INSTITUTO DE QUÍMICA

URI Permanente desta comunidade

https://repositorio.ufcat.edu.br/handle/tede/12

O Instituto de Geografia é atualmente composto por 03 (três) cursos de graduação: Química - Bacharelado, Química - Licenciatura e Química Industrial e 2 (dois) Programas de pós-graduação stricto sensu: Mestrado em Química e Doutorado em Química. Este Instituto compõem a estrutura da Universidade Federal de Catalão.

Navegar

Agora exibindo 1 - 20 de 79

Síntese e caracterização de CaTiO3 dopado com Tb3+ e Yb3+
(Universidade Federal de Goiás, 2013-07-16) Alvarenga, Lidianne Dias de; Figueