Why a high fat diet could reduce the brain's ability to regulate food intake

Regularly eating a high fat/calorie diet could reduce the brain’s ability to regulate calorie intake. New research in rats published in The Journal of Physiology found that after short periods of being fed a high fat/high calorie diet, the brain adapts to react to what is being ingested and reduces the amount of food eaten to balance calorie intake. The researchers from Penn State College of Medicine, US, suggest that calorie intake is regulated in the short-term by cells called astrocytes (large star-shaped cells in the brain that regulate many different functions of neurons in the brain) that control the signalling pathway between the brain and the gut. Continuously eating a high fat/calorie diet seems to disrupt this signalling pathway.

Understanding the brain’s role and the complex mechanisms that lead to overeating, a behaviour that can lead to weight gain and obesity, could help develop therapies to treat it. Obesity is a global public-health concern because it is associated with increased risk of cardiovascular diseases and type 2 diabetes. In England, 63% of adults are considered above a healthy weight and around half of these are living with obesity. One in three children leaving primary school are overweight or obese1.

Dr Kirsteen Browning, Penn State College of Medicine, US, said,

“Calorie intake seems to be regulated in the short-term by astrocytes. We found that a brief exposure (three to five days) of high fat/calorie diet has the greatest effect on astrocytes, triggering the normal signalling pathway to control the stomach. Over time, astrocytes seem to desensitise to the high fat food. Around 10-14 days of eating high fat/calorie diet, astrocytes seem to fail to react and the brain’s ability to regulate calorie intake seems to be lost. This disrupts the signalling to the stomach and delays how it empties.”

Astrocytes initially react when high fat/calorie food is ingested. Their activation triggers the release of gliotransmitters, chemicals (including glutamate and ATP) that excite nerve cells and enable normal signalling pathways to stimulate neurons that control how the stomach works. This ensures the stomach contracts correctly to fill and empty in response to food passing through the digestive system. When astrocytes are inhibited, the cascade is disrupted. The decrease in signalling chemicals leads to a delay in digestion because the stomach doesn’t fill and empty appropriately.

The vigorous investigation used behavioural observation to monitor food intake in rats (N=205, 133 males, 72 females) which were fed a control or high fat/calorie diet for one, three, five or 14 days. This was combined with pharmacological and specialist genetic approaches (both in vivo and in vitro) to target distinct neural circuits. Enabling the researchers to specifically inhibit astrocytes in a particular region of the brainstem (the posterior part of the brain that connects the brain to the spinal cord), so they could assess how individual neurons behaved to studying rats' behaviour when awake.

Human studies will need to be carried out to confirm if the same mechanism occurs in humans. If this is the case, further testing will be required to assess if the mechanism could be safely targeted without disrupting other neural pathways.

The researchers have plans to further explore the mechanism. Dr Kirsteen Browning said.

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A neuro-chip to manage brain disorders

Mahsa Shoaran of the Integrated Neurotechnologies Laboratory in the School of Engineering collaborated with Stéphanie Lacour in the Laboratory for Soft Bioelectronic Interfaces to develop NeuralTree: a closed-loop neuromodulation system-on-chip that can detect and alleviate disease symptoms. Thanks to a 256-channel high-resolution sensing array and an energy-efficient machine learning processor, the system can extract and classify a broad set of biomarkers from real patient data and animal models of disease in-vivo, leading to a high degree of accuracy in symptom prediction.

"NeuralTree benefits from the accuracy of a neural network and the hardware efficiency of a decision tree algorithm," Shoaran says. "It's the first time we've been able to integrate such a complex, yet energy-efficient neural interface for binary classification tasks, such as seizure or tremor detection, as well as multi-class tasks such as finger movement classification for neuroprosthetic applications."

Their results were presented at the 2022 IEEE International Solid-State Circuits Conference and published in the IEEE Journal of Solid-State Circuits, the flagship journal of the integrated circuits community.

Efficiency, scalability, and versatility

NeuralTree functions by extracting neural biomarkers -- patterns of electrical signals known to be associated with certain neurological disorders -- from brain waves. It then classifies the signals and indicates whether they herald an impending epileptic seizure or Parkinsonian tremor, for example. If a symptom is detected, a neurostimulator -- also located on the chip -- is activated, sending an electrical pulse to block it.

