Earth

Cell therapies hold great promise for revolutionizing the treatment of cancers and autoimmune diseases. But this multibillion-dollar industry requires long-term storage of cells at super-cold cryogenic conditions, while ensuring they'll continue to function upon thawing. However, these cold temperatures trigger the formation and growth of ice, which can pierce and tear apart cells. Research published in the Journal of the American Chemical Society by University of Utah chemists Pavithra Naullage and Valeria Molinero provides the foundation to design efficient polymers that can prevent the growth of ice that damages cells.

Nature's antifreeze

Current strategies to cryopreserve cells and organs involve bathing them with large amounts of dimethyl sulfoxide, a toxic chemical that messes up ice formation but stresses the cells, decreasing their odds for survival.

Nature, however, has found a way to keep organisms alive under extreme cold conditions: antifreeze proteins. Fish, insects and other cold-blooded organisms have evolved potent antifreeze glycoproteins that bind to ice crystallites and halt them from growing and damaging cells.

The growing area of cell-based therapeutics demands the development of potent inhibitors of ice recrystallization that can compete in activity with natural antifreeze glycoproteins but do not have the cost and toxicity of dimethyl sulfoxide. This demand has propelled the synthesis of polymers that mimic the action of antifreeze glycoproteins. But the most potent synthetic ice recrystallization inhibitor found to date, polyvinyl alcohol (PVA), is orders of magnitude less potent than natural glycoproteins.

"Efforts to identify stronger inhibitors for ice growth seem to have stalled, as there is not yet a molecular understanding of the factors that limits the ice recrystallization inhibition efficiency of polymers," Molinero says.

A hidden polymer design variable

How do molecules prevent ice crystals from getting bigger? Molecules that bind strongly to ice pin its surface--like stones on a pillow--making the ice front develop a curved surface around the molecules. This curvature destabilizes the ice crystal, halting its growth. Molecules that stay bound to ice for times longer than the time it takes to grow ice crystals succeed in preventing further growth and recrystallization.

Molinero and Naullage used large-scale molecular simulations to elucidate the molecular underpinnings of how flexibility, length and functionalization of polymers control their binding to ice and their efficiency to prevent ice growth. Their study shows that the bound time of the molecules at the ice surface is controlled by the strength of their ice binding coupled with the length of the polymer and how fast they propagate on the ice surface.

"We found that the efficiency of flexible polymers in halting ice growth is limited by the slow propagation of their binding to ice," Molinero says.

The study dissects the various factors that control the binding of flexible polymers to ice and that account for the gap in potency of PVA and natural antifreeze glycoproteins. In a nutshell, each block of antifreeze glycoproteins binds more strongly to ice than PVA does, and are also favored by their secondary molecular structure that segregates the binding and non-binding blocks to allow them to attach faster to ice to stop its growth.

"To our knowledge, this work is first to identity the time of propagation of binding as a key variable in the design of efficient ice-binding flexible polymers," Naullage says. "Our study sets the stage for the de novo design of flexible polymers that can meet or even surpass the efficiency of antifreeze glycoproteins and make an impact in biomedical research."

Numerous questions remain unanswered as to how the planet's species will respond to climate change. A new paper in the journal Frontiers in Physiology suggests that at least one species of marsupial "mice" may struggle to adapt to a warming world.

The study found that changes in ambient temperatures experienced during the development and growth of yellow-footed antechinus (Antechinus flavipes) can influence their behavioral and physiological traits.

"This has important implications in terms of how this species will respond to changes in the climate," said lead author Dr. Clare Stawski, associate professor at Norwegian University of Science and Technology. "Individuals raised in warm conditions appear to have less phenotypic flexibility, suggesting that they may not be able to respond effectively to prolonged increases in temperature."

Phenotypic flexibility refers to the ability of an organism to adjust to a new type of environmental stress. In this case, Stawski and colleague Dr. Fritz Geiser, a professor at the University of New England in Australia, wanted to see how antechinus might respond to temperature swings for varying time periods.

The experiment involved 19 juvenile antechinus, which were split into two groups and subjected to different temperature regimes ranging from 16.7 degrees Celsius to 24.7 degrees Celsius. Infrared sensors attached to individual cage lids measured their activity and custom-made data loggers recorded their behavior.

Once the miniature marsupials reached adult age, the scientists measured metabolic rates, body mass and other physiological parameters across another set of experiments. These included putting them into temperature-controlled chambers where they experienced further variations in temperatures.

Overall, the yellow-footed antechinus were more active with lower metabolic rates at warmer temperatures. This is typical for many mammals shifting from winter to summer. However, the results from the experiments also suggested that while individuals can withstand short periods of warmer temperatures, they don't have a particularly effective strategy to endure prolonged heat waves.

That's not good news, considering that Australia's national science agency, the Commonwealth Scientific and Industrial Research Organisation (CSIRO), projects "very high confidence" that hot days will become more frequent and hotter in the future.

Australia is home to at least ten species of insect-munching antechinus. While they superficially resemble rodents, these marsupial carnivores behave much differently. For example, their love lives: The animals engage in a short but frenzied period of mating, after which the males die from stress-induced immune system breakdown. Another difference is that antechinus can enter a state of decreased physiological activity, or torpor, in response to colder temperatures or other environmental factors.

Stawski noted that the results of the current study can likely be used to make broad assumptions about all antechinus species, as they share a similar ecology in terms of reproduction and habitats.

"Further, I do think our results could also be applicable to other small marsupials that employ daily torpor," she said.

In previous studies, Stawski, Geiser and their colleagues have investigated how small marsupials might respond to wildfires. They found that torpor can be a very effective means for surviving a wildfire, both during a fire if the animals are in a safe refuge and after the fire when resources are limited.

However, the recent fires that have enveloped vast regions of Australia is another story entirely. Some estimates claim the fires have killed more than one billion animals.

"Torpor during a fire is only beneficial if the refuge protects the torpid animal," Stawski noted. "It is likely that many torpid animals perished during the current wildfires in Australia due to their severity. Further, as these wildfires are occurring during summer and heatwaves, many animals would be unable to effectively employ torpor due to the high temperatures."

The tropical region of South America is one of the world's hot spots when it comes to animal diversity. The region's extinct fauna is unique, as documented by fossils of giant rodents and crocodylians -including crocodiles, alligators, caimans and gavials - that inhabited what is today a desert area in Venezuela. Five to ten million years ago, this was a humid swampy region teeming with life. One of its inhabitants was Stupendemys geographicus, a turtle species first described in the mid-1970s.

