1,104 research outputs found

    Cars Diagnostic on a PhotochemicalReactor for IR Laser Induced Production of Si and Si3N4 Powders

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    In a flow reactor a low power (up to 50 W) CW CO2 laser tuned at 944,19 cm−1 has been focussed in order to produce Si and Si3N4 ultrafine powders from SiH4 and SiH4/NH3 mixtures.Among possible on-line optical diagnostics, two different CARS techniques have been used to monitor the excitation process and to measure average reaction temperatures in collinear geometry. In broad-band CARS at low resolution (≈6.0 cm−1) the reactant temperature is measured from the attenuation of the corresponding integrated peak intensity below and at the dissociation threshold. In narrow-band experiments the temperature reached by the dissociating reactants below and above the threshold is inferred from the spectral shape (measured with 0.2 cm−1 resolution) of the envelope of rovibrational CARS transitions involved.Results obtained at the threshold for SiH4 dissociation are in agreement with previous data on gas-phase pyrolysis in a thermal process. For the SiH4/NH3 reaction the difficulty in obtaining stoichiometric Si3N4 has been related to the cooling effect of large NH3 addition to the SiH4 warmed up in the laser absorption

    Spectral database of Renaissance fresco pigments by LIBS, LIF and colorimetry

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    A set of about 70 fresco samples made with pigments and binders typical of the Renaissance period in Rome has been characterized by LIBS, LIF and colorimetric measurements in order to build an as much as possible complete database. Aiming at providing the restorers and art historians with a useful tool for the study of ancient frescoes, the samples have been prepared in agreement with the Cennino Cennini recipes for both materials and procedures. Afterward, the obtained spectral data have been processed by means of multivariate analysis methods in order to find the most significant features that can help in fast characterization and recognition of real unknown specimens

    Endothelin-1: a new autocrine/paracrine factor in rat testis.

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    Cultured Sertoli cells of 20-day-old rats were found to produce and release endothelin-1-like immunoreactivity (ET-1-LI) under follicle-stimulating hormone control. The elution profile of ET-1-LI from extracts of spent Sertoli cell culture medium corresponds to that of synthetic ET-1, suggesting a testicular production of authentic ET-1. In contrast, the conditioned medium from rat Leydig cells did not contain ET-1-LI. Immunohistochemical studies confirmed that, in 20-day-old rats, the positive staining was confined to some Sertoli cells, whereas interstitial cells were negative. In the adult rat testis the positivity was not limited to the tubular compartment (Sertoli cells) but was also present in the interstitium. A high concentration (13 pmol/mg protein) of high-affinity (dissociation constant = 0.6 nM) 125I-labeled ET-1 binding sites was present in Leydig cells. These sites bind ET-1 and ET-2 with 1,000-fold higher affinity than ET-3, suggesting that they correspond to the subtype ETA of the ET receptors. Specific 125I-ET-1 binding sites are present also in Sertoli cells but are 50-fold less concentrated than in Leydig cells. Our results suggest an autocrine/paracrine role for ET-1 in rat testis. </jats:p

    Laser remote sensing calibration of ocean color satellite data

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    world ocean: in fact, those processes dramatically affect the climatic equilibrium of our planet. For this reason, many advanced active and passive remote sensors have been used to study phytoplankton dynamics, since such phenomena are thought to be responsible for the sequestration of atmospheric carbon dioxide, one of the most important greenhouse gases. In this paper, one laser system and three satellite radiometers routinely used for the study of the phytoplankton dynamics will be briefly reviewed. Satellite sensors have been preferred to airborne sensors because, to our knowledge, ocean color airborne radiometers have not been operated in Antarctica, at least not throughout the whole lapse of time examined in this study. Particular focus was on the laser system (ELF) and on a specific satellite radiometer (SeaWiFS). ELF is based on the laser-induced fluorescence of phytoplankton pigments and was conceived for the Italian expeditions to Antarctica. The goal of SeaWiFS is to provide the Earth science community with quantitative data on the global ocean bio-optical properties. Such satellite radiometer has been calibrated with in situ data mainly acquired in non polar regions. This is why a comparison between ELF and SeaWiFS measurements of chlorophyll-a surface concentrations in the Southern Ocean during the austral summer 1997-1998 was believed to be significant. Our results indicate that SeaWiFS overestimates high concentrations and underestimates low concentrations. In order to correct this behavior, the chlorophyll- a bio-optical algorithm of SeaWiFS has been recalibrated according to the measurements of ELF, thus providing a new estimation of the primary production in the Southern Ocean

