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Comment by Dr. Krishna Kumari Challa on November 2, 2023 at 9:48am

Human emissions have increased mercury in the atmosphere sevenfold: Study

Humans have increased the concentration of potentially toxic mercury in the atmosphere sevenfold since the beginning of the modern era around 1500 C.E., according to new research .

Researchers developed a new method to accurately estimate how much mercury is emitted annually from volcanos, the largest single natural emitter of mercury. The team used that estimate—along with a computer model—to reconstruct pre-anthropogenic atmospheric mercury levels. The researchers estimated that before humans started pumping mercury into the atmosphere, it contained on average about 580 megagrams of mercury. However, in 2015, independent research that looked at all available atmospheric measurements estimated the atmospheric mercury reservoir was about 4,000 Mg—nearly 7 times larger than the natural condition estimated in this study. Human emissions of mercury from coal-fired power plants, waste-incineration, industry and mining make up the difference. 

Methylmercury is a potent neurotoxicant that bioaccumulates in fish and other organisms—including us.

 Benjamin M. Geyman et al, Impacts of Volcanic Emissions on the Global Biogeochemical Mercury Cycle: Insights From Satellite Observations and Chemical Transport Modeling, Geophysical Research Letters (2023). DOI: 10.1029/2023GL104667

Comment by Dr. Krishna Kumari Challa on November 2, 2023 at 9:21am

New insights into the India–Asia collision in the Western Himalayas dating back to circa 55 million years

New Sangdanlin Section Data Suggests a Large Greater India

Comment by Dr. Krishna Kumari Challa on November 2, 2023 at 8:50am

Star fishes are just heads!

For centuries, naturalists have puzzled over what might constitute the head of a sea star, commonly called a "starfish." When looking at a worm, or a fish, it's clear which end is the head and which is the tail. But with their five identical arms—any of which can take the lead in propelling sea stars across the seabed—it's been anybody's guess how to determine the front end of the organism from the back. This unusual body plan has led many to conclude that sea stars perhaps don't have a head at all.

Researchers now have published a study finding that the truth is closer to the absolute reverse. In short, while the team detected gene signatures associated with head development just about everywhere in juvenile sea stars, expression of genes that code for an animal's torso and tail sections were largely missing.

Researchers used a variety of high-tech molecular and genomic techniques to understand where different genes were expressed during the development and growth of sea stars. A team  used micro-CT scanning to understand the shape and structure of the animal in unprecedented detail.

In another surprising finding, molecular signatures typically associated with the front-most portion of the head were localized to the middle of each of the sea star's arms, with these signatures becoming progressively more posterior moving out towards the arms' edges.

The research, published Nov. 1 in Nature, suggests that, far from being headless, over evolutionary time sea stars lost their bodies to become only heads.

It's as if the sea star is completely missing a trunk, and is best described as just a head crawling along the seafloor.

Almost all animals, including humans, are bilaterally symmetrical, meaning they can be split into two mirrored halves along a single axis extending from their head to their tail.

But the body plan of sea stars has long confounded scientists' understanding of animal evolution. Instead of displaying bilateral symmetry, adult sea stars—and related echinoderms, such as sea urchins and sea cucumbers—have a five-fold axis of symmetry without a clear head or tail.

 Laurent Formery, Molecular evidence of anteroposterior patterning in adult echinoderms, Nature (2023). DOI: 10.1038/s41586-023-06669-2. www.nature.com/articles/s41586-023-06669-2

Comment by Dr. Krishna Kumari Challa on November 1, 2023 at 12:14pm

Study directly links high insulin levels to pancreatic cancer

A new study from researchers reveals a direct link between high insulin levels, common among patients with obesity and type 2 diabetes, and pancreatic cancer.

The study, published in Cell Metabolism, provides the first detailed explanation of why people with obesity and type 2 diabetes are at an increased risk of pancreatic cancer. The research demonstrates that excessive insulin levels overstimulate pancreatic acinar cells, which produce digestive juices. This overstimulation leads to inflammation that converts these cells into precancerous cells.

While obesity and type 2 diabetes had previously been established as risk factors for pancreatic cancer, the exact mechanisms by which this occurred remained unclear. This new study sheds light on the role of insulin and its receptors in this process.

Hyperinsulinemia acts via acinar insulin receptors to initiate pancreatic cancer by increasing digestive enzyme production and inflammation, Cell Metabolism (2023). DOI: 10.1016/j.cmet.2023.10.003. www.cell.com/cell-metabolism/f … 1550-4131(23)00372-8

Comment by Dr. Krishna Kumari Challa on November 1, 2023 at 11:55am

How sunflowers 'see' the sun: Study describes a novel mechanism

Sunflowers famously turn their faces to follow the sun as it crosses the sky. But how do sunflowers "see" the sun to follow it? New work from plant biologists published Oct. 31 in PLOS Biology, shows that they use a different, novel mechanism from that previously thought.

