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To investigate the variations in environmental behavior (levels, distribution, sources, and soil toxicity) of polycyclic aromatic hydrocarbons (PAHs) under the impact of anthropogenic activities during the urbanization process, we collected soil samples from 195 sites in the Central Plains Urban Agglomeration (CPUA), North China, and analyzed 16 U.S. Environmental Protection Agency (EPA) PAH priority pollutants. We divided the sampling sites into three groups (urban area, industrial area, and farmland) and collected soil samples (0-20 cm surface layer). ∑

The occurrence of excessive ammonium in groundwater threatens human and aquatic ecosystem health across many places worldwide. As the fate of ammonium in groundwater systems is often affected by a complex mixture of transport and biogeochemical transformation processes, identifying the sources of groundwater ammonium is an important prerequisite for planning effective mitigation strategies. Elevated ammonium was found in both a shallow and an underlying deep groundwater system in an alluvial aquifer system beneath an agricultural area in the central Yangtze River Basin, China. In this study we develop and apply a novel, indirect approach, which couples the random forest classification (RFC) of machine learning method and fluorescence excitation-emission matrices with parallel factor analysis (EEM-PARAFAC), to distinguish multiple sources of ammonium in a multi-layer aquifer. EEM-PARAFAC was applied to provide insights into potential ammonium sources as well as the carbon and nitrogen cycling processes affecting ammonium fate. Specifically, RFC was used to unravel the different key factors controlling the high levels of ammonium prevailing in the shallow and deep aquifer sections, respectively. Our results reveal that high concentrations of ammonium in the shallow groundwater system primarily originate from anthropogenic sources, before being modulated by intensive microbially mediated nitrogen transformation processes such as nitrification, denitrification and dissimilatory nitrate reduction to ammonium (DNRA). By contrast, the linkage between high concentrations of ammonium and decomposition of soil organic matter, which ubiquitously contained nitrogen, suggested that mineralization of soil organic nitrogen compounds is the primary mechanism for the enrichment of ammonium in deeper groundwaters.

Iodine is an essential micronutrient in the human diet and an appropriate human iodine intake level is important for population health. Excessive iodine intake is often associated with high iodine groundwater which serves as an important drinking water source in many regions. This study aims to identify the source and key hydrogeochemical processes for iodine accumulation and mobility in the groundwaters of the Northern Jiangsu Yishusi Plain. Combined hydrogeochemical and statistical analyses, specifically random forest modeling and factor analysis, were used to explore the mechanisms affecting the spatial distribution of iodine. The concentration of iodine in the investigated groundwaters was found to vary widely and to range between 4.8 and 4750 μg/L, with 48.9% of the total samples (674) exceeding the threshold value of 100 μg/L for toxic exposure, as defined by the Chinese high‑iodine standard guideline. High iodine concentrations are shown to mainly occur in the marine plain and the shallow aquifer associated with the floodplains of the Old Yellow River. The marine or lagoons-facies sediments were identified as the most plausible iodine source. In addition, mixing of groundwater with paleo-seawater might also have played a role in the coastal area. In contrast, the flood sediments of the Old Yellow River are shown to be an unlikely source. However, they serve as a cover layer that favored the development of reducing hydrogeochemical conditions that can trigger iodine mobilization via the reductive dissolution of iron oxides and the degradation of organic matter. Slow groundwater flow rates also appear to favor iodine release from sediments.

Aim The aim of this study was to develop a novel long non-coding RNA (lncRNA) expression signature to accurately predict early recurrence for patients with hepatocellular carcinoma (HCC) after curative resection. Methods Using expression profiles downloaded from The Cancer Genome Atlas database, we identified multiple lncRNAs with differential expression between early recurrence (ER) and non-early recurrence (non-ER) groups of patients with HCC. Least absolute shrinkage and selection operator for logistic regression models were used to develop an lncRNA-based classifier for predicting ER in the training set. An independent test set was used to validate the predictive value of this classifier. Furthermore, a co-expression network based on these lncRNAs and its highly related genes was constructed and Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses of genes in the network were carried out. Results We identified 10 differentially expressed lncRNAs, including three that were upregulated and seven that were downregulated in the ER group. The lncRNA-based classifier was constructed based on seven lncRNAs (AL035661.1, PART1, AC011632.1, AC109588.1, AL365361.1, LINC00861, and LINC02084), and its accuracy was 0.83 in the training set, 0.87 in the test set, and 0.84 in the total set. Receiver operating characteristic curve analysis showed the area under the curve was 0.741 in the training set, 0.824 in the test set, and 0.765 in the total set. A functional enrichment analysis suggested that the genes highly related to four lncRNAs are involved in the immune system. Conclusion The expression profile of seven lncRNAs can effectively predict ER after surgical resection for HCC.

