Stating that sleep is an essential biological process seems as obvious as saying that the sun rises every morning. Yet, researchers' understanding of the molecular mechanisms underlying the effects of sleep loss is still in its earliest stages. The risk for a host of metabolic disorders, including weight gain, diabetes, obesity, and cardiovascular disease, associated with reduced sleep is driving basic investigations on the topic.In a study published this week in the Proceedings of the National Academy of Sciences, Amita Sehgal, PhD, a professor of Neuroscience at the Perelman School of Medicine at the University of Pennsylvania and a Howard Hughes Medical Institute investigator, along with co-first authors Aalim M. Weljie, PhD, a research assistant professor of Systems Pharmacology and Translational Therapeutics, and Peter Meerlo, PhD, from the University of Groningen, The Netherlands, found common molecules signifying perturbed metabolism in response to sleep restriction in a comprehensive metabolic profiling of blood from both rats and humans. Their findings point to an overall shift in how lipids are metabolized and evidence of systemic oxidative stress due to decreased sleep in both species. Oxidative stress and lipid metabolism are important factors in metabolic diseases, although further work needs to be done to establish a mechanistic link between the markers found and specific diseases, stress the researchers. "One possibility is that sleep drives metabolite clearance and so acts as a reparative process at the metabolic level," says Sehgal. "The impact of sleep restriction on circadian biology is particularly relevant given what we now know about how metabolites also oscillate in humans on a daily basis." Metabolites are chemical intermediates or end products of metabolism, so while they are generated through the breakdown of fats, carbohydrates, and proteins, their function is not restricted to these processes. They also have roles in signaling, regulating enzymatic activity, growth, and development. Of Rats and Humans The team subjected rats and humans to chronic sleep restriction over five days. Sleep restriction, versus sleep deprivation, curtails sleep time, but does not eliminate sleep. "Sleep restriction more closely represents real-world situations in humans and is a condition experienced by millions of people every day," notes Sehgal. In both studies, metabolite levels were compared in blood that was collected following adequate sleep opportunity in rats and humans to establish a baseline and then following restricted sleep. The team then produced a comprehensive metabolite profile from the blood of sleep-restricted rats and humans. Of the 38 metabolites they found to be unique in the sleep-restricted rats, half were known lipids. A majority of the metabolites from the sleep-restricted human participants were also lipid or fatty acid-related compounds. Seven types of a phospholipid called plasmalogens, related to oxidative stress, were elevated in the sleep-restricted rats. Overall, they found a significant shift in lipid metabolism, with sleep restriction, with higher levels of phospholipids in both rats and humans. The team found that some neurotransmitters and gut metabolites (possibly from intestinal microbes) are also altered due to sleep restriction. "While we don't yet know why the lipids are changed in both species, these shifts are very intriguing, given the epidemiological links between restricted sleep and metabolic disorders, such as diabetes, obesity, and metabolomics syndrome," says Weljie. "I'm sure there's a connection." When they compared the list of significantly altered metabolites in rats and humans compared to the baseline before sleep restriction, they found that two metabolites -- oxalic acid and diacylglycerol 36:3 -- were depleted under sleep-restricted conditions and restored after recovery sleep in both species. Oxalic acid is a waste product derived from processing foods in the diet such as plants, primarily from the breakdown of vitamin C and some amino acids. Diacylglycerol is a precursor molecule in the production of triglycerides, a molecule in which most fat is stored in the body, and also has a function in signaling in cells. The researchers suggest that these two molecules could serve as potential biomarkers since they are present in both species. "These cross-species markers are exciting for a couple reasons," adds Weljie. "First, there is a need for quantitative markers of sleep debt and sleep quality, and this approach suggests that metabolites may be useful in this regard. Second, because we found the same metabolites in the humans and rats, it opens the door for us investigate mechanistic questions regarding the metabolic effects of sleep in rats that may have clinical and therapeutic application." Overall, this work provides a potential link between the known pathologies of reduced sleep duration and metabolic dysfunction. "This is consistent with other studies that suggest that one of the functions of sleep is restorative, involving clearance of metabolites in the brain and reinstating an antioxidant balance in peripheral tissues. Sleep loss, on the other hand, induces an oxidative metabolic state," says Sehgal. Namni Goel, Arjun Senguptaa, Matthew S. Kayser, Ted Abel, Morris