110 research outputs found

    Pure cervical radiculopathy due to spontaneous spinal epidural haematoma (SSEH): report of a case solved conservatively

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    Introduction: Spontaneous spinal epidural haematoma (SSEH) is widely recognised throughout the literature as a cause of myelopathy, radicular compression being very rarely reported. Surgical management is almost always recommended, especially in the cases of spinal cord compression. Conservative treatment is reported as a curiosity and only in the case of spontaneous improvement. This report presents the particular case of a 64-year-old patient undergoing anticoagulant therapy that had a cervical radiculopathy due to a SSEH confirmed by MRI. The patient improved spontaneously and symptoms were solved with unconventional conservative treatment and without stopping the anticoagulant therapy. Conclusions: Spontaneous epidural haematoma must be kept in mind when patients undergoing anticoagulant therapy have a sudden onset of cervicobrachialgia. Even though most spinal surgeons advocate surgical treatment, a conservative approach may lead to a complete recovery and may be considered as a good option in the case of radicular involvement. Discontinuation of the anticoagulant therapy may not always be needed, especially when the clinical syndrome improves spontaneously

    Diseño de una Planta Piloto de Refinación Electrolítica de un Bullion de Oro y Plata

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    Fil: García, Juan Antonio. Universidad Nacional de San Juan. Instituto de Investigaciones Mineras; Argentina (San Juan)Fil: Parra, Ricardo. Servicio Geológico Minero Argentino. Centro SEGEMAR Salta; Argentina.Fil: Montenegro, Carlos Alberto. Universidad Nacional de San Juan. Instituto de Investigaciones Mineras; Argentina (San Juan)Fil: Gómez Agustín Alberto. Universidad Nacional de San Juan. Instituto de Investigaciones Mineras; Argentina (San Juan)Fil: Núñez, Enrique Antonio. Universidad Nacional de San Juan. Instituto de Investigaciones Mineras; Argentina (San Juan)Fil: De la Iglesia, Daniel. Universidad Nacional de San Juan. Instituto de Investigaciones Mineras; Argentina (San juan)Fil: Matar, José Agustín. Universidad Nacional de San Juan. Instituto de Investigaciones Mineras; Argentina (San Juan)Fil: Villas Boas, Roberto. Centro de Tecnología Mineral CETEM; Brasil (Río de Janeiro)El presente trabajo de investigación fue realizado en el Instituto de Investigaciones Mineras (UNSJ) por los autores. Tuvo como objetivo el diseño, construcción y puesta en marcha de una planta refinadora de oro y plata a partir de un bullion impuro obtenido en la Mina Farallón Negro, provincia de Catamarca. Con los resultados obtenidos en esta etapa, se diseñó y construyó la planta comercial de refinación de oro y plata de la empresa Yacimientos Mineros Aguas de Dionisio (YMAD) en la ciudad de Catamarca. Este trabajo se presentó oportunamente en las Jornadas de Metalurgia extractiva realizadas en La Serena, Chile (CONAMET-SAM 2004

    Ionize Hard: Interstellar PO+ Detection

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    We report the first detection of the phosphorus monoxide ion (PO+) in the interstellar medium. Our unbiased and very sensitive spectral survey toward the G+0.693–0.027 molecular cloud covers four different rotational transitions of this molecule, two of which (J = 1–0 and J = 2–1) appear free of contamination from other species. The fit performed, assuming local thermodynamic equilibrium conditions, yields a column density of N=(6.0 \ub1 0.7) 7 1011\ua0cm−2. The resulting molecular abundance with respect to molecular hydrogen is 4.5 7 10–12. The column density of PO+ normalized by the cosmic abundance of P is larger than those of NO+ and SO+, normalized by N and S, by factors of 3.6 and 2.3, respectively. The N(PO+)/N(PO) ratio is 0.12 \ub1 0.03, more than one order of magnitude higher than that of N(SO+)/N(SO) and N(NO+)/N(NO). These results indicate that P is more efficiently ionized than N and S in the ISM. We have performed new chemical models that confirm that the PO+ abundance is strongly enhanced in shocked regions with high values of cosmic-ray ionization rates (10–15 − 10–14 s−1), as occurring in the G+0.693–0.027 molecular cloud. The shocks sputter the interstellar icy grain mantles, releasing into the gas phase most of their P content, mainly in the form of PH3, which is converted into atomic P, and then ionized efficiently by cosmic rays, forming P+. Further reactions with O2 and OH produces PO+. The cosmic-ray ionization of PO might also contribute significantly, which would explain the high N(PO+)/N(PO) ratio observed. The relatively high gas-phase abundance of PO+ with respect to other P-bearing species stresses the relevance of this species in the interstellar chemistry of P

