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Resultados 4481-4490 de 4,937
Cyhalothrin biodegradation in Cunninghamella elegans Texto completo
2019
Palmer-Brown, William | de Melo Souza, Paula Letícia | Murphy, Cormac D.
The insecticide λ-cyhalothrin was incubated with planktonic and biofilm cultures of the fungus Cunninghamella elegans. ¹⁹F nuclear magnetic resonance spectroscopy demonstrated that the compound was initially biosorbed to the biomass and more slowly degraded by the fungus. Furthermore, the presence of trifluoromethyl-containing metabolites was observed. Analysis of culture extracts by gas chromatography-mass spectrometry (GC-MS) identified non-fluorinated metabolites that suggested the likely catabolic pathway. The hydroxylated metabolites were probably generated from the action of cytochromes P450 (CYPs), as the presence of CYP inhibitors resulted in the absence of biodegradation. Planktonic cells were measurably faster at degrading the pesticide compared with biofilm.
Mostrar más [+] Menos [-]Sorption of 14C-carbofuran in Austrian soils: evaluation of fate and transport of carbofuran in temperate regions Texto completo
2019
Cáceres, Tanya | Maestroni, Britt | Islam, Marivil | Cannavan, Andrew
Carbofuran is an anticholinesterase carbamate commonly used as an insecticide, nematicide and acaricide in agricultural practice throughout the world. However, data on its sorption in temperate soils from Europe is limited. Laboratory studies were conducted to determine the adsorption of carbofuran on three distinct Austrian soils using batch experiments and radiometric techniques. Carbofuran adsorption capacity of the soils was found to be low in the three soils tested and showed to be related to the soils clay and organic carbon contents. The pesticide presented linear adsorption isotherms in all of the three soils. Due to the low sorption of carbofuran in the soils tested and to its high water solubility, there is a risk of migration to water bodies through run off and consequent negative effects on aquatic organisms and soil biota.
Mostrar más [+] Menos [-]Effects of food-borne ZnO nanoparticles on intestinal microbiota of common carp (Cyprinus carpio L.) Texto completo
2019
Chupani, Latifeh | Bárta, Jiří | Zuskova, Eliska
Ingestion of nanoparticles (NPs) with antimicrobial properties may disrupt the balance of intestinal microbiota. To investigate the effects of zinc oxide (ZnO) NPs on intestinal flora, common carp Cyprinus carpio were fed a commercial feed containing 500 mg kg⁻¹ ZnO NPs for 6 weeks and compared to a control group receiving a similar feed-only regime. Sequencing data were analyzed both in individual fish and in pooled samples. Sequencing of 16S rRNA encoding gene of individual specimens revealed high variation in intestinal microbial composition. Assessment of pooled results can obscure high individual variation in data. ZnO NPs consumption was not associated with a significant difference in the intestinal microbial community compared to untreated controls. Our results indicated a high individual variation in the intestinal microbiome, which may further point out the importance of functional study over microbial composition to address nanomaterials-microbiome relationship.
Mostrar más [+] Menos [-]Ammonia and greenhouse gas emissions following the application of clinoptilolite on the litter of a breeding hen house Texto completo
2019
Pereira, José L. S. | Ferreira, Silvia | Pinheiro, Victor | Trindade, Henrique
The husbandry of chicken for meat generates high levels of gases, being a serious problem for the health of birds and workers as well as for the environment. The aim of the present study was to assess the effect of clinoptilolite as litter additive on the concentrations and emissions of ammonia (NH₃), nitrous oxide (N₂O), carbon dioxide (CO₂), and methane (CH₄) from a breeding hen house under Mediterranean climate conditions. Two similar breeding hen houses were selected, and one house was assigned as control whereas the other house was treated with clinoptilolite as a litter additive. Data were collected during the winter season, in two occasions, first between 26 November and 18 December 2017 and second from 1 to 20 February 2018. Results showed that the application of clinoptilolite on the litter of a breeding hen house reduces the NH₃ and N₂O losses in 28 and 34%, respectively, but appears to have no effect on CO₂ losses. In addition, the in-house CH₄ concentrations were below the detection limits.
