325 research outputs found

    From pre- to young Planetary Nebulae: radio continuum variability

    Full text link
    Searching for variability, we have observed a sample of hot post-AGB stars and young Planetary Nebulae candidates with the Very Large Array at 4.8, 8.4, and 22.4 GHz. The sources had been previously detected in the radio continuum, which is a proof that the central stars have started ionising their circumstellar envelopes and an increase in radio flux with time can be expected as a result of the progression of the ionisation front. Such a behaviour has been found in IRAS 18062+2410, whose radio modelling has allowed us to determine that its ionised mass has increased from 10^{-4} to 3.3 10^{-4} M_sun in 8 years and its envelope has become optically thin at lower frequencies. Different temporal behaviours have been found for three other sources. IRAS 17423-1755 has shown a possibly periodic pattern and an inversion of its radio spectral index, as expected from a varying stellar wind. We estimate that the radio flux arises from a very compact region around the central star (10^{15} cm) with an electron density of 2 10^6 cm^{-3}. IRAS 22568+6141 and 17516-2525 have decreased their radio flux densities of about 10% per year over 4 years. While a linear increase of the flux density with time points out to the progression of the ionisation front in the envelope, decreases as well as quasi-periodic patterns may indicate the presence of unstable stellar winds/jets or thick dusty envelopes absorbing ionising photons.Comment: 9 pages, 5 figures, accepted for publication on MNRA

    Nuclear Receptors in Nonalcoholic Fatty Liver Disease

    Get PDF
    Nuclear receptors comprise a superfamily of ligand-activated transcription factors that are involved in important aspects of hepatic physiology and pathophysiology. There are about 48 nuclear receptors in the human. These nuclear receptors are regulators of many hepatic processes including hepatic lipid and glucose metabolism, bile acid homeostasis, drug detoxification, inflammation, regeneration, fibrosis, and tumor formation. Some of these receptors are sensitive to the levels of molecules that control lipid metabolism including fatty acids, oxysterols, and lipophilic molecules. These receptors direct such molecules to the transcriptional networks and may play roles in the pathogenesis and treatment of nonalcoholic fatty liver disease. Understanding the mechanisms underlying the involvement of nuclear receptors in the pathogenesis of nonalcoholic fatty liver disease may offer targets for the development of new treatments for this liver disease

    hypersaline infusion protocol through the portal vein may focus electroporation on tumor tissue, but is it really safe? Ppreliminary results

    Get PDF
    Introduction: irreversible Electroporation (IRE) is highly dependent on the electrical conductivity of the tissue and the high conductivity of tumor tissue, which leads to a lower field than that in the surrounding healthy tissue. Hypersaline Infusion (HI) through the portal vein focuses IRE on scattered liver tumors, by creating a differential conductivity between the different types of tissue. The aim of this study is to determine the effects of the HI protocol on the hepatic and histological biochemical results. Methods: Ten male Sprague Dawley rats were used for HI protocol. Blood samples were collected at pre-, immediately post-, 24-hrs, 72-hrs, 1- week and 3-weeks post-HI. All the animals were sacrificed after a one-month follow-up in order to collect histological samples. Results: The mortality rate in this procedure reached 30% (3/10). Only the pH and transaminases at 24-hrs were significantly and directly linked to mortality (p=0.036 and p=0.004, respectively). The three non-surviving animals had a four-time higher AST level at 24-hrs. Natremianormalized at 24-hrs post-HI. Statistically significant differences were found in hepatic necrosis between the non-surviving (n=3) and surviving rats (n=7) (30.67 ± 10.97 vs. 2.86 ± 7.56% respectively, p=0.01). Discussion: HI through the portal system involves a significant risk of possibly lethal cytolysis and acidosis. Therefore, compensatory measures and a reduced saline overload are warranted to improve the survival rates

    Effect of protein extraction and fractionation of chia seeds grown in different locations: Nutritional, antinutritional and protein quality assessment

    Get PDF
    Chia (Salvia hispanica) has become increasingly popular in recent years due to its high protein content, among other nutritional benefits. This study aims to evaluate the nutritional and antinutritional composition, protein profile and protein quality of two chia seeds grown in Mexico and the UK, as well as to assess the impact that occurs during protein extraction and fractionation. Protein content of chia samples showed an increase after degumming, defatting, and extraction, obtaining protein concentrates from Mexican (MPC) and British (BPC) chia seeds with 88.32 and 89.20 g/100 g dw, respectively. Main protein fractions found in both chia seeds were globulins (Glo) and albumins (Alb). Essential amino acid index (EAAI) of chia samples ranged between 189.40 and 496.73% showing a 2-fold increase in comparison to the reference protein. In vitro protein digestibility (IVPD) increased after protein extraction (91% for MPC and BPC) but decreased after fractionation (∼68%). Trypsin inhibitors increased 78–82% after protein extraction, while total phenolics content (TPC) increased 7.77- and 5.76-fold for Mexican albumins (MAlb) and British albumins (BAlb), respectively. Phytic acid content showed a reduction of > 90% after extraction/fractionation. These findings showed that depending on the extraction and/or fractionation methods used the protein quality, digestibility and antinutrients will be highly influenced

