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Scooped by Dr. Stefan Gruenwald!

Casting Custom-Shaped Inorganic Structures with DNA Molds

Casting Custom-Shaped Inorganic Structures with DNA Molds | Amazing Science |
Researchers at the Wyss Institute for Biologically Inspired Engineering at Harvard University have unveiled a new method to form tiny 3D metal nanoparticles in prescribed shapes and dimensions using DNA, Nature's building block, as a construction mold.

The ability to mold inorganic nanoparticles out of materials such as gold and silver in precisely designed 3D shapes is a significant breakthrough that has the potential to advance laser technology, microscopy, solar cells, electronics, environmental testing, disease detection and more.

"We built tiny foundries made of stiff DNA to fabricate metal nanoparticles in exact three–dimensional shapes that we digitally planned and designed," said Peng Yin, senior author of the paper, Wyss Core Faculty member and Assistant Professor of Systems Biology at Harvard Medical School.

The Wyss team's findings, described in a paper titled "Casting Inorganic Structures with DNA Molds," were published today in Science. The work was done in collaboration with MIT's Laboratory for Computational Biology and Biophysics, led by Mark Bathe, senior co–author of the paper.

"The paper's findings describe a significant advance in DNA nanotechnology as well as in inorganic nanoparticle synthesis," Yin said. For the very first time, a general strategy to manufacture inorganic nanoparticles with user-specified 3D shapes has been achieved to produce particles as small as 25 nanometers or less, with remarkable precision (less than 5 nanometers). A sheet of paper is approximately 100,000 nanometers thick.

The 3D inorganic nanoparticles are first conceived and meticulously planned using computer design software. Using the software, the researchers design three–dimensional "frameworks" of the desired size and shape built from linear DNA sequences, which attract and bind to one another in a predictable manner.

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Astrocytes can repair the brain after stroke

Astrocytes can repair the brain after stroke | Amazing Science |
A previously unknown mechanism, through which astrocytes in the brain produce new nerve cells after a stroke, has been discovered by researchers at Karolinska Institutet and Lund University. The findings are published in the journal Science.

Neurogenesis is restricted in the adult mammalian brain; most neurons are neither exchanged during normal life nor replaced in pathological situations. Scientists now report that stroke elicits a latent neurogenic program in striatal astrocytes in mice. Notch1 signaling is reduced in astrocytes after stroke, and attenuated Notch1 signaling is necessary for neurogenesis by striatal astrocytes. Blocking Notch signaling triggers astrocytes in the striatum and the medial cortex to enter a neurogenic program, even in the absence of stroke, resulting in 850 ± 210 (mean ± SEM) new neurons in a mouse striatum. Thus, under Notch signaling regulation, astrocytes in the adult mouse brain parenchyma carry a latent neurogenic program that may potentially be useful for neuronal replacement strategies.

Principal Investigator of this study has been Jonas Frisén, professor at the Department of Cell and Molecular Biology, Karolinska Institutet. First study-author is Jens Magnusson, a doctoral student in Jonas Frisén’s lab. The team also identified the signaling mechanism that regulates the conversion of the astrocytes to nerve cells. In a healthy brain, this signalling mechanism is active and inhibits the conversion and, consequently, the astrocytes do not generate nerve cells. Following a stroke, the signaling mechanism is suppressed and astrocytes can start the process of generating new cells.


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First ultraluminous pulsar found: NuSTAR discovers impossibly bright dead star with energy release of 10 million suns

First ultraluminous pulsar found: NuSTAR discovers impossibly bright dead star with energy release of 10 million suns | Amazing Science |

Astronomers working with NASA's Nuclear Spectroscopic Telescope Array (NuSTAR), led by Caltech's Fiona Harrison, have found a pulsating dead star beaming with the energy of about 10 million suns. The object, previously thought to be a black hole because it is so powerful, is in fact a pulsar—the incredibly dense rotating remains of a star.

"This compact little stellar remnant is a real powerhouse. We've never seen anything quite like it," says Harrison, NuSTAR's principal investigator and the Benjamin M. Rosen Professor of Physics at Caltech. "We all thought an object with that much energy had to be a black hole."

Dom Walton, a postdoctoral scholar at Caltech who works with NuSTAR data, says that with its extreme energy, this pulsar takes the top prize in the weirdness category. Pulsars are typically between one and two times the mass of the sun. This new pulsar presumably falls in that same range but shines about 100 times brighter than theory suggests something of its mass should be able to.

"We've never seen a pulsar even close to being this bright," Walton says. "Honestly, we don't know how this happens, and theorists will be chewing on it for a long time." Besides being weird, the finding will help scientists better understand a class of very bright X-ray sources, called ultraluminous X-ray sources (ULXs).

Harrison, Walton, and their colleagues describe NuSTAR's detection of this first ultraluminous pulsar in a paper that appears in the current issue of Nature.

"This was certainly an unexpected discovery," says Harrison. "In fact, we were looking for something else entirely when we found this."

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Hybrid materials could smash the solar efficiency ceiling by extracting electrons from dark triplet excitons

Hybrid materials could smash the solar efficiency ceiling by extracting electrons from dark triplet excitons | Amazing Science |
Researchers have developed a new method for harvesting the energy carried by particles known as ‘dark’ spin-triplet excitons with close to 100% efficiency, clearing the way for hybrid solar cells which could far surpass current efficiency limits.

The team, from the University of Cambridge, have successfully harvested the energy of triplet excitons, an excited electron state whose energy in harvested in solar cells, and transferred it from organic to inorganic semiconductors. To date, this type of energy transfer had only been shown for spin-singlet excitons. The results are published in the journal Nature Materials.

In the natural world, excitons are a key part of photosynthesis: light photons are absorbed by pigments and generate excitons, which then carry the associated energy throughout the plant. The same process is at work in a solar cell.

In conventional semiconductors such as silicon, when one photon is absorbed it leads to the formation of one free electron that can be extracted as current. However, in pentacene, a type of organic semiconductor, the absorption of a photon leads to the formation of two electrons. But these electrons are not free and they are difficult to pin down, as they are bound up within ‘dark’ triplet exciton states.

Excitons come in two ‘flavours’: spin-singlet and spin-triplet. Spin-singlet excitons are ‘bright’ and their energy is relatively straightforward to harvest in solar cells. Triplet-spin excitons, in contrast, are ‘dark’, and the way in which the electrons spin makes it difficult to harvest the energy they carry.

“The key to making a better solar cell is to be able to extract the electrons from these dark triplet excitons,” said Maxim Tabachnyk, a Gates Cambridge Scholar at the University’s Cavendish Laboratory, and the paper’s lead author. “If we can combine materials like pentacene with conventional semiconductors like silicon, it would allow us to break through the fundamental ceiling on the efficiency of solar cells.”