    Precursors of the RNA-world in space: Detection of (ZZ)-1,2-ethenediol in the interstellar medium, a key intermediate in sugar formation

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    We present the first detection of (ZZ)-1,2-ethenediol, (CHOH)2_2, the enol form of glycolaldehyde, in the interstellar medium towards the G+0.693-0.027 molecular cloud located in the Galactic Center. We have derived a column density of (1.8±\pm0.1)×\times1013^{13} cm2^{-2}, which translates into a molecular abundance with respect to molecular hydrogen of 1.3×\times1010^{-10}. The abundance ratio between glycolaldehyde and (ZZ)-1,2-ethenediol is \sim5.2. We discuss several viable formation routes through chemical reactions from precursors such as HCO, H2_2CO, CHOH or CH2_2CHOH. We also propose that this species might be an important precursor in the formation of glyceraldehyde (HOCH2_2CHOHCHO) in the interstellar medium through combination with the hydroxymethylene (CHOH) radical.Comment: Accepted for publication in The Astrophysical Journal Letter

    Advances in structure elucidation of small molecules using mass spectrometry

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    The structural elucidation of small molecules using mass spectrometry plays an important role in modern life sciences and bioanalytical approaches. This review covers different soft and hard ionization techniques and figures of merit for modern mass spectrometers, such as mass resolving power, mass accuracy, isotopic abundance accuracy, accurate mass multiple-stage MS(n) capability, as well as hybrid mass spectrometric and orthogonal chromatographic approaches. The latter part discusses mass spectral data handling strategies, which includes background and noise subtraction, adduct formation and detection, charge state determination, accurate mass measurements, elemental composition determinations, and complex data-dependent setups with ion maps and ion trees. The importance of mass spectral library search algorithms for tandem mass spectra and multiple-stage MS(n) mass spectra as well as mass spectral tree libraries that combine multiple-stage mass spectra are outlined. The successive chapter discusses mass spectral fragmentation pathways, biotransformation reactions and drug metabolism studies, the mass spectral simulation and generation of in silico mass spectra, expert systems for mass spectral interpretation, and the use of computational chemistry to explain gas-phase phenomena. A single chapter discusses data handling for hyphenated approaches including mass spectral deconvolution for clean mass spectra, cheminformatics approaches and structure retention relationships, and retention index predictions for gas and liquid chromatography. The last section reviews the current state of electronic data sharing of mass spectra and discusses the importance of software development for the advancement of structure elucidation of small molecules

    NEOTROPICAL XENARTHRANS: a data set of occurrence of xenarthran species in the Neotropics

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    Xenarthrans – anteaters, sloths, and armadillos – have essential functions for ecosystem maintenance, such as insect control and nutrient cycling, playing key roles as ecosystem engineers. Because of habitat loss and fragmentation, hunting pressure, and conflicts with 24 domestic dogs, these species have been threatened locally, regionally, or even across their full distribution ranges. The Neotropics harbor 21 species of armadillos, ten anteaters, and six sloths. Our dataset includes the families Chlamyphoridae (13), Dasypodidae (7), Myrmecophagidae (3), Bradypodidae (4), and Megalonychidae (2). We have no occurrence data on Dasypus pilosus (Dasypodidae). Regarding Cyclopedidae, until recently, only one species was recognized, but new genetic studies have revealed that the group is represented by seven species. In this data-paper, we compiled a total of 42,528 records of 31 species, represented by occurrence and quantitative data, totaling 24,847 unique georeferenced records. The geographic range is from the south of the USA, Mexico, and Caribbean countries at the northern portion of the Neotropics, to its austral distribution in Argentina, Paraguay, Chile, and Uruguay. Regarding anteaters, Myrmecophaga tridactyla has the most records (n=5,941), and Cyclopes sp. has the fewest (n=240). The armadillo species with the most data is Dasypus novemcinctus (n=11,588), and the least recorded for Calyptophractus retusus (n=33). With regards to sloth species, Bradypus variegatus has the most records (n=962), and Bradypus pygmaeus has the fewest (n=12). Our main objective with Neotropical Xenarthrans is to make occurrence and quantitative data available to facilitate more ecological research, particularly if we integrate the xenarthran data with other datasets of Neotropical Series which will become available very soon (i.e. Neotropical Carnivores, Neotropical Invasive Mammals, and Neotropical Hunters and Dogs). Therefore, studies on trophic cascades, hunting pressure, habitat loss, fragmentation effects, species invasion, and climate change effects will be possible with the Neotropical Xenarthrans dataset
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