By cleverly linking five Wii Balance Boards, a team of Rice University undergraduates has combined the appeal of a video game with the utility of a computerized motion-tracking system that can enhance the progress of patients at Shriners Hospital for Children-Houston.

The Rice engineering students created the new device using components of the popular Nintendo game system to create a balance training system.

Custom sensors built by Rice engineering students are part of the active handrails that provide force feedback on how heavily patients are depending on their arms as they perform balancing tasks on the Wii boards. Credit: Jeff Fitlow/Rice University

What the kids may see as a fun video game is really a sophisticated way to help them advance their skills. The Wii Balance Boards lined up between handrails will encourage patients age 6 to 18 to practice their balance skills in an electronic gaming environment. The active handrails, which provide feedback on how heavily patients depend on their arms, are a unique feature.

Many of the children targeted for this project have cerebral palsy, spina bifida or amputations. Using the relatively inexpensive game console components improves the potential of this system to become a cost-effective addition to physical therapy departments in the future.

Steven Irby, an engineer at Shriners' Motion Analysis Laboratory, pitched the idea to Rice's engineering mentors after the success of last year's Trek Tracker project, a computer-controlled camera system for gait analysis that was developed by engineering students at Rice's Oshman Engineering Design Kitchen (OEDK).

The engineering seniors who chose to tackle this year's new project -- Michelle Pyle, Drew Berger and Matt Jones, aka Team Equiliberators -- hope to have the system up and running at Shriners Hospital before they graduate next month.

"He (Irby) wants to get kids to practice certain tasks in their games, such as standing still, then taking a couple of steps and being able to balance, which is pretty difficult for some of them," Pyle said. "The last task is being able to take a couple of steps and then turn around."

"This isn't a measurement device as much as it is a game," Irby said. "But putting the two systems together is what makes it unique. The Wii system is not well suited to kids with significant balance problems; they can't play it. So we're making something that is more adaptable to them."

The game requires patients to shoot approaching monsters by hitting particular spots with their feet as they step along the Wii array, computer science student Jesus Cortez, one of the game's creators, explained. The game gets harder as the patients improve, he said, and the chance to rack up points gives them an incentive.

A further step, not yet implemented, would be to program feedback from the handrails into the game. Leaning on the rails would subtract points from the users' scores, encouraging them to improve their postures. The game would also present challenges specific to younger and older children to keep them engaged.

The programming team also includes undergraduate Irina Patrikeeva and graduate student Nick Zhu. Studio arts undergraduate Jennifer Humphreys created the artwork.

Team Equiliberator combines engineering, computer science and art students in a project that uses Wii Balance Boards, a handrail sensor system and custom game software to help patients at Shriners Hospital for Children-Houston develop their balance. Clockwise from left: Matt Jones, Drew Berger, Jesus Cortez, Nick Zhu, Irina Patrikeeva, Michelle Pyle and Jennifer Humphreys. Credit: Jeff Fitlow/Rice University

The system's components include a PC, the Wii boards (aligned in a frame) and two balance beam-like handrails that read how much force patients are putting on their hands. Communications to the PC are handled via the Wii's native Bluetooth protocol.

The students said their prototype cost far less than the $2,000 they'd budgeted. Rice supplied the computer equipment and LabVIEW software they needed to create the diagnostic software that interfaces with Shriners' existing systems, and they purchased the Wii Balance Boards on eBay.

"Small force plates that people commonly use for such measurements cost at least a couple of grand, but Wii boards -- and people have done research on this -- give you a pretty good readout of your center of balance for what they cost," Pyle said.

Jones, who is building the final unit for delivery to Shriners, said he wants patients to see the Wii boards. "We're putting clear acrylic over the boards so there aren't any gaps that could trip up the younger ones," he said. "We wanted to use a device that's familiar to them, but they might not be convinced it's a Wii board unless they can see it."

Source: physorg - Research provided by Rice University

If your asthma is acting up, you’re probably not the only one. But unless you’re standing next to someone who is also huffing his or her inhaler, you wouldn’t know it. That’s a problem for epidemiologists who do their best work when they’re buried in data, and it’s exactly the problem a former Centers for Disease Control and Prevention (CDC) researcher aims to solve with a GPS- and WiFi-enabled inhaler.

