Abstract: Stable isotopes of oxygen (δ18O) and hydrogen (δD) in water were used as important indicators to research the hydrologic cycle or processes. To study the hydrologic cycle characteristics of the Jinxiuchuan basin, the isotope labelling and the industrial salt tracing method were used in this research. Sixty-seven samples of different water bodies were collected at different sampling sites from July 2011 to July 2012. The stable hydrogen and oxygen isotopes in water samples were measured by using Liquid Water Isotope Analyzer (LWIA-24d) to study the conversion relationship among precipitation, river water, soil water, and groundwater of the Jinxiuchuan basin in Jinan. The results show that δD and δ18O varied from 35.6 ‰ to 128.3 ‰ and from 5.3 ‰ to 17.5‰, respectively. A meteoric water line of δD = 7.16δ18O + 4.35‰, which was in accordance with the global meteoric water line and the meteoric water line of China, was established in the Jinxiuchuan basin. The deuterium excess values vary with time and space, ranging from 5.1 to 22.3‰, and increase gradually from the southeast to the northwest. In addition, the exchange of different water bodies was determined preliminarily, the rates of precipitation transforming into river water, soil water, and groundwater are 43.76%, 21.91% and 6.84%, and the remaining is 27.49% returned to the atmosphere. The results indicated the hydrologic cycle characteristics in the Jinxiuchuan basin. It may provide the references for precipitation isotopes research in semi-humid regions.

Resumen: Se emplearon isótopos estables de oxígeno (δ18O) e hidrógeno (δD) en agua como indicadores importantes para comprender el ciclo hidrológico o sus procesos. Para comprender las características del ciclo hidrológico en la cuenca de Jinxiuchuan, en este estudio se empleó el método de marcaje isotópico y la técnica de trazabilidad de sal industrial. Se tomaron 67 muestras de distintos cuerpos de agua en diferentes sitios de muestreo de julio de 2011 a julio de 2012. Se midieron los isótopos estables de hidrógeno y oxígeno en las muestras de agua mediante el uso del Analizador de Isótopos en Agua Líquida (LWIA-24-d) para examinar el vínculo entre la precipitación, el agua de río, el agua de suelo y el agua subterránea de la cuenca de Jinxiuchuan, en Jinan. Los resultados muestran que δD y δ18O variaron de 35.6 ‰ a 128.3 ‰ y de 5.3 ‰ a 17.5 ‰, respectivamente. La línea de agua meteórica se estableció en la cuenca de Jinxiuchuan, por ejemplo δD=7.16δ18O+4.35 ‰, lo cual concordó con la línea de agua meteórica global y la línea de agua meteórica de China. Los valores de exceso de deuterio varían en el tiempo y el espacio, entre 5.1 y 22 ‰, e incrementan gradualmente del sudeste al noroeste. Asimismo, se determinó preliminarmente el intercambio de distintos cuerpos de agua; los índices de precipitación que se transformó en agua de río, agua de suelo y agua subterránea son de 43.76%, 21.91% y 6.84%, y el restante 27.49% regresó a la atmósfera. Los resultados indicaron las características del ciclo hidrológico en la cuenca de Jinxiuchuan, las cuales tienen valor de referencia para la investigación de isótopos en la precipitación en regiones semihúmedas.

OBJECTIVES: This study investigated whether the serum matrix metalloproteinase-9 level is an independent predictor of recurrence after catheter ablation for persistent atrial fibrillation. METHODS: Fifty-eight consecutive patients with persistent atrial fibrillation were enrolled and underwent catheter ablation. The serum matrix metalloproteinase-9 level was detected before ablation and its relationship with recurrent arrhythmia was analyzed at the end of the follow-up. RESULTS: After a mean follow-up of 12.1±7.2 months, 21 (36.2%) patients had a recurrence of their arrhythmia after catheter ablation. At baseline, the matrix metalloproteinase-9 level was higher in the patients with recurrence than in the non-recurrent group (305.77±88.90 vs 234.41±93.36 ng/ml, respectively, p=0.006). A multivariate analysis showed that the matrix metalloproteinase-9 level was an independent predictor of arrhythmia recurrence, as was a history of atrial fibrillation and the diameter of the left atrium. CONCLUSION: The serum matrix metalloproteinase-9 level is an independent predictor of recurrent arrhythmia after catheter ablation in patients with persistent atrial fibrillation.