773 research outputs found
Laminar flow through fractal porous materials: The fractional-order transport equation
The anomalous transport of a viscous fluid across a porous media with power-law scaling of the geometrical features of the pores is dealt with in the paper. It has been shown that, assuming a linear force-flux relation for the motion in a porous solid, then a generalized version of the Hagen-Poiseuille equation has been obtained with the aid of Riemann-Liouville fractional derivative. The order of the derivative is related to the scaling property of the considered media yielding an appropriate mechanical picture for the use of generalized fractional-order relations, as recently used in scientific literature
Platinum and Palladium Accumulation in Edible Mushroom Boletus aereus Bull. Growing in Unpolluted Soils of Sicily Region (Italy)
: 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)
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
Influence of Saharan Dust on the Composition of Urban Aerosols in Palermo City (Italy)
The Mediterranean Basin is involved in a recurring phenomenon wherein air masses laden with dust from North Africa impact the southern regions of the European continent. Saharan dust has been associated with increased mortality and respiratory symptoms. Palermo is a large coastal city, and in addition to the impact of desert dust particles, it has a mixture of anthropogenic sources of pollutants. In this study, we collected Saharan dust samples during August 2022 and October 2023, following a high-intensity Saharan dust event, and measured concentrations of 33 major and trace elements as well as Rare Earth Elements (REE). The mineralogical characterization of the deposition dust collected during Saharan events revealed calcite, dolomite, quartz, and clay minerals. The presence of palygorskite is indicative of Saharan events. Seven elements (Ca, Mg, Al, Ti, Fe, K, and Na) account for 98% of the total analyzed inorganic burden. Elemental ratios are valuable tools in atmospheric sciences for estimating sources of air masses. The results highlight that the city of Palermo is mainly affected by dust from the north-western Sahara
Multi-objective optimization of nitinol stent design
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
Comparison of dogs treated for primary immune-mediated hemolytic anemia in Tuscany, Italy and Texas, USA
This retrospective study compared clinical characteristics between dogs treated for IMHA by veterinary teaching hospitals in Tuscany, Italy and Texas, USA between 2010 and 2018
The Durability of Composite Wood-Steel Systems
Nell\u2019ambito della valutazione e del controllo della qualit\ue0 tecnologica in edilizia, la conoscenza del comportamento nel tempo dei prodotti e componenti complessi per l\u2019edilizia, risulta aspetto fondamentale, in particolare per quei prodotti tecnologicamente \u201cinnovativi\u201d per i quali la normativa non prevede ancora prove specifiche per valutarne la durabilit\ue0.
In particolare, oggi risulta sempre pi\uf9 diffuso l\u2019impiego di sistemi assemblati o con connessioni tra materiali di diversa natura, tra cui i sistemi legno-acciaio, ottenuti rinforzando le travi in legno lamellare con piastre in acciaio forate, incollati mediante una resina epossidica bicomponente.
Tali sistemi, che sono stati gi\ue0 oggetto di sperimentazione sul comportamento a flessione del sistema trave in legno lamellare e solaio collaborante in calcestruzzo, affidano la loro efficacia in riguardo alla resistenza ed alla rigidezza attraverso gli sforzi di taglio e gli spostamenti relativi che in caso di buona collaborazione legno-acciaio sono molto ridotti.
Il presente studio si occupa di indagare la durabilit\ue0 delle caratteristiche di aderenza legno-resina-acciaio del sistema, attraverso una sperimentazione condotta su campioni secondo le procedure della normativa ISO 15686.
Dopo una prima fase di studio del sistema agenti-azioni-effetti \ue8 stato messo a punto un ciclo di invecchiamento accelerato e sono state effettuate le indagini in laboratorio in camera climatica.
Il comportamento della connessione dopo vari livelli di invecchiamento \ue8 stato analizzato attraverso prove meccaniche di resistenza al taglio, azioni cui il sistema \ue8 sottoposto in esercizio, considerando sia le sollecitazioni climatiche che possono condizionare il comportamento dei singoli componenti del sistema: resina, acciaio e legno lamellare, sia il sistema nel suo insieme per cui risulta critico il comportamento all\u2019interfaccia legno-resina e resina-acciaio.
