed largely forwards. (ANI)

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Provdied by ANI
Souce: Sifynews (http://sify.com/news/nano-antennas-could-pave-way-for-quantum-computing-networks-news-international-kdpn4ddagfc.html)

(NanoRealm) - While scientists have become rather adept at transforming generic skin cells into specialized organ cells, crafting the organs themselves has proven far more difficult. Since the 3-D architecture of most organs is as important to their function as their cellular makeup, 2-D cell cultures are not very useful for building a replacement heart from scratch. To solve that problem, most organ makers create a scaffolding for the cells to grow on.

For a team of researchers at Rice University, even a biodegradable scaffolding wasn't good enough. By injecting cells with a metallic gel, the researchers have succeeded in suspending cultured cells in a three-dimensional magnetic field. With this magnetic scaffolding, organs can be grown in the right shape, and with no foreign material.

The researchers used bacteriophages, special viruses that inject themselves into cells, to insert a polymer iron oxide gel into brain cancer cells. Once the cells absorbed the magnetic gel, the Rice scientists levitated the cells in a weak magnetic field. And since cells naturally live in a 3-D space, not a 2-D culture, the brain cancer cells actually behaved more normally while suspended in the magnetic field then they did when in a cell culture.
The obvious next step involved programming detailed magnetic fields that float stem cells in the exact spots needed for them to grow into a full organ. To that end, the researchers have sold the technology to the company n3D Bioscences. Whether or not this process leaves your replacement organ magnetic, and how that will affect getting through airports, remains to be seen.

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Source: PopSci - http://www.popsci.com/science/article/2010-03/metal-nano-particles-suspend-human-cells-magnetic-scaffolding-organ-manufactoring

(NanoRealm) - Researchers at MIT are working on getting computer chips to "self assemble" by coaxing molecules to arrange themselves into tiny but useful patterns, a process that could lead to microprocessors with much smaller circuit elements.

In the journal Nature Nanotechnology this week, the researchers describe a process that could become an alternative to conventional photolithography, which relies on light projected onto a photo-sensitive material, as people continue to forecast the demise of Moore's Law. That observation states that the number of transistors that can be placed on an integrated circuit doubles roughly every two years.
Led by Caroline Ross and Karl Berggren, both engineering professors, the scientists used electron beam lithography to create nanoscale "posts" on a silicon chip. They then deposited copolymers--large molecules of two polymers with repeating structural units--on the chip. The copolymers spontaneously linked to the posts and arranged themselves into useful patterns.
The polymers naturally want to separate from each other, thus causing them to arrange in predictable ways. (Berggren compares compares different polymer molecules to the characters played by Robert De Niro and Charles Grodin in "Midnight Run"--a bounty hunter and a white-collar criminal who are handcuffed together but can't stand each other.)
A variety of patterns that can be used in circuit design could be achieved by changing the shape and position of the posts, the proportions of the polymers, and the length of the molecule chains, MIT said.
When exposed to plasma, one polymer burns away, while the other turns to glass. The latter could work like a photoresist in optical lithography (a photoresist is a light-sensitive material onto which light is projected to form a pattern for the chip).
The team is still working to produce functioning circuits in a prototype chip, and to create even smaller chip features with the copolymer technique.

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Source: CNet (http://news.cnet.com/8301-17938_105-10468870-1.html)

(NanoRealm) - A team at Cornell University has developed a technique to permanently coat cotton fibers with electrically conductive nanoparticles. The result makes cotton electronically conductive, while continuing to be lightweight, flexible, and comfortable.

The innovation came from the work of Juan Hinestroza and his colleagues at universities in Bologna and Cagliari, Italy. Dr. Hinestroza, currently an assistant professor of Fiber Science and Apparel Design, earned degrees in chemical and biomolecular engineering from his native country, Columbia, and Tulane University. His research specializes in creating multifunctional fibers by manipulation of nanoscale phenomena.

Focus: Modify, Create and Develop

His work has three focus points: modification of existing textile materials, creation of fibers from polymers, and "development of mathematical models and metrology tools based on scanning probe microscopy to assess nanoscale phenomena on low energy surfaces and high radius of curvature". Nanofibers could be used in, antibacterial, anti-odor, active camouflage and anti-counterfeiting applications. Dr. Hinestroza has worked with magnetic nanoparticles that can create invisible signatures that mints can inscribe on dollar bills.

As to his efforts with textiles, Dr. Hinestroza said. "Previous technologies have achieved conductivity but the resulting fiber becomes rigid and heavy. Our new techniques make our yarns friendly to further processing such as weaving, sewing and knitting."
The science underlying the new cloth is more familiar to readers in the form of conductive inks or pastes of metals such as silver or copper which can be coated onto glass to form an electrically conductive surface. These metal coated glass substrates are used in chips for electronic components. This science is the subject of many patents, included a patent application related to "conductive nanoparticle substrate and method of manufacture" purporting to have "specific qualities that permit the reflow of solder across the surface for the attachment of electrical components, namely high electrical conductivity, good adhesion, scratch resistance."

Combination of Technology and Fashion Became Reality

Combining the technology with cloth will change the future of fabric. Cotton is the vehicle presently. A theme extolling this fiber, The Fabric Of Our Lives, appeared in 1989. Cotton Incorporated, the research and marketing company representing upland cotton even sings its praises in commercials in a song first performed by Richie Havens and later by Aaron Neville.

Cotton Incorporated began a recycling program in 2006 called Cotton - From Blue to Green. They have recycled enough denim to create natural cotton fiber insulation for over 540 homes. Gap stores are participating in a two week drive giving customers who donate denim a 30 percent discount on new denim purchases through March 14. The donated denims will be converted into UltraTouch Natural Cotton Fiber Insulationand donated to needy communities.

Gap brands include Banana Republic and Old Navy. Other retailers who participate in the Cotton - From Blue to Green program include Guess, Vanity and Warner Bros.

Getting back onto the subject of Cornell's University nano-cotton, It will be interesting to tune in to Cornell’s annual Design League Fashion Show, was held on March 13, 2010.

