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Comment by Dr. Krishna Kumari Challa 14 hours ago

Microplastics pose human health risk in more ways than one

Microplastics in aquatic environments are colonized by pathogenic and antimicrobial-resistant bacteria, with polystyrene and nurdles posing higher risks due to their capacity to adsorb antibiotics and promote biofilm formation. Over 100 unique antimicrobial resistance gene (ARG) sequences were identified on microplastics, exceeding those on natural or inert substrates. These findings highlight microplastics as vectors for the spread of pathogens and ARGs, raising concerns for environmental and human health.

Emily M. Stevenson et al, Sewers to Seas: exploring pathogens and antimicrobial resistance on microplastics from hospital wastewater to marine environments, Environment International (2025). DOI: 10.1016/j.envint.2025.109944

Comment by Dr. Krishna Kumari Challa 14 hours ago

When the system evolved under this new combined motion, the changes were immediate and dramatic. The researchers measured the LGI violation and found it had smashed the TTB limit, confirming a new level of quantum weirdness.

Beyond this extreme behavior, they discovered that the strength of the LGI violation increased consistently with how much they mixed the two motions.

"This enhanced nonmacrorealism, as quantified by the violation of LGI beyond the TTB, increases with increasing superposition between the unitaries," the researchers noted in their paper.

What's more, the superposed motion protects against the environmental noises that usually disrupt fragile quantum states. Our superposed unitaries provide robustness against such environmental noise by remarkably increasing the time to which LGI violation persists."

This environmental noise, or decoherence, is one of the biggest obstacles in building quantum computers. By overcoming it, this research could help form a blueprint for more stable quantum computers and technologies.

Arijit Chatterjee et al, Extreme Violations of Leggett-Garg Inequalities for a System Evolving under Superposition of Unitaries, Physical Review Letters (2025). DOI: 10.1103/vydp-9qqq. On arXiv: DOI: 10.48550/arxiv.2411.02301

Part 2

Comment by Dr. Krishna Kumari Challa 14 hours ago

Quantum world is even stranger than previously thought, new research confirms

The quantum world is famously weird—a single particle can be in two places at once, its properties are undefined until they are measured, and the very act of measuring a quantum system changes everything. But according to new research published in Physical Review Letters, the quantum world is even stranger than previously thought. 

What happens at the quantum level is in stark contrast to the classical world (what we see every day), where objects have definite properties whether or not we look at them, and observing them doesn't change their nature. To see whether any system is behaving classically, scientists use a mathematical test called the Leggett-Garg inequality (LGI). Classical systems always obey the LGI limit while quantum systems violate it, proving they are non-classical. 

But even in quantum systems, this violation has a limit called the temporal Tsirelson's bound (TTB). In this research, scientists wanted to see if they could break the TTB limit and find even more extreme forms of quantum weirdness. 

They  theorized that a new kind of quantum motion, in which a particle follows two distinct sets of movement instructions simultaneously, could be powerful enough to break the TTB limit. They called this superposition of unitaries.

The team tested their idea in an NMR (nuclear magnetic resonance) machine, which let them control a qubit (the basic building block of quantum information). In this experiment, the qubit was a carbon nucleus within a molecule. The researchers designed a precise quantum circuit using a helper particle (an ancillary qubit) to make the qubit follow two sets of instructions at the same time. Specifically, they combined two different kinds of magnetic rotation on the qubit. 

Part 1

Comment by Dr. Krishna Kumari Challa 14 hours ago

Scientists think they have 'detected' dark matter

In the early 1930s, Swiss astronomer Fritz Zwicky observed galaxies in space moving faster than their mass should allow, prompting him to infer the presence of some invisible scaffolding—dark matter—holding the galaxies together. Nearly 100 years later, NASA's Fermi Gamma-ray Space Telescope may have provided direct evidence of dark matter, allowing the invisible matter to be "seen" for the very first time.

Dark matter has remained largely a mystery since it was proposed so many years ago. Up to this point, scientists have only been able to indirectly observe dark matter through its effects on observable matter, such as its ability to generate enough gravitational force to hold galaxies together.

The reason dark matter can't be observed directly is that the particles that make up dark matter don't interact with electromagnetic force—meaning dark matter doesn't absorb, reflect or emit light.

Theories abound, but many researchers hypothesize that dark matter is made up of something called weakly interacting massive particles, or WIMPs, which are heavier than protons but interact very little with other matter. Despite this lack of interaction, when two WIMPs collide, it is predicted that the two particles will annihilate one another and release other particles, including gamma ray photons.

Researchers have targeted regions where dark matter is concentrated, such as the center of the Milky Way, through astronomical observations for years in search of these specific gamma rays.

Using the latest data from the Fermi Gamma-ray Space Telescope, astronomers think they finally detected the specific gamma rays predicted by the annihilation of theoretical dark matter particles. 

They  detected gamma rays with a photon energy of 20 gigaelectronvolts (or 20 billion electronvolts, an extremely large amount of energy) extending in a halolike structure toward the center of the Milky Way galaxy. The gamma-ray emission component closely matches the shape expected from the dark matter halo.

