78 research outputs found

    Intraocular Metastases Secondary to Breast Carcinoma Correlates With Upregulation of Estrogen and Progesterone Receptor Expression in the Primary Tumor

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    To compare estrogen (ER), progesterone (PR), and human epidermal growth factor-2 (HER2) receptor expression in the primary tumor of patients affected by choroidal metastases from breast carcinoma (BC) versus those with extraocular metastases

    Long-term follow-up of Philadelphia chromosome-positive (Ph+) chronic myeloid leukaemia (CML) in children and adolescents managed at a single institution over a 20-year period

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    Chronic myeloid leukaemia (CML) is rare in childhood. In our Institution we managed 30 consecutive Ph+CML patients aged <18 years, according to our adults’ guidelines. Patients with HLA-identical related donor (RD) underwent stem cell transplant (SCT). Since 1989, patients without RD were systematically treated with -interferon (IFN) (median dosage: 6 MU/day). Of 18/19 evaluable patients, 17 (94.5%) achieved haematologic response (HR), 11/17 (65%) cytogenetic response (CyR), complete (CCyR) in 4 (23.5%). Three patients remain in CCyR, 2 achieved BCR-ABL transcript disappearance. Of 13 patients without CCyR, 5 underwent SCT, 4 switched to STI571, 4 progressed. All patients receiving STI571 in chronic phase (CP) obtained sustained CCyR and 3 a persistent molecular response. 8-year survival among IFN-treated patients, censored or not for subsequent therapies, is 62% and 63%. Overall, 13/30 patients underwent SCT: 5 HLA-identical-RD, 5 matched unrelated donor, 2 mismatched-RD, 1 unrelated mismatched umbilical cord blood. Eight allotransplanted patients (6/6 in 1st CP) are in cytogenetic and molecular remission with 8-year survival of 61% from SCT and 69% from diagnosis. In our 20-year experience, the use of IFN in children without matched RD led to prolonged cytogenetic and molecular responses and long-term survival, without impairing the outcome of subsequent SCT

    Constraints from Dust Mass and Mass Accretion Rate Measurements on Angular Momentum Transport in Protoplanetary Disks

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    We investigate the relation between disk mass and mass accretion rate to constrain the mechanism of angular momentum transport in protoplanetary disks. Dust mass and mass accretion rate in Chamaeleon I are correlated with a slope close to linear, similar to the one recently identified in Lupus. We investigate the effect of stellar mass and find that the intrinsic scatter around the best-fit Mdust-Mstar and Macc-Mstar relations is uncorrelated. Disks with a constant alpha viscosity can fit the observed relations between dust mass, mass accretion rate, and stellar mass, but over-predict the strength of the correlation between disk mass and mass accretion rate when using standard initial conditions. We find two possible solutions. 1) The observed scatter in Mdust and Macc is not primoridal, but arises from additional physical processes or uncertainties in estimating the disk gas mass. Most likely grain growth and radial drift affect the observable dust mass, while variability on large time scales affects the mass accretion rates. 2) The observed scatter is primordial, but disks have not evolved substantially at the age of Lupus and Chamaeleon I due to a low viscosity or a large initial disk radius. More accurate estimates of the disk mass and gas disk sizes in a large sample of protoplanetary disks, either through direct observations of the gas or spatially resolved multi-wavelength observations of the dust with ALMA, are needed to discriminate between both scenarios or to constrain alternative angular momentum transport mechanisms such as MHD disk winds.Comment: See also the paper by Lodato et a

    The evolution of dust-disk sizes from a homogeneous analysis of 1-10 Myr-old stars

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    We utilize ALMA archival data to estimate the dust disk size of 152 protoplanetary disks in Lupus (1-3 Myr), Chamaeleon I (2-3 Myr), and Upper-Sco (5-11 Myr). We combine our sample with 47 disks from Tau/Aur and Oph whose dust disk radii were estimated, as here, through fitting radial profile models to visibility data. We use these 199 homogeneously derived disk sizes to identify empirical disk-disk and disk-host property relations as well as to search for evolutionary trends. In agreement with previous studies, we find that dust disk sizes and millimeter luminosities are correlated, but show for the first time that the relationship is not universal between regions. We find that disks in the 2-3 Myr-old Cha I are not smaller than disks in other regions of similar age, and confirm the Barenfeld et al. (2017) finding that the 5-10 Myr USco disks are smaller than disks belonging to younger regions. Finally, we find that the outer edge of the Solar System, as defined by the Kuiper Belt, is consistent with a population of dust disk sizes which have not experienced significant truncation.Comment: ApJ accepted, 38 pages, 16 figures, 68k compatibl

    An ALMA Survey of CO isotopologue emission from Protoplanetary Disks in Chamaeleon I

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    The mass of a protoplanetary disk limits the formation and future growth of any planet. Masses of protoplanetary disks are usually calculated from measurements of the dust continuum emission by assuming an interstellar gas-to-dust ratio. To investigate the utility of CO as an alternate probe of disk mass, we use ALMA to survey 13^{13}CO and C18^{18}O J = 3−23-2 line emission from a sample of 93 protoplanetary disks around stars and brown dwarfs with masses from 0.03 -- 2 M⊙_{\odot} in the nearby Chamaeleon I star-forming region. We detect 13^{13}CO emission from 17 sources and C18^{18}O from only one source. Gas masses for disks are then estimated by comparing the CO line luminosities to results from published disk models that include CO freeze-out and isotope-selective photodissociation. Under the assumption of a typical ISM CO-to-H2_2 ratios of 10−410^{-4}, the resulting gas masses are implausibly low, with an average gas mass of ∌\sim 0.05 MJup_{Jup} as inferred from the average flux of stacked 13^{13}CO lines. The low gas masses and gas-to-dust ratios for Cha I disks are both consistent with similar results from disks in the Lupus star-forming region. The faint CO line emission may instead be explained if disks have much higher gas masses, but freeze-out of CO or complex C-bearing molecules is underestimated in disk models. The conversion of CO flux to CO gas mass also suffers from uncertainties in disk structures, which could affect gas temperatures. CO emission lines will only be a good tracer of the disk mass when models for C and CO depletion are confirmed to be accurate.Comment: accepted for publication in Ap

