Mesoporous carbon-containing voltammetric biosensor for determination of tyramine in food products

A voltammetric biosensor based on tyrosinase (TYR) was developed for determination of tyramine. Carbon material (multi-walled carbon nanotubes or mesoporous carbon CMK-3-type), polycationic polymer—i.e., poly(diallyldimethylammonium chloride) (PDDA), and Nafion were incorporated into titania dioxide sol (TiO(2)) to create an immobilization matrix. The features of the formed matrix were studied by scanning electron microscopy (SEM) and cyclic voltammetry (CV). The analytical performance of the developed biosensor was evaluated with respect to linear range, sensitivity, limit of detection, long-term stability, repeatability, and reproducibility. The biosensor exhibited electrocatalytic activity toward tyramine oxidation within a linear range from 6 to 130 μM, high sensitivity of 486 μA mM(−1) cm(−2), and limit of detection of 1.5 μM. The apparent Michaelis–Menten constant was calculated to be 66.0 μM indicating a high biological affinity of the developed biosensor for tyramine. Furthermore, its usefulness in determination of tyramine in food product samples was also verified. [Figure: see text] ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00216-016-9612-y) contains supplementary material, which is available to authorized users

Durability Analysis of Natural Lime Concrete

Concrete is known to be durable and dependable material since it is resistance to weathering action and chemical attacks while maintaining its engineering properties. However, carbon dioxide produced by the cement industries had caused severe environmental pollution. To minimize carbon dioxide emission into the atmosphere, eggshell wastes are treated as partial cement replacement in this study. The eggshell was oven-dried at 105.5 °C for 24 h before grinding it into powder passing through sieve size 45 µm. Eggshell powder was used as partial cement replacement at 5, 10, 15 and 20%. The performance of the concrete mix was evaluated against control concrete mix. The specimens were tested on acid attack and sulphate attack. The concrete specimens were prepared in the form of cubes and then subjected to water curing for 28 days before immersed in sulphuric acid solution for 1800 h and sodium sulphate for 50 weeks respectively. From the analysis, it is observed that reduction of compressive strength of the concrete cubes for the acid attack and sulphate attack reduce gradually when the eggshell powder increase

Desempenho de escolares em provas de processo de identificação de letras e do processo léxico

RESUMO Objetivo: caracterizar, comparar e correlacionar o desempenho de escolares brasileiros do 2º ao 5º ano do Ensino Fundamental do ensino público e particular em provas de avaliação do processo de identificação de letras e do processo léxico. Métodos: participaram 262 escolares do Ensino Fundamental (público= 122, particular= 140), do interior paulista: Ensino público - G1 (2º ano, n=24); G2 (3º ano, n=33); G3 (4º ano, n= 31); G4 (5º ano, n=34) e Ensino particular - G5 (2º ano, n=37); G6 (3º ano, n=34); G7 (4º ano, n=34); G8 (5º ano, n=35). Aplicadas Provas do processo de Identificação de Letras e Léxico do PROLEC. Resultados: os escolares do ensino particular apresentaram desempenho médio superior, com exceção da prova Igual-Diferente entre os grupos G1-G5 e G3-G7. As diferenças foram maiores entre os escolares até o 4º ano devido ao uso frequente da rota fonológica, sugerindo diferença no ensino do princípio alfabético entre as escolas públicas e particulares. Para o 5º ano, não houve diferença nas provas em que as palavras podem ser lidas pela rota lexical. Conclusão: os escolares do ensino particular apresentaram desempenho superior, com exceção das provas em que a rota fonológica não é a unicamente exigida. Contudo, no início da alfabetização, a rota fonológica foi mais utilizada do que a lexical, independente do tipo de ensino. Este estudo mostra a necessidade de o sistema de ensino priorizar na alfabetização a relação letra-som, de modo que os escolares de escola pública possam apresentar melhores resultados em decodificação que podem influenciar diretamente a compreensão e leitura

Supporting Literacy and Digital Literacy Development in Early Childhood Education Using Storytelling Activities

Educators have increasingly adopted formalized approaches for teaching literacy skills in early childhood education. In line with an emergent critique of this approach, the present study investigated the design and effectiveness of a literacy intervention that blended Gagné’s nine events of instructional design with storytelling. Three classes in a public preschool in Indonesia participated in an experimental study involving 45 children, aged 5–6 years. Across 3 weeks, one experimental condition received storytelling activities and a second experimental condition received digital storytelling activities. The control condition received regular literacy classroom activities. Before, and after, the 3-week storytelling intervention, measures of literacy and digital literacy skills were administered to all groups. In the digital storytelling condition, children’s literacy skills increased significantly compared to children in the control condition. Other exploratory data analyses suggested that both types of storytelling activities enhanced digital literacy skills. The findings need to be replicated with an extended series of storytelling activities that involve larger groups of participants