WHO agency says talc is 'probably' cancer-causing

The World Health Organization's cancer agency on Friday classified talc as "probably carcinogenic" for humans, however an outside expert warned against misinterpreting the announcement as a "smoking gun".

The decision was based on "limited evidence" that talc could cause ovarian cancer in humans, "sufficient evidence" it was linked to cancer in rats and "strong mechanistic evidence" that it shows carcinogenic signs in human cells, the WHO's International Agency for Research on Cancer (IARC) said.

Talc is a naturally occurring mineral which is mined in many parts of the world and is often used to make talcum baby powder.

Most people are exposed to talc in the form of baby powder or cosmetics, according to the Lyon-based IARC.

But the most significant exposure to talc occurs when talc is being mined, processed or used to make products, it added.

The agency said there were numerous studies which consistently showed an increase in the rate of ovarian cancer in women who use talc on their genitals.

But it could not rule out that the talc in some studies was contaminated with cancer-causing asbestos.

"A causal role for talc could not be fully established," according the agency's findings published in The Lancet Oncology.

 Leslie T Stayner et al, Carcinogenicity of talc and acrylonitrile, The Lancet Oncology (2024). DOI: 10.1016/S1470-2045(24)00384-X

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True scale of carbon impact from long-distance travel revealed

The reality of the climate impact of long-distance passenger travel has been revealed in new research.

Despite only accounting for less than 3% of all trips by UK residents, journeys of more than 50 miles (one way) are responsible for 70% of all passenger travel-related carbon emissions.

The disparity is even greater when international travel is singled out: International journeys are only 0.4% of total trips, but are responsible for 55% of emissions.

The new research, published recently in the journal Nature Energy, also shows that targeting long-distance travel may be a more effective way of tackling emissions than current efforts focusing on local and commuter journeys.

While the number of long and short distance domestic journeys by car has fallen slightly over the last 25 years, international air travel has increased significantly, driven by an increase in trips for leisure and visiting friends and family.

The scale of the impact of long-distance travel is very large indeed. That just less than 3% of our trips are responsible for around 60% of miles and 70% of emissions shows how important long-distance travel is in the fight to combat climate change. Worryingly, long-distance trips, especially flights, have been growing; however, they offer opportunities too.

Using a new metric they have created, called emission reduction sensitivity, the research team has calculated which types of travel could be changed to maximize a reduction in carbon emissions from passenger travel while affecting as few people or trips as possible.

Part 1

The research found that if all car journeys under eight miles were shifted to walking or cycling, there would be a 9.3% reduction in carbon emissions. However, around 55% of all journeys would need to be shifted to achieve this, as most travel is done locally and in cars.

Calculated by dividing the carbon reduction percentage by the percentage of journeys altered, the emission reduction sensitivity for this change would be just 0.17—the lowest recorded in the study.

By contrast, if all flights of less than 1,000 miles were moved to rail, there would be a 5.6% reduction in emissions but only 0.17% of journeys would be affected—resulting in a sensitivity value of 33.2.

At the top end, theoretically limiting everyone who flies now to one return flight abroad per year would have a value of 158.3, as so few journeys would be affected.

The researchers stress that the potential changes are only suggestions meant to make us realize and reassess the impact of our long-distance travel, rather than concrete policy proposals.

While efforts to move local journeys to more sustainable modes of transport are really positive, by omitting aviation emissions from national statistics—as is the case at the moment in nearly all countries—we are not getting a holistic picture and ignoring a large part of the problem.

A call to rethink our travel's carbon impact

The researchers also hope that their findings can act as a driver for policymakers to look at changes in how effort is assigned when dealing with the impact of travel on the environment.

The research also offers the public an insight into the impact that changing their behavior could have.

The important thing both at the policy and personal level is that we prioritize the relatively fewer longer distance trips—especially flights—in order to realize the largest reductions.

Casting a long shadow: the role of long distance travel in carbon emissions from and decarbonisation of passenger travel, Nature Energy (2024). DOI: 10.1038/s41560-024-01561-3 , www.nature.com/articles/s41560-024-01561-3

Part 2

The evidence is mounting: Humans were responsible for the extinction of large mammals

The debate has raged for decades: Was it humans or climate change that led to the extinction of many species of large mammals, birds, and reptiles that have disappeared from Earth over the past 50,000 years?

By "large," we mean animals that weighed at least 45 kilograms—known as megafauna. At least 161 species of mammals were driven to extinction during this period. This number is based on the remains found so far.

The largest of them were hit the hardest—land-dwelling herbivores weighing over a ton, the megaherbivores. Fifty thousand years ago, there were 57 species of megaherbivores. Today, only 11 remain. These remaining 11 species have also seen drastic declines in their populations, but not to the point of complete extinction.

A research group  now concludes that many of these vanished species were hunted to extinction by humans.

They present this conclusion in a review article invited by and published in the journal Cambridge Prisms: Extinction. A review article synthesizes and analyses existing research within a particular field.

The researchers incorporated several research fields, including studies directly related to the extinction of large animals, such as:

• The timing of species extinctions
• The animals' dietary preferences
• Climate and habitat requirements
• Genetic estimates of past population sizes
• Evidence of human hunting

Additionally, they included a wide range of studies from other fields necessary to understand the phenomenon, such as:

• Climate history over the past 1–3 million years
• Vegetation history over the past 1–3 million years
• Evolution and dynamics of fauna over the past 66 million years
• Archaeological data on human expansion and lifestyle, including dietary preferences

Part 1

The dramatic climate changes during the last interglacial and glacial periods (known as the late Pleistocene, from 130,000 to 11,000 years ago) certainly affected populations and distributions of both large and small animals and plants worldwide. However, significant extinctions were observed only among the large animals, particularly the largest ones.

An important observation is that the previous, equally dramatic ice ages and interglacials over the past couple of million years did not cause a selective loss of megafauna. Especially at the beginning of the glacial periods, the new cold and dry conditions caused large-scale extinctions in some regions, such as trees in Europe. However, there were no selective extinctions of large animals.

The large and very selective loss of megafauna over the last 50,000 years is unique over the past 66 million years. Previous periods of climate change did not lead to large, selective extinctions, which argues against a major role for climate in the megafauna extinctions.
Another significant pattern that argues against a role for climate is that the recent megafauna extinctions hit just as hard in climatically stable areas as in unstable areas.
Archaeologists have found traps designed for very large animals, and isotope analyses of ancient human bones and protein residues from spear points show that they hunted and ate the largest mammals.
Early modern humans were effective hunters of even the largest animal species and clearly had the ability to reduce the populations of large animals. These large animals were and are particularly vulnerable to overexploitation because they have long gestation periods, produce very few offspring at a time, and take many years to reach sexual maturity.
The analysis shows that human hunting of large animals such as mammoths, mastodons, and giant sloths was widespread and consistent across the world.

It also shows that the species went extinct at very different times and at different rates around the world. In some local areas, it happened quite quickly, while in other places it took over 10,000 years. But everywhere, it occurred after modern humans arrived, or in Africa's case, after cultural advancements among humans.
Part 2

Species went extinct on all continents except Antarctica and in all types of ecosystems, from tropical forests and savannas to Mediterranean and temperate forests and steppes to arctic ecosystems.
Many of the extinct species could thrive in various types of environments. Therefore, their extinction cannot be explained by climate changes causing the disappearance of a specific ecosystem type, such as the mammoth steppe—which also housed only a few megafauna species.
Most of the species existed under temperate to tropical conditions and should actually have benefited from the warming at the end of the last ice age.
The researchers point out that the loss of megafauna has had profound ecological consequences. Large animals play a central role in ecosystems by influencing vegetation structure (e.g., the balance between dense forests and open areas), seed dispersal, and nutrient cycling. Their disappearance has resulted in significant changes in ecosystem structures and functions.

