Comment

Comment by Dr. Krishna Kumari Challa on December 9, 2021 at 9:18am

Comment by Dr. Krishna Kumari Challa on December 8, 2021 at 11:13am

Scientists Observe Quantum Spin Liquids: A State of Matter We've Never Seen Before

An exotic and totally new state of matter called a quantum spin liquid has been hypothesized for decades, and now scientists have been able to observe it in a laboratory for the first time.

The 'liquid' part refers to electrons that are constantly changing and fluctuating inside a magnetic material at low temperatures. Unlike regular magnets, in this case the electrons don't stabilize or settle into the structured lattice of a solid as they are cooled.

The 'quantum spin' refers to orientation of angular momentum (up or down) carried by particles, which are entangled in pairs with opposing spins. Now that the state has been observed for the first time, it's hoped that the discovery can advance progress in the development of quantum computers.

Normal magnets feature electrons whose spin is orientated in the same direction either up or down, which is what generates magnetism.

In quantum spin liquids, a third electron is introduced, so while two opposing spins will stabilize each other, the spin from the third electron throws out the balance. It creates a 'frustrated' magnet where the spins can't all stabilize in one direction.

To produce their own frustrated lattice pattern, the team used a programmable quantum simulator built in 2017. The simulator uses a quantum computer program to hold atoms in custom shapes using lasers – like squares, triangles, or honeycombs – and can be used to engineer different quantum interactions and processes.

The simulator uses tightly focussed laser beams to arrange atoms individually, and by arranging the atoms of rubidium in a triangle-patterned lattice the researchers were able to produce a frustrated magnet with properties of quantum entanglement – where changes in one atom are matched in a second entangled atom.

The connections between the atoms indicated that a quantum spin liquid had indeed been created.

https://www.science.org/doi/10.1126/science.abi8794

https://www.sciencealert.com/scientists-document-quantum-spin-liqui...

Comment by Dr. Krishna Kumari Challa on December 8, 2021 at 10:58am

The World's Most Dangerous Blood Type

Comment by Dr. Krishna Kumari Challa on December 8, 2021 at 9:52am

No airplane carries oxygen tanks to feed your masks! Then how do you get oxygen?

This video tells how and  also how oxygen masks brought down  a plane

Comment by Dr. Krishna Kumari Challa on December 8, 2021 at 9:37am

Evidence emerges for dark-matter free galaxies

 An international team of astronomers has found no trace of dark matter in the galaxy AGC 114905, despite taking detailed measurements over a course of forty hours with state-of-the-art telescopes.

When Researchers discovered six galaxies with little to no dark matter, they were told "measure again, you'll see that there will be dark matter around your galaxy". However, after forty hours of detailed observations using the Very Large Array (VLA) in New Mexico (United States), the evidence for a dark matter-free galaxy only became stronger.

The galaxy in question, AGC 114905, is about 250 million light-years away. It is classified as an ultra-diffuse dwarf galaxy, with the name 'dwarf galaxy' referring to its luminosity and not to its size. The galaxy is about the size of our own Milky Way but contains a thousand times fewer stars. The prevailing idea is that all galaxies, and certainly ultra-diffuse dwarf galaxies, can only exist if they are held together by dark matter.

The researchers collected data on the rotation of gas in AGC 114905 for 40 hours between July and October 2020 using the VLA telescope. Subsequently, they made a graph showing the distance of the gas from the center of the galaxy on the x-axis and the rotation speed of the gas on the y-axis. This is a standard way to reveal the presence of dark matter. The graph shows that the motions of the gas in AGC 114905 can be completely explained by just normal matter.

In their scientific publication, the researchers list the possible explanations for the lack of dark matter one by one. For example, AGC 114905 could have been stripped of dark matter by large nearby galaxies.

But there are none. And in the most reputed galaxy formation framework, the so called cold dark matter model, they would have to introduce extreme parameter values that are far beyond the usual range. Also with modified Newtonian dynamics, an alternative theory to cold dark matter, they cannot reproduce the motions of the gas within the galaxy.

According to the researchers, there is one more assumption that could change their conclusions. That is the estimated angle at which they think they are observing the galaxy. But that angle has to deviate very much from their estimate before there is room for dark matter again.

Meanwhile, the researchers are examining a second ultra-diffuse dwarf galaxy in detail. If again observe no trace of dark matter in that galaxy, it will make the case for dark matter poor galaxies even stronger.

https://researchnews.cc/news/10404/Evidence-emerges-for-dark-matter...

