281 research outputs found
Appendice III. Misure dei rapporti isotopici di piombo su monete di Ybshm/Ebusus e su alcune imitazioni di area campana
No full textGeographical discrimination of saffron (Crocus sativus L.) using ICP-MS elemental data and class modeling of PDO Zafferano dell’Aquila produced in Abruzzo (Italy)
No full textPDO (protected designation of origin) Zafferano dell’Aquila (AQ), Iranian (IR), and commercial (CS) saffron samples were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The ICP-MS data of 30 elements were handled by unsupervised (principal component analysis (PCA)) and supervised (linear discriminant analysis (LDA)) multivariate statistical methods to identify a subset of discriminant variables useful for geographical classification. Moreover, class modeling of AQ saffron was performed by both UNEQ (unequal disperses classes) and SIMCA (soft independent modeling of class analogy) methods. A good differentiation of the AQ, IR, and CS samples was obtained by the LDA based on four selected elements: Sr, Ca, Mo, and Fe. A UNEQ class model for the PDO AQ saffron based on the above four elements provided 100% sensitivity (all authentic AQ saffron were accepted) and 100% specificity (all IR and CS were rejected), while slightly worse results were obtained using the SIMCA (89% sensitivity and 96% specificity)
Characterization of Broad Energy GermaniumDetector (BEGe) as a candidate for the GERDA Experiment
No full textBroad Energy Germanium detectors (BEGe) offer an excellent discrimination power for pulse shape analysis of signals induced by interactions in the active volume of the detector. Such a feature makes them potential candidates for double beta decay experiments. In fact, analysis of time development of pulses allows to reject multi sites events (MSE) for which ionization takes place in more than one position, from single-site events (SSE) that release all the energy within a small volume. Double beta decay events, characterized by the interactions of the two electrons emitted, belong to the latter category of events, while MSE, mainly γ-rays interactions, constitute the background that has to be rejected. BEGe are currently considered as potential candidates the Phase II of GERDA experiment, looking for 76Ge double beta decay at the INFN Underground Gran Sasso National Laboratory (LNGS). Characterization of a commercial BEGe from Canberra is presented together with the results of the pulse shape analysis. Moreover, a full detector model (electric field and pulse generation), developed to understand the pulse shape discrimination power of the detector and validated with dedicated measurements, is presented and discussed
A multi-channel digital acquisition system for Ge spectroscopy in the GERDA experiment
No full textWe developed a multi-channel digital acquisition (DAQ) system, able to operate in connection to Germanium-based detectors and state-of-the-art charge sensitive preamplifiers. The DAQ system is composed of up to 6 front-end NIM modules, each one with 4 free running analog to digital converters (100 MHz, 14 bits) and up to 6 custom PCI based receiver boards inside a single personal computer (PC). We also implemented a comprehensive graphical user interface on the user PC and a digital triggering algorithm inside the DAQ system by means of programmable logic devices (FPGA) and a suitable global slow control for the whole system. The performances of the DAQ system in terms of energy resolution, sustained data transfer rate, digital trigger sensitivity, etc. are all within the specifications of the GERDA experiment for Phase-I
Standardizzazione di un protocollo per saggi di tossicità acuta con larve di spigola (Dicentrarchus labrax, L.1758): II esercizio di interconfronto.
