خيارات البحث
النتائج 3011 - 3020 من 4,935
Increase of global DNA methylation patterns in beauty salon workers exposed to low levels of formaldehyde النص الكامل
2019
Barbosa, Eduardo | dos Santos, Ana Laura Anibaletto | Peteffi, Giovana Piva | Schneider, Anelise | Müller, Diana | Rovaris, Diego | Bau, Claiton Henrique Dotto | Linden, Rafael | Antunes, Marina Venzon | Charão, Mariele Feiffer
Formaldehyde (FA) is a carcinogenic aldehyde illegally added to creams as a hair straightening agent for the Brazilian blowout (BB). This study aimed to investigate the possible effects of occupational exposure to FA on global DNA methylation in salon workers with different exposure levels. FA exposure was monitored using environmental and biological measurements. The study included 49 salon workers divided by FA levels in the workplace into group A (FA < 0.01 ppm; n = 8), group B (0.03 ppm < FA < 0.06 ppm; n = 15), and group C (0.08 ppm < FA < 0.24 ppm; n = 26). The global DNA methylation levels were 3.12%, 4.55%, and 4.29% for groups A, B, and C, respectively, with statistically higher values for groups B and C compared to group A (p = 0.002). A correlation was found between FA in passive samplers and global DNA methylation (rₛ = 0.307, p = 0.032). Additionally, when only taking into account the hairdressers that performed the BB on clients instead of the whole group, a stronger correlation was observed between FA in personal passive samplers and global DNA methylation (rₛ = 0.764, p = 0.006). For the first time, an increase in DNA methylation was observed in subjects occupationally exposed to FA. In conclusion, our results indicated that even low levels of FA exposure could cause a disturbance in DNA methylation, leading to epigenetic changes, which is associated with cancer development. These data suggest a possible contribution of FA to cancer development through occupational exposure.
اظهر المزيد [+] اقل [-]Virulence-associated traits and in vitro biofilm-forming ability of Escherichia coli isolated from a major river traversing Northern India النص الكامل
2019
Singhal, Neelja | Singh, Nambram Somendro | Maurya, Anay Kumar | Virdi, Jugsharan Singh
Several strains of Escherichia coli harbor virulence traits, resulting in E. coli–related intestinal and extra-intestinal infections. Various studies have reported that extra-intestinal pathogenic E. coli (ExPEC) strains were prevalent in nonhuman reservoirs, including environmental waterways. It is therefore important to identify the pathogenic potential and/or ExPEC status of E. coli strains inhabiting the aquatic environments associated with anthropogenic activities. Besides virulence-associated genes, biofilm production also helps in the survival of E. coli in environmental waterbodies. Thus, the aim of the current study was to assess the virulence potential, ExPEC status, and biofilm-producing capability of E. coli isolated from the River Yamuna, a major river traversing the National Capital Region of Delhi, India. We also tried to discern a co-relation, if any, between virulence, biofilm formation, and antimicrobial resistance in these strains. Our results indicated that virulence-associated genes were scarce and none of the strain qualified the molecular criteria essential for ExPEC. This suggested that E. coli strains which can presumably cause human extra-intestinal infections were not prominent in the River Yamuna. However, the fact that more than 80% of the aquatic E. coli isolates were moderate and strong biofilm producers suggests that E. coli in these environments might serve as opportunistic pathogens. Also, no unequivocal association was observed between biofilm production, virulence, and β-lactamase genes in E. coli strains. As per the best of our knowledge, this is the first study where the relationship between virulence, biofilms, and antimicrobials has been examined in E. coli, isolated from an Indian urban aquatic waterbody.
اظهر المزيد [+] اقل [-]Intradiurnal variation of predominant airborne fungal spore biopollutants in the Central European urban environment النص الكامل
2019
Ščevková, Jana | Hrabovský, Michal | Kováč, Jozef | Rosa, Samuel
Fungal spores are an important cause of allergic respiratory diseases worldwide. However, little is known about the intradiurnal pattern of spore concentrations of different fungal spore types in the air of the urban area. In this study, we evaluated bihourly variation in spore concentration of eight predominant fungal spore types in the atmosphere of Bratislava city (Agrocybe, Alternaria, Cladosporium, Coprinus, Exosporium, Epicoccum, Ganoderma, Leptosphaeria) with the aim to understand the relationships between the spore concentrations against associated environmental variables. Spore samples were collected using a Hirst-type volumetric aerospore trap from January to December 2016. Alternaria, Cladosporium, Epicoccum and Exosporium peaked during the daytime period between 10:00 and 16:00, while for Agrocybe, Ganoderma, Coprinus and Leptosphaeria, the nighttime peaks (20:00 and 04:00) were observed. Effect of a complex of environmental variables on bihourly concentrations of selected airborne fungal spore taxa was evaluated through multiple regression analysis. Air temperature, wind speed, sunshine duration and precipitation were positively associated with daytime spore types, while the association with nighttime spores was negative. In contrast, relative air humidity influenced negatively Exosporium daytime spore type but positively the Leptosphaeria nighttime spore type. Moreover, a circadian cycle of light and darkness was considered as an important predictor of nighttime spore levels. Among the atmospheric pollutants, PM₁₀ was positively associated with all analysed daytime spores, while except for Leptosphaeria, O₃ was negatively associated with nighttime spore types. NO₂ and PM₁₀ had mixed effects on nighttime spore levels. In general, air temperature, PM₁₀ and wind speed were environmental parameters with great influence on airborne fungal spore concentration, being present in eight, seven and four regression models, respectively. Constructed regression models which the best explained variation in fungal spore concentrations were those for Ganoderma (R² = 0.38) and Alternaria (R² = 0.31).
اظهر المزيد [+] اقل [-]Degradation of naproxen in chlorination and UV/chlorine processes: kinetics and degradation products النص الكامل
2019
Liu, Yongze | Tang, Yuqing | Wu, Yongxin | Feng, Li | Zhang, Liqiu
Naproxen (NAP) is a nonsteroidal anti-inflammatory drug which has been widely used and frequently detected in water environments. This study investigated the NAP degradation in the chlorination and UV/chlorine disinfection processes, which usually acted as the last barriers for water treatment. The results showed that both chlorination and UV/chlorine disinfection could remove NAP effectively. At various chlorine dosages (0.1~0.5 mM), the contributions of chlorination and reactive radicals to the degradation of NAP in the UV/chlorine process were calculated to be 50.5~56.9% and 43.1~49.5%, respectively. However, the reactive radicals dominated in NAP degradation in alkaline solutions, while chlorination dominated in acidic conditions. The HCO₃⁻ (10~50 mM) slightly inhibited, Cl⁻ (10~50 mM) gradually promoted, and HA (1~5 mg/L) significantly reduced NAP degradation by UV/chlorine process. The degradation intermediates and products were obtained via high-performance liquid chromatography with QE-MS/MS; NAP was degraded by demethylation, acetylation, and dicarboxylic acid pathways during the chlorination and UV/chlorination processes.
