IQ - Instituto de Química
URI Permanente desta comunidade
O Instituto de Química, da Universidade Federal de Goiás, oferece os cursos de: Química e de Engenharia Química.
Navegar
Navegando IQ - Instituto de Química por tipo de documento "Artigo"
Agora exibindo 1 - 20 de 1075
Resultados por página
Opções de Ordenação
Item 1H HR-MAS NMR and S180 cells: metabolite assignment and evaluation of pulse sequence(2014-04) Oliveira, Aline Lima de; Martinelli, Bruno César Barbosa; Liao, Luciano Morais; Pereira, Flávia de Castro; Lacerda, Elisângela de Paula Silveira; Alcantara, Glaucia BrazHigh resolution magic angle spinning 1H nuclear magnetic resonance spectroscopy (HR-MAS NMR) is a useful technique for evaluation of intact cells and tissues. However, optimal NMR parameters are crucial in obtaining reliable results. To identify the key steps for the optimization of HR-MAS NMR parameters, we assessed different pulse sequences and NMR parameters using sarcoma 180 (S180) cells. A complete assignment of the metabolites of S180 is given to assist future studies.Item 1H HRMAS NMR spectroscopy and chemometrics for evaluation of metabolic changes in citrus sinensis caused by xanthomonas axonopodis pv. citri(2012-05) Silva, Lorena Mara Alexandre e; Alves Filho, Elenilson de Godoy; Choze, Rafael; Liao, Luciano Morais; Alcantara, Glaucia BrazXanthomonas axonopodis (Xac) bacterium causes one of the most feared and untreatable diseases in citriculture: citrus canker. To understand the response mechanisms of orange trees when attacked by Xac, leaves and fruits of Citrus sinensis were directly evaluated by HRMAS NMR (high resolution magic angle spinning nuclear magnetic resonance) spectroscopy. This technique allows the analysis of samples without laborious pre-treatments and also allows access to important information about chemical composition of samples. The orange tree leaves and fruit peels investigated in this study demonstrated the biochemical changes caused by Xac. Aided by chemometric analysis, the HRMAS NMR results show relevant changes in amino acids, carbohydrates, organic acids and terpenoids content.Item 2,5-diketopiperazines via intramolecular N-alkylation of Ugi adducts: a contribution to the synthesis, density functional theory study, X-ray characterization, and potential herbicide application(2022) Mendes, Lorena Lessa; Varejão, Jodieh Oliveira Santana; Sousa, José Antonio de; Carneiro, José Walkimar de Mesquita; Valdo, Ana Karoline Silva Mendanha; Martins, Felipe Terra; Ferreira, Bruno Wesley; Barreto, Robert Weingart; Silva, Toshik Iarley da; Kohlhoff, Markus; Pilau, Eduardo Jorge; Varejão, Eduardo Vinícius VieiraTo investigate the herbicidal potential of 2,5-diketopiperazines (2,5-DKPs), we applied a known protocol to produce a series of 2,5-DKPs through intramolecular N-alkylation of Ugi adducts. However, the method was not successful for the cyclization of adducts presenting aromatic rings with some substituents at the ortho position. Results from DFT calculations showed that the presence of voluminous groups at the ortho position of a benzene ring results in destabilization of the transition structure. Lower activation enthalpies for the SN2-type cyclization of Ugi adducts were obtained when bromine, instead of a chlorine anion, is the leaving group, indicating that the activation enthalpy for the cyclization step controls the formation of the 2,5-DKP. Some Ugi adducts and 2,5-DKPs formed crystals with suitable qualities for single-crystal X-ray diffraction data collection. Phytotoxic damage of some 2,5-DKPs on leaves of the weed Euphorbia heterophylla did not differ from those caused by the commercial herbicide diquat.Item 2-(4-iodo-2,5-dimetoxifenil)-N-[(2-metoxifenil)metil]etamina ou 25I-NBOMe: caracterização química de uma designer drug(2016) Santos, Pâmella Ferraz dos; Souza, Lindamara Maria de; Merlo, Bianca Bortolini; Costa, Helber Barcellos da; Tose, Lilian Valadares; Santos, Heloa; Costa, Gabriela Vanini; Machado, Leandro Fernandes; Ortiz, Rafael Scorsatto; Limberger, Renata Pereira; Vaz, Boniek Gontijo; Romão, WandersonDrug trafficking and the introduction of new drugs onto the illicit market are one of the main challenges of the forensic community. In this study, the chemical profile of a new designer drug, 2-(4-iodine-2,5- dimethoxyphenyl)-n-[(2-methoxyphenyl)methyl]etamine or 25I-NBOMe was explored using thin layer chromatography (TLC), ultraviolet-visible spectrophotometry (UV-Vis), attenuated total reflection with Fourier transform infrared spectroscopy(ATRFTIR), gas