Photo-induced hydrophilicity at the ZnO(112̄0) surface: an evolutionary algorithm-aided density functional theory study.

Evolutionary algorithm-aided density functional theory calculations were utilized to determine the stable adsorption structures of H2O at ZnO(112̄0) extensively under different coverages. By decomposing the adsorption energetics, we illustrate that H2O dissociation to a large extent is actually hampered by the barrier for induced distortion of the ZnO surface, and once the surface becomes less difficult to be distorted it will exhibit higher hydrophilicity or even superhydrophilicity. Specifically, photo-stimulation modelling suggests that the surface Zn-O bonds can be weakened by photo-excitation, and the layer of fully dissociated H2O can be then facilitated to form. Accordingly, a novel mechanism for photo-induced superhydrophilicity is proposed.

Molybdenum sulfide Co-catalytic Fenton reaction for rapid and efficient inactivation of Escherichia coli.

As a typical advanced oxidation technology, the Fenton reaction has been employed for the disinfection, owing to the strong oxidizability of hydroxyl radicals (·OH). However, the conventional Fenton system always exhibits a low H2O2 decomposition efficiency, leading to a low production yield of ·OH, which makes the disinfection effect unsatisfactory. Herein, we develop a molybdenum sulfide (MoS2) co-catalytic Fenton reaction for rapid and highly efficient inactivation of Escherichia coli K-12 (E. coli) and Staphylococcus aureus (S. aureus). As a co-catalyst in the Fe(II)/H2O2 Fenton system, MoS2 can greatly facilitate the Fe(III)/Fe(II) cycle reaction by the exposed Mo4+ active sites, which significantly improves the H2O2 decomposition efficiency for the ·OH production. As a result, the MoS2 co-catalytic Fenton system can reach up to 83.37% of inactivation rate of E. coli just in 1 min and 100% of inactivation rate within 30 min, which increased by 2.5 times than that of the conventional Fenton reaction. Furthermore, the ·OH as the primary reactive oxygen species (ROS) in MoS2 co-catalytic Fenton reaction was measured and verified by electron paramagnetic resonance (EPR) and photoluminescence (PL). It is demonstrated an increased amount of ·OH generated from the decomposition of H2O2 in the presence of MoS2, which is responsible for the rapid and efficient inactivation of E. coli and S. aureus. This study provides a new perspective for rapid and highly efficient inactivation of bacteria in environmental remediation.

Double-diffusion-based synthesis of BiVO4 mesoporous single crystals with enhanced photocatalytic activity for oxygen evolution.

BiVO4 mesoporous single crystals (MSCs) were successfully prepared, for the first time, by a one-step hydrothermal method using the acidified BiVO4 precursor solution pre-impregnated silica as the template. It was revealed that the BiVO4 MSCs were formed by a double-diffusion mechanism. The O2 evolution rate over BiVO4 MSCs was improved nearly 10 times than that over BiVO4 bulk single crystals.

Ontogenetic expression and 17ß-estradiol regulation of immune-related genes in early life stages of Japanese medaka (Oryzias latipes).

Accumulating evidence suggests that environmental endocrine disrupting chemicals (EDCs) may exert adverse effects on aquatic organisms via the modulation of immune competence in addition to the endocrine system. However, to date, most studies have been undertaken only on biochemical and histopathological endpoints, and few studies have addressed the role of immune response gene transcript abundance in response to estrogen. In the present study, the ontogenetic expression of immune-related genes, including three complement components (C3-1, C3-2 and Bf/C2), two cytokines (IL-21 and type I IFN [IFN]), lysozyme (LZM), novel immune-type receptor (NITR-18), Ikaros (IK) and ceruloplasmin (CP) were characterized during different developmental periods (from 0 to 28 d post-hatch [dph]) in Japanese medaka. Furthermore, the responses of these genes to natural estrogen (i.e., 17ß-estradiol [E2]) were evaluated. E2 exposure at sublethal concentrations (0.1-10 µg/L) down-regulated the gene expression of C3-1, C3-2, Bf/C2, LZM and CP, while up-regulating the expression of IL-21, IFN, NITR-18 and IK. The results demonstrate a very different trend in gene expression in fish larvae exposed to E2 when compared with the ontogenetic changes in control, suggesting that exposure to environmental chemicals with estrogenic activities may interfere with immune-related genes and thus potentially influence the susceptibility of fish to opportunistic infections. These findings confirm the ability of exogenous estrogens to elicit changes in immune-related gene expression, and broaden our understanding about the mechanisms underlying the actions of EDCs. In addition, the expression profiles of immune-related genes can be developed for use as biomarkers for future immunotoxicological studies.