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Comment by Dr. Krishna Kumari Challa on July 27, 2021 at 11:03am

Through the thin-film glass, researchers spot a new liquid phase

Research published in the Proceedings of the National Academy of Sciences describes a new type of liquid in thin films, which forms a high-density glass. Results generated in this study, conducted by researchers in Penn's Department of Chemistry, demonstrate how these glasses and other similar materials can be fabricated to be denser and more stable, providing a framework for developing new applications and devices through better design.

To make better glasses, researchers have used vapor deposition instead of cooling a liquid to produce a glass. In vapor deposition, a material is changed from a gas into a solid directly. While this method has allowed researchers to create denser types of bulk glasses, it was initially thought that thin glass films made using this method would still have the same liquid-like properties that would lead to degradation and instability.

After running all of the control experiments needed, the researchers were surprised to find that when using vapor deposition, they could access a different type of liquid, with a phase transition to the typical bulk liquid upon heating. A phase transition is when a material changes from from one state (gas, liquid, or solid) into another. "The two liquids have distinct structures, akin to graphene and diamond which are both solids made of carbon but exist in very different solid forms.

There are a lot of interesting properties that came out of nowhere, and nobody had thought that in thin films you would be able to see these phases. It's a new type of material.

Yi Jin el al., "Glasses denser than the supercooled liquid," PNAS (2021). www.pnas.org/cgi/doi/10.1073/pnas.2100738118

https://phys.org/news/2021-07-thin-film-glass-liquid-phase.html?utm...

Comment by Dr. Krishna Kumari Challa on July 26, 2021 at 10:14am

Surfing science: Dependent on weather, defined by the ocean

Serious wave chasers are by default atmospheric science junkies because there are few, if any, sports that are both dependent on an uncontrollable variable—the weather—and defined by a literal uneven playing field—the ocean.

Waves are created by the way the swells interact with the bottom contours of the ocean, called the break. Beach breaks—like the Olympic site at Tsurigasaki beach—happen because of sandbars, which can shift over time or due to storms.

Competitive surfing in a nutshell is about deciding which wave to take and what move or moves make the best use of what the ocean delivers. Surfers have to remain prepared and continuously observe the waves for their best guess of what wave they will get to ride.

https://phys.org/news/2021-07-surfing-science-weather-ocean.html?ut...

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Comment by Dr. Krishna Kumari Challa on July 26, 2021 at 10:00am

15,000-year-old viruses discovered in Tibetan glacier ice

Scientists who study glacier ice have found viruses nearly 15,000 years old in two ice samples taken from the Tibetan Plateau in China. Most of those viruses, which survived because they had remained frozen, are unlike any viruses that have been cataloged to date.

The findings, published today in the journal Microbiome, could help scientists understand how viruses have evolved over centuries. For this study, the scientists also created a new, ultra-clean method of analyzing microbes and viruses in ice without contaminating it.

The researchers analyzed ice cores taken in 2015 from the Guliya ice cap in western China. The cores are collected at high altitudes—the summit of Guliya, where this ice originated, is 22,000 feet above sea level. The ice cores contain layers of ice that accumulate year after year, trapping whatever was in the atmosphere around them at the time each layer froze. Those layers create a timeline of sorts, which scientists have used to understand more about climate change, microbes, viruses and gasses throughout history.

Researchers determined that the ice was nearly 15,000 years old using a combination of traditional and new, novel techniques to date this ice core.

When they analyzed the ice, they found genetic codes for 33 viruses. Four of those viruses have already been identified by the scientific community. But at least 28 of them are novel. About half of them seemed to have survived at the time they were frozen not in spite of the ice, but because of it.

These viruses have signatures of genes that help them infect cells in cold environments—just surreal genetic signatures for how a virus is able to survive in extreme conditions.

Zhi-Ping Zhong et al, Glacier ice archives nearly 15,000-year-old microbes and phages, Microbiome (2021). DOI: 10.1186/s40168-021-01106-w

https://phys.org/news/2021-07-year-old-viruses-tibetan-glacier-ice....

Comment by Dr. Krishna Kumari Challa on July 25, 2021 at 10:11am

‘Ancient RNA virus epidemics occurred frequently during human evolution’

• Genome adaptations may offer insight into a viral epidemic as far back as 25,000 years.
• Several lines of evidence point to a coronavirus or similar virus that emerged among the ancestors of East Asian people.
• Identifying ancient viral activity may uncover the potential of evolutionary genomic methods to predict and combat future pandemics.

https://www.sciencedirect.com/science/article/pii/S0960982221007946#!

https://www.medicalnewstoday.com/articles/ancient-rna-virus-epidemi...

