ABSTR A C T Wastewater treatment plant (WWTP) effluents carrying plenty of nutrients and micropollutants pose serious threats to receiving rivers, however, the response of microbial community structure and function to WWTP ef-fluents discharge is still poorly understood. To address this knowledge gap, paired water and sediment samples from 17 sites of the Huangshui River, and effluents from 6 WWTPs were collected to investigate the effect of WWTP discharge on riverine microbial communities. Our results revealed that WWTP effluents exerted signif-icant effects on planktonic rather than sedimentary microorganisms in the receiving river. Notably, lower di-versity and richness of planktonic communities were observed in the effluent-influenced section (WRW) than other river sections (RW) along the urban river. Meanwhile, network analysis potentially revealed lower stability of co-occurrence patterns of microbial communities in WRW. The remarkably higher antibiotics, nitrate-nitrogen, and water temperature in WRW samples caused by WWTPs played essential roles in shaping the structure and function of planktonic microbial communities. This study suggested the enrichment of multiple-drug resistance genes and destruction of energy metabolisms were caused by sewage effluents, and high-lighted the importance of effective management strategies for protecting the ecological health of the receiving river.
The morphologically differentiated benthic macrofossils of algae and putative animal affinities of the Lantian biota in China represents the oldest known Ediacaran macroscopic eukaryotic assemblage. Although the biota provides remarkable insights into the early evolution of complex macroeukaryotes in the Ediacaran, the uncertainty in its age has hampered any robust biological evaluation. We resolve this issue by applying a petrographic-guided rhenium-osmium (Re-Os) organic-bearing sedimentary unit study on the Lantian biota. This work confines a minimum age for the first appearance of the Lantian biota to 602 +/- 7 Ma (2 sigma, including decay constant uncertainty). This new Re-Os date confirms that the Lantian biota is of early-mid Ediacaran age and temporally distinct from the typical Ediacaran macrobiotas. Our results indicate that the differentiation and radiation of macroscopic eukaryotes, and the evolution of the primitive, erect epibenthic ecosystem, occurred in the early-mid Ediacaran and were associated with highly fluctuating oceanic redox conditions. The radiogenic initial 187Os/188Os ratios derived from the Lantian (1.14 +/- 0.02) and other Ediacaran shales invoke oxidative weathering of upper continental crust in the early-middle Ediacaran, which may have stimulated the evolution of life and oceanic-atmospheric oxygenation. Integrated with published Ediacaran chronological and geochemical data, our new Re-Os geochemical study of the Lantian black shale provides a refined, time-calibrated record of environment and eukaryote evolution during the Ediacaran.
While household conversion to clean cooking fuels is well documented, the peer influence of neighbors on rural households using clean cooking fuels has not been investigated. This study examines the influence of neighbors on rural households switching to cleaner cooking fuels. Based on data from the 2018 China Family Panel Studies, this paper uses a spatial econometric model to analyze the neighborhood effects in the process of adopting clean cooking fuels among rural households in China. The findings show that neighborhood effects influence the adoption of clean cooking fuels by rural households in the same village through social norms and social multiplier effects. Neighborhood effects also indirectly promote the adoption of clean cooking fuels by rural households through the Internet. There is heterogeneity in the neighborhood effects on the adoption of clean cooking fuels by rural households. Therefore, this study recommends related policies to facilitate the transition to clean cooking fuel in rural regions.
Bacterial removal by sand filtration system is commonly inefficient due to the low bacterial adsorption capacity of sand. To improve the bacterial removal performance, biochar fabricated at different temperatures (400 °C, 550 °C and 700 °C) and arginine modified biochar were added into sand filtration columns as filter layers (0.5 and 1 wt%). Addition of biochar into sand columns could improve the removal efficiency for both Escherichia coli and Bacillus subtilis under both slow (4 m/day) and fast (240 m/day) filtration conditions. Bacterial removal efficiency in sand columns with the addition of biochar fabricated at 700 °C were higher than those fabricated at 400 °C and 550 °C due to its best bacterial adsorption capacity. Modification of biochar with arginine could further improve the bacterial removal performance. Specifically, complete bacterial removal (1.35 × 107 ± 10% cells/mL) could be achieved under both slow and fast filtration conditions in sand columns with 1 wt% arginine functionalized biochar amendment. The enhanced bacterial adsorption capacity mainly contributed to the increased bacterial capture performance in columns with addition of arginine-modified biochar. Bacteria more tightly bounded with arginine-modified biochar than bulk biochar. Moreover, complete bacterial removal with the copresence of 5 mg/L humic acid in suspensions was acquired in columns with addition of 1 wt% arginine-modified biochar. Efficient bacterial removal in actual river water, multiple filtration cycles as well as longtime injection duration (100 pore volumes injection) was also obtained. The results of this study demonstrated that arginine-modified biochar had great potential to treat water contaminated by pathogenic bacteria.
