Nobel Prize in chemistry for work on quantum dots, used in electronics and medical imaging

Three scientists won the Nobel Prize in chemistry Wednesday for their work on quantum dots—tiny particles just a few nanometers in diameter that can release very bright colored light and whose applications in everyday life include electronics and medical imaging.

Moungi Bawendi of MIT, Louis Brus of Columbia University, and Alexei Ekimov of Nanocrystals Technology Inc., were honored for their work with the tiny particles that "have unique properties and now spread their light from television screens and LED lamps," according to the Royal Swedish Academy of Sciences, which announced the award in Stockholm.

Quantum dots are tiny inorganic particles that glow a range of colors from red to blue when exposed to light. The color they emit depends upon the size of the particle.

Scientists can engineer the dots from materials that include gold to graphene to cadmium, and create their color by controlling their size. The tiniest particles, in which electrons are most tightly confined, emit blue light. Slightly larger particles, in which electrons bounce around a longer wavelength, emit red light.

What is anaphylaxis?

Maybe volcanoes doomed the dinosaurs

A machine-learning algorithm suggests that volcanic activity, rather than an asteroid,.... The algorithm simulated 300,000 scenarios of different amounts of volcanic gases until it found one that matched data from fossils. The gases would have started to cause dinosaur-dooming climate chaos long before the asteroid impact. “You can actually recreate the environmental conditions that could cause a dinosaur extinction solely by volcanism, as if the asteroid weren’t there,” says computational geologist and study co-author Alexander Cox. “But of course, we can't discount the fact that the asteroid definitely didn't cheer up the dinosaurs.”

https://www.science.org/doi/10.1126/science.adh3875

 How Amazonian forest degradation and monsoon circulation are interlinked

A pair of concerned researchers, has developed a computer model that shows linkages between forest degradation in the Amazon River basin and monsoon circulation.

That research suggested that if deforestation continues in the Amazon River basin, it could lead to a tipping point at which a certain degree of change can cause permanent changes to an ecosystem. In the case of the Amazon, the change would be from rainforest to a drier, savanna-like climate.

Over the course of many years, many studies have been conducted to understand how the characteristics of the Amazon River basin work together to maintain such a large rainforest. Such studies have shown that regional water cycling along with moisture exaltation from the plants, together with sunlight and even dust blown over from Africa, all contribute to the unique ecosystem, the largest rainforest in the world. Such work has also suggested that disruptions to parts of the system, such as cutting down trees, could result in major changes to the ecosystem. And if such changes were to occur, other studies have suggested the region would change from a rainforest to one that featured a vast savanna-like climate. Such a possible change is of major concern to climate scientists because the rainforest produces a lot of the Earth's oxygen. Additionally, destruction of the trees would result in the release of carbon they sequester, likely into the atmosphere, contributing further to climate change.

In this new effort, the researchers attempted to create a model that ties together degradation of the rainforest and monsoon circulation to show how and why a tipping point might be reached. To create their nonlinear dynamical model, the pair used data from other models that have been built over the past 40 years to simulate conditions in the rainforest. They also added weather data for the same period, including rainfall amounts, wind speeds and direction, and degree of evapotranspiration. They then modeled the rainforest in its original state to serve as a starting point. Next, they tweaked parameters to see the effects on the entire system. The model showed that cutting down trees at current rates in the Amazon region would indeed lead to a tipping point. They conclude that ecosystems with a feedback loop, such as the Amazon River basin, are particularly sensitive to change.

Nils Bochow et al, The South American monsoon approaches a critical transition in response to deforestation, Science Advances (2023). DOI: 10.1126/sciadv.add9973

New research may make future design of nanotechnology safer with fewer side effects

A new study, published in Nature Nanotechnology, may offer a strategy that mitigates negative side effects associated with intravenous injection of nanoparticles commonly used in medicine.

Nanotechnology's main advantage over conventional medical treatments is its ability to more precisely target tissues, such as cancer cells targeted by chemotherapy. However, when nanoparticles are injected, they can activate part of the immune system called complement. 

Complement is a group of proteins in the immune system that recognize and neutralize bacteria and viruses, including nanoparticles which are foreign to the body. As a result, nanoparticles are attacked by immune cells triggering side effects that include shortness of breath, elevated heart rate, fever, hypotension, and, in rare cases, anaphylactic shock.

The activation of the immune system after injection of nanoparticles can be challenging to understand and prevent. This new research is one step closer to providing a better understanding and a solution for people to receive the benefits of nanoparticles without side effects.

The researchers say while some progress has been made in mitigating adverse reactions through slow infusion and premedication with steroids and antihistamines, a significant number of people still experience reactions.

The goal is to prevent, avoid and mitigate adverse reactions and immune activation. 

Part 1

Specifically, this study focuses on an interesting group of complement inhibitors (called "regulators"). The research showed promising results.

Researchers  observed that the regulators being studied effectively inhibited complement activation by nanoparticles in human serum in vitro and animal models. Specifically, when injected at very low doses, the regulators completely and safely blocked activation of complement by nanoparticles in the animal models used. According to the authors, this is significant because when nanoparticles activate complement, the resulting immune response can not only cause an adverse reaction but it can also reduce the efficacy of nanomedicines.

This research also provides a better understanding of why and how complement regulators could help the body respond more favorably to nanoparticles. The study team observed that of the trillions of nanoparticles entering the blood in a standard injection, only a small fraction activated complement. Complement regulators worked as soon as nanoparticles started activating complement, thereby promptly mitigating immune activation.

These results suggest we have an exciting opportunity to explore how to further optimize the use of regulators with nanoparticles, with the goal of improving the efficacy and tolerability of multiple nanotechnology-based therapeutics and vaccines.

 The next step is to test the complement inhibitors with multiple nano particles and in difference disease models to fully understand the potential of this approach with the ultimate goal to apply the research in a clinical setting.

Inhibition of Acute Complement Responses Toward Bolus-Injected Nanoparticles by Targeted, Short-Circulating Regulatory Proteins, Nature Nanotechnology (2023). DOI: 10.1038/s41565-023-01514-z. www.nature.com/articles/s41565-023-01514-z

Part 2

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Iron atoms discovered on the move in Earth's solid inner core

The iron atoms that make up the Earth's solid inner core are tightly jammed together by astronomically high pressures—the highest on the planet.

But even here, there's space for wiggle room, researchers have found.

A study led by The University of Texas at Austin and collaborators in China found that certain groupings of iron atoms in the Earth's inner core are able to move about rapidly, changing their places in a split second while maintaining the underlying metallic structure of the iron—a type of movement known as "collective motion" that's akin to dinner guests changing seats at a table.

The results, which were informed by laboratory experiments and theoretical models, indicate that atoms in the inner core move around much more than previously thought.

The results could help explain numerous intriguing properties of the inner core that have long vexed scientists, as well as help shed light on the role the inner core plays in powering Earth's geodynamo—the elusive process that generates the planet's magnetic field.

Scientists think that iron atoms in the inner core are arranged in a repeating hexagonal configuration. According to Lin, most computer models portraying the lattice dynamics of iron in the inner core show only a small number of atoms—usually fewer than a hundred. But using an AI algorithm, the researchers were able to significantly beef up the atomic environment, creating a "supercell" of about 30,000 atoms to more reliably predict iron's properties.

At this supercell scale, the scientists observed groups of atoms moving about, changing places while still maintaining the overall hexagonal structure.

