Digital worlds can help autistic children to develop social skills

AppId is over the quota
AppId is over the quota
ScienceDaily (Oct. 21, 2011) — The benefits of virtual worlds can be used to help autistic children develop social skills beyond their anticipated levels, suggest early findings from new research funded by the Economic and Social Research Council (ESRC). Researchers on the Echoes Project have developed an interactive environment which uses multi-touch screen technology where virtual characters on the screen demonstrate gestures and  show children's actions in real time.

During sessions in the virtual environment, primary school children experiment with different social scenarios, allowing the researchers to compare their reactions with those they display in real-world situations.

"Discussions of the data with teachers suggest a fascinating possibility," said project leader Dr Kaska Porayska-Pomsta."Learning environments such as Echoes may allow some children to exceed their potential, behaving and achieving in ways that even teachers who knew them well could not have anticipated."

"A teacher observing a child interacting in such a virtual environment may gain access to a range of behaviours from individual children that would otherwise be difficult or impossible to observe in a classroom," she added.

Early indications of this research are that over a number of sessions some children demonstrate a better quality of interaction within the virtual environment and an increased ability to manage their own behaviour, enabling them to concentrate on following a virtual character's gaze or to focus on a pointing gesture, thus developing the skills vital for good communication and effective learning.

The findings could prove particularly useful in helping children with autism to develop skills they normally find difficult. Dr Porayska-Pomsta said: "Since autistic children have a particular affinity with computers, our research shows it may be possible to use digital technology to help develop their social skills."

"The beauty of it is that there are no real-world consequences, so children can afford to experiment with different social scenarios without real-world risks," she added.

The findings from the Echoes Project will showcase technologies for autism during an event in Birmingham which is part of the ESRC Festival of Social Science in November.

"In the longer term, virtual platforms such as the ones developed in the Echoes project could help young children to realise their potential in new and unexpected ways," concluded Dr Porayska-Pomsta.

Recommend this story on Facebook, Twitter,
and Google +1:

Other bookmarking and sharing tools:

Story Source:

The above story is reprinted from materials provided by Economic and Social Research Council (ESRC).

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

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

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

View the original article here

Homicide, suicide outpace traditional causes of death in pregnant, postpartum women

AppId is over the quota
AppId is over the quota
ScienceDaily (Oct. 20, 2011) — Violent deaths are outpacing traditional causes of maternal mortality, such as hemorrhage and preeclampsia, and conflicts with intimate partner are often a factor, researchers report.

"We found that the mortality rate from homicide and suicide were more common than what we think of as traditional causes of maternal mortality," said Dr. Christie L. Palladino, an obstetrician-gynecologist and educational researcher at Georgia Health Sciences University. "It's not what you want to read, but it's the reality."

The analysis of the Centers for Disease Control and Prevention's National Violent Death Reporting System, a surveillance system from 17 states, found 94 pregnancy-associated suicides and 139 homicides from 2003-07. Overall, 64.4 percent of pregnancy-associated violent deaths -- classified by the CDC as death during pregnancy and the following year -- occurred during pregnancy. The mortality rate was 4.9 per 100,000 live births.

The findings, published in the journal Obstetrics & Gynecology, are a wakeup call for health care providers and families alike about the need for mental health awareness and treatment at a time typically associated with great joy, said Palladino who is working to enhance training of obstetrician-gynecologists in depression diagnosis and treatment.

"We have a lot of studies looking at the effects of pregnancy on the baby but often we don't focus so much on outcomes for moms, and the most disastrous of those for both mom and baby would be suicide," Palladino said. She noted that homicide and suicide are both potentially preventable. "The more we look into ways to prevent suicide, ways to effectively manage women with mental health diagnoses during pregnancy and postpartum, the more we can take steps to prevent these deaths," she said.

Among the suicides, 45.7 percent occurred during pregnancy and problems with current or former partners appeared to contribute to more than half. Older, Caucasian women were at greatest risk. Among homicides, 77.7 percent occurred during pregnancy and more than half the women were age 24 or younger and unmarried. Nearly half were black, even though black women accounted for less than 20 percent of the live births, and 45 percent were associated with violence from a current or former partner.

In follow-up, Palladino is surveying practicing physicians about their practice patterns in treating depression during pregnancy. She and her colleagues also want to learn more about precipitating circumstances such as substance abuse, stress and mental illness and treatment. Studies already indicate that intervention lowers the recurrence risk of intimate partner violence in pregnancy and postpartum.

