Hibernating corals and the microbiomes that sustain them

As winter approaches, many species of animals -- from bears and squirrels to parasitic wasps and a few lucky humans -- hunker down for some needed rest. The northern star coral (Astrangia poculata)also enters a hibernating state of dormancy, or quiescence, during this time. But what happens to its microbiome while it's sleeping?

A study led by University of California, Davis, Assistant Professor Anya Brown found that microbial communities shift while this coral enters dormancy, providing it an important seasonal reset. The work may carry implications for coral in warmer waters struggling with climate change and other environmental issues.

"Dormancy, at its most basic, is a response to an environmental stressor -- in this case, cold stress," said Brown, who is part of the UC Davis Bodega Marine Laboratory in the Department of Evolution and Ecology. "If we understand more about this recovery period, it might help us understand what microbes may be responsible for recovering coral in warmer tropical systems."

The study, published in the journal Applied and Environmental Microbiology with scientists from Woods Hole Oceanographic Institution, or WHOI, and Roger Williams University, is the first to demonstrate a persistent microbial community shift with dormancy in a marine animal.

"This study shows that microbes respond to stress and recover in a predictable pattern," said co-author Amy Apprill, an associate scientist at WHOI. "It's foundational knowledge that may help us develop probiotics or other microbial treatments for stressed tropical corals."

While you were sleeping

From October 2020 through March 2021, researchers dove 60 feet down into cold, nearly 40 degrees Fahrenheit water to collect 10 distinct colonies of the coral A. poculata from a dock in Woods Hole, Massachusetts. This coral is found in Atlantic waters extending from the Gulf of Mexico to Massachusetts. As water temperatures cool, the coral retracts its tentacles, stops eating or responding to touch, and goes dormant.

The scientists characterized the microbiomes of the wild coral before, during and after dormancy. They found that while the coral "sleeps," its microbiome sheds nutrient-loving and pathogen-associated microbes, while increasing microbes that may contribute nitrogen while the coral is no longer eating. The scientists found that this restructuring helps the corals maintain their microbial community structure.

"We have long hypothesized that Astrangia's seasonal dormancy allows the coral microbiome to reset and restructure," said co-author Koty Sharp, associate professor at Roger Williams University. "Our research found evidence for a shuffling during that dormant period that may help us identify microbial associates that are key to coral health and recovery from disturbance."

Why does coral wake up?

With this study, a marine species -- the coral A. poculata -- now joins bears, squirrels, crickets and others on the list of animals found to have microbiomes that shift while they are dormant. For example, the ground squirrel's gut microbiome plays an important role in nitrogen recycling while the squirrel fasts during hibernation.

"This work opens a lot of questions," Brown said. "A big one is: Why does the coral 'wake up' in the early spring? This study suggests that key microbial groups may play an important role in triggering the onset of or emergence from this coral's dormancy and the regulation of its microbiome."

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Green tea extract may harm liver in people with certain genetic variations

Long-term use of high-dose green tea extract may provide some protection against cancer, cardiovascular disease, obesity and type 2 diabetes, but it also may create liver damage in a small minority of the population.

Who is at risk? Research from Rutgers, published in The Journal of Dietary Supplements, provides the first solid clue: two genetic variants that predict some of the risk.

"Learning to predict who will suffer liver damage is potentially important because there's growing evidence that high-dose green tea extract may have significant health benefits for those who can safely take it," said Hamed Samavat, senior author of the study and an assistant professor of nutrition sciences at the Rutgers School of Health Professions.

Using data from the Minnesota Green Tea Trial, a large study of green tea's effect on breast cancer, the research team investigated whether people with certain genetic variations were more likely than others to show signs of liver stress after a year of ingesting 843 milligrams per day of the predominant antioxidant in green tea, a catechin called epigallocatechin gallate (EGCG).

Researchers led by Laura Acosta, then a doctoral student, now a graduate, selected two genetic variations in question because each controls the synthesis of an enzyme that breaks EGCG down. They selected the Minnesota Green Tea Trial because it was a large, well-designed study of a unique population. The year-long, placebo-controlled trial included more than 1,000 postmenopausal women and collected data at 3, 6, 9 and 12 months.

An analysis by researchers showed that early signs of liver damage were somewhat more common than normal in women with one variation in the catechol-O-methyltransferase (COMT) genotype and strongly predicted by a variation in the uridine 5'-diphospho-glucuronosyltransferase 1A4 (UGT1A4) genotype.

On average, participants with the high-risk UGT1A4 genotype saw the enzyme that indicates liver stress go up nearly 80 percent after nine months of consuming the green tea supplement, while those with low-risk genotypes saw the same enzyme go up 30 percent.

"We're still a long way from being able to predict who can safely take high-dose green tea extract," said Samavat, who noted the risk of liver toxicity is only associated with high levels of green tea supplements and not with drinking green tea or even taking lower doses of green tea extract. "Variations in this one genotype don't completely explain the variations in liver enzyme changes among study participants. The full explanation probably includes a number of different genetic variations and probably a number of non-genetic factors."

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Astrophysicists hunt for second-closest supermassive black hole

Two astrophysicists at the Center for Astrophysics | Harvard & Smithsonian have suggested a way to observe what could be the second-closest supermassive black hole to Earth: a behemoth 3 million times the mass of the Sun, hosted by the dwarf galaxy Leo I.

The supermassive black hole, labeled Leo I*, was first proposed by an independent team of astronomers in late 2021. The team noticed stars picking up speed as they approached the center of the galaxy -- evidence for a black hole -- but directly imaging emission from the black hole was not possible.

Now, CfA astrophysicists Fabio Pacucci and Avi Loeb suggest a new way to verify the supermassive black hole's existence; their work is described in a study published today in the Astrophysical Journal Letters.

"Black holes are very elusive objects, and sometimes they enjoy playing hide-and-seek with us," says Fabio Pacucci, lead author of the ApJ Letters study. "Rays of light cannot escape their event horizons, but the environment around them can be extremely bright -- if enough material falls into their gravitational well. But if a black hole is not accreting mass, instead, it emits no light and becomes impossible to find with our telescopes."

This is the challenge with Leo I -- a dwarf galaxy so devoid of gas available to accrete that it is often described as a "fossil." So, shall we relinquish any hope of observing it? Perhaps not, the astronomers say.

"In our study, we suggested that a small amount of mass lost from stars wandering around the black hole could provide the accretion rate needed to observe it," Pacucci explains. "Old stars become very big and red -- we call them red giant stars. Red giants typically have strong winds that carry a fraction of their mass to the environment. The space around Leo I* seems to contain enough of these ancient stars to make it observable."

"Observing Leo I* could be groundbreaking," says Avi Loeb, the co-author of the study. "It would be the second-closest supermassive black hole after the one at the center of our galaxy, with a very similar mass but hosted by a galaxy that is a thousand times less massive than the Milky Way. This fact challenges everything we know about how galaxies and their central supermassive black holes co-evolve. How did such an oversized baby end up being born from a slim parent?"

Decades of studies show that most massive galaxies host a supermassive black hole at their center, and the mass of the black hole is a tenth of a percent of the total mass of the spheroid of stars surrounding it.

"In the case of Leo I," Loeb continues, "we would expect a much smaller black hole. Instead, Leo I appears to contain a black hole a few million times the mass of the Sun, similar to that hosted by the Milky Way. This is exciting because science usually advances the most when the unexpected happens."

So, when can we expect an image of the black hole?

"We are not there yet," Pacucci says.

The team has obtained telescope time on the space-borne Chandra X-ray Observatory and the Very Large Array radio telescope in New Mexico and is currently analyzing the new data.

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Old-growth trees more drought tolerant than younger ones, providing a buffer against climate change

A new analysis of more than 20,000 trees on five continents shows that old-growth trees are more drought tolerant than younger trees in the forest canopy and may be better able to withstand future climate extremes.

The findings highlight the importance of preserving the world's remaining old-growth forests, which are biodiversity strongholds that store vast amounts of planet-warming carbon, according to University of Michigan forest ecologist Tsun Fung (Tom) Au, a postdoctoral fellow at the Institute for Global Change Biology.

"The number of old-growth forests on the planet is declining, while drought is predicted to be more frequent and more intense in the future," said Au, lead author of the study published online Dec. 1 in the journal Nature Climate Change.

"Given their high resistance to drought and their exceptional carbon storage capacity, conservation of older trees in the upper canopy should be the top priority from a climate mitigation perspective."

The researchers also found that younger trees in the upper canopy -- if they manage to survive drought -- showed greater resilience, defined as the ability to return to pre-drought growth rates.

While deforestation, selective logging and other threats have led to the global decline of old-growth forests, subsequent reforestation -- either through natural succession or through tree planting -- has led to forests dominated by increasingly younger trees.

For example, the area covered by younger trees (<140 years old) in the upper canopy layer of temperate forests worldwide already far exceeds the area covered by older trees. As forest demographics continue to shift, younger trees are expected to play an increasingly important role in carbon sequestration and ecosystem functioning.

"Our findings -- that older trees in the upper canopy are more drought tolerant, while younger trees in the upper canopy are more drought resilient -- have important implications for future carbon storage in forests," Au said.

"These results imply that in the short term, drought's impact on forests may be severe due to the prevalence of younger trees and their greater sensitivity to drought. But in the long run, those younger trees have a greater ability to recover from drought, which could be beneficial to the carbon stock."

Those implications will require further study, according to Au and colleagues, given that reforestation has been identified by the Intergovernmental Panel on Climate Change as a potential nature-based solution to help mitigate climate change.

The Sharm el-Sheikh Implementation Plan published during the 2022 United Nations Climate Change Conference in Egypt (COP27) also reaffirmed the importance of maintaining intact forest cover and associated carbon storage as a social and environmental safeguard.

"These findings have implications for how we manage our forests. Historically, we have managed forests to promote tree species that have the best wood quality," said Indiana University's Justin Maxwell, a senior author of the study.