Although phenolic compounds linked to proteins or polysaccharides in the cell wall from herbal plant through β -glycoside bonds are difficult to extract in aqueous solution, microorganisms that produce some key enzymes may be useful for enhancing the release of phenolic compounds. Solid-state fermentation with a combination of different microorganisms was used to promote the bioactivities of the polyphenol component in GL. The results showed that co-fermentation of GL with Monascus anka GIM 3.592 and Saccharomyces cerevisiae GIM 2.139 led to a significant increase in contents of quercetin and total polyphenols. Including gallic acid, chlorogenic acid, rutin, isoquercitrin, avicularin, quercitrin, kaempferol, and quercetin, all polyphenols extracted from fermented guava leaves (FGL) were quantitatively identified by high-performance liquid chromatography time-of-flight electrospray ionization mass spectrometry (HPLC-TOF-ESI/MS). Quercetin, which presented the highest bioactivity, was significantly increased after microbial conversion. Total polyphenols extracted from FGL showed higher bioactivities in scavenging 1,1-Diphenyl-2-picrylhydrazyl (DPPH) and 2,2-Azino-bis 3-ethylbenzothiazoline-6-sulfonic acid diammonium salt (ABTS) caption radicals, anti-bacterial activity, and α-glucosidase inhibitory activity than those from GL. The activities of total polyphenols extracted from FGL by methanol were determined by calculating the IC 50 , with the highest values found to be 30.57 μg/mL, 24.53 μg/mL, and 0.09 mg/mL for the scavenging of DPPH and ABTS + radicals and inhibition of α-glucosidase, respectively. Methanol was more effective for extracting components with high α-glucosidase inhibitory activities than acetone. The methanol extract (0.20 mg/mL) efficiently inhibited 92.05% of α-glucosidase activity, which was significantly higher than that obtained using acarbose solution at an equal concentration. This microbial co-fermentation method can be used to upgrade the nutritional or medicinal values of herb leaves efficiently.

Understanding factors influencing groundwater quality is critical to the development of best management practices at the large watershed scale. In this study, the shallow groundwater (10&ndash, 20 m depth) in the Su-Xi-Chang region, eastern China, was investigated as part of a monitoring program from 2007 to 2008 to analyze the regional groundwater quality as well as the hydrogeochemical processes and their controlling factors. Conventional physicochemical water parameters (pH, turbidity, electrical conductivity, dissolved oxygen, total phosphorus), major cations (Na+, Ca2+, Mg2+ and NH4+) and anions (Cl&minus, NO3&minus, and SO42&minus, ) were measured. Hydrochemical methods and multivariate statistical methods were applied to analyze the hydrogeochemical signatures, origins, the similarities among the variables and to identify the main pollution sources in the groundwater. The results showed that (1) the concentrations of TDS (224.89&ndash, 1086.70 mg/L) and turbidity (0.1&ndash, 18.60 NTU) were higher than the class II groundwater quality standards in China and the WHO drinking water standards, (2) there were extremely high concentrations of ammonia (0.01&ndash, 32.90 mg/L), with a mean value of 0.72 mg/L and (3) the nitrate concentrations (average value of 22.07 mg/L) exceeded the class III groundwater quality standards. The study also provided evidence that weathering, dissolution of carbonate, halite and silicate and cation exchange were the possible primary hydrogeochemical control mechanisms in the groundwater. The sources of ammonia, total phosphorus, sulfates and nitrates included rock&ndash, water interactions and anthropogenic activities. The groundwater administration of pollution sinks and sources, long-term legal frameworks and economic incentives should be improved to optimize watershed scale management in the context of rapid development in China.

