How soft sounds might dull pain in mice

Scientists engineer DNA 'receipt book' to store cells' history

New evidence hints at the role of gut microbiota in autistic spectrum disorder

Autism spectrum disorder (ASD) is a neurological and developmental condition that affects how humans communicate, learn new things and behave. Symptoms of ASD can include difficulties in interacting with others and adapting to changes in routine, repetitive behaviors, irritability and restricted or fixated interests for specific things.

While symptoms of autism can emerge at any age, the first signs generally start to show within the first two years of a child's life. People with ASD can encounter numerous challenges, which can be addressed through support services, talk therapy and sometimes medication.

To this day, neuroscientists and medical researchers have not identified the primary causes of ASD. Nonetheless, past findings suggest that it could be caused by the interaction of specific genes with environmental factors.

Interestingly, recent neuroscience studies have found that the biological makeup of the gut could contribute to some of the most characteristic symptoms of ASD. More specifically, experiments on mice suggest that the pathway between gut bacteria  and the central nervous system can affect social behaviors.

Building on previous findings, researchers at University of Rome 'Tor Vergata' and University of Calabria have recently carried out a new study on mice, investigating the effects of transplanting fecal microbiota gathered from autistic donors to mice. Their results, published in Neuroscience, provide further evidence that links gut microbiota with social behaviors typical of ASD.

Scientists examined two different groups of mice. Mice in the first group (i.e., the experimental group) received transplanted microbiota originating from the gut of children with ASD, while mice in the other (i.e., the control group) were exposed to VPA, a synthetic compound with anticonvulsant properties, while in their mothers' wounds.

Contextually, FMT accounted for elevated expression levels of the pro-inflammatory factors IL-1β, IL-6, COX-1 and TNF-α in both brain and small intestine.

observed that the mice who received the ASD microbiota exhibited unusual behaviors while completing different maze tests that are widely used in neuroscience studies. Their behaviors could be linked to those observed in children and adults with ASD.

The recent findings gathered by this team of researchers seem to confirm previous results in the field, suggesting that gut microbiota can indeed play a role in social behaviors. In the future, they could inspire new research in this area and contribute to the testing and gradual introduction of treatments for autism that also consider diet and gut health.

Modifications of behavior and inflammation in mice following transplant with fecal microbiota from children with autism. Neuroscience(2022). DOI: 10.1016/j.neuroscience.2022.06.038.

Why people struggle to recognise the faces of people from different racial backgrounds

Cognitive psychologists think they have discovered the answer to a 60-year-old question as to why people find it more difficult to recognize faces from visually distinct racial backgrounds than they do their own.

This phenomenon named the other-race effect (ORE) was first discovered in the 1960s and has consistently been demonstrated through the face inversion effect (FIE) paradigm, where people are tested with pictures of faces presented in their usual upright orientation and inverted upside down. Such experiments have consistently shown that the FIE is larger when individuals are presented with faces from their own race as opposed to other race faces. It has prompted decades of debate as to the underlying factors, with social scientists historically taking the view that it's indicative of how people are less motivated to engage and differentiate members of other races, thus leading to a weaker memory for them. Cognitive scientists, on the other hand, propose that it is based on the comparative lack of visual experience that people have with other-race individuals, which then results in reduced perceptual expertise with other-race faces. Now, a team in the Department of Psychology at Exeter, using direct electrical current brain stimulation, has found that the ORE would appear to be caused by a lack of cognitive visual expertise and not by social bias.

Published in the journal Scientific Reports, the research was conducted at Exeter's Washington Singer Laboratories, and used a non-invasive transcraniaL direct current stimulation (tDCS) procedure, specifically formulated to impair a person's ability to recognize upright faces. This was applied to the participants' dorsolateral prefrontal cortex, via a pair of sponges attached to their scalp.

Ciro Civile et al, Transcranial direct current stimulation (tDCS) eliminates the other-race effect (ORE) indexed by the face inversion effect for own versus other-race faces, Scientific Reports (2022). DOI: 10.1038/s41598-022-17294-w

Phantom vibration syndrome

Scientists reveal how detergents actually work
Scientists have discovered the precise way detergents break biological membranes, which could increase our understanding of how soaps work to kill viruses like COVID-19.
Detergents play a role in everyday life, from removing tough stains and cleaning messy hands to fixing sticky locks. On the nanoscale, they are extremely destructive, and only a few droplets in water can rupture and kill living organisms. This property has led to their widespread use and many soap formulations have been developed to kill disease-carrying viruses, including COVID-19.
Understanding the precise molecular-level mechanisms through which detergents work may help us better design antiviral agents that can combat disease at the earliest possible stage.
For the study, the scientists looked at the detergent Tween-20, which is a key protective ingredient in many products such as handwashes.Detergent molecules like Tween-20 are shaped like an ice cream cone. At the top of the cone is a region that interacts strongly with water, and at the bottom a group of atoms repel water and form a pointed tail. When you wash your hands with soap, an army of detergent molecules surround the bacteria and viruses on your skin, and in an attempt to escape the surrounding water, they scurry towards and bombard them, tails first, squeezing their membrane envelopes and breaking them apart.The chemical properties of detergents have been studied in detail, but until now the precise, molecular level details of the interaction have been difficult to assess because of a lack of tools and techniques capable of capturing the entire process.Researchers  have now developed a series of methods to try and learn more about these important interactions. They  created a series of highly-controllable membrane balls, and they used a molecular nanoruler known as single-molecule FRET (fluorescence resonance energy transfer), to measure how constituents of the membranes move apart during their interaction with detergents.They discovered that after Tween-20 binds to the membranes, the balls expand significantly and pores form on their surface before they completely fragment.To confirm their findings, the researchers used computer simulations to model how the membranes evolved.The experimental results from different approaches matched up extremely well, and the molecular dynamics simulations allowed scientists to extract otherwise hidden physics governing the process.
Lara Dresser et al, Tween-20 Induces the Structural Remodeling of Single Lipid Vesicles, The Journal of Physical Chemistry Letters (2022). DOI: 10.1021/acs.jpclett.2c00704

Researchers discover one of the largest known bacteria-to-animal gene transfers inside a fruit flyA fruit fly genome is not just made up of fruit fly DNA—at least for one fruit fly species. New research shows that one fruit fly species contains whole genomes of a kind of bacteria, making this finding the largest bacteria-to-animal transfer of genetic material ever discovered. The new research also sheds light on how this happens.
Scientists used new genetic long-read sequencing technology to show how genes from the bacteria Wolbachia incorporated themselves into the fly genome up to 8,000 years ago.The researchers say their findings show that unlike Darwin's finches or Mendel's peas, genetic variation isn't always small, incremental, and predictable.In addition to the long reads, the researchers validated junctions between integrated bacteria genes and the host fruit fly genome. To determine if the bacteria genes were functional and not just DNA fossils, the researchers sequenced the RNA from fruit flies specifically looking for copies of RNA that were created from templates of the inserted bacterial DNA. They showed the bacteria genes were encoded into RNA and were edited and rearranged into newly modified sequences indicating that the genetic material is functional.
An analysis of the unique sequences revealed that the bacteria DNA integrated into the fruit fly genome in the last 8,000 years—exclusively within chromosome 4—expanding the chromosome size by making up about 20 percent of chromosome 4. Whole bacterial genome integration supports a DNA-based rather than an RNA-based mechanism of integration.
They also found nearly a complete second genome and much more with almost 10 copies of some bacterial genome regions.
Wolbachia is an intracellular bacteria that infects numerous types of insects. Wolbachia transmits its genes maternally through female egg cells. Some research has showed that these infections are more mutualistic than parasitic, giving insects advantages, such as resistance to certain viruses.

Eric S. Tvedte et al, Accumulation of endosymbiont genomes in an insect autosome followed by endosymbiont replacement, Current Biology (2022). DOI: 10.1016/j.cub.2022.05.024

Salt in sea spray found to be the reason for less lightning over tropical oceans

Novel Antibiotic kills bacteria via a new two-step mechanism

 Bioscientists use mixed-reality headset, custom software to measure vegetation in the field

How the genome is packed into chromosomes that can be faithfully moved during cell division

Researchers discovered a molecular mechanism that confers special physical properties to chromosomes in dividing human cells to enable their faithful transport to the progeny. They showed how a chemical modification establishes a sharp surface boundary on chromosomes, thus allowing them to resist perforation by microtubules of the spindle apparatus. The findings are published in the journal Nature.

