Rainbow-catching waveguide could revolutionize energy technologies

By slowing and absorbing certain wavelengths of light, engineers open new possibilities in solar power, thermal energy recycling and stealth technologyMore efficient photovoltaic cells. Improved radar and stealth technology. A new way to recycle waste heat generated by machines into energy.All may be possible due to breakthrough photonics research at the University at Buffalo.The work, published March 28 in the journal Scientific Reports, explores the use of a nanoscale microchip component called a “multilayered waveguide taper array” that improves the chip’s ability to trap and absorb light.Unlike current chips, the waveguide tapers (the thimble-shaped structures pictured above) slow and ultimately absorb each frequency of light at different places vertically to catch a “rainbow” of wavelengths, or broadband light.”We previously predicted the multilayered waveguide tapers would more efficiently absorb light, and now we’ve proved it with these experiments,” says lead researcher Qiaoqiang Gan, PhD, UB assistant professor of electrical engineering. “This advancement could prove invaluable for thin-film solar technology, as well as recycling waste thermal energy that is a byproduct of industry and everyday electronic devices such as smartphones and laptops.”Each multilayered waveguide taper is made of ultrathin layers of metal, semiconductors and/or insulators. The tapers absorb light in metal dielectric layer pairs, the so-called hyperbolic metamaterial. By adjusting the thickness of the layers and other geometric parameters, the tapers can be tuned to different frequencies including visible, near-infrared, mid-infrared, terahertz and microwaves.The structure could lead to advancements in an array of fields.For example, there is a relatively new field of advanced computing research called on-chip optical communication. In this field, there is a phenomenon known as crosstalk, in which an optical signal transmitted on one waveguide channel creates an undesired scattering or coupling effect on another waveguide channel. The multilayered waveguide taper structure array could potentially prevent this.It could also improve thin-film photovoltaic cells, which are a promising because they are less expensive and more flexible that traditional solar cells. The drawback, however, is that they don’t absorb as much light as traditional cells. Because the multilayered waveguide taper structure array can efficiently absorb the visible spectrum, as well as the infrared spectrum, it could potentially boost the amount of energy that thin-film solar cells generate.The multilayered waveguide taper array could help recycle waste heat generated by power plants and other industrial processes, as well as electronic devices such as televisions, smartphones and laptop computers.”It could be useful as an ultra compact thermal-absorption, collection and liberation device in the mid-infrared spectrum,” says Dengxin Ji, a PhD student in Gan’s lab and first author of the paper.It could even be used as a stealth, or cloaking, material for airplanes, ships and other vehicles to avoid radar, sonar, infrared and other forms of detection. …

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New way to filter light: May provide first directional selectivity for light waves

Light waves can be defined by three fundamental characteristics: their color (or wavelength), polarization, and direction. While it has long been possible to selectively filter light according to its color or polarization, selectivity based on the direction of propagation has remained elusive.But now, for the first time, MIT researchers have produced a system that allows light of any color to pass through only if it is coming from one specific angle; the technique reflects all light coming from other directions. This new approach could ultimately lead to advances in solar photovoltaics, detectors for telescopes and microscopes, and privacy filters for display screens.The work is described in a paper appearing this week in the journal Science, written by MIT graduate student Yichen Shen, professor of physics Marin Soljačić, and four others. “We are excited about this,” Soljačić says, “because it is a very fundamental building block in our ability to control light.”The new structure consists of a stack of ultrathin layers of two alternating materials where the thickness of each layer is precisely controlled. “When you have two materials, then generally at the interface between them you will have some reflections,” Soljačić explains. But at these interfaces, “there is this magical angle called the Brewster angle, and when you come in at exactly that angle and the appropriate polarization, there is no reflection at all.”While the amount of light reflected at each of these interfaces is small, by combining many layers with the same properties, most of the light can be reflected away — except for that coming in at precisely the right angle and polarization.Using a stack of about 80 alternating layers of precise thickness, Shen says, “We are able to reflect light at most of the angles, over a very broad band [of colors]: the entire visible range of frequencies.”Previous work had demonstrated ways of selectively reflecting light except for one precise angle, but those approaches were limited to a narrow range of colors of light. The new system’s breadth could open up many potential applications, the team says.Shen says, “This could have great applications in energy, and especially in solar thermophotovoltaics” — harnessing solar energy by using it to heat a material, which in turn radiates light of a particular color. That light emission can then be harnessed using a photovoltaic cell tuned to make maximum use of that color of light. But for this approach to work, it is essential to limit the heat and light lost to reflections, and re-emission, so the ability to selectively control those reflections could improve efficiency.The findings could also prove useful in optical systems, such as microscopes and telescopes, for viewing faint objects that are close to brighter objects — for example, a faint planet next to a bright star. By using a system that receives light only from a certain angle, such devices could have an improved ability to detect faint targets. …

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Workplace flexibility still a myth for most

