Linking Rapid Climate Change And Human Cultural Evolution

Rapid climate change during the Middle Stone Age, between 80,000 and 40,000 years ago, during the Middle Stone Age, sparked surges in cultural innovation in early modern human populations, according to new research.

The research, published in the journal Nature Communications [21 May], was conducted by a team of scientists from Cardiff University’s School of Earth and Ocean Sciences, the Natural History Museum in London and the University of Barcelona. 

Bifacial points recovered from Blombos Cave, South Africa. The tools were manufactured in the Middle Stone Age and are made of silcrete and finished by pressure flaking.

Credit:  © Christopher Henshilwood, University of the Witwatersrand

The scientists studied a marine sediment core off the coast of South Africa and reconstructed terrestrial climate variability over the last 100,000 years.

Dr Martin Ziegler, Cardiff University School of Earth and Ocean Sciences, said: "We found that South Africa experienced rapid climate transitions toward wetter conditions at times when the Northern Hemisphere experienced extremely cold conditions."

These large Northern Hemisphere cooling events have previously been linked to a change in the Atlantic Ocean circulation that led to a reduced transport of warm water to the high latitudes in the North. In response to this Northern Hemisphere cooling, large parts of the sub-Saharan Africa experienced very dry conditions.

"Our new data however, contrasts with sub-Saharan Africa and demonstrates that the South African climate responded in the opposite direction, with increasing rainfall, that can be associated with a globally occurring southward shift of the tropical monsoon belt."

Marine sediment core recovered from off the coast of South Africa.

Credit: Cardiff University  

Linking climate change with human evolution

Professor Ian Hall, Cardiff University School of Earth and Ocean Sciences, said: "When the timing of these rapidly occurring wet pulses was compared with the archaeological datasets, we found remarkable coincidences.

"The occurrence of several major Middle Stone Age industries fell tightly together with the onset of periods with increased rainfall"

"Similarly, the disappearance of the industries appears to coincide with the transition to drier climatic conditions."

Professor Chris Stringer of London’s Natural History Museum commented "The correspondence between climatic ameliorations and cultural innovations supports the view that population growth fuelled cultural changes, through increased human interactions".

The South African archaeological record is so important because it shows some of the oldest evidence for modern behavior in early humans. This includes the use of symbols, which has been linked to the development of complex language, and personal adornments made of seashells.

"The quality of the southern African data allowed us to make these correlations between climate and behavioural change, but it will require comparable data from other areas before we can say whether this region was uniquely important in the development of modern human culture" added Professor Stringer.

The new study presents the most convincing evidence so far that abrupt climate change was instrumental in this development.

The research was supported by the UK Natural Environment Research Council and is part of the international Gateways training network, funded by the 7th Framework Programme of the European Union.

Contacts and sources:

Cardiff University  

Going Green: Nation Equipped To Grow Serious Amounts Of Pond Scum For Fuel

A new analysis shows that the nation's land and water resources could likely support the growth of enough algae to produce up to 25 billion gallons of algae-based fuel a year in the United States, one-twelfth of the country's yearly needs.

The findings come from an in-depth look at the water resources that would be needed to grow significant amounts of algae in large, specially built shallow ponds. The results were published in the May 7 issue of Environmental Science and Technology, published by the American Chemical Society.

An algae bloom in North Carolina, a region of the country equipped for broad-scale algae growth.

Photo courtesy of Ildar Sagdejev.

"While there are many details still to be worked out, we don't see water issues as a deal breaker for the development of an algae biofuels industry in many areas of the country," said first author Erik Venteris of the Department of Energy's Pacific Northwest National Laboratory.

For the best places to produce algae for fuel, think hot, humid and wet. Especially promising are the Gulf Coast and the Southeastern seaboard.

"The Gulf Coast offers a good combination of warm temperatures, low evaporation, access to an abundance of water, and plenty of fuel-processing facilities," said hydrologist Mark Wigmosta, the leader of the team that did the analysis.

Wooing algae as fuel

Algae, it turns out, are plump with oil, and several research teams and companies are pursuing ways to improve the creation of biofuels based on algae — growing algae composed of more oil, creating algae that live longer and thrive in cooler temperatures, or devising new ways to separate out the useful oil from the rest of the algae.

But first, simply, the algae must grow. The chief requirements are sunlight and water. Antagonists include clouds, a shortage of water, and evaporation.

A previous report by the same team looked mainly at how much demand algae farms would create for freshwater. That report demonstrated that oil based on algae have the potential to replace a significant portion of the nation's oil imports and drew theattention of President Obama.

The new report focuses on actual water supplies and looks at a range of possible sources of water, including fresh groundwater, salty or saline groundwater, and seawater. The team estimates that up to 25 billion gallons of algal oil could be produced annually, an increase of 4 billion gallons over the previous study's estimate. The new amount is enough to fill the nation's current oil needs for one month — about 600 million barrels — each year. The study's authors note that the new estimate is exactly that — an estimate — based to some degree on assumptions about land and water availability and use.

"I'm confident that algal biofuels can be part of the solution to our energy needs, but algal biofuels certainly aren't the whole solution," said Wigmosta. Most important, he notes that the cost of making the fuel far exceeds the cost of traditional gasoline-based products right now.

Big ponds, big potential

An algae farm would likely consist of many ponds, with water maybe six to 15 inches deep. A few companies have built smaller algae farms and are just beginning to churn out huge amounts of algae to convert to fuel; earlier this year, one company sold algae-based oil to customers in California. Players in the algae biofuels arena range from Exxon-Mobil, which launched a $600 million research effort four years ago, to this year's teenage winner of the Intel Science Talent Search, who was recognized for her work developing algae that produce more oil than they normally do.

The availability of water has been one of the biggest concerns regarding the adoption of broad-scale production of algal biofuel. Scientists estimate that fuel created with algae would use much more water than industrial processes used to harness energy from oil, wind, sunlight, or most other forms of raw energy. To produce 25 billion gallons of algae oil, the team estimates that the process annually would require the equivalent of about one-quarter of the amount of water that is now used each year in the entire United States for agriculture. While that is a huge amount, the team notes that the water would come from a multitude of sources: fresh groundwater, salty groundwater, and seawater.

For its analysis, the team limited the amount of freshwater that could be drawn in any one area, assuming that no more than 5 percent of a given watershed's mean annual water flow could be used in algae production. That number is a starting point, says Venteris, who notes that it's the same percentage that the U.S. Environmental Protection Agency allows power plants to use for cooling.

"In arid areas such as the Desert Southwest, 5 percent is probably an overstatement of the amount of water available, but in many other areas that are a lot wetter, such as much of the East, it's likely that much more water would be available," says Venteris.

"While the nation's Desert Southwest has been considered a possible site for vast algae growth using saline water, rapid evaporation in this region make success there more challenging for low- cost production," Venteris added.

Venteris and colleagues weighed the pluses and minuses of the various water sources. They note that freshwater is cheap but in very limited supply in many areas. Saline groundwater is attractive because it's widely available but usually at a much deeper depth, requiring more equipment and technology to pump it to the surface and make it suitable for algae production. Seawater is plentiful, but would require much more infrastructure, most notably the creation of pipelines to move the water from the coast to processing plants.

The team notes that special circumstances, such as particularly tight water restrictions in some areas or severe drought or above-average rainfall in others, could affect its estimates of water availability.

The work was funded by the DOE's Office of Energy Efficiency and Renewable Energy. In addition to Venteris and Wigmosta, PNNL scientists Richard Skaggs and Andre Coleman contributed to the project and authored the study.

Citation: Erik R. Venteris, Richard L. Skaggs, Andre M. Coleman, and Mark S. Wigmosta, A GIS Cost Model to Assess the Availability of Freshwater, Seawater, and Saline Groundwater for Algal Biofuel Production in the United States, Environmental Science and Technology, http://dx.doi.org/10.1021/es304135b.


Contacts and sources:
Tom Rickey
DOE/Pacific Northwest National Laboratory

Allosaurus Fed More Like A Falcon Than A Crocodile, New Study Finds

The mighty T. rex may have thrashed its massive head from side to side to dismember prey, but a new study shows that its smaller cousin Allosaurus was a more dexterous hunter and tugged at prey more like a modern-day falcon.

This illustration shows skeleton and soft tissues of the head and neck of the late Jurassic predatory dinosaur Allosaurus.

Credit: WitmerLab, Ohio University

"Apparently one size doesn't fit all when it comes to dinosaur feeding styles," said Ohio University paleontologist Eric Snively, lead author of the new study published today in Palaeontologia Electronica. "Many people think of Allosaurus as a smaller and earlier version of T. rex, but our engineering analyses show that they were very different predators."

Snively led a diverse team of Ohio University researchers, including experts in mechanical engineering, computer visualization and dinosaur anatomy. They started with a high-resolution cast of the five-foot-long skull plus neck of the 150-million-year-old predatory theropod dinosaur Allosaurus, one of the best known dinosaurs. They CT-scanned the bones at O'Bleness Memorial Hospital in Athens, which produced digital data that the authors could manipulate in a computer.

Snively and mechanical engineer John Cotton applied a specialized engineering analysis borrowed from robotics called multibody dynamics. This allowed the scientists to run sophisticated simulations of the head and neck movements Allosaurus made when attacking prey, stripping flesh from a carcass or even just looking around.

