Breaking habits before they start

Breaking habits before they start

  7:57:00 AM    Science Lover

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Our daily routines can become so ingrained that we perform them automatically, such as taking the same route to work every day. Some behaviors, such as smoking or biting your fingernails, become so habitual that we can't stop even if we want to.

Although breaking habits can be hard, MIT neuroscientists have now shown that they can prevent them from taking root in the first place, in rats learning to run a maze to earn a reward. The researchers first demonstrated that activity in two distinct brain regions is necessary in order for habits to crystallize. Then, they were able to block habits from forming by interfering with activity in one of the brain regions—the infralimbic (IL) cortex, which is located in the prefrontal cortex.

The MIT researchers, led by Institute Professor Ann Graybiel, used a technique called optogenetics to block activity in the IL cortex. This allowed them to control cells of the IL cortex using light. When the cells were turned off during every maze training run, the rats still learned to run the maze correctly, but when the reward was made to taste bad, they stopped, showing that a habit had not formed. If it had, they would keep going back by habit.

"It's usually so difficult to break a habit," Graybiel says. "It's also difficult to have a habit not form when you get a reward for what you're doing. But with this manipulation, it's absolutely easy. You just turn the light on, and bingo."

Graybiel, a member of MIT's McGovern Institute for Brain Research, is the senior author of a paper describing the findings in the June 27 issue of the journal Neuron. Kyle Smith, a former MIT postdoc who is now an assistant professor at Dartmouth College, is the paper's lead author.

Patterns of habitual behavior

Previous studies of how habits are formed and controlled have implicated the IL cortex as well as the striatum, a part of the brain related to addiction and repetitive behavioral problems, as well as normal functions such as decision-making, planning and response to reward. It is believed that the motor patterns needed to execute a habitual behavior are stored in the striatum and its circuits.

Recent studies from Graybiel's lab have shown that disrupting activity in the IL cortex can block the expression of habits that have already been learned and stored in the striatum. Last year, Smith and Graybiel found that the IL cortex appears to decide which of two previously learned habits will be expressed.

"We have evidence that these two areas are important for habits, but they're not connected at all, and no one has much of an idea of what the cells are doing as a habit is formed, as the habit is lost, and as a new habit takes over," Smith says.

To investigate that, Smith recorded activity in cells of the IL cortex as rats learned to run a maze. He found activity patterns very similar to those that appear in the striatum during habit formation. Several years ago, Graybiel found that a distinctive "task-bracketing" pattern develops when habits are formed. This means that the cells are very active when the animal begins its run through the maze, are quiet during the run, and then fire up again when the task is finished.

This kind of pattern "chunks" habits into a large unit that the brain can simply turn on when the habitual behavior is triggered, without having to think about each individual action that goes into the habitual behavior.

The researchers found that this pattern took longer to appear in the IL cortex than in the striatum, and it was also less permanent. Unlike the pattern in the striatum, which remains stored even when a habit is broken, the IL cortex pattern appears and disappears as habits are formed and broken. This was the clue that the IL cortex, not the striatum, was tracking the development of the habit.

Multiple layers of control

The researchers' ability to optogenetically block the formation of new habits suggests that the IL cortex not only exerts real-time control over habits and compulsions, but is also needed for habits to form in the first place.

"The previous idea was that the habits were stored in the sensorimotor system and this cortical area was just selecting the habit to be expressed. Now we think it's a more fundamental contribution to habits, that the IL cortex is more actively making this happen," Smith says.

This arrangement offers multiple layers of control over habitual behavior, which could be advantageous in reining in automatic behavior, Graybiel says. It is also possible that the IL cortex is contributing specific pieces of the habitual behavior, in addition to exerting control over whether it occurs, according to the researchers. They are now trying to determine whether the IL cortex and the striatum are communicating with and influencing each other, or simply acting in parallel.

The study suggests a new way to look for abnormal activity that might cause disorders of repetitive behavior, Smith says. Now that the researchers have identified the neural signature of a normal habit, they can look for signs of habitual behavior that is learned too quickly or becomes too rigid. Finding such a signature could allow scientists to develop new ways to treat disorders of repetitive behavior by using deep brain stimulation, which uses electronic impulses delivered by a pacemaker to suppress abnormal brain activity.

Journal reference: Neuron

Provided by Massachusetts Institute of Technolog

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Apple patents 'anti-sexting' technology

Apple patents 'anti-sexting' technology

  9:06:00 PM    Science Lover

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Apple has patented technology that could be used by parents to prevent their kids from sending sexually explicit text messages -- or "sexting."

An Apple patent shows how an anti-sexting
application might block messages on the iPhone.

The technology, which has not been commercialized, would let a phone's administrator block an iPhone from sending or receiving texts with certain words.

Messages containing blocked material either would not be received or would have the objectionable content redacted. Unlike other text blockers, Apple's version would also be able to filter content based on a child's grade level and claims to filter abbreviated words that maybe missed by other programs.

The patent, awarded Tuesday, does not address the sending or receiving of explicit images.

The U.S. patent, which Apple filed for in January 2008, could also turn these filters into educational tools, according to the patent document.