When cells divide, they need to transport exactly one genome copy to each of the two daughter cells. Faithful genome segregation requires the packaging of extremely long chromosomal DNA molecules into discrete bodies so that they can be efficiently moved by the mitotic spindle, a filament system composed of thousands of microtubules. The new findings shed light on how mitotic chromosomes resist the constant pushing and pulling forces generated by the microtubules. Amidst this complex system, the distinct physical properties are conferred to the chromosomes by changing the levels of histone acetylation, a chemical modification within the chromatin fiber.
Prior work had shown that, in dividing cells, the chromatin fibers are folded into loops by a large protein complex called condensin. However, the role of condensin alone could not explain why chromosomes appear as dense bodies with a sharp surface rather than a loose structure resembling a bottlebrush. Some studies had suggested a role of histone acetylation in regulating the level of compaction during cell division, but the interplay of histone acetylation with condensin and its functional relevance remained unclear. This new work is now able to conceptually disentangle the two mechanisms.
The team varied the levels of condensin and histone acetylation to study their precise effects. Removing condensin disrupted the elongated shape of chromosomes in dividing cells and lowered their resistance to pulling forces but did not affect their level of compaction. Combining condensin depletion with a treatment that increases the levels of histone acetylation caused massive chromatin decompaction in dividing cells, and perforation of chromosomes by microtubules.

The researchers hypothesized that chromatin is organized as a swollen gel throughout most of the cell cycle (when it is relatively highly acetylated) and that this gel compacts to an insoluble form during cell division when the acetylation levels globally decrease. They then developed an assay to probe the solubility of chromatin by fragmenting mitotic chromosomes into small pieces. The fragments of mitotic chromosomes formed droplets of liquid chromatin, but when the acetylation level was increased, the chromatin fragments dissolved in the cytoplasm. These observations support a model where a global reduction of chromatin acetylation during mitosis establishes an immiscible chromatin gel with a sharp phase boundary, providing a physical basis for resistance against microtubule perforation.
With further experiments involving pure chromatin that was reconstituted in vitro, and by probing chromatin access by various soluble macromolecules, the team found that immiscible chromatin forms a structure dense in negative charge that excludes negatively charged macromolecules and microtubules. This study shows how DNA looping by the condensin complex cooperates with a chromatin phase separation process to build mitotic chromosomes that resist both pulling and pushing forces exerted by the spindle. The deacetylation of histones during cell division hence confers unique physical properties to chromosomes that are required for their faithful segregation.
Daniel Gerlich, A mitotic chromatin phase transition prevents perforation by microtubules, Nature (2022). DOI: 10.1038/s41586-022-05027-y. www.nature.com/articles/s41586-022-05027-y

Sterile mice produce rat sperm

Researchers generated rat sperm cells inside sterile mice using a technique called blastocyst complementation. The advance appears August 4 in the journal Stem Cell Reports.
This new study shows that scientists can use sterile animals as hosts for the generation of germ cells from other animal species.
Aside from a conceptual advancement, this notion can be utilized to produce endangered animal species gametes inside more prevalent animals. Other implications may involve an improved method to produce rat transgenic models for biomedical research.
Pluripotent stem cells (PSCs) provide a powerful tool for biomedical research, but the generation of gametes in the form of eggs or sperm cells from PSCs is a highly challenging endeavor. In prior studies, researchers used a technique called blastocyst complementation to generate rat organs in mice using PSCs and mutated mouse embryos that cannot produce specific organs. Building on this work, Bar-Nur and his collaborators wondered whether it would be possible to generate rat sperm inside mice that carry a genetic mutation that otherwise renders them sterile.

To test this idea, the researchers injected rat PSCs into mouse embryos to produce mouse-rat chimeras. An essential gene for sperm production was mutated in the mouse blastocysts. The rat stem cells developed together with the mouse cells, thereby generating a chimeric animal composed of genotypes from the two species. As a consequence of the genetic sterility-inducing mutation, an empty niche developed inside the testes, which enabled the rat cells to colonize them and exclusively generate rat sperm in mouse-rat chimeras. The sperm cells could fertilize rat egg cells, but the embryos did not develop normally or give rise to live offspring.

The interesting thing observed in this study was that all the sperm cells inside the chimeras were of rat origin. As such, the mouse host environment, which was sterile due to a genetic mutation, was still able to support efficient sperm cell production from a different animal species.

Although the researchers were able to generate rat sperm cells that morphologically appeared indistinguishable from normal rat sperm cells, these cells were immotile and the fertilization rates of rat eggs was significantly lower in comparison to rat sperm cells produced in rats. Nonetheless, the work provides a proof-of-principle that one can generate sperm cells of one animal species in another by mixing the two species in an artificially generated organism called a chimera. Using sterile mice for genetically modified rat PSCs may speed up the production of transgenic rats to model human diseases in biomedical research.

Ori Bar-Nur, Exclusive generation of rat spermatozoa in sterile mice utilizing blastocyst complementation with pluripotent stem cells, Stem Cell Reports (2022). DOI: 10.1016/j.stemcr.2022.07.005. www.cell.com/stem-cell-reports … 2213-6711(22)00364-2

Early-life acquisition of antimicrobial resistance in newborn children from low- and middle-income countries
Every year, almost 7 million potentially serious bacterial infections are estimated to occur in newborns, resulting in more than 550,000 annual neonatal deaths. Most of these infections and deaths happen in LMICs, where often scarce resources can limit the capacity to diagnose and treat sepsis. These problems are further complicated by the global rise of antimicrobial resistance (AMR), particularly the rapid spread of gram-negative bacteria that are resistant to antibiotics—including Klebsiella pneumoniae, Escherichia coli, and Enterobacter cloacae that are no longer susceptible to ß-lactam antibiotics, such as ampicillin and ceftazidime. AMR is already estimated to account for approximately 5 million deaths a year worldwide, and has been predicted to result in 10 million annual deaths by 2050.
Despite neonatal sepsis representing such a major health problem in LMICs, it is still unclear how, when, and where newborn babies acquire life-threatening infections. Furthermore, the factors associated with the presence of AMR in these cases are also still being elucidated. For example, there have been no studies in LMICs examining whether the presence of antibiotic-resistant bacteria in mothers is linked to the development of sepsis in their newborns.

In a new study published in Nature Microbiology, scientists decided to look at the presence of antibiotic resistance genes (ARGs) in the gut microbiota—the collection of microbes that are present in the human gut—of mothers and their babies from 7 LMICs in Africa and South Asia. As part of the "Burden of Antibiotic Resistance in Neonates from Developing Societies" study, or BARNARDS—a network of 12 clinical sites across Bangladesh, Ethiopia, India, Nigeria, Pakistan, Rwanda and South Africa—they recruited 35,040 mothers and 36,285 neonates. From these, they collected 18,148 rectal swabs (15,217 from mothers and 2,931 from neonates, including 626 with sepsis), which were used to grow the bacteria present in these samples and assess the presence of clinically important ARGs in the microbiota of mothers and their babies. The authors found that a large number of samples carried genes linked to antibiotic resistance, suggesting that AMR is far more widespread in these settings than previously anticipated.

For example, samples from around 1 in 5 neonates (18.5%) were positive for blaNDM, a gene that encodes New Delhi metallo-beta-lactamase, which is an enzyme that can destroy ß-lactam antibiotics including the commonly used carbapenems, resulting in the bacteria being resistant against this drug. Importantly, the researchers found that ARGs were present in neonates within hours of birth, indicating that initial colonization of the newborns with antibiotic-resistant bacteria occurred at birth or soon after, likely through contact with the mother or from the hospital environment.

Maria Carvalho, Antibiotic resistance genes in the gut microbiota of mothers and linked neonates with or without sepsis from low- and middle-income countries, Nature Microbiology (2022). DOI: 10.1038/s41564-022-01184-y. www.nature.com/articles/s41564-022-01184-y

Israeli scientists create the world's first 'Artificial Embryos' 

Robotic motion in curved space defies standard laws of physics

When humans, animals, and machines move throughout the world, they always push against something, whether it's the ground, air, or water. Until recently, physicists thought this to be a constant, following the law of conservation momentum. Now, researchers have proven the opposite—when bodies exist in curved spaces, it turns out that they can in fact move without pushing against something.

The findings were published in Proceedings of the National Academy of Sciences on July 28, 2022. In the paper, a team of researchers created a robot confined to a spherical surface with unprecedented levels of isolation from its environment, so that these curvature-induced effects would predominate.