The Ubiquitous Inhaler is Getting a Digital Upgrade - Mendel via Wikimedia

Asthma attacks can happen anywhere, but the causes of these attacks can be hard to pin down because patients don’t always report, or even remember, every time they pop their inhaler out for some respiratory relief. Dr. David Van Sickle’s Spiroscout inhaler aims to change this. Suck on the Spiroscout and it logs the time and position, sending it to a central computer for analysis.

That analysis benefits asthma sufferers on two levels. Individually, it allows participating patients and their doctors to analyze their inhaler use, shedding light on patterns that may develop in inhaler usage or indicating that perhaps the patient needs an adjustment in his or her medication.

But the larger benefit is societal. Once the data is stripped of identifying information, epidemiologists can analyze trends among entire groups of asthma sufferers. From this, they should be able to identify certain environmental and geographical factors--areas where certain plants are present or where certain pollutants are peristent--that precipitate asthma attacks. That could lead not only to a better understanding of asthma, but to a better understanding of the general air quality in a given area.

Source: PopSci

A report, published in the March 14 edition of the Journal of Materials Chemistry, announced the successful fabrication and testing of a new type solar cell using an inorganic core/shell nanowire structure.
Arrays of core/shell nanowires (described has "quantum coaxial cables") had previously been theorized as a potential structure that, while composed of chemically more stable large bandgap inorganic materials, should also be capable of absorbing the broad range of the wavelengths present in sunlight. High bandgap semiconductors are generally considered not effective at absorbing most of the available wavelengths in solar radiation by themselves. For instance, high bandgap zinc oxide (ZnO) is transparent in the visible but absorptive in the ultraviolet range, and thus is widely used in sunscreens but was not considered useful in solar cells.

In the report, a team of researchers from Xiamen University in China and the University of North Carolina at Charlotte describe successfully creating zinc oxide (ZnO) nanowires with a zinc selenide (ZnSe) coating to form a material structure known as a type-II heterojunction that has a significantly lower bandgap than either of the original materials. The team reported that arrays of the structured nanowires were subsequently able to absorb light from the visible and near-infrared wavelengths, and show the potential use of wide bandgap materials for a new kind of affordable and durable solar cell.
"High bandgap materials tend to be chemically more stable than the lower bandgap semiconductors that we currently have," noted team member Yong Zhang, a Bissell Distinguished Professor in the Department of Electrical and Computer Engineering and in the Energy Production and Infrastructure Center (EPIC) at the University of North Carolina at Charlotte.

"And these nanowire structures can be made using a very low cost technology, using a chemical vapor deposition (CVD) technique to grow the array," he added. "In comparison, solar cells using silicon and gallium arsenide require more expensive production techniques."
Based on a concept published in Nano Letters in 2007 by Zhang and collaborators Lin-Wang Wang (Lawrence Berkeley National Laboratory) and Angelo Mascarenhas (National Renewable Energy Laboratory), the array was fabricated by Zhang's current collaborators Zhiming Wu, Jinjian Zheng, Xiangan Lin, Xiaohang Chen, Binwang Huang, Huiqiong Wang, Kai Huang, Shuping Li and Junyong Kang at the Fujian Key Laboratory of Semiconductor Materials and Applications in the Department of Physics at Xiamen University, China.

Past attempts to use high band gap materials did not actually use the semiconductors to absorb light but instead involved coating them with organic molecules (dyes) that accomplished the photo absorption and simply transmitted electrons to the semiconductor material. In contrast, the team's heterojunction nanowires absorb the light directly and efficiently conduct a current through nano-sized "coaxial" wires, which separate charges by putting the excited electrons in the wires' zinc oxide cores and the "holes" in the zinc selenide shells.
"By making a special heterojunction architecture at the nanoscale, we are also making coaxial nanowires which are good for conductivity," said Zhang. "Even if you have good light absorption and you are creating electron-hole pairs, you need to be able to take them out to the circuit to get current, so we need to have good conductivity. These coaxial nanowires are similar to the coaxial cable in electrical engineering. So basically we have two conducting channels -- the electron going one way in the core and the hole going the other way in the shell."