Parents of kids who are studying Spanish, for example, could be required to send a certain number of messages per month in that language, according to the document. If kids did not meet the foreign language quota, their texting privileges could be automatically revoked until they send more Spanish-language text messages.

Grammarians may cheer this innovation. The texting interface also could prod kids toward better grammar, requiring them to identify and fix spelling, punctuation and grammar mistakes before sending a message.

So maybe the Apple texting tool will be the end of LOL-speak.

Apple says old methods of monitoring and controlling text communications on phones have largely failed. Allowing kids to communicate only with a pre-set list of phone numbers or e-mail addresses is limiting, the patent document says, and does not address the content of the mobile phone communications, which Apple says is more important.

Other methods of filtering only block certain expletives, Apple says, instead of trying to recognize the overall offensiveness of a message and comparing that to a kid's age and learning level.

The blog TechCrunch asks if the patent will be the end of sexting:

"Yes and no," Alexia Tsotsis writes on that blog, "as those interesting in 'sexting' will probably find some clever workaround to express how much they want to bang, screw, hit it or a myriad of other words that don't immediately set off the censorship sensors."

The Daily Mail in the UK writes that this anti-sexting news "will be music to the ears of Tiger Woods. Or Ashley Cole, or Vernon Kay for that matter," referring to sexting scandals involving those celebrities.

It's unclear exactly how this technology would be incorporated into Apple's iPhone products, but it would appear to work through the phone's built-in text-messaging application. Other texting apps aim to prevent texting while driving and let iPhone users send text messages without incurring charges from AT&T, the mobile carrier that has exclusive rights to the iPhone in the U.S.

Do you think this kind of technology will bring about the end of sexting and SMS slang? Let us know what you think in the comments below.

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Credit Card with a Computer Inside A smarter credit card could mean new security features and other functionality.

Credit Card with a Computer Inside A smarter credit card could mean new security features and other functionality.

  10:09:00 AM    Science Lover

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A programmable credit card can display useful information, offer added security features, and even act as several different cards by rewriting its own magnetic strip.

Smarter card: A user has to enter a PIN to display this
card’s full number and unlock its magnetic stripe for use
either online or in-store. After a short time the display
and magnetic stripe become blank again.
Credit: Dynamics

Two types of programmable credit cards were unveiled this week at the DEMO conference in Santa Clara, California, by Dynamics, a startup based in Pittsburgh that's been developing the technology in stealth mode for three years. The company raised $5.7 million of funding last year.

The new cards are no bigger than the one in your wallet, and is actually slightly more flexible. It can display information at the press of a button, and can become several different cards by rewriting its own magnetic strip.

The "MultiAccount" card has two buttons on its face, each with an indicator light that can be pressed to record data to its magnetic strip. "One might switch the card to be your debit card, and the other your credit card," says Dynamics CEO Jeff Mullen. "These cards are exactly the same size and thickness of a conventional card, and the lithium-polymer battery inside can last four years under high usage. They're also fully waterproof, so you can put them through the washing machine."

The "Hidden" card features a keypad and black-and-white display for six of the digits in the card's unique number. Once the correct PIN is entered on the card's four buttons, the missing digits are filled in and the card's magnetic strip is populated with data. Both the digits and the strip become blank again after a short time. "If this card is lost, it's just dead plastic to anyone who finds it," says Mullen, who thinks it could help banks attract security-conscious consumers.

That may be true, says Avivah Litan, a Gartner analyst who researches security and technology in the financial sector, but "most card data is stolen electronically, in large volumes," she notes. As a result, banks "may prevent a few percentage points [of fraud], but it seems unlikely to be worth the investment for them."

The MultiAccount card may be more attractive to the financial sector than the "Hidden" card. "It could help the very large card issuers, such as Chase, that have a lot of overlap between their credit and debit accounts," says Litan. However, convincing banks to invest in an unproven technology will require the potential for a very strong effect on their bottom lines, she says.

Mullen says Dynamics's cards are significantly more expensive to produce than standard credit cards, but argues that the additional cost is offset by the benefits to a bank. "These cards are significant revenue generators for them, not cost centers," he says.

Banks already target different types of cards to particular demographics, and use reward schemes to attract new business and encourage heavy use of their products. Cards with computational smarts inside could enable more of that, Mullen argues. For example, a credit card that can suddenly act as a loyalty card might encourage customers to use a scheme that they otherwise wouldn't.

"Cards with this technology have been used in large numbers in stealth trials in the U.S. since earlier this year," says Mullen, who adds that banking partners will begin talking about their plans for the technology in coming months. A particular attraction for banks, he says, is that the cards are compatible with existing infrastructure, unlike contactless payments based on RFID chips.

"There are 16 million magnetic stripe readers in the world," he says. "It's hard to change that, but easy to upgrade your own cards without building new infrastructure."

Dynamics is also working on cards that include E Ink-style displays that remain switched on for longer periods, and the company is also investigating a card that can transfer more data. Typically only a third of the magnetic strip on a card carries the card's details, says Mullen. "You can send messages between card and reader using the rest of that area."

