AI's power demands driving toxic air pollution, study finds

Computer processing demands for artificial intelligence, or AI, are spurring increasing levels of deadly air pollution from power plants and backup diesel generators that continuously supply electricity to the fast-growing number of computer processing centers.

This air pollution is expected to result in thousands of premature deaths a year by 2030.

Total public health costs from cancers, asthma, other diseases, and missed work and school days are getting mind boggling. 

Such are findings of a study by UC Riverside and Caltech scientists published online this week on the arXiv preprint server. Yet, these human and financial costs appear overlooked by the tech industry.

Yuelin Han et al, The Unpaid Toll: Quantifying the Public Health Impact of AI, arXiv (2024). DOI: 10.48550/arxiv.2412.06288

What happens in the ocean when two cyclones collide?

In April 2021, two tropical cyclones, Seroja and Odette, collided in the Indian Ocean northwest of Australia. Researchers   now studied how this rare phenomenon affected the ocean.

According to their case study, the rendezvous caused an unusual cooling of the surface water and an abrupt change in the direction of the combined storm. Since the frequency and intensity of tropical cyclones are increasing as a result of global warming, it is possible that such encounters—and thus more extreme air-sea interactions—will become more frequent in the future, they conclude.

Tropical cyclones (TCs) not only whip up air masses in the atmosphere, they also churn up water masses in the areas of the ocean that are in their path. When two cyclones collide and merge, these interactions between the ocean and the atmosphere can intensify considerably.

Researchers reported this  in a paper published in the journal Tellus A: Dynamic Meteorology and Oceanography.

The researchers analyzed the encounter between two relatively weak tropical cyclones in the Indian Ocean in 2021, TC Seroja and TC Odette, and found that effects occurred that have otherwise only been observed with much stronger cyclones. Since the frequency and intensity of tropical cyclones is increasing as a result of global warming, this type of convergence—and the resulting extreme interactions between air and sea—could become more frequent in the future, the study concludes.

Researchers combined satellite data and measurements obtained from ARGO floats and autonomous drifters with numerical modeling. These sources provided the researchers with information about factors such as salinity and water temperatures between the sea surface and depths of up to 2,000 meters as well as data about upward and downward (vertical) flow velocities. In addition to these data, they analyzed upward and downward (vertical) flow velocities using data from numerical models. 

The encounter between the two cyclones lasted for around a week. On 6 April they came within approximately 1,600 kilometers of one another. Seroja first of all stalled the smaller cyclone Odette and then merged with it three days later.

After the two cyclones merged, TC Seroja abruptly changed course by 90 degrees on 9 April. This chain of events not only influenced weather patterns but also triggered a previously unobserved interaction with the ocean underneath.

Part 1

The analysis showed that sea-surface temperatures dropped by 3°C as an after-effect of the merging of the cyclones, and deep, cold water masses were churned upwards towards the surface from a depth of 200 meters in a process known as "upwelling." The cooling effect was "exceptionally high" in relation to the cyclones' intensity, the researchers observed.

The highest wind speeds of around 130 kilometers per hour were reached on 11 April, after the merging of the cyclones, and corresponded to Category 1 on the Hurricane Scale. The observed cooling and the depth of the upwelling, on the other hand, were of a scale observed in Category 4 or 5 hurricanes.
The researchers were particularly surprised by the strength of the upwelling: there were periods when the deep-water masses rose to the sea surface at a speed of up to 30 meters per day. By comparison, the typical upward velocity of the ocean is only between 1 and 5 meters per day.

In this specific case, a downward velocity of the ocean was observed shortly before the cyclones merged. Thanks to satellite technology and autonomous deep-sea ARGO floats, they were able to demonstrate how the rotation of the cyclones transports cold water from the depths of the ocean to the surface.
Although encounters between tropical cyclones during their one to two-week lifespan have been rare to date, according to climate models, the number and intensity of tropical cyclones is likely to increase as a result of global warming—and by extension also the likelihood of full-blown hurricane-force cyclones colliding.
This could result in "the most extreme interactions between the ocean and the atmosphere," the authors of the paper write. The fact that the merging of two cyclones can lead to an abrupt change of course also makes it more difficult to predict how they will behave afterwards.
They also point to another important consequence: "As a result of the interactions of a cyclone with the ocean and the upwelling of cold, deep water, the ocean absorbs additional heat from the air and then transports it to higher latitudes—a crucial process that influences the climate worldwide."
In addition, cyclones also convert thermal energy into mechanical energy which they then transport to higher latitudes as they progress.

Oliver Wurl et al, Intense Cooling of the Upper Ocean with the Merging of Tropical Cyclones: A Case Study in the Southeastern Indian Ocean, Tellus A: Dynamic Meteorology and Oceanography (2024). DOI: 10.16993/tellusa.4083

New antidote could save lives from deadly hydrogen sulfide gas

Hydrogen sulfide, a colorless gas that smells like rotten eggs, is produced naturally from decaying matter. This gas is lethal to breathe in, and hydrogen sulfide present in high concentrations can cause death very rapidly.

Its relative density is also greater than air, causing it to accumulate at lower altitudes and posing an enormous threat to workers at sites, such as manholes, sewage systems and mining operations.

Why is hydrogen sulfide so dangerous? It binds strongly to the heme-containing cytochrome c oxidase (CcO) enzyme and blocks the cellular process of aerobic (oxygen-dependent) respiration.
What is even more concerning is that, as of now, there is no identified antidote that can treat hydrogen sulfide poisoning. Hence, there is an urgent need to develop therapeutic agents that can be stored for long durations and are effective against hydrogen sulfide poisoning immediately.

A study  published online on December 10, 2024, in Scientific Reports has proposed a novel antidote for hydrogen sulfide poisoning.

Researchers decided to tackle this problem by using artificial heme-model compounds that would have a higher affinity towards hydrogen sulfide than the native hemes present in our bodies.

They  have developed and studied synthetic heme-model compounds (hemoCDs) over the last two decades.

In this study, they decided to test if  two of those complexes had the potential to "scavenge" hydrogen sulfide in an aqueous medium. Interestingly, they found that met-hemoCD-I in particular had a very high affinity for hydrogen sulfide under normal physiological conditions—almost 10 times higher than that of human met-hemoglobin.

Met-hemoCD-I was able to convert toxic hydrogen sulfide into nontoxic sulfite and sulfate ions, indicating that it could be used to treat hydrogen sulfide poisoning.

Part 1

To test this antidote, they injected hydrogen sulfide-treated mice with met-hemoCD-I. The results were very promising—mice injected with met-hemoCD-I showed improved survival rates compared to mice that were not given the antidote. Additionally, CcO activity in the brain and heart tissues (which had decreased because of poisoning) recovered and returned to normal.
Another aspect of met-hemoCD-I that makes it a very promising antidote is its demonstrated safety—it was found that injected met-hemoCD-I was excreted in the urine of the rats without undergoing any chemical decomposition in their body.

The results of this study show that hemoCD-Twins could be used as a powerful antidote to treat carbon monoxide, hydrogen cyanide, and now hydrogen sulfide poisoning without the risk of any side effects.
Using hemoCD-Twins, we can provide one powerful solution for multiple gas poisoning, even if the cause of poisoning is unknown.
Clinical trials are about to be started with this antidote.

 Nakagami, A., et al. Detoxification of hydrogen sulfide by synthetic heme model compounds, Scientific Reports (2024). DOI: 10.1038/s41598-024-80511-1

Part 2

Human disruption is driving 'winner' and 'loser' tree species shifts across Brazilian forests, study shows

An international team of researchers examined a unique dataset of more than 1,200 tropical tree species over more than 270 forest plots across six regions of Brazilian Amazon and Atlantic forests that have been altered by people through activities such as deforestation and local disturbances like logging, hunting and burning.

Fast-growing and small-seeded tree species are dominating Brazilian forests in regions with high levels of deforestation and degradation, a study shows. This has potential implications for the ecosystem services these forests provide, including the ability of these "disturbed" forests to absorb and store carbon. This is because these "winning" species grow fast but die young, as their stems and branches are far less dense than the slow growing tree species they replace.

Wildlife species adapted to consuming and dispersing the large seeds of tree species that are being lost in human-modified landscapes may also be affected by these shifts.

Authors of the study, "Winner-loser plant trait replacements in human-modified tropical forests" published in Nature Ecology & Evolution, say their findings highlight the urgent need to conserve and restore tropical forests, prevent degradation, and implement measures to protect and boost populations of the large-bodied birds like toucans and mammals such as spider monkeys that disperse the seeds of "losing" slow-growing large-seeded tree species.

The researchers looked at the overall structure of the landscapes surrounding each forest plot and, using multiple statistical models, they were able to identify the causal effects of habitat loss, fragmentation and local degradation on the composition of forests, as well as identifying the attributes of so-called "winners" and "losers" species.

They found that the tree species dominating landscapes with high forest cover tend to have dense wood and large seeds, which are primarily dispersed by medium to large-bodied animals typical of Brazil's rainforests. 

In contrast, in highly deforested landscapes, where remaining forests face additional human disturbances, these tree species are losing out to so-called 'opportunistic' species, which have softer wood and smaller seeds consumed by small, mobile, disturbance-adapted birds and bats. These species typically grow faster and have greater dispersal capacity.

The researchers found this was happening despite differing geography, climate and land-use contexts.