The theme of this year's show is Once Upon A Runway, and show attendants will see the unveiling of a solar-powered dress designed by Hinestroza's student, Abbey Liebman.

Powering your smartphone or MP3 player while on the move couldn’t be easier. The new design uses flexible solar cells which power small electronics from a USB charger in the waist of the dress. The event gives Liebman and other students involved in design, graphics, photography, and theater production an opportunity to showcase their creativity.

Could wearning nano-cotton be the new fashion of the future? We'll leave that for your consideration.

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Source: Bright Side Of News (http://www.brightsideofnews.com/news/2010/3/11/fashion-the-land-of-cotton-is-going-nanotech.aspx)

(NanoRealm) - For the first time, scientists have succeeded in growing empty particles derived from a plant virus and have made them carry useful chemicals.

The external surface of these nano containers could be decorated with molecules that guide them to where they are needed in the body, before the chemical load is discharged to exert its effect on diseased cells. The containers are particles of the Cowpea mosaic virus, which is ideally suited for designing biomaterial at the nanoscale.

"This is a shot in the arm for all Cowpea mosaic virus technology," says Professor George Lomonossoff of the John Innes Centre, one of the authors on a paper to be published in the specialised nanotechnology scientific journal, Small.
Scientists have previously tried to empty virus particles of their genetic material using irradiation or chemical treatment. Though successful in rendering the particles non-infectious, these methods have not fully emptied the particles.

Scientists at the John Innes Centre, funded by the BBSRC and the John Innes Foundation, discovered they could assemble empty particles from precursors in plants and then extract them to insert chemicals of interest. Scientists at JIC and elsewhere had also previously managed to decorate the surface of virus particles with useful molecules.

"But now we can load them too, creating fancy chemical containers," says lead author Dr Dave Evans.

"This brings a huge change to the whole technology and opens up new areas of research," says Prof Lomonossoff. "We don't really know all the potential applications yet because such particles have not been available before. There is no history of them."
One application could be in cancer treatment. Integrins are molecules that appear on cancer cells. The virus particles could be coated externally with peptides that bind to integrins. This would mean the particles seek out cancer cells to the exclusion of healthy cells. Once bound to the cancer cell, the virus particle would release an anti-cancer agent that has been carried as an internal cargo.

Some current drugs damage healthy cells as well as the cancer, leading to hair loss and other side effects. This technology could deliver the drug in a more targeted way.
"The potential for developing Cowpea mosaic virus as a targeted delivery agent of therapeutics is now a reality," says Dr Evans.

The empty viral particles, their use, and the processes by which they are made, are the subject of a new patent filing. Management of the patent and commercialisation of the technology is being handled by PBL.

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More information: "Cowpea Mosaic Virus Unmodified Empty Virus-Like Particles Can Be Loaded with Metal and Metal Oxide." DOI:10.1002/smll.200902135

Provided by Norwich BioScience Institutes

(NanoRealm) - If harnessing the unlimited solar power of the sun were easy, we wouldn't still have the greenhouse gas problem that results from the use of fossil fuel. And while solar energy systems work moderately well in hot desert climates, they are still inefficient and contribute only a small percentage of the general energy demand. A new solution may be coming from an unexpected source -- a source that may be on your dinner plate tonight.

"Looking at the most complicated membrane structure found in a plant, we deciphered a complex membrane protein structure which is the core of our new proposed model for developing 'green' energy," says structural biologist Prof. Nathan Nelson of Tel Aviv University's Department of Biochemistry. Isolating the minute crystals of the PSI super complex from the pea plant, Prof. Nelson suggests these crystals can be illuminated and used as small battery chargers or form the core of more efficient artificial solar cells.




Nanoscience is the science of small particles of materials and is one of the most important research frontiers in modern technology. In nature, positioning of molecules with sub-nanometer precision is routine, and crucial to the operation of biological complexes such as photosynthetic complexes. Prof. Nelson's research concentrates on this aspect.

The mighty PSI

To generate useful energy, plants have evolved very sophisticated "nano-machinery" which operates with light as its energy source and gives a perfect quantum yield of 100%. Called the Photosystem I (PSI) complex, this complex was isolated from pea leaves, crystalized and its crystal structure determined by Prof. Nelson to high resolution, which enabled him to describe in detail its intricate structure.

"My research aims to come close to achieving the energy production that plants can obtain when converting sun to sugars in their green leaves," explains Prof. Nelson.

Described in 1905 by Albert Einstein, quantum physics and photons explained the basic principles of how light energy works. Once light is absorbed in plant leaves, it energizes an electron which is subsequently used to support a biochemical reaction, like sugar production.

"If we could come even close to how plants are manufacturing their sugar energy, we'd have a breakthrough. It's therefore important to solve the structure of this nano-machine to understand its function," says Prof. Nelson, whose lab is laying the foundations for this possibility.

Since the PSI reaction center is a pigment-protein complex responsible for the photosynthetic conversion of light energy to another form of energy like chemical energy, these reaction centers, thousands of which are precisely packed in the crystals, may be used to convert light energy to electricity and serve as electronic components in a variety of different devices.

"One can imagine our amazement and joy when, upon illumination of those crystals placed on gold covered plates, we were able to generate a voltage of 10 volts. This won't solve our world's energy problem, but this could be assembled in power switches for low-power solar needs, for example," he concludes.

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Adapted from American Friends of Tel Aviv University (http://www.aftau.org/)
Source: Science Daily - http://www.sciencedaily.com/releases/2010/03/100304112237.htm

(NanoRealm) - Consider this T-shirt: It can monitor your heart rate and breathing, analyze your sweat and even cool you off on a hot summer's day. What about a pillow that monitors your brain waves, or a solar-powered dress that can charge your ipod or MP4 player? This is not science fiction - this is cotton in 2010.

Now, the laboratory of Juan Hinestroza, assistant professor of Fiber Science and Apparel Design, has developed cotton threads that can conduct electric current as well as a metal wire can, yet remain light and comfortable enough to give a whole new meaning to multi-use garments. This technology works so well that simple knots in such specially treated thread can complete a circuit - and solar-powered dress with this technology literally woven into its fabric will be featured at the annual Cornell Design League Fashion Show on Saturday, March 13 at Cornell University's Barton Hall.

