Search results for "CA [SR]"

Properties and generation by irradiation of germanium point defects in Ge-doped silica

2012

Ge doped amorphous silicon dioxide (Ge doped silica) has attracted the attention of researchers for more than 50 years. This material is used in many different technological fields from electronics, to telecommunication, to optics. In particular, it is widely used for the production of optical fibers and linear and nonlinear optical devices. The optical fibers, which allow to transmit optical signals with high speed avoiding interferences, are constituted by two regions with different refractive index values: core (inner part) and cladding (external part). To increase the refractive index of the core with respect to that of cladding, Ge doping of silica is commonly used. Moreover, in the Ge…

PVA-GTA Fricke gel dosimeters exposed to clinical photons beams: Nuclear Magnetic Resonance Relaxometry and Imaging

2016

Fricke Gel (FXGs) dosimetric system is based on the radiation induced oxidation of ferrous to ferric ions. The application of Fricke gels for ionizing radiation dosimetry is continuously increasing worldwide due to their many favorable properties. However, one of their shortcomings is that ferrous and ferric ions diffuse in the gel matrix. To maintain the spatial integrity of the dose distribution, Fricke gels must be undergoing measurement within a few hours of their irradiation, so that ferric ions remain close to their point of production. Thus, the spatial integrity of the dose distribution in the Fricke gel is maintained (Schreiner, 2015). The gel matrix also contributes to the oxidati…

Glycogen phosphorylase from flight muscle of the hawk moth, Manduca sexta: purification and properties of three interconvertible forms and the effect…

1994

Glycogen phosphorylase (EC 2.4.1.1) of Manduca sexta flight muscle was separated into three distinct peaks of activity on diethylaminoethyl-Sephacel. The three fractions of phosphorylase activity were further purified by affinity chromatography on AMP-Sepharose and shown to have the same relative molecular mass (=178000) on polyacrylamide gradient gel electrophoresis under non-denaturating conditions and to produce subunits of molecular mass =92000 on SDS gelelectrophoresis. On the basis of their kinetic properties with respect to the activator AMP and the inhibitor caffeine, the three fractions of phosphorylase activity were assigned as follows: peak 1=phosphorylase b (unphosphorylated for…

Gel di Fricke: studio della risposta NMR in funzione della concentrazione di ferro ed utilizzo dosimetrico in ambito clinico (3D MRI)

2014

Photo-Activated Phosphorescence of Ultrafine ZnS:Mn Quantum Dots: On the Lattice Strain Contribution

2021

We address the enhancement of orange-light luminescence of Mn-doped zinc sulfide nanoparticles (NPs) induced by exposure to UV light. Ultrafine ZnS:Mn NPs are prepared by microwave-assisted crystal growth in ethanol, without adding any dispersant agents. When exposed to UV light, their orange emission intensity undergoes a strong increase. This effect is observed when the NPs are deposited as a thin layer on a transparent substrate or dispersed in an ethanolic suspension. Such a feature was already observed on polymer- or surfactant-coated ZnS:Mn NPs and explained as a passivation effect. In this study, by coupling X-ray photoelectron, Fourier transform infrared, and electron paramagnetic r…

Two-Color Radiation Generated in a Seeded Free-Electron Laser with Two Electron Beams.

2015

We present the experimental evidence of the generation of coherent and statistically stable two-color free-electron laser radiation obtained by seeding an electron beam double peaked in energy with a laser pulse single spiked in frequency. The radiation presents two neat spectral lines, with time delay, frequency separation, and relative intensity that can be accurately controlled. The analysis of the emitted radiation shows a temporal coherence and a shot-to-shot regularity in frequency significantly enhanced with respect to the self-amplified spontaneous emission. © 2015 American Physical Society. © 2015 American Physical Society.

A general framework for collecting and analysing the tracking data of cruise passengers at the destination

2016

Cruise passengers’ behaviour at the destination is a rather poorly investigated phenomenon. The single exit/entry point and the relatively brief visiting time, which characterize cruise passengers’ experience at their destinations, make the use of GPS technology particularly suitable for the analysis of such a relevant phenomenon. The aim of this research is to propose a general framework for collecting and analysing GPS tracking data relating to cruise passengers’ behaviour at their destination. The main prerequisites and research stages for the implementation of surveys on cruise passengers will be described and a set of tools and measures for the analysis of GPS tracking data will be pro…

Does genetic population structure of Ambrosina bassii L. (Araceae, Ambrosineae) attest a post-Messinian land-bridge between Sicily and Africa?

2012

Abstract Aim of the present work is the analysis (through the study of enzyme polymorphism) of Sicilian and African (Tunisian) populations of Ambrosina bassii , a small perennial endemic to the Central-Western Mediterranean basin, in order to verify if the complex geological history of this part of the Mediterranean area left its mark in the present-day genetic structure of this taxon. Starch gel allozyme electrophoresis of seven putative loci of A. bassii was employed to estimate genetic diversity, genetic structure and gene flow. Populations from Sicily, Tunisia and Sardinia (as outgroup) were sampled. Results show that Sicily populations have 4 private alleles, Sardinia 3, Tunisia just o…

Genetic diversity and local population structure in Ambrosina bassii (Araceae, Ambrosineae), a Mediterranean relict species

2009

The effects of habitat fragmentation on the genetic structure of Ambrosina bassii are analyzed. The species, whose reproductive biology is mostly unknown, is the only representative of its genus and tribe and it is endemic to the central Mediterranean area. The selected study area was the island of Sicily, in which wild populations show a wide morphological variability and ecological amplitude. Patterns of within- and among-population genetic diversity in eleven Sicilian populations, occurring in six disjunct areas, were examined by means of allozyme electrophoresis. High levels of genetic diversity were found as shown by the mean expected heterozygosity (He ¼ 0.263), the percentage of poly…

Genetic diversity in Sicilian populations of Quercus ilex (Fagaceae)

2013

Raimondo, F. M., Scialabba, A., Guarino, R. & Spallino, R. E.: Genetic diversity in Sicilian populations of Quercus ilex (Fagaceae). — Fl. Medit. 23: 245-253. 2013. — ISSN: 1120-4052 printed, 2240-4538 online. Recent studies on the genetic structure of the Italian populations of Quercus ilex demonstrated their high diversity, particularly in the Sicilian metapopulation. In order to check if the holm oak stands in the mountains of NW Sicily could have some relationship with Q. ilex subsp. ballota (distributed in Spain and NW Africa), 26 specimens from the Sicilian most distinctive Q. ilex populations have been compared with some representative populations of the Italian Peninsula, North Afri…