"Our findings suggest that managing forests for their ability to store carbon and to be resilient to drought could be an important tool in responding to climate change, and thinking about the age of the forest is an important aspect of how the forest will respond to drought."

The researchers used long-term tree-ring data from the International Tree-Ring Data Bank to analyze the growth response of 21,964 trees from 119 drought-sensitive species, during and after droughts of the past century.

They focused on trees in the uppermost canopy. The forest canopy is a multilayered, structurally complex and ecologically important zone formed by mature, overlapping tree crowns.

The upper canopy trees were separated into three age groups -- young, intermediate and old -- and the researchers examined how age influenced drought response for different species of hardwoods and conifers.

They found that young hardwoods in the upper canopy experienced a 28% growth reduction during drought, compared to a 21% growth reduction for old hardwoods. The 7% difference between young and old hardwoods grew to 17% during extreme drought.

While those age-related differences may appear fairly minor, when applied at the global scale they could have "huge impacts" on regional carbon storage and the global carbon budget, according to the study authors. That's especially true in temperate forests that are among the largest carbon sinks worldwide.

In the study, age-related drought-response differences in conifers were smaller than in hardwoods, likely because needle-bearing trees tend to inhabit more arid environments, the researchers say.

The current study was part of Au's doctoral dissertation at Indiana University, and he continued the work after joining U-M's Institute for Global Change Biology, which is based at the School for Environment and Sustainability.

The new study is a synthesis that represents the net effects of thousands of trees in diverse forests across five continents, rather than focusing on single forest types. In addition, the new study is unique in its focus on trees in the upper forest canopy, which reduces the confounding effects of tree height and size, according to the authors.

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Positively charged nanomaterials treat obesity anywhere you want

Researchers have long been working on how to treat obesity, a serious condition that can lead to hypertension, diabetes, chronic inflammation, and cardiovascular diseases. Studies have also revealed a strong correlation of obesity and cancer -- recent data show that smoking, drinking alcohol, and obesity are the biggest contributors to cancer worldwide.

The development of fat cells, which are produced from a tiny fibroblast-like progenitor, not only activates the fat cells' specific genes but also grows them by storing more lipids (adipocytes and adipose tissue). In fact, lipid storage is the defining function of a fat cell. But the storage of too much lipid can make fat cells unhealthy and lead to obesity.

Challenges in targeting fat cells

The ability to target fat cells and safely uncouple unhealthy fat formation from healthy fat metabolism would be the answer to many peoples' prayers. A major challenge in obesity treatment is that fat tissue, which is not continuous in the body but is found piece by piece in "depots," has been difficult to target in a depot-specific manner, pinpointed at the exact location.

There are two main kinds of fat: visceral fat, internal tissues that surround the stomach, liver, and intestines, and subcutaneous fat, found under the skin anywhere in the body. Visceral fat produces potbellies; subcutaneous fat can create chin jowls, arm fat, etc. To date, there has been no way to specifically treat visceral adipose tissue. And current treatments for subcutaneous fat like liposuction are invasive and destructive.

New studies use cationic nanonmaterials to target fat

Two new studies from researchers at Columbia Engineering and Columbia University Irving Medical Center (CUIMC) may have the answer to targeting fat cells depot-specifically and healthily. The papers demonstrate a new method to treat obesity by using cationic nanomaterials that can target specific areas of fat and inhibit the unhealthy storage of enlarged fat cells. The materials remodel fat rather than destroying it, as, for example, liposuction does. The first paper, published today by Nature Nanotechnology, focuses on visceral adiposity, or belly fat. The second paper, published online November 28 by Biomaterials, focuses on fat underneath the skin as well as chronic inflammation associated with obesity.

The team of researchers, led by Li Qiang, associate professor of pathology and cell biology at CUIMC, and Kam Leong, Samuel Y. Sheng Professor of Biomedical Engineeringand of systems biology at CUIMC, recognized that adipose tissue contains large amounts of negatively charged extracellular matrix (ECM) to hold fat cells. They thought that this negatively charged ECM network might provide a highway system of sorts for positively charged molecules. So they took a positively charged nanomaterial, PAMAM generation 3 (P-G3), and injected it into obese mice. The P-G3 quickly spread throughout the tissue and the team was excited that their method to specifically target visceral fat worked.

Unexpected results

And then something intriguing happened: P-G3 shut off the lipid storage program in fat cells and the mice lost weight. This was totally unexpected, given the well-established function of P-G3 in neutralizing negatively charged pathogens, such as DNA/RNA cell debris, to alleviate inflammation.

"Our approach is unique -- It departs from the pharmacological or surgical approaches," says Qiang, who specializes in obesity and adipocyte biology. "We used cationic charge to rejuvenate healthy fat cells, a technique no one has ever used to treat obesity. I think this novel strategy will open the door to healthier and safer reduction of fat."

P-G3 helps new fat cell formation and also inhibits the unhealthy lipid storage of enlarged fat cells

In these two studies, the researchers discovered that the cationic material, P-G3, could do an intriguing thing to fat cells -- while it helped new fat cell formation, it also uncoupled lipid storage from the housekeeping functions of fat cells. And because it inhibits the unhealthy lipid storage of enlarged fat cells, the mice had more metabolically healthy, young, small fat cells like those found in newborns and athletes. The researchers found that this uncoupling function of P-G3 also holds true in human fat biopsies, signifying the potential of translation in humans.

"With P-G3, fat cells can still be fat cells, but they can't grow up," said Leong, a pioneer in using polycation to scavenge pathogens. "Our studies highlight an unexpected strategy to treat visceral adiposity and suggest a new direction of exploring cationic nanomaterials for treating metabolic diseases."

New applications for drug delivery, gene therapy, and aesthetics

Now that they can selectively target visceral fat, Leong and Qiang envision several applications. The Biomaterials study demonstrates a simple approach that could be used for aesthetic purposes; like Botox, P-G3 can be locally injected into a specific, subcutaneous fat depot. The investigators, who have patents pending, are now engineering P-G3 into various derivatives to improve the efficacy, safety, and depot specificity.

What the researchers are particularly excited about is developing P-G3 into a platform that can deliver drugs and gene therapies specifically to a given fat depot. This may repurpose many drugs from systemic safety concerns, such as Thiazolidinediones (TZDs), a potent but unsafe drug that is a strong modulator of fat and used to treat type 2 diabetes -- but it has been linked to heart failure and banned in several countries.

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Early life experiences can have long-lasting impact on genes

Early life experiences can impact the activity of our genes much later on and even affect longevity, finds a new study in fruit flies led by UCL researchers.

In the study published in Nature Aging, the scientists report that gene expression 'memory' can persist across the lifespan, and may present a novel target for improving late-life health.

Lead author Dr Nazif Alic (UCL Institute of Healthy Ageing, UCL Biosciences) said: "Health in old age partially depends on what a person experienced in their youth or even in the womb. Here, we have identified one way in which this happens, as changes in gene expression in youth can form a 'memory' that impacts health more than half a lifetime later."

The scientists were building on their previous research in which they found that fruit flies fed a high-sugar diet early in life lived shorter lives, even after their diets were improved in adulthood. Here, they uncover the mechanism likely explaining the finding.

In their previous study, the researchers found that a high-sugar diet inhibited a transcription factor called dFOXO, which is involved in glucose metabolism and is known from multiple studies to affect longevity, so they now sought to enact the opposite effect by directly increasing the activity of dFOXO. Transcription factors are proteins that regulate transcription, or copying, of information from DNA into messenger RNA, which is the first and key step in gene expression. For this study, the researchers activated dFOXO by increasing its levels in female fruit flies during the first three weeks of the fly's adulthood.

They found that these early-life experiences caused changes to chromatin -- a mixture of DNA and proteins that can be seen as the 'packaging' of DNA -- that persisted and resulted in genes being expressed differently late in life. This counteracted some changes that would be expected as part of the normal ageing process, eventually improving health in late life and impacting the fruit flies' lifespan more than a month (half a fruit fly lifetime) later.

The researchers say their findings could lead to ways to impact late-life health in people as well.

Dr Alic said: "What happens early on in an animal or person's life can affect what their genes do late in life, for better or for worse. It may be that a poor diet early in life, for example, could impact our metabolism later in life by tweaking how our genes are expressed, even after substantial dietary changes over the years -- but fortunately, it may well be possible to reverse this.

"Now that we know how gene expression memory can persist across the lifespan to affect gene activity, we may be able to develop ways to counteract these changes later in life to preserve health and enable people to stay healthy for longer."

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Small asteroids are probably young

The Hayabusa2 spacecraft was developed in order to study the history of the asteroid Ryugu, and collected samples and returned them to earth for laboratory analysis. The project participants are Dr. Martin Jutzi and Dr. Sabina Raducan, both from the Physical Institute of the University of Bern, Department for Space Research and Planetology (WP), and are members of the National Center of Competence in Research (NCCR) PlanetS. Under their leadership, in a study which has recently been published in Nature Communications, the team has presented new findings on the formation and development of asteroids.

Rules on the development of craters help with dating asteroids

To explore the characteristics of asteroids, during the space mission Hayabusa2, a Small Carry-on Impactor was fired at the surface of the asteroid Ryugu. "The crater made by the impact was far larger than expected. We therefore tried to reproduce the results of the impact on Ryugu with the use of simulations, to ascertain the kind of characteristics the material is required to have on the surface of the asteroid," explains Martin Jutzi.

The nature and the size of an impact crater on an asteroid are influenced by various factors. Firstly, by the specific characteristics of the projectile, and secondly, by the characteristics of the asteroid -- its strength or gravity, for example. "The size and nature of the crater resulting from the impact can lead to a direct diagnosis of the material characteristics and the near-surface structure of the asteroid," explains Jutzi. The study of the crater formation process therefore has important implications for the understanding of the geological and geophysical development of asteroids.

