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Comment by Dr. Krishna Kumari Challa on October 28, 2021 at 8:33am

Researchers create mirror-image peptides that can neutralize SARS-CoV-2

Researchers at the University of Toronto have created chemical compounds that can neutralize SARS-CoV-2 and several of its variants.

In a recent paper published in the Journal of Medicinal Chemistry, the researchers report the creation of D-peptides that neutralize the virus and stop infection of cultured human cells.

Known as mirror-image peptides, the compounds have chemical properties that make them suitable for the development of low-cost antiviral therapeutics.

A big advantage of mirror-image peptides is their long stability and that they are relatively cheap to produce.

Peptides are similar to proteins in that they are composed of the same amino-acids building blocks. But they are smaller than protein molecules. They can be designed to bind virtually any molecular target and with a greater specificity than small-molecule drugs, reducing the risk of side effects. In this way, peptides are similar to antibodies but are at least 100 times cheaper to produce thanks to their small size. The combination of low cost and easy scaling of manufacturing makes peptides attractive, particularly for low-income countries.

But there's a caveat. In the body, peptides are rapidly degraded by the enzymes that have evolved to stamp out harmful versions produced by bacteria and other pathogens. But science has found a solution in mirror-image peptides that are resistant to degradation.

For reasons that remain unclear, all naturally occurring amino acids exist in a left-handed configuration, as defined by the direction in which they rotate. Consequently, all proteins and peptides are also left-handed—and known as L-peptides. These mirror-image molecules are manufactured from synthetic D-amino acids strung together in the same way as their left-handed counterparts.  They can be engineered to bind the same targets with undiminished specificity. The main difference is that their unusual geometry makes them resistant to enzymes in the bloodstream that break down normal L-peptides. 

Pedro A. Valiente et al, Computational Design of Potent D-Peptide Inhibitors of SARS-CoV-2, Journal of Medicinal Chemistry (2021). DOI: 10.1021/acs.jmedchem.1c00655

https://phys.org/news/2021-10-mirror-image-peptides-neutralize-sars...

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Comment by Dr. Krishna Kumari Challa on October 28, 2021 at 8:22am

Study confirms mistaken identity may explain why sharks bite humans

World-first research testing a simulated 'shark vision' model on swimming patterns of humans, seals and sea-lions, confirms theories that when great white sharks bite humans, it may be a case of mistaken identity.

Great white sharks are also called white sharks—and together with bull and tiger sharks, they account for by far the most bites on humans.

Researchers found that surfers, swimmers and pinnipeds (seals and sea-lions) on the surface of the ocean will look the same to a white shark looking up from below, because these sharks can't see fine details or colours.

Sharks use a range of sensory cues to distinguish between different objects and zero in on their food, and these differ in sensitivity between shark species. White sharks are highly visual—and juveniles are more dangerous to humans than are older, larger white sharks which have better vision.

When white sharks reach around 2.5 meters in length, their jaws begin to harden so they can take on bigger prey like seals. They need to develop a search image for these prey items and combine that with other sensory information; it's a learning process that could be prone to mistakes. Understanding why shark bites occur can help us find ways to prevent them, while keeping both humans and sharks safer.

 Laura A. Ryan et al, A shark's eye view: testing the 'mistaken identity theory' behind shark bites on humans, Journal of The Royal Society Interface (2021). DOI: 10.1098/rsif.2021.0533

https://phys.org/news/2021-10-mistaken-identity-sharks-humans.html?...

Comment by Dr. Krishna Kumari Challa on October 28, 2021 at 7:54am

Atoms .... see them!

Comment by Dr. Krishna Kumari Challa on October 28, 2021 at 6:56am

Comment by Dr. Krishna Kumari Challa on October 27, 2021 at 9:59am

 quantum sensing can work without a high-powered vacuum system. This shrinks the package to a practical size without sacrificing reliability.

