Last Universal Common Ancestor More Complex Than Previously Thought
|3:42:30 AM, Sunday, October 23, 2011|
"Scientists call it LUCA, the Last Universal Common Ancestor, but they don't know much about this great-grandparent of all living things. Many believe LUCA was little more than a crude assemblage of molecular parts, a chemical soup out of which evolution gradually constructed more complex forms. Some scientists still debate whether it was even a cell.
New evidence suggests that LUCA was a sophisticated organism after all, with a complex structure recognizable as a cell, researchers report. Their study appears in the journal Biology Direct.
The study builds on several years of research into a once-overlooked feature of microbial cells, a region with a high concentration of polyphosphate, a type of energy currency in cells. Researchers report that this polyphosphate storage site actually represents the first known universal organelle, a structure once thought to be absent from bacteria and their distantly related microbial cousins, the archaea. This organelle, the evidence indicates, is present in the three domains of life: bacteria, archaea and eukaryotes (plants, animals, fungi, algae and everything else).
The existence of an organelle in bacteria goes against the traditional definition of these organisms, said University of Illinois crop sciences professor Manfredo Seufferheld, who led the study.
"It was a dogma of microbiology that organelles weren't present in bacteria," he said. But in 2003 in a paper in the Journal of Biological Chemistry, Seufferheld and colleagues showed that the polyphosphate storage structure in bacteria (they analyzed an agrobacterium) was physically, chemically and functionally the same as an organelle called an acidocalcisome (uh-SID-oh-KAL-sih-zohm) found in many single-celled eukaryotes.
Their findings, the authors wrote, "suggest that acidocalcisomes arose before the prokaryotic (bacterial) and eukaryotic lineages diverged." The new study suggests that the origins of the organelle are even more ancient.
The study tracks the evolutionary history of a protein enzyme (called a vacuolar proton pyrophosphatase, or V-H+PPase) that is common in the acidocalcisomes of eukaryotic and bacterial cells. (Archaea also contain the enzyme and a structure with the same physical and chemical properties as an acidocalcisome, the researchers report.)
By comparing the sequences of the V-H+PPase genes from hundreds of organisms representing the three domains of life, the team constructed a "family tree" that showed how different versions of the enzyme in different organisms were related. That tree was similar in broad detail to the universal tree of life created from an analysis of hundreds of genes. This indicates, the researchers said, that the V-H+PPase enzyme and the acidocalcisome it serves are very ancient, dating back to the LUCA, before the three main branches of the tree of life appeared.
"There are many possible scenarios that could explain this, but the best, the most parsimonious, the most likely would be that you had already the enzyme even before diversification started on Earth," said study co-author Gustavo Caetano-Anollés, a professor of crop sciences and an affiliate of the Institute for Genomic Biology at Illinois. "The protein was there to begin with and was then inherited into all emerging lineages."
"This is the only organelle to our knowledge now that is common to eukaryotes, that is common to bacteria and that is most likely common to archaea," Seufferheld said. "It is the only one that is universal."
The study lends support to a hypothesis that LUCA may have been more complex even than the simplest organisms alive today, said James Whitfield, a professor of entomology at Illinois and a co-author on the study..."
Animal Transplants Coming 'Soon'
|3:37:01 AM, Sunday, October 23, 2011|
"Are pigs about to migrate from the dinner table to the operating table?
Using animals as a source of organs for transplantation into humans was once one of medicine's next big things - a solution to transplant waiting lists.
However, there have been problems with rejection - and recently stem cells have been grabbing the spotlight.
But some researchers are now saying that transplants from animals "could soon become a reality", but not necessarily as originally expected.
There is still a pressing need for organs. In the UK there are 8,000 people on the waiting list - three die every day.
Several technologies are trying to meet the demand. In August, a patient from London was the first in the UK to have his heart replaced with a mechanical one while stem cells have been used for simple structures such as the windpipe.
However, using stem cells to build more complicated organs such as a heart is a long way off and mechanical body parts are used in the short term before an actual transplant.
Using animals as a source - known as "xenotransplantation" - is another potential solution.