"So far, the way in which the formation of craters works at low gravity has largely remained unexplored. This is because the conditions of the impact cannot be simulated in laboratory experiments on Earth," explains Sabina Raducan, who is managing the project together with Martin Jutzi. The researchers show that the asteroid probably has a very loose internal structure and is only held together by very small cohesive forces and gravitational interactions. "On the basis of these conditions, we are able to use our numerical simulations to reproduce the outcome of the impact on Ryugu," explains Raducan.

The relationships between the characteristics of the projectiles and the size of the crater derived from the results indicate that the surfaces of small asteroids must be very young. "Our results also show that low cohesion can have a significant impact on crater formation. On Ryugu, there are various geological surface units that have different ages. This may be attributable to the influence of cohesion," adds Jutzi.

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Clouds less climate-sensitive than assumed

In a major field campaign in 2020, Dr. Raphaela Vogel who is now at Universität Hamburg's Center for Earth System Research and Sustainability (CEN) and an international team from the Laboratoire de Météorologie Dynamique in Paris and the Max Planck Institute for Meteorology in Hamburg analyzed observational data they and others collected in fields of cumulus clouds near the Atlantic island of Barbados. Their analysis revealed that these clouds' contribution to climate warming has to be reassessed.

"Trade-wind clouds influence the climate system around the globe, but the data demonstrate behavior differently than previously assumed. Consequently, an extreme rise in Earth's temperatures is less likely than previously thought," says Vogel, an atmospheric scientist. "Though this aspect is very important for more accurately projecting future climate scenarios, it definitely doesn't mean we can back off on climate protection."

To date, many climate models have simulated a major reduction in trade-wind clouds, which would mean much of their cooling function would be lost and the atmosphere would consequently warm even more. The new observational data shows that this isn't likely to occur.

What is certain is that, as global warming progresses, more water on the ocean's surface evaporates and the moisture near the base of trade-wind clouds increases. In contrast, the air masses in the upper part of the clouds are very dry and only become slightly moister. This produces a substantial difference in moisture above and below. In the atmosphere, this is dispelled when the air masses mix. The previous hypothesis: drier air is transported downward, causing the cloud droplets to evaporate more rapidly and making it more likely that the clouds will dissipate.

The observational data from Barbados now offers the first robust quantification as to how pronounced the vertical mixing actually is, and how this affects moisture and cloud cover as a whole. As such, it is the first data to shed light on a process that is essential to understanding climate change. In brief: more intensive mixing does not make the lower layers drier or make the clouds dissipate. Rather, the data shows that the cloud cover actually increases with increasing vertical mixing.

"That's good news, because it means that trade-wind clouds are far less sensitive to global warming than has long been assumed," says Vogel. "With our new observations and findings, we can now directly test how realistically climate models portray the occurrence of trade-wind clouds. In this regard, a new generation of high-resolution climate models that can simulate the dynamics of clouds around the globe down to scales of one kilometer are particularly promising. Thanks to them, future projections will be more accurate and reliable."

The month-long field campaign EUREC4A (2020) was designed by the team members around extended flights with two research aircraft, which were equipped with different instruments and operated at different altitudes, and shipboard measurements from the R/V Meteor -- A German research vessel managed by the University of Hamburg. One plane was used to drop hundreds of atmospheric probes from an altitude of nine kilometers. As they fell, the probes gathered atmospheric data on the temperature, moisture, pressure and wind. The other plane surveyed clouds at their base, at an altitude of 800 meters, while the ship performed surface-based measurements. The result: an unprecedented database that will help to understand the unclear role of clouds in the climate system -- and to more accurately predict their role in future climate change.

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Mammoth problem with extinction timeline

Precisely when mammoths went extinct has fascinated paleontologists for generations, perhaps because their decline coincided with the arrival of people to North and South America.

So it's only natural to wonder if humans contributed to the extinction of these enormous beasts of the ice age more than 10,000 years ago.

A University of Cincinnati paleontologist refutes the latest timeline published in 2021 in the journal Nature that suggested mammoths met their end much more recently than we believed. An international team of researchers examined environmental DNA of mammoth remains and more than 1,500 arctic plants to conclude that a wetter climate quickly changed the landscape from tundra grassland steppe to forested wetlands that could not support many of these big grazing animals, driving mammoths to extinction as recently as 3,900 years ago.

But in a rebuttal paper in Nature, UC College of Arts and Sciences assistant professor Joshua Miller and co-author Carl Simpson at the University of Colorado Boulder argue that the environmental DNA used to establish their updated timeline is more complex than previously recognized.

"The issue is you have no idea how old that DNA is," Miller said. "Sedimentary deposits are complex. Materials of different ages are routinely buried together."

Researchers have many tools to date sedimentary deposits and the materials contained in them. But not everything can be dated, Miller said.

"We can radiocarbon date all kinds of things: bones, teeth, charcoal, leaves. That's very powerful. But currently we can't independently date DNA found in sediments," Miller said.

From recent discoveries like the baby mammoth found in Canada this year, we know that many ice age animals that died tens of thousands of years ago can become mummified in the arctic's dry, cold environment. Miller said researchers can't tell whether environmental DNA preserved in sediment was shed from a living or dead animal.

"DNA is shed from organisms all the time," Miller said. "In fact, DNA continues to be shed long after the animal dies. In places where decomposition is slow, that means long-dead and even long-extinct species can continue to make their way into surrounding sediments. In the arctic and other cold-weather places, it can take thousands of years for something to decompose."

The researchers say the slow decomposition of animals in arctic regions could explain how mammoth DNA is showing up thousands of years later than the most recent mammoth fossil discovered. The paper notes that the mummified remains of elephant seals near Antarctica can be more than 5,000 years old.

Simpson said his work studying marine environments from recently eroded hillsides demonstrates how difficult it is to date ancient specimens.

"Seashells can sit on the seafloor for thousands of years. When you see shells on the beach, some could be from animals that died recently while others might be from shellfish that died millennia ago," Simpson said. "This happens in the vertebrate record as well."

Miller said the question remains what impact, if any, humans had on the global decline and extinction of mammoths. Humans were known to use fire to alter landscapes in profound ways, Miller said. They also hunted mammoths and made use of their ivory tusks.

So when did the last mammoths die off? Scientists say most mammoths went extinct more than 10,000 years ago, but remnant populations lived on islands such as Russia's Wrangel Island until much more recently.

This cohabitation with modern humans is one reason mammoths capture our imaginations, researchers said.

"They're tantalizingly similar to animals that live among us today," Miller said. "We can almost touch them. That makes mammoths really alluring. For many people they are the poster children of ice age megafauna."

Simpson noted that mammoths once lived on the Channel Islands of California near where he grew up. The islands were home to a pygmy mammoth weighing 2,000 pounds. Today, the biggest mammal on the island is a tiny endemic fox.

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Findings from 2,000-year-old Uluburun shipwreck reveal complex trade network

More than 2,000 years before the Titanic sunk in the North Atlantic Ocean, another famous ship wrecked in the Mediterranean Sea off the eastern shores of Uluburun -- in present-day Turkey -- carrying tons of rare metal. Since its discovery in 1982, scientists have been studying the contents of the Uluburun shipwreck to gain a better understanding of the people and political organizations that dominated the time period known as the Late

Now, a team of scientists, including Michael Frachetti, professor of archaeology in Arts & Sciences at Washington University in St. Louis, have uncovered a surprising finding: small communities of highland pastoralists living in present-day Uzbekistan in Central Asia produced and supplied roughly one-third of the tin found aboard the ship -- tin that was en route to markets around the Mediterranean to be made into coveted bronze metal.

The research, published on November 30 in Science Advances, was made possible by advances in geochemical analyses that enabled researchers to determine with high-level certainty that some of the tin originated from a prehistoric mine in Uzbekistan, more than 2,000 miles from Haifa, where the ill-fated ship loaded its cargo.

But how could that be? During this period, the mining regions of Central Asia were occupied by small communities of highlander pastoralists -- far from a major industrial center or empire. And the terrain between the two locations -- which passes through Iran and Mesopotamia -- was rugged, which would have made it extremely difficult to pass tons of heavy metal.

Frachetti and other archaeologists and historians were enlisted to help put the puzzle pieces together. Their findings unveiled a shockingly complex supply chain that involved multiple steps to get the tin from the small mining community to the Mediterranean marketplace.

"It appears these local miners had access to vast international networks and -- through overland trade and other forms of connectivity -- were able to pass this all-important commodity all the way to the Mediterranean," Frachetti said.

"It's quite amazing to learn that a culturally diverse, multiregional and multivector system of trade underpinned Eurasian tin exchange during the Late Bronze Age."

Adding to the mystique is the fact that the mining industry appears to have been run by small-scale local communities or free laborers who negotiated this marketplace outside of the control of kings, emperors or other political organizations, Frachetti said.

"To put it into perspective, this would be the trade equivalent of the entire United States sourcing its energy needs from small backyard oil rigs in central Kansas," he said.

About the research

The idea of using tin isotopes to determine where metal in archaeological artifacts originates dates to the mid-1990s, according to Wayne Powell, professor of earth and environmental sciences at Brooklyn College and a lead author on the study. However, the technologies and methods for analysis were not precise enough to provide clear answers. Only in the last few years have scientists begun using tin isotopes to directly correlate mining sites to assemblages of metal artifacts, he said.

"Over the past couple of decades, scientists have collected information about the isotopic composition of tin ore deposits around the world, their ranges and overlaps, and the natural mechanisms by which isotopic compositions were imparted to cassiterite when it formed," Powell said. "We remain in the early stages of such study. I expect that in future years, this ore deposit database will become quite robust, like that of Pb isotopes today, and the method will be used routinely."

Aslihan K. Yener, a research affiliate at the Institute for the Study of the Ancient World at New York University and a professor emerita of archaeology at the University of Chicago, was one of the early researchers who conducted lead isotope analyses. In the 1990s, Yener was part of a research team that conducted the first lead isotope analysis of the Uluburun tin. That analysis suggested that the Uluburun tin may have come from two sources -- the Kestel Mine in Turkey's Taurus Mountains and some unspecified location in central Asia.