Workplace flexibility — it’s a phrase that might be appealing to job seekers or make a company look good, but a new study by the Sloan Center on Aging and Work at Boston College shows flexible work options are out of reach for most employees and that when they are offered, arrangements are limited in size and scope.”While large percentages of employers report that they have at least some workplace flexibility, the number of options is usually limited and they are typically not available to the entire workforce,” says Marcie Pitt-Catsouphes, Ph.D., Director of the Sloan Center on Aging and Work at Boston College and one of the researchers of the study. “We’re trying to help employers understand that flexible work initiatives work best if their organizations offer a comprehensive set of options. Employers who implement limited programs might become frustrated if they don’t see the outcomes they had hoped for saying, ‘Gosh, this didn’t help us at all’ or, ‘it didn’t help us with recruitment’ or ‘it didn’t help us with retention.’ In fact, it may not be that the flexible work options didn’t work. Rather, that the companies didn’t offer a sufficient range of options to the employees.”The study, published in the journal, Community, Work, and Family, examined the flexible work arrangements of 545 U.S. employers and found most arrangements center around allowing employees to move where they work and when they report in, but didn’t include reduction of work or temporary leaves from jobs. Additionally, any flexibility options that are available aren’t being made to the majority of a company’s employees.”We should probably set our standards and expectations a little higher,” says Dr. Pitt-Catsouphes. “Business leaders as well as academics have been trying to promote the adoption of quality flexible work initiatives for the past three decades. We have come to realize how important it is for employers to offer different types of flexibilities so that employees and their supervisors have some choice and control over when, where and how much they work. Employers and employees are better able to reap the benefits of workplace flexibility when the initiatives are comprehensive and well aligned with business priorities.”The study, co-authored by Stephen Sweet of Ithaca College, Elyssa Besen of the Center for Disability Research, Lonnie Golden of Penn State Abington along with Boston College’s Pitt-Catsouphes, found only one in five companies offered more than one approach to workplace flexibility, despite the fact that different employees need different options.”What we’re saying is flexibility can work if you make a commitment to making it work,” says Pitt-Catsouphes. …

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Arm Injury Accident at Work Leads to Fine

Home » No Win No Fee » Latest Personal Injury News » 2014 » 3 » Arm Injury Accident at Work Leads to FineArm Injury Accident at Work Leads to FineCEP Ceilings has been hit with a hefty fine following an accident in which an employee’s arm was injured after getting caught in a machine.The worker was operating a amchine at its premises in Stafford last year when his forearm got trapped in its intermeshing metal gears. He subsequently had to undergo skin grafts in order for the wounds to heal.Inspectors from the Health and Safety Executive (HSE) found that the accident came about partly because CEP Ceilings failed to carry out an adequate risk assessment on the site.The HSE also discovered that the company had not implemented a safe system of work, while employees were not monitored sufficiently when they were using machinery.£24,000 FineCEP Ceilings later pleaded guilty to breaching the Health and Safety at Work etc Act 1974 and the Management of Health and Safety at Work Regulations 1999 at Stafford Magistrates’ Court. The company was ordered to pay a £24,000 fine plus £1,194 in costs.Unsafe Methods ‘Existed for Many Years’After the sentence was issued in court, the HSE criticised CEP Ceilings for having adopted an unsafe way of working for a long time.Wayne Owen, an inspector at the watchdog, said procedures that had not been fit for purpose had “existed for many years” and this led to the employee suffering a “painful injury”.”CEP Ceilings [failed] to effectively assess the risk to employees from using and clearing the machine and then prescribe a system of work which kept employees safe,” he commented.”Workers were left to determine their own methods of cleaning machinery.”Mr Owen insisted that employers must implement safe working procedures and ensure members of staff are properly instructed and trained on how to comply with these rules in full.This, he said, can help to manage risks during both production and maintenance activities at premises where industrial machinery is in use.”A robust system to monitor employees also needs to be in place to detect any poor practices,” Mr Owen commented.Related Work Accident in StaffordshireThe case follows another work accident in which Andrew Thomas, an employee at Marling Leek in Staffordshire, also suffered an arm injury after it got caught in an unguarded machine.Mr Thomas subsequently had to undergo five operations, but was left with permanent scars, while the strength and feeling in his arm has been reduced as a result of nerve damage and muscle loss.The HSE was particularly critical of Marling Leek as it had been prosecuted over a previous accident in the past, but had failed to address the problems and carry out an adequate risk assessment throughout the business.Lyn Spooner, an inspector at the HSE, insisted that carrying out a risk assessment is a “vital process to allow a company to identify significant risk and ensure it is complying with relevant statutory provisions”.She added that there is extensive guidance on preventing access to dangerous machine parts in the workplace to enable employers to comply with the law.By Chris StevensonOr Call freephone 0800 884 0321SHARE THIS

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Plankton make scents for seabirds and a cooler planet

