Decades of research have revealed trends in how the shapes and structures of different surfaces affect water's freezing point. In an earlier study on ice-nucleating proteins within bacteria, researchers found that the distances between the groups of proteins could impact the temperature at which ice formed. There were distances that were very favorable for ice formation, and distances that were completely opposite.

Similar trends had been observed for other surfaces, but no mathematical explanation had been found.

Researchers now  gathered hundreds of previously reported measurements on how the angles between microscopic bumps on a surface affected water's freezing temperature.  They then tested theoretical models against the data. They used the models to consider factors that would encourage ice crystal formation, such as how strongly water binds to the surfaces and angles between structural features.

In the end, they identified a mathematical expression that shows that certain angles between surface features makes it easier for water molecules to gather and crystallize at relatively warmer temperatures. 

They say their model can help design materials with surfaces that would make ice form more efficiently with minimal energy input. Examples include snow or ice makers, or surfaces that are suitable for cloud seeding.

The researchers plan to use this model to return to their studies of ice-nucleating proteins in bacteria.

https://www.acs.org/pressroom/presspacs/2024/march/new-model-clarif...

Researchers find evidence of 68 'forever chemicals' in food packaging around the world

A team of environmental scientists with the Food Packaging Forum Foundation, based in Zürich, has found evidence of 68 "forever chemicals" in food packaging used around the world. For their study, published in the journal Environmental Science & Technology, the group mapped evidence of per- and polyfluoroalkyl substances (PFASs) in food contact materials using information from databases.

PFASs are a group of manmade chemical compounds that are known as "forever" chemicals because it takes them so long to break down in the environment. To date, approximately 4,730 distinct PFASs have been created. Manufacturers began using them several decades ago for their water-resistance properties. They have typically been used in such products as nonstick stain-resistant fabrics, cookware, water-repellent clothing, carpeting, cosmetics, firefighting foams, electronics and food packaging.

Over the past several decades, many PFASs have been found to have adverse health impacts on animals, including humans. Because of that, many of them have been banned around the world.

In this new study, the research team looked into the use of PFASs in food packaging around the world, as recent research has shown that the compounds can migrate into the food.

The researchers collected records from the FCCmigex database involving food packaging and any known PFAS. They found 68 of the compounds, 61 of which have been specifically banned from use in such packaging. They were only able to find potential hazards for just 57% of the compounds they found.

In looking at the compounds they found in the packaging, the research team notes that little evidence is available to explain how or why they wound up where they did. They suggest a comprehensive review of packaging be undertaken and new rules and a means for enforcing them be established.

Drake W. Phelps et al, Per- and Polyfluoroalkyl Substances in Food Packaging: Migration, Toxicity, and Management Strategies, Environmental Science & Technology (2024). DOI: 10.1021/acs.est.3c03702

Neuralink shows quadriplegic playing chess with brain implant

Neuralink recently streamed a video of its first human patient playing computer chess with his mind and talking about the brain implant making that possible.

How cells in plant leaves organize themselves to ensure optimal area for photosynthesis

Plant leaves need a large surface area to capture sunlight for photosynthesis. Researchers  have now discovered which genetic mechanisms control leaves' growth into a flat structure capable of efficiently capturing sunlight.

A kind of built-in GPS informs each cell about its relative position in the growing leaf. The order corresponds to a biological concept of self-organization.

When cells divide and multiply, the result is usually a clump of cells. So researchers wanted to know how, in the case of a leaf, cell division leads to a large flat area.

To this end, a team of mathematicians and experimental biologists worked together to track the processes using computer models, methods of molecular genetics, and imaging techniques on living organisms.

The basis of such pattern formation is polarity; that is, the ability to distinguish, in this case, between top and bottom. It is usually created by a concentration gradient of a substance, called morphogen, that is low on one side and higher on the other.

The team discovered that "small RNAs" play a decisive role in controlling the growing leaf. As mobile messengers, they are used for communication between the cells and help the cells to perceive their relative position to each other in the structure—like a GPS. In addition, the small RNAs transmit information that coordinates which genes need to be activated or inhibited on the top and bottom side to give the leaf the right shape and function.

This regulatory mechanism works autonomously in the growing leaf; there is no central control in the plant.

The small RNA molecules in the cells of the growing leaf set in motion a genetic process that enables the cells to perceive and interpret their environment. The genes' activities are coordinated among the cells in such a way that each leaf is divided in a sharply defined top and bottom part that form a perfectly flat canvas for photosynthesis.

Emanuele Scacchi et al, A diffusible small-RNA-based Turing system dynamically coordinates organ polarity, Nature Plants (2024). DOI: 10.1038/s41477-024-01634-x

DNA attached to nanoparticles found to contribute to lupus symptoms

Autoimmune diseases are mysterious. It wasn't until the 1950s that scientists realized that the immune system could harm the organs of its own body. Even today, the fundamental causes and inner workings of most autoimmune diseases remain poorly understood, limiting the treatment options for many of these conditions.

Over the past several years, however, research has found clues for how autoimmune diseases might arise. This research has shown that DNA attached to small particles within the bloodstream is a likely culprit involved in many autoimmune diseases, especially systemic lupus erythematosus, or just lupus for short, which primarily affects young women and can cause kidney damage.

However, due to the large variety in sizes of both particles and DNA in the blood, testing to what extent and under what circumstances these DNA-particle combinations play a role in disease has been extremely difficult.

Researchers at Duke University have now developed a way to systematically test how these DNA-bound particles interact with the immune system. By using tiny particles of specific sizes, attaching DNA strands of certain lengths and exposing the resulting complexes to immune cells in a lab dish, the researchers show a better fundamental understanding of these diseases may be possible.

The results were published in the Proceedings of the National Academy of Sciences.

This new approach identified the cellular pathway that causes the harmful response to these hybrid particles, and showed that DNA bound to the surfaces of nanoparticles is protected from being degraded by enzymes.

While DNA is usually locked away within a cell's nucleus, it often gets into the bloodstream when cells die or are attacked by viruses and bacteria. While most so-called "cell-free DNA" only lasts minutes before being broken down by the body, in some people and situations, it can persist for much longer. In recent work, high levels of cell-free DNA have been closely related to the severity of lupus symptoms, and many doctors are now testing ways to use it to monitor disease activity.

Cell-free DNA may escape elimination largely by forming complexes with other molecules or attaching itself to naturally occurring particles. Depending on the origin of the DNA, it can range in length from a few hundred base pairs to several thousand. And the particles it can attach to range from 100 to 1000 nanometers in diameter.

The first important observation the team made was that DNA attached to nanoparticles was protected from degrative enzymes and that larger nanoparticles provided more protection.

The researchers think the enzymes might not be able to access the DNA to destroy it because of the shape the DNA makes with the surface of the nanoparticle.

The results showed that the macrophages responded to all types of DNA-particle complexes by producing inflammatory signals for other cells to follow, a hallmark of many autoimmune diseases.

This approach gives researchers a way to drill down and pinpoint factors that they wouldn't be able to with a purely biological system.

