Did the coronavirus jump from animals to people twice?

Fine-tooth comb

They analysed 1,716 SARS-CoV-2 genomes in a popular online genome repository called GISAID that were collected before 28 February 2020, and identified 38 such ‘intermediate’ genomes.

But when they looked at the sequences more closely, they found that many of these also contained mutations in other regions of their genomes. And they say that these mutations are definitively associated with either lineage A or lineage B — which discredits the idea that the corresponding viral genomes date to an intermediate stage of evolution between the two lineages.

The authors suggest that a laboratory or computer error probably occurred in sequencing one of the two mutations in these ‘intermediate’ genomes. “The more we dug, the more it looked like, maybe we can’t trust any of the ‘transitional’ genomes,” says study co-author Michael Worobey, an evolutionary biologist at the University of Arizona in Tucson.

Such sequencing errors are not unusual, say researchers. Software can sometimes fill in gaps in the raw data with incorrect sequences, and viral samples can become contaminated, notes Richard Neher, a computational biologist at the University of Basel in Switzerland. “Such mishaps are not surprising,” he says. “Especially early in the pandemic, when protocols weren’t very established and people tried to generate data as fast as they could.”

Several researchers contacted by Nature, who sequenced some of the samples included in the study, say it is unlikely that their sequences include errors in the two key nucleotides.

But the study authors counter that even if some of the genomes were sequenced correctly, other parts of the same genomes, or the locations from which the samples were collected, still clearly indicate that they belong to only one or the other lineage.

“It is very unlikely” that any of the so-called intermediate genomes are actually transitional genomes, says study co-author

part2

doi: https://doi.org/10.1038/d41586-021-02519-1

part 3

References

Ebola virus in survivors can trigger outbreaks years after infection

Ebola survivors can relapse and trigger outbreaks at least five years after infection, and long-term follow-up of former patients is needed to prevent devastating flare-ups, according to new research.

Scientists already knew Ebola could lie dormant in survivors, who test negative because the virus is in tissue rather than circulating in the blood.

But analysis of an outbreak this year in Guinea, published Wednesday in the journal Nature, found these "virus reservoirs" can awaken and cause new infections and transmission years on.

To trace the source of the Guinea outbreak, which involved 16 confirmed cases, 12 of whom died, researchers analysed the genomes of samples from several patients.

Ebola outbreaks are usually thought to result from the virus "spilling" from an animal host to a human.

But the analysis showed the Guinea strain was virtually identical to that from a 2013-16 wave.

If the virus had been circulating actively in the community since then, it would have accumulated a certain number of mutations as it spread.

Instead, the 2021 virus had just 12 changes, "far fewer than would be expected... during six years of sustained human-to-human transmission".

That strongly suggests the source was reactivated virus that had lain dormant in a survivor.

This is the longest known time between the declared end of an epidemic and a viral resurgence.

How and why dormant Ebola virus suddenly awakens and sickens a person remains something of a mystery, though there are some tantalising clues.

Sometimes a spike in Ebola antibodies can be detected in survivors at a given time -- a possible sign that the body is responding to a resurgent virus.

Around two-thirds of Ebola survivors have high antibody levels even five years after infection, but "the question to pose is what happens if there's a resurgence in the people whose immunity has dropped.

https://www.nature.com/articles/d41586-021-02378-w

source: Agence France-Presse

https://researchnews.cc/news/8930/Ebola-virus-in-survivors-can-trig...

The microbial molecule that turns plants into zombies

A newly discovered manipulation mechanism used by parasitic bacteria to slow down plant aging, may offer new ways to protect disease-threatened food crops.

Parasites manipulate the organisms they live off to suit their needs, sometimes in drastic ways. When under the spell of a parasite, some plants undergo such extensive changes that they are described as "zombies". They stop reproducing and serve only as a habitat and host for the parasitic pathogens.

Until now, there's been little understanding of how this happens on a molecular and mechanistic level.

Research from the Hogenhout group at the John Innes Centre and collaborators published in Cell, has identified a manipulation molecule produced by Phytoplasma bacteria to hijack plant development. When inside a plant, this protein causes key growth regulators to be broken down, triggering abnormal growth.

Phytoplasma bacteria belong to a group of microbes that are notorious for their ability to reprogramme the development of their host plants. This group of bacteria are often responsible for the 'witches' brooms' seen in trees, where an excessive number of branches grow close together.

These bushy outgrowths are the result of the plant being stuck in a vegetative "zombie" state, unable to reproduce and therefore progress to a 'forever young' status. Phytoplasmas are a spectacular example of how the reach of genes can extend beyond the organisms to impact surrounding environments.

The new findings show how the bacterial protein  known as SAP05 manipulates plants by taking advantage of some of the host's own molecular machinery.

This machinery, called the proteasome, usually breaks down proteins that are no longer needed inside plant cells. SAP05 hijacks this process, causing plant proteins that are important in regulating growth and development, to effectively be thrown in a molecular recycling centre.

Without these proteins, the plant's development is reprogrammed to favour the bacteria, triggering the growth of multiple vegetative shoots and tissues and putting the pause on the plant ageing.

Parasitic modulation of host development by ubiquitin-independent protein degradation, Cell www.cell.com/cell/fulltext/S0092-8674(21)01012-6. DOI: 10.1016/j.cell.2021.08.029

https://phys.org/news/2021-09-microbial-molecule-zombies.html?utm_s...

How do cells acquire their shapes?

 A new mechanism that a simple yeast cell uses to acquire its shape has been identified recently by researchers. 

When cells move or grow, they must add new membrane to those growth regions.

The process of membrane delivery is called exocytosis. Cells also must deliver this membrane to a specific location in order to maintain a sense of direction―called "polarization"―or grow in a coordinated manner.

Researchers have demonstrated that these processes are coupled: local excess of exocytosis causes some of the proteins attached to the membrane to move ('flow') away from the growth region. These proteins that move away mark the non-growing cell region, thus establishing a self-sustaining pattern, which gives rise to the tubular shape of these yeast cells. 

This is the first time that this mechanism for cell patterning―the process by which cells acquire spatial nonuniformities on their surfaces―has been identified.

 Cell patterning by secretion-induced plasma membrane flows, Science Advances (2021). DOI: 10.1126/sciadv.abg6718

https://phys.org/news/2021-09-cells-mechanism.html?utm_source=nwlet...

How to make dormant seeds to germinate

Seeds that would otherwise lie dormant will spring to life with the aid of a new chemical discovered by researchers. 

Plants have the ability to perceive drought. When they do, they emit a hormone that helps them hold on to water. This same hormone, ABA, sends a message to seeds that it isn't a good time to germinate, leading to lower crop yields and less food in places where it's hot—an increasingly long list as a result of climate change.

"If you block ABA, you mess with the chemical pathway that plants use to prevent seed germination. A new chemical, Antabactin, does exactly this. If we apply it,  dormant seeds will sprout.

Demonstrations of Antabactin's effectiveness are described in a new paper published in the Proceedings of the National Academy of Sciences.

