263 research outputs found
Thermal impact evaluation of an open loop heat pump system: integrated approach with project data, numerical modeling and groundwater monitoring
Open loop, geotermal system, low enthalpy, numerical simulation, FEFLOW-DHI
Hexavalent Chromium: Analysis of the Mechanism of Groundwater Contamination in a Former Industrial Site in the Province of Vicenza (Northern Italy)
The study consisted in the analysis of the mobilization mechanisms of hexavalent chromium (Cr(VI)) into groundwater from a decommissioned contaminated factory. The site is located in the Province of Vicenza and formerly was a chrome-plating plant. The subsoil consists predominantly of gravelly deposits with a thickness of at least one hundred meters. An unconfined aquifer is present with water table at about 23 m depth bgl. During the seven years of monitoring (2008-2014), the fluctuation of groundwater level was more than 6 m; hydraulic conductivity is about 1.0E-03 m/s and groundwater seepage velocity about 12 m/day. At the area of the source of contamination, the unsaturated soil is contaminated by hexavalent chromium throughout the thickness: concentrations range from 200 to 500 mg/kg. At the bottom of zone of groundwater level fluctuation, the hexavalent chromium concentration decreases to below the detection limit. The available data (e.g. hexavalent chromium concentrations in groundwater, groundwater level, local rainfall) give the opportunity to assess the effects, on the magnitude of groundwater contamination, of the effective infiltration versus the fluctuation of groundwater level. The main analysis was performed on a statistical basis, in order to find out which of the two factors was most likely related to the periodic peaks of hexavalent chromium concentration in groundwater. Statistical analysis results were verified by a mass balance. Data show that at the site both the effective infiltration through the unsaturated zone and the leaching of soil contaminated by groundwater, when it exceeds a certain piezometric level, lead to peak concentrations of hexavalent chromium, even if with characteristics and effects different
Future regulation for the reduction of PFAS pollution in aquifers and for the improvement of drinking water quality
This Technical Note, inspired by some recent international scientific contributions, focuses attention on the relationships existing between the diffusion of per- and polyfluoroalkyl substances and the drinking water environmental sector. Firstly, the analysis takes into consideration published data to highlight the ubiquity of PFAS in the aquifers of various nations. There are also some health implications resulting from the exposure of individuals to PFAS following the ingestion of contaminated water. The technical background is then compared with the current state of the regulatory framework, indicating the reasons, collateral initiatives and precautionary criteria that must guide an urgent and effective remodeling of the law
Chemical composition of the essential oils from leaves and flowers of Passiflor sexocellata and Passiflora trifasciata
The chemical composition of the essential oils of Passiflora sexocellata and Passiflora trifasciata (Passifloraceae, subgenus Decaloba) were
studied for the first time. Essential oils were obtained by steam distillation of fresh leaves and flowers. The chemical composition
was assessed by using GC/FID and GC/MS. For P. sexocellata leaves, the optimized analytical procedure allowed the identification
of 33 compounds (75% of the total oil composition) and 29 (74% of the total oil composition) in flowers. Regarding P. trifasciata,
35 compounds (76% of the total oil composition) were detected in leaves and 32 (71% of the total oil composition) in flowers.
Terpenes and mono unsaturated hydrocarbons were quantified as major constituents of the volatile fraction in flowers (17.0 to
52.6%) and (13.7 to 20.0%). Organic acids were detected in both leaves and flowers with a percentage ranging from 3.3% to 32.0%.