The top predators of the Southern Ocean, far-ranging seabirds, are tied both to the health of the ocean ecosystem and to global climate regulation through a mutual relationship with phytoplankton, according to newly published work from the University of California, Davis.When phytoplankton are eaten by grazing crustaceans called krill, they release a chemical signal that calls in krill-eating birds. At the same time, this chemical signal — dimethyl sulfide, or DMS — forms sulfur compounds in the atmosphere that promote cloud formation and help cool the planet. Seabirds consume the grazers, and fertilize the phytoplankton with iron, which is scarce in the vast Southern Ocean. The work was published March 3 in the Proceedings of the National Academy of Sciences.”The data are really striking,” said Gabrielle Nevitt, professor of neurobiology, physiology and behavior at UC Davis and co-author on the paper with graduate student Matthew Savoca. This suggests that marine top predators are important in climate regulation, although they are mostly left out of climate models, Nevitt said.”In addition to studying how these marine top predators are responding to climate change, our data suggest that more attention should be focused on how ecological systems, themselves, impact climate. Studying DMS as a signal molecule makes the connection,” she said.Nevitt has studied the sense of smell in ocean-going birds for about 25 years, and was the first to demonstrate that marine top predators use climate-regulating chemicals for foraging and navigation over the featureless ocean. DMS is now known to be an important signal for petrels and albatrosses, and the idea has been extended to various species of penguins, seals, sharks, sea turtles, coral reef fishes and possibly baleen whales, she said.Phytoplankton are the plants of the open ocean, absorbing carbon dioxide and sunlight to grow. When these plankton die, they release an enzyme that generates DMS.A role for DMS in regulating climate was proposed by Robert Charlson, James Lovelock, Meinrat Andreae and Stephen Warren in the 1980s. According to the CLAW hypothesis, warming oceans lead to more growth of green phytoplankton, which in turn release a precursor to DMS when they die. Rising levels of DMS in the atmosphere cause cloud formation, and clouds reflect sunlight, helping to cool the planet. …

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Pathways that direct immune system to turn ‘on’ or ‘off’ found

A key discovery explaining how components of the immune system determine whether to activate or to suppress the immune system, made by Kelvin Lee, MD, Professor of Oncology and Co-Leader of the Tumor Immunology and Immunotherapy Program at Roswell Park Cancer Institute (RPCI), and colleagues led to published findings being selected as the “Paper of the Week” by the Journal of Biological Chemistry (JBC). The honor places his work among the top 2 percent — in terms of significance and overall importance — of the year’s manuscripts reviewed by the journal.This research focused on the immune system’s dendritic cells (DCs), crucial cells that initiate and regulate immune responses. For example, the dendritic cells activate T lymphocytes to fight an infection or cancer. Curiously, they are also known to suppress the immune response. Determining when DCs turn the immune response “on” or “off” is a major question in immunology.For this project, Dr. Lee’s team explored two receptors (called CD80 and CD86) expressed on the surface of dendritic cells that trigger the cells to make either immune-stimulating factors (interleukin-6) or immune-suppressive factors (indolemine 2, 3 dioxygenase, IDO). They defined the intracellular pathways by which the receptors triggered each response and also uncovered a previously unrecognized interaction with another receptor called Notch-1.Understanding how these pathways are put together opens the door to targeting components of the pathway so physicians can manipulate the dendritic cells to either activate or suppress the immune system in a way that’s therapeutically beneficial.“Activating the immune response would enhance a patient’s response to a vaccine designed to prevent a cancer from growing or recurring,” explains Dr. Lee. “Suppressing or blocking an unwanted immune response would be helpful in organ-transplant cases, to prevent rejection, or in autoimmune diseases like lupus and rheumatoid arthritis.”With regard to cancer, Dr. Lee explains how manipulating the CD80/CD86 pathway could impact treatment for multiple myeloma, a cancer of a type of white blood cell in the bone marrow.“Myeloma cells use this pathway to survive and grow by inducing the DC to make IL-6 — which promotes the cancer cells’ survival — and IDO, which blocks anti-cancer responses,” he says. …

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A battery that ‘breathes’ could power next-gen electric vehicles

Sales of electric vehicles (EVs) nearly doubled in 2013, but most won’t take you farther than 100 miles on one charge. To boost their range toward a tantalizing 300 miles or more, researchers are reporting new progress on a “breathing” battery that has the potential to one day replace the lithium-ion technology of today’s EVs. They presented their work at the 247th National Meeting & Exposition of the American Chemical Society (ACS) in Dallas this week.”Lithium-air batteries are lightweight and deliver a large amount of electric energy,” said Nobuyuki Imanishi, Ph.D. “Many people expect them to one day be used in electric vehicles.”The main difference between lithium-ion and lithium-air batteries is that the latter replaces the traditional cathode — a key battery component involved in the flow of electric current — with air. That makes the rechargeable metal-air battery lighter with the potential to pack in more energy than its commercial counterpart.While lithium-air batteries have been touted as an exciting technology to watch, they still have some kinks that need to be worked out. Researchers are forging ahead on multiple fronts to get the batteries in top form before they debut under the hood.One of the main components researchers are working on is the batteries’ electrolytes, materials that conduct electricity between the electrodes. There are currently four electrolyte designs, one of which involves water. The advantage of this “aqueous” design over the others is that it protects the lithium from interacting with gases in the atmosphere and enables fast reactions at the air electrode. The downside is that water in direct contact with lithium can damage it.Seeing the potential of the aqueous version of the lithium-air battery, Imanishi’s team at Mie University in Japan tackled this issue. Adding a protective material to the lithium metal is one approach, but this typically decreases the battery power. …

