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In this paper we report the result of a recent experiment of high resolution XANES (HERFD-XANES) which evidenced this modification suggesting that gold clusters with very similar size can have a modified electronic structure (the empty d-Density-of-states) when they are deposited on ceria and titania oxide

A novel research approach focused on innovative materials and methods to assure the long-term stability of bronze archaeological artefacts during exhibition and storage is reported. The work deals with the application of advanced analytical techniques and the development, characterisation and testing of materials and procedures for the conservation, protection and restoration of ancient Cu-based alloy artefacts. Our first aim was the selection of Cu-based alloy artefacts from different archaeological sites in Southern Italy with respect of chemical composition, metallurgical features and corrosion products. This step allowed the identification of the ancient alloys, the study of natural patinas and the identification of the involved degrading agents and mechanisms. Then the selection of long-term reliable, safe and environmentally friendly strategies for conservation was carried out. An original analytical approach based on the production of reference Cu-based alloys submitted to accelerated degradation tests was used to produce corroded samples for testing new materials with corrosion inhibiting properties.

The derivatisation of materials including iron, gold, and carbon by addition of diazonium salts is a reliable process to tune their interfacial interaction with the surrounding media. In this regard, the functionalisation of carbon nanostructures by diazonium chemistry is a versatile strategy to obtain soluble nanomaterials with degrees of functionalisation among the highest ever reported. Starting from these premises we have studied the functionalisation of multi-walled carbon nanotubes by addition of the aryl diazonium salts generated in situ by treatment of 4-methoxyaniline with isopentylnitrite. Following a thorough purification and characterisation protocol (UV-vis, TGA, ATR-IR, cyclic voltammetry, AFM and other surface analytical techniques), we have investigated the key parameters to obtain both functionalised multi-walled carbon nanotubes, where the amount of functional groups anchored to the carbon surface is less than a monolayer, and superfunctionalised carbon nanotubes, with a carbon nanotube core and a multilayered aryl coating. The results outlined provide the basis for the design and controlled processing of novel decorated carbon nanostructures that would be useful for a number of technological applications. © 2014 Elsevier Ltd. All rights reserved.

A scalable, single-step, synthetic approach for the manufacture of biocompatible, functionalized micro- and nanogels is presented. In particular, poly(N-vinyl pyrrolidone)-grafted-(aminopropyl)methacrylamide microgels and nanogels were generated through e-beam irradiation of PVP aqueous solutions in the presence of a primary amino-group-carrying monomer. Particles with different hydrodynamic diameters and surface charge densities were obtained at the variance of the irradiation conditions. Chemical structure was investigated by different spectroscopic techniques. Fluorescent variants were generated through fluorescein isothiocyanate attachment to the primary amino groups grafted to PVP, to both quantify the available functional groups for bioconjugation and follow nanogels localization in cell cultures. Finally, a model protein, bovine serum albumin, was conjugated to the nanogels to demonstrate the attachment of biologically relevant molecules for targeting purposes in drug delivery. The described approach provides a novel strategy to fabricate biohybrid nanogels with a very promising potential in nanomedicine.

Nanogels, or nanoscalar chemically crosslinked polymer networks, were generated by simultaneous crosslinking of Poly(N-vinyl pyrrolidone) (PVP) and grafting of acrylic acid (AA) monomer through e-beam irradiation of their aqueous solutions. The yield of the process is very high and no separation or complex purification procedures are required since no recourse to surfactants or organic solvents is made. The administered irradiation dose (40 kGy) imparts also sterility to the obtained nanogels in the form of aqueous dispersions. Control of particle size and size-distribution can be achieved by proper selection of the irradiation conditions. In particular, we obtained nanogel variants with average hydrodynamic diameters in the range 30 – 100 nm with PDI lower than 0.3 and negative surface charge density. Confirmation of the molecular architecture and detection of the surface composition have been sought through complementary spectroscopic techniques, such as FTIR and XPS. Preliminarily to any biological evaluation or bio-conjugation, absence of cytotoxicity was tested through MTT assay. Studies on nanogel viability thought cell compartments, carried out with fluorescent PVP nanogels variants incubated for different times in cell cultures and observed by confocal microscopy, showed cytoplasmic distribution of nanogels and preferential localization of around the nuclei during the first 7 hours and progressive disappearance during the following 17 hours. Nanogels secretion as waste products could be hypothesized. The availability of accessible carboxyl groups for subsequent facile bio-conjugation reactions makes this family of functional nanogels very promising for decoration with oligonucleotides. As a proof of concept, a fluorescent oligonucleotide semi-helix was conjugated through an amino group attached to the terminal 3’. The recognition ability of the conjugated forward semi-helix toward the reverse semi-helix was proved by spectrofluorimetric readings using a reverse oligo carrying a fluorescence quencher.