Understanding and manipulating geological pore structures is of paramount importance for geo-energy productions and underground energy storages in porous media. Nevertheless, research emphases for long time have been focused on understanding the pore configurations, while few work conducted to modify and restructure the porous media. This study deploys ultrasonic treatments on typical geological in-situ core samples, with follow-up processes of high-pressure mercury injections and nitrogen adsorptions and interpretations from nuclear magnetic resonance and x-ray diffraction. The core permeability and porosity are found to increase by 8.3 mD, from 4.1 to 12.4 mD, and by 0.95%, from 14.03% to 14.98%, respectively. Meanwhile, the number and size of the micro- and mesopore are increased with progressing of ultrasonic treatment, while those of the macropore decrease, which finally increase the permeability and porosity. The increase of micro- and mesopore number, from x-ray diffraction results, is attributed to the migration and precipitation of clay minerals caused through ultrasonic wave. The relocation of clay minerals also helps to improve the pore-throat connectivity and modify the micro-scale heterogeneity. Basically, this study reveals the characterizations of geological pore reconfigurations post-ultrasonic treatments and interprets the associated mechanisms, which provides guidance to manipulate the geological pores and be of benefit for further porous media use in science and engineering.
Despite the presence of hepatitis B virus (HBV) in the human breastmilk of mothers infected with HBV, it has been shown that breastfeeding does not increase the risk of mother-to-child transmission (MTCT) of HBV. We tested the hypothesis that human breastmilk may contain active components that bind to HBV and inhibit the infectivity of HBV. The results show that human whey significantly inhibited the binding of the hepatitis B surface antigen (HBsAg) to its antibodies in competitive inhibition immunoassays. The far-western blotting showed that HBsAg bound to a protein of 80 kD in human whey, which was identified as lactoferrin by mass spectrometry. Competitive inhibition immunoassays further demonstrated that both human lactoferrin and bovine lactoferrin bound to HBsAg. Human whey, human lactoferrin, and bovine lactoferrin each significantly inhibited the infectivity of HBV in vitro. Our results indicate that human breastmilk can bind to HBsAg and inhibit the infectivity of HBV, and the active component is lactoferrin. The findings may explain the reason that breastfeeding has no additional risk for MTCT of HBV, although human breastmilk contains HBV. Our study provides experimental evidence that HBV-infected mothers should be encouraged to breastfeed their infants.
Traditional core flooding experiments can only be used post breakthrough while what happens in the core prior to this time is vital to understand multiphase flow phenomenon for more successful EOR operations. We can overcome this obstacle through a visualized fluid displacement scheme. This can ultimately provide us with a reliable relative permeability curve that can lead to a more accurate reservoir simulation outcome in the field scale. In this study, NMR imaging is employed in a water flood experiment in conjunction with two separate numerical two-phase flow simulation methods (FDM and FEM), to reproduce experimental data. Using the Brooks-Corey equation, random pore size distribution indices (λ) are selected to generate relative permeability curves. Moreover, simulations are performed with FDM, and oil displacement efficiency, saturation maps, and saturation profiles are generated and compared to the experimental results. Next, FEM was employed in COMSOL for further validation and FDM results were found in agreement with the experiments. This way, an appropriate relative permeability curve was generated and assigned to the sample. Results suggest that λ of 0.2 generated the best numerical results with an MSE value of 0.009 in oil displacement efficiency curves, comparable to the experiments. Collectively, integration of imaging techniques with routine experimental fluid displacement procedures presented a detailed insight into complicated nature of multiphase flow phenomena in geomaterials.
