Marcos da história da radioatividade e tendências atuais

The first days of radioactivity, the discoveries of X-rays, radioactivity, of alpha- and beta- particles and gamma- radiation, of new radioactive elements, of artificial radioactivity, the neutron and positron and nuclear fission are reviewed as well as several adverse historical marks, such as the Manhattan project and some nuclear and radiological accidents. Nuclear energy generation in Brazil and the world, as an alternative to minimize environmental problems, is discussed, as are the medicinal, industrial and food applications of ionizing radiation. The text leads the reader to reflect on the subject and to consider its various aspects with scientific and technological maturity.

Quinina: 470 anos de história, controvérsias e desenvolvimento

After 470 years, a history of development, international seed smuggling and scientific development that caused deep changes in our society, has reached an end. In 1638, the countess of Chinchón contracted a disease while in the Amazon rain forest and was healed by a potion used by the native inhabitants. In 1856, William H. Perkin while attempting to obtain synthetic quinine, discovered the mauveína, a molecule that changed the world. The synthesis of quinine was also the subject of a bitter controversy among two excellent scientists of the 20th century. During centuries, quinine was the only hope against malaria disease and its exploration almost extinguished the Cinchona tree.

Irradiação de micro-ondas aplicada à síntese orgânica: uma história de sucesso no Brasil

This review article shows the publications in the field of microwave irradiation published by Brazilian researchers over the past 10 years. In South America, Brazil leads the publication of articles with the use of microwave irradiation possessing a large advantage in number of articles published over the others countries. The works were divided into four major areas: Catalysis, Reactions without Solvent, Heterocycles Chemistry, Natural Products and Other, and some could be classified in more than one category.

Efeitos da história térmica nas propriedades do polímero pet: um experimento para ensino de análise térmica

Polyethilenetherephtalate (PET) is commonly used in manufacturing of beverage bottles representing a didactic appeal in thermal analysis education due to its presence in the student's day life. Additionally such polymer presents well defined thermal analytical curves and a well known thermal behavior. TGA curve is used to present the thermal stability. The thermal history effects in the thermal properties of a PET sample from a soft drink bottle are used to demonstrate the effect of different heating/cooling conditions on glass transition, melting, crystallization and crystalline degree using DSC curves.

Investigando a presença da história da ciência em livros didáticos de Química Geral para o ensino superior

This paper aims at analyzing the history of science content of three general chemistry textbooks used in Brazilian universities: the translations of Kotz and Treichel's Chemistry & Chemical Reactivity, Atkins and Jones's Chemical Principles, and Garritz and Chamizo's Química. Results revealed different trends for the inclusion of history of science in chemistry teaching. Kotz & Treichel and Atkins & Jones used history mainly as curiosity and ornament. Garritz & Chamizo adopted the historical approach as one of the organizing axis of their textbook. Nevertheless, the historical content of the three textbooks may be criticized from current historiographical standpoint.