Refine search
Results 2881-2890 of 7,290
The role of Musca domestica and milk in transmitting pathogenic multidrug-resistant Escherichia coli and associated phylogroups to neonatal calves Full text
2022
Bakry, Noha | ʻAwaḍ, Walīd | Ahmed, Samia | Kamel, Mohamed
Escherichia coli, as a global source of antimicrobial resistance, is a serious veterinary and public health concern. The transmission of pathogenic multidrug-resistant (MDR) E. coli within diarrheic calves and its correlation with Musca domestica and milk strains have been investigated. In total, 110, 80, and 26 E. coli strains were obtained from 70 rectal swabs from diarrheic calves, 60 milk samples and 20 M. domestica, respectively. Molecular pathotyping of E. coli revealed the presence of pathogenic E. coli with a higher percentage of shigatoxigenic strains within diarrheic calves and M. domestica at 46.4% and 34.6%, respectively. Phenotypic antimicrobial resistance revealed higher β-lactams resistance except for cefquinome that exhibited low resistance in M.domestica and milk strains at 30.8% and 30%, respectively. The extended-spectrum cephalosporin (ESC) resistant strains were detected within fecal, M. domestica, and milk strains at 69.1%, 73.1%, and 71.3%, respectively. All E. coli strains isolated from M. domestica exhibited MDR, while fecal and milk strains were harboring MDR at 99.1% and 85%, respectively. Molecular detection of resistant genes revealed the predominance of the blaTEM gene, while none of these strains harbored the blaOXA gene. The highest percentages for blaCTXM and blaCMYII genes were detected in M. domestica strains at 53.8% and 61.5%, respectively. Regarding colistin resistance, the mcr-1 gene was detected only in fecal and milk strains at 35.5% and 15%, respectively. A high frequency of phylogroup B2 was detected within fecal and M. domestica strains, while milk strains were mainly assigned to the B1 phylogroup. Pathogenic E. coli strains with the same phenotypic and genotypic antimicrobial resistance and phylogroups were identified for both diarrheic calves and M. domestica, suggesting that the possible role of M. domestica in disseminating pathogenic strains and antimicrobial resistance in dairy farms.
Show more [+] Less [-]A stochastic approach for the assessment of suspended sediment concentration at the Upper Rhone River basin, Switzerland Full text
2022
Vaheddoost, Babak | Vazifehkhah, Saeed | Safari, Mir Jafar Sadegh
This study addresses the link between suspended sediment concentration, precipitation, streamflow, and direct runoff components. This is important since suspended sediment concentration in the streamflow has invaluable importance in the management of the river basin. For this, the daily streamflow time series in five consecutive stations at Upper Rhone River Basin, a relatively large basin in the Alpine region of Switzerland, daily precipitation at one station, and the twice a week suspended sediment concentration records at the most downstream station between January 1981 and October 2020 are used. Initially, the base flow and the direct runoff associated with streamflow time series are obtained using the sliding interval method. Elasticity analyses between streamflow and suspended sediment concentration together with correlation, autocorrelation, partial autocorrelation, stationarity, and homogeneity are examined by the Augmented Dickey-Fuller and Pettitt’s tests, respectively. Then, various stochastic scenarios are generated using the autoregressive moving average exogenous method (ARMAX). It is concluded that the precipitation and direct runoff have fewer effects on the suspended sediment concentration at downstream of the river. Hence, the cumulative effect of the glacier or snowmelt and channel erosion may exceed the effect of rain blown washouts on the suspended sediment concentration at the Port du Scex station. It is found that the ARMAX model results are satisfactory and can be suggested for further application.