Pigs have been used as a source of heart valves, which control the flow of blood around the heart. Here the pig cells are chemically stripped away and when the remaining structure is transplanted, human cells grow around it.
Stripping away the living material would not work for most transplants - nobody would want the heart that did not beat.
However, that living material has a big problem, namely rejection. The human immune system attacks the pig tissue, which it recognises as foreign.
Dr David Cooper from the University of Pittsburgh Medical Centre is one of a group of researchers arguing in the Lancet that the problems with organ rejection are being overcome.
Some pigs - GTKO pigs - have been genetically modified. They no longer produce a pig protein, galactosyltransferase, which the immune system would have attacked.
The authors say that this kind of rejection is "not the main cause of graft failure", however, "other issues have become more prominent"..."
Hawaii Astronomer Captures Image of Forming Planet
|8:27:36 PM, Thursday, October 20, 2011|
“Astronomers have captured the first direct image of a planet being born.
Adam Kraus, of the University of Hawaii's Institute for Astronomy, said the planet is being formed out of dust and gas circling a 2-milion-year-old star about 450 light years from Earth.
The planet itself, based on scientific models of how planets form, is estimated to have started taking shape about 50,000 to 100,000 years ago.
Called LkCa 15 b, it's the youngest planet ever observed. The previous record holder was about five times older.
Kraus and his colleague, Michael Ireland from Macquarie University and the Australian Astronomical Observatory, used Keck telescopes on Mauna Kea to find the planet.
"We're catching this object at the perfect time. We see this young star, it has a disc around it that planets are probably forming out of and we see something right in the middle of a gap in the disc," Kraus said in a telephone interview.
Kraus presented the discovery Wednesday at NASA's Goddard Space Flight Center in Maryland. Kraus and Ireland's research paper on the discovery is due to appear in The Astrophysical Journal.
Observing planets while they're forming can help scientists answer questions like whether planets form early in the life of a star or later, and whether they form relatively close to stars or farther away.
Planets can change orbits after forming, so it's difficult to answer such questions by studying older planets.
"These very basic questions of when and where are best answered when you can actually see the planet forming, as the process is happening right now," Kraus said.
Other planets may also be forming around the same star. Kraus said he'll continue to observe the star and hopefully will see other planets if there are in fact more.
Scientists hadn't been able to see such young planets before because the bright light of the stars they're orbiting outshines them.
Kraus and Ireland used two techniques to overcome this obstacle.
One method, which is also used by other astronomers, was to change the shape of their mirror to remove light distortions created by the Earth's atmosphere.
The other, unique method they used was to put masks over most of the telescope mirror. The combination of these two techniques allowed the astronomers to obtain high-resolution images that let them see the faint planet next to the bright star.
The astronomers found the planet while surveying 150 young dusty stars. This led to a more concentrated study of a dozen stars.
The star LkCa 15 — the planet is named after its star — was the team's second target. They immediately knew they were seeing something new, so they gathered more data on the star a year later.”
Qaddafi Is Killed as Libyan Forces Take Surt
|3:41:01 PM, Thursday, October 20, 2011|
"TRIPOLI, Libya — Col. Muammar el-Qaddafi, the former Libyan strongman who fled into hiding after an armed uprising toppled his regime two months ago, met a violent death Thursday in the hands of rebel fighters who stormed his final stronghold in his Mediterranean hometown Surt.
Al Jazeera television showed gruesome footage of what appeared to be Colonel Qaddafi, alive but bloody, being dragged around by armed men in Surt. The television also broadcast a separate clip of his half-naked body, with lifeless open eyes and an apparent gunshot wound to the side of the head, as jubilant fighters fired automatic weapons in the air.
Conflicting accounts quickly emerged about whether Colonel Qaddafi was executed by his captors, died from gunshot wounds sustained in a firefight, was mortally wounded in a NATO bomb blast or bled to death in an ambulance. But the images broadcast by Al Jazeera punctuated an emphatic and violent ending to his four decades as a ruthless and bombastic autocrat who had basked in his reputation as the self-styled king of kings of Africa.
