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Inter-comparison of carbon content in PM10 and PM2.5 measured with two thermo-optical protocols on samples collected in a Mediterranean site 全文
2019
Merico, Eva | Cesari, Daniela | Dinoi, Adelaide | Gambaro, Andrea | Barbaro, Elena | Guascito, Maria R. | Giannossa, Lorena C. | Mangone, Annarosa | Contini, Daniele
Scientific interest is focusing on different approaches for characterising organic carbon (OC), elemental carbon (EC) and equivalent black carbon (eBC), although EUSAAR2 protocol has been established and frequently used in EU for regulatory purposes. Discrepancies are observed due to thermal protocols used for OC/EC determinations and the effect of the chemical-physical properties of aerosol using optical measurements for eBC. In this work, a long-term inter-comparison of carbon measurements with two widely used protocols (EUSAAR2 and NIOSH870) was performed on PM₂.₅ and PM₁₀ samples. The influence of the protocol on the evaluation of secondary organic aerosol (SOC) and on the correlation between EC and eBC was investigated. An extensive check of repeatability gave typical uncertainties of ~ 5% for TC and OC, and ~ 10% for EC for both thermal protocols. Results show that OC is statistically comparable between the two protocols but EC is significantly higher with EUSAAR2, especially during the warm season. The ratio OC/EC is lower with EUSAAR2, also showing a seasonality (lower values in the warm season) not observed with NIOSH870. Despite the differences in OC/EC ratios, the contribution of SOC to OC (~ 50%), evaluated using the EC-tracer method, did not differ significantly between the two protocols and for both size fractions. Further, SOC/OC ratios were comparable in cold and warm periods. eBC/EC ratios larger than one for both protocols were obtained, 1.62 (EUSAAR2) and 1.92 (NIOSH870), and also correlated with the ratio OC/EC for both protocols, especially in the cold season.
显示更多 [+] 显示较少 [-]Diversity in flower colorations of Ranunculus asiaticus L. revealed by anthocyanin biosynthesis pathway in view of gene composition, gene expression patterns, and color phenotype 全文
2019
Liu, Yanfang | Zhang, Jianhua | Yang, Xiaohong | Wang, Jiangmin | Li, Yangang | Zhang, Peng | Mao, Jin | Huang, Qingmei | Tang, Hao
Anthocyanin biosynthesis is one of the best studied secondary metabolisms. However, related pathways were generally concluded based on anthocyanin components; most studies focused on the backbone forming of anthocyanidins (cyanidin, delphinidin, and pelargonidin) of model or commercial plants, while anthocyanin modification was less discussed, and non-model plants with abundant colorations were less researched either. Ranunculus asiaticus L. has great diversity in flower colorations, not only indicating its value in researching anthocyanin biosynthesis but also implying it is unique in this regard. Based on transcriptome sequencing and gene annotation of three varieties (10 samples) of Ranunculus asiaticus L., 176 unigenes from 151,136 unigenes were identified as involved in anthocyanin biosynthesis, among which, 74 unigenes were related to anthocyanin modification; 61 unigenes were responsible for glycosylation at C3 and C5 with 3-monosaccharides of glucose, 3-biosides of rutinose, sophorose, or sambubiose to form 3Gly-, 3Gly5Gly-, 3Gly3′Gly-, 3Gly2′′Gly-, 3Gly2′′Xly-, 3Gly2′′Rly-glycosylated anthocyanins, etc.; 2 unigenes transferred –CH₃; 11 unigenes of BAHD family catalyzd the aromatic or malonyl acylation at 6′′ / 6′′′′position of 3/5-O-glucoside. Based on gene composition, a putative pathway was established. The pathway was validated by flower colorations, and gene expression patterns where F3H, F3′H, 3GT, 5GT, and FMT2 were highly expressed in varieties colored as lateritious and carmine, while variety with purple flowers had high expression of F3′5′H and 3MAT. In view of anthocyanin biosynthesis pathway of Ranunculus asiaticus L., great diversity in its flower colorations was illustrated via the complete branches (F3H, F3′H and F3′5′H) as well as complete modifications (glycosylation, methylation, and acylation), and besides, via the higher percentage of C3 glycosylation than C5 glycosylation.
