High milk intake linked with higher fractures and mortality, research suggests

Women who drank more than three glasses of milk a day had a higher risk of death than women who drank less than one glass of milk a day. Credit: © Africa Studio / Fotolia
Women who drank more than three glasses of milk a day had a higher risk of death than women who drank less than one glass of milk a day.
Credit: © Africa Studio / Fotolia

[dropcap]A[/dropcap] high milk intake in women and men is not accompanied by a lower risk of fracture and instead may be associated with a higher rate of death, suggests observational research published in The BMJ this week.

This may be explained by the high levels of lactose and galactose (types of sugar) in milk, that have been shown to increase oxidative stress and chronic inflammation in animal studies, say the researchers.

However, they point out that their study can only show an association and cannot prove cause and effect. They say the results “should be interpreted cautiously” and further studies are needed before any firm conclusions or dietary recommendations can be made.

A diet rich in milk products is promoted to reduce the likelihood of osteoporotic fractures, but previous research looking at the importance of milk for the prevention of fractures and the influence on mortality rates show conflicting results.

So a research team in Sweden, led by Professor Karl Michaëlsson, set out to examine whether high milk intake may increase oxidative stress, which, in turn, affects the risk of mortality and fracture.

Two large groups of 61,433 women (aged 39-74 years in 1987-1990) and 45,339 men (aged 45-79 years in 1997) in Sweden completed food frequency questionnaires for 96 common foods including milk, yoghurt and cheese.

Lifestyle information, weight and height were collated and factors such as education level and marital status were also taken into account. National registers were used to track fracture and mortality rates.

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Women were tracked for an average of 20 years, during which time 15,541 died and 17,252 had a fracture, of whom 4,259 had a hip fracture.

In women, no reduction in fracture risk with higher milk consumption was observed. Furthermore, women who drank more than three glasses of milk a day (average 680 ml) had a higher risk of death than women who drank less than one glass of milk a day (average 60 ml).

Men were tracked for an average of 11 years, during which time 10,112 died and 5,066 had a fracture, with 1,166 hip fracture cases. Men also had a higher risk of death with higher milk consumption, although this was less pronounced than in women.

Further analysis showed a positive association between milk intake and biomarkers of oxidative stress and inflammation.

In contrast, a high intake of fermented milk products with a low lactose content (including yoghurt and cheese) was associated with reduced rates of mortality and fracture, particularly in women.

They conclude that a higher consumption of milk in women and men is not accompanied by a lower risk of fracture and instead may be associated with a higher rate of death. Consequently, there may be a link between the lactose and galactose content of milk and risk, although causality needs be tested.

“Our results may question the validity of recommendations to consume high amounts of milk to prevent fragility fractures,” they write. “The results should, however, be interpreted cautiously given the observational design of our study. The findings merit independent replication before they can be used for dietary recommendations.”

Michaëlsson and colleagues raise a fascinating possibility about the potential harms of milk, says Professor Mary Schooling at City University of New York in an accompanying editorial. However, she stresses that diet is difficult to assess precisely and she reinforces the message that these findings should be interpreted cautiously.

“As milk consumption may rise globally with economic development and increasing consumption of animal source foods, the role of milk and mortality needs to be established definitively now,” she concludes.

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Story Source:

The above story is based on materials provided by BMJ-British Medical Journal.Note: Materials may be edited for content and length.


Journal References:

  1. K. Michaelsson, A. Wolk, S. Langenskiold, S. Basu, E. Warensjo Lemming, H. Melhus, L. Byberg. Milk intake and risk of mortality and fractures in women and men: cohort studies. BMJ, 2014; 349 (oct27 1): g6015 DOI:10.1136/bmj.g6015
  2. C. M. Schooling. Milk and mortality. BMJ, 2014; 349 (oct27 1): g6205 DOI:10.1136/bmj.g6205

Imaging electric charge propagating along microbial nanowires

UMass Amherst researchers recently provided stronger evidence than ever before to support their claim that the microbe Geobacter produces tiny electrical wires, called microbial nanowires, along which electric charges propagate just as they do in carbon nanotubes, a highly conductive human-made material. Credit: UMass Amherst
UMass Amherst researchers recently provided stronger evidence than ever before to support their claim that the microbe Geobacter produces tiny electrical wires, called microbial nanowires, along which electric charges propagate just as they do in carbon nanotubes, a highly conductive human-made material.
Credit: UMass Amherst

The claim by microbiologist Derek Lovley and colleagues at the University of Massachusetts Amherst that the microbe Geobacter produces tiny electrical wires, called microbial nanowires, has been mired in controversy for a decade, but the researchers say a new collaborative study provides stronger evidence than ever to support their claims.

