1,721,285 research outputs found
Evaluation of the deposition, infiltration and drainage of the atmospheric pollutants in the vadose zone
Full text linkIn the last decades, a large effort has been carried out to reduce atmospheric pollutant emissions in Europe. However, despite the progresses of the last 30 years (Rogora et al., 2016), water and soil acidification, nutrition unbalance in forest trees, and eutrophication in surface waters are still of great concern. In particular, nutrients that fall on the ground from the atmosphere represent a minor component of the total nitrogen input to soils, especially when compared to agricultural, civil and industrial inputs (EEA, 2005). Although often underestimated, this source apportionment becomes a part of leaching from the soil to groundwater. Therefore, the overarching goal of this study is to identify anthropogenic background values of pollutants in groundwater, not related to direct sources of contamination (e.g., industrial wastes, leakages from sewage systems, fertilizers)
A Bayesian approach for the assessment of shallow and deep aquifers susceptibility to point sources contamination in the Province of Milan, Italy
Full text linkIn densely populated areas, urban and industrial activities are responsible for groundwater quality deterioration due to point sources contamination (Kuroda and Fukushi, 2008). In the Province of Milan (Northern Italy), the available water-quality data indicate the occurrence of high PCE+TCE and chromium concentrations in the unconfined shallow as well as in the confined deep aquifers. To cope with this problem, statistical methods can represent reliable tools to provide key information for groundwater management and protection
MECHANISMS INVOLVED IN THE LACK OF IMMUNE RECONSTITUTION DURING ANTIRETROVIRAL THERAPY IN HIV-INFECTED INDIVIDUALS
Full text linkIntroduction: HIV infection is characterized by CD4+ T cell immunodeficiency and chronic inflammation. Antiretroviral therapy (ART) leads to the recovery of CD4+ T cells by suppressing viral replication. However 15-30% of HIV-infected ART-treated patients fail to restore CD4+ T cells despite full viral suppression and they are known as “Immunological Non-Responders (INR)”. INRs are characterized by higher risk of AIDS progression and non-AIDS-related morbidity compared to HIV-infected ART-treated immunological responder (IR) patients. Several mechanisms have been involved in immune failure, however none of them provides a full explanation for the lack of immune reconstitution observed in INRs. Inflammasomes are multimeric protein platforms involved in the regulation of inflammatory responses, Th17 activity and in a high inflammatory form of programmed cell-death called “pyroptosis”. Pyroptosis was recently shown to play a major role in CD4+ T cell loss and to contribute to immune activation in HIV infection. The possible role of inflammasomes and pyroptosis in the lack of immune reconstitution has nevertheless not been investigated. We analyzed possible associations between inflammasome and Th17 activity, caspase-1 activation, pyroptosis and immune reconstitution in HIV-infected ART treated patients.
Methods: 39 HIV-infected patients on antiretroviral therapy for ≥24 months and plasma HIV-RNA<50cp/mL for ≥12 months, matched for nadir CD4+ T cell count were enrolled. Exclusion criteria: presence of actual opportunistic AIDS-related diseases, HBV or HCV co-infection, chronic inflammatory disorders, ongoing immunosuppressive therapy. Patients were classified as IRs or INRs if CD4+ T cell count was ≥500 or ≤350 cells/μL, respectively. Immune activation markers (HLA-DRII and CD38) and Th17 activity were evaluated by flow cytometry. Expression of genes involved in the inflammasome pathway and in pyroptosis were measured in unstimulated or LPS- and AT2 treated-HIV-1-stimulated cells. Pro-inflammatory cytokines, caspase-1 expression and microbial translocation markers (sCD14 and LPS) were quantified in plasma samples of all IRs and INRs.
Results: INR patients were older and had a higher prevalence of past AIDS-defining illnesses. HLADRII/CD4 were significantly increased in INRs. Higher median levels of Th17 T cells (CD4/IL17A/RORγT) were also seen in INRs in unstimulated, as well as in LPS- and AT2 treated-HIV-1 stimulated conditions. LPS-stimulated inflammasome (NLRP3) and pro-inflammatory cytokines gene expression (IL-1β, IL-18, TNFα, type-I IFNs, CCL3, IL-6) were significantly increased in INR patients. AT2-HIV-1 stimulation induced NLRP3 gene expression in both IRs and INRs; NLRP3 and IL-18 expression were nevertheless significantly increased in INRs compared to IRs. Higher caspase-1gene expression was seen in both unstimulated and AT2-HIV-1 stimulated cells of INRs, whereas caspase 3, 4 and 5 expression was similar in both groups. Plasma concentration of caspase-1 and IL-1βwere higher in INR compared to IR patients. No differences in microbial translocation markers could be detected between the two groups.
Conclusions: Increased immune activation levels and percentage of Th17 T cells and higher levels of inflammasome and caspase-1 expression are observed in INR patients. The upregulation of these pro-inflammatory mechanisms plausibly contributes to the persistent immune activation that characterize INRs. Notably, caspase-1 activation is likely to induce CD4+ T cell loss via pyroptosis, contributing to the unsatisfactory CD4+ T cell recovery seen in INRs
Applicazione di modelli reologici tempo dipendenti nell'evoluzione di deformazioni gravitative profonde
No full textA preliminary analysis of the effects of creep on the development of a deep-seated gravitational slope deformation (DSGSD), carried out by numerical modeling, is described. The slope rock mass evolution has been simulated applying different creep rheological models.
The studied DSGSD is located in the Central Italian Alps (Val S. Giacomo). It is characterized by three main scarps, different sets of tensile trenches, and counterscarps, mapped during a detailed geomorphological survey. The mechanical behaviour of the rock masses, in terms of elastoplastic parameters, has been defined on the base of laboratory and in situ tests.
In order to simulate this instability process a stress-strain-time numerical modeling has been applied by a finite difference numerical code (FLAC).
First, the slope conceptual model was represented by a constant dipping slope, uniform lithology (ortogneiss) and the presence of the water table at different elevations. The effects of different constitutive model laws have been considered: the visco-elastic Maxwell model; the visco-elastic Burger model and the elasto-visco-plastic Burger model. The modeling has been performed simulating the melting of the ancient glacier, starting from its maximum load.
Because of the difficulty to determine rock mass creep parameters, for each of the rheological models a sensitivity analysis has been performed, varying the physical-mechanical properties.
In accordance with the geological data, milonitic zones, characterized by low mechanical properties, have been introduced in the middle part of the slope, and two weathered superficial layers have been added, identifying new instability processes.The elasto-visco-plastic Burger constitutive model develop a stress/stain system more consistent with the present morphology
PROBLEMS WITH THE EUCLIDEAN FORMULATION OF HEAVY QUARK EFFECTIVE THEORIES
No full textWe discuss the formulation in euclidean space of the effective theory for heavy quarks at non-zero velocity, which is necessary for the implementation of the Isgur-Wise limit in lattice QCD simulations. In this theory the energy spectrum is unbounded from below and, even at the tree level, an ultraviolet cut-off on spatial momenta must be introduced. The continuum limit of the effective quark propagator in configuration space does not exist. It is however possible, at least in the non-interacting case, to construct sensible correlation functions in time and in spatial momenta. The application of the theory to lattice simulations seems very problematic
Linee Guida per le strategie di campionamento e l'elaborazione statistica e geostatistica dei dati ambientali
No full textLinee Guida per l'utilizzo di strumenti e la selezione di strategie di campionamento delle matrici ambientali
No full textRicostruzione mediante metodi numerici del flusso idrico all’interno della discarica di RSU sita in località La Torre (Teramo) Relazioni con le condizioni di stabilità dalla discarica
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