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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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Comment by Dr. Krishna Kumari Challa on October 31, 2023 at 1:46pm

Milky Way's Black Hole Is Spinning at Near Maximum

Pick any object in the Universe, and it is probably spinning. Asteroids tumble end over end, planets and moons rotate on their axes, and even black holes spin.

And for everything that spins, there is a maximum rate at which it can rotate. The black hole in our galaxy is spinning at nearly that maximum rate.

For objects such as the Earth, the maximum rate of rotation is defined by its surface gravity. The weight we feel while standing on the Earth isn't just due to the gravitational pull of the Earth.

Gravity pulls us toward the center of our world, but the Earth's rotation also tends to fling us outward away from the Earth. This "centrifugal" force is tiny, but it does mean that your weight at the equator is just slightly less than it is at the north or south pole.

With our 24-hour day, the weight difference between the equator and pole is just 0.3%. But Saturn's 10-hour day means that the difference is 19%. So much that Saturn bows outward a bit at its equator.

Now imagine a planet spinning so fast that the difference was 100%. At that point, the gravitational pull of the planet and its centrifugal force at the equator would cancel out.

If the world were to spin any faster, it would fly apart. It would likely fly apart at an even slower spin rate, but this is clearly the maximum rate of rotation.

For black holes, things are a bit different. Black holes aren't objects with a physical surface. They aren't made of material that could fly apart. But they still have a maximum rate of rotation.

Black holes are defined by their tremendous gravity, which distorts space and time around them. The event horizon of the black hole marks the point of no return for nearby objects, but it isn't a physical surface.

Part 1

Comment by Dr. Krishna Kumari Challa on October 31, 2023 at 1:20pm

Scientific Jargon - explained
'Climate Quitting':

Climate quitting means leaving your job due to concerns about your employer's impact on the climate or because you want to work directly on addressing climate issues.

Comment by Dr. Krishna Kumari Challa on October 31, 2023 at 1:03pm

Life on Earth under 'existential threat': climate scientists

Climate change poses an "existential threat" to life on Earth, prominent scientists warned recently, in an assessment on this year's avalanche of heat records and weather extremes that they said are hitting more ferociously than expected.

With expectations that 2023 will be the hottest year on record, regions across the planet have been scorched by deadly heat waves.

Others have been hit by floods, or in some cases, have suffered both extremes in quick succession.

"The truth is that we are shocked by the ferocity of the extreme weather events in 2023. We are afraid of the uncharted territory that we have now entered," said an international coalition of authors in a new report published in the journal BioScience.

Their stark assessment: "Life on planet Earth is under siege". They said humanity had made "minimal progress" in curbing its planet-heating emissions, with major greenhouse gases at record levels, and subsidies for fossil fuels soaring last year.

The study on the state of the climate looked at recent data on 35 planetary "vital signs" and found 20 of these were at record extremes this year.

William Ripple et al, 2023 State of the Climate Report: Entering Uncharted Territory, BioScience (2023). DOI: 10.1093/biosci/biad080

Comment by Dr. Krishna Kumari Challa on October 31, 2023 at 12:59pm

Asteroid dust caused 15-year winter that killed dinosaurs: Study

Around 66 million years ago, an asteroid bigger than Mount Everest smashed into Earth, killing off three quarters of all life on the planet—including the dinosaurs.

But exactly how the impact of the asteroid Chicxulub caused all those animals to go extinct has remained a matter of debate till now.

The leading theory recently has been that sulfur from the asteroid's impact—or soot from global wildfires it sparked—blocked out the sky and plunged the world into a long, dark winter, killing all but the lucky few.

However research published recently based on particles found at a key fossil site reasserted an earlier hypothesis: that the impact winter was caused by dust kicked up by the asteroid.

Fine silicate dust from pulverized rock would have stayed in the atmosphere for 15 years, dropping global temperatures by up to 15 degrees Celsius, researchers said in a study in the journal Nature Geoscience.

