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Comment by Dr. Krishna Kumari Challa on May 3, 2025 at 6:59am

In extreme conditions, heat does not flow between materials—it bounces off

A new study published in Nature Communications shows, for the first time, how heat moves—or rather, doesn't—between materials in a high-energy-density plasma state.

The work is expected to provide a better understanding of inertial confinement fusion experiments, which aim to reliably achieve fusion ignition on Earth using lasers. How heat flows between a hot plasma and a material's surface is also important in other technologies, including semiconductor etching and vehicles that fly at hypersonic speeds.

High-energy-density plasmas are produced only at extreme pressures and temperatures. The study shows that interfacial thermal resistance, a phenomenon known to impede heat transfer in less extreme conditions, also prevents heat flow between different materials in a dense, super-hot plasma state.

Researchers focused on how heat moves between metal and plastic heated to extreme temperatures and pressures. 

In their experiment, the tungsten wire was heated to about 180,000 degrees Fahrenheit while its plastic coating remained relatively cool at "only" 20,000 degrees Fahrenheit. Using a series of laser shots with progressively delayed timing, the researchers were able to see if the heat was moving between the tungsten and plastic.

When they looked at the data, they were totally shocked because the heat was not flowing between these materials. It was getting stuck at the interface between the materials. 

The reason was interfacial thermal resistance. The electrons in the hotter material arrive at the interface between the materials carrying thermal energy but then scatter off and move back into the hotter material.

Cameron H. Allen et al, Measurement of interfacial thermal resistance in high-energy-density matter, Nature Communications (2025). DOI: 10.1038/s41467-025-56051-1

https://vimeo.com/1065285809

Comment by Dr. Krishna Kumari Challa on May 3, 2025 at 6:52am

Next, researchers isolated target antibodies from the donor's blood that reacted with neurotoxins found within the snake species tested. One by one, the antibodies were tested in mice envenomated from each species included in the panel. In this way, scientists could systematically build a cocktail comprising a minimum but sufficient number of components to render all the venoms ineffective.

The team formulated a mixture comprising three major components: two antibodies isolated from the donor and a small molecule. The first donor antibody, called LNX-D09, protected mice from a lethal dose of whole venom from six of the snake species present in the panel.

To strengthen the antiserum further, the team added the small molecule varespladib, a known toxin inhibitor, which granted protection against an additional three species. Finally, they added a second antibody isolated from the donor, called SNX-B03, which extended protection across the full panel.

Moreover, their results suggest that the three-part cocktail could be effective against many other, if not most, elapid snakes not tested in this study.

Snake-venom protection by a cocktail of varespladib and broadly neutralizing human antibodies, Cell (2025). DOI: 10.1016/j.cell.2025.03.050. www.cell.com/cell/fulltext/S0092-8674(25)00402-7

Part 2

Comment by Dr. Krishna Kumari Challa on May 3, 2025 at 6:46am

Scientists develop antivenom that neutralizes the neurotoxins of 19 of the world's deadliest snakes

By using antibodies from a human donor with a self-induced hyper-immunity to snake venom, scientists have developed the most broadly effective antivenom to date, which is protective against the likes of the black mamba, king cobra, and tiger snakes in mouse trials. Described in the journal Cell, the antivenom combines protective antibodies and a small molecule inhibitor and opens a path toward a universal antiserum.

How we make antivenom has not changed much over the past century. Typically, it involves immunizing horses or sheep with venom from a single snake species and collecting the antibodies produced. While effective, this process could result in adverse reactions to the non-human antibodies, and treatments tend to be species and region-specific.

While exploring ways to improve this process, scientists stumbled upon someone hyper-immune to the effects of snake neurotoxins. The donor, for a period of nearly 18 years, had undertaken hundreds of bites and self-immunizations with escalating doses from 16 species of very lethal snakes that would normally kill a horse.

After the donor, Tim Friede, agreed to participate in the study, researchers found that by exposing himself to the venom of various snakes over several years, he had generated antibodies that were effective against several snake neurotoxins at once.

What 's exciting about the donor 's his once-in-a-lifetime unique immune history. Not only did he potentially create these broadly neutralizing antibodies, in this case, it could give rise to a broad-spectrum or universal antivenom.

To build the antivenom, the team first created a testing panel with 19 of the World Health Organization's category 1 and 2 deadliest snakes across the elapid family, a group which contains roughly half of all venomous species, including coral snakes, mambas, cobras, taipans, and kraits.

Part 1

Comment by Dr. Krishna Kumari Challa on May 3, 2025 at 6:18am

Breath-hold diving not only limits the body's oxygen supply but also raises divers' blood pressure during a dive, the researchers say. Holding one's breath in other contexts, such as sleep apnea, is associated with pregnancy-related blood pressure disorders, although it's unknown whether diving causes the same effect.

