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In the present paper, single-crystal PbMoO4 nanorods and nanowires were synthesized via a simple sonochemical process without any templates or surfactants for the first time. The samples were analyzed by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and electron diffraction (ED). Experimental results indicated that the obtained PbMoO4 nanowires were single-crystal in structure and the aspect ratio was about 200. The pH value and precursor were found to be critical factors to the controlled preparation of PbMoO4 nanorods and nanowires. The possible mechanism for the synthesis of PbMoO4 nanorods and nanowires was also discussed and other one-dimensional nanomaterials can also be successfully prepared by the present method. [ABSTRACT FROM AUTHOR]

Aeromonas hydrophila is one of the important pathogenic bacteria in aquaculture causing serious losses every year. Essential oils are usually used as natural antimicrobial agents to reduce or replace the use of antibiotics. The aim of this study was to evaluate the antibacterial activity and explore the mechanisms of essential oil from satsuma mandarin (Citrus unshiu Marc.) (SMEO) against A. hydrophila. The results of the gas chromatography-mass spectrometer demonstrated that SMEO contains 79 chemical components with the highest proportion of limonene (70.22%). SMEO exhibited strong antibacterial activity against A. hydrophila in vitro , the diameter of the inhibition zone was 31.22 ± 0.46 mm, and the MIC and MBC values were all 1% (v/v). Intracellular material release, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and flow cytometry analysis revealed the dynamic antibacterial process of SMEO, the morphological changes of bacterial cells, and the leakage process of intracellular components. These results demonstrated that SMEO disrupted the extracellular membrane permeability. Our study demonstrated that SEMO has the potential to be used to control and prevent A. hydrophila infections in aquaculture. [ABSTRACT FROM AUTHOR]

The unreliable durability of high temperature proton exchange membrane fuel cells (HT-PEMFCs) is one of the restriction factors upon the commercialization process. In this paper, 600-h accelerated stress tests (ASTs) were performed on HT-PEMFCs to investigate the performance degradation under start/stop, load cycling (0.2–0.8 A cm−2 and 0.04–0.2 A cm−2) conditions. The activation, ohmic and mass transport polarization losses were determined in combination with the electrochemical impedance spectroscopy (EIS) and Tafel slope analysis, and the degradation modes such as carbon corrosion, catalyst degradation, acid loss and membrane degradation were analyzed by linear sweep voltammetry (LSV), cyclic voltammetry (CV) and transmission electron microscopy (TEM) characterization. The polarization curves of ASTs show that load cycling between 0.04 and 0.2 A cm−2 extensively aggravates performance degradation, indicating that high-potential operation has the greatest detrimental impact on the durability. By comparing the changes of the activation, ohmic and mass transport polarization losses, it can be found that the activation polarization is the dominant factor leading to performance degradation in the 600-h test, and the ohmic polarization has little effect on the performance degradation. After the test at load cycling between 0.2 and 0.8 A cm−2, the membrane is seriously degraded and the ohmic resistance increases significantly, and the severe acid loss becomes critical issue in the long-term durability of HT-PEMFC. • Activation, ohmic and mass transfer polarization losses are determined. • Activated polarization accounts for the largest proportion in the short term test. • Acid loss seriously affects the long term durability of HT-PEMFC. [ABSTRACT FROM AUTHOR]