114 research outputs found

    Two seas for one great diversity: Checklist of the marine heterobranchia (Mollusca; Gastropoda) from the Salento Peninsula (South-East Italy)

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    The Salento peninsula is a portion of the Italian mainland separating two distinct Mediterranean basins, the Ionian and the Adriatic seas. Several authors have studied the marine Heterobranchia (Mollusca, Gastropoda) fauna composition living in the Ionian Sea, but to date further knowledge regarding this interesting group of mollusks is still needed. Recent studies have corroborated the peculiarity of the Mediterranean Sea showing high levels of endemism and cryptic diversity. On the other hand, marine sea slugs have been revealed to be important indicators of the marine ecosystem's health, due to their species-specific diet that consist of a vast variety of sessile and benthic invertebrates. A baseline study of the marine Heterobranchia diversity is therefore a necessary step to reveal the hidden diversity and to monitor the possible presence of alien species. The present study shows results from approximately 600 scientific dives carried out during a nine-year period in all of the main submarine habitats of the studied area, while accounting for the marine Heterobranchia from both the Ionian and Adriatic Seas. With this contribution, the list of marine Heterobranchia inhabiting the Salento Peninsula rises to 160. Furthermore, it also reports, for the first time, the presence of one alien species and three new records for Italian waters. Ecological notes and geographical distribution for each added species are provided together with animal iconography, consisting mainly of in situ photographs, for species identification

    A preliminary spectroscopic approach to evaluate the effectiveness of water-and silicone-based cleaning methods on historical varnished brass

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    Soiling deposition and wrong conservation practices are among the causes of the decay process that can affect the morphological, mechanical, and compositional features of the varnish, the most exposed layer of an artefact. In this perspective, the identification of the best cleaning practices is a priority. During the 18th century, scientific instruments of the highest quality were built, and peculiar varnishes were produced to confer protection and elegance to their metal elements. For this study, based on a historical recipe, we have reproduced a peculiar spirit varnish, enriched with natural resins and colorants, and we have applied on it a synthetic soiling mixture to simulate the aging conditions. We have then performed a non-invasive multi-analytical study to monitor the effectiveness of two water-based and a silicone-based, cleaning methods, namely, water in agarose, Tween 20 (3%) in agarose, and Velvesil Plus. The study includes colorimetry, Fourier transform infrared (FTIR) spectroscopy and X-ray fluorescence (XRF) mapping, coupled with chemometrics. Principal component analysis applied to FTIR spectral data has been demonstrated to be a powerful tool to enhance weak variations in the IR spectra, empowering the interpretation of cleaning effect versus the application time of each cleaning test

    Bimacrocyclic Effect in Anion Recognition by a Copper(II) Bicyclam Complex

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    The dicopper(II) complex of the bimacrocyclic ligand α,α′-bis(5,7-dimethyl-1,4,8,11-tetraazacyclotetradecan-6-yl)-o-xylene, 2, interacts with selected anions in dimethyl sulfoxide solution according to two different modes: (i) halides (Cl-, Br-, and I-) and N3- coordinate the two metal centers at the same time between the two macrocyclic subunits that face each other and (ii) anionic species that do not fit the bridging coordination mode (e.g., NCO-, SCN-, CH3COO-, NO3-, and H2PO4-) interact with copper(II) ions only at the "external" positions or their interaction is too weak to be detected. Occurrence of the bridging interaction is demonstrated by X-ray crystallographic studies performed on the adduct formed by [Cu2(2)]4+ with azide and by electron paramagnetic resonance investigation, as the anion coordination between the two copper(II) centers induces spin-spin coupling. Isothermal titration calorimetry experiments performed on [Cu2(2)]4+ and, for comparison, on [(5,7-dimethyl-6-benzyl-1,4,8,11-tetraazacyclotetradecane)copper(II)], representing the mononuclear analogue, allowed determination of thermodynamic parameters (log K, ΔH, and TΔS) associated with the considered complex/anion equilibria. Thermodynamic data showed that adducts formed by [Cu2(2)]4+ with halides and azide benefit from an extra stability that can be explained on the basis of the anion advantage of simultaneously binding the two metal centers, i.e., in terms of the bimacrocyclic effect

    Surface and interface treatments on wooden artefacts: Potentialities and limits of a non-invasive multi-technique study