The researchers said that the atomic movement could explain why seismic measurements of the inner core show an environment that's much softer and malleable than would be expected at such pressures.

Youjun Zhang et al, Collective motion in hcp-Fe at Earth's inner core conditions, Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2309952120

Scientists discover arginine drives metabolic reprogramming to promote tumor growth in liver cancer

Cancer cells are chameleons. They completely change their metabolism to grow continuously. University of Basel scientists have discovered that high levels of the amino acid arginine drive metabolic reprogramming to promote tumor growth. This study suggests new avenues to improve liver cancer treatment.

The liver is a vital organ with many important functions in the body. It metabolizes nutrients, stores energy, regulates the blood sugar level, and plays a crucial role in detoxifying and removing harmful components and drugs. Liver cancer is one of the world's most lethal types of cancer. Conditions that cause liver cancer include obesity, excessive alcohol consumption and hepatitis C infection. Early diagnosis and appropriate therapeutic strategies are crucial for improving treatments in liver cancer.

In the past decade, scientists have made much progress in understanding the multiple facets of cancer. Historically, it has long been viewed as a disorder in cell proliferation. However, there is growing evidence that cancer is a metabolic disease. In other words, cancer arises when cells rewire their metabolism to allow uncontrolled cell proliferation. How do cells change their metabolism and how does this change in turn lead to tumorigenicity? With their new study in Cell, researchers have discovered a key driver of metabolic rewiring in liver cancer cells.

Healthy liver cells gradually change their behavior when turning into cancer cells. They reprogram their metabolism to grow as fast as possible, for example, they consume much more glucose than normal cells and they enhance the uptake of nutrients.

The most important thing they found is  elevated levels of arginine, although cancer cells produce less or none of this amino acid. The tumour cells accumulate high levels of arginine by increasing its uptake and suppressing its consumption.

Part 1

Furthermore, they found that the high levels of arginine are necessary for tumor development, independently of the amino acid's role in protein synthesis. This then begged the question: How does arginine lead to tumorigenicity?

At high concentrations, arginine binds to a specific factor, which triggers metabolic reprogramming and promotes tumour growth by regulating the expression of metabolic genes. As a consequence, tumour cells revert back to an undifferentiated embryonic cell state, in which they can divide indefinitely. Interestingly, tumour cells also benefit in another way from increasing the uptake of arginine.

Our immune cells depend on arginine to function properly. Therefore, depleting arginine in the tumour environment helps the tumour cells escape the immune system.

What do these findings mean for cancer therapy? The scientists propose to target the specific arginine-binding factor rather than depleting arginine.

Furthermore, metabolic changes such as increased arginine levels may serve as biomarkers for detecting cancer at an early stage, which is crucial for successful cancer treatment and patient survival.

 Arginine reprograms metabolism in liver cancer via RBM39, Cell (2023). DOI: 10.1016/j.cell.2023.09.011. www.cell.com/cell/fulltext/S0092-8674(23)01032-2

Part 2

How male mosquitoes compensate for having only one X chromosome

The research group has discovered the master regulator responsible for balancing the expression of X chromosome genes between males and females in the malaria mosquito.

This discovery helps scientists to better understand the evolution of the epigenetic mechanisms responsible for equalizing gene expression between the sexes. The findings may contribute to the development of new ways to prevent the spread of malaria. 

Just like humans, the sex of a mosquito is determined by the sex chromosomes: females have two X chromosomes (XX), while males have an X and a Y chromosome (XY). This can be problematic, as males have only half the number of X chromosome genes as females, and hence would have only half the amount of proteins from the X chromosome. To compensate for this, there must be a way to increase the expression of X chromosome genes in males.

The researchers discovered that the protein SOA (sex chromosome activation) is the key regulator that balances X chromosome gene expression in male mosquitoes. They found that SOA works by binding to X chromosome genes and increasing their expression, but only in males. Female mosquitoes, on the other hand, only produce a small amount of very short, non-functional SOA.

Balancing gene expression on sex chromosomes is essential for development in some species. However, others do not have such a mechanism at all. It is now discovered that in mosquitoes, balancing X chromosome expression by SOA is not necessary for development, but it does give males a head start.

This is an important clue as to how the mechanisms that balance gene expression on sex chromosomes may have evolved in the first place.

Agata Izabela Kalita et al, The sex-specific factor SOA controls dosage compensation in Anopheles mosquitos, Nature (2023). DOI: 10.1038/s41586-023-06641-0

How do our brains tell us when something goes wrong?

Whether improperly closing a door or shanking a kick in soccer, our brains tell us when we've made a mistake because these sounds differ from what we expect to hear. While it's long been established that our neurons spot these errors, it has been unclear whether there are brain cells that have only one job—to signal when a sound is unexpected or "off."

A team of neuroscientists has now identified a class of neurons—what it calls "prediction-error neurons"—that are not responsive to sounds in general, but only respond when sounds violate expectations, thereby sending a message that a mistake has been made.

Brains are remarkable at detecting what's happening in the world, but they are even better at telling you whether what happened was expected or not. It 's found that there are specific neurons in the brain that don't tell you what happened, but instead tell you what went wrong. Neurons like these might be vital in learning how to speak or how to play a musical instrument. Both of those behaviors involve lots of trial and error, lots of mistakes, and lots of learning from mistakes

Nicholas J. Audette et al, Stimulus-specific prediction error neurons in mouse auditory cortex, The Journal of Neuroscience (2023). DOI: 10.1523/JNEUROSCI.0512-23.2023

Unique voice prints in parrots could help birds be recognized in a flock, no matter what they say

Parrots are exceptional talkers. They can learn new sounds during their entire lives, amassing an almost unlimited vocal repertoire. At the same time, parrots produce calls so they can be individually recognized by members of their flock—raising the question of how their calls can be very variable while also uniquely identifiable.

A study on monk parakeets might have the answer: individuals have a unique tone of voice, known as a voice print, similar to that in humans. This finding in a wild parrot raises the possibility that a voice print might also be present in other vocally flexible species, such as dolphins and bats.

It makes sense for monk parakeets to have an underlying voice print. It's an elegant solution for a bird that dynamically changes its calls but still needs to be known in a very noisy flock.

Humans have complex and flexible vocal repertoires, but we can still recognize each other by voice alone. This is because humans have a voice print: our vocal tract leaves a unique signature in the tone of our voice across everything that we say.

Other social animals also use vocal cues to be recognized. In birds, bats, and dolphins, for example, individuals have a unique "signature call" that makes them identifiable to members of the group. But signature calls encode identity in only one call type. To date, almost no evidence exists for animals having unique signatures that underlie all calls made by an individual. In other words, almost no animals are known to have a voice print.

Like humans, parrots use their tongue and mouth to modulate calls, meaning that their grunts and shrieks sound much more human than a songbird's clean whistle.

Also, like humans, parrots live in large groups with fluid membership. There could be tens of birds vocalizing at the same time. They need a way of keeping track of which individual is making what sound.

Part 1

Armed with shotgun microphones, researchers recorded the calls of hundreds of individuals, collecting over 5000 vocalizations in total, making it the largest study of individually-marked wild parrots to date. Importantly, they re-recorded the same individuals over two years, which revealed how stable the calls were over time.