This study highlights the urgent need to strengthen the conservation and restoration of tropical forests to preserve these vital ecosystems.

Tropical forests constitute the most important reservoir of terrestrial biodiversity. They play a major role in absorbing greenhouse gases and provide essential ecosystem services. Yet they are victims of rapid deforestation and fragmentation, with the loss of 3 to 6 million hectares per year over the last two decades.

Winner-loser plant trait replacements in human-modified tropical forests, Nature Ecology & Evolution (2024). DOI: 10.1038/s41559-024-02592-5

Toxoplasma gondii parasite uses unconventional method to make proteins for evasion of drug treatment, research reveals

A study by  Medicine researchers sheds new light on how Toxoplasma gondii parasites make the proteins they need to enter a dormant stage that allows them to escape drug treatment. The research is published in the Journal of Biological Chemistry.

Toxoplasma gondii is a single-celled parasite that people catch from cat feces, unwashed produce or undercooked meat. The parasite has infected up to one-third of the world's population, and after causing mild illness, it persists by entering a dormant phase housed in cysts throughout the body, including the brain.

Toxoplasma cysts have been linked to behavior changes and neurological disorders like schizophrenia. They can also reactivate when the immune system is weakened, causing life-threatening organ damage.

While drugs are available to put toxoplasmosis into remission, there is no way to clear the infection. A better understanding of how the parasite develops into cysts would help scientists find a cure.

 Researchers have shown that Toxoplasma forms cysts by altering which proteins are made. Proteins govern the fate of cells and are encoded by mRNAs.

But mRNAs can be present in cells without being made into protein. Researchers have  shown that Toxoplasma switches which mRNAs are made into protein when converting into cysts.

Researchers examined the so-called leader sequences of genes named BFD1 and BFD2, both of which are necessary for Toxoplasma to form cysts.

mRNAs not only encode for protein, but they begin with a leader sequence that contains information on when that mRNA should be made into protein.

All mRNAs have a structure called a cap at the beginning of their leader sequence. Ribosomes, which convert mRNA into protein, bind to the cap and scan the leader until it finds the right code to begin making the protein.

What the researchers now found is during cyst formation, BFD2 is made into protein after ribosomes bind the cap and scan the leader, as expected. 

But BFD1 does not follow that convention. Its production does not rely on the mRNA cap like most other mRNAs."

The team further showed that BFD1 is made into protein only after BFD2 binds specific sites in the BFD1 mRNA leader sequence. This is a phenomenon called cap-independent translation, which is more commonly seen in viruses.

Finding it in a microbe that has cellular anatomy like our own was surprising.

Vishakha Dey et al, Cap-independent translation directs stress-induced differentiation of the protozoan parasite Toxoplasma gondii, Journal of Biological Chemistry (2024). DOI: 10.1016/j.jbc.2024.107979

Brain mechanisms underpinning loss of consciousness identified

The shift from an awake state to unconsciousness is a phenomenon that has long captured the interest of scientists and philosophers alike, but how it happens has remained a mystery—until now. Through studies on rats, a team of researchers at Penn State has pinpointed the exact moment of loss of consciousness due to anesthesia, mapping what happens in different brain regions during that moment.

The study has implications for humans as well as for other types of loss of consciousness, such as sleep, the researchers said. They published their results in Advanced Science.

In this study the researchers combined two different methods: electrophysiology studies and functional magnetic resonance imaging (fMRI). By measuring electrophysiological signals—or electrical activity—in the brain very quickly over time, the researchers determined the precise moment that the rat transitioned from an awake state to an unconscious one.  

They next overlaid this time-stamped data with the fMRI map of activity in the whole brain to investigate different regions of the brain during that transition.

They  found that there were three regions in the brain that showed transient changes in their activities during the moment of lost consciousness: the medial prefrontal cortex, the hippocampus and the thalamus.

While these regions have been implicated in unconscious states in the existing scientific literature, this new research was the first to indicate how these regions might interact with each other and what kind of role they might play during the moment of loss of consciousness.

The researchers said previous work also did not indicate whether the activity in those three regions was a cause or an effect of loss of consciousness.

The results suggest that loss of consciousness may be triggered by sequential events in these three regions, while activity increases in other cortical regions may be a consequence, rather than a cause, of loss of consciousness.

The results do provide new insights into the roles of these brain regions in loss of consciousness.

Xiaoai Chen et al, Sequential Deactivation Across the Hippocampus‐Thalamus‐mPFC Pathway During Loss of Consciousness, Advanced Science (2024). DOI: 10.1002/advs.202406320

Early life exposure to toxic chemicals may cause behavioral, psychological problems

Early life exposure to a class of endocrine-disrupting chemicals (EDCs) called polychlorinated biphenyls (PCBs) may lead to behavioral problems in rats, according to a new animal study published in the Journal of the Endocrine Society.

Endocrine-disrupting chemicals (EDCs) are chemicals that mimic, block or interfere with hormones in the body's endocrine system and contribute to endocrine diseases such as cancer, reproductive disorders, obesity and neuroendocrine disorders.

PCBs have been banned for decades but are still persistent in the environment. PCBs are found in contaminated soil, sediment and certain types of fish due to environmental contamination. They have been linked to reproductive and anxiety disorders.

People may be more vulnerable to the endocrine-disrupting effects of PCB exposure during the perinatal period, the time from conception until about one year after giving birth.

Researchers found rats exposed to PCBs during the perinatal period may have developmental and hormonal changes. This study emphasizes and supports previous research on how PCB exposure can affect neurobehavioral outcomes.

The researchers fed a human-relevant PCB mixture or the placebo to about 40 pregnant rats and found the EDCs can reprogram their pups' developing neuroendocrine system and lead to neurobehavioral problems in early life.

Andrea C Gore et al, Neuroendocrine and Developmental Impacts of Early Life Exposure to EDCs, Journal of the Endocrine Society (2024). DOI: 10.1210/jendso/bvae195

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Personalized blood count could lead to early intervention for common diseases

A complete blood count (CBC) screening is a routine exam requested by most physicians for healthy adults. This clinical test is a valuable tool for assessing a patient's overall health from one blood sample.

Currently, the results of CBC tests are analyzed using a one-size-fits-all reference interval, but a new study led by researchers from Mass General Brigham suggests that this approach can lead to overlooked deviations in health. In a retrospective analysis, researchers show that these reference intervals, or setpoints, are unique to each patient.

The study revealed that one healthy patient's CBC setpoints can be distinguishable from 98% of other healthy adults. Results are published in Nature.

Complete blood counts are common tests, and this study suggests CBCs vary a lot from person to person even when completely healthy, and a more personalized and precision medicine approach could give more insight into a person's health or disease.

The long-term stability and patient-specificity of setpoints may provide new opportunities for the personalized management of healthy adults envisioned by precision medicine.

CBC indices are known to shift due to genetics, disease history, and age. But the new study suggests that individual patients have a "setpoint"—a stable value around which measures fluctuate.

By considering CBC setpoints tailored to an individual, clinicians may be able to diagnose diseases in their early stages in adults that appear otherwise healthy, including disorders such as diabetes, heart disease, and kidney failure, all of which can benefit from early intervention.

The study found that for multiple diseases, setpoints produce a two- to four-fold relative risk stratification which is comparable to that provided by common disease screening factors.

The researchers note that these setpoints create new opportunities to investigate the mechanisms of varying CBC thresholds and that the information from CBC setpoints could be used to create more specific treatment plans, including determining if additional screening is needed for an accurate diagnosis.

Drug-free pain relief: Solvent molecules offer non-addictive alternative

Researchers have made a discovery regarding the TRPV1 (transient receptor potential vanilloid 1) ion channel and its role in pain perception. The study reveals how solvent molecules can modulate pain signals, offering a potential pathway for a safer, non-addictive pain management approach.

Pain management is a critical aspect of health care, directly impacting quality of life and overall well-being. The TRPV1 ion channel, essential for pain sensing, undergoes pore expansion when activated, allowing ions and larger molecules to pass through. However, the ability of water molecules to permeate the TRPV1 channel has remained uncertain.

To address this, the research team developed an upconversion nanoprobe capable of distinguishing between ordinary water (H₂O) and deuterated water (D₂O). This advanced technology enabled real-time tracking of water dynamics at both the single-cell and single-molecule levels. 

The study showed that when D₂O passed through the TRPV1 channel, it suppressed pain signal transmission and achieved effective analgesia.

The findings were published in the journal Nature Biomedical Engineering on 21 November 2024.

Administering D₂O to pre-clinical models, the team successfully reduced both acute and chronic inflammatory pain transmission without affecting other neurological responses. This solvent-mediated analgesia mechanism provides an effective, biocompatible, and non-addictive alternative to traditional pain medications, circumventing issues related to drug dependency and tolerance.

The solvent-mediated analgesia mechanism represents an innovative breakthrough in pain relief, potentially driving the development of safer, non-addictive pain therapies for clinical use.

Yuxia Liu et al, Solvent-mediated analgesia via the suppression of water permeation through TRPV1 ion channels, Nature Biomedical Engineering (2024). DOI: 10.1038/s41551-024-01288-2

Air pollution in India linked to millions of deaths

A new study from Karolinska Institutet shows that long-term exposure to air pollution contributes to millions of deaths in India. The research, published in The Lancet Planetary Health, emphasizes the need for stricter air quality regulations in the country.

