120 research outputs found

    New insights into the use of Ultra Long Period Cepheids as cosmological standard candles

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    Ultra Long Period Cepheids (ULPs) are pulsating variable stars with a period longer than 80d and have been hypothesized to be the extension of the Classical Cepheids (CCs) at higher masses and luminosities. If confirmed as standard candles, their intrinsic luminosities, 1 to 3 mag brighter than typical CCs, would allow to reach the Hubble flow and, in turn, to determine the Hubble constant, H_0, in one step, avoiding the uncertainties associated with the calibration of primary and secondary indicators. To investigate the accuracy of ULPs as cosmological standard candles, we first collect all the ULPs known in the literature. The resulting sample includes 63 objects with a very large metallicity spread with 12 + log([O/H]) ranging from 7.2 to 9.2 dex. The analysis of their properties in the VI period-Wesenheit plane and in the color-magnitude diagram (CMD) supports the hypothesis that the ULPs are the extension of CCs at longer periods, higher masses and luminosities, even if, additional accurate and homogeneous data and a devoted theoretical scenario are needed to get firm conclusions. Finally, the three M31 ULPs, 8-0326, 8-1498 and H42, are investigated in more detail. For 8-1498 and H42, we cannot confirm their nature as ULPs, due to the inconsistency between their position in the CMD and the measured periods. For 8-0326, the light curve model fitting technique applied to the available time-series data allows us to constrain its intrinsic stellar parameters, distance and reddening.Comment: MNRAS - Accepted 2020 November 19. Received 2020 November 19; in original form 2020 July 15 - 9 pages and 8 figure

    HIV-1 Integrase Inhibition Activity by Spiroketals Derived from Plagius flosculosus, an Endemic Plant of Sardinia (Italy) and Corsica (France)

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    In this work we investigated, for the first time, the effect of Plagius flosculosus (L.) Alavi & Heywood, a Sardinian–Corsican endemic plant, on HIV-1 integrase (IN) activity. The phytochemical analysis of the leaves chloroform extract led us to isolate and characterize three compounds (SPK1, SPK2, and SPK3) belonging to the spiroketals, a group of naturally occurring metabolites of phytochemical relevance with interesting biological properties. Due to their structural diversity, these cyclic ketals have attracted the interest of chemists and biologists. SPK1, SPK2, and SPK3 were evaluated here for their ability to inhibit HIV-1 integrase activity in biochemical assays. The results showed that all the compounds inhibited HIV-1 IN activity. In particular, the most active one was SPK3, which interfered in a low molecular range (IC50 of 1.46 ± 0.16 µM) with HIV-1 IN activity in the presence/absence of the LEDGF cellular cofactor. To investigate the mechanism of action, the three spiroketals were also tested on HIV-1 RT-associated Ribonuclease H (RNase H) activity, proving to be active in inhibiting this function. Although SPK3 was unable to inhibit viral replication in cell culture, it promoted the IN multimerization. We hypothesize that SPK3 inhibited HIV-1 IN through an allosteric mechanism of action

    Immunological backbone of uveal melanoma: is there a rationale for immunotherapy?

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    No standard treatment has been established for metastatic uveal melanoma (mUM). Immunotherapy is commonly used for this disease even though UM has not been included in phase III clinical trials with checkpoint inhibitors. Unfortunately, only a minority of patients obtain a clinical benefit with immunotherapy. The immunological features of mUM were reviewed in order to understand if immunotherapy could still play a role for this disease

    Isolated ovarian follicle culture: a promising strategy for fertility preservation

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    Ovarian tissue cryopreservation represents one among the most preferred strategies for fertility preservation currently. However, concerns regarding the transmission of malignant cells during the transplantion of stored ovarian tissues, is a major restraint in recommending the procedure to patients diagnosed with all kinds of malignant disorders. On the contrary, use of isolated follicles for restoration of fertility in such patients could completely evade the possibility of cancer re-introduction after treatment. Follicles housed in the ovarian environment in vivo prevail under the mechanical and the chemical/nutritional support of the ovary. Although not complete, recent knowledge about the dynamics of follicular progression has led to improvements in the culture system adopted. This review aims at summarising the culture of isolated follicles in vitro, particularly emphasising the efforts made to mechanically and nutritionally support the follicle. Advances in follicular culture systems could prove useful to highly improve the efficiency of current fertility restoration strategies and evade the concerns associated with the same

