RESUMEN
The removal of methylene blue (MB), a cationic dye and orange II (OII), an anionic dye, from aqueous solution by using carbon nanomaterials as multiwalled carbon nanotubes (MWNTs) and carbon nanofibers (CNF) as adsorbents was studied in batch experiments. The effect of pH, temperature and surface modification of adsorbent on the removal of MB and OII was also investigated. The removals of OII and MB by adsorption on MWNT were maximum at pH 3.0 and pH 7.0, respectively. However, in the case CNF was employed as adsorbent, the optimum values of pH were 9.0 and 5.0 for OII and MB, respectively. Langmuir and Freundlich isotherms are applied to fit the adsorption data of both dyes. Equilibrium data were well described by the typical Langmuir adsorption isotherm. Overall, the study demonstrated that MWNTs and CNFs can effectively remove cationic and anionic dyes as MB and OII from aqueous solutions under these experimental conditions.
Asunto(s)
Colorantes/química , Nanotubos de Carbono/química , Adsorción , Compuestos Azo/química , Bencenosulfonatos/química , Concentración de Iones de Hidrógeno , Azul de Metileno/química , Microscopía Electrónica de Rastreo , Nanofibras/química , Nanofibras/ultraestructura , Nanotecnología/métodos , Nanotubos de Carbono/ultraestructura , Temperatura , Contaminantes Químicos del Agua/químicaRESUMEN
Degradation of several azo dyes, Acid Orange 7 (AO7), Acid Orange 74 (AO74), Direct Blue 71 (DB71), Reactive Black 5 (RB5) and Eriochrome Blue Black B (EBBB), well-known non-biodegradable mono, di and tri azo dyes has been studied using, wet-air oxidation (WAO) and catalytic wet air oxidation (CWAO). The efficiency of substrate decolorization and mineralization in each process has been comparatively discussed by evolution concentration, chemical oxygen demand, total organic carbon content and toxicity of dyes solutions. The most efficient method on decolorization and mineralization (TOC) was observed to be CWAO process. Mineralization efficiency with wet air and catalytic wet air oxidation essays was observed in the order of mono-azo > di-azo > tri-azo dye. Final solutions of CWAO applications after 180 min treatment can be disposed safely to environment.
Asunto(s)
Aire , Compuestos Azo/química , Colorantes/química , Eliminación de Residuos Líquidos/métodos , Purificación del Agua/métodos , Catálisis , Color , Oxidación-Reducción , Oxígeno/aislamiento & purificación , Factores de Tiempo , Pruebas de ToxicidadRESUMEN
Los recien nacidos (RN) de muy bajo peso (<_1500G) constituyen alrededor del 2 por ciento del total de recién nacidos vivos, y son la población neonatal más vulnerable, con elevadas tasas de morbimortalidad. Conocer la incidencia, evolución nutricional, morbilidad y mortalidad de esta población en 5 hospitales, uno localizado en Lima y los otros 4 en provincias. De ellos 3 hospitales pertenecen al Ministerio de Salud y 2 a la Seguridad Social. Se estudiaron todos los RN durante el año 1999 en los hospitales del Ministerio de Salud (MINSA) localizados en Tacna, Trujillo e Iquitos, y en los de la Seguridad social (EsSalud) del Cusco y Lima (Rebagliati). Se elaboró un protocolo y una ficha de recolección de datos. Una vez recolectada la información se llevó ésta a una base de datos Excel (Microsoft) y luego se hizo la valoración estadística. Se estudiaron 17,723 RN, encontrándose una incidencia promedio de 1.55 por ciento de RN de muy bajo peso. las morbilidades predominantes fueron el síndrome de dificultad respiratoria, problemas metabólicos, hemorragia intracraneana y sepsis. La evolución nutricional sólo se estudió en los Hospitales Belén y Rebagliati. La supervivencia fue de 44.7 por ciento, siendo la mortalidad muy elevada en los <_ 1000g de peso al nacer y <_ 28 semanas de edad gestacional. Las causas principales de muerte fueron asfixia, membrana hialina y sepsis. Se ratifica la elevada proporción de RN de muy bajo peso fallecidos. La mortalidad fue mayor en hospitales de provincia y en los pertecientes al MINSA, se requiere establecer estrategias nacionales consensuales para un manejo adecuado de este grupo de recién nacidos.
Asunto(s)
Recien Nacido Prematuro , Morbilidad , Mortalidad , Recién Nacido de muy Bajo PesoRESUMEN
OBJECTIVE: After the initial description of the anticardiolipin syndrome inpatients with systemic lupus erythematosus (SLE), it became clear that phospholipids other than cardiolipin could also be involved, that there could also be a primary syndrome, and that protein cofactors participate in in vitro reactivity of the autoantibodies. We describe 5 patients with SLE with clinical manifestations of antiphospholipid syndrome (APS) but persistently negative antiphospholipid antibodies (aPL). In all their tested sera we found antibodies to phospholipid-free beta 2-glycoprotein I (a beta 2-GPI). METHODS: We studied 5 patients with SLE with at least 2 clinical manifestations of APS with no serum aPL detected in routine assays. IgG and IgM a beta 2-GPI were studied by ELISA and by Western blot. We also tested for antibodies to phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine by ELISA. We studied 54 normal sera as controls. RESULTS: Four patients had livedo reticularis, 2 had thrombocytopenia, 2 had hemolytic anemia, and one each had recurrent venous thromboses, repeated fetal loss, pulmonary arterial hypertension, and transverse myelitis. No patient had serum aPL, but all had high titers of IgG a beta 2-GPI (p < 0.001 vs controls). Reactivity found in ELISA was confirmed by Western blot. CONCLUSION: We describe a variant of APS in patients with SLE with negative aPL but serum antibodies to beta 2-GPI.