Proteinograma do soro lácteo de ovelhas da raça santa inês em diferentes fases de lactação

This study aimed to evaluate the influence of lactation phases on the proteinogram of whey protein in Santa Inês ewes. Ewes were accompanied in a semi-intensive system using the same sanitary and nutritional management evaluated at 15, 30, 60 and 90 days postpartum (end of weaning and lactation). Clinical examination of the mammary gland was carried out through and bacteriological culture. The screening of the material resulted in 44 milk samples of healthy glands concurrent negative by CMT and bacteriological culture exam. For obtaining the whey protein renin solution was used. The whey was fractionated into aliquots and kept in the -80C freezer to later separation of protein fractions. For determination of total protein of whey protein was employed the biuret, observing the linearity of the test. Separation of protein fractions was performed, using polyacrylamide gel containing sodium dodecyl sulfate (SDS-PAGE). Eigth protein were observed including lactoferrin, serum albumin, IgA, IgG (heavy chain IgG (IgG CP), light chain IgG (IgG CL), ß-lactoglobulin, a-lactalbumin and proteins identified as PM 15000 and PM 29000. No significant difference was observed at different stages of lactation in the following protein: IgA (P>0.3895), lactoferrin (P>0.1611), PM 29000 (P>0.4879), α-lactalbumin (P>0.0799) and PM15000 (P>0.4494). In total protein (P<0.0022), albumin protein (P<0.0377) and IgG (P<0.0354) it was observed a significant variation in the first moments of observations, in the ß-lactoglobulin protein (P<0.0005) there was significant variation with reduction of 15 to 30 days postpartum with progressive elevation until the last stage of lactation (90 days postpartum). The SDS-PAGE technique allowed the quantification of eigth whey proteins in health ewes. The protein fractions identified reflect the profile of whey to ovine species, with influence of stages of lactation in albumin, IgG and ß-lactoglobulin.

Solid-phase extraction of metal ions from fuel ethanol with a nanostructured adsorbent

This work describes the synthesis and characterization of a new octakis[3-(2,2'-dipyridylamine)propyl]octasilsesquioxane (T8-Pr-DPA), and a study of the metal ion preconcentration in fuel ethanol. Batch and column experiments were conducted to investigate for the removal of heavy metal ions from fuel ethanol. The results showed that the Langmuir allowed to describe the sorption equilibrium data of the metal ions on T8-Pr-DPA in a satisfactory way. The following maximum adsorption capacities (in mmolg-1) were determined: 3.62 for Fe (III), 3.32 for Cr (III), 2.15 for Cu (II), 1.80 for Co (II), 1.62 for Pb (II), 1.32 for Ni (II) and 0.88 for Zn (II). The thermodynamic parameters for the adsorption process such as free energy of adsorption (δG), enthalpy of adsorption (δH) and entropy of adsorption (δS) were calculated. Thermodynamic parameters showed that the system has favorable enthalpic, Gibbs free energy, and entropic values. The sorption-desorption of the metal ions has made possible the development of a preconcentration and determination method of metal ions at trace level in fuel ethanol. The method of quantitative analysis for Fe, Cu, Ni and Zn in fuel ethanol by Flame AAS was validated. Several parameters have been taken into account and evaluated for the validation of method, namely: linearity, limit of detection, limit of quantification, and the relative standard deviation and accuracy. The accuracy of the method was assessed by testing analyte recovery in the fuel ethanol samples. © 2013 Elsevier B.V.

UV filters in water samples: Experimental design on the SPE optimization followed by GC-MS/MS analysis

Esse estudo descreve o desenvolvimento e otimização de um método de extração em fase solida (SPE) para análise dos filtros ultravioletas (UV): benzofenona-3 (BP-3), etilhexil salicilato (ES), etilhexil metoxinamato (EHMC) e octocrileno (OC) em matrizes ambientais. Um planejamento fatorial fracionário (PFF) 25-1 foi empregado na avaliação das variáveis significativas do método de extração. As condições experimentais otimizadas da avaliação estatística foram: capacidade do cartucho de 500 mL, eluente acetato de etila, metanol como solvente de lavagem (10% em água, v/v) and volume do eluente de 3 × 2 mL e pH 3. Os parâmetros analíticos avaliados foram satisfatõrios, apresentando linearidade de 100 a 4000 ng L -1, recuperaç ões para os quatro níveis de fortificação (Limite de Quantificação do Método, 200, 1000 e 2000 ng L-1) entre 62 e 107% com desvio padrão relativo menor que 14%. Os limites de quantificação foram encontrados na faixa de ng L-1, variando entre 10 e 100 ng L-1. O método proposto foi aplicado para a determinação dos quatro filtros UV em amostras de águas naturais. This study describes the development and optimization of a solid-phase extraction (SPE) method for analysis of ultraviolet (UV) filters, benzophenone-3 (BP-3), ethylhexyl methoxycinnamate (EHMC), ethylhexyl salicylate (ES) and octocrylene (OC), in environmental matrices. A 25-1 fractional factorial design (FFD) was used to evaluate the significant variables for the extraction method. The optimized experimental conditions determined from the statistical evaluation were: breakthrough volume of 500 mL, eluent of ethyl acetate, wash solvent of methanol (10% in water, v/v), eluent volume of 3 × 2 mL and pH 3. The evaluated analytical parameters were satisfactory for the analytes and showed linearity between 100 and 4000 ng L-1, recoveries for four fortification levels (Method Quantification Limit, 200, 1000 and 2000 ng L-1) were between 62 and 107% with relative standard deviations less than 14%. Limits of quantification were in the ng L-1 range and were between 10 and 100 ng L-1. The proposed method was used to analyze four UV filters in natural water samples. ©2013 Sociedade Brasileira de Química.