Using multidisciplinary nanotechnology developed at Cornell in collaboration with the universities at Bologna and Cagliari, Italy, Hinestroza and his colleagues developed a technique to permanently coat cotton fibers with electrically conductive nanoparticles. "We can definitively have sections of a traditional cotton fabric becoming conductive, hence a great myriad of applications can be achieved," Hinestroza said.
"The technology developed by us and our collaborators allows cotton to remain flexible, light and comfortable while being electronically conductive," Hinestroza said. "Previous technologies have achieved conductivity but the resulting fiber becomes rigid and heavy. Our new techniques make our yarns friendly to further processing such as weaving, sewing and knitting."
This technology is beyond the theory stage. Hinestroza's student, Abbey Liebman, was inspired by the technology enough to design a dress that actually uses flexible solar cells to power small electronics from a USB charger located in the waist. The charger can power a smartphone or an MP3 player.

"Instead of conventional wires, we are using our conductive cotton to transmit the electricity -- so our conductive yarns become part of the dress," Hinestroza said. "Cotton used to be called the 'fabric of our lives' but based on these results, we can now call it 'The fabric of our lights.'"

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Provided by Cornell University (http://www.cornell.edu/)
Source: http://www.physorg.com/news187372919.html

(NanoRealm) - Most polymers -- materials made of long, chain-like molecules -- are very good insulators for both heat and electricity. But an MIT team has found a way to transform the most widely used polymer, polyethylene, into a material that conducts heat just as well as most metals, yet remains an electrical insulator.

The new process causes the polymer to conduct heat very efficiently in just one direction, unlike metals, which conduct equally well in all directions. This may make the new material especially useful for applications where it is important to draw heat away from an object, such as a computer processor chip. The work is described in a paper published on March 7 in Nature Materials.

The key to the transformation was getting all the polymer molecules to line up the same way, rather than forming a chaotic tangled mass, as they normally do. The team did that by slowly drawing a polyethylene fiber out of a solution, using the finely controllable cantilever of an atomic force microscope, which they also used to measure the properties of the resulting fiber.
This fiber was about 300 times more thermally conductive than normal polyethylene along the direction of the individual fibers, says the team's leader, Gang Chen, the Carl Richard Soderberg Professor of Power Engineering and director of MIT's Pappalardo Micro and Nano Engineering Laboratories.


The high thermal conductivity could make such fibers useful for dissipating heat in many applications where metals are now used, such as solar hot water collectors, heat exchangers and electronics.

Chen explains that most attempts to create polymers with improved thermal conductivity have focused on adding in other materials, such as carbon nanotubes, but these have achieved only modest increases in conductivity because the interfaces between the two kinds of material tend to add thermal resistance. "The interfaces actually scatter heat, so you don't get much improvement," Chen says. But using this new method, the conductivity was enhanced so much that it was actually better than that of about half of all pure metals, including iron and platinum.
Producing the new fibers, in which the polymer molecules are all aligned instead of jumbled, required a two-stage process, explains graduate student Sheng Shen, the lead author of the paper. The polymer is initially heated and drawn out, then heated again to stretch it further. "Once it solidifies at room temperature, you can't do any large deformation," Shen says, "so we heat it up twice."


Even greater gains are likely to be possible as the technique is improved, says Chen, noting that the results achieved so far already represent the highest thermal conductivity ever seen in any polymer material. Already, the degree of conductivity they produce, if such fibers could be made in quantity, could provide a cheaper alternative to metals used for heat transfer in many applications, especially ones where the directional characteristics would come in handy, such as heat-exchanger fins (like the coils on the back of a refrigerator or in an air conditioner), cell-phone casings or the plastic packaging for computer chips. Other applications might be devised that take advantage of the material's unusual combination of thermal conductivity with light weight, chemical stability and electrical insulation.

So far, the team has just produced individual fibers in a laboratory setting, Chen says, but "we're hoping that down the road, we can scale up to a macro scale," producing whole sheets of material with the same properties.

Ravi Prasher, an engineer at Intel, says that "the quality of the work from Prof. Chen's group has always been phenomenal," and adds that "this is a very significant finding" that could have many applications in electronics. The remaining question, he says, is "how scalable is the manufacturing of these fibers? How easy is it to integrate these fibers in real-world applications?"

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More information: Shen S, Henry A, Tong J, Zheng R, Gang Chen G. Polyethylene nanofibres with very high thermal conductivities. Nature Materials. 7 March 2010.

Provided by Massachusetts Institute of Technology (http://web.mit.edu/)

Source: http://www.physorg.com/news187187249.html

(NanoRealm) - A team of scientists at MIT have discovered a previously unknown phenomenon that can cause powerful waves of energy to shoot through minuscule wires known as carbon nanotubes. The discovery could lead to a new way of producing electricity, the researchers say.

The phenomenon, described as thermopower waves, “opens up a new area of energy research, which is rare,” says Michael Strano, MIT’s Charles and Hilda Roddey Associate Professor of Chemical Engineering, who was the senior author of a paper describing the new findings that appeared in Nature Materials on March 7. The lead author was Wonjoon Choi, a doctoral student in mechanical engineering.

Like a collection of flotsam propelled along the surface by waves traveling across the ocean, it turns out that a thermal wave — a moving pulse of heat — traveling along a microscopic wire can drive electrons along, creating an electrical current.

The key ingredient in the recipe is carbon nanotubes — submicroscopic hollow tubes made of a chicken-wire-like lattice of carbon atoms. These tubes, just a few billionths of a meter (nanometers) in diameter, are part of a family of novel carbon molecules, including buckyballs and graphene sheets, that have been the subject of intensive worldwide research over the last two decades.

A previously unknown phenomenon

In the new experiments, each of these electrically and thermally conductive nanotubes was coated with a layer of a reactive fuel that can produce heat by decomposing. This fuel was then ignited at one end of the nanotube using either a laser beam or a high-voltage spark, and the result was a fast-moving thermal wave traveling along the length of the carbon nanotube like a flame speeding along the length of a lit fuse. Heat from the fuel goes into the nanotube, where it travels thousands of times faster than in the fuel itself. As the heat feeds back to the fuel coating, a thermal wave is created that is guided along the nanotube. With a temperature of 3,000 kelvins, this ring of heat speeds along the tube 10,000 times faster than the normal spread of this chemical reaction. The heating produced by that combustion, it turns out, also pushes electrons along the tube, creating a substantial electrical current.