It was her early experience as an obstetrician-gynecologist who felt ill-prepared to treat depression in pregnant women that got her interested in the topic. A 2003 report in The British Journal of Psychiatry identifying suicide as the leading cause of maternal death in Great Britain sealed the deal. "Unfortunately what we found paralleled the Great Britain findings," Palladino said.

The good news is that evidence-based guidelines for depression treatment during pregnancy or postpartum have been developed by The American College of Obstetricians and Gynecologists and The American Psychiatric Association, she said. The bad news is that women and their providers might be hesitant to seek or provide care because mental illness and pregnancy seem counterintuitive.

Collateral materials such as police, coroner and medical examiner reports also were examined as part of the CDC database to provide greater context for the cause of death. While the overall pregnancy-associated violent death rate was stable over the four-year study period, those numbers could be underreported because the pregnancy or postpartum status was marked "unknown" in the majority of female deaths in the CDC database, the researchers noted. Pregnancy or postpartum status also could be missed because autopsies might not include a pregnancy exam, might miss postpartum signs or might fail to report pregnancy status on death certificates.

States participating in the CDC violent death database include South Carolina, Georgia, North Carolina, Virginia, New Jersey, Maryland, Alaska, Massachusetts, Oregon, Colorado, Oklahoma, Rhode Island, Wisconsin, California, Kentucky, New Mexico and Utah.

Researchers at the University of Michigan and Johns Hopkins University co-authored the study.

Recommend this story on Facebook, Twitter,
and Google +1:

Other bookmarking and sharing tools:

Story Source:

The above story is reprinted from materials provided by Georgia Health Sciences University.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

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

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

View the original article here

Cooling the warming debate: Major new analysis confirms that global warming is real

AppId is over the quota
AppId is over the quota
ScienceDaily (Oct. 21, 2011) — Global warming is real, according to a major study released Oct. 20. Despite issues raised by climate change skeptics, the Berkeley Earth Surface Temperature study finds reliable evidence of a rise in the average world land temperature of approximately 1°C since the mid-1950s.

Analyzing temperature data from 15 sources, in some cases going as far back as 1800, the Berkeley Earth study directly addressed scientific concerns raised by skeptics, including the urban heat island effect, poor station quality, and the risk of data selection bias.

On the basis of its analysis, according to Berkeley Earth's founder and scientific director, Professor Richard A. Muller, the group concluded that earlier studies based on more limited data by teams in the United States and Britain had accurately estimated the extent of land surface warming.

"Our biggest surprise was that the new results agreed so closely with the warming values published previously by other teams in the U.S. and the U.K.," Muller said. "This confirms that these studies were done carefully and that potential biases identified by climate change skeptics did not seriously affect their conclusions."

Previous studies, carried out by NOAA, NASA, and the Hadley Center, also found that land warming was approximately 1°C since the mid-1950s, and that the urban heat island effect and poor station quality did not bias the results. But their findings were criticized by skeptics who worried that they relied on ad-hoc techniques that meant that the findings could not be duplicated. Robert Rohde, lead scientist for Berkeley Earth, noted that "the Berkeley Earth analysis is the first study to address the issue of data selection bias, by using nearly all of the available data, which includes about 5 times as many station locations as were reviewed by prior groups."

Elizabeth Muller, co-founder and Executive Director of Berkeley Earth, said she hopes the Berkeley Earth findings will help "cool the debate over global warming by addressing many of the valid concerns of the skeptics in a clear and rigorous way." This will be especially important in the run-up to the COP 17 meeting in Durban, South Africa, later this year, where participants will discuss targets for reducing Greenhouse Gas (GHG) emissions for the next commitment period as well as issues such as financing, technology transfer and cooperative action.

The Berkeley Earth team includes physicists, climatologists, and statisticians from California, Oregon, and Georgia. Rohde led the development of a new statistical approach and what Richard Muller called "the Herculean labor" of merging the data sets. One member of the group, Saul Perlmutter, was recently announced as a winner of the 2011 Nobel Prize in Physics (for his work in cosmology).

The Berkeley Earth study did not assess temperature changes in the oceans, which according to the Intergovernmental Panel on Climate Change (IPCC) have not warmed as much as land. When averaged in, they reduce the global surface temperature rise over the past 50 years -- the period during which the human effect on temperatures is discernable -- to about two thirds of one degree Centigrade.