Most plants show phototropism—the ability to grow toward a light source. Plant scientists had assumed that sunflowers' heliotropism, the ability to follow the sun, would be based on the same basic mechanism, which is governed by molecule called phototropin and responds to light at the blue end of the spectrum.

Sunflowers swing their heads by growing a little more on the east side of the stem—pushing the head west—during the day and a little more on the west side at night, so the head swings back toward the east. 

Researchers have  previously shown how sunflowers use their internal circadian clock to anticipate the sunrise, and to coordinate the opening of florets with the appearance of pollinating insects in the morning.

Indoors, sunflowers grew straight toward the light, activating genes associated with phototropin. But the plants grown outdoors, swinging their heads with the sun, showed a completely different pattern of gene expression. There was no apparent difference in phototropin between one side of the stem and another.

The researchers have not yet identified the genes involved in heliotropism.

Blocking blue, ultraviolet, red or far-red light with shade boxes had no effect on the heliotropism response. This shows that there are likely multiple pathways, responding to different wavelengths of light, to achieve the same goal.

Sunflowers are quick learners. When plants grown in the lab were moved outdoors, they started tracking the sun on the first day. That behaviour was accompanied by a burst of gene expression on the shaded side of the plant that did not recur on subsequent days. That suggests some kind of "rewiring" is going on.

 Apart from revealing previously unknown pathways for light-sensing and growth in plants, the discovery has broad relevance. Things that you define in a controlled environment like a growth chamber may not work out in the real world.

Multiple light signaling pathways control solar tracking in sunflowers, PLoS Biology (2023). DOI: 10.1371/journal.pbio.3002344. journals.plos.org/plosbiology/ … journal.pbio.3002344

Comment by Dr. Krishna Kumari Challa on November 1, 2023 at 11:35am

Antibiotics for common childhood infections no longer effective in many parts of the world

A new study has found that drugs to treat common infections in children and babies are no longer effective in large parts of the world, due to high rates of antibiotic resistance.

The  study found many antibiotics recommended by the World Health Organization (WHO) had less than 50% effectiveness in treating childhood infections such as pneumonia, sepsis (bloodstream infections) and meningitis. The findings show global guidelines on antibiotic use are outdated and need updates.

The most seriously affected regions are in Southeast Asia and the Pacific, including neighboring Indonesia and the Philippines, where thousands of unnecessary deaths in children resulting from antibiotic resistance occur each year.

The WHO has declared that antimicrobial resistance (AMR) is one of the top 10 global public health threats facing humanity. In newborns, an estimated three million cases of sepsis occur globally each year, with up to 570,000 deaths. Many of these are due to lack of effective antibiotics to treat resistant bacteria.

The findings, published in The Lancet regional Health—Southeast Asia, add to mounting evidence that common bacteria responsible for sepsis and meningitis in children are often resistant to prescribed antibiotics.

The research reveals the urgent need for global antibiotic guidelines to be updated, to reflect the rapidly evolving rates of AMR. 

The study found that one antibiotic in particular, ceftriaxone, was likely to be effective in treating only one in three cases of sepsis or meningitis in newborn babies.  Another antibiotic, gentamicin, was found likely to be effective in treating fewer than half of all sepsis and meningitis cases in children.

Gentamicin is commonly prescribed alongside aminopenicillins, which the study showed also has low effectiveness in combating bloodstream infections in babies and children.

AMR is more problematic for children than adults, as new antibiotics are less likely to be trialed on and made available to children.

The study analyzed 6,648 bacterial isolates from 11 countries across 86 publications to review antibiotic susceptibility for common bacteria causing childhood infections.

 Coverage gaps in empiric antibiotic regimens used to treat serious bacterial infections in neonates and children in Southeast Asia and the Pacific, The Lancet Regional Health—Southeast Asia (2023). DOI: 10.1016/j.lansea.2023.100291

Comment by Dr. Krishna Kumari Challa on November 1, 2023 at 10:02am

Humans are disrupting natural 'salt cycle' on a global scale

The planet's demand for salt comes at a cost to the environment and human health, according to a new scientific review . It  revealed that human activities are making Earth's air, soil and freshwater saltier, which could pose an "existential threat" if current trends continue.

Geologic and hydrologic processes bring salts to Earth's surface over time, but human activities such as mining and land development are rapidly accelerating the natural "salt cycle." Agriculture, construction, water and road treatment, and other industrial activities can also intensify salinization, which harms biodiversity and makes drinking water unsafe in extreme cases.

When you accumulate so much salt it could affect the functioning of vital parts or ecosystems.

When people think of salt, they tend to think of sodium chloride, but this work over the years has shown that human beings have disturbed other types of salts, including ones related to limestone, gypsum and calcium sulfate. 

When dislodged in higher doses, these ions can cause environmental problems.

Salt has even infiltrated the air. In some regions, lakes are drying up and sending plumes of saline dust into the atmosphere. In areas that experience snow, road salts can become aerosolized, creating sodium and chloride particulate matter.

