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Результаты 5441-5450 из 6,560
Gallic acid affects blood-brain barrier permeability, behaviors, hippocampus local EEG, and brain oxidative stress in ischemic rats exposed to dusty particulate matter Полный текст
2020
Mirshekari Jahangiri, Hamzeh | Sarkaki, Alireza | Farbood, Yaghoob | Dianat, Mahin | Goudarzi, Gholamreza
Dust storms are environmental natural events that transport high concentrations of particulate matter (PM) in living spaces. Recent epidemiological studies have shown that air pollution is associated with stroke. In the present study we aimed to investigate the probable protective effects of gallic acid (GA) on blood-brain barrier (BBB) disruption, brain oxidative stress, anxiety, depression, locomotion behaviors, and changes of hippocampal local electroencephalogram (local EEG) power induced by 4-vessel transient occlusion (4VO I/R) following exposure to dusty PM in rats. Male Wistar rats were divided randomly into eight groups: (1) vehicle+Sham (Veh + Sh), (2) vehicle+4VO I/R (Veh + I/R), (3) gallic acid+sham (GA + Sh), (4) gallic acid+4VO I/R (GA + I/R), (5) vehicle+PM (Veh + PM), (6) PM + 4VO I/R (PM + I/R), (7) gallic acid+PM + Sham (GA + PM + Sh), and (8) gallic acid+PM + 4Vo I/R (GA + PM + I/R). 4VO type of I/R was induced after 10 days of pretreatment by GA 100 mg/kg/2 ml/ip, or 2 ml/kg/ip, normal saline as vehicle (Veh) and exposure to dust storm composed of dusty PM (DPM, 2000–8000 μg/m3), 60 min daily for consecutive 10 days) simultaneously. Seventy-two hours after I/R induction, all behavioral tests and BBB permeability evaluation were done. Hippocampus local EEG was recorded just before and 72 h after I/R induction, and finally brain tissue oxidative stress was assayed. Data showed that 4VO I/R following exposure to DPM increased BBB permeability (p < 0.001), brain oxidative stress (p < 0.001), induced anxiety (p < 0.001), depression (p < 0.01), locomotion impairment (p < 0.001), superoxide dismutase (SOD) activity, and local EEG power also were decreased in PM + Sh (p < 0.001). Pretreatment with GA reversed BBB permeability and MDA. Our findings suggest that GA is a probable protective agent against adverse effects of both I/R and exposure to DPM and also in I/R subjects exposed to DPM. The beneficial effects of GA may induce by its antioxidative and anti-inflammatory properties.
Показать больше [+] Меньше [-]Ultrasonication favors TiO2 nano-particles dispersion in PVDF ultrafiltration membrane to effectively enhance membrane hydrophilicity and anti-fouling capability Полный текст
2020
Xie, Wanying | Li, Ji | Sun, Feiyun | Dong, Wenyi
The influence of ultrasonication on membrane performance was investigated by two ultrasonication modes, direct and indirect ultrasonication as pretreatment, and simply improved PVDF-TiO₂ membranes’ performance was systematically compared. Ultrasound intensity of 100% and ultrasonication time ranged from 1 to 2 h positively affect membrane permeability. Characterization results manifested that membrane structure was eventually optimized with an even nano-TiO₂ dispersion by direct ultrasonication. Analysis of surface roughness reflected that PVDF-TiO₂ (MS-U2) surface morphological pattern was peak-valley structure that resisted fouling greatly. A good fitting of experimental result and Tansel’s simulation illustrated that anti-fouling ability was realized direct ultrasonication modified membrane. PVDF-TiO₂ (MS-U2) membrane showing the lowest |τ| reflecting the time required to reach a certain level of the fouling degree was the lowest. Relying upon modified Hermia’s model analysis, protein blockage within the membrane pore was one major fouling mechanism; surface blockage degree of PVDF-TiO₂ (MS-U2) was relative slight. Fouling mechanism analyzed by two models reflected that PVDF-TiO₂ (MS-U2) membrane exhibited a higher anti-protein fouling ability during cross-flow filtration process.
