-
Gentry Munksgaard posted an update 1 month, 2 weeks ago
It can thus be concluded that high DO concentration during the algal bloom promoted the CH4 consumption by enhancing sediment CH4 oxidation, while algal-linked oxic water CH4 production as a major component of water CH4 promoted the CH4 emissions from the river. Our study highlights the regulation of Spirogyra in aquatic CH4 fluxes and will help to estimate accurately CH4 emissions from eutrophic rivers with dense blooms of filamentous green algae. Graphical abstract.The present work investigates the use of Agave americana fibers (AGF) as a precursor for activated carbon (AC) preparation via chemical activation using phosphoric acid (H3PO4), and the study of the influence of the preparation conditions on the adsorption capacity of the prepared AC toward Alpacide Yellow (AY). The preparation experiments have been conducted at different impregnation ratios acid/AGF (20 g/1 g, 30 g/1 g, and 40 g/1 g) with varied impregnation times (2 h, 4 h, and 6 h) and at different carbonization temperatures (200 °C, 400 °C, and 600 °C). The impregnation ratio of 40 g/1 g, the impregnation time of 6 h, and the carbonization temperature of 400 °C were selected as the optimal conditions for the preparation of AC with enhanced properties. Despite its low specific surface area (25 m2/g), the prepared AC showed a higher adsorption capacity toward AY (5.71 mg/g) as compared with that of the commercial activated carbon (CC) (5.27 mg/g) which showed a higher specific surface area (825 m2/g). This could be due to the existence of pores and functional groups on the surface of AC, as evidenced by the analysis results of FTIR, DSC, and SEM. The adsorption process was found fast and fractal since it followed the kinetic model of the Brouers-Sotolongo fractal (BSf) (R2 = 0.999), while the mathematical modeling of the adsorption isotherm of AY on the synthesized AC was stochastic since it followed the General Brouers-Sotolongo (GBS) (R2 = 0.999).Azoles, the antifungal pharmaceuticals are emerging as a new class of water contaminants with a potential to influence the endocrine physiology of surrounding aquatic fauna. In this study, we made an attempt to assess the relative efficacy of widely used azoles belonging to two subclasses, i.e., (i) triazoles (letrozole, fluconazole, itraconazole) and (ii) imidazoles (ketaconazole, ornidazole, clotrimazole), on the onset of germinal vesicle breakdown (GVBD) (an initial step in the final maturation of oocytes) in fully grown preovulatory oocytes of zebrafish (Danio rerio) using an in vitro model. Oocytes (> 650 μm) isolated manually from gravid ovaries were exposed to (i) 0.01 and/or 0.1, 1.0, 5.0, 10, 15, and 20 ng/ml and (ii) 1.0, 2.0, 3.0, 4.0, and 5.0 μg/ml of drugs. Zebrafish Ringer’s solution (vehicle) and 0.01% ethyl alcohol (solvent) were used as negative controls. 17α, 20 β-Dihydroxy-4-pregnen-3-one (17α-DHP) and diethylstibestrol (DES), potent inducers of GVBD in fish, were used as positive controls. GVBD was scored hourly from 0-6 h. In negative controls, there were no indications of GVBD even at the 6th hour, while in 17α-DHP- and DES-exposed oocytes, GVBD was initiated from the 1st hour, reaching 80% and 76% respectively at the 6th hour. Among azoles, letrozole induced GVBD in 73-85%, fluconazole (30-33%), itraconazole (23-33%), ketaconazole (46-53%), ornidazole (36-40%), and clotrimazole (30-33%) of oocytes. These results suggest that azole pharmaceuticals induce GVBD in fish oocytes that may be attributed to their variable degree of cytochrome P450 enzyme inhibitor activity.Herein we synthesized a novel structure of mesoporous TiO2 decorated on 1D ZnO nanorods for environmental remediation. The effect of mesoporous TiO2 over 1D nanorods were investigated. The phase transitions of nanocomposite were confirmed by powder diffraction analysis. The morphological investigation of synthesized TiO2/ZnO catalyst revealed that the TiO2 are in porous in nature which covered the surface of 1D nanorods. The size of mesoporous TiO2 nanoparticles was about 10-15 nm. The chemical composition and elemental mapping results clearly evident that the presence of ZnO and TiO2 is distributed uniformly on ZnO nanorods. TiO2/ZnO nanocomposite shows enhanced activity which degrades in 14 min under visible light irradiation. TiO2/ZnO catalyst with 5 wt % exhibited the high photocatalytic activity (0.1882 min-1). It is proposed that a synergistic interaction between ZnO and TiO2 leads to a charge separation which leads to the enhanced activity.Drought is a major natural disaster that significantly impacts the susceptibility and flexibility of the ecosystem by changing vegetation phenology and productivity. This study aimed to investigate the impact of extreme climatic variation on vegetation phenology and productivity over the four sub-regions of China from 2000 to 2017. Daily rain gauge precipitation and air temperature datasets were used to estimate the trends, and to compute the standardized precipitation-evapotranspiration index (SPEI). Remote sensing-based Enhanced Vegetation Index (EVI) data from a moderate resolution imaging spectroradiometer (MODIS) was used to characterize vegetation phenology. The results revealed that (1) air temperature had significant increasing trends (P less then 0.05) in all sub-regions. Precipitation showed a non-significant increasing trend in Northwest China (NWC) and insignificant decreasing trends in North China (NC), Qinghai Tibet area (QTA), and South China (SC). (2) Integrated enhanced vegetation index (iEVI) and SPEI variations depicted that 2011 and 2016 were the extremely driest and wettest years during 2000-2017. (3) Rapid changes were observed in the vegetation phenology and productivity between 2011 and 2016. In 2011, changes in the vegetation phenology with the length of the growing season (ΔLGS) = was – 14 ± 36 days. Selleck Proteasome inhibitor In 2016, the overall net effect changed at the onset and end of the growing season with ΔLGS of 34 ± 71 days. The change in iEVI per SPEI increased rapidly with a changing rate of 0.16 from arid (NWC, and QTA) to semi-arid (NWC, QTA and NC) and declined with a rate of – 0.04 from semi-humid (QTA, NC, and SC) to humid (SC) region. A higher association was observed between iEVI and SPEI as compared to iEVI and precipitation. Our finding exposed that north China is more sensitive to climatic variation.