by Michael Le Page No one would believe that bacteria caused stomach ulcers – until Barry Marshall swallowed some BACK in 1984, a young Australian doctor called Barry Marshall swallowed a nasty-tasting solution of bacteria. This was no accident. He did it to convince his peers that his suspicions about a highly prevalent disease were not as far-fetched as they thought. In 1981, Marshall had met pathologist Robin Warren, who had found curved bacteria in inflamed stomach tissue. In further studies, they found that this bacterium, later named Helicobacter pylori, was present in most people who had inflammation or ulcers of the stomach or gut. Like two long-forgotten German researchers in 1875, they concluded that these bacteria were to blame. "I was met with constant criticism that my conclusions were premature," Marshall later wrote. "My results were disputed and disbelieved, not on the basis of science but because they simply could not be true." It is often claimed that doctors were wedded to the idea that ulcers were caused by excess stomach acid, or that they didn't believe that bacteria could grow in the stomach. In fact, the main reason for the scepticism, says Richard Harvey of the Frenchay Hospital in Bristol, UK, was that four-fifths of ulcers were not in the stomach but further down the digestive tract. © Copyright Reed Business Information Ltd.

Keyword: Stress
Link ID: 14467 - Posted: 09.20.2010

By Steve Connor The scourge of premenstrual tension, which affects more than half of women and causes physical as well as emotional trauma, could soon be eradicated by a safe, low-dose pill, scientists said yesterday. A laboratory-based study has found that very low doses of the anti-depression drug Prozac can eliminate the symptoms of premenstrual syndrome, which include mood swings, tiredness, irritability, headaches and joint pains. The scientist leading the research said the findings, which have so far been observed in laboratory rats, are strong enough to warrant a full-scale clinical trial with Prozac given that the drug has already undergone the necessary safety tests at the higher doses needed to treat depression. A clinical trial could begin within six months, and if the results are favourable, women could be taking the drug to treat premenstrual syndrome within two years, said Thelma Lovick, a neuroscientist at the University of Birmingham, who led the study. Not all women have the monthly symptoms associated with their menstrual cycle, but it is estimated that 75 per cent have experienced them at some time and that between 30 and 40 per cent have more severe symptoms that badly affect their work and family lives. The three-year study, funded by the Medical Research Council, has shown that Prozac taken in doses of about a tenth of that needed to treat depression can stop premenstrual symptoms in rats, animals which show physical and emotional changes, such as increased anxiety and sensitivity to pain, similar to those seen in women. Higher doses of Prozac have been prescribed to women suffering from premenstrual syndrome in the past, especially by doctors in the US, but usually for the treatment of more severe symptoms such as depression. ©independent.co.uk

Keyword: Depression; Hormones & Behavior
Link ID: 14466 - Posted: 09.18.2010

By Katherine Harmon When answering a question, your accuracy in assessing whether you have gotten the answer right—or wrong—might depend on the volume of gray matter in a certain part of your brain, according to a new study. Introspection—or metacognition, self-awareness about one's thinking—is a high-level mental process. "Accurate introspection requires discriminating correct decisions from incorrect ones, a capacity that varies substantially across individuals," researchers behind the new findings explained in their study. For the study, researchers used simple visual stimuli to test 32 healthy subjects' perception—and how confident they felt about their assessment of a geometric image. The tests were customized to each individual's level of perceptual skill, in order to keep each subject's accuracy score at 71 percent, so that the test was consistently difficult for all subjects. "Someone who has good introspective ability will accurately be able to know" if they were correct in their assessment of an image, explains Steven Fleming, a cognitive neuroscientist at the Wellcome Trust Centre for Neuroimaging at University College London and co-author of the new study. The study team found "considerable variation" in subjects' accuracy in assessing their own evaluations of the images, which was to be expected based on previous research. Fleming and his colleagues used magnetic resonance imaging (MRI) to evaluate the subjects' whole brains for differences in structure and composition in order to look for correlations with introspective ability. © 2010 Scientific American,