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Surprisingly Regular Patterns in Hurricane Energy Discovered

Surprisingly Regular Patterns in Hurricane Energy Discovered

  11:37:00 PM    Science Lover

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Researchers at the Mathematics Research Centre and Universitat Autònoma de Barcelona have discovered the mathematical relation between the number of hurricanes produced in certain parts of Earth and the energy they release. The distribution is valid for all series of hurricanes under study, independent of when and where they occurred.

Meteorologist puts his finger on the eye of a 
hurricane. Earth image: visibleearth.nasa.gov. 
(Credit: iStockphoto/Eric Hood)

The research, published in Nature Physics, suggests that the evolution of hurricane intensity will be very difficult to predict.

It is well known that there are fewer probabilities of a devastating hurricane developing than of a modest one. However, the exact relation between the number of hurricanes and energy released was not known until now. Researchers from the Mathematics Research Centre (CRM) and the Department of Physics of Universitat Autònoma de Barcelona have analysed data corresponding to tropical cyclones (generic name used for hurricanes) which have appeared in different parts of the planet between 1945 and 2007. Scientists have discovered that this relation corresponds to a power-law, a precise mathematical formula cyclones obey in a surprising manner, regardless of where on the planet and when they appear.

This fundamental discovery has led researchers to more general conclusions on the behaviour of hurricanes. The first conclusion states that a hurricane's dynamics can be the result of a critical process, therefore making it impossible to predict its intensity. One of the aspects traditionally studied by organisations monitoring the danger of hurricanes is the prediction of their intensity, since this determines which alert and prevention systems are to be used in populated areas. Despite the efforts of scientists and resources invested, until now results have been very poor, although predictions on hurricane trajectory have improved considerably. The fact that hurricanes follow this power-law, as do other natural phenomena where large amounts of energy are released, e.g. earthquakes, questions the ability to predict the evolution of their intensity. In these types of processes, the dynamics behind large hurricanes are the same as those producing tropical storms of less importance and range. The way in which a small storm evolves and transforms into a catastrophic hurricane depends on whether the fluctuations amplifying the storm are stronger than those which tend to dissipate it. However, there is no specific aspect pointing to which will be the dominant fluctuations, since the system at that moment is in a critical situation, i.e. on the verge of either dissipating or growing.

The second conclusion of the study is related to the effects of global warming on the behaviour of tropical cyclones: a recent increase in activities in the North Atlantic has shown to follow the same pattern as other high-activity periods in the past. Although there has been a dramatic increase in the number of hurricanes occurring in the North Atlantic since mid-1990s when compared to the period starting in the 1970s, the distribution of hurricanes in the 1950s was similar to today's activity level. Therefore, this increase cannot be explained solely on the basis of climate change. Even so, the research points to the existence of a relation between global warming and the distribution of tropical cyclones. The number of hurricanes is inversely proportional to the energy released, except for the highest values of energy, where the relation is suddenly interrupted. Researchers have observed that the cut-off point where the power-law does not represent the behaviour of hurricanes is influenced by factors such as average sea surface temperature and the El Niño phenomenon. Thus at a higher temperature, for example, the cut-off point rises to higher energy values.

The research was carried out by Álvaro Corral, researcher at Mathematics Research Centre (consortium formed by the Institute of Catalan Studies and the Catalan Government, located at the UAB Research Park; CRM is also a CERCA center); Albert Ossó, UAB student in Physics; and Dr Josep Enric Llebot, professor at the UAB Department of Physics.

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Brain's Energy Restored During Sleep

Brain's Energy Restored During Sleep

  2:29:00 AM    Science Lover

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In the initial stages of sleep, energy levels increase dramatically in brain regions found to be active during waking hours, according to new research in the June 30 issue of the Journal of Neuroscience. These results suggest that a surge of cellular energy may replenish brain processes needed to function normally while awake.

currency of cells, in rats increased in four key brain regions normally active during wakefulness. Shown here is the energy surge measured in the frontal cortex, a brain region associated with higher-level thinking. (Credit: Courtesy, with permission: Dworak et al. The Journal of Neuroscience 2010.)

A good night's rest has clear restorative benefits, but evidence of the actual biological processes that occur during sleep has been elusive. Radhika Basheer, PhD, and Robert McCarley, MD, of Boston V.A. Healthcare System and Harvard Medical School, proposed that brain energy levels are key to nightly restoration.

"Our finding bears on one of the perennial conundrums in biology: the function of sleep," Basheer said. "Somewhat surprisingly, there have been no modern-era studies of brain energy using the most sensitive measurements."

The authors measured levels of adenosine triphosphate (ATP), the energy currency of cells, in rats. They found that ATP levels in four key brain regions normally active during wakefulness increased when the rats were in non-REM sleep, but were accompanied by an overall decrease in brain activity. When the animals were awake, ATP levels were steady. When the rats were gently nudged to stay awake three or six hours past their normal sleep times, there was no increase in ATP.

The authors conclude that sleep is necessary for this ATP energy surge, as keeping the rats awake prevented the surge. The energy increase may then power restorative processes absent during wakefulness, because brain cells consume large amounts of energy just performing daily waking functions.