“We have been waiting for this moment for a long time. Muammar Qaddafi has been killed,” Mahmoud Jibril, the prime minister of the Transitional National Council, the interim government, told a news conference in Tripoli. Mahmoud Shammam, the council’s chief spokesman, called it “the day of real liberation. We were serious about giving him a fair trial. It seems God has some other wish."
Libyan television also reported that one of Colonel Qaddafi’s feared fugitive sons, Muatassim, was killed in Surt, showing what it said was his lifeless bloodied body on a hospital gurney. There were also unconfirmed accounts that another feared son, Seif al-Islam, had been captured and possibly wounded.
In Washington, President Obama said in a televised statement that the death of Colonel Qaddafi signaled the start of a new chapter for Libya. “We can definitely say that the Qaddafi regime has come to an end,” he said. “The dark shadow of tyranny has been lifted and with this enormous promise the Libyan people now have a great responsibility to build an inclusive and tolerant and democratic Libya that stands as the ultimate rebuke to Qaddafi’s dictatorship.”
Libyans rejoiced as news of his death spread. Car horns blared and residents poured into the streets in giddy disbelief in Tripoli and in the eastern city of Benghazi, where the rebellion against Colonel Qaddafi began in February and escalated into the most violent of the Arab Spring uprisings.
“I can’t believe it’s over,” said Tahir Busrewil, a 26 year-old tourist industry worker in Tripoli who was imprisoned and tortured earlier this year, and had spent the past few weeks working with a militia to detain pro-Qaddafi loyalists. “Oh the relief! I never felt that happy about somebody being dead.” Walid Fakany, an anti-Qaddafi fighter from the Western mountain town of Rujban, who joined in the celebrations in Tripoli, said: “We can breathe, we can finally rest. Then we can move forward.”
Fighters from Misurata, the port city that suffered enormously at the hands of Colonel Qaddafi’s forces during the uprising, were in possession of Colonel Qaddafi’s body and took it to their hometown, where it was kept in a private house but moved a few hours later to an undisclosed location because hundreds of people had converged to see it, Misurata residents said.
Holly Picket, a freelance photojournalist working in Surt, reported in a twitter feed that she had seen Colonel Qaddafi’s body in an ambulance headed for Misurata, along with 10 fighters inside with him. It was unclear from her posting whether he was dead. “From the side door, I could see a bare chest with bullet wound and a bloody hand. He was wearing gold-colored pants,” she tweeted.
Within an hour of the news of Colonel Qaddafi’s death, the Arab twittersphere lit up with gleeful comments, many of them hinting at a similar fate awaiting other Arab dictators — most notably President Ali Abdullah Saleh of Yemen and President Bashar al-Assad of Syria. One of them read: “Ben Ali escaped, Mubarak is in jail, Qaddafi was killed. Which fate do you prefer, Ali Abdullah Saleh? You can consult with Bashar.” Another was more direct: “Bashar al-Assad, how do you feel today?” ..."
Fiery Volcano Offers Geologic Glimpse Into Land That Time Forgot
|4:06:53 AM, Thursday, October 20, 2011|
"The first scientists to witness exploding rock and molten lava from a deep sea volcano, seen during a 2009 expedition, report that the eruption was near a tear in Earth's crust that is mimicking the birth of a subduction zone.
Scientists on the expedition collected boninite, a rare, chemically distinct lava that accompanies the formation of Earth's subduction zones.
Nobody has ever collected fresh boninite and scientists never had the opportunity to monitor its eruption before, said Joseph Resing, University of Washington oceanographer and lead author of an online article on the findings in Nature Geoscience. Earth's current subduction zones are continually evolving but most formed 5 million to 200 million years ago. Scientists have only been able to study boninite collected from long-dead, relic volcanos millions of years old.
Resing was chief scientist on the expedition, funded by the National Oceanic and Atmospheric Administration and the National Science Foundation, that pinpointed the location of the West Mata volcano, erupting 4,000 feet (1,200 meters) below the surface in the Southwest Pacific Ocean.
