خيارات البحث
النتائج 4611 - 4620 من 6,535
Toxicological potential of penconazole on early embryogenesis of white mice Mus musculus in either pre- or post-implantation exposure النص الكامل
2020
El-Shershaby, Abd El-Fattah M. | Lashein, Fakhr El-Din M. | Seleem, Amin A. | Ahmed, Abeer A.
The present investigation was conducted to evaluate the effect of penconazole (PEN) fungicide on early embryogenesis of white mice. In the first experiment, 48 pregnant females were divided into different groups; the first group is control (G1). The second group (G2) was treated daily with PEN (30-, 20-, 10-, 5-mg/kg BW). The third group (G3) was treated with PEN (5-mg/kg BW; day after the other day). The fourth group (G4) was treated with PEN (2.5-mg/kg BW daily) during pre-implantation stage (from the 1st to the 4th day of gestation). The fifth group (G5) was treated with PEN (2.5-mg/kg BW daily) during post-implantation (from the 5th to the 8th day of gestation). The pregnant females were sacrificed at the 14th day of gestation. In the second experiment, 63 pregnant females were classified into control, PEN-treated during pre-implantation period (2.5-mg/kg BW), and PEN-administered during post-implantation period (2.5-mg/kg BW). Each group was sacrificed at stages E6.5, E7.5, E8.5, E9.5, E11.5, E14.5, and E18.5. The high doses of PEN in the first experiment showed failed pregnancy, foetoresorption, and embryo disorganization. High doses of PEN induce alterations in the uterus tissue at the level of histology and immunohistochemistry for the expression of TGFβ2, TNFR2, Caspase 10, and HSP70. The low doses of PEN in the second experiment showed upregulated expression of TGFβ2, TNFR2, Caspase 10, and HSP70 at stages E6.5 and E7.5. In conclusion, PEN was found to alter the suitable uterine environment for proper implantation and development at the levels of histological and immunohistochemical that could create a risk during the full course of embryogenesis.
اظهر المزيد [+] اقل [-]Implementation and evaluation of WRF simulation over a city with complex terrain using Alos-Palsar 0.4 s topography النص الكامل
2020
Guevara Luna, Marco Andrés | Casallas, Alejandro | Belalcázar Cerón, Luis Carlos | Clappier, Alain
Air quality modeling requires an accurate representation of meteorology, and in cities with complex topography, the performance of meteorological modeling can be improved by using an alternative global digital elevation model (GDEM) such as Alos-Palsar 0.4 s instead of the default elevation data. Bogotá is a city with complex topography geographically located over the Andes Mountains at 2600 m.a.s.l. A reliable meteorological simulation model is critical for performing a suitable air quality modeling in any case of study. Previous researches have been developed using the standard Weather Research and Forecast (WRF) topography (GTOPO 30 s). These studies have been developed with different configurations for the representation of meteorology. The aim of this study is to evaluate Alos-Palsar 0.4 s topography with WRF, and two domain configurations with horizontal spatial resolutions up to 1000 m, to establish a reliable and accurate way to simulate the meteorology in the city of Bogotá. The evaluation quantitative parameters: IOA, r (Pearson), RMSE, MGE, and MB were calculated for the quantitative evaluation of temperature, relative humidity, wind speed, wind direction, and solar radiation. An additional evaluation using Taylor diagrams was performed. Spatial differences were identified in the same locations as well the differences between the elevation from Alos-Palsar 0.4 s and GTOPO30. The results and evaluation suggest that simulations based on Alos-Palsar 0.4 s topography lead to a significant improvement in the meteorology representation by WRF in a region with complex topography such as Bogotá, Colombia.
