Comment

Comment by Dr. Krishna Kumari Challa on September 23, 2021 at 9:57am

Flying cars

Comment by Dr. Krishna Kumari Challa on September 23, 2021 at 9:51am

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...

**

Comment by Dr. Krishna Kumari Challa on September 23, 2021 at 9:44am

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...

Comment by Dr. Krishna Kumari Challa on September 22, 2021 at 1:26pm

Brain-Eating Amoeba

Comment by Dr. Krishna Kumari Challa on September 22, 2021 at 1:20pm

Salty Diet Helps Gut Bugs Fight Cancer in Mice: Study

A high-salt diet suppressed the growth of tumors in a mouse model of melanoma, apparently because of an interplay between the gut microbiome and natural killer cells.

Salt may not be good for your BP, but .....

In mice, a diet high in salt suppresses tumor growth—but only when gut microbes are there to stimulate immune cells, a September 10 study in Science Advances reports. The findings raise tantalizing questions about the role of diet and gut microbes in human cancers, and may point to new avenues for therapeutic development.

While the study isn’t the first to connect a high-salt diet to shrinking tumors, the authors have shown a unique mechanistic role of high salt induced gut microbiome changes as the central phenomenon behind their observed anti-cancer effect.

The researchers  pursued this line of inquiry because previous research had linked high salt intake with autoimmune diseases, suggesting that increased salt stimulates immune cells. Meanwhile, tumors are well known to grow in immune-suppressive environments. So they thought, “If we put salt in the mice’s diet, maybe [the immune system in] the tumor environment becomes activated,” suppressing cancerous growth.

a 2019 Frontiers in Immunology study from a European team led by Hasselt University immunologist Markus Kleinewietfeld reported that high-salt diets inhibited tumor growth in mice. No researchers carried out similar experiments, implanting mice with B16F10 skin melanoma cells and then feeding the tumor transplant mice diets with different salt levels, they got similar results: tumors grew slower in mice who were fed a high-salt diet.

https://www.science.org/doi/10.1126/sciadv.abg5016

https://www.the-scientist.com/news-opinion/a-salty-diet-helps-gut-b...

Comment by Dr. Krishna Kumari Challa on September 22, 2021 at 12:57pm

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...

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.

Part1

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...

• ‹ Previous
• 1
• …
• 625
• 626
• 627
• 628
• 629
• …
• 1135
• Next ›
• Page