992 research outputs found
Importance of Primary Indications for Fetal Echocardiography Proposed by the Portuguese Health Department
Introdução: A malformação congénita mais frequente é a cardíaca, afectando cerca de 5-8 recém-nascidos/mil nados vivos. Actualmente é possível obter um diagnóstico pré-natal destas anomalias através do ecocardiograma fetal (EcoF), porém, porque os recursos em Saúde são limitados, este exame deve ser pedido de acordo com os critérios estabelecidos pela Direcção Geral de Saúde (DGS).
Objectivos: Avaliar a importância dos critérios de referenciação propostos pela DGS para detecção de anomalias cardíacas. Determinar as taxas de prevalência e mortalidade nos fetos com doença cardíaca.
Material e Métodos: Revisão casuística de uma amostra de 733 fetos aos quais foi realizado EcoF em consulta de Cardiologia Pré-natal num centro terciário de Cardiologia Pediátrica, no período de 2006 a 2008. Foram avaliados dados demográficos, motivo de referenciação (MR), resultados da EcoF e evolução. Classificámos os MR em dois grupos: (I) concordantes com as indicações da DGS- causas major (familiar, materna, fetal) e causas minor (outras situações);
(II) não concordantes.
Resultados: Realizaram-se 871 EcoF a 705 grávidas. A mediana da idade materna foi de 32 anos (15-45 anos) e a média da idade gestacional foi de 26 semanas (±4 sem). O grupo I incluiu 89% das grávidas. Identificaram-se 52 fetos (7%) com anomalias cardíacas: 42 estruturais, 8 de ritmo e 2 derrames pericárdicos. Estas anomalias distribuíram-se da seguinte forma:
grupo I - causa familiar (3), causa materna (3), causa fetal (39), causas minor (5) e no
grupo II (2). Observou-se um maior número de anomalias cardíacas no grupo I (6,8% vs 0,3%)
(p> 0.05), sobretudo nos fetos referenciados por causa fetal (p<0,05). Perderam-se no controlo evolutivo 10 casos positivos, realizaram-se 3 interrupções médicas da gravidez e ocorreram 3 mortes. Mantêm-se em seguimento na consulta de Cardiologia Pediátrica 11 casos positivos.
Conclusões: Na maioria dos casos cumpriram-se os critérios de referenciação da DGS, no
entanto não se observou uma diferença estatisticamente significativa na prevalência de anomalias cardíacas fetais nas grávidas com e sem factores de risco. A causa fetal foi a que melhor se correlacionou com a presença de anomalia cardíaca. A prevalência destas anomalias e a
taxa de mortalidade aferida na amostra pode estar subestimada por perda de casos positivos no controlo evolutivo
In situ magnetic separation of antibody fragments from Escherichia coli in complex media.
BACKGROUND: In situ magnetic separation (ISMS) has emerged as a powerful tool to overcome process constraints such as product degradation or inhibition of target production. In the present work, an integrated ISMS process was established for the production of his-tagged single chain fragment variable (scFv) D1.3 antibodies ("D1.3") produced by E. coli in complex media. This study investigates the impact of ISMS on the overall product yield as well as its biocompatibility with the bioprocess when metal-chelate and triazine-functionalized magnetic beads were used. RESULTS: Both particle systems are well suited for separation of D1.3 during cultivation. While the triazine beads did not negatively impact the bioprocess, the application of metal-chelate particles caused leakage of divalent copper ions in the medium. After the ISMS step, elevated copper concentrations above 120 mg/L in the medium negatively influenced D1.3 production. Due to the stable nature of the model protein scFv D1.3 in the biosuspension, the application of ISMS could not increase the overall D1.3 yield as was shown by simulation and experiments. CONCLUSIONS: We could demonstrate that triazine-functionalized beads are a suitable low-cost alternative to selectively adsorb D1.3 fragments, and measured maximum loads of 0.08 g D1.3 per g of beads. Although copper-loaded metal-chelate beads did adsorb his-tagged D1.3 well during cultivation, this particle system must be optimized by minimizing metal leakage from the beads in order to avoid negative inhibitory effects on growth of the microorganisms and target production. Hereby, other types of metal chelate complexes should be tested to demonstrate biocompatibility. Such optimized particle systems can be regarded as ISMS platform technology, especially for the production of antibodies and their fragments with low stability in the medium. The proposed model can be applied to design future ISMS experiments in order to maximize the overall product yield while the amount of particles being used is minimized as well as the number of required ISMS steps
Efeito de agentes coadjuvantes na preservação das caracteristicas físico-químicas de maçãs cv. Fuji minimamente processadas.
