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Category: chemistry – Page 4

Atoms tell different stories when light hits a molecule in trillionths of a second

Researchers have captured how a molecule redistributes energy after absorbing light, differentiating the roles of individual atoms in the process. They used X-ray flashes from the European XFEL to show that different atoms in the same molecule can reveal different aspects of the process. The study provides evidence that excitation by light can enhance an atom’s sensitivity to the motion of nearby atoms. The new method for following ultrafast chemical reactions at the atomic scale, in real time, can help researchers understand photostability in DNA, energy flow in light-harvesting materials and other fundamental processes driven by light.

The team investigated 3-fluoropyridine, a small ring-shaped molecule. When the molecule absorbs light, such as a short pulse from an ultraviolet laser, it is promoted into an electronically excited state and rapidly distorts out of its original planar shape. It then passes through a so-called conical intersection: a short-lived but crucial crossing point where movements of electrons and the atoms’ cores become strongly coupled.

After this point, the molecule returns to the ground state. At that moment, electronic energy is converted into vibrations. The researchers found that this conversion leaves distinct fingerprints at different atomic sites: the fluorine atom acts as a clean marker of vibrational relaxation, while the nitrogen atom, which is more directly involved in the excitation, reflects an intertwined response of electron redistribution and structural motion.

Metals’ atomic arrangement can create ‘corrosion highways’ in nuclear reactors

Nuclear reactors are traditionally powered with dense fuel rods that can produce about 1 gigawatt of carbon-free electricity, enough to power about 100,000,000 lightbulbs. Newer power plant designs using molten salt for cooling instead of the water found in traditional reactors could offer better efficiency and stability, but they face a problem—the extreme chemical environment created by the molten salt can corrode the metal comprising the reactor.

A team led by engineers at Penn State found that adjusting the subtle atomic arrangement of structural metals can significantly affect the rate and extent of this corrosion, even with identical baseline chemical compositions. They did this by creating a series of reactive simulations to isolate and study this corrosion mechanism. Their findings are available online ahead of publication in the August issue of Corrosion Science.

Battery-like device pulls CO₂ from air using electricity and saltwater chemistry

Engineers have developed a new way to pull carbon dioxide directly from the atmosphere using a process similar to charging and discharging a battery—an advance that could help address the planet’s excess CO2 problem.

A new collaborative study between scientists at the University of Illinois Urbana-Champaign and Toyota focuses on direct air capture, a technology designed to reduce new emissions and remove CO2 that has already accumulated in the atmosphere. Instead of using heat to absorb and release CO2, as many carbon capture methods do, the new method uses electricity and water-based chemistry within an electrochemical device.

The results of the study by mechanical engineering and science professor Kyle Smith, Illinois graduate students Paul Rozzi and JeongA Lee, and Chip Roberts and Tim Arthur from the Toyota Research Institute of North America are published in the journal Environmental Science & Technology.

A blood protein can flag dementia risk decades before symptoms appear

Forgetting the name of a loved one may be one of the first signs people notice of dementia, but it’s rarely the first warning sign your brain gives. Changes in the brain that lead to neurodegenerative diseases like Alzheimer’s and dementia start showing up decades before symptoms arrive, and the chemicals at work inside the body can often tip us off to these changes well ahead of time.

A recent study found that a blood protein called GDF15, which is released when cells are under stress, could serve as one of the earliest warning signs of dementia. After tracking more than half a million people for 15–25 years, researchers discovered that those with higher GDF15 levels before age 55 were significantly more likely to develop dementia later in life. Finding that protein in the blood was a much stronger predictor of vascular dementia than Alzheimer’s disease and related dementia.

This opens the possibility that a simple blood test in midlife, one that checks for GDF15, could help doctors flag who is at higher risk of dementia decades down the line. The findings are published in Science Advances.

