Pig kidney xenotransplantation performing optimally after 32 days in human body

Surgeons at NYU Langone Health have transplanted a genetically engineered pig kidney that continues to function well after 32 days in a man declared dead by neurologic criteria and maintained with a beating heart on ventilator support. This represents the longest period that a gene-edited pig kidney has functioned in a human, and the latest step toward the advent of an alternate, sustainable supply of organs for transplant.

The procedure, performed on July 14, 2023, and led by Robert Montgomery, MD, DPhil, the H. Leon Pachter, MD Professor of Surgery, chair of the Department of Surgery, and director of the NYU Langone Transplant Institute, was the fifth xenotransplant performed at NYU Langone. Observation is ongoing and the study will continue through mid-September 2023.

"This work demonstrates a pig kidney -- with only one genetic modification and without experimental medications or devices -- can replace the function of a human kidney for at least 32 days without being rejected," said Dr. Montgomery, who had previously performed the world's first genetically modified pig kidney transplant into a human decedent on September 25, 2021, followed by a second similar procedure on November 22, 2021. Surgeons with the Transplant Institute performed two genetically engineered pig heart transplants in summer 2022.

Removing Troublesome Gene Again Shows Promise

The first hurdle to overcome in xenotransplants is preventing so-called hyperacute rejection, which typically occurs just minutes after an animal organ is connected to the human circulatory system. By "knocking out" the gene that encodes the biomolecule known as alpha-gal -- which has been identified as responsible for a rapid antibody-mediated rejection of pig organs by humans -- immediate rejection has been avoided in all five xenotransplants at NYU Langone. Additionally, the pig's thymus gland, which is responsible for educating the immune system, was embedded underneath the outer layer of the kidney to stave off novel, delayed immune responses. The combination of modifications has been shown to prevent rejection of the organ while preserving kidney function.

To ensure the body's kidney function was sustained solely by the pig kidney, both of the transplant recipient's native kidneys were surgically removed. One pig kidney was then transplanted and started producing urine immediately without any signs of hyperacute rejection. During the observation phase, intensive care clinical staff maintained the decedent on support while the pig kidney's performance was monitored and sampled with weekly biopsies. Levels of creatinine, a bodily waste product found in the blood and an indicator of kidney function, were in the optimal range during the length of the study, and there was no evidence on biopsy of rejection.

The surgery was the latest in a larger study approved by a specific research ethics oversight board at NYU Langone and was performed after consultation with the New York State Department of Health. This important research, which study leaders say could save many lives in the future, was made possible by the family of a 57-year-old male who elected to donate his body after a brain death declaration and a circumstance in which his organs or tissues were not suitable for transplant.

LiveOnNY, the nonprofit organization that facilitates organ and tissue donation in the greater New York City area, was a critical partner in the effort to inform, support, and collaborate throughout the authorization process with the donor family.

A Big Leap Toward a New Organ Source

In the United States, there are more than 103,000 people on the waiting list for transplant, with nearly 88,000 of those waiting for a kidney, according to recent federal Organ Procurement and Transplantation Network (OPTN) data. In 2022, about 26,000 people received a kidney transplant. Meanwhile, nearly 808,000 people in the U.S. have end-stage renal disease.

"There are simply not enough organs available for everyone who needs one," said Dr. Montgomery, who received a hepatitis C-positive heart transplant himself in 2018. "Too many people are dying because of the lack of available organs, and I strongly believe xenotransplantation is a viable way to change that."

The kidney and thymus gland used in this procedure were procured from a GalSafeTM pig, an animal engineered by Revivicor, Inc., a subsidiary of United Therapeutics Corporation. In December 2020, the U.S. Food and Drug Administration (FDA) approved the GalSafe pig as a potential source for human therapeutics as well as a food source for people with alpha-gal syndrome, a meat allergy caused by a tick bite.

Less May Be More in Kidney Xenotransplants

While previous genetically engineered pig organ transplants have incorporated up to 10 genetic modifications, this latest study shows that a single-gene knockout pig kidney can still perform optimally for at least 32 days without rejection.

"We've now gathered more evidence to show that, at least in kidneys, just eliminating the gene that triggers a hyperacute rejection may be enough along with clinically approved immunosuppressive drugs to successfully manage the transplant in a human for optimal performance -- potentially in the long-term," said Dr. Montgomery.

The NYU Langone team used standard transplant immunosuppression medications combined with enhanced screening of porcine cytomegalovirus (pCMV) in the donor pig to ensure safety. Recent studies have shown pCMV may affect organ performance and potentially trigger organ failure. No pCMV was detected after 32 days, and close surveillance of porcine endogenous retrovirus (PERV), along with six other viruses of interest, was performed.

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Heredity and environment account for people's love of nature

Humans have a positive view of nature. But is this due to an approach we have learned while growing up, or is it something we are born with? The answer is 'Both', according to researchers at the University of Gothenburg and the Swedish University of Agricultural Sciences. Our love of nature is highly individual and should influence how we plan our cities, say the researchers.

It is well known that nature has a positive effect on people. In cities in particular, studies have shown that trees and other greenery contribute to people's wellbeing. However, experts do not agree on the reasons behind this phenomenon, known as biophilia.

Some believe that it is natural for humans to feel an automatic positive attachment because human development has occurred in nature. Others argue that there is no evidence for this, and that influences during our childhood determine how we view nature.

A wide range of factors involved

Researchers from the University of Gothenburg and the Swedish University of Agricultural Sciences (SLU) have reviewed several studies within this field that examine both innate factors and what individuals experience during their lives, primarily as children. In a new scientific article, the researchers conclude that both heredity and environment influence an individual's attitude to nature, but that a wide range of factors also influence how love of nature is expressed.

"We have been able to establish that many people have an unconscious positive experience of nature," says Bengt Gunnarsson, Professor Emeritus of Environmental Science at the University of Gothenburg. "But the biophilia hypothesis should be modified to link the variation in individuals' relationships with nature to an interaction between heredity and environmental influence."

Nature mean different things

This is because people react differently to nature. In a Japanese study, subjects were asked to walk in a forest and in a city while their heartbeat was measured. This showed that positive emotions while walking in a forest increased in 65% of people. Thus, far from everyone had a positive perception of nature. Another environmental psychology study found that research subjects are unconsciously drawn to nature instead of cities, and that this attraction was reinforced in those whose childhood was rich in nature.

"An additional study on identical and non-identical twins showed that a genetic component influences an individual's positive or negative relationship with nature," continues Bengt. "But the study also highlighted the importance of environment in terms of attitudes towards nature."

Moreover, nature can mean completely different things to different people. Some enjoy parks with lawns and planted trees, while others prefer being in the wilderness. The researchers believe that this variation is also determined by both heredity and environment.

"So it's important that we don't standardise nature when planning greenery in our towns and cities," adds Marcus Hedblom, a researcher at SLU and co-author of the article. "We shouldn't replace wild greenery with a park and assume that it will be good for everyone."

Urban nature brings many benefits

In today's urban planning, densification has been a common way to achieve a more sustainable city. This can sometimes come into conflict with efforts to offer nature in cities. A large number of studies suggest that urban parks and green spaces contribute to increased physical activity and recovery from stress. The greenery in our cities is also important in other respects. Trees can clean the air and provide shade to create a tolerable urban climate on hot days.

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Scientists discover external protein network can help stabilize neural connections

The Noelin family of secreted proteins bind to the external portion of AMPA glutamate receptors and stabilize them on the neuronal cellular membrane, a process necessary for transmission of full-strength signals between neurons, according to a study in mice from the National Eye Institute (NEI) and the University of Freiberg, Germany. Without this external, stabilizing protein network, the AMPA receptors are no longer retained at the synapse, leading to weak, short-lived synaptic signals. The findings not only provide insight into processes such as learning and memory but also the development of blinding conditions like glaucoma. The study was published in the journal Neuron. NEI is part of the National Institutes of Health.

"This study shows that Noelins have a crucial job in supporting synapse function in the brain and other neural tissues like the eye's retina," said Stanislav Tomarev, Ph.D., chief of NEI's Section on Retinal Ganglion Cell Biology and co-senior author of the report.

Neurons pass signals from one cell to the next via synapses, specialized connection points between the two cells. The main excitatory synapses in the brain are glutamatergic, meaning that they use the chemical messenger glutamate to transmit their signals across the synapse. The presynaptic "sending" cell emits glutamate, which travels across the synaptic cleft and is sensed by glutamate receptors on the postsynaptic "receiving" cell. These glutamate receptors are ion channels; when the channels sense glutamate, they open, generating a new neuronal signal within the postsynaptic cell. In order to generate a strong signal, sufficient receptors must be present in the correct location of the cell's surface at the synapse.

In a new study, a team of researchers led by Tomarev and Bernd Fakler, M.D., University of Freiberg, used biochemical and genetic methods to explore the complex network of extracellular proteins maintaining the localization of AMPA-type glutamate receptors at neural synapses.

