• O PLC 180/2008: um projeto de lei que não olha para os problemas da educação e inclui propostas excêntricas para a seleção no ensino superior Editorial

    Chaimovich, Hernán
  • Montmorilonita modificada como catalisador heterogêneo em reações de esterificação (m)etílica de ácido láurico Artigo

    Zatta, Leandro; Nepel, Angelita; Barison, Andersson; Wypych, Fernando

    Abstract in English:

    ABSTRACT Montmorillonite was modified with zirconium polyoxycations in the presence of ammonium sulphate. The material was characterized and used as a catalyst in the esterification of lauric acid, the reactions being accompanied by 2³ factorial design. Conversions of up to 95.33 and 83.35% were observed for the methyl and ethyl esterification reactions respectively, proving superior to results obtained by thermal conversion. The material was submitted to three reaction cycles and similar conversions were observed, indicating the catalyst is not significantly deactivated after reuse. The catalyst was also tested under reflux conditions, yielding a maximum conversion of 36.86%.
  • Basic properties of potassium oxide supported on zeolite y studied by pyrrole-tpd and catalytic conversion of methylbutynol

    Nuttinee, Supamathanon; Jatuporn, Wittayakun; Sanchai, Prayoonpokarach; Wojciech, Supronowicz; Frank, Roessner

    Abstract in English:

    ABSTRACT We report on the basic properties of zeolite NaY and potassium supported on NaY (K/NaY) assessed by pyrrole-TPD and MBOH transformation. Pyrrole-TPD revealed that impregnation of zeolite NaY with potassium promoted additional adsorption sites for pyrrole compared to parent zeolite. For zeolite with various potassium loadings, pyrrole adsorbed on K/NaY decreased with increased potassium loading. Reduction in pyrrole adsorption could be due to potassium hindering intrinsic basic sites (lattice oxygen), to oxide of potassium occluding in zeolite cavities restricting access for pyrrole, or to K2O reacting with pyrrole to form nondesorbed pyrrolate anions. On MBOH transformation, potassium almost completely suppressed NaY acid sites while K/NaY basicity increased with potassium loading.
  • A comparative study of hydroxyapatite nanoparticles synthesized by different routes

    Paz, Adrian; Guadarrama, Dainelys; López, Mónica; E. González, Jesús; Brizuela, Nayrim; Aragón, Javier

    Abstract in English:

    In this study, bioactive hydroxyapatite nanoparticles were prepared by two different methods: wet chemical precipitation and biomimetic precipitation. The aim was to evaluate the morphology, particle-size, crystallinity and phases of the powders obtained by traditional wet chemical precipitation and the novel biomimetic precipitation using a supersaturated calcium solution. The nanoparticles were investigated by transmission electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. The results revealed that the nanoparticles were formed by hydroxyapatite with a high crystallinity and controlled morphology. Additionally, it was found that the shape and size of the nanoparticles can be modified with each preparation method.
  • Ácidos fenólicos, flavonoides e atividade antioxidante em méis de Melipona fasciculata, M. flavolineata (Apidae, Meliponini) e Apis mellifera (Apidae, Apini) da Amazônia Artigo

    Oliveira, Patricia Sertão; Müller, Regina Celi Sarkis; Dantas, Kelly das Graças Fernandes; Alves, Claudio Nahum; Vasconcelos, Marcus Arthur Marçal de; Venturieri, Giorgio Cristino

    Abstract in English:

    Honey produced by three stingless bee species (Melipona flavolineata, M. fasciculata and Apis mellifera) from different regions of the Amazon was analyzed by separating phenolic acids and flavonoids using the HPLC technique. Data were subjected to multivariate statistical analysis (PCA, HCA and DA). Results showed the three species of honey samples could be distinguished by phenolic composition. Antioxidant activity of the honeys was determined by studying the capacity of inhibiting radicals using DPPH assay. Honeys with higher phenolic compound contents had greater antioxidant capacity and darker color.
  • Método QuEChERS para determinação de ocratoxina a e citrinina em arroz e farelo de arroz Artigo