chromatography mass spectrometry (GC-MS) and electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR MS). First, the TLC technique was effective for identifying spots related to 25C-, 25B- and 25I-NBOMe compounds, all with the same retention factor, Rf ≈ 0.50. No spot was detected for 2,5-dimethoxy-4-bromoamphetamine, 2,5-Dimethoxy-4-chloroamphetamine or lysergic acid diethylamide compounds. ATR-FTIR preserved the physical-chemical properties of the material, whereas GC-MS and ESI-MS showed better analytical selectivity. ESI(+)FT-ICR MS was used to identify the exact mass (m/z 428.1706 for the [M + H]+ ion), molecular formula (M = C18H22INO3), degree of unsaturation (DBE = 8) and the chemical structure (from collision induced dissociation, CID, experiments) of the 25I-NBOMe compound. Furthermore, the ATR-FTIR and CID results suggested the presence of isomers, where a second structure is proposed as an isomer of the 25I-NBOMe molecule.Item 2-(Pyridin-4yl)benzothiazole and Its benzimidazole-analogue: biophysical and in silico studies on their interaction with urease and in vitro anti-Helicobacter pylori activities(2022) Pereira, Camila de Paula; Lyra, Ana Carolina Fradique de; Oliveira, Breno Germano de Freitas; Nascimento, Igor José dos Santos; Silva Júnior, Edeildo Ferreira da; Aquino, Thiago Mendonça de; Sisto, Francesca; Figueiredo, Isis Martins; Martins, Felipe Terra; Modolo, Luzia Valentina; Santos, Josué Carinhanha Caldas; Fátima, Ângelo deIn this study, the interaction between benzothiazole (BTA, concentration of a drug required for 50% inhibition in vitro (IC50) = 0.77 mM) and benzimidazole (BIA, IC50 = 2.14 mM) with urease was quantitatively assessed, using UV-Vis, molecular fluorescence, and circular dichroism. The results showed that both compounds interact with urease by a static fluorescence quenching mechanism with a non-fluorescent complex formation. The main forces responsible for stabilizing the supramolecular complex between BTA and urease were hydrophobic while, for BIA, van der Waals interactions and hydrogen bonds were the main ones. Urease conformation changes due to the interaction process were analyzed by circular dichroism and synchronous fluorescence. Besides, a competitive assay with substrate and inhibitors was used to evaluate the preferential urease site of interaction with BTA and BIA. Our experimental and theoretical studies supported that both, BTA and BIA, are mixed-inhibitors of ureases with a slight preference to the active site of such enzymes. Finally, both BTA and BIA showed to possess anti-Helicobacter pylori (one reference strain and six clinical isolates) activity, presenting minimal inhibitory concentration (MIC) values ranging from 38-150 and 20-164 µM, respectively. The urease inhibitors omeprazole and hydroxyurea showed MIC values in the range of 46-185 µM and 1683-> 3366 µM, respectively.Item 25I-NBOH: a new potent serotonin 5-HT2A receptor agonist identified in blotter paper seizures in Brazil(2017-02-16) Arantes, Luciano Chaves; Ferrari Júnior, Ettore; Souza, Luciano Figueiredo de; Cardoso, Andriele Costa; Alcantara, Thaynara Lino Fernandes; Liao, Luciano Morais; Machado, Yuri; Lordeiro, Rogério Araújo; Coelho Neto, José; Andrade, Ana Flávia Belchior deA new potent serotonin 5-HT2A receptor agonist was identified in blotter papers by several state level forensic laboratories in Brazil. The 25I-NBOH is a labile molecule, which fragments into 2C-I when analyzed by routine seized material screening gas chromatography (GC) methods. GC–mass spectrometry (MS), liquid chromatography–quadrupole time-of-flight-MS, and Fourier transform infrared and nuclear magnetic resonance analyses were performed to complete molecular characterization. Individual doses range from 300 to 1000 lg. Despite its being a potent 5-HT2A receptor agonist, 25I-NBOH is neither registered in the United Nations Office on Drugs and Crime (UNODC) nor classified as a scheduled substance in most countries. Sweden and Brazil seem to be the only countries to control 25I-NBOH. To our knowledge, this is the first scientific report dealing with identification of 25I-NBOH in actual seizures.Item 2D and 3D mixed MII/CuII metal–organic frameworks (M = Ca and Sr) with N,N′-2,6-pyridinebis(oxamate) and oxalate: preparation and magneto-structural study(2018) Fernandes, Tamires Soares; Melo, Wanessa David Canedo; Kalinke, Lucas Hoffmann Greghi; Souza Filho, Renato Rabelo de; Valdo, Ana Karoline Silva Mendanha; Silva, Cameron Capeletti da; Martins, Felipe Terra; Amorós, Pedro; Lloret