Показать больше [+] Меньше [-]A study on carbon transfer and carbon emission critical paths in China: I-O analysis with multidimensional analytical framework Полный текст
2020
Wen, Lei | Zhang, Yixin
As environmental issues aggravated heavily, China faces increasing pressure and challenges on carbon emission reduction and distribution. we used non-competitive input-output table (I-O table) combined with the methods of Structural Path Analysis (SPA) and Multidimensional Analytical Framework (MAF), based on the data of China in 2012, to analyze the current situation of inter-sector carbon emission transfer and identify the key sectors and the critical paths from multiple perspectives. Our results show that total fixed capital formation is the main final demand. The electricity, petroleum, and metal smelting are the largest carbon outflow sectors, which emit carbon at the upstream of the path. Construction and other services are the most obvious carbon inflow sectors, which belong to the middle and downstream of the path and lead to indirect carbon emissions through their demands for other sectors. “Metal smelting → Construction → Total fixed capital formation,” “Nonmetallic products → Construction → Total fixed capital formation,” and “Petroleum → Urban consumption,” “Electricity → Urban consumption” are the top four paths with large carbon emission, which deserve attention. Finally, this paper puts forward some policy implications on emission reduction based on the results.
Показать больше [+] Меньше [-]Magnetic-activated carbon composites derived from iron sludge and biological sludge for sulfonamide antibiotic removal Полный текст
2020
Wan, Junli | Ding, Jian | Tan, Wanchun | Gao, Yinghong | Sun, Shiquan | He, Chunbo
Novel magnetic-activated carbon composites (MACs) were synthesized via coupling of a glucose-assisted hydrothermal pretreatment and subsequent thermal treatment using iron sludge and biological sludge. The adsorption properties of MACs for sulfonamide antibiotic removal from aqueous solution were investigated. Results revealed that the MACs had a high specific surface area with well-distributed magnetic nano-sized Fe₃O₄/Fe⁰ particles with a graphitic shell. This finding indicates that the ferric compounds in the iron sludge were not only converted into magnetic ferrite but also worked as activators for graphitization of the surrounding amorphous carbon. The pseudo-second-order kinetics and Langmuir models were shown to well fit sulfonamide antibiotic adsorption on the MACs. There was a high correlation between the kₗ·qₘ and physicochemical parameters of the sulfonamides. The three parameters are molecular polarizability, octanol-water partition coefficient, and solubility, respectively. The sulfonamide adsorption by the MACs was highly pH dependent. Hydrophobic interaction, π-π interaction, as well as electrostatic interaction, played dominant roles in the sulfonamide adsorption.
Показать больше [+] Меньше [-]Research on the strategic interaction of China’s regional air pollution regulation: spatial interpretation of “incomplete implementation” of regulatory policies Полный текст
2020
Song, Yan | Zhang, Xiao | Zhang, Ming
Research on the current strategic interaction of local governments in air pollution control is a key breakthrough. Based on the theory of Chinese style decentralization, this paper puts forward a theoretical framework to explain the incomplete enforcement of air pollution regulation. Using the panel data of 30 provinces in China from 2004 to 2016, this study employs spatial Durbin model, empirically tested the inter-regional strategic interaction of air pollution regulation, and further explores the effect of performance assessment indicators on this strategic interaction. The main conclusions of this paper are as follows: (1) Empirical results confirm that adjacent provinces do exist strategic interaction of air pollution regulation. Furthermore, the strategic interaction of air pollution regulation belongs to complementarities. (2) Meanwhile, from a regional perspective, due to the low level of economic development stock and the low level of air pollution, the interaction effect of air pollution regulation strategies in northwestern region is weaker than that in southeastern region. (3) In addition, under the national sample and the southeast sample, the air environment performance assessment indicators weaken the inter-regional strategic interaction of air pollution regulation, and economic performance assessment indicators on the contrary.
