September 23, 2009, 7:09 AM CT

Diamonds may be the ultimate MRI probe

Diamonds, it has long been said, are a girl's best friend. But a research team including a physicist from the National Institute of Standards and Technology (NIST) has recently found* that the gems might turn out to be a patient's best friend as well.

The team's work has the long-term goal of developing quantum computers, but it has borne fruit that may have more immediate application in medical science. Their finding that a candidate "quantum bit" has great sensitivity to magnetic fields hints that MRI-like devices that can probe individual drug molecules and living cells appears to be possible.

The candidate system, formed from a nitrogen atom lodged within a diamond crystal, is promising not only because it can sense atomic-scale variations in magnetism, but also because it functions at room temperature. Most other such devices used either in quantum computation or for magnetic sensing must be cooled to nearly absolute zero to operate, making it difficult to place them near live tissue. However, using the nitrogen as a sensor or switch could sidestep that limitation.

Diamond, which is formed of pure carbon, occasionally has minute imperfections within its crystalline lattice. A common impurity is a "nitrogen vacancy", in which two carbon atoms are replaced by a single atom of nitrogen, leaving the other carbon atom's space vacant. Nitrogen vacancies are in part responsible for diamond's famed luster, for they are actually fluorescent: when green light strikes them, the nitrogen atom's two excitable unpaired electrons glow a brilliant red......... Posted by: Kevin      Read more         Source

September 15, 2009, 2:48 PM CT

Sorting and assembling nanotubes

Nanotubes and nanowires are promising building blocks for future integrated nanoelectronic and photonic circuits, nanosensors, interconnects and electro-mechanical nanodevices. But some fundamental issues remain to be resolved among them, how to position and manipulate the tiny tubes.

Publishing in the journal Nature Materials this week, scientists from four different institutions report measuring different friction forces when a carbon nanotube slides along its axis in comparison to when it slides perpendicular to its axis. This friction difference has its origins in soft lateral distortion of the tubes when they slide in the transverse direction.

The findings not only could provide a better understanding of fundamental friction issues, but from a more practical standpoint, offer a new tool for assembling nanotubes into devices and clarify the forces acting on them. Asymmetries in the friction could potentially also be used in sorting nanotubes as per their chirality, a property that is now difficult to measure with other means.

When an atomic force microscope (AFM) tip is scanned transversely across a multi-walled carbon nanotube, the amount of friction measured is twice as much as when the same tube is scanned longitudinally, along the length of the tube. The scientists attribute this difference to what they call "hindered rolling" additional effort mandatory to overcome the nanotube's tendency to roll as the AFM tip strokes across it rather than along it......... Posted by: Kevin      Read more         Source

September 15, 2009, 7:57 AM CT

Seal of quality for hygienic equipment

The processing and packaging of food is governed by very strict hygiene rules. Scientists are now testing production equipment for cleanroom suitability and are listing qualified products in an online database.

Before entering the cleanroom, the researcher dons special protective clothing to avoid carrying germs or other impurities into the highly sensitive environment. But it's not only people who have to conform to the strict hygiene requirements. Every item of equipment in the room, from lithography units to swivel chairs, must also comply with international guidelines.

Equipment manufacturers can have their products inspected and certified at the Fraunhofer Institute for Manufacturing Engineering and Automation IPA in Stuttgart. "This service was initially aimed at the semiconductor industry, but it is now attracting a number of customers from other sectors such as pharmacy or the food-processing industry, where hygiene standards are very high," says Markus Keller. In the cleanroom manufacturing and microfabrication department he tests equipment for its cleanroom suitability - from wall and floor coverings to tools right through to complete interiors. "To find out, for example, whether a surface can be easily disinfected we examine its surface finish under the microscope - the smoother, the better. The material must also be resistant to attack by certain chemicals," explains Keller. He also examines the design and assembly of furniture extremely closely - are there any inaccessible corners where dirt could settle? Are there any screws which are not tightened correctly? Badly designed pipe connections - including screw connections - could result in fat or protein residues being pressed into tiny hollow spaces, which at first sight are not visible at all - the best conditions for germs. The researchers must also measure whether materials emit particles or release gases at high temperatures. "Our testing devices are so precise that we can detect particle emissions in the sub-micrometer region," says Keller......... Posted by: Kevin      Read more         Source

September 10, 2009, 6:51 AM CT

New robot travels across the seafloor

Like the robotic rovers Spirit and Opportunity, which wheeled tirelessly across the dusty surface of Mars, a new robot spent most of July traveling across the muddy ocean bottom, about 40 kilometers (25 miles) off the California coast. This robot, the Benthic Rover, has been providing researchers with an entirely new view of life on the deep seafloor. It will also give researchers a way to document the effects of climate change on the deep sea. The Rover is the result of four years of hard work by a team of engineers and researchers led by MBARI project engineer Alana Sherman and marine biologist Ken Smith.

