145 research outputs found
La frana di Pieve S. Stefano (Toscana orientale) e l'occlusione del F. Tevere del 1855.
No full textLa nota illustra i risultati di una ricerca storica relativa al movimento franoso di Pieve S. Stefano del 1855 che provocò l'occlusione del F. Tevere e l'allagamento del paese. I dati, tratti da documenti cartografici storici e dal rilevamento geologico-geomorfologico effettuato nell'area, costituiscono la prima fase di una ricerca che analizza l'interferenza tra i processi di dinamica fluviale dell'alveo e il corpo franoso, nell'ipotesi che la frana si fosse attivata in tempi recenti, con l'invaso artificiale di Montedoglio, situato solo qualche km più a valle, in pieno esercizio
A general [<SUP>18</SUP>F]AlF radiochemistry procedure on two automated synthesis platforms
No full textThe first general [18F]AIF automated radiolabelling procedure developed on the GE Tracerlab FX FN (Left) and Trasis AllInOne (Right) platforms.</p
Linear magnetic and alignment dichroism in Auger-photoelectron coincidence spectroscopy RID G-2497-2011 RID G-7348-2011
No full textAuger-photoelectron coincidence measurements for polarized targets are theoretically considered. We present a general expression for the cross section of sequential double photoionization of polarized atoms within the two-step model. Linear magnetic and alignment dichroism in coincidence experiments is discussed in more detail. For illustration, we made ab initio calculations based on the multiconfigurational Dirac-Fock theory for the 4d photoionization of atomic Sn followed by N-OO Auger decay
Spin selectivity by Auger-photoelectron coincidence spectroscopy
No full textThe M(3)M(4,5)M(4,5) Auger transition from a Cu(111) surface is studied using Angular Resolved Auger-PhotoElectron Coincidence Spectroscopy (AR-APECS). In the experiment two different geometrical configurations of the electron analyzers allow us to sample different emission angles of the ejected electrons leading to different weights of the singlet and triplet contributions in the studied transition. The experimental spectra are modeled within a two-step approach using the Cini theory for the closed band case so as to properly consider the spin-orbit interaction and the hole-hole correlation energy. Ingredients for the theory, like density of states, are obtained fully ab-initio in the framework of density functional theory by performing all-electron calculations. The obtained results confirm the recently discovered selectivity of AR-APECS in the final spin-state. RI Fratesi, Guido/A-4637-2010; Da Pieve, Fabiana /G-2497-201
Dichroic effects in Auger photoelectron coincidence spectroscopy of solids RID
No full textThe Sn M5N45N45 Auger spectrum from the (root 3 x root 3)R30 degrees-Sn/Ge(111) surface has been measured in coincidence with the corresponding 3d(5/2) photoelectron. By detecting this pair at appropriate emission angles, the contribution from spin-symmetric (triplet) and spin-antisymmetric (singlet) final states can be selectively enhanced or suppressed. This dichroic effect in the Auger photoelectron coincidence spectroscopy of solids provides a probe of the local valence electronic structure with element, chemical states, emission depth, and spin selectivity. The consequences and applications of this dichroic effect are discussed
Due soffitti di Francesco Savanni a Corticelle Pieve e in San Giorgio in Brescia
No full textVengono attribuite al pittore bresciano Francesco Savanni due volte affrescate, rispettivamente nella sacrestia della chiesa di san Giorgio in Brescia e nella parrocchiale di Corticelle Pieve nella Bassa bresciana. Qui il pittore lascia anche altre opere, in particolare un'incisione tratta da un dipinto murale della Vergine in adorazione del Bambino,conservata nella Pieve e ritenuta miracolosa
Immuno-PET Imaging of Tumour PD-L1 Expression in Glioblastoma
