654 research outputs found

    Probing the ejecta of evolved massive stars in transition: A VLT/SINFONI K-band survey

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    Massive evolved stars in transition phases, such as Luminous Blue Variables (LBVs), B[e] Supergiants (B[e]SGs), and Yellow Hypergiants (YHGs), are not well understood, and yet crucial steps in determining accurate stellar and galactic evolution models. The circumstellar environments of these stars reveal their mass-loss history, identifying clues to both their individual evolutionary status and the connection between objects of different phases. Here we present a survey of 25 such evolved massive stars (16 B[e]SGs, 6 LBVs, 2 YHGs, and 1 Peculiar Oe star), observed in the K-band with the Spectrograph for INtegral Field Observation in the Near-Infrared (SINFONI; R = 4500) on the ESO VLT UT4 8 m telescope. The sample can be split into two categories based on spectral morphology: one group includes all of the B[e]SGs, the Peculiar Oe star, and two of the LBVs, while the other includes the YHGs and the rest of the LBVs. The difference in LBV spectral appearance is due to some objects being in a quiescent phase and some objects being in an active or outburst phase. CO emission features are found in 13 of our targets, with first time detections for MWC 137, LHA 120-S 35, and LHA 115-S 65. From model fits to the CO band heads, the emitting regions appear to be detached from the stellar surface. Each star with ^12CO features also shows ^13CO emission, signaling an evolved nature. Based on the level of ^13C enrichment, we conclude that many of the B[e]SGs are likely in a pre-Red Supergiant phase of their evolution. There appears to be a lower luminosity limit of log L/L_solar = 5.0 below which CO is not detected. The lack of CO features in several high luminosity B[e]SGs and variability in others suggests that they may in fact be LBV candidates, strengthening the connection between these two very similar transition phases.Comment: 20 pages, 13 figures, 7 tables. Accepted for publication in A&

    The activity of Pleurotus ostreatus extracts against pathogenic fusaria

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    A P. ostreatus strain, appreciated as food and for the production of nutraceuticals, was grown on a commercial substrate, dried at low temperature (<40\ub0C) and grinded in order to produce a mushroom powder. The bioactivity of the water extract conserved at 4\ub0C in the dark was then assessed on F. graminearum, F. culmorum and F. musae at different time points from production (4 hrs, 40 days, 4 months). Moreover, the effect of the extracts on trichothecene type B production was measured exploiting a F. graminearum isolate expressing GFP-tagged trichodiene synthase. This allowed to monitor the first step of toxin production using a microplate fluorimeter. While mycelial growth of F. graminearum and F. culmorum was completely blocked at 3 mg/ml, mycelial growth of F. musae was inhibited at 90%. MIC50 was measured for F. graminearum and F. culmorum at 300 micrograms/mL. A loss of the bioactivity of P. ostreaus water extract on fungal growth was observed at 40 days (-30%) and of a further -30% at 4 months. A preliminary study on the biological activities of the extract identified a strong protease activity associated to low molecular weight proteins. Their bioactivity decreased over storage time in accordance with a decreased proteolytic activity. The P. ostreatus extract modulates trichothecene production independently from the protease activity, even at concentration where no mycelium inhibition was observed (down to 0.75 micrograms/mL). Studies on the genetic determinants of the protease activity as well as the compounds able to modulate trichothecene production are ongoing

    The sudden appearance of CO emission in LHA 115-S 65

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    Molecular emission has been detected in several Magellanic Cloud B[e] supergiants. In this Letter, we report on the detection of CO band head emission in the B[e] supergiant LHA 115-S 65, and present a K-band near-infrared spectrum obtained with the Spectrograph for INtegral Field Observation in the Near-Infrared (SINFONI; R=4500) on the ESO VLT UT4 telescope. The observed molecular band head emission in S 65 is quite surprising in light of a previous non-detection by McGregor et al. 1989, as well as a high resolution (R=50000) Gemini/Phoenix spectrum of this star taken nine months earlier showing no emission. Based on analysis of the optical spectrum by Kraus et al. 2010, we suspect that the sudden appearance of molecular emission could be due to density build up in an outflowing viscous disk, as seen for Be stars. This new discovery, combined with variability in two other similar evolved massive stars, indicates an evolutionary link between B[e] supergiants and LBVs.Comment: Letter accepted for publication in MNRAS. 5 pages, 2 figures, 1 tabl

