Schistosomiasis is one of the major public health problems worldwide. Even though this is a common illness among preschool children in poor countries, treatment is carried out mainly through the administration of praziquantel tablets, which has some disadvantages, such as the strong bitter taste. As an alternative to overcome this problem, the development of new encapsulated praziquantel formulations is demanded. For this reason, suspension polymerizations are carried out for the in situ encapsulation of praziquantel into polymer microparticles, using methyl methacrylate (MMA) and cationic compounds (diethylaminoethyl methacrylate, DEAEMA, and dimethylaminoethyl methacrylate, DMAEMA) as comonomers. This technique allows for the preparation of polymer microparticles with high encapsulation efficiencies (>90%) with characteristic sizes ranging from 0.5 to 1500 µm. Drug release profiles show that praziquantel is released from poly(methyl methacrylate) microparticles slowly due to the existence of strong diffusional resistance. On the other hand, the addition of cationic comonomers renders polymer particles sensitive to pH variations, allowing for faster release of praziquantel in acidic environments, as found in the stomach.

Neste trabalho mostraremos como obter a lei do inverso do quadrado da distância para a intensidade luminosa emitida por uma fonte pequena de uma maneira muito simples, rápida e com boa precisão. Com o auxílio de dois smartphones, aplicativos grátis e uma régua somos capazes de medir as distâncias entre os dispositivos citados (um como fonte e outro como medidor de intensidade luminosa) e as respectivas intensidades luminosas medidas por um dos aparelhos. A facilidade de reprodução do experimento e a penetração do uso de tablets e smartphones entre os estudantes e professores pode fazer com que a atividade proposta se torne uma boa alternativa para a introdução de fenômenos físicos que exibem a mesma dependência funcional, tais como a lei da gravitação universal de Newton e a lei de Coulomb.

The late trends in special education policy aim to maintain in the same school system students with and without special needs. In the case of students with visual impairment, one of the main problems they face, particularly in physics, is the lack of instructional materials adapted to the experimental laboratory. In this paper we present strategies, activities and resources for instructional use by the physics teacher in a classroom with students with visual impairment, using tactile sensations produced by laser light to teach optics concepts. For best results, we suggest that teachers use resources from a perspective of building models in order to stimulate interest and active involvement of the student.

No presente trabalho temos como objetivo apresentar alguns questionamentos com respeito à abordagem utilizada em alguns livros didáticos de nível médio sobre o tema de ondas sonoras estacionárias em tubos. Além de classificar os livros didáticos dentro de um conjunto de critérios estabelecidos, apresentamos também algumas sugestões para uma discussão mais aprofundada deste tema. Sugerimos o uso de gifs e animações e a utilização de dois experimentos simples, que permitem a visualização dos perfis de variação de pressão e deslocamento de ar para os modos harmônicos de vibração.

We use a tablet to determine experimentally the dependencies of the magnetic field (B) on the electrical current and on the axial distance from a coil (z). Our data shows a good precision on the inverse cubic dependence of the magnetic field on the axial distance, B ∝ z −3 . We obtain with good accuracy the value of air permeability µair. We also observe the same dependence of B on z when considering a magnet instead of a coil. Although our estimates are obtained through simple data fits, we also perform a more sophisticated error analysis, confirming the result for µair. PACS numbers:The use of tablets and smartphone in science education expands possibilities for approaches that motivate students to understand better several physical phenomena [1][2][3][4]. In particular, tablets were shown as good tools to measure magnetostatic responses in current-carrying wires. This interesting work is about magnetic field sensoring [1]. It reports a simple way of obtaining experimentally the linear dependence between the magnetic field B and the number of turns N in the current-carrying coil using an "app" for iPad [5]. However, additional dependences of B are still not discussed, some of which we show in this paper leading to a wider description of this kind of system.We determine the dependencies of B on the electric current I and on the axial distance z in a coil, in suitably conditions using an iPad and the same free app MagnetMeter [5] (we suggest a similar app for Android [6]). We also perform the similar experiments with a small magnet instead of a coil. For the coil, we also make a good estimate for the magnetic permeability of the air µ air ∼ = µ 0 ≡ 4π × 10 −6 Hm −1 . The demonstration set used is composed by an electrical circuit, a ruler and a book. The circuit is formed by the following components, all of them connected in series: a wirewound potentiometer with resistance up to 30Ω; a resistor with 10Ω; an electrical source from a cell phone (max. output current ∼ 0.9A); a digital multimeter and a coil (internal diameter 2R i = 1.91 cm and external diameter 2R e = 2.42 cm and N = 62 turns).