Electrospun VO2/carbon fibers for aqueous zinc-ion batteries

Aqueous zinc-ion batteries (AZIBs) have become one of the most potential energy storage devices due to their high safety and low cost. Vanadium oxide is an ideal cathode material for AZIBs because of its unique tunnel structure and multivalent nature. In this work, electrospun VO2/carbon fibers (VO2@CPAN) with a three-dimensional (3D) network are obtained by an electrospinning strategy combining with a controlled heat treatment. As cathode for AZIBs, the 3D network of the carbon fiber significantly improves the conductivity of VO2, avoids the agglomeration of VO2, and increases the stability of VO2. Therefore, VO2@CPAN delivers a specific capacity of 323.2 mA h g-1 at 0.2 A g-1, which is higher than pure VO2. At the same time, excellent capacity retention of 76.6% is obtained at high current density of 10 A g-1 after 3000 cycles.

Heat-killed endophytic bacterium induces robust plant defense responses against important pathogens

Stress caused by pathogens strongly damages plants. Developing products to control plant disease is an important challenge in sustainable agriculture. In this study, a heat-killed endophytic bacterium (HKEB), Bacillus aryabhattai, is used to induce plant defense against fungal and bacterial pathogens, and the main defense pathways used by the HKEB to activate plant defense are revealed. The HKEB induced high protection against different pathogens through the salicylic and jasmonic acid pathways. We report the presence of gentisic acid in the HKEB for the first time. These results show that HKEBs may be a useful tool for the management of plant diseases.

A water-soluble boronic acid sensor for caffeic acid based on double sites recognition

Due to reversibly and covalently binding with Lewis bases and polyols, boronic acid compounds as fluorescent sensors have been widely reported to recognize carbohydrates, ions, hydrogen peroxide, and so on. However, boronic acid sensors for highly selective recognition of caffeic acid rather than catechol or catechol derivatives have not been reported yet. Herein a novel water-soluble sensor 5c with double recognition sites based on a boronic acid was reported. When 2.3 × 10-4 M of caffeic acid was added, the fluorescence intensity of sensor 5c decreased by 99.6% via inner filter effect (IFE) because its excitation spectrum well overlaps with the absorption spectrum of caffeic acid under neutral condition, while the fluorescence increased or did not change obviously after binding with other analytes including carbohydrates and other catechol derivatives. In addition, the response time to caffeic acid is fast at room temperature, and a high binding constant (9245.7 ± 348.3 M-1) and low LOD (1.81 × 10-6 M) was calculated. Moreover, determination of caffeic acid content in caffeic acid tablets was studied, and the recovery rate is sufficient. Therefore, sensor 5c can be used as a potential tool for detecting biologically significant caffeic acid in real samples.