"The engineering approach combines all the biological data—things like where the muscle forces attach and where the joints stop motion—into a single model. We can then simulate the physics and predict what Allosaurus was actually capable of doing," said Cotton, an assistant professor in the Russ College of Engineering and Technology.

A modern-day kestrel (a small falcon) is perched atop the skull of the Jurassic predatory dinosaur Allosaurus. A key finding of the new study is that Allosaurus had a feeding style similar to falcons. In both cases, tearing flesh from carcasses involved grasping meat with the jaws and tugging back and up with the neck and body.

Credit: WitmerLab, Ohio University

To figure out how Allosaurus de-fleshed a Stegosaurus, the team had to "re-flesh" Allosaurus. The anatomical structure of modern-day dinosaur relatives, such as birds and crocodilians, combined with tell-tale clues on the dinosaur bones, allowed Snively and anatomists Lawrence Witmer and Ryan Ridgely to build in neck and jaw muscles, air sinuses, the windpipe and other soft tissues into their Allosaurus 3D computer model.

"Dinosaur bones simply aren't enough," said Witmer, Chang Professor of Paleontology in the Heritage College of Osteopathic Medicine and principal investigator on the National Science Foundation's Visible Interactive Dinosaur Project that provided funding for this research. "We need to know about the other tissues that bring the skeleton to life."

A key finding was an unusually placed neck muscle called longissimus capitis superficialis. In most predatory dinosaurs, such as T. rex, which Snively studied previously, this muscle passed from the side of the neck to a bony wing on the outer back corners of the skull.

"This neck muscle acts like a rider pulling on the reins of a horse's bridle," explained Snively. "If the muscle on one side contracts, it would turn the head in that direction, but if the muscles on both sides pull, it pulls the head straight back."

But the analysis of Allosaurus revealed that the longissimus muscle attached much lower on the skull, which, according to the engineering analyses, would have caused "head ventroflexion followed by retraction."

"Allosaurus was uniquely equipped to drive its head down into prey, hold it there, and then pull the head straight up and back with the neck and body, tearing flesh from the carcass … kind of like how a power shovel or backhoe rips into the ground," Snively said.

In the animal world, this same de-fleshing technique is used by small falcons, such as kestrels. Tyrannosaurs like T. rex, on the other hand, were engineered to use a grab-and-shake technique to tear off hunks of flesh, more like a crocodile.

But the team's engineering analyses revealed a cost to T. rex's feeding style: high rotational inertia. That large bony and toothy skull perched at the end of the neck made it hard for T. rex to speed up or slow down its head or to change its course as it swung its head around.

Allosaurus, however, had a relatively very light head, which the team discovered as they restored the soft tissues and air sinuses. 

Having a lot of mass sitting far away from the axis of head turning, as in T. rex, increases rotational inertia, whereas having a lighter head, as in Allosaurus, decreases rotational inertia, the researchers explained. An ice skater spins faster and faster as she tucks her arms and legs into her body, decreasing her rotational inertia as the mass of her limbs moves closer to the axis of spinning.

"Allosaurus, with its lighter head and neck, was like a skater who starts spinning with her arms tucked in," said Snively, "whereas T. rex, with its massive head and neck and heavy teeth out front, was more like the skater with her arms fully extended … and holding bowling balls in her hands. She and the T. rex need a lot more muscle force to get going."

The end result is that Allosaurus was a much more flexible hunter that could move its head and neck around relatively rapidly and with considerable control. That control, however, came at the cost of brute-force power, requiring a de-fleshing style that, like a falcon, recruited the whole neck and body to strip flesh from the bones.

The Ohio University team will continue to use their engineering approach to explore additional differences in dinosaur feeding styles.

The scientific article is freely available (open-access) on the Palaeontologia Electronica site. The research was funded by National Science Foundation grants to Lawrence Witmer and Ryan Ridgely, as well as by the Department of Mechanical Engineering in the Russ College of Engineering and Technology (John Cotton and Eric Snively) and the Heritage College of Osteopathic Medicine (Witmer, Ridgely and Snively).


Contacts and sources:
Andrea Gibson
Ohio University

Estimates Reveal Low Population Immunity To New Bird Flu Virus H7N9 In Humans

The level of immunity to the recently circulating H7N9 influenza virus in an urban and rural population in Vietnam is very low, according to the first population level study to examine human immunity to the virus, which was previously only found in birds. The findings have implications for planning the public health response to this pandemic threat.

The study used a new, high throughput method that allows blood samples to be analysed for antibodies to multiple human and animal influenza viruses at the same time and is easier to standardise than previous techniques. However, the assay is yet to be validated clinically for the H7N9 virus, and the researchers caution that the results must be interpreted with care.

 H7N9

Credit:  Wikipedia

Since the first case of H7N9 infection in humans was reported in February 2013, there have been 131 confirmed cases and 36 deaths, all in China apart from one case in Taiwan. All of the infections seem to have come from infected poultry and there is no evidence of sustained transmission between people. One of the first key pieces of information that officials need when considering how best to respond to the threat of a pandemic is how much, if any, immunity the human population has to this virus. This helps to predict where the virus is likely to affect first and how likely it is that the virus will spread further. Having this knowledge also helps to understand the risks of severe infection, as well as helping to target protective measures such as where to direct antiviral medication.

Researchers at the Wellcome Trust Oxford University Clinical Research Unit (OUCRU) in Vietnam tested 1723 blood samples collected in southern Vietnam for the presence of antibodies to five different bird flu viruses, including one from the H7 sub type. The presence of antibodies would be an indication of past exposure to these particular strains of flu. They used a new technique that was developed by their research collaborators at the National Institute of Public Health of The Netherlands that is faster and easier to use than previous methods.

The results reveal that although the level of antibodies to the H7 sub-type of flu virus are higher than any of the H5 sub-types tested, levels of antibodies to all five bird flu viruses are much lower than to human flu viruses. This suggests that people living in this particular area of Vietnam have had very little or no exposure to the H7 sub-type of virus, similar to other bird flu viruses. As this population of people would be expected to be among the first to be affected in the event of a pandemic, these findings have important implications for pandemic preparedness plans in this area.

Dr Maciej Boni, a Sir Henry Dale Fellow at the OUCRU and first author of the study, explains: "H7N9 is a virus that until now has only infected birds so it's not surprising that we don't find much evidence of humans having been exposed to it. It is reassuring that in Vietnam we don't see any evidence that the current outbreaks represent a tip-of-the iceberg observation of widespread H7N9 infection in people. On the other hand, the low antibody levels indicate that there is likely to be very little immunity to this virus."

Around half of the samples were taken from an urban environment, Ho Chi Minh City, and half from a rural area, the nearby Khanh Hoa province. The team found no difference in the level of immunity to bird flu viruses between these two populations, even though people living in rural areas are more likely to live in close proximity to poultry.

"It has been suggested that people who live in closer proximity to chickens and other birds will have higher levels of immunity to bird flu viruses simply because their exposure is likely to be greater. However we find no evidence for this. Our findings would suggest that both rural and urban populations should be treated the same when considering how best to respond to the threat of an outbreak," added Dr Boni.

Professor Jeremy Farrar, Director of the Wellcome Trust Major Overseas Programme in Vietnam and the Oxford University Clinical Research Unit Hospital for Tropical Diseases, explains: "This is the first study to give us information about the level of antibodies and potentially human immunity to this new bird flu virus, H7N9 in the region. But we need to interpret the findings cautiously, these assays are relatively new and we need to understand how they correspond to existing assays and how they reflect past infection and true human immunity.

"We know that antibodies are very important for immunity to other flu viruses but at this stage, we still don't know what level of antibody measured using this assay would provide protection against this novel strain. Further studies will be needed to understand the clinical relevance of these new assays, how they compare with classic techniques and what the apparent absence of antibodies to these viruses in the human population means. However these new techniques do allow for much higher throughput of samples, ease of use and once validated may allow much more rapid assessment of the spread of infection and levels of population immunity than do traditional assays."

The study, which was carried out in collaboration with scientists at the National Institute for Public Health and the Environment (RIVM) in the Netherlands, is published online this week in the Journal of Infectious Diseases.

Professor Marion Koopmans, who is Head of Virology at the RIVM and senior author of the study, said: "We developed this technique exactly to be used in the current situation: we wanted a standardised test that allowed us to rapidly compare antibodies to the new virus with those to influenza viruses that we already know are common in people. The level of immunity to a new virus is one of the important questions during any emerging disease outbreak. We need only one drop of blood, so that tests can also be run when only small sample volumes are available, for instance when testing children. For outbreak investigations, testing of animals may be needed, and we are currently working on that. To do the clinical validation studies, we need blood samples from patients (and animals) with confirmed H7N9, and we hope to be able to do that soon through collaborations with other groups working on H7N9."

Contacts and sources:
Jen Middleton
Wellcome Trust

Most Elite Athletes Believe Doping Substances Are Effective In Improving Performance

Most elite athletes consider doping substances "are effective" in improving performance, while recognizing that they constitute cheating, can endanger health and entail the obvious risk of sanction. At the same time, the reasons why athletes start to take doping substances are to achieve athletic success, improve performance, for financial gain, to improve recovery and to prevent nutritional deficiencies, as well as “because other athletes also use them”.

These are some of the conclusions of a study conducted by researchers from the Department of Physical and Sports Education at the University of Granada. Their research has also shown a widespread belief among elite athletes that the fight against doping is inefficient and biased, and that the sanctions imposed "are not severe enough".

University of Granada researchers Mikel Zabala-Díaz and Jaime Morente-Sánchez, authors of the study.

Credit:  University of Granada

In an article in the journal "Sports Medicine", the most important publication in the field of Sport Sciences, researchers Mikel Zabala and Jaime Morente-Sánchez have analysed the attitudes, beliefs and knowledge about doping of elite athletes from all over the world. To this end, they conducted a literature review of 33 studies on the subject published between 2000 and 2011, in order to analyse the current situation and, as a result of this, to act by developing specific, efficient anti-doping strategies.

Fewer controls in team-based sports

The results of the University of Granada study reveal that athletes participating in team-based sports appear to be less susceptible to using doping substances. However, the authors stress that in team sports anti-doping controls are clearly both quantitatively and qualitatively less exhaustive.

The study indicates that coaches seem to be the principle influence and source of information for athletes when it comes to starting or not starting to take banned substances, while doctors and other specialists are less involved. Athletes are becoming increasingly familiar with anti-doping rules, but there is still a lack of knowledge about the problems entailed in using banned substances and methods, which the researchers believe should be remedied through appropriate educational programmes.

Moreover, they also conclude that a substantial lack of information exists among elite athletes about dietary supplements and the secondary effects of performance-enhancing substances.

In the light of their results, the University of Granada researchers consider it necessary to plan and conduct information and prevention campaigns to influence athletes' attitudes towards doping and the culture surrounding this banned practice. “We should not just dedicate money almost exclusively to performing anti-doping tests, as we currently do. To improve the situation, it would be enough to designate at least a small part of this budget to educational and prevention programmes that encourage athletes to reject the use of banned substances and methods”, Mikel Zabala and Jaime Morente-Sánchez conclude. In this context, one pioneering example in their opinion is the Spanish Cycling Federation's “Preventing to win” project.

Citation: Doping in Sport: A Review of Elite Athletes' Attitudes, Beliefs, and Knowledge.
Morente-Sánchez J, Zabala M. Sports Medicine. 2013 Mar 27.


Contacts and sources:
Jaime Morente-Sánchez
University of Granada

Common Food Supplement Fights Degenerative Brain Disorders

Nutritional supplement delays advancement of Parkinson's and Familial Dysautonomia, Tel Aviv University (TAU) researchers discover

Widely available in pharmacies and health stores, phosphatidylserine is a natural food supplement produced from beef, oysters, and soy. Proven to improve cognition and slow memory loss, it's a popular treatment for older people experiencing memory impairment. Now a team headed by Prof. Gil Ast and Dr. Ron Bochner of Tel Aviv University's Department of Human Molecular Genetics has discovered that the same supplement improves the functioning of genes involved in degenerative brain disorders, including Parkinson's disease and Familial Dysautonomia (FD).

Credit: TAU

In FD, a rare genetic disorder that impacts the nervous system and appears almost exclusively in the Ashkenazi Jewish population, a genetic mutation prevents the brain from manufacturing healthy IKAP proteins — which likely have a hand in cell migration and aiding connections between nerves — leading to the early degeneration of neurons. When the supplement was applied to cells taken from FD patients, the gene function improved and an elevation in the level of IKAP protein was observed, reports Prof. Ast. These results were replicated in a second experiment which involved administering the supplement orally to mouse populations with FD.

The findings, which have been published in the journal Human Molecular Genetics, are very encouraging, says Prof. Ast. "That we see such an effect on the brain — the most important organ in relation to this disease — shows that the supplement can pass through the blood-brain barrier even when administered orally, and accumulate in sufficient amounts in the brain."

Slowing the death of nerve cells

Already approved for use as a supplement by the FDA, phosphatidylserine contains a molecule essential for transmitting signals between nerve cells in the brain. Prof. Ast and his fellow researchers decided to test whether the same chemical, which is naturally synthesized in the body and known to boost memory capability, could impact the genetic mutation which leads to FD.

Researchers applied a supplement derived from oysters, provided by the Israeli company Enzymotec, to cells collected from FD patients. Noticing a robust effect on the gene, including a jump in the production of healthy IKAP proteins, they then tested the same supplement on mouse models of FD, engineered with the same genetic mutation that causes the disease in humans.

The mice received the supplement orally, every two days for a period of three months. Researchers then conducted extensive genetic testing to assess the results of the treatment. "We found a significant increase of the protein in all the tissues of the body," reports Prof. Ast, including an eight-fold increase in the liver and 1.5-fold increase in the brain. "While the food supplement does not manufacture new nerve cells, it probably delays the death of existing ones," he adds.

Therapeutic potential for Parkinson's

That the supplement is able to improve conditions in the brain, even when given orally, is a significant finding, notes Prof. Ast. Most medications enter the body through the blood stream, but are incapable of breaking through the barrier between the blood and the brain.

In addition, the researchers say the supplement's positive effects extend beyond the production of IKAP. Not only did phosphatidylserine impact the gene associated with FD, but it also altered the level of a total of 2400 other genes — hundreds of which have been connected to Parkinson's disease in previous studies.

The researchers believe that the supplement may have a beneficial impact on a number of degenerative diseases of the brain, concludes Prof. Ast, including a major potential for the development of new medications which would help tens of millions of people worldwide suffering from these devastating diseases.



Contacts and sources:
George Hunka
American Friends of Tel Aviv University

Understanding Of Water’s Freezing Behavior At Nanoscale

The results of a new study led by George Washington University Professor Tianshu Li provide direct computational evidence that nucleation of ice in small droplets is strongly size-dependent, an important conclusion in understanding water’s behavior at the nanoscale. The formation of ice at the nanoscale is a challenging, basic scientific research question whose answer also has important implications for climate research and other fields.

The crystallization of ice from supercooled water is generally initiated by a process called nucleation. Because of the speed and size of nucleation—it occurs within nanoseconds and nanometers—probing it by experiment or simulation is a major challenge.

By using an advanced simulation method, Dr. Li and his collaborators, Davide Donadio of Germany’s Max Planck Institute for Polymer Research, and Giulia Galli, a professor of chemistry and physics at the University of California, Davis, were able to demonstrate that nucleation of ice is substantially suppressed in nano-sized water droplets. Their paper, “Ice nucleation at the nanoscale probes no man’s land of water,” was published today in the journal Nature Communications. 

Credit: Georgia Tech

“A current challenge for scientists is to unveil water’s behaviors below -35 degrees Celsius and above -123 degrees Celsius, a temperature range that chemists call ‘no man’s land,’ ” said Dr. Li, a professor of civil and environmental engineering at the George Washington University School of Engineering and Applied Science. “Fast ice crystallization can hardly be avoided at such low temperatures, so maintaining water in a liquid state is a major experimental challenge.”

Since the frequency of ice nucleation scales with the volume of water, one of the strategies for overcoming this kinetic barrier is to reduce the volume of water. However, this raises the question of whether water at the nanoscale can still be regarded as equivalent to bulk water, and if not, where that boundary would be.

The team’s results answer this question. By showing that the ice nucleation rate at the nanoscale can be several orders of magnitude smaller than that of bulk water, they demonstrate that water at such a small scale can no longer be considered bulk water.

“We also predict where this boundary would reside at various temperatures,” Dr. Li said. The boundary refers to the size of the droplet where the difference vanishes. The team’s findings will help with the interpretation of molecular beam experiments and set the guidelines for experiments that probe the ‘no man’s land’ of water.

The results are also of importance in atmospheric science, as they may improve the climate model of the formation of ice clouds in upper troposphere, which effectively scatter incoming solar radiation and prevent earth from becoming overheated by the sun. The results have important implications in climate control research, too. One of the current debates is whether the formation of ice occurs near the surface or within the micrometer-sized droplets suspended in clouds. If it is the former, effective engineering approaches may be able to be taken to tune the surface tension of water so that the ice crystallization rate can be controlled.

“Our results, indeed, support the hypothesis of surface crystallization of ice in microscopic water droplets,” Dr. Li said. “Obtaining the direct evidence is our next step.”



Contacts and sources:
Joanne Welsh
George Washington University

Drugs Found To Both Prevent And Treat Alzheimer's Disease In Mice

Scientists hope the pharmaceuticals could lead to the development of a silver bullet for combatting the neurodegenerative disease

Researchers at USC have found that a class of pharmaceuticals can both prevent and treat Alzheimer's Disease in mice.

The drugs, known as "TSPO ligands," are currently used for certain types of neuroimaging.

"We looked at the effects of TSPO ligand in young adult mice when pathology was at an early stage, and in aged mice when pathology was quite severe," said lead researcher Christian Pike of the USC Davis School of Gerontology. "TSPO ligand reduced measures of pathology and improved behavior at both ages."

Christian Pike, lead author of a new study on Alzheimer's disease 

Credit: USC Photo/Dietmar Quistorf

The team's findings were published online by the Journal of Neuroscience on May 15. Pike's coauthors include USC postdoctoral scientists Anna M. Barron, Anusha Jayaraman and Joo-Won Lee; as well as Donatella Caruso and Roberto C. Melcangi of the University of Milan and Luis M. Garcia-Segura of the Instituto Cajal in Spain.

