Culture

For most vertebrates, losing a limb is permanent, but a lucky few species -- such as salamanders and tadpoles -- have the ability to completely regrow complex body parts. Understanding the molecular mechanisms underlying this phenomenon may be the key to developing new kinds of regenerative medicine, giving us the power to heal spinal cord injuries and other severely damaged tissues.

A new study published in the Proceedings of the Royal Society B from researchers at the University of Chicago and Universidade Federal do Pará explores this regenerative ability in the tails of West African lungfish for the first time, and finds that the process shares many of the same traits as tail regeneration in salamanders. Their results indicate that this trait was likely found in a common ancestor - and provide a new opportunity for better understanding and harnessing the mechanisms of limb regrowth.

The inspiration for this research grew out of a postdoctoral fellowship in the Shubin Lab at UChicago. After completing his postdoctoral studies in evolutionary biology, Igor Schneider, PhD, accepted a faculty position in Belém, Brazil, where he found the diversity of the Amazon rainforest at his fingertips. He became interested in exploring evolutionary traits in new animal models and ultimately narrowed his focus to regenerative biology. He began exploring mechanisms of regeneration in the lungfish - first in South American species, and then in West African lungfish.

"When we're talking about how a salamander regrows a lost tail, we're talking about regrowing all sorts of tissues," said Schneider, an Associate Professor of Biological Sciences at the Universidade Federal do Pará and a Visiting Associate Professor of Organismal Biology at UChicago. "Vertebrae, spinal cord, muscle, it's a very complex structure. Mammals, birds and most reptiles can't regenerate tissue like that, but salamanders can. We know some of the biology of how that happens, but we don't really know much about how it evolved, or when. Did our ancestors have the ability to regenerate a lost limb? Did we lose this capacity as mammals, or did salamanders get lucky enough to invent it later on?"

One way to answer this question is to determine whether or not the trait existed in the common ancestor between humans and salamanders. To do this, the researchers took a phylogenetic approach, looking for additional relatives that possess a similar regenerative trait. Lungfish are unique in that they are "our closest fish cousin," Schneider said. "They can regenerate their tails, but they are also our closest relative in the water. This lets us explore whether or not this regenerative ability was also likely to be present in our common ancestor, without having to go too deep into our phylogenetic tree."

Lungfish represent an ideal model for more reasons than one. "These animals have the right anatomy to study this question and can also be easily managed in the lab," said Neil Shubin, PhD, the Robert R. Bensley Distinguished Service Professor of Organismal Biology and Anatomy at UChicago. "Lungfish are much more closely related to humans than other common species that have regenerative abilities, like zebrafish. For instance, lungfish have a humerus in their fin, just like the bone in our upper arms. They have lungs that are similar to ours. There is a suite of characteristics suggesting that these animals are much more closely related to us than zebrafish."

The investigators were initially challenged with establishing the lungfish as a model from the ground up, learning how to care for the fish in a laboratory setting, sampling tissue and obtaining DNA sequencing data to get a clearer picture of the animal's genetics, and testing new antibodies and techniques in a brand-new species.

What they found was that the West African lungfish could not only fully regenerate a lost tail, but that the regeneration used similar molecular mechanisms to the limb regrowth seen in amphibians. This includes a critical signaling molecule, Shh, which plays a key role in the growth and organization of the brain and body during embryonic development. This provides support for the hypothesis that this type of regeneration was present in a common ancestor of these species -- and of humans.

But perhaps even more interesting than the similarities in regeneration processes are the differences. "What I found particularly intriguing were some of the aspects of tail regrowth that are unique to the lungfish," said Schneider. "These animals are known for having gigantic genomes -- up to 40 times as large as a human's -- because their genomes contain a lot of virus-derived DNA elements, called transposons. During regeneration, some of those genes turn on, but we don't know if it's just because they're close to other key genes in this process, or if it's because these genes are actively involved in regeneration. Some of this has been seen in amphibian regeneration as well, so it begs the question of whether or not these transposons play a particular role in regeneration."

In addition to providing insights on the evolutionary origin of this trait, the researchers say this new animal model will help further the field of regenerative medicine. "Often, when you have limited models, you'll try to understand a process very well in a given species, and then extrapolate what you learn to other species," Schneider said. "But you might encounter things that are unique to the species you're studying that won't always apply to other animals. Understanding phenomena like regeneration in a comparative way, looking at how other organisms are doing this, can help us find general themes in regeneration."

Further clarifying the evolution of limb regeneration in lungfish and other species, along with their underlying mechanisms, may uncover new treatments for severe wounds, spinal cord injuries and amputations. "Ultimately, we're trying to understand the ancestral tool kit used by these species to conduct the regeneration process," said Shubin. "This will help us figure out what parts of that tool kit we as humans have lost, at the genetic and cellular level, and more importantly, what parts can we recreate?"

The study, "Salamander-like tail regeneration in the West African lungfish," was supported by the Brazilian National Council for Scientific and Technological Development Universal Program (Grant 403248/2016-7), the CAPES-Humboldt Foundation Fellowship, CAPES/DAAD PROBRAL (Grant 88881.198758/2018-01), MCTIC/FINEP/FNDCT/AT Amazonia Legal to I.S. This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001. Additional authors include Kellen Matos Verissimo, Aline Cutrim Dragalzew, Sylvain Darnet, Wainna Renata Barroso Mendes, Ciro Ariel dos Santos Neves, Erika Monteiro dos Santos, Cassia Nazare de Sousa Moraes, and Josane de Freitas Sousa of the Universidade Federal do Pará; Louise Neiva Pereze of the Universidade Federal do Pará and the Leibniz Institute for Evolution and Biodiversity Science; Nadia Belina Fröbisch of the Leibniz Institute for Evolution and Biodiversity Science; Gayani Senevirathne of the University of Chicago; and Ahmed Elewa of the Karolinska Institute.

DALLAS - Sept. 15, 2020 - Conditions related to obesity, including inflammation and leaky gut, leave the lungs of obese patients more susceptible to COVID-19 and may explain why they are more likely to die from the disease, UTSW scientists say in a new article published online in eLife. They suggest that drugs used to lower inflammation in the lungs could prove beneficial to obese patients with the disease.

