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Comment by Dr. Krishna Kumari Challa on September 25, 2020 at 7:48am

Lab uncovers new mechanism of action against SARS-CoV-2 by antiviral drug remdesivir

Researchers  have discovered a novel, second mechanism of action by the antiviral drug remdesivir against SARS-CoV-2

The research team previously demonstrated how remdesivir inhibits the COVID-19 virus's polymerase or replication machinery in a test tube.

Remdesivir stops or heavily delays replication of the virus, which in turn reduces propagation and spread.

 It is not common for antiviral drugs to have more than one mechanism of action. The first mechanism his team uncovered affects what is known as the "primer strand" of RNA or the first copy the virus makes of the viral genome as it infects a cell. The second mechanism affects the "template strand" which is repeated over and over as the virus spreads.

Egor P Tchesnokov et al, Template-dependent inhibition of coronavirus RNA-dependent RNA polymerase by remdesivir reveals a second mechanism of action, Journal of Biological Chemistry (2020). DOI: 10.1074/jbc.AC120.015720

https://phys.org/news/2020-09-lab-uncovers-mechanism-action-sars-co...

Comment by Dr. Krishna Kumari Challa on September 25, 2020 at 6:01am

Air pollution leads to increase in electricity usage, study suggests

High levels of air pollution are forcing people inside to consume more electricity, subsequently causing even greater environmental problems by increasing greenhouse gas emissions.

Pan He et al, Increase in domestic electricity consumption from particulate air pollution, Nature Energy (2020). DOI: 10.1038/s41560-020-00699-0

https://phys.org/news/2020-09-air-pollution-electricity-usage.html?...

Comment by Dr. Krishna Kumari Challa on September 25, 2020 at 5:58am

Gravity causes homogeneity of the universe

Gravity can accelerate the homogenization of space-time as the universe evolves. 

The temporal evolution of the universe, from the Big Bang to the present, is described by Einstein's field equations of general relativity. However, there are still a number of open questions about cosmological dynamics, whose origins lie in supposed discrepancies between theory and observation. One of these open questions is: Why is the universe in its present state so homogeneous on large scales?

It is assumed that the universe was in an extreme state shortly after the Big Bang, characterized in particular by strong fluctuations in the curvature of spacetime. During the long process of expansion, the universe then evolved towards its present state, which is homogeneous and isotropic on large scales—in simple terms: the cosmos looks the same everywhere.

This is inferred, among other things, from the measurement of the so-called background radiation, which appears highly uniform in every direction of observation. This homogeneity is surprising in that even two regions of the universe that were causally decoupled from each other—i.e., they could not exchange information—still exhibit identical values of background radiation.

To resolve this supposed contradiction, the so-called inflation theory was developed, which postulates a phase of extremely rapid expansion immediately after the Big Bang, which in turn can explain the homogeneity in the background radiation.

However, how this phase can be explained in the context of Einstein's theory requires a number of modifications of the theory, which seem artificial and cannot be verified directly.

In the concrete problem, the time evolution of the originally strong deviations from the homogeneous state as cosmological gravitational waves has to be analyzed mathematically. It has to be shown that they decay in the course of the expansion thus allowing the universe to get its homogeneous structure.

Such analyses are based on modern mathematical methods in the field of geometric analysis. Until now, these methods could only achieve such results for small deviations from the homogeneous space-time geometry. David Fajman from the University of Vienna has now succeeded for the first time to transfer these methods to the case of arbitrarily large deviations.

 David Fajman. Future Attractors in 2+1 Dimensional Λ Gravity, Physical Review Letters (2020). DOI: 10.1103/PhysRevLett.125.121102

https://phys.org/news/2020-09-gravity-homogeneity-universe.html?utm...

Comment by Dr. Krishna Kumari Challa on September 25, 2020 at 5:52am

Host-driven evolution: A new strategy of cell entry for some types of parvoviruses

Researchers  have discovered a new parvovirus strategy for reaching the cell nucleus, where they reproduce. The parvoviruses are extremely contagious and persistent in the environment. They are transmitted mainly through the feces of infected invertebrates, vertebrates and mammals including humans. To reach the nucleus of host cells, parvoviruses use mostly enzymatic reactions. They are first absorbed by the cell inside a vesicle, a membrane compartment. To escape, parvoviruses activate a viral enzyme domain called phospholipase A2 (PLA2), a key mechanism.

However, some types of parvoviruses, as well as other nonenveloped viruses, do not have this enzyme domain and must therefore escape from the vesicle by some other means. Using molecular biology and structural studies,  researchers have discovered that a new virus targeting the giant tiger shrimp uses a more mechanical response. This type of parvovirus contains an inner pentamer helix bundle held together by calcium ions. When the microorganism is in the vesicle, where the calcium concentration is decreased by the elimination of toxic substances, the bundle is released and opens up the protein shell (capsid) enclosing its genetic material and the membrane, allowing viral DNA to escape into the nucleus for replication.