UMass Amherst physicists working with Lovley and colleagues report in the current issue of Nature Nanotechnology that they’ve used a new imaging technique, electrostatic force microscopy (EFM), to resolve the biological debate with evidence from physics, showing that electric charges do indeed propagate along microbial nanowires just as they do in carbon nanotubes, a highly conductive human-made material.

Physicists Nikhil Malvankar and Sibel Ebru Yalcin, with physics professor Mark Tuominen, confirmed the discovery using EFM, a technique that can show how electrons move through materials. “When we injected electrons at one spot in the microbial nanowires, the whole filament lit up as the electrons propagated through the nanowire,” says Malvankar.

Yalcin, now at Pacific Northwest National Lab, adds, “This is the same response that you would see in a carbon nanotube or other highly conductive synthetic nanofilaments. Even the charge densities are comparable. This is the first time that EFM has been applied to biological proteins. It offers many new opportunities in biology.”

Lovley says the ability of electric current to flow through microbial nanowires has important environmental and practical implications. “Microbial species electrically communicate through these wires, sharing energy in important processes such as the conversion of wastes to methane gas. The nanowires permit Geobacter to live on iron and other metals in the soil, significantly changing soil chemistry and playing an important role in environmental cleanup. Microbial nanowires are also key components in the ability of Geobacter to produce electricity, a novel capability that is being adapted to engineer microbial sensors and biological computing devices.”

He acknowledges that there has been substantial skepticism that Geobacter’s nanowires, which are protein filaments, could conduct electrons like a wire, a phenomenon known as metallic-like conductivity. “Skepticism is good in science, it makes you work harder to evaluate whether what you are proposing is correct,” Lovley points out. “It’s always easier to understand something if you can see it. Drs. Malvankar and Yalcin came up with a way to visualize charge propagation along the nanowires that is so elegant even a biologist like me can easily grasp the mechanism.”

Biologists have known for years that in biological materials, electrons typically move by hopping along discrete biochemical stepping-stones that can hold the individual electrons. By contrast, electrons in microbial nanowires are delocalized, not associated with just one molecule. This is known as metallic-like conductivity because the electrons are conducted in a manner similar to a copper wire.

Malvankar, who provided the first evidence for the metallic-like conductivity of the microbial nanowires in Lovley and Tuominen’s labs in 2011, says, “Metallic-like conductivity of the microbial nanowires seemed clear from how it changed with different temperature or pH, but there were still many doubters, especially among biologists.”

To add more support to their hypothesis, Lovley’s lab genetically altered the structure of the nanowires, removing the aromatic amino acids that provide the delocalized electrons necessary for metallic-like conductivity, winning over more skeptics. But EFM provides the final, key evidence, Malvankar says.

“Our imaging shows that charges flow along the microbial nanowires even though they are proteins, still in their native state attached to the cells. Seeing is believing. To be able to visualize the charge propagation in the nanowires at a molecular level is very satisfying. I expect this technique to have an especially important future impact on the many areas where physics and biology intersect.” he adds.

Tuominen says, “This discovery not only puts forward an important new principle in biology but also in materials science. Natural amino acids, when arranged correctly, can propagate charges similar to molecular conductors such as carbon nanotubes. It opens exciting opportunities for protein-based nanoelectronics that was not possible before.”

Lovley and colleagues’ microbial nanowires are a potential “green” electronics component, made from renewable, non-toxic materials. They also represent a new part in the growing field of synthetic biology, he says. “Now that we understand better how the nanowires work, and have demonstrated that they can be genetically manipulated, engineering ‘electric microbes’ for a diversity of applications seems possible.”

One application currently being developed is making Geobacter into electronic sensors to detect environmental contaminants. Another is Geobacter-based microbiological computers. This work was supported by the Office of Naval Research, the U.S. Department of Energy and the National Science Foundation.


Story Source:

The above story is based on materials provided by University of Massachusetts at Amherst. Note: Materials may be edited for content and length.


Journal Reference:

  1. Nikhil S. Malvankar, Sibel Ebru Yalcin, Mark T. Tuominen, Derek R. Lovley.Visualization of charge propagation along individual pili proteins using ambient electrostatic force microscopy. Nature Nanotechnology, 2014; DOI:10.1038/nnano.2014.236

Electric vehicle technology packs more punch in smaller package

ORNL's 30-kilowatt power inverter offers greater reliability and power in a compact package. Credit: ORNL
ORNL’s 30-kilowatt power inverter offers greater reliability and power in a compact package.
Credit: ORNL

[dropcap]U[/dropcap]sing 3-D printing and novel semiconductors, researchers at the Department of Energy’s Oak Ridge National Laboratory have created a power inverter that could make electric vehicles lighter, more powerful and more efficient.

At the core of this development is wide bandgap material made of silicon carbide with qualities superior to standard semiconductor materials. Power inverters convert direct current into the alternating current that powers the vehicle. The Oak Ridge inverter achieves much higher power density with a significant reduction in weight and volume.