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Climate change: Improving heat tolerance in trees

Is it possible to improve tolerance of trees to high temperatures and other types of stress derived of climate change? A research group of the Universidad Politcnica de Madrid (UPM), led by Luis Gmez, a professor of the Forestry School and the Centre for Plant Biotechnology and Genomics (CBGP), is studying the tolerance of trees using molecular and biotechnological tools. The research work was published in the last issue of the journal Plant Physiology.The obtained poplars in this project, with the collaboration of the Universidad de Mlaga, are significantly more tolerant to high temperatures than the control trees. These trees are also more tolerant to drought, to the presence of weed-killer, to in vitro and ex vitro crops, to contamination and other ways of abiotic stress that have an applied interest for forestry. This work is a continuation of a project started by of a research team of the UPM a decade ago. This study focuses on mechanisms that plant cells use to protect themselves from stress factors.Due to the human pressure on forests, the Food and Agriculture Organization of the United Nations (FAO) is promoting intensive plantations as an alternative to meet the global demand of wood and other products. Besides, plantations have social and economic benefits (job creation, wealth and rural development). This model change has significant ecological consequences.The role of forests is essential for climate change mitigation and biodiversity preservation, amongst others. A documentary “El Bosque Protector,” co-produced by the UPM and available on “A la Carta” of RTVE shows the result of this study. Tree farming plantations as a realistic alternative will be possible if the current yield significantly increases. …

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For older drivers one drink may be one too many, study finds

You may have only had one glass of wine with dinner, but if you’re 55 or older, that single serving may hit you hard enough to make you a dangerous driver. So, baby boomers, what you suspected is true: you can’t party like you used to.Sara Jo Nixon, a professor in the departments of psychiatry and psychology at the University of Florida and doctoral candidate Alfredo Sklar tested how drinking legally non-intoxicating levels of alcohol affect the driving skills of two age groups: 36 people ages 25 to 35 and 36 people ages 55 to 70. They found that although neither age group imbibed enough alcohol to put them over the legal driving limit, a blood alcohol level of 0.08, just one drink can affect the driving abilities of older drivers.Based on the study findings published in the journal Psychopharmacology in February, the researchers say it could be time to reassess legal blood alcohol levels for all drivers.”These simulations have been used a lot in looking at older adults, and they have been used at looking how alcohol affects the driving of younger adults, but no one’s ever looked at the combination of aging drivers and alcohol,” Sklar said.The study is the latest in a body of work by Nixon and her team that looks at how even moderate doses of alcohol affect aging adults.At the beginning of the study, both groups completed a driving task completely sober. The task took the drivers down a simulated winding 3-mile stretch of country road. The drivers stared straight ahead at a large computer monitor. Two computer monitors flanked the first, mimicking the side windows of a car and what the drivers would see in their peripheral vision. A stereo system played driving sounds. A console included a steering wheel and brake and gas pedals. Occasionally, the drivers would encounter an oncoming car, but they did not encounter other distractions.”There wasn’t even a cow,” said Nixon, who also is co-vice chair and chief of the division of addiction research in the department of psychiatry in the UF College of Medicine and UF’s Evelyn F. and William L. …

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Big stride in understanding PP1, the ubiquitous enzyme

In the Proceedings of the National Academy of Sciences, a team of scientists at Brown University reports a major step forward in determining the specific behavior of the ubiquitous enzyme PP1 implicated in a wide range of diseases including cancer.PP1, whose role is to enable the passage of molecular messages among cells, is found pretty much everywhere in the body. Its wide range of responsibilities means it is essential to many healthy functions and, when things go wrong, to diseases. But its very versatility has prevented it from being a target for drug development, said Rebecca Page, associate professor of biology at Brown and the paper’s corresponding author.”The amazing thing about PP1 is that no one has wanted to touch it for the most part as a drug target because PP1 is involved in nearly every biological process,” Page said. “It’s not like you could just target the PP1 active site for, let’s say, diabetes because then you are going to affect drug addiction, Alzheimer’s disease and all these other diseases at the same time.”In other words, make a medicine to block PP1 in one bodily context and you’d ruin it in all other contexts. Structural biologists such as Page and Brown co-author Wolfgang Peti have therefore been eager to learn what makes PP1 behave in specific ways in specific situations.The key is the way PP1 binds with more than 200 different regulatory proteins. Scientists know of these proteins and know the sequences of amino acids that compose them, but they don’t know their structure or how they actually guide PP1.”The ability to predict how these PP1 interacting proteins bind PP1 from sequence alone is still missing,” Page and her colleagues wrote in PNAS.Now, through experiments in which her team including lead author Meng Choy combined NMR spectroscopy, X-ray crystallography and techniques in biochemistry, she has learned how PP1 binds to a targeting protein called PNUTS, forming “binding motifs.” That knowledge, combined with what she learned in earlier studies about two other targeting proteins — NIPP1 and spinophilin — has allowed her team to predict how PP1 binds with 43 of the 200 regulatory proteins that give it specific behavior.”What this work in conjunction with two of our previous structures allowed us to do was to define two entirely new motifs,” she said. “From that, comparing the sequences with the known proteins that interact with PP1 whose structures we don’t have, we were able to predict that 20 percent of them likely interact in a way that is similar to these three proteins.”So by resolving the structure of just three proteins with PP1, Page now has the means to understand the binding of many proteins without having to resolve their structure. Instead she need only know the few motifs and the proteins’ sequences.As for PP1’s interactions with the other 80 percent or so of regulatory proteins, those remain a mystery. But Page said the success her team has had in the lab working with PP1 and resolving key motifs makes her optimistic that those interactions can be solved, too.Story Source:The above story is based on materials provided by Brown University. Note: Materials may be edited for content and length.