J. Birnbaum (now with Pfizer, Inc.), and David F. Dinges, all from Penn, are co-authors. The authors thank the subjects who participated in the experiments and the staff of the Division of Sleep and Chronobiology, who helped acquire the material for metabolomic analysis. This research was supported by HHMI, the Department of the Navy Office of Naval Research Award (N00014-11-1-0361), the National Aeronautics and Space Administration (NNX14AN49G, NCC 9-58), the National Institutes of Nursing Research (NR004281), the Defense Advanced Research Projects Agency and the US Army Research Office (W911NF1010093). Story Source: The above story is based on materials provided by Perelman School of Medicine at the University of Pennsylvania. Note: Materials may be edited for content and length. Journal Reference:
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sexta-feira, 13 de fevereiro de 2015
Common biomarkers of sleep debt found in humans, rats
Magnitude of plastic waste going into the ocean calculated: 8 million metric tons of plastic enter the oceans per year
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The 192 countries with a coast bordering the Atlanta, Pacific and Indian oceans, Mediterranean and Black seas produced a total of 2.5 billion metric tons of solid waste. Of that, 275 million metric tons was plastic, and an estimated 8 million metric tons of mismanaged plastic waste entered the ocean in 2010. A plastic grocery bag cartwheels down the beach until a gust of wind spins it into the ocean. In 192 coastal countries, this scenario plays out over and over again as discarded beverage bottles, food wrappers, toys and other bits of plastic make their way from estuaries, seashores and uncontrolled landfills to settle in the world's seas. How much mismanaged plastic waste is making its way from land to ocean has been a decades-long guessing game. Now, the University of Georgia's Jenna Jambeck and her colleagues in the National Center for Ecological Analysis and Synthesis working group have put a number on the global problem. Their study, reported in the Feb. 13 edition of the journal Science, found between 4.8 and 12.7 million metric tons of plastic entered the ocean in 2010 from people living within 50 kilometers of the coastline. That year, a total of 275 million metric tons of plastic waste was generated in those 192 coastal countries. Jambeck, an assistant professor of environmental engineering in the UGA College of Engineering and the study's lead author, explains the amount of plastic moving from land to ocean each year using 8 million metric tons as the midpoint: "Eight million metric tons is the equivalent to finding five grocery bags full of plastic on every foot of coastline in the 192 countries we examined." To determine the amount of plastic going into the ocean, Jambeck "started it off beautifully with a very grand model of all sources of marine debris," said study co-author Roland Geyer, an associate professor with the University of California, Santa Barbara's Bren School of Environmental Science & Management, who teamed with Jambeck and others to develop the estimates. They began by looking at all debris entering the ocean from land, sea and other pathways. Their goal was to develop models for each of these sources. After gathering rough estimates, "it fairly quickly emerged that the mismanaged waste and solid waste dispersed was the biggest contributor of all of them," he said. From there, they focused on plastic. "For the first time, we're estimating the amount of plastic that enters the oceans in a given year," said study co-author Kara Lavender Law, a research professor at the Massachusetts-based Sea Education Association. "Nobody has had a good sense of the size of that problem until now." The framework the researchers developed isn't limited to calculating plastic inputs into the ocean. "Jenna created a framework to analyze solid waste streams in countries around the world that can easily be adapted by anyone who is interested," she said. "Plus, it can be used to generate possible solution strategies." Plastic pollution in the ocean was first reported in the scientific literature in the early 1970s. In the 40 years since, there were no rigorous estimates of the amount and origin of plastic debris making its way into the marine environment until Jambeck's current study. Part of the issue is that plastic is a relatively new problem coupled with a relatively new waste solution. Plastic first appeared on the consumer market in the 1930s and '40s. Waste management didn't start developing its current infrastructure in the U.S., Europe and parts of Asia until the mid-1970s. Prior to that time, trash was dumped in unstructured landfills--Jambeck has vivid memories of growing up in rural Minnesota, dropping her family's garbage off at a small dump and watching bears wander through furniture, tires and debris as they looked for food. "It is incredible how far we have come in environmental engineering, advancing recycling and waste management systems to protect human health and the environment, in a relatively short amount of time," she said. "However, these protections are unfortunately not available equally throughout the world." Some of the 192 countries included in the model have no formal waste management