Jens-Christian Svenning et al, The late-Quaternary megafauna extinctions: Patterns, causes, ecological consequences and implications for ecosystem management in the Anthropocene, Cambridge Prisms: Extinction (2024). DOI: 10.1017/ext.2024.4

The numbers of extinct and surviving species come from the freely accessible database PHYLACINE 1.2.1, which lists all known mammals that have lived in the past 129,000 years, including those that have gone extinct recently or are only found in captivity.

Part 3

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Incredible New Tech Lets Scientists Watch Fetuses Develop in Real Time

Bacterial glitter: New findings open up possibilities for sustainable color technologies

An international team of researchers  has investigated the mechanism that makes some types of bacteria reflect light without using pigments. The researchers were interested in the genes responsible and discovered important ecological connections. Their findings appear in the Proceedings of the National Academy of Sciences.

The iridescent colors known from peacock feathers or butterfly wings are created by tiny structures that reflect light in a special way. Some bacterial colonies form similar glittering structures.

The scientists sequenced the DNA of 87 structurally colored bacteria and 30 colorless strains and identified genes that are responsible for these fascinating colonies. These findings could lead to the development of environmentally-friendly dyes and materials.

Scientists  discovered that the genes responsible for structural color are mainly found in oceans, freshwater, and special habitats such as intertidal zones and deep-sea areas. In contrast, microbes in host-associated habitats such as the human microbiome displayed very limited structural colour. 

The study results indicate that the colorful bacterial colony structures are not only used to reflect light. Surprisingly, these genes are also found in bacteria that live in deep oceans without sunlight. This could imply that the colors could reflect deeper processes of cell organization with important functions, such as protecting the bacteria from viruses, or efficiently colonizing floating food particles. These findings could inspire new, sustainable technologies based on these natural structures.

Colin J. Ingham et al, Structural color in the bacterial domain: The ecogenomics of a 2-dimensional optical phenotype, Proceedings of the National Academy of Sciences (2024). DOI: 10.1073/pnas.2309757121

Researchers reveal a master controller of development and aging

Researchers have unlocked crucial molecular secrets of aging in cells, potentially paving the way to improve quality of life as people age.

The study, published in Cell Metabolism, decoded the process by which genes regulate how people mature as they grow and age.

By analyzing molecular datasets from both people and mice and then comparing different age groups over time, the researchers investigated the activity of genes involved in both developmental and aging processes.

Master controller genes regulate which genes are turned on or off in each of our cells, making sure that each cell does its specific job.

The scientists followed the activity of the master regulator Activator Protein 1 or AP-1 and found that it progressively activated adult genes, while the activity of 'early-life' genes involved in development were dialed down, and this process was shared across cell types.

The study found this process in our cells was predictable across the different life stages, as people mature.

It was ongoing in adulthood, likely because AP-1 is also activated by a number of stress and inflammatory processes as well as by a protein in our blood that increases with age. This further dampens genes most active early in life, which may drive many of the predictable changes of aging.

To address the diseases associated with aging, like Alzheimer's disease, metabolic liver disorders and stroke, researchers must first understand the process causing bodies to age.

By pinpointing AP-1 as a master controller linked to aging across cell types, scientists can now study the effects of drugs that reduce its activity to extend quality of life. The goal is to prevent diseases of aging from escalating or occurring in the first place by targeting the underlying aging process to allow people to grow older in better health.

 Ralph Patrick et al, The activity of early-life gene regulatory elements is hijacked in aging through pervasive AP-1-linked chromatin opening, Cell Metabolism (2024). DOI: 10.1016/j.cmet.2024.06.006

Boys born with higher natural resistance to HIV, study finds

Baby girls are more likely to acquire HIV from their mothers during pregnancy or childbirth than infant boys, who are conversely more likely to achieve cure or remission, researchers say in a new study that sheds light on the gender differences in immune systems.

An estimated 1.3 million women and girls living with HIV become pregnant each year and the rate of transmission to the child during pregnancy, labor, delivery or breastfeeding—in the absence of any intervention—ranges from 15 to 45%, according to the World Health Organization.

This new study identified some of the key mechanisms by which sustained HIV remission can be achieved—mechanisms that are relevant to children and adults alike.

Researchers  evaluated 284 infants in KwaZulu-Natal, South Africa, one of the world's highest HIV-prevalent areas, who were started at birth on a mix of HIV medicines known as combination anti-retroviral therapy (cART), after being exposed to HIV during pregnancy.

They found that HIV transmission to male fetuses was 50% less common than to females.

Affected males had lower levels of the virus in the blood and to date, in this study, four male infants have been identified who have achieved HIV cure/remission—i.e. maintained undetectable levels of HIV in the blood even without therapy.

HIV cure is categorized as "true cure" in which the virus has been eradicated totally from the body and "functional cure" or "cure/remission," in which the virus is no longer detectable in the blood even after treatment has been discontinued.

The researchers say the disparity found between male and female infants is likely due to the lower levels of activated CD4 T cells in male fetuses than in females, making it harder for the virus to establish a reservoir and providing a barrier against infection.

If by chance a virus gets transmitted to a male, it struggles to persist because there are not enough activated CD4 T cells available to sustain the infection.

CD4 T cells are a type of white blood cell that help the body fight infections such as HIV. They are an important part of the immune system and are targeted by HIV during infection. HIV spreads more slowly with lower CD4 T cell counts.

Nomonde Bengu et al, Sustained aviremia despite anti-retroviral therapy non-adherence in male children after in utero HIV transmission, Nature Medicine (2024). DOI: 10.1038/s41591-024-03105-4

Air pollution linked to a decrease in IVF birth rate success, new study shows

A pioneering study, presented at the ESHRE 40th Annual Meeting in Amsterdam, has revealed that exposure to fine particulate matter (PM) prior to the retrieval of oocytes (eggs) during in vitro fertilization (IVF) can reduce the odds of achieving a live birth by almost 40%.

The study analyzed PM10 exposure in the two weeks leading up to oocyte collection, finding that the odds of a live birth decreased by 38% (OR 0.62, 95% CI 0.43–0.89, p=0.010) when comparing the highest quartile of exposure (18.63 to 35.42 µg/m3) to the lowest quartile (7.08 to 12.92 µg/m3). The study abstract was published in Human Reproduction.

Conducted over an eight-year period in Perth, Australia, the research analyzed 3,659 frozen embryo transfers from 1,836 patients. The median female age was 34.5 years at the time of oocyte retrieval and 36.1 years at the time of frozen embryo transfer.

The study examined air pollutant concentrations over four exposure periods prior to oocyte retrieval (24 hours, two weeks, four weeks, and three months), with models created to account for co-exposures.

Increasing PM_2.5 exposure in the three months prior to oocyte retrieval was also associated with decreased odds of live birth, falling from 0.90 (95% CI 0.70–1.15) in the second quartile to 0.66 (95% CI 0.47–0.92) in the fourth quartile.

Importantly, the negative impact of air pollution was observed despite excellent overall air quality during the study period, with PM₁₀ and PM_2.5 levels exceeding WHO guidelines on just 0.4% and 4.5% of the study days, respectively.

 Leathersich S.J, et al, Particulate matter (PM2.5 and PM10) exposure prior to oocyte collection is associated with decreased live birth rates in subsequent frozen embryo transfers. Human Reproduction (2024).

Scientists create a cell that precludes malignant growth

Cell therapies could help in the treatment of hereditary diseases, myocardial infarction and hundreds of other diseases. For many blood diseases, new cells can already be transplanted into human patients, and diabetes has also been treated by transplanting cells obtained through organ donation or, more recently, β-cells modified from the patient's own stem cells.

A risk associated with gene-edited cells is unintentional DNA mutations, including those that predispose patients to cancer. Moreover, the difference in tissue types makes it impossible to transfer cells simply from one person to another.