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Can an app help make life easier for children with ADHD?

We have tended to associate welfare technology with support for the elderly. Now researchers are looking at whether technology such as digital calendars and smartwatches can also provide support for children with autism and ADHD.Being able to function well in the morning is a challenge for parents of children with cognitive problems. Small details such as putting their leggings on inside out, or an adult saying something ‘the wrong way’ can trigger a temper tantrum and ruin the entire day. Children can become unruly, and some even become aggressive when something prevents them from following their routines and habits.This is one of many insights that researchers from SINTEF have learned from interviews with mothers of children who have autism or ADHD. “Being able to function well on a day-to-day basis is a big problem for these children — and for their families,” say Lisbet Grut and ystein Dale of SINTEF.Technology that can helpPrevious studies have shown that ordinary aids such as mobile phones and MP3 players can help young people with Asberger’s and autism to plan time and activities. Smartwatches may be able to help remind sufferers about appointments and tasks, and various software on smartphones and tablets can help them visualise sequences and structures in activities. The researchers believe that by developing aids such as this, they could help provide support in everyday situations. Now they want to test out their theories.Find solutions and allocate responsibilityA survey has already been carried out, in which researchers interviewed staff from NAV, Centres for Assistive Technology, service providers to the municipalities, assistive technology suppliers and selected families.Lisbet Grut explains that the aim has been to find out where the problems lie, and what the essential factors are in finding a solution. “ADHD is a group that is easily neglected, and it is difficult to help sufferers, because their problems are varied and complex,” she says. “But we believe that the work we are doing now will help us to find some good solutions, and provide clearer distinctions between the roles and responsibilities of the various support service organisations.”Service mechanism for rule-governed behaviour?The interviews with the mothers and the support services revealed that assistive technology tends to be provided more on the basis of a diagnosis than on functional problems and needs. …

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Competition breeds new fish species, study finds

Competition may play an important role during the evolution of new species, but empirical evidence for this is scarce, despite being implicit in Charles Darwin’s work and support from theoretical studies.Dr Martin Genner from Bristol’s School of Biological Sciences and colleagues used population genetics and experimental evidence to demonstrate a role for competition that leads to the differentiation of new species within the highly diverse cichlid fishes of Lake Tanganyika in East Africa.They found that the cichlid fish Telmatochromis temporalis shows two genetically distinct ecomorphs (local varieties of a species whose appearance is determined by its ecological environment), that strongly differ in body size and the habitat in which they live.Dr Genner said: “We found large-sized individuals living along the rocky shoreline of Lake Tanganyika and, in the vicinity of these shores, we found small-sized individuals, roughly half the size of the large ones, that live and breed in accumulations of empty snail shells found on sand.”According to the study, the bigger fish outcompete the smaller ones, driving them away from the preferred rocky habitats and into the neighbouring sand, where the smaller fish find shelter for themselves and their eggs in empty snail shells.”In effect, big and small fish use different habitats; and because of this habitat segregation, fish usually mate with individuals of similar size. There is virtually no genetic exchange between the large- and small-bodied ectomorphs,” Dr Genner commented.Speciation occurs when genetic differences between groups of individuals accumulate over time. In the case of Telmatochromis there are no obvious obstacles to the movement and interaction of individuals. But, the non-random mating between large- and small-bodied fish sets the stage for the evolutionary play.Dr Genner said: “The relevance of our work is that it provides experimental evidence that competition for space drives differential mating in cichlid fish and, in time, leads to the formation of new species. Nature has its ways — from body size differences to the formation of new species. And clearly, size does matters for Telmatochromis and for fish diversity.”Story Source:The above story is based on materials provided by University of Bristol. Note: Materials may be edited for content and length.

