Geochronological study of zircons from continental crust rocks in the Frido Unit (southern Apennines)

Zircon crystals have been separated from gneisses and metagranitoids of the Pollino area (southern Apennines) in order to unravel the origin of these crustal slices within the ophiolite-bearing Frido Unit. The morphology of the zircon has been investigated by SEM, and the internal structure was revealed by cathodoluminescence. Data obtained by U/Pb dating have been used to deduce the age and significance of the different crystallization stages of zircon, connected to the evolutionary stages of the continental crust (Late Paleozoic\u2013Early Mesozoic). Zircons in gneisses are characterized by inherited cores of magmatic origin, bordered by metamorphic rims. Inherited zircons generally show Paleoproterozoic to Ordovician ages, indicating the provenance of the sedimentary protolith from different sources. The exclusive presence of Late Neoproterozoic zircon cores in leucocratic gneisses may suggest a different magmatic source possibly connected to Pan-African events. Late Carboniferous\u2013Early Permian ages are found mainly in zircon rims of metamorphic origin. These are similar to the emplacement ages of protolith of the metagranites in the middle crust portion. Late Carboniferous\u2013Early Permian metamorphism and magmatism testify the extensional collapse of the Hercynian belt, recorded in European, particularly, in the Corsica\u2013Sardinia block and in Calabria. Late Permian\u2013Triassic ages have been detected in zircon rims from gneisses and metagranitoids. These younger ages appear related to deformation and emplacement of albite\u2013quartz veins in both lithologies, and are related to an extensional episode predating the Middle Triassic to Middle Jurassic rifting in the Tethyan domain, followed by Middle to Late Jurassic spreading

Funghi ipogei della basilicata. III Contributo.

Le tavole a colori sono state pubblicate alle pagine 156-16

Funghi ipogei della Basilicata. III Contributo

Viene segnalata la presenza in Basilicata dei seguenti funghi ipogei: Balsamia vulgaris, Genea fragrans, G. hispidula, Pachyphloeus citrinus, P.ligericus; Hymenogaster lycoperdineus. Con questi 6 nuovi ritrovamenti, sale a 35 il n. degli ipogei segnalati fino all'aprile 2004 nella regione

A capillary zone electrophoretic method for size characterization of gold nanoparticles

The unusual size dependent chemical and physical properties make nanoparticles attractive for quite different fields of applications1. The characterization of size distribution of solution grown nanoparticles is usually performed by dynamic light scattering and transmission electron microscopy2 (TEM). A method here is proposed for the separation of gold colloid standards, with core diameters ranging from 5 to 20 nm, using free solution capillary zone electrophoresis. The size characterization was possible by adding to the buffer poly(sodium 4-styrenesulfonate) which infers an “electrosteric” stabilization3 to colloids, exalting the difference in their electrophoretic mobilities. Applying a potential step for separation, a significant improvement was provided in terms of resolution between different sized colloids whose migration time varied linearly with particle diameter. A comparison with the size distribution derived by TEM allowed to assess that the electrophoretic profile is representative of the effective heterogeneity in size of each colloid sample. The practical utility of the method was demonstrated by measuring the size distribution of a home synthesized gold colloid which was in good agreement with the profile derived by TEM. 1. Daniel, M.C.; Astruc, D. Chem. Rev. 2004, 104, 293-346. 2. Henglein, A. J. Phys. Chem. 1993, 97, 5457-5471. 3. Pugh, T.L.; Heller, W. J. Polym. Sci. 1960, 47, 219-227

Pulsed electrochemical deposition of nickel oxides on multi-walled carbon nanotubes from EDTA alkaline solutions: a SEM, XPS, and voltammetric characterization

A study regarding the electrodeposition of nickel oxide particles on the activated multi-walled carbon nanotubes from 2 M NaOH solution containing Ni(NO3)2 and EDTA was carried out. The electrodeposition process was carried out using an optimized double-pulse sequence of potentials: E1 = â\u88\u920.2 V vs. SCE (t1 = 0.3 s) and E2 = 0.7 V vs. SCE (t2 = 0.03 s). Spectroscopic XPS investigations and SEM analysis were used in order to characterize the surface and morphology of the studied modified electrode. Cyclic voltammetry and chronoamperometry were used in order to evaluate the electrochemical/amperometric performance of the GC/MWCNT-Ni electrode toward the oxidation of some aliphatic alcohols in strong alkaline medium

Formation of Titanium Carbide (TiC) and TiC@C core-shell nanostructures by ultra-short laser ablation of titanium carbide and metallic titanium in liquid

Laser ablation of bulk target in liquid allows to obtain stable nanoparticles and nanostructures, also in metastable phases, limiting the use of hazardous reagents and extreme reaction conditions. Titanium carbide (TiC) is a ceramic compound with several technological applications ranging from biocompatible materials to wear resistant coatings. The possibility to obtain core/shell structures expands its range of application due to the ability of modify the surface properties of the core ceramic material. TiC and metallic titanium targets have been ablated by means of an ultra-short laser source in different liquid media (water, acetone, n-hexane and toluene). The obtained colloidal solutions have been characterized by TEM, XRD and micro-Raman analysis. In all the used experimental conditions TiC nanoparticles have been produced. During water and acetone mediated ablations, the oxidation of titanium has been observed, whereas by using oxygen free solvents, such as n-hexane and toluene, core/shell TiC nanoparticles embedded in amorphous and graphitic carbon shell, respectively, have been obtained

Studi ulteriori sui funghi ipogei della Puglia

Con il reperimento di Tuber fulgens, Genea hispidula, Balsamia vulgaris e Choiromyces meandriformis (Ascomycetes);e Melanogaster variegatus, Rhizopogon vulgaris, Hymenogaster lycoperdineus, H. populetorum, H. vulgaris e Radiigera atrogleba (Basidiomycetes), sale a 22 il n° dei funghi ipogei finora segnalati in Puglia

Rutile microtubes assembly from nanostructures obtained by ultra-short laser ablation of titanium in liquid

Pulsed laser ablation of a titanium target in water was performed by an ultra-short laser source (Ti:sapphire, @=800nm, 1kHz, 100fs). The obtained structures were characterized by Atomic Force Microscopy, Scanning Electron Microscopy, X-Ray Photoelectron Spectroscopy, micro-Raman spectroscopy and X-ray Diffraction, revealing the presence of non-stoichiometric titanium oxide nanoparticles with a certain amount of crystalline rutile phase. Upon remaining in water the ablated species, the formation of a lamellar phase has been observed. This lamellar phase rolls up to microtubes by remaining in water for a month, through a self-assembling process. The formed microtubes, with an inner diameter of about 2 um and an outer diameter of 4 um are characterized by a smooth interior surface and aggregation of nanoparticles on the outer surface