The researchers speculate that if the genetic change helps lower blood pressure, it could be especially vital for the Haenyeo. These women dive throughout pregnancy and must avoid blood pressure conditions such as preeclampsia, which can be fatal.

This is not something that every human or every woman is able to do. It's kind of like they have a superpower, courtesy, their genes and practice.

A second genetic difference is related to pain tolerance—specifically, cold-based pain. Air temperatures off Jeju Island drop to around freezing in the winter, but the Haenyeo don't stop diving. 

The genetic differences that could boost diving ability are found throughout the population of Jeju Island. But much of what makes the Haenyeo women special comes from a lifetime of practice.

Researchers have long known that when anyone dives—trained or untrained, Haenyeo or not—their heart rate reflexively drops to conserve oxygen for longer. For an average untrained person from Jeju Island, heartbeat slows down by about 20 beats per minute over the course of a simulated dive. For Haenyeo with a lifetime of diving experience, heart rate drops by up to twice that.

The researchers hope that their discovery of a genetic difference linked to blood pressure will ultimately advance care for health conditions, like stroke, that are related to high blood pressure.

Genetic and Training Adaptations in the Haenyeo Divers of Jeju, Korea, Cell Reports (2025). DOI: 10.1016/j.celrep.2025.115577. www.cell.com/cell-reports/full … 2211-1247(25)00348-1

Part 2

Comment by Dr. Krishna Kumari Challa on May 3, 2025 at 6:14am

Genetic analysis of all-women extreme divers finds changes linked to blood pressure and cold tolerance

A new analysis of a group of all-women extreme divers off the coast of Korea has uncovered genetic differences that could help them survive the intense physiological stresses of free-diving—and could ultimately lead to better treatments for blood pressure disorders.

The researchers worked with the Haenyeo: women who have spent their whole lives diving in the waters off Jeju Island, 50 miles south of mainland South Korea. They free-dive up to 60 feet below the surface to harvest seaweed, abalone, and other food items from the seafloor, spending hours a day in the water all year round.

For hundreds of years, Haenyeo diving was a staple of Jeju's economy and culture, although the practice is now waning.

They're absolutely extraordinary women, say the researchers. Every day, they head out and get in the water, and that's where they work all day. Surprisingly women over 80 dive off a boat before it even stopped moving.

To figure out if the Haenyeo's diving abilities are aided by differences in genetics, the researchers measured physiological variables related to diving ability, such as blood pressure and heart rate. They then sequenced participants' DNA—and found two changes related to diving physiology that could give the Haenyeo advantages underwater.

Haenyeo divers are more than four times more likely than mainland Koreans to have a genetic change associated with lower blood pressure while diving. The researchers think this difference could keep divers and their unborn children safe when diving during pregnancy.

Part 1

Comment by Dr. Krishna Kumari Challa on May 2, 2025 at 3:02pm

The findings could have far-reaching implications on our understanding of the role of cell division in disease. For example, in the context of cancer cells, this type of "non-round," asymmetric division could generate different cell behaviors known to promote cancer progression through metastasis.

Harnessing this information could also impact regenerative medicine, enabling us to better manufacture the cell types needed to regenerate damaged tissues and organs. Scientists may one day be able to influence the function of daughter cells by simply manipulating their parental cell shape.

Holly E. Lovegrove et al, Interphase cell morphology defines the mode, symmetry, and outcome of mitosis, Science (2025). DOI: 10.1126/science.adu9628. www.science.org/doi/10.1126/science.adu9628

Part 2

Comment by Dr. Krishna Kumari Challa on May 2, 2025 at 3:01pm

Re-writing textbooks: New insights into cell division

Scientists  have changed our understanding of how cells in living organisms divide, which could revise what students are taught at school. In a study published this week in Science, the researchers challenge conventional wisdom taught in schools for over 100 years.

Students are currently taught that during cell division, a parent cell will become spherical before splitting into two daughter cells of equal size and shape. However, the study reveals that cell rounding is not a universal feature of cell division and is not how it often works in the body.

Dividing cells, the researchers show, often don't round up into sphere-like shapes. This lack of rounding breaks the symmetry of division to generate two daughter cells that differ from each other in both size and function, known as asymmetric division.

Asymmetric divisions are an important way that the different types of cells in the body are generated, to make different tissues and organs. Until now, asymmetric cell division has predominantly only been associated with highly specialized cells, known as stem cells.

The scientists found that it is the shape of a parent cell before it even divides that can determine if they will round or not in division and determines how symmetric—or not—its daughter cells will be. Cells that are shorter and wider in shape tend to round up and divide into two cells which are similar to each other. However, cells that are longer and thinner don't round up and divide asymmetrically, so that one daughter is different from the other.

Part 1

Comment by Dr. Krishna Kumari Challa on May 2, 2025 at 2:48pm

Size and chemical makeup determine which ancient animals fossilize

Why do some ancient animals become fossils while others disappear without a trace? A new study  published in Nature Communications, reveals that part of the answer lies in the body itself. The research shows that an animal's size and chemical makeup can play an important role in determining whether it's preserved for millions of years—or lost to time.

