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  • Author or Editor: J. López-González x
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Abstract  

In the present work a study was made for determining colour intensities using as luminous non-monochromatic source the Cherenkov emission produced in the walls of a glass capillary which acts as luminous source itself inside of a coloured solution to be evaluated. The reproducibility of this method has been compared with the spectrophotometric assay; the relative errors of both analytical methods have been calculated for different concentrations of congo red solution in the range of minimal error, according to Ringbom's criterion. The sensitivity of this analytical method has been studied for the two β-emitters employed:90Sr/90Y and204Tl.

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Salts [XanH+]2[MCl

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In vitro androgenesis allows haploid and double haploid homozygous plants to be obtained. However, in cereals, non-viable albino plants are often produced. This limits the use of this technique both in basic studies and in plant genetic improvement programs. We have analyzed eight microsatellites of the chloroplast genome (cpSSR) in a collection of 46 double haploid green lines derived from the intervarietal hybrid ‘Torote’ × ‘Presto’, and 49 haploid albino plants all obtained from the double haploid line ‘ATOPE-41’, in order to know the stability of this sequences after the androgenetic process. The green plants showed no variations at the analyzed loci, while two of the albino plants differed at two loci: WCt2 and WCt9. These variations notably affected the microsatellite nucleotide sequences as well as the sequences surrounding them. The changes observed consisted of insertions, deletions and nucleotide substitutions, with transition and transversion types equally common. The latter albino plants showed several alleles at the polymorphic loci, indicating the existence of heteroplasmy.

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Abstract  

The precipitation of uranyl ion with 2-hydroxy-1-naphthaldehyde /2H–1N=HL/ was studied. The solid complex /orange crystals/ was characterized by IR, UV-Vis spectra. Uranium was determined as U3O8 after calcination of the complex at 850°C /37.78% U experimental, 36.64% U calculated for C22H14O6U, UO2L2/. Using a statistical experimental design, the best conditions for quantitative precipitation were obtained. A gravimetric method for the determination of UO 2 2+ is proposed by weighing the complex after drying at 110°C.

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Journal of Thermal Analysis and Calorimetry
Authors: G. Vázquez, F. López-Suevos, J. González-Alvarez, and G. Antorrena

Summary  

Phenol-urea-formaldehyde-tannin (PUFT) adhesives have been prepared by copolymerization at room temperature of pine bark tannins with phenol-urea-formaldehyde (PUF) prepolymers prepared under varying operating conditions. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) have been used to analyse the curing of prepolymers and adhesives. DSC curves were obtained at three different heating rates and, by means of the Model Free Kinetics isoconversional method, chemical conversion vs. time at a given temperature was obtained. Mechanical conversion was calculated from DMA storage modulus data for those adhesives which gave the best results for plywood and MDF boards.

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Journal of Thermal Analysis and Calorimetry
Authors: J. Salas-Peregrin, M. Moreno-Carretero, J. Lopez-Gonzalez, and C. Valenzuela-Calahorro
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Abstract  

The catalytic behaviour of ceria, zirconia and ceria–zirconia mixed oxides in the temperature-programmed degradation of toluene and n-hexane was analysed by means of evolved gas analysis (mass spectrometry). Pure cerium oxide resulted the most active catalyst in the oxidation of both compounds. This fact revealed the crucial role of the surface oxygen species in the decomposition of this type of hydrocarbons. The low affinity of CeO2 for H2O and CO2, the major oxidation products, may be also responsible for the observed highly active catalytic behaviour.

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Summary The catalytic properties of ceria-zirconia mixed oxides have been characterized using temperature-programmed techniques such as temperature-programmed desorption of ammonia and water, and temperature-programmed reduction with hydrogen. The acidity and hydrophobicity of these materials increased with zirconia content while the reducibility was maximum for Ce0.5Zr0.5O2 sample.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: G. Ferro-Flores, L. García-Salinas, M. Pedraza-López, M. González-Zavala, J. Tendilla, and M. López-Gómez

Abstract  

A new type of preparation employing153Sm metallic-hydroxide macroaggregates (153Sm-MHM) for radiation synovectomy was developed. The radiopharmaceutical was prepared by reacting the aqueous solution of153SmCl3 with sodium borohydride solution in 0.5N NaOH. Microscopic analysis showed that153Sm-MHM mean particle size was 4 m (range 1–15 m) avoiding the formation of fine particles (<1 m) which were153Sm-hydroxide macroaggregates preparations (153Sm-HM). Also, suspension properties as sedimentation rate, were better for153Sm-MHM than for153Sm-hydroxyapatite and153Sm-HM. Biological studies in normal rabbits demonstrated high retention into de Knee joint space even at 48 h after administration of153Sm-MHM (>99%).

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