"But this was shrugged off since the analysis was measuring trace lead and not targeting the origin of the tin," said Yener, who is a co-author of the present study.

Yener also was the first to discover tin in Turkey in the 1980s. At the time, she said the entire scholarly community was surprised that it existed there, right under their noses, where the earliest tin bronzes occurred.

Some 30 years later, researchers finally have a more definitive answer thanks to the advanced tin isotope analysis techniques: One-third of the tin aboard the Uluburun shipwreck was sourced from the Mušiston mine in Uzbekistan. The remaining two-thirds of the tin derived from the Kestel mine in ancient Anatolia, which is in present-day Turkey.

Findings offer glimpse into life 2,000-plus years ago

By 1500 B.C., bronze was the "high technology" of Eurasia, used for everything from weaponry to luxury items, tools and utensils. Bronze is primarily made from copper and tin. While copper is fairly common and can be found throughout Eurasia, tin is much rarer and only found in specific kinds of geological deposits, Frachetti said.

"Finding tin was a big problem for prehistoric states. And thus, the big question was how these major Bronze Age empires were fueling their vast demand for bronze given the lengths and pains to acquire tin as such a rare commodity. Researchers have tried to explain this for decades," Frachetti said.

The Uluburun ship yielded the world's largest Bronze Age collection of raw metals ever found -- enough copper and tin to produce 11 metric tons of bronze of the highest quality. Had it not been lost to sea, that metal would have been enough to outfit a force of almost 5,000 Bronze Age soldiers with swords, "not to mention a lot of wine jugs," Frachetti said.

"The current findings illustrate a sophisticated international trade operation that included regional operatives and socially diverse participants who produced and traded essential hard-earth commodities throughout the late Bronze Age political economy from Central Asia to the Mediterranean," Frachetti said.

Unlike the mines in Uzbekistan, which were set within a network of small-scale villages and mobile pastoralists, the mines in ancient Anatolia during the Late Bronze Age were under the control of the Hittites, an imperial global power of great threat to Ramses the Great of Egypt, Yener explained.

The findings also show that life 2,000-plus years ago was not that different from what it is today.

"With the disruptions due to COVID-19 and the war in Ukraine, we have become aware of how we are reliant on complex supply chains to maintain our economy, military and standard of living," Powell said. "This is true in prehistory as well. Kingdoms rose and fell, climatic conditions shifted and new peoples migrated across Eurasia, potentially disrupting or redistributing access to tin, which was essential for both weapons and agricultural tools.

"Using tin isotopes, we can look across each of these archaeologically evident disruptions in society and see connections were severed, maintained or redefined. We already have DNA analysis to show relational connections. Pottery, funerary practices, etc., illustrate the transmission and connectivity of ideas. Now with tin isotopes, we can document the connectivity of long-distance trade networks and their sustainability."

More clues to explore

The current research findings settle decades-old debates about the origins of the metal on the Uluburun shipwreck and Eurasian tin exchange during the Late Bronze Age. But there are still more clues to explore.

After they were mined, the metals were processed for shipping and ultimately melted into standardized shapes -- known as ingots -- for transporting. The distinct shapes of the ingots served as calling cards for traders to know from where they originated, Frachetti said.

Many of the ingots aboard the Uluburun ship were in the "oxhide" shape, which was previously believed to have originated in Cyprus. However, the current findings suggest the oxhide shape could have originated farther east. Frachetti said he and other researchers plan to continue studying the unique shapes of the ingots and how they were used in trade.

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Mysteriously bright flash is a black hole jet pointing straight toward Earth, astronomers say

Astronomers have determined the source of an incredibly bright X-ray, optical and radio signal appearing from halfway across the Universe.

The signal, named AT 2022cmc, was discovered earlier this year by the Zwicky Transient Facility in California. Findings published today in Nature Astronomy, suggest that it is likely from a jet of matter, streaking out from a supermassive black hole at close to the speed of light.

The team, including researchers from MIT and the University of Birmingham, believe the jet is the product of a black hole that suddenly began devouring a nearby star, releasing a huge amount of energy in the process. Their findings could shed new light on how supermassive black holes feed and grow.

Astronomers have observed other such "tidal disruption events," or TDEs, in which a passing star is torn apart by a black hole's tidal forces. However AT 2022cmc is brighter than any TDE discovered to date, and is also the farthest TDE ever detected, at some 8.5 billion light years away.

The team measured the distance to the AT 2022cmc using the European Southern Observatory's Very Large Telescope, in Chile.

Dr Matt Nicholl, associate professor at the University of Birmingham, said: "Our spectrum told us that the source was hot: around 30,000 degrees, which is typical for a TDE. But we also saw some absorption of light by the galaxy where this event occurred. These absorption lines were highly shifted towards redder wavelengths, telling us that this galaxy was much further away than we expected!"

How could such a distant event appear so bright in our sky? The team says the black hole's jet may be pointing directly toward Earth, making the signal appear brighter than if the jet were pointing in any other direction. The effect is "Doppler boosting," and is similar to the amped-up sound of a passing siren.

AT 2022cmc is the fourth Doppler-boosted TDE ever detected and the first such event that has been observed since 2011. It is also the first boosted TDE discovered using an optical sky survey. As more powerful telescopes start up in the coming years, they will reveal more TDEs, which can shed light on how supermassive black holes grow and shape the galaxies around them.

Following AT 2022cmc's initial discovery, the team focused in on the signal using the Neutron star Interior Composition ExploreR (NICER), an X-ray telescope that operates aboard the International Space Station.

"Things looked pretty normal the first three days," recalls Dheeraj "DJ" Pasham, who was first author on the study. "Then we looked at it with an X-ray telescope, and what we found was, the source was 100 times more powerful than the most powerful gamma-ray burst afterglow."

Typically, such bright flashes in the sky are gamma-ray bursts -- extreme jets of X-ray emissions that spew from the collapse of massive stars.

Dr Benjamin Gompertz, assistant professor at the University of Birmingham, led the gamma-ray burst comparison analysis. "Gamma-ray bursts are the usual suspects for events like this." he said. "However, as bright as they are, there is only so much light a collapsing star can produce. Because AT 2022cmc was so bright and lasted so long, we knew that something truly gargantuan must be powering it -- a supermassive black hole."

The extreme X-ray activity is believed to be powered by an "extreme accretion episode" when the shredded star creates a whirlpool of debris as it falls into the black hole. Indeed, the team found that AT 2022cmc's X-ray luminosity was comparable to, though brighter than, three previously detected TDEs.

"It's probably swallowing the star at the rate of half the mass of the sun per year," Pasham estimates. "A lot of this tidal disruption happens early on, and we were able to catch this event right at the beginning, within one week of the black hole starting to feed on the star."

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Fossil overturns more than a century of knowledge about the origin of modern birds

Fossilised fragments of a skeleton, hidden within a rock the size of a grapefruit, have helped upend one of the longest-standing assumptions about the origins of modern birds.

Researchers from the University of Cambridge and the Natuurhistorisch Museum Maastricht found that one of the key skull features that characterises 99% of modern birds -- a mobile beak -- evolved before the mass extinction event that killed all large dinosaurs, 66 million years ago.

This finding also suggests that the skulls of ostriches, emus and their relatives evolved 'backwards', reverting to a more primitive condition after modern birds arose.

Using CT scanning techniques, the Cambridge team identified bones from the palate, or the roof of the mouth, of a new species of large ancient bird, which they named Janavis finalidens. It lived at the very end of the Age of Dinosaurs and was one of the last toothed birds to ever live. The arrangement of its palate bones shows that this 'dino-bird' had a mobile, dexterous beak, almost indistinguishable from that of most modern birds.

For more than a century, it had been assumed that the mechanism enabling a mobile beak evolved after the extinction of the dinosaurs. However, the new discovery, reported in the journal Nature, suggests that our understanding of how the modern bird skull came to be needs to be re-evaluated.

Each of the roughly 11,000 species of birds on Earth today is classified into one of two over-arching groups, based on the arrangement of their palate bones. Ostriches, emus and their relatives are classified into the palaeognath, or 'ancient jaw' group, meaning that, like humans, their palate bones are fused together into a solid mass.

All other groups of birds are classified into the neognath, or 'modern jaw' group, meaning that their palate bones are connected by a mobile joint. This makes their beaks much more dexterous, helpful for nest-building, grooming, food-gathering, and defence.

The two groups were originally classified by Thomas Huxley, the British biologist known as 'Darwin's Bulldog' for his vocal support of Charles Darwin's theory of evolution. In 1867, he divided all living birds into either the 'ancient' or 'modern' jaw groups. Huxley's assumption was that the 'ancient' jaw configuration was the original condition for modern birds, with the 'modern' jaw arising later.

"This assumption has been taken as a given ever since," said Dr Daniel Field from Cambridge's Department of Earth Sciences, the paper's senior author. "The main reason this assumption has lasted is that we haven't had any well-preserved fossil bird palates from the period when modern birds originated."

The fossil, Janavis, was found in a limestone quarry near the Belgian-Dutch border in the 1990s and was first studied in 2002. It dates from 66.7 million years ago, during the last days of the dinosaurs. Since the fossil is encased in rock, scientists at the time could only base their descriptions on what they could see from the outside. They described the bits of bone sticking out from the rock as fragments of skull and shoulder bones, and put the unremarkable-looking fossil back in storage.

Nearly 20 years later, the fossil was loaned to Field's group in Cambridge, and Dr Juan Benito, then a PhD student, started giving it another look.

"Since this fossil was first described, we've started using CT scanning on fossils, which enables us to see through the rock and view the entire fossil," said Benito, now a postdoctoral researcher at Cambridge, and the paper's lead author. "We had high hopes for this fossil -- it was originally said to have skull material, which isn't often preserved, but we couldn't see anything that looked like it came from a skull in our CT scans, so we gave up and put the fossil aside."

During the early days of Covid-19 lockdown, Benito took the fossil out again. "The earlier descriptions of the fossil just didn't make sense -- there was a bone I was really puzzled by. I couldn't see how what was first described as a shoulder bone could actually be a shoulder bone," he said.

"It was my first in-person interaction in months: Juan and I had a socially distanced outdoor meeting, and he passed the mystery fossil bone to me," said Field, who is also the Curator of Ornithology at Cambridge's Museum of Zoology. "I could see it wasn't a shoulder bone, but there was something familiar about it."

"Then we realised we'd seen a similar bone before, in a turkey skull," said Benito. "And because of the research we do at Cambridge, we happen to have things like turkey skulls in our lab, so we brought one out and the two bones were almost identical."

The realisation that the bone was a skull bone, and not a shoulder bone, led the researchers to conclude that the unfused 'modern jaw' condition, which turkeys share, evolved before the 'ancient jaw' condition of ostriches and their relatives. For an unknown reason, the fused palates of ostriches and kin must have evolved at some point after modern birds were already established.

Two of the key characteristics we use to differentiate modern birds from their dinosaur ancestors are a toothless beak and a mobile upper jaw. While Janavis finalidens still had teeth, making it a pre-modern bird, its jaw structure is that of the modern, mobile kind.

"Using geometric analyses, we were able to show that the shape of the fossil palate bone was extremely similar to those of living chickens and ducks" said Pei-Chen Kuo, a co-author of the study. Added co-author Klara Widrig: "Surprisingly, the bird palate bones that are the least similar to that of Janavis are from ostriches and their kin." Both Kuo and Widrig are PhD students in Field's lab at Cambridge.

"Evolution doesn't happen in a straight line," said Field. "This fossil shows that the mobile beak -- a condition we had always thought post-dated the origin of modern birds, actually evolved before modern birds existed. We've been completely backwards in our assumptions of how the modern bird skull evolved for well over a century."

The researchers say that while this discovery does not mean that the entire bird family tree needs to be redrawn, it does rewrite our understanding of a key evolutionary feature of modern birds.

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Silent synapses are abundant in the adult brain

MIT neuroscientists have discovered that the adult brain contains millions of "silent synapses" -- immature connections between neurons that remain inactive until they're recruited to help form new memories.

Until now, it was believed that silent synapses were present only during early development, when they help the brain learn the new information that it's exposed to early in life. However, the new MIT study revealed that in adult mice, about 30 percent of all synapses in the brain's cortex are silent.

The existence of these silent synapses may help to explain how the adult brain is able to continually form new memories and learn new things without having to modify existing conventional synapses, the researchers say.

"These silent synapses are looking for new connections, and when important new information is presented, connections between the relevant neurons are strengthened. This lets the brain create new memories without overwriting the important memories stored in mature synapses, which are harder to change," says Dimitra Vardalaki, an MIT graduate student and the lead author of the new study.

Mark Harnett, an associate professor of brain and cognitive sciences, is the senior author of the paper, which appears today in Nature. Kwanghun Chung, an associate professor of chemical engineering at MIT, is also an author.

A surprising discovery

When scientists first discovered silent synapses decades ago, they were seen primarily in the brains of young mice and other animals. During early development, these synapses are believed to help the brain acquire the massive amounts of information that babies need to learn about their environment and how to interact with it. In mice, these synapses were believed to disappear by about 12 days of age (equivalent to the first months of human life).

However, some neuroscientists have proposed that silent synapses may persist into adulthood and help with the formation of new memories. Evidence for this has been seen in animal models of addiction, which is thought to be largely a disorder of aberrant learning.

Theoretical work in the field from Stefano Fusi and Larry Abbott of Columbia University has also proposed that neurons must display a wide range of different plasticity mechanisms to explain how brains can both efficiently learn new things and retain them in long-term memory. In this scenario, some synapses must be established or modified easily, to form the new memories, while others must remain much more stable, to preserve long-term memories.

In the new study, the MIT team did not set out specifically to look for silent synapses. Instead, they were following up on an intriguing finding from a previous study in Harnett's lab. In that paper, the researchers showed that within a single neuron, dendrites -- antenna-like extensions that protrude from neurons -- can process synaptic input in different ways, depending on their location.

As part of that study, the researchers tried to measure neurotransmitter receptors in different dendritic branches, to see if that would help to account for the differences in their behavior. To do that, they used a technique called eMAP (epitope-preserving Magnified Analysis of the Proteome), developed by Chung. Using this technique, researchers can physically expand a tissue sample and then label specific proteins in the sample, making it possible to obtain super-high-resolution images.

While they were doing that imaging, they made a surprising discovery. "The first thing we saw, which was super bizarre and we didn't expect, was that there were filopodia everywhere," Harnett says.

Filopodia, thin membrane protrusions that extend from dendrites, have been seen before, but neuroscientists didn't know exactly what they do. That's partly because filopodia are so tiny that they are difficult to see using traditional imaging techniques.

After making this observation, the MIT team set out to try to find filopodia in other parts of the adult brain, using the eMAP technique. To their surprise, they found filopodia in the mouse visual cortex and other parts of the brain, at a level 10 times higher than previously seen. They also found that filopodia had neurotransmitter receptors called NMDA receptors, but no AMPA receptors.

A typical active synapse has both of these types of receptors, which bind the neurotransmitter glutamate. NMDA receptors normally require cooperation with AMPA receptors to pass signals because NMDA receptors are blocked by magnesium ions at the normal resting potential of neurons. Thus, when AMPA receptors are not present, synapses that have only NMDA receptors cannot pass along an electric current and are referred to as "silent."

Unsilencing synapses

To investigate whether these filopodia might be silent synapses, the researchers used a modified version of an experimental technique known as patch clamping. This allowed them to monitor the electrical activity generated at individual filopodia as they tried to stimulate them by mimicking the release of the neurotransmitter glutamate from a neighboring neuron.

Using this technique, the researchers found that glutamate would not generate any electrical signal in the filopodium receiving the input, unless the NMDA receptors were experimentally unblocked. This offers strong support for the theory the filopodia represent silent synapses within the brain, the researchers say.

The researchers also showed that they could "unsilence" these synapses by combining glutamate release with an electrical current coming from the body of the neuron. This combined stimulation leads to accumulation of AMPA receptors in the silent synapse, allowing it to form a strong connection with the nearby axon that is releasing glutamate.

The researchers found that converting silent synapses into active synapses was much easier than altering mature synapses.

"If you start with an already functional synapse, that plasticity protocol doesn't work," Harnett says. "The synapses in the adult brain have a much higher threshold, presumably because you want those memories to be pretty resilient. You don't want them constantly being overwritten. Filopodia, on the other hand, can be captured to form new memories."

"Flexible and robust"

The findings offer support for the theory proposed by Abbott and Fusi that the adult brain includes highly plastic synapses that can be recruited to form new memories, the researchers say.

"This paper is, as far as I know, the first real evidence that this is how it actually works in a mammalian brain," Harnett says. "Filopodia allow a memory system to be both flexible and robust. You need flexibility to acquire new information, but you also need stability to retain the important information."

The researchers are now looking for evidence of these silent synapses in human brain tissue. They also hope to study whether the number or function of these synapses is affected by factors such as aging or neurodegenerative disease.

"It's entirely possible that by changing the amount of flexibility you've got in a memory system, it could become much harder to change your behaviors and habits or incorporate new information," Harnett says. "You could also imagine finding some of the molecular players that are involved in filopodia and trying to manipulate some of those things to try to restore flexible memory as we age."

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Team recycles previously unrecyclable plastic

PVC, or polyvinyl chloride, is one of the most produced plastics in the United States and the third highest by volume in the world.

PVC makes up a vast amount of plastics we use on a daily basis. Much of the plastic used in hospital equipment -- tubing, blood bags, masks and more -- is PVC, as is most of the piping used in modern plumbing. Window frames, housing trim, siding and flooring are made of, or include, PVC. It coats electrical wiring and comprises materials such as shower curtains, tents, tarps and clothing.

It also has a zero percent recycling rate in the United States.

Now, University of Michigan researchers, led by study first author Danielle Fagnani and principal investigator Anne McNeil, have discovered a way to chemically recycle PVC into usable material. The most fortuitous part of the study? The researchers found a way to use the phthalates in the plasticizers -- one of PVC's most noxious components -- as the mediator for the chemical reaction. Their results are published in the journal Nature Chemistry.

"PVC is the kind of plastic that no one wants to deal with because it has its own unique set of problems," said Fagnani, who completed the work as a postdoctoral researcher in the U-M Department of Chemistry. "PVC usually contains a lot of plasticizers, which contaminate everything in the recycling stream and are usually very toxic. It also releases hydrochloric acid really rapidly with some heat."

Plastic is typically recycled by melting it down and reforming it into the lower quality materials in a process called mechanical recycling. But when heat is applied to PVC, one of its primary components, called plasticizers, leach out of the material very easily, McNeil says.

They then can slip into other plastics in the recycling stream. Additionally, hydrochloric acid releases easily out of PVC with heat. It could corrode the recycling equipment and cause chemical burns to skin and eyes -- not ideal for workers in a recycling plant.

What's more, phthalates -- a common plasticizer -- are highly toxic endocrine disruptors, which means they can interfere with the thyroid hormone, growth hormones and hormones involved with reproduction in mammals, including humans.

So, to find a way to recycle PVC that does not require heat, Fagnani began exploring electrochemistry. Along the way, she and the team discovered that the plasticizer that presents one of the major recycling difficulties could be used in the method to break down PVC. In fact, the plasticizer improves the efficiency of the method, and the electrochemical method resolves the issue with hydrochloric acid.

"What we found is that it still releases hydrochloric acid, but at a much slower, more controlled rate," Fagnani said.

PVC is a polymer with a hydrocarbon backbone, Fagnani says, composed of single carbon-carbon bonds. Attached to every other carbon group is a chlorine group. Under heat activation, hydrochloric acid rapidly pops off, resulting in a carbon-carbon double bond along the polymer's backbone.

But the research team instead uses electrochemistry to introduce an electron into the system, which causes the system to have a negative charge. This breaks the carbon-chloride bond and results in a negatively charged chloride ion. Because the researchers are using electrochemistry, they can meter the rate at which electrons are introduced into the system -- which controls how quickly hydrochloric acid is produced.

The acid can then be used by industries as a reagent for other chemical reactions. The chloride ions can also be used to chlorinate small molecules called arenes. These arenes can be used in pharmaceutical and agricultural components. There is material left from the polymer, for which McNeil says the group is still looking for a use. Fagnani says the study shows how scientists might think about chemically recycling other difficult materials.

"Let's be strategic with the additives that are in plastics formulations. Let's think about the during-use and end-of-use from the perspective of the additives," said Fagnani, who is now a research scientist at Ashland, a company focused on making biodegradable specialty additives to consumer goods such as laundry detergents, sunscreens and shampoos. "Current group members are trying to improve the efficiency of this process even more."

The focus of McNeil's lab has been to develop ways to chemically recycle different kinds of plastics. Breaking plastics into their constituent parts could produce non-degraded materials that industry can incorporate back into production.

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Non-detection of key signal allows astronomers to determine what the first galaxies were -- and weren't -- like

Researchers have been able to make some key determinations about the first galaxies to exist, in one of the first astrophysical studies of the period in the early Universe when the first stars and galaxies formed, known as the cosmic dawn.

Using data from India's SARAS3 radio telescope, researchers led by the University of Cambridge were able to look at the very early Universe -- just 200 million years after the Big Bang -- and place limits on the mass and energy output of the first stars and galaxies.

Counterintuitively, the researchers were able to place these limits on the earliest galaxies by not finding the signal they had been looking for, known as the 21-centimetre hydrogen line.

This non-detection allowed the researchers to make other determinations about the cosmic dawn, placing restraints on the first galaxies, enabling them to rule out scenarios including galaxies which were inefficient heaters of cosmic gas and efficient producers of radio emissions.

While we cannot yet directly observe these early galaxies, the results, reported in the journal Nature Astronomy, represent an important step in understanding how our Universe transitioned from mostly empty to one full of stars.

Understanding the early Universe, when the first stars and galaxies formed, is one of the major goals of new observatories. The results obtained using the SARAS3 data are a proof-of-concept study that paves the way to understanding this period in the development of the Universe.

The SKA project -- involving two next-generation telescopes due to be completed by the end of the decade -- will likely be able to make images of the early Universe, but for current telescopes the challenge is to detect the cosmological signal of the first stars re-radiated by thick hydrogen clouds.

This signal is known as the 21-centimetre line -- a radio signal produced by hydrogen atoms in the early Universe. Unlike the recently launched JWST, which will be able to directly image individual galaxies in the early Universe, studies of the 21-centimetre line, made with radio telescopes such as the Cambridge-led REACH (Radio Experiment for the Analysis of Cosmic Hydrogen), can tell us about entire populations of even earlier galaxies. The first results are expected from REACH early in 2023.

To detect the 21-centimetre line, astronomers look for a radio signal produced by hydrogen atoms in the early Universe, affected by light from the first stars and the radiation behind the hydrogen fog. Earlier this year, the same researchers developed a method which they say will allow them to see through the fog of the early universe and detect light from the first stars. Some of these techniques have been already put to practice in the current study.

In 2018, another research group operating the EDGES experiment published a result that hinted at a possible detection of this earliest light. The reported signal was unusually strong compared to what is expected in the simplest astrophysical picture of the early Universe. Recently, the SARAS3 data disputed this detection: the EDGES result is still awaiting confirmation from independent observations.

In a re-analysis of the SARAS3 data, the Cambridge-led team tested a variety of astrophysical scenarios which could potentially explain the EDGES result, but they did not find a corresponding signal. Instead, the team was able to place some limits on properties of the first stars and galaxies.

The results of the SARAS3 analysis are the first time that radio observations of the averaged 21-centimetre line have been able to provide an insight to the properties of the first galaxies in the form of limits of their main physical properties.

Working with collaborators in India, Australia and Israel, the Cambridge team used data from the SARAS3 experiment to look for signals from cosmic dawn, when the first galaxies formed. Using statistical modelling techniques, the researchers were not able to find a signal in the SARAS3 data.

"We were looking for a signal with a certain amplitude," said Harry Bevins, a PhD student from Cambridge's Cavendish Laboratory and the paper's lead author. "But by not finding that signal, we can put a limit on its depth. That, in turn, begins to inform us about how bright the first galaxies were."

"Our analysis showed that the hydrogen signal can inform us about the population of first stars and galaxies," said co-lead author Dr Anastasia Fialkov from Cambridge's Institute of Astronomy. "Our analysis places limits on some of the key properties of the first sources of light including the masses of the earliest galaxies and the efficiency with which these galaxies can form stars. We also address the question of how efficiently these sources emit X-ray, radio and ultraviolet radiation."

"This is an early step for us in what we hope will be a decade of discoveries about how the Universe transitioned from darkness and emptiness to the complex realm of stars, galaxies and other celestial objects we can see from Earth today," said Dr Eloy de Lera Acedo from Cambridge's Cavendish Laboratory, who co-led the research.

The observational study, the first of its kind in many respects, excludes scenarios in which the earliest galaxies were both more than a thousand times as bright as present galaxies in their radio-band emission and were poor heaters of hydrogen gas.

"Our data also reveals something which has been hinted at before, which is that the first stars and galaxies could have had a measurable contribution to the background radiation that appeared as a result of the Big Bang and which has been travelling towards us ever since," said de Lera Acedo, "We are also establishing a limit to that contribution."

"It's amazing to be able to look so far back in time -- to just 200 million years after the Big Bang- and be able to learn about the early Universe," said Bevins.

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Animals are key to restoring the world's forests

As UN climate talks close in Egypt and biodiversity talks begin in Montreal, attention is on forest restoration as a solution to the twin evils roiling our planet. Forests soak up atmospheric carbon dioxide and simultaneously create habitat for organisms. So far, efforts to help forests bounce back from deforestation have typically focused on increasing one thing -- trees -- over anything else. But a new report uncovers a powerful, yet largely overlooked, driver of forest recovery: animals. The study by an international team from the Max Planck Institute of Animal Behavior, Yale School of the Environment, the New York Botanical Garden, and the Smithsonian Tropical Research Institute examined a series of regenerating forests in central Panama spanning 20 to 100 years post-abandonment. The unique long-term data set revealed that animals, by carrying a wide variety of seeds into deforested areas, are key to the recovery of tree species richness and abundance to old-growth levels after only 40-70 years of regrowth. The article, published in Philosophical Transactions of the Royal Society B, is part of a theme issue focused on forest landscape restoration as part of the UN Decade on Ecosystem Restoration.

"Animals are our greatest allies in reforestation," says Daisy Dent, a tropical ecologist from MPI-AB and the study's senior author. "Our study prompts a rethink of reforestation efforts to be about more than just establishing plant communities."

The report also notes that situating regenerating forests near patches of old growth, and reducing hunting, encourages animals to colonize and establish. "We show that considering the wider ecosystem, as well as features of the landscape, improves restoration efforts," says Sergio Estrada-Villegas, a biologist now at Universidad del Rosario (Bogotá, Colombia) and the study's first author.

Seed dispersal by animals is key to forest expansion. In the tropics, over 80% of tree species can be dispersed by animals, which transport seeds throughout the landscape. Despite this, forest restoration efforts continue to focus on increasing tree cover rather than reestablishing the animal-plant interactions that underpin ecosystem function. "Figuring out how animals contribute to reforestation is prohibitively hard because you need detailed information about which animals eat which plants," says Estrada-Villegas.

The forest at the Barro Colorado Nature Monument (BCNM), in the Panama Canal, offers a unique solution to this problem. In one of the best studied tropical forests in the world, generations of scientists at have documented frugivore interactions to understand which groups of animals disperse which tree species.

In the present study, the team led by Estrada-Villegas and Dent examined this unique long-term dataset to determine the proportion of plants dispersed by four groups of animals -- flightless mammals, large birds, small birds, and bats -- and how this proportion changed over a century of natural restoration.

Their results offer the most detailed data of animal seed dispersal recovery across the longest timeframe of natural restoration. "Most studies examine the first 30 years of succession, but our data spanning 100 years gives us a rare glimpse into what happens in the late phase of restoration," says Dent.

The study found that young regenerating forests were made up mostly of trees dispersed by small birds. But as the forest aged, trees dispersed by larger birds increased. Surprisingly, however, the majority of plants were dispersed by terrestrial mammals across all forest ages -- from 20 years old to old growth. "This result is quite unusual for post-agricultural regenerating forests," says Dent. "It is likely that the presence of large tracts of preserved forests near our secondary stands, coupled with low hunting, has allowed the mammal populations to thrive and to bring an influx of seeds from neighboring patches."

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Earth's many new lakes

The number of lakes on our planet has increased substantially in recent decades, according to a unique global survey of 3.4 million lakes that the University of Copenhagen has taken part in. There has been a particular increase in the number of small lakes, which unfortunately, emit large amounts of greenhouse gas. The development is of great importance for Earth's carbon account, global ecosystems, and human access to water resources.

Bacteria and fungi feeding on dead plants and animals at the bottom of a lake emit vast amounts of CO2, methane, nitrous oxide, and other gases. Some of these gases end up in the atmosphere. This mechanism causes lakes to act like greenhouse gas factories. In fact, freshwater lakes probably account for 20% of all global CO2 fossil fuel emissions into Earth's atmosphere. Forecasts suggest that climate change will cause lakes to emit an ever-greater share of greenhouse gases in the future.