Giant turtle 100 times heavier than its closest relative

Researchers of the University of Zurich (UZH) and fellow researchers from Colombia, Venezuela, and Brazil have now reported exceptional specimens of the extinct turtle recently found in new locations across Venezuela and Colombia. "The carapace of some Stupendemys individuals reached almost three meters, making it one of the largest, if not the largest turtle that ever existed," says Marcelo Sánchez, director of the Paleontological Institute and Museum of UZH and head of the study. The turtle had an estimated body mass of 1,145 kg - almost one hundred times that of its closest living relative, the big-headed Amazon river turtle.

Males carried horns on their carapace

In some individuals, the complete carapace showed a peculiar and unexpected feature: horns. "The two shell types indicate that two sexes of Stupendemys existed - males with horned shells, and females with hornless shells," concludes Sánchez. According to the paleobiologist, this is the first time that sexual dimorphism in the form of horned shells has been reported for any of the side-necked turtles, one of the two major groups of turtles world-wide.

Despite its tremendous size, the turtle had natural enemies. In many areas, the occurrence of Stupendemys coincides with Purussaurus, the largest caimans. This was most likely a predator of the giant turtle, given not only its size and dietary preferences, but also as inferred by bite marks and punctured bones in fossil carapaces of Stupendemys.

Turtle phylogeny thoroughly revised

Since the scientists also discovered jaws and other skeleton parts of Stupendemys, they were able to thoroughly revise the evolutionary relationships of this species within the turtle tree of life. "Based on studies of the turtle anatomy, we now know that some living turtles from the Amazon region are the closest living relatives," says Sánchez. Furthermore, the new discoveries and the investigation of existing fossils from Brazil, Colombia and Venezuela indicate a much wider geographic distribution of Stupendemys than previously assumed. The animal lived across the whole of the northern part of South America.

Scientists have identified a metabolic biomarker that could help track the progression of arrhythmogenic cardiomyopathy (AC) - an inherited heart condition that can kill swiftly and without warning - in a study of heart tissue and plasma from patients with AC. Even in patients with a family history of AC, sudden cardiac death is often the first detectable symptom of the disease. There are currently no clinical assessments specific for AC, and patients can remain outwardly healthy for up to 40 years. Now, building on prior work that indicated metabolic abnormalities in the heart muscle of AC patients, Jiang-Ping Song and colleagues have found that high levels of ketone bodies in the plasma of AC patients could serve as a reliable predictor of AC progression. The researchers compared heart tissue from a cohort of 13 AC patients with heart tissue from 13 healthy donors and found increased expression of enzymes involved in ketone metabolism in the AC patients' hearts. They also compared plasma samples from AC patients, healthy volunteers, and patients diagnosed with other cardiopulmonary diseases, and found elevated levels of ketone bodies - especially β-hydroxybutyrate - in the AC patient samples. Using both a mouse model of AC and cardiomyocytes derived from stem cells generated from AC patients, the researchers found further evidence for ketone-producing metabolic pathways as a hallmark of AC. In a final validation step, the researchers compared plasma from a cohort of 65 AC patients, 94 of their relatives, and 62 healthy volunteers, and found elevated β-hydroxybutyrate levels in the AC patients and some of their relatives. The findings suggest that β-hydroxybutyrate could serve as a reliable predictor of AC progression in those suspected to be at risk of the disease.

Climate Change to Create Farmland in the North, But at Environmental Costs, Study Reveals

In a warming world, Canada's north may become our breadbasket of the future - but this new "farming frontier" also poses environmental threats from increased carbon emissions to degraded water quality, according to the first-ever study involving University of Guelph researchers

The research team modelled prospects for growing major food crops in potential new farmland that may come available as climate change alters growing seasons worldwide.

"Areas currently not suitable for agriculture are likely to become suitable in the next 50 to 100 years," said Krishna Bahadur KC, an adjunct professor and research scientist with the Department of Geography, Environment and Geomatics (GEG).

The researchers found Earth's agricultural landmass could increase by almost one-third, including vast new farming prospects in Canada and Russia's north, but not without major environmental impacts such as soil carbon emissions, loss of biodiversity and declines in water quality.

"As current lands become less suitable, there's going to be pressure to develop new frontiers and that's going to come with a host of major environmental consequences like releasing unprecedented amounts of carbon in the atmosphere, which then fuels additional climate change," said Lee Hannah, senior climate change scientist, Conservation International and lead author of the paper.

Published recently in PLOS One, the study combined projections for temperature and precipitation from 17 global climate models with agricultural models that predict suitability for growing 12 globally important food crops.

"We used climate change projections and crop science data to see what we might be able to grow in these regions," said Krishna.

Areas that may become newly suitable for one crop or more crops - so called climate-driven agricultural frontiers - cover an area equivalent to more than 30 per cent of the landmass already being farmed worldwide.

Globally, the study found prospective croplands are expected to be most extensive in northern boreal regions. More than half of that landmass lies in Canada (4.2 million square kilometres) and Russia (4.3 million square kilometres).

In Canada, four crops - wheat, potatoes, corn and soy - are cold-tolerant enough to grow in more northerly regions under climate change, according to the study.

With longer growing seasons, wheat and potatoes might be suitable for cultivation across the northern reaches of most provinces and much of the Northwest Territories and Yukon. Corn and soy could also be grown farther northward, although less extensively.

Growing food in new areas may promote economic development, reducing poverty and food insecurity in Canada's North, said the researchers.

At the same time, the team calls for policy-makers to balance the need for more food with the potential environmental impacts of more widespread farming.

"The tradeoffs between environmental concerns and food production may be very significant," said co-author Prof. Evan Fraser, director of U of G's Arrell Food Institute. "We need to think carefully about environmental sustainability. And any thought of developing agriculture to take advantage of longer growing seasons due to climate change had to be mindful of the role of Indigenous governance in these areas. Many of the areas our model suggest may become more suitable for farming are the home of a great many Indigenous communities."

If all the globe's potential agricultural frontier became farmland, about 177 gigatonnes of carbon would be released from its soils - the equivalent of more than a century's worth of CO2 emissions currently produced by the United States, said Krishna.

More intensive farming would also threaten biodiversity hot spots in Central America and the northern Andes, and potentially degrade water quality, he added.

The world will need to produce an estimated 70 per cent more food by 2050 to sustain a human population of about 9 billion. Population estimates for the end of the century range from about 7 billion people to more than 16 billion.

