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Comment by Dr. Krishna Kumari Challa on January 26, 2024 at 8:49am

This "smart" material, called FG phase, is jelly-like and impenetrable for most macromolecules. It fills and blocks the nuclear pore channel. Importins and exportins, however, can pass through because their surfaces are optimized for sliding through an FG phase.

The cell's border control in the FG phase happens extremely fast—within milliseconds. Likewise, its transport capacity is enormous: A single nuclear pore can transfer up to 1,000 transporters per second through its channel. Even with such a high traffic density, the barrier of nuclear pores remains intact and keeps suppressing unwanted border crossings. HIV, however, subverts this control.
HIV packages its genome into a capsid. Recent evidence suggests that the genome stays inside the capsid until it reaches the nucleus, and thus also when passing the nuclear pore. But there is a size problem.
The central pore channel is 40 to 60 nanometers wide. The capsid has a width of about 60 nanometers and could just squeeze through the pore.

However, a normal cellular cargo would still be covered by a transporter layer that adds at least another ten nanometers. The HIV capsid would then be 70 nanometers wide—too big for a nuclear pore. Nevertheless, cryo-electron tomography has shown that the HIV capsid gets into the nuclear pore. But how this happens has been so far a mystery in HIV infection.

 Liran Fu et al, HIV-1 capsids enter the FG phase of nuclear pores like a transport receptor, Nature (2024). DOI: 10.1038/s41586-023-06966-w

Part 2

Comment by Dr. Krishna Kumari Challa on January 26, 2024 at 8:47am

How HIV smuggles its genetic material into the cell nucleus

Each year, about 1 million individuals worldwide become infected with HIV, the virus that causes AIDS. To replicate and spread the infection, the virus must smuggle its genetic material into the cell nucleus and integrate it into a chromosome.

Researchers have now discovered that its capsid has evolved into a molecular transporter. As such, it can directly breach a crucial barrier, which normally protects the cell nucleus against viral invaders. This way of smuggling keeps the viral genome invisible to anti-viral sensors in the cytoplasm. Their study is published in Nature. 

Forty years after the human immunodeficiency virus (HIV) was discovered as the cause of AIDS, we have therapies that effectively keep the pathogen under control, but there is still no cure. The virus infects certain immune cells and hijacks their genetic program in order to multiply and replicate its own genetic material. The infected cells then produce the next generation of viruses until they are finally destroyed. The immunodeficiency symptoms of AIDS result from the massive loss of immune cells that normally fight viruses and other pathogens.
To use the host cell's resources, HIV must smuggle its genetic material through cellular defense lines into the cell nucleus. The nucleus, however, is closely guarded. Its nuclear envelope prevents unwanted proteins or harmful viruses from entering the nucleus and macromolecules from an uncontrolled escape. Yet, selected proteins can pass because the barrier is not hermetically sealed.

Thousands of tiny nuclear pores in the nuclear envelope provide a passageway. They control these transport processes with the help of importins and exportins—molecular transporters that capture cargoes with valid molecular "passcodes" and deliver them through the nuclear pore channel. A "smart" material turns these pores into one of nature's most efficient sorting and transport machines.

Part 1

Comment by Dr. Krishna Kumari Challa on January 26, 2024 at 8:32am

Scientists discover the moon is shrinking, causing landslides and instability in lunar south pole

Earth's moon shrank more than 150 feet in circumference as its core gradually cooled over the last few hundred million years. In much the same way a grape wrinkles when it shrinks down to a raisin, the moon also develops creases as it shrinks. But unlike the flexible skin on a grape, the moon's surface is brittle, causing faults to form where sections of crust push against one another.

A team of scientists discovered evidence that this continuing shrinkage of the moon led to notable surface warping in its south polar region—including areas that NASA proposed for crewed Artemis III landings. Because fault formation caused by the moon's shrinking is often accompanied by seismic activity like moonquakes, locations near or within such fault zones could pose dangers to future human exploration efforts.

In a paper published in The Planetary Science Journal, the team linked a group of faults located in the moon's south polar region to one of the most powerful moonquakes recorded by Apollo seismometers over 50 years ago. Using models to simulate the stability of surface slopes in the region, the team found that some areas were particularly vulnerable to landslides from seismic shaking.

Shallow moonquakes occur near the surface of the moon, just a hundred or so miles deep into the crust. Similar to earthquakes, shallow moonquakes are caused by faults in the moon's interior and can be strong enough to damage buildings, equipment and other human-made structures.

But unlike earthquakes, which tend to last only a few seconds or minutes, shallow moonquakes can last for hours and even a whole afternoon.

Watters et al, Tectonics and Seismicity of the Lunar South Polar Region, The Planetary Science Journal (2024). DOI: 10.3847/PSJ/ad1332

Comment by Dr. Krishna Kumari Challa on January 26, 2024 at 8:26am

For this run the energy in the collision of the two protons was 13 trillion electron-volts, just below the machine's current maximum, which in more relatable units is 2.1 microjoules. That's about the kinetic energy of the average mosquito, or a grain of salt, traveling one meter per second.

Theory predicts that about 15 times per 10,000 decays, the Higgs boson should decay into a Z boson and a photon, the rarest decay in the Standard Model. It does so by first producing a pair of top quarks, or a pair of W bosons, which themselves then decay into the Z and photon.

The Atlas/CMS collaboration, work from more than 9,000 scientists, found a "branching ratio," or fraction of decays of 34 times per 10,000 decays, plus or minus 11 per 10,000—2.2 times the theoretical value.