This is just one of the reasons why it is important to know how many and how big these lakes are, as well as how they develop. Until now, this information was unknown. Scientific researchers from the University of Copenhagen and other universities have now prepared a more accurate and detailed map of the world's lakes than has ever existed. The researchers mapped 3.4 million lakes and their evolution over the past four decades using high-resolution satellite imagery combined with artificial intelligence.

The survey shows that between 1984 and 2019, the area of global lake surfaces grew by over 46,000 km2 -- slightly more than the surface area of Denmark.

"There have been major and rapid changes with lakes in recent decades that affect greenhouse gas accounts, as well as ecosystems and access to water resources. Among other things, our newfound knowledge of the extent and dynamics of lakes allows us to better calculate their potential carbon emissions," explains Jing Tang, an Assistant Professor at the Department of Biology and co-author of the study, which is now published in Nature Communications.

According to the study's calculations, the annual increase of CO2 emissions from lakes during the period is 4.8 teragrams (10^12, trillion) of carbon -- which equals to the CO2 emission increase of the United Kingdom in 2012.

Small lakes, large CO2 emissions

More and more small lakes (<1 km2) have appeared since 1984. The number of these small lakes is especially important according to the researchers, because they emit the most greenhouse gas in relation to their size. While small lakes account for just 15% of total lake area, they account for 25% of CO2 and 37% of methane emissions. Furthermore, they also contribute to 45% and 59% of the net increases of the lake CO2 and CH4 emissionsover the period 1984-2019.

"Small lakes emit a disproportionate amount of greenhouse gases because they typically accumulate more organic matter, which is converted into gases. And also, because they are often shallow. This makes it easier for gases to reach the surface and up into the atmosphere," explains Jing Tang, who continues:

"At the same time, small lakes are much more sensitive to changes in climate and weather, as well as to human disturbances. As a result, their sizes and water chemistry fluctuate greatly. Thus, while it is important to identify and map them, it is also more demanding. Fortunately, we've been able to do justify that."

The mapping also reveals that there are two main reasons for Earth's many new lakes: climate change and human activities. Reservoirs account for more than half of increased lake area -- i.e., artificial lakes. The other half are primarily created by melting glaciers or thawing permafrost.

New figures sent to the UN

According to the researchers, the new dataset offers a range of regional and global applications.

"I have sent our new greenhouse gas emission estimates to the people responsible for calculating the global carbon budget, those who are behind the UN's IPCC climate reports. I hope they include them in updating the global emission numbers," says Jing Tang.

She adds:

"Furthermore, the dataset can be used to make better estimates of water resources in freshwater lakes and to better assess the risk of flooding, as well as for better lake management -- because lake area impacts biodiversity too."

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DNA sequence enhances understanding origins of jaws

Researchers at Uppsala University have discovered and characterised a DNA sequence found in jawed vertebrates, such as sharks and humans, but absent in jawless vertebrates, such as lampreys. This DNA is important for the shaping of the joint surfaces during embryo development.

The vast majority of vertebrate species living today, including humans, belong to the jawed vertebrate group. The development of articulating jaws during vertebrate evolution was one of the most significant evolutionary transitions from jawless to jawed vertebrates, taking place at least 423 million years ago. The lower and upper jaws were initially connected by the primary jaw joint. However, during the evolution of mammals this moved to the middle ear to enhance hearing and was replaced by the secondary jaw joint, which is how humans are constructed today.

The primary jaw joint is formed during embryonic development and has an active gene which contains sequence information for a specific protein -- transcription factor Nkx3.2. This protein has long been thought to have played a major role in the evolution of this jaw joint, but little was known before about how its gene activity is regulated in the jaw joint cells.

Typically, genes are activated with help from DNA sequences, known as enhancers, that do not contain gene sequence information. Furthermore, such 'regulatory' DNA can contribute to the activation of the gene only in a certain cell type and can be conserved among different animal species.

"We searched through the genome sequences of many different vertebrate species and only found the DNA sequence near the Nkx3.2 gene in jawed vertebrates -- not in jawless ones. When we injected these DNA sequences from jawed vertebrates into zebrafish embryos, they were all activated in the jaw joint cells. The fact that their ability to activate has been preserved for over 400 million years shows how important it is for jawed vertebrates," notes Tatjana Haitina, researcher at Uppsala University, who led the study.

"In experiments where we deleted the newly discovered DNA sequence from the zebrafish genome using the CRISPR/Cas9 technique, we saw that the early activation of the Nkx3.2 gene was reduced, which caused defects in the jaw joint shape. It turned out that these defects were later repaired, suggesting that there is additional regulatory DNA somewhere in the genome that controls the activation of the Nkx3.2 gene and is waiting to be discovered," adds Jake Leyhr, doctoral student student in the research team.

The researchers hope that their discovery is an important step towards eventually understanding the process behind the origins of vertebrate jaws.

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Elusive, dusty inner region of distant galaxy

An international team of scientists has achieved the milestone of directly observing the long-sought, innermost dusty ring around a supermassive black hole, at a right angle to its emerging jet. Such a structure was thought to exist in the nucleus of galaxies but had been difficult to observe directly because intervening material obscured our line of sight.

Now the inner disk is detected using the highest spatial resolution in the infrared wavelengths ever done for an extragalactic object. The new discovery was just published in The Astrophysical Journal.

"This is a very exciting step forward to view the inner region of a distant galaxy with such fine detail," said Gail Schaefer, Associate Director of the Center for High Angular Resolution Astronomy (CHARA) Array.

A supermassive black hole is thought to exist at the center of every large galaxy. As material in the surrounding region gets pulled toward the center, the gas forms a hot and bright disk-like structure. In some cases, a jet emerges from the vicinity of the black hole in a direction at a right angle to the disk. However, this flat structure, which is essentially the 'engine' of this active supermassive black hole system, has never been directly seen because it's too small to be captured by conventional telescopes.

One way to approach this key structure is to directly see an outer 'dusty ring' -- interstellar gas contains dust grains, tiny solid particles made of heavy elements, which can only survive in the outer region where temperature is low enough (< ~1500K -- otherwise metals evaporate). The heated dust emits thermal infrared radiation, and thus would look like an outer ring around the black hole, if the central system indeed has a flat structure. The detection of its structure would be a key step to delineate how the central engine works.

Attempts to see this structure from edge-on directions are difficult, because the system is obscured by the same dust acting as an absorber of light. Instead, in the new investigation the team focused on a system with a face-on view, the brightest such object in the nearby universe. However, the detection needed very high spatial resolution in the infrared wavelengths, and at the same time, a large array of telescopes that is laid out suitably to observe objects at different orientations.

The Georgia State University CHARA Array interferometer at the Mount Wilson Observatory in California is the only facility which meets both of these requirements. The Array consists of 6 telescopes, each of which has a 1-meter diameter mirror, that are combined to achieve the spatial resolution of a much larger telescope. While each individual telescope is relatively small, the array layout is optimized to observe objects in a variety of angles and with large distances between telescopes. This achieves a very high spatial resolution capability. The CHARA Array actually has the sharpest eyes in the world in infrared wavelengths.

With the CHARA Array, the team finally detected the dusty ring, at a right angle to the emerging jet in the center of the galaxy called NGC 4151.

"We've been hoping to see this structure in a bare nucleus object for a long, long time," says Makoto Kishimoto, principal investigator of the project at Kyoto Sangyo University.

A big boost was that each telescope has recently added a new system called "adaptive optics."

Matt Anderson, a postdoctoral researcher at the CHARA Array who played a critical role in conducting the observations, says "This greatly increased the injection rate of the light, compensating for the relatively small collecting mirror to observe the extragalactic target, which is much fainter than the stellar targets typically observed in our Galaxy."

Over the last nearly 40 years, researchers in the field believed that this dusty ring is a key to understanding different characteristics of accreting supermassive blackhole systems. The properties we observe depend on whether we have an obscured, edge-on view or clear, face-on view of the nucleus of the active galaxy. The detection of this ring-like structure validates this model.

Furthermore, the detection probably is not just an indication of a flat structure. Additional studies have been showing that the structure seen at slightly longer infrared wavelengths, corresponding to an even larger outer region, seems elongated along the jet, and not at a right angle to it. This has been interpreted as an indication for a dusty wind being blown out toward the jet direction. The present finding that the inner structure looks flat and perpendicular to the jet, is an important link to the windy structure and its interaction with the rest of the galaxy surrounding the active black hole system.

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Ancient Roman coins reveal long-lost emperor

A gold coin long dismissed as a forgery appears to be authentic and depicts a long-lost Roman emperor named Sponsian, according to a new UCL-led study.

The coin, housed at The Hunterian collection at the University of Glasgow, was among a handful of coins of the same design unearthed in Transylvania, in present-day Romania, in 1713. They have been regarded as fakes since the mid-19th-century, due to their crude, strange design features and jumbled inscriptions.

In the new study, published in PLOS ONE, researchers compared the Sponsion coin with other Roman coins kept at The Hunterian, including two that are known to be genuine.

They found minerals on the coin's surface that were consistent with it being buried in soil over a long period of time, and then exposed to air. These minerals were cemented in place by silica -- cementing that would naturally occur over a long time in soil. The team also found a pattern of wear and tear that suggested the coin had been in active circulation.

Lead author Professor Paul N. Pearson (UCL Earth Sciences) said: "Scientific analysis of these ultra-rare coins rescues the emperor Sponsian from obscurity. Our evidence suggests he ruled Roman Dacia, an isolated gold mining outpost, at a time when the empire was beset by civil wars and the borderlands were overrun by plundering invaders."

The Roman province of Dacia, a territory overlapping with modern-day Romania, was a region prized for its gold mines. Archaeological studies have established that the area was cut off from the rest of the Roman empire in around 260 CE. Surrounded by enemies, Sponsian may have been a local army officer forced to assume supreme command during a period of chaos and civil war, protecting the military and civilian population of Dacia until order was restored, and the province evacuated between 271 and 275 CE.