Shoaran explains that NeuralTree's unique design gives the system an unprecedented degree of efficiency and versatility compared to the state-of-the-art. The chip boasts 256 input channels, compared to 32 for previous machine-learning-embedded devices, allowing more high-resolution data to be processed on the implant. The chip's area-efficient design means that it is also extremely small (3.48mm2), giving it great potential for scalability to more channels. The integration of an 'energy-aware' learning algorithm -- which penalizes features that consume a lot of power -- also makes NeuralTree highly energy efficient.

In addition to these advantages, the system can detect a broader range of symptoms than other devices, which until now have focused primarily on epileptic seizure detection. The chip's machine learning algorithm was trained on datasets from both epilepsy and Parkinson's disease patients, and accurately classified pre-recorded neural signals from both categories.

"To the best of our knowledge, this is the first demonstration of Parkinsonian tremor detection with an on-chip classifier," Shoaran says.

Self-updating algorithms

Shoaran is passionate about making neural interfaces more intelligent to enable more effective disease control, and she is already looking ahead to further innovations.

"Eventually, we can use neural interfaces for many different disorders, and we need algorithmic ideas and advances in chip design to make this happen. This work is very interdisciplinary, and so it also requires collaborating with labs like the Laboratory for Soft Bioelectronic Interfaces, which can develop state-of-the-art neural electrodes, or labs with access to high-quality patient data."

As a next step, she is interested in enabling on-chip algorithmic updates to keep up with the evolution of neural signals.

"Neural signals change, and so over time the performance of a neural interface will decline. We are always trying to make algorithms more accurate and reliable, and one way to do that would be to enable on-chip updates, or algorithms that can update themselves."

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Meteorites reveal likely origin of Earth's volatile chemicals

By analysing meteorites, Imperial researchers have uncovered the likely far-flung origin of Earth's volatile chemicals, some of which form the building blocks of life.

They found that around half the Earth's inventory of the volatile element zinc came from asteroids originating in the outer Solar System -- the part beyond the asteroid belt that includes the planets Jupiter, Saturn, and Uranus. This material is also expected to have supplied other important volatiles such as water.

Volatiles are elements or compounds that change from solid or liquid state into vapour at relatively low temperatures. They include the six most common elements found in living organisms, as well as water. As such, the addition of this material will have been important for the emergence of life on Earth.

Prior to this, researchers thought that most of Earth's volatiles came from asteroids that formed closer to the Earth. The findings reveal important clues about how Earth came to harbour the special conditions needed to sustain life.

Senior author Professor Mark Rehka?mper, of Imperial College London's Department of Earth Science and Engineering, said: "Our data show that about half of Earth's zinc inventory was delivered by material from the outer Solar System, beyond the orbit of Jupiter. Based on current models of early Solar System development, this was completely unexpected."

Previous research suggested that the Earth formed almost exclusively from inner Solar System material, which researchers inferred was the predominant source of Earth's volatile chemicals. In contrast, the new findings suggest the outer Solar System played a bigger role than previously thought.

Professor Rehka?mper added: "This contribution of outer Solar System material played a vital role in establishing the Earth's inventory of volatile chemicals. It looks as though without the contribution of outer Solar System material, the Earth would have a much lower amount of volatiles than we know it today -- making it drier and potentially unable to nourish and sustain life."

The findings are published today in Science.

To carry out the study, the researchers examined 18 meteorites of varying origins -- eleven from the inner Solar System, known as non-carbonaceous meteorites, and seven from the outer Solar System, known as carbonaceous meteorites.

For each meteorite they measured the relative abundances of the five different forms -- or isotopes -- of zinc. They then compared each isotopic fingerprint with Earth samples to estimate how much each of these materials contributed to the Earth's zinc inventory. The results suggest that while the Earth only incorporated about ten per cent of its mass from carbonaceous bodies, this material supplied about half of Earth's zinc.

The researchers say that material with a high concentration of zinc and other volatile constituents is also likely to be relatively abundant in water, giving clues about the origin of Earth's water.

First author on the paper Rayssa Martins, PhD candidate at the Department of Earth Science and Engineering, said: "We've long known that some carbonaceous material was added to the Earth, but our findings suggest that this material played a key role in establishing our budget of volatile elements, some of which are essential for life to flourish."