"This research provides intriguing evidence that a sleep-dependent energy surge is needed to facilitate the restorative biosynthetic processes," said Robert Greene, MD, PhD, of the University of Texas Southwestern, a sleep expert who was unaffiliated with the study. He observed that questions arise from the findings, such as the specific cause of the ATP surge. "The authors propose that the surge is related to decreases in brain cell activity during sleep, but it may be due to many other factors as well, including cellular signaling in the brain," he said.

The research was supported by the Department of Veterans Affairs, a Deutsche Forschungsgemeinschaft Fellowship, and the National Institute of Mental Health.

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Inbred Sperm Fertilize Fewer Eggs, Beetle Study Finds

Inbred Sperm Fertilize Fewer Eggs, Beetle Study Finds

  2:41:00 PM    Science Lover

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Inbred male sperm have been found to fertilize fewer eggs when in competition with non-inbred males, according to a new study by the University of East Anglia.

Red flour beetle. (Credit: Image courtesy of 
University of East Anglia)

Research into the breeding habits of the red flour beetle, published in Proceedings of the Royal Society B, shows that the reduced fitness of inbred beetles, known as 'inbreeding depression', reveals itself in competitive scenarios.

Inbreeding is a potentially important problem in declining species across the world, and conserving genetic variation is now recognized as a priority by the International Union for Conservation of Nature. The new research is potentially vital for the successful implementation of recovery programs of inbred species.

When populations deplete or fragment, relatives can be forced into reproduction, often leading to inbreeding depression.

Led by Dr. Matt Gage, the new research into the promiscuous red flour beetle (Tribolium castaneum) measured how male reproduction responded to forced inbreeding.

After mating brothers with sisters for eight generations, the research found no changes in male fertility or mating behavior.

However, inbred male sperm fertilized fewer eggs when in competition with another non-inbred male, and sperm became more variable in size.

Dr. Gage said: "The experiment was designed to make comparisons with non-inbred control lines. Using multiple inbred lines, we measured the effects of inbreeding on pre- and post-mating success, in the absence and presence of male-male competition."

The results showed no differences between inbred and non-inbred males in terms of mating success, latency, duration, the number of mounts or persistency in a non-competitive setting.

However inbred males suffered significantly reduced sperm competitiveness, fathering an average of 15 per cent fewer offspring than non-inbred males across 330 sperm competition comparisons.

Dr. Gage said: "It seems that inbreeding depression in sperm competitiveness was caused by a decrease in either sperm quantity or quality that is critical for relative competitiveness, but still allows full male fertilization success to be achieved under benign, competition-free conditions.

"We have shown that male fertility and mating competence are not affected by inbreeding and that any decline in sperm quality under inbreeding is only detectable when sperm competition is invoked.

"One limitation to this study is that the ancestral laboratory stock we have used is likely to carry relatively reduced genetic diversity. Also insect sperm do not generally manifest cellular abnormalities akin to those commonly found in more complex mammalian sperm," he added.

The next stage of the research will explore ways that female beetles use multiple mating to generate sperm competition and thereby avoid inbreeding depression of their own fertility.

The research is part of a three-year £400,000 project funded by the Natural Environmental Research Council (NERC). The overall results will help managers of conservation and captive breeding projects recognize when inbreeding is a problem, how it progresses and how best to manage or reverse it.

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Secondhand Smoke Associated With Psychiatric Distress, Illness

Secondhand Smoke Associated With Psychiatric Distress, Illness

  1:21:00 AM    Science Lover

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Exposure to secondhand smoke appears to be associated with psychological distress and the risk of future psychiatric hospitalization among healthy adults, according to a report posted online that will appear in the August print issue of Archives of General Psychiatry.

Second hand smoke exposure is associated with psychological distress and risk of future psychiatric illness (Credit: iStockphoto/Michael Bodmann)

"A growing body of literature has demonstrated the harmful physical health effects of secondhand smoke exposure," the authors write as background information in the article. "Given the highly prevalent exposure to secondhand smoke -- in the United States, an estimated 60 percent of American non-smokers had biological evidence of exposure to secondhand smoke -- even a low level of risk may have a major public health impact."

Mark Hamer, Ph.D., of University College London, and colleagues studied 5,560 non-smoking adults (average age 49.8) and 2,595 smokers (average age 44.8) who did not have a history of mental illness and participated in the Scottish Health Survey in 1998 or 2003. Participants were assessed with a questionnaire about psychological distress, and admissions to psychiatric hospitals were tracked over six years of follow-up. Exposure to secondhand smoke among non-smokers was assessed using saliva levels of cotinine -- the main product formed when nicotine is broken down by the body -- "a reliable and valid circulating biochemical marker of nicotine exposure," the authors write.

A total of 14.5 percent of the participants reported psychological distress. Non-smokers with a high exposure to secondhand smoke (cotinine levels between 0.70 and 15 micrograms per liter) had higher odds of psychological distress when compared with those who had no detectable cotinine.