    Hackbart, Helen C. dos S.; Souza, Michele Moraes de; Scaglioni, Priscila Tessmer; Primel, Ednei G.; Garda-Buffon, Jaqueline; Badiale-Furlong, Eliana

    Abstract in English:

    The present study was carried out to establish the optimal conditions for performing ochratoxin A (OTA) and citrinin (CIT) extraction using the QuEChERS method in rice. Employing the factorial experimental design, variables that significantly influenced the extraction stages were determined. The following variables were analyzed: addition of water, acidification of acetonitrile with glacial acetic acid, as well as amounts of magnesium sulfate, sodium acetate, sodium citrate and diatomaceous earth. The best combining procedure resulted in a predictive model using more water and less diatomaceous earth. Recoveries of CIT and OTA were 78-105%.
  • Aplicação de técnicas multivariadas e inteligência artificial na análise de espectros de infravermelho para determinação de matéria orgânica em amostras de solos Artigo

    Souza, Diego M.; Madari, Beata E.; Guimarães, Freddy F.

    Abstract in English:

    In this paper studies based on Multilayer Perception Artificial Neural Network and Least Square Support Vector Machine (LS-SVM) techniques are applied to determine of the concentration of Soil Organic Matter (SOM). Performances of the techniques are compared. SOM concentrations and spectral data from Mid-Infrared are used as input parameters for both techniques. Multivariate regressions were performed for a set of 1117 spectra of soil samples, with concentrations ranging from 2 to 400 g kg-1. The LS-SVM resulted in a Root Mean Square Error of Prediction of 3.26 g kg-1 that is comparable to the deviation of the Walkley-Black method (2.80 g kg-1).
  • Absorção de bário por plantas de arroz (Oryza sativa L.) e mobilidade em solo tratado com baritina sob diferentes condições de potencial redox Artigo

    Lima, Erica Souto Abreu; Amaral Sobrinho, Nelson Moura Brasil do; Magalhães, Marcio Osvaldo Lima; Guedes, Jair do Nascimento; Zonta, Everaldo

    Abstract in English:

    Two parallel tests were carried out to evaluate barium solubility in soils treated with barite under reducing conditions: one in leaching columns and another with potted plants cultivated with rice. Soils were treated with three doses of barite and kept at two humidity levels. The reduction (-200 mV) condition promoted an increase in barium in the geochemical fraction of higher liability, higher concentrations of barium in the leached extracts, and higher absorption by rice plants. As a result of increased uptake and accumulation of barium, the plants showed stunted growth
  • Estudo teórico e experimental de espectros infravermelho de ésteres de ácido graxo presentes na composição do biodiesel de soja Artigo

    Castilho-Almeida, Eduardo W.; Santos, Hélio F. Dos; Miranda, Alisson Marques de; Jorio, Ado; Ferreira, Erlon H. Martins; Achete, Carlos Alberto; Armond, Raigna A. S. Z.; Anconi, Cleber Paulo A.; Almeida, Wagner Batista De

    Abstract in English:

    In this work, theoretical and experimental infrared spectra of fatty acid methyl esters (FAME) contained in soybean biodiesel were analyzed seeking the assignments of the relevant vibrational modes to characterize crude soybean oil and soybean biodiesel. The results showed the usefulness of infrared spectra for monitoring saturated and unsaturated compounds as well as impurities (mainly glycerol) in raw samples. This is the first step toward proposing an efficient molecular spectroscopy routine to certify biodiesel fuel.
  • Synthesis and biological evaluation of biaryl analogs of antitubulin compounds

    Tozatti, Camila Santos Suniga; Khodyuk, Rejane Gonçalves Diniz; Silva, Adriano Olimpio da; Santos, Edson dos Anjos dos; Amaral, Marcos Serrou do; Lima, Dênis Pires de; Hamel, Ernest

    Abstract in English:

    This paper reports the synthesis of methanones and esters bearing different substitution patterns as spacer groups between aromatic rings. This series of compounds can be considered phenstatin analogs. Two of the newly synthesized compounds, 5a and 5c, strongly inhibited tubulin polymerization and the binding of [³H] colchicine to tubulin, suggesting that, akin to phenstatin and combretastatin A-4, they can bind to tubulin at the colchicine site.
  • Optimization of wood flour acetylation by factorial design and partial least squares regression

    Nadal, Lisandra M. K.; Cararo, Daniele C.; Pinheiro, Luís A.; Prestes, Rosilene A.

