Artificial intelligence tool detects sex-related differences in brain structure

Artificial intelligence (AI) computer programs that process MRI results show differences in how the brains of men and women are organized at a cellular level, a new study shows. These variations were spotted in white matter, tissue primarily located in the human brain's innermost layer, which fosters communication between regions.

The work appears in Scientific Reports.

Men and women are known to experience multiple sclerosis, autism spectrum disorder, migraines, and other brain issues at different rates and with varying symptoms. A detailed understanding of how biological sex impacts the brain is therefore viewed as a way to improve diagnostic tools and treatments. However, while brain size, shape, and weight have been explored, researchers have only a partial picture of the brain's layout at the cellular level.

The new study used an AI technique called machine learning to analyze thousands of MRI brain scans from 471 men and 560 women. Results revealed that the computer programs could accurately distinguish between biological male and female brains by spotting patterns in structure and complexity that were invisible to the human eye.

The findings were validated by three different AI models designed to identify biological sex using their relative strengths in either zeroing in on small portions of white matter or analyzing relationships across larger regions of the brain.

These findings provide a clearer picture of how a living, human brain is structured, which may in turn offer new insight into how many psychiatric and neurological disorders develop and why they can present differently in men and women.

For the research,  researchers started by feeding AI programs existing data examples of brain scans from healthy men and women and also telling the machine programs the biological sex of each brain scan. Since these models were designed to use complex statistical and mathematical methods to get "smarter" over time as they accumulated more data, they eventually "learned" to distinguish biological sex on their own. Importantly, the programs were restricted from using overall brain size and shape to make their determinations.

According to the results, all of the models correctly identified the sex of subject scans between 92% and 98% of the time. Several features in particular helped the machines make their determinations, including how easily and in what direction water could move through brain tissue.

These results highlight the importance of diversity when studying diseases that arise in the human brain.

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If, as has been historically the case, men are used as a standard model for various disorders, researchers may miss out on critical insight.

While the AI tools could report differences in brain-cell organization, they could not reveal which sex was more likely to have which features.

According to the researchers, the team next plans to explore the development of sex-related brain structure differences over time to better understand environmental, hormonal, and social factors that could play a role in these  changes.

Deep Learning with Diffusion MRI as in vivo Microscope Reveals Sex-related Differences in Human White Matter Microstructure, Scientific Reports (2024).

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Analysis suggests people with more copies of ribosomal DNA have higher risks of developing disease

Ribosomal DNA (rDNA) is present in hundreds of copies in the genome, but has not previously been part of genetic analyses. A new study of 500,000 individuals indicates that people who have more copies of rDNA are more likely to develop inflammation and diseases during their lifetimes.

Standard genetic analysis techniques have not studied areas of the human genome that are repetitive, such as ribosomal DNA (rDNA), a fundamental part of the molecular mechanism which makes proteins in cells.

A new study has discovered that genetic disposition to disease can be found in these previously understudied areas of the genome.

The results, published in Cell Genomics, suggest that wider genome analysis could bring opportunities for preventative diagnostics, novel therapeutics, and greater insight into the mechanism of different human diseases.

In this study, samples from 500,000 individuals in the UK Biobank project were analyzed. Researchers used new whole genome sequencing (WGS) techniques to identify differences in numbers of copies of rDNA in each sample, and compared them with other health metrics and medical records.
The researchers found that the number of copies of rDNA in an individual showed strong statistical association with well-established markers of systemic inflammation—such as neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and systemic immune-inflammation index (SII). These statistically significant associations were seen in the genomes of individuals of different ethnicities, suggesting a common indicator for risks of future disease.

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rDNA copy number was also linked with an individual's kidney function within the sample of individuals of European ancestry. A similar effect was seen in samples from other ancestries, but further research using larger sample sizes will be needed to confirm this connection.

 This research highlights the importance of analyzing the whole genome to better understand the factors impacting on our health. This study is also an example of how having access to large biobanks allows us to make unexpected discoveries, and provides new avenues for harnessing the power of genetics to understand human diseases.

Geneticists have long struggled to fully explain the genetic basis of many common complex traits and diseases. This  work suggests that at least part of this missing heritability resides in difficult to sequence regions of the genome such as those encoding ribosomal copy number variation.

Ribosomal DNA Copy Number Variation Associates with Hematological Profiles and Renal Function in the UK Biobank, Cell Genomics (2024). DOI: 10.1016/j.xgen.2024.100562. www.cell.com/cell-genomics/ful … 2666-979X(24)00128-9

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Scientists develop sticky pesticide to combat pest insects

Researchers  have engineered a biological barrier that protects plants from diseases and pests. It concerns a sticky substance that is sprayed on leaves, to which pests stick.

The researchers hope that this insect glue will help to reduce the use of toxic chemical pesticides. They published their findings in the Proceedings of the National Academy of Sciences.

In the search for alternatives, scientists  turned to nature for inspiration. The carnivorous sundew plant has so-called glandular hairs that secrete a sticky substance to catch insects. The researchers wanted to mimic this to protect the plants and crops in a natural way.

The researchers succeeded in their endeavor.

They transformed vegetable rice oil into a yellow, sticky substance by blowing air over it and grinding it into small particles using a laboratory blender. This results in beads of about one millimeter in diameter that are as sticky as duct tape. The size matches one of the common pest insect: thrips. By catching these insects, plants stay healthier and are less likely to become infected with fungi that the thrips carry with them.

So far, the researchers mainly focused on this type of pest, but the insect glue may also work against other pests, such as the Suzuki fruit fly that currently threatens cherry cultivation. At the same time, the drops are small enough that beneficial insects, such as pollinators, do not get stuck.

Unlike chemical pesticides, insects are unlikely to develop resistance against this adhesive, the researchers think. 

Insects have already evolved so that they avoid adhesion, for example through hairs on their body and a bumpy surface. Increasing their body size remains one of the few escape methods from this sticky trap. That is not nearly as easy as developing tolerance to a chemical substance. If it happens at all, it takes many generations and only happens if the insect glue is used on a large scale.

After application, the sticky substance remains on the leaves for three months and cannot be washed off by rain. That is long enough to control pests until harvest. By spraying the insect glue on crops before the fruits develop, farmers minimize the chance of the pesticide getting onto the food. However, contact with food cannot be ruled out.

The advantage of this pesticide over chemical pesticides is that you can see the small, yellow drops. You can wash it off with water and dish soap. If you do ingest some of it, it is probably not harmful. As it is derived from vegetable oil.

 But scientists still need to investigate how (un)healthy it is exactly.

Ralph van Zwieten et al, Mimicking natural deterrent strategies in plants using adhesive spheres, Proceedings of the National Academy of Sciences (2024). DOI: 10.1073/pnas.2321565121

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Scientists discover blood proteins that may give cancer warning seven years before diagnosis

Two studies  have discovered proteins in the blood that could warn people of cancer more than seven years before it is diagnosed.

Scientists identified 618 proteins linked to 19 different types of cancer, including 107 proteins in a group of people who blood was collected at least seven years before diagnosis. The team has discovered that these proteins could be involved at the very earliest stages of cancer, where it could be prevented.

They think that some of these proteins could be used to detect cancer much earlier than is currently possible. In the future, this could help treat the disease at a much earlier stage or prevent it altogether.

The papers, titled "Identifying proteomic risk factors for cancer using prospective and exome analyses of 1,463 circulating proteins and risk of 19 cancers in the UK Biobank" and "Identifying therapeutic targets for cancer among 2,074 circulating proteins and risk of nine cancers," are published in Nature Communications.

In these studies, the team used a powerful technique called proteomics. Proteomics allows scientists to analyze a large set of proteins in tissue samples at a single point in time, to see how they interact with each other and find any important differences in proteins between different tissue samples.

In the first study, scientists analyzed blood samples from UK Biobank that had been taken from more than 44,000 people, including over 4,900 people who subsequently had a cancer diagnosis.

