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Comment by Dr. Krishna Kumari Challa 3 hours ago

Solar Analemma

Why the Sun Makes a Figure Eight in the Sky

The figure-8 pattern is due to a combination of the tilt of Earth's axis and the ellipticity of Earth's orbit which cause the Sun's position to change over the course of a year.

Comment by Dr. Krishna Kumari Challa 5 hours ago

Aged dust particles act as 'chemical reactors in sky' to drive air pollution, study finds

Dust particles thrown up from deserts such as the Sahara and Gobi are playing a previously unknown role in air pollution, a new study has found.

The international study published in National Science Review has revealed that, contrary to long-held scientific assumptions, aged desert dust particles, which were once considered too big and dry to host significant chemical reactions, actually act as "chemical reactors in the sky"—facilitating the formation of secondary organic aerosols (SOA), a major component of airborne particles.

Published in a collaborative effort led by scientists from China, Japan, the UK, and other nations, the study shows that during dust events such as those stemming from the Sahara and Gobi deserts, around 50% of water-soluble secondary organic aerosols, primarily considered as SOA, are found in coarse (supermicron) dust particles.

This finding challenges the conventional wisdom on its head as, until now, scientists thought that such SOA is primarily formed in fine (submicron) particles or cloud droplets.

This discovery marks a major advance in understanding the chemistry of secondary organic aerosols.

The team found that the formation of secondary organic aerosols (SOA) occurs in water-containing coatings of aged dust, specifically those that have reacted with atmospheric nitric acid to form calcium nitrate. This compound absorbs water even in dry conditions (relative humidity as low as 8%), creating a micro-environment where gas-phase pollutants like glyoxal can dissolve, react, and form aqueous-phase secondary organic aerosol (aqSOA).

To validate their findings, the team combined cutting-edge microscopic analysis with global-scale computer modeling. They showed that these dust-driven reactions could account for up to two thirds of total secondary organic aerosol in some of the world's dustiest regions, from North Africa to East Asia—orders of magnitude more than previous estimates.

Air pollution from fine particles is linked to millions of premature deaths annually and contributes to climate change. Understanding how and where these particles form helps improve forecasts, guide pollution controls, and ultimately protect human health.

Weijun Li et al, Aqueous-phase secondary organic aerosol formation on mineral dust, National Science Review (2025). DOI: 10.1093/nsr/nwaf221

Comment by Dr. Krishna Kumari Challa 5 hours ago

Airborne toxin detected in Western Hemisphere for the first time

Once in a while, scientific research resembles detective work. Researchers head into the field with a hypothesis and high hopes of finding specific results, but sometimes, there's a twist in the story that requires a deeper dive into the data.

That was the case for some researchers who led a field campaign in an agricultural region of Oklahoma. Using a high-tech instrument to measure how aerosol particles form and grow in the atmosphere, they stumbled upon something unexpected: the first-ever airborne measurements of medium chain chlorinated paraffins (MCCPs), a kind of toxic organic pollutant, in the Western Hemisphere. Their results published today in ACS Environmental Au.

MCCPs are currently under consideration for regulation by the Stockholm Convention, a global treaty to protect human health from long-standing and widespread chemicals. While the toxic pollutants have been measured in Antarctica and Asia, researchers haven't been sure how to document them in the Western Hemisphere's atmosphere until now.

MCCPs are used in fluids for metalworking and in the construction of PVC and textiles. They are often found in wastewater and as a result, can end up in biosolid fertilizer, also called sewage sludge, which is created when liquid is removed from wastewater in a treatment plant. Researchers suspect the MCCPs they identified came from biosolid fertilizer in the fields near where they set up their instrument. When sewage sludges are spread across the fields, those toxic compounds could be released into the air, the researchers said. They can't show directly that that's happening, but they think it's a reasonable way that they could be winding up in the air. Sewage sludge fertilizers have been shown to release similar compounds.

Daniel John Katz et al, Real-Time Measurements of Gas-Phase Medium-Chain Chlorinated Paraffins Reveal Daily Changes in Gas-Particle Partitioning Controlled by Ambient Temperature, ACS Environmental Au (2025). DOI: 10.1021/acsenvironau.5c00038

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Comment by Dr. Krishna Kumari Challa 6 hours ago

Statins may reduce risk of death by 39% for patients with life-threatening sepsis, large study finds

Sepsis is when the immune system overshoots its inflammatory reaction to an infection, so strongly that the vital organs begin to shut down. It is life-threatening.

In about 15% of cases, sepsis worsens into septic shock, characterized by dangerously low blood pressure and reduced blood flow to tissues. The risk of death from septic shock is even higher, between 30% and 40%.

