Saturday, February 26, 2011

Premature Aging Replicated in the Lab

The current pace of population aging is without parallel in human history but surprisingly little is known about the human aging process, because lifespans of eight decades or more make it difficult to study. Now, researchers at the Salk Institute for Biological Studies have replicated premature aging in the lab, allowing them to study aging-related disease in a dish.

In the February 23, 2011 advance online edition of the journal Nature, Juan Carlos Izpisúa Belmonte, Ph.D. a professor in the Salk Institute's Gene Expression Laboratory, and his team report that they have successfully generated induced pluripotent stem (iPS) cells from skin cells obtained from patients with Hutchinson-Gilford Progeria Syndrome -- who age eight to 10 times faster than the rest of us -- and differentiated them into smooth muscle cells displaying the telltale signs of vascular aging.
"The slow progression and complexity of the aging process makes it very hard to study the pathogenesis of cardiovascular and other aging-related disorders," says Izpisúa Belmonte. "Having a human model of accelerated aging will facilitate the development of treatments and possibly a cure for Progeria and give us new insights into how we age. It may also help prevent or treat heart disease in the general aging population."
Progeria's striking features resemble the aging process put on fast-forward and afflicted people rarely live beyond 13 years. Almost all of the patients die from complications of arteriosclerosis -- the clogging or hardening of arteries or blood vessels caused by plaques -- which leads to heart attack and stroke.
Scientists are particularly interested in Progeria in the hopes that it might reveal clues to the normal human aging process. However, the disease is exceedingly rare and only 64 children living with Progeria are known making access to patients very difficult.
Hutchinson-Gilford Progeria Syndrome is caused by a single point mutation in the gene encoding lamin A, which forms a protein scaffold on the inner edge of the nucleus that helps maintain chromatin structure and organize nuclear processes such as RNA and DNA synthesis. The mutation creates an alternative splice site that leads to the production of a truncated version of the protein known as progerin. Unlike the full-length protein, progerin does not properly integrate into the nuclear lamina, which disrupts the nuclear scaffold and causes a host of problems.
"There is also evidence that defective lamin A accumulates during the normal aging process via the sporadic use of the alternative splice site, " explains Izpisua Belmonte. "Therefore we are very keen on using our in vitro iPS cell-based model to identify new aging markers and explore other aspects of human premature and physiological aging."
Compared to normal skin fibroblasts, cells from Progeria patients have misshapen nuclei and a range of other nuclear defects, including a disorganized nuclear lamina, loss of super-condensed DNA, telomere shortening and genomic instability. Yet, despite their "old" appearance and characteristics, these cells could be readily converted into iPS cells.
"The reprogramming process erased all nuclear and epigenetic defects and the rejuvenated pluripotent cells looked and acted like perfectly normal healthy cells," says first author Guang-Hui Liu, Ph.D., a postdoctoral researcher in the Belmonte lab.
Since lamin A is only expressed in differentiated cells but is absent from embryonic stem cells, he wondered whether iPS cells produce lamin A and/or progerin, which should follow the same expression pattern as lamin A. In his experiments, he couldn't detect either one. "The biological clock is reset in these cells because lamin A is silenced," explains Liu.
As soon as the Salk researchers differentiated Progeria-derived iPS cells, progerin expression was reactivated. "This reversible suppression of progerin expression by reprogramming and subsequent reactivation during differentiation, provides a unique model system to study human premature aging pathologies," says Izpisúa Belmonte.
Progerin accumulates mainly in smooth muscle cells found within the walls of arterial blood vessels, and vascular smooth muscle cells degeneration is one of the hallmarks of Hutchinson-Gilford Progeria Syndrome-associated arteriosclerosis. In fact, vascular smooth muscle cell senescence also plays a role in advanced arteriosclerosis within the normal aging population.
Upon directed differentiation of Progeria-derived iPS cells into smooth muscle cells the premature aging phenotype, including misshapen nuclei, the loss of gene silencing marks and compromised proliferation, reappeared. Genetically modifying progeria-derived iPS cells to shut down the expression of progerin staved off the premature appearance of aging phenotypes after differentiation. "Transplantation of the progenitor cells derived from the "corrected" progeria iPS cells might hold the promise to treat these progeria children in the future." says Liu.
Other researchers contributing the study include Basam Z. Barkho, Sergio Ruiz, Jing Qu, Scheng-Liang Yang, Athanasia D. Panopoulos, Keiichiro Suzuki, Leo Kuraian, Christopher Walsh and Ignacio Sancho-Martinez in the Gene Expression Laboratory at the Salk Institute, Dinh Diep and Ho Lim Fung in the Department of Engineering at the University of California, San Diego, James Thompson and John Yates III in the Department of Cell Biology at the Scripps Research Institute and Stephanie Boue at the Center for Regenerative Medicine in Barcelona.
The study was supported by the California Institute of Regenerative Medicine, the AFAR/Ellison Medical Foundation, the G. Harold and Leila Y. Mathers Charitable Foundation, Sanofi-Aventis, MICINN, the Fundacion Cellex and grants from the National Institutes of Health.

Left: Juan Carlos Izpisúa Belmonte, Ph.D. a professor in the Salk Institute's Gene Expression

Solar Experts Detect Waves in Giant Magnetic Holes the Size of the UK

ScienceDaily (Feb. 25, 2011) — Massive waves in giant magnetic holes on the surface of the Sun have been discovered for the first time by solar scientists from the University of Sheffield and Queen´s University Belfast, something that will bring experts a step closer to unlocking the secrets of the Sun.