Aldehydes were also detected in leaves (12.6 to 41.4%) and in flowers (1.4 to 5.1%). The GC/MS analyzes allowed alcohols to be
detected in leaves (20.6 to 42.9%) and in flowers (8.2 to 18.1%). These compounds represent the most important feature of the
large Passiflora family. Moreover, a critical role in the coevolved mechanisms of pollinators' interaction has been investigated
The effects of low enthalpy geothermal system on groundwater of the Cesine wetland
Cesine Wetland, Salento, low-enthalpy geothermal power plant, heat transport numerical model
Measurement of paclitaxel and its metabolites in human plasma using liquid chromatography/ion trap mass spectrometry with a sonic spray ionization interface
Volatile Organic Compounds (VOCs) Diversity in the Orchid Himantoglossum robertianum (Loisel.) P. Delforge from Sardinia (Italy)
Volatile Organic Compounds (VOCs) are produced by plants to address a variety of physiological and ecological tasks (among others, stress resistance, and pollinator attraction). Genetics is a key factor in determining plantsâ VOCs content and emission, nevertheless, environment strongly influences VOCs profiles in plants. Orchids are a widespread group of plants that colonize diverse environments and rely on complex and refined pollination mechanisms to reproduce. Orchids VOCs are rarely studied and discussed in relation to growing conditions. In the present study, we compare the volatile profiles of inflorescences of Himantoglossum robertianum (Loisel.) P. Delforge sampled in six ecologically diverse populations on Sardinia Island (Italy). The essential oils obtained by steam distillation were characterized by GCâFID and GCâMS analysis. A total of 79 compounds were detected, belonging to the chemical classes of saturated hydrocarbons, esters, alcohols, ketones, unsaturated hydrocarbons, sesquiterpenes, oxygenated terpenes, terpenes, acids, and aldehydes. Multivariate statistics separated H. robertianum populations based on their chemical profiles. Differences were positively linked to the distance separating populations and reflected climatological features of the sampling sites. Interestingly, our results differed from those available in the literature, pointing out the high variability of VOCs profiles in this foodâdeceptive orchid
Methylmercury Poisoning Induces Cardiac Electrical Remodeling and Increases Arrhythmia Susceptibility and Mortality
This study aims to investigate the cardiac electrical remodeling associated with intoxication by methylmercury (MeHg). We evaluated the chronic effects of MeHg on in vivo electrocardiograms and on ex vivo action potentials and depolarizing (ICa-L) and repolarizing (Ito) currents. The acute effect of MeHg was evaluated on HEK293 cells expressing human ERG, Kv4.3 and KCNQ1/KCNE1 channels. Chronic MeHg treatment increased QTc and TpeakâTend interval duration, prolonged action potential duration and decreased amplitude of Ito and ICa-L. In addition, heterologously expressed IhKv4.3, IhERG or IhKCNQ1/KCNE1 decreased after acute exposure to MeHg at subnanomolar range. The introduction of the in vitro effects of MeHg in a computer model of human ventricular action potentials triggered early afterdepolarizations and arrhythmia. In conclusion, cardiac electrical remodeling induced by MeHg poisoning is related to the reduction of Ito and ICa-L. The acute effect of MeHg on hKv4.3; hERG and hKCNQ1/KCNE1 currents and their transposition to in silico models show an association between MeHg intoxication and acquired Long QT Syndrome in humans. MeHg can exert its high toxicity either after chronic or acute exposure to concentrations as low as picomolar.This work was supported by grants from the Gobierno Vasco PIBA2018-58 and GIC18/150
FossilSim:An r package for simulating fossil occurrence data under mechanistic models of preservation and recovery
1.Key features of the fossil record that present challenges for integrating palaeontological and phylogenetic datasets include (i) nonâuniform fossil recovery, (ii) stratigraphic age uncertainty and (iii) inconsistencies in the definition of species origination and taxonomy.
2.We present an r package FossilSim that can be used to simulate and visualise fossil data for phylogenetic analysis under a range of flexible models. The package includes intervalâ, environmentâ and lineageâdependent models of fossil recovery that can be combined with models of stratigraphic age uncertainty and species evolution.
3.The package input and output can be used in combination with the wide range of existing phylogenetic and palaeontological r packages. We also provide functions for converting between FossilSim and paleotree objects.
4. Simulated datasets provide enormous potential to assess the performance of phylogenetic methods and to explore the impact of using fossil occurrence databases on parameter estimation in macroevolution.ISSN:2041-210XISSN:2041-209
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