Classrooms are microenvironments in which children and teenagers may be exposed to fine particulate matter (PM2.5). Iranduba is a rural city in the Amazon region close to many brick kilns and road with high traffic levels. In this study, indoor and outdoor PM2.5 levels were measured in a classroom in Iranduba, and the PM2.5 exposure effects on student’s health were calculated. High indoor PM2.5 concentrations and high indoor-to-outdoor ratio values indicated particle accumulation within the classroom. The high percentage of black carbon (10%) in the dry season revealed the influence of burning processes on PM2.5 composition. Se, S, and Pb had an enrichment factor > 5, indicating that there is an important source for these elements in the city. The positive matrix factorization (PMF) model indicated soil resuspension, burning processes and vehicular emissions as the main PM2.5 sources. The excess risk shows that our classroom occupants are expected to be 30% more likely to develop lung-cancer than a group exposed to a background level of PM2.5. Therefore, it is important to have an effective ventilation system in order to reduce the accumulation of pollutants within the classroom and also to control/decrease the emission of pollutants in the city.

A detailed study of the production of hydrogen and high added-value liquid products from the ethanol dehydrogenation reaction in the presence of sodium hydroxide (10% m m-1) was undertaken. Experiments were carried out in a batch reactor under different reaction conditions (temperature of 240 ºC and autogenous pressure between 45 and 72 bar), with analysis of the products obtained in the gas, liquid and solid fractions. The results showed that hydrogen was the major product formed in the gaseous fraction (maximum of 86.9%), while sodium acetate was the product in the solid fraction. Studies of the reaction mechanisms confirmed formation of the products identified in the gaseous and solid fractions. Mass spectrometry analyses of the liquid fractions revealed the presence of a series of compounds with molecular masses considerably higher than that of ethanol, which could be explained by the favoring of anionic polymerization reactions, under the experimental conditions employed.

This study reports the synthesis and characterization of a Ni/Zn layered double hydroxide salt intercalated with acetate ions and the subsequent replacement of the acetate ions with molybdate ions via an ion exchange reaction, conducted at two different pH values. Regardless of the pH employed during the synthesis, the basal spacing in the Ni/Zn layered double hydroxide salt decreased from 13.08 Å to approximately 9.5 Å, which agreed with intercalation of hydrated molybdate anions. The non-calcined material and the material submitted to heat treatment at 250 °C (basal spacing reduced to 7.35 Å, due to dehydration) were tested as catalyst for the methyl transesterification of soybean oil. Like sodium molybdate in homogeneous media, the solid materials were active catalysts. After reaction at 120 °C for 4 h, the materials afforded high conversions at an alcohol/soybean oil molar ratio of 35:1 and preserved the structure after three consecutive uses. In conclusion, intercalation of molybdate anion into the layered double hydroxide salt proved to be an efficient alternative to support the active species and transform a soluble catalyst into a solid with application in heterogeneous catalysis.

Materials obtained by the immobilization of 12-tungstophosphoric acid (PTA) on silica using the method of impregnation with excess solution in distinct solvents (aqueous HCl, methanol:H2O, and acetonitrile) were evaluated for use as catalysts in the methyl esterification of stearic acid. Optimum conditions were established for the impregnation of 0.5 g (w/w) of PTA on amorphous silica, under stirring at 150 rpm for 24 h, using 20 mL of 0.1 mol L-1 HCl as the solvent. After calcination at 200 ºC, high conversions were obtained under mild reaction conditions, resulting in high turnover numbers. The catalyst was evaluated in ten catalytic cycles of use, where the activity was reduced only slightly, attesting its stability and the possibility to apply it to industrial production of methylesters.

Três óleos essenciais extraídos das folhas, frutos e raízes de Ottonia martiana Miq. (Piperaceae), espécie comum da floresta Atlântica brasileira, e conhecida popularmente por "anestésia", foram analisados por CG-EM e submetidos a um ensaio antibacteriano bioautográfico frente a Staphylococcus aureus (ATCC 25923), Staphylococcus epidermidis (ATCC 12228), Pseudomonas aerogenes (ATCC 27853) e Escherichia coli (ATCC 25922). Setenta e sete compostos foram identificados e submetidos a uma análise comparativa, a qual revelou uma variabilidade no teor dos componentes majoritários desses óleos (espatulenol, óxido de cariofileno, (E)-nerolidol, viridiflorol, beta-cariofileno, delta cadineno e aloaromadendreno). A presença de zonas de inibição de crescimento bacteriano nos bioautogramas analisados (Rfs 0,29 e 0,34) revelou o potencial antibacteriano dos óleos analisados frente às bactérias Gram-positivas testadas e permitiu identificar alguns dos componentes bioativos.

Three essential oils extracted from leaves, fruits and roots of Ottonia martiana Miq. (Piperaceae), common species in Brazilian Rain Forest, known as "anestésia", were analyzed by GC-MS and tested in an antibacterial assay against Staphylococcus aureus (ATCC 25923), Staphylococcus epidermidis (ATCC 12228), Pseudomonas aerogenes (ATCC 27853) and Escherichia coli (ATCC 25922). Seventy-seven compounds were identified and submitted to a comparative analysis, which revealed variability on the amount of principal components of these oils (spathulenol, caryophyllene oxide, (E)-nerolidol, viridiflorol, beta-caryophyllene,deltacadinene and alloaromadendrene). Inhibition zones of bacterial growth in the bioautograms (Rfs 0.29 and 0.34) showed antimicrobial activity of essential oils against tested Gram-positive bacteria and permitted to identify some bioactive components.

Two amides, piperovatine and isopiperlonguminine, were isolated from the roots of Ottonia martiana Miq., a herbaceous shrub commonly used in folk medicine in the treatment of toothache. The crude extract (CE) and isolated compounds were submitted to bioautography and allelopathic assay. The bioautograms allowed the detection of compounds with antibacterial activity and the identification of the bioactive substance piperovatine. The CE and amides exhibited an allelopathic effect on Lactuca sativa (lettuce) seedling growth but did not affect the seeds' germinability.