اظهر المزيد [+] اقل [-]Marine macroalgae as food for earthworms: growth and selection experiments across ecotypes النص الكامل
2020
Butt, Kevin Richard | Méline, Camille | Pérès, Guénola
Historically, subsistence farmers around the Atlantic coast of NW Europe utilized marine algae as a fertilizer in agroecosystems, a practice that continued in small areas and is now considered to have real potential for re-establishing sustainable food production systems on marginal soils. Earthworms form a significant component of soil fauna, and their ecosystem services are well-documented. Therefore, palatability of marine organic amendments to faunal detritivores of terrestrial systems is of interest. This work aimed to assess the potential for growth of Aporrectodea caliginosa, Lumbricus rubellus and Aporrectodea longa fed with two common macroalgae (seaweeds), Laminaria digitata and Fucus serratus. In addition, choice chambers were constructed to permit earthworm selection of these macroalgae with more conventional organic materials, horse manure (HM) and birch leaves (BL). Over a period of 2 months, earthworm species showed significantly greater mass gain with conventional food (p < 0.05). Laminaria outperformed Fucus, which in turn was superior to soil alone. Similarly, when given a choice, a significant preference (p < 0.001) was shown for the more nitrogen-rich HM and BL over the seaweeds. No removal was recorded for A. caliginosa when offered seaweeds only. By contrast, L. rubellus and A. longa showed significant preferences (p < 0.001) for Laminaria over Fucus and fresh material over degraded. These results underline an interest to profit from natural resources (seaweeds) to maintain or improve soil biological quality in marginal coastal areas.
اظهر المزيد [+] اقل [-]Stakeholders’ perspective on strategies to promote contaminated site remediation and brownfield redevelopment in developing countries: empirical evidence from Pakistan النص الكامل
2020
Ahmad, Naveed | Zhu, Yuming | Shao, Jing | Lin, Hongli
Due to the potential of reducing negative outcomes of brownfields on environment and contribution to urban sustainability, brownfield redevelopment (BR) gained considerable recognition in the more recent era. Comprehensive literature shows that many studies proposed strategies to promote BR in developed nations; however, studies focusing on developing economies are scarce. Therefore, this study intends to identify significant strategies to promote BR in developing countries by taking the case of Pakistan. A comprehensive literature review and expert opinion were commenced to identify potential strategies. Data were collected from the main stakeholders involved in BR process through an empirical questionnaire. The findings revealed that “Low-interest loans and subsidies with the collaboration of government and financial institutions,” “Standardized definition, guidelines, and simplified brownfield process,” “Development of technical and infrastructure support,” “Create investors interest,” “Strengthening remediation technologies R&D” were the five most important strategies to promote BR in Pakistan. Theoretically, the novelty of the current study is to highlight the key strategies to promote BR in developing countries. Practically, the study facilitates governments, urban policymakers, environmentalists, and stakeholders to propose and implement appropriate strategies for promoting BR. Future studies can consider modeling the interactions between strategies and their impact on BR adoption.
اظهر المزيد [+] اقل [-]Effective allocation of resources in water pollution treatment alternatives: a multi-stage gray group decision-making method based on hesitant fuzzy linguistic term sets النص الكامل
2020
Wang, Jue | Qian, Wuyong | Du, Junliang | Liu, Yong
With the significant economic shift, water pollution treatment has gradually become a key problem which needs to be deeply investigated for the sustainable development of China. In the face of specific water pollution incidents, multiple alternatives are often required to work together in order to achieve better results. However, due to the limitation of resources, alternatives must be ranked to realize the effective allocation of resources, which means the more highly ranked ones should possess more disposable resources. Furthermore, the water pollution treatment process is a multi-stage and multi-objective process. In each stage, decision-makers may have different emphasis and thus have different preferences for the treatment alternatives. How to effectively aggregate decision-makers’ preferences in different stages into an overall preference so as to form a ranking of treatment alternatives under global constraints has turned into a problem worthy of discussion. Under such background, this paper proposes a multi-stage gray group decision-making method, where decision-makers use Group-G1 to rank and weight the criteria, and in this way, the weights of decision-makers and criteria in each stage could be determined. Considering the difference and deficiency of the cognitive level of decision-makers, this paper adopts the form of hesitant fuzzy linguistic term sets (HFITS) to express the evaluation information of decision-makers. And then, gray incidence analysis is selected to rank the alternatives. After ranking the alternatives in each stage, the multi-stage rankings will be aggregated into an overall ranking and the resource allocation is made according to the priorities of the alternatives. Finally, an example of water pollution treatment alternatives ranking based on a cyanobacterial bloom in Taihu Lake, China, is given to illustrate the proposed approach.