The researchers first took mouse brain tissue, and isolated cellular membranes and their attached proteins. Using mass spectroscopy and specialized analytic techniques, the team worked out which proteins were associating with AMPA receptors in these membranes. The Noelin family of proteins (primarily Noelin 1, but also Noelins 2 and 3, also known as Olfactomedins 1, 2, and 3, respectively), were strongly associated with the AMPA receptors. The researchers also found secreted and membrane-anchored proteins like Neuritin and Brorin, which are known to be present at synapses.

To better understand how the Noelins help regulate neuronal activity, the researchers developed mice lacking all three Noelin proteins. Without Noelins present, synapses in the mouse hippocampus had many fewer AMPA glutamate receptors. And when the researchers attempted to stimulate neurons lacking Noelins, the neuronal signals were much lower than normal.

However, the neuronal signals weren't just lower. One of the key steps in memory formation is long-term neuron signaling, also known as long-term potentiation. This is achieved through recruitment and stabilization of additional glutamate receptors at the synapse over time, leading to a sustained signal through the neuron. In the brains of mice lacking Noelins, this stabilization didn't take place, meaning that not only were the neural signals low, they were short-lived as well.

"While this first study showed the Noelins' role in the brain, these proteins are highly prevalent in the retina as well," Tomarev said. "Our next task is to understand how changes in these secreted protein networks contribute to the development of retinal disorders, including glaucoma."

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New type of star gives clues to mysterious origin of magnetars

Magnetars are the strongest magnets in the Universe. These super-dense dead stars with ultra-strong magnetic fields can be found all over our galaxy but astronomers don't know exactly how they form. Now, using multiple telescopes around the world, including European Southern Observatory (ESO) facilities, researchers have uncovered a living star that is likely to become a magnetar. This finding marks the discovery of a new type of astronomical object -- massive magnetic helium stars -- and sheds light on the origin of magnetars.

Despite having been observed for over 100 years, the enigmatic nature of the star HD 45166 could not be easily explained by conventional models, and little was known about it beyond the fact that it is one of a pair of stars, is rich in helium and is a few times more massive than our Sun.

"This star became a bit of an obsession of mine," says Tomer Shenar, the lead author of a study on this object published today in Science and an astronomer at the University of Amsterdam, the Netherlands. "Tomer and I refer to HD 45166 as the 'zombie star'," says co-author and ESO astronomer Julia Bodensteiner, based in Germany. "This is not only because this star is so unique, but also because I jokingly said that it turns Tomer into a zombie."

Having studied similar helium-rich stars before, Shenar thought magnetic fields could crack the case. Indeed, magnetic fields are known to influence the behaviour of stars and could explain why traditional models failed to describe HD 45166, which is located about 3000 light-years away in the constellation Monoceros. "I remember having a Eureka moment while reading the literature: 'What if the star is magnetic?'," says Shenar, who is currently based at the Centre for Astrobiology in Madrid, Spain.

Shenar and his team set out to study the star using multiple facilities around the globe. The main observations were conducted in February 2022 using an instrument on the Canada-France-Hawaii Telescope that can detect and measure magnetic fields. The team also relied on key archive data taken with the Fiber-fed Extended Range Optical Spectrograph (FEROS) at ESO's La Silla Observatory in Chile.

Once the observations were in, Shenar asked co-author Gregg Wade, an expert on magnetic fields in stars at the Royal Military College of Canada, to examine the data. Wade's response confirmed Shenar's hunch: "Well my friend, whatever this thing is -- it is definitely magnetic."

Shenar's team had found that the star has an incredibly strong magnetic field, of 43,000 gauss, making HD 45166 the most magnetic massive star found to date. "The entire surface of the helium star has a magnetic field almost 100,000 times stronger than Earth's," explains co-author Pablo Marchant, an astronomer at KU Leuven's Institute of Astronomy in BelgiumThis observation marks the discovery of the very first massive magnetic helium star. "It is exciting to uncover a new type of astronomical object," says Shenar, "especially when it's been hiding in plain sight all along."

Moreover, it provides clues to the origin of magnetars, compact dead stars laced with magnetic fields at least a billion times stronger than the one in HD 45166. The team's calculations suggest that this star will end its life as a magnetar. As it collapses under its own gravity, its magnetic field will strengthen, and the star will eventually become a very compact core with a magnetic field of around 100 trillion gauss -- the most powerful type of magnet in the Universe.

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America's wealthiest 10% responsible for 40% of US greenhouse gas emissions

A new study, led by the University of Massachusetts Amherst, reveals that the wealthiest Americans, those whose income places them in the top 10% of earners, are responsible for 40% of the nation's total greenhouse gas emissions. The study, published in  PLOS Climate, is the first to link income, especially income derived from financial investments, to the emissions used in generating that income. The authors suggest that policymakers adopt taxes focused on shareholders and the carbon intensity of investment incomes in order to equitably meet the goal of keeping the global temperature to 1.5 C of warming.

Scientists and environmentalists have long known that consumption -- the amount and kind of food we eat, the vehicles we drive and all the stuff we buy -- is closely linked to greenhouse gas emission. Traditional environmental policy has then sought to either limit consumption or guide it into more environmentally friendly avenues: replacing red meat with plant-based diets or swapping a gas-guzzler for an electric vehicle.

"But," says Jared Starr, a sustainability scientist at UMass Amherst and the lead author of the new study, "consumption-based approaches to limiting greenhouse gas emissions are regressive. They disproportionately punish the poor while having little impact on the extremely wealthy, who tend to save and invest a large share of their income. Consumption-based approaches miss something important: carbon pollution generates income, but when that income is reinvested into stocks, rather than spent on necessities, it isn't subject to a consumption-based carbon tax."

"What happens," Starr asks, "when we focus on how emissions create income, rather than how they enable consumption?"

An answer to that seemingly simple question, however, is fraught with difficulty, because though it's relatively easy to capture a snapshot of wages and salaries -- the main sources of income for 90% of Americans -- it has been very difficult to get a sense of the investment income that makes up a large source of the richest Americans' wealth.

To solve this problem, Starr and his colleagues looked at 30 years' worth of data, drawing first on a database containing over 2.8 billion inter-sectoral financial transfers and following the flow of carbon and income through these transactions. This allowed them to calculate two different values: supplier-based and producer-based greenhouse gas emissions of income.

Supplier-based emissions are those created by industries that supply fossil fuels to the economy. For instance, the operational emissions released by fossil fuel companies are actually quite low, but they make enormous profits by selling oil to others who will burn it.

Producer-based emissions are those directly released by the operation of the business itself -- like a coal-fired power plant.

With these two figures in hand, Starr and his co-authors then linked their emissions data with another database containing detailed demographic and income data for over 5 million Americans. This database parses out income sources differentiating active income -- the wages or salaries earned through employment -- from the passively generated investment income.

Not only did the team find that over 40% of U.S. emissions were attributable with the income flows of the top 10%, they also discovered that the top 1% of earners alone generate 15 -- 17% of the nation's emissions. In general, white, non-Hispanic households had the highest emission-linked income and Black households the lowest. Emissions tended to increase with age, peaking with the 45-54 age group, before declining.

The team also identified "super emitters" with extremely high emissions intensity. These are almost exclusively among the top 0.1% of households, which are overrepresented in the fields of finance, real estate and insurance, manufacturing, and mining and quarrying.

"This research gives us insight into the way that income and investments obscure emissions responsibility," says Starr. "For example, 15 days of income for a top 0.1% household generates as much carbon pollution as a lifetime of income for a household in the bottom 10%. An income-based lens helps us focus in on exactly who is profiting the most from climate-changing carbon pollution, and design policies to shift their behavior."

In particular, Starr and his colleagues point to income and shareholder-based taxation -- rather than taxing consumables.

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The modern sea spider had started to diversify by the Jurassic, study finds

An extremely rare collection of 160-million-year-old sea spider fossils from Southern France are closely related to living species, unlike older fossils of their kind.

These fossils are very important to understand the evolution of sea spiders. They show that the diversity of sea spiders that still exist today had already started to form by the Jurassic.

Lead author Dr Romain Sabroux from the University of Bristol's School of Earth Sciences, said: "Sea spiders (Pycnogonida), are a group of marine animals that is overall very poorly studied.

"However, they are very interesting to understand the evolution of arthropods [the group that includes insects, arachnids, crustaceans, centipedes and millipedes] as they appeared relatively early in the arthropod tree of life. That's why we are interested in their evolution.

"Sea spider fossils are very rare, but we know a few of them from different periods. One of the most remarkable fauna, by its diversity and its abundance, is the one of La Voulte-sur-Rhône that dates back to the Jurassic, some 160 million years ago."

