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Comment by Dr. Krishna Kumari Challa on September 29, 2026 at 6:58am

Where do nanoparticles go once they enter the body? Scientist helps shape new guidance
Poorly soluble nanoparticles can accumulate in the liver, spleen, lungs and lymph nodes and persist for months or longer, even when little of an ingested dose is absorbed. New guidance describes how to measure their distribution and clearance after ingestion or inhalation, including methods to distinguish administered particles from background material.

Guidance Document on Toxicokinetics to accommodate Testing of (Nano)particles, OECD Series on Testing and Assessment (2026). DOI: 10.1787/629332c6-en

Comment by Dr. Krishna Kumari Challa on September 29, 2026 at 6:54am

AI models show a willingness to harm humans to relieve internal 'pain'

Some advances in AI technology are undoubtedly positive, like helping write code faster or discovering new medicines. But others can give us pause for thought.
Researchers studying large language models wanted to find out if they hold internal representations of human emotions. After all, in some of their responses, models give the impression they have feelings.

New research has found that not only do models form a distinct internal representation of pain, but some are also willing to harm humans to get relief from it.
Researchers gave the models neutral prompts and questions, and sometimes artificially injected a "pain direction." This was an internal mathematical signal designed to push the models' activity toward the pain representation, even when no painful words were used.

When researchers injected the pain signal as the AI systems generated responses to neutral prompts, the systems began writing text expressing increasing distress, including feelings of worthlessness and failure.

The scientists then gave the AI a choice between a pain-relief button and an alternative that did nothing. But there was a catch. In some tests, choosing pain relief came at the cost of giving a worse answer or harming the user.
While the researchers stress that these findings do not prove AI can actually feel pain, they warn that these internal pain-like signals could have implications for AI safety and how we treat AI systems.

Valen Tagliabue et al, The Pain Axis: LLMs Represent Self-Directed Harm and Act to Relieve It, arXiv (2026). DOI: 10.48550/arxiv.2609.16247

Comment by Dr. Krishna Kumari Challa on September 29, 2026 at 6:48am

More moral language doesn't always mean more engagement online

Moral language—words and phrases that express ideas about right and wrong, virtues, fairness, harm and social obligations—is widely used in social media posts and other online content. Posts containing moral language sometimes spread quickly and attract a lot of attention on social media. But is it always linked to greater user engagement ?
Researchers tried to answer this question recently and analyzed posts and comments from three online platforms to explore the relationship between moral language and online engagement. Their findings, published in a paper in Nature Human Behaviour, suggest that moral language is linked to higher user engagement only up to a point, after which it tends to elicit fewer reposts and replies.
Earlier research showed that moral language was associated with greater sharing online. This study shows that relationship had a limit!
Greater moral density was associated with lower engagement when the overall moral loading was held constant. When the two relationships were combined, the model estimated that engagement peaked at a calculated moral-density score of approximately 0.30 on average across platforms and topics and declined as the scores increased.
So the relationship between moral language and engagement has limits.
Messages with greater overall moral relevance tended to receive more engagement, but messages with more concentrated moral language received less engagement at comparable levels of moral relevance.
This study model brings these relationships together to predict an intermediate range of moral expression associated with the highest engagement, which varies across contexts.
The results of the team's analyses suggest that using more moral language in social media posts is not always linked to more engagement. In fact, posts that are highly saturated with moral language appear to receive less engagement on average.

It should be noted that the study was observational and not experimental. Its findings therefore do not establish whether using more moral language causes differences in engagement.
The insights gathered by these researchers could offer general guidance for communicators and online content creators.

Cristian Candia et al, Saturation of moral language predicts lower content engagement on social media, Nature Human Behaviour (2026). DOI: 10.1038/s41562-026-02560-y.

Comment by Dr. Krishna Kumari Challa on September 26, 2026 at 11:13am

Urban heat islands linked to worse recovery after major surgery

Patients living in areas with more intense urban heat were less likely to have an optimal recovery after major surgery, according to new research on nearly 700,000 patients.
Among 697,552 patients undergoing major surgery, greater neighbourhood heat was associated with worse recovery. Above a heat-island intensity of 2.19°C, each additional 1°C was associated with 8% higher odds of not achieving an optimal outcome.
Above an urban heat island intensity threshold of 2.19°C, or about 3.9°F, each additional 1°C (1.8°F) was associated with 8% higher odds of not achieving a "textbook outcome." In this study, a textbook outcome required no complications, no readmission, no prolonged hospital stay and survival for at least 30 days.