اظهر المزيد [+] اقل [-]Characteristics of vegetable crop cultivation and nutrient releasing with struvite as a slow-release fertilizer النص الكامل
2019
Min, Kyung-Jin | Kim, Daegi | Lee, Jongkeun | Lee, Kwanyong | Park, Ki Young
Struvite precipitation is an effective method to remove and recover ammonia and phosphate from livestock wastewater. Struvite has properties similar to those of the traditional ammonium-phosphate fertilizer, which does not burn the roots owing to its slow-release characteristics. Struvite is an effective fertilizer as its nutrient-releasing rate is very slow. But the release rate of ammonia and phosphate in soil depends on the size of crystals. In this study, the nutrient-releasing pattern of three types of struvite crystals and liquid fertilizer was compared using soil column. X-Ray fluorescence spectrometry was conducted to investigate the potential use of struvite as a fertilizer. Various struvite crystalline fertilizers were evaluated for their fertilizer performance by cultivating potted vegetable crops. The nitrogen removal efficiency of zeolite-seeded struvite was higher than that of no seed struvite. The ammonia nitrogen removal efficiency was more than 99% irrespective of the kind of zeolite. The soil column test revealed that nutrient releasing from liquid fertilizer and zeolite-seeded struvite recovered from livestock wastewater was 11 and 63 days, respectively. Struvite recovered from livestock wastewater contained more than 20% (w/w) potassium oxide; however, the concentration of heavy metals, such as copper and zinc, was very low. Therefore, we considered that the synthesized struvite using livestock wastewater has high value as fertilizer. The recovered struvite was effective under appropriate concentrations to cultivate all the applied vegetable crops in this study.
اظهر المزيد [+] اقل [-]Toxicity of the aquatic herbicide, reward®, to the northwestern salamander النص الكامل
2019
Moreton, Michael L. | Marlatt, Vicki L.
Diquat dibromide (DB) is the active ingredient in several herbicide products used around the world for industrial and recreational control of terrestrial and aquatic pest plants. This study aimed to assess the adverse effects of the commercial formulation of the aquatic herbicide, Reward®, on the Pacific Northwest amphibian species, the northwestern salamander (Ambystoma gracile). Larvae were exposed to the Reward® herbicide in a 96-h acute bioassay (0.37–151.7 mg/L DB) and a continuous 21-day exposure (0.37–94.7 mg/L DB). The 96-h LC₅₀ was 71.5 mg/L and the 21-day LC₅₀ was 1.56 mg/L. Collectively, the results of this study demonstrate that early life stage A. gracile larvae appear largely insensitive to acute Reward® exposures compared to early life stage fish. However, A. gracile larvae are considerably more sensitive during sub-chronic exposure (21 days) with lethal and sub-lethal effects on growth occurring in the 1–2 mg/L range, which more closely resembles the larval fish lethal sensitivity to this active ingredient. This is the first study examining the toxicity of the aquatic herbicide formulation Reward® on A. gracile under acute and sub-chronic exposure scenarios.
اظهر المزيد [+] اقل [-]Enhanced adsorption of Cd (II) from aqueous solution by a shrimp bran modified Typha orientalis biochar النص الكامل
2019
Yin, Wenjun | Zhao, Congcong | Xu, Jingtao
The biochar which was characterized with well-developed facial structure and O-/N-containing functional groups could effectively remove Cd (II) from water. In this paper, Typha orientalis–based biochar (BCS) with well-developed N containing functional groups was modified with shrimp bran which was rich in crude protein for the first time. There are more well-developed O-/N-containing functional groups in the structure of BCS than that of pure Typha orientalis–based biochar without any modification (BC), and this conclusion was depended on their comparisons of Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), scanning electron microscopy (SEM), elemental analysis (EA), Boehm titration, Fourier transform infrared (FTIR), and other characterization techniques. Moreover, according to the experiment, the phenomenon that the adsorption capacity of Cd(II) on these two adsorbents (BCs) decreased with the increase of solution ionic strength could be carried out. The Cd(II) adsorption studies combined with X-ray photoelectron spectroscopy (XPS) analysis revealed that the adsorption mechanism was mainly attributed to physical microporous filtration and chemical interaction between Cd(II) and the surface functional groups (surface complexation, ion exchange, and electrostatic attraction).
اظهر المزيد [+] اقل [-]Effects of fiscal decentralisation on the environment: new evidence from China النص الكامل
2019
Liu, Liangliang | Li, Linmu
The aim of this paper is to explore the environmental effects of fiscal decentralisation from theoretical and empirical perspectives. We first analyse the dynamic relationship between fiscal decentralisation and the environment using an endogenous growth model. Our findings demonstrate that fiscal decentralisation and environmental pollution display an inverted U-shaped relationship. We then use provincial panel data from 1998 to 2015 in the empirical investigation of CO₂ emissions in China. Our findings show that empirical results verify the correctness of the theoretical results. The results obtained are robust using different methods. The findings of this work may help China’s central government and local governments in addressing the problem of CO₂ emissions by using a reasonable degree of fiscal decentralisation.