The observed energy spectrum, or range of gamma-ray emission intensities, matches the emission predicted from the annihilation of hypothetical WIMPs, with a mass approximately 500 times that of a proton. The frequency of WIMP annihilation estimated from the measured gamma-ray intensity also falls within the range of theoretical predictions. 

Importantly, these gamma-ray measurements are not easily explained by other, more common astronomical phenomena or gamma-ray emissions. Therefore, researchers consider these data a strong indication of gamma-ray emission from dark matter, which has been sought for many years. 

The  results, though, must be verified through independent analysis by other researchers. Even with this confirmation, scientists will want additional proof that the halolike radiation is indeed the result of dark matter annihilation rather than originating from some other astronomical phenomena.

Additional proof of WIMP collisions in other locations that harbor a high concentration of dark matter would bolster these initial results. Detecting the same energy gamma-ray emissions from dwarf galaxies within the Milky Way halo, for example, would support this analysis. 

So more work is needed to confirm its presence.

Tomonori Totani, 20 GeV halo-like excess of the Galactic diffuse emission and implications for dark matter annihilation, Journal of Cosmology and Astroparticle Physics (2025). On arXiv : DOI: 10.48550/arxiv.2507.07209

Comment by Dr. Krishna Kumari Challa 14 hours ago

How cancer cells tolerate missing chromosomes

Cancer cells with missing chromosomes maintain protein balance not by reducing protein degradation, but by selectively increasing synthesis of proteins encoded by the lost chromosome. In contrast, cells with extra chromosomes increase degradation of excess proteins. This adaptive mechanism enables cancer cells to tolerate chromosomal imbalances characteristic of aneuploidy.

Yi Di et al, Divergent proteome tolerance against gain and loss of chromosome arms, Molecular Cell (2025). DOI: 10.1016/j.molcel.2025.10.023

Comment by Dr. Krishna Kumari Challa 14 hours ago

The measurements reveal that not all immune cells are created equal—with memory T cells living for 1–2 years in most tissues, while those in the spleen can persist for 3–10 years. Tissue-resident memory T cells (TRM cells) were also found to keep their special protective features throughout life, unlike circulating memory T cells in the blood, which show signs of aging and reduced function.

This shows that while circulating memory T cells develop aging markers, TRM cells are shielded from immunosenescence, a process where immune cells become less effective with age. Lastly, both types of memory T cells undergo changes in their DNA (epigenetic changes) as we age, but TRM cells show more gene regulation, helping them adapt and maintain their protective roles.

The discovery that TRM cells remain stable and avoid aging-related decline could help scientists develop better vaccines and treatments for infections, especially in older adults. It also opens new doors to understanding how our immune system adapts to aging, and how we might boost its resilience. 

Nora Lam et al, Asynchronous aging and turnover of human circulating and tissue-resident memory T cells across sites, Immunity (2025). DOI: 10.1016/j.immuni.2025.07.001

Part 2

Comment by Dr. Krishna Kumari Challa 14 hours ago

Not all immune cells are created equal: Memory T cells in tissues outlast those in blood

Memory T cells are a special type of white blood cell that "remember" past infections and vaccines, helping our bodies to quickly respond if we encounter the same germs again. These cells are found throughout the body: some circulate in the blood, while others settle down as "residents" in tissues like the lungs, intestines and lymphoid organs (such as the spleen and lymph nodes). 

Scientists have long known that memory T cells are crucial for lifelong immunity, but previous studies focused mostly on T cells in the blood. To fill the research gap, scientists  conducted a study to shed light on how long these cells live and persist in different parts of the body, and how aging affects their ability to protect us. Their research is published in Immunity.

The big questions the research team sought to answer were: Do these cells last for years, or are they constantly replaced? Do they lose their protective abilities as we get older? And does where they live in the body make a difference?

To tackle these questions, the team analyzed blood and tissue samples from 138 organ donors, ranging in age from 2 to 93 years. Using the isotope measurement capabilities at LLNL's Center for Accelerator Mass Spectrometry (CAMS), Buchholz was able to analyze the samples by employing a cutting-edge technique called "retrospective radiocarbon birth dating," which measures tiny amounts of a carbon isotope (carbon-14) in the DNA of cells.

Accelerator mass spectrometry works by accelerating ions to extraordinarily high kinetic energies, allowing researchers to count individual carbon-14 atoms in a sample. This level of precision is crucial for accurately estimating the age of cells, since the amount of carbon-14 in the atmosphere has changed over the past several decades due to nuclear testing and other factors. By comparing the carbon-14 content in T cell DNA to historical atmospheric levels, the researchers could determine how long these immune cells had been alive in different tissues.

Part 1

Comment by Dr. Krishna Kumari Challa 14 hours ago

Epigenetic changes regulate gene expression, but what regulates epigenetics?

