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Результаты 6171-6180 из 6,546
Modification of epoxy groups of poly(hydroxylmethyl methacrylate-co-glycidyl methacrylate) cryogel with H3PO4 as adsorbent for removal of hazardous pollutants Полный текст
2020
Bayramoglu, Gulay | Arica, Mehmet Yakup
Poly(hydroxylmethyl methacrylate-co-glycidyl methacrylate) (p(HEMA-GMA)) macroporous cryogel with high density of epoxy groups was synthesized, and the epoxy groups of the cryogel were modified into phosphonate groups. The effects of dye concentrations, adsorption time, pH, salt concentration, and adsorption temperature on the adsorption of Direct Blue-53 (DB-53) and Reactive Blue-160 (RB-160) dyes were studied. The maximum adsorption capacity was found to be 245.3 and 155.8 mg/g (0.255 or 0.119 mmol/g) for the DB-53 and RB-160 dyes, respectively. The higher adsorption capacity achieved for the DB-53 compared with the RB-160 dye can result from the pendant primary amino groups of the DB-53 dye as well as the smaller size of the dye molecule. The Langmuir isotherm model and the pseudo-second-order kinetic model well described the experimental data. The p(HEMA-GMA)-PO₄²⁻ adsorbent has many operational advantages for the removal of pollutants. It could be a promising adsorbent to be used in industrial wastewater treatment.
Показать больше [+] Меньше [-]Incidence of morphometry variation, growth alteration, and reproduction performance of the annular sea bream (Diplodus annularis) as effective tools to assess marine contamination: how useful is a multi-biotimarkers approach? Полный текст
2020
Gharred, Tahar | Mannai, Rabeb | Belgacem, Mariem | Jebali, Jamel
A wide variety of contaminants in the aquatic environment causes several deleterious effects on aquatic organism traits ranging from molecular to individual and population levels. This in situ study investigated morphometry, growth performance, and reproduction success of a teleost fish, Diplodus annularis, from a polluted site “Sayada” and a reference site “Salakta” in the eastern Tunisian coastline. Morphometric indexes, generalized Procruste analysis, thin plate, and otolith contour methods were used to assess the pollution effects on morphological traits. The growth performance of fish from contaminated and control sites were studied using the Von Bertalanffy equation. Gonadosomatic (GSI) and Hepatosomatic (HSI) Indexes and absolute and relative fecundity were used to assess the impact of pollution on the reproduction success of this species. The obtained results showed that the fish of the contaminated zone had significant alteration of the morphology, slower growth, significant increase in the HSI, significant decrease in female GSI, and a decrease in absolute and relative fecundity compared to specimens from the unpolluted zone. Based on these results, the biological traits of Diplodus annularis can be used as biological biomarkers in the monitoring and protection programs of the marine contamination in the Mediterranean Sea.
Показать больше [+] Меньше [-]Anthracene-induced DNA damage and oxidative stress: a combined study at molecular and cellular levels Полный текст
2020
Sun, Kailun | Song, Yan | Zong, Wansong | Tang, Jingchun | Liu, Rutao
At present, research progress of anthracene’s toxicity lags far behind the pollution caused on its application fields such as petroleum and minerals. In this paper, anthracene-induced oxidative stress effects and genetic toxicity were investigated at both the molecular and cellular levels. The intracellular oxidative stress effect of anthracene on earthworm primary coelomocyte was confirmed by the detection of reactive oxygen species, antioxidant enzymes activity, and malondialdehyde content. Moreover, after anthracene exposure, the decrease in the mitochondrial membrane potential and cell viability also indicated the adverse effects of anthracene on earthworm coelomocyte. The comet assay proved the break in DNA strand, revealing the anthracene-induced DNA damage. On the molecular level, we revealed that anthracene caused the shrinkage of the catalase skeleton and altered the microenvironment of chromophores of catalase by multi-spectral methods. Molecular simulation results indicated that anthracene interacted with His74 by “arene-arene” force and the dominant binding site between anthracene and catalase was close to the active site of catalase. In addition, anthracene was shown to bind to the DNA molecule by groove binding mode. This study proposed a new combined analysis method for the toxicity evaluation of anthracene at the cellular and molecular levels. Graphical abstract This study creatively proposed a new combined analysis for the toxicity evaluation of ANT at the cellular and molecular levels.
