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Comment by Dr. Krishna Kumari Challa on February 19, 2023 at 11:14am

Fun science: Physics

Here’s something that’s really amazing, but it also takes a bit of skill and patience too! How can you pick up a ball with a glass without touching the ball itself? Place the glass over the ball and then start spinning the glass around in a circular motion. Once the ball starts spinning inside the glass, lift it from the table. Watch out! If the ball isn’t spinning enough, then you won’t be able to lift it.

This is the explanation:

The Spinning Ball experiment Place the jar over the ball so that the ball is inside the mouth of the canning jar. Then start spinning the glass around in a circular motion Once the ball starts spinning inside the glass lift it from the table top. The ball is lifted from the table and will continue to spin inside the glass until it loses is speed. As a ball velocity increases inside the glass, the centripetal force increases. That force is what's keeping the ball stuck to the walls of the glass. As the ball goes faster, the resulting friction begins to cancel out the force of gravity acting on the ball. The centripetal force and friction, and those factors rely on velocity. If the ball goes too slowly, the velocity won't increase enough to out-do the force of gravity, and the ball will fall out of the glass.

Comment by Dr. Krishna Kumari Challa on February 18, 2023 at 12:51pm

Blood stem cells shown to be susceptible to ferroptosis, a type of cell death

The body is constantly replenishing the blood with new red and white blood cells thanks to a small but important group of cells called hematopoietic stem cells (HSCs). Now, researchers have found that these cells are particularly vulnerable to ferroptosis, a kind of cell death triggered by iron.

Scientists have studied ferroptosis mostly in cancer cells, but this study, published recently in the journal Cell, is one of the first to show that a normal cell type is also susceptible to this form of cell death. The findings also point to potential side effects of drugs that are being developed to boost ferroptosis to kill cancer cells. And they suggest new strategies for treating blood disorders caused by low levels of HSCs.

The research team first discovered this ferroptosis vulnerability in a rare bone marrow disorder, but were surprised to find this feature in healthy HSCs as well. They also found that this susceptibility arises from the cells' decreased rate of protein production.

This is a good example where a rare disease can teach us much more about fundamental biological processes that we wouldn't have discovered otherwise.

Jiawei Zhao et al, Human hematopoietic stem cell vulnerability to ferroptosis, Cell (2023). DOI: 10.1016/j.cell.2023.01.020

Comment by Dr. Krishna Kumari Challa on February 18, 2023 at 11:10am

Evolution: Mini-proteins in human organs appeared 'from nowhere'

Every biologist knows that small structures can sometimes have a big impact: Millions of signaling molecules, hormones, and other biomolecules are bustling around in our cells and tissues, playing a leading role in many of the key processes occurring in our bodies. Yet despite this knowledge, biologists and physicians long ignored a particular class of proteins—their assumption being that because the proteins were so small and only found in primates, they were insignificant and functionless.

However, the discoveries recently made changed this view. The existence of thousands of new microproteins in human organs has been established now.

Bioinformatic gene analyses revealed that most human microproteins developed millions of years later in the evolutionary process than the larger proteins currently known to scientists.

Yet the huge age gap doesn't appear to prevent the proteins from "talking" to each other. Lab experiments showed that the young and old proteins can bind to each other—and in doing so possibly influence each other.  The ability to bind does suggest the proteins might influence each other's functioning.

Unlike the known, old proteins that are encoded in our genome, most microproteins emerged more or less "out of nowhere—in other words, out of DNA regions that weren't previously tasked with producing proteins.

And because these small proteins only emerged during human evolution, they are missing from the cells of most other animals, such as mice, fish and birds. These animals, however, have been found to possess their own collection of young, small proteins.

During their work, the researchers also discovered the smallest human proteins identified to date. They found over 200 super-small proteins, all of which are smaller than 16 amino acids.

Scientists therefore suspect that contrary to long-held assumptions, the microproteins play a key role in a variety of cellular functions. The young proteins might also be heavily involved in evolutionary development thanks to comparatively rapid "innovations and adaptations."

