Doutorado em Química (IQ)
URI Permanente para esta coleção
Navegar
Navegando Doutorado em Química (IQ) por Título
Agora exibindo 1 - 20 de 112
Resultados por página
Opções de Ordenação
Item O acidente radiológico de Goiânia e seus desdobramentos nos currículos da licenciatura em Química em Goiás: uma leitura freireana(Universidade Federal de Goiás, 2021-11-02) Nunes, Luclécia Dias; Mesquita, Nyuara Araújo da Silva; http://lattes.cnpq.br/6971106875143413; Mesquita, Nyuara Araújo da Silva; Soares, Marlon Herbert Flora Barbosa; Silva Filho, Juvenal Carolino da; Genovese, Cinthia Letícia de Carvalho RoversiIn Goiânia, in 1987, a radiological accident occurred with a Cesium 137 source, which could have been avoided if those involved had basic knowledge about some symbols related to the scientific context and to Radioactivity, which highlights the role of the school and teachers with regard to scientific literacy. Thus, this research sought to understand the relationship between the theme Radioactivity and scientific literacy, in the formation of Chemistry teachers, in the state of Goiás and the possible implications for their teaching performance. For this, a reading of the radiological was made from the Freireana perspective, seeking to understand the social relations that emerged in the context of the actions imbricated in the history of the accident. We also analyzed the PPC for degrees in Chemistry offered by the IES in the state and questionnaires sent to basic education teachers, in order to identify whether the courses include the theme Radioactivity and the accident in focus, so that we can understand, in terms of teacher training and action, the obliterating reflexes of the (non)approach to the Radioactivity theme in initial training for a pedagogical practice that considers scientific literacy as a (trans)forming element. In the analytical process, two a priori categories were used: the formation of Chemistry teachers in the state of Goiás and scientific literacy; and the approach of Radioactivity in the training of Chemistry teachers and na emerging category: the influences of initial training in relation to the theme Radioactivity in the teaching performace of Chemistry teachers in basic education. As a theoretical interlocutor for this tese and for data analysis, we used the theoretical framework from Paulo Freire. By analyzing the first category, we see that in the PPC there is evidence that the IES are conducting the training of undergraduates in Chemistry through the bias of scientific literacy, as all documents bring elements that indicate a pedagogical proposal that seeks to train teachers through a critical and reflective considering elements that characterize the formation for citizenship. In the processo of analyzing the second category, it was observed that of the 16 IES that offer the degree course in Chemistry, nine PPC have disciplines that somehow address the theme Radioactivity, three PPC have specific disciplines on the theme, but only one explicit in its menu that will address nuclear accidents. The analysis of the questionnaries showed that the teachers either did not study on the theme, or studied it superficially and the accident was little discussed, which reverberated in their teaching performance. Thus, what we infer from the analyzed documents was that, although there are indications that guide the reader initially to glimpse that the undersgraduate are being trained in the perspective of being prepared to, in their future teaching action, act as Chemistry teachers, who literate their students scientifically, the work as a whole shows that this training will most likely not be achieved in relation to the theme Radioactivity. Because, in general, teachers trained in Chemistry at the IES in the state of Goiás do not have opportunities to learn and discuss Radioactivity content and, specially the accident with Cesium 137, therefore, they are not prepared to scientifically literate education students basic in relation to theme Radioactivity.Item Água em condição supercrítica: uma tecnologia versátil para o tratamento de efluentes industriais e produção de hidrogênio(Universidade Federal de Goiás, 2021-03-26) Ribeiro, Thiago Soares Silva; Oliveira, Sérgio Botelho de; http://lattes.cnpq.br/3447406257464639; Alonso, Christian; http://lattes.cnpq.br/7285754665946583; Oliveira, Sérgio Botelho de; Aranda , Donato Alexandre Gomes; Cardozo Filho, Lúcio; Antoniosi Filho, Nelson Roberto; Oliveira, Guilherme Roberto deIndustrial processes bring with them an important concern: the correct management of waste generated, whether solid, liquid or gaseous. Among the various types of industrial wastewater, those generated in pharmaceutical industries that produce hormonal drugs or in biodiesel producing plants stand out for their polluting potential and high organic load, respectively. Therefore, it is essential to perform the appropriate treatment of these industrial wastewater, which does not occur in many of the conventional processes used in wastewater treatment stations (WTS). In this scenario that the objective of this work was to treat samples of hormonal (synthetic (EHS) and industrial (EHI)) wastewater, in addition to samples of wastewater from a biodiesel producing plant (EPB) using the process with supercritical water (SCWP), in a continuous flow reactor in the absence of catalysts, aiming at the degradation of contaminants and obtaining hydrogen gas, syngas and other fuel gases. The use of samples with such a different chemical composition is justified by the intention to evaluate the versatility of the wastewater treatment via SCWP for both environmental and energy purposes. The liquid phase was characterized by the determination of physical-chemical parameters such as total organic carbon (TOC), Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), Oils and Greases (OG), pH, nitrogen compounds, metals, among others, in addition to high performance liquid chromatography (HPLC), for EHS samples, mass spectrometry (EM), and phytotoxicity tests with cucumber seeds (Cucumis sativus). The gas phase was characterized by gas chromatography (GC). Regarding the reduction of TOC, it was possible to reduce between 80% and 90% of TOC in the EHS samples for most of the feed flow rate conditions evaluated at 700 °C and for the EHI samples the maximum value of 89 was obtained, 6% reduction in TOC at the highest temperature evaluated. In EPB samples, the maximum TOC reduction value reached was 98.8%. The other physical-chemical parameters analyzed point to the same trend: the higher the temperature and the spatial time, the greater the efficiency of the process in relation to the reduction of physical-chemical parameters. The phytotoxicity tests against cucumber seeds, indicate a significant reduction in the toxic effect of the chemical compounds present in