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Comment by Dr. Krishna Kumari Challa on February 17, 2023 at 11:23am

Nanoparticles perform ultralong distance communication, have 'no counterpart or analogue in nature'

Chemists have designed a new photonic lattice with properties never before seen in nature. In solid materials, atoms must be equally spaced apart and close enough together to interact effectively. Now, new architectures based on stacked lattices of nanoparticles show interactions across unprecedentedly large distances.

When one lattice is stacked on top of the other, the nanoparticles can still interact with each other—even when the vertical separation among particles is 1,000 times the distance of the particle-to-particle spacing within the horizontal plane.

Because the nanoparticles can communicate across ultralong distances, the stacked architecture offers potential applications in remote sensing and detection.

This type of long-range coupling has not been observed before for any stacked periodic material. Other electronic or photonic stacked layers are separated vertically by a spacing similar to the horizontal periodicity of the building unit in the single layer. This is an entirely new class of engineered materials that have no counterpart or analogue in nature.

Jun Guan et al, Far-field coupling between moiré photonic lattices, Nature Nanotechnology (2023). DOI: 10.1038/s41565-023-01320-7

Comment by Dr. Krishna Kumari Challa on February 17, 2023 at 9:59am

Novel method to accurately measure key marker of biological aging

Telomeres—the caps at the ends of chromosomes that protect our genetic materials from the brunt of cellular wear and tear—are known to shorten and fray over time. Lifestyle, diet and stress can exacerbate this process, leading to early loss of telomere protection and increasing the chances of early aging and diseases, such as cancer and heart disease.

To date, approaches for measuring biological aging based on telomere length have been limited as they can only ascertain average telomere lengths within a pool of DNA fragments, or they are time-consuming and require highly-skilled specialists. Being able to accurately and efficiently measure the length of an individual's telomeres could open the doors to developing lifestyle interventions that slow aging and prevent disease.

Scientists have recently devised a way to rapidly and precisely measure the length of a single telomere.

They applied a novel approach that uses DNA sequences—they call them 'telobaits'—to latch onto the ends of telomeres in large pools of DNA fragments, like fishing in pond. Then, with specific scissor-like enzymes, they snip the telomeres out of the pools.

Using high-throughput genetic sequencing technology, they were able to read the DNA 'letters' that comprised each individual telomere, allowing them to very precisely measure their lengths.

The team successfully validated this approach when they tested it using human cell lines and patient cells. Interestingly, the sequencing results revealed that the genetic sequences within certain parts of the telomeres, known as telomeric variant sequences, were distinct to each individual person.

The researchers think this new approach could be used as a predictive biomarker for human aging and disease at the individual level, as well as for population-level studies on the impacts of lifestyle, diet and the environment on human health.

Cheng-Yong Tham et al, High-throughput telomere length measurement at nucleotide resolution using the PacBio high fidelity sequencing platform, Nature Communications (2023). DOI: 10.1038/s41467-023-35823-7

Comment by Dr. Krishna Kumari Challa on February 17, 2023 at 9:48am

Next, in a series of experiments, the researchers demonstrated that the aggression-mirroring neurons not only sensed aggression but enabled it. When they selectively inhibited these neurons, mice were less irked by a male intruder—and initiated only a third as many attacks or tail-rattles as normal mice.

Inversely, when the mirror neurons were switched on, the mice became indiscriminately aggressive. Not only did they initiate three times more attacks on male intruders than usual, they attacked even female visitors, who normally would have prompted frisky coupling behavior. Needless to say, they were less successful in mating. The male mice were so riled up they even tail-rattled at their own mirror reflection.

It tells you that the activity of these neurons is sufficient for aggression, even when there's no provocation. 

The fact that aggression-mirroring neurons exist in such a primitive part of the brain indicates they may have been conserved across evolution, from mouse to human. It suggests that we might have the same neurons, and maybe they encode some qualities of aggression in ourselves. 

The researchers did not investigate how observing aggressive behavior affected the observers, but they offer their own speculation—perhaps, like boxers studying videos of their opponent's moves, the mice on the sidelines learn to be better fighters.

Taehong Yang et al, Hypothalamic neurons that mirror aggression, Cell (2023). DOI: 10.1016/j.cell.2023.01.022

Part 2

Comment by Dr. Krishna Kumari Challa on February 17, 2023 at 9:46am

Scientists discover mirror neurons in mice and find they're tuned to aggression

In nature, when two animals fight, they are seldom without an audience. 

