3,287 research outputs found

    Immunoanalytical Approach for Detecting and Identifying Ancestral Peptide Biomarkers in Early Earth Analogue Environments

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    Several mass spectrometry and spectroscopic techniques have been used in the search for molecular biomarkers on Mars. A major constraint is their capability to detect and identify large and complex compounds such as peptides or other biopolymers. Multiplex immunoassays can detect these com-pounds, but antibodies must be produced for a large number of sequence-dependent molecular targets. Ancestral Sequence Re-construction (ASR) followed by protein "resurrection" in the lab can help to narrow the selection of targets. Herein, we propose an immunoanalytical method to identify ancient and universally conserved protein/peptide sequences as targets for identifying ancestral biomarkers in nature. We have developed, tested, and validated this approach by producing antibodies to eight previously described ancestral resurrected proteins (three beta-lactamases, three thioredoxins, one Elongation Factor Tu, and one RuBisCO, all of them theoretically dated as Precambrian), and used them as a proxy to search for any potential feature of them that could be present in current natural environments. By fluorescent sandwich microarray immunoassays (FSMI), we have detected positive immunoreactions with antibodies to the oldest beta-lactamase and thioredoxin proteins (ca. 4 Ga) in samples from a hydrothermal environment. Fine epitope mapping and inhibitory immunoassays allowed the identification of well-conserved epitope peptide sequences that resulted from ASR and were present in the sample. We corroborated these results by metagenomic sequencing and found several genes encoding analogue proteins with significant matches to the peptide epitopes identified with the antibodies. The results demonstrated that peptides inferred from ASR studies have true counterpart analogues in Nature, which validates and strengthens the well-known ASR/protein resurrection technique and our immunoanalytical approach for investigating ancient environments and metabolisms on Earth and elsewhere

    Adaptive Optics Imaging of IRAS 18276-1431: a bipolar pre-planetary nebula with circumstellar "searchlight beams" and "arcs"

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    We present high-angular resolution images of the post-AGB nebula IRAS18276-1431 (also known as OH17.7-2.0) obtained with the Keck II Adaptive Optics (AO) system in its Natural Guide Star (NGS) mode in the Kp, Lp, and Ms near-infrared bands. We also present supporting optical F606W and F814W HST images as well as interferometric observations of the 12CO(J=1-0), 13CO(J=1-0), and 2.6mm continuum emission with OVRO. The envelope of IRAS18276-1431 displays a clear bipolar morphology in our optical and NIR images with two lobes separated by a dark waist and surrounded by a faint 4.5"x3.4" halo. Our Kp-band image reveals two pairs of radial ``searchlight beams'' emerging from the nebula center and several intersecting, arc-like features. From our CO data we derive a mass of M>0.38[D/3kpc]^2 Msun and an expansion velocity v_exp=17km/s for the molecular envelope. The density in the halo follows a radial power-law proportional to r^-3, which is consistent with a mass-loss rate increasing with time. Analysis of the NIR colors indicates the presence of a compact central source of ~300-500K dust illuminating the nebula in addition to the central star. Modeling of the thermal IR suggests a two-shell structure in the dust envelope: 1) an outer shell with inner and outer radius R_in~1.6E16cm and R_out>~1.25E17cm, dust temperature T_d~105-50K, and a mean mass-loss rate of Mdot~1E-3Msun/yr; and 2) an inner shell with R_in~6.3E14cm, T_dust~500-105K, and Mdot~3E-5Msun/yr. An additional population of big dust grains (radius a>~0.4mm) with T_dust=150-20K and mass M_dust=(0.16-1.6)E-3 [D/3kpc]^2 Msun can account for the observed sub-mm and mm flux excess. The mass of the envelope enclosed within R_out=1.25E17cm derived from SED modeling is ~1[D/3kpc]^2 Msun.Comment: 46 pages, 14 figures, 3 tables, accepted for publication in ApJ. Figures 12 & 13 in low resolution. Full resolution versions are available upon request to the first autho

    Maria Zambrano amongst the philosophers: an introduction

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    This is the opening article to the monographic issue, introducing the Spanish philosopher Maria Zambrano to an Anglophone audience not familiar with her work. It covers biographical information as well as references to the main philosophical areas explored and work published by the author. In addition, it introduces the articles included in the issue and the rationale behind this special issue: to locate Zambrano’s philosophical thought alongside that of other more widely recognised thinkers in the Western world. Indeed, the articles included explore the links between Zambrano’s thought and a wide range of themes and ideas associated with other European thinkers including, Critical Theory and the Frankfurt School, Husserl and Jan Patočka’s reflections on Europe, a psychoanalytical reading of the experience of exile, a reading of the metaphor of light in the works of Zambrano through the works of Jacques Derrida y Hans Blumenberg, and present day debates around the crisis and reconstruction of the subject. Finally, the article introduces the anthology of texts by Zambrano in English translation included in the monographic issue

    The influence of defined ante-mortem stressors on the early post-mortem biochemical processes in the abdominal muscle of the Norway lobster, Nephrops norvegicus (Linnaeus, 1758)