Using proteomics, the team analyzed a set of 1,463 proteins from a single sample of blood from each person. They compared the proteins of people who did and did not go on to be diagnosed with cancer to look for important differences between them and find out which ones were linked to cancer risk. The scientists also identified 182 proteins that differed in the blood three years before a cancer diagnosis took place.

In the second study, the scientists looked at genetic data from over 300,000 cancer cases to do a deep dive into which blood proteins were involved in cancer development and could be targeted by new treatments.

The scientists found 40 proteins in the blood that influenced someone's risk of getting 9 different types of cancer. While altering these proteins may increase or decrease the chances of someone developing cancer, the scientists also found that in some cases this may lead to unintended side effects.

However, the team stressed that they will need to do further research to find out the exact role these proteins play in cancer development, which of the proteins are the most reliable ones to test for, which tests could be developed to detect the proteins in the clinic, and which drugs could target these proteins.

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Identifying proteomic risk factors for cancer using prospective and exome analyses of 1,463 circulating proteins and risk of 19 cancers in the UK Biobank, Nature Communications (2024). www.nature.com/articles/s41467-024-48017-6

Karl Smith-Byrne et al, Identifying therapeutic targets for cancer among 2074 circulating proteins and risk of nine cancers, Nature Communications (2024). DOI: 10.1038/s41467-024-46834-3

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Scientists generate heat over 1,000°C with solar power instead of fossil fuel

Instead of burning fossil fuels to smelt steel and cook cement, researchers in Switzerland want to use heat from the sun. The proof-of-concept study, published May 15 in the journal Device, uses synthetic quartz to trap solar energy at temperatures over 1,000°C (1,832°F), demonstrating the method's potential role in providing clean energy for carbon-intensive industries.

Glass, steel, cement, and ceramics are at the very heart of modern civilization, essential for building everything from car engines to skyscrapers. However, manufacturing these materials demands temperatures over 1,000°C and relies heavily on burning fossil fuels for heat. These industries account for about 25% of global energy consumption.

Researchers have explored a clean-energy alternative using solar receivers, which concentrate and build heat with thousands of sun-tracking mirrors. However, this technology has difficulties transferring solar energy efficiently above 1,000°C.

To boost the efficiency of solar receivers, the researchers  turned to semitransparent materials such as quartz, which can trap sunlight—a phenomenon called the thermal-trap effect. The team crafted a thermal-trapping device by attaching a synthetic quartz rod to an opaque silicon disk as an energy absorber.

When they exposed the device to an energy flux equivalent to the light coming from 136 suns, the absorber plate reached 1,050°C (1,922°F), whereas the other end of the quartz rod remained at 600°C (1,112°F).

Using a heat transfer model, the team also simulated the quartz's thermal-trapping efficiency under different conditions. The model showed that thermal trapping achieves the target temperature at lower concentrations with the same performance, or at higher thermal efficiency for equal concentration. 

Solar thermal trapping at 1000 ºC and above, Device (2024). DOI: 10.1016/j.device.2024.100399. www.cell.com/device/fulltext/S2666-9986(24)00235-7

Gut bacteria enhance cancer immunotherapy in mouse study

Roughly one in five cancer patients benefit from immunotherapy—a treatment that harnesses the immune system to fight cancer. Such an approach to beating cancer has seen significant success in lung cancer and melanoma, among others. Optimistic about its potential, researchers are exploring strategies to improve immunotherapy for cancers that don't respond well to the treatment, with the hope of benefiting more patients.

Cancer immunotherapy employs the body's immune cells to target and destroy tumors. One such treatment uses immune checkpoint inhibitor drugs to unleash the immune system by releasing the natural brakes that keep immune T cells quiet, a feature that prevents the body from harming itself. But some tumors fight back to suppress the attacking immune cells, damping the effectiveness of such inhibitors.

Now, researchers have found, in mice, that a strain of gut bacteria—Ruminococcus gnavus—can enhance the effects of cancer immunotherapy. The study, which appears May 17 in Science Immunology, suggests a new strategy of using gut microbes to help unlock immunotherapy's untapped cancer-fighting potential.

R. gnavus has been found in gut microbiota of cancer patients who respond well to immunotherapy. In clinical trials, fecal transplants from such individuals have helped some unresponsive patients reap immunotherapy's benefits.

Blanda Di Luccia et al, TREM2 deficiency reprograms intestinal macrophages and microbiota to enhance anti-PD-1 tumor immunotherapy, Science Immunology (2024). DOI: 10.1126/sciimmunol.adi5374. www.science.org/doi/10.1126/sciimmunol.adi5374

New technique to freeze brain tissue without harm

A team of medical researchers has developed a technique to freeze and thaw brain tissue without causing damage.
In their study, published in the journal Cell Reports Methods, the group tested bathing brain organoid tissue in candidate chemicals before freezing them using liquid nitrogen.

Prior research has shown that no matter how quickly brain matter is frozen, the freezing and thawing process always causes tissue damage. This has made it more difficult for researchers to study brain matter because research must be conducted immediately after obtaining a tissue sample. In this new effort, the team  found a way around this problem by soaking the tissue in a special solution before freezing.

The work involved dipping or soaking brain organoids (brain tissue grown from stem cells) in candidate compounds and then freezing and thawing them to see how they fared. After many attempts, they found one combination of solutions that worked best—a mix of ethylene glycol, methylcellulose DMSO and Y27632. They named the solution mix MEDY.

The research team then tested MEDY under a variety of conditions to see how well it prevented damage from freezing. The conditions involved changing variables, such as the age of the organoids prior to freezing and how long they were soaked in a MEDY solution. They then allowed the organoids to resume growing after they were thawed for up to 150 days.

The researchers found little difference between organoids that had been frozen and those that had not—even those that had been frozen for as long as 18 months.

As a final test, the research team used their technique on a sample of brain tissue obtained from a live human patient and found that it worked just as well.

The research team suggests that their technique should allow researchers to store brain tissue samples on a scale large enough to allow for new types of brain and nervous system research.

Weiwei Xue et al, Effective cryopreservation of human brain tissue and neural organoids, Cell Reports Methods (2024). DOI: 10.1016/j.crmeth.2024.100777

Microplastics may slow the rate at which carbon is pulled from the sea surface to the depths

Plastics in the ocean do more harm than suffocate turtles, fish and other marine life.

A new study  shows that microplastics may reduce the ability of the ocean to help offset the climate crisis by slowing down the rate at which carbon is taken from the sea surface to the depths.

For millennia, the ocean has been part of a carbon sink process in which dead phytoplankton clump together and fall into the deep ocean in showers of what look like "marine snow". The resulting carbon sequestration is a marine version of how trees and plants on terrestrial Earth take carbon from the atmosphere and store it in soil.

But new research  shows that microplastics in the ocean are slowing the process down by making the "marine snow" more buoyant. Plastics want to float. If phytoplanktons grow on microplastics in biofilms, instead of as free living organisms, that changes the buoyancy of the phytoplankton when they die.

Basically, the plastics are slowing down the sinking rate of the marine snow, which is potentially reducing the efficiency with which the ocean can remove carbon dioxide from the atmosphere.

So microplastics  could be a threat to global scale processes, such as the carbon cycle that is so important for all life.

 Kai Ziervogel et al, Microbial interactions with microplastics: Insights into the plastic carbon cycle in the ocean, Marine Chemistry (2024). DOI: 10.1016/j.marchem.2024.104395

Why digging soil is not good?

Digging disrupts natural processes that keep soil healthy and productive. Minimising cultivation is desirable when trying to grow plants in ways that have the least environmental impact.

Digging the soil bulldozes a number of structures underground. Drainage channels created by worms are destroyed, important fungal networks are broken and carbon that’s been locked in the soil is released into the atmosphere. 

Digging also brings weed seeds closer to the surface, causing them to sprout more readily.

Benefits don’t necessarily include better crops, although some gardeners have reported higher yields. 

Charles Dowding, a champion of no-dig gardening, compared side-by-side beds over eight years. One was dug, the other wasn’t. He reported 100kg of additional produce from the no-dig bed.