They then used a set of models to detect how recognizable individuals were within each of the five main call types given by this species. Surprisingly, they found high variability in the so-called "contact call" that birds use to broadcast their identity. This overturned a long-held assumption that contact calls contain a stable individual signal—and suggested that the parakeets are using something else for individual recognition.
To test if voice prints were at play, scientists turned to a machine learning model widely used in human voice recognition, which detects the identity of the speaker using the timber of their voice. They trained the model to recognize calls of individual parrots that were classed as "tonal" in sound.
Once the model was trained on an individual, they then tested to see if the model could detect the same individual from a different set of calls that were classed as "growling" in sound. The model was able to do this three times better than expected by chance, providing evidence that monk parakeets have a voice print, which could allow individuals to recognize each other no matter what they say.

The researchers, however,  caution that the evidence is still preliminary. Before we can speak of a true voice print, we need to confirm that the model can repeat this result when it is trained with more data from more individuals, and that birds can also recognize this timbre in the vocalizations.

Simeon Smeele et al, Evidence for vocal signatures and voice-prints in a wild parrot, Royal Society Open Science (2023). DOI: 10.1098/rsos.230835. royalsocietypublishing.org/doi/10.1098/rsos.230835

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Part 2

Common Plastic Additive Linked to Autism And ADHD

The number of kids being diagnosed with autism spectrum disorder ( ASD) and attention deficit hyperactivity disorder ( ADHD) has risen sharply in recent decades, and a new study points to the common plastic additive bisphenol A (BPA) as a potential reason why. BPA is used in a lot of plastics and plastic production processes, and can also be found inside food and drink cans. However, previous research has also linked it to health issues involving hormone disruption, including breast cancer and infertility.

In this new study, researchers from Rowan University and Rutgers University in the US looked at three groups of children: 66 with autism, 46 with ADHD, and 37 neurotypical kids. In particular, they analyzed the process of glucuronidation, a chemical process the body uses to clear out toxins within the blood through urine.
The research found that kids with ASD and ADHD couldn't clear out BPA and another similar compound called Diethylhexyl Phthalate (DEHP) with as much efficiency as other kids, potentially leading to longer exposure to their toxic effects.

"Detoxification of these two plasticizers is compromised in children with ASD and ADHD," write the researchers in their published paper. "Consequently, their tissues are more exposed to these two plasticizers."

It was only in the case of BPA that the difference was statistically significant though: the efficiency was reduced by about 11 percent for kids with ASD and 17 percent for kids with ADHD, compared with the control group of children.
Part 1

The researchers think that gene mutations in certain individuals means that BPA can't be cleared as well as it needs to be, which means the substance sticks around in the body. That potentially could cause damage in terms of neuron development and operation.

Conditions like ASD and ADHD are thought to be brought on by a combination of genetic and environmental influences, and this new study brings together both of them. However, it's only part of the story – not every child with a neurodevelopmental disorder had problems flushing out BPA, so there are other factors at play, too.

Work is continuing to identify how exactly ASD and ADHD take hold in the body – whether it's in utero before birth for example, or later on in life – as the data isn't enough to show whether BPA exposure causes either disorder.

"There is an extensive body of epidemiological evidence for a relationship between neurodevelopmental disorders and environmental pollutants such as plasticizers," write the researchers.

"How important plasticizer originated neurodevelopmental disorder is in the overall occurrence of these disorders is not known, but it must account for a significant proportion or would not have been so easy to detect in a metabolic study of moderate size such as this study."

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0...

Part 2

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Digital watermark protections can be easily bypassed

Perhaps the most chilling aspect of AI is its capacity to generate deepfake images.

But recent developments portend a more unsettling trend as digital fakery turns malicious. Not only celebrities and politicians, ordinary citizens are targeted, too. People's faces are appearing in images on social media without their consent. 

Major digital media companies—OpenAI, Alphabet, Amazon, DeepMind—have promised to develop tools to combat disinformation. One key approach is the use of watermarking on AI-generated content.

A paper published Sept. 29 on the preprint server arXiv raises troubling news about the ability to curb such digital abuse.

Researchers ran tests demonstrating easy run-arounds of protective watermarks.

We don't have any reliable watermarking at this point because the researchers broke them all!

The team used a process called diffusion purification, which applies Gaussian noise to a watermark and then removes it. It leaves a distorted watermark that can bypass detection algorithms. The rest of the image is only minimally altered.

They further successfully demonstrated that bad actors with access to black-box watermarking algorithms could foist fake photos with markings that trick detectors into believing they are legitimate.

Better algorithms will certainly come along. As has been the case with viral attacks, the bad guys will always be working to break whatever defenses the good guys come up with, and the cat-and-mouse game will continue.

Mehrdad Saberi et al, Robustness of AI-Image Detectors: Fundamental Limits and Practical Attacks, arXiv (2023). DOI: 10.48550/arxiv.2310.00076

How synthesized plankton molecules inhibit cancer proteins

Researchers have discovered how to harness the toxic power of plankton to manufacture anti-cancer molecules.

In a paper, "Synthesis of portimines reveals the basis of their anti-cancer activity," published in Nature, the team details the steps taken in synthesizing marine toxins, portimine A and portimine B, enabling in-depth investigations into their properties

Dinoflagellate-derived cyclic imine toxins, specifically portimine A and portimine B, are of interest due to their potential anti-cancer therapeutic properties. Previous research has shown the effects of cyclic imine toxins on cancer cells, but the molecular mechanisms underlying the cause of the anti-cancer activity were unknown. Access to these toxins in large quantities is currently hard to come by as the only known producer is a type of tiny marine plankton, Vulcanodinium rugosum. To test the toxin's activity, the researchers first needed to innovate a way to synthesize large enough quantities to work with.

The synthesis began with constructing a minimally-decorated carbon skeleton devoid of most oxygen atoms. The idea was to leverage a macrocycle's innate reactivity to install the correct oxygenation pattern and stereochemistry.

Strategic ring-chain tautomerization events were employed to facilitate the synthesis using ring-closing alkyne metathesis to construct the 14-membered macrocycle in the portimines' skeleton. The innovation represents a scalable and concise synthesis of portimines. With the desired molecules created, the next step was to see how they interacted with cancer cells.

Part 1

The team tested interactions across a broad panel of 20 human and mouse cancer cell lines, ranging from Jurkat leukemia to metastatic human fibrosarcoma cells, triple-negative breast cancer and glioblastoma brain-tumor-initiating cell lines. Consistent potent cytotoxic activity was observed across the entire panel of cancer cell lines that were evaluated with portimine A. The fully synthetic portimine B was found to be substantially less effective.

Portimine A was identified as a potent inducer of apoptosis in various cancer cell lines, including MC38 cells, a colorectal carcinoma testing model. The apoptosis caused by portimine A had minimal effects on non-cancerous cells and low toxicity in mice.
Specifically, portimine A was found to target the 60S ribosomal export protein NMD3, blocking polysome formation and inhibiting protein translation and was observed to be an effective agent for suppressing tumor growth in vivo.

The exposure time to portimine A was limited by its half-life of around 30 minutes. The short duration still resulted in a significant reduction in tumor growth, indicating a very potent activity and potential therapeutic uses in the future.

Junchen Tang et al, Synthesis of portimines reveals the basis of their anti-cancer activity, Nature (2023). DOI: 10.1038/s41586-023-06535-1

The chemical synthesis and anti-cancer properties of portimines, Nature (2023). DOI: 10.1038/d41586-023-02788-y

Part 2

Study challenges the rules of evolutionary biology

Charles Darwin said that evolution was constantly happening, causing animals to adapt for survival. But many of his contemporaries disagreed. If evolution is always causing things to change, they asked, then how is it that two fossils from the same species, found in the same location, can look identical despite being 50 million years apart in age?