systems, Jambeck said. Solid waste management is typically one of the last urban environmental engineering infrastructure components to be addressed during a country's development. Clean water and sewage treatment often come first. "The human impact from not having clean drinking water is acute, with sewage treatment often coming next," she said. "Those first two needs are addressed before solid waste, because waste doesn't seem to have any immediate threat to humans. And then solid waste piles up in streets and yards and it's the thing that gets forgotten for a while." As the gross national income increases in these countries, so does the use of plastic. In 2013, the most current numbers available, global plastic resin production reached 299 million tons, a 647 percent increase over numbers recorded in 1975. Plastic resin is used to make many one-use items like wrappers, beverage bottles and plastic bags. With the mass increase in plastic production, the idea that waste can be contained in a few-acre landfill or dealt with later is no longer viable. That was the mindset before the onslaught of plastic, when most people piled their waste--glass, food scraps, broken pottery--on a corner of their land or burned or buried it. Now, the average American generates about 5 pounds of trash per day with 13% of that being plastic. But knowing how much plastic is going into the ocean is just one part of the puzzle, Jambeck said. With between 4.8 and 12.7 million metric tons going in, researchers like Law are only finding between 6,350 and 245,000 metric tons floating on the ocean's surface. "This paper gives us a sense of just how much we're missing," Law said, "how much we need to find in the ocean to get to the total. Right now, we're mainly collecting numbers on plastic that floats. There is a lot of plastic sitting on the bottom of the ocean and on beaches worldwide." Jambeck forecasts that the cumulative impact to the oceans will equal 155 million metric tons by 2025. The planet is not predicted to reach global "peak waste" before 2100, according to World Bank calculations. "We're being overwhelmed by our waste," she said. "But our framework allows us to also examine mitigation strategies like improving global solid waste management and reducing plastic in the waste stream. Potential solutions will need to coordinate local and global efforts." |
quinta-feira, 12 de fevereiro de 2015
Warming pushes Western US toward driest period in 1,000 years: Unprecedented Risk of Drought in 21st Century
| Soil moisture 30 cm below ground projected through 2100 for high emissions scenario RCP 8.5. The soil moisture data are standardized to the Palmer Drought Severity Index and are deviations from the 20th century average. During the second half of the 21st century, the U.S. Southwest and Great Plains will face persistent drought worse than anything seen in times ancient or modern, with the drying conditions "driven primarily" by human-induced global warming, a new study predicts. The research says the drying would surpass in severity any of the decades-long "megadroughts" that occurred much earlier during the past 1,000 years -- one of which has been tied by some researchers to the decline of the Anasazi or Ancient Pueblo Peoples in the Colorado Plateau in the late 13th century. Many studies have already predicted that the Southwest could dry due to global warming, but this is the first to say that such drying could exceed the worst conditions of the distant past. The impacts today would be devastating, given the region's much larger population and use of resources. "We are the first to do this kind of quantitative comparison between the projections and the distant past, and the story is a bit bleak," said Jason E. Smerdon, a co-author and climate scientist at the Lamont-Doherty Earth Observatory, part of the Earth Institute at Columbia University. "Even when selecting for the worst megadrought-dominated period, the 21st century projections make the megadroughts seem like quaint walks through the Garden of Eden." "The surprising thing to us was really how consistent the response was over these regions, nearly regardless of what model we used or what soil moisture metric we looked at," said lead author Benjamin I. Cook of the NASA Goddard Institute for Space Studies and the Lamont-Doherty Earth Observatory. "It all showed this really, really significant drying." The new study, "Unprecedented 21st-Century Drought Risk in the American Southwest and Central Plains," will be featured in the inaugural edition of the new online journal Science Advances, produced by the American Association for the Advancement of Science, which also publishes the leading journal Science. Today, 11 of the past 14 years have been drought years in much of the American West, including California, Nevada, New Mexico and Arizona and across the Southern Plains to Texas and Oklahoma, according to the U.S. Drought Monitor, a collaboration of U.S. government agencies. The current drought directly affects more than64 million people in the Southwest and Southern Plains, according to NASA, and many more are indirectly affected because of the impacts on agricultural regions. Shrinking water supplies have forced western states to impose water use restrictions; aquifers are being drawn down to unsustainable