The Sun is interwoven by a complex network of magnetic field lines that are responsible for a large variety of fascinating features that can be seen in the solar atmosphere. Large, dark regions, which look like holes on the Sun´s surface, mark out areas where the magnetic field breaks through from the Sun´s deep, boiling interior and rises into the very hot solar atmosphere, which is over a million degrees. The largest of these dark regions are often called sunspots and have been studied since their discovery from as early as 364 BC.
Led by Professor Robertus von Fay-Siebenburgen, Head of the Solar Physics and Space Plasma Research Centre (SP2RC) at the University of Sheffield, the team studied a magnetic region of the Sun much smaller than a sunspot, however its size was still many times greater than the size of the UK.
Their research, which was published this week in Astrophysical Journal, has shown that the magnetic hole they observed, which is also known as a pore, is able to channel energy generated deep inside the Sun, along the magnetic field to the Sun´s upper atmosphere. The magnetic field emerging through the pore is over 1,000 times stronger than the magnetic field of Earth.The energy being transported is in the form of a very special form of waves, known as `sausage waves´ which the scientists were able to observe using a UK-built solar imager known as ROSA (Rapid Oscillations of the Solar Atmosphere), which was designed by Queen´s University Belfast and is in operation at the Dunn Solar Telescope, Sacramento Peak, USA. This is the first direct observation of `sausage waves´ at the solar surface. The magnetic hole is seen to increase and decrease in size periodically which is a characteristic feature of the `sausage wave.´
The team of experts, including Dr Richard Morton from the University of Sheffield, as well as Professor Mihalis Mathioudakis and Dr David Jess from Queen´s University Belfast, hope these giant magnetic holes will play an important role in unveiling the longstanding secrets behind solar coronal heating.
This is because the solar surface has a temperature of a few thousand degrees but the solar corona -- the outermost, mysterious, and least understood layer of the Sun's atmosphere -- is heated to temperatures often a thousand times hotter than the surface. Why the temperature of the Sun´s atmosphere increases as we move further away from the centre of energy production, which lies under the surface, is a great mystery of astrophysics. The findings, which demonstrate the transfer of energy on a massive scale, offer a new explanation for this puzzle.
The team now hope to use further similar solar images from ROSA to understand the fine substructure of these massive magnetic holes by reconstructing the images to view what is inside the holes.
Professor Robertus von Fay-Siebenburgen, said: "This is a fascinating new discovery in line with a number of discoveries made in recent years by the team. It is the first time that `sausage waves´ have been detected in the Sun with such detail. Analysing these waves may bring us closer to understanding the physical mechanisms in the atmosphere of a star.

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This shows the chromosphere of the solar atmosphere. Bright patches correspond to concentrated magnetic flux.

Gas Rich Galaxies Confirm Prediction of Modified Gravity Theory

ScienceDaily (Feb. 25, 2011) — Recent data for gas rich galaxies precisely match predictions of a modified theory of gravity known as MOND, according to a new analysis by University of Maryland Astronomy Professor Stacy McGaugh. This -- the latest of several successful MOND predictions -- raises new questions about accuracy of the reigning cosmological model of the universe, writes McGaugh in a paper to be published in March in Physical Review Letters.

Modern cosmology says that for the universe to behave as it does, the mass-energy of the universe must be dominated by dark matter and dark energy. However, direct evidence for the existence of these invisible components remains lacking. An alternate, though unpopular, possibility is that the current theory of gravity does not suffice to describe the dynamics of cosmic systems.
A few theories that would modify our understanding of gravity have been proposed. One of these is Modified Newtonian Dynamics (MOND), which was hypothesized in 1983 by Moti Milgrom a physicist at the Weizmann Institute of Science in Rehovot, Israel. One of MOND's predictions specifies the relative relationship between the mass of any galaxy and its flat rotation velocity. However, uncertainties in the estimates of masses of stars in star-dominated spiral galaxies (such as our own Milky Way) previously had precluded a definitive test.
To avoid this problem, McGaugh examined gas rich galaxies, which have relatively fewer stars and a preponderance of mass in the form of interstellar gas. "We understand the physics of the absorption and release of energy by atoms in the interstellar gas, such that counting photons is LIKE counting atoms. This gives us an accurate estimate of the mass of such galaxies," McGaugh said.
Using recently published work that he and other scientists had done to determine both the mass and flat rotation velocity of many gas rich galaxies, McGaugh compiled a sample of 47 of these and compared each galaxy's mass AND rotation velocity with the relationship expected by MOND. All 47 galaxies fell on or very close to the MOND prediction. No dark matter model performed as well.
"I find it remarkable that the prediction made by Milgrom over a quarter century ago performs so well in matching these findings for gas rich galaxies," McGaugh said. "
MOND vs. Dark Matter -- Dark Energy
Almost everyone agrees that on scales of large galaxy clusters and up, the Universe is well described by dark matter -- dark energy theory. However, according to McGaugh this cosmology does not account well for what happens at the scales of galaxies and smaller.
"MOND is just the opposite," he said. "It accounts well for the 'small' scale of individual galaxies, but MOND doesn't tell you much about the larger universe.
Of course, McGaugh said, one can start from the assumption of dark matter and adjust its models for smaller scales until it fits the current finding. "This is not as impressive as making a prediction ahead of [new findings], especially since we can't see dark matter. We can make any adjustment we need." This is rather like fitting planetary orbits with epicycles," he said. Epicycles were erroneously used by the ancient Greek scientist Ptolemy to explain observed planetary motions within the context of a theory for the universe that placed Earth in its center.
"If we're right about dark matter, why does MOND work at all?" asks McGaugh. "Ultimately, the correct theory -- be it dark matter or a modification of gravity -- needs to explain this."

The star dominated spiral galaxy UGC 2885. (Credit: Zagursky & McGaugh)

Thursday, February 24, 2011

Rocket-related Issue Pushes Glory Launch into March

: The Taurus XL launch for NASA's Glory spacecraft from Vandenberg Air Force Base has been delayed due to technical issues. Credit: U.S. Air Force photo Enlarge Image

WASHINGTON — NASA has temporarily suspended preparations to launch its Glory climate observation satellite after a malfunction occurred with the ground support equipment for the Taurus XL rocket that will carry the satellite into its polar orbit, the agency announced Feb. 24.

About 15 minutes before Glory was to launch Feb. 23, launch managers received a false indication about the status of the rocket, NASA said in a press release. The source of the problem has not yet been identified, and NASA is now evaluating possible launch opportunities in early to mid-March, it said.

The Glory satellite, built by Orbital Sciences Corp. of Dulles, Va., is designed to study solar irradiance and aerosol particles in the Earth’s atmosphere that are believed to be associated with global climate change.

The Taurus XL rocket, also built by Orbital Sciences, is making its return to flight two years after a launch failure that destroyed NASA’s Orbiting Carbon Observatory satellite.

Ancient fossil sheds light on early evolution of body armor

‘Walking cactus’ appears to have been first of its kind to stride on bendable, hard-covered legs

By Susan Milius

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MEET SPIKYA depiction of the 520-million-year-old fossil Diania cactiformis in life. The front of the animal is to the left.J. Liu

Fossils of an ancient “walking cactus” suggest how ancestors of today’s lobsters, insects, spiders and related groups went from squishy to spiky.
Dating back about 520 million years, the fossilized prickly creature is not a plant but a thumb-sized, wormlike animal with 10 pairs of long, sturdy legs, says Jianni Liu of Northwest University in Xi’an, China. Discovered in southwestern China, it probably scuttled along the bottom of shallow seas, she says. In the Feb. 24 Nature, she and her colleagues christen the species Diania cactiformis, in honor of its spiky look.
Its armored leggy look surprised Liu when she first saw it. “I fell in love with this strange guy,” she says. “Later when I observed it carefully under the microscope, I realized it was not only a funny one but an important one.”

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WHAT LEGSOne of the best-preserved fossils of the newly named Diania cactiformis reveals spiky legs that researchers interpret as having hard outer coverings and joints.J. Liu

The creature’s 10 legs appear to have carried a hard, outer covering of armor and joints that let them bend. Those features would make the species the earliest known worm-with-legs to have a hardened outer covering and also the first to have jointed legs, Liu says. An armored outer skeleton and jointed legs today distinguish the arthropods, the major lineage including crustaceans, insects, spiders and mites. Thus the cactus sea creature might be a sister to arthropod ancestors.
“The significance of the find is that arthropods are, in terms of species, the most successful group on the planet,” Liu says. “The secret of their success seems to be their legs.” Ancient appendages evolved with diverse lifestyles, forming claws for example, or gilled structures for underwater life. Even legs for moving around diversified into paddles for swimming or launchers for jumping.
Liu points out that paleontologists pursuing the history of the remarkable arthropod legs have debated such puzzles as whether the armored bodies came before or after armored legs.
The presumably armored legs of this animal show how a legs-first scenario might look, but Liu notes that there’s no evidence that this is a direct ancestor of modern arthropods.
Jan Bergström of the Swedish Museum of Natural History in Stockholm laments the fact that it’s not a direct ancestor, but says the new fossil “fills a hole in the evolutionary mosaic.”

Ancient Catastrophic Drought Leads to Question: How Severe Can Climate Change Become?

ScienceDaily (Feb. 24, 2011) — How severe can climate change become in a warming world? Worse than anything we've seen in written history, according to results of a study recently appearing in the journal Science.

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An international team of scientists led by Curt Stager of Paul Smith's College, New York, has compiled four dozen paleoclimate records from sediment cores in Lake Tanganyika and other locations in Africa.
The records show that one of the most widespread and intense droughts of the last 50,000 years or more struck Africa and Southern Asia 17,000 to 16,000 years ago.
Between 18,000 and 15,000 years ago, large amounts of ice and meltwater entered the North Atlantic Ocean, causing regional cooling but also major drought in the tropics, says Paul Filmer, program director in the National Science Foundation's (NSF) Division of Earth Sciences, which funded the research along with NSF's Division of Atmospheric and Geospace Sciences and its Division of Ocean Sciences.
"The height of this time period coincided with one of the most extreme megadroughts of the last 50,000 years in the Afro-Asian monsoon region with potentially serious consequences for the Paleolithic humans that lived there at the time," says Filmer.
The "H1 megadrought," as it's known, was one of the most severe climate trials ever faced by anatomically modern humans.
Africa's Lake Victoria, now the world's largest tropical lake, dried out, as did Lake Tana in Ethiopia, and Lake Van in Turkey.
The Nile, Congo and other major rivers shriveled, and Asian summer monsoons weakened or failed from China to the Mediterranean, meaning the monsoon season carried little or no rainwater.
What caused the megadrought remains a mystery, but its timing suggests a link to Heinrich Event 1 (or "H1"), a massive surge of icebergs and meltwater into the North Atlantic at the close of the last ice age.
Previous studies had implicated southward drift of the tropical rain belt as a localized cause, but the broad geographic coverage in this study paints a more nuanced picture.
"If southward drift were the only cause," says Stager, lead author of the Science paper, "we'd have found evidence of wetting farther south. But the megadrought hit equatorial and southeastern Africa as well, so the rain belt didn't just move--it also weakened."
Climate models have yet to simulate the full scope of the event.
The lack of a complete explanation opens the question of whether an extreme megadrought could strike again as the world warms and de-ices further.
"There's much less ice left to collapse into the North Atlantic now," Stager says, "so I'd be surprised if it could all happen again--at least on such a huge scale."
Given what such a catastrophic megadrought could do to today's most densely populated regions of the globe, Stager hopes he's right.
Stager also holds an adjunct position at the Climate Change Institute, University of Maine, Orono.
Co-authors of the paper are David Ryves of Loughborough University in the United Kingdom; Brian Chase of the Institut des Sciences de l'Evolution de Montpellier in France and the Department of Archaeology, University of Bergen, Norway; and Francesco Pausata of the Geophysical Institute, University of Bergen, Norway.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