 Faisal Anees et al, DNA corona on nanoparticles leads to an enhanced immunostimulatory effect with implications for autoimmune diseases, Proceedings of the National Academy of Sciences (2024). DOI: 10.1073/pnas.2319634121

Signs of life detectable in single ice grain emitted from extraterrestrial moons, experimental setup shows

The ice-encrusted oceans of some of the moons orbiting Saturn and Jupiter are leading candidates in the search for extraterrestrial life. A new lab-based study  shows that individual ice grains ejected from these planetary bodies may contain enough material for instruments headed there in the fall to detect signs of life, if such life exists.

For the first time scientists have shown that even a tiny fraction of cellular material could be identified by a mass spectrometer onboard a spacecraft. These results give researchers more confidence that using upcoming instruments, they will be able to detect lifeforms similar to those on Earth, which we increasingly believe could be present on ocean-bearing moons. 

Researchers used an experimental setup that sends a thin beam of liquid water into a vacuum, where it disintegrates into droplets. They then used a laser beam to excite the droplets and mass spectral analysis to mimic what instruments on the space probe will detect.

Newly published results show that instruments slated to go on future missions, like the SUrface Dust Analyzer onboard Europa Clipper, can detect cellular material in one out of hundreds of thousands of ice grains. 

Part 1

The study focused on Sphingopyxis alaskensis, a common bacterium in waters off Alaska. While many studies use the bacterium Escherichia coli as a model organism, this single-celled organism is much smaller, lives in cold environments, and can survive with few nutrients. All these things make it a better candidate for potential life on the icy moons of Saturn or Jupiter.

They are extremely small, so they are in theory capable of fitting into ice grains that are emitted from an ocean world like Enceladus or Europa.

Results show that the instruments can detect this bacterium, or portions of it, in a single ice grain. Different molecules end up in different ice grains. The new research shows that analyzing single ice grains, where biomaterial may be concentrated, is more successful than averaging across a larger sample containing billions of individual grains.

A recent study led by the same researchers showed evidence of phosphate on Enceladus. This planetary body now appears to contain energy, water, phosphate, other salts and carbon-based organic material, making it increasingly likely to support lifeforms similar to those found on Earth.

The authors hypothesize that if bacterial cells are encased in a lipid membrane, like those on Earth, then they would also form a skin on the ocean's surface. On Earth, ocean scum is a key part of sea spray that contributes to the smell of the ocean. On an icy moon where the ocean is connected to the surface (e.g., through cracks in the ice shell), the vacuum of outer space would cause this subsurface ocean to boil. Gas bubbles rise through the ocean and burst at the surface, where cellular material gets incorporated into ice grains within the plume.

In the paper published by the researchers,  they described a plausible scenario for how bacterial cells can, in theory, be incorporated into icy material that is formed from liquid water on Enceladus or Europa and then gets emitted into space.

The SUrface Dust Analyzer onboard Europa Clipper will be higher-powered than instruments on past missions. This and future instruments also will for the first time be able to detect ions with negative charges, making them better suited to detecting fatty acids and lipids.

Fabian Klenner, How to Identify Cell Material in a Single Ice Grain Emitted from Enceladus or Europa, Science Advances (2024). DOI: 10.1126/sciadv.adl0849. www.science.org/doi/10.1126/sciadv.adl0849

Part 2

The dissimilar smells of babies and teenagers

A team of aroma chemists has uncovered the reasons for the dissimilar smells between babies and teenagers. The study is published in the journal Communications Chemistry.

Prior research and anecdotal evidence have shown that babies have a pleasant smell, often described as sweet. Teenagers, on the other hand, especially males, have often been described as smelling less pleasant. In this new effort, the research team sought to find out what causes the difference.

The researchers recruited the parents of 18 children aged up to 3 years old to wash the youngsters with a fragrance-free gel and to take swap samples of the armpits of their pajamas prior to sleep. They did the same with 18 teenagers between the ages of 14 and 18. All the cotton pads were then collected and analyzed in a lab setting.

The research team used mass spectrometry to identify the chemical compounds in the pads, and used gas chromatography along with a human sniffer to assess the odorousness of the smells associated with each chemical compound.
The researchers found that most of the chemicals responsible for body odor were similar between the two groups of volunteers. But there were a few that made the difference. Teenage sweat, for example, had high levels of many kinds of carboxylic acids, which the assessors described as "earthy, musty or cheesy."
They also found two steroids in the teen sweat not present in the baby sweat, one of which resulted in "musk or urine-like" emanations—the other, the assessors suggested, smelled more like "musk and sandalwood." Without such chemicals, the sweat of babies smelled much sweeter.
The researchers suggest that study of the chemical compounds in teen sweat could prove fruitful for makers of odor-control products. They also suggest that more work could done to better understand the impact of such odors on parents.

Diana Owsienko et al, Body odor samples from infants and post-pubertal children differ in their volatile profiles, Communications Chemistry (2024). DOI: 10.1038/s42004-024-01131-4

Messenger RNAs with multiple 'tails' could lead to more effective therapeutics: researchers

Messenger RNA (mRNA) made its big leap into the public limelight during the pandemic, thanks to its cornerstone role in several COVID-19 vaccines. But mRNAs, which are genetic sequences that instruct the body to produce proteins, are also being developed as a new class of drugs. For mRNAs to have broad therapeutic uses, however, the molecules will need to last longer in the body than those that make up the COVID vaccines.

Researchers have engineered a new mRNA structure by adding multiple "tails" to the molecules that boosted mRNA activity levels in cells by five to 20 times. They  also showed that their multi-tailed mRNAs lasted two- to three-times longer in animals compared to unmodified mRNA, and when incorporated into a CRISPR gene-editing system, resulted in more efficient gene editing in mice.

The new mRNAs, reported in Nature Biotechnology, could potentially be used to treat diseases that require long-lasting treatments that edit genes or replace faulty proteins.

Scientists have shown that non-natural structures can function so much better than naturally occurring ones. This research has given them a lot of confidence in their ability to modify mRNA molecules chemically and topologically.

Branched chemically modified poly(A) tails enhance the translation capacity of mRNA, Nature Biotechnology (2024). DOI: 10.1038/s41587-024-02174-7

Prosopometamorphopsia: a condition where people see  'demonic' face distortions

Imagine if every time you saw a face, it appeared distorted. Well, for those who have a very rare condition known as prosopometamorphopsia (PMO), which causes facial features to appear distorted, that is reality.

Prosopometamorphopsia explains, "Prosopo comes from the Greek word for face 'prosopon' while 'metamorphopsia' refers to perceptual distortions.  Specific symptoms vary from case to case and can affect the shape, size, color, and position of facial features. The duration of PMO also varies; it "can last for days, weeks, or even years.

A new Dartmouth study published in the "Clinical Pictures" section of The Lancet reports on a unique case of a patient with PMO. The research is the first to provide accurate and photorealistic visualizations of the facial distortions experienced by an individual with PMO.

The patient, a 58-year-old male with PMO, sees faces without any distortions when they are viewed on a screen and on paper, but he sees distorted faces that appear "demonic" when viewed in-person. Most PMO cases however, see distortions in all contexts, so his case is especially rare and presented a unique opportunity to accurately depict his distortions.

Scientists have heard from multiple people with PMO that they have been diagnosed by psychiatrists as having schizophrenia and put on anti-psychotics, when their condition is a problem with the visual system,  according to the researchers.

And it's not uncommon for people who have PMO to not tell others about their problem with face perception because they fear others will think the distortions are a sign of a psychiatric disorder.