levels, and major surface reservoirs such as Lake Mead and Lake Powell are at historically low levels. This winter's snowpack in the Sierras, a major water source for Los Angeles and other cities, is less than a quarter of what authorities call a "normal" level, according to a February report from the Los Angeles Department of Water and Power. California water officials last year cut off the flow of water from the northern part of the state to the south, forcing farmers in the Central Valley to leave hundreds of thousands of acres unplanted. "Changes in precipitation, temperature and drought, and the consequences it has for our society -- which is critically dependent on our freshwater resources for food, electricity and industry -- are likely to be the most immediate climate impacts we experience as a result of greenhouse gas emissions," said Kevin Anchukaitis, a climate researcher at the Woods Hole Oceanographic Institution. Anchukaitis said the findings "require us to think rather immediately about how we could and would adapt." Much of our knowledge about past droughts comes from extensive study of tree rings conducted by Lamont-Doherty scientist Edward Cook (Benjamin's father) and others, who in 2009 created the North American Drought Atlas. The atlas recreates the history of drought over the previous 2,005 years, based on hundreds of tree-ring chronologies, gleaned in turn from tens of thousands of tree samples across the United States, Mexico and parts of Canada. For the current study, researchers used data from the atlas to represent past climate, and applied three different measures for drought -- two soil moisture measurements at varying depths, and a version of the Palmer Drought Severity Index, which gauges precipitation and evaporation and transpiration -- the net input of water into the land. While some have questioned how accurately the Palmer drought index truly reflects soil moisture, the researchers found it matched well with other measures, and that it "provides a bridge between the [climate] models and drought in observations," Cook said. The researchers applied 17 different climate models to analyze the future impact of rising average temperatures on the regions. And, they compared two different global warming scenarios -- one with "business as usual," projecting a continued rise in emissions of the greenhouse gases that contribute to global warming; and a second scenario in which emissions are moderated. By most of those measures, they came to the same conclusions. "The results … are extremely unfavorable for the continuation of agricultural and water resource management as they are currently practiced in the Great Plains and southwestern United States," said David Stahle, professor in the Department of Geosciences at the University of Arkansas and director of the Tree-Ring Laboratory there. Stahle was not involved in the study, though he worked on the North American Drought Atlas. Smerdon said he and his colleagues are confident in their results. The effects of CO2 on higher average temperature and the subsequent connection to drying in the Southwest and Great Plains emerge as a "strong signal" across the majority of the models, regardless of the drought metrics that are used, he said. And, he added, they are consistent with many previous studies. Anchukaitis said the paper "provides an elegant and convincing connection" between reconstructions of past climate and the models pointing to the risk of future drought. Toby R. Ault of Cornell University is a co-author of the study. Funding was provided by the NASA Modeling, Analysis and Prediction Program, NASA Strategic Science, and the U.S. National Science Foundation. |
Pyramid or plate? Explore these healthy diet options
Healthy diets come in all shapes and sizes. Pick one and discover how easy it is to eat healthy.By Mayo Clinic StaffA healthy diet can be illustrated in many ways, but it's often found in the shape of a pyramid. Most people are familiar with MyPyramid developed by the Department of Agriculture, but that's history now. It's been replaced with MyPlate. However, many other healthy diets are still represented by food pyramids. These include the Asian, Latin American, Mediterranean and Vegetarian Food Guide pyramids, as well as the Mayo Clinic Healthy Weight Pyramid, just to name a few. These graphics reinforce the choices that are the foundation of a healthy diet. Pyramid or plate? Explore these healthy diet optionsThese pyramids reflect the same general principles of healthy eating but allow for different food choices.Basic principles of a healthy dietSymbols, such as a pyramid, illustrate how the pieces of a healthy diet fit together. The base of the pyramid is typically made up of foods that should be the bulk of your healthy diet. In contrast, foods you should eat in smaller amounts or less frequently are shown in the smaller sections of the pyramid. The same principle applies to the dinner plate — half of the plate consists of fruits and vegetables, which should be the bulk of your diet. Of course, no single food provides all of the nutrients that your body needs, so the idea is to eat a variety of foods from each group in the proper proportions to get all the necessary nutrients and other substances that promote good health. In addition, most healthy-diet plans emphasize the following:
Variations among healthy diet plansMost healthy diets are built on the same general principles, but there are key differences that reflect dietary preferences, food availability and cultural eating patterns. For example, the Latin American Diet Pyramid might mention tortillas and cornmeal, whereas the Asian Diet Pyramid might include noodles and rice. Other differences include:
Putting the pyramid — or plate — to work for youTo see how your eating habits match up to these healthy-diet plans, keep a food diary for several days. Then compare how much of your diet comes from the various groups. You may be surprised by the results. To eat healthier, start with gradual changes, such as eating more vegetables, fruits and whole grains, and limiting fats and sweets. Here are a few more tips to help you adopt healthier eating habits:
Remember to be creative and go for good taste. A variety of healthy-eating plans are available, so why not try a few on for size? You can explore the world's cuisines and improve your diet at the same time. source : www.mayoclinic.org
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Contraception Could Prevent 15 Million Unwanted Pregnancies Annually
| Fifteen million unwanted pregnancies in 35 low- and middle-income countries could be avoided if women had access to and freedom to use contraception. Cynthia Graber reports. February 12, 2015 By Cynthia Graber It sounds obvious—pregnancies could be avoided by using contraception. But 15 million unwanted pregnancies could be avoided annually in 35 low- and middle-income countries if women did in fact use modern contraception. That’s according to a study in the journal Human Reproduction. [Saverio Bellizzi et al, Underuse of modern methods of contraception: underlying causes and consequent undesired pregnancies in 35 low- and middle-income countries] Unwanted pregnancy has a wide range of serious consequences. Women may have to stop their education or employment. They might pursue unsafe abortions. And they can face disability, disease and death as a result of the pregnancy. source – sciam
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Glowing amino acid lights up growing brain cancer
Uptake of tagged glutamine allows scans to spot tumor changes during treatment2:02pm, February 11, 2015 By injecting the amino acid glutamine that’s been tagged with a tracer compound into patients with brain cancer, scientists have devised a technique that might enable doctors to spot growth of such tumors with high accuracy. Glutamine and glucose provide nourishment for malignant cells in patients with glioma, a cancer of glial cells. These support cells for neurons become ravenous for both nutrients when cancerous, so spotting their high uptake with brain scans could provide a way to monitor the cancer. But glucose is also taken up widely by normal tissues in the brain. In contrast, glutamine is voraciously gobbled up by several cancers including glioma, researchers report in the Feb. 11 Science Translational Medicine. Venneti et al/Science Translational Medicine 2015 Tests in mice with glioma show that a glutamine analog toting a telltale radioactive tracer gets taken up readily by glioma cells but not by healthy cells. The tracer shows up in PET, or positron emission tomography, scans. This allows tumor delineation, scientists from Memorial Sloan Kettering Cancer Center in New York City and elsewhere report. In six glioma patients, brain scans revealed that while aggressive brain tumors took up the tagged glutamine readily, stable tumors did so only minimally, if at all. The imaging technique might enable doctors to more clearly track brain cancer growth, the authors say. |
New alloy of steel is as strong and light as titanium
| The GIFT development could lead to the new steel alloy replacing aluminum in lightweight, fuel-efficient automobiles and aircraft (Photo: Shutterstock) By altering metal alloy at a nanoscale level, researchers at the Graduate Institute of Ferrous Technology (GIFT) at Pohang University of Science and Technology in South Korea have created a new material that has the strength of steel and the lightness of titanium alloy. Made from an amalgam of steel, aluminum, carbon, manganese, and nickel, the new alloy promises to be low-cost and readily available due to its mix of common minerals. Previous research into lightweight steel has focused on mixing in aluminum in varying proportions to attempt to reduce the density, and therefore the weight. Unfortunately, upping the aluminum content in steel also badly affects its ductility (the way that a material behaves under tensile stress) which results in its increasing vulnerability to fracture. In an attempt to rectify this major impediment to producing a practical lightweight steel, the research team at GIFT uniformly distributed nanometer-sized B2 intermetallic compounds (an amalgam of two metals with equal numbers of atoms) in and around the steel grain structure. though incorporating B2 into steel has been tried in the past, it has ordinarily been harmful to the structure. However, by adding nickel to the admixture, the team was able to take advantage of the addition of B2, while also helping to increase the ductility of the steel alloy. As a result of this