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Harvard scientist creates functional insulin-producing human beta cells

Harvard scientist creates functional insulin-producing human beta cells | Amazing Science |

The generation of insulin-producing pancreatic β cells from stem cells in vitro would provide an unprecedented cell source for drug discovery and cell transplantation therapy in diabetes. However, insulin-producing cells previously generated from human pluripotent stem cells (hPSC) lack many functional characteristics of bona fide β cells. Here, we report a scalable differentiation protocol that can generate hundreds of millions of glucose-responsive β cells from hPSC in vitro. These stem-cell-derived β cells (SC-β) express markers found in mature β cells, flux Ca2+ in response to glucose, package insulin into secretory granules, and secrete quantities of insulin comparable to adult β cells in response to multiple sequential glucose challenges in vitro. Furthermore, these cells secrete human insulin into the serum of mice shortly after transplantation in a glucose-regulated manner, and transplantation of these cells ameliorates hyperglycemia in diabetic mice.

Xander University Professor Douglas Melton and colleagues have figured out the complex series of steps necessary to turn stem cells into beta cells. Beta cells are the sugar-sensing, insulin-secreting cells of the pancreas that are missing in Type 1 diabetics, casualties of the body’s own immune attack on itself.

“We wanted to replace insulin injections” with “nature’s own solution,” says Melton, who has been a leading scientist in and advocate for the field of stem-cell biologyever since he switched from studying developmental biology in frogs after his young son, and later his daughter, were diagnosed with Type 1 diabetes.

He is now co-director of the Harvard Stem Cell Institute (HSCI) and co-chair of the Harvard department of stem cell and regenerative biology (in the Faculties of Medicine and of Arts and Sciences).

What Melton reports in the journal Cell on October 9 is that his lab, including co-first authors Felicia W. Pagliuca, Jeff Millman, and Mads Gurtler (as well as a Harvard undergraduate and others), have succeeded in developing a procedure for making hundreds of millions of pancreatic beta cells in vitro. These cells, Melton explains, “read the amount of sugar in the blood, and then secrete just the right amount insulin in a way that is so exquisitely accurate that I don’t believe it will ever be reproduced by people injecting insulin or by a pump injecting that insulin.”

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An Europa-Io Moon Sample Return Mission

An Europa-Io Moon Sample Return Mission | Amazing Science |

A short while ago the Obama Administration released its proposed budget for FY2015.  NASA’s budget (which is almost certainly subject to change by Congress as has been the case for decades) would stay essentially flat at $17.5 billion and Planetary Science would get nearly $1.3 billion or just $65 million less than what Congress approved for the current fiscal year.  Included in the budget is $15 million for continued studies of a mission to Jupiter’s moon, Europa, in the 2020s.  But instead of a full blown flagship-class mission, the Administration is proposing that the Europa mission have a cost target of under a billion dollars.  This is just a fraction of the cost of missions like the proposed $2.1 billion Europa Clipper currently under study which itself is a fraction of the cost of the earlier proposed $4.7 billion Europa Orbiter.  As the planetary science community scrambles to figure out how to meet such a tight budget cap to such a difficult-to-reach (but scientifically fascinating) target like Europa, I would like to make a suggestion: A sample return mission to Europa.

A little over a year ago, the popular space press was filled with a flurry of stories about a proposed, low-cost sample return mission to Saturn’s moon, Enceladus.  Proposed by a team led by Peter Tsou of Sample Exploration Systems in La Canada, California, the LIFE (Life Investigation For Enceladus) mission would have a spacecraft fly through the geyser plumes in Enceladus’ southern polar region and use an aerogel collector (of the same sort successfully employed by NASA in the Stardust mission to return samples of cometary dust in 2006) to secure samples of the plumes’ icy particles for return to the Earth where they could be studied in detail.  Earlier concepts of the LIFE mission also included sample collection of Saturn’s E-ring (believed to be generated by particles that escaped Enceladus’ geysers into orbit around Saturn) and even the atmosphere of Titan.  The proposed mission offers an affordable means of securing samples from the watery (potentially life-supporting) environment beneath this moon’s icy crust using readily available technology.

In a presentation made last June at the LCPM-10 conference at Caltech, Tsou and his team outlined their vision for their proposed Discovery-class LIFE mission [1]:  The 15-year LIFE mission would be launched in the early 2020s and employ a spacecraft with a ~800 kg dry mass possessing a ~3000 m/s Δv capability.  Assuming a storable, bipropellant propulsion system with a specific impulse of ~300 seconds like those typically used by other NASA planetary spacecraft, the launch mass would be something on the order of ~2,200 kg.  There are a number of possible mission profiles depending on the launch date and other factors, but in one proposed mission scenario, LIFE would be launched in November 2021 and use a VEEGA (Venus-Earth-Earth Gravity Assist) trajectory to gain the speed needed to reach Saturn using a smaller (and more affordable) launch vehicle.  The Venus flyby would take place in April 2022, the first Earth flyby would occur in March 2023 and the final Earth flyby in June 2026.  The spacecraft would then hibernate (to save on mission operation costs) until just before reaching Saturn in May 2030.

After entering orbit around Saturn, LIFE would use five close passes by Saturn’s largest moon, Titan, over the course of 128 days to gradually alter the probe’s orbit so that it could make multiple low-speed (3.7 to 4 km/s) passes through the geysers in the southern polar regions of Enceladus where an aerogel collector would secure samples of the plumes’ ice particles.  This is lower than Stardust’s 6.1 km/s encounter velocity with Comet Wild 2 in January 2006 and would result in better preservation of fragile ice particles.

After the encounters with Enceladus are completed, seven additional Titan flybys over 152 days would gradually pump up LIFE’s orbit in preparation for its departure.  After spending about two years in orbit around Saturn, LIFE would use its propulsion system to escape Saturn and begin the ~4.5 year long voyage back to Earth.  Sometime in late 2036, the return capsule would detach from the main spacecraft and reenter Earth’s atmosphere at a speed of 16 to 18 km/s.  The total Discovery-class mission cost would be about $425 million, excluding launch, and is advertised to generate flagship-class quality science on a Discovery-class budget.


[1] P. Tsou, D.E. Brownlee, C.P. McKay, A. Anbar, H. Yano, Nathan Strange, Richard Dissly and I Kanik, “Low Cost Enceladus Sample Return Mission Concept”, Low Cost Planetary Mission Conference – 10 (Pasadena, CA; June 18 – 20, 2013), 2013 (presentation)

[2] Lorenz Roth, Joachim Saur, Kurt D. Retherford, Darrell F. Strobel, Paul D. Feldman, Melissa A. McGrath and Francis Nimmo, “Transient Water Vapor at Europa’s South Pole”, Science, Vol. 343, No. 6167, pp. 171-174, January 10, 2014 (abstract)

[3] “Hubble Space Telescope Sees Evidence of Water Vapor Venting off Jovian Moon”, News Release No. STScI-2013-55, December 12, 2013 (press release)

[4] Mission Design Center Trajectory Browser, NASA Ames Research Center (web site)

[5] “Galileo”, in Janes Space Directory 2001-2002, David Baker (editor), pp. 457-461, Janes Information Group Ltd., 2001

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Milky Way's amount of Dark Matter is 800,000,000,000 times the mass of our Sun

Milky Way's amount of Dark Matter is 800,000,000,000 times the mass of our Sun | Amazing Science |
A new measurement of dark matter in the Milky Way has revealed there is half as much of the mysterious substance as previously thought.