COVID-19, caused by the novel coronavirus SARS-CoV-2, varies widely in clinical severity: Some patients are asymptomatic while others have devastating forms that have led to more than 905,000 deaths worldwide.

Several pre-existing conditions have been shown to increase the risk of COVID-19 severity, including obesity and Type 2 diabetes - two conditions that often go hand-in-hand, says Philipp Scherer, Ph.D., director of the Touchstone Center for Diabetes Research and a professor of internal medicine and cell biology at UT Southwestern.

For example, he highlights the Dallas County data that reports the disturbing fact that 47 percent of patients who have died from COVID-19 from March to August had diabetes. In addition, 31 percent of patients hospitalized with COVID-19 in the county during that same period had diabetes and 17 percent were obese without diabetes (see graphic).

Correlations have been found in many other countries between obesity and COVID-19 deaths. However, the mechanisms behind why obesity contributes to severe COVID-19 are unknown.

Scherer and his colleagues, including Manasi Shah, M.D., an endocrinology fellow at UTSW, and Ilja L. Kruglikov, Ph.D., Dr.Sci., a researcher at Wellcomet GmbH in Karlsruhe, Germany, explore this phenomenon in the new opinion piece.

One idea for the increased risk, they suggest, is that fat has high amounts of ACE2 receptors, entryways for the SARS-CoV-2 virus on cells. The increased numbers of these receptors in obese patients could lead to a higher viral load, a factor thought to lead to poor outcomes for COVID-19 patients.

These ACE2 receptors can be shed into circulation and end up in the lungs, specifically increasing SARS-CoV-2 concentration in lung tissue. In addition, the increased ACE2 expression in obese individuals spurs an imbalance in chemical signals that induce inflammation, fibrosis, and leaky blood vessels, all of which have the potential to cause a more severe COVID-19 infection.

However, Scherer and his colleagues note other conditions linked with obesity are even more powerful contributors to increased disease severity. One of these is a higher overall inflammatory state that tends to accompany obesity, which primes many tissues - including the lungs - for a poor response to infection. Another is the "leaky gut" that's also typically present in obese individuals: Their intestinal cell lining develop gaps, allowing small amounts of intestinal contents to spill into circulation.

Among these contents leaking out are intestinal bacteria and their toxins, including lipopolysaccharide (LPS), a protein produced by gram-negative bacteria such as intestinal Escherichia coli that cause a severe inflammatory response. Studies have shown that obese individuals have elevated levels of both bacteria and LPS in their lung tissue - even in the absence of infection.

When these patients are infected with COVID-19, Scherer and his colleagues hypothesize, it pushes an already vulnerable system over the edge. Synergistic interactions between damage caused by the virus, damage already present from intestinal flora that migrated to the lungs from a leaky gut, and an elevated inflammatory state could lead to a more severe infection than in the absence of these factors.

"It's all about the system already being primed," Scherer says. "When the virus comes into this system, the lungs are already at risk. More damage and more inflammation could push these patients over the edge and cause a perfect storm."

He notes that dexamethasone, a steroid that's already shown promise in clinical trials, could be especially helpful in obese patients. This treatment reduces inflammation systemically, taking a broad approach to reducing this damaging state. A more targeted approach might be to use PPAR? agonists, a class of drugs that have multiple effects including lowering inflammation, reducing ACE2 expression, lowering blood sugar, reducing LPS levels in circulation, and preventing fat cells in the lung from converting into a fibrotic cell type that can impair breathing. Unlike dexamethasone, PPAR? agonists don't impair immunity and have fewer common side effects.

"There may be an overabundance of currently proposed treatments for COVID-19," Scherer says. "However, we believe our suggestions are very much based on facts and could have a high chance of improving outcomes while avoiding any harm."

Researchers at the Norwegian University of Science and Technology (NTNU) have found a completely new method to check the electronic properties of oxide materials. This opens the door to even tinier components and perhaps more sustainable electronics.

"We found a completely new way to control the conductivity of materials at the nanoscale," says Professor Dennis Meier at NTNU's Department of Materials Science and Engineering.

One of the best aspects of the new method is that it does not interfere with other properties of the material, like previous methods did. This makes it possible to combine different functions in the same material, which is an important advance for nanoscale technology.

"What's really great is that this project is being run from NTNU and involves people from several departments. We also benefit from key facilities like the NanoLab and the TEM (transmission electron microscopy) Gemini Centre. This interdisciplinary approach shows what we can do when we work together," Meier says.

A new article in the journal Nature Materials addresses the findings. The article has attracted international attention even before being printed.

The possibilities offered by the discovery were discussed in the August issue of Nature Materials by leading experts in the field.

We rarely think about the technology that lies behind turning on a light bulb or our use of electrical appliances. The control of charged particles on a minute scale is simply part of everyday life.

But on a much smaller nanoscale, scientists are now routinely able to manipulate the flow of electrons. This opens up possibilities for even smaller components in computers and mobile phones that use barely any electricity.

A basic problem remains, however. You can simulate nanoscale electronic components, but some of the most promising concepts seem mutually exclusive. This means that you can't combine multiple components to create a network.

"Utilizing quantum phenomena requires extreme precision to maintain the right ratio of different substances in the material while changing the chemical structure of the material, which is necessary if you want to create artificial synapses to simulate the properties of nerve pathways as we know them from biology," Meier says.

Collaborative interdepartmental efforts, led by Professor Meier, have succeeded in circumventing some of these problems by developing a new approach.

"The new approach is based on exploiting 'hidden' irregularities at the atomic level, so-called anti-Frenkel defects," Meier says.

The researchers have managed to create such defects themselves, thus enabling an insulating material to become electrically conducting.

Defects in the material are related to its various properties. However, the anti-Frenkel defects can be manipulated in such a way that changes in the conductivity do not affect the actual structure of the material or change its other properties, such as magnetism and ferroelectricity.

"Maintaining the structural integrity makes it possible to design multifunctional devices using the same material. This is a big step towards new technology on a nanoscale," says Meier.

