Mighty Dons Of Science News

NASA Discovers 2 New Planets.

2010-09-02T08:18:00.000-07:00

Two planets slightly smaller than Saturn have been discovered orbiting a distant star, a first for NASA's Kepler space telescope, whose mission is to look for signs of planets passing in front of stars, the space agency said Thursday.

This is "the first discovery of multiple planets orbiting the same star" by looking for such transits, said William Borucki, the science principal investigator for the Kepler Mission. He spoke in a teleconference from the NASA Ames Research Center in California.

The sun-like star, designated Kepler-9, is about 2,000 light years away in the constellation Lyra, he said.

The two planets, named Kepler-9b and 9c, show a clear gravitational interaction, according to NASA. But while scientists hope Kepler will find Earth-like planets, these two do not qualify. In addition to being much larger than Earth, they are much too close to the star they are orbiting.

"The habitable zone is actually quite far out from these stars," Borucki said. These planets "are very, very hot."

Scientists also have identified what appears to be a third, smaller celestial body orbiting the star. It's about 1.5 times the size of Earth, but it has not yet been confirmed as a planet, according to mission scientists. It also is very close to the star, with an orbit of about 1.6 days, NASA said.

The Kepler space telescope launched from Cape Canaveral in March 2009 with the mission of staring at our region of the Milky Way galaxy to search for Earth-size planets that would be in a star's habitable zone.

It is looking at more than 100,000 stars, watching for tiny repeated dips or fluctuations in their brightness. That momentary dimming, scientists say, could indicate a planet has come between the star and the telescope.

Kepler, currently 18 million miles from Earth, will continue its mission for another three and a half years.

In June, NASA announced that the space observatory had identified more than 700 planet candidates in just its first 43 days of searching, including five that could have more than one transiting planet.

"This is like opening a treasure chest," said Matthew Holman of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts.

And scientists say more discoveries are on the way as Kepler and other missions peer into the depths of the Milky Way.

"We want to know, in particular, what [the planets'] atmospheres are like," Borucki said. "Kepler can't tell us that, but missions are on the planning board that may answer those questions, which will help man understand the universe and his place in it."

He added, "A couple of thousand years ago, people asked these questions, and in the Middle Ages, they asked these questions, and now, this is a very exciting period. In the next few years, we'll have the answers to these questions."

Vision gets better with the right mind-set

2010-05-05T06:44:00.001-07:00

Imagine seeing better by thinking differently. That’s a vision with a future, according to Harvard University psychologist Ellen Langer.

Eyesight markedly improved when people were experimentally induced to believe that they could see especially well, Langer and her colleagues report in the April Psychological Science. Such expectations actually enhanced visual clarity, rather than simply making volunteers more alert or motivated to focus on objects, they assert.

Langer’s new findings build on long-standing evidence that visual perception depends not just on relaying information from the eyes to the brain but on experience-based assumptions about what can be seen in particular situations. Those expectations lead people to devote limited attention to familiar scenes and, as a result, to ignore unusual objects and events.

In perhaps the most eye-popping of Langer’s new findings, 20 men and women who saw a reversed eye chart — arranged so that letters became progressively larger further down the chart, with a giant “E” at the bottom — accurately reported more letters from the smallest two lines than they did when shown a traditional eye chart with the big letters on top. All volunteers had normal eyesight.

These results reflect people’s expectation, based on experience with standard eye charts, that letters are easy to see at the top and become increasingly difficult to distinguish on lower lines, the researchers suggest.

Participants who said they thought that they could improve their eyesight with practice displayed a bigger vision boost on the reversed chart than those who didn’t think improvement was possible, but only for the next-to-smallest line. Both groups did equally well at reading the smallest, topmost line.

Another set of experiments included 63 members of the Reserve Officers’ Training Corps at MIT. Eye testing determined that their vision ranged from below average to excellent.

An experimenter told a group of 22 cadets to assume the role of a fighter pilot while operating a flight simulator. During this exercise, participants tried to identify letters shown on four plane wings of approaching aircraft. Each wing contained one of the bottom four lines of an eye chart.

Another 20 cadets performed the visual task while pretending to fly a plane in a simulator that they were told was broken. Ten other cadets read a motivational essay before the exercise. A final group of 11 cadets didn’t use a simulator but practiced eye exercises that researchers described as capable of improving eyesight before taking an eye test.

Vision improved substantially for nine of 22 simulator pilots compared with none of those who pretended to fly, two of 11 eye exercisers and one person in the motivational group. Simulator pilots did so well relative to the others because they more thoroughly adopted a mind-set of being real fighter pilots with presumably superior vision, the researchers posit. An initial survey of ROTC members found that they attributed particularly good vision to fighter pilots.

Simulator pilots with below-average vision displayed the biggest jumps in visual performance, perhaps because they had more room for improvement, the researchers suggest.

These results suggest that if eye exercise programs designed to improve vision work for some people, it’s not because of any physical effect on the eyes or brain. Such regimens “may be effective because they prime the belief that exercise improves vision,” Langer and her colleagues write.

Mind-set may boost visual performance without sharpening vision itself, comments psychologist Daniel Simons of the University of Illinois at Urbana-Champaign. Experimental manipulations in the new study, such as reversing the arrangement of an eye chart, may have made volunteers more willing to guess when they felt a bit unsure, Simons says. Such guesses stand a good chance of being right, in his view.

DNA comparison of identical twins finds no silver bullet for MS

2010-05-05T06:41:00.001-07:00

A new study has come up empty-handed after pursuing a genetic explanation for why one identical twin developed multiple sclerosis while the other stayed healthy.

Researchers transcribed the complete genetic blueprints for a pair of identical twins, looking for differences that might explain why one has multiple sclerosis and the other does not. No trace of what caused the discrepancy appeared in the twins’ DNA. And scientists found no smoking gun when they compared levels of gene activity between the sick and well twin. The results appear in a report published April 29 in Nature.

“We looked under a lot of rocks and we found no differences that we could replicate,” says Stephen Kingsmore, a geneticist at the National Center for Genome Resources in Santa Fe, N.M., and leader of the new study. The finding “points to some novel environmental trigger that must be very important to the disease. We don’t know what it is.”

But the new study is small; it examines only three pairs of twins and one type of immune cell known to be involved in multiple sclerosis. A telling difference between sickness and health might be found in other types of cells, such as immune cells called B cells or in oligodendrocytes, which are cells that make the nerve cell insulation called myelin, says Esteban Ballestar of the Bellvitge Biomedical Research Institute in Barcelona, Spain. “They are closing a door here, but I think, perhaps, the door should be open,” he says.

In multiple sclerosis the immune system attacks and damages the myelin sheath that helps speed electrical communication between nerves, the equivalent of scraping the coating away from an electrical wire. The damage results in pain and symptoms such as loss of coordination and vision.

In the new study, Kingsmore and his colleagues determined the entire genetic makeup of immune cells called T cells from a pair of female twins. One of the women developed multiple sclerosis at age 30 while her twin remained healthy. The twins are now old enough that the healthy one is not likely to develop the disease.

Identical twins share the same genetic makeup, and the researchers confirmed that both women carried variants of genes already known to increase the risk of getting multiple sclerosis. Scientists had thought that maybe the sick twin had developed an additional mutation in her DNA that finally triggered the disease. But the team found no such mutations.

Another way to rev up the immune system and induce it to attack the body is to increase the activity of certain genes. Upping gene activity doesn’t necessarily involve changing the genes themselves, but can be done by altering chemical tags on the DNA. In two pairs of twins, the team examined more than 2 million DNA locations that had been tagged with a common label, known as a methyl group, that keeps gene activity in check.

In a previous study, Ballestar’s group found lower levels of methylated DNA when they compared people with lupus (SN: 1/16/2010, p.13) to their healthy identical twins. But Kingsmore and his colleagues found no similar differences that could account for just one twin developing MS.

The team also measured gene activity in three sets of identical twins, including the sisters who had their genomes sequenced. The researchers did find some minor differences, but none could explain why one twin got sick and the other didn’t.

Scientists bag frog genome

2010-05-05T06:35:00.001-07:00

Frogs have hopped onto the list of organisms that have had their genetic codes unraveled.

A new study, published April 30 in Science, lays out the genetic blueprint of the Western clawed frog, Xenopus tropicalis. A larger cousin of X. tropicalis, called Xenopus laevis, is a popular laboratory organism for studying development. But with a genome about half the size of X. laevis’, the Western clawed frog has easier DNA to decode, says Uffe Hellsten of the Department of Energy Joint Genome Institute in Walnut Creek, Calif.

Analysis of the Western clawed frog’s genome reveals that versions of 80 percent of genes that have been linked to disease in humans turn up in frogs.