    3D models acquisition and image processing for virtual musealization of the spezieria di Santa Maria della Scala, Rome

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    This study was carried out within the project 'Roma Hispana. Nuevas tecnologías aplicadas al estudio histórico, la musealización y la puesta en valor de Patrimonio Cultural español en Roma: la spezieria di Santa Maria della Scala' (Universitat de ValÚncia Spain), which is funded by the Conselleria d'Innovació, Universitats, CiÚncia i Societat Digital of the Generalitat Valenciana (2020-2021) and authorized by the Sovrintendenza Speciale Archeologia Belle Arti e Paesaggio (Special Superintendence of Archeology, Fine Arts and Landscape) of Rome, Italy. The spezieria di Santa Maria della Scala was the oldest apothecary in Europe managed by the order of Discalced Carmelite friars. Operating between the second half of the seventeenth century and the mid-twentieth century, over time it acquired great prestige, becoming known as the Pharmacy of the Popes. The aims of the 'Roma Hispana' project are to study, musealize and disseminate the material and immaterial cultural heritage of this historical spezieria by combining physicochemical and cultural studies, new 3D technologies, and artificial intelligence. As a case study, in this paper we report the application of a laser scanner prototype for 3D color imaging of the spezieria's sales room and use a simpler photogrammetry method to collect analogous data in the small nearby storeroom coupled to the high-power capabilities of the ENEA parallel computer facility. Digital data were collected to enable a virtual tour that provides a fully navigable, faithful, high-resolution 3D color model to render this ancient Roman apothecary accessible and usable to interested members of the public and experts in the sector (art historians, restorers, etc.). We also describe the 3D technology used to obtain threedimensional images of the cultural assets of these spaces (mostly drug containers) and its results. The ultimate aim of this study is to achieve the virtual musealization of the heritage complex

    Multi-Approach Study Applied to Restoration Monitoring of a 16th Century Wooden Paste Sculpture

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    Inglés : A multi-approach study has been designed to evaluate the mannerist-style masterpiece of the Christ of the Expiration (Museum Brotherhood, Seville, Spain), a polychrome wooden paste sculpture of the 16th Century that was restored in the Andalusian Historical Heritage Institute (IAPH). During is intervention, a combination of two non-destructive prototypes were used to evaluate the different color in its feet regarding its legs and torso and its cause. A portable equipment that combined X-ray diffraction (XRD) an X-Ray fluorescence (XRF) was employed to analyze chemical composition and mineralogical characterization of pigments. This equipment allowed obtaining simultaneously XRF and XRD at the same point without sampling. X-ray techniques identified cerussite, hydrocerussite and barite in different layers. The presence of zinc oxide from a recent restoration was also detected. Additionally, laser induced fluorescent (LIF) was employed to assess the presence of different fluorescent compounds on the surface. This technique showed the use of acrylic products in the feet, loincloth and torso of Christ from previus restoration and allowed to detect spectral difference on the feet and a high ration of the acrylic product on feet, both could be the cause of the differential degradation between the feet and torso. This multi-approach study based on portable and non-destructive techniques allowed restoration monitoring and helped restorens to take decisions without sampling

    Report on LIF measurements in Seville. Part 2: Santa Ana church

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    A scientific cooperation between ENEA UTAPRAD (Frascati) and the Natural Sciences Department of the “Pablo de Olavide” University in Seville, has started aimed at developing and testing innovative diagnostic instrumentation for Cultural Heritage preservation. Here we report the results obtained in a joint campaign carried on in Seville during February 2010 in the Santa Ana church in Seville (SP). Several wood paintings have been thoroughly investigated by means of Laser Induced Fluorescence scan system along the lines of the Research Pro ject “Non Destructive Techniques” managed by IAPH (Consejería de Cultura de la Junta de Andalucía).The field activities, developed as part of a conservation project carried out by IPAH, were devoted to the determination of retouches, traces of former restorations and detection of chemicals (wax, consolidants, etc.) on the surface under analysis not otherwise documented

    Report on LIF measurements in Seville. Part 1: Virgen del Buen Aire chapel

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    Within the frame of a scientific cooperation between ENEA UTAPRAD (Frascati) and UPO Natural Sciences Dep. (Seville), aimed at developing and testing innovative diagnostic instrumentation for Cultural Heritage preservation, this report deals with results obtained in a joint campaign carried on in Seville during February 2010. Namely the data acquired by the ENEA LIF scanning system operated on fresco’s in Virgen del Buen Aire Chapel are presented here. The Virgen del Buen Aire Chapel has been studied according to the Research Project of “Non Destructive Techniques” managed by IAPH (Consejería de Cultura de la Junta de Andalucía). The results have been also implemented as part of a conservation project carried out by IAPH. LIF images are discussed in term of evaluating former restoration actions, in particular retouches on pigments and consolidant additions on a painted wall and two vaults. Statistical approaches and projection operators have been utilized for elaborating the images in order to handle the large number of spectra collected in each scanned point by our hyper-spectral system

