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Comment by Dr. Krishna Kumari Challa 13 hours ago

Scientists Discover Strange 4-Stranded Genetic Structures in Human Blood

If you think you know what DNA looks like, there may be a surprise hiding in your blood.

DNA instantly brings to mind its famous double helix. But genetic material does not always remain in that familiar form. Some pieces can fold into compact, four-stranded structures.

These unusual shapes have previously been seen inside cells. Now scientists say they have caught them folded in human blood plasma.

So why is DNA in our blood at all?

As cells throughout the body die, they leave behind small fragments of DNA. These enter the bloodstream like pieces of a torn message, carrying clues about what is happening inside us.
Until now, scientists have concentrated on reading the message: its genetic letters, the length of each fragment, and where in the genome it came from. A new preprint study suggests that how the message is folded could matter too.

Researchers detected four-stranded structures called G-quadruplexes, or G4s, in genetic material captured directly from human plasma.

A G4 begins when four copies of the genetic letter guanine join to form a tiny square. Several squares can stack together, creating a compact structure very different from the familiar double helix.

The mystery began when scientists noticed unusual fragments known as ultrashort cell-free DNA. At roughly 50 genetic letters long, these single strands were so small that they could slip through the nets used by standard DNA-capturing methods.
Some contained enough guanine to form G4s, and computer analyses pointed to the same possibility.

But finding a piece of string that could form a knot is not the same as finding it already knotted. The team had to catch these structures in human blood while they were still folded.
The discovery opened another mystery.

Although the investigation began with ultrashort DNA, the experiment could not reveal whether the detected G4s were made from DNA or RNA. RNA can fold into the same four-stranded shape, and the detectors recognize the structure rather than the molecule underneath it.
Scientists also do not yet know which tissues released them, or whether the structures folded inside cells or only after entering the bloodstream.
G4s often occur in parts of the genome involved in controlling genes, and elevated G4 levels have been observed in several tumor types. This raises the possibility that G4s circulating in blood could one day provide information about cancer that cannot be found by reading DNA sequences alone.

https://www.biorxiv.org/content/10.64898/2026.09.05.747829v1

Comment by Dr. Krishna Kumari Challa 13 hours ago

Scientists Gave People BPA For 5 Days. Their Insulin Sensitivity Changed

A ubiquitous industrial chemical commonly used in food and beverage packaging may quietly mess with the body's insulin sensitivity when ingested.

Bisphenol A (BPA) is one of the highest-volume chemicals produced worldwide.

Since the 1960s, it has been used to manufacture an unfathomable number of plastic packages and epoxy resins, which coat the insides of many food and beverage cans.

By some estimates, BPA is so widely consumed that it is present in the urine of more than 90 percent of the US population.

But is that safe?

US health guidelines might say yes, but the first experimental evidence in humans has now found that ingesting BPA, even at low doses, may reduce insulin sensitivity in the short term.
Reducing BPA exposure, such as using stainless steel or glass bottles and BPA-free cans, may lower diabetes risk.

https://academic.oup.com/jcem/article/111/9/2610/8537216?login=false

Comment by Dr. Krishna Kumari Challa 14 hours ago

Driving through water is the biggest cause of death during floods—here's how it can happen
Driving through floodwater can cause vehicles to float, be swept downstream and overturn, creating a drowning risk. In a survey of 185 drivers, most recognized unsafe water depths but underestimated the danger of moving water. Dynamic LED flood warnings attracted more attention and were judged more effective than static signs.

Matthew Watkins et al, An investigation into driver's perceptions of road flooding and adherence to signage, Transportation Research Part F: Traffic Psychology and Behaviour (2026). DOI: 10.1016/j.trf.2026.103639

original article.

Comment by Dr. Krishna Kumari Challa 15 hours ago

Advertising is coming to AI chatbots—and it could influence the answers you get
Embedding targeted advertising within AI conversations could blur sponsored and organic information, enabling commercial influence over answers and transactions. Personalized, ephemeral chats may amplify misinformation while evading fact-checking and existing regulation. Clear safeguards are needed to prevent sponsors from shaping AI-generated content beyond disclosure labels.

Carlos Diaz Ruiz et al, Advertising in AI Models: How the Zero-Click Internet Threatens Free Markets and Free Speech, Journal of Public Policy & Marketing (2026). DOI: 10.1177/07439156261436399

original article.

Comment by Dr. Krishna Kumari Challa 15 hours ago

Climate change made deadly Nepal glacier and rock collapse more likely, according to analysis
Human-caused warming likely increased instability of the Nepal Himalayan slope by accelerating glacier thinning, retreat, permafrost thaw, and higher freezing elevations. The Aug. 26 collapse, which killed over 1,300 people, may also have been influenced by earthquake-related rock weakening. Rapid failures can exceed warning-system capacity.

