46 research outputs found

    Long-Term Effects of Copper Nanoparticles on Wastewater Biological Nutrient Removal and N<sub>2</sub>O Generation in the Activated Sludge Process

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    The increasing use of copper nanoparticles (Cu NPs) raises concerns about their potential toxic effects on the environment. However, their influences on wastewater biological nutrient removal (BNR) and nitrous oxide (N<sub>2</sub>O) generation in the activated sludge process have never been documented. In this study the long-term effects of Cu NPs (0.1–10 mg/L) on BNR and N<sub>2</sub>O generation were investigated. The total nitrogen (TN) removal was enhanced and N<sub>2</sub>O generation was reduced at any Cu NPs levels investigated, but both ammonia and phosphorus removals were not affected. The mechanism studies showed although most of the Cu NPs were absorbed to activated sludge, the activated sludge surface was not damaged, and the released copper ion from Cu NPs dissolution was the main reason for TN removal improvement and N<sub>2</sub>O reduction. It was also found that the transformation of polyhydroxyalkanoates and the activities of ammonia monooxygenase, nitrite oxidoreductase, exopolyphosphatase, and polyphosphate kinase were not affected by Cu NPs, whereas the decreased metabolism of glycogen and the increased activities of denitrification enzymes were observed. Further investigation revealed that Cu NPs increased the number of denitrifiers (especially N<sub>2</sub>O reducing denitrifiers) but decreased nitrite accumulation. All these observations were in correspondence with the enhancement of TN removal and reduction of N<sub>2</sub>O generation

    Additional file 2: Table S1. of The process-related dynamics of microbial community during a simulated fermentation of Chinese strong-flavored liquor

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    Good coverages of prokaryotic Sequencing (16S rRNA gene). Table S2. Good coverages of eukaryotic Sequencing (ITS gene). Table S3. The OTU BLAST result based on 16S rRNA gene. Table S4. The OTU BLAST result based on ITS region. (PDF 309 kb

    Steady-state level of key glycolytic genes.

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    <p><b><i>A</i></b>, northern blot analysis of <i>HXK2</i>, <i>PFK1</i> and <i>PYK1</i> transcription levels. The nuclear encoded 25S rRNA was hybridized as an internal control. <b><i>B</i></b>, relative expression levels of these genes were calculated by three determinations. <b><i>C</i></b>, translational levels of hexokinase in each strain, tubulin was as an internal control. <b><i>D</i></b>, calculation of the relative expression level of hexokinase.</p

    Preoperative contrast sensitivity (log<sub>10</sub>)<sup>a</sup>.

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    <p>Preoperative contrast sensitivity (log<sub>10</sub>)<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0182251#t003fn002" target="_blank"><sup>a</sup></a>.</p

    <i>In vivo</i> staining of the mitochondrion to measure the membrane potential by Rhodamine 123 dyes.

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    <p>2×10<sup>6</sup> cells in 1 ml supernatant were incubated with Rhodamine 123 (5 µg/ml) for 20 min at 30°C. Cell pellets were resuspended in 20 µl PBS and visualized with Carl Zeiss 710 LSM microscopy. The relative fluorescence signal of each strain is shown in the right panel.</p

    Rough Glass Surface-Mediated Transition of Micelle-to-Vesicle in Sodium Dodecylbenzenesulfonate Solutions

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    In this paper, we report a micelle-to-vesicle transition in aqueous solution of the anionic single-tailed surfactant (STS) sodium dodecylbenzenesulfonate (SDBS), with the mediation of a rough glass surface (RGS) in the absence of cosurfactants or additives. This transition produced a mixed solution of vesicles and micelles. Interestingly, the obtained SDBS vesicles in the solution displayed good stability during a long-term storage (at least 6 months at room temperature), exposure to high temperature (80 °C for 2 h), and freeze–thawing (−20 or −196 °C for 2 h to approximately 25 °C) after the RGS was removed. Our results confirmed that SDBS could adsorb on the RGS to form bilayers, in which the molecular packing parameter of SDBS was in the range of 1/2–1. The bilayer adsorption and the roughness of the solid surface played an important role in the vesicle formation. In addition, we propose a possible mechanism for the RGS-mediated transition of micelle-to-vesicle in SDBS solutions: SDBS micelles and molecules adsorb on the RGS to form curved bilayers; the curved bilayers detach from the RGS, and then close to form vesicles

    Rough Glass Surface-Mediated Formation of Vesicles from Lauryl Sulfobetaine Micellar Solutions

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    We report novel vesicles composed of the zwitterionic surfactant lauryl sulfobetaine (LSB), which is a simple single-tailed surfactant (STS). The novel vesicles spontaneously formed from LSB micellar solutions with the mediation of a rough glass surface (RGS) in the absence of any cosurfactants or additives. Importantly, the obtained STS vesicles displayed good stability upon long-term storage, exposure to high temperature, and freeze–thawing after the RGS was removed. The pH of the LSB solution (4.0–9.0) and the presence of NaCl (1.0 × 10<sup>–5</sup> and 1.0 × 10<sup>–4</sup> mol/L) in the LSB solution had no obvious influence on the formation and stability of the vesicles. The adsorption configuration of LSB on the RGS was investigated via water contact angle measurements and atomic force microscope observations. The results showed that LSB adsorption bilayers could form on the RGS, and the bilayer adsorption of LSB on the RGS and the roughness of the solid surface played a key role in the vesicle formation. A possible mechanism for the RGS-mediated formation of LSB vesicles is proposed: LSB micelles and molecules adsorb on the RGS to form curved bilayers, and the curved bilayers are then detached from the RGS and close to form vesicles. To the best of our knowledge, this is the first report of LSB alone forming vesicles. This finding extends our understanding of the nature of vesicle systems

    Demographic data one year postoperatively<sup>a</sup>.

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    <p>Demographic data one year postoperatively<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0182251#t002fn002" target="_blank"><sup>a</sup></a>.</p

    Growth activities of different yeast strains.

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    <p><b><i>A</i></b>, Series dilutions of each strain were spotted onto a 2% glucose medium (YPD) and the plate was incubated at 30°C for 72 hours. <b><i>B</i></b>, Growth curves analysis of yeast strains in the absence of neomycin in 20 hours. <b><i>C</i></b>, Growth activities of each strain when grown on medium containing neomycin after 72 hours incubation. <b><i>D</i></b>, Growth curves of strains cultured in YPD containing 32 µg/ml neomycin.</p
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