"It's a problem that people often don't understand."

Through their paper, the researchers hope to increase public awareness of what PMO is.

Visualising facial distortions in prosopometamorphopsia, The Lancet (2024). www.thelancet.com/journals/lan … (24)00136-3/fulltext

Accumulation of 'junk proteins' identified as one cause of aging and possible source of ALS

Amyotrophic lateral sclerosis (ALS) is a degenerative disease. The neurons responsible for movement begin to die and muscle control is progressively lost, leading to a fatal outcome. The causes of ALS are currently unknown, and there is no effective treatment.

In a paper published in Molecular Cell, researchers provide the first evidence that a possible cause of the hereditary type of ALS—familial ALS—is the accumulation in motor neurons of "junk proteins," proteins with no function that wrongly accumulate and prevent the cell from functioning properly.

Specifically, these non-functional proteins that accumulate are ribosomal proteins, which normally form ribosomes, molecular factories in charge of protein production.

Most patients with hereditary ALS share mutations in a gene called C9ORF72. This mutation results in the production of toxic proteins—or peptides—rich in the amino acid arginine. In a previous work,  the same researchers took the first steps to understand why these peptides are toxic. The reason is that these toxins stick to DNA and RNA "as if they were tar," affecting virtually all reactions in the cell that use these nucleic acids.

Thus, this study provides a new hypothesis for understanding the origin of ALS, by suggesting that it has a similar origin to another group of rare diseases known as ribosomopathies, also associated with an excess of non-functional ribosomal proteins (in the case of ALS, this problem is restricted to motor neurons).

The new study also opens a new front in a different area, aging research. The authors propose a new causal factor in the aging process, which until now would have been overlooked: nucleolar stress, a mechanism by which organelles called nucleoli react to various damages in the cell.

In this new work, scientists report a new model that explains how nucleolar stress induces toxicity in animal cells, and they provide direct evidence that it accelerates aging in mammals. This is the first experimental evidence that generating nucleolar stress accelerates aging.

Nucleolar stress caused by arginine-rich peptides triggers a ribosomopathy and accelerates aging in mice, Molecular Cell (2024). DOI: 10.1016/j.molcel.2024.02.031. www.cell.com/molecular-cell/fu … 1097-2765(24)00173-4

The World's First 'Unconventional' Superconductor was Found in Nature

Few materials have the uncanny talent of carrying a current with virtually no resistance in what is known as superconductivity. The smallest handful of those can be found in nature. Scientists have discovered that one material with a formula found in nature is capable of superconducting at low temperatures without using the typical quantum trickery, making it the first unconventional superconductor of its kind. Superconductors are fascinating and also hugely useful, because they conduct electricity without energy loss. This is typically thanks to their electrons sharing identity in what are known as Cooper pairs, allowing them to slip through a jumble of atoms with relative ease. Cooper pairs in unconventional superconductors link up in ways that weren't described in early models on superconductivity, ways that also mean they appear at higher temperatures. Through a series of detailed lab tests, an international team of researchers found that the mineral miassite – already known to be a superconductor – can show the properties of an unconventional superconductor. That miassite occurs in nature as well as being something scientists can synthesize in the lab makes it even more unusual. However, it's worth pointing out that it's unlikely any pieces of miassite found in nature would ever have the purity required to function as an unconventional superconductor. you think that this is something which is produced deliberately during a focused search, and it cannot possibly exist in nature. But it turns out it does. Three different tests were used to establish the unconventional superconductivity of miassite, including the London penetration depth test, which measures the reaction of the material to a weak magnetic field. Another test involved creating defects in the material, which can affect the temperature at which it becomes a superconductor. Unconventional superconductors are much more sensitive to the disorder caused by these defects than conventional superconducting materials. The discovery was made as part of efforts to find new, novel materials to advance fields such as quantum science.

https://www.nature.com/articles/s43246-024-00456-w

New research shows unintended harms of organic farming

Although organic agricultural practices generally improve environmental conditions such as soil and water quality, the trade-offs aren't very well understood.

Organic farming is often touted as a more sustainable solution for food production, leveraging natural forms of pest control to promote eco-friendly cultivation.

But a new study published in Science on Thursday finds that expanding organic cropland can lead to increased pesticide use in surrounding non-organic fields, offsetting some environmental benefits.

These harmful "spillover effects" can be mitigated if organic farms are clustered together and geographically separated from conventional farms, the researchers found.

Organic fields could harbour more beneficial species that prey on insects, such birds, spiders and predatory beetles and fewer pests. Or, the lack of chemical pesticides and genetically modified seeds could mean they harbour more pests.

The researchers found that surrounding organic agriculture leads to an increase in pesticide use on conventional fields, but also leads to a larger decrease on nearby organic fields, with the effect manifesting primarily in insecticides, which specifically target insects. The level of pesticides in conventional fields decreased the further away they were from organic fields.

But the situation could be completely remedied if organic fields were grouped together, the researchers found. Spatially clustering organic fields and spatially separating organic and conventional fields could reduce the environmental footprint of both organic and conventional cropland, the team concluded.

 Farmers' decisions about pesticide are influenced by the presence of nearby organic fields—but it's not fully clear why.

The value of the crops, their susceptibility to pests, and farmers' personal risk tolerances likely all play roles.

Which mobile pests are involved, where they originate in the landscape, or how and why they move across the landscape are poorly understood, according to the researchers  calling for more research in this area.

Ashley E. Larsen et al, Spillover effects of organic agriculture on pesticide use on nearby fields, Science (2024). DOI: 10.1126/science.adf2572

Erik Lichtenberg, Collateral impacts of organic farming, Science (2024). DOI: 10.1126/science.ado4083

Cool paint coatings help pedestrians feel up to 1.5 degrees Celsius cooler in urban setting, a field study finds

A real-world study by researchers  has shown that the use of cool paint coatings in cities can help pedestrians feel up to 1.5 degrees Celsius cooler, making the urban area more comfortable for work and play.

Cool paint coatings contain additives that reflect the sun’s heat to reduce surface heat absorption and emission. They have been touted as one way to cool down the urban area and mitigate the Urban Heat Island (UHI) effect, a phenomenon in which urban areas experience warmer temperatures than their outlying surroundings.

Researchers have conducted a first of its kind real-world study in the tropics to comprehensively evaluate how well cool paint coatings work in reducing city heat.

The team coated the roofs, walls, and road pavements of an industrial area in Singapore and found that by comparison with an adjacent uncoated area, the coated environment was up to two degrees Celsius cooler in the afternoon, with pedestrian thermal comfort level improving by up to 1.5 degrees Celsius, measured using the Universal Thermal Climate Index - a common international standard for human outdoor temperature sensation that takes into account temperature, relative humidity, thermal radiation, and wind speed.

This  study provides evidence that cool paint coatings reduce heat build-up and contribute to the cooling of the urban environment. This is a minimally intrusive solution for urban cooling that has an immediate effect, compared to other options that often require major urban redevelopment to deploy. Moreover, by reducing the amount of heat absorbed in urban structures, we also reduce heat load in buildings, consequently reducing indoor air-conditioning energy consumption.