Australian astronomers used a method developed almost 100 years ago to discover that the weight of dark matter in our own galaxy is 800,000,000,000 (or 8 x 1011) times the mass of the Sun. They probed the edge of the Milky Way, looking closely, for the first time, at the fringes of the galaxy about 5 million billion kilometres from Earth.

Astrophysicist Dr Prajwal Kafle, from The University of Western Australia node of the International Centre for Radio Astronomy Research, said we have known for a while that most of the Universe is hidden.

"Stars, dust, you and me, all the things that we see, only make up about 4 per cent of the entire Universe," he said.

"About 25 per cent is dark matter and the rest is dark energy." Dr Kafle, who is originally from Nepal, was able to measure the mass of the dark matter in the Milky Way by studying the speed of stars throughout the galaxy, including the edges, which had never been studied to this detail before.

He used a robust technique developed by British astronomer James Jeans in 1915 -- decades before the discovery of dark matter. Dr Kafle's measurement helps to solve a mystery that has been haunting theorists for almost two decades.

"The current idea of galaxy formation and evolution, called the Lambda Cold Dark Matter theory, predicts that there should be a handful of big satellite galaxies around the Milky Way that are visible with the naked eye, but we don't see that," Dr Kafle said.

"When you use our measurement of the mass of the dark matter the theory predicts that there should only be three satellite galaxies out there, which is exactly what we see; the Large Magellanic Cloud, the Small Magellanic Cloud and the Sagittarius Dwarf Galaxy."

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World's Longest Neutrino Beam Will Explore Why the Universe Still Exists

World's Longest Neutrino Beam Will Explore Why the Universe Still Exists | Amazing Science |

Scientists believe that a better understanding of neutrinos, one of the most abundant and difficult-to-study particles, may lead to a clearer picture of the origins of matter and the inner workings of the universe. Using the world’s most powerful beam of neutrinos , generated at the U.S. Department of Energy’s Fermi National Accelerator Laboratory near Chicago, the NOvA experimentcan precisely record the telltale traces of those rare instances when one of these ghostly particles interacts with matter.

For the next six years, Fermilab will send tens-of thousands of billions of neutrinos every second in a beam aimed at both detectors, and scientists expect to catch only a few each day in the far detector, so rarely do neutrinos interact with matter.

From this data, scientists hope to learn more about how and why neutrinos change between one type and another. The three types, called flavors, are the muon, electron and tau neutrino. Over longer distances, neutrinos can flip between these flavors. NOvA is specifically designed to study muon neutrinos changing into electron neutrinos. Unraveling this mystery may help scientists understand why the universe is composed of matter, and why that matter was not annihilated by antimatter after the Big Bang.

NOvA, is the most powerful accelerator-based neutrino experiment ever built in the United States, and the longest-distance one in the world. It’s called and after nearly five years of construction, scientists are now using the two massive detectors – placed 500 miles apart – to study one of nature’s most elusive subatomic particles. Scientists will also probe the still-unknown masses of the three types of neutrinos in an attempt to determine which is the heaviest. Construction on NOvA’s two massive neutrino detectors began in 2009.

“With every neutrino interaction recorded, we learn more about these particles and their role in shaping our universe,” said James Siegrist, DOE Associate Director of Science for High Energy Physics.

NOvA’s particle detectors were both constructed in the path of the neutrino beam sent from Fermilab in Batavia, Illinois , to northern Minnesota. The 300-ton near detector, installed underground at the laboratory, observes the neutrinos as they embark on their near-light-speed journey through the earth, with no tunnel needed. The 14,000-ton far detector - constructed in Ash River, Minnesota, near the Canadian border – spots those neutrinos after their 500-mile trip, and allows scientists to analyze how they change over that long distance.

The far detector in Minnesota is believed to be the largest free-standing plastic structure in the world, at 200 feet long, 50 feet high and 50 feet wide. Both detectors are constructed from PVC, and filled with a scintillating liquid that gives off light when a neutrino interacts with it. Fiber optic cables transmit that light to a data acquisition system, which creates 3-D pictures of those interactions for scientists to analyze.
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Quantum camera can take photos in almost complete darkness, needs less than one photon per pixel

Quantum camera can take photos in almost complete darkness, needs less than one photon per pixel | Amazing Science |
Using quantum-entangled pairs of photons as the shutter trigger for a super-high-speed camera, researchers can actually create images from less than a single photon per pixel.

It’s no secret that cameras are quickly getting better at capturing images in low light. Researchers at the University of Glasgow have pushed this trend to create an imager that can work with less than 1 photon per pixel. By combining two esoteric technologies — photon heralding and compressive imaging– the team has achieved a milestone that on the surface seems impossible. Leaving aside the huge amount of math and physics required under the covers, the process itself is actually fairly straightforward and very clever.

The first half of the weird science — which is also called “ghost imaging” — is based on what are called heralded photons. Under certain circumstances pairs of quantum-entangled photons can be produced using a process called spontaneous parametric down-conversion (SPDC) and then split apart. Most of the time, when you detect one, the other one can also be detected. The detection of the first photon “heralds” the existence of the second.

The team’s imager uses a beam splitter to send one of each pair of photons it creates through the object being imaged (the camera only works for creating images of transmissive targets) and to a very sensitive single-pixel detector. It sends the other to a high-speed camera. The detector is only activated when a photon is sensed coming through the target object. When one does, the detector sends a signal to open the shutter of the camera — located at the end of the path of the other photon from the original pair — for about 15 nanoseconds. That’s long enough to record the position of the second — heralded — photon, but short enough to keep out almost all background noise. In essence, the single-pixel detector acts as a very high-speed shutter for the camera, so that it only takes pictures of photons that have passed through the target. To allow time for the shutter release signal to get from the detector to the camera, a delay line of about 70 nanoseconds is added to the photon’s path to the camera.

This use of heralded photons gets the imager’s light needs down to almost one photon per pixel — although there is still the unavoidable shot noise that comes with the Poisson distribution of photons. Compressive imaging allow the imager to deal with this noise, and to to push the boundaries even further – to less than one photon per pixel. By relying on the inherent redundancy of information in natural subjects, compressive imaging uses frequency domain information – in this case generated by performing a Discrete Cosine Transform (DCT) on the image — to essentially reconstruct portions of the image that were not directly captured.

