Culture

Philadelphia, February 11, 2019 - As marijuana legalization sweeps North America, use of the substance has been on the rise, and the public's attitude is shifting. An increasing number of people believe that "weed" is the safest recreational drug, one that carries health benefits that outweigh its risks. Those assumptions are challenged in an article and editorial published in the Canadian Journal of Cardiology that examine the story of a patient who developed crushing chest pain and myocardial ischemia after consuming most of a marijuana lollipop.

"Marijuana can be a useful tool for many patients, especially for pain and nausea relief. At the same time, like all other medications, it does carry risk and side effects. In a recent case, inappropriate dosing and oral consumption of marijuana by an older patient with stable cardiovascular disease resulted in distress that caused a cardiac event and subsequent reduced cardiac function," said Alexandra Saunders, MD, Dalhousie University, Internal Medicine Program and Horizon Health Network's Department of Cardiology, Saint John, NB, Canada.

The case report describes a 70-year-old man with stable coronary artery disease, taking the appropriate cardiac medications, who ate most of a lollipop that was infused with 90 mg of THC (delta-9-tetrahydrocannabinol) to relieve pain and aid sleep, which caused him to have a potentially-serious heart attack. He consumed a much larger dose than the 7 mg that is typically ingested by smoking a single joint or taking the 2.5 mg starting dose of dronabinol (Marinol), a synthetic THC marketed for nausea and appetite stimulation in AIDS and cancer patients. While the patient had smoked marijuana in his youth, he had not done so since the THC content of the substance had increased significantly from three percent to 12 percent. He was also not familiar with the time-delayed and extended effect of oral THC dosing.

The patient's cardiac event was likely triggered by unexpected strain on his body from anxiety and fearful hallucinations caused by the unusually large amount of THC he ingested. His sympathetic nervous system was stimulated, causing increased cardiac output with tachycardia, hypertension, and catecholamine (stress hormone) release. After the psychotropic effects of the drug wore off, and his hallucinations ended, his chest pain stopped.

A number of prior case reports, as well as epidemiological studies, have described the association between cannabis use and acute cardiovascular (CV) adverse events, including myocardial infarction, stroke, arrhythmias, and sudden death.

"Most previous research on marijuana-induced myocardial ischemia focused mostly on younger patients and did not focus on its different formulations and potencies. As a result of widespread marijuana legalization, healthcare providers need to understand and manage cannabis use and its complications in older patients, particularly in those with cardiovascular disease," said Robert S. Stevenson, MD, Horizon Health Network, Department of Cardiology, Saint John, NB, Canada.

CV toxicity of marijuana is described in an accompanying editorial. It can be viewed as a consequence of one or more the following: 1) inhalation of combustion products of marijuana; 2) direct CV effects of THC; and 3) indirect effects of THC related to acute anxiety, hallucination, and/or psychosis. Individuals who are THC-naïve and are not used to taking mind-altering drugs can become highly distressed by impaired cognition and feelings of loss of control produced by THC. Extreme emotional responses in the context of THC psychiatric toxicity are associated with surges of catecholamines, which can have adverse acute CV effects. Important considerations with respect to cannabis toxicity are the pattern of use, dose, route of administration, and degree of tolerance.

"The legalization of cannabis has considerable public support but also raises public health concerns," commented the editorial's author, Neal L. Benowitz, MD, Chief, Division of Clinical Pharmacology and Experimental Therapeutics, Medical Service, Departments of Medicine, and Biopharmaceutical Sciences; Center for Tobacco Control Research and Education, University of California, San Francisco, CA, USA. "Some users may benefit from the social and medical effects, but others will be at risk for adverse health outcomes. Little information has been disseminated to patients or healthcare providers about cannabis use in older patients, and in particular those with cardiovascular disease. For better or worse, providing advice and care to such patients who are using cannabis is now necessary for the provision of optimal medical care to these patients."

BOSTON - (February 11, 2019) - It's well-known that exercise improves health, but understanding how it makes you healthier on a molecular level is the question researchers at Joslin Diabetes Center are answering.

