Search results for "induced"

Regional hypothermia of the kidney: surface or transarterial perfusion cooling? A functional study.

1980

Hypothermia reduces ischemic damage if prolonged occlusion of the renal artery is required during an in situ kidney operation. Hypothermia may be achieved by external cooling or by transarterial hypothermic perfusion. External cooling may lower intrarenal temperature heterogeneously. Perfusion techniques via intra-arterial catheters introduced percutaneously are associated with minimal technical difficulties. The 95 patients who underwent extensive hypothermic nephrolithotomy had differential 131iodine hippuran clearance studies preoperatively, and 2 weeks and 6 to 46 months postoperatively. Sixty-three kidneys were cooled by transarterial hypothermic perfusion and 39 were cooled with topic…

Polymerization reactions and modifications of polymers by ionizing radiation

2020

International audience; Ionizing radiation has become the most effective way to modify natural and synthetic polymers through crosslinking, degradation, and graft polymerization. This review will include an in-depth analysis of radiation chemistry mechanisms and the kinetics of the radiation-induced C-centered free radical, anion, and cation polymerization, and grafting. It also presents sections on radiation modifications of synthetic and natural polymers. For decades, low linear energy transfer (LLET) ionizing radiation, such as gamma rays, X-rays, and up to 10 MeV electron beams, has been the primary tool to produce many products through polymerization reactions. Photons and electrons in…

Prussian Blue Analogues of Reduced Dimensionality

2012

Abstract: Mixed-valence polycyanides (Prussian Blue analogues) possess a rich palette of properties spanning from room-temperature ferromagnetism to zero thermal expansion, which can be tuned by chemical modifications or the application of external stimuli (temperature, pressure, light irradiation). While molecule-based materials can combine physical and chemical properties associated with molecular-scale building blocks, their successful integration into real devices depends primarily on higher-order properties such as crystal size, shape, morphology, and organization. Herein a study of a new reduced-dimensionality system based on Prussian Blue analogues (PBAs) is presented. The system is …

Induced smoothing in LASSO regression

The thesis is being carried out with the National research Council at the Institute of Biomedicine and Molecular Immunology "Alberto Monroy" of Palermo, where I am a fellow, under the supervision of MD Stefania La Grutta. Our research unit is focused on clinical research in allergic respiratory problems in children. In particular, we are interested in to assess the determinants of impaired lung function in a sample of outpatient asthmatic children aged between 5 and 17 years enrolled from 2011 to 2017. Our dataset is composed by n = 529 children and several covariates regarding host and environmental factors. This thesis focuses on hypothesis testing in lasso regression, when one is interes…

Fabrication and electro-optical characterization of Ruthenium-based Dye-Sensitized Solar Cells

2015

In this paper, we measure the main photoelectrical parameters of Dye Sensitized Solar Cells (DSSCs) based on ruthenium complexes at different irradiance levels, incident wavelengths, temperatures and hours of light soaking

Experimental characterization of Ruthenium-based Dye Sensitized Solar Cells and study of light-soaking effect impact on performance

2016

In this paper, we present an experimental investigation on the performance of Ruthenium-based Dye Sensitized Solar Cells (DSSCs) at different irradiance levels, incident wavelengths and hours of illumination. In particular, the measurements have been aimed at studying the performance variation due to light soaking effect since this phenomenon has noteworthy practical implications, such as stability tests of DSSCs. Our results show that the short circuit current density, the open circuit voltage and the conversion efficiency η increase with the hours of light soaking. Finally, the observed phenomenon is reversible, and thus the performance decreases again when the cell is kept in the dark.

Characterization of thin film CIG(S,SE)2 submodules using solar simulator and laser beam induced current techniques (Versione estesa)

2015

In this work, the electrical and optical characterization of CIG(S, Se)2 sub-modules using both a solar simulator equipment and the Laser Beam Induced Current (LBIC) technique is presented. By using the solar simulator and a proper set-up, the electrical parameters of the modules at varying irradiance and temperatures are determined. In addition, the LBIC measurements are carried out to analyze the 2D photocurrent uniformity of the modules at two different wavelengths. Dispersion values of extracted parameters can be very useful for practically tuning the modelling stage at device/module level.

Characterization of Thin Film CIG(S,Se)2 submodules using Laser Beam Induced Current Technique

2015

Nowadays, an important class of thin film solar cells consists of CuInGa(S,Se)2 (CIGSSe) solar cells, i.e., composed of Copper, Indium, Gallium, Sulfur and Selenide. Thanks to their electrical and optical properties and to the technological development, thin film integrated photovoltaic modules have nowadays obtained relatively good values of efficiency. In this work, we have performed the electrical and optical characterization of a CIGSSe sub-module by using both a solar simulator equipment and the Laser Beam Induced Current (LBIC) technique.

Characterization of laser ablation of copper in the irradiance regime of laser-induced breakdown spectroscopy analysis

2014

Abstract The LIBS signal depends both on the ablated mass and on the plasma excitation temperature. These fundamental parameters depend in a complex manner on laser ablation and on laser–plasma coupling. As several works in the literature suggest that laser ablation processes play a predominant role compared to plasma heating phenomena in the LIBS signal variations, this paper focuses on the study of laser ablation. The objective was to determine an interaction regime enabling to maximally control the laser ablation. Nanosecond laser ablation of copper at 266 nm was characterized by scanning electron microscopy and optical profilometry analysis, in air at 1 bar and in the vacuum. The laser …

Time resolved confocal luminescence investigations on reverse proton exchange Nd : LiNbO3 channel waveguides

2009

In this work we report on the time and spatial resolved fluorescence of Neodymium ions in LiNbO(3) channel waveguides fabricated by Reverse Proton Exchange. The analysis of the fluorescence decay curves obtained with a sub-micrometric resolution has evidenced the presence of a relevant fluorescence quenching inside the channel waveguide. From the comparison between diffusion simulations and the spatial dependence of the (4)F(3/2) fluorescence decay rate we have concluded that the observed fluorescence quenching can be unequivocally related to the presence of H+ ions in the LiNbO(3) lattice. Nevertheless, it turns out that Reverse Proton Exchange guarantees a fluorescence quenching level sig…