Heart of Canada's asbestos country reinvents itself

"We started with just two friends and two desks in an office, with no computer," recalled David Berthiaume, who runs Oleotek, a research center that develops industrial products from vegetable oils and animals fats, rather than oil byproducts.

The oleochemistry center, which now has a team of 11 a decade after its launch, has since migrated to spacious premises next to the former asbestos mine in Thetford Mines.

The city along with the nearby town of Asbestos benefited in the 1960s from the extraction of huge mineral deposits of the material banned by Europe in 2005.

A carcinogenic product, asbestos was long used in construction, where it was favored for its resistance to heat and fire.

But over the past 25 years the asbestos industry has collapsed, forcing Thetford Mines, a city of 25,700 inhabitants some 240 kilometers (150 miles) east of Montreal, to adapt its economic model to the changing times.

David Berthiaume, 36, owner and Cyril Devauchelle of Oleotek a green company based in the former headquarters of an asbestos mining company are shown in February 2012 in Thetford Mines, Quebec, Canada. Oleotek, is a research institute devoted to the development of industrial products from vegetable oil and animal fat, rather than petroleum.

His center has since launched a first start-up, Innoltek, which produces non-toxic concrete form release oil for the construction and precast concrete markets.

Once a mono-industrial city riddled with craters and slag heaps of snow-capped mining debris, Thetford Mines has since made huge strides in opening up its economy to new industries, from manufacturing and transportation to tourism, wind energy and research.

"In 20 years, 1,000 more jobs were created than were lost, but the salaries are not the same," said the city's Mayor Luc Berthold.

The average salary in Thetford Mines was among the highest in Canada during the 1970s, due to the extra compensation paid for working in risky mining jobs.

"People who worked in the mining sector had special training, whether in tinsmithing, mechanics, welding, etc. It was a good place to foster new businesses because there was specialized labor," said Luc Remillard, president of the local economic development agency.

There is no public data on the unemployment rate in the city, but the Chaudieres-Appalaches region that includes Thetford Mines has 5.7 percent unemployment, according to the Quebec Institute of Statistics. Remillard estimated Thetford Mines is on equal par with the regional figures.

For the first time in 130 years, Canada no longer produces asbestos. The Jeffrey Mine located in Asbestos -- until recently the world's biggest asbestos mine -- is now shuttered.

But it could soon receive a CAN$58 million (US$58.5 million) loan guarantee from the Quebec government to resume activities in the spring, despite protests from a local coalition asking authorities to halt further investments in the asbestos industry.

After a cave-in, LAB Chrysotile closed its Lake Asbestos Mine in October, near Thetford Mines. After going into bankruptcy, it is now seeking a new investor to start its operations back up again.

Despite the success of its economic diversification and the risks associated with asbestos, Thetford Mines officials are adamant about relaunching the Lake Asbestos Mine, which once employed 350 workers.

"Replacing 350 jobs with small businesses takes time. The easiest way for us to keep an active economy is to safeguard our mining operations," Berthold said.

"I don't have a miracle solution. We've been looking for five years for a big business to create 350-400 jobs here, but they don't come a dime a dozen."

(c) 2012 AFP

Could a computer one day rewire itself? New nanomaterial 'steers' electric currents in multiple dimensions

Scientists at Northwestern University have developed a new nanomaterial that can "steer" electrical currents. The development could lead to a computer that can simply reconfigure its internal wiring and become an entirely different device, based on changing needs.

As electronic devices are built smaller and smaller, the materials from which the circuits are constructed begin to lose their properties and begin to be controlled by quantum mechanical phenomena. Reaching this physical barrier, many scientists have begun building circuits into multiple dimensions, such as stacking components on top of one another.

The Northwestern team has taken a fundamentally different approach. They have made reconfigurable electronic materials: materials that can rearrange themselves to meet different computational needs at different times.

"Our new steering technology allows use to direct current flow through a piece of continuous material," said Bartosz A. Grzybowski, who led the research. "Like redirecting a river, streams of electrons can be steered in multiple directions through a block of the material -- even multiple streams flowing in opposing directions at the same time."

Grzybowski is professor of chemical and biological engineering in the McCormick School of Engineering and Applied Science and professor of chemistry in the Weinberg College of Arts and Sciences.

The Northwestern material combines different aspects of silicon- and polymer-based electronics to create a new classification of electronic materials: nanoparticle-based electronics.

The study, in which the authors report making preliminary electronic components with the hybrid material, will be published online Oct. 16 by the journal Nature Nanotechnology. The research also will be published as the cover story in the November print issue of the journal.

"Besides acting as three-dimensional bridges between existing technologies, the reversible nature of this new material could allow a computer to redirect and adapt its own circuitry to what is required at a specific moment in time," said David A. Walker, an author of the study and a graduate student in Grzybowski's research group.

Imagine a single device that reconfigures itself into a resistor, a rectifier, a diode and a transistor based on signals from a computer. The multi-dimensional circuitry could be reconfigured into new electronic circuits using a varied input sequence of electrical pulses.