Researchers hope that the genome sequence will help scientists track down the molecular steps that lead to amphibians’ high sensitivity to hormones and other toxins and offer clues to what is causing a worldwide decline of the animals.

Genetic changes show up in people with PTSD , But it's unclear if alterations cause the disorder

2010-05-05T06:32:00.000-07:00

People with post-traumatic stress disorder seem to accumulate an array of genetic changes different from those found in healthy people, researchers report online May 3 in the Proceedings of the National Academy of Sciences.

The new findings, while showing differences between people with and without PTSD, don't shed light on whether these differences might play a role in PTSD, says study coauthor Sandro Galea, a physician and epidemiologist at Columbia University in New York City.

Only a fraction of people who witness a traumatic event develop PTSD. In an attempt to identify what makes people who develop PTSD biologically different from those who don’t, Galea and his colleagues obtained blood samples from 100 people in the Detroit area. All had been exposed to at least one potentially traumatic event, and 23 were diagnosed with PTSD. The scientists tested 14,000 genes in these blood samples for chemical changes to DNA that can affect gene activity without altering the genetic information itself.

The researchers focused on the methylation of genes, a process in which a methyl molecule is added to DNA, typically turning off a gene and inhibiting production of the protein that the gene encodes. If people with PTSD have more or less methylation in specific genes, that might somehow contribute to PTSD, Galea says.

The team found that the people with PTSD showed less methylation in several immune system genes and more methylation in genes linked to the growth of brain cells. “There is evidence that PTSD is involved in immune dysfunction, and we suggest that that’s part of a larger process,” Galea says. Although previous studies have also suggested a PTSD link to immune gene activation, the connection is unclear.

“This is interesting data, but there are a lot of things still to do,” says Manel Esteller, a molecular geneticist at the Bellvitge Institute for Biomedical Research in Spain and the University of Barcelona who was not part of the study. “What’s missing is an explanation of how the traumatic stress really causes these changes in methylation — what is the mechanistic link?”

What’s more, the sample size of 23 patients is small, and PTSD diagnosis is tricky, says Naomi Breslau, a sociologist and epidemiologist who studies PTSD at Michigan State University in East Lansing. “I don’t believe this can be taken as a breakthrough.”

Galea agrees that finding the mechanisms involved will be the key to determining whether these methylation differences matter for PTSD. If further research clarifies how these changes play out in the body, he says, “that may allow us to eventually do something about it.”

Possible new extinct human species identified

2010-03-31T19:39:00.000-07:00

A previously unknown lineage of humans has been identified based on genes extracted from a bit of bone found in Siberia, scientists say.

The finding may represent a new species that lived alongside Neanderthal people and anatomically “modern” humans in that region, according to the researchers.

“I at first didn’t believe” that the result could be possible, said one of the researchers involved with the finding, Svante Pääbo of the Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany. However, Pääbo said, genetic test results showed “it’s some new creature that has not been on our radar screen so far.” The findings are published in the March 25 issue of the research journal Nature.

The conclusions were based on the sequencing, or decoding, of the organism’s “mitochondrial genome,” that is, DNA from a cellular structures called the mitochondria.

Mitochonchondrial DNA is not inherited the same way as the rest of an animal’s DNA, but rather is passed down only from the mother. Because unlike other DNA it remains relatively unchanged when passed down through generations, it plays an important role in ancestry studies, in particular in determining an organism’s mother-line ancestry.

The genetic sequencing pointed to a previously unknown hominin, or extinct member of the human lineage, who lived in the Altai mountains of southern Siberia between 48,000 and 30,000 years ago, said the researchers.

The investigating team, which included also researchers from the United States, Austria and Russia, sequenced genes from a tiny piece of pinky finger bone found in Denisova cave in the Altai Mountains. They compared the mitochondrial genome with that of modern humans and Neanderthals.

The analysis indicated that the creature shared a common female or “mitochondrial” ancestor with modern human and Neanderthals about a million years ago, the scientists said. That’s about twice as old as what is believed to be the most recent common mitochondrial ancestor of modern humans and Neanderthals. Neanderthals were a stocky, now extinct subgroup of our species, Homo sapiens, who lived in Europe and parts of Asia from around 100,000 to 30,000 years ago.

The age of the fossil and the layers of earth in which they turned up also suggest “the Denisova hominin lived close in time and space with Neanderthals as well as with modern humans,” the researchers wrote.

Although researchers said they lacked definitive enough information to declare the fossil a new species, they said it also likely represented a separate migration out of Africa from modern humans and Neanderthals, both of whom are thought to have originated in that continent. The investigators also said they have no information yet that could serve to physically describe any unusual characteristics that the newfound human ancestor might have possessed.

New anti-cancer strategy: make tumor cells age

2010-03-31T19:11:00.000-07:00

Researchers have identified a chemical chain of events that leads cancer cells to age, and thus stop reproducing. By exploiting this process, they propose, scientists might be able to develop new cancer therapies.

The molecular sequence of events, called a signaling pathway, is described in the March 18 issue of the research journal Nature by investigators Paolo Pandolfi of the Harvard Medical School and colleagues.

Cancer cells are normally able to reproduce themselves indefinitely without ageing; this indeed is a core aspect of the problem confronting cancer victims. The out-of-control cell division leads to the creation of an ever-growing load of tumors.

The newfound pathway drives cell aging, or “senescence,” only in cancerous conditions, according to Pandolfi’s group. A key component of the pathway is a gene called Skp2, the scientists reported. By suppressing this gene, they found that they could profoundly restrict tumor formation in mice by causing cancer cells to age. The process curbed cell division.

The researchers also found that a Skp2-blocking drug induced aging in a laboratory culture of human prostate cancer cells.

Because the newfound aging pathway seems to operate only in cancer, it raises hopes that it could prove a useful target for anti-cancer treatments, which might avoid harming healthy cells, the researchers argued. Such a treatment might also have the advantage of operating in a wide array of different cancer types.

“The challenge ahead is to test whether these preclinical studies in mice can be translated into more effective cancer therapies,” wrote Manuel Serrano is of the Spanish National Cancer Research Centre in Madrid, in a commentary accompanying the study in Nature.

Psychopaths’ brains wired to seek rewards no matter what, scientist say.

2010-03-31T19:01:00.000-07:00

A study has now found that the brains of psychopaths seem to be wired to keep seeking a reward at any cost. Scientists say the research clarifies the role of the brain’s reward system in psychopathy and opens a new area of study for understanding what drives these twisted minds.

The study from from Vanderbilt University in Nashville, Tenn. is published in the March 14 issue of the research journal Nature Neuroscience.

“Psychopaths are often thought of as cold-blooded criminals who take what they want without thinking about consequences,” Joshua Buckholtz, a graduate student in psychology and lead author of the new study, said. “We found that a hyper-reactive dopamine reward system may be the foundation for some of the most problematic behaviors associated with psychopathy, such as violent crime, recidivism and substance abuse.”

Dopamine is the brain chemical most closely associated with pleasure and excitement.

Previous research on psychopathy has focused on what these people lack—fear, empathy and interpersonal skills. The new research, however, examines what they have in abundance—impulsivity, heightened attraction to rewards and risk taking, said Buckholtz and his co-authors. Importantly, the latter traits are those most closely linked with the violent and criminal aspects of psychopathy, researchers said.

“There has been a long tradition of research on psychopathy that has focused on the lack of sensitivity to punishment and a lack of fear, but those traits are not particularly good predictors of violence or criminal behavior,” said Vanderbilt psychologist David Zald, co-author of the study.

“Our data is suggesting that something might be happening on the other side of things. These individuals appear to have such a strong draw to reward—to the carrot—that it overwhelms the sense of risk or concern about the stick.”

The researchers used a brain imaging technique called positron emission tomography, or PET, to measure dopamine release, in concert with a probe of the brain’s reward system using functional magnetic imaging, or fMRI. “The really striking thing is with these two very different techniques we saw a very similar pattern—both were heightened in individuals with psychopathic traits,” Zald said.

Volunteers for the study took a personality test to gauge their level of psychopathic traits. These traits lie on a spectrum: violent criminals fall at its extreme end, but a normally functioning person can also have psychopathic traits to some degree. These traits include manipulativeness, egocentricity, aggression and risk taking.

The researchers gave the volunteers a dose of amphetamine, or speed, and then scanned their brains using PET to view dopamine release in response to the stimulant. Substance abuse has been shown in the past to be associated with alterations in dopamine responses. Psychopathy is strongly associated with substance abuse.

“Our hypothesis was that psychopathic traits are also linked to dysfunction in dopamine reward circuitry,” Buckholtz said. “Consistent with what we thought, we found people with high levels of psychopathic traits had almost four times the amount of dopamine released in response to amphetamine.”

