Bioactive microfluidic paper device for pesticide determination in waters.

This work presents a new optical microfluidic paper biosensor for the detection of organophosphate pesticides and carbamate pesticides. The assay strip is composed of a paper support (1 × 17.6 mm) onto which acetylcholine esterase (AChE) and acetylcholine chloride (AChCl) are deposited, in such a way that there is a small hole between them that ensures that they only come into contact in the reaction zone when they are carried by a solution of the sample by lateral flow to the reaction zone containing bromocresol purple (BCP) as the pH indicator, immobilized by sol-gel.

Modification of African breadfruit (Treculia africana, Decne) kernel starch: Physicochemical, morphological, pasting, and thermal properties.

The need for starch to meet the ever-increasing industrial applications and its inherent problems in the native state have led to researches into unconventional starch sources and starch modifications, respectively. In this study, starch was isolated from African breadfruit kernels and modified to produce acetylated, AC, oxidized, OX, and acid-thinned, AT, starches. The effects of modifications on the native starch, NA, were examined through physicochemical, pasting, morphological and thermal properties.

Varying apparent rate constant: determination of uptake and release of protons during tetramer-dimer dissociation in human hemoglobin A.

The effect of association-dissociation on the sulphydryl reactivity of human hemoglobin A is reported. The reactivity of CysF9(93)beta towards the sulphydryl reagent, 5,5'-dithiobis(2-nitrobenzoate), is higher at lower concentrations of hemoglobin at all pH values. This is because hemoglobin dimers have higher sulphydryl reactivity than tetramers and it is known that the proportion of dimers increases as the hemoglobin concentration decreases.