خيارات البحث
النتائج 3941 - 3950 من 5,153
Assessment of Lemna minor (duckweed) and Corbicula fluminea (freshwater clam) as potential indicators of contaminated aquatic ecosystems: responses to presence of psychoactive drug mixtures النص الكامل
2018
Bourioug, Mohamed | Mazzitelli, Jean-Yves | Marty, Pierre | Budzinski, Hélène | Aleya, Lotfi | Bonnafé, Elsa | Geret, Florence
The pharmaceutical products are emerging pollutants continuously released into the environment, because they cannot be effectively removed by the wastewater treatment plants. In recent years, questions have been raised concerning the environmental risks related to these pollutants. The goal of this research was to evaluate the responses in Lemna minor after 7 days and in Corbicula fluminea after differing durations (1, 3, 7, and 19 days) of exposure to the psychoactive drug mixture (valproic acid, citalopram, carbamazepine, cyamemazine, hydroxyzine, oxazepam, norfluoxetine, lorazepam, fluoxetine, and sertraline) in different concentrations (0, 0 + ethanol, drug concentration (DC) 1 = river water concentration, DC2 = effluent concentration, and DC3 = 10× effluent concentration). In this aim, growth parameters of L. minor, gluthathione S-transferase (GSTs), catalase (CAT), ethoxyresorufin-O-deethylase (EROD) and/or gene expressions (pi-gst, cat, cytochrome P450 4 (cyp4), multidrug resistant 1 (mdr1), and superoxide dismutase (sod)) were measured. GST activities increased significantly in L. minor exposed to DC3, but no changes were found in CAT activity. In C. fluminea, EROD activity was induced significantly in both gill and digestive gland tissues after 3 days’ exposure to DC3, while a GST increase was observed only in digestive gland tissues, suggesting that these pharmaceuticals induced an oxidative effect. Gene expression analysis revealed transient transcriptomic responses of cyp4, sod, and mdr1 under drug concentrations 2 or 3 and no change of expression for the other genes (cat and pi-gst) or condition (environmental drug concentration) tested. Finally, the data reported in this study represent important ecotoxicological information, confirming that this enzyme family (cyp4, sod, and mdr1) may be considered as a sensible and early indicator of exposure to drugs and emphasizing the involvement of selected genes in detoxification pathways.
اظهر المزيد [+] اقل [-]Soil physical properties response to tillage practices during summer fallow of dryland winter wheat field on the Loess Plateau النص الكامل
2018
Xue, Jian-Fu | Ren, Ai-Xia | Li, Hui | Gao, Zhi-Qiang | Du, Tian-Qing
Soil physical properties are a greatly important part of the soil and indicator of soil quality, which can directly affect soil nutrient turnover and crop yields in dryland. This study was carried out with three tillage practices during the summer fallow season since 2011, including no tillage (NT), plow tillage (PT), and subsoiling (ST) in dryland winter wheat fields of the Loess Plateau. Results showed that soil tillage during the summer fallow had a small effect on soil bulk density (ρ b) in the 0–50-cm soil profile before sowing and after harvesting of winter wheat. Soil ρ b under NT at a depth of 20–30 cm was significantly greater than those under PT in both seasons. Both soil gravimetric water content (θ g) and volumetric moisture content (θ ᵥ) after harvesting increased by 28.8–78.6% and 37.5–87.3%, respectively, compared with those before sowing. Adoption of PT significantly increased soil θ g and θ ᵥ in the entire 0–50-cm profile before sowing compared with NT and ST (P < 0.05). In addition, there was a small effect on soil porosity (e.g., total porosity, air-filled porosity, and capillary porosity) in the profile of 0–50 cm both before sowing and after harvesting. Overall, short-term tillage during summer fallow mainly affected soil water content in the 0–50-cm soil profile, and it had a slight effect on other physical soil properties.