Researchers wanted to know how the animals on the sidelines perceive these aggressive interactions. In a new study in mice, they discovered that some neurons in a part of the brain known as the "rage center" fire both when a mouse is fighting and when it watches others fight. Such neurons are known as mirror neurons—they are active when an animal is doing the behaviour and when it's watching another animal do that same behaviour.

The study is the first to find mirror neurons in mice and in the hypothalamus—an evolutionarily ancient part of the brain—hinting at a more primal origin for mirror neurons than previously thought.

Aggression in the wild is rarely a private affair. Aggression is usually not only to defeat the other animal, but also to tell others in the vicinity, 'Hey, I'm the boss.' It's a public display. Previous work  traced aggression in male mice to a cluster of brain cells in a part of the ventromedial hypothalamus. (In female mice, the same neurons do not trigger aggression.) Dubbed the "rage center," these neurons could activate aggression, but also seemed sensitive to a mouse's socialization—communally housed mice were less aggressive. 

What else are these neurons sensitive to? Researchers proposed that these neurons might be sensitive to aggression between other mice.

And that turned out to be the case: They're mirroring aggression by other animals. 

Using precise imaging techniques, the researchers recorded activity in the rage center of male mice engaged in a brawl and those witnessing a fight.

Sparking a fight between male mice is simple—the researchers had only to introduce a male mouse into another's cage. The resident mouse would attack the intruder and display threatening behavior, like tail-rattling. To set up a witness, the researchers allowed a lone mouse to observe these fights through a transparent divider.

They found that a nearly identical set of neurons in the rage center were active in both fighters and observers—qualifying them as mirror neurons.

Another surprise was that in an observer, aggression-mirroring neurons were triggered by sight, whereas in fighting mice, they are triggered by the smell of pheromones. Video recordings revealed that mirror neurons fired only in the moments when the observer was facing the fighters, not when it was turned away. And when the researchers turned off the lights, the observer's mirror neurons were entirely unresponsive to the fracas next door.

The researchers found also that these mirror neurons seemed innately tuned to aggression, even in mice that had never witnessed or engaged in aggressive behavior. They did not fire when mice watched other behaviors, like sniffing, grooming or running on a wheel.

Part 1

Comment by Dr. Krishna Kumari Challa on February 16, 2023 at 12:09pm

The global toll of chicken and salmon

Farmed chicken and salmon are among the most sustainable meats available, but they still exert intense environmental pressures on the hotspots where farming.... The first study to map their impact on a global scale found that, by some metrics, chicken farming is more efficient than salmon farming: it yields 55 times more food per year because chickens grow to full size faster. But the study notes that marine wildlife disturbed by farming tend to recover, whereas habitats and species affected by farming on land generally don’t. And fishmeal that is used to make chicken feed is taken from the ocean, anyway.

https://www.cell.com/current-biology/fulltext/S0960-9822(23)00071-4?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0960982223000714%3Fshowall%3Dtrue

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Sleeping volcanoes leak more sulfur

Thanks to ‘passive degassing’ from dormant volcanoes, the atmosphere in pre-industrial times contained many more climate-cooling sulfur particles than we thought. Researchers examined Greenland ice cores to study the pristine Arctic atmosphere. They found that volcanoes are a major source of sulfur emissions, even during decades without major eruptions — in fact, dormant volcanoes belch out a lot more sulfur over those time spans than do active ones. Sulfate aerosols have a net cooling effect, but adding more gives diminishing returns. So, if natural levels are higher than we thought, we might have overest..., perhaps by as much as half.

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022GL102061?ut...

Comment by Dr. Krishna Kumari Challa on February 16, 2023 at 11:54am

Scientists find first evidence that black holes are the source of dark energy

Observations of supermassive black holes at the centers of galaxies point to a likely source of dark energy—the 'missing' 70% of the universe.

The measurements from ancient and dormant galaxies show black holes growing more than expected, aligning with a phenomenon predicted in Einstein's theory of gravity. The result potentially means nothing new has to be added to our picture of the universe to account for dark energy: black holes combined with Einstein's gravity are the source.