The most surprising finding for Pike and his team was the effect of TSPO ligand in the aged mice. Four treatments—once per week over four weeks—in older mice resulted in a significant decrease of Alzheimer's-related symptoms and improvements in memory – meaning that TSPO ligands may actually reverse some elements of Alzheimer's disease.

"Our data suggests the possibility of drugs that can prevent and treat Alzheimer's," Pike said. "It's just mouse data, but extremely encouraging mouse data. There is a strong possibility that TSPO ligands similar to the ones used in our study could be evaluated for therapeutic efficacy in Alzheimer's patients within the next few years."

Next, the team will next focus on understanding how TSPO ligands reduce Alzheimer's disease pathology. Building on the established knowledge that TSPO ligands can reduce inflammation—shielding nerve cells from injury and increasing the production of neuroactive hormones in the brain—the team will study which of these actions is the most significant in fighting Alzheimer's disease so they can develop newer TSPO ligands accordingly.
 
The research was funded by the National Institutes of Health (grant number AG05142), the American-Australian Association, the Japan Society for the Promotion of Science and the Fondazione San Paolo.


Contacts and sources:
Robert Perkins
University of Southern California

A First: X-47B Unmanned Combat Air System Makes Touch And Go Landing On Aircraft Carrier

An X-47B Unmanned Combat Air System (UCAS) demonstrator conducts a touch and go landing on the flight deck of the aircraft carrier USS George H.W. Bush (CVN 77), marking the first time any unmanned aircraft has completed a touch and go landing at sea. George H.W. Bush is conducting training operations in the Atlantic Ocean.

U.S. Navy video by Mass Communication Specialist 2nd Class Gregory Wilhelmi

The Navy's X-47B Unmanned Combat Air System Demonstrator (UCAS-D) has begun touch and go landing operations aboard the aircraft carrier USS George H.W. Bush (CVN 77) May 17.

For UCAS-D, this represents the most significant technology maturation of the program. Ship relative navigation and precision touchdown of the X-47B are critical technology elements for all future Unmanned Carrier Aviation (UCA) aircraft.

Don Blottenberger, UCAS-D Deputy Program manager, commented, "This landing, rubber hitting deck, is extremely fulfilling for the team and is the culmination of years of relative navigation development. Now, we are set to demonstrate the final pieces of the demonstration."

Earlier in the week, the UCAS-D test team and CVN 77 worked together to successfully complete the first ever launch of an unmanned aircraft from an aircraft carrier proving the importance of introducing unmanned aviation into the already powerful arsenal of aircraft squadrons.

An X-47B unmanned combat air system (UCAS) demonstrator prepares to execute a touch and go landing on the flight deck of the aircraft carrier USS George H.W. Bush (CVN 77). This is the first time any unmanned aircraft has completed a touch and go landing at sea. George H.W. Bush is conducting training operations in the Atlantic Ocean. 

Credit: U.S. Navy photo by Mass Communication Specialist 2nd Class Timothy Walter

"We are proud to be a part of another historic first for Naval Aviation. The landing was spot-on and it's impressive to witness the evolution of the Carrier Air Wing," said Capt. Brian E. Luther, Commanding Officer USS George H.W. Bush (CVN 77)

The various launch and landing operations of the X-47B on the flight deck of George H. W. Bush signify historic events for naval aviation history. These demonstrations display the Navy's readiness to move forward with unmanned carrier aviation operations.

Capt. Jaime Engdahl, program manager for Unmanned Combat Air Systems program office, said, "When we operate in a very dynamic and harsh carrier environment, we need networks and communication links that have high integrity and reliability to ensure mission success and provide precise navigation and placement of an unmanned vehicle."

"Today, we have demonstrated this with the X-47B, and we will continue to demonstrate, consistent, reliable, repeatable touch-down locations on a moving carrier flight deck," he continued. "This precision relative navigation technology is key to ensuring future unmanned systems can operate off our aircraft carriers."

The UCAS-D program plans to conduct shore-based arrested landings of the X-47B at NAS Patuxent River in the coming months before final carrier-based arrestments later in 2013.

George H.W. Bush is currently conducting training operations in the Atlantic Ocean, strengthening the Navy's forward operating and war fighting ability.

Source: U.S. Navy 

3D Printer For Food Being Developed By SMRC For NASA And The World, Will Be Like Replicator From Star Trek

Systems and Materials Research Corporation (SMRC) proposes combining its Manufacturing Technology and Materials Science expertise to address NASA's Advanced Food System Technology needs. Using progressive 3D printing and inkjet technologies, SMRC will design, build, and test a complete nutritional system for long duration missions beyond low earth orbit. The 3D printing component will deliver macronutrients (starch, protein, and fat), structure, and texture while the ink jet will deliver micronutrients, flavor, and smell. 

SMRC will team with the food science program at North Carolina State University and International Flavors and Fragrances to ensure the production of nutritious and flavorful mission supplies. SMRC proposes producing synthetic food which meets the nutritional needs of each and every mission specialist and astronaut.

One of the first foods to be produced is expected to be a pizza

Credit: Wikipedia

 Using unflavored macronutrients, such as protein, starch and fat, the sustenance portion of the diet can be rapidly produced in a variety of shapes and textures directly from the 3D printer (already warm). Since basic sustenance will not ensure the long term physical and mental health of the crew, this is where the microjetting will add value. In addition to adding flavor, low volume micronutrients will be added as the food is processed by the 3D printer. 

The macronutrient feed stocks will be stored in dry sterile containers and fed directly to the printer. At the print head, these stocks will be combined with water or oil per a digital recipe to minimize waste and spoilage. Flavors and texture modifiers can also be added at this stage. This mixture is blended and extruded into the desired shape. The micronutrients and flavors are stored in sterile packs as liquids, aqueous solutions or dispersions. SMRC's approach not only addresses uniform long term storage, sustenance, and micro-nutrition, but also variable and changing dietary needs, variety, and boredom.

POTENTIAL NASA COMMERCIAL APPLICATIONS (Limit 1500 characters, approximately 150 words) 

SMRC will develop a system that is targeted for long duration space missions. This system will include a micro- and macronutrient storage system, mixing system to formulate paste and a 3D dispensing system, where flavored and textured food will be prepared for astronauts. The storage system will provide maximum shelf life for the nutrients for the future space missions. The 3D printing system will provide hot and quick food in addition to personalized nutrition, flavor and taste. Such system can be modified and used during short duration space missions as well, which will eliminate nutrient storage system of the proposed 3D printed food system. The short duration food system will utilize various pastes prepared in advance to print appetizing flavored food. The biggest advantage of 3D printed food technology will be zero waste, which is essential in long-distance space missions.

Potential Non-NASA Applications 

With the anticipated world population of 12 Billion by the end of the century, the current infrastructure of food production and supply will not be able to meet the demand of such a large population. The conventional technologies can only provide marginal efficiency, which is not enough in keeping food prices at affordable level for the population growth. By exploring and implementing technologies such as 3D printing, this may avoid food shortage, inflation, starvation, famine and even food wars. 

In addition, US military can use 3D printed food system during many of their missions. 3D printed food system can reduce military logistics, disposal waste, increase operational efficiency and mission effectiveness especially during wartime. In addition to that, 3D printed food can provide optimal nutrient to the soldiers depending on their personal needs and level of physical activities. Submarines and aircraft carriers can effectively benefit from 3D printed food system, which may reduce their downtime to refill supplies and provide efficiency in executing their missions.

Sources: 

NASA 

Systems and Materials Research Consultancy 

Civilization Ending Cosmic Impact 12,800 Years Ago, Caused Extinction Of Giant Animals

About 12,800 years ago when the Earth was warming and emerging from the last ice age, a dramatic and anomalous event occurred that abruptly reversed climatic conditions back to near-glacial state. According to James Kennett, UC Santa Barbara emeritus professor in earth sciences, this climate switch fundamentally –– and remarkably –– occurred in only one year, heralding the onset of the Younger Dryas cool episode.

This is UCSB Earth Sciences professor emeritus James Kennett.

Credit: Courtesy photo UC Santa Barbara

The cause of this cooling has been much debated, especially because it closely coincided with the abrupt extinction of the majority of the large animals then inhabiting the Americas, as well as the disappearance of the prehistoric Clovis culture, known for its big game hunting.

"What then did cause the extinction of most of these big animals, including mammoths, mastodons, giant ground sloths, American camel and horse, and saber- toothed cats?" asked Kennett, pointing to Charles Darwin's 1845 assessment of the significance of climate change. "Did these extinctions result from human overkill, climatic change or some catastrophic event?" The long debate that has followed, Kennett noted, has recently been stimulated by a growing body of evidence in support of a theory that a major cosmic impact event was involved, a theory proposed by the scientific team that includes Kennett himself.

Now, in one of the most comprehensive related investigations ever, the group has documented a wide distribution of microspherules widely distributed in a layer over 50 million square kilometers on four continents, including North America, including Arlington Canyon on Santa Rosa Island in the Channel Islands. This layer –– the Younger Dryas Boundary (YDB) layer –– also contains peak abundances of other exotic materials, including nanodiamonds and other unusual forms of carbon such as fullerenes, as well as melt-glass and iridium. This new evidence in support of the cosmic impact theory appeared recently in a paper in theProceedings of the National Academy of the Sciences. 