Keyword: Attention
Link ID: 14465 - Posted: 09.18.2010

by Roger Highfield Before winning his Nobel prize, Stanley Prusiner was ridiculed for suggesting that something he called a prion caused spongiform brain diseases WHEN the evidence suggested that the baffling "spongiform" brain disorders Creutzfeldt-Jakob disease (CJD), kuru and scrapie could not be transmitted by a virus or bacterium, the neurologist Stanley Prusiner put forward a novel type of infectious agent as the cause: a rogue protein. It was an idea considered so outrageous that Prusiner was ridiculed. Prusiner first began to study these diseases in 1972, after one of his patients at the University of California, San Francisco, died of CJD. A decade later, in the journal Science (vol 216, p 136), he suggested that these diseases were caused by a "proteinaceous infectious particle", or prion. The idea built on the findings of British researchers. In 1967, Tikvah Alper of the Medical Research Council's Radiopathology Unit showed that whatever it was that caused CJD was unscathed by levels of ultraviolet radiation that would destroy any genetic material (Nature, vol 214, p 764). Shortly afterwards, mathematician John Stanley Griffith of Bedford College in London devised a protein-only hypothesis for scrapie propagation. His 1967 Nature paper (vol 215, p 1043) states there was no reason to fear that the idea "would cause the whole theoretical structure of molecular biology to come tumbling down". © Copyright Reed Business Information Ltd.

Keyword: Prions
Link ID: 14464 - Posted: 09.18.2010

By Gwyneth Dickey Scientists have uncovered a new chemical process that may explain how antidepressants like Prozac work. The newly found mechanism also suggests why the drugs take weeks to start helping and may one day point to new therapies for depression. A team from Paris has found that fluoxetine, commonly known as Prozac, increases the amount of a particular microRNA called miR-16 in the brain. A microRNA is a small piece of RNA that prevents the translation of messenger RNA into protein. The miR-16 microRNA slows the formation of a cleaner-upper protein called the serotonin transporter. The protein clears away serotonin, a chemical that helps brain cells communicate and alleviates depression, from the space between brain cells. With less of the cleaner-upper to gobble up serotonin in the brain, there’s more serotonin in the spaces between brain cells, and depression symptoms lessen for some patients. The results are published in the Sept. 17 Science. “It’s an exciting development,” says pharmacologist Alan Frazer of the University of Texas Health Science Center at San Antonio. “As far as I know, it’s the first demonstration of a microRNA able to affect serotonin transporter expression.” Scientists knew that Prozac and other drugs like it, called selective serotonin reuptake inhibitors or SSRIs, somehow blocked the action of the serotonin transporter and left more serotonin in the brain. But exactly how the drugs worked, and why they took so long to have an effect, was a mystery. © Society for Science & the Public 2000 - 2010

Keyword: Depression
Link ID: 14463 - Posted: 09.18.2010

Men with low levels of stress are more attractive to women, according to research at the University of Abertay. The team analysed hormone levels in young men and showed pictures to a group of women. It found a strong link between low levels of the stress hormone cortisol in men and how attractive they were to the opposite sex. The research also discovered no link between high levels of the sex hormone testosterone and sex appeal. Dr Fhionna Moore, a psychology lecturer at Abertay University who lead the research team, said that previous studies had suggested a link between high levels of testosterone and greater health benefits as it was thought that only males with a strong immune system could cope with higher levels of the sex hormone. She said the university's study debunked that suggestion saying: "We analysed different levels and combinations of cortisol and testosterone and found a strong link between low cortisol levels, which is present when someone has low stress levels, and being highly attractive to women." The study also showed that female attraction to men with low stress levels was at its highest during the fertile phase of their cycle. (C)BBC

Keyword: Sexual Behavior; Stress
Link ID: 14462 - Posted: 09.16.2010

A small number of autism cases are linked to a gene found on the X chromosome, a discovery that may help explain why boys are four times more likely than girls to develop the disorder. There is no one gene responsible for autism spectrum disorder, or ASD. People with the disorder may have mild to severe symptoms that inhibit a person's ability to communicate and develop social relationships, which is often accompanied by behavioural challenges. In some people the disorder has a strong inherited component. Now, in Wednesday's online issue of the journal Science Translational Medicine, researchers at Toronto's Hospital for Sick Children, the Centre for Addiction and Mental Health and others report specific genetic alterations on the X chromosome that increase the risk of developing autism. Females carry two copies of the X chromosome, so they have a backup. Males, however, have only one X from their mothers and one Y from their fathers. So males who would inherit the genetic change from their mother are not protected, said the study's co-senior author, Prof. Stephen Scherer, senior scientist and director of the Centre for Applied Genomics at Sick Kids. About one in 70 baby boys will develop ASD, Scherer said in an interview. "So we've now identified the genetic cause in one per cent of those individuals, so in fact it's actually a large proportion of the population," Scherer said, meaning this newly identified mutation likely accounts for the biggest proportion of genes associated with autism. © CBC 2010

Keyword: Autism; Genes & Behavior
Link ID: 14461 - Posted: 09.16.2010

Characterized by paranoia, anxiety, hallucinations and delusions, schizophrenia and schizoaffective disorder, a related condition, are complicated mental illnesses that make it difficult for one to determine the difference between reality and pretend. While there are medications and therapies that can help, the effects of this condition are often far- reaching. Here, seven men and women speak about living with schizophrenia or schizoaffective disorder. Copyright 2010 The New York Times Company

Keyword: Schizophrenia
Link ID: 14460 - Posted: 09.16.2010

By Gary Stix What is a fate as bad as death? Many contemporary and ancient societies considered banishment at least equal. After all, in the past, estrangement from family or friends, along with the corresponding exile away from the campfire or town gates, meant literally getting thrown to the wolves. Not surprisingly, our brains are wired with circuitry so that we can scrupulously avoid such fates, whether that means expulsion to the desert as in the Biblical tale of Hagar and Ishmael or the heartbreak of not getting that long-awaited invitation to the high school prom. The neurological wiring that makes us feel pain, new research suggests, also means that a common painkiller could ease the sting. One brain area in question resides about an inch behind your forehead. Called the anterior cingulate cortex, it serves as one of the brain’s control centers for that “why me?” feeling when you get picked last for the dodgeball game. It also happens to be the same circuitry that induces the emotional component of pain, that desperate feeling provoked by the throbbing of a toothache. Evolution may have piggybacked brain functions that regulate social interaction on top of a more primal pain system. The way we speak (“I’m crushed”) even hints at just such a connection. Research from the 1970s in rodents on the overlapping functions of this brain circuitry showed that opiates tended to quell not only painful stimuli but also the tiny squeaks that signal distress. C. Nathan DeWall, a social psychologist at the University of Kentucky who has researched the neurobiology of rejection for nearly 10 years, wondered whether an extraordinarily simple step to tone down these double-duty pain circuits might work in the human brain, which has evolved to master playground politics and other complex behaviors. Instead of dosing subjects with Vicodin, he and colleagues simply handed out acetaminophen (Tylenol) or a placebo to 62 volunteers. “We didn’t have to use fancy drugs; we didn’t have to get prescriptions,” he says. © 2010 Scientific American, a division of Nature America,

Keyword: Pain & Touch; Emotions
Link ID: 14459 - Posted: 09.16.2010

By Jesse Bering There are signs, some would say omens, glimmering in certain children’s demeanors that, probably ever since there were children, have caused parents’ brows to crinkle with worry, precipitated forced conversations with nosy mothers-in-laws, strained marriages and ushered untold numbers into the deep covenant of sexual denial. We all know the stereotypes: an unusually light, delicate, effeminate air in a little boy’s step, often coupled with solitary bookishness, or a limp wrist, an interest in dolls, makeup, princesses, dresses and a staunch distaste for rough play with other boys; in little girls, there is the outwardly boyish stance, perhaps a penchant for tools, a lumbering gait, a square-jawed readiness for physical tussles with boys, an aversion to all the perfumed, delicate, laced trappings of femininity. So let’s get down to brass tacks. It’s what these behaviors signal to parents about their child’s incipient sexuality that makes them so undesirable—these behavioral patterns are feared, loathed and often spoken of directly as harbingers of adult homosexuality. However, it is only relatively recently that developmental scientists have conducted controlled studies with one clear aim in mind, which is to go beyond mere stereotypes and accurately identity the most reliable signs of later homosexuality. In looking carefully at the childhoods of now-gay adults, researchers are finding an intriguing set of early behavioral indicators that homosexuals seem to have in common. And, curiously enough, the age-old homophobic fears of parents seem to have some genuine predictive currency. © 2010 Scientific American, a division of Nature America,

Keyword: Sexual Behavior; Development of the Brain
Link ID: 14458 - Posted: 09.16.2010

