Decision to give a group effort in the brain

Dec. 23, 2012 — A monkey would probably never agree that it is better to give than to receive, but they do apparently get some reward from giving to another monkey.

During a task in which rhesus macaques had control over whether they or another monkey would receive a squirt of fruit juice, three distinct areas of the brain were found to be involved in weighing benefits to oneself against benefits to the other, according to new research by Duke University researchers.

The team used sensitive electrodes to detect the activity of individual neurons as the animals weighed different scenarios, such as whether to reward themselves, the other monkey or nobody at all. Three areas of the brain were seen to weigh the problem differently depending on the social context of the reward. The research appears Dec. 24 in the journal Nature Neuroscience.

Using a computer screen to allocate juice rewards, the monkeys preferred to reward themselves first and foremost. But they also chose to reward the other monkey when it was either that or nothing for either of them. They also were more likely to give the reward to a monkey they knew over one they didn't, preferred to give to lower status than higher status monkeys, and had almost no interest in giving the juice to an inanimate object.

Calculating the social aspects of the reward system seems to be a combination of action by two centers involved in calculating all sorts of rewards and a third center that adds the social dimension, according to lead researcher Michael Platt, director of the Duke Institute for Brain Sciences and the Center for Cognitive Neuroscience.

The orbital frontal cortex, right above the eyes, was activated when calculating rewards to the self. The anterior cingulate sulcus in the middle of the top of the brain seemed to calculate giving up a reward. But both centers appear "divorced from social context," Platt said. A third area, the anterior cingulate gyrus (ACCg), seemed to "care a lot about what happened to the other monkey," Platt said.

Based on results of various combinations of the reward-giving scenario the monkeys were put through, it would appear that neurons in the ACCg encode both the giving and receiving of rewards, and do so in a remarkably similar way.

The use of single-neuron electrodes to measure the activity of brain areas gives a much more precise picture than brain imaging, Platt said. Even the best imaging available now is "a six-second snapshot of tens of thousands of neurons," which are typically operating in milliseconds.

What the team has seen happening is consistent with other studies of damaged ACCg regions in which animals lost their typical hesitation about retrieving food when facing social choices. This same region of the brain is active in people when they empathize with someone else.

"Many neurons in the anterior cingulate gyrus (ACCg) respond both when monkeys choose a drink for themselves and when they choose to give a drink to another monkey," Platt said. "One might view these as sort of mirror neurons for the reward system." The region is active as an animal merely watches another animal receiving a reward without having one themselves.

The research is another piece of the puzzle as neuroscientists search for the roots of charity and social behavior in our species and others. There have been two schools of thought about how the social reward system is set up, Platt said. One holds that there is generic circuitry for rewards that has been adapted to our social behavior because it helped humans and other social animals like monkeys thrive. Another school holds that social behavior is so important to humans and other highly social animals like monkeys that there may be some special circuits for it, Platt said.

This finding, in macaques that have only a very distant common ancestor with us and are "not a particularly prosocial animal," suggests that "this specialized social circuitry evolved a long time ago presumably to support cooperative behavior," Platt said.

The research was supported by grants from the Ruth K. Broad Biomedical Foundation, Canadian Institutes of Health Research, National Institute of Mental Health (MH095894), and Department of Defense (W81XWH-11-1-0584).

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Journal Reference:

Steve W C Chang, Jean-François Gariépy, Michael L Platt. Neuronal reference frames for social decisions in primate frontal cortex. Nature Neuroscience, 2012; DOI: 10.1038/nn.3287

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Italian wolves prefer pork to venison

Dec. 20, 2012 — Some European wolves have a distinct preference for wild boar over other prey, according to new research.

Scientists from Durham University, UK, in collaboration with the University of Sassari in Italy, found that the diet of wolves was consistently dominated by the consumption of wild boar which accounted for about two thirds of total prey biomass, with roe deer accounting for around a third.

The study analysed the remains of prey items in almost 2000 samples of wolf dung over a nine year period and revealed that an increase in roe deer in the wolf diet only occurred in years when boar densities were very low. In years of high roe deer densities, the wolves still preferred to catch wild boar.

The results are published in the journal PLOS ONE.

The research team related the prey remains in wolf dung to the availability of possible prey in part of Tuscany, Italy -- an area recently colonised by wolves. The findings have implications for wildlife conservation as the impact of changing predator numbers on prey species is important for managing populations of both predators and prey.

Lead author, Miranda Davis, from the School of Biological and Biomedical Sciences at Durham University, said: "Our research demonstrates a consistent selection for wild boar among wolves in the study area, which could affect other prey species such as roe deer."

"Intriguingly, in other parts of Europe where red deer are also available, wolves appear to prefer this prey to wild boar, suggesting that they discriminate between different types of venison."

In Europe, the wolf (Canis lupis) is recovering from centuries of persecution and the expansion of wolf populations has the potential to change the ecology of communities of ungulates (hooved animals) by exposing them to natural predation by wolves, according to the researchers.

The preference for boar is in contrast to other areas of Europe where wolves often avoid boar as prey. One factor may be the relatively smaller size of Mediterranean boar, making them less dangerous to wolves in Mediterranean regions, compared to the larger-sized boar that roam other parts of Europe.

Co-author, Dr Stephen Willis, from the School of Biological and Biomedical Sciences at Durham University, said: "Wolves were hunted to extinction in the UK, probably by the end of the 17th century. Our findings from Italy suggest that if they were reintroduced into an area with a healthy ungulate population their impact on livestock could be minimal."

Tuscany's woodlands support populations of both roe deer and wild boar, and are also grazed by sheep, goats and cattle; however, wild boar and roe deer made up over 95 per cent of wolf diet in the study area, with very little evidence of livestock predation.

The scientists identified prey items from fragments of bones and hair in the wolf dung collected in the region. The prey categories included wild boar, roe deer, red deer, hare, small rodents, goats, sheep and cattle.

For more than five years of the study, the percentage of wolf diet made up of wild boar was more than twice that of roe deer. Other prey represented only a very small proportion of the diet.

The researchers believe that further dietary studies are essential for understanding the true impact of wolves on European wildlife over time.

Co-author, Dr Phil Stephens, from the School of Biological and Biomedical Sciences at Durham University added: "Wolves and brown bears are gradually returning to their former strongholds in Europe. Understanding the needs of these species, as well as their potential impacts, is going to be fundamental to managing that welcome return."

The project was part-funded by a Durham University Doctoral Fellowship and the Regional Government of Tuscany and the Province of Arezzo also provided logistical support throughout the study.

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Miranda L. Davis, Philip A. Stephens, Stephen G. Willis, Elena Bassi, Andrea Marcon, Emanuela Donaggio, Claudia Capitani, Marco Apollonio. Prey Selection by an Apex Predator: The Importance of Sampling Uncertainty. PLoS ONE, 2012; 7 (10): e47894 DOI: 10.1371/journal.pone.0047894

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Hawaiian Islands are dissolving from within, study says

Dec. 21, 2012 — Most of us think of soil erosion as the primary force that levels mountains, however geologists have found that Oahu's mountains are dissolving from within due to groundwater.

Someday, Oahu's Koolau and Waianae mountains will be reduced to nothing more than a flat, low-lying island like Midway.

But erosion isn't the biggest culprit. Instead, scientists say, the mountains of Oahu are actually dissolving from within.

"We tried to figure out how fast the island is going away and what the influence of climate is on that rate," said Brigham Young University geologist Steve Nelson. "More material is dissolving from those islands than what is being carried off through erosion."

The research pitted groundwater against stream water to see which removed more mineral material. Nelson and his BYU colleagues spent two months sampling both types of sources. In addition, ground and surface water estimates from the U.S. Geological Survey helped them calculate the total quantity of mass that disappeared from the island each year.

"All of the Hawaiian Islands are made of just one kind of rock," Nelson said. "The weathering rates are variable, too, because rainfall is so variable, so it's a great natural laboratory."

Forecasting the island's future also needs to account for plate tectonics. As Oahu is pushed northwest, the island actually rises in elevation at a slow but steady rate. You've heard of mountain climbing; this is a mountain that climbs.

According to the researchers' estimates, the net effect is that Oahu will continue to grow for as long as 1.5 million years. Beyond that, the force of groundwater will eventually triumph and the island will begin its descent to a low-lying topography.

