How did the equatorial ridge on Saturn's moon Iapetus form?

Handheld plasma flashlight rids skin of notorious pathogens

A group of Chinese and Australian scientists have developed a handheld, battery-powered plasma-producing device that can rid skin of bacteria in an instant.

The device could be used in ambulance emergency calls, natural disaster sites, military combat operations and many other instances where treatment is required in remote locations. The plasma flashlight, presented today, 5 April, in IOP Publishing's Journal of Physics D: Applied Physics is driven by a 12 V battery and doesn't require any external generator or wall power; it also doesn't require any external gas feed or handling system. In the experiment, the plasma flashlight effectively inactivated a thick biofilm of one of the most antibiotic- and heat-resistant bacteria, Enterococcus faecalis – a bacterium which often infects the root canals during dental treatments.

The biofilms were created by incubating the bacteria for seven days. The biofilms were around 25 micrometres thick and consisted of 17 different layers of bacteria. Each one was treated for five minutes with the plasma flashlight and then analysed to see how much of the bacteria survived. Results showed that the plasma not only inactivated the top layer of cells, but penetrated deep into the very bottom of the layers to kill the bacteria.

Co-author of the study, Professor Kostya (Ken) Ostrikov, from the Plasma Nanoscience Centre Australia, CSIRO Materials Science and Engineering, said: "The bacteria form thick biofilms, which makes them enormously resistant against inactivation which is extremely difficult to implement. High temperatures are commonly used but they would obviously burn our skin.

"In this study we chose an extreme example to demonstrate that the plasma flashlight can be very effective even at room temperature. For individual bacteria, the inactivation time could be just tens of seconds."

Plasma – the fourth state of matter in addition to solids, liquids and gases – has previously shown its worth in the medical industry by effectively killing bacteria and viruses on the surface of the skin and in water.

Although the exact mechanism behind the anti-bacterial effect of plasma is largely unknown, it is thought that reactions between the plasma and the air surrounding it create a cocktail of reactive species that are similar to the ones found in our own immune system.

The researchers ran an analysis to see what species were present in the plasma and found that highly-reactive nitrogen- and oxygen-related species dominated the results. Ultraviolet radiation has also been theorised as a reason behind plasma's success; however, this was shown to be low in the jet created by the plasma flashlight, adding to the safety aspect of the device. The temperature of the plume of plasma in the experiments was between 20-230C, which is very close to room temperature and therefore prevents any damage to the skin. The device itself is fitted with resistors to stop it heating up and making it safe to touch.

"The device can be easily made and costs less than 100 US dollars to produce. Of course, some miniaturisation and engineering design may be needed to make it more appealing and ready for commercialisation," Ostrikov continued. The device was created by an international team of researchers from Huazhong University of Science and Technology, CSIRO Materials Science and Engineering, The University of Sydney and the City University of Hong Kong.

From Thursday 5 April, this paper can be downloaded from http://iopscience.iop.org/0022-3727/45/16/165205

http://www.eurekalert.org/pub_releases/2012-04/uoea-efp032812.php

Eating flavonoids protects men against Parkinson's disease

Men who eat flavonoid-rich foods such as berries, tea, apples and red wine significantly reduce their risk of developing Parkinson's disease, according to new research by Harvard University and the University of East Anglia (UEA).

Published today in the journal Neurology ®, the findings add to the growing body of evidence that regular consumption of some flavonoids can have a marked effect on human health. Recent studies have shown that these compounds can offer protection against a wide range of diseases including heart disease, hypertension, some cancers and dementia. This latest study is the first study in humans to show that flavonoids can protect neurons against diseases of the brain such as Parkinson's.

Around 130,000 men and women took part in the research. More than 800 had developed Parkinson's disease within 20 years of follow-up. After a detailed analysis of their diets and adjusting for age and lifestyle, male participants who ate the most flavonoids were shown to be 40 per cent less likely to develop the disease than those who ate the least. No similar link was found for total flavonoid intake in women.

