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Comment by Dr. Krishna Kumari Challa on May 28, 2021 at 1:43pm

Physicists Have Broken The Speed of Light With Pulses Inside Hot Plasma

Physicists have been playing hard and fast with the speed limit of light pulses for a while, speeding them up and even slowing them to a virtual stand-still using various materials like cold atomic gases, refractive crystals, and optical fibers.

This time, researchers from Lawrence Livermore National Laboratory in California and the University of Rochester in New York have managed it inside hot swarms of charged particles, fine-tuning the speed of light waves within plasma to anywhere from around one-tenth of light's usual vacuum speed to more than 30 percent faster.

This is both more – and less – impressive than it sounds.

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.126.205001

https://www.newscientist.com/article/2278564-laser-pulses-travel-fa...

Comment by Dr. Krishna Kumari Challa on May 28, 2021 at 1:22pm

Bees Opening a Soda Bottle

'Unbelievable' Video Shows Two Bees Work Together to Unscrew a Soda...

Bees Opening a Soda Bottle

Two Bees Work Together to Unscrew a Soda Bottle

Comment by Dr. Krishna Kumari Challa on May 28, 2021 at 1:11pm

Brain Computer Interface Turns Mental Handwriting into Text on Screen

Researchers have, for the first time, decoded the neural signals associated with writing letters, then displayed typed versions of those letters in real time. They hope their invention could one day help people with paralysis communicate.

Comment by Dr. Krishna Kumari Challa on May 28, 2021 at 12:47pm

Had COVID? You’ll probably make antibodies for a lifetime

People who recover from mild COVID-19 have bone-marrow cells that can churn out antibodies for decades, though viral variants could dampen some of the protection they offer.

Many people who have been infected with SARS-CoV-2 will probably make antibodies against the virus for most of their lives. So suggest researchers who have identified long-lived antibody-producing cells in the bone marrow of people who have recovered from COVID-19.

The study provides evidence that immunity triggered by SARS-CoV-2 infection will be extraordinarily long-lasting. Adding to the good news, the implications are that vaccines will have the same durable effect.

team tracked antibody production in 77 people who recovered from mostly mild cases of COVID-19. As expected, SARS-CoV-2 antibodies plummeted in the four months after infection. But this decline slowed, and up to eleven months after infection, the researchers could still detect antibodies that recognized the SARS-CoV-2 spike protein.

Turner, J. S. et al. Nature https://doi.org/10.1038/s41586-021-03647-4 (2021).

Comment by Dr. Krishna Kumari Challa on May 28, 2021 at 11:58am

part 2

So the researchers tried something unorthodox: they rapidly inverted the spin of one of the two atoms with a sudden burst of electric current. To their surprise, this drastic approach resulted in a beautiful quantum interaction, exactly by the book. During the pulse, electrons collide with the atom, causing its spin to rotate.

The electron inverts the spin of one atom causing it to point, say, to the left. You could view this as a measurement, erasing all quantum memory. But from the point of view of the combined system comprising both atoms, the resulting situation is not so mundane at all. For the two atoms together, the new state constitutes a perfect superposition, enabling the exchange of information between them. Crucially for this to happen is that both spins become entangled: a peculiar quantum state in which they share more information about each other than classically possible."

The discovery can be of importance to research on quantum bits. Perhaps also in that research you could get away with being slightly less careful when initializing quantum states. 

"Free coherent evolution of a coupled atomic spin system initialized by electron scattering" Science (2021). science.sciencemag.org/cgi/doi … 1126/science.abg8223

https://phys.org/news/2021-05-scientists-atoms-chatting.html?utm_so...

Comment by Dr. Krishna Kumari Challa on May 28, 2021 at 11:56am

Scientists overhear two atoms chatting

How materials behave depends on the interactions between countless atoms. You could see this as a giant group chat in which atoms are continuously exchanging quantum information. Researchers  have now been able to intercept a chat between two atoms. They present their findings in Science on 28 May.