Air pollution consisting of particles smaller than 2.5 micrometers in diameter, PM_2.5, can enter the lungs and bloodstream and is a major health risk in India. Researchers have now examined the link between these particles and mortality over a 10-year period. The study is based on data from 655 districts in India between 2009 and 2019.

The study  found that every 10 microgram per cubic meter increase in PM_2.5 concentration led to an 8.6% increase in mortality.

The research analyzed the relationship between changes in air pollution levels and mortality. The results show that around 3.8 million deaths over the period can be linked to air pollution levels above India's own air quality guidelines of 40 micrograms per cubic meter.

When compared to the stricter guidelines recommended by the World Health Organization (WHO)—only 5 micrograms per cubic meter—the figure rises to 16.6 million deaths. That's almost 25% of all mortality during the study period.

The study also highlights that the entire population of India lives in areas where PM_2.5 levels exceed WHO guidelines. This means that almost 1.4 billion people are exposed year after year to air pollution that can negatively affect health. In some regions, levels of up to 119 micrograms per cubic meter were measured, significantly higher than what both the WHO and India consider safe.

The results show that current guidelines in India are not sufficient to protect health. Stricter regulations and measures to reduce emissions are of the utmost importance, say the researchers. 

The Indian government has been running a national air pollution control program since 2017 to improve air quality, but the study shows that PM_2.5 concentrations have continued to increase in many areas. The researchers emphasize the importance of both reducing emissions locally and taking into account the long range of air pollution—PM_2.5 particles can travel hundreds of kilometers.

 Estimating the effect of annual PM2-5 exposure on mortality in India: a difference-in-differences approach, The Lancet Planetary Health (2024). DOI: 10.1016/S2542-5196(24)00248-1. www.thelancet.com/journals/lan … (24)00248-1/fulltext

Astronomers discover magnetic loops around supermassive black hole

NGC 1068 is a well-known, relatively nearby, bright galaxy with a supermassive black hole at its center. Despite its status as a popular target for astronomers, however, its accretion disk is obscured by thick clouds of dust and gas. A few light-years in diameter, the outer accretion disk is dotted by hundreds of distinct water maser sources that hinted for decades at deeper structures.

Masers are distinct beacons of electromagnetic radiation that shine in microwave or radio wavelengths; in radio astronomy, water masers observed at a frequency of 22 GHz are particularly useful because they can shine through much of the dust and gas that obscures optical wavelengths.

an international team of astronomers and students set out to observe NGC 1068 with twin goals in mind: astrometric mapping of the galaxy's radio continuum and measurements of polarization for its water masers.

NGC 1068 is a bit of a VIP among active galaxies. It is unusually powerful, with a black hole and an edge-on accretion disk.  And because it is so nearby, it has been really, really well-studied in detail.

By measuring the polarization of water masers as well as the continuum of radio emissions from NGC 1068, the team generated a map revealing the compact radio source now known as NGC 1068* as well as mysterious extended structures of more faint emissions.

Mapping the astrometric distribution of NGC 1068 and its water masers revealed that they are spread along filaments of structure. "It really came out in these new observations, that these filaments of maser spots line up like beads on a string.

The team was stunned to see that there's a clear offset—a displacement angle—between the radio continuum showing the structures at the galaxy's core and the locations of the masers themselves. The configuration is unstable, so the researchers  are probably observing the source of a magnetically-launched outflow.

HSA measurements of the polarization of these water masers revealed striking evidence of magnetic fields. No one has ever seen polarization in water masers outside of our galaxy till now. 

Similar to the looping structures seen on our sun's surface as prominences, the polarization pattern of these water masers clearly indicates that magnetic fields are also at the root of these light-year-scale structures as well.

Looking at the filaments, and seeing that the polarization vectors are perpendicular to them, that's the key to confirming that they are magnetically driven structures. 

Jack F. Gallimore et al, The Discovery of Polarized Water Vapor Megamaser Emission in a Molecular Accretion Disk, The Astrophysical Journal Letters (2024). DOI: 10.3847/2041-8213/ad864f

How bat-origin pathogenic viruses manipulate human cell death and inflammation

A study by researchers at the Indian Institute of Science (IISc) offers insights into cell death regulation by viruses like SARS-CoV-2, and how bats and humans respond differently to tricks that such viruses use to manipulate the host's defense.

The paper is published in the journal iScience.

Zoonotic virus infections pose a serious concern to human health. Bats and birds are among the main reservoirs for several pathogenic viruses that show zoonotic transmission potential. When they reach the human host, these viruses can cause either mild or severe disease.

Host cell death after viral infections is a defense strategy to limit viral spread and mount protective immune responses. However, uncontrolled cell death response can drive excessive tissue damage, leading to disease severity. Scientists have strived to pinpoint how zoonotic viruses that originate from bats manipulate the human host to cause excessive cell death and tissue damage.

The study has uncovered how such viruses mimic components of the host's cell death machinery. They zeroed in on protein motifs called RIP homotypic interaction motifs (RHIMs) that regulate host cell death and inflammation.

Several viruses that originate in bats show mimics of these RHIMs. SARS-CoV-2, for example, contains Nsp13—an enzyme protein critical for virus replication—that has an RHIM similar to those found in humans.

Part 1

The researchers found that Nsp13 promotes robust human cell death activation; mutating the RHIM in Nsp13 therefore enhanced cell survival.

Nsp13 was found to work in synergy with host RHIM proteins called ZBP1 and RIPK3 to promote cell death activation, which might possibly be contributing to the respiratory damage and disease progression seen in COVID-19. The researchers also found that RNA segments in the Z conformation (Z-RNA) in the virus's genome were driving the Nsp13-mediated cell death activation.

Since bats express host RHIM proteins similar to humans, they can serve as the source for RHIM mimics to mutate and evolve, the study suggests. Interestingly, bats show mild clinical symptoms and tissue damage compared to humans despite harboring viruses with RHIM mimics. To understand this conundrum, the authors tested whether and how Nsp13-RHIM regulates bat cell death.
Nsp13 could also activate cell death in bat cells like in human cells. Researchers found the nature of bat cell death to be preferably non-inflammatory and Nsp13-RHIM independent, possibly just enough to clear the viral replication niche but not cause severe inflammation.
These insights on how cell death is regulated differently in bats and humans provide some clues to why some pathogenic viruses are tolerated in bats but cause more severe diseases in humans.
Understanding fundamental differences in cellular responses to viruses in bats and humans is critical to guide pandemic preparedness for such zoonotic virus infections.

Sanchita Mishra et al, Bat RNA viruses employ viral RHIMs orchestrating species-specific cell death programs linked to Z-RNA sensing and ZBP1-RIPK3 signaling, iScience (2024). DOI: 10.1016/j.isci.2024.111444

Part 2

Scientists transform ubiquitous skin bacterium into a topical vaccine

Imagine a world in which a vaccine is a cream you rub onto your skin instead of a needle a health care worker pushes into one of your muscles. Even better, it's entirely pain-free and not followed by fever, swelling, redness or a sore arm. No standing in a long line to get it. Plus, it's cheap.

Thanks to Stanford University researchers' domestication of a bacterial species that hangs out on the skin of close to everyone on Earth, that vision could become a reality.

Staphylococcus epidermidis is a generally harmless skin-colonizing bacterial species. These bugs reside on every hair follicle of virtually every person on the planet.

In recent years, researchers have discovered that the immune system mounts a much more aggressive response against S. epidermidis than anyone expected.

In a study published Dec. 11 in Nature, they zeroed in on a key aspect of the immune response—the production of antibodies. These specialized proteins can stick to specific biochemical features of invading microbes, often preventing them from getting inside of cells or traveling unmolested through the bloodstream to places they should not go.

Individual antibodies are extremely picky about what they stick to. Each antibody molecule typically targets a particular biochemical feature belonging to a single microbial species or strain.

But  would the immune system of a mouse, whose skin isn't normally colonized by S. epidermidis, mount an antibody response to that microorganism if it were to turn up there?

Part 1

Researchers conducted experiments to know this. 

The mice's antibody response to S. epidermidis was "a shocker".Those antibodies' levels increased slowly, then some more—and then even more." At six weeks, they'd reached a higher concentration than one would expect from a regular vaccination—and they stayed at those levels.

It's as if the mice had been vaccinated. Their antibody response was just as strong and specific as if it had been reacting to a pathogen.

The same thing appears to be occurring naturally in humans. The researchers got blood from human donors and found that their circulating levels of antibodies directed at S. epidermidis were as high as anything we get routinely vaccinated against.

This is intriguing. Our ferocious immune response to these commensal bacteria loitering on the far side of that all-important anti-microbial barrier we call our skin seems to have no purpose.

It could boil down to a line scrawled by early-20th-century poet Robert Frost: "Good fences make good neighbors." Most people have thought that fence was the skin. But it's far from perfect. Without help from the immune system, it would be breached very quickly.

The best fence is those antibodies. They're the immune system's way of protecting us from the inevitable cuts, scrapes, nicks and scratches we accumulate in our daily existence.

While the antibody response to an infectious pathogen begins only after the pathogen invades the body, the response to S. epidermidis happens preemptively, before there's any problem. That way, the immune system can respond if necessary—say, when there's a skin break and the normally harmless bug climbs in and tries to thumb a ride through our bloodstream.