This disaster was not an extreme weather event, but the fingerprints of climate change are still clear to see in long-term changes, say the experts.

Climate scientists say that across the Himalayas rising temperatures are causing glaciers to retreat and thawing permanently frozen ground that helps bind fractured mountain rock together. That means climate change can alter not only weather hazards such as heat and heavy rain, but the stability of the mountains themselves—threatening communities concentrated in narrow river valleys below.
The report by the World Weather Attribution
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Comment by Dr. Krishna Kumari Challa 15 hours ago

Earth's atmosphere is getting less dusty: That could be adding to global warming

Atmospheric desert dust has long swirled around the globe, but a new study presents the strongest evidence yet that global dust is mysteriously decreasing. Because atmospheric dust has a slight overall cooling effect on the climate, the researchers say its decrease may have contributed modestly to recent climate warming.

Atmospheric dust declined about 10% from 2003–2023, reversing much of the 20th-century increase. Because dust exerts a small net cooling effect, its reduction likely contributed modestly to recent warming. Causes remain unclear; dust changes also affect nutrient deposition, air quality, and snow and ice reflectivity.
The study, which combined satellite observations, ground-based measurements and atmospheric models, found that the amount of dust in Earth's atmosphere decreased by about 10% from 2003 to 2023.

Most atmospheric dust originates in the Northern Hemisphere, with major desert regions such as the Sahara in North Africa and the deserts of Asia, including the Gobi, contributing much of the global dust burden.

The causes of the recent decline, however, remain unclear, according to the study, published in Science Advances.

Ashok Kumar Gupta et al, A global decline in atmospheric dust during the 21st century, Science Advances (2026). DOI: 10.1126/sciadv.aef5691

Comment by Dr. Krishna Kumari Challa yesterday

'Momnesia' is real—scientists find a biological explanation for temporary forgetfulness during pregnancy

Many women say the same thing during pregnancy: They walk into a room and forget why, misplace their keys or struggle to follow a conversation. This phenomenon, often called "pregnancy brain" or "momnesia," has long lacked a clear biological explanation.
Now, a new study by researchers at Baylor College of Medicine and collaborating institutions, published in Science Bulletin, identifies a specific brain circuit in an animal model that becomes disrupted under the sustained high estrogen levels present during pregnancy. The findings offer the first biological explanation of how exposure to high levels of circulating estrogen can temporarily impair memory.
The new findings suggest a possible explanation—it may not simply be a matter of "more estrogen is better" or "worse," but rather where in the brain estrogen acts and at what levels.

"Low-level, cyclical estrogen exposure appears to support cognitive function, which is part of why hormone therapy can help postmenopausal women.
But sustained, high-level estrogen exposure seems to engage a different pathway altogether, one centered in the hypothalamus rather than the hippocampus itself. That distinction may help reconcile a lot of conflicting data in the field.
Sustained high estrogen impaired task-specific memory in mice by reducing estrogen receptor-α signaling in lateral hypothalamic GABAergic neurons, increasing activity in a hypothalamus–hippocampus circuit. Silencing this pathway prevented impairment. In pregnant women, late-pregnancy memory deficits correlated with estrogen levels and appeared temporary.
To determine whether these findings translate to humans, the researchers assessed memory performance in women across different stages of pregnancy. They found task-specific memory impairments that emerged during late pregnancy and correlated with circulating estrogen levels, even after accounting for other factors that might influence cognition. These human data support the idea that the hormone-driven circuit identified in mice may underlie the memory changes many pregnant women experience.
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Momnesia is real, it has a defined biological basis and is temporary. The memory changes observed in both mice and women were temporary and task-specific, not a sign of broader cognitive decline.

Xin Li et al, High-level estrogen impairs memory via estrogen receptor signaling in a hypothalamic–hippocampal neural circuit, Science Bulletin (2026). DOI: 10.1016/j.scib.2026.08.057

Comment by Dr. Krishna Kumari Challa yesterday

To work around these impediments, the team engineered a nonpathogenic E. coli bacterium to carry a phage that only infects Salmonella. This ensures that when the phage is produced, it can specifically target the pathogen.