It's possible that evolution is more dynamic than previously thought.

Norbert Hubner & colleauges, Evolutionary origins and interactomes of human young microproteins and small peptides translated from short open reading frames, Molecular Cell (2023). DOI: 10.1016/j.molcel.2023.01.023. www.cell.com/molecular-cell/fu … 1097-2765(23)00075-8

Comment by Dr. Krishna Kumari Challa on February 17, 2023 at 11:40am

Keeping drivers safe with a road that can melt snow, ice on its own

Slipping and sliding on snowy or icy roads is dangerous. Salt and sand help melt ice or provide traction, but excessive use is bad for the environment. And sometimes, a surprise storm can blow through before these materials can be applied. Now, researchers reporting in ACS Omega have filled microcapsules with a chloride-free salt mixture that's added into asphalt before roads are paved, providing long-term snow melting capabilities in a real-world test.

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Driving on snowy roads at or near-freezing temperatures can create unsafe conditions, forming nearly invisible, slick black ice, if roads aren't cleaned quickly enough. But the most common ways to keep roads clear have significant downsides:

• Regular plowing requires costly equipment, is labor intensive and can damage pavement.
• Heavy salt or sand applications can harm the environment.
• Heated pavement technologies are prohibitively expensive to use on long roadways.

Recently, researchers have incorporated salt-storage systems into "anti-icing asphalt" to remove snow and prevent black ice from forming. However, these asphalt pavements use corrosive chloride-based salts and only release snow-melting substances for a few years.

So now they now wanted to develop a longer-term, chloride-free additive to effectively melt and remove snow cover on winter roads.

The researchers prepared a sodium acetate salt and combined it with a surfactant, silicon dioxide, sodium bicarbonate and blast furnace slag—a waste product from power plant operations—to produce a fine powder. They then coated the particles in the powder with a polymer solution, forming tiny microcapsules. Next, the team replaced some of the mineral filler in an asphalt mixture with the microcapsules. In initial experiments, a pavement block made with the new additive lowered the freezing point of water to -6 F. And the researchers estimated that a 5-cm-thick layer of the anti-icing asphalt would be effective at melting snow for seven to eight years. A real-world pilot test of the anti-icing asphalt on the off-ramp of a highway showed that it melted snow that fell on the road, whereas traditional pavement required additional removal operations. Because the additive used waste products and could release salt for most of a road's lifetime, the researchers say that is a practical and economic solution for wintertime snow and ice removal.

 Yingfei Zhao et al, Preparation of a Green Sustained-Release Microcapsule-Type Anti-Icing Agent for Asphalt Pavement and Its Application Demonstration Project, ACS Omega (2023). DOI: 10.1021/acsomega.2c07212

Comment by Dr. Krishna Kumari Challa on February 17, 2023 at 11:35am

Climate lessons from the last global warming

The Earth experienced one of the largest and most rapid climate warming events in its history 56 million years ago: the Paleocene-Eocene Thermal Maximum (PETM), which has similarities to current and future warming. This episode saw global temperatures rise by 5°C–8°C. It was marked by an increase in the seasonality of rainfalls, which led to the movement of large quantities of clay into the ocean, making it uninhabitable for certain living species.

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Engineered wood grows stronger while trapping carbon dioxide

Rice University scientists have figured out a way to engineer wood to trap carbon dioxide through a potentially scalable, energy-efficient process that also makes the material stronger for use in construction.

Comment by Dr. Krishna Kumari Challa on February 17, 2023 at 11:28am

Researchers develop a novel 2D material that uses a virus to kill cancer cells

Electro-thermal therapy, which involves applying electrical signals to nanomaterials, provides high cancer cell targeting accuracy and is highly bio-compatible. In this research, scientists have designed a novel thermal-based therapy nano-system that destroys more than 20% of pancreatic cancer cells using microsecond electrical pulses and with excellent bio-compatibility.