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A wetland along Lake Victoria today, analogous to ancient drought conditions. (Credit: Curt Stager)

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Apple shareholders nix CEO succession disclosure

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CUPERTINO, Calif.--Apple shareholders today rejected a proposal that would have required the company to disclose its succession plan for senior management.
The proposal was one of two by shareholders aimed at adding transparency and a new voting standard to what is considered one of the most secretive technology companies. In its proxy materials ahead of the meeting, Apple's board had urged shareholders to vote against both proposals.

As expected, Jobs was not present during the meeting. In his place was Chief Operating Officer Tim Cook, who has filled in for Jobs since January when Jobs, a pancreatic cancer survivor who has received a liver transplant, announced his latest medical leave.
A group of shareholders had asked the company to reveal its plans for replacing Jobs, a request Apple had rallied against, saying such a revelation would give competitors an "unfair advantage" by publicizing the company's confidential objectives and plans. Nonetheless, earlier in the month Institutional Shareholder Services endorsed the proposal, which was originally put forward by the Central Laborers' Pension Fund, a holder of about 11,500 shares of Apple stock.
The second proposal, which concerned majority voting of board members, passed, giving share owners the power to cast Nay votes against unopposed directors. Apple said its objection to the measure was based on differences in majority voting requirements by state, which, the company said, could add a "layer of complexity" to implementation.
During the question and answer session that followed, Cook was joined on stage by Phil Schiller, senior vice president of worldwide product marketing, and Peter Oppenheimer, senior vice president and CFO. Cook talked up Apple's services over the past year, including its opening of 44 new retail stores and shipping of 40 million iPhones, doubling unit sales from the previous year. Cook also said the company had made great advances in China, tripling revenue there since last year.

Pixelated motif on signage at Apple's Cupertino, Calif., campus.

(Credit: Josh Lowensohn/CNET)

Cook paid special attention to iOS, including the iPhone and iPad, saying that the OS continued to be "years ahead" of competitors' platforms. Cook also brought up next week's press event, saying that the invitation had provided some clues about what Apple planned to announce. Even so, audience members peppered the company about its strategic plans for iOS, including things like whether it would ever allow plug-ins, or how Apple could avoid the sort of hardware-specific software distribution limitations it experienced during the Mac versus PC era in the early '90s, which went Microsoft's way.
Schiller responded by saying that that had been "a different time," and that the iPhone was a "post-PC" product. Apple's senior vice president of iOS Software, Scott Forstall, jumped in on the third-party plug-ins question, saying that plug-ins had been kept off the platform for stability and security, citing some of the difficulties in moving from Mac OS 7 to 8 as being a leading factor in that decision.
One audience member also brought up the conditions for workers at overseas factories where Apple products were produced, as well as asking if Cook, Schiller, or Oppenheimer had seen the play "The Agony and Ecstasy of Steve Jobs," playing about an hour away from Apple's campus, at the Berkeley Repertory Theatre. All three said they hadn't, with Schiller seeming visibly frustrated by the question.
Cook followed by offering details about Apple's considerable efforts to go through its supply chain to find problems that could be fixed, as well as noting that the company had helped reimburse close to $300 million in fees paid by workers. "I am really proud of the changes we've forced," Cook said.
Also of special interest was a question about whether Apple would ever offer a way for consumers to ditch their television sets to watch streaming TV shows on their computers instead. Schiller answered by saying that Apple was always adding "new types" of media. Even so, he said, counting out the TV at this point for live events would be a rash decision.
And speaking of entertainment devices, Cook fielded a question about whether Apple had plans to get more serious about gaming, particularly with a dedicated device, by saying that the company was already in the gaming business with the iPod Touch, and had great success with a large library of games on the App Store. "There's a segment who are using it as a primary gaming device," he said. "We think that's a good place to be, where we are right now."
One audience member also questioned what Apple was up to with its license of Liquidmetal, a query Cook politely shot down, saying the company does not discuss what it does with its investments short of saying that such investments were often for personnel, infrastructure, and intellectual property.

Tuesday, February 22, 2011

Earth's Core Rotation Faster Than Rest of the Planet, but Slower Than Previously Believed

ScienceDaily (Feb. 22, 2011) — New research gives the first accurate estimate of how much faster Earth's core is rotating compared to the rest of the planet.