The research subjects were later told they would receive some money for completing a simple task. Their brains were scanned with fMRI while they were performing the task. The researchers found in those participants with more psychopathic traits the dopamine reward area of the brain, the nucleus accumbens, was much more active while they were anticipating the reward.

“It may be that because of these exaggerated dopamine responses, once they focus on the chance to get a reward, psychopaths are unable to alter their attention until they get what they’re after,” Buckholtz said. Added Zald, “It’s not just that they don’t appreciate the potential threat, but that the anticipation or motivation for reward overwhelms those concerns.”

Distant solar system forming from mysterious dust, scientists say

2010-01-16T04:54:00.000-08:00

Artist'srendering of what HD 131488's inner planetary system might look like as two large rocky bodies collide. Inset illustrates the location of HD 131488's dust belts (top) and comparable regions to our own Solar System (bottom). HD 131488's hot inner dust belt has similar separations from its host star as the terrestrial planet zone around our Sun while the star's cool dust belt has similar separations from its host star as the Kuiper Belt region in our Solar System. Also shown for our Solar System are the orbits of Jupiter, Saturn, Uranus, and Neptune.</font> (Courtesy Gemini Observatory)

A far-off solar system seems to be forming from a strange dust whose makeup is unlike that of our and other solar systems, astronomers say.

The researchers at the University of California Los Angeles found evidence for the formation of young, rocky planets from dust circling a star some 500 light-years away. A light-year is the distance light travels in a year

“Until now, warm dust found around other stars has been very similar in composition to asteroidal or cometary material in our Solar System,” said the university’s Carl Melis, who led the research while a graduate student.

But this case is different, he said.

“Typically, dust debris around other stars, or our own Sun, is of the olivine, pyroxene, or silica variety, minerals commonly found on Earth,” he noted. But this material “is not one of these dust types. We have yet to identify what species it is.”

Melis reported the findings last Wednesday at the annual American Astronomical Society meeting in Washington, D.C.

The star, known as HD 131488, appears to be surrounded by warm dust in a region called the terrestrial planet zone, where temperatures are similar to those on Earth, Melis said. He added that the dust seems to harbor rocky, embryonic planets that have recently collided.

“What makes HD 131488 truly unique is the unidentified dust species released from the colliding bodies as well as the presence of cold dust far away from the star,” said astronomer Benjamin Zuckerman of the university, a co-author of the research. “These two characteristics make HD 131488 unlike any other star with evidence for massive quantities of dust in its terrestrial planet zone.”

The researchers analyzed the warm inner dust through infrared imaging and spectroscopy using an instrument called T-ReCS on the Gemini South telescope in Chile. Spectroscopy is the analysis of the composition of objects using the spectrum of light they give off.

Melis and his team argue that the most plausible explanation for the unusual abundance of warm dust is a recent collision of two rocky planetary mass bodies.

While the mysterious warm dust lies at a distance from HD 131488 that is comparable to the Earth-Sun separation, the team also found cooler dust about 45 times further out. This outer dusty region is analogous to the Kuiper Belt in our own Solar System where many minor planets orbit the Sun just beyond the orbit of Neptune.

“The hot dust almost certainly came from a recent catastrophic collision between two large rocky bodies in HD 131488’s inner planetary system,” Melis said. But the cooler dust “is probably left over from planet formation that took place farther away from HD 131488.”

HD 131488 lies in the direction of the constellation Centaurus and is three times heavier and 33 times more luminous than our own Sun. The star is part of a major, southern-hemisphere star forming region known as the Upper-Centaurus-Lupus association whose members are believed to be about 10 million years old. By contrast, the Sun and Earth are about 4.6 billion years old..

Females may harbor biological “inner male”

2010-01-12T09:06:00.000-08:00

In adult female mice, switching off one gene seems to start turning the ovaries into testicles and triggers the production of male hormones at normal male levels, scientists say.

The curious findings have led two researchers to remark in a published paper that, biologically speaking, females may be engaged in a lifelong “battle to suppress their inner male.”

Both papers appear in the Dec. 11 issue of the research journal Cell.

The new results echo a previous study that found that female ovarian tissues in mice start to convert to male-like tissues in the absence of signals from estrogen, a female sex hormone. That study appeared in the Dec. 17, 1999 issue of the journal Science.

In the newer research, N. Henriette Uhlenhaut of the European Molecular Biology Laboratory in Heidelberg, Germany, and colleagues were studying genes that during development are responsible for converting glands called gonads into either ovaries or testicles, depending on the sex.

Ovaries produce eggs, the female sex cells, while testicles produce sperm.

Uhlenhaut and colleagues genetically engineered mice in which the activity of a called Fox2L could be chemically suppressed in the ovaries.

Fox2L, in turn, is a regulator gene that influences the level of activity of an array of other genes. Among other things, it keeps in check genes that tend to promote testicle development, according to Uhlenhaut’s group.

Switching off Fox2L had the immediate effect of increasing the level of activity of some of these “testis-specific” genes, the scientists reported. Critical among these, they identified one called Sox9.

Concomitant with the boost in Sox9 activity was a “reprogramming” of certain ovarian cell lineages into what appeared to be testis cell lineages, Uhlenhaut and colleagues found. Meanwhile, the modified ovaries began producing normal male-like levels of the hormone testosterone.

“Our results show that maintenance of the ovarian phenotype [form] is an active process throughout life,” the scientists wrote.

It’s unclear whether the findings would translate to humans, but because mice share over 90 percent of their genes with humans, it very often happens that mouse processes have parallels in humans.

It would seem “testicular development is actively repressed throughout the life of females,” added Andrew Sinclair and Craig Smith of the Murdoch Children’s Research Institute in Melbourne, Australia, in a paper published in the same issue of Cell. Sinclair and Smith the researchers who in their article metaphorically suggested an “inner male” may lurk within all females also noted the findings go against “conventional wisdom” that the ovary and testis are “terminally differentiated,” or irreversibly developed to their mature state.

“Lifeless” molecules found to evolve, adapt

2010-01-12T08:55:00.001-08:00

Scientists have found that prions infectious molecules that cause fatal brain diseases can evolve in a Darwinian fashion, though they lack any DNA or similar material.

The study from Scripps Research Institute in Jupiter, Fla. found that prions can develop many mutations. Mutations that help the prions to withstand threats then tend to persist in a “population” of prions, while other prions are destroyed. This eventually leads the prions to develop adaptations such as drug resistance.

The process in other words would seem to be analogous to the way that living things evolve, according to Darwinist principles. Viruses, too which are often considered non-living can evolve. But unlike prions, viruses have in common with life forms that they contain DNA or closely related molecule, RNA.

The prion study was published in the Dec. 31 issue of the research journal Science Express, an advance, online edition of the journal Science.

Prions consist of proteins, large molecule composed of many smaller molecular subunits of so-called amino acids. Protein molecules have different characteristics depending on the precise arrangement of their subunits. This includes different ways the protein’s parts can be folded about with respect to each other.

Many of the prion “mutations” boil down to different folding arrangements, said Charles Weissmann, head of Scripps Florida’s Department of Infectology, who led the study. These various foldings play an analogous evolutionary role in prions to different DNA sequences, or codes, in the evolution of living things.

“On the face of it, you have exactly the same process of mutation and adaptive change in prions as you see in viruses,” he explained.

Infectious prions short for proteinaceous infectious particles are associated with some 20 different diseases in humans and animals, including mad cow disease and a rare human form, Creutzfeldt-Jakob disease. All are untreatable and eventually fatal. Prions, which are composed solely of protein, are classified by distinct strains, originally characterized by their incubation time and the disease they cause.

Prions exist in a normal, healthy form, produced naturally in mammalian cells, called cellular prion protein or PrPC. The disease process begins when prions take on an abnormal, misfolded form. A normal prion that comes into contact with a misfolded one may as a result become misfolded itself. This zombie-like process may eventually lead to the creation of huge assemblies of these misfolded proteins. They stick together and cause massive damage.

“It was generally thought that once cellular prion protein was converted into the abnormal form, there was no further change,” Weissmann said. “But there have been hints that something was happening. When you transmit prions from sheep to mice, they become more virulent over time. Now we know that the abnormal prions replicate, and create variants, perhaps at a low level initially. But once they are transferred to a new host, natural selection will eventually choose the more virulent and aggressive variants.”

Weissmann and his colleagues transferred prion populations from infected brain cells to culture cells. When transplanted, cell-adapted prions developed and out-competed their brain-adapted counterparts, confirming prions’ ability to adapt to new surroundings, according to the scientists. When returned to brain, brain-adapted prions again took over the population.