اظهر المزيد [+] اقل [-]Trace elements, polycyclic aromatic hydrocarbons, mineral composition, and FT-IR characterization of unrefined sea and rock salts: environmental interactions النص الكامل
2020
Karavoltsos, Sotirios | Sakellari, Aikaterini | Bakeas, Evangelos | Bekiaris, Georgios | Plavšić, Marta | Proestos, Charalampos | Zinelis, Spiros | Koukoulakis, Konstantinos | Diakos, Ioannis | Dassenakis, Manos | Kalogeropoulos, Nick
Unrefined sea salt originates from seawater, typically by natural evaporation. Being minimally processed, it contains the natural minerals and impurities of seawater. Despite the wide applications of salt for culinary and food preservation purposes, the available composition data is particularly limited. Since seawater often contains various harmful substances at a trace or ultra-trace level, their determination in unrefined salt is significant in terms of quality control and food safety. Twenty-four (24) samples of unrefined sea and rock salts retailed in Greece were studied in terms of their trace metals and polycyclic aromatic hydrocarbon (PAH) content, which constitute the usual pollutants examined in seawater. In addition, samples’ color and mineralogy were recorded and their attenuated total reflectance Fourier transform infrared (ATR FT-IR) spectra were obtained. No statistically significant differences were found between sea and rock salts regarding their trace metal (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn) content (excluding V) and the 15 PAHs examined. ATR FT-IR succeeded to discriminate among sea, rock, flower, and underground salty water salts. Compared with the typical trace metal concentrations in seawater, quite high Pb values were determined in both sea and rock salts, whereas outliers in the rest of the trace elements examined were scarce. Median values of the sum of PAH (ΣPAHs) concentrations were calculated equal to 2.1 and 2.6 ng g⁻¹ for sea and rock salts, respectively. Environmental interactions of salt production with trace elements and PAHs are also discussed.
اظهر المزيد [+] اقل [-]Functional rGO aerogel as a potential adsorbent for removing hazardous hexavalent chromium: adsorption performance and mechanism النص الكامل
2020
Chen, Jingda | Liang, Qianwei | Ploychompoo, Sittipranee | Luo, Hanjin
A novel functional rGO aerogel was synthesized by a facile hydrothermal method. In this process, graphene oxide (GO) was used as the precursor and oxidant to synthesize the aerogels. Ethylenediaminetetraacetic acid disodium salt (EDTA-2Na) and pyrrole monomer (reducing agent) were selected to use as hole scavenger and nitrogen sources. The obtained EDTA-2Na/polypyrrole (Ppy)/rGO aerogel (EPGA) has a high adsorption capacity for Cr(VI) anions, and the maximum adsorption capacity reached 361 mg/g at 298 K at pH of 2. In addition, EPGA exhibited a good ability to selectively remove Cr(VI) anions under the effect of coexisting ions (Cl⁻, NO₃⁻, SO₄²⁻, PO₄³⁻, Ni⁺, Cu²⁺, Zn²⁺, and Cd²⁺) and good regeneration ability. The kinetics process and adsorption isotherm can be fitted well with the pseudo-second-order kinetic model and Freundlich isotherm model, respectively. The removal mechanism involved electrostatic interaction, reduction, ion exchange, and chelation process. This work provides a simple and environmentally friendly synthetic route for EPGA, which will be a potential candidate for efficient removal Cr(VI) anions from industrial wastewater.
اظهر المزيد [+] اقل [-]Biological activity and safety profile of monoterpenes against Plutella xylostella L. (Lepidoptera: Plutellidae) النص الكامل
2020
Cai, Yuehong | Hu, Xian | Wang, Pan | Xie, Yongjian | Lin, Zhufeng | Zhang, Zhilin
Plutella xylostella L. is a cosmopolitan pest of wild and cultivated crucifer vegetables worldwide. It has developed resistance to almost all commercial chemicals, making them one of the most problematic field pests in China. The natural plant extracts and essential oils (EOs) could be a safe alternative for agricultural pests. The development and production of EOs decrease the negative effects of synthetic chemicals. In the present study, the fumigation activity of 8 pure monoterpenes against P. xylostella was evaluated. Results from fumigation tests revealed that 8 tested compounds exhibited various degrees of toxicity against adults of the diamondback moth. Cuminaldehyde was the most toxic compound based on the 12-h LC₅₀ (0.17 mg/L) and 24-h LC₅₀ (0.12 mg/L) values, respectively. Also for larvae and eggs, cuminaldehyde was the most toxic compound. The 12-h LC₅₀ value for cuminaldehyde to 1st, 2nd, and 3rd instar larvae was 0.10 mg/L, 0.12 mg/L, and 0.55 mg/L, respectively. The 24-h LC₅₀ value for the different instar larvae was 0.07 mg/L, 0.09 mg/L, and 0.35 mg/L, respectively. The 24-h LC₅₀ value for eggs (endpoint hatching rate) was 1.95 mg/L for cuminaldehyde, followed by carvacrol and eugenol (2.05 mg/L and 2.31 mg/L, respectively). Cuminaldehyde was very friendly to the larvae and adults of Harmonia axyridis and did not cause any mortality. Our results indicated that cuminaldehyde had potential insecticidal activity against P. xylostella and could be utilized in the novel biological pesticide development.
