Celtis iguanaea (Jacq.) Sargent (Cannabaceae) é uma das espécies nativas do cerrado brasileiro, sendo amplamente utilizada na medicina popular para o tratamento de dispepsia. O objetivo do presente trabalho foi avaliar o efeito gastroprotetor do extrato hexânico das folhas de Celtis iguanaea (Jacq.) Sargent (EH) em modelos de secreção e de lesões gástricas. A atividade antisecretória do extrato hexânico das folhas de Celtis iguanaea (EH) foi avaliada no modelo de mucosa isolada de Rana catesbeiana e pelo modelo de ligadura pilórica em camundongos. A avaliação da atividade anti-ulcerogênica do EH foi determinada no modelo de úlceras gástricas induzidas por indometacina e ligadura pilórica. Quando a mucosa de Rana catesbeiana isolada foi incubada com o EH, a secreção de H+ foi reduzida em comparação com o valor basal (15,58 ± 1,99 µEq H+/g/15 min). O tratamento com o EH reduziu o índice de lesões na úlcera induzida por indometacina e ligadura pilórica. O EH também reduziu o volume de secreção, a acidez total, e aumentou o pH gástrico. A administração intraduodenal reduziu a secreção gástrica produzida por betanecol ou histamina. A eficácia anti-ulcerogênica e antisecretória do EH neste estudo, sugere um mecanismo anticolinérgico e antihistaminérgico ou interrupção de eventos intracelulares que estão ligados à secreção ácida.

The Celtis iguanaea (Jacq.) Sargent (Cannabaceae) is one of the native species of the Cerrado region of Brazil widely used in folk medicine to treat dyspepsia. The objective of the present study was to evaluate the gastroprotective effect of the Celtis iguanaea (Jacq.) Sargent (HE) hexane leaf extract in the lesion and gastric secretion models.Antiulcerogenic activity of the Celtis iguanaea (HE) hexane leaf extract was observed with the experimental models, such as indomethacin and pyloric ligation-induced gastric ulcers. In order to evaluate the antisecretory activity of this extract, isolated Rana catesbeiana mucosa and pyloric ligation in mice were used. The HE treatment reduced the lesion index of indomethacin and pyloric ligation-induced ulcer. This extract also reduced the gastric acid secretion and total acidity (increasing the gastric pH) in mice. The secretion of H+ was reduced in the basal values (15.58 ± 1.99 µEq H+/g/15 min) when isolated Rana catesbeiana mucosa was incubated with HE. Intraduodenal administration of HE reduced the gastric secretion produced by bethanecol or histamine. The antiulcerogenic and antisecretory efficacy of HE in this study suggest anticholinergic and antihistaminergic mechanism or interruption of intracellular events that are linked to acid secretion.

Even in at very low concentrations, heavy metals in industrial waste constitute environmental and health risks. The U.S. Department of Health and Human Services has recognized as chromium compounds and defined carcinogens the level acceptable in drinking water as being only 0.05 ppm. The objective of this work was the electrochemical reduction of hexavalent chromium Cr (VI) to Cr (III) ions in a dilute synthetic solution of K2Cr2O7 and Na2SO4 (0.05N). A plug-flow reactor with an RVG 4000 graphite felt (Le Carbone Lorraine, France) electrode was used for this work. Its morphological characteristics such as specific variables surface, porosity, average fibre diameter and permeability were determined. The influencing process selectivity such as initial concentration of Cr (VI), solution pH, current intensity and conversion yield are considered. The fractional conversion achieved in the plug-flow reactor in the present work, was about 90%.

The objective of the present work is to study the variation of the electrode distribution potential under electrical conductivity variation of graphite felt RVG 4000 ( Le Carbone Lorraine) when submitted to a mechanical compression. Experimental and theoretical studies show that this electrical conductivity variation can changes the electrode potential distribution E(x) working under limiting current conditions. This may occur when graphite felt is confined in an electrochemical reactor compartment or simply when it is submitted to a force performed by an electrolyte percolation in a turbulent flow. This investigation can contribute to the improvement of electrochemical cells that may use this material as an electrode. Finally, one modification is suggested in the equation that gives the electrode potential distribution E(x) - E(0). In this case the parameter L (thickness in metal porous electrodes) is substituted for Lf = Li (1-j), where j corresponds to the reduction factor of the initial thickness Li.