Weissmann said the findings have implications for the development of treatments. Instead of developing drugs to target abnormal proteins, it could be more efficient to try to limit the supply of normally produced prions – in essence, reducing the amount of fuel for the fire, he proposed. Weissmann and his colleagues found some 15 years ago that genetically engineered mice devoid of the normal prion protein develop and function quite normally and are resistant to prion disease.

“Finding a way to inhibit the production of normal prion protein is a project currently being pursued in collaboration with Scripps Florida Professor Corinne Lasmezas in our department,” he said.

Baby temperament found to predict adult brain structure

2010-01-12T08:25:00.001-08:00

In a study that could help clarify the complex relationships between the brain, environment and behavior, researchers have found that four-month-old infants’ temperament predicts some aspects of their brain structure 18 years later.

Scientists at Massachusetts General Hospital in Charlestown, Mass., studied 76 eighteen-year-olds that, at four months of age, had been categorized in previous research as “high-reactive” or “low-reactive.” High-reactive generally means shy and inhibited, while low-reactive means outgoing and uninhibited.

The investigators used a form of brain scanning known as structural magnetic resonance imaging, which employs magnetic field and radio waves to produce clear and detailed pictures of the brain.

Adults with a low-reactive infant temperament showed greater thickness in a brain structure called the left orbitofrontal cortex, the scientists found. This region has been implicated in processing of emotions and of self-monitoring.

On the other hand, the adults previously categorized as high-reactive, showed greater thickness in the right ventromedial prefrontal cortex, the researchers reported. This brain area has been linked to impulse control, with greater size linked to more self-control, and with the analysis of social situations.

“To our knowledge, this is the first demonstration that temperamental differences measured at four months of age have implications for the architecture of human cerebral cortex lasting into adulthood,” the researchers wrote in the study, published in the January issue of the journal Archives of General Psychiatry. The cerebral cortex is a layer of brain cells covering the surface of the brain and linked to advanced thinking functions.

High-reactive infants are characterized at age four months by vigorous activity and crying in response to unfamiliar stimuli, according to the authors, Carl Schwartz, director of the hospital’s Developmental Neuroimaging and Psychopathol&sh Research Laboratory, and colleagues. Low-reactive infants by contrast stay more still and cry less in respose to the same situations.

High-reactive infants tend to become behaviorally inhibited in the second year of life, while low-reactive infants tend the opposite way, the authors added.

First “super-Earths” found orbiting sun-like stars

2009-12-22T07:22:00.000-08:00

Astronomers have reported finding as many as six planets, not many times heavier than Earth, orbiting two nearby Sun-like stars.
The objects, which include two that are about 5 and 7.5 times as heavy as Earth, are raising scientists’ hopes that it will be just a few years that planets very much like ours turn up.

Image from a scientists' animation of the 5-Earth-mass planet 61 Vir B, orbiting the star 61 Virginis. This planet moves in a tight, 4-day orbit around its star. Half of the planet surface is much hotter than the other half because one side always faces the star. (Courtesy U. Hertfordshire)

The researchers, led by Steven Vogt of the University of California, Santa Cruz, and Paul Butler of the Carnegie Institution of Washington, said the two “super-Earths” are the first ones found around Sun-like stars.

“These detections indicate that low-mass planets are quite common around nearby stars. The discovery of potentially habitable nearby worlds may be just a few years away,” said Vogt. Astronomers claim they’re overcoming past difficulties in finding smaller planets, which are more like ours in size and are considered likelier to be habitable than large planets.

The team found the new planet systems by combining data gathered at the W. M. Keck Observatory in Hawaii and the Anglo-Australia Telescope in New South Wales, Australia. Two papers describing the new planets have been accepted for publication in the Astrophysical Journal.

Three of the new planets orbit the bright star 61 Virginis, visible with the naked eye under dark skies in the Spring constellation Virgo. Space scientists have long been fascinated with this star, which is a relatively close 28 light years away (a light year is the distance light travels in a year). Among hundreds of our nearest stellar neighbors, 61 Vir stands out as being the most nearly similar to the Sun in terms of age, mass, and other essential properties.

Vogt and colleagues have found that 61 Vir hosts at least three planets, weighing in the range of about 5 to 25 Earths. All would be extremely hot, though, as they are well within orbits equivalent to that of Venus.

Recently, a separate team of astronomers used NASA’s Spitzer Space Telescope to discover that 61 Vir also contains a thick ring of dust at a distance roughly twice as far from 61 Vir as Pluto is from our Sun. The dust is apparently created by collisions of comet-like bodies in the cold outer reaches of the system.

“Spitzer’s detection of cold dust orbiting 61 Vir indicates that there’s a real kinship between the Sun and 61 Vir,” said Eugenio Rivera of the University of California, Santa Cruz. Rivera computed an extensive set of simulations to find that a habitable Earth-like world could easily exist in the as-yet unexplored region between the newly discovered planets and the outer dust disk.

According to Vogt, the planetary system around 61 Vir is an excellent candidate for study by the new Automated Planet Finder Telescope recently constructed at Lick Observatory on Mount Hamilton near San Jose, Calif. “Needless to say, we’re very excited to continue monitoring this system” using that device, said Vogt, who is the principal investigator for the telescope.

The second new system found by the team features a planet weighing the equivalent of about 7.5 Earths and orbiting the star HD 1461, another near perfect twin of the Sun about 76 light-years away. The planet, designated HD 1461b, is about halfway between Earth and Uranus in weight. The researchers said they cannot tell yet if it’s a scaled-up version of Earth, composed largely of rock and iron, or whether, like Uranus and Neptune, it is made mostly of water.

At least one and possibly two additional planets also orbit the star, the group said. Lying in the constellation Cetus, HD 1461 can be seen with the naked eye in the early evening under good dark-sky conditions.

The Lick Carnegie Exoplanet Survey Team led by Vogt and Butler uses velocity measurements from ground-based telescopes to detect the “wobble” induced in a star by the gravitational tug of an orbiting planet. In the past year, improving methods have made it evident that planets orbiting the Sun’s nearest neighbors are extremely common: current indications are that fully half of nearby stars have a detectable planet with mass equal to or less than Neptune’s, Butler said.

The Lick-Carnegie Exoplanet Survey Team has developed a publicly available tool, the Systemic Console, which enables members of the public to search for the signals of extrasolar planets by exploring real data sets. This tool is available online at www.oklo.org.

Poor, misunderstood testosterone

2009-12-22T06:57:00.001-08:00

Despite popular conceptions about the hormone testosterone, in women, at least, the substance actually may promote fair, conciliatory behavior, researchers say.

But the myths about testosterone are so powerful that women in a study started acting less fairly if they thought they had received a dose of it, whether they had or not.

Such are the findings of a study appearing in the Dec. 8 advance online issue of the research journal Nature.

Testosterone is often called the “male” hormone and is popularly associated with aggression. Women have some testosterone also, though.

Ernst Fehr of the University of Zurich, Switzerland, and colleagues set up a bargaining game in which female participants were given a pill either of testosterone or of a neutral substance, called a placebo.

Those that received testosterone showed a “substantial increase in fair bargaining behaviour,” leading to better social interactions, the researchers wrote. But women who thought that they received testosterone, whether or not they actually did, “behaved much more unfairly” than those who thought that they received placebo.

So, the negative, antisocial connotation of increasing testosterone levels seems to be strong enough to induce negative social behaviour even when the biological result is actually the opposite, the scientists remarked.

Evidence from animal studies does show that testosterone causes aggression toward other members of the species, Fehr and colleagues wrote. Popular wisdom tends to assume humans work the same way. But it has been unclear whether this is correct.

Studies have indeed found that male and female prisoners with violent histories have higher salivary testosterone levels than nonviolent prisoners, the researchers noted. But this does not show that the testosterone actually caused the violence.

A competing idea, they observed, is that testosterone motivates people to seek high social status. Depending on the situation, they may try to achieve that either through violence or through fairness.

In the context of the experimental bargaining game, fairness tended to help protect social status, according to Fehr and colleagues.

In the “ultimatum game,” as it was called, two players are presented with a sum of money, which they can keep if they can agree on how to split it. The catch is that just one player gets to propose—and only once—how it should be divided. The other player must accept or reject that offer. “Fair” offers, such as an even split, tend to be more readily accepted than “unfair” offers where the proposer tries to keep most of the money. Fehr and colleagues suggested that testosterone motivated players to propose “fairer” offers in order to avoid the social affront of rejection.

Mice Holding Back Muscular Dystrophy Research?

2009-12-04T02:44:00.001-08:00

Humans and mice have previously unknown and potentially critical differences in one of the genes responsible for Duchenne muscular dystrophy (DMD). Researchers writing in the open access journal BMC Biology have found that two major features of a key DMD gene are present in most mammals, including humans, but are specifically absent in mice and rats, calling into question the use of the mouse as the principal model animal for studying DMD.

