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Light trapping and luminescence have been observed in polydimethylsiloxane (PDMS) foils containing about 0.1-0.2 wt% gold nanoparticles (AuNPs). The so-prepared PDMSs have been physically characterized using SEM microscopy, UV-Vis, FTIR and Raman spectroscopies. The used AuNPs have been controlled by means of the surface plasmon resonance absorption spectra. In the AuNPs-PDMS foils, a luminescence peak at about 425 nm has been induced by an exciting light at 280 nm. The light injection with an optical fiber is trapped inside the polymer-containing NPs and illuminates all the polymer volume. The measurements of scattered light show an increment in the light intensity due to the presence of AuNPs and air bubbles inducing diffractions, reflections and Mie scattering. Further investigations have been conducted irradiating the PDMS with AuNPs in vacuum with 2.9 MeV proton beams producing luminescence in the blue region. The mechanisms of light trapping and luminescence and the possible applications of the prepared material are presented and discussed.

Embolization in pediatric patients encompasses a large spectrum of indications, ranging from the elective treatment of congenital diseases of the cardiovascular system to the urgent management of acute hemorrhagic conditions. In particular, the endovascular treatment of central and peripheral vascular malformations and hypervascular tumors represents a wide chapter for both congenital and acquired situations. Thanks to the progressive availability of low-profile endovascular devices and new embolic materials, the mini-invasive approach has gradually overtaken surgery. In this review, the main embolization procedures will be illustrated and discussed, with a focus on clinical indications and expected outcomes. The most recent mini-invasive techniques will be described, with hints on the cutting-edge devices and embolic materials.

This work introduces an innovative new method to transport gold nanoparticles (Au-NPs) toward specific organs using as transporter the M13 filamentous phage. The aim is to improve the radiotherapy efficiency by injecting gold nanoparticles in the tumor tissues in order to increase the effective atomic number and, consequently, to produce higher locally deposited doses. The biocompatible Au-NPs can be bonded to the phage surface for their transport in the biological fluids and tissues. M13 phages can be prepared to arrive in specific tissues and organs depending on their biochemical preparation and functionalization. Evidence about the real attachment of spherical Au-NPs, 10 nm in diameter, to the M13 phages is obtained using different microscopies. Other analyses have been also performed to evaluate the number of gold nanoparticles that can be transported by M13 phages inside the organism. Our results on the study of the spherical Au-NP size distribution, deduced by AFM, EFM, and TEM analyses, have indicated that in average, 2 couples of Au-NPs are attached to each phage. Moreover, the size of the NPs ranges between 10 and 30 nm, demonstrating a little aggregation of the nanoparticles, which remain usefully sized to be vehicled with the blood flux towards specific organs.

The ever-stronger attention paid to enhancing safety in the workplace has led to novel sensor development and improvement. Despite the technological progress, nanostructured sensors are not being commercially transferred due to expensive and non-microelectronic compatible materials and processing approaches. In this paper, the realization of a cost-effective sensor based on ultrathin silicon nanowires (Si NWs) for the detection of nitrogen dioxide (NO2) is reported. A modification of the metal-assisted chemical etching method allows light-emitting silicon nanowires to be obtained through a fast, low-cost, and industrially compatible approach. NO2 is a well-known dangerous gas that, even with a small concentration of 3 ppm, represents a serious hazard for human health. We exploit the particular optical and electrical properties of these Si NWs to reveal low NO2 concentrations through their photoluminescence (PL) and resistance variations reaching 2 ppm of NO2. Indeed, these Si NWs offer a fast response and reversibility with both electrical and optical transductions. Despite the macro contacts affecting the electrical transduction, the sensing performances are of high interest for further developments. These promising performances coupled with the scalable Si NW synthesis could unfold opportunities for smaller sized and better performing sensors reaching the market for environmental monitoring.

A simple, cost-effective approach to realize a sensitive temperature sensor based on IR laser reduced graphene oxide (IRLrGO) is reported. The sensor has been obtained by irradiating a graphene oxide (GO) film, placed between two thin glass substrates, with a continuous wave diode laser operating at 970 nm along its entire length. A conductive strip, 13 mm long, 300 μm wide and 7 μm thick, has been generated by moving the GO film on an X-Y translator stage with a given velocity with respect to the fixed laser fiber tip position. The laser treatment has given rise to the GO reduction confirmed by the resistance R measurements as well as from SEM, EDX, ATR-FTIR and Raman analyses. The temperature dependence of the conductive strip resistance has been measured in air from 30ˆC to 80ˆC and in high vacuum from 80 K to 300 K. The sample acts as a sensitive and low mass Resistance Temperature Detector (RTD). Such a sensor is biocompatible and requires a very low bias (