Specifically, the Berkeley Earth study concludes that:

The urban heat island effect is locally large and real, but does not contribute significantly to the average land temperature rise. That's because the urban regions of Earth amount to less than 1% of the land area.About 1/3 of temperature sites around the world reported global cooling over the past 70 years (including much of the United States and northern Europe). But 2/3 of the sites show warming. Individual temperature histories reported from a single location are frequently noisy and/or unreliable, and it is always necessary to compare and combine many records to understand the true pattern of global warming.The large number of sites reporting cooling might help explain some of the skepticism of global warming," Rohde commented. "Global warming is too slow for humans to feel directly, and if your local weather man tells you that temperatures are the same or cooler than they were a hundred years ago it is easy to believe him." In fact, it is very hard to measure weather consistently over decades and centuries, and the presence of sites reporting cooling is a symptom of the noise and local variations that can creep in. A good determination of the rise in global land temperatures can't be done with just a few stations: it takes hundreds -- or better, thousands -- of stations to detect and measure the average warming. Only when many nearby thermometers reproduce the same patterns can we know that the measurements were reliably made.Stations ranked as "poor" in a survey by Anthony Watts and his team of the most important temperature recording stations in the U.S., (known as the USHCN -- the US Historical Climatology Network), showed the same pattern of global warming as stations ranked "OK." Absolute temperatures of poor stations may be higher and less accurate, but the overall global warming trend is the same, and the Berkeley Earth analysis concludes that there is not any undue bias from including poor stations in the survey.

Four scientific papers setting out these conclusions have been submitted for peer review and will form part of the literature for the next IPCC report on Climate Change. They can be accessed on: www.BerkeleyEarth.org. A video animation graphically shows global warming around the world since 1800.

Berkeley Earth is making its preliminary results public, together with its programs and dataset, in order to invite additional scrutiny. Elizabeth Muller said that "one of our goals is to make the science behind global warming readily accessible to the public." Most of the data were previously available on public websites, but in so many different locations and different formats that most people could access only a small subset of the data. The merged database, which combines 1.6 billion records, is now accessible from the Berkeley Earth website: www.BerkeleyEarth.org .

What Berkeley Earth has not done is make an independent assessment of how much of the observed warming is due to human actions, Richard Muller acknowledged. As a next step, Berkeley Earth plans to address the total warming of the oceans, with a view to obtaining a more accurate figure for the total amount of global warming observable.

More information about Berkeley Earth is available at www.BerkeleyEarth.org.

Recommend this story on Facebook, Twitter,
and Google +1:

Other bookmarking and sharing tools:

Story Source:

The above story is reprinted from materials provided by Berkeley Earth Surface Temperature.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

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

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

View the original article here

Fluoride shuttle increases storage capacity: Researchers develop new concept for rechargeable batteries

AppId is over the quota
AppId is over the quota
ScienceDaily (Oct. 21, 2011) — Karlsruhe Institute of Technology (KIT) researchers have developed a new concept for rechargeable batteries. Based on a fluoride shuttle -- the transfer of fluoride anions between the electrodes -- it promises to enhance the storage capacity reached by lithium-ion batteries by several factors. Operational safety is also increased, as it can be done without lithium.

The fluoride-ion battery is presented for the first time in the Journal of Materials Chemistry by Dr. Maximilian Fichtner and Dr. Munnangi Anji Reddy.

Lithium-ion batteries are applied widely, but their storage capacity is limited. In the future, battery systems of enhanced energy density will be needed for mobile applications in particular. Such batteries can store more energy at reduced weight. For this reason, KIT researchers are also conducting research into alternative systems. A completely new concept for secondary batteries based on metal fluorides was developed by Dr. Maximilian Fichtner, Head of the Energy Storage Systems Group, and Dr. Munnangi Anji Reddy at the KIT Institute of Nanotechnology (INT).

Metal fluorides may be applied as conversion materials in lithium-ion batteries. They also allow for lithium-free batteries with a fluoride-containing electrolyte, a metal anode, and metal fluoride cathode, which reach a much better storage capacity and possess improved safety properties. Instead of the lithium cation, the fluoride anion takes over charge transfer. At the cathode and anode, a metal fluoride is formed or reduced. "As several electrons per metal atom can be transferred, this concept allows to reach extraordinarily high energy densities -- up to ten times as high as those of conventional lithium-ion batteries," explains Dr. Maximilian Fichtner.

