ABSTRACT
Defining and visualizing the three-dimensional (3D) structures of pharmaceuticals provides a new and important tool to elucidate the phenomenal behavior and underlying mechanisms of drug delivery systems. The mechanism of drug release from complex structured dosage forms, such as bilayer osmotic pump tablets, has not been investigated widely for most solid 3D structures. In this study, bilayer osmotic pump tablets undergoing dissolution, as well as after dissolution in a desiccated solid state were examined, and visualized by synchrotron radiation micro-computed tomography (SR-μCT). In situ formed 3D structures at different in vitro drug release states were characterized comprehensively. A distinct movement pattern of NaCl crystals from the push layer to the drug layer was observed, beneath the semi-permeable coating in the desiccated tablet samples. The 3D structures at different dissolution time revealed that the pushing upsurge in the bilayer osmotic pump tablet was directed via peripheral "roadways". Typically, different regions of the osmotic front, infiltration region, and dormant region were classified in the push layer during the dissolution of drug from tablet samples. According to the observed 3D microstructures, a "subterranean river model" for the drug release mechanism has been defined to explain the drug release mechanism.
ABSTRACT
ABSTRACT: Increasing the agricultural machinery visibility makes public roadways traffic safer by reducing the number of accidents and their severity. The study aimed to verify the compliance of new agricultural tractors with Brazilian law, given by, CONTRAN Resolution N° 454, NR12 and NR31, regarding the presence of lighting and signaling elements for traffic. The study was carried out in agricultural machinery dealers of seven brands, corresponding to 50 different models of new wheeled agricultural tractors. The items that was not present in total tractors sample are the rear position lamp, the reverse light and the rear retro-reflector. In addition, only one of the seven brands studied showed complete compliance with evaluated elements. Although, the Brazilian legislation specify the presence of lighting and signaling items for agricultural tractors traffic, there is not fully comply on tractors models analyzed and the Brazilian law are not homogeneously met by the agricultural tractor manufacturers in the verified sample, what can be leading to tractors traffic accident occurrences.
RESUMO: Aumentar a visibilidade das máquinas agrícolas torna o tráfego em vias públicas mais seguro, reduzindo o número de acidentes e sua gravidade. O estudo teve como objetivo verificar a conformidade dos tratores agrícolas com a legislação brasileira, dada pela Resolução CONTRAN N°454, NR12 e NR31, quanto a presençados elementos de iluminação e sinalização para o tráfego. O estudo foi desenvolvido em concessionárias de máquinas agrícolas de sete marcas, correspondendo a 50 modelos distintos de tratores agrícolas de pneus, novos. Os itens que não estavam presentes na totalidade de tratores avaliados foram a luz de posição traseira, a luz de marcha à ré e as faixas retrorrefletivas. Apenas uma das sete marcas estudas apresentou total conformidade dos itens avaliados. Apesar da legislação brasileira especificar a presença dos elementos de iluminação e sinalização para o tráfego de tratores em vias públicas, não há total conformidade nos modelos avaliados e a legislação não é cumprida de forma homogênea pelos fabricantes, o que pode estar relacionado à ocorrência de acidentes com tratores agrícolas no tráfego.