Optimization of technological procedure for amygdalin isolation from plum seeds (Pruni domesticae semen)

The process of amygdalin extraction from plum seeds was optimized using central composite design (CCD) and multilayer perceptron (MLP). The effect of time, ethanol concentration, solid-to-liquid ratio, and temperature on the amygdalin content in the extracts was estimated using both mathematical models. The MLP 4-3-1 with exponential function in hidden layer and linear function in output layer was used for describing the extraction process. MLP model was more superior compared with CCD model due to better prediction ability. According to MLP model, the suggested optimal conditions are: time of 120 min, 100% (v/v) ethanol, solid-to liquid ratio of 1:25 (m/v) and temperature of 34.4 degrees C. The predicted value of amygdalin content in the dried extract (25.42 g per 100 g) at these conditions was experimentally confirmed (25.30 g per 100 g of dried extract). Amygdalin (>90%) was isolated from the complex extraction mixture and structurally characterized by FT-IR, UV, and MS methods

Discutindo a educação ambiental no cotidiano escolar: desenvolvimento de projetos na escola formação inicial e continuada de professores

A presente pesquisa buscou discutir como a Educação Ambiental (EA) vem sendo trabalhada, no Ensino Fundamental e como os docentes desta escola compreendem e vem inserindo a EA no cotidiano escolar., em uma escola estadual do município de Tangará da Serra/MT, Brasil. Para tanto, realizou-se entrevistas com os professores que fazem parte de um projeto interdisciplinar de EA na escola pesquisada. Verificou-se que o projeto da escola não vem conseguindo alcançar os objetivos propostos por: desconhecimento do mesmo, pelos professores; formação deficiente dos professores, não entendimento da EA como processo de ensino-aprendizagem, falta de recursos didáticos, planejamento inadequado das atividades. A partir dessa constatação, procurou-se debater a impossibilidade de tratar do tema fora do trabalho interdisciplinar, bem como, e principalmente, a importância de um estudo mais aprofundado de EA, vinculando teoria e prática, tanto na formação docente, como em projetos escolares, a fim de fugir do tradicional vínculo “EA e ecologia, lixo e horta”.Facultad de Humanidades y Ciencias de la Educació

Effect of the anodic current density on copper electrodeposition in the hydrogen co-deposition range by the reversing current (RC) regime

In this study, the effect of the anodic current density in the regime of reversing current (RC) on the quantity of evolved hydrogen and morphology of copper deposits was considered. The quantity of evolved hydrogen was quantified by the determination of the average current efficiency for hydrogen evolution reaction, while morphology and internal structures of electrodeposited copper were analyzed using scanning electron (SEM) and optical microscopy techniques, respectively. In all RC experiments, the cathodic current density of 440 mA/cm(2), cathodic pulse of 10 ms and anodic pulse of 5 ms were applied, while the analyzed anodic current densities were: 40, 240, 440 and 640 mA/cm(2). The number, size and shape of holes formed of detached hydrogen bubbles strongly depended on the selected parameters of square waves RC. Due to the decrease of the quantity of evolved hydrogen with the increasing anodic current density, the change of morphology of copper deposits formed around holes from cauliflower-like agglomerates of copper grains to dendrites was observed. Honeycomb-like structures were formed with the anodic current density values up to 440 mA/cm(2). The compactness of the honeycomb-like structures increased with the increase of the anodic current density. The improvement of structural characteristics of the honeycomb-like electrodes was achieved by the application of the RC regime in comparison with both the pulsating current (PC) and constant galvanostatic regimes. It was found that the regime of reversing current is superior in the production of the honeycomb-like electrodes in relation to other current regimes of electrolysis. (C) 2011 Elsevier B.V. All rights reserved

The development of a new inhibition kinetic spectrophotometric method for determination of phenylhydrazine

Anew sensitive kinetic method has been developed for the determination of trace amounts of phenylhydrazine in the range of 1.08×10-7 to 1.08×10-6 g/cm3. The detection limit of this method is 0.008 mg/cm3, based on the 3Sb criterion. Themethod is based on the inhibitory effect of phenylhydrazine on the oxidation of Victoria Blue 4-R by KBrO3. The reaction was monitored spectrophotometrically at 596.3 nm. The method development includes the optimization of the reagent concentration and temperature. The kinetic parameters of the reaction are reported and a rate equation is suggested. The effects of certain foreign ions upon the reaction rate were determined for the assessment of the selectivity of the method. The new developedmethod was found to have fairly good selectivity, sensitivity, simplicity and rapidity

Insulin-induced lipid binding to hemoglobin

Under hypoglycemic conditions, concomitant hyperinsulinism causes an apparent modification of hemoglobin (Hb) which is manifested by its a aggregation (Niketic et al.. Clin. Chim. Acia 197 (1991) 47). In the present work the causes and mechanisms underlying this Hb modification were Studied. Hemoglobin isolated from normal erythrocytes incubated with insulin was analyzed by applying P-31-spectrometry and lipid extraction and analysis. To study the dynamics of the plasma membrane during hperinsulinisra a fluorescent lipid-analog was applied. In the presence of insulin phosphatidylserine (PS). phosphatidylethanolamine (PE) and cholesterol were found to bind to Hb. Lipid binding resulted in Hb aggregation, a condition that can be reproduced when phospholipids arc incubated with Hb in vitro. Using a fluorescent lipid-analog, it was also shown that exposing crythrocytes to supraphysiological concentrations of insulin in vitro resulted in the internalization of lipids. The results presented in this work, may have relevance to cases of diabetes mellitus and hypoglycemia

Morphological and crystallographic characteristics of lead powder obtained by electrodeposition from an environmentally friendly electrolyte

Lead powder obtained by potentiostatic electrodeposition from alkaline electrolyte, based on hydroxide ions, was investigated. The shape of lead crystals strongly depends on overpotentials of electrodeposition. The regular crystals are formed in the ohmic control. The shape of dendrites formed in the control of diffusion has a function of overpotentials of the electrodeposition. Increasing overpotential leads to branching of dendrites from primary type to those with developed tertiary branches. Formation of the very branchy dendrites of the strong (111) preferred orientation is explained on the basis of the affiliation of this electrolyte to the group of the complex Pb electrolytes

Structural and electrical properties of sintered Fe2O3/TiO2 nanopowder mixtures

Starting nanopowders of TiO2 (anatase 99.7%) and α-Fe2O3 (hematite) were mixed in the weight ratios 60:40 and 40:60. Green samples were sintered in the temperature range 750–1250 °C in air. Structural, morphological and electrical studies were carried out using XRD, SEM and EDS analysis, Hall measurements and electrical conductivity measurements. The aim was analyzing the influence of the starting nanopowder structure on the resulting sample composition, density, grain size and electrical resistivity in view of tailoring properties for developing different applications such as anodes for photoelectrochemical cells, photocatalysts and gas sensors. Compared to pure anatase samples, the presence of hematite lowered the temperature of completion of the anatase to rutile phase transformation to 850 °C. Formation of pseudobrookite was also noted at this temperature. Higher sintering temperatures lead to increased sample density, changes in grain size (grain growth and inhomogenous microstructure) and decreased electric resistivity