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Novel solid-phase microextraction coatings based on the use of multiwalled carbon nanotube–cyclodextrin (MWCNT-CD) nanocomposites were developed for the determination of 16-priority polycyclic aromatic hydrocarbons at ultratrace levels in... more
Novel solid-phase microextraction coatings based on the use of multiwalled carbon nanotube–cyclodextrin (MWCNT-CD) nanocomposites were developed for the determination of 16-priority polycyclic aromatic hydrocarbons at ultratrace levels in snow samples. The performance of both β- and γ-CD was tested to increase the detection capabilities towards the heaviest and most lipophilic compounds, i.e., five- and six-ring PAHs. To facilitate the interactions of MWCNTs with CDs, an oxidation procedure using both HNO3 and H2O2 was applied, obtaining superior results using MWCNTs-H2O2-γ-CD fiber. Detection and quantitation limits below 0.7 and 2.3 ng/L, RSD lower than 21%, and recoveries of 88(± 2)–119.8(± 0.4)% proved the reliability of the developed method for the determination of PAHs at ultratrace levels. The complexation capability of the γ-CD was also demonstrated in solution by NMR and fluorescence spectroscopy studies and at solid state by XRD analysis. Finally, snow samples collected in...
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Hybrid superparamagnetic nanoparticles functionalized with odorant binding proteins for Candida albicans treatment.
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In this paper, an investigation of the properties of Cu and Cu/MgO nanoparticles (NPs) is presented. The NPs were obtained with gas-phase synthesis, and the MgO shells or matrices were formed via the co-deposition method on inert... more
In this paper, an investigation of the properties of Cu and Cu/MgO nanoparticles (NPs) is presented. The NPs were obtained with gas-phase synthesis, and the MgO shells or matrices were formed via the co-deposition method on inert substrates. SEM and AFM were used to investigate the NP morphology on Si/SiOx, quartz, and HOPG. The Cu NPs revealed flattening of their shape, and when they were deposited on HOPG, diffusion and formation of small chains were observed. The embedding of Cu NPs in MgO was confirmed by TEM and EDX maps. XPS showed that Cu was in its metallic state, regardless of the presence of the surrounding MgO. UV–Vis revealed the presence of an intense localized surface plasmon resonance (LSPR) for Cu/MgO and for “bare” NPs. These results confirmed the role of MgO as a protective transparent medium for Cu, and the wavelength position of the LSPR in the Cu/MgO system was consistent with calculations. The wavelength position of the LSPR observed for “bare” and post-oxidize...
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The structure of Ag nanoparticles of different size, supported on the cerium oxide (111) surface, was investigated by X-ray absorption fine structure at the Ag K-edge. The results of the data analysis in the near and extended energy range... more
The structure of Ag nanoparticles of different size, supported on the cerium oxide (111) surface, was investigated by X-ray absorption fine structure at the Ag K-edge. The results of the data analysis in the near and extended energy range are interpreted with the help of the results obtained by X-ray photoelectron spectroscopy and scanning tunneling microscopy measurements and allow to obtain a detailed atomic scale description of the model system investigated. The Ag nanoparticles have an average size of a few tens of Å, which increases with increasing deposited Ag amount. The nanoparticles show a slight tendency to nucleate at the step edges between different cerium oxide layers and they have a face centered cubic structure with an Ag-Ag interatomic distance contracted by 3 – 4 % with respect to the bulk value. The interatomic distance contraction is mainly ascribed to dimensionality induced effects, while epitaxial effects have a minor role. The presence of Ag-O bonds at the inte...
1 Dipartimento di Scienze Fisiche Informatiche e Matematiche, Università degli Studi di Modena e Reggio Emilia, Via G. Campi 213/a, 41125 Modena, Italy 2 Istituto Nanoscienze, Consiglio Nazionale delle Ricerche, Via G. Campi 213/a, 41125... more
1 Dipartimento di Scienze Fisiche Informatiche e Matematiche, Università degli Studi di Modena e Reggio Emilia, Via G. Campi 213/a, 41125 Modena, Italy 2 Istituto Nanoscienze, Consiglio Nazionale delle Ricerche, Via G. Campi 213/a, 41125 Modena, Italy 3 European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble, France 4 Dipartimento di Fisica e Astronomia, Viale C. Berti Pichat 6/2, 40127 Bologna, Italy 5 Istituto Officina dei Materiali, Consiglio Nazionale delle Ricerche, Operative Group in Grenoble, c/o ESRF, BP 220, F-38043 Grenoble, France
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Real-time changes of Ce L3 XANES in bioactive glasses during H2O2 dissociation are related to changes in the Ce ion environment.