"Everything about the eruption itself -- how fast, how intense, the ratio of lava to explosive fragments, the amount and composition of gas released -- is new to us," said co-author Kenneth Rubin, University of Hawaii geologist. "Plus, having a young, fresh occurrence of this very rare rock type to study gives us the opportunity to examine subtle chemical and mineralogical variations in a pristine specimen."
At subduction zones the oceanic crust on one tectonic plate slides beneath another, producing abundant volcanism and contributing heat, gases and mineral-laden fluids to ocean waters. Scientists have long studied the impact of subduction zones on geological and geochemical cycles. To puzzle out how subduction zones form and evolve they study inactive contemporary marine volcanos that do not produce boninite and they collect and study boninite lavas collected on land and examine cores collected from the deep sea.
"West Mata lies above the subducting Pacific plate and is part of the rapidly expanding Lau Basin, which is bounded by Samoa, Tonga and Fiji," Resing said. "The large bend at the northern end of the Tonga trench produces a tear in the Pacific plate and creates unusual lavas that usually only form at very young subduction zones."
Conditions are right for boninite to form, there's lots of seawater released from subducting rock that mixes into relatively shallow mantle that has previously melted, causing the mantle to remelt at high temperatures. Boninite lavas are believed to be among the hottest from volcanos that erupt on Earth..."
Detroit Police Impound Booty Lounge Strip Club on Wheels
|3:36:12 AM, Thursday, October 20, 2011|
"Tailgating is an important part of going to see a sports event in person, and in the city of Detroit, that pastime also includes something called the Booty Lounge. The Booty Lounge is a low-rent strip-club on wheels, and it has been a somewhat shady part of the game-day experience in Detroit since 2005.
Owners of the mobile strip club were likely hoping for a big payday thanks to a Lions appearance on the NFL's Monday Night Football, but instead, the bus was impounded by Detroit Police. Detroit's NBC affiliate reports that the bus was towed way because it was parked illegally, the driver didn't have a commercial license and the vehicle wasn't inspected by the Michigan Department of Transportation. The fuzz reportedly weren't targeting the rolling tribute, but the bus recently came under fire after a local TV station uncovered the goings-on inside the bus.
The Booty Lounge will reportedly be cleared to exit the impound once it provides proof of inspection, but we're getting the feeling that this tailgater is going to be sitting out a quite few more games."
Dark Matter Mystery Deepens
|1:06:31 AM, Thursday, October 20, 2011|
"Like all galaxies, our Milky Way is home to a strange substance called dark matter. Dark matter is invisible, betraying its presence only through its gravitational pull. Without dark matter holding them together, our galaxy's speedy stars would fly off in all directions. The nature of dark matter is a mystery -- a mystery that a new study has only deepened.
"After completing this study, we know less about dark matter than we did before," said lead author Matt Walker, a Hubble Fellow at the Harvard-Smithsonian Center for Astrophysics.
The standard cosmological model describes a universe dominated by dark energy and dark matter. Most astronomers assume that dark matter consists of "cold" (i.e. slow-moving) exotic particles that clump together gravitationally. Over time these dark matter clumps grow and attract normal matter, forming the galaxies we see today.
Cosmologists use powerful computers to simulate this process. Their simulations show that dark matter should be densely packed in the centers of galaxies. Instead, new measurements of two dwarf galaxies show that they contain a smooth distribution of dark matter. This suggests that the standard cosmological model may be wrong.
"Our measurements contradict a basic prediction about the structure of cold dark matter in dwarf galaxies. Unless or until theorists can modify that prediction, cold dark matter is inconsistent with our observational data," Walker stated.Dwarf galaxies are composed of up to 99 percent dark matter and only one percent normal matter like stars. This disparity makes dwarf galaxies ideal targets for astronomers seeking to understand dark matter.
Walker and his co-author Jorge Peñarrubia (University of Cambridge, UK) analyzed the dark matter distribution in two Milky Way neighbors: the Fornax and Sculptor dwarf galaxies. These galaxies hold one million to 10 million stars, compared to about 400 billion in our galaxy. The team measured the locations, speeds and basic chemical compositions of 1500 to 2500 stars..."