The KIT researchers are now working on the further development of material design and battery architecture in order to improve the initial capacity and cyclic stability of the fluoride-ion battery. Another challenge lies in the further development of the electrolyte: The solid electrolyte applied so far is suited for applications at elevated temperatures only. It is therefore aimed at finding a liquid electrolyte that is suited for use at room temperature.

Recommend this story on Facebook, Twitter,
and Google +1:

Other bookmarking and sharing tools:

Story Source:

The above story is reprinted from materials provided by Karlsruhe Institute of Technology.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

M. Anji Reddy, M. Fichtner. Batteries based on fluoride shuttle. Journal of Materials Chemistry, 2011; DOI: 10.1039/C1JM13535J

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

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

View the original article here

Simple lifestyle changes can add a decade or more healthy years to the average lifespan, Canadian study shows

AppId is over the quota
AppId is over the quota
ScienceDaily (Oct. 21, 2011) — Health prevention strategies to help Canadians achieve their optimal health potential could add a decade or more of healthy years to the average lifespan and save the economy billions of dollars as a result of reduced cardiovascular disease, says noted cardiologist Dr. Clyde Yancy.

Dr. Yancy, who will deliver the Heart and Stroke Foundation of Canada Lecture at the opening ceremonies of the Canadian Cardiovascular Congress in Vancouver on October 23, will tell delegates that people who follow seven simple steps to a healthy life can expect to live an additional 40 to 50 years after the age of 50.

"Achieving these seven simple lifestyle factors gives people a 90 per cent chance of living to the age of 90 or 100, free of not only heart disease and stroke but from a number of other chronic illnesses including cancer," says Dr. Yancy, a professor of medicine and chief of cardiology at the Northwestern University's Feinberg School of Medicine. He is also the past-president of the American Heart Association.

"By following these steps, we can compress life-threatening disease into the final stages of life and maintain quality of life for the longest possible time." He predicts that, if we act now, we can reverse the tide by 2020.

According to the Heart and Stroke Foundation, every year in Canada about 250,000 potential years of life are lost due to heart disease and stroke, which are two of the three leading causes of death in Canada.

Canadians can achieve optimal health, says Dr. Yancy, by following these steps:

1. GET ACTIVE: Inactivity can shave almost four years off a person's expected lifespan. People who are physically inactive are twice as likely to be at risk for heart disease or stroke.

2. KNOW AND CONTROL CHOLESTEROL LEVELS: Almost 40 per cent of Canadian adults have high blood cholesterol, which can lead to the build up of fatty deposits in your arteries - increasing your risk for heart disease and stroke.

3. FOLLOW A HEALTHY DIET: Healthy eating is one of the most important things you can do to improve your health -- yet about half of Canadians don't meet the healthy eating recommendations.

4. KNOW AND CONTROL BLOOD PRESSURE: High blood pressure - often called a 'silent killer' because it has no warning signs or symptoms - affects one in five Canadians. By knowing and controlling your blood pressure, you can cut your risk of stroke by up to 40 per cent and the risk of heart attack by up to 25 per cent.

5. ACHIEVE AND MAINTAIN A HEALTHY WEIGHT: Almost 60 per cent of Canadian adults are either overweight or obese - major risk factors for heart disease and stroke. Being obese can reduce your life span by almost four years.

6. MANAGE DIABETES: By 2016 an estimated 2.4 million Canadians will live with diabetes.Diabetes increases the risk of high blood pressure, atherosclerosis (narrowing of the arteries), coronary artery disease, and stroke, particularly if your blood sugar levels are poorly controlled.

7. BE TOBACCO FREE: More than 37,000 Canadians die prematurely each year due to tobacco use, and thousands of non-smokers die each year from exposure to second-hand smoke. As soon as you become smoke-free, your risk of heart disease and stroke begins to decrease. After 15 years ,your risk will be nearly that of a non-smoker.

A call for focused prevention strategies

While this goal of optimal health has been achieved by fewer than 10 per cent of the population, "it demonstrates the striking potential that prevention has if it is broadly embraced," says Dr. Yancy. "We know how to prevent heart disease and stroke -- we now need to build the tools to empower our citizens to manage their risk and prevent heart disease."

Dr. Yancy calls on governments to invest in steady and focused prevention strategies. He says that necessary initiatives include a change in current sodium policies, continued progress in tobacco control initiatives, increased green space, and health education.

"Healthy living is key to preventing heart disease and stroke," says Bobbe Wood, president of the Heart and Stroke Foundation of Canada. "The Foundation is committed to raising awareness about heart health and to promoting public policies that facilitate healthy lifestyles and communities."

