193 research outputs found

    Evidence of bar-driven secular evolution in the gamma-ray narrow-line Seyfert 1 galaxy FBQS J164442.5+261913

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    We present near-infrared imaging of FBQS J164442.5+261913, one of the few gamma-ray emitting narrowline Seyfert 1 galaxies detected at high significance level by Fermi Large Area Telescope. This study is the first morphological analysis performed of this source and the third performed of this class of objects. Conducting a detailed 2D modelling of its surface brightness distribution and analysing its J - K-s colour gradients, we find that FBQS J164442.5+261913 is statistically most likely hosted by a barred lenticular galaxy (SB0). We find evidence that the bulge in the host galaxy of FBQS J164442.5+261913 is not classical but pseudo, against the paradigm of powerful relativistic jets exclusively launched by giant ellipticals. Our analysis also reveals the presence of a ring with diameter equalling the bar length (r(bar) = 8.13 +/- 0.25 kpc), whose origin might be a combination of bar- driven gas rearrangement and minor mergers, as revealed by the apparent merger remnant in the J-band image. In general, our results suggest that the prominent bar in the host galaxy of FBQS J164442.5+ 261913 has mostly contributed to its overall morphology driving a strong secular evolution, which plays a crucial role in the onset of the nuclear activity and the growth of the massive bulge. Minor mergers, in conjunction, are likely to provide the necessary fresh supply of gas to the central regions of the host galaxy

    Detection of helicoidal motion in the optical jet of PKS 0521-365

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    The jet activity of active galactic nuclei (AGNs), and its interaction with the interstellar medium, may play a pivotal role in the processes that regulate the growth and star formation of its host galaxy. Observational evidence that pinpoints the conditions of such interaction is paramount to unveil the physical processes involved. We report on the discovery of extended emission-line regions exhibiting an S-shaped morphology along the optical jet of the radioloud AGN PKS 0521-365 (z = 0.055), by using long-slit spectroscopic observations obtained with FOcal Reducer/low dispersion Spectrograph 2 on the Very Large Telescope. The velocity pattern derived from the [O II].3727 angstrom, H beta lambda 4861 angstrom and [O III] lambda lambda 4959, 5007 angstrom emission lines is well fitted by a sinusoidal function of the form: v(r) = alpha r(1/2)sin(beta r(1/2) + gamma), suggesting helicoidal motions along the jet up to distances of 20 kpc. We estimate a lower limit for the mass of the outflowing ionized gas along the jet of similar to 10(4)M(circle dot). Helical magnetic fields and jet precession have been proposed to explain helicoidal paths along the jet at pc scales; nevertheless, it is not clear yet whether these hypotheses may hold at kpc scales

    E X I T (ex-utero intrapartum therapy) en linfangioma cervical fetal

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    Se presenta un caso clínico de una embarazada primigesta de 17 años, con un feto con gran masa cervical a las 20 semanas, se diagnostica como linfangioma cervical. La evaluación prenatal concluye que existe gran riesgo de asfixia perinatal por obstrucción de la vía aérea superior, se resuelve el parto mediante procedimiento EXIT (ex-utero intrapartum therapy) a las 37 semanas. Se logra realizar intubación con larin-goscopia directa, con un tiempo de by-pass uteroplacentario de 7 minutos. Se obtiene un recién nacido de 3300 g, al segundo día se opera del tumor con buenos resultados. Se revisa el protocolo del procedimiento EXIT en sus aspectos anestésicos, obstétricos, quirúrgicos y neonatológicos. Se concluye que el EXIT debe ser planteado en todo caso en que se sospeche obstrucción de la vía aérea superior y puede ser realizado en hospitales que cuenten con equipamiento habitual y un equipo médico multidisciplinario

    Integrated Functions of Pax3 and Pax7 in the Regulation of Proliferation, Cell Size and Myogenic Differentiation

