Browsing by Author "Aguilar, C"

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    Effectiveness of shrinkage-reducing admixtures on Portland pozzolan cement concrete
    (CONSEJO SUPERIOR INVESTIGACIONES CIENTIFICAS-CSIC, 2005) Videla, C; Aguilar, C
    Drying shrinkage causes tensile stress in restrained concrete members. Since all structural elements are subject to some degree of restraint, (trying shrinkage is regarded to be one of the main causes of concrete cracking.
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    Nutritional evaluation of diets. Simulation model of digestion and passage of nutrients through the rumen-reticulum
    (ELSEVIER SCIENCE BV, 1997) Chilibroste, P; Aguilar, C; Garcia, F
    To evaluate the nutritional behaviour of simple and complex diets provided under different feeding regimes, a stochastic, dynamic and predictive simulation model was developed. Feed fractions, considered in the model were soluble non-structural carbohydrates (SNSC), insoluble non-structural carbohydrates (INSC), INSC degradation rate (kd(INSC)), fractional passage rate (kp), neutral detergent fibre (NDF), NDF potentially digestible (PNDF), PNDF degradation rate (kd(PNDF)), soluble crude protein (SCP), insoluble crude protein (ICP), ICP potentially degradable (PICP), and PICP degradation rate (kd(PICP)). Animal characteristics considered in the model, were live weight and physiological status (lactation and/or pregnancy). Variables inherent to management practices were amounts and schedule of DM offered to the animals. The model was subjected to validation for a wide range of experimental conditions. Predictions of total Dh? and forage DM intakes (and therefore the estimate of the substitution of forage for concentrate) had an R-2 = 0.95 and 0.92, respectively. Prediction of NDF digestibility had an R-2 = 0.61 in a smaller range of experimental conditions. (C) 1997 Elsevier Science B.V.
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    Oxalate oxidase from Ceriporiopsis subvermispora
    (1999) Aguilar, C; Urzúa, U; Koenig, C; Vicuña, R
    The enzyme oxalate oxidase was identified in mycelial extracts of the basidiomycete Ceriporiopsis subvermispora and thereafter purified to homogeneity. The purification procedure included only three steps: Q-Sepharose chromatography, precipitation at pH 3.0, and phosphocellulose chromatography. The enzyme is a 400-kDa homohexamer, as determined by gel permeation in Sephadex G-200 and SDS-polyacrylamide gel electrophoresis. Isoelectrofocusing revealed a pi of 4.2. Optimal activity was obtained at pH 3.5 and at 45 degrees C. The purified enzyme has K-m and k(cat) values of 0.1 mM and 88 s(-1), respectively. It is highly specific for oxalate, although it is inhibited at concentrations of this substrate above 2.5 mM. Hystochemistry studies conducted over mycelium slices showed reactions products in both endocellular and periplasmic associated elements. A possible connection between the intracellular metabolism of oxalate and the extracellular ligninolytic activity of the fungus is proposed. (C) 1999 Academic Press.