Constituição de professores universitários de disciplinas sobre ensino de Química

This paper focuses on the teaching development practice in the field of chemistry covering such disciplines as chemistry teaching practice, chemistry teaching instrumentation and chemistry teaching methodology and/or didactics, thereby describing and analysing the logics of the development practice and the role of teachers as well as the epistemological identity configurations (knowledges which are proper to said identity) within this discipline field.

Comportamento de cristalização de lipídios estruturados obtidos a partir de gordura de palmiste e óleo de peixe

The aim of this study is to evaluate the crystal structure of binary mixtures of palm kernel fat and fish oil, before and after chemical and enzymatic interesterification. The crystal structure was analyzed by polarized light microscopy. The addition of fish oil didn't change the palm kernel fat crystallization characteristics, spherullites of types A and B being observed. However, due to chemical and enzymatic interesterification, smaller crystals were obtained. There was no difference between chemical and enzymatic interesterification, probably as a function of acyl migration in discontinuous processes catalyzed by lipases.

Extração de esterase de fígado suíno (PLE)

A simple, fast and low-cost methodology was optimized, seeking preparation of a crude pig liver esterase (PLE) concentrate. Basically, the method consisted of the following steps: liver homogenization, acetone washing, enzyme extraction and purification/concentration. Starting from 1 kg of fresh liver more than 200 kU of PLE suspension were obtained after 8 hours, at an estimated cost of US$0.21/kU. The PLE concentrate thus obtained was stable, showing 96-100% of the initial activity after 7 months in refrigerator at 4°C.

Avaliação da reação foto-fenton na decomposição de resíduos de carrapaticida

Experimental procedures based on factorial design and surface response methodology were applied to establishe experimental conditions for the decomposition of a 1:400 (v/v) Supocade® (chlorfenvinphos 13.8% and cypermethrin 2.6%) solution, used to control cattle ticks. Experiments exploring photo-oxidative reactions were performed with and without UV radiation, fixing exposition time and pesticide volume, and varying the oxidant mixture. The use of 3.6 mmol L-1 Fe2+ plus 1.9 mol L-1 H2O2 plus UV radiation provided destruction of 94% of the original carbon content and reduction of aromatic, aliphatic and carbinolic compounds, evaluated by determination of residual carbon content by ICP OES and NMR analysis.

Validação da metodologia da avaliação de incerteza em curvas de calibração melhor ajustadas por polinômios de segundo grau

The most widespread literature for the evaluation of uncertainty - GUM and Eurachem - does not describe explicitly how to deal with uncertainty of the concentration coming from non-linear calibration curves. This work had the objective of describing and validating a methodology, as recommended by the recent GUM Supplement approach, to evaluate the uncertainty through polynomial models of the second order. In the uncertainty determination of the concentration of benzatone (C) by chromatography, it is observed that the uncertainty of measurement between the methodology proposed and Monte Carlo Simulation, does not diverge by more than 0.0005 unit, thus validating the model proposed for one significant digit.

Propriedades eletrônicas, estruturais e constantes elásticas do ZnO

The electronic, structural properties and elastic constants of the wurtzite phase of zinc oxide, ZnO, was investigated using computer simulation at Density Functional Theory level, with B3LYP hybrid functional and Hartree-Fock methodology. The electronic properties as well the band energy was investigated through the analysis of the band structures and density of states (DOS), and the mechanical properties was studied through the calculus of the elastic constants C11, C33, C44, C12 e C13. The results are in good agreement with experimental data found in the literature and in accordance with results obtained by another theoretical methodology.

Desenvolvimento de métodos de análise por CLAE-UV para os antimicrobianos tetraciclina, sulfametoxazol e trimetoprima utilizando materiais à base de sílica como sistemas de pré-concentração

This paper evaluates the adsorption capacity of zirconocene-based silica materials in the pre-concentration of antimicrobians (tetracycline, sulfamethoxazole and trimethoprim) in aqueous medium. These materials were prepared by grafting the zirconocene onto silicas pre-treated at different temperatures. The retention capacity of these materials was evaluated by off line SPE and HPLC-UV and the proposed methodology was validated in ultrapure, tap and river water. The recovery for tetracycline was 72% (in the solid phase A) and, for sulfamethoxazole and trimethoprim was 68 and 95% in the commercial C18, respectively. The target antimicrobians were not detected in the Arroio Dilúvio (Porto Alegre - RS).