So how does a no-dig garden grow? Instead of cultivating the soil, no-dig gardeners cover their beds with a layer of mulch or well-rotted organic matter, either from their own compost bins or the garden centre. 

If the ground is weedy, simply cover it with a few sheets of cardboard.

Then add another layer of compost on top (this is sometimes known as lasagne gardening). 

The weeds will be smothered and plants root into the soil below, which will be enriched by the activity of worms carrying the compost into the underlying soil.

Source: 

https://www.sciencefocus.com/science/no-dig-gardening?utm_campaign=...

Discovery may explain why Egyptian pyramids were built along long-lost Ahramat branch of the Nile

Some 31 pyramids in Egypt, including the Giza pyramid complex, may originally have been built along a 64-km-long branch of the river Nile which has long since been buried beneath farmland and desert. The findings, reported in a paper in Communications Earth & Environment, could explain why these pyramids are concentrated in what is now a narrow, inhospitable desert strip.

The Egyptian pyramid fields between Giza and Lisht, built over a nearly 1,000-year period starting approximately 4,700 years ago, now sit on the edge of the inhospitable Western Desert, part of the Sahara. Sedimentary evidence suggests that the Nile used to have a much higher discharge, with the river splitting into several branches in places. Researchers have previously speculated that one of these branches may have flown by the pyramid fields, but this has not been confirmed.

Eman Ghoneim and colleagues studied satellite imagery to find the possible location of a former river branch running along the foothills of the Western Desert Plateau, very near to the pyramid fields. They then used geophysical surveys and sediment cores to confirm the presence of river sediments and former channels beneath the modern land surface, indicating the presence of a former branch, which they propose naming "Ahramat" (meaning pyramids in Arabic).

The authors suggest that an increased build-up of windblown sand, linked to a major drought which began approximately 4,200 years ago, could be one of the reasons for the branch's migration east and eventual silting up.

The discovery may explain why these pyramid fields were concentrated along this particular strip of desert near the ancient Egyptian capital of Memphis, as they would have been easily accessible via the river branch at the time they were built. Additionally, the authors found that many of the pyramids had causeways that ended at the proposed riverbanks of the Ahramat branch, which they suggest is evidence the river was used for transporting construction materials.

The findings reiterate the importance of the Nile as a highway and cultural artery for ancient Egyptians, and also highlight how human society has historically been affected by environmental change, according to the authors.

Future research to find more extinct Nile branches could help prioritize archaeological excavations along their banks and protect Egyptian cultural heritage, they add.

Eman Ghoneim, The Egyptian pyramid chain was built along the now abandoned Ahramat Nile Branch, Communications Earth & Environment (2024). DOI: 10.1038/s43247-024-01379-7. www.nature.com/articles/s43247-024-01379-7

 Quantum Breakthrough Could Charge Batteries in a Snap

Batteries based on the wave-like nature of charged particles could revolutionize energy storage, potentially cramming in more power at a faster rate than conventional electrochemical cells could ever hope to manage. A new protocol developed by a team of physicists from National Cheng Kung University could transform the basic principles of a fast-charging quantum battery into a practical system, demonstrating ways the superposition of a battery may be used to store energy quickly and efficiently.

Fundamental to quantum physics is the principle that all bits of matter have a wave-like identity that spreads out through space and time.

As counterintuitive as it is to our experience of reality, these waves represent the properties of an object – whether it's an electron, a molecule, a cat, or a whole planet – as a spectrum of possibility referred to as its superposition.

In recent years, researchers have pondered whether one or more objects in a superposition have something in common with the chaotic zip and bounce of heated material in an engine. Tapping into this quantum phenomenon could even provide new ways to transfer and hold energy.

It's a nice idea in concept, but transforming the theory behind quantum heat engines into a working device requires identifying suitable processes that don't waste a whole lot of energy.

The researchers experimentally evaluated two approaches to using the superposition of a particle to charge a hypothetical quantum battery to determine whether its fuzzy state is indeed transferring energy.

In place of an actual battery, the team simply used a trapped ion in a superposition state known as a qubit, which can gain energy as it passes through a reflective space that constrains the kinds of waves passing through.
Sending the ion through a device that split its wave into two beams, the team compared the battery's ability to store energy as separated waves passed through multiple entry points into a single cavity, and then into multiple cavities.
Not only did they find the ion's superposition really can allow for efficient charging, they found the 'many doorways, one room' approach induced an interference effect that could theoretically lead to what they call a "perfect charging phenomenon", which allows a complete conversion of stored energy to work from the quantum battery at any point in the charging process.
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They also demonstrated the process as scalable, with the interference effect persisting even when sending more than one qubit through the cavity.

By carrying out the process on the IBM Quantum Platform and IonQ's quantum hardware, the team demonstrated a proof-of-concept for their protocol, showing a similar system could have the potential to be an energy-effective way of rapidly charging and extracting power from a quantum system.
Though a qubit can simulate the fundamental physics, new methods will be needed to turn the protocol into something more practical and battery-like, meaning it will be a while before you'll be recharging your electric moped in an eyeblink.

Still, the experiment shows there's nothing in the laws of physics that says we can't exploit the quantum landscape for long-life, rapid-charging energy storage.

https://journals.aps.org/prresearch/abstract/10.1103/PhysRevResearc...

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What is the Blood Brain Barrier?

Composition of gut microbiota could influence decision-making

The way we make decisions in a social context can be explained by psychological, social, and political factors. But what if other forces were at work? Scientists show that changes in gut microbiota can influence our sensitivity to fairness and how we treat others. Their findings are published in the journal PNAS Nexus.

The intestinal microbiota—i.e., all the bacteria, viruses and fungi that inhabit our digestive tract—plays a pivotal role in our bodies, well beyond digestive function. Recent research underscores its impact on cognition, stress, anxiety, depressive symptoms, and behaviour; mice raised in a sterile environment, for example, have difficulty interacting with other individuals.

While these findings are promising, most of this research is carried out on animals and cannot be extrapolated to humans. Nor does it allow us to understand what neuronal, immune, or hormonal mechanisms are at work in this fascinating dialogue between brain and intestine: researchers observe a link between the composition of the microbiota and social skills but do not know precisely how one controls the other.

The available data suggests that the intestinal ecosystem communicates with the central nervous system via various pathways, including the vagus nerve. It might also use biochemical signals that trigger the release of neurotransmitters, such as dopamine and serotonin, which are essential for proper brain function.

To determine whether the composition of the human gut microbiota could influence decision-making in a social setting,  researchers used behavioural tests—including the famous "ultimatum game" in which one player is given a sum of money he must split (fairly or unfairly) with a second player, who is free to decline the offer if s/he deems it insufficient. In that case, neither player receives any money.
Refusing the sum of money is equivalent to what we call "altruistic punishment," i.e., the impulse to punish others when a situation is perceived as unfair: for the second player, restoring equality (no one receives any money) sometimes feels more important than obtaining a reward. The ultimatum game is then used as an experimental way of measuring sensitivity to fairness.

To fully exploit this effect, the researchers recruited 101 participants. For seven weeks, 51 took dietary supplements containing probiotics (beneficial bacteria) and prebiotics (nutrients that promote the colonization of bacteria in the gut), while 50 others received a placebo. They all participated in an ultimatum game during two sessions at the beginning and end of the supplementation period.
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The study's results indicate that the group that received the supplements was much more inclined to reject unequal offers at the end of the seven weeks, even when the money split was slightly unbalanced. Conversely, the placebo group behaved similarly during the first and second test sessions.
Moreover, the behavioral change in the supplemented group was accompanied by biological changes: the participants who, at the start of the study, had the greatest imbalance between the two types of bacteria that dominate the gut flora (Firmicutes and Bacteroidetes) experienced the most significant change in the composition of their gut microbiota with the intake of supplements. In addition, they also showed the greatest sensitivity to fairness during the tests.
The researchers also observed a sharp drop in their levels of tyrosine, a dopamine precursor, after the seven-week intervention. For the first time, a causal mechanism is emerging: the composition of the gut microbiota could influence social behavior through the precursors of dopamine, a neurotransmitter involved in brain reward mechanisms.