Everything changed in the past 40 years, when an explosion of evolutionary studies proved that evolution can and does occur rapidly—even from one generation to the next. Evolutionary biologists were thrilled, but the findings reinforced the same paradox: If evolution can happen so fast, then why do most species on Earth continue to appear the same for many millions of years?

This is known as the paradox of stasis and researchers set out to investigate it. 

  They conducted a long-term study in a community of lizards, measuring how evolution unfolds in the wild across multiple species. In doing so, he may have found the answer to one of evolution's greatest challenges.

The research was published as the cover story in the Proceedings of the National Academy of Sciences.

Scientists call this a paradox because it doesn't seem to make any sense. The most common explanation is that natural selection  is working to stabilize a species' appearance, with the assumption that an average form will help them survive the best. The problem is, when people do field studies, they almost never find that this kind of 'stabilizing' selection actually exists

Part 1

Scientists set up a field study with four different species of Anolis lizards (anoles) on a small island at the Fairchild Tropical Botanic Gardens in Coral Gables, Florida. They measured natural selection in all four lizard species over five consecutive time periods by catching and monitoring the survival of every lizard on the island.

The researchers searched day and night for lizards. Using long fishing poles with tiny lassos at their tips, they gently captured them by their strong necks, placed them in coolers, and documented the exact branch or stump where they found each lizard.

Back in the lab, they measured the lizards' heads, legs, feet, weight, and even the stickiness of their toes. After assigning an identifying number to each lizard and marking them with a tiny tag under the skin, the team released the lizards to the same branches where they'd found them. They went out in the following days and weeks to catch the rest of them.

Every six months for three years, the researchers started the process over again. Catching the same lizards, taking measurements, releasing them, and making notes of which lizards survived and which didn't.

For a very long time, evolutionary biologists have tried to figure out what was behind this paradox of stasis idea," the scientists said. "What this study shows is that the answer may not be particularly complicated—we just had to conduct a study in the wild for a long enough time to figure it out."

Stroud, James T. et al, Fluctuating selection maintains distinct species phenotypes in an ecological community in the wild, Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2222071120. doi.org/10.1073/pnas.2222071120

Part 3

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Firefighting Fungi
Underneath every mushroom is a sprawling, branching network of rootlike structures called a mycelium. Now researchers have successfully grown these networks into Pop Tart–size sheets that could act as a fire retardant in building materials. Mycelium contains a lot of carbon. When exposed to fire, the sheet briefly burns, releasing water and carbon dioxide into the air, before petering out and leaving behind a black layer of carbon.

Why this is so cool: Unlike asbestos, which is still sometimes added to building materials as a fire retardant, mycelium does not shed noxious compounds when exposed to fire. Mycelium could replace the fire-retardant foam that insulates many commercial buildings, which can produce carbon monoxide and other toxic products when it combusts. Mycelium is also a biological material, and any waste it leaves behind is compostable.

What the experts say: “If the product reaches the end of its life, you can just chuck that mycelium in your garden,” says Everson Kandare an engineer at RMIT University in Melbourne, Australia. “Just toss it in the green beans.”

Remnant of cell division could be responsible for spreading cancer

Once thought to be the trash can of the cell, a little bubble of cellular stuff called the midbody remnant is actually packing working genetic material with the power to change the fate of other cells—including turning them into cancer.

When one cell divides into two, a process called mitosis, the result is not just the two daughter cells.

One cell divides into three things: two cells and one midbody remnant, a new signaling organelle. The midbody is full of genetic information, RNA, that doesn't have much to do with cell division at all, but likely functions in cell communication.

Researchers  analyzed the contents of midbodies—which form between the daughter cells during division—and tracked the interactions of the midbody remnants set free after cell division. Their results point to the midbody as a vehicle for the spread of cancer throughout the body.

What the researchers found inside midbodies was RNA—which is a kind of working copy of DNA used to produce the proteins that make things happen in cells—and the cellular machinery necessary to turn that RNA into proteins. The RNA in midbodies tends to be blueprints not for the cell division process but for proteins involved in activities that steer a cell's purpose, including pluripotency (the ability to develop into any of the body's many different types of cells) and oncogenesis (the formation of cancerous tumours).

A midbody remnant is very small. It's a micron in size, a millionth of a meter. But it's got everything it needs to sustain that working information from the dividing cell. And it can drift away from the site of mitosis, get into your bloodstream and land on another cell far away.

Part 1

Many midbody remnants are reabsorbed by one of the daughter cells that shed them, but those that touch down on a distant surface, like a lunar lander, may instead be absorbed by a third cell. If that cell swallows the midbody, it may mistakenly begin using the enclosed RNA as if it were its own blueprints.

Previous research showed that cancer cells are more likely than stem cells to have ingested a midbody and its potentially fate-altering cargo. Stem cells, which give rise to new cells and are valuable for their pluripotency, spit a lot of midbodies back out, perhaps to maintain their pluripotency.

Future research may be able to harness the power of midbody RNA to deliver drugs to cancer cells or to keep them from dividing.

The researchers identified a gene, called Arc, that is key to loading the midbody and midbody remnant with RNA. Taken up long ago from an ancient virus, Arc also plays a role in the way brain cells make memories.

Sungjin Park et al, The mammalian midbody and midbody remnant are assembly sites for RNA and localized translation, Developmental Cell (2023). DOI: 10.1016/j.devcel.2023.07.009

Part 2

Vacuum cleaner-effect in fungi can hold nanoplastics at bay

Researchers have investigated the effect of tiny polystyrene particles on bacteria and fungi. While these nanoplastics reduced both bacterial and fungal growth, the fungus actually managed to "clean up" their surroundings, thereby easing the effect of the plastics. 

Nanoplastics have been proven to induce toxicity in diverse organisms, yet very little is known how this new pollutant is affecting the soil ecosystem. To study these nanoparticles of polystyrene, the researchers used microfluidic chips, a growth system that allowed them to observe interactions of single cells with the plastics under the microscope.

At the highest nanoplastics concentration, the fungi caught most of the tiny plastics present in their vicinity, in a process that  the researchers labeled the 'vacuum cleaner effect.' Overall, they found that nanoplastics can cause a direct negative effect on the soil microbes. This highlights the need for further studies that can explain how the microbial stress response might affect soil functions.

The nanoplastic particles clung to the surface of the fungal branches in such a way that the surroundings were almost nanoplastic-free. The fungus cleaned up its surroundings under high concentrations, and could then grow better again. Although the results of the study were confirmed for many conditions, the researchers point out that it might be species dependent.

This serves as a reminder to reduce our plastic waste and the pollution of soils. Finding fungi that can specifically collect nanoplastics from the soil solution may help other organisms to sustain the pollution better, and perhaps attract bacteria that can break down plastics. The fungal 'vacuum cleaner' is not an easy fix for the problem, but can give a little hope for the future.

Paola M. Mafla-Endara et al, Exposure to polystyrene nanoplastics reduces bacterial and fungal biomass in microfabricated soil models, Science of The Total Environment (2023). DOI: 10.1016/j.scitotenv.2023.166503

Models suggest interlinking rivers in India to meet water demand may adversely impact monsoon rainfall amounts

A team of civil engineers and meteorologists at the Indian Institute of Technology, working with colleagues from the Indian Institute of Tropical Meteorology and the University of Hyderabad, has found, via modeling, that a plan to interlink rivers in India to capture rain runoff could inadvertently have a negative impact on the amount and location of monsoon rainfall.