About the size and weight of a small compact car, the Benthic Rover moves very slowly across the seafloor, taking photographs of the animals and sediment in its path. Every three to five meters (10 to 16 feet) the Rover stops and makes a series of measurements on the community of organisms living in the seafloor sediment. These measurements will help researchers understand one of the ongoing mysteries of the ocean-how animals on the deep seafloor find enough food to survive.

Most life in the deep sea feeds on particles of organic debris, known as marine snow, which drift slowly down from the sunlit surface layers of the ocean. But even after decades of research, marine biologists have not been able to figure out how the small amount of nutrition in marine snow can support the large numbers of organisms that live on and in seafloor sediment......... Posted by: Kevin      Read more         Source

September 9, 2009, 7:29 AM CT

Light at the speed of a bicycle and much more

The speed of light, 300 million metres per second, was long thought an immutable constant and has defined our understanding of matter and energy but recent research in the area of optics and photonics is proving that we can manipulate light to some ingenious and hugely lucrative ends.

From the use of adaptive optics to catch perfect images of distant galaxies or detailed representations inside bio-specimens of, for example, mouse embryos, to electromagnetically induced transparency which can slow light to the speed of a bicycle - the field of optics and photonics is in the scientific vanguard.

The Institute of Physics (IOP) and the Engineering and Physical Sciences Research Council (EPSRC) are launching a new report today, Wednesday, 9 September, entitled Optics and photonics: Physics enhancing our lives, to highlight the most recent advances in the field and demonstrate the potentially lucrative ends a range of scientists have in sight.

This field of research has already had a revolutionary effect on all of our everyday lives. From optical fibres, hair-like strands of silica glass that transmit vast amounts of data around the world as fleeting pulses of light, to lasers built in to our CD and DVD players, much of the developed world's technological infrastructure is already structured on physicists' ability to play with light......... Posted by: Kevin      Read more         Source

August 28, 2009, 6:49 AM CT

Neural Nanoblockers in Carbon Nanotubes

Carbon nanotubes hold a number of exciting possibilities, some of them in the realm of the human nervous system. Recent research has shown that carbon nanotubes may help regrow nerve tissue or ferry drugs used to repair damaged neurons linked to disorders such as epilepsy, Parkinson's disease and perhaps even paralysis.

Yet some studies have shown that carbon nanotubes appear to interfere with a critical signaling transaction in neurons, throwing doubt on the tubes' value in treating neurological disorders. No one knew why the tubes were causing a problem.

Now a team of Brown University scientists has observed that it's not the tubes that are to blame. Writing in the journal Biomaterials, the researchers report that the metal catalysts used to form the tubes are the culprits, and that minute amounts of one metal - yttrium - could impede neuronal activity. The findings mean that carbon nanotubes without metal catalysts appears to be able to treat human neurological disorders, eventhough other possible biological effects still need to be studied.

Lorin Jakubek.

"It's a problem we can fix." "We can purify the nanotubes by removing the metals," said Lorin Jakubek, a Ph.D. candidate in biomedical engineering and main author of the paper, "so, it's a problem we can fix"......... Posted by: Kevin      Read more         Source

August 26, 2009, 11:07 PM CT

Who are you?

A new publication that recommends best practices for the next generation of portable biometric acquisition devicesMobile IDhas been published by the National Institute of Standards and Technology (NIST).

Devices that gather, process and transmit an individuals biometric datafingerprints, facial and iris imagesfor identification are proliferating. Prior work on standards for these biometric devices has focused primarily on getting different stationary and desktop systems with hardwired processing pathways to work together in an interoperable manner. But a new generation of small, portable and versatile biometric devices are raising new issues for interoperability.

The proliferation of smaller devices including advanced personal digital assistants (PDAs), ultra-portable personal computers and high-speed cellular networks has made portable biometric systems a reality, computer scientist Shahram Orandi says. While the portable systems have made leaps and bounds in terms of capability, there are still intrinsic limitations that must be factored into the big picture to ensure interoperability with the larger, more established environments such as desktop or large server-based systems.