The researchers studied the impact spherules in 18 sites in nine countries on four continents for this study.

Credit: YDB Research Group

This cosmic impact, said Kennett, caused major environmental degradation over wide areas through numerous processes that include continent-wide wildfires and a major increase in atmospheric dust load that blocked the sun long enough to cause starvation of larger animals.

Investigating 18 sites across North America, Europe and the Middle East, Kennett and 28 colleagues from 24 institutions analyzed the spherules, tiny spheres formed by the high temperature melting of rocks and soils that then cooled or quenched rapidly in the atmosphere. The process results from enormous heat and pressures in blasts generated by the cosmic impact, somewhat similar to those produced during atomic explosions, Kennett explained.

But spherules do not form from cosmic collisions alone. Volcanic activity, lightning strikes, and coal seam fires all can create the tiny spheres. So to differentiate between impact spherules and those formed by other processes, the research team utilized scanning electron microscopy and energy dispersive spectrometry on nearly 700 spherule samples collected from the YDB layer. The YDB layer also corresponds with the end of the Clovis age, and is commonly associated with other features such as an overlying "black mat" –– a thin, dark carbon-rich sedimentary layer –– as well as the youngest known Clovis archeological material and megafaunal remains, and abundant charcoal that indicates massive biomass burning resulting from impact.

These are examples of impact spherules collected from different sites.

Credit: YDB Research Group

The results, according to Kennett, are compelling. Examinations of the YDB spherules revealed that while they are consistent with the type of sediment found on the surface of the earth in their areas at the time of impact, they are geochemically dissimilar from volcanic materials. Tests on their remanent magnetism –– the remaining magnetism after the removal of an electric or magnetic influence –– also demonstrated that the spherules could not have formed naturally during lightning strikes.

"Because requisite formation temperatures for the impact spherules are greater than 2,200 degrees Celsius, this finding precludes all but a high temperature cosmic impact event as a natural formation mechanism for melted silica and other minerals," Kennett explained. Experiments by the group have for the first time demonstrated that silica-rich spherules can also form through high temperature incineration of plants, such as oaks, pines, and reeds, because these are known to contain biologically formed silica.

Additionally, according to the study, the surface textures of these spherules are consistent with high temperatures and high-velocity impacts, and they are often fused to other spherules. An estimated 10 million metric tons of impact spherules were deposited across nine countries in the four continents studied. However, the true breadth of the YDB strewnfield is unknown, indicating an impact of major proportions.

"Based on geochemical measurements and morphological observations, this paper offers compelling evidence to reject alternate hypotheses that YDB spherules formed by volcanic or human activity; from the ongoing natural accumulation of space dust; lightning strikes; or by slow geochemical accumulation in sediments," said Kennett.

"This evidence continues to point to a major cosmic impact as the primary cause for the tragic loss of nearly all of the remarkable American large animals that had survived the stresses of many ice age periods only to be knocked out quite recently by this catastrophic event."

Contacts and sources: 

Sonia Fernandez
University of California - Santa Barbara

New Method For Producing Clean Hydrogen

Duke University engineers have developed a novel method for producing clean hydrogen, which could prove essential to weaning society off of fossil fuels and their environmental implications.

While hydrogen is ubiquitous in the environment, producing and collecting molecular hydrogen for transportation and industrial uses is expensive and complicated. Just as importantly, a byproduct of most current methods of producing hydrogen is carbon monoxide, which is toxic to humans and animals.

This is Nico Hotz, left, and Titilayo Shodiya.

Credit: Duke University Photography

The Duke engineers, using a new catalytic approach, have shown in the laboratory that they can reduce carbon monoxide levels to nearly zero in the presence of hydrogen and the harmless byproducts of carbon dioxide and water. They also demonstrated that they could produce hydrogen by reforming fuel at much lower temperatures than conventional methods, which makes it a more practical option.

Catalysts are agents added to promote chemical reactions. In this case, the catalysts were nanoparticle combinations of gold and iron oxide (rust), but not in the traditional sense. Current methods depend on gold nanoparticles' ability to drive the process as the sole catalyst, while the Duke researchers made both the iron oxide and the gold the focus of the catalytic process.

The study appears online in the Journal of Catalysis, viewable at http://www.sciencedirect.com/science/article/pii/S0021951712004204.

"Our ultimate goal is to be able to produce hydrogen for use in fuel cells," said Titilayo "Titi" Shodiya, a graduate student working in the laboratory of senior researcher Nico Hotz, assistant professor of mechanical engineering and materials science at Duke's Pratt School of Engineering. "Everyone is interested in sustainable and non-polluting ways of producing useful energy without fossil fuels," said Shodiya, the paper's first author.

Fuel cells produce electricity through chemical reactions, most commonly involving hydrogen. Also, many industrial processes require hydrogen as a chemical reagent and vehicles are beginning to use hydrogen as a primary fuel source.

"We were able through our system to consistently produce hydrogen with less than 0.002 percent (20 parts per million) of carbon monoxide," Shodiya said.

The Duke researchers achieved these levels by switching the recipe for the nanoparticles used as catalysts for the reactions to oxidize carbon monoxide in hydrogen-rich gases. Traditional methods of cleaning hydrogen, which are not nearly as efficient as this new approach, also involve gold-iron oxide nanoparticles as the catalyst, the researchers said.

"It had been assumed that the iron oxide nanoparticles were only 'scaffolds' holding the gold nanoparticles together, and that the gold was responsible for the chemical reactions," Sodiya said. "However, we found that increasing the surface area of the iron oxide dramatically increased the catalytic activity of the gold."

One of the newest approaches to producing renewable energy is the use of biomass-derived alcohol-based sources, such as methanol. When methanol is treated with steam, or reformed, it creates a hydrogen-rich mixture that can be used in fuel cells.

"The main problem with this approach is that it also produces carbon monoxide, which is not only toxic to life, but also quickly damages the catalyst on fuel cell membranes that are crucial to the functioning of a fuel cell," Hotz said. "It doesn't take much carbon monoxide to ruin these membranes."

The researchers ran the reaction for more than 200 hours and found no reduction in the ability of the catalyst to reduce the amount of carbon monoxide in the hydrogen gas.

"The mechanism for this is not exactly understood yet. However, while current thinking is that the size of the gold particles is key, we believe the emphasis of further research should focus on iron oxide's role in the process," Shodiya said.


###



The Duke team's research was supported by the California Energy Commission and the Oak Ridge Associated Universities. Duke postdoctoral associates Oliver Schmidt and Wen Peng were also part of the research team.

Citation: "Novel nano-scale Au/alpha-Fe2O3 catalyst for the preferential oxidation of CO in biofuel reformate gas," Titilayo Shodiya, et. al, Journal of Catalysis, DOI 10.1016/j.cat.2012.12.027



Contacts and sources:

Tiny Winged Fossil Suggests How Hummingbirds And Swifts Evolved

If all the world's birds, swifts and hummingbirds stand out for their incredible flying abilities. They once had a common ancestor.

Researchers have discovered a 50-million year old fossil in Wyoming that isn't that common ancestor, but a closely related small bird that branched off the same line as the two phenomenal fliers and had characteristics that relate to the remarkable flight abilities of the two birds.

E. rowei was an evolutionary precursor to the group that includes today's swifts and hummingbirds.

Image credit: Lance Grande of the Field Museum of Natural History

Meet Eocypselus rowei, a bird about four-and-a-half-inches long, probably black, and possibly iridescent. It would fit in the palm of your hand and weighed less than an ounce.

The bird was found with most of its feathers preserved, fairly rare in bird fossils.

"This particular lineage went off on its own direction, survived a couple of million years--even made it to Europe--and ultimately died out without leaving any descendants," said Daniel Ksepka of the National Evolutionary Synthesis Center in Durham, North Carolina. "The other side of the fork led to swifts and hummingbirds."

The bird lived in the time after dinosaurs but before humans. The lineage was traced by comparing the fossil to extinct and current birds.

Ksepka and his colleagues from the University of Texas at Austin have a paper in the current issue of theProceedings of the Royal Society B.

The fossil was found under some rocks at the Green River Formation, in a dry lake bed 60 miles across in southwestern Wyoming, where thousands of fossils of all kinds have been found.

"There are tons of fossils," Ksepka said, "insects, vines, palm leaves, crocodiles, turtles, fish, fish eating fish, fish in the process of swallowing other fish." The organisms died, sank to the bottom of the lake and if they were not eaten, became fossils.

The fossil was examined at the Field Museum of Natural History in Chicago and named for John Rowe, chairman of the Field's Board of Trustees.

What makes hummingbirds and swifts unique is what they can do in the air and the remarkable amount of time they spend doing it. They are members of an order called apodiformes, meaning they have very little feet.

"They are the most aerial of all birds," said Kimberly Sue Bostwick, a research associate in ecology and evolutionary biology at Cornell University in Ithaca, N.Y., who was not involved with Ksepka's research. "They are most adept at acrobatics."

Swifts have very tiny feet. For years, most people thought they had none at all, but they have little hooks they can use to grab on to things for sleeping or nesting, the only time those birds are not in the air.