اظهر المزيد [+] اقل [-]The hierarchical porous structure bio-char assessments produced by co-pyrolysis of municipal sewage sludge and hazelnut shell and Cu(II) adsorption kinetics النص الكامل
2018
Zhao, Bing | Xu, Xinyang | Zeng, Fanqiang | Li, Haibo | Chen, Xi
The co-pyrolysis technology was applied to municipal sewage sludge (MSS) and hazelnut shell with alkaline activating agent K₂CO₃ under N₂ atmosphere. The innovative bio-char produced by co-pyrolysis had significant physical and chemical characteristics. The specific surface area reached 1990.23 m²/g, and the iodine absorption number was 1068.22 mg/g after co-pyrolysis at 850 °C. Although hazelnut shell was a kind of solid waste, it also had abundant cellulose resource, which could contribute to porous structure of bio-char during co-pyrolysis with MSS and decrease total heavy metals contents of raw material to increase security of bio-chars. Meanwhile, the residual fractions of heavy metals in bio-char were above 92.95% after co-pyrolysis at 900 °C except Cd to prevent heavy metals digestion, and the bio-char presented significant immobilization behavior from co-pyrolysis technology. Moreover, the yield and the iodine absorption number of bio-chars under different process variables were analyzed, and it was confirmed that appropriate process variables could contribute the yield and the iodine absorption number of bio-char and prevent to etch pore structure excessively to collapse. The changes of surface functional groups and crystallographic structure before and after co-pyrolysis were analyzed by FTIR and XRD, respectively. The hierarchical porous structure of bio-char was presented by SEM and N₂ adsorption-desorption isotherm. The Cu(II) adsorption capacity of the bio-char was 42.28 mg/g after 24 h, and surface functional groups acted as active binding sites for Cu(II) adsorption. Langmuir model and pseudo-second-order model can describe process of Cu(II) adsorption well.
اظهر المزيد [+] اقل [-]User preferences and water use savings owing to washbasin taps retrofit: a case study of the DECivil building of the University of Aveiro النص الكامل
2018
Meireles, Inês | Sousa, Vítor | Adeyeye, Kemi | Silva-Afonso, Armando
During the last decades, achieving water efficiency in buildings has increasingly become an important challenge in the scope of sustainability. Water consumption is directly related to individual conduct. Despite the various technological improvements in fixtures and appliances, their performance will be influenced by human preferences and behavior. As a result, the potential for effective water consumption saving is influenced by behavior change as well as water-efficient fixtures and appliances. This work evaluates the impact of user preferences and behavior change on the water-efficient performance of tap aerators in a case study building: the Department of Civil Engineering building of the University of Aveiro, Portugal. Four aerators with different discharge reductions and types were installed in the toilet’s washbasins and the user’s preferences and behavior change measured through direct and online questionnaires. It was observed that the effective water consumption reduction (15 to 49%) was less than the discharge reduction (30 to 70%), confirming that user factors influence water savings. Water use reductions in the tested range (2.0 to 6.7 l/min) also varied according to gender, with male users using less water than their female counterparts. It was noted that an awareness of sustainability values prevailed amongst the users when confronted with the choice between comfort and water efficiency, although differences were observed in the user preferences regarding the various aerators. When confronted with the information that the lower discharge aerator would contribute to a reduction of about 70% on the water discharge, 25% of the users agreed with its use, even if it resulted in a certain degree of dissatisfaction. In comparison, only 8% of the users completely disagreed with its installation. On average, the water consumption reduction was 46% smaller than the discharge reduction achievable with the aerator alone. This further confirms the user factors inform the degree of water savings that is achievable from water-efficient fittings and fixtures.
اظهر المزيد [+] اقل [-]Phytoextraction with Salix viminalis in a moderately to strongly contaminated area النص الكامل
2018
Tőzsér, Dávid | Harangi, Sándor | Baranyai, Edina | Lakatos, Gyula | Fülöp, Zoltán | Tóthmérész, Béla | Simon, Edina
We tested the suitability of Salix viminalis for phytoextraction with the analysis of selected elements in soil, root, and leaf, and by visual tree condition assessment in an area with varying levels of contamination. Bioconcentration factor (BCF) and translocation factor (TF) were used to assess the phytoextraction potential of willows. The middle part of the study area was strongly contaminated, while the northern and southern parts were moderately contaminated. We found increasing element concentrations toward deeper layers. Mean concentrations of elements in roots were similar among the three parts, while in leaves the highest concentrations were found in the strongly contaminated part of the study area. Tree condition scores were the lowest in the strongly contaminated part of the study area, which was caused by Al, Ca, K, Mg, Ni, Sr, and Zn concentration. These elements induced leaf disease and leaf feeders. The highest BCF values were found for Cu, Fe, Mn, and Zn in root, and for Cd and Zn in leaves, indicating that S. viminalis had high accumulation potential of these elements. Furthermore, TF values were high for Cd, Mn, Sr, and Zn. Our results also demonstrated that soil element composition has major influence on the condition of S. viminalis individuals. Furthermore, visual condition assessment was found to be a useful tool to assess the phytoextraction potential of trees.
