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Comment by Dr. Krishna Kumari Challa yesterday

Seafood unfairly singled out in microplastics debate, researchers say

Seafood has received disproportionate attention in media coverage about microplastics, despite evidence that fish and shellfish are not the main source of human exposure, according to a new scientific review.

Researchers found that more than 70% of scientific and media coverage on microplastics in food has focused on seafood, contributing to the public perception that eating fish is the biggest risk.

This misperception has real consequences, as some consumers report reducing consumption of seafood because of concerns over microplastics exposure, and thereby miss out on the health benefits of seafood consumption. The findings are reported in the journal Environmental Science & Technology Letters.

In reality, people are far more exposed to microplastics from indoor air and dust.

A previous study reported that the presence of microplastics in mussels collected from the environment was lower than the amount of microplastics that falls on a plate of mussels during dinner time in a typical household.

Seafood, including mussels and oysters and finfish like salmon and cod, may contribute 1–10 microplastic particles per day, which is consistent with other foods, like salt, honey and chicken.

Ingestion from bottled water is estimated at 10 to 100 particles per day, and exposure from indoor air accounts for considerably higher exposure—100 to 1,000 particles per day.

There is minimal evidence that they pose a health risk. The evidence we do have indicates that plastic particles readily pass through the digestive tract and exit the body.

While there are perceptions that toxic substances associated with plastic particles may pose health risks, evidence indicates concentrations are actually exceedingly low compared to other sources of exposure.

Theodore B. Henry et al, Examining Misconceptions about Plastic-Particle Exposure from Ingestion of Seafood and Risk to Human Health, Environmental Science & Technology Letters (2025). DOI: 10.1021/acs.estlett.5c00551

Comment by Dr. Krishna Kumari Challa yesterday

Rare Earth Elements: 17 Minerals More Valuable Than Gold in Today’s Tech World

Comment by Dr. Krishna Kumari Challa yesterday

Enrollment involved 198 adults at two academic cardiac surgery centers in Germany, all undergoing first-time isolated CABG for three-vessel or left main disease, without prior arrhythmias, monitored for one year after implant of a device during surgery.

Patients were followed through continuous rhythm surveillance using an insertable cardiac monitor placed at skin closure. AF was defined as device-detected and adjudicated episodes lasting at least two minutes.

Within one year, 95 of 198 patients developed new-onset AF, yielding a cumulative incidence of 48% with a 95% CI of 41%–55%. Standard monitoring identified a 34% cumulative incidence with a 95% CI of 27%–41% and Gray's test P = .01 versus continuous monitoring. Sensitivity analyses using longer episode thresholds produced cumulative incidences of 46% at four minutes, 45% at six minutes, and 44% at 12 minutes.

Across the cohort with new-onset AF, median AF burden over the first year measured 0.07%, corresponding to 370 minutes. Early postoperative days carried the most arrhythmia time, with median burden of 3.65% on days 1–7, 0.04% on days 8–30, and 0% on days 31–365. A total of 2,053 episodes, accounting for 2,522 hours, were recorded, with a median episode length of six minutes and a median time-to-incident episode of 3.3 days. Asymptomatic presentations comprised 63% of episodes, and 67% were not captured by standard monitoring.

Among 95 patients with AF, 73 patients had incident episodes within seven days and 90 within 30 days, and 45% of accumulated AF time occurred within the first seven days and 77% within 30 days.

Recurrent AF later than 30 days appeared in 19 of 90 patients with incident episodes prior to 30 days, totaling 554 episodes with a median length of four minutes. Asymptomatic recurrences comprised 43% of these later episodes, and 3% were detected by standard monitoring.

The authors conclude that continuous monitoring uncovers substantially more AF than standard surveillance, while measured burden remains very low after 30 days.
Their findings question routine long-term oral anticoagulation after new-onset AF following CABG and support reassessment at 30 days when treatment is initiated.

Florian E. M. Herrmann et al, Long-Term Continuous Monitoring of New-Onset Atrial Fibrillation After Coronary Artery Bypass Grafting, JAMA (2025). DOI: 10.1001/jama.2025.14891

Gregory M. Marcus, Is There Really Something Different About Postoperative Atrial Fibrillation After Cardiac Surgery?, JAMA (2025). DOI: 10.1001/jama.2025.15275

Part 2

Comment by Dr. Krishna Kumari Challa yesterday

Atrial fibrillation after bypass found in nearly half of patients

Investigators  report a higher-than-expected one-year incidence of new-onset atrial fibrillation after coronary artery bypass grafting, paired with very low burden beyond 30 days.

Postoperative atrial fibrillation (AF) ranks among the most frequent early complications after cardiac surgery with reported incidence near 30%, tying into longer hospital stays, higher costs, discomfort, and observational links to thromboembolic stroke, heart failure, and recurrence.

North American guidelines state that 60 days of oral anticoagulation is reasonable with later reassessment, and European guidance advises that long-term anticoagulation should be considered in patients with new-onset AF after cardiac surgery.