Otimização das condições de extração de saponinas em Ampelozizyphus amazonicus usando planejamento experimental e metodologia de superfície de resposta

This works describes the use of experimental design and surface response methodology for optimization of saponin extraction from Ampelozizyphus amazonicus. For this purpose, a method employing extraction based on maceration assisted by ultrasound technique was utilized. The following factors were studied: extraction length of time and solvent composition. The total saponin was determined by using a gravimetric method and the results expressed by their relative proportion to total crude extract. For the specific condition, 60% hydro-alcoholic solution and 18 minutes extraction length of time has shown the best results. This method can be useful for extraction of substances with biological importance

Físico-química experimental: uma proposta para abordar equilíbrio de fases em sistemas ternários

On undergraduate courses, practical classes represent periods in which students can verify the concepts presented in theoretical classes. Conversely, the teaching internship in graduate programs allows these students to incorporate pedagogical practices into their experience, predominantly involving observation and reproduction of methods adopted by supervisors. We propose internship teaching as a period for reflection on our pedagogical practice and present a methodology for an experimental physical chemistry classroom. The students can interact with the experiment and instructor, furthering the study of ternary systems while developing their skills for investigative work.

Use of experimental design in the optimisation of a solid phase preconcentration system for Cobalt determination by GFAAS

In this work is proposed a solid phase preconcentration system of Co2+ ions and its posterior determination by GFAAS in which fractional factorial design and response surface methodology (RSM) were used for optimization of the variables associated with preconcentration system performance. The method is based on cobalt extraction as a complex Co2+-PAN (1:2) in a mini-column of polyurethane foam (PUF) impregnated with 1-(2-pyridylazo)-naphthol (PAN) followed by elution with HCl solution and its determination by GFAAS. The chemical and flow variables studied were pH, buffer concentration, eluent concentration and preconcentration and elution flow rates. Results obtained from fractional factorial design 2(5-1) showed that only the variables pH, buffer concentration and interaction (pH X buffer concentration) based on analysis of variance (ANOVA) were statistically significant at 95% confidence level. Under optimised conditions, the method provided an enrichment factor of 11.6 fold with limit of detection and quantification of 38 and 130 ng L-1, respectively, and linear range varying from 0.13 to 10 µg L-1. The precision (n = 9) assessed by relative standard deviation (RSD) was respectively 5.18 and 2.87% for 0.3 and 3.0 µg L-1 cobalt concentrations.

Implementation of a trauma registry in a brazilian public hospital: the first 1,000 patients

OBJECTIVE: Show the steps of a Trauma Registry (TR) implementation in a Brazilian public hospital and evaluate the initial data from the database.METHODS: Descriptive study of the a TR implementation in João XXIII Hospital (Hospital Foundation of the state of Minas Gerais) and analysis of the initial results of the first 1,000 patients.RESULTS: The project was initiated in 2011 and from January 2013 we began collecting data for the TR. In January 2014 the registration of the first 1000 patients was completed. The greatest difficulties in the TR implementation were obtaining funds to finance the project and the lack of information within the medical records. The variables with the lowest completion percentage on the physiological conditions were: pulse, blood pressure, respiratory rate and Glasgow coma scale. Consequently, the Revised Trauma Score (RTS) could be calculated in only 31% of cases and the TRISS methodology applied to 30.3% of patients. The main epidemiological characteristics showed a predominance of young male victims (84.7%) and the importance of aggression as a cause of injuries in our environment (47.5%), surpassing traffic accidents. The average length of stay was 6 days, and mortality 13.7%.CONCLUSION: Trauma registries are invaluable tools in improving the care of trauma victims. It is necessary to improve the quality of data recorded in medical records. The involvement of public authorities is critical for the successful implementation and maintenance of trauma registries in Brazilian hospitals.

The brain decade in debate: IV. Chronobiology

The present article is the adapted version of an electronic symposium organized by the Brazilian Society of Neuroscience and Behavior (SBNeC) which took place on June 14, 2000. The text is divided into three sections: I. The main issues, II. Chronodrugs, and III. Methods. The first section is dedicated to the perspectives of chronobiology for the next decade, with opinions about the trends of future research being emitted and discussed. The second section deals mostly with drugs acting or potentially acting on the organism's timing systems. In the third section there are considerations about relevant methodological issues concerning data analysis.

Development of the Food List for a Brazilian Total Diet Study

The objective of this paper is to establish a methodology for the Food List for the southeastern region of Brazil, according to the Total Diet Study (TDS) harmonized methodology at international level. The Food List can provide data for a further TDS with evaluation of essential and toxic element dietary intakes by food analysis in laboratories. The food consumption data source used was from 2008-2009 Household Budget Survey, by the Brazilian Institute of Geography and Statistics. The Food List was composed of 82 food items grouped into 19 food groups. It reflects 100% of the daily individual food consumption inside and outside Brazilian southeastern population households. According to the recommendation that each country should carry out their own TDS and the TDS methodology used, the Food List construction can contribute to the Food List of other Brazilian regions and other countries, besides allowing the TDS development. Additionally, the Food List showed the typical diet for the southeastern region of Brazil.