The researchers recommend promoting farming practices that conserve soil carbon, such as leaving northern peat soils intact. Other options include shifting to more plant-based diets, reducing food waste, adopting yield-boosting technologies and using existing croplands more intensively - although none of those strategies would provide as much food as cultivating frontier farmland, said Krishna.

"We need food, but we don't want environmental impacts. We need to find a way to balance."

Glioblastomas are relentless, hard-to-treat, and often lethal brain tumors. Yale scientists have enlisted a most unlikely ally in efforts to treat this form of cancer -- elements of the Ebola virus.

"The irony is that one of the world's deadliest viruses may be useful in treating one of the deadliest of brain cancers," said Yale's Anthony van den Pol, professor of neurosurgery, who describes the Yale efforts Feb. 12 in the Journal of Virology.

The approach takes advantage of a weakness in most cancer tumors and also of an Ebola defense against the immune system response to pathogens.

Unlike normal cells, a large percentage of cancer cells lack the ability to generate an innate immune response against invaders such as viruses. This has led cancer researchers to explore the use of viruses to combat a variety of cancers.

Using viruses carries an obvious risk -- they can introduce potentially dangerous infections. To get around this problem, scientists, including van den Pol, have experimented with creating or testing chimeric viruses, or a combination of genes from multiple viruses. They have the ability to target cancer cells without harming patients.

One of the seven genes of the Ebola virus that helps it avoid an immune system response also contributes to its lethality. This intrigued van den Pol.

He and the study's first author, Xue Zhang, also of Yale, used a chimeric virus containing one of gene from the Ebola virus -- a glycoprotein with a mucin-line domain (MLD). In wild-type Ebola virus, the MLD plays a role in hiding Ebola from the immune system. They injected this chimeric virus into the brains of mice with glioblastoma -- and found that the MLD helped selectively target and kill deadly glioblastoma brain tumors.

(The team worked with the MLD glycoprotein, not with the full Ebola virus.)

Van den Pol said MLD's beneficial effect appears to be that it protects normal cells from infection -- but not cancer cells, which lack the ability to mount an immune response to pathogens.

A key factor may be that the virus with the glycoprotein MLD replicates less rapidly, potentially making it safer than viruses without the MLD part of the glycoprotein, he said.

In theory, such a virus might be used in conjunction with surgery to eliminate glioblastoma tumors and help prevent a recurrence of cancer, he said.

ANN ARBOR--Parents often put their own relationship on the back burner to concentrate on their children, but a new study shows that when spouses love each other, children stay in school longer and marry later in life.

Research about how the affection between parents shapes their children's long-term life outcomes is rare because the data demands are high. This study uses unique data from families in Nepal to provide new evidence. The study, co-authored by researchers at the University of Michigan and McGill University in Quebec, was published in the journal Demography.

"In this study, we saw that parents' emotional connection to each other affects child rearing so much that it shapes their children's future," said co-author and U-M Institute for Social Research researcher William Axinn. "The fact that we found these kinds of things in Nepal moves us step closer to evidence that these things are universal."

The study uses data from the Chitwan Valley Family Study in Nepal. The survey launched in 1995, and collected information from 151 neighborhoods in the Western Chitwan Valley. Married couples were interviewed simultaneously but separately, and were asked to assess the level of affection they had for their partner. The spouses answered "How much do you love your (husband/wife)? Very much, some, a little, or not at all?"

The researchers then followed the children of these parents for 12 years to document their education and marital behaviors. The researchers found that the children of parents who reported they loved each other either "some" or "very much" stayed in school longer and married later.

"Family isn't just another institution. It's not like a school or employer. It is this place where we also have emotions and feelings," said lead author Sarah Brauner-Otto, director of the Centre on Population Dynamics at McGill University. "Demonstrating and providing evidence that love, this emotional component of family, also has this long impact on children's lives is really important for understanding the depth of family influence on children."

Nepal provides an important backdrop to study how familial relationships shape children's lives, according to Axinn. Historically, in Nepal, parents arranged their children's marriage, and divorce was rare. Since the 1970s, that has been changing, with more couples marrying for love, and divorce still rare, but becoming more common.

Education has also become more widespread since the 1970s. In Nepal, children begin attending school at age 5, and complete secondary school after grade 10, when they can take an exam to earn their "School-Leaving Certificate." Fewer than 3% of ever-married women aged 15-49 had earned an SLC in 1996, while nearly a quarter of women earned an SLC in 2016. Thirty-one percent of men earned SLCs in 2011. By 2016, 36.8% of men had.

The researchers say that their next important question will be to identify why parental love impacts children in this way. The researchers speculate that when parents love each other, they tend to invest more in their children, leading to children remaining in education longer. The children's home environments may also be happier when parents report loving each other, so the children may be less likely to escape into their own marriages. Children may also view their parents as role models, and take longer to seek similar marriages.

These findings still stood after researchers considered other factors that shape a married couple's relationship and their children's transition to adulthood. These include caste-ethnicity; access to schools; whether the parents had an arranged marriage; the childbearing of the parents; and whether the parents had experience living outside their own families, possibly being influenced by Western ideas of education and courtship.

"The result that these measures of love have independent consequences is also important," Axinn said. "Love is not irrelevant; variations in parental love do have a consequence."

HOUSTON -- (Feb. 12, 2020) -- U.S. and Australian researchers have found a potential tool for identifying "super corals" that can tolerate a limited amount of climate change.

"We may be able to use algae team characteristics to identify coral colonies to focus on for conservation or restoration,'" said veteran reef researcher Adrienne Correa, a Rice University marine biologist and co-author of a newly published study in the journal Global Change Biology. "It's not sufficient -- if we don't limit carbon dioxide emissions, it's not going to be enough to save coral reefs -- but it's exciting."

In the study, marine biologists from the Australian Institute of Marine Science (AIMS) gathered corals from the Great Barrier Reef and used separately controlled tanks to compare how well they responded to rising ocean temperatures, increased acidity and exposure to bacterial pests.

A look at the symbiotic algae inside the corals revealed an interesting dynamic: Corals with more similar groups of algae survived better under stress.

"What's unique about this project is that we looked at the whole community of symbiotic algae in relation to coral stress tolerance in these colonies," said Rice graduate student and study lead co-author Lauren Howe-Kerr.

"It's like looking at all the players on a sports team together as you try to predict how their next season might go," said Correa, Howe-Kerr's Ph.D. advisor and an assistant professor of biosciences at Rice. "Individual talent is important, but so is the team that talent works with."