    Evidence of the evolved nature of the B[e] star MWC 137

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    The evolutionary phase of B[e] stars is difficult to establish due to the un certainties in their fundamental parameters. For instance, possible classications for the Galactic B[e] starMWC 137 include pre- main-sequence and post-main-sequence phases, with a large range in luminosity. Our goal is to clarify the evolutionary stage of this peculiar object, and to study the CO molecular component of its circumstellar medium. To this purpose, we modeled the CO molecular bands using high-resolution K-band spectra. We nd that MWC137 is surrounded by a detached cool (T = 1900100 K) and dense (N = (31)1021 cm2) ring of CO gas orbiting the star with a rotational velocity, projected to the line of sight, of 84 2 kms1. We also nd that the molec- ular gas is enriched in the isotope 13C, excluding the classication of the star as a Herbig Be. The observed isotopic abundance ratio (12C=13C = 25 2) derived from our modeling is compatible with a proto-PN, main-sequence or supergiant evolutionary phase. However, based on some observable characteristics of MWC137, we propose that the supergiant scenario seems to be the most plausible. Hence, we suggest that MWC137 could be in an extremely short-lived phase, evolving from a B[e] supergiant to a blue supergiant with a bipolar ring nebula.Fil: Muratore, M. F.. Universidad Nacional de la Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Astrofísica de La Plata; ArgentinaFil: Kraus, M.. Astronomický ústav; República ChecaFil: Oksala, M. E.. Astronomický ústav; República ChecaFil: Arias, María Laura. Universidad Nacional de la Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Astrofísica de La Plata; ArgentinaFil: Cidale, Lydia Sonia. Universidad Nacional de la Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Astrofísica de La Plata; ArgentinaFil: Borges Fernandes, M.. Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; BrasilFil: Liermann, A.. Leibniz-Institut für Astrophysik Potsdam; Alemani

    Fundamental parameters of B supergiants from the BCD system: I. Calibration of the (λ1, D) parameters into Teff

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    Context. Effective temperatures of early-type supergiants are important to test stellar atmosphere- and internal structure-models of massive and intermediate mass objects at different evolutionary phases. However, these Teff values are more or less discrepant depending on the method used to determine them. Aims. We aim to obtain a new calibration of the T eff parameter for early-type supergiants as a function of observational quantities that are: a) highly sensitive to the ionization balance in the photosphere and its gas pressure; b) independent of the interstellar extinction; c) as much as possible model-independent. Methods. The observational quantities that best address our aims are the (λ1, D) parameters of the BCD spectrophotometric system. They describe the energy distribution around the Balmer discontinuity, which is highly sensitive to Teff and log g. We perform a calibration of the (λ 1, D) parameters into Teff using effective temperatures derived with the bolometric-flux method for 217 program stars, whose individual uncertainties are on average |ΔTeff|/Teff f = 0.05. Results. We obtain a new and homogeneous calibration of the BCD (λ1, D) parameters for OB supergiants and revisit the current calibration of the (λ1, D) zone occupied by dwarfs and giants. The final comparison of calculated with obtained Teff values in the (λ1, D) calibration show that the latter have total uncertainties, which on average are εTeff/Teff f ≃ ±0.05 for all spectral types and luminosity classes. Conclusions. The effective temperatures of OB supergiants derived in this work agree on average within some 2000 K with other determinations found in the literature, except those issued from wind-free non-LTE plane-parallel models of stellar atmospheres, which produce effective temperatures that can be overestimated by up to more than 5000 K near Teff = K. Since the stellar spectra needed to obtain the (λ1, D) parameters are of low resolution, a calibration based on the BCD system is useful to study stars and stellar systems like open clusters, associations or stars in galaxies observed with multi-object spectrographs and/or spectro-imaging devices.Facultad de Ciencias Astronómicas y Geofísica

    Fundamental parameters of B supergiants from the BCD system: I. Calibration of the (λ1, D) parameters into Teff

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    Context. Effective temperatures of early-type supergiants are important to test stellar atmosphere- and internal structure-models of massive and intermediate mass objects at different evolutionary phases. However, these Teff values are more or less discrepant depending on the method used to determine them. Aims. We aim to obtain a new calibration of the T eff parameter for early-type supergiants as a function of observational quantities that are: a) highly sensitive to the ionization balance in the photosphere and its gas pressure; b) independent of the interstellar extinction; c) as much as possible model-independent. Methods. The observational quantities that best address our aims are the (λ1, D) parameters of the BCD spectrophotometric system. They describe the energy distribution around the Balmer discontinuity, which is highly sensitive to Teff and log g. We perform a calibration of the (λ 1, D) parameters into Teff using effective temperatures derived with the bolometric-flux method for 217 program stars, whose individual uncertainties are on average |ΔTeff|/Teff f = 0.05. Results. We obtain a new and homogeneous calibration of the BCD (λ1, D) parameters for OB supergiants and revisit the current calibration of the (λ1, D) zone occupied by dwarfs and giants. The final comparison of calculated with obtained Teff values in the (λ1, D) calibration show that the latter have total uncertainties, which on average are εTeff/Teff f ≃ ±0.05 for all spectral types and luminosity classes. Conclusions. The effective temperatures of OB supergiants derived in this work agree on average within some 2000 K with other determinations found in the literature, except those issued from wind-free non-LTE plane-parallel models of stellar atmospheres, which produce effective temperatures that can be overestimated by up to more than 5000 K near Teff = K. Since the stellar spectra needed to obtain the (λ1, D) parameters are of low resolution, a calibration based on the BCD system is useful to study stars and stellar systems like open clusters, associations or stars in galaxies observed with multi-object spectrographs and/or spectro-imaging devices.Facultad de Ciencias Astronómicas y Geofísica