Previous research had shown that Earth's core rotates faster than the rest of the planet. However, scientists from the University of Cambridge have discovered that earlier estimates of 1 degree every year were inaccurate and that the core is actually moving much slower than previously believed -- approximately 1 degree every million years. Their findings are published on 20 February, in the journal Nature Geoscience.
The inner core grows very slowly over time as material from the fluid outer core solidifies onto its surface. During this process, an east-west hemispherical difference in velocity is frozen into the structure of the inner core.
"The faster rotation rates are incompatible with the observed hemispheres in the inner core because it would not allow enough time for the differences to freeze into the structure," said Lauren Waszek, first author on the paper and a PhD student from the University of Cambridge's Department of Earth Sciences. "This has previously been a major problem, as the two properties cannot coexist. However, we derived the rotation rates from the evolution of the hemispherical structure, and thus our study is the first in which the hemispheres and rotation are inherently compatible."
For the research, the scientists used seismic body waves which pass through the inner core -- 5200km beneath the surface of Earth -- and compared their travel time to waves which reflect from the inner core surface. The difference between the travel times of these waves provided them with the velocity structure of the uppermost 90 km of the inner core.
They then had to reconcile this information with the differences in velocity for the east and west hemispheres of the inner core. First, they observed the east and west hemispherical differences in velocity. They then constrained the two boundaries which separate the hemispheres and found that they both shifted consistently eastward with depth. Because the inner core grows over time the deeper structure is therefore older, and the shift in the boundaries between the two hemispheres results in the inner core rotating with time. The rotation rate is therefore calculated from the shift of the boundaries and the growth rate of the inner core.
Although the inner core is 5200km beneath our feet, the effect of its presence is especially important on Earth's surface. In particular, as the inner core grows, the heat released during solidification drives convection in the fluid in the outer core. This convection generates Earth's geomagnetic field. Without our magnetic field, the surface would not be protected from solar radiation, and life on Earth would not be able to exist.
"This result is the first observation of such a slow inner core rotation rate," said Waszek "It therefore provides a confirmed value which can now be used in simulations to model the convection of the Earth's fluid outer core, giving us additional insight into the evolution of our magnetic field."
The paper 'Reconciling the hemispherical structure of Earth's inner core with its super-rotation' is scheduled for advanced online publication in Nature Geoscience on 20 February

New High-Resolution Method for Imaging Below the Skin Using a Liquid Lens

ScienceDaily (Feb. 20, 2011) — University of Rochester optics professor Jannick Rolland has developed an optical technology that provides unprecedented images under the skin's surface. The aim of the technology is to detect and examine skin lesions to determine whether they are benign or cancerous without having to cut the suspected tumor out of the skin and analyze it in the lab. Instead, the tip of a roughly one-foot-long cylindrical probe is placed in contact with the tissue, and within seconds a clear, high-resolution, 3D image of what lies below the surface emerges.

Rolland presented her findings at the 2011 annual meeting of the American Association for the Advancement of Science in Washington, D.C., on Feb. 19.
"My hope is that, in the future, this technology could remove significant inconvenience and expense from the process of skin lesion diagnosis," Rolland says. "When a patient walks into a clinic with a suspicious mole, for instance, they wouldn't have to have it necessarily surgically cut out of their skin or be forced to have a costly and time-consuming MRI done. Instead, a relatively small, portable device could take an image that will assist in the classification of the lesion right in the doctor's office."
The device accomplishes this using a unique liquid lens setup developed by Rolland and her team for a process known as Optical Coherence Microscopy. In a liquid lens, a droplet of water takes the place of the glass in a standard lens. As the electrical field around the water droplet changes, the droplet changes its shape and therefore changes the focus of the lens. This allows the device to take thousands of pictures focused at different depths below the skin's surface. Combining these images creates a fully in-focus image of all of the tissue up to 1 millimeter deep in human skin, which includes important skin tissue structures. Because the device uses near infrared light instead of ultrasounds, the images have a precise, micron-scale resolution instead of a millimeter-scale resolution.
The process has been successfully tested in in-vivo human skin and several papers on it have been published in peer-reviewed journals. Rolland says that the next step is to start using it in a clinical research environment so its ability to discriminate between different types of lesions may be assessed.
Rolland joined the faculty of the Hajim School of Engineering and Applied Science's Institute of Optics in 2009. She is the Brian J. Thompson Professor of Optical Engineering and is also a professor of biomedical engineering and associate director of the R.E. Hopkins Center for Optical Design and Engineering.

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This prototype device developed by University of Rochester Professor of Optical Engineering Jannick Rolland can take high-resolution images under the skin's surface without removing the skin. Researchers say that in the future it may eliminate the need for many biopsies to detect skin cancer. (Credit: J. Adam Fenster)

carbon Sink at South Pole Has Grown Recently, Historical Collections Reveal

Reveal

ScienceDaily (Feb. 21, 2011) — By studying collections of a marine bryozoan that date back to a famous 1901 expedition to the South Pole, researchers have found that those organisms were growing steadily up until 1990, when their growth more than doubled.

The data, reported in the February 22 issue of Current Biology, provide the highest-latitude record of a century of growth and some of the first evidence that polar carbon sinks may be increasing.
The bryozoan in question, known as Cellarinella nutti, is a filter-feeding invertebrate that looks like branching twigs. C. nutti is found in abundance in the Antarctic and is ideal for such studies because it preserves a clear macroscopic environmental record in its skeleton, recorded as tree-ring-like growth-check lines.
"This is one of the few pieces of evidence that life in Antarctica has recently changed drastically," said David Barnes of the British Antarctic Survey. "These animals are taking more carbon dioxide out of circulation and locking it away on the seabed."
The more rapid growth of C. nutti reflects a coincident increase in the regional production of the phytoplankton that the bryozoan eats. Those algae rely on carbon dioxide dissolved into the seawater for their sustenance. The carbon in the algae is taken up by C. nutti, where it is incorporated into their skeleton and other tissues. As the animals grow, portions of it break off and are buried in the seabed. "Thus, the amount of carbon being buried on the seabed is increasing -- whilst globally we are becoming more aware of the need to reduce carbon dioxide in the atmosphere," Barnes said.
He says the shift is most likely the result of ozone losses, which have led to an increase in wind speeds over the last decade. Those stronger winds are a boon to plankton, as they blow ice out of the way and drive greater circulation of surface waters.
"If we are right, this is a rare example of animals responding to one global phenomenon, the ozone hole, and affecting another, the greenhouse effect," Barnes said.
The discovery would not have been possible without early marine collections assembled by the explorer Captain Robert Falcon Scott, a polar pioneer who led the British National Antarctic Expedition and British Antarctic Expeditions at the turn of the 20th century, along with specimens maintained by museums in the United Kingdom, United States, and New Zealand.
"Scott's most famous journey was to reach the South Pole, but a team lead by the Norwegian explorer [Roald] Amundsen beat them to it," Barnes said. "Scott's team died in 1912 on the journey back to his food depots, and so his exploits are often not associated with success. What is not so well known is that his voyages were first and foremost scientific ones, and the collections of material and information they made were impressive even by today's standards."
The findings highlight the challenges of understanding the effects of large-scale processes such as the ozone hole or climate change. "This is not just because it is patchy in space and time, but also because of interactions between effects, as we found," Barnes said.
It is not yet clear how big an impact the changes in C. nutti might have, and at the moment, Barnes suspects it is likely to be quite small.
"Nevertheless, we think that the combination of ice shelf losses and sea ice losses due to climate change and the effect of ozone loss-induced wind speeds offer some hope for much-needed carbon sequestration to the seabed in the Southern Ocean," Barnes said. "There are few other places in the world where global and regional changes could actually lead to more carbon being removed from the system."