“Wide bandgap technology enables devices to perform more efficiently at a greater range of temperatures than conventional semiconductor materials,” said ORNL’s Madhu Chinthavali, who led the Power Electronics and Electric Machinery Group on this project. “This is especially useful in a power inverter, which is the heart of an electric vehicle.”

Specific advantages of wide bandgap devices include: higher inherent reliability; higher overall efficiency; higher frequency operation; higher temperature capability and tolerance; lighter weight, enabling more compact systems; and higher power density.

Additive manufacturing helped researchers explore complex geometries, increase power densities, and reduce weight and waste while building ORNL’s 30-kilowatt prototype inverter.

“With additive manufacturing, complexity is basically free, so any shape or grouping of shapes can be imagined and modeled for performance,” Chinthavali said. “We’re very excited about where we see this research headed.”

Using additive manufacturing, researchers optimized the inverter’s heat sink, allowing for better heat transfer throughout the unit. This construction technique allowed them to place lower-temperature components close to the high-temperature devices, further reducing the electrical losses and reducing the volume and mass of the package.

Another key to the success is a design that incorporates several small capacitors connected in parallel to ensure better cooling and lower cost compared to fewer, larger and more expensive “brick type” capacitors.

The research group’s first prototype, a liquid-cooled all-silicon carbide traction drive inverter, features 50 percent printed parts. Initial evaluations confirmed an efficiency of nearly 99 percent, surpassing DOE’s power electronics target and setting the stage for building an inverter using entirely additive manufacturing techniques.

Building on the success of this prototype, researchers are working on an inverter with an even greater percentage of 3-D printed parts that’s half the size of inverters in commercially available vehicles. Chinthavali, encouraged by the team’s results, envisions an inverter with four times the power density of their prototype.

Others involved in this work, which was to be presented today at the Second Institute of Electrical and Electronics Engineers Workshop on Wide Bandgap Power Devices and Applications in Knoxville, were Curt Ayers, Steven Campbell, Randy Wiles and Burak Ozpineci.

Research for this project was conducted at ORNL’s National Transportation Research Center and Manufacturing Demonstration Facility, DOE user facilities, with funding from DOE’s Office of Energy Efficiency and Renewable Energy.


Story Source:

The above story is based on materials provided by Oak Ridge National Laboratory.Note: Materials may be edited for content and length.

Scientists create new protein-based material with some nerve

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[dropcap]S[/dropcap]cientists at the University of California, Berkeley, have taken proteins from nerve cells and used them to create a “smart” material that is extremely sensitive to its environment. This marriage of materials science and biology could give birth to a flexible, sensitive coating that is easy and cheap to manufacture in large quantities.

The work, to be published Oct. 14, in the journal Nature Communications, could lead to new types of biological sensors, flow valves and controlled drug release systems, the researchers said. Biomedical applications include microfluidic devices that can handle and process very small volumes of liquid, such as samples of saliva or blood, for diagnostics.

“This work represents a unique convergence of the fields of biomimetic materials, biomolecular engineering and synthetic biology,” said principal investigator Dr. Sanjay Kumar, UC Berkeley associate professor of bioengineering. “We created a new class of smart, protein-based materials whose structural principles are inspired by networks found in living cells.”

Kumar’s research team set out to create a biological version of a synthetic coating used in everyday liquid products, such as paint and liquid cosmetics, to keep small particles from clumping together. The synthetic coatings are often called polymer brushes because of their bristle-like appearance when attached to the particle surface.

To create the biological equivalent of a polymer brush, the researchers turned to neurofilaments, pipe cleaner-shaped proteins found in nerve cells. By acting as tiny, cylindrical polymer brushes, neurofilaments collectively assemble into a structural network that helps keep one end of the nerve cell propped open so that it can conduct electrical signals.

“We co-opted this protein and turned it into a polymer brush by cloning a portion of a gene that encodes one of the neurofilament bristles, re-engineering it such that we could attach the resulting protein to surfaces in a precise and oriented way, and then expressing the gene in bacteria to produce the protein in large, pure quantities,” said Kumar. “We showed that our ‘protein brush’ had all the key properties of synthetic brushes, plus a number of advantages.”

Kumar noted that neurofilaments are good candidates for protein brushes because they are intrinsically disordered proteins, so named because they don’t have a fixed 3-D shape. The size and chemical sequence of these hair-like proteins are far easier to control when compared with their synthetic counterparts.

“In biology, precision is critical,” said Kumar. “Proteins are generally synthesized with the exact same sequence every time; the length and biochemical order of the protein sequence affects all of its properties, including structure and the ability to bind to other molecules and catalyze biochemical reactions. This kind of sequence precision is difficult if not impossible to achieve in the laboratory using the tools of chemical synthesis. By harnessing the precision of biology and letting the bacterial cell do all the work for us, we were able to control the exact length and sequence of the bristles of our protein brush.”