the initial samples, in treatments from 600 °C. The results of mass spectrometry point to the predominance of esters and fatty acids in both samples analyzed. The characterization of the gases showed that the production of hydrogen gas stands out among the other gases, and the amount produced in the treatment of EPB samples (885.9 NmL(H2)/mL (powered EPB)) indicates several possibilities of using this gas in industrial processes such as Ammonia Production, Production of new compounds via Fischer-Tropsch process, Fuel cells, Burning as fuel, Hydrotreated vegetable oil (HVO) manufacturing processes, Power-to-X technologies (PtX). In view of the results, it is possible to infer that the treatment of organic contaminants via SCWP is quite promising for both energy and environmental purposes.Item Análise de síntons intermoleculares de bases N-heterocíclicas e suas correlações com propriedades óticas(Universidade Federal de Goiás, 2021-12-17) Valdo, Ana Karoline Silva Mendanha; Martins, Felipe Terra; http://lattes.cnpq.br/0466799995060671; Martins, Felipe Terra; Guimarães, Freddy Fernandes; Nakahata, Douglas Hideki; Santana, Ricardo Costa de; Araujo Neto, João Honorato deOne of the aims of crystal engineering is the analysis of synthons. The understanding of synthons formation allows modifying them to obtain chemical and physical properties of interest. Among those properties, structure dependents, are optical and electronic properties. The second harmonic generation (SHG) is one example of nonlinear optics phenomena and has a great potential aaplication. In this area, several organic compounds, such as nitrogenous aromatic ones, show SHG. Although robust synthons exist, their modification is delicate, since various parameters induce their formation. Moreover, the SHG has a requirement of inversion center absence in the structure. In this context, guiding structure to specific symmetries are still a crystallographic hard task. In this work the synthons of monoprotonated nitrogenous aromatic compounds salts were analyzed. The salts were synthesized throughout the reaction of nitrogenous compounds (dissolved in isopropanol) with organic and inorganic acids. The used compounds belong to the classes of pyrimidines and pyrazines. After the synthesis, the acidified solutions were submitted to crystallization using the slow evaporation technique. The single crystals had their X-Ray Diffraction data collected. Yet, reflectance diffuse spectroscopy data were collected for some samples. Further, calculations of electronic structure to obtain geometric optimization and spectra absorption data were performed. These calculations were done with density functional theory (and time-dependent density functional theory), with the functional M06-2X or B3LYP and the base 6-31G** or Def2-TZV. In this study fifteen unpublished structures were obtained, among which only one was solved in a noncentrosymmetic space group. The analyses of synthons in all structures revealed two tendencies. The first was observed for the structures obtained from 2-aminopyrazine. In those structures, the protonation of 2-aminopyrazine nitrogen (from aromatic ring) not depended on exclusively of 𝑝𝑘𝑎 from compounds, but also has relation with the final synthons. Accordingly, it was possible to noted that not only a chemical propriety dictates the protonation in the formation of a crystalline medium. Beyond that, the energy of finals intra and intermolecular interactions were essential to understand this result. The other tendency was verified for the compound derived of 2-aminopyrazine substituted by halogen atoms in the aromatic ring, in which, the synthons for the aromatic compounds with or without halogen atoms were the same. Thus, it was observed that a structural modification as an insertion of a halogen atom did not alter the interactions pattern in aromatic compounds. Regarding the physical properties, the direct band gap value for some nitrogenous compound was determined experimentally. Finally, we related the approximationof theoretical and experimental data on electronic transition with the energy of synthons or interactions for a set of atoms present in the structures. For some data, we observed that the greater the stability of the interactions involved, the closer were the theoretical data to the experimental one for the electronic transitions. However, this did not extend to all datasets analyzed in this work.Item Aplicações bionalíticas do imageamento químico por técnicas de ionização ambiente de espectrometria de massas: DESI e LAESI(Universidade Federal de Goiás, 2020-03-20) Vasconcelos, Géssica Adriana; Vaz, Boniek Gontijo; http://lattes.cnpq.br/7814534710550639; Vaz, Boniek Gontijo; Kato, Lucília; Severino, Vanessa Gisele Pasqualotto; Romão, Wanderson; Martins, Aline Maria AraújoRecent advances in mass spectrometry allowed the study of samples with little or no sample preparation. Among these techniques, Desorption Electrospray (DESI) and Laser Electrospray Ionization (LAESI) has gained popularity for their ability to generate chemical images and the use of a laser to study samples under ambient conditions respectively. New DESI users may face several operational problems due to the lack of a literature describing a detailed protocol on how to work with this technique. Although there is a rich literature on DESI, scientific articles always present a brief description of how the experiments were carried out. Thus, the objective of chapter 1 was to present a simple protocol on how to perform imaging experiments by DESIMS. This chapter describes how to optimize the spot, geometric parameters and how to perform an image acquisition. The main application of the DESI imaging technique is in the medical-clinical area. Numerous researchers have investigated the chemical signatures of tumors and cancers for biomarkers that can not only assist on their identification, but also in the development of new treatments for patients. However, there are several clinical areas that have not been much explored by this technology, such as diseases caused by restricted blood flow to the brain. Models of blood flow reduction are often used in mice to simulate stroke that affects humans. Thus, chapter 2 presents the results obtained from the DESI-MS evaluation of the brain of animals after 1, 3 and 7 days after ischemia induction. 