Effect of land use and soil properties in the feasibility of two sequential extraction procedures for metals fractionation.

Several sequential extraction procedures are widely applied for metals chemical fractionation in the literature. However, their limitations to be used in different soils and metals have not been discussed in detail. This study compares two of the most commonly used extraction methods for metals chemical fractionation: Tessier and BCR. The objectives were to i) assess the differences between concentrations of metals extracted in each fraction by both Tessier and BCR procedures; ii) elucidate if soil properties affected the extraction ability of each fraction from both procedures; and iii) evaluate how land use contributes to different chemical metal distribution. Results indicated that both methods provide similar results when were applied to the same soil, since non-significant differences were found in metal concentrations between both methods at each fraction. Conversely, when we compared among land uses, significant differences were found in the metal concentration between both methods, especially between agricultural/urban/industrial against forest soil. Redundancy analysis showed that in carbonate-rich soils, BCR extraction method could cover up the real concentration of exchangeable metals with those bound to the carbonate phase, being the Tessier method the most suitable one for this kind of soils. Therefore, although sequential extraction is a useful tool to understand the distribution of metals in soil, the method used must be selected according to the land use and specific soil characteristics, taking into account at least, soil carbonate content.

Falla cardíaca avanzada en pacientestratados con dispositivos electrofisiológicos en una unidad de electrofisología, Pereira (Colombia) / Patients with advanced heart failure treated with electrophysiological devices in an electrophysiology center, Pereira(Colombia)

Resumen: la falla cardíaca avanzada es una enfermedad prevalente, con una tasaalta de mortalidad y hospitalización con relación a su estadio y perfil clínico, quecuesta en Norteamérica hasta el 20 por ciento de los recursos destinados para el manejo de la enfermedad cardiovascular. Se realizó un análisis transversal a una cohorte de 70 pacientes en tratamiento farmacológico y cardioresincronizador con o sin cardiodesfibirlador, o solo cardiodesfibrilador automático (ICD) implantado entre los años 2010 y 2012.Métodos: el presente es un estudio transversal. Resultados: 71 por ciento presentaron hipertensión arterial HTA; 65,75 por ciento cardiopatía isquémica, siendo el 58.3 por ciento portadores de resincronizador con o sin cardiodesfibrilador. El 90 por ciento de los pacientes tiene 2 o más medicamentos, 77 por ciento betabloqueador, 90 por ciento iECA o ARA II, 85.7 por ciento algún diurético.Conclusión: se caracterizaron los pacientes que recibieron terapia electrofisiológica para manejo avanzado de falla cardíaca.