This amazing camera isn’t just for show. The team hopes it can lead to the development of cameras for use in science research that can be used to study and document subjects that are very light-sensitive, like certain biological specimens.

Reference: arXiv:1408.6381 - "Imaging with a small number of photons"

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Mapping Wi-Fi dead zones with Helmholtz equation

Mapping Wi-Fi dead zones with Helmholtz equation | Amazing Science |

A home's Wi-Fi dead zones are, to most of us, a problem solved with guesswork. Your laptop streams just fine in this corner of the bedroom, but not the adjacent one; this arm of the couch is great for uploading photos, but not the other one. You avoid these places, and where the Wi-Fi works becomes a factor in the wear patterns of your home. In an effort to better understand, and possibly eradicate, his Wi-Fi dead zones, one man took the hard way: he solved the Helmholtz equation.

The Helmholtz equation models "the propagation of electronic waves" that involves using a sparse matrix to help minimize the amount of calculation a computer has to do in order to figure out the paths and interferences of waves, in this case from a Wi-Fi router. The whole process is similar to how scattered granular material, like rice or salt, will form complex patterns on top of a speaker depending on where the sound waves are hitting the surfaces.

The author of the post in question, Jason Cole, first solved the equation in two dimensions, and then applied it to his apartment's long and narrow two-bedroom layout. He wrote that he took his walls to have a very high refractive index, while empty space had a refractive index of 1.

Cole found in his simulation he could get pretty good coverage even with his router in one corner of the room, but could get "tendrils of Internet goodness" everywhere if he placed the router right in the center of the apartment. In a simulation where he gave the concrete some absorption potential, he found a map more like what he expected: excellent reception immediately around the router, and beams that shone into various rooms with periodic strong spots from the waves' interference.

When he introduced time to the system, Cole was able to simulate how his apartment might fill with waves over a certain period and eventually become an oscillating standing wave forming pockets of high activity. For instance, the Wi-Fi signal hits a pretty good curve around the doorway into the second bedroom for good reception in a band a couple of feet wide down the center; there's also surprisingly good signal behind a thick wall in the upper right corner of the floor plan.

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Rapid and durable protection against Ebola virus with new experimental ChAd3 Ebola vaccine

Rapid and durable protection against Ebola virus with new experimental ChAd3 Ebola vaccine | Amazing Science |

One shot of an experimental vaccine made from two Ebola virus gene segments incorporated into a chimpanzee cold virus vector (called chimp adenovirus type 3 or ChAd3) protected all four macaque monkeys exposed to high levels of Ebola virus 5 weeks after inoculation, report National Institutes of Health (NIH) scientists and their collaborators.

The ability of the ChAd3 Ebola virus vaccine to elicit rapid protection in monkeys is notable as the world health community battles an ongoing Ebola virus disease outbreak in West Africa. While the protective effects of the single shot waned over time, two out of four inoculated animals were protected when challenged with Ebola virus 10 months after vaccination.

The research team, headed by Nancy J. Sullivan, Ph.D., of the National Institute of Allergy and Infectious Diseases Vaccine Research Center, also demonstrated increased levels of durable protection using an additional vaccine. They inoculated four macaques first with the ChAd3 Ebola vaccine, then 8 weeks later with a booster vaccine containing Ebola virus gene segments incorporated into a different vector (a poxvirus).

Ten months after the initial inoculation, four out of four animals that received both shots were fully protected from infection with high doses of Ebola virus, demonstrating that the prime-boost regimen resulted in durable protection.

The research team included scientists from Okairos, a Swiss-Italian biotechnology company now part of GlaxoSmithKline, and the U.S. Army Medical Research Institute of Infectious Diseases. The experimental ChAd3 Ebola vaccine used in these non-human primate studies is the same one currently being tested in an early-stage human clinical trial at the NIH in Bethesda, Maryland.


  1. Daphne A Stanley, Anna N Honko, Clement Asiedu, John C Trefry, Annie W Lau-Kilby, Joshua C Johnson, Lisa Hensley, Virginia Ammendola, Adele Abbate, Fabiana Grazioli, Kathryn E Foulds, Cheng Cheng, Lingshu Wang, Mitzi M Donaldson, Stefano Colloca, Antonella Folgori, Mario Roederer, Gary J Nabel, John Mascola, Alfredo Nicosia, Riccardo Cortese, Richard A Koup, Nancy J Sullivan.Chimpanzee adenovirus vaccine generates acute and durable protective immunity against ebolavirus challengeNature Medicine, 2014; DOI:10.1038/nm.3702
Vloasis's curator insight, October 8, 2014 7:57 AM

I hope this bodes well.

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First quantum teleportation of multiple properties of a single photon

First quantum teleportation of multiple properties of a single photon | Amazing Science |

Back in 1997, physicists performed an extraordinary experiment that will be forever remembered by researchers and Star Trek fans alike. In this demonstration, the team transported photons from one point in the universe to another without sending them through the space in between — the first successful teleportation in history.

Teleportation is the transfer of the information that describes one object to another object elsewhere in space. In effect, this second object takes on the identity of the first. A more precise description of the team’s experiment with photons is that they transferred the quantum information that describes the polarisation state of one photon to another photon.

Still impressive but not quite the teleportation of the entire photon, which has multiple quantum properties. All of these need to be teleported to recreate it exactly.

Since then, this kind of teleportation has become routine in quantum optics labs all over the world but always with the same limitation. All these experiments involve the transfer of a single quantum property. Nobody has ever found a way to transmit the multiple quantum properties of a single object at the same time and thereby truly teleport it.

Until now. Today, Xi-Lin Wang and buddies at the University of Science and Technology of China in Hefei say they have done just that. The team have worked out how to teleport two quantum properties of a single photon to another photon at the same time — the first time this has ever been done. The work is an important stepping stone towards the ultimate goal of teleporting complex objects such as atoms and small molecules in their entirety.

Most standard teleportation experiments focus on the teleportation of a photon’s polarisation, which is oriented either vertically or horizontally and so is easy to measure. A more complex form of polarisation occurs when the polarisation rotates about the beam axis as the photon propagates.

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The Sound So Loud That It Circled the Earth Four Times

The Sound So Loud That It Circled the Earth Four Times | Amazing Science |

On 27 August 1883, the Earth let out a noise louder than any it has made since.

It was 10:02 AM local time when the sound emerged from the island of Krakatoa, which sits between Java and Sumatra in Indonesia. It was heard 1,300 miles away in the Andaman and Nicobar islands (“extraordinary sounds were heard, as of guns firing”); 2,000 miles away in New Guinea and Western Australia (“a series of loud reports, resembling those of artillery in a north-westerly direction”); and even 3,000 miles away in the Indian Ocean island of Rodrigues, near Mauritius* (“coming from the eastward, like the distant roar of heavy guns.”1) In all, it was heard by people in over 50 different geographical locations, together spanning an area covering a thirteenth of the globe.