The researchers showed that the protein brushes could be grafted onto surfaces, and that they dramatically expand and collapse in reaction to changes in acidity and salinity. Materials that are environmentally sensitive in this way are often referred to as “smart” materials because of their ability to adaptively respond to specific stimuli.


Story Source:

The above story is based on materials provided by University of California – Berkeley. The original article was written by Sarah Yang. Note: Materials may be edited for content and length.


Journal Reference:

  1. Nithya Srinivasan, Maniraj Bhagawati, Badriprasad Ananthanarayanan, Sanjay Kumar. Stimuli-sensitive intrinsically disordered protein brushes. Nature Communications, 2014; 5: 5145 DOI: 10.1038/ncomms6145

Is matter falling into the massive black hole at the center of the Milky Way or being ejected from it?

This composite of Sagittarius A-Star combines radio images from the NRAO Very Large Array (green), BIMA (red) and the NASA Spitzer Space Telescope (blue). Credit: Image courtesy of NRAO/AUI
This composite of Sagittarius A-Star combines radio images from the NRAO Very Large Array (green), BIMA (red) and the NASA Spitzer Space Telescope (blue).
Credit: Image courtesy of NRAO/AUI

[dropcap]I[/dropcap]s matter falling into the massive black hole at the center of the Milky Way or being ejected from it? No one knows for sure, but a UC Santa Barbara astrophysicist is searching for an answer.

Carl Gwinn, a professor in UCSB’s Department of Physics, and colleagues have analyzed images collected by the Russian spacecraft RadioAstron. Their findings appear in the current issue of The Astrophysical Journal Letters.

RadioAstron was launched into orbit from Baikonur, Kazakhstan, in July 2011 with several missions, one of which was to investigate the scattering of pulsars — the cores of dead stars — by interstellar gas. What the team found led them to examine additional observations of Sagittarius A-Star (A*), the source that marks the Milky Way’s central black hole. Sagittarius A* is visible at radio, infrared and X-ray wavelengths.

This massive black hole — which contains 4 million solar masses — does not emit radiation but is visible from the gas around it. The gas is being acted upon by the black hole’s very strong gravitational field. The wavelengths that make Sagittarius A* visible are scattered by interstellar gas along the line of sight in the same way that light is scattered by fog on Earth.

Gwinn and his colleagues found that the images taken by RadioAstron contained small spots. “I was quite surprised to find that the effect of scattering produced images with small lumps in the overall smooth image,” explained Gwinn. “We call these substructure. Some previous theories had predicted similar effects in the 1980s, and a quite controversial observation in the 1970s had hinted at their presence.”

In order to better understand the substructure, Michael Johnson, Gwinn’s former graduate student now at the Harvard-Smithsonian Center for Astrophysics, conducted theoretical research. He realized that the anomalies could be used to infer the actual size of the underlying source.

Additional observations made using the Very Long Baseline Array — an interferometer consisting of 10 identical antennas distributed across the United States — and the 100-meter Green Bank Telescope in West Virginia showed the presence of lumps in the image of Sagittarius A*. Recent upgrades have greatly increased the sensitivity of these telescopes. Even so, evidence of the lumps, or substructure, remained extremely faint.

“The theory and observations allow us to make statements about the interstellar gas responsible for the scattering, and about the emission region around the black hole,” Johnson said. “It turns out that the size of that emission region is only 20 times the diameter of the event horizon as it would be seen from Earth. With additional observations, we can begin to understand the behavior in this extreme environment.”

While no scientific team has been able to produce a complete image of the black hole’s emission, astronomers have drawn inferences about scattering properties from observations at longer wavelengths. “From these they can extrapolate those properties to 1 centimeter and use that to make a rough estimate of the size of the source,” Gwinn said. “We seem to agree quite well with that estimate.”

Not only did Gwinn and his colleagues directly confirm these indirect inferences about the size of Sagittarius A*, they were also able to provide new information about fluctuations in the interstellar gas that cause scattering. Their work shows that the spectrum of interstellar turbulence is shallow.

“There are different ways of interpreting observations of the scattering, and we showed that one of them is right and the others are wrong,” said co-investigator Yuri Kovalev, the RadioAstron project scientist. “This will be important for future research on the gas near this black hole. This work is a good example of the synergy between different modern research infrastructures, technologies and science ideas.”

A friendly international race is going on to see who will be the first to image the black hole’s emissions and thereby determine whether gas falls into the black hole or is being ejected in the form of a jet.