Atoms, of course, don't really talk. But they can react to each other. This is particularly the case for magnetic atoms. "Each atom carries a small magnetic moment called spin. These spins influence each other, like compass needles do when you bring them close together. If you give one of them a push, they will start moving together in a very specific way.

But according to the laws of quantum mechanics, each spin can be simultaneously point in various directions, forming a superposition. This means that actual transfer of quantum information takes place between the atoms, like some sort of conversation.

On a large scale, this kind of exchange of information between atoms can lead to fascinating phenomena. A classic example is superconductivity: the effect where some materials lose all electrical resistivity below a critical temperature. While well understood for the simplest cases, nobody knows exactly how this effect comes about in many complex materials. But it's certain that magnetic quantum interactions play a key role. For the purpose of trying to explaining phenomena like this, scientists are very interested in being able to intercept these exchanges; to overhear the conversations between atoms.

Scientists  literally put two atoms next to each other to see what happens. This is possible by virtue of a scanning tunneling microscope: a device in which a sharp needle can probe atoms one-by-one and can even rearrange them. The researchers used this device to place two titanium atoms at a distance of just over one nanometer—one millionth of a millimeter—apart. At that distance, the atoms are just able to detect each other's spin. If you would now twist one of the two spins, the conversation would start by itself.

Usually, this twist is performed by sending very precise radio signals to the atoms. This so-called spin resonance technique—which is quite reminiscent of the working principle of an MRI scanner found in hospitals—is used successfully in research on quantum bits. You have barely started twisting the one spin before the other starts to rotate along. This way you can never investigate what happens upon placing the two spins in opposite directions

Comment by Dr. Krishna Kumari Challa on May 28, 2021 at 11:51am

Research team discovers that it takes some heat to form ice on graphene

In a paper published in Nature Communications, the research team details the complex physical processes at work to understand the chemistry of ice formation. The molecular-level perspective of this process may help in predicting the formation and melting of ice, from individual crystals to glaciers and ice sheets. The latter being crucial to quantify environmental transformation in connection with climate change and global warming.

The team was able to track down the first step in ice formation, called nucleation, which happens in an incredibly short length of time, a fraction of a billionth of a second, when highly mobile individual water molecules find each other and coalesce. However, conventional microscopes are far too slow to follow the motion of water molecules, so it is impossible to use them to monitor how molecules combine on top of solid surfaces.

Anton Tamtögl et al, Motion of water monomers reveals a kinetic barrier to ice nucleation on graphene, Nature Communications (2021). DOI: 10.1038/s41467-021-23226-5

https://phys.org/news/2021-05-team-ice-graphene.html?utm_source=nwl...

Comment by Dr. Krishna Kumari Challa on May 28, 2021 at 10:39am

Research team discovers that it takes some heat to form ice on grap...

In a paper published in Nature Communications, the research team details the complex physical processes at work to understand the chemistry of ice formation. The molecular-level perspective of this process may help in predicting the formation and melting of ice, from individual crystals to glaciers and ice sheets. The latter being crucial to quantify environmental transformation in connection with climate change and global warming.

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Virus transmission: New animation gives insight to viral spread

How can an influenza virus transfer from animals to humans even though the molecules on which they land at the cell surface are different? To find out, researchers of the University of Twente developed a sensor chip that mimics the cell surface and has an increasing number of binding sites along the way. The virus rolls across the surface until the binding is strong enough. For visualizing and better understanding of the mechanisms involved, the researchers created an animation, together with Dutch veterinary lab Royal GD.

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Cell mechanics research is making chemotherapy friendlier

Malignant tumor cells undergo mechanical deformation more easily than normal cells, allowing them to migrate throughout the body. The mechanical properties of prostate cancer cells treated with the most commonly used anti-cancer drugs have been investigated at the Institute of Nuclear Physics of the Polish Academy of Sciences in Cracow. According to the researchers, current drugs can be used more effectively and at lower doses.