Think, for a moment, just how crazy this is. If you’re in Boston and someone tells you that they heard a sound coming from New York City, you’re probably going to give them a funny look. But Boston is a mere 200 miles from New York. What we’re talking about here is like being in Boston and clearly hearing a noise coming from Dublin, Ireland.

Traveling at the speed of sound (766 miles or 1,233 kilometers per hour), it takes a noise about 4 hours to cover that distance. This is the most distant sound that has ever been heard in recorded history.

So what could possibly create such an earth-shatteringly loud bang? A volcano on Krakatoa had just erupted with a force so great that it tore the island apart, emitting a plume of smoke that reached 17 miles into the atmosphere, according to a geologist who witnessed it1. You could use this observation to calculate that stuff spewed out of the volcano at over 1,600 miles per hour—or nearly half a mile per second. That’s more than twice the speed of sound.

This explosion created a deadly tsunami with waves over a hundred feet (30 meters) in height. One hundred sixty-five coastal villages and settlements were swept away and entirely destroyed. In all, the Dutch (the colonial rulers of Indonesia at the time) estimated the death toll at 36,417, while other estimates exceed 120,000.

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New slug flow microextraction technique yields fast results in drug, biomedical testing from single drop of blood

New slug flow microextraction technique yields fast results in drug, biomedical testing from single drop of blood | Amazing Science |

A new technique makes it possible to quickly detect the presence of drugs or to monitor certain medical conditions using only a single drop of blood or urine, representing a potential tool for clinicians and law enforcement.

The technique works by extracting minute quantities of target molecules contained in specimens of blood, urine or other biological fluids, and then testing the sample with a mass spectrometer.

Testing carried out with the technology takes minutes, whereas conventional laboratory methods take hours or days to yield results and require a complex sequence of steps, said Zheng Ouyang, an associate professor in Purdue University's Weldon School of Biomedical Engineering. "We've converted a series of operations into a single extraction process requiring only a pinprick's worth of blood," he said.

The method, called "slug flow microextraction," could be used to detect steroids in urine for drug screening in professional sports and might be combined with a miniature mass spectrometer also being commercialized. The combined technologies could bring a new class of compact instruments for medicine and research, Ouyang said.

Findings are detailed in a paper appeared online Oct. 5 in the research journal Angewandte Chemie International Edition. The paper was authored by graduate student Yue Ren, undergraduate student Morgan N. McLuckey, former postdoctoral research associate Jiangjiang Liu and Ouyang.

The researchers demonstrated the technique, using it to perform therapeutic-drug monitoring, which has potential applications in drug development and personalized therapy; to monitor enzyme function, as demonstrated for acetylcholinesterase, which is directly related to the symptoms and therapy for Alzheimer's disease; to detect steroids, yielding results in one minute; and to test for illicit drugs.

"In the future, for example, parents might be able to test their children's urine for drugs with a simple cartridge they would take to the corner drug store, where a desktop mass spectrometer would provide results in a few minutes," Ouyang said.

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Erasing memory with light: Cortical Representations Are Reinstated by the Hippocampus during Memory Retrieval

Erasing memory with light: Cortical Representations Are Reinstated by the Hippocampus during Memory Retrieval | Amazing Science |

Just look into the light: not quite, but researchers at the UC Davis Center for Neuroscience and Department of Psychology have used light to erase specific memories in mice, and proved a basic theory of how different parts of the brain work together to retrieve episodic memories.

Optogenetics, pioneered by Karl Diesseroth at Stanford University, is a new technique for manipulating and studying nerve cells using light. The techniques of optogenetics are rapidly becoming the standard method for investigating brain function.

Kazumasa Tanaka, Brian Wiltgen and colleagues at UC Davis applied the technique to test a long-standing idea about memory retrieval. For about 40 years, Wiltgen said, neuroscientists have theorized that retrieving episodic memories -- memories about specific places and events -- involves coordinated activity between the cerebral cortex and the hippocampus, a small structure deep in the brain.

"The theory is that learning involves processing in the cortex, and the hippocampus reproduces this pattern of activity during retrieval, allowing you to re-experience the event," Wiltgen said. If the hippocampus is damaged, patients can lose decades of memories.

But this model has been difficult to test directly, until the arrival of optogenetics.

Wiltgen and Tanaka used mice genetically modified so that when nerve cells are activated, they both fluoresce green and express a protein that allows the cells to be switched off by light. They were therefore able both to follow exactly which nerve cells in the cortex and hippocampus were activated in learning and memory retrieval, and switch them off with light directed through a fiber-optic cable.

They trained the mice by placing them in a cage where they got a mild electric shock. Normally, mice placed in a new environment will nose around and explore. But when placed in a cage where they have previously received a shock, they freeze in place in a "fear response."

Tanaka and Wiltgen first showed that they could label the cells involved in learning and demonstrate that they were reactivated during memory recall. Then they were able to switch off the specific nerve cells in the hippocampus, and show that the mice lost their memories of the unpleasant event. They were also able to show that turning off other cells in the hippocampus did not affect retrieval of that memory, and to follow fibers from the hippocampus to specific cells in the cortex.

"The cortex can't do it alone, it needs input from the hippocampus," Wiltgen said. "This has been a fundamental assumption in our field for a long time and Kazu’s data provides the first direct evidence that it is true."

They could also see how the specific cells in the cortex were connected to the amygdala, a structure in the brain that is involved in emotion and in generating the freezing response.

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Aggressive squamous cell carcinoma of skin linked to chronic allergy from metal orthopedic implant

Aggressive squamous cell carcinoma of skin linked to chronic allergy from metal orthopedic implant | Amazing Science |

In rare cases, patients with allergies to metals develop persistent skin rashes after metal devices are implanted near the skin. New research suggests these patients may be at increased risk of an unusual and aggressive form of skin cancer.

Metal alloys help make orthopedic implants stronger and more durable. But people with sensitivity to these metals, which  include nickel, cobalt and chromium, can develop chronic inflammation that promotes the development of skin cancers, report researchers at Washington University School of Medicine and Barnes-Jewish Hospital in St. Louis. The team’s findings were published online Oct. 8 in the Journal of Clinical Investigation.

The researchers were alerted to the connection by a patient who had surgery at another hospital to have a metal rod implanted to repair a fractured ankle. After the surgery, the patient developed a skin rash on her ankle, near the location of the implant. 

The patient turned out to be allergic to nickel in the implant, which led surgeons at the other hospital to remove it. But the rash persisted, and a few years later, a rare form of skin cancer known as Marjolin’s ulcer developed at the surgical site. The cancer, which had become painful and ulcerated, was diagnosed and removed by physicians at Barnes-Jewish Hospital.