research, sturdier, lightweight and more ductile steel compounds may be developed, promising to alleviate the age old problem of brittle intermetallic compound alloys. In this vein, the researchers intend to collaborate with POSCO (formerly the Pohang Iron and Steel Company) to trial forge its new alloy later on this year. It is still early days in this research, and no plans have been announced as to whether this will go beyond a trial commercial process level. But the concept of producing a lightweight version of steel using an abundant mineral such as iron – the base component of steel – could open up a raft of possibilities. Not the least of which may be a new era of high-strength, lightweight steels that may one day usurp aluminum in the production of fuel efficient vehicles and other construction systems. Source: Pohang University
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Crystal Pattern Mapping Can Recover Obliterated Serial Numbers in Metals
From NIST Tech Beat: February 11, 2015Contact: Laura Ost Researchers at the National Institute of Standards and Technology (NIST) have demonstrated a technique for mapping deformation in metals that can recover destroyed serial numbers on metal objects such as firearms, a common challenge in forensics. The technique might also meet other forensic needs such as reconstructing vehicle identification numbers or imprints on ammunition casings, the researchers suggest. Law enforcement agencies use serial numbers to track ownership of firearms and build criminal cases. But serial numbers can be removed by scratching, grinding or other methods. Analysts typically try to restore the numbers with acid or electrolytic etching or polishing, because deformed areas behave differently from undamaged material. But these methods don’t always work. As a possible alternative, NIST researchers used a technique called electron backscatter diffraction (EBSD) to read, in the crystal structure pattern, imprints on steel that had been removed by polishing. In EBSD, a scanning electron microscope scans a beam of electrons over the surface of a crystalline material such as a metal. The electrons strike atoms in the target and bounce back. Because the atoms are arranged in a regular pattern, the scattered electrons interact and form patterns that reveal the crystal’s structure on a scale down to tens of nanometers. The more perfect the crystal structure, the stronger and clearer the pattern. Software can then calculate the pattern quality to reveal crystal damage; areas with more damage produce lower quality patterns. In the NIST experiments, described in Forensic Science International,* researchers hammered the letter “X” into a polished stainless steel plate. The letter stamps were as deep as 140 micrometers, meeting federal regulations for firearm serial numbers. The researchers then polished the metal again to remove all visible traces of the letters, and collected the EBSD diffraction patterns and pattern quality data and analyzed them for evidence of the imprints. Ordinary SEM imaging methods revealed very faint outlines of the X stamps in the metal grains. However, pattern quality mapping more clearly revealed the outlines of the Xs, and according to the team, would probably be acceptable for submission as forensic evidence. The latter technique is significantly more sensitive to small amounts of crystal lattice damage. The technique is still experimental, but shows some promise. The NIST team found evidence of metal deformation down to about 760 micrometers below the surface, much deeper than the actual X stamps. Even so, the researchers say it’s not clear whether EBSD pattern quality mapping is more sensitive and/or more effective than conventional techniques for reconstructing serial numbers, or whether EBSD will work in cases of the most extreme destruction. Experimental comparison of the new technique to traditional techniques is under way. Currently, the NIST method is time-consuming: A technician would need three full days to reconstruct an 8-character number. With further development and optimization, such as making pixel sizes larger in the images, recovery time probably could be reduced to about an hour, according to the researchers. The researchers suggest that wide adoption of this technology might enable manufacturers to place “hidden” sub-surface serial numbers on firearms—numbers that would be invisible to criminals but clearly detectable by law enforcement with this new analysis method. The idea of using EBSD to recover firearm serial numbers was first proposed at a conference several years ago by Carl Necker of Los Alamos National Laboratory. *R.M. White and R.R. Keller. Restoration of firearm serial numbers using electron backscatter diffraction (EBSD). Forensic Science International. In press accepted manuscript. Published online Feb. 9, 2015. DOI: http://dx.doi.org/10.1016/j.forsciint.2015.02.003.source : www.nist.gov |
Monitoring epilepsy in the brain with a wireless system
Wed, 02/11/2015 - 12:56pmLaure-Anne Pessina, EPFL