Fossils are more than just bones; some of the most remarkable finds include traces of soft tissues like muscles, guts, and even brains. These rare fossils offer vivid glimpses into the past, but scientists have long puzzled over why such preservation happens only for certain animals and organs but not others.

To dig into this mystery, a team of scientists turned to the lab. They conducted state-of-the-art decay experiments, allowing a range of animals including shrimps, snails, starfish, and planarians (worms) to decompose under precisely controlled conditions.

As the bodies broke down, the researchers used micro-sensors to monitor the surrounding chemical environment, particularly the balance between oxygen-rich (oxidizing) and oxygen-poor (reducing) conditions.

The results were striking. The researchers discovered that larger animals and those with a higher protein content tend to create reducing (oxygen-poor) conditions more rapidly. These conditions are crucial for fossilization because they slow down decay and trigger chemical reactions such as mineralization or tissue replacement by more durable minerals.

This means that, in nature, two animals buried side by side could have vastly different fates as fossils, simply because of differences in size or body chemistry. One might vanish entirely, while the other could be immortalized in stone.

According to this study, animals such as large arthropods are more likely to be preserved than small planarians or other aquatic worms. This could explain why fossil communities dating from the Cambrian and Ordovician periods (around 500 million years ago) are dominated by arthropods.

These findings not only help explain the patchy nature of the fossil record but also offer valuable insight into the chemical processes that shape what ancient life we can reconstruct today. Pinpointing the factors that drive soft-tissue fossilization brings us closer to understanding how exceptional fossils form—and why we only see fragments of the past.

 Nora Corthésy et al, Taxon-specific redox conditions control fossilisation pathways, Nature Communications (2025). DOI: 10.1038/s41467-025-59372-3

Comment by Dr. Krishna Kumari Challa on May 2, 2025 at 2:30pm

Skin wounds in humans found to heal nearly three times slower than those in other primates

A team of evolutionary scientists, dermatologists and wildlife specialists has found that human skin wounds take nearly three times as long to heal as they do in other primates. In their study, published in the journal Proceedings of the Royal Society B: Biological Sciences, the group conducted experiments involving skin healing speed in humans and several other primates.

Prior research  suggest that other animals recover from skin wounds faster than humans. In this new effort, the research team sought to measure such differences.

The experiments involved comparing skin wounds in humans—courtesy of volunteers at a hospital undergoing skin tumor removal—and several primates. Wound healing pace in chimpanzees was measured by studying chimps housed at a sanctuary who endured skin wounds periodically due to fighting between males.

In looking at the data, the researchers found that all the test subjects healed at nearly the same rate—0.62 millimeters of new skin growth a day—except for humans, who healed at an average of 0.25 millimeters per day. The researchers also tested mice and rats and found their healing rates were similar to those of non-human primates.

The research team suggests the reason for the difference lies in humans having lost their fur. They note that hair follicle stem cells can grow skin cells when needed. Humans have replaced most of their hair follicles with sweat glands, which also have stem cells that can grow into skin cells, but do so far less efficiently.

As humans lost their fur, the researchers note, they replaced them with sweat glands to prevent overheating. The trade-off was obviously worth it, or humans would be covered in fur today. They also note that the expanding brain may have helped along the way, providing humans with the ability to treat skin wounds in ways other animals cannot.

Akiko Matsumoto-Oda et al, Inter-species differences in wound-healing rate: a comparative study involving primates and rodents, Proceedings of the Royal Society B: Biological Sciences (2025). DOI: 10.1098/rspb.2025.0233

Comment by Dr. Krishna Kumari Challa on May 1, 2025 at 10:21am

When looking at the likelihood of having a fatal or a serious injury, as compared to a slight injury, the likelihood increased by around a quarter (odds 24% higher in adults and 28% higher in children) for those hit by an SUV or LTV. These effects were all similar for both pedestrians and cyclists.

Previous research indicates that a key mechanism for this increased risk is likely to be the taller and blunter profile of the front end of SUVs and LTVs. A taller front end means that a pedestrian or cyclist is struck higher up on their body (e.g. the pelvis not the knees for an adult, or the head not the pelvis for a child).

A taller and blunter front end also means that the pedestrian or cyclist is more likely to be thrown forward onto the road, at which point the striking vehicle may hit them a second time or roll over their body.
If all SUVs were replaced with passenger cars, the number of pedestrians and cyclists killed in car crashes would decrease, say the researchers.

 Do sports utility vehicles (SUVs) and light truck vehicles (LTVs) cause more severe injuries to pedestrians and cyclists than passenger cars in the case of a crash? A systematic review and meta-analysis, Injury Prevention (2025). DOI: 10.1136/ip-2024-045613

Part 2

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