The nanowires were created by first growing an array of six-sided zinc oxide crystal "wires" from a thin film of the same material using vapor deposition. The technique created a forest of smooth-sided needle-like zinc oxide crystals with uniform diameters (40 to 80 nanometers) along their length (approximately 1.4 micrometers). A somewhat rougher zinc selenide shell was then deposited to coat all the wires. Finally, an indium tin oxide (ITO) film was bonded to the zinc selenide coating, and an indium probe was connected to the zinc oxide film, creating contacts for any current generated by the cell.
"We measured the device and showed the photoresponse threshold to be 1.6 eV," Zhang said, noting that the cell was thus effective at absorbing light wave wavelengths from the ultraviolet to the near infrared, a range that covers most of the solar radiation reaching earth's surface.

Though the use of the nanowires for absorbing light energy is an important innovation, perhaps even more important is the researchers' success in using stable high bandgap inorganic semiconductor materials for an inexpensive but effective solar energy device.

"This is a new mechanism, since these materials were previously not considered directly useful for solar cells," Zhang said. He stressed that the applications for the concept do not end there but open the door to considering a larger number of high bandgap semiconductor materials with very desirable material properties for various solar energy related applications, such as hydrogen generation by photoelectrochemical water splitting.
"The expanded use of type II nanoscale heterostructures also extends their use for other applications as well, such as photodetectors -- IR detector in particular," he noted.
 
Source: ScienceDaily

Producing hydrogen in a sustainable way is a challenge and production cost is too high. A team led by EPFL Professor Xile Hu has discovered that a molybdenum based catalyst is produced at room temperature, inexpensive and efficient. The results of the research are published online in Chemical Science Thursday the 14th of April. An international patent based on this discovery has just been filled.

Existing in large quantities on Earth, water is composed of hydrogen and oxygen. It can be broken down by applying an electrical current; this is the process known as electrolysis. To improve this particularly slow reaction, platinum is generally used as a catalyst. However, platinum is a particularly expensive material that has tripled in price over the last decade. Now EPFL scientists have shown that amorphous molybdenum sulphides, found abundantly, are efficient catalysts and hydrogen production cost can be significantly lowered.

Industrial prospects

The new catalysts exhibit many advantageous technical characteristics. They are stable and compatible with acidic, neutral or basic conditions in water. Also, the rate of the hydrogen production is faster than other catalysts of the same price. The discovery opens up some interesting possibilities for industrial applications such as in the area of solar energy storage.

Using a molybdenum based catalyst, hydrogen bubbles are made cheaply and at room temperature. Credit: EPFL / Alain Herzog

It's only by chance that Daniel Merki, Stéphane Fierro, Heron Vrubel and Xile Hu made this discovery during an electrochemical experience. "It's a perfect illustration of the famous serendipity principle in fundamental research", as Xile Hu emphasizes: "Thanks to this unexpected result, we've revealed a unique phenomenon", he explains. "But we don't yet know exactly why the catalysts are so efficient."

The next stage is to create a prototype that can help to improve sunlight-driven hydrogen production. But a better understanding of the observed phenomenon is also required in order to optimize the catalysts.
 
Source: PhysOrg

More information: Daniel Merki, Stéphane Fierro, Heron Vrubel and Xile Hu, "Amorphous Molybdenum Sulfide Films as Catalysts for Electrochemical Hydrogen Production in Water," Chemical Science, 2011.

Technology using catalysts which make hydrogen from formic acid could eventually replace lithium batteries and power a host of mobile devices.

Edman Tsang of Oxford University’s Department of Chemistry and colleagues are developing new catalysts which can produce hydrogen at room temperature without the need for solvents or additives.

Their initial results, reported in a recent paper in Nature Nanotechnology, are promising and suggest that a hydrogen fuel cell in your pocket might not be that far away.

The core-shell particle (palladium atoms on a silver nanoparticle).

