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Comment by Dr. Krishna Kumari Challa on December 12, 2020 at 10:24am

How epigenetic switches control gene expression

Scientists at Tokyo Institute of Technology have deciphered how to quantitatively assess the effects of specific epigenetic changes on the rate of transcription by developing a mathematical model. Using their method, they successfully generated reconstituted chromatin-bearing histone modifications in vitro. Their study published in Nucleic Acids Research provides an accurate quantitative approach for understanding how site-specific changes to histone proteins impact the accessibility of chromatin and gene expression levels.

Masatoshi Wakamori et al, Quantification of the effect of site-specific histone acetylation on chromatin transcription rate, Nucleic Acids Research (2020). DOI: 10.1093/nar/gkaa1050

https://phys.org/news/2020-12-epigenetic-gene.html?utm_source=nwlet...

Comment by Dr. Krishna Kumari Challa on December 12, 2020 at 10:21am

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Black holes gain new powers when they spin fast enough

General relativity is a profoundly complex mathematical theory, but its description of black holes is amazingly simple. A stable black hole can be described by just three properties: its mass, its electric charge and its rotation or spin. Since black holes aren't likely to have much charge, it really takes just two properties. If you know a black hole's mass and spin, you know all there is to know about the black hole.

This property is often summarized as the no-hair theorem. Specifically, the theorem asserts that once matter falls into a black hole, the only characteristic that remains is mass. You could make a black hole out of a sun's worth of hydrogen, chairs or those old copies of National Geographic from Grandma's attic, and there would be no difference. Mass is mass as far as general relativity is concerned. In every case, the event horizon of a black hole is perfectly smooth, with no extra features. "The balck holes have no hair."

But with all its predictive power, general relativity has a problem with quantum theory. This is particularly true with black holes. If the no-hair theorem is correct, the information within an object is destroyed when it crosses the event horizon. Quantum theory says that information can never be destroyed. So the valid theory of gravity is contradicted by the valid theory of the quanta. This leads to problems such as the firewall paradox, which can't decide whether an event horizon should be hot or cold.

Several theories have been proposed to solve this contradiction, often involving extensions to relativity. The difference between standard relativity and these modified theories can only be seen in extreme situations, making them difficult to study observationally. But a new paper in Physical Review Letters shows how they might be studied through the spin of a black hole.

Many modified relativity theories have an extra parameter not seen in the standard theory. Known as a massless scalar field, it allows Einstein's model to connect with quantum theory  in a way that isn't contradictory. In this new work, the team looked at how such a scalar field connects to the rotation of a black hole. They found that at low spins, a modified black hole is indistinguishable from the standard model, but at high rotations, the scalar field allows a black hole to have extra features. In other words, in these alternative models, rapidly rotating black holes can have hair.

The hairy aspects of rotating black holes would only be seen near the event horizon itself, but they would also affect merging black holes. As the authors point out, future gravitational wave observatories should be able to use rapidly rotating black holes to determine whether an alternative to general relativity is valid.

Einstein's theory of general relativity has passed every observational challenge so far, but it will likely break down in the most extreme environments of the universe. Studies such as this show how we might be able to discover the theory that comes next.

 Alexandru Dima et al. Spin-Induced Black Hole Spontaneous Scalarization, Physical Review Letters (2020). DOI: 10.1103/PhysRevLett.125.231101

https://phys.org/news/2020-12-black-holes-gain-powers-fast.html?utm...

Comment by Dr. Krishna Kumari Challa on December 12, 2020 at 10:06am

Some droughts during the Indian monsoon are due to unique North Atl...

A team of researchers from the Indian Institute of Science and Cotton University has found that some droughts during monsoon season in India are due to unique North Atlantic disturbances. In their paper published in the journal Science, the group describes their study of weather patterns in South Asia over the past century and what it showed about monsoon season droughts.

P. J. Borah et al. Indian monsoon derailed by a North Atlantic wavetrain, Science (2020). DOI: 10.1126/science.aay6043

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Current pace of action on climate change is "unthinkable" state ex ...

Justifiable pride can be taken in the incremental accomplishments of international climate change cooperation, but it is "unthinkable" to continue at the current pace. The global response to climate change is completely insufficient and leaves the world on a "road to hell".

Climate Policy (2020). DOI: 10.1080/14693062.2020.1860567

Comment by Dr. Krishna Kumari Challa on December 12, 2020 at 10:01am

Scientists build whole functioning thymus from human cells

Researchers at the Francis Crick Institute and University College London have rebuilt a human thymus, an essential organ in the immune system, using human stem cells and a bioengineered scaffold. Their work is an important step towards being able to build artificial thymi which could be used as transplants.

The thymus is an organ in the chest where T lymphocytes, which play a vital role in the immune system, mature. If the thymus does not work properly or does not form during foetal development in the womb, this can lead to diseases such as severe immunodeficiency, where the body cannot fight infectious diseases or cancerous cells, or autoimmunity, where the immune system mistakenly attacks the patient's own healthy tissue.