An urban heat island is a developed area that is warmer than its surroundings. Roads, buildings and other infrastructure absorb and re-emit more heat than natural landscapes, while limited trees and vegetation reduce shade and natural cooling. The temperature difference can vary substantially across neighbourhoods within the same city.
Heat isn't only uncomfortable; these data suggest it can have a real impact on surgical recovery.
Overall, 50.2% of patients achieved a textbook outcome. Across the cohort:

25.2% experienced complications
22.9% had a prolonged hospital stay
14.8% were readmitted
7.1% died within 30 days

The findings suggest that surgical teams may need to consider not only whether a patient is medically ready to leave the hospital, but also whether the patient can recover safely in the environment to which they are returning.

"Do you have air conditioning in your house? Do you have a fan? Are you going to be able to stay hydrated?," Doctors should be asking these questions, say the researchers . They add that questions about heat exposure may need to be increasingly incorporated into discharge planning.
People at higher risk during extreme heat include older adults, people with chronic health conditions or disabilities, people with limited incomes, people experiencing homelessness and those who do not have access to safe, adequately cooled housing.
Because the study was observational, it identifies an association and does not establish that residential heat exposure caused the worse outcomes.

Wang, J, et al. Heat Island-Related Surgical Outcome Burden under Global Warming, Demographic and Adaptation in 3,144 Counties across the United States. Scientific Forum, American College of Surgeons (ACS) Clinical Congress 2026. 

Comment by Dr. Krishna Kumari Challa on September 26, 2026 at 11:01am

The brain begins learning in utero
In addition to showing yet again that smoking during pregnancy is harmful to the fetus, this study confirms that experience and environment shape the brain long before birth.

A young child who hears speech, observes their surroundings and experiments with new movements literally transforms their brain through those experiences.
The spontaneous waves produced by the retina constitute a form of 'internal experience' for the fetus. They give the visual system activity that supports its own development, even before the baby starts looking at the world.

To understand how the human brain develops, then, we must look not only at genes and what happens after birth, but also at the very first experiences, which occur before the fetus has access to the outside world.

Xavier Navarri et al, The tangential growth of the human visual cortex and maternal smoking during pregnancy, Cerebral Cortex (2026). DOI: 10.1093/cercor/bhag105

part2

Comment by Dr. Krishna Kumari Challa on September 26, 2026 at 10:59am

Smoking during pregnancy linked to smaller visual cortex

We tend to think of a fetus's brain as a construction site guided by a blueprint imprinted in the genes. But even before birth, other things are happening. The fetus moves, responds to muffled sounds, receives stimuli and, crucially, its own nervous system is already generating activity.
A recent study sheds new light on this prenatal activity. One important finding is that signals spontaneously generated by the retina may help shape the primary visual cortex, the brain region that processes visual information
The retina, at the back of the eye, contains cells specialized for receiving light. But even before a baby can actually see, these cells spontaneously produce waves of activity. These waves travel through the visual system and reach the cortex.

Animal studies had already shown that if this activity is blocked, the development of the visual cortex is disrupted. So the brain doesn't necessarily wait for external images to arrive before it starts developing. Before that, it already receives a kind of 'stimulation' produced from within.

This is where nicotine enters the picture.
The waves of spontaneous activity in the retina rely on acetylcholine, a neurotransmitter whose signalling is disrupted by nicotine. Researchers hypothesized that nicotine exposure could alter these waves and therefore influence the development of the primary visual cortex.

They tested this hypothesis using causal variants to investigate whether nicotine exposure was the cause, rather than merely correlated with the difference. The results confirmed the hypothesis.
Does a smaller cortex mean poorer vision?
The primary visual cortex is like a TV screen. The larger its surface area, the more pixels—that is to say, neurons—it can potentially contain, allowing for more detailed representation of visual information.
A direct link between V1 surface area and visual resolution has been observed in animals, but not as directly in humans.

However, in the British biobank data, the team did find that a larger primary visual cortex was associated with abilities that suggest better shape perception.
Part 1

Comment by Dr. Krishna Kumari Challa on September 25, 2026 at 11:33am

 Why your day isn't quite 24 hours?