Undergraduate student Brian Selck co-authored the study, which appears in the journal Geochimica et Cosmochimica Acta. Unfortunately for him, he joined the project only after the field work in Hawaii took place.

Instead, Selck performed the mineralogical analysis of soil samples in the lab back in Provo. The island's volcanic soil contained at least one surprise in weathered rock called saprolites.

"The main thing that surprised me on the way was the appearance of a large amount of quartz in a saprolite taken from a 1-meter depth," Selck said.

After he graduates from BYU, Selck will pursue a career in hydrogeology. BYU geology professor David Tingey joins Nelson and Selck as a co-author on the new study.

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Stephen T. Nelson, David G. Tingey, Brian Selck. The denudation of ocean islands by ground and surface waters: The effects of climate, soil thickness, and water contact times on Oahu, Hawaii. Geochimica et Cosmochimica Acta, 2013; 103: 276 DOI: 10.1016/j.gca.2012.09.046

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Successful solo rock/pop stars twice as likely to die early as those in a band, study finds

Dec. 19, 2012 — Successful solo rock/pop stars are around twice as likely to die early as those in equally famous bands, indicates research published in the online journal BMJ Open.

And those who died of drug and alcohol problems were more likely to have had a difficult or abusive childhood than those dying of other causes, the findings showed.

The authors included 1489 North American and European rock and pop stars over a 50 year period between 1956 (Elivs Presley) and 2006 (Regina Spektor, The Arctic Monkeys, and Snow Patrol)

Their achievements were determined from international polls and top 40 chart successes, while details of their personal lives/childhoods were drawn from a range of music and official websites, published biographies, and anthologies.

During the 50 year period, 137 (9.2%) famous rock/pop stars died. The average age of death was 45 for North American stars and 39 for those from Europe.

The gap in life expectancy between rock and pop stars and the general population widened consistently until 25 years after fame had been achieved, after which death rates began to approach those of the general population -- but only for European stars.

Solo performers were around twice as likely to die early as those in a band, irrespective of whether they were European (9.8% vs 5.4%) or North American (22.8% vs 10.2%).

A successful solo career may be a proxy for fame, it also raises the question of whether the peer support offered by band-mates may be protective, suggest the authors.

While gender and the age at which fame was reached did not influence life expectancy, ethnicity did, with those from non-white backgrounds more likely to die early. And the chances of survival increased among those achieving fame after 1980.

Nearly half of those who died as a result of drugs, alcohol, or violence had at least one unfavourable factor in their childhoods, compared with one in four of those dying of other causes.

These factors -- referred to as adverse childhood experiences, or ACEs for short -- included physical, sexual, or emotional abuse; living with a chronically depressed, suicidal, mentally or physically ill person; living with a substance abuser; having a close relative in prison; and coming from a broken home or one in which domestic violence featured.

Four out of five dead stars with more than one unfavourable childhood factor died from substance misuse or violence-related causes.

A career as a rock/pop star may be attractive to those escaping an unhappy childhood, but it may also provide the resource to feed a predisposition to unhealthy/risky behaviours, say the authors.

"Pop/rock stars are among the most common role models for children, and surveys suggest that growing numbers aspire to pop stardom," they write. "A proliferation of TV talent shows and new opportunities created by the internet can make this dream appear more achievable than ever."

But they caution: "It is important they [children] recognise that substance use and risk taking may be rooted in childhood adversity rather than seeing them as symbols of success."

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M. A. Bellis, K. Hughes, O. Sharples, T. Hennell, K. A. Hardcastle. Dying to be famous: retrospective cohort study of rock and pop star mortality and its association with adverse childhood experiences. BMJ Open, 2012; 2 (6): e002089 DOI: 10.1136/bmjopen-2012-002089

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On-demand synaptic electronics: Circuits that learn and forget

Dec. 20, 2012 — Researchers in Japan and the US propose a nanoionic device with a range of neuromorphic and electrical multifunctions that may allow the fabrication of on-demand configurable circuits, analog memories and digital-neural fused networks in one device architecture.

Synaptic devices that mimic the learning and memory processes in living organisms are attracting avid interest as an alternative to standard computing elements that may help extend Moore's law beyond current physical limits.

However so far artificial synaptic systems have been hampered by complex fabrication requirements and limitations in the learning and memory functions they mimic. Now Rui Yang, Kazuya Terabe and colleagues at the National Institute for Materials Science in Japan and the University of California, Los Angeles, in the US have developed two-, three-terminal WO3-x-based nanoionic devices capable of a broad range of neuromorphic and electrical functions.

In its initial pristine condition the system has very high resistance values. Sweeping both negative and positive voltages across the system decreases this resistance nonlinearly, but it soon returns to its original state indicating a volatile state. Applying either positive or negative pulses at the top electrode introduces a soft-breakdown, after which sweeping both negative and positive voltages leads to non-volatile states that exhibit bipolar resistance and rectification for longer periods of time.

The researchers draw similarities between the device properties -- volatile and non-volatile states and the current fading process following positive voltage pulses -- with models for neural behaviour -- that is, short- and long-term memory and forgetting processes. They explain the behaviour as the result of oxygen ions migrating within the device in response to the voltage sweeps. Accumulation of the oxygen ions at the electrode leads to Schottky-like potential barriers and the resulting changes in resistance and rectifying characteristics. The stable bipolar switching behaviour at the Pt/WO3-x interface is attributed to the formation of the electric conductive filament and oxygen absorbability of the Pt electrode.

As the researchers conclude, "These capabilities open a new avenue for circuits, analog memories, and artificially fused digital neural networks using on-demand programming by input pulse polarity, magnitude, and repetition history."

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Rui Yang, Kazuya Terabe, Guangqiang Liu, Tohru Tsuruoka, Tsuyoshi Hasegawa, James K. Gimzewski, Masakazu Aono. On-Demand Nanodevice with Electrical and Neuromorphic Multifunction Realized by Local Ion Migration. ACS Nano, 2012; 6 (11): 9515 DOI: 10.1021/nn302510e

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How songbirds learn to sing: Mathematical model explains how birds correct mistakes to say on key

Dec. 20, 2012 — Scientists studying how songbirds stay on key have developed a statistical explanation for why some things are harder for the brain to learn than others.

"We've built the first mathematical model that uses a bird's previous sensorimotor experience to predict its ability to learn," says Emory biologist Samuel Sober. "We hope it will help us understand the math of learning in other species, including humans."

Sober conducted the research with physiologist Michael Brainard of the University of California, San Francisco.

Their results, showing that adult birds correct small errors in their songs more rapidly and robustly than large errors, were published in the Proceedings of the National Academy of Sciences (PNAS).

Sober's lab uses Bengalese finches as a model for researching the mechanisms of how the brain learns to correct vocal mistakes.

Just like humans, baby birds learn to vocalize by listening to adults. Days after hatching, Bengalese finches start imitating the sounds of adults. "At first, their song is extremely variable and disorganized," Sober says. "It's baby talk, basically."

The young finches keep practicing, listening to their own sounds and fixing any mistakes that occur, until eventually they can sing like their elders.

Young birds, and young humans, make a lot of big mistakes as they learn to vocalize. As birds and humans get older, the variability of mistakes shrinks. One theory contends that adult brains tend to screen out big mistakes and pay more attention to smaller ones.

"To correct any mistake, the brain has to rely on the senses," Sober explains. "The problem is, the senses are unreliable. If there is noise in the environment, for example, the brain may think it misheard and ignore the sensory experience."

The link between variability and learning may explain why youngsters tend to learn faster and why adults are more resistant to change.

"Whether you are an opera singer or a bird, there is always variability in your sounds," Sober says. "When the brain receives an error in pitch, it seems to use this very simple and elegant strategy of evaluating the probability of whether the error was just extraneous 'noise,' a problem reading the signal, or an actual mistake in the vocalization."

The researchers wanted to quantify the relationship between the size of a vocal error, and the probability of the brain making a sensorimotor correction. The experiments were conducted on adult Bengalese finches outfitted with light-weight, miniature headphones.

As a bird sang into a microphone, the researchers used sound-processing equipment to trick the bird into thinking it was making vocal mistakes, by changing the bird's pitch and altering the way the bird heard itself, in real-time.

"When we made small pitch shifts, the birds learned really well and corrected their errors rapidly," Sober says. "As we made the pitch shifts bigger, the birds learned less well, until at a certain pitch, they stopped learning."