Aditya S. Vaidya et al, Click-to-lead design of a picomolar ABA receptor antagonist with potent activity in vivo, Proceedings of the National Academy of Sciences (2021). DOI: 10.1073/pnas.2108281118

https://phys.org/news/2021-09-chemical-discovery-reluctant-seeds.ht...

Mass extinction: A warning that this can happen now too

The end-Permian mass extinction event of roughly 252 million years ago—the worst such event in earth's history—has been linked to vast volcanic emissions of greenhouse gases, a major temperature increase, and the loss of almost every species in the oceans and on land.

Now, it seems that even the lakes and rivers were no safe havens. A recent study published by an international team of researchers  has identified a new cause of extinction during extreme warming events: toxic microbial blooms.

In a healthy ecosystem, microscopic algae and cyanobacteria provide oxygen to aquatic animals as a waste product of their photosynthesis. But when their numbers get out of control, these microbes deplete free oxygen, and even release toxins into the water. By studying the fossil, sediment, and chemical records of rocks near Sydney, Australia, the researchers discovered that several pulses of bloom events had occurred soon after the first volcanic rumblings of the end-Permian mass extinction. Once the bottom-feeder animals, or "detritivores," were killed off, there was no one left to keep the microbes in check. The fresh water systems then seethed with algae and bacteria, delaying the recovery of animals for perhaps millions of years.

We're seeing more and more toxic algae blooms in lakes and in shallow marine environments that's related to increases in temperature and changes in plant communities which are leading to increases in nutrient contributions to freshwater environments. So, a lot of parallels to today. The volcanism was a source of CO₂ in the past but we know that the rate of CO₂ input that was seen back then was similar to the rate of CO₂ increases we're seeing today because of anthropogenic effects.

We can get a sense of how much climate has changed in the past, what the extremes are, how fast it can change, what the causes of climate change are and that gives us a nice backdrop for understanding what's happening today. The end-Permian is one of the best places to look for parallels with what's happening now.

The other big parallel is that the increase in temperature at the end of the Permian coincided with massive increases in forest fires. One of the things that that destroyed whole ecosystems was fire, and we're seeing that right now in several  places .

We should be concerned like hell!

Chris Mays et al, Lethal microbial blooms delayed freshwater ecosystem recovery following the end-Permian extinction, Nature Communications (2021). DOI: 10.1038/s41467-021-25711-3

https://phys.org/news/2021-09-animals-died-toxic-soup-earth.html?ut...

Do the northern lights make sounds that you can hear?

https://theconversation.com/do-the-northern-lights-make-sounds-that...

Antibodies from original strain COVID-19 infection don't bind to variants, study finds

People infected with the original strain of the virus that causes COVID-19 early in the pandemic produced a consistent antibody response, making two main groups of antibodies to bind to the spike protein on the virus’s outer surface. However, those antibodies don’t bind well to newer variants, a new study found.

Researchers found that many antibody sequences converged into two main groups, indicating a consistent human immune response to the virus. The researchers studied the convergent antibodies’ ability to bind to several variants and found that they no longer bound to some. The finding has implications for the ability of new variants to reinfect people who contracted earlier versions of the virus, as well as for the continuing efficacy of vaccines and the design of possible vaccine boosters.

Even though this antibody response is very common with the original strain, it doesn’t really interact with variants. That, of course, raises the concern of the virus evolving to escape the body’s main antibody response. Some antibodies should still be effective – the body makes antibodies to many parts of the virus, not only the spike protein – but the particular groups of antibodies that we saw in this study will not be as effective.

The researchers said they would like to conduct similar studies characterizing antibody responses to delta and other variants, to see whether they also produce a convergent response and how it differs from the original strain. 

It is expected that the antibody response to those variants would be quite different. 

https://www.nature.com/articles/s41467-021-24123-7'

https://news.illinois.edu/view/6367/1126344363

https://researchnews.cc/news/8965/Antibodies-from-original-strain-C...

Will Indian researchers lose free access to scientific papers?

It’ll depend on the outcome of an ongoing case against SciHub and LibGen websites in the Delhi High Court.

On December 21, 2020, academic publishers Elsevier Ltd, Wily Pvt Ltd, and the American Chemical Society sued websites SciHub and Library Genesis, also known as LibGen, for copyright infringement in the Delhi High Court, demanding that ISP providers permanently block them in India.

These websites are a primary source for researchers in India, making available for free thousands of otherwise paywalled research papers. Because, as SciHub notes, “Research should be free to read.” Having intellectual property restrictions in research throttle access to and flow of knowledge while science can only progress when it’s widely read and debated.

Elsevier owns over 2,600 journals, including the Lancet, and all of them are paywalled with subscription rates going up to thousands of dollars, making the latest knowledge hard to access for researchers.

part 1

https://www.newslaundry.com/2021/09/18/will-indian-researchers-lose...

The Future of Wearable Tech

Engineers create light-emitting plants that can be charged repeatedly

Using specialized nanoparticles embedded in plant leaves, MIT engineers have created a light-emitting plant that can be charged by an LED. After 10 seconds of charging, plants glow brightly for several minutes, and they can be recharged repeatedly.

These plants can produce light that is 10 times brighter than the first generation of glowing plants that the research group reported in 2017.

Creating ambient light with the renewable chemical energy of living plants is a bold idea. It represents a fundamental shift in how we think about living plants and electrical energy for lighting.

The particles can also boost the light production of any other type of light-emitting plant, including those the researchers originally developed. Those plants use nanoparticles containing the enzyme luciferase, which is found in fireflies, to produce light. The ability to mix and match functional nanoparticles inserted into a living plant to produce new functional properties is an example of the emerging field of "plant nanobionics."

Their  first generation of light-emitting plants contained nanoparticles that carry luciferase and luciferin, which work together to give fireflies their glow. Using these particles, the researchers generated watercress plants that could emit dim light, about one-thousandth the amount needed to read by, for a few hours.

In the new study, Strano and his colleagues wanted to create components that could extend the duration of the light and make it brighter. They came up with the idea of using a capacitor, which is a part of an electrical circuit that can store electricity and release it when needed. In the case of glowing plants, a light capacitor can be used to store light in the form of photons, then gradually release it over time.

To create their "light capacitor," the researchers decided to use a type of material known as a phosphor. These materials can absorb either visible or ultraviolet light and then slowly release it as a phosphorescent glow. The researchers used a compound called strontium aluminate, which can be formed into nanoparticles, as their phosphor. Before embedding them in plants, the researchers coated the particles in silica, which protects the plant from damage.

The particles, which are several hundred nanometers in diameter, can be infused into the plants through the stomata—small pores located on the surfaces of leaves. The particles accumulate in a spongy layer called the mesophyll, where they form a thin film. A major conclusion of the new study is that the mesophyll of a living plant can be made to display these photonic particles without hurting the plant or sacrificing lighting properties, the researchers say.

This film can absorb photons either from sunlight or an LED. The researchers showed that after 10 seconds of blue LED exposure, their plants could emit light for about an hour. The light was brightest for the first five minutes and then gradually diminished. The plants can be continually recharged for at least two weeks.