The researchers found that as the robot changed its shape, it inched forward around the sphere in a way that could not be attributed to environmental interactions.

The researchers set out to study how an object moved within a curved space. To confine the object on the sphere with minimal interaction or exchange of momentum with the environment in the curved space, they let a set of motors drive on curved tracks as moving masses. They then connected this system holistically to a rotating shaft so that the motors always move on a sphere. The shaft was supported by air bearings and bushings to minimize the friction, and the alignment of the shaft was adjusted with the Earth's gravity to minimize the residual force of gravity.

From there, as the robot continued to move, gravity and friction exerted slight forces on it. These forces hybridized with the curvature effects to produce a strange dynamic with properties neither could induce on their own. The research provides an important demonstration of how curved spaces can be attained and how it fundamentally challenges physical laws and intuition designed for flat space. 

While the effects are small, as robotics becomes increasingly precise, understanding this curvature-induced effect may be of practical importance, just as the slight frequency shift induced by gravity became crucial to allow GPS systems to accurately convey their positions to orbital satellites. Ultimately, the principles of how a space's curvature can be harnessed for locomotion may allow spacecraft to navigate the highly curved space around a black hole.

Also because spacetime is very slightly curved, a device could actually move forward without any external forces or emitting a propellant—a novel discovery.

Shengkai Li et al, Robotic swimming in curved space via geometric phase, Proceedings of the National Academy of Sciences (2022). DOI: 10.1073/pnas.2200924119

Dry lightning is cloud-to-ground (CG) lightning without any accompanied rainfall nearby.

Dry lightning sparks some of the most destructive and costly wildfires in California, study finds

A new study has found dry lightning outbreaks are the leading cause of some of the largest wildfire outbreaks in modern California history.

Researchers have developed the first long-term climatology of dry lightning—lightning which occurs with less than 2.5 mm of rainfall.

They found that moisture and instability high in the atmosphere—above a hot, dry, lower atmosphere—were key drivers of dry lightning across all regions in central and northern California and that widespread dry lightning outbreaks can occur anytime between May–October, even in "quiet" years for lightning activity.

Meteorological and geographical factors associated with dry lightning in central and northern California, Environmental Research: Climate (2022) DOI: 10.1088/2752-5295/ac84a0

https://phys.org/news/2022-08-lightning-destructive-costly-wildfire...

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Chances of climate catastrophe are ignored, scientists say

Experts are ignoring the worst possible climate change catastrophic scenarios, including collapse of society or the potential extinction of humans, however unlikely, a group of top scientists claim.

Eleven scientists from around the world are calling on the United Nations' Intergovernmental Panel on Climate Change, the world's authoritative climate science organization, to do a special science report on "catastrophic climate change" to "bring into focus how much is at stake in a worst-case scenario." In their perspective piece in Monday's Proceedings of the National Academy of Sciences they raise the idea of human extinction and worldwide societal collapse in the third sentence, calling it "a dangerously underexplored topic."

The scientists said they aren't saying that worst is going to happen. They say the trouble is no one knows how likely or unlikely a "climate endgame" is and the world needs those calculations to battle global warming.

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Mystery cells that create blood stem cells in mammals identified

Imagine if one day blood transfusions from strangers were not needed because they could be produced from cells that line your own blood vessels' cells.

While that day is still some years off, medical researchers at UNSW Sydney have made an important first step by identifying—in mice—a mechanism that is used naturally in mammals to make blood from cells that line blood vessels.

It was already known that a process termed "endothelial to hematopoietic transition" takes place in mammalian embryos, whereby cells lining blood vessels (endothelial cells) change into blood stem cells.

But the identity of the cells that regulate this process had up until now been a mystery.

In a paper published recently in the journal Nature Cell Biology, a team of researchers describe how they solved this puzzle by identifying the cells in the embryo that can convert adult endothelial cells into blood stem cells. The cells—known as "Mesp1-derived PDGFRA+ stromal cells"—reside underneath the aorta.

While more research is needed before this can be translated into clinical practice, the discovery could be an important step in regenerative medicine by providing a potential new tool to generate engraftable hematopoietic stem cells.

Vashe Chandrakanthan et al, Mesoderm-derived PDGFRA+ cells regulate the emergence of hematopoietic stem cells in the dorsal aorta, Nature Cell Biology (2022). DOI: 10.1038/s41556-022-00955-3

Watch tiny electromechanical robots that are faster than cheetahs for their size

Methane satellites find landfills with the same climate impact as several hundred thousand cars

Methane is almost thirty times more powerful as a greenhouse gas than CO₂. Researchers from SRON Netherlands Institute for Space Research therefore scan the entire globe for large methane leaks. A landfill in Buenos Aires turns out to emit tens of tons of methane per hour, comparable to the climate impact of one and a half million cars. They also detect large emissions from landfills in India and Pakistan, identifying new low-hanging fruit in the battle against climate change. The work was published on August 10 in Science Advances.

Methane is the second largest anthropogenic contributor to the greenhouse effect, after CO₂. This is due to its large global warming potential over 100 years (GWP-100). Methane is almost 30 times more potent per ton as a greenhouse gas than CO₂. When methane is released through human activity—by oil installations, coal mines, cattle sheds or landfills—it can be made less harmful by flaring it and thereby converting it to CO₂. Even better, if you capture it, you can put it to good use in boilers or stoves. Researchers from SRON Netherlands Institute for Space Research have now used satellite data to locate a number of landfills that are low-hanging fruit in the fight against climate change. Four landfills in Argentina, India and Pakistan emit several or even tens of tons of methane per hour.

 Buenos Aires, Delhi, Lahore and Mumbai stood out, with urban emissions on average twice as high as estimated in global inventories. The landfill in Buenos Aires emits 28 tons of methane per hour, comparable to the climate impact of 1.5 million cars. The three other landfills are responsible for, respectively, three, six and 10 tons of methane per hour, which still amounts to the impact of 130,000 to 500,000 cars.

Methane is odorless and colorless, so leaks are notoriously difficult to detect. But satellites are ideally suited for this. Landfills are super-emitters that pump large amounts of methane into the atmosphere. That is painful to watch because you can solve it with relatively little effort. You could, for example, separate and compost the organic waste, which would drastically reduce methane production. And even in the case of mixed waste, you can still collect or flare the methane produced. Methane has a lifetime of only about 10 years in the atmosphere, so if we act now, we will quickly see results in the form of less global warming.

Joannes D. Maasakkers, Daniel J. Varon, Aldís Elfarsdóttir, Jason McKeever, Dylan Jervis, Gourav Mahapatra, Sudhanshu Pandey, Alba Lorente, Tobias Borsdorff, Lodewijck R. Foorthuis, Berend J. Schuit, Paul Tol, Tim A. van Kempen, Richard van Hees, Ilse Aben, 'Using satellites to uncover large methane emissions from landfills', Science Advances, 2022. science.org/doi/10.1126/sciadv.abn9683

Rainwater unsafe to drink due to chemicals: study

Rainwater everywhere on the planet is unsafe to drink due to levels of toxic chemicals known as PFAS that exceed the latest guidelines, according to a new study by scientists.

Commonly known as 'forever chemicals' because they disintegrate extremely slowly, PFAS (per- and polyfluoroalkyl substances) were initially found in packaging, shampoo or makeup but have spread to our entire environment, including water and air.

There is nowhere on Earth where the rain would be safe to drink, according to the measurements that scientists have taken now.

Even in Antarctica or the Tibetan plateau, the levels in the rainwater are above the drinking water guidelines that the US EPA (Environmental Protection Agency) proposed.

According to some studies, exposure can also lead to problems with fertility, development delays in children, increased risks of obesity or certain cancers (prostate, kidney and testicular), an increase in cholesterol levels.
—Planet 'irreversibly contaminated'—

We have made the planet inhospitable to human life by irreversibly contaminating it now so that nothing is clean anymore. And to the point that's it's not clean enough to be safe.

We have crossed a planetary boundary. And we have to learn to live with it.

 Per- and polyfluoroalkyl substances (PFAS) define a new planetary boundary for novel entities that has been exceeded, Environmental Science & Technology (2022). DOI: 10.1021/acs.est.2c02765

Study of OTC supplements shows some have very high levels of levodopa, which can lead to paranoia

A team of researchers  has found that over-the-counter supplements that are advertised as containing extracts from Mucuna pruriens, a type of bean that contains levodopa, sometimes contain high levels of levodopa. In their paper published in the journal JAMA Neurology, the group describes testing the levels of levodopa in several Mucuna pruriens–based supplements.