Howe-Kerr began her research during a 2016 undergraduate study abroad semester at AIMS in Townsville, Queensland. While others examined the corals' evolution of resistance to the experimental stresses, she focused on their single-celled partners, a kind of algae called dinoflagellates.

In exchange for a protected life inside corals, dinoflagellates help feed their hosts by converting sunlight into food. They also impart the vibrant colors that are seen in reefs. A single coral colony can be home to multiple species of dinoflagellates. And while they may look identical under a microscope, the differences between groups are detectable by DNA analysis.

In the Global Change Biology study, Howe-Kerr, Correa and co-authors, including Bénédicte Bachelot of Rice and Line Bay of AIMS, showed how symbiont community diversity might be used to predict coral stress response.

"In the past, a lot of studies have looked for 'savior' symbionts, specific types that provide the coral colony with extra stress tolerance," Correa said. "Lauren had the great idea to look at how the microbiome, or this symbiotic community of dinoflagellates, holistically related to stress response."

Correa said the study did not directly test how well the symbionts worked together as a team.

"That's a next step, but for this study we just know the roster of players, or species, on each team," she said. "We know that the team rosters for poorly performing corals contain more variable symbiont communities than the rosters for the best performers. And that tells us that the identity of specific symbionts, or players, isn't the only important factor."

In the study, corals were subjected to 10-day stress tests in flow-through seawater tanks at the AIMS National Sea Simulator. In independently controlled tanks, fragments of each of the colonies were exposed to the kinds of stress corals undergo as a result of human-caused climate change. In one set of tanks, temperatures gradually increased from 27 to 30 degrees Celsius (80.6 to 86 degrees Fahrenheit). In another, dissolved carbon dioxide was added to the seawater to simulate ocean acidification. The pH in these tanks dropped gradually from 8.0 to 7.8 during the 10-day test. A third group of tanks simulated the stress caused by bacterial pathogens on reefs. Corals in a fourth set of tanks were simultaneously exposed to all three stresses, and the experiment also included a control, a fifth group of tanks where corals were stress-free.

Howe-Kerr compared the communal structures of dinoflagellate symbionts in two groups of corals: the four colonies that responded best to the stresses and the four that responded worst.

"In the best-performing corals, we saw a more constrained community that changed very little, no matter which stress they experienced." she said. "In contrast, the colonies that performed poorly under stress had community characteristics that varied. You could even see this in the controls, which hadn't experienced stress."

The results suggest that the symbiont communities in the best performers are working well together and with their coral host, both under good conditions and under stress. In the worst performers, the diversity of patterns instead suggests that some corals aren't as good at controlling their microbiome, and under stress, their dinoflagellate teams can go haywire.

Correa said the results suggest that the coral symbiont microbiome is subject to the "Anna Karenina principle," a scientific paradigm described by the first sentence of Leo Tolstoy's 1878 novel "Anna Karenina": "Happy families are all alike; every unhappy family is unhappy in its own way."

Tolstoy was no scientist, but his insight into human family dynamics was so keen that scientists have adapted it as a general concept for success and failure in complex systems. In complex undertakings that depend upon many factors, and where each factor is critical for success, the principle means that a single deficiency, in any factor, can spell failure. But because there are so many ways to fail, no two failures play out the same. Successes, in contrast, tend to look the same, because each is a case with no critical failure.

The principle has been applied in statistics, economics, medicine, ecology and more, but Correa said this is the first application to the study of coral-dinoflagellate microbiomes.

Howe-Kerr said she is looking forward to seeing whether the results from the tank-based experiments also apply to corals experiencing stress on reefs.

"Over the past two years, we've been involved in a sampling effort in Mo'orea, French Polynesia, where we've tagged individual coral colonies all around the island," she said. "When I was there last summer, there was a massive bleaching event. Almost all of the colonies that we had already sampled in previous years bleached."

Coral bleaching occurs when corals expel their dinoflagellate partners in response to extreme stress. Coral bleaching has become increasingly common as ocean temperatures have increased over the past 40 years. Some corals survive bleaching, but many do not.

"Because of the work we've already done, there's an opportunity to test the tank-based findings on a large-scale around the island," Howe-Kerr said. "We want to see if it's possible to predict which corals ultimately survived the bleaching event based upon the prior makeup of their symbiont community."

One of the central questions in neuroscience is clarifying where in the brain consciousness, which is the ability to experience internal and external sensations, arises. On February 12 in the journal Neuron, researchers report that a specific area in the brain, the central lateral thalamus, appears to play a key role. In monkeys under anesthesia, stimulating this area was enough to wake the animals and elicit normal waking behaviors.

Previous studies, including EEG and fMRI studies in humans, had suggested that certain areas of the brain, including the parietal cortex and the thalamus, appear to be involved in consciousness. "We decided to go beyond the classical approach of recording from one area at a time," says senior author Yuri Saalmann, an assistant professor at the University of Wisconsin, Madison. "We recorded from multiple areas at the same time to see how the entire network behaves."

The investigators used macaques as their animal model. By studying awake, sleeping, and anesthetized animals, they were able to narrow down the region of the brain involved in consciousness to a much more specific area than other studies have done. They were also able to rule out some areas that had been proposed in previous neurocorrelative studies of consciousness. They ultimately focused on the central lateral thalamus, which is found deep in the forebrain.

Once the researchers pinpointed this area, they tested what happened when the central lateral thalamus was activated while the animals were under anesthesia, stimulating the region with a frequency of 50 Hz. "We found that when we stimulated this tiny little brain area, we could wake the animals up and reinstate all the neural activity that you'd normally see in the cortex during wakefulness," Saalmann says. "They acted just as they would if they were awake. When we switched off the stimulation, the animals went straight back to being unconscious."

One test of wakefulness was their neural responses to oddball auditory stimulation--a series of beeps interspersed with other random sounds. The animals responded in the same way that awake animals would respond.

"Our electrodes have a very different design," Saalmann says. "They are much more tailored to the shape of the structure in the brain we want to stimulate. They also more closely mimic the electrical activity that's seen in a healthy, normal system."

"The overriding motivation of this research is to help people with disorders of consciousness to live better lives," says first author Michelle Redinbaugh, a graduate student in the Department of Psychology at the University of Wisconsin, Madison. "We have to start by understanding the minimum mechanism that is necessary or sufficient for consciousness, so that the correct part of the brain can be targeted clinically."