Comment by Dr. Krishna Kumari Challa on May 28, 2021 at 10:32am

Global study of 60 cities' microbes finds each has a signature microbial fingerprint

An international consortium has reported the largest-ever global metagenomic study of urban microbiomes, spanning both the air and the surfaces of multiple cities. The international project, which sequenced and analyzed samples collected from public transit systems and hospitals in 60 cities around the world, features comprehensive analysis and annotation for all the microbial species identified—including thousands of viruses and bacteria and two archaea not found in reference databases. The study appears May 26 in the journal Cell.

Every city has its own 'molecular echo' of the microbes that define it.

The findings are based on 4,728 samples from cities on six continents taken over the course of three years, characterize regional antimicrobial resistance markers, and represent the first systematic worldwide catalogue of the urban microbial ecosystem. In addition to distinct microbial signatures in various cities, the analysis revealed a core set of 31 species that were found in 97% of samples across the sampled urban areas. The researchers identified 4,246 known species of urban microorganisms, but they also found that any subsequent sampling will still likely continue to find species that have never been seen before, which highlights the raw potential for discoveries related to microbial diversity and biological functions awaiting in urban environments.

Cell, Danko et al.: "A global metagenomic map of urban microbiomes and antimicrobial resistance" www.cell.com/cell/fulltext/S0092-8674(21)00585-7 , DOI: 10.1016/j.cell.2021.05.002

A related paper ("Characterization of the public transit air microbiome and resistome reveals geographical specificity") publishes in the journal Microbiome on May 26.

https://phys.org/news/2021-05-global-cities-microbes-signature-micr...

Comment by Dr. Krishna Kumari Challa on May 28, 2021 at 10:28am

How plants ward off a dangerous world of pathogens

The world's plants, immobile and rooted in soil which contains potentially lethal micro-organisms, face a constant threat from invading pathogens. In recent years, however, scientists have discovered that plant species employ sophisticated immune strategies that differ from —but also shares similarities with—the ways humans combat infections.

Now scientists describe a key molecular "on-off" switch that enables plants to mobilize immunity in the face of microbial pathogens. The findings not only have direct implications for crop management and possibly protecting plants from the effects of climate change, but also for better understanding the human immune system as well.

Plants  have many innate immune gene families that are similar to ours, and historically plants have been used to establish fundamental principles of host defenses and disease tolerance.

Unlike humans, plants lack an adaptive immune system that "remembers" specific pathogens and then organizes a tailored defense. In the study, researchers explored the sophisticated cell-autonomous defense programs that plants do employ against pathogens. It turns out that what they lack in tailored antibodies, they make up for by greatly expanding their repertoire of innate immune responses, which mount a more generalized defense against all infections.

For instance, one of these strategies involves innate immune proteins that morph into a "gel-like" state in order to trigger immune responses. This process—called liquid-liquid phase separation—enables biological activities to be concentrated in membrane-less compartments inside cells. The researchers discovered that plant immune proteins, known as guanylate-binding protein-like (GBPL) GTPases, create liquid-like compartments within the nucleus that creates a concentration of proteins that drive the activity of host defense genes during infection. This phase-separated compartment also excludes inhibitory proteins to the outside of the nucleus as part of a spatially separated "on-off" switch.

Liquid-liquid phase separation is a new frontier in understanding how cells compartmentalize their biological activities.

All organisms, from single-celled bacteria to plants  to humans, defend their genome from outside threats. "Phase-separation may be a pervasive evolutionary mechanism to organize these defense activities as part of the cell-autonomous immune response."

Shuai Huang et al, A phase-separated nuclear GBPL circuit controls immunity in plants, Nature (2021). DOI: 10.1038/s41586-021-03572-6

https://phys.org/news/2021-05-ward-dangerous-world-pathogens.html?u...

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