She says that the Foundation will continue to build on partnerships and policies that have led to a significant reduction of trans fats in the Canadian food supply; stronger tobacco control initiatives; healthy community design; and a continued reduction in the amount of salt in our food products, which has been achieved in part through Health Check™, the Foundation's flagship food information program.

Dr. Yancy adds that improved access to health care that focuses on prevention and control of important risk factors including high blood pressure, high cholesterol and diabetes is also key.

Raising the alarm over looming costs of treating heart disease

Dr. Yancy will also raise the alarm over the looming cost of treating heart disease now and in the future.

With predictions that the direct medical cost of treating heart disease in the U.S. alone could climb to $818 billion in 2030, he says there is a health and economic imperative for governments and societies around the world to embrace prevention strategies.

Heart disease and stroke cost the Canadian economy more than $20.9 billion every year in physician services, hospital costs, lost wages and decreased productivity.

"The opportunity for prevention is not an unrealistic expectation," says Dr. Yancy. "Over the past 40 years the rates of heart disease and stroke have steadily declined." The rate has declined in Canada by 70 per cent since the mid-1950s. In the last decade alone, the rate has declined by 25 per cent.

Unfortunately, says Dr. Yancy, these benefits may be short-lived if the burden of risk, specifically obesity and diabetes, continues to grow, especially in children. "We need to act now."

Recommend this story on Facebook, Twitter,
and Google +1:

Other bookmarking and sharing tools:

Story Source:

The above story is reprinted from materials provided by Heart and Stroke Foundation of Canada.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

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

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

View the original article here

Seeking answers to treat the fear of childbirth

AppId is over the quota
AppId is over the quota
ScienceDaily (Oct. 21, 2011) — A few women are so afraid of giving birth that they avoid becoming pregnant or seek an abortion, even though they want to have children. This fear is related to several serious conditions such as prolonged labour, a greater need for pain relief during labour and an increased risk of an emergency C-section. In some cases, the fear of childbirth is so serious that it can be classified as a specific phobia, such as a fear of dentists or a fear of heights, and leads to avoidance behaviour.

In Oslo, 5-10 per cent of all pregnant women are treated for fear of childbirth. It is the reason underlying about 20 per cent of all planned C-sections. This trend is on the rise, which is unfortunate since C-sections pose a greater risk to the mother and child than a vaginal delivery.

World's largest study of the fear of childbirth

There is very little research-based knowledge about the actual causes of the fear of childbirth.

"The studies conducted up until now have been limited and have had a low response rate. They have also lacked good psychometric measuring instruments for gauging the mental health of the participants," says Malin Eberhard-Gran, a senior researcher at the Norwegian Institute for Public Health. She is the project manager of an extensive study investigating the causal relationships between the risk factors for fear of childbirth and how this fear affects delivery and the child. The "Fear of childbirth: causes and consequences" project is funded in part by the Research Council of Norway's funding scheme for independent projects (FRIPRO).

"This group of pregnant women costs society considerable sums, but as of today we do not know whether we are giving them the proper treatment and follow-up. In addition to the societal perspective, there is also the personal suffering of the women themselves, their families and not least the child to take into consideration."

"This study will enable us to gain more insight into what we are treating as well as how we are treating it," says Dr Eberhard-Gran, who emphasises that a large percentage of women with a fear of childbirth are well functioning in terms of mental health.

"Currently many women who suffer from a fear of childbirth are treated as if they have a classic phobia, but this is wrong. It is not an illness to feel fear. It is actually completely normal to be afraid of giving birth," explains Dr Eberhard-Gran, who wrote her doctoral thesis on post-partum depression.

Involved mothers

"We got an extremely high response rate to our study," says the researcher. "More than 80 per cent of all of the women who gave birth at one of the large hospitals in the Oslo area in the period from 2009 to 2011 took part in the study -- that is almost 4,000 women."

"We believe so many women decided to participate because they wanted to help to enhance the quality of pregnancy checkups and post-partum follow-up in general."

International publication

The researchers have collected large amounts of valuable data that shed light on and document numerous problems related to pregnancy and health.

"So far we have authored nine articles that have either been published in, submitted to or are being assessed for publication by international scientific journals. Three have already been published online," says Dr Eberhard-Gran. The project will be followed up by a study of the respondents two years after giving birth.