Combustion waves — like this pulse of heat hurtling along a wire — “have been studied mathematically for more than 100 years,” Strano says, but he was the first to predict that such waves could be guided by a nanotube or nanowire and that this wave of heat could push an electrical current along that wire.

In the group’s initial experiments, Strano says, when they wired up the carbon nanotubes with their fuel coating in order to study the reaction, “lo and behold, we were really surprised by the size of the resulting voltage peak” that propagated along the wire.

After further development, the system now puts out energy, in proportion to its weight, about 100 times greater than an equivalent weight of lithium-ion battery.

The amount of power released, he says, is much greater than that predicted by thermoelectric calculations. While many semiconductor materials can produce an electric potential when heated, through something called the Seebeck effect, that effect is very weak in carbon. “There’s something else happening here,” he says. “We call it electron entrainment, since part of the current appears to scale with wave velocity.”
The thermal wave, he explains, appears to be entraining the electrical charge carriers (either electrons or electron holes) just as an ocean wave can pick up and carry a collection of debris along the surface. This important property is responsible for the high power produced by the system, Strano says.

Exploring possible applications

Because this is such a new discovery, he says, it’s hard to predict exactly what the practical applications will be. But he suggests that one possible application would be in enabling new kinds of ultra-small electronic devices — for example, devices the size of grains of rice, perhaps with sensors or treatment devices that could be injected into the body. Or it could lead to “environmental sensors that could be scattered like dust in the air,” he says.

In theory, he says, such devices could maintain their power indefinitely until used, unlike batteries whose charges leak away gradually as they sit unused. And while the individual nanowires are tiny, Strano suggests that they could be made in large arrays to supply significant amounts of power for larger devices.

The researchers also plan to pursue another aspect of their theory: that by using different kinds of reactive materials for the coating, the wave front could oscillate, thus producing an alternating current. That would open up a variety of possibilities, Strano says, because alternating current is the basis for radio waves such as cell phone transmissions, but present energy-storage systems all produce direct current. “Our theory predicted these oscillations before we began to observe them in our data,” he says.

Also, the present versions of the system have low efficiency, because a great deal of power is being given off as heat and light. The team plans to work on improving that.

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Provided by Massachusetts Institute of Technology (http://web.mit.edu/)
Source: http://www.physorg.com/news187186888.html

Nanotechnology Shows Promise for Use in Treatments for Melanoma, other Skin Conditions

(NanoRealm) - Recent research suggests how the popular skin filler hyaluronic acid works to rejuvenate photoaged skin, and nanotechnology may have potential for use in cosmetic products and topical medical treatments, according to two presentations this week at the annual meeting of the American Academy of Dermatology, held from March 5 to 9 in Miami Beach, Fla.
In one presentation, Dana L. Sachs, M.D., of the University of Michigan in Ann Arbor, presented results of an initial study of six patients showing that hyaluronic acid injections stimulate production of type I collagen, and a subsequent study of 11 patients showing that the mechanism behind this process is increased activity of fibroblasts, which were observed at four and 13 weeks following injection to be in a 'stretched' configuration that correlates with increased collagen production.

In a second presentation, Adnan Nasir, M.D., of the University of North Carolina in Chapel Hill, discussed the pros and cons of nanotechnology and how nanoparticles may someday be used to enhance the effectiveness of cosmetic products such as sunscreens, shampoos and conditioners; anti-aging products such as retinoids, antioxidants, botulinum toxin, and growth factors; and treatments for conditions such as melanoma, atopic dermatitis, and ichthyosis. However, he cautioned that the future of nanotechnology in dermatology depends on the results of an ongoing safety review by the U.S. Food and Drug Administration.

"Research in the area of nanotechnology has increased significantly over the years, and I think there will be considerable growth in this area in the near future," Nasir said in a statement. "The challenge is that a standard has not been set yet to evaluate the safety and efficacy of topical products that contain nanosized particles."

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Source: Modern Medicine (web)
Press Release for:
1) "Research Reveals How Popular Skin Filler Works at the Molecular Level to Stimulate Collagen Production in Sun-Damaged Skin" - Sachs
2) "Sizing Up Nanotechnology: How Nanosized Particles May Affect Skin Care Products" - Nasir

(NanoRealm) - Berkeley Lab researchers have found a better way to trap light in photovoltaic cells through the use of vertical arrays of silicon nanowires. This could substantially cut the costs of solar electric power by reducing the quantity and quality of silicon needed for efficient solar panels.

Solar cells made from silicon are projected to be a prominent factor in future renewable green energy equations, but so far the promise has far exceeded the reality. While there are now silicon photovoltaics that can convert sunlight into electricity at impressive 20 percent efficiencies, the cost of this solar power is prohibitive for large-scale use. Researchers with the Lawrence Berkeley National Laboratory (Berkeley Lab), however, are developing a new approach that could substantially reduce these costs. The key to their success is a better way of trapping sunlight.



“Through the fabrication of thin films from ordered arrays of vertical silicon nanowires we’ve been able to increase the light-trapping in our solar cells by a factor of 73,” says chemist Peidong Yang, who led this research. “Since the fabrication technique behind this extraordinary light-trapping enhancement is a relatively simple and scalable aqueous chemistry process, we believe our approach represents an economically viable path toward high-efficiency, low-cost thin-film solar cells.”

Yang holds joint appointments with Berkeley Lab’s Materials Sciences Division, and the University of California Berkeley’s Chemistry Department. He is a leading authority on semiconductor nanowires - one-dimensional strips of materials whose width measures only one-thousandth that of a human hair but whose length may stretch several microns.