Show more [+] Less [-]Simultaneous multi-residue pesticide analysis in southern Brazilian soil based on chemometric tools and QuEChERS-LC-DAD/FLD method Full text
2022
do Amaral, Bianca | Peralta-Zamora, Patricio | Nagata, Noemi
A simple and straightforward QuEChERS extraction method was proposed for the simultaneous determination of atrazine (ATZ), desethylatrazine (DEA), desisopropylatrazine (DIA), carbaryl (CBL), carbendazim (CBD), and diuron (DIU) in soil with high agricultural activity from southeastern Brazil, using high-performance liquid chromatography-diode-array detection/fluorescence detection. Screening studies carried out by 2⁴ factorial design indicate better recoveries when less sample (1.0 g) and the volume of solvent (2.0 mL of ACN) were applied, compared to the original QuEChERS method. Furthermore, interactions between factors were not negligible in the experimental set, except for ATZ and DIU, in which only water volume influenced their recovery. The influence of the type (primary secondary amine (PSA), C18, and Florisil) and the sorbent amount ratio to the compounds’ concentration were also considered. PSA (25 mg) was selected as the best sorbent without losing analytical response. The limits of quantification (LOQ) were estimated to be 5.0 to 15 µg kg⁻¹ in the soil matrix. Analytical performances were consistent with linearity (R² ≥ 0.998), recovery from 74.7 to 108%, and relative standard deviations (RSD) between 2.6 and 20.2%. Robustness was assessed by fractional factorial Plackett–Burman design. The method is recommended for chemicals that are soluble in water, and it was successfully applied in the analysis of real soil samples containing the analytes in the range of μg kg⁻¹, proving to be suitable for the study of soils strongly impacted by agricultural activity.
Show more [+] Less [-]Evaluating the nexus between ongoing and increasing urbanization and carbon emission: a study of ARDL-bound testing approach Full text
2022
Ali, Muhammad Abu Sufyan | Yi, Lan
The growing urbanization has created a substantial economic imbalance between the urban and rural households in the world’s emerging economies and put a significant effect on carbon dioxide emissions. Simultaneously, many researchers have grown concerned by the significant consequences of urbanization on carbon emissions. In current research, we make an effort in Pakistan to investigate how urbanization affects the carbon emissions. In order to attain the intended goals of long run and short run investigation, we employed the most appropriate method of auto-regressive distributed lag model for time series data-set, while the vector error correction model, on the other hand, was employed to investigate causation. The estimated findings of the auto-regressive distributed lag model supported the association amongst the model’s selected variables. In long and short run, the estimated findings approved that as the level of urbanization rises, so does the carbon emissions. Furthermore, the estimated results of the vector error correction model acknowledged the validity of short run unidirectional causal relationship from urbanization towards carbon emissions and from carbon emission towards energy consumption, as well as in short run, where economic growth one-way Granger generates the carbon emission. To summarize, based on the current findings, that reflects the significance of the underlined factors. The study recommends that government should prioritize the development of energy efficient and environment friendly strategies with respect to fast growing urbanization to control the carbon emission.
Show more [+] Less [-]Mixture toxicity of six pharmaceuticals towards Aliivibrio fischeri, Daphnia magna, and Lemna minor Full text
2022
Białk-Bielińska, Anna | Grabarczyk, Łukasz | Mulkiewicz, Ewa | Puckowski, Alan | Stolte, Stefan | Stepnowski, Piotr
As the knowledge on the joint effects of pharmaceuticals towards different non-target organisms is still limited, the aim of our study was to evaluate the toxicity of mixtures of pharmaceuticals, as well as their baseline toxicity towards three selected organisms, namely the bioluminescent bacteria Aliivibrio fischeri, the crustacean Daphnia magna, and the duckweed Lemna minor. Different mixtures composed of three up to five pharmaceuticals having the same or different mechanisms of action in terms of their therapeutic activity (non-steroidal anti-inflammatory drugs, opioid analgesic, antibacterial and anti-epileptic drugs) were investigated. The observed EC₅₀s were compared with those predicted using the concentration addition (CA) and independent action (IA) models. In general, the EC₅₀ values for mixtures predicted with the CA model were lower than those obtained with the IA model, although, in some cases, test predictions of these two models were almost identical. Most of the experimentally determined EC₅₀ values for the specific mixtures were slightly higher than those predicted with the CA model; hence, a less than additive effect was noted. Based on the obtained results, it might be concluded that the CA model assumes the worst-case scenario and gives overall closer predictions; therefore, it should be recommended also for modeling the mixture toxicity of pharmaceuticals with different modes of action.
