An artificial neural network (ANN) calibration model was developed to determine aluminum in the presence of iron in soil extracts, using xylenol orange as chromogenic reagent. The spectral data of synthetic mixtures of Al(3+) and Fe(3+) as well as of the soil extracts, were recorded in the range between 410 and 580 nm. Method validation was carried out using 18 soil extracts. The results gave g...

A dynamic combinatorial library of metal-dye complexes was obtained by reacting aqueous solutions of the dyes Methyl Calcein Blue, Arsenazo I, and Xylenol Orange with CuCl(2) and NiCl(2). The mixture gave a characteristic UV-Vis response upon addition of the peptide hormones angiotensin I and angiotensin II. This allowed distinguishing pure samples of peptide hormones from mixtures. The discrim...

High-throughput screening (HTS) involves testing of compound libraries against validated drug targets using quantitative bioassays to identify 'hit' molecules that modulate the activity of target, which forms the starting point of a drug discovery effort. Eicosanoids formed via cyclooxygenase (COX) and lipoxygenase (LOX) pathways are major players in various inflammatory disorders. As the conve...

An experimental investigation of chemical reaction fronts, created by an initial separation of reactants, is reported for a system of two competing reactions. Spatiotemporal patterns are observed experimentally for the competing reaction front and are accounted for quantitatively by a reaction-diffusion model. We use the reaction of xylenol orange with Cr3+ in aqueous solution. Different oligom...

The majority of urinary stones have been observed to grow by circular increments in the clinic and in animal studies. However, the mechanism of stone formation has not yet been elucidated. Marking the stone at specific time-points during the growth of the stone is likely to enable the clarification of the mechanisms behind lithogenesis. The objective of this study was to evaluate the role and e...

A simple and sensitive solid phase spectrophotometric method for the determination of cobalt is proposed based on the reaction between cobalt and xylenol orange (XO). The reaction product is fixed on the anionic exchanger resin sephadex QAE A-25 at pH= 5. The optical absorbance of the anionic gel like resin, packed in a 1.00 mm cell is directly measured at 588.0 nm. The linear range of calibrat...