Comment

Comment by Dr. Krishna Kumari Challa on March 12, 2025 at 9:14am

Comment by Dr. Krishna Kumari Challa on March 12, 2025 at 9:09am

Majority of the world's population breathes dirty air, report says

Most of the world has dirty air, with just 17% of cities globally meeting air pollution guidelines, a recent report found.

Switzerland-based air quality monitoring database IQAir analyzed data from 40,000 air quality monitoring stations in 138 countries and found that Chad, Congo, Bangladesh, Pakistan and India had the dirtiest air. India had six of the nine most polluted cities with the industrial town of Byrnihat in northeastern India the worst.

Experts said the real amount of air pollution might be far greater as many parts of the world lack the monitoring needed for more accurate data.

More air quality monitors are being set up to counter the issue, the report said. This year, report authors were able to incorporate data from 8,954 new locations and around a thousand new monitors as a result of efforts to better monitor air pollution.

But last week, data monitoring for air pollution was dealt a blow when the U.S. State Department announced it would no longer make public its data from its embassies and consulates around the world.

Breathing in polluted air over a long period of time can cause respiratory illness, Alzheimer's disease and cancer. The World Health Organization estimates that air pollution kills around 7 million people each year.

Experts say that much more needs to be done to cut air pollution levels. The WHO had earlier found that 99% of the world's population lives in places that do not meet recommended air quality levels.

And the problem is if you have bad water, no water, you can tell people to wait for half an hour a day, the water will come. But if you have bad air, you cannot tell people to pause breathing.

Several cities like Beijing, Seoul, South Korea, and Rybnik in Poland have successfully improved their air quality through stricter regulations on pollution from vehicles, power plants and industry. They've also promoted cleaner energy and invested in public transportation.

Source: News agencies

Comment by Dr. Krishna Kumari Challa on March 12, 2025 at 9:01am

How hand shape affects sound while clapping

New research work published in Physical Review Research,  elucidates the complex physical mechanisms and fluid dynamics involved in a handclap, with potential applications in bioacoustics and personal identification, whereby a handclap could be used to identify someone.

The researchers used high-speed cameras to track the hand motion, air flow and sound of 10 volunteers clapping, measuring the different frequencies when the size and shape of the cavity between hands changes: when clapping with cupped hands, flat hands or fingers to palm. They found the larger the cavity between palms, the lower the frequency of the clap, with the hands acting as a resonator—whereby the sound comes from the force of air through the hand's cavity and the opening between the thumb and index finger.

It's the air column pushed by this jet flow of air coming out of the hand cavity that causes the disturbance in the air, and that's the sound we hear.

The researchers compared the human data to that produced with simplified replicas, as well as theoretical projections of how air would move through a traditional resonator, called a Helmholtz resonator.

They confirmed both experimentally and computationally that the Helmholtz resonator can predict the frequency of the human handclap.

It's a confirmation of this unifying principle that may be helpful in other fields, especially bioacoustics, because that principle may help explain all kinds of bioacoustics phenomena, especially those involving soft material collision and jet flow.

Additionally, the researchers studied why claps are so short, compared to sound made through a traditional resonator, finding that the softness of the hands plays a role: the soft tissues of the hands vibrate after impact, absorbing energy and dampening the sound.

When there's more vibration in the material, the sound attenuates much more quickly. So, if you want to get the attention of another person very far from you, and you want the sound to last longer, you might want to choose a certain type of handclapping shape that makes your hand more rigid.

The research further opens the door to the idea of using a handclap as a personal identifier or signature.

The handclap is actually a very characteristic thing, because we have different sizes of hand, techniques, different skin textures and softness—that all results in different sound performances. Now that we understand the physics of it, we can use the sound to identify the person.

Yicong Fu et al, Revealing the sound, flow excitation, and collision dynamics of human handclaps, Physical Review Research (2025). DOI: 10.1103/PhysRevResearch.7.013259

Comment by Dr. Krishna Kumari Challa on March 12, 2025 at 8:53am

Scientists discover smart way to generate energy with tiny plastic beads

An international team of researchers has discovered a new method to generate electricity using small plastic beads. By placing these beads close together and bringing them into contact, they generate more electricity than usual. This process, known as triboelectrification, is similar to the static electricity produced when rubbing a balloon against hair.