The hybrid material is composed of electrically conductive particles, each five nanometers in width, coated with a special positively charged chemical. (A nanometer is a billionth of a meter.) The particles are surrounded by a sea of negatively charged atoms that balance out the positive charges fixed on the particles. By applying an electrical charge across the material, the small negative atoms can be moved and reconfigured, but the relatively larger positive particles are not able to move.

By moving this sea of negative atoms around the material, regions of low and high conductance can be modulated; the result is the creation of a directed path that allows electrons to flow through the material. Old paths can be erased and new paths created by pushing and pulling the sea of negative atoms. More complex electrical components, such as diodes and transistors, can be made when multiple types of nanoparticles are used.

The title of the paper is "Dynamic Internal Gradients Control and Direct Electric Currents Within Nanostructured Materials." In addition to Grzybowski and Walker, other authors are Hideyuki Nakanishi, Paul J. Wesson, Yong Yan, Siowling Soh and Sumanth Swaminathan, from Northwestern, and Kyle J. M. Bishop, a former member of the Grzybowski research group, now with Pennsylvania State University.

Story Source:

The above story is reprinted (with editorial adaptations) from materials provided by Northwestern University, via EurekAlert!, a service of AAAS.

Journal Reference:

Hideyuki Nakanishi, David A. Walker, Kyle J. M. Bishop, Paul J. Wesson, Yong Yan, Siowling Soh, Sumanth Swaminathan, Bartosz A. Grzybowski. Dynamic internal gradients control and direct electric currents within nanostructured materials. Nature Nanotechnology, 2011; DOI: 10.1038/nnano.2011.165

Molecules 'light up' Alzheimer's roots: Light-switching complex attaches itself to amyloid proteins

 A breakthrough in sensing at Rice University could make finding signs of Alzheimer's disease nearly as simple as switching on a light.

The technique reported in the Journal of the American Chemical Society should help researchers design better medications to treat the devastating disease.

The lab of Rice bioengineer Angel Martí is testing metallic molecules that naturally attach themselves to a collection of beta amyloid proteins called fibrils, which form plaques in the brains of Alzheimer's sufferers. When the molecules, complexes of dipyridophenazine ruthenium, latch onto amyloid fibrils, their photoluminescence increases 50-fold.

The large increase in fluorescence may be an alternative to molecules currently used to study amyloid fibrils, which researchers believe form when misfolded proteins begin to aggregate. Researchers use changes in fluorescence to characterize the protein transition from disordered monomers to aggregated structures.

Nathan Cook, a former Houston high school teacher and now a Rice graduate student and lead author of the new paper, began studying beta amyloids when he joined Martí's lab after taking a Nanotechnology for Teachers course taught by Rice Dean of Undergraduates and Professor of Chemistry John Hutchinson. Cook's goal was to find a way to dissolve amyloid fibrils in Alzheimer's patients.

But the Colorado native's research led him down a different path when he realized the ruthenium complexes, the subject of much study in Martí's group, had a distinctive ability to luminesce when combined in a solution with amyloid fibrils.

Such fibrils are simple to make in the lab, he said. Molecules of beta amyloid naturally aggregate in a solution, as they appear to do in the brain. Ruthenium-based molecules added to the amyloid monomers do not fluoresce, Cook said. But once the amyloids begin to aggregate into fibrils that resemble "microscopic strands of spaghetti," hydrophobic parts of the metal complex are naturally drawn to them. "The microenvironment around the aggregated peptide changes and flips the switch" that allows the metallic complexes to light up when excited by a spectroscope, he said.

Thioflavin T (ThT) dyes are the standard sensors for detecting amyloid fibrils and work much the same way, Marti said. But ThT has a disadvantage because it fluoresces when excited at 440 nanometers and emits light at 480 nanometers -- a 40-nanometer window.

That gap between excitation and emission wavelengths is known as the Stokes shift. "In the case of our metal complexes, the Stokes is 180 nanometers," said Martí, an assistant professor of chemistry and bioengineering. "We excite at 440 and detect in almost the near-infrared range, at 620 nanometers.

"That's an advantage when we want to screen drugs to retard the growth of amyloid fibrils," he said. "Some of these drugs are also fluorescent and can obscure the fluorescence of ThT, making assays unreliable."

Cook also exploited the metallic's long-lived fluorescence by "time gating" spectroscopic assays. "We specifically took the values only from 300 to 700 nanoseconds after excitation," he said. "At that point, all of the fluorescent media have pretty much disappeared, except for ours. The exciting part of this experiment is that traditional probes primarily measure fluorescence in two dimensions: intensity and wavelength. We have demonstrated that we can add a third dimension -- time -- to enhance the resolution of a fluorescent assay."

The researchers said their complexes could be fitting partners in a new technique called fluorescence lifetime imaging microscopy, which discriminates microenvironments based on the length of a particle's fluorescence rather than its wavelength.