 Cem Berk Senel et al, Chicxulub impact winter sustained by fine silicate dust, Nature Geoscience (2023). DOI: 10.1038/s41561-023-01290-4

Comment by Dr. Krishna Kumari Challa on October 31, 2023 at 12:30pm

Scientists isolate 'pre-emerging' bat coronavirus but also identify existing medication that potently neutralizes it

Repeated outbreaks of bat-derived coronaviruses among humans and other mammals have heightened the need for a broad range of therapeutics—monoclonal antibodies and antivirals—treatments that can come immediately "off-the-shelf" to address newly-emerging zoonotic threats.

A groundbreaking series of experiments by scientists at collaborating research centers has not only identified a "pre-emerging bat coronavirus," but investigators have additionally demonstrated that an off-the-shelf monoclonal antibody neutralized it potently. Additionally, in vitro tests of widely-used antivirals were also effective against the virus, researchers found.

The bat-derived coronavirus is more specifically known as BtCoV-422. And a neutralizing monoclocal antibody developed to treat Middle East respiratory syndrome coronavirus—MERS-CoV—has been available for years and is known as mAb JC57-11. MERS-CoV is a bat-derived zoonotic virus that infects dromedary camels, the animals that transmit the virus to people. BtCoV-422 is genetically similar to MERS-CoV.

Writing in Science Translational Medicine, investigators  who underscored a deceptively simple principle: the types of countermeasures that have worked against other coronaviruses, such as MERS-CoV and SARS-CoV-2, should impact BtCoV-422. But while investigators found that most MERS-CoV–neutralizing monoclonal antibodies had very limited activity against the virus, mAb JC57-11 delivered a powerful one-two punch.

Longping V. Tse et al, A MERS-CoV antibody neutralizes a pre-emerging group 2c bat coronavirus, Science Translational Medicine (2023). DOI: 10.1126/scitranslmed.adg5567

Comment by Dr. Krishna Kumari Challa on October 30, 2023 at 10:00am

Volcanic eruptions found to dampen Indian Ocean El Niño events 

Volcanic eruptions occurring in tropical regions (23°N/S of the equator) have been linked to abrupt disruption of global-scale climate cycles in the Indian Ocean over the last 1 million years in new research published in Geophysical Research Letters. El Niño Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) are ocean-atmosphere climate interactions that were found to be disrupted for almost a decade before returning to pre-eruption baseline levels, and the effect increases with greater eruption intensity.

Benjamin H. Tiger et al, Tropical Volcanic Eruptions and Low Frequency Indo‐Pacific Variability Drive Extreme Indian Ocean Dipole Events, Geophysical Research Letters (2023). DOI: 10.1029/2023GL103991

Comment by Dr. Krishna Kumari Challa on October 30, 2023 at 9:52am

In previous work by scientists, these mutations have been shown to have an impact on diseases such as inflamatoy bowl disease. In this new study, researchers explored if the same was true for psoriasis.

Psoriasis is a chronic inflammatory immune-mediated disease that causes patches of skin to become flaky or sore. The current cause of the condition is unknown and it is estimated that 125 million people worldwide—2% to 3% of the total population—have psoriasis.

This team took skin samples from the forearms of 111 people with psoriasis, taking samples from psoriasis patches and healthy skin. They used laser capture microdissection to isolate 1,182 samples, which were then analyzed by whole genome or exome sequencing.

They found minimal differences in the types of mutations seen in healthy skin versus psoriasis patches and only a slight increase in the number of mutations. In addition to this, no functional differences were seen between psoriasis and non-psoriasis tissue, suggesting that the condition is not linked to a specific somatic mutation in the skin.

The team identified four new driver mutations that gave skin cells an advantage over their neighbors, all found in both psoriasis patches and other skin tissue. They also found a mutational signature linked with the use of psoralens, a compound sometimes used as part of a treatment for psoriasis flare-ups. However, these mutations were found in patients who had been prescribed psoralens along with those who hadn't, suggesting that it could have come from environmental exposure.

