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Comment by Dr. Krishna Kumari Challa on November 11, 2020 at 8:29am

A new candidate material for Quantum Spin Liquids

 In 1973, physicist and later Nobel laureate Philip W. Anderson proposed a bizarre state of matter: the quantum spin liquid (QSL). Unlike the everyday liquids we know, the QSL actually has to do with magnetism – and magnetism has to do with spin.

What makes a magnet? It was a long-lasting mystery, but today we finally know that magnetism arises from a peculiar property of sub-atomic particles, like electrons. That property is called “spin”, and the best – yet grossly insufficient – way to think of it is like a child’s spinning-top toy.

What is important for magnetism is that spin turns every one of a material’s billions of electrons into a tiny magnet with its own magnetic “direction” (think north and south pole of a magnet). But the electron spins aren’t isolated; they interact with each other in different ways until they stabilize to form various magnetic states, thereby granting the material they belong to magnetic properties.

In a conventional magnet, the interacting spins stabilize, and the magnetic directions of each electron align. This results in a stable formation.

But in what is known as a “frustrated” magnet, the electron spins can’t stabilize in the same direction. Instead, they constantly fluctuate like a liquid – hence the name “quantum spin liquid.”

What is exciting about QSLs is that they can be used in a number of applications. Because they come in different varieties with different properties, QSLs can be used in quantum computing, telecommunications, superconductors, spintronics (a variation of electronics that uses electron spin instead of current), and a host of other quantum-based technologies.

But before exploiting them, we first have to gain a solid understanding of QSL states. To do this, scientists have to find ways to produce QSLs on demand.

 Scientists have successfully produced and studied a QSL in a highly original material known as EDT-BCO.

The structure of EDT-BCO is what makes it possible to create a QSL. The electron spins in the EDT-BCO form triangularly organized dimers, each of which has a spin-1/2 magnetic moment which means that the electron must fully rotate twice to return to its initial configuration. The layers of spin-1/2 dimers are separated by a sublattice of carboxylate anions centred by a chiral bicyclooctane. The anions are called “rotors” because they have conformational and rotational degrees of freedom.

The unique rotor component in a magnetic system makes the material special amongst QSL candidates, representing a new material family. “The subtle disorder provoked by the rotor components introduces a new handle upon the spin system.

The scientists and their collaborators employed an arsenal of methods to explore the EDT-BCO as a QSL material candidate: density functional theory calculations, high-frequency electron spin resonance measurements, nuclear magnetic resonance, and muon spin spectroscopy. All of these techniques explore the magnetic properties of EDT-BCO from different angles.

All the techniques confirmed the absence of long-range magnetic order and the emergence of a QSL. In short, EDT-BCO officially joins the limited ranks of QSL materials and takes us a step further into the next generation of technologies.

https://actu.epfl.ch/news/a-new-candidate-material-for-quantum-spin...

https://researchnews.cc/news/3511/A-new-candidate-material-for-Quan...

Comment by Dr. Krishna Kumari Challa on November 11, 2020 at 8:01am

Why bats fly into walls

Bats excel in acoustic perception and detect objects as tiny as mosquitoes using sound waves. Echolocation permits them to calculate the three-dimensional location of both small and large objects, perceiving their shape, size and texture. To this end, a bat's brain processes acoustic dimensions such as frequency, spectrum and intensity from the echoes returning from the object.

But sometimes bats collide with large walls even though they detect these walls with their sonar system. Researchers from Tel Aviv University (TAU) have concluded that these collisions do not result from a sensory limitation but rather from an error in acoustic perception.

 The researchers discovered that the bats collided with large sponge walls that produce a weak echo as if they did not exist. The bats' behaviour suggested that they did this even though they had detected the wall with their sonar system, indicating that the collision did not result from a sensory limitation, but rather from an acoustic misperception.

The researchers hypothesize that the unnatural combination of a large object and a weak echo disrupts the bats' sensory perception and causes them to ignore the obstacle, much like people who bump into transparent walls.

The researchers then methodically changed the features of the objects along the corridor, varying their size, texture and echo intensity. They concluded that the bats' acoustic perception depends on a coherent, typical correlation of the dimensions with objects in nature—that a large object should produce a strong echo and a small object a weak echo.

By presenting the bats with objects whose acoustic dimensions are not coherent, we were able to mislead them, creating a misconception that caused them to repeatedly try to fly into a wall even though they had identified it with their sonar. The experiment gives us a peek into how the world is perceived by these creatures, whose senses are so unique and different from ours.

Sasha Danilovich et al, Echolocating bats detect but misperceive a multidimensional incongruent acoustic stimulus, Proceedings of the National Academy of Sciences (2020). DOI: 10.1073/pnas.2005009117

https://phys.org/news/2020-11-walls.html

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Fruit bats can transform echoes into images

https://phys.org/news/2019-06-fruit-echoes-images.html

Comment by Dr. Krishna Kumari Challa on November 11, 2020 at 7:53am

Study identifies new 'hidden' gene in COVID-19 virus

Researchers have discovered a new "hidden" gene in SARS-CoV-2—the virus that causes COVID-19—that may have contributed to its unique biology and pandemic potential. In a virus that only has about 15 genes in total, knowing more about this and other overlapping genes—or "genes within genes"—could have a significant impact on how we combat the virus.

