RESUMEN
A very stable chelating resin was prepared by adsorption of (o-[3,6-disulfo-2-hidroxy-1-naphthylazo]-benzenearsonic acid) (thorin) on a macroporous resin Amberlite XAD-7. The optimal conditions for preparing it were obtained through the study of the adsorption properties of the resin and the thermodynamic quantities of the adsorption processes. Likewise, the behavior of the loaded resin with the rare earth elements (REE) were studied (pH of retention, sorption kinetics, etc). The conditions to prepare a thin film with this system were also evaluated. The loaded resin was successfully used for the separation and preconcentration of Sm(III), Eu(III) and Gd(III) prior to their determination by X-ray fluorescence (XRF) spectrometry. The preconcentration factor obtained was 500 and the concentrations at low detection limit were 13.8, 17 and 15.7 microg l(-1) for Sm, Eu and Gd, respectively.
RESUMEN
8-Quinolinol (oxine) and 2-(2-(5 chloropyridylazo)-5-dimethylamino)-phenol (5ClDMPAP) were immobilized on the non ionic sorbents Amberlite XAD-4 and XAD-7. These loaded resins were used for the preconcentration of Ce, La and Pr. High preconcentration factors were obtained in each case. After the retention of these rare earths, the resins were measured as thin films by x-ray fluorescence spectrometry. Up to 50 ppm of REEs can be retained on these thin films.
RESUMEN
We studied 120 first-degree relatives (FDRs) of 25 systemic lupus erythematosus (SLE) probands and 59 non-genetically associated individuals who were in close contact with the SLE patients. A significantly greater frequency of antinuclear antibody (ANA) positivity was found among the FDRs than in the control group (p less than 0.01). No significant difference was found in ANA positive between the female and male FDRs. Articular complaints or Raynaud's phenomenon were observed in 15% of the FDRs and in only 2% of the controls (p less than 0.05). Female FDRs had a greater number of rheumatic complaints than male FDRs (p less than 0.05) and a significant association was found between rheumatic complaints and ANA positivity (p less than 0.001) among the total FDRs.