显示更多 [+] 显示较少 [-]Diversity of tetracycline- and erythromycin-resistant bacteria in aerosols and manures from four types of animal farms in China 全文
2019
Chen, Mo | Qiu, Tianlei | Sun, Yanmei | Song, Yuan | Wang, Xuming | Gao, Min
Confined animal feeding operations generate high levels of airborne antibiotic-resistant bacteria, including pathogenic strains that may pollute the local environment or pose a health risk to both animals and workers. However, the communities of airborne antibiotic-resistant bacteria in such operations are not fully understood, especially in fine particles that penetrate deeply into the respiratory system. To address these gaps, manures and aerosols from inside and outside of animal houses were collected, and the characteristics of antibiotic-resistant bacteria were analyzed using Illumina MiSeq sequencing to amplify the V3–V4 region of bacterial 16S rRNA. The results indicated that animal species was the main factor that influenced the bacterial community of both manure and aerosol samples, while antibiotic selection was the major factor that influenced the bacterial community of aerosol samples from the inside of animal houses. An obvious clustering difference was detected between manure and aerosol samples. No significant difference in both alpha- and beta-diversity indices was detected between fine and coarse particles. As a key genus, Staphylococcus was found to drive the difference in the bacterial community of tetracycline-resistant bacteria to total culturable bacteria and erythromycin-resistant bacteria and also the difference in the bacterial community from aerosol to manure samples. Current data would help in evaluating the risk to human and livestock health and tracing the source of airborne antibiotic-resistant bacteria in animal farms.
显示更多 [+] 显示较少 [-]Reclamation suitability evaluation of damaged mined land based on the integrated index method and the difference-product method 全文
2019
Cheng, Linlin | Sun, Haiyuan
Reclamation suitability evaluation is the basis for determining the reuse direction of damaged land. Most scholars’ studies have focused on the improvement and innovation of evaluation models and methods, while the analysis of restrictive factors is rarely involved. This paper evaluates the reclamation suitability of damaged land around Longchi coal mine by the integrated index method and the analysis of restrictive factors is carried out by the difference-product method. The result shows damaged land around the Longchi coal mine is most suitable for being reclaimed as woodland. The main restrictive factors are the degree of contamination of the soil and water and the irrigation conditions. This study provides a basis for the rational reutilization and improvement options of damaged land around Long Chi coal mine. The study also verifies that the combination of the integrated index method and the difference-product method work well for evaluating reclamation suitability and for analyzing restrictive factors in case of no prominent evaluation indexes.
显示更多 [+] 显示较少 [-]Study on shear behavior of kaolinite contaminated by heavy metal Cu (II) 全文
2019
Zhang, Zhihong | Chen, Yang | Fang, Jianghua | Guo, Fei
Numerous studies have shown that the invasion of the chemicals plays an important role on the geomechanical properties of the soil. This article aims to investigate the shear behavior of contaminated soil by laboratory tests and develop an extended shear strength model on the basis of the experimental results. In order to explicitly evaluate the effect of solution concentration on the shear strength behavior of soil, the remolded samples of kaolinite mixed with different concentrations of CuCl₂ solutions were prepared to carry out a series of consolidated-undrained triaxial shear strength tests. The results indicate that different CuCl₂ solution concentrations have significant influence on the shear strength property of kaolinite. With the increase of CuCl₂ solution concentration, the shear strength of soil displays a declining tendency, and the strength properties including cohesion and internal friction angle are also reduced, which indicates the Cu (II) that existed in the soil samples has deteriorated the soil strength strongly. Based on the experimental results, an extended Mohr–Coulomb strength model for contaminated soils has been proposed by introducing osmotic suction as a macro variable parameter. The conclusions in this study can provide reference for pollution prevention of existing and future foundations.
显示更多 [+] 显示较少 [-]Effects of typical modified passivators on speciation of heavy metals in protein extracted from sewage sludge 全文
2019
Wang, Weiyun | Zhang, Jin | Li, Xueshen | Zang, Ying | Li, Rundong
The sewage sludge contains abundant organic substances as well as a complex variety of inorganic substances (such as heavy metals). The extraction of protein from sludge is a new treatment approach to promote the utilization of sludge as a resource. However, heavy metals in sludge are extracted together with organic matter during the extraction process. In this study, the amounts of protein and heavy metal in the supernatant extracted from sewage sludge were investigated, and the effects of different passivator (modified fly ash and modified sepiolite) on the speciation of different heavy metals in the sludge were examined. Both materials reduced the contents of protein and heavy metal in the supernatant. When the dosage of sepiolite was 0.10 g/g total suspended solids of sludge, the content of heavy metals was the lowest and the protein content had little change. It can be deduced by analysis of specific area that sepiolite can complex with heavy metal ions and the fly ash adsorb the metals by physical adsorption. The modified sepiolite can be seen as an ideal passivator due to higher protein content and less heavy metals in the supernatant, as well as more stable heavy metals in the sediments.
