Synthesis of Thermally Stable and Highly Luminescent Cs5Cu3Cl6I2 Nanocrystals with Nonlinear Optical Response

Low-dimensional Cu(I)-based metal halide materials are gaining attention due to their low toxicity, high stability and unique luminescence mechanism, which is mediated by self-trapped excitons (STEs). Among them, Cs₅Cu₃Cl₆I₂, which emits blue light, is a promising candidate for applications as a next-generation blue-emitting material. In this article, an optimized colloidal process to synthesize uniform Cs₅Cu₃Cl₆I₂ nanocrystals (NCs) with a superior quantum yield (QY) is proposed. In addition, precise control of the synthesis parameters, enabling anisotropic growth and emission wavelength shifting is demonstrated. The synthesized Cs₅Cu₃Cl₆I₂ NCs have an excellent photoluminescence (PL) retention rate, even at high temperature, and exhibit high stability over multiple heating–cooling cycles under ambient conditions. Moreover, under 850-nm femtosecond laser irradiation, the NCs exhibit three-photon absorption (3PA)-induced PL, highlighting the possibility of utilizing their nonlinear optical properties. Such thermally stable and highly luminescent Cs₅Cu₃Cl₆I₂ NCs with nonlinear optical properties overcome the limitations of conventional blue-emitting nanomaterials. These findings provide insights into the mechanism of the colloidal synthesis of Cs₅Cu₃Cl₆I₂ NCs and a foundation for further research.     

Structural Characterization and Extended Substrate Scope Analysis of Two Mg2+-Dependent O-Methyltransferases from Bacteria**

Oxygen-directed methylation is a ubiquitous tailoring reaction in natural product pathways catalysed by O-methyltransferases (OMTs). Promiscuous OMT biocatalysts are thus a valuable asset in the toolkit for sustainable synthesis and optimization of known bioactive scaffolds for drug development. Here, we characterized the enzymatic properties and substrate scope of two bacterial OMTs from Desulforomonas acetoxidans and Streptomyces avermitilis and determined their crystal structures. Both OMTs methylated a wide range of catechol-like substrates, including flavonoids, coumarins, hydroxybenzoic acids, and their respective aldehydes, an anthraquinone and an indole. One enzyme also accepted a steroid. The product range included pharmaceutically relevant compounds such as (iso)fraxidin, iso(scopoletin), chrysoeriol, alizarin 1-methyl ether, and 2-methoxyestradiol. Interestingly, certain non-catechol flavonoids and hydroxybenzoic acids were also methylated. This study expands the knowledge on substrate preference and structural diversity of bacterial catechol OMTs and paves the way for their use in (combinatorial) pathway engineering.     

Geotechnical properties of problematic expansive subgrade stabilized with guar gum biopolymer

Clean Technologies and Environmental Policy - This article presents a comprehensive study on the geotechnical behavior of problematic expansive subgrade stabilized by guar gum (GG) biopolymer. In...     

Tough,Bio-disintegrable and Stretchable Substrate Reinforced with Nanofibers for Transient Wearable Electronics

Research on transient wearable electronics with stretchable components is of increasing interest because of their abilities to conform seamlessly to human tissues and, more interestingly, disappear from the environment when disposed. To wear them comfortably, their component materials must be pliable, tough, stretchable, biocompatible, and disintegrable. However, most biodegradable materials are not stretchable or tough, limiting their use in transient wearable electronics. Herein, these challenges are addressed by demonstrating a biodegradable nanofiber (NF)-reinforced water-borne polyurethane (NFR-WPU) with stretchability, toughness, and partial biodegradability by embedding biodegradable composite NFs of poly(glycerol sebacate): poly(vinyl alcohol) (PGS:PVA) into the WPU matrix, thus rendering its properties tunable. An optimal loading amount of NFs into the NFR-WPU significantly enhanced the toughness by 19 times while maintaining the Young's modulus as low as 3.3 MPa. Furthermore, the NFR-WPU substrate has very high fracture toughness and shows excellent biocompatibility. Moreover, the NFR-WPU has a disintegration rate nine times greater than that of pristine WPU. Finally, disintegrable and stretchable triboelectric and capacitive touch sensors on the NFR-WPU are fabricated and demonstrated for potential use in transient wearable electronics.