In this paper, the synthesis and characterization of novel amphiphilic graft copolymers based on an alpha,beta-poly(N-2-hydroxyethyl)-D, L-aspartamide (PHEA) backbone and D, L-polylactic acid (PLA) hydrophobic side chains are reported. These copolymers were obtained starting from PHEA-ethylenediamine (PHEA-EDA), which was functionalized with polysorbate 80 (PS(80)) and/or PLA in order to obtain the PHEA-EDA-PS(80)-PLA and PHEA-EDA-PLA samples, respectively. The degrees of derivatization, DD(PS80) and DD(PLA), of PHEA-EDA-PS80-PLA, calculated by (1)H-NMR, resulted in being 1.2 +/- 0.03 mol% and 0.54 +/- 0.05 mol%, respectively, while that of PHEA-EDA-PLA was found to be 0.60 +/- 0.05 mol%. Size exclusion chromatography (SEC) analysis confirmed the occurrence of derivatization, the molecular weight values being close to the theoretical ones. Polymeric micelles from PHEA-EDA-PLA and PHEA-EDA-PS(80)-PLA copolymers were obtained by using the dialysis method and were characterized in terms of mean size, zeta potential, critical aggregation concentration (CAC), and surface composition by x-ray photoelectron spectroscopy (XPS) analysis, which demonstrated the presence of PS(80) onto the PHEA-EDA-PS80-PLA micelle surface. In vitro experiments demonstrated that these systems had no cytotoxic effects on 16 HBE, Caco2, HuDe and K562 cell lines, and no haemolytic activity. Moreover, both PHEA-EDA-PS80-PLA and PHEA-EDA-PLA micelles were able to penetrate into Neuro2a cells and, in the case of PS(80) decorated micelles, to escape from phagocytosis by the J774 A1 macrophages.

Cobalt nickel bimetallic nanoparticles were synthesized by changing the sequence of the chemical reduction of Co(II) and Ni(II) ions confined in the core of bis(2-ethylhexyl)phosphate (2)., and Ni(DEHP)(2). The reduction was carried out by mixing, sequentially or contemporaneously, fixed amounts of n-heptane solution of Co(DEHP)2 and Ni(DEHP)2 micelles with a solution of sodium borohydride in ethanol at a fixed (reductant)/(total metal) molar ratio. This procedure involves the rapid formation of surfactant-coated nanoparticles, indicated as Co/Ni (Co after Ni), Ni/Co (Ni after Co), and Co + Ni (simultaneous), followed by their slow separation as nanostructures embedded in a sodium bis(2-ethylhexyl)phosphate matrix. The resulting composites, together with those obtained by reducing the n-heptane solutions of pure Co(DEHP)(2) or Ni(DEHP)(2), were characterized by XPS, EXAFS, WAXS, and SAXS. The data analysis confirms the presence of nanometer-sized surfactant-coated cobalt, nickel, and cobalt/nickel particles. As expected, the composition and internal structure of cobalt/nickel bimetallic nanoparticles are influenced by the preparation sequence as well as by the "chemical affinity" between the surfactant and the metal. However, some atomic-scale physicochemical processes play a subtle role in determining the structural features of bimetallic nanoparticles. Further effects due to the competition between nanoparticle growing process and surfactant adsorption at the nanoparticle surface were observed.

In this article, the synthesis of two amphiphilic polyaspartamide copolymers, useful to obtain polymeric nanoparticles without using surfactants or stabilizing agents, is described. These copolymers were obtained starting from α,β-poly-(N-2-hydroxyethyl)-dl-aspartamide (PHEA) by following a novel synthetic strategy. In particular, PHEA and its pegylated derivative (PHEA-PEG2000) were functionalized with poly(lactic acid) (PLA) through 1,1′-carbonyldiimidazole (CDI) activation to obtain PHEA–PLA and PHEA-PEG2000–PLA graft copolymers, respectively. These copolymers were properly purified and characterized by 1H-NMR, FT-IR, and Size Exclusion Chromatography (SEC) analyses, which confirmed that derivatization reactions occurred. Nanoparticles were obtained from PHEA–PLA and PHEA-PEG2000–PLA graft copolymers by using the high pressure homogenization-solvent evaporation method, avoiding the use of surfactants or stabilizing agents. Polymeric nanoparticles were characterized by dimensional analysis, before and after freeze-drying process, and Scanning Electron Microscopy (SEM). Zeta potential measurements and X-ray Photoelectron Spectroscopy (XPS) analysis demonstrated the presence of PEG and/or PHEA onto the PHEA-PEG2000–PLA and PHEA–PLA nanoparticle surface, respectively.