    Abstract in English:

    Acetylation was performed to reduce the polarity of wood and increase its compatibility with polymer matrices for the production of composites. These reactions were performed first as a function of acetic acid and anhydride concentration in a mixture catalyzed by sulfuric acid. A concentration of 50%/50% (v/v) of acetic acid and anhydride was found to produced the highest conversion rate between the functional groups. After these reactions, the kinetics were investigated by varying times and temperatures using a 3² factorial design, and showed time was the most relevant parameter in determining the conversion of hydroxyl into carbonyl groups.
  • Classificação de resíduos de madeira tratada com preservativos à base de arseniato de cobre cromatado e de boro/flúor Artigo

    Ferrarini, Suzana Frighetto; Santos, Heldiane Souza dos; Miranda, Luciana Gampert; Azevedo, Carla M. N.; Pires, Marçal J. R.; Maia, Sandra Maria

    Abstract in English:

    Classification of waste wood treated with chromated copper arsenate (CCA) and boron/fluorine preservatives, according to NBR 10004, was investigated. The leaching test (ABNT NBR 10005) for As and Cr, and solubilization test (ABNT NBR 10006) for F, were applied to out-of-service wooden poles. Concentrations of As and Cr in leachates were determined by ICP-MS and of F by ESI. Values for As were higher than 1 mg L-1 classifying the waste as hazardous material (Class I) whereas values for F (> 1.5 mg L-1) were non-hazardous but indicated non-inert material (Class IIA).
  • Zn-edta degradation by catechol-driven fenton reaction

    Oviedo, Claudia; Berrocal, Alexander; Navarrete, José; Mansilla, Héctor; Contreras, David

    Abstract in English:

    Zn-EDTA degradabilty by catechol-driven Fenton reaction was studied. Response surface methodology central composite design was employed to maximize this complex degradation. Theoretical speciation calculations were in good agreement with the experimental results. Fenton and Fenton type treatments are typically thought to be applicable only in the highly acidic range, representing a major operational constraint. Interestingly, at optimized concentrations, this CAT-driven Fenton reaction at pH 5.5 achieved 100% Zn-EDTA degradation; 60% COD and 17% TOC removals, using tiny amounts of CAT (50 µM), Fe(III) (445 µM) and H2O2 (20 mM) with no evident ferric sludge.
  • Síntese, caracterização e estudo das propriedades magnéticas de um polímero de coordenação contendo cobalto(II) e cobre(II) Artigo

    Cunha, Tamyris T. da; Stumpf, Humberto O.; Pereira, Cynthia L. M.; Pires, Heber S.; Oliveira, Luiz F. C. de; Pedroso, Emerson F.; Nunes, Wallace C.

    Abstract in English:

    This work describes the synthesis and characterization of two new compounds with ligand opy (N-(2-pyridyl)oxamate): the copper(II) precursor [Me4N]2[Cu(opy)2].5H2O and CoII CuII coordination polymer {[CoCu(opy)2]}n×4nH2O. This latter compound was obtained by reaction of [Me4N]2[Cu(opy)2].5H2O and CoCl2.6H2O in water. The heterobimetallic CoII CuII chain was characterized by elemental analysis, IR spectroscopy, thermogravimetry and magnetic measurements. Magnetic characterization revealed typical behavior of one-dimensional (1D) ferrimagnetic chain as shown in the curves of temperature (T) dependence of magnetic susceptibility (χM), in the form of χMT versus T, and dependence of magnetization (M) with applied field (H).
  • Hydrolytic activity of bacterial lipases in amazonian vegetable oils