After performing experiments in both humans and mice, the researchers found that exercise training causes dramatic changes to fat. Additionally, they discovered that this "trained" fat releases factors into the bloodstream that can have positive effects on health. The study was published online February 11, 2019, in Nature Metabolism.

It's known that fat cells secrete proteins called adipokines, and that many adipokines increase with obesity, having harmful effects on metabolism and health.

"In contrast to the negative effects of many adipokines, our study identified transforming growth factor beta 2 (TGF-beta 2) as an adipokine released from adipose tissue (fat) in response to exercise that actually improves glucose tolerance," says Laurie J. Goodyear, PhD, Head of Joslin's Section on Integrative Physiology and Metabolism and study co-author.

Not only did exercise-stimulated TGF-beta 2 improve glucose tolerance, treating obese mice with TGF beta 2 lowered blood lipid levels and improved many other aspects of metabolism.

"The fact that a single protein has such important and dramatic effects was quite impressive," says Goodyear, Professor of Medicine at Harvard Medical School.

Two years ago, the international research team first demonstrated that adipose tissue offers beneficial metabolic effects in response to exercise.

"Our hypothesis was that exercise is changing the fat, and as a result of that change, the fat releases these beneficial proteins into the bloodstream," says Goodyear. "Before this discovery, we always just focused on the positive effects of muscle."

Building on this insight, Joslin researchers sought to identify the adipokines released from fat in exercise. To do so, they ran a series of molecular experiments in both humans and mice. They identified levels of adipokines in men before and after a cycle of exercise. They also studied exercising mice.

Their analysis identified TGF beta 2 as one of the proteins upregulated in exercise in humans and mice. Additional investigation confirmed that levels of this one adipokine actually increased in the fat tissue as well as in the bloodstream with exercise, in both cases.

To find out if the protein promoted beneficial metabolic effects, they treated the mice with TGF beta 2. The experiment showed a number of positive metabolic effects in the mice, including improved glucose tolerance and increased fatty acid uptake.

Next, they fed the mice a high fat diet, causing the animals to develop diabetes. To know if TGF beta 2 was actually responsible for the metabolic effects, they treated the diabetic mice with TGF beta 2. This reversed the negative metabolic effects of the high fat diet, similar to what happens with exercise.

"Our results are important because it's really the first demonstration of an exercise-released adipokine that can have beneficial metabolic effects on the body," says Goodyear.

Another significant finding was that lactic acid, which is released during exercise, serves as an integral part of the process. Lactate is released by the muscles during exercise then travels to the fat where it triggers the release of TGF beta 2.

"This research really revolutionizes the way we think about exercise, and the many metabolic effects of exercise. And, importantly, that fat is actually playing an important role in the way exercise works," says Goodyear.

These findings suggest that TGF beta 2 may be a potential therapy for treatment of high blood sugar, and eventually a potential therapy for type 2 diabetes. Long-term studies will be needed to determine the safety of TGF beta 2 treatment.

Light pollution affects the skies over most of the world's key wildlife areas, new research shows.

The study, by the University of Exeter and Birdlife International, focussed on "skyglow" - light scattered and reflected into the atmosphere that can extend to great distances.

Researchers found less than a third of the world's Key Biodiversity Areas (KBAs) have completely pristine night skies, and more than half lie entirely under artificially bright skies.

Night-time light has been shown to have wide-ranging effects on individual species and entire ecosystems.

"These results are troubling because we know many species can respond even to small changes in night-time light," said lead author Dr Jo Garrett, of the University of Exeter.

"Night-time lighting is known to affect microbes, plants and many groups of animals such crustaceans, insects, fish, amphibians, reptiles, birds and mammals.

"It has an enormous range of effects, including causing trees to produce leaves earlier in the season and birds to sing earlier in the day, changing the proportion of predators in animal communities, and changing the cycling of carbon in ecosystems. Some effects can occur at very low light levels."

KBAs are places identified by the KBA Partnership as being important for preserving global biodiversity, and the new study uses a recent atlas of skyglow to see how KBAs are affected.

"Pristine" skies were defined as those with artificial light no more than 1% above the natural level.

At 8% or more above natural conditions, light pollution extends from the horizon to the zenith (straight upwards) and the entire sky can be considered polluted.