2D chemical images were generated for the most abundant ions and PSL-DA statistical analysis was used to verify the most relevant molecular species for this model. Chapter 3 presents the use of LAESI-MS technology in the study of cyanobacteria that commonly produce toxins. The chosen species are known to cause damage to aquatic bodies due to their extensive proliferation in a short period of time. The metabolic profile of each species was investigated, and statistic tools were used to observe the degree of separation between the cyanobacteria species studied. In addition, ion mobility data were used in order to increase molecular coverage and confidence in the identification of species of interest.Item Aplicações de espectrometria de massas ambiente em metabolômica clínica(Universidade Federal de Goiás, 2019-12-07) Andrade, Thais Pontes Pereira Mendes de; Vaz, Boniek Gontijo; http://lattes.cnpq.br/7814534710550639; Vaz, Boniek Gontijo; Chaves, Andrea Rodrigues; Duarte, Gabriela Rodrigues Mendes; Gil, Eric de Souza; Pinto, Mauro Cunha XavierMost clinical biofluids studies are based on plasma/serum and urine, which are more free and representative models of general metabolism. Each of these fluids has a unique matrix, comprising different levels of proteins and metabolites. Therefore, it is important to optimize sample preparation and analytical methods to achieve comprehensive coverage of the analytes present in these samples. In this context, Ambient Mass Spectrometry (AMS) arises, which is a family of desorption and ionization techniques that have revolutionized the way of obtaining ions in mass spectrometry. These techniques share the ability to generate ions in the gas phase directly from untreated samples, reducing or virtually eliminating analyte extraction and prior separation. Substrate Electrospray Ionization are ionization techniques in AMS, which comprise, for example, Paper spray ionization (PSI) and Probe electrospray ionization (PESI). In this study, two analytical approaches are proposed in clinical metabolomics using PSI and, also, the development of a new Substrate Electrospray Ionization. The first approach is the use of a paper coated by a molecularly printed polymer (MIP) as a substrate for PSI in metabolite analysis: dopamine, sarcosine and butyric acid in artificial urine. This new substrate was highly selective for the desired targets, in addition to minimizing the effects of common ion suppression on PSI. In addition, calibration curves with R2> 0.99 and limits of detection (LOD) and quantification (LOQ) in the ppb range were obtained. In addition, success was obtained when using this technique for the analysis of dopamine in a real sample. In the second approach, PSI was combined with a chemometric approach called Interval-successive projections algorithm linear discriminant analysis (iSPA-LDA) to detect lipid biomarkers of cervical cancer using unprepared blood plasma lipids. A total of 86 blood plasma samples from different women were collected, including 37 cancer controls and 49 healthy controls, where 8 lipids were found as possible biomarkers with an overall precision of 77%. The results show the potential of PSI associated with multivariate analysis as a complementary tool for the screening or diagnosis of cervical. It is the application of PSI in plasma samples in a non-targeted lipidic approach, with the objective of discovering biomarkers of cervical cancer. The final approach was to use graphite as a substrate for ESI. The effect of voltage, probe angle and sample volume were evaluated. The ionization capacity of several analytes, including a protein, has also been evaluated, and creatinine quantification tests have been performed on real urine samples. The ESI graphite technique was optimized and obtained excellent ionization of the analytes, not presenting ionic suppression. It was possible to determine the amount of creatinine present in the samples tested and all were within the established limits. In addition, the technique was employed in mouse brain analysis and through these analyzes combined with Principal Component Analysis (PCA) it was possible to differentiate different regions of the brain and separate the samples in male and female. With this, the graphite ESI technique proved very efficient to be used in metabolomic approaches.Item Aplicações dos sistemas de transferência de energia eletrônica baseados em nanoestruturas de peptídeos(Universidade Federal de Goiás, 2019-09-20) Souza, Geovany Albino de; Martins, Tatiana Duque; http://lattes.cnpq.br/9082478597898534; Martins, Tatiana Duque; Martins, Felipe Terra; Gonçalves, Pablo José; Colmati Júnior, Flávio; Zalloum, Neife LilianIn this work, we prepared a system comprised of self-assembled nanostructures of diphenylalanine (Phe-Phe) combined with the fluorophore coumarin 6 (C6) for encapsulation of perillyl alcohol (PA), a drug administered in glioma treatment. The photophysical characteristics of this system were determined through steady-state and time resolved fluorescence spectroscopies and epifluorescence microscopy. The formation of an exciplex between the Phe-Phe and C6 was identified, characterized by a stabilization of electronic excited states in the system. This finding encouraged the investigation of different applications for this system, such as sensing, drug delivery and photodynamic therapy (PDT). In this context, different fluorescence lifetimes obtained for this system in the presence and absence of oxygen (O2(g)) demonstrated the applicability of the system as a dynamic sensor for dissolved O2. Nano and microvesicles obtained from the self-assembly of this dipeptide, in the presence of C6, were used for encapsulation and release of perillyl alcohol. The drug release was triggered by induced interconversion of the vesicles to nanotubes by modification of the chemical environment and was monitored by time-resolved fluorescence spectroscopy combined to epifluorescence microscopy. The spectroscopy techniques also revealed a role of the drug in the charge transfer exciplex of Phe-Phe combined to C6, which resulted in a further stabilization of electronic excited state. Also, the singlet oxygen quantum yield was determined through indirect measurements, seeking PDT application of the new drug delivery system. Quantum yields of 0.7 and 0.8% were obtained for the C6 fluorophore and the Phe-Phe/C6 combined system, respectively. However, the quantum yield of the complete system (nano/microvesicles of Phe-Phe/C6 bearing the PA in its interior) was 3%, which represents a significant increase as a result of the unique photophysical properties found in this system. These findings show that this system has applicability derived from the combination of the therapies with perillyl alcohol and PDT as a synergistic effect between the properties of the encapsulated drug and photodynamic activity.Item Atividades de experimentação investigativas lúdicas no ensino de química:(Universidade Federal de Goiás, 2009-12-11) OLIVEIRA, Noé de; SOARES, Marlón Herbert Flora Barbosa; http://lattes.cnpq.br/9698540158266610This Thesis presents a brief historic of experimentation, its application in secondary schools and the justification for the alternative material utilised during the activities of experimentation. Some playful conceptual aspects, its presentation and its