Engineering Atomic Interfaces for New Electronics

ScienceDaily (Feb. 17, 2011) — Most people cross borders such as doorways or state lines without thinking much about it. Yet not all borders are places of limbo intended only for crossing. Some borders, like those between two materials that are brought together, are dynamic places where special things can happen.

For an electron moving from one material toward the other, this space is where it can join other electrons, which together can create current, magnetism or even light.
A multi-institutional team has made fundamental discoveries at the border regions, called interfaces, between oxide materials. Led by University of Wisconsin-Madison materials science and engineering professor Chang-Beom Eom, the team has discovered how to manipulate electrons in oxide interfaces by inserting a single layer of atoms. The researchers also have discovered unusual electron behaviors at these engineered interfaces.
Their work, which is sponsored by the National Science Foundation, is published Feb. 18 in the journal Science and could allow researchers to further study and develop interfaces with a wide array of properties.
Eom's team blends theorists and experimentalists, including UW-Madison physics professor Mark Rzchowski and collaborators at the University of Nebraska-Lincoln, University of Michigan, Argonne National Laboratory and Brookhaven National Laboratory.
The researchers used two pieces of precisely grown strontium titanate, which is a type of oxide, or compound with oxygen as a fundamental element. Between the pieces, the researchers inserted a one-atom-thick layer of one of five rare-earth elements, which are important components in the electronics industry.
The team found that the rare-earth element layer creates an electron gas that has some interesting characteristics. The gas actually behaves more like an electron "liquid," since the electrons move more in tandem, or in correlation, than a gas normally does.
"If you take two materials, each has different characteristics, and if you put them together, at their interface you may find something unexpected," Eom says.
This research is the first demonstration of strong correlation among electrons at an oxide interface. The electron layer displayed distinct characteristics depending on the particular rare-earth element the team used. Materials with larger ionic radii, such as lanthanum, neodymium and praseodymium, are conducting, whereas materials with smaller radii, including samarium and yttrium, are insulating.
The insulating elements form an electron gas that can be compared to a thick liquid, somewhat like honey. The higher viscosity (basically, thickness) means the electrons can't move around as freely, making them more insulating. Conversely, the conducting elements form a gas that is a "liquid" more like gasoline; the viscosity is lower, so the electrons can move more freely and are better conductors.
Prior to this research, scientists knew extra electrons could reside at interfaces, but they didn't realize the complexity of how the electrons then behaved together at those interfaces.
The discovery of liquid-like behavior in the electron layer could open up an entire field of interfacial engineering for other scientists to explore, as well as new applications that take advantage of electron interactions. Since Eom and his colleagues developed an understanding of the basic physics behind these behaviors, their work could be expanded to create not only conductive or insulating interfaces, but also magnetic or optical ones.
Though scientists previously have looked at semiconductor interfaces, Eom's team is the first to specifically address those that use oxide interfaces to control conducting states with a single atomic layer. Oxides make up a class of materials including millions of compounds, and each has its own unique set of properties. The ability to manipulate various oxide interfaces could give rise to new generations of materials, electronics and other devices.
"This advancement could make a broad impact in fields even beyond physics, materials or chemistry," Eom says. "People can use the idea that an interface made from a single atomic layer of different ions can be used to create all kinds of properties."

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Researchers have discovered how to manipulate electrons in oxide interfaces by inserting a single layer of atoms. (Credit: iStockphoto/Martin McCarthy)

Monday, February 21, 2011

Can WISE Find the Hypothetical 'Tyche' Planet at Edge of Our Solar System?

ScienceDaily (Feb. 21, 2011) — In November 2010, the scientific journal Icarus published a paper by astrophysicists John Matese and Daniel Whitmire, who proposed the existence of a binary companion to our sun, larger than Jupiter, in the long-hypothesized "Oort cloud" -- a faraway repository of small icy bodies at the edge of our solar system. The researchers use the name "Tyche" for the hypothetical planet. Their paper argues that evidence for the planet would have been recorded by the Wide-field Infrared Survey Explorer (WISE).

