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Mushrooms: from nutrition to mycoremediation Full text
2017
Chatterjee, Soumya | Sarma, MukulK. | Deb, Utsab | Steinhauser, Georg | Walther, Clemens | Gupta, DharmendraK.
Mushrooms are well known as important food items. The uses of mushrooms in the cuisine are manifolds and are being utilized for thousands of years in both Oriental and Occidental cultures. Medicinal properties of mushrooms show an immense potential as drugs for the treatment of various diseases as they are rich in a great variety of phytochemicals. In this review, we attempted to encompass the recent knowledge and scientific advancement about mushrooms and their utilization as food or curative properties, along with their natural ability to accumulate (heavy) metals/radionuclides, which leads to an important aspect of bioremediation. However, accumulation of heavy metals and radionuclides from natural or anthropogenic sources also involves potential nutritional hazards upon consumption. These hazards have been pointed out in this review incorporating a selection of the most recently published literature.
Show more [+] Less [-]Sediment plume model—a comparison between use of measured turbidity data and satellite images for model calibration Full text
2017
Sadeghian, Amir | Hudson, Jeff | Wheater, Howard | Lindenschmidt, Karl-Erich
In this study, we built a two-dimensional sediment transport model of Lake Diefenbaker, Saskatchewan, Canada. It was calibrated by using measured turbidity data from stations along the reservoir and satellite images based on a flood event in 2013. In June 2013, there was heavy rainfall for two consecutive days on the frozen and snow-covered ground in the higher elevations of western Alberta, Canada. The runoff from the rainfall and the melted snow caused one of the largest recorded inflows to the headwaters of the South Saskatchewan River and Lake Diefenbaker downstream. An estimated discharge peak of over 5200 m³/s arrived at the reservoir inlet with a thick sediment front within a few days. The sediment plume moved quickly through the entire reservoir and remained visible from satellite images for over 2 weeks along most of the reservoir, leading to concerns regarding water quality. The aims of this study are to compare, quantitatively and qualitatively, the efficacy of using turbidity data and satellite images for sediment transport model calibration and to determine how accurately a sediment transport model can simulate sediment transport based on each of them. Both turbidity data and satellite images were very useful for calibrating the sediment transport model quantitatively and qualitatively. Model predictions and turbidity measurements show that the flood water and suspended sediments entered upstream fairly well mixed and moved downstream as overflow with a sharp gradient at the plume front. The model results suggest that the settling and resuspension rates of sediment are directly proportional to flow characteristics and that the use of constant coefficients leads to model underestimation or overestimation unless more data on sediment formation become available. Hence, this study reiterates the significance of the availability of data on sediment distribution and characteristics for building a robust and reliable sediment transport model.
Show more [+] Less [-]Source analysis of organic matter in swine wastewater after anaerobic digestion with EEM-PARAFAC Full text
2017
Zeng, Zhuo | Zheng, Ping | Ding, Aqiang | Zhang, Meng | Abbas, Ghulam | Li, Wei
Swine wastewater is one of the most serious pollution sources, and it has attracted a great public concern in China. Anaerobic digestion technology is extensively used in swine wastewater treatment. However, the anaerobic digestion effluents are difficult to meet the discharge standard. The results from batch experiments showed that plenty of refractory organic matter remained in the effluents after mesophilic anaerobic digestion for 30 days. The effluent total COD (tCOD) and soluble COD (sCOD) were 483 and 324 mg/L, respectively, with the sCOD/tCOD ratio of 0.671. Fluorescence excitation–emission matrix (EEM) coupled with parallel factor analysis (PARAFAC) revealed that the dissolved organic matter in the effluents was tryptophan-like substance, humic acid substance, and fulvic acid substance. Based on the appearance time during anaerobic digestion, tryptophan-like substance and humic acid substance were inferred to originate from the raw swine wastewater, and the fulvic acid substance was inferred to be formed in the anaerobic digestion. This work has revealed the source of residual organic matter in anaerobic digestion of swine wastewater and has provided some valuable information for the post-treatment.
Show more [+] Less [-]Effects of Se on the growth, tolerance, and antioxidative systems of three alfalfa cultivars Full text
2017
Dai, Huiping | Jia, Genliang
The aim of this study was to evaluate the selenium (Se) tolerance and exploit the physiological mechanisms in roots, stem, and leaves of three alfalfa cultivars to different concentrations of Se for 60 days. Among three cultivars, Medicago sativa ssp. displayed the highest Se concentrations in tissues, the largest Se amount in aerial parts, the highest bioconcentration factor (BCF) in aerial parts, and translocation factor (TF) under Se stress. Under Se stress, induced O₂•⁻ production in roots and leaves and increases in free proline and activities of antioxidative enzymes were observed in M. sativa ssp. Based on the above results, it is concluded that M. sativa ssp. is superior to the other two cultivars for Se phytoremediation, and its well-coordinated physiological changes under Se stress confer the great Se tolerance of this cultivar.
