2,5-Dimethyl-furan (DMF) was electrochemically synthesized from 5-hydroxymethylfurfural with high efficiency and selectivity using a CuNi bimetallic electrode.

The aim of this study was to investigate the effects of oxygen and moisture content (MC) on the chemical and color changes of black locust (Robinia pseudoacacia) wood during heat treatment. The wood flour was conditioned to different initial MCs and heated for 24 h at a constant temperature of 120ºC in either oxygen or nitrogen atmosphere. The pH values and chromaticity indexes were examined. Diffuse reflectance UV-Vis (DRUV) and Fourier transform infrared (FTIR) spectra were used to characterize the changes of chromophores upon heating. The study demonstrated that the pH values decreased after heat treatment, and it was lower when the heat treated was in oxygen than in nitrogen. The L* decreased significantly, while a* and b* increased. The total color difference ΔE* increased with increasing initial MC until a plateau was reached after 30% MC. The color change was greater in oxygen than in nitrogen. The hydroxyl groups decreased after heat treatment. The releases of acid and formation of quinoid compounds and carboxylic groups during heat treatment were confirmed. Discoloration of wood is due mainly to the condensation and oxidation reactions, which are accelerated by oxygen. Higher MCs are required to obtain the greatest color change of wood in inert atmosphere.

The development of flexible sensors with low cost, facile preparation and good reproducibility is of profound significance for wearable electronics and intelligent systems. Lignin is an aromatic composition of lignocellulosic biomass and known as a cheap, renewable, and environmentally friendly resource available everywhere. In this study, we present a simple and low-cost approach for the preparation of a highly electrically sensitive and flexible composite with polydimethylsiloxane and carbonized lignin via a facile process (CL/PDMS). This electrically sensitive flexible composite can be used in the preparation of a piezo-resistive sensor, which exhibits stable and fast response to loading and unloading stress in 60 ms and 40 ms, respectively. The sensor prototype displayed high sensitivity (57 kPa⁻¹), wide range of working pressure (from 0 to 130 kPa) and excellent durability. The signals of pulse rates and the force needed for picking up items were successfully collected with this CL/PDMS sensor prototype. With the simple process for fabrication, low-cost of the filling material and excellent performance, we believe that the lignin-based sensitive flexible composite CL/PDMS is promising for applications in wearable electronics and intelligent systems such as health monitoring, smart skins, sports and other related areas.

Portable biosensors mainly focus on detecting biomarkers in biofluids but neglect the abundant skin biomarkers on the stratum corneum, which are associated with the functionality and integrity of the skin barrier. Here, we propose a sensing patch designed for direct sampling and in situ quantification of epidermal serine, an important biomarker for skin healthcare. The patch consists of a porous hydrogel for serine diffusion and ion conduction, and a molecular imprinted polymer-based electrochemical serine sensor. By integrating with a customized handheld serine tester, the serine sensing system enables in situ measurement of epidermal serine levels. We demonstrate the application of this serine sensing system in assessing the moisturizing effect of a skincare product and tracking the recovery progress of skin barrier function in a patient with atopic dermatitis. Our work opens up a potential application scenario for portable biosensors in personalized skin healthcare.

In situ synthesis of Ni _x Se _y –NiFe LDH core–shell nanoarrays on nickel foam for electrochemical oxidation of 5-hydroxymethylfurfural and furfural.