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Comment by Dr. Krishna Kumari Challa on September 22, 2021 at 12:43pm

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.

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Comment by Dr. Krishna Kumari Challa on September 22, 2021 at 10:11am

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...

Comment by Dr. Krishna Kumari Challa on September 22, 2021 at 10:04am

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...

Comment by Dr. Krishna Kumari Challa on September 21, 2021 at 6:10am

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...

Comment by Dr. Krishna Kumari Challa on September 21, 2021 at 6:05am

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...

Comment by Dr. Krishna Kumari Challa on September 21, 2021 at 5:39am

Science of Concrete & the Surfside Condo Collapse

Comment by Dr. Krishna Kumari Challa on September 21, 2021 at 5:35am

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...

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Comment by Dr. Krishna Kumari Challa on September 21, 2021 at 5:27am

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...

Comment by Dr. Krishna Kumari Challa on September 21, 2021 at 5:16am

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...

Comment by Dr. Krishna Kumari Challa on September 20, 2021 at 12:48pm

The Future of Wearable Tech

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