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Comment by Dr. Krishna Kumari Challa on September 3, 2020 at 5:46am

 The widespread footprint of blue jean microfibers

Blue jeans are a more popular wardrobe choice undoubtdly. But most people don't think about microscopic remnants of their comfy jeans and other clothing that are shed during laundering. Now, researchers reporting in ACS' Environmental Science & Technology Letters have detected indigo denim microfibers not only in wastewater effluent, but also in lakes and remote Arctic marine sediments.

Samantha N. Athey et al. The Widespread Environmental Footprint of Indigo Denim Microfibers from Blue Jeans, Environmental Science & Technology Letters (2020). DOI: 10.1021/acs.estlett.0c00498

https://phys.org/news/2020-09-widespread-footprint-blue-jean-microf...

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  Viruses could be harder to kill after adapting to warm environments

Enteroviruses and other pathogenic viruses that make their way into surface waters can be inactivated by heat, sunshine and other microbes, thereby reducing their ability to spread disease. But researchers report now that global warming could cause viruses to evolve, rendering them less susceptible to these and other disinfectants, such as chlorine. They also say that this greater hardiness could increase the length of time heat-adapted viruses would be infectious enough to sicken someone who comes in contact with contaminated water.

Anna Carratalà et al. Adaptation of Human Enterovirus to Warm Environments Leads to Resistance against Chlorine Disinfection, Environmental Science & Technology (2020). DOI: 10.1021/acs.est.0c03199

https://phys.org/news/2020-09-viruses-harder-environments.html?utm_...

Comment by Dr. Krishna Kumari Challa on September 3, 2020 at 5:44am

Massive release of methane gas from the seafloor discovered for the first time in the Southern Hemisphere

Gas hydrate is an ice-like substance formed by water and methane at depths of several hundred meters at the bottom of our oceans at high pressure and low temperatures. Methane is a potent greenhouse gas, roughly 25 times more potent than carbon dioxide, and it is estimated that methane frozen in these sediments constitute the largest organic carbon reservoir on Earth. The fact that methane gas has now started leaking out through gas hydrate dissociation is not good news for the climate.

It has been estimated that there are more organic carbon in the form of methane in hydrates than in all fossil fuels combined. The leakage of methane could lead to a feedback loop in which the ocean warming melts gas hydrates resulting in the release of methane from the ocean floor into the water. The warmer it gets, the more methane leaks out.

This process is believed to have triggered and amplified climate changes in our geological past.

Marcelo Ketzer et al. Gas hydrate dissociation linked to contemporary ocean warming in the southern hemisphere, Nature Communications (2020). DOI: 10.1038/s41467-020-17289-z

https://phys.org/news/2020-09-massive-methane-gas-seafloor-southern...

Comment by Dr. Krishna Kumari Challa on September 3, 2020 at 5:37am

Revolutionary quantum breakthrough paves way for safer online communication

The world is one step closer to having a totally secure internet and an answer to the growing threat of cyber-attacks, thanks to a team of international scientists who have created a unique prototype which could transform how we communicate online.

S.K. Joshi el al., "A trusted node–free eight-user metropolitan quantum communication network," Science Advances (2020). advances.sciencemag.org/lookup … .1126/sciadv.aba0959

https://phys.org/news/2020-09-revolutionary-quantum-breakthrough-pa...

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Asphalt adds to air pollution, especially on hot, sunny days

Asphalt is a near-ubiquitous substance—it's found in roads, on roofs and in driveways—but its chemical emissions rarely figure into urban air quality management plans.

A new study finds that asphalt is a significant source of air pollutants in urban areas, especially on hot and sunny days.

Researchers observed that common road and roofing asphalts produced complex mixtures of organic compounds, including hazardous pollutants, in a range of typical temperature and solar conditions.

 P. Khare el al., "Asphalt-related emissions are a major missing nontraditional source of secondary organic aerosol precursors," Science Advances (2020). advances.sciencemag.org/lookup … .1126/sciadv.abb9785

https://phys.org/news/2020-09-asphalt-air-pollution-hot-sunny.html?...

Comment by Dr. Krishna Kumari Challa on September 3, 2020 at 5:30am

Oldest radiocarbon dated temperate hardwood tree in the world discovered

https://phys.org/news/2020-08-oldest-radiocarbon-dated-temperate-ha...

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How to remove unwanted components from the cell nucleus

The organization of cells into specific compartments is critical for their function. For instance, by separating the nucleus from the cytoplasm, the nuclear envelope prevents premature translation of immature RNAs.

During mitosis, however, thenuclear envelope disassembles, allowing large cytoplasmic components such as ribosomes to mix with nuclear material. When the nuclear envelope reassembles following mitosis, these cytoplasmic components must once again be removed. "The nuclear envelope can contribute to this by actively importing or exporting substrates up to a certain size, but it was not clear what happens with very large cytoplasmic components Until now.

A research team from has now shown that large components such as ribosomes are in fact removed from the forming nucleus before the nuclear envelope is assembled again. This exclusion process requires the protein Ki-67. In a older study it was discovered that Ki-67 was responsible for keeping chromosomes separated in early stages of mitosis by acting as a surfactant. Remarkably, it was now found that it changes its properties at the end of mitosis and performs the opposite function, namely clustering of chromosomes.

By coming together into a dense cluster at the end of cell division, chromosomes are able to exclude large cytoplasmic components before the nuclear envelope reforms.

This work shows how a single protein can dynamically change the surface properties of chromosomes.

Ultimately, this facilitates effective compartmentalisation of key processes within the cell.

Daniel Gerlich et al. Chromosome clustering by Ki-67 excludes cytoplasm during nuclear assembly. Nature, published on 02 September 2020. DOI: 10.1038/s41586-020-2672-3

https://phys.org/news/2020-08-unwanted-components-cell-nucleus.html...

Comment by Dr. Krishna Kumari Challa on September 3, 2020 at 5:25am

Researchers reprogram yeast cells to become microscopic drug factories

Since antiquity, cultures on nearly every continent have discovered that certain plant leaves, when chewed or brewed or rubbed on the body, could relieve diverse ailments, inspire hallucinations or, in higher dosages, even cause death. Today, pharmaceutical companies import these once-rare plants from specialized farms and extract their active chemical compounds to make drugs like scopolamine for relieving motion sickness and postoperative nausea, and atropine, to curb the drooling associated with Parkinson's disease or help maintain cardiac function when intubating COVID-19 patients and placing them on ventilators.

Now, Stanford engineers are recreating these ancient remedies in a thoroughly modern way by genetically reprogramming the cellular machinery of a special strain of yeast, effectively transforming them into microscopic factories that convert sugars and amino acids into these folkloric drugs, in much the same way that brewers' yeast can naturally convert sugars into alcohol.

Biosynthesis of medicinal tropane alkaloids in yeast, Nature (2020). DOI: 10.1038/s41586-020-2650-9 , www.nature.com/articles/s41586-020-2650-9

https://phys.org/news/2020-09-reprogram-yeast-cells-microscopic-dru...

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Has Earth's oxygen rusted the Moon for billions of years?

https://phys.org/news/2020-09-earth-oxygen-rusted-moon-billions.htm...

https://www.quora.com/q/sciencecommunication/Has-Earths-oxygen-rust...;   --check %%

Comment by Dr. Krishna Kumari Challa on September 3, 2020 at 5:17am

Study details how general anesthetics and 'benzos' act on receptors in the brain

As you drift into unconsciousness before a surgery, general anesthetic drugs flowing through your blood are putting you to sleep by binding mainly to a protein in the brain called the γ-aminobutyric acid type A (GABA_A) receptor. Now UT Southwestern scientists have shown exactly how anesthetics attach to the GABA_A receptor and alter its three-dimensional structure, and how the brain can tell the difference between anesthetics and the psychoactive drugs known as benzodiazepines—which also bind to the GABA_A receptor. The findings were published online today in the journal Nature.

The GABA_A receptor is an ion channel; when it's in an open conformation, it allows chloride ions to flow through. This movement of ions decreases the signaling of brain cells, calming brain activity. So stimulating the GABA_A receptor—as anesthetics, benzodiazepines, alcohol, anti-seizure, and some sleep medications all do—quiets the brain in a variety of ways.

The team discovered that both general anesthetics and diazepam could bind to multiple places on the GABA_A molecule. One site—dubbed the "benzo site" in earlier research—was unique to the diazepam. But another site overlapped between the two drug types. When diazepam was present at high enough doses, it bound to this site that was more often used by the anesthetics. This observation could explain why high doses of benzodiazepines like diazepam can have anesthetic-like effects. The researchers also found differences among the general anesthetics; phenobarbital, for instance, bound to a place on GABA_A that neither etomidate nor propofol attached, and seemed to be less choosy about where it bound.

Shared structural mechanisms of general anaesthetics and benzodiazepines, Nature (2020). DOI: 10.1038/s41586-020-2654-5 , www.nature.com/articles/s41586-020-2654-5

https://phys.org/news/2020-09-anesthetics-benzos-receptors-brain.ht...

Comment by Dr. Krishna Kumari Challa on September 3, 2020 at 5:06am

Heaviest black hole merger is among three recent gravitational wave discoveries

Scientists observed what appears to be a bulked-up black hole tangling with a more ordinary one. They detected two black holes merging, but one of the black holes was 1 1/2 times more massive than any ever observed in a black hole collision. The researchers believe the heavier black hole in the pair may be the result of a previous merger between two black holes.This type of hierarchical combining of black holes has been hypothesized in the past but the observed event, labeled GW190521, would be the first evidence for such activity. 