The researchers used the data to develop a statistical model for the size of a vocal error and whether a bird learns, including the cut-off point for learning from sensorimotor mistakes. They are now developing additional experiments to test and refine the model.

"We hope that our mathematical framework for how songbirds learn to sing could help in the development of human behavioral therapies for vocal rehabilitation, as well as increase our general understanding of how the brain learns," Sober says.

The research was supported by grants from the National Institute of Deafness and Communications Disorders, the National Institute of Neurological Diseases and Stroke and the National Institute of Mental Health.

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The above story is reprinted from materials provided by Emory University. The original article was written by Carol Clark.

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S. J. Sober, M. S. Brainard. Vocal learning is constrained by the statistics of sensorimotor experience. Proceedings of the National Academy of Sciences, 2012; 109 (51): 21099 DOI: 10.1073/pnas.1213622109

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From farm to table, mealworms may be the next best food

Dec. 19, 2012 — Food enthusiasts interested in sustainable farm practices may soon have a new meat alternative: insects. Beetle larvae (called mealworms) farms produce more edible protein than traditional farms for chicken, pork, beef or milk, for the same amount of land used, according to research published Dec. 19 in the open-access journal PLOS ONE by Dennis Oonincx and colleagues from the University of Wageningen, Netherlands.

The researchers compared the environmental impact of meat production on a mealworm farm to traditional animal farms using three parameters: Land usage, energy needs, and greenhouse gas emissions. From the start of the process to the point that the meat left the farm, they found that mealworms scored better than the other foods. Per unit of edible protein produced, mealworm farms required less land and similar amounts of energy.

Previous work by the same team, published in PLOS ONE in 2010, has already shown that mealworms themselves produce less greenhouse gases than other animals grown for meat. In this new study, the researchers elaborate on the sustainability of insect proteins as a food by showing that growing mealworms for animal protein requires less land and generate fewer greenhouse gas emissions than chicken, pork, beef or milk.

Commenting on their results, Oonincx adds, "Since the population of our planet keeps growing, and the amount of land on this earth is limited, a more efficient, and more sustainable system of food production is needed. Now, for the first time it has been shown that mealworms, and possibly other edible insects, can aid in achieving such a system."

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Dennis G. A. B. Oonincx, Imke J. M. de Boer. Environmental Impact of the Production of Mealworms as a Protein Source for Humans – A Life Cycle Assessment. PLoS ONE, 2012; 7 (12): e51145 DOI: 10.1371/journal.pone.0051145

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Archaeologists date world's oldest timber constructions

Dec. 20, 2012 — A research team led by Willy Tegel and Dr. Dietrich Hakelberg from the Institute of Forest Growth of the University of Freiburg has succeeded in precisely dating four water wells built by the first Central European agricultural civilization with the help of dendrochronology or growth ring dating. The wells were excavated at settlements in the Greater Leipzig region and are the oldest known timber constructions in the world. They were built by the Linear Pottery culture, which existed from roughly 5600 to 4900 BC.

The team's findings, which have been published in the international scientific journal PLoS ONE, afford new insight into prehistoric technology. The study was conducted by archaeologists and dendrochronologists from the Institute of Forest Growth in Freiburg, the Archaeological Heritage Office of Saxony in Dresden, and the Swiss Federal Research Institute WSL in Birmensdorf, Switzerland.

The four early Neolithic wells were constructed from oak wood. In addition to the timber, many other waterlogged organic materials, such as plant remains, wooden artifacts, bark vessels, and bast fiber cords, as well as an array of richly decorated ceramic vessels, have survived for millennia hermetically sealed below groundwater level. With the help of dendrochronology, the scientists were able to determine the exact felling years of the trees and thus also the approximate time at which the wells were constructed.

The tests revealed that the wood comes from massive old oak trees felled by early Neolithic farmers with stone adzes between the years of 5206 and 5098 BC. The farmers cleaved the trunks into boards, assembling them to make chest-like well linings with complex corner joints. Using state-of-the-art laser scanning technology, the scientists collected data on the timbers and tool marks and documented the highly developed woodworking skills of the early Neolithic settlers. The very well-preserved tool marks and timber joints testify to unexpectedly sophisticated timber construction techniques.

In the course of the sixth millennium BC, the nomadic hunting and gathering lifestyle gave way to a sedentary lifestyle with agriculture and stock breeding in Central Europe. This break in the history of humankind has been termed the "Neolithic Revolution." A sedentary lifestyle required permanent housing, and houses are inconceivable without a developed woodworking technology -- in other words, the first farmers were also the first carpenters. Until now, however, archaeologists have only succeeded in unearthing the soil marks left by their houses.

The precisely dated wells will enable scientists to conduct more detailed studies on the important role of timber construction techniques for humankind's adoption of a sedentary lifestyle.

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Willy Tegel, Rengert Elburg, Dietrich Hakelberg, Harald Stäuble, Ulf Büntgen. Early Neolithic Water Wells Reveal the World's Oldest Wood Architecture. PLoS ONE, 2012; 7 (12): e51374 DOI: 10.1371/journal.pone.0051374

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Around two queries a week to UK poisons service concern . . . snakebites

Dec. 19, 2012 — Snakebite injuries account for around two phone queries every week to the UK National Poisons Information Service, indicates an audit published online in Emergency Medicine Journal.

Changes in data recording mean that these figures are probably an underestimate of the true numbers of snakebite injuries in the UK, suggest the authors.

They audited telephone enquiries made to the Cardiff, Edinburgh, Birmingham and Newcastle units of the UK National Poisons Information Service (NPIS) between 2004 and 2010.

Some 510 calls about snakebites were made during this period, over half of which (52%) concerned the European adder (Vipera Berus), the only poisonous snake that is native to the UK.

Although poisonous, an adder snakebite is rarely fatal, with only 14 deaths attributed to its bite since 1856, but a bite can nevertheless be serious because of its effects on the heart and consequently other organs, and excessive localised swelling.

One in four of the enquiries (26%) were about exotic snakes that had been imported and kept as pets. The most common of these were corn or rat snakes (27%), boas (20%), pythons (20%) and western hognose (11%).

Three per cent of the exotic snake bites were from poisonous snakes, including rattlesnakes and green mambas. The rest of the cases concerned other UK native, non-poisonous snakes (4%) and unidentified snakes (18%).

The average age of the injured was 32, but ranged from under a year to 87, with two thirds of them occurring in men and boys. Enquiries peaked in August (19%).

Almost half the enquiries (42%) concerned the consequences of a poisonous bite, with 85 cases deemed in need of anti-venom.

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J. M. Coulson, G. Cooper, C. Krishna, J. P. Thompson. Snakebite enquiries to the UK National Poisons Information Service: 2004-2010. Emergency Medicine Journal, 2012; DOI: 10.1136/emermed-2012-201587

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Super-fine sound beam could one day be an invisible scalpel

Dec. 19, 2012 — A carbon-nanotube-coated lens that converts light to sound can focus high-pressure sound waves to finer points than ever before. The University of Michigan engineering researchers who developed the new therapeutic ultrasound approach say it could lead to an invisible knife for noninvasive surgery.

Today's ultrasound technology enables far more than glimpses into the womb. Doctors routinely use focused sound waves to blast apart kidney stones and prostate tumors, for example. The tools work primarily by focusing sound waves tightly enough to generate heat, says Jay Guo, a professor of electrical engineering and computer science, mechanical engineering, and macromolecular science and engineering. Guo is a co-author of a paper on the new technique published in the current issue of Nature's journal Scientific Reports.

The beams that today's technology produces can be unwieldy, says Hyoung Won Baac, a research fellow at Harvard Medical School who worked on this project as a doctoral student in Guo's lab.

"A major drawback of current strongly focused ultrasound technology is a bulky focal spot, which is on the order of several millimeters," Baac said. "A few centimeters is typical. Therefore, it can be difficult to treat tissue objects in a high-precision manner, for targeting delicate vasculature, thin tissue layer and cellular texture. We can enhance the focal accuracy 100-fold."

The team was able to concentrate high-amplitude sound waves to a speck just 75 by 400 micrometers (a micrometer is one-thousandth of a millimeter). Their beam can blast and cut with pressure, rather than heat. Guo speculates that it might be able to operate painlessly because its beam is so finely focused it could avoid nerve fibers. The device hasn't been tested in animals or humans yet, though.