“The character of the substructure seems to be random, so we are keen to go back and confirm the statistics of our sample with more data,” Gwinn said. “We’re also interested in looking at shorter wavelengths where we think the emission region may be smaller and we can get closer to the black hole. We may be able to extract more information than just the size of the emission region. We might possibly be able to make a simple image of how matter falls into a black hole or is ejected from it. It would be very exciting to produce such an image.”


Story Source:

The above story is based on materials provided by University of California – Santa Barbara. The original article was written by Julie Cohen. Note: Materials may be edited for content and length.


Journal Reference:

  1. C. R. Gwinn, Y. Y. Kovalev, M. D. Johnson, V. A. Soglasnov. DISCOVERY OF SUBSTRUCTURE IN THE SCATTER-BROADENED IMAGE OF SGR A*. The Astrophysical Journal, 2014; 794 (1): L14 DOI: 10.1088/2041-8205/794/1/L14

FYI: Why Do Clouds Stay Up?

A cloud is made up of liquid water droplets. A cloud forms when air is heated by the sun. As it rises, it slowly cools it reaches the saturation point and water condenses, forming a cloud. As long as the cloud and the air that its made of is warmer than the outside air around it, it floats!

Watch this video for better understanding of “Why Do Clouds Stay Up?

 

Rising sea levels of 1.8 meters in worst-case scenario, researchers calculate

The worst-case sea level projections is shown in red. There is 95% certainty that sea level will not rise faster than this upper-limit. Purple shows the likely range of sea level rise as projected in the IPCC fifth assessment report under a scenario with rising emissions throughout the 21st century (RCP8.5). Credit: Aslak Grinsted, NBI
The worst-case sea level projections is shown in red. There is 95% certainty that sea level will not rise faster than this upper-limit. Purple shows the likely range of sea level rise as projected in the IPCC fifth assessment report under a scenario with rising emissions throughout the 21st century (RCP8.5).
Credit: Aslak Grinsted, NBI

[dropcap]T[/dropcap]he climate is getting warmer, the ice sheets are melting and sea levels are rising — but how much? The report of the UN’s Intergovernmental Panel on Climate Change (IPCC) in 2013 was based on the best available estimates of future sea levels, but the panel was not able to come up with an upper limit for sea level rise within this century. Now researchers from the Niels Bohr Institute and their colleagues have calculated the risk for a worst-case scenario. The results indicate that at worst, the sea level would rise a maximum of 1.8 meters.

The results are published in the scientific journal Environmental Research Letters.

What causes the sea to rise is when all the water that is now frozen as ice and lies on land melts and flows into the sea. It is first and foremost about the two large, kilometer-thick ice sheets on Greenland and Antarctica, but also mountain glaciers.

In addition, large amounts of groundwater is pumped for both drinking water and agricultural use in many parts of the world and more groundwater is pumped than seeps back down into the ground, so this water also ends up in the oceans.

Finally, what happens is that when the climate gets warmer, the oceans also get warmer and hot water expands and takes up more space. But how much do the experts expect the sea levels to rise during this century at the maximum?

Melting of the ice sheets

“We wanted to try to calculate an upper limit for the rise in sea level and the biggest question is the melting of the ice sheets and how quickly this will happen. The IPCC restricted their projektions to only using results based on models of each process that contributes to sea level. But the greatest uncertainty in assessing the evolution of sea levels is that ice sheet models have only a limited ability to capture the key driving forces in the dynamics of the ice sheets in relation to climatic impact,” Aslak Grinsted, Associate Professor at the Centre for Ice and Climate at the Niels Bohr Institute at the University of Copenhagen.

Aslak Grinsted has therefore, in collaboration with researchers from England and China, worked out new calculations. The researchers have combined the IPCC numbers with published data about the expectations within the ice-sheet expert community for the evolution, including the risk for the collapse of parts of Antarctica and how quickly such a collapse would take place.

“We have created a picture of the propable limits for how much global sea levels will rise in this century. Our calculations show that the seas will likely rise around 80 cm. An increase of more than 180 cm has a likelihood of less than 5 percent. We find that a rise in sea levels of more than 2 meters is improbable,” Aslak Grinsted, but points that the results only concern this century and the sea levels will continue to rise for centuries to come.


Story Source:

The above story is based on materials provided by University of Copenhagen. Note: Materials may be edited for content and length.


Journal Reference:

  1. S Jevrejeva, A Grinsted, J C Moore. Upper limit for sea level projections by 2100. Environmental Research Letters, 2014; 9 (10): 104008 DOI: 10.1088/1748-9326/9/10/104008

Crocodiles are sophisticated hunters: Work as a team to hunt their prey

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[dropcap]R[/dropcap]ecent studies have found that crocodiles and their relatives are highly intelligent animals capable of sophisticated behavior such as advanced parental care, complex communication and use of tools for hunting.

New University of Tennessee, Knoxville, research published in the journal Ethology Ecology and Evolution shows just how sophisticated their hunting techniques can be.