The earlier patients with sepsis are treated, the better their prospects. Typically, they receive antibiotics, intravenous fluids, and vasopressors to raise blood pressure. But now, a large cohort study published in Frontiers in Immunology has shown for the first time that supplementary treatment with statins could boost their chances of survival.

This cohort study found that treatment with statins was associated with a 39% lower death rate for critically ill patients with sepsis, when measured over 28 days after hospital admission.

Statins are best known as a protective treatment against cardiovascular disease, which function by lowering 'bad' LDL cholesterol and triglycerides, and raising 'good' HDL cholesterol. But they have been shown to bring a plethora of further benefits, which explains the burgeoning interest in their use as a supplementary therapy for inflammatory disorders, including sepsis.

Not just lowering cholesterol,  Statins have anti-inflammatory, immunomodulatory, antioxidative, and antithrombotic properties too. They may help mitigate excessive inflammatory response, restore endothelial function, and show potential antimicrobial activities.

The authors sourced their data from the public Medical Information Mart for Intensive Care-IV (MIMIC-IV) database, which holds the anonymized e-health records of 265,000 patients admitted to the emergency department and the intensive care unit of the Beth Israel Deaconess Medical Center of Boston between 2008 and 2019. Only adults with a diagnosis of sepsis hospitalized for longer than 24 hours were included.

The authors compared outcomes between patients who received or didn't receive any statins during their stay besides standard of care, regardless of the type of statin.

The results showed that the 28-day all-cause mortality rate was 14.3% in the statin group and 23.4% in the no statin group, indicating a relative reduction of 39% [9.1 percentage points].

"These results strongly suggest that statins may provide a protective effect and improve clinical outcomes for patients with sepsis," concluded the researchers.

Statin use during Intensive Care Unit Stay Is Associated with Improved Clinical Outcomes in Critically Ill Patients with Sepsis: A Cohort Study, Frontiers in Immunology (2025). DOI: 10.3389/fimmu.2025.1537172

Comment by Dr. Krishna Kumari Challa 7 hours ago

With the world moving towards more sustainable options, researchers have been on the lookout for high-performance, non-toxic adhesives derived from renewable resources.

Several studies have ventured into the extraction of bio-based adhesives from natural sources like soybean protein, starch, chitin, cellulose, and lignin. However, they suffered from limitations such as low bonding strength and lack of reusability.
To synthesize the high-performance bio-based adhesive, the researchers sourced xylan from viscose fiber mills, which were then freeze-dried and oxidized in the sodium periodate (NaIO4) solution. This step selectively oxidized the 2,3-hydroxyl groups of xylan into aldehyde groups while cleaving the carbon bonds (C2–C3) in the anhydroxylose units, resulting in dialdehyde xylan (DAX).

After purification, the DAX powder was treated with a monobasic sodium phosphate solution, followed by sodium borohydride (NaBH4), which reduced the hydroxyl groups and yielded the final product, dialcohol xylan (RDAX).
The researchers used the xylan adhesive to bond together some woodchips and found that it exhibited a lap-shear strength—the ability to maintain adhesion when force is applied parallel to the bonded joint—of up to around 30 MPa, a value that surpasses many commercially available HMAs. High-performance hot-melt adhesive (XA) also works well in extreme cold, too, maintaining strong adhesion even at –25°C.

This enhanced adhesion strength traces back to the formation of a continuous layer that mechanically interlocks with the wood by penetrating its vessel pores. At the molecular level, strong adhesion arises primarily from hydrogen bonding and van der Waals forces between the adhesive and the substrate surface.

A biocompatible and reusable adhesive obtained from a waste byproduct strengthens the shift towards a greener and more circular economy.

Ziwen Lv et al, Bio-based hot-melt adhesive from xylan, Nature Sustainability (2025). DOI: 10.1038/s41893-025-01579-9

Part 2

Comment by Dr. Krishna Kumari Challa 7 hours ago

New bio-based hot glue made from industrial leftovers outperforms commercial adhesives

A new bio-based hot glue derived from a byproduct of the wood pulp industry beats traditional epoxy resins and commercial hot-melt glues in terms of adhesive performance.

Researchers developed a hot-melt adhesive derived from xylan—a complex sugar found in plant cell walls—that can be applied in a molten state and reused over 10 times without any loss of its original strength. 

Adhesives don't just bond materials, they are the backbone of industrial manufacturing in sectors like packaging, construction and electronics. They are often divided into groups—solvent-based adhesives, reactive adhesives, and hot-melt adhesives (HMAs)—based on how they cure (dry or harden).