"We believe this could be used as an invisible knife for noninvasive surgery," Guo said. "Nothing pokes into your body, just the ultrasound beam. And it is so tightly focused, you can disrupt individual cells."

To achieve this superfine beam, Guo's team took an optoacoustic approach that converts light from a pulsed laser to high-amplitude sound waves through a specially designed lens. The general technique has been around since Thomas Edison's time. It has advanced over the centuries, but for medical applications today, the process doesn't normally generate a sound signal strong enough to be useful.

The U-M researchers' system is unique because it performs three functions: it converts the light to sound, focuses it to a tiny spot and amplifies the sound waves. To achieve the amplification, the researchers coated their lens with a layer of carbon nanotubes and a layer of a rubbery material called polydimethylsiloxane. The carbon nanotube layer absorbs the light and generates heat from it. Then the rubbery layer, which expands when exposed to heat, drastically boosts the signal by the rapid thermal expansion.

The resulting sound waves are 10,000 times higher frequency than humans can hear. They work in tissues by creating shockwaves and microbubbles that exert pressure toward the target, which Guo envisions could be tiny cancerous tumors, artery-clogging plaques or single cells to deliver drugs. The technique might also have applications in cosmetic surgery.

In experiments, the researchers demonstrated micro ultrasonic surgery, accurately detaching a single ovarian cancer cell and blasting a hole less than 150 micrometers in an artificial kidney stone in less than a minute.

"This is just the beginning," Guo said. "This work opens a way to probe cells or tissues in much smaller scale."

The researchers will present the work at the SPIE Photonics West meeting in San Francisco. The research was funded by the National Science Foundation and the National Institutes of Health.

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Hyoung Won Baac, Jong G. Ok, Adam Maxwell, Kyu-Tae Lee, Yu-Chih Chen, A. John Hart, Zhen Xu, Euisik Yoon, L. Jay Guo. Carbon-Nanotube Optoacoustic Lens for Focused Ultrasound Generation and High-Precision Targeted Therapy. Scientific Reports, 2012; 2 DOI: 10.1038/srep00989

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Dragonflies have human-like 'selective attention'

Dec. 20, 2012 — In a discovery that may prove important for cognitive science, our understanding of nature and applications for robot vision, researchers at the University of Adelaide have found evidence that the dragonfly is capable of higher-level thought processes when hunting its prey.

The discovery, to be published online December 20 in the journal Current Biology, is the first evidence that an invertebrate animal has brain cells for selective attention, which has so far only been demonstrated in primates.

Dr Steven Wiederman and Associate Professor David O'Carroll from the University of Adelaide's Centre for Neuroscience Research have been studying insect vision for many years.

Using a tiny glass probe with a tip that is only 60 nanometers wide -- 1500 times smaller than the width of a human hair -- the researchers have discovered neuron activity in the dragonfly's brain that enables this selective attention.

They found that when presented with more than one visual target, the dragonfly brain cell 'locks on' to one target and behaves as if the other targets don't exist.

"Selective attention is fundamental to humans' ability to select and respond to one sensory stimulus in the presence of distractions," Dr Wiederman says.

"Imagine a tennis player having to pick out a small ball from the crowd when it's traveling at almost 200kms an hour -- you need selective attention in order to hit that ball back into play.

"Precisely how this works in biological brains remains poorly understood, and this has been a hot topic in neuroscience in recent years," he says.

"The dragonfly hunts for other insects, and these might be part of a swarm -- they're all tiny moving objects. Once the dragonfly has selected a target, its neuron activity filters out all other potential prey. The dragonfly then swoops in on its prey -- they get it right 97% of the time."

Associate Professor O'Carroll says this brain activity makes the dragonfly a more efficient and effective predator.

"What's exciting for us is that this is the first direct demonstration of something akin to selective attention in humans shown at the single neuron level in an invertebrate," Associate Professor O'Carroll says.

"Recent studies reveal similar mechanisms at work in the primate brain, but you might expect it there. We weren't expecting to find something so sophisticated in lowly insects from a group that's been around for 325 million years.

"We believe our work will appeal to neuroscientists and engineers alike. For example, it could be used as a model system for robotic vision. Because the insect brain is simple and accessible, future work may allow us to fully understand the underlying network of neurons and copy it into intelligent robots," he says.

Video: http://www.youtube.com/watch?v=iyMU6wfSBTI&feature=youtu.be

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Steven D. Wiederman, David C. O’Carroll. Selective Attention in an Insect Visual Neuron. Current Biology, 2012; DOI: 10.1016/j.cub.2012.11.048

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Peel-and-stick solar panels: Decal-like application process allows thin, flexible solar panels to be applied to virtually any surface

Dec. 20, 2012 — For all their promise, solar cells have frustrated scientists in one crucial regard -- most are rigid. They must be deployed in stiff, often heavy, fixed panels, limiting their applications. So researchers have been trying to get photovoltaics to loosen up. The ideal: flexible, decal-like solar panels that can be peeled off like band-aids and stuck to virtually any surface, from papers to window panes.

Now the ideal is real. Stanford researchers have succeeded in developing the world's first peel-and-stick thin-film solar cells. The breakthrough is described in a paper in the December 20th issue of Scientific Reports.

Unlike standard thin-film solar cells, the peel-and-stick version from Stanford does not require any direct fabrication on the final carrier substrate. This is a far more dramatic development than it may initially seem. All the challenges associated with putting solar cells on unconventional materials are avoided with the new process, vastly expanding the potential applications of solar technology.

Thin-film photovoltaic cells are traditionally fixed on rigid silicon and glass substrates, greatly limiting their uses, says Chi Hwan Lee, lead author of the paper and a PhD candidate in mechanical engineering. And while the development of thin-film solar cells promised to inject some flexibility into the technology, explains Xiaolin Zheng, a Stanford assistant professor of mechanical engineering and senior author of the paper, scientists found that use of alternative substrates was problematic in the extreme.

"Nonconventional or 'universal' substrates are difficult to use for photovoltaics because they typically have irregular surfaces and they don't do well with the thermal and chemical processing necessary to produce today's solar cells," Zheng observes. "We got around these problems by developing this peel-and-stick process, which gives thin-film solar cells flexibility and attachment potential we've never seen before, and also reduces their general cost and weight."

Utilizing the process, Zheng continues, researchers attached their solar cells to paper, plastic and window glass among other materials.

"It's significant that we didn't lose any of the original cell efficiency," Zheng said.

The new process involves a unique silicon, silicon dioxide and metal "sandwich." First, a 300-nanometer film of nickel (Ni) is deposited on a silicon/silicon dioxide (Si/SiO2) wafer. Thin-film solar cells are then deposited on the nickel layer utilizing standard fabrication techniques, and covered with a layer of protective polymer. A thermal release tape is then attached to the top of the thin-film solar cells to augment their transfer off of the production wafer and onto a new substrate.

The solar cell is now ready to peel from the wafer. To remove it, the wafer is submerged in water at room temperature and the edge of the thermal release tape is peeled back slightly, allowing water to seep into and penetrate between the nickel and silicon dioxide interface. The solar cell is thus freed from the hard substrate but still attached to the thermal release tape. Zheng and team then heat the tape and solar cell to 90°C for several seconds, then the cell can be applied to virtually any surface using double-sided tape or other adhesive. Finally, the thermal release tape is removed, leaving just the solar cell attached to the chosen substrate.

Tests have demonstrated that the peel-and-stick process reliably leaves the thin-film solar cells wholly intact and functional, Zheng said. "There's also no waste. The silicon wafer is typically undamaged and clean after removal of the solar cells, and can be reused."

While others have been successful in fabricating thin-film solar cells on flexible substrates before, those efforts have required modifications of existing processes or materials, noted Lee. "The main contribution of our work is we have done so without modifying any existing processes, facilities or materials, making them viable commercially. And we have demonstrated our process on a more diverse array of substrates than ever before," Lee said.

"Now you can put them on helmets, cell phones, convex windows, portable electronic devices, curved roofs, clothing -- virtually anything," said Zheng.

Moreover, peel-and-stick technology isn't necessarily restricted to thin-film solar cells, Zheng said. The researchers believe the process can also be applied to thin-film electronics, including printed circuits and ultra thin transistors and LCDs.