"It's too early to say that gut bacteria can make us less rational and more receptive to social considerations," conclude the researchers.
However, these new results clarify which biological pathways we must look at. The prospect of modulating the gut microbiota through diet to positively influence decision-making is fascinating. We need to explore this avenue very carefully.

Marie Falkenstein et al, Impact of the gut microbiome composition on social decision-making, PNAS Nexus (2024). DOI: 10.1093/pnasnexus/pgae166

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 Rusting Rivers: The Alarming Impact of Permafrost Thaw on Arctic Rivers

In this video, researchers reveal the startling discovery of over 75 streams and rivers in Alaska's Brooks Range turning orange due to metals released in permafrost thaw. Researchers delve into the consequences of this phenomenon, its impact on aquatic ecosystems and local communities, and the ongoing research efforts to understand and mitigate these changes.

Now Cancer drug pollution is a cause for concern!

As incidence of cancer increases globally, the use of cancer drugs is also growing at a rate of approximately 10 percent per year in developed countries.
Pharmaceuticals significantly contribute to the improvement of human health; however, their environmental impacts have also become a major concern.

Cancer drugs in our ecosystems
Among the many molecules used to treat cancers are cytostatics.

As defined by the United States' National Institutes of Health (NIH), a cystostatic is "a substance that slows or stops the growth of cells, including cancer cells, without killing them."

When a cancer patient takes these drugs, the chemicals in them, including cytostatics, are eventually evacuated through the patients' solid and liquid waste.

A patients' waste ends up in the hospital or domestic wastewater system, where the chemicals in it are not entirely eliminated by end of pipe wastewater treatment plants. These chemicals can then find their way into aquatic ecosystems, and even our drinking water supply, at varying concentrations.

Cytostatic drugs are now classified as contaminants of emerging concern (CECs) due to their hazardous environmental impact.

The message is clear: this problem is only going to get worse as more people use cancer drugs.
The continuous release of pharmaceuticals into aquatic ecosystems (even at low levels) can reduce surface water quality, endanger biodiversity and disrupt ecosystem functioning.
They have a toxic impact on aquatic flora and fauna, especially the fish.

https://www.sciencedirect.com/science/article/abs/pii/S004896972205...

Scientists Confirm Microplastics Now Detected in Human Testicles

We can now add testicles to the list of places where microplastics have managed to spread – alongside human placentas, ancient rocks, clogged arteries, blue whales, baby poop, the wilderness of Antarctica, near the peak of Mount Everest, and the bottom of the ocean.

Research led by the University of New Mexico looked at testicular tissue taken from both dogs and humans, finding microplastics in every sample, with an abundance almost three times higher in humans than in dogs.
The team found an average 122.63 micrograms of microplastics per gram of tissue in canines, and 329.44 micrograms per gram in people.

Besides giving us another sobering reminder of how plastic pollution is penetrating every part of our bodies, the study raises some concerning questions in regards to how these microscopic fragments might impact male fertility.

https://academic.oup.com/toxsci/advance-article-abstract/doi/10.109...

Male and female mice exhibit different empathic behaviors to others' pain

Social interactions are multi-faceted experiences that entail understanding the emotional states of others and responding appropriately. Neuroscientists and psychologists have been studying social interactions for decades, in the hope of understanding their neural and behavioral underpinnings.

A team of researchers  recently carried out a study exploring how male and female mice respond to the pain of other mice. Their findings, published in Neuron, suggest that there are both neurobiological and behavioural differences between the two sexes, specifically in relation to their empathic responses.

Recognizing the affective states of social counterparts and responding appropriately fosters successful social interactions.

The primary objective of the recent study was to delve deeper into how male and female mammals respond to another animal in pain, both in terms of their behavior and brain activity. To do this, they carried out a series of experiments on mice, where two mice were placed in lateral chambers, while an observing mouse was placed in the central section of a common cage.

One of the mice in the lateral chamber was given an injection that caused abdominal pain, while the other two were not administered anything. The researchers monitored the behavior of the mouse in the central part of the cage, who could explore the environment freely and thus whether to interact with the other mice and in what ways.
Initially, both male and female mice moved in their surroundings, displaying similar exploratory behaviors. Yet after a while, particularly towards the end of each experimental trial, the team found that male mice exhibited more grooming behaviors, while female mice demonstrated a social preference for the mouse that was in pain, as they spent more time in its proximity and sniffing it.
"We show that male and female mice emit distinct olfactory cues after experiencing distress," the researchers wrote. "These cues activate distinct neural circuits in the piriform cortex (PiC) and evoke sexually dimorphic empathic behaviours on observers.
Specifically, the PiC → PrL pathway is activated in female observers, inducing a social preference for the distressed counterpart. Conversely, the PiC → MeA pathway is activated in male observers, evoking excessive self-grooming behaviors."
This distinct neural pathway that the researchers found to be activated in male observers originated from non-overlapping PiC neuron populations with different gene expression signatures. Notably, these gene expression signatures are regulated by transcription factors and sex hormones.
Overall, their observations suggest that male and female mice are biologically inclined to respond differently to other mice in pain. While females are more likely to get closer to a peer who is in pain, males tend to respond to another's pain with excessive self-grooming.
The results of this study could soon be explored further and validated in additional experiments. In the future, they could pave the way for the discovery of new neural processes underpinning sex-specific social behaviours.

Shunchang Fang et al, Sexually dimorphic control of affective state processing and empathic behaviors, Neuron (2024). DOI: 10.1016/j.neuron.2024.02.001

Body lice may be bigger plague spreaders than previously thought

A new laboratory study suggests that human body lice are more efficient at transmitting Yersinia pestis, the bacterium that causes plague, than previously thought, supporting the possibility that they may have contributed to past pandemics.

Y. pestis has been the culprit behind numerous pandemics, including the Black Death of the Middle Ages that killed millions of people in Europe. It naturally cycles between rodents and fleas, and fleas sometimes infect humans through bites; thus, fleas and rats are thought to be the primary drivers of plague pandemics.
Body lice—which feed on human blood—can also carry Y. pestis, but are widely considered to be too inefficient at spreading it to contribute substantially to outbreaks. However, the few studies that have addressed lice transmission efficiency have disagreed considerably.

To help clarify the potential role of body lice in plague transmission, Bland and colleagues conducted a series of laboratory experiments in which body lice fed on blood samples containing Y. pestis. These experiments involved the use of membrane feeders, which simulate warm human skin, enabling scientists to study transmission potential in a laboratory setting.

They found that the body lice became infected with Y. pestis and were capable of routinely transmitting it after feeding on blood containing levels of the pathogen similar to those found in actual human plague cases.

They also found that Y. pestis can infect a pair of salivary glands found in body lice known as the Pawlowsky glands, and lice with infected Pawlowsky glands transmitted the pathogen more consistently than lice whose infection was limited to their digestive tract. It is thought that Pawlowsky glands secrete lubricant onto the lice's mouthparts, leading the researchers to hypothesize that, in infected lice, such secretions may contaminate mouthparts with Y. pestis, which may then spread to humans when bitten. These findings suggest that body lice may be more efficient spreaders of Y. pestis than previously thought, and they could have played a role in past plague outbreaks.

 Bland DM, Long D, Rosenke R, Hinnebusch BJ (2024) Yersinia pestis can infect the Pawlowsky glands of human body lice and be transmitted by louse bite. PLoS Biology (2024). DOI: 10.1371/journal.pbio.3002625

Nightmares could be an early warning sign of an autoimmune disease flare-up – new study

Nightmares coming before autoimmune diseases have been found in other neurological diseases. Descriptions of flare-related nightmares in our study often involved being attacked, trapped, crushed or falling. Many were very distressing. One person described them as: “Horrific, like murders, like skin coming off people, horrific.” Another important finding was that these nightmares often came before a disease flare-up, particularly in people who then had hallucinations as part of their disease pattern. This was more likely in people with lupus than the other rheumatological diseases such as inflammatory arthritis. This wasn’t unexpected as lupus is known to affect the brain in some cases. Of the patients also reporting hallucinations, 61% of lupus patients and 34% with other autoimmune rheumatological diseases reported increasing disrupted sleep (mostly nightmares) just before their hallucinations.

https://theconversation.com/nightmares-could-be-an-early-warning-si...

