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Comment by Dr. Krishna Kumari Challa on July 12, 2021 at 8:25am

Comment by Dr. Krishna Kumari Challa on July 12, 2021 at 8:24am

Sulfhemoglobinemia

Comment by Dr. Krishna Kumari Challa on July 11, 2021 at 10:57am

Scientists Have Created a New Bendy And Flexible Form of Ice

Water ice isn't exactly known for its flexibility. In fact, it's quite the opposite: rigid and brittle, easily fracturing and snapping. It's why avalanches and sea ice fragmentation occur.

It's also why new research is so fascinating. Scientists have just grown microfibers of water ice that can bend in a loop – breaking the previous maximum strain by a significant percentage and opening up new opportunities for the exploration of ice physics.

Ice doesn't always behave the way we expect, and its elasticity – or rather, lack thereof – is a perfect example. Theoretically, it should have a maximum elastic strain of around 15 percent. In the real world, the maximum elastic strain ever measured was less than 0.3 percent. The reason for this discrepancy is that ice crystals have structural imperfections that drive up their brittleness.

So a team of researchers led by nanoscientist Peizhen Xu of Zhejiang University in China sought to create ice with as few structural imperfections as possible.

The experiment consisted of a tungsten needle in an ultracold chamber, sitting at around minus 50 degrees Celsius, much colder than has been previously attempted. Water vapor was released into the chamber, and an electric field was applied. This attracted water molecules to the tip of the needle, where they crystallized, forming a microfiber with a maximum width of around 10 micrometers,  smaller than the width of a human hair.

The next step was to lower the temperature to between minus 70 and minus150 degrees Celsius. Under these low temperatures, the researchers tried bending the ice fibers.

At minus 150 degrees Celsius, they found that a microfiber 4.4 micrometers across was able to bend into a nearly circular shape, with a radius of 20 micrometers. This suggests a maximum elastic strain of 10.9 percent – much closer to the theoretical limit than previous attempts.

Even better, when the researchers released the ice, it sprang back into its previous shape.

https://science.sciencemag.org/content/373/6551/187

https://www.sciencealert.com/scientists-have-created-a-new-bendy-an...

Comment by Dr. Krishna Kumari Challa on July 10, 2021 at 11:24am

Scientists reveal how cauliflowers develop their unique shape

 Have you ever wondered how a cauliflower grows into its strange shape? - The mystery of how this peculiar shaped vegetable forms has now been solved by a team of mathematicians and plant scientists.

Now a new study revealed that cauliflowers, and Romanescos in particular, are in fact buds that are designed to become flowers but which never reach their goal. The findings have been published in Science.

The research combines mathematical modelling and plant biology to show that instead of reaching flowering stage cauliflowers develop into stems, which in turn continue trying to produce flowers. The cauliflower is born from this chain reaction, resulting in a succession of stems upon stems.

This study shows that the brief incursion of buds into a flowering state profoundly affects their functioning and allows them, unlike normal stems, to grow without leaves and to multiply almost infinitely. The atypical shape of the Romanesco is explained by the fact that its stems produce buds more and more rapidly (whereas the production rate is constant in other cauliflowers). This acceleration gives each floret a pyramidal appearance, making the fractal aspect of the structure clear. The study highlights how the selection of mutations in plants during the process of domestication has changed their shape, sometimes drastically, into the fruits and vegetables on our shelves.

https://www.nottingham.ac.uk/news/scientists-reveal-how-cauliflower...

Although most plants present a geometric organisation in spirals along main and secondary axes (called "phyllotaxis"), cauliflowers present an unusual phyllotaxis with a multitude of spirals, nested over a wide range of scales. How such a fractal self-similar organization emerges from developmental mechanisms has, until now, remained elusive.

Combining experimental analyses in Arabidopsis thaliana cauliflower-like mutant with mathematical modelling, researchers found that curd self-similarity arises because growing plant tissues fail to form flowers but keep the “memory” of their transient passage in a floral state. Understanding this genetic mutation could help plant scientists optimise growth of related plants.

https://researchnews.cc/news/7684/Scientists-reveal-how-cauliflower...

Comment by Dr. Krishna Kumari Challa on July 9, 2021 at 12:04pm

Biological fireworks show 300 million years in the making

Five years ago, researchers  discovered that human eggs, when fertilized by sperm, release billions of zinc ions, dubbed "zinc sparks."

They now found out that these same sparks fly from highly specialized metal-loaded compartments at the egg surface when frog eggs are fertilized. This means that the early chemistry of conception has evolutionary roots going back at least 300 million years, to the last common ancestor between frogs and people.

And the research has implications beyond this shared biology and deep-rooted history. It could also help shape future findings about how metals impact the earliest moments in human development. This work may help inform our understanding of the interplay of dietary zinc status and human fertility.