    Disease awareness in patients with COPD: measurement and extent

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    Background: Patient awareness of COPD refers to knowledge and acceptance of the disease and its treatment. Although it is relevant to management and outcomes, the disease awareness of patients is poorly investigated, and no validated questionnaires are currently available. We aimed to develop the novel Disease Awareness in COPD Questionnaire (DACQ), which was validated in relation to demographic and clinical features, in patients participating in the SATisfaction and Adherence to COPD Treatment (SAT) study. Methods: DACQ was developed according to a list of items regarding the patient's knowledge, acceptance, and perception of COPD as well as of treatment needs. The questionnaire was validated by assessing internal structure and consistency, correlations with other patient-reported outcomes, and stability over time. Furthermore, the extent of disease awareness of patients enrolled in the SAT study was assessed by using DACQ, and correlations with demographic and clinical features were evaluated. Results: DACQ was composed of four domains. Overall reliability and stability over time were adequate; correlations between DACQ and other tools measuring different constructs (ie, treatment satisfaction, illness perception, impact of COPD symptoms on daily life, and dyspnea severity) were, as expected, more limited. In the enrolled patient sample, a suboptimal level of disease awareness (<70%) was detected, especially in terms of disease acceptance and perception. Disease knowledge was positively associated with COPD severity, while the impact of symptoms on daily life was negatively associated with disease acceptance, awareness of treatment needs, and overall awareness. Conclusion: DACQ proved to be a reliable tool to assess awareness in COPD patients. Awareness of COPD patients need to be improved. Clinical trial registration: ClinicalTrials.gov ID# NCT02689492

    Theoretical Cepheid Period-Luminosity And Period-Color Relations In Spitzer IRAC Bands

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    In this paper the synthetic period-luminosity (P-L) relations in Spitzer's IRAC bands, based on a series of theoretical pulsation models with varying metal and helium abundance, were investigated. Selected sets of these synthetic P-L relations were compared to the empirical IRAC band P-L relations recently determined from Galactic and Magellanic Clouds Cepheids. For the Galactic case, synthetic P-L relations from model sets with (Y = 0.26, Z = 0.01), (Y = 0.26, Z = 0.02) and (Y = 0.28, Z = 0.02) agree with the empirical Galactic P-L relations derived from the Hubble Space Telescope parallaxes. For Magellanic Cloud Cepheids, the synthetic P-L relations from model sets with (Y = 0.25, Z = 0.008) agree with both of the empirical Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC) P-L relations. Analysis of the synthetic P-L relations from all model sets suggested that the IRAC band P-L relations may not be independent of metallicity, as the P-L slopes and intercepts could be affected by the metallicity and/or helium abundance. We also derive the synthetic period color(P-C) relations in the IRAC bands. Non-vanishing synthetic P-C relations were found for certain combinations of IRAC band filters and metallicity. However, the synthetic P-C relations disagreed with the [3.6]-[8.0] P-C relation recently found for the Galactic Cepheids. The synthetic [3.6]-[4.5] P-C slope from (Y = 0.25, Z = 0.008) model set, on the other hand, is in excellent agreement to the empirical LMC P-C counterpart, if a period range of 1.0 < log(P) < 1.8 is adopted.Comment: 13 pages, 14 figures and 5 tables, ApJ accepte

    Improving the conservation of Mediterranean Chondrichthyans : the ELASMOMED DNA barcode reference library

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    Cartilaginous fish are particularly vulnerable to anthropogenic stressors and environmental change because of their K-selected reproductive strategy. Accurate data from scientific surveys and landings are essential to assess conservation status and to develop robust protection and management plans. Currently available data are often incomplete or incorrect as a result of inaccurate species identifications, due to a high level of morphological stasis, especially among closely related taxa. Moreover, several diagnostic characters clearly visible in adult specimens are less evident in juveniles. Here we present results generated by the ELASMOMED Consortium, a regional network aiming to sample and DNA-barcode the Mediterranean Chondrichthyans with the ultimate goal to provide a comprehensive DNA barcode reference library. This library will support and improve the molecular taxonomy of this group and the effectiveness of management and conservation measures. We successfully barcoded 882 individuals belonging to 42 species (17 sharks, 24 batoids and one chimaera), including four endemic and several threatened ones. Morphological misidentifications were found across most orders, further confirming the need for a comprehensive DNA barcoding library as a valuable tool for the reliable identification of specimens in support of taxonomist who are reviewing current identification keys. Despite low intraspecific variation among their barcode sequences and reduced samples size, five species showed preliminary evidence of phylogeographic structure. Overall, the ELASMOMED initiative further emphasizes the key role accurate DNA barcoding libraries play in establishing reliable diagnostic species specific features in otherwise taxonomically problematic groups for biodiversity management and conservation actions.peer-reviewe

    Aquaporin-9 Contributes to the Maturation Process and Inflammatory Cytokine Secretion of Murine Dendritic Cells

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    Dendritic cells (DCs) are the most potent antigen-presenting cells able to trigger the adaptive immune response to specific antigens. When non-self-antigens are captured, DCs switch from an “immature” to a “mature” state to fulfill their function. Among the several surface proteins involved in DCs maturation, the role of aquaporins (AQPs) is still poorly understood. Here we investigated the expression profile of Aqps in murine bone marrow derived dendritic cells (BMDCs). Among the Aqps analyzed, Aqp9 was the most expressed by DCs. Its expression level was significantly upregulated 6 h following LPS exposure. Chemical inhibition of Aqp9 led to a decreased inflammatory cytokines secretion. BMDCs from AQP9-KO mice release lower amount of inflammatory cytokines and chemokines and increased release of IL-10. Despite the reduced release of inflammatory cytokines, Aqp9-KO mice were not protected from DSS induced colitis. All together, our data indicate that AQP9 blockade can be an efficient strategy to reduce DCs inflammatory response but it is not sufficient to protect from acute inflammatory insults such as DSS induced colitis
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