Over the six-year follow-up, 41 individuals were newly admitted to psychiatric hospitals. Smokers and non-smokers with high exposure to secondhand smoke were both more likely than non-smokers with low levels of secondhand smoke exposure to be hospitalized for depression, schizophrenia, delirium or other psychiatric conditions.

Animal data have suggested that tobacco may induce a negative mood, and some human studies have also identified a potential association between smoking and depression. "Taken together, therefore, our data are consistent with other emerging evidence to suggest a causal role of nicotine exposure in mental health," the authors write.

"To our knowledge, this is the first study to demonstrate a prospective association between objectively assessed secondhand smoke exposure and mental health in a representative sample of a general population," they conclude.

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Why Is Breast Milk Best? It's All in the Genes

Why Is Breast Milk Best? It's All in the Genes

  2:05:00 AM    Science Lover

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Is breast milk so different from infant formula? The ability to track which genes are operating in an infant's intestine has allowed University of Illinois scientists to compare the early development of breast-fed and formula-fed babies. They say the difference is very real.

Breast milk induces genetic pathways that are quite 
different from those in formula-fed infants, new research 
has found. (Credit: iStockphoto/Oleg Kozlov)

"For the first time, we can see that breast milk induces genetic pathways that are quite different from those in formula-fed infants. Although formula makers have tried to develop a product that's as much like breast milk as possible, hundreds of genes were expressed differently in the breast-fed and formula-fed groups," said Sharon Donovan, a U of I professor of nutrition.

Although both breast-fed and formula-fed babies gain weight and seem to develop similarly, scientists have known for a long time that breast milk contains immune-protective components that make a breast-fed infant's risk lower for all kinds of illnesses, she said.

"The intestinal tract of the newborn undergoes marked changes in response to feeding. And the response to human milk exceeds that of formula, suggesting that the bioactive components in breast milk are important in this response," she noted.

"What we haven't known is how breast milk protects the infant and particularly how it regulates the development of the intestine," she said.

Understanding those differences should help formula makers develop a product that is more like the real thing, she said. The scientists hope to develop a signature gene or group of genes to use as a biomarker for breast-fed infants.

Many of the differences found by the scientists were in fundamental genes that regulate the development of the intestine and provide immune defense for the infant.

In this small proof-of-concept study, Donovan used a new technique patented by Texas A&M colleague Robert Chapkin to examine intestinal gene expression in 22 healthy infants -- 12 breast-fed, 10 formula-fed.

The technique involved isolating intestinal cells shed in the infants' stools, then comparing the expression of different genes between the two groups. Mothers in the study collected fecal samples from their babies at one, two, and three months of age. Scientists were then able to isolate high-quality genetic material, focusing on the RNA to get a gene expression or signature.

Donovan said that intestinal cells turn over completely every three days as billions of cells are made, perform their function, and are exfoliated. Examining the shed cells is a noninvasive way to examine intestinal health and see how nutrition affects intestinal development in infants.

Understanding early intestinal development is important for many reasons, she said.

"An infant's gut has to adapt very quickly. A new baby is coming out of a sterile environment, having received all its nutrients intravenously through the placenta. At that point, babies obviously must begin eating, either mother's milk or formula.

"They also start to become colonized with bacteria, so it's very important that the gut learns what's good and what's bad. The baby's body needs to be able to recognize a bad bacteria or a bad virus and fight it, but it also needs to recognize that even though a food protein is foreign, that protein is okay and the body doesn't want to develop an immune response to it," she said.

If anything goes wrong at this stage, babies can develop food allergies, inflammatory bowel disease, and even asthma. "We're very interested in frequent sampling at this early period of development," she added.

Donovan also would like to learn how bacteria in the gut differ in formula- and breast-fed babies, and this technique should make that possible. "Now we'll be able to get a complete picture of what's happening in an infant -- from the composition of the diet to the microbes in the gut and the genes that are activated along the way."

Of potential clinical importance: The gene expressed most often in breast-fed infants is involved in the cell's response to oxygen deprivation. Lack of oxygen is a factor in the development of necrotizing enterocolitis (NEC), a kind of gangrene of the intestine that can be fatal in premature babies. NEC is a leading cause of disease and death in neonatal intensive care units, with a reported 2,500 cases occurring annually in the United States and a mortality rate of 26 percent.

The study will appear in the June 2010 issue of the American Journal of Physiology, Gastrointestinal and Liver Physiology. Co-authors are Robert S. Chapkin, Chen Zhao, Ivan Ivanov, Laurie A. Davidson, Jennifer S. Goldsby, Joanne R. Lupton, and Edward R. Dougherty, all of Texas A&M University, Rose Ann Mathai and Marcia H. Monaco of the U of I, and Deshanie Rai and W. Michael Russell of Mead Johnson Nutrition. The study was funded by Mead Johnson Nutrition.

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Nanotubes Weigh A Single Atom

Nanotubes Weigh A Single Atom

  5:49:00 PM    Science Lover

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How can you weigh a single atom? European researchers have built an exquisite new device that can do just that. It may ultimately allow scientists to study the progress of chemical reactions, molecule by molecule.