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    Pax3 and Pax7 are paired-box transcription factors with roles in developmental and adult regenerative myogenesis. Pax3 and Pax7 are expressed by postnatal satellite cells or their progeny but are down regulated during myogenic differentiation. We now show that constitutive expression of Pax3 or Pax7 in either satellite cells or C2C12 myoblasts results in an increased proliferative rate and decreased cell size. Conversely, expression of dominant-negative constructs leads to slowing of cell division, a dramatic increase in cell size and altered morphology. Similarly to the effects of Pax7, retroviral expression of Pax3 increases levels of Myf5 mRNA and MyoD protein, but does not result in sustained inhibition of myogenic differentiation. However, expression of Pax3 or Pax7 dominant-negative constructs inhibits expression of Myf5, MyoD and myogenin, and prevents differentiation from proceeding. In fibroblasts, expression of Pax3 or Pax7, or dominant-negative inhibition of these factors, reproduce the effects on cell size, morphology and proliferation seen in myoblasts. Our results show that in muscle progenitor cells, Pax3 and Pax7 function to maintain expression of myogenic regulatory factors, and promote population expansion, but are also required for myogenic differentiation to proceed

    ALMA-IMF IX: Catalog and Physical Properties of 315 SiO Outflow Candidates in 15 Massive Protoclusters

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    We present a catalog of 315 protostellar outflow candidates detected in SiO J=5-4 in the ALMA-IMF Large Program, observed with ~2000 au spatial resolution, 0.339 km/s velocity resolution, and 2-12 mJy/beam (0.18-0.8 K) sensitivity. We find median outflow masses, momenta, and kinetic energies of ~0.3 M_{\odot}, 4 M_{\odot} km/s, and 1045^{45} erg, respectively. Median outflow lifetimes are 6,000 years, yielding median mass, momentum, and energy rates of M˙\dot{M} = 104.4^{-4.4} M_{\odot} yr1^{-1}, P˙\dot{P} = 103.2^{-3.2} M_{\odot} km/s yr1^{-1}, and E˙\dot{E} = 1 L_{\odot}. We analyze these outflow properties in the aggregate in each field. We find correlations between field-aggregated SiO outflow properties and total mass in cores (~3-5σ\sigma), and no correlations above 3σ\sigma with clump mass, clump luminosity, or clump luminosity-to-mass ratio. We perform a linear regression analysis and find that the correlation between field-aggregated outflow mass and total clump mass - which has been previously described in the literature - may actually be mediated by the relationship between outflow mass and total mass in cores. We also find that the most massive SiO outflow in each field is typically responsible for only 15-30% of the total outflow mass (60% upper limit). Our data agree well with the established mechanical force-bolometric luminosity relationship in the literature, and our data extend this relationship up to L \geq 106^6 L_{\odot} and P˙\dot{P} \geq 1 M_{\odot} km/s yr1^{-1}. Our lack of correlation with clump L/M is inconsistent with models of protocluster formation in which all protostars start forming at the same time.Comment: 46 pages, 14 figures, 10 tables. This publication has an associated Zenodo entry, which can be found here: https://zenodo.org/records/835059

    Dlk1 Is Necessary for Proper Skeletal Muscle Development and Regeneration

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    Delta-like 1homolog (Dlk1) is an imprinted gene encoding a transmembrane protein whose increased expression has been associated with muscle hypertrophy in animal models. However, the mechanisms by which Dlk1 regulates skeletal muscle plasticity remain unknown. Here we combine conditional gene knockout and over-expression analyses to investigate the role of Dlk1 in mouse muscle development, regeneration and myogenic stem cells (satellite cells). Genetic ablation of Dlk1 in the myogenic lineage resulted in reduced body weight and skeletal muscle mass due to reductions in myofiber numbers and myosin heavy chain IIB gene expression. In addition, muscle-specific Dlk1 ablation led to postnatal growth retardation and impaired muscle regeneration, associated with augmented myogenic inhibitory signaling mediated by NF-κB and inflammatory cytokines. To examine the role of Dlk1 in satellite cells, we analyzed the proliferation, self-renewal and differentiation of satellite cells cultured on their native host myofibers. We showed that ablation of Dlk1 inhibits the expression of the myogenic regulatory transcription factor MyoD, and facilitated the self-renewal of activated satellite cells. Conversely, Dlk1 over-expression inhibited the proliferation and enhanced differentiation of cultured myoblasts. As Dlk1 is expressed at low levels in satellite cells but its expression rapidly increases upon myogenic differentiation in vitro and in regenerating muscles in vivo, our results suggest a model in which Dlk1 expressed by nascent or regenerating myofibers non-cell autonomously promotes the differentiation of their neighbor satellite cells and therefore leads to muscle hypertrophy