    Willerding, André Luis; Carvalho Neto, Francisco Geraldo Mello da Rocha; Gama, Auricélia Matos da; Carioca, Cláudia Regina Ferreira; Oliveira, Luiz Antonio de

    Abstract in English:

    The data presented describe the development of an enzymatic process in vegetable oils. Six bacterial lipases were tested for their ability to hydrolyze. For each lipase assay, the p-NPP method was applied to obtain maximum enzymatic activities. The lipase from Burkholderia cepacia (lipase B-10) was the most effective in buriti oil, releasing 4840 µmol p-NP mL-1. The lipase from Klebsiella variicola (lipase B-22) was superior in passion fruit oil, releasing 4140 µmol p-NP mL-1 and also in babassu palm oil, releasing 2934 µmol p-NP mL-1. Research into the bioprocessing of oils aims to provide added value for this regional raw material.
  • Efeitos das condições ambientais sobre o teor e variabilidade dos óleos voláteis de dalbergia frutescens (Vell.) Britton (Fabaceae) Artigo

    Mendes, Caroline Eliza; Casarin, Fabiana; Ohland, Anderson Luis; Flach, Adriana; Costa, Luiz Antonio Mendonça Alves da; Denardin, Rosiane Berenice Nicoloso; Moura, Neusa Fernandes de

    Abstract in English:

    The volatile oils of Dalbergia frutescens were obtained by hydrodistillation on a Clevenger-modified apparatus for every month of one year and assessed on GC/MS and GC/FID detectors for qualitative and quantitative analyses. The influence on content of volatile oils was directly proportional to the environmental variables, temperature and cloudiness, and inversely proportional to precipitation. Among the volatile compounds detected, linalool, β-damascenone, α-ionone, geranyl acetone and β-ionone were the main components, of which β-damascenone and β-ionone were found at the highest concentrations.
  • Caracterização e classificação quanto ao risco ambiental do estéril da mina de cromita do município de Andorinha, Bahia Artigo

    Teixeira, Aline Maria dos Santos; Garrido, Francisco M. S.; Medeiros, Marta Eloisa; Sampaio, João Alves

    Abstract in English:

    The mineral waste studied was host rock from a chromite mine located in Andorinha/Bahia, extracted and stockpiled in yards without specific application. Host rock was submitted to chemical analysis, XRD, SEM-EDS, IR and TGA and classified according to ABNT standards for solid waste classification. Analyses confirmed that this host rock, classified as ultrabasic, consists mainly of dolomite, calcite and diopside. Hazard assessment results showed this host rock should be classified as class II B - inert waste, important for its potential application in agriculture as a soil acidity correction agent.
  • Theoretical investigation of electronic excitation transfer between chlorophylls in light-harvesting antenna of photosystem ii using quantum computers

    Dehestani, Maryam; Shojaei, Somaie; Khosravan, Azita

    Abstract in English:

    The excitation energy transfer between chlorophylls in major and minor antenna complexes of photosystem II (PSII) was investigated using quantum Fourier transforms. These transforms have an important role in the efficiency of quantum algorithms of quantum computers. The equation 2n=N was used to make the connection between excitation energy transfers using quantum Fourier transform, where n is the number of qubits required for simulation of transfers and N is the number of chlorophylls in the antenna complexes.
  • Chemical composition, circadian rhythm and antibacterial activity of essential oils of piper divaricatum: a new source of safrole

    Barbosa, Queila P. S.; Câmara, Cláudio A. G. da; Ramos, Clécio S.; Nascimento, Daniele C. O.; Lima-Filho, José V.; Guimarães, Elsie F.

