536 research outputs found

    Migration of chlorinated hydrocarbons in multilayer unconsolidated porous media: a case study from the Po Plain, Italy

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    Chlorinated solvents are the most ubiquitous organic contaminants found in groundwater since the last six decades. Due to their high degree of carcinogenicity/toxicity and the relatively high mobility and persistence, they represent a serious threat against the human health and the environment. These contaminants generally reach groundwater as Dense Non-Aqueous Phase Liquid (DNAPL) that can migrate through aquifers easier than aqueous contaminants. The complex phase partitioning to which chlorinated solvent DNAPLs can undergo (i.e. to the dissolved, vapor or sorbed phase), as well as their transformations (e.g. degradation), depend on the physico-chemical properties of the contaminants and on the features of the hydrogeological system in which they migrate. The hydrogeologic setting below the city of Ferrara (Po plain, northern Italy), which is affected by scattered contamination by chlorinated solvents, has been investigated. In particular, a limited-inspace high-resolution investigation was performed in one selected contaminated test-site, known as "Caretti site". Here, high-resolution vertical profiling of different kind of data (i.e. stratigraphic data, hydraulic heads, hydrochemical composition of water, stable isotopes of water and contaminants) were collected by means of multilevel monitoring systems and other innovative sampling and analytical techniques. The main goals of the research were to assess the intrinsic vulnerability of the aquifers and to identify the dynamics of migration and transformation of the chloroethene contaminants in relationship to the features of the hosting porous medium. The confined aquifers turned out to be more vulnerable to DNAPLs than aqueous contaminants due to the occurrence of microfractures in the overlying clayey aquitards. The presence of organic-rich deposits in the local stratigraphy enhanced the biodegradation of chloroethenes causing accumulation of Vinyl Chloride. The results are useful at the local scale, e.g. to interpret the origin of contamination in other sites of the Ferrara area, and also at the global scale, to better address future remediation and protection actions in similar settings

    Functional connectivity changes and their relationship with clinical disability and white matter integrity in patients with relapsing-remitting multiple sclerosis

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    Background and objective: To define the pathological substrate underlying disability in multiple sclerosis by evaluating the relationship of resting-state functional connectivity with microstructural brain damage, as assessed by diffusion tensor maging, and clinical impairments. Methods: Thirty relapsing–remitting patients and 24 controls underwent 3T-MRI; motor abilities were evaluated by using measures of walking speed, hand dexterity and balance capability, while information processing speed was evaluated by a paced auditory serial addiction task. Independent component analysis and tract-based spatial statistics were applied to RS-fMRI and diffusion tensor imaging data using FSL software. Group differences, after dual regression, and clinical correlations were modelled with GeneralLinear-Model and corrected for multiple comparisons. Results: Patients showed decreased functional connectivity in 5 of 11 resting-state-networks (cerebellar, executive-control, medial-visual, basal ganglia and sensorimotor), changes in inter-network correlations and widespread white matter microstructural damage. In multiple sclerosis, corpus callosum microstructural damage positively correlated with functional connectivity in cerebellar and auditory networks. Moreover, functional connectivity within the medial-visual network inversely correlated with information processing speed. White matter widespread microstructural damage inversely correlated with both the paced auditory serial addiction task and hand dexterity. Conclusions: Despite the within-network functional connectivity decrease and the widespread microstructural damage, the inter-network functional connectivity changes suggest a global brain functional rearrangement in multiple sclerosis. The correlation between functional connectivity alterations and callosal damage uncovers a link between functional and structural connectivity. Finally, functional connectivity abnormalities affect information processing speed rather than motor abilities

    Geological and hydrogeological features affecting migration, multi-phase partitioning and degradation of chlorinated hydrocarbons through unconsolidated porous media.