Pavlo Gordiichuk et al, Augmenting the living plant mesophyll into a photonic capacitor, Science Advances (2021). DOI: 10.1126/sciadv.abe9733

https://phys.org/news/2021-09-light-emitting-repeatedly.html?utm_so...

Nano-scale discovery could help to cool down overheating in electronics

A team of physicists  solved the mystery behind a perplexing phenomenon in the nano realm: why some ultra-small heat sources cool down faster if you pack them closer together. The findings  could one day help the tech industry design faster electronic devices that overheat less.

Often, heat is a challenging consideration in designing electronics. You build a device then discover that it's heating up faster than desired.

In 2015, physicists  were experimenting with bars of metal that were many times thinner than the width of a human hair on a silicon base. When they heated those bars up with a laser, something strange occurred.

They behaved very counterintuitively. These nano-scale heat sources do not usually dissipate heat efficiently. But if you pack them close together, they cool down much more quickly.

Now, the researchers know why it happens.

In the new study, they used computer-based simulations to track the passage of heat from their nano-sized bars. They discovered that when they placed the heat sources close together, the vibrations of energy they produced began to bounce off each other, scattering heat away and cooling the bars down.

The group's results highlight a major challenge in designing the next generation of tiny devices, such as microprocessors or quantum computer chips: When you shrink down to very small scales, heat does not always behave the way you think it should.

 Directional thermal channeling: A phenomenon triggered by tight packing of heat sources, Proceedings of the National Academy of Sciences (2021). DOI: 10.1073/pnas.2109056118

https://phys.org/news/2021-09-nano-scale-discovery-cool-overheating...

Yeast and bacteria together biosynthesize plant hormones for weed control

Plants regulate their growth and development using hormones, including a group called strigolactones that prevent excessive budding and branching. For the first time, scientists  have synthesized strigolactones from microbes.

Strigolactones also help plant roots form symbiotic relationships with microorganisms that allow the plant to absorb nutrients from the soil. These two factors have led to agricultural interest in using strigolactones to control the growth of weeds and root parasites, as well as improving nutrient uptake.

These root-extruding compounds don't come without risks. They also stimulate germination of witchweeds and broomrapes, which can cause entire crops of grain to fail, making thorough research essential prior to commercial development. Scientists are still learning about the physiological roles played by this diverse group of hormones in plants. Until recently, manufacturing pure strigolactones for scientific study has been difficult and too costly for agricultural use.

The new  work provides a unique platform to investigate strigolactone biosynthesis and evolution, and it lays the foundation for developing strigolactone microbial bioproduction processes as alternative sourcing.

Researchers directed a group that inserted plant genes associated with strigolactone production into ordinary baker's yeast and nonpathogenic Escherichia coli bacteria that together produced a range of strigolactones.

Sheng Wu et al, Establishment of strigolactone-producing bacterium-yeast consortium, Science Advances (2021). DOI: 10.1126/sciadv.abh4048

https://phys.org/news/2021-09-yeast-bacteria-biosynthesize-hormones...

**

Science of Concrete & the Surfside Condo Collapse

The Placebo Effect Is an Amazing Illusion, But That Doesn't Mean It's Medicine

Placebo is a beneficial effect produced by a placebo drug or treatment, which cannot be attributed to the properties of the placebo itself, and must therefore be due to the patient's belief in that treatment.

The placebo is one of science's greatest mysteries. The pill that isn't a pill. The medical illusion that somehow becomes real.

The mind-boggling weirdness of the placebo effect is certainly a strange thing, nobody doubts that.

But just because the placebo effect occasionally delivers unexpected outcomes doesn't mean we should overestimate how powerful it is – nor try to find a place for it in the medical care of patients, scientists are now warning.

In a new perspective article, researchers argue that recent suggestions placebos could play a role in clinical care are unfounded, and are based on flawed evidence.

Much of the current discourse on placebo seems to focus more on enshrining placebos as mysterious and highly effective and less on making a practical difference to patient care and outcomes.

Observations of the placebo effect can be traced back to the 18th century, and the reputation of the placebo has grown ever since: the idea that an inert, sham treatment, taken unknowingly by a patient, can sometimes deliver therapeutic effects like the real thing.

That reputation is mostly underserved. A Cochrane review of placebos considered 234 trials and concluded that, in general, placebos do not produce major health benefits, except for some small and inconsistent effects on self-reported outcomes such as pain or nausea," the researchers explain.

Placebos remain important for clinical trials because they help achieve blinding and, thus, control of bias," the team writes.

"When administered in a blinded fashion, a placebo will provide a small effect, but the real treatment will normally provide better outcomes for the patient… It may be better to dismiss placebos and instead manage patients with evidence-based treatments., they conclude.

https://onlinelibrary.wiley.com/doi/10.5694/mja2.51230

https://www.sciencealert.com/the-placebo-effect-is-an-amazing-illus...

Serious Infections Linked to Autism: Study

In both a mouse model and the hospital records of more than 3 million children, researchers found a connection between strong immune activation in males and later symptoms of autism spectrum disorder.

While researchers have found plenty of gene variants that seem to increase the risk of an autism diagnosis, it’s not clear why some people carrying these mutations develop autism spectrum disorders and some do not. In a study published today (September 17) in Science Advances, researchers point to a potential answer: severe infections during early childhood. After an early immune challenge, male mice with a mutated copy of the tuberous sclerosis complex 2 (Tsc2) gene developed deficits in social behavior linked to changes in microglia, the immune cells of the brain. And an analysis of the hospital records of more than 3 million children showed that children, particularly boys, who were hospitalized for infections between ages 18 months and four years were more likely that healthy peers to receive a future autism spectrum disorder (ASD) diagnosis.

https://www.science.org/doi/10.1126/sciadv.abf2073

https://www.the-scientist.com/news-opinion/serious-infections-linke...

Inhibiting targets of SARS-CoV-2 proteases can block infection, study shows

Researchers  have shown how SARS-CoV-2 viral proteases attack the host cell, and how this can be targeted to stop virus replication in cell culture using existing drugs.

The new findings, published today in Nature Communications, offer a powerful resource to understand proteolysis in the context of viral infection, and to inform the development of targeted strategies to inhibit the virus that causes COVID-19.

Both viral and cellular proteases play a crucial role in SARS-CoV-2 replication, and inhibitors targeting proteases have already shown success at inhibiting SARS-CoV-2 in cell culture models. 

In this study, researchers used a mass spectrometry approach to study proteolytic cleavage events during SARS-CoV-2 infection.

The team found previously unknown cleavage sites in multiple viral proteins, including major antigenic proteins S and N, which are the main targets for vaccine and antibody testing efforts.

They discovered significant increases in cellular cleavage events consistent with cleavage by SARS-CoV-2 main protease (Mpro) and identified 14 potential high-confidence substrates of the main and papain-like proteases, validating a subset with in vitro assays.

