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Archive for the ‘chemistry’ category: Page 34

Mar 22, 2024

Heavy Element Quandary in Stars Worsened by New Nuclear Data

Posted by in categories: chemistry, particle physics

Astrophysicists have a cerium problem—models predict that certain stars should contain much less of this heavy element than astrophysical observations find. Recently performed experiments at CERN’s neutron time-of-flight (n_TOF) facility have widened the gap between theory and observations by 20% [1]. The researchers behind the work say that the results highlight the need for high-accuracy measurements of the nuclear properties of atoms, as well as for updated nucleosynthesis models of element formation. “Our experiment made the problem worse,” says Simone Amaducci of the INFN Laboratori Nationali del Sud, Italy. “That was unexpected, but it’s also interesting because it means there is something we don’t understand about how nucleosynthesis happens.”

Most of the Universe’s heavier elements form in stars via one of the so-called neutron-capture processes, in which an atomic nucleus absorbs one or more neutrons. In the slow neutron-capture process, or “s process,” the absorptions are spread out in time. As such, each absorption event results in either a stable nucleus with the same number of protons but one additional neutron or an unstable nucleus, which then radioactively decays to produce the nucleus of the next element in the periodic table—the one with one additional proton.

Using currently available models of the s process, researchers have correctly predicted the abundances of elements as heavy as barium (56 protons), lanthanum (57 protons), praseodymium (59 protons), and neodymium (60 protons) in stars that are known to be enriched via the s process. But the models appear to break down for cerium (58 protons), as the abundance predictions for this element in some low-mass, low-metallicity globular cluster stars have disagreed by up to 30% with observations. “This discrepancy is very strange, as the theory works for the neighboring elements,” says Sergio Cristallo, a team member who works on problems related to neutron capture at the National Institute of Astrophysics in Italy. “There is nothing in the models that should cause such a discrepancy just for one element.”

Mar 22, 2024

Novel Material Increases Perovskite Solar Cell Efficiency by 15.8%

Posted by in categories: chemistry, solar power, sustainability

In an article published in the Journal of Materials Chemistry C, Brazilian researchers describe a strategy to enhance the efficiency and stability of solar cells made of perovskite, a semiconductor material produced in the laboratory. The results of the project could be highly positive for the future of the solar power sector.

Developed by researchers at São Paulo State University (UNESP) in Bauru, Brazil, the method involves the use of a class of materials known as MXenes, a family of two-dimensional materials with a graphene-like structure combining transition metals, carbon and/or nitrogen, and surface functional groups such as fluoride, oxygen or hydroxyl. Their properties include high electrical conductivity, good thermal stability, and high transmittance (relating to the amount of light that passes through a substance without being reflected or absorbed).

Mar 21, 2024

Pushing the limit of the periodic table with superheavy elements

Posted by in categories: chemistry, particle physics

Scientists from Massey University in New Zealand, the University of Mainz in Germany, Sorbonne University in France, and the Facility for Rare Isotope Beams (FRIB) discuss the limit of the periodic table and revising the concept of the “island of stability” with recent advances in superheavy element research. Their work first appeared in Nature Reviews Physics.

In addition to the Nature Reviews Physics, Physics Reports has published a review on the atomic electronic structure theory for superheavy elements.

What is the heaviest bound nucleus and the heaviest bound atom and what are their properties? The nuclei of chemical elements with more than 103 protons are labeled as “superheavy.” They are part of a vast unknown territory of these nuclei that scientists are trying to uncover. Exploring this uncharted territory provides prospects for discoveries that connect the broad areas of science.

Mar 21, 2024

‘Dual-ligand’ strategy helps to achieve perfect asymmetric kinetic resolution polymerization

Posted by in categories: chemistry, energy

Studies on the synthesis and application of chiral materials has important scientific significance and market value. However, the design, synthesis and application of chiral materials are still in their infancy, and relevant research is limited to natural chiral polymer materials and very few artificial synthetic chiral materials.

In response to the key problems of synthesis, characterization, and mechanism research in the field of chiral materials, researchers from the Qingdao Institute of Bioenergy and Bioprocess Technology of the Chinese Academy of Sciences have proposed a novel concept of “asymmetric kinetic resolution polymerization” (AKRP), which provides a new method for the efficient synthesis, direct characterization of chiral polymer materials, and a new approach for studying the reaction mechanism of asymmetric polymerization.