Overlapping genes may be one of an arsenal of ways in which coronaviruses have evolved to replicate efficiently, thwart host immunity, or get themselves transmitted. Knowing that overlapping genes exist and how they function may reveal new avenues for corona virus control, for example through antiviral drugs.

The research team identified ORF3d, a new overlapping gene in SARS-CoV-2 that has the potential to encode a protein that is longer than expected by chance alone. They found that this gene is also present in a previously discovered pangolin coronavirus, perhaps reflecting repeated loss or gain of this gene during the evolution of SARS-CoV-2 and related viruses. In addition, ORF3d has been independently identified and shown to elicit a strong antibody response in COVID-19 patients, demonstrating that the new gene's protein is manufactured during human infection.

Chase W Nelson et al, Dynamically evolving novel overlapping gene as a factor in the SARS-CoV-2 pandemic, eLife (2020). DOI: 10.7554/eLife.59633

https://phys.org/news/2020-11-hidden-gene-covid-virus.html

Comment by Dr. Krishna Kumari Challa on November 11, 2020 at 7:46am

Scientists have discovered an ancient lake bed deep beneath the Greenland ice

Scientists have detected what they say are the sediments of a huge ancient lake bed sealed more than a mile under the ice of northwest Greenland—the first-ever discovery of such a sub-glacial feature anywhere in the world. Apparently formed at a time when the area was ice-free but now completely frozen in, the lake bed may be hundreds of thousands or millions of years old, and contain unique fossil and chemical traces of past climates and life. 

Guy J.G. Paxman et al. A fault-bounded palaeo-lake basin preserved beneath the Greenland Ice Sheet, Earth and Planetary Science Letters (2020). DOI: 10.1016/j.epsl.2020.116647

https://phys.org/news/2020-11-scientists-ancient-lake-bed-deep.html...

Comment by Dr. Krishna Kumari Challa on November 11, 2020 at 7:36am

Scientists use bacteria as micro-3-D printers

A team at Aalto University has used bacteria to produce intricately designed three-dimensional objects made of nanocellulose. With their technique, the researchers are able to guide the growth of bacterial colonies through the use of strongly water repellent—or superhydrophobic—surfaces. The objects show tremendous potential for medical use, including supporting tissue regeneration or as scaffolds to replace damaged organs.

Unlike fibrous objects made through current 3-D printing methods, the new technique allows fibers, with a diameter a thousand times thinner than a human hair, to be aligned in any orientation, even across layers, and various gradients of thickness and topography, opening up new possibilities for application in tissue regeneration. These kinds of physical characteristics are crucial for support materials in the growth and regeneration of certain types of tissues found in muscles as well as in the brain.

Luiz G. Greca et al, Guiding Bacterial Activity for Biofabrication of Complex Materials via Controlled Wetting of Superhydrophobic Surfaces, ACS Nano (2020). DOI: 10.1021/acsnano.0c03999

https://phys.org/news/2020-11-scientists-bacteria-micro-d-printers....

Comment by Dr. Krishna Kumari Challa on November 11, 2020 at 7:32am

Nanomedicine crosses into brain, eradicates recurring brain cancer in mice

A new synthetic protein nanoparticle capable of slipping past the nearly impermeable blood-brain barrier could deliver cancer-killing drugs directly to malignant brain tumours, new research  shows.

The study is the first to demonstrate an intravenous medication that can cross the blood-brain barrier.

The discovery, demonstrated in mice, could enable new clinical therapies for treating glioblastoma, the most common and aggressive form of brain cancer in adults, and one whose incidence is rising in many countries.T oday's median survival for patients with glioblastoma is around 18 months; the average 5-year survival rate is below 5%.

In combination with radiation, the U-M team's intravenously-injected therapy led to long-term survival in seven out of eight mice. When those seven mice experienced a recurrence of glioblastoma, their immune responses kicked in to prevent the cancer's regrowth—without any additional therapeutic drugs or other clinical treatments.

The findings suggest that the U-M team's combination of therapeutic drugs and nanoparticle delivery methods not only eradicated the primary  tumour but resulted in immunological memory, or the ability to more quickly recognize—and attack—remaining malignant cancer cells.

Jason V. Gregory et al. Systemic brain tumor delivery of synthetic protein nanoparticles for glioblastoma therapy, Nature Communications (2020). DOI: 10.1038/s41467-020-19225-7

https://phys.org/news/2020-11-nanomedicine-brain-eradicates-recurri...

Comment by Dr. Krishna Kumari Challa on November 11, 2020 at 6:55am

Chemicals in your living room cause diabetes

A new  study shows flame retardants  in  homes cause mice to give birth to offspring that become diabetic.

PBDEs are common household chemicals added to furniture, upholstery, and electronics to prevent fires. They get released into the air people breathe at home, in their cars, and in airplanes because their chemical bond to surfaces is weak.

