1,089 research outputs found

    Platinum and Palladium Accumulation in Edible Mushroom Boletus aereus Bull. Growing in Unpolluted Soils of Sicily Region (Italy)

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    : Human exposure to certain metals occurs indirectly through diet. This study was conducted to determine the content of Pt and Pd in fruiting bodies of Boletus aereus Bull. collected from several wooded areas of Sicily with different substrates (sedimentary and volcanic) with limited anthropogenic influence. Determinations were performed by coupled plasma-mass spectrometry (ICP-MS) to quantify Pt and Pd. The concentrations of investigated Pt and Pd in mushroom samples ranged from 0.31 to 3.09 ng g-1 for palladium and 0.21 to 4.22 ng g-1 for platinum. The results of the present study suggest that commonly consumed Boletus aereus mushrooms do not accumulate significant levels of Pt and Pd as demonstrated by bioconcentration factor (BCF) values, and their content is lower than in other food products. Additionally, based on the calculated daily intake rates of Pt and Pd, it can be concluded that occasional consumption of fruiting bodies of B. aereus collected in Sicily is safe. The proposed methodological approach appears to be fully adequate for the reliable quantification of Pt and Pd. The data obtained in this investigation confirm that mushrooms are probative of a significant portion of the total exposure to PGEs due to the diet

    Determination of Water-Soluble Trace Elements in the PM10 and PM2.5 of Palermo Town (Italy)

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    This study contributes to the current knowledge on the solubility of trace elements in the atmospheric particulate matter of the urban area of Palermo. Daily sample filters of PM10 and PM2.5 were collected in monitoring stations within and outside the urban area, characterized by variable traffic density. The bulk of compositions in PM10 and PM2.5 were determined by ICP-MS. The water-soluble trace elements (WSTE) and major ion components of particulate matter were determined by ICP-MS and ion chromatography, respectively. A significant difference in the metals content was observed between the samples taken in urban areas and those from suburban areas. The calculated enrichment factor highlights the high values for Cu, Mo, Sb, V, and Zn, confirming the contribution of human activities. The leaching test was applied to PM10 and PM2.5 filters and showed different behaviors and transport of metals and metalloids. The calculated leaching coefficient highlights the metals typically produced by anthropic activities, compared to those of geogenic origin, are much more soluble in water and have greater mobility. The factor analysis was used to identify the sources of water-soluble ions. The main sources are anthropic, geogenic, and sea spray. The final objective of this study is to obtain, with the aid of leaching experiments on PM2.5 and PM10 filter samples, information about the bioavailability and mobility of the different metals and metalloids that could be used as the scientific basis for public health intervention and to raise the prevention and control of heavy metal pollution in the urban environment, especially in densely populated areas

    How the COVID-19 pandemic is changing online food shopping human behaviour in Italy

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    The advent of the Internet has significantly changed consumption patterns and habits. Online grocery shopping is a way of purchasing food products using a web-based shopping service. The current COVID-19 pandemic is determining a rethinking of purchase choice elements and of consumers\u2019 behavior. This work aims to investigate which characteristics can affect the decision of online food shopping during the pandemic emergency in Italy. In particular, the work aims to analyze the effects of a set of explanatory variables on the level of satisfaction for the food online shopping experience. For achieving this aim, the proportional odds version of the cumulative logit model is carried out. Data derive from an anonymous on-line questionnaire administrated during the first months of the pandemic and filled by 248 respondents. The results of this work highlight that people having familiarity with buying food online, that have a higher educational level and consider food online channels easy to use, appear more satisfied for the food online shopping experience. These findings can be crucial for the future green global challenges as online shopping may help to reach competitive advantages for company sustainability