The conclusion was reached by a team of 17 researchers in nine countries, led by the University of Hawai'i and including Imperial College London and STFC RAL Space physicists. The work is published in two papers in the journals The Astrophysical Journal and The Astrophysical Journal Letters.

If the theory holds, then this is going to revolutionize the whole of cosmology, because at last we've got a solution for the origin of dark energy that's been perplexing cosmologists and theoretical physicists for more than 20 years.

Duncan Farrah et al, A Preferential Growth Channel for Supermassive Black Holes in Elliptical Galaxies at z ≲ 2, The Astrophysical Journal (2023). DOI: 10.3847/1538-4357/acac2e

The Astrophysical Journal Letters (2023). DOI: 10.3847/2041-8213/acb704. iopscience.iop.org/article/10. … 847/2041-8213/acb704

Comment by Dr. Krishna Kumari Challa on February 16, 2023 at 11:46am

Study: The faster El Niño decays, the fewer typhoons occur the following summer

As the largest climate signal on the interannual time scale, El Niño has pronounced impacts on typhoon activity. Recently, a growing number of studies have been focusing on the climatic effects of the pace of El Niño decay and the remarkable role this plays in the genesis position and intensity variations of typhoons. However, the response of the frequency of typhoon occurrence to the pace of El Niño decay remains unclear.

In a paper recently published in Atmospheric and Oceanic Science Letters, scientists attempted to address this issue. They present new evidence for variation in the pace of El Niño decay having a significant influence on the typhoon frequency in the summer following the mature winter of El Niño.

Firstly they classified El Niño cases into two categories: fast decaying [FD] and slow decaying [SD]. Interestingly, the typhoon occurrence frequency decreased sharply in the following summer only for FD El Niño cases. In order to explore the possible reason for this observed typhoon response, tehy further compared the environmental factors for typhoon development and the related atmospheric circulation processes between the FD and SD El Niño years.

Compared with those for SD El Niño years, fewer typhoons occurred in the following summer for FD El Niño years, and the causal mechanism was a stronger anticyclonic anomaly over the western North Pacific forced by tropical Indo-Pacific sea surface temperature (SST) anomalies. Therefore, the pace of El Niño decay might serve as an important factor in the prediction of typhoon activity.

However, the question of how these distinct patterns of tropical SST anomalies establish under FD and SD El Niño conditions needs to be studied in future work from the perspective of ocean dynamics.

Qun Zhou et al, Influence of the pace of El Niño decay on tropical cyclone frequency over the western north pacific during decaying El Niño summers, Atmospheric and Oceanic Science Letters (2023). DOI: 10.1016/j.aosl.2023.100328

Comment by Dr. Krishna Kumari Challa on February 16, 2023 at 11:32am

Discovering the magic in superconductivity's 'magic angle'

Researchers have produced new evidence of how graphene, when twisted to a precise angle, can become a superconductor, moving electricity with no loss of energy.

They reported on their finding of the key role that quantum geometry plays in allowing this twisted graphene to become a superconductor. 

Graphene is a single layer of carbon atoms, the lead that is found in a pencil.

In 2018, scientists at the Massachusetts Institute of Technology discovered that, under the right conditions, graphene could become a superconductor if one piece of graphene were laid on top of another piece and the layers were twisted to a specific angle—1.08 degrees—creating twisted bilayer graphene.

Ever since, scientists have been studying this twisted bilayer graphene and trying to figure out how this 'magic angle' works. The conventional theory of superconductivity doesn't work in this situation. so scientists  did a series of experiments to understand the origins of why this material is a superconductor. 

In a conventional metal, high-speed electrons are responsible for conductivity.

But twisted bilayer graphene has a type of electronic structure known as a "flat band" in which the electrons move very slowly—in fact at a speed that approaches zero if the angle is exactly at the magic one.

Under the conventional theory of superconductivity, electrons moving this slowly should not be able to conduct electricity.

With great precision the research group was able to obtain a device so close to the magic angle that the electrons were nearly stopped by usual condensed matter physics standards. The sample nevertheless showed superconductivity.

It is a paradox: How can electrons which move so slowly conduct electricity at all, let alone superconduct? It is very remarkable.

In their experiments, the research team demonstrated the slow speeds of the electrons and gave more precise measurements of electron movement than had been previously available.