Triboelectric nanogenerators (TENGs) generate electricity through friction between different materials. Typically, this occurs when two distinct materials move against each other. The research now shows that when a surface made up of closely packed small beads comes into contact with another surface containing the same beads, some beads gain a positive charge while others become negatively charged. The more efficiently these electric charges transfer, the more electricity is produced.

Tests with different types of beads reveal that size and material play a crucial role. Larger beads tend to acquire a negative charge, whereas smaller ones are more likely to become positively charged. The most significant effect occurs with melamine-formaldehyde (MF) beads.

This material has low elasticity, meaning it is less flexible and better at holding and transferring electric charge. Additionally, using beads provides a cost-effective alternative to the expensive technology typically used in TENGs to enhance performance. The dry fabrication of particles also makes the process more sustainable by eliminating the need for solvents.

Advancements in triboelectrification could enable new energy-harvesting applications without batteries or power outlets.

Ignaas S. M. Jimidar et al, Granular Interfaces in TENGs: The Role of Close‐Packed Polymer Bead Monolayers for Energy Harvesters, Small (2025). DOI: 10.1002/smll.202410155

Comment by Dr. Krishna Kumari Challa on March 12, 2025 at 8:49am

Microplastics could be fueling antibiotic resistance

Microplastics—tiny shards of plastic debris—are all over the planet. They have made their way up food chains, accumulated in oceans, clustered in clouds and on mountains, and been found inside human bodies at alarming rates. Scientists have been racing to uncover the unforeseen impacts of so much plastic in and around us.

One possible, and surprising, consequence: more drug-resistant bacteria.

In a startling discovery, a team of  researchers found that bacteria exposed to microplastics became resistant to multiple types of antibiotics commonly used to treat infections. They say this is especially concerning for people in high-density, impoverished areas like refugee settlements, where discarded plastic piles up and bacterial infections spread easily.

The study is published in Applied and Environmental Microbiology.

The fact that there are microplastics all around us, and even more so in impoverished places where sanitation may be limited, is a striking part of this observation.

There is certainly a concern that this could present a higher risk in communities that are disadvantaged, and only underscores the need for more vigilance and a deeper insight into [microplastic and bacterial] interactions.

The plastics provide a surface that the bacteria attach to and colonize. 

Once attached to any surface, bacteria create a biofilm—a sticky substance that acts like a shield, protecting the bacteria from invaders and keeping them affixed securely.

Even though bacteria can grow biofilms on any surface, researchers observed that the microplastic supercharged the bacterial biofilms so much that when antibiotics were added to the mix, the medicine was unable to penetrate the shield.

The researchers  found that the biofilms on microplastics, compared to other surfaces like glass, are much stronger and thicker, like a house with a ton of insulation.

The rate of antibiotic resistance on the microplastic was so high compared to other materials, that the researchers performed the experiments multiple times, testing different combinations of antibiotics and types of plastic material. Each time, the results remained consistent.

They conclusively demonstrated that the presence of plastics is doing a whole lot more than just providing a surface for the bacteria to stick to—they are actually leading to the development of resistant organisms.

 Effects of microplastic concentration, composition, and size on Escherichia coli biofilm- associated antimicrobial resistance, Applied and Environmental Microbiology (2025). DOI: 10.1128/aem.02282-24

Comment by Dr. Krishna Kumari Challa on March 12, 2025 at 8:37am

Beneficial genetic changes observed in regular blood donors

Researchers have identified genetic changes in blood stem cells from frequent blood donors that support the production of new, non-cancerous cells.

Understanding the differences in the mutations that accumulate in our blood stem cells as we age is important to understand how and why blood cancers develop and hopefully how to intervene before the onset of clinical symptoms.

As we age, stem cells in the bone marrow naturally accumulate mutations and with this, we see the emergence of clones, which are groups of blood cells that have a slightly different genetic makeup. Sometimes, specific clones can lead to blood cancers like leukemia.

When people donate blood, stem cells in the bone marrow make new blood cells to replace the lost blood and this stress drives the selection of certain clones.

In research published Blood, the research team analyzed blood samples taken from over 200 frequent donors—people who had donated blood three times a year over 40 years, more than 120 times in total—and sporadic control donors who had donated blood less than five times in total.