U.S. Drug Policy Would Be Imposed Globally By New House Bill
|12:21:06 AM, Thursday, October 20, 2011|
"The House Judiciary Committee passed a bill yesterday that would make it a federal crime for U.S. residents to discuss or plan activities on foreign soil that, if carried out in the U.S., would violate the Controlled Substances Act (CSA) -- even if the planned activities are legal in the countries where they're carried out. H.R. 313, the "Drug Trafficking Safe Harbor Elimination Act of 2011," is sponsored by Judiciary Committee Chairman Rep. Lamar Smith (R-Texas), and allows prosecutors to bring conspiracy charges against anyone who discusses, plans or advises someone else to engage in any activity that violates the CSA, the massive federal law that prohibits drugs like marijuana and strictly regulates prescription medication.
"Under this bill, if a young couple plans a wedding in Amsterdam, and as part of the wedding, they plan to buy the bridal party some marijuana, they would be subject to prosecution," said Bill Piper, director of national affairs for the Drug Policy Alliance, which advocates for reforming the country's drug laws. "The strange thing is that the purchase of and smoking the marijuana while you're there wouldn't be illegal. But this law would make planning the wedding from the U.S. a federal crime."
The law could also potentially affect academics and medical professionals. For example, a U.S. doctor who works with overseas doctors or government officials on needle exchange programs could be subject to criminal prosecution. A U.S. resident who advises someone in another country on how to grow marijuana or how to run a medical marijuana dispensary would also be in violation of the new law, even if medical marijuana is legal in the country where the recipient of the advice resides. If interpreted broadly enough, a prosecutor could possibly even charge doctors, academics and policymakers from contributing their expertise to additional experiments like the drug decriminalization project Portugal, which has successfully reduced drug crime, addiction and overdose deaths.
The Controlled Substances Act also regulates the distribution of prescription drugs, so something as simple as emailing a friend vacationing in Tijuana some suggestions on where to buy prescription medication over the counter could subject a U.S. resident to criminal prosecution. "It could even be something like advising them where to buy cold medicine overseas that they'd have to show I.D. to get here in the U.S.," Piper says.
Civil libertarian attorney and author Harvey Silverglate says the bill raises several concerns. "Just when you think you can't get any more cynical, a bill like this comes along. I mean, it just sounds like an abomination. First, there's no intuitive reason for an American to think that planning an activity that's perfectly legal in another country would have any effect on America," Silverglate says. "So we're getting further away from the common law tradition that laws should be intuitive, and should include a mens rea component. Second, this is just an act of shameless cultural and legal imperialism. It's just outrageous."
Conspiracy laws in general are problematic when applied to the drug war. They give prosecutors extraordinary discretion to charge minor players, such as girlfriends or young siblings, with the crimes committed by major drug distributors. They're also easier convictions to win, and can allow prosecutors to navigate around restrictions like statutes of limitations, so long as the old offense can be loosely linked to a newer one. The Smith bill would expand those powers. Under the Amsterdam wedding scenario, anyone who participated in the planning of the wedding with knowledge of the planned pot purchase would be guilty of conspiracy, even if their particular role was limited to buying flowers or booking the hotel.
The law is a reaction to a 2007 case in which the 11th Circuit U.S. Court of Appeals threw out the convictions of two men who planned the transfer of cocaine from a Colombian drug cartel to a Saudi prince for distribution in Europe. Though the men planned the transaction from Miami, the court found that because the cocaine never reached the U.S. and was never intended to reach the U.S., the men hadn't committed any crime against the United States..."
NASA's Spitzer Detects Comet Storm in Nearby Solar System
|12:13:22 AM, Thursday, October 20, 2011|
"NASA's Spitzer Space Telescope has detected signs of icy bodies raining down in an alien solar system. The downpour resembles our own solar system several billion years ago during a period known as the "Late Heavy Bombardment," which may have brought water and other life-forming ingredients to Earth.