    Análisis, diseño y construcción de un chasis autoportante de material composite

    Get PDF
    Esta ponencia presenta el análisis estructural de un chasis autoportante para un vehículo monoplaza de bajo consumo, realizada en materiales compuestos. Este estudio comprende el análisis de los modos propios de vibración y su incidencia en la rigidez del chasis y la carrocería del vehículo. Se parte de un modelo existente, se parametriza y simula. La validación de los resultados se realiza mediante los resultados se realiza mediante los datos obtenidos en las pruebas de laboratorio. Los posibles materiales para utilizar en el nuevo chasis propuesto se caracterizan mediante ensayos mecánicos estándar a fin de parametrizarlos para los programas de simulación. El ajuste fino de los valores obtenidos se realiza mediante las pruebas de laboratorio de la carrocería del modelo existente.Postprint (published version

    Time-dependent ejection velocity model for the outflow of Hen 3--1475

    Full text link
    We present 2D axisymmetric and 3D numerical simulations of the proto-planetary nebula Hen 3-1475, which is characterized by a remarkably highly collimated optical jet, formed by a string of shock-excited knots along the axis of the nebula. It has recently been suggested that the kinematical and morphological properties of the Hen 3-1475 jet could be the result of an ejection variability of the central source (Riera et al. 2003). The observations suggest a periodic variability of the ejection velocity superimposed on a smoothly increasing ejection velocity ramp. From our numerical simulations, we have obtained intensity maps (for different optical emission lines) and position-velocity diagrams, in order to make a direct comparison with the HST observations of this object. Our numerical study allows us to conclude that a model of a precessing jet with a time-dependent ejection velocity, which is propagating into an ISM previously perturbed by an AGB wind, can succesfully explain both the morphological and the kinematical characteristics of this proto-planetary nebula.Comment: Astronomy and Astrophysics (accepted) (8 figures

    Administration of royal jelly in estrus synchronization protocols for wool and hair sheep

    Get PDF
    Objetive: To know the most representative results of the use of royal jelly in reproductive protocols in wool and hair sheep,Desing/methodology/approach: A review of studies referenced in scientific databases published in the livestock sector was carried out. Results: In sheep, the administration of royal jelly in conjunction with reproductive management protocols improves the response to oestrus timing, oestrus onset time and duration, number of large follicles, ovulatory rate, and gestation rate. Study limitations/implications: Royal jelly is a substance that has beneficial effects on sheep reproductive variables, however the cost can be a limitation for its incorporation into the synchronization protocols, in addition to being necessary to elucidate the active metabolites that exert the action and the most effective route of administration.Findings/conclusions: Royal jelly can be an alternative to be incorporated in the estrous synchronization programs in sheep in order to replace some hormonal and without reducing reproductive variables.Objective: To assess the most relevant results on the usage of royal jelly in reproductive protocols of wool and hair sheep. Design/methodology/approach: A review of studies referenced and published in scientific databases regard the livestock sector. Results: In ewes, administration of “royal jelly” in addition to reproductive management protocols improves the response to estrus synchronization, time of onset and duration of estrus, number of large follicles, ovulatory rate and gestation rate. Study limitations/implications: Royal jelly is a substance with beneficial effects on reproductive variables in ewes; however, the cost may be a limitation for its incorporation in synchronization protocols. Additionally, it is necessary to clarify the active metabolites that exert the action and the most effective route of administration. Findings/conclusions: Royal jelly can be an alternative incorporated to estrus synchronization programs in ewes to substitute some hormones without decreasing reproductive variables

    Differential cytogenetic profile in advanced chronic myeloid leukemia with sequential lymphoblastic and myeloblastic blast crisis

    Get PDF
    Frequency of additional chromosomal abnormalities in chronic myeloid leukemia (CML) is estimated to be 7% in chronic phase and increases to 40–70% in advanced disease. Progression of CML from chronic phase to accelerated phase or blast crisis is often associated with secondary chromosomal aberrations. We report an exceptional case of CML as debut in lymphoblastic blast crisis and a subsequent progression in myeloblastic blast crisis with rare cytogenetic abnormalities

    Shock excitation of the knots of Hen 3-1475

    Get PDF
    We present new optical STIS HST spectroscopic observations of the jets of the proto-planetary nebula Hen 3-1475. The excitation conditions of the knots of Hen 3-1475 are derived from the observed optical spectra, confirming that the knots are shock excited. The shocked spectra are qualitatively reproduced by simple ``3/2''D bow shock models. We present a set of bow shock models devoted to planetary nebulae, and discuss the effects of the pre-ionization conditions, the bow shock velocity, the bow shock shape and the chemical abundances on the predicted spectra. To explore the reliability of the ``3/2''D bow shock models, we also compare the observed spectra of other three proto-planetary nebulae (M 1-92, M 2-56 and CRL 618) to the predicted spectra.Comment: 13 pages. A&A (in press
    corecore