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Category: chemistry – Page 13

Using the James Webb Space Telescope (JWST), astronomers have observed enigmatic rings in the planetary nebula NGC 1,514, visible in the mid-infrared band. Results of the new observations, published Feb. 28 on the arXiv pre-print server, shed more light on the properties and nature of these rings.

Planetary nebulae (PNe) are expanding shells of gas and dust that have been ejected from a star during the process of its evolution from a into a red giant or white dwarf. They are relatively rare, but are important for astronomers studying the chemical evolution of stars and galaxies.

NGC 1,514 (also known as Crystal Ball Nebula) is a large and complex elliptical planetary at a distance of about 1,500 light years away. It originated from a designated HD 281679. The bright, visible component of the system is a giant star of spectral type A0III, while the nebula-generating companion is now a hot, sub-luminous O-type star.

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Many biologically important molecules change shape when stimulated by UV radiation. Although this property can also be found in some drugs, it is not yet well understood. Using an innovative technique, an international team involving researchers from Goethe University Frankfurt, the European XFEL in Schenefeld and the Deutschen Elektronen-Synchrotron DESY in Hamburg has elucidated this ultra-fast process, and made it visible in slow motion, with the help of X-ray light. The method opens up exciting new ways of analyzing many other molecules.

The study is published in the journal Nature Communications.

“We investigated the molecule 2-thiouracil, which belongs to a group of pharmaceutically active substances based on certain DNA building blocks, the nucleobases,” says the study’s last author Markus Gühr, the head of DESY’s free-electron laser FLASH and Professor of Chemistry at University of Hamburg. 2-thiouracil and its chemically related active substances have a sulfur atom, which gives the molecules its unusual, medically relevant properties.

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Researchers from Japan and Taiwan have made a groundbreaking discovery, demonstrating for the first time that helium—long considered chemically inert—can bond with iron under extreme pressure. Using a laser-heated diamond anvil cell, they observed this unexpected interaction, suggesting that vast amounts of helium may be present in the Earth’s core. This finding challenges long-held theories about the planet’s internal structure and history and could provide new insights into the primordial nebula from which our solar system originated.

Volcanic eruptions primarily release rocks and minerals, but they can also emit traces of a rare gas known as primordial helium. Unlike the more common isotope, helium-4 (⁴He), which consists of two protons and two neutrons and is continuously produced by radioactive decay, primordial helium—helium-3 (³He)—contains only one neutron and is not formed on Earth. Its presence offers valuable clues about the planet’s deep interior and its connection to cosmic origins.

Given the occasionally high 3 He/4He ratios found in volcanic rocks, especially in Hawaii, researchers have long believed there are primordial materials containing 3 He deep within the mantle. However, graduate student Haruki Takezawa and members of Professor Kei Hirose’s group from the University of Tokyo’s Department of Earth and Planetary Science have now challenged this view with a new take on a familiar experiment — crushing things.

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The world’s demand for alternative fuels and sustainable chemical products has prompted many scientists to look in the same direction for answers: converting carbon dioxide (CO2) into carbon monoxide (CO).

But the labs of Yale chemists Nilay Hazari and James Mayer have a different chemical destination in mind. In a new study, Hazari, Mayer, and their collaborators present a new method for transforming CO2 into a chemical compound known as formate — which is used primarily in preservatives and pesticides, and which may be a potential source of more complex materials.

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The discovery of a mini aurora above a light-emitting polymer material reveals an electron-ejection process that might be useful in field-emission displays and material fabrication.

Auroras occur in the night sky when charged solar-wind particles, such as protons and electrons, are deflected by Earth’s magnetic field and interact with molecules in the atmosphere. Researchers have now found an aurora-like emission coming from a light-emitting polymer [1]. The surprising display consisted of flashes of green light above the polymer surface. The researchers explained the emission as the result of electrons being ejected from the polymer and interacting with a vapor of organic molecules. The discovery suggests that these polymers might be useful as electron emitters for applications such as spectroscopy, medical technology, and lithography.

Jun Gao from Queen’s University in Canada is amazed by auroras, and he’s even gone out on cold nights to look for them. But he was not prepared for the aurora that showed up in his lab two years ago. He and his student at the time, Dongze Wang, were testing failure modes for polymer light-emitting electrochemical cells, or PLECs, used in light sources and display devices. These cells are organic semiconductors that are electrochemically doped on one side to have excess electrons (making an n-type semiconductor) and on the other side to have electron deficiencies, or holes (making a p-type semiconductor). Electrons crossing the p – n boundary can fill holes and produce red light.

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Eye injuries that damage the cornea are usually irreversible and cause blindness. But a new clinical trial has repaired this damage in patients thanks to a transplant of stem cells from their healthy eyes.

The cornea is the outer layer of the eye, which focuses light towards the retina. Since it’s on the frontline of potential hazards from the outside world, the cornea features a population of limbal epithelial stem cells, which repair minor damage to keep the surface smooth and functional.

Unfortunately, injuries like thermal or chemical burns can damage the cornea beyond the capability of these resident stem cells. There’s not much else that can be done – even a cornea transplant won’t take hold if the damage is too severe.

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A team of researchers has developed the first chip-scale titanium-doped sapphire laser—a breakthrough with applications ranging from atomic clocks to quantum computing and spectroscopic sensors.

The work was led by Hong Tang, the Llewellyn West Jones, Jr. Professor of Electrical Engineering, Applied Physics & Physics. The results are published in Nature Photonics.

When the titanium-doped laser was introduced in the 1980s, it was a major advance in the field of lasers. Critical to its success was the material used as its gain medium—that is, the material that amplifies the laser’s energy. Sapphire doped with titanium ions proved to be particularly powerful, providing a much wider laser emission bandwidth than conventional semiconductor lasers. The innovation led to fundamental discoveries and countless applications in physics, biology, and chemistry.

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Composite adhesives like epoxy resins are excellent tools for joining and filling materials including wood, metal, and concrete. But there’s one problem: once a composite sets, it’s there forever. Now there’s a better way. Researchers have developed a simple polymer that serves as a strong and stable filler that can later be dissolved. It works like a tangled ball of yarn that, when pulled, unravels into separate fibers.

A new study led by researchers at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) outlines a way to engineer pseudo-bonds in materials. Instead of forming chemical bonds, which is what makes epoxies and other composites so tough, the chains of molecules entangle in a way that is fully reversible. The research is published in the journal Advanced Materials.

“This is a brand new way of solidifying materials. We opened a new path to composites that doesn’t go with the traditional ways,” said Ting Xu, a faculty senior scientist at Berkeley Lab and one of the lead authors for the study.

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