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    The effects of four different ante-mortem stressors (exercise, emersion, starvation and a patent infection with the parasite Hematodinium sp.) on post-mortem processes have been investigated in the abdominal muscle of Norway lobster Nephrops norvegicus by measuring changes in the pH, the levels of glycogen, l-lactate, arginine phosphate, ATP, ADP, AMP, IMP, HxR, Hx and the adenylate energy charge (AEC) over a time course of 24 h with samples being taken at 0, 3, 6, 12 and 24 h. The acute stresses of intense exercise and 2 h emersion resulted in a premature onset of anaerobic glycolysis, leading both to an enhanced glycogen depletion rate and an early accumulation of l-lactate. The chronic stressors, starvation and parasite infection, resulted in a complete ante-mortem depletion of muscle glycogen and consequently the failure of post-mortem glycolytic fermentation. Post-mortem pH and ATP inter-conversion were significantly altered in chronically stressed animals. Ante-mortem, a rapid, almost complete depletion of arginine phosphate was observed in all stress groups. The AEC was altered significantly by all stresses, indicating a strong energy demand. The findings suggest that ante-mortem stressors strongly influence the post-mortem biochemical processes. The laboratory-based results are compared to 'field' data and effects on post-harvest product quality are discussed

    Stellar Population gradients in galaxy discs from the CALIFA survey

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    While studies of gas-phase metallicity gradients in disc galaxies are common, very little has been done in the acquisition of stellar abundance gradients in the same regions. We present here a comparative study of the stellar metallicity and age distributions in a sample of 62 nearly face-on, spiral galaxies with and without bars, using data from the CALIFA survey. We measure the slopes of the gradients and study their relation with other properties of the galaxies. We find that the mean stellar age and metallicity gradients in the disc are shallow and negative. Furthermore, when normalized to the effective radius of the disc, the slope of the stellar population gradients does not correlate with the mass or with the morphological type of the galaxies. Contrary to this, the values of both age and metallicity at \sim2.5 scale-lengths correlate with the central velocity dispersion in a similar manner to the central values of the bulges, although bulges show, on average, older ages and higher metallicities than the discs. One of the goals of the present paper is to test the theoretical prediction that non-linear coupling between the bar and the spiral arms is an efficient mechanism for producing radial migrations across significant distances within discs. The process of radial migration should flatten the stellar metallicity gradient with time and, therefore, we would expect flatter stellar metallicity gradients in barred galaxies. However, we do not find any difference in the metallicity or age gradients in galaxies with without bars. We discuss possible scenarios that can lead to this absence of difference.Comment: 24 pages, 17 figures, accepted for publication in A&

    In vitro Evaluation of Phthalimide Derivatives Against Cancer Cell lines

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    Los cánceres de pulmón, próstata e hígado se encuentran entre los más prevalentes en los hombres. El cáncer de mama, de cuello uterino y de tiroides se encuentran entre los más prevalentes en mujeres (OMS, 2019). El tratamiento del cáncer generalmente incluye quimioterapia y radioterapia; sin embargo, los medicamentos contra el cáncer disponibles tienen una selectividad baja y causan efectos adversos graves, como nefrotoxicidad, neurotoxicidad y mielosupresión (Matsuo et al., 2010). Por tanto, el diseño y desarrollo de compuestos como nuevos agentes anticancerígenos frente a los tipos de cáncer de mayor incidencia son de vital importancia en el campo de la salud. Los derivados de ftalimida son compuestos prometedores para el desarrollo de nuevos agentes anticancerígenos (Li et al., 2011; Grigalius y Petrikaite, 2017; Kamal et al., 2002). Basado en lo anterior, Este trabajo tuvo como objetivo evaluar la actividad antiproliferativa de 43 derivados de ftalimida contra una línea celular de cáncer principal en hombres (HepG2) y dos líneas celulares de cáncer principales en mujeres (HeLa y 4T1). Además, se determinó la citotoxicidad de los compuestos contra una línea celular de fibroblasto murino normal (3T3). Los resultados mostraron que los compuestos C16, E11 y E16 presentaron la mejor actividad antiproliferativa contra las líneas celulares HeLa y 4T1. El compuesto H16 solo disminuyó la proliferación celular en un 32% contra la línea celular HepG2. Los compuestos H5, H16, E2, E16 y C1 no afectaron a la proliferación de la línea celular 3T3. Demostrando que sería importante continuar con el análisis de este tipo de compuestos frente a diferentes cánceres para encontrar nuevos compuestos con mejor actividad que los actualmente disponibles en el mercado