By Tina Hesman Saey Chemical modifications to DNA may affect the activity of key genes involved in regulating body weight, a study finds, raising the possibility that scientists could discover environmental factors beyond calorie intake and exercise that influence a person’s size. The study, published September 15 in Science Translational Medicine, is also the first to demonstrate that these chemical modifications to DNA are unique to an individual and may affect a person’s risk of developing common diseases. Referred to as epigenetic, these changes don’t alter the DNA sequence itself but the way genes are turned on and off. Studying epigenetic marks may help scientists learn more about the causes of disease, says Michael Skinner, an epigenetics researcher at Washington State University in Pullman who was not part of the new study. “There’s a great deal of disease that is directly influenced by the environment that today we can’t explain just using genetics,” he says. In the study, researchers from Johns Hopkins University mapped one type of epigenetic change known as methylation in DNA samples taken 11 years apart from 74 Icelandic people. Methylation generally has the effect of turning off nearby genes. The team surveyed about 4.5 million spots on the genome of each person and determined how much of the DNA at each location carried marks of methylation. The amount of methylation varied among people at 227 of those spots, dubbed variably methylated regions or VMRs. Each person had a unique combination of these regions. © Society for Science & the Public 2000 - 2010

Keyword: Obesity; Genes & Behavior
Link ID: 14457 - Posted: 09.16.2010

by Andy Coghlan THE first trial of a drug intended to rebalance the brain chemistry of people with autism has helped symptoms in most of the 25 volunteers who tested it - with reductions in irritability and tantrums, and improvements in social skills. The announcement coincides with news that the US federal government has finalised its financial package for Hannah Poling. In 2008 the government concluded that vaccinations may have resulted in her autism-like symptoms. The family will receive $1.5 million, plus $500,000 annually to cover the costs of caring for her. Her case, however, is likely to be unique - she has a rare underlying genetic condition affecting her mitochondria, the powerhouses of the cell. This was judged to account for the symptoms she developed after vaccination. As the debate over vaccination and autism rumbles on in the US, the results from the drug trial of arbaclofen are encouraging. Although doctors sometimes prescribe drugs for autism, they are usually antidepressants and anti-psychotics and aimed at specific symptoms. Arbaclofen, by contrast, is intended to rebalance brain chemistry, said to be awry in people with autism spectrum disorders. "We are trying to normalise signalling functions within the brain," says Randall Carpenter of Seaside Therapeutics in Cambridge, Massachusetts. The firm is developing arbaclofen as a generic under the name STX209. © Copyright Reed Business Information Ltd.

Keyword: Autism
Link ID: 14456 - Posted: 09.16.2010

Oliver Sacks As a physician, I am concerned with people who have neurological damage or disease or who are, in general, trying to improve their neurological function. Something that has intrigued me recently is how, after one has lost one’s eyesight, the mind’s eye—the brain’s ability to create visual images—not only persists but can be heightened and harnessed. A lot of people who lose their sight are still visual people. As they read braille with their fingertips, they may experience it visually. This is not just a metaphor or a manner of speaking; functional imagery of their visual cortex shows that it is activated as they read braille. It’s a cross-modal transfer, so that touch is converted into visual experience in the brain. The term for this is sensory substitution, a concept originally introduced by an extraordinary man, the neuroscientist Paul Bach-y-Rita. He wondered whether, by using a video camera and connecting it up pixel for pixel to an area on the skin, one could form a mental picture based on tactile impulses felt by the skin. He tried the tongue, which has the finest sensory discrimination in the body. With such a device, a blind person can form a picture of the environment sufficiently detailed, for example, to catch a ball that is rolled toward him. But this is by no means the limit. One could have much higher discrimination, giving one a sense comparable to not-bad vision. What is extraordinary is that even though it’s the tongue that is stimulated, people using such devices maintain they are getting a visual picture of the world. Sensory substitution can take other forms, and one has to wonder, in terms of future technology, whether this ability to use other senses could be refined.

Keyword: Learning & Memory
Link ID: 14455 - Posted: 09.16.2010

By TARA PARKER-POPE During basketball practice last year, 12-year-old Nicole Dehart was shooting the ball when a defender tried aggressively to block her shot. The two players made contact, and Nicole hit the floor headfirst. “The way she was hit took her whole body out from under her, and she landed directly on her head,” said her mother, Christine White, of Pataskala, Ohio. “We immediately knew this was serious. She was very confused and looking at people like she didn’t know who they were.” At the hospital, doctors diagnosed a concussion —an increasingly common injury in youth basketball, particularly among girls, yet one that has yet to gain widespread attention. In fact, Ms. White said, she knew enough to worry about concussions — but when Nicole played soccer, not basketball. “I worried more about broken bones, being that it is a hard floor,” she said. “But the physical contact of basketball is a lot like football inside.” On Monday, the medical journal Pediatrics reported that about 375,000 children and teenagers are treated in hospital emergency rooms each year for basketball-related injuries. Notably, the proportion related to head trauma is on the rise. In 2007, the last year of the study, about 4 percent of youth basketball injuries were to the head, about double the number of such injuries reported by emergency rooms in 1997. Copyright 2010 The New York Times Company