Cells that suit anyone, or immunologically invisible cells, as it were, have been created, but they too are associated with an increased risk of cancer. Over a decade ago,  a research group set out to develop cells where these problems could be avoided. Now, the group has succeeded in producing cells which cannot proliferate unaided and which cannot therefore turn into malignant cells.

The study was published in Molecular Therapy.

Almost all of our diseases are fundamentally caused by cellular dysfunction. One medical dream is to fight tissue damage, diseases or even aging with new healthy cells. This new study takes us a step closer to safe and novel cell therapies.

The researchers modified stem cells to divide only if they are supplemented with thymidine, one of the building blocks of DNA. The cells that have been subjected to this safety treatment cannot replicate their genome without the supplementary component vital for DNA synthesis. This precludes their proliferation. When the cells are differentiated for their various tasks, they cease to divide and no longer require the supplement. The innovation has been protected by the University's Helsinki Innovation services (HIS).

Part 1

Initially, the researchers investigated whether cell growth can be regulated with an externally administered substance. Once successful, they examined whether the cells functioned normally.

They used stem cells to create insulin-producing β-cells that they then transplanted into laboratory animals. The cells regulated the blood glucose levels of the animals throughout the almost six-month experiment.
The cells are also able to differentiate into other tissue types as usual, and the researchers have not observed any differences in them other than their inability to proliferate without their say-so.
Stem cells are very primitive cells, as they have to be able to divide in abundance and develop in many different directions. They have potential for a range of purposes, but their primitive nature also poses a problem: What if some cells are not differentiated, but continue to grow in a primitive form? According to the scientists of the study, the research group's solution enables the efficient proliferation of cells during production, which can be halted at the desired time, such as following transplantation.
The solution also makes it possible to edit cells without fear of adverse effects of the editing itself. For example, cells can be made into something that the recipient's immune system does not recognize.
Previously, such cells would have been highly risky, as the immune system also monitors the onset of cancer. Now, that risk is very small or non-existent. Ideally, these cells could be turned into products suited to everyone and, when necessary, quickly deployed.

Rocio Sartori-Maldonado et al, Thymidylate synthase disruption to limit cell proliferation in cell therapies, Molecular Therapy (2024). DOI: 10.1016/j.ymthe.2024.06.014

Scientists successfully create a time crystal made of giant atoms

A crystal is an arrangement of atoms that repeats itself in space, in regular intervals: At every point, the crystal looks exactly the same. In 2012, Nobel Prize winner Frank Wilczek raised the question: Could there also be a time crystal—an object that repeats itself not in space but in time? And could it be possible that a periodic rhythm emerges, even though no specific rhythm is imposed on the system and the interaction between the particles is completely independent of time?

For years, Frank Wilczek's idea has caused much controversy. Some considered time crystals to be impossible in principle, while others tried to find loopholes and realize time crystals under certain special conditions.

Now, a particularly spectacular kind of time crystal has successfully been created at Tsinghua University in China, with the support from TU Wien in Austria. The team used laser light and special types of atoms, namely Rydberg atoms, with a diameter that is several hundred times larger than normal.  The results have been published in the journal Nature Physics.

The ticking of a clock is also an example of a temporally periodic movement. However, it does not happen by itself: Someone must have wound the clock and started it at a certain time. This starting time then determined the timing of the ticks. It is different with a time crystal:

According to Wilczek's idea, a periodicity should arise spontaneously, although there is actually no physical difference between different points in time.

The tick frequency is predetermined by the physical properties of the system, but the times at which the tick occurs are completely random; this is known as spontaneous symmetry breaking.

How this new work was done: 

Laser light was shone into a glass container filled with a gas of rubidium atoms. The strength of the light signal that arrived at the other end of the container was measured.

This is actually a static experiment in which no specific rhythm is imposed on the system. 

The interactions between light and atoms are always the same, the laser beam has a constant intensity. But surprisingly, it turned out that the intensity that arrives at the other end of the glass cell begins to oscillate in highly regular patterns.

The key to the experiment was to prepare the atoms in a special way: The electrons of an atom can orbit the nucleus on different paths, depending on how much energy they have. If energy is added to the outermost electron of an atom, its distance from the atomic nucleus can become very large.

Part1

In extreme cases, it can be several hundred times further away from the nucleus than usual. In this way, atoms with a giant electron shell are created—so-called Rydberg atoms.

If the atoms in their glass container are prepared in such Rydberg states and their diameter becomes huge, then the forces between these atoms also become very large.

And that in turn changes the way they interact with the laser. If you choose laser light in such a way that it can excite two different Rydberg states in each atom at the same time, then a feedback loop is generated that causes spontaneous oscillations between the two atomic states. This in turn also leads to oscillating light absorption. All by themselves, the giant atoms stumble into a regular beat, and this beat is translated into the rhythm of the light intensity that arrives at the end of the glass container.

So the researchers have created a new system here that provides a powerful platform for deepening their understanding of the time crystal phenomenon in a way that comes very close to Frank Wilczek's original idea.
Precise, self-sustained oscillations could be used for sensors.

Xiaoling Wu et al, Dissipative time crystal in a strongly interacting Rydberg gas, Nature Physics (2024). DOI: 10.1038/s41567-024-02542-9. On arXiv: arxiv.org/html/2305.20070v3

Part 2

New study sheds light on brain responses to emotionally-charged scenes

The ability to recognize and respond to emotionally-charged situations is essential to a species' evolutionary success. A new study published in Nature Communications advances our understanding of how the brain responds to emotionally charged objects and scenes.

This new  research reveals that the occipital temporal cortex is tuned not only to different categories of stimuli but it also breaks down these categories based on their emotional characteristics in a way that is well suited to guide selection between alternate behaviours.

The researchers analyzed the brain activity of a small group of volunteers viewing over 1,500 images depicting natural emotional scenes such as a couple hugging, an injured person in a hospital bed, a luxurious home, and an aggressive dog. Participants were asked to categorize the images as positive, negative or neutral and to also rate the emotional intensity of the images.

A second group of participants picked the behavioural responses that best matched each scene.

Using cutting-edge modeling of brain activity divided into tiny cubes (of under 3mm3), the study discovered that the occipital temporal cortex (OTC), a region at the back of the brain, is tuned to represent both the type of stimulus (single human, couple, crowd, reptile, mammal, food, object, building, landscape etc.) and the emotional characteristics of the stimulus—whether it's negative, positive or neutral and also whether it's high or low in emotional intensity. 

Machine learning showed that these stable tuning patterns were more efficient in predicting the behaviors matched to the images by the second group of participants than could be achieved by applying machine learning directly to image features—suggesting that the OTC efficiently extracts and represents the information needed to guide behaviour.

These findings expand our knowledge of how the human brain represents emotional natural stimuli.

Occipital-temporal cortical tuning to semantic and affective features of natural images predicts associated behavioral responses, Nature Communications (2024). DOI: 10.1038/s41467-024-49073-8

First local extinction due to sea level rise identified in the US

The United States has lost its only stand of the massive Key Largo tree cactus in what researchers think is the first local extinction of a species caused by sea level rise in the country.

The Key Largo tree cactus (Pilosocereus millspaughii) still grows on a few scattered islands in the Caribbean, including northern Cuba and parts of the Bahamas. In the United States, it was restricted to a single population in the Florida Keys, first discovered in 1992 and monitored intermittently since.

Salt water intrusion from rising seas, soil depletion from hurricanes and high tides, and herbivory by mammals had put significant pressure on the population. By 2021, what had been a thriving stand of about 150 stems was reduced to six ailing fragments, which researchers salvaged for off-site cultivation to ensure their survival.

"Unfortunately, the Key Largo tree cactus may be a bellwether for how other low-lying coastal plants will respond to climate change," say scientists. 

But don't worry, the researchers are studying and trying to rescue the remnants of a dwindling stock of this cactus. 