During this epoch, comets and other frosty objects that were flung from the outer solar system pummeled the inner planets. The barrage scarred our moon and produced large amounts of dust.
Now Spitzer has spotted a band of dust around a nearby bright star in the northern sky called Eta Corvi that strongly matches the contents of an obliterated giant comet. This dust is located close enough to Eta Corvi that Earth-like worlds could exist, suggesting a collision took place between a planet and one or more comets. The Eta Corvi system is approximately one billion years old, which researchers think is about the right age for such a hailstorm.
"We believe we have direct evidence for an ongoing Late Heavy Bombardment in the nearby star system Eta Corvi, occurring about the same time as in our solar system," said Carey Lisse, senior research scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md., and lead author of a paper detailing the findings. The findings will be published in the Astrophysical Journal. Lisse presented the results at the Signposts of Planets meeting at NASA's Goddard Space Flight Center in Greenbelt, Md., on Oct. 19.
Astronomers used Spitzer's infrared detectors to analyze the light coming from the dust around Eta Corvi. Certain chemical fingerprints were observed, including water ice, organics and rock, which indicate a giant comet source.
The light signature emitted by the dust around Eta Corvi also resembles the Almahata Sitta meteorite, which fell to Earth in fragments across Sudan in 2008. The similarities between the meteorite and the object obliterated in Eta Corvi imply a common birthplace in their respective solar systems.
A second, more massive ring of colder dust located at the far edge of the Eta Corvi system seems like the proper environment for a reservoir of cometary bodies. This bright ring, discovered in 2005, looms at about 150 times the distance from Eta Corvi as Earth is from the sun. Our solar system has a similar region, known as the Kuiper Belt, where icy and rocky leftovers from planet formation linger. The new Spitzer data suggest that the Almahata Sitta meteorite may have originated in our own Kuiper Belt..."
Prehistoric Speedway: Super-Sized Muscle Made Twin-Horned Dinosaur a Speedster
|2:37:29 AM, Wednesday, October 19, 2011|
"A meat-eating dinosaur that terrorized its plant-eating neighbours in South America was a lot deadlier than first thought, a University of Alberta researcher has found.
Carnotaurus was a seven-metre-long predator with a huge tail muscle that U of A paleontology graduate student Scott Persons says made it one of the fastest running hunters of its time.
A close examination of the tail bones of Carnotaurus showed its caudofemoralis muscle had a tendon that attached to its upper leg bones. Flexing this muscle pulled the legs backwards and gave Carnotaurus more power and speed in every step.
In earlier research, Persons found a similar tail-muscle and leg-power combination in the iconic predator Tyrannosaurus rex. Up until Persons published that paper, many dinosaur researchers thought T. rex's huge tail might have simply served as a teeter-totter-like counterweight to its huge, heavy head.
Persons' examination of the tail of Carnotaurus showed that along its length were pairs of tall rib-like bones that interlocked with the next pair in line. Using 3-D computer models, Persons recreated the tail muscles of Carnotaurus. He found that the unusual tail ribs supported a huge caudofemoralis muscle. The interlocked bone structure along the dinosaur's tail did present one drawback: the tail was rigid, making it difficult for the hunter to make quick, fluid turns. Persons says that what Carnotaurus gave up in maneuverability, it made up for in straight ahead speed. For its size, Carnotaurus had the largest caudofemoralis muscle of any known animal, living or extinct.
Persons published these findings in PLoS ONE on Oct.14, with supervisor Philip Currie, a paleontology professor at the U of A."
Frozen Puck Hovers Over Track Using “Quantum Levitation”
|12:18:44 AM, Wednesday, October 19, 2011|
"Researchers at the school of physics and astronomy at Tel Aviv University have created a track around which a semiconductor can float, thanks to the phenomenon of “quantum levitation“.
This levitation effect is explained by the Meissner effect, which describes how, when a material makes the transition from its normal to its superconducting state, it actively excludes magnetic fields from its interior, leaving only a thin layer on its surface.