Показать больше [+] Меньше [-]Retention of nitrogen and phosphorus in Lake Chaohu, China: implications for eutrophication management Полный текст
2020
Wang, Yanping | Kong, Xiangzhen | Peng, Zhaoliang | Zhang, Hui | Liu, Gang | Hu, Weiping | Zhou, Xiangqian
Nutrient retention is an important process in lake nutrient cycling of lakes and can mitigate lake eutrophication. However, little is known about temporal lake nutrient retention efficiency and it varies due to changes in hydrological, ecological, and nutrient inputs to lake waters. Quantitative information about seasonal lake N and P retention is critical for developing strategies to reduce eutrophication in lake systems. This study investigated TN and TP retention efficiencies and retention masses using water and mass balance calculations, and statistically analyzed the seasonal variability of nutrient retention in Lake Chaohu, China, from 2014 to 2018. Lake Chaohu experienced large amounts of external loads inputs (23.2 g N m⁻² year⁻¹ and 1.3 g P m⁻² year⁻¹), and approximately 58% TN and 48% TP were retained annually. The lake acted more as a sink for N than for P. The mean annual TP retention efficiency decreased (P < 0.05) over the study period, indicating that TP retention capacity was gradually exceeded. Seasonal variability of TN and TP retention efficiency was high and ranged from − 18.7 to 144.1% and from − 58.8 to 170.7%, respectively, over the five study years. The internal P loads over the study period were equivalent to roughly 9% of the total external loads. The annual nutrient retention efficiency of TN and TP increased with hydraulic residence time, while water temperature was an essential factor for the contrasting seasonal variation patterns of TN and TP retention efficiencies.
Показать больше [+] Меньше [-]Mechanisms and pathogenesis underlying environmental chemical-induced necroptosis Полный текст
2020
Sepand, Mohammad-Reza | Aliomrani, Mehdi | Hasani-Nourian, Yazdan | Khalhori, Mohammad-Reza | Farzaei, Mohammad-Hosein | Sanadgol, Nima
Necroptosis is a regulated cell death that is governed by mixed lineage kinase domain-like, receptor-interacting serine-threonine kinase 3 and commonly displays with necrosis morphological characteristics. This study examined the molecular mechanisms involved in the chemical-induced necroptosis where a systematic evaluation of experimental studies addressing this issue is missing. We strictly reviewed all scientific reports related to our search terms including “necroptosis” or “programmed necrosis”, “environmental chemicals” or “air pollutants” or “pesticides” or “nanoparticles” and “Medicines” from 2009 to 2019. Manuscripts that met the objective of this study were included for further evaluations. Studies showed that several pathological contexts like cancer, neurodegenerative disorders, and inflammatory diseases were related to necroptosis. Furthermore, multiple chemical-induced cytotoxic effects, such as DNA damage, mitochondrial dysregulation, oxidative damage, lipid peroxidation, endoplasmic reticulum disruption, and inflammation are also associated with necroptosis. The main environmental exposures that are related to necroptosis are air pollutants (airborne particulate matter, cadmium, and hydrogen sulfide), nanoparticles (gold, silver, and silica), pesticides (endosulfan, cypermethrin, chlorpyrifos, and paraquat), and tobacco smoke. To sum up, air pollutants, pesticides, and nanoparticles could potentially affect human health via disruption of cell growth and induction of necroptosis. Understanding the exact molecular pathogenesis of these environmental chemicals needs further comprehensive research to provide innovative concepts for the prevention approaches and introduce novel targets for the amelioration of a range of human health problems.