They went on to show that siRNA depletion of these cellular proteins inhibits SARS-CoV-2 replication, and that drugs targeting two of these proteins: the tyrosine kinase SRC and Ser/Thr kinase MYLK, showed a dose-dependent reduction in SARS CoV-2 titres.

Both Bafetinib (an experimental cancer drug) and Sorafenib (an approved drug used to treat kidney and liver cancer) showed SARS-CoV-2 inhibition at concentrations that did not result in cytotoxicity in a human cell line model of infection.

Characterising proteolysis during SARS-CoV-2 infection identifies viral cleavage sites and cellular targets with therapeutic potential, Nature Communications (2021). DOI: 10.1038/s41467-021-25796-w

https://phys.org/news/2021-09-inhibiting-sars-cov-proteases-block-i...

Rock shape should be given greater consideration in rockfall risk assessments

The shape of rocks is a key factor in assessing rockfall hazard. This is the conclusion of a new study from the Institute for Snow and Avalanche Research.

Rockfall is a very real threat in an Alpine country like Switzerland. In order to assess the hazard at a given location and plan protective measures, engineering firms use computer models to calculate how far falling rocks can roll. However, the models are not yet able to adequately take into account the extent to which the mass, size or shape of a rock influences its movement. This would require real-world measurement data to be fed into the models, but until now such data were only available sporadically, since no systematic rockfall studies had been conducted.

First comprehensive experiments

That has now changed after researchers  spent over four years carrying out rockfall experiments. This has allowed them to compile the largest set of measurement data to date.

The researchers used artificial rocks in the form of concrete blocks fitted with sensors, which they rolled down a slope near the Flüela Pass in the Swiss canton of Grisons. They compared different shapes and masses, reconstructed the complete trajectories and determined speeds, jump heights and runout zones (see info box). They have just published their results in the scientific journal Nature Communications.

The most significant finding is that the direction a rock rolls in depends much more on its shape than on its mass. While cube-shaped boulders plunge straight down the line of greatest slope, wheel-shaped rocks often pull away to one side and so may threaten a much wider area at the base of the slope. "This needs to be taken into consideration when assessing danger zones, but also when determining the location and dimensions of rockfall nets.

Because wheel-like rocks hit rockfall nets with their narrow side, their energy is concentrated on a much smaller area than is the case with cube-like rocks—so protective nets need to be stronger.

The data set is also available on the EnviDat platform, where it is freely accessible to other research groups. They can use it to calibrate their own algorithms or to develop new, more accurate models providing enhanced protection against rockfall.

Andrin Caviezel et al, The relevance of rock shape over mass—implications for rockfall hazard assessments, Nature Communications (2021). DOI: 10.1038/s41467-021-25794-y

https://phys.org/news/2021-09-greater-consideration-rockfall.html?u...

Satellite swarms may outshine the night sky’s natural constellations

“Mega-constellations” from those satellites will be visible to the naked eye, simulations suggest

A few years back  somebody asked me from the art field, "If You 're asked to make a science-art installation, what would it be?" My instant answer was, "Groups of satellites in the night sky that shine like star constellations and also help the mankind". 

"Wow!" was that person's reaction.

But,  now that reply of mine is going to be revisited. Why? Companies like SpaceX and Amazon have launched hundreds of satellites into low orbits since 2019, with plans to launch thousands more in the works — a trend that’s alarming astronomers. The goal of these satellite “mega-constellations” is to bring high-speed internet around the globe, but these bright objects threaten to disrupt astronomers’ ability to observe the cosmos.

 Now, a new simulation of the potential positions and brightness of these satellites shows that, contrary to earlier predictions, casual sky watchers will have their view disrupted, too. And parts of the world will be affected more than others.

Flat, smooth surfaces on satellites can reflect sunlight depending on their position in the sky. Earlier research had suggested that most of the new satellites would not be visible with the naked eye.

There are currently about 7,890 objects in Earth orbit, about half of which are operational satellites, according to the U.N. Office for Outer Space Affairs. But that number is increasing fast as companies launch more and more satellites . In August 2020, there were only about 2,890 operational satellites.

Part1

the researchers computed how many satellites will be in the sky at different times of year, at different hours of the night and from different positions on Earth’s surface. They also estimated how bright the satellites were likely to be at different hours of the day and times of the year.

The simulations showed that “the way the night sky is going to change will not affect all places equally,” Lawler says. The places where naked-eye stargazing will be most affected are at latitudes 50° N and 50° S, regions that cross lower Canada, much of Europe, Kazakhstan and Mongolia, and the southern tips of Chile and Argentina, the researchers found.

The geometry of sunlight in the summer means there will be hundreds of visible satellites all night long. It’s bad everywhere, but it’s worse there.

--

A few visible satellites can be a fun spectacle. Astronomers have been meeting with representatives from private companies, as well as space lawyers and government officials, to work out compromises and mitigation strategies. Companies have been testing ways to reduce reflectivity, like shading the satellites with a “visor.” Other proposed strategies include limiting the satellites to lower orbits, where they move faster across the sky and leave a fainter streak in telescope images. Counterintuitively, lower satellites may be better for some astronomy research. “They move out of the way quick.”

But that lower altitude strategy will mean more visible satellites for other parts of the world, and more that are visible to the naked eye.

There are some latitudes on Earth where no matter what altitude you put your satellites at, they’re going to be all over the darn place. The only way out of this is fewer satellites.

There are currently no regulations concerning how bright a satellite can be or how many satellites a private company can launch. Scientists are grateful that companies are willing to work with them, but think that their cooperation is voluntary. Efforts are under way to bring the issue to the attention of the United Nations and to try to use existing environmental regulations to place limits on satellite launches.

S. Lawler, A. Boley and H. Rein. Visibility predictions for near-future satellite megaconstellations.... arXiv:2109.04328. Posted September 9, 2021.

https://www.sciencenews.org/article/satellite-mega-constellations-n...

Salty Diet Helps Gut Bugs Fight Cancer in Mice: Study

Brain-Eating Amoeba

Infants have more microplastics in their feces than adults, study finds

Microplastics—tiny plastic pieces less than 5 mm in size—are everywhere, from indoor dust to food to bottled water. So it's not surprising that scientists have detected these particles in the feces of people and pets. Now, in a small pilot study, researchers reporting in ACS' Environmental Science & Technology Letters discovered that infants have higher amounts of one type of microplastic in their stool than adults. Health effects, if any, are uncertain.

Little is known about the magnitude of human exposure to microplastics or their health effects. Although microplastics were once thought to pass harmlessly through the gastrointestinal tract and exit the body, recent studies suggest that the tiniest pieces can cross cell membranes and enter the circulation. In cells and laboratory animals, microplastic exposure can cause cell death, inflammation and metabolic disorders.

The researchers used mass spectrometry to determine the concentrations of PET and PC microplastics in six infant and 10 adult feces samples collected from New York state, as well as in three samples of meconium (a newborn infant's first stool). All samples contained at least one type of microplastic. Although average levels of fecal PC microplastics were similar between adults and infants, infant stool contained, on average, more than 10 times higher PET concentrations than that of adults.