No full textThere is no established method to assess the PD-L1 expression in brain tumours. Therefore, we investigated the suitability of affibody molecule (ZPD-L1) radiolabelled with F-18 (Al18F) and Ga-68 to measure the expression of PD-L1 in xenograft mouse models of GBM. Mice bearing subcutaneous and orthotopic tumours were imaged 1 h post-radioconjugate administration. Ex vivo biodistribution studies and immunohistochemistry (IHC) staining were performed. Tumoural PD-L1 expression and CD4+/CD8+ tumour-infiltrating lymphocytes were evaluated in human GBM specimens. ZPD-L1 was radiolabelled with radiochemical yields of 32.2 ± 4.4% (F-18) and 73.3 ± 1.8% (Ga-68). The cell-associated radioactivity in vitro was consistent with PD-L1 expression levels assessed with flow cytometry. In vivo imaging demonstrated that 18F-AlF-NOTA-ZPD-L1 can distinguish between PD-L1 high-expressing tumours (U87-MGvIII) and PD-L1-negative ones (H292PD-L1Ko). The radioconjugate was quickly cleared from the blood and normal tissues, allowing for high-contrast images of brain tumours as early as 1 h post-injection. 68Ga-NOTA-ZPD-L1 showed heterogeneous and diffuse accumulation that corresponded to the extensively infiltrating GCGR-E55 tumours involving contiguous lobes of the brain. Lastly, 39% of analysed GBM patient samples showed PD-L1+ staining of tumour cells that was associated with elevated levels of CD4+ and CD8+ lymphocytes. Our results suggest that the investigated radioconjugates are very promising agents with the potential to facilitate the future design of treatment regimens for GBM patients
Evidence for the collapse of short-range magnetic order in CoO at the Neel temperature RID G-2497-2011
No full text""Auger-photoelectron coincidence spectroscopy is used for investigating the electronic properties of a CoO thin film above and below the magnetic transition temperature (T(N)). By using the dichroic effect in angle-resolved measurements, we identify and assign well-defined high-spin and low-spin structures in spite of the otherwise featureless Auger singles spectra, typically found for open-band systems. The disappearance of the dichroism for temperatures just above T(N) indicates a collapse of the surface short-range magnetic order, presumably due to a strongly reduced exchange field in the surface compared to that in the bulk. Copyright (C) EPLA, 2011"
Angular correlation between photoelectrons and Auger electrons within scattering theory RID G-2497-2011 RID G-7348-2011
No full textIn this paper we present a single-particle scattering approach for the angular correlation between a photoelectron and the subsequent Auger electron from atomic targets. This method is proposed as an alternative approach with respect to the usual density matrix formalism, since it is more convenient for extension to the solid state case. Such an extension is required by the great progress made in the field of coincidence spectroscopy in condensed matter systems. We derived a tensor expression for the cross section and an equivalent expression in terms of convenient angular functions has been treated for the case of linearly polarized light. Numerical calculations are performed for the L3M2,M-3(2),(3) transition in argon, in the single configuration Dirac-Fock scheme. Results are compared with experimental data for different final angular momentum states of the doubly charged ion and for different kinematical conditions
Efficient [<sup>18</sup>F]AlF Radiolabeling of Z<sub>HER3:8698</sub> Affibody Molecule for Imaging of HER3 Positive Tumors
No full textThe
human epidermal growth factor receptor 3 (HER3) is overexpressed
in several cancers, being linked to a more resistant phenotype and
hence leading to poor patient prognosis. Imaging HER3 is challenging
owing to the modest receptor number (<50000 receptors/cell) in
overexpressing cancer cells. Therefore, to image HER3 in vivo, high target affinity PET probes need to be developed. This work
describes two different [18F]AlF radiolabeling strategies
of the ZHER3:8698 affibody molecule specifically targeting
HER3. The one-pot radiolabeling of ZHER3:8698 performed
at 100 °C and using 1,4,7-triazanonane-1,4,7-triacetate (NOTA)
as chelator resulted in radiolabeled products with variable purity
attributed to radioconjugate thermolysis. An alternative approach
based on the inverse electron demand Diels–Alder (IEDDA) reaction
between a novel tetrazine functionalized 1,4,7-triazacyclononane-1,4-diacetate
(NODA) chelator and the trans-cyclooctene (TCO) functionalized
affibody molecule was also investigated. This method enabled the radiolabeling
of the protein at room temperature. The [18F]AlF-NOTA-ZHER3:8698 and [18F]AlF-NODA-ZHER3:8698 conjugates showed a specific uptake at 1 h after injection in high
HER3-expressing MCF-7 tumors of 4.36 ± 0.92% ID/g and 4.96 ±
0.65% ID/g, respectively. The current results are encouraging for
further investigation of [18F]AlF-NOTA-ZHER3:8698 as a HER3 imaging agent
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