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1.
A yearlong sampling campaign (2012–2013) was conducted in six major cities of the Veneto region to investigate the spatial-temporal trends and the factors affecting the polycyclic aromatic hydrocarbon (PAHs) variations and identify the local sources. Sixty samples per city were collected for analyses in every alternate month (April, June, August, October, December, and February): 10 samples per sampling site in 10 consecutive days of the months selected. Samples were ultrasonically extracted with acetonitrile and processed through high-performance liquid chromatography. Total Σ-PAH concentrations ranged from 0.19 to 70.4 ng m?3 with a mean concentration of 11.5 ng m?3. The mean benzo[a]pyrene (BaP) concentration reached 2.0 ng m?3, which is two-times higher than the limit set by the European Union. BaP contributed for 17.4% to the total concentration of PAHs, which showed the same pattern across the region with maxima during cold months and minima in the warm period. In this study, PAHs showed an inverse relationship with temperature, solar radiation, wind speed, and ozone. According to this study, biomass burning for household heating and cooking, followed by gaseous PAHs absorption on particles due to low atmospheric temperature, were the main reasons for increasing PAHs concentration in winter. Health risk, evaluated as lifetime lung cancer risk (LCR), showed a potential carcinogenic risk from the airborne BaPTEQ six-fold higher in the cold season than in the warm one. Diagnostic ratios and conditional probability functions were used to locate the sources, and results confirmed that local emission, overall domestic heating, and road transport exhausts were responsible for higher concentration rates of PAHs as well as of PM2.5.  相似文献   
2.
The loss of yields from agricultural production due to the presence of pests has been treated over the years with synthetic pesticides, but the use of these substances negatively affects the environment and presents health risks for consumers and animals. The development of agroecological systems using biopesticides represents a safe alternative that contributes to the reduction of agrochemical use and sustainable agriculture. Microalgae are able to biosynthesize a number of metabolites with potential biopesticidal action and can be considered potential biological agents for the control of harmful organisms to soils and plants. The present work aims to provide a critical perspective on the consequences of using synthetic pesticides, offering as an alternative the biopesticides obtained from microalgal biomass, which can be used together with the implementation of environmentally friendly agricultural systems.  相似文献   
3.
Environmental Economics and Policy Studies - Streets are an essential element of cities, and their design has a profound impact on their functionality to the movement of people and their...  相似文献   
4.
The biodegradability of a multicomponent system based on biotechnological occurring polyester (poly(-hydroxybutyrate-co--hydroxyvalerate) (PHBV)) with inclusion of acrylate elastomer (polybutylacrylate) (PBA) was investigated. A bacterium which produced extracellular enzymes that degrades PHBV even when blended with PBA was isolated and tentatively designated asAureobacterium saperdae. It was observed, by morphological investigation, that, while the bacterial degradation was permitted for PBA content of 20% by weight, it was inhibited for PBA content of 30%, owing to the occurrence of a rubbery layer that prevents to the bacteria an easy accessibility in the PHBV-rich regions. In fact, owing the bacterial growth, only PHBV was metabolized, whereas no degradation of PBA was detected for blend samples. It was confirmed that the degradation proceeded via surface erosion of PHBV also in the blends. Finally, mechanical tests on PHBV/PBA specimens as a function of degradation extent have shown different behavior of the blends at different the PBA content. Thermal analysis of blends and PHBV has been reported, too  相似文献   
5.
Prenatal diagnosis of heterozygous achondroplasia at 25 weeks is described. First-level fetal ultrasonography demonstrated short long bones of the lower limbs. Second-level examination showed a large head; shortened femur, fibula, and tibia; a ‘trident’-shaped hand; and an abnormal facial profile.  相似文献   
6.
The Henze precipitate, a peculiar blue-green microparticulate obtained by lysis of the blood cells of the ascidian Phallusia mammillata (Protochordata), was investigated with atomic force microscopy (AFM), scanning electron microscopy (SEM) and X-ray microanalysis. The precipitate was collected from the Henze solution, an unstable red-brown product obtained by treating blood with distilled water, whose degradation yields a characteristic blue-green product. The microparticulates measured 50–100 µm in diameter and appeared irregular in shape. SEM examination showed smooth, roughly round boundaries. The microparticulate surface examined with AFM appeared as an irregular matrix formed by 70–320-nm-wide mammillate composites, including and embedding small (500–800 nm wide) crystal-like multilayered formations. X- ray analysis showed that the elements present in these same precipitates were mainly C, Si, Al and O. The microparticulate composition appeared close to those of natural waxes or lacquers, embedding amorphous silicates and/or other Si–Al components. The unusual occurrence of Si in ascidian blood and its role are discussed.  相似文献   
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