False positive probabilties for all Kepler Objects of Interest: 1284 newly validated planets and 428 likely false positives
We present astrophysical false positive probability calculations for every
Kepler Object of Interest (KOI)---the first large-scale demonstration of a
fully automated transiting planet validation procedure. Out of 7056 KOIs, we
determine that 1935 have probabilities <1% to be astrophysical false positives,
and thus may be considered validated planets. 1284 of these have not yet been
validated or confirmed by other methods. In addition, we identify 428 KOIs
likely to be false positives that have not yet been identified as such, though
some of these may be a result of unidentified transit timing variations. A side
product of these calculations is full stellar property posterior samplings for
every host star, modeled as single, binary, and triple systems. These
calculations use 'vespa', a publicly available Python package able to be easily
applied to any transiting exoplanet candidate.Comment: 20 pages, 8 figures. Published in ApJ. Instructions to reproduce
results can be found at https://github.com/timothydmorton/koi-fp
Planet Hunters: Assessing the Kepler Inventory of Short Period Planets
We present the results from a search of data from the first 33.5 days of the
Kepler science mission (Quarter 1) for exoplanet transits by the Planet Hunters
citizen science project. Planet Hunters enlists members of the general public
to visually identify transits in the publicly released Kepler light curves via
the World Wide Web. Over 24,000 volunteers reviewed the Kepler Quarter 1 data
set. We examine the abundance of \geq 2 R\oplus planets on short period (< 15
days) orbits based on Planet Hunters detections. We present these results along
with an analysis of the detection efficiency of human classifiers to identify
planetary transits including a comparison to the Kepler inventory of planet
candidates. Although performance drops rapidly for smaller radii, \geq 4
R\oplus Planet Hunters \geq 85% efficient at identifying transit signals for
planets with periods less than 15 days for the Kepler sample of target stars.
Our high efficiency rate for simulated transits along with recovery of the
majority of Kepler \geq 4 R\oplus planets suggest suggests the Kepler inventory
of \geq 4 R\oplus short period planets is nearly complete.Comment: 41 pages,13 figures, 8 tables, accepted to Ap
Starspot Jitter in Photometry, Astrometry and Radial Velocity Measurements
Analytical relations are derived for the amplitude of astrometric,
photometric and radial velocity perturbations caused by a single rotating spot.