application at school are also described with the aim of observing the existence of the relations between the playful and the activities of experimentation. Referring to the method, we have opted for the method study of multiple cases, aiming to conduct a comparison amongst several students and schools that utilise different experiments in an attempt to relate the similarities to the context of the research focus. The development in the application of the activities of experimentation is described in different groups from three secondary schools, two being in the city of Dourados-MS and one in the city of Goiânia- GO. This paper also presents an analysis of several articles related to experiments published by magazines such as Química Nova (New Chemistry) and Química Nova na Escola (New Chemistry at School), taking into consideration the following criteria: the availability of activities of experimentation for the teaching of chemistry, types of experimentation, laboratory material and reagents utilised, adequacy to the classroom, type of questionnaire, relationship with daily life, and the possibility of the presence of the playful if performed by the student. The Atividade de Experimentação Investigativa Lúdica AEIL (Activity of Investigative Playful Experimentation) is being proposed as another subsidy for the practice of experimental activities, with the possibility of being performed in the classroomItem Avaliação da composição química de indivíduos adultos de araucaria angustifolia (Bert.) kutz. através da RMN aliada a quimiometria visando a distinção sexual(Universidade Federal de Goiás, 2016-12-15) Oliveira, Gerlon de Almeida Ribeiro; Lião, Luciano Morais; http://lattes.cnpq.br/2647529909397336; Lião, Luciano Morais; Barison, Andersson; Novotny, Etelvino Henrique; Zanette, Flávio; Venturoli, FábioAraucaria angustifolia, popularly known as araucaria or pine of Paraná, is an endemic conifer in the Brazilian southern and southeastern. The preserved areas represent source of income to a great number of families of collectors, due to the interest of the population for the so called “pinhão”, the seed of the araucaria. Araucaria is a dioecious plant, and only the female plants produce the “pinhão”. Determining the sex of the seedlings would be interesting so that a higher number of females than males could be planted, which would increase the production of pinhão and would make this species more attractive for reforestation purposes. There is no technique for knowing the sex of the seedlings before they express their sexuality, which occurs between fifteen and twenty years after planting. The objective of this study was to evaluate the possibility of using nuclear magnetic resonance (NMR), mass spectrometry (MS), and infrared spectroscopy in the non-targeted metabolomic approach for the sexual determination of adult individuals of araucaria. 80 samples of adult plant needles were collected in the state of Paraná, Brazil. The needles were macerated with liquid nitrogen and extracted with deuterated chloroform (NMR), or methanol (MS). Several pre-treatments were evaluated, as well as different non-supervised (clusters analysis and principal component analysis, PCA) and supervised multivariate techniques (partial least squares discriminant analysis – PLS-DA, linear discriminant analysis, LDA, after selection of variables by genetic algorithm). Using the strategy described herein, the chemometric models indicated only some trends of separation of the groups according to sex, which, however, were not generalizable.Item Avaliação da degradação do sistema isolante óleo-papel usando análise de imagens e técnicas espectroscópicas combinadas com métodos de calibração multivariada e resolução de curvas(Universidade Federal de Goiás, 2014-06-27) Godinho, Mariana da Silva; Sena, Marcelo Martins de; http://lattes.cnpq.br/7050638697696950; Oliveira, Anselmo Elcana de; http://lattes.cnpq.br/0369339073291948; Oliveira, Anselmo Elcana de; Ferreira, Márcia Miguel Castro; Ribeiro, Cacilda de Jesus; Ferri, Pedro Henrique; Lião, Luciano MoraisThe lifetime of a power transformer is determined by the state of degradation of its insulation system. This system consists of Kraft paper immersed in insulating oil (IMO). In order to prevent an abrupt crash transformer its oxidation state should be monitored. This monitoring is performed using physico-chemical and chromatographic assays. The physico-chemical parameter of greatest importance is the interfacial tension (IT), which is a measure for assessing indirectly the oxidation state of the Kraft paper. The objective of this thesis to propose analytical methodologies to evaluate the oxidation process of the insulation system, both in naturally and accelerated degraded oil samples, using Image Analysis and spectroscopic techniques combined with methods of Multivariate Calibration (Partial Least Squares - PLS), Resolution Multivariate Curve and Data Fusion. Spectra of Moleculular Fluorescence (MF), Nuclear Magnetic Resonance of 1H (1H NMR), Fourier Transform Near Infrared (FT-NIR) and RGB images were obtained for a set of 268 oil samples provided by CELG Distribuição S.A. (CELG D). Subsequently, spectra in the Ultraviolet-Visible (UV-Vis) region, FM and RGB images were obtained for a set of 24 oil samples subjected to an accelerated degradation. PLS models were obtained in order to predict the IT and color parameters for the set of samples provided by CELG D. For the set of degraded samples PLS models were obtained for prediction of degradation time. PARAFAC and MCR-ALS models were obtained to evaluate the oxidation process of the insulating system and too identify the pure spectra of possible compounds formed during this process. Furthermore, low level data fusion combined with variable selection using the Variables Importance in the Projection (VIPs) was used in this study to obtain PLS models. The best PLS model for the set of samples provided by CELG D was obtained for the fused spectroscopic data using variable selection by VIPS. This model provided a mean square error of prediction (RMSEP) of 2.9 mN/m for IT and 0.3 for the color parameter (dimensionless units). PARAFAC and MCR-ALS models allowed to assess the process of system degradation. The proposed methodologies are fast and non-destructive, showing great advantages over traditional methods, which take a long time, and generate a lot of waste. This work opens perspectives for an online monitoring to assess the degradation of the insulating system besides having permitted a more detailed study on the compounds formed during the degradation process.Item Avaliação de catalisadores à base de platina-paládio suportados em carbono para a oxidação de etanol em eletrólitos ácido e básico(Universidade Federal de Goiás, 2018-08-09) Carvalho, Leandro Lima; Colmati Júnior, Flávio; http://lattes.cnpq.br/0231242349462585; Colmati