Usually, this type of Salmonella phage remains dormant in the Salmonella bacterial genome, but researchers of this study made several genetic modifications so that it is carried by E. coli, and, once it is released into the gut, it automatically kills Salmonella in a process called lysis. This process rapidly increases the number of phages to fight the bacteria. The researchers coined this new type of phage-bacterial combination a "lytic phage-producing lysogen," or "lyto-lysogen."
Salmonella can typically detect phage DNA produced by non-Salmonella bacteria and prevent it from replicating. But in this case, the researchers were able to disguise the phage.
They were able to trick the Salmonella bacteria into thinking the phage from E. coli was 'not foreign' by adding a Salmonella gene into the E. coli genome.
A phage that comes from their E. coli can infect Salmonella, can propagate easily in Salmonella, lyse it, and then all the phages that are produced from Salmonella can just keep replicating."

This rapid reproduction eventually leads to the eradication of the infection from the gut.
What happens is that this good bacterium, the E. coli, produces all this antipathogen phage, and there is now a protective lining so that when Salmonella comes in, just after passing through the stomach and at its weakest point, it meets this high, killer density of phages.
The researchers say they targeted Salmonella due to its high global disease burden, as it can kill the elderly, children and those with HIV; it has a high prevalence of antibiotic resistance; and it has been upgraded to a high-priority pathogen.

Nature Microbiology (2026). DOI: 10.1038/s41564-026-02484-3

Part 2

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Comment by Dr. Krishna Kumari Challa yesterday

First-of-its-kind preventive phage therapy provides promising results against Salmonella
The mammalian gut microbiome teems with a delicate balance of bacteria and the viruses that keep them in check, called bacteriophages, or phages. Each bacterial species usually has its own set of phage partners.
When bad bacteria enter this ecosystem, there are typically no phages present, allowing them to cause mayhem. By the time the host is sick, it is too late for phages; they'll simply reach a balance with the bad bacteria.

But what if the phages in the gut could prepare for the orally ingested pathogen and strike it down as it enters the gut, negating the need for a battle?
Researchers recently demonstrated that this prophylactic approach, using an engineered, nonpathogenic E. coli bacterium, successfully protected mice from an oral Salmonella infection.

Engineered nonpathogenic E. coli produced a modified Salmonella-specific lytic phage in the gut, creating high local phage densities before pathogen exposure. Prophylactic administration protected mice from oral Salmonella infection by enabling phage amplification and bacterial lysis.

Bacteriophages, or phages, are viruses of bacteria and do not infect humans or animals. Phage therapy, the use of phages to treat bacterial infections, is particularly hard to make successful for treating intestinal pathogens.

It's challenging, especially in the gut, because phages and bacteria tend to coexist for long periods of time.

This coexistence makes establishing the high phage-to-bacteria ratio needed to treat intestinal infections hard to achieve.

That's extremely challenging to achieve in your gut.
And then once you have a bacterial infection in your gut, a lot of times it's just not even accessible to phages. It's already hidden away in the mucosa or cells of your body; it's not just free-flowing to where the phages would be able to access the bacteria.
Part 1

Comment by Dr. Krishna Kumari Challa yesterday

Stable frontal signals, flexible hippocampal ones: How the brain preserves context as goals change

While humans are completing a task, they can temporarily store information in their minds while also manipulating and adapting it based on changing circumstances. To support this capability, known as working memory, the brain needs to hold onto important context about a task, updating it when rules, goals or circumstances change.
Researchers recently carried out a study aimed at better understanding how neurons preserve context over time as the goals of an ongoing task change. Their findings, published in Nature Human Behaviour, suggest that the brain can represent the same information through different patterns of neuronal activity that vary in stability and flexibility.
Researchers were inspired by the remarkable ability of an individual to relentlessly pursue a goal over long periods of time, while still remaining flexible and encoding information about a changing environment. No other animal can encounter an arbitrary set of rules or behavioural constraints, immediately internalize them, and adhere to them without continuous reminders or a massive amount of conditioning or reinforcement. So the researchers wanted to study how different structures in the brain perform computations in support of these uniquely human behaviours.
This study offers valuable new insights into how the human brain represents context as people complete tasks. Specifically, it suggests that neurons in the medial frontal cortex can maintain a stable pattern of activity to represent a rule for several minutes, even when reminders of this rule are no longer present.

This mechanism could explain how we are able to continually remember what behaviour to engage in long after the associated instructions or cues for that behaviour are gone.
They also demonstrated that the hippocampus forms a uniquely flexible rule representation whose format changes over time depending on what kind of behaviour the person needs to exhibit. These findings are notable because they draw attention to the utility of rule representations that are stable across time and across incoming stimuli, which is thought to enable the human ability to rapidly generalize behaviour to new contexts.

Hristos S. Courellis et al, Neural dynamics underlying minute-timescale persistent behaviour in the human brain, Nature Human Behaviour (2026). DOI: 10.1038/s41562-026-02537-x.

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