The scientists identified the merging black holes by detecting the gravitational waves—ripples in the fabric of space-time—produced in the final moments of the merger.

The larger black hole in the merging pair has a mass 85 times greater than the sun. One possible scenario suggested by the new papers is that the larger object may have been the result of a previous black hole merger rather than a single collapsing star. According to current understanding, stars that could give birth to black holes with masses between 65 and 135 times greater than the sun don't collapse when they die. Therefore, we don't expect them to form black holes.

All three events now observed, are novel with masses or mass ratios that we've never seen before

The research paper, "GW190521: A Binary Black Hole Coalescence with a Total Mass of 150 Solar Masses," was published in Physical Review Letters on September 2, 2020: DOI: 10.1103/PhysRevLett.125.101102

The research paper, "Properties and Astrophysical Implications of the 150 Solar Mass Binary Black Hole Merger GW190521," was published in Astrophysical Journal Letters on September 2, 2020: DOI: 10.3847/2041-8213/aba493

The research paper, "GW190814: Gravitational Waves from the Coalescence of a 23 Solar Mass Black Hole with a 2.6 Solar Mass Compact Object," was published in Astrophysical Journal Letters on June 23, 2020.

The research paper, "GW190412: Observation of a Binary-Black-Hole Coalescence with Asymmetric Masses," has been accepted for publication in Physical Review D, and was published on Arxiv on April 17, 2020: arxiv.org/abs/2004.08342

https://phys.org/news/2020-09-heaviest-black-hole-merger-gravitatio...

Comment by Dr. Krishna Kumari Challa on September 2, 2020 at 7:13am

Blood pressure-lowering is even more beneficial than previously thought

Blood pressure medication can prevent heart attacks and strokes -- even in people with normal blood pressure. That's the finding of a meta analysis

https://www.sciencedaily.com/releases/2020/09/200901094058.htm

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Origin of a complex life form revealed

https://phys.org/news/2020-09-complex-life-revealed.html?utm_source...

https://www.quora.com/q/sciencecommunication/Origin-of-a-complex-li...

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Comment by Dr. Krishna Kumari Challa on September 2, 2020 at 7:03am

Blood Replacement Rescues Mice from Stroke Damage

When mice that had suffered a stroke were given blood from a healthy donor, they experienced less tissue and neurological damage.

Researchers have partially mitigated the effects of an ischemic stroke in mice simply by replacing a small amount of their blood with that of a healthy donor. Days after receiving the transplant, mice had less tissue damage surrounding the clot and suffered fewer neurological side effects compared to mice that had not received a blood infusion. 

The results, published August 25 in Nature Communications, highlight the link between strokes in the brain and the immune system. At least some of the damage caused by strokes, the authors say, is the result of an overreactive immune response during which cells sent to an injury to fight infection and facilitate repair instead harm sensitive brain tissue. 

In the moments following a stroke, the body activates a complex immunological response, funneling messenger molecules past the blood-brain barrier and into the blood to recruit immune cells to the damaged area. Neutrophils—white blood cells that are often the first to arrive—increase the levels of an enzyme called MMP-9 that degrades the blood-brain barrier further, the better to allow more immune cells and signaling molecules to pass through. In some instances, the body can release too many of these molecules, such as cytokines, into the blood at once, and the resulting cytokine storm can damage brain tissue surrounding a clot, causing inflammation and degeneration of brain tissue.

To better understand the immunological link between brain and blood, the researchers used a mouse model to mimic an ischemic stroke that was subsequently cleared by the scientists after 90 minutes. Between six and seven hours after the stroke, the mice received a blood transfusion of either 250 or 500 microliters of blood from a healthy donor, roughly 10 percent to 20 percent of a mouse’s total blood volume, after the same volume had been removed from the animal. One hour later, the scientists tested the permeability of the blood-brain barrier, followed by a measure of the amount of damaged brain tissue 24 hours after treatment.

Mice that received blood replacements suffered fewer ill effects than control mice, with the benefits being strongest in the group receiving a larger volume of new blood. The extent of tissue damage surrounding the clot decreased by as much as 70 percent to 80 percent, and cognitive defects brought on by the stroke improved in treated mice. Both the decrease in tissue damage and the rescuing of neurological deficits persisted for at least three days after the initial stroke.

The broader effect of replacing blood seems to be a dampening of the immune response.

https://www.nature.com/articles/s41467-020-17930-x

https://www.the-scientist.com/news-opinion/blood-replacement-rescue...

Comment by Dr. Krishna Kumari Challa on September 2, 2020 at 6:15am

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