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Category: chemistry

Supercomputer simulations reveal rotation drives chemical mixing in red giant stars

Advances in supercomputing have made solving a long‐standing astronomical conundrum possible: How can we explain the changes in the chemical composition at the surface of red giant stars as they evolve?

For decades, researchers have been unsure exactly how the changing chemical composition at the center of a red giant star, caused by nuclear burning, connects to changes in composition at the surface. A stable layer acts as a barrier between the star’s interior and the outer connective envelope, and how elements cross that layer remained a mystery.

In a Nature Astronomy paper, researchers at the University of Victoria’s (UVic) Astronomy Research Center (ARC) and the University of Minnesota solved the problem.

Quantum trembling: Why there are no truly flat molecules

Traditional chemistry textbooks present a tidy picture: Atoms in molecules occupy fixed positions, connected by rigid rods. A molecule such as formic acid (methanoic acid, HCOOH) is imagined as two-dimensional—flat as a sheet of paper. But quantum physics tells a different story. In reality, nature resists rigidity and forces even the simplest structures into the third dimension.

Researchers led by Professor Reinhard Dörner of the Institute for Nuclear Physics at Goethe University have now determined the precise spatial structure of the “flat” formic acid molecule using an X-ray beam from the PETRA III synchrotron radiation source at the DESY accelerator center in Hamburg. They collaborated with colleagues from the universities of Kassel, Marburg and Nevada, the Fritz Haber Institute, and the Max Planck Institute for Nuclear Physics. The study is published in Physical Review Letters.

To accomplish this, they made use of two effects that occur when X-ray radiation strikes a molecule. First, the radiation ejects several electrons from the molecule (photoelectric effect and Auger effect). As a result, the atoms become so highly charged that the molecule bursts apart in an explosion (Coulomb explosion). The scientists succeeded in measuring these processes sequentially, even though they take place within femtoseconds—millionths of a billionth of a second.

Radiation-Induced Optic Neuropathy Following Radiation Therapy for a Recurrent Tuberculum Sellae Meningioma: A Case Report

A new light-based imaging approach has produced an unprecedented chemical map of the Alzheimer’s brain.

Rice University researchers have produced what they describe as the first full, label-free molecular atlas of an Alzheimer’s brain in an animal model. In simple terms, they created a brain-wide “chemical map” that can help scientists study where the disease appears to take hold and how it spreads over time. Alzheimer’s is also a major public health threat, killing more people than breast cancer and prostate cancer combined.

Instead of focusing only on classic pathology markers, the team examined the brain’s underlying chemistry using a light-based imaging approach paired with machine learning. Their study, published in ACS Applied Materials and Interfaces, shows that Alzheimer’s-linked chemical shifts are patchy across the brain rather than uniform. It also suggests those shifts extend beyond amyloid plaques, the best-known feature of the disease.

Chemists synthesize first stable copper metallocene complex, closing a 70-year gap

Almost half a century ago, a remarkable molecule called metallocene took center stage in chemistry, earning Geoffrey Wilkinson and Ernst Otto Fischer the Nobel Prize. These organic compounds, made of a transition metal “sandwiched” between two flat, ring-shaped organic layers, have since become an integral part of new-age polymers, materials, and pharmaceuticals.

In their recent work published in the Journal of the American Chemical Society, a team from University of California brought metallocene back into the limelight with the synthesis of cuprocenes—the first stable version of neutral copper metallocene with the chemical formula Cpttt 2 Cu where Cpttt stands for C5H2tBu3 or bis(tri-tert-butylcyclopentadienyl) ligand. This new complex of copper has blue-green crystals and is stable at room temperature, away from light.

They also produced two new forms of cuprocene: a colorless, negatively charged version via reduction, and a purple, positively charged version via oxidation.

5 Sci-Fi Aliens — And The Likelihood They Could Actually Exist

Special Biology Blog on BigThink on 5 Types of Science Fiction Aliens and the Likelihood that they Actually Exist:

Link through my website Search for Life in the Universe: [ https://www.searchforlifeintheuniverse.com/post/5-sci-fi-ali…ally-exist](https://www.searchforlifeintheuniverse.com/post/5-sci-fi-ali…ally-exist)

While all cellular life on Earth shares the same DNA-based chemistry, planets with different environments could produce alien organisms far more diverse. From insect-like swarms to intelligent machines, many classic sci-fi alien archetypes have at least some grounding in biology, astrobiology, or emerging technology. Ultimately, truly alien life may defy our expectations altogether, and recognizing it could require rethinking not just what aliens look like, but how we define life itself.

Routine vs Selective Calcium Supplementation After Thyroidectomy

Among adults undergoing total thyroidectomy, selective calcium and calcitriol supplementation triggered by low postoperative PTH was not superior to routine supplementation for preventing symptomatic or biochemical hypocalcemia.

Question Is selective calcium and calcitriol (C+C) supplementation, guided by postoperative PTH levels, a better strategy than routine supplementation for preventing symptomatic hypocalcemia after total thyroidectomy?

Findings In this randomized clinical trial of 258 patients, the incidence of symptomatic hypocalcemia in the selective C+C supplementation group (7.8%) compared with the routine C+C supplementation group (11.1%) was not signicantly different.

Meaning Selective C+C supplementation based on postoperative PTH levels is not superior to routine supplementation; both are viable options that can be used according to available resources and clinical context.

Particles don’t always go with the flow (and why that matters)

It is commonly assumed that tiny particles just go with the flow as they make their way through soil, biological tissue, and other complex materials. But a team of Yale researchers led by Professor Amir Pahlavan shows that even gentle chemical gradients, such as a small change in salt concentration, can dramatically reshape how particles move through porous materials. Their results are published in Science Advances.

How small particles known as colloids, like fine clays, microbes, or engineered particles, move through porous materials such as soil, filters, and biological tissue can have significant and wide-ranging effects on everything from environmental cleanups to agriculture.

It’s long been known that chemical gradients—that is, gradual changes in the concentration of salt or other chemicals—can drive colloids to migrate directionally, a phenomenon known as diffusiophoresis. But it was often assumed that this effect would matter only when there was little or no flow, because phoretic speeds are typically orders of magnitude smaller than average flow speeds in porous media. Experiments set up in Pahlavan’s lab demonstrated a very different outcome.

Cheaper green hydrogen? New catalyst design cuts energy losses in AEM electrolyzers

Producing clean hydrogen from water is often compared to storing renewable energy in chemical form, but improving the efficiency of that process remains a scientific challenge. Researchers at Tohoku University have now developed a catalyst design that helps hydrogen form more smoothly under alkaline conditions, a key step toward practical green hydrogen production.

The work is published in the journal ACS Catalysis.

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