Roland Roberts led a team of researchers from King's College London, UK, and was funded by the Muscular Dystrophy Campaign. The team made the discovery while studying α-dystrobrevin, a component of the dystrophin protein complex that is disordered in DMD. Roberts said, "Two previously unrecognized features (a gene switch or promoter and a novel binding site for the adaptor protein syntrophin) are encoded by the α-dystrobrevin gene of almost all four-legged animals except mice. We assume that this tardy recognition of key features of a gene that has been intensively studied since its discovery 13 years ago is due to the predominance of the mouse as the model organism for studying DMD and the specific destruction of these parts of the gene in the mouse."

A major consequence of these findings is that mice (and their rat and hamster relatives) are likely to be particularly poor models in which to study the effects of DMD on the brain. Roberts added, "The brain is the major site of α-dystrobrevin expression and we now know that the mouse is missing more than 50% of the brain α-dystrobrevins. The fact that there are fundamental differences between the brains of mice and humans potentially limits our understanding of the role of dystrobrevins and DMD-related complexes in this organ. In fact, almost all of our knowledge of the function of α-dystrobrevin has been gleaned from the mouse."

DMD is a fatal skeletal myopathy, causing loss of muscle tissue throughout the body. It is also associated with substantial neurological effects including learning difficulties, night blindness, defective color vision and a suggestion of personality disorders, so studying the mechanisms in the brain underlying these effects is crucial.

Newly Discovered Fat Molecule: An Undersea Killer With An Upside

2009-12-04T02:40:00.000-08:00

A chemical culprit responsible for the rapid, mysterious death of phytoplankton in the North Atlantic Ocean has been found by collaborating scientists at Rutgers University and the Woods Hole Oceanographic Institution (WHOI). This same chemical may hold unexpected promise in cancer research.
A photomicrograph of an Emiliania huxleyi cell. The black spots within the cell are the virus, which contains a previously unknown lipid that is killing phytoplankton in the North Atlantic. (Credit: V. Starovoytov and A. Vardi, Rutgers University)

The team discovered a previously unknown lipid, or fatty compound, in a virus that has been attacking and killing Emiliania huxleyi, a phytoplankton that plays a major role in the global carbon cycle.

"Emiliania huxleyi is the rock star of phytoplankton," explains Kay Bidle, Rutgers assistant professor of marine science in the Institute of Marine and Coastal Sciences. "It blooms all over the oceans, and we can easily see it by satellite. We know that these blooms are frequently infected with viruses, and this virus is specific to this phytoplankton."

"The lipids are the key ingredient in the virus that causes the phytoplankton to die," says WHOI scientist Benjamin Van Mooy. "We have a completely different lipid molecule that, as far as we know, is unknown to science."

E. huxleyi grows rapidly in the North Atlantic, "in these big blooms that you can actually see from outer space," Van Mooy says.

"But," adds Van Mooy, "they die just almost as quickly as they start out, and we're not sure why. They die after a few days."

Bidle and Assaf Vardi, a postdoctoral investigator in his laboratory and the study's lead author, had been examining the interaction between the virus and the dying phytoplankton and had developed ideas for how this process works. After Vardi heard lipid expert Van Mooy give a talk in Santa Fe, N.M., he suggested the collaboration between WHOI and Rutgers.

"I saw Ben's talk on marine microbes and lipids…[and] I ran after him," said Vardi. "We told him about our ideas" involving the virus's effect on the phytoplankton.

"They studied the viruses and I study lipids," Van Mooy said. "It seemed like a good mix."

Their paper is published in the Nov. 6 issue of Science., E. huxleyi performs photosynthesis -- "just like plants," says Van Mooy. "They suck up carbon dioxide." In doing so, they reduce the amount of CO2 released into the atmosphere. They form a calcium carbonate shell, also helping to regulate the carbon cycle.

If viruses are killing off phytoplankton, this can increase greenhouse emissions, Van Mooy suggests. "That's important because if viruses infect a whole bunch of cells, then they can't perform photosynthesis, they can't take up carbon dioxide."

In April 2008, Van Mooy's team visited the sites of E. huxleyi blooms during a research cruise between Woods Hole and Bermuda and collected samples for lipid analysis back in the laboratory.

They immediately recognized lipids that were just like those in virally infected E. huxleyi cells grown by the Rutgers team. Helen Fredricks, a research associate with Van Mooy, carried out the lipid analyses at WHOI. "Seeing this viral lipid appear during the course of infection was amazing, and then we found it in the ocean too. We were celebrating in the lab that day."

Adds Vardi: "Viruses are really important players in regulating phytoplankton blooms. We zoom into the bloom and try to understand the interaction between the viruses and host, which is this really important, cosmopolitan, bloom-forming species."

After isolating the viral lipids, the team found that the lipids alone were able to bring about the symptoms of viral infection in the phytoplankton. "The lipids themselves act just like the virus," says Van Mooy. "We can cause the phytoplankton to die by just giving the lipids."

This alone was enough to excite the team. "Now we have a biological marker that we can go out on a ship and look for and identify where this [infection of phytoplankton] is happening and learn how to study it better," Van Mooy says.

But there may be other, even farther-reaching implications. Both the virus and the newly found lipid deal their deadly blow by causing the upper-ocean plants to commit cellular suicide. As a major focus of their research at Rutgers, Bidle's lab has found that "programmed cell death" is an important process in the fate of marine phytoplankton and in the demise of blooms in the oceans. Bidle's group had previously found that successful infection of E. huxleyi induced, and actually required, the programmed cell death pathway.

But programmed cell death is not unique to phytoplankton. It is a common and healthy process in all kinds of cells, including human cells.

According to Vardi, "These lipids can induce programmed cell death in many organisms, including animals and plants. They also enrich in plasma membrane, and they are the port of the cell, where pathogens get in and out of the cell. This is important in viral diseases."

There is also a potential connection with cancer. If a healthy cell is stressed or damaged, usually it will kill itself with programmed cell death. But cancer cells have a defect: "They don't kill themselves," says Bidle.

"It's a critical aspect of cancer research, because cancer cells have figured out a way to turn off the programmed cell death pathway," he says. "In cancer studies, they try to figure out ways to reactivate those pathways."

The lipid may help shed light on why cancer cells are unable to commit suicide. Someday, the researchers say, it might suggest ways to correct that defect. Right now, the lipid is only known to be effective in algae, but in the future, the team is hoping to test the effectiveness of their molecule in experiments with cancer cells.

"There's a long way to go between here and curing cancer," Van Mooy says, "but the potential exists that this molecule could have therapeutic applications in the treatment of human disease, including cancer. Hopefully this paper will pique the interest of other investigators."

More immediately, scientists hope to learn more about the central role phytoplankton -- and viruses -- play in regulating climate. Bidle says this is a particularly interesting virus. "It appears that the virus has…borrowed, copied actually, the genes for this lipid from the host," he says. "Similar genes are still on the host, but the virus has figured out a way to take those genes and put them into its own genome, and alter them enough to make them more toxic."

"We find the biosynthetic pathway for this unique lipid encoded in the virus genome, not only in the host, and this has never been described before in any other virus," Vardi says. "We knew that [lipids] were important, but we were really intrigued about why the virus contained these genes. And what is the role of the pathway in the co-evolution of programmed cell death in the host and virus."

Van Mooy sees it as a struggle between two mighty forces. "The phytoplankton are at one end of the boxing ring and they're taking up carbon dioxide, and the viruses are at the other end, and they're out to kill them. And how that works out controls how much carbon dioxide is taken up.

"We're very interested in understanding what controls these phytoplankton," he says. "I didn't know that much about viruses until I started working on this project and the Rutgers researchers didn't know that much about lipids. So now we're both really onto something here. We're continuing to collaborate. "We have found other interesting lipids from these viruses," says Van Mooy.

"There are probably more out there. And who knows what kind of activities they may be involved with. They may hold a cure for a human disease or they may play unknown role in…phytoplankton.

New Tool in Fight Against Autoimmune Diseases, Blood Cancers

2009-12-04T02:35:00.000-08:00

Scripps Research Institute scientist describes a new, highly pragmatic approach to the identification of molecules that prevent a specific type of immune cells from attacking their host. The findings add a powerful new tool to the ongoing search for potential treatments for autoimmune diseases, such as multiple sclerosis (MS), as well as blood cancers, such as myeloid leukemia.

The study by Thomas Kodadek, a professor in the Chemistry and Cancer Biology Departments at Scripps Florida, and colleagues was published in the journal Chemistry & Biology.

