RESUMEN
The aim of this paper is to compare the fluoride-releasing and mechanical properties of an experimental luting glass ionomer cement, which has a modified composition and a commercial luting cement. The experimental powder was obtained by sol-gel process and then, it was used to prepare the experimental cements. The properties of cement pastes, such as setting time and working time, microhardness and diametral tensile strength were determined. Fluoride release from GICs was evaluated at time intervals of 1, 7, 14, 21 and 28 days in deionized water. Atomic force microscopy (AFM) analyses showed that the surface of the experimental cements is more homogeneous than commercial GICs. The mechanical properties and the measure of liberation of fluoride of the two cements were influenced by ratio powder:liquid and chemical composition of the precursor powders. Experimental cements released less fluoride than commercial cements. However, this liberation was more constant during the analyzed period. Thus, the results obtained in this study indicated that the composition of the experimental powder modified by the niobium can lead the formation of the polysalt matrix with good mechanical properties. In other words, we can say that experimental powder offered considerable promise for exploitation in dental field.
Asunto(s)
Cementos Dentales/química , Cementos de Ionómero Vítreo/química , Fuerza Compresiva , Odontología/métodos , Diseño de Equipo , Dureza , Ensayo de Materiales , Microscopía de Fuerza Atómica/métodos , Niobio/química , Polvos , Estrés Mecánico , Temperatura , Resistencia a la Tracción , Factores de Tiempo , Difracción de Rayos XAsunto(s)
Proteínas Sanguíneas/aislamiento & purificación , Electroforesis de las Proteínas Sanguíneas , Precipitación Química , Cromatografía por Intercambio Iónico , Etanol , Factor IX , Fibronectinas , Congelación , Humanos , Indicadores y Reactivos , Plasminógeno , Desnaturalización Proteica , Protrombina , Albúmina Sérica/aislamiento & purificación , SolventesRESUMEN
The use of high-performance liquid chromatography (HPLC) with size exclusion column packings is investigated as an alternate assay method to the analytical ultracentrifuge, when assaying for the high molecular weight components of human plasma protein fraction. Results indicate that HPLC is a more accurate and precise method for assaying high molecular weight components in plasma protein fraction, even when present in small amounts.
Asunto(s)
Proteínas Sanguíneas/análisis , Peso Molecular , Cromatografía Líquida de Alta Presión/métodos , Humanos , Factores de Tiempo , Ultracentrifugación/métodosRESUMEN
Commercially prepared fraction V products (5 and 25% albumin and 5% plasma protein fraction) and immune serum globulins were subjected to analytical molecular sieve chromatography by high performance liquid chromatography. Quantitation was performed by UV absorbance and by the Lowry protein assay. The proteins eluting in the void volume from the immune serum globulin samples yield equivalent results by UV absorbance and by Lowry assay. Proteins eluting in the void volume from fraction V products indicate approximately twice as much protein by UV absorbance when compared to Lowry protein assay.
Asunto(s)
Proteínas Sanguíneas/análisis , Fraccionamiento Químico , Cromatografía en Gel , Cromatografía Líquida de Alta Presión , Colorimetría , Humanos , Inmunoglobulinas/análisis , Peso Molecular , Espectrofotometría Ultravioleta , UltracentrifugaciónRESUMEN
Various lots of human serum albumin, prepared by the Cohn alcohol procedure, were assayed for polymer distribution after lyophilization or acetone drying of the albumin paste. Sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed that powders obtained by acetone drying of the pastes contained significantly higher amounts of monomeric albumin.