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Comment by Dr. Krishna Kumari Challa on July 25, 2021 at 10:08am

How Carbon Capture Works

Comment by Dr. Krishna Kumari Challa on July 25, 2021 at 10:05am

Scientists reverse age-related memory loss in mice

In a study published in Molecular Psychiatry,  a research team show that changes in the extracellular matrix of the brain scaffolding around nerve cells  lead to loss of memory with ageing, but that it is possible to reverse these using genetic treatments. Recent evidence has emerged of the role of perineuronal nets (PNNs) in neuroplasticity  the ability of the brain to learn and adapt  and to make memories. PNNs are cartilage-like structures that mostly surround inhibitory neurons in the brain. Their main function is to control the level of plasticity in the brain. They appear at around five years old in humans, and turn off the period of enhanced plasticity during which the connections in the brain are optimised. Then, plasticity is partially turned off, making the brain more efficient but less plastic. PNNs contain compounds known as chondroitin sulphates. Some of these, such as chondroitin 4-sulphate, inhibit the action of the networks, inhibiting neuroplasticity; others, such as chondroitin 6-sulphate, promote neuroplasticity. As we age, the balance of these compounds changes, and as levels of chondroitin 6-sulphate decrease, so our ability to learn and form new memories changes, leading to age-related memory decline.

They investigated whether manipulating the chondroitin sulphate composition of the PNNs might restore neuroplasticity and alleviate age-related memory deficits.

To do this, the team looked at 20-month old mice – considered very old – and using a suite of tests showed that the mice exhibited deficits in their memory compared to six-month old mice.

For example, one test involved seeing whether mice recognised an object. The mouse was placed at the start of a Y-shaped maze and left to explore two identical objects at the end of the two arms. After a short while, the mouse was once again placed in the maze, but this time one arm contained a new object, while the other contained a copy of the repeated object. The researchers measured the amount of time the mouse spent exploring each object to see whether it had remembered the object from the previous task. The older mice were much less likely to remember the object.

The team treated the ageing mice using a ‘viral vector’, a virus capable of reconstituting the amount of 6-sulphate chondroitin sulphates to the PNNs and found that this completely restored memory in the older mice, to a level similar to that seen in the younger mice.

1. Sujeong Yang, Sylvain Gigout, Angelo Molinaro, Yuko Naito-Matsui, Sam Hilton, Simona Foscarin, Bart Nieuwenhuis, Chin Lik Tan, Joost Verhaagen, Tommaso Pizzorusso, Lisa M. Saksida, Timothy M. Bussey, Hiroshi Kitagawa, Jessica C. F. Kwok, James W. Fawcett. Chondroitin 6-sulphate is required for neuroplasticity and memory in ageing. Molecular Psychiatry, 2021; DOI: 10.1038/s41380-021-01208-9

Comment by Dr. Krishna Kumari Challa on July 25, 2021 at 9:56am

Cockatoos   have learned to open curb-side bins — and it has global significance

https://theconversation.com/clever-cockatoos-in-southern-sydney-hav...

Comment by Dr. Krishna Kumari Challa on July 24, 2021 at 8:10am

The science of underwater swimming: How staying submerged gives Olympians the winning edge

To win swimming gold in Tokyo, swimmers not only have to generate incredible power with their arms and legs to propel themselves through the water; they also have to overcome the relentless pull of the water's drag while doing so.

Without being able to don special low-drag suits or use technologies to help them fly over the water, how can swimmers make the effect of the water's drag as small as possible?

The best athletes in this year's Olympics will do it by swimming under, rather than on top of, the water—at least as far as the rules allow.

Water is much denser than air, so you might assume swimmers would benefit from using a technique that allows them to sit high in the water, with as much of their body out of the water as possible.

But there are two problems with this strategy.

First, it costs energy to produce the forces needed to lift the body, which would be better spent propelling the swimmer forwards towards the finishing wall.

Second, when we travel on the water's surface we waste energy making waves. During fast swimming, such as in the sprint freestyle events or during starts and turns (where speeds exceed 2 meters per second, or about 7 kilometers per hour), wave generation slows the swimmer down more than any other factor. Reducing wave formation is therefore vital to swimming success.