Keyword: Brain Injury/Concussion
Link ID: 14454 - Posted: 09.14.2010

By RONI CARYN RABIN Men develop mild cognitive impairment, often a precursor to Alzheimer’s disease, earlier and at higher rates than women, according to a new study of almost 2,000 people in their 70s and 80s. The difference is surprising, since dementia and Alzheimer’s are thought to affect more women than men, said the paper’s lead author, Dr. Ronald C. Petersen, director of the Mayo Alzheimer’s Disease Research Center. People with mild cognitive impairment appear to be functioning normally, but their forgetfulness is beyond what occurs in normal aging. To determine the condition’s prevalence, Mayo researchers conducted extensive neurological examinations of 1,969 randomly selected 70-to-89-year-olds in residents of Olmsted County, Minn. Nineteen percent of the men had mild cognitive impairment, compared with 14 percent of the women. (The percentages do not include those with full-blown dementia, which afflicts roughly 10 percent in this age group.) The study, financed by the National Institute on Aging, was published in the journal Neurology. Besides men in general, subjects found to be at higher risk for mild cognitive impairment included those who had never been married, those with less than nine years of schooling and those carrying the ApoE4 gene, which is a risk factor for late-onset Alzheimer’s. Copyright 2010 The New York Times Company

Keyword: Alzheimers; Sexual Behavior
Link ID: 14453 - Posted: 09.14.2010

By NICHOLAS WADE Under Mendel’s laws of inheritance, you could thank mom and dad equally for all the outstanding qualities you inherited. But there’s long been some fine print suggesting that a mother’s and father’s genes do not play exactly equal roles. Research published last month now suggests the asymmetry could be far more substantial than supposed. The asymmetry, based on a genetic mechanism called imprinting, could account for some of the differences between male and female brains and for differences in a mother’s and father’s contributions to social behavior. A person gets one set of genes from each parent. Apart from the sex chromosomes, the two sets are equivalent, and in principle it should not matter if a gene comes from mother or father. The first sign that this is not always true came from experiments in which mouse embryos were engineered to carry two male genomes, or two female genomes. The double male and double female mice all died in the womb. Nature evidently requires one genome from each parent. Biologists then made the embryos viable by mixing in some normal cells. The surprising outcome was that mice with two male genomes had large bodies and small brains. With the double female genome mice, it was the other way around. Evidently the maternal and paternal genomes have opposite effects on the size of the brain. The root of the asymmetry is a procedure called imprinting in which either the mother’s or the father’s copy of a particular gene is inactivated. The best worked out example concerns a gene called insulinlike growth factor-2, which promotes the growth of the fetus. The IGF-2 gene is active in the paternal genome but imprinted or inactivated in the genome the fetus receives from its mother. Copyright 2010 The New York Times Company

Keyword: Sexual Behavior; Development of the Brain
Link ID: 14452 - Posted: 09.14.2010

By Emily Sohn Sugar is the enemy, according to a growing body of research, and not just because it rots our teeth and adds padding to our thighs. The real danger is fructose -- a main ingredient in table sugar, high fructose corn syrup, and fruit -- that actually gets into our cells and alters metabolism. The findings may help to explain how our nation's excessive consumption of sweetened foods is contributing to growing rates of obesity, heart disease, high blood pressure, diabetes and more -- in a way that has nothing to do with sugar's rich source of empty calories. What's more, there may be deep evolutionary roots that explain sugar's power over our bodies. Many millions of years ago, according to new research, our ape ancestors developed mutations that made it easy for them to get fat from eating fructose. At the time, the mutation was a good thing. It allowed our ancestors to survive seasonal periods of famine when the fruit trees went bare. Today, the mutation makes a year-round, fructose-filled diet dangerous to our health, said Richard Johnson, chief of the division of Renal Diseases and Hypertension at the University of Colorado, Denver, and author of "The Sugar Fix: The High-Fructose Fallout That Is Making You Fat and Sick." Both sugar and high-fructose corn syrup are equally bad, he said, because both contain about the same amount of fructose. © 2010 Discovery Communications, LLC.