In the new study, Kodadek and his colleagues used samples from an animal model of multiple sclerosis to screen for T cells -- a type of white blood cell that plays a central role in the immune system -- with a heightened presence in the disease. The screen also identified molecules that interfere with these T cells' "autoreactivity," in other words, their attack on the body itself rather than a foreign invader such as virus or bacteria.

"Our technique simultaneously uncovers and isolates autoreactive T cells as well as inhibitors to them," Kodadek said. "It's a double whammy. At the heart of this is a comparative screening process of normal T cells versus disease-causing T cells. While the process is technically complicated and difficult, the thinking behind it is not. We wanted to simplify the process of identifying compounds that could inhibit autoreactive T cells with exceptional specificity, and we succeeded."

The scientists used a model of MS, an autoimmune inflammatory disease affecting the brain and spinal cord, for the study. In MS, the immune system attacks the myelin sheath covering and protecting nerve cells, leading to a variety of symptoms depending on which part of the nervous system is affected. Common symptoms of the condition include fatigue; numbness; walking, balance, and coordination problems; bladder and bowel dysfunction; vision problems; dizziness and vertigo; sexual dysfunction; pain; cognitive problems; emotional changes; and spasticity.

Simplifying the Process

In setting up the new method to shed light on such autoimmune diseases and other disorders, Kodadek and his colleagues created a large collection of peptoids -- molecules related to, but more stable than, the peptides that make up proteins. By arranging thousands of peptoids on a microscope slide, the pattern of binding antibodies (a type of immune molecule) and peptoids can be visualized. By looking at samples from animal models of a known disease like MS, peptoids that bind to antibodies closely associated with that disease can be easily recognized.

Better still, peptoids that bind to autoreactive T cells can be identified without knowledge of the specific antigen (molecule triggering the immune attack), providing an unbiased method with which to search for potentially useful compounds.

Most autoimmune research has focused on finding the disease-causing antigens first, Kodadek said, a Quixote-like quest that has lasted more than four decades with little success to show for it.

"With our process, it doesn't really matter what the antigen is," said Kodadek, a 2006 recipient of the National Institutes of Health Director's Pioneer Award, which is designed to support individual scientists of exceptional creativity. "That was really the breakthrough. We're setting up a system that recognizes T cell receptors that are very abundant in a sick animal and at low levels in a healthy animal. Why the abundance? Because that's what making them sick."

Potential for Therapeutic Discovery

The new process creates new potential for therapeutic discovery. Molecules that target autoreactive T cells directly, while ignoring those T cells that recognize foreign antigens, could serve as the foundation for a novel drug development program aimed at eradicating autoreactive cells without affecting the normal function of the immune system.

"Almost without exception, drugs currently used to treat autoimmune conditions either inhibit something downstream of the autoimmune response itself, like inflammation, or they moderate the immune system non-selectively and that results in significant side effects," Kodadek said.

However, the new study isn't the final answer, according to Kodadek. He noted that the recent study used a model of MS triggered by a single antigen. In humans, there could be two -- or two dozen -- antigens triggering an autoimmune disease such as MS. This calls for further research. The method may be more easily applied to blood cancers, though, since the disease-causing T cells have been fully characterized and there are very few of them.

First Direct Observation of a Planet-Like Object Orbiting Star Similar to Sun

2009-12-04T02:23:00.000-08:00

An international team of scientists that includes an astronomer from Princeton University has made the first direct observation of a planet-like object orbiting a star similar to the sun.

The finding marks the first discovery made with the world's newest planet-hunting instrument on the Hawaii-based Subaru Telescope and is the first fruit of a novel research collaboration announced by the University in January.

The object, known as GJ 758 B, could be either a large planet or a "failed star," also known as a brown dwarf. The faint companion to the sun-like star GJ 758 is estimated to be 10 to 40 times as massive as Jupiter and is a "near neighbor" in our Milky Way galaxy, hovering a mere 300 trillion miles from Earth.

"It's a groundbreaking find because one of the current goals of astronomy is to directly detect planet-like objects around stars like our sun," said Michael McElwain, a postdoctoral research fellow in Princeton's Department of Astrophysical Sciences who was part of the team that made the discovery. "It is also an important verification that the system -- the telescope and its instruments -- is working well."

This August 2009 discovery image of GJ 758 B was taken with the Subaru Telescope's HiCIAO instrument in the near infrared, which measures and records differences in heat. Without the special technique employed here (angular differential imaging), the star's glare would overwhelm the light from the planet candidates. The planet-like object, GJ 758 B, is circled as B in the lower right portion of the image. An unconfirmed companion planet or planet-like object, C, can be viewed above B. The star, GJ 758, is located at the center of the image, at the hub of the starburst. The graphic at the top compares the orbital distances of solar system planets. (Credit: Max Planck Institute for Astronomy/National Astronomical Observatory of Japan)

Images of the object were taken in May and August during early test runs of the new observation equipment. The team has members from Princeton, the University of Hawaii, the University of Toronto, the Max Planck Institute for Astronomy (MPIA) in Heidelberg, Germany, and the National Astronomical Observatory of Japan (NAOJ) in Tokyo. The results will be published in the Astrophysical Journal Letters.

"This challenging but beautiful detection of a very low mass companion to a sun-like star reminds us again how little we truly know about the census of gas giant planets and brown dwarfs around nearby stars," said Alan Boss, an astronomer at the Carnegie Institution for Science in Washington, D.C., who was not involved in the research. "Observations like this will enable theorists to begin to make sense of how this hitherto unseen population of bodies was able to form and evolve."

Brown dwarfs are stars that are not massive enough to sustain fusion reactions at their core, so they burn out and cool off as they age.

Aided by new varieties of viewing techniques, scientists started finding extrasolar planets (planets beyond the solar system) in 1992 and have located more than 400 planet-like objects so far. Most, however, have not been directly observed, but inferred from viewing the star around which the planet orbits. GJ 758 B is one of the first planet-like objects to be directly seen. Of the others that have been directly viewed, most have been on larger orbits than the distance between GJ 758 B and its star, or around stars with temperatures far above the average temperature of GJ 758 or our sun.

Scientists were able to spot the object even though it was hidden in the glare of the star it orbits by subtracting out that brighter light. To do this, they used the High Contrast Coronagraphic Imager with Adaptive Optics that has been attached to the Subaru Telescope. Also known as HiCIAO, it is part of a new generation of instruments specially made to detect faint objects near a bright star by masking its far more intense light. They also employed a technique known as angular differential imaging to capture the images.

"It's amazing how quickly this instrument has come online and burst into the forefront," said Marc Kuchner, an exoplanet scientist at the NASA Goddard Space Flight Center in Greenbelt, Md., who was not involved in the work. "I think this is just the beginning of what HiCIAO is going to do for the field." He added that the discovery also emphasizes that this new method of finding exoplanets -- direct detection -- is "really hitting its stride."

The planet-like object is currently at least 29 times as far from its star as the Earth is from the sun, approximately as far as Neptune is from the sun. However, further observations will be required to determine the actual size and shape of its orbit. At a temperature of only 600 F, the object is relatively "cold" for a body of its size. It is the coldest companion to a sun-like star ever recorded in an image.

The fact that such a large planet-like object appears to orbit at this location defies traditional thinking on planet formation. It is thought most larger planets are formed either closer to or farther from stars, but not in the location where GJ 758 is now. Discoveries such as this one could help theorists refine their ideas.

Telescope images also revealed a second companion to the star, which the scientists have called GJ 758 C. More observations, however, are needed to confirm whether it is nearby or just looks that way. "It looks very promising," said Christian Thalmann, one of the team's lead scientists. If it should turn out to be a second companion, he said, that would make both B and C more likely to be young planets rather than old brown dwarfs, since two brown dwarfs in such close proximity would not remain stable for such a long period of time.

Researchers from Princeton and NAOJ announced an agreement on Jan. 15 to collaborate over the next 10 years, using new equipment on the Subaru Telescope to peer into hidden corners of the nearby universe and ferret out secrets from its distant past. This research is a part of that collaboration. The HiCIAO team is led by Professor Motohide Tamura of NAOJ.

The partnership, called the NAOJ-Princeton Astrophysics Collaboration or N-PAC, provides for the exchange of scientific resources and supports a variety of long-term research projects in which the scientists from both Princeton and the Japanese astronomical community will participate on an equal basis. The collaboration builds on a decades-long tradition of scientific collaboration between Japanese and Princeton astronomers in a wide range of astronomical fields.

An important part of that partnership is the search for planets, previously hidden by the glare of stars. Finding these planets is a crucial step in answering the age-old question of the existence of extraterrestrial life.

A Window That Washes Itself? New Nano-Material May Revolutionize Solar Panels and Batteries, Too

2009-12-04T02:18:00.000-08:00

A coating on windows or solar panels that repels grime and dirt? Expanded battery storage capacities for the next electric car? New Tel Aviv University research, just published in Nature Nanotechnology, details a breakthrough in assembling peptides at the nano-scale level that could make these futuristic visions come true in just a few years.