Levodopa (known more commonly as L-DOPA) is a type of amino acid that is commonly found in plants and animals. In humans, it serves as a precursor to several types of neurotransmitters, one of which is dopamine. In 1969, researchers discovered that giving L-DOPA to patients with Parkinson's disease could reduce their symptoms; therefore, it is widely used today. Prior research has also found that many patients with Parkinson's disease believe that higher doses of L-DOPA will further improve their condition, but doctors do not agree. Still, some people with the disease buy over-the-counter supplements containing Mucuna pruriens extracts because research has shown the beans contain L-DOPA. In addition to overriding established medical advice, taking such supplements can have negative effects on patients, such as the development of paranoia. In this new effort, the researchers sought to learn more about Mucuna pruriens supplements—specifically, the amount of levodopa they contain. They purchased 16 bottles of the supplements and tested them. They found that the supplements all had different amounts of levodopa and that the amounts did not match what were listed on the labels. They also found some of the supplements had more levodopa in them than prescription medications. The researchers suggest their findings should be a warning to Parkinson's patients—they have no way of knowing how much levodopa they are consuming if they take such supplements, which can wreak havoc with the treatment prescribed by their doctor. The researchers note that some people who do not have Parkinson's disease also purchase and consume the supplements, which can lead to paranoia, agitation, impulse control and sometimes psychosis. 

Pieter A. Cohen et al, Levodopa Content of Mucuna pruriens Supplements in the NIH Dietary Supplement Label Database, JAMA Neurology (2022). DOI: 10.1001/jamaneurol.2022.2184

Bioengineered cornea restores sight to the blind and visually impaired

Researchers and entrepreneurs have developed an implant made of collagen protein from pig's skin, which resembles the human cornea. In a pilot study, the implant restored vision to 20 people with diseased corneas, most of whom were blind prior to receiving the implant. The study has been published in Nature Biotechnology. The promising results bring hope to those suffering from corneal blindness and low vision by providing a bioengineered implant as an alternative to the transplantation of donated human corneas, which are scarce in countries where the need for them is greatest.

The results show that it is possible to develop a biomaterial that meets all the criteria for being used as human implants, which can be mass-produced and stored up to two years and thereby reach even more people with vision problems. This gets us around the problem of shortage of donated corneal tissue and access to other treatments for eye diseases.

The cornea consists mainly of the protein collagen. To create an alternative to human cornea, the researchers used collagen molecules derived from pig skin that were highly purified and produced under strict conditions for human use. The pig skin used is a byproduct of the food industry, making it easy to access and economically advantageous. In the process of constructing the implant, the researchers stabilized the loose collagen molecules forming a robust and transparent material that could withstand handling and implantation in the eye. While donated corneas must be used within two weeks, the bioengineered corneas can be stored for up to two years before use.

 Mehrdad Rafat, Bioengineered corneal tissue for minimally invasive vision restoration in advanced keratoconus in two clinical cohorts, Nature Biotechnology (2022). DOI: 10.1038/s41587-022-01408-w. www.nature.com/articles/s41587-022-01408-w

Nanoparticles train immune cells to fight cancer

Scientists in the department of Advanced Organ Bioengineering and Therapeutics (Faculty of S&T, TechMed Centre) recently published a novel cancer immune therapy in the scientific journal Nature Communications. In their research, scientists developed newly designed nanoparticles which can target the body's immune cells to turn them against cancer.

In cancer research, it has been increasingly known that tumor cells can change the alliance of some specific macrophages to help the tumor grow. "Macrophages are cells that act like the vacuum cleaners of your immune system. Normally they catch intruders and destroy them, but tumor cells can hijack these cells to help them spread throughout the body.

Scientists now designed nanoparticles that train these tumor-supporting "bad" macrophages into cells that will fight tumors. However, these tiny (100–200 nanometer diameter) cell-like structures first have to find the macrophages before they can start the training. 

To solve this challenge, the researchers had to alter the nanoparticles. The nanoparticles consist of a double layer of specific lipids (phospholipids) called nanoliposomes. These lipids have long tails that like to stick together in between the double layer. Researchers replaced some of the lipids to ones with a slightly shorter charged tail that can 'flip' to the outer surface. The bad macrophages can recognize these flipped tails and then eat up the whole particle.

When scientists knew how to target the bad macrophages, it became time to train them into fighting the tumor again. The researchers added a small component of the bacterial cell wall, which can train macrophages, to the "tail-flipping" nanoliposomes in the double layer wall of these nanoparticles. These molecules are then also taken up by the bad macrophages which subsequently train them to kill cancer cells. Targeting this compound this way prevents it from being recognized by the wrong cells and thus prevents damage to other parts of the body.

In the publication, the researchers not only show that the hijacked macrophages can be retrained to fight the cancer cells again, inhibiting the tumor growth by 70% in breast tumor mouse models. In the mice, the therapy prevented metastasis, the ability of cancer cells to spread through the body. The trained macrophages prevented the tumor cells from "preparing" lung tissue to host tumor cells—a process before metastasis. When a tumor cell arrived in the lungs, the tissue wasn't ready and the tumor cell couldn't start a new tumor.

 Praneeth R. Kuninty et al, Cancer immune therapy using engineered 'tail-flipping' nanoliposomes targeting alternatively activated macrophages, Nature Communications (2022). DOI: 10.1038/s41467-022-32091-9

Climate change and extreme heat are making us more anxious

Globally, heat waves have become an increasingly frequent summer affair, as much of the world faces extremely high temperatures. The rising frequency and intensity of heat waves can trigger various forms of emotional distress affecting people's mental health. One such emerging form of distress is eco-anxiety, which is defined by the American Psychological Association as the chronic fear of environmental doom that comes from observing climate change. In other words, people are worried about what a changing planet means for them and future generations. According to a landmark survey on eco-anxiety, 68% of adults reported experiencing "at least a little eco-anxiety" and 48% of young people report that climate change negatively affects their daily life and functioning. These worries are normal and even rational. We are connected to the land, air and water around us. So when our environments change, a primal sadness and worry is perfectly appropriate and perhaps even advantageous for survival. For millennia, people have relied on their ability to monitor, adapt to and migrate within their environment in order to survive. However, what we're facing with climate change is a whole new level of change. As highlighted by last year's IPCC report, the evidence showing that climate change causes greater frequency and intensity of extreme heat events is more certain than any other documented effect of climate change. Unfortunately, the same report predicts that global temperatures will continue to rise and their effects will worsen. It remains unclear what treatments and prevention strategies for eco-anxiety may be most effective, as public health and therapeutic research in this area is an emerging field. However, one thing is for certain: none of us can fix climate change, at least not alone. Climate change is a collective problem, not an individual one. Mitigating and adapting to it will require investments to build happier and healthier communities that will ensure that during extreme heat and other weather events people are not left to fend for themselves.

https://theconversation.com/climate-change-and-extreme-heat-are-mak...

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Matter at extreme conditions of very high temperature and pressure turns out to be remarkably simple and universal

Scientists at Queen Mary University of London have made two discoveries about the behavior of "supercritical matter"—matter at the critical point where the differences between liquids and gases seemingly disappear.
While the behavior of matter at reasonably low temperature and pressure was well understood, the picture of matter at high temperature and pressure was blurred. Above the critical point, differences between liquids and gases seemingly disappear, and the supercritical matter was thought to become hot, dense and homogeneous.

The researchers believed there was new physics yet to be uncovered about this matter at the supercritical state.

By applying two parameters—the heat capacity and the length over which waves can propagate in the system, they made two key discoveries. First, they found that there is a fixed inversion point between the two where matter changes its physical properties—from liquid-like to gas-like. They also found that this inversion point is remarkably close in all systems studied, telling us that the supercritical matter is intriguingly simple and amenable to new understanding.

As well as fundamental understanding of the states of matter and the phase transition diagram, understanding supercritical matter has many practical applications; hydrogen and helium are supercritical in gas giant planets such as Jupiter and Saturn, and therefore govern their physical properties. In green environmental applications, supercritical fluids have also proved to be very efficient at destroying hazardous wastes, but engineers increasingly want guidance from theory in order to improve efficiency of supercritical processes.

The asserted universality of the supercritical matter opens a way to a new physically transparent picture of matter at extreme conditions. This is an exciting prospect from the point of view of fundamental physics as well as understanding and predicting supercritical properties in green environmental applications, astronomy and other areas.

