87 research outputs found

    Study for the scientific development of the Sardinia Radio Telescope/SDSA configured for solar observations and radio-science aimed at Space Weather and Fundamental Physics applications

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    The Sun produces radiation across virtually the entire electromagnetic spectrum, each frequency range helps to better understand a different aspect of our star. In the radio domain, it is an interesting celestial object to study for the richness of physical phenomena that involve not only the astrophysical area of interest, but also plasma, nuclear and fundamental physics. However, even after decades of studies, our star still presents lots of mysteries. My PhD aims to investigate the Sun environment and its emission mechanism in the radio domain to better understand some of the complex solar phenomena, their connections and find applications in the Space Weather and Fundamental Physics fields. This work is possible thanks to new challenging development of the radio telescopes managed by the Italian National Institute of Astrophysics (INAF) and the Italian Space Agency (ASI) in a joint collaboration. SRT is an ideal instrument for this Thesis project thanks to its double configuration: Sardinia Deep Space Antenna (SDSA)/radio astronomy for radio science experiments and solar imaging. The SDSA is in the implementation phase. We are inquiring the most stringent observation scientific requirements that would be necessary to prepare the antenna to perform interplanetary spacecraft tracking in radio-science configuration. The radio-astronomy configuration is already operative and has permitted us to monitor the Sun for the last few years in K-band (18-26 GHz). Moreover, the Medicina radio telescope is fully equipped to perform solar observation and has contributed considerably to the solar imaging studies. Starting 2018, we obtained more than 300 maps of the entire solar disk in the K-band, filling the observational gap in the field of solar imaging at these frequencies. I performed a new calibration procedure adopting the Supernova Remnant Cas A as a flux reference, which provided typical errors <3% for the estimation of the quiet-Sun level components. My work includes a study on the active regions brightness and spectral characterization. The interpretation of the observed emission as thermal bremsstrahlung components combined with gyro-magnetic variable emission paves the way for the use of our system for long-term monitoring of the Sun. We are also starting to explore possible interesting connections between macro-features in our data and explosive Space Weather Phenomena

    Myrtus polyphenols, from antioxidants to anti-inflammatory molecules: Exploring a network involving cytochromes P450 and Vitamin D

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    Inflammatory response represents one of the main mechanisms of healing and tissue function restoration. On the other hand, chronic inflammation leads to excessive secretion of pro-inflammatory cytokines involved in the onset of several diseases. Oxidative stress condition may contribute in worsening inflammatory state fall, increasing reactive oxygen species (ROS) production and cytokines release. Polyphenols can counteract inflammation and oxidative stress, modulating the release of toxic molecules and interacting with physiological defenses, such as cytochromes p450 enzymes. In this paper, we aimed at evaluating the anti-inflammatory properties of different concentrations of Myrtus communis L. pulp and seeds extracts, derived from liquor industrial production, on human fibroblasts. We determined ROS production after oxidative stress induction by H 2 O 2 treatment, and the gene expression of different proinflammatory cytokines. We also analyzed the expression of CYP3A4 and CYP27B1 genes, in order to evaluate the capability of Myrtus polyphenols to influence the metabolic regulation of other molecules, including drugs, ROS, and vitamin D. Our results showed that Myrtus extracts exert a synergic effect with vitamin D in reducing inflammation and ROS production, protecting cells from oxidative stress damages. Moreover, the extracts modulate CYPs expression, preventing chronic inflammation and suggesting their use in development of new therapeutic formulations

    Pathogenic and Prognostic Roles of Paraneoplastic Leukocytosis in Cervical Cancer: Can Genomic-Based Targeted Therapies Have a Role? A Literature Review and an Emblematic Case Report

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    Tumor-associated leukocytosis has been associated with poor prognosis in cervical cancer. Leukemoid reaction (i.e., white blood cell count &gt; 40,000/µL) is defined paraneoplastic (PLR) when it occurs in the presence of a cytokine-secreting tumor (CST) without neoplastic bone marrow infiltration. Cervical cancers displaying PLR represent a peculiar entity characterized by a rapidly progressive behavior typically associated with chemo-radioresistance. The present paper aims to review the literature about the pathogenetic mechanisms of PLR and its prognostic role in cervical cancer. Moreover, it reports the emblematic case of a patient with an advanced cervical cancer associated with PLR that was chemotherapy resistant. The patient underwent a palliative cytoreductive surgery of high complexity, obtaining a temporary regression of PLR. The tumor sample stained positive for G-CSF and IL-6, thus indicating a CST. Notably, the tumor genomic analysis revealed a PI3CKA mutation. Therefore, at the instrumental evidence of a rapidly progressive disease relapse, which was accompanied by reappearance of PLR, we started a targeted treatment with a selective PIK3 inhibitor alpesilib combined with the JAK1-2 inhibitor ruxolitinib. We achieved a relief of symptoms and leukocytosis; however, severe side effects necessitated the treatment suspension. In conclusion, as therapeutic strategies for cancer with PLR are scarcely reported in literature, our study could contribute to expand our understanding of the topic and provide a basis for further research

    A Python approach for solar data analysis: SUNDARA (SUNDish Active Region Analyser), preliminary development

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    This technical note describes the Python package SUNDARA (SUNDish Active Region Analyser), a sophisticated code - fully self-consistent - aimed at the data analysis of solar images. This analysis is crucial for the INAF Proposal "SunDish Project" (PI: A. Pellizzoni), active since 2018 and devoted to imaging and monitoring the solar atmosphere at high radio frequencies (at present 18 - 26 GHz) through single-dish observations with INAF radio telescopes (SRT and Medicina). SUNDARA, characterised by a very user-friendly widget, allows to automatically unearth Active Regions (ARs) across the solar disk (or on its edge) through several algorithms; these ARs are modelled through an elliptical 2D-Gaussian kernel. In little more than 5 minutes, SUNDARA produces a complete analysis of a solar map, saving a directory containing images, plots and several tables with physical information of the solar disk and ARs (brightness temperatures, fluxes and spectral indices, with respective errors). A deeper analysis (that can be completed in a few hours) is possible thanks to a Bayesian approach based on Markov Chain MonteCarlo (MCMC) simulations. Moreover, these identified ARs are automatically associate in position with the detected ARs at other observing frequencies, reported in the Heliophysics Event Knowledgebase (HEK) used by the astrophysics and solar physics communities. SUNDARA has been successfully tested on a large amount of data from solar maps implemented with the radio telescopes of the INAF Network. For the purposes of this technical note, we report only two cases (one for Medicina, and one for SRT). This Python package constitutes a crucial tool for the INAF Network to analyse solar images (the Space Weather monitoring network and forecast along the solar cycle will be soon available), and to provide a complete overview of the astrophysical phenomena

    Co-Transplantation of endothelial progenitor cells and pancreatic islets to induce long-lasting normoglycemia in streptozotocin-treated diabetic rats

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    Graft vascularization is a crucial step to obtain stable normoglycemia in pancreatic islet transplantation. Endothelial progenitor cells (EPCs) contribute to neoangiogenesis and to the revascularization process during ischaemic events and play a key role in the response to pancreatic islet injury. In this work we co-transplanted EPCs and islets in the portal vein of chemically-induced diabetic rats to restore islet vascularization and to improve graft survival. Syngenic islets were transplanted, either alone or with EPCs derived from green fluorescent protein (GFP) transgenic rats, into the portal vein of streptozotocin-induced diabetic rats. Blood glucose levels were monitored and intraperitoneal glucose tolerance tests were performed. Real time-PCR was carried out to evaluate the gene expression of angiogenic factors. Diabetic-induced rats showed long-lasting (6 months) normoglycemia upon co-transplantation of syngenic islets and EPCs. After 3–5 days from transplantation, hyperglycaemic levels dropped to normal values and lasted unmodified as long as they were checked. Further, glucose tolerance tests revealed the animals' ability to produce insulin on-demand as indexed by a prompt response in blood glucose clearance. Graft neovascularization was evaluated by immunohistochemistry: for the first time the measure of endothelial thickness revealed a donor-EPC-related neovascularization supporting viable islets up to six months after transplant. Our results highlight the importance of a newly formed viable vascular network together with pancreatic islets to provide de novo adequate supply in order to obtain enduring normoglycemia and prevent diabetes-related long-term health hazards

    The genetic diversity of Sardinian myrtle ( Myrtus communis L.) populations

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    Background: The myrtle ( Myrtus communis ) is a common shrub widespread in the Mediterranean Basin. Its fruit and leaves exhibit antioxidant, antibacterial and antifungal properties, and are used for their content of essential oils and for their medicinal properties, but most commonly as an ingredient in locally made liquor. The uncontrolled exploitation of natural stands has reduced both the species\' geographical coverage and the size of individual populations. The selection of genotypes for controlled cultivation requires a characterization of the genetic diversity present both within and between populations. Results: Genotypic variation was evaluated using ISSR profiling and genetic diversity characterized using standard population genetics approaches. Two major clusters were identified: one capturing all the candidate cultivars selected from various Sardinian localities, and the other wild individuals collected from Asinara, Corsica and Surigheddu. A moderate level of gene flow between the Sardinian and Corsican populations was identified. Discriminant analysis of principal components revealed a level of separation among the wild populations, confirming the population structure identified by the clustering methods. Conclusions: The wild accessions were well differentiated from the candidate cultivars. The level of genetic variability was high. The genetic data were compatible with the notion that myrtle has a mixed pollination system, including both out-pollination by insects and self-pollination. The candidate cultivars are suggested to represent an appropriate basis for directed breeding