Unlike older sea spider fossils, the La Voulte pycnogonids are morphologically similar (but not identical) to living species, and previous studies suggested they could be closely related to living sea spider families. But these hypotheses were restricted by the limitation of their observation means. As it was impossible to access what was hidden in the rock fossils, Dr Sabroux and his team travelled to Paris and set out to investigate this question with cutting-edge approaches.

Dr Sabroux explained: "We used two methods to reinvestigate the morphology of the fossils: X-ray microtomography, to 'look inside' the rock, find morphological features hidden inside and reconstruct a 3D model of the fossilised specimen; and Reflectance Transformation Imaging, a picture technic that relies on varied orientation of the light around the fossil to enhance the visibility of inconspicuous features on their surface.

"From these new insights, we drew new morphological information to compare them with extant species," explained Dr Sabroux.

This confirmed that these fossils are close relatives to surviving pycnogonids. Two of these fossils belong to two living pycnogonid families: Colossopantopodus boissinensis was a Colossendeidae while another, Palaeoendeis elmii was an Endeidae. The third species, Palaeopycnogonides gracilis, seems to belong to a family that has disappeared today.

"Today, by calculating the difference between the DNA sequences of a sample of species, and using DNA evolution models, we are able to estimate the timing of the evolution that bind these species together," added Dr Sabroux.

"This is what we call a molecular clock analysis. But quite like a real clock, it needs to be calibrated. Basically, we need to tell the clock: 'we know that at that time, that group was already there.' Thanks to our work, we now know that Colossendeidae, and Endeidae were already 'there' by the Jurassic."

Now, the team can use these minimal ages as calibrations for the molecular clock, and investigate the timing of Pycnogonida evolution. This can help them understand, for example, how their diversity was impacted by the different biodiversity crises that distributes over the Earth history.

They also plan to investigate other pycnogonid fossil faunae such as the fauna of Hunsrück Slate, in Germany, which dates from the Devonian, some 400 million years ago.

With the same approach, they will aim to redescribe these species and understand their affinities with extant species; and finally, to replace in the tree of life of Pycnogonida all the pycnogonid fossils from all periods.

Dr Sabroux added: "These fossils give us an insight of sea spiders living 160 million years ago.

"This is very exciting when you have been working on the living pycnogonids for years.

"It is fascinating how these pycnogonids look both very familiar, and very exotic. Familiar, because you can definitely recognize some of the families that still exist today, and exotic because of small differences like the size of the legs, the length of the body, and some other morphological characteristics that you do not find in modern species.

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Iceman Ötzi: Dark skin, bald head, Anatolian ancestry

A research team has used advanced sequencing technology to analyze Ötzi's genome to obtain a more accurate picture of the Iceman's appearance and genetic origins.

Ötzi's genome was decoded for the first time more than ten years ago. This was also the first time the genome of a mummy had been sequenced. The results provided important insights into the genetic makeup of prehistoric Europeans. Advances in sequencing technology have now enabled a research team from the Max Planck Institute for Evolutionary Anthropology and Eurac Research to reconstruct Ötzi's genome more accurately. The results of this recent analysis refine the Iceman's genetic picture: compared to other contemporary Europeans, Ötzi's genome has an unusually high proportion of genes in common with those of early farmers from Anatolia. And, contrary to previous findings, at the time of his death, Ötzi had advanced hair loss and may have even been bald. Furthermore, his skin was darker than previously thought. Ötzi's genes also show a predisposition to diabetes and obesity.

The genetic makeup of most present-day Europeans has resulted mainly from the admixture of three ancestral groups: western hunter-gatherers gradually merged with early farmers who migrated from Anatolia about 8,000 years ago and who were later on joined by Steppe Herders from Eastern Europe, approximately 4,900 years ago.

The initial analysis of the Iceman's genome revealed genetic traces of these Steppe Herders. However, the refined new results no longer support this finding. The reason for the inaccuracy: the original sample had been contaminated with modern DNA. Since that first study, not only have sequencing technologies advanced enormously, but many more genomes of other prehistoric Europeans have been fully decoded, often from skeletal finds. This has made it possible to compare Ötzi's genetic code with his contemporaries. The result: among the hundreds of early European people who lived at the same time as Ötzi and whose genomes are now available, Ötzi's genome has more ancestry in common with early Anatolian farmers than any of his European counterparts.

Ötzi's ancestry and appearance

The research team concludes that the Iceman came from a relatively isolated population that had very little contact with other European groups. "We were very surprised to find no traces of Eastern European Steppe Herders in the most recent analysis of the Iceman genome; the proportion of hunter-gatherer genes in Ötzi's genome is also very low. Genetically, his ancestors seem to have arrived directly from Anatolia without mixing with hunter gatherer groups," explains Johannes Krause, head of the Department of Archaeogenetics at the Max Planck Institute for Evolutionary Anthropology in Leipzig, and co-author of the study.

The study also yielded new results about Ötzi's appearance. His skin type, already determined in the first genome analysis to be Mediterranean-European, was even darker than previously thought. "It's the darkest skin tone that has been recorded in contemporary European individuals," explains anthropologist Albert Zink, study co-author and head of the Eurac Research Institute for Mummy Studies in Bolzano: "It was previously thought that the mummy's skin had darkened during its preservation in the ice, but presumably what we see now is actually largely Ötzi's original skin color. Knowing this, of course, is also important for the proper conservation of the mummy."

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Using supernovae to study neutrinos' strange properties

In a new study, researchers have taken an important step toward understanding how exploding stars can help reveal how neutrinos, mysterious subatomic particles, secretly interact with themselves.

One of the less well-understood elementary particles, neutrinos rarely interact with normal matter, and instead travel invisibly through it at almost the speed of light. These ghostly particles outnumber all the atoms in the universe and are always passing harmlessly through our bodies, but due to their low mass and lack of an electric charge they can be incredibly difficult to find and study.

But in a study published today in the journal Physical Review Letters, researchers at The Ohio State University have established a new framework detailing how supernovae -- massive explosions that herald the death of collapsing stars -- could be used as powerful tools to study how neutrino self-interactions can cause vast cosmological changes in the universe.

"Neutrinos only have very small rates of interaction with typical matter, so it's difficult to detect them and test any of their properties," said Po-Wen Chang, lead author of the study and a graduate student in physics at Ohio State. "That's why we have to use astrophysics and cosmology to discover interesting phenomena about them."

Thought to have been important to the formation of the early universe, neutrinos are still puzzling to scientists, despite having learned that they originate from a number of sources, such as in nuclear reactors or the insides of dying stars. But by calculating how self-interactions would affect the neutrino signal from Supernova 1987A, the nearest supernova observed in modern times, researchers found that when neutrinos do interact with themselves, they form a tightly coupled fluid that expands under relativistic hydrodynamics -- a branch of physics that deals with how flows impact solid objects in one of two different ways.

In the case of what's called a "burst outflow," the team theorizes that much like popping a highly pressurized balloon in the vacuum of space would push energy outward, a burst produces a neutrino fluid that moves in all directions. The second case, described as a "wind outflow," imagines a highly pressurized balloon with many nozzles, wherein neutrinos escape at a more constant flow rate, similar to a jet of steady wind.

While the wind-outflow theory is more likely to take place in nature, said Chang, if the burst case is realized, scientists could see new observable neutrino signatures emitted from supernovae, allowing unprecedented sensitivity to neutrino self-interactions.

One of the reasons it's so vital to understand these mechanisms is that if neutrinos are acting as a fluid, that means they are acting together, as a collective. And if the properties of neutrinos are different as a collective than individually, then the physics of supernovae could experience changes too. But whether these changes are due solely to the burst case or the outflow case remains to be seen.

"The dynamics of supernovae are complicated, but this result is promising because with relativistic hydrodynamics we know there's a fork in the road in understanding how they work now," said Chang.

Still, further research needs to be done before scientists can cross off the possibility of the burst case happening inside supernovae as well.

Despite these uncertainties, the study is a huge milestone in answering the decades-old astrophysical issue of how neutrinos actually scatter when ejected from supernovae, said John Beacom, co-author of the study and a professor of physics and astronomy at Ohio State. This study found that in the burst case, unprecedented sensitivity to neutrino self-interactions is possible even with sparse neutrino data from SN 1987A and conservative analysis assumptions.

"This problem has lain basically untouched for 35 years," said Beacom. "So even though we were not able to completely solve how neutrinos affect supernovae, what we're excited about is that we were able to make a substantial step forward."

Down the road, the team hopes their work will be used as a stepping stone to further investigate neutrino self-interactions. Yet because only about two or three supernovae happen per century in the Milky Way, it's likely researchers will have to wait decades more to collect enough new neutrino data to prove their ideas.

"We're always praying for another galactic supernova to happen somewhere and soon, but the best we can do is try to build on what we know as much as possible before it happens," said Chang.

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Oceans release microplastics into the atmosphere

Tiny plastic particles can be found in the sea air even far from coasts, according to a study recently published in the journal Nature Communications. The microplastics come from partly unexpected sources.