No full textCharacterisation of element profile changes induced by long-term dietary supplementation of zinc in the brain and cerebellum of 3xTg-AD mice by alternated cool and normal plasma ICP-MS
No full textMetal dyshomeostasis plays a crucial role in promoting several neurodegenerative diseases including Alzheimer's disease (AD), a condition that has been linked to deregulation of brain levels of Al, Fe, Mn, Cu, and Zn. Thus, quantitative multi-element profiling of brain tissues from AD models can be of great value in assessing the pathogenic role of metals as well as the value of therapeutic interventions aimed at restoring metal homeostasis in the brain. In this study, we employed low resolution inductively coupled plasma mass spectrometry (ICP-MS) to evaluate levels of ultra-trace, trace, and major elements in brains and cerebella of 3xTg-AD mice, a well characterized transgenic (Tg) AD model. This method is based on alternated cool and hot plasma ICP-MS. The essay fulfilled analytical requirements for the quantification of 14 elements in the Central Nervous System (CNS) of our Tg model. Quantification of Li, Al, Cr, and Co, a procedure that requires a pre-concentration step, was validated by high resolution ICP-MS. Changes in element profiles occurring in 3xTg-AD mice were compared to the ones observed in wild type (WT) mice. We also investigated variations in element profiles in 3xTg-AD mice receiving a long-term (17 months) dietary supplementation of Zn. Our data indicate that, compared to WT animals, 3xTg-AD mice displayed signs of altered brain metal homeostasis. We also found that long-term Zn administration promoted decreased brain levels of some metals (K, Ca, and Fe) and restored levels of Al, Cr, and Co to values found in WT mice
Precise lead isotope ratios measurements on Ebusus coins and on some Campanian imitations
No full textCoin finds in Pompeii are characterised by a large amount of specimens from Ebusus e Massalia and by Campanian coins that imitate the types of those foreign productions.
Using mass spectrometry it was possible to get information useful to understand in a better way the differences between original issue and imitations; furthermore this study highlighted socio-economic reasons: on one hand, the arrival of a great deal of Ebusitan and Massalian coins in the ancient city, on the other, the need to mint imitation coins in ager vesuvianus.
Data about the supply of different metals used to obtain alloys were identified and -also thanks to historical reflection- it can be considered important to discover connections between Ebusitan coinage and the people that introduced those foreign specimens and the Campanian imitations
Cryogenic readout techniques for Germanium detectors
No full textHigh Purity Germanium detectors are used in many applications, from nuclear and astro-particle physics, to homeland security or environment protection. Although quite standard configurations are often used, with cryostats, charge sensitive amplifiers and analog or digital acquisition systems all commercially available, it might be the case that a few specific applications, e.g. satellites, portable devices, cryogenic physics experiments, etc. also require the development of a few additional or complementary techniques. An interesting case is for sure GERDA, the Germanium Detector Array experiment, searching for neutrino-less double beta decay of 76Ge at the Gran Sasso National Laboratory of INFN - Italy. In GERDA the entire detector array, composed of semi-coaxial and BEGe naked crystals, is operated suspended inside a cryostat filled with liquid argon, that acts not only as cooling medium and but also as an active shield, thanks to its scintillation properties. These peculiar circumstances, together with the additional requirement of a very low radioactive background from all the materials adjacent to the detectors, clearly introduce significant constraints on the design of the Ge front-end readout electronics. All the Ge readout solutions developed within the framework of the GERDA collaboration, for both Phase I and Phase II, will be briefly reviewed, with their relative strength and weakness compared together and with respect to ideal Ge readout. Finally, the digital processing techniques developed by the GERDA collaboration for energy estimation of Ge detector signals will be recalled
Preparation of wrapped carbon nanotubes poly(4-vinylpyridine)/MTO based heterogeneous catalysts for the oxidative desulfurization (ODS) of model and synthetic diesel fuel
No full textThe preparation of novel wrapped carbon nanotubes poly(4-vinylpyridine)/methyl trioxorhenium based heterogeneous catalysts has been reported by two different procedures: a) the wrapping by grinding of multiwall carbon nanotubes with pre-formed adducts, respectively, [poly(4-vinylpyridine)·methyltrioxorhenium] or [poly(4-vinylpyridine)-N-oxide·methyltrioxorhenium] and, b) the loading of methyltrioxorhenium on previously wrapped multiwall carbon nanotubes with poly(4-vinylpyridine) and poly(4-vinylpyridine)-N-oxide resins. The novel catalysts were characterized by SEM, TEM, ICP-MS and XPS analyses. Both types of catalysts were efficient systems in the oxidation of recalcitrant aromatic sulfur derivatives with H2O2, as representative models of oxidative desulfurization processes, affording the corresponding sulfones with yields ranging from moderate to quantitative. The oxidation of a complex model fuel oil and of synthetic diesel fuel, under optimal experimental conditions, is also reported. The performance of novel catalysts was dependent on the specific procedure applied for the immobilization of the active species, and was more efficient for both model oil and synthetic diesel fuel samples (with quantitative conversions and selectivities to the corresponding sulfones), than for isolated substrates
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