They also discovered that fertilized frog eggs eject another metal, manganese, in addition to zinc. It appears these ejected manganese ions collide with sperm surrounding the fertilized egg and prevent them from entering.

These breakthroughs support an emerging picture that transition metals are used by cells to regulate some of the earliest decisions in the life of an organism.

John F. Seeler et al, Metal ion fluxes controlling amphibian fertilization, Nature Chemistry (2021). DOI: 10.1038/s41557-021-00705-2

https://phys.org/news/2021-07-biological-fireworks-million-years.ht...

Comment by Dr. Krishna Kumari Challa on July 9, 2021 at 11:58am

More cell phone data use is negatively affecting Wi-Fi performance, study finds

If service becomes slow when you're trying to send a quick email on your smartphone, you might scroll through your network options and discover how many Wi-Fi networks there are. In fact, this plethora of options is itself the problem. These networks are in competition with one another, limiting the speed at which each can operate.

Hidden-nodes in coexisting LAA & Wi-Fi: a measurement study of real deployments. arxiv.org/abs/2103.15591

Comment by Dr. Krishna Kumari Challa on July 9, 2021 at 11:11am

Stem cells can use same method as plants and insects to protect against viruses

Researchers at the Francis Crick Institute have found a vital mechanism, previously thought to have disappeared as mammals evolved, that helps protect mammalian stem cells from RNA viruses such as SARS-CoV-2 and Zika virus. The scientists suggest this could one day be exploited in the development of new antiviral treatments.

On infecting a host, a virus enters cells in order to replicate. For most cells in mammals the first line of protection are proteins, called interferons. Stem cells, however, lack the ability to trigger an interferon response and there has been uncertainty about how they protect themselves.

In their study, published in Science today the scientists analyzed genetic material from mouse stem cells and found it contains instructions to build a protein, named antiviral Dicer (aviD), which cuts up viral RNA and so prevents RNA viruses from replicating. This form of protection is called RNA interference, which is the method also used by cells in plants and invertebrates.

In laboratory experiments which exposed engineered human cells to SARS-CoV-2, the virus infected three times fewer stem cells when aviD was present in the cells compared to when the researchers removed this protein.

An isoform of Dicer protects mammalian stem cells against multiple RNA viruses" Science (2021). science.sciencemag.org/lookup/ … 1126/science.abg2264

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It's fascinating to learn how stem cells protect themselves against RNA viruses. The fact this protection is also what plants and invertebrates use suggests it might be something that goes far back in mammalian history, right up to when the evolutionary tree spilt. For some reason, while all mammalian cells possess the innate ability to trigger this process, it seems to only be relied upon by stem cells.

By learning more about this process, and uncovering the secrets of our immune system we are hoping to open up new possibilities for drug development as we strive to harness our body's natural ability to fight infection

The scientists also grew mini brain organoids from mouse embryonic stem cells and found that, when infected with Zika virus, the organoids with aviD grew more quickly and less viral material was produced than in organoids without this protein. Similarly, when organoids were infected with SARS-CoV-2, there were fewer infected stem cells in the organoids with aviD.

https://phys.org/news/2021-07-stem-cells-method-insects-viruses.htm...

Comment by Dr. Krishna Kumari Challa on July 9, 2021 at 10:46am

Climate changed the size of our bodies 

An interdisciplinary team of researchers has gathered measurements of body and brain size for over 300 fossils from the genus Homo found across the globe. By combining this data with a reconstruction of the world's regional climates over the last million years, they have pinpointed the specific climate experienced by each fossil when it was a living human.

The study reveals that the average body size of humans has fluctuated significantly over the last million years, with larger bodies evolving in colder regions. Larger size is thought to act as a buffer against colder temperatures: less heat is lost from a body when its mass is large relative to its surface area.

Nature Communications (2021). DOI: 10.1038/s41467-021-24290-7

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Our species, Homo sapiens, emerged around 300,000 years ago in Africa. The genus Homo has existed for much longer, and includes the Neanderthals and other extinct, related species such as Homo habilis and Homo erectus.

https://phys.org/news/2021-07-climate-size-bodies-extent-brains.htm...

Comment by Dr. Krishna Kumari Challa on July 9, 2021 at 8:27am

Certain fish skin can be grafted onto burns and diabetic wounds. The material recruits the body's own cells and is converted eventually into living tissue.

Comment by Dr. Krishna Kumari Challa on July 8, 2021 at 11:21am

The shape of nanoparticles in body fluids may reveal the type of ca...

A recent study by scientists from Japanese universities has shown that the shape of cell-derived nanoparticles, known as "extracellular vesicles" (EVs), in body fluids could be a biomarker for identifying types of cancer. In the study, the scientists successfully measured the shape distributions of EVs derived from liver, breast, and colorectal cancer cells, showing that the shape distributions differ from one another. The findings were recently published in the journal Analytical Chemistry.

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