Next the researchers will analyse rocks from Mars, which harboured water 4.1 to 3 billion years ago before drying up, and the Moon. Professor Rehka?mper said: "The widely held theory is that the Moon formed when a huge asteroid smashed into an embryonic Earth about 4.5 billion years ago. Analysing zinc isotopes in moon rocks will help us to test this hypothesis and determine whether the colliding asteroid played an important part in delivering volatiles, including water, to the Earth."

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What crocodile DNA reveals about the Ice Age

What drives crocodile evolution? Is climate a major factor or changes in sea levels? Determined to find answers to these questions, researchers from McGill University discovered that while changing temperatures and rainfall had little impact on the crocodiles' gene flow over the past three million years, changes to sea levels during the Ice Age had a different effect.

"The American crocodile tolerates huge variations in temperature and rainfall. But about 20,000 years ago - when much of the world's water was frozen, forming the vast ice sheets of the last glacial maximum - sea levels dropped by more than 100 metres. This created a geographical barrier that separated the gene flow of crocodiles in Panama," says postdoctoral fellow José Avila-Cervantes, working under the supervision of McGill professor Hans Larsson.

The researchers point out that the crocodiles are good swimmers, but they can't travel long distances on land. As a result, the Caribbean and Pacific crocodile populations were isolated from each other, and consequently have undergone different genetic mutations.

The team compared the climate tolerance of living populations of American crocodiles (Crocodylus acutus) to the paleoclimate estimates for the region over the past 3 million years - the time span of extreme climate variation during the Ice Age.

"This is one of the first times Ice Age effects have been found in a tropical species. It's exciting to discover effects of the last Ice Age glaciation still resonate in the genomes of Pacific and Caribbean American crocodiles today," says Larsson, Professor of Biology at the Redpath Museum of McGill University.

"Discovering that these animals would have easily tolerated the climate swings of the Ice Age speaks to their resilience over geological time. Only humans in recent decades of hunting and land development seem to really affect crocodiles," he says. The findings offer new insight into how environmental drivers affect genetic evolution and where conservation efforts of particular crocodile populations in Panama should be focused.

From Science Daily

New geosciences study shows Triassic fossils that reveal origins of living amphibians

The smallest of newly found fossils can upend what paleontologists know about our history.

A team of paleontologists from Virginia Tech and the U.S. Petrified Forest National Park, among others, have discovered the first "unmistakable" Triassic-era caecilian fossil -- the oldest-known caecilian fossils -- thus extending the record of this small, burrowing animal by roughly 35 million years. The find also fills a gap of at least 87 million years in the known historical fossil record of the amphibian-like creature.

The fossil was first co-discovered by Ben Kligman, a doctoral student in the Department of Geosciences, part of the Virginia Tech College of Science, at Arizona's Petrified Forest National Park during a dig in 2019. Named by Kligman as Funcusvermis gilmorei, the fossil extends the history of caecilians 35 million years back to Triassic Period, roughly 250 million to 200 million years ago.

Prior to this new study, published today in the journal Nature, only 10 fossil caecilian occurrences were known, dating back to the Early Jurassic Period, about 183 million years ago. However, previous DNA studies estimated evolutionary origins of caecilians back to the Carboniferous or Permian eras, some 370 million to 270 million years ago, according to Kligman, marking that 87-million-year gap. However, no such fossils had been found.

"The discovery of the oldest caecilian fossils highlights the crucial nature of new fossil evidence. Many of the biggest outstanding questions in paleontology and evolution cannot be resolved without fossils like this," said Kligman, who previously discovered a 220-million-year-old species of cynodont or stem-mammal, a precursor of modern-day mammals. "Fossil caecilians are extraordinarily rare, and they are found accidentally when paleontologists are searching for the fossils of other more common animals. Our discovery of one was totally unexpected, and it transformed the trajectory of my scientific interests."