The new approach involves placing a single atomic layer of palladium atoms onto silver nanoparticles. ‘The structural and electronic effects from the underlying silver greatly enhance the catalytic properties of palladium, giving impressive activity for the conversion of formic acid to hydrogen and carbon dioxide at room temperature,’ Edman told us.

He explains that the storage and handling of organic liquids, such as formic acid, is much easier and safer than storing hydrogen. The catalysts would enable the production of hydrogen from liquid fuel stored in a disposable or recycled cartridge, creating miniature fuel cells to power everything from mobile phones to laptops.

Another advantage of the new technology is that the gas stream generated from the reaction is mainly composed of hydrogen and carbon dioxide but virtually free from catalyst-poisoning carbon monoxide; removing the need for clean-up processes and extending the life of the fuel cells.

The chemists have worked closely with George Smith, Paul Bagot and co-workers at Oxford University’s Department of Materials to characterise the catalysts using atom probe tomography. The underlying technology is the subject of a recent Isis Innovation patent application.

‘There are lots of hurdles before you can get a real device, but we are looking at the possibility of using this new technology to replace lithium battery technology with an alternative which has a longer lifespan and has less impact on the environment,’ explains Edman.

Source: PhysOrg

To diversify the applications of superconductors that currently operate at chilly temperatures below 135 kelvin (K), scientists are searching for new classes of superconducting materials that will show this property at warmer temperatures. Now, a research team in Japan has synthesized a promising new class of superconductors1, made of Hg0.44ReO3, where an unusual motion of the mercury (Hg) atoms enhances superconducting properties at temperatures up to 7.7 K.

The crystal structure of HgxReO3. The mercury (Hg) atoms are shown in blue, oxygen (O) in red and rhenium (Re) in brown. Credit: 2011 The American Physical Society

The Dutch physicist Heike Kamerlingh Onnes discovered superconductivity one hundred years ago, when he noticed that the electrical resistance of mercury dropped to zero suddenly at 4.2 K. Superconducting materials are now used routinely in magnetic resonance imaging scanners.

In classical superconductors such as mercury, superconductivity arises through the combined vibrations of the atoms in the crystal. This makes the crystal structure a key factor for the superconducting properties of a material. In the case of HgxReO3, the atomic structure consists of rhenium (Re) and oxygen (O) building blocks. In the empty spaces between them, the mercury atoms arrange in chains (Fig. 1). However, some of the available places along these chains lack mercury atoms, and the team’s work suggests that this leads to an arrangement of paired mercury atoms.

"These pairs move within the channel in an oscillatory motion known as rattling", explains team-member Ayako Yamamoto from the RIKEN Advanced Science Institute in Wako. The rattling vibrations provide a strong feedback for the electrons, and therefore reinforce superconductivity in the material. In comparison to a similar structure lacking mercury pairs, the superconducting temperature of Hg0.44ReO3 at 7.7 K is almost twice as high. "Despite remaining below the present record of 135 K for a superconductor, there is potential for improving operation temperatures", says Yamamoto. “The application of pressure increases the superconducting temperature to 11.1 K, and this could mean that for the right crystal structure further enhancement is possible.”

Yamamoto and her colleagues are now working to optimize the crystal structure further—for example, by replacing rhenium with other elements. A better understanding of the influence of the mercury atoms’ rattling motion may also provide better insight into the mechanism of superconductivity in such structures. “Mercury seems to be a magic element in superconductivity, not only for its role in Kamerlingh Onnes’ discovery, but also for the fact that mercury is part of the material with the highest known superconducting temperature, HgBa2Ca2Cu3Ox,” Yamamoto explains. "Once more, mercury is playing a key role for new superconductors," she says.

Source: PhysOrg

When Gutenberg developed the principles of modern book printing, books became available to the masses. Hoping to bring technology capable of mass production to the nanometer scale, Udo Bach and this team of scientists at Monash University and the Lawrence Berkeley National Laboratory have developed a nanoprinting process modeled on Gutenberg’s printing method. Their goal is the simple, inexpensive production of nanotechnological components for solar cells, biosensors, and other electronic systems. As the researchers report in the journal Angewandte Chemie, their "ink" consists of gold nanoparticles, and the specific bonding between DNA molecules ensures its transfer to the substrate.