The measured fraction is too large—3.4 standard deviations above the theoretical value, a number still too small to rule out a statistical fluke. Still, the relatively large difference hints at the possibility of a meaningful discrepancy from theory that could be due to physics beyond the Standard Model—new particles that are the intermediaries other than the top quark and W bosons.
One possibility for physics beyond the Standard Model is supersymmetry, the theory that posits a symmetry—a relationship—between particles of a half-spin, called fermions, and integer spin, called bosons, with every known particle having a partner with a spin differing by a half-integer.

Many theoretical physicists have long been advocates of supersymmetry as it would solve many conundrums that plague the Standard Model, such as the large difference (1024) between the strengths of the weak force and gravity, or why the mass of the Higgs boson, about 125 gigaelectron-volts (GeV), is so much less than the grand unification energy scale of about 1016 GeV.

G. Aad et al, Evidence for the Higgs Boson Decay to a Z Boson and a Photon at the LHC, Physical Review Letters (2024). DOI: 10.1103/PhysRevLett.132.021803

Part 2

Comment by Dr. Krishna Kumari Challa on January 26, 2024 at 8:25am

Rare decay of the Higgs boson may point to physics beyond the Standard Model

Particle physicists have detected a novel decay of the Higgs boson for the first time, revealing a slight discrepancy in the predictions of the Standard Model and perhaps pointing to new physics beyond it. 

The Higgs boson, predicted theoretically since the 1960s, was finally detected in 2012 at the CERN laboratory in Europe. As a quantum field it permeates all of space, through which other particles move, acquiring mass via their interaction with the Higgs field that can be roughly envisioned as a kind of resistance to their motion. Many properties of the Higgs boson, including how it interacts with other particle and their associated fields, have already been measured to be consistent with predictions of the Standard Model.

But one Higgs decay mode that had yet to be investigated was a theoretical prediction that a Higgs boson would occasionally decay and produce a photon, the quantum of light, and a Z boson, which is an uncharged particle that together with the two W bosons conveys the weak force.

Scientists from the ATLAS and CMS collaborations at CERN used data from proton-proton collisions taken from Run 2 from 2015 to 2018 to search for this particular Z+photon Higgs decay. The Large Hadron Collider (LHC) at CERN is the high-energy particle accelerator near Geneva, Switzerland that circulates protons in opposite directions while causing them to collide at specific detector points, millions of times per second.
Part 1

Comment by Dr. Krishna Kumari Challa on January 25, 2024 at 12:29pm

Science can only ascertain what is, but not what should be, and outside its domain value judgments of all kinds remain 

Comment by Dr. Krishna Kumari Challa on January 25, 2024 at 12:07pm

Einstein stood on the shoulders of giants In The Einsteinian Revolution, two eminent experts on Einstein’s life and his theory of relativity — physicist Hanoch Gutfreund and historian of science Jürgen Renn — offer an original and penetrating analysis of Einstein’s unparalleled contributions. “The book is much more than another product of the Einstein industry,” writes historian Helge Kragh. “By setting his work in the long arc of the evolution of scientific knowledge, Gutfreund and Renn dispel the popular myth of Einstein as an unconventional scientific genius who single-handedly created modern physics from scratch — and by pure thought alone.” Nature

Comment by Dr. Krishna Kumari Challa on January 25, 2024 at 12:06pm

How chronic stress harms the gut

Researchers have revealed one of the mind-body connections that links stress to gastrointestinal flare-ups. In mice, Lactobacillus bacteria  which naturally occur in the gut and proliferate under stressful conditions produce a chemical that disrupts teh production of  intestine-protecting cells. The team also found elevated levels of Lactobacillus, and the harmful chemical, in the faeces of people with depression. When we suffer from stress, our gut microbiome is also suffering from stress. 

Nature
 Cell Metabolism 

Comment by Dr. Krishna Kumari Challa on January 25, 2024 at 11:47am

Why coffee beans taste different

Differences in the flavours of Arabica coffee varieties aren’t because of variations in individual genes. Rather, they seem to be mainly the result of wholesale swapping, deletion and rearrangement.... The most complete sequencing yet of Coffea arabica’s genome reveals that the levels of single-‘letter’ variations in the plant’s DNA “are anywhere from 10 to 100 times lower than any other species”, says plant geneticist and study co-author Michele Morgante.

Nature
 Nature Communications paper

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Comment by Dr. Krishna Kumari Challa on January 25, 2024 at 11:43am

Researchers observe tiny pseudoscorpion riding on a scorpion

Researchers recently  documented the first observation of phoresy involving a myrmecophile pseudo-scorpion on a myrmecophile scorpion.

Phoresy, a well-established phenomenon among pseudoscorpions, involves their attachment to hosts for dispersal into new environments. Documented instances of phoresy include pseudoscorpions attaching themselves to various hosts, ranging from mammals and birds to different insect orders and even other arachnids.

The study focused on pseudoscorpions belonging to an endemic Withiidae species, Nannowithius wahrmani, observed clinging onto the endemic scorpion species Birulatus israelensis in Israel. The research paper, titled "Hitching a ride on a scorpion: the first record of phoresy of a myrmecophile pseudoscorpion on a myrmecophile scorpion," is published in Arachnologische Mitteilungen: Arachnology Letters.

Sharon Warburg et al, Hitching a ride on a scorpion: the first record of phoresy of a myrmecophile pseudoscorpion on a myrmecophile scorpion, Arachnologische Mitteilungen: Arachnology Letters (2024). DOI: 10.30963/aramit6605

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