C. Cockrell et al, Double universality of the transition in the supercritical state, Science Advances (2022). DOI: 10.1126/sciadv.abq5183. www.science.org/doi/10.1126/sciadv.abq5183

Weird and wonderful world of fungi shaped by evolutionary bursts, study finds

Scientists  have discovered that the vast anatomical variety of fungi stems from evolutionary increases in multicellular complexity.

Most people recognize that fungi come in an assortment of shapes and sizes.

We didn't know till now how this variety was distributed across the different types of fungi. Which groups are the most varied when considering all parts of the fungal body plan? Which are the least? How has this variety accumulated and diminished through time? What has shaped these patterns in disparity?

What scientists now found  was that fungal disparity has evolved episodically through time, and that the evolution of multicellularity in different fungi appears to open the door for greater morphological variety. They saw increases in disparity associated with both the emergence of the first multicellular fungi, and then the evolution of complex fruiting bodies such as mushrooms and saddles in dikaryotic species. These fungi are defined by the inclusion of a dikaryon, a cell with two separate nuclei, in their life cycles.

The main implication is that these results align with those of analyses of animal disparity. Both kingdoms present clumpy distributions of anatomical variety which have evolved intermittently through time.

The world of fungi is defined by bright colors, strange shapes, and stranger anatomies. This study analyses demonstrate that this breath-taking anatomical variety has evolved in bursts, driven by evolutionary increases in multicellular complexity.

Thomas Smith, Evolution of fungal phenotypic disparity, Nature Ecology & Evolution (2022). DOI: 10.1038/s41559-022-01844-6. www.nature.com/articles/s41559-022-01844-6

Nuclear war would cause a global famine and kill billions, study finds

More than 5 billion people would die of hunger following a full-scale nuclear war between the U.S. and Russia, according to a global study led by Rutgers climate scientists that estimates post-conflict crop production.

Building on past research, researchers now worked to calculate how much sun-blocking soot would enter the atmosphere from firestorms that would be ignited by the detonation of nuclear weapons. Researchers calculated soot dispersal from six war scenarios—five smaller India-Pakistan wars and a large U.S.-Russia war—based on the size of each country's nuclear arsenal.

These data then were entered into the Community Earth System Model, a climate forecasting tool supported by the National Center for Atmospheric Research (NCAR). The NCAR Community Land Model made it possible to estimate productivity of major crops (maize, rice, spring wheat and soybean) on a country-by-country basis. The researchers also examined projected changes to livestock pasture and in global marine fisheries.

Under even the smallest nuclear scenario, a localized war between India and Pakistan, global average caloric production decreased 7% within five years of the conflict. In the largest war scenario tested—a full-scale U.S.-Russia nuclear conflict—global average caloric production decreased by about 90% three to four years after the fighting.

Crop declines would be the most severe in the mid-high latitude nations, including major exporting countries such as Russia and the U.S., which could trigger export restrictions and cause severe disruptions in import-dependent countries in Africa and the Middle East.

These changes would induce a catastrophic disruption of global food markets, the researchers conclude. Even a 7% global decline in crop yield would exceed the largest anomaly ever recorded since the beginning of Food and Agricultural Organization observational records in 1961. Under the largest war scenario, more than 75% of the planet would be starving within two years.

Researchers considered whether using crops fed to livestock as human food or reducing food waste could offset caloric losses in a war's immediate aftermath, but the savings were minimal under the large injection scenarios.

Moreover, the ozone layer would be destroyed by the heating of the stratosphere, producing more ultraviolet radiation at the surface, and we need to understand that impact on food supplies too.

The data tell us one thing: We must prevent a nuclear war from ever happening.

Lili Xia, Global food insecurity and famine from reduced crop, marine fishery and livestock production due to climate disruption from nuclear war soot injection, Nature Food (2022). DOI: 10.1038/s43016-022-00573-0. www.nature.com/articles/s43016-022-00573-0

Potential anti-aging components of Moringa oleifera leaf

Moringa oleifera Lam., also known as drum stick and Miracle Tree, primarily derived from India, is now widely distributed in tropical and subtropical regions. Previous studies have showed that M. oleifera has anti-aging effects, but there is a lack of in-depth research on the specific active ingredients and mechanisms of this anti-aging activity. Researchers are working to screen out the most effective active components of M. oleifera leaves.

Scientists in China conducted in vitro elastase and collagenase enzyme inhibitory assays to evaluate the activities of M. oleifera leaf extracts.

They found that M. oleifera leaf extracts possessed promising anti-elastase and anti-collagenase activities. Then, 10, 8, and 14 potential bioactive phytochemicals were screened out from M. oleifera leaf extracts against elastase, collagenase and hyaluronidase using the multi-target bio-affinity ultrafiltration coupled to high-performance liquid chromatography-mass spectrometry (AUF-HPLC-MS), respectively. In addition, further verification of representative active components was completed with molecular docking analysis. Results showed that these potentially active compounds could form hydrogen bonds with amino acid residues Asn112, Trp115, Glu141, Glu164, and Asp221 of elastase, Arg214, Val215, Glu219, and Pro238 of collagenase, Arg47, Asp56, Gly58, Asp111, Glu113, and Ser304 of hyaluronidase, respectively. These hydrogen bonds enhanced the binding ability of active small molecules to biological target molecules. This is the first study to comprehensively demonstrate M. oleifera leaves possess the significant elastase and collagenase inhibitory activities in vitro and reveal its potential bioactive components as well as the mechanism of anti-aging activity.

This work provides a theoretical basis for its further development into functional anti-aging products in the cosmetics and cosmeceutical industries combating aging and skin wrinkling.

Yongbing Xu et al, Potential Anti-aging Components From Moringa oleifera Leaves Explored by Affinity Ultrafiltration With Multiple Drug Targets, Frontiers in Nutrition (2022). DOI: 10.3389/fnut.2022.854882

The entanglement of two quantum memory systems 12.5 km apart from each other

Quantum computing technology could have notable advantages over classical computing technology, including a faster speed and the ability to tackle more complex problems. In recent years, some researchers have also been exploring the possible establishment of a "quantum internet," a network that would allow quantum devices to exchange information, just like classical computing devices exchange information today.

The quantum internet could open fascinating possibilities for numerous quantum technology applications. For instance, it could enable more secure communications, more precise remote sensing and distributed quantum computing networks.

Researchers at the University of Science and Technology of China and Jinan Institute of Quantum Technology have recently demonstrated quantum entanglement  between two memory devices located at 12.5 km apart from each other within an urban environment. Their paper, published in Physical Review Letters, could be a further step towards the development of a quantum internet.

In their experiment, researchers  introduced two quantum nodes in different locations in an urban environment, placing them at a 12.5 km distance from one another. In the first node, dubbed node A, they entangled their first quantum memory with a single photon. This single photon was then sent to node B and stored within the second quantum memory.

In this way they entangled the two remote quantum memories.

Xi-Yu Luo et al, Postselected Entanglement between Two Atomic Ensembles Separated by 12.5 km, Physical Review Letters (2022). DOI: 10.1103/PhysRevLett.129.050503

Yong Yu et al, Entanglement of two quantum memories via fibres over dozens of kilometres, Nature (2020). DOI: 10.1038/s41586-020-1976-7

Young mice transfused with blood from old mice became fatigued faster and ran shorter distances

A team of researchers from Korea University College of Medicine, the University of California and the Buck Institute for Research on Aging reports that transfusing young mice with blood from older mice makes them grow fatigued and unable to run long distances. The study is published in the journal Nature Metabolism. In 2005, a team of researchers at the University of California stitched pairs of old/young mice together to learn more about the aging process—in that effort, the mice were conjoined; they shared not only blood, but some organs. Testing of the older mice showed that the infusion of younger blood resulted in the reversal of some signs of aging. In this new effort, the researchers tested the process in reverse without resorting to conjoining. The work involved transfusing blood from an aged, two-year-old mouse into mice that were just three months old every day for a week, and then studying the young mice to measure the impact. Putting the mice on a treadmill and getting them to run showed that the young mice became fatigued faster and were not able to run as far as a control group (young mice transfused with blood from other young mice.) The young mice transfused with the blood of older mice showed markers for aging of the liver and kidney damage. The researchers also ran the experiment in reverse, giving old mice young blood, which resulted in reductions in fibrosis and lipids—and also fatigue. There was also an increase in endurance. The researchers suggest that it is likely that cells in the blood of older mice held a senescence-associated secretory phenotype, leading to muscle weakness, tissue damage and other signs of aging in the transfused younger mice. They suggest it also seems possible that cells in the blood from the older mice had ceased reproducing and were having an impact on the younger cells. The researchers also took an indirect approach to testing whether similar results might be observed in humans—they placed cells taken from an older person into plasma from a younger person. Six days later, they found biomarkers of aging.

