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.

[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.