Source: Thinkstock/EPFLThe large majority of the 50 million people around the world who suffer from epilepsy can be treated by anticonvulsant drugs. Yet a handful of patients do not respond to the standard treatment. More and more of them are turning to surgery to give them back a normal life. The principle is to locate, with the help of electrodes, the region in the brain that is the source of the epilepsy and, in the most serious cases, remove it. The current presurgical phase is complex and highly invasive. Patients undergo a cranial operation to have electrodes implanted on the surface of their cortex. Once the wound is closed, the patients must remain in bed in intensive care for several weeks with wires passing through their cranium. The electrodes are connected the entire time to a recording machine, which is used to identify the source of the epilepsy during seizures. Researchers at EPFL are now developing a network of wireless microelectrodes that will monitor the patients' brain activity with great precision, without requiring them to remain confined to their hospital bed. Gürkan Yilmaz presented this research as part of his doctoral thesis, conducted in collaboration with doctors and researchers from Inselspital (University Hospital of Bern). A number of in vivo tests have been carried out successfully. Greater precision and less damage to the brain The new wireless method still needs a cranial operation, but it offers a number of advantages. In addition to suppressing cumbersome wires and sparing patients the ordeal of staying in intensive care during the presurgical phase, it extends the monitoring time, thanks to the reduced risk of infection. The source of the epilepsy can also be identified more precisely. "We are developing electrodes that are less than 100 micrometers in diameter, versus 10 millimeters for electrodes used in traditional intracranial electroencephalograms," says Yilmaz. "As a result, measurements are much more precise, and the fewest possible neurons are removed during the operation. This allows us to minimise the damage that can result from this type of operation." With the new system, which consists of a network of electrodes, a microchip and an antenna, the electric signals are captured and processed under the skin in a miniaturised station. The internal device is powered from the outside by wireless power transfer, more specifically by electromagnetic induction. Thanks to this energy, the internal system can process a large amount of data, and then transfer the results to an external unit. "We could use a mobile phone to receive the data, but for reasons of data security, it is not the preferred method," says Gürkan Yilmaz. At this stage, in vivo tests have been successfully run on laboratory mice. Innovative, less invasive therapies Medical doctors are showing a significant interest in this technology. Claudio Pollo, a neurosurgeon in charge of epilepsy surgery at Bern University Hospital, explains the potential represented by such a system. "We would be able to observe epileptogenesis at the level of a few cells rather than tens of thousands of cells," he notes. "This would enable us to remove smaller epileptogenic zones, and to develop innovative therapies. For example, when a given region cannot be removed, we could deliver electrical stimulation to the lesions to prevent seizures." And this type of surgery produces excellent results. "The recovery rate is nearly 80%, when talking about temporal lobe epilepsy. More and more children are operated on, and this drastically changes their future." In the laboratory, the researchers continue their work. Their goals include adjusting the size of the electrodes so that they can measure the activity of a single neuron. Source: EPFL |
Group Social Activity Keeps People Mentally Sharp
Clubs and parties beat one-on-one encounters for preventing cognitive declineDec 18, 2014 By Erica Westly A BELLO Getty Images Social activity is well known to influence mental health, particularly as people age—but the details behind this phenomenon are unclear. Different types of social interactions may be more or less important, depending on the circumstances. One-on-one relationships, such as those between spouses, may yield specific emotional benefits. When it comes to slowing cognitive decline, however, group interactions have more power, according to a recent study published in Social Science & Medicine. The study analyzed data from more than 3,400 adults aged 50 and older. Subjects who reported high engagement with social groups such as book clubs and community organizations performed better on tests measuring cognitive skills such as working memory. Individual relationships such as friendships, meanwhile, appeared to have no effect on cognitive ability. The mental boost from group activity was also more pronounced with age: group-connected subjects closer to age 50 had the cognitive capacities of someone about five years younger, whereas those near 80 years old were rejuvenated by about 10 years, putting them mentally closer to a 70-year-old. Group relationships require effort to maintain, and they reinforce self-identity, both of which may sharpen thinking skills, says Catherine Haslam, a clinical psychology professor at the University of Queensland in Australia and lead author of the study. Conversely, the ease of interactions with spouses or family members may make them less stimulating. “The difference in terms of keeping mentally active is those group relationships,” Haslam says. source : www.scientificamerican.com |