The research team includes Professor S. M. Selbach from the Department of Materials Science and Engineering, Professors Antonius T. J. van Helvoort and Jaakko Akola and Associate Professors Per Erik Vullum and David Gao from the Department of Physics, and Associate Professor Jan Torgersen from the Department of Mechanical and Industrial Engineering.

Another advantage of the new approach is that researchers can erase components on a nanoscale using a simple heat treatment. Then you can change or upgrade the components in the material afterwards.

"Maybe we'll be able to use our electronic gadgets longer instead of recycling them or throwing them away. We can just upgrade them instead. This is fundamentally much more environmentally friendly," Meier says.

Planning is already underway for further attempts to combine different components. This work will be carried out by the FACET group at NTNU's Department of Materials Science and Engineering.

The work is supported by the European Research Council through an ERC Consolidator Grant that Meier received last year. The renowned Center for Quantum Spintronics (QuSpin) is also involved. The goal is to utilize both charge and spin in the electrons to give us a more environmentally friendly future.

"You have to eat!" It's a sentiment that illustrates how central food is to Italian culture, but the woman who uttered these words also happens to be struggling with bulimia nervosa.

Carmela* is one of many Italian-Australian women who has a conflicted relationship with food which is inextricably linked to culture, according to University of South Australia researcher Michelle Caruso.

The social work PhD student has undertaken the first study looking at how Italian culture can influence women's experiences of disordered eating in contemporary Australia.

In her interviews with Italian-Australian women in Adelaide, Caruso explored how many of the women were 'plied with food' as young children, with meals linked to family, culture and identity.

"Many of these women were not allowed to determine their own food consumption during childhood, adolescence and even into adulthood," Caruso explains. "Food was habitually pushed and forced onto them, resulting in early conflicts which have manifested as eating issues in their later years."

She deliberately uses the term "disordered eating," linking it to culture, in contrast to "eating disorder," which infers a medical or psychiatric condition.

"Women diagnosed with binge eating, anorexia nervosa and bulimia nervosa are typically treated based on psychiatry. One of the greatest weaknesses of the psycho-medical approach is its failure to contextualise the disordered eating experiences of women from diverse cultural backgrounds," Caruso says.

The researcher chose Italian women for her study, but her findings could equally apply to many other migrant women with entrenched cultural beliefs around food, she says.

Previous research shows that Italian women have a higher prevalence of disordered eating than women in comparable European countries such as Spain, Germany and the Netherlands.

Caruso identified three key themes central to the women in her study: "il cibo è tutto, il cibo è amore" (food is everything, food is love), "fare la bella figura" (to make a good impression), and "il mio piatto" (it's my plate).

"All expressions illustrate the significant cultural symbolism and meanings attached to food in Italy. In the Italian culture, everything is cooked with love. Food and feeding are important processes which help build and maintain relationships, connections and a sense of home and belonging," Caruso says.

"The childhood memories of the women I interviewed are mostly positive, connected to pleasure, love, safety, protection and comfort. But the women also expressed a sense of lacking autonomy, control and personal power associated with their consumption of food. This led to an ongoing complex, conflicted connection with food.

"Through their disordered eating experiences, the women in this study were able to construct a sense of power, control and self-agency, where they were able to decide what to consume or reject."

The relationship with food is so central to the Italian culture that many families are unwilling to accept that food has anything but positive connotations, Caruso says.

"In the eyes of an Italian mother or grandmother, rejecting food is akin to personal rejection. And because women with disordered eating don't want to bring shame or embarrassment on their family, they are unlikely to admit they have a problem and know their family probably won't accept it if they do try to discuss it."

Australia - like many western cultures - puts a high value on female thinness, while Italian culture values food and eating together, placing significant conflicting pressures on women from Italian backgrounds, Caruso says.

"Migrants hold onto their food practices so tightly when they migrate to another country. It's a way of staying connected with their identity and their culture."

Caruso says it's time that health practitioners and ethnic communities recognised the part that culture plays in disordered eating and ensured that women were given the appropriate support.

Humans, like other animals, have the ability to constantly adapt to new situations. Researchers at the Brain Research Institute of the University of Zurich have utilized a mouse model to reveal which neurons in the brain are in command in guiding adaptive behavior. Their new study contributes to our understanding of decision-making processes in healthy and infirm people.

Greetings without handshakes, mandatory masks in trains, sneezing into elbow crooks - the COVID-19 pandemic dramatically illustrates how important it can be for humans to shed habitual behaviors and to learn new ones. Animals, too, must be capable of rapidly adapting to changes in environmental conditions.

"The plasticity of the brain forms the foundation of this ability," says Fritjof Helmchen, the co-director of the Brain Research Institute at the University of Zurich, who also heads the Neuroscience Center Zurich. "But the biological processes that enable this amazing feat are still poorly understood." Helmchen's team has now successfully taken a first step towards illuminating these processes. Their study, just published in the scientific journal Nature, demonstrates that the orbitofrontal cortex, a region of the cerebral cortex that sits behind the eyes, is capable of reprogramming neurons located in sensory areas.

Observing brain cells in the act of relearning

In their experiments with mice, the researchers simulated a relearning process under controlled conditions and investigated what happens in the brain at the level of individual neurons during that process. The researchers first trained the animals to lick every time they touched a strip of coarse-grit sandpaper with their whiskers and rewarded the response with a drink of sucrose water. However, the mice were not allowed to lick when they brushed their whiskers against fine-grain sandpaper; if they did, they were punished with a mild irritating noise. Once the mice understood how to perform their task, the tables were then turned. The reward was now delivered after whisking against fine-grain and not coarse-grit sandpaper. The mice quickly learned this new, opposite behavior pattern after little practice.

A higher authority remaps cells

During the training, the neuroscientists employed molecular biological and imaging techniques to analyze the function of individual neurons in the brain cortices involved. Their analysis revealed that a group of brain cells in the orbitofrontal cortex is particularly active during the relearning process. These cells have long axons that extend into the sensory area in mice that processes tactile stimuli. The cells in this area initially followed the old activity pattern, but some of them then adapted to the new situation. When specific neurons in the orbitofrontal cortex were deliberately inactivated, relearning was impaired and the neurons in the sensory area no longer exhibited modification in their activity.