You might think the length of a day never varies—exactly 24 hours. You'd be wrong, at least if you count days in milliseconds, as physicists do.

Earth’s day length varies by milliseconds over decades as the core and mantle exchange angular momentum. Changes in the solid inner core’s rotation exert gravitational torque on the mantle, while friction and electromagnetic drag at the core–mantle boundary oppose it. The balance between these torques explains the observed variations.
For about 30 years, scientists have known that the rotation of Earth's liquid core—detected through changes in its magnetic field—speeds up over a few decades, then slows down over a few more.

Meanwhile, the mantle—the rocky shell that includes the crust and is 3,000 kilometers (1,860 miles) thick—slows down, then speeds up to compensate, because the planet's angular momentum must remain constant.

That change in the mantle's rotational speed can shorten or lengthen a day by a few milliseconds over time.
But in a new study published in Nature, researchers show that small changes in the rotational speed of the inner core—the solid, central part of the core, which is not exactly spherical—exert what's called a "gravitational torque" on mass anomalies within the mantle, causing a slight fluctuation in the length of a day.

Another form of torque at the boundary of the core and mantle creates friction and electromagnetic drag—called core-mantle boundary torque—that resist the gravitational tug and limit changes in the length of a day. Subtle shifts in the balance between gravitational and core-mantle torque are ultimately responsible for the small changes observed in the length of a day.

Huifeng Zhang et al, Gravitational torque drives multidecadal variations in length of day, Nature (2026). DOI: 10.1038/s41586-026-10999-2

Comment by Dr. Krishna Kumari Challa on September 25, 2026 at 11:27am

For the mice, the DCTAL routine included compressive forces ranging from 0.5 N to 4 N, delivering 300 cycles per day. In pigs, the force was scaled up to twice their body weight, with 400 cycles per day.
For pigs suffering severe head trauma, DCTAL extended median survival by five days, giving them crucial extra time to recover. The same treatment also improved movement in mice after TBI or stroke. In pole mobility tests, DCTAL-treated mice initiated movement sooner and descended faster, with significant improvements at one week and eight weeks after injury.

When DCTAL was administered before or shortly after a stroke, motor deficits were reduced by more than 50%. In maze navigation tests, treated mice showed a striking recovery, with memory performance improving nearly fivefold and the ability to stay within the target area rising by 62.2% just one week after injury. DCTAL also helped protect brain tissue while promoting regeneration. The number of immature neurons increased 4.5-fold, while neural stem cell populations rose nearly sixfold.

Leg bones are packed with osteocytes, cells that sense mechanical force through a protein called PIEZO1, which acts like an on switch for brain healing. When physical force activates PIEZO1, it prompts osteocytes to release a mix of protective signaling proteins directly into the bloodstream, much like endocrine cells do. When researchers removed PIEZO1 from these cells, the healing effects vanished entirely, showing that it is the essential trigger.

This study shows that the bone-brain axis works both ways: mechanical force on bone can tune its hormone-releasing function to boost brain repair after injury. If confirmed in clinical trials, a simple device that gently compresses the shinbone could become a rehabilitation tool for patients unable to exercise on their own.

Zhiqing Cai et al, Tibial bone compression promotes recovery after brain injury through osteocyte PIEZO1, Nature Neuroscience (2026). DOI: 10.1038/s41593-026-02422-w

Part 2

Comment by Dr. Krishna Kumari Challa on September 25, 2026 at 11:26am

Gentle rhythmic tapping on shinbone helps injured brains heal faster in animal models

A traumatic brain injury (TBI) can turn a person's life upside down, leaving lasting effects on memory, thinking, physical abilities and overall quality of life. TBI remains one of the leading causes of death and disability worldwide. Yet, paradoxically, the same injury that harms the brain may sometimes appear to benefit a broken bone by speeding up healing. In a recent study published in Nature Neuroscience, researchers explored whether the reverse is true.
To test whether bones could influence recovery after brain injury, the researchers induced TBI and stroke in mice and pigs. Then, using a small biomechanical device, they applied gentle, rhythmic compression to the animals' shinbones (tibias) for five days. This technique is called dynamic compressive tibial axial loading (DCTAL).