“Typical solar cells are made from very expensive ultrapure single crystal silicon wafers that require about 100 micrometers of thickness to absorb most of the solar light, whereas our radial geometry enables us to effectively trap light with nanowire arrays fabricated from silicon films that are only about eight micrometers thick,” he says. “Furthermore, our approach should in principle allow us to use metallurgical grade or “dirty” silicon rather than the ultrapure silicon crystals now required, which should cut costs even further.”

Yang has described this research in a paper published in the journal Nano Letters, which he co-authored with Erik Garnett, a chemist who was then a member of Yang’s research group. The paper is titled “Light Trapping in Silicon Nanowire Solar Cells.”

Generating Electricity from Sunlight

At the heart of all solar cells are two separate layers of material, one with an abundance of electrons that functions as a negative pole, and one with an abundance of electron holes (positively-charged energy spaces) that functions as a positive pole. When photons from the sun are absorbed, their energy is used to create electron-hole pairs, which are then separated at the interface between the two layers and collected as electricity.



Because of its superior photo-electronic properties, silicon remains the photovoltaic semiconductor of choice but rising demand has inflated the price of the raw material.

Furthermore, because of the high-level of crystal purification required, even the fabrication of the simplest silicon-based solar cell is a complex, energy-intensive and costly process.

Yang and his group are able to reduce both the quantity and the quality requirements for silicon by using vertical arrays of nanostructured radial p-n junctions rather than conventional planar p-n junctions. In a radial p-n junction, a layer of n-type silicon forms a shell around a p-type silicon nanowire core. As a result, photo-excited electrons and holes travel much shorter distances to electrodes, eliminating a charge-carrier bottleneck that often arises in a typical silicon solar cell. The radial geometry array also, as photocurrent and optical transmission measurements by Yang and Garrett revealed, greatly improves light trapping.

“Since each individual nanowire in the array has a p-n junction, each acts as an individual solar cell,” Yang says. “By adjusting the length of the nanowires in our arrays, we can increase their light-trapping path length.”

While the conversion efficiency of these solar nanowires was only about five to six percent, Yang says this efficiency was achieved with little effort put into surface passivation, antireflection, and other efficiency-increasing modifications.

“With further improvements, most importantly in surface passivation, we think it is possible to push the efficiency to above 10 percent,” Yang says.

Combining a 10 percent or better conversion efficiency with the greatly reduced quantities of starting silicon material and the ability to use metallurgical grade silicon, should make the use of silicon nanowires an attractive candidate for large-scale development.

As an added plus Yang says, “Our technique can be used in existing solar panel manufacturing processes.”

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Provided by: Provided by Lawrence Berkeley National Laboratory (http://www.lbl.gov/)
Source: http://www.physorg.com/news186850199.html

(NanoRealm) - Scientists in Manchester have found a clean and green way of making tiny magnets for high tech gadgets - using natural bacteria that have been around for millions of years.

The work by a team of geomicrobiologists from the University of Manchester paves the way for nanometer-size magnets - used in mobile phones and recording devices - to be made without the usual nasty chemicals and energy intensive methods.

Researchers studied iron-reducing bacteria that occur naturally in soils and sediments and found they can be used to create iron oxide nanoparticles with magnetic properties similar to those created through complex chemical processes.

Working with colleagues in Birmingham and Cardiff, the Manchester researchers also found a way of exercisising precise control over the size and magnetic strength of nanomagnets produced.
The high-tech particle accelerators at the Advanced Light Source at the famous Berkeley Labs near San Francisco, and the UK’s Diamond Light Source in Oxford at Harwell were used to verify findings.

Researchers added cobalt, manganese or nickel to the basic iron-based energy source used by bacteria, which resulted in the production of tiny magnets containing these elements. This greatly enhanced their useful magnetic properties.

Aside from being used in the latest gadgets, nanomagnets also have the potential to be used in drug delivery systems and cancer therapies to carefully focus and target the release of chemicals into the body.

Metal-reducing bacteria live in environments deficient in oxygen and react with oxidised metals to produce natural magnets in the ground beneath our feet.
And now the research team has developed a way of harnessing pure strains of these bacteria - which are in plentiful supply and reproduce quickly - to produce large quantities of nanomagnets at an ambient temperature.

This compares favourably to the extreme temperatures - as high as 1000 degrees Celsius - needed to create nanomagnets using current methods.
Prof Richard Patrick, Professor of Earth Science, said: “This is exciting work that raises the exciting prospect of a biologically friendly, energy-efficient method of producing nanomagnets tailored for different uses.”

A paper - ‘Harnessing the extracellular bacterial production of nanoscale cobalt ferrite with exploitable magnetic properties’ - outlining the research was published recently in the journal ACS Nano.

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(NanoRealm) - Malaysia’s pioneer in Nanotechnology research Professor Halimaton Hamdan is excited that things are picking up for Science and Technology in the country after a sluggish decade, writes SUZIEANA UDA NAGU

NANOTECHNOLOGY — an enabling science that has the potential for creating new knowledge and functional materials and systems — is set to shape and transform all areas of science in the future.

For example, it will revolutionise the pharmaceutical industry by changing the way drugs are produced and delivered.


Malaysia’s pioneer in Nanotechnology studies Professor Halimaton Hamdan says: “The content of a drug is less than 20 per cent of a tablet (drug carrier) — the rest are fillers and binding agents. But with Nanotechnology, we can encapsulate drugs in nanoparticles and use less binding agents.

“This requires further testing but, once proven, it will significantly improve the efficacy of drugs by reducing toxicity and increasing drug absorption, besides minimising costs.” Halimaton, who is the executive director of Enabling Science and Nanotechnology Research Alliance at Universiti Teknologi Malaysia (UTM), lists the many potentials of Nanotechnology. “It has the prospect of producing clean water supply, greater agriculture production using less labour; and cheap and powerful energy generation.

“It is also a catalyst for green — clean, renewable and non-toxic — technology,” adds Halimaton during her recent talk on The Road Map of National Nanotechnology Initiatives at Universiti Industri Selangor, Shah Alam.

Halimaton is the recipient of the Merdeka Awards 2009 in the Health, Science and Technology category. She was the first awardee to kick off the second Merdeka Awards Lecture Series this year.