    Abstract in English:

    The essential oils from leaves, stems and fruits of Piper divaricatum were analyzed by GC-MS. The tissues showed high safrole content: leaves (98%), fruits (87%) and stems (83%), with yields of 2.0, 4.8 and 1.7%, respectively. This is a new alternative source of safrole, a compound widely used as a flavoring agent and insecticide. The leaf's oil showed antibacterial activity against gram-negative bacteria while safrole was active against Salmonella Typhimurium and Pseudomonas aeruginosa. In addition, the study of circadian rhythm of the safrole concentration in the essential oils of leaves showed a negligible variation of 92 to 98%.
  • Avaliação do transporte do ácido 2,4-diclorofenoxiacético através de um lisímetro Artigo

    Macedo Neto, Daniel; Froehner, Sandro; Machado, Karina Scurupa

    Abstract in English:

    The objective of this study was to evaluate the transport of one of the most toxic and best-selling herbicides in Brazil. The active ingredient 2,4-dichlorophenoxyacetic acid (2,4-D) was applied onto the surface of a tank-type lysimeter, filled with undisturbed soil, in Curitiba, Parana State. Samples of infiltration and runoff water were obtained during rain simulations. The concentrations of the active ingredient 2,4-D showed a rapid decrease in the environment, with mass losses of 29.12% by infiltration and 0.87% by runoff.
  • Caracterização de chás de genótipos de Lippia gracilis schauer através de perfil cromatográfico por CLAE-DAD combinado com análises quimiométricas Artigo

    Prado, Vilma Menezes de Jesus; Moraes, Valéria Regina de Souza; Nogueira, Paulo Cesar de Lima; Cruz, Elizangela Mércia Oliveira; Blank, Arie Fitzgerald; Pereira-Filho, Edenir Rodrigues; Martins, Lúcia Regina Rocha

    Abstract in English:

    In order to evaluate the effects of environmental factors on the content of secondary metabolites, the chemical profiles of infusions from leaves of seven genotypes of Lippia gracilis Schauer, sourced from two locations (Sergipe and Bahia state) and collected during different seasons: summer (with and without irrigation) and winter, were determined by HPLC-DAD. The fingerprint chromatograms were analyzed by PCA to evaluate similarities and differences among the samples. Results revealed differences among genotypes collected and cultivated under the same conditions, suggesting that three genotypes have greater resistance to drought conditions.
  • A fração volátil das aguardentes de cana produzidas no Brasil Revisão

    Moreira, Ricardo F. A.; Netto, Claudia C.; Maria, Carlos A. B. de

    Abstract in English:

    The volatile fraction of sugar cane spirits plays a key role in the quality and acceptance of these beverages. The composition of this fraction is dependent on the way sugar cane collection, fermentation, distillation and aging are carried out. The materials used in these processes strongly influence chemical composition. Acetic acid, acetaldehyde, ethyl acetate, ethanol, 2.3-butanedione, n-propanol, 3-methyl-buthanol and isobuthanol were the major volatiles in spirits. Dimethyl sulfide and n-propanol impaired beverage flavor. Ethyl octanoate, 1.1-diethoxy-ethane, 2-phenylethanol and 3-methyl-butanol were important aroma contributors. Ageing allows the extraction of flavor-active components (e.g., phenolic compounds) from wood.
  • Nanoemulsões como sistemas de liberação parenteral de fármacos Revisão

    Bruxel, Fernanda; Laux, Manoela; Wild, Luisa Bartmann; Fraga, Michelle; Koester, Letícia S.; Teixeira, Helder F.

    Abstract in English:

    Lipid nanoemulsions have recently been proposed as parenteral delivery systems for poorly-soluble drugs. These systems consist of nanoscale oil/water dispersions stabilized by an appropriate surfactant system in which the drug is incorporated into the oil core and/or adsorbed at the interface. This article reviews technological aspects of such nanosystems, including their composition, preparation methods, and physicochemical properties. From this review, it was possible to identify five groups of nanoemulsions based on their composition. Biopharmaceutical aspects of formulations containing some commercially available drugs (diazepam, propofol, dexamethasone, etomidate, flurbiprofen and prostaglandin E1) were then discussed.
  • Princípios fundamentais e modelos de transferência de energia inter e intramolecular Revisão

    Souza, Ernesto R.; Sigoli, Fernando A.