"You never see one on the ground unless it's dead," she said. They can't even take off without the help of wind or gravity.

Swifts zoom around with their mouths open catching insects out of the air, she said. Since there is not much nutrition in insects, they spend all their time catching them.

Hummingbirds can hover unassisted by wind currents, drinking nectar from flowers, the hardest thing a bird can do. They also are never seen alive on the ground, Bostwick said.

Both birds use up huge amounts of energy; burning through calories as they fly and eat.

Ksepka said the feathers on the fossil allowed the researchers to see the shape of the ancient bird's wings.

Hummingbirds have short wings relative to their bodies while swifts have very long, narrow, pointy wings. E. rowei has wings halfway between the two, which meant E. rowei probably didn't hover and would not have been as swift as, well, a swift.

Judging by the shape of its beak, it also ate insects.

The size of the fossil would indicate that the ancestors of swifts and hummingbirds evolved to be small before they gained
their unique flying characteristics, Ksepka said.

Usually, fossils of birds consist of skeletons or just bones, but this one had most of its feathers intact.

The researchers at the Field Museum used a scanning electron microscope to look at the fathers and found carbon residues of tiny cellular organisms called melanosomes, which were once thought to be the remains of bacteria that fed on the feathers. It is now known they contain melanin, pigments that give the feathers color.

"It is reasonably likely these birds were black," Ksepka said, "and possibly shiny."



Contacts and sources:
Joel N. Shurkin, ISNS Contributor

Inside Science News Service

Copper Cookware Could Reduce Food Poisoning

Copper alloys may make more hygienic cooking surfaces than stainless steel, according to a recent study by Sadhana Ravishankar of the UA department of veterinary science and microbiology. Her lab group discovered that copper alloys have antimicrobial effects against the foodborne pathogen Salmonella enterica.

Libin Zhu, Sadhana Ravishankar's lab manager, tested the survivability of Salmonella on copper alloys with varying copper concentrations. The bacteria cells sometimes died out on copper surfaces within hours, while they survived for up to two weeks on stainless steel.

Photo by Beatriz Verdugo/UANews

Each year a tiny, rod-shaped species of bacteria with a fondness for proliferating on human food causes numerous cases of food poisoning around the world, sometimes leading to severe illness and even death.

The culprit, Salmonella enterica, is a leading cause of diarrheal illness worldwide, said Sadhana Ravishankar, an assistant professor in the University of Arizona department of veterinary science and microbiology.
The researchers tested the survivability of Salmonella on six different copper alloys. Bacteria die out on surfaces containing copper much more quickly than on stainless steel surfaces, owing to the antibacterial properties of copper.

Photo by Beatriz Verdugo/UANews

But Ravishankar’s lab may have discovered a way to reduce the number of food poisoning cases due toSalmonella and possibly other bacteria: prepare food on surfaces made with materials that contain some amount of the element copper, known as copper alloys.

Ravishankar’s lab collaborated with Chris Rensing, formerly an associate professor in the UAdepartment of soil, water and environmental sciences and now at Research Triangle Institute International, for the study, which was published recently in the journal Food Microbiology.

“Chris Rensing had already done some research with copper, and he knew that copper surfaces have antimicrobial activity,” said Ravishankar.

The International Copper Association donated six samples of copper alloys for the study, including samples of copper mixed with metals such as nickel, iron, chromium, phosphorous and tin that varied in their copper concentration from 60 to 99.9 percent.

Copper is harmful to bacteria because it reacts with oxygen in the atmosphere over time in a process called oxidation, which produces a residue that is toxic to some bacteria. Oxidation is what makes pure copper change in color over time from a rusty gold to a watery green.

“We decided to see the antimicrobial effect of all these copper alloy surfaces on Salmonella,” said Ravishankar. Salmonella was selected as the microbial guinea pig for the study because of its prevalence and the significant harm it causes worldwide because of diarrheal disease.

The researchers replicated the environments in which bacteria might grow on food contact surfaces. Closed plates reproduced the effects of a wet surface by not allowing humidity to escape, while open plates such as these reproduced a dry surface.

Photo by Beatriz Verdugo/UANews

“Salmonella has caused outbreaks from eating a broad range of different types of foods, including meats and poultry, dairy products, peanut products, ice creams and even chocolate,” said Ravishankar.

Ravishankar found that because of oxidation, food contact surfaces made of materials containing copper are far less habitable for bacteria than stainless steel, which showed no antimicrobial properties at all.

“Right now, food industries use stainless steel,” said Ravishankar, “and stainless steel does not seem to have any antimicrobial activity.” If there are bacteria on a stainless steel surface, she said: “They will survive for a long time.”

One test by Ravishankar’s lab manager, Libin Zhu, showed thatSalmonella can survive for longer than two weeks on stainless steel surfaces. By contrast, the bacteria showed significant reductions on copper alloys.

In most cases, Salmonella on steel surfaces dropped in concentration from 10 million cells to 1 million cells, said Zhu. However, on copper alloys, the concentrations of bacteria dropped by a far greater number, to 100 cells or less.

“We tested three copper-resistant strains and one copper-sensitive strain,” said Zhu. Copper-resistant strains are lineages of bacteria that have been exposed to copper for several generations, long enough for the cells to develop genetic resistance to its antimicrobial effects. Copper-sensitive strains, by contrast, have never been exposed to copper and are much more susceptible to the toxicity of oxidation.

The researchers placed small samples of each of the Salmonella strains onto the copper alloys, and stored them at different conditions to simulate different types of food processing environments in which the bacteria might exist.

“Salmonella can be a problem in dry foods and wet foods,” Ravishankar said.

Dry foods include products such as peanut butter, almond products and chocolate, while wet foods include vegetables such as tomatoes, lettuce and spinach, milk and other dairy products and anything processed in a wet environment.

Salmonella survived for longer in the simulated wet conditions than in dry conditions, Zhu said. In addition, “copper resistant strains under dry conditions only survive for about 15 minutes – just about five minutes longer than the sensitive strain.”

In dry conditions, oxidation occurs more quickly because the copper in the surface comes into contact with oxygen in the air.

The researchers further tested how well the bacteria would survive in a nutrient-rich medium versus in a non-nutrient medium. “The rich medium can protect the cells from the copper,” said Ravishankar. “We saw survival on the nutrient-rich medium initially, but soon the cells started to die off because of nutrient depletion.”

The researchers also saw that Salmonella cells on alloys with high copper concentrations began to die out much faster than those on surfaces with lower copper concentrations.

“For the highest copper concentration Salmonella cells die off in under 30 minutes,” said Zhu. “But for the other alloys containing lower copper concentrations, the bacteria can survive up to two hours.”

Sadhana Ravishankar, an assistant professor in the UA department of veterinary science and microbiology.

Photo by Beatriz Verdugo/UANews

This is still much less than the two weeks survival achieved by Salmonella on stainless steel, leading the researchers to their conclusion: Copper alloys may be more hygienic surfaces for food processing and preparation than stainless steel.

Ravishankar said she would like to do further tests to see if organic materials on a food contact surface, such as crumbs wedged in cracks or leftover protein residues or grease from oils, could change the effectiveness of copper alloys as antimicrobial agents.

“In a food processing environment, there are going to be hard-to-reach areas where you can still have food particles,” said Ravishankar. “We want to see if the presence of food particles or some kind of organic matter on the copper surfaces changes the efficacy of the copper alloy. Does it become less effective, or is it equally effective?”

Using pure copper is not currently an option, Ravishankar said, due to the high cost of pure copper, and also due to as-yet unresolved concerns that high concentrations of copper residues could potentially have toxic effects on humans as well, if they were ingested.

In the meantime, while using copper alloys as cooking surfaces instead of stainless steel may be slightly more costly, “it will be worthwhile,” Ravishankar said. The high antimicrobial potency of copper alloys, she said, has the potential to significantly reduce cases of food poisoning.

Ravishankar’s study was funded by the International Copper Association, with preliminary research supported by Ravishankar’s start-up funds from the UA College of Agriculture and Life Sciences.


Contacts and sources:
Inside Science TV (ISTV)

University of Arizona 

Vitamin C Kills Drug-Resistant Tuberculosis

In a striking, unexpected discovery, researchers at Albert Einstein College of Medicine of Yeshiva University have determined that vitamin C kills drug-resistant tuberculosis (TB) bacteria in laboratory culture. The finding suggests that vitamin C added to existing TB drugs could shorten TB therapy, and it highlights a new area for drug design. The study was published today in the online journal Nature Communications.

Dr. William Jacobs, Jr. has determined that vitamin C kills drug-resistant tuberculosis (TB) bacteria in laboratory culture. The paper was published online May 21, 2013 in Nature Communications. Dr. Jacobs is professor of microbiology & immunology and of genetics at Einstein. Dr. Jacobs is also a Howard Hughes Medical Institute investigator. See accompanying release.

Credit: Albert Einstein College of Medicine

TB is caused by infection with the bacterium M. tuberculosis. In 2011, TB sickened some 8.7 million people and took some 1.4 million lives, according to the World Health Organization. Infections that fail to respond to TB drugs are a growing problem: About 650,000 people worldwide now have multi-drug-resistant TB (MDR-TB), 9 percent of whom have extensively drug-resistant TB (XDR-TB).TB is especially acute in low and middle income countries, which account for more than 95 percent of TB-related deaths, according to the World Health Organization.