Infants could be exposed to higher levels of microplastics through their extensive use of products such as bottles, teethers and toys, the researchers say.

Occurrence of Polyethylene Terephthalate and Polycarbonate Microplastics in Infant and Adult Feces, Environmental Science & Technology Letters (2021). pubs.acs.org/doi/abs/10.1021/acs.estlett.1c00559

https://phys.org/news/2021-09-infants-microplastics-feces-adults.ht...

Global cancer risk from burning organic matter comes from unregulated chemicals

Whenever organic matter is burned, such as in a wildfire, a power plant, a car's exhaust, or in daily cooking, the combustion releases polycyclic aromatic hydrocarbons (PAHs)—a class of pollutants that is known to cause lung cancer.

There are more than 100 known types of PAH compounds emitted daily into the atmosphere. Regulators, however, have historically relied on measurements of a single compound, benzo(a)pyrene, to gauge a community's risk of developing cancer from PAH exposure. Now MIT scientists have found that benzo(a)pyrene may be a poor indicator of this type of cancer risk.

In a modeling study appearing today in the journal GeoHealth, the team reports that benzo(a)pyrene plays a small part—about 11 percent—in the global risk of developing PAH-associated cancer. Instead, 89 percent of that cancer risk comes from other PAH compounds, many of which are not directly regulated.

Interestingly, about 17 percent of PAH-associated cancer risk comes from "degradation products"—chemicals that are formed when emitted PAHs react in the atmosphere. Many of these degradation products can in fact be more toxic than the emitted PAH from which they formed.

Jamie M. Kelly et al, Global Cancer Risk from Unregulated Polycyclic Aromatic Hydrocarbons, GeoHealth (2021). DOI: 10.1029/2021GH000401

https://phys.org/news/2021-09-global-cancer-unregulated-chemicals.h...

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Flying cars

Hairdressers say people are having allergic reactions to hair dye due to COVID

Covid-19: New allergic reactions to hair dye reported

The Roman Space Telescope's Wide Field Instrument

Winged microchip is smallest-ever human-made flying structure

Inspired by the way trees like maples disperse their seeds using little more than a stiff breeze, researchers developed a range of tiny flying microchips, the smallest one hardly bigger than a grain of sand.

This flying microchip or 'microflier' catches wind and spins like a helicopter towards the ground.

The microfliers can be packed with ultra-miniaturized technology, including sensors, power sources, antennas for wireless communication, and even embedded memory for data storage.

Reprogramming heart muscle cells to repair damage from heart attacks

A team of researchers has found that it is possible to reprogram heart muscle to repair damaged tissue. In their paper published in the journal Science, the group describes their approach to repairing damaged hearts in mice and how well it worked when tested.

There are two main kinds of heart attack. The first occurs when something prevents the heart from beating. The second occurs when blood flow is restricted to parts of the heart, preventing the muscle in that area from beating. The first kind is generally fatal unless the heart can be restarted very quickly. The second is generally less serious, but can leave permanent, debilitating scarring. In this new effort, the researchers have found a way to prevent such scarring—at least in mice.

The work built on prior research that showed that in the case of a baby experiencing heart damage in utero, the heart can repair itself because the cardiomyocyte cells are in a state that allows rejuvenation. This is not the case after birth or later in life, as the cardiomyocytes have no ability to regenerate. After several years of effort, the researchers discovered a way to get adult cardiomyocytes to revert back to fetal-like cardiomyocytes by reprogramming them using the Yamanaka factors c-Myc, Klf4, Sox2 and Oct4. Their research showed that such factors express for cell renewal. The reprogramming also featured an on/off switch using the antibiotic doxycycline. 

The researchers then tested their approach by giving mice with reprogrammed cells doxycycline just prior to and after inducing heart damage. They found that under both scenarios, heart regeneration occurred along with heart function improvement. The researchers also tried giving similar test mice doxycycline six days after experiencing heart damage and found it had no impact. Thus, the window of repair is short. Further testing also showed that if doxycycline was administered for too long a period, cancerous tumors developed. Much more work is required to determine if a similar approach might work for humans, and if it can be done without increasing the risk of cancer.

Yanpu Chen et al, Reversible reprogramming of cardiomyocytes to a fetal state drives heart regeneration in mice, Science (2021). DOI: 10.1126/science.abg5159

https://medicalxpress.com/news/2021-09-reprogramming-heart-muscle-c...

Scientists suggest pregnant women only take paracetamol/acetaminophen only if medically necessary

A group of 13 scientists has penned a consensus statement regarding the use of paracetamol/acetaminophen (APAP) by pregnant women. In their paper, published in the journal Nature Reviews Endocrinology, the group suggests that pregnant women only take paracetamol/acetaminophen only if it is medically necessary. Nature has also published an Editorial in the same journal issue, outlining the consensus statement and noting that its authors are not calling for a ban on the drug being used, instead they are suggesting that it be taken more cautiously by pregnant women because of a possible risk of birth defects.

In their paper, the authors note that research over the past several years has shown that it is possible under some circumstances for APAP to alter fetal development which in some cases can lead to problems with neurological, urological and reproductive disorders in the baby—they looked at 29 studies and found evidence of birth defects in 26 of them. They call for more research to be conducted to better understand possible problems with the drug being used by pregnant women. They also acknowledge—as do several experts in a reaction piece published on the Science Media Centre, site—that APAP is the only drug currently available for pain management for pregnant women. And they point out that medical use of APAP is generally warranted when the mother experiences problems that can negatively impact her baby—such as having a fever. But they also note that use of APAP by pregnant women appears to have crept up into general use as it has gained a reputation as being safe to use as an all-purpose analgesic.

The authors of the consensus statement further suggest that their intent in publishing such an article is to bring renewed and more focused attention to the possibility of APAP use leading to certain birth defects and the conditions under which they might arise. They note that current research has shown, for example, that the possibility of harm seems to increase as the duration of APAP use goes up. Thus, they suggest pregnant women consider using the drug for short term pain management, rather than as a long-term solution.

Ann Z. Bauer et al, Paracetamol use during pregnancy—a call for precautionary action, Nature Reviews Endocrinology (2021). DOI: 10.1038/s41574-021-00553-7

https://medicalxpress.com/news/2021-09-scientists-pregnant-women-pa...

How do cells react when a chromosome is lost?

Human cells are usually diploid—they contain two sets of chromosome. Cells in which one chromosome is missing from the duplicated chromosome set are generally not viable. For a long time, the mechanisms responsible for the loss of viability were unknown. New research now throws some light on it.

Monosomy occurs when chromosomes are incorrectly distributed during routine cell division and cells subsequently lack one chromosome in an otherwise double (diploid) set. The only form of this deviation in chromosome number (aneuploidy) that human cells can survive is known as Turner syndrome. The hallmark of the hereditary disease, which occurs in women: only one of the two X sex chromosomes is present. However, what happens in human somatic cells that are missing other than sex chromosome had not been explored until now, because monosomic cells are generally not viable.