The research was led by Dr Xiang Gao of Harvard School of Public Health in collaboration with Prof Aedin Cassidy of the Department of Nutrition, Norwich Medical School at UEA. "These exciting findings provide further confirmation that regular consumption of flavonoids can have potential health benefits," said Prof Cassidy. "This is the first study in humans to look at the associations between the range of flavonoids in the diet and the risk of developing Parkinson's disease and our findings suggest that a sub-class of flavonoids called anthocyanins may have neuroprotective effects."

Prof Gao said: "Interestingly, anthocyanins and berry fruits, which are rich in anthocyanins, seem to be associated with a lower risk of Parkinson's disease in pooled analyses. Participants who consumed one or more portions of berry fruits each week were around 25 per cent less likely to develop Parkinson's disease, relative to those who did not eat berry fruits. Given the other potential health effects of berry fruits, such as lowering risk of hypertension as reported in our previous studies, it is good to regularly add these fruits to your diet."

Flavonoids are a group of naturally occurring, bioactive compunds found in many plant-based foods and drinks. In this study the main protective effect was from higher intake of anthocyanins, which are present in berries and other fruits and vegetables including aubergines, blackcurrants and blackberries. Those who consumed the most anthocyanins had a 24 per cent reduction in risk of developing Parkinson's disease and strawberries and blueberries were the top two sources in the US diet.

The findings must now be confirmed by other large epidemiological studies and clinical trials.

Parkinson's disease is a progresssive neurological condition affecting one in 500 people, which equates to 127,000 people in the UK. There are few effective drug therapies available.

Dr Kieran Breen, director of research at Parkinson's UK said: "This study raises lots of interesting questions about how diet may influence our risk of Parkinson's and we welcome any new research that could potentially lead to prevention. "While these new results look interesting there are still a lot of questions to answer and much more research to do before we really know how important diet might be for people with Parkinson's."

'Habitual intake of dietary flavonoids and risk of Parkinson's disease' by X Gao (Harvard), A Cassidy (UEA), M Schwarzschild (Massachusetts General Hospital), E Rimm (Harvard) and A Ascherio (Harvard) is published on April 4 by Neurology ® – the medical journal of the American Academy of Neurology.

http://www.eurekalert.org/pub_releases/2012-04/iofs-gif040412.php

Glycemic index foods at breakfast can control blood sugar throughout the day

Eating foods at breakfast that have a low glycemic index may help prevent a spike in blood sugar throughout the morning and after the next meal of the day, researchers said at the Institute of Food Technologists' Wellness 12 meeting.

These breakfast foods also can increase feelings of satiety and fullness and may make people less likely to overeat throughout the day, acdcording to presentations Wednesday by Kantha Shelke, Ph.D., principal, Corvus Blue LLC, and Richard Mattes, M.P.H., R.D., distinguished professor of foods and nutrition at Purdue University.

The glycemic index ranks foods on the extent to which they raise blood sugar levels after eating. Foods with a high index are rapidly digested and result in high fluctuations in blood sugar levels. Foods with a low glycemic index produce gradual rises in blood sugar and insulin levels and are considered healthier, especially for people with diabetes.

Mattes' research specifically focused on the advantages of having almonds, a low glycemic index food, with the morning meal. In his study, published last year in the Journal of Nutrition and Metabolism, participants who ate a breakfast containing whole almonds experienced longer feelings of fullness and had lower blood glucose concentrations after breakfast and lunch, compared to those who did not have a low-glycemic breakfast.

When a low glycemic food is added to the diet, people spontaneously choose to eat less at other times throughout the day. Mattes added that while the calories need to be taken into consideration as part of a person's overall diet, almonds can be incorporated in moderate amounts without an effect on body weight.