Samples from both groups showed a similar level of clonal diversity, but the makeup of the blood cell populations was different.

For instance, both sample groups contained clones with changes to a gene called DNMT3A, which is known to be mutated in people who develop leukemia. Interestingly, the changes to this gene observed in frequent donors were not in the areas known to be preleukemic.

To understand this better, the  researchers edited DNMT3A in human stem cells in the lab. They induced the genetic changes associated with leukemia and also the non-preleukemic changes observed in the frequent donor group.

They grew these cells in two environments: one containing erythropoietin (EPO), a hormone that stimulates red blood cell production which is increased after each blood donation, and another containing inflammatory chemicals to replicate an infection.

The cells with the mutations commonly seen in frequent donors responded and grew in the environment containing EPO and failed to grow in the inflammatory environment. The opposite was seen in the cells with mutations known to be preleukemic.

This suggests that the DNMT3A mutations observed in frequent donors are mainly responding to the physiological blood loss associated with blood donation.

Finally, the team transplanted the human stem cells carrying the two types of mutations into mice. Some of these mice had blood removed and then were given EPO injections to mimic the stress associated with blood donation.

The cells with the frequent donor mutations grew normally in control conditions and promoted red blood cell production under stress, without cells becoming cancerous. In sharp contrast, the preleukemic mutations drove a pronounced increase in white blood cells in both control or stress conditions.

The researchers believe that regular blood donation is one type of activity that selects for mutations that allow cells to respond well to blood loss, but does not select the preleukemic mutations associated with blood cancer.

Karpova, D. et al. Clonal Hematopoiesis Landscape in Frequent Blood Donors, Blood (2025). DOI: 10.1182/blood.2024027999

Comment by Dr. Krishna Kumari Challa on March 12, 2025 at 7:33am

Overall, telomeres got longer in lemurs that experienced deeper torpor bouts.

By contrast, lemurs that "woke up" to eat had telomere lengths that remained relatively stable during the study.

The lemurs' changes were temporary. Two weeks after the animals made their way out of hibernation, the researchers noted that their telomeres returned to their pre-hibernation length.
Lengthening may be a mechanism to counteract any cell damage that might otherwise occur during their periodic rewarming phases, the researchers say.
By extending their telomeres, lemurs may effectively increase the number of times their cells can divide, thus adding new life to their cells at a stressful time.
It seems to work—dwarf lemurs can live up to twice as long as other primates their size.
figuring out how they do it may help researchers develop new ways to prevent or treat age-related diseases in humans without increasing the risks of runaway cell division that can lead to cancer, the researchers say.

Marina B. Blanco et al, Food deprivation is associated with telomere elongation during hibernation in a primate, Biology Letters (2025). DOI: 10.1098/rsbl.2024.0531

Part 2

Comment by Dr. Krishna Kumari Challa on March 12, 2025 at 7:31am

Hibernating lemurs can turn back the clock on cellular aging

Many age-related changes start within our cells, even our DNA, which can wear and tear over time as we get older. Some creatures have come up with a way to reverse this process, at least temporarily.

Consider the fat-tailed dwarf lemur of Madagascar. This hamster-sized primate can turn back the cellular aging clock and momentarily defy time during its annual hibernation season, according to new research .

The work is published in the journal Biology Letters.

It's thanks to tiny caps on the ends of their chromosomes called telomeres. They work like the plastic tips on the ends of shoelaces that keep them from fraying.

Every time a cell divides, little chunks of its telomeres are lost in the process, such that telomeres get shorter with age.

Things like chronic stress, a sedentary lifestyle and skimping on sleep can make them dwindle even faster. Eventually, telomeres become so stubby that they no longer provide protection, and cells lose the ability to function.

But dwarf lemurs have a way of keeping their telomeres from shortening and even making them longer, effectively rejuvenating their cells, at least for a while, according to the Biology Letters study.

It all happens during hibernation. 

When winter sets in in the wild, dwarf lemurs disappear into tree holes or underground burrows, where they spend up to seven months each year in a state of suspended animation.

It's a survival tactic for making it through times when food is in short supply.

During this period of metabolic slow-motion, their heart rate slows from around 200 beats per minute to fewer than eight, they become cool to the touch, and they only take a breath every 10 minutes or so.

