Dissolved Carbon Dioxide Sensing Platform for Freshwater and Saline Water Applications: Characterization and Validation in Aquaculture Environments.

A sensing configuration for the real-time monitoring, detection, and quantification of dissolved carbon dioxide (dCO2) was developed for aquaculture and other applications in freshwater and saline water. A chemical sensing membrane, based on a colorimetric indicator, is combined with multimode optical fiber and a dual wavelength light-emitting diode (LED) to measure the dCO2-induced absorbance changes in a self-referenced ratiometric scheme. The detection and processing were achieved with an embeded solution having a mini spectrometer and microcontroller. For optrode calibration, chemical standard solutions using sodium carbonate in acid media were used. Preliminary results in a laboratory environment showed sensitivity for small added amounts of CO2 (0.25 mg·L-1). Accuracy and response time were not affected by the type of solution, while precision was affected by salinity. Calibration in freshwater showed a limit of detection (LOD) and a limit of quantification (LOQ) of 1.23 and 1.87 mg·L-1, respectively. Results in saline water (2.5%) showed a LOD and LOQ of 1.05 and 1.16 mg·L-1, respectively. Generally, performance was improved when moving from fresh to saline water. Studies on the dynamics of dissolved CO2 in a recirculating shallow raceway system (SRS+RAS) prototype showed higher precision than the tested commercial sensor. The new sensor is a compact and robust device, and unlike other sensors used in aquaculture, stirring is not required for correct and fast detection. Tests performed showed that this new sensor has a fast accurate detection as well as a strong potential for assessing dCO2 dynamics in aquaculture applications.

Observacoes sobre o emprego da rifampicina em hansenianos aparentemente sulfono-resistentes / Observations on the use of rifampicin in apparently sulfone-resistant hanseniasis patients

Os autores relatam os resultados obtidos com a rifampicina no tratamento de 10 pacientes de hanseníase virchoviana, clinicamente resistentes à sulfonoterapia. São apresentadas as observações clínicas, os exames baciloscópicos, histopatológicos, de sangue, urina e as provas de função hepática. Os resultados siginificativos levam os autores a confirmar a ação do medicamento e sua indicação como de escolha nos casos de hanseníase sulfono-resistente.