Atividade proteolìtica de bactérias psicrotróficas em leites estocados em diferentes temperaturas

The widespread use of cooling technology as a tool for maintaining the microbiological and organoleptic characteristics of milk, Without effective hygienic practices throughout the milk production, caused the psychrotrophic micro-organisms to become major deteriorative bacteria in the dairy industry. The present study aimed to assess how the proteolytic psychrotrophic metabolism responds to different milk storage temperatures, drawing a parallel among psychrotrophic growth, amount of micro-organisms capable of breaking down proteins and amount of GMP (glycomacropeptide) released. Milk samples were collected directly from the cooling tank and subjected to count of psychrotrophs, count of proteolytic micro-organisms and the concentration of GMP at different storage times and temperatures. There was no linearity between the microbiological parameters and the GMP measured, according to the time/temperature binomial. The highest concentration of GMP (5.07 mg/mL) was measured in the binomial 8°C/24h (T8/ M24). The data make clear the need for further studies about questions involving the psychrotrophic microbiota in order to clarify extremely important basic questions about their metabolism.

Cost-effective composite electrode for the fast voltammetric screening and determination of riboflavin (B2) and pyridoxine (B6) in pharmaceuticals

Different solid composites made by mechanical dispersions of graphite particles into heated paraffin (from 65 to 80% graphite, in mass) were prepared and assessed in order to optimize their use in electrochemical and electroanalytical procedures for bioanalysis. Besides these, composites were also evaluated by thermoanalytical techniques aiming to study their conservation and long-term stability (over eight months without special care), among others. Best results were found at 80% m/m graphite in paraffin. Such electrode combines low-cost, stability, sensitivity, ease of maintenance and clearance, besides the possibilities of manufacture in many different forms and shapes (with or without modifications) and applicability in a wide range of pH. Electrochemical studies by different voltammetric techniques involving vitamins from complex B (riboflavin and pyridoxine) leaded to a better understanding about their electrooxidative processes onto carbon-composite electrodes, specially regarding reversibility and pH-dependence. Data were also acquired and optimized with analytical purposes, being square-wave voltammetry in pH 4.2 chosen by its many advantages. Good linearity between peak responses as function of concentration were reached from 5 to 43 μmol L-1 for riboflavin (peak at -0.257 V) and up to 8.5 × 10-4 mol L -1 for pyridoxine (peak at +1.04 V), best studied conditions; limits of detection (at an S/N of 3) for both analites showed to be circa 1.0 mol L-1. Different commercial samples were analyzed for riboflavin (EMS® complex B syrup) and pyridoxine (Citoneurin 5000 Merck® ampoules) providing 96.6% and 98.7% recoveries, respectively.

Matrix Effects on Water Analysis for Alkylphenols Using Solid Phase Extraction Gas Chromatography-Mass Spectrometry

Gas chromatography with mass spectrometry is frequently used for the quantification of many classes of substances, including alkylphenols. Alkylphenol polyethoxylates are nonionic surfactants used in a wide variety of industrial and consumer applications. Alkylphenol polyethoxylates can degrade to alkylphenols, which are endocrine disruptors. In analytical validation procedures, the most common parameters studied are the detection and quantification limits, linearity, and recovery; however, the matrix effects are sometimes neglected. Although some investigators have evaluated matrix effects, there is no consensus on how to evaluate them during method validation. In this study, the matrix effects of alkylphenol polyethoxylates (nonylphenol monoethoxylate, nonylphenol diethoxylate, octylphenol monoethoxylate, octylphenol diethoxylate) and alkylphenols (nonylphenol and octylphenol) were studied using solid phase extraction and gas chromatography-mass spectrometry analysis. For alkylphenol polyethoxylates, the matrix effects ranged from 16 to 4692%, whereas for alkylphenols (nonylphenol and octylphenol), the effects were insignificant. Therefore, constructing an analytical curve in the matrix for alkylphenol polyethoxylates is essential. © 2013 Copyright Taylor and Francis Group, LLC.

Atributos da validação do método analítico para quantificação da biotina empregando a técnica potenciométrica

Pós-graduação em Alimentos e Nutrição - FCFAR

Efeito da estocagem a curto prazo e da temperatura sobre gametas de jundiá, Rhamdia quelen (Quoy & Gaimard, 1824)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Determinação da velocidade de um objeto, a partir de uma seqüência de imagens, aplicando as equações de colinearidade modificadas

Pós-graduação em Ciências Cartográficas - FCT

Análise teórica e experimental de um método interferométrico de detecção de fase óptica, auto-consistente e com elevada faixa dinâmica, aplicado à caracterização de atuadores piezoelétricos flextensionais

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Análise teórica de uma nova técnica de processamento de sinais interferométricos baseada na modulação triangular da fase óptica

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Medição da descarga de peso de indivíduos hemiplégicos e não hemiplégicos utilizando uma nova plataforma de força

Pós-graduação em Engenharia Elétrica - FEIS

Demodulação de sinais interferométricos de saída de sensor eletro-óptico de tensões elevadas utilizando processador digital de sinais

Pós-graduação em Engenharia Elétrica - FEIS

Fenômenos não-lineares, incluindo-se os não-ideias, em captura de energia utilizando-se dispositivos piezoelétricos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Utilização de redes neurais recorrentes na caracterização de cargas não lineares em sistemas elétricos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)