Electro-thermal therapy works by injecting two dimensional (2D) materials in cancer cells and applying electrical currents to the cells. This causes the materials to heat up and kill neighboring cancer cells. Traditional electro-thermal therapy with 2D materials however, can fail as a result of weak cancer cell ablation. This is due to the limited amount of materials assembled on the cancer cells and the weak Joule heating generated in the material.

To alleviate these issues, the researchers deposited the M13 virus on molybdenum disulfide (MoS₂) layered materials to create a hybrid nanomaterial MoS₂ Nanostructure with M13 virus (the authors call it MNM). Moreover, they altered the nanomaterial surfaces with polyethylene glycol (PEG) to improve bio-compatibility.

The introduction of the M13 virus improves the electro-thermal therapy performance. Compared to conventional 2D materials, a larger amount of MNM assembles on the cancer cells due to the higher specificity of the binding of the M13 virus to cancer cells. Due to the high electrical conductivity of the MoS₂ material, a strong Joule heating is also generated.

As a result, a larger amount of heat is produced in the nanomaterials, and can be used to kill a larger population of the cancer cells. For example, the MNM nanosystem can decrease the percentage of cancer cells by 23%, which is approximately 2 times higher than what current thermal-based therapy nano-systems can do.

Maria P. Meivita et al, An Efficient, Short Stimulus PANC-1 Cancer Cell Ablation and Electrothermal Therapy Driven by Hydrophobic Interactions, Pharmaceutics (2022). DOI: 10.3390/pharmaceutics15010106

Comment by Dr. Krishna Kumari Challa on February 17, 2023 at 11:23am

Nanoparticles perform ultralong distance communication, have 'no counterpart or analogue in nature'

Chemists have designed a new photonic lattice with properties never before seen in nature. In solid materials, atoms must be equally spaced apart and close enough together to interact effectively. Now, new architectures based on stacked lattices of nanoparticles show interactions across unprecedentedly large distances.

When one lattice is stacked on top of the other, the nanoparticles can still interact with each other—even when the vertical separation among particles is 1,000 times the distance of the particle-to-particle spacing within the horizontal plane.

Because the nanoparticles can communicate across ultralong distances, the stacked architecture offers potential applications in remote sensing and detection.

This type of long-range coupling has not been observed before for any stacked periodic material. Other electronic or photonic stacked layers are separated vertically by a spacing similar to the horizontal periodicity of the building unit in the single layer. This is an entirely new class of engineered materials that have no counterpart or analogue in nature.

Jun Guan et al, Far-field coupling between moiré photonic lattices, Nature Nanotechnology (2023). DOI: 10.1038/s41565-023-01320-7

Comment by Dr. Krishna Kumari Challa on February 17, 2023 at 9:59am

Novel method to accurately measure key marker of biological aging

Telomeres—the caps at the ends of chromosomes that protect our genetic materials from the brunt of cellular wear and tear—are known to shorten and fray over time. Lifestyle, diet and stress can exacerbate this process, leading to early loss of telomere protection and increasing the chances of early aging and diseases, such as cancer and heart disease.

To date, approaches for measuring biological aging based on telomere length have been limited as they can only ascertain average telomere lengths within a pool of DNA fragments, or they are time-consuming and require highly-skilled specialists. Being able to accurately and efficiently measure the length of an individual's telomeres could open the doors to developing lifestyle interventions that slow aging and prevent disease.

Scientists have recently devised a way to rapidly and precisely measure the length of a single telomere.

They applied a novel approach that uses DNA sequences—they call them 'telobaits'—to latch onto the ends of telomeres in large pools of DNA fragments, like fishing in pond. Then, with specific scissor-like enzymes, they snip the telomeres out of the pools.

Using high-throughput genetic sequencing technology, they were able to read the DNA 'letters' that comprised each individual telomere, allowing them to very precisely measure their lengths.

The team successfully validated this approach when they tested it using human cell lines and patient cells. Interestingly, the sequencing results revealed that the genetic sequences within certain parts of the telomeres, known as telomeric variant sequences, were distinct to each individual person.

