Search results for "Proton"
showing 10 items of 5886 documents
Analisi di sicurezza nella procedura di protonterapia oculare applicata presso i Laboratori del Sud dell’INFN di Catania
2017
A partire dal 2002, l’Azienda Ospedaliera Universitaria “Policlinico Vittorio Emanuele” di Catania ha effettuato il trattamento di circa 350 pazienti affetti da neoplasie oculari mediante fasci di protoni prodotti con il ciclotrone disponibile presso i Laboratori nazionali del Sud (LNS). Tale impianto viene utilizzato per attività di ricerca nell’ambito della fisica sperimentale, per cui è stato necessario modificare le caratteristiche del fascio, rendendolo idoneo alle applicazioni cliniche. Il lavoro di ricerca ha riguardato lo svolgimento della analisi del rischio volto ad individuare possibili fallimenti nelle procedure adottate per il trattamento del paziente sottoposto a cicli di prot…
Influence of heteropolyacid in enhancing proton conductivity of chitosan membranes for H2/O2 Fuel Cells
2016
To promote Proton Exchange Membrane Fuel Cells (PEMFCs) commercialization, large research effort has been devoted in developing new polymer electrolytes that can replace the usually employed proton conductors, e.g. Nafion®, with other membranes of comparable performances but lower cost. Chitosan (CS)-based membrane electrolyte is currently studied as alternative candidate for PEMFC application. Several works have shown that Heteropolyacids (HPAs) can be used to prepare Chitosan polyelectrolytes (PECs) to be employed as proton exchange membrane in low temperature fuel cell. In previous works [1-3] we have shown that CS/PTA membranes, prepared using alumina porous medium for the slow release …
Bipolar membrane reverse electrodialysis for the sustainable recovery of energy from pH gradients of industrial wastewater: Performance prediction by…
2021
Abstract The theoretical energy density extractable from acidic and alkaline solutions is higher than 20 kWh m−3 of single solution when mixing 1 M concentrated streams. Therefore, acidic and alkaline industrial wastewater have a huge potential for the recovery of energy. To this purpose, bipolar membrane reverse electrodialysis (BMRED) is an interesting, yet poorly studied technology for the conversion of the mixing entropy of solutions at different pH into electricity. Although it shows promising performance, only few works have been presented in the literature so far, and no comprehensive models have been developed yet. This work presents a mathematical multi-scale model based on a semi-…
Random Quasi-Phae-Matching in Tantalatio di Litio: origine del fenomeno, confronto tra propagazione bulk e guidata.
2011
We observe second harmonic generation via random quasi phase matching in a 1.5μm periodically poled lithium tantalate. The presence of a slab waveguides allows the comparison between bulk and guided wave configurations.
Radial Basis Function Interpolation for Referenceless Thermometry Enhancement
2015
MRgFUS (Magnetic Resonance guided Focused UltraSound) is a new and non-invasive technique to treat different diseases in the oncology field, that uses Focused Ultrasound (FUS) to induce necrosis in the lesion. Temperature change measurements during ultrasound thermo-therapies can be performed through magnetic resonance monitoring by using Proton Resonance Frequency (PRF) thermometry. It measures the phase variation resulting from the temperature-dependent changes in resonance frequency by subtracting one phase baseline image from actual phase. Referenceless thermometry aims to re-duce artefacts caused by tissue motion and frequency drift, fitting the back-ground phase outside the heated reg…
IPOMAGNESEMIA GRAVE CORRELATA ALL’ASSUNZIONE DI INIBITORE DI POMPA PROTONICA
2017
Gli inibitori di pompa protonica (IPP) sono tra i farmaci più frequentemente assunti nella popolazione anziana, spesso cronicamente, anche per indicazioni non sempre giustificate. Sebbene siano farmaci ben tollerati, emergono sempre nuove e frequenti reazioni avverse. In particolare, negli ultimi anni, sono stati riportati vari case-report di ipomagnesemia insorta dopo terapia prolungata con IPP. Tuttavia, ad oggi, non è stato di-mostrato il meccanismo fisiopatologico con cui queste molecole possono indurre tale disionia. Il magnesio è il secondo catione più abbondante nella cellula e svolge ruoli chiave in molti processi intracellulari. La sua omeostasi è garantita dall’equilibrio tra l’as…
Laboratory evidence for proton energization by collisionless shock surfing
2021
Charged particles can be accelerated to high energies by collisionless shock waves in astrophysical environments, such as supernova remnants. By interacting with the magnetized ambient medium, these shocks can transfer energy to particles. Despite increasing efforts in the characterization of these shocks from satellite measurements at Earth’s bow shock as well as powerful numerical simulations, the underlying acceleration mechanism or a combination thereof is still widely debated. Here we show that astrophysically relevant super-critical quasi-perpendicular magnetized collisionless shocks can be produced and characterized in the laboratory. We observe the characteristics of super-criticali…
Discovery of the proton emitting nucleus $^{159}$Re
2007
Fund. para Cienc. Tecnol., FCT, Minist. Cienc. Tecnol.;Fundacao Calouste Gulbenkian;Fundacao Luso-Americana
Bimodal Acidity at the Amorphous Silica/Water Interface
2015
International audience; Understanding the microscopic origin of the acid base behavior of mineral surfaces in contact with water is still a challenging task, for both the experimental and the theoretical communities. Even for a relatively simple material, such as silica, the origin of the bimodal acidity behavior is still a debated topic. In this contribution we calculate the acidity of single sites on the humid silica surface represented by a model for the hydroxylated amorphous surface. Using a thermodynamic integration approach based on ab initio molecular dynamics, we identify two different acidity values. In particular, some convex geminals and some type of vicinals are very acidic (pK…
Reactivity of antitumor coinage metal-based N-heterocyclic carbene complexes with cysteine and selenocysteine protein sites
2021
Abstract The reaction of the antitumor M(I)-bis-N-heterocyclic carbene (M(I)-NHC) complexes, M = Cu, Ag, and Au, with their potential protein binding sites, i.e. cysteine and selenocysteine, was investigated by means of density functional theory approaches. Capped cysteine and selenocysteine were employed to better model the corresponding residues environment within peptide structures. By assuming the neutral or deprotonated form of the side chains of these amino acids and by considering the possible assistance of an external proton donor such as an adjacent acidic residue or the acidic component of the surrounding buffer environment, we devised five possible routes leading to the binding o…