"There are many exciting implications for this work," she says. "It's possible we may be able to use these kinds of deep-brain stimulating electrodes to bring people out of comas. Our findings may also be useful for developing new ways to monitor patients under clinical anesthesia, to make sure they are safely unconscious."

More than half of all air-quality-related early deaths in the United States are a result of emissions originating outside of the state in which those deaths occur, MIT researchers report in the journal Nature.

The study focuses on the years between 2005 and 2018 and tracks combustion emissions of various polluting compounds from various sectors, looking at every state in the contiguous United States, from season to season and year to year.

In general, the researchers find that when air pollution is generated in one state, half of that pollution is lofted into the air and carried by winds across state boundaries, to affect the health quality of out-of-state residents and increase their risk of early death.

Electric power generation is the greatest contributor to out-of-state pollution-related deaths, the findings suggest. In 2005, for example, deaths caused by sulfur dioxide emitted by power plant smokestacks occurred in another state in more than 75 percent of cases.

Encouragingly, the researchers found that since 2005, early deaths associated with air pollution have gone down significantly. They documented a decrease of 30 percent in 2018 compared to 2005, equivalent to about 30,000 avoided early deaths, or people who did not die early as a result of pollution. In addition, the fraction of deaths that occur due to emissions in other states is falling -- from 53 percent in 2005 to 41 percent in 2018.

Perhaps surprisingly, this reduction in cross-state pollution also appears to be related to electric power generation: In recent years, regulations such as the Environmental Protection Agency's Clean Air Act and other changes have helped to significantly curb emissions from this sector across the country.

The researchers caution, however, that today, emissions from other sectors are increasingly contributing to harmful cross-state pollution.

"Regulators in the U.S. have done a pretty good job of hitting the most important thing first, which is power generation, by reducing sulfur dioxide emissions drastically, and there's been a huge improvement, as we see in the results," says study leader Steven Barrett, an associate professor of aeronautics and astronautics at MIT. "Now it's looking like other emissions sectors are becoming important. To make further progress, we should start focusing on road transportation and commercial and residential emissions."

Barrett's coauthors on the paper are Sebastian Eastham, a research scientist at MIT; Irene Dedoussi, formerly an MIT graduate student and now an assistant professor at Delft University of Technology; and Erwan Monier, formerly an MIT research scientist and now an assistant professor at the University of California at Davis. The research was a collaboration between MIT's Laboratory for Aviation and the Environment and the MIT Joint Program on the Science and Policy of Global Change.

Death and the matrix

Scientists have long known that pollution observes no boundaries, one of the prime examples being acid rain.

"It's been known in Europe for over 30 years that power stations in England would create acid rain that would affect vegetation in Norway, but there's not been a systematic way to capture how that translates to human health effects," Barrett says.

In the case of the United States, tracking how pollution from one state affects another state has historically been tricky and computationally difficult, Barrett says. For each of the 48 contiguous states, researchers would have to track emissions to and from the rest of the 47 states.

"But now there are modern computational tools that enable you to do these assessments in a much more efficient way," Barrett says. "That wasn't really possible before."

He and his colleagues developed such tools, drawing on fundamental work by Daven Henze at the University of Colorado at Boulder, to track how every state in the contiguous U.S. affects pollution and health outcomes in every other state. They looked at multiple species of pollutants, such as sulfur dioxide, ozone, and fine particulates, from various emissions sectors, including electric power generation, road transportation, marine, rail, and aviation, and commercial and residential sources, at intervals of every hour of the year.

They first obtained emissions data from each of seven sectors for the years 2005, 2011, and 2018. They then used the GEOS-Chem atmospheric chemistry transport model to track where these emissions ended up, from season to season and year to year, based on wind patterns and a pollutant's chemical reactions to the atmosphere. Finally, they used an epidemiologically derived model to relate a population's pollutant exposure and risk of early death.

"We have this multidimensional matrix that characterizes the impact of a state's emissions of a given economic sector of a given pollutant at a given time, on any other state's health outcomes," Barrett says. "We can figure out, for example, how much NOx emissions from road transportation in Arizona in July affects human health in Texas, and we can do those calculations instantly."

Importing pollution

The researchers also found that emissions traveling out of state could affect the health of residents beyond immediate, neighboring states.

"It's not necessarily just the adjacent state, but states over 1,000 miles away that can be affected," Barrett says. "Different kinds of emissions have a different kind of range."

For example, electric power generation has the greatest range, as power plants can loft pollutants far into the atmosphere, allowing them to travel over long distances. In contrast, commercial and residential sectors generally emit pollutants that chemically do not last as long in the atmosphere.

"The story is different for each pollutant," Barrett says.

In general, the researchers found that out-of-state air pollution was associated with more than half of all pollution-related early deaths in the U.S. from 2005 to 2018.

In terms of the impact on individual states, the team found that many of the northern Midwest states such as Wyoming and North Dakota are "net exporters" of pollution-related health impacts, partly because the populations there are relatively low and the emissions these states generate are carried away by winds to other states. Those states that "import" health impacts tend to lie along the East Coast, in the path of the U.S. winds that sweep eastward.

New York in particular is what the researchers call "the biggest importer of air pollution deaths"; 60 percent of air pollution-related early deaths are from out-of-state emissions.

"There's a big archive of data we've created from this project," Barrett says. "We think there are a lot of things that policymakers can dig into, to chart a path to saving the most lives."

Researchers at the University of Chicago have developed the first truly accurate mouse model of celiac disease. The animals have the same genetic and immune system characteristics as humans who develop celiac after eating gluten. This provides a vital research tool for developing and testing new treatments for the disease.

"Based on our understanding of the human disease, we were able to retro-engineer a mouse model of celiac disease," said Bana Jabri, MD, PhD, Director of Research at the University of Chicago Medicine Celiac Disease Center and senior author of the new study, published this week in Nature. "It's the first model where the mouse develops damage to the small intestine just by eating gluten, which can later reverse itself on a gluten-free diet."

Celiac disease is an autoimmune disorder that affects an estimated 1% of people worldwide. It causes gastrointestinal symptoms and damage to the lining of the small intestine when someone eats gluten, a protein found in grains such as wheat, barley and rye.

There is no cure, and the only effective treatment is a gluten-free diet, which can be difficult to maintain. Even the most careful celiac patients can accidentally ingest gluten through unknown ingredients in processed food or cross-contamination from foods containing gluten that are prepared nearby or with the same cooking equipment.

