Abstract: This article describes the chemical composition of Vernonia chalybaea essential oil, and investigates its antimicrobial, antioxidant and hemolytic activities. The evaluation of the antifungal activity was performed by the broth microdilution method using strains of yeasts and dermatophytic fungi. The checkerboard technique to find antimicrobial modulatory effects was performed using ketoconazole as standard drug. The antioxidant activity was evaluated by DPPH scavenging assay and β-carotene/linoleic-acid system. The toxicity was characterized by the brine shrimp lethality test and hemolysis bioassays. The essential oil was obtained by hydrodistillation and analyzed by GC-MS method, showing to be rich in the sesquiterpenes β-caryophyllene (39.06%) and bicyclogermacrene (19.69%), and also demonstrated a relevant antifungal activity against strains of Trichophyton rubrum. In the modulatory activity assay, the essential oil of V. chalybaea and β-caryophyllene demonstrated a synergistic interaction with ketoconazole, with increasing of its antifungal action. The antioxidant activity was evidenced mainly by β-carotene/linoleic acid system, with IC50 value of 35.87 ± 0.32 µg/mL. The results suggest that V. chalybaea essential oil and β-caryophyllene are valuable natural medicinal agents with antioxidant and antimicrobial activities.

The importance of teaching scientific communication skills in undergraduate chemistry courses is well recognized. This paper provides an overview of didactic activities in which students engage to improve these skills. The study was based on an extensive literature review performed on the Journal of Chemical Education and on the Journal of College Science Teaching, in the years spanning from 1991 to 2010, and on The Chemical Educator, from 1996 to 2010. The findings from the study provided an opportunity to expand the knowledge on the variety of methods and contents used to teach scientific communication skills in undergraduate chemistry education, as well as to deepen our understanding of the effects of different approaches to teaching on performance in practice.

This study aimed to analyze the aspects of scientific language considered by chemistry professors in the evaluation of scientific texts authored by undergraduate chemistry students. Interviews were conducted with four professors who had evaluated reports and scientific articles written by students enrolled in undergraduate chemistry courses. The professors highlighted aspects pertaining to the structure and general organization of scientific texts typically adopted by the scientific community, and mentioned the importance of certain rhetoric elements in scientific language. This study can be an impetus for further investigation into the importance of language in chemistry education.

In this article we describe a peer review exercise used in undergraduate chemistry course in which the students wrote and prepared critique of scientific texts produced by other students in the class. We investigated, based on the critical comments made by the peers, evidences of the appropriation of scientific discourse and a better understanding of its practice by the students. Additionally, we present our own conclusions on the use of such exercise applied to an organic chemistry course offered to undergraduate chemistry students at a Brazilian public university

En este artículo se describe un ejercicio de revisión de pares empleado en un curso de la licenciatura en química, en el cual los estudiantes escribieron y prepararon una crítica a los textos científicos producidos por otros estudiantes de la clase. Se investigaron, con base en los comentarios críticos realizados por los pares, las evidencias de la apropiación del discurso científico y una mejor comprensión de su práctica por los estudiantes. Adicionalmente, se presentan nuestras propias conclusiones sobre tal ejercicio aplicado en un curso de química orgánica ofrecido en una universidad pública brasileña.

This work is part of a study that focused on analyzing the contributions of didactic activities related to scientific language rhetoric characteristics aimed at developing students' abilities to identify such characteristics in chemistry scientific texts and critical reading of those texts. In this study, we present the theoretical basis adopted to determine the scientific discourse characteristics and for the production of the didactic material used in those activities. Latour, Coracini and Campanario studies on persuasive rhetorical strategies present in scientific articles aided the production of such material.

The purpose of this study was to analyze written arguments found within laboratory reports by undergraduate students in a practical inorganic chemistry course. The quality of students' argumentation was analyzed based on the argumentation model developed by Kelly and Takao. Students presented scientific arguments grounded in data and building toward theoretical assertions. This indicates that students have some understanding of the rhetorical power of data in their explanations. The findings of this study also support the idea that Kelly and Takao's model is effective in other disciplines and in other rhetorical tasks distinct from those originally analyzed by them in their domain of oceanography.

O objetivo deste trabalho foi analisar as visões de alunos de pós-graduação sobre as necessidades formativas de professores de Química do Ensino Superior. A partir de questões relacionadas ao "saber" e "saber fazer" do professor neste nível de ensino, os alunos apresentaram suas concepções sobre os conhecimentos necessários para um bom desempenho na prática de sala de aula. Os resultados demonstraram que a maioria dos alunos priorizou a necessidade do professor conhecer a matéria a ser ensinada, ou seja, os saberes conceituais. Aliado a este saber, porém em menor grau, destacaram a importância dos saberes relacionados à metodologia de ensino da área específica.

The aim of this work was to analyze views of graduate students about the professional background of undergraduate chemistry professors. Graduate students answered a questionnaire about the knowledge and the know-how necessary as attributes of undergraduate chemistry professors. The results indicated that the majority of students prioritized the need of extensive knowledge of the discipline to be taught. Besides, they also highlighted the importance of knowledge of subject-related teaching methodology.

In the present work, we provide some considerations about the role of scientific communication in Chemistry Education. Such considerations may subsidize the development of communication in scientific language by Chemistry students. These considerations are based on information collected during a participatory research for the production of didactic material about scientific communication. The meetings were audio recorded and the contents of the participants' speeches were divided into categories. The category analysis supported the elaboration of the considerations.