Показать больше [+] Меньше [-]Examining foreign direct investment and environmental pollution linkage in Asia Полный текст
2020
Khan, Muhammad Azam | Ozturk, Ilhan
This study investigated the causal linkage between environmental pollution by carbon dioxide (CO₂) emissions and net foreign direct investment (FDI), along with some other variables, namely economic growth by real per capita income and trade openness, using balanced annual data of 17 countries from Asia for the period from 1980 to 2014. Panel cointegration tests confirm the long-run association among the variables. After checking the panel data for stationarity properties, the method panel fully modified ordinary least squares (FMOLS) is implemented. The FMOLS estimates on CO₂ emission model reveal that inward FDI has a significantly positive impact on environmental pollution, supporting the pollution haven hypothesis (PHH). Likewise, FDI model results imply that CO₂ emissions represent environmental pollution; economic growth and trade openness are the pivotal determinants of FDI. Panel causality results suggest bidirectional linkages between CO₂ emissions and inward FDI. Empirical findings suggest that economic policy reforms are required to channelise foreign capital inflows to a more environmentally healthy direction. The governments of Asian countries should chalk out policies on FDI inflows and the environment in order to achieve sustainable economic growth and development.
Показать больше [+] Меньше [-]Radiolytic degradation of chlorobenzene in aerated and deoxygenated aqueous solutions Полный текст
2020
Albarrán, Guadalupe | Mendoza, Edith
Radiation-induced degradation of chlorobenzene was conducted at 0.1, 0.4, 0.5, 0.7, and 1.0 mmol/dm³ concentrations in aerated environment and at 1.0 mmol/dm³ in oxygen-free and N₂O-saturated solutions. The results demonstrated that the elimination of chloride is important when the solution is oxygen free, because the [Formula: see text] attacks at the ipso position of the chloro group produces hydrochloric acid. The degradation was affected to a large extent by the concentration and to a lesser extent by the presence or absence of oxygen in the solutions which were irradiated. Thereby, the degradation occurred faster in the solutions with air and without oxygen and more slowly in the saturated solution with N₂O. Some by-products were identified using an HPLC-UV-mass system. In addition, it was found that there is a linear correlation between the ln C/C₀ and the dose, indicating that the radiolytic degradation followed pseudo-first-order reaction kinetics. The radiolytic oxidation was followed by the chemical oxygen demand (COD) test. The COD decreases when the solute concentration increases. The COD results were for a 0.47 mmol/dm³ of 5.94 mg O₂ dm⁻³ kGy⁻¹ and for 0.09 mmol/dm³ of 7.45 mg O₂ dm⁻³ kGy⁻¹.
Показать больше [+] Меньше [-]The effect of finance on inequality in Sub-Saharan Africa: avoidable CO2 emissions thresholds Полный текст
2020
Asongu, Simplice A. | Vo, Xuan V.
There is a glaring concern of income inequality in the light of the post-2015 global development agenda of Sustainable Development Goals (SDGs), especially for countries that are in the south of the Sahara. There are also concerns over the present and future consequences of ecological degradation on development outcomes in Sub-Saharan Africa (SSA). This study provides carbon dioxide (CO₂) emissions thresholds that should be avoided in the nexus between financial development and income inequality in a panel of 39 countries in SSA over the period 2004–2014. Quantile regressions are used as an empirical strategy. The following findings are established. Financial development unconditionally decreases income inequality with an increasing negative magnitude, while the interactions between financial development and CO₂ emissions have the opposite effect with an increasing positive magnitude. The underlying nexuses are significant exclusively in the median and top quantiles of the income inequality distribution. CO₂ emission thresholds that should not be exceeded for financial development to reduce income inequality continuously are 0.222, 0.200, and 0.166 (metric tons per capita) for the median, the 75th quantile, and the 90th quantile of the income inequality distribution, respectively. Policy implications are discussed with particular relevance to Sustainable Development Goals (SDGs).