Microplastic particles are present in the marine atmosphere even in remote parts of the world. These tiny particles come from land sources but are also re-emitted into the atmosphere from the sea, a study by a team of German and Norwegian researchers led by Dr Barbara Scholz-Böttcher of the University of Oldenburg has shown. The scientists analysed air samples taken from various sites along the Norwegian coast all the way up to the Arctic region. The results have now been published in the scientific journal Nature Communications.

"With our study, we present data on the mass load of different types of plastic in the marine atmosphere for the first time," said Isabel Goßmann, a doctoral candidate at the University of Oldenburg's Institute for Chemistry and Biology of the Marine Environment (ICBM) and first author of the paper. The research team collected the samples during an expedition with the Research Vessel Heincke in 2021. The northernmost destination was Bear Island, the most southerly island of the Svalbard archipelago which lies halfway between the mainland and the archipelago's largest island, Spitsbergen. The team used two different devices to collect air samples. The devices actively pumped in air and were mounted on the bow of the research vessel at a height of twelve metres.

Different types of plastics identified

The scientists analysed the air samples using pyrolysis-gas chromatography-mass spectrometry. With this method they were able to identify and quantify the different types of plastics in the atmosphere through thermal degradation and selective analysis. They then performed model calculations and reconstructed the sources and distribution paths of the particles, each of which is just a few thousandths of a millimetre in size.

The analysis revealed the omnipresence of polyester particles. Polyethylene terephthalate particles, which presumably entered the atmosphere in the form of textile fibres, were detected in all samples. Other plastic types were also present, including polypropylene polycarbonate and polystyrene. Tire wear particles, the tiny debris abraded from tires during driving and especially braking, were identified as another major source of microplastics. The researchers measured concentrations of up to 37.5 nanograms (one nanogram = one-billionth of a gram) of microplastics per cubic metre of air. "These pollutants are ubiquitous. We find them even in remote polar regions," Goßmann stressed.

Until now, little was known about microplastics pollution levels including tire wear particles in the marine atmosphere. "There are only a handful of studies on the concentration of these pollutants in the air," said team leader Scholz-Böttcher. "Our model calculations indicate that the microplastics in the marine atmosphere come from direct sources on the land as well as from the sea," she added. The team posits that plastic particles floating near the sea surface enter the atmosphere via sea spray and bursting air bubbles produced during stormy weather, for example.

Ships are also a source of microplastics

Microplastics find their way into seawater via rivers, but also through the atmosphere -- particles are washed out of the atmosphere by rain, for example. Another potential source is ship traffic: in an earlier study, a team led by Scholz-Böttcher demonstrated that in the open North Sea, the paint and coatings used on ships is the main source of microplastics. In the current study, chemicals such as polyurethanes and epoxy resins typically used in paints and coatings for ships were also found in the air samples.

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Genetically modified neural stem cells show promising therapeutic potential for spinal cord injury

A research team co-led by City University of Hong Kong (CityU) and The University of Hong Kong (HKU) has recently made a significant advancement in spinal cord injury treatment by using genetically modified human neural stem cells (hNSCs). They found that specifically modulating a gene expression to a certain level in hNSCs can effectively promote the reconstruction of damaged neural circuits and restore locomotor functions, offering great potential for new therapeutic opportunities for patients with spinal cord injury.

Traumatic spinal cord injury is a devastating condition that commonly results from accidents such as falls, car crashes or sport-related injuries. Spinal neurons with long axons play critical roles in transmitting signals between the brain and the rest of the body, controlling our movement and sensory perception. Spinal cord injury causes irreversible damage to neurons and axons, which significantly interrupts signal transmission, hence leading to defective locomotion and somatosensory functions.

"Currently, there are no effective clinical management or treatment regimens for patients with spinal cord injury, often leaving them with lifelong disabilities," explained Professor Jessica Liu Aijia, Assistant Professor in the Department of Neuroscience at CityU and the co-leader of the research. "While recent progress has been made in promoting spinal cord regeneration through transplantation of hNSCs derived from human induced pluripotent stem cells, the degree of functional recovery obtained has been modest. This is largely due to the hostile micro-environment around the lesion site, such as the formation of barrier-like structures called astroglial scars and the lack of neurotrophic factors in adults for neuronal differentiation. These factors hinder functional neuronal regeneration, resulting in prolonged repairing and limited functional recovery."

A gene -- SOX9 was reported with a high-level expression at the injury site in previous studies, and the gene itself is the leading cause of the glial scars' formation and the hindrance of neuronal survival and differentiation. To overcome the adverse effects of the post-injury micro-environment, the joint-research team engineered the transplanted neural stem cells with a graded reduction of SOX9 by approximately 50%.

The genetically modified hNSCs expressing half-dose of SOX9 resulted in robust neuronal differentiation and maturation (a process by which immature cells in the nervous system become specialised nerve cells) after transplantation in a hostile microenvironment, promoting neural circuits reconstruction in the spinal cord within a shorter period of time. It also remarkably reduced glial scar accumulation, facilitating long-distance axon outgrowth. The team recorded a large number of axons extending more than 35mm at 3 months post-graft, while relatively less in number with shorter extensions to 25mm with non-modified neural stem cells.

To further explore the therapeutic effects of the modified hNSCs in treating spinal cord injury, the research team used a severe spinal cord injury rat model to evaluate the locomotion recovery after transplantation, including grid walking and consecutive walk. The former recorded limb coordination, such as the capability to grasp a grid rung with correct placement, and the latter recorded stepping patterns to demonstrate their gait and fingertip motor ability.

Compared to rats' graft with non-modified hNSCs, rats' graft with SOX9 gene-modified hNSCs performed much better in placing their affected hind paws on the grid, with fewer misdirected steps after 10 weeks post-injury. In addition, these treated rats demonstrated a good gait with clear paw position and toe movement when walking across a metre-long narrow corridor.

"Our findings reveal a new treatment direction by using a genetically modified strategy to alter the grafts' response to the deleterious microenvironment in vivo after injury, improving cell tolerance to the niche and self-differentiation potential. This brings a new treatment direction for repairing damaged spinal cord," said Professor Liu.

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'Resurrecting' the legendary figure behind Count Dracula

Vlad III, known as Vlad the Impaler, was a 15th century prince and military leader who was so terrifying, he's thought to have inspired the creation of the literary vampire, Count Dracula. Now, a scientific examination of his letters is giving new insights into his health. Researchers now reporting in ACS' Analytical Chemistry, say the results suggest that Vlad probably had skin and respiratory conditions and could have even cried literal tears of blood.

The legendary figure's official title was Vlad III, Voivode of Wallachia, and he lived in the southern region of Romania in the mid-1400s. Of course, there's no evidence that Vlad III was a vampire, but he was feared for his ruthlessness. Some estimates place his death toll at over 80,000 people, many dying by impalement, earning him his nickname. He was also referred to as Vlad Drăculea, translating to "the son of the dragon," which many believe inspired the eponymous character from the novel Dracula.

Though over 500 years have passed since Vlad's reign, some artifacts have remained, including several letters he penned at different points throughout his life. The molecules and proteins present on documents and other relics like these can provide scientists with a unique understanding of the life and times of people from the past. So, Vincenzo Cunsolo and colleagues wanted to, for the first time, investigate these letters to learn more about the health of the infamous Vlad Drăculeaa, as well as the environment he lived in.

To uncover the letters' secrets, the researchers used a specialized plastic film called EVA, or ethylene-vinyl acetate, to extract any proteins or small molecules from the paper without damaging it. These extracts were then analyzed with mass spectrometry, allowing researchers to characterize thousands of different peptides. Of these, the team focused on those with the most advanced deamidation, a form of protein degradation that occurs with age. The most degraded proteins were likely the oldest, and therefore, they are the most likely to be from Vlad compared to newer, less-degraded proteins that could have originated from other people handling the letters more recently. A total of 16 proteins were of human origin, relating to skin, breathing and blood.

The researchers say that the data they acquired, although not exhaustive, suggest that Vlad could have suffered from respiratory issues, and potentially even a condition called hemolacria, which would have caused him to cry tears of blood -- quite fitting for such a spooky character. Other proteins identified by the team indicate that he could have been exposed to certain, plague-related bacteria or even pesky fruit flies. In all, the researchers say that this work helps shed light on some important documents of the past, as well as the people who may have written them.

From Science Daily

Key role of ice age cycles in early human interbreeding

A study published in Science indicates that climatic shifts over the past 400,000 years have influenced Neanderthal and Denisovan interbreeding.

Recent paleogenomic research revealed that interbreeding was common among early human species. However, little was known about when, where, and how often this hominin interbreeding took place. Using paleoanthropological evidence, genetic data, and supercomputer simulations of past climate, a team of international researchers has found that interglacial climates and corresponding shifts in vegetation created common habitats for Neanderthals and Denisovans, increasing their chances for interbreeding and gene flow in parts of Europe and central Asia.