The challenge in achieving AKRP is the design and of highly enantioselective catalysts. To solve this problem, the researchers proposed the “dual-ligand” strategy for the first time, enabling the highly enantioselective chiral (BisSalen)Al catalysts. The research is published in Journal of the American Chemical Society.

Mar 21, 2024

Scientists Find ‘Switch’ That Stops Immune System Attacking Healthy Cells

Posted by in categories: biotech/medical, chemistry

Our immune system is talented at telling the difference between the chemistry of our own body and that of an invading pathogen. When it malfunctions, our body can become host to an intense civil war.

Scientists are keen to understand this in more detail, and a newly identified ‘switch’ that deactivates a sensor of foreign DNA may provide important insight.

A key part of this discovery, made by a team from the Swiss Federal Institute of Technology Lausanne, is an enzyme called cyclic GMP-AMP synthase (cGAS).

Mar 21, 2024

Two ancient threads discovered in Milky Way galaxy named Shiva and Shakti

Posted by in categories: chemistry, space

Khyati Malhan of the Max Planck Institute for Astronomy (MPIA) in Heidelberg, Germany, who spearheaded the research, expressed astonishment at the ability to detect these ancient structures.

“The Milky Way has undergone profound changes since these stars were born. The fact that we can still recognize them as a group is truly amazing and a testament to the unprecedented data provided by Gaia,” Malhan stated.

The discovery was made possible through Gaia’s observations, which allowed researchers to determine the orbits, content, and composition of individual stars within the Milky Way. “Upon visualising the orbits of these stars, two new structures emerged, distinguished by their unique chemical composition. We named them Shakti and Shiva,” added Malhan.

Mar 21, 2024

Tiny magnetic implants enable wireless health monitoring when paired with wearable device

Posted by in categories: chemistry, computing, health, wearables

In a study published in the journal Science Advances, researchers from Peking University have unveiled a miniaturized implantable sensor capable of health monitoring without the need of transcutaneous wires, integrated circuit chips, or bulky readout equipment, thereby reducing infection risks, improving biocompatibility, and enhancing portability. The study is titled “Millimeter-scale magnetic implants paired with a fully integrated wearable device for wireless biophysical and biochemical sensing.”

Mar 20, 2024

China Room Temperature Superconductor Researcher Had Experiments to Refute Critics

Posted by in categories: chemistry, materials

Chinese researchers are making variations of LK99 room temperature superconductor materials with more sulfur and copper in the chemistry. They are publishing results with stronger magnetic indications of a Meissner effect.

The chinese researchers have been online discussing their room temperature superconducting research and the challenges of the materials.

Here are the issues discussed.

Mar 20, 2024

Can epigenetic reprogramming reverse aging?

Posted by in categories: biotech/medical, chemistry, genetics, life extension

The field of aging research has made significant progress over the last three decades, reaching a stage where we now understand the underlying mechanisms of the aging process. Moreover, the knowledge has broadened to include techniques that quantify aging, decelerate its process, as well as sometimes reverse aging.

To date, twelve hallmarks of aging have been identified; these include reduced mitochondrial function, loss of stem cells, increased cellular senescence, telomere shortening, and impaired protein and energy homeostasis. Biomarkers of aging help to understand age-related changes, track the physiological aging process and predict age-related diseases [1].

Longevity. Technology: Biological information is stored in two main ways, the genomes consisting of nucleic acids, and the epigenome, consisting of chemical modifications to the DNA as well as histone proteins. However, biological information can be lost over time as well as disrupted due to cell damage. How can this loss be overcome? In the 1940s, American mathematician and communications engineer Claude Shannon came up with a neat solution to prevent the loss of information in communications, introducing an ‘observer’ that would help to ensure that the original information survives and is transmitted [2]. Can these ideas be applied to aging?

Mar 19, 2024

New study uncovers how hydrogen provided energy at life’s origin

Posted by in categories: biological, chemistry, sustainability

Hydrogen gas is a clean fuel. It burns with oxygen in the air to provide energy with no CO2. Hydrogen is a key to sustainable energy for the future. Though humans are just now coming to realize the benefits of hydrogen gas (H2 in chemical shorthand), microbes have known that H2 is a good fuel for as long as there has been life on Earth. Hydrogen is ancient energy.

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