"PBDEs are everywhere in the home. They're impossible to completely avoid

These flame retardants, called PBDEs, have been associated with diabetes in adult humans. This study demonstrates that PBDEs cause diabetes in mice only exposed to the chemical through their mothers.

The mice received PBDEs from their mothers while they were in the womb and as young babies through mother's milk. Remarkably, in adulthood, long after the exposure to the chemicals, the female offspring developed diabetes.

Elena V. Kozlova et al, Maternal transfer of environmentally relevant polybrominated diphenyl ethers (PBDEs) produces a diabetic phenotype and disrupts glucoregulatory hormones and hepatic endocannabinoids in adult mouse female offspring, Scientific Reports (2020). DOI: 10.1038/s41598-020-74853-9

https://medicalxpress.com/news/2020-11-chemicals-room-diabetes.html...

Comment by Dr. Krishna Kumari Challa on November 11, 2020 at 6:30am

Researchers isolate and decode brain signal patterns for specific behaviours

Brain signals contain dynamic neural patterns that reflect a combination of  activities simultaneously. A standing challenge has been isolating those patterns in brain signals that relate to a specific behaviour, such as finger movements. Further, developing brain-machine interfaces (BMIs) that help people with neurological and mental disorders requires the translation of brain signals into a specific behaviour, a problem called decoding. This decoding also depends on our ability to isolate neural patterns related to specific behaviours. These neural patterns can be masked by patterns related to other activities and can be missed by standard algorithms.

Researchers have developed a machine learning algorithm that resolved the above challenge. The algorithm  uncovered neural patterns missed by other methods and enhanced the decoding of behaviours that originated from signals in the brain. This algorithm is a significant advance in modeling and decoding of complex brain activity which could both enable new neuroscience discoveries and enhance future brain-machine interfaces.

Modeling behaviorally relevant neural dynamics enabled by preferential subspace identification, Nature Neuroscience (2020). DOI: 10.1038/s41593-020-00733-0 , www.nature.com/articles/s41593-020-00733-0

https://medicalxpress.com/news/2020-11-isolate-decode-brain-pattern...

Comment by Dr. Krishna Kumari Challa on November 11, 2020 at 6:08am

Radioactive elements may be crucial to the habitability of rocky planets

The amount of long-lived radioactive elements incorporated into a rocky planet as it forms may be a crucial factor in determining its future habitability, according to a new study by an interdisciplinary team of scientists.

 That's because internal heating from the radioactive decay of the heavy elements thorium and uranium drives plate tectonics and may be necessary for the planet to generate a magnetic field. Earth's magnetic field protects the planet from solar winds and cosmic rays.

Convection in Earth's molten metallic core creates an internal dynamo (the "geodynamo") that generates the planet's magnetic field. Earth's supply of radioactive elements provides more than enough internal heating to generate a persistent geodynamo.

Different planets accumulate different amounts of these radioactive elements that ultimately power geological activity and the magnetic field. I

if the radiogenic heating is more than the Earth's, the planet can't permanently sustain a dynamo, as Earth has done. That happens because most of the thorium and uranium end up in the mantle, and too much heat in the mantle acts as an insulator, preventing the molten core from losing heat fast enough to generate the convective motions that produce the magnetic field.

With more radiogenic internal heating, the planet also has much more volcanic activity, which could produce frequent mass extinction events. On the other hand, too little radioactive heat results in no volcanism and a geologically "dead" planet.

It has long been speculated that internal heating drives plate tectonics, which creates carbon cycling and geological activity like volcanism, which produces an atmosphere. And the ability to retain an atmosphere is related to the magnetic field, which is also driven by internal heating.

The heavy elements crucial to radiogenic heating are created during mergers of neutron stars, which are extremely rare events. 

 Francis Nimmo et al. Radiogenic Heating and Its Influence on Rocky Planet Dynamos and Habitability, The Astrophysical Journal (2020). DOI: 10.3847/2041-8213/abc251

https://phys.org/news/2020-11-radioactive-elements-crucial-habitabi...

Comment by Dr. Krishna Kumari Challa on November 10, 2020 at 10:17am

First-Ever Flu Vaccine Derived From Tobacco Plants Just Smashed Clinical Trials

A new flu vaccine grown in plants has been put to the test in two large-scale clinical trials, a first for vaccine research.

The vaccine contained virus-like particles which resembled circulating flu strains, extracted from native Australian tobacco relatives that were genetically instructed to produce the viral proteins.

The two trials combined involved nearly 23,000 people and the results suggest that the plant-derived vaccine is not only safe, but comparable to current commercial flu vaccines.

To the best of our knowledge, these studies and the clinical development programme that preceded them are the largest demonstration to date of the potential for a plant-based platform to produce a human vaccine that can be safe, immunogenic, and effective.

Most influenza vaccines are currently made using virus particles grown in and harvested from chicken eggs or lab-grown cells, which takes months even after scientists work out which flu strains (and surface proteins) they need to target.

Plants, which can be engineered to produce select proteins and cultivated at scale, could be an alternative, helping to boost our capacity to produce seasonal flu vaccines.

https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)32014-6/fulltext

https://www.sciencealert.com/large-scale-studies-test-flu-vaccine-d...

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