显示更多 [+] 显示较少 [-]Influence of CaO-activated silicon-based slag amendment on the growth and heavy metal uptake of vetiver grass (Vetiveria zizanioides) grown in multi-metal-contaminated soils 全文
2019
Mu, Jing | Hu, Zhengyi | Xie, Zijian | Huang, Lijuan | Holm, Peter E.
Few plant species used for revegetation grow well in multi-metal-contaminated soils. Vetiver grass (Vetiveria zizanioides) is known to be tolerant of heavy metals. Vetiver has been reported to be effective for revegetation and heavy metal phytoextraction by applying targeted amendments due to its large biomass. In this study, a greenhouse vetiver pot experiment and soil incubation were performed to investigate the growth and Cd, Cr, Cu, Pb, and Zn uptake of vetiver grown in multi-metal-contaminated soils treated with a CaO-activated Si-based slag amendment (0, 0.5, 1.0, and 2.0% w/w). The results showed that the effects of slag amendment on plant growth and heavy metal uptake and distribution were dependent on the amendment dosages and metal species. Although vetiver could grow in contaminated soils, its growth was obviously inhibited. The slag amendment enhanced the vetiver growth and the highest biomass (2.62-fold over the control) was determined at a 1.0% amendment rate. The slag amendment improved plant growth by alleviating the toxicity of heavy metals in plants. This result was mainly attributed to the increases in soil pH and citric acid-extractable Si caused by alkaline amendment. The results suggest that vetiver can be applied to remediate multi-metal-contaminated soils in conjunction with the application of CaO-activated Si-based slag amendment.
显示更多 [+] 显示较少 [-]Estimating the role of climate changes on international tourist flows: evidence from Mediterranean Island States 全文
2019
Katircioglu, Setareh | Cizreliogullari, Mehmet Necati | Katircioglu, Salih
This article examines the role of climate change on tourist flows to Malta, Cyprus (north), and Cyprus (south) which are major tourist destinations in the Mediterranean. Results from time series analyses reveal that climate change positively impacts on foreign tourist flows to these island states. Thus, this finding is reasonable where we argue that global warming leads to increases in international tourist arrivals to small island states. This paper has also found statistically significant effects of overall energy consumption on foreign tourist arrivals to Malta and Cyprus revealing that energy efficiency policies are essential in small island states.
显示更多 [+] 显示较少 [-]Modified CDKN2B (p15) and CDKN2A (p16) DNA methylation profiles in urban pesticide applicators 全文
2019
Herrera-Moreno, José Francisco | Medina-Díaz, Irma Martha | Bernal-Hernández, Yael Yvette | Ramos, Kenneth S. | Alvarado-Cruz, Isabel | Quintanilla-Vega, Betzabet | González-Arias, Cyndia Azucena | Barrón-Vivanco, Briscia Socorro | Rojas-García, Aurora Elizabeth
Gene-specific changes in DNA methylation by pesticides in occupationally exposed populations have not been studied extensively. Of particular concern are changes in the methylation profile of tumor-suppressor, such as CDKN2B and CDKN2A, genes involved in oncogenesis. The aim of this study was to evaluate the methylation profiles of CDKN2B and CDKN2A genes in urban pesticide applicators and their relationship with occupational exposure to pesticides. A cross-sectional study was conducted in 186 urban pesticide applicators (categorized as high or moderate exposures) and 102 participants without documented occupational exposures to pesticides. Acute and chronic pesticide exposures were evaluated by direct measurement of urinary dialkylphosphates, organophosphate metabolites, and a structured questionnaire, respectively. Anthropometric characteristics, diet, clinical histories, and other variables were estimated through a validated self-reported survey. DNA methylation was determined by pyrosequencing of bisulfite-treated DNA. Decreased DNA methylation of the CDKN2B gene was observed in pesticide-exposed groups compared to the non-exposed group. In addition, increased methylation of the CDKN2A promoter was observed in the moderate-exposure group compared to the non-exposed group. Bivariate analysis showed an association between CDKN2B methylation and pesticide exposure, general characteristics, smoking status, and micronutrients, while changes in CDKN2A methylation were associated with pesticide exposure, sex, educational level, body mass index, smoking status, supplement intake, clinical parameters, and caffeine consumption. These data suggest that pesticide exposure modifies the methylation pattern of CDKN2B and CDKN2A genes and raise important questions about the role that these changes may play in the regulation of cell cycle activities, senescence, and aging.
显示更多 [+] 显示较少 [-]Correction to: Study on habitat suitability of overwintering cranes based on landscape pattern change—a case study of typical lake wetlands in the middle and lower reaches of the Yangtze River 全文
2019
Cui, Yanglin | Dong, Bin | Chen, Lingna | Gao, Xiang | Cui, Yuhuan
The correct corresponding Author of this paper is Bin Dong.
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