Waves are produced as the pressure exerted by the swimmer on the water forces the water upwards and out of their path. Other pressure changes around the swimmer's body also cause waves to form behind them, and sometimes to the side.

The energy required to generate waves comes from the swimmer themselves, so a lot of the power generated by the swimmer's muscles is used in wave generation rather than moving the swimmer forwards.

But waves aren't formed when we (or fish, dolphins or whales) swim under the water, because waves only form when an object (like us) moves at the boundary between two fluids of different densities, such as water and air during swimming. And this fact hints at an intriguing solution to the drag issue.

Here, the swimmer propels themselves underwater by undulating the lower body in a wave-like manner while maintaining a rigid and streamlined upper body position with arms stretched overhead.

The amplitude of the lower body undulation increases from the hips to the feet so the "wave" produced by the body is much greater down towards the feet, creating a whip-like effect. This pushes water rapidly backwards, propelling the swimmer forwards according to Newton's law of action and reaction.

Although some aspects of underwater swimming is banned, the benefits of improving the underwater undulation technique are so great that swimmers still spend hours each week in training improving this part of the race.

https://theconversation.com/the-science-of-underwater-swimming-how-...

Comment by Dr. Krishna Kumari Challa on July 23, 2021 at 10:11am

Why delta variant is highly transmissible 

In a preprint posted 12 July¹, the researchers report that virus was first detectable in people with the Delta variant four days after exposure,compared with an average of six days among people with the original strain, suggesting that Delta replicates much faster. Individuals infected with Delta also had viral loads up to 1,260 times higher than those in people infected with the original strain.

The combination of a high number of viruses and a short incubation period makes sense as an explanation for Delta’s heightened transmissibility.

The sheer amount of virus in the respiratory tract means that superspreading events are likely to infect even more people, and that people might begin spreading the virus earlier after they become infected.

And the short incubation makes contact tracing more difficult in some countries.

Putting it all together, Delta’s really difficult to stop.

The highly contagious Delta variant of Covid-19 is expected to become the dominant strain of the virus over the coming months, according to the World Health Organization.

https://www.medrxiv.org/content/10.1101/2021.07.07.21260122v1

https://www.nature.com/articles/d41586-021-01986-w?utm_source=Natur...

Comment by Dr. Krishna Kumari Challa on July 23, 2021 at 9:28am

How newborn mammals dream the world they're entering

As a newborn mammal opens its eyes for the first time, it can already make visual sense of the world around it. But how does this happen before they have experienced sight?

A new  study suggests that, in a sense, mammals dream about the world they are about to experience before they are even born.

Scientists describe the process as waves of activity that emanate from the neonatal retina in mice before their eyes ever open.

This activity disappears soon after birth and is replaced by a more mature network of neural transmissions of visual stimuli to the brain, where information is further encoded and stored.

But how do the circuits form that allow us to perceive motion and navigate the world? It turns out we are born capable of many of these behaviors, at least in rudimentary form.

Scientists explored the origins of these waves of activity. Imaging the brains of mice soon after birth but before their eyes opened, the Yale team found that these retinal waves flow in a pattern that mimics the activity that would occur if the animal were moving forward through the environment.

This early dream-like activity makes evolutionary sense because it allows a mouse to anticipate what it will experience after opening its eyes, and be prepared to respond immediately to environmental threats.

They also investigated the cells and circuits responsible for propagating the retinal waves that mimic forward motion in neonatal mice. They found that blocking the function of starburst amacrine cells, which are cells in the retina that release neurotransmitters, prevents the waves from flowing in the direction that mimics forward motion. This in turn impairs the development of the mouse's ability to respond to visual motion after birth.

Intriguingly, within the adult retina of the mouse these same cells play a crucial role in a more sophisticated motion detection circuit that allows them to respond to environmental cues.

Mice, of course, differ from humans in their ability to quickly navigate their environment soon after birth. However, human babies are also able to immediately detect objects and identify motion, such as a finger moving across their field of vision, suggesting that their visual system was also primed before birth.

These brain circuits are self-organized at birth and some of the early teaching is already done. It's like dreaming about what you are going to see before you even open your eyes.

X. Ge el al., "Retinal waves prime visual motion detection by simulating future optic flow," Science (2021). science.sciencemag.org/cgi/doi … 1126/science.abd0830

https://phys.org/news/2021-07-eyes-wide-newborn-mammals-world.html?...

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