"Obviously, a lot of new products -- from 'smart' clothing to new aerospace systems -- might be possible by combining both thin-film electronics and thin-film solar cells," observed Zheng. "And for that matter, we may be just at the beginning of this technology. The peel-and-stick qualities we're researching probably aren't restricted to Ni/SiO2. It's likely many other material interfaces demonstrate similar qualities, and they may have certain advantages for specific applications. We have a lot left to investigate."

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Biological concrete for constructing 'living' building materials with lichens, mosses

Dec. 20, 2012 — The Structural Technology Group has developed and patented a type of biological concrete that supports the natural, accelerated growth of pigmented organisms. The material, which has been designed for the façades of buildings or other constructions in Mediterranean climates, offers environmental, thermal and aesthetic advantages over other similar construction solutions. The material improves thermal comfort in buildings and helps to reduce atmospheric CO2 levels.

In studying this concrete, the researchers at the Structural Technology Group of the Universitat Politècnica de Catalunya • BarcelonaTech (UPC) have focused on two cement-based materials. The first of these is conventional carbonated concrete (based on Portland cement), with which they can obtain a material with a pH of around 8. The second material is manufactured with a magnesium phosphate cement (MPC), a hydraulic conglomerate that does not require any treatment to reduce its pH, since it is slightly acidic.

On account of its quick setting properties, magnesium phosphate cement has been used in the past as a repair material. It has also been employed as a biocement in the field of medicine and dentistry, indicating that it does not have an additional environmental impact.

The innovative feature of this new (vertical multilayer) concrete is that it acts as a natural biological support for the growth and development of certain biological organisms, to be specific, certain families of microalgae, fungi, lichens and mosses.

Having patented the idea, the team is investigating the best way to promote the accelerated growth of these types of organisms on the concrete. The goal of the research is to succeed in accelerating the natural colonisation process so that the surface acquires an attractive appearance in less than a year. A further aim is that the appearance of the façades constructed with the new material should evolve over time, showing changes of colour according to the time of year and the predominant families of organisms. On these kinds of buildings, other types of vegetation are prevented from appearing, lest their roots damage construction elements.

Three layers of material

In order to obtain the biological concrete, besides the pH, other parameters that influence the bioreceptivity of the material have been modified, such as porosity and surface roughness. The result obtained is a multilayer element in the form of a panel which, in addition to a structural layer, consists of three other layers: the first of these is a waterproofing layer situated on top of the structural layer, protecting the latter from possible damage caused by water seeping through.

The next layer is the biological layer, which supports colonisation and allows water to accumulate inside it. It acts as an internal microstructure, aiding retention and expelling moisture; since it has the capacity to capture and store rainwater, this layer facilitates the development of biological organisms.

The final layer is a discontinuous coating layer with a reverse waterproofing function. This layer permits the entry of rainwater and prevents it from escaping; in this way, the outflow of water is redirected to where it is aimed to obtain biological growth.

CO2 reduction

The new material, which has various applications, offers environmental, thermal and aesthetic advantages, according to the research team led by Antonio Aguado and supported by Ignacio Segura and Sandra Manso. From an environmental perspective, the new concrete absorbs and therefore reduces atmospheric CO2, thanks to its biological coating.

At the same time, it has the capacity to capture solar radiation, making it possible to regulate thermal conductivity inside the buildings depending on the temperature reached. The biological concrete acts not only as an insulating material and a thermal regulator, but also as an ornamental alternative, since it can be used to decorate the façade of buildings or the surface of constructions with different finishes and shades of colour; it has been designed for the colonisation of certain areas with a variety of colours, without the need to cover an entire surface. The idea is to create a patina in the form of a biological covering or a "living" painting.

There are also possibilities for its use in garden areas as a decorative element and as a sustainable means of blending buildings and constructions into the landscape.

Architectural renovation

The material lends itself to a new concept of vertical garden, not only for newly built constructions, but also for the renovation of existing buildings. Unlike the current vegetated façade and vertical garden systems, the new material supports biological growth on its own surface; therefore, complex supporting structures are not required, and it is possible to choose the area of the façade to which the biological growth is to be applied.

Vegetated façades and vertical gardens depend on a plant substrate in some type of container, or they use cultures that are totally substrate-independent, such as hydroponic cultures. However, they require complex systems attached to the construction itself (layers of material) and even adjacent structures made of metal or plastic. This can lead to complications associated with additional loads, the reduction of light, or the reduction of space around the building. With the new "green" concrete, the organisms can grow directly on the multi-layered material.

Patent and commercialisation The research has led to a doctoral thesis, which Sandra Manso is writing. At present, the experimental campaign corresponding to the phase of biological growth is being conducted, and this will be completed at the UPC and the University of Ghent (Belgium). This research has received support from Antonio Gómez Bolea, a lecturer in the Faculty of Biology at the University of Barcelona, who has made contributions in the field of biological growth on construction materials.

At present, a patent is in the process of being obtained for this innovative product, and the Catalan company ESCOFET 1886 S.A., a manufacturer of concrete panels for architectural and urban furniture purposes, has already shown an interest in commercialising the material.

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Inspiration from a porcupine's quills

Dec. 10, 2012 — Anyone unfortunate enough to encounter a porcupine's quills knows that once they go in, they are extremely difficult to remove. Researchers at MIT and Brigham and Women's Hospital now hope to exploit the porcupine quill's unique properties to develop new types of adhesives, needles and other medical devices.

In a new study, the researchers characterized, for the first time, the forces needed for quills to enter and exit the skin. They also created artificial devices with the same mechanical features as the quills, raising the possibility of designing less-painful needles, or adhesives that can bind internal tissues more securely.

There is a great need for such adhesives, especially for patients who have undergone gastric-bypass surgery or other types of gastric or intestinal surgery, according to the researchers. These surgical incisions are now sealed with sutures or staples, which can leak and cause complications.

"With further research, biomaterials modeled based on porcupine quills could provide a new class of adhesive materials," says Robert Langer, the David H. Koch Institute Professor at MIT and a senior author of the study, which appears this week in the Proceedings of the National Academy of Sciences.

Jeffrey Karp, an associate professor of medicine at Harvard Medical School and co-director of the Center for Regenerative Therapeutics at Brigham and Women's Hospital, is also a senior author of the paper. Lead author is Woo Kyung Cho, a postdoc in the Harvard-MIT Division of Health Sciences and Technology (HST).

Borrowing from nature

Aside from stitches and sutures, doctors sometimes use medical-grade superglue to bind tissue together, Karp says. However, those glues can be toxic, or provoke an inflammatory response.

To create adhesives that would work in the body without producing adverse reactions, the research team turned to nature for inspiration. "We believe that evolution is the best problem-solver," Karp says.

In this case, they became interested in the North American porcupine, which has about 30,000 barbed quills to defend against predators. Each quill is several centimeters long; the four millimeters at the very tip are covered in microscopic barbs.

To their surprise, the researchers found that despite the difficulty of removing the quills, they require very little force to penetrate tissue. Compared to quills with no barbs, the barbed quills require 60 to 70 percent less force to penetrate muscle tissue.

The team then set out to determine how the quills achieve this unique combination of easy penetration and difficult removal. "By understanding the mechanism, we can design an artificial system in the right way," Cho says.

They found that the tiny barbs at the end of the quill are the key to both ease of penetration and resistance to removal. While the quill is entering tissue, the barbs act to localize the penetration forces, allowing them to tear through tissue fibers much more easily -- just as a serrated knife cuts through tomato skin far more cleanly than a straight-edged knife.

When it comes to the force required for pullout, the barbs act like anchors that keep the quill from coming out. The force required to pull out barbed quills is four times that required to remove barbless quills.

Toward new adhesives

To explore the possibility of making stronger adhesives, the researchers created a patch with an array of barbed quills on one side. They found that the energy required to remove this patch was 30 times greater than that needed for a control patch, which had quills but no barbs.

The system could also be tweaked so that it penetrates tissue easily but is not as difficult to remove as a porcupine quill, enabling design of less-painful needles for injections. "If you can still create the stress concentrations but without having a barb that catches tissue on removal, potentially you could create something with just easy insertion, without the adhesion," says James Ankrum, a graduate student in HST and an author of the paper.