    A 1.3 mm SMA Survey of 29 Variable Young Stellar Objects

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    © 2018 ESO. Reproduced with permission from Astronomy & Astrophysics.Context. Young stellar objects (YSOs) may undergo periods of active accretion (outbursts), during which the protostellar accretion rate is temporarily enhanced by a few orders of magnitude. Whether or not these accretion outburst YSOs possess similar dust and gas reservoirs to each other, and whether or not their dust and gas reservoirs are similar as quiescent YSOs, are issues yet to be clarified.Aims. The aim of this work is to characterize the millimeter thermal dust emission properties of a statistically significant sample of long and short duration accretion outburst YSOs (i.e., FUors and EXors) and the spectroscopically identified candidates of accretion outbursting YSOs (i.e., FUor-like objects). Methods. We have carried out extensive Submillimeter Array (SMA) observations mostly at ~225 GHz (1.33 mm) and ~272 GHz (1.10 mm), from 2008 to 2017. We covered accretion outburst YSOs located at 3σ significance. Detected sources except for the two cases of V883 Ori and NGC 2071 MM3 were observed with ~1″ angular resolution. Overall our observed targets show a systematically higher millimeter luminosity distribution than those of the M ∗ > 0.3 MClass II YSOs in the nearby (400 pc) low-mass star-forming molecular clouds (e.g., Taurus, Lupus, Upp Scorpio, and Chameleon I). In addition, at 1 mm our observed confirmed binaries or triple-system sources are systematically fainter than the rest of the sources even though their 1 mm fluxes are broadly distributed. We may have detected ∌30-60% millimeter flux variability from V2494 Cyg and V2495 Cyg, from the observations separated by approximately one year.Peer reviewe

    Disk Imaging Survey of Chemistry with SMA (DISCS): I. Taurus Protoplanetary Disk Data

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    Chemistry plays an important role in the structure and evolution of protoplanetary disks, with implications for the composition of comets and planets. This is the first of a series of papers based on data from DISCS, a Submillimeter Array survey of the chemical composition of protoplanetary disks. The six Taurus sources in the program (DM Tau, AA Tau, LkCa 15, GM Aur, CQ Tau and MWC 480) range in stellar spectral type from M1 to A4 and offer an opportunity to test the effects of stellar luminosity on the disk chemistry. The disks were observed in 10 different lines at ~3" resolution and an rms of ~100 mJy beam-1 at ~0.5 km s-1. The four brightest lines are CO 2-1, HCO+ 3-2, CN 2_3-1_2 and HCN 3-2 and these are detected toward all sources (except for HCN toward CQ Tau). The weaker lines of CN 2_2-1_1, DCO+ 3-2, N2H+ 3-2, H2CO 3_03-2_02 and 4_14-3_13 are detected toward two to three disks each, and DCN 3-2 only toward LkCa 15. CH3OH 4_21-3_12 and c-C3H2 are not detected. There is no obvious difference between the T Tauri and Herbig Ae sources with regard to CN and HCN intensities. In contrast, DCO+, DCN, N2H+ and H2CO are detected only toward the T Tauri stars, suggesting that the disks around Herbig Ae stars lack cold regions for long enough timescales to allow for efficient deuterium chemistry, CO freeze-out, and grain chemistry.Comment: 29 pages, 4 figures, accepted for publication in Ap

    Constraints on photoevaporation models from (lack of) radio emission in the Corona Australis protoplanetary disks

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    R. GalvĂĄn-Madrid, et al., “Constraints on photoevaporation models from (lack of) radio emission in the Corona Australis protoplanetary disks”, Astronomy & Astrophysics, Vol. 570, October 2014. This version of record is available online at: https://doi.org/10.1051/0004-6361/201424630 Reproduced with Permission from Astronomy and Astrophysics, © ESO 2014.Photoevaporation due to high-energy stellar photons is thought to be one of the main drivers of protoplanetary disk dispersal. The fully or partially ionized disk surface is expected to produce free-free continuum emission at centimeter (cm) wavelengths that can be routinely detected with interferometers such as the upgraded Very Large Array (VLA). We use deep (rms noise down to 8 ÎŒ\muJy beam−1^{-1} in the field of view center) 3.5 cm maps of the nearby (130 pc) Corona Australis (CrA) star formation (SF) region to constrain disk photoevaporation models. We find that the radio emission from disk sources in CrA is surprisingly faint. Only 3 out of 10 sources within the field of view are detected, with flux densities of order 10210^2 ÎŒ\muJy. However, a significant fraction of their emission is non-thermal. Typical upper limits for non-detections are 3σ∌60 Ό3\sigma\sim 60~\muJy beam−1^{-1}. Assuming analytic expressions for the free-free emission from extreme-UV (EUV) irradiation, we derive stringent upper limits to the ionizing photon luminosity impinging on the disk surface $\Phi_\mathrm{EUV}Peer reviewe
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