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Category: chemistry – Page 12

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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A collaborative research team has introduced a nitrogen-centric framework that explains the light-absorbing effects of atmospheric organic aerosols. Published in Science, this study reveals that nitrogen-containing compounds play a dominant role in the absorption of sunlight by atmospheric organic aerosols worldwide. This discovery signifies a major step towards improving climate models and developing more targeted strategies to mitigate the climate impact of airborne particles.

Atmospheric organic aerosols influence climate by absorbing and scattering sunlight, particularly within the near-ultraviolet to visible range. Due to their complex composition and continuous chemical transformation in the atmosphere, accurately assessing their climate effects has remained a challenge.

The study was jointly led by Prof. Fu Tzung-May, Professor of the School of Environmental Science and Engineering at Southern University of Science and Technology (SUSTech) and National Center for Applied Mathematics Shenzhen (NCAMS), and Prof. Yu Jianzhen, Chair Professor of the Department of Chemistry and the Division of Environment and Sustainability at Hong Kong University of Science and Technology (HKUST).

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Scientists at Yokohama National University, in collaboration with RIKEN and other institutions in Japan and Korea, have made an important discovery about how electrons move and behave in molecules. This discovery could potentially lead to advances in electronics, energy transfer, and chemical reactions.

Published in the Science, their study reveals a new way to control the distribution of electrons in molecules using very fast phase-controlled pulses of light in the .

Atoms and molecules contain negatively charged electrons that usually stay in specific energy levels, like layers, around the positively charged nucleus. The way these electrons are arranged in the molecule is key to how the molecule behaves.

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Iron oxide minerals are found in rocks around the globe. Some are magnetic, and some of them rust—especially when exposed to water and oxygen. These characteristics provide clues about the history of these minerals.

Utah State University geoscientists describe a new forensic tool for determining the timing of geochemical oxidation reactions in minerals occurring in the Earth’s crust, which could shed light on how and when large, unexplained gaps in the rock record—known as “unconformities”—developed.

“A challenge for geoscientists is accurately constraining when rocks resided in the near-surface environment,” says Alexis Ault, associate professor in USU’s Department of Geosciences. “It’s tricky to pinpoint the timing of such processes, because the has often been erased.”

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Researchers have developed a reactor that pulls carbon dioxide directly from the air and converts it into sustainable fuel, using sunlight as the power source.

The researchers, from the University of Cambridge, say their solar-powered reactor could be used to make fuel to power cars and planes, or the many chemical and pharmaceutical products we rely on. It could also be used to generate fuel in remote or off-grid locations.

Unlike most carbon capture technologies, the reactor developed by the Cambridge researchers does not require fossil-fuel-based power, or the transport and storage of carbon dioxide, but instead converts atmospheric CO2 into something useful using sunlight. The results are reported in the journal Nature Energy.

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