E. V. S. Kiran Kumar Donthu, Yong Ping Long, Man Pun Wan, Mandi Zhou, Bing Feng Ng. Dynamics of cool surface performance on urban microclimate: A full-scale experimental study in Singapore. Sustainable Cities and Society, 2024; 102: 105218 DOI: 10.1016/j.scs.2024.105218

Scientists develop ultra-thin semiconductor fibers that turn fabrics into wearable electronics

Scientists  have developed ultra-thin semiconductor fibers that can be woven into fabrics, turning them into smart wearable electronics. Their work has been published in the journal Nature.

To create reliably functioning semiconductor fibers, they must be flexible and without defects for stable signal transmission. However, existing manufacturing methods cause stress and instability, leading to cracks and deformities in the semiconductor cores, negatively impacting their performance and limiting their development.

Scientists conducted modeling and simulations to understand how stress and instability occur during the manufacturing process. They found that the challenge could be overcome through careful material selection and a specific series of steps taken during fiber production.

They developed a mechanical design and successfully fabricated hair-thin, defect-free fibers spanning 100 meters, which indicates its market scalability. Importantly the new fibers can be woven into fabrics using existing methods.

To demonstrate their fibers' high quality and functionality, the  research team developed prototypes. These included a smart beanie hat to help a visually impaired person cross the road safely by receiving alerts on a mobile phone application; a shirt that receives information and transmits it through an earpiece, like a museum audio guide; and a smartwatch with a strap that functions as a flexible sensor that conforms to the wrist of users for heart rate measurement even during physical activities.

The researchers think that their innovation is a fundamental breakthrough in the development of semiconductor fibers that are ultra-long and durable, meaning they are cost-effective and scalable while offering excellent electrical and optoelectronic (meaning it can sense, transmit and interact with light) performance.

Zhixun Wang et al, High-quality semiconductor fibres via mechanical design, Nature (2024). DOI: 10.1038/s41586-023-06946-0

Space research in anti-cancer fight

Experiments in the weightless environment of space have led to "crazy progress" in the fight against cancer, NASA officials say.

Not only do cells in space age more rapidly, speeding up research, their structures are also described as "purer."

They all don't clump together (as they do) on Earth because of gravity. They are suspended in space enabling better analysis of their molecular structures.

Research conducted in space can help make cancer drugs more effective.

Pharmaceutical giant Merck has conducted research on the ISS with Keytruda, an anti-cancer drug that patients now receive intravenously.

Its key ingredient is difficult to transform into a liquid. One solution is crystallization, a process often used in drug manufacturing.

In 2017, Merck conducted experiments to see if the crystals would form more rapidly in space than on Earth.

Two pictures taken  demonstrate the difference. The first showed a blurry, transparent spot. But on the second, a large number of clear gray spots had emerged.

That photo showed that smaller, more uniform crystals were forming in space—and "forming better".

Thanks to such research, researchers will be able to make a drug that can be administered by injection in a doctor's office instead of through long and painful chemotherapy treatments.

Part 1

Merck identified techniques that can help it imitate the effects of these crystals on Earth as it works to develop a drug that can be stored at room temperature.

Still, it can take years between research in space and the wide availability of a drug developed there.

Cancer research in space began more than 40 years ago but has become "revolutionary" in recent years.

Biden launched a "Cancer Moonshot" initiative in 2016, when he was then vice president, echoing a speech by John F. Kennedy some 60 years earlier outlining the bold goal of sending an American to the moon.

The goal of the "Moonshot" is to halve the death rate from cancer over the next quarter century, saving four million lives, according to the White House.

Political realities may hinder that ambitious goal, though. Congress has earmarked just over $25 billion to NASA for 2024, two percent less than the previous year and well below what the White House had sought.

"The ability of space to capture the imagination is huge. And space cancer research has a firm goal: "It can save lives." and should be pursued, according to the scientific community.

Source: AFP

Part 2

 Unintended consequences of fire suppression

The escalation of extreme wildfires globally has prompted a critical examination of wildfire management strategies. A new study reveals how fire suppression ensures that wildfires will burn under extreme conditions at high severity, exacerbating the impacts of climate change and fuel accumulation.

The study used computer simulations to show that attempting to suppress all wildfires results in fires burning with more severe ecological impacts, with accelerated increases in burned area beyond those expected from fuel accumulation or climate change.

Fire suppression has unintended consequences, say the researchers. We've known for a long time that suppressing fires leads to fuel accumulation. Here, the researchers show a separate counter-intuitive outcome.

Though fire suppression reduces the overall area burned, it mainly eliminates low- and moderate-intensity fires. As a result, the remaining fires are biased to be more extreme. The study, "Fire suppression makes wildfires more severe and accentuates impact...," published in Nature Communications, shows how this "suppression bias" causes average fire severity to increase substantially.

Part 1

Over a human lifespan, the modeled impacts of the suppression bias outweigh those from fuel accumulation or climate change alone. This suggests that suppression may exert a significant and underappreciated influence on patterns of fire globally.

Fire suppression exacerbated the trends already caused by climate change and fuel accumulation, the study found, causing areas burned to increase three to five times faster over time relative to a world with no suppression.

Suppression, through preferentially removing low- and moderate-severity fire, also raised average fire severity by an amount equivalent to a century of fuel accumulation or climate change.

"By attempting to suppress all fires, we are bringing a more severe future to the present", say the researchers.

However, the new findings also show that allowing more low- and moderate-intensity fire can reduce or reverse the impacts of the suppression bias. Suppression strategies that allow fire to burn under moderate weather conditions—while still suppressing fires during more dangerous fire weather—reduced average fire severity and moderated the rate of burned area increase, the team found.

Developing and implementing technologies and strategies to safely manage wildfires during moderate burning conditions is essential. This approach may be just as effective as other necessary interventions, like mitigating climate change and decreasing unintentional human-related ignitions.

 Kreider, M.R., et al. Fire suppression makes wildfires more severe and accentuates impacts of climate change and fuel accumulation. Nature Communications (2024). doi.org/10.1038/s41467-024-46702-0

Part 2

**

The world is one step closer to secure quantum communication on a global scale

Researchers have brought together two Nobel prize-winning research concepts to advance the field of quantum communication.

Scientists can now efficiently produce nearly perfect entangled photon pairs from quantum dot sources. The research, "Oscillating photonic Bell state from a semiconductor quantum dot for quantum key distribution," was published in Communications Physics.

Entangled photons are particles of light that remain connected, even across large distances, and the 2022 Nobel Prize in Physics recognized experiments on this topic. Combining entanglement with quantum dots, a technology recognized with the Nobel Prize in Chemistry in 2023, the IQC research team aimed to optimize the process for creating entangled photons, which have a wide variety of applications, including secure communications.

By embedding semiconductor quantum dots into a nanowire, the researchers created a source that creates near-perfect entangled photons 65 times more efficiently than previous work.

This new source can be excited with lasers to generate entangled pairs on command. The researchers then used high-resolution single photon detectors provided by Single Quantum in The Netherlands to boost the degree of entanglement.

Using their new quantum dot entanglement source, the researchers simulated a secure communications method known as quantum key distribution, proving that the quantum dot source holds significant promise in the future of secure quantum communications.

Matteo Pennacchietti et al, Oscillating photonic Bell state from a semiconductor quantum dot for quantum key distribution, Communications Physics (2024). DOI: 10.1038/s42005-024-01547-3

Astronauts have surprising ability to know how far they 'fly' in space

New research finds that astronauts have a surprising ability to orient themselves and gauge distance traveled while free from the pull of gravity.