The discovery of the fossils was made in 2019 by Kligman and Petrified Forest National Park student intern Xavier Jenkins, now a Ph.D. student at Idaho State University, while the duo was processing fossiliferous sediment from the park's nicknamed Thunderstorm Ridge via a microscope. Funcusvermis was found in a layer of the Chinle Formation dated to approximately 220 million years ago, when Arizona was positioned near the equator at the central part of the supercontinent Pangaea, Kligman said. This region at the time was subject to a hot, humid climate. Today, Arizona is still hot, but has low humidity.

"Seeing the first jaw under the microscope, with its distinctive double row of teeth, sent chills down my back," Kligman said. "We immediately knew it was a caecilian, the oldest caecilian fossil ever found, and a once-in-a-lifetime discovery."

Previous to this find, the 87-million-year gap in the fossil record hid the early evolutionary history of caecilians, leading to a decades-long debate amongst scientists over the relationships of caecilians to their amphibian relatives, frogs and salamanders.

"Funcusvermis extends the humid equatorial pattern of occurrence seen in all known fossil and living caecilians, suggesting that the biogeographic history of caecilians has been guided by restriction to these ecological settings, likely due to physiological constraints linked to humidity, and constrained by the drift of continental plates into and out of the humid-equatorial zone after the fragmentation of Pangaea," Kligman said.

Modern caecilians are limbless amphibians with cylindrical bodies with a compact, bullet-shaped skull that helps them burrow underground. Now exclusively home to South and Central America, Africa, and southern Asia, caecilians spend their lives burrowing in leaf-litter or soil searching for prey such as worms and insects. This underground existence has made studying caecilians difficult for scientists. Kligman, tongue in cheek, describes modern caecilians as an "eyeless sock puppet with the body of a worm."

Funcusvermis actually shares skeletal features related more with early frog and salamander fossils, strengthening evidence for a shared origin and close evolutionary relationship between caecilians and these two groups. Funcusvermis also shares skeletal features with an ancient group of amphibians known to paleontologists as dissorophoid temnospondyls. Kligman adds, "Unlike living caecilians, Funcusvermis lacks many adaptations associated with burrowing underground, indicating a slower acquisition of features associated with an underground lifestyle in the early stages of caecilian evolution."

Name that tune

Now, here's the fun part: The genus name 'Funcusvermis' was inspired by the Ohio Players' 1972 song "Funky Worm" from their album Pleasure, a favorite song of the authors that was often played while excavating fossils at Thunderstorm Ridge. 'Funcus' is derived from the Latinized form of the English word Funky for the upbeat, rhythmic form of dance music, while 'vermis' is derived from the Latin word for worm. (It's an excellent song, by the way. Instant earworm, so to speak.)

The species name, gilmorei, honors Ned Gilmore, the collections manager at the Academy of Natural Sciences of Philadelphia's Drexel University. (Kligman is from Philadelphia and volunteered with Gilmore's herpetology wet collection as an undergraduate student. "He was an important mentor who helped inspire my interest in fossils and amphibians," Kligman said.)

Co-authors on the study include Michelle Stocker, an assistant professor, and Sterling Nesbitt, an associate professor, in the Virginia Tech Department of Geosciences and members of the Global Change Center that is part of the Fralin Life Sciences Institute. Other authors include Adam Marsh, lead paleontologist; Matthew Smith, museum curator; and William Parker, chief of science and resource management, all at the Petrified Forest National Park; and Bryan Gee, postdoctoral fellow at the University of Washington's Burke Museum and Department of Biology.

"As the eponymous song says, it's the funkiest worm in the world," Marsh quipped.

Stocker added, "What we collect really determines what we can say about which animals that were present, how many of them there were, and what they looked like. Without using these methods for fossil collection and analysis we would be missing out on knowing so many important aspects of this Triassic ecosystem. Now that we have a search image of what bones to look for and how to look for them, it will be exciting to see what other fossil localities preserve these early lissamphibians."

Nesbitt said finds such as this can reset the game board on paleontology, in the best sense of the phrase. "This find clearly demonstrates that some fossils that you can barely see can greatly change our understanding of entire groups that you can see today," he said.

What's happened since 2019

At the Petrified Forest National Park, where the initial discovery was found in 2019, the lower jaws of at least 70 individuals of Funcusvermis have been recovered as of summer 2022, making the area "the most abundant fossil caecilian-producing bonebed ever discovered," Kligman said.

