Yearly impact of submonthly rain fluctuations on the Indian Ocean salinity

We investigate the impact of submonthly rain fluctuations on the daily-to-interannual variations of the salinity in the tropical Indian Ocean. A three-year record of daily observed precipitation and wind are used to force an Indian Ocean model in two experiments that differ only by their rain forcing, which is either daily-(Exp_day) or monthly- (Exp_month) averaged. Results show that submonthly precipitations significantly impact the Surface Layer Salinity (SLS) in the northern and eastern Bay of Bengal during the wet season from May to November. In September when the Bay reaches its SLS minimum, the Andaman Sea is saltier by as much as 1.3 psu for Exp_day. The frequency shift between the submonthly rain forcing and the yearly salinity response is due to accumulation in time of nonlinear mechanisms: sudden rain deficits increase the SLS by entraining salty waters from below, whereas rain excesses are inefficient to decrease the salinity of the thick surface layer

Quantification of zidovudine and its monophosphate in cell extracts by on-line solid-phase extraction coupled to liquid chromatography

International audienceA simple and rapid analytical method for the simultaneous quantification of zidovudine (AZT) and its monophosphate (AZTMP) in cell extracts has been developed using high-performance liquid chromatography (HPLC) with on-line solid-phase extraction and 2-aminoethyl-3′-azido-2′,3′-dideoxythymidin-5′-yl phosphodiester sodium salt as internal standard (IS). The cell extract samples were directly injected on a short reversed-phase precolumn using an aqueous buffer containing an ion-pairing reagent as a mobile phase. Under these conditions, the analytes were retained on the precolumn whereas the proteins were discarded. The analytes were then transferred onto the analytical column by increasing the strength of the eluent. The calibration curve was linear over a concentration range of 0.5–100 μg/ml. Inter- and intra-day accuracy and precision results satisfied the accepted criteria for bioanalytical validation. This method was used to study the decomposition pathway of a model pronucleotide in an in vitro approach

Aptamer-Modified Micellar Electrokinetic Chromatography for the Enantioseparation of Nucleotides.

International audienc

Separation of diastereoisomers of Ara-C phosphotriesteres using solid phase extraction and HPLC for the study of their decomposition kinetic in cell extracts.

International audienc