236 research outputs found

    A Methodology to Account for the Finger Non-Uniformity in Photovoltaic Solar Cell

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    Abstract In this work we investigate the impact of a non-uniform finger in the front-side metallization on the performance of c-Si solar cells. For this purpose, we propose a methodology based on a mixed-mode simulation approach, which allows evaluating the solar cell properties by performing both numerical device simulations and circuit simulations. The finger roughness profile is modeled by means of Gaussian function. The impact of roughness on the solar cell efficiency is studied as a function of mean finger height, mean finger width and finger resistivity. The proposed methodology has been applied to typical roughness profiles realized with two different metallization techniques, the conventional single screen-printing (SP) and the double screen-printing (DP)

    Hospital discharges-based search of acute flaccid paralysis cases 2007-2016 in Italy and comparison with the National Surveillance System for monitoring the risk of polio reintroduction

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    Background: Acute flaccid paralysis (AFP) surveillance has been adopted globally as a key strategy for monitoring the progress of the polio eradication initiative. Hereby, to evaluate the completeness of the ascertainment of AFP cases in Italy, a hospital-discharges based search was carried out. Methods: AFP cases occurring between 2007 and 2016 among children under 15 years of age were searched in the Italian Hospital Discharge Records (HDR) database using specific ICD-9-CM diagnostic codes. AFP cases identified between 2015 and 2016 were then compared with those notified to the National Surveillance System (NSS). Results: Over a 10-year period, 4163 hospital discharges with diagnosis of AFP were reported in Italy. Among these, 956 (23.0%) were acute infective polyneuritis, 1803 (43.3%) myopathy, and 1408 (33.8%) encephalitis, myelitis and encephalomyelitis. During the study period, a decreasing trend was observed for all diagnoses and overall the annual incidence rate (IR) declined from 5.5 to 4.5 per 100,000 children. Comparing NSS with HDR data in 2015-2016, we found a remarkable underreporting, being AFP cases from NSS only 14% of those recorded in HDR. In particular, the acute infective polyneuritis cases reported to NSS accounted for 42.6% of those detected in HDR, while only 0.9% of myopathy cases and 13.1% of encephalitis/myelitis/encephalomyelitis cases have been notified to NSS. The highest AFP IRs per 100,000 children calculated on HDR data were identified in Liguria (17.4), Sicily (5.7), and Veneto (5.1) Regions; regarding the AFP notified to the NSS, 11 out of 21 Regions failed to reach the number of expected cases (based on 1/100,000 rate), and the highest discrepancies were observed in the Northern Regions. Overall, the national AFP rate was equal to 0.6, therefore did not reach the target value. Conclusions: AFP surveillance data are the final measure of a country's progress towards polio eradication. The historical data obtained by the HDR have been useful to assess the completeness of the notification data and to identify the Regions with a low AFP ascertainment rate in order to improve the national surveillance system

    HER2-based recombinant immunogen to target DCs through FcγRs for cancer immunotherapy

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    Dendritic cell (DC)-based immunotherapy is an attractive approach to induce long lasting antitumor effector cells aiming to control cancer progression. DC targeting is a critical step in the design of DC vaccines in order to optimize delivery and processing of the antigen, and several receptors have been characterized for this purpose. In this study, we employed the FcγRs to target DCs both in vitro and in vivo. We designed a recombinant molecule (HER2-Fc) composed of the immunogenic sequence of the human tumor-associated antigen HER2 (aa 364–391) and the Fc domain of a human IgG1. In a mouse model, HER2-Fc cDNA vaccination activated significant T cell-mediated immune responses towards HER2 peptide epitopes as detected by IFN-γ ELIspot and induced longer tumor latency as compared to Ctrl-Fc-vaccinated control mice. Human in vitro studies indicated that the recombinant HER2-Fc immunogen efficiently targeted human DCs through the FcγRs resulting in protein cross-processing and in the activation of autologous HER2-specific CD8+ T cells from breast cancer patients

    Face Mask Use in the Community for Reducing the Spread of COVID-19: A Systematic Review.

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    Background: Evidence is needed on the effectiveness of wearing face masks in the community to prevent SARS-CoV-2 transmission. Methods: Systematic review and meta-analysis to investigate the efficacy and effectiveness of face mask use in a community setting and to predict the effectiveness of wearing a mask. We searched MEDLINE, EMBASE, SCISEARCH, The Cochrane Library, and pre-prints from inception to 22 April 2020 without restriction by language. We rated the certainty of evidence according to Cochrane and GRADE approach. Findings: Our search identified 35 studies, including three randomized controlled trials (RCTs) (4,017 patients), 10 comparative studies (18,984 patients), 13 predictive models, nine laboratory experimental studies. For reducing infection rates, the estimates of cluster-RCTs were in favor of wearing face masks vs. no mask, but not at statistically significant levels (adjusted OR 0.90, 95% CI 0.78–1.05). Similar findings were reported in observational studies. Mathematical models indicated an important decrease in mortality when the population mask coverage is near-universal, regardless of mask efficacy. In the best-case scenario, when the mask efficacy is at 95%, the R0 can fall to 0.99 from an initial value of 16.90. Levels of mask filtration efficiency were heterogeneous, depending on the materials used (surgical mask: 45–97%). One laboratory study suggested a viral load reduction of 0.25 (95% CI 0.09–0.67) in favor of mask vs. no mask. Interpretation: The findings of this systematic review and meta-analysis support the use of face masks in a community setting. Robust randomized trials on face mask effectiveness are needed to inform evidence-based policies. PROSPERO registration: CRD42020184963

    Discovery of chemotherapy-associated ovarian cancer antigens by interrogating memory T cells