Only a handful of bones of Funcusvermis have been found, including upper and lower jaws, a vertebra, and part of a hind-limb, Kligman said. All of the found bones were disarticulated, not as complete skeletons. Without complete skeletons, Kligman and his fellow researchers cannot exactly determine the body length of Funcusvermis, but inferences from isolated elements, such as the lower jaw being less than a quarter of an inch long, indicate that Funcusvermis was a tiny animal.

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Mercury helps to detail Earth's most massive extinction event

The Latest Permian Mass Extinction (LPME) was the largest extinction in Earth's history to date, killing between 80-90% of life on the planet, though finding definitive evidence for what caused the dramatic changes in climate has eluded experts.

An international team of scientists, including UConn Department of Earth Sciences researchers Professor and Department Head Tracy Frank and Professor Christopher Fielding, are working to understand the cause and how the events of the LPME unfolded by focusing on mercury from Siberian volcanoes that ended up in sediments in Australia and South Africa. The research has been published in Nature Communications.

Though the LPME happened over 250 million years ago, there are similarities to the major climate changes happening today, explains Frank:

"It's relevant to understanding what might happen on earth in the future. The main cause of climate change is related to a massive injection of carbon dioxide into the atmosphere around the time of the extinction, which led to rapid warming."

In the case of the LPME, it is widely accepted that the rapid warming associated with the event is linked to massive volcanism occurring at a huge deposit of lava called the Siberian Traps Large Igneous Province (STLIP), says Frank, but direct evidence was still lacking.

Volcanos leave helpful clues in the geological record. With the outpouring of lava, there was also a huge quantity of gases released, such as CO2 and methane, along with particulates and heavy metals that were launched into the atmosphere and deposited around the globe.

"However, it's hard to directly link something like that to the extinction event," says Frank. "As geologists, we're looking for a signature of some kind -- a smoking gun -- so that we can absolutely point to the cause."

In this case, the smoking gun the researchers focused on was mercury, one of the heavy metals associated with volcanic eruptions. The trick is finding areas where that record still exists.

Frank explains there is a continuous record of the earth's history contained in sediments in marine environments which acts almost like a tape recorder because deposits are quickly buried and protected. These sediments yield an abundance of data about the extinction and how it unfolded in the oceans. On land, it is more difficult to find such well-preserved records from this time period.

To illustrate this, Frank uses Connecticut as an example: the state is rich with 400-500-million-year-old metamorphic rocks at or near the surface, with a covering of glacial deposits dating to around 23,000 years ago.

"There's a big gap in the record here. You have to be lucky to preserve terrestrial records and that's why they aren't as well studied, because there are fewer of them out there," says Frank.

Not all terrains around the world have such massive gaps in the geologic record, and previous studies of the LPME have focused primarily on sites found in the northern hemisphere. However, the Sydney Basin in Eastern Australia and the Karoo Basin in South Africa are two areas in the southern hemisphere that happen to have an excellent record of the event, and are areas Frank and Fielding have studied previously. A colleague and co-author, Jun Shen from the State Key Laboratory of Geological Processes and Mineral Resources at the China University of Geosciences, reached out and connected with Frank, Fielding, and other co-authors for samples, with hopes to analyze them for mercury isotopes.

Shen was able to analyze the mercury isotopes in the samples and tie all the data together says Frank.

"It turns out that volcanic emissions of mercury have a very specific isotopic composition of the mercury that accumulated at the extinction horizon. Knowing the age of these deposits, we can more definitively tie the timing of the extinction to this massive eruption in Siberia. What is different about this paper is we looked not only at mercury, but the isotopic composition of the mercury from samples in the high southern latitudes, both for the first time."

This definitive timing is something that scientists have been working on refining, but as Fielding points out, the more that we learn, the more complicated it gets.

"As a starting point, geologists have pinpointed the timing of the major extinction event at 251.9 million years with a high degree of precision from radiogenic isotope dating methods. Researchers know that is when the major extinction event happened in the marine environment and it was just assumed that the terrestrial extinction event happened at the same time."

In Frank and Fielding's previous research, they found that the extinction event on land happened 200-600,000 years earlier, however.