Part 2

Step by step, the research team turned S. epidermidis into a living, plug-and-play vaccine that can be applied topically. They learned that the part of S. epidermidis most responsible for tripping off a powerful immune response is a protein called Aap. This great, treelike structure, five times the size of an average protein, protrudes from the bacterial cell wall.

They think it might expose some of its outermost chunks to sentinel cells of the immune system that periodically crawl through the skin, sample hair follicles, snatch samples of whatever is flapping in Aap's "foliage," and spirit them back inside to show to other immune cells responsible for cooking up an appropriate antibody response aiming at that item.
This companion study identifies the sentinel immune cells, called Langerhans cells, that alert the rest of the immune system to the presence of S. epidermidis on the skin.

Aap induces a jump in not only blood-borne antibodies known to immunologists as IgG, but also other antibodies, called IgA, that home in on the mucosal linings of our nostrils and lungs.
Having identified Aap as the antibodies' main target, the scientists looked for a way to put it to work.

Respiratory pathogens responsible for the common cold, flu and COVID-19 tend to get inside our bodies through our nostrils. Normal vaccines can't prevent this. They go to work only once the pathogen gets into the blood. It would be much better to stop it from getting in in the first place.

Part 3

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Discovery and engineering of the antibody response to a prominent skin commensal, Nature (2024). DOI: 10.1038/s41586-024-08489-4 , www.nature.com/articles/s41586-024-08489-4

Skin autonomous antibody production regulates host-microbiota interactions, Nature (2024). DOI: 10.1038/s41586-024-08376-y , www.nature.com/articles/s41586-024-08376-y

substituted the gene encoding a piece of tetanus toxin for the gene fragment encoding a component that normally gets displayed in this giant treelike protein's foliage. Now it's this fragment—a harmless chunk of a highly toxic bacterial protein—that's waving in the breeze."

Would the mice's immune systems "see" it and develop a specific antibody response to it?
And it did!
The mice swabbed with bioengineered S. epidermidis, but not the others, developed extremely high levels of antibodies targeting tetanus toxin. When the researchers then injected the mice with lethal doses of tetanus toxin, the mice given natural S. epidermidis all succumbed; the mice that received the modified version remained symptom-free.

A similar experiment, in which the researchers snapped in the gene for diphtheria toxin instead of the one for tetanus toxin into the Aap "cassette player," likewise induced massive antibody concentrations targeting the diphtheria toxin.

The scientists eventually found they could still get life-saving antibody responses in mice after only two or three applications.

They also showed, by colonizing very young mice with S. epidermidis, that the bacteria's prior presence on these mice's skin (as is typical in humans but not mice) didn't interfere with the experimental treatment's ability to spur a potent antibody response. This implies that their species' virtually 100% skin colonization by S. epidermidis should pose no problem to the construct's use in people.
In a change of tactics, the researchers generated the tetanus-toxin fragment in a bioreactor, then chemically stapled it to Aap so it dotted S. epidermidis's surface. To their surprise, this turned out to generate a surprisingly powerful antibody response.
Topical application of this bug generated enough antibodies to protect mice from six times the lethal dose of tetanus toxin.
it works in mice. Now they are trying to experiment with monkeys.
If things go well, they expect to see this vaccination approach enter clinical trials within two or three years.
The researchers think this will work for viruses, bacteria, fungi and one-celled parasites. Most vaccines have ingredients that stimulate an inflammatory response and make you feel a little sick. These bugs don't do that. Scientists expect that you wouldn't experience any inflammation at all.

Discovery and engineering of the antibody response to a prominent skin commensal, Nature (2024). DOI: 10.1038/s41586-024-08489-4 , www.nature.com/articles/s41586-024-08489-4

Skin autonomous antibody production regulates host-microbiota interactions, Nature (2024). DOI: 10.1038/s41586-024-08376-y , www.nature.com/articles/s41586-024-08376-y

Part 4

**

Tumors grow larger in female fruit flies than males. Here's what that could mean for humans

A study by  researchers has uncovered new insights into how biological sex differences can influence tumor growth. The findings, published in Science Advances, could lead to a better understanding of cancer development and potentially boost efforts to identify a method to stop tumors in their tracks.

The study found that tumors in female fruit flies grew 2.5 times larger than tumors in male fruit flies over the same time period.

Fruit flies are an often used biological research model due to their genetic similarity to humans. In this study, researchers found that the female fruit flies had a stronger innate immune response to the tumors than the males. This response accelerated the growth of tumors by triggering a signaling pathway between cells.

The question now is, do we see this same difference in humans?

Genetically, many of these signaling pathways are well preserved between mammals and insects so this finding is highly relevant to our knowledge of cancer development.

The study found that once a tumor formed, female fruit flies' immune cells (hemocytes) produced more of an inflammatory response signal than their male counterparts. This signal protein, called Eiger, is comparable to a similar protein in mammals, which also regulates immune system and inflammatory responses.

While inflammation is often effective at combating outside invaders, too much inflammation can create an environment that allows tumors to thrive. "We found that in female fruit flies, their stronger immune response caused a downstream cascade of events, culminating in the release of insulin-like peptides which allowed the tumors to accelerate their growth.

The next step is to determine if the bias in tumor growth is regulated by hormones or sex chromosomes, work that may shed further light on why and how tumors grow.

 Xianfeng Wang et al, Sex-dimorphic tumor growth is regulated by tumor microenvironmental and systemic signals, Science Advances (2024). DOI: 10.1126/sciadv.ads4229

Car height, not just speed, matters when pedestrians are hit

Watch out for tall, fast-moving cars. The height of a vehicle, not only its speed, determines its potential danger to a pedestrian, new research shows.

Multiple factors—in this case speed and vehicle height—converge to create negative outcomes on the road.

Measurements of the vehicles involved were used to examine the moderating effect of hood height.

The report involved an analysis of 202 crashes involving people ages 16 and older in cities across the United States. The accidents occurred between 2015 and 2022.

In general, higher vehicle front ends increased the likelihood of both moderate and serious pedestrian injuries, data showed. At 27 mph, the average speed of the crashes, a median-height car had a 60% chance of causing moderate injuries to a pedestrian and a 30% chance of causing serious injuries.

Risks rose along with hood height, however: A median-height pickup—with a front end 13 inches higher than that of a median car—had an 83% chance of causing moderate injuries and a 62% chance of causing serious injuries.

This tracks with earlier IIHS research that found that vehicles with taller front ends are more likely to kill people when they hit them. Compared to smaller cars, large vehicles  such as sports utility vehicles or SUVs, are more likely to harm internal organs.

The increased risk and severity of injury from these vehicles is related to their tendency to inflict more severe injuries higher on the body: to the head, torso, and hip," the study authors explained.

In addition to impact, car size influences how well a driver can see pedestrians.

"Taller vehicles may be more likely to be involved in certain pedestrian crash configurations than shorter ones, potentially due to limitations in driver visibility," the authors said.

In cases where the pedestrian is at the vehicle's front corner, obstructed driver sight lines could make a collision more likely and may reduce pre-impact braking behavior, leading to greater injuries.

What's more, the findings reinforce the importance of redesigning vehicles and roadways to reduce speed in congested areas, the study authors said.

It will take a combination of actions from different corners of the transportation world to improve pedestrian safety.

Monfort, Samuel S., Mueller, Becky C. A modern injury risk curve for pedestrian injury in the United States: the combined effects of impact speed and vehicle front-end height. Insurance Institute for Highway Safety. www.iihs.org/topics/bibliography/ref/2322

Neanderthal-human interbreeding lasted 7,000 years, new study reveals

A new analysis of DNA from ancient modern humans (Homo sapiens) in Europe and Asia has determined, more precisely than ever, the time period during which Neanderthals interbred with modern humans, starting about 50,500 years ago and lasting about 7,000 years—until Neanderthals began to disappear.

That interbreeding left Eurasians with many genes inherited from our Neanderthal ancestors, which in total make up between 1% and 2% of our genomes today.

The genome-based estimate is consistent with archaeological evidence that modern humans and Neanderthals lived side-by-side in Eurasia for between 6,000 and 7,000 years.

The analysis, which involved present-day human genomes as well as 58 ancient genomes sequenced from DNA found in modern human bones from around Eurasia, found an average date for Neanderthal-Homo sapiens interbreeding of about 47,000 years ago. Previous estimates for the time of interbreeding ranged from 54,000 to 41,000 years ago.

The new dates also imply that the initial migration of modern humans from Africa into Eurasia was basically over by 43,500 years ago.

The longer duration of gene flow may help explain, for example, why East Asians have about 20% more Neanderthal genes than Europeans and West Asians. If modern humans moved eastward about 47,000 years ago, as archaeological sites suggest, they would already have had intermixed Neanderthal genes.

The period of mixing was quite complex and may have taken a long time. Different groups could have separated during the 6,000- to 7,000-year period and some groups may have continued mixing for a longer period of time. But a single shared period of gene flow fits the data best.

 Leonardo N. M. Iasi et al, Neandertal ancestry through time: Insights from genomes of ancient and present-day humans, Science (2024). DOI: 10.1126/science.adq3010. www.science.org/doi/10.1126/science.adq3010

Arev Sümer, Earliest modern human genomes constrain timing of Neanderthal admixture, Nature (2024). DOI: 10.1038/s41586-024-08420-x. www.nature.com/articles/s41586-024-08420-x

As wildfires intensify, prolonged exposure to pollution linked to premature death

Researchers have found evidence that living in areas prone to wildfire smoke may negatively impact an individual's life expectancy.