In their study, published in the journal Nature Communications, the group used a variety of modeling techniques to test the possibility of unintended changes to weather patterns in India as interlinking projects are undertaken.

Officials in India have a clear problem on their hands—their country has a population of 1.4 billion people, the highest of any country in the world. And it is still growing. Such growth is presenting a host of problems, including how to feed so many people, sustain economic growth and manage water. This last problem has become dire—for India to feed its people, it must grow more food and that will require more water. But water availability is decreasing. To meet the demand, scientists and government officials have proposed and instigated a plan that entails digging canals between rivers to interlink them, with the idea of capturing more rainfall. Instead of allowing most of its rainfall to run off into rivers and then to the sea, the country plans to divert some of that water into other rivers that can be shunted into drier areas, where it can be used for irrigation. But doing so, the researchers on this new effort insist, could have unintended and perhaps disastrous side effects.

Part 1

Prior research has shown that exchange of material such as aerosols into the atmosphere can lead to a land-atmospheric feedback system, resulting in cooling of temperatures in a region, and subsequent changes in rainfall amounts. Likewise, irrigation efforts have been found to instigate land-atmosphere feedback as water from such systems evaporates into the atmosphere. Such systems have been found to have an impact on local hydrological cycles, and in some cases, can impact monsoon rains. These findings convinced the team on this new effort to take a closer look at the possible impact of interlinking rivers.

To estimate possible impacts, the team used causal delineation techniques along with general climate models that have been modified to focus specifically on India and its weather, and also a reanalysis of datasets built from land-atmosphere feedback systems that already exist in India.

The researchers found that land-atmosphere feedbacks from interlinked rivers could generate causal pathways between river basins in India—as one example, they found incidences of decreased rainfall in September (during monsoon season) by up to 12% in parts of the country that are already experiencing water shortages. They also found evidence of some areas experiencing more dryness during El Niño years. They conclude that more study is required before approving new river linking efforts.

Tejasvi Chauhan et al, River interlinking alters land-atmosphere feedback and changes the Indian summer monsoon, Nature Communications (2023). DOI: 10.1038/s41467-023-41668-x

Part 2

Why eyeballing four is easy but five is hard

Our brains use one mechanism to size up four or fewer items, and a different one f... — which is why doing the latter is so much harder. The brain contains specialized neurons that fire when we see a specific number of objects: some fire primarily when presented with one dot on a screen, for example. Brain scans of 17 people revealed that the neurons specializing in numbers of four or less responded very specifically and selectively to their preferred number. Neurons that specialize in five through nine responded strongly not only to their preferred number, but also to numbers immediately adjacent to it.

https://www.nature.com/articles/s41562-023-01709-3.epdf?sharing_tok...

Copycat nutrient leaves pancreatic tumors starving

A study by scientists suggests an entirely new approach to treat pancreatic cancer. The research shows that feeding tumors a copycat of an important nutrient starves them of the fuel they need to survive and grow. The method, described in the journal Nature Cancer, has been used in early clinical trials for lung cancer. However, the unique properties of pancreatic cancer may make the strategy an even stronger candidate in the pancreas.

Pancreatic cancer relies on the nutrient glutamine much more than other cancers, so therapies that can interfere with tumors' ability to access glutamine could be highly effective.

Pancreatic cancer is relatively rare, accounting for only 3% of all cancers. However, it has one of the lowest survival rates among cancers: most people only live three to six months after being diagnosed with this disease.

One of the challenges of treating pancreatic cancer has to do with the physical properties of the tumors themselves.

Pancreatic tumors tend to be packed in dense connective tissue that keeps them encapsulated from the rest of the body and cuts off their supply of oxygen. As a consequence, these cancers develop unique metabolic properties compared to other tumors, and this is something we may be able to exploit with new treatments.

Part 1

One of the metabolic quirks of pancreatic cancer is that it relies heavily on glutamine to produce energy for growth and survival. In the past, scientists have tried to block access to glutamine to slow the growth of pancreatic tumors, but this is easier said than done.

The new method relies on a molecule called DON that has structural similarities to glutamine but can't actually be used as a nutrient source. By studying mice, the research team found that DON significantly slowed pancreatic tumour growth and stopped the tumors from spreading.

Although DON was able to stop pancreatic tumors from using glutamine, pancreatic cancer cells can use other nutrients to grow in glutamine's absence. To combat this effect, the researchers combined DON with an existing cancer treatment that blocks the metabolism of asparagine, another important nutrient. The combined treatment had a synergistic effect, helping prevent the spread of pancreatic tumors to other distant organs, such as the liver and lungs.

This could be a game changer for pancreatic cancer, and a lot of the preclinical work needed to rationalize it and is already happening.

Maria Victoria Recouvreux et al, Glutamine mimicry suppresses tumor progression through asparagine metabolism in pancreatic ductal adenocarcinoma, Nature Cancer (2023). DOI: 10.1038/s43018-023-00649-1

Part 2

Evidence that albatrosses use infrasound to navigate long journeys

A new study  provides the first evidence that wandering albatrosses, one of the widest-ranging seabirds, may use infrasound to help them navigate long and featureless foraging trips covering thousands of miles.

Researchers show that albatrosses  orientate towards areas of "loud" microbarom infrasound when flying on long distance foraging trips. The paper published on this work is titled "Albatross movement suggests sensitivity to infrasound cues at sea."

Infrasound is a form of low-frequency sound that is inaudible to humans but is ubiquitous in the marine environment. Microbaroms are a type of infrasound associated with colliding ocean waves. Such wavy areas are also associated with strong winds, which albatrosses depend on to help them fly efficiently. The researchers used GPS trackers to determine the flight paths of 89 wandering albatrosses breeding in the Crozet Islands archipelago, Southern Ocean, over the course of their foraging trips to sea, which can last up to a month. They then compared these flight paths to modeled acoustic maps that the team had developed to represent the distribution of microbarom infrasound.

This revealed that wandering albatrosses orientate towards areas of "loud" microbarom infrasound when departing on bouts of directed flight, suggesting that they may perceive and respond to microbarom infrasound propagated over long distances.

 Natasha Gillies et al, Albatross movement suggests sensitivity to infrasound cues at sea, Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2218679120

How plant-derived nutrients can affect the gut and brain

Can plant-derived nutrients alter gut bacteria to affect brain function? Scientists investigated this question in a study of overweight adults.

Their findings, published in the journal Gut, suggest that dietary fiber can exert influence on both the composition of gut bacteria and the reward signals in the brain and associated food decision-making. Prebiotics are used to foster the colonization of beneficial bacteria in the gut. These indigestible dietary fibers are found in plant-derived foods such as onions, leeks, artichokes, wheat, bananas, and in high concentrations in chicory root. They support gut health by promoting the growth and activity of beneficial gut bacteria. Researchers have now investigated whether certain prebiotics can also influence brain function by improving communication between the gut microbiome and the brain.

The study shows consumption of high-dose dietary prebiotics leads to a reduction in reward-related brain activation in response to high-calorie food stimuli. The results suggest a potential link between gut health and brain function, in this case food decision-making.

The findings, derived from advanced neuroimaging, next-generation sequencing of gut bacteria, and combined analyses of potential metabolic pathways, suggest that functional microbial changes may underlie the altered brain response towards high-caloric food cues. 

