VIRTUAL REALITY FOR HISTORICAL ARCHITECTURE

Abstract. This article shows a first step in the development of an immersive virtual tour of the Cathedral of Palermo, entering the fields of Digital Cultural Heritage and Edutainment. Its purpose is to help people to gain knowledge about the site, highlighting the complex stratifications that have characterized its history.The development of the project has been possible thanks to different phases of work: surveys were initially carried out by laser scanning, then assembled and processed to obtain the 3D model of the current state; at the same time, the model of reconstruction was processed in several phases, based on historical, archival and iconographic sources; both models were, later, …

Structural relaxation of E_gamma centers in amorphous silica

We report experimental evidence of the existence of two variants of the E' gamma centers induced in silica by gamma rays at room temperature. The two variants are distinguishable by the fine features of their line shapes in paramagnetic resonance spectra. These features suggest that the two E' gamma differ for their topology. We find a thermally induced interconversion between the centers with an activation energy of about 34 meV. Hints are also found for the existence of a structural configuration of minimum energy and of a metastable state.

MICROFLUIDIC PROCEDURE FOR FABRICATION OF HYALURONIC ACID BASED BIOMATERIALS

Metodologie da stampa a getto d'inchiostro per la fabbricazione di substrati SERS

Uno degli argomenti di maggiore interesse della Surface-enhanced Raman spectroscopy (SERS) è il controllo del posizionamento su superficie degli “hot spots” – le zone interstiziali fra aggregati di particelle metalliche che producono un aumento locale del segnale Raman. I substrati SERS consistono tipicamente in una matrice di hot-spots ad alta densità sui quali volumi macroscopici (>1 µL) di molecole di analita sono disperse. Questo approccio porta ad una alta invasività ed una distribuzione non uniforme dell’analita a causa dei flussi capillari. In questo lavoro, viene sviluppata una nuova piattaforma SERS realizzata da stampa a getto d’inchiostro2 in cui una miscela di un analita SERS…

Characterization of E'delta and triplet point defects in oxygen-deficient amorphous silicon dioxide

We report an experimental study by electron paramagnetic resonance (EPR) of gamma ray irradiation induced point defects in oxygen deficient amorphous SiO2 materials. We have found that three intrinsic (E'gamma, E'delta and triplet) and one extrinsic ([AlO4]0) paramagnetic centers are induced. All the paramagnetic defects but E'gamma center are found to reach a concentration limit value for doses above 10^3 kGy, suggesting a generation process from precursors. Isochronal thermal treatments of a sample irradiated at 10^3 kGy have shown that for T>500 K the concentrations of E'gamma and E'delta centers increase concomitantly to the decrease of [AlO4]0. This occurrence speaks for an hole tra…

Optical properties and photosensitivity of vacuum synthesized Ge-doped sol-gel amorphous SiO/sub 2/

We report optical and electron paramagnetic resonance investigations of gamma ray irradiation effects in sol-gel Ge-doped amorphous SiO/sub 2/. The studied materials have Ge-doping levels up to 10/sup 4/ molar part per million and were densified by two routes differing for the atmosphere: O/sub 2/+N/sub 2/ or vacuum. The obtained results evidence that irradiation affects matrix sites inducing paramagnetic defects. Furthermore, the comparison between the two densification procedures shows that vacuum atmosphere induces higher radiation sensitivity.

Artrite-Encefalite Caprina (CAEV) una patologia emergente nel territorio siciliano: programma volontario di eradicazione

L’Artrite-Encefalite Virale Caprina è una malattia infettiva segnalata per la prima volta nel 1974; l’agente causale è stato isolato solamente nel 1979: si tratta di un virus della famiglia Retroviridae, genere Lentivirus. Il virus si diffonde principalmente attraverso colostro, latte (durante la mungitura) e, in minor misura, attraverso sangue, saliva, espettorato, secrezioni vaginali. La malattia può evolvere in forma subdola e tende ad essere sottostimata negli allevamenti infetti. Le forme cliniche negli animali adulti si presentano sotto forma di artrite e/o mastite, mentre negli animali giovani, nei quali l’evidenza è ancora più rara, si osserva sintomatologia clinica riferibile ad en…

Self-cleaning materials active in the visible range based on porphyrin-sensitised titanium dioxide

In the last decades, nanostructured semiconductors played a central role in the material science scene because of their numerous applications spanning from renewable energy to organic/hybrid electronics up to photocatalysis. Titanium dioxide is one of the most used semiconductors because of its low cost, chemical stability, sustainability and versatility. Indeed, it is widely employed as photo-active or charge- transporting material in electronic devices, as photocatalyst in water de-pollution treatments etc.. Remarkably, one of the most interesting application of titanium dioxide consists of the protection and conservation of cultural heritages. Actually, TiO2 photocatalytic properties are…