The relative power of the star spot jitter is estimated and compared with the
available data for Ceti and HD 166435, as well as with numerical
simulations for Ceti and the Sun. A Sun-like star inclined at
i=90\degr at 10 pc is predicted to have a RMS jitter of 0.087 \uas in its
astrometric position along the equator, and 0.38 m s in radial
velocities. If the presence of spots due to stellar activity is the ultimate
limiting factor for planet detection, the sensitivity of SIM Lite to Earth-like
planets in habitable zones is about an order of magnitude higher that the
sensitivity of prospective ultra-precise radial velocity observations of nearby
stars.Comment: accepted in ApJ Letters, Nov. 200
On planetary mass determination in the case of super-Earths orbiting active stars. The case of the CoRoT-7 system
This investigation uses the excellent HARPS radial velocity measurements of
CoRoT-7 to re-determine the planet masses and to explore techniques able to
determine mass and elements of planets discovered around active stars when the
relative variation of the radial velocity due to the star activity cannot be
considered as just noise and can exceed the variation due to the planets. The
main technique used here is a self-consistent version of the high-pass filter
used by Queloz et al. (2009) in the first mass determination of CoRoT-7b and
CoRoT-7c. The results are compared to those given by two alternative
techniques: (1) The approach proposed by Hatzes et al. (2010) using only those
nights in which 2 or 3 observations were done; (2) A pure Fourier analysis. In
all cases, the eccentricities are taken equal to zero as indicated by the study
of the tidal evolution of the system; the periods are also kept fixed at the
values given by Queloz et al. Only the observations done in the time interval
BJD 2,454,847 - 873 are used because they include many nights with multiple
observations; otherwise it is not possible to separate the effects of the
rotation fourth harmonic (5.91d = Prot/4) from the alias of the orbital period
of CoRoT-7b (0.853585 d). The results of the various approaches are combined to
give for the planet masses the values 8.0 \pm 1.2 MEarth for CoRoT-7b and 13.6
\pm 1.4 MEarth for CoRoT 7c. An estimation of the variation of the radial
velocity of the star due to its activity is also given.The results obtained
with 3 different approaches agree to give masses larger than those in previous
determinations. From the existing internal structure models they indicate that
CoRoT-7b is a much denser super-Earth. The bulk density is 11 \pm 3.5 g.cm-3 .
CoRoT-7b may be rocky with a large iron core.Comment: 12 pages, 11 figure
Transit Timing Observations from Kepler: VI. Potentially interesting candidate systems from Fourier-based statistical tests
We analyze the deviations of transit times from a linear ephemeris for the
Kepler Objects of Interest (KOI) through Quarter six (Q6) of science data. We
conduct two statistical tests for all KOIs and a related statistical test for
all pairs of KOIs in multi-transiting systems. These tests identify several
systems which show potentially interesting transit timing variations (TTVs).
Strong TTV systems have been valuable for the confirmation of planets and their
mass measurements. Many of the systems identified in this study should prove
fruitful for detailed TTV studies.Comment: 32 pages, 6 of text and one long table, Accepted to Ap
Possible Disintegrating Short-Period Super-Mercury Orbiting KIC 12557548
We report here on the discovery of stellar occultations, observed with
Kepler, that recur periodically at 15.685 hour intervals, but which vary in
depth from a maximum of 1.3% to a minimum that can be less than 0.2%. The star
that is apparently being occulted is KIC 12557548, a K dwarf with T_eff = 4400
K and V = 16. Because the eclipse depths are highly variable, they cannot be
due solely to transits of a single planet with a fixed size. We discuss but
dismiss a scenario involving a binary giant planet whose mutual orbit plane
precesses, bringing one of the planets into and out of a grazing transit. We
also briefly consider an eclipsing binary, that either orbits KIC 12557548 in a
hierarchical triple configuration or is nearby on the sky, but we find such a
scenario inadequate to reproduce the observations. We come down in favor of an
explanation that involves macroscopic particles escaping the atmosphere of a
slowly disintegrating planet not much larger than Mercury. The particles could
take the form of micron-sized pyroxene or aluminum oxide dust grains. The
planetary surface is hot enough to sublimate and create a high-Z atmosphere;
this atmosphere may be loaded with dust via cloud condensation or explosive
volcanism. Atmospheric gas escapes the planet via a Parker-type thermal wind,
dragging dust grains with it. We infer a mass loss rate from the observations
of order 1 M_E/Gyr, with a dust-to-gas ratio possibly of order unity. For our
fiducial 0.1 M_E planet, the evaporation timescale may be ~0.2 Gyr. Smaller
mass planets are disfavored because they evaporate still more quickly, as are
larger mass planets because they have surface gravities too strong to sustain
outflows with the requisite mass-loss rates. The occultation profile evinces an
ingress-egress asymmetry that could reflect a comet-like dust tail trailing the
planet; we present simulations of such a tail.Comment: 14 pages, 7 figures; submitted to ApJ, January 10, 2012; accepted
March 21, 201
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