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    Chlorinated solvents are the most ubiquitous organic contaminants found in groundwater since the last five decades. They generally reach groundwater as Dense Non-Aqueous Phase Liquid (DNAPL). This phase can migrate through aquifers, and also through aquitards, in ways that aqueous contaminants cannot. The complex phase partitioning to which chlorinated solvent DNAPLs can undergo (i.e. to the dissolved, vapor or sorbed phase), as well as their transformations (e.g. degradation), depend on the physico-chemical properties of the contaminants themselves and on features of the hydrogeological system. The main goal of the thesis is to provide new knowledge for the future investigations of sites contaminated by DNAPLs in alluvial settings, proposing innovative investigative approaches and emphasizing some of the key issues and main criticalities of this kind of contaminants in such a setting. To achieve this goal, the hydrogeologic setting below the city of Ferrara (Po plain, northern Italy), which is affected by scattered contamination by chlorinated solvents, has been investigated at different scales (regional and site specific), both from an intrinsic (i.e. groundwater flow systems) and specific (i.e. chlorinated solvent DNAPL behavior) point of view. Detailed investigations were carried out in particular in one selected test-site, known as “Caretti site”, where high-resolution vertical profiling of different kind of data were collected by means of multilevel monitoring systems and other innovative sampling and analytical techniques. This allowed to achieve a deep geological and hydrogeological knowledge of the system and to reconstruct in detail the architecture of contaminants in relationship to the features of the hosting porous medium. The results achieved in this thesis are useful not only at local scale, e.g. employable to interpret the origin of contamination in other sites of the Ferrara area, but also at global scale, in order to address future remediation and protection actions of similar hydrogeologic settings

    Greenness, cognitive impairment and dementia: a systematic review and meta-analysis

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    BACKGROUND AND AIM: Many recent studies identified the benefits of green space exposure for the improvment of human health, especially mental health. The involved patways could be increased physical activity, improved sleep quality, reduced stress and also increased social interaction. The relation between greenness and cognitive decline, however, is still uncertain. METHODS: We searched epidemiological studies related to green space exposure and cognitive impairment and dementia in two electronic databases (PubMed and EMBASE) using terms related to residential greenness, including Normalized Difference Vegetation Index-NDVI, land cover, land use, green index, greenness, green space, urban park, urban green and recreational park, along with cognitive impairment, decline and dementia. A meta-analysis comparing the highest versus the lowest greenness exposure and risk of cognitive decline was performed using a random-effects model. RESULTS:Out of 64 studies retrieved from the online search 11 studies were eligible for the review. The majority of included reports used satellied-derived NDVI, while the remaining studies used land cover maps to determine the greenness-related exposure areas. Cognitive impairment or dementia risk are calculated using different exposure types (greenness within a buffer, the areal radius, or greenness of census block) at subject residential address. Overall, summary risk ratio-RR showed no effect of greenness on cognitive decline (RR 0.99, 95% confidence interval-CI 0.91-1.07), whereas a slight indication of a beneficial effect of NDVI emerged (RR 0.96, 95%CI 0.90-1.03). Two studies that reported correlation coefficents only did not suggest an association between cognitive impairment and dementia measurement. CONCLUSIONS:Overall, our study yielded limited evidence of a protective effect of greenness on cognitive decline. The rapid evolution of greenness definition over time and the limitations in exposure assessment, however, suggest the need to further investigate this issue in order to draw more reliable conclusions. KEYWORDS: Green space, Neurodegenerative outcomes, Environmental epidemiolog

    Microbial dynamics and fertility characteristics in compost from different waste and maturation processes

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    We evaluated the abundance of microbial functional groups involved in compost fertility, and the chemical parameters of maturity and quality most commonly analyzed in compost products. We employed compost produced using the same hydrolytic stage and two maturation processes (with and without earthworms) and with different organic wastes. Our aim was to propose a valid tool for measuring the quality standards of compost fertility from a microbial perspective. The products obtained from both maturation processes were highly variable in their chemical and biological composition (without following a general pattern). Because the results are so heterogeneous, proposing a microbial population as universal indicator of the degree of compost fertility is very difficult. However, the microbial community structure might be used as a maturity index, because the products that best fulfilled the chemical stability parameters were those with lowest number of populations in its community.Fil: Abril, Adriana. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; ArgentinaFil: Noe, L.. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; ArgentinaFil: Filippini, Maria Flavia Ramona. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias; ArgentinaFil: Cony, Mariano Anibal. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; ArgentinaFil: Martinez, L.. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Mendoza-san Juan. Estacion Experimental Agropecuaria Mendoza. Agencia de Extension Rural Lujan de Cuyo.; Argentin

    Low dispersion finite volume/element discretization of the enhanced Green-Naghdi equations for wave propagation, breaking and runup on unstructured meshes