"That suggests that the event itself wasn't just one big whammy that happened instantaneously. It wasn't just one very bad day on Earth, so to speak, it took some time to build and this feeds in well into the new results because it suggests the volcanism was the root cause," says Fielding. "That's just the first impact of the biotic crisis that happened on land, and it happened early. It took time to be transmitted into the oceans. The event 251.9 million years ago was the major tipping point in environmental conditions in the ocean that had deteriorated over some time."

Retracing the events relies on knowledge from many different geologists all specializing in different methods, from sedimentology, geochemistry, paleontology, and geochronology, says Frank.

Read more at Science Daily

New AI tool makes speedy gene-editing possible

An artificial intelligence program may enable the first simple production of customizable proteins called zinc fingers to treat diseases by turning genes on and off.

The researchers at NYU Grossman School of Medicine and the University of Toronto who designed the tool say it promises to accelerate the development of gene therapies on a large scale.

Illnesses including cystic fibrosis, Tay-Sachs disease, and sickle cell anemia are caused by errors in the order of DNA letters that encode the operating instructions for every human cell. Scientists can in some cases correct these mistakes with gene editing methods that rearrange these letters.

Other conditions are caused, not by a mistake in the code itself, but by problems in how the cellular machinery reads DNA (epigenetics). A gene, which provides the recipe for a particular protein, often partners with molecules called transcription factors that tell the cell how much of that protein to make. When this process goes awry, over- or underactive genes contribute to diabetes, cancer, and neurological disorders. As a result, researchers have been exploring ways to restore normal epigenetic activity.

One such technique is zinc-finger editing, which can both change and control genes. Among the most abundant protein structures in the human body, zinc fingers can guide DNA repair by grabbing onto scissor-like enzymes and directing them to cut faulty segments out of the code.

Similarly, zinc fingers can also hook onto transcription factors and pull them toward a gene segment in need of regulation. By customizing these instructions, genetic engineers can tailor any gene's activity. A drawback, however, is that artificial zinc fingers are challenging to design for a specific task. Since these proteins attach to DNA in complex groups, researchers would need to be able to tell -- out of countless possible combinations -- how every zinc finger interacts with its neighbor for each desired genetic change.

The study authors' new technology, called ZFDesign, overcomes this obstacle by using artificial intelligence (AI) to model and design these interactions. The model is based on data generated by the screen of nearly 50 billion possible zinc finger-DNA interactions in the researchers' labs. A report on the tool is publishing online Jan. 26 in the journal Nature Biotechnology.

"Our program can identify the right grouping of zinc fingers for any modification, making this type of gene editing faster than ever before," says study lead author David Ichikawa, PhD, a former graduate student at NYU Langone Health.

Ichikawa notes that zinc-finger editing offers a potentially safer alternative to CRISPR, a key gene-editing technology with applications that range from finding new ways to kill cancer cells to designing more nourishing crops. Unlike the entirely human-derived zinc fingers, CRISPR, which stands for clustered regularly interspaced short palindromic repeat, relies on bacterial proteins to interact with genetic code. These "foreign" proteins could trigger patients' immune defense systems, which may attack them like any other infection and lead to dangerous inflammation.

The study authors add that besides posing a lower immune risk, the small size of zinc-finger tools may also provide more flexible gene therapy techniques compared with CRISPR by enabling more ways to deliver the tools to the right cells in patients.

"By speeding up zinc-finger design coupled with their smaller size, our system paves the way for using these proteins to control multiple genes at the same time," says study senior author Marcus Noyes, PhD. "In the future, this approach may help correct diseases that have multiple genetic causes, such as heart disease, obesity, and many cases of autism."

To test the computer's AI design code, Noyes and his team used a customized zinc finger to disrupt the coding sequence of a gene in human cells. In addition, they built several zinc fingers that successfully reprogrammed transcription factors to bind near a target gene sequence and turn up or down its expression, demonstrating that their technology can be used for epigenetic changes.

Noyes, an assistant professor in the Department of Biochemistry and Molecular Pharmacology at NYU Langone, cautions that, while promising, zinc fingers can be difficult to control. Since they are not always specific to a single gene, some combinations can affect DNA sequences beyond a particular target, leading to unintended changes in genetic code.