"We were thus able to demonstrate that a direct connection from the orbitofrontal cortex to sensory areas of the brain exists and that some neurons get remapped there," explains Helmchen. "The plasticity of those cells and the instructions they receive from the higher-order orbitofrontal cortex appear to be crucial to behavioral flexibility and our ability to adapt to new situations."

"It has long been known that the orbitofrontal cortex is involved in decision-making processes". It is in charge, to a certain degree, of enabling us to react appropriately and successfully to exogenous circumstances. "But the neural circuits underlying this function were unknown until now," says Abhishek Banerjee, lead author of the study, now an Associate Professor at Newcastle University, UK. "This mode of communication and control across distant areas of the brain is truly remarkable."

Understanding disorders better

The researchers believe that the fundamental processes they observed in mice take place in a similar way in the human brain as well. "This deepened knowledge about complex brain processes involved in decision making is important," explains Helmchen. "Our research findings may contribute to a better understanding of brain disorders in which the flexibility in decision making is impaired, as it is, for example in various forms of autism and schizophrenia." Clearly, he says, having difficulties or being unable to adapt one's behavior poses a severe problem for affected people.

Researchers at the Western Pacific Tropical Research Center at the University of Guam have documented what biologists call a "host shift" of the coconut rhinoceros beetle in Guam. The beetle, first documented as an invasive species in Guam in 2007, has been devastating the island's ubiquitous coconut trees and is now also burrowing into Guam's endangered native cycad tree, Cycas micronesica. The results were published in June in Volume 13 of the Communicative & Integrative Biology journal.

The fact that coconut trees were the second most abundant tree on the island prior to the beetle's invasion was one factor that enabled the beetle's explosive population growth. The sustained efforts to develop an effective biological control program have not been effective, allowing the pest to establish a foothold throughout the island.

"Our initial alarm after documenting the CRB burrowing activity on cycad trees was the fact that Guam's cycad species was actually the most abundant tree on the island only 20 years ago," said Irene Terry, one of the authors of the study. "Where else have the most abundant and second most abundant forest species been threatened by the recent invasion of one non-native herbivore?"

The authors used direct measurements of starch concentrations of the plant tissues to show that the island's heavily damaged coconut trees have declined in starch content so greatly that the host shift may have occurred in order to exploit the large doses of starch that are available in the cycad stems.

"The CRB behaviors that we documented fit the 'ecological fitting theory,' which states that shifting to a new host species is due to compatible resources or signals in the new host," said Terry, who has been studying the relationships among insect herbivores and the native cycad plant since 2005. This kind of host shift is opportunistic and may occur without any co-evolution processes.

Prior to the beetle's host shift, the cycad population on Guam was already suffering from chronic damage by numerous non-native insect and mammal herbivores, resulting in 96% mortality of the cycad population in the past 15 years. The WPTRC cycad team's sustained research has revealed that the severity of damage by each herbivore species has exhibited an undulating pattern, with the most severe damage at any point in time changing from species to species.

"When the CRB damage in our managed gardens began showing up on several cycad species, we knew that it was only a matter of time before the CRB host shifts included Guam's native cycad," said Benjamin Deloso, who curates the University of Guam's interpretive cycad garden.

The beetle's burrowing activity in managed gardens at the University of Guam also includes highly diverse cycad species that originate from Asia, Australia, Central America, and the Caribbean regions.

"The damaged species included two families and four genera, so the dietary needs of the coconut rhinoceros beetle appear to be met at the cycad Order level," Deloso said.

The unexpected addition of the coconut rhinoceros beetle to the list of cycad herbivores reveals the need for continued observation of the cycad population by species experts so conservationists can best understand which of the threats are most in need of mitigation.

The authors discussed the absence of international cycad experts from the contemporary conservation projects as a component of why the damage from the beetle was able to become established throughout the island without notice, and the continued absence of international experts from ongoing funded conservation projects will increase the probability of local extinction of the only native gymnosperm species in the region.

Researchers have shown how industries could work together to recycle cigarette butts into bricks, in a step-by-step implementation plan for saving energy and solving a global littering problem.

Over 6 trillion cigarettes are produced each year globally, resulting in 1.2 million tonnes of toxic waste dumped into the environment.

RMIT University researchers have previously shown fired-clay bricks with 1% recycled cigarette butt content are as strong as normal bricks and use less energy to produce.

Their analysis showed if just 2.5% of global annual brick production incorporated 1% cigarette butts, this would offset total cigarette production each year.

The research team has now developed a detailed plan for bringing the brickmaking and waste management industries together, to implement cigarette butt recycling into bricks at mass scale.

Lead researcher Associate Professor Abbas Mohajerani said cigarette butts were saturated with toxic chemicals, including over 60 known to cause cancer.

"Firing butts into bricks is a reliable and practical way to deal with this terrible environmental problem, while at the same time cutting brickmaking production costs," Mohajerani said.

"We need to do far more to stop cigarette butts from polluting our streets, rivers and oceans, and prevent them leaching harmful toxins into our environment.

"Our ultimate goal is a world free of cigarette butt pollution: our industry implementation plan outlines the practical steps needed to bring this vision to reality."

The plan, published in a special issue of the journal Materials, shows how cigarette butts can be collected and recycled on an industrial scale.

Different incorporation methods are outlined - using whole butts, pre-shredded butts, or a pre-mix where the butts have already been incorporated into other brickmaking materials.

Requirements for maintaining health and safety are also methodically detailed, with analysis showing how risks can be mitigated for both industrial brickmaking and handmade bricks.

The new study also details for the first time the types of harmful bacteria found on cigarette butts, analyses how heavy metals can leach from them into the environment and examines the energy value of butts in the brickmaking process.

Energy savings

By analysing the butts' energy value, the team in the School of Engineering at RMIT showed the incorporation of 1% cigarette butt content would reduce the energy required to fire bricks by 10%.

"It takes up to 30 hours to heat and fire bricks, so this is a significant financial saving," Mohajerani said.