    The Role of PET in the Diagnosis and Disease Activity Assessment in Large Vessel Vasculitis

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    The role of 18F-fluorodeoxyglucose (FDG) positron emission tomography (18F-FDG PET) in the diagnosis of large vessel vasculitis (LVV) is well established. It permits us to assess the extent and the grade of vascular involvement and to rule out the other causes in clinical scenarios characterized by less specific symptoms. The advantages of 18F-FDG PET are far less clear in monitoring disease activity over time. Studies looking for the role of 18F-FDG PET as a potential biomarker had conflicting results and whether and when to repeat it during follow-up is based on clinical experience. A comprehensive assessment, including clinical, laboratory and morphological imaging is still required to monitor patients with large-vessel vasculitis over time. The aim of this review is to present more recent data about the utility of 18 F-FDG PET in the diagnosis and follow-up of LVV

    SAT0461 SHORT-TERM MONITORING OF DENOSUMAB EFFECT IN BREAST CANCER PATIENTS RECEIVING AROMATASE INHIBITORS USING REMS TECHNOLOGY ON LUMBAR SPINE

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    Background:Aromatase inhibitor (AI) therapy in women with estrogen receptor-positive (ER+) breast cancer (BC) causes accelerated bone loss and increased risk of osteoporosis and fractures as side effects. Denosumab (i.e. 60 mg twice a year) is a viable therapy against bone resorption, but the short-term monitoring of bone mineral density (BMD) change with time is still an unmet clinical need, since the current techniques (including dual-energy X-ray absorptiometry, DXA) require 1-2 years between two consecutive measurements [1]. Radiofrequency Echographic Multi Spectrometry (REMS), with high performance in terms of precision and repeatability [2], might be used in this setting of patients for short-term monitoring of bone health-related parameters.Objectives:The objective is the short-term monitoring of the effect of AIs with/without denosumab on bone health in BC patients using REMS and DXA scans at lumbar spine.Methods:Post-menopausal ER+ BC patients treated with adjuvant AIs were recruited. Two subgroups were identified, whether receiving also 60 mg of denosumab therapy every 6 months or not (named Group A and Group B, respectively). All patients underwent baseline DXA and REMS lumbar spine scans at time T0, previous to the first AI therapy, and after 12 months (time T1). REMS scan only was repeated also at 18 months (T2), since a 6-month interval between two consecutive scans is not recommended for DXA. The bone mineral density (BMD) was measured with both techniques.Results:Overall, 254 ER+ BC patients were enrolled (127 per group). The effect of denosumab on BMD is reported in Table. The BMD values obtained by DXA and REMS were not significantly different at T0 and T1, whereas the difference between Group A and B at T1 was statistically significant (p<0.001) both for REMS and DXA. At T2, REMS confirmed the increasing trend of BMD for Group A and the decreasing one for Group B, and the difference between groups was statistically significant (p<0.001). For each time point and each group, there were not statistically significant differences between DXA and REMS.Conclusion:Several studies have shown the effect of denosumab on BMD over a period not less than 2 years from the start of treatment. This study showed the feasibility of short-term follow-up using REMS lumbar spine scans at 6-month time steps.References:[1]Diez-Perez A et al, Aging Clin Exp Res 2019;31(10):1375–89[2]Di Paola M et al, Osteoporos Int 2018;30:391–402Table 1.BMD values, expressed as g/cm2, measured by DXA and REMS for Group A (patients receiving AIs only) and Group B (patients receiving AIs and denosumab) at baseline (T0), 12 months (T1) and 18 months (T2) from the start of therapy. Results are presented as median values with 25thand 75thpercentiles. P-values are obtained with a Mann-Whitney test.DXAREMSScan timeGroup AGroup BpGroup AGroup BpT00.840 (0.719-0.959)0.867 (0.723-0.958)0.990.833 (0.708-0.949)0.855 (0.714-0.973)0.77T10.823 (0.702-0.944)0.889 (0.749-0.990)0.0030.819 (0.691-0.927)0.887 (0.740-1.018)<0.001T2---0.801 (0.679-0.909)0.899 (0.754-1.020)<0.001Note:The authorsD. Ciardo, M. Ciccarese, F. Conversano, M. Di Paola, R. Forcignanò, A. Grimaldi, F.A. Lombardi, M. Muratore and P. Pisaniare listed in alphabetical orderDisclosure of Interests:None declare