Micrometer-size crystalline monolayer MoS2 domains obtained by sulfurization of molybdenum oxide ultrathin films

In this work, the formation of micrometer-size crystalline monolayer (1L) MoS2 flakes with triangular shape and a central multilayer core is obtained by the sulfurization at 800 °C of pre-deposited ultrathin MoOx films (1.2–1.8 nm) on c-sapphire substrates. The thickness uniformity, crystalline quality, doping and strain distribution in the MoS2 flakes as a function of the initial MoOx thickness was evaluated by micro-Raman (μR) mapping. The excellent crystalline quality of the triangular 1L-MoS2 flakes was confirmed by micro-photoluminescence (μPL) maps, showing a very intense peak at ∼1.85 eV, that decreases in the central part, as expected for multilayers MoS2. A biaxial strain of ∼0.38–…

Enhancement of antibiotic productions by plasma modified PLA electrospun membranes in Streptomyces coelicolor immobilized-cell cultivations

This study, encouraging the use of PLA membranes for actinomycetes cultivations, could unveil functional insights associated with antibiotic production and S. coelicolor cellimmobilization

Stability of sol-gel silica glass for CPV and ultraviolet LED applications

This paper concerns the characterization of silica glass obtained by a sol-gel technique as to its suitability in the terrestrial and space concentrated photovoltaic (CPV), and ultraviolet light emitting diode (UV LED) industrial sectors. The sol-gel material tested is produced by Evonik Industries and marketed under the brand name SAVOSIL™. The tests performed were aimed at determining the endurance of the material to radiation exposure and consist of exposure to gamma radiation and 355 nm UV laser light. In these tests the transmittance of the glass was measured before and after the exposure to the radiation to determine the effect of the radiation treatment. In the case of the test with …

MULTIFUNCTIONAL HYALURONIC ACID DERIVATIVE FOR EASY SCAFFOLD PROCESSING AND BIOLOGICAL FUNCTIONALIZATION

POLISACCARIDI FUNZIONALIZZATI CON PORZIONI ALCHILICHE: SINTESI, CARATTERIZZAZIONE REOLOGICA ED APPLICAZIONI BIOMEDICHE

Photocycle of point defects in highly- and weakly-germanium doped silica revealed by transient absorption measurements with femtosecond tunable pump.

AbstractWe report pump-probe transient absorption measurements addressing the photocycle of the Germanium lone pair center (GLPC) point defect with an unprecedented time resolution. The GLPC is a model point defect with a simple and well-understood electronic structure, highly relevant for several applications. Therefore, a full explanation of its photocycle is fundamental to understand the relaxation mechanisms of such molecular-like systems in solid state. The experiment, carried out exciting the sample resonantly with the ultraviolet (UV) GLPC absorption band peaked at 5.1 eV, gave us the possibility to follow the defect excitation-relaxation dynamics from the femto-picosecond to the nan…

INJECTABLE HYDROGEL BASED ON A NOVEL AMPHIPHILIC HYALURONIC ACID DERIVATIVE FOR CONTROLLED DRUG RELEASE

O2 trapping in silica nano-structures with high specific surfaces

We report an experimental investigation regarding the entrapping of O2 molecules inside various silica nano– structured systems having specific surfaces from 50 to 1000 m2/g. By recording Raman spectra and Near Infrared O2 emission we studied the O2 content per mass unit. Our data show that the internal voids of these nanostructured systems can trap O2 molecules diffusing from the surrounding air or from a pure O2 atmosphere, whereas the concentration of O2 that can be trapped in the silica near–surface layer is at least one order of magnitude lower. This low ability is consistently observed in non–porous and porous silica nanoparticles and in mesoporous silica systems. Furthermore, we obse…

Graphene oxide and Fumed silica graphene oxide nanocomposites modification by thermal treatments

In the present study we investigate post synthesis thermal treatments up to 400 °C of graphene oxide (GrO) prepared from commercial graphite and of GrO–silica nanocomposites prepared by a solution of commercial Fumed silica nanoparticles (average diameter 7 nm or 40 nm) and the GrO. The thermal treatments were carried out in air, vacuum or He atmosphere to highlight tunable changes. Two GrO batches with small differences in the D (~1350 cm–1) and G (~1580 cm–1) Raman bands have been employed to evaluate effects depending on preparation. Thermal effects have been monitored through the Raman spectroscopy focusing on D, G and 2D (2500–3500 cm–1) bands spectral ranges. The experiments evidenced…