It can take many years for cigarette butts to break down, while heavy metals like arsenic, chromium, nickel and cadmium trapped in the filters leach into soil and waterways.

During firing, however, these metals and pollutants are trapped and immobilised in the bricks.

Bricks made with cigarette butts are also lighter and provide better insulation - meaning reduced household heating and cooling costs.

About 25 to 30 billion filtered cigarettes are smoked in Australia each year, with about 7 billion butts littered.

Mohajerani, who has spent over 15 years researching sustainable methods for cigarette butt recycling, has also developed technology for incorporating butts into asphalt concrete.

He said the technical solutions would need to be backed up by more stringent laws and harsher littering penalties.

"Local authorities would also need to provide more specialised bins for cigarette butts, to both prevent littering and enable smooth collection for the brickmaking process," he said.

"My dream is a dedicated brickmaking recycling facility in every country, that can recycle butts and solve this pollution problem for good."

Climatic conditions are changing at an unprecedented rate, affecting mainly fish, amphibians and reptiles, ectothermic animals that are unable to generate their own internal heat. With heat waves and rising temperatures, these organisms experience not only increased growth rates and heat stress, but also further ageing.

Fish, amphibians and reptiles are animals known as ectotherms, which means they cannot actively control their internal temperature and are regulated by that of the environment. Faced with an increase in temperature caused by climate change, these organisms will experience a rise in their body temperature that will have serious consequences for them.

In fact, environmental changes are already altering them, as several studies have shown over the last few years. Their growth rates are already faster when temperatures are higher, and they are subject to heat stress from extreme events such as heat waves.

"Heat waves take animals out of their thermal preferences, to the point even of reaching their temperature tolerance limits. The longer and more frequent the heat waves, the greater their impact on the physiology of ectotherms," Germán Orizaola, researcher at the Joint Institute for Biodiversity Research of the University of Oviedo, explains to SINC.

Now, this expert, together with an international team of scientists, has reviewed other effects of the temperature increase on fish, amphibians and reptiles in the scientific literature. The results of this opinion article, published in the journal Global Change Biology, suggest that there will be a climate change impact on their ageing rates.

"Higher growth rates will generate physiological imbalances in ectotherms, increasing, for example, oxidative damage to the proteins and DNA, which may also affect the telomeres, the repeated sections of non-coding DNA located at the ends of chromosomes," says Orizaola.

Telomeres, which provide stability and protect coding sequences from loss at the end of the chromosome, can be shortened or lost each time a cell splits. The faster a cell divides and the higher the levels of oxidative stress, the faster the length of the telomere is eroded.

"As telomeres protect DNA, the faster the telomeres are lost, the faster the cells degrade and the body ages. This clear link between climate change and ageing is described for the first time in our article," the researcher explains.

Shorter life expectancy in populations

This rapid ageing caused by climate change can have serious consequences for natural populations. "One rather clear consequence is that if the life expectancy of individuals in a population is reduced, their ability to produce offspring may be compromised," warns Orizaola.

With a reduced lifespan, any external phenomenon such as a severe drought, flood, disease, or heat wave will reduce the recovery capacity of populations and the time to produce enough offspring will decrease. Furthermore, as scientists stress, the effects on the ageing of a species can affect other species that are part of its ecological network, for example, if it affects the number of prey, competitors, parasites, etc.

"This is a field that has barely been explored so far, but everything indicates that it could be another of the possible problems facing wildlife that is exposed to climate change," stresses the co-author from the University of Oviedo. To his mind, knowing the effects of the climate crisis on ectotherm ageing would help to design better conservation and management programmes.

"For example, if a species (say, a fish) is caught for commercial reasons, it is important to know that climate change can reduce its lifespan when catch rates are defined and population demographics are evaluated," he says.

On the other hand, species that are already endangered and with a small population size may be even more threatened if life expectancy is to be reduced, so conservation measures should be implemented. With other species, whose habitat may be affected by rising temperatures, "it may be necessary to consider relocating these individuals to a more suitable habitat," the scientist concludes.

Using the X-ray laser European XFEL, a research team has investigated how water heats up under extreme conditions. In the process, the scientists were able to observe water that remained liquid even at temperatures of more than 170 degrees Celsius. The investigation revealed an anomalous dynamic behaviour of water under these conditions. The results of the study, which are published in the Proceedings of the National Academy of Sciences (PNAS), are of fundamental importance for the planning and analysis of investigations of sensitive samples using X-ray lasers.

European XFEL, an international research facility, which extends from the DESY site in Hamburg to the neighbouring town of Schenefeld in Schleswig-Holstein, is home to the most powerful X-ray laser in the world. It can generate up to 27 000 intense X-ray flashes per second. For their experiments, the researchers used series of 120 flashes each. The individual flashes were less than a millionth of a second apart (exactly 0.886 microseconds). The scientists sent these pulse trains into a thin, water-filled quartz glass tube and observed the reaction of the water.

"We asked ourselves how long and how strongly water can be heated in the X-ray laser and whether it still behaves like water," explains lead author Felix Lehmkühler from DESY. "For example, does it still function as a coolant at high temperatures?" A detailed understanding of superheated water is also essential for a large number of investigations on heat-sensitive samples, such as polymers or biological samples.

"With the X-ray flashes, we were able to heat the water up to 172 degrees Celsius within a ten thousandth of a second without it evaporating," reports Lehmkühler. Such a boiling delay can normally only be observed up to about 110 degrees Celsius. "But that is not the only anomalous feature," the physicist emphasises. The scientists investigated the movement of silicon nanospheres floating in the water as markers for the dynamics in the sample. "In the extremely overheated water, we observed that the movement of silicon dioxide nanospheres deviated significantly from the expected random Brownian molecular movement. This indicates an uneven heating of the sample," says Lehmkühler. Existing theoretical models cannot yet satisfactorily explain this behaviour because they are not designed for water under these extreme conditions.