اظهر المزيد [+] اقل [-]Performance of Aeluropus lagopoides (mangrove grass) ecotypes, a potential turfgrass, under high saline conditions النص الكامل
2019
Zamin, Muhammad | Khattak, Abdul Mateen | Salim, Abdul Mohsin | Marcum, Kenneth B. | Shakūr, Muḥammad | Shah, Shahen | Jan, Ibadullah | Shah, Fahad
Climate change has become a real threat, and its impacts are being felt throughout the world. Temperature is considered one of the significant elements by the recent consequences of climate change and global warming, specially the salinity which is increased at higher temperature. Turfgrasses are adversely affected due to an increasing trend in salinity. The main aim of this investigation was to find out salt-tolerant ecotypes from native species of UAE to mitigate the salinity problem. Performance of a native grass, Aeluropus lagopoides, was investigated under high saline conditions during the year 2014 under the UAE climatic conditions. The experiment was planned under randomised complete block design (RCBD) with two factors and four replications. During the experiment, 50 ecotypes of Aeluropus lagopoides, alongside Paspalum vaginatum (as control), were tested at different salt levels, i.e. 0, 15, 30, 45, 60 and 75 dSm⁻¹. Significant differences were found among various ecotypes as well as salinity levels for different agronomic traits including green cover, canopy stiffness, leaf colour and salinity of leaf rinseates. Most of the ecotypes tolerated salinity up to 30 dSm⁻¹, maintaining the quality, but beyond this level the quality declined. However, some of the ecotypes survived under high salinity, even beyond sea level (75 dSm⁻¹). All the ecotypes, except RUA2, RUA3 and RUA1, showed better performance than P. vaginatum, the prevailing commercial turfgrass in the UAE. Based on their performance, the ecotypes RUDA7, FA5, RA3, RUDA2 and RA2 could be used for turf purposes under saline conditions.
اظهر المزيد [+] اقل [-]Dynamics of the remediating effects of plant litter on the biological and chemical properties of petroleum-contaminated soil النص الكامل
2019
Zhang, Xiaoxi | Zhou, Wenxing | Liu, Hui | Bai, Erlei | Zhang, Jizhou | Liu, Zengwen
To investigate the comprehensive remediating effects of plant residues on biological and chemical properties and the long-term dynamics of these effects, litter from Caragana korshinskii (caragana) or Ziziphus jujuba var. spinosa (jujube) was mixed with three types of soil that were contaminated with 12.49, 27.54, and 45.37 g kg⁻¹ of petroleum. The mixtures were incubated at 20–25 °C with consistent soil moisture for 360 days. Subsequently, the litter impacts on the soil microbial population, the activities of 12 types of soil hydrolytic, and redox enzymes related to the cycling of C, N, and P, and the available N, P, and K contents were determined during the incubation. The results indicated that both types of litter significantly accelerated the reproduction of soil microbes and significantly increased the activities of most of the hydrolytic enzymes and the available nutrient contents after the short-term treatments, while the litters usually simultaneously depressed the activities of polyphenol oxidase and peroxidase in the slightly and moderately contaminated soils. However, the comprehensive remediating effects of the litters on the lightly contaminated soil significantly decreased over time while it recovered to some extent at the end of the experiment. The remediating effects on the seriously contaminated soil exhibited the opposite trend, and their remediating effects on the moderately contaminated soil exhibited continuous weakening. Generally, the remediating effects of the caragana litter were more noticeable than those of the jujube litter, except for the effect on the slightly contaminated soil after 180 days of treatment.
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