As a result, Noyes says the team next plans to refine their AI program so it can build more precise zinc-finger groupings that only prompt the desired edit. Noyes is also a member of NYU Langone's Institute for System Genetics.

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How a 3 cm glass sphere could help scientists understand space weather

Solar flares and other types of space weather can wreak havoc with spaceflight and with telecommunications and other types of satellites orbiting the Earth. But, to date, scientists' ability to research ways to overcome that challenge has been severely limited. That's because experiments they conduct in laboratories here on Earth are affected by gravity in ways that are so different from conditions in space.

But a new study by UCLA physicists could, at last, help conquer that issue -- which could be a big step toward safeguarding humans (and equipment) during space expeditions, and to ensuring the proper functioning of satellites. The paper is published in Physical Review Letters.

The UCLA researchers effectively reproduced the type of gravity that exists on or near stars and other planets inside of a glass sphere measuring 3 centimeters in diameter (about 1.2 inches). To do so, they used sound waves to create a spherical gravitational field and generate plasma convection -- a process in which gas cools as it nears the surface of a body and then reheats and rises again as it nears the core -- creating a fluid current that in turn generates a magnetic current.

The achievement could help scientists overcome the limiting role of gravity in experiments that are intended to model convection that occurs in stars and other planets.

"People were so interested in trying to model spherical convection with laboratory experiments that they actually put an experiment in the space shuttle because they couldn't get a strong enough central force field on the ground," said Seth Putterman, a UCLA physics professor and the study's senior author. "What we showed is that our system of microwave-generated sound produced gravity so strong that Earth's gravity wasn't a factor. We don't need to go into space to do these experiments anymore."

UCLA researchers used microwaves to heat sulfur gas to 5,000 degrees Fahrenheit inside the glass sphere. The sound waves inside the ball acted like gravity, constraining movement of the hot, weakly ionized gas, known as plasma, into patterns that resemble the currents of plasma in stars.

"Sound fields act like gravity, at least when it comes to driving convection in gas," said John Koulakis, a UCLA project scientist and the study's first author. "With the use of microwave-generated sound in a spherical flask of hot plasma, we achieved a gravity field that is 1,000 times stronger than Earth's gravity."

On Earth's surface, hot gas rises because gravity holds denser, colder gas closer to the planet's center.

Indeed, the researchers found that hot, bright gas near the outer half of the sphere also moved outward toward the walls of the sphere. The strong, sustained gravity generated turbulence that resembled that seen near the Sun's surface. In the inner half of the sphere, the acoustic gravity changed direction and pointed outward, which causes hot gas to sink to the center. In the experiment, acoustic gravity naturally held the hottest plasma at the center of the sphere, where it also occurs in stars.

The ability to control and manipulate plasma in ways that mirror solar and planetary convection will help researchers understand and predict how solar weather affects spacecraft and satellite communications systems. Last year, for example, a solar storm knocked out 40 SpaceX satellites. The phenomenon has also been problematic for military technology: the formation of turbulent plasma around hypersonic missiles, for example, can interfere with weapons systems communications.

Read more at Science Daily

Traffic pollution impairs brain function

A new study by researchers at the University of British Columbia and the University of Victoria has shown that common levels of traffic pollution can impair human brain function in only a matter of hours.

The peer-reviewed findings, published in the journal Environmental Health, show that just two hours of exposure to diesel exhaust causes a decrease in the brain's functional connectivity -- a measure of how The study provides the first evidence in humans, from a controlled experiment, of altered brain network connectivity induced by air pollution.

"For many decades, scientists thought the brain may be protected from the harmful effects of air pollution," said senior study author Dr. Chris Carlsten, professor and head of respiratory medicine and the Canada Research Chair in occupational and environmental lung disease at UBC. "This study, which is the first of its kind in the world, provides fresh evidence supporting a connection between air pollution and cognition."

For the study, the researchers briefly exposed 25 healthy adults to diesel exhaust and filtered air at different times in a laboratory setting. Brain activity was measured before and after each exposure using functional magnetic resonance imaging (fMRI).

The researchers analyzed changes in the brain's default mode network (DMN), a set of inter-connected brain regions that play an important role in memory and internal thought. The fMRI revealed that participants had decreased functional connectivity in widespread regions of the DMN after exposure to diesel exhaust, compared to filtered air.