Thanks to the rapid flash sequence of the European XFEL, the researchers were able to observe the process in extreme detail. "What makes the European XFEL unique is the high repetition rate, that is, the high number of pulses per second", explains co-author Adrian Mancuso, head of the SPB/SFX instrument at the European XFEL where the experiments took place. "And we have all the instrumentation in place - such as fast cameras, diagnostics and more - to make these experiments possible". For instance, the Adaptive Gain Integrating Pixel Detector (AGIPD) developed by a DESY-led consortium can take around 350 serial images at intervals of only 220 billionths of a second (nanoseconds).

This setup not only allowed the superheated water to be generated, but also enabled the scientists to carry out precisely controlled series of experiments with X-ray flashes of reduced intensity. "Using silicon filters, we fine-tuned the energy of the pulses so that we were able to control exactly how much the water was heated," reports Lehmkühler. "For example, we were able to determine how strong the X-ray flashes should be so that the temperature of an aqueous sample remains more or less constant".

This enables researchers to better plan experiments with heat-sensitive samples at the X-ray laser, for example. On the other hand, the heating effect can also be used in a targeted manner if its exact course is known. The team plans to further investigate these effects also within the framework of the Centre for Molecular Water Science (CMWS), which is currently being set up at DESY.

"Our results not only provide the surprising observation of an anomalous dynamic, but also draw a detailed picture of how aqueous samples heat up in the X-ray laser," summarises lead researcher Gerhard Grübel from DESY, one of the CMWS coordinators. "In addition, the investigations prove that such serial images are possible at the European XFEL and that its flashes are extremely uniform in every pulse train".

These results from studies in both experimental and theoretical physics may help to improve antibacterial surfaces. The research work was recently published in the journal 'Nanoscale'.

Staphylococcus aureus bacteria are one of the most common causes of infections acquired by patients during a stay in hospital. These pathogens are particularly problematic because they can form robust biofilms on both natural and artificial surfaces from which they are very difficult to remove. 'The individual bacteria within these biofilms are effectively protected from attack by antibiotics or by the human immune system. That's why it can be so dangerous when these bacteria colonize medical implants as they can then cause serious post-operative infections,' explains Karin Jacobs, Professor of Experimental Physics at Saarland University. It is therefore crucial to try and prevent these biofilms from forming in the first place.

However, to be able to influence biofilm growth, the researchers had to understand the mechanisms by which the bacteria adhere to different materials. Using a scanning atomic force microscope, they pressed the minute bacterial cells onto different types of surfaces and then determined the force needed to lift the adhered cells from the surface. This experimental configuration allowed the researchers to record what are known as force-distance curves. 'We used extremely smooth silicon surfaces as model surfaces. In one set of experiments, the silicon surfaces were prepared so that they had high water-wettability; in another set of experiments they were treated to be highly hydrophobic. We were able to show that the bacterial cells adhered far more strongly to the hydrophobic surfaces, from which water simply rolled off, than on the hydrophilic (water-wettable) surfaces,' explains Karin Jacobs. But it is not just the magnitude of the forces that differ between the two surface types, so too do the shapes of the force-distance curves (see figure). 'On the hydrophobic surfaces, we see very smooth curves with a characteristic cup shape. On the hydrophilic surfaces, in contrast, we observe force-distance curves with a very jagged profile,' says Professor Jacobs.

In order to understand these results, the dynamics of these complex systems were modelled using Monte Carlo simulations that were carried out in the research group led by Professor Ludger Santen, Professor of Theoretical Physics at Saarland University. The model treats the bacterial cell as a rigid sphere and the molecules in the cell wall that tether the cell to the surface as minute springs. 'It turns out that in order to reproduce the experimental results, the role played by the random (stochastic) nature of the molecular binding process is more important than trying to increase the complexity of the model. We have now uncovered why the bacteria cells behave so differently on different types of surfaces. On hydrophobic surfaces, a large number of the cell wall proteins adhere to the surface, which results in a strong binding force and yields a smooth force-distance curve,' explains Ludger Santen. In contrast, on a hydrophilic surface, far fewer cell wall proteins are involved in tethering the bacterium to the surface. As a result, the bacteria are held less strongly on the surface and the shape of the force-distance curve is less uniform. 'The jagged shape of the curves that we see with hydrophilic surfaces is caused by a few individual cell wall molecules as they are pulled from the surface. Because fewer cell wall proteins are involved, the bacteria bind less strongly to hydrophilic surfaces,' says Erik Maikranz, who carried out the Monte Carlo simulations as part of his doctoral research work.

Due to the different shapes of the force-distance curves, the physicists suppose that on a hydrophilic surface fewer cell wall proteins are involved in the binding process because these molecules first have to overcome a potential barrier, which effectively reduces the number of protein macromolecules that can tether the cell to the surface. 'The potential barrier to adhesion on hydrophilic surfaces is relatively high, so only a few of the cell wall proteins are able to overcome this energy barrier in a particular time. On hydrophobic surfaces, however, the barrier is negligibly small, so that many cell wall proteins can adhere directly to the surface,' explains Dr. Christian Spengler, who performed the experiments in the study.

PITTSBURGH, Sept. 16, 2020 - People with one of the most common heart disorders who are exposed to greater levels of pollution have a 1.2-fold higher risk of stroke than their peers who live with less pollution, according to a JAMA Network Open study published recently by researchers at the UPMC Heart and Vascular Institute and University of Pittsburgh School of Medicine.

The study is the largest of its kind to include neighborhood-specific pollution data--rather than simply hospitalization data--and further emphasizes the importance of air pollution alerts in advising the activities of people with certain heart conditions.

"We measured pollution exposure at people's doorsteps by using geocoding and then determined their annual exposure to particulate matter. This approach and the sample size make our study particularly powerful," said Jared W. Magnani, M.D., M.Sc., UPMC cardiologist and associate professor of medicine at Pitt. "We can use this information to guide our patients by advising them to limit exposure to pollution. For example, we can notify those with atrial fibrillation to avoid being outside on days with unhealthy air quality, which may reduce their risk of stroke."

Magnani and his colleagues followed more than 31,000 people living in Allegheny County since 2007 with atrial fibrillation (AFib), a common heart rhythm disorder affecting at least 2.7 million Americans. Using suitcase-sized air pollution monitors mounted on telephone poles, the team was able to measure the exact levels of fine particulate pollution--soot--that the participants were breathing on a daily basis. The Pittsburgh region is ranked by the American Lung Association as one of the 10 most polluted in the U.S.