In many parts of the contiguous United States, wildfires are rapidly growing more intense, endangering the humans and wildlife that live in the region. Even once fires are doused, serious health risks remain because of the many adverse effects caused by wildfire smoke and the airborne pollution that the blaze releases into the atmosphere.

Now, scientists  have found that not only is wildfire smoke linked to a shortened lifespan, it also greatly diminishes the positive health impacts of local greenspaces, like forests or parks.

When considering the environment's effect on human life expectancy, we have to account for all kinds of factors. Forests, for example, provide essential ecosystem services to mitigate the impact of wildfire smoke because they can purify the air.

Generally, greenspaces benefit human health by helping to regulate the local ecosystem and climate through capturing carbon dioxide, oxygen production and air filtration as well as by providing open spaces to foster social and community connection. It's why higher levels of greenspaces are usually correlated with higher life expectancies. But because these lush areas can essentially act as fuel for wildfires, their presence is also tightly correlated with higher wildfire smoke emissions.

 Due to its high toxicity, human exposure to this smoke has been known to cause respiratory issues, cardiovascular disease, and an increase in the risk of dementia and hospitalization.

The research was presented this week at the annual meeting of the American Geophysical Union (AGU 2024).

Their findings concluded that for every additional day of smoke exposure, a person's life expectancy could be expected to decrease by about 0.02 years—or about one week.

Conversely, living in a green neighborhood can be beneficial, as even a 1% increase in these spaces can lead to a slight life expectancy increase. While wildfire smoke can negate the benefits of greenspace, the team's results suggest that sociodemographic factors such as income, population density, age and race also significantly impact future life expectancies.

Impacts of Wildfire Smoke PM2.5, Greenspace and Terrain Ruggedness on Life Expectancy in the Contiguous United States. agu.confex.com/agu/agu24/meeti … pp.cgi/Paper/1620628

Polluting shipwrecks

At the bottom of the oceans and seas lie more than 8,500 shipwrecks from two world wars. These wrecks have been estimated to contain as much as 6 billion gallons of oil, as well as munitions, toxic heavy metals and even chemical weapons.

For decades, these wrecks have largely lain out of site and out of mind. But all this time, their structures have been degrading, inexorably increasing the chances of sudden releases of toxic substances into the marine environment.
In parts of the globe, climate change is exacerbating this risk. Rising ocean temperatures, acidification and increasing storminess accelerate the breakdown of these wrecks.

Of course, wrecks from the world wars are far from the only ones to be found at the bottom of the sea, with many others adding to the problem. The cost of addressing this global issue has been estimated at US$340 billion (£261 billion).

How many of these wrecks pose a threat to people's safety, to coastal communities and to the environment? What can be done—and why haven't we done it sooner?

https://theconversation.com/polluting-shipwrecks-are-the-ticking-ti...

Researchers identify amino acid that prevent sporulation in food poisoning

Food poisoning is a common, yet unpleasant, illness caused by eating contaminated items. It is sometimes caused by Clostridium perfringens, a pathogen widely found in soil and the intestinal tracts of animals.

The pathogen multiplies in environments with little oxygen, for example, curry stored in a pot. After ingestion of the pathogen, they form spores in the small intestinal tracts. The toxins produced during spore formation cause diarrhea and abdominal pain, but the underlying mechanism of spore formation has not been fully understood.

Researchers now examined how amino acids are involved in Clostridium perfringens spore formation. The findings were published in Anaerobe.

In this study, they created 21 culture mediums, 20 of which were each deprived of one of the amino acids that make proteins in the human body, to evaluate the pathogen's development.

As a result, the team identified serine as an inhibitor of Clostridium perfringens spore formation. When observed under a microscope, it was found that serine inhibits the pathogen's cell wall from remodeling, which is necessary in the process of becoming a spore.

This is the first reported case where a single amino acid inhibits spore-forming anaerobic bacteria.

Mayo Yasugi et al, Serine affects engulfment during the sporulation process in Clostridium perfringens strain SM101, Anaerobe (2024). DOI: 10.1016/j.anaerobe.2024.102914

Complex bacterial dynamics of urinary tract infections

Urinary tract infections (UTIs) are a major widespread health issue that affects millions of patients globally every year. These infections are not only uncomfortable, but also challenging to treat, as they may often reoccur after the first infection.

A new research study leveraging a mathematical model has now provided a deeper understanding of the complex interactions between different bacterial populations within the bladder and their responses to physiological and therapeutic interventions. This study offers promising pathways for new treatment strategies.

Bacteria are not only present in the urine, but exist in various states in the bladder: free-floating in the bladder lumen, attached to the bladder wall, or even within the bladder's epithelial cells. These different bacterial populations are subjected to different selective pressures, such as immune response and micturition, and antibiotic treatments.

When considering persistent, recurrent infections that need to be treated with antibiotics, there is a higher likelihood that bacteria can adapt and develop resistance during treatment.

This study showed that the different bacterial populations increase the risk of a persistent infection, which then may increase the risk of development of antibiotic resistance. These findings highlight the importance of addressing the diverse bacterial populations and their interactions when treating UTIs.

Another key finding from the study concerns the potential of competitive inoculation as a possible treatment. By introducing a fast-growing, non-pathogenic bacterial strain, pathogenic bacteria can be suppressed. This approach may control the pathogenic population and increase the effectiveness of antibiotic treatment when antibiotics are used in moderation.

This study stresses the importance of considering bacterial compartments in understanding UTIs. By considering the various niches bacteria occupy, and their responses to therapies, this model provides a more realistic view of infection dynamics. It offers valuable insights that could guide and improve future UTI treatments.

Michael Raatz et al, Pathogen non-planktonic phases within the urinary tract impact early infection and resistance evolution, The ISME Journal (2024). DOI: 10.1093/ismejo/wrae191

Paracetamol may not be as safe as perceived in older people, according to a new study

Research, led by experts at the University of Nottingham, has found that repeated doses of paracetamol in people aged 65 and over, can lead to an increased risk of gastrointestinal, cardiovascular and renal complications.

The study, which is published in Arthritis Care and Research, shows that care must be taken when repeated doses are required for chronic painful conditions such as osteoarthritis in older people.

Due to its perceived safety, paracetamol has long been recommended as the first line drug treatment for osteoarthritis by many treatment guidelines, especially in older people who are at higher risk of drug-related complications.

The study analyzed data from the Clinical Practice Research Datalink-Gold. Participants were aged 65 and over with an average age of 75.

Researchers looked at the health records of 180,483 people who had been prescribed paracetamol repeatedly (≥2 prescriptions within six months) during the study. Their health outcomes were then compared to 402,478 people of the same age who had never been prescribed paracetamol repeatedly.

The findings showed that prolonged paracetamol use was associated with an increased risk of peptic ulcers, heart failure, hypertension and chronic kidney disease.

Given its minimal pain-relief effect, the use of paracetamol as a first line pain killer for long-term conditions such as osteoarthritis in older people needs to be carefully considered, say the researchers.

Jaspreet Kaur et al, Incidence of side effects associated with acetaminophen in people aged 65 years or more: a prospective cohort study using data from the Clinical Practice Research Datalink, Arthritis Care & Research (2024). DOI: 10.1002/acr.25471

Scientists innovate breeding strategies to create climate-smart crops

A recent study has reported a novel breeding strategy to rapidly create climate-smart crops that show higher yield under normal conditions and greatly rescue yield losses under heat stress both in staple grain and vegetable crops.

The study,  was published in Cell on 13 December 2024.

 The year 2050 is fast approaching and farm productivity must increase by 60% in order to feed a projected global population of 10 billion. However, current crop production is insufficient and is expected to worsen due to the abiotic-stress burden of climate change.

An increase of 2 °C during the growing season will result in a yield loss of 3–13%. To ensure global food security and overcome breeding bottlenecks, scientists urgently need to develop "climate-smart" crops that achieve higher yields under normal conditions and stable yields under heat stress.

The physiological basis of crop yield and quality is the source-sink relationship. Source tissues (e.g., leaves) are net producers of photoassimilates—i.e., primarily carbohydrates such as sucrose. In contrast, sink tissues (e.g., fruits, seeds, roots, developing flowers, cotton fibers, and storage organs) are net importers, which use or store photoassimilates.

The cell wall invertase gene (CWIN) is the crucial gene regulating the source-sink relationship in plants. The enzyme encoded by this gene unloads and converts sucrose transported from leaves into glucose and fructose within sink organs, where these sugars can be directly absorbed and utilized. Part 1

These sugars are not only essential nutrients for the development of fruits and seeds, but significantly influence the sweetness of fruits and the quality of rice grains.

Heat stress represses CWIN activity and thus disrupts the source-sink balance, resulting in inadequate energy supply in sink organs, reduced reproductive development, and yield penalties.
Researchers developed a strategy based on climate-responsive optimization of carbon partitioning to sinks (CROCS) by rationally manipulating the expression of CWIN genes in fruit and cereal crops.