Judit J. Pénzes et al, Molecular biology and structure of a novel penaeid shrimp densovirus elucidate convergent parvoviral host capsid evolution, Proceedings of the National Academy of Sciences (2020). DOI: 10.1073/pnas.2008191117

https://phys.org/news/2020-09-strategy-cell-entry-parvoviruses.html...

Comment by Dr. Krishna Kumari Challa on September 25, 2020 at 5:46am

Provide shady spots to protect butterflies from climate change, say scientists

https://phys.org/news/2020-09-shady-butterflies-climate-scientists....

Comment by Dr. Krishna Kumari Challa on September 25, 2020 at 5:44am

Island-building in Southeast Asia created Earth's northern ice sheets

The Greenland ice sheet owes its existence to the growth of an arc of islands in Southeast Asia—stretching from Sumatra to New Guinea—over the last 15 million years, a new study claims.

According to an analysis by researchers as the Australian continent pushed these volcanic islands out of the ocean, the rocks were exposed to rain mixed with carbon dioxide, which is acidic. Minerals within the rocks dissolved and washed with the carbon into the ocean, consuming enough carbon dioxide to cool the planet and allow for large ice sheets to form over North America and Northern Europe.

Yuem Park el al., "Emergence of the Southeast Asian islands as a driver for Neogene cooling," PNAS (2020). www.pnas.org/cgi/doi/10.1073/pnas.2011033117

https://phys.org/news/2020-09-island-building-southeast-asia-earth-...

Comment by Dr. Krishna Kumari Challa on September 25, 2020 at 5:41am

Glass molecules can act like sand when jammed, study finds

Researchers have discovered that molecules in glass materials behave just like particles in sand and rocks as they jam together, a mechanism that could boost explorations of condensed matter and complex systems.

The work shows that glassy materials change their organizational structure to behave like sand when they are jammed, or compressed to the point of changing from liquid to rigid. The discovery expands the understanding of thermal motion and vibrational states that occur as materials reach jamming.

Francesco Arceri et al. Vibrational Properties of Hard and Soft Spheres Are Unified at Jamming, Physical Review Letters (2020). DOI: 10.1103/PhysRevLett.124.238002

https://phys.org/news/2020-09-glass-molecules-sand.html?utm_source=...

Comment by Dr. Krishna Kumari Challa on September 25, 2020 at 5:37am

Twinkling, star-shaped brain cells may hold the key to why, how we sleep

A new study published  suggests that star-shaped brain cells known as astrocytes could be as important to the regulation of sleep as neurons, the brain's nerve cells.

The study builds new momentum toward ultimately solving the mystery of why we sleep and how sleep works in the brain. The discovery may also set the stage for potential future treatment strategies for sleep disorders and neurological diseases and other conditions associated with troubled sleep, such as PTSD, depression, Alzheimer's disease, and autism spectrum disorder.

What we know about sleep has been based largely on neurons. Neurons communicate through electrical signals that can be readily captured through electroencephalography (EEG). Astrocytes—a type of glial (or "glue") cell that interacts with neurons—do not use electrical signals and instead use a process known as calcium  signaling to control their activity.

Looking at astrocytes in the frontal cortex, an area of the brain associated with measurable EEG changes in sleep need, researchers found that astrocytes' activity changes dynamically across the sleep-wake cycle, as is true for neurons. They also observed the most calcium activity at the beginning of the rest phase—when sleep need is greatest—and the least calcium activity at the end of the test phase, when the need for sleep has dissipated.

they also found that sleep deprivation caused an increase in astrocyte calcium activity that decreased after mice were allowed to sleep.

This indicates to us that astrocytes are not just passively following the lead of neurons," said Ingiosi. "And because they don't necessarily display the same activity patterns as neurons, this might actually implicate a more direct role for astrocytes in regulating sleep and sleep need."

 Current Biology (2020). DOI: 10.1016/j.cub.2020.08.052 , www.cell.com/current-biology/f … 0960-9822(20)31242-2

https://medicalxpress.com/news/2020-09-twinkling-star-shaped-brain-...

Comment by Dr. Krishna Kumari Challa on September 25, 2020 at 5:28am

New brain cell-like nanodevices work together to identify mutations in viruses

In a recent paper publication, scientists have described a new nanodevice that acts almost identically to a brain cell. Furthermore, they have shown that these synthetic brain cells can be joined together to form intricate networks that can then solve problems in a brain-like manner. This is the first study where they have been able to emulate a neuron with just a single nanoscale device.

In particular, the researchers have demonstrated proof of concept that their brain-inspired system can identify possible mutations in a virus, which is highly relevant for ensuring the efficacy of vaccines and medications for strains exhibiting genetic diversity.

Suhas Kumar et al, Third-order nanocircuit elements for neuromorphic engineering, Nature (2020). DOI: 10.1038/s41586-020-2735-5

https://phys.org/news/2020-09-brain-cell-like-nanodevices-mutations...

Comment by Dr. Krishna Kumari Challa on September 24, 2020 at 12:07pm

Magnetic ‘T-Budbots’ kill and clean biofilms

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