And they also found the first clues as to what makes this graphene material so special.

They couldn't use the speed of electrons to explain how the twisted bilayer graphene is working. Instead, they had to use quantum geometry.

As with everything quantum, quantum geometry is complex and not intuitive. But the results of this study have to do with the fact that an electron is not only a particle, but also a wave—and thus has wavefunctions.

The geometry of the quantum wavefunctions in flat bands, together with the interaction between electrons, leads to the flow of electrical current without dissipation in bilayer graphene.

Their  experimental measurements suggest quantum geometry is 90% of what makes this a superconductor.

 Chun Lau, Evidence for Dirac flat band superconductivity enabled by quantum geometry, Nature (2023). DOI: 10.1038/s41586-022-05576-2. www.nature.com/articles/s41586-022-05576-2

Comment by Dr. Krishna Kumari Challa on February 16, 2023 at 10:44am

Food coloring and anti-caking nanoparticles may affect the human gut

Metal oxide nanoparticles—ubiquitous in nature, and commonly used as food coloring and anti-caking agents in the commercial ingredients industry—may damage and disturb parts of the human intestine, according to new research conducted by  scientists.

They  found that specific nanoparticles—titanium dioxide and silicon dioxide—ordinarily used in food may negatively affect intestinal functionality. They have a negative effect on key digestive and absorptive proteins. 

In their research, the group used human-relevant doses of titanium dioxide and silicon dioxide in the Tako laboratory's in vivo system, which offers a health response similar to the human body's.

The scientists injected the nanoparticles into chicken eggs. After the chickens hatched, the scientists detected changes in the functional, morphological and microbial biomarkers in the blood, the duodenum (upper intestine) and the cecum (a pouch connected to the intestine).

The scientists found shifts in the composition of intestinal bacterial populations. The animals' mineral transport was affected and the brush border membrane (the intestine's digestive and absorptive surface) was disturbed.

Additionally, the group examined zinc oxide, a micronutrient, and iron oxide, an iron fortification supplement. Zinc oxide nanoparticles support intestinal development, as well as a compensatory mechanism following intestinal damage. Iron oxide nanoparticles are a potential option for iron fortification, though with potential alterations in intestinal functionality and health.

The scientists are not advocating for ending the use of these nano particles.

Based on the information, they are suggesting to simply being aware. Science needs to conduct further investigations based on their findings. They are opening the door for discussion.

Jacquelyn Cheng et al, Food-Grade Metal Oxide Nanoparticles Exposure Alters Intestinal Microbial Populations, Brush Border Membrane Functionality and Morphology, In Vivo (Gallus gallus), Antioxidants (2023). DOI: 10.3390/antiox12020431

Comment by Dr. Krishna Kumari Challa on February 15, 2023 at 10:58am

Snakes can hear more than you think

A new  study has found that as well as ground vibrations, snakes can hear and react to airborne sound.

Because snakes don't have external ears, people typically think they're deaf and can only feel vibrations through the ground and into their bodies.

But this new research—the first of its kind using non-anesthetized, freely moving snakes—found they do react to soundwaves traveling through the air, and possibly human voices.

Researchers  played three different sound frequencies to captive-bred snakes one at a time in a soundproof room and observed their reactions. The study involved 19 snakes, representing five genetic families of reptile.

 They played one sound which produced ground vibrations, while the other two were airborne only. It meant researchers  were able to test both types of 'hearing'—tactile hearing through the snakes' belly scales and airborne through their internal ear.

The reactions strongly depended on the genus of the snakes.

Only the woma python tended to move toward sound, while taipans, brown snakes and especially death adders were all more likely to move away from it. The types of behavioral reactions also differed, with taipans in particular more likely to exhibit defensive and cautious responses to sound.

The different reactions are likely because of evolutionary pressures over millions of years, designed to aid survival and reproduction.

For example, woma pythons are large nocturnal snakes with fewer predators than smaller species and probably don't need to be as cautious, so they tended to approach sound. But taipans may have to worry about raptor predators and they also actively pursue their prey, so their senses seem to be much more sensitive.

These new  the findings challenge the assumption that snakes can't hear sound, such as humans talking or yelling, and could reshape the view on how they react to sound.

 PLoS ONE (2023). DOI: 10.1371/journal.pone.pone.0281285

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