Operating in the range of 100 nanometers (roughly one-billionth of a meter) and even smaller, graduate student Lihi Adler-Abramovich and a team working under Prof. Ehud Gazit in TAU's Department of Molecular Microbiology and Biotechnology have found a novel way to control the atoms and molecules of peptides so that they "grow" to resemble small forests of grass. These "peptide forests" repel dust and water -- a perfect self-cleaning coating for windows or solar panels which, when dirty, become far less efficient.

TAU's nanosized "forest of peptides" can be used as the basis for self-cleaning windows and more efficient batteries. (Credit: Image courtesy of American Friends of Tel Aviv University)

"This is beautiful and protean research," says Adler-Abramovich, a Ph.D. candidate. "It began as an attempt to find a new cure for Alzheimer's disease. To our surprise, it also had implications for electric cars, solar energy and construction."

As cheap as the sweetener in your soda

A world leader in nanotechnology research, Prof. Gazit has been developing arrays of self-assembling peptides made from proteins for the past six years. His lab, in collaboration with a group led by Prof. Gil Rosenman of TAU's Faculty of Engineering, has been working on new applications for this basic science for the last two years.

Using a variety of peptides, which are as simple and inexpensive to produce as the artificial sweetener aspartame, the researchers create their "self-assembled nano-tubules" in a vacuum under high temperatures. These nano-tubules can withstand extreme heat and are resistant to water.

"We are not manufacturing the actual material but developing a basic-science technology that could lead to self-cleaning windows and more efficient energy storage devices in just a few years," says Adler-Abramovich. "As scientists, we focus on pure research. Thanks to Prof. Gazit's work on beta amyloid proteins, we were able to develop a technique that enables short peptides to 'self-assemble,' forming an entirely new kind of coating which is also a super-capacitor."

As a capacitor with unusually high energy density, the nano-tech material could give existing electric batteries a boost -- necessary to start an electric car, go up a hill, or pass other cars and trucks on the highway. One of the limitations of the electric car is thrust, and the team thinks their research could lead to a solution to this difficult problem.

"Our technology may lead to a storage material with a high density," says Adler-Abramovich. "This is important when you need to generate a lot of energy in a short period of time. It could also be incorporated into today's lithium batteries," she adds.

Window Cleaner a thing of the past?

Coated with the new material, the sealed outer windows of skyscrapers may never need to be washed again -- the TAU lab's material can repel rainwater, as well as the dust and dirt it carries. The efficiency of solar energy panels could be improved as well, as a rain shower would pull away any dust that might have accumulated on the panels. It means saving money on maintenance and cleaning, which is especially a problem in dusty deserts, where most solar farms are installed today.

The lab has already been approached to develop its coating technology commercially. And Prof. Gazit has a contract with drug mega-developer Merck to continue his work on short peptides for the treatment of Alzheimer's disease -- as he had originally foreseen.

Poop-munching apes prompt quest for answers

2009-12-02T10:01:00.003-08:00

particularly well-known among rodents, rabbits and their relatives, and—less often—dogs and apes.

The participation of this last group has caused caused particular shock among human witnesses, not least because apes are supposed to be our close evolutionary relatives.

But two new studies may offer a measure of comfort. At least, such as can be found in such a dismal situation.

The studies suggest that chimps and bonobos—the two species that are our closest ape relatives—eat poop not for its own sake, but in order to retrieve hard, nutritious seeds from it.

Coprophagy may be an “adaptive feeding strategy during periods of food scarcity,” wrote Tetsuya Sakamaki of the Primate Research Institute at Kyoto University, Japan, in a study published in the Oct. 31 advance online issue of the journal Primates.

Sakamaki reported that he spent a total of no less than 1,142 hours (48 days) watching a group of about two dozen wild bonobos at the Luo Scientific Reserve in the Congo. Among them, “at least five females… practiced coprophagy and/or fecal inspection,” he wrote.

Samakaki found most of the episodes hard to see clearly, because they occurred high in trees, but he came away with the impression that the apes were trying to get at seeds. In the most clearly visible case, a young female “used her lips to extract Dialium seeds from the feces in her hand, ate the seeds, and discarded other fibrous parts in the feces,” he wrote.

Dialum plants are members of the legume family.

A study in the April 2004 issue of the journal suggested similar conclusions regarding chimpanzees, noting that similar seed types were involved: “two types of Dialium seeds were commonly found in the feces.”

The authors of this previous study added that stress, boredom or food scarcity didn’t appear to play a role in the coprophagy. Sakamaki in the more recent study mostly agreed, except he wrote that coprophagy did seem more common when food was hard to find.

Do black holes zap galaxies into existence?

2009-12-02T09:58:00.000-08:00

Which come first: the supermassive black holes that frantically devour matter, or the huge galaxies where they reside?

A new scenario has emerged to answer this contentious “‘chicken and egg’ question,” said David Elbaz of the Center for Nuclear Studies of Saclay in Gif-sur-Yvette, France, one of the researchers who developed the model.

the “black” moniker, but actually many black holes are thought to be easily visible thanks to violent activity going on around them.

Colour composite image of quasar HE0450-2958, the brightest object in the image. The image was obtained with the VISIR instrument on ESO’s Very Large Telescope, the Hubble Space Telescope and the Advanced Camera for Surveys. The quasar is believed to be zapping the object to its lower left, a galaxy, with an energetic beam of particles.

Elbaz and colleagues studied a peculiar object some five billion light years away, believed to be a black hole without a home galaxy and dubbed quasar HE0450-2958. A light year is the distance light travels in a year.

It had been speculated that the quasar’s host galaxy was hidden behind dust. The astronomers thus used an instrument on the European Southern Observatory’s Very Large Telescope designed to detect so-called mid-infrared light, which would make dust clouds brightly visible.

Yet no dust appeared, indicating there was no home galaxy, said Knud Jahnke of the Max Planck Institute for Astronomy in Heidelberg, Germany, who led the observations. “Instead we discovered that an apparently unrelated galaxy in the quasar’s immediate neighbourhood is producing stars at a frantic rate,” he said, the equivalent of about 350 Suns yearly.

Earlier observations had shown that the companion galaxy is, in fact, under fire: the quasar is spewing a jet of energetic particles towards its companion, accompanied by a stream of fast-moving gas. The injection indicates that the quasar itself might be inducing the formation of stars and thereby creating its own host galaxy, according to Elbaz and colleagues. In such a scenario, galaxies would have evolved from clouds of gas hit by the energetic jets emerging from quasars, or giant black holes.

“The two objects are bound to merge in the future: the quasar is moving at a speed of only a few tens of thousands of kilometers [or miles] per hour with respect to the companion galaxy and their separation is only about 22,000 light-years,” said Elbaz. “Although the quasar is still ‘naked’, it will eventually be ‘dressed’ when it merges with its star-rich companion. It will then finally reside inside a host galaxy like all other quasars.”

The findings may also represent the long-sought missing link to understanding why the mass of black holes is larger in galaxies that contain more stars, the researchers added. “A natural extension of our work is to search for similar objects in other systems,” said Jahnke.

The findings are being presented in new papers published in the journals Astronomy & Astrophysics and Astrophysical Journal.

Particle smasher becomes world’s most powerful

2009-12-02T09:49:00.000-08:00

After a year of troubles, the Large Hadron Collider has become the world’s highest energy particle accelerator, having accelerated its twin beams of protons to an energy about 20 percent higher than the previous world record, scientists say.

“We are still coming to terms with just how smoothly” it is working, said Rolf Heuer, Director General of CERN, the European Organization for Nuclear Research near Geneva, Switzerland, which runs the machine.

A worker inspects damage of the Large Hadron Collider magnets that occurred on Sept. 19, 2008. (Courtesy CERN)

It’s “fantastic,” he added, but “there is still a lot to do before we start physics in 2010. I’m keeping my champagne on ice until then.”
The record-breaking proton beam energy was measured at 1.18 trillion electron volts.

The developments come just 10 days after the particle smasher restarted after a year of difficulties , which began when the machine broke down in September of last year.
First beams of protons, core components of atoms, were injected into the collider on Nov. 20, researchers said. Over the following days, the machine’s operators circulated beams around the ring alternately in one direction and then the other, gradually increasing the beam lifetime to around 10 hours. Three days later, two beams circulated together for the first time, and the four big detectors recorded their first collision data.

“I was here 20 years ago when we switched on CERN’s last major particle accelerator,” the Large Electron-Positron Collider, said CERN Research and Technology Director Steve Myers. “I thought that was a great machine to operate, but this is something else. What took us days or weeks with LEP, we’re doing in hours.”