**

Comment by Dr. Krishna Kumari Challa on December 8, 2021 at 9:10am

Transverse sound wave discovered

The physics textbooks tell us there are two kinds of waves. In transverse waves like light, the vibrations are perpendicular to the direction of wave propagation. In longitudinal waves like sound, the vibrations are parallel to the direction of wave propagation. But the latest discovery by scientists  changes this understanding of sound waves.

Imagine sound traveling in the same way as light does.

A research team  has discovered a new type of sound wave: The airborne sound wave vibrates transversely and carries both spin and orbital angular momentum like light does. The findings shattered scientists' previous thinking about the sound wave, opening an avenue to the development of novel applications in acoustic communications, acoustic sensing and imaging.

While the airborne sound is a longitudinal wave in usual cases,  this new study demonstrated for the first time that it can be a transverse wave under certain conditions. And physicists  investigated its spin-orbit interactions (an important property only exists in transverse waves), i.e. the coupling between two types of angular momentum. The finding provides new degrees of freedom for sound manipulations.

The absence of shear force in the air, or fluids, is the reason why sound is a longitudinal wave .  Researchers had been exploring whether it is possible to realize transverse sound, which requires shear force. Then they conceived the idea that synthetic shear force may arise if the air is discretized into "meta-atoms," i.e., volumetric air confined in small resonators with size much smaller than the wavelength. The collective motion of these air "meta-atoms" can give rise to a transverse sound on the macroscopic scale.

Shubo Wang et al, Spin-orbit interactions of transverse sound, Nature Communications (2021). DOI: 10.1038/s41467-021-26375-9

https://phys.org/news/2021-12-physicists-special-transverse.html?ut...

Comment by Dr. Krishna Kumari Challa on December 8, 2021 at 9:02am

Researchers develop a world-first antibody-drug delivery system

Imagine this: a man-made crystal that can be attached to antibodies and then supercharge them with potent drugs or imaging agents that can seek out diseased cells with the highest precision, resulting in fewer adverse effects for the patient.

That is precisely what researchers  have developed: the world's first metal-organic framework (MOFs) antibody-drug delivery system that has the potential to fast-track potent new therapies for cancer, cardiovascular and auto-immune diseases.

The in vitro study showed that when MOF antibody crystals bind to their target cancer cells and if exposed to the low pH in the cells, they break down, delivering the drugs directly and solely to the desired area.   

The metal-organic framework, a mixture of metal (zinc) and carbonate ions, and a small organic molecule (an imidazole, a colorless solid compound that is soluble in water) not only keeps the payload attached to the antibody but can also acts as a reservoir of personalized therapeutics. This is a benefit with the potential to become a new medical tool to target specific diseases with customized drugs and optimized doses.

With just 0.01 per cent of chemotherapy currently reaching the cancer tissue, this revolutionary new method can boost the potency of the drugs reaching their target.

With over 80 different monoclonal antibodies approved for clinical use, this approach has enormous potential to improve these antibodies for the targeted delivery of diagnostic agents and therapeutic drugs. The goal is that ultimately the clinical translation of this technology will improve the quality of life for patients suffering from serious diseases.

Karen Alt et al, Self‐Assembly of Oriented Antibody‐Decorated Metal‐Organic Framework Nanocrystals for Active Targeting Applications, Advanced Materials (2021). DOI: 10.1002/adma.202106607

https://phys.org/news/2021-12-world-first-antibody-drug-delivery.ht...

Comment by Dr. Krishna Kumari Challa on December 8, 2021 at 8:54am

How SARS-CoV-2 evades the immune system

Researchers have found SARS-CoV-2 can knock out an important molecular pathway linked to an immune complex called MHC class I. The finding should help scientists better understand how COVID-19 infection takes hold.

Scientists used a bioinformatics approach to look at how SARS-CoV-2, the virus that causes COVID-19, changes gene expression in the immune systems of COVID-19 patients compared to uninfected individuals. This is a useful way to look into the function of complicated cell signaling pathways that trigger immune responses to fight off harmful bacteria and viruses.

MHC (major histocompatibility complex) class I molecules are a central weapon in the immune response against viruses. When a virus infects a cell, the cell facilitates the expression of viral antigens on the surface of infected cells, drawing the attention of immune cells called cytotoxic T cells. These immune cells zero in on and destroy the infected cells, together with the invading virus inside them. In addition to analyzing gene expression in COVID-19 patients, the research team also infected human cell lines with the SARS-CoV-2 virus to validate their findings.

