Ion-exchange method in the collection of nitrate from freshwater ecosystems for nitrogen and oxygen isotope analysis: a review.

Nitrate (NO3(-)) contamination of freshwater is considered one of the most prevalent global environmental problems. Dual stable isotopic compositions (δ(15)N and δ(18)O) of NO3(-) can provide helpful information and have been well documented as being a powerful tool to track the source of NO3(-) in freshwater ecosystems. The ion-exchange method is a reliable and precise technique for measuring the δ(15)N and δ(18)O of NO3(-) and has been widely employed to collect NO3(-) from freshwater ecosystems. This review summarizes and presents the principles, affecting factors and corresponding significant improvements of the ion-exchange method. Finally, potential improvements and perspectives for the applicability of this method are also discussed, as are suggestions for further research and development drawn from the overall conclusions.

[Comparison between therapeutic effects of acupuncture and intravenous injection of amiodarone in the treatment of paroxymal atrial fibrillation and atrial flutter].

OBJECTIVE: To probe the feasibility of acupuncture in conversion of paroxymal atrial fibrillation and atrial flutter. METHODS: Eighty cases of atrial fibrillation and atrial flutter were randomly divided into 2 groups, a treatment group and a control group, 40 cases in each group. The treatment group were treated with acupuncture at Neiguan (PC 6), Shenmen (HT 7), Danzhong (CV 17) and others, and the control group with intravenous injection of amiodarone. The cardiac rhythms and side effects were observed in the two groups. RESULTS: The total effective rate of 85.0% in the treatment group was better than 67.5% in the control group (P < 0.01). The average conversion time was (39.6 +/- 13.7) min in the treatment group and (50.1 +/- 14.8) min in the control group with a significant difference between the two groups (P < 0.01). No adverse effect was found in the treatment group. CONCLUSION: Acupuncture is a safe and effective therapy for conversion of paroxymal atrial fibrillation and atrial flutter.