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LSPRs in Ag nanoparticles decay through a highly efficient charge injection into the 4f levels of the cerium oxide matrix.
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Research Interests: Engineering, Biochemistry, Evolutionary Biology, Neuroscience, Materials Science, and 15 moreTechnology, Molecular Biology, Computational Biology, Scanning Probe Microscopy, Ecology, Infectious Diseases, Medicine, Ev, PT, Surface Morphology, Kelvin Probe Force Microscopy, CHEMICAL SCIENCES, UHV, Redox, and Surface alloying
An accurate description of the structural and chemical modifications of cerium oxide nanoparticles (NPs) is mandatory for understanding their functionality in applications. In this work we investigate the relation between local atomic... more
An accurate description of the structural and chemical modifications of cerium oxide nanoparticles (NPs) is mandatory for understanding their functionality in applications. In this work we investigate the relation between local atomic structure, oxidation state, defectivity and size in cerium oxide NPs with variable diameter below 10 nm, using x-ray absorption fine structure analysis in the near and extended energy range. The NPs are prepared by physical methods under controlled conditions and analyzed in morphology and crystalline quality by high resolution transmission electron microscopy. We resolve here an important question on the local structure of cerium oxide NPs: we demonstrate a progressive contraction in the Ce-O interatomic distance with decreasing NP diameter and we relate the observed effect to the reduced dimensionality. The contraction is not significantly modified by inducing a 4%-6% higher Ce3+ concentration through thermal annealing in high vacuum. The consequence...
Research Interests: Mechanical Engineering, Bioengineering, Materials Science, Nanoparticle, Nanoparticles, and 12 moreTransmission Electron Microscopy, Nanotechnology, Medicine, Multidisciplinary, Mechanics of Materials, Crystal structure, Cerium Oxide, Oxidation State, Oxide, Cerium, extended x-ray absorption fine structure (EXAFS), and Electrical And Electronic Engineering
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Research Interests: Materials Engineering, Mechanical Engineering, Materials Science, Molecular Dynamics Simulations, Mechanics of Materials, and 13 moreCatalase, Materials Design, XPS, Ion, Cerium, Bioactive Glass, SEM EDS, Phosphate, X Ray Photoelectron Spectroscopy, Bioactivity, Second Language Composition, Redox, and Bioactive Glasses
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Research Interests: Engineering, Chemical Engineering, Biochemistry, Materials Science, Technology, and 15 moreComputational Biology, Biotechnology, Nanoparticle, Ecology, Nanotechnology, Medicine, Cerium Oxide, CO oxidation, CHEMICAL SCIENCES, Fine Structure Constant, Oxide, Cerium, American Chemical Society, Mixed Oxides, and Soot oxidation
Today most calculations of the electronic structure of solids are performed within the density functional theory. The approach relies on the existence of a model system of N-non interacting fermions, which has the same charge density as... more
Today most calculations of the electronic structure of solids are performed within the density functional theory. The approach relies on the existence of a model system of N-non interacting fermions, which has the same charge density as the actual interacting system.