Contemporary humans carry in their cells a small amount of DNA derived from Neanderthals and Denisovans. "Denny," a 90,000-year-old fossil individual, recently identified as the daughter of a Denisovan father and a Neanderthal mother, bears testimony to the possibility that interbreeding was quite common among early human species. But when, where, and at what frequency did this interbreeding take place?

In a recent study published in Science on 10 August 2023, researchers from Korea and Italy have joined hands to answer this question. Using fossil data, supercomputer simulations of past climate, and insights obtained from genomic evidence, the team was able to identify habitat overlaps and contact hotspots of these early human species. Dr. Jiaoyang Ruan, Postdoctoral Researcher at IBS Center for Climate Physics (ICCP), South Korea, explains, "Little is known about when, where, and how frequently Neanderthals and Denisovans interbred throughout their shared history. As such, we tried to understand the potential for Neanderthal-Denisovan admixture using species distribution models that bring extensive fossil, archeological, and genetic data together with transient Coupled General Circulation Model simulations of global climate and biome."

The researchers found that Neanderthals and Denisovans had different environmental preferences to start with. While Denisovans were much more adapted to colder environments, such as the boreal forests and the tundra region in northeastern Eurasia, their Neanderthal cousins preferred the warmer temperate forests and grasslands in the southwest. However, shifts in the Earth's orbit led to changes in climatic conditions and hence vegetation patterns. This triggered the migration of both these hominin species towards geographically overlapping habitats, thus increasing the chance of their interbreeding.

The researchers further used insights gained from their analysis to determine the contact hotspots between Neanderthals and Denisovans. They identified Central Eurasia, the Caucasus, the Tianshan, and the Changbai mountains as the likely hotspots. Identification of these habitat overlaps also helped the researchers place 'Denny' within the climatic context and even confirmed the other known episodes of genetic interbreeding. The researchers also noted that the Denisovans and Neanderthals would have had a high probability of contact in the Siberian Altai during ~ 340-290, ~240-190 and ~130-80 thousand years ago.

To further elucidate the factors that triggered the 'east-west interbreeding seesaw,' the team examined the change in vegetation patterns over Eurasia over the past 400 thousand years. They observed that elevated atmospheric CO2 concentrations and mild interglacial conditions caused an eastward expansion of the temperate forest into central Eurasia, and the dispersal of Neanderthals into Denisovan lands. On the contrary, lower CO2 concentrations and corresponding harsher glacial climate potentially caused a fragmentation of their habitats, leading to lesser interactions and interbreeding events.

"Pronounced climate-driven zonal shifts in the main overlap region of Denisovans and Neanderthals in central Eurasia, which can be attributed to the response of climate and vegetation to past variations in atmospheric CO2 and northern hemisphere ice-sheet volume, influenced the timing and intensity of potential interbreeding events," remarks senior author Axel Timmermann, Director, ICCP and Professor at Pusan National University, South Korea.

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New research offers solutions to improve drinking water access in developing countries

In 2020, 771 million people worldwide still lacked access to clean drinking water, according to UNICEF and the World Health Organization.

For this reason, many nongovernmental organizations (NGOs) prioritize building new water projects, including handpumps and small piped systems, to bring clean water to rural areas of developing countries.

Alfonso Pedraza-Martinez

New research from Alfonso Pedraza-Martinez, the Greg and Patty Fox Collegiate Professor of IT, Analytics and Operations in the University of Notre Dame's Mendoza College of Business, examines the critical problem of drinking water access in rural areas of developing countries and recommends optimal locations to build new water projects.

"Improving Drinking Water Access and Equity in Rural Sub-Saharan Africa," forthcoming in the journal Production and Operations Management, studies access to drinking water in Tigray, Ethiopia, where millions of people walk hours each day to access communal water. The study, co-authored by Chengcheng Zhai, Kurt Bretthauer and Jorge Mejia from Indiana University, pulls from field research conducted in Tigray and collaborations with local and international NGOs.

"The burden of getting water falls mostly on women and children," said Pedraza-Martinez, who specializes in humanitarian operations and disaster management. "It is not rare to see a woman accompanied by her children carrying a heavy jerrycan full of water back home in the scorching hot weather."

Due to a lack of local government solutions, NGOs build water projects that extract underground water to reduce the population's distance and time to access it. In collaboration with U.S. NGO Charity: Water and Ethiopian NGO Relief Society of Tigray, the team worked to understand the roles of the different stakeholders.

"Building water projects is expensive and funding is scarce," Pedraza-Martinez said. "NGOs must select locations for new water projects while navigating tight budget constraints and very limited access to data on demand locations.

"We discovered that communities actively participate in the management of existing water projects, so we propose that two neighbor communities collaborate, pooling their demand, to increase the potential supply for both communities."

The team created a unique dataset with current demand and distance to an existing water project in Tigray. Using analytics, they built an optimization or ideal solution (centralized model) that incorporates community collaboration, and compared its solutions with the current practice that serves each community separately.

The community collaboration model proved to be a better solution -- in terms of distance to water and equity in the access to water -- than the other models they considered. The "minimax" model adjusted the objective to minimizing the maximum distance to water and the equitable allocation model adjusted the current per capita budget allocations to assign more budget to beneficiaries who are further from water.

"When Ethiopian communities (kebeles) collaborate to access water as a single, larger community, it removes geopolitical boundaries for water purposes," Pedraza-Martinez said. "It gives people who live on the outskirts of one kebele the option of walking a shorter distance toward another to use a hand pump or other water source, rather than walking a longer distance to find one in their own kebele. If there is cooperation, this solution is very effective to reduce distance and increase equity."

Motivated by Ethiopia's current civil war, the team also created a model to study ways to improve drinking water access amid supply shocks.

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Elephant ancestors´ teeth evolved in response to long term changes in diet and climate in Africa

A new study shows that the cheek teeth of proboscideans (elephants and their ancient relatives) evolved in response to dietary changes due to vegetation changes and climate change in East Africa during the last 26 million years.

The latest study about of proboscideans (elephants and their ancient relatives) from the University of Helsinki provides proof that some proboscideans started to adapt to locally grass-rich environments in East Africa first by changing their behavior and starting to feed more on grasses. This happened in some lineages of proboscideans, such as choerolophodonts, much earlier than has been thought until now, about 23 to 11 million years ago in parts of East Africa

Also, around 7 million years ago in the lake Turkana region, increasingly grass-rich diets of the earliest true elephants were associated with dryer and more grass-rich savanna environments than elsewhere in East Africa.

"This supports the hypothesis of such regions as "species-factories" where evolutionary adaptation to changing environmental conditions first centered around," says Juha Saarinen from the University of Helsinki, who led the research.

Feeding on grasses is more demanding on teeth than feeding on most other kinds of plants due to a high content of mineral grains called phytoliths in their leaves, causing heavy abrasion on teeth.

Nonetheless, during the Early and Middle Miocene the choerolophodont lineage of proboscideans were able to shift to more grass-rich diets with relatively modest changes in the morphology of their teeth.

Since about 10 million years ago, major changes in climate had a more profound effect on the evolution of proboscidean teeth in East Africa, especially the evolution of true elephants (Elephantidae) with highly specialized high-crowned, multi-ridged molar teeth.

"We were able to show that the strongest peaks of drying of the East African climate during the last 7 million years (for example about 4 and 2 million years ago) correspond with evolutionary bursts in the increase of tooth crown height and the number of ridges on the molar teeth, while these evolutionary changes did not reverse during periods of less harsh climatic conditions" says Saarinen.

"This supports earlier suggestions that adaptive traits in organisms are adaptations to extreme rather than average environmental conditions."

Comparing evidence of past vegetation and the diet of elephants during the last 7 million years also showed an increase of grasslands and increasing dominance of grass-feeding elephants with highly specialized teeth throughout that period in most parts of East Africa. However, during the last 100,000 years this situation changed probably because of drastic fluctuations in global climate and eventually only the dietarily more generalist modern African savanna elephant (Loxodonta africana) with less specialized teeth survived in East Africa. Ecological generalism might similarly explain the survival of Asian elephant (Elephas maximus) in Asia, while the African forest elephant (L. cyclotis) was able to find refuge in more forested parts of Central and Western Africa.

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Microplastic pollution: Plants could be the answer

Could plants be the answer to the looming threat of microplastic pollution? Scientists at UBC's BioProducts Institute found that if you add tannins -- natural plant compounds that make your mouth pucker if you bite into an unripe fruit -- to a layer of wood dust, you can create a filter that traps virtually all microplastic particles present in water.

While the experiment remains a lab set-up at this stage, the team is convinced that the solution can be scaled up easily and inexpensively once they find the right industry partner.

Microplastics are tiny pieces of plastic debris resulting from the breakdown of consumer products and industrial waste. Keeping them out of water supplies is a huge challenge, says Dr. Orlando Rojas, the institute's scientific director and the Canada Excellence Research Chair in Forest Bioproducts.