Both Mattes and Shelke stressed the importance of eating a healthy, low-glycemic breakfast in maintaining a healthy weight and blood sugar levels. A 2009 study found that about 30 percent of people skip breakfast one to three times per week. Among those who eat breakfast, cold cereal is the most popular (83 percent), followed by eggs (71 percent). In addition to low glycemic index, Dr. Shelke said the ideal breakfast for consumers has these attributes:

Savory	Satiates quickly so less is consumed
Portable	Affordable for the whole family to eat every day
Pleasing texture	Non-fried
Fills you up for extended periods of time	Delicious without making you feeling guilty

"This is a very tall order for food product manufacturers," Shelke said. "It takes a lot of skill and understanding."

While it may present challenges for food manufacturers, it is well worth it to develop these products because of the prevalence of diabetes and pre-diabetes in the United States and beyond. It is estimated that by 2030, more than 16 percent of the global population will have a blood sugar problem.

"Most of the risk factors are things that can be managed and modified," Shelke said. "We can reverse pre-diabetes and prevent it from becoming diabetes. Food has become the reason for what's ailing us, but it can actually be a solution in a number of different ways."

http://www.eurekalert.org/pub_releases/2012-04/niom-sgg040412.php

Spontaneous gene glitches linked to autism risk with older dads

Non-inherited mutations spotlight role of environment – NIH-supported study, consortium

Researchers have turned up a new clue to the workings of a possible environmental factor in autism spectrum disorders (ASDs): fathers were four times more likely than mothers to transmit tiny, spontaneous mutations to their children with the disorders. Moreover, the number of such transmitted genetic glitches increased with paternal age. The discovery may help to explain earlier evidence linking autism risk to older fathers.

The results are among several from a trio of new studies, supported in part by the National Institutes of Health, finding that such sequence changes in parts of genes that code for proteins play a significant role in ASDs. One of the studies determined that having such glitches boosts a child's risk of developing autism five to 20 fold.

Taken together, the three studies represent the largest effort of its kind, drawing upon samples from 549 families to maximize statistical power. They reveal sporadic mutations widely distributed across the genome, sometimes conferring risk and sometimes not. While the changes identified don't account for most cases of illness, they are providing clues to the biology of what are likely multiple syndromes along the autism spectrum.

"These results confirm that it's not necessarily the size of a genetic anomaly that confers risk, but its location – specifically in biochemical pathways involved in brain development and neural connections. Ultimately, it's this kind of knowledge that will yield potential targets for new treatments," explained Thomas, R. Insel, M.D., director of the NIH's National Institute of Mental Health (NIMH), which funded one of the studies and fostered development of the Autism Sequencing Consortium, of which all three groups are members.

Multi-site research teams led by Mark Daly, Ph.D., of the Harvard/MIT Broad Institute, Cambridge, Mass., Matthew State, M.D., Ph.D., of Yale University, New Haven, Conn., and Evan Eichler, Ph.D., of the University of Washington, Seattle, report on their findings online April 4, 2012 in the journal Nature.

The study by Daly and colleagues was supported by NIMH – including funding under the American Recovery and Reinvestment Act. The State and Eichler studies were primarily supported by the Simons Foundation Autism Research Initiative. The studies also acknowledge the NIH's National Human Genome Research Institute, National Heart Lung and Blood Institute, and National Institute on Child Health and Human Development and other NIH components.

All three teams sequenced the protein coding parts of genes in parents and an affected child - mostly in families with only one member touched by autism. One study also included comparisons with healthy siblings. Although these protein-coding areas represent only about 1.5 percent of the genome, they harbor 85 percent of disease-causing mutations. This strategy optimized the odds for detecting the few spontaneous errors in genetic transmission that confer autism risk from the "background noise" generated by the many more benign mutations.

Like larger deletions and duplications of genetic material previously implicated in autism and schizophrenia, the tiny point mutations identified in the current studies are typically not inherited in the conventional sense – they are not part of parents' DNA, but become part of the child's DNA. Most people have many such glitches and suffer no ill effects from them. But evidence is building that such mutations can increase risk for autism if they occur in pathways that disrupt brain development. State's team found that 14 percent of people with autism studied had suspect mutations – five times the normal rate. Eichler and colleagues traced 39 percent of such mutations likely to confer risk to a biological pathway known to be important for communications in the brain.