Pastor, Francesc; Julve Olcina, Miguel; Gomes, Danielle Cangussu de CastroThree heterobimetallic complexes of formula [Ca2Cu3(mpyba)2(2-apyma)(H2O)7]·8.3H2O (1), [Sr2Cu3(mpyba)2(2-apyma)(H2O)8]·11.6H2O (2) and [Sr4.5Cu4(mpyba)4(ox)(H2O)20]·8.5H2O (3) [H4mpyba = N,N′-2,6-pyridinebis(oxamic acid), 2-apyma = 2-(6-aminopyridinyl)oxamate and ox = oxalate] have been synthesized and structurally characterized. Complexes 1 and 2 are isostructural compounds, with tricopper(II) units having mpyba and its hydrolytic product (2-apyma) as ligands. They are interlinked through strontium(II) (1) and calcium(II) (2) ions to afford neutral two-dimensional networks. Two of the copper(II) ions are five-coordinate in distorted square pyramidal (Cu3) and trigonal bipyramidal (Cu1) surroundings, whereas the other (Cu2) is six-coordinate in an elongated octahedral environment. The main difference between their structures, apart from the number of water molecules, resides in the nature of the alkaline earth cation coordinated to the oxamate fragments, Sr2+ (1)/Ca2+ (2), which exhibit eight and seven coordination, respectively. The π–π interactions and an extensive network of hydrogen bonds in 1 and 2 lead to supramolecular 3D structures. The relatively small size of their cavities, in the micropore domain, hinders the inclusion of N2 but allows CO2 adsorption (0.45 and 0.52 mmol g−1 for 1 and 2, respectively). The structure of 3 is made up of [3,3] metallacyclophane-type motifs, having the formula [Cu2(mpyba)2(H2O)2]4−. These act as tetrakis(bidentate) ligands towards the strontium(II) ions (Sr1, Sr2 and Sr3), leading to a sheet-like polymer growing in the bc plane, which extends further along the crystallographic a axis by a bis(chelating) oxalate between the Sr1 atoms. The investigation of the magnetic properties of 1–3 in the temperature range 1.9–300 K shows the occurrence of an overall antiferromagnetic behaviour for 1 and 2 [J12 = J23 = −9.71(2) (1) and −10.81(5) cm−1 (2), with the Hamiltonian being defined as H = −J12S1·S2 − J23S2·S3 + gβH[S1 + S2 + S3], and a ferromagnetic coupling within the dicopper(II) metallacylophane unit of 3 [J = +1.86(1) cm−1 through the Hamiltonian H = −JS1·S2 + gβH(S1 + S2)]. Simple orbital symmetry considerations (1–3) and the spin polarization mechanism (3) account for the observed magnetic properties.Item 3-phenacylideneoxindoles as a new class of antifungal compounds against Paracoccidioides spp(2023-01-20) Silva, Lívia do Carmo; Santos Filho, Raimundo Francisco dos; Oliveira, Amanda Alves de; Martins, Felipe Terra; Cunha, Silvio do Desterro; Soares, Célia Maria de Almeida; Pereira, MaristelaAims: Considering the need to identify new compounds with antifungal action, the activity of five 3-phenacylideneoxindoles compounds was evaluated. Materials & methods: The compounds were synthesized, and their antifungal activity was elucidated through minimum inhibitory concentration tests and interaction assay with other antifungals. Potential targets of compounds were predicted in silico. Results: 3-phenacylideneoxindoles compounds inhibited fungal growth with minimum inhibitory concentration and minimum fungicidal concentration ranging from 3.05 to 12.26 μM. The compounds demonstrated high selectivity index and presented a synergistic effect with itraconazole. In silico prediction revealed the pentafunctional AROM polypeptide, enolase, superoxide dismutase, catalase and kinases as proteins targets of the compound 4a. Conclusion: The results demonstrate that 3-phenacylideneoxindoles is a potential new class of antifungal compounds for paracoccidioidomycosis treatment.Item 3D printed microfluidic mixer for real-time monitoring of organic reactions by direct infusion mass spectrometry(2022) Duarte, Lucas da Costa; Silva, Igor Pereira da; Maciel, Lanaia Ítala Louzeiro; Vaz, Boniek Gontijo; Coltro, Wendell Karlos Tomazelli3D printing is a technology that has revolutionized traditional rapid prototyping methods due to its ability to build microscale structures with customized geometries in a simple, fast, and low-cost way. In this sense, this article describes the development of a microfluidic mixing device to monitor chemical reactions by mass spectrometry (MS). Microfluidic mixers were designed containing 3D serpentine and Y-shaped microchannels, both with a pointed end for facilitating the spray formation. The devices were fabricated entirely by 3D printing with fusion deposition modeling (FDM) technology. As proof-of-concept, micromixers were evaluated through