 First U.S. vascular plant extirpation linked to sea level rise? Pilosocereus millspaughii (Cactaceae) in the Florida Keys, U.S.A., Journal of the Botanical Research Institute of Texas (2024). DOI: 10.17348/jbrit.v18.i1.1350

'Unhealthy' gut microbiome patterns linked to heightened risk of death after organ transplant

'Unhealthy' gut microbiome patterns are linked to a heightened risk of death after a solid organ transplant, finds research published online in the journal Gut.

While these particular microbial patterns are associated with deaths from any cause, they are specifically associated with deaths from cancer and infection, regardless of the organ—kidney, liver, heart, or lung—transplanted, the findings show.

The make-up of the gut microbiome is associated with various diseases, including inflammatory bowel disease and diabetes. But few studies have had the data to analyze the association between the gut microbiome and long term survival, explain the researchers.

And while a shift away from a normal pattern of microbes to an 'unhealthy' pattern, known as gut dysbiosis, has been linked to a heightened risk of death generally, it's not clear whether this might also be associated with overall survival in specific diseases, they add.

To find out, they looked at the relationship between gut dysbiosis and death from all and specific causes in solid organ transplant recipients among whom the prevalence of gut dysbiosis is much higher than that of the general population. This makes them an ideal group to study the associations between gut dysbiosis and long term survival, say the researchers.

Part1

To find out, they looked at the relationship between gut dysbiosis and death from all and specific causes in solid organ transplant recipients among whom the prevalence of gut dysbiosis is much higher than that of the general population. This makes them an ideal group to study the associations between gut dysbiosis and long term survival, say the researchers.

They analyzed the microbiome profiles from 1,337 fecal samples provided by 766 kidney, 334 liver, 170 lung, and 67 heart transplant recipients and compared those with the gut microbiome profiles of 8,208 people living in the same geographical area of northern Netherlands.

The average age of the transplant recipients was 57, and over half were men (784; 59%). On average, they had received their transplant 7.5 years previously.

Part2

During a follow-up period of up to 6.5 years, 162 recipients died: 88 kidney, 33 liver, 35 lung and six heart recipients. Forty eight (28%) died from an infection, 38 (23%) from cardiovascular disease, 38 (23%) from cancer, and 40 (25%) from other causes.

The researchers looked at several indicators of gut dysbiosis in these samples: microbial diversity; how much their gut microbiomes differed from the average microbiome of the general population; the prevalence of antibiotic resistance genes; and virulence factors which help bacteria to invade cells and evade immune defenses.
The analysis revealed that the more the gut microbiome patterns of the transplant recipients diverged from those of the general population, the more likely they were to die sooner after their procedure, irrespective of the organ transplanted.

Similar associations emerged for the abundance of antibiotic resistance genes and virulence factors.

The researchers identified 23 bacterial species among all the transplant recipients that were associated with either a heightened or lower risk of death from all causes.
Part3

The researchers further analyzed all bacterial species simultaneously using AI. This revealed a second pattern of 19 different species that were also associated with an increased risk of death.

This is an observational study, and as such, no definitive conclusions can be drawn about the causal roles of particular bacteria.

But, conclude the researchers, "Our results support emerging evidence showing that gut dysbiosis is associated with long-term survival, indicating that gut microbiome targeting therapies might improve patient outcomes, although causal links should be identified first."

 Casper Swarte et al, Multiple indicators of gut dysbiosis predict all-cause and cause-specific mortality in solid organ transplant recipients, Gut (2024). DOI: 10.1136/gutjnl-2023-331441

Part4

Hepatitis C leaves 'scars' in immune cells even after successful treatment

Chronic hepatitis C, caused by the hepatitis C virus, can lead to severe complications such as liver cirrhosis and liver cancer. The advent of highly effective direct-acting antivirals (DAAs) has resulted in high cure rates for this chronic viral infection. However, it has been reported that the immune system of patients does not fully recover even after being cured.

This work provided new insights into the lasting effects of chronic hepatitis C virus (HCV) infection on the immune system, even after the disease has been successfully treated.

The research team has discovered that traces of "epigenetic scars" remain in regulatory T cells and exhibit sustained inflammatory properties long after the virus is cleared from the body. The paper is published in the Journal of Hepatology.

So-Young Kim et al, Epigenetic scars in regulatory T cells are retained after successful treatment of chronic hepatitis C with direct-acting antivirals, Journal of Hepatology (2024). DOI: 10.1016/j.jhep.2024.06.011

How lasers and 2D materials could solve the world's plastic problem

A global research team has developed a way to blast the molecules in plastics and other materials with a laser to break them down into their smallest parts for future reuse.

The discovery, which involves laying these materials on top of two-dimensional materials called transition metal dichalcogenides and then lighting them up, has the potential to improve how we dispose of plastics that are nearly impossible to break down with today's technologies.

By harnessing these unique reactions, we can explore new pathways for transforming environmental pollutants into valuable, reusable chemicals, contributing to the development of a more sustainable and circular economy.

This discovery has significant implications for addressing environmental challenges and advancing the field of green chemistry.

Jingang Li et al, Light-driven C–H activation mediated by 2D transition metal dichalcogenides, Nature Communications (2024). DOI: 10.1038/s41467-024-49783-z

No GPS, no problem: Researchers are making quantum sensing tools more compact and accurate to replace GPS

Fundamental physics—let alone quantum physics—might sound complicated to many, but it can actually be applied to solve everyday problems.

Imagine navigating to an unfamiliar place. Most people would suggest using GPS, but what if you were stuck in an underground tunnel where radio signals from satellites were not able to penetrate? That's where quantum sensing tools come in.

Researchers  are working at making sensing instruments like atomic accelerometers smaller and more accurate so they can be used to navigate when GPS is down.

Atoms are excellent at making accurate measurements because they are all the same. Atomic measurements made in one laboratory would be indistinguishable from those made in another laboratory, as the atoms behave in precisely the same way.

One example of how this physics concept can be applied is making a highly accurate navigation system with these atoms.

As atoms have mass, they can be used to measure accelerations, helping us build atom-based sensors like atomic accelerometers.

The accelerometers let you know how fast and far you're moving in a given direction. They can be coupled with gyroscopes, which tell you whether you've changed directions and how far you've turned, to make a complete measurement. These navigation instruments are useful when you don't have access to GPS. 

One of the challenges they're facing is how they can engineer this in a thoughtful way.

For example, they have to think very carefully about how they can miniaturize atomic accelerometers. These accelerometers have historically operated in big laboratory scale systems, where equipment is heavy and consumes a lot of power. To make the accelerometers suitable for public use, Researchers are investigating how to retain their high precision in a much more compact, power-efficient and attractive medium.

Not only do quantum sensing devices work in areas that don't have access to GPS, they can also be part of an exciting new avenue: national security applications.

Part 1

Modern conflicts are becoming increasingly electronic and less kinetic, as nations vie for information superiority. The radio signal from GPS satellites is easy to disrupt and jam because it is far away. Thus, in any modern conflict, both sides will attempt to deny each other access to these radio signals.
More traditional navigation instruments like inertial systems are un-jammable, as they work by adding up accelerations and rotations to measure our change in position. So they can replace GPS in times of conflict. However, all the errors made also get added up, so researchers are interested in using an atom-based measurement to ensure it is more accurate.
Atomic accelerometers are one example of these inertial systems. These systems are present in sensors on aircraft and ships, guiding their movement through airspaces and waters. However, existing mechanical-based sensors can wear out easily due to friction, leading to them being swapped out every year and costing a lot of money. They are also hard to build because they're small and delicate.
The quantum approach based on atoms pursued by the present researchers could provide acceleration measurements with no moving parts.