Nanostructures are arising as novel biosensing platforms promising to surpass current performance in terms of sensitivity, selectivity, and affordability of standard approaches. However, for several nanosensors, the material and synthesis used make the industrial transfer of such technologies complex. Silicon nanowires (NWs) are compatible with Si-based flat architecture fabrication and arise as a hopeful solution to couple their interesting physical properties and surface-to-volume ratio to an easy commercial transfer. Among all the transduction methods, fluorescent probes and sensors emerge as some of the most used approaches thanks to their easy data interpretation, measure affordability, and real-time in situ analysis. In fluorescent sensors, Si NWs are employed as substrate and coupled with several fluorophores, NWs can be used as quenchers in stem-loop configuration, and have recently been used for direct fluorescent sensing. In this review, an overview on fluorescent sensors based on Si NWs is presented, analyzing the literature of the field and highlighting the advantages and drawbacks for each strategy.

Measurements of electrical conductivity were carried out at temperatures ranging between 77 K and 450 K on high vacuum thermal reduced graphene oxide (rGO) films. The investigated samples were characterized in composition and structure before being analyzed in terms of electrical conduction. Their electrical conductivity was also measured in air at room temperature. Measurements have demonstrated that at first graphene oxide (GO) was not stable both in air and vacuum. It stabilized after having been subjected to 7 thermal cycles under high vacuum conditions, about 10−7 torr, up to a Tmax of 450 K. At room temperature the initial GO material had a very low conductivity, of the order of 10−10 Ω−1 x cm−1, which increased to about 2.5 Ω−1x cm−1 when it was thermal stabilized in rGO. The stabilization process, induced by the high vacuum heating procedure, seems due to a good reduction of GO, which gives rise to such expansion of the conjugated π-electron system that a band-like transport with small thermal activation energies (Ea = 10–50 meV) occurs. The performed electrical conductivity measurements are presented and discussed.

A full-size prototype of a Micromegas precision tracking chamber for the upgrade of the ATLAS detector at the LHC Collider has been built between October 2015 and April 2016. This paper describes in detail the procedures used in constructing the single modules of the chamber in various INFN laboratories and the final assembly at the Laboratori Nazionali di Frascati (LNF). Results of the chamber exposure to the CERN SPS/H8 beam line in June 2016 are also presented. The performances achieved in the construction and the results of the test beam are compared with the requirements, which are imposed by the severe environment during the data-taking of the LHC foreseen for the next years., Contact editors: G. Mancini, A. Kourkoumeli-Charalampidi

Graphene oxide (GO) is an electrical insulator as most of the carbon atoms in this material are sp3-hybridized. Its physical, optical and chemical properties depend on the type and degree of reduction process. Presently, copper ion irradiation of GO foil has been performed at Ion Beam Center of the Helmholtz-Zentrum Dresden-Rossendorf to investigate the behavior of a set of GO foils under this irradiation at low energy and different fluences up to 5 × 1016 ions/cm2. The compositional and optical properties of graphene oxide have been studied as a function of the fluences of implanted copper ions in the wavelength range 400–1000 nm. The results of ellipsometry microscopy, helium Rutherford backscattering spectroscopy, elastic recoil detection analysis, Raman spectroscopy and SEM-EDX measurements will be presented and discussed.

In recent years graphene and its derivatives, have attracted scientific interest due to their unique properties. This study is to explore the quality of synthesized graphene oxide and reduced graphene oxide foils under the irradiation of protons and helium ions of the same energy and current. Fully characterizations by Raman spectroscopy, Rutherford backscattering spectrometry and Elastic recoil detection analysis and the relative results are presented. The effects of parameters, such as type of ions, their current and irradiation time, are studied. The quality of large-scale fabrication of graphene oxide and reduced graphene oxide (rGO) is important for industrial and research applications of these materials. An overview on the changes in the optical property and electron conductivity of graphene oxide and reduced graphene oxide under irradiation by protons, helium and carbon ions are also summarized.

Graphene oxide (GO) is prepared as a self-supporting thin film by a liquid solution of GO. The so-obtained GO films have been characterized in terms of thickness and density. The GO film composition and trace elements have been measured with Rutherford backscattering spectrometry (RBS) and Elastic recoil detection analysis (ERDA), using MeV helium ion beams. The presence of crystalline and amorphous phases has been also investigated with X-ray diffraction (XRD) and the morphology by scanning electron microscopy (SEM). Information about the GO film structure, oxidation degree and thickness has been deduced by means of Fourier transform infrared spectroscopy (FT-IR), Raman and optical spectroscopy (ultraviolet-visible-near infrared spectroscopy, UV-Vis-nIR). In particular, the GO film thickness varies from sub-micrometric values up to micrometric ones. Furthermore, the GO film heating in air up to 60 °C produces oxidation effects as deduced from the interpretation of our data.

