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Comment by Dr. Krishna Kumari Challa 3 hours ago

What happens when someone's chromosomes, sex hormones and body don't align?
Differences of sex development arise when chromosomes, gonads, hormone production, or hormone responsiveness diverge from typical pathways. Conditions such as congenital adrenal hyperplasia, androgen insensitivity, 5-alpha-reductase deficiency, and sex-chromosome variations can affect anatomy, puberty, fertility, and health. Individualized specialist care, clear information, and psychological support are important.

original article.

Comment by Dr. Krishna Kumari Challa 3 hours ago

What are chalk streams and why are these rare rivers under threat?
Chalk streams are groundwater-fed rivers with clear, cool, mineral-rich water and stable flows; seasonal headwaters called winterbournes support specialised aquatic and terrestrial species. Their biodiversity is threatened by water abstraction, pollution, channel modification, drought and heat. Reducing pollution and restoring natural flows can improve resilience.

Comment by Dr. Krishna Kumari Challa 4 hours ago

Our tissues carry a remarkably detailed record of the aging process.
By combining histology images with artificial intelligence, we can detect patterns of biological aging that are invisible to the human eye and begin to understand how aging unfolds differently across the body.
The analysis revealed that aging does not occur uniformly: Some tissues, such as the lung, kidney, pancreas and adrenal gland, showed signs of accelerated aging between the ages of 20 and 40. Others followed more complex trajectories, with peaks of accelerated aging appearing later in life. The uterus displayed a particularly striking shift around the age of menopause.

The researchers also identified strong links between tissue-specific aging and medical conditions or lifestyle-associated factors. For example, kidney failure was associated with accelerated aging signals in multiple tissues, while diabetes showed pronounced effects in the pancreas.

What stands out is how differently each organ ages, and how that shows up in tissue architecture.
Deep learning lets us read these spatial patterns, capturing aging as architectural remodelling, not just molecular drift. While the tissue clocks captured the normal pace of aging across organs, they also highlighted outliers—individuals whose tissues showed pronounced structural shifts ahead of their chronological age.
However, tissue samples cannot always be collected. By linking blood-based gene expression profiles with the histologically derived tissue age gaps of the same individuals, the researchers built predictors of tissue-specific biological age from blood samples alone.
These blood-based predictors successfully identified aging patterns linked to several diseases, including Alzheimer's disease, Crohn's disease, cystic fibrosis, vasculitis, diabetes and stroke. In Alzheimer's disease, for example, the strongest aging signal was detected specifically in the brain, whereas Crohn's disease showed accelerated aging across the gastrointestinal tract.

Histological aging signatures for monitoring tissue-specific aging and disease, Nature Medicine (2026). DOI: 10.1038/s41591-026-04566-5

Part 2

Comment by Dr. Krishna Kumari Challa 4 hours ago

Organs age at different speeds: A blood test might soon tell which ones

Some people seem to age more slowly than others, looking and acting like 45 at 60. Others appear to have gotten ahead of the calendar. But why is that, and what is actually happening inside the body?
AI-based "tissue clocks" can estimate the biological age of human organs from histological images, researchers showed. By analyzing more than 25,000 tissue samples across 40 tissue types, their study reveals that organs age at different rates throughout life and that these changes can even be detected from blood samples. The findings, published in Nature Medicine, provide a new framework for understanding aging and may open new avenues for disease monitoring and early diagnosis.
the researchers turned to the Genotype-Tissue Expression Project (GTEx), which collected tissue samples from 983 individuals across 40 different tissue types, ranging from the brain and heart to the lung, pancreas, skin and intestine. These were transformed into high-resolution digital images of tissue slices, each revealing the microscopic architecture of the organ in question. The scale is staggering: 25,712 images, representing about 480 million individual image tiles, analyzed with state-of-the-art vision models.

They found that the architecture of organs keeps a silent diary of time: Even without explicitly teaching the AI about it, age turned out to be the single strongest factor shaping tissue appearance across all 40 tissue types. Building on this, the research team developed so-called "tissue clocks"—predictive models that estimate a person's biological age from the appearance of their tissue, for each organ independently.