They precisely knocked-in a 10-bp heat-shock element (HSE) into promoters of CWIN genes in elite rice and tomato cultivars, using self-developed high-efficiency, prime-editing tools. HSE insertion endows CWINs with heat-responsive upregulation in both controlled and field environments to enhance carbon partitioning to rice grains and tomato fruits.

Multi-location and multi-season yield tests on tomatoes under various cultivation conditions, including greenhouses and open fields, showed that under normal conditions, the CROCS strategy increased tomato yields by 14–47%.

Under heat stress, it increased per-plot fruit yield by 26–33% over controls and rescued 56.4–100% of fruit yield losses caused by heat stress. Notably, aspects of fruit quality such as uniformity and sugar content were significantly improved compared to unmodified controls.
In addition, rice cultivars improved by this strategy not only showed a yield increase of 7–13% under normal conditions, but also showed a 25% grain yield increase over controls under heat-stress conditions. Specifically, up to 41% of heat-induced grain losses were rescued in rice.

CROCS is an efficient, versatile, prime-editing based system for rapid crop improvement, which paves the way to rapidly create climate-smart crops by targeted insertion of environment-responsive cis-regulatory elements. The strategy also provides effective gene-editing tools and feasible operational procedures for the fundamental study of plant responses to stress.

The researchers also noted that this breeding strategy has now also been applied to crops such as soybeans, wheat, and corn.

https://english.cas.ac.cn/newsroom/research_news/life/202412/t20241...

Chinese Academy of Sciences

Part 2

Animal dynamics

Microfibers in India's open-air laundries a 'silent disaster'

India's traditional open-air laundries, known as dhobi ghats, hold cultural significance and have provided livelihoods to thousands of washers for generations.

But these communal washing facilities now face a modern environmental challenge, in the form of microfiber—putting aquatic and human health at risk.

Tiny synthetic particles, released from clothes during washing, apart from the chemical detergents used for washing.  are polluting rivers, lakes and other water bodies in India, according to researchers.

Microfiber pollution is a silent yet growing issue. Millions of synthetic fibers are shed from clothes during washing, especially in Dhobi Ghats and commercial laundries, where filtration systems are often absent. These fibers enter water bodies, accumulate over time, and disrupt aquatic ecosystems.

A study by researchers at the National Institute of Technology (NIT) Srinagar, published earlier this year in Environmental Science and Pollution Research, was the first to measure the levels of microfibers in wastewater from Dhobi Ghats and similar commercial laundries.

In Hindi, dhobi means washerman, and ghats are landings or steps leading to the river for bathing or washing. They are part of India's huge informal economy.

But according to the study, dhobi ghats release over 3,200 microfibers per liter of wastewater, while commercial laundries discharge almost 37,000 microfibers per liter.

Most of these particles come from synthetic fabrics such as polyester and nylon, which are non-biodegradable. Once in the water, these microfibers harm aquatic life and eventually make their way into the human food chain.

The conclusion: The rising microfiber pollution is a silent disaster we must address immediately.

As well as microfibers, chemical detergents pose a huge risk to aquatic life and human health, while untreated sewage ends up in many rivers.

People need to be aware of how their laundry choices impact the environment.

Solutions suggested: 

Installing low-cost microfiber filters at Dhobi Ghats. These filters can trap synthetic fibers before the wastewater enters water bodies.

Centralized laundry facilities with proper wastewater treatment systems could also help. These would reduce pollution and improve working conditions for washermen.

Other solutions include using biodegradable detergents and raising awareness about eco-friendly practices among washermen.

Zaid Mushtaq Bhat et al, Microfiber pollution from Dhobi Ghats (open air laundry centers) and commercial laundries in a north Indian city, Environmental Science and Pollution Research (2024). DOI: 10.1007/s11356-023-31700-4

Scientists develop 3D concrete printing method that captures carbon dioxide

Scientists  have developed a 3D concrete printing method that captures carbon, demonstrating a new pathway to reduce the environmental impact of the construction industry.

The innovative method, detailed in the journal Carbon Capture Science & Technology, aims to significantly reduce the carbon footprint of cement—a material responsible for 1.6 billion metric tons of carbon dioxide (CO₂) or about 8% of global CO₂ emissions—through lower material usage, reduced construction time, and labor requirements.

The newly developed 3D concrete printing process involves injecting steam and CO2, captured as the by-products of industrial processes, into the mixing concrete, which then directly incorporates and stores the CO2 in the concrete structure. Results have shown that the CO2 and steam injection method improved the mechanical properties of the concrete, offering increased strength compared to conventional 3D printed concrete.

Sean Gip Lim et al, Carbon capture and sequestration with in-situ CO2 and steam integrated 3D concrete printing, Carbon Capture Science & Technology (2024). DOI: 10.1016/j.ccst.2024.100306

Cognitive flexibility: How neural variability shapes decision-making in different brains

Research published in Nature has revealed that neural computations in different individuals can be implemented to solve the same decision-making tasks, even when the behavioral outcomes appear identical.

Cognitive flexibility is the ability of a brain to adapt its response to the same external stimulus, like light or sound, based on different contexts. For example, if someone calls your name in a crowded room, you must focus on the sound's location or the voice characteristics to identify the person. This flexibility in selecting and processing relevant information while ignoring irrelevant information is crucial for survival and effective interaction with our environment. The researchers aimed to develop a framework to explain how neural networks compute context-dependent selection, and link neural and behavioral variability. They began by training rats to perform decision-making tasks based on external auditory cues. Their decision-making was based on a set of two alternating rules.

The location rule required the rats to respond to the location of a series of auditory clicks. On the other hand, the frequency rule required them to respond to the frequency of the clicks while ignoring their location.

A context cue before each rule informed the rats of which rule to follow. The rules switched rapidly, requiring the rats to adjust their decision-making process quickly.
Rats can learn to solve this task with very high accuracy, and analysis of their behavior and neural activity over many trials allows us to precisely characterize the mechanisms they are using to select the context-relevant stimuli and make the right decisions
Part 1

To understand how the rats processed each task, the researchers measured the rats' neural activity. The measurements were recorded from the frontal orienting fields (FOF), a region of the brain involved in decision-making and orienting responses to external stimuli, especially in terms of adjusting behavior based on context. This would later help to understand the mechanisms at play in content-dependent decision-making.
The researchers developed a theoretical framework to explain how the brain computes context-dependent decision-making. This was based on three possible dynamic solutions for how the brain might process information.

Next, the researchers developed RNNs to simulate how each solution could be used to solve the task presented to the rats. RNNs are a type of artificial neural network used in machine learning, designed to handle sequential data—like time series or patterns that change over time.

"RNNs can be trained to solve the same task as the rats using different mechanisms.
The researchers found that not all brains use the same mechanism to solve a task, even if the same outcome is achieved.

"Measurements of brain dynamics differed between individual animals, suggesting that different brains use different mechanisms to solve the same task, even though on the surface it might look like their behavior is very similar. This result is important because it has been very hard to study this kind of individual variability before.
Additionally, the team found a strong correlation between variability in neural responses and behavioral outcomes, identifying neural signatures for these correlations. The results from the RNN models matched the observed brain activity in the rats, confirming their finding of a high degree of individual variability in handling the same task.

Marino Pagan et al, Individual variability of neural computations underlying flexible decisions, Nature (2024). DOI: 10.1038/s41586-024-08433-6

Part 2

Patients whose allergies cause the sniffles have different fungi living in their noses, scientists discover

Several people have allergies that cause a runny nose. This respiratory disease, formally called allergic rhinitis and frequently associated with asthma, is a common problem around the world, and the upper airway is a key target for research into the underlying disease processes.

Now a global team of researchers has discovered that patients with allergy-induced sniffles and asthma have different fungal colonies or mycobiomes in their noses, suggesting potential lines of inquiry for future treatments.

This may suggest that allergic rhinitis increases the diversity and changes the composition of the upper airway's microbiome.

Allergic rhinitis causes sneezing, itching, inflamed nasal mucous membranes, and a blocked and runny nose. It's often comorbid with asthma, which also involves inflammation and obstructed airways. Allergic rhinitis and asthma may even be different aspects of the same airway inflammatory disease, which makes it critical to identify the links between them and the underlying causes.

Part 1

To study the nasal mycobiome, the researchers recruited 214 participants from among children and young adults attending an immunology and asthma clinic in Porto. 155 patients had both allergic rhinitis and asthma, while 47 were only diagnosed with allergic rhinitis and 12 with asthma. 125 healthy controls were also enrolled.

The scientists took samples from the participants' noses using nasal swabs and sequenced the fungal DNA they found, focusing on two specific regions to identify different fungal species and develop an overview of each participant's mycobiome. After quality controls, they had 306 samples to work with.

They then used network analysis to understand the relationships between different genera of fungi, and to characterize the different communities of fungi present in healthy and sick participants. They also investigated the function of different fungi, looking at the metabolic pathways they affect, to try to understand the implications of any mycobiome variation between the groups of patients.
The most common families of fungi across all samples were Ascomycota and Basidiomycota. In these two families, 14 genera dominated the mycobiomes.

"Among these dominant genera we detected common fungi that have been recognized in humans as allergenic or opportunistic pathogenic fungi.
This suggests that the nasal cavity is a major reservoir for fungi that could be involved in allergic rhinitis and asthma.
There was a very clear and statistically significant difference between the patients with respiratory diseases and the healthy controls—and no significant difference between the different groups of patients with respiratory diseases. The patients with respiratory diseases had more diverse and richer mycobiomes.