He noted one study which found that virtually all tap water is contaminated by microplastics, and other research which states that more than 10 billion tons of mismanaged plastic waste will be dispersed in the environment by 2025.

"Most solutions proposed so far are costly or difficult to scale up. We're proposing a solution that could potentially be scaled down for home use or scaled up for municipal treatment systems. Our filter, unlike plastic filters, does not contribute to further pollution as it uses renewable and biodegradable materials: tannic acids from plants, bark, wood and leaves, and wood sawdust -- a forestry byproduct that is both widely available and renewable."

Captures a wide variety of plastics

For their study, the team analyzed microparticles released from popular tea bags made of polypropylene. They found that their method (they're calling it "bioCap") trapped from 95.2 per cent to as much as 99.9 per cent of plastic particles in a column of water, depending on plastic type. When tested in mouse models, the process was proved to prevent the accumulation of microplastics in the organs.

Dr. Rojas, a professor in the departments of wood science, chemical and biological engineering, and chemistry at UBC, adds that it's difficult to capture all the different kinds of microplastics in a solution, as they come in different sizes, shapes and electrical charges.

"There are microfibres from clothing, microbeads from cleansers and soaps, and foams and pellets from utensils, containers and packaging. By taking advantage of the different molecular interactions around tannic acids, our bioCap solution was able to remove virtually all of these different microplastic types."

Collaborating on sustainable solutions

The UBC method was developed in collaboration with Dr. Junling Guo, a professor at the Center of Biomass Materials and Nanointerfaces at Sichuan University in China. Marina Mehling (she/her), a PhD student at UBC's department of chemical and biological engineering, and Dr. Tianyu Guo (she/her), a postdoctoral researcher at the BioProducts Institute, also contributed to the work.

Read more at Science Daily

Possible seasonal climate patterns on early Mars

New observations of mud cracks made by the Curiosity rover show that high-frequency, wet-dry cycling occurred in early Martian surface environments, indicating that the red planet may have once seen seasonal weather patterns or even flash floods. The research was published today in Nature.

"These exciting observations of mature mud cracks are allowing us to fill in some of the missing history of water on Mars. How did Mars go from a warm, wet planet to the cold, dry place we know today? These mud cracks show us that transitional time, when liquid water was less abundant but still active on the Martian surface," said Nina Lanza, principal investigator of the ChemCam instrument onboard the Curiosity rover. "These features also point to the existence of wet-dry environments that on Earth are extremely conducive to the development of organic molecules and potentially life. Taken as a whole, these results a giving us a clearer picture of Mars as a habitable world."

The presence of long-term wet environments, such as evidence of ancient lakes on Mars, is well-documented, but far less is known about short-term climate fluctuations.

After years of exploring terrain largely composed of silicates, the rover entered a new area filled with sulfates, marking a major environment transition. In this new environment, the research team found a change in mud crack patterns, signifying a change in the way the surface would have dried. This indicates that water was still present on the surface of Mars episodically, meaning water could have been present for a time, evaporated, and repeated until polygons, or mud cracks, formed.

"A major focus of the Curiosity mission, and one of the main reasons for selecting Gale Crater, is to understand the transition of a 'warm and wet' ancient Mars to a 'cold and dry' Mars we see today," said Patrick Gasda of the Laboratory's Space Remote Sensing and Data Science group and coauthor of the paper. "The rover's drive from clay lakebed sediments to drier non-lakebed and sulfate-rich sediments is part of this transition."

On Earth, initial mud cracks in mud form a T-shaped pattern, but subsequent wetting and drying cycles cause the cracks to form more of a Y-shaped pattern, which is what Curiosity observed. Additionally, the rover found evidence that the mud cracks were only a few centimeters deep, which could mean that wet-dry cycles were seasonal, or may have even occurred more quickly, such as in a flash flood.

These findings could mean that Mars once had an Earth-like wet climate, with seasonal or short-term flooding, and that Mars may have been able to support life at some point.

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'Planting' rocks in farms, along with emissions reductions, could help meet key IPCC carbon removal goal

Farmers around the world could help the planet reach a key carbon removal goal set by the Intergovernmental Panel on Climate Change (IPCC) by mixing crushed volcanic rocks into their fields, a new study reports. The study also highlights wet, warm tropics as the most promising locations for this climate intervention strategy.

The study provides one of the first global estimates of the potential carbon dioxide drawdown from basalt application on agricultural fields worldwide. It was published in Earth's Future, AGU's journal for interdisciplinary research on the past, present and future of our planet and its inhabitants.

This type of climate intervention is called enhanced rock weathering. It takes advantage of the weathering process, which naturally sequesters carbon dioxide in carbonate minerals. The idea is simple: speed up weathering in a way that also benefits people. When used in parallel with emissions reductions, it can help slow the pace of climate change.

And it may be a safer bet than other carbon drawdown approaches, according to the study authors.

"Enhanced rock weathering poses fewer risks compared to other climate interventions," said S. Hun Baek, a climate scientist at Yale University who led the study. "It also provides some key benefits, like rejuvenating depleted soils and countering ocean acidification, that may make it more socially desirable."

The new study explores the potential of applying crushed basalt, a fast-weathering rock that forms as lava cools, to agricultural fields around the world and highlights which regions can most efficiently break down the rocks.

"There's tremendous potential here," said Noah Planavsky, a geochemist at Yale University who co-authored the study. "Although we still have things to learn from a basic science perspective, there is promise, and we need to focus on what we can do from market and finance perspectives."

A previous study used a separate method of calculating carbon dioxide removal to estimate carbon drawdown by the year 2050, but the researchers wanted to look beyond country borders and further into the future.

The researchers used a new biogeochemical model to simulate how applying crushed basalt to global croplands would draw down carbon dioxide, to test the sensitivity of enhanced rock weathering to climate and to pinpoint the areas where the method could be most effective.

The new model simulated enhanced rock weathering on 1,000 agricultural sites around the world under two emissions scenarios from 2006 to 2080. They found that in the 75-year study period, those agricultural sites would draw down 64 gigatons of carbon dioxide. Extrapolating that to all agricultural fields, representing the world's total potential application of this strategy, up to 217 gigatons of carbon could be sequestered in that time period.

"The latest IPCC report said we need to remove 100 to 1,000 gigatons of carbon by 2100 in addition to steeply reducing emissions to keep global temperature from rising more than one and a half degrees Celsius," said Baek. "Scaling up to global croplands, the estimates of carbon removal we found are roughly comparable to the lower end of that range needed to have a fighting chance of meeting those climate goals."

Because weathering progresses more quickly in hot and wet environments, enhanced rock weathering would work more quickly in tropical regions than higher latitudes, the study highlights. Farmers and companies looking to invest in carbon drawdown solutions make cost- and carbon-efficient choices by targeting basalt application in tropical fields.

The model revealed another promising result: Enhanced rock weathering works just as well, if not a little better, in warmer temperatures. Some other carbon drawdown approaches, such as those that rely on soil organic carbon storage, become less effective with continual warming.

"Enhanced rock weathering is surprisingly resilient to climate change," Baek said. "Our results show that it's relatively insensitive to climate change and works about the same under moderate and severe global warming scenarios. This gives us confidence in its potential as a long-term strategy."

Farmers already apply millions of tons of limestone (a calcium carbonate rock that can either be a carbon source or sink) to their fields to deliver nutrients and control soil acidity, so gradually changing the rock type could mean a smooth transition to implementing enhanced rock weathering at scale, Planavsky said.

Read more at Science Daily

Wildfires and farming activities may be top sources of air pollution linked to increased risk, cases of dementia

No amount of air pollution is good for the brain, but wildfires and the emissions resulting from agriculture and farming in particular may pose especially toxic threats to cognitive health, according to new research from the University of Michigan.

Increasingly, evidence shows exposure to air pollution makes the brain susceptible to dementia. And now the findings of Boya Zhang and Sara Adar, environmental epidemiology researchers in U-M's School of Public Health, point to a strong likelihood that agriculture and wildfires, with their release of a range of harmful emissions at high concentrations, need to be more closely studied and monitored for their risks to public health, specifically dementia.

"We saw in our research that all airborne particles increased the risk of dementia but those generated by agricultural settings and wildfires seemed to be especially toxic for the brain," said Adar, associate chair of the Department of Epidemiology in the School of Public Health. She currently leads several large cohort studies on the impacts of exposures on cognitive aging and dementia.

"Our findings indicate that lowering levels of particulate matter air pollution, even in a relatively clean country like the United States, may reduce the number of people developing dementia in late life," Adar said.

Adar and Zhang's paper, "Comparison of Particulate Air Pollution From Different Emission Sources and Incident Dementia in the U.S.," appears today in the Journal of the American Medical Association's Internal Medicine.

Zhang, a research fellow who focuses on the effects of air pollution on cardiopulmonary disease and cognitive aging, said: "This work suggests that particulate matter air pollution from agriculture and wildfires might be more neurotoxic compared with other sources. However, more research is needed to confirm these effects, especially for these two sources which have received less attention in prior research."