Instead of a powered vacuum pump, which whisks away molecules that leak in and wreck measurements, a pair of devices called getters use chemical reactions to bind intruders. The getters are each about the size of a pencil eraser so they can be tucked inside two narrow tubes sticking out of the titanium package. They also work without a power source.

To further keep out contaminants, Schwindt partnered with Sandia materials scientists to build the chamber out of titanium and sapphire. These materials are especially good at blocking out gasses like helium, which can squeeze through stainless steel and Pyrex glass. Funding was provided by Sandia’s Laboratory Directed Research and Development program.

Construction took sophisticated fabrication techniques that Sandia has honed to bond advanced materials for nuclear weapons components. And like a nuclear weapon, the titanium chamber must work reliably for years.

The Sandia team is continuing to monitor the device. Their goal is to keep it sealed and operational for five years, an important milestone toward showing the technology is ready to be fielded. In the meantime, they’re exploring ways to streamline manufacturing.

https://www.eurekalert.org/news-releases/932743

part2

Comment by Dr. Krishna Kumari Challa on October 27, 2021 at 9:59am

This device could usher in GPS-free navigation

A new era of navigation.

For over a year, the avocado-sized vacuum chamber has contained a cloud of atoms at the right conditions for precise navigational measurements. It is the first device that is small, energy-efficient and reliable enough to potentially move quantum sensors — sensors that use quantum mechanics to outperform conventional technologies — from the lab into commercial use, said Sandia National Laboratories scientist Peter Schwindt.

Sandia developed the chamber as a core technology for future navigation systems that don’t rely on GPS satellite.

Countless devices around the world use GPS for wayfinding. It’s possible because atomic clocks, which are known for extremely accurate timekeeping, hold the network of satellites perfectly in sync.

But GPS signals can be jammed or spoofed, potentially disabling navigation systems on commercial and military vehicles alike, Schwindt said.

So instead of relying on satellites,  future vehicles might keep track of their own position. They could do that with on-board devices as accurate as atomic clocks, but that measure acceleration and rotation by shining lasers into small clouds of rubidium gas like this one.

Atomic accelerometers and gyroscopes already exist, but they’re too bulky and power-hungry to use in an airplane’s navigation system. That’s because they need a large vacuum system to work, one that needs thousands of volts of electricity.

“Quantum sensors are a growing field, and there are lots of applications you can demonstrate in the lab. But when you move it into the real world there are lots of problems you have to solve. Two are making the sensor compact and rugged. The physics takes place all in a cubic centimeter (0.06 cubic inches) of volume, so anything larger than that is wasted space.”

part1

Comment by Dr. Krishna Kumari Challa on October 27, 2021 at 9:53am

Underwater Drone Flies AND Swims

Comment by Dr. Krishna Kumari Challa on October 27, 2021 at 9:22am

 Lack of sleep affects your walk, new study finds

Good sleep can be hard to come by. But a new study finds that if you can make up for lost sleep, even for just a few weekend hours, the extra zzz's could help reduce fatigue-induced clumsiness, at least in how you walk.

There's plenty of evidence to show sleep, and how much we get of it, can affect how well we do on cognitive tasks such as solving a math problem, holding a conversation, or even reading this article. Less explored is the question of whether sleep influences the way we walk or carry out other activities that are assumed to be less mentally taxing.

The new study, by researchers at MIT and the University of São Paulo in Brazil, reports that walking—and specifically, how well we can control our stride, or gait—can indeed be affected by lack of sleep.

In experiments with student volunteers, the team found that overall, the less sleep students got, the less control they had when walking during a tread-mill test. For students who pulled an all-nighter before the test, this gait control plummeted even further.

Interestingly, for those who didn't stay up all night before the test, but who generally had less-than-ideal sleep during the week, those who slept in on weekends performed better than those who didn't.

Sleep deprivation affects gait control, Scientific Reports (2021). DOI: 10.1038/s41598-021-00705-9

https://medicalxpress.com/news/2021-10-feet-lack-affects.html?utm_s...