Previous large cohort studies leaned on brief in-hospital telemetry and intermittent checks after discharge, leaving incidence, burden, and recurrence insufficiently characterized and prompting calls for long-term continuous monitoring.

In the study, "Long-Term Continuous Monitoring of New-Onset Atrial Fibrillation After Coronary Artery Bypass Grafting," published in JAMA, researchers conducted a prospective multicenter cohort study to test whether one-year AF incidence after coronary artery bypass grafting (CABG) exceeds prior literature and to assess AF burden.

Part 1

Comment by Dr. Krishna Kumari Challa yesterday

DNA repair mechanisms help explain why naked mole-rats live a long life

Naked mole-rats are one of nature's most extraordinary creatures. These burrowing rodents can live for up to 37 years, around ten times longer than relatives of a similar size. But what is the secret to their extreme longevity? How are they able to delay the decay and decline that befalls other rodents? The answer, at least in part, is due to a switch in a common protein that boosts DNA repair, according to new research published in the journal Science.

One of the main causes of aging in all animals, including humans, is the accumulation of damaged DNA, our genetic instruction manual. When this damage is not fixed, it leads to defective cells, damaged proteins and eventually a breakdown in the body's functions.

To understand how the naked mole-rat is so resistant to DNA damage, a study focused on a common protein called cGAS (cyclic GMP-AMP synthase). In most mammals, cGAS interferes with DNA repair, but the researchers suspected it may have evolved a different function in the long-living rats.

Researchers compared the cGAS protein in naked mole-rats to that of humans and mice and identified four changes in amino acids (building blocks of cGAS) that flip the protein's function so that it enhances a cell's ability to repair damaged DNA.

To test this, the scientists inserted the mole-rat's unique cGAS into human and mouse cells in the lab. The result was a significant boost in the cells' ability to repair their DNA and a reduction in cellular aging. Then, they engineered fruit flies to produce naked mole-rat cGAS and found that they lived around ten days longer than a control group of fruit flies that couldn't produce cGAS. Finally, they used gene therapy to give the naked mole-rat cGAS to mice. These treated rodents were less frail, had less gray hair and there were fewer old, worn out cells in different organs than mice that didn't receive the gene.

"This alteration confers naked mole-rat cGAS with a greater capacity to stabilize the genome, counteract cellular senescence   and organ aging, and promote extended life span and health span," commented the researchers.

Yu Chen et al, A cGAS-mediated mechanism in naked mole-rats potentiates DNA repair and delays aging, Science (2025). DOI: 10.1126/science.adp5056

Comment by Dr. Krishna Kumari Challa yesterday

Living in an unequal society impacts the structure of children's brains, study finds

The distribution of wealth between different people living in specific geographical regions has changed substantially over the past decades, with some segments of the population benefiting most from economic growth than others. In some parts of the United States, the United Kingdom and various European countries, the distribution of wealth has become increasingly uneven.

An uneven wealth distribution essentially means that there is significant disparity in the income and resources of the general population, with some people earning good salaries and others living in the same place struggling to meet their basic needs. This inequality is typically measured with a value ranging from 0 to 1, known as the Gini coefficient, where 0 represents perfect equality and 1 extreme inequality.

Researchers  recently carried out a study aimed at exploring the possible impact of living in a society where wealth is unevenly distributed on the brain's development in late childhood and pre-adolescence. Their findings, published in Nature Mental Health, suggest that living in places with a high income inequality is associated with differences in the structure of some brain regions, which could in turn predict the emergence of mental health disorders.

As part of their study, the researchers analyzed data from the ABCD dataset, which was collected from over 8,000 9–10-year-old children living across 17 U.S. states, along with Gini coefficients for these states. The data they analyzed included magnetic resonance imaging (MRI) scans showing the thickness, surface area and volume of specific regions of the children's brain, as well as functional magnetic resonance imaging (fMRI) scans showing the connections between 12 key regions in their brains.

In their analyses, the researchers controlled for other factors that might be influencing the development of the children's brains, such as their family's income, education, health care access and incarceration rates in their home state. In addition, they looked at the children's reported mental health 18 months after the brain scans were collected.

The results of the analyses  suggest that living in an unequal society is associated with a thinner cortex (i.e., the brain's outer layer), as well as significant differences in the surface area of various brain regions. In addition, the communication between some brain networks appeared to be altered in children living in places marked by higher income inequality.

The differences observed by the researchers could partly explain the relationship they found between state-wide inequality and children's mental health, particularly the emergence of disorders in children living in unequal environments.

 Divyangana Rakesh et al, Macroeconomic income inequality, brain structure and function, and mental health, Nature Mental Health (2025). DOI: 10.1038/s44220-025-00508-1.

Comment by Dr. Krishna Kumari Challa on Monday

Women Have Twice as Many Depression Genes as Men, Says  Study

Women are genetically at higher risk of clinical depression than men, Australian researchers found in a study published last week that could change how the disorder is treated.
Billed as one of the largest-ever studies of its kind, scientists pored through the DNA of almost 200,000 people with depression to pinpoint shared genetic "flags".