Langer and Karp introduced the concept of gecko-inspired medical bandages in 2008; however, "these require a reactive glue to adhere to wet tissues, while porcupine-quill-inspired adhesives attach to tissues beautifully without requiring the use of reactive chemistry," Karp says. "They are extremely versatile and potentially universal in their application."

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Woo Kyung Cho, James A. Ankrum, Dagang Guo, Shawn A. Chester, Seung Yun Yang, Anurag Kashyap, Georgina A. Campbell, Robert J. Wood, Ram K. Rijal, Rohit Karnik, Robert Langer, and Jeffrey M. Karp. Microstructured barbs on the North American porcupine quill enable easy tissue penetration and difficult removal. PNAS, December 10, 2012 DOI: 10.1073/pnas.1216441109

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Black holes have properties that resemble dynamics of both solids and liquids

Dec. 11, 2012 — Black holes are surrounded by many mysteries, but now researchers from the Niels Bohr Institute, among others, have come up with new groundbreaking theories that can explain several of their properties. The research shows that black holes have properties that resemble the dynamics of both solids and liquids.

The results are published in the scientific journal, Physical Review Letters.

Black holes are extremely compact objects in the universe. They are so compact that they generate an incredibly strong gravitational pull and everything that comes near them is swallowed up. Not even light can escape, so light that hits a black hole will not be reflected, but will be entirely absorbed, as a result, they cannot be seen and we call them black holes.

"But black holes are not completely black, because we know that they emit radiation and there are indications that the radiation is thermal, i.e. it has a temperature," explains Niels Obers, a professor of theoretical particle physics and cosmology at the Niels Bohr Institute at the University of Copenhagen.

Multiple dimensions

Researchers know that the black holes are very compact, but they do not know what their quantum properties are. Niels Obers works with theoretical modelling to better understand the physics of black holes. He explains that you can look at a black hole like a particle. A particle has in principle no dimensions. It is a point. If you give a particle an extra dimension, it becomes a string. If you give the string an extra dimension, it becomes a plane. Physicists call such a plane a 'brane' (the word 'brane' is related to 'membrane' from the biological world).

"In string theory, you can have different branes, including planes that behave like black holes, which we call black branes. The black branes are thermal, that is to say, they have a temperature and are dynamical objects. When black branes are folded into multiple dimensions, they form a 'blackfold'," explains Niels Obers, who worked out this new way of looking at black branes with associate professor in theoretical physics at the Niels Bohr Institute, Troels Harmark, back in 2009.

New breakthrough

Niels Obers and his two doctoral students Jay Armas and Jakob Gath have now made a new breakthrough in the description of the physics of black holes based on the theories of the black branes and blackfolds,

"The black branes are hydro-dynamic objects, that is to say that they have the properties of a liquid. We have now discovered that black branes also have properties, which can be explained in terms of solids. They can behave like elastic material when we bend them," explains Jay Armas.

He explains that when the black branes are bent and folded into a blackfold, a so-called piezoelectric effect (electricity that occurs due to pressure) is created. This new effect can be understood as a slightly bent and charged black string with a greater concentration of electric charge on the innermost side in relation to the outermost side. This produces two electrically charged poles on the black strings. Black holes are predicted by Einstein's theory of gravity. This means that there is a very surprising relationship between gravity and fluid mechanics and solid-state physics.

"With these new theories, we expect to be able to explain other black hole phenomena, and we expect to be able to better understand the physical properties of neutron stars. We also expect to gain a greater understanding of the so-called particle theories, which are, for example, relevant for understanding the quark-gluon-plasma in the primordial universe," explains Niels Obers.

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Jay Armas, Jakob Gath, Niels Obers. Black Branes as Piezoelectrics. Physical Review Letters, 2012; 109 (24) DOI: 10.1103/PhysRevLett.109.241101

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Noise power on adhesion: New model may help robotic fingers, made of a soft surface, manipulate small objects

Dec. 17, 2012 — Imagine a solid ball rolling down a slightly inclined ramp. What could be perceived as child's play is the focus of serious theoretical research by Manoj Chaudhury and Partho Goohpattader, two physicists from Lehigh University, Bethlehem, Pennsylvania, USA.

Their study, which is about to be published in EPJ E, has one thing in common with childhood behaviour. It introduces a mischievous idea, namely studying the effect of random noise, such as vibrations, on the ball. They found it could lower the energy barrier to set the ball in motion.

The authors used a ramp with a micro-textured surface. This surface is akin to that of a gecko's feet, made of so-called microfibrils capable of adhering to any surface by deforming elastically. They then studied the effect of vibration on a ball left on the top of such a textured ramp. They found that the sphere starts rolling when subjected to a computer-generated random vibration. To set the ball in motion requires activation energy, the model shows. It has been long known that the same applies to the adhesion of molecules, on a much smaller scale, as predicted theoretically by the so-called Arrhenius kinetics. This study pinpoints a finite threshold of intensity for the vibration noise above which the ball is set in motion.

This finding could have implications for the removal of water droplets from super-hydrophobic surfaces such as plant leaves. Other applications could also include gecko feet-mimetic adhesives, better adhesion of rubber tires on roads, and the use of fluids, instead of electronics, to perform a digital operation. In addition, new MicroElectroMechanical systems (MEMs), based on robotic fingers capable of displacing a small object, could be assisted by noise.

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M. K. Chaudhury, P. S. Goohpattader. Noise-activated dissociation of soft elastic contacts. The European Physical Journal E, 2012; 35 (12) DOI: 10.1140/epje/i2012-12131-9

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Micro sensors help underwater robots swim like fish

Dec. 12, 2012 — NTU scientists have invented a 'sense-ational' device, similar to a string of 'feelers' found on the bodies of the Blind Cave Fish, which enables the fish to sense their surrounding and so navigate easily.

Using a combination of water pressure and computer vision technology, the sensory device is able to give users a 3-D image of nearby objects and map its surroundings. The possible applications of this fish-inspired sensor are enormous. The sensor can potentially replace the expensive 'eyes and ears' on Autonomous Underwater Vehicles (AUVs), submarines and boats that currently rely on cameras and sonars to gather information about the environment around them.

The revolutionary, low-powered sensor is unlike cameras which cannot see in dark or murky waters; or sonars whose sound waves pose harm to some marine animals.

These extremely small sensors (each sensor is 1.8mm x 1.8mm) are now being used in AUVs developed by researchers from Singapore-MIT Alliance for Research and Technology (SMART), a research centre funded by the National Research Foundation. The centre is developing a new generation of underwater 'stingray-like' robots and autonomous surface vessels.

The new sensors, made using Microelectromechanical Systems (MEMS) technology, will make such robots smarter and prolong their operational time as battery power is conserved.

Associate Professor Miao Jianminfrom the School of Mechanical and Aerospace Engineering, and his team of four have spent the last five years in collaboration with SMART to develop micro-sensors that mimic the row of 'feelers' on both sides of the Blind cave fish's body.

Associate Prof Miao said the line of sensors present on the fish's body is the reason why it can sense objects around it and still travel at high speeds without colliding with any underwater obstacles.

"To mimic nature, our team created microscopic sensory pillars wrapped in hydrogel -- a material which is similar to the natural neuromasts of the blind cave fish -- into an array of two rows of five sensors," Prof Miao said.

"This array of micro-sensors will then allow AUVs to locate, identify, and classify obstacles and objects in water through water pressure and also to optimise its movement in water by sensing the water flow."

The new sensor array which costs below S$100 to make, is also more affordable than sonars, which can detect faraway objects but not nearby objects and cost thousands of dollars.

Partnering Prof Miao to develop the sensors and to adopt it for use on AUVs is Professor Michael Triantafyllou from SMART. Prof Triantafyllou, from SMART's Centre for Environmental Sensing and Modeling (CENSAM), is one of the world's foremost experts on creating underwater robots modelled after aquatic animals like fish.

Current problems with AUVs include poor navigation in murky or cloudy waters such as those off the coast of Singapore, as underwater cameras can only see a short distance, Prof Triantafyllou said.

"Other methods like underwater lights and cameras, acoustic navigation, and sonars also work, but they are very expensive and require very high levels of power that drain the batteries. The new sensors are much cheaper and only require small amounts of power. Also, sensors like sonar are loud and invasive and they may harm aquatic animals that also use sound waves to navigate," the Massachusetts Institute of Technology professor added.

