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The article presents a study which examines the amount to circulate hemopoietic progenitors cells (HPC) in chronic lymphocytic leukemia (CLL) peripheral blood (PB) samples with various CD49d expression levels. Immunophenotpic characterization of HPC was done by examining the lineage-specific antigens' expression and surface molecules mediating cell-matrix and cell-cell interactions. The differences in the amount of circulating CD23+ cells were not discovered by comparing CLL cases.

This work is concerned to study the sintering rate and mass transport mechanism in ceramic engobes. Specimens of engobes were prepared from a determined formulation by slip casting. Sintering was carried in two steps: (i) at constant heating rate of 7.5 ºC/min and (ii) with an isothermal treatment, during 120 min. According to the dilatometric curves obtained with the engobe sintering during isothermal treatment, the dominant sintering mechanism and the rate of reactions, between the 775 and 975 ºC, were determined. The results showed that between 775 and 800 ºC, the sintering rate can be described by ln[d(ΔL/L0)/dt] = -5.64 + 1.77·10-3T. At higher temperatures, from 850 to 975 ºC, this rate can be expressed by ln[d(ΔL/L0)/ dt] = -30.73 + 3·10-2T. The dominant transport mass mechanisms were the grain rearrangement, solution-precipitation and grain boundaries reaction.En este trabajo se estudiaran la cinética de sinterización y los mecanismos de transferencia de masa en engobes cerámicos. Para eso, fueron preparados cuerpos de prueba de una formulación de engobe, conformados por colaje y luego sometidos a un tratamiento térmico realizado en dos etapas: (i) con velocidad de calentamiento constante a 7,5 ºC/min y (ii) con un tratamiento isotérmico, durante 120 min. Mediante las curvas dilatométricas obtenidas de la sinterización del engobe, durante el tratamiento isotérmico de 120 min, se determinó el mecanismo de sinterización dominante y la velocidad de las reacciones, en un rango de temperatura entre 775 y 975 ºC. Los resultados mostraron que, en el rango de 775 a 800 ºC, la velocidad de sinterización con la temperatura puede ser representada por la ecuación ln[d(ΔL/L0)/dt] = -5,64 + 1,77.10-3T, mientras que a temperaturas más altas, entre 850 y 975 ºC, esta velocidad pudo ser expresa por la ecuación ln[d(ΔL/L0)/dt] = -30,73 + 3.10-2T. Los mecanismos de transferencia de masa obtenidos fueron de reordenamiento de granos, reacción soluciónprecipitación y reacción en borde de grano.

This paper analyses the effect of cooling on mechanical behaviour, in particular, on the residual stresses that appear when materials of the porcelain tile type are involved. However, these compositions have a very complex microstructure, in which there are several crystalline phases and the glassy phase is not homogeneous. In this study a simpler composition was therefore formulated, using sodium feldspar as starting material to which quartz with different particle sizes was added. A viscoelastic model was used to estimate the residual stresses that develop during cooling. The parameters of the model were obtained either from the literature or were determined in laboratory tests. An assembly was designed that allowed non-contact measurement of the temperature at the top and bottom surfaces of the test pieces during cooling. The test pieces were subjected to different types of cooling and their residual stresses were then determined by the strain relaxation slotting method.En este trabajo se analiza el efecto del enfriamiento sobre el comportamiento mecánico y, en particular, sobre las tensiones residuales que aparecen cuando se trabaja con materiales tipo gres porcelánico. Estas composiciones tienen una microestructura muy compleja, donde se encuentran varias fases cristalinas y la fase vítrea dista de ser homogénea. Por ello se planteó trabajar con una composición más sencilla, empleando como material de partida feldespato sódico al que se añadió cuarzo de diferente tamaño de partícula. Se utilizó un modelo viscoelástico para la estimación de las tensiones residuales que se producen durante el enfriamiento. Los parámetros del modelo se obtuvieron de la bibliografía o se determinaron en ensayos de laboratorio. Se diseñó un montaje que permitía la medida sin contacto de la temperatura en las superficies superior e inferior de la pieza durante el enfriamiento. Las probetas fueron sometidas a diferentes tipos de enfriamientos y, a continuación, se determinaron las tensiones residuales mediante el método de relajación de las deformaciones por corte.

B-cell chronic lymphocytic leukemia (CLL), the most frequent leukemia in the Western world, is characterized by extremely variable clinical courses with survivals ranging from 1 to more than 15 years. The pathogenetic factors playing a key role in defining the biological features of CLL cells, hence eventually influencing the clinical aggressiveness of the disease, are here divided into "intrinsic factors", mainly genomic alterations of CLL cells, and "extrinsic factors", responsible for direct microenvironmental interactions of CLL cells; the latter group includes interactions of CLL cells occurring via the surface B cell receptor (BCR) and dependent to specific molecular features of the BCR itself and/or to the presence of the BCR-associated molecule ZAP-70, or via other non-BCR-dependent interactions, e.g. specific receptor/ligand interactions, such as CD38/CD31 or CD49d/VCAM-1. A putative final model, discussing the pathogenesis and the clinicobiological features of CLL in relationship of these factors, is also provided. [ABSTRACT FROM AUTHOR]