Comment by Dr. Krishna Kumari Challa on October 27, 2021 at 9:05am

'Nanozyme' therapy prevents harmful dental plaque build-up

A growing body of evidence points to a link between iron-deficiency anemia and severe tooth decay. Whether the connection is correlative or causative is unknown, though both conditions are associated with poor diets and are more common in people living in impoverished environments and with underlying medical conditions.

Now, new research suggests that an FDA-approved therapy for iron-deficiency anemia also holds promise for treating, preventing, and even diagnosing dental decay. The therapeutic, a combination of an iron-oxide nanoparticle-containing solution called ferumoxytol and hydrogen peroxide, was applied to real tooth enamel placed in a denture-like appliance and worn by the study subjects.

The study, published in the journal Nano Letters, found that a twice daily application of ferumoxytol, which activated hydrogen peroxide contained in a follow-up rinse, significantly reduced the buildup of harmful dental plaque and had a targeted effect on the bacteria largely responsible for tooth decay. These types of nanoparticles with enzyme-like properties are sometimes known as "nanozymes" and are increasingly being explored for their potential in biomedical and environmental applications.

Researchers found that this approach is both precise and effective. It disrupts biofilms, particularly those formed by Streptococcus mutans, which cause caries, and it also reduced the extent of enamel decay. 

Yuan Liu et al, Ferumoxytol Nanoparticles Target Biofilms Causing Tooth Decay in the Human Mouth, Nano Letters (2021). DOI: 10.1021/acs.nanolett.1c02702

https://phys.org/news/2021-10-nanozyme-therapy-dental-plaque-build-...

Comment by Dr. Krishna Kumari Challa on October 26, 2021 at 11:57am

Found: an Unknown 'Ghost' Ancestor in The Human Genome

A teenage girl from over 50,000 years ago of such strange uniqueness she looked to be a 'hybrid' ancestor to modern humans that scientists had never seen before.

Only recently, researchers have uncovered evidence she wasn't alone. In a 2019 study analysing the complex mess of humanity's prehistory, scientists used artificial intelligence (AI) to identify an unknown human ancestor species that modern humans encountered – and shared dalliances with – on the long trek out of Africa millennia ago.

About 80,000 years ago, the so-called Out of Africa occurred, when part of the human population, which already consisted of modern humans, abandoned the African continent and migrated to other continents, giving rise to all the current populations.

As modern humans forged this path into the landmass of Eurasia, they forged some other things too – breeding with ancient and extinct hominids from other species.

Up until recently, these occasional sexual partners were thought to include Neanderthals and Denisovans, the latter of which were unknown until 2010.

But in this study, a third ex from long ago was isolated in Eurasian DNA, thanks to deep learning algorithms sifting through a complex mass of ancient and modern human genetic code. 

Using a statistical technique called Bayesian inference, the researchers found evidence of what they call a "third introgression" – a 'ghost' archaic population that modern humans interbred with during the African exodus.

This population is either related to the Neanderthal-Denisova clade or diverged early from the Denisova lineage.

 In 2018, another team of researchers identified evidence of what they called a "definite third interbreeding event" alongside Denisovans and Neanderthals, and a pair of papers published in early 2019 traced the timeline of how those extinct species intersected and interbred in clearer detail than ever before.

There's a lot more research to be done here yet. Applying this kind of AI analysis is a decidedly new technique in the field of human ancestry, and the known fossil evidence we're dealing with is amazingly scant.

But according to the research, what the team has found explains not only a long-forgotten process of introgression – it's a dalliance that, in its own way, informs part of who we are today. If you subtract the Neanderthal and Denisovan parts, there is still something in the genome that is highly divergent.

https://www.nature.com/articles/s41467-018-08089-7

https://www.sciencealert.com/artificial-intelligence-finds-an-unkno...

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