The researchers found that stroke risk steadily increased with higher daily exposure to air pollution. People with AFib already are at five times the risk of stroke, so the additional risk posed by fine particulate pollution is particularly concerning, Magnani noted.

"Our results advance the understanding of how air pollution impacts public health and strengthens the argument for continued advocacy to curb pollution," he said. "Fine particulate pollution is very small--it is able to get into our bodies through our lungs and into our blood stream where it can trigger heart events."

The team went on to examine the impact of pollution on different demographic and socioeconomic groups. They found that fine particulate exposure is 1.5-fold higher in blacks compared to whites, and 1.3-fold higher in those living below poverty versus above.

"Pollution exposure correlates with socioeconomic position, as people living closer to industrial sources tend to be lower income and minoritized. Hence, air pollution worsens racial disparities in health outcomes, due to the increased residential exposure," Magnani said. "Our study indicates the importance of modifying pollution as a risk factor for adverse health outcomes."

Magnani said future research will explore how individual factors--such as physical activity, diet, health care access and medication--might interact with pollution levels to modify stroke risk for people with AFib.

Overall, scientists from 24 countries and regions contributed, including the United Kingdom, Saudi Arabia, the Netherlands, the United States, Greece, Germany, Brazil, Pakistan, Malaysia, Australia, Argentina, Georgia, Romania, Armenia, Chile, China (with Hong Kong as a separate participant), Turkey, Italy, and Mexico. Overall, 5,320 students have been polled. Associate Professor of the KFU's Department of Pedagogical Psychology Olga Lopukhova was one of the participants.

"It's well established that men and women differ in their self-perception, values, and personality traits, as well as stereotypes held with regards to representatives of one or the other sex," she explains. "Men typically find themselves more active, whereas women think of themselves as more sociable. The paper pays attention to how such effects differ between cultural groups with the focus on self-construal and depressive symptoms."

It turns out that women are more depressive, especially in societies with low gender equality rankings. Furthermore, the research showed a slightly different picture of sex differences in self-assessment among students than could be inferred from previous such polls.

"In all sampling groups, we cannot find proof of sex differences in a culture as a whole. Instead, we can see that women see themselves as more interdependent in the conditions of low gender equality and more independent in high gender equality. Men self-assess as more closed, whereas women feel more connected with others. There are no noticeable sex differences in the other two parameters of self-construal or in depressive symptoms," continues the interviewee.

In the Russian version, the researchers added the interaction of the congruence of students to the culture type and their inclusion into social groups with their psychological wellbeing.

"The problem of psychological wellbeing and its factors becomes more and more popular in Russian and overseas research in light of the ever complicating conditions of personality adaptation to the fast-changing values, social norms, types of behavior, and interaction," says Lopukhova. "Students are such a social group prone to the risks psychological non-wellbeing because of age factors, their changing social standing, and exposedness to adaptation and information overloads."

Becoming is a student is often inextricably linked with a change in cultural environment, be it moving to another country or city or moving from countryside to an urban dwelling. In any case, a student needs to go through adaptation and acculturation processes while starting their studies.

The Kazanian part of the poll comprised 488 respondents, 249 of whom were female and 239 male, aged from 18 to 28 years, from various universities of the city. The results showed that students with median congruence-to-culture ratios showed better psychological wellbeing. About a third of students had pronounced depressive symptoms and unsteady self-esteem, which calls for more attention to psychological support.

As KFU researchers found, the congruence (internally non-contradictory acceptance) of the normative values of the cultural environment is a cultural predictor of subjective wellbeing. Conversely, non-congruence, i. e. non-acceptance of behavioral norms, is a predictor of non-wellbeing and heightened depressive symptoms. Inclusion in social groups is also a predictor.

Overall, the presence of depressive symptoms is highly dependent on cultural congruence, whereas self-esteem is not.

When we talk of Nordic history, it is all but impossible not to mention the Vikings. Stories about the Scandinavian warriors and their Old Norse Gods have long since travelled all around the world. But perhaps part of that narrative is only based on myths and brought to life by popular culture. At least, this is what is indicated by a new study from the University of Copenhagen.

The study is the biggest genetic study of Vikings ever. The researchers have sequenced the genome of 442 bone fragments from the Viking Age, from all over Europe, and they have made some rather surprising discoveries. Among other things, the Vikings may not be quite as Nordic as hitherto believed.

"The Vikings had a lot more genes from Southern and Eastern Europe than we anticipated. They frequently had children with people from other parts of the world. In fact, they also tend to be dark-haired rather than blond, which is otherwise consider an established Viking-trait," Professor at Lundbeck Foundation Center for Geogenetics at the GLOBE Institute at the University of Copenhagen, Eske Willerslev, explains.

Peasants missed out on the Bronze Age

The new study also reveals that generally Vikings were a lot more genetically diverse than the peasant societies on the Scandinavian mainland.
"The Vikings lived in coastal areas, and genetically speaking, they were an entirely different people to the peasant societies living further inland. The mainland inhabitants had a lot less in common with the Vikings than the peasants who lived in Europe thousands of years ago. You could almost say that genetically speaking, the peasants missed out on the entire Iron and Bronze Age," co-author of the study and Assistant Professor at the Center For Geogenetics at the GLOBE Institute, Ashot Margaryan explains.

However, the Viking's diverse genome stems not merely from people from elsewhere travelling to their settlements. In fact, they were themselves avid travellers, and historically, we know them best for their plundering and murdering raids abroad. But this genetic study sheds new light on who went where.

"The Danish Vikings went to England, while the Swedish Vikings went to the Baltic and the Norwegian Vikings went to Ireland, Iceland and Greenland. However, the Vikings from these three 'nations' only very rarely mixed genetically. Perhaps they were enemies or perhaps there is some other valid explanation. We just don't know," Ashot Margaryan says.

A Viking on the outside, a Scotsman on the inside

The new study also discards what we think we know about who actually went on raids together. Researchers have been able to find out more about this at a gravesite in Estonia, where raiding Vikings were brutally murdered.