Cellular instructions are written in a four-letter language—A, T, C, and G—which string together to form long strands of DNA. These long, unruly stretches of DNA are then spooled around proteins called histones and packaged into chromatin—condensing and organizing the strands for easy storage and access. The epigenome is a layer of tags and modifications made on top of all that. These changes determine which genes are and aren't expressed without altering the base code itself, allowing for flexibility in cellular identity and behavior.

One prominent epigenetic tag is DNA methylation, in which a methyl group is tacked onto specific "C" letters within the DNA code. These DNA methylation tags signal for the underlying DNA to be turned "off"—a process called "silencing." This process is important not only for regulating gene expression, but also for silencing the expression of special genetic elements, called transposons. If expressed, transposons can move within the genome, resulting in genome instability and reduced organismal fitness.

Understanding how, when, and why specific DNA methylation patterns are generated in each cell type is crucial for explaining biological development and treating diseases that involve epigenetic dysfunction.

All the cells in an organism have the exact same genetic sequence. What differs across cell types is their epigenetics—meticulously placed chemical tags that influence which genes are expressed in each cell. Mistakes or failures in epigenetic regulation can lead to severe developmental defects in plants and animals alike. This creates a puzzling question: If epigenetic changes regulate our genetics, what is regulating them? 

Scientists  have now used plant cells to discover that a type of epigenetic tag, called DNA methylation, can be regulated by genetic mechanisms. This new mode of plant DNA methylation targeting uses specific DNA sequences to tell the methylation machinery where to dock. Prior to this study, scientists had understood only how DNA methylation was regulated by other epigenetic features, so the discovery that genetic features can also guide DNA methylation patterns is a major paradigm shift.

These findings could inform future epigenetic engineering strategies aimed at generating methylation patterns predicted to repair or enhance cell function, with many potential applications in medicine and agriculture. 

Guanghui Xu et al, Transcription factors instruct DNA methylation patterns in plant reproductive tissues, Nature Cell Biology (2025). DOI: 10.1038/s41556-025-01808-5

Comment by Dr. Krishna Kumari Challa 14 hours ago

Neanderthal women and children were the victims of selective cannibalism at Goyet, study reveals

The study of an assemblage of Neanderthal human bones discovered in the Troisième caverne of Goyet (Belgium) has brought to light selective cannibalistic behavior primarily targeting female adults and children between 41,000 and 45,000 years ago. 

The biological profile of the victims, identified for the first time, reveals that they were part of a group originating from outside of the local community, and they were probably brought to the site where to be consumed for food rather than in a ritual context, as suggested by the presence of traces similar to those found on animal bones hunted, butchered and consumed by occupants of the Goyet site.

The research, which has just been published in Scientific Reports, was conducted by an international team of researchers.

Situating these analyses in the context of the late Middle Paleolithic—marked in Northern Europe by great cultural diversity within Neanderthal groups and the emerging presence of Homo sapiens in nearby areas—such cannibalism directed at specific outsiders could reflect the existence of territorial tensions between groups that preceded the disappearance of Neanderthals in the region.

These conclusions are based on ten years of research involving a reassessment of the Goyet collection through DNA analysis, radiocarbon dating, and isotopic measurements to determine the geographic origin of individuals, in addition to virtual reconstitutions enabling morphological analysis of sometimes very fragmentary human bones.

Quentin Cosnefroy et al, Highly selective cannibalism in the Late Pleistocene of Northern Europe reveals Neandertals were targeted prey, Scientific Reports (2025). DOI: 10.1038/s41598-025-24460-3

Comment by Dr. Krishna Kumari Challa on Tuesday

Research measures how much plastic is lethal for marine life

Marine animals inevitably eat what we put deliberately or unintentionally in the ocean, including pervasive plastics—but how much is too much?

The bar is low, according to a new study out this week: less than three sugar cubes worth could kill birds like Atlantic puffins, for example.

That threshold "is much smaller than scientists expected". 

The paper, published by the Proceedings of the National Academy of Sciences, saw researchers analyze necropsies from more than 10,000 animals in a bid to model how different types of plastic can affect marine life, and at what point the dose turns lethal.

Scientists pulled the necropsy results from dozens of studies and other databases across the globe, using data in which cause of death and plastic consumption information was known. The animals generally were stranded on beaches or otherwise incidentally caught.

Researchers modeled the relationship between plastics ingested and likelihood of death, according to total pieces consumed as well as the volume eaten relative to the size of the animal's digestive tract.

They also examined how different types of plastic affect different types of animals. Seabirds, for instance, were particularly impacted by rubber and hard plastics.

Just six pieces, each smaller than a pea, were 90% likely to cause death in those birds, according to the study.

Sea turtles faced considerable risk from soft plastics like bags.

Those items were also especially deadly for marine mammals, as was fishing gear.

What is worse is half of the individual animals were from species listed as threatened, vulnerable or endangered.

Murphy, Erin L., A quantitative risk assessment framework for mortality due to macroplastic ingestion in seabirds, marine mammals, and sea turtles, Proceedings of the National Academy of Sciences (2025). DOI: 10.1073/pnas.2415492122. doi.org/10.1073/pnas.2415492122

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