137 research outputs found
Behaviour of Metal(loid)s at the Sediment-Water Interface in an Aquaculture Lagoon Environment (Grado Lagoon, Northern Adriatic Sea, Italy)
No full textThe cycling of metal(loid)s at the sediment–water interface (SWI) was evaluated at two selected sites (VN1 and VN3) in an active fish farm in the Grado Lagoon (Northern Adriatic, Italy). In situ experiments using a transparent benthic chamber and the collection of short sediment cores
were performed, to investigate the behavior of metal(loid)s in the solid (sediments) and dissolved (porewaters) phases. Total and labile concentration of metal(loid)s were also determined in sediments, to quantify their potential mobility. Comparable total concentrations were found at both sites, excluding As, Mn, Pb and V, which were higher at VN3. Metal(loid) porewater profiles showed a diagenetic sequence and a close dependence with redox (suboxic/anoxic) conditions in the surface sediments. Positive diffusive fluxes along with benthic fluxes, particularly at the more oxic site, VN1, were found for almost all metal(loid)s, indicating their tendency to migrate towards the overlying water column. Despite sediments at two sites exhibiting high total metal(loid) concentrations and moderate effluxes at the SWI, the results suggest that they are hardly remobilized from the sediments. Recycling of metal(loid)s from the SWI would not constitute a threat for the aquatic trophic chain in the fish farm
Questione di pelle: il rischio da esposizione cutanea a sostanze tossiche
No full textIn passato la cute veniva generalmente considerata come una barriera impenetrabile dall’esterno, invece, nel tempo, si è rivelata come una possibile via d’ingresso di sostanze tossiche all’interno dell’organismo. Tale fenomeno - sfruttato anche in ambito farmaceutico per somministrare alcuni tipi di medicinali mediante veicolazione transdermica - presenta un rischio non trascurabile per la salute, soprattutto in particolari ambiti professionali, dove il lavoratore è esposto quotidianamente a composti potenzialmente dannosi.
A differenza della penetrazione per via respiratoria, il rischio legato all’assorbimento cutaneo è scarsamente percepito, di conseguenza non viene data la giusta importanza all’utilizzo di dispositivi di protezione individuali per la pelle, con conseguenze anche molto gravi, fino alla comparsa di patologie invalidanti. Cerchiamo di capire assieme questo fenomeno poco conosciuto e vediamo alcuni esempi di contaminanti che possono entrare nel nostro organismo attraverso la cute
Povidone iodine skin absorption: An ex-vivo study
No full textPovidone iodine is a water-soluble complex used to disinfect the skin surface and it exerts prolonged germicidal action against a broad spectrum of germs. Indeed, it is often applied on burned skin, large wounds, deep tissues or mucosa. Notably some surgical hand-scrub solutions, which are considered safe antiseptics, contain large amounts of iodine that can be absorbed by skin. The aim of present study was to study the skin absorption of iodine after the application on the skin of povidone-iodine solution, used by health care workers during surgical procedure. We use Franz diffusion static cells with human skin. After 24h from the beginning of our measurement the iodine concentration in the receiving compartment was 11.59±6.3μg/cm(2). The medium flux calculated was 0.73±0.33μg/cm(2)/h with a lag time of 8.9±1.5h. These in vitro results confirmed that povidone iodine could pass through the skin in a relevant amount that can explain the clinical findings in burned or surgically treated patients. In professional use the repetitive contact with povidone iodine, also as soap, can cause iodine skin permeation that must be considered when the washing procedures are repeated more than 20 times a day
ICP-AES analysis of Bizantine anonymous copper coins from the XI century and comparison wih micro-EDXRF non-destructive analysis
No full text
Iron Gall Inks: is copper a key element for historical and archaeometric information on medioeval manuscripts? An applied reserach focused on Guarnerio D’Artegna
No full text
Nanostructured Pd–Pt nanoparticles: evidences of structure/performance relations in catalytic H2production reactions
No full textA widespread approach to modulate the performances of heterogeneous catalysts is the use of bimetallic nanoparticles (NPs) as the active phase. However, studying the relationship between the NPs structure and catalytic properties requires well-defined systems, having uniform composition, size and nanostructure, which cannot be achieved by traditional methods (e.g. impregnation). Here, we developed wet-chemistry synthetic routes to prepare PdPt NPs or Pt-core@Pd-shell NPs of small size and well-controlled composition and structure, protected by mercaptoundecanoic acid (MUA) moieties. The pristine NPs were tested for H2 production by NH3BH3 hydrolysis, in order to systematically investigate the effect of composition and of synthetic route on the activity of the systems. Depending on the preparation method, two distinct trends of activity were observed, rationalized in terms of the extent of surface functionalization by MUA. The MUA protective layer was found to effectively stabilize the NPs dispersion while maintaining high activity in certain cases (Pt-rich NPs), and was demonstrated to be essential for catalyst recycling. In order to further study structure-activity relationships of PdPt NPs after ligand removal, nanostructured PdPt@CeO2-based catalysts were prepared by self-assembly route. Regardless of the starting NPs structure (alloy or core-shell), similar water gas shift reaction performances were observed, due to the structural rearrangements occurring upon oxidation and reduction thermal treatments, which led to the formation of Pt-rich core@PdPt-shell under reducing conditions
- …