The findings showed:

29.5% of KBAs had completely pristine night-time skies.

51.5% contained no area with pristine night skies.

21% were entirely under night skies polluted to the zenith.

51.9% of KBAs were completely free of skies polluted to the zenith

46% of KBAs in the Middle East were entirely under skies polluted to the zenith. The next-highest figures were Europe (34%) and the Caribbean (32%).

"Unsurprisingly, the likelihood of skyglow tends to increase in areas with higher GDP, and in areas with higher human population density," said senior author Professor Kevin Gaston.

"This suggests that the proportion of KBAs experiencing skyglow will increase in parallel with the development of economies.

"Skyglow could be reduced by limiting outdoor lighting to levels and places where it is needed, which would also result in considerable cost savings and lower energy use."

The paper, published in the journal Animal Conservation, is entitled: "Skyglow extends into the world's Key Biodiversity Areas."

Adding olefin enables efficient solvent-free cross-coupling reactions, leading to environmentally friendly syntheses of a wide range of organic materials.

A cross coupling reaction is typically performed in an organic solvent and leads to the production of a large amount of solvent waste, which is often harmful to the environment. A new strategy developed by Hokkaido University researchers in Japan opens the door for more environmentally friendly solvent-free solid-state cross coupling processes using mechanochemistry. It also has many potential applications, including the development of organic materials found in solar cells and light-emitting diodes.

Cross-coupling reactions proceed efficiently in the presence of a metal catalyst to form a wide range of organic molecules with novel properties. In particular, the Nobel-prize-winning palladium-catalysed cross-coupling reactions have long been used in the synthesis of natural products, in medicinal chemistry, and in polymer and materials science.

To reduce environmental waste, researchers have been looking at methods to enable efficient organic syntheses that use less or no solvent. In this context, "solid-state organic transformations" have received considerable research attention, but improving the efficiency of cross-coupling reactions in solid media remains a challenge.

In a study published in Nature Communications, Hokkaido University organic chemists Koji Kubota, Hajime Ito and their colleagues developed a new strategy for solid-state palladium-catalysed cross-coupling reactions using mechanochemistry that enables efficient solvent-free synthesis of organic materials.

Two solid organic materials were placed inside a ball milling jar that contains a stainless steel grinding ball. A palladium-based catalyst was also added. The jar undergoes a shaking process that causes the ball to grind the solid compounds, initiating a cross-coupling reaction.

They found that the palladium-based catalyst tended to aggregate during the reaction, which may lead to catalyst deactivation. But, when olefin such as 1,5-cyclooctadiene was added to the mixture, it acted as a dispersant for the palladium-based catalyst, facilitating a more efficient solid-state cross-coupling reaction. When olefin was added, the conversion rate of the reaction went up from less than 30% to 99%.

"Our protocol should be particularly useful for reducing the amount of organic solvent used in industry that is harmful to the environment. It will also make the production process less costly," said Hajime Ito. "The new method could be applied to, for example, the production of triarylamines that can be found in a wide range of organic materials including solar cells and light-emitting diodes."

Acrylics are an incredibly diverse and useful family of chemicals used in all kinds of products, from diapers to nail polish. Now, a team of researchers from UConn and ExxonMobil describe a new process for making them. The new method would increase energy efficiency and reduce toxic byproducts, they report in the Feb. 8 issue of Nature Communications.

The global market for acrylic acid is enormous. The world used close to 5 million metric tonnes of it in 2013, according to industry group PetroChemicals Europe. And no wonder, for acrylics and the closely related acrylates are the building blocks for many kinds of plastics, glues, textiles, dyes, paints, and papers. Strung together in long chains, they can make all kinds of useful materials. Acrylate mixed with sodium hydroxide, for example, makes a super absorbent material used in diapers. Add extra methyl groups (carbon plus three hydrogens), and acrylate makes plexiglass.

The current industrial processes for making acrylics require high temperatures close to 450 F, and produce unwanted and sometimes harmful byproducts, such as ethylene, carbon dioxide, and hydrogen cyanide.