Nanopatterns with extremely high resolution are not difficult to produce with today’s technology. However, the methods used so far are analogous those used to produce the hand-written books of the era before Gutenberg; they are too slow and work-intensive for commercial fabrication. “New nanoprinting techniques offer an interesting solution,” says Bach. Along with co-workers, he has developed a process that works with a reusable “printing plate”.

The printing plate is a silicon wafer—like those used for the production of computer chips—that has been coated with a photoresist and covered with a mask. The wafer is then exposed to an electron beam (electron beam lithography). In the areas exposed to the beam, the photoresist is removed, exposing the wafer for etching. The wafer is then coated with gold. When the photoresist layer is removed, the gold only sticks to the etched areas. Polyethylene glycol chains are then bound specifically to the gold through sulfur–hydrogen groups. The chains have positively charged amino groups at their ends. The completed printing plate is then dipped into the “ink”, a solution of gold nanoparticles coated with negatively charged DNA molecules. Electrostatic attraction causes the DNA to stick to the amino groups, binding the gold nanoparticles to the gold-patterned areas of the printing plate.

The “paper” is a silicon wafer coated with a whisper-thin gold film and a layer of DNA. These DNA strands are complementary to those on the gold nanoparticles, with which they pair up to form double strands. This type of bond is stronger than the electrostatic attraction between the DNA and the amino groups. When the “paper” is pressed onto the “printing plate” and then removed, the gold nanoparticles from the ink remain stuck to the “paper” in the desired pattern. The “printing plate” can be cleaned and reused multiple times. Says Bach: “Our results demonstrate that it is possible to produce affordable printed elements based on nanoparticles.”

Source: PhysOrg

Proton exchange membrane fuel cells, also known as polymer electrolyte membrane fuel cells (PEMFCs), offer a way to power future emission-free vehicles, by providing stationary and portable power sources. However, the high cost and low durability of platinum catalysts are two major challenges hindering their commercialization. Researchers from the University of Western Ontario, and General Motors Research and Development Center have now discovered a new catalyst, platinum nanostars, that could make fuel cells more cost-effective and stable. [S. H. Sun et al., Angew Chem Int Ed (2011) 50, 422].

Pt is the most effective catalyst for fuel (usually hydrogen) oxidation at the anode and oxygen reduction reaction (ORR) at the cathode. The ORR is considerably slower than the oxidation of H2, and requires more catalyst. But Pt is expensive and relatively rare, and so has pushed up the price of fuel cells. At present, the most widely used cathode catalysts consist of fine particles of Pt supported on carbon black supports. In contrast to Pt nanoparticles, one-dimensional structures of Pt, such as nanowires, exhibit additional advantages associated with their anisotropy and unique structure.

Star-like single-crystal platinum nanostructures were produced, each with several nanowire arms with diameters of ~4 nm on carbon black. The carbon supported star-like Pt nanostructures (star-like PtNW/C) were synthesized in an environmentally friendly process, which does not require high temperatures, organic solvents, surfactants or complicated electrochemical deposition apparatus, by reducing a Pt precursor (H2PtCl6) with formic acid (HCOOH) in aqueous solution at room temperature.

The star-like PtNW/C showed greatly improved activity and durability compared to a state-of-the-art commercial catalyst made of Pt nanoparticles on carbon. More interestingly, the durability can be further improved by eliminating the carbon support.

The key reason this strategy works relies on the combination of a multi-armed network structure and the one-dimensional shape of the arms. This helps the activity and durability. In addition, the few surface defects and the preferential exposure of certain crystal facets further improves the activity. The increased activity and durability means that the amount of Pt needed on an electrode can be reduced, which could significantly lower the cost and increase the durability of PEMFCs.

Source: Materials Today

By directly linking the motions of two physically separated atoms, the technique has the potential to simplify information processing in future quantum computers and simulations.