The findings of the study, done in collaboration with the Canadian Space Agency and NASA, have implications for crew safety in space and could potentially give clues to how aging affects people's balance systems here on Earth.

It has been repeatedly shown that the perception of gravity influences perceptual skill. The most profound way of looking at the influence of gravity is to take it away, which is why the researchers took their research into space.

Based on these findings it seems as though humans are surprisingly able to compensate adequately for the lack of an Earth-normal environment using vision.

The researchers studied a dozen astronauts aboard the International Space Station, which orbits about 400 kilometers from the Earth's surface.

Here, Earth's gravity is approximately canceled out by centrifugal force generated by the orbiting of the station. In the resulting microgravity, the way people move is more like flying. People have previously anecdotally reported that they felt they were moving faster or further than they really were in space, so this provided some motivation actually to record this.

The researchers compared the performance of a dozen astronauts—six men and six women—before, during, and after their year-long missions to the space station and found that their sense of how far they traveled remained largely intact.

The study, published recently in npj Microgravity, has been a decade in the making and represents the first of three papers that will emerge from the research investigating the effects of microgravity exposure on different perceptual skills including the estimation of body tilt, traveled distance, and object size.

part1

This research shows exposure to microgravity mimics the aging process on a largely physiological level—wasting of bones and muscles, changes in hormonal functioning, and increased susceptibility to infection—but this paper finds that self-motion is mainly unaffected, suggesting the balance issues that frequently come from old age may not be related to the vestibular system.

It suggests that the mechanism for the perception of movement in older people should be relatively unaffected and that the issues involved in falling may not be so much in terms of the perception of how far they've moved, but perhaps more to do with how they're able to convert that into a balance reflex.

Björn Jörges et al, The effects of long-term exposure to microgravity and body orientation relative to gravity on perceived traveled distance, npj Microgravity (2024). DOI: 10.1038/s41526-024-00376-6

Part 2

Pregnancy advances ‘biological age’
Studies in mice and humans suggest that being pregnant can increase a person’s ‘biological age’ by a couple of years — but giving birth reverses these changes. Biological age can be estimated from patterns of DNA methylation, which occurs when chemical methyl groups are added to DNA. The patterns reflect the stresses that a body accrues over time. The work supports the idea that “biological age is quite flexible; it’s a fluid parameter. It can go up and down”, says biomedical scientist Vadim Gladyshev.

https://www.nature.com/articles/d41586-024-00843-w?utm_source=Live+...

https://www.sciencedirect.com/science/article/abs/pii/S155041312400...

Pregnancy advances a woman's ‘biological’ age — but giving birth turns it back

The chemical tags analysed in the study are called methyl groups, and they are added to DNA in a process called methylation. They are one example of the ‘epigenome’, features of DNA that change gene activity without altering the genetic code.
DNA-methylation patterns can be used to estimate a person’s ‘biological age’, which reflects the physiological stresses that a person’s body has accrued over time. Some research has found that biological age is a better predictor of health problems such as cardiovascular disease3 and dementia4 than a person’s chronological age.
But unlike chronological age, “biological age is quite flexible; it’s a fluid parameter. It can go up and down”.

Physicists Capture Elusive 4D 'Ghost' in CERN Particle Accelerator

There's a specter haunting the tunnels of a particle accelerator at CERN.

In the Super Proton Synchrotron, physicists have finally measured and quantified an invisible structure that can divert the course of the particles therein, and create problems for particle research.

It's described as taking place in phase space, which can represent one or more states of a moving system. Since four states are required to represent the structure, the researchers view it as four-dimensional.

This structure is the result of a phenomenon known as resonance, and being able to quantify and measure it takes us a step closer to solving a problem universal to magnetic particle accelerators.

"With these resonances, what happens is that particles don't follow exactly the path we want and then fly away and get lost," says physicist Giuliano Franchetti of GSI in Germany. "This causes beam degradation and makes it difficult to reach the required beam parameters."

Part 1

Resonance occurs when two systems interact and sync up. It could be a resonance emerging between planetary orbits as they gravitationally interact in their journey around a star, or a tuning fork that starts to sympathetically ring when sound waves from another tuning fork hit its tines.

Particle accelerators use powerful magnets that generate electromagnetic fields to guide and accelerate beams of particles to where physicists want them to go. Resonances can occur in the accelerator due to imperfections in the magnets, creating a magnetic structure that interacts with particles in problematic ways.

The more degrees of freedom a dynamic system exhibits, the more complex it is to describe mathematically. Particles moving through a particle accelerator are usually described using just two degrees of freedom, reflecting the two coordinates needed to define a point on a flat grid.

To describe structures therein requires mapping them using additional features in phase space beyond just the up-down, left-right dimensions; that is, four parameters are needed to map each point in the space.

This, the researchers say, is something that could very easily "elude our geometric intuition".

Part 2

"In accelerator physics, the thinking is often in only one plane," Franchetti says. In order to map a resonance, however, the particle beam needs to be measured across both the horizontal and the vertical planes.

It sounds pretty straightforward, but if you're used to thinking about something a specific way, it might take an effort to think outside the box. Understanding the effects of resonance on a particle beam took quite a few years, and some hefty computer simulations.

However, that information opened the way for Franchetti, along with physicists Hannes Bartosik and Frank Schmidt of CERN, to finally measure the magnetic anomaly.

Using beam position monitors along the Super Proton Synchrotron, they measured the position of the particles for approximately 3,000 beams. By carefully measuring where the particles were centered, or skewed to one side, they were able to generate a map of the resonance haunting the accelerator.

Part 3

"What makes our recent finding so special is that it shows how individual particles behave in a coupled resonance," Bartosik says. "We can demonstrate that the experimental findings agree with what had been predicted based on theory and simulation."

The next step is to develop a theory that describes how individual particles behave in the presence of an accelerator resonance. This, the researchers say, will ultimately give them a new way to mitigate beam degradation, and achieve the high-fidelity beams required for ongoing and future particle acceleration experiments.

The team's research has been published in Nature Physics.

https://www.nature.com/articles/s41567-023-02338-3

Part 4

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Scientists Ignited a Thermonuclear Explosion Inside a Supercomputer

Computer simulations are giving us new insight into the riotous behavior of cannibal neutron stars.

When a neutron star slurps up material from a close binary companion, the unstable thermonuclear burning of that accumulated material can produce a wild explosion that sends X-radiation bursting across the Universe.

How exactly these powerful eruptions evolve and spread across the surface of a neutron star is something of a mystery. But by trying to replicate the observed X-ray flares using simulations, scientists are learning more about their ins and outs – as well as the ultra-dense neutron stars that produce them.

Part 1

Neutron stars are some of the densest objects in the Universe. They're what's left over after a massive star has lived its life, run out of fuel, and exploded in a supernova.

While the outer material blasts off into space, though, the core of the star collapses under gravity, forming a super dense ball around 20 kilometers (12 miles) across, packing as much mass into that tiny sphere as up to 2.3 Suns or so.

Matter that is squished so densely is expected to be a bit wacky, to put it mildly. But scientists can study their thermonuclear bursts to place constraints on their size, which in turn can help model their interiors.