The researchers showed in mouse models that chronic skin inflammation caused by continuous skin contact with allergens contributes to tumor development. The finding suggests that patients with metal implants near the skin may need to be monitored for this type of inflammation, according to the researchers. The results likely also will lead to debate and further research on whether physicians should test for metal sensitivity in patients preparing for surgery to get these types of implants.

Chronic inflammation from metal implants can cause joint pain and swelling and contribute to joint failure. And when these implants are placed near the skin, fewer than 5 percent of patients develop an inflammatory rash related to the implant. 

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Two new strange and charming particles discovered at LHC

Two new strange and charming particles discovered at LHC | Amazing Science |

Two new particles have been discovered by the LHCb experiment at CERN's Large Hadron Collider near Geneva, Switzerland. One of them has a combination of properties that has never been observed before.

The particles, named DS3*(2860)– and DS1*(2860)–, are about three times as massive as protons.

Physicists analysed LHCb observations of an energy peak that had been spotted in 2006 by the BaBar experiment at Stanford University in California, but whose cause was still unknown. "Our result shows that the BaBar peak is caused by two new particles," saysTim Gershon of Warwick University, UK, lead author of the discovery.

The force is strong

Mesons are particles that contain two quarks – subatomic particles that make up matter and are thought to be indivisible. These quarks are bound together by the strong force, one of the four fundamental forces that also keeps the constituents of nuclei together within atoms. This force is one of the less well-understood parts of the standard model of particle physics, the incomplete theory that describes how particles interact.

Quarks come in six different flavours known as up, down, strange, charm, bottom and top, in order from lightest to heaviest. The new particles each contain one charm antiquark and one strange quark.

Significantly, DS3*(2860)– also has a spin value of 3, making this discovery the first ever observation of a spin-3 particle containing a charm quark.

In other mesons, the quarks can be configured in one of several different ways to give the particle an overall spin value less than three, and this makes the quarks' exact properties ambiguous. However, for a spin value of three there is no such ambiguity, making DS3*(2860)'s precise configuration clear.

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Spread of multiple myeloma halted in mice: Novel approach now being tested in clinical trials

Spread of multiple myeloma halted in mice: Novel approach now being tested in clinical trials | Amazing Science |

In an advance against cancer metastasis, scientists at the Harvard-affiliated Dana-Farber Cancer Institute have shown that a specially developed compound can impede multiple myeloma in mice from spreading to the bones.

Ghobrial and her team knew that a substance called stromal cell-derived factor-1 (SDF-1) is a kind of protein Pied Piper, attracting certain cells to new locations within the bone marrow. They found that mice with advanced stages of myeloma had sharply higher levels of SDF-1 at the sites in the bones where metastasis had occurred.

“We reasoned that by neutralizing SDF-1, we could change the bone marrow environment to make it less receptive for multiple myeloma cells, reduce myeloma cells’ affinity for the marrow, and thereby inhibit the progression of the disease,” said Aldo Roccaro, the study’s co-first author with Dana-Farber colleague Antonio Sacco.

Working with the German biotechnology company NOXXON Pharma, the researchers tested a substance called olaptesed pegol (a PEGylated mirror-image L-oligonucleotide), which binds tightly and specifically to SDF-1. Laboratory experiments suggested that olaptesed pegol blocked the activity of SDF-1, making it a less alluring signal for tumor cells. In mice, the researchers found that olaptesed pegol altered the bone marrow, rendering it uninviting to myeloma cells. The result was slower disease progression and prolonged survival of the animals.

The findings, published in the Sept. 25 online edition of Cell Reports, suggest the compound may also be able to protect human patients from one of the deadliest effects of cancer.

The research involves a new approach to metastasis, the process by which cancer tumors spread to and colonize distant parts of the body. While traditionally research has focused on the cancer cells themselves, scientists are increasingly studying the interactions between tumor cells and the tissues around them — the so-called microenvironment. In the current study, researchers explored why errant myeloma cells often settle in bones, and whether the bones could be made less hospitable to such malignant homesteading.

“While cure and survival rates have increased for many types of cancers in recent decades, most of these gains have been made in patients with primary cancers — cancers that have not spread beyond their initial site,” said the study’s senior author, Irene Ghobrial of Dana-Farber’s Center for Hematologic Oncology.

“Metastasis remains one of the most formidable complications we face as cancer researchers and physicians. Improvements in the treatment of metastatic cancers have, for the most part, not been nearly as dramatic as in primary disease.”

The current study focused on multiple myeloma because it is metastatic by nature. Myeloma cells originate in the bone marrow, depart for the bloodstream, and eventually return to the bones, where they form numerous colonies — hence the name.

A Spiegelmer® is a mirror-image oligonucleotide that can bind to a pharmacologically relevant target molecule in a manner conceptually similar to an antibody that recognizes an antigen. The mirror image configuration of the oligonucleotide confers tremendous stability in all biological environments, as naturally occurring nucleases cannot degrade Spiegelmers.

Identification of Spiegelmers involves screening of extremely large combinatorial libraries containing over 1e15 different molecules. NOXXON’s technology combines the SELEX process (Systematic Evolution of Ligands by EXponential Enrichment) – the method to screen such a library – with chemical mirroring technology (see flash animation). Employing NOXXON’s technology Spiegelmers® can be rapidly generated against a wide variety of target molecules.

Unlike antibodies Spiegelmer are chemical entities unknown to nature and do not require complex biological production processes. Instead Spiegelmers can be synthesized in the laboratory using a process that is easily scalable. NOXXON has established optimized production and quality control methods.

Spiegelmers possess the high affinity binding characteristics of the best aptamers and antibodies in the low nanomolar and picomolar range, while defying enzymatic degradation that severely limits the utility of aptamers. Data indicate that Spiegelmers are stable in human plasma for over 60 hours at 37 °C.

Spiegelmers should not be confused with antisense RNAs in that they do not directly interfere with protein synthesis of their target molecules. They are designed to bind specifically to extracellular molecules, either a receptor or its ligand, similar to the behavior of a monoclonal antibody, aptamer or peptide. However, recent findings by NOXXON demonstrate that Spiegelmers are capable of entering cells and interfering with intracellular processes as well.

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WHO: What we know about transmission of the Ebola virus among humans

WHO: What we know about transmission of the Ebola virus among humans | Amazing Science |
Ebola virus disease is not an airborne infection. Airborne spread among humans implies inhalation of an infectious dose of virus from a suspended cloud of small dried droplets.

This mode of transmission has not been observed during extensive studies of the Ebola virus over several decades.

Common sense and observation tell us that spread of the virus via coughing or sneezing is rare, if it happens at all. Epidemiological data emerging from the outbreak are not consistent with the pattern of spread seen with airborne viruses, like those that cause measles and chickenpox, or the airborne bacterium that causes tuberculosis.

Theoretically, wet and bigger droplets from a heavily infected individual, who has respiratory symptoms caused by other conditions or who vomits violently, could transmit the virus – over a short distance – to another nearby person.

