310 research outputs found

    Capacitance study of thin film SnO2:F/p-type a-Si:H heterojunctions

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    Abstract We characterized SnO 2 :F/p-type a-Si:H heterojunctions by current-voltage (I-V) and capacitance-voltage (C-V) measurements at room temperature to determine the junction parameters. Samples with circular geometry and different diameters were characterized. The current scales with the junction area, and the current density J as a function of the voltage V is a slightly asymmetric curve with a super-linear behaviour (cubic law) for high voltages. Using a transmission line model valid for devices with circular geometry, we studied the effects of the SnO 2 :F resistivity on the measured capacitance when the SnO2:F layer works as an electrical contact. The measured C-V curve allows us to determine junction parameters as doping of p-type a-Si:H, built-in potential and depletion width for the heterojunction with the smallest diameters, demonstrating that for these samples the TCO effects can be neglected. We compared theoretical and measured data to explain qualitatively the transport mechanism in this heterojunction

    A non-contact optical technique for vehicle tracking along bounded trajectories

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    This paper presents a method for measuring the non-controlled trajectory of a cart along a bounded rectilinear path. The method uses non-contact measurement devices to identify the position of a movable laser scanner working in helical mode in order to reconstruct the 3D model of bridges. The main idea of the proposed method is to use vision systems in order to identify the coordinates of the laser scanner placed on the cart with respect to the global reference system. A fit-to-purpose vision system has been implemented: the system uses three CCD's cameras mounted on the cart to identify the relative rotations with respect to the environment. Two lasers pointers and a laser distance meter are fixed at the starting point of the trajectory and pointing in the direction of motion of the cart, creating three dots on a plane placed on the cart. One of the camera detects the cart displacements and rotations in the plane using a blob analysis procedure. The method described in this paper has a constant uncertainty and the measurement range only depends on the lasers power. The theoretical accuracy of the measurement system is close to 1 mm for the translation along the motion direction and around 0.5 mm along the other two directions. Orientations measurement have a theoretical accuracy of less than 0.1 °. The solution has been implemented for the 3D reconstruction of concrete bridge; preliminary experimental results are presented and discussed

    PARTICIPATORY APPROACH FOR THE ENHANCEMENT OF ARCHITECTURALARCHIVES FUNDS: THE EXPERIENCE AT MUSEO DELLA RAPPRESENTAZIONE IN CATANIA

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    Abstract. This paper describes the results of a participatory approach experienced during the training of university and high school students at the MuRa (Museo della Rappresentazione). Mura is a university museum belonging to the Department of Civil Engineering and Architecture at University of Catania. It houses and exhibits the collections of architectural projects of Francesco Fichera and a series of chalcographies including the collection of the renown engraver Giovan Battista Piranesi. The training program has been addressed at the documentation, visualization and communication of the architectures realized by Francesco Fichera and other Sicilian architects in the city centre of Catania in the first half of XXth century, whose projects are hosted by the museum. The methodology adopted has included the experimentation of participatory strategies aimed at the communication and the narration of the architectures built in the early twentieth century in Catania. After a preliminary training phase on digital tools for 3D documentation and enhancement of architectural heritage, the students were invited to participate with their ideas and creative expressions in the dissemination actions of the identified case studies

    High Grade Glioma Treatment in Elderly People: Is It Different Than in Younger Patients? Analysis of Surgical Management Guided by an Intraoperative Multimodal Approach and Its Impact on Clinical Outcome

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    Objective: Age is considered a negative prognostic factor for High Grade Gliomas (HGGs) and many neurosurgeons remain skeptical about the benefits of aggressive treatment. New surgical and technological improvements may allow extended safe resection, with lower level of post-operative complications. This opportunity opens the unsolved question about the most appropriate HGG treatment in elderly patients. The aim of this study is to analyze if HGG maximal safe resection guided by an intraoperative multimodal imaging protocol coupled with neuromonitoring is associated with differences in outcome in elderly patients versus younger ones. Methods: We reviewed 100 patients, 53 (53%) males and 47 (47%) females, with median (IQR) age of 64 (57; 72) years. Eight patients were diagnosed with Anaplastic Astrocytoma (AA), 92 with Glioblastoma (GBM). Surgery was aimed to achieve safe maximal resection. An intraoperative multimodal imaging protocol, including neuronavigation, neurophysiological monitoring, 5-ALA fluorescence, 11C MET-PET, navigated i-US system and i-CT, was used, and its impact on EOTR and clinical outcome in elderly patients was analyzed. We divided patients in two groups according to their age: 65 years, and surgical and clinical results (EOTR, post-operative KPS, OS and PFS) were compared. Yet, to better understand age-related differences, the same patient cohort was also divided into 70 years and all the above data reanalyzed. Results: In the first cohort division, we did not found KPS difference over time and survival analysis did not show significant difference between the two groups (p = 0.36 for OS and p = 0.49 for PFS). Same results were obtained increasing the age cut-off for age up to 70 years (p = 0.52 for OS and p = 0.92 for PFS). Conclusions: Our data demonstrate that there is not statistically significant difference in post-operative EOTR, KPS, OS, and PFS between younger and elderly patients treated with extensive tumor resection aided by a intraoperative multimodal protocol

    Muon calibration of the ASTRI-Horn telescope: preliminary results

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    Astri-Horn is a Small-Sized Telescope (SST) for very-high energy gamma-ray astronomy installed in Italy at the INAF "M.C. Fracastoro" observing station (Mt. Etna, Sicily). The ASTRI-Horn telescope is characterized by a dual-mirror optical system and a curved focal surface covered by SiPM sensors managed by a innovative fast front-end electronics. Dedicated studies were performed to verify the feasibility of the calibration through muons on the relatively small size of the primary mirror (~4 m diameter), as in the case of larger Cherenkov telescopes. A number of tests were performed using simulations of the atmospheric showers with the CORSIKA package and of the telescope response with a dedicated simulator. In this contribution we present a preliminary analysis of muon events detected by ASTRI-Horn during the regular scientific data taking performed in December 2018 and March 2019. These muon events validate the results obtained with the simulations and definitively confirm the feasibility of calibrating the ASTRI-Horn SST telescope with muons.Comment: Proceedings of the 36th International Cosmic Ray Conference, Madison, Wisconsin, USA, 24 July-1 August 201

    Post-mortem findings in vaccine-induced thrombotic thombocytopenia

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    Greinacher et al.1 and Schultz et al.2 were the first to independently report the main clinical and laboratory features of 11 and five respective patients from Germany, Austria and Norway who developed life-threatening thrombohemorrhagic complications 5 to 16 days after the administration of the first dose of the chimpanzee adenoviral vector vaccine ChAdOx1nCoV-19 against SARS-CoV-2 and COVID-19. Subsequently Scully et al.3 reported similar findings in 23 patients treated with the same vaccine in the United Kingdom. More recently, See et al.4 reported a case series of 12 patients from the USA with cerebral venous sinus thrombosis following the vaccination with Ad26.CoV2.S employing a human adenoviral vector. The main post-vaccination features common to the case series were the occurrence of venous thromboembolism mainly in unusual sites (cerebral and abdominal veins) and the concomitant presence of bleeding symptoms associated with severe thrombocytopenia, often accompanied by laboratory signs of consumption coagulopathy with low plasma fibrinogen and hugely increased levels of D-dimer. The majority of reported patients reacted positively for serum immunoglobulin G (IgG) antibodies to the platelet factor 4 PF4/heparin complex. 1-4 Another common feature was the high mortality rate. The mechanism of this very rare thrombohemorrhagic syndrome was postulated to be a vaccine-triggered autoimmune reaction, with the development of antibodies against a still ill-defined PF4/polyanion complex that causes platelet activation as in heparin-induced thrombocytopenia (HIT),1-4 notwithstanding the fact that no cases were exposed to heparin before the onset of thrombosis and thrombocytopenia. We report herewith the detailed post-mortem macroscopic and microscopic findings in two similar cases that occurred in the Italian region of Sicily

    Maintaining good practice in breast cancer management and reducing the carbon footprint of care: study protocol and preliminary results

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    Objective: Health care accounts for up to 8-10% of greenhouse emission yearly in the US and surgical room contributes an estimated 25-30% of hospital waste. Despite the major role of greenhouse emissions because of surgery, little has been done by surgeons to reduce their impact. In this paper, we present a multicentric retrospective analysis to evaluate the carbon footprint of the most common breast surgical treatment and a preliminary analysis of our results. Patients and Methods: Retrospective analysis with processed-based life cycle assessment (LCA) has been obtained to determine carbon footprint of different surgical procedures. In our preliminary study, we enrolled all consecutive patients undergoing breast conserving procedure (BCP) between 9th March 2019 and 9th March 2021 to underline the reduction in fuel consumption with postoperative telehealth application (pre-COVID-19 vs. COVID-19). A propensity score matching was implemented to optimize comparability. Results: From 276 BCP patients, PSM included 69 pre-COVID-19 and 69 COVID-19 groups, respectively. No statistically significant difference was found in the tumor stage, marital status, and distance from the hospital. A total of 466 postoperative visits was performed and a statistically significant difference in telehealth visit rate was found between groups (1.75% vs. 51.68%; p<0.001). A reduction of 4312.38 km in travel to the hospital was found in the COVID-19 group. No difference was found in postoperative complications. Conclusions: Health systems worldwide are implementing zero-carbon programs to reduce their carbon footprint. Breast surgeons should consider the consequences of their actions and embrace the pillars of the circular economy. Our data could promote further action in order to raise awareness regarding carbon footprint of breast surgery

    A study of methyl formate in astrochemical environments

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    Several complex organic molecules are routinely detected in high abundances towards hot cores and hot corinos. For many of them, their paths of formation in space are uncertain, as gas phase reactions alone seem to be insufficient. In this paper, we investigate a possible solid-phase route of formation for methyl formate (HCOOCH3). We use a chemical model updated with recent results from an experiment where simulated grain surfaces were irradiated with 200 keV protons at 16 K, to simulate the effects of cosmic ray irradiation on grain surfaces. We find that this model may be sufficient to reproduce the observed methyl formate in dark clouds, but not that found in hot cores and corinos.Comment: 6 pages, 2 figures, 2 tables Accepted by MNRA
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