    Effect of Lockdowns on Hospital Staff in a COVID Center: A Retrospective Observational Study

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    At the onset of the SARS-CoV-2 pandemic, individual and social measures were strengthened through restrictive non-pharmaceutical interventions, labelled with the term "lockdown". In Italy, there were two lockdowns (9 March 2020-3 May 2020 and 3 November 2020-27 March 2021). As part of preventive measures, healthcare workers and the administrative staff population of Policlinico A. Gemelli underwent nasopharyngeal swab tests from 1 March 2020 to 9 February 2022, a long time interval that includes the two aforementioned lockdowns. The population included 8958 people from 1 March 2020 to 31 December 2020; 8981 people from 1 January 2021 to 31 December 2021; and 8981 people from 1 January 2022 to 9 February 2022. We then analysed pseudo-anonymized data, using a retrospective observational approach to evaluate the impact of the lockdown on the incidence of SARS-CoV-2 infections within the population. Given the 14 day contagious period, the swab positivity rate (SPR) among the staff decreased significantly at the end of the first lockdown, every day prior to 18 May 2020, by 0.093 (p &lt; 0.0001, CI = (-0.138--0.047)). After the fourteenth day post the end of the first lockdown (18 May 2020), the SPR increased daily at a rate of 0.024 (p &lt; 0.0001, 95% CI = (0.013-0.034)). In addition, the SPR appeared to increase significantly every day prior to 17 November 2020 by 0.024 (p &lt; 0.0001, CI = (0.013-0.034)). After the fourteenth day post the start of the second lockdown (17 November 2020), the SPR decreased daily at a rate of 0.039 (p &lt; 0.0001, 95% CI = (-0.050--0.027)). These data demonstrate that, in our Institution, the lockdowns helped to both protect healthcare workers and maintain adequate standards of care for COVID and non-COVID patients for the duration of the state of emergency in Italy

    Correction to: Two years later: Is the SARS-CoV-2 pandemic still having an impact on emergency surgery? An international cross-sectional survey among WSES members

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    Background: The SARS-CoV-2 pandemic is still ongoing and a major challenge for health care services worldwide. In the first WSES COVID-19 emergency surgery survey, a strong negative impact on emergency surgery (ES) had been described already early in the pandemic situation. However, the knowledge is limited about current effects of the pandemic on patient flow through emergency rooms, daily routine and decision making in ES as well as their changes over time during the last two pandemic years. This second WSES COVID-19 emergency surgery survey investigates the impact of the SARS-CoV-2 pandemic on ES during the course of the pandemic. Methods: A web survey had been distributed to medical specialists in ES during a four-week period from January 2022, investigating the impact of the pandemic on patients and septic diseases both requiring ES, structural problems due to the pandemic and time-to-intervention in ES routine. Results: 367 collaborators from 59 countries responded to the survey. The majority indicated that the pandemic still significantly impacts on treatment and outcome of surgical emergency patients (83.1% and 78.5%, respectively). As reasons, the collaborators reported decreased case load in ES (44.7%), but patients presenting with more prolonged and severe diseases, especially concerning perforated appendicitis (62.1%) and diverticulitis (57.5%). Otherwise, approximately 50% of the participants still observe a delay in time-to-intervention in ES compared with the situation before the pandemic. Relevant causes leading to enlarged time-to-intervention in ES during the pandemic are persistent problems with in-hospital logistics, lacks in medical staff as well as operating room and intensive care capacities during the pandemic. This leads not only to the need for triage or transferring of ES patients to other hospitals, reported by 64.0% and 48.8% of the collaborators, respectively, but also to paradigm shifts in treatment modalities to non-operative approaches reported by 67.3% of the participants, especially in uncomplicated appendicitis, cholecystitis and multiple-recurrent diverticulitis. Conclusions: The SARS-CoV-2 pandemic still significantly impacts on care and outcome of patients in ES. Well-known problems with in-hospital logistics are not sufficiently resolved by now; however, medical staff shortages and reduced capacities have been dramatically aggravated over last two pandemic years
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