In their proof-of-concept study, published in Nature Communications today, the scientists rebuilt thymi using stem cells taken from patients who had to have the organ removed during surgery. When transplanted into mice, the bioengineered thymi were able to support the development of mature and functional human T lymphocytes.

While researchers have previously rebuilt other organs or sections of organs, this is the first-time scientists have successfully rebuilt a whole working human thymus. 

Campinoti, S et al. (2020). Reconstitution of a functional human thymus by postnatal stromal progenitor cells and natural whole-organ scaffolds. Nature Communications, DOI: 10.1038/s41467-020-20082-7

https://medicalxpress.com/news/2020-12-scientists-functioning-thymu...

Comment by Dr. Krishna Kumari Challa on December 12, 2020 at 9:21am

Since its completion in November 1963, the Telescope had been used for radar astronomy and radio astronomy, and had been part of the Search for extraterrestrial intelligence (SETI) program. It was also used by NASA for Near-Earth object detection.
Arecibo joins with telescopes in Europe and with the Russian Radio Astron satellite to form the largest telescope ever – 20 times the size of the Earth. Arecibo continues to obtain orbit refinement of potentially hazardous near-Earth asteroids (PHAs) to identify possible future Earth impactors.
It has several acheivements since it started working
http://www.naic.edu/about/accomplishments.html#:~:text=Arecibo%20jo....

Comment by Dr. Krishna Kumari Challa on December 11, 2020 at 9:49am

Distinct Microbiome and Metabolites Linked with Depression

The gastrointestinal tracts of people with major depressive disorder harbor a signature composition of viruses, bacteria, and their metabolic products, according to the most comprehensive genomic and metabolomic analysis in depression to date.

A study published December 2 in Science Advances changes all that with its vivid description of a distinct microbiome associated with major depressive disorder, as well as the profile of molecules these organisms produce. The researchers were able to use this microbial “fingerprint” to distinguish between individuals with MDD and healthy controls, solely on the composition of a few microbes and compounds in their fecal matter.

J. Yang et al., “Landscapes of bacterial and metabolic signatures and their interaction in major depressive disorders,” Science Advances, 6:eaba8555, 2020.

Comment by Dr. Krishna Kumari Challa on December 11, 2020 at 9:24am

How kids’ immune systems evade COVID A growing body of evidence suggests why young children account for only a small percentage of COVID-19 infections: their immune systems seem better equipped to eliminate SARS-CoV-2 t.... Some children who do get infected never test positive for the virus on a standard RNA test, even if they develop symptoms and have antibodies specific to SARS-CoV-2. Their immune system sees the virus “and it just mounts this really quick and effective immune response that shuts it down, before it has a chance to replicate to the point that it comes up positive on the swab diagnostic test”, says immunologist Melanie Neeland. The source of children’s immune advantage is thought to arise from one — or several — of these factors: Children’s T cells are untrained, so they might have a greater capacity to respond to new viruses. Children might have a strong innate immune response from birth, although that raises the question of why it isn’t seen with other viruses that can cause severe disease in children. It could be thanks to the protection of antibodies to seasonal common-cold coronaviruses, which run rampant in children. Kids might receive a smaller dose when exposed to SARS-CoV-2, because their noses contain fewer of the ACE2 receptors that the virus uses to gain access.

Comment by Dr. Krishna Kumari Challa on December 11, 2020 at 8:23am

** The greening of the Earth is approaching its limit

When plants absorb this gas to grow, they remove it from the atmosphere and it is sequestered in their branches, trunk or roots. An article published today in Science shows that this fertilizing effect of CO2 is decreasing worldwide, according to the text co-directed by Professor Josep Peñuelas of the CSIC at CREAF and Professor Yongguan Zhang of the University of Nanjin, with the participation of CREAF researchers Jordi Sardans and Marcos Fernández. The study, carried out by an international team, concludes that the reduction has reached 50% progressively since 1982 due basically to two key factors: the availability of water and nutrients.

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COVID-19 and other pandemics are the effects of our negative impact...

There is increasing awareness that the COVID-19 pandemic is the consequence of environmental and societal crises. A new paper just published in the scientific journal Science of the Total Environment by international research fellows of the Konrad Lorenz Institute for Evolution and Cognition Research (KLI), an Austrian independent center for advanced studies in the life and sustainability sciences, presents an interdisciplinary approach to analyze the COVID-19 pandemic as a phenomenon affecting the diversity of all spheres of the total environment.

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Bad news for fake news: New research helps combat social media misi...

Rice University researchers have discovered a more efficient way for social media companies to keep misinformation from spreading online using probabilistic filters trained with artificial intelligence.

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Researchers shed new light on mysteries behind the light emission o...