Júnior, Flávio; Tanaka, Auro Atsushi; Alonso, Chistían Gonçalves; Sgobbi, Lívia Flório; Rabelo, DenilsonThe management of the world energy matrix needs to be rethought, and in this context, the energy sector is, over all, the focus of this discussion, and the present, depends more and more on new strategies for energy production. In this way, the advances in the development of technologies about alternative sources of energy generation called Fuel Cells, mainly the electrochemical devices which working with ethanol as fuel (DEFCs). This work, the carbon supported Pt/C; Pd/C; Pt75Pd25/C; Pt75(PdOx)25/C; Pt50Pd50/C e Pt50(PdOx)50/C electrocatalysts with 20wt% of metal on carbon were prepared by fast reduction with sodium borohydride (NaBH4) followed by thermal treatment. The materials were characterized by X-ray diffraction (XRD) Transmission electron microscopy (TEM) and High resolution transmission electron microscopy (HRTEM), x-ray energy dispersive spectroscopy (EDS), cyclic voltammetry (VC) and Chronoamperometry. The EDS spectra showed e, experimental compositions of electrocatalysts are close to nominal, which suggest, high efficiency of the redactor agent BH4(aq) - /OH- (aq) for reducing the ions Pt+4 (H2PtCl6.6H2O) and Pd+2 (PdCl2.6H2O). The XRD analysis indicate the nanoparticle arrangement of the Platinum-Paladium with different content results in crystalline structure on carbon support, and the peaks assigned to Pt75(PdOx)25/C and Pt50(PdOx)50/C were observed indicating oxide formation from metal precursors Pt75Pd25/C e Pt50Pd50/C by thermal treatment method. The micrographs HRTEM showed homogenies particle size distribution on high area Vulcan XC-72 Carbon support. The particle size were determined as the maximum of Gaussian distribution of Pt/C; Pd/C e PtxPdy/C which showed electrochemical activity toward ethanol oxidation reaction in both, acid and alkaline, electrolyte. The exception is Pd in acid media. Moreover, the materials Pt75Pd25/C; Pt75(PdOx)25/C; Pt50Pd50/C e Pt50(PdOx)50/C with high Pd content, showed more better performance for ethanol oxidation reaction in alkaline media, with high anodic current density registered in the cyclic voltammetry and chronoamperometry experiments, in comparison with Pd/C e Pt/C catalysts.Item A boniteza da implementação da Lei 10.639/03 no ensino de química esperançando criticamente superar os estigmas étnico-raciais do ambiente escolar(Universidade Federal de Goiás, 2022-06-07) Moreira, Marilene Barcelos; Benite, Anna Maria Canavarro; Benite, Anna Maria Canavarro; Pinheiro, Bárbara Carine Soares; Mesquita, Nyuara Araújo da Silva; Ferraz, Elzimar Pereira Nascimento; Longhin, Sandra ReginaThe Brazilian educational system, which has trained many generations, has been based on traditional, conservative, alienating models that standardize minds and behavior. These models are characteristics inherited from colonization, which for a long time used the dictates of the Eurocentric monoculture, which validates a single and exclusive "scientific knowledge", excluding from the social dynamics, the knowledge of other people from the educational scenario. Unfortunately, these elements have closed our eyes to the asymmetries and social problems present in the classroom. However, the requirements of Law 10.639/03 brought to education our awakening to ethnic-racial relations, while it taught us to build our "being more". Thinking about the statements of bell hooks on anti-racist education, Paulo Freire on liberating education and the pedagogical interventions developed in the CIATA Collective, we built this thesis seeking to answer: "is it possible to teach Chemistry through an elective subject that has elements of the African Diaspora as a context? We developed the elective discipline "Chemistry in the kitchen: food and the African diaspora" in the school unit CEPAE/UFG, being offered in 2019. We know that there are several instructional materials with anti-racist perspectives for science teaching, but we needed one that embraced the triangulation of chemical knowledge and the three Freirian pillars: culturality, politicality and dialogicity. Thus, we developed our instructional material that was offered, in printed form, to 30 high school students in the 2nd and 3rd grade. All classes were recorded and later transcribed, which we reflected upon in the light of Conversation Analysis. From the actions taken, we bring the reflections of two pedagogical interventions, being that of subtheme 03, African diaspora and carbohydrates as a source of energy (with 118 conversational turns) and that of subtheme 09, the African traditional knowledge in the popular pharmacopoeia of the serried as a context in the identification and conceptualization of substances (with 138 conversational turns). We limited the analysis to these two, because we understand that they already bring enough reflections capable of answering the proposed question. In this research, we present the reasons for the implementation of law 10.639/03 in primary and secondary education; the Freirean perspectives for an anti-racist education; and, the chapter that interweaves the teaching of chemistry, food and African and Afro-Brazilian culture. In the unveiling of the plot, we explain the development (planning and elaboration) of the instructional material for each theme, as well as the reflections, supported by the Freirian pillars (which we call circularity) and by theoretical references of the science/teaching of chemistry and anti-racist education. The data aims to show that a collaborative and contextualized teaching with the students' reality can be a possible path to the construction of an anti-racist and liberating education.Item Casos investigativos e a relação com o saber: estreitando laços no ensino de química em nível superior(Universidade Federal de Goiás, 2015-12-16) Francisco, Welington; Benite, Anna Maria Canavarro; http://lattes.cnpq.br/8433607360245647; Benite, Anna Maria Canavarro; http://lattes.cnpq.br/8433607360245647; Lopes, Edinéia Tavares; Machado, Sérgio de Paula; Soares, Márlon Herbert Flora Barbosa; Mesquita, Nyuara Araújo da SilvaThis study presents the application of three-mediated activities that use of investigative cases (IC) as situations for teaching chemistry, which are anchored in the light of the notion of relationship with the knowledge. All the cases were worked in higher education courses at the Federal University of Tocantins - Campus of Gurupi as integral parts of both disciplines. The first IC was applied in the discipline of Fundamentals of Analytical Chemistry and saw the participation of twelve students from the Environmental Chemistry course (EC) and twenty two undergraduate students from Bioprocess and Biotechnology Engineering (BBE), dividing the class in twelve group (G1 to G12). The second and