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Category: chemistry – Page 7

How the fight-or-flight response resets on a molecular level

Being cut off in traffic, giving a presentation or missing a meal can all trigger a suite of physiological changes that allow the body to react swiftly to stress or starvation. Critical to this “fight-or-flight” or stress response is a molecular cycle that results in the activation of protein kinase A (PKA), a protein involved in everything from metabolism to memory formation. Now, a study by researchers at Penn State has revealed how this cycle resets between stressful events, so the body is prepared to take on new challenges.

The details of this reset mechanism, uncovered through a combination of imaging, structural and biochemical techniques, are published in the Journal of the American Chemical Society.

“Some of the early changes in the fight-or-flight response include the release of hormones, like adrenaline from stress or glucagon from starvation,” said Ganesh Anand, associate professor of chemistry and of biochemistry and in the Penn State Eberly College of Science and lead author of the paper.

Artificial cell-like structures mimic self-reproduction and release polymeric spores

Life on Earth possesses an exceptional ability to self-reproduce, which, even on a simple cellular level, is driven by complex biochemistry. But can self-reproduction exist in a biochemistry-free environment?

A study by researchers from Harvard University demonstrated that the answer is yes.

The researchers designed a non-biochemical system in which synthetic cell-like structures form and self-reproduce by ejecting polymeric spores.

Oxygenation in the ocean may have occurred earlier than previously thought, offering new insights into Earth’s evolution

Several key moments in Earth’s history help us humans answer the question “How did we get here?” These moments also shed light on the question “Where are we going?” and offer scientists deeper insight into how organisms adapt to physical and chemical changes in their environment.

Among them is an extended evolutionary occurrence over 2 billion years ago, known as the Great Oxidation Event (GOE). This marked the first time that oxygen produced by photosynthesis—essential for the survival of humans and many other life forms—began to accumulate in significant amounts in the atmosphere.

If you traveled back in time to before the GOE (more than 2.4 billion years ago), you would encounter a largely anoxic (oxygen-free) environment. The organisms that thrived then were anaerobic, meaning they didn’t require oxygen and relied on processes like fermentation to generate energy. Some of these organisms still exist today in extreme environments such as acidic hot springs and hydrothermal vents.

Asymmetry of cross kinetic coefficients in the cell model of a charged membrane

Theoretical study was performed earlier for the cell model of a charged porous membrane based on Onsager’s approach and the result was calculation of all electrokinetic coefficients. Experimental dependences of electroosmotic permeability, conductivity, and diffusion permeability of some perfluorinated membranes on electrolyte concentration were simultaneously and quantitatively described using exact analytical formulae based on the same set of physicochemical and geometrical parameters. It is shown here that for the developed cell model of the ion–exchange membrane, the Onsager principle of reciprocity is violated—the coupled cross kinetic coefficients are not equal.

Scientists Discover Violation of 1931 Thermodynamic Principle

The cell model of ion-exchange membranes reveals violations of the Onsager reciprocity principle, particularly at high electrolyte concentrations, highlighting the importance of accounting for asymmetric transport coefficients. Ion-exchange membranes are widely used in electrochemical and separat

Prototype sodium-air fuel cell could power electric planes and trains

Batteries are nearing their limits in terms of how much power they can store for a given weight. That’s a serious obstacle for energy innovation and the search for new ways to power airplanes, trains, and ships. Now, researchers at MIT and elsewhere have come up with a solution that could help electrify these transportation systems.

Instead of a battery, the new concept is a kind of fuel cell which is similar to a battery but can be quickly refueled rather than recharged. In this case, the fuel is liquid sodium metal, an inexpensive and widely available commodity.

The other side of the cell is just ordinary air, which serves as a source of oxygen atoms. In between, a layer of solid ceramic material serves as the electrolyte, allowing sodium ions to pass freely through, and a porous air-facing electrode helps the sodium to chemically react with oxygen and produce electricity.

Self-stirring nanoreactors enhance reaction efficiency for chemical synthesis

Recent technological advances have opened new possibilities for the efficient and sustainable synthesis of various valuable chemicals. Some of these advances rely on nanotechnologies, systems or techniques designed to design and study materials or devices at the nanometer scale.

Nanoreactors are nanotechnologies designed to host and control within confined spaces. These small structures serve as tiny “reaction vessels” that enable the precise manipulation of the reactants, catalysts and conditions to elicit desired chemical reactions.

Researchers at Inner Mongolia University, Fudan University and Julin University in China recently developed a new paddle-like mesoporous silica nanoreactor that can stir itself when exposed to a rotating magnetic field. This nanoreactor, outlined in a paper published in Nature Nanotechnology, can mix chemicals at a , enhancing the efficiency of reactions and thus potentially enhancing the synthesis of various compounds.

Spectroscopic study inspects blue straggler stars in NGC 3201

Using the Magellan Clay Telescope, astronomers have performed a spectroscopic study of blue straggler stars in the globular cluster NGC 3201. Results of the new study, published May 21 on the arXiv preprint server, could help us better understand the properties and chemical composition of this cluster.

First identified in the 1950s, the blue straggler stars (BSSs) are unique main-sequence (MS) stars that are brighter, bluer, and appear younger than their coeval counterparts, hence more massive than MS stars. They are positioned to the left and above the main-sequence turnoff (MSTO) in the optical color-magnitude diagram (CMD).

One of the places to look for and investigate the BSS population are (GCs)—gravitationally bound groups of stars. Due to their relatively high masses, the blue straggler stars can be used to probe the internal dynamics of GCs.

Cosmic ray research helps unravel lithium-7 origin

The origin of lithium (Li), the third element of the periodic table, has long been shrouded in mystery. This element, commonly found in cosmic rays as two stable isotopes, 6 Li and 7 Li, is crucial to understanding the origins of the universe and the evolution of its chemical elements.

In a recent study, an international team of researchers used the Alpha Magnetic Spectrometer (AMS-02) aboard the International Space Station to measure the cosmic-ray fluxes of 6 Li and 7 Li based on data accumulated from May 2011 to October 2023.

Based on information from over 2 million nuclei amassed across 12 years, the team formulated a hypothesis that strengthens the case for one possible origin of lithium while challenging another previously accepted explanation.

Glaphene: 2D hybrid material integrates graphene and silica glass for next-generation electronics

Some of the most promising materials for future technologies come in layers just one atom thick, such as graphene, a sheet of carbon atoms arranged in a hexagonal lattice, prized for its exceptional strength and conductivity. While hundreds of such materials exist, truly merging them into something new has remained a challenge. Most efforts simply stack these atom-thin sheets like a deck of cards, but the layers typically lack significant interaction between them.

An international team of researchers led by Rice University materials scientists has succeeded in creating a genuine 2D hybrid by chemically integrating two fundamentally different 2D materials—graphene and —into a single, stable compound called glaphene, according to a study published in Advanced Materials.

“The layers do not just rest on each other; electrons move and form new interactions and vibration states, giving rise to properties neither material has on its own,” said Sathvik Iyengar, a doctoral student at Rice and a first author on the study.