Established in 2007, the Merdeka Awards recognise individuals and organisations whose works have contributed to Malaysia’s growth and inspired greatness in its people (see accompanying report).

The 53-year-old made an outstanding contribution to the field of Nanotechnology for the discovery of Maerogel — Malaysian-made aerogel — a cost-effective material made from silica in rice husks, which produces high quality insulation material that can be applied to medicine and construction, among other areas.


The research on Maerogel is groundbreaking as it has significantly lowered the cost of producing commercial aeorogel — which looks like frozen smoke.


“Traditional aerogel costs about RM15,000 per kilogramme, whereas we can produce it for only RM5,000 per kilo,” says the Physical Chemistry professor.


Halimaton Hamdan made an outstanding contribution to Nanotechnology for the discovery of Maerogel — Malaysian-made aerogel.
The discovery had also earned her Product of the Year award from Britain’s International Clean Energy Circle in 2008.




Maerogel is just one of the many ventures Halimaton had helmed in her 10-year involvement in Nanotechnology research.


In the last decade alone, Halimaton had led 25 research programmes and 80 projects.


Halimaton considers the Merdeka prize the icing on to the cake as she prepares to commercialise Maerogel, which has been patented in Malaysia and 22 other countries, this year.


“We are in the midst of setting up our first plant in Nilai, Negri Sembilan under a spin-off company of UTM,” says Halimaton, who retires in 2013.


While Halimaton has enjoyed a productive decade, Nanotechnology research and development (R&D) in Malaysia is going through a sluggish phase.


At the turn of the 21st century, Malaysia was one of the first in Asia to advance in Nanotechnology research. However, local research on the area has been making little headway since.


In 2003, the Nanotechnology Technical Committee outlined a proposal to set up Malaysia’s own National Nanotechnology programme or centre.


It was only in 2005 that Nanotechnology was included in the Ninth Malaysia Plan, followed by the launch of the National Nanotechnology Initiative in 2006.


The Initiative, among others, is to facilitate the formation of the National Nanotechnology Directorate — a central coordinating body which will drive Malaysia’s Nanotechnology policy and other R&D programmes.


“Attention on Nanotechnology died down after encouraging initial developments,” says Halimaton. Needless to say, Malaysia is currently at the bottom of the list of Asian countries which have made progress in Nanotechnology.


“If Malaysia aspires to be an advanced nation by 2020, it needs to venture into this fast-moving area of R&D to create its own products and know-how instead of being mere consumers of technology,” she adds.


But things are picking up for Science and Technology in Malaysia.


Last December, the National Innovation Council approved the setting up of the National Nanotechnology Directory, which compiles a list of Nanotechnology efforts in Malaysia.


Last month, Prime Minister Datuk Seri Najib Razak launched 2010 as the year for Innovation and Creativity in Malaysia. On top of that, the National Innovation Centre will be launched by April.


“The centre will oversee six focus areas and Nanotechnology is one of them,” says Halimaton, who also looks forward to the unveiling of the Nanotechnology Statement, which she hopes will happen soon.


The Statement comprises five core themes — promotion of Nanotechnology culture; tighter niches; enhanced networking; regulations and acts; and commercialisation and industrialisation.

“Hopefully, the Nanotechnology Statement will entice Malaysians to be a part of (the national) vision,” she adds.


Malaysia certainly stands to benefit from undertaking research efforts in Nanotechnology.


“The convergence of Nanotechnology with other fields, such as Biotechnology and Information and Communications Technology, can lead to significant economic, environmental and social opportunities and challenge,” says Halimaton.

Judging by the forward projections of the Nanotechnology market in 2014 — estimated to be worth US$2.6 trillion (RM9 trillion) — this area is a potential gold mine.


“Imagine if Malaysia captures only one per cent of the market; that is already US$26 billion!” What Malaysia needs to move forward is a well thought–out road map, which “will ensure a sustainable national development of Science and Technology”.


“We need not only political will but also a paradigm shift to succeed (in this). Scientists need to learn to work together, (despite their varied disciplines). So the onus is on the next generation to start this (interdisciplinary collaboration).


“Hopefully, this will allow Malaysia to compete with the best in the world on its own terms — by focusing on its strengths such as in Nanobiomedicine,” she adds.

Raise awareness with cartoons

LOCAL tertiary institutions are not be ready to offer degrees in Nanotechnology as there is no market for such graduates in the industry.

Malaysia’s pioneer in Nanotechnology studies Professor Halimaton Hamdan says: “It will be possible once industry has fully engaged in Nanotechnology.”

Halimaton, also executive director of Enabling Science and Nanotechnology Research Alliance at Universiti Teknologi Malaysia (UTM), is the recipient of the Merdeka Awards 2009 in the Health, Science and Technology category.

The Professor of Physical Chemistry received her first degree in Chemistry from the United States’ Indiana University in Bloomington in 1979.

Upon graduating with a Master’s in Chemistry from Marshall University, Huntington in West Virginia, in 1981, Halimaton returned home to teach at UTM.

Four years later, she had the chance to pursue her doctorate in Physical
Chemistry at the University of Cambridge, the United Kingdom. It was at Cambridge that Halimaton developed an interest in Nanotechnology.

Awareness campaigns are crucial if local industries want to engage in nanotechnology.

“Everyone must know what Nanotechnology is about. Many still doubt the technology — whether or not it poses any health risks, for example,” she says.

Developing countries have been criticised for not taking into consideration public concerns over the use of Nanotechnology in manufacturing products, unlike in the West where awareness campaigns involve even preschool children.

“In Taiwan and the United States, cartoons are used to introduce the concept of Nanotechnology to kids,” says Halimaton, adding that Malaysia should do the same.

To pursue careers in Nanotechnology, students should pay attention to Science subjects.

“Identify which branch of Science — Physics, Chemistry or Biology — is your strength,” she adds.

Next week: UTM vice chancellor Professor Datuk Zaini Ujang, a recipient of the Merdeka Awards 2009 for Outstanding Scholastic Achievement

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Source: NST Online - http://www.nst.com.my/Current_News/NST/articles/20100227215953/Article/index_html

(NanoRealm) - Researchers at Tyndall National Institute in Cork, Ireland led by professor Jean-Pierre Colinge have reported in Nature Nanotechnology how they have designed and fabricated what is claimed to be the first junctionless transistor, which could significantly reduce power consumption and simplify the fabrication process for silicon chips, it is reckoned.