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Why dark chocolate is good for your heart

It might seem too good to be true, but dark chocolate is good for you and scientists now know why. Dark chocolate helps restore flexibility to arteries while also preventing white blood cells from sticking to the walls of blood vessels. Both arterial stiffness and white blood cell adhesion are known factors that play a significant role in atherosclerosis. What’s more, the scientists also found that increasing the flavanol content of dark chocolate did not change this effect. This discovery was published in the March 2014 issue of The FASEB Journal.”We provide a more complete picture of the impact of chocolate consumption in vascular health and show that increasing flavanol content has no added beneficial effect on vascular health,” said Diederik Esser, Ph.D., a researcher involved in the work from the Top Institute Food and Nutrition and Wageningen University, Division of Human Nutrition in Wageningen, The Netherlands. “However, this increased flavanol content clearly affected taste and thereby the motivation to eat these chocolates. So the dark side of chocolate is a healthy one.”To make this discovery, Esser and colleagues analyzed 44 middle-aged overweight men over two periods of four weeks as they consumed 70 grams of chocolate per day. Study participants received either specially produced dark chocolate with high flavanol content or chocolate that was regularly produced. Both chocolates had a similar cocoa mass content. Before and after both intervention periods, researchers performed a variety of measurements that are important indicators of vascular health. …

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Could PTSD involve immune cell response to stress? Study in mice raises question

Chronic stress that produces inflammation and anxiety in mice appears to prime their immune systems for a prolonged fight, causing the animals to have an excessive reaction to a single acute stressor weeks later, new research suggests.After the mice recovered from the effects of chronic stress, a single stressful event 24 days later quickly returned them to a chronically stressed state in biological and behavioral terms. Mice that had not experienced the chronic stress were unaffected by the single acute stressor.The study further showed that immune cells called to action as a result of chronic stress ended up on standby in the animals’ spleens and were launched from that organ to respond to the later stressor.Mice without spleens did not experience the same reactivation with the second stressor, signifying the spleen’s role as a reservoir for primed immune cells to remain until they’re activated in response to another stressor.The excessive immune response and anxiety initiated by a brief stressor mimic symptoms of post-traumatic stress disorder.The Ohio State University scientists are cautious about extending their findings to humans. But they say their decade of work with this model of stress suggests that the immune system has a significant role in affecting behavior. And they are the first to study this re-establishment of anxiety in animals with a later acute stressor.“No one else has done a study of this length to see what happens to recovered animals if we subject them again to stress,” said Jonathan Godbout, a lead author of the study and associate professor of neuroscience at Ohio State. “That retriggering is a component of post-traumatic stress. The previously stressed mice are living a normal rodent life, and then this acute stress brings everything back. Animals that have never been exposed to stress before were unaffected by that one event – it didn’t change behavioral or physiological properties.”The research is published online in the journal Biological Psychiatry.These scientists previously determined that in mice with chronic stress, cells from the immune system were recruited to the brain and promoted symptoms of anxiety. The findings identified a subset of immune cells, called monocytes, that could be targeted by drugs for treatment of mood disorders – including, potentially, the recurrent anxiety initiated by stress that is a characteristic of PTSD.The research reveals new ways of thinking about the cellular mechanisms behind the effects of stress, identifying two-way communication from the central nervous system to the periphery – the rest of the body – and back to the central nervous system that ultimately influences behavior.“We haven’t proffered that there is a cellular component to PTSD, but there very well might be. And it’s very possible that it sits in the periphery as we’ve been describing in the mouse,” said John Sheridan, senior author of the study, professor of oral biology and associate director of Ohio State’s Institute for Behavioral Medicine Research.In this model of stress, male mice living together are given time to establish a hierarchy, and then an aggressive male is added to the group for two hours at a time. The resident mice are repeatedly defeated, and this social defeat over six days leads to an inflammatory immune response and anxiety-like behavior.This kind of stress triggers the sympathetic nervous system and a commonly known fight-or-flight response. …

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It’s alive! Bacteria-filled liquid crystals could improve biosensing

Plop living, swimming bacteria into a novel water-based, nontoxic liquid crystal and a new physics takes over. The dynamic interaction of the bacteria with the liquid crystal creates a novel form of soft matter: living liquid crystal.The new type of active material, which holds promise for improving the early detection of diseases, was developed by a research collaboration based at Ohio’s Kent State University and Illinois’ Argonne National Laboratory. The team will present their work at the 58th annual Biophysical Society Meeting, held in San Francisco, Feb.15-19.As a biomechanical hybrid, living liquid crystal moves and reshapes itself in response to external stimuli. It also stores energy just as living organisms do to drive its internal motion. And it possesses highly desirable optical properties. In a living liquid crystal system, with the aid of a simple polarizing microscope, you can see with unusual clarity the wake-like trail stimulated by the rotation of bacterial flagella just 24-nanometers thick, about 1/4000th the thickness of an average human hair.You can also control and guide active movements of the bacteria by manipulating variables such as oxygen availability, temperature or surface alignment, thus introducing a new design concept for creating microfluidic biological sensors. Living liquid crystal provides a medium to amplify tiny reactions that occur at the micro- and nano-scales — where molecules and viruses interact — and to also easily optically detect and analyze these reactions. That suits living liquid crystal to making sensing devices that monitor biological processes such as cancer growth, or infection. Such microfluidic technology is of increasing importance to biomedical sensing as a means of detecting disease in its earliest stages when it is most treatable, and most cost-effectively managed.”As far as we know, these things have never been done systematically as we did before in experimental physics,” explained Shuang Zhou, a Ph.D. candidate at Ohio’s Kent State University. …