For example, if submarines want to be stealthy and quiet in defense scenarios, keeping track of what it's doing and how it's moved through inertial systems is pretty much the only game in town.
Achieving this fine balance between simplicity and accuracy is the researchers' main goal, and they hope that their efforts will translate to real-world prototypes someday.
Source: USC

Part 2

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Familial endocrine diseases linked to increased risk of pregnancy loss, new research shows

Women who have close family members with endocrine diseases--including type 2 diabetes, thyroid diseases and polycystic ovary syndrome (PCOS)--are at higher risk of pregnancy loss, a new study has found.

The research, presented recently at the ESHRE 40th Annual Meeting in Amsterdam, examined the association between various endocrine diseases and the incidence of pregnancy loss.

The study investigated 366,539 women in Denmark between 1973 and 2022. The study found that women with parents diagnosed with endocrine diseases faced a 6% higher risk of pregnancy loss compared to those without a family history of endocrine diseases.

Similarly, if a woman's sister had an endocrine disease, her risk of experiencing pregnancy loss increased by 7%. These patterns persisted even when individual cases of the diseases were considered.

The results highlight having a family history of endocrine disease as an important yet previously underexplored factor in assessing the risk of pregnancy loss.

Egerup, P., et al, Familial endocrine disease increases the risk of pregnancy loss and recurrent pregnancy loss– a nationwide register-based study of 366,548 Danish women. Human Reproduction (2024). academic.oup.com/humrep/issue/39/Supplement_1

Auroras caused by head-on blows to Earth's magnetic field could damage critical infrastructure, scientists say

Auroras are beautiful colourful lights that catch our imagination. Poets write poems, artists, including me, create art works based on them,  writers weave stories around them.

They have inspired myths and portents for millennia—but only now, with modern technology dependent on electricity, are we appreciating their true power.

The same forces which cause auroras also cause currents that can damage infrastructure which conducts electricity, like pipelines.

Now scientists writing in Frontiers in Astronomy and Space Sciences have demonstrated that the impact angle of interplanetary shocks is key to the currents' strength, offering an opportunity to forecast dangerous shocks and shield critical infrastructure.

Auroras and geomagnetically induced currents are caused by similar space weather drivers. 

The aurora is a visual warning that indicates that electric currents in space can generate these geomagnetically-induced currents on the ground.

The auroral region can greatly expand during severe geomagnetic storms. Usually, its southernmost boundary is around latitudes of 70 degrees, but during extreme events it can go down to 40 degrees or even further, which certainly occurred during the May 2024 storm—the most severe storm in the past two decades.

Auroras are caused by two processes: either particles ejected from the sun reach Earth's magnetic field and cause a geomagnetic storm, or interplanetary shocks compress Earth's magnetic field.

These shocks also generate geomagnetically induced currents, which can damage infrastructure that conducts electricity. More powerful interplanetary shocks mean more powerful currents and auroras—but frequent, less powerful shocks could also do damage.

The most intense deleterious effects on power infrastructure occurred in March 1989 following a severe geomagnetic storm—the Hydro-Quebec system in Canada was shut down for nearly nine hours, leaving millions of people with no electricity.

But weaker, more frequent events such as interplanetary shocks can pose threats to ground conductors over time.  Recent research work shows that considerable geoelectric currents occur quite frequently after shocks, and they deserve attention.

Part 1

Shocks which hit the Earth head-on, rather than at an angle, are thought to induce stronger geomagnetically induced currents, because they compress the magnetic field more. The scientists investigated how geomagnetically induced currents are affected by shocks at different angles and times of day.

Scientists found that more frontal shocks cause higher peaks in geomagnetically induced currents both immediately after the shock and during the following substorm. Particularly intense peaks took place around magnetic midnight, when the north pole would have been between the sun and Mäntsälä. Localized substorms at this time also cause striking auroral brightening.

Moderate currents occur shortly after the perturbation impact when Mäntsälä is around dusk local time, whereas more intense currents occur around midnight local time. 

Because the angles of these shocks can be predicted up to two hours before impact, this information could allow us to set in place protections for electricity grids and other vulnerable infrastructure before the strongest and most head-on shocks strike.

One thing power infrastructure operators could do to safeguard their equipment is to manage a few specific electric circuits when a shock alert is issued. This would prevent geomagnetically induced currents reducing the lifetime of the equipment.

However, the scientists didn't find strong correlations between the angle of a shock and the time it takes for it to hit and then induce a current. This may be because more recordings of currents at different latitudes are needed to investigate this aspect. Current data was collected only at a particular location, namely the Mäntsälä natural gas pipeline system.

Although Mäntsälä is at a critical location, it does not provide a worldwide picture.

First direct observations of interplanetary shock impact angle effects on actual geomagnetically induced currents: The case of the Finnish natural gas pipeline system, Frontiers in Astronomy and Space Sciences (2024). DOI: 10.3389/fspas.2024.1392697

Part 2

Researchers discover a new defense mechanism in bacteria

When confronted with an antibiotic, toxic substance, or other source of considerable stress, bacteria are able to activate a defense mechanism using cell-to-cell communication to "warn" unaffected bacteria, which can then anticipate, shield themselves and spread the warning signal.

This mechanism has just been described for the first time by a team of scientists .

It paves the way for the development of new, more effective antibiotic treatments that can target this bacterial communication system. The work appears in Nature Communications.

When they perceive a source of stress, bacteria spring into action, inducing changes in the expression of certain genes and their physiological properties to make them less vulnerable to the detected lethal substance. They also produce small alarmone proteins on their surface in order to contact and activate random neighboring bacteria.

Unstressed bacteria can only change state in the presence of a sufficient amount of alarmones. Thus, only a source of stress perceived by sufficient bacteria can trigger propagation of this activation.

The mechanism offers several advantages: It limits the unnecessary use of energy and enables a rapid and coordinated response in the population. Because activation is gradual, it creates diversity in the population over time, thus increasing the bacteria's chances of survival.

These findings were established using a dozen different families of antibiotics on populations of Streptococcus pneumoniae, the bacteria that causes pneumococcal infections.

 Pneumococcal competence is a populational health sensor driving multilevel heterogeneity in response to antibiotics, Nature Communications (2024). DOI: 10.1038/s41467-024-49853-2

The changing fire science

A new paper on the many ways wildfires affect people and the planet makes clear that as fires become more intense and frequent, the urgency for effective and proactive fire science grows. By addressing these challenges, the fire research community aims to better protect our planet and its inhabitants.

The paper appears in the Zenodo research repository.

Fire is a natural part of life on Earth, sustaining healthy and balanced ecosystems worldwide. But human activity and a changing climate are rapidly shifting both the frequency and severity of wildfire events, creating new risks to human and environmental health.

Recently, a group of scientists from 14 countries and across several disciplines—physical and social sciences, mathematics, statistics, remote sensing, fire communication and art, operational fire science, and fire management—gathered to discuss rapid changes in fire regimes and identify pathways to address these challenges.

The experts identified three grand challenges for fire science in the coming decades: understanding the role of fire in the carbon cycle, fire and extreme events, and the role of humans in fire.

If we want to improve the assessment of future fire impacts on people and the planet, we need to start with a better understanding of how climate, land cover changes, and human land management practices drive fire distribution and severity in the coming decades, the scientists say.

To address the grand challenges, the scientists identified three pressing research priorities: understanding the net carbon balance of fire, developing rapid response tools for wildfire events, and understanding fire's impact on society, especially marginalized and underrepresented populations.

A main goal of the white paper is to be able to improve fire modeling, predictability, and mitigation on both regional and global scales.

As fire events become more intense and frequent, the urgency for effective and proactive fire science grows. Scientists are taking steps  to address these challenges collectively, as a unified fire research community, to better protect our planet and its inhabitants.

Douglas S Hamilton et al, Igniting Progress: Outcomes from the FLARE workshop and three challenges for the future of transdisciplinary fire science, Zenodo (2024). DOI: 10.5281/zenodo.12634067

Subsurface of fingernails found to have precise tactile localization

Researchers found that humans have a surprisingly precise degree of tactile localization beneath their fingernails. In his study, published in the Proceedings of the Royal Society B, they tested how well volunteers could pinpoint the part of their fingernail being stimulated and outlines possible reasons.