We can't exactly go cozy up to a neutron star to look at them more closely, for a number of reasons (distance, danger, that sort of thing), but we can collect all the information we can about neutron star X-ray bursts, and try to put together a simulation whose results match the observational data.

Part 2

That sounds simple, but the physics of neutron stars is really complicated; simulating their behavior requires a lot of computing power.

In previous work, the researchers used the Summit supercomputer at Oak Ridge National Laboratory to simulate the thermonuclear flames in two dimensions. Now they've built on that work, and scaled their simulations up to a third dimension.

The model 3D neutron star had a temperature several million times hotter than the Sun, and a spin speed of 1,000 rotations per second, which is pretty close to the theoretical upper limit of neutron star spin speed. Then, they simulated the early evolution of the thermonuclear flame.

Although the flame in the 2D simulation spread slightly faster than the 3D version, the growth trends in both models were very similar. This agreement means that the 2D simulation remains a good tool for studying these hectic explosions, but there are still some things it can't do.

For example, turbulence behaves differently in two and three dimensions; but being able to use the 2D sim for the parts it can do will free up computing power for other things, like increasing the fidelity of the burning

Part 3

With this information to hand, the simulations can be put to work to provide real insights into how neutron stars throw their tremendous tantrums.

"We're close to modeling the flame spread across the whole star from pole to pole.

https://iopscience.iop.org/article/10.3847/1538-4357/ace04e

Part 4

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Scientists Warn The Price of Food Is Expected to Increase Every Year From Now on
Climate change, and specifically rising temperatures, may cause food prices to increase by 3.2% per year, according to a new study by researchers in Germany.

As climate change continues to worsen, this price inflation will mean more and more people around the world don't have a varied and healthy diet, or simply don't have enough food.

The new analysis shows that global warming could cause food price inflation to increase by between 0.9 and 3.2 percentage points per year by 2035. The same warming will cause a smaller rise in overall inflation (between 0.3 and 1.2 percentage points), so a greater proportion of household income would need to be spent on buying food.

This effect will be felt worldwide, by high and low-income countries alike, but nowhere more so than in the global south. As with various other consequences of climate change, Africa will be worst affected despite contributing little to its causes.

Shifting seasons, pests and diseases
The first is that the same climate change effects that are causing the inflation are already making food harder to get hold of. For instance, higher temperatures can cause long-established and predictable farming seasons to shift and so may hinder crop production.

Other consequences can include more pest and disease outbreaks that deplete livestock and food reserves, and heat stress to already-poor roads which makes it harder to access rural communities.
Part 1

https://files.springernature.com/getResource/Full%20text%20article....

All of these factors push prices higher and reduce the purchasing power of affected households. The drivers of food inflation are already worsening food insecurity.

The second part of this problem is the rise in inflation itself. A 3% annual price increase would mean households are less able to purchase what they need.

They would likely need to compromise on quality or perhaps even culturally important foods. This in turn makes people more vulnerable to disease and other health issues. Malnutrition is the leading cause of immunodeficiency globally.

Alterations in the climate are a hunger-risk multiplier for those populations with entrenched vulnerability. In light of this, 134 countries at COP28 signed a declaration to incorporate food systems into their climate action, to ensure everyone has enough to eat in light of climate change.

The researchers behind the new study suggest that reducing greenhouse gas emissions could limit any impacts on the global economy. We also suggest that diversifying economies would serve as some protection for those communities reliant on agriculture for both their food and income.

Government intervention could also ensure financial protection and nutritional aid for those vulnerable to becoming trapped in the poverty cycle by inflation and diminished accessibility to food.

https://theconversation.com/food-prices-will-climb-everywhere-as-te...

Part 2

Tiniest 'starquakes' detected

At a distance of 11.9 light years, Epsilon Indi (ε Indi) is an orange dwarf star (also known as a K dwarf) with 71% of the sun's diameter. An international team, led by Instituto de Astrofísica e Ciências do Espaço (IA) researcher Tiago Campante, studied this star with the ESPRESSO spectrograph, mounted at the European Southern Observatory's (ESO) Very Large Telescope (VLT), and detected the tiniest "starquakes" ever recorded.

The team used a technique dubbed asteroseismology, which measures oscillations in stars. These provide indirect glimpses of stellar interiors, just as earthquakes tell us about Earth's interior. In ε Indi, the peak amplitude of the detected oscillations is just 2.6 centimeters per second (about 14% of the sun's oscillation amplitude), which makes it the smallest and coolest dwarf star observed to date with confirmed solar-like oscillations.

These measurements are so precise that the detected speed is slower than the average speed of a sloth.

The extreme precision level of these observations is an outstanding technological achievement. Importantly, this detection conclusively shows that precise asteroseismology is possible down to cool dwarfs with surface temperatures as low as 4,200 degrees Celsius, about 1,000 degrees cooler than the sun's surface, effectively opening up a new domain in observational astrophysics.

This level of precision might help scientists settle a long-standing disagreement between theory and observations in what concerns the relation between the mass and the diameter of these cool-dwarf stars.

These "starquakes" can now be used to help plan the future European Space Agency's (ESA) PLATO space telescope, a mission in which IA is strongly involved. The oscillation amplitudes measured in this study can be converted to amplitudes in photometry, as they will be measured by PLATO, this being a key piece of information to help accurately predict the seismic yield of PLATO, scheduled to be launched in 2026.

Campante et al, Expanding the frontiers of cool-dwarf asteroseismology with ESPRESSO. Detection of solar-like oscillations in the K5 dwarf ϵ Indi, Astronomy & Astrophysics (2024). DOI: 10.1051/0004-6361/202449197

Albedo can reduce climate benefit of tree planting: New tool identifies locations with high climate-cooling potential

As efforts to restore tree cover accelerate to help avoid runaway climate change, a new study highlights how restoring tree cover can, in some locations, heat up the Earth rather than cool it by affecting how much sunlight the surface reflects (i.e. "the albedo").

This new study by researchers published recently in the journal Nature Communications, provides a global analysis of where restoration of tree cover is most effective at cooling the global climate system, considering not just the cooling from carbon storage but also the warming from decreased albedo.

The researchers provide a tool practitioners and land managers can use to determine just how much of a problem albedo is for any reforestation or afforestation project on the globe. The authors use these new maps to show that previously published 'carbon-only' estimates of the global climate mitigation potential of restoring trees worldwide provided significant overestimation, being anywhere from 20 to 81% too high. Because comprehensive maps of the consequences of albedo change were not previously available, these carbon-only estimates tend to identify too many options in landscapes—particularly semi-arid settings and snowy, boreal regions—where changes in albedo would significantly offset, or even negate, the carbon-removing benefits provided by these trees.

Part 1

The balance of carbon storage versus albedo change that comes from restoring tree cover varies from place to place, but until now we didn't have the tools to tell the good climate solutions from the bad.

This study aims to change that, providing the maps needed to empower smarter decisions while also ensuring that limited finance is directed at those locations where restoring tree cover can make the most positive difference as a natural climate solution.

On the positive, the study also identifies locations within every biome on Earth where the climate mitigation benefits of tree-planting can be achieved. Better still, it also finds that most of the thousands of on-the-ground projects underway globally to restore tree cover are concentrated in these zones of greatest opportunity. Even in these locations, however, albedo changes are likely to offset the net climate benefit by at least 20 percent in around two-thirds of cases.