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Elevated brain aluminium, early onset Alzheimer’s disease in an individual occupationally exposed to aluminium

Research at Keele University in Staffordshire, UK, has shown for the first time that an individual who was exposed to aluminum at work and died of Alzheimer’s disease had high levels of aluminum in the brain.While aluminum is a known neurotoxin and occupational exposure to aluminum has been implicated in neurological disease, including Alzheimer’s disease, this finding is believed to be the first record of a direct link between Alzheimer’s disease and elevated brain aluminum following occupational exposure to the metal.In 2003 a 58-year-old Caucasian male with no previous medical history of note was diagnosed with Alzheimer’s disease. Ten years previous to this the man, from the north-east of England, began to work with the preparation of a novel material (DARMATT KM1) used as insulation in the nuclear fuel and space industries. This work exposed him to aluminum sulphate ‘dust’ on a daily basis over 8 years. An ‘ordinary’ dust mask was supplied to protect against inhalation of the materials. Within a short time of starting this work the man complained of headaches, tiredness and mouth ulcers. By 1999 he started to show problems in relation to memory and suffered depression.Following his death, aged 66, in 2011, a neuropathological examination confirmed advance stage Alzheimer’s disease. There then followed the most comprehensive investigation ever of the aluminum content of the frontal lobe of a single individual with 49 different tissue samples being measured for aluminum.Professor Chris Exley, of The Birchall Centre, at Keele University, said: “The results showed unequivocally that the frontal lobe contained an average aluminum content which was at least four times higher than might be expected for an age-matched control brain.”The observation that air-borne aluminum dust was most likely responsible for the elevated levels of aluminum in the brain must then heavily implicate the nose and possibly the lungs as the main routes of entry of aluminum into the body and the brain.”Overall, these results suggest very strongly that occupational exposure to aluminum contributed significantly to the untimely death of this individual with Alzheimer’s disease.”Story Source:The above story is based on materials provided by Keele University. Note: Materials may be edited for content and length.

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Psychologist shows why talking to kids really matters

Fifty years of research has revealed the sad truth that the children of lower-income, less-educated parents typically enter school with poorer language skills than their more privileged counterparts. By some measures, 5-year-old children of lower socioeconomic status (SES) score two years behind on standardized language development tests by the time they enter school.In recent years, Anne Fernald, a psychology professor at Stanford University, has conducted experiments revealing that the language gap between rich and poor children emerges during infancy. Her work has shown that significant differences in both vocabulary and real-time language processing efficiency were already evident at age 18 months in English-learning infants from higher- and lower-SES families. By age 24 months, there was a six-month gap between SES groups in processing skills critical to language development.Fernald’s work has also identified one likely cause for this gap. Using special technology to make all-day recordings of low-SES Spanish-learning children in their home environments, Fernald and her colleagues found striking variability in how much parents talked to their children. Infants who heard more child-directed speech developed greater efficiency in language processing and learned new words more quickly. The results indicate that exposure to child-directed speech — as opposed to overheard speech — sharpens infants’ language processing skills, with cascading benefits for vocabulary learning.Fernald and colleagues are now running a parent-education intervention study with low-income Spanish-speaking mothers in East San Jose, California, funded by the W. K. Kellogg Foundation. This new program, called Habla conmigo! …

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The physics of curly hair

The heroes and villains in animated films tend to be on opposite ends of the moral spectrum. But they’re often similar in their hair, which is usually extremely rigid or — if it moves at all — is straight and swings to and fro. It’s rare to see an animated character with bouncy, curly hair, since computer animators don’t have a simple mathematical means for describing it.However, change may be coming soon to a theater near you: In a paper appearing in the Feb. 13 issue of Physical Review Letters, researchers at MIT and the Universit Pierre et Marie Curie in Paris provide the first detailed model for the 3-D shape of a strand of curly hair.This work could have applications in the computer animation film industry, but it also could be used by engineers to predict the curve that long steel pipes, tubing, and cable develop after being coiled around a spool for transport. In the field, these materials often act like a stubborn garden hose whose intrinsic curves make it behave in unpredictable ways. In engineering terminology, these items — and hair — are all examples of a slender, flexible rod.Co-authors on the paper are Pedro Reis, an assistant professor in MIT’s Department of Civil and Environmental Engineering and Department of Mechanical Engineering; Basile Audoly and Arnaud Lazarus, of the Universit Pierre et Marie Curie; and former MIT graduate student James Miller, who is now a research associate at Schlumberger-Doll Research. Miller worked on this project as part of his doctoral thesis research and is lead author of the paper.”Our work doesn’t deal with the collisions of all the hairs on a head, which is a very important effect for animators to control a hairstyle,” Reis says. “But it characterizes all the different degrees of curliness of a hair and describes mathematically how the properties of the curl change along the arc length of a hair.”When Reis set out to investigate the natural curvature in flexible rods, he wasn’t thinking of hair. But as he studied several small flexible, curved segments of tubing suspended from a structure in his lab, he realized they weren’t so different from strands of curly hair hanging on a head. That’s when he contacted Audoly, who had previously developed a theory to explain the 2-D shape of human hair.Using lab experimentation, computer simulation, and theory — “the perfect triangle of science,” Reis says — the team identified the main parameters for curly hair and simplified them into two dimensionless parameters for curvature (relating to the ratio of curvature and length) and weight (relating to the ratio of weight and stiffness). …