In the present work results on the degradation phenomena of stone materials in the Ancient Theatre of Taormina, one of the most important Greek–Roman monuments of Sicily, are reported. Artificial stone materials in different conservation conditions were investigated. Samples of salt efflorescences from brick walls and degraded setting mortars were taken from the open gallery in “summa cavea”. The chemical, physical and structural characterization was performed by means of X-Ray Photoelectron Spectroscopy (XPS), X-Ray Diffraction (XRD) and X-Ray Fluorescence (XRF), both in situ and ex situ. Results showed that the deterioration of stone materials is due to the aggressive action of the environment agents. Soluble salts, such as chlorides, sulphates and nitrates, were found in efflorescence samples. Mortars were affected by a decomposition process induced by sulphates’ attack.

A systematic investigation of the original materials and the degradation phenomena induced by soluble salts on the wall matrix and on the graffiti of the Inquisition jails of Chiaramonte Palace in Palermo (Italy) was carried out. Built in the XIV century, Chiaramonte Palace was used as Inquisition court during the XV–XVI centuries. The ancient graffiti, recently discovered, represent a unique historical witness of the prisoners that lived during that terrible period. In order to study the nature, the amount and the distribution of the salts in the masonry, stone materials sampled at different depth from the wall matrix and saline efflorescences were analysed. Different physical techniques were used, such as X-ray Photoelectron Spectroscopy, X-ray Fluorescence, Laser Induced Breakdown Spectroscopy, X-ray Diffraction and Ionic Chromatography. Results of the chemical and physical characterisation showed that the main cause of the degradation of graffiti and wall paintings was the presence of soluble salts, such as nitrates, chlorides and sulphates. Traces of oxalates, coming from a previous conservation treatment, were also found. The results obtained by the stratigraphical characterisation of soluble salts in the wall matrix can be used to recommend a procedure based on air humidification at high relative humidity values in order to avoid salt crystallisation and to prevent the crumbling process of the graffiti.

The preparation and characterization of surface-PE Gylated polymeric nanoparticles are described. These systems were obtained by UV irradiation of PHM and PHM-PEG(2000) as an inverse microemulsion, using an aqueous solution of the PHM/PHM-PEG(2000) copolymer mixture as the internal phase and triacetin saturated with water as the external phase, and characterized by dimensional analysis, zeta-potential measurements and XPS. in vitro biological tests demonstrated their cell compatibility and their ability to escape from phagocytosis. Rivastigmine was encapsulated into the nanoparticle structure and drug-release profiles from loaded samples were investigated in PBS at pH = 7.4 and human plasma.

In un recente studio condotto mediante Rilassometria NMR del nucleo 1H su legni moderni stagionati è stato mostrato che è possibile separare la curva di rilassamento della componente longitudinale della magnetizzazione nucleare dei nuclei 1H meno mobili (componente “solida”), attribuibili alle macromolecole, da quella dei nuclei a maggior mobilità (componente “liquida”), attribuibili all’acqua. Oltre a permettere di verificare la proporzionalità diretta tra ampiezza della componente liquida del segnale e massa d’acqua, l’analisi delle curve di rilassamento mediante distribuzioni quasi-continue del tempo di rilassamento longitudinale T1 permette di classificare le essenze lignee esaminate, mettendo in evidenza variazioni regolari di tale tempo nel passare da latifoglie a conifere. Alcune regolarità osservate possono essere giustificate assumendo un modello di scambio a due siti, con un tempo di scambio solido-liquido di qualche decina di ms. La stessa analisi, condotta su campioni di legno della statua di San Nicola di Mira (XVI secolo) recentemente restaurata e collocata presso il Museo Diocesano di Palermo, mostra che anche per il legno antico, sebbene fortemente degradato, valgono le stesse regolarità, ma con valori per i tempi di rilassamento e per il tempo di scambio solido-liquido che sono circa la metà di quelli osservati per il legno moderno. Si avanza l’ipotesi che questa accelerazione nei processi di rilassamento e di scambio sia associabile all’aumento del contributo paramagnetico, legato alla presenza di radicali liberi nel legno degradato, messo in evidenza in uno studio parallelo mediante EPR. Per il legno antico trattato non valgono le regolarità osservate per il legno non trattato, sia esso moderno od antico. Le regolarità riscontrate suggeriscono che la Rilassometria NMR possa essere utilizzata in futuro per analisi non distruttive volte alla classificazione delle essenze ed alla diagnosi del degrado di legni di interesse storico-artistico-archeologico.