Even while maintaining a strict gluten-free diet, 40% of celiac disease patients still show signs of inflammation and villous atrophy, or damage to the villi, the small, finger-like protrusions in the small intestine that help absorb nutrients. Therefore, treatments that can reverse or prevent the disease are greatly needed to improve quality of life for people with celiac.

A complex interplay of contributing factors

Scientists do not know the exact cause of celiac disease, but researchers have identified several genetic, immune system, and environmental components that work together to trigger the disease. People with celiac have one of two genetic variants, HLA-DQ2 and HLA-DQ8, that are part of a group of genes that help the immune system recognize foreign antigens and mount an immune response. However, possessing one these variants is not sufficient to develop the disease alone.

Based on studies in celiac disease patients, Jabri and her colleagues have proposed that signs of tissue distress associated with high levels of an inflammatory protein called IL-15 in the lining of the small intestine were required to cause villous atrophy, the hallmark of the disease.

Certain environmental factors may come into play as well. In 2017, for example, Jabri and her team discovered that a common and relatively harmless virus can cause changes to the immune system that set the stage for celiac. All of these factors work together to trigger an autoimmune response when someone ingests gluten that causes villous atrophy.

All the puzzle pieces fall into place

For more than 20 years, researchers have attempted to develop a mouse model for celiac that reflects these conditions. However, none of these models resulted in mice with one of the HLA gene variants that also developed villous atrophy in response to gluten.

"In celiac, the main feature of disease is tissue destruction of the small intestinal lining," said Valerie Abadie, PhD, a research assistant professor at UChicago and lead author of the study. "This new HLA-DQ8 mouse model is unique because it's the only one that actually develops villous atrophy when the animal does eat gluten. In addition, once the mice are placed on a gluten-free diet, their small intestine can recover and heal, just as in humans with celiac disease."

Jabri said that all of these elements must be present in a research model to truly represent the conditions that cause disease in humans.

"It's like a puzzle where different pieces need to come together for everything to fall into place," Jabri said. "If you have a model where only one piece of the puzzle causes the disease because it's in a laboratory setting, then you cannot test how to block or interfere with the other components. You need to have a setup where you have the entire complex interplay that takes place for the development of celiac disease."

The new mouse model provides a vital tool for developing new treatments to reverse celiac once it has developed, or prevent it from developing in people at risk for the disease. Researchers will be able to identify new targets for drugs and then test them in a model that faithfully represents the condition in humans.

"This wouldn't be possible without first conducting human studies to understand the nature of the disease," Jabri said. "Now, using the mouse model, we can interrogate more and apply what we learned back into the human system. The integration of those two approaches is very important."

In the dermis skin layer, the same bacteria are found across age and gender. This has been shown by researchers from the University of Copenhagen in a new study which has studied skin samples from knees and hips. The researchers hope it is a step in the direction of a better understanding of why skin disorders occur.

The bacterial microbiome on the skin has been compared to a fingerprint: Unique to each person. This does indeed apply to the epidermis, the outer layer of skin. But further down, in the layer of skin called dermis, we are all alike and have the same bacteria.

This is shown by researchers from the University of Copenhagen in a new study, published in the scientific journal mBio.

"We found that the microbiome in epidermis is unique. It is very different and depending on age and gender. On the other hand, the microbiome in dermis is the same - regardless of age and gender. This has not been shown before," says co-author Lene Bay, Postdoc at the Department of Immunology and Microbiology, University of Copenhagen.

The researchers have studied skin samples from knees and hips. They have received the samples from Danish patients who were to have knee surgery. All the operations were so-called primary operations, that is, the patients did not have an infection on beforehand and were healthy.

Importance for Skin Disorders

The results have an impact on our understanding of the skin and its bacteria. According to the researchers, this knowledge is important if we are to become better at treating skin disorders such as childhood eczema and psoriasis and understand why they occur.

"It is important that we drop the assumption that we are all different, and that the microbiome of the skin does not matter very much. We do know that bacteria play a major role in skin disorders. Therefore, we need to understand the bacteria and the skin in its three dimensions," says co-author Thomas Bjarnsholt, Professor at the Department of Immunology and Microbiology, University of Copenhagen.

"Especially in connection with skin disorders, you see that the healthy skin balance disappears and that there is a build-up of some dominant bacterial species. Hopefully, this knowledge will help us to understand for example how eczema occurs and which irregularities are taking place in the skin," says Thomas Bjarnsholt.

Bacteria Pushed Down

The understanding of the dermis microbiome may also be important to understand how, for example, acute wounds, infections and surgical wounds occur. There is always a risk of infection in connection with surgery. For knee and hip surgery, the risk is one to two percent.

"It is not a huge problem, but there are many knee and hip operations on a yearly basis, and we will see more and more in the future. That is why it will represent a growing problem. We believe that the dermis' microbiome has a bearing on the risk of infection after surgery," says Lene Bay.

"When you cut through the skin during surgery, you may be pushing some of these bacteria even further down. And the underlying bacteria are not cleansed with surgical ethanol like the bacteria on epidermis. Which significance that may have and whether it may be the cause of post-surgery infections is one of the things that we need to study more closely," says Lene Bay.

The researchers' next step will be to study other skin areas. Knees and hips are dry skin areas. Therefore, researchers would also like to study oily and moist skin habitat, for example respectively the upper back and the armpit. In the long term, the researchers would also like to study skin samples from diseased patients in order to be able to compare the microbiome in dermis from healthy and diseased persons.

Parabens are used as preservatives in cosmetics. If pregnant women use cosmetics containing parabens that remain on the skin for protracted periods, this may have consequences for their child's subsequent weight development. This is demonstrated in a study published in the journal Nature Communications by researchers from the Helmholtz Centre for Environmental Research (UFZ) in collaboration with colleagues from Leipzig University, Charité University Hospital in Berlin and the Berlin Institute of Health (BIH). Based on data from the LINA mother-child study, they were further able to identify epigenetic modifications that are triggered by parabens and interfere with the natural regulation of satiety in the brain.

Methylparaben, propylparaben, butylparaben - these and similar are the names of parabens commonly used as preservatives. Substances that are used in creams and body lotions to combat microbes can have an undesirably side-effect, however. "If pregnant women absorb parabens through the skin, this can lead to overweight in their children", says UFZ environmental immunologist Dr Tobias Polte. The starting point for the investigations was the LINA mother-child cohort study, a long-term study conducted by the UFZ to examine the significance of environmental factors in sensitive periods of childhood development for the later occurrence of allergies and respiratory diseases or overweight. "We initially wanted to find out whether the parabens detected in urine from expectant mothers from the mother-child cohort had an impact on the development of their children's weight", explains former UFZ researcher Prof. Irina Lehmann, currently at the Berlin Institute of Health (BIH) and at Charité - Berlin University Hospital. "In doing so, we discovered a positive correlation between the concentrations of butylparaben in the mothers' urine and a higher body-mass index of their children - particularly of the daughters - until their eighth birthday."