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Abolition of fixed retirement age called for by new UK report

A report led by a professor at the University of Southampton recommends the worldwide removal of the fixed or default retirement age (DRA). Professor Yehuda Baruch from the Southampton Management School, in collaboration with Dr Susan Sayce from the University of East Anglia and Professor Andros Gregoriou from the University of Hull, has found that, on a global scale, current pension systems are unsustainable.Professor Baruch comments: “We have a global problem with funding pensions, which assume people will retire around their mid-60s. Young people are tending to start work later and in-turn start paying tax and pension contributions later. Older people are living longer, often in to their 90s, creating, in some cases, up to 30 years of retirement to provide for with their cover. This creates a funding gap.”Our study advocates the abolition of the default retirement age worldwide by governments and private companies — allowing people to consider a range of options on how and when to stop work, as well as greater flexibility over their pension plans. This would help ease funding problems.”The UK abolished the default retirement age in 2011, although a small number of organizations can fix their own DRA if they can justify reasons for doing so. However, other countries still have fixed retirement ages. The report authors have used the UK as a case study to examine the benefits and pitfalls of a more flexible approach to retirement.The researchers conducted financial analysis based on Monte Carlo simulation methodology to interrogate pension and other financial data. Their results suggest that where DRA is in place the pensions system is not sustainable in the long-run and recommend ending its use in other countries, in line with the UK approach.Professor Baruch says: “We would like to see a situation where people globally can be much more in control of when they retire. For example, they may want to work into their 70s or even 80s, but perhaps want to change the type or volume of work they take on.”Our study suggests that old age can be seen as holding the prospect of long-term stable contributions to society, rather than a decline or preparation for giving up work altogether — which can lead to pressure on the public purse.”The researchers conclude that if the default retirement age is to be successfully abolished worldwide, there needs to be a shift in cultural attitudes towards older workers and the perception of their value and productivity — as well as a change in the labour market to help older workers step into jobs, as well as out of jobs. …

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Embrace the cold: Evidence that shivering and exercise may convert white fat to brown

A new study suggests that shivering and bouts of moderate exercise are equally capable of stimulating the conversion of energy-storing ‘white fat’ into energy-burning ‘brown fat’.Around 50 g of white fat stores more than 300 kilocalories of energy. The same amount of brown fat could burn up to 300 kilocalories a day.Endocrinologist Dr Paul Lee, from Sydney’s Garvan Institute of Medical Research, recently undertook the study at the National Institutes of Health (NIH) in Washington, funded as an NHMRC Early Career Research Fellow.His work uncovered a way that fat and muscle communicate with each other through specific hormones — turning white fat cells into brown fat cells to protect us against cold.Dr Lee showed that during cold exposure and exercise, levels of the hormone irisin (produced by muscle) and FGF21 (produced by brown fat) rose. Specifically, around 10-15 minutes of shivering resulted in equivalent rises in irisin as an hour of moderate exercise. In the laboratory, irisin and FGF21 turn human white fat cells into brown fat cells over a period of six days. The study is now published in Cell Metabolism.We are all born with supplies of brown fat around our necks, nature’s way of helping to keep us warm as infants. Until only a few years ago, it was thought to vanish in early infancy, but we now know that brown fat is present in most, if not all, adults. Adults with more brown fat are slimmer than those without.”Excitement in the brown fat field has risen significantly over last few years because its energy-burning nature makes it a potential therapeutic target against obesity and diabetes,” said Dr Lee.”White fat transformation into brown fat could protect animals against diabetes, obesity and fatty liver. Glucose levels are lower in humans with more brown fat.”In the current study, Lee set out to understand the mechanism underlying the activation of brown fat. It was already known that cold temperatures stimulate brown fat, but was unclear how the body signals that message to its cells.The body can sense and relay environmental changes to different organs via nerves and hormones. Being an endocrinologist, Lee investigated the hormones that are stimulated by cold environments.”When we are cold, we first activate our brown fat because it burns energy and releases heat to protect us. …

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