The aim of the AUVs is for environmental sensing, to detect environmental pollution, contaminants and to monitor the overall water quality in Singapore's waters. The AUVs will have chemical sensors installed to detect the chemical condition of water (dissolved oxygen, nutrients, metals, oils, and pesticides), and biological sensors to monitor water conditions such as harmful bacteria and pathogens.

Other potential application of these MEMS sensors, which specialises in near-field detection include defence applications. These can detect nearby submarines without the use of sonar thatgives away one's location.

This collaborative research resulted in two breakthrough papers being accepted for presentation at a MEMS conference next January in Taiwan, organised by the Institute of Electrical and Electronics Engineers (IEEE).

One paper is for the development of the piezoelectric sensor which does not require any energy as it generates an electric voltage when water flows past the 'feelers'. The second paper focuses on a low-powered biomimetic sensor which can detect underwater objects even when there is little water flowing past it.

To further improve the sensor, Prof Miao's team is now looking to develop a hybrid sensor which will combine both the zero-energy piezoelectric sensor's high accuracy with the low-powered static sensor's ability to detect objects in still water.

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Three new species of venomous primate identified; May help protect rare primate from illegal trades

Dec. 14, 2012 — A venomous primate with two tongues would seem safe from the pet trade, but the big-eyed, teddy-bear face of the slow loris (Nycticebus sp.) has made them a target for illegal pet poachers throughout the animal's range in southeastern Asia and nearby islands. A University of Missouri doctoral student and her colleagues recently identified three new species of slow loris. The primates had originally been grouped with another species. Dividing the species into four distinct classes means the risk of extinction is greater than previously believed for the animals but could help efforts to protect the unusual primate.

"Four separate species are harder to protect than one, since each species needs to maintain its population numbers and have sufficient forest habitat," said lead author Rachel Munds, MU doctoral student in anthropology in the College of Arts and Science. "Unfortunately, in addition to habitat loss to deforestation, there is a booming black market demand for the animals. They are sold as pets, used as props for tourist photos or dismembered for use in traditional Asian medicines."

According to Munds, slow lorises are not domesticated and are protected under the Convention on International Trade in Endangered Species. She contends that keeping the animals as pets is cruel and that domesticating them is not feasible.

"Even zoos have difficulty meeting their nutritional needs for certain insects, tree gums and nectars," said Munds. "Zoos rarely succeed in breeding them. Nearly all the primates in the pet trade are taken from the wild, breaking the bonds of the lorises' complex and poorly understood social structures. The teeth they use for their venomous bite are then torn out. Many of them die in the squalid conditions of pet markets. Once in the home, pet keepers don't provide the primates with the social, nutritional and habitat requirements they need to live comfortably. Pet keepers also want to play with the nocturnal animals during the day, disrupting their sleep patterns."

The newly identified species hail from the Indonesian island of Borneo. Munds and her colleagues observed that the original single species contained animals with significantly different body sizes, fur thickness, habitats and facial markings. Museum specimens, photographs and live animals helped primatologists parse out four species from the original one. Now instead of one animal listed as vulnerable by the International Union for the Conservation of Nature, there may be four endangered or threatened species. This potential change in conservation status may serve to draw attention the plight of the primates and increase legal protections.

"YouTube videos of lorises being tickled, holding umbrellas or eating with forks have become wildly popular," said Anna Nekaris, study co-author, primatology professor at Oxford Brookes University and MU graduate. "CNN recently promoted loris videos as 'feel good' entertainment. In truth, the lorises gripping forks or umbrellas were simply desperate to hold something. The arboreal animals are adapted to spending their lives in trees constantly clutching branches. Pet keepers rarely provide enough climbing structures for them."

The pet trade isn't the only threat to loris survival. The animals also are used in Asian traditional medicines. The methods used to extract the medicines can be exceedingly violent, according to Nekaris, who also is director of the slow loris advocacy organization, Little Fireface Project. For example, in order to obtain tears of the big-eyed lorises, skewers are inserted into the animals' anuses and run through their bodies until they exit the mouth. The still-living animals are then roasted over a smoky fire and the tears that stream from their eyes are collected and used to supposedly treat eye diseases in humans.

A video about the illegal trade in slow lorises can be viewed here: Tickling Slow Loris -- The Truth (http://www.youtube.com/watch?v=RF9-Dp3unTU).

"Taxonomy of the Bornean Slow Loris, with New Species Nycticebus Kayan," was published in the American Journal of Primatology. The paper described the physiological and habitat differences that justified dividing the three new species of slow loris (N. bancanus, N. borneanus and N. kayan) from the original species of slow loris N. menagensis.Susan Ford of Southern Illinois University also was co-author.

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Journal Reference:

R. Munds, S. Ford, K.A.I. Nekaris. Taxonomy of the Bornean Slow Loris, with New Species Nycticbus Kayan (Priamtes Lorisdae). American Journal of Primatology, December 2012; DOI: 10.1002/22071

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Dogs can accurately sniff out 'superbug' infections

Dec. 13, 2012 — Dogs can sniff out Clostridium difficile (the infective agent that is responsible for many of the dreaded "hospital acquired infections") in stool samples and even in the air surrounding patients in hospital with a very high degree of accuracy, finds a study in the Christmas issue published on bmj.com today.

The findings support previous studies of dogs detecting various types of cancer and could have great potential for screening hospital wards to help prevent C. difficile outbreaks, say the researchers.

C. difficile infection most commonly occurs in older people who have recently had a course of antibiotics in hospital, but it can also start in the community, especially in care homes. Symptoms can range from mild diarrhoea to a life-threatening inflammation of the bowel.

Early detection is vital to prevent transmission, but diagnostic tests can be expensive and slow, which can delay treatment for up to a week.

Diarrhoea due to C. difficile has a specific smell, and dogs have a superior sense of smell compared with humans. This prompted researchers in the Netherlands to investigate whether a dog could be trained to detect C. difficile.

A two-year old male beagle (called Cliff) was trained by a professional instructor to identify C. difficile in stool samples and in patients with C. difficile infection. He was taught to indicate the presence of the specific scent by sitting or lying down.

The dog had not been trained for detection purposes before.

After two months of training, the dog's detection abilities were formally tested on 50 C. difficile positive and 50 C. difficile negative stool samples. He correctly identified all 50 positive samples and 47 out of 50 negative samples.

This equates to 100% sensitivity and 94% specificity (sensitivity measures the proportion of positives correctly identified, while specificity measures the proportion of negatives correctly identified).

The dog was then taken onto two hospital wards to test his detection abilities in patients. He correctly identified 25 out of 30 cases (sensitivity 83%) and 265 out of 270 negative controls (specificity 98%).

The researchers add that the dog was quick and efficient, screening a complete hospital ward for the presence of patients with C. difficile infection in less than 10 minutes.

They point to some study limitations, such as the unpredictability of using an animal as a diagnostic tool and the potential for spreading infections via the dog, and say some unanswered questions remain.

However, they say their study demonstrates that a detection dog can be trained to identify C. difficile infection with a high degree of accuracy, both in stool samples and in hospitalised patients. "This could have great potential for C. difficile infection screening in healthcare facilities and thus contribute to C. difficile infection outbreak control and prevention," they conclude.

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The above story is reprinted from materials provided by BMJ-British Medical Journal.

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Journal Reference:

M. K. Bomers, M. A. van Agtmael, H. Luik, M. C. van Veen, C. M. J. E. Vandenbroucke-Grauls, Y. M. Smulders. Using a dog's superior olfactory sensitivity to identify Clostridium difficile in stools and patients: proof of principle study. BMJ, 2012; 345 (dec13 8): e7396 DOI: 10.1136/bmj.e7396

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Dolphin hearing system component found in insects

Dec. 13, 2012 — A hearing system component thought to be unique in toothed whales like dolphins has been discovered in insects, following research involving the University of Strathclyde.

The research is challenging ideas about how a large group of insects including crickets and katydids hear, revealing the unexpected similarity to toothed whale hearing.

Scientists from the School of Biological Sciences at The University of Auckland, with colleagues from Plant & Food Research in New Zealand, led the research with engineers from the University of Strathclyde working on the biomechanical aspects of the project.

They discovered that the iconic New Zealand insect, the weta, rely on a unique lipid -- a compound that includes oils and fats -- to hear the world around them.

