Quadriplegic Man Moves Again Just By Thinking

Bill Kochevar grabbed a mug of water, drew it to his lips and drank through the straw. His motions were slow and deliberate, but then Kochevar hadn’t moved his right arm or hand for eight years. And it took some practice to reach and grasp just by thinking about it. Kochevar, who was paralyzed below his shoulders in a bicycling accident, is believed to be the first person with quadriplegia in the world to have arm and hand movements restored with the help of two temporarily implanted technologies.

A brain-computer interface with recording electrodes under his skull, and a functional electrical stimulation (FES) system activating his arm and hand, reconnect his brain to paralyzed muscles. Holding a makeshift handle pierced through a dry sponge, Kochevar scratched the side of his nose with the sponge. He scooped forkfuls of mashed potatoes from a bowl—perhaps his top goal—and savored each mouthful. Kochevar (56, of Cleveland) is the focal point of research led by Case Western Reserve University, the Cleveland Functional Electrical Stimulation (FES) Center at the Louis Stokes Cleveland VA Medical Center and University Hospitals Cleveland Medical Center (UH).


brain implant2

For somebody who’s been injured eight years and couldn’t move, being able to move just that little bit is awesome to me,” said Kochevar. “It’s better than I thought it would be.”

 

He’s really breaking ground for the spinal cord injury community,” commented Bob Kirsch, chair of Case Western Reserve’s Department of Biomedical Engineering, executive director of the FES Center and principal investigator (PI) and senior author of the research. “This is a major step toward restoring some independence.”

A study of the work has been published in the The Lancet.

Source: http://thedaily.case.edu/

Solar Cells : How To Boost Efficiency Up To 30%

Researchers from the University of Houston have reported the first explanation for how a class of materials changes during production to more efficiently absorb light, a critical step toward the large-scale manufacture of better and less-expensive solar panels. The work, published this month as the cover story for Nanoscale, offers a mechanism study of how a perovskite thin film changes its microscopic structure upon gentle heating, said Yan Yao, assistant professor of electrical and computer engineering and lead author on the paper. This information is crucial for designing a manufacturing process that can consistently produce high-efficiency solar panels.

Perovskite cheap

Last year Yao and other researchers identified the crystal structure of the non-stoichiometric intermediate phase as the key element for high-efficiency perovskite solar cells. But what happened during the later thermal annealing step remained unclear. The work is fundamental science, Yao said, but critical for processing more efficient solar cells.

Otherwise, it’s like a black box,” he said. “We know certain processing conditions are important, but we don’t know why.”

The work also yielded a surprise: the materials showed a peak efficiency – the rate at which the material converted light to electricity – before the intermediate phase transformation was complete, suggesting a new way to produce the films to ensure maximum efficiency. Yao said researchers would have expected the highest efficiency to come after the material had been converted to 100 percent perovskite film. Instead, they discovered the best-performing solar devices were those for which conversion was stopped at 18 percent of the intermediate phase, before full conversion.

We found that the phase composition and morphology of solvent engineered perovskite films are strongly dependent on the processing conditions and can significantly influence photovoltaic performance,” the researchers wrote. “The strong dependence on processing conditions is attributed to the molecular exchange kinetics between organic halide molecules and DMSO (dimethyl sulfoxide) coordinated in the intermediate phase.

Perovskite compounds commonly are comprised of a hybrid organic-inorganic lead or tin halide-based material and have been pursued as potential materials for solar cells for several years. Yao said their advantages include the fact that the materials can work as very thin films – about 300 nanometers, compared with between 200 and 300 micrometers for silicon wafers, the most commonly used material for solar cells. Perovskite solar cells also can be produced by solution processing at temperatures below 150 degrees Centigrade (about 300 degrees Fahrenheit) making them relatively inexpensive to produce.

At their best, perovskite solar cells have an efficiency rate of about 22 percent, slightly lower than that of silicon (25 percent). But the cost of silicon solar cells is also dropping dramatically, and perovskite cells are unstable in air, quickly losing efficiency. They also usually contain lead, a toxin.