"Given that the development of dementia could take a long time, this study mainly aimed to provide evidence for policymakers to reduce exposures to these sources of emissions," Zhang said.

The findings come as unusually poor air quality is regularly triggering alerts in the U.S. The alerts are aimed at protecting the public from the unseen, swirling mix of microscopic toxins in air pollution, specifically fine particulate matter or PM2.5. It is one of the most concerning elements of air pollution. At less than 2.5 microns in size, PM2.5 is less than the width of a human hair. Because it's so small, it can enter the brain through the nose directly or cross the blood-brain barrier in other ways. PM2.5 is also known to affect the lungs, heart, and in emerging research, the brain and cognitive function.

"These findings are quite timely given the increasing frequency of wildfire smoke in our

communities," Adar said. "Our data suggest that in addition to some of the more obvious health impacts of wildfire smoke like irritation to our throats and eyes along with breathing difficulties, high smoke days might also be taking a toll on our brains."

The record number of air quality alerts in the U.S. this year are due in large part to smoke from wildfires burning in Canada since May. The effect of wildfire is not new in the U.S., especially given the fires in the western part of the country.

Adar, a long-time environmental epidemiologist, said that wildfire smoke is becoming a more widespread stressor with many cities experiencing 30-plus days each year impacted by smoke. Given the extremely high levels of exposure to the public, wildfires are thought to contribute up to 25% of fine particulate matter exposures over a year across the U.S. and as much as 50% in some western regions of the country, Adar said.

"While individual wildfires may be short-lived, these events are becoming more frequent in our communities due to warmer temperatures, drier conditions, and longer fire seasons. As we've seen, wildfire smoke can also travel very far distances," Adar said.

Their findings are based on research into the development of dementia among nearly 30,000 adults from across the U.S. over an 18-year period. The data comes from the Health and Retirement Study, a nationally-representative collection of cohorts of older adults who have been followed since 1992. Pollution estimates in Adar and Zhang's study were based on home addresses of participants. Participants have been interviewed biennially about their cognition, overall health, and health behaviors until death or loss of contact for the survey.

They observed that higher levels of particulate matter air pollution, especially from agriculture and wildfires, were associated with greater risks of dementia. The findings could not be explained by other factors such as individual, neighborhood, socioeconomic status, occupation, or hometown or region of the country.

"With the knowledge of which sources are more toxic than others, it may be possible to design interventions for specific sources as a more effective way to decrease the burden of dementia," Zhang said.

Dementia is currently the seventh leading cause of death and one of the major causes of disability and dependency for older people, according to the World Health Organization.

The research specifically sought to test the hypothesis that a variation in emission sources could explain which are most toxic, but measuring the emissions with their distinct physical and chemical characteristics is challenging.

Past studies analyzing exposures to source specific fine particulate matter meant researchers mainly investigated relationships with the total mass of fine particulate matter in the air.

"In our study, we used a sophisticated prediction model that includes information about the chemical transformations and dispersion of pollution from different sources to estimate the levels of source-specific particulate matter air pollution at participants' residential addresses," Zhang said. "This approach is beneficial because it not only accounts for pollution directly emitted by a source but also pollution generated through reactions with other chemicals in the air."

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How orangutans respond to novelty in the wild

Humans like to discover. Presented with something we've never seen before, most of us will be compelled to explore and learn more about it. The same can't exactly be said for our closest living relatives -- the great apes. Although decades of studies have shown that captive chimpanzees, gorillas, and orangutans will eagerly explore unfamiliar objects in a laboratory, great apes have rarely been observed in these encounters in the wild. As such, almost nothing is known about how great apes respond to novelty in the natural habitats in which they evolved. Now, a team from the Max Planck Institute of Animal Behavior (MPI-AB) has succeeded in measuring the behavior of wild orangutans in their first encounter with an unfamiliar object. The experiments, conducted in an Indonesian rainforest, uncovered a mix of social, environmental, and age factors that made orangutans more likely to explore. Published in Scientific Reports, the study reveals the conditions that spark curiosity in orangutans, and sheds light on how our own curious natures might have evolved.

The team studied orangutans at a long-term monitoring site, Suaq Balimbing, in Sumatra. Orangutans at the site have been habituated over decades to the presence of humans, thus offering scientists a rare opportunity to observe wild great apes at close range. Caroline Schuppli, director of the Suaq Project and the study's first author, became interested in how wild orangutans would react when presented with something unfamiliar.

"Curiosity is a trait that has driven the exceptional ability of humans to learn and innovate," says Schuppli, a group leader at MPI-AB. "If we want to know how the trait evolved in us, we have to study it in our closest living relatives."

Curiosity, which describes an individual's motivation to learn about the unknown, has been studied before in great apes; however, due to the logistical difficulties of studying wild animals, almost all tests have occurred in captivity. "We know that apes are very curious to explore when they are in the safe and controlled conditions of a zoo," says Schuppli. "But these results tell us little about what really triggered or suppressed curiosity over our evolutionary history."

About ten years ago, Schuppli and collaborators first attempted to assess curiosity in wild orangutans with an experiment inspired by captive studies. They roamed Suaq, peppering the forest with foreign objects for the orangutans to find: a bright red flag; plastic flowers and fruits; a stuffed toy. The results were stark. "They hardly ever came near any of the items," she remembers. "You could see them making huge circles in the forest to avoid the experiment."

Schuppli realized that testing orangutans' reaction to novelty in nature would require reimagining the past paradigm. "The challenge was figuring out how to entice them with something that was novel, but also familiar enough not to scare them off," she says. Over the years Schuppli perfected just such an object: a piece of tree trunk with a natural hole filled with local forest honey. The tree hole and food were familiar, but deploying these in an unusual way represented a novel foraging situation. With a team of local and international scientists, Schuppli hoisted the experimental log into trees about 10 meters from orangutans -- and watched what happened.

During the trials, the orangutans spent on average 30 minutes in the vicinity of the novel log. During this time, they explored the novel log by intensively observing it over extended periods of time and approaching it closely. Overall, however, orangutans rarely touched the branch directly; and when they did, they often used a tool, such as a stick to do so. "The orangutans were pretty cautious," says Tri Rahmaeti, a team member from Universitas Nasional in Indonesia and co-author on the study. "The honey reward could have easily been scooped out of the log using a finger, but they still preferred to use a tool so they didn't have to make physical contact."

But there were significant differences in the behaviors. Using statistical techniques, the team uncovered traits of individuals and features in the environment that amplified exploration. Young orangutans were far more likely than adults to observe and approach. And, orangutans were more likely to approach the log if they saw another individual heading that way too. The habitat also seemed to play a role: in areas with abundant food, orangutans observed more but approached less.

Says Schuppli: "On the one hand, the results confirmed our hunch that orangutans in the wild are not that keen to explore new objects. This could be because in nature, orangutans live very long lives in stable habitats where novelty is rare. So, the potential risk of approaching something unknown doesn't outweigh the potential reward."

"On the other hand, the experiment showed that there is flexibility in the behavior. Orangutans have the potential to be curious about novelty in nature, but only under certain conditions. And by experimentally testing this in a wild population, we pinned down the conditions."

Of these conditions, Schuppli finds the social factor most illuminating. "Orangutans are the least social of all great apes, and yet we find that the presence of association partners increases their curiosity," she says.

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Hundred-year storms? That's how long they last on Saturn

The largest storm in the solar system, a 10,000-mile-wide anticyclone called the Great Red Spot, has decorated Jupiter's surface for hundreds of years.

A new study now shows that Saturn -- though much blander and less colorful than Jupiter -- also has long-lasting megastorms with impacts deep in the atmosphere that persist for centuries.

The study was conducted by astronomers from the University of California, Berkeley, and the University of Michigan, Ann Arbor, who looked at radio emissions from the planet, which come from below the surface, and found long-term disruptions in the distribution of ammonia gas.

The study was published today (Aug. 11) in the journal Science Advances.

Megastorms occur approximately every 20 to 30 years on Saturn and are similar to hurricanes on Earth, although significantly larger. But unlike Earth's hurricanes, no one knows what causes megastorms in Saturn's atmosphere, which is composed mainly of hydrogen and helium with traces of methane, water and ammonia.

"Understanding the mechanisms of the largest storms in the solar system puts the theory of hurricanes into a broader cosmic context, challenging our current knowledge and pushing the boundaries of terrestrial meteorology," said lead author Cheng Li, a former 51 Peg b Fellow at UC Berkeley who is now an assistant professor at the University of Michigan.

Imke de Pater, a UC Berkeley professor emerita of astronomy and of earth and planetary sciences, has been studying gas giants for over four decades to better understand their composition and what makes them unique, employing the Karl G. Jansky Very Large Array in New Mexico to probe the radio emissions from deep inside the planet.