    Health-related quality of life in breast cancer patients treated with CDK4/6 inhibitors: a systematic review

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    Background: Evaluation of health-related quality of life (HR-QoL) among cancer patients has gained an increasing importance and is now a key determinant of anticancer treatments’ value. HR-QoL has been assessed in trials testing cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) in breast cancer (BC), using various questionnaires at different timepoints. HR-QoL reports from BC patients treated with CDK4/6i in the real-world setting are also available. Methods: We systematically reviewed the literature, searching for full-length articles, and selected conference abstracts reporting data on HR-QoL in BC patients at any stage and of any molecular subtype treated with abemaciclib, palbociclib or ribociclib. Results: A total of 533 full-length articles and 143 abstracts were retrieved. After screening for eligibility, 38 records were included (31 clinical trials; 7 real-world reports). Assessment methods were heterogeneous across studies in terms of questionnaires, evaluation timepoints and endpoints. Overall, adding CDK4/6i to endocrine therapy did not worsen patients’ HR-QoL, with a positive trend towards pain improvement. Gastrointestinal scores (diarrhea, nausea and appetite loss) statistically favored the control arm among metastatic BC patients receiving abemaciclib, whereas they were superimposable in the early setting. The combination of palbociclib and endocrine therapy showed similar HR-QoL outcomes compared with endocrine therapy alone, but determined better scores compared with chemotherapy. HR-QoL was specifically assessed in premenopausal patients treated with ribociclib, showing similar scores compared with postmenopausal patients. Conclusions: Despite methodological heterogeneity does not allow a proper comparison, HR-QoL was generally maintained with CDK4/6i. However, differences between abemaciclib, palbociclib and ribociclib exist and mainly rely on the distinct safety profiles of the compounds. These differences should be acknowledged and taken into account in the clinical practice

    Molecular emission from GG Carinae's circumbinary disk

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    The appearance of the B[e] phenomenon in evolved massive stars such as B[e] supergiants is still a mystery. While these stars are generally found to have disks that are cool and dense enough for efficient molecule and dust condensation, the origin of the disk material is still unclear. We aim at studying the kinematics and origin of the disk in the eccentric binary system GG Car, whose primary component is proposed to be a B[e] supergiant. Based on medium- and high-resolution near-infrared spectra we analyzed the CO-band emission detected from GG Car. The complete CO-band structure delivers information on the density and temperature of the emitting region, and the detectable 13CO bands allow us to constrain the evolutionary phase. In addition, the kinematics of the CO gas can be extracted from the shape of the first 12CO band head. We find that the CO gas is located in a ring surrounding the eccentric binary system, and its kinematics agrees with Keplerian rotation with a velocity, projected to the line of sight, of (80pm 1) km/s. The CO ring has a column density of (5pm 3)x10^21 cm^-2 and a temperature of 3200pm 500 K. In addition, the material is chemically enriched in 13CO, which agrees with the primary component being slightly evolved off the main sequence. We discuss two possible scenarios for the origin of the circumbinary disk: (i) non-conservative Roche lobe overflow, and (ii) the possibility that the progenitor of the primary component could have been a classical Be star. Neither can be firmly excluded, but for Roche lobe overflow to occur, a combination of stellar and orbital parameter extremawould be required.Fil: Kraus, M.. Astronomický ústav; República ChecaFil: Oksala, M. E.. Astronomický ústav; República ChecaFil: Nickeler, D. H.. Astronomický ústav; República ChecaFil: Muratore, M. F.. Universidad Nacional de la Plata. Facultad de Ciencias Astronómicas y Geofísicas; ArgentinaFil: Borges Fernandes, M.. Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; BrasilFil: Aret, A.. Tartu Observatory; EstoniaFil: Cidale, Lydia Sonia. Universidad Nacional de la Plata. Facultad de Ciencias Astronómicas y Geofísicas; ArgentinaFil: de Wit, W. J.. European Southern Observatory; Chil
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