UConn chemist Steve Suib, director of the University's Institute for Materials Science, and colleagues at UConn and ExxonMobil have designed a new way of making acrylics at mild temperatures. Their technique can be finely tuned to avoid producing unwanted chemicals.

"Scientists at ExxonMobil Research & Engineering partnering with professor Suib's group in UConn have been probing new technologies that can lower energy intensity, skip steps, improve energy efficiency, and reduce CO2 footprint in the production process of acrylics," says Partha Nandi, a chemist at ExxonMobil. "The recent publication in Nature Communications describes discovery of a new route to produce a class of acrylate derivatives in potentially fewer steps and with less energy."

The technique uses a porous catalyst made of manganese and oxygen. Catalysts are materials used to speed up reactions. Often, they provide a surface for the molecules to sit on while they react with each other, helping them to meet up in the right configurations to do the deed. In this case, the pores fill that role. The pores are 20 to 500 Angstroms wide, big enough for fairly large molecules to fit inside. The manganese atoms in the material can trade their electrons with nearby oxygens, which makes it easier for the right chemical reactions to happen. Depending on the starting ingredients, the catalyst can facilitate all different kinds of acrylics and acrylates, with very little waste, Suib says.

"We hope this can be scaled up," he says. "We want to maximize yield, minimize temperature, and make an even more active catalyst," that will help the reaction go faster. The group also found adding a little bit of lithium helped speed things up, too. They are currently studying the exact role of lithium, and experimenting with ways of improving the manganese and oxygen catalyst.

NEW YORK, NY (Feb. 8, 2019)--Athletes know a vigorous workout can release a flood of endorphins: "feel-good" hormones that boost mood. Now there's evidence that exercise produces another hormone that may improve memory and protect against Alzheimer's disease, according to a study co-led by Ottavio Arancio, MD, PhD, a researcher at Columbia University's Vagelos College of Physicians and Surgeons and Taub Institute for Research on Alzheimer's Disease and the Aging Brain.

The study was published in Nature Medicine.

Physical activity is known to improve memory, and studies suggest it may also reduce the risk of Alzheimer's disease. But researchers don't understand why.

A few years ago, exercise researchers discovered a hormone called irisin that is released into the circulation during physical activity. Initial studies suggested that irisin mainly played a role in energy metabolism. But newer research found that the hormone may also promote neuronal growth in the brain's hippocampus, a region critical for learning and memory.

"This raised the possibility that irisin may help explain why physical activity improves memory and seems to play a protective role in brain disorders such as Alzheimer's disease" says Arancio, who is a professor of pathology and cell biology and of medicine at Columbia University Vagelos College of Physicians and Surgeons.

Irisin is reduced in brains of people with Alzheimer's

In the new study, Arancio and his colleagues at the Federal University of Rio de Janeiro in Brazil and Queens University in Canada first looked for a link between irisin and Alzheimer's in people. Using tissue samples from brain banks, they found that irisin is present in the human hippocampus and that hippocampal levels of the hormone are reduced in individuals with Alzheimer's.

To explore what irisin does in the brain, the team turned to mice. These experiments show that irisin, in mice, protects the brain's synapses and the animals' memory: When irisin was disabled in the hippocampus of healthy mice, synapses and memory weakened. Similarly, boosting brain levels of irisin improved both measures of brain health.

Swimming boosts irisin, protects memory in mice

The researchers then looked at the effect of exercise on irisin and the brain. In the study's most compelling experiments, the researchers found that mice who swam nearly every day for five weeks did not develop memory impairment despite getting infusions of beta amyloid -- the neuron-clogging, memory-robbing protein implicated in Alzheimer's.

Blocking irisin with a drug completely eliminated the benefits of swimming, the researchers also found. Mice who swam and were treated with irisin-blocking substances performed no better on memory tests than sedentary animals after infusions with beta amyloid.

Together the findings suggest that irisin could be exploited to find a novel therapy for preventing or treating dementia in humans, Arancio says. His team is now searching for pharmaceutical compounds that can increase brain levels of the hormone or can mimic its action.

"In the meantime, I would certainly encourage everyone to exercise, to promote brain function and overall health," he said. "But that's not possible for many people, especially those with age-related conditions like heart disease, arthritis, or dementia. For those individuals, there's a particular need for drugs that can mimic the effects of irisin and protect synapses and prevent cognitive decline."