A team of researchers from the NYU Abu Dhabi's (NYUAD) Smart Materials Lab (SML) led by Professor of Chemistry Panče Naumov has conducted a thorough review of the scientific literature surrounding the natural production of light, called bioluminescence, and developed conclusions that will help others in the field direct their research to uncover the mysteries behind this fascinating natural phenomenon.

Comment by Dr. Krishna Kumari Challa on December 11, 2020 at 8:19am

Researchers identify the physical mechanism that can kill bacteria with gold nanoparticles

Finding alternatives to antibiotics is one of the biggest challenges facing the research community. Bacteria are increasingly resistant to these drugs, and this resistance leads to the deaths of more than 25,000 around the world. Now, a multidisciplinary team of researchers have discovered that the mechanical deformation of bacteria is a toxic mechanism that can kill bacteria with gold nanoparticles. The results of this research have been published in the journal Advanced Materials and are a breakthrough in researchers' understanding the antibacterial effects of nanoparticles and their efforts to find new materials with bactericide properties.

Since the times of Ancient Egypt, gold has been used in a range of medical applications and, more recently, as for diagnosing and treating diseases such as cancer. This is due to the fact that gold is a chemically inert material, that is, it does not react or change when it comes into contact with an organism. Amongst the scientific community, nanoparticles are known for their ability to make tumors visible and for their applications in nanomedicine.

This new research shows that these chemically inert nanoparticles can kill bacteria thanks to a physical mechanism that deforms the cell wall. To demonstrate this, the researchers have synthesized in the laboratory gold nanoparticles in the shape of an almost perfect sphere and others in the shape of stars, all measuring 100 nanometres (8 times thinner than a hair). The group analyzed how these particle interact with living bacteria. Researchers found that the bacteria become deformed and deflate like a ball that is having the air let out before dying in the presence of these nanoparticles as if the cell wall had spontaneously exploded. 

The scientists thought that a physical mechanism might be responsible for the death of the bacteria. Consequently, they carried out aa numerical simulations to analyze how a homogenous layer of individual nanoparticles could apply sufficient mechanical tension to the cell wall of the bacteria that it ends up breaking seemingly by stretching, like a balloon that is inflated from different points until it exploded.

To confirm this hypothesis, the researchers created an artificial model of a bacterial cell membrane to evaluate its response when it entered into contact with the 100 nm gold nanoparticles. They found that the model spontaneously contracted until it completely collapsed, thus proving the hypothesis that nanoparticles apply a mechanical stretch on the cell membrane of the bacteria.

Denver P. Linklater et al, Antibacterial Action of Nanoparticles by Lethal Stretching of Bacterial Cell Membranes, Advanced Materials (2020). DOI: 10.1002/adma.202005679

https://phys.org/news/2020-12-physical-mechanism-bacteria-gold-nano...

Comment by Dr. Krishna Kumari Challa on December 11, 2020 at 7:14am

Blocking protein restores strength, endurance in old mice, study finds

Muscle loss during aging is known as sarcopenia, and it accounts for billions of dollars of health care expenditures  each year as people lose the ability to care for themselves, experience more falls and become increasingly less mobile. It is due to changes in muscle structure and function: The muscle fibers shrink and the number and function of the cellular powerhouses known as mitochondria dwindle.

Blocking the activity of a single protein in old mice for one month restores mass and strength to the animals' withered muscles and helps them run longer on a treadmill, according to a study by researchers. Conversely, increasing the expression of the protein in young mice causes their muscles to atrophy and weaken.

The improvement is really quite dramatic. The old mice are about 15% to 20% stronger after one month of treatment, and their muscle fibres look like young muscle. Considering that humans lose about 10% of muscle strength per decade after about age 50, this is quite remarkable.

The protein hasn't previously been implicated in aging. The researchers show that the amount of the protein, called 15-PGDH, is elevated in old muscle and is widely expressed in other old tissues. Experiments they conducted in human tissue raise hopes for a future treatment for the muscle weakness that occurs as people age.

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Prostaglandin E2 levels are regulated by 15-PGDH, which breaks down prostaglandin E2. The researchers used a highly sensitive version of mass spectrometry, a method for differentiating closely related molecules, to determine that compared with young mice, the 15-PGDH levels are elevated in the muscles of older animals, and the levels of prostaglandin E2 are lower.

They found a similar pattern of 15-PGDH expression in human muscle tissues, as those from people in their 70s and early 80s expressed higher levels than those from people in their mid-20s.

"We knew from our previous work that prostaglandin E2 was beneficial for regeneration of young muscles.

"Inhibition of prostaglandin-degrading enzyme 15-PGDH rejuvenates aged muscle mass and strength" Science (2020). science.sciencemag.org/lookup/ … 1126/science.abc8059

https://medicalxpress.com/news/2020-12-blocking-protein-strength-mi...

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