monitoring the Katritzky reaction by injecting simultaneously 2,4,6-triphenylpropyllium (TPP) and amino acid (glycine or alanine) solutions, each through a different reactor inlet. Reaction product was monitored online by MS at different flow rates. Mass spectra showed that the relative abundances of the products obtained with the device containing the 3D serpentine channel were three times greater than those obtained with the Y-channel device due to the turbulence generated by the barriers created inside microchannels. In addition, when compared to the conventional electrospray ionization mass spectrometry (ESI-MS) technique, the 3D serpentine mixer offered better performance measured in relation to the relative abundance values for the reaction products. These results as well as the instrumental simplicity indicate that 3D printed microfluidic mixer is a promising tool for monitoring organic reactions via MS.Item 3D printing of microfluidic devices for paper-assisted direct spray ionization mass spectrometry(2016) Duarte, Lucas da Costa; Carvalho, Thays Colletes de; Lobo Júnior, Eulício de Oliveira; Abdelnur, Patrícia Verardi; Vaz, Boniek Gontijo; Coltro, Wendell Karlos TomazelliThis study describes the use of a 3D printer to fabricate microfluidic devices for direct spray ionization mass spectrometry (DS-MS) assisted by paper tips. The layout of the proposed devices was designed in a three-dimensional model through a computer-aided design system and printed by a fused deposition modeling method using a thermoplastic filament composed of acrylonitrile butadiene styrene deposited layer by layer. The smallest channel width was 400 μm to ensure 3D printing uniformity without any obstruction. For DS-MS studies, microfluidic channels consisted of a single channel connected to a sample reservoir (3 mm diameter). The printed channel was 3 cm long, 500 μm wide and 500 μm deep. Paper tips (0.5 cm long × ca. 0.5 mm wide) were manually cut and inserted into the extremity of the printed channel to facilitate the spray formation. The spray was promoted by the application of 4 kV at the sample reservoir containing 0.1% formic acid prepared in methanol. This organic medium selected for MS experiments has demonstrated great compatibility with the polymeric material employed to create microfluidic chips. 3D printed devices were kept at a distance of 3 mm from the MS entrance. Using glucose solution as the model, the formed spray by the proposed microfluidic device was extremely stable in comparison to traditional paper spray ionization devices for at least 10 min. The analytical feasibility of printed devices for DS-MS was successfully demonstrated by qualitative analysis of ballpoint pen inks, caffeine, xylose and lysozyme. The 3D printer has allowed the fabrication of printed devices at a very low cost ($0.05) within 20 min. Furthermore, 3D printed devices have exhibited significant repeatability and reproducibility, making their reuse possible. Based on the performance of the proposed devices, we believe they can be used in a broad range of bioanalytical applications.Item 4-Fluorobenzaldehyde limonene-based thiosemicarbazone induces apoptosis in PC-3 human prostate cancer cells(2018) Rodrigues, Bruna dos Santos; Marcelino, Renato Ivan de Ávila; Miranda, Polyana Lopes Benfica; Pires, Ludmila Bringel; Oliveira, Cecilia Maria Alves de; Vandresen, Fábio; Silva, Cleuza Conceição da; Valadares, Marize CamposAims: This study evaluated parameters of toxicity and antiproliferative effects of (+)-N(1)-4-fluorobenzaldehyde-N(4)-{1-methyl-1-[(1R)-4-methylcyclohexene-3-il]-ethyl}-thiossemicarbazone (4-FTSC) in PC-3 adenocarcinoma prostate cells. Main methods: Cytotoxicity of 4-FTSC in PC-3 cells was evaluated using MTT assay. Morphology examination of PC-3 cells treated with 4-FTSC was also performed as well as the cell death mechanisms induced were investigated using flow cytometry. Parameters of toxicity of 4-FTSC was conducted by the investigation of its potential myelotoxicity and lymphotoxicity, hemolytic activity and acute oral toxicity profile. Key findings: 4-FTSC showed promising cytotoxic effects against PC-3 cells (IC50 = 18.46 μM). It also triggered apoptotic morphological changes, phosphatidylserine externalization and a significant increase of DNA fragmentation in PC-3 cells. Moreover, 4-FTSC did not show changes in the PC-3 cell cycle with levels of p21, p27, NFĸB and cyclin D1 similar to those found in both control and treated cells. 