اظهر المزيد [+] اقل [-]Accumulation of organic carbon in a large canyon reservoir in Karstic area, Southwest China النص الكامل
2020
Qin, Yong | Hao, Feng | Zhang, Dong | Lang, Yunchao | Wang, Fushun
Artificial reservoirs play an important role in intercepting organic carbon (OC), which affects the carbon cycle of inland waters. However, limited by the methods of field observations, studies on the potential carbon sink of sediment in reservoirs are not accurate enough. In this study, we investigated OC accumulation in the Wujiangdu Reservoir (WJDR), a canyon reservoir located in a karst area of Southwest China, by coupling seismic survey data with physicochemical data of sediment cores. The results showed that irregular underwater topography resulted in spatial heterogeneity of the sediment deposition. The mean OC accumulation rate in the WJDR was 579.2 g C m⁻² year⁻¹, and the OC accumulation flux of the WJDR was 1.4 × 10¹⁰ g C year⁻¹. δ¹³C values coupled with a mixing model indicated that the autochthonous OC ranged from 14.2 to 97.0% of the total OC in the sediment, with an average of 48.4%. The significantly positive relationship between autochthonous OC and TN indicated that the autochthonous OC generated in the reservoir was associated with nutrient input. The autochthonous OC accumulation flux was 6.6 × 10⁹ g C year⁻¹, which was equal to 2.3 times the carbon emission from the reservoir surface to the atmosphere as CO₂-C, indicating that the autochthonous OC produced within the reservoir is a large carbon sink.
اظهر المزيد [+] اقل [-]Pollution characteristics, sources, and health risk assessments of urban road dust in Kuala Lumpur City النص الكامل
2020
Othman, Murnira | Latif, Mohd Talib
Urban road dust contains anthropogenic components at toxic concentrations which can be hazardous to human health. A total of 36 road dust samples from five different urban areas, a commercial (CM), a high traffic (HT), a park (GR), a rail station (LRT), and a residential area (RD), were collected in Kuala Lumpur City followed by investigation into compositions, sources, and human health risks. The concentrations of trace metals in road dust and the bioaccessible fraction were determined using inductively couple plasma-mass spectrometry (ICP-MS) while ion concentrations were determined using ion chromatography (IC). The trace metal concentrations were dominated by Fe and Al with contributions of 53% and 21% to the total trace metal and ion concentrations in road dust. Another dominant metal was Zn while the dominant ion was Ca²⁺ with average concentrations of 314 ± 190 μg g⁻¹ and 3470 ± 1693 μg g⁻¹, respectively. The most bioaccessible fraction was Zn followed by the sequence Sr > Cd > Cr > Cu > Ni > Co > Mn > As > V > Pb > Fe > Al > U. The results revealed that the highest trace metal and ion concentrations in road dust and in the bioaccessible fraction were found at the LRT area. Based on the source apportionment analysis, the major source of road dust was vehicle emissions/traffic activity (47%), and for the bioaccessible fraction, the major source was soil dust (50%). For the health risk assessments, hazard quotient (HQ) and cancer risk (CR) values for each element were < 1 and in the tolerable range (1.0E-06 to 1.0E-04), except for As for the ingestion pathway. This result suggests a low risk from non-carcinogenic and probable risk from carcinogenic elements, with higher health risks for children compared to adults.
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