"At radio wavelengths, we probe below the visible cloud layers on giant planets. Since chemical reactions and dynamics will alter the composition of a planet's atmosphere, observations below these cloud layers are required to constrain the planet's true atmospheric composition, a key parameter for planet formation models," she said. "Radio observations help characterize dynamical, physical and chemical processes including heat transport, cloud formation and convection in the atmospheres of giant planets on both global and local scales."

As reported in the new study, de Pater, Li and UC Berkeley graduate student Chris Moeckel found something surprising in the radio emissions from the planet: anomalies in the concentration of ammonia gas in the atmosphere, which they connected to the past occurrences of megastorms in the planet's northern hemisphere.

According to the team, the concentration of ammonia is lower at midaltitudes, just below the uppermost ammonia-ice cloud layer, but has become enriched at lower altitudes, 100 to 200 kilometers deeper in the atmosphere. They believe that the ammonia is being transported from the upper to the lower atmosphere via the processes of precipitation and reevaporation. What's more, that effect can last for hundreds of years.

The study further revealed that although both Saturn and Jupiter are made of hydrogen gas, the two gas giants are remarkably dissimilar. While Jupiter does have tropospheric anomalies, they have been tied to its zones (whitish bands) and belts (darkish bands) and are not caused by storms like they are on Saturn. The considerable difference between these neighboring gas giants is challenging what scientists know about the formation of megastorms on gas giants and other planets and may inform how they're found and studied on exoplanets in the future.

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Even treated wastewater affects our rivers

Effluents from wastewater treatment plants have a dual effect: Some species disappear, while others benefit. Especially certain insect orders, such as stonefly and caddisfly larvae, are decimated. Certain worms and crustaceans, by contrast, can increase in number. A team from Goethe University Frankfurt led by Daniel Enns and Dr. Jonas Jourdan has corroborated this in a comprehensive study, which has now been published in the journal Water Research. They examined 170 wastewater treatment plants in Hesse in relation to species composition.

Wastewater treatment plants are an indispensable part of our modern infrastructure; they have made a significant contribution to improving the quality of our surface waters. However, their ability to completely remove what are known as micropollutants from wastewater is mostly limited. These substances include, for example, active ingredients from pharmaceuticals and personal care products, pesticides and other synthetic substances enter waterbodies via the treated wastewater, placing an additional burden on rivers and streams. This exacerbates the challenges faced by already vulnerable insect communities and aquatic fauna. Previous studies -- which have primarily focused on single wastewater treatment plants -- have already shown that invertebrate communities downstream of such effluents are generally dominated by pollution-tolerant taxa.

Until now, however, it was unclear how ubiquitous these changes are. That is why a team of biologists from Goethe University Frankfurt has now studied extensively how wastewater from 170 wastewater treatment plants in Hesse has an impact on the species composition of invertebrates. This has prompted a change in the common conception that human-induced stressors reduce the number of species in a habitat and thus their diversity: Rather, the findings indicate that a shift in species composition can be observed. The researchers were able to identify significant shifts in the composition of the species community between sites located upstream and downstream of wastewater treatment plants. Some species were particularly affected by effluents from wastewater treatment plants -- such as stonefly and caddisfly larvae, which disappear entirely in some places. Other taxa, such as certain worms and crustaceans, by contrast, benefit and are found in greater numbers. This change can be observed especially in streams and smaller rivers. Overall, wastewater treatment plants alter conditions downstream to the advantage of pollution-tolerant taxa and to the disadvantage of sensitive ones.

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Fat burning during exercise varies widely between individuals

The best heart rate for burning fat differs for each individual and often does not align with the "fat burning zone" on commercial exercise machines, Icahn School of Medicine at Mount Sinai researchers report.

Instead, the researchers said, clinical exercise testing -- a diagnostic procedure to measure a person's physiological response to exercise -- may be a more useful tool to help individuals achieve intended fat loss goals. The study, which used a machine learning-based modeling approach, was published online today in Nutrition, Metabolism and Cardiovascular Disease.

"People with a goal of weight or fat loss may be interested in exercising at the intensity which allows for the maximal rate of fat burning. Most commercial exercise machines offer a 'fat-burning zone' option, depending upon age, sex, and heart rate," says lead author Hannah Kittrell, MS, RD, CDN, a PhD candidate at Icahn Mount Sinai in the Augmented Intelligence in Medicine and Science laboratory. "However, the typically recommended fat-burning zone has not been validated, thus individuals may be exercising at intensities that are not aligned with their personalized weight loss goals."

Ms. Kittrell is also Director of the Mount Sinai Physiolab, a clinical body composition and exercise physiology laboratory at Mount Sinai Morningside.

The term FATmax is sometimes used to represent the exercise intensity and associated heart rate at which the body reaches its highest fat-burning rate during aerobic exercise. At this point, fat is a significant fuel source and therefore this intensity may be of interest to those seeking to optimize fat loss during workouts.

As part of the study, the researchers compared heart rate at FATmax, as measured during a clinical exercise test, to predicted heart rate at percentages of maximal effort within the typically recommended "fat-burning zone." In a sample of 26 individuals, the researchers found that there was poor agreement between measured and predicted heart rate, with a mean difference of 23 beats per minute between the two measures. This suggests that general recommendations for a "fat-burning zone" may not provide accurate guidance.

Next, the researchers plan to study whether individuals who receive a more personalized exercise prescription demonstrate more weight and fat loss, as well as improvement of metabolic health markers that identify health risks like type 2 diabetes, obesity, and heart disease.

"We hope that this work will inspire more individuals and trainers to utilize clinical exercise testing to prescribe personalized exercise routines tailored to fat loss. It also emphasizes the role that data-driven approaches can have toward precision exercise," says senior author Girish Nadkarni, MD, MPH, Irene and Dr. Arthur M. Fishberg Professor of Medicine at Icahn Mount Sinai, Director of The Charles Bronfman Institute of Personalized Medicine, and System Chief, Division of Data-Driven and Digital Medicine, Department of Medicine.

The paper is titled "Discrepancy between predicted and measured exercise intensity for eliciting the maximal rate of lipid oxidation."

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Researchers identify 135 new melanin genes responsible for pigmentation

The skin, hair and eye color of more than eight billion humans is determined by the light-absorbing pigment known as melanin. An article recently published in the journal Science features research from Vivek Bajpai, Ph.D., lead author and an assistant professor in the School of Sustainable Chemical, Biological and Materials Engineering at the University of Oklahoma, and collaborators from Stanford University. Their research has identified 135 new genes associated with pigmentation.

Melanin is produced within special structures called melanosomes. Melanosomes are found inside melanin-producing pigment cells called melanocytes. Although all humans have the same number of melanocytes, the amount of melanin they produce differs and gives rise to the variation in human skin color.

"To understand what actually causes different amounts of melanin to be produced, we used a technology called CRISPR-Cas9 to genetically engineer cells," Bajpai said. "Using CRISPR, we systematically removed more than 20,000 genes from hundreds of millions of melanocytes and observed the impact on melanin production."

To identify which genes influence melanin production, cells that lost melanin during the gene removal process needed to be separated from millions of other cells that did not. Using in vitro cell cultures, Bajpai developed a novel method to achieve this goal that detects and quantifies the melanin-producing activity of melanocytes. By passing light through the melanocytes, he could record if the light was either absorbed or scattered by the melanin inside.

"If there are a lot of melanin-producing melanosomes, the light will scatter much more than in cells with little melanin," Bajpai said. "Using a process called side-scatter of flow cytometry, we were able to separate cells with more or less melanin. These separated cells were then analyzed to determine the identity of melanin-modifying genes. We identified both new and previously known genes that play important roles in regulating melanin production in humans."

The researchers found 169 functionally diverse genes that impacted melanin production. Of those, 135 were not previously associated with pigmentation. They further identified the function of two newly discovered genes: KLF6 and COMMD3. The DNA-binding protein KLF6 led to a loss of melanin production in humans and animals, confirming the role KLF6 plays in melanin production in other species as well. The COMMD3 protein regulated melanin synthesis by controlling the acidity of melanosomes.

Historically, darker pigmentation has been needed to protect against ultraviolet radiation in areas closer to the equator and for people who spend hours in direct sunlight. As humans moved into areas with less direct sunlight or fewer hours of daylight overall, less melanin was needed. Over time, this resulted in melanosomes that produced less melanin, thus absorbing more sunlight.

"By understanding what regulates melanin, we can help protect lighter-skinned people from melanoma, or skin cancer," Bajpai said. "By targeting these new melanin genes, we could also develop melanin-modifying drugs for vitiligo and other pigmentation diseases."

The technological processes developed and used by the research team could also be applied to identify genes that regulate melanin production in fungi and bacteria. Melanin production in fungi and bacteria enables them to be more pathogenic to humans or crops. Researchers could develop effective interventions against these microbes and their diseases by discovering and targeting such melanin-producing genes.

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