RESUMEN
BACKGROUND: The urine dipstick is widely used as an initial screening tool for the evaluation of proteinuria; however, its diagnostic accuracy has not yet been sufficiently evaluated. Therefore, we evaluated its diagnostic accuracy using spot urine albumin/creatinine ratio (ACR) and total protein/creatinine ratio (PCR) in proteinuria. METHODS: Using PCR ≥0.2 g/g or ≥0.5 g/g and ACR ≥300 mg/g or ≥30 mg/g as the reference standard, we calculated the diagnostic accuracy profile: sensitivity, specificity, positive and negative predictive value, and the area under the curve (AUC) of the receiver operating characteristic curve. RESULTS: PCR and ACR were available for 10,348 and 3,873 instances of dipstick testing. The proportions with PCR ≥0.2 g/g, ≥0.5 g/g and ACR ≥300 mg/g, ≥30 mg/g were 38.2%, 24.6% and 8.9%, 31.7%, respectively. The AUCs for PCR ≥0.2 g/g, ≥0.5 g/g, and ACR ≥300 mg/g were 0.935 (trace: closest to ideal point), 0.968 (1+), and 0.983 (1+), respectively. Both sensitivity and specificity were >80% except for PCR ≥0.5 g/g with trace cutoff. For the reference standard of ACR ≥30 mg/g, the AUC was 0.797 (trace) and the sensitivity was 63.5%. CONCLUSION: Urine dipstick test can be used for screening in older outpatients with ACR ≥300 mg/g or PCR as the reference standard for proteinuria. However, we cannot recommend the test as a screening tool with ACR ≥30 mg/g as the reference owing to its low sensitivity.
RESUMEN
In this study, the transformation of 1-naphthol via oxidative-coupling reaction was investigated using Mn oxides. 1-Naphthol was transformed completely by birnessite, which is one of the natural Mn oxides present in soil. The surface area-normalized specific rate constant, k(surf), for 1-naphthol was determined to be 9.66 x 10(-4)L/m(2)min using observed pseudo-first-order rate constants with respect to birnessite loading. The transformation of 1-naphthol was dependent on the solution pH, and the pseudo-first-order rate constants increased from 0.028 at pH 11 to 0.075 at pH 2 at a birnessite loading of 0.625 g/L. GC and LC mass spectroscopic analysis of the supernatants were performed after separating the reaction solution into hydrophobic and hydrophilic fractions by solvent extraction. The major transformation products were found to be 1,4-naphthoquinone(1,4-NPQ) and naphthol polymerized products with a molecular weight (m/z) ranging from 400 to 2000. Transformation of 1,4-NPQ, to the polymerized products by an additional birnessite loading was also verified. The DOC concentrations of the supernatants before and after the reaction were analyzed and the rate of oligomeric precipitate formation was measured.
Asunto(s)
Compuestos de Manganeso/química , Naftoles/química , Óxidos/química , Fenómenos Químicos , Precipitación Química , Restauración y Remediación Ambiental/métodos , Cinética , Oxidación-Reducción , SolucionesRESUMEN
In this study, removals of 1-naphthol by oxidative-coupling reaction using birnessite, one of the natural Mn oxides present in soil, was investigated in various experimental conditions (reaction time, Mn oxide loadings, pH). The removal efficiency of 1-naphthol by birnessite was high in all the experimental conditions, and UV-visible and mass spectrometric analyses on the supernatant after reaction confirmed that the reaction products were oligomers formed by oxidative-coupling reaction. Pseudo-first order rate constants, k, for the oxidative transformation of 1-naphthol by birnessite was derived from the kinetic experiments under various amounts of birnessite loadings, and using the observed pseudo-first order rate constants with respect to birnessite loadings, the surface area normalised specific rate constant, k(surf), was also determined to be 9.3 x 10(-4) (L/m(2).min) for 1-naphthol. In addition, the oxidative transformation of 1-naphthol was found to be dependent on solution pH, and the pseudo-first order rate constants were increased from 0.129 at pH 10 to 0.187 at pH 4.
Asunto(s)
Compuestos de Manganeso , Óxidos , Hidrocarburos Policíclicos Aromáticos/aislamiento & purificación , Cromatografía Líquida de Alta Presión , Cromatografía Liquida , Indicadores y Reactivos , Cinética , Espectrometría de Masas , Naftoles , Oxidación-Reducción , Espectroscopía Infrarroja por Transformada de Fourier , Propiedades de Superficie , Purificación del Agua/métodosRESUMEN
Abiotic transformation of TNT reduction products via oxidative-coupling reaction was investigated using Mn oxide. In batch experiments, all the reduction products tested were completely transformed by birnessite, one of natural Mn oxides present in soil. Oxidative-coupling was the major transformation pathway, as confirmed by mass spectrometric analysis. Using observed pseudo-first-order rate constants with respect to birnessite loadings, surface area-normalized specific rate constants, ksurf, were determined. As expected, ksurf of diaminonitrotoluenes (DATs) (1.49-1.91L/m2 d) are greater about 2 orders than that of dinitroaminotoluenes (DNTs) (1.15 x 10(-2)-2.09 x 10(-2)L/m2d) due to the increased number of amine group. In addition, by comparing the value of ksurf between DNTs or DATs, amine group on ortho position is likely to be more preferred for the oxidation by birnessite. Although cross-coupling of TNT in the presence of various mediator compounds was found not to be feasible, transformation of TNT by reduction using Fe0 followed by oxidative-coupling using Mn oxide was efficient, as evaluated by UV-visible spectrometry.