اظهر المزيد [+] اقل [-]Community response to a sustainable restoration plan for a superfund site النص الكامل
2018
Sidhu, Virinder | Sarkar, Dibyendu | Datta, Rupali | Solomon, Barry
Large-scale copper (Cu) mining activities in Michigan’s Upper Peninsula produced millions of metric tons of mining wastes also known as stamp sands. The stamp sands containing high concentrations of Cu were disposed of into several lakes connected to the Lake Superior. Eventually, as aquatic organisms in these lakes started to exhibit toxicity symptoms, the stamp sands were dredged and discarded on the lake shores. Consequently, these areas turned into degraded, marginal lands and were collectively classified as a Torch Lake Superfund site by the US EPA. Due to the lack of vegetative cover, the Cu-rich stamp sands eroded into the lakes, affecting the aquatic life. To alleviate this issue, a sustainable restoration plan (SRP) was developed and tested in a greenhouse environment prior to field implementation. Cold-tolerant oilseed crops, camelina (Camelina sativa) and field pennycress (Thlaspi arvense), were grown on compost-fertilized stamp sands, which reduced soil erosion by acting as a vegetative cap. Oilseed plants produced normal yield, demonstrating their potential utilization as biofuel feedstock. Prior to implementing the SRP in field-scale in the Torch Lake Superfund site, a public opinion survey of the local community was conducted to understand the views of residents. Door-to-door survey was performed in July–August 2015, which yielded a response rate of 68.1%. Results showed that residents were generally concerned with stamp sand erosion into the Torch Lake and were overwhelmingly supportive of the SRP, which would not only provide environmental benefits but could boost the local economy via biofuel production. To gauge the general environmental awareness of the respondents, the survey included questions on climate change. Most of the respondents acknowledged that climate change is real and anthropogenically mediated. Having college education and a relatively high annual household income showed a positive and significant correlation with climate change awareness.
اظهر المزيد [+] اقل [-]Microwave-assisted extraction and dyeing of chemical and bio-mordanted cotton fabric using harmal seeds as a source of natural dye النص الكامل
2018
Adeel, Shahid | Zuber, Muhammad | Fazal-ur-Rehman, | Zia, KhalidMahmood
The revival of cultural heritage in a form of natural colorants for textile dyeing is gaining popularity due to their soothing nature and bright shades. The present study was conducted to explore the coloring potential of harmala (Peganum harmala) seeds and to improve color strength of dye using microwave radiations followed by a mordanting process. The results showed that harmala plant seeds could be an excellent source of natural dyes for cotton dyeing if the irradiated acidified methanolic extract (RE, 4 min) is used to dye un-irradiated fabric (NRC) at 85 °C for 45 min using a dye bath of pH 9.0 having salt concentration of 7 g/100 mL. Alum (1%) as pre-mordants and iron (7%) as post-mordants have improved the color strength in chemical mordanting more than other mordants employed. The bio-mordants employed reveal that 10% of acacia as pre-bio-mordants and 7% of acacia as post-bio-mordants are effective amounts to obtain high color strength. Suggested ISO standards for colorfastness illustrate that bio-mordanting has given more excellent rating as compared to chemical mordants. It is concluded that harmala seeds have a great potential to act as a source of natural colorant for cotton dyeing under the influence of microwave radiation.
اظهر المزيد [+] اقل [-]Better kitchens and toilets: both needed for better health النص الكامل
2018
Ravindra, Khaiwal | Smith, KirkR.
Both poor water, sanitation, hygiene (WaSH) and household air pollution (HAP) adversely affect the health of millions of people each year around the globe and specifically in developing countries. The objective of current work is to highlight the importance of HAP in parallel to WaSH for decision making to achieve better health specially in developing countries. There are examples, where developing countries are strengthening efforts to tackle the issue of poor water and sanitation such as ‘Clean India Mission’ was recently launched by the Government of India. However, there is lack of actions to address the issue related to HAP—to extend the coverage of clean fuel, efficient stoves and ventilated kitchens to the deprived population under the ‘Clean India Mission’. Most of the rural household and urban slums in developing countries have only a single room, where people cook and sleep. This leads them to exposure to toxic HAP, which can be minimized by developing country specific indoor air quality guidelines and action framework. Hence, there should be policies to provide them not only the subsidy for clean fuel but also to build properly ventilated kitchens along with the promotion of clean toilets and water supplies. There is a need to strengthen global efforts, to jointly address the challenges associated with the risks related to WaSH and HAP in order to efficiently reduce the global burden of disease. Further, this will also help to timely attain the sustainable development goals for better health and environment.
