80 research outputs found
Intraocular Metastases Secondary to Breast Carcinoma Correlates With Upregulation of Estrogen and Progesterone Receptor Expression in the Primary Tumor
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
Chronic myeloid leukaemia (CML) is rare in childhood. In our Institution we managed 30 consecutive Ph+CML patients aged <18 years, according to our adultsâ 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
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
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
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 CO and CO J = line
emission from a sample of 93 protoplanetary disks around stars and brown dwarfs
with masses from 0.03 -- 2 M in the nearby Chamaeleon I star-forming
region. We detect CO emission from 17 sources and CO 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-H ratios of , the resulting gas masses are implausibly low,
with an average gas mass of 0.05 M as inferred from the average
flux of stacked 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
© 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 3Ï significance. Detected sources except for the two cases of V883 Ori and NGC 2071 MM3 were observed with ~1âł angular resolution. Overall our observed targets show a systematically higher millimeter luminosity distribution than those of the M â > 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 âŒ30-60% 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
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
R. GalvĂĄn-Madrid, et al., âConstraints on photoevaporation models from (lack of) radio emission in the Corona Australis protoplanetary disksâ, 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 Jy beam 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 Jy. However, a significant fraction of their emission is non-thermal. Typical upper limits for non-detections are Jy beam. 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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