Random optical media (ROM) are a novel class of photonic materials characterized by a disordered assembly of the elementary constituents (such as particles, wires and fibers), that determines unique scattering, absorption and emission properties. The propagation of light in ROM is affected by the size and optical properties (refractive index, absorption and emission wavelengths) of their components, as well as by the overall 3-dimensional architecture. So far, most of the investigated ROM have been realized using liquid dispersions or bulk samples embedding colloidal nanoparticles or porous systems. While nanowire-based ROM are poorly investigated, such materials can feature new optical effects related to the elongated shape of their building blocks and to their light-transport properties. Here we report on the fabrication and on the morphological and spectroscopic characterization of hybrid organic-inorganic nanowires, realized by doping polymers with dielectric nanoparticles. We investigate light diffusion and multi-scattering properties of 3- dimensional ROM formed by organic and hybrid nanowires, as well as field localization in 2-dimensional networks. The influence of nanowire geometry and composition on the scattering properties is also discussed.

We describe the experimental set-up of the Radioactive Ion Beam (RIB) in-flight facility EXOTIC consisting of: (a) two position-sensitive Parallel Plate Avalanche Counters (PPACs), dedicated to the event-by-event tracking of the produced RIBs and to time of flight measurements and (b) the new high-granularity compact telescope array EXPADES (EXotic PArticle DEtection System), designed for nuclear physics and nuclear astrophysics experiments employing low-energy light RIBs. EXPADES consists of eight Δ E – E res telescopes arranged in a cylindrical configuration around the target. Each telescope is made up of two Double Sided Silicon Strip Detectors (DSSSDs) with a thickness of 40/60 μm and 300 μm for the Δ E and Eres layer, respectively. Additionally, eight ionization chambers were constructed to be used as an alternative Δ E stage or, in conjunction with the entire DSSSD array, to build up more complex triple telescopes. New low-noise multi-channel charge-sensitive preamplifiers and spectroscopy amplifiers, associated with constant fraction discriminators, peak-and-hold and Time to Amplitude Converter circuits were developed for the electronic readout of the Δ E stage. Application Specific Integrated Circuit-based electronics was employed for the treatment of the Eres signals. An 8-channel, 12-bit multi-sampling 50 MHz Analog to Digital Converter, a Trigger Supervisor Board for handling the trigger signals of the whole experimental set-up and an ad hoc data acquisition system were also developed. The performance of the PPACs, EXPADES and of the associated electronics was obtained offline with standard α calibration sources and in-beam by measuring the scattering process for the systems 17O+58Ni and 17O+208Pb at incident energies around their respective Coulomb barriers and, successively, during the first experimental runs with the RIBs of the EXOTIC facility.

The structural organization in selected room temperature ionic liquids, namely (a) butyl-, (b) hexyl- and (c) octyl-3-methylimidazolium hexafluorophosphate, is investigated by means of X-ray diffraction. We find novel experimental evidences of the existence of a high degree of intermediate range order that is associated to nanoscale segregation of the alkyl chains into the charged matrix. The size of these structural heterogeneities depends linearly from the alkyl chain length. A similar behaviour had been observed in other systems, such as normal alcohols. The slope of such dependence provides hints on the nature of the structural organization of these segregated domains.

The induced changes of the flatband voltage by the location of holes in a silicon-rich oxide (SRO) film sandwiched between two thin SiO 2 layers [used as gate dielectric in a metal-oxide-semiconductor (MOS) capacitor] can be used as the two states of a memory cell. The principle of operation is based on holes permanently trapped in the SRO layer and reversibly moved up and down, close to the metal and the semiconductor, in order to obtain the two logic states of the memory. The concept has been verified by suitable experiments on MOS structures. The device exhibits an excellent endurance behavior and, due to the low mobility of the holes at low field in the SRO layer, a much longer refresh time compared to conventional dynamic random access memory cells. © 2002 American Institute of Physics.

Structural properties of silicon rich oxide films (SRO) have been investigated by means of micro-Raman spectroscopy and transmission electron microscopy (TEM). The layers were deposited by plasma enhanced chemical vapor deposition using different SiH4/O2 gas mixtures. The Raman spectra of the as-deposited SRO films are dominated by a broad band in the region 400-500 cm-1 typical of a highly disordered silicon network. After annealing at temperatures above 1000°C in N2, the formation of silicon nanocrystals is observed both in the Raman spectra and in the TEM images. However, most of the precipitated silicon does not crystallize and assumes an amorphous microstructure. © 2002 The Electrochemical Society. All rights reserved.