4-FTSC also promoted an increase of p53 levels associated with mitochondrial impairment through loss of ∆Ψm and ROS overproduction. 4-FTSC-induced cell death mechanism in PC-3 cells involved activation of caspase-3/-7 through apoptosis intrinsic pathway via caspase-9. Regarding toxicological profile, 4-FTSC showed in vitro lymphotoxicity, although with low cytotoxicity for bone marrow progenitors and no hemolytic potential. Moreover, it was classified as GHS category 5 (LD50 > 2000–5000 mg/Kg), suggesting it has low acute oral systemic toxicity. Significance: 4-FTSC seems to be a promising candidate to be used as a clinical tool in prostate cancer treatment. Further studies are required to better clarify its toxicopharmacological effects found in this compound.Item A benzothiadiazole-quinoline hybrid sensor for specific bioimaging and surgery procedures in mice(2021) Medeiros, Gisele Alves; Corrêa, José Raimundo; Andrade, Lorena Pereira de; Lopes, Thiago Oliveira; Oliveira, Heibbe Cristhian Benedito de; Diniz, Ariane Barros; Menezes, Gustavo Batista de; Rodrigues, Marcelo Oliveira; Silveira Neto, Brenno Amaro daThe work describes the design, synthesis, characterization and biological application (bioimaging) of a new hybrid and fluorescent 2,1,3-benzothiadiazole-quinoline sensor. Both photophysical data of the designed compound and DFT calculations have indicated its high stability and have pointed to its possible efficient application as a bioprobe for bioimaging experiments. The new sensor has been designed to display lipophilic character being capable of selectively stain lipid bodies independent whether live and fixed cancer cells were used. The fluorescent sensor has also been tested as a specific bioimaging marker for C. elegans (complex multicellular model) and has showed far better selectivity in the worm than the commercially available BODIPY. A live mice has been submitted to a surgery procedure and the adipocytes (lipid-rich) cells have been differentiated from standard cells. Experiments using high fat fed mice have enabled a high-resolution 3D image reconstruction. Also, in another surgery procedure, hepatocyte cells could have been successfully followed in the blood flow using the designed sensor in a multistaining procedure alongside with a commercially available blue emitting nuclei marker.Item A blue-light-emitting cadmium coordination polymer with 75.4% photoluminescence quantum yield(2019) Nascimento Neto, José Antônio do; Valdo, Ana Karoline Silva Mendanha; Silva, Cameron Capeletti da; Guimarães, Freddy Fernandes; Queiroz Júnior, Luiz Henrique Keng; Maia, Lauro June Queiroz; Santana, Ricardo Costa deWe report a novel bright deep-blue-emitting crystal form based on a simple cadmium coordination polymer with an impressive external photoluminescence quantum yield of 75.4(9)%.Item A comparative study on the crystal structure of bicycle analogues to the natural phytotoxin helminthosporins(2016) Barbosa, Luiz Cláudio de Almeida; Teixeira, Róbson Ricardo; Nogueira, Leonardo Brandão; Maltha, Celia Regina Alvares; Doriguetto, Antonio Carlos; Martins, Felipe TerraHerein we described structural insights of a series of analogues to helminthosporin phytotoxins. The key reaction used to prepare the compounds corresponded to the [3 + 4] cycloaddition between the oxyallyl cation generated from 2,4-dibromopentan-3-one and different furans. Their structures were confirmed upon IR, NMR and X-ray diffraction analyses. While bicycles 7, 8 and 9 crystallize in the centrosymmetric monoclinic space group P21/c, compound 10 was solved in the noncentrosymmetric orthorhombic space group P212121. The solid materials obtained were shown to be racemic crystals (7, 8, 9) or racemic conglomerate (10). In all compounds, there is formation of a bicycle featured by fused tetrahydropyranone and 2,5-dihydrofuran rings. They adopt chair and envelope conformations, respectively. Crystal packing of all compounds is stabilized through C–H•••O contacts. Conformational aspects as well as similarities and differences among the crystal structures of the synthesized analogues are discussed.Item A comparative study on thermal behavior of solid-state light trivalent lanthanide isonicotinates in dynamic dry air and nitrogen atmospheres(2016-02-24) Nunes, Wilhan Donizete Gonçalves; Teixeira, José Augusto; Nascimento, André Luiz Carneiro Soares do; Caires, Flávio Junior; Ionashiro, Elias Yuki; Ionashiro, MassaoCharacterization, thermal stability, and thermal decomposition of light trivalent lanthanide isonicotinates Ln(L)32H2O (Ln = La to Gd, except Pm; L = isonicotinate) were investigated employing simultaneous thermogravimetry and differential scanning calorimetry (TG– DSC), DSC, infrared spectroscopy (FTIR), evolved gas analysis by TG–DSC coupled to FTIR, elemental analysis, and complexometry. The dehydration of these compounds occurs in a single step, and the thermal decomposition of the anhydrous compounds occurs in one or two (air) and two or three steps (N2). The final residues of thermal decomposition were CeO2, Pr6O11, and Ln2O3 (Ln = La, Nd to Gd) in air atmosphere, while in N2 atmosphere the mass loss is still being observed up to 1000 C. The results also provided information concerning the gaseous products evolved during the thermal decomposition in dynamic dry air and nitrogen atmospheres.Item A comparison of harvesting and drying methodologies on fatty acids composition of the green microalga Scenedesmus obliquus(2020) Oliveira, Carlos Yure Barbosa de; Lopes, Rafael Garcia; Cella, Herculano; Menezes, Rafael Silva; Soares, Aline Terra; Antoniosi Filho, Nelson Roberto; Derner, Roberto Bianchini; Freitas, Thayna Lye ViegasHarvesting and drying processes are still obstacles in the microalgae production chain. In this study, a combination of different harvesting and drying methods for Scenedesmus obliquus was proposed. S. obliquus was cultivated in a pond raceway for 15 days until reaching stationary phase. The culture was separated by different harvesting methods (centrifugation and flocculation) and drying methods (freezing, freeze-drying and oven drying), each combination in triplicate. Flocculation did not influence FAME yield of S. obliquus, except when the biomass was dried in an oven. The biomass that was only frozen had the lowest FAME content due to the presence of reactive water in the biomass. In contrast, frozen biomass had higher content of saturated and monosaturated fatty acids; freeze-drying or oven drying caused an enrichment of the polyunsaturated fatty acids content. In conclusion, if the biomass will be used to extract polyunsaturated fatty acids, freeze-drying would be more appropriate. On the other hand, if the purpose of the biomass is to produce biodiesel, the best process would be to just freeze the biomass.Item A constituição do campo científico da química no Brasil e suas derivações para a formação de professores de química(2022-12) Silva, Francisca das Chagas Alves da; Mesquita, Nyuara Araújo da SilvaThe objective of the article is to discuss the power relations and disputes over capital, the power in the field, the hierarchy of areas of knowledge in the Scientific Field of Chemistry (CCQ) and in the constitution of the chemical habitus, glimpsing the role of teaching in this space based on the field theory of Pierre Bourdieu. The contributions of the author are used as a methodological framework based on the praxeological method. The reasons that can explain the structure of the CCQ in Brazil are rooted in the historical tradition in the experimental character confirmed by the structuring of the field, its practices, beliefs and in the division into Technological and Chemistry Teacher Training subfields, which reveals the power relations in this space. The CCQ maintains and reproduces the valorization of research that focuses on the training of teachers in bachelors degree, considered excellent researchers who influence the teaching and training of chemistry teachers. Contemporary studies in the subfield of Chemistry Teacher Training focus on revealing the marks and tensions of the chemical habitus that compromises the identity of the teacher.Item A constituição do subcampo da formação de professores de química e as estratégias de subversão para o seu reconhecimento no campo científico da química(2022) Silva, Francisca das Chagas Alves da; Mesquita, Nyuara Araújo da SilvaConsiderando la lectura analítica a partir de la teoría de los campos formulada por Pierre Bourdieu, centrada en el área de la Enseñanza de la Química y la estructuración del subcampo de la formación de profesores de química (FPQ), en el presente texto abordamos el campo como espacio social desde el punto de vista del campo científico de la química (CCQ), el habitus de los agentes, las posiciones, las disputas, los intereses y las estrategias de subversión establecidas por el subcampo de la FPQ para buscar su espacio en la química. Argumentamos sobre estas diferentes configuraciones desde el punto de vista del subcampo de la FPQ, dominado en el campo de la química, analizando la producción científica en el área de la Enseñanza