When monosomy occurs, the protein 'p53," encoded by the so-called tumor suppressor gene TP53, ensures that the cell cycle stops. In other words, the cells stop dividing. Therefore, researchers have switched off this gene in one part of their cell lines, which were originally derived from human retina cell lines, to downregulate the production of the encoded protein. Thus, for the first time, they succeeded in generating stable monosomic cell lines for research purposes.

The research team subsequently focused on the effects of monosomy on proliferation (cell growth/multiplication), genomic stability and how chromosome loss affects the amount of mRNAs and proteins (transcriptome and proteome, respectively). They we observed reduced levels of cytoplasmic ribosomal proteins and reduced protein synthesis (protein translation) in all monosomal cell lines. Accordingly, they hypothesize that chromosome loss impairs ribosomal biogenesis and thereby cellular proliferation. They also showed that this change triggers cell cycle arrest and or senescence via the p53 signaling pathway.

The findings also shed light on the link between cancer and monosomy. Recurrent loss of an entire chromosome or chromosome arm is common in certain tumors, such as neuroblastoma, lung cancer, and myeloid malignancies.

Since monosomies are viable only without p53, scientists predicted that the cancers with monosomy must have defective p53 pathway. The analysis of scientific databases of cancer-related changes, such as "The Cancer Genome Atlas (TCGA)' and "Cancer Cell Lines Encyclopedia (CCLE)", indeed revealed a strong association of monosomy with p53 inactivation and ribosomal pathway impairment.

Narendra Kumar Chunduri et al, Systems approaches identify the consequences of monosomy in somatic human cells, Nature Communications (2021). DOI: 10.1038/s41467-021-25288-x

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Part 1

The research team also performed a systematic transcriptome and proteome analysis of monosomic cell lines in comparison to their parental cell lines—i.e., the quantification of all messenger RNAs (mRNAs) transcribed based on DNA, as well as the quantification of all proteins in the cells. As expected, this showed that the expression of genes localized on the monosome was reduced. 

Yet, teh researchers observed the lower levels in only 20 percent of the encoded proteins. They suspect that gene dosage effects came into play here. The cells need to return to their 'natural' diploid protein levels to sustain their function and thus compensate for the chromosome loss. Scientists envision two possible scenarios: First, translation of mRNAs encoded using the genes could be selectively increased, or second, protein degradation is reduced. These results suggest that cells use multiple pathways to mitigate the consequences of altered gene expression.

In summary, these scientists present for the first time a successful experimental approach to study the effects of monosomy in human somatic cells.

https://phys.org/news/2021-09-chromosome-lost-human-cells-react.htm...

Part 2

A 3D printed vaccine patch offers vaccination without a shot

 Scientists have created a 3D-printed vaccine patch that provides greater protection than a typical vaccine shot. The trick is applying the vaccine patch directly to the skin, which is full of immune cells that vaccines target.

The resulting immune response from the vaccine patch was 10 times greater than vaccine delivered into an arm muscle with a needle jab, according to a study conducted in animals and published by the team of scientists in the Proceedings of the National Academy of Sciences.

Considered a breakthrough are the 3D-printed microneedles lined up on a polymer patch and barely long enough to reach the skin to deliver vaccine. The ease and effectiveness of a vaccine patch sets the course for a new way to deliver vaccines that's painless, less invasive than a shot with a needle and can be self-administered.

Study results show the vaccine patch generated a significant T-cell and antigen-specific antibody response that was 50 times greater than a subcutaneous injection delivered under the skin.

That heightened immune response could lead to dose sparing, with a microneedle vaccine patch using a smaller dose to generate a similar immune response as a vaccine delivered with a needle and syringe.

“Transdermal vaccination via 3D-printed microneedles induces potent humoral and cellular immunity” by Cassie Caudill, Jillian L. Perry, Kimon Iliadis, Addis T. Tessema, Brian J. Lee, Beverly S. Mecham, Shaomin Tian and Joseph M. DeSimone, 22 September 2021, Proceedings of the National Academy of Sciences.
DOI: 10.1073/pnas.2102595118

https://researchnews.cc/news/9101/A-3D-printed-vaccine-patch-offers...

AugLimb: Compact Robotic Limb for Human Augmentation

Melting of polar ice shifting Earth itself, not just sea levels

The melting of polar ice is not only shifting the levels of our oceans, it is changing the planet Earth itself. Researchers recently  explained in a paper in Geophysical Research Letters that, as glacial ice from Greenland, Antarctica, and the Arctic Islands melts, Earth's crust beneath these land masses warps, an impact that can be measured hundreds and perhaps thousands of miles away.

By analyzing  satellite data on melt from 2003 to 2018 and studying changes in Earth's crust,  researchers were able to measure the shifting of the crust horizontally. Their research, which was highlighted in Nature, found that in some places the crust was moving more horizontally than it was lifting. In addition to the surprising extent of its reach, the Nature brief pointed out, this research provides a potentially new way to monitor modern ice mass changes.

The implications of this movement are far-reaching. "Understanding all of the factors that cause movement of the crust is really important for a wide range of Earth science problems. For example, to accurately observe tectonic motions and earthquake activity, we need to be able to separate out this motion generated by modern-day ice-mass loss.

Sophie Coulson et al, The Global Fingerprint of Modern Ice‐Mass Loss on 3‐D Crustal Motion, Geophysical Research Letters (2021). DOI: 10.1029/2021GL095477

So much ice is melting that Earth's crust is moving, Nature (2021). DOI: 10.1038/d41586-021-02285-0

https://phys.org/news/2021-09-polar-ice-shifting-earth-sea.html?utm...

One more myth busted: Cavers find snakes but no genies in Yemen's 'Well of Hell'

A team of Omani cavers has made what is believed to be the first descent to the bottom of Yemen's fabled Well of Barhout—a natural wonder shunned by many locals, who believe it is a prison for genies.

The forbidding 'Well of Hell', whose dark, round aperture creates a 30-metre (100 foot) wide hole in the desert floor of Yemen's eastern province of Al-Mahra, plunges approximately 112 metres (367 feet) below the surface and, according to some accounts, gives off strange odours.
Inside, the Oman Cave Exploration Team (OCET) found snakes, dead animals and cave pearls—but no signs of the supernatural.
https://phys.org/news/2021-09-cavers-snakes-genies-yemen-hell.html?...

Scientists report starch synthesis from carbon dioxide

Scientists recently reported a de novo route for artificial starch synthesis from carbon dioxide (CO₂) for the first time.

The new route makes it possible to shift the mode of starch production from traditional agricultural planting to industrial manufacturing, and opens up a new technical route for synthesizing complex molecules from CO₂.

Starch is the major component of grain as well as an important industrial raw material. At present, it is mainly produced by crops such as maize by fixing CO₂ through photosynthesis. This process involves about 60 biochemical reactions as well as complex physiological regulation. The theoretical energy conversion efficiency of this process is only about 2%.