third activity were planned in the course of Instrumental Analytical Chemistry with the participation of sixteen students (S1 to S16) and fourteen students (S1 to S14) of the sixth semester of the EC course, respectively. We make use of participatory research to conduct all activities and the narratives for data collection. The categorization of the paths taken by students during the resolution of the case was realized by content analysis and to analyze the process of learning chemistry was used the notion of relationship with knowledge. The analysis of the narratives allowed: identify and categorize the strategies and actions used by students throughout the activity, as well as unveiling the relations with knowledge that prevail in each category; and list the ways that students take ownership of chemical knowledge present in the cases. Thus, our results indicate that in all activities there was the appropriation of chemical knowledge, whichever the description of phenomena or chemical process whereas the level of ownership among students differs according to the relationship with themselves during the activity. In addition, we observed that the concepts of mobilization, questioning teacher, relationship of knowledge, network of meanings and normativity, present in the notion of relationship with the knowledge, enable to guide, to lead, to block and to support the analysis of the learning process of concepts chemical intrinsic to cases applied.Item Contribuição ao estudo de espécies da família Rubiaceae: gênero amaioua(Universidade Federal de Goiás, 2014-03-07) Oliveira, Pollyanna Laurindo; Oliveira, Cecília Maria Alves; http://lattes.cnpq.br/3152041311943092; Oliveira, Cecília Maria Alves de; Garcez, Walmir Silva; Foglio, Mary Ann; Lião, Luciano Morais; Sabino, José RicardoThe Amaioua genus (Rubiaceae) is included in the subfamily Ixoroideae. The genus comprises 10 species, ranging from Panama to Peru, Venezuela and Brazil, and four of these species are found in Cerrado (DELPRET et al., 2004b). There are no records in the literature on the popular use of the Amaioua genus. Amaioua guianensis Aulb is a shrub up to 3 m or a 10-20 m tree, popularly known as marmelada-brava ou marmelinho-vermelho. Phytochemical studies of leaves and twigs of this species led to the isolation of several classes of secondary metabolites, such as coumarins, a cyclopeptide alkaloid, pentacyclic triterpenes, proanthocyanidins and chlorogenic acids (OLIVEIRA,2009). Amaioua intermedia Mart, popularly known as carvoeiro, pau-carvão, cinzeiro, canela-de-veado, guapeva-forte or marmelada-brava, presents itself as shrubs up to 3 m or 15 m trees. Until the moment there are no records in the literature about a phytochemical study of A. intermedia,. As part of our phytochemical research for new compounds from higher plants, we studied the ethanolic extracts of A. guianensis and A. intermedia, and evaluated the antioxidant activity of such extracts and fractions obtained from them. Herein we describe the isolation and structural elucidation of a new kaurane diterpene (compound 8), a new cyclopeptide alkaloid (compound 19), two new secologanin iridoid (compounds 24 and 25, and seventeen known compounds: a cyclopeptide alkaloid (compound 7), five iridoids (compounds 1, 13, 14, 15 and 16), a ent-kaurane diterpene (compound 22), two dimeric proanthocyanidins (compounds 11 and 12), three pentacyclic triterpenes (compounds 9, 20 and 21), a sugar (compound 10) and four steroids (compounds 3, 4, 5 and 6). The antioxidant activity analysis of the raw extracts obtained from fruits, roots, leaves and twigs of A. guianensis, as well as the raw extracts from the leaves and twigs of A. Intermedia, showed that they reacted to the DPPH radical, leading to a loss of 50% in its absorbance, on the following concentrations of 71.87, 7.55, 5.30, 7.48, 46.83 and 57.42 mg/mL.Item Contribuição ao estudo metabolômico de espécies do gênero Cnidoscolus (Euphorbiaceae) da região do Cerrado e da Caatinga(Universidade Federal de Goiás, 2022-04-06) Martins, Marcos Pereira; Kato, Lucilia; http://lattes.cnpq.br/1362891438631386; Kato, Lucilia; Lião, Luciano Morais; Severino, Vanessa Gisele Pasqualotto; Lemes, Geralda de Fátima; Paiva, Joseilson Alves deThe genus Cnidoscolus belongs to the Euphorbiaceae family, is popularly known as cansanção or favela, and is distributed in several countries in America. In Brazil, this genus is mainly present in the Caatinga phytogeographic domain and has several species widely used by traditional communities. However, there are few chemical and pharmacological studies on this genus and there are no works description involving the annotation of compounds by Molecular Networking. In order to expand the chemical knowledge about the species C. bahianus, C. urniger and C. vitifolius, Nuclear Magnetic Resonance (NMR) and high performance liquid chromatography coupled to electrospray ionization mass spectrometry (HPLC-ESI-MS/MS), principal component analysis (PCA), analyzes were performed involving extracts from leaves and stems, and some metabolites were isolated by filter column chromatography. The antimicrobial activities of C. bahianus, C. urniger and C. vitifolius extracts against Escherichia coli and Staphylococcus aureus strains were evaluated to determine the Minimum Inhibitory Concentration (MIC). The PCA of the 1H NMR data of the extracts revealed that the chemical profile of the species is similar. The analysis of the metabolic classes of the compounds from Cnidoscolus species by HPLC-IES-MS/MS (positive and negative modes) with consequent construction of molecular networking of the studied species led to the dereplication of phenolic compounds with the annotation of 40 flavonoids (class of flavonols, flavanols, flavones and flavanones) and 4 hydroxycinnamic acids. The metabolites isolated by filter chromatography were characterized by NMR as belonging to the steroid class (sitosterol, stigmasterol, campesterol and fucosterol). The ethanolic extract of C. bahianus leaves showed moderate antimicrobial activity and the others showed no activity for the tested strains.Item Contribuição ao estudo químico de espécies da família Cucurbitaceae juss. e Rubiaceae juss. gêneros: Cayaponia Silva Manso e Psychotria L.