174 research outputs found

    IMMIGRAZIONE, SICUREZZA, QUARTIERE. UNO STUDIO TRA MILANO E MADRID

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    This thesis aims at investigating the application of local security measures in two different multicultural neighbourhoods: via Padova in Milan and Lavapi\ue9s in Madrid. Comparing this two areas helps to understand how the concept and the practice of "security" is connected with the criminalization of immigrants both in Italy and in Spain. Moreover, the approval of measures with a local target permits to underline the connection existing between security, immigration and the neighbourhood as privileged space of social control. Relying on different approaches towards the concepts of "immigration", "security" and "neighbourhood", and 64 semi-structured interviews, this work proposes a specifical focus on the perception of security of the residents of the analyzed neighbourhoods. The residents interviewed are italians, spanish and immigrants from different countries that gathered in the neighbourhood, building networks, associations and social struggle.\ua

    Versatile lithium fluoride thin-film solid-state detectors for nanoscale radiation imaging

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    Point defects in insulating materials are successfully used for radiation detectors. Among them, colour centres in lithium fluoride (LiF) are well known for application in dosimeters and in light-emitting devices and lasers. LiF thin-film detectors for extreme ultraviolet radiation, soft and hard X-rays, based on photoluminescence from aggregate electronic defects, are currently under development for imaging application with laboratory radiation sources, e.g. laser-driven plasma sources and conventional X-ray tubes, as well as large-scale facilities, e.g. synchrotrons and free-electron lasers. Among the peculiarities of these detectors, noteworthy ones are the very high intrinsic spatial resolution ( 1 cm2) and the wide dynamic range. Moreover, they are insensitive to ambient light and no development process is needed. The latent images stored in the LiF thin layer can be read with fluorescence optical microscopy techniques. These detectors prove to be highly versatile, as LiF is sensitive to almost any kind of radiation, including charged particles and neutrons, and can be grown in the form of polycrystalline thin films, whose photoluminescence response can be tailored trough the control of the growth conditions

    Optical spectroscopy and microscopy of radiationinduced light-emitting point defects in lithium fluoride crystals and films

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    Broad-band light-emitting radiation-induced F₂ and F₃⁺ electronic point defects, stable and laser-active at room temperature in lithium fluoride crystals and films, find applications in dosimeters, tuneable color-center lasers, broad-band miniaturized light sources and in novel radiation imaging detectors. A brief review of their photoemission properties is presented, and their peculiarities at liquid nitrogen temperature are discussed. A few experimental results about optical spectroscopy and fluorescence microscopy of these radiation-induced point defects in LiF crystals and thin films are presented to obtain information about the coloration curves, the point defects formation efficiency, the effects of the photo-bleaching processes, and so on. The control of local formation, stabilization and transformation of radiation-induced light-emitting defect centers is crucial for the development of optical active micro-components and nanostructures. Some of the advantages of low temperature measurements for novel confocal laser scanning fluorescence microscopy techniques, widely used for the spatial mapping of these point defects thorough the optical reading of their visible photoluminescence, are highlighted

    Silicon nanoparticles as active materials for LED: laser synthesis and functionalization for tuning luminescence

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    Silicon nanocrystals (SiNPs) are an extensively studied light-emitting material due to their inherent biocompatibility and easy integration with silicon-based technology. Although low luminescence quantum yields of as-prepared SiNPs, the exploitation of the surface chemistry of SiNPs plays a key role in tuning their luminescence. In this work, the development of SiNPs as active materials for innovative LEDs was investigated. SiNPs were synthesized by using laser pyrolysis, a very flexible tool for lab-scale production in developmental quantities. The synthesized SiNPs have dimensions from 5 to 15 nm and high purity grade but show weak luminescence. For this reason, chemical treatments were performed on SiNPs: surface modifications lead to an improvement of their luminescence properties. Chemical and optical characterization were performed by conventional and advanced techniques, such as FTIR, BET, UV-VIS absorption and emission, XPS, TEM and confocal Raman. A Life Cycle Assessment (LCA) study of laser synthesis of SiNPs was conducted with the aim to identify the potential environmental impacts coming from this production method

    High resolution and high efficiency coloration of lithium fluoride by soft X-rays irradiation

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    The efficient coloration of LiF material, in the form of bulk and films, by EUV and soft X-rays emitted by a laser-plasma source is demonstrated. The short penetration depth of soft-X-rays is exploited to obtain high spatial resolution luminescent patterns while the high dynamic range of proportionality between X-ray dose and coloration is exploited for using LiF as image detector in micro-radiography and soft X-ray microscopy applications

    Erythropoietin (EPO) haplotype associated with all-cause mortality in a cohort of Italian patients with Type-2 Diabetes