Researchers have now addressed a significant research gap and gained a much more complete picture of how restoring tree cover can impact our global climate—both positively and also sometimes negatively.

However, it's important to remember that there are many other sound reasons to restore tree cover, even in locations where the climate benefits aren't stellar: clean water, resilient food production, wildlife habitat, the list goes on... Researchers are 're simply calling on governments and land managers to more carefully integrate albedo in their environmental decision-making and are open-sourcing this robust new set of tools to help them do so.

Hasler N., Accounting for albedo change to identify climate positive tree cover restoration., Nature Communications (2024). DOI: 10.1038/s41467-024-46577-1 , www.nature.com/articles/s41467-024-46577-1

To read more about efforts to restore tree cover and to chart the full potential of nature to mitigate climate change, visit naturebase.org to learn more.

Part 2

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Dust storms may spread bacteria and fungi around the world

When allergy season hits, many blame their reactions on the local flora in the spring. However, African Saharan-Sahelian dust plumes, large enough to register on weather radar, travel around the globe every summer, bringing their own form of air pollution.

Researchers  have furthered previous research to identify microorganisms that might have hitched a ride in the du.... 

We all get allergies and potentially other more severe health effects when we breathe in dust, and it's not fully known as to what causes those allergies. Some people may think it is just the sand or clay minerals in the dust. Others think it is the metals or organics in the dust, and then some think it's the bacteria and fungi.

This research, published in the journal Environmental Science & Technology, is the first to study the association of bacteria and fungi with North American–Saharan dust storms.

Scientists noted that dust events can vary annually, with different elemental compositions each year.

 Microbiota was detected by extracting DNA from filters. Meticulous sequencing techniques detected bacterial genomes from 117 families and fungal genomes from 164 families. The technique did not show whether the microbes were alive, but it did detect several pathogenic bacteria and fungi, many of which are listed in the World Health Organization's global priority list of human pathogens.

It doesn't tell us if they are going to be able to infect us and make us sick. But at least the DNA of several pathogenic bacteria and fungi were identified in the African dust.

The biodiversity of bacteria and fungi was strongly correlated to a few elements, most notably calcium. The study showed that calcium and zirconium are important for explaining bacterial and fungal beta diversity, the ratio between regional and local species diversity.

A similar caveat was found in biota detections. Over 2,000 different organic groups were detected. 

Sourav Das et al, Respirable Metals, Bacteria, and Fungi during a Saharan–Sahelian Dust Event in Houston, Texas, Environmental Science & Technology (2023). DOI: 10.1021/acs.est.3c04158

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If you've got a dark roof, you're spending almost $700 extra a year to keep your house cool

A dark roof means you'll pay considerably more to keep your house cool in summer.When suburbs are full of dark colored roofs, the whole area heats up. And up. And up. This is part of the urban heat island effect.

Light coloured roofs or Cool roofs have many benefits. They slash how much heat gets into your house from the sun, keep the air surrounding your home cooler, boost your aircon efficiency, and make your solar panels work more efficiently.

At present, the world's cities account for 75% of all energy-related carbon dioxide emissions. It's vitally important we understand what makes cities hotter or cooler.

Brick, concrete, tarmac and tiles can store more heat than grass and tree-covered earth can, and release it slowly over time. This keeps the air warmer, even overnight.

Built-up areas also block wind, which cuts cooling. Then there's transport, manufacturing and air-conditioning, all of which increase heat.

The main way people had to keep cool was through how they designed their homes. In hot countries, buildings are often painted white, as well as having small windows and thick stone walls.

Part 1

How can we cool our cities

Weird electron behaviour thrills physicists

Two teams have observed that electrons, which usually have a charge of –1, can behave as if they had fractional charges (such as –⅔) — and do so without being nudged by an external magnetic field. It’s the first time this ‘fractional quantum anomalous Hall effect’ has been observed experimentally, and physicists are scratching their heads over exactly how it works. It’s a fundamental discovery that might also someday have practical applications: fractionally charged particles are a key requirement for a certain type of quantum computer. 

symbolic gesture in birds

Japanese tits (Parus minor) flutter their wings to invite their mate to enter the nest first. Scientists who observed eight breeding pairs of wild tits noticed that when one of the birds sat in front of the next box and fluttered its wings, the other would go in first. It’s the first documented evidence of birds using a symbolic gesture: one that has a specific meaning (like waving ‘goodbye’) but isn’t simply pointing at an object of interest. “It implies that birds have a level of understanding of symbolism that probably a lot of people wouldn’t have given them credit for before.

Astronomers unveil strong magnetic fields spiraling at the edge of Milky Way's central black hole

A new image from the Event Horizon Telescope (EHT) collaboration—which includes scientists from the Center for Astrophysics | Harvard & Smithsonian (CfA)— has uncovered strong and organized magnetic fields spiraling from the edge of the supermassive black hole Sagittarius A* (Sgr A*).

Seen in polarized light for the first time, this new view of the monster lurking at the heart of the Milky Way galaxy has revealed a magnetic field structure strikingly similar to that of the black hole at the center of the M87 galaxy, suggesting that strong magnetic fields may be common to all black holes. This similarity also hints toward a hidden jet in Sgr A*.

The results were published in The Astrophysical Journal Letters.

Scientists unveiled the first image of Sgr A*—which is approximately 27,000 light-years away from Earth—in 2022, revealing that while the Milky Way's supermassive black hole is more than a thousand times smaller and less massive than M87's, it looks remarkably similar.

So scientists decided to check whether they are similar in all the  ways possible.

Part 1

Light is an oscillating or moving, electromagnetic wave that allows us to see objects. Sometimes, light oscillates in a preferred orientation, and we call it "polarized." Although polarized light surrounds us, to human eyes it is indistinguishable from "normal" light.

In the plasma around these black holes, particles whirling around magnetic field lines impart a polarization pattern perpendicular to the field. This allows astronomers to see in increasingly vivid detail what's happening in black hole regions and map their magnetic field lines.

By imaging polarized light from hot glowing gas near black holes, researchers are directly inferring the structure and strength of the magnetic fields that thread the flow of gas and matter that the black hole feeds on and ejects. Polarized light teaches us a lot more about the astrophysics, the properties of the gas, and mechanisms that take place as a black hole feeds.

Scientists are excited to have images of both supermassive black holes in polarized light because these images and the data that come with them provide new ways to compare and contrast black holes of different sizes and masses. As technology improves, the images are likely to reveal even more secrets of black holes and their similarities or differences.

 "M87* and Sgr A* are different in a few important ways: M87* is much bigger, and it's pulling in matter from its surroundings at a much faster rate. So, we might have expected that the magnetic fields also look very different. But in this case, they turned out to be quite similar, which may mean that this structure is common to all black holes.

A better understanding of the magnetic fields near black holes helps us answer several open questions—from how jets are formed and launched to what powers the bright flares we see in infrared and X-ray light. 