Vladimir Dinets, a research assistant professor in UT’s Department of Psychology, has found that crocodiles work as a team to hunt their prey. His research tapped into the power of social media to document such behavior.

Studying predatory behavior by crocodiles and their relatives such as alligators and caimans in the wild is notoriously difficult because they are ambush hunters, have slow metabolisms and eat much less frequently than warm-blooded animals. In addition, they are mostly nocturnal and often hunt in murky, overgrown waters of remote tropical rivers and swamps. Accidental observations of their hunting behavior are often made by non-specialists and remain unpublished or appear in obscure journals.

[dropcap]T[/dropcap]o overcome these difficulties, Dinets used Facebook and other social media sites to solicit eyewitness accounts from amateur naturalists, crocodile researchers and nonscientists working with crocodiles. He also looked through diaries of scientists and conducted more than 3,000 hours of observations himself.

All that work produced just a handful of observations, some dating back to the 19th century. Still, the observations had something in common — coordination and collaboration among the crocodiles in hunting their prey.

“Despite having been made independently by different people on different continents, these records showed striking similarities. This suggests that the observed phenomena are real, rather than just tall tales or misinterpretation,” said Dinets.

Crocodiles and alligators were observed conducting highly organized game drives. For example, crocodiles would swim in a circle around a shoal of fish, gradually making the circle tighter until the fish were forced into a tight “bait ball.” Then the crocodiles would take turns cutting across the center of the circle, snatching the fish.

Sometimes animals of different size would take up different roles. Larger alligators would drive a fish from the deeper part of a lake into the shallows, where smaller, more agile alligators would block its escape. In one case, a huge saltwater crocodile scared a pig into running off a trail and into a lagoon where two smaller crocodiles were waiting in ambush — the circumstances suggested that the three crocodiles had anticipated each other’s positions and actions without being able to see each other.

“All these observations indicate that crocodilians might belong to a very select club of hunters — just 20 or so species of animals, including humans — capable of coordinating their actions in sophisticated ways and assuming different roles according to each individual’s abilities. In fact, they might be second only to humans in their hunting prowess,” said Dinets.

Dinets said more observations are needed to better understand what exactly the animals are capable of. “And these observations don’t come easily,” he said.

Previous research by Dinets discovered that crocodiles are able to climb trees and use lures such as sticks to hunt prey. More of his crocodile research can be found in his book “Dragon Songs.”


Story Source:

The above story is based on materials provided by University of Tennessee. Note: Materials may be edited for content and length.


Journal Reference:

  1. Vladimir Dinets. Apparent coordination and collaboration in cooperatively hunting crocodilians. Ethology Ecology & Evolution, 2014; 1 DOI:10.1080/03949370.2014.915432

Fusion reactor concept could be cheaper than coal

The UW’s current fusion experiment, HIT-SI3. It is about one-tenth the size of the power-producing dynomak concept. Credit: Image courtesy of University of Washington
The UW’s current fusion experiment, HIT-SI3. It is about one-tenth the size of the power-producing dynomak concept.
Credit: Image courtesy of University of Washington

[dropcap]F[/dropcap]usion energy almost sounds too good to be true — zero greenhouse gas emissions, no long-lived radioactive waste, a nearly unlimited fuel supply.

Perhaps the biggest roadblock to adopting fusion energy is that the economics haven’t penciled out. Fusion power designs aren’t cheap enough to outperform systems that use fossil fuels such as coal and natural gas.

University of Washington engineers hope to change that. They have designed a concept for a fusion reactor that, when scaled up to the size of a large electrical power plant, would rival costs for a new coal-fired plant with similar electrical output.

The team published its reactor design and cost-analysis findings last spring and will present results Oct. 17 at the International Atomic Energy Agency’s Fusion Energy Conference in St. Petersburg, Russia.

“Right now, this design has the greatest potential of producing economical fusion power of any current concept,” said Thomas Jarboe, a UW professor of aeronautics and astronautics and an adjunct professor in physics.

The UW’s reactor, called the dynomak, started as a class project taught by Jarboe two years ago. After the class ended, Jarboe and doctoral student Derek Sutherland — who previously worked on a reactor design at the Massachusetts Institute of Technology — continued to develop and refine the concept.

The design builds on existing technology and creates a magnetic field within a closed space to hold plasma in place long enough for fusion to occur, allowing the hot plasma to react and burn. The reactor itself would be largely self-sustaining, meaning it would continuously heat the plasma to maintain thermonuclear conditions. Heat generated from the reactor would heat up a coolant that is used to spin a turbine and generate electricity, similar to how a typical power reactor works.

“This is a much more elegant solution because the medium in which you generate fusion is the medium in which you’re also driving all the current required to confine it,” Sutherland said.