Existing transistors are based on junctions formed by adjacent layers of semiconductor material with different dopant-atom-induced polarities. Since controlling the junction allows current in the device to be turned on and off, it is the precise fabrication of this junction that determines the characteristics and quality of the transistor and is a major factor in production costs. However, as the distance between junctions drops below 10nm, extraordinarily high doping concentration gradients become necessary. Because of the laws of diffusion and the statistical nature of the distribution of the doping atoms, such junctions require increasingly complex and costly fabrication processes.

Tyndall’s new transistor consists of a silicon nanowire (about 30nm across just 10nm thick), and it has no junctions and no doping concentration gradients, since current flow is controlled by a ‘wedding ring’ gate structure around the wire. “These structures are easy to fabricate even on a miniature scale, which leads to the major breakthrough in potential cost reduction,” claims Colinge.

Another key challenge for the semiconductor industry is reducing the power consumption of complex transistors, with minimizing current leakage one of the main challenges. The new transistors — which can be made to have full CMOS functionality — have near-ideal subthreshold slope, extremely low leakage currents, and less degradation of mobility with gate voltage and temperature than classical transistors, Tyndall claims. “They have the potential of operating faster and using less energy than the conventional transistors used in today’s microprocessors,” says Colinge.

The junctionless transistor resembles the first ideal transistor structure, proposed in 1925, but to-date no-one had been able to fabricate it, continues Colinge. He attributes Tyndall’s junctionless transistor to the ability to fabricate a silicon nanowire with a diameter of just a few dozen atoms using electron-beam writing techniques and commercial silicon-on-insulator (SOI) wafers.

“We are beginning to talk about these results with some of the world’s leading semiconductor companies, and are receiving a lot of interest in further development and possible licensing of the technology,” says Tyndall’s CEO, professor Roger Whatmore.

The work was funded by Science Foundation Ireland, and is also underpinned by substantial investments in Tyndall by the Department of Enterprise Trade and Employment and the Higher Education Authority, comments Whatmore.

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Source: Semiconductor today - http://www.semiconductor-today.com/news_items/2010/MARCH/TYNDALL_010310.htm

Visit: www.nature.com

Visit: www.tyndall.ie/control

(NanoRealm) - Iranian Engineers suggested a new method for lining internal surfaces of pipes, steel and aluminum tubes and bars to fight against common erosions and corrosions.

"First, the surface of aluminum metal was coated by nickel through mechanical alloying (MA) method. To do so, nickel powder together with aluminum samples of cubic form were ball-milled in a planetary ball-mill for various durations and different amounts of the powder.

Such different operational conditions led triggered chemical/diffusional interactions, alloying and formation of new intermetallic phases," Rasoul Pouriamanesh, a member of the research team at Ferdowsi University of Mashhad (FUM) said to the Iran Nanotechnology Initiative Council, elaborating on the steps of the research.

Noting that intermetallic phases like Ni-Al, Al3Ni and Ni3Al were formed inside the coating layer, Pouriamanesh reiterated that it was revealed that the reactions involved (all of which are exothermic) caused local temperature increases and promoted a better cling of layer to target at the spots where the reactions occurred.

"The coating layers were consisted of nanoparticles with different size distributions. After annealing, the microstructures and sizes of the particles were investigated to find the optimal conditions for obtaining perfect coated metal surfaces," he added.

Pouriamanesh referred to "achieving a homogeneous, poreless and uniform nanostructure inside the coating layer (which facilitates metal diffusions and formation of intermetallic phases of Al-Ni" as the outcome of the research.

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Source: FarNews - http://english.farsnews.com/newstext.php?nn=8812030880

(NanoRealm) - When nanoparticles from consumer products leach into the ocean, they may harm oysters and mussels.

Nanoparticles May Harm Ocean Living Creatures

Manufactured nanomaterials can be found in such diverse applications as electronics, cosmetics, paints, and even medicines, but their effects on the environment remain largely unknown. In a new laboratory study, scientists have found that saltwater oysters and mussels take up and retain significant amounts of manufactured nanoparticles from seawater in clumps of so-called “marine snow.”

“Nanomaterials are being used in increasing amounts, and it’s likely they’re being released in increasing amounts into the environment, including the ocean,” says Evan Ward, professor of marine sciences at UConn’s Avery Point campus. “As we develop these technologies, we need to be cautious, we need to know where the particles are going, and we need to know how they affect marine organisms.”

Nanoparticles are tiny versions of common materials that have a diameter of less than 100 nanometers, or about four millionths of an inch. Their tininess gives them properties that normal-sized particles don’t have: for example, their large surface area for their size makes them stronger, lighter, and more reflective, making them ideal for reinforcing metals, increasing the SPF in your sunscreen, and producing paint that improves your home’s energy efficiency.
Some scientists, however, are concerned that these very properties could also make manufactured nanoparticles dangerous. When products break down in landfills, nanoparticles can wash away into soils, waterways, and the ocean, potentially creating hazards to animals and plants.
“Some materials that one would assume are safe can in fact cause damage to cells in their ‘nano’ form,” Ward says.

Ward studies the environmental physiology of oysters, mussels, and their relatives, which use their gills as specialized filters to take up food from ocean water. Although nanoparticles themselves are too small to be captured in large amounts, Ward’s study focused on how the bivalves’ feeding ecology affected their rate of uptake.

“In our study, we took into account how nanoparticles are likely to be delivered to the animals in the natural environment,” he says. “We asked, ‘What’s the setting in which they will be exposed to these particles?’”

Materials rarely exist as individual particles in the ocean, says Ward; instead, ocean currents bind up particles and sticky organic matter into aggregates that scientists call “marine snow.” These aggregates then sink to the bottom, where filter feeders like bivalves ingest them.

In their paper, published in Marine Environmental Research, Ward and coauthor Dustin Kach, a former UConn graduate student, used natural seawater to produce marine snow that contained fluorescently labeled polystyrene nanoparticles. They then exposed oysters and mussels collected from the Long Island Sound to this snow-filled seawater.