Issaoun, S. et al, First Sagittarius A* Event Horizon Telescope Results. VII. Polarization of the Ring, The Astrophysical Journal Letters (2024), DOI: 10.3847/2041-8213/ad2df0

Ricarte A. et al, "First Sagittarius A* Event Horizon Telescope Results. VIII. Physical Interpretation of the Polarized Ring," The Astrophysical Journal Letters (2024), DOI: 10.3847/2041-8213/ad2df1

Part 2

Making long-term memories requires DNA damage, researchers discover

Just as you can't make an omelet without breaking eggs, scientists at Albert Einstein College of Medicine have found that you can't make long-term memories without DNA damage and brain inflammation. Their surprising findings were published in the journal Nature in a paper titled "Formation of memory assemblies through the DNA sensing TLR9 pathway."

Inflammation of brain neurons is usually considered to be a bad thing, since it can lead to neurological problems such as Alzheimer's and Parkinson's disease. But these new findings suggest that inflammation in certain neurons in the brain's hippocampal region is essential for making long-lasting memories.

The hippocampus has long been known as the brain's memory center.  Researchers found that a stimulus sets off a cycle of DNA damage and repair within certain hippocampal neurons that leads to stable memory assemblies—clusters of brain cells that represent our past experiences.

The researchers discovered this memory-forming mechanism by giving mice brief, mild shocks sufficient to form a memory of the shock event (episodic memory). They then analyzed neurons in the hippocampal region and found that genes participating in an important inflammatory signaling pathway had been activated.

Researchers observed strong activation of genes involved in the Toll-Like Receptor 9 (TLR9) pathway. This inflammatory pathway is best known for triggering immune responses by detecting small fragments of pathogen DNA. So at first scientists assumed the TLR9 pathway was activated because the mice had an infection. But looking more closely, they found, to their surprise, that TLR9 was activated only in clusters of hippocampal cells that showed DNA damage.

Brain activity routinely induces small breaks in DNA that are repaired within minutes. But in this population of hippocampal neurons, the DNA damage appeared to be more substantial and sustained.

Part 1

Triggering inflammation to make memories

Further analysis showed that DNA fragments, along with other molecules resulting from the DNA damage, were released from the nucleus, after which the neurons' TLR9 inflammatory pathway was activated; this pathway in turn stimulated DNA repair complexes to form at an unusual location: the centrosomes.

These organelles are present in the cytoplasm of most animal cells and are essential for coordinating cell division. But in neurons—which don't divide—the stimulated centrosomes participated in cycles of DNA repair that appeared to organize individual neurons into memory assemblies.

Cell division and the immune response have been highly conserved in animal life over millions of years, enabling life to continue while providing protection from foreign pathogens.

It seems likely that over the course of evolution, hippocampal neurons have adopted this immune-based memory mechanism by combining the immune response's DNA-sensing TLR9 pathway with a DNA repair centrosome function to form memories without progressing to cell division.

Part 2

During the week required to complete the inflammatory process, the mouse memory-encoding neurons were found to have changed in various ways, including becoming more resistant to new or similar environmental stimuli.

This is noteworthy because we're constantly flooded by information, and the neurons that encode memories need to preserve the information they've already acquired and not be 'distracted' by new inputs.

Importantly, the researchers found that blocking the TLR9 inflammatory pathway in hippocampal neurons not only prevented mice from forming long-term memories but also caused profound genomic instability, i.e., a high frequency of DNA damage in these neurons.

Genomic instability is considered a hallmark of accelerated aging as well as cancer and psychiatric and neurodegenerative disorders such as Alzheimer's.

Drugs that inhibit the TLR9 pathway have been proposed for relieving the symptoms of long COVID. But caution needs to be shown because fully inhibiting the TLR9 pathway may pose significant health risks, say the researchers. 

 Jelena Radulovic, Formation of memory assemblies through the DNA-sensing TLR9 pathway, Nature (2024). DOI: 10.1038/s41586-024-07220-7. www.nature.com/articles/s41586-024-07220-7

Part 3

Scientists discover how caterpillars can stop their 'bleeding' in seconds

Fully grown tobacco hornworms, ready to pupate, are between 7.5cm and 10cm long. They only contain a minute amount of hemolymph, which typically clots within seconds

Blood is a remarkable material: it must remain fluid inside blood vessels, yet clot as quickly as possible outside them, to stop bleeding. The chemical cascade that makes this possible is well understood for vertebrate blood. But hemolymph, the equivalent of blood in insects, has a very different composition, being notably lacking in red blood cells, hemoglobin, and platelets, and having amoeba-like cells called hemocytes instead of white blood cells for immune defense.

Just like blood, hemolymph clots quickly outside the body. How it does so has long remained an enigma. Now, materials scientists have shown in Frontiers in Soft Matter how this feat is managed by caterpillars of the Carolina sphinx moth. This discovery has potential applications for human medicine, the authors said.

 These caterpillars, called tobacco hornworms, can seal the wounds within a minute. They do that in two steps: first, in a few seconds, their thin, water-like hemolymph becomes 'viscoelastic' or slimy, and the dripping hemolymph retracts back to the wound.

Next, hemocytes aggregate, starting from the wound surface and moving up to embrace the coating hemolymph film that eventually becomes a crust sealing the wound.

To seal a wound, caterpillars transform blood from a viscous to a viscoelastic fluid in a few seconds, Frontiers in Soft Matter (2024). DOI: 10.3389/frsfm.2024.1341129. www.frontiersin.org/articles/1 … fm.2024.1341129/full

Risk factors for faster aging in the brain revealed in new study

In a new study published in Nature Communications, researchers investigated the genetic and modifiable influences on fragile brain regions by looking at the brain scans of 40,000 UK Biobank participants aged over 45.

Previously, the researchers had identified a 'weak spot' in the brain, which is a specific network of higher-order regions that not only develop later during adolescence, but also show earlier degeneration in old age. They showed that this brain network is also particularly vulnerable to schizophrenia and Alzheimer's disease.

In their latest study, the researchers examined 161 risk factors for dementia, and ranked their impact on this vulnerable brain network, over and above the natural effects of age.

They classified these so-called 'modifiable' risk factors—as they can potentially be changed throughout life to reduce the risk of dementia—into 15 broad categories: blood pressure, cholesterol, diabetes, weight, alcohol consumption, smoking, depressive mood, inflammation, pollution, hearing, sleep, socialization, diet, physical activity, and education.

We know that a constellation of brain regions degenerates earlier in aging, and in this new study researchers  have shown that these specific parts of the brain are most vulnerable to diabetes, traffic-related air pollution—increasingly a major player in dementia—and alcohol, of all the common risk factors for dementia.

They have found that several variations in the genome influence this brain network, and they are implicated in cardiovascular deaths, schizophrenia, Alzheimer's and Parkinson's diseases, as well as with the two antigens of a little-known blood group, the elusive XG antigen system, which was an entirely new and unexpected finding.

Part 1

In fact, two of these seven genetic findings are located in this particular region containing the genes of the XG blood group, and that region is highly atypical because it is shared by both X and Y sex chromosomes. This is really quite intriguing as we do not know much about these parts of the genome; our work shows there is benefit in exploring further this genetic terra incognita.

It is with this kind of comprehensive, holistic approach—and once we had taken into account the effects of age and sex—that three emerged as the most harmful: diabetes, air pollution, and alcohol.

This research sheds light on some of the most critical risk factors for dementia, and provides novel information that can contribute to prevention and future strategies for targeted intervention.

The effects of genetic and modifiable risk factors on brain regions vulnerable to ageing and disease, Nature Communications (2024). DOI: 10.1038/s41467-024-46344-2

Part 2