WISE is a NASA mission, launched in December 2009, which scanned the entire celestial sky at four infrared wavelengths about 1.5 times. It captured more than 2.7 million images of objects in space, ranging from faraway galaxies to asteroids and comets relatively close to Earth. Recently, WISE completed an extended mission, allowing it to finish a complete scan of the asteroid belt, and two complete scans of the more distant universe, in two infrared bands. So far, the mission's discoveries of previously unknown objects include an ultra-cold star or brown dwarf, 20 comets, 134 near-Earth objects (NEOs), and more than 33,000 asteroids in the main belt between Mars and Jupiter.
Following its successful survey, WISE was put into hibernation in February 2011. Analysis of WISE data continues. A preliminary public release of the first 14 weeks of data is planned for April 2011, and the final release of the full survey is planned for March 2012.
Frequently Asked Questions
Q: When could data from WISE confirm or rule out the existence of the hypothesized planet Tyche?
A: It is too early to know whether WISE data confirms or rules out a large object in the Oort cloud. Analysis over the next couple of years will be needed to determine if WISE has actually detected such a world or not. The first 14 weeks of data, being released in April 2011, are unlikely to be sufficient. The full survey, scheduled for release in March 2012, should provide greater insight. Once the WISE data are fully processed, released and analyzed, the Tyche hypothesis that Matese and Whitmire propose will be tested.
Q: Is it a certainty that WISE would have observed such a planet if it exists?
A: It is likely but not a foregone conclusion that WISE could confirm whether or not Tyche exists. Since WISE surveyed the whole sky once, then covered the entire sky again in two of its infrared bands six months later, WISE would see a change in the apparent position of a large planet body in the Oort cloud over the six-month period. The two bands used in the second sky coverage were designed to identify very small, cold stars (or brown dwarfs) -- which are much like planets larger than Jupiter, as Tyche is hypothesized to be.
Q: If Tyche does exist, why would it have taken so long to find another planet in our solar system?
A: Tyche would be too cold and faint for a visible light telescope to identify. Sensitive infrared telescopes could pick up the glow from such an object, if they looked in the right direction. WISE is a sensitive infrared telescope that looks in all directions.
Q: Why is the hypothesized object dubbed "Tyche," and why choose a Greek name when the names of other planets derive from Roman mythology?
A: In the 1980s, a different companion to the sun was hypothesized. That object, named for the Greek goddess "Nemesis," was proposed to explain periodic mass extinctions on Earth. Nemesis would have followed a highly elliptical orbit, perturbing comets in the Oort Cloud roughly every 26 million years and sending a shower of comets toward the inner solar system. Some of these comets would have slammed into Earth, causing catastrophic results to life. Recent scientific analysis no longer supports the idea that extinctions on Earth happen at regular, repeating intervals. Thus, the Nemesis hypothesis is no longer needed. However, it is still possible that the sun could have a distant, unseen companion in a more circular orbit with a period of a few million years -- one that would not cause devastating effects to terrestrial life. To distinguish this object from the malevolent "Nemesis," astronomers chose the name of Nemesis's benevolent sister in Greek mythology, "Tyche."
JPL manages and operates the Wide-field Infrared Survey Explorer for NASA's Science Mission Directorate, Washington. The principal investigator, Edward Wright, is at UCLA. The mission was competitively selected under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory, Logan, Utah, and the spacecraft was built by Ball Aerospace & Technologies Corp., Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA. More information is online at

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

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This colorful picture is a mosaic of the Lagoon nebula taken by NASA's Wide-field Infrared Survey Explorer, or WISE. (Credit: NASA/JPL-Caltech/UCLA)

Scientists Steer Car With the Power of Thought

ScienceDaily (Feb. 21, 2011) — You need to keep your thoughts from wandering, if you drive using the new technology from the AutoNOMOS innovation labs of Freie Universität Berlin. The computer scientists have developed a system making it possible to steer a car with your thoughts. Using new commercially available sensors to measure brain waves -- sensors for recording electroencephalograms (EEG) -- the scientists were able to distinguish the bioelectrical wave patterns for control commands such as "left," "right," "accelerate" or "brake" in a test subject.

They then succeeded in developing an interface to connect the sensors to their otherwise purely computer-controlled vehicle, so that it can now be "controlled" via thoughts. Driving by thought control was tested on the site of the former Tempelhof Airport.
The scientists from Freie Universität first used the sensors for measuring brain waves in such a way that a person can move a virtual cube in different directions with the power of his or her thoughts. The test subject thinks of four situations that are associated with driving, for example, "turn left" or "accelerate." In this way the person trained the computer to interpret bioelectrical wave patterns emitted from his or her brain and to link them to a command that could later be used to control the car. The computer scientists connected the measuring device with the steering, accelerator, and brakes of a computer-controlled vehicle, which made it possible for the subject to influence the movement of the car just using his or her thoughts.
"In our test runs, a driver equipped with EEG sensors was able to control the car with no problem -- there was only a slight delay between the envisaged commands and the response of the car," said Prof. Raúl Rojas, who heads the AutoNOMOS project at Freie Universität Berlin. In a second test version, the car drove largely automatically, but via the EEG sensors the driver was able to determine the direction at intersections.
The AutoNOMOS Project at Freie Universität Berlin is studying the technology for the autonomous vehicles of the future. With the EEG experiments they investigate hybrid control approaches, i.e., those in which people work with machines.
The computer scientists have made a short film about their research, which is available at:

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Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

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Computer scientists have developed a system making it possible to steer a car with your thoughts. (Credit: Image courtesy of Freie Universitaet Berlin)

Plants Cloned as Seeds: Hybrids That Breed True Would Be Major Advance for Crop Plants

Plants have for the first time been cloned as seeds. The research by aUC Davis plant scientists and their international collaborators, published Feb. 18 in the journal Science, is a major step towards making hybrid crop plants that can retain favorable traits from generation to generation.

