147 research outputs found

    Human Liver Stem Cell-Derived Extracellular Vesicles Target Hepatic Stellate Cells and Attenuate Their Pro-fibrotic Phenotype

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    Liver fibrosis occurs in response to chronic liver injury and is characterized by an excessive deposition of extracellular matrix. Activated hepatic stellate cells are primarily responsible for this process. A possible strategy to counteract the development of hepatic fibrosis could be the reversion of the activated phenotype of hepatic stellate cells. Extracellular vesicles (EVs) are nanosized membrane vesicles involved in intercellular communication. Our previous studies have demonstrated that EVs derived from human liver stem cells (HLSCs), a multipotent population of adult stem cells of the liver with mesenchymal-like phenotype, exert in vivo anti-fibrotic activity in the liver. However, the mechanism of action of these EVs remains to be determined. We set up an in vitro model of hepatic fibrosis using a human hepatic stellate cell line (LX-2) activated by transforming growth factor-beta 1 (TGF-β1). Then, we investigated the effect of EVs obtained from HLSCs and from human bone marrow-derived mesenchymal stromal cells (MSCs) on activated LX-2. The incubation of activated LX-2 with HLSC-EVs reduced the expression level of alpha-smooth muscle actin (α-SMA). Conversely, MSC-derived EVs induced an increase in the expression of pro-fibrotic markers in activated LX-2. The analysis of the RNA cargo of HLSC-EVs revealed the presence of several miRNAs involved in the regulation of fibrosis and inflammation. Predictive target analysis indicated that several microRNAs (miRNAs) contained into HLSC-EVs could possibly target pro-fibrotic transcripts. In particular, we demonstrated that HLSC-EVs shuttled miR-146a-5p and that treatment with HLSC-EVs increased miR-146a-5p expression in LX-2. In conclusion, this study demonstrates that HLSC-EVs can attenuate the activated phenotype of hepatic stellate cells and that their biological effect may be mediated by the delivery of anti-fibrotic miRNAs, such as miR-146a-5p

    Fístula Gastro-Esplénica por Linfoma: reporte de caso y revisión integrativa de la literatura

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    La fístula gastro-esplénica es una condición rara y potencialmente fatal causada, principalmente, por neoplasias.  Objetivos: Reportar un caso de fístula gastro-esplénica y realizar una revisión integrativa de la literatura. Caso clínico: Paciente mujer de 63 años, con cuadro de hiporexia, astenia, melena y masa abdominal de dos meses de evolución; internada por hematemesis masiva. Ante la imposibilidad de tratamiento endoscópico, se realizó una laparotomía exploradora de emergencia, donde se identificó un gran tumor esplénico que invadía la curvatura mayor gástrica. El abordaje quirúrgico incluyó gastrectomía segmentar con esplenectomía y cirugía de control de daños. El diagnóstico anatomo-patológico fue compatible con linfoma linfocítico de células pequeñas esplénico, fistulizado al estómago.  Discusión: La fístula gastro-esplénica es una entidad rara cuya principal causa son los tumores malignos, principalmente los linfomas de células grandes. La tomografía de abdomen es el examen de elección para el diagnóstico. El tratamiento definitivo, en la mayoría de los casos, consiste en la gastrectomía parcial, con o sin esplenectomía

    Iron and Nickel spectral opacity calculations in conditions relevant for pulsating stellar envelopes and experiments

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    Seismology of stars is strongly developing. To address this question we have formed an international collaboration OPAC to perform specific experimental measurements, compare opacity calculations and improve the opacity calculations in the stellar codes [1]. We consider the following opacity codes: SCO, CASSANDRA, STA, OPAS, LEDCOP, OP, SCO-RCG. Their comparison has shown large differences for Fe and Ni in equivalent conditions of envelopes of type II supernova precursors, temperatures between 15 and 40 eV and densities of a few mg/cm3 [2, 3, 4]. LEDCOP, OPAS, SCO-RCG structure codes and STA give similar results and differ from OP ones for the lower temperatures and for spectral interval values [3]. In this work we discuss the role of Configuration Interaction (CI) and the influence of the number of used configurations. We present and include in the opacity code comparisons new HULLAC-v9 calculations [5, 6] that include full CI. To illustrate the importance of this effect we compare different CI approximations (modes) available in HULLAC-v9 [7]. These results are compared to previous predictions and to experimental data. Differences with OP results are discussed.Comment: 4 pages, 3 figures, conference Inertial Fusion Sciences and Applications, Bordeaux, 12th to 16th September 2011; EPJ web of Conferences 201

    A novel radio imaging method for physical spectral index modelling

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    We present a new method, called "forced-spectrum fitting", for physically-based spectral modelling of radio sources during deconvolution. This improves upon current common deconvolution fitting methods, which often produce inaccurate spectra. Our method uses any pre-existing spectral index map to assign spectral indices to each model component cleaned during the multi-frequency deconvolution of WSClean, where the pre-determined spectrum is fitted. The component magnitude is evaluated by performing a modified weighted linear least-squares fit. We test this method on a simulated LOFAR-HBA observation of the 3C196 QSO and a real LOFAR-HBA observation of the 4C+55.16 FRI galaxy. We compare the results from the forced-spectrum fitting with traditional joined-channel deconvolution using polynomial fitting. Because no prior spectral information was available for 4C+55.16, we demonstrate a method for extracting spectral indices in the observed frequency band using "clustering". The models generated by the forced-spectrum fitting are used to improve the calibration of the datasets. The final residuals are comparable to existing multi-frequency deconvolution methods, but the output model agrees with the provided spectral index map, embedding correct spectral information. While forced-spectrum fitting does not solve the determination of the spectral information itself, it enables the construction of accurate multi-frequency models that can be used for wide-band calibration and subtraction.Comment: 17 pages, 9 figures, 5 tables. Accepted for publication in MNRA

