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Solar-Panel Windows Made Possible by Quantum Dot Breakthrough

Solar-Panel Windows Made Possible by Quantum Dot Breakthrough | Science and Medicine | Scoop.it
Researchers create transparent solar cells that could be used to replace windows and power homes in the future.

 

Luminescent solar concentrators are cost-effective complements to semiconductor photovoltaics that can boost the output of solar cells and allow for the integration of photovoltaic-active architectural elements into buildings (for example, photovoltaic windows).


Colloidal quantum dots are attractive for use in luminescent solar concentrators, but their small Stokes shift results in reabsorption losses that hinder the realization of large-area devices. Here, we use ‘Stokes-shift-engineered’ CdSe/CdS quantum dots with giant shells (giant quantum dots) to realize luminescent solar concentrators without reabsorption losses for device dimensions up to tens of centimeters.


Monte-Carlo simulations show a 100-fold increase in efficiency using giant quantum dots compared with core-only nanocrystals. We demonstrate the feasibility of this approach by using high-optical-quality quantum dot–polymethylmethacrylate nanocomposites fabricated using a modified industrial method that preserves the light-emitting properties of giant quantum dots upon incorporation into the polymer. Study of these luminescent solar concentrators yields optical efficiencies >10% and an effective concentration factor of 4.4. These results demonstrate the significant promise of Stokes-shift-engineered quantum dots for large-area luminescent solar concentrators.


Via Dr. Stefan Gruenwald
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Molecular scale MRI: System designed to peer into the atomic structure of individual molecules

Molecular scale MRI: System designed to peer into the atomic structure of individual molecules | Science and Medicine | Scoop.it

A team of scientists, led by Professor of Physics and of Applied Physics Amir Yacoby, has developed a magnetic resonance imaging (MRI) system that can produce nanoscale images, and may one day allow researchers to peer into the atomic structure of individual molecules. Their work is described in a March 23 paper in Nature Nanotechnology.


“What we’ve demonstrated in this new paper is the ability to get very high spatial resolution, and a fully operational MRI technology,” Yacoby said. “This work is directed toward obtaining detailed information on molecular structure. If we can image a single molecule and identify that there is a hydrogen atom here and a carbon there … we can obtain information about the structure of many molecules that cannot be imaged by any other technique today.”

 

Though not yet precise enough to capture atomic-scale images of a single molecule, the system already has been used to capture images of single electron spins. As the system is refined, Yacoby said he expects it eventually will be precise enough to peer into the structure of molecules.

While the system designed by Yacoby and colleagues operates in much the same way conventional MRIs do, the similarities end there.

 

“What we’ve done, essentially, is to take a conventional MRI and miniaturize it,” Yacoby said. “Functionally, it operates in the same way, but in doing that, we’ve had to change some of the components, and that has enabled us to achieve far greater resolution than conventional systems.”

 

Yacoby said that while conventional systems can achieve resolutions of less than a millimeter, they are effectively limited by the magnetic field gradient they can produce. Since those gradients fade dramatically within just feet, conventional systems built around massive magnets are designed to create a field large enough to image an object — like a human — that may be a meter or more in length.

 

The nanoscale system devised by Yacoby and colleagues, by comparison, uses a magnet that’s just 20 nanometers in diameter — about 300 times smaller than a red blood cell — but is able to generate a magnetic field gradient 100,000 times larger than even the most powerful conventional systems.


Via Dr. Stefan Gruenwald
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SpaceX's Reusable Falcon 9 Successfully Launches and Lands

SpaceX's Reusable Falcon 9 Successfully Launches and Lands | Science and Medicine | Scoop.it
American space company SpaceX successfully tested a stage of what they hope will eventually become a reusable rocket, the Falcon 9 Reusable (F9R).

 

Even as its Falcon 9 rocket blasted its Dragon cargo capsule towards the International Space Station last Friday, aerospace company SpaceX was preparing another feat. On Monday April 21, SpaceX launched a variant of the Falcon 9 design from its facility in Texas. The rocket in question is a prototype of the Falcon 9 Reusable (F9R).

 

The F9R successfully blasted off and rose to an altitude of 250 meters. The rocket briefly hovered at that altitude before safely descending back to the launch pad. The entire maneuver was captured on video by a drone aircraft.

 

SpaceX intends the F9R design eventually to become the first stage of the Falcon 9 rocket; such reusability would substantially reduce the cost of space launches, which currently rely upon disposal rockets. Future assessments will see the F9R launched from SpaceX’s New Mexico test facility. During those evaluations, the rocket will be launched with the landing legs tucked away and to greater heights to more closely approximate conditions during an actual launch and landing.

 

In the meantime, SpaceX Dragon capsules will continue to ferry cargo, and eventually astronauts, to the space station. Friday’s launch was the third of 12 planned Dragon cargo runs to the station as part of SpaceX’s $1.6 billion contract with NASA.

