Predicting 24-hour urinary sodium excretion in Afro-Caribbean Barbadians by comparing urine sodium excretion over different durations versus spot collection / Predicción de la excreción del sodio urinario de 24 horas en Barbadenses Afrocaribeños mediante la comparación de la excreción del sodio en la orina en diferentes periodos de tiempo en contraste con la eecogida al azar

AIM: Urinary sodium excretion is used as an assessment tool for salt intake and salt handling. Even though cumbersome, the most reliable and readily used method in clinical and epidemiological studies is the 24-hour urine collection. This study investigates other appropriate means of predicting 24-hour urinary sodium excretion in a sample of Afro-Caribbeans in Barbados by assessing the correlation of actual and estimated urinary sodium excretion between a 24-hour urine collection sample, 12-hour (AM and PM), and spot (AM and PM) urine collections. METHOD: A convenient sample of 30 healthy participants of Afro-Caribbean origin between the ages of 21 and 55 years was recruited for the study. The 24-hour urine samples and anthropometric data were collected as documented in the study's standard clinical procedure. A 24-hour urine sample was collected as two separate 12-hour AM and PM samples. In addition, two spot samples (AM and PM) were taken during each 12-hour sample collection period. Analysis of the urinary sodium and creatinine was done with a Roche/Hitachi Modular System (Roche Diagnostics, IN, USA). SPSS version 19 was used to analyse the data to make inferences. RESULTS: Thirty Afro-Caribbean subjects participated in this study: 16 females and 14 males. The average age and body mass index (BMI) were 38 ± 17 years and 25.32 ± 5.98 kg/m2, respectively. The greatest correlation of the estimated 24-hour sodium excretion to the measured 24-hour sodium excretion was observed in the 12-hour PM sample (Pearson's correlation, r = 0.786, p < 0.001) followed by the 12-hour AM sample (Pearson's correlation, r = 0.774, p < 0.001). The PM spot sample showed a weaker, but still statistically significant correlation to the 24-hour timed sample (Pearson's correlation, r = 0.404, p < 0.045). The AM spot sample showed a very weak and insignificant correlation (Pearson's correlation, r = 0.05, p = 0.807) to the 24-hour timed sample. Similarly to the whole sample, the gender analysis demonstrated that estimated 24-hour sodium excretion in the female's 12-hour PM sample had the greatest correlation (r = 0.819, p < 0.001) to the measured 24- hour sodium excretion, followed by the 12-hour AM (r = 0.793, p = 0.001) and the PM spot samples (r = 0.741, p = 0.02). The correlation between variables is weaker in males compared to the females. CONCLUSION: Overall, this study shows a clear correlation between the estimated 24-hour sodium excretion from the 12-hour timed PM sample and the measured 24-hour sodium excretion. Such findings support the thought of using other alternatives to determine sodium excretion, in view of replacing the cumbersome 24-hour urinary collection with a smaller timed sample. Nonetheless, a more robust and randomized population sample as well as a method to correct for high creatinine variability is required to further enhance the significance of the obtained results.

OBJETIVO: La excreción del sodio en orina se utiliza como una herramienta de evaluación para la ingesta y manejo de la sal. Si bien resulta engorroso, el método más fiable y fácilmente utilizado en los estudios clínicos y epidemiológicos es la recolección de orina de 24 horas. Este estudio investiga otros medios apropiados de predicción de la excreción del sodio urinario de 24 horas en los afrocaribeños en Barbados, evaluando la correlación real y estimada de la excreción del sodio en orina entre una muestra de orina de 24 horas, 12 horas (AM y PM), y recogidas aleatorias (AM y PM). MÉTODO: Una muestra conveniente de 30 participantes sanos de origen afrocaribeño entre las edades de 21 y 55 años, fue reclutada para el estudio. Las muestras de orina de 24 horas y los datos antropométricos, fueron recogidos tal como se documenta en el procedimiento clínico estándar del estudio. Una muestra de orina de 24 horas fue recogida en forma de muestras de 12 horas AM y PM por separado. Además, se tomaron dos muestras (AM y PM) al azar durante cada periodo de recolección de muestras de 12 horas. El análisis del sodio y la creatinina urinarios fue hecho con un Sistema Modular Roche/Hitachi (Roche Diagnostic, IN, USA). La versión 19 de SPSS fue utilizada para analizar los datos para hacer las inferencias. RESULTADOS: Treinta sujetos afrocaribeños participaron en este estudio: 16 mujeres y 14 hombres. La edad media y el índice de masa corporal (IMC) promedio fueron 38 ± 17 años y 25.32 ± 5.98 kg/m², respectivamente. La mayor correlación de la excreción estimada de sodio de 24 horas con la excreción medida de sodio 24 horas, se observó en la muestra de 12 horas PM (correlación de Pearson, r = 0.786, p < 0.001), seguida por la muestra de 12 horas AM (correlación de Pearson, r = 0.774, p < 0.001). La muestra aleatoria PM mostró una correlación más débil, pero de todos modos estadísticamente significativa con respecto a la muestra cronometrada de 24 horas (correlación de Pearson, r = 0.404, p < 0.045). La muestra aleatoria AM mostró una correlación muy débil y estadísticamente no significativa (correlación de Pearson, r = 0. 05, p = 0.807) con respecto a la muestra cronometrada de 24 horas. De modo similar a la muestra en su totalidad, el análisis de género demostró que la excreción de sodio estimada de 24 horas en la muestra PM de 12 horas de las mujeres, tenía la mayor correlación (r = 0819, p < 0.001) con respecto a la excreción de sodio medida de 24 horas, seguida por las muestras de 12 horas AM (r = 0.793, p = 0.001) y las muestras PM al azar (r = 0.741, p = 0.02). La correlación entre las variables es más débil en los varones en comparación con las hembras. CONCLUSIÓN: En general, este estudio muestra una clara correlación entre la excreción de sodio estimada de 24 horas a partir de la muestra PM cronometrada de 12 horas, y la excreción de sodio medida de 24 horas. Estos hallazgos respaldan la idea de utilizar otras alternativas para determinar la excreción de sodio, teniendo en la mira el reemplazar la engorrosa recogida de orina de 24 horas por una muestra recogida en un tiempo menor. No obstante, una muestra de población más sólida y aleatoria, así como un método para corregir la variabilidad de la creatinina alta, son necesarios para mejorar aún más la importancia de los resultados obtenidos.