I risultati ottenuti hanno fornito indicazioni interessanti sul comportamento del sistema nel tempo. Infatti con l\u2019avanzare dei cicli di invecchiamento si \ue8 manifestata una progressiva riduzione del carico massimo a rottura, mantenendo caratteristiche di rigidezza elevata, con spostamenti relativi ridottissimi anche sui campioni pi\uf9 invecchiati
INCIDENTAL FINDING OF INTERRUPTED AORTIC ARCH IN AN ADULT PATIENT UNDERGOING URGENT PERCUTANEOUS CORONARY INTERVENTION
Interrupted Aortic Arch (IAA) is a rare congenital abnormality characterized by a complete
discontinuity of the aortic lumen, usually located after the origin of the left subclavian artery. IAA
is mainly diagnosed during childhood and has an extremely high mortality rate if left untreated.
Therefore, only a few cases have been diagnosed in adulthood. We report the case of a patient with
Non-ST Segment Elevation Myocardial Infarction (NSTEMI) and unknown IAA abnormality, who
underwent urgent percutaneous coronary angioplasty (PCI). It was not possible to reach ascending
aorta from the right radial artery because of the presence of tangled arteries connecting the prevertebral subclavian segment to the descending aorta. PCI was completed successfully through the
left radial artery. A post-procedural Angio-CT scan confirmed the Aortic Arch interruption. The
presented case highlights the crucial role of a multi-imaging modality approach for those patients
with such congenital abnormalities before undergoing PCI
The durability of carbon fiber/epoxy composites under hydrothermal ageing
Studies on fibre reinforced composites are now receiving greater attention. Industrial applications have been successful in areas like aerospace, automobile, marine, construction and sporting goods. The first generation of epoxy resins for use in carbon fibre composites are able to achieve optimized high stiffness modules and high heat resistance by a high crosslink density, reached through thermal curing. However, these formulations can be very toxic and brittle with low crack resistance, which was a major disadvantage for structural applications. In the last years the use of ionizing radiation as alternative to thermal curing has been proposed as an environmentally friendly process. Furthermore, in order to enhance toughness mechanical requirements for their applications, the formulation generally consists of blends of epoxy resins and engineering thermoplastics. In terms of durability (service life and reliability), in these materials it depends on different environmental conditions (temperature, moisture, etc.), and it is very important to know how their properties are modified after the exposure to different temperature and moisture absorption cycles. In this work carbon fibre composites produced by ionizing radiation induced curing of the epoxy based matrices have been subjected to thermal and moisture absorption ageing and the influence of these treatments on the thermal and mechanical properties has been investigated through dynamic mechanical thermal analysis and mechanical fracture toughness tests
Proteomic patterns of cultured breast cancer cells and epithelial mammary cells.
Breast cancer is one of the leading causes of death from cancer among women in western countries. The different types of breast cancer are grouped into invasive and noninvasive forms. Among the invasive types, ductal infiltrating carcinoma (DIC) is the most common and aggressive form. Using an in vitro model consisting of a DIC-derived cell line (8701-BC) and a nontumoral mammary epithelial cell line (HB2), we used the proteomics approach to search for homology and differences in protein expression patterns between tumoral and nontumoral phenotypes. Within an analysis window comprising 1,750 discernible spots we have currently catalogued 140 protein spots of potential interest. Fifty-eight of them were identified by gel matching with reference maps, immunodetection, or N-terminal microsequencing and classified into four functional groups. Twelve proteins were found differentially expressed in two cell lines: four were uniquely present in the neoplastic cell proteome and eight in epithelial cells. In addition, 53 proteins displayed different relative expression levels between the two cell lines, that is, 44 were more elevated in cancer cells and 9 in HB2 cells. Among proteins with greater relative abundance in cancer cells we identified glycolytic enzymes (or their isoforms), which may indicate that the known metabolic dysregulation in cancer can reflect oncogenic-related defects of glycolytic gene expression
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