Mostrar más [+] Menos [-]Total salinity elimination during preservation of animal skins: a sustainable approach through benign alternatives Texto completo
2019
Sundar, John | Muralidharan, Chellappa
Use of sodium chloride to preserve animal skins and hides is becoming increasingly untenable due to stringent environmental regulations. In the present research work, a combination of sparingly soluble alkali and water-soluble polymer of ethylene oxide has been used to preserve skins with an objective of total elimination of common salt for preservation. A comprehensive study has been made for evaluating various parameters, such as dehydration and rehydration behaviours of skins, microbial growth, emission loads and physico-chemical characteristics of the cured skin to validate the salt-free preservation system developed. The shrinkage temperature, denaturation temperature and mechanical strength of tanned leather were analysed by using shrinkage, differential scanning calorimetric and thermomechanical analysis techniques. The new curing system has been found to be effective in preserving the skin as indicated by the various parameters studied and the final leather quality. The significant reduction in total solids content such as dissolved solids and suspended solids present in the effluent compared to conventional preservation method is evident from environmental impact assessment studies.
Mostrar más [+] Menos [-]Preparation of carbonaceous materials from pyrolysis of chicken bones and its application for fuchsine adsorption Texto completo
2019
Côrtes, Letícia Nascimento | Druzian, Susanne Pedroso | Streit, Angélica Fátima Mantelli | Sant’anna Cadaval Junior, Tito Roberto | Collazzo, Gabriela Carvalho | Dotto, Guilherme Luiz
Activated carbon and biochar were obtained from chicken bone (CB), characterized, and applied to remove basic fuchsine from aqueous media. The adsorbent dosage and pH effects were studied, as well as kinetic, equilibrium, and thermodynamic curves were constructed. The values of BET surface area and total pore volume were 108.94 m² g⁻¹ and 0.219 cm³ g⁻¹ for the activated carbon and, 18.72 m² g⁻¹ and 0.075 cm³ g⁻¹ for the biochar. The dye removal percentages were 93.63 and 55.38% when 2.5 g L⁻¹ of activated carbon and biochar were used, respectively. The adsorption was favored using 0.5 g L⁻¹ of adsorbent and pH of 7.0. Adsorption kinetics was well represented by the pseudo-second-order model. Langmuir model was the best to represent the equilibrium. Maximum adsorption capacity was 260.8 mg g⁻¹, obtained using activated carbon. The process was endothermic, favorable, and spontaneous. Results showed that alternative carbonaceous materials can be obtained from chicken bones and used as adsorbents to treat colored effluents containing fuchsine.
Mostrar más [+] Menos [-]Potential role of N-acetylcysteine on chlorpyrifos-induced neurotoxicity in rats Texto completo
2019
Mahmoud, Sahar M. | Abdel Moneim, Ahmed E. | Qayed, Marwa M. | El-Yamany, Nabil A.
Chlorpyrifos (CPF) is a widely used organophosphate insecticide with several harmful effects. N-acetylcysteine (NAC) represents an ideal antixenobiotic; it can directly enter endogenous biochemical processes and is used as adjunctive treatment for psychiatric disorders. We aimed to evaluate the neuroprotective effect of NAC as an antioxidant drug against CPF-induced neurotoxicity in adult male albino rat brains. Twenty-eight male Wister rats were allocated into four groups (n = 7) and were administered the following for 28 days: group I (control group), physiological saline (0.9% NaCl); group II (CPF group), 10 mg/kg body weight (BW) CPF; group III (NAC group), 100 mg/kg BW NAC; and group VI (CPF+NAC group), NAC 1 h before CPF. CPF intoxication resulted in acetylcholinesterase inhibition, reduced glutathione content, and elevated levels of malondialdehyde and nitric oxide, which are oxidative stress biomarkers. CPF also depleted the activity of antioxidant enzymes, superoxide dismutase and catalase, and levels of inflammatory mediators, tumor necrosis factor-α, interleukin (IL)-6, and IL-1β. Levels of vascular endothelial growth factor, Bax, and the proapoptotic caspases-3 also increased, while brain-derived neurotrophic factor level decreased. Additionally, CPF significantly diminished Bcl-2 (an antiapoptotic protein) in rat brain cortical tissue. NAC treatment was found to protect brain tissue by reversing the CPF-induced neurotoxicity. Our results show the antioxidant, antiinflammatory, and antiapoptotic effects of NAC on CPF-induced neurotoxicity in rat brain tissue.