Показать больше [+] Меньше [-]Modeling the temporal distribution of water, ammonium-N, and nitrate-N in the root zone of wheat using HYDRUS-2D under conservation agriculture Полный текст
2020
Shafeeq, Poo Madhathil | Aggarwal, Pramila | Krishnan, Prameela | Rai, Vikas | Pramanik, Pragati | Das, Tapas Kumar
In the current study, the temporal distribution of both soil water and soil NO₃–N under several conservation agriculture (CA) practices during the wheat crop growth were characterized by HYDRUS-2D model. Treatments comprised of conventional tillage (CT), permanent broad beds (PBB), zero tillage (ZT), PBB with residue (PBB+R) and ZT with residue (ZT+R). Hydraulic inputs of the model, comprising the measured value of Kfₛ, α and n, obtained as the output of Rosetta Lite model were optimized through inverse modeling. Model predicted the daily change in soil water content (SWC) of the profile during the simulated period (62–91 DAS) with good accuracy (R² = 0.75; root mean squared error (RMSE) = 0.038). In general, soil water balance simulated from the model showed 50% lower cumulative drainage, 50% higher cumulative transpiration along with higher soil water retention, in PBB+R than CT. Reported values of the first-order rate constants, signify nitrification of urea to NH₄–N (μₐ) (day⁻¹) nitrification of NH₄–N to NO₃–N (μₙ) (day⁻¹) and the distribution coefficient of urea (Kd−in cm³ mg⁻¹) were optimized through inverse modeling. Later they were used as solute transport reaction input parameters of the model, to predict the daily change in NO₃–N of the profile with better accuracy (R² = 0.83; RMSE = 4.62). Since NH₄–N disappears fast, it could not be measured frequently. Therefore, not enough data could be generated for their use in the calibration and validation of the model. Results of simulation of daily NO₃–N concentration indicated a higher concentration of NO₃–N in the surface layer and its leaching losses beyond the root zone were relatively lesser in PBB+R, than CT, which resulted in less contamination of the belowground water. Thus, the study clearly recommended PBB+R to be adopted for wheat cultivation in maize–wheat cropping system, as it enhances the water and nitrogen availability in the root zone and reduce their losses beyond the root zone.
Показать больше [+] Меньше [-]Metal concentration and health risk assessment of fifteen wild mushrooms collected from the Ankara University Campus (Turkey) Полный текст
2020
Sarikurkcu, Cengiz | Sarikurkcu, Rifat Tayyib | Akata, Ilgaz | Tepe, Bektas
The aim of this study is to analyze Fe, Mn, Cu, Zn, Co, Cd, Pb, and Ni contents of Cyclocybe cylindracea, Armillaria mellea, Bjerkandera adusta, Rheubarbariboletus armeniacus, Coprinellus disseminatus, C. micaceus, C. comatus, Inonotus hispidus, Lepista nuda, Leucoagaricus leucothites, Pleurotus ostreatus, Cerioporus squamosus, Schizophyllum commune, Scleroderma verrucosum, and Trametes trogii collected from the Ankara University Besevler 10th Year Campus (Turkey), an area where human settlement and traffic are intense. In addition to the elemental analysis, the daily intake of metal (DIM) and health risk index (HRI) values of the edible ones were also calculated. Fe, Mn, Cu, Zn, Co, Cd, Pb, and Ni concentrations of the samples were found to be 112.0–5079.0, 3.0–124.0, 4.0–77.0, 2.0–196.0, 0.18–2.98, 0.18–5.3, 0.04–10.98, and 0.22–8.23 mg/kg dry weight, respectively. As a result of DIM and HRI analysis, C. cylindracea, L. nuda, and C. squamosus were found to be within the reference dose limits determined by competent authorities and can be safely consumed in terms of all metals studied. However, the Cd, Co, and Fe contents of C. micaceus were found to be above 1.0 (1.06, 4.25, and 7.06, respectively). In addition, it has been found that A. mellea, R. armeniacus, C. comatus, L. leucothites, and P. ostreatus are toxic in terms of Cd/Co, Fe/Pb, Co/Fe, Cd, and Fe contents, respectively. As the area in question is a traffic intensive area, it has been concluded that the emissions of the vehicles should be controlled in terms of legal limits and that the consumption of some mushrooms in this region should not be preferred until necessary measures are taken.