"We know that altered functional connectivity in the DMN has been associated with reduced cognitive performance and symptoms of depression, so it's concerning to see traffic pollution interrupting these same networks," said Dr. Jodie Gawryluk, a psychology professor at the University of Victoria and the study's first author. "While more research is needed to fully understand the functional impacts of these changes, it's possible that they may impair people's thinking or ability to work."

Taking steps to protect yourself

Notably, the changes in the brain were temporary and participants' connectivity returned to normal after the exposure. Dr. Carlsten speculated that the effects could be long lasting where exposure is continuous. He said that people should be mindful of the air they're breathing and take appropriate steps to minimize their exposure to potentially harmful air pollutants like car exhaust.

"People may want to think twice the next time they're stuck in traffic with the windows rolled down," said Dr. Carlsten. "It's important to ensure that your car's air filter is in good working order, and if you're walking or biking down a busy street, consider diverting to a less busy route."

While the current study only looked at the cognitive impacts of traffic-derived pollution, Dr. Carlsten said that other products of combustion are likely a concern.

"Air pollution is now recognized as the largest environmental threat to human health and we are increasingly seeing the impacts across all major organ systems," says Dr. Carlsten. "I expect we would see similar impacts on the brain from exposure to other air pollutants, like forest fire smoke. With the increasing incidence of neurocognitive disorders, it's an important consideration for public health officials and policymakers."

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Recyclable mobile phone batteries a step closer with rust-busting invention

Mobile phone batteries with a lifetime up to three times longer than today's technology could be a reality thanks to an innovation led by engineers at RMIT University.

Rather than disposing of batteries after two or three years, we could have recyclable batteries that last for up to nine years, the team says, by using high-frequency sound waves to remove rust that inhibits battery performance.

Only 10% of used handheld batteries, including for mobile phones, are collected for recycling in Australia, which is low by international standards. The remaining 90% of batteries go to landfill or are disposed of incorrectly, which causes considerable damage to the environment.

The high cost of recycling lithium and other materials from batteries is a major barrier to these items being reused, but the team's innovation could help to address this challenge.

The team are working with a nanomaterial called MXene, a class of materials that they say promises to be an exciting alternative to lithium for batteries in the future.

Leslie Yeo, Distinguished Professor of Chemical Engineering and lead senior researcher, said MXene was similar to graphene with high electrical conductivity.

"Unlike graphene, MXenes are highly tailorable and open up a whole range of possible technological applications in the future," said Yeo from RMIT's School of Engineering.

The big challenge with using MXene was that it rusted easily, thereby inhibiting electrical conductivity and rendering it unusable, he said.

"To overcome this challenge, we discovered that sound waves at a certain frequency remove rust from MXene, restoring it to close to its original state," Yeo said.

The team's innovation could one day help to revitalise MXene batteries every few years, extending their lifetime up to three times, he said.

"The ability to prolong the shelf life of MXene is critical to ensuring its potential to be used for commercially viable electronic parts," Yeo said.

The research is published in Nature Communications.

How the innovation works

Co-lead author Mr Hossein Alijani, a PhD candidate, said the greatest challenge with using MXene was the rust that forms on its surface in a humid environment or when suspended in watery solutions.

"Surface oxide, which is rust, is difficult to remove especially on this material, which is much, much thinner than a human hair," said Alijani from RMIT's School of Engineering.

"Current methods used to reduce oxidation rely on the chemical coating of the material, which limits the use of the MXene in its native form.

"In this work, we show that exposing an oxidised MXene film to high-frequency vibrations for just a minute removes the rust on the film. This simple procedure allows its electrical and electrochemical performance to be recovered."

The potential applications of the team's work

The team says their work to remove rust from Mxene opens the door for the nanomaterial to be used in a wide range of applications in energy storage, sensors, wireless transmission and environmental remediation.

Associate Professor Amgad Rezk, one of the lead senior researchers, said the ability to quickly restore oxidised materials to an almost pristine state represented a gamechanger in terms of the circular economy.

"Materials used in electronics, including batteries, generally suffer deterioration after two or three years of use due to rust forming," said Rezk from RMIT's School of Engineering.

"With our method, we can potentially extend the lifetime of battery components by up to three times."

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