Humans, like other primates, have nails on the ends of their fingers rather than claws—an evolutionary development that has not been explained. In this new effort, researchers investigated the sensitivity of the skin below the fingernails to learn more about how they were used by our ancestors.

The human fingernail does not have any nerves; thus, it cannot sense touch, pressure, heat, cold or other environmental characteristics. But there is skin beneath the fingernail that is capable of sensations, as evidenced by people who accidentally hit their thumb with a hammer or lose a nail.

To learn more about the sensitivity of the subsurface of the fingernail, the researchers recruited 38 adult volunteers. Each agreed to have their fingernails poked while they indicated on a photograph of a fingernail where they thought their fingernail was being touched. In the experiments, half of the volunteers had their nails touched by a stick, the other half by a filament. Only the thumb and middle finger were tested.

The study found that humans have highly precise localization in their nails—they can tell clearly which part of their nail is being touched. He suggests that this is due to mechanoreceptors called Pacinian corpuscles, buried in the skin beneath the nails. He notes that it is the same mechanism that allows blind people to localize touch using a cane. Pacinian corpuscles are able to detect small amounts of vibration, which happens when a slight impact occurs between a foreign object and a fingernail.

Why did humans develop fingernails instead of claws?  Why the skin beneath the nails is so sensitive? Researchers theorize that they likely served a sensorimotor function, giving humans more information about whatever their hands encounter.

Matthew R. Longo, Precise tactile localization on the human fingernail, Proceedings of the Royal Society B: Biological Sciences (2024). DOI: 10.1098/rspb.2024.1200

The geometry of life: Physicists determine what controls biofilm growth

This is physics helping biology.

From plaque sticking to teeth to scum on a pond, biofilms can be found nearly everywhere. These colonies of bacteria grow on implanted medical devices, our skin, contact lenses, and in our guts and lungs. They can be found in sewers and drainage systems, on the surface of plants, and even in the ocean.

Some research says that 80% of infections in human bodies can be attributed to the bacteria growing in biofilms.

The paper, "The biophysical basis of bacterial colony growth," was published in Nature Physics this week, and it shows that the fitness of a  biofilm- its ability to grow, expand, and absorb nutrients from the medium or the substrate—is largely impacted by the contact angle that the biofilm's edge makes with the substrate. The study also found that this geometry has a bigger influence on fitness than anything else, including the rate at which the cells can reproduce.

Understanding how biofilms grow—and what factors contribute to their growth rate—could lead to critical insights on controlling them, with applications for human health, like slowing the spread of infection or creating cleaner surfaces.

 Aawaz R. Pokhrel et al, The biophysical basis of bacterial colony growth, Nature Physics (2024). DOI: 10.1038/s41567-024-02572-3

Air pollution may affect lupus risk

New research published in Arthritis & Rheumatology indicates that chronic exposure to air pollutants may increase the risk of developing lupus, an autoimmune disease that affects multiple organs.

For the study, investigators analyzed data on 459,815 participants from the UK Biobank. A total of 399 lupus cases were identified during a median follow-up of 11.77 years. Air pollutant exposure was linked with a greater likelihood of developing lupus. Individuals with a high genetic risk and high air pollution exposure had the highest risk of developing lupus compared with those with low genetic risk and low air pollution exposure.

This study provides crucial insights into the air pollution contributing to autoimmune diseases. The findings can inform the development of stricter air quality regulations to mitigate exposure to harmful pollutants, thereby reducing the risk of lupus.

Air pollution, genetic susceptibility and risk of incident Systemic lupus erythematosus: A prospective cohort study, Arthritis & Rheumatology (2024). DOI: 10.1002/art.42929

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Some environmental toxicants linked to depressive symptoms

Certain categories of environmental toxicants are associated with depressive symptoms, according to a study published online July 3 in JAMA Network Open.

Researchers  screened and assessed the associations between potential environmental toxicants and depressive symptoms among 3,427 participants from the 2013 to 2014 and 2015 to 2016 waves of the National Health and Nutrition Examination Survey. Exposures were assessed for 62 toxicants in 10 categories; the association with depression scores, measured by the 9-item Patient Health Questionnaire (PHQ-9), was examined.

The researchers identified associations between 27 chemical compounds or metals in six of 10 categories of environmental toxicants and the prevalence of depressive symptoms, including the volatile organic compound metabolites N-acetyl-S-(2 hydroxy-3-butenyl)-L-cysteine and total nicotine equivalent-2 (odds ratios, 1.74 and 1.42, respectively).

Compared with women and older individuals, men and younger individuals seemed more vulnerable to environmental toxicants. Overall, 5–19 percent of the associations were mediated by peripheral white blood cell count.

"This research highlights the significance of preventing and regulating important environmental toxicants to gain fresh insights into preventing and potentially treating depression," the authors write in their paper.

Jianhui Guo et al, Environmental Toxicant Exposure and Depressive Symptoms, JAMA Network Open (2024). DOI: 10.1001/jamanetworkopen.2024.20259

Respiratory bacteria 'turn off' immune system to survive, study finds

Researchers have identified how a common bacterium is able to manipulate the human immune system during respiratory infections and cause persistent illness. The research was published in PLOS Pathogens.

This study found the virulence mechanisms of Haemophilus influenzae, a bacterium that plays a significant role in worsening respiratory tract infections.

These bacteria are especially damaging to vulnerable groups, such as those with cystic fibrosis, asthma, the elderly, and Indigenous communities.

In some conditions, such as asthma and chronic obstructive pulmonary disease,

they can drastically worsen symptoms.

This research shows the bacterium persists by essentially turning off the body's immune responses, inducing a state of tolerance in human respiratory tissues.

Part 1

The researchers prepared human nasal tissue in the lab, growing it to resemble the surfaces of the human respiratory tract, then monitored gene expression changes over a 14-day 'infection.'
They found very limited production of inflammation molecules over time, which normally would be produced within hours of bacteria infecting human cells.

Researchers then applied both live and dead Haemophilus influenzae, showing the dead bacteria caused a fast production of the inflammation makers, while live bacteria prevented this.
This proved that the bacteria can actively reduce the human immune response.
If local immunity drops, for example during a viral infection, the bacteria may be able to 'take over' and cause a more severe infection.

 PLOS Pathogens (2024). journals.plos.org/plospathogen … journal.ppat.1012282

Part 2

Densely packed E. coli form an immobile material similar to colloidal glass, research shows

Dense E. coli bacteria have several similar qualities to colloidal glass, according to new research at the University of Tokyo. Colloids are substances made up of small particles suspended within a fluid, like ink for example. When these particles become higher in density and more packed together, they form a "glassy state."

When researchers multiplied E. coli bacteria within a confined area, they found that they exhibited similar characteristics. More surprisingly, they also showed some other unique properties not typically found in glass-state materials.

This study, which is published in PNAS Nexus, contributes to the understanding of glassy "active matter," a relatively new field of materials research which crosses physics and life science.

In the long term, the researchers hope that these results will contribute to developing materials with new functional capabilities, as well as aiding our understanding of biofilms (where microorganisms stick together to form layers on surfaces) and natural bacterial colonies.

Researchers have now found that the bacteria E. coli can behave in a similar way.

Since bacteria are very different from what we know of as glass, it was surprising that many of the statistical properties of glassy materials were the same for bacteria.

In this experiment, As the number of E. coli increased, they became caged in by their neighbors, restricting their ability to swim freely. Over time, they transitioned to a glassy state. This transition is similar to glass formation, as the researchers noted a rapid slowdown of movement, the caged-in effect and dynamic heterogeneity (whereby molecules travel longer distances in some areas but hardly move in others).

Part 1

What made this bacterial glass different to other glasslike substances was the spontaneous formation of "microdomains" and the collective motion of the bacteria within these areas. These occurred where groups of the rod-shaped E. coli became aligned the same way.