The researchers think this new approach could be used as a predictive biomarker for human aging and disease at the individual level, as well as for population-level studies on the impacts of lifestyle, diet and the environment on human health.

Cheng-Yong Tham et al, High-throughput telomere length measurement at nucleotide resolution using the PacBio high fidelity sequencing platform, Nature Communications (2023). DOI: 10.1038/s41467-023-35823-7

Comment by Dr. Krishna Kumari Challa on February 17, 2023 at 9:48am

Next, in a series of experiments, the researchers demonstrated that the aggression-mirroring neurons not only sensed aggression but enabled it. When they selectively inhibited these neurons, mice were less irked by a male intruder—and initiated only a third as many attacks or tail-rattles as normal mice.

Inversely, when the mirror neurons were switched on, the mice became indiscriminately aggressive. Not only did they initiate three times more attacks on male intruders than usual, they attacked even female visitors, who normally would have prompted frisky coupling behavior. Needless to say, they were less successful in mating. The male mice were so riled up they even tail-rattled at their own mirror reflection.

It tells you that the activity of these neurons is sufficient for aggression, even when there's no provocation. 

The fact that aggression-mirroring neurons exist in such a primitive part of the brain indicates they may have been conserved across evolution, from mouse to human. It suggests that we might have the same neurons, and maybe they encode some qualities of aggression in ourselves. 

The researchers did not investigate how observing aggressive behavior affected the observers, but they offer their own speculation—perhaps, like boxers studying videos of their opponent's moves, the mice on the sidelines learn to be better fighters.

Taehong Yang et al, Hypothalamic neurons that mirror aggression, Cell (2023). DOI: 10.1016/j.cell.2023.01.022

Part 2

Comment by Dr. Krishna Kumari Challa on February 17, 2023 at 9:46am

Scientists discover mirror neurons in mice and find they're tuned to aggression

In nature, when two animals fight, they are seldom without an audience. 

Researchers wanted to know how the animals on the sidelines perceive these aggressive interactions. In a new study in mice, they discovered that some neurons in a part of the brain known as the "rage center" fire both when a mouse is fighting and when it watches others fight. Such neurons are known as mirror neurons—they are active when an animal is doing the behaviour and when it's watching another animal do that same behaviour.

The study is the first to find mirror neurons in mice and in the hypothalamus—an evolutionarily ancient part of the brain—hinting at a more primal origin for mirror neurons than previously thought.

Aggression in the wild is rarely a private affair. Aggression is usually not only to defeat the other animal, but also to tell others in the vicinity, 'Hey, I'm the boss.' It's a public display. Previous work  traced aggression in male mice to a cluster of brain cells in a part of the ventromedial hypothalamus. (In female mice, the same neurons do not trigger aggression.) Dubbed the "rage center," these neurons could activate aggression, but also seemed sensitive to a mouse's socialization—communally housed mice were less aggressive. 

What else are these neurons sensitive to? Researchers proposed that these neurons might be sensitive to aggression between other mice.

And that turned out to be the case: They're mirroring aggression by other animals. 

Using precise imaging techniques, the researchers recorded activity in the rage center of male mice engaged in a brawl and those witnessing a fight.

Sparking a fight between male mice is simple—the researchers had only to introduce a male mouse into another's cage. The resident mouse would attack the intruder and display threatening behavior, like tail-rattling. To set up a witness, the researchers allowed a lone mouse to observe these fights through a transparent divider.

They found that a nearly identical set of neurons in the rage center were active in both fighters and observers—qualifying them as mirror neurons.

Another surprise was that in an observer, aggression-mirroring neurons were triggered by sight, whereas in fighting mice, they are triggered by the smell of pheromones. Video recordings revealed that mirror neurons fired only in the moments when the observer was facing the fighters, not when it was turned away. And when the researchers turned off the lights, the observer's mirror neurons were entirely unresponsive to the fracas next door.

The researchers found also that these mirror neurons seemed innately tuned to aggression, even in mice that had never witnessed or engaged in aggressive behavior. They did not fire when mice watched other behaviors, like sniffing, grooming or running on a wheel.

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