The g-C 3 N 4 /Bi 2 WO 6 composites have been synthesized and used as photocatalysts for degradation of methyl orange (MO) dye. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), infrared spectroscopy (IR), UV–visible diffuse reflection spectroscopy (DRS), and N 2 physisorption isotherms were used to characterize the physicochemical properties of the materials. With the increase of hydrothermal time, the morphology of Bi 2 WO 6 evolved from nanoparticles to microplates, flower-like and helix/tyre-like superstructures; in the meanwhile the g-C 3 N 4 component was gradually dissolved. Such obtained g-C 3 N 4 /Bi 2 WO 6 composites showed optical band gap in the range of 2.67–2.75 eV. Photocatalytic results showed that g-C 3 N 4 /Bi 2 WO 6 composites are more active than either pure Bi 2 WO 6 or g-C 3 N 4 , and the weight ratio of g-C 3 N 4 to Bi 2 WO 6 and the hydrothermal time significantly affected the degradation efficiency of the materials. The optimum weight ratio of g-C 3 N 4 to Bi 2 WO 6 was 0.5:1, and that for hydrothermal time was 6 h at 160 °C.

The upper reaches of the Heihe River have been regarded as a hotspot for phytoecology, climate change, water resources and hydrology studies. Due to the cold-arid climate, high elevation, remote location and poor traffic conditions, few studies focused on heavy metal contamination of soils have been conducted or reported in this region. In the present study, an investigation was performed to provide information regarding the concentration levels, sources, spatial distributions, and environmental risks of heavy metals in this area for the first time. Fifty-six surface soil samples collected from the study area were analyzed for Cr, Mn, Ni, Cu, Zn, As, Cd and Pb concentrations, as well as TOC levels. Basic statistics, concentration comparisons, correlation coefficient analysis and multivariate analyses coupled with spatial distributions were utilized to delineate the features and the sources of different heavy metals. Risk assessments, including geoaccumulation index, enrichment factor and potential ecological risk index, were also performed. The results indicate that the concentrations of heavy metals have been increasing since the 1990 s. The mean values of each metal are all above the average background values in the Qinghai Province, Tibet, China and the world, except for that of Cr. Of special note is the concentration of Cd, which is extremely elevated compared with all background values. The distinguished ore-forming conditions and well-preserved, widely distributed limestones likely contribute to the high Cd concentration. Heavy metals in surface soils in the study area are primarily inherited from parent materials. Nonetheless, anthropogenic activities may have accelerated the process of weathering. Cd presents a high background concentration level and poses a severe environmental risk throughout the whole region. Soils in Yinda, Reshui daban, Kekeli and Zamasheng in particular pose threats to the health of the local population, as well as that of livestock and wildlife.

Understanding the heavy metal (HM) contamination in alpine mountain headwaters regions is important to maintaining the ecosystem stability of the basin. A total of 119 water samples and 104 sediment samples were collected along tributaries and the main course of Heihe River. The concentrations of eight heavy metals (As, Cd, Cr, Cu, Mn, Ni, Pb, and Zn) in water and sediment were measured to describe their spatial variability and to assess water quality. To identify the origins and pathways of HMs, anions, cations, and trace elements, as well as &delta, D/&delta, 18O stable isotopes in water samples were also measured. The results of water quality assessment suggested that tributaries were affected by local mining activity. Factor analysis in sediments showed that all HMs in sediments were inherited from the parent bedrock. Both natural weathering and mining contribute HMs. Cr and Ni were homologous with a source from the weathering of basic gabbro and serpentine at Yushigou. Mn appeared to be influenced more by artificial activities such as agriculture and grazing. Depending on the mining technique involved, two pathways for the release of HMs were distinguished in this area. For open-pit mining, mining promoted the release of HMs primarily via enhanced weathering. For underground mining, HMs might have contributed to greater acid mine discharge at high elevations due to the weak weathering processes. As the elevation decreases, precipitation increases, and a series of complex hydrological factor significantly affect leaching and runoff. The study results can be applied to improve water management efficiency.

MHD phenomena in a duct flow were studied experimentally by using copper electrodes inserted into the wall of a perfectly insulated duct. The electrodes were connected using a copper wire to imitate different insulator coating imperfection conditions. The experimental results show instabilities of electric potential at the wall (surface instabilities) as well as instabilities in the pressure and velocity (bulk instabilities). The instabilities are strongly dependent on the scale of the copper wire. Three different cases were studied (at the same flow regimes, but with different electrode connections), where the potential at the duct wall is smaller, equal to or higher than the product of duct diameter 2a0 and transverse magnetic field B0 and average velocity V0. MHD pressure drop ΔP also exhibits significant changes.