Ok Hee Jeon et al, Systemic induction of senescence in young mice after single heterochronic blood exchange, Nature Metabolism (2022). DOI: 10.1038/s42255-022-00609-6

Pre-fertilization DNA transfer to avoid mitochondrial disease inheritance appears safe

Transferring the nuclear genome from one egg into the cytoplasm of a donor egg is a strategy to enable women carrying mutations in their mitochondrial DNA to have healthy babies. A new study  published August 16 in the open-access journal PLOS Biology, uses multiple "omics" techniques to show that this strategy, called spindle transfer, is likely to be safe, with little evidence of genetic or functional difference between the resulting embryos and healthy control in vitro fertilization (IVF) embryos. The results are likely to spur further adoption of spindle transfer for IVF when there is a risk of mitochondrial disease.

Mitochondria, the energy powerhouses of the cell, contain their own DNA, mutations in which can cause a variety of inherited diseases, including metabolic, muscular, and neurologic disorders. In human reproduction, only maternal mitochondria, contained in the egg, are inherited. To interrupt that inheritance, techniques have been developed to place parental nuclear DNA into cytoplasm from donor cells carrying healthy mitochondria, either just before fertilization (spindle transfer), or just after (pronuclear transfer).

The "spindle" refers to the division apparatus that holds the nuclear chromosomes in suspension until fertilization. During spindle transfer, the maternal spindle is removed from an unfertilized egg and placed into a donor egg that has had its own spindle removed. (Pronuclear transfer removes the pronucleus, containing both egg and sperm DNA, and places it in a donor embryo whose pronucleus has been removed.) Spindle transfer has been used clinically, but there remain questions about its safety.

To shed light on this question, the authors performed three different types of analyses on single cells from 23 blastocysts following spindle transfer and compared them to 23 control IVF blastocysts. (The blastocyst is the multicellular ball that forms about 5 or 6 days after fertilization, ready for implantation into the uterine wall.) They found no difference in DNA copy number, a measure of genomic integrity, between spindle transfer and control blastocysts. RNA expression profiles were also similar between the two blastocyst types, regardless of which layer of the blastocyst the cells were taken from.

The authors did find a small but significant reduction in the level of DNA demethylation in spindle transfer blastocysts in one layer, the trophectoderm, though not in two other layers. DNA demethylation is one of the processes used to increase gene expression during development, and their analysis suggested that the reduction was evidence of a slight delay in the process, rather than a permanent inability to upregulate the affected genes. It is quite possible that after the blastocyst stage, the spindle transfer embryos can catch up to complete DNA demethylation before implantation.

The researchers concluded that the spindle transfer seems generally safe and does not severely disturb embryonic development. However, given the limitation of the study, more dimensions and larger-scale evaluations are still needed to determine whether this technique can be applied to a wider set of clinical trials.

Single-cell multiomics analyses of spindle-transferred human embryos suggest a mostly normal embryonic development, PLoS Biology (2022). DOI: 10.1371/journal.pbio.3001741

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Adults who, as children, had half their brain removed still able to score well with face and word recognition

A team of researchers at Carnegie Mellon University's Department of Psychology and Neuroscience Institute has found that adults who had a hemispherectomy as a child scored surprisingly well on face and word recognition tests. Their paper is posted on the bioRxiv preprint server. In epilepsy, abnormal brain activity results in chronic seizures. Some people respond well to medication and others due not; for example, some people experience seizures so often that they become incapacitating. Some young patients in these circumstances are given the option of undergoing a hemispherectomy, the complete removal of the left or right hemisphere of the brain. Prior research has shown that these procedures, when done at a very young age, allow most patients to retain their IQ and their ability to communicate and live relatively normal lives. In sharp contrast, damage to either hemisphere, much less removal of one or the other in adults, leads to severe symptoms or death. In this new effort, the researchers sought to learn more about the cognitive abilities of adults who had undergone a hemispherectomy. Forty subjects were shown grayscale pictures of human faces without hair for 750 milliseconds, followed by a pause of 150 milliseconds. Then another face was shown for 150 milliseconds after which the volunteer reported whether it was the same face or not. The whole process was then repeated several times with different faces. The researchers then repeated the entire exercise but used simple, four-letter words. The researchers expected that those volunteers who had only their right hemisphere would do well at face recognition but not as well at word recognition, since the right hemisphere is generally used to process images while the left hemisphere processes words; they expected the opposite results for those who still had just their left hemisphere. Instead, the researchers found that both groups performed nearly equally well and both were on average 86% accurate on the tests compared to a control group consisting of people who had not undergone an hemispherectomy, with average 96% accuracy. The researchers also conducted a nearly identical experiment in which the faces and words were shown off to the left or right; both groups still did surprisingly well—but there was one interesting difference. In comparing their results with the control group, those who had undergone a hemispherectomy did as well as the control group in identifying images or words in two instances—when a word was placed on the left side, or a face on the right.

Michael C. Granovetter et al, With Childhood Hemispherectomy, One Hemisphere Can Support—But is Suboptimal for—Word and Face Recognition (2020). DOI: 10.1101/2020.11.06.371823

Modern pesticides damage the brain of bees so they can't move in a straight line

The challenge to let people walk back and forth in a straight line isn't just used by police to test if drivers are intoxicated: it's also used by neurologists to diagnose neurological disorders like ataxia, where parts of the brain that coordinate movement are impaired. Now, researchers use an insect version of this challenge to show for the first time that modern pesticides damage the nervous system of honeybees so that it becomes hard for them to walk in a straight line. The results are published in Frontiers in Insect Science.

The commonly used insecticides like sulfoxaflor and the neonicotinoid imidacloprid can profoundly impair the visually guided behavior of honeybees. New research results are reason for concern because the ability of bees to respond appropriately to visual information is crucial for their flight and navigation, and thus their survival.

The results add to what the Food and Agriculture Organization of the United Nations and the World Health Organization have called the "rapidly growing body of evidence [which] strongly suggests that the existing levels of environmental contamination [from neonicotinoid pesticides] are causing large-scale adverse effects on bees and other beneficial insects."

The researchers also show with molecular techniques that pesticide-exposed bees tended to have elevated proportion of dead cells in parts of the brain's optic lobes, important for processing visual input. Likewise, key genes for detoxification were dysregulated after exposure.

Rachel H. Parkinson et al, Honeybee optomotor behaviour is impaired by chronic exposure to insecticides, Frontiers in Insect Science (2022). DOI: 10.3389/finsc.2022.936826

'Forever chemicals' destroyed by simple new method

PFAS, a group of manufactured chemicals commonly used since the 1940s, are called "forever chemicals" for a reason. Bacteria can't eat them; fire can't incinerate them; and water can't dilute them. And, if these toxic chemicals are buried, they leach into surrounding soil, becoming a persistent problem for generations to come.

Now chemists have done the seemingly impossible. Using low temperatures and inexpensive, common reagents, the research team developed a process that causes two major classes of PFAS compounds to fall apart, leaving behind only benign end products. The simple technique potentially could be a powerful solution for finally disposing of these harmful chemicals, which are linked to many dangerous health effects in humans, livestock and the environment.

Even just a tiny, tiny amount of PFAS causes negative health effects, and it does not break down. We can't just wait out this problem.

The secret to PFAS's indestructibility lies in its chemical bonds. PFAS contains many carbon-fluorine bonds, which are the strongest bonds in organic chemistry. As the most electronegative element in the periodic table, fluorine wants electrons, and badly. Carbon, on the other hand, is more willing to give up its electrons.

"When you have that kind of difference between two atoms—and they are roughly the same size, which carbon and fluorine are—that's the recipe for a really strong bond.

Scientists now  found a weakness. PFAS contains a long tail of unyielding carbon-fluorine bonds. But at one end of the molecule, there is a charged group that often contains charged oxygen atoms. Researchers targeted this head group by heating the PFAS in dimethyl sulfoxide—an unusual solvent for PFAS destruction—with sodium hydroxide, a common reagent. The process decapitated the head group, leaving behind a reactive tail.