A diagram (above) and real-life image (inset) of a carbon nanotube.
(Credit: CARDEQ Project (www.cardeq.eu)

Carbon nanotubes are ultra-thin fibres of carbon and a nanotechnologist’s dream.

They are made from thin sheets of carbon only one atom thick – known as graphene – rolled into a tube only a few nanometres across. Even the thickest is more than a thousand times thinner than a human hair.

Interest in carbon nanotubes blossomed in the 1990s when they were found to possess impressive characteristics that make them very attractive raw materials for nanotechnology of all kinds.

“They have unique properties,” explains Professor Pertti Hakonen of Helsinki University of Technology. “They are about 1000 times stronger than steel and very good thermal conductors and good electrical conductors.”

Hakonen is coordinator of the EU-funded CARDEQ project (http://www.cardeq.eu/) which is exploiting these intriguing materials to build a device sensitive enough to measure the masses of atoms and molecules.

Vibrating strings

A carbon nanotube is essentially an extremely thin, but stiff, piece of string and, like other strings, it can vibrate. As all guitar players know, heavy strings vibrate more slowly than lighter strings, so if a suspended carbon nanotube is allowed to vibrate at its natural frequency, that frequency will fall if atoms or molecules become attached to it.

It sounds simple and the idea is not new. What is new is the delicate sensing system needed to detect the vibration and measure its frequency. Some nanotubes turn out to be semiconductors, depending on how the graphene sheet is wound, and it is these that offer the solution that CARDEQ has developed.

Members of the consortium have taken the approach of building a semiconducting nanotube into a transistor so that the vibration modulates the current passing through it. “The suspended nanotube is, at the same time, the vibrating element and the readout element of the transistor,” Hakonen explains.

“The idea was to run three different detector plans in parallel and then select the best one,” he says. “Now we are down to two. So we have the single electron transfer concept, which is more sensitive, and the field effect transistor concept, which is faster.”

Single atoms

Last November, CARDEQ partners in Barcelona reported that they had sensed the mass of single chromium atoms deposited on a nanotube. But Hakonen says that even smaller atoms, of argon, can now be detected, though the device is not yet stable enough for such sensitivity to be routine. “When the device is operating well, we can see a single argon atom on short time scales. But then if you measure too long the noise becomes large.”

CARDEQ is not alone in employing carbon nanotubes as mass sensors. Similar work is going on at two centres in California – Berkeley and Caltech – though each has adopted a different method to measuring the mass.

All three groups have announced they can perform mass detection on the atomic level using nanotubes, but CARDEQ researchers provided the most convincing data with a clear shift in the resonance frequency.

But a single atom is nowhere near the limit of what is possible. Hakonen is confident they can push the technology to detect the mass of a single nucleon – a proton or neutron.

“It’s a big difference,” he admits, “but typically the improvements in these devices are jump-like. It’s not like developing some well-known device where we have only small improvements from time to time. This is really front-line work and breakthroughs do occur occasionally.”

Biological molecules

If the resolution can be pared down to a single nucleon, then researchers can look forward to accurately weighing different types of molecules and atoms in real time.

It may then become possible to observe the radioactive decay of a single nucleus and to study other types of quantum mechanical phenomena.

But the real excitement would be in tracking chemical and biological reactions involving individual atoms and molecules reacting right there on the vibrating nanotube. That could have applications in molecular biology, allowing scientists to study the basic processes of life in unprecedented detail. Such practical applications are probably ten years away, Hakonen estimates.

“It will depend very much on how the technology for processing carbon nanotubes develops. I cannot predict what will happen, but I think chemical reactions in various systems, such as proteins and so on, will be the main applications in the future.”

The CARDEQ project received funding from the FET-Open strand of the EU’s Sixth Framework Programme for ICT research.

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New Nanoparticles Could Lead To End Of Chemotherapy

New Nanoparticles Could Lead To End Of Chemotherapy

  9:56:00 PM    Science Lover

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Nanoparticles specially engineered by University of Central Florida Assistant Professor J. Manuel Perez and his colleagues could someday target and destroy tumors, sparing patients from toxic, whole-body chemotherapies.

Dr. Manuel Perez and his team have been investigating
the use of nanoparticles for medicine for years.
(Credit: Jacque Brund)

Perez and his team used a drug called Taxol for their cell culture studies, recently published in the journal Small, because it is one of the most widely used chemotherapeutic drugs. Taxol normally causes many negative side effects because it travels throughout the body and damages healthy tissue as well as cancer cells.

The Taxol-carrying nanoparticles engineered in Perez's laboratory are modified so they carry the drug only to the cancer cells, allowing targeted cancer treatment without harming healthy cells. This is achieved by attaching a vitamin (folic acid) derivative that cancer cells like to consume in high amounts.

Because the nanoparticles also carry a fluorescent dye and an iron oxide magnetic core, their locations within the cells and the body can be seen by optical imaging and magnetic resonance imaging (MRI). That allows a physician to see how the tumor is responding to the treatment.

The nanoparticles also can be engineered without the drug and used as imaging (contrast) agents for cancer. If there is no cancer, the biodegradable nanoparticles will not bind to the tissue and will be eliminated by the liver. The iron oxide core will be utilized as regular iron in the body.