The researchers were also surprised that the way the bacteria vitrify (turn into a glasslike state) apparently violates a physical law of typical thermal systems. What we characteristically know as glass, including colloidal glass, is classed as thermal glass. However, recently researchers have started to explore glassy states, like the one reported in this paper, which aren't considered thermal glass but share many of the same properties.

"Collections of 'self-propelled particles' like we see here have recently been regarded as a new kind of material called active matter, which is currently a hot topic and shows great potential.

Hisay Lama et al, Emergence of bacterial glass, PNAS Nexus (2024). DOI: 10.1093/pnasnexus/pgae238

Part 2

How water controls the speed of muscle contraction

The flow of water within a muscle fiber may dictate how quickly muscle can contract, according to a new study.

Nearly all animals use muscle to move, and it's been known for a long time that muscle, like all other cells, is composed of about 70% water. But researchers don't know what sets the range and upper limits of muscle performance. Previous research into how muscle works focused only on how it worked on a molecular level rather than how muscle fibers are shaped, that they are three-dimensional and are full of fluid.

Researchers now created a theoretical model of water's role in muscle contraction and found that how fluid moves through a muscle fiber determines how quickly a muscle fiber can contract.

They also found that muscle exhibits a new kind of elasticity called odd elasticity that allows muscle to generate power using three dimensional deformations, shown in a common observation that when a muscle fiber contracts lengthwise, it also bulges perpendicularly. Their results are published in the journal Nature Physics.

These results suggest that even such basic questions as how quickly muscle can contract or how many ways muscle can generate power have new and unexpected answers when one takes a more integrated and holistic view of muscle as a complex and hierarchically organized material rather than just a bag of molecules.

Part 1

Muscle fibers are composed of many components, such as various proteins, cell nuclei, organelles such as mitochondria, and molecular motors such as myosin that convert chemical fuel into motion and drive muscle contraction.
All of these components form a porous network that is bathed in water. So an appropriate, coarse-grained description for muscle is that of an active sponge, say the researchers.
But the squeezing process takes time to move water around, so the researchers suspected that this movement of water through the muscle fiber set an upper limit on how rapidly a muscle fiber can twitch.

To test their theory, they modeled muscle movements in multiple organisms across mammals, insects, birds, fish and reptiles, focusing on animals that use muscles for very fast motions. They found that muscles that produce sound, such as the rattle in a rattlesnake's tail, that can contract ten to hundreds of times per second typically don't rely on fluid flows. Instead, these contractions are controlled by the nervous system and are more strongly dictated by molecular properties, or the time it takes for molecular motors within cells to bind and generate forces.
But in smaller organisms, such as flying insects who are beating their wings a few hundred to a thousand times per second, these contractions are too fast for neurons to directly control. Here fluid flows are more important.
In these cases, the researchers found that fluid flows within the muscle fiber are important and their mechanism of active hydraulics is likely to limit the fastest rates of contraction.
The researchers also found that when muscle fibers act as an active sponge, the process also causes the muscles to act as an active elastic engine. When something is elastic, such as a rubber band, it stores energy as it tries to resist deformation. Imagine holding a rubber band between two fingers and pulling it back.

When you release the rubber band, the band also releases the energy stored when it was being stretched. In this case, energy is conserved—a basic law of physics that dictates that the amount of energy within a closed system should remain the same over time.
But when muscle converts chemical fuel into mechanical work, it can produce energy like an engine, violating the law of the conservation of energy. In this case, muscle shows a new property called "odd elasticity," where its response when squashed in one direction versus another is not mutual.

Unlike the rubber band, when muscle contracts and relaxes along its length, it also bulges out perpendicularly, and its energy does not stay the same. This allows muscle fibers to generate power from repetitive deformations, behaving as a soft engine.

These results are in contrast to prevailing thought, which focuses on molecular details and neglects the fact that muscles are long and filamentous, are hydrated, and have processes on multiple scales.
All together, our results suggest a revised view of how muscle functions is essential to understand its physiology. This is also crucial to understanding the origins, extent and limits that underlie the diverse forms of animal movement.

Suraj Shankar et al, Active hydraulics and odd elasticity of muscle fibres, Nature Physics (2024). DOI: 10.1038/s41567-024-02540-x

Part 2

Monkey malaria is infecting people

Malaysia was on the brink of eliminating malaria – then a new parasite swung out of the jungle

A new malaria parasite comes from monkeys. With thousands already infected, experts fear it could one day spread between humans.

Malaria has been eliminated in Malaysia, but another variety is spilling out from the rainforest and infecting people: monkey malaria. Around 25,000 people have been infected with the Plasmodium knowlesi parasite since 2011, which causes nausea, fever and sometimes death. Deforestation has driven a spike in cases, pushing monkeys, mosquitoes and people into closer proximity. The disease isn’t limited to southeast Asia, and as it spreads so too does the chance that monkey malaria will adapt to be spread between humans.

https://www.telegraph.co.uk/global-health/science-and-disease/monke...

How galaxies avoid early death

Galaxies avoid an early death because they have a "heart and lungs" which effectively regulate their "breathing" and prevent them from growing out of control, a new study suggests.

If they didn't, the universe would have aged much faster than it has and all we would see today is huge "zombie" galaxies teeming with dead and dying stars.

That's according to a new study published in the Monthly Notices of the Royal Astronomical Society, which investigates one of the great mysteries of the universe—why galaxies are not as large as astronomers would expect.

Something appears to be stifling their enormous potential by limiting the amount of gas they absorb to convert into stars, meaning that instead of endlessly growing, something inside resists what was thought to be the inevitable pull of gravity.

Now, astrophysicists  think they may have uncovered the secret. They suggest that galaxies could in fact control the rate at which they grow through how they "breathe."

In their analogy, the researchers compared the supermassive black hole at the center of a galaxy to its heart, and the two bi-polar supersonic jets of gas and radiation they emit to airways feeding a pair of lungs.

Pulses from the black hole—or "heart"—can lead to jet shock fronts oscillating back and forth along both jet axes, much like the thoracic diaphragm in the human body moves up and down inside a chest cavity to inflate and deflate both lungs.

This can result in jet energy being transmitted widely into the surrounding medium, just as we breathe out warm air, resulting in slowing galaxy gas-accretion and growth.

The phenomenon is similar to the terrestrial equivalent of sound and shock waves being produced when opening a bottle of champagne, the screech of a car, rocket exhausts and the puncture of pressurized enclosures.

These supersonic jets might help in inhibiting galaxy growth.

The researchers concluded that a galaxy's lifespan can be extended with the help of its "heart and lungs," where the supermassive black hole engine at its core helps inhibit growth by limiting the amount of gas collapsing into stars from an early stage. This, the researchers say, has helped create the galaxies we see today.

Without such a mechanism, galaxies would have exhausted their fuel by now and fizzled out, as some do in the form of "red and dead" or "zombie" galaxies.

Carl Richards et al, Simulations of Pulsed Over-Pressure Jets: Formation of Bellows and Ripples in Galactic Environments, Monthly Notices of the Royal Astronomical Society (2024). DOI: 10.1093/mnras/stae1498

Scientists identify possible way to block muscle fatigue in long COVID, other diseases

Infections and neurodegenerative diseases cause inflammation in the brain. But for unknown reasons, patients with brain inflammation often develop muscle problems that seem to be independent of the central nervous system. Now, researchers  have revealed how brain inflammation releases a specific protein that travels from the brain to the muscles and causes a loss of muscle function.

The study, in fruit flies and mice, also identified ways to block this process, which could have implications for treating or preventing the muscle wasting sometimes associated with inflammatory diseases including bacterial infections, Alzheimer's disease and long COVID.

The study is published July 12 in the journal Science Immunology.