There are several ways to create a magnetic field, which is crucial to keeping a fusion reactor going. The UW’s design is known as a spheromak, meaning it generates the majority of magnetic fields by driving electrical currents into the plasma itself. This reduces the amount of required materials and actually allows researchers to shrink the overall size of the reactor.

Other designs, such as the experimental fusion reactor project that’s currently being built in France — called Iter — have to be much larger than the UW’s because they rely on superconducting coils that circle around the outside of the device to provide a similar magnetic field. When compared with the fusion reactor concept in France, the UW’s is much less expensive — roughly one-tenth the cost of Iter — while producing five times the amount of energy.

The UW researchers factored the cost of building a fusion reactor power plant using their design and compared that with building a coal power plant. They used a metric called “overnight capital costs,” which includes all costs, particularly startup infrastructure fees. A fusion power plant producing 1 gigawatt (1 billion watts) of power would cost $2.7 billion, while a coal plant of the same output would cost $2.8 billion, according to their analysis.

“If we do invest in this type of fusion, we could be rewarded because the commercial reactor unit already looks economical,” Sutherland said. “It’s very exciting.”

Right now, the UW’s concept is about one-tenth the size and power output of a final product, which is still years away. The researchers have successfully tested the prototype’s ability to sustain a plasma efficiently, and as they further develop and expand the size of the device they can ramp up to higher-temperature plasma and get significant fusion power output.

The team has filed patents on the reactor concept with the UW’s Center for Commercialization and plans to continue developing and scaling up its prototypes.

Other members of the UW design team include Kyle Morgan of physics; Eric Lavine, Michal Hughes, George Marklin, Chris Hansen, Brian Victor, Michael Pfaff, and Aaron Hossack of aeronautics and astronautics; Brian Nelson of electrical engineering; and, Yu Kamikawa and Phillip Andrist formerly of the UW.

The research was funded by the U.S. Department of Energy.


Story Source:

The above story is based on materials provided by University of Washington. The original article was written by Michelle Ma. Note: Materials may be edited for content and length.


Journal Reference:

  1. D.A. Sutherland, T.R. Jarboe, K.D. Morgan, M. Pfaff, E.S. Lavine, Y. Kamikawa, M. Hughes, P. Andrist, G. Marklin, B.A. Nelson. The dynomak: An advanced spheromak reactor concept with imposed-dynamo current drive and next-generation nuclear power technologies. Fusion Engineering and Design, 2014; 89 (4): 412 DOI: 10.1016/j.fusengdes.2014.03.072

Smallest possible diamonds form ultra-thin nanothreads

For the first time, scientists have discovered how to produce ultra-thin 'diamond nanothreads' that promise extraordinary properties, including strength and stiffness greater than that of today's strongest nanotubes and polymers. The threads have a structure that has never been seen before. A paper describing this discovery by a research team led by John V. Badding, a professor of chemistry at Penn State University, will be published in the 21 Sept. 2014 issue of the journal Nature Materials. The core of the nanothreads that Badding's team made is a long, thin strand of carbon atoms arranged just like the fundamental unit of a diamond's structure -- zig-zag 'cyclohexane' rings of six carbon atoms bound together, in which each carbon is surrounded by others in the strong triangular-pyramid shape of a tetrahedron. Credit: Penn State University
For the first time, scientists have discovered how to produce ultra-thin ‘diamond nanothreads’ that promise extraordinary properties, including strength and stiffness greater than that of today’s strongest nanotubes and polymers. The threads have a structure that has never been seen before. A paper describing this discovery by a research team led by John V. Badding, a professor of chemistry at Penn State University, will be published in the 21 Sept. 2014 issue of the journal Nature Materials. The core of the nanothreads that Badding’s team made is a long, thin strand of carbon atoms arranged just like the fundamental unit of a diamond’s structure — zig-zag ‘cyclohexane’ rings of six carbon atoms bound together, in which each carbon is surrounded by others in the strong triangular-pyramid shape of a tetrahedron.
Credit: Penn State University

[dropcap]F[/dropcap]or the first time, scientists have discovered how to produce ultra-thin “diamond nanothreads” that promise extraordinary properties, including strength and stiffness greater than that of today’s strongest nanotubes and polymers. A paper describing this discovery by a research team led by John V. Badding, a professor of chemistry at Penn State University, will be published in the 21 September 2014 issue of the journalNature Materials.

“From a fundamental-science point of view, our discovery is intriguing because the threads we formed have a structure that has never been seen before,” Badding said. The core of the nanothreads that Badding’s team made is a long, thin strand of carbon atoms arranged just like the fundamental unit of a diamond’s structure — zig-zag “cyclohexane” rings of six carbon atoms bound together, in which each carbon is surrounded by others in the strong triangular-pyramid shape of a tetrahedron. “It is as if an incredible jeweler has strung together the smallest possible diamonds into a long miniature necklace,” Badding said. “Because this thread is diamond at heart, we expect that it will prove to be extraordinarily stiff, extraordinarily strong, and extraordinarily useful.”