This could happen when virus-laden heavy droplets are directly propelled, by coughing or sneezing (which does not mean airborne transmission) onto the mucus membranes or skin with cuts or abrasions of another person.

WHO is not aware of any studies that actually document this mode of transmission. On the contrary, good quality studies from previous Ebola outbreaks show that all cases were infected by direct close contact with symptomatic patients.

The Ebola virus is transmitted among humans through close and direct physical contact with infected bodily fluids, the most infectious being blood, feces and vomit.

The Ebola virus has also been detected in breast milk, urine and semen. In a convalescent male, the virus can persist in semen for at least 70 days; one study suggests persistence for more than 90 days.

Saliva and tears may also carry some risk. However, the studies implicating these additional bodily fluids were extremely limited in sample size and the science is inconclusive. In studies of saliva, the virus was found most frequently in patients at a severe stage of illness. The whole live virus has never been isolated from sweat.

The Ebola virus can also be transmitted indirectly, by contact with previously contaminated surfaces and objects. The risk of transmission from these surfaces is low and can be reduced even further by appropriate cleaning and disinfection procedures.

NIH Ebola Information

Eric Chan Wei Chiang's curator insight, October 10, 2014 2:39 AM

These are some really good facts about the current Ebola outbreak.


Local authorities in affected countries are making creative use of ICT to help fight Ebola


More scoops on Ebola can be read here:

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Nobel Prize 2014 in Chemistry given for circumventing a basic law of physics, pushing the limits of microscopes

Nobel Prize 2014 in Chemistry given for circumventing a basic law of physics, pushing the limits of microscopes | Amazing Science |

Three scientists, two American and one German, received this year’s Nobel Prize in Chemistry for circumventing a basic law of physics and enabling microscopes to peer at the tiniest structures within living cells.

The 2014 laureates, announced Wednesday by the Royal Swedish Academy of Sciences, are Eric Betzig, 54, of the Howard Hughes Medical Institute in Virginia; Stefan W. Hell, 51, of the Max Planck Institute for Biophysical Chemistry in Germany; and William E. Moerner, 61, of Stanford University in California.

For centuries, optical microscopes — those that magnify ordinary visible light — have allowed biologists to study organisms too small to be seen with the naked eye. But a fundamental law of optics known as the diffraction limit, first described in 1873, states that the resolution can never be better than half the wavelength of light being looked at.

For visible light, that limit is about 0.2 millionths of a meter, or one-127,000th of an inch. A human hair is 500 times as wide. But a bacterium is not much larger than the size of the diffraction limit, and there was little hope of seeing details within the cell like the interaction of individual proteins. Other technology like the electron microscope, which generates images from beams of electrons instead of particles of light, achieves higher resolution, but it has other limitations, like requiring the sample to be sliced thin and placed in a vacuum. For biological research, that generally meant the subject of study had to be dead.

At first glance, circumventing the diffraction limit would seem a foolish pursuit, like trying to invent a perpetual motion machine or faster-than-light travel — doomed by fundamental limits on how the universe works. Nonetheless, Dr. Hell, who was born in Romania, started working on the problem after finishing his doctorate at the University of Heidelberg in 1990. After failing to find financing in Germany to pursue his ideas, he obtained a research position at the University of Turku in Finland in 1993. A year later, he published his theoretical proposal for achieving sharper microscopic pictures.

Dr. Hell’s insight was that by using lasers, he could restrict the glow to a very small section. That way, for structures smaller than the diffraction limit, “You can tell them apart just by making sure that one of them is off when the other is on,” he said in an interview.

Other scientists could have just taken his proposal and made it work in the laboratory long before he did, he said, adding: “I was a sort of nobody in those days. I didn’t even have a lab, really. People could have taken it as a recipe, could have done it. But they didn’t do it. Why didn’t they do it? Because they thought it wouldn’t work that way.”

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Creating low-cost solar energy on bendable plastic films

Creating low-cost solar energy on bendable plastic films | Amazing Science |
Work by PhD student Alex Barker, under the supervision of Dr Justin Hodgkiss, a senior lecturer in the School of Chemical and Physical Sciences, is helping to improve the efficiency of next generation solar cells made from materials like plastics.

The research, published recently by the prestigious international Journal of the American Chemical Society, addresses the long-standing question of how light produces charge pairs far enough apart from each other that they are free to flow as current, rather than staying bound together and ultimately just releasing heat.

The technique used by the researchers was to freeze the solar cells to -263 degrees Celsius, where charge pairs get stuck together. They then used lasers to measure the how far apart they moved as the temperatures increase.

"We found that the efficiency of polymer, or plastic-based, solar cell is determined by the ability of charge pairs to rapidly escape from each other while they are still 'hot' from the light energy," says Dr Hodgkiss, a 2011 Rutherford Discovery Fellow.

He adds that understanding how plastic solar cells work will result in more efficient and cheaper conductive materials that overcome the limitations of conventional solar cells.

"Because they're plastic and flexible, they could be rolled out to cover a tent or used as semi-transparent filters on windows."

The findings of the research settle a long-standing debate about how polymer solar cells work, and offers potential to guide the design of cheaper and more efficient materials, by isolating the key step in their development.

Ms. Moon's curator insight, October 9, 2014 10:29 PM

Materials Science is a fascinating subject. Here someone thought outside conventional wisdom and created something new and better. That's what "innovation" is all about.

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Introducing multifunctional theranostic nanoparticles with combined diagnostic and therapeutic functions

Introducing multifunctional theranostic nanoparticles with combined diagnostic and therapeutic functions | Amazing Science |

Multifunctional nanoparticles with combined diagnostic and therapeutic functions (so called theranostics) show great promise towards personalized nanomedicine. However, attaining consistently high performance of these functions in vivo in one single nanoconstruct remains extremely challenging. A group of scientists now demonstrate the use of one single polymer to develop a smart ‘all-in-one’ nanoporphyrin platform that conveniently integrates a broad range of clinically relevant functions. Nanoporphyrins can be used as amplifiable multimodality nanoprobes for near-infrared fluorescence imaging (NIRFI), magnetic resonance imaging (MRI), positron emission tomography (PET) and dual modal PET-MRI. Nanoporphyrins greatly increase the imaging sensitivity for tumor detection through background suppression in blood, as well as preferential accumulation and signal amplification in tumors. Nanoporphyrins also function as multiphase nanotransducers that can efficiently convert light to heat inside tumours for photothermal therapy (PTT), and light to singlet oxygen for photodynamic therapy (PDT). Furthermore, nanoporphyrins act as programmable releasing nanocarriers for targeted delivery of drugs or therapeutic radio-metals into tumors.

essica Tucker, program director of Drug and Gene Delivery and Devices at the National Institute of Biomedical Imaging and Bioengineering, which is part of the National Institutes of Health, said the approach outlined in the study has the ability to combine both imaging and therapeutic applications in a single platform, which has been difficult to achieve, especially in an organic, and therefore biocompatible, vehicle.