Mostrar más [+] Menos [-]Convergence analysis of China’s energy intensity at the industrial sector level Texto completo
2019
Huang, Junbing | Zheng, Xuemei | Wang, Ailun | Cai, Xiaochen
China’s industrial energy consumption accounted for approximately 70% of national energy demand in the past four decades. Regarding energy demand and environmental pollution, success in controlling energy demand and reducing energy intensity for industrial sectors in China would play a crucial role for the country’s sustainable growth problems. To formulate targeted energy plans, the features and characters of China’s industrial energy intensity should be carefully evaluated. In this study, a carefully designed econometric model that considers different technological factors including indigenous R&D and technology spillovers from foreign direct investment and trade under a united framework is applied to investigate the β-convergence characteristics for China’s industrial energy intensity by employing a panel dataset covering China’s 34 industrial sectors over 2000–2010. The results verify the existence of β-convergence in industrial energy intensity during the sample period. For the industrial sectors overall and the light industrial sectors, the empirical results indicate that indigenous R&D and technology spillovers from FDI and imports are beneficial in curbing energy intensity. However, technology spillover through exports makes it harder to reduce energy intensity. In addition, not all technological factors have played a significant role in reducing energy intensity for the heavy industrial sectors.
Mostrar más [+] Menos [-]The influence of moisture content on the production of odor from food waste using path analysis Texto completo
2019
Qamaruz-Zaman, Nastaein | Abdul-Sukor, Nur Sabahiah | Ab.-Rahman, Siti Aishah | Yaacof, Nurashikin
Path analysis has been largely used in marketing research but has recently been applied in an environmental management context. This study evaluated the potential of path analysis in identifying the influence of moisture content on odor from decomposing food waste. Food waste with varying moisture content was monitored for odor concentration, microbial population density, oxygen uptake rate, volatile fatty acids, ammonia, and hydrogen sulfide. These various parameters were later analyzed using SmartPLS 3.0 software to produce the path analysis model using simultaneous equation modeling. Results indicate that odor concentration of food waste was not directly affected by moisture content (not significant, t-statistical 1.46 < 1.96), rather; moisture content influenced the microbial population density and biodegradability of the food residue which influenced the formation of hydrogen sulfide (significant, t-statistical 3.79 > 1.96) and subsequently odor. In order to manage food waste–related odors, it is recommended that the waste be kept at a moisture content lower than 40%. This is especially critical if prolonged storage is unavoidable.
Mostrar más [+] Menos [-]Sub-lethal effects of lufenuron exposure on spotted bollworm Earias vittella (Fab): key biological traits and detoxification enzymes activity Texto completo
2019
Hafeez, Muhammad | Jan, Saad | Nawaz, Muhammad | Ali, Ehsan | Ali, Bahar | Qasim, Muhammad | Fernández-Grandon, G Mandela | Shāhid, Muḥammad | Wang, Mo.
Spotted bollworm, Earias vittella, is one of the most serious and devastating insect pests of vegetables and cotton. Currently, insecticides are necessary for its control in nearly all crop systems. In this paper, we evaluate the sub-lethal effects of lufenuron on biological traits and activity of detoxification enzymes: cytochrome P450 monooxygenases, esterase, and glutathione S-transeferase (GST) in second instar larvae of E. vittella. Results showed that sub-lethal concentrations (LC₁₅ and LC₄₀ of lufenuron), prolonged larval period (at LC₄₀ = 13.86 ± 1.22 day, LC₁₅ = 13.14 ± 1.15 day, control = 12.28 ± 0.7), pupal duration (LC₄₀ = 11.1 ± day, LC₁₅ = 11.8 ± 0.28 day, control = 9.40 ± 0.52), and extended mean generation time (LC₄₀ = 27.3 ± 0.43 LC₁₅ = 29.0 ± 1.19 day, control = 26.0 ± 0.65). Sub-lethal exposure significantly prolonged the pre-adult stage, decreased pupal weight, and reduced adult longevity in the parent (F₀) and F₁ generation. Moreover, the fecundity and egg viability were significantly lowered in parental and F₁ generations at both sub-lethal concentrations compared to the control. While no significant effects were noted on reproductive parameters such as the intrinsic rate of increase (r), finite rate of increase (λ), and net reproduction rate (R₀) of F₁ generation when compared to the control. Only mean generation time (T) in F₁ at LC₁₅ was significantly longer compared to the LC₄₀ and control (LC₄₀ = 3.79 ± 0.37, LC₁₅ = 32.28 ± 1.55 day, control = 29.79 ± 0.55). Comparatively, the activities of cytochrome P450 monooxygenases and esterase were higher than GST in treated populations. The increase in resistance development against insecticides may possibly because of elevated activity of detoxification enzymes. These results provide useful information for monitoring resistance in integrated pest management (IPM) programs for E. vittella.
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