The results showed that a protein from the SARS-CoV-2 virus, called ORF 6, suppresses a host cell protein, called NLRC5, responsible for activating the MHC class I pathway.

The study showed this happens in two ways. ORF6 hampers cell signaling, which turns off the expression of NLRC5. ORF6 also blocks the function of NLRC5.

Other infectious viruses, including HIV and MERS, are known to also target the MHC class I pathway. Researchers believed that SARS-CoV-2 probably did as well, but this study is the first to unravel the mechanism.

"Without the activation of the MHC class I pathway, viruses in the infected cells are essentially hidden from the immune system. That helps to explain why SARS-CoV-2 virus persists in the body and why it keeps infecting others, leading to the pandemic.

Further research could help find and test drugs that block the activity of the ORF6 viral protein, to restore host cell ability to activate the major histocompatibility complex. If successful, such drugs could encourage the host immune system to clear the virus itself, effectively boosting immune responses.

Ji-Seung Yoo et al, SARS-CoV-2 inhibits induction of the MHC class I pathway by targeting the STAT1-IRF1-NLRC5 axis, Nature Communications (2021). DOI: 10.1038/s41467-021-26910-8

https://medicalxpress.com/news/2021-12-sars-cov-evades-immune.html?...

Comment by Dr. Krishna Kumari Challa on December 7, 2021 at 10:34am

In their scientific publication, the researchers list the possible explanations for the lack of dark matter one by one. For example, AGC 114905 could have been stripped of dark matter by large nearby galaxies. Mancera Piña: "But there are none. And in the most reputed galaxy formation framework, the so called cold dark matter model, we would have to introduce extreme parameter values that are far beyond the usual range. Also with modified Newtonian dynamics, an alternative theory to cold dark matter, we cannot reproduce the motions of the gas within the galaxy."

According to the researchers, there is one more assumption that could change their conclusions. That is the estimated angle at which they think they are observing the galaxy. "But that angle has to deviate very much from our estimate before there is room for dark matter again," says co-author Tom Oosterloo (ASTRON).

Meanwhile, the researchers are examining a second ultra-diffuse dwarf galaxy in detail. If again observe no trace of dark matter in that galaxy, it will make the case for dark matter poor galaxies even stronger.

The research of Mancera Piña and colleagues is not an isolated case. Earlier, for example, the Dutch American Pieter van Dokkum (Yale University, U.S.) discovered a galaxy with hardly any dark matter. The techniques and measurements of Mancera Piña and colleagues are more robust.

No need for dark matter: resolved kinematics of the ultra-diffuse galaxy AGC 114905 arXiv:2112.00017 [astro-ph.GA] arxiv.org/abs/2112.00017 . Accepted for publication in Monthly Notices of the Royal Astronomical Society.

https://phys.org/news/2021-12-evidence-emerges-dark-matter-free-gal...

Part 2

**

Comment by Dr. Krishna Kumari Challa on December 7, 2021 at 10:33am

Evidence emerges for dark-matter free galaxies

An international team of astronomers led by researchers from the Netherlands has found no trace of dark matter in the galaxy AGC 114905, despite taking detailed measurements over a course of forty hours with state-of-the-art telescopes. They will present their findings in Monthly Notices of the Royal Astronomical Society.

discovered six galaxies with little to no dark matter, they were told "measure again, you'll see that there will be dark matter around your galaxy". However, after forty hours of detailed observations using the Very Large Array (VLA) in New Mexico (United States), the evidence for a dark matter-free galaxy only became stronger.

The galaxy in question, AGC 114905, is about 250 million light-years away. It is classified as an ultra-diffuse dwarf galaxy, with the name 'dwarf galaxy' referring to its luminosity and not to its size. The galaxy is about the size of our own Milky Way but contains a thousand times fewer stars. The prevailing idea is that all galaxies, and certainly ultra-diffuse dwarf galaxies, can only exist if they are held together by dark matter.

The researchers collected data on the rotation of gas in AGC 114905 for 40 hours between July and October 2020 using the VLA telescope. Subsequently, they made a graph showing the distance of the gas from the center of the galaxy on the x-axis and the rotation speed of the gas on the y-axis. This is a standard way to reveal the presence of dark matter. The graph shows that the motions of the gas in AGC 114905 can be completely explained by just normal matter.

Part1

• ‹ Previous
• 1
• …
• 545
• 546
• 547
• 548
• 549
• …
• 1082
• Next ›
• Page