A better understanding of the underlying mechanisms between the microbiome, gut, and brain could help to develop new strategies that promote healthier eating habits in people at risk.

Evelyn Medawar et al, Prebiotic diet changes neural correlates of food decision-making in overweight adults: a randomised controlled within-subject cross-over trial, Gut (2023). DOI: 10.1136/gutjnl-2023-330365

Study shows live plant pathogens can travel on dust across oceans

Plant pathogens can hitch rides on dust and remain viable, with the potential for traveling across the planet to infect areas far afield, a finding with important implications for global food security and for predicting future outbreaks.

A study, "Assessing Long-distance Atmospheric Transport of Soilborne Plant Pathogens," published in the journal Environmental Research Letters, is the first to provide computer modeling evidence to support the idea that massive dust storms can transport viable pathogenic spores across continents and oceans.

The researchers found that viable spores of the deadly fungal plant pathogen Fusarium oxysporum (F. oxy) could be transported across the ocean and were likely deposited across a range of regions that include agricultural production zones.

The researchers found that this Godzilla ( a major dust storm) dust event could have potentially brought over 13,000 viable live spores, which is not a lot, but it's never been shown before, by any means, that viable soilborne pathogens could be transported trans-oceanically with dust.

Hannah Brodsky et al, Assessing long-distance atmospheric transport of soilborne plant pathogens, Environmental Research Letters (2023). DOI: 10.1088/1748-9326/acf50c

Сoconut shells can make concrete more durable

Scientists have found that concrete's compressive strength can be increased by 4.1% and its flexural strength by 3.4% by adding a small amount of coconut shell (only 5%). The material's performance increased by 6.1% compared to clear concrete. This effect is due to the fact that the cement paste—the bridge between all solid concrete particles—penetrates into the pores of the shell, firmly binding it with other components.

These results show that large amounts of coconut shell can be recycled without harm to the environment while improving the quality of building materials.

Sergey A. Stel'makh et al, Alteration of Structure and Characteristics of Concrete with Coconut Shell as a Substitution of a Part of Coarse Aggregate, Materials (2023). DOI: 10.3390/ma16124422

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Animals find humans scarier than lions

Human voices evoke more fear among animals living in the South African savanna than do snarls from lions. Researchers set up speakers near 21 water holes, which played one of several sounds when triggered by animal movement. When they heard humans, giraffes, leopards, elephants and 16 other species were twice as li... as when they heard growling lions, barking dogs or guns. The researchers suggest that recordings of human voices could be used to keep animals away from areas where a lot of poaching happens.

https://www.cell.com/current-biology/fulltext/S0960-9822(23)01169-7?utm_source=Nature+Briefing&utm_campaign=00a3d0b50b-briefing-dy-20231010&utm_medium=email&utm_term=0_c9dfd39373-00a3d0b50b-44672165

Bionic hand merges with user's nervous and skeletal systems, remaining functional after years of daily use

A woman's life took a dramatic turn when a farming accident claimed her right arm more than 20 years ago. Since then, she has endured excruciating phantom limb pain.

In addition to her intractable pain, she found that conventional prostheses were uncomfortable and unreliable, and thus of little help in daily life. All this changed when she received groundbreaking bionic technology that allowed her to wear a much more functional prosthesis comfortably all day. The higher integration between the bionics and her residual limb also relieved her pain. 

Mechanical attachment and reliable control are two of the biggest challenges in artificial limb replacement. People with limb loss often reject even the sophisticated prostheses commercially available due to these reasons, after experiencing painful and uncomfortable attachment with limited and unreliable controllability. A multidisciplinary group of engineers and surgeons solved these problems by developing a human–machine interface that allows the prosthesis to be comfortably attached to the user's skeleton via osseointegration, while also enabling electrical connection with the nervous system via electrodes implanted in nerves and muscles. This research is now published in the journal Science Robotics.

 Max Ortiz-Catalan et al, A highly integrated bionic hand with neural control and feedback for use in daily life, Science Robotics (2023). DOI: 10.1126/scirobotics.adf7360. www.science.org/doi/10.1126/scirobotics.adf7360

NASA asteroid sample contains life-critical water and carbon

A sample collected from the 4.5-billion-year-old asteroid Bennu contains abundant water and carbon, NASA revealed on Wednesday, offering more evidence for the theory that life on Earth was seeded from outer space

The discovery follows a seven-year-round-trip to the distant rock as part of the OSIRIS-REx mission, which dropped off its precious payload in the Utah desert last month for painstaking scientific analysis.

"This is the biggest carbon-rich asteroid sample ever returned to Earth," NASA administrator Bill Nelson said at a press event at the Johnson Space Center in Houston, where the first images of black dust and pebbles were revealed.

Carbon accounted for almost five percent of the sample's total weight, and was present in both organic and mineral form, while the water was locked inside the crystal structure of clay minerals, he said.

Scientists think the reason Earth has oceans, lakes and rivers is because it was hit with water-carrying asteroids 4 to 4.5 billion years ago, making it a habitable planet.

All life on Earth meanwhile is based on carbon, which forms bonds with other elements to produce proteins and enzymes as well as the building blocks of genetic code, DNA and RNA.

The findings were made through a preliminary analysis involving scanning electron microscopy, X-ray computed tomography and more.

Research finds commonly-used herbicide is harmful to adolescent brain function

Herbicides are the most used class of pesticides worldwide, with uses in agriculture, homes and industry. Exposures to two of the most popular herbicides were associated with worse brain function among adolescents, according to a study  by researchers.

 Researchers reported measuring metabolite concentrations of two commonly used herbicides—glyphosate and 2,4-dichlorophenoxyacetic acid (2,4D)—and the insect repellent DEET in urine samples collected in 2016 from 519 adolescents, aged 11 to 17, living in the agricultural county of Pedro Moncayo, Ecuador. Researchers also assessed neurobehavioral performance in five areas: attention and inhibitory control, memory and learning, language, visuospatial processing, and social perception.

Many chronic diseases and mental health disorders in adolescents and young adults have increased over the last two decades worldwide, and exposure to neurotoxic contaminants in the environment could explain a part of this increase, according to the researchers. 

Part 1

Among the findings:

• Glyphosate, a nonselective herbicide used in many crops, including corn and soy, and for vegetation control in residential settings, was detected in 98% of participants.
• 2,4D, a broadleaf herbicide used on lawns, aquatic sites, and agricultural crops, was detected in 66% of participants.
• Higher amounts of 2,4D in urine were associated with lower neurobehavioral performance in the domains of attention and inhibitory control, memory and learning, and language.
• Glyphosate concentration in urine was associated with lower scores in social perception only, while DEET metabolites were not associated with neurobehavioral performance.

Following the introduction of genetically modified, glyphosate-resistant "Roundup-ready" crops in 1996 and 2,4D resistant crops in 2014, there have been substantial increases in glyphosate and 2,4D use, making them the most widely used herbicides in the world, they wrote in a published paper.

Briana Chronister et al, Urinary glyphosate, 2,4-D and DEET biomarkers in relation to neurobehavioral performance in Ecuadorian adolescents in the ESPINA cohort, Environmental Health Perspectives (2023). DOI: 10.1289/EHP11383

Part 2

Birds disperse eaten insects' eggs

Relationship patterns among flightless stick insects suggest that birds disperse the eggs after eating gravid females. Now this is shown to be true in a new study.