    Abstract in English:

    This work outlines the historic development of the concept and main theories of energy transfer, as well as the principal experiments carried out to confirm or refute the proposed theories. Energy transfer in coordination compounds is also discussed with a focus on rare earth systems.
  • Desenvolvimento, produção e caracterização de nanocristais de fármacos pouco solúveis Revisão

    Fangueiro, Joana F.; Marques, Inês R.; Severino, Patrícia; Santana, Maria Helena A.; Souto, Eliana B.

    Abstract in English:

    Poorly soluble drugs have low bioavailability, representing a major challenge for the pharmaceutical industry. Processing drugs into the nanosized range changes their physical properties, and these are being used in pharmaceutics to develop innovative formulations known as Nanocrystals. Use of nanocrystals to overcome the problem of low bioavailability, and their production using different techniques such as microfluidization or high pressure homogenization, was reviewed in this paper. Examples of drugs, cosmetics and nutraceutical ingredients were also discussed. These technologies are well established in the pharmaceutical industry and are approved by the Food and Drug Administration.
  • Isolamento do tungstênio da volframita da mina de Igarapé Manteiga (Rondônia - Brasil) por lixiviação ácida Nota técnica

    Paulino, Jéssica Frontino; Afonso, Julio Carlos; Mantovano, José Luiz; Vianna, Cláudio Augusto; Cunha, José Waldemar Silva Dias da

    Abstract in English:

    We report results of the efficiency of tungsten extraction from wolframite concentrate (containing 61.5 wt % WO3) from the Igarapé Manteiga mine (state of Rondônia, Brazil) through acid leaching with strong mineral acids at 100 ºC and 400 rpm for 2-4 h. HCl yielded insoluble matter containing the highest WO3 content (90 wt %). This solid was dissolved in concentrated NH3(aq) at 25 ºC and the insoluble matter filtrated. The filtrate was slowly evaporated. 70 wt % of the tungsten present in the starting concentrate material was recovered as ammonium paratungstate (APT).
  • Avaliação de métodos de extração para a determinação de cromo e níquel em formulações farmacêuticas e em matérias-primas usadas na fabricação de medicamentos à base de cefalexina e ciprofloxacino Nota técnica

    de Paula, Carlos Eduardo R.; Brum, Daniel M.; Caldas, Luiz Fernando S.; Cassella, Ricardo J.

    Abstract in English:

    This paper reports the evaluation of extraction strategies for the treatment of medicine samples to determine chromium and nickel by GFAAS. Different approaches for extraction were evaluated and the most efficient involved magnetic stirring. The metals were quantitatively extracted by stirring 0.20 g samples with 25 mL of 2.0 mol L-1 HCl solution for 60 min. The developed method was successfully applied for the determination of Cr and Ni in tablets containing antibiotics and raw materials, with cephalexin and ciprofloxacin as active ingredients.
  • Impacto ambiental de kartódromos situados na cidade do Rio de Janeiro: monitoramento de BTEX no ar e do nível de ruído Nota técnica

    Laurentino, Lauro de Sena; Marques, Mônica Regina da Costa; Corrêa, Sérgio Machado

    Abstract in English:

    In this work, noise and aromatic hydrocarbons levels of indoor and outdoor karting circuits located in Rio de Janeiro were assessed. The sampling was perfomed using active charcoal cartridges, followed by solvent desorption and analysis by gas chromatography with mass spectrometry detection. This study demonstrated that the karting circuits, venues for entertainment, were a major source of air pollution with the detection of considerable amounts of these compounds (2.0 to 19.7 µg m-3 of benzene; 4.1 to 41.1 µg m-3 of toluene; 2.8 to 36.2 µg m-3 of ethylbenzene; 0.7 to 36.2 µg m-3 of xylenes) and high noise levels.
  • Montagem de uma prensa para fios de sódio metálico Nota técnica

    Oliveira, Alfredo R. M. de; Oliveira, Amanda Chaves de

    Abstract in English:

    Several organic chemistry labs in Brazil suffers from the absence of a safe method to extrude sodium wire, used to obtain anhydrous solvents such as THF or ethyl ether. This technical note presents the assembly instructions for a sodium wire press, similar to the one that has been used for the past four years in our laboratory without any maintenance.
  • Preparação de nanopartículas de prata e ouro: um método simples para a introdução da nanociência em laboratório de ensino Educação

    Melo Jr., Maurício Alves; Santos, Lucas Samuel Soares; Gonçalves, Maria do Carmo; Nogueira, Ana Flávia

    Abstract in English:

    A new practical experiment involving silver and gold nanoparticle syntheses was introduced in an inorganic chemistry laboratory course for undergraduate students at the Institute of Chemistry, UNICAMP. The nanoparticles were synthesized by the reduction of silver nitrate and tetrachloroauric acid with sodium borohydride and sodium citrate in an aqueous medium. Stabilities of the suspensions were tested using several different reactants including sodium chloride, polyvinylpyrrolidone, polyvinyl alcohol and cistamine. Changes in optical properties were observed by electronic spectra and also by transmission electronic microscopy, which also yielded data for estimating particle size.
  • Novas métricas holísticas para avaliação da verdura de reações de síntese em laboratório Educação

    Ribeiro, Maria Gabriela T. C.; Machado, Adélio A. S. C.

    Abstract in English:

    New semi-quantitative metrics for simple evaluation of global greenness of chemical reactions used in teaching laboratories, namely, the Green Circle (GC) and Green Matrix (GM), were developed. These metrics globally consider all Twelve Principles of Green Chemistry. To illustrate their construction, the greenness of several syntheses performed in the laboratory under different sets of conditions was assessed. The tools were validated by comparing the results with another metric, the Green Star (GS), developed in our previous study. Results showed these new metrics were useful for the intended purpose, having the advantage of being simpler than the GS.
  • Polarímetro virtual: desenvolvimento, utilização e avaliação de um software educacional Educação

    Silva Júnior, José Nunes da; Barbosa, Francisco Geraldo; Leite Junior, Antonio José Melo

    Abstract in English:

    Optical activity is the ability of chiral substances to rotate the plane of plane-polarized light and is measured using an instrument called a polarimeter. An educational software application to explore, both interactively and visually, the concepts related to polarimetry to facilitate their understanding was developed. The software was field-tested and a questionnaire evaluating the graphics interface, usability and the software as an educational tool, was answered by students. The results characterized the computer application developed as an auxiliary tool for assisting teachers in lectures and students in the learning process.
  • Síntese da fenitoína assistida por micro-ondas: proposta de aula prática para alunos de graduação Educação

    Konrath, Eduardo L.; Piedade, Maristela; Eifler-Lima, Vera Lucia

    Abstract in English:

    Microwave synthesis is considered a breakthrough in the field of chemistry due to its benefits over conventional heating methods. We describe, for the first time, the total synthesis of phenytoin adapted for a microwave reactor, proposed as an experiment for undergraduate courses. When carried out with microwaves, the synthetic route provided phenytoin in 6 min and 30 s, while for conventional heating the total time was 170 min. The experiment also involves rapid identification of compounds by TLC, ¹H NMR, FT-IR and melting points determination.
  • Desenvolvimento sustentável e pensamento complexo: estudo de caso: o uso de argilas como catalisadores Assuntos gerais

    Souza, Soraia P. L. de; Marques, Mônica R. da C.; Mattos, Marcio C. S. de

    Abstract in English:

    Use of clays as catalyzers in heterogeneous processes has increased significantly given their low cost, safety and commercial availability. However, interconnected political, economic, social, environmental, geological, and chemical aspects should be considered for chemical processes to satisfy sustainable development concepts. This concept requires complex thinking involving different areas of knowledge in dialogue, contrasting with classical thought, which is linear and Cartesian. Thus, this paper discusses the principles of complex thought in the concept of sustainable development exemplified by use of clay as a clean technology in organic synthesis.
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