de la Química y los datos de las plataformas Acácia y Sucupira. En este proceso utilizamos la metodología praxeológica de Bourdieu y su análisis relacional para debatir las estrategias desarrolladas por los agentes del subcampo de la FPQ en el CCQ para configurar su propio capital y establecer un movimiento de reconocimiento del habitus distinto al del propio químico. Entre dichas estrategias destacan la organización de eventos científicos, la producción de revistas en el área de la Enseñanza de la Química, la formación de maestros y doctores en programas de posgrado en los que los agentes buscan la constitución de un capital científico y el espacio para el reconocimiento del subcampo como perteneciente al campo de la química.Item A database for automatic classification of gender in Araucaria angustifolia plants(2021) Martins, Jefferson Gustavo; Oliveira, Luiz Eduardo Soares de; Weingaertner, Daniel; Barison, Andersson; Oliveira, Gerlon de Almeida Ribeiro; Liao, Luciano MoraisForests have been disorderly exploited, and many species are considered endangered. Some initiatives have been taken in order to prevent forests from being destroyed. A good alternative would be to plan a spatial distribution of plants, with higher number of females than males. Determining the gender of seedlings would provide important information for a possible strategy. Another common problem that researchers in this field very often face, in order to perform their experiments, is the lack of a representative database. To overcome this difficulty, we introduce a new database in this work, which is composed of nuclear magnetic resonance of adult Araucaria angustifolia plants. In order to gain better insight into this database, we have tested different strategies and classifiers. A first set of experiments took three classifiers trained to discriminate males from females considering the original database. A second round of experiments applied the genetic algorithm technique to select subsets of attributes based on single-objective and two-objective functions. After analyzing the achieved results, we have also proposed a new strategy based on statistical measures for selecting subsets from the attributes. A comprehensive set of experiments has shown that the proposed selecting strategy has achieved better performances, with an accuracy of 80.3% (AUC = 79.4). We believe that researchers will find this database a useful tool in their work on determining the Araucaria angustifolia gender. On the other hand, the proposed selecting strategy would be useful for reducing the complexity of databases and accelerating the process of building classification models.Item A dupla hélice do DNA: história revisitada à luz da epistemologia kuhniana(2017-12) Mesquita, Nyuara Araújo da Silva; Oliveira Neto, José Firmino de; Oliveira, Aline Prado de; Moraes, Christianne de Lima BorgesThe study of facts and scientific happenings is important ina sense of enabling the comprehension of the development of sciencein different contexts, such as in teaching environments, in distinctlevels, and in research. However, the interpretation of this historicconstruction must take in consideration notions of science thatovercome linear and neutral perspectives on the construction of thescientific production process. Under that perspective, this articleproposes a re-reading of the elaboration movement of DNA’s doublehelix model from Thomas Kuhn’s epistemological input. It is foundthat this is an important context which pervades scientific up bringingand formation in the field of biological science, as well as in primary asin higher education, and that the concepts developed from theelaboration of the double helix model are pivotal for the comprehensionof knowledge related to genetics, cytology, evolution and other topics.In the process of revisiting this historic moment, we have identifiedthe theoretical clashes among researchers from various fields, thecompetition and the consensus as elements which mobilize the searchfor answers in the accomplishment of a new paradigm. In this manner,science’s dynamism proves to be present, rejecting the idea of a plaingiven fact and valuing the process in which knowledge is built. Wepropose that this is a reflection exercise, considering that revisiting the history of science from different epistemological perspectives can fostersubjects new outlooks on a becoming which uncurtains concepts builtin a dynamic way by men and women who, between comings andgoings, give meaning to the phenomena that surround us.