The team’s discovery comes after nearly a century of failed attempts by other labs to compress separate carbon-containing molecules like liquid benzene into an ordered, diamondlike nanomaterial. “We used the large high-pressure Paris-Edinburgh device at Oak Ridge National Laboratory to compress a 6-millimeter-wide amount of benzene — a gigantic amount compared with previous experiments,” said Malcolm Guthrie of the Carnegie Institution for Science, a coauthor of the research paper. “We discovered that slowly releasing the pressure after sufficient compression at normal room temperature gave the carbon atoms the time they needed to react with each other and to link up in a highly ordered chain of single-file carbon tetrahedrons, forming these diamond-core nanothreads.”

Badding’s team is the first to coax molecules containing carbon atoms to form the strong tetrahedron shape, then link each tetrahedron end to end to form a long, thin nanothread. He describes the thread’s width as phenomenally small, only a few atoms across, hundreds of thousands of times smaller than an optical fiber, enormously thinner that an average human hair. “Theory by our co-author Vin Crespi suggests that this is potentially the strongest, stiffest material possible, while also being light in weight,” he said.

The molecule they compressed is benzene — a flat ring containing six carbon atoms and six hydrogen atoms. The resulting diamond-core nanothread is surrounded by a halo of hydrogen atoms. During the compression process, the scientists report, the flat benzene molecules stack together, bend, and break apart. Then, as the researchers slowly release the pressure, the atoms reconnect in an entirely different yet very orderly way. The result is a structure that has carbon in the tetrahedral configuration of diamond with hydrogens hanging out to the side and each tetrahedron bonded with another to form a long, thin, nanothread.

“It really is surprising that this kind of organization happens,” Badding said. “That the atoms of the benzene molecules link themselves together at room temperature to make a thread is shocking to chemists and physicists. Considering earlier experiments, we think that, when the benzene molecule breaks under very high pressure, its atoms want to grab onto something else but they can’t move around because the pressure removes all the space between them. This benzene then becomes highly reactive so that, when we release the pressure very slowly, an orderly polymerization reaction happens that forms the diamond-core nanothread.”

The scientists confirmed the structure of their diamond nanothreads with a number of techniques at Penn State, Oak Ridge, Arizona State University, and the Carnegie Institution for Science, including X-ray diffraction, neutron diffraction, Raman spectroscopy, first-principle calculations, transmission electron microscopy, and solid-state nuclear magnetic resonance (NMR). Parts of these first diamond nanothreads appear to be somewhat less than perfect, so improving their structure is a continuing goal of Badding’s research program. He also wants to discover how to make more of them. “The high pressures that we used to make the first diamond nanothread material limit our production capacity to only a couple of cubic millimeters at a time, so we are not yet making enough of it to be useful on an industrial scale,” Badding said. “One of our science goals is to remove that limitation by figuring out the chemistry necessary to make these diamond nanothreads under more practical conditions.”

The nanothread also may be the first member of a new class of diamond-like nanomaterials based on a strong tetrahedral core. “Our discovery that we can use the natural alignment of the benzene molecules to guide the formation of this new diamond nanothread material is really interesting because it opens the possibility of making many other kinds of molecules based on carbon and hydrogen,” Badding said. “You can attach all kinds of other atoms around a core of carbon and hydrogen. The dream is to be able to add other atoms that would be incorporated into the resulting nanothread. By pressurizing whatever liquid we design, we may be able to make an enormous number of different materials.”

Potential applications that most interest Badding are those that would be vastly improved by having exceedingly strong, stiff, and light materials — especially those that could help to protect the atmosphere, including lighter, more fuel-efficient, and therefore less-polluting vehicles. “One of our wildest dreams for the nanomaterials we are developing is that they could be used to make the super-strong, lightweight cables that would make possible the construction of a “space elevator,” which so far has existed only as a science-fiction idea,” Badding said.

In addition to Badding at Penn State and Guthrie at the Carnegie Institution, other members of the research team include George D. Cody at the Carnegie Institution, Stephen K. Davidowski, at Arizona State, and Thomas C. Fitzgibbons, En-shi Xu, Vincent H. Crespi, and Nasim Alem at Penn State. Penn State affiliations include the Department of Chemistry, the Materials Research Institute, the Department of Physics, and the Department of Materials Science and Engineering. This research received financial support as part of the Energy Frontier Research in Extreme Environments (EFree) Center, and Energy Frontier Research Center funded by the U.S. Department of Energy (Office of Science award #DE-SC0001057).


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The above story is based on materials provided by Penn State. The original article was written by Barbara K. Kennedy. Note: Materials may be edited for content and length.