 The study suggests that when we get sick, messenger proteins from the brain travel through the bloodstream and reduce energy levels in skeletal muscle. This is more than a lack of motivation to move because we don't feel well. These processes reduce energy levels in skeletal muscle, decreasing the capacity to move and function normally.

To investigate the effects of brain inflammation on muscle function, the researchers modeled three different types of diseases—an E. coli bacterial infection, a SARS-CoV-2 viral infection and Alzheimer's.

When the brain is exposed to inflammatory proteins characteristic of these diseases, damaging chemicals called reactive oxygen species build up. The reactive oxygen species cause brain cells to produce an immune-related molecule called interleukin-6 (IL-6), which travels throughout the body via the bloodstream.

The researchers found that IL-6 in mice—and the corresponding protein in fruit flies—reduced energy production in muscles' mitochondria, the energy factories of cells.

Flies and mice that had COVID-associated proteins in the brain showed reduced motor function—the flies didn't climb as well as they should have, and the mice didn't run as well or as much as control mice.

The researchers saw similar effects on muscle function when the brain was exposed to bacterial-associated proteins and the Alzheimer's protein amyloid beta. They also saw evidence that this effect can become chronic. Even if an infection is cleared quickly, the reduced muscle performance remains many days longer in their experiments.

The bacterial brain infection meningitis is known to increase IL-6 levels and can be associated with muscle issues in some patients, for instance. Among COVID-19 patients, inflammatory SARS-CoV-2 proteins have been found in the brain during autopsy, and many long COVID patients report extreme fatigue and muscle weakness even long after the initial infection has cleared.

Patients with Alzheimer's disease also show increased levels of IL-6 in the blood as well as muscle weakness.

Part1

The study pinpoints potential targets for preventing or treating muscle weakness related to brain inflammation. The researchers found that IL-6 activates what is called the JAK-STAT pathway in muscle, and this is what causes the reduced energy production of mitochondria.
Several therapeutics already approved by the FDA for other diseases can block this pathway. JAK inhibitors as well as several monoclonal antibodies against IL-6 are approved to treat various types of arthritis and manage other inflammatory conditions.

The researchers are not sure why the brain produces a protein signal that is so damaging to muscle function across so many different disease categories, though.
They speculate about possible reasons this process has stayed with us over the course of human evolution, despite the damage it does, it could be a way for the brain to reallocate resources to itself as it fights off disease. More research is  needed  to better understand this process and its consequences throughout the body.

Shuo Yang et al, Infection and chronic disease activate a systemic brain-muscle signaling axis, Science Immunology (2024). DOI: 10.1126/sciimmunol.adm7908. www.science.org/doi/10.1126/sciimmunol.adm7908

Part 2

First fossil chromosomes discovered
Scientists have discovered intact chromosomes preserved in the skin of a woolly mammoth (Mammuthus primigenius) that met its end some 50,000 years ago — a feat previously thought to be impossible. The team also revealed the spatial organization of the mammoth’s DNA molecules and the active genes in its skin, including one responsible for giving the animal its fuzzy appearance. The study is the first to report the 3D structure of an ancient genome.

https://www.cell.com/cell/fulltext/S0092-8674(24)00642-1?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0092867424006421%3Fshowall%3Dtrue

Brain size riddle solved as humans exceed evolutionary trend

The largest animals do not have proportionally bigger brains—with humans bucking this trend—a study published in Nature Ecology & Evolution has revealed.

Researchers collected an enormous dataset of brain and body sizes from around 1,500 species to clarify centuries of controversy surrounding brain size evolution.

Bigger brains relative to body size are linked to intelligence, sociality, and behavioral complexity—with humans having evolved exceptionally large brains. The new research reveals the largest animals do not have proportionally bigger brains, challenging long-held beliefs about brain evolution.

For more than a century, scientists have assumed that this relationship was linear—meaning that brain size gets proportionally bigger, the larger an animal is. We now know this is not true. The relationship between brain and body size is a curve, essentially meaning very large animals have smaller brains than expected.

The research reveals a simple association between brain and body size across all mammals which allowed the researchers to identify the rule-breakers—species which challenge the norm.

Among these outliers includes our own species, Homo sapiens, which has evolved more than 20 times faster than all other mammal species, resulting in the massive brains that characterize humanity today. But humans are not the only species to buck this trend.

All groups of mammals demonstrated rapid bursts of change—both towards smaller and larger brain sizes. For example, bats very rapidly reduced their brain size when they first arose, but then showed very slow rates of change in relative brain size, suggesting there may be evolutionary constraints related to the demands of flight.

There are three groups of animals that showed the most pronounced rapid change in brain size: primates, rodents, and carnivores. In these three groups, there is a tendency for relative brain size to increase in time (the "Marsh-Lartet rule"*). This is not a trend universal across all mammals, as previously thought.

* a tendency for relative brain sizes to increase with time. But, as the study notes, this rule is not universally applicable across all mammals
part 1

These new results reveal a mystery. In the largest animals, there is something preventing brains from getting too big. Whether this is because big brains beyond a certain size are simply too costly to maintain remains to be seen. But as we also observe similar curvature in birds, the pattern seems to be a general phenomenon—what causes this 'curious ceiling' applies to animals with very different biology.

Chris Venditti et al, Co-evolutionary dynamics of mammalian brain and body size, Nature Ecology & Evolution (2024). DOI: 10.1038/s41559-024-02451-3

Part 2

New study finds 40% of cancer cases and almost half of all deaths  linked to modifiable risk factors

A study led by researchers at the American Cancer Society (ACS) finds four in 10 cancer cases and about one-half of all cancer deaths in adults 30 years old and older could be attributed to modifiable risk factors, including cigarette smoking, excess body weight, alcohol consumption, physical inactivity, diet, and infections.

Cigarette smoking was by far the leading risk factor, contributing to nearly 20% of all cancer cases and 30% of all cancer deaths. The findings are published in the journal CA: A Cancer Journal for Clinicians.

The risk factors included cigarette smoking (current and former smoking); secondhand smoke; excess body weight; alcohol consumption; consumption of red and processed meat; low consumption of fruits and vegetables, dietary fiber, and dietary calcium; physical inactivity; ultraviolet (UV) radiation; and infection with Epstein-Barr virus (EBV), Helicobacter pylori, hepatitis B virus (HBV), hepatitis C virus (HCV), human herpes virus-8 (HHV-8; also called Kaposi sarcoma herpesvirus), human immunodeficiency virus (HIV), and human papillomavirus (HPV). 

CA: A Cancer Journal for Clinicians (2024)

Introducing co-cultures: When co-habiting animal species share culture

Cooperative hunting, resource sharing, and using the same signals to communicate the same information—these are all examples of cultural sharing that have been observed between distinct animal species. In an opinion piece published June 19 in the journal Trends in Ecology & Evolution, researchers introduce the term "co-culture" to describe cultural sharing between animal species. These relationships are mutual and go beyond one species watching and mimicking another species' behavior—in co-cultures, both species influence each other in substantial ways.

Co-culture challenges the notion of species-specific culture, underscoring the complexity and interconnectedness of human and animal societies, and between animal societies," write the authors.

These cross-species interactions result in behavioral adaptations and preferences that are not just incidental but represent a form of convergent evolution.

Co-cultures have been observed between humans and nonhuman animals—for example, between humans and honeyguides in Tanzania and Mozambique, where the birds lead humans to honeybee nests. They are also evident between different species of nonhuman animals—for example, cooperative scavenging between ravens and wolves, cooperative hunting between false killer whales and bottlenose dolphins, and signal sharing between distinct species of tamarin. Ultimately, this inter-species sharing of culture could drive evolution, the researchers say.

"Cultural behaviors that enhance survival or reproductive success in a particular setting can lead to changes in population habits that, over time, could drive genetic selection," they write.

To extend our understanding of co-cultures, the researchers say that future studies could start by investigating wild animals in urban environments.

Part 1