Show more [+] Less [-]Interaction of TiO2 nanoparticles with proteins from aquatic organisms: the case of gill mucus from blue mussel Full text
2017
Bourgeault, Adeline | Legros, Véronique | Gonnet, Florence | Daniel, Regis | Paquirissamy, Aurélie | Bénatar, Clémence | Spalla, Olivier | Chanéac, Corinne | Renault, Jean-Philippe | Pin, Serge
To better understand the mechanisms of TiO₂ nanoparticle (NP) uptake and toxicity in aquatic organisms, we investigated the interaction of NPs with the proteins found in gill mucus from blue mussels. Mucus is secreted by many aquatic organisms and is often their first line of defense against pathogens, xenobiotics, and other sources of environmental stress. Here, five TiO₂ NPs and one SiO₂ NP were incubated with gill mucus and run out on a one-dimensional polyacrylamide gel for a comparative qualitative analysis of the free proteins in the mucosal solution and the proteins bound to NPs. We then used nanoscale liquid chromatography coupled with tandem mass spectrometry to identify proteins of interest. Our data demonstrated dissimilar protein profiles between the crude mucosal solution and proteins adsorbed on NPs. In particular, extrapallial protein (EP), one of the most abundant mucus proteins, was absent from the adsorbed proteins. After thermal denaturation experiments, this absence was attributed to the EP content in aromatic amino acids that prevents protein unfolding and thus adsorption on the NP. Moreover, although the majority of the protein corona was qualitatively similar across the NPs tested here (SiO₂ and TiO₂), a few proteins in the corona showed a specific recruitment pattern according to the NP oxide (TiO₂ vs SiO₂) or crystal structure (anatase TiO₂ vs rutile TiO₂). Therefore, protein adsorption may vary with the type of NP. Graphical abstract Proteins with adsorption selectivity as identified from isolated bands
Show more [+] Less [-]Level, source identification, and risk analysis of heavy metal in surface sediments from river-lake ecosystems in the Poyang Lake, China Full text
2017
Zhang, Hua | Jiang, Yinghui | Ding, Mingjun | Xie, Zhenglei
The concentrations, sources, and risks of heavy metals (Fe, Al, Mn, Cr, Co, Ni, Cu, Zn, As, Cd, W, Pb, and Tl) in sediments in five river-lake ecosystems in the Poyang Lake region were studied. The concentrations of the heavy metals varied spatially, with most of the highest concentrations in the Raohe river-lake ecosystem (RH). All heavy metals except As, Cd, W, and Tl were enriched in sediments possessing high total organic carbon contents or in finer sediments. Based on enrichment factors and statistical methods, it was found that Cd in sediments in the Xiushui (XS), Ganjiang (GJ), Xinjiang (XJ) river-lake ecosystems, and RH; Mn in the XS, GJ, and RH; and W in the XS and GJ were greatly affected by anthropogenic inputs. Moreover, the origins of Cu, Zn, and As require more attention due to the high concentrations found. The high enrichment factor of Cd in the sediments indicated that this metal might cause significant pollution in the environment. The results of the modified potential ecological risk index revealed that the XS, GJ, RH, and XJ were at considerable ecological risk, while the sediments in the Fuhe river-lake ecosystem (FH) were at moderate ecological risk, with Cd contributing the highest proportion of risk. The hazard score fundamentally validated the modified potential ecological risk analysis and revealed a mean toxicity of 57.80% to the benthic organisms in the RH.
Show more [+] Less [-]Phenolic wastewaters depuration by electrochemical oxidation process using Ti/IrO2 anodes Full text
2017
Fajardo, Ana S. | Seca, Helga F. | Martins, Rui C. | Corceiro, Vanessa N. | Vieira, João P. | Quinta-Ferreira, M Emília | Quinta-Ferreira, Rosa M.
The electrochemical oxidation (EO) of phenolic wastewaters mimicking olive oil mill effluents was carried out in a batch stirring reactor using Ti/IrO₂ anodes, varying the nature (NaCl and Na₂SO₄) and electrolyte concentration (1.8–20 g L⁻¹), current density (57–119 mA cm⁻²) and initial pH (3.4–9). Phenolic content (TPh) and chemical oxygen demand (COD) removals were monitored as a function of applied charge and over time. The nature of the electrolyte greatly affected the efficiency of the system, followed by the influence of the current density. The NaCl concentration and the initial pH influenced the process in a lesser extent. The best operating conditions achieved were 10 g L⁻¹ of NaCl, current density of 119 mA cm⁻² and initial pH of 3.4. These parameters led to 100 and 84.8% of TPh and COD removal, respectively. Under these conditions, some morphological differences were observed by SEM on the surface of the anode after treatment. To study the potential toxicity of the synthetic effluent in neuronal activity, this mixture was applied to rat brain slices prior to and after EO. The results indicate that although the treated effluent causes a smaller depression of the neuronal reactive oxygen species (ROS) signal than the untreated one, it leads to a potentiation instead of recovery, upon washout. Furthermore, the purification of a real olive mill wastewater (OMW), with the organic load of the synthetic effluent, using the same optimised operating conditions, achieved total phenolic compounds abatement and 62.8% of COD removal.This study demonstrates the applicability of this EO as a pre-treatment process of a real effluent, in order to achieve the legal limit values to be discharged into natural streams regarding its organic load.