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Newborns whose mother spoke in a mix of languages during pregnancy are more sensitive to a range of sound pitches

It's well established that babies in the womb hear and learn about speech, at least in the third trimester. For example, newborns have been shown to already prefer the voice of their mother, recognize a story that had been repeatedly told to them while in the womb, and tell apart their mother's native language.

What wasn't known until now was how developing fetuses learn about speech when their mother speaks to them in a mix of languages. Yet this is common: there are 3.3 billion bilingual people (43% of the population) worldwide, and in many countries, bilingualism or multilingualism is the norm.

Researchers showed that exposure to monolingual or a bilingual speech has different effects at birth on 'neural encoding' of voice pitch and vowel sounds: that is, how information about these aspects of speech has been initially learned by the fetus.

At birth, newborns from bilingual mothers appear more sensitive to a wider range of acoustic variation of speech, whereas newborns from monolingual mothers seem to be more selectively tuned to the single language they have been immersed in.

Exposure to bilingual or monolingual maternal speech during pregnancy affects the neurophysiological encoding of speech sounds in neonates differently, Frontiers in Human Neuroscience (2024). DOI: 10.3389/fnhum.2024.1379660

Exposure to endocrine-disrupting chemicals in utero associated with higher odds of metabolic syndrome in children

The term 'metabolic syndrome' (MetS) encompasses a group of factors, such as abdominal obesity, hypertension and insulin resistance, that together increase the risk of cardiovascular disease and type 2 diabetes.

A new study suggests that prenatal exposure to a combination of endocrine disrupting chemicals (EDCs) is associated with poorer metabolic health in childhood, which in turn may contribute to an increased risk of metabolic syndrome in adulthood.

EDCs are chemical substances that are so named because of their ability to interfere with the functioning of our hormonal system, growth, energy balance and metabolism and whose exposure, given their ubiquity in our environment, is difficult to escape.

Previous studies have already shown a link between individual exposure to some of these compounds during the prenatal phase and some of the factors that make up the metabolic syndrome, particularly obesity and blood pressure.

The study involved 1,134 mothers and their children from six European countries (Spain, France, Greece, Lithuania, Norway and the United Kingdom), all volunteers from the HELIX (Human Early Life Exposome) cohort. Prenatal exposure to a total of 45 endocrine disruptors was analyzed through blood and urine samples collected from the mothers during pregnancy or from the umbilical cord after birth.

Later, when the children were between 6 and 11 years old, they were followed up, including a clinical examination, interview and collection of biological samples. This yielded data on waist circumference, blood pressure, cholesterol, triglycerides and insulin levels, which were aggregated to obtain a risk index for metabolic syndrome.

Statistical analysis showed that mixtures of metals, perfluoroalkylated and polyfluoroalkylated substances (PFAS), organochlorine pesticides and flame retardants (or PBDEs) were associated with a higher risk of metabolic syndrome. In the case of metals, the association observed was mainly due to the effect of mercury, the main source of which is the intake of large fish.

PFASs are one of the most widely used families of chemical compounds, being used in pesticides, paints, non-stick pans or fast food packaging, among many other common uses. Because of their persistence, they are also known as the "forever chemicals." Also very persistent are organochlorine pesticides, which were already banned in Europe in the 1970s, but to which we are still widely exposed due to their permanence in the environment.

Researchers also observed that associations were stronger in girls for mixtures of PFASs and polychlorinated biphenyls (PCBs), while boys were more susceptible to exposure to parabens. Since endocrine disruptors interfere with sex steroid hormones, these differences fall within what would be expected.

These results suggest that exposure to widespread mixtures of endocrine disruptors during pregnancy may be associated with adverse metabolic health in both boys and girls. This association may contribute to the current increase in the prevalence of lifetime metabolic syndrome, which currently affects a quarter of the adult population, with upward trends evident even among young people
 Prenatal Exposure to Chemical Mixtures and Metabolic Syndrome Risk in Children, JAMA Network Open (2024). DOI: 10.1001/jamanetworkopen.2024.12040

Why the brain can robustly recognize images, even without colour

Even though the human visual system has sophisticated machinery for processing colour, the brain has no problem recognizing objects in black-and-white images. A new study offers a possible explanation for how the brain comes to be so adept at identifying both colour and colour-degraded images.

Using experimental data and computational modeling, the researchers found evidence suggesting the roots of this ability may lie in development. The work has been published in Science

Early in life, when newborns receive strongly limited colour information, the brain is forced to learn to distinguish objects based on their luminance, or intensity of light they emit, rather than their colour. Later in life, when the retina and cortex are better equipped to process colours, the brain incorporates colour information as well but also maintains its previously acquired ability to recognize images without critical reliance on colour cues.

The findings also help to explain why children who are born blind but have their vision restored later in life, through the removal of congenital cataracts, have much more difficulty identifying objects presented in black and white. Those children, who receive rich colour input as soon as their sight is restored, may develop an overreliance on colour that makes them much less resilient to changes or removal of colour information.

Researchers  have observed that limitations in early sensory input can also benefit other aspects of vision, as well as the auditory system.

In 2022, they used computational models to show that early exposure to only low-frequency sounds, similar to those that babies hear in the womb, improves performance on auditory tasks that require analyzing sounds over a longer period of time, such as recognizing emotions. 

Marin Vogelsang et al, Impact of early visual experience on later usage of color cues, Science (2024). DOI: 10.1126/science.adk9587. www.science.org/doi/10.1126/science.adk9587

Nanoparticle vaccines: A potential leap forward in veterinary medicine

Classical vaccines often rely on traditional technologies, such as live attenuated or inactivated pathogens, which carry inherent risks including reduced immunogenicity under certain conditions and potential safety concerns. This has spurred the need for innovative approaches that can provide safer and more effective prophylactic solutions in veterinary medicine.

Self-assembled protein nanoparticles (SAPNs) emerge as a cutting-edge solution, harnessing the power of nanotechnology to revolutionize vaccine design and implementation.

In an article published on 10 May 2024 in Animal Diseases, researchers at Zhejiang University's Institute of Preventive Veterinary Medicine, delve into the development and application of SAPNs and virus-like nanoparticles (VLPs), offering a detailed discussion of their potential in veterinary medicine.

The article focuses on various types of SAPNs, including natural and synthetically designed nanoparticles. These nanoparticles are tailored to enhance the immune system's ability to recognize and respond to pathogens more effectively.

Key highlights include the use of animal virus-derived nanoparticles and bacteriophage-derived nanoparticles, which have shown the potential to elicit strong cellular and humoral responses. The nanoparticles' ability to mimic pathogen structures enables them to trigger a more substantial immune reaction, potentially leading to long-lasting immunity.

Researchers have documented successes in using these nanoparticles to protect against diseases like foot-and-mouth disease and swine fever, showcasing their broad applicability and effectiveness.

Veterinary nanoparticle vaccines have broad implications, with the potential to extend the benefits beyond veterinary applications into human health. The enhanced safety and immunogenicity of these vaccines could lead to the development of advanced vaccines for human use.

Additionally, by reducing the environmental impact of livestock diseases, this technology may contribute to more sustainable agricultural practices globally.

Meiqi Sun et al, Toward innovative veterinary nanoparticle vaccines, Animal Diseases (2024). DOI: 10.1186/s44149-024-00119-w

How a world record 'squeeze' could offer comfort for dark matter hunters

Quantum engineers have developed a new amplifier that could help other scientists search for elusive dark matter particles.