In order to find out where the butylparabens in the pregnant women's urine came from in the first place, the researchers combed through the questionnaires completed by the participants in the LINA study for details of the cosmetics used during pregnancy. "Using the ToxFox app developed by BUND enabled us to easily and quickly check whether parabens were among the ingredients of the respective cosmetics products", Polte explains. "And high concentrations of parabens in the mothers' urine were indeed associated with the use of cosmetics containing parabens - particularly those that remained on the skin for a protracted period of time, such as creams or body lotions."

But how does the use of creams containing parabens by expectant mothers tie in with the child's future overweight? To track down the underlying mechanisms, the team of researchers firstly used cell cultures to examine whether fat cells themselves react to high concentrations of butylparaben. "Butylparaben did not bring about an increase in the size of the fat cells, nor did the fat cells store more fat than otherwise", Lehmann reports. "It was evident that the differentiation of fat cells was not impacted by the parabens." Something else had to be behind the children's weight gain. In collaboration with colleagues from the Medical Faculty at Leipzig University, the researchers used a mouse model to simulate exposure to parabens during pregnancy. In this model, mice absorbed butylparabens through the skin. "Just as in the LINA study, the female offspring here also demonstrated increased weight gain", says Polte. "And they ate significantly more than the offspring of mice from the control group." Consequently, the researchers suspected that parabens might exert an influence on how hunger is regulated in the brain, and performed a closer examination of key genes in the hypothalamus of the mouse offspring.

It became apparent that a gene by the name of proopiomelanocortin (POMC) that is decisive in controlling the feeling of hunger was down-regulated in the brains of the young mice. Further investigations at a genetic level revealed that an epigenetic modification was responsible for this by preventing the corresponding POMC gene from being read. "The influence of parabens during gestation obviously gives rise to epigenetic modifications in the offspring that permanently disrupt the regulation of the natural feeling of satiety. This means that they have a higher food intake", Polte explains. Therefore, parabens seem to constitute as a risk factor during pregnancy for the occurrence of overweight. However, also other factors play an important role in weight gain, such as a hypercaloric diet and lack of exercise.

So far, the researchers have not been able to come to any conclusions on how stable the epigenetic modifications are or whether they can be passed on to the next generation. However, they are already able to make an unambiguous recommendation based on the findings so far: "Bearing in mind the future health of their children, expectant mothers really should use paraben-free products during the sensitive periods of pregnancy and breastfeeding", says Lehmann. Many cosmetics products are already declared to be paraben-free; otherwise, this information can be obtained from the list of ingredients or using the ToxFox app, for instance." The researchers will continue to search for further potential effects of parabens in future investigations. "Epigenetic modifications that relate to the regulation of satiety are only one possible end point", says Polte. "Intergenerational effects of environmental factors have often been underestimated to date. We hope that our research will help to focus greater attention on such factors in future."

Without their keen sense of smell, mosquitoes wouldn't get very far. They rely on this sense to find a host to bite and spots to lay eggs. And without that sense of smell, mosquitoes could not locate their dominant source of food: nectar from flowers. 

"Interestingly, only females need blood. They use it to produce their eggs. However, males rely 100 percent on nectar to survive. Females also feed on nectar which increases they longevity and survival," said Chloé Lahondère, a research assistant professor from the Department of Biochemistry in the Virginia Tech College of Agriculture and Life Sciences.

Yet scientists know little about the scents that draw mosquitoes toward certain flowers, or repel them from others. This information could help develop less toxic and better repellents, more effective traps, and lead to an understanding of  how the mosquito brain responds to sensory information -- including the cues that, on occasion, lead a female mosquito to bite one of us.

Lahondère and the rest of the research team, which includes assistant professor Clément Vinauger from the Department of Biochemistry, as well as researchers from the University of Washington and UC San Diego, have discovered the chemical cues that lead mosquitoes to pollinate a particularly irresistible species of orchid -- the blunt-leaf orchid, also known as Platanthera obtusata.

As they report in a paper published in the Proceedings of the National Academy of Sciences, the orchid produces a finely balanced bouquet of chemical compounds that stimulate mosquitoes' sense of smell.

"We found that this orchid emits chemicals that attract different mosquito species, including Aedes aegypti, an invasive disease vector species that is not present in the native area of the orchid. And interestingly, all these mosquitoes respond to the same volatiles that the orchid emits," said Lahondère, who is the lead researcher for this study and an affiliated faculty member of the Global Change Center, an arm of the Fralin Life Sciences Institute at Virginia Tech. "This means that we can use this knowledge to develop new baits based on the flower scent and target a large diversity of mosquito species."

On their own, some of these chemicals have either attractive or repressive effects on the mosquito brain. When combined in the same ratio as they're found in the orchid, they draw in mosquitoes as effectively as a real flower. The research team also found that one of the scent chemicals that repels mosquitoes lights up the same region of the mosquito brain as DEET, a common and controversial mosquito repellant.

Their findings show how environmental cues from flowers can stimulate the mosquito brain as much as a warm-blooded host -- and can draw the mosquito toward a target or send it flying the other direction, said Jeffrey Riffell, a professor of biology at the University of Washington and senior author of the study.

The blunt-leaf orchid grows in cool, high-latitude climates across the Northern Hemisphere. From field stations in the Okanogan-Wenatchee National Forest in Washington state, the research team verified past research showing that local mosquitoes pollinate this species, but not its close relatives that grow in the same habitat.

When researchers covered the flowers with bags -- depriving the mosquitoes of a visual cue for the flower -- the mosquitoes would still land on the bagged flowers and attempt to feed through the canvas. Orchid scent obviously attracted the mosquitoes. To find out why, the team turned to the individual chemicals that make up the blunt-leaf orchid's scent.

"We often describe 'scent' as if it's one thing -- like the scent of a flower, or the scent of a person," said Riffell. "Scent is actually a complex combination of chemicals -- the scent of a rose consists of more than 300 -- and mosquitoes can detect the individual types of chemicals that make up a scent."