"What's unique about our work is that the nanoparticle has a dual role, as a diagnostic and therapeutic agent in a biodegradable and biocompatible vehicle," Perez said.

Perez has spent the past five years looking at ways nanotechnology can be used to help diagnose, image and treat cancer and infectious diseases. It's part of the quickly evolving world of nanomedicine.

The process works like this. Cancer cells in the tumor connect with the engineered nanoparticles via cell receptors that can be regarded as "doors" or "docking stations." The nanoparticles enter the cell and release their cargo of iron oxide, fluorescent dye and drugs, allowing dual imaging and treatment.

"Although the results from the cell cultures are preliminary, they are very encouraging," Perez said.

A new chemistry called "click chemistry" was utilized to attach the targeting molecule (folic acid) to the nanoparticles. This chemistry allows for the easy and specific attachment of molecules to nanoparticles without unwanted side products. It also allows for the easy attachment of other molecules to nanoparticles to specifically seek out particular tumors and other malignancies.

Perez's study builds on his prior research published in the prestigious journal Angewandte Chemie Int. Ed. His work has been partially funded by a National Institutes of Health grant and a Nanoscience Technology Center start-up fund.

"Our work is an important beginning, because it demonstrates an avenue for using nanotechnology not only to diagnose but also to treat cancer, potentially at an early stage," Perez said.

Perez, a Puerto Rico native, joined UCF in 2005. He works at UCF's NanoScience Technology Center and Chemistry Department and in the Burnett School of Biomedical Sciences in the College of Medicine. He has a Ph.D. from Boston University in Biochemistry and completed postdoctoral training at Massachusetts General Hospital, Harvard Medical School's teaching and research hospital.

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Hydrogen Cars Closer To Reality With New Storage System

Hydrogen Cars Closer To Reality With New Storage System

  1:11:00 AM    Science Lover

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Issam Mudawar, from left, a Purdue professor of mechanical engineering, discusses a
hydrogen-storage system for cars with graduate student Milan Visaria and Timothée
Pourpoint, an assistant professor of aeronautics and astronautics and manager of the
Hydrogen Systems Laboratory. Researchers have created the system's heat exchanger,
which is critical because it allows the system to be filled quickly. The research is funded
by General Motors Corp. (Credit: Purdue News Service photo/Andrew Hancock)

Researchers have developed a critical part of a hydrogen storage system for cars that makes it possible to fill up a vehicle's fuel tank within five minutes with enough hydrogen to drive 300 miles.

The system uses a fine powder called metal hydride to absorb hydrogen gas. The researchers have created the system's heat exchanger, which circulates coolant through tubes and uses fins to remove heat generated as the hydrogen is absorbed by the powder.

The heat exchanger is critical because the system stops absorbing hydrogen effectively if it overheats, said Issam Mudawar, a professor of mechanical engineering who is leading the research.

"The hydride produces an enormous amount of heat," Mudawar said. "It would take a minimum of 40 minutes to fill the tank without cooling, and that would be entirely impractical."

Researchers envision a system that would enable motorists to fill their car with hydrogen within a few minutes. The hydrogen would then be used to power a fuel cell to generate electricity to drive an electric motor.

The research, funded by General Motors Corp. and directed by GM researchers Darsh Kumar, Michael Herrmann and Abbas Nazri, is based at the Hydrogen Systems Laboratory at Purdue's Maurice J. Zucrow Laboratories. In February, the team applied for three provisional patents related to this technology.

"The idea is to have a system that fills the tank and at the same time uses accessory connectors that supply coolant to extract the heat," said Mudawar, who is working with mechanical engineering graduate student Milan Visaria and Timothée Pourpoint, a research assistant professor of aeronautics and astronautics and manager of the Hydrogen Systems Laboratory. "This presented an engineering challenge because we had to figure out how to fill the fuel vessel with hydrogen quickly while also removing the heat efficiently. The problem is, nobody had ever designed this type of heat exchanger before. It's a whole new animal that we designed from scratch."

The metal hydride is contained in compartments inside the storage "pressure vessel." Hydrogen gas is pumped into the vessel at high pressure and absorbed by the powder.

"This process is reversible, meaning the hydrogen gas may be released from the metal hydride by decreasing the pressure in the storage vessel," Mudawar said. "The heat exchanger is fitted inside the hydrogen storage pressure vessel. Due to space constraints, it is essential that the heat exchanger occupy the least volume to maximize room for hydrogen storage."

Conventional automotive coolant flows through a U-shaped tube traversing the length of the pressure vessel and heat exchanger. The heat exchanger, which is made mostly of aluminum, contains a network of thin fins that provide an efficient cooling path between the metal hydride and the coolant.

"This milestone paves the way for practical on-board hydrogen storage systems that can be charged multiple times in much the same way a gasoline tank is charged today," said Kumar, a researcher at GM's Chemical & Environmental Sciences Laboratory and the GM R&D Center in Warren, Mich. "As newer and better metal hydrides are developed by research teams worldwide, the heat exchanger design will provide a ready solution for the automobile industry."

