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The removal of sulfur and nitrogen compounds from oil derivatives is fundamental to fulfill the new environmental laws. Traditionally, this removal is carried out through hydrotreatment processes; however, regarding environmental and economic issues, the refining oil industry has been studying adsorption processes to reduce sulfur and nitrogen compound levels in diesel streams. The aim of this work was to study the influence of chemical composition and acid–base properties of commercial alumina, silica, and silica–alumina samples on the removal of sulfur and nitrogen compounds from diesel streams. It was observed that acid and textural properties and surface composition influence the adsorptive capacity of the samples. The results indicated that the adsorbents tested were more efficient for the removal of nitrogen compounds. Kinetic and adsorption experiments using model fuel containing sulfur and nitrogen compounds were also carried out. Freundlich and Sips models described the adsorption of 4,6-dimethyldibenzothiophene and quinoline on silica–alumina, respectively.

The purpose of this study was to establish a possible correlation between systemic hypermobility and temporomandibular hypermobility during pregnancy. One hundred (100) healthy pregnant women were evaluated: 7% in the first trimester (1T), 38% in the second trimester (2T), and 55% in the third trimester (3T) of gestation. In the series, the authors analyzed systemic joint hypermobility (SJH), range of mandibular movement (MMR), head and shoulder posture, head lateralization, and the presence of noise, pain, and parafunction in the temporomandibular joint. They observed that pain is present to a mild degree mostly in the head and ears of all pregnant women who presented with pain. Most of the subjects had some type of parafunction, but only 42.8% had noises. Mild SJH was seen in 50% of the 2T and 3T subjects, and in 28.5% of 1T subjects. Mild mandibular hypermobility was found for jaw opening (46%) and lateralization to the right (44%) or to the left (46%). Most of the subjects had hypomobility for jaw protrusion and retraction. The subjects had head protrusion and anterior posture as a result of the change in their center of gravity brought about by pregnancy. The authors found no association between systemic joint hypermobility (SJH) and temporomandibular hypermobility, although hormonal changes and complex factors during pregnancy may represent a risk factor for both types of mobility change.

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