RESUMO
It is well established that emotions play a key role in the teaching-learning process and cognitive and affective factors should receive especial consideration. This fact becomes even more important when dealing with pre-service teachers, since their emotions towards science will be projected into their future practice as early-childhood teachers. It has been also stated the influence of the instructional approach in which the teaching-learning process is based on the emotions of students towards science. In this line, the current study aims to monitor and interpret the emotions of pre-service teachers when addressing physics content learning, namely forces, from two different instructional approaches with increasing experimentality degree and implication of students. The considered instructional approaches consisted on a theoretical problem solving one and a practical one designed in the form of inquiry-based hands-on activities. A sample size of 118 students was considered and a questionnaire was employed for in situ emotions monitorization. A decrease from 30% to 12% in negative emotions and an increase from 85% to 91% in positive emotions was detected when considering the transition from instructional approach 1 (classroom approach) to instructional approach 2 (inquiry-based hands-on approach). The whole dataset was analyzed by means of principal component analysis (PCA). PCA reveals the importance of emotions' valence, but also their activating/deactivating character. An approach to epistemic emotions is achieved from this perspective. It has been demonstrated that the implementation of inquiry-based hand-on activities results in increased occurrence of security and trust among the students, in comparison with occurring emotions after receiving more theoretical interventions.
RESUMO
Glyoxal and methylglyoxal are two important markers of oxidative stress and both are involved in the evaluation of several diseases. A new HPLC method for determining glyoxal and methylglyoxal in urine was developed. The method is based on the reaction of alpha-dialdehydes, glyoxal and methylglyoxal, with 5,6-diamino-2,4-hydroxypyrimidine sulfate in basic medium to form highly fluorescent lumazine derivatives. Creatinine was also included in the method even though it does not react with the reagent. The derivatives and creatinine are separated on a C(18) reversed-phase column with a mobile phase consisting of acetonitrile:citrate buffer, pH 6.0 (3:97 v/v). The flow rate was 1.0mLmin(-1) and the effluent was monitored photometrically at 250 nm for determination of creatinine and fluorimetrically at 500 nm (exciting at 330 nm) for determination of glyoxal and methylglyoxal derivatives. Recording time of the separation is less than 10 min. Determination of the analytes is performed in urine after incubation of the sample, with the reagent in alkaline medium, for 30 min at 60 degrees C. Urinary levels of glyoxal and methylglyoxal, expressed as glyoxal/creatinine and methylglyoxal/creatinine ratios, in healthy young women and men were determined. For women, values of 0.80+/-0.37 and 0.60+/-0.22 microg/mg of creatinine were found for glyoxal and methylglyoxal, respectively. For men, values of 0.63+/-0.15 and 0.49+/-0.05 microg/mg of creatinine were found for glyoxal and methylglyoxal, respectively. These results were also related to the body mass index of each individual.