Effect of Spacer Length and Solvent on the Concentration-Driven Aggregation of Cationic Hydrogen-Bonding Donor Polythiophenes.

Aggregation of cationic isothiouronium polythiophenes with alkoxy-spacers of different lengths at the 3-position of the thiophene ring was studied in solvents of different polarities. Hydrogen-bonding capacity was assessed by steady-state absorption and fluorescence spectroscopy, whereas the aggregation in aqueous solutions was studied by electron paramagnetic resonance spectroscopy, using paramagnetic probes of different polarities. The two polymers displayed similar features in respect to conformation, effect of cosolvents on aggregation, unstructured absorption-fluorescence spectra, Stokes shifts when aggregated, solvatochromic effect, and self-quenching concentration. However, these polymers also showed different specific interactions with water, Stokes shifts in water, effect of the solvent on the extent of dominant state of the S1 level, and also different inner cavities and hydrophobic-hydrophilic surface area in aqueous solution aggregates. Water maximized the difference between the polymers concerning the effect of specific increases in concentration, whereas the presence of 1,4-dioxane generated almost identical effects on both polymers.

The effect of 2,4-dinitrophenol on the metabolic rate of bobwhite quail.

Bobwhite quail were exposed to 2,4-dinitrophenol (DNP) in a respirometer designed to continuously monitor exchange of O2 and CO2, from which metabolic rates (MR) were estimated. After 14-16 days of acclimation to the system (temperature 22 degrees C, light cycle 8L:14D), hens received feed amended with 0, 625, or 1250 ppm DNP ad libitum for 8 days, followed by 2-5 days of feed containing no DNP. The 625 ppm treatment produced dark-period MR 31-41% higher than corresponding control values, and light-period MR 23-32% higher than controls. The 1250 ppm treatment produced dark-period MR 48-77% higher than control values, and light-period MR 41-67% higher than controls. Over the 8 days of testing, the 625 ppm treatment hens expended 32% more energy than the control hens. Hens consuming 1250 ppm feed expended 60% more energy than control hens and lost most of their body fat. In general, the risk of being unable to meet energy demands for survival or reproduction would probably be substantially increased by the observed elevation in MR.

[Strategy for monitoring and implementing methods for correcting child growth and development in rural areas of Sonora. Mexico]. / Estrategia del monitoreo e implementación de métodos correctivos sobre el crecimiento y desarrollo del niño en zonas rurales en Sonora. México.

An appropriate health technology to facilitate child growth and development in a rural area is presented and documented. Because mother's adequate behavior related to child's care does not produce immediate behavioral or physical changes it is necessary to create a long term social system of consequences. This was achieved joining a longitudinal measurement system with a program to train mothers to identify and deal with health and development issues. During four years, data were collected on weight-length development and morbidity twice a year and simultaneously skills were taught to diagnose treatment and prevent growth and development problems. After the third session child development and anthropometry data became the base of a system to assess maternal behavior, providing consequences for links in the behavior chains associated with child care. This system made organization and participation of the community in primary health care programs more likely, which implied a better score in each child growth and development chart.