A Rutgers-led team has discovered two genes that make some strains of harmful Staphyloccocus bacteria resistant to treatment by copper, a potent and frequently used antibacterial agent.

The discovery shows that Staphyloccocus aureus can acquire additional genes that promote infections and antibacterial resistance and may open new paths for the development of antibacterial drugs, according to a study in the Journal of Biological Chemistry.

Researchers at Rutgers University-New Brunswick found the two genes in some strains of S. aureus bacteria. The genes protect the germs from copper, which is increasingly used in the global fight against severe infections.

The Staphylococcus aureus bacterium - a leading cause of serious and life-threatening infections in the United States - is highly resistant to antibiotics. Some strains of S. aureus have newly acquired genes embedded in their genome in pieces of DNA called transposons. DNA can be transferred from one organism to another, and transposons help the acquired DNA rapidly become a permanent part of the recipient's chromosome.

Transposons aid in the spread of genes that can give rise to bacteria that are resistant to antibiotics and more likely to cause disease. The newly discovered genes are encoded within a transposon.

This process likely contributed to the recent North American epidemic of staph infections, according to Jeffrey M. Boyd, study senior author and associate professor in the Department of Biochemistry and Microbiology in Rutgers' School of Environmental and Biological Sciences.

Copper has been used for thousands of years to sterilize wounds and drinking water, and hospitals recently began using it against bacteria found on medical instruments and other surfaces. But the two newly discovered genes, named copB and copL, encode proteins that help remove copper from S. aureus cells and prevent it from entering.

The genes may promote the survival of S. aureus in settings, such as in hospitals, that could lead to infections - and/or they may lead to S. aureus strains with higher copper resistance.

S. aureus bacteria live on skin. They are a leading cause of serious and life-threatening infections partly because many strains of S. aureus, such as MRSA and VRSA, are highly resistant to antibiotics.

Rutgers scientists, in collaboration with scientists at the University at Buffalo, also revealed the 3D structure of the copL protein in the B. subtilis bacterium, a relative of S. aureus, using nuclear magnetic resonance (NMR) methods. Those methods were also used to identify the area where copper binds to the surface of the protein.

"This structure provides the basis for rational drug design and could lead to a novel path for antibacterial drug discovery," said co-author Gaetano T. Montelione, Jerome and Lorraine Aresty Chair and a Distinguished Professor in the Department of Molecular Biology and Biochemistry in the School of Arts and Sciences. He is also affiliated with the Center for Advanced Biotechnology and Medicine.

Using data from Bristol's Children of the 90s study the research is one of a series from the University of Bristol, that examines a parental personality attribute known as the 'locus of control'. This is a psychological measure of how much someone believes that they have control over the outcome of events in their life or whether external forces beyond their control dictates how life turns out.

Those with an external locus of control would believe there is little point in making an effort as what happens to them is due to luck and circumstances, in contrast with internally controlled people who are motivated into action because they feel they can influence what is going to happen.

Researchers examined the 'locus of control' by using responses from questionnaires completed by over 1600 pregnant women who took part in the Children of the 90s study. They then looked at the mathematical and scientific reasoning and problem-solving skills of their offspring at the ages of 8, 11 and 13 assessed in school using specially designed tests. This study is among the first to link the prenatal locus of control of parents to the maths and science abilities of their offspring years later.

Findings reveal that mothers with an internal locus of control before their child was born (those who believe in the connection between their actions and what happens to them) were more likely to have a child who is good at maths and science. Compared to their externally controlled peers, internally focussed mothers also were more likely to provide their children with diets that assist brain development, to more frequently read stories to them and to show an interest in their child's homework and academic progress.

Lead author and founder of the Children of the 90s study Professor Jean Golding OBE said:

"It is widely known that the locus of control of a child is strongly associated with their academic achievements but until now we didn't know if mothers' locus of control orientation during pregnancy had a role to play in early childhood. Thanks to the longitudinal data from Children of the 90s study we can now make these associations.