Unfortunately, most industrial-grade adhesives available on the market are extracted from petroleum-based products, which can have a negative impact on human and environmental health.

Despite being derived from fossil fuels, HMAs have been preferred over other potentially toxic adhesives since their introduction in the 1950s. They are primarily composed of four key ingredients: polymers, which provide strength and control tackiness; resins, which enhance adhesion to various surfaces; waxes, which improve curing speed and heat resistance; and additives, which help boost stability and extend shelf life.

Being solvent-free and solid at room temperature, HMAs must be melted before use. Once applied and cooled, they form strong bonds quickly—delivering excellent mechanical performance without releasing harmful volatile organic compounds (VOCs).

Part 1

Comment by Dr. Krishna Kumari Challa yesterday

Breakthrough cholesterol treatment can cut levels by 69% after one dose

The future of heart attack prevention could be as easy as a single injection

A single shot of a new drug can lower cholesterol levels by up to 69 per cent, according to the initial results of a clinical trial that has not yet been peer reviewed.

The treatment, called VERVE-102, could transform the future of heart attack prevention by dramatically reducing a person's levels of LDL cholesterol – the so-called ‘bad’ cholesterol – with just one injection.

While statins can lower a person’s cholesterol levels by similar levels, these generally need to be taken daily.

Instead of managing cholesterol over time like statins, VERVE-102 aims to provide a one-time fix by ‘switching off’ a specific gene, known as PCSK9, in the liver. This gene plays a key role in regulating how much LDL cholesterol the liver can detect and remove from the bloodstream. 

Essentially, less PCSK9 leads to less LDL in the bloodstream.

Comment by Dr. Krishna Kumari Challa yesterday

Iron-deficient male mice can grow ovaries
Male mouse fetuses can develop female organs in utero if their mother is iron deficient during pregnancy. When pregnant mice were given a molecule that sequesters iron, or their embryos had genetic tweaks that disrupted their iron uptake, a handful of pups with XY chromosomes in their litters grew ovaries. The findings could have implications for medical advice about iron intake during pregnancy. But as most embryos developed typical sexual characteristics, there must be other key factors that influence sex.

https://www.nature.com/articles/s41586-025-09063-2.epdf?sharing_tok...

Comment by Dr. Krishna Kumari Challa yesterday

two particularly important findings:

On a dataset of questions designed to test for social biases in language models, they found cases in which LLMs provide explanations that mask their reliance on social biases. In other words, the LLMs make decisions that are influenced by social identity information, such as race, income, and gender—but then they justify their decisions based on other factors, such as an individual's behavior.
On a dataset of medical questions involving hypothetical patient scenarios, the team's method revealed cases in which LLM explanations omit pieces of evidence that have a large effect on the model's answers regarding patient treatment and care.
The research team says that, by uncovering specific patterns in misleading explanations, their method can enable a targeted response to unfaithful explanations.

Katie Matton et al. Walk the Talk? Measuring the Faithfulness of Large Language Model Explanations. ICLR 2025 Spotlight. openreview.net/forum?id=4ub9gpx9xw

Part 2

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Comment by Dr. Krishna Kumari Challa yesterday

How can we tell if AI is lying? New method tests whether AI explanations are truthful

Given the recent explosion of large language models (LLMs) that can make convincingly human-like statements, it makes sense that there's been a deepened focus on developing the models to be able to explain how they make decisions. But how can we be sure that what they're saying is the truth?

In a new paper, researchers from Microsoft and MIT's Computer Science and Artificial Intelligence Laboratory (CSAIL) propose a novel method for measuring LLM explanations with respect to their "faithfulness"—that is, how accurately an explanation represents the reasoning process behind the model's answer.

If an LLM produces explanations that are plausible but unfaithful, users might develop false confidence in its responses and fail to recognize when recommendations are misaligned with their own values, like avoiding bias in hiring.

In areas like health care or law, unfaithful explanations could have serious consequences: the researchers specifically call out an example in which GPT-3.5 gave higher ratings to female nursing candidates compared to male ones even when genders were swapped, but explained its answers to be affected only by age, skills, and traits.

Prior methods for measuring faithfulness produce quantitative scores that can be difficult for users to interpret—what does it mean for an explanation to be, say, 0.63 faithful? 

To accomplish this, they introduced "causal concept faithfulness," which measures the difference between the set of concepts in the input text that the LLM explanations implies were influential to those that truly had a causal effect on the model's answer. Examining the discrepancy between these two concept sets reveals interpretable patterns of unfaithfulness—for example, that an LLM's explanations don't mention gender when they should.

Part 1

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