Cook's goal remains the same: to treat Alzheimer's -- and possibly such other diseases as Parkinson's -- through the technique. He sees a path forward that may combine the ruthenium complex's ability to target fibrils and other molecules' potential to dissolve them in the brain.

"That's something we are actively trying to target," Martí said.

More information: http://pubs.acs.or … 21/ja204656r

Provided by Rice University (news : web)

A scratched coating heals itself quickly and easily, with light not heat (w/ video)

 Imagine you're driving your own new car--or a rental car--and you need to park in a commercial garage. Maybe you're going to work, visiting a mall or attending an event at a sports stadium, and you're in a rush. Limited and small available spots and concrete pillars make parking a challenge. And it happens that day: you slightly misjudge a corner and you can hear the squeal as you scratch the side of your car--small scratches, but large anticipated repair costs.

Now imagine that that you can repair these unsightly scratches yourself--quickly, easily and inexpensively. . . . or that you can go through a car wash that can detect these and other more minor scratches and fix them as the car goes through the washing garage. Fantasy? Not exactly. Not anymore. Not according to a new discovery detailed in the April 21 issue of the journal Nature, and depicted in a short video interview and simulation:

This video is not supported by your browser at this time.

A team of researchers in the United States and Switzerland have developed a polymer-based material that can heal itself with the help of a widely used type of lighting. Called "metallo-supramolecular polymers," the material is capable of becoming a supple liquid that fills crevasses and gaps left by scrapes and scuffs when placed under ultraviolet light for less than a minute and then resolidifying.

"This is ingenious and transformative materials research," said Andrew Lovinger, polymers program director in NSF's Division of Materials Research. "It demonstrates the versatility and power of novel polymeric materials to address technological issues and serve society while creating broadly applicable scientific concepts."

The team involves researchers at Case Western Reserve University in Cleveland, Ohio, led by Stuart J. Rowan; the Adolphe Merkle Institute of the University of Fribourg in Switzerland, led by Christoph Weder; and the Army Research Laboratory at Aberdeen Proving Ground in Maryland, led by Rick Beyer.

The scientists envision widespread uses in the not-so-distant future for re-healable materials like theirs, primarily as coatings for consumer goods such as automobiles, floors and furniture. While their polymers are not yet ready for commercial use, they acknowledge, they now have proved that the concept works. And with that, what happens next is up to the market place. Necessity, the mother of invention, will expand the possibilities for commercial applications.

"These polymers have a Napoleon Complex," explains lead author Stuart Rowan, a professor of macromolecular engineering and science and director of the Institute for Advanced Materials at Case Western Reserve University. "In reality they're pretty small but are designed to behave like they're big by taking advantage of specific weak molecular interactions."

"Our study is really a fundamental research study," said Christoph Weder, a professor of polymer chemistry and materials and the director of the Adolphe Merkle Institute. "We tried to create materials that have a unique property matrix, that have unique functionality and that in principle could be very useful."

Specifically, the new materials were created by a mechanism known as supramolecular assembly. Unlike conventional polymers, which consist of long, chain-like molecules with thousands of atoms, these materials are composed of smaller molecules, which were assembled into longer, polymer-like chains using metal ions as "molecular glue" to create the metallo-supramolecular polymers.

While these metallo-supramolecular polymers behave in many ways like normal polymers, when irradiated with intense ultraviolet light the assembled structures become temporarily unglued. This transforms the originally solid material into a liquid that flows easily. When the light is switched off, the material re-assembles and solidifies again; its original properties are restored.

Using lamps such as those dentists use to cure fillings, the researchers repaired scratches in their polymers. Wherever they waved the light beam, the scratches filled up and disappeared, much like a cut that heals and leaves no trace on skin. While skin's healing process can be represented by time-lapse photography that spans several days or weeks, self-healing polymers heal in just seconds.

In addition, unlike the human body, durability of the material does not seem to be compromised by repeated injuries. Tests showed the researchers could repeatedly scratch and heal their materials in the same location.

Further, while heat has provided a means to heal materials for a long time, the use of light provides distinct advantages, says Mark Burnworth, a graduate student at Case Western Reserve University. "By using light, we have more control as it allows us to target only the defect and leave the rest of the material untouched."

The researchers systematically investigated several new polymers to find an optimal combination of mechanical properties and healing ability. They found that metal ions that drive the assembly process via weaker chemical interactions serve best as the light-switchable molecular glue.

They also found the materials that assembled in the most orderly microstructures had the best mechanical properties. But, healing efficiency improved as structural order decreased.

"Understanding these relationships is critical for allowing us improve the lifetime of coatings tailored to specific applications, like windows in abrasive environments" Beyer said.

And what's next? According to Rowan, "One of our next steps is to use the concepts we have shown here to design a coating that would be more applicable in an industrial setting."

Film director and art curator Aaron Rose was at least partially right when he said, "In the right light, at the right time, everything is extraordinary." Self-healing polymers certainly are extraordinary.

Provided by National Science Foundation (news : web)