The first physics research at the LHC is scheduled for the first quarter of 2010, at a collision energy of 7 trillion electron volts (3.5 trillion electron volts per beam).

First programmable quantum computer created

2009-11-30T10:01:00.000-08:00

Using a few ultracold ions, intense lasers and some electrodes, researchers have built the first programmable quantum computer. The new system, described in a paper to be published in Nature Physics, flexed its versatility by performing 160 randomly chosen processing routines.

Earlier versions of quantum computers have been largely restricted to a narrow window of specific tasks. To be more generally useful, a quantum computer should be programmable, in the same way that a classical computer must be able to run many different programs on a single piece of machinery.

The new study is “a powerful demonstration of the technological advances towards producing a real-world quantum computer,” says quantum physicist Winfried Hensinger of the University of Sussex in Brighton, England.

Researchers led by David Hanneke of the National Institute of Standards and Technology in Boulder, Colo., based their quantum computer on two beryllium ions chilled to just above absolute zero. These ions, trapped by a magnetic field on a gold-plated aluminum chip, formed the quantum bits, or qubits, analogous to the bits in regular computers represented by 0s and 1s. Short laser bursts manipulated the beryllium ions to perform the processing operations, while nearby magnesium ions kept the beryllium ions cool and still.

Hanneke and colleagues programmed the computer to do operations on a single beryllium ion and on both of the beryllium ions together. In the quantum world, a single qubit can represent a mixture of 0 and 1 simultaneously, a state called a superposition. A laser pulse operation could change the composition of the mixture within the qubit, tipping the scales to make the qubit more likely to become a 1 when measured.

Both of the qubits together could be entangled, a situation where the two qubits are intimately linked, and what happens to one seems to affect the fate of the other. Different combinations of one- and two-qubit operations made up various programs. “We put all these pieces together and asked, what can we do with the circuit?” Hanneke says.

Hanneke and colleagues chose 160 programs for the quantum computer to run. “We picked them, quite literally, at random,” Hanneke says. “We really wanted to sample all possible operations.”

The researchers ran each program 900 times. On average, the quantum computer operated accurately 79 percent of the time, the team reported in their paper, which was published online November 15. “Getting this kind of control over a quantum system is really interesting from a physics perspective,” Hanneke says.

Earlier research has estimated that to be useful, a quantum computer must operate accurately 99.99 percent of the time. Hanneke says that with stronger lasers and other refinements, the system’s fidelity may be improved.

Experimental physicist Boris Blinov says that one of the most exciting things about the new study is that the quantum computer may be scaled up. “What’s most impressive and important is that they did it in the way that can be applied to a larger-scale system,” says Blinov, of the University of Washington in Seattle. “The very same techniques they’ve used for two qubits can be applied to much larger systems.”

South Korea's stem cell scientist found guilty of fraud

2009-11-30T09:20:00.000-08:00

SEOUL (Reuters) - A South Korean court Monday found disgraced stem cell scientist Hwang Woo-suk guilty of fraud and handed down a suspended sentence in a case that sent shockwaves throughout the global scientific community.

Hwang, once a scientist with rock-star like status for bringing South Korea to the forefront of stem cell studies, had faced trial on charges of fraud, misusing state funds and violating bioethics laws.

"He was guilty of fabrication," the Seoul court said in a verdict in the trial that stretched more than three years and included painstaking details about the scientific work Hwang and his team had performed at Seoul National University.

The court also said that Hwang illegally diverted a portion of the money he received for research for his personal use.

"But he has shown he has truly repented for his crime," the court said in its verdict. Hwang's supporters, who have packed the court for each hearing, broke into applause when the court sentenced Hwang to two years in jail, suspended for three years.

Prosecutors were seeking a four-year prison term, saying Hwang had set back scientific research and deeply embarrassed the country, which was at one point being groomed into a global center for stem cell studies.

Hwang and his lawyers did not speak to reporters.

Hwang's team was thought to have made two major breakthroughs by cloning stem cells and tailoring them to a specific patient, which raised hopes of generating genetically specific tissue to repair damaged organs or treat diseases such as Alzheimer's.

Stem cells are the body's master cells, giving rise to all the tissues, organs and blood. Embryonic stem cells are considered the most powerful kinds of stem cells, as they have the potential to give rise to any type of tissue.

An investigation team at Seoul National University said in late 2005 that Hwang's team fabricated vital data in two papers on human embryonic stem cells. Hwang resigned his post and the government revoked his stem cell research license.

With major financial backing from his supporters, Hwang went on to form SooAm Biotech Research Foundation in 2006, which specializes in animal cloning and has produced cloned dogs.

Hwang is still regarded with scorn by many in the country but has fostered a small, devoted group of followers.

"Perhaps there is a chance that he might regain trust from people through sincere work. However, the truth has come out on his manipulated research and this has been made clear," said Park Jeong-woo, a professor of bioethics at Catholic University.

Scientists Fear Nanotech Threat to Health Environment

2009-11-29T08:53:00.000-08:00

More than 30 percent of scientists surveyed expressed concern that human health may be at risk from nanotechnology, while just 20 percent of the public held such fears. Twenty percent of the scientists responding indicated a concern that new forms of nanotechnology pollution may emerge, while only 15 percent of the public thought that might be a problem.

The potential health and environmental consequences of nanotechnology are a source of greater concern to scientists than to the public at large, according to a new study published Sunday in the journal Nature Nanotechnology.

The research, which was funded by the National Science Foundation and conducted by researchers at the University of Wisconsin at Madison and Arizona State University, included a national telephone survey of American households along with a sampling of 363 leading U.S. nanotechnology scientists and engineers. It found that experts with the most insight into nanotech also have more concerns as to the health and environmental problems that might be associated with the technology.

"Scientists aren't saying there are problems," said Dietram Scheufele, a University of Wisconsin-Madison professor of life sciences communication and journalism who was lead author on the study. "They're saying, 'we don't know. The research hasn't been done.'"

Big Potential

Nanotechnology involves the manipulation of matter on the smallest scale -- on the level of molecules and atoms.
Just last month, the 2007 Nobel Prize in physics was awarded to two scientists who discovered the nanotechnology that has made today's tiny hard disk drives possible. Albert Fert of France and Peter Grünberg of Germany won the award for their independent discoveries of giant magnetoresistance (GMR), which has revolutionized the way data is read on hard disk drives by storing information in the form of microscopically small areas magnetized in different directions.

Other applications range from new antimicrobial materials and tiny probes to sample individual cells in human patients to vastly more powerful computers and lasers. Nanotechnology is already part of consumer products including golf clubs, tennis rackets and antimicrobial food storage containers.

Health Fears First

Scientists surveyed in the study were generally optimistic about the potential benefits of nanotechnology, but they expressed significantly more concern about pollution and new health problems related to the technology than members of the public did.

One example of an environmental danger could be the effect of tiny nano particles on natural environments if lab filters don't catch them when liquids are being disposed, Scheufele told TechNewsWorld.
A health concern includes the effects of nano particles whose toxicity is unknown on lab workers who get exposed to them, he added.

More than 30 percent of scientists expressed concern that human health may be at risk from the technology, while just 20 percent of the public held such fears. Twenty percent of the scientists responding indicated a concern that new forms of nanotechnology pollution may emerge, while only 15 percent of the public thought that might be a problem.

The American public, by contrast, is more worried about a potential loss of privacy from tiny new surveillance devices and the loss of more U.S. jobs, according to the research.

Information Disconnect

The bottom line, the researchers say, is that there is a disconnect between the perceptions of those who understand the technology and those of the public in general. Nanotech's emergence only recently on the nation's policy agenda and the media's lack of attention to the technology are two factors behind the disconnect, the researchers said.

"The conversation that should be taking place hasn't happened yet," Scheufele said.

"What needs to happen is really a dialog between scientists and the public and also politics that involves both the scientific and the nonscientific aspects," he explained. "That means science has to participate in a way that's accessible to all audiences."

Different groups in society are looking for different answers about technology, Scheufele added. "There isn't one single public. It's important for us to do careful research about how best to engage each of these groups."

Cultural Differences

Different cultures have varying levels of sensitivity to the introduction of unnatural elements into the natural world, noted Roger Kay, president of Endpoint Technologies.
"In Europe, for example, genetically modified foods are seen as unacceptable," Kay told TechNewsWorld. "In our highly commercial culture, on the other hand, we tend to shoot first and ask questions afterwards. Sometimes we're sorry, but most of the time it works out."
All it would take for a public-relations disaster, however, is for one of the many new technologies to get out of control, Kay added.

"Then the public will say, 'Why didn't you warn us?'" he noted. "I think scientists are aware of that."