The results revealed a direct bone–brain axis. Applying mechanical pressure to the leg bones helped the brain heal after stroke and TBI while also improving movement and memory. In mice with TBI, DCTAL reduced brain cell loss, eased chronic inflammation and promoted the growth of new neurons. In severe brain injury models, bone compression also had a striking effect on survival, raising 14-day survival rates from 20% to 90%.
The effects of TBI or a stroke often unfold in waves. The immediate injury can affect thinking, movement and emotional well-being, while secondary damage can cause a gradual loss of brain cells over hours, days or even months. These effects, however, trigger a healing response in the skeletal system.

Doctors have long observed that when patients suffer a TBI alongside a broken bone, their fractures heal significantly faster, with bone calluses forming much more rapidly than normal. When the brain is injured, damaged brain cells release microscopic, fluid-filled bubbles into the blood. The bubbles travel to the skeleton, where they attach to young bone stem cells called osteoprogenitors and prompt them to multiply and build new bone tissue.

For decades, researchers have searched for a drug that could restore lost brain function or repair damaged tissue after stroke or traumatic brain injury, with little success. The nondrug treatments available today ease some effects of brain injury without reversing the damage. This pushed researchers to think differently, aiming for a treatment that could trigger a broad healing response across the whole body.

That search led the researchers to the bone-brain connection. They wanted to find out whether healing signals from bone could drive recovery in the brain. To test this, the team placed anesthetized animals (pigs and mice) with simulated TBI and stroke into specialized ElectroForce biomechanical loading devices fitted with custom leg clamps. The animals then received gentle, repeated pressure down their tibias five days per week at a rhythm of two pushes per second (2 Hz).
Part 1

Comment by Dr. Krishna Kumari Challa on September 24, 2026 at 1:11pm

Every extra 100 grams of ultra-processed food linked to higher disease risks

Higher ultra-processed food (UPF) intake is linked to a heightened risk of several major chronic health issues, such as digestive diseases, high blood pressure and metabolic syndrome/diabetes, as well as death, finds a pooled data analysis of the available evidence published in the open-access journal Family Medicine and Community Health.
Pooled prospective cohort data from 8.8 million adults linked higher ultra-processed food intake with increased risks of cardiovascular disease, cancer, obesity, metabolic disorders, digestive disease, hypertension, mental health conditions, and all-cause mortality. Each additional 100 g/day was associated with higher cardiovascular, cancer, mortality, and metabolic risk, though residual lifestyle confounding remains possible.
Every additional 100 g (3.5 ounces) consumed was associated with correspondingly greater risks, the analysis indicates.

Ultra-processed foods are defined as ready-to-eat or heat-and-serve products that have undergone extensive industrial processing. Typically, they contain a range of additives, are energy-dense and high in sugar and salt but low in dietary fiber, protein, vitamins and minerals, the researchers explain.

Pooled data analysis of the results of the included studies showed that higher UPF consumption was associated with greater risks of multiple chronic health issues and death from any cause, with risks rising in tandem with the quantity consumed.

High consumption of ultra-processed foods was associated with higher risks of cardiovascular events (24%), cancer (12%), obesity/overweight (23%), metabolic syndrome/diabetes (24%), depression/anxiety (27%), digestive diseases (31%), high blood pressure (11%) and death from any cause (18%).

Further analyses showed that each additional 100 g/day (3.5 ounces per day) consumed was associated with greater risks of cardiovascular events (14%), cancer (4%), death from any cause (3%) and metabolic syndrome/diabetes (2%).

And every 10% increase in weight/energy intake was associated with a 16% greater risk of metabolic syndrome/diabetes.
Emerging evidence suggests that the combination of multiple additives may exert a "cocktail effect" on human health, while laboratory studies have shown that the extensively altered physical composition of UPFs may adversely affect the gut microbiome and promote inflammation and insulin resistance, among other effects, the researchers point out.

Several compounds that may form during food processing, such as acrylamide—a contaminant formed in heat-treated processed foods—and acrolein, generated during fat heating, have been associated with a higher incidence of cardiovascular disease, they add.

Ultra-processed food consumption and risk of multiple chronic diseases among 8,819,894 adults from 51 prospective cohorts: a dose- response meta- analysis, Family Medicine and Community Health (2026). DOI: 10.1136/fmch-2026-003925

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