 Sigurgeir Olafsson et al, Effects of psoriasis and psoralen exposure on the somatic mutation landscape of the skin, Nature Genetics (2023). DOI: 10.1038/s41588-023-01545-1

Part 2

Comment by Dr. Krishna Kumari Challa on October 30, 2023 at 9:50am

Psoriasis not caused by spontaneous mutations : Study

Psoriasis—a chronic skin condition—is not caused or spread by spontaneous genetic mutations in the skin, new research suggests.

Researchers sequenced skin samples from 111 people with psoriasis. They didn't find any mutated genes in the psoriatic patches that weren't also mutated in the individual's unaffected skin tissue. The study, published in Nature Genetics, suggests that unlike other inflammatory diseases, such as inflammatory bowel disease or chronic liver disease, somatic mutations were not responsible for the start or spread of psoriasis.  

Confirming that psoriasis is not caused by any somatic mutations enables researchers to continue to explore other avenues.

Over time, all cells in our bodies will accumulate mutations, known as somatic mutations. These can arise from replication errors, chemicals, or environmental factors. While some of these mutations can lead to cancer, many are harmless. When a mutation gives the cell an advantage over its neighbors, it is known as a driver mutation, and this allows the mutated cells to grow and spread.

Recently, research has begun to explore the possibility of driver mutations causing non-cancerous diseases by impacting the function of the tissue or influencing the spread of disease through the body.

Part 1

Comment by Dr. Krishna Kumari Challa on October 30, 2023 at 9:41am

Nanoparticles found to be effective for the treatment of rheumatoid arthritis

A team of scientists has developed a new solution for the treatment of rheumatoid arthritis (RA).

RA is a chronic disease that, unfortunately, has no cure. The disease triggers a mix of troublesome symptoms like inflamed joints, harmful cytokines, and immune system imbalances, which work together to create a relentless cycle of worsening symptoms. While targeting some of these factors can provide short-term relief, others remain unresolved, leading to a frustrating cycle of remission and flare-ups.

One of the major hurdles in RA treatment is the inability to restore the immune system to its healthy state. This leaves the body unable to control the continuous production of harmful substances like reactive oxygen species (ROS) and inflammatory cytokines, leading to persistent inflammation and discomfort. In essence, the ideal treatment for RA should not only provide immediate relief from inflammation and symptoms but also address the root cause by restoring the immune system to its normal, balanced state.

The new work involves immobilizing ceria nanoparticles (Ce NPs) onto mesenchymal stem cell-derived nanovesicles (MSCNVs). Both of these components can hinder different pathogenic factors, allowing them to work both individually and cooperatively to achieve a comprehensive treatment.

Ce NPs can scavenge the overproduced ROS in RA-inflicted knee joints. They also induce polarization of M1 macrophages into M2, achieving immediate relief of inflammation and symptoms. MSCNVs deliver immunomodulatory cytokines, which turn dendritic cells (DC) into tolerogenic dendritic cells (tDCs). This consequently generates regulatory T cells for long-term immune tolerance. In short, this approach aims to bridge both innate and adaptive immunity to achieve both short-term pain relief, as well as convert the tissue environment into an immune-tolerant state to prevent the recurrence of symptoms.

Researchers confirmed the efficacy of this approach using a collagen-induced arthritis mouse model. The Ce-MSCNV system was able to comprehensively treat and prevent RA by simultaneously relieving the immediate and restoring T cell immunity. Supporting data suggest that improvement in conditions can be achieved after only a single-dose treatment.

The mice treated with the Ce-MSCNV combination fared far better compared to the ones only treated using the Ce NP or MSCNV group. This clearly demonstrates the synergy between anti-inflammation and immunomodulation and underlines the importance of the combined therapy for effective RA treatment. In addition, Ce-MSCNV administration prior to booster injection markedly reduced the incidence and severity of symptoms, supporting the prophylactic potential of these nanoparticles.

Koo Sagang et al, Ceria-vesicle nanohybrid therapeutic for modulation of innate and adaptive immunity in a collagen-induced arthritis model, Nature Nanotechnology (2023). DOI: 10.1038/s41565-023-01523-y

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