Although Daly and colleagues found evidence for only a modest role of the chance mutations in autism, those pinpointed were biologically related to each other and to genes previously implicated in autism.

The Eichler team turned up clues to how environmental factors might influence genetics. The high turnover in a male's sperm cells across the lifespan increases the chance for errors to occur in the genetic translation process. These can be passed-on to the offspring's DNA, even though they are not present in the father's DNA. This risk may worsen with aging. The researchers discovered a four-fold marked paternal bias in the origins of 51 spontaneous mutations in coding areas of genes that was positively correlated with increasing age of the father. So such spontaneous mutations could account for findings of an earlier study that found fathers of boys with autism were six times - and of girls 17 times - more likely to be in their 40's than their 20's.

"We now have a path forward to capture a great part of the genetic variability in autism - even to the point of being able to predict how many mutations in coding regions of a gene would be needed to account for illness," said Thomas Lehner, Ph.D., chief of the NIMH Genomics Research Branch, which funded the Daly study and helped to create the Autism Sequencing Consortium. "These studies begin to tell a more comprehensive story about the molecular underpinnings of autism that integrates previously disparate pieces of evidence."

References:

Sanders SJ, Murtha MT, Gupta AR, Murdoch JD, Raubeson MJ, Willsey AJ, Ercan-Sencicek AG, DiLullo NM, Parikshak NN, Stein JL, Walker MF, Ober GT, Teran NA, Song Y, El-Fishawy P, Murtha RC, Choi M, Overton JD, Bjornson RD, Carriero NJ, Meyer KA, Bilguvar K, Mane SM, Sestan N, Lifton RP, Günel M, Roeder K, Geschwind DH, Devlin B, State MW. De novo mutations revealed by whole-exome sequencing are strongly associated with autism. April 5, 2012. Nature.

O'Roak BJ, Vives L, Girirajan S, Karakoc E, Krumm N, Coe BP, Levy R, Ko A, Lee C, Smith JD, Turner EH, Stanaway IB, Vernot B, Malig M, Baker C, Reilly B, Akey JM, Borenstein E, Rieder MJ, Nickerson DA, Bernier R, Shendure J, Eichler EE. Sporadic autism exomes reveal a highly interconnected protein network of de novo mutations. Nature. April 5, 2012.

Neale BM, Kou Y, Liu L, Ma'ayan A, Samocha KE, Sabo A, Lin CF, Stevens C, Wang LS, Makarov V, Polak P, Yoon S, Maguire J, Crawford EL, Campbell NG, Geller ET, Valladares O, Schafer C, Liu H, Zhao T, Cai G, Lihm J, Dannenfelser R, Jabado O, Peralta Z, Nagaswamy U, Muzny D, Reid JG, Newsham I, Wu Y, Lewis L, Han Y, Voight BF, Lim E, Rossin E, Kirby A, Flannick J, Fromer M, Shair K, Fennell T, Garimella K, Banks E, Poplin R, Gabriel S, DePristo M, Wimbish JR, Boone BE, Levy SE, Betancur C, Sunyaev S, Boerwinkle E, Buxbaum JD, Cook EH, Devlin B, Gibbs RA, Roeder K, Schellenberg GD, Sutcliffe JS, Daly MJ. Patterns and rates of exonic de novo mutations in autism spectrum disorders. Nature. April 5, 2012.

http://www.eurekalert.org/pub_releases/2012-04/uoma-tp5040412.php

Thawing permafrost 50 million years ago led to global warming events

Researchers propose new mechanism of past global warming

AMHERST, Mass. – In a new study reported in Nature, climate scientist Rob DeConto of the University of Massachusetts Amherst and colleagues elsewhere propose a simple new mechanism to explain the source of carbon that fed a series of extreme warming events about 55 million years ago, the Paleocene-Eocene Thermal Maximum (PETM), and a sequence of similar, smaller warming events afterward.