Still, Yao said, the materials hold great promise for the solar industry, even if they are unlikely to replace silicon entirely. Instead, he said, they could be used in conjunction with silicon, boosting efficiency to 30 percent or so.

Source: http://www.uh.edu/

Nanotechnology Boosts Oil Recovery

As oil producers struggle to adapt to , getting as much oil as possible out of every well has become even more important, despite concerns from nearby residents that some chemicals used to boost production may pollute underground water resources.

Researchers from the University of Houston have reported the discovery of a nanotechnology-based solution that could address both issues – achieving 15 percent tertiary oil recovery at low cost, without the large volume of chemicals used in most commercial fluids. The solution – graphene-based Janus amphiphilic nanosheets – is effective at a concentration of just 0.01 percent, meeting or exceeding the performance of both conventional and other nanotechnology-based fluids, said Zhifeng Ren, MD Anderson Chair professor of physics. Janus nanoparticles have at least two physical properties, allowing different chemical reactions on the same particle.

The low concentration and the high efficiency in boosting tertiary oil recovery make the nanofluid both more environmentally friendly and less expensive than options now on the market, said Ren, who also is a principal investigator at the Texas Center for Superconductivity at UH. He is lead author on a paper describing the work, published June 27 in the Proceedings of the National Academy of Sciences.

oil well

Our results provide a novel nanofluid flooding method for tertiary oil recovery that is comparable to the sophisticated chemical methods,” they wrote. “We anticipate that this work will bring simple nanofluid flooding at low concentration to the stage of oilfield practice, which could result in oil being recovered in a more environmentally friendly and cost-effective manner.

The U.S. Department of Energy estimates as much as 75 percent of recoverable reserves may be left after producers capture hydrocarbons that naturally rise to the surface or are pumped out mechanically, followed by a secondary recovery process using water or gas injection.

Traditional “tertiaryrecovery involves injecting a chemical mix into the well and can recover between 10 percent and 20 percent, according to the authors. But the large volume of chemicals used in tertiary oil recovery has raised concerns about potential environmental damage.

Obviously simple nanofluid flooding (containing only nanoparticles) at low concentration (0.01 wt% or less) shows the greatest potential from the environmental and economic perspective,” the researchers wrote.

Previously developed simple nanofluids recover less than 5 percent of the oil when used at a 0.01 percent concentration, they reported. That forces oil producers to choose between a higher nanoparticle concentration – adding to the cost – or mixing with polymers or surfactants. In contrast, they describe recovering 15.2 percent of the oil using their new and simple nanofluid at that concentration – comparable to chemical methods and about three times more efficient than other nanofluids.

Source: http://www.uh.edu/

How To Extract Molecules From Live Cells

University of Houston (UH) researchers have devised a new method for extracting molecules from live cells without disrupting cell development, work that could provide new avenues for the diagnosis of cancer and other diseases. The researchers used magnetized carbon nanotubes to extract biomolecules from live cells, allowing them to retrieve molecular information without killing the individual cells.

Most current methods of identifying intracellular information result in the death of the individual cells, making it impossible to continue to gain information and assess change over time, said Zhifeng Ren, M.D. Anderson Chair professor of physics and principal investigator at the Center for Superconductivity at UH and lead author of the paper. The work was a collaboration between Ren’s lab and that of Paul Chu, T.L.L. Temple Chair of Science and founding director of the Texas Center for Superconductivity.
Other key researchers on the project included Xiaoliu Zhang, a cancer researcher with the UH Center for Nuclear Receptors and Cell Signaling, and Dong Cai, assistant professor of physics. Chu, a co-author of the paper, said the new technique will allow researchers to draw fundamental information from a single cell.
cell
Now, (most) techniques break up many cells to extract the material inside the cells, so what you get is the average over many cells,” Zhifeng Ren said. “The individual cells may be different, but you cannot see exactly how they function.

A description of the work appears this week in the Proceedings of the National Academy of Sciences.
Source: http://www.uh.edu/