The variation of five antibiotic resistance genes (ARGs)-tetG, tetW, tetX, sul1, and intI1-in a full-scale municipal wastewater treatment plant with A(2)O-MBR system was studied. The concentrations of five resistance genes both in influent and in membrane bioreactor (MBR) effluent decreased as sul1 > intI1 > tetX > tetG > tetW, and an abundance of sul1 was statistically higher than three other tetracycline resistance genes (tetG, tetW, and tetX) (p < 0.05). The concentrations of five ARGs in the influent were all higher in spring (median 10(5.81)-10(7.32) copies mL(-1)) than they were in other seasons, and tetW, tetX, and sul1 reached its lowest concentration in autumn (10(4.61)-10(6.81) copies mL(-1)). The concentration of ARGs in wastewater decreased in the anaerobic effluent and anoxic effluent, but increased in the aerobic effluent, and then sharply declined in the MBR effluent. The reduction of tetW, intI1, and sul1 was all significantly positively correlated with the reduction of 16S ribosomal DNA (rDNA) in the wastewater treatment process (p < 0.01). The concentration of ARGs (copies mg(-1)) in sludge samples increased along the treatment process, but the abundance of five ARGs (ratio of ARGs to 16S rDNA) remained the same from anaerobic to anoxic to aerobic basins, while an increment ratio in MBR was observed for all ARGs.

The interfacial interaction of the colloidal NPs in solution is closely related to the surface charge, which heavily influences the NP synthesis, colloidal stabilization and various applications. [2] In general, the inorganic core of colloidal NPs in solutions possess a net electric charge at the interface, which can attract dissolved heterogeneously-charged crystal-constituting ions and solvent molecules by electrostatic interaction, thus constructing the electrical double layer and rendering the NPs well-dispersed (Figure 1a). The presence of surface charge can also physically or chemically adsorb the dissolved molecules such as organic dyes at the NP interface, which restructures the energy dissipation pathways between the colloidal NPs and outside world. However, although much efforts had been devoted to understanding the interfacial interactions of NPs, comparable study taking into account the motion states of the particles is still rare. For example, the colloidal NPs could experience Brownian motion in stationary solution, flowing in fluid, as well as keeping static when being adhered on macroscopic objects, depending on the specific environments in applications such as biodetection, bioimaging, and printable electronics. [3] Albeit of its fundamental importance, the specific role of particle moving on the interfacial reactions of colloidal NPs is ambiguous up to now and as always been ignored for most cases.The sum frequency generation (SFG) vibrational spectroscopy, a second-order nonlinear optical technique, has been proved to be powerful for probing the interfacial molecules in view of its inherent interface selectivity and high sensitivity. [4] In this work, combined in situ spectroscopies based on SFG and photoluminescence (PL) characterization were adopted to reveal the unprecedented effect of particle moving to the interfacial adsorption of colloidal fluoride nanocrystals in great detail. Comparative results of the proof-of-concept experiments for the ligand-free NaYF 4 :Yb,Er upconverting (UC) nanocrystals reveal that the particle moving in aqueous solution reversibly alter the surface charge. More importantly, it is found that the motion state of the NPs determines molecular arrangement of Rhodamine B (RhB) at the particle interface, which significantly affect the energy transfer from the colloidal NPs to the adsorbed dyes.

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To understand the transport and fate of antibiotic resistance genes in wastewater treatment plants, 12 resistance genes (ten tetracycline resistance genes, two sulfonamides genes) and class 1 integron gene (intI1) were studied in five wastewater treatment plants with different treatment processes and different sewage sources. Among these resistance genes, sulfonamides genes (sul1 and sul2) were of the most prevalent genes with detection frequency of 100%. The effluent water contained fewer types of resistance genes than the influent in most selected plants. The abundance of five quantified resistance genes (tetG, tetW, tetX, sul1, and intI1) decreased in effluent of plants treating domestic or industrial wastewater with anaerobic/aerobic or membrane bioreactor (MBR) technologies, but tetG, tetX, sul1, and intI1 increased along the treatment units of plants treating vitamin C production wastewater by anaerobic/aerobic technology. In plant treating cephalosporins production wastewater by UASB/aerobic process, the quantities of tetG, tetX, and sul1 first decreased in anaerobic effluent water but then increased in aerobic effluent water.