21,132 research outputs found

    Survival Probability in Patients with Sickle Cell Anemia Using the Competitive Risk Statistical Model.

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    The clinical picture of patients with sickle cell anemia (SCA) is associated with several complications some of which could be fatal. The objective of this study is to analyze the causes of death and the effect of sex and age on survival of Brazilian patients with SCA. Data of patients with SCA who were seen and followed at HEMORIO for 15 years were retrospectively collected and analyzed. Statistical modeling was performed using survival analysis in the presence of competing risks estimating the covariate effects on a sub-distribution hazard function. Eight models were implemented, one for each cause of death. The cause-specific cumulative incidence function was also estimated. Males were most vulnerable for death from chronic organ damage (p = 0.0005) while females were most vulnerable for infection (p=0.03). Age was significantly associated (p ≤ 0.05) with death due to acute chest syndrome (ACS), infection, and death during crisis. The lower survival was related to death from infection, followed by death due to ACS. The independent variables age and sex were significantly associated with ACS, infection, chronic organ damage and death during crisis. These data could help Brazilian authorities strengthen public policies to protect this vulnerable population

    Yield, foliar concentration, and efficiency of extractant solutions with boron application in a Xanthic Ferralsol cultivated with banana in Central Amazon.

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    Boron is known to play important role in the structure of cell wall, membranes, and membrane-associated functions in plants. In soil, the hot water B extraction method has been extensively used, however, difficulties with this procedure result in low accuracy and precision of extraction of available boron (B) in soil. The objective of this study was to evaluate the Yield, foliar concentration, and efficiency of B extracting solutions and the effect of B fertilization on B uptake in banana leaves and fruits, subgroup Cavendish (AAA), cultivated in a Xanthic Ferralsol (dystrophic Yellow Latosol), in the Amazonas State, Brazil. The experimental design was a completely randomized split plot, comprising four boron rates (0, 4, 8, and 12 kg ha-1), and two harvest cycles (subtreatments), with four replicates. Available boron was determined with seven extractant solutions: Mehlich 1, Mehlich 3, hot water, HCl 0.05 mol L-1, HCl 0.1 mol L-1, HCl 5.0 mol L-1 and KCl 1.0 mol L-1. The application of B fertilizer increased the yield and concentration of B in leaves and fruits. Hot water and KCl 1.0 mol L-1 were the most efficient extracting solutions for the determination of available B in soil. The application of 3.4 kg B ha-1 in first cycle and 1.3 kg B ha-1 in second cycle guarantees an adequate nutritional status in banana plants.Paper 1054

    Determination of Arsenic, Mercury and Barium in herbarium mount paper using dynamic ultrasound-assisted extraction prior to atomic fluorescence and absorption spectrometry

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    A dynamic ultrasound-assisted extraction method using Atomic Absorption and Atomic Flourescence spectrometers as detectors was developed to analyse mercury, arsenic and barium from herbarium mount paper originating from the herbarium collection of the National Museum of Wales. The variables influencing extraction were optimised by a multivariate approach. The optimal conditions were found to be 1% HNO3 extractant solution used at a flow rate of 1 mL min-1. The duty cycle and amplitude of the ultrasonic probe was found to be 50% in both cases with an ultrasound power of 400 W. The optimal distance between the probe and the top face of the extraction chamber was found to be 0 cm. Under these conditions the time required for complete extraction of the three analytes was 25 min. Cold vapour and hydride generation coupled to atomic fluorescence spectrometry was utilized to determine mercury and arsenic, respectively. The chemical and instrumental conditions were optimized to provide detection limits of 0.01ng g-1 and 1.25 ng g-1 for mercury and arsenic, respectively. Barium was determined by graphite-furnace atomic absorption spectrometry, with a detection limit of 25 ng g-1. By using 0.5 g of sample, the concentrations of the target analytes varied for the different types of paper and ranged between 0.4–2.55 µg g-1 for Ba, 0.035–10.47 µg g-1 for As and 0.0046–2.37 µg g-1 for Hg
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