275 research outputs found
L\u2019allattamento tra cura e cultura: dall\u2019Africa all\u2019ipertrofia tecnologica
Breastfeeding is a practice so far unobtrusively studied by cultural and medical anthropology, an act placed between nature and culture, between private and social women spheres and which, like birth and pregnancy. It expresses hierarchies in roles and gender relations among biopolitical dynamics which denote the organization of society itself. As a cultural practice, breastfeeding differs itself on the basis of the so-cial and ethnic belonging of the mother and the child, leading to ritual differences such as the law of the \u201ckinship of milk\u201d in muslim societies or the apothecary taboo of Sub-Saharan Africa. The paper reflects on how much this is occurring in Western society where breastfeeding is less and less widespread and how much the lobbies in-fluence technological and biomedical hypertrophy
Anthropological reflections on breastfeeding between care and culture
Breastfeeding is a practice so far unobtrusively studied by cultural and medical anthropology, an act placed between nature and culture, between private and social women spheres and which, like birth and pregnancy. It expresses hierarchies in roles and gender relations among biopolitical dynamics which denote the organization of society itself. As a cultural practice, breastfeeding differs itself on the basis of the social and ethnic belonging of the mother and the child, leading to ritual differences such as the law of the \u201ckinship of milk\u201d in muslim societies or the apothecary taboo of Sub-Saharan Africa. The paper reflects on how much this is occurring in Western society where breastfeeding is less and less widespread and how much the lobbies influence technological and biomedical hypertrophy
Reducing plastic pollution by recovery and recycling: evidence from a ‘Blue Economy’ project impacting policy-making in Italy
: This paper recognizes the relevance of the Seabed Cleaning Project, created by the Angelo Vassallo Sindaco Pescatore Foundation in 2010, and presents it as a tool to achieve benefits in environmental, social, and economic terms, in line with the innovative framework of the Blue Economy. The project suggests a practical, feasible, and scalable solution to plastic pollution that can be obtained thanks to the activity performed by fishermen in cooperation with the municipality and local community (in a multi-level cooperation perspective). The data show a significant reduction of plastic on the seafloor thanks to the project, but further research is needed in order to collect further positive outcomes from different applications of the project. In 2022, the "Salva Mare" Law was approved in the Senate, extending the good practices proposed by the Foundation nationwide and showing how small gestures and concrete actions can provide significant improvements in pursuit of a healthier, safer, greener, and smarter city for the future
Surface modification of food-grade PVC monitored by angle-resolved XPS
In this work the covalent functionalization of polyvinyl chloride (PVC) with (3-mercaptopropyl)trimethoxysilane (MPTMS) by nucleophilic substitution was investigated by X-ray photoelectron spectroscopy (XPS). The surface of food-grade PVC was characterized before and after treatment with ethanol and with 5% and 10% MPTMS solutions in ethanol. Special attention was paid to the determination of the chemistry, composition and thickness of the functionalized polymer surface by angle-resolved XPS (ARXPS). XPS analysis in standard mode and ARXPS spectra showed the presence of sulphur, silicon and oxygen from the MPTMS molecule. The quantitative analysis was in good agreement with the stoichiometry of the molecule. A small amount of chlorine, detected also at grazing angles, supported the formation of a layer, which resulted to be 2.2(0.2) nm thick including the hydrocarbon contamination usually detected by XPS on samples in contact with solutions. It is here demonstrated that XPS and ARXPS allow monitoring the surface functionalization and tune the conditions for achieving a good reproducibility during the functionalization of food-grade PVC by MPTMS. This is the starting point for further functionalization to obtain active food packaging with antimicrobial properties
The role of organic compounds in artificial saliva for corrosion studies: evidence from XPS analyses
Several formulations of artificial saliva have been used for corrosion studies. The present work focuses on the effect of different saliva formulations on the composition of the surface film formed on CuZn37 brass alloy by X-ray photoelectron spectroscopy (XPS), in order to clarify the corrosion mechanism of historical brass wind instruments when used. Three different saliva solutions, Darvell (D), Carter-Brugirard (C-B) and SALMO, were selected. They differ for the content of the organic compounds. The XPS results show the presence of a film made of CuSCN and zinc-phosphate on the brass exposed to C-B and SALMO. In the case of samples exposed to D formulation, phosphorus is not revealed, a decrease in the zinc content in the film is detected and the S 2p shows the presence of a second component together with the one ascribed to CuSCN. A comparison with the results obtained on the pure metals in the presence of the organic compounds suggests that the formation of zinc and copper complexes may lead to thin and less protective surface film and thus to the observed high corrosion rates
Influence of the Nb/P ratio of acidic Nb-P-Si oxides on surface and catalytic properties
In this work, two acidic Nb-P-Si mixed oxide gel-derived materials characterized by Nb/P molar ratios equal to 2 (5Nb2.5 P) and 1 (2.5NbP) were investigated for their surface and bulk properties in relation with the catalytic performances in the fructose dehydration reaction. The structural characteristics of the studied samples and the changes occurring after water treatment and after reaction were investigated by 29Si and 31P solid state nuclear magnetic resonance (MAS-NMR) and X-ray photoelectron (XPS) spectroscopies, while the characterization of their acidic properties was performed by base (2-phenylethylamine) adsorption in liquid phase. MAS-NMR showed that the phosphorus remains firmly anchored into the siloxane matrix after exposure to cold water for 5Nb2.5 P sample and XPS confirmed the homogeneity of the sample composition. Both samples exhibited good intrinsic acidity and maintained significant effective acidity in polar-protic liquids; 2.5NbP manifested a double amount of acid sites compared to 5Nb2.5 P, when 2-phenylethylamine is used as probe. Fructose dehydration to 5-(hydroxymethyl)furfural (HMF) on the two gel-derived catalysts was performed in water and in water-isopropanol solution under mild conditions (130 °C) working in a recirculation reaction line comprising a tubular catalytic reactor. In water-isopropanol solution, the samples displayed good performances, as expected thanks to the lively effective acidity. Around 45-50% fructose conversion was attained on both samples, with selectivity to HMF equal to about 50% on 2.5NbP gel-derived catalyst. Recycling tests showed satisfactorily stable activity during three consecutive runs
Multiphysics Design of High-Power Microwave Vacuum Window
This paper presents the Multiphysics Analysis of a High-
Power Microwave Window for a Ka-Band Klystron providing
16MW of peak power. After the optimization of the
electromagnetic performances, we analyze the effect of RF heating
effect and the stress of the pressure on the window. We also analyze
the multipactor effect, that is a common cause of window failure.