The Einstein discovery arose during research into how TB bacteria become resistant to isoniazid, a potent first-line TB drug. The lead investigator and senior author of the study was William Jacobs, Jr. Ph.D., professor of microbiology & immunology and of genetics at Einstein. Dr. Jacobs is a Howard Hughes Medical Institute investigator and a recently elected member of the National Academy of Sciences.

Dr. Jacobs and his colleagues observed that isoniazid-resistant TB bacteria were deficient in a molecule called mycothiol. "We hypothesized that TB bacteria that can't make mycothiol might contain more cysteine, an amino acid," said Dr. Jacobs. "So, we predicted that if we added isoniazid and cysteine to isoniazid-sensitive M. tuberculosis in culture, the bacteria would develop resistance. Instead, we ended up killing off the culture— something totally unexpected."

The Einstein team suspected that cysteine was helping to kill TB bacteria by acting as a "reducing agent" that triggers the production of reactive oxygen species (sometimes called free radicals), which can damage DNA.

"To test this hypothesis, we repeated the experiment using isoniazid and a different reducing agent— vitamin C," said Dr. Jacobs. "The combination of isoniazid and vitamin C sterilized the M. tuberculosis culture. We were then amazed to discover that vitamin C by itself not only sterilized the drug-susceptible TB, but also sterilized MDR-TB and XDR-TB strains."

To justify testing vitamin C in a clinical trial, Dr. Jacobs needed to find the molecular mechanism by which vitamin C exerted its lethal effect. More research produced the answer: Vitamin C induced what is known as a Fenton reaction, causing iron to react with other molecules to create reactive oxygen species that kill the TB bacteria.

"We don't know whether vitamin C will work in humans, but we now have a rational basis for doing a clinical trial," said Dr. Jacobs. "It also helps that we know vitamin C is inexpensive, widely available and very safe to use. At the very least, this work shows us a new mechanism that we can exploit to attack TB."

Contacts and sources:
Kim Newman
Albert Einstein College of Medicine


The paper is titled, "Mycobacterium tuberculosis is extraordinarily sensitive to killing by a vitamin C-induced Fenton reaction." The other contributors are Catherine Vilcheze, Ph.D., Travis Hartman and Brian Weinrick, Ph.D., all at Einstein.

The study was supported by a grant (AI26170) from National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health.

The authors declare no conflict of interest.

About Drug-Resistant TB:  Multi-drug-resistant TB (MDR-TB): TB that does not respond to isoniazid and rifampicin, the two most potent anti-TB drugs.  Extensively drug-resistant TB (XDR-TB): TB that is resistant to rifampicin and isoniazid, as well as to any member of the quinolone family of antibiotics and at least one of four second-line injectable anti-TB drugs.

NASA To Explore Sun's Million-Degree Outer Atmosphere That Drives The Solar Wind

The time draws near. NASA is getting ready to launch a new mission, a mission to observe a largely unexplored region of the solar atmosphere that powers its dynamic million-degree outer atmosphere and drives the solar wind.

Credit:  NASA

In late June 2013, the Interface Region Imaging Spectrograph, or IRIS, will launch from Vandenberg Air Force Base, Calif. IRIS will advance our understanding of the interface region, a region in the lower atmosphere of the sun where most of the sun’s ultraviolet emissions are generated. Such emissions impact the near-Earth space environment and Earth’s climate.

The interface region lies between the sun’s 11,000-degree Fahrenheit, white-hot, visible surface, the photosphere, and the much hotter multi-million-degree upper corona. Interactions between the violently moving plasma and the sun’s magnetic field in this area may be the source of the energy that heats the corona to some hundreds and occasionally thousands of times hotter than the sun's surface.

IRIS will orbit Earth and use its ultraviolet telescope to obtain high-resolution solar images and spectra. IRIS observations along with advanced computer models will deepen our understanding of how heat and energy move through the lower atmosphere of the sun and other sun-like stars.

For more information about NASA's IRIS mission, please visit:
http://www.nasa.gov/iris


Contacts and sources:
Karen C. Fox
NASA's Goddard Space Flight Center, Greenbelt, Md.

Soft Matter Offers New Ways To Study How Ordered Materials Arrange Themselves

A fried breakfast food popular in Spain provided the inspiration for the development of doughnut-shaped droplets that may provide scientists with a new approach for studying fundamental issues in physics, mathematics and materials.

The doughnut-shaped droplets, a shape known as toroidal, are formed from two dissimilar liquids using a simple rotating stage and an injection needle. About a millimeter in overall size, the droplets are produced individually, their shapes maintained by a surrounding springy material made of polymers. Droplets in this toroidal shape made of a liquid crystal – the same type of material used in laptop displays – may have properties very different from those of spherical droplets made from the same material.

A toroidal droplet made of a nematic liquid crystal material is shown inside a polymeric material. About a millimeter in overall size, the droplets are produced individually, their shapes maintained by the surrounding springy material made of polymers.

Credit: Georgia Tech Photo: Gary Meek

While researchers at the Georgia Institute of Technology don't have a specific application for the doughnut-shaped droplets yet, they believe the novel structures offer opportunities to study many interesting problems, from looking at the properties of ordered materials within these confined spaces to studying how geometry affects how cells behave.

"Our experiments provide a fresh approach to the way that people have been looking at these kinds of problems, which is mainly theoretical. We are doing experiments with toroids whose geometry can be precisely controlled in the lab," said Alberto Fernandez-Nieves, an assistant professor in the Georgia Tech School of Physics. "This work opens up a new way to experimentally look at problems that nobody has been able to study before. The properties of toroidal surfaces are very different, from a general point of view, from those of spherical surfaces."

Development of these "stable nematic droplets with handles" was described May 20 in the early edition of the journal Proceedings of the National Academy of Sciences (PNAS). The research has been sponsored by the National Science Foundation (NSF), and also involves researchers at the Lorentz Institute for Theoretical Physics at Leiden University in The Netherlands and at York University in the United Kingdom.

Droplets normally form spherical shapes to minimize the surface area required to contain a given volume of liquid. Though they appear to be simple, when an ordered material like a crystal or a liquid crystal lives on the surface of a sphere, it provides interesting challenges to mathematicians and theoretical physicists.

A physicist who focuses on soft condensed matter, Fernandez-Nieves had long been interested in the theoretical aspects of curved surfaces. Working with graduate research assistant Ekapop Pairam and postdoctoral fellow Jayalakshmi Vallamkondu, he wanted to extend the theoretical studies into the experimental world for a system of toroidal shapes. 

Georgia Tech assistant professor Alberto Fernandez-Nieves examines the experimental setup used to create toroidal droplets of nematic liquid crystal materials. The injection needle is shown above the cuvette containing the polymeric material, which rests on the rotation stage.

Credit: Georgia Tech Photo: Gary Meek

But could doughnut-shaped droplets be made in the lab?

The partial answer came from churros Fernandez-Nieves ate as a child growing up in Spain. These "Spanish doughnuts" – actually spirals – are made by injecting dough into hot oil while the dough is spun and fried.

In the lab at a much smaller size scale, the researchers found they could use a similar process with two immiscible liquids such as glycerine or water and oil, a needle and a magnetically-controlled rotating stage. A droplet of glycerine is injected into the rotating stage containing the oil. In certain conditions, a jet forms at the needle, which closes up into a torus because of the imposed rotation.

"You can control the two relevant curvatures of the torus," explained Fernandez-Nieves. "You can control how large it is because you can move the needle with respect to the rotation axis. You can also infuse more volume to make the torus thicker."

If the stage is then turned off, however, the drop of glycerine quickly loses its doughnut shape as surface tension forces it to become a traditional spherical droplet. To maintain the toroidal shape, Fernandez-Nieves and his collaborators replace the surrounding oil with a springy polymeric material; the springy character of this material provides a force that can overcome surface tension forces.

"When you are making the toroid, the forces on the needle are large enough that the surrounding material behaves as a fluid," he explained. "Once you stop, the elasticity of the outside fluid overcomes surface tension and that freezes the structure in place."

The researchers have been using the doughnut shapes to study how liquid crystal materials, which are well known for their applications in laptop displays, organize inside the torus. These materials have degrees of order beyond those of simple liquids such as water. For these materials, the toroidal shape provides a new set of study opportunities from both theoretical and experimental perspectives.

"This changes how you think about a liquid inside a container," said Fernandez-Nieves. "The materials will still adopt the shape of the container, but its energy will be different depending on the shape. The materials feel distortions and will try to minimize them. In a given shape, the molecules in these materials will rearrange themselves to minimize these distortions."

Among the surprises is that the nematic droplets created with toroidal shapes become chiral, that is, they adopt a certain twisting direction and break their mirror symmetry.

"In our case, the materials we are using are not chiral under normal circumstances," he noted. "This was a surprise to us, and it has to do with how we are confining the molecules." 

Georgia Tech graduate research assistant Ekapop Pairam examines the experimental setup used to create toroidal droplets of nematic liquid crystal materials. The injection needle is shown above the cuvette containing the polymeric material, which rests on the rotation stage.