"The standard hypothesis has been that the source of carbon was in the ocean, in the form of frozen methane gas in ocean-floor sediments," DeConto says. "We are instead ascribing the carbon source to the continents, in polar latitudes where permafrost can store massive amounts of carbon that can be released as CO2 when the permafrost thaws."

The new view is supported by calculations estimating interactions of variables such as greenhouse gas levels, changes in the Earth's tilt and orbit, ancient distributions of vegetation, and carbon stored in rocks and in frozen soil.

While the amounts of carbon involved in the ancient soil-thaw scenarios was likely much greater than today, implications of the study appear dire for the long-term future as polar permafrost carbon deposits have begun to thaw due to burning fossil-fuels, DeConto adds. "Similar dynamics are at play today. Global warming is degrading permafrost in the north polar regions, thawing frozen organic matter, which will decay to release CO2 and methane into the atmosphere. This will only exacerbate future warming in a positive feedback loop."

He and colleagues at Yale, the University of Colorado, Penn State, the University of Urbino, Italy, and the University of Sheffield, U.K., designed an accurate model―elusive up to now―to satisfactorily account for the source, magnitude and timing of carbon release at the PETM and subsequent very warm periods, which now appear to have been triggered by changes in the Earth's orbit.

Earth's atmospheric temperature is a result of energy input from the sun minus what escapes back to space. Carbon dioxide in the atmosphere absorbs and traps heat that would otherwise return to space. The PETM was accompanied by a massive carbon input to the atmosphere, with ocean acidification, and was characterized by a global temperature rise of about 5 degrees C in a few thousand years, the researchers point out. Until now, it has been difficult to account for the massive amounts of carbon required to cause such dramatic global warming events.

To build the new model, DeConto's team used a new, high-precision geologic record from rocks in central Italy to show that the PETM and other hyperthermals occurred during periods when Earth's orbit around the sun was both highly eccentric (non-circular) and oblique (tilted). Orbit affects the amount, location and seasonality of solar radiation received on Earth, which in turn affects the seasons, particularly in polar latitudes, where permafrost and stored carbon can accumulate.

They then simulated climate-ecosystem-soil interactions, accounting for gradually rising greenhouse gases and polar temperatures plus the combined effects of changes in Earth orbit. Their results show that the magnitude and timing of the PETM and subsequent hyperthermals can be explained by the orbitally triggered decomposition of soil organic carbon in the circum-Arctic and Antarctica.

This massive carbon reservoir at the poles "had the potential to repeatedly release thousands of petagrams of carbon to the atmosphere-ocean system once a long-term warming threshold was reached just prior to the PETM," DeConto and colleagues say. Until now, Antarctica, which today is covered by kilometers of ice, has not been appreciated as an important player in such global carbon dynamics.

In the past, "Antarctica and high elevations of the circum-Arctic were suitable locations for massive carbon storage," they add. "During long-term warming, these environments eventually reached a climatic threshold," with permafrost thaw and the sudden release of stored soil carbon triggered during the Earth's highly eccentric orbits coupled with high tilt.

The model described in the paper also provides a mechanism that helps to explain relatively rapid recovery from hyperthermals associated with orbital extremes occurring about every 1.2 million years, which had until now been difficult.

Overall, they conclude, "an orbital-permafrost soil carbon mechanism provides a unifying model accounting for the salient features of the hyperthermals that other previously proposed mechanisms fail to explain." Further, if the analysis is correct and past extreme warm events can be attributed to permafrost loss, it implies that thawing of permafrost in similar environments observed today "will provide a substantial positive feedback to future warming."
http://www.sciencedaily.com/releases/2012/04/120404125355.htm

Potential Method to Control Obesity: Red Wine, Fruit Compound Could Help Block Fat Cell Formation

A compound found in red wine, grapes and other fruits, and similar in structure to resveratrol, is able to block cellular processes that allow fat cells to develop, opening a door to a potential method to control obesity.