Показать больше [+] Меньше [-]Exploring the phytoremediation potential of Cynara cardunculus: a trial on an industrial soil highly contaminated by heavy metals Полный текст
2020
Capozzi, Fiore | Sorrentino, Maria Cristina | Caporale, Antonio Giandonato | Fiorentino, Nunzio | Giordano, Simonetta | Spagnuolo, Valeria
Metal uptake capacity and growth patterns of three cardoon cultivars (Sardo, Siciliano, and Spagnolo) were investigated for phytoremediation in a metal-contaminated soil. Metal concentrations after one and two growth rounds were measured in soil and plants by ICP-MS. Potentially and promptly available metal fractions were estimated by EDTA and ammonium nitrate. Plant weight, water and nitrogen content, and life span were considered as growth parameters. After the first growth cycle, a significant accumulation of all elements was observed in roots, whereas only Cd, Cu, Fe, Pb, and Sb were significantly translocated to the shoots. After the second growth cycle, a further significant increase, especially in roots, was observed in all cultivars and for all elements considered. High percentages of the potentially available fraction were found for As, Cd, Cu, Pb, and Sb. Metal concentrations in plants were far higher than the promptly available fraction, indicating an increase of metal bioavailability during culture rounds. A severe decrease of weight and life span was observed in Sardo and Siciliano grown on polluted soil, along with an increase in N content. The cultivar Spagnolo, harmonizing a high ability of metal uptake and tolerance, proved the most efficient cultivar in metal phytoremediation.
Показать больше [+] Меньше [-]Comparison of capping and mixing of calcined dolomite and zeolite for interrupting the release of nutrients from contaminated lake sediment Полный текст
2020
Alvarado, Jesteen Naldo | Hong, Seung-Hee | Lee, Chang-Gu | Park, Seong-Jik
This study aimed to assess the effectiveness of capping and mixing of calcined dolomite and zeolite for the remediation of sediment contaminated with nitrogen (N) and phosphorus (P). Laboratory incubation experiments were performed to monitor the release of NH₄-N, NO₃-N, T-N, PO₄-P, and T-P from the sediment. pH, electric conductivity (EC), oxidation reduction potential (ORP), and dissolved oxygen (DO) in overlying water for 60 days were evaluated. Dolomite-amended sediment has high pH and EC. Zeolite and dolomite capping effectively interrupted the release of N and P, respectively; capping was found to be more effective than mixing. The mixture of dolomite and zeolite was also effective; however, their efficiencies were influenced by their placement. The remediation efficiencies when the dolomite was placed above the zeolite cap layer (DOL/ZEO_CAP) were 95.9%, 101.6%, and 100.2% for NH₄-N, PO₄-P, and total, and the total remediation efficiency of DOL/ZEO_CAP was twice that of the opposite placement (ZEO/DOL_CAP). Low remediation efficiencies for NH₄-N and T-N were observed in ZEO/DOL_CAP because NH₄⁺ adsorption on zeolite was hindered by Ca²⁺ and Mg²⁺ released from the dolomite. The combination of dolomite and zeolite can be used as a capping material for simultaneously interrupting the release of both nitrogen and phosphorus, but their placement should be considered.
Показать больше [+] Меньше [-]Organochlorine pesticides in feathers of three raptor species in southern Brazil Полный текст
2020
Aver, Gustavo Francisco | Espín, Silvia | Dal Corno, Renata De Boni | García-Fernández, Antonio Juan | Petry, Maria Virginia
In this study, we determined the presence of organochlorine pesticides (OCPs) in back feathers from three raptor species, Phalcoboenus chimango, Milvago chimachima and Caracara plancus. Samples were obtained from live animals and ten OCPs were detected: α-HCH, β-HCH and γ-HCH (lindane), heptachlor, heptachlor epoxide, aldrin, endosulfan I, endosulfan II, endosulfan sulfate and p,p′-DDE. The concentrations found were higher than those reported in other raptor species, and C. plancus showed greater values than P. chimango and M. chimachima for all the substances. These differences may be justified by the species feeding habits and the characteristics of the sampling area, since C. plancus were sampled in an area with a higher concentration of agricultural crops and urbanized environments. In relation to the possible negative effects, four individuals of C. plancus presented DDE values related to sublethal effects for other species. This is the first study reporting OCPs in back feathers of these species in Brazil, and further studies evaluating OCP exposure and related effects are important for a better understanding of the consequences of different OCP concentrations on the health of these species.
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