Uso de software como ferramenta pedag��gica no processo de ensino-aprendizagem da mamografia digital

OBJETIVO: Avaliar o impacto sobre o treinamento de residentes utilizando uma ferramenta computacional dedicada �� avalia����o do desempenho da leitura de imagens radiol��gicas convencionais e digitais. MATERIAIS E M��TODOS: O treinamento foi realizado no Laborat��rio de Qualifica����o de Imagens M��dicas (QualIM). Os residentes de radiologia efetuaram cerca de 1.000 leituras de um total de 60 imagens obtidas de um simulador estat��stico (Alvim��) que apresenta fibras e microcalcifica����es de dimens��es variadas. O desempenho dos residentes na detec����o dessas estruturas foi avaliado por meio de par��metros estat��sticos. RESULTADOS: Os resultados da probabilidade de detectabilidade foram de 0,789 e 0,818 para os sistemas convencional e digital, respectivamente. As taxas de falso-positivos foram de 8% e 6% e os valores de verdadeiro-positivos, de 66% e 70%, respectivamente. O valor de kappa total foi 0,553 para as leituras em negatosc��pio e 0,615 em monitor. A ��rea sob a curva ROC foi de 0,716 para leitura em filme e 0,810 para monitor. CONCLUS��O: O treinamento proposto mostrou ser efetivo e apresentou impacto positivo sobre o desempenho dos residentes, constituindo-se em interessante ferramenta pedag��gica. Os resultados sugerem que o m��todo de treinamento baseado na leitura de simuladores pode produzir um melhor desempenho dos profissionais na interpreta����o das imagens mamogr��ficas.

Conhecimento escolar em qu��mica: processo de media����o did��tica da ci��ncia

xThe aim of this article is to present a contribution of the school knowledge research to Chemistry Teaching. The object of research is school knowledge on physical sciences, considering the existence of a rupture between scientific knowledge and everyday knowledge. The differences between analogies and metaphors and the process of didactic mediation were thoroughly examined. The conclusion is that the process of didactic mediation is built on their own cognitive configurations, which not always make public the private scientific knowledge to certain social groups.

Desenvolvimento de um processo de lixivia����o dos concentrados de mangan��s em sais fundidos

The NaCl- KCl system as fused-salt solvent for leaching has shown to have some advantages over traditional solvents. In this work the solubility of copper, nickel and cobalt oxide in this system, as impurities in manganese concentrate, was studied. The euthetic mixture of NaCl - KCl at 700��C was used at several fusion times and the dissolved metals were determined by Atomic Absorption Spectrometry. The results have shown that in these conditions only copper was solubilized.

Simula����o do processo Solvay no laborat��rio did��tico

The Solvay Process is an important route for the industrial preparation of sodium carbonate from brine and CO2. However, experiments illustrating such process are performed only in a few chemistry courses, mainly because of the difficulties to precipitate out the intermediate product NaHCO3 within the 3 or 4 hours generally available for laboratory classes. In this article we describe a method that properly simulates the Solvay process using glass apparatus that can be found in any chemistry laboratory. The good yields and purity attainable, associated with the short time (~3 hours) required to get the sodium bicarbonate, account for the suitability of our method for chemistry or chemical engineering undergraduate students laboratory classes.

Modelo te��rico qu��ntico para o processo de adsor����o f��sica

This article introduces a simplified model for the theoretical study of the physical adsorption process of gaseous He on the planes (100) and (111) of the solid Xe matrix, whose crystalline structure is face centered cubic (fcc). The Ab initio calculations were carried out at the MP2 level of theory employing basis sets obtained through the Generator Coordinate Method, where the core electrons were represented by a pseudopotential. The calculated adsorption energies for the (100) and (111) faces are 5,39 and 4,18 kJ/mol, respectively. This simplified model is expected to be suitable for treating complex systems of applied interest.

O processo de latencia����o no planejamento de f��rmacos

Short review about the main aspects of prodrug design, as its objectives, applicability and importance, showing the new trends in the research for selective latent forms, namely targeted drugs.

Processo qu��mico industrial de extra����o de ��leo vegetal: um experimento de qu��mica geral

In this study we describe an experimental procedure based on a chemical industrial process of soya-bean oil extraction applied in general chemistry for undergraduate students. The experiment was planned according to the Science, Technology and Society (STS) approach to teach basic chemical concepts and provide grounding in the management of environmental care. The use of real life chemistry problems seems to salient the relevance of chemistry to our students and enhances their motivation to learn both the practical and theoretical components of the discipline.

Processo alternativo para remo����o de cobre (II) e n��quel (II) de solu����es aquosas utilizando c��psulas de quitosana - ��lcool Polivin��lico

Capsules were prepared from chitosan (QTS)-poly(vinyl alcohol) (PVA) blend by saline coacervation and then by formalization. A adsorbent based on chitosan, insoluble on acid solution, was obtained. The morphology, average diameters of QTS/PVA capsules and their pores were studied by using scanning electron microscopy. The entrapment-adsorption of dimethylglioxime and ethylenediaminetetracetate by the capsules were studied. The removal of the ion nickel (II) and copper (II), was more effective than by using unloaded capsules.