Bioaccessibility of p,p'-DDT and p,p'-DDE in tropical soil ecosystems: a model based on pollutant speciation coefficients and the desorption free energy of adsorbed speciation forms.

The bioaccessibility of organic pollutants in the environment depends on the nature and speciation of the contaminants and is determined using in vitro methods that simulate gastro-intestinal digestion. The objectives of the present study were to study the bioaccessibility coefficients of p,p'-DDT and p,p'-DDE in tropical soils based on the physico-chemical properties of the contaminant. The behavior of organic contaminants in soil ecosystems is characterized by their speciation and persistence, both of which depend on the extent to which the contaminant adsorbs to particulates in the soil matrix, as revealed in the characteristic persistence curve of the contaminant.

Antioxidant extracts from Dicerocaryum senecioides as active ingredients in semi-permanents and hair conditioners.

Background: Different hair types respond differently to cosmetic treatments; hence, many options ought to be availed to the consumer. The purpose of this study was to evaluate the use of antioxidant extract from Dicerocaryum senecioides as active alternatives in hair semi-permanent waving and hair conditioning.

Methods: The antioxidant phytochemicals were first identified and isolated by thin-layer chromatography (TLC) and spraying with revealing agents.

Persistence and fate of chlortetracycline in the aquatic environment under sub-tropical conditions: generation and dissipation of metabolites.

The persistence of chlortetracycline in the aquatic environment, including the generation and dissipation of its metabolites, were investigated over a period of 90 days using microcosm experiments, with a view to establishing the metabolites generated and their persistence under conditions closely resembling the actual aquatic environment in terms of chemical and microbial composition. The concentrations of chlortetracycline and its metabolites were monitored in the water phase as well as the sediment phase. Data are presented showing that the degradation of chlortetracycline in each phase conforms to a triphasic linear rate law, confirming the existence of three speciation forms in each phase, attributed to one free dissolved form, and two colloidal particle adsorbed forms.

Hair Growth Promoting Effect of Phytochemicals.

Phytochemicals from were studied for hair rejuvenation activity using BalB/c mice. Solvent extractions and thin layer chromatography (TLC) were used to extract and isolate the phytochemicals respectively. Phytochemicals were identified by spraying with target-specific revealing reagents.

Speciation and persistence of doxycycline in the aquatic environment: Characterization in terms of steady state kinetics.

The aim of the present work was to establish the kinetics for the degradation of doxycycline in the aquatic environment with a view to arriving at a kinetic model that can be used to predict the persistence of antibiotic with confidence. The degradation of doxycycline in both water and sediment phases of aquatic microcosm experiments, as well as in distilled water control experiments, was studied over a period of 90 days. An initial 21% loss due to adsorption by the sediment was observed in the microcosm experiment soon after charging.

Anaesthetic effects of Adenia gummifera distillates on Apis mellifera (Honeybee).

The anaesthetic activities of steam distillates of Adenia gummifera stem on Apis mellifera were evaluated by a diffusion method. Live, direct and fractional (61-80 degrees C fraction) distillates had greater anaesthetic effect while vacuum distillates were mild. The anaesthetic activity significantly increased with concentration up to 6% (v/v), and then it levelled off, while excessive exposure was lethal.