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    International audienceWe study a hybrid approach combining a FV and FE method to solve a fully nonlinear and weakly-dispersive depth averaged wave propagation model. The FV method is used to solve the underlying hyperbolic shallow water system, while a standard P 1 finite element method is used to solve the elliptic system associated to the dispersive correction. We study the impact of several numerical aspects: the impact of the reconstruction used in the hyperbolic phase; the representation of the FV data in the FE method used in the elliptic phase and their impact on the theoretical accuracy of the method; the well-posedness of the overall method. For the first element we proposed a systematic implementation of an iterative reconstruction providing on arbitrary meshes up to third order solutions, full second order first derivatives, as well as a consistent approximation of the second derivatives. These properties are exploited to improve the assembly of the elliptic solver, showing dramatic improvement of the finale accuracy, if the FV representation is correctly accounted for. Concerning the elliptic step, the original problem is usually better suited for an approximation in H(div) spaces. However, it has been shown that perturbed problems involving similar operators with a small Laplace perturbation are well behaved in H 1. We show, based on both heuristic and strong numerical evidence, that numerical dissipation plays a major role in stabilizing the coupled method, and not only providing convergent results, but also providing the expected convergence rates. Finally, the full mode, coupling a wave breaking closure previously developed by the authors, is thoroughly tested on standard benchmarks using unstructured grids with sizes comparable or coarser than those usually proposed in literature

    Cell-based assay for the detection of chemically induced cellular stress by immortalized untransformed transgenic hepatocytes

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    BACKGROUND: Primary hepatocytes, one of the most widely used cell types for toxicological studies, have a very limited life span and must be freshly derived from mice or even humans. Attempts to use stable cell lines maintaining the enzymatic pattern of liver cells have been so far unsatisfactory. Stress proteins (heat shock proteins, HSPs) have been proposed as general markers of cellular injury and their use for environmental monitoring has been suggested. The aim of this work is to develop a bi-transgenic hepatocyte cell line in order to evaluate the ability of various organic and inorganic chemicals to induce the expression of the HSP70 driven reporter gene. We previously described transgenic mice (Hsp70/hGH) secreting high levels of human Growth Hormone (hGH) following exposure to toxic compounds in vivo and in vitro in primary cultures derived from different organs. In addition, we also reported another transgenic model (AT/cytoMet) allowing the reproducible immortalization of untransformed hepatocytes retaining in vitro complex liver functions. RESULTS: The transgenic mouse line Hsp70/hGH was crossed with the AT/cytoMet transgenic strain permitting the reproducible immortalization of untransformed hepatocytes. From double transgenic animals we derived several stable hepatic cell lines (MMH-GH) which showed a highly-differentiated phenotype as judged from the retention of epithelial cell polarity and the profile of gene expression, including hepatocyte-enriched transcription factors and detoxifying enzymes. In these cell lines, stresses induced by exposure to inorganic [Sodium Arsenite (NaAsO(2)) and Cadmium Chloride (CdCl(2))], and organic [Benzo(a)Pyrene (BaP), PentaChloroPhenol (PCP), TetraChloroHydroQuinone (TCHQ), 1-Chloro-2,4-DiNitro-Benzene (CDNB)] compounds, specifically induced hGH release in the culture medium. CONCLUSIONS: MMH-GH, an innovative model to evaluate the toxic potential of chemical and physical xenobiotics, provides a simple biological system that may reduce the need for animal experimentation and/or continuously deriving fresh hepatocytes

    A methodological approach for the identification of sulphate sources in the Portoscuso area (south-western Sardinia)

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    Several detrimental effects due to intense industrial activities affect the groundwater of the Portoscuso area (SW Sardinia, Italy) such that the Italian Government has designed the whole territory as a contaminated site of national interest (D.M., March 12, 2003). Groundwater pollution is a crucial environmental issue in this area, where a volcanic ignimbrite succession up to 500 m thick outcrops, locally covered by sand deposits of variable thickness. Groundwater upgradient to the industrial district shows sulphate concentrations exceeding the background value of 450 mg/L calculated for the area (Vecchio et al., 2011). In order to verify the origin of sulphate, multidisciplinary investigations were carried out on the geochemical features and stable isotope ratios in groundwater
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