Reports that the exploitation of metal-free carbon materials to enhance permanganate (PM) oxidation to abate organic pollution in water have emerged in recent publications. However, the activation mechanism and active sites involved are ambiguous because of the intricate physicochemical properties of carbon. In this study, reduced graphene oxide (rGO) as a typical carbon material exhibits excellent capability to boost permanganate oxidation for removing a wide array of organic contaminants. The simultaneous two reaction pathways in the rGO/PM system were justified: i) rGO donates to electrons to decompose PM and produce highly reactive intermediate Mn species for oxidizing organic contaminants; ii) rGO mediates electron transfer from organics to PM. Oxygen-containing groups (hydroxyl, carboxyl, and carbonyl) were justified as electron-donating groups, while structural defects (vacancy and edge defects) were shown to be critical for rGO-mediated electron transfer. Therefore, the oxidation pathway of the rGO/PM system can be controlled by regulating oxygen functional groups and structural defects. The changeover from electron donor to electron mediator by decorating surface active sites of carbon materials will be of great help to the design and application of carbocatalysts.
Effective control of nitrogen and phosphorus simultaneously is of great significance to satisfy the strict requirement of the ecological health of receiving waters. In this study, PHBV/ZVI composites made from solid carbon (poly-3-hydroxybutyrate-cohyroxyvelate, PHBV) and zero-valent iron (ZVI) were proposed to be functional fillers in biofilters for advanced wastewater treatment. Results showed that high-rate treatment performance was obtained with nitrate and phosphorus removal efficiencies of 79-97% and 97-98% in the biofilters packed with PHBV/ZVI composites. Lower N2O and CH4 emission (56.3-129.2 mu g m(-2) h(-1)) were also achieved simultaneously, further indicating the superiority of PHBV/ZVI composites applied in the wastewater treatment. High-throughput quantitative-PCR (HT-qPCR) results uncovered that the existence of ZVI could enrich carbon degradation genes (manA, gam and mxa) and facilitate denitrifier utilize organic matters more efficiently, as evidenced by up-regulations of genes involved in nitrate reduction (nirS and nosZ). Meanwhile, higher Fe concentration and less functional genes inducing lower activities of phosphate metabolism and in PHBV/ZVI systems indicated ZVI corrosion and coprecipitation were the main pathway of phosphorus removal. Network and redundancy analysis highlighted the role of ZVI in the removal of pollutants with keystone genes changed (pox and napA) and genes distribution remodeled compared to single PHBV fillers. Further, the activities of dehydrogenase (DHA) and nitrite reductase (Nir) enzymes also increased by the modulation of microbes, which explicitly interpreted the synergistic promotion of PHBV and ZVI on the denitrification process. These findings provided an alternative for the advanced treatment of wastewater and improve the understanding of C, N and P cycling in the co-occurrence of PHBV and ZVI.
Summary The documentation of biodiversity distribution through species range identification is crucial for macroecology, biogeography, conservation, and restoration. However, for plants, species range maps remain scarce and often inaccurate. We present a novel approach to map species ranges at a global scale, integrating polygon mapping and species distribution modelling (SDM). We develop a polygon mapping algorithm by considering distances and nestedness of occurrences. We further apply an SDM approach considering multiple modelling algorithms, complexity levels, and pseudo-absence selections to map the species at a high spatial resolution and intersect it with the generated polygons. We use this approach to construct range maps for all 1957 species of Fagales and Pinales with data compilated from multiple sources. We construct high-resolution global species richness maps of these important plant clades, and document diversity hotspots for both clades in southern and south-western China, Central America, and Borneo. We validate the approach with two representative genera, Quercus and Pinus, using previously published coarser range maps, and find good agreement. By efficiently producing high-resolution range maps, our mapping approach offers a new tool in the field of macroecology for studying global species distribution patterns and supporting ongoing conservation efforts.
Analog layout design is still primarily reliant on manual efforts. Current fully automated workflows are unable to meet the expectations for flexible customization and are incompatible with existing manual workflows. For both performance and productivity, interactive layout editing has the ability to bridge the gap between manual and automated flows. We present an interactive layout editing system in this study that includes well-defined commands for both placement and routing customization. This is a pioneering work that provides a holistic study on the interactive design methodology for analog layouts and its capability of speeding up design closure. Our framework comes up with instant placement legalization and routing adjustment mechanism for rapid layout update and modification. The framework is capable of handling realtime user interaction and improving the performance of fully automated layout generators verified by post-layout simulation on real-world analog designs. Experimental results demonstrate the performance enhancement on real-world analog designs with only a few editing commands. As examples, on the low-dropout regulator, our framework can reduce the overshot down and up voltage to nearly 1=3 of layout generated by automation tool with two editing commands, and on the operational transconductance amplifier, it achieves 33:5% better common mode rejection ratio with only one command.