Imagine throwing a ball. You'd expect science to be able to work out its exact speed and location at any given moment, right? Well, the theory of quantum mechanics says you can't actually know both with infinite precision at the same time.

It turns out that as you more precisely measure where the ball is, knowing its speed becomes less and less accurate.

This conundrum is commonly referred to as Heisenberg's uncertainty principle, named after the famous physicist Werner Heisenberg who first described it.

For the ball, this effect is imperceptible, but in the quantum world of small electrons and photons the measurement uncertainty suddenly becomes very significant.

That's the problem being addressed by a team of engineers who have developed an amplifying device that performs precise measurements of very weak microwave signals, and it does so through a process known as squeezing.

Squeezing involves reducing the certainty of one property of a signal in order to obtain ultra-precise measurements of another property.

The team of researchers  have significantly increased the accuracy of measuring signals at microwave frequencies, like those emitted by your mobile phone, to the point of setting a new world record.

The precision of measuring any signal is fundamentally limited by noise. Noise is the fuzziness that creeps in and masks signals, which is something you may have experienced if you've ever ventured out of range when listening to AM or FM radio.

However, uncertainty in the quantum world means there is a limit as to how low noise can be made in a measurement. 

Even in a vacuum, a space void of everything, the uncertainty principle tells us we must still have noise. We call this 'vacuum' noise. For many quantum experiments, vacuum noise is the dominant effect that prevents us from making more precise measurements.

The squeezer produced by the research team now can beat this quantum limit.

The device amplifies noise in one direction, so that noise in another direction is significantly reduced, or 'squeezed.' Think of the noise as a tennis ball, if we stretch it vertically, then it must reduce along the horizontal to maintain its volume. Researchers  can then use the reduced part of the noise to do more precise measurements.

They showed that the squeezer is able to reduce noise to record low levels.

Squeezing is very difficult at microwave frequencies because the materials used tend to destroy the fragile squeezed noise quite easily.

What they've done is a lot of engineering in order to remove sources of loss, which means utilizing very high-quality superconducting materials to build the amplifier.

Part 1

And the team think that the new device could help speed up the search for notoriously elusive particles known as axions, which are so far only theoretical, but proposed by many as the secret ingredient of mysterious dark matter.

 The squeezed noise itself could even be used in future quantum computers.

It turns out that squeezed vacuum noise is an ingredient to build a certain type of quantum computer. Excitingly, the level of squeezing they've achieved is not far off the amount needed to build such a system.

 Arjen Vaartjes et al, Strong microwave squeezing above 1 Tesla and 1 Kelvin, Nature Communications (2024). DOI: 10.1038/s41467-024-48519-3

Part 2

Atomic-resolution imaging shows why ice is so slippery

A team of physicists  has uncovered the reason behind the slipperiness of ice. In their study, published in the journal Nature, the group used atomic force microscopy to get a closer look at the surface of ice at different temperatures.

Prior research and day-to-day experiences  have shown that ice is slippery, even when temperatures are well below the freezing point. Research has suggested this is because of a pre-melt coating that develops at the surface, which serves as a lubricant.

In this new study, the research team used an atomic force microscope fitted with a carbon monoxide atom on its tip to get a better look at the structure of normal ice and its pre-melt coating.

The researchers began by chilling ice inside the microscope chamber to -150°C and then using the microscope to look at its atomic structure. They could see that the internal ice (known as ice Ih), and the ice at the surface were different.

The ice Ih, as expected, was arranged in stacked hexagons. The ice on the surface, by contrast, was only partially hexagonal. The researchers also found defects in the ice at the border between the two types of ice that occurred as the different ice shapes met one another.

The researchers then raised the temperature in the chamber slightly, which resulted in more disorder as the differences in shape became more pronounced. The team then created a simulation showing how such disorder would impact the surface as a whole unit—it showed the disorder expanding all the way across the surface, giving the ice a liquid-like appearance that would be slippery if trod upon.

 Jiani Hong et al, Imaging surface structure and premelting of ice Ih with atomic resolution, Nature (2024). DOI: 10.1038/s41586-024-07427-8

Bizarre bacteria scramble workflow of life
Bacteria have stunned biologists by reversing the usual flow of information. Typically genes written in DNA serve as the template for making RNA molecules, which are then translated into proteins. Some viruses are known to have an enzyme that reverses this flow by scribing RNA into DNA. Now scientists have found bacteria with a similar enzyme that can even make completely new genes — by reading RNA as a template. These genes create protective proteins when a bacterium is infected by a virus. It should change the way we look at the genome.

https://www.biorxiv.org/content/10.1101/2024.05.08.593200v1

Part 1

Strange  bacteria defy textbooks by writing new genes

Micro-ballistics research has shown metals hardening as they are heated, under extreme strain rates.

How gut microbes drive tumour growth
Scientists have long known that obese people have poorer cancer survival rates. Now they have some idea why. A high-fat diet increases the number of Desulfovibrio bacteria in the gut of mice. These release leucine, an amino acid, which encourages the proliferation of a kind of cell that suppresses the immune system. With a suppressed immune system, tumour growth can increase. In breast cancer patients, poorer outcomes were seen for women with higher body-mass index, who also had higher levels of Desulfovibrio bacteria in their gut and leucine in their blood. It’s a provocative finding that will open up new avenues that we should be thinking about.

https://www.pnas.org/doi/10.1073/pnas.2306776121?utm_source=Live+Au...

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Biggest risk factors for disease spread A meta-analysis of five ways that humanity’s environmental footprint spreads disease — biodiversity loss, chemical pollution, climate change, invasive species and deforestation/urbanization — suggests that conserving biodiversity, controlling invasive species and lowering greenhouse-gas emissions would reduce disease spread the most. This evidence can be used in international policy to spur action on climate change and biodiversity loss due to their negative impacts on disease.

https://www.nature.com/articles/s41586-024-07380-6?utm_source=Live+...

Biologists observe recurring evolutionary changes, over time, in stick insects

A long-standing debate among evolutionary scientists goes something like this: Does evolution happen in a predictable pattern or does it depend on chance events and contingency? That is, if you could turn back the clock, as celebrated scientist Stephen Jay Gould (1941–2002) described in his famous metaphor, "Replaying the Tape of Life," would life on Earth evolve, once again, as something similar to what we know now, or would it look very, very different?

Now researchers  report evidence of repeatable evolution in populations of stick insects in the paper "Evolution repeats itself in replicate long-term studies in the wild," in Science Advances. 

The team examined three decades of data on the frequency of cryptic color-pattern morphs in the stick insect species Timema cristinae in ten naturally replicate populations in California. T. cristinae is polymorphic in regard to its body colour and pattern. Some insects are green, which allows the wingless, plant-feeding insect to blend in with California lilac (Ceanothus spinosus) shrubs. In contrast, green striped morphs disappear against chamise (Adenostoma fasciculatum) shrubs.

Hiding among the plants is one of T. christinae's key defenses as hungry birds, such as scrub jays, are insatiable predators of the stick insects.

Bird predation is a constant driver shaping the insects' organismal traits, including coloration and striped vs. non-striped.

Scientists observed predictable 'up-and-down' fluctuations in stripe frequency in all populations, representing repeatable evolutionary dynamics based on standing genetic variation.

A field experiment demonstrates these fluctuations involved negative frequency-dependent natural selection (NFDS), where cryptic colour patterns are more beneficial when rare rather than common. This is likely because birds develop a 'search image' for very abundant prey.

At short time scales, evolution involving existing variations can be quite predictable. You can count on certain drivers always being there, such as birds feeding on the insects.

But at longer time scales, evolutionary dynamics become less predictable.

The populations might experience a chance event, such as a severe drought or a flooding event, that disrupts the status quo and thus, the predictable outcomes.

On long time scales, a new mutation in the species could introduce a rare trait. That's about as close to truly random as you can get.

Rare things are easily lost by chance, so there's a strong probability a new mutation could disappear before it gains a stronghold. 

Indeed, another species of Timema stick insect that also feeds on chamise either never had or quickly lost the mutations making the cryptic stripe trait. Thus, the evolution of stripe is not a repeatable outcome of evolution at this long scale.

Part 1

Replicated, long-term studies from natural populations, including research on the famous Darwin's finches, are rare.

Because most of this work is restricted to one or few populations, it is difficult to draw inferences on repeatability among multiple evolutionary independent populations.

Such studies are challenging to implement not only because they take concerted effort, but also because you can't rush time.

Patrik Nosil et al, Evolution repeats itself in replicate long-term studies in the wild, Science Advances (2024). DOI: 10.1126/sciadv.adl3149. www.science.org/doi/10.1126/sciadv.adl3149

Part 2

How air pollution affects the digestive system

Fine air particles, less than 2.5 micrometers in diameter (PM_2.5), are a major air pollutant linked to various health problems. These particles can travel deep into the lungs and even enter the bloodstream when inhaled. Recent research suggests a major health concern: PM_2.5 exposure can also damage the digestive system, including the liver, pancreas, and intestines.

The work is published in the journal eGastroenterology. This recent research has been focused on how PM2.5 exposure triggers stress responses within the digestive system's cells. These stress responses involve specialized subcellular structures within cells called organelles, such as the endoplasmic reticulum (ER), mitochondria, and lysosomes. When PM2.5 disrupts these organelles, it creates a chain reaction within the cells that can lead to inflammation and other harmful effects.

The liver, a major organ for detoxification and metabolism, is particularly susceptible to PM_2.5 damage. Studies have shown that PM_2.5 exposure can lead to a cascade of problems within the liver, including inflammation, stress responses, and damage to the organelles, and disrupted energy metabolism. These effects can contribute to the development of non-alcoholic fatty liver disease (NASH) and type 2 diabetes.

PM_2.5 exposure does not stop at the liver. It can also harm the pancreas and intestines. Studies have linked PM_2.5 to an increased risk of pancreatic impairment in people with diabetes, as well as damage to intestinal cells and an increase in their permeability. This increased permeability can lead to a variety of digestive issues.

Researchers are exploring whether dietary or pharmaceutical interventions can mitigate PM_2.5 damage. Interestingly, some studies suggest that certain nutrients, like monounsaturated fatty acids and vitamins, may offer some protection against the harmful effects of PM_2.5.

Part 1

Many plants and plant oils are high in monounsaturated fats but low in saturated fats. These include: oils from olives, peanuts, canola seeds, safflower seeds, and sunflower seeds, avocadoes, pumpkin seeds, sesame seeds, almonds,  cashews, peanuts and peanut butter, pecans.

Air pollution is a complex issue with no easy solutions. While research continues mitigating PM2.5 exposure, the current understanding of its impact on the digestive system highlights the far-reaching consequences of air pollution on human health. It underscores the need for continued efforts to reduce air pollution levels and develop strategies to protect ourselves from its detrimental effects.

Kezhong Zhang, Environmental PM2.5-triggered stress responses in digestive diseases, eGastroenterology (2024). DOI: 10.1136/egastro-2024-100063

Part 2

Big brands are 'failing to curb plastic sachet use'

Small plastic sachets commonly used in low- and middle-income countries must be phased out and packaging reuse systems promoted, urge campaigners and waste pickers, as new analysis reveals major corporations have failed to curb their use.

Pocket-sized individual portions of goods ranging from shampoo to instant coffee have become popular in lower-income communities for their affordability.

An estimated 855 billion sachets are sold globally each year with Southeast Asia consuming nearly half of the total and this figure projected to rise to 1.3 trillion by 2027, according to environmental groups.

But the convenience of sachets comes with a heavy environmental cost as they end up as significant contributors to plastic pollution. Their commonly multi-layered design, using different materials, makes them hard to recycle.

Consumer goods giants Unilever, Nestlé and Procter & Gamble are among the biggest contributors to plastic sachet pollution in developing countries in Asia, despite promises to reduce plastic packaging, according to a multi-country environmental audit report.

It said some corporations were trying to deal with the waste problem by burning sachets as fuel, creating further pollution.

Environmental groups in Asia have long been demanding firms to phase out their sachet packaging as the resulting waste is deluging the region's landfills and waters.

Consumers, can you please help by avoiding these small plastic sachet based products?

Source: SciDev.Net

Why some huge stars have disappeared from the sky

When massive stars die, as we understand the Universe, they don't go quietly. As their fuel runs out, they become unstable, wracked by explosions before finally ending their lives in a spectacular supernova.

But some massive stars, scientists have found, have simply vanished, leaving no trace in the night sky. Stars clearly seen in older surveys are inexplicably absent from newer ones. A star isn't exactly a set of keys – you can't just lose it down the back of the couch. So where the heck do these stars go?

A new study has given us the most compelling explanation yet. Some massive stars, suggest an international team led by astrophysicist Alejandro Vigna-Gómez of the Niels Bohr Institute in Denmark and the Max Planck Institute for Astrophysics in Germany, can die, not with a bang, after all, but a whimper.

Their evidence? A binary system named VFTS 243 in the Large Magellanic Cloud, consisting of a black hole and a companion star. This system shows no signs of a supernova explosion that, according to the models, ought to have accompanied the formation of the black hole.

Were one to stand gazing up at a visible star going through a total collapse, it might, just at the right time, be like watching a star suddenly extinguish and disappear from the heavens.

The collapse is so complete that no explosion occurs, nothing escapes and one wouldn't see any bright supernova in the night sky. Astronomers have actually observed the sudden disappearance of brightly shining stars in recent times. Scientists cannot be sure of a connection, but the results they have obtained from analyzing VFTS 243 has brought them much closer to a credible explanation.

Part 1

When a star more massive than about 8 times the mass of the Sun goes supernova, it's extremely messy. The outer layers – most of the star's mass – are explosively ejected into the space around the star, where they form a huge, expanding cloud of dust and gas that lingers for hundreds of thousands to millions of years.

Meanwhile, the star's core, no longer supported by the outward pressure of fusion, collapses under gravity to form an ultradense object, a neutron star or a black hole, depending on the initial star's mass.

These collapsed cores don't always stay put; if the supernova explosion is lopsided, this can punt the core off into space in a natal kick. We can also sometimes trace the core's trajectory back to the cloud of material it ejected as it died, but if enough time has elapsed, the material may have dissipated. But the signs of the natal kick can remain a lot longer.

VFTS 243 is a very interesting system. It consists of a massive star that's around 7.4 million years old and around 25 times the mass of the Sun, and a black hole around 10 times the mass of the Sun.

Although we can't see the black hole directly, we can measure it based on the orbital motion of its companion star – and, of course, we can infer other things about the system. One interesting thing is the shape of the orbit. It's almost circular. This, together with the motion of the system in space, suggests that the black hole did not receive a huge kick from a supernova. The researchers who discovered the black hole back in 2022 suspected as much; now, the work of Vigna-Gómez and his colleagues have confirmed it. There has been a growing body of evidence that suggests that sometimes, massive stars can collapse directly into black holes, without passing supernova or collecting 200 space dollars. VFTS 243 represents the best evidence we have for this scenario to date.

Our results highlight VFTS 243 as the best observable case so far for the theory of stellar black holes formed through total collapse, where the supernova explosion fails and which our models have shown to be possible," says astrophysicist Irene Tamborra of the Niels Bohr Institute. "It is an important reality check for these models. And we certainly expect that the system will serve as a crucial benchmark for future research into stellar evolution and collapse."

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.132.191403

Part 2

Anendophasia: not having any inner speech

In recent years have scientists found that not everyone has the sense of an inner voice – and a new study sheds some light on how living without an internal monologue affects how language is processed in the brain.

This is similar to anauralia, a term researchers coined in 2021 for people who don't have an inner voice, nor can they imagine sounds, like a musical tune or siren.

Focusing on inner voices in a study, a research  team recruited 93 volunteers, half of whom said they had low levels of inner speech, while the other half reported having a very chatty internal monologue. These participants attempted a series of tasks – including one where they had to remember the order of words in a sequence, and another where rhyming words had to be paired together.

It is a task that will be difficult for everyone, but the  hypothesis of the researchers was that it might be even more difficult if people  did not have an inner voice because they have to repeat the words to themselves inside their head in order to remember them.

And this hypothesis turned out to be true.

The volunteers who reported hearing inner voices during everyday life did significantly better at the tasks than those without inner monologues: Inner speakers recalled more words correctly, and matched rhyming words faster. The researchers think this could be evidence that inner voices help people process words.

It's interesting to note that the performance differences disappeared when the volunteers spoke out loud to try and solve the problems they were given. It may be that using an audible voice is just as effective as using an inner voice in these situations.

In two other tasks, covering multitasking and distinguishing between different picture shapes, there was no difference in performance. The researchers take this as a sign that the way inner speech affects behavior depends on what we're doing.

Maybe people who don't have an inner voice have just learned to use other strategies. For example, some said that they tapped with their index finger when performing one type of task and with their middle finger when it was another type of task.

The researchers are keen to emphasize that the differences they found would not cause delays that you would notice in regular conversation. Scientists still at the very early stages in terms of figuring out how anendophasia might affect someone – and likewise anauralia.

https://journals.sagepub.com/doi/10.1177/09567976241243004

Dyson spheres: Astronomers report potential candidates for alien structures, and evidence against their existence

There are three ways to look for evidence of alien technological civilizations. One is to look out for deliberate attempts by them to communicate their existence, for example, through radio broadcasts. Another is to look for evidence of them visiting the solar system. And a third option is to look for signs of large-scale engineering projects in space.

A team of astronomers have taken the third approach by searching through recent astronomical survey data to identify seven candidates for alien megastructures, known as Dyson spheres, "deserving of further analysis." Their research is published in the journal Monthly Notices of the Royal Astronomical Society.

This is a detailed study looking for "oddballs" among stars—objects that might be alien megastructures. However, the authors are careful not to make any overblown claims. The seven objects, all located within 1,000 light-years of Earth, are "M-dwarfs"—a class of stars that are smaller and less bright than the sun.
Dyson spheres were first proposed by the physicist Freeman Dyson in 1960 as a way for an advanced civilization to harness a star's power. Consisting of floating power collectors, factories and habitats, they'd take up more and more space until they eventually surrounded almost the entire star like a sphere.

What Dyson realized is that these megastructures would have an observable signature. Dyson's signature (which the team searched for in the recent study) is a significant excess of infrared radiation. That's because megastructures would absorb visible light given off by the star, but they wouldn't be able to harness it all. Instead, they'd have to "dump" excess energy as infrared light with a much longer wavelength.
Part 1

Unfortunately, such light can also be a signature of a lot of other things, such as a disk of gas and dust, or disks of comets and other debris. But the seven promising candidates aren't obviously due to a disk, as they weren't good fits to disk models.

It is worth noting there is another signature of Dyson sphere: that visible light from the star dips as the megastructure passes in front of it. Such a signature has been found before. There was a lot of excitement about Tabby's star, or Kic 8462852, which showed many really unusual dips in its light that could be due to an alien megastructure.

It almost certainly isn't an alien megastructure. A variety of natural explanations have been proposed, such as clouds of comets passing through a dust cloud. But it is an odd observation. An obvious follow up on the seven candidates would be to look for this signature as well.
The case against Dyson spheres
Dyson spheres may well not even exist, however. I think they are unlikely to be there. That's not to say they couldn't exist, rather that any civilization capable of building them would probably not need to (unless it was some mega art project).

Dyson's reasoning for considering such megastructures assumed that advanced civilizations would have vast power requirements. Around the same time, astronomer Nikolai Kardashev proposed a scale on which to rate the advancement of civilizations, which was based almost entirely on their power consumption.

In the 1960s, this sort of made sense. Looking back over history, humanity had just kept exponentially increasing its power use as technology advanced and the number of people increased, so they just extrapolated this ever-expanding need into the future.

Part 2

However, our global energy use has started to grow much more slowly over the past 50 years, and especially over the last decade. What's more, Dyson and Kardashev never specified what these vast levels of power would be used for, they just (fairly reasonably) assumed they'd be needed to do whatever it is that advanced alien civilizations do.

But, as we now look ahead to future technologies we see efficiency, miniaturization and nanotechnologies promise vastly lower power use (the performance per watt of pretty much all technologies is constantly improving).

A quick calculation reveals that, if we wanted to collect 10% of the sun's energy at the distance the Earth is from the sun, we'd need a surface area equal to 1 billion Earths. And if we had a super-advanced technology that could make the megastructure only 10km thick, that'd mean we'd need about a million Earths worth of material to build them from.
Part3

A significant problem is that our solar system only contains about 100 Earths worth of solid material, so our advanced alien civilization would need to dismantle all the planets in 10,000 planetary systems and transport it to the star to build their Dyson sphere. To do it with the material available in a single system, each part of the megastructure could only be one meter thick.

This is assuming they use all the elements available in a planetary system. If they needed, say, lots of carbon to make their structures, then we're looking at dismantling millions of planetary systems to get hold of it. Now, I'm not saying a super-advanced alien civilization couldn't do this, but it is one hell of a job.

I'd also strongly suspect that by the time a civilization got to the point of having the ability to build a Dyson sphere, they'd have a better way of getting the power than using a star, if they really needed it (I have no idea how, but they are a super-advanced civilization).

Maybe I'm wrong, but it can't hurt to look.

Matías Suazo et al, Project Hephaistos – II. Dyson sphere candidates from Gaia DR3, 2MASS, and WISE, Monthly Notices of the Royal Astronomical Society (2024). DOI: 10.1093/mnras/stae1186

https://phys.org/news/2024-05-dyson-spheres-astronomers-potential-c...

Part 4

By  Simon Goodwin

Scientists report unified framework for diverse aurorae across planets

The awe-inspiring aurorae seen on Earth, known as the Northern and Southern Lights, have been a source of fascination for centuries. Between May 10 and 12, 2024, the most powerful aurora event in 21 years reminded us of the stunning beauty of these celestial light shows.

Recently, space physicists have published a paper in Nature Astronomy that explores the fundamental laws governing the diverse aurorae observed across planets, such as Earth, Jupiter and Saturn.

This work provides new insights into the interactions between planetary magnetic fields and solar wind, updating the textbook picture of giant planetary magnetospheres. Their findings can improve space weather forecasting, guide future planetary exploration, and inspire further comparative studies of magnetospheric environments.

Earth, Saturn and Jupiter all generate their own dipole-like magnetic field, resulting in funnel-canopy-shaped magnetic geometry that leads the space's energetic electrons to precipitate into polar regions and cause polar auroral emissions.

Yet the three planets differ in many aspects, including their magnetic strength, rotating speed, solar wind condition, moon activities, etc. It is unclear how these different conditions are related to the different auroral structures that have been observed on those planets for decades.

Using three-dimensional magnetohydrodynamics calculations, which model the coupled dynamics of electrically conducting fluids and electromagnetic fields, the research team assessed the relative importance of these conditions in controlling the main auroral morphology of a planet.

Combining solar wind conditions and planetary rotation, they defined a new parameter that controls the main auroral structure, which for the first time, nicely explains the different auroral structures observed at Earth, Saturn and Jupiter.

The aurorae at Earth and Jupiter are different. Yet, it is a big surprise that they can be explained by a unified framework.

By advancing our fundamental understanding of how planetary magnetic fields interact with the solar wind to drive auroral displays, this research has important practical applications for monitoring, predicting, and exploring the magnetic environments of the solar system.

This study also represents a significant milestone in understanding auroral patterns across planets that deepen our knowledge of diverse planetary space environments, paving the way for future research into the mesmerizing celestial light shows that continue to capture our imagination.

B. Zhang et al, A unified framework for global auroral morphologies of different planets, Nature Astronomy (2024). DOI: 10.1038/s41550-024-02270-3

Part 2

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