Described in a paper published Feb. 23 by Nature, the NIST experiments enticed two beryllium ions (electrically charged atoms) to take turns vibrating in an electromagnetic trap, exchanging units of energy, or quanta, that are a hallmark of quantum mechanics. As little as one quantum was traded back and forth in these exchanges, signifying that the ions are "coupled" or linked together. These ions also behave like objects in the larger, everyday world in that they are "harmonic oscillators" similar to pendulums and tuning forks, making repetitive, back-and-forth motions.

"First one ion is jiggling a little and the other is not moving at all; then the jiggling motion switches to the other ion. The smallest amount of energy you could possibly see is moving between the ions," explains first author Kenton Brown, a NIST post-doctoral researcher. "We can also tune the coupling, which affects how fast they exchange energy and to what degree. We can turn the interaction on and off."

The experiments were made possible by a novel, one-layer ion trap cooled to minus 269 C (minus 452 F) with a liquid helium bath. The ions, 40 micrometers apart, float above the surface of the trap. In contrast to a conventional two-layer trap, the surface trap features smaller electrodes and can position ions closer together, enabling stronger coupling. Chilling to cryogenic temperatures suppresses unwanted heat that can distort ion behavior.

The energy swapping demonstrations begin by cooling both ions with a laser to slow their motion. Then one ion is cooled further to a motionless state with two opposing ultraviolet laser beams. Next the coupling interaction is turned on by tuning the voltages of the trap electrodes. In separate experiments reported in Nature, NIST researchers measured the ions swapping energy at levels of several quanta every 155 microseconds and at the single quantum level somewhat less frequently, every 218 microseconds. Theoretically, the ions could swap energy indefinitely until the process is disrupted by heating. NIST scientists observed two round-trip exchanges at the single quantum level.

To detect and measure the ions' activity, NIST scientists apply an oscillating pulse to the trap at different frequencies while illuminating both ions with an ultraviolet laser and analyzing the scattered light. Each ion has its own characteristic vibration frequency; when excited, the motion reduces the amount of laser light absorbed. Dimming of the scattered light tells scientists an ion is vibrating at a particular pulse frequency.

To turn on the coupling interaction, scientists use electrode voltages to tune the frequencies of the two ions, nudging them closer together. The coupling is strongest when the frequencies are closest. The motions become linked due to the electrostatic interactions of the positively charged ions, which tend to repel each other. Coupling associates each ion with both characteristic frequencies.

The new experiments are similar to the same NIST research group's 2009 demonstration of entanglement -- a quantum phenomenon linking properties of separated particles -- in a mechanical system of two separated pairs of vibrating ions. However, the new experiments coupled the oscillators' motions more directly than before and, therefore, may simplify information processing. In this case the researchers observed quantum behavior but did not verify entanglement.

The new technique could be useful in a future quantum computer, which would use quantum systems such as ions to solve problems that are intractable today. For example, quantum computers could break today's most widely used data encryption codes. Direct coupling of ions in separate locations could simplify logic operations and help correct processing errors. The technique is also a feature of proposals for quantum simulations, which may help explain the mechanisms of complex quantum systems such as high-temperature superconductors.

In addition, the demonstration also suggests that similar interactions could be used to connect different types of quantum systems, such as a trapped ion and a particle of light (photon), to transfer information in a future quantum network. For example, a trapped ion could act as a "quantum transformer" between a superconducting quantum bit (qubit) and a qubit made of photons.

Source: Science Daily

Working with funding from Google, they hope to make computers understand what it’s like to pursue an outcome only to be disappointed. That, they think, could really help computers predict the future.

While software may never know what it’s like to roll out of bed with splitting headache and dress quietly in the dark, it can certainly measure the distance between a desired outcome and the actual outcome achieved. And by doing so computers could learn to minimize “regret,” which in this case is measured by that distance.

TAU computer scientists working on learning theory and other thorny computer intelligence issues think that by teaching computers to reduce regret, they would essentially be teaching them to evaluate all the relevant variables surrounding an outcome in advance. This would allow them to do things like more efficiently route Internet traffic, prioritize server resource requests, or predict when traffic to a site might spike and provide the necessary capacity beforehand. And they could do it all based on data coming to them in real-time.

Source: Popsci