"If our findings, that mothers' attitudes and behaviours can have an effect on their child's academic abilities, can be replicated it would suggest that more efforts should be made to increase the opportunities for mothers to feel that their behaviours will have a positive outcome for themselves and their children. It would help future generations raise healthy, confident and independent children.

"The next steps for this area of psychology will be for researchers to look at this at an international level to see if the findings are replicated. Other factors that will be important will be to undertake an intervention study to assess whether encouraging women to become more internal will improve the academic development of their children."

Candler Professor of Psychology Stephen Nowicki at Emory University, Atlanta, a co-author, and expert on locus of control added:

"Internal parents believe that they have behavioural choices in life. This and other findings from our child development work with the University of Bristol with expectant parents show that when they expect life outcomes to be linked to what they do their children eat better, sleep better and are better able to control their emotions. Such children later in childhood are also more likely to have greater academic achievements, fewer school related personal and social difficulties and less likelihood of being obese.

"It is possible for a parent to change their outlook; we've demonstrated in the past that parents who become more internal (i.e. learn to see the connections between what they do and what happens to their children) improved their parenting skills which would have a positive effect on their children's personal, social and academic lives."

Barcelona, 8 February 2019- In recent decades, Europe has experienced a downward trend in the annual number of deaths. Not only was this trend not arrested by the economic recession that started in 2008, in fact, the rate of decline increased during the recession years. This acceleration has been evidenced by the results of a study published in Nature Communications and led by the Barcelona Institute for Global Health (ISGlobal), a centre supported by "la Caixa".

The objective of the study was to ascertain whether the pattern of mortality in Europe was procyclical or countercyclical, that is, whether the downward trend in the death rate accelerates or slows down during periods of economic recession. The researchers analysed data on daily mortality and variations in per capita gross domestic product (GDP) across 140 regions in 15 European countries for the period 2000-2010.

Statistical analysis of the dataset not only showed an acceleration in the decline in mortality during the recession years, but also revealed that the tendency towards a reduction in mortality was more marked in the countries and regions where the recession was most severe.

The authors cite several factors to explain this correlation between economic recession and a faster decline in mortality. In the opinion of Joan Ballester, ISGlobal researcher and first author of the study, "Periods of macroeconomic recession are associated with lower levels of pollution and fewer accidents in the workplace and on the roads. These are the factors most likely to have the greatest influence on accelerating the decline in mortality. Alcohol and tobacco consumption also fall during periods of greater austerity, as do the prevalences of sedentary lifestyles and obesity. While the underlying mechanisms are still not well established, the findings of some studies also point to the influence of other factors, such as work stress and the fact that healthy habits demand time, something less available to a person working in a full-time job."

The study found considerable variations across Europe. For example, in Spain, where the mortality rate was declining at a rate of 2% per year before the economic crisis, the impact of the recession was marked and mortality started to decline at a rate of 3% annually. In Germany, by contrast, where the recession was short and less severe, the annual decline in mortality went from 2.4% annually to 0.7%. "Of course, recessions are not a desirable way to boost life expectancy" Joan Ballester adds, "What we need to ensure is that periods of economic expansion are also characterised by better air quality, fewer accidents and more healthy lifestyles".

The study also took into account the daily temperatures recorded during the whole study period to determine whether the trends observed were affected by the seasons. "The statistical analysis revealed that the relationship between variations in GDP and mortality was accentuated during the coldest months of the year, an indication that the causes of death may to some degree be dependent on the season", explains Xavier Rodó, head of ISGlobal's Climate and Health Programme and ICREA professor.

Physicists from the University of Basel have developed a new method to examine the elasticity and binding properties of DNA molecules on a surface at extremely low temperatures. With a combination of cryo-force spectroscopy and computer simulations, they were able to show that DNA molecules behave like a chain of small coil springs. The researchers reported their findings in Nature Communications.

DNA is not only a popular research topic because it contains the blueprint for life - it can also be used to produce tiny components for technical applications. In a process known as DNA origami, scientists can manipulate the genetic material in such a way that folding the DNA strands creates tiny two- and three-dimensional structures. These can be used, for example, as containers for pharmaceutical substances, as conductive tubes and as highly sensitive sensors.

