Evidence of a new phase in gypsum-anhydrite transformations under microwave heating by in situ dielectric analysis and Raman spectroscopy.

Mineral transformations of the gypsum-anhydrite system under microwave heating have been studied using in situ dielectric thermal analysis (MW-DETA) and Raman spectroscopy simultaneously. The dielectric properties of samples that were measured under microwave heating provided thorough information about the dynamics of the gypsum-anhydrite system transformations and its significance from the mineralogical point of view. In particular, the MW-DETA technique revealed a new intermediate phase with a γ-anhydrite structure. This phase corresponds to the soluble stage of γ-anhydrite, and it is characterized by a high ionic charge inside the crystal channels. The complete sequence is gypsum → 0.625-subhydrate → bassanite → hydro γ-anhydrite → anhydrous γ-anhydrite → ß-anhydrite. The transformations were also assessed using DSC, TG, DTA and dielectric measurements at room temperature, as well as other techniques including X-ray powder diffraction (XRPD) and high-temperature XRD (HT-XRD). Correlations between the dielectric properties with temperature and the rest of the techniques elucidated the heating mechanisms of this material under microwave energy during the different stages. The in situ combination of the MW-DETA and the Raman analysis appears to be a powerful technique, providing new insights about the mechanisms which govern the volumetric heating of this and other materials.

Diagnóstico de hemoglobinopatías a partir de sangre del talón de recién nacidos en diferentes centros hospitalarios de Venezuela / Diagnosis of hemoglobinopathies in newborns in Venezuela hospitals

Objetivos: Las hemoglobinopatías constituyen uno de los desórdenes hereditarios más comunes en humanos, y en Venezuela representan un problema de salud pública. En esta investigación se evaluó la prevalencia de las hemoglobinopatías en neonatos de diferentes áreas de Venezuela, en cooperación con el sistema de cribado neonatal de la Unidad de Estudios de Errores Innatos del Metabolismo del Instituto de Estudios Avanzados. Materiales y métodos: Las muestras de sangre del talón de 101.301 neonatos se estudiaron por medio de la técnica de cromatografía líquida de alta resolución de intercambio catiónico (HPLC-CE), utilizando el equipo Variant® Bio-Rad y los programas Sickle Cell Short para el análisis en papel de filtro y Beta Thal Short para el estudio confirmatorio y familiar. Resultados: Se encontró una alta prevalencia de neonatos heterocigotos para las hemoglobinas (Hb) S y C (Hb S y Hb C). Se observó que el 1,96% (1.989) de los neonatos fueron portadores de alguna variante, y el fenotipo más frecuente fue Hb fetal AS (67,92%), seguido de Hb fetal AC (23,18%), Hb fetal AD (7,49%), Hb fetal SC (0,96%) y Hb fetal SD (0,20%). A todos los niños estudiados (positivos en el cribado), luego de los 3 meses de edad se les confirmó la presencia de alguna variante estructural mediante una segunda prueba confirmatoria. Conclusiones: Las frecuencias de las variantes encontradas en este estudio confirman que las hemoglobinopatías representan un problema de salud pública en Venezuela, y debe enfatizarse la importancia de instaurar en este país un programa de detección sistemática de hemoglobinopatías que comprenda no sólo un tratamiento precoz, sino también un programa de educación y consejo genético para el grupo familiar (AU)

Objectives: Hemoglobinopathies are the most common hereditary disorders in humans representing a public health problem in Venezuela. In this study the prevalence of hemoglobinopathies was evaluated in newborns from different areas of Venezuela, in cooperation with the neonatal screening system of the Study Unit of Inborn Errors of Metabolism (IDEA). Materials and methods: The heel blood samples of 101,301 newborns were analysed by high performance liquid chromatography (HPLC-CE) technique using Variant* Bio Rad System with the Sickle Cell Short program for the filter paper samples in and the Beta Tal Short program for the family studies. Results: We found a high prevalence of newborns heterozygous for hemoglobin S and C (Hb S and Hb C). It was observed that 1.96% (1989) of the newborns were carriers, with Hb FAS (67.92) being the most frequent phenotype, followed by Hb FAC (23.18%), Hb FAD (7.49%), Hb FSC (0.96%),) and Hb FSD (0.20%). All the neonatal positives cases were confirmed at 3 months of age. Conclusions: The frequencies of the variants found in this study confirms that the hemoglobin disorders are a public health problem in Venezuela, emphasizing the importance of instituting a national program of screening for hemoglobinopathies throughout the country, comprising not only an early treatment, but also an educational program and genetic counseling for the family group (AU)

[Diagnosis of hemoglobinopathies in newborns in Venezuela hospitals]. / Diagnóstico de hemoglobinopatías a partir de sangre del talón de recién nacidos en diferentes centros hospitalarios de Venezuela.

OBJECTIVES: Hemoglobinopathies are the most common hereditary disorders in humans representing a public health problem in Venezuela. In this study the prevalence of hemoglobinopathies was evaluated in newborns from different areas of Venezuela, in cooperation with the neonatal screening system of the Study Unit of Inborn Errors of Metabolism (IDEA). MATERIALS AND METHODS: The heel blood samples of 101,301 newborns were analysed by high performance liquid chromatography (HPLC-CE) technique using Variant* Bio Rad System with the Sickle Cell Short program for the filter paper samples in and the Beta Tal Short program for the family studies. RESULTS: We found a high prevalence of newborns heterozygous for hemoglobin S and C (Hb S and Hb C). It was observed that 1.96% (1989) of the newborns were carriers, with Hb FAS (67.92) being the most frequent phenotype, followed by Hb FAC (23.18%), Hb FAD (7.49%), Hb FSC (0.96%),) and Hb FSD (0.20%). All the neonatal positives cases were confirmed at 3 months of age. CONCLUSIONS: The frequencies of the variants found in this study confirms that the hemoglobin disorders are a public health problem in Venezuela, emphasizing the importance of instituting a national program of screening for hemoglobinopathies throughout the country, comprising not only an early treatment, but also an educational program and genetic counseling for the family group.

Asociación de encefalomielitis aguda diseminada y virus de Epstein-Barr / Acute disseminated encephalomyelitis secondary to Epstein-Barr virus

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Síndrome hemolítico-urémico secundario a neumonía por Streptococcus pneumoniae / Hemolytic uremic syndrome secondary to Streptococcus pneumoniae pulmonary infection

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