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Gene expression in snapbeans exposed to ozone and protected by ethylenediurea Full text
2014
Paoletti, E. | Castagna, A. | Ederli, L. | Pasqualini, S. | Ranieri, A. | Manning, W.J.
Ethylenediurea (EDU) is the most common chemical used to prevent ozone (O3) injury on vegetation. Despite considerable research, its mode of action remains elusive and gene expression has not been studied. Transcripts of major antioxidant enzymes (catalase, glutathione reductase, glutathione peroxidase) were measured for the first time in a model plant (Phaseolus vulgaris cv S156) after short-term O3 exposure (0 or 90 ppb, 5 h/d, 4 days) and a single spray with EDU (0 or 300 ppm). Visible, physiological and biochemical parameters were assessed as indices of O3-induced stress. In O3-exposed EDU-protected plants, levels of transcript, enzyme activity, H2O2 accumulation, gas exchange and foliar visible injury were similar to those in control plants. These results suggest that EDU may halt the O3-induced ROS generation within 24 h from the exposure, and thus the downstream cascade mechanisms leading to increased H2O2 production, impaired gas exchange, and occurrence of leaf lesions.
Show more [+] Less [-]Role of sectoral and multi-pollutant emission control strategies in improving atmospheric visibility in the Yangtze River Delta, China Full text
2014
Huang, Kan | Fu, Joshua S. | Gao, Yang | Dong, Xinyi | Zhuang, Guoshun | Lin, Yanfen
The Community Multi-scale Air Quality modeling system is used to investigate the response of atmospheric visibility to the emission reduction from different sectors (i.e. industries, traffic and power plants) in the Yangtze River Delta, China. Visibility improvement from exclusive reduction of NOx or VOC emission was most inefficient. Sulfate and organic aerosol would rebound if NOx emission was exclusively reduced from any emission sector. The most efficient way to improve the atmospheric visibility was proven to be the multi-pollutant control strategies. Simultaneous emission reductions (20–50%) on NOx, VOC and PM from the industrial and mobile sectors could result in 0.3–1.0 km visibility improvement. And the emission controls on both NOx (85%) and SO2 (90%) from power plants gained the largest visibility improvement of up to 4.0 km among all the scenarios. The seasonal visibility improvement subject to emission controls was higher in summer while lower in the other seasons.
Show more [+] Less [-]Interrogating trees for isotopic archives of atmospheric sulphur deposition and comparison to speleothem records Full text
2014
Wynn, P.M. | Loader, N.J. | Fairchild, I.J.
Palaeorecords which depict changes in sulphur dynamics form an invaluable resource for recording atmospheric pollution. Tree rings constitute an archive that are ubiquitously available and can be absolutely dated, providing the potential to explore local- to regional-scale trends in sulphur availability. Rapid isotopic analysis by a novel “on-line” method using elemental analyser isotope ratio mass spectrometry (EA-IRMS) is developed, achieving sample precision of <0.4‰ using sample sizes of 40 mg wood powder. Tree cores from NE Italy show trends in pollution, evidenced through increasing concentrations of sulphur towards the youngest growth, and inverse trends in sulphur isotopes differentiating modern growth with light sulphur isotopes (+0.7‰) from pre-industrial growth (+7.5‰) influenced by bedrock composition. Comparison with speleothem records from the same location demonstrate replication, albeit offset in isotopic value due to groundwater storage. Using EA-IRMS, tree ring archives form a valuable resource for understanding local- to regional-scale sulphur pollution dynamics.
Show more [+] Less [-]Comparison of three labeled silica nanoparticles used as tracers in transport experiments in porous media. Part II: Transport experiments and modeling Full text
2014
Vitorge, Elsa | Szenknect, Stéphanie | Martins, Jean M.-F. | Barthès, Véronique | Gaudet, Jean-Paul
Three types of labeled silica nanoparticles were used in transport experiments in saturated sand. The goal of this study was to evaluate both the efficiency of labeling techniques (fluorescence (FITC), metal (Ag(0) core) and radioactivity (110mAg(0) core)) in realistic transport conditions and the reactive transport of silica nanocolloids of variable size and concentration in porous media. Experimental results obtained under contrasted experimental conditions revealed that deposition in sand is controlled by nanoparticles size and ionic strength of the solution. A mathematical model is proposed to quantitatively describe colloid transport. Fluorescent labeling is widely used to study fate of colloids in soils but was the less sensitive one. Ag(0) labeling with ICP-MS detection was found to be very sensitive to measure deposition profiles. Radiolabeled (110mAg(0)) nanoparticles permitted in situ detection. Results obtained with radiolabeled nanoparticles are wholly original and might be used for improving the modeling of deposition and release dynamics.
Show more [+] Less [-]Setting ozone critical levels for protecting horticultural Mediterranean crops: Case study of tomato Full text
2014
González Fernández, I. | Calvo, E. | Gerosa, G. | Bermejo, V. | Marzuoli, R. | Calatayud, V. | Alonso, R.
Seven experiments carried out in Italy and Spain have been used to parameterising a stomatal conductance model and establishing exposure– and dose–response relationships for yield and quality of tomato with the main goal of setting O3 critical levels (CLe). CLe with confidence intervals, between brackets, were set at an accumulated hourly O3 exposure over 40 nl l−1, AOT40 = 8.4 (1.2, 15.6) ppm h and a phytotoxic ozone dose above a threshold of 6 nmol m−2 s−1, POD6 = 2.7 (0.8, 4.6) mmol m−2 for yield and AOT40 = 18.7 (8.5, 28.8) ppm h and POD6 = 4.1 (2.0, 6.2) mmol m−2 for quality, both indices performing equally well. CLe confidence intervals provide information on the quality of the dataset and should be included in future calculations of O3 CLe for improving current methodologies.These CLe, derived for sensitive tomato cultivars, should not be applied for quantifying O3-induced losses at the risk of making important overestimations of the economical losses associated with O3 pollution.