Women had almost twice as many of these genetic markers linked to depression as men, according to the study.
The genetic component to depression is larger in females compared to males. Around 13,000 genetic markers were linked with depression in women, the researchers found, compared with 7,000 markers in men.

Some of these genetic changes could alter biological pathways linked to metabolism or hormone production.

https://www.nature.com/articles/s41467-025-63236-1

Comment by Dr. Krishna Kumari Challa on Monday

Chaos tamed by thermodynamics : Nonlinear multimode optical systems are often dismissed as chaotic and unpredictable. Their intricate interplay of modes has made them among the hardest systems to simulate—let alone design for practical use. Yet, precisely because they are not constrained by the rules of linear optics, they harbor rich and unexplored physical phenomena.

Recognizing that light in these systems undergoes a process akin to reaching thermal equilibrium—similar to how gases reach equilibrium through molecular collisions—the researchers developed a comprehensive theory of "optical thermodynamics." This framework captures how light behaves in nonlinear lattices using analogs of familiar thermodynamic processes such as expansion, compression, and even phase transitions.
The team's demonstration in Nature Photonics marks the first device designed with this new theory. Rather than actively steering the signal, the system is engineered so that the light routes itself.

The principle is directly inspired by thermodynamics. Just as a gas undergoing what's known as a Joule-Thomson expansion redistributes its pressure and temperature before naturally reaching thermal equilibrium, light in the new device experiences a two-step process: first an optical analog of expansion, then thermal equilibrium. The result is a self-organized flow of photons into the designated output channel—without any need for external switches.

Hediyeh M. Dinani et al, Universal routing of light via optical thermodynamics, Nature Photonics (2025). DOI: 10.1038/s41566-025-01756-4

Part 2

Comment by Dr. Krishna Kumari Challa on Monday

First device based on 'optical thermodynamics' can route light without switches

A team of researchers  has created a new breakthrough in photonics: the design of the first optical device that follows the emerging framework of optical thermodynamics.

The work, reported in Nature Photonics, introduces a fundamentally new way of routing light in nonlinear systems—meaning systems that do not require switches, external control, or digital addressing. Instead, light naturally finds its way through the device, guided by simple thermodynamic principles.

Universal routing is a familiar engineering concept. In mechanics, a manifold valve directs inputs to a chosen outlet. In digital electronics, a Wi-Fi router at home or an Ethernet switch in a data center directs information from many input channels to the correct output port, ensuring that each stream of data reaches its intended destination.

When it comes to light, the same problem is far more challenging, however. Conventional optical routers rely on complex arrays of switches and electronic control to toggle pathways. These approaches add technical difficulty, while limiting speed and performance.

The photonics team has now shown that there is another way. The idea can be likened to a marble maze that arranges itself.

Normally, you'd have to lift barriers and guide a marble step-by-step to make sure it reaches its destination—the right hole. In the team's device, however, the maze is built so that no matter where you drop the marble, it will roll on its own toward the right place—no guiding hands needed. And this is exactly how light behaves: it finds the correct path naturally, by following the principles of thermodynamics.

Party 1

Comment by Dr. Krishna Kumari Challa on Monday

Easter Island's statues actually 'walked,' and physics backs it up

For years, researchers have puzzled over how the ancient people of Rapa Nui did the seemingly impossible and moved their iconic moai statues. Using a combination of physics, 3D modeling and on-the-ground experiments, a research team has confirmed that the statues actually walked—with a little rope and remarkably few people.

Studying nearly 1,000 moai statues, they found that the people of Rapa Nui likely used rope and "walked" the giant statues in a zig-zag motion along carefully designed roads. The paper is published in the Journal of Archaeological Science.

They 

 had previously demonstrated via experimental evidence that the large statues "walked" from their quarry to ceremonial platforms using an upright, rocking motion, challenging a theory that the statues were moved lying prone on wooden devices.

"Once you get it moving, it isn't hard at all—people are pulling with one arm. It conserves energy, and it moves really quickly," they say.

The hard part is getting it rocking in the first place. The question is, if it's really large, what would it take? Are the things that we saw experimentally consistent with what we would expect from a physics perspective?"

To explore how a larger statue might move, the team created high-resolution 3D models of the moai and identified distinctive design features—wide D-shaped bases and a forward lean—that would make them more likely to be moved in a rocking, zig-zagging motion.

Putting their theory to the test, the team built a 4.35-ton replica moai with the distinct "forward-lean" design. With just 18 people, the team was able to transport the moai 100 meters in just 40 minutes, a marked improvement over previous vertical transport attempts.

The physics makes sense, say the researchers, "What we saw experimentally actually works. And as it gets bigger, it still works. All the attributes that we see about moving gigantic ones only get more and more consistent the bigger and bigger they get, because it becomes the only way you could move it."

Adding to the support for this theory are the roads of Rapa Nui. Measuring 4.5 meters wide with a concave cross-section, the roads were ideal for stabilizing the statues as they moved forward.

 Carl P. Lipo et al, The walking moai hypothesis: Archaeological evidence, experimental validation, and response to critics, Journal of Archaeological Science (2025). DOI: 10.1016/j.jas.2025.106383

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