Salinization is also associated with "cascading" effects. For example, saline dust can accelerate the melting of snow and harm communities.

 Because of their structure, salt ions can bind to contaminants in soils and sediments, forming "chemical cocktails" that circulate in the environment and have detrimental effects.

The anthropogenic salt cycle, Nature Reviews Earth & Environment (2023). DOI: 10.1038/s43017-023-00485-y

Comment by Dr. Krishna Kumari Challa on November 1, 2023 at 9:38am

Mining asteroids: A new method to extract metals from asteroids

Extraterrestrial mining and metal processing are key strategies for space exploration. In a new study in Scientific Reports,  a team of scientists in materials science, conducted catalytic dissolution of metals from meteorite proxies of metal-rich asteroids by using a deep eutectic solvent. These solvents are important for extraterrestrial mining since they can be designed to have relatively low vapor pressures and can comprise organic waste products from extraterrestrial settlements.

The team studied three types of meteorites, two chondrites, and one iron meteorite. The chondrite samples contained silicates with metal-rich phases such as native alloys, sulfides, and oxides, of which, the metallic iron-nickel and troilite formed the most abundant metal-bearing phases in all three samples, with specific hues in the iron-rich meteorite. The scientists subjected the samples to chemical micro-etching experiments with iodine and iron (III) chloride as oxidizing agents in a deep eutectic solvent formed by mixing choline chloride and ethylene glycol.

It is possible to establish viable extraterrestrial metal extractions, and the efficient use of local materials and resource recovery from space can significantly reduce the mass, cost, and environmental constraints of space missions. These large metal-rich asteroids are parental bodies of iron meteorites and metal-rich carbonaceous chondrites.  These metals can provide a local source of materials to establish a human settlement in space or other terrestrial bodies. Near Earth asteroids contain valuable platinum group metals and iron, nickel, and cobalt greater than that found on the Earth's surface.

The use of asteroids as mineral and metal resources provide a key step during space exploration with further investigations required for viable economic activity. The proposed technology is at a nascent stage and is very promising for metal recovery.

Rodolfo Marin Rivera et al, A novel method for extracting metals from asteroids using non-aqueous deep eutectic solvents, Scientific Reports (2023). DOI: 10.1038/s41598-023-44152-0

Comment by Dr. Krishna Kumari Challa on November 1, 2023 at 9:25am

Can female fertility survive harsh cancer therapy? Scientists who turned to animal models say the answer is 'yes'

Cancer treatment can rob childbearing-age women of fertility, but new research has uncloaked how the body's own traitor protein conspires with chemo and other harsh therapies against the ovaries' primordial follicles, home of immature oocytes—the entire ovarian egg reserve.

A fertility-damaging protein called CHEK2, when triggered by chemo's destruction of DNA, is singlehandedly to blame for coordinating deletion of primordial follicles containing immature eggs—oocytes—according to a research group. 

 But in a stunning discovery, albeit in mouse models conducted as part of the research, the team found that blocking CHEK2 with an inhibitor stops the protein's follicle-destroying activity, preserving the vital ovarian egg reserve and fertility. CHEK2 is an attractive target for future fertility-preserving interventions that ensure reproductive health and the likelihood of a successful pregnancy for women cancer survivors. When CHEK2 is deficient, these scientists say, oocytes can survive chemotherapy.

 Chihiro Emori et al, CHEK2 signaling is the key regulator of oocyte survival after chemotherapy, Science Advances (2023). DOI: 10.1126/sciadv.adg0898

Comment by Dr. Krishna Kumari Challa on October 31, 2023 at 1:48pm

The rotation of a black hole also isn't defined by the spin of physical mass, but rather by the twisting of spacetime around the black hole. When objects such as the Earth spin, they twist space around themselves very slightly. It's an effect known as frame dragging.

The spin of a black hole is defined by this frame-dragging effect. Black holes spin without the physical rotation of matter, just a twisted spacetime structure. This means there is an upper limit to this spin due to the inherent properties of space and time.

In Einstein's equations of general relativity, the spin of a black hole is measured by a quantity known as a, where a has to be between zero and one. If a black hole has no spin, then a = 0, and if it is at its maximal rotation, then a = 1.

This brings us to a new study on the rotation of the supermassive black hole in our galaxy. The team looked at radio and X-ray observations of the black hole to estimate its spin.

Due to the frame-dragging of spacetime near the black hole, the spectra of light from material near it is distorted. By observing the intensity of light at various wavelengths, the team was able to estimate the amount of spin.

What they found was that the a value for our black hole is between 0.84 and 0.96, which means it's rotating incredibly fast. At the upper range of the estimated rotation, it would be rotating at nearly the maximal rate.

This is even higher than the spin parameter of the black hole in M87, where a is estimated to be between 0.89 and 0.91.

Daly, Ruth A., et al. “New Black Hole Spin Values for Sagittarius A* Obtained with the Out....” Monthly Notices of the Royal Astronomical Society (2023): stad3228.

Part 2

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