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    Type-2 Diabetes (T2D), diabetic complications, and their clinical risk factors harbor a substantial genetic component but the genetic factors contributing to overall diabetes mortality remain unknown. Here, we examined the association between genetic variants at 21 T2D-susceptibility loci and all-cause mortality in an elderly cohort of 542 Italian diabetic patients who were followed for an average of 12.08 years. Univariate Cox regression analyses detected age, waist-to-hip ratio (WHR), glycosylated haemoglobin (HbA1c), diabetes duration, retinopathy, nephropathy, chronic kidney disease (CKD), and anaemia as predictors of all-cause mortality. When Cox proportional hazards multivariate models adjusted for these factors were run, three erythropoietin (EPO) genetic variants in linkage disequilibrium (LD) with each other (rs1617640-T/G, rs507392-T/C and rs551238-A/C) were significantly (False Discovery Rate < 0.1) associated with mortality. Haplotype multivariate analysis revealed that patients carrying the G-C-C haplotype have an increased probability of survival, while an opposite effect was observed among subjects carrying the T-T-A haplotype. Our findings provide evidence that the EPO gene is an independent predictor of mortality in patients with T2D. Thus, understanding the mechanisms by which the genetic variability of EPO affects the mortality of T2D patients may provide potential targets for therapeutic interventions to improve the survival of these patients

    Evidences of +896 A/G TLR4 Polymorphism as an Indicative of Prevalence of Complications in T2DM Patients

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    T2DMis today considered as world-wide health problem, with complications responsible of an enhanced mortality and morbidity. Thus, new strategies for its prevention and therapy are necessary. For this reason, the research interest has focused its attention on TLR4 and its polymorphisms, particularly the rs4986790. However, no conclusive findings have been reported until now about the role of this polymorphism in development of T2DM and its complications, even if a recent meta-analysis showed its T2DM association in Caucasians. In this study, we sought to evaluate the weight of rs4986790 polymorphism in the risk of the major T2DMcomplications, including 367 T2DMpatients complicated for the 55.6%. Patients with A/A and A/G TLR4 genotypes showed significant differences in complication\u2019s prevalence. In particular, AG carriers had higher risk prevalence for neuropathy (P = 0.026), lower limb arteriopathy (P = 0.013), and the major cardiovascular pathologies (P = 0.017). Their cumulative risk was significant (P = 0.01), with a threefold risk to develop neuropathy, lower limb arteriopathy, and major cardiovascular events in AG cases compared to AA cases.The adjusted OR for the confounding variables was 3.788 (95% CI: 1.642\u20138.741).Thus, the rs4986790 polymorphism may be an indicative of prevalence of complications in T2DM patients

    Contact X-ray microscopy of living cells by using LiF crystal as imaging detector

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    In this paper, the use of lithium fluoride (LiF) as imaging radiation detector to analyse living cells by single-shot soft X-ray contact microscopy is presented. High resolved X-ray images on LiF of cyanobacterium Leptolyngbya VRUC135, two unicellular microalgae of the genus Chlamydomonas and mouse macrophage cells (line RAW 264.7) have been obtained utilizingX-ray radiation in the water window energy range from a laser plasma source. The used method is based on loading of the samples, the cell suspension, in a special holder where they are in close contactwith a LiF crystal solid-state Xray imaging detector. After exposure and sample removal, the images stored in LiF by the softX-ray contactmicroscopy technique are read by an optical microscope in fluorescence mode. The clear image of the mucilaginous sheath the structure of the filamentous Leptolyngbya and the visible nucleolus in the macrophage cells image, are noteworthiness results. The peculiarities of the used X-ray radiation and of the LiF imaging detector allow obtaining images in absorption contrast revealing the internal structures of the investigated samples at high spatial resolution. Moreover, thewidedynamicrangeof theLiF imaging detector contributes to obtain high-quality images. In particular, we demonstrate that this peculiar characteristic of LiF detector allows enhancing the contrast and reveal details even when they were obscured by a nonuniform stray light

    Lithium fluoride coloration by laser-plasma soft x-rays: A promising tool for X-ray microscopy and photonics

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    A new imaging detector for EUV or soft-X-ray radiation based on optically stimulated luminescence (OSL) of lithium fluoride (LiF) films or crystals is presented. The first micro-radiography images of biological samples and of meshes obtained on LiF using a laser-plasma source or an X-ray laser are shown, and (up to now) a resolution better than one micron is demonstrated. The dependence of the coloration density vs the deposited X-ray dose is considered and the advantages of this new diagnostic technique for both coherent and non-coherent EUV sources, compared with CCDs detectors, photographic films and photoresists are discussed. This new detector is extremely suitable for laser plasmas and for X-ray lasers sources
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