The researchers have developed the system over the past two years. Because metal hydride reacts readily with both air and moisture, the system must be assembled in an airtight chamber, Pourpoint said.

Research activities at the hydrogen laboratory involve faculty members from the schools of aeronautics and astronautics, mechanical engineering, and electrical and computer engineering.

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Soon, a portable unit of surgical robots to replace army medics on battlefields

Soon, a portable unit of surgical robots to replace army medics on battlefields

  8:20:00 PM    Science Lover

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The Trauma Pod unit in action

Researchers in the US are working on a project that could replace army medics on a battlefield with robotic surgeons and nurses in the next 10 years.

The ‘Trauma Pod’ – being developed by US’ Defence Advanced Research Projects Agency (DARPA) - is currently undergoing trials.

Brendan Visser, a surgeon at Stanford University in California who helped develop the Trauma Pod, described it as: “Three separate robots dance over the top of the patient with their powerful arms moving very quickly, yet they don’t crash and they’re able to deliver very small items from one arm to another.”

The purpose of the Trauma Pod is to provide a quick “temporary fix” to wounded soldiers before being taken to the hospital.

“The system will focus on damage control surgery, which is the minimum necessary to stabilise someone. It could provide airway control, relieve life-threatening injuries such as a collapsed lung, or stop bleeding temporarily,” Pablo Garcia – of non-profit lab SRI International, which leads the project – told New Scientist magazine.

HOW IT WORKS

The Trauma Pod unit comprises one three-armed surgeon robot, assisted by 12 other robotic systems.

Remotely controlled by a human, the surgeon bot communicates with and instructs the other robots. One of its three arms holds an endoscope to allow the human controller to see inside the patient, while the other two grip surgical tools.

Garcia added that the robot could be allowed to carry out some simple tasks without human help, such as placing stitches or tying knots.

The bed itself monitors vital signs, administers fluids and oxygen, and may eventually administer anaesthesia.

A voice-activated robotic arm “Hot Lips” - derived from the nickname of a nurse in the TV series M*A*S*H - passes fresh tools and supplies to the surgeon bot. A third “circulating nurse” robot gives out the right tools.

The Trauma Pod unit recently passed the first phase of a feasibility trial, where robots treated a mannequin with bullet injuries by inserting a plastic tube into a damaged blood vessel and operating to close a perforated bowel.

The team hopes to eventually shrink the Trauma Pod to a collapsible unit encased in a portable shell that can be carried on the back of a vehicle.

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Turning chickens into dinosaurs!

Turning chickens into dinosaurs!

  9:17:00 AM    Science Lover

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Palaeontologist Jack Horner is working on a project to create a ‘chickenosaur’ or a ‘dinochicken’, wherein scientists will reverse engineer certain genes in chickens, which have previously been found reported to be direct descendants of dinos

In an awe-inspiring new experiment, US palaeontologists are attempting “reverse evolution”, in which they would try to recreate a dinosaur by starting with a chicken embryo and then working backward to engineer a new “chickenosaurus” or “dinochicken”.

According to a report in Discovery News, such “reverse evolution” has been successfully performed in mice and flies, but those studies focused on re-introducing just a few bygone traits.

The dinochicken project, instead, aims to bring back multiple dinosaur characteristics – such as a tail, teeth and forearms – by changing the levels of regulatory proteins that have evolved to suppress these characteristics in birds.

“Birds are dinosaurs, so technically we’re making a dinosaur out of a dinosaur,” said palaeontologist and project leader Jack Horner of the Montana State University.

“The only reason we’re using chickens instead of some other bird is that the chicken genome has been mapped, and chickens have already been exhaustively studied,” he added.

Although the plan seems more like out of the movie Jurassic Park, Horner assured it is real and is already underway.

“A number of people in a number of different places are moving forward with the project slowly and carefully,” he said.

One such researcher is Hans Laarson of McGill University in Canada, who is now analysing the genes involved in tail development and researching ways of manipulating chicken embryos in order to “awaken the dinosaur within”.

“There is a lot of information stored in our genes that we don’t use – genes that determine features that evolution has suppressed, for various reasons,” said Kevin Padian, a professor of integrative biology at the University of California, Berkeley and a curator at the UC Museum of Paleontology.

“We now have the tools to ‘reverse-engineer’ some of those constraints and produce traits that look a bit more like those ancient features,” he added. “This tells us how genetics, development and evolution are related, so it’s tremendously important.”

NOTHING TO WORRY ABOUT

According to Horner, there is no danger of the proposed dinochicken escaping and populating the world with dinosaurs, since only the chicken’s development - and not its genome - would have been affected.

So even if it did somehow escape and could mate, the result would just be a regular chicken, the palaeontologist said.

In any case, if a chicken embryo does not grow properly in the lab, or if it could not survive comfortably, then “we would never let it hatch”, Horner said.

When and if the chickenosaurus is created, he looks forward to bringing it out on a leash during lectures: “We’re always looking for novel ways to get the general public interested in science, and you have to admit, it would be better than a slide show for demonstrating evolution!”

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