Show more [+] Less [-]Research trends and hotspots related to ammonia oxidation based on bibliometric analysis Full text
2017
Zheng, Maosheng | Fu, Hui-Zhen | Ho, Yuh-Shan
Ammonia oxidation is the rate-limiting and central step in global biogeochemistry cycle of nitrogen. A bibliometric analysis based on 4314 articles extracted from Science Citation Index Expanded database was carried out to provide insights into publication performances and research trends of ammonia oxidation in the period 1991–2014. These articles were originated from a wide range of 602 journals and 95 Web of Science Categories, among which Applied and Environmental Microbiology and Environmental Sciences took the leading position, respectively. Furthermore, co-citation analysis conducted with help of CiteSpace software clearly illustrated that ammonia-oxidizing bacteria (AOB), ammonia-oxidizing archaea (AOA), and anaerobic ammonia oxidation (anammox) were three dominant research themes. A total of 15 landmark works identified with the highest co-citation frequencies at every 8 years were extracted, which demonstrated that the establishments of culture-independent molecular biotechnologies as well as the discoveries of anammox and AOA played the most significant roles in promoting the evolution and development of ammonia oxidation research. Finally, word cluster analysis further suggested that microbial abundance and community of AOA and AOB was the most prominent hotspot, with soil and high-throughput sequencing as the most promising ecosystem and molecular biotechnology. In addition, application of anammox in nitrogen removal from wastewater has become another attractive research hotspot. This study provides a basis for better understanding the situations and prospective directions of the research field of ammonia oxidation.
Show more [+] Less [-]Comparing the photocatalytic activity of TiO2 at macro- and microscopic scales Full text
2017
Torras-Rosell, Antoni | Johannsen, Sabrina Rostgaard | Dirscherl, Kai | Daviðsdóttir, Svava | Jeppesen, Christian Sloth | Louring, Sascha | Andersen, Inge Hald
This study focuses on the characterization of photocatalytic TiO₂ coatings using Kelvin probe force microscopy. While most photocatalytic experiments are carried out at a macroscopic scale, Kelvin probe force microscopy is a microscopic technique that is surface sensitive. In order to link microscale results to macroscopic experiments, a simple method to establish the relation between Kelvin probe force microscopy and electrochemical measurements is presented by the calibration of a reference sample consisting of epitaxial deposited Cu-Ni-Au that is used as a transfer standard. The photocatalytic properties of TiO₂ at macro- and microscopic scales are investigated by comparing photocatalytic degradation of acetone and electrochemical experiments to Kelvin probe force microscopy. The good agreement between the macro- and microscopic experiments suggests that Kelvin probe force microscopy can be a valuable tool towards the understanding, standardization and design of TiO₂-based solutions in photocatalytic applications.
Show more [+] Less [-]Characteristic comparison of heavy metal contamination between road-deposited and roof-deposited sediments in suburban area Full text
2017
Yu, Jianghua | Yu, Haixia | Xu, Liqiang | Tao, Tao | Zhang, Yanxing | Hua, Yuhao | Nkolola, Namwiinga Babra
Surface-deposited sediment in urban area is an essential environmental medium for assessing heavy metal contamination. A total of 10 sampling trips were conducted to collect road-deposited and roof-deposited sediments for the comparison of nickel (Ni), copper (Cu), cadmium (Cd), lead (Pb), zinc (Zn), and chromium (Cr) contamination characteristics. Results indicated that roof sediment appeared to have a finer size distribution than road sediments. Roof sediment indicated higher metal concentration and lower surface loading than road sediment. The impact of particle size on heavy metal contamination was quantified by using the developed pioneering term of finer particle effect factor; it differed according to surface types and grain size fraction. Particles in individual grain size fraction showed different contribution to the surface loading for bulk sediments. No consistent trend was found for the grain size fraction loading along with grain size for the studied heavy metals for road sediments. In contrast, an asymmetric “W” trend was observed for the roof sediments, and it had the following results: Fraction of <63 and 250–500 μm showed higher loading, while fraction of 90–125 and >850 μm indicated the smaller loading. Findings above facilitated the appropriate management practice selection for the treatment of surface-deposited sediments.
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