Using such approach, it is possible to realize a virtual prototype
capable to represent in a complete way the real prototype to be
manufactured
Surface and bulk modifications of amphibole asbestos in mimicked gamble's solution at acidic PH
This study aimed at investigating the surface modifications occurring on amphibole asbestos (crocidolite and tremolite) during leaching in a mimicked Gamble’s solution at pH of 4.5 and T = 37 °C, from 1 h up to 720 h. Results showed that the fibre dissolution starts with the release of cations prevalently allocated at the various M- and (eventually) A-sites of the amphibole structure (incongruent dissolution). The amount of released silicon, normalized to fibre surface area, highlighted a leaching faster for the crocidolite sample, about twenty times higher than that of tremolite. Besides, the fast alteration of crocidolite promotes the occurrence of Fe centres in proximity of the fibre surface, or possibly even exposed, particularly in the form of Fe(II), of which the bulk is enriched with respect to the oxidized surface. Conversely, for tremolite fibres the very slow fibre dissolution prevents the underlying cations of the bulk to be exposed on the mineral surface, and the iron oxidation, faster than the leaching process, significantly depletes the surface Fe(II) centres initially present. Results of this work may contribute to unravel possible correlations between surface properties of amphibole asbestos and its long-term toxicity
Surface and Bulk Modifications of Fibrous Erionite in Mimicked Gamble's Solution at Acidic pH
This study aimed at investigating both the surface and bulk modifications occurring on fibrous erionite during leaching in a mimicked Gamble's solution (MGS) at pH of 4.5 and T = 37 degrees C, up to one month of incubation. Samples were characterized by a multi-analytical approach: field-emission scanning electron microscopy (FE-SEM) was employed to investigate the morphological changes of both pristine and reacted fibres, inductively coupled plasma optical emission spectrometry (ICP-OES) was used to measure the concentration of the released cations; X-ray photoelectron spectroscopy (XPS) was exploited for highlighting possible modifications of surface chemistry; X-ray powder diffraction (XRPD) and high-resolution transmission electron microscopy (HR-TEM) were applied aiming to get information on the structural state of the fibres following the incubation. ICP results integrated with those obtained by both bulk- and surface-chemical characterization highlighted that erionite binds Na especially in the first 24 h of sample incubation in the MGS, following ion exchange with the extra framework cations, in particular Ca. Moreover, our new results show that the Na binding process caused structural modifications with the migration of Na toward the Ca2 site and redistribution of the cations within the erionite cage. TEM investigation pointed out that the interaction between erionite and MGS results in the formation of a new surface amorphous layer with an irregular lobate pattern on an earlier surface weathered layer. However, the silicate framework is not weakened by incubation in the MGS at acidic pH. In addition, on the basis of the Si release normalized to the mineral surface area, fibrous erionite resulted significantly more biodurable than amphibole asbestos. Notably, considering the primary role played by biodurability in inducing pathogenicity, this result certainly supports in vivo observations showing that erionite is much more tumorigenic than asbestos. Moreover, the ions released by erionite when immersed in MGS may trigger biological effects, such as those on lipid packing and membrane permeability. On this basis, we expect a regulatory definition that would provide protection from this carcinogenic fibre
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Influence of water on tribolayer growth when lubricating steel with a fluorinated phosphonium dicyanamide ionic liquid
This work aims to elucidate the role of environmental humidity on the tribological behavior of steel surfaces lubricated with an ionic liquid comprised of a fluorinated phosphonium cation-tributyl-3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-octyl-phosphonium-and a dicyanamide anion (i.e. N(CN) 2 - ). Ball-on-disk tribotests were carried out at room temperature and at various levels of relative humidity (RH). Water was found to be required to promote the formation of a tribofilm over the contact area. The reaction layer exhibited a patchy morphology, which resembles that observed formed with conventional antiwear additives such as ZnDTP. A surface-chemical analysis of the tribofilm indicated that the tribofilm is composed of fluorides, oxides, and phosphates, pointing to a stress-induced degradation of the ions and corrosion of the sliding counterparts, which is enabled by the presence of water at the sliding interface. © 2019 by the authors
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