Modelling chloride-discharge relationships in Krishna river basin.

Chloride discharge relationships at several monitoring stations on the River Krishna in South India are investigated, both qualitatively and quantitatively, to identify probable source contributions. The chloride behaviour along the waterway is studied in detail to assess the source contributions at various monitoring stations falling within the study area. Seasonal variations in the intensity of rainfall cause wide variations in the quality of the River Krishna. As there is strong seasonal dependence between the flow in the river and chlorides, seasonal models are developed for prediction of concentrations and loads. Linear regression analysis is carried out to determine the model parameters. The predicted concentrations and loads are in agreement with the observed values within the uncertainty of data. As the area is characterized by distinct dry and wet seasons (based on rainfall distribution over the year), mass balances are used to differentiate between point and non-point source contributions to the river. In large river basins, monitoring all individual sources is difficult and/or impossible and expensive; hence the presented approach based on receiving water quality and flow serves as an alternative for modeling chlorides in the river basin. Results of the study can be used to emphasise water pollution control strategies.

Dimethyl suberimidate as an effective crosslinker for antibody-enzyme conjugation.

Dimethyl suberimidate (DMS), a bifunctional reagent was used for the first time to crosslink the alpha-feto protein monoclonal antibodies (AFPMAb) to horse radish peroxidase (HRP). Three batches of conjugates were prepared, purified by Sephadex gel chromatography and evaluated for their immunological reactivity. The Rz values obtained for AFPMAb-HRP conjugate were 0.39 to 1.36. Under optimised conditions the ELISA results showed the optical density of 1.9. The iso-electric focusing for the conjugate revealed different degrees of crosslinking between antibodies and HRP. It was evident that isoperoxidase-C was involved in the crosslinking process. From the dot ELISA, as low as 25 pg of AFP in the test samples could be detected with AFPMab-HRP conjugate. The conjugate prepared by DMS was stable at 0 degrees C for more than 10 months.