    SINTESIS MAGNETIT (Fe3O4) NANOPARTIKEL DENGAN NATRIUM DODESIL SULFAT

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    Telah dilakukan sintesis magnetit (Fe3O4) nanopartikel dengan Natrium Dodesil Sulfat (NaDS). Penelitian ini bertujuan untuk mengetahui pengaruh NaDS terhadap karakter kimia dan fisik magnetit nanopartikel hasil sintesis dengan metode kopresipitasi. Sintesis magnetit nanopartikel dilakukan dengan mereaksikan FeSO4.7H2O dan FeCl3.6H2O dengan perbandingan mol 1:2 serta natrium hidroksida (NaOH) sebagai presipitan dengan proses pengadukan pada suhu 60 °C selama 2 jam. Kajian pengaruh surfaktan pada sintesis magnetit nanopartikel dilakukan dengan variasi konsentrasi NaDS dari 1%, 3% dan 6% (b/v). Material hasil sintesis dikarakterisasi dengan spektrofotometer X-ray diffraction (XRD), Fourier Transform Infrared Spectrometer (FTIR), Scanning Electron Microscope-Energy Dispersive X-ray (SEM-EDX) dan Surface Area Analyzer (SAA). Hasil penelitian menunjukkan bahwa magnetit nanopartikel berhasil disintesis. Magnetit ditunjukkan oleh puncak difraksi utama pada 2θ 30,43o; 35,53o; 43,46o; 57,32o dan 62,84o. Ikatan Fe–O ditunjukkan dengan puncak serapan 565 cm-1 yang dianalisa lebih lanjut menggunakan EDX menunjukkan adanya unsur Fe dan O. Adanya surfaktan NaDS menaikkan ukuran partikel dan ukuran kristal magnetit dengan meningkatnya konsentrasi NaDS yang ditambahkan. Morfologi magnetit-NaDS semakin homogen berbentuk butiran-butiran kecil (grain) dengan ukuran partikel sekitar 30-100 nm. Ukuran kristal magnetit sebesar 11,07 nm (magnetit tanpa surfaktan); 13,62 nm (magnetit-NaDS 1%); 16,12 nm (magnetit-NaDS 3%) dan 11,17 nm (magnetit-NaDS 6%). Luas permukaan magnetit nanopartikel berturut-turut sebesar 89,67 m2/g (magnetit tanpa surfaktan); 102,50 m2/g (magnetit-NaDS 1%); 98,45 m2/g (magnetit-NaDS 3%) dan 82,92 m2/g (magnetit-NaDS 6%)

    Gene Transcription and Splicing of T-Type Channels Are Evolutionarily-Conserved Strategies for Regulating Channel Expression and Gating

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    T-type calcium channels operate within tightly regulated biophysical constraints for supporting rhythmic firing in the brain, heart and secretory organs of invertebrates and vertebrates. The snail T-type gene, LCav3 from Lymnaea stagnalis, possesses alternative, tandem donor splice sites enabling a choice of a large exon 8b (201 aa) or a short exon 25c (9 aa) in cytoplasmic linkers, similar to mammalian homologs. Inclusion of optional 25c exons in the III–IV linker of T-type channels speeds up kinetics and causes hyperpolarizing shifts in both activation and steady-state inactivation of macroscopic currents. The abundant variant lacking exon 25c is the workhorse of embryonic Cav3 channels, whose high density and right-shifted activation and availability curves are expected to increase pace-making and allow the channels to contribute more significantly to cellular excitation in prenatal tissue. Presence of brain-enriched, optional exon 8b conserved with mammalian Cav3.1 and encompassing the proximal half of the I–II linker, imparts a ∼50% reduction in total and surface-expressed LCav3 channel protein, which accounts for reduced whole-cell calcium currents of +8b variants in HEK cells. Evolutionarily conserved optional exons in cytoplasmic linkers of Cav3 channels regulate expression (exon 8b) and a battery of biophysical properties (exon 25c) for tuning specialized firing patterns in different tissues and throughout development
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