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Comment by Dr. Krishna Kumari Challa on November 2, 2023 at 11:44am

Scientists Just Discovered a New Human Sense of Touch

A new study reveals a previously undiscovered way that we can feel light touches: directly through our hair follicles. Before now, it was thought that only nerve endings in the skin and around the hair follicles could transmit the sensation.

Researchers used an RNA sequencing process to find that cells in part of the hair follicle called the outer root sheath (ORS) had a higher percentage of touch-sensitive receptors than equivalent cells in the skin.

From there, the researchers produced lab cultures of human hair follicle cells together with sensory nerves.

When the hair follicle cells were mechanically stimulated, the sensory nerves next to them were also activated – showing that touch had been registered.

The experiments also revealed that the neurotransmitters serotonin and histamine were being released by the ORS cells through tiny sacs called vesicles, as a way of signaling to the surrounding cells.

Touch-sensing nerve cells are known as mechanoreceptors. They're the reason we can feel everything from a light breeze to a firm press. In this case, the hair follicle cells were interacting specifically with low-threshold mechanoreceptors (LTMRs), capable of feeling gentle touches.

https://www.science.org/doi/10.1126/sciadv.adh3273

Comment by Dr. Krishna Kumari Challa on November 2, 2023 at 11:36am

How Could a Piece of the Moon Become a Near-Earth Asteroid? Researchers Have an Answer

A team of astronomers has found a new clue that a recently discovered near-Earth asteroid, Kamo`oalewa, might be a chunk of the moon. They hypothesized that the asteroid was ejected from the lunar surface during a meteorite strike–and they found that a rare pathway could have allowed Kamo`oalewa to get into orbit around the sun while remaining close to the orbits of the Earth and the Moon.

Comment by Dr. Krishna Kumari Challa on November 2, 2023 at 10:14am

In a fascinating paper authored by Toth and posted to the arXiv preprint server, he explores the possibility that multiple gravitational lenses might provide extra amplification of light to provide a communication bridge between distant civilizations.

In a conventional gravitational lens, a large mass—such as a cluster of galaxies—sits between a more distant object and the Earth. As the light travels from the distant object, it is bent around the galaxy cluster, providing a lensing effect to astronomers on Earth, allowing them to a) study the distribution of matter in the lensing cluster but also to observe the more distant object a little more easily. Toth proposes that, just like a conventional telescope that uses multiple lenses, a multiple gravitational lens could provide even more amplification than a single system.

Toth explores combinations of multiple gravitational lenses using a variety of methods but focuses (sorry) attention on a two-lens system (so-called gravitational lens bridge), which is aligned along the central axis of the system, but found no advantages and no additional signal amplification over the results from a single lens system. In addition, photon mapping techniques were applied with the same outcome; a double-lens system offers no advantage over a single-lens system.

Applying the wave theory of light to the same two-lens system revealed the same results, but using computer graphics to perform ray tracing (which cannot be used to estimate amplification) can help to highlight visual features other techniques would be unable to produce. Using this approach, it suggested a two-lens system would produce two concentric Einstein rings; however, they would be very difficult to detect in real-world scenarios. In summary, then, a fascinating concept, especially the possibility of using a lens bridge for communication with distant civilizations, but the results are less than promising. Yes, there may well be double gravitational lenses, but as this paper shows, it is unlikely we will be able to detect them for now and sadly I suspect the idea of using them as a long-distance cosmic telephone will for now remain science fiction.

 Viktor T. Toth, Non-coplanar gravitational lenses and the "communication bridge", arXiv (2023). DOI: 10.48550/arxiv.2310.15957

Part 2

Comment by Dr. Krishna Kumari Challa on November 2, 2023 at 10:10am

Double gravitational lenses?!

How cool is it that the very universe we are trying to explore is actually providing us with telescopes to probe the darkest corners of space and time?

The alignment of large clusters of galaxies is the usual culprit whose gravity bends distant light to give us nature's own telescopes, but now our own Quora  physicist Viktor T Toth poses the question, "Can there be multiple gravitational lenses lined up and can they provide a 'communication bridge' to allow civilizations to communicate?"

 Albert Einstein in his general theory of relativity,  describes how the presence of matter can distort space around them. The famous analogy of placing a bowling ball at the center of a large rubber sheet causes a dip centered around the mass of the bowling ball. Any object rolling past the ball would find itself traveling through "curved space" and, therefore, find its path to be altered. This very concept is used successfully by space mission planners to adjust the trajectory of spacecraft exploring the solar system.

The same concept applies to light as it passes by massive objects like galaxy clusters and is the principle behind the gravitational lense. The first evidence of light being deflected by a massive object was performed in 1919 by Arthur Eddington and Frank Watson Dyson during a total solar eclipse. Gravitational lenses entered the scene 60 years later when they were first observed in 1979 by Dennis Walsh, Bob Carswell, and Ray Weymann using the 2.1m telescope at the Kitt Peak National Observatory.

Part 1

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

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