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    According to the immunogenic cell death hypothesis, clinical chemotherapy treatments may result in CD8(+) and CD4(+) T-cell responses against tumor cells. To discover chemotherapy-associated antigens (CAAs), T cells derived from ovarian cancer (OC) patients (who had been treated with appropriate chemotherapy protocols) were interrogated with proteins isolated from primary OC cells. We screened for immunogenicity using two-dimensional electrophoresis gel-eluted OC proteins. Only the selected immunogenic antigens were molecularly characterized by mass-spectrometry-based analysis. Memory T cells that recognized antigens associated with apoptotic (but not live) OC cells were correlated with prolonged survival in response to chemotherapy, supporting the model of chemotherapy-induced apoptosis as an adjuvant of anti-tumor immunity. The strength of both memory CD4(+) and CD8(+) T cells producing either IFN- or IL-17 in response to apoptotic OC antigens was also significantly greater in Responders to chemotherapy than in nonresponders. Immunogenicity of some of these antigens was confirmed using recombinant proteins in an independent set of patients. The T-cell interrogation system represents a strategy of reverse tumor immunology that proposes to identify CAAs, which may then be validated as possible prognostic tumor biomarkers or cancer vaccines

    Face Mask Use in the Community for Reducing the Spread of COVID-19: A Systematic Review

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    Background: Evidence is needed on the effectiveness of wearing face masks in the community to prevent SARS-CoV-2 transmission. / Methods: Systematic review and meta-analysis to investigate the efficacy and effectiveness of face mask use in a community setting and to predict the effectiveness of wearing a mask. We searched MEDLINE, EMBASE, SCISEARCH, The Cochrane Library, and pre-prints from inception to 22 April 2020 without restriction by language. We rated the certainty of evidence according to Cochrane and GRADE approach. / Findings: Our search identified 35 studies, including three randomized controlled trials (RCTs) (4,017 patients), 10 comparative studies (18,984 patients), 13 predictive models, nine laboratory experimental studies. For reducing infection rates, the estimates of cluster-RCTs were in favor of wearing face masks vs. no mask, but not at statistically significant levels (adjusted OR 0.90, 95% CI 0.78–1.05). Similar findings were reported in observational studies. Mathematical models indicated an important decrease in mortality when the population mask coverage is near-universal, regardless of mask efficacy. In the best-case scenario, when the mask efficacy is at 95%, the R0 can fall to 0.99 from an initial value of 16.90. Levels of mask filtration efficiency were heterogeneous, depending on the materials used (surgical mask: 45–97%). One laboratory study suggested a viral load reduction of 0.25 (95% CI 0.09–0.67) in favor of mask vs. no mask. / Interpretation: The findings of this systematic review and meta-analysis support the use of face masks in a community setting. Robust randomized trials on face mask effectiveness are needed to inform evidence-based policies. / PROSPERO registration: CRD42020184963

    Evaluation of flu vaccination coverage among healthcare workers during a 3 years’ study period and attitude towards influenza and potential covid-19 vaccination in the context of the pandemic

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    (1) Background: vaccination of healthcare workers (HCWs) against seasonal influenza is considered the most effective way to protect HCWs, ensure patient’s safety and to maintain essential health care services during influenza epidemics. With the present study we aimed to evaluate the efficacy of incremental bundles of measures implemented during the last three flu campaigns and to assess the attitudes towards influenza vaccination and a potential vaccine against COVID-19 among HCWs, in a large university hospital in Pisa, Italy. (2) Methods: We described measures implemented during 2018/2019, 2019/2020 and 2020/2021 and assessed their impact on flu vaccine coverage (VC) among employees and residents in Pisa university hospital. We considered sex, profession and ward to investigate differences in uptake. In addition, in 2020 a survey was developed and distributed to all employees to evaluate flu and COVID-19 vaccines attitudes. (3) Results: during the 2018/19 and 2019/20 flu campaigns the overall VC rate among HCWs was, respectively, 10.2% and 11.9%. In 2020/21 the overall VC rate jumped to 39.3% (+230.6%). Results from the survey indicated a more positive attitude towards flu vaccine as compared to COVID-19 vaccines among the 10.6% of the staff members who responded to the survey. In addition, 70.97% of HCWs totally agreed that being vaccinated against influenza would be more important than the previous years because of COVID-19 emergency. (4) Conclusions: a significant increase in VC was observed in 2020/21, especially among those sub-groups with consistently lower uptake in previous years. The COVID-19 pandemic positively influenced flu vaccination uptake during the 2020/21 season

    On the magnetosphere-ionosphere coupling during the May 2021 geomagnetic storm

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    On 12 May 2021 the interplanetary doppelganger of the 9 May 2021 coronal mass ejection impacted the Earth's magnetosphere, giving rise to a strong geomagnetic storm. This paper discusses the evolution of the various events linking the solar activity to the Earth's ionosphere with special focus on the effects observed in the circumterrestrial environment. We investigate the propagation of the interplanetary coronal mass ejection and its interaction with the magnetosphere-ionosphere system in terms of both magnetospheric current systems and particle redistribution, by jointly analyzing data from interplanetary, magnetospheric, and low Earth orbiting satellites. The principal magnetospheric current system activated during the different phases of the geomagnetic storm was correctly identified through the direct comparison between geosynchronous orbit observations and model predictions. From the particle point of view, we have found that the primary impact of the storm development is a net and rapid loss of relativistic electrons from the entire outer radiation belt. Our analysis shows no evidence for any short-term recovery to pre-storm levels during the days following the main phase. Storm effects also included a small Forbush decrease driven by the interplay between the interplanetary shock and subsequent magnetic cloud arrival
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