    Echelle long-slit optical spectroscopy of evolved stars

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    We present echelle long-slit optical spectra of a sample of objects evolving off the AGB, most of them in the pre-planetary nebula (pPN) phase, obtained with the ESI and MIKE spectrographs at Keck-II and Magellan-I, respectively. The total wavelength range covered with ESI (MIKE) is ~3900 to 10900 A (~3600 to 7200A). In this paper, we focus our analysis mainly on the Halpha profiles. Prominent Halpha emission is detected in half of the objects, most of which show broad Halpha wings (up to ~4000 km/s). In the majority of the Halpha-emission sources, fast, post-AGB winds are revealed by P-Cygni profiles. In ~37% of the objects Halpha is observed in absorption. In almost all cases, the absorption profile is partially filled with emission, leading to complex, structured profiles that are interpreted as an indication of incipient post-AGB mass-loss. All sources in which Halpha is seen mainly in absorption have F-G type central stars, whereas sources with intense Halpha emission span a larger range of spectral types from O to G. Shocks may be an important excitation agent of the close stellar surroundings for objects with late type central stars. Sources with pure emission or P Cygni Halpha profiles have larger J-K color excess than objects with Halpha mainly in absorption, which suggests the presence of warm dust near the star in the former. The two classes of profile sources also segregate in the IRAS color-color diagram in a way that intense Halpha-emitters have dust grains with a larger range of temperatures. (abridged)Comment: 68 pages, 14 figures, accepted for publication in ApJS (abstract abridged

    Prospective study of urinary tract infection surveillance after kidney transplantation

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    <p>Abstract</p> <p>Background</p> <p>Urinary tract infection (UTI) remains one of the main complications after kidney transplantation and it has serious consequences.</p> <p>Methods</p> <p>Fifty-two patients with kidney transplantation were evaluated for UTI at 3-145 days (mean 40.0 days) after surgery.. Forty-two received a graft from a live donor and 10 from a deceased donor. There were 22 female and 30 male patients, aged 11-47 years. Microscopic examinations, leukocyte esterase stick, and urinary culture were performed every third day and weekly after hospitalization. A positive culture was consider when patients presented bacterial counts up to 10<sup>5</sup> counts.</p> <p>Results</p> <p>UTI developed in 19/52 (37%) patients at 3-75 days (mean 19.5 days after transplantation. Recurrent infection was observed in 7/52 (13.4%) patients at days 17-65. UTI was more frequent in patients who received deceased grafts compared with live grafts (7/10, 70% <it>vs</it>. 12/42, 28%; p < 0.007). Female patients were more susceptible than male (11/22, 50% <it>vs</it>. 8/22, 36.35%; p < 0.042). Five-year survival rate was 94.5% (49/52 patients). Kidney Graft exit update is 47/52 (90.2%), and there were no significant differences between graft rejection and UTI (p = 0.2518). Isolated bacteria were <it>Escherichia coli </it>(31.5%), <it>Candida albicans </it>(21.0%) and <it>Enterococcus </it>spp. (10.5%), followed by <it>Pseudomonas aeruginosa, Klebsiella pneumoniae, Morganella </it><it>morganii, Enterobacter cloacae </it>and <it>Micrococcus </it>spp. Secondary infections were produced by (7/19, 36.8%). <it>Enterococcus </it>spp. (57%), <it>E. coli </it>(28%) and <it>Micrococcus </it>spp. (14.2%). Antibiotic resistance was 22% for ciprofloxacin and 33% for ampicillin. Therapeutic alternatives were aztreonam, trimethoprim-sulfamethoxazole, netilmicin and fosfomycin.</p> <p>Conclusions</p> <p>Surveillance of UTI for the first 3 months is a good option for improving quality of life of kidney transplantation patients and the exit of graft function especially for female patients and those receiving deceased grafts. Antibiograms provided a good therapeutic alternative to patients who presented with UTIs after receiving a kidney allograft.</p

    CALIFA, the Calar Alto Legacy Integral Field Area survey: I. Survey presentation

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    We present here the Calar Alto Legacy Integral Field Area (CALIFA) survey, which has been designed to provide a first step in this direction.We summarize the survey goals and design, including sample selection and observational strategy.We also showcase the data taken during the first observing runs (June/July 2010) and outline the reduction pipeline, quality control schemes and general characteristics of the reduced data. This survey is obtaining spatially resolved spectroscopic information of a diameter selected sample of 600\sim600 galaxies in the Local Universe (0.005< z <0.03). CALIFA has been designed to allow the building of two-dimensional maps of the following quantities: (a) stellar populations: ages and metallicities; (b) ionized gas: distribution, excitation mechanism and chemical abundances; and (c) kinematic properties: both from stellar and ionized gas components. CALIFA uses the PPAK Integral Field Unit (IFU), with a hexagonal field-of-view of \sim1.3\sq\arcmin', with a 100% covering factor by adopting a three-pointing dithering scheme. The optical wavelength range is covered from 3700 to 7000 {\AA}, using two overlapping setups (V500 and V1200), with different resolutions: R\sim850 and R\sim1650, respectively. CALIFA is a legacy survey, intended for the community. The reduced data will be released, once the quality has been guaranteed. The analyzed data fulfill the expectations of the original observing proposal, on the basis of a set of quality checks and exploratory analysis. We conclude from this first look at the data that CALIFA will be an important resource for archaeological studies of galaxies in the Local Universe.Comment: 32 pages, 29 figures, Accepted for publishing in Astronomy and Astrophysic
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