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Research Interests: Condensed Matter Physics, Materials Science, Nanoparticle, Self Assembly, Scanning tunneling microscopy, and 12 moreThin Film, Grazing Incidence Small Angle X-Ray Scattering, Physical sciences, Nucleation, Dislocation, Dislocations, Wide Angle X-Ray Scattering, Cobalt, CHEMICAL SCIENCES, Self Organization, Room Temperature, and Cobalt Oxide
Research Interests: Physics, Condensed Matter Physics, Materials Science, Surfaces and Interfaces, Synchrotron Radiation, and 10 moreDensity Functional Theory, Thin Film, Physical sciences, Magnetic Properties, CHEMICAL SCIENCES, Magnetization, Ferromagnetism, Antiferromagnetism, Gamma-ray Spectroscopy, and non blocking I/O
Research Interests: Condensed Matter Physics, Materials Science, X ray absorption spectroscopy, Quantitative analysis, Thin Film, and 11 morePhysical sciences, Electronic properties, Multiple Scattering, CHEMICAL SCIENCES, Scattering, Quantitative Analysis, Atomic Structure, Lattice Constant, X ray Absorption, Quantitative Evaluation, and Physical Properties
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The modifications of the stoichiometry, morphology and surface structure of cerium oxide ultrathin films induced by thermal treatments under vacuum and oxygen partial pressure were studied using in situ X-ray photoemission spectroscopy,... more
The modifications of the stoichiometry, morphology and surface structure of cerium oxide ultrathin films induced by thermal treatments under vacuum and oxygen partial pressure were studied using in situ X-ray photoemission spectroscopy, scanning tunnelling microscopy and low energy electron diffraction. The effect of the film nominal thickness, heating temperature and heating time on the degree of reduction of the film was investigated. The reduction is more relevant on the film surface, where different ordered surface structures were observed at different degrees of reduction for very thin films. The obtained results are discussed taking into account the dimensionality of the oxide and the effects of the proximity of the Pt substrate. After reduction it was always possible to re-oxidize the films back to their original oxidation state by thermal treatment under oxygen-rich conditions.
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The ability of Ce-containing bioactive glasses to inhibit oxidative stress in terms of reduction of hydrogen peroxide, by mimicking the catalase enzyme activity is demonstrated here for the first time. The antioxidant properties of three... more
The ability of Ce-containing bioactive glasses to inhibit oxidative stress in terms of reduction of hydrogen peroxide, by mimicking the catalase enzyme activity is demonstrated here for the first time. The antioxidant properties of three bioactive glasses containing an increasing amount of CeO2 have been evaluated by following the degradation of hydrogen peroxide with time after immersion in H2O2 aqueous solutions with different concentration. XPS and UV-vis measurements allowed us to determine the Ce(3+)/Ce(4+) ratio in the bulk and on the glass surface, and to correlate it with the ability of the samples to show catalase mimetic activity. Interestingly, we have found that the bioactive glass with composition 23.2Na2O-25.7CaO-43.4SiO2-2.4P2O5-5.3CeO2 immersed in 0.1 M H2O2 aqueous solution is able to degrade 90% of it in 1 week. The reduction in bioactivity of the glasses with increasing CeO2 content is here rationalized in terms of a lower amount of phosphate groups available for the hydroxyapatite layer formation, after binding with cerium ions. In fact, classical molecular dynamics simulations revealed that the addition of CeO2 leads to the formation of cerium phosphate rich regions. The formation of an insoluble CePO4 crystalline phase is also observed by XRD analysis after thermal treatment of the glass samples.
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... P. Luches, A. di Bona, L. Marassi, L. Pasquali, S. Valeri, and S. Nannarone INFM and Dipartimento di Fisica, Universita` di Modena e Reggio ... as a function of the Fe coverage and assigned the magnetic changes to crystalline phase... more
... P. Luches, A. di Bona, L. Marassi, L. Pasquali, S. Valeri, and S. Nannarone INFM and Dipartimento di Fisica, Universita` di Modena e Reggio ... as a function of the Fe coverage and assigned the magnetic changes to crystalline phase transitions in the Fe film, calling for more ...
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Non-stoichiometric ceria nanoparticles (NPs) were obtained by a gas aggregation source with a magnetron and were mass-selected with a quadrupole mass filter. By varying magnetron power, Ar gas flow, and the length of the aggregation tube,... more
Non-stoichiometric ceria nanoparticles (NPs) were obtained by a gas aggregation source with a magnetron and were mass-selected with a quadrupole mass filter. By varying magnetron power, Ar gas flow, and the length of the aggregation tube, NPs with an average diameter of 6, 9, and 14 nm were synthesized and deposited onto a substrate, thus obtaining NP films. The morphology of the films was studied with scanning electron microscopy, while high resolution transmission electron microscopy was used to gain a deeper insight into the atomic structure of individual NPs. By using X-ray photoelectron spectroscopy we analyzed the degree of reduction of the NPs of different diameters, before and after thermal treatments in vacuum (reduction cycle) and in O2 atmosphere (oxidation cycle) at different temperatures. From this analysis we inferred that the size is an important parameter only at intermediate temperatures. As a comparison, we evaluated the reducibility of an ultra-thin ceria film with the same surface to volume ratio as the 9 nm diameter NPs film, observing that NPs are more reducible than the ceria film.