The blunt-leaf orchid is described to have a scent that has a grassy or musky odor, while its close relatives have a sweeter fragrance. The team used gas chromatography and mass spectroscopy to identify dozens of chemicals in the scents of the Platanthera species. Compared to its relatives, the blunt-leaf orchid's scent contained high amounts of a compound called nonanal, and smaller amounts of another chemical, lilac aldehyde.

Researchers also recorded the electrical activity in mosquito antennae, which detect scents. Both nonanal and lilac aldehyde stimulated antennae of mosquitoes that are native to the blunt-leaf orchid's habitat. But these compounds also stimulated the antennae of mosquitoes from other regions, including Anopheles stephensi, which spreads malaria, and Aedes aegypti, which spreads dengue, yellow fever, Zika, and other diseases.

"Beyond the notion that mosquitoes can actually be useful in that they pollinate endangered orchids, this study also provides new knowledge on the neural circuits that regulate mosquito olfaction. Down the line, these discoveries could lead to the identification of even more targets to prevent mosquitoes from finding us," said Vinauger, who is an affiliated faculty member of the Fralin Life Sciences Institute and the BIOTRANS program.

Experiments of mosquito behavior showed that both native and non-native mosquitoes preferred a solution of nonanal and lilac aldehyde mixed in the same ratio as found in blunt-leaf flowers. If the researchers omitted lilac aldehyde from the recipe, mosquitoes lost interest. If they added more lilac aldehyde -- at levels found in the blunt-leaf orchid's close relatives -- mosquitoes were indifferent or repelled by the scent.

Using techniques developed in Riffell's lab, the team peered directly into the brains of Aedes increpitus mosquitoes, which overlap with blunt-leaf orchids, and a genetically modified strain of Aedes aegypti previously developed by Riffell and co-author Omar Akbari, an associate professor at UC San Diego. They imaged calcium ions -- signatures of actively firing neurons -- in the antenna lobe, the region of the mosquito brain that processes signals from the antennae.

These brain imaging experiments revealed that nonanal and lilac aldehyde stimulate different parts of the antenna lobe -- and even compete with one another when stimulated: The region that responds to nonanal can suppress activity in the region that responds to lilac aldehyde, and vice versa. Whether this "cross talk" makes a flower attractive or repelling to the mosquito likely depends on the amounts of nonanal and lilac aldehyde in the original scent.

As far as future projects are concerned, Lahondère and Vinauger hope to use their recent findings from Washington to learn more about a relationship that exists between ornamental plants and invasive mosquitoes in Virginia.  

"Sugar feeding is one of our main projects right now. Based on our results, we hope to develop new efficient baits targeting important disease vectors, such as Ae. aegypti and Ae. albopictus, which are vectors of dengue, yellow fever, and Zika," said Lahondère, who is also an affiliated faculty member of the BIOTRANS program.

Aircraft contrails - the white streaks aircraft leave in the sky - could be as bad for the climate as their carbon dioxide (CO2) emissions. Now, new Imperial College London-led research has found that flight altitude changes of just 2000 feet could lessen their effect.

This, the researchers say, combined with using cleaner aircraft engines, could reduce contrail-caused harm to the climate by up to 90 per cent.
Lead author Dr Marc Stettler, of Imperial's Department of Civil and Environmental Engineering, said: "According to our study, changing the altitude of a small number of flights could significantly reduce the climate effects of aviation contrails. This new method could very quickly reduce the overall climate impact of the aviation industry."

The research is published in Environmental Science & Technology.

Contrail conundrum

When hot exhaust gases from aircraft meet the cold, low-pressure air of the atmosphere, they produce white streaks in the sky called 'condensation trails', or contrails.

The contrail fumes include black carbon particles, which provide surfaces on which moisture condenses to form ice particles. We see this condensation as fluffy white streaks.Most contrails last only a few minutes, but some spread and mix with other contrails and cirrus clouds, forming 'contrail cirrus' that linger for up to eighteen hours.

Previous research suggests that contrails and the clouds they help form have as much of a warming impact on the climate as aviation's cumulative CO2 emissions, because of an effect known as 'radiative forcing'. This is where the balance is disrupted between radiation coming to earth from the sun and heat emitted from the surface of the earth going out to space, forcing a change in the climate.

The key difference between CO2 and contrails, however, is that while CO¬2 will have an impact in the atmosphere for hundreds of years, the impact of contrails is short-lived and could therefore quickly be reduced.

Now, Dr Stettler and colleagues have used computer simulations to predict how changing aircraft altitudes might reduce the number of contrails and how long they linger, which would reduce their warming impact. This is because contrails only form and persist in thin layers of the atmosphere that have very high humidity. Because these layers are thin, small changes to flight altitudes would mean that aircraft could avoid these regions, leading to fewer contrails forming.

Using data from Japan's airspace, they found that just two per cent of flights were responsible for 80 per cent of radiation forcing within the airspace. Dr Stettler said: "A really small proportion of flights are responsible for the vast majority of contrail climate impact, meaning we can focus our attention on them."

Taking into account the congestion in the airspace above Japan, the team simulated these planes to fly either 2000 feet higher or lower than their actual flight paths and found that the contrail climate forcing could be cut by 59 per cent by altering the altitudes of 1.7 per cent of flights.

The diversion in flight paths caused less than a tenth of a per cent increase in fuel consumption - but, the researchers say, the reduced contrail formation more than offset the CO2 released by the extra fuel.

Dr Stettler suggests that their method of targeting only the few flights that cause the most climate forcing is the best way to avoid hikes in CO2 emissions. He said: "We're conscious that any additional CO2 released into the atmosphere will have a climate impact stretching centuries into the future, so we've also calculated that if we only target flights that wouldn't emit extra CO¬2, we can still achieve a 20 per cent reduction in contrail forcing."

The study's first author, Roger Teoh, also of Imperial's Department of Civil and Environmental Engineering, said: "Our simulation shows that targeting the few flights that cause the most harmful contrails, as well as making only small altitude changes, could significantly reduce the effect of contrails on global warming."

Industry impact

The researchers say aircraft engines themselves also play a part in how harmful contrails are. Black carbon particles are produced by incomplete fuel combustion, so new, more efficient engine combustion technology could help to reduce them by around 70 per cent.

This, combined with small altitude changes, could help reduce overall contrail harm by around 90 per cent.

Next, the researchers will refine their simulations to more accurately predict the characteristics and impact of contrails, and to evaluate the wider effects and practicalities of contrail mitigation strategies such as altering flight paths.