Strategies for the sustainable supply of starch and use of CO₂ are urgently needed to overcome major challenges of mankind, such as the food crisis and climate change. Designing novel routes other than plant photosynthesis for converting CO₂ to starch is an important and innovative S&T mission and will be a significant disruptive technology in today's world.

To address this issue, scientists at the Tianjin Institute of Industrial Biotechnology (TIB) of the Chinese Academy of Sciences (CAS) designed a chemoenzymatic system as well as an artificial starch anabolic route consisting of only 11 core reactions to convert CO₂ into starch.

This route was established by a "building block" strategy, in which the researchers integrated chemical and biological catalytic modules to utilize high-density energy and high-concentration CO₂ in a biotechnologically innovative way.

The researchers systematically optimized this hybrid system using spatial and temporal segregation by addressing issues such as substrate competition, product inhibition, and thermodynamical adaptation.

The artificial route can produce starch from CO₂ with an efficiency 8.5-fold higher than starch biosynthesis in maize, suggesting a big step towards going beyond nature. It provides a new scientific basis for creating biological systems with unprecedented functions.

This work would open a window for industrial manufacturing of starch from CO₂.

If the overall cost of the process can be reduced to a level economically comparable with agricultural planting in the future, it is expected to save more than 90% of cultivated land and freshwater resources. In addition, it would also help to avoid the negative environmental impact of using pesticides and fertilizers, improve human food security, facilitate a carbon-neutral bioeconomy, and eventually promote the formation of a sustainable bio-based society.

Cai Tao et al, Cell-free chemoenzymatic starch synthesis from carbon dioxide, Science (2021). DOI: 10.1126/science.abh4049

https://phys.org/news/2021-09-chinese-scientists-starch-synthesis-c...

The Common Kitchen Ingredient That Could Help if Your Child Swallows a Battery

Every day, and thousands of times a year, a kid swallows a battery.

In the last 20 years or so, this dangerous and sometimes fatal accident has actually become significantly more common in children, and severe injuries caused by button battery ingestion (BBI) have led to a marked increase in hospitalizations.

Thankfully, in most such cases the item ends up passing harmlessly through the patient's digestive tract. However, even tiny batteries can cause tremendous damage if they get stuck in the esophagus.

Young children up to six years of age are most at risk of BBI complications due to their smaller body size, which increases the chance that a swallowed battery might get lodged in their esophagus – especially larger button batteries such as the ubiquitous 20-millimeter CR2032, used in a vast range of small electronics.

Within just two hours, a stuck battery can cause severe burns as its negatively charged surface makes prolonged contact with the conductive tissue of the esophagus; this contact produces an electrical current and breaks nearby water down into a highly corrosive fluid.

If this happens to your child – or you suspect your young, non-verbal child might have swallowed a battery – do not delay. Seek immediate medical attention, as a lodged battery could require urgent endoscopic removal.

However, while you're waiting for medical assistance, researchers now say there is something you can do yourself to mitigate the risk of tissue injury – and it makes use of a condiment many of us have in our kitchens.

According to a newly published research summary on BBI events and complications, honey may help when administered before the patient reaches the hospital, given at 10 milliliters every 10 minutes for children older than one year (up to six doses).

That recommendation is based on a study published in 2018, which explored injury mitigation from button battery blockages in the esophagus using an animal model of young pigs.

In the experiment, researchers tested a range of different household liquids (including honey, maple syrup, Gatorade, and fruit juices) to see whether any of them helped minimize tissue injury resulting from battery lodgment in the animal's esophagus.

Ultimately, two liquids produced the most clinically optimal results: honey, and a product called Carafate, (brand-name version of the medication sucralfate), which is used to treat ulcers and other stomach conditions.

"In the crucial period between button battery ingestion and endoscopic removal, early and frequent ingestion of honey in the household setting and Carafate in the clinical setting has the potential to reduce injury severity and improve patient outcomes.

https://onlinelibrary.wiley.com/doi/epdf/10.1002/lary.27312

https://www.sciencealert.com/the-common-kitchen-ingredient-that-cou...

Aspirin and Birth Defects: Fetal Cell Inhibition — Science News, October 2, 1971

Although aspirin has triggered defects in rat and mice fetuses, the evidence suggesting aspirin taken by women during pregnancy can harm their offspring has been circumstantial at best. Now, however … [evidence shows] that aspirin can dramatically arrest the growth of human embryo cells.

Part 1

Update

Scientists are still sorting out how aspirin and other nonsteroidal anti-inflammatory drugs, collectively known as NSAIDs, affect pregnancy at every stage. Taking NSAIDs during the first trimester is known to increase the risk of miscarriage . In 2020, the U.S. Food and Drug Administration warned that people who are 20 weeks or more into a pregnancy should avoid using NSAIDs altogether because the drugs can cause rare but serious kidney problems as well as heart problems for fetuses. However, exceptions can be made for pregnant people at risk of preeclampsia , clotting and preterm delivery. In such cases, the FDA recommends that doctors prescribe the lowest effective dose of aspirin.

https://www.sciencenews.org/article/50-years-ago-scientists-found-l...

Part 2

Unbelievable DRONE display - Guinness World Records

The longest animation performed by unmanned aerial vehicles (UAVs) is 26 min 19 sec and was achieved by EFYI Group (China) and supported by Tianjin University (China) in Tianjin, China, on 18 December 2020. They depicted the life of Dutch artist Vincent Van Gogh.

Making Music from Proteins

Researchers reporting in ACS Nano have found a way to represent a protein’s structure as music.

A Self-Consistent Sonification Method to Translate Amino Acid Sequences into Musical Compositions and Application in Protein Design using Artificial Intelligence.

How mercury gets into the sea

Mercury released into the atmosphere by industry enters the sea and from there makes its way into the food chain. Now, an analysis by researchers has revealed how the harmful substance enters seawater in the first place. This is not primarily via rainfall, as previously assumed, but rather also involves gas exchange. Measures to reduce mercury emissions could therefore take effect faster than previously thought.

Every year, 2,000 metric tons of gaseous mercury are released into the atmosphere by coal-fired power stations and mining activities. The harmful substance then adopts various chemical forms as it circulates between the air, soil and water in a complex cycle. Mercury is particularly dangerous in the sea, where it accumulates in fish in the form of highly toxic methylmercury. When this compound enters the human body due to the consumption of fish, it can have an adverse effect on brain development in children and cause cardiovascular diseases in adults.

It's estimated that human activities have tripled the amount of mercury in the surface ocean  since the onset of industrialization. Those are just assumptions, however, as there are no collector stations for precipitation over the sea.

The gap was closed by analyzing seawater samples using a new method that allows researchers to distinguish whether mercury originates from precipitation or entered the sea via gas exchange, . Known as "fingerprinting," this technique is based on the measurement of tiny weight differences between naturally occurring mercury atoms, known as isotopes.

The analyses revealed that—contrary to previous assumptions—only about half of the mercury in the sea originates from precipitation, while the other half enters the oceans due to the uptake of gaseous mercury.