Measurement at low temperatures

To be able to form the desired shapes, it is important to be familiar with the structure, the elasticity and the binding forces of the DNA components being used. These physical parameters cannot be measured at room temperature, because the molecules are constantly in motion.

The same is not true at low temperatures: the team led by Professor Ernst Meyer from the Swiss Nanoscience Institute and the University of Basel's Department of Physics have now used cryo-force microscopy for the first time to characterize DNA molecules and examine their binding forces and elasticity.

Detached piece by piece

The scientists placed only few nanometer long DNA strands containing 20-cytosine nucleotides on a gold surface. At a temperature of 5 Kelvin, one end of the DNA strand was then pulled upwards using the tip of an atomic force microscope. In the process, the individual components of the strand freed themselves from the surface little by little. This enabled the physicists to record their elasticity as well as the forces required to detach the DNA molecules from the gold surface.

"The longer the detached piece of DNA, the softer and more elastic the DNA segment becomes," explains lead author Dr. Rémy Pawlak. This is because the individual components of the DNA behave like a chain of multiple coil springs connected to one another. Thanks to the measurements, the researchers were able to determine the spring constant for the individual DNA components.

Computer simulations clarify that the DNA is detached discontinuously from the surface. This is due to the breaking up of bonds between the cytosine bases and the DNA backbone from the gold surface, and their abrupt movements over the gold surface. The theoretical elasticity values correlate very closely with the experiments and confirm the model of serially arranged springs.

Snapshots provide insight

The studies confirm that cryo-force spectroscopy is very well suited to examining the forces, elasticity and binding properties of DNA strands on surfaces at low temperatures.

"As with cryogenic electron microscopy, we take a snapshot with cryo-force spectroscopy, which gives us an insight into the properties of DNA," explains Meyer. "In future, we could also make use of scanning probe microscope images to determine nucleotide sequences."

Under climate change, plants and animals will shift their habitats to track the conditions they are adapted for. As they do, the lands surrounding rivers and streams offer natural migration routes that will take on a new importance as temperatures rise.

An open-access study led by the University of Washington pinpoints which riverside routes in Washington, Oregon, Idaho and western Montana will be the most important for animals trying to navigate a changing climate. The study was published this fall in PLOS ONE.

"This corridor network is already there, and it's already important for animal movement," said lead author Meade Krosby, a scientist in the UW's Climate Impacts Group. "Under climate change these will become 'superhighways' for animals that are seeking new places to live. We've identified ones that could be priorities for conservation and restoration."

Riparian areas -- areas of habitat along the banks of rivers and streams -- are known to be used by bears, coyotes, wolves, deer, mountain lions and other large mammals. But these regions could also benefit smaller mammals, like beavers and marmots, and even insects, birds and other species looking for cooler, moister terrain as conditions become less habitable.

"We aren't the first to realize that riparian areas are likely to be really important for animals seeking refuge from warmer or drier conditions, or for connecting fragmented habitats under climate change," Krosby said. "But we hadn't seen anybody identify which riparian areas would be particularly valuable in the future."

The authors developed a ranking system for riparian areas and applied it to the Northwest, creating a general technique that could be applied elsewhere. They rated the land surrounding rivers and streams for various features that would help animals on the move: width; amount of shade; tree cover; connection across temperature gradients; and general condition of the landscape.

Results show that the highest-quality routes in the Northwest are mostly in the mountains, which have shaded, well-protected riparian corridors that connect warmer to cooler habitats.

The authors then looked at which areas should be priorities for restoration -- places that are not currently protected, or that offer the only natural pathway linking warmer and cooler landscapes. Here the routes through the Columbia Plateau, covering Eastern Washington, central Oregon and western Idaho, popped out as particularly important.

"If you look at an aerial photograph of an agricultural or urban landscape you'll see these green corridors that follow streams and rivers," Krosby said. "Humans use the flat areas of the landscape: we live there, we farm there, we use it for all kinds of things. So the riparian areas in these landscapes may not be in the best shape, but in some ways they're the most valuable, because they're the only natural habitat left."