Coinage has always been an important symbol of power and authority. Recognising this and unable to receive official issues from the mint in Rome, Sponsian seems to have authorised the creation of locally produced coins, some featuring an image of his face, to support a functioning economy in his isolated frontier territory.

When the coins were discovered in the early 18th century, they were thought to be genuine and classed alongside other imitations of Roman coins made beyond the fringes of the empire. However, from the mid-19th century, attitudes changed. Coins from the hoard were dismissed as fakes because of the way they looked. This has been the accepted view until now.

The new study is the first time scientific analysis has been undertaken on any of the Sponsian coins. The research team used powerful microscopes in visible and ultraviolet light, as well as scanning electron microscopy and spectroscopy -- studying how light at different wavelengths is absorbed or reflected -- to study the coins' surface.

Only four coins featuring Sponsian are known to have survived to the present day, all apparently originally from the 1713 hoard. Another is in Brukenthal National Museum in Sibiu, Romania. High magnification microscopic analysis performed there, following the research on the coin at The Hunterian, has revealed similar evidence of authenticity.

Curator of Numismatics at The Hunterian, Jesper Ericsson, said: "This has been a really exciting project for The Hunterian and we're delighted that our findings have inspired collaborative research with museum colleagues in Romania. Not only do we hope that this encourages further debate about Sponsian as a historical figure, but also the investigation of coins relating to him held in other museums across Europe."

The interim manager of the Brukenthal National Museum, Alexandru Constantin Chituță, said: "For the history of Transylvania and Romania in particular, but also for the history of Europe in general, if these results are accepted by the scientific community they will mean the addition of another important historical figure in our history.

"It is a wonderful thing for the Brukenthal National Museum, because the museum in Sibiu, Romania, is the holder of the only known coin belonging to Sponsian from the territory of Romania. I would like to express my gratitude to the colleagues from the Brukenthal Național Museum -- History Museum Altemberger House and especially to the leader of the scientific team, Professor Paul N. Pearson from UCL, for their commitment, hard work and their impressive result."

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Genome studies uncover a new branch in fungal evolution

About 600 seemingly disparate fungi that never quite found a fit along the fungal family tree have been shown to have a common ancestor, according to a University of Alberta-led research team that used genome sequencing to give these peculiar creatures their own classification home.

"They don't have any particular feature that you can see with the naked eye where you can say they belong to the same group. But when you go to the genome, suddenly this emerges," says Toby Spribille, principal investigator on the project and associate professor in the Department of Biological Sciences.

"I like to think of these as the platypus and echidna of the fungal world."

Spribille, Canada Research Chair in Symbiosis, is referring to Australia's famed Linnaean classification system-defying monotremes -- which produce milk and have nipples, but lay eggs -- that were the source of debate as to whether they were even real.

"Though nobody thought our fungi were fake, it's similar because they all look totally different."

Using DNA-based dating techniques, the team found that this new class of fungi, called Lichinomycetes, descended from a single origin 300 million years ago, or 240 million years before the extinction of dinosaurs.

David Díaz-Escandón, who performed the research as part of his PhD thesis, explains that these "oddball" fungi were previously sprinkled across seven different classes -- a high-level grouping that in animals would be equivalent to the groups called mammals or reptiles.

Working with a team of researchers from seven countries to get material from the fungi, he sequenced 30 genomes and found that all classes but one descended from a single origin.

"They were classified, but they were classified into such different parts of the fungal side of the tree of life that people never suspected they were related to each other," says Díaz-Escandón.

These fungi include forms as varied as earth tongues -- eerie tongue-shaped fungi that shoot up vertically out of the ground -- beetle gut microbes, and a fungus found in tree sap in northern Alberta. They also include some unusual lichens that survive in extreme habitats such as South America's Atacama Desert, the driest non-polar desert in the world.

"What is really fascinating is that despite these fungi looking so different, they have a lot in common at the level of their genomes," says Spribille. "Nobody saw this coming."

Based on their genomes, which are small compared with those of other fungi, the team predicts that this group of fungi depend on other organisms for life.

"Their small genomes mean this class of fungi have lost much of their ability to integrate some complex carbohydrates," said Spribille. "When we go back to look at each of these fungi, suddenly we see all of them are in a kind of symbiosis."

He notes the new research will be important to the broader study of fungal evolution, specifically how fungi inherit important biotechnological features such as enzymes that break down plant matter.

The new group also could be a source of new information about past fungal extinctions.

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Scientists convert waste paper into battery parts for smartphones and electric vehicles

Scientists from Nanyang Technological University, Singapore (NTU Singapore) have developed a technique to convert waste paper, from single-use packaging and bags, and cardboard boxes, into a crucial component of lithium-ion batteries.

Through a process called carbonisation which converts paper into pure carbon, the NTU researchers turned the paper's fibres into electrodes, which can be made into rechargeable batteries that power mobile phones, medical equipment, and electric vehicles.

To carbonise the paper, the team exposed the paper to high temperatures, which reduces it to pure carbon, water vapour and oils that can be used for biofuel. As carbonisation takes place in the absence of oxygen, this emits negligible amounts of carbon dioxide, and the process is a greener alternative to disposing of kraft paper through incineration, producing large amounts of greenhouse gasses.

The carbon anodes produced by the research team also demonstrated superior durability, flexibility, and electrochemical properties. Laboratory tests showed that the anodes could be charged and discharged up to 1,200 times, which is at least twice as durable as anodes in current phone batteries. The batteries that use the NTU-made anodes could also withstand more physical stress than their counterparts, absorbing crushing energy up to five times better.

The NTU-developed method also uses less energy-intensive processes and heavy metals compared to current industrial methods of manufacturing battery anodes. As the anode is worth 10 per cent to 15 per cent of the total cost of a lithium-ion battery, this latest method, which uses a low-cost waste material, is expected to also bring down the cost of manufacturing them.

The findings were published in the scientific peer-reviewed journal Additive Manufacturing in October.

Using waste paper as the raw material to produce battery anodes would also ease our reliance on conventional sources for carbon, such as carbonaceous fillers and carbon-yielding binders, which are mined and later processed with harsh chemicals and machinery.

Paper waste, which comprises disposed paper bags cardboard, newspaper, and other paper packaging, accounted for nearly a fifth of the waste generated in Singapore in 2020.

Kraft paper bags, which make up the bulk of Singapore's paper waste, were also found to have large environmental footprints compared to their counterparts made of cotton and plastic, due to their greater contribution to global warming when incinerated and the eco-toxicity potential in producing them, a separate 2020 NTU study found.

The current innovation which presents an opportunity to upcycle waste products and reduce our dependence on fossil fuels, accelerating our transition towards a circular economy, green materials, and clean energy, reflects NTU's commitment to mitigate our impact on the environment, which is one of four humanity's grand challenges that the University seeks to address through its NTU 2025 strategic plan.

Assistant Professor Lai Changquan, from NTU's School of Mechanical & Aerospace Engineering, who led the project, said: "Paper is used in many facets in our daily lives, from gift wrapping and arts and crafts, to a myriad of industrial uses, such as heavy-duty packaging, protective wrapping, and the filling of voids in construction. However, little is done to manage it when it is disposed of, besides incineration, which generates high levels of carbon emissions due to their composition. Our method to give kraft paper another lease of life, funnelling it into the growing need for devices such as electric vehicles and smartphones, would not only help cut down on carbon emissions but would also ease the reliance on mining and heavy industrial methods."

The research team has filed for a patent with NTUitive, NTU's innovation and enterprise company. They are also working towards commercialising their invention.

The recipe for greener battery parts

To produce the carbon anodes, the NTU researchers joined and laser cut several thin sheets of kraft paper to form different lattice geometries, some resembling a spikey piñata. The paper was then heated to 1200°C in a furnace without the presence of oxygen, to convert it into carbon, forming the anodes.

The NTU team attributes the anode's superior durability, flexibility, and electrochemical properties to the arrangement of the paper fibres. They said the combination of strength and mechanical toughness shown by the NTU-made anodes would allow batteries of phones, laptops and automobiles to better withstand shocks from falls and crashes.

Current lithium battery technology relies on internal carbon electrodes that gradually crack and crumble after physical shocks from being dropped, which is one of the main reasons why battery life gets shorter with time.

The researchers say that their anodes, which are hardier than current electrodes used in batteries, would help address this problem and extend the life of batteries in a wide array of uses, from electronics to electric vehicles.

Co-author of the study Mr Lim Guo Yao, a research engineer from NTU's School of Mechanical & Aerospace Engineering, said: "Our anodes displayed a combination of strengths, such as durability, shock absorption, electrical conductivity, which are not found in current materials. These structural and functional properties demonstrate that our kraft paper-based anodes are a sustainable and scalable alternative to current carbon materials, and would find economic value in demanding, high-end, multifunctional applications, such as the nascent field of structural batteries."

Asst Prof Lai added: "Our method converts a common and ubiquitous material -- paper -- into another that is extremely durable and in high demand. We hope that our anodes will serve the world's quickly growing need for a sustainable and greener material for batteries, whose manufacturing and improper waste management have shown to have a negative impact on our environment."

Highlighting the significance of the work done by the NTU research team, Professor Juan Hinestroza from the Department of Human Centered Design of Cornell University, US, who was not involved in the research, said: "As kraft paper is produced in very large quantities and disposed likewise all over the world, I believe that the creative approach pioneered by the researchers at NTU Singapore has a great potential for impact at a global scale. Any discovery that will allow the use of waste as a raw material for high-value products like electrodes and foams is indeed a great contribution. I think that this work may open a new avenue and motivate other researchers to find pathways for the transformation of other cellulose-based substrates, such as textiles and packaging materials, which are being discarded in large quantities all over the globe."

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