    Multi-objective optimization of nitinol stent design

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    Nitinol stents continuously experience loadings due to pulsatile pressure, thus a given stent design should possess an adequate fatigue strength and, at the same time, it should guarantee a sufficient vessel scaffolding. The present study proposes an optimization framework aiming at increasing the fatigue life reducing the maximum strut strain along the structure through a local modification of the strut profile.The adopted computational framework relies on nonlinear structural finite element analysis combined with a Multi Objective Genetic Algorithm, based on Kriging response surfaces. In particular, such an approach is used to investigate the design optimization of planar stent cell.The results of the strut profile optimization confirm the key role of a tapered strut design to enhance the stent fatigue strength, suggesting that it is possible to achieve a marked improvement of both the fatigue safety factor and the scaffolding capability simultaneously. The present study underlines the value of advanced engineering tools to optimize the design of medical devices

    Dynamic heterodyne near field scattering

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    The technique heterodyne near field scattering (HNFS), originally developed for low-angle static light scattering, has also been implemented for carrying out dynamic light scattering. While the classical dynamic light scattering method measures the intensity-intensity correlation function, dynamic HNFS gives directly the field-field correlation function, without any assumption on the statistical properties of the sample, as the ones required by the Siegert relation. The technique has been tested with calibrated Brownian particles and its performances compared to those of the classical dynamic light scattering method.The technique heterodyne near field scattering (HNFS), originally developed for low-angle static light scattering, has also been implemented for carrying out dynamic light scattering. While the classical dynamic light scattering method measures the intensity-intensity correlation function, dynamic HNFS gives directly the field-field correlation function, without any assumption on the statistical properties of the sample, as the ones required by the Siegert relation. The technique has been tested with calibrated Brownian particles and its performances compared to those of the classical dynamic light scattering method. \ua9 2008 American Institute of Physics

    Heterodyne speckle velocimetryof Poiseuille flow

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    We review the technique named heterodyne speckle velocimetry and present two applications for testing the method with a fluid moving under the conditions of Poiseuille flow. The fluid was seeded with small tracking particles diameter 300 nm and fluxed between the two parallel planes of a cell with constant or variable cross section. In the first case the velocity distribution was constant along the direction parallel to the planes and was in excellent agreement with the expected Poiseuille profile along the orthogonal direction. In the second case, where velocity gradients were present also along the planes, the technique was able to reconstruct both the orthogonal Poiseuille profile and the in-plane two dimensional mapping of the velocity vectors, with the possibility of measuring the fluid flux within an accuracy of 1%

    Green composites based on pla and agricultural or marine waste prepared by fdm

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    Three dimensional-printability of green composites is recently growing in importance and interest, especially in the view of feasibility to valorize agricultural and marine waste to attain green fillers capable of reducing bioplastic costs, without compromising their processability and performance from an environmental and mechanical standpoint. In this work, two lignocellulosic fillers, obtained from Opuntia ficus indica and Posidonia oceanica, were added to PLA and processed by FDM. Among the 3D printed biocomposites investigated, slight differences could be found in terms of PLA molecular weight and filler aspect ratio. It was shown that it is possible to replace up to 20% of bioplastic with low cost and ecofriendly natural fillers, without significantly modifying the processability and the mechanical performance of the neat matrix; at the same time, an increase of surface hydrophilicity was found, with possible positive influence on the biodegradability of such materials after disposal

    Probing Transverse Coherence with the Heterodyne Speckle Approach: Overview and Perspectives☆

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    Abstract The properties of spatial coherence of radiation emitted by relativistic electrons is far from being trivial. Assessing the coherence of high-brilliance X-ray sources (3rd generation synchrotrons or free electron lasers) is of crucial importance for machine diagnostics, as well as in planning experiments exploiting coherent techniques. The Heterodyne Speckles method, firstly described by Alaimo et al. (2009), is a valuable alternative to standard methods (e.g. Young's interferometer) which 1) provides a direct measure of transverse coherence without any a-priori assumption, 2) provides a full 2D map of coherence, 3) is capable of one shot, time-resolved measures, 4) is scalable over a wide range of wavelengths. It relies upon the statistical analysis of radiation scattered by spherical particles randomly distributed and suspended in a fluid. Here we give an overview of this method, from the theoretical framework to the operating conditions to be adopted in order to obtain coherence measurements in several conditions
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