These clocks achieved a mean prediction error of just 4.9 years and outperformed existing DNA-based aging estimates in capturing tissue-specific pathology. Importantly, the predicted biological age was strongly linked to known hallmarks of aging, including telomere shortening, tissue pathology and the number of chronic diseases an individual had.
Part 1

Comment by Dr. Krishna Kumari Challa 4 hours ago

Cells use a little-known molecule to protect themselves from iron overload

Iron is essential. Our cells need it to produce energy, carry oxygen throughout the body and power countless chemical reactions that sustain life. But this metal has a dark side. When too much of it is left free inside cells, it can trigger destructive reactions that break down DNA, proteins and even cell membranes.
Now researchers have discovered that cells rely on an unexpected protector against this threat: small molecules called polyamines.

The researchers' detailed findings, published in the journal Cell, reveal that polyamines act like storage lockers for iron, safely holding the metal in a nonreactive state until cells need it.
These findings solve a decades-old mystery about why cells maintain such extraordinarily high levels of polyamines and uncover a previously unknown defense mechanism that protects cells from toxic iron overload.

This work could also help scientists develop better cancer treatments by allowing iron overload to trigger cancer cell death. It could also offer new clues about diseases like early-onset Parkinson's disease, in which mutations affect polyamine levels within neurons.

Polyamines buffer labile iron to suppress ferroptosis, Cell (2026). DOI: 10.1016/j.cell.2026.07.040. www.cell.com/cell/fulltext/S0092-8674(26)00872-X

Comment by Dr. Krishna Kumari Challa 4 hours ago

As the mice were learning this behavioral task, the researchers recorded their brain activity using miniaturized microendoscopes. These are ultrathin, lightweight imaging devices that can measure activity in hundreds of neurons simultaneously. The team observed activation patterns in the orbitofrontal cortex (OFC), a brain region involved in evaluating decisions guided by reward value.
The researchers chose to look at the orbitofrontal cortex because it has been shown to represent the value of options when humans and other animals are making decisions and previous experiments using mice had shown that it represents reward value that is signaled by odors in particular.
To understand how the brain represents the prospect of obtaining information, the researchers compared cases in which, based on the odor they sniffed, the mice expected to receive information with trials in which the reward outcome would remain unknown.

They identified a representation of the predicted value of information in the mouse orbitofrontal cortex.
Approximately 20% of the cells in the OFC showed different neural activity in response to odors that predicted information versus those that predicted no information, and the magnitude of that activity difference scaled with the duration of time the mice had knowledge of the reward outcome. This indicates that they identified a representation of information value that depended on its resolution of uncertainty, which is intrinsic to information and cognition.
The team's findings suggest that the mouse brain processes a desire for knowledge and the drive for physiological rewards differently.

The representation of the predicted value of information was discernible across the neural population in a way that was orthogonal to the representation of the predicted water value, which they observed in response to separate odors in their experiments. Given that they observed this pattern in the OFC, a brain area intimately involved in generating representations of the world to guide decisions, the representation of information value could be a critical signal that allows animals to take actions to gain information and increase their knowledge of the world.
The researchers pursued neural processes underlying curiosity and the drive to seek knowledge, with the goal that their work will also be applicable to humans.
Understanding how we evaluate sources of information and how wanting to gain knowledge drives our behaviour would have important implications for helping people navigate our information-rich modern world, including through learning during childhood development.
Not only could a better understanding of curiosity, the drive to gain information, improve people's success in learning, given the pleasurable, rewarding nature of acquiring knowledge, it could offer us access to more joy and fulfillment—something we all could use.

Jennifer J. Bussell et al, Representations of the intrinsic value of information in mouse orbitofrontal cortex, Nature Neuroscience (2026). DOI: 10.1038/s41593-026-02377-y.

Part 2

Comment by Dr. Krishna Kumari Challa 4 hours ago

Curiosity has its own neural signal: Brain separates valuable information from water rewards in mice
Often, humans and other animals seek information that can help them complete tasks and attain desired rewards. In some cases, however, they seek information driven simply by curiosity and a desire to obtain knowledge for its own sake, even if it does not lead to external rewards. Scientists know this better.
Researchers recently created a new experimental paradigm for studying the neural processes associated with curiosity and the desire for knowledge in mice. This paradigm, outlined in a paper in Nature Neuroscience, allowed them to gain new insights into how the brain represents the value of information regardless of physical rewards.
Previous studies offered some initial clues about how the mammalian brain attributes value to information. However, the process through which it recognizes stimuli that can provide interesting information and represents their value has not yet been elucidated.

