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Category: chemistry – Page 140

Study offers new insights into understanding and controlling tunneling dynamics in complex molecules

Tunneling is one of most fundamental processes in quantum mechanics, where the wave packet could traverse a classically insurmountable energy barrier with a certain probability.

On the , effects play an important role in , such as accelerating enzyme catalysis, prompting spontaneous mutations in DNA and triggering olfactory signaling cascades.

Photoelectron tunneling is a key process in light-induced , charge and energy transfer and radiation emission. The size of optoelectronic chips and other devices has been close to the sub-nanometer atomic scale, and the quantum tunneling effects between different channels would be significantly enhanced.

Cells’ electric fields keep nanoparticles at bay, scientists confirm

The humble membranes that enclose our cells have a surprising superpower: They can push away nano-sized molecules that happen to approach them. A team including scientists at the National Institute of Standards and Technology (NIST) has figured out why, by using artificial membranes that mimic the behavior of natural ones. Their discovery could make a difference in how we design the many drug treatments that target our cells.

The team’s findings, which appear in the Journal of the American Chemical Society, confirm that the powerful electrical fields that cell membranes generate are largely responsible for repelling nanoscale particles from the surface of the cell.

This repulsion notably affects neutral, uncharged nanoparticles, in part because the smaller, charged the attracts crowd the membrane and push away the larger particles. Since many drug treatments are built around proteins and other nanoscale particles that target the membrane, the repulsion could play a role in the treatments’ effectiveness.

The Periodic Table Just Got a Cheat Sheet: Discover the Ten Electron Rule

The ‘ten electron’ rule provides guidance for the design of single-atom alloy catalysts for targeted chemical reactions.

A collaborative team across four universities have discovered a very simple rule to design single-atom alloy catalysts for chemical reactions. The ‘ten electron rule’ helps scientists identify promising catalysts for their experiments very rapidly. Instead of extensive trial and error experiments of computationally demanding computer simulations, catalysts’ composition can be proposed simply by looking at the periodic table.

Single-atom alloys are a class of catalysts made of two metals: a few atoms of reactive metal, called the dopant, are diluted in an inert metal (copper, silver, or gold). This recent technology is extremely efficient at speeding up chemical reactions but traditional models don’t explain how they work.

Microgravity Masters: Expedition 70 and Ax-3 Crews Working Together on Space Station

Eleven astronauts and cosmonauts from around the world are living and working together aboard the International Space Station (ISS) today, January 22. The four Axiom Mission 3 (Ax-3) private astronauts met the seven Expedition 70 crew members on Saturday beginning two weeks of dual operations.

The Ax-3 crew spent the weekend getting familiar with space station systems and emergency procedures before starting Monday with a full schedule of science and media activities. Ax-3 Commander Michael López-Alegría joined Pilot Walter Villadei and studied how microgravity affects the biochemistry of neurodegenerative diseases such as Alzheimer’s to improve health on Earth and in space. The duo later inserted samples into a fluorescence microscope for a study seeking to prevent and predict cancer diseases to protect crews in space and humans on Earth.

New Superconductor With Highest Critical Current for Its Type of Superconductor

A research team from Hefei Institutes of Physical Science (HFIPS), Chinese Academy of Sciences (CAS), discovered a new superconducting material called (InSe2)xNbSe2, which possesses a unique lattice structure. The superconducting transition temperature of this material reaches 11.6 K, making it the transition metal sulfide superconductor with the highest transition temperature under ambient pressure.

TMD materials have received lots of attention due to the numerous applications in the fields of catalysis, energy storage, and integrated circuit. However, the relatively low superconducting transition temperatures of TMD superconductors have limited their potential use.

In this study, scientists successfully fabricated a new superconducting material with the chemical formula (InSe2)xNbSe2. Unlike the conventional conditions where isolated atoms are inserted into the van de Waals gaps of low dimensional materials, in (InSe2)xNbSe2 the intercalated indium atoms were found to form InSe2-bonded chains.

Chinese Breakthrough: Revolutionary Superconducting Material With Record-Breaking Properties

A breakthrough discovery of a new superconducting material sets a new record for transition metal sulfide superconductors with a transition temperature of 11.6 K and a high critical current density, marking a significant advancement in superconductor development.

With the support of electrical transport and magnetic measurement systems of Steady High Magnetic Field Facility (SHMFF), a research team from Hefei Institutes of Physical Science (HFIPS), Chinese Academy of Sciences (CAS), discovered a new superconducting material called (InSe2)xNbSe2, which possesses a unique lattice structure. The superconducting transition temperature of this material reaches 11.6 K, making it the transition metal sulfide superconductor with the highest transition temperature under ambient pressure.

The results were published in the Journal of the American Chemical Society.

Chemists tie a knot using only 54 atoms

A trio of chemists at the Chinese Academy of Sciences’ Dalian Institute of Chemical Physics, working with a colleague from the University of Western Ontario, has tied the smallest knot ever, using just 54 atoms. In their study, published in the journal Nature Communications, Zhiwen Li, Jingjing Zhang, Gao Li and Richard Puddephatt accidentally tied the knot while trying to create metal acetylides in their lab.

The researchers were attempting to create types of alkynes called metal acetylides as a means to conduct other types of organic reactions. More specifically, they were attempting to connect carbon structures to gold acetylides—typically, such work results in the creation of simple chains of gold known as caternames.

But, unexpectedly, the result of one reaction created a chain that knotted itself into a trefoil knot with no loose ends. Trefoil knots are used in making pretzels and play a major role in . The researchers noted that the knot had a backbone crossing ratio (BCR) of 23. Knot BCRs are a measure of the strength of the knot. Most organic knots, the team notes, have a BCR somewhere between 27 and 33.