The authors don't identify individual waterways as priorities for riparian conservation. Instead they leave it to regional managers to single out individual areas and choose methods -- whether it be working with landowners to keep areas in a natural state, planting native vegetation, removing invasive species along streams, creating easements in property deeds, or other methods - to ensure that riverside land remains friendly to wildlife movement.

"Riparian areas offer a huge bang-for-buck as conservation opportunities in the effort to reconnect our fragmented habitats," Krosby said. "The nice thing about riparian conservation is it's a two-fer: The same vegetation that provides cover for terrestrial species moving through riparian zones can, for example, help shade streams to cool water temperatures for aquatic species."

The study is part of a growing trend in wildlife conservation. This winter, the state of Washington anticipates opening a wildlife overpass over Interstate 90 at Snoqualmie Pass, which will allow animals to safely cross the freeway. That infrastructure in combination with other measures could help animal populations be more resilient to climate change.

"The idea is to have a whole network: You want to make sure that your landscape is permeable to wildlife movement," Krosby said. "That's important now, and it's especially important under climate change, because moving to track shifting habitats is the primary way that species deal with a changing climate."

Human tissues experience a variety of mechanical stimuli that can affect their ability to carry out their physiological functions, such as protecting organs from injury. The controlled application of such stimuli to living tissues in vivo and in vitro has now proven instrumental to studying the conditions that lead to disease.

At EPFL, Selman Sakar's research team has developed micromachines able to mechanically stimulate cells and microtissue. These tools, which are powered by cell-sized artificial muscles, can carry out complicated manipulation tasks under physiological conditions on a microscopic scale.

The tools consist of microactuators and soft robotic devices that are wirelessly activated by laser beams. They can also incorporate microfluidic chips, which means they can be used to perform combinatorial tests that involve high-throughput chemical and mechanical stimulation of a variety of biological samples. This research has been published in Lab on a Chip.

Like Legos

The scientists came up with the idea after observing the locomotor system in action. "We wanted to create a modular system powered by the contraction of distributed actuators and the deformation of compliant mechanisms," says Sakar.

Their system involves assembling various hydrogel components - as if they were Lego bricks - to form a compliant skeleton, and then creating tendon-like polymer connections between the skeleton and the microactuators. By combining the bricks and actuators in different ways, scientists can create an array of complicated micromachines.

"Our soft actuators contract rapidly and efficiently when activated by near-infrared light. When the entire nanoscale actuator network contracts, it tugs on the surrounding device components and powers the machinery," says Berna Ozkale, the study's lead author.

With this method, scientists are able to remotely activate multiple microactuators at specified locations - a dexterous approach that produces exceptional results. The microactuators complete each contraction-relaxation cycle in milliseconds with large strain.

In addition to its utility in fundamental research, this technology offers practical applications as well. For instance, doctors could use these devices as tiny medical implants to mechanically stimulate tissue or to actuate mechanisms for the on-demand delivery of biological agents.

Most plants have developed mechanisms to prevent self-fertilization and its detrimental effects of inbreeding depression. Traits promoting selfing in plants have been approached mainly from the perspective of a loss of function, or even only considered as a by-product of non-adaptive evolutionary processes. However, the shift from cross-fertilization to selfing has been identified as one of the most frequent evolutionary transitions. Therefore, adaptive mechanisms actively promoting selfing should be usual in the plant kingdom, but, remarkably, they have not been frequently found.

In "Anther Rubbing, a New Mechanism That Actively Promotes Selfing in Plants", Abdelaziz et al. describe anther rubbing, a mechanism based in autonomous, repeated, and coordinated movements of the stamens over the stigma during flower opening that promotes self-fertilization in a Brassicaceae species. The researchers use time-lapse video and micro-photography to document this novel reproductive mechanism. They also demonstrate experimentally that anther rubbing is sufficient to achieve maximal reproductive output in this plant. This mechanism is different from the known cases of delayed self-pollination because it assures self-pollination even before the flowers will be exposed to the visit of pollinators. This work demonstrates that elaborated mechanisms, including continuous and repeated movements, can evolve in plants to promote self-pollination. Since the evolution of mating systems in plants is a very active research field, this work will establish a new perspective in the study of the evolution of plant diversity and their mating system strategies.