Reflecting on the LK-99 fervour: insights and future prospects.

A Copper-substituted lead apatite, named LK-99 by its authors, has recently emerged as a candidate for the world's first ambient-conditions superconductor, but has since not demonstrated the anticipated properties when subject to independent scrutiny. In this review we cover the experimental and theoretical studies that have been dedicated to this unusual material, while briefly discussing the original arXiv papers. So far, all the synthesis methods result in the formation of a multiphase material with unpredictable structure and unstable stoichiometry.

Spectral Investigations of 60S Bioactive Glass Modified with La and Y Ions.

The changes in the atomic structure and in the network of bonds between oxide tetrahedra in 60S bioactive glass upon modification of its structure by yttrium and lanthanum atoms were investigated via XPS, FTIR, and NMR spectroscopy methods. The presence of nanostructure in the samples of 60S bioactive glass modified with yttrium and lanthanum was demonstrated. The formation of a bioinert core of 60S bioactive glass nanoparticles with the subsequent formation of a biocompatible layer is facilitated by the redistribution of electron density when oxygen bridge bonds are broken, PO and SiO tetrahedra are fragmented in the polymer matrix, and isolated nanoclusters are formed.