When a material is in its superconducting state — which involves very low temperatures — it is strongly diamagnetic. This means that when a magnetic field is externally applied, it will create an equally opposing magnetic field, locking it in place.
A material called yttrium barium copper oxide can be turned into a superconductor by exposure to liquid nitrogen — which makes it one of the highest-temperature superconductors.
In the video it appears that a puck of yttrium barium copper oxide cooled by liquid nitrogen is repelling the magnets embedded on the handheld device. It also shows that the angle of the magnet can be locked in a magnetic field. Later in the video the puck can be seen to zoom round a circular track of magnets, in the same way that Maglev high-speed trains do."
Frustration Inspires New Form of Graphene
|1:45:45 AM, Monday, October 17, 2011|
"They're the building block of graphite – ultra-thin sheets of carbon, just one atom thick, whose discovery was lauded in 2010 with a Nobel Prize in Physics.
The seemingly simple material is graphene, and many researchers believe it has great potential for many applications, from electronic devices to high-performance composite materials.
Graphene is extremely strong, an excellent conductor, and with no internal structure at all, it offers an abundance of surface area – much like a sheet of paper.
When it comes to producing and utilizing graphene on a large scale, however, researchers have come upon a major problem: the material's tendency to aggregate. Like paper, graphene sheets easily stack into piles, thus greatly reducing their surface area and making them unprocessable.
Researchers at Northwestern University have now developed a new form of graphene that does not stack. The new material – inspired by a trash can full of crumpled-up papers – is made by crumpling the graphene sheets into balls.
A paper describing the findings, "Compression and Aggregation-resistant Particles of Crumpled Soft Sheets," was published October 13 in the journal ACS Nano.
Graphene-based materials are very easily aggregated due to the strong interaction between the sheets, called "Van der Waals attraction." Therefore, common steps in materials processing, such as heating, solvent washing, compression, and mixing with other materials, can greatly affect how the sheets are stacked. When the paper-like sheets band together – picture a deck of cards – their surface area is lost; with just a fraction of its original surface area available, the material becomes less effective. Stacked graphene sheets also become rigid and lose their processability.
Some scientists have tried to physically keep the sheets apart by inserting non-carbon "spacers" between them, but that changes the chemical composition of the material. When graphene is crumpled into balls, however, its surface area remains available and the material remains pure.
"If you imagine a trash can filled with paper crumples, you really get the idea," says Jiaxing Huang, Morris E. Fine Junior Professor in Materials and Manufacturing, the lead researcher of the study. "The balls can stack up into a tight structure. You can crumple them as hard as you want, but their surface area won't be eliminated, unlike face-to-face stacking."
"Crumpled paper balls usually express an emotion of frustration, a quite common experience in research," Huang says, "However, here 'frustration' quite appropriately describes why these particles are resistant to aggregation – because their uneven surface frustrates or prevents tight face-to-face packing no matter how you process them."
To make crumpled graphene balls, Huang and his team created freely suspended water droplets containing graphene-based sheets, then used a carrier gas to blow the aerosol droplets through a furnace. As the water quickly evaporated, the thin sheets were compressed by capillary force into near-spherical particles..."
Russia Asked to Join ExoMars Project
|12:36:44 AM, Monday, October 17, 2011|
"Europe has formally invited Russia to participate in space missions to Mars in 2016 and 2018.
A "yes" from the Russian space agency (Roscosmos) may be the only way of saving the missions which are at risk of cancellation due to lack of funds.
The 2016 mission involves a satellite to study the Martian atmosphere, while a big robot rover to investigate the surface is scheduled for 2018.
Both are being planned with the US, which is also struggling financially.
If Russia can be persuaded to provide a rocket to launch the 2016 satellite, it should make both atmospheric and surface ventures financially feasible.
But the European and US space agencies (Esa and Nasa) know that for Roscosmos to be interested, it will want a meaningful degree of participation.
The in-kind return for Russia would be the opportunity to provide instrumentation and technology for the missions, and for its researchers to be included in the science teams.
"Everything is open for discussion," said Esa director of science, Alvaro Gimenez.