Researchers suspect  that mercury uptake by plants drives more of the heavy metal to be deposited on land, where it is safely sequestered in soils and poses less of a risk to humans.

The new findings are also important for the implementation of the Minamata Convention of 2013, whereby 133 countries committed to reducing mercury emissions: "If less mercury enters the sea via rainfall, a reduction in emissions could cause mercury levels in seawater to drop faster than anticipated."

Mercury stable isotopes constrain atmospheric sources to the Ocean, Nature (2021). DOI: 10.1038/s41586-021-03859-8 , www.nature.com/articles/s41586-021-03859-8

https://phys.org/news/2021-09-mercury-sea.html?utm_source=nwletter&...

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Breath tests could sniff out COVID-19

Since May 2021, drivers crossing into Singapore at the Tuas Checkpoint have been required to breathe into a cigar-sized mouthpiece connected to a mass spectrometer. In less than a minute, the device analyzes the breath samples for COVID-19. According to a new feature article in Chemical & Engineering News, such breath-based diagnostics might be a fast, cheap way to detect infection, although challenges exist.

More than a year into the pandemic, PCR-based assays—which require samples to be collected from patients' nasal passages with a long cotton swab—remain the gold standard for COVID-19 diagnosis. However, such tests are uncomfortable, slow and relatively expensive.

That's why several companies have launched breathalyzer-like tests to detect SARS-CoV-2 infection. These tests rely on altered ratios of volatile organic compounds (VOCs) in exhaled breath, which reflect metabolic changes triggered by the virus. But questions about whether the technology is sufficiently sensitive and reproducible are still unanswered. 

One challenge is that researchers haven't sufficiently defined the levels of VOCs in the breath of healthy people, which makes it difficult to accurately measure when someone's exhalation deviates from the norm. As a result, some breath-based tests have had disappointing results when used in real life. Also, some VOCs change similarly in response to different viruses or conditions, making it important to identify unique patterns or ratios of biomarkers that change only upon infection with SARS-CoV-2. Scientists in the field are hopeful that continued standardization and validation will eventually create a robust breath-based diagnostic that might even be able to detect infection earlier than PCR-based tests, before a person begins shedding the virus.

https://phys.org/news/2021-09-covid-.html?utm_source=nwletter&u...

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Toxic DNA buildup in eyes may drive blinding macular degeneration

Common HIV drugs could stop vision loss, research suggests

Damaging DNA builds up in the eyes of patients with geographic atrophy, an untreatable, poorly understood form of age-related macular degeneration that causes blindness, new research reveals. Based on the discovery, the researchers think it may be possible to treat the disease with common HIV drugs or an even safer alternative.

Geographic atrophy is an advanced form of age-related macular degeneration, a potentially blinding disease estimated to affect 200 million people around the world. The disease ultimately destroys vital cells in the retina, the light-sensing portion of the eye

A harmful DNA, known as Alu cDNA, was previously discovered to be manufactured in the cytoplasm. The new findings offer insights into how geographic atrophy progresses over time. This finding in human eyes that the levels of toxic Alu cDNA are highest at the leading edge of the geographic atrophy lesion provides strong evidence that it is responsible for this expansion over time that leads to vision loss.

As Alu DNA accumulates in the eye, it triggers harmful inflammation via a part of the immune system called the inflammasome. The researchers identified how this happens, discovering a previously unknown structural facet of Alu that triggers the immune mechanism that leads to the death of the vital retinal cells.

That's where HIV drugs called nucleoside reverse transcriptase inhibitors, or NRTIs, could come in. The researchers' new work in lab mice suggests these drugs, or safer derivatives known as Kamuvudines, could block the harmful inflammation and protect against retinal cell death.

Alu complementary DNA is enriched in atrophic macular degeneration and triggers retinal pigmented epithelium toxicity via cytosolic innate immunity. Science Advances, 2021; 7 (40) DOI: 10.1126/sciadv.abj3658

https://www.sciencedaily.com/releases/2021/09/210930101425.htm

Study unveils the quantum nature of the interaction between photons and free electrons

For several decades, physicists have known that light can be described simultaneously as a wave and a particle. This fascinating 'duality' of light is due to the classical and quantum nature of electromagnetic excitations, the processes through which electromagnetic fields are produced.

So far, in all experiments in which light interacts with free electrons, it has been described as a wave. Researchers at Technion—Israel Institute of Technology, however, have recently gathered the first experimental evidence revealing the quantum nature of the interaction between photons and free electrons. Their findings, published in Science, could have important implications for future research investigating photons and their interaction with free electrons.

Raphael Dahan et al, Imprinting the quantum statistics of photons on free electrons, Science (2021). DOI: 10.1126/science.abj7128

Ofer Kfir, Entanglements of Electrons and Cavity Photons in the Strong-Coupling Regime, Physical Review Letters (2019). DOI: 10.1103/PhysRevLett.123.103602

Valerio Di Giulio et al, Probing quantum optical excitations with fast electrons, Optica (2019). DOI: 10.1364/OPTICA.6.001524

https://phys.org/news/2021-09-unveils-quantum-nature-interaction-ph...

How complex thoughts take place in the brain

Understanding how the human brain produces complex thought is daunting given its intricacy and scale. The brain contains approximately 100 billion neurons that coordinate activity through 100 trillion connections, and those connections are organized into networks that are often similar from one person to the next. A Dartmouth study has found a new way to look at brain networks using the mathematical notion of fractals, to convey communication patterns between different brain regions as people listened to a short story. The results are published in Nature Communications.

To generate our thoughts, our brains create  amazing lightning storm of connection patterns. The patterns look beautiful, but they are also incredibly complicated. Our mathematical framework lets us quantify how those patterns relate at different scales, and how they change over time.

In the field of geometry, fractals are shapes that appear similar at different scales. Within a fractal, shapes and patterns are repeated in an infinite cascade, such as spirals comprised of smaller spirals that are in turn comprised of still-smaller spirals, and so on. Dartmouth's study shows that brain networks organize in a similar way: patterns of brain interactions are mirrored simultaneously at different scales. When people engage in complex thoughts, their networks seem to spontaneously organize into fractal-like patterns. When those thoughts are disrupted, the fractal patterns become scrambled and lose their integrity.

The researchers developed a mathematical framework that identifies similarities in network interactions at different scales or "orders." When brain structures do not exhibit any consistent patterns of interaction, the team referred to this as a "zero-order" pattern. When individual pairs of brain structures interact, this is called a "first-order" pattern. "Second-order" patterns refer to similar patterns of interactions in different sets of brain structures, at different scales. When patterns of interaction become fractal— "first-order" or higher— the order denotes the number of times the patterns are repeated at different scales.

The study shows that when people listened to an audio recording of a 10-minute story, their brain networks spontaneously organized into fourth-order network patterns. However, this organization was disrupted when people listened to altered versions of the recording. For instance, when the story's paragraphs were randomly shuffled, preserving some but not all of the story's meaning, people's brain networks displayed only second-order patterns. When every word of the story was shuffled, this disrupted all but the lowest level (zero-order) patterns.

Part 1