"This is especially valuable in cancer treatment, where targeted treatment to tumor cells, and the reduction of lethal effects in normal cells, is so critical," she added.

Though not the first nanoparticles, these may be the most versatile. Other particles are good at some tasks but not others. Non-organic particles, such as quantum dots or gold-based materials, work well as diagnostic tools but have safety issues. Organic probes are biocompatible and can deliver drugs but lack imaging or phototherapy applications.

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Boundary Dam Power Plant: Let the Clean Coal Era Begin

Boundary Dam Power Plant: Let the Clean Coal Era Begin | Amazing Science |

On October 2, the Boundary Dam power plant in Saskatchewan became the first full-sized coal-fired boiler tocapture the copious carbon dioxide that had previously billowed from its smokestack, preventing the greenhouse gas from entering the atmosphere. On the resulting invisible stream of hot smoke ride the hopes of combating climate change while still burning fossil fuels.

Such CO2 capture and storage (CCS) “is the only known technology that will enable us to continue to use fossil fuels and also de-carbonize the energy sector,” said Maria van der Hoeven, executive director of the International Energy Agency, in a statement on the opening of the Boundary Dam plant. “As fossil fuel consumption is expected to continue for decades, deployment of CCS is essential.”

That deployment is beginning to happen in fits and starts, and with lots of government support. For example, the Mississippi-based Kemper Facility, a power plant that will turn brown coal to gas and strip off the CO2 in the process, is due online in 2015—a year behind schedule and at a of cost $5.6 billion, more than twice its initial estimate. And the U.S. Environmental Protection Agency has approved plans by Archer Daniels Midland (ADM) to inject CO2 captured at its ethanol fermentation facility in Illinois into a saltwater aquifer deep underground.

The Boundary Dam also burns brown coal, the most polluting form of the most polluting fossil fuel. Saskatchewan has an estimated 300-year supply of the dirty fuel to burn at present rates of consumption. The unit uses amines—a nitrogen-based molecule that can bond with CO2—to capture a projected 1 million metric tons of the leading greenhouse gas each year. The amine captures the CO2 and then when further heated releases it again, meaning it takes away some of the plant’s power to take away the plant’s CO2. The captured CO2, compressed and liquefied, will then travel 66 kilometers via pipeline to the nearby Weyburn oil fields and join the CO2 captured at a plant that turns brown coal into a gas in North Dakota. At Weyburn, the CO2 will be used to scour more oil out of the ground. Of course, the eventual burning of this oil will also release CO2 into the atmosphere.

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First Maxwell's Demon Incarnated In A Real, Single-Electron Szilard Engine

First Maxwell's Demon Incarnated In A Real, Single-Electron Szilard Engine | Amazing Science |

Scientists have physically realized a microscopic, single electron Szilard engine, a construction formerly of only theoretical design created by the physicist Leo Szilard and based on “Maxwell’s demon”.  As originally conceived in 1929, the Szilard engine apparently violates the laws of thermodynamics, allowing work to be extracted from energy of the surroundings in the absence of temperature and pressure gradients.  But careful measurement of heat released and absorbed in the study showed perfect accounting of energies, in accordance with the theoretical amount as predicted by physicist Rolf Landauer.

The researchers created a microscopic engine very close to the original Maxwell demon and the Szilard engine.  Instead of a particle, the degree of freedom is a charge distribution with an extra electron sloshing in a contained system.  Instead of two halves of a box in which to trap the particle, there are two conductive “islands” which hold the electron charge.

When the electron tunnels back and forth it is like the particle bouncing from one side to the next.  Instead of a partition dividing the confined space for the particle, a gate voltage biases the charge toward one of the islands which when released slowly gives up work as the electron tunnels to the other side again.  And finally, instead of a demon deciding how to partition the confined space with a piston, an electronics circuit detects which side the electron is on in order to apply the gate voltage at the right time.  Because there are only two states the electron can be in, one for each island, the net information from the detector determining the electron’s position is 1 bit.

The researchers ran the engine for hundreds of cycles, averaging their measurements of the heat absorbed and emitted.  The result matched exactly Rolf Landauer’s prediction that the energy of 1 bit of information costs kT ln 2.  Repeat measurements are needed as deriving macroscopic quantities like heat from microscopic observations requires what is known as ensemble averaging.

The Szilard engine is based on the Maxwell Demon, which itself is another theoretical construct originally conceived by James Maxwell to sharpen his understanding of two theories: thermodynamics, the macroscopic theory of heat, energy and work, and statistical mechanics, the corresponding microscopic theory.  In his demon, Maxwell found a way to apparently violate the Second Law of thermodynamics. The small demon, by observing the a confined set of particles, by virtue of its intelligence is able to segregate the particles faster than average from those slower, apparently violating the 2nd Law of thermodynamics.

In Szilard’s engine, a refinement of the Maxwell demon idea, depending on which side of the container the particle is at any moment in time, the demon sets up a piston that moves in the opposing direction, an action costing arbitrarily little energy with proper design.  The particle then performs work as it exerts pressure on the piston pushing it back out to equilibrium.  The particle loses energy and gives it up for doing work on the piston, in apparent contradiction to the Second Law.  Richard Feynman describes a similar “Brownian” ratchet which also seems to convert the ambient energy of environment into directed ratcheting action.

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Scientists identify more than 400 genetic regions that influence height

Scientists identify more than 400 genetic regions that influence height | Amazing Science |

The researchers say their findings, reached by analyzing genome-wide data from more than 250,000 people, can explain around 20% of height heritability in humans, increasing from 12% prior to this study.

"The study also narrows down the genomic regions that contain a substantial proportion of remaining variation - to be discovered with even larger sample sizes," says co-senior investigator Peter Visscher, PhD, of the University of Queensland in Australia.

The researchers publish their findings in the journal Nature Genetics.

Height is a model characteristic for determining the mechanisms behind human genetics, according to the investigators. It particularly helps improve understanding of traits that are produced by multiple genes. They note that height is simple to measure, and approximately 80% of height variation is genetic. The remaining 20% is thought to be influenced by environmental and lifestyle factors.

Previous studies have suggested that height is influenced by lots of genes, most of which come from common genetic variants rather than rare ones. But the investigators involved in this latest research say that these studies have not been large enough to confirm such findings.

697 genetic variants in 424 genetic regions linked to height

With this in mind, the researchers set up the Genetic Investigation of Anthropometric Traits (GIANT) Consortium. This involved analyzing the genomic data of 253,288 individuals from more than 300 worldwide institutions.

The team searched approximately 2 million genetic variants that were present in at least 5% of participants. From this, they identified 697 genetic variants located in 424 genetic regions that were linked to height.

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