    Detection on OAR7 of QTL affecting fat and protein yields in dairy sheep

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    The objective of this paper was identifying QTL that affect fat and protein yields in dairy sheep independently of milk yield. Data were collected in an experimental flock of 887 ewes organized in a daughter design. QTL detection focused on OAR7 where 13 microsatellites were available. The genetic abilities to produce fat and protein independently from the ability to produce milk were estimated as the residuals of the regression of EBV for fat and protein yields on EBV for milk yield. One QTL affecting fat yield (CWP=0.00009) and one QTL affecting protein yield (CWP=0.006) were detected. The most probable QTL location was 115.3 cM in the Sheep Best Position Linkage Map Version 4.7 for both traits. No QTL affecting milk yield was detected. The analysis of fat and protein yields independently of milk yield is an effective strategy to identify chromosomal regions affecting milk composition with no detrimental effect on milk yield

    A dedicated pipeline to analyse solar data with INAF radio telescopes: SUNPIT (SUNdish PIpeline Tool)

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    This technical note describes SUNPIT (SUNdish PIpeline Tool) - the pipeline aimed at the imaging procedure and the data analysis of the radio solar data - and guides the user to properly reduce and analyse the solar data. SUNPIT is designed for radio data acquired with some radio telescopes of the INAF Network: the Sardinia Radio Telescope (SRT), and the Medicina Radio Telescope. The present user manual follows the development of software for solar imaging and data analysis of Active Regions (ARs), performed in the framework of the INAF Proposal "SunDish Project" (PI: A. Pellizzoni). This project has been active since 2018 with the goal of monitoring the solar atmosphere at high radio frequencies (at present 18 - 26 GHz) through single-dish observations. These solar observations will be enhanced through the upgrading of SRT with the new cryogenically cooled receivers, including a 19-feed in Q-band (33 - 50 GHz) and a 16-feed in W-band (75 - 116 GHz), in the context of the National Operative Programme (Programma Operativo Nazionale-PON); this project will provide in the near future an upgrading with the new receivers up to 116 GHz also for the Medicina and Noto Radio Telescopes, to provide the scientific community with the instrumentation suited to the study of the Universe at high radio frequencies. SUNPIT will be suitable for the data of these new forthcoming receivers, when available for the scientific community. SUNPIT produces a complete analysis of a solar map in about one hour, saving a directory which contains images, plots and several tables with the physical information of the solar disk and ARs (brightness temperatures, fluxes and spectral indices, with the respective errors). This pipeline – successfully tested – represents a crucial tool (1) to analyse solar images observed with the radio telescopes of the INAF Network, and (2) for the Space Weather monitoring network and forecast (soon available) along the solar cycle

    Identification of cork characters for phenotypic selection

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    Global change effects can determine major changes in species distribution and productivity. In the Mediterranean region of the severity of hot and dry periods is growing and an increased frequency of extreme events and a major vulnerability of natural ecosystems is evident. Cork oak (Quercus suber L.) is widely spread in the West Mediterranean region and its economic and social is important

    Modelling high-resolution spatially-resolved Supernova Remnant spectra with the Sardinia Radio Telescope

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    Supernova Remnants (SNRs) exhibit spectra featured by synchrotron radio emission arising from the relativistic electrons, and high-energy emission from both leptonic (Bremsstrahlung and Inverse Compton) and hadronic processes (Ď€0 mesons decay) which are a direct signature of cosmic rays acceleration. Thanks to radio single-dish imaging observations obtained in three frequency bands (1.6, 7, 22 GHz) with the Sardinia Radio Telescope (www.srt.inaf.it), we can model different SNR regions separately. Indeed, in order to disentangle interesting and peculiar hadron contributions in the high-energy spectra (gamma-ray band) and better constrain SNRs as cosmic rays emitters, it is crucial to fully constrain lepton contributions first through radio-observed parameters. In particular, the Bremsstrahlung and Inverse Compton bumps observed in gamma-rays are bounded to synchrotron spectral slope and cut-off in the radio domain. Since these parameters vary for different SNR regions and electron populations, spatially-resolved radio spectra are then required for accurate multi-wavelength modelling
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