Keyword: Obesity; Evolution
Link ID: 14451 - Posted: 09.14.2010

by Ann Gibbons The faster a baby boy gains weight in the first 6 months of life, the more sex he'll probably have as a young adult. That's one of the startling new findings of a long-term study of more than 700 men from birth to early adulthood in the Philippines. The fastest-growing baby boys reached puberty earlier than babies who gained weight more slowly. By their early 20s, they were stronger, taller, and had more testosterone (and sex partners). "Your characteristics as an adult male—body size, lean mass, and sexual maturation—are programmed by your early experiences," says lead author Christopher Kuzawa, a biological anthropologist at Northwestern University in Chicago, Illinois. Researchers have long known that babies adapt to their world even before they're born—and that those adaptations affect their physiology and metabolism as adults, including their risk for chronic disease. Infants born to malnourished mothers, for example, are more likely to be born small and have efficient metabolisms that require less fuel to survive. Conversely, infants whose mothers were well-fed are often born larger and are more likely to grow bigger more rapidly, requiring more calories to maintain their larger bodies that can make them more attractive mates. Problems arise, however, when low-birth-weight babies are fed diets rich in sugars or fat, which stress their smaller organs, such as pancreases, for example, leading to diabetes—or when fast-growing children face famine. Scientists have debated whether these responses to good or bad times early in development are adaptive adjustments to their environment—reflecting that infants have a window of time early in life when they can fine-tune their developmental trajectories—or whether early deficiencies in nutrition and stress simply predispose these infants to more disease as adults. © 2010 American Association for the Advancement of Science.

Keyword: Sexual Behavior; Development of the Brain
Link ID: 14450 - Posted: 09.14.2010

Tim Kiladze A chief executive officer’s patience and co-operation can make or break a corporate merger or acquisition. That’s no secret. But researchers at the University of British Columbia’s Sauder School of Business now offer a biological explanation for male CEOs’ willingness, or lack thereof, to negotiate: testosterone levels. The UBC team crunched the numbers for 350 corporate deals completed between 1997 and 2007 and determined that the aggression-causing hormone directly affects a male CEO’s tendency to bid for a company – and to walk away from an unfavourable deal. “Normally, assets should go to buyers that value [them] the most,” finance professor and lead researcher Maurice Levi said, “if decisions are based purely on the basis of rationality.” However, his team found that hormones intervene and make CEOs bid for things they don’t necessarily need, or turn down offers out-of-hand, without trying to negotiate better terms. “They might be pursuing things that give them the most dominance, but do not give them the most value,” Mr. Levi said. Notably, men with higher testosterone levels are 20 per cent more likely to walk away from a takeover offer. They are also 4 per cent more likely to make takeover bids, a small effect but still statistically significant. The Sauder study was based on a 2007 Harvard University experiment in which pairs of male participants tried to make a deal to split $40. Participants with above-average testosterone levels, tested in a laboratory, were more likely to reject a lowball offer, whereas those with below-average levels were less likely to drive a hard bargain. © Copyright 2010 CTVglobemedia Publishing Inc.

Keyword: Hormones & Behavior; Aggression
Link ID: 14449 - Posted: 09.14.2010

Katharine Sanderson Artificial electronic skins that can detect the gentlest of touches have been developed by two independent US research groups. The skins could eventually be used in prosthetics, or in touch-sensitive robotic devices. Both systems detect pressure changes of less than a kilopascal, the same as everyday pressures felt by our fingers when typing or picking up a pen. This sensitivity is better than previous systems, which detected pressures of tens of kilopascals or more, or only detected static pressures so that once an object was sat on the skin, the device could not sense that it was still there. The devices, both reported in Nature Materials today, work in different ways1,2. Chemist Zhenan Bao at Stanford University, California, and her colleagues used the elastic polymer polydimethylsiloxane (PDMS)1. Bao took a piece of PDMS measuring six centimetres square with pyramid-shaped chunks cut out of it at regular intervals. When the PDMS is squashed, the pyramid-shaped holes that were previously filled with air become filled with PDMS, changing the device's capacitance, or its ability to hold an electric charge. An optical image of a fully fabricated e-skin device with nanowire active matrix circuitry. each dark square represents a single pixel.The use of pressure-sensitive rubber makes this artifical skin flexible.Ali Javey and Kuniharu Takei To make it easier to detect the changes in capacitance, Bao stuck the PDMS capacitor onto an organic transistor, which can read out the differences as a change in current. The team used a grid of transistors to track pressure changes at different points across the material. © 2010 Nature Publishing Group,

Keyword: Robotics; Pain & Touch
Link ID: 14448 - Posted: 09.13.2010