Hibernating dwarf lemurs can stay in this cold, standby state for about a week before they have to briefly warm up, and ironically, this is when they catch up on sleep. Then, they settle back into torpor while waiting for the season of plenty to return.

The researchers followed 15 dwarf lemurs at the Duke Lemur Center before, during, and after hibernation, testing cheek swabs to track how their telomeres changed over time.

Usually, telomere length decreases over time as each round of cell division wears away at them. But genetic sequencing revealed that during hibernation, the lemurs' telomeres weren't shortening—they actually got longer.

It's almost as if, even as the months ticked by, they walked back their cells to a more youthful state.

The results were in the opposite direction of what you'd expect.

Part 1

Comment by Dr. Krishna Kumari Challa on March 12, 2025 at 7:03am

Scientists have previously used expiration dates to track seafloor litter and piece together extreme flood events from the Anthropocene. Building on this idea, the researchers of this study collected abandoned common coot nests from central Amsterdam on September 22, 2021, after the breeding season ended.
Each nest was then deconstructed and its contents were divided into piles of natural (twigs) and artificial (near-complete packaging) materials. Each artificial item was then carefully examined for manufacturing dates, expiration dates, or any other markings that could reveal its age. The recovered packaging ranged from items like milk and avocados to chocolate packets and fast food wrappers dating back to 1996.
The researchers discovered that two of the collected coot nests had very distinct layers of plastic, making them ideal for stratigraphy—study and interpretation of the layers. One of the nests, which the scientists named "The Rokin Nest," contained plastic waste that was over three decades old.
Nestled at the base of the nest was a candy bar wrapper promoting the 1994 FIFA World Cup while the upper more recent layers hosted discarded face masks from the COVID-19 pandemic. This process of layered accumulation of contemporary human waste is also known as technostratigraphy.

Based on the stratigraphy results and tracking of nesting activity via analysis of archived Google Street View images, the researchers arrived at the conclusion that the Rokin Nest must have been home to at least three generations of coots, as their lifespan is somewhere between 5 to 10 years.
Plastic waste has enabled coots to reuse their nests, giving them more time to forage for food and defend their territory, but this luxury comes at a cost. The researchers noted that old nesting material can be host to harmful parasites like red mites and too much plastic in the nest increases the risk of entanglement for the birds, sometimes resulting in death.

 Auke‐Florian Hiemstra et al, Birds documenting the Anthropocene: Stratigraphy of plastic in urban bird nests, Ecology (2025). DOI: 10.1002/ecy.70010

Part 3

Comment by Dr. Krishna Kumari Challa on March 12, 2025 at 6:52am

Archaeological finds are dated using both relative and absolute dating methods, with common techniques including stratigraphy (analyzing the layers of soil and artifacts), radiocarbon dating (measuring carbon-14 decay in organic materials), and dendrochronology (analyzing tree-ring patterns).
Here's a more detailed breakdown of these methods:
Relative Dating:
Stratigraphy:
This method examines the layers of earth or strata where artifacts are found, to understand the chronological order of past human activities. The Law of Superposition states that in undisturbed layers, the deeper a layer is, the older it is.
Seriation:
This method involves arranging artifacts in a chronological sequence based on their similarities, helping to establish a relative timeline.
Cross-dating:
This method compares artifacts from different locations with known dates to establish a timeline.
Absolute Dating:
Radiocarbon Dating:
This method measures the decay of radioactive carbon-14 (C-14) in organic materials like wood, bone, and charcoal, to determine the age of the sample.
Dendrochronology:
This method uses the annual growth rings in trees to create a precise timeline and date wooden artifacts and structures.
Thermoluminescence:
This method dates materials that were heated in the past by measuring the light emitted from mineral crystals.
Archaeomagnetism:
This method analyzes the direction and intensity of Earth's magnetic field as recorded in baked earth or clay to establish the last time the material was heated.
Potassium-Argon Dating:
This method is used to date rocks and minerals and is often used in conjunction with archaeology, especially when dealing with volcanic or igneous materials.
Fission Track Dating:
This method is used to date minerals and rocks by measuring the trails left by radioactive decay of Uranium in the past.

https://crowcanyon.org/education/learn-about-archaeology/archaeolog...

Part 1.

• ‹ Previous
• 1
• …
• 49
• 50
• 51
• 52
• 53
• …
• 1082
• Next ›
• Page