Observations of modified three-dimensional instability structure for imploding z-pinch liners that are premagnetized with an axial field.

Novel experimental data are reported that reveal helical instability formation on imploding z-pinch liners that are premagnetized with an axial field. Such instabilities differ dramatically from the mostly azimuthally symmetric instabilities that form on unmagnetized liners. The helical structure persists at nearly constant pitch as the liner implodes. This is surprising since, at the liner surface, the azimuthal drive field presumably dwarfs the axial field for all but the earliest stages of the experiment. These fundamentally 3D results provide a unique and challenging test for 3D-magnetohydrodynamics simulations.

Predicting 24-hour urinary sodium excretion in Afro-Caribbean Barbadians by comparing urine sodium excretion over different durations versus spot collection.

AIM: Urinary sodium excretion is used as an assessment tool for salt intake and salt handling. Even though cumbersome, the most reliable and readily used method in clinical and epidemiological studies is the 24-hour urine collection. This study investigates other appropriate means ofpredicting 24-hour urinary sodium excretion in a sample of Afro-Caribbeans in Barbados by assessing the correlation of actual and estimated urinary sodium excretion between a 24-hour urine collection sample, 12-hour (AM and PM), and spot (AM and PM) urine collections. METHOD: A convenient sample of 30 healthy participants of Afro-Caribbean origin between the ages of 21 and 55 years was recruited for the study. The 24-hour urine samples and anthropometric data were collected as documented in the study's standard clinical procedure. A 24-hour urine sample was collected as two separate 12-hour AM and PM samples. In addition, two spot samples (AM and PM) were taken during each 12-hour sample collection period. Analysis of the urinary sodium and creatinine was done with a Roche/Hitachi Modular System (Roche Diagnostics, IN, USA). SPSS version 19 was used to analyse the data to make inferences. RESULTS: Thirty Afro-Caribbean subjects participated in this study: 16 females and 14 males. The average age and body mass index (BMI) were 38 +/- 17 years and 25.32 +/- 5.98 kg/m2, respectively. The greatest correlation of the estimated 24-hour sodium excretion to the measured 24-hour sodium excretion was observed in the 12-hour PM sample (Pearson's correlation, r = 0.786, p < 0.001) followed by the 12-hour AM sample (Pearson's correlation, r = 0.774, p < 0.001). The PM spot sample showed a weaker, but still statistically significant correlation to the 24-hour timed sample (Pearson 's correlation, r = 0.404, p < 0.045). The AM spot sample showed a very weak and insignificant correlation (Pearson 's correlation, r = 0.05, p = 0.807) to the 24-hour timed sample. Similarly to the whole sample, the gender analysis demonstrated that estimated 24-hour sodium excretion in the female's 12-hour PM sample had the greatest correlation (r = 0.819, p < 0.001) to the measured 24-hour sodium excretion, followed by the 12-hour AM (r = 0.793, p = 0.001) and the PM spot samples (r = 0.741, p = 0.02). The correlation between variables is weaker in males compared to the females. CONCLUSION: Overall, this study shows a clear correlation between the estimated 24-hour sodium excretion from the 12-hour timed PM sample and the measured 24-hour sodium excretion. Such findings support the thought of using other alternatives to determine sodium excretion, in view of replacing the cumbersome 24-hour urinary collection with a smaller timed sample. Nonetheless, a more robust and randomized population sample as well as a method to correct for high creatinine variability is required to further enhance the significance of the obtained results.

Penetrating radiography of imploding and stagnating beryllium liners on the Z accelerator.

The implosions of initially solid beryllium liners (tubes) have been imaged with penetrating radiography through to stagnation. These novel radiographic data reveal a high degree of azimuthal correlation in the evolving magneto-Rayleigh-Taylor structure at times just prior to (and during) stagnation, providing stringent constraints on the simulation tools used by the broader high energy density physics and inertial confinement fusion communities. To emphasize this point, comparisons to 2D and 3D radiation magnetohydrodynamics simulations are also presented. Both agreement and substantial disagreement have been found, depending on how the liner's initial outer surface finish was modeled. The various models tested, and the physical implications of these models are discussed. These comparisons exemplify the importance of the experimental data obtained.

Measurements of magneto-Rayleigh-Taylor instability growth during the implosion of initially solid Al tubes driven by the 20-MA, 100-ns Z facility.

The first controlled experiments measuring the growth of the magneto-Rayleigh-Taylor instability in fast (∼100 ns) Z-pinch plasmas are reported. Sinusoidal perturbations on the surface of an initially solid Al tube (liner) with wavelengths of 25-400 µm were used to seed the instability. Radiographs with 15 µm resolution captured the evolution of the outer liner surface. Comparisons with numerical radiation magnetohydrodynamic simulations show remarkably good agreement down to 50 µm wavelengths.