(Universidade Federal de Goiás, 2015-06-12) Lemes, Geralda de Fátima; Klein, Vera Lúcia Gomes; http://lattes.cnpq.br/6477452328378345; Kato, Lucília; http://lattes.cnpq.br/1362891438631386; Kato, Lucília; Klein, Vera Lúcia Gomes; Paula, Joelma Abadia Marciano de; Ferri, Pedro Henrique; Santos, Suzana da CostaThis work describes the chemical evaluation and, in parallel, the investigation of antioxidant and antimicrobial activity of four medicinal species of Brazilian Cerrado, Cayaponia espelina (Silva Manso) Cogn., C. citrullifolia (Griseb.) Cogn., C. weddellii (Naudin) Gomes-Klein (Cucurbitaceae) and Psychotria trichophora Müll. Arg. (Rubiaceae). The study of ethanol extracts of the species mentioned above led to the isolation of several classes of secondary metabolites, many of them presenting biological activity. Evaluation of ethyl acetate fractions of the leaves of C. espelina and n-butanol and hydromethanol fractions of C. citrullifolia led to the isolation and structural elucidation of seven compounds: luteolin (CE- 1), luteolin 4'-O-glucoside (CE-2), luteolin 7-O-glucoside (CE-3), kaempferol 3,7- O-α-L-dirhamnoside (CC-1), benzyl-O-β-D-xylopyranosyl-(1→6)-β-Dglucopyranoside (CC-4), salicylic acid 2-O-β-glucopyranoside (CC-3) and vicenin-2 (CC-2). The glucosides CE-2 and CE-3 found in C. espelina were also found in ethyl acetate fraction from C. weddellii leaves, indicating that there might be a chemical similarity between these species. The fourth species investigated in this study was P. trichophora and the chemical study of ethyl acetate fraction of its leaves led to the isolation and structural elucidation of six compounds: camelliaside B (PT-3), kaempferol-3-O-α-L-rhamnopyranosyl-(1→6)-[β-Dxylopyranosyl-( 1→2)]-β-D-galactopyranoside (PT-4), kaempferol-3-O-[β-Dxylopyranosyl-( 1→3)-α-L-rhamnopyranosyl-(1→6)]-β-D-galactopyranoside (PT- 5), kaempferol-3-O-robinoside (PT-2) and 3-O-p-coumaroylquinic acid (PT-6). Coumarin scopoletin (PT-1) were identified from its roots. Structural identification of compounds was performed by spectroscopic analysis including IR and 1H and 13C NMR, in one-and two-dimensions. Flavonoids PT-4 and PT-5, previously isolated in the Fabaceae and Leguminosae families, were described for the first time in Rubiaceae. Furthermore, CCDA analysis of acid-base fractions obtained from P. trichophora leaves did not result positive for alkaloids against the Dragendorff reagent. Preliminary tests in Escherichia coli showed that the ethyl acetate fraction from C. espelina presents pharmacological potential, inhibiting 74 % of bacterial growth at a 82 μg/mL concentration. This fraction also exhibited strong antioxidant activity, with IC50 value of 5.40 ± 0.16 μg/ml, being comparable to that of the commercial antioxidant, ascorbic acid. Extracts from C. espelina and C. weddelli were the most promising antioxidants with IC50 values of 131 ± 0.31 and 13.14 ± 0.57 μg/mL, respectively. In preliminary bioassays against Sarcoma 180 tumor cell line, all tested samples presented low activity despite the literature data for antitumor activity of the isolated flavonoids.Item Controle de qualidade de águas potáveis utilizando análise multivariada de imagens(Universidade Federal de Goiás, 2015-12-15) Damasceno, Deangelis; Oliveira, Sérgio Botelho de; http://lattes.cnpq.br/3447406257464639; Oliveira, Anselmo Elcana de; http://lattes.cnpq.br/0369339073291948; Oliveira, Anselmo Elcana de; Coelho, Clarimar José; Soares, Anderson da Silva; Chaves, Andréa Rodrigues; Coltro, Wendell Karlos TomazelliNew digital image based-analytical methodologies are proposed to measure pH, alkalinity, total hardness, calcium hardness, magnesium hardness, chloride, fluorine, and total iron of potable water samples. Multivariate image analysis and partial leastsquares regression were applied to BMP digital images acquired from a CCD-scanner. RGB, HIS, XYZ and YCbCr color spaces and 300 dpi images of 200 μL water samples were employed. This micro volume per sample yielded micro volumes of analytical waste per sample (400.0 μL). PLS root mean square error of prediction (RMSEP) for pH analyses was 0.16. RMSEP values for alkalinity, total hardness, calcium hardness, magnesium hardness, chloride, fluorine, and total iron were 0.03, 1.20, 2.01, 0.07, 0.04, and 0.06 mg L-1, respectively. Analytical figures of merit were computed for all PLS proposed methods. Mean relative errors ranging from 0.20% to 1.33 were found. The proposed methods were validated against standard analytical procedures for water quality control. There were no statistical differences between mean PLS value and the one found using the respective standard procedure (ttest, = 0.05). Precision was found statistically equivalent for pH, alkalinity, chloride, fluoride, and total iron when compared to the related reference method (Ftest, = 0.05). Therefore, the new PLS analytical methods proposed for water control quality can be employed as an alternative to standard methods.Item Coupled electron-nuclear dynamics in inelastic X-ray scattering(Universidade Federal de Goiás, 2016-06-08) Couto, Rafael Carvalho; Guimarães, Freddy Fernandes; http://lattes.cnpq.br/6780812627526129; Guimarães, Freddy Fernandes; http://lattes.cnpq.br/6780812627526129; Norman, Patrick; Kimberg, VictorEsta tese dedicada a estudos tericos e experimentais de espalhamento ressonante inelstico de raios-X (Resonant inelastic X-ray scattering - RIXS) de molculas de monxido de carbono e gua em fase gasosa. Usando estado da arte clculos ab initio de estrutura eletrnica e formalismo de pacotes de onda dependente do tempo, uma anlise completa dos espectros RIXS experimental dos dois sistemas moleculares foi realizada. Na anlise do CO RIXS, fomos capazes de reproduzir o experimento RIXS com excelente preciso, permitindo uma descrio completa dos espectros experimentais. Interferncia entre diferentes canais RIXS correspondentes disperso via orbitais moleculares ortogonais no estado excitado do CO descrito. Com a ajuda do espectro de alta resoluo e simulaes ab initio, mostramos a quebra da aproximao de Born-Oppenheimer na regio onde estados nais de Rydberg acoplam com o estado nal de valncia. Explicamos a formao de uma caracterstica espectral, que foi atribuda a um nico estado em estudos anteriores. Alm disso, atravs da combinao experimento-teoria, aprimoramos o mnimo do potencial do estado excitado de valncia E 1 , juntamente com o constante de acoplamento entre o estado de valncia e dois estados de Rydberg. A m de estudar a gua, desenvolvemos uma nova abordagem terica para descrever molculas triatmicas atravs do formalismo de propagao de pacote de ondas, que reproduz com grande preciso a estrutura vibracional os espectros experimentais RIXS de alta resoluo, permitindo obter importantes concluses. Ns demonstramos que, devido ao acoplamento dos modos vibracionais e anarmonicidade do potencial no estado fundamental e das superfcies de energia potencial do estados excitados, diferentes estados excitados de camada interna em RIXS podem ser usados como portas para sondar diferentes dinmicas de vibrao e para mapear o potencial do estado fundamental usando modos normais de vibrao molecular. O ajuste dos raios-X acima da ressonncia de absoro permite extrair informaes adicionais sobre o potencial do estado fundamental, devido alta excitao vibracional. Substituio isotpica investigada por meio de simulaes tericas e as importantes caractersticas da dinmica nuclear