"Popular culture suggests that the Viking Chief would recruit the strongest warriors from neighbouring tribes or communities to join him on a raid somewhere. But at least five of the Vikings in this grave are closely related. So perhaps you just brought your family along when you went on a raid," Eske Willerslev explains.

Vikings were not always murdered though; they fared better in other places. In England, by way of example, it has been possible to trace an influx of people from Scandinavia by studying language and specific place names. And the new study shows that in some of those places, the inhabitants actually embraced the entire Viking culture.

"In Scotland there's a grave, which in archaeological terms would be classified as a Viking grave. Its swords and symbols reflect the Viking culture. However, genetically speaking, the man in the grave has nothing in common with the Vikings. He is an example of how the Viking culture was embraced in certain places," Eske Willerslev elaborates.

And the new study not only discards popular ideas about Vikings, from time to time, scientific circles have also discussed the Viking Age.

"Some researchers and intellectuals have been of the opinion that in the North, we have a tendency to romanticize the Viking Age, because it is our own, and a very specific history. They have argued that the Viking Age wasn't really an Age at all, but rather part of the Iron Age. However, with this new study we're able to establish that the Viking Age was indeed something special. The Vikings travelled much farther, had lots of Southern European genes and were very likely part of a much more extensive cultural exchange with the rest of the world than any contemporary peasant society," Eske Willerslev concludes.

Researchers at Trinity College Dublin have examined the sustainability of different models of the most commonly used oral health product - the toothbrush - to ascertain which is best for the planet and associated human health.

Although the toothbrush is a widely recommended healthcare device worldwide, there is currently little quantitative data available for its impact on the planet. The research study, in collaboration with Eastman Dental Institute at University College London, is published in the British Dental Journal today (Tuesday, 15th September 2020). It represents the first time a life-cycle assessment (LCA) has been used to measure environmental consequences of a healthcare product.

Healthcare is a major emitter of environmental pollutants that adversely affect health, but awareness of these effects remains low both in the industry and in the general consumer population. There is currently little evidence or guidance regarding the sustainability of specific healthcare interventions, services or devices.

Researchers considered different manufacturing models of the toothbrush and measured the environmental impact (carbon footprint) and human health impact (DALYS) of the toothbrush. The electric toothbrush, the standard plastic brush, the plastic brush with replaceable head, and the bamboo brush were used. The team found that the electric toothbrush was comparatively harmful for planetary health.

The findings highlight the human health burden of the toothbrush manufacturing process. The electric toothbrush causes 10 hours of disability measured in Disability-Adjusted Life years or DALYS mainly for the people associated with the process of making and producing the devices. This is five times higher than a normal plastic brush.

The team found that the most environmentally sustainable toothbrush was not bamboo, as could perhaps be popularly believed, but a hypothetical continually recycled plastic toothbrush.

This simple comparative LCA showed that a plastic manual replaceable head toothbrush and bamboo manual toothbrush perform better than traditional plastic manual and electric toothbrushes in every environmental impact outcome measure used in this study. These results could be used to inform individual consumer choice, oral health recommendations, procurement of toothbrushes for public health programmes, and toothbrush manufacturers. Using LCA to inform healthcare policies and recommendations will help healthcare providers move towards a more environmentally sustainable system.

Dr Brett Duane, Associate Professor in Public Dental Health at Trinity College and lead researcher said:

" There are billions of toothbrushes used and discarded every year. Our research shows that electric toothbrushes are actually harmful for the planet and to the people involved in the manufacturing process and distribution. There is not a lot of evidence to show they are more effective unless you struggle to clean your teeth with a normal toothbrush. We have also shown bamboo toothbrushes are not the answer. Using them just stops land from being put to better use such as helping biodiversity, or in growing forests to offset carbon emissions.

The ideal toothbrush is one which uses plastic which is recycled in a continuous process. Plastic brushes which can be recycled don't take up a lot of land and they don't need lots of water to grow. The important thing here is to keep the plastic in the recycling chain. We need a system where plastic toothbrushes can be collected like batteries and then recycled into new products. If the plastic escapes the recycling chain, it needs to be able to be easily and naturally broken down into harmless products.

Manufacturers, consumers, health professionals, and health policy makers should consider environmental sustainability as well as money and people's health when recommending products. Governments and industry should consider how they could support recycling programmes. More funding is also required to support sustainability research in this area."

3D printing has driven innovations in fields ranging from art to aerospace to medicine. However, the high-energy ultraviolet (UV) light used in most 3D printers to cure liquid resins into solid objects limits the technique's applications. Visible-light curing, which would be more appropriate for some uses, such as tissue engineering and soft robotics, is slow. Now, researchers reporting in ACS Central Science have developed photopolymer resins that boost the speed of visible-light curing.

With the help of computer-aided design, 3D-printed objects are made by the successive layering of a material into a 3D shape, with each layer solidified or "cured" using UV light. Being able to use visible light for curing would have advantages, including reduced cost, improved biocompatibility, greater depth of light penetration and reduced light scattering. These attributes could open up new applications for 3D printing, such as making opaque composites, multi-material structures or hydrogels containing live cells. However, because visible light is lower in energy than UV, visible-light curing is currently too slow to be practical. Zachariah Page and colleagues wanted to find a way to speed up the process.

The researchers developed violet-, blue-, green- and red-colored resins that contained a monomer, a photoredox catalyst (PRC), two co-initiators and an opaquing agent. When the PRC absorbed visible light from LEDs, it catalyzed the transfer of electrons between the co-initiators, which generated radicals that caused the monomer to polymerize. The opaquing agent helped confine curing to the areas struck by light, which improved spatial resolution. The optimized mix of components allowed the researchers to print stiff and soft objects with small features (less than 100 μm), mechanical uniformity and build speeds up to 1.8 inches per hour. Although the best build speed is still less than half that of the fastest rate obtained using UV light, it could be further improved by increasing the light intensity or adding other components to the resin, the researchers say.

The authors acknowledge funding from the U.S. Department of Defense and the Welch Foundation.

The article that accompanies this paper is freely available as an ACS AuthorChoice article here.

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