That triggered all these reactions, and it started spitting out fluorine atoms from these compounds to form fluoride, which is the safest form of fluorine.

After discovering the PFAS degradation conditions, researchers also discovered that the fluorinated pollutants fall apart by different processes than generally assumed. A simulation showed that PFAS actually falls apart two or three carbons at a time—a discovery that matched the researchers' experiments. By understanding these pathways, researchers can confirm that only benign products remain. This new knowledge also could help guide further improvements to the method.

Brittany Trang et al, Low-temperature mineralization of perfluorocarboxylic acids, Science (2022). DOI: 10.1126/science.abm8868. www.science.org/doi/10.1126/science.abm8868

Swarms of microrobots could be solution to unblocking medical devices in body

Swarms of microrobots injected into the human body could unblock internal medical devices and avoid the need for further surgery, according to new research .

The study is the first-time scientists have developed magnetic microrobotics to remove deposits in shunts—common internal medical devices used to treat a variety of conditions by draining excess fluid from organs.

Shunts are prone to malfunctioning, often caused by blockages due to a build-up of sediment. The sediment not only narrows and obstructs liquid passing through the shunt, but it also affects the shunt's flexibility. This leads to patients needing repeated, invasive surgeries throughout their lives either to replace the shunt or use a catheter to remove the blockage.

However, this new research  has shown there could be a wireless, non-invasive alternative to clearing the blockage in a shunt. It has shown that a swarm of hundreds of microrobots—made of nano size magnetic nanoparticles—injected into the shunt could remove the sediment instead.

Once the magnetic microrobots are injected into the shunt they can be moved along the tube to the affected area using a magnetic field, generated by a powerful magnet on the body's surface. The swarm of microrobots can then be moved so they scrape away the sediment, clearing the tube.

"The non-invasive nature of this method is a considerable advantage to existing methods as it will potentially eliminate the risk of surgery and a surgery-related infection, thereby decreasing recovery time.

With each microrobot smaller than the width of a human hair, once the swarm has done its job, it can either be guided to the stomach via a magnetic field or bodily fluid, so they leave the body naturally. Because the microrobots have very high biocompatibility they will not cause toxicity.

The research also found a direct relation between the strength of the magnetic field and the success of scraping away the sediment in the shunt.

This is the first proof-of-concept experiment using microswarms for opening a blockage in a shunt.

A. Moghanizadeh et al, A novel non-invasive intervention for removing occlusions from shunts using an abrading magnetic microswarm, IEEE Transactions on Biomedical Engineering (2022). DOI: 10.1109/TBME.2022.3192807

Turning to the laws of physics to study how cells move

Scientists have long been concerned with trying to understand how cells move, for example in pursuit of new ways to control the spread of cancer. The field of biology continues to illuminate the infinitely complex processes by which collections of cells communicate, adapt, and organize along biochemical pathways.

Turning to the laws of physics, researchers have taken a fresh look at how cells move, revealing similarities between the behaviour of cell tissue and the simplest water droplets. They have taken a different perspective on how cell motion is determined by the properties of the tissues they're in rather than how they act individually.

Published in Physical Review Letters, the researchers’ initial experiments used mechanical techniques to measure the surface tension of a simple "ball" of cell tissue to reveal similarities with the thermo-dynamic properties of water droplets, but with noticeable differences.

With a water droplet the surface tension is constant and doesn't change with droplet size.

However, the scientists found that in the case of a "droplet" of cancer cells surface tension was size dependent—the smaller the tissue the higher the surface tension, and the higher the pressure within the tissue.

Next, they applied a surface tension gradient to show that cells within the tissue moved rapidly and collectively, much like the way the surface of water moves when detergent is added. Their findings were published in Physical Review Fluids.

This so called "Marangoni" effect occurs when the forces at the surface of a tissue drive the motion of cells inside.

To complete the puzzle, the scientists allowed the tissue to adhere to a surface, mimicking the way a tumor grows and spreads. Cells emerged from the ball of tissue like water droplets "wetting" a receptive—or hydrophilic—surface. In some conditions, the wetting increased the internal pressure of the tissue, helping to push cells out.

Published today in Physical Review X, these findings cast new light on the degree to which cells "migrate" or whether pressure from surface tension promotes cell movement.

This new work shows that the bulk properties of tissue, including the surface tension and pressure, matter when it comes to the ability of cells to migrate out of a model tumor.

M. S. Yousafzai et al, Active Regulation of Pressure and Volume Defines an Energetic Constraint on the Size of Cell Aggregates, Physical Review Letters (2022). DOI: 10.1103/PhysRevLett.128.048103

Vikrant Yadav et al, Gradients in solid surface tension drive Marangoni-like motions in cell aggregates, Physical Review Fluids (2022). DOI: 10.1103/PhysRevFluids.7.L031101

Muhammad Sulaiman Yousafzai et al, Cell-Matrix Elastocapillary Interactions Drive Pressure-Based Wetting of Cell Aggregates, Physical Review X (2022). DOI: 10.1103/PhysRevX.12.031027

Can a human with a spinal cord injury walk and run? Discovering clues with neuromorphic technology

 An international research team  has succeeded in recovering muscle movements in a model of paralyzed mice through organic artificial nerves. The result was published in Nature Biomedical Engineering.

The nerves, which are essential for life activities as well as having a significant impact on quality of life, are easily damaged by various causes such as physical injury, genetic causes, secondary complications, and aging. In addition, once nerves are damaged they are difficult to reconstruct, and some or all their bodily functions are permanently lost due to poor bio-signaling.

Among the various methods for rehabilitation in patients with neurological damage, Functional Electrical Stimulation (FES), which is currently actively used in clinical practice, uses computer-controlled signals. Through this setup, electrical stimulation is applied to muscles that are no longer arbitrarily controllable in patients with neuropathy to induce muscle contraction, resulting in functionally useful movements in the biological body even though they are confined in a specific space. However, this conventional approach has limitations that are not suitable for long-term use in patients' daily lives because they involve complex digital circuits and computers for signal processing to stimulate muscles, consuming a lot of energy and poor biocompatibility in the process.

To solve the problem, the research team succeeded in controlling the leg movement of mice only with artificial nerves without a complex and bulky external computer using stretchable, low-power organic nanowire neurormorphic devices that emulate the structure and function of bio nerve fibers. The stretchable artificial nerve consists of a strain sensor that simulates a proprioceptor which detects muscle movements, an organic artificial synapse that simulates a biological synapse, and a hydrogel electrode for transmitting signals to the leg muscles.

The researchers adjusted the movement of the mouse legs and the contraction force of the muscles according to the firing frequency of the action potential transmitted to the artificial synapse with a principle similar to that of the biological nerve, and the artificial synapse implements smoother and more natural leg movements than the usual FES.

In addition, the artificial proprioceptor detects the leg movement of the mouse and gives real-time feedback to the artificial synapse to prevent muscle damage due to excessive leg movement.

The researchers succeeded in allowing a paralyzed mouse to kick the ball or walk and run on the treadmill. Furthermore, the research team showed the applicability of artificial nerves in the future for voluntary movement by sampling pre-recorded signals from the motor cortexes of moving animals and moved the legs of mice through artificial synapses.

The researchers discovered a new application feasibility in the field of neuromorphic technology, which is attracting attention as a next-generation computing device by emulating the behavior of a biological neural network.

https://www.nature.com/articles/s41551-022-00918-x

https://www.eurekalert.org/news-releases/961673

How the brain gathers threat cues and turns them into fear

Scientists have uncovered a molecular pathway that distills threatening sights, sounds and smells into a single message: Be afraid. A molecule called CGRP enables neurons in two separate areas of the brain to bundle threatening sensory cues into a unified signal, tag it as negative and convey it to the amygdala, which translates the signal into fear.

The research, published in Cell Reports on August 16, 2022, may lead to new therapies for fear-related disorders such as post-traumatic stress disorder (PTSD) or hypersensitivity disorders such as autism, migraines and fibromyalgia.

The brain pathway researchers now discovered works like a central alarm system. The CGRP neurons are activated by negative sensory cues from all five senses—sight, sound, taste, smell and touch. Identifying new threat pathways provides insights into treating fear-related disorders.

Most external threats involve multisensory cues, such as the heat, smoke and smell of a wildfire. Previous research showed that different pathways independently relay sound, sight, and touch threat cues to multiple brain areas. A single pathway that integrates all these cues would be beneficial to survival, but no one had ever found such a pathway.