 Most species of stick insects are flightless, yet they are distributed over wide distances and across geographical features that would impede the expansion of flightless animals. This has caused researchers to think that their eggs might be dispersed by birds feeding on gravid females, much in the same way as many plant species rely on birds eating their seeds together with fruits and dispersing them while the seeds pass through the digestive tracts of the birds unharmed.

Experimental studies with Ramulus mikado, a common stick insect in Japan, had suggested that this is possible, but since direct observation of such an event in nature is highly unlikely, it has been unclear whether this mechanism actually contributes to the distribution of the insect.

So researchers turned to the analysis of the relationship patterns of Ramulus mikado populations. They made use of the idea of genetic isolation by geographic distance. 

According to this idea, when individual dispersal distances are smaller, such as in flightless insects, the accumulation of genetic mutations eventually leads to a positive correlation between genetic differentiation among locations and the geographic distance that separates them. Thus, the genetic variation between different populations can be a proxy for the species' rate of dispersal.

The results, published in the journal Proceedings of the Royal Society B, paint a vivid picture. Among many genes where the differences correlated with the geographic distance, the team found a few examples of genes that were clearly closely related even though they were geographically separated by up to hundreds of kilometers and across geographic features that these animals usually cannot overcome.

Astonishingly, amidst a sea of limited active dispersal, they discovered identical genotypes jumping across vast distances, strongly indicating the past occurrence of passive long distance genetic dispersal.

In other words, a few of the flightless insects must have flown from place to place, and the only plausible way in which this could happen is that the eggs of the insects survive the passage through the digestive tract of birds that eat them.

And the insect eggs were seen in bird faeces. 

Part 1

Why this type of dispersal not seen among other insects? 

The eggs of most insect species are typically fertilized just before being laid, relying on sperm stored within the female insects after copulation. However, in some stick insect species, females are parthenogenic, that is, they can produce viable eggs without fertilization. It is only because of this quirk in their nature that viable stick insect babies can hatch from the eggs.

Suetsugu Kenji et al, Phylogeographical evidence for historical long-distance dispersal in the flightless stick insect Ramulus mikado, Proceedings of the Royal Society B: Biological Sciences (2023). DOI: 10.1098/rspb.2023.1708. royalsocietypublishing.org/doi … .1098/rspb.2023.1708

Part 2

Gene editing makes chickens flu-resistant

Bird-flu-resistant chickens have been created using CRISPR gene editing. When exposed to the flu virus, nine out of ten of the animals remained uninfected and didn’t pass the virus to other birds. Researchers modified a gene encoding a chicken protein that the virus needs to replicate. But this prompted the virus to start replicating using other proteins in the same family, which the researchers think could be addressed with more edits. “We must be careful not to facilitate adaptations of the virus that make it more dangerous than it [already] is,” says virologist and study co-author Wendy Barclay.

https://english.elpais.com/science-tech/2023-10-10/the-same-lab-tha...

https://www.nature.com/articles/s41467-023-41476-3.epdf?sharing_tok...

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Simulations of 'backwards time travel' can improve scientific experiments

Physicists have shown that simulating models of hypothetical time travel can solve experimental problems that appear impossible to solve using standard physics.

If gamblers, investors and quantum experimentalists could bend the arrow of time, their advantage would be significantly higher, leading to significantly better outcomes. Researchers at the University of Cambridge have shown that by manipulating entanglement—a feature of quantum theory that causes particles to be intrinsically linked—they can simulate what could happen if one could travel backwards in time. So that gamblers, investors and quantum experimentalists could, in some cases, retroactively change their past actions and improve their outcomes in the present. Whether particles can travel backwards in time is a controversial topic among physicists, even though scientists have previously simulated models of how such spacetime loops could behave if they did exist. By connecting their new theory to quantum metrology, which uses quantum theory to make highly sensitive measurements, the Cambridge team has shown that entanglement can solve problems that otherwise seem impossible.

 David R. M. Arvidsson-Shukur et al, Nonclassical Advantage in Metrology Established via Quantum Simulations of Hypothetical Closed Timelike Curves, Physical Review Letters (2023). DOI: 10.1103/PhysRevLett.131.150202

Study finds we can respond to verbal stimuli while sleeping

Sleep is not a state in which we are completely isolated from our environment: while we sleep, we are capable of hearing and understanding words. These observations, the result of close collaboration between various research teams call into question the very definition of sleep and the clinical criteria that make it possible to distinguish between its different stages.

Sleep is generally defined as a period during which the body and mind are at rest—as if disconnected from the world. However, a new study shows that the frontier between wakefulness and sleep  is much more porous than it seems.

The researchers have shown that ordinary sleepers can pick up verbal information transmitted by a human voice and respond to it by contracting their facial muscles. This astonishing ability occurs intermittently during almost all stages of sleep—like windows of connection with the outside world were temporarily opened on this occasion. These new findings suggest that it may be possible to develop standardized communication protocols with sleeping individuals to understand better how mental activity changes during sleep. On the horizon: a new tool to access the cognitive processes that underlie both normal and pathological sleep.

Part 1

Even if it seems familiar because we indulge in it every night, sleep is a highly complex phenomenon. Our research has taught us that wakefulness and sleep are not stable states: on the contrary, we can describe them as a mosaic of conscious and seemingly unconscious moments. It is essential to decipher the brain mechanisms underlying these intermediate states between wakefulness and sleep. "When they are dysregulated, they can be associated with disorders such as sleepwalking, sleep paralysis, hallucinations, the feeling of not sleeping all night, or on the contrary of being asleep with your eyes open.

To distinguish between wakefulness and the different stages of sleep, researchers usually use physiological indicators such as specific brain waves made visible through electroencephalography. Unfortunately, these indicators do not provide a detailed picture of what is happening in the minds of sleepers; sometimes, they even contradict their testimonies.

Part 2

To explore this avenue, the researchers recruited 22 people without sleep disorders and 27 patients with narcolepsy—that is, people who experience uncontrollable episodes of daytime sleepiness. People with narcolepsy have the particularity of having many lucid dreams,  in which they are aware of being asleep; some can sometimes even shape their dream scenario as they wish.

In addition, they easily and quickly enter REM sleep (the stage where lucid dreaming occurs) during the day, making them good candidates for studying consciousness during sleep under experimental conditions.

Participants in the study were asked to take a nap. The researchers gave them a "lexical decision" test, in which a human voice pronounced a series of real and made-up words. Participants had to react by smiling or frowning to categorize them into one or the other of these categories. Throughout the experiment, they were monitored by polysomnography—a comprehensive recording of their brain and heart activity, eye movements, and muscle tone.

Upon waking up, participants had to report whether they had or had not had a lucid dream during their nap and whether they remembered interacting with someone.

Most of the participants, whether narcoleptic or not, responded correctly to verbal stimuli while remaining asleep. These events were certainly more frequent during lucid dreaming episodes, characterized by a high level of awareness. 

By cross-referencing these physiological and behavioral data and the participants' subjective reports, the researchers also showed that it is possible to predict the opening of these windows of connection with the environment, i.e., the moments when sleepers were able to respond to stimuli. They were announced by an acceleration in brain activity and by physiological indicators usually associated with rich cognitive activity.

