Phys.org October 31, 204 One hundred years ago, Julius Bredt published an observation that certain molecules that constrained several adjacent carbon centers in a particular nonplanar arrangement could not form double bonds between them. These hypothetical double bonds became known as “anti-Bredt” olefins, and the doctrine that they were inaccessible remains widespread even with the occasional hint to the contrary. Researchers at UCLA reported a general strategy to prepare these olefins as fleeting intermediates that could be captured in cycloaddition reactions. The protocol relies on the driving force of silicon-fluorine bond formation from a precursor, which is akin to approaches […]
Discovery challenges existing theories of magnetism in kagome metals
Phys.org October 30, 2024 The rare earth RMn6Sn6 (R = rare earth) family magnetic kagome systems, where their kagome flat bands are calculated to be near the Fermi level in the paramagnetic phase have been reported. While partially filling a kagome flat band is predicted to give rise to a Stoner-type ferromagnetism, experimental visualization of the magnetic splitting across the ordering temperature has not been reported for any of these systems leaving the nature of magnetism in kagome magnets an open question. An international team of researchers (USA – Rice University, Brookhaven National Lab, Los Alamos National Laboratory, Israel, Czech Republic) probed […]
Engineered bacterial protein offers efficient rare earth metal separation
Phys.org October 28, 2024 Elucidating details of biology’s selective uptake and trafficking of rare earth elements, particularly the lanthanides, has the potential to inspire sustainable biomolecular separations of these essential metals for many modern technologies. Researchers at The Pennsylvania State University biochemically and structurally characterized Methylobacterium (Methylorubrum) extorquens LanD from a bacterial gene cluster for lanthanide uptake. The protein provided only four ligands at its surface-exposed lanthanide-binding site, allowing for metal-centered protein dimerization that favored the largest lanthanide, LaIII. Selective dimerization enriched high-value PrIII and NdIII relative to low-value LaIII and CeIII in an all-aqueous process, achieved higher separation factors […]
Melting Arctic sea-ice could affect global ocean circulation, study warns
Phys.org October 27, 2024 The Last Interglacial period (LIG) was characterized by a long-term Arctic atmospheric warming above the preindustrial level. The LIG thus provides a case study of Arctic feedback mechanisms of the cryosphere-ocean circulation-climate system under warm climatic conditions. Previous studies suggested a delay in the LIG peak warming in the North Atlantic compared to the Southern Ocean and evoked the possibility of southward extension of Arctic Sea ice to the southern Norwegian Sea during the early LIG. An international team of researchers (Norway, Germany) compiled new and published proxy data on past changes in sea ice distribution, […]
MXene nanomaterials enable wireless charging in textiles
Nanowerk October 31, 2024 Due to their high conductivity, electrochemically active surface, and ability to produce additive-free coatings from aqueous inks, MXenes are an ideal material to integrate into textiles to add functionality as well as generate and store electrical energy. A team of researchers in the US (Drexel University, industry, University of Pennsylvania, Veterans Affairs Medical Center, Philadelphia) integrated MXenes into wireless charging coils printed onto textiles, serving as a conductive adhesive between MXene textile components. The MXene coils could power MXene-textile supercapacitors, allowing electromyography measurements with epidermal MXene electrodes and active heating with printed MXene-textile filaments. The on-garment […]
New machine learning model quickly and accurately predicts dielectric function
Phys.org October 25, 2024 Fast and accurate prediction of dielectric function facilitates the development of novel dielectric materials, an ingredient of many cutting-edge technologies such as 6G networks. Researchers in Japan introduced a versatile machine-learning scheme implemented in Git hub for predicting dipole moments of molecular liquids to study dielectric properties. They attributed the center of mass of Wannier functions (called Wannier centers), to each chemical bond and created neural network models. They applied liquid methanol and ethanol to demonstrate that their neural network models successfully predicted the dipole moment of various liquid configurations in close agreement with DFT calculations. […]
New method successfully recycles carbon fiber composite into reusable materials
Phys.org October 31, 2024 Carbon fiber reinforced polymers (CFRPs, or composites) are increasingly replacing traditional manufacturing materials used in the automobile, aerospace, and energy sectors. With this shift, a team of researchers in the US (University of Southern California, University of Kansas) developed an end-of-life processes for CFRPs and demonstrated a strategy to upcycle pre- and postconsumer polystyrene-containing CFRPs, cross-linked with unsaturated polyesters or vinyl esters, to benzoic acid. The thermoset matrix was upgraded via biocatalysis utilizing an engineered strain of the filamentous fungus Aspergillus nidulans, which gave access to valuable secondary metabolites in high yields. Reactions were engineered to […]
New partially coherent unidirectional imaging system enhances visual data transmission
Phys.org October 28, 2024 Unidirectional imagers form images of input objects only in one direction. Researchers at UCLA reported unidirectional imaging under spatially partially coherent light and demonstrated high-quality imaging only in the forward direction (A → B) with high power efficiency while distorting the image formation in the backward direction (B → A) along with low power efficiency. Their analyses revealed that when illuminated by a partially coherent beam with a correlation length of ≥∼1.5λ, where λ was the wavelength of light, diffractive unidirectional imagers achieved robust performance, exhibiting asymmetric imaging performance between the forward and backward directions. A […]
Quantum simulator could help uncover materials for high-performance electronics
Phys.org October 30, 2024 Arrays of coupled superconducting qubits natively emulate the dynamics of interacting particles according to the Bose–Hubbard model. However, many interesting condensed-matter phenomena emerge only in the presence of electromagnetic fields. A team of researchers in the US (MIT, MIT Lincoln Laboratory) emulated the dynamics of charged particles in an electromagnetic field using a superconducting quantum simulator. They produced a broadly adjustable synthetic magnetic vector potential by applying continuous modulation tones to all qubits. The synthetic vector potential obeyed the required properties of electromagnetism… read more. TECHNICAL ARTICLE
Scientists discover molecules that store much of the carbon in space
MIT News October 24, 2024 Polycyclic aromatic hydrocarbons (PAHs) are organic molecules containing adjacent aromatic rings. Infrared emission bands show that PAHs are abundant in space, but only a few specific PAHs have been detected in the interstellar medium. An international team of researchers (USA – MIT, University of Michigan, Worcester State University, NASA Goddard Space Flight Center, Harvard Smithsonian, National Radio Astronomy Observatory, Virginia Military Institute, University of Virginia, Canada) detected 1-cyanopyrene, a cyano-substituted derivative of the related four-ring PAH pyrene, in radio observations of the dense cloud TMC-1. They estimated that pyrene contains up to 0.1% of the […]