SPRAY DRIED MICROPARTICLES OF A NEW HYALURONIC ACID DERIVATIVE FOR POTENTIAL BIO-INSTRUCTION OF STAMINAL CELLS

HYALURONIC ACID-BETA CYCLODEXTRINS HYDOGEL FOR THE TREATMENT OF SEVERE CORNEAL DISEASES

Plasma Functionalization of Multiwalled Carbon Nanotubes and Their Use in the Preparation of Nylon 6-Based Nanohybrids

The possibility to obtain carbon nanotubes (CNT)/polyamide 6 composites with excellent mechanical properties in a simple, industrially scalable way is investigated. Commercial CNTs are treated by plasma while changing some key parameters (exposure time, plasma power, type of gas) in order to optimize the process and to achieve a sufficient degree of functionalization. The treated samples are characterized by Fourier transform infrared spectroscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. The most interesting samples are selected to be used as reinforcing fillers, in different concentrations, in a polyamide 6 matrix. The mechanical tests show a dramatic increase of both tens…

Visible light active self-cleaning materials based on porphyrin-sensitised titanium dioxide

Starting from second half of last century, nanostructured semiconductors have had a crucial function in the material science because of their wide application field going from renewable energy to organic/hybrid electronics up to photocatalysis. Among those materials, titanium dioxide is probably the most used because of some important characteristics like the chemical/mechanical stability, environmental sustainability, its low cost and versatility. Indeed, it has been successfully employed as photo- and electro-active component in electronic devices as well as photocatalytic agent1 in water de-pollution application. Interestingly and importantly together, titanium dioxide may also be applie…

Nuovi biomateriali a struttura polisaccaridica per potenziali applicazioni in medicina rigenerativa

X-ray irradiation effects on a specific multistep Ge-doped fiber

International audience; The study of point defects generation in optical fibers plays an important role with regards to their use and application in different domains. Their design and elaboration processes (dopants type, concentration, refractive index profile, drawing conditions...) govern their responses and more generally their radiation hardness [1]. In this work we investigated, the influence of 10 keV X-ray irradiations on a set of specific germanosilicate optical fibers elaborated from the same preform at different drawing conditions. The germanium doping levels along the fiber core diameter was specifically designed to follow a two-step distribution in order to highlight the Ge-con…

Radiation Response of Ce-Doped Phosphosilicate Optical Fibers

International audience; We report an experimental study of the radiation effects on silica-based multimode optical fibers (OFs) either doped with Phosphorus or with Phosphorus and Cerium. Online Radiation-Induced-Absorption (RIA) measurements were performed in the UV-visible spectral domain under 10 keV X-ray Irradiation. Optical Absorption (OA) in the Near Infrared Region (NIR) and Electron Paramagnetic Resonance (EPR) measurements were also performed on γ-irradiated OFs.

Strain, doping and electronic transport of large area monolayer MoS2 exfoliated on gold and transferred to an insulating substrate

Gold-assisted mechanical exfoliation currently represents a promising method to separate ultra-large (cm-scale) transition metal dichalcogenides (TMDs) monolayers (1L) with excellent electronic and optical properties from the parent van der Waals (vdW) crystals. The strong interaction between $Au$ and chalcogen atoms is the key to achieve this nearly perfect 1L exfoliation yield. On the other hand, it may affect significantly the doping and strain of 1L TMDs in contact with Au. In this paper, we systematically investigated the morphology, strain, doping, and electrical properties of large area 1L $MoS_{2}$ exfoliated on ultra-flat $Au$ films ($0.16-0.21 nm$ roughness) and finally transferre…

New Insight on Medieval Painting in Sicily: The Virgin Hodegetria Panel in Monreale Cathedral (Palermo, Italy)

: The Virgin Hodegetria, located in the Cathedral of Santa Maria Nuova in Monreale, near Palermo (Italy), probably dating the first half of the 13th century, is one of the earliest examples of medieval panel painting in Sicily. A diagnostic campaign was carried out on the panel aiming to identify the constituting materials and the executive technique, as well as to assess the state of conservation for supporting the methodological choice of the restoration intervention. Both non invasive (X-ray radiography, digital microscope, multispectral imaging, ED-X-ray fluorescence) and micro-invasive (polarised light microscopy, ESEM-EDX, ATR-FTIR spectroscopy and micro-Raman spectroscopy) analyses w…