Show more [+] Less [-]Eutrophication and sediment–water exchange of total petroleum hydrocarbons and heavy metals of Hashilan wetland, a national heritage in NW Iran Full text
2022
Abbasi, Sajjad | Sheikh Fakhradini, Sara | Jaafarzadeh, Neamatollah | Ebrahimi, Pooria | Ashayeri, Shirin Yavar
The heavy metal(loid)s concentrations in water and sediments were analyzed in the Hashilan wetland to assess the spatial distribution, pollution status, fate, partitioning, and ecological risk and also to identify the heavy metal(loid)s sources in sediments using PMF (Positive Matrix Factorization) and APCs-MLR (absolute principal component score-multiple linear regression) receptor models. According to the pollution indices, (Ni, Cu, Cr, Mo), and (Zn, Cr, and Cu) are considered the most important pollutants in sediments and water, respectively. Ni, Cr, and Cu are the main contributors to ecological risks in sediments of some stations. The potential ecological risk assessment proposed low ecological risk in water of the study area. Higher distribution coefficient (Kₚ) values of Ni, Cr, Mn, Cu, Co, Pb, As, and Zn indicated the majority of these heavy metals present in the sediments; whereas, the majority of Cd concentration occurs in water. PMF and APCs-MLR results indicated the natural sources were the main factors affecting the concentrations of Ni, Cr, Zn, Al, Co, Fe, Pb, As, Cd and somewhat Cu. Mixed natural and agricultural activities are the main sources of Mo, and somewhat Cu. According to the results, there is low pollution of TPH (total petroleum hydrocarbons) in the sediment samples. Also, phosphate (PO₄²⁻) and nitrate (NO₃⁻) concentrations were below the recommended permissible limits at all sampling sites except the S8 station for NO₃⁻.
Show more [+] Less [-]Numerical study of a building integrated photovoltaic-finned phase change material panel under Tunisian climatic conditions Full text
2022
Nouira, Meriem | Sammouda, Habib
Building-integrated photovoltaic systems’ electrical efficiency decreases when their operating temperature increases. To overcome this drawback, the use of the PCM as a passive method to improve the thermal and electrical performances of the system is highly recommended. Yet pure phase change materials are known for low thermal conductivity. Inserting fins in the PCM enhances its thermal conductivity leading therefore to an improvement in the heat transfer rate. The present investigation carried out the optimization of the BIPV-FPCM system to reduce BIPV system temperature at real Tunisian climatic conditions. The best inclination angle of BIPV-FPCM is carried out. Moreover, the suitable depth of the FPCM box is evaluated. BIPV, BIPV-PCM, and BIPV-FPCM systems are compared. In the present thermodynamic work, the fusion and solidification processes of the FPCM were analyzed. In addition, space between successive fin effect, fin length, and position effect on BIPV electrical and thermal performances had been investigated. Interesting findings showed that the decrease in the tilt angle of the module enhances the heat transfer rate in the FPCM due to the improvement of the convection heat transfer rate in the melted PCM. Thirty degrees is found the most optimal tilt angle with respect to the horizontal where the received solar radiation increases with the decrease of the tilt angle from 90° to 30°. Results prove that the best fin number to enhance performances of the BIPV-PCM system is 3 where 6 cm is found to be the best PCM box depth. Eventually, fin positioning is so important to improve the rate of heat transfer rate by promoting natural convection in the PCM. Results reveal that “full fins” and “front fins” scenarios are the best cases for improving the melting rate and performances of the BIPV-FPCM system.
Show more [+] Less [-]Spirulina platensis protects against microcystin-LR-induced toxicity in rats Full text
2022
Germoush, Mousa O. | Fouda, Maged M. A. | Kamel, Mohamed | Abdel-Daim, Mohamed M.