 
Via Dr. Stefan Gruenwald
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A Possible Cure for Ebola Virus Infection Discovered: BCX4430

A Possible Cure for Ebola Virus Infection Discovered: BCX4430 | Science and Medicine | Scoop.it

Ebola is one of the scariest viruses on Earth. Along with Marburg and a few other lesser known viruses, it is a member of the Filoviridae family, a nasty group of microbes that causes hemorrhagic fever. Like most viral diseases, patients with hemorrhagic fever will first present with flu-like symptoms. As the disease progresses, patients often bleed from their body orifices, such as their eyes and ears. Death, however, does not result from blood loss, but from shock or organ failure.

 

Hemorrhagic fevers are not easy to catch. Transmission generally requires prolonged contact with the patient or with his bodily fluids. Mortality rates depend on the particular viral strain. For Ebola, thedeadliest strain is Zaire, which can kill up to 90% of those infected. The worst ever outbreak occurred in Congo in 1976. That year, 318 people were infected and 280 died, a mortality rate of 88%. Currently, an outbreak of Ebola has killed at least 135 people in west Africa. The virus resembles Zaire, but researchers have determined that it is a brand new strain.

 

Obviously, finding a treatment or cure for such a frightening disease is desirable. With our highly interconnected world, it is only a matter of time before a hemorrhagic fever shows up on our doorstep. (Actually,that's already happened.) Unfortunately, at the present time, there is little that can be done for a victim of Ebola or any other hemorrhagic fever. Mostly, patients are kept hydrated and symptoms are treated as they arise. Other than that, doctors cross their fingers and hope the patient doesn't die.

 

That may be about to change. In the journal Nature, scientists -- who conducted much of their work in the secretive, high-containment biological laboratory maintained by USAMRIID at Fort Detrick, Maryland -- have reported the discovery of a small molecule that rescues rodents and monkeys from various hemorrhagic fevers. Even more, the drug exhibited activity against a wide range of viruses.

 

The molecule, named BCX4430, resembles the "A" found in DNA: adenosine. The RNA-based filoviruses also use "A" in their genomes. BCX4430, because it resembles "A", can be accidentally used by the virus when it is trying to grow inside of our cells. For the virus, this is a fatal mistake. BCX4430 blocks further growth and reproduction.


Shouldn't this drug be expected to hurt not only the virus, but humans as well? That would be a reasonable expectation, but for some reason, BCX4430 appears to only hurt the virus. Human cells appear not to be fooled by BCX4430 and do just fine in its presence. The most compelling experiment the research team ran involved the infection of cynomolgus macaque monkeys with deadly Marburg virus. Macaques were given twice daily doses of BCX4430 for 14 days beginning 1 hour, 24 hours, or 48 hours post-infection.


Amazingly, in vitro experiments showed that BCX4430 could potentially work against a wide range of viruses, including SARS, MERS, influenza, dengue, and measles.


Source: TK Warren et al. "Protection against filovirus diseases by a novel broad-spectrum nucleoside analogue BCX4430." Nature 508: 402-405 (2014). doi:10.1038/nature13027


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Today’s Antarctic region once as hot as California or Florida

Today’s Antarctic region once as hot as California or Florida | Science and Medicine | Scoop.it

Parts of ancient Antarctica were as warm as today’s California coast, and polar regions of the southern Pacific Ocean registered 21st-century Florida heat, according to scientists using a new way to measure past temperatures.

 

The findings, published the week of April 21, 2014 in the Proceedings of the National Academy of Sciences, underscore the potential for increased warmth at Earth’s poles and the associated risk of melting polar ice and rising sea levels, the researchers said.

 

Led by scientists at Yale, the study focused on Antarctica during the Eocene epoch, 40-50 million years ago, a period with high concentrations of atmospheric CO2 and consequently a greenhouse climate. Today, Antarctica is year-round one of the coldest places on Earth, and the continent’s interior is the coldest place, with annual average land temperatures far below zero degrees Fahrenheit.

 

But it wasn’t always that way, and the new measurements can help improve climate models used for predicting future climate, according to co-author Hagit Affek of Yale, associate professor of geology & geophysics.

 

“Quantifying past temperatures helps us understand the sensitivity of the climate system to greenhouse gases, and especially the amplification of global warming in polar regions,” Affek said.

The paper’s lead author, Peter M.J. Douglas, performed the research as a graduate student in Affek’s Yale laboratory. He is now a postdoctoral scholar at the California Institute of Technology. The research team included paleontologists, geochemists, and a climate physicist.

 

By measuring concentrations of rare isotopes in ancient fossil shells, the scientists found that temperatures in parts of Antarctica reached as high as 17 degrees Celsius (63F) during the Eocene, with an average of 14 degrees Celsius (57F)  — similar to the average annual temperature off the coast of California today.


Via Dr. Stefan Gruenwald
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Deanmignanelli's curator insight, July 15, 2014 10:34 PM

due to the current extreme climate changes the polar ice caps are melting due to carbon gases and this melting of the caps is causing major rising in the sea levels which is causeing disaster around the world due to water comming up past the sea barriers

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Land Rover debuts invisible car technology

Discovery Vision Concept's all new invisible car technology revealed. A first look at the intelligent next-generation innovation, a 'see-through' immersive a...
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