Показать больше [+] Меньше [-]A multidiversity approach to investigate the impact of mining exploitation on spider diversity in the abandoned mine district of Montevecchio-Ingurtosu (Sardinia, Italy) Полный текст
2020
Mannu, Roberto | Pantini, Paolo | Sassu, Antonio | Verdinelli, Marcello
The impact of mining activities on spider (Araneae) diversity and assemblages was studied in two abandoned mine sites in Sardinia (Italy), where mining activities started in the middle of the nineteenth century and closed down over a century later. Spider community composition was analysed in dumps, undisturbed forests and scrublands which represent the natural chronosequence following the abandonment of the mining district. The identification of spiders was performed at the lowest taxonomic level possible and differences in abundance, species richness (SR), and functional diversity (FD) were analysed. Nonmetric multidimensional scaling (NMDS) and a permutated multivariate analysis of variance (PERMANOVA) routine were conducted to evaluate the relationships of spider assemblages with land cover, and the indicator species analysis was performed to identify the typifying species. During the entire sampling period, 2312 spiders were captured, and approximately 80% of the total were identified at the species level (79 spider species belonging to 28 different families). No differences in abundance and SR were found, whereas FD, which showed the highest values in forests, significantly differed among sites. A distinct separation among assemblages and a significant effect of the land use on spider assemblages were found (PERMANOVA, R² = 0.59, p < 0.001). Twelve species were selected as indicator species. Our results underlined the possibility to consider ground-dwelling spiders as a valuable target group for biomonitoring programmes supporting projects of near-natural restoration and/or technical reclamation of mining sites.
Показать больше [+] Меньше [-]CYP1A1 and GSTs common gene variations and presbycusis risk: a genetic association analysis and a bioinformatics approach Полный текст
2020
Karimian, Mohammad | Behjati, Mohaddeseh | Barati, Erfaneh | Ehteram, Tayyebeh | Karīmiyān, ʻAlī
Antioxidant enzymes such as glutathione S-transferases (GSTs) and cytochromes P450 (CYPs) are involved in the metabolism and detoxification of cytotoxic compounds, as well as the elimination of reactive oxygen species (ROS). Therefore, alterations in the structure of these enzymes could result in prolonged production of ROS with subsequent risk of development of disorders such as presbycusis. This study aimed to investigate the association between CYP1A1 (rs4646903, rs1048943) and GSTs (GSTM1-deletion, GSTT1-deletion, GSTP1-rs1695) with presbycusis risk in an Iranian population which was followed by an in silico approach. In a case-control study, 280 subjects including 140 cases with presbycusis and 140 healthy controls were enrolled. Genotypes of single-nucleotide polymorphisms (SNPs) were detected by PCR-RFLP method and the genotype of the above mentioned deletions was determined by touchdown PCR. Some bioinformatics tools were employed to evaluate the impact of SNPs on the gene function. SNP analysis revealed that there are significant associations between rs1048943 (AG vs. AA: OR = 2.46, 95%CI = 1.30–4.65, p = 0.006; GG + AG vs. AA: OR = 2.53, 95%CI = 1.36–4.69, p = 0.003; G vs. A: OR = 2.36, 95%CI = 1.33–4.17, p = 0.003) and rs4646903 (C vs. T: OR = 1.45, 95%CI = 1.02–2.06, p = 0.040) variations and increased risk of presbycusis. However, there was no significant association between rs1695 and presbycusis risk. Also, significant associations were observed between GSTM1 (OR = 4.28, 95%CI = 1.18–15.52, p = 0.027) and GSTT1 (OR = 1.64, 95%CI = 1.02–2.65, p = 0.041) deletions and elevated risk of presbycusis. Moreover, the combination analysis revealed a significant association between GSTM1+/GSTT1− genotype and presbycusis susceptibility (OR = 1.63, 95%CI = 1.00–2.67, p = 0.049). In silico analysis revealed that the rs1048943 SNP could influence significantly on the RNA structure of CYP1A1 (distance: 0.1454; p value: 0.1799). Based on our findings, the rs4646903, rs1048943 SNPs as well as GSTM1 and GSTT1 deletions could be considered as genetic risk factors for the development and progression of presbycusis.
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