The researchers found that nanoparticles were taken up in much higher amounts when the bivalves were exposed to marine snow. But they also found that when filtered from marine snow, nanoparticles remained in the bivalves’ bodies for a much longer time than would be expected for non-nutritive materials: up to three days.

Ward suspects that the particles are being treated as food by the animals, and are being taken up into their digestive cells. This could be particularly dangerous, he says, since small nanoparticles can circumvent living cells’ natural defenses.

“Because of their high surface area, manufactured nanoparticles can strip off electrons from other compounds and create free radicals,” he says. “Particles like these can cause havoc in cells.”
Ward sees his work as a first step in understanding the potential issues associated with manufactured nanoparticles. He emphasizes that further work is needed to determine the amounts of manufactured nanoparticles in seawater and their levels of toxicity to living things.

“Right now there are few techniques to identify manufactured nanomaterials in the natural environment because they’re so darn small,” he says. “With these studies, we hope to demonstrate potential problems to keep in step with the use of nanomaterials. Then when techniques are available to sample them in the wild, we’ll be prepared to say whether or not we should be worried.”

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More information: http://www.elsevier.com/wps/find/journaldescription.cws_home/405865/description#description
Provided by University of Connecticut (web)

Source: http://www.physorg.com/news186058984.html

Stanford researcher Yi Cui and his team are re-conceptualizing batteries using nanotechnology

(NanoRealm) - By dipping ordinary paper or fabric in a special ink infused with nanoparticles, Stanford engineer Yi Cui has found a way to cheaply and efficiently manufacture lightweight paper batteries and supercapacitors (which, like batteries, store energy, but by electrostatic rather than chemical means), as well as stretchable, conductive textiles known as "eTextiles" – capable of storing energy while retaining the mechanical properties of ordinary paper or fabric.

While the technology is still new, Cui's team has envisioned numerous functional uses for their inventions. Homes of the future could one day be lined with energy-storing wallpaper. Gadget lovers would be able to charge their portable appliances on the go, simply plugging them into an outlet woven into their T-shirts. Energy textiles might also be used to create moving-display apparel, reactive high-performance sportswear and wearable power for a soldier's battle gear.

The key ingredients in developing these high-tech products are not visible to the human eye. Nanostructures, which can be assembled in patterns that allow them to transport electricity, may provide the solutions to a number of problems encountered with electrical storage devices currently available on the market.

The type of nanoparticle used in the Cui group's experimental devices varies according to the intended function of the product – lithium cobalt oxide is a common compound used for batteries, while single-walled carbon nanotubes, or SWNTs, are used for supercapacitors.

Cui, an assistant professor of materials science and engineering at Stanford, leads a research group that investigates new applications of nanoscale materials. The objective, said Cui, is not only to supply answers to theoretical inquiries but also to pursue projects with practical value. Recently, his team has focused on ways to integrate nanotechnology into the realm of energy development.

"Energy storage is a pretty old research field," said Cui. "Supercapacitors, batteries – those things are old. How do you really make a revolutionary impact in this field? It requires quite a dramatic difference of thinking."

While electrical energy storage devices have come a long way since Alessandro Volta debuted the world's first electrical cell in 1800, the technology is facing yet another revolution. Current methods of manufacturing energy storage devices can be capital intensive and environmentally hazardous, and the end products have noticeable performance constraints – conventional lithium ion batteries have a limited storage capacity and are costly to manufacture, while traditional capacitors provide high power but at the expense of energy storage capacity.


With a little help from new science, the batteries of the future may not look anything like the bulky metal units we've grown accustomed to. Nanotechnology is favored as a remedy both for its economic appeal and its capability to improve energy performance in devices that integrate it. Replacing the carbon (graphite) anodes found in lithium ion batteries with anodes of silicon nanowires, for example, has the potential to increase their storage capacity by 10 times, according to experiments conducted by Cui's team.

Silicon had previously been recognized as a favorable anode material because it can hold a larger amount of lithium than carbon. But applications of silicon were limited by its inability to sustain physical stress – namely, the fourfold volume increase that silicon undergoes when lithium ions attach themselves to a silicon anode in the process of charging a battery, as well as the shrinkage that occurs when lithium ions are drawn out as it discharges. The result was that silicon structures would disintegrate, causing anodes of this material to lose much if not all of their storage capacity.

Cui and collaborators demonstrated in previous publications in Nature, Nanotechnology and Nano Letters that the use of silicon nanowire battery electrodes, mechanically capable of withstanding the absorption and discharge of lithium ions, was one way to sidestep the problem.

The findings hold promise for the development of rechargeable lithium batteries offering a longer life cycle and higher energy capacity than their contemporaries. Silicon nanowire technology may one day find a home in electric cars, portable electronic devices and implantable medical appliances.

Cui now hopes to direct his research toward studying both the "hard science" behind the electrical properties of nanomaterials and designing real-world applications.

"This is the right time to really see what we learn from nanoscience and do practical applications that are extremely promising," said Cui. "The beauty of this is, it combines the lowest cost technology that you can find to the highest tech nanotechnology to produce something great. I think this is a very exciting idea … a huge impact for society."

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The Cui group's latest research on energy storage devices was detailed in papers published in the online editions of the Proceedings of the National Academy of Sciences in December 2009 ("Highly Conductive Paper for Energy-Storage Devices") and Nano Letters in January 2010 ("Stretchable, Porous and Conductive Energy Textiles").

Cui's talk at the symposium "Nanotechnology: Will Nanomaterials Revolutionize Energy Applications?" is scheduled for 9:50 a.m. Feb. 20 in Room 1B of the San Diego Convention Center.

Video/photos:
Conductive eTextiles: Stanford finds a new use for cloth
http://news.stanford.edu/news/2010/february1/batteries-from-cloth-020510.html

At Stanford, nanotubes + ink + paper = instant battery
http://news.stanford.edu/news/2009/december7/nanotubes-ink-paper-120709.html

Source: http://www.eurekalert.org/pub_releases/2010-02/su-nse021910.php