Microcystis aeruginosa produces an abundant cyanotoxin (microcystins (MCs) in freshwater supplies. MCs have adverse health hazards to animals and humans. Microcystin-leucine-arginine (microcystin-LR or MC-LR) is the most studied among these MCs due to their high toxicity. So, this study was designed to evaluate the possible therapeutic role of the natural algal food supplement, Spirulina platensis (SP), against MC-LR-induced toxic effects in male Wistar rats. Forty rats were randomly divided into five groups. Control and SP groups orally administered distilled water and SP (1000 mg/kg/daily), respectively, for 21 days. MC-LR group was intraperitoneally injected with MC-LR (10 μg/kg/day) for 14 days. MC-LR-SP₅₀₀ and MC-LR-SP₁₀₀₀ groups were orally treated with SP (500 and 1000 mg/kg, respectively) for 7 days and concomitantly with MC-LR for 14 days. MC-LR induced oxidative hepatorenal damage, cardiotoxicity, and neurotoxicity greatly, which was represented by reduction of reduced glutathione content and the activities of glutathione peroxidase, catalase, and superoxide dismutase and elevation of concentrations of nitric oxide and malondialdehyde in renal, hepatic, brain, and heart tissues. In addition, it increased serum levels of urea, creatinine, tumor necrosis factor-alfa, interleukin-1beta and interleukin-6 and serum activities of alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, creatine kinase, and creatine kinase-MB. However, S. platensis restored normal levels of measured serum parameters, ameliorated MC-LR-induced oxidative damage, and normalized tissue antioxidant biomarkers. In conclusion, SP alleviated MC-induced organ toxicities by mitigating oxidative and nitrosative stress and lipid peroxidation.
Show more [+] Less [-]Spatial optimization of the water quality monitoring network in São Paulo State (Brazil) to improve sampling efficiency and reduce bias in a developing sub-tropical region Full text
2022
de Almeida, Ricardo Gabriel Bandeira | Lamparelli, Marta Condé | Dodds, Walter Kennedy | Cunha, Davi Gasparini Fernandes
Water quality monitoring networks (WQMNs) are essential to provide good data for management decisions. Nevertheless, some WQMNs may not appropriately reflect the conditions of the water bodies and their temporal/spatial dimensions, more particularly in developing countries. Also, some WQMNs may use more resources to attain management goals than necessary and can be improved. Here we analyzed the São Paulo State (Brazil) WQMN design in order to evaluate and increase its spatial representativeness based on cluster analysis and stratified sampling strategy focused on clear monitoring goals. We selected water resources management units (UGRHIs) representative of contrasting land uses in the state, with bimonthly data from 2004 to 2018 in 160 river/stream sites. Cluster analysis indicated monitoring site redundancy above 20% in most of the UGRHIs. We identified heterogeneous spatial strata based on land use, hydrological, and geological features through a stratified sampling strategy. We identified that monitoring sites overrepresented more impacted areas. Thus, the network is biased against determination of baseline conditions and towards highly modified aquatic systems. Our proposed spatial strategy suggested the reduction of the number of sites up to 12% in the UGRHIs with the highest population densities, while others would need expansions based on their environmental heterogeneity. The final densities ranged from 1.6 to 13.4 sites/1,000km². Our results illustrate a successful approach to be considered in the São Paulo WQMN strategy, as well as providing a methodology that can be broadly applied in other developing countries.
Show more [+] Less [-]Levels of trace elements and rare earth elements in honey from Jordan Full text
2022
Tahboub, Yahya R. | Al-Ghzawi, Abd Al-Majeed A. | Al-Zayafdneh, Shaker S. | AlGhotani, Mohammad S.
Honey is a common sweetener in the Jordanian diet with an annual consumption of approximately one thousand tons, two-thirds of which are imported. It is believed that the elemental profile of honey is an indicator of safety and botanical and geographic origin. In the literature, there are a lack of studies concerning the levels of major and trace elements in honey in Jordan. A total of 46 elements, including 15 rare earth elements (REEs), were analyzed by inductively coupled plasma-mass spectrometry (ICP-MS) in 18 monofloral and multifloral imported honey samples and 12 multifloral local samples. Regarding monofloral samples, Black Forest samples had the highest total metal content, while acacia samples had the lowest total metal content. Local multifloral honey had the largest Sr and total REE levels, while it had the lowest Mn levels. Very low levels of toxic elements were found in all samples, indicating the safety of honey in Jordan for human consumption. The results of this study showed that a large number of samples (> 100) and the application of advanced statistical models are required to discriminate between multifloral imported and local honey.
Show more [+] Less [-]