اظهر المزيد [+] اقل [-]Biogenic synthesis of silver nanoparticles using Piper betle aqueous extract and evaluation of its anti-quorum sensing and antibiofilm potential against uropathogens with cytotoxic effects: an in vitro and in vivo approach النص الكامل
2018
Srinivasan, Ramanathan | Vigneshwari, Loganathan | Rajavel, Tamilselvam | Durgadevi, Ravindran | Kannappan, Arunachalam | Balamurugan, K. (Krishnaswamy) | Pandima Devi, Kasi | Veera Ravi, Arumugam
Urinary tract infections are the utmost common bacterial infections caused by Proteus mirabilis, Pseudomonas aeruginosa, Escherichia coli, and Serratia marcescens. These uropathogens resist the action of several antibiotics due to their ability to form biofilms. Most of these bacterial pathogens use the quorum sensing (QS) machinery to co-ordinate their cells and regulate several virulence factors and biofilm formation. On the other hand, the anti-quorum sensing (anti-QS) and antibiofilm potential of silver nanoparticles have been well reported against certain bacterial pathogens, but to the best of our knowledge, no report is available against the pathogenicity of uropathogens in particular S. marcescens and P. mirabilis. Therefore, the present study is primarily focused on the anti-QS and antibiofilm potential of Piper betle-based synthesized silver nanoparticles (PbAgNPs) against S. marcescens and P. mirabilis. Initially, the silver nanoparticles were synthesized by the aqueous extract of P. betle and characterized by UV-absorbance spectroscopy, XRD, FT-IR, SEM, TEM, and DLS. The synthesized silver nanoparticles were assessed for their anti-QS activity and the obtained results revealed that the PbAgNPs inhibited the QS-mediated virulence factors such as prodigiosin, protease, biofilm formation, exopolysaccharides and hydrophobicity productions in uropathogens. The gene expression analysis divulged the downregulation of fimA, fimC, flhD, and bsmB genes in S. marcescens and flhB, flhD, and rsbA genes in P. mirabilis, respectively. The in vivo Caenorhabditis elegans assays revealed the non-toxic and anti-adherence efficiency of PbAgNPs. Furthermore, the non-toxic effect of PbAgNPs was also confirmed through peripheral blood mononuclear cells and normal lung epithelial cells. Therefore, the contemporary study demonstrates the use of PbAgNPs as a possible alternative toward conventional antibiotics in controlling QS and biofilm-related uropathogen infections.
اظهر المزيد [+] اقل [-]High efficacy of (Z)-γ-bisabolene from the essential oil of Galinsoga parviflora (Asteraceae) as larvicide and oviposition deterrent against six mosquito vectors النص الكامل
2018
Govindarajan, Marimuthu | Vaseeharan, Baskaralingam | Alharbi, NaiyfS. | Kadaikunnan, Shine | Khaled, JamalM. | Al-anbr, MohammedN. | Alyahya, SamiA. | Maggi, Filippo | Benelli, Giovanni
The eco-friendly management of mosquitoes with novel and effective larvicides and oviposition deterrents is a crucial challenge to prevent outbreaks of mosquito-borne diseases. However, most of the herbal formulations tested in these years showed LC₅₀ values higher of 40 ppm, and significant oviposition deterrent activity only when tested at relatively higher doses (> 50 μg/ml). Herein, we studied the chemical composition of the Galinsoga parviflora essential oil (EO). This plant is an annual herb native to South America naturalized all over the world. We tested the EO larvicidal and oviposition deterrent action on 6 mosquito species. Totally 37 compounds were identified in the EO of G. parviflora by GC and GC-MS analyses. The major constituent was (Z)-γ-bisabolene (38.9%). The G. parviflora EO and (Z)-γ-bisabolene showed acute toxicity on An. stephensi (LC₅₀ = 31.04 and 2.04 μg/ml, respectively), Ae. aegypti (LC₅₀ = 34.22 and 2.26 μg/ml, respectively), Cx. quinquefasciatus (LC₅₀ = 37.10 and 2.47 μg/ml, respectively), An. subpictus (LC₅₀ = 40.97 and 4.09 μg/ml, respectively), Ae. albopictus (LC₅₀ = 45.55 and 4.50 μg/ml, respectively) and Cx. tritaeniorhynchus (LC₅₀ = 49.56 and 4.87 μg/ml, respectively) larvae. Furthermore, the oviposition deterrent potential of the G. parviflora EO and (Z)-γ-bisabolene was studied on six mosquito vectors, showing that 25 μg/ml of (Z)-γ-bisabolene led to an Oviposition Activity Index lower of − 0.79 in all tested mosquito vectors. Overall, all larvicidal LC₅₀ values estimated for (Z)-γ-bisabolene were lower than 5 μg/ml. This result far encompasses current evidences of toxicity reported for the large majority of botanical products currently tested against mosquito young instars, allowing us to propose this compound as an highly effective mosquito larvicide and oviposition deterrent.
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