so discutidas, especialmente para o estado excitado de camada interna dissociativo, onde um chamado pico \atmico " formado. Este recurso crucial para explicar a dinmica nuclear em RIXS da gua. Mostramos o forte potencial de experimentos RIXS de alta resoluo combinados IV com simulaes tericas de alto nvel para estudos avanados de estados moleculares altamente excitados, bem como superfcies de energia potencial do estado fundamental, send utilizada como uma tcnica auxiliar para espectroscopia ptica e infra vermelho.Item A crise da eficiência para além do espaço escolar: as influências dos capitais social, cultural e econômico no desempenho escolar de ciências/química(Universidade Federal de Goiás, 2015-09-25) Ribeiro , Eveline Borges Vilela; Benite, Anna Maria Canavarro; http://lattes.cnpq.br/8433607360245647; Benite, Anna Maria Canavarro; Simões, Armando Amorim; Field's, Karla Amâncio Pinto; Amaral, Nelson Cardoso; Mesquita, Nyuara Araújo da SilvaThis thesis is based on Pierre Bourdieu’s theories about scholar reproduction and in a dialectical conception of world. The aim of this research was to analyze how the crisis of efficiency can be understood from analysis of cultural, social and economic capitals and not as a productivity crisis often debated in the literature. To do this, we analyzed if the cultural, social and economic capitals of secondary students affect theirs school achievement in science / chemistry in different scales (global, national and local). For this, on the global scale (using PISA-2009 data) and national (using ENEM-2009 data), evaluated through Quantile Regression, how the cultural, social and economic capital are related to student achievement in science. We also analyzed the partial and combined effect of different capitals on student performance from a partial regression, followed by a path analysis. These analyzes showed us that, regardless of the context, cultural and social capital have a positive relationship with student achievement in science. Economic capital also has a positive relationship with the school achievement of students in science, however, has different slope coefficients for different quantiles. For the national context, we investigated further how the educational institution the student is in (whether state, federal, municipal or private) affects their school achievement in science, for this we proceed with an ANOVA followed by a Planned Comparison Test. These tests indicated that students in federal and private schools have better achievement than those from the municipal and state schools. To justify our results, we research in a local context (in public and private schools of Jataí-GO and Goiânia-GO) how the student's capitals affect their achievement in chemistry. We elaborated and applied a didactic strategy about “waste and physical and chemistry transformations”, a socio-economic-cultural survey and an interview with responsible for those students. In this context, we could deep the discussions that we had realized in global and national context. Our results provided subsides to affirm that the efficiency crisis of school is configured in a context of crisis of capitalist society. The school crisis is multifaceted and it is a mistake condemns only schools and teachers about the learning problems in science because the social, cultural and economic capital of the students can explain some of these achievement issues. The school is in crisis, but the school's crisis is not a crisis of efficiency, is a societal crisis permeated with ideological aspects, as well as other crises that today's society confronts.Item Currículo para o ensino médio em Goiás (1961-2013) na perspectiva do ciclo de políticas: o lugar da Química(Universidade Federal de Goiás, 2021-05-18) Gonçalves, Luciene Pereira da Silva; Mesquita, Nyuara Araújo da Silva; http://lattes.cnpq.br/6971106875143413; Mesquita, Nyuara Araújo da Silva; Pena, Graziele Borges de Oliveira; Lacerda, Nília Oliveira Santos; Mainardes, Jefferson; Soares, Márlon Herbert Flora BarbosaFrom the rescue of the history of curricular educational policies, it is possible to discuss the contexts that gave rise to the curricula, as well as to understand the factors that influenced their structuring. In this way, we seek, in this research, to investigate curriculum policies for Secondary Education in Goiás through the analysis of curricular and normative documents related to the Chemistry curriculum, from the 1960s to the first decade of the 2000s. As an analytical method, we use the cycle of approach policies by Stephen Ball and Richard Bowe (1992), which allows a critical analysis of the trajectory of these policies from their initial formulation to their performance in the context of practice and their effects. The analysis of the data was structured based on approximations with Bourdieu's perspective in view of the relational character of educational policies and elements such as concealment, disputes and agents of the field, which also permeate the discussions on policies and curriculum. From the analysis, some aspects can be evidenced as the political interference in the structuring of the guiding texts of the curricular organization of the state of Goiás in the period in clipping. This denotes that the politicians or agents of this field have the power to regulate other fields in different dimensions, showing the relative autonomy of the educational field. In view of the results found, we reinforce the importance of knowing and analyzing the contexts that permeate the elaboration of educational policies, in the specific case, curricular policies, in order to reflect on the construction of new and other influences in order to discuss the quality of the school we have for the construction of the school we want.Item Desenvolvimento de biossensores enzimáticos utilizando tecidos de fruto de lobeira (Solanum lycocarpum), bainha de guariroba (Sygarus oleracea Becc) e amêndoa de manga (Mangifera indica) aplicados à determinação de paracetamol(Universidade Federal de Goiás, 2019-02-28) Vilela, Ramon Silva; Fernandes, Kátia Flavia; http://lattes.cnpq.br/9737543228759171; Colmati Junior, Flavio; http://lattes.cnpq.br/0231242349462585; Colmati Junior, Flavio; Teixeira, Guilhermina Ferreira; Silva, Valmir Jacinto da; Martins, Tatiana Duque; Severino, Vanessa PasqualottoIn this work, vegetable tissues of lobeira, guariroba and mango that have none economic purpose as a source of enzymes in the construction of enzymatic biosensors and an electrochemical determination method of paracetamol was optimized with the biosensors built. The quantification of paracetamol is of great interest, because due to the indiscriminate use have increased the concentration of it in wastewater and use, which classifies it as an emerging pollutant, which can lead to harms of the health of the general population.