"There are possibilities for the Russians to contribute to the rover; there may also be possibilities for them to contribute to the payload on the orbiter," he told BBC News.
"Of course, in the case of 2016, we don't have much time available to get everything on board; and in the case of 2018, we don't have much room available because it is just a single Esa/Nasa rover.
"That's why we have to start the discussions now, to see what the Russians have available and what they can develop in a fast-track."
Esa's and Nasa's joint Mars programme (known in Europe as ExoMars) has looked increasingly unsteady in recent months.
The US let it be known during the summer that it could no longer afford to provide the rocket to launch the 2016 orbiter; and Europe, which still has not raised the full funds needed for ExoMars among its member states, has no money available to buy a rocket itself..."
Why Einstein Was Wrong About Being Wrong
|12:30:30 AM, Monday, October 17, 2011|
"If you want to get your mind around the research that won three astronomers the Nobel Prize in physics last week, it helps to think of the universe as a lump of dough - raisin-bread dough, to be precise - mixed, kneaded and ready to rise. Hold that thought.
Now consider Albert Einstein - not the wild-haired, elderly, absent-minded professor he became in his later years but a young, dashing scientist in his 30s. It's 1916, and he's just published his revolutionary general theory of relativity. It's not necessary to understand the theory (thank goodness). You just have to accept that it gave scientists the mathematical tools they needed to forge a better understanding of the cosmos than they'd ever had.
There was just one problem. Relativity told physicists that the universe was restless. It couldn't just sit there. It either had to be expanding or contracting. But astronomers looked, and as far as they could tell, it was doing neither. The lump of dough wasn't rising, and it wasn't shrinking.
The only way that was possible, Einstein realized, was if some mysterious force was propping up the universe, a sort of antigravity that pushed outward just hard enough to balance the gravity that was trying to pull it inward. Einstein hated this idea. An extra force meant he had to tinker with the equations of general relativity, but the equations seemed so perfect just as they were. Changing them in any way would tarnish their mathematical beauty.
Einstein did it anyway. The universe ought to behave according to the laws he had set out, but it simply wasn't cooperating. The "cosmological constant" - his name for the new antigravity force - became part of the theory.
Then, a decade or so later, the great astronomer Edwin Hubble went up to the Mount Wilson Observatory above Pasadena and used the world's most powerful telescope to peer deeper into the universe than anyone had before. Making excruciatingly careful measurements of the galaxies he could see beyond the Milky Way, Hubble was astonished to learn that they weren't stationary at all. The galaxies - the raisins in the bread dough - were in motion, each moving apart from the other. The dough was rising in all directions, and the raisins were going along for the ride..."
NanotubeYarns Twist Like Muscles
|12:25:17 AM, Monday, October 17, 2011|
"Yarns made of the tiny straws of carbon called nanotubes have an astounding ability to twist as they contract, scientists have found.
The effect, reported in Science, is similar to the action of muscles found in elephant trunks and squid tentacles.
However, the yarns twist 1,000 times as much as previous "artificial muscles".
The effect, which occurs thanks to a conducting fluid in which the yarns were dipped, could be put to use in motors much thinner than a human hair.
The team of researchers from Australia, the US, Canada and South Korea demonstrated motors that could spin at nearly 600 revolutions per minute, turning a weight 2,000 times heavier than the yarn itself.
Carbon nanotubes have only recently been identified by scientists; they are "straws" made only of atoms of carbon linked together in hexagons. They have remarkable physical properties - being more than 100 times stronger than steel.
Ray Baughman of the University of Texas at Dallas is a renowned researcher into the tubes' properties, and is a co-author of the new research.
"The carbon nanotube yarns comprise invididual nanotubes - untold billions of them - that are about 1/100,000th the diameter of a human hair," he told the podcast of Science magazine.
The yarns were made by pulling sheets of nanotubes from "forests" of the tubes and twisting them to form a coiled structure - much as yarn is made from wool.
They were then dipped in an electrolyte - a fluid containing ions, electrically charged atoms. When a voltage was applied at the ends of the yarns, these ions moved into the fibres, causing them to expand..."
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