Credit: Georgia Tech Photo: Gary Meek

Beyond looking at the dynamics of creating the droplets and how ordered materials behave when the torus transforms into a sphere, Fernandez-Nieves and colleagues are also exploring potential biological applications, applying electrical fields to the droplets, and sharing the unique structures with scientists at other institutions.

"This is the first time that stable nematic droplets have been generated with handles, and we have exploited that to look at the nematic organization inside those spaces," said Fernandez-Nieves. "Our experiments open up a versatile new approach for generating handled droplets made of an ordered material that can self-assemble into interesting and unexpected structures when confined to these non-spherical spaces. Now that theoreticians realize we can generate and study these systems, there may be much more development in this area."

Contacts and sources:
John Toon
Georgia Institute of Technology

In addition to those already mentioned, the paper's authors included V. Koning, B.C. van Zuiden and V. Vitelli from Leiden University, M.A. Bates from the University of York in the United Kingdom, and P.W. Ellis from Georgia Tech.

The research described here has been sponsored by the National Science Foundation under CAREER award DMR-0847304. The findings and conclusions are those of the authors and do not necessarily represent the official views of the National Science Foundation.

Citation: E. Pairam, et al., "Stable nematic droplets with handles," (Proceedings of the National Academy of Sciences, 2013)

Early-Life Traffic-Related Air Pollution Exposure Linked To Hyperactivity

Early-life exposure to traffic-related air pollution was significantly associated with higher hyperactivity scores at age 7, according to new research from the University of Cincinnati (UC) and Cincinnati Children's Hospital Medical Center.

The research is detailed in a study being published Tuesday, May 21, inEnvironmental Health Perspectives, a peer-reviewed open access journal published by the National Institute of Environmental Health Sciences, an institute within the National Institutes of Health (NIH).

The research was conducted by faculty members from the UC College of Medicine's Department of Environmental Health in collaboration with Cincinnati Children's. Nicholas Newman, DO, director of the Pediatric Environmental Health and Lead Clinic at Cincinnati Children's, was the study's first author.

"There is increasing concern about the potential effects of traffic-related air pollution on the developing brain," Newman says. "This impact is not fully understood due to limited epidemiological studies.

"To our knowledge, this is the largest prospective cohort with the longest follow-up investigating early life exposure to traffic-related air pollution and neurobehavioral outcomes at school age." Scientists believe that early life exposures to a variety of toxic substances are important in the development of problems later in life.

Newman and his colleagues collected data on traffic-related air pollution (TRAP) from the Cincinnati Childhood Allergy and Air Pollution Study (CCAAPS), a long-term epidemiological study examining the effects of traffic particulates on childhood respiratory health and allergy development. Funded by the National Institute of Environmental Health Sciences, CCAAPS is led by Grace LeMasters, PhD, of the environmental health department. Study participants—newborns in the Cincinnati metropolitan area from 2001 through 2003—were chosen based on family history and their residence being either near or far from a major highway or bus route.

Children were followed from infancy to age 7, when parents completed the Behavioral Assessment System for Children, 2nd Edition (BASC-2), assessing attention deficit hyperactivity disorder (ADHD) and related symptoms including attention problems, aggression, conduct problems and atypical behavior. Of the 762 children initially enrolled in the study, 576 were included in the final analysis at 7 years of age.

Results showed that children who were exposed to the highest third amount of TRAP during the first year of life were more likely to have hyperactivity scores in the "at risk" range when they were 7 years old. The "at risk" range for hyperactivity in children means that they need to be monitored carefully because they are at risk for developing clinically important symptoms.

"Several biological mechanisms could explain the association between hyperactive behaviors and traffic-related air pollution," Newman says, including narrowed blood vessels in the body and toxicity in the brain's frontal cortex.

Newman notes that the higher air pollution exposure was associated with a significant increase in hyperactivity only among those children whose mothers had greater than a high school education. Mothers with higher education may expect higher achievement, he says, affecting the parental report of behavioral concerns.

"The observed association between traffic-related air pollution and hyperactivity may have far-reaching implications for public health," Newman says, noting that studies have shown that approximately 11 percent of the U.S. population lives within 100 meters of a four-lane highway and that 40 percent of children attend school within 400 meters of a major highway.

"Traffic-related air pollution is one of many factors associated with changes in neurodevelopment, but it is one that is potentially preventable."

LeMasters, Patrick Ryan, PhD, Linda Levin, PhD, David Bernstein, MD, Gurjit Khurana Hershey, MD, PhD, James Lockey, PhD, Manuel Villareal, MD, Tiina Reponen, PhD, Sergey Grinshpun, PhD, Heidi Sucharew, PhD, and Kim Dietrich, PhD, were co-authors of the study.

Funding was provided by NIEHS and the National Institute for Occupational Safety and Health (NIOSH).


Contacts and sources:
Keith Herrell
University of Cincinnati Academic Health Center

Making Gold Green: New Non-Toxic Method For Mining Gold

Scientists launch ‘nano gold rush’ by replacing cyanide with cornstarch.
Northwestern University scientists have struck gold in the laboratory. They have discovered an inexpensive and environmentally benign method that uses simple cornstarch -- instead of cyanide -- to isolate gold from raw materials in a selective manner.

This green method extracts gold from crude sources and leaves behind other metals that are often found mixed together with the crude gold. The new process also can be used to extract gold from consumer electronic waste.

A modern day gold rush! A new method developed at Northwestern bypasses the use of toxic cyanide for gold purification by using an eco-friendly sugar (cyclodextrin) derived from starch. 

Illustration by Aleksandr Bosoy.

Current methods for gold recovery involve the use of highly poisonous cyanides, often leading to contamination of the environment. Nearly all gold-mining companies use this toxic gold leaching process to sequester the precious metal.

“The elimination of cyanide from the gold industry is of the utmost importance environmentally,” said Sir Fraser Stoddart, the Board of Trustees Professor of Chemistry in the Weinberg College of Arts and Sciences. “We have replaced nasty reagents with a cheap, biologically friendly material derived from starch.”

Sir Fraser’s team discovered the process by accident, using simple test tube chemistry. A series of rigorous follow-up investigations provided evidence for the competitive strength of the new procedure.

The findings are published today (May 14) in the online journalNature Communications.

Zhichang Liu, a postdoctoral fellow in Stoddart’s lab and first author of the paper, took two test tubes containing aqueous solutions -- one of the starch-derived alpha-cyclodextrin, the other of a dissolved gold (Au) salt (called aurate) -- and mixed them together in a beaker at room temperature.

Liu was trying to make an extended, three-dimensional cubic structure, which could be used to store gases and small molecules. Unexpectedly, he obtained needles, which formed rapidly upon mixing the two solutions.

“Initially, I was disappointed when my experiment didn’t produce cubes, but when I saw the needles, I got excited,” Liu said. “I wanted to learn more about the composition of these needles.”

“Nature decided otherwise,” said Stoddart, a senior author of the paper. “The needles, composed of straw-like bundles of supramolecular wires, emerged from the mixed solutions in less than a minute.”

After discovering the needles, Liu screened six different complexes -- cyclodextrins composed of rings of six (alpha), seven (beta) and eight (gamma) glucose units, each combined with aqueous solutions of potassium tetrabromoaurate (KAuBr4) or potassium tetrachloroaurate (KAuCl4).

He found that it was alpha-cyclodextrin, a cyclic starch fragment composed of six glucose units, that isolates gold best of all.

“Alpha-cyclodextrin is the gold medal winner,” Stoddart said. “Zhichang stumbled on a piece of magic for isolating gold from anything in a green way.”

Alkali metal salt waste from this new method is relatively environmentally benign, Stoddart said, while waste from conventional methods includes toxic cyanide salts and gases. The Northwestern procedure is also more efficient than current commercial processes.

The supramolecular nanowires, each 1.3 nanometers in diameter, assemble spontaneously in a straw-like manner. In each wire, the gold ion is held together in the middle of four bromine atoms, while the potassium ion is surrounded by six water molecules; these ions are sandwiched in an alternating fashion by alpha-cyclodextrin rings. Around 4,000 wires are bundled parallel to each other and form individual needles that are visible under an electron microscope.

“There is a lot of chemistry packed into these nanowires,” Stoddart said. “The elegance of the composition of single nanowires was revealed by atomic force microscopy, which throws light on the stacking of the individual donut-shaped alpha-cyclodextrin rings.”

The atomic detail of the single supramolecular wires and their relative disposition within the needles was uncovered by single crystal X-ray crystallography.

The research -- a prime example of serendipity at work, brought to fruition by contemporary fundamental science -- is poised to find technological application. This basic science has been forged by the team into a practical labscale process for the isolation of gold from scrap alloys.

The Defense Threat Reduction Agency and the National Science Foundation supported the research.

Contacts and sources: 

Megan Fellman

Northwestern University 

The paper is titled “Selective isolation of gold facilitated by second-sphere coordination with α-cyclodextrin.” In addition to Stoddart and Liu, the other authors of the paper are Marco Frasconi, Juying Lei, Zachary J. Brown, Zhixue Zhu, Dennis Cao, Julien Iehl, Guoliang Liu, Albert C. Fahrenbach, Omar K. Farha, Joseph T. Hupp and Chad A. Mirkin, all from Northwestern, and Youssry Y. Botros of Intel Labs.