This is a higher-order process of cognition, since what is most valuable as information depends on what we already know, and we can't detect and know how good information is by physiological processes in our body, the way we can with food or many other better understood types of reward that motivate our actions.
Researchers offered thirsty mice the choice of poking their noses into two holes.
One hole revealed with a short puff of odor whether they would receive a water reward, and the other revealed nothing but, critically, offered them the exact same chance and amount of water. Prior to making their decision, the mice had to poke in a third hole that presented them with an odor that either directed them to the information- or non-information-providing hole or offered them the choice. In this way, the mice learned that individual odors each predicted a certain amount of information or water reward.
Interestingly, the researchers observed that the mice predominantly preferred poking their noses into the hole that gave them information. This occurred even if the information-providing hole contained less water than the other hole. These findings suggest that mice are often willing to exchange water (i.e., a reward) for information. This, in turn, implies that the mice attribute value to the information itself.
Part 1

Comment by Dr. Krishna Kumari Challa 5 hours ago

AI agents struggle to perform original scientific research

Among the many predictions about the future of artificial intelligence is that models will one day be able to conduct scientific research on their own, leaving humans out of the equation. Already, they can write code, run experiments and search scientific literature, but carrying out open-ended research would require a significant leap in ability.
In a paper posted on the arXiv preprint server, researchers tested AI's ability to conduct open-ended research and found that it came up short.
The study authors gave frontier agents (cutting-edge, state-of-the-art AI tools designed to carry out complex, multi-step tasks autonomously) six days to conduct research and write papers based on two then-unpublished AI conference submissions. This ensured they couldn't just find the answers online.

The agents had full access to the internet, dedicated computing power and approximately $3,000 in model-use credits, meaning they had a budget to conduct open-ended exploration and run experiments. The topics they had to research and write about were the structure and controllability of language-model personas and designing a detector for distribution shifts in tabular foundation models.

Once the six days were up, human researchers reviewed the AI-written papers and graded them as they would papers submitted to a top-tier AI conference.

The frontier agents did not do well at all. Both papers received unambiguous rejection scores (2/6 and 1/6 overall) from the expert human reviewers. Although the AI understood the research questions and proposed some directions that closely mirrored those of the original researchers, its scientific reasoning suffered from major flaws. Experimental designs were weak, and the agents handled negative feedback poorly, often adding caveats to existing findings rather than redesigning their studies.

They also managed their time poorly and spent less than half of their allocated API budget. Despite having time, they rushed through their work and submitted papers that fell far short of publishable standards.

The reviewers did not hold back on their assessments of the agents:

"The experiments and methodological choices were bizarre and hard to understand. The results seem clearly a result of post hoc choices."—David Africa, expert reviewer.
"Upon testing a few unsuccessful signals using a PFN's internals, going from there to 'there are no signals we can use that leverage a model's internals' is a huge leap, a kind of 'proof by example' fallacy that is highly non-scientific."—Viet Nguyen, expert reviewer.
While these results are a sobering reality check on AI's ability to perform scientific research, they do not mean models have no place in the lab. In the near term, they are more likely to serve as assistants handling routine tasks rather than being deeply involved in the process of discovery.

Peter Kirgis et al, Can AI agents conduct open-ended AI research? Early evidence from two case studies, arXiv (2026). DOI: 10.48550/arxiv.2607.27191

Comment by Dr. Krishna Kumari Challa yesterday

Fridge-free vaccines

Scientists have successfully trialled vaccines that do not need to be refrigerated or frozen, which could slash the number of vaccine doses that are wasted each year. Sixty volunteers received a tetanus-diphtheria vaccine that had been kept as a dry powder for a year at room temperature before it was dissolved and injected. The jab was “safe and well tolerated” and gave “equivalent” immune responses to the conventional vaccine. The team will launch a larger trial of 160 people in the coming months.

https://www.thelancet.com/journals/eclinm/article/PIIS2589-5370(26)00369-X/fulltext?utm_source=Live+Audience&utm_campaign=e2b449d6f7-nature-briefing-translational-research-20260812&utm_medium=email&utm_term=0_-928f7c52f0-50323416

Comment by Dr. Krishna Kumari Challa yesterday

Fungal age remains elusive as underground networks continually grow, split and recycle
Fungal age is difficult to define because mycelial networks continually grow, recycle tissue and fragment into genetically identical units. Longevity likely varies among species and lifestyles, requiring genetic tracking, long-term experiments and microfluidic systems to characterize persistence and life cycles.

Exploring the concept of longevity in fungi, Trends in Microbiology (2026). DOI: 10.1016/j.tim.2026.07.001

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