Türker B. et al. Behavioral and brain responses to verbal stimuli reveal transient periods of cognitive integration of the external world during sleep. Nature Neuroscience (2023). DOI: 10.1038/s41593-023-01449-7. www.nature.com/articles/s41593-023-01449-7

Part 3

Restoring nerve-muscle connections boosts strength of aging mice, study finds

A small molecule previously shown to enhance strength in injured or old laboratory mice does so by restoring lost connections between nerves and muscle fibers,  researchers have found.

The molecule, called PGE2, blocks the activity of an aging-associated enzyme, or gerozyme, called 15-PGDH that naturally increases in muscles as they age. The study showed that levels of the gerozyme increase in muscles after nerve damage and that it is prevalent in muscle fibers of people with neuromuscular diseases. The research is the first to show that damaged motor neurons—nerves connecting the spinal cord to muscles—can be induced to regenerate in response to a drug treatment and that lost strength and muscle mass can be at least partially regained. It suggests that, if similar results are seen in humans, the drug may one day be used to prevent muscle loss of muscle strength due to aging or disease or to hasten recovery from injury.

 Mohsen A. Bakooshli et al, Regeneration of neuromuscular synapses after acute and chronic denervation by inhibiting the gerozyme 15-prostaglandin dehydrogenase, Science Translational Medicine (2023). DOI: 10.1126/scitranslmed.adg1485

Large trial shows taking less blood for lab testing reduces transfusions in intensive care

A world-first clinical trial published in JAMA could provide an easy way to save tens of thousands of units of blood every year worldwide.

The trial, which involved more than 27,000 patients in 25 adult intensive care units (ICUs) across Canada, showed that taking less blood for lab tests using "small-volume" tubes reduced the need for almost one blood transfusion for every 10 patients. Most hospitals use standard tubes that automatically draw four to six milliliters (ml) of blood, but a typical laboratory test requires less than 0.5 ml of blood, meaning the rest (more than 90%) is wasted. Commercially available small-volume tubes have a weaker vacuum inside that automatically draws up to half as much blood. "While the amount of blood drawn per tube is relatively small, ICU patients typically require multiple blood samples taken multiple times every day. This can add up to significant blood loss that contributes to anemia, or low red blood cells. ICU patients are unable to produce more red blood cells to correct for this blood loss and often require treatment with a blood transfusion.

This trial showed that we can save one blood transfusion for every 10 ICU patients by simply switching to small-volume tubes for blood collection.

At a time when everyone is trying to find ways to make health care more sustainable, and preserve our supply of blood products, this study provides a simple solution that can be implemented without additional cost or negative effects. The study also has important implications for patients, as low red blood cells (anemia) can leave patients feeling tired and weak and is associated with can lead to other complications and longer hospital stays. While blood transfusions can usually correct anemia, there can be rare side effects, such as difficulty breathing, allergic reactions and infections.
Part 1

By the numbers

• 97: Percentage of patients who develop anemia after eight days in the ICU
• 50: Percentage of transfusions given in the ICU in the absence of active bleeding
• 41: Amount of blood (in ml) taken per ICU patient per day for routine blood tests (equivalent of one full blood donation every eight days)
• 75: Percentage of patients who receive at least one blood transfusion within seven days of ICU admission (40% of all ICU patients)
• $450: Cost per unit of blood in Canada (not including indirect costs associated with testing, preparation, storage, administration, reactions)
• 90: Percentage of blood that is wasted in routine lab tests
• 10: Units of blood that could be saved per 100 patients with ICU stays of more than 48 hours if the results of this study were implemented

Monkey lives with gene-edited pig kidney A macaque lived for more than two years with a kidney from a gene-edited miniature pig — one of the longest-lasting interspecies organ transplants. It raises hopes that human organ shortages could one day be alleviated by using organs from donor animals. The donor pigs received 69 gene edits to prevent immune reactions after transplantation and to keep the organ healthy. Of the 15 monkeys that received a transplant, five survived for more than one year and one of those lived for 758 days.

https://www.nature.com/articles/s41586-023-06594-4.epdf?sharing_tok...

Hair Turns Gray Due to Stuck Stem Cells

Hair-colouring stem cells must swing back and forth between their maturity states to give hair its colour.

Like human aging, stem cell maturation is considered a one-way process; once an undifferentiated stem cell goes down the path to become a specific type of cell, there is no turning back. But that does not seem to be the case with melanocyte stem cells (McSC), which give rise to cells that produce hair and skin pigments. 

In a recent study, researchers investigated McSC in hair follicles and found that depending on microenvironment cues, McSCs can fluctuate between undifferentiated and differentiated states. The researchers also found that as the hair follicle ages, a larger number of melanocyte stem cells get stuck in an undifferentiated state, losing their ability to mature and produce melanin. Published in Nature, these results not only challenge the traditional view on how stem cells differentiate, but also offer clues to why hair turns gray with aging. 

The researchers were surprised to find that McSC did not reside in an area called the bulge as previously thought, but were instead located in a compartment known as the hair germ. When the hair started to grow, the McSC transitioned to an intermediate differentiation state from which they either transformed into fully mature melanocytes at the base of the growing hair or moved up to the hair bulge where they stayed as undifferentiated cells. Then these stem cells homed back to the hair germ as the hair entered the resting phase of its growth cycle.

Once they realized that the maturation of these cells depended on their location, the team next investigated which signals within those compartments drove these changes. In the new study, the team found that nearby epithelial cells in the hair germ released Wnt ligands that mature the McSC, but these signals were suppressed in the bulge where the cells regained their undifferentiated features.

Melanocytes give hair its color, and hair pigmentation reduces with aging. So, the researchers wondered what would happen to McSC mobility in an aged hair follicle. To accelerate the aging of hair follicles, the researchers plucked mouse hair to induce regeneration of the follicles and observed McSCs over time. In aged mice, they found more of the stem cells in the bulge area rather than going back to the hair germ.

These findings suggested that as the hair follicle ages, McSC get stuck in a region where less pigment-inducing signals are present. This mechanism might explain why hair turns gray much more rapidly than it falls off.

Although scientists knew that cells could swing back and forth between their maturity states when there were tissue injuries, the study results are exciting as they reveal that dedifferentiation can also occur under a physiological condition.

Since the researchers conducted all of the experiments in mice, questions remain as to whether the same events are also seen in humans.

Sun Q, et al. Dedifferentiation maintains melanocyte stem cells in a dynamic niche. Nature. 2023;616(7958):774-782.

Rabbani P, et al. Coordinated activation of Wnt in epithelial and melanocyte stem cel.... Cell. 2011;145(6):941-955.

Research shows wildfire smoke may linger in homes long after initial blaze

Newly published research on indoor air quality  shows wildfire smoke may linger in homes long after the initial blaze has been put out or winds have shifted.

The findings, published in Science Advances, show that wildfire smoke can attach to home surfaces like carpet, drapes or counters—extending the exposure for those inside and potentially causing health problems even after an initial cleaning activity by air purifiers.

However, the research also shows that  surface cleaning—like vacuuming, dusting or mopping—can reduce exposure and limit risk. The team was able to show that the amount of smoke left on surfaces was proportional to the surface area that was cleaned. That means simple cleaning and specifically addressing large but little noticed spaces that may trap harmful compounds such as cabinets and HVAC systems could be beneficial right away.

 Jienan Li et al, The persistence of smoke VOCs indoors: partitioning, surface cleaning, and air cleaning in a smoke-contaminated house, Science Advances (2023). DOI: 10.1126/sciadv.adh8263. www.science.org/doi/10.1126/sciadv.adh8263