The new mobile biometric devices allow first responders, police, the military and criminal justice organizations to collect biometric data with a handheld device on a street corner or in a remote area and then wirelessly send it to be in comparison to other samples on watch lists and databases in near real-time. Identities can be determined quickly without having to take a subject to a central facility to collect his or her biometrics, which is not always possible......... Posted by: Kevin      Read more         Source

August 26, 2009, 7:03 AM CT

What happens on nanoscale

Johns Hopkins engineers are using a popular children's toy to visualize the behavior of particles, cells and molecules in environments too small to see with the naked eye. These scientists are arranging little LEGO pieces shaped like pegs to re-create microscopic activity taking place inside lab-on-a-chip devices at a scale they can more easily observe.

These lab-on-a-chip devices, also known as microfluidic arrays, are usually used to sort tiny samples by size, shape or composition, but the minuscule forces at work at such a small magnitude are difficult to measure. To solve this small problem, the Johns Hopkins engineers decided to think big.

Led by Joelle Frechette and German Drazer, both assistant professors of chemical and biomolecular engineering in the university's Whiting School of Engineering, the team used beads just a few millimeters in diameter, an aquarium filled with goopy glycerol and the LEGO pieces arranged on a LEGO board to unlock mysteries occurring at the micro- or nanoscale level. Their observations could offer clues on how to improve the design and fabrication of lab-on-a-chip technology. Their study concerning this technique was reported in the Aug. 14 issue of Physical Review Letters.

The idea for this project comes from the concept of "dimensional analysis," in which a process is studied at a different size and time scale while keeping the governing principles the same......... Posted by: Kevin      Read more         Source

August 24, 2009, 10:33 PM CT

Lower-cost solar cells to be printed like newspaper

Solar cells could soon be produced more cheaply using nanoparticle "inks" that allow them to be printed like newspaper or painted onto the sides of buildings or rooftops to absorb electricity-producing sunlight.

Brian Korgel, a University of Texas at Austin chemical engineer, is hoping to cut costs to one-tenth of their current price by replacing the standard manufacturing process for solar cells - gas-phase deposition in a vacuum chamber, which requires high temperatures and is relatively expensive.

"That's essentially what's needed to make solar-cell technology and photovoltaics widely adopted," Korgel said. "The sun provides a nearly unlimited energy resource, but existing solar energy harvesting technologies are prohibitively expensive and cannot compete with fossil fuels".

For the past two years, Korgel and his team have been working on this low-cost, nanomaterials solution to photovoltaics - or solar cell - manufacturing. Korgel is collaborating with professors Al Bard and Paul Barbara, both of the Department of Chemistry and Biochemistry, and Professor Ananth Dodabalapur of the Electrical and Computer Engineering Department. They recently showed proof-of-concept in a recent issue of Journal of the American Chemical Society.

The inks could be printed on a roll-to-roll printing process on a plastic substrate or stainless steel. And the prospect of being able to paint the "inks" onto a rooftop or building is not far-fetched......... Posted by: Kevin      Read more         Source

August 20, 2009, 6:50 AM CT

Flying by the Skin of Our Teeth

It's been a mystery: how can our teeth withstand such an enormous amount of pressure, over a number of years, when tooth enamel is only about as strong as glass? A newly released study by Prof. Herzl Chai of Tel Aviv University's School of Mechanical Engineering and colleagues at the National Institute of Standards and Technology and George Washington University gives the answer.

The scientists applied varying degrees of mechanical pressure to hundreds of extracted teeth, and studied what occurred on the surface and deep inside them. The study, reported in the May 5, 2009, issue of the Proceedings of the National Academy of Science, shows that it is the highly-sophisticated structure of our teeth that keeps them in one piece - and that structure holds promising clues for aerospace engineers as they build the aircraft and space vehicles of the future.

"Teeth are made from an extremely sophisticated composite material which reacts in an extraordinary way under pressure," says Prof. Chai. "Teeth exhibit graded mechanical properties and a cathedral-like geometry, and over time they develop a network of micro-cracks which help diffuse stress. This, and the tooth's built-in ability to heal the micro-cracks over time, prevents it from fracturing into large pieces when we eat hard food, like nuts"......... Posted by: Kevin      Read more         Source