3D-printed battery electrolyte could let devices store power in almost any shape

Researchers at The University of Texas at El Paso have developed a way to 3D-print an essential battery component in nearly any shape. Their innovation could free engineers from the constraints of standard rechargeable battery sizes and allow energy storage to be built directly into the devices the batteries power.

The work, detailed in a study published in Communications Engineering, centers on gel polymer electrolytes, the material inside a battery that carries the ions (the particles that carry the electrical charge) between the electrodes—the two terminals where chemical reactions occur and electricity enters or leaves the battery.

From liquid limits to printable gel Conventional electrolytes are liquids that must be sealed inside rigid casings, a design that limits battery shapes and raises safety concerns about leaks. The UTEP team instead created a printable gel by combining a light-curable resin with a lithium-based liquid electrolyte, then hardening it layer by layer using a technique called vat photopolymerization.

Rust-to-iron cycle may unlock long-term storage for renewable energy

In the future, iron might be used as a chemical energy storage material, making large quantities of renewable energy available in the long term. Iron powder is combusted in a cyclic process that is carbon neutral and then reconverted to its original state using energy input. Scientists at Karlsruhe Institute of Technology (KIT) were the first to conduct an extensive study to evaluate the potential of this technology for power generation. Their results show that iron, while not superseding hydrogen, may usefully complement it in a climate-neutral energy system. The findings have been published in Chem Circularity.

Be it for wind energy from coastal regions or for solar power from desert areas, iron could serve as a transportable energy carrier in the future to make these renewable energy sources usable worldwide. “This works in a cycle that emits no carbon dioxide or environmentally harmful substances,” said Julia Schuler from KIT’s Institute for Industrial Production (IIP). For power generation, iron powder is combusted, producing iron oxide, i.e. rust. Using hydrogen from renewable sources, it is reduced to iron again in a process that removes the oxygen it contains. The iron powder can then be reused.

“When burned, iron powder behaves very much like coal. We wanted to find out whether it was possible to repurpose existing coal power plants to iron-firing,” said Schuler. She believes that modifications are primarily necessary in the heat generator; other components, such as the steam cycle, turbines, generator and power grid connection, could continue to be used.

This unusual epigenetic modifier promotes certain cancers but suppresses others

The epigenetic modifier MLL4 has an unassuming name—the 4, for instance, indicates it’s just one in a family of such modifiers. But MLL4 is quite special: In a specific type of leukemia, it drives disease progression, while in solid tumors, it acts as a suppressor.

The paradoxical nature of MLL4 made it a compelling enigma for Rockefeller University’s Robert Roeder, a pioneer in the field of genetic transcription. Now his Laboratory of Biochemistry and Molecular Biology at Rockefeller University has used a combination of biochemistry, genetics and structural biology to find surprising new characteristics of MLL4 that expand our understanding of its range of functions, including its relationship to a tumor-suppressing protein. The findings, published in Molecular Cell, could illuminate how the MLL4 complex helps switch genes on—including cancer genes in leukemia.

“This research demonstrates that MLL4 has functions in transcription that were entirely unknown before,” says Roeder. “And because MLL4 is a key regulator of gene activity, it’s important to understand how it works—especially in cancer cells.”

Visible light triggers three-step cascade to make 3D drug-like molecules

A team led by chemist Frank Glorius, a professor at the Institute of Organic Chemistry at the University of Münster, has developed a new light-driven reaction sequence. In this triple catalysis, one reaction step triggers the next like three dominoes in a row, toppling one after the other. The molecular transformations occur sequentially in a single reaction vessel. Such one-pot synthesis is considered an ideal process because it is particularly resource- and energy-efficient.

Harvard scientists turn a silicon chip into a DNA writing machine

Scientists have created a silicon chip that can write dozens of DNA sequences simultaneously using electricity and water-based enzymes, offering a cleaner alternative to conventional DNA manufacturing. The breakthrough could eventually support portable DNA-writing devices and even massive DNA data storage, although new chemistry will be needed to scale the technology further.

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