Previous research also showed that the amygdala, which initiates behavioral responses and forms fear memories to environmental and emotional stimuli, receives heavy input from brain regions that are laden with a chemical associated with aversion, the neuropeptide CGRP (calcitonin gene-related peptide).

Based on these two pools of research,  researchers now proposed that CGRP neurons, found especially in subregions of the thalamus and the brainstem, relay multisensory threat information to the amygdala. These circuits may both generate appropriate behavioral responses and help form aversive memories of threat cues.

The researchers conducted several experiments to test their hypotheses. They recorded CGRP neuron activity using single-cell calcium imaging while presenting mice with multisensory threat cues, enabling the researchers to pinpoint which sensory modality involved which sets of neurons. They determined the path the signals took after leaving the thalamus and brainstem using different colored fluorescent proteins. And they conducted behavioral tests to gauge memory and fear.

Taken together, their findings show that two distinct populations of CGRP neurons—one in the thalamus, one in the brainstem—project to nonoverlapping areas of the amygdala, forming two distinct circuits. Both populations encode threatening sights, sounds, smells, tastes and touches by communicating with local brain networks. Finally, they discovered that both circuits are necessary for forming aversive memories—the kind that tell you, "Stay away."

While mice were used in this study, the same brain regions also abundantly express CGRP in humans. This suggests that the circuits reported here may also be involved in threat perception-related psychiatric disorders.

https://www.cell.com/cell-reports/fulltext/S2211-1247(22)01039-7?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS2211124722010397%3Fshowall%3Dtrue

Non-nutritive sweeteners affect human microbiomes and can alter glycemic responses

Since the late 1800s non-nutritive sweeteners have promised to deliver all the sweetness of sugar with none of the calories. They have long been believed to have no effect on the human body, but researchers publishing in the journal Cell on August 19 challenge this notion by finding that these sugar substitutes are not inert, and, in fact, some can alter human consumers' microbiomes in a way that can change their blood sugar levels.

In 2014 researchers found that non-nutritive sweeteners affected the microbiomes of mice in ways that could impact their glycemic responses. They were interested in whether these results would also be found in humans.

To address this important question, the researchers  carefully screened over 1,300 individuals for those who strictly avoid non-nutritive sweeteners in their day-to-day lives, and identified a cohort of 120 individuals. These participants were broken into six groups: two controls and four who ingested well below the FDA daily allowances of either aspartame, saccharin, stevia, or sucralose.

In subjects consuming the non-nutritive sweeteners, scientists could identify very distinct changes in the composition and function of gut microbes, and the molecules they secret into peripheral blood. This seemed to suggest that gut microbes in the human body are rather responsive to each of these sweeteners.

When they looked at consumers of non-nutritive sweeteners as groups, they found that two of the non-nutritive sweeteners, saccharin and sucralose, significantly impacted glucose tolerance in healthy adults. Interestingly, changes in the microbes were highly correlated with the alterations noted in people's glycemic responses.

To establish causation, the researchers transferred microbial samples from the study subjects to germ-free mice—mice that have been raised in completely sterile conditions and have no microbiome of their own.

The results were quite striking. In all of the non-nutritive sweetener groups, but in none of the controls, when the researchers transferred into these sterile mice the microbiome of the top responder individuals collected at a time point in which they were consuming the respective non-nutritive sweeteners, the recipient mice developed glycemic alterations that very significantly mirrored those of the donor individuals. In contrast, the bottom responders' microbiomes were mostly unable to elicit such glycemic responses. These results suggest that the microbiome changes in response to human consumption of non-nutritive sweetener may, at times, induce glycemic changes in consumers in a highly personalized manner.

The effects of the sweeteners will vary person to person because of the incredibly unique composition of our microbiome.

 Eran Elinav, Personalized microbiome-driven effects of non-nutritive sweeteners on human glucose tolerance, Cell (2022). DOI: 10.1016/j.cell.2022.07.016. www.cell.com/cell/fulltext/S0092-8674(22)00919-9

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Researchers discover a material that can learn like the brain

Researchers have discovered that Vanadium Dioxide (VO₂), a compound used in electronics, is capable of "remembering" the entire history of previous external stimuli. This is the first material to be identified as possessing this property, although there could be others.

A PhD student made a chance discovery during his research on phase transitions in Vanadium Dioxide (VO₂). VO₂ has an insulating phase when relaxed at room temperature, and undergoes a steep insulator-to-metal transition at 68 °C, where its lattice structure changes. Classically, VO₂ exhibits a volatile memory: "the material reverts back to the insulating state right after removing the excitation" . For his thesis, he set out to discover how long it takes for VO₂ to transition from one state to another. But his research led him down a different path: after taking hundreds of measurements, he observed a memory effect in the material's structure.

In his experiments, the student applied an electric current  to a sample of VO₂. The current moved across the material, following a path until it exited on the other side. As the current heated up the sample, it caused the VO₂ to change state. And once the current had passed, the material returned to its initial state.

He then applied a second current pulse to the material, and saw that the time it took to change state was directly linked to the history of the material. The VO₂ seemed to 'remember' the first phase transition and anticipate the next. The researchers didn't expect to see this kind of memory effect, and it has nothing to do with electronic states but rather with the physical structure of the material. It's a novel discovery: no other material behaves in this way.

The researchers went on to find that VO₂ is capable of remembering its most recent external stimulus for up to three hours. The memory effect could in fact persist for several days, but we don't currently have the instruments needed to measure that.

The research team's discovery is important because the memory effect they observed is an innate property of the material itself. Engineers rely on memory to perform calculations of all kinds, and materials that could enhance the calculation process by offering greater capacity, speed and miniaturization are in high demand. VO₂ ticks all three of these boxes. What's more, its continuous, structural memory sets it apart from conventional materials that store data as binary information dependent on the manipulation of electronic states.

The researchers performed a host of measurements to arrive at their findings. They also corroborated their results by applying the new method to different materials at other laboratories around the world. This discovery replicates well what happens in the brain, as VO₂ switches act just like neurons.

Mohammad Samizadeh Nikoo, Electrical control of glass-like dynamics in vanadium dioxide for data storage and processing, Nature Electronics (2022). DOI: 10.1038/s41928-022-00812-z. www.nature.com/articles/s41928-022-00812-z

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Study shows 90% of marine species at risk of extinction by 2100 if greenhouse gas emissions are not curbed

An international team of researchers has found that approximately 90% of all marine life on Earth will be at risk of extinction by 2100 if greenhouse gas emissions are not curbed. In their paper published in the journal Nature Climate Change, the group outlines their study of thousands of marine species and how greenhouse gas emissions might impact them in the future.

Greenhouse gas emissions impact the world's climate in two ways. They raise the temperature of the atmosphere (and by extension, Earth's surfaces and bodies of water) by holding in heat, and in the case of CO₂ emissions, they make water more acidic, like carbonated soft drinks. And as emissions continue to be pumped into the atmosphere despite dire warnings from scientists around the world, more research is being conducted to learn about its possible impact. In this new effort, the researchers took a broad look at the impact of greenhouse gas emissions on ocean life.

The work involved estimating the impact of certain levels of greenhouse gas emissions on marine life in the future. They looked specifically at 25,000 species, including fish, bacteria, plants and protozoans living in the top 100 meters of the world's oceans. They found that under the worst scenario, in which emissions lead to global atmospheric temperature increases of 3 to 5 degrees Celsius, approximately 90% of all marine life will disappear. They also found that if emissions are cut to the extent outlined by the Paris Climate Agreement, which would keep global temperature increases to below 2 degrees Celsius, then the risk of extinction would be reduced by approximately 98%.

The researchers also found that larger top predators are more at risk than smaller predators, as are fish species  in areas where they are heavily fished by humans. Those at lowest risk, on the other hand, include small, short-lived species. Notably, Earth has not seen a die-off as great as these projections since the Great Dying 252 million years ago.

Daniel G. Boyce et al, A climate risk index for marine life, Nature Climate Change (2022). DOI: 10.1038/s41558-022-01437-y

Experiment on YouTube reveals potential to 'inoculate' users against misinformation

Here's what a black hole sounds like, according to NASA.

Data Sonification: Black Hole at the Center of the Perseus Galaxy Cluster (X-ray)

New research on the risks of lead exposure from bullets used in big game hunting

The lead in some bullets used for hunting deer, moose, and elk is toxic to the humans who eat the harvested meat and to scavenger animals that feast on remains left in the field.