Qui di seguito viene illustrato il progetto scientifico ATENA, svolto presso l'Istituto per lo Studio dei Materiali Nanostrutturati (ISMN) del Consiglio Nazionale delle Ricerche (CNR) e co-finanziato dal MIUR con Decreto Direttoriale 9-10-2002, n. 1105/2002. Il progetto si propone di applicare avanzate tecniche diagnostiche strumentali al fine di acquisire la dettagliata conoscenza microchimica e microstrutturale di manufatti metallici e ceramici antichi, di definirne il meccanismo di alterazione e/o degrado e di progettare, sintetizzare e validare opportuni prodotti e formulazioni per il restauro conservativo di tali manufatti. Le conoscenze acquisite sono utilizzabili anche per il recupero delle antiche tecniche di produzione e per una loro possibile riproposizione sia nel campo del restauro integrativo che nell'ambito dell'artigianato culturale.

The production of reference Cu-based alloys is the first step of an original experimental protocol to be used in the field of conservation and restoration of metal artefacts. The production of these synthetic alloys has a double value. They can be used both as suitable substitutes of unique archaeological pieces for testing new materials and methods for conservation, and as guidelines for contemporary metal production. We report on a research activity focused on the recovery of the ancient production techniques from the investigation of archaeological copper-based artefacts. The chemical, physical and metallurgical characterization of several Cu-based artefacts, found in different Italian archaological sites, was carried out by bulk and surface techniques in order to investigate the nature and properties of the metallic substrates and the corrosion products. Chemical and metallurgial formulations of the ancient archaeological alloys were obtained by data analyses. On the basis of these results, a set of Cu-based alloys with different chemical compositions and metallurgical features was produced. The chemical and physical characterization showed that these modern Cu-based alloys strictly resemble the ancient ones constituting the archaeological artefacts from a chemical, micro-morphological and metallurgical point of view.

Nanostructured perovskite-type Sr1−aCeaFeO3−x, (0⩽a

Gold nanoparticles supported on different oxides (SiO2, CeO2 and TiO2) were prepared by the SMAD (solvated metal atom dispersion) and deposition–precipitation (DP) techniques. The physical and chemical characterization of the catalysts was performed by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) and the catalytic activity was tested during the reaction of low temperature CO oxidation. The structural and surface analyses evidenced the presence of small gold crystallites (cluster size ∼2–5 nm) in all the SMAD-prepared samples and oxidized gold species in the case of the DP catalysts. A different surface distribution of ionic gold species was found on the different supports. By comparing the catalytic activities of the samples, the presence of Au+1 species seems to be the main requisite for the achievement of the highest CO conversion at the lowest temperature. The higher activity of Au/CeO2(DP) catalysts at T ≈ 250 K can be ascribed to a better stabilization of the AuO− species by the cerium oxide. Nanosized metallic gold particles exhibit a worse catalytic performance, both on ‘reducible’ and ‘inert’ supports, being significantly active only in the temperature range: 400–600 K. Copyright © 2006 John Wiley & Sons, Ltd.

Nanostructured gold catalysts supported on CeO2 and SiO2 were prepared by the deposition–precipitation (DP) and the solvated metal atom dispersion (SMAD) techniques. The structural and electronic properties of the catalysts were investigated by X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS) and X-ray photoelectron spectroscopy (XPS). Gold was found as small metal nanoparticles (cluster size ∼2 nm) in the SMAD-prepared samples and in ionic state in the DP catalysts. The catalytic activity of the samples was tested in the reaction of low temperature CO oxidation. Gold nanosized particles in a pure metallic state exhibited a worse catalytic performance, both on ceria and silica. The presence of non-metallic Au species seems to be the main requisite for the achievement of the highest CO conversion at the lowest temperature. The higher activity of the Au/CeO2 (DP) sample with respect to the Au/SiO2 (DP) catalyst can be ascribed to a better stabilization of the Au+1 ions, probably as AuO- species, by the cerium oxide.