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    Wooden artefacts embrace wide-ranging types of objects, like paintings on panel, sculptures, musical instruments, and furniture. Generally, in the manufacturing process of an artwork, wood is firstly treated with organic and inorganic materials to make it nonporous and morphologically homogeneous, and, at last, the surface treatment consists of varnishes or coatings applied with the aims of conferring aesthetic properties and protecting wood from biological growth and external degradation agents, as well as mechanical damage. In this work, different wooden mock-ups were prepared by varying some parameters: concentration of filler and pigment, respectively, in the ground and paint layers, thickness of the protective varnish coat, and sequence of the layers. The mock-ups were subsequently exposed to time-varying artificial aging processes. The multi-analytical non-invasive approach involved spectroscopic (reflection FT-IR, Raman, and X-ray fluorescence), tomographic (optical coherence tomography) and colorimetric techniques. Data were interpreted using both univariate and multivariate methods. The aim was to evaluate potential and limits of each non-invasive technique into the study of different stratigraphies of wooden artworks. This approach was supported by microscopic observations of cross-sections obtained from selected mock-ups. The methodological approach proposed here would add valuable technical know-how and information about the non-invasive techniques applied to the study of wooden artworks

    X-rays investigations for the characterization of two 17th century brass instruments from Nuremberg

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    A recent finding at the Castello Sforzesco in Milan of two brass natural horns from the end of the 17th century and assigned to the Haas family from Nuremberg brought to light new information about this class of objects. The instruments were heavily damaged, but their historical value was great. In this study, a multidisciplinary approach mainly based on non-invasive analytical techniques and including X-rays investigations (X-ray radiography, X-ray fluorescence and X-ray diffraction) was used. The present study was aimed at: i) pointing out the executive techniques for archaeometric purposes; ii) characterizing the morphological and the chemical features of materials; and iii) identifying and mapping the damages of the structure and the alterations of the surface

    Discovering the coating structure of historic bowed string instruments: an analytical campaign by SR-FTIR microspectroscopy

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    In many cases, the possibility to analyze a micro sample from an ancient bowed string instrument allows researchers to collect a wealth of information concerning materials used by the great Masters of violin-making and their construction procedures. In fact, the stratigraphic investigation may provide important information about (i) the treatments of the wood, normally involving proteinaceous materials and inorganic fillers such as carbonates, silicates, sulphates, (ii) composition of the different superimposed layers of varnish, and (iii) organic or inorganic pigments dispersed in the binders of the different superimposed layers of varnish [1]. In the present work, a set of four micro-samples - collected from well-preserved violins made by Antonio Stradivari, Francesco Ruggeri and Lorenzo Storioni - have been mounted in cross section and investigated throughout. The analytical approach has been developed on the embedded samples by means of Synchrotron Radiation (SR) FTIR microspectroscopy in reflection mode using a 15X objective, at the Chemical and Life Sciences branch of SISSI beamline (Elettra - Sincrotrone Trieste) [2]. Data have been collected in the MIR range in correspondence of each single layer of the stratigraphy, setting the lateral resolution in order to match the layer thickness (from few microns to tens of microns). A classification model has been constructed and validated to discriminate classes of materials according to the spectral information [3]. Preliminary results obtained from measurements performed by the micro-invasive SR-FTIR approach are elaborated and discussed, together with the analytical procedures, in order to characterize the features of the different samples

    Surface and interface treatments on wooden artefacts: Potentialities and limits of a non-invasive multi-technique study

    Get PDF
    Wooden artefacts embrace wide-ranging types of objects, like paintings on panel, sculptures, musical instruments, and furniture. Generally, in the manufacturing process of an artwork, wood is firstly treated with organic and inorganic materials to make it nonporous and morphologically homogeneous, and, at last, the surface treatment consists of varnishes or coatings applied with the aims of conferring aesthetic properties and protecting wood from biological growth and external degradation agents, as well as mechanical damage. In this work, different wooden mock-ups were prepared by varying some parameters: concentration of filler and pigment, respectively, in the ground and paint layers, thickness of the protective varnish coat, and sequence of the layers. The mock-ups were subsequently exposed to time-varying artificial aging processes. The multi-analytical non-invasive approach involved spectroscopic (reflection FT-IR, Raman, and X-ray fluorescence), tomographic (optical coherence tomography) and colorimetric techniques. Data were interpreted using both univariate and multivariate methods. The aim was to evaluate potential and limits of each non-invasive technique into the study of different stratigraphies of wooden artworks. This approach was supported by microscopic observations of cross-sections obtained from selected mock-ups. The methodological approach proposed here would add valuable technical know-how and information about the non-invasive techniques applied to the study of wooden artworks
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