Most successful crop varieties are hybrids, said Simon Chan, assistant professor of plant biology at UC Davis and an author of the paper. But when hybrids go through sexual reproduction, their traits, such as fruit size or frost resistance, get scrambled and may be lost.
"We're trying to make a hybrid that breeds true," Chan said, so that plants grown from the seed would be genetically identical to one parent.
Some plants, especially fruit trees, can be cloned from cuttings, but this approach is impractical for most crops. Other plants, especially weeds such as hawkweed and dandelions, can produce true seeds that are clones of themselves without sexual reproduction -- a still poorly understood process called apomixis.
The new discovery gets to the same result as apomixis, although by a different route, Chan said.
Normally, eggs and sperm are haploid -- they have half the number of chromosomes of the parent. The fertilized egg and the adult plant it grows into are diploid -- containing a full complement of chromosomes, half contributed by each parent.
Chan and his colleagues focused their work on the laboratory plant Arabidopsis, which has certain genetic mutations that allow it to produce diploid eggs without sexual recombination. These eggs have the same genes and number of chromosomes as their parents. But those eggs cannot be grown into adult plants without fertilization by sperm, which adds another parent's set of chromosomes.
Last year, Chan and UC Davis postdoctoral researcher Maruthachalam Ravi showed that they could breed haploid Arabidopsis plants that carried chromosomes from only one parent. They introduced a genetic change so that after the eggs were fertilized, the chromosomes from one of the parents were eliminated. Such haploid plants would reduce the time needed to breed new varieties.
In the new study, Chan's lab, with colleagues from India and France, crossed these Arabidopsis plants programmed to eliminate a parent's genes with either of two mutants that can produce diploid eggs.
The result? In about one-third of the seeds produced, the diploid eggs were successfully fertilized, then the chromosomes from one parent were eliminated, leaving a diploid seed that was a clone of one of its parents.
Ravi described the result as a step on the way towards artificial apomixis. The team hopes to produce crop plants, such as lettuce and tomato, that can fertilize themselves and produce clonal seeds. Applications for provisional patents on the work have been filed.
The other authors on the paper are: Mohan Marimuthu, Jayeshkumar Davda and Imran Siddiqi from the Centre for Cellular and Molecular Biology, Hyderabad, India; Sylvie Jolivet, Lucie Pereira, Laurence Cromer, Fabien Nogué and Raphaël Mercier, L'Institut National de la Recherche Agronomique, Versailles, France; and Lili Wang, UC Davis Department of Plant Biology.
The work was principally funded by the National Science Foundation.

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Dandelion dispersing seed. Weeds such as hawkweed and dandelions, can produce true seeds that are clones of themselves without sexual reproduction -- a still poorly understood process called apomixis. (Credit: iStockphoto)

Saturday, February 19, 2011

Astronomers Find a Huge Diamond in Space

Image credit: CfA
When choosing a Valentine’s Day gift for a wife or girlfriend, you can’t go wrong with diamonds. If you really want to impress your favorite lady this Valentine’s Day, get her the galaxy’s largest diamond. But you’d better carry a deep wallet, because this 10 billion trillion trillion carat monster has a cost that’s literally astronomical!

“You would need a jeweler’s loupe the size of the Sun to grade this diamond!” says astronomer Travis Metcalfe (Harvard-Smithsonian Center for Astrophysics), who leads a team of researchers that discovered the giant gem. “Bill Gates and Donald Trump together couldn’t begin to afford it.”

When asked to estimate the value of the cosmic jewel, Ronald Winston, CEO of Harry Winston Inc., indicated that such a large diamond probably would depress the value of the market, stating, “Who knows? It may be a self-deflating prophecy because there is so much of it.” He added, “It is definitely too big to wear!”

The newly discovered cosmic diamond is a chunk of crystallized carbon 50 light-years from the Earth in the constellation Centaurus. (A light-year is the distance light travels in a year, or about 6 trillion miles.) It is 2,500 miles across and weighs 5 million trillion trillion pounds, which translates to approximately 10 billion trillion trillion carats, or a one followed by 34 zeros.

“It’s the mother of all diamonds!” says Metcalfe. “Some people refer to it as ‘Lucy’ in a tribute to the Beatles song ‘Lucy In The Sky With Diamonds.’”

The diamond star completely outclasses the largest diamond on Earth, the 530-carat Star of Africa which resides in the Crown Jewels of England. The Star of Africa was cut from the largest diamond ever found on Earth, a 3,100-carat gem.

The huge cosmic gem (technically known as BPM 37093) is actually a crystallized white dwarf. A white dwarf is the hot core of a star, left over after the star uses up its nuclear fuel and dies. It is made mostly of carbon and is coated by a thin layer of hydrogen and helium gases.

For more than four decades, astronomers have thought that the interiors of white dwarfs crystallized, but obtaining direct evidence became possible only recently.

“The hunt for the crystal core of this white dwarf has been like the search for the Lost Dutchman’s Mine. It was thought to exist for decades, but only now has it been located,” says co-author Michael Montgomery (University of Cambridge).

The white dwarf studied by Metcalfe, Montgomery, and Antonio Kanaan (UFSC Brazil), is not only radiant but also harmonious. It rings like a gigantic gong, undergoing constant pulsations.

“By measuring those pulsations, we were able to study the hidden interior of the white dwarf, just like seismograph measurements of earthquakes allow geologists to study the interior of the Earth. We figured out that the carbon interior of this white dwarf has solidified to form the galaxy’s largest diamond,” says Metcalfe.

Our Sun will become a white dwarf when it dies 5 billion years from now. Some two billion years after that, the Sun’s ember core will crystallize as well, leaving a giant diamond in the center of our solar system.

“Our Sun will become a diamond that truly is forever,” says Metcalfe.

A paper announcing this discovery has been submitted to The Astrophysical Journal Letters for publication.