Recommend this story on Facebook, Twitter,
and Google +1:

Other bookmarking and sharing tools:

Story Source:

The above story is reprinted from materials provided by The Research Council of Norway.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

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

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

View the original article here

Giant flakes make graphene oxide gel: Discovery could boost metamaterials, high-strength fibers

AppId is over the quota
AppId is over the quota
ScienceDaily (Oct. 20, 2011) — Giant flakes of graphene oxide in water aggregate like a stack of pancakes, but infinitely thinner, and in the process gain characteristics that materials scientists may find delicious.

A new paper by scientists at Rice University and the University of Colorado details how slices of graphene, the single-atom form of carbon, in a solution arrange themselves to form a nematic liquid crystal in which particles are free-floating but aligned.

That much was already known. The new twist is that if the flakes -- in this case, graphene oxide -- are big enough and concentrated enough, they retain their alignment as they form a gel. That gel is a handy precursor for manufacturing metamaterials or fibers with unique mechanical and electronic properties.

The team reported its discovery online this week in the Royal Society of Chemistry journal Soft Matter. Rice authors include Matteo Pasquali, a professor of chemical and biomolecular engineering and of chemistry; James Tour, the T.T. and W.F. Chao Chair in Chemistry as well as a professor of mechanical engineering and materials science and of computer science; postdoctoral research associate Dmitry Kosynkin; and graduate students Budhadipta Dan and Natnael Behabtu. Ivan Smalyukh, an assistant professor of physics at the University of Colorado at Boulder, led research for his group, in which Dan served as a visiting scientist.

"Graphene materials and fluid phases are a great research area," Pasquali said. "From the fundamental point of view, fluid phases comprising flakes are relatively unexplored, and certainly so when the flakes have important electronic properties.

"From the application standpoint, graphene and graphene oxide can be important building blocks in such areas as flexible electronics and conductive and high-strength materials, and can serve as templates for ordering plasmonic structures," he said.

By "giant," the researchers referred to irregular flakes of graphene oxide up to 10,000 times as wide as they are high. (That's still impossibly small: on average, roughly 12 microns wide and less than a nanometer high.) Previous studies showed smaller bits of pristine graphene suspended in acid would form a liquid crystal and that graphene oxide would do likewise in other solutions, including water.

This time the team discovered that if the flakes are big enough and concentrated enough, the solution becomes semisolid. When they constrained the gel to a thin pipette and evaporated some of the water, the graphene oxide flakes got closer to each other and stacked up spontaneously, although imperfectly.

"The exciting part for me is the spontaneous ordering of graphene oxide into a liquid crystal, which nobody had observed before," said Behabtu, a member of Pasquali's lab. "It's still a liquid, but it's ordered. That's useful to make fibers, but it could also induce order on other particles like nanorods."

He said it would be a simple matter to heat the concentrated gel and extrude it into something like carbon fiber, with enhanced properties provided by "mix-ins."

Testing the possibilities, the researchers mixed gold microtriangles and glass microrods into the solution, and found both were effectively forced to line up with the pancaking flakes. Their inclusion also helped the team get visual confirmation of the flakes' orientation.

The process offers the possibility of the large-scale ordering and alignment of such plasmonic particles as gold, silver and palladium nanorods, important components in optoelectronic devices and metamaterials, they reported.

Behabtu added that heating the gel "crosslinks the flakes, and that's good for mechanical strength. You can even heat graphene oxide enough to reduce it, stripping out the oxygen and turning it back into graphite."

Co-authors of the paper are Angel Martinez and Julian Evans, graduate students of Smalyukh at the University of Colorado at Boulder.

The Institute for Complex Adaptive Matter, the Colorado Renewable and Sustainable Energy Initiative, the National Science Foundation, the Air Force Research Lab, the Air Force Office of Scientific Research, the Welch Foundation, the U.S. Army Corps of Engineers Environmental Quality and Installation Program and M-I Swaco supported the research.

Recommend this story on Facebook, Twitter,
and Google +1:

Other bookmarking and sharing tools:

Story Source:

The above story is reprinted from materials provided by Rice University.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

Budhadipta Dan, Natnael Behabtu, Angel Martinez, Julian S. Evans, Dmitry V. Kosynkin, James M. Tour, Matteo Pasquali, Ivan I. Smalyukh. Liquid crystals of aqueous, giant graphene oxide flakes. Soft Matter, 2011; DOI: 10.1039/C1SM06418E

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

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

View the original article here