    Assessing the impact of two independent direction-dependent calibration algorithms on the LOFAR 21-cm signal power spectrum

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    Detecting the 21-cm signal from the Epoch of Reionisation (EoR) is challenging due to the strong astrophysical foregrounds, ionospheric effects, radio frequency interference and instrumental effects. Understanding and calibrating these effects are crucial for the detection. In this work, we introduce a newly developed direction-dependent (DD) calibration algorithm DDECAL and compare its performance with an existing algorithm, SAGECAL, in the context of the LOFAR-EoR 21-cm power spectrum experiment. In our data set, the North Celestial Pole (NCP) and its flanking fields were observed simultaneously. We analyse the NCP and one of its flanking fields. The NCP field is calibrated by the standard pipeline, using SAGECAL with an extensive sky model and 122 directions, and the flanking field is calibrated by DDECAL and SAGECAL with a simpler sky model and 22 directions. Additionally, two strategies are used for subtracting Cassiopeia A and Cygnus A. The results show that DDECAL performs better at subtracting sources in the primary beam region due to the application of a beam model, while SAGECAL performs better at subtracting Cassiopeia A and Cygnus A. This indicates that including a beam model during DD calibration significantly improves the performance. The benefit is obvious in the primary beam region. We also compare the 21-cm power spectra on two different fields. The results show that the flanking field produces better upper limits compared to the NCP in this particular observation. Despite the minor differences between DDECAL and SAGECAL due to the beam application, we find that the two algorithms yield comparable 21-cm power spectra on the LOFAR-EoR data after foreground removal. Hence, the current LOFAR-EoR 21-cm power spectrum limits are not likely to depend on the DD calibration method.Comment: 28 pages, 14 figures, accepted for publication in A&

    Theory of laser ion acceleration from a foil target of nanometers

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    A theory for laser ion acceleration is presented to evaluate the maximum ion energy in the interaction of ultrahigh contrast (UHC) intense laser with a nanometer-scale foil. In this regime the energy of ions may be directly related to the laser intensity and subsequent electron dynamics. This leads to a simple analytical expression for the ion energy gain under the laser irradiation of thin targets. Significantly, higher energies for thin targets than for thicker targets are predicted. Theory is concretized to the details of recent experiments which may find its way to compare with these results.Comment: 22 pages 7 figures. will be submitted to NJ

    Prevalência de dermatoses em pacientes diabéticos

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    Objetivo: Avaliar a prevalência de dermatoses em pacientes diabéticos atendidos pelos serviços ambulatoriais de dermatologia e endocrinologia em um ambulatório do estado de Minas Gerais Métodos: Trata-se de um estudo transversal, baseado em arquivos de prontuários eletrônicos. A amostra foi de pacientes atendidos pelas especialidades de dermatologia e endocrinologia entre março e julho de 2021. Resultados: Os resultados se mostraram coerentes com as informações presentes na literatura, uma vez que as dermatoses foram mais prevalentes entre os pacientes diabéticos do sexo feminino e naqueles com mais de 60 anos. As condições mais frequentes, em ambos os sexos, masculino e feminino, foram respectivamente: Acantose Nigricans (18 casos), hiperceratose plantar (14 casos), Onicomicose (15 casos) e xerose cutânea (20 casos) Conclusão: Conclui-se que acantose nigricans, hiperceratose plantar, onicomicose e xerose cutânea foram as manifestações cutâneas mais prevalentes nos pacientes diabéticos desse ambulatório, o que torna imprescindível que seja dada maior ênfase dessas condições durante as consultas ambulatoriais

    Composite Wood–Concrete Structural Floor System with Horizontal Connectors

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    The concept of horizontal shear connection utilization on wood–concrete beams intends to be an alternative connection detail for composite wood–concrete decks. The volume of sawn-wood is over three times more expensive than concrete, in Brazil. In order to be competitive in the Brazilian market we need a composite deck with the least amount of wood and a simple and inexpensive connection detail. This research project uses medium to high density tropical hardwoods managed from the Brazilian Amazon region and construction steel rods. The beams studied are composed of a bottom layer of staggered wood boards and a top layer of concrete. The wood members are laterally nailed together to form a wide beam, and horizontal rebar connectors are installed before the concrete layer is applied on top. Two sets of wood–concrete layered beams with horizontal rebar connectors (6 and 8) were tested in third-point loading flexural bending. The initial results reveal medium composite efficiency for the beams tested. An improvement on the previously conceived connection detail (set with six connectors) for the composite wood–concrete structural floor system was achieved by the set with eight connectors. The new layout of the horizontal rebar connectors added higher composite efficiency for the beams tested. Further analysis with advanced rigorous numerical Finite Element Modeling is suggested to optimize the connection parameters. Composite wood–concrete decks can attend a large demand for pedestrian bridges, as well as residential and commercial slabs in the Brazilian Amazon. © 2014, The Author(s)
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