Dr James Windmill, of the University of Strathclyde's Centre for Ultrasonic Engineering, said: "As engineers we are particularly interested in how sound interacts with certain materials and how it travels to and from a source. These findings help us to improve our fundamental knowledge and could inspire new systems in ultrasound technologies like biomedical and non-destructive testing.

"The discovery is interesting as previously only toothed whales were known to use this hearing system component, the lipid. There are many similarities in the use of lipids to amplify the sounds and help both animal groups to hear.

"We don't know why animals who are so far apart in evolutionary terms have this similarity, but it opens up the possibility that others may use the same system component."

The sound is known to be transmitted through a liquid-filled cavity to reach the hearing organs, but until the current research was carried out it was presumed that the liquid was simply the insect equivalent of blood.

The researchers found that it was in fact a lipid of a new chemical class. They believe the role of the lipid is to efficiently transmit sound between compartments of the ear, and perhaps to help amplify quiet sounds.

Dr Kate Lomas from the University of Auckland, said: "In the weta, as in other members of the Ensiferan group which includes katydids and crickets, sound is detected by ear drums on the front legs."

Using new tissue analysis and three-dimensional imaging techniques the scientists also discovered a tiny organ in the insects' ears, which they named the olivarius after Dr Lomas' son Ollie. The organ appears to be responsible for producing the all-important lipid. It may have been overlooked in previous studies because standard analytical techniques, which are much harsher, would have damaged or destroyed the fragile tissue.

Dr Lomas added: "The ear is surprisingly delicate so we had to modify how we looked at its structure and in doing so we discovered this tiny organ."

The researchers carried out their work with the Auckland tree weta. They believe that the same method of hearing is likely to be used by other members of its biologic class, including crickets and katydids, which are famous for the sounds they produce.

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Journal Reference:

Kathryn F. Lomas, David R. Greenwood, James FC. Windmill, Joseph C. Jackson, Jeremy Corfield, Stuart Parsons. Discovery of a Lipid Synthesising Organ in the Auditory System of an Insect. PLoS ONE, 2012; 7 (12): e51486 DOI: 10.1371/journal.pone.0051486

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Synthetic biology research: Could fuel for cars or household power supplies be created from naturally-occurring fatty acids?

Dec. 17, 2012 — Writing in PNAS, the researchers have shown that the emerging field of synthetic biology can be used to manipulate hydrocarbon chemicals, found in soaps and shampoos, in cells.

This development, discovered with colleagues at the University of Turku in Finland, could mean fuel for cars or household power supplies could be created from naturally-occurring fatty acids.

The researchers, led by Professor Nick Turner from The University of Manchester, used synthetic biology to hijack the naturally-existing fatty acids and direct those fatty molecules towards the production of ready-to-use fuel and household chemicals.

Hydrocarbon chemicals are everywhere in our daily lives; as fragrance in soap, thickener in shampoo and fuel in the car. Their number of carbons and whether they are acid, aldehyde, alcohol or alkane are important parameters that influence how toxic they are to biological organisms, the potential for fuel and their olfactory perception as aroma compounds.

The breakthrough allows researchers to further explore how to create renewable energy from sustainable sources, and the advance could lead to more innovative ways of sourcing fuel from natural resources.

Synthetic biology is an area of biological research and technology that combines science and engineering for the benefit of society. Significant advances have been made in this field in recent years.

Professor Turner said: "In our laboratories in Manchester we currently work with many different biocatalysts that catalyse a range of chemical reactions -- the key is to match up the correct biocatalyst with the specific product you are trying to make.

"Biocatalysts recognise molecules in the way that a lock recognises a key -- they have to fit perfectly together to work. Sometime we redesign the lock so that if can accept a slightly different key allowing us to make even more interesting products.

"In this example we need to make sure that the fatty acid starting materials would be a perfect match for the biocatalysts that we discovered and developed in our laboratories.

"As with many leading areas of science today, in order to make major breakthroughs it is necessary for two or more laboratories around the world to come together to solve challenging problems."

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The above story is reprinted from materials provided by University of Manchester, via EurekAlert!, a service of AAAS.

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Journal Reference:

M. Kalim Akhtar, Nicholas J. Turner, and Patrik R. Jones. Carboxylic acid reductase is a versatile enzyme for the conversion of fatty acids into fuels and chemical commodities. PNAS, December 17, 2012 DOI: 10.1073/pnas.1216516110

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Secrets of gentle touch revealed

Dec. 9, 2012 — Stroke the soft body of a newborn fruit fly larva ever-so-gently with a freshly plucked eyelash, and it will respond to the tickle by altering its movement -- an observation that has helped scientists at the University of California, San Francisco (UCSF) uncover the molecular basis of gentle touch, one of the most fundamental but least well understood of our senses.

Our ability to sense gentle touch is known to develop early and to remain ever-present in our lives, from the first loving caresses our mothers lavish on us as newborns to the fading tingle we feel as our lives slip away. But until now, scientists have not known exactly how humans and other organisms perceive such sensations.

In an article published online this week in the journal Nature, the UCSF team has identified the exact subset of nerve cells responsible for communicating gentle touch to the brains of Drosophila larvae -- called class III neurons. They also uncovered a particular protein called NOMPC, which is found abundantly at the spiky ends of the nerves and appears to be critical for sensing gentle touch in flies.

Without this key molecule, the team discovered, flies are insensitive to any amount of eyelash stroking, and if NOMPC is inserted into neurons that cannot sense gentle touch, those neurons gain the ability to do so.

"NOMPC is sufficient to confer sensitivity to gentle touch," said Yuh Nung Jan, PhD, a professor of physiology, biochemistry and biophysics and a Howard Hughes Medical Institute investigator at UCSF. Jan led the study with his wife Lily Jan, PhD, who is also a UCSF professor and a Howard Hughes Medical Institute investigator.

The work sheds light on a poorly understood yet fundamental sense through which humans experience the world and derive pleasure and comfort.

Jan added that while the new work reveals much, many unanswered questions remain, including the exact mechanism through which NOMPC detects mechanical force and the identity of the analogous human molecules that confer gentle touch sensitivity in people.

The discovery is a good example of basic brain research paving the way toward answering such questions. UCSF is a world leader in the neurosciences, carrying out research that spans the spectrum from fundamental questions of how the brain works to the clinical development of new drugs and precision tools to address brain diseases; educating the next generation of neuroscientists, neurologists and neurosurgeons; and offering excellent patient care for neurological diseases.

Why is Touch Still Such a Mystery?

Though it is fundamental to our experience of the world, our sense of gentle touch has been the least well understood of our senses scientifically, because, unlike with vision or taste, scientists have not known the identity of the molecules that mediate it.

Scientists generally feel that, like those other senses, the sense of touch is governed by peripheral nerve fibers stretching from the spine to nerve endings all over the body. Special molecules in these nerve endings detect the mechanical movement of the skin surrounding them when it is touched, and they respond by opening and allowing ions to rush in. The nerve cell registers this response, and if the signal is strong enough, it will fire, signaling the gentle touch to the brain.

What has been missing from the picture, however, are the details of this process. The new finding is a milestone in that it defines the exact nerves and uncovers the identity of the NOMPC channel, one of the major molecular players involved -- at least in flies.

Jan and his colleagues made this discovery through an unusual route. They were looking at the basic physiology of the developing fruit fly, examining how class III neurons develop in larvae. They noticed that when these cells developed in the insects, their nerve endings would always become branches into spiky "dendrites."

Wanting to know what these neurons are responsible for, they examined them closely and found the protein NOMPC was abundant at the spiky ends. They then examined a fly genetically engineered to have a non-functioning form of NOMPC and showed that it was insensitive to gentle touch. They also showed that they could induce touch sensitivity in neurons that do not normally respond to gentle touch by inserting copies of the NOMPC protein into them.

This work was funded by the National Institutes of Health via grant #R37NS040929 and #5R01MH084234; by the Howard Hughes Medical Institute; and through two Long-Term Fellowships from the Human Frontier Science Program.

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The above story is reprinted from materials provided by University of California, San Francisco (UCSF), via Newswise.

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Journal Reference:

Zhiqiang Yan, Wei Zhang, Ye He, David Gorczyca, Yang Xiang, Li E. Cheng, Shan Meltzer, Lily Yeh Jan, Yuh Nung Jan. Drosophila NOMPC is a mechanotransduction channel subunit for gentle-touch sensation. Nature, 2012; DOI: 10.1038/nature11685

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