Show more [+] Less [-]Pyruvate carboxylase as a sensitive protein biomarker for exogenous steroid chemicals Full text
2014
Liang, Xue-fang | Martyniuk, Christopher J. | Cheng, Gang | Zha, Jinmiao | Wang, Zijian
Assessing protein responses to endocrine disrupting chemicals is critical for understanding the mechanisms of chemical action and for the assessment of hazards. In this study, the response of the liver proteome of male rare minnows (Gobiocypris rarus) treated with 17β-estradiol (E2) and females treated with 17α-methyltestosterone (MT) were analyzed. A total of 23 and 24 proteins were identified with differential expression in response to E2 and MT, respectively. Pyruvate carboxylase (PC) was the only common differentially expressed protein in both males and females after E2- and MT-treatments. The mRNA as well as the protein levels of PC were significantly down-regulated compared with that of the controls (p < 0.05). Our results suggest that endocrine disruptors interfere with genes and proteins of the TCA cycle and PC may be a sensitive biomarker of exposure to exogenous steroid chemicals in the liver of fish.
Show more [+] Less [-]Long-term inverse modeling of Chinese CO emission from satellite observations Full text
2014
Yumimoto, Keiya | Uno, Itsushi | Itahashi, Syuichi
Carbon monoxide (CO) emissions in China in 2005–2010 were estimated by inversion, using the Green's function method from vertical CO profiles derived from MOPITT Version 5 satellite data and a tagged CO simulation, and validated with independent in situ observations from the World Data Centre for Greenhouse Gases. Modeling with a posteriori emission successfully reproduced CO outflow from the continent to the East China Sea, Sea of Japan, and Japanese islands during winter and spring, and compensated for underestimates in central and eastern China in summer. A posteriori emissions showed large seasonal variations in which December and March emissions were on average 23% larger than August emissions, consistent with other studies. Estimated Chinese CO emissions were 184.4, 173.1, 184.6, 158.4, 157.4, and 157.3 Tg/year for 2005–2010, respectively. The decrease after 2007 is partly attributed to Chinese socioeconomic conditions and improved combustion efficiency.
Show more [+] Less [-]Contrasting effects of water salinity and ozone concentration on two cultivars of durum wheat (Triticum durum Desf.) in Mediterranean conditions Full text
2014
Gerosa, Giacomo | Marzuoli, Riccardo | Finco, Angelo | Monga, Robert | Fusaro, Isa | Faoro, Franco
This paper reports the results of an Open-Top Chambers experiment on the responses of two durum wheat cultivars (Neodur and Virgilio) exposed to two different levels of ozone (charcoal-filtered air and ozone-enriched air) and irrigation water salinity (tap water as control and a 75 mM NaCl solution once a week).The stomatal conductance of the flag leaves was measured on four dates during May. Flag leaf samples were collected to detect ozone visible leaf injuries. At the end of the growing season, the yield/biomass and grain quality parameters were assessed. Saline irrigation caused significant reductions in gs, yield and grain quality in Neodur, while Virgilio was more tolerant. The yield response to ozone was almost negligible, with Virgilio, despite the higher susceptibility to visible leaf injuries, being more productive than Neodur.The responses to the combined stress were not consistent, with the main tendencies undoubtedly driven by the saline irrigation factor.
Show more [+] Less [-]Characteristics of particulate matter (PM10) and its relationship with meteorological factors during 2001–2012 in Beijing Full text
2014
Tian, Guangjin | Qiao, Zhi | Xu, Xinliang
Atmospheric pollution has become a significant challenge in Beijing metropolitan region, China. In this study, wavelet analysis and gray analysis were proposed to explore the temporal characteristics of particulate matter (PM10) and its relationships with meteorological factors during 2001–2012. The analysis indicated that air quality had got better significantly over the last decade. It was clearly interannual, seasonal, and monthly variation of atmospheric pollution, which represented that the air quality was the worst in spring, and got better in summer, subsequently tended to be more serious in autumn and winter. Generally atmospheric pressure was the most important meteorological feature influencing on PM10, followed by relative humidity and wind speed. However, the dominant meteorological factors influencing the atmospheric pollution were different in the four seasons. The results suggest that urban design and effective measures based on the relationship between meteorological factors and PM10 would be effective for improving atmospheric pollution.
Show more [+] Less [-]Temporal trends (1999–2010) of perfluoroalkyl acids in commonly consumed food items Full text
2014
Johansson, Jana H. | Berger, Urs | Vestergren, Robin | Cousins, Ian T. | Bignert, Anders | Glynn, Anders | Darnerud, Per Ola
The aim of this study was to determine how dietary exposure to PFAAs has changed over the period when major production changes occurred. Archived samples (1999–2010) of eggs, milk and farmed rainbow trout were analyzed by ultra performance liquid chromatography coupled to tandem mass spectrometry. Statistically significant decreasing trends were observed for concentrations of perfluorooctane sulfonic acid (PFOS) and perfluorohexane sulfonic acid (PFHxS) in fish (p < 0.002 and p < 0.032, respectively) and eggs (p < 0.001 for both compounds). Concentrations of PFOS in fish and eggs decreased by a factor of 10 and 40, respectively. In eggs there was also a statistically significant decreasing trend in concentrations of perfluorooctanoic acid (PFOA). The results of this study demonstrate that PFAA concentrations in food items from agricultural food chains and aquatic food chains close to sources respond rapidly to changes in environmental emissions. Implications for the overall understanding of human exposure are discussed.
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