The fungi sampled from patients with both allergic rhinitis and asthma also showed more evidence of connections between them than the fungi in the healthy participants' noses and those who only had allergic rhinitis. This could indicate that the fungi are affecting the nose's immune environment.
Part 2

The scientists also found that three metabolic pathways associated with the production of a building block for DNA and RNA—5-aminoimidazole ribonucleotide or AIR—were overabundant in the mycobiome of patients with allergic rhinitis and asthma. AIR is linked to purine production, necessary for energy metabolism and DNA synthesis.

The nasal mycobiome of individuals with allergic rhinitis and asthma differs from that of healthy controls in composition, structure and function, Frontiers in Microbiology (2024). DOI: 10.3389/fmicb.2024.1464257

Part 3

Elevated levels of 'forever chemicals' found in several smartwatch wrist bands

Smartwatches and fitness trackers have become ubiquitous forms of wearable tech, accompanying many people throughout their days (and nights). But they may expose the skin to so-called forever chemicals in the process. More expensive wristbands made from fluorinated synthetic rubber revealed particularly high amounts of one forever chemical, perfluorohexanoic acid (PFHxA), according to a study published in Environmental Science & Technology Letters.

Per- and polyfluoroalkyl substances (PFAS) are a group of chemicals that are very good at two things—lasting seemingly forever in the environment and repelling water, sweat and oil. Because of the latter properties, manufacturers include these chemicals in many consumer products, such as stain-resistant bedding, menstrual products and fitness wear, including smartwatch and fitness tracker wristbands.

The bands contain fluoroelastomers, synthetic rubbers made from chains of PFAS, to create a material that avoids discoloration and repels dirt. Though this durability makes the bands great for sweaty workouts, it might also present a source of these compounds to get under the wearer's skin—literally.

Researchers investigated several commercially available watchbands for the presence of fluorine as well as 20 individual PFAS.

The team screened 22 wristbands from a range of brands and price points, most of them newly purchased but a few previously worn. All of the 13 bands advertised as being made from fluoroelastomers contained the element fluorine. But two of the nine bands that did not advertise being made from fluoroelastomers also contained fluorine, which indicates the potential presence of PFAS.

Of those tested, wristbands that cost more than $30 contained more fluorine than those under $15. Next, following a chemical extraction, all the wristbands were checked for 20 different PFAS. PFHxA was found to be the most common, appearing in nine of 22 tested wristbands. The median PFHxA concentration was found to be nearly 800 parts per billion (ppb), and one sample exceeded 16,000 ppb.

The researchers suggest that the large amounts of PFHxA found in the wristbands may be a result of the compound being used as a surfactant during the fluoroelastomer manufacturing process.

 Recent studies suggest that a significant percentage of these forever chemicals could pass through human skin under normal conditions.

The research team recommends purchasing lower-cost wristbands made from silicone. If the consumer wishes to purchase a higher-priced band, they suggest that they read the product descriptions and avoid any that are listed as containing fluoroelastomers.

Presence of Perfluorohexanoic Acid in Fluoroelastomer Watch Bands, Environmental Science & Technology Letters (2024). DOI: 10.1021/acs.estlett.4c00907. pubs.acs.org/doi/abs/10.1021/acs.estlett.4c00907

Microplastics in the air may be leading to lung and colon cancers

Tires and degrading garbage shed tiny pieces of plastic into the air, creating a form of air pollution that  researchers suspect may be causing respiratory and other illnesses.

A review of some 3,000 studies implicates these particles in a variety of serious health problems. These include male and female infertility, colon cancer and poor lung function. The particles also may contribute to chronic pulmonary inflammation, which can increase the risk of lung cancer.

These microplastics are basically particulate matter air pollution, and we know this type of air pollution is harmful, say the researchers.

Microplastics are less than 5 millimeters—smaller than a grain of rice—and they are ubiquitous in the environment. Each year, companies around the world produce nearly 460 million metric tons of plastic. That is projected to reach 1.1 billion by 2050.

A major source of plastic in the air is driving. Friction wears down tires along with the road surface, sending plastic fragments into the air.

This new paper is the first systematic review of microplastics using gold standard methods approved by the National Academy of Sciences.

Researchers  urge regulatory agencies and policy leaders to consider the growing evidence of health harms from microplastics, including colon and lung cancer.

 Environmental Science & Technology (2024). 

Effects of Microplastic Exposure on Human Digestive, Reproductive, and Respiratory Health: A Rapid Systematic Review

doi.org/10.1021/acs.est.3c09524

What is metformin's secret sauce? New study shows how this drug works in living animals

Millions of people take metformin, a type 2 diabetes medication that lowers blood sugar. The drug has also been shown to slow cancer growth, improve COVID outcomes and reduce inflammation. So scientists are trying to determine how, exactly, the drug works.

A new study has provided direct evidence in mice that the drug reversibly cuts the cell's energy supply by interfering with mitochondria to lower glucose levels. More specifically, metformin blocks a specific part of the cell's energy-making machinery called mitochondrial complex I. In doing so, the drug can target cells that may be contributing to disease progression without causing significant harm to normal, healthy cells.

Colleen Reczek et al, Metformin targets mitochondrial complex I to lower blood glucose levels, Science Advances (2024). DOI: 10.1126/sciadv.ads5466. www.science.org/doi/10.1126/sciadv.ads5466

Your lifestyle may be aging your brain faster than you think

New research has found a relationship between lifestyle choices that affect dementia risk and early signs of aging in the brain.

Researchers discovered reduced white matter volume and an imbalance in electrical activity in the brains of participants whose lifestyle factors were linked to a higher risk of dementia.

It appeared factors like dietary habits, sleep patterns and physical activity levels, could already be affecting the brain before any signs of cognitive decline.

In the same way that sun safety choices can present on your skin and affect your future cancer risk, the researchers found a relationship between a person's lifestyle choices, their brain health, and their future dementia risk.

Even in very healthy older adults, higher modifiable dementia risk was connected to two major indicators of brain health—white and the brain's ability to balance its electrical activity.

It appears that the dementia risk of your daily choices is "painted" onto the canvas of your brain. The good news? The paint is still wet, and you're holding the brush.

Thomas Pace et al, Modifiable dementia risk associated with smaller white matter volume and altered 1/f aperiodic brain activity: cross-sectional insights from the LEISURE study, Age and Ageing (2024). DOI: 10.1093/ageing/afae243

This new  sunscreen uses TiO₂ nanoparticles to cool skin while blocking UV rays

Wearing sunscreen is important to protect your skin from the harmful effects of UV radiation but doesn't cool people off. However, a new formula, described in Nano Letters, protects against both UV light and heat from the sun using radiative cooling. The prototype sunblock kept human skin up to 11 degrees Fahrenheit (6 degrees Celsius) cooler than bare skin, or around 6 °F (3 °C) cooler than existing sunscreens.

Radiative cooling involves either reflecting or radiating heat away from something, cooling whatever's underneath. It is already used to create cooling fabrics and coatings that could both cool and heat homes, among other applications.

Some passive radiative cooling technologies rely on an ingredient called titanium dioxide (TiO2) because the whitish substance reflects heat. TiO2 particles are also used in mineral sunscreens to reflect UV light, but the particles aren't the right size to produce a cooling effect. So, researchers  wanted to tune the size of TiO2 nanoparticles to create a sunscreen that works both as a UV protector and a radiative cooler.

The team created their sunblock by combining six ingredients: TiO2 nanoparticles, water, ethanol, moisturizing cream, pigments, and a common silicone polymer used in cosmetics called polydimethylsiloxane. By carefully adjusting the sizes of the TiO2 nanoparticles, they produced a material that reflects both UV light and solar heat, imparting the cooling ability.

The new formulation demonstrated an SPF of about 50, water resistance and continued efficacy after 12 hours of simulated sunlight exposure with a xenon lamp. Additionally, when applied to both animal and human skin, the product didn't cause irritation.

In tests on people in a hot and humid outdoor environment, the new radiative cooling sunscreen was found to keep the participants' skin up to 10.8 °F (6.0 °C) cooler than bare skin, and up to 11.0 °F (6.1 °C) cooler than commercially available sunscreens. The formulation is inexpensive, costing only $0.92 for 10 grams of the mixture—on par with sunblocks already on the market.

Jiaqi Xu et al, High-Performance Radiative Cooling Sunscreen, Nano Letters (2024). DOI: 10.1021/acs.nanolett.4c04969

Climate change could trigger more earthquakes, study suggests

A recent  study published in the journal Geology demonstrates that climate change can affect the frequency of earthquakes, adding to a small but growing body of evidence showing that climate can alter the seismic cycle.

Geoscientists analyzed the Sangre de Cristo Mountains in southern Colorado, a range with an active fault along its western edge. Their results indicate that the fault had been held in place under the weight of glaciers during the last ice age, and as the ice melted, slip along the fault increased. This suggests that earthquake activity along a fault could increase as glaciers recede.

Climate change is happening at a rate that is orders of magnitude faster than we see in the geologic record.

We see this in the rapid mountain glacial retreats in Alaska, the Himalayas and the Alps. In many of these regions, there are also active tectonics, and this work demonstrates that as climate change alters ice and water loads, tectonically active areas might see more frequent fault movements and earthquakes due to rapidly changing stress conditions.

It is well known that climate adjusts to seismic changes in the Earth's surface. The tectonic uplift of mountain ranges alters atmospheric circulation and rainfall, for example.

The Sangre de Cristo Mountains were covered with glaciers during the last ice age. Using remote-sensing and field data, the researchers reconstructed where the ice was, calculated the load that would have been pushing on the fault, and then measured displacement of the fault, or how much it had shifted.

The study found that fault slip rates have been five times faster since the last ice age than during the time the range was covered in glaciers. This research may preview how other glacier-adjacent faults will respond to a warming climate.

And this is compelling evidence. 

The research adds to our understanding of what drives earthquakes, which is important for hazard assessment. Faults in areas with rapidly retreating glaciers or evaporating large bodies of water may need to be monitored for increasing earthquake activity.

Cecilia Hurtado et al, Exploring the impact of deglaciation on fault slip in the Sangre de Cristo Mountains, Colorado, USA, Geology (2024). DOI: 10.1130/G52661.1

Adding sweetener to coffee enhances 'night-owl' effects of caffeine, research reveals

Adding sugar or artificial sweeteners to coffee disrupted the body clocks in mice more than coffee on its own, researchers have found, with it causing day and night to be reversed in some mice. If this holds for humans as well, adding sweetener to coffee would have significant health ramifications.

If you need to perk yourself up in the morning, or stay up late to get some work or a school assignment done, most people will make themselves a cup of coffee or grab an energy drink containing caffeine. These "night-owl" effects of that perky chemical are far from unknown.

A myriad of epidemiological studies have demonstrated how night-oriented people tend to drink more caffeinated beverages than morning people, and experiments on animals and cells have shown how caffeine works to extend the waking period of the internal body clock.

But a group of researchers accidentally discovered that changes in the activity rhythms of mice were affected even more strongly when they mixed caffeine with sugar or other sweeteners.

The mice that had consumed the caffeine-sweetener mix experienced a very long "free-running" sleep-wake period of 26–30 hours, and some even switched from a nocturnal circadian rhythm to a daytime-based one.

These effects continued to happen even when the mice were subjected to persistent darkness. This latter phenomenon suggests that the caffeine-sweetener effect is operating independently of the central regulator of the internal body clock, the suprachiasmatic nucleus (SCN), which lies in the hypothalamus in the brain. That central regulator itself is normally governed by light and the natural day-night cycle, and it in turn ensures a synchronization of clocks situated in organ tissue elsewhere in the body.

The researchers think that the combination of caffeine and sweetness may be creating a conflicting signal within the body possibly mediated by another famous chemical, dopamine. Both caffeine and sweeteners activate the reward system in the brain, leading to the release of dopamine. It is this double hit of dopamine that could be contributing to the emergence of the long-period activity rhythms.

The researchers now aim to investigate further the possible dopamine link and see whether the boost to caffeine produced by a sweetener is replicated in humans. While this initial study only looked at the effects in mice, the findings may have important implications for our understanding of how sweetened caffeine affects human health.

 Yu Tahara et al, Sweetened caffeine drinking revealed behavioral rhythm independent of the central circadian clock in male mice, npj Science of Food (2024). DOI: 10.1038/s41538-024-00295-6

New discovery pinpoints when good cholesterol becomes harmful

We have heard till now that good cholesterol is good. But wait ....

Researchers have discovered that certain components of so-called "good" cholesterol—high-density lipoproteins (HDL)—may be associated with an increased prevalence of cardiovascular disease.

Surprized? Yes, new data asks for revisits.

Yes, not all cholesterol is born the same. What is not commonly recognized is that each type of cholesterol has two forms—free cholesterol, which is active and involved in cellular functions, and esterified, or bound, cholesterol, which is more stable and ready to be stored in the body. Too much free cholesterol, even if it is in HDL, could contribute to heart disease. Hmmm!

In pre-clinical studies, the research team discovered that HDL with a high content of free cholesterol is likely dysfunctional. To validate their findings and prove their hypothesis, they are currently at the halfway point of the Houston Heart Study in which they will be studying 400 patients with a range of plasma HDL concentrations.

The most surprising finding from  this new study thus far is that there is a strong link between the amount of free cholesterol in HDL and how much of it accumulates in white blood cells called macrophages, which can contribute to heart disease.

While it was previously thought that the transfer of free cholesterol to HDL was beneficial for heart health by removing excess cholesterol from tissues, the new data shows that in the context of high plasma HDL concentrations, the reverse is true, wherein free cholesterol transfer from HDL to the white blood cells in blood and tissues could actually raise one's risk for cardiovascular disease.

The researchers say once they reach their immediate goal of showing that excess free cholesterol in HDL is associated with excess cardiovascular disease, they plan to develop new diagnostics and treatments for managing heart disease, as well as use HDL-free cholesterol as a biomarker to identify patients requiring HDL-lowering therapies.

Now that you are confused, what should you do?

Wait for more clarification and confirmation studies while still taking care of your heart's health.

Dedipya Yelamanchili et al, HDL-free cholesterol influx into macrophages and transfer to LDL correlate with HDL-free cholesterol content, Journal of Lipid Research (2024). DOI: 10.1016/j.jlr.2024.100707

Squirrels Have Developed a Taste For Meat in Surprise Discovery
Squirrels might look like adorable, nut-hoarding furballs, but some are ruthless predators that hunt, tear apart, and devour voles.

That's the startling finding of a new study published this week in the Journal of Ethology – the first to document widespread carnivorous behavior in these seemingly innocent creatures.
The observations were made this summer, during the 12th year of a long-term study conducted at Briones Regional Park in Contra Costa County, California.

Between June and July, researchers recorded 74 interactions involving California ground squirrels and voles, with 42 percent of them involving active hunting of their fellow rodents.
It was previously known that as many as 30 species of squirrels opportunistically consume meat, ranging from small fish to birds. However, it was unclear whether this behavior stemmed from scavenging or active predation.

The new study is the first to confirm that hunting is, in fact, a common behavior.

Researchers observed squirrels crouching low to the ground before ambushing their prey, though more often, they chased voles, pounced, and delivered a neck bite followed by vigorous shaking.

The study also found that the squirrels' carnivorous behavior peaked during the first two weeks of July, coinciding with a surge in vole populations.

https://link.springer.com/article/10.1007/s10164-024-00832-6

Dark energy 'doesn't exist' so can't be pushing 'lumpy' universe apart, physicists say

One of the biggest mysteries in science—dark energy—doesn't actually exist, according to researchers looking to solve the riddle of how the universe is expanding.

Their analysis has been published in the journal Monthly Notices of the Royal Astronomical Society Letters.

For the past 100 years, physicists have generally assumed that the cosmos is growing equally in all directions. They employed the concept of dark energy as a placeholder to explain unknown physics they couldn't understand, but the contentious theory has always had its problems.

Now a team of physicists and astronomers are challenging the status quo, using improved analysis of supernovae light curves to show that the universe is expanding in a more varied, "lumpier" way.

The new evidence supports the "timescape" model of cosmic expansion, which doesn't have a need for dark energy because the differences in stretching light aren't the result of an accelerating universe but instead a consequence of how we calibrate time and distance.

It takes into account that gravity slows time, so an ideal clock in empty space ticks faster than inside a galaxy.

The model suggests that a clock in the Milky Way would be about 35 percent slower than the same one at an average position in large cosmic voids, meaning billions more years would have passed in voids. This would in turn allow more expansion of space, making it seem like the expansion is getting faster when such vast empty voids grow to dominate the universe.

These findings show that we do not need dark energy to explain why the universe appears to expand at an accelerating rate. Dark energy is a misidentification of variations in the kinetic energy of expansion, which is not uniform in a universe as lumpy as the one we actually live in.

The research provides compelling evidence that may resolve some of the key questions around the quirks of our expanding cosmos.

With new data, the universe's biggest mystery could be settled by the end of the decade, the physicists say.

Part 1

Dark energy is commonly thought to be a weak anti-gravity force which acts independently of matter and makes up around two thirds of the mass-energy density of the universe.

The standard Lambda Cold Dark Matter (ΛCDM) model of the universe requires dark energy to explain the observed acceleration in the rate at which the cosmos is expanding.

Scientists base this conclusion on measurements of the distances to supernova explosions in distant galaxies, which appear to be farther away than they should be if the universe's expansion were not accelerating.

However, the present expansion rate of the universe is increasingly being challenged by new observations.

Firstly, evidence from the afterglow of the Big Bang—known as the Cosmic Microwave Background (CMB)—shows the expansion of the early universe is at odds with current expansion, an anomaly known as the "Hubble tension."

In addition, recent analysis of new high precision data by the Dark Energy Spectroscopic Instrument (DESI) has found that the ΛCDM model does not fit as well as models in which dark energy is "evolving" over time, rather than remaining constant.

Both the Hubble tension and the surprises revealed by DESI are difficult to resolve in models which use a simplified 100-year-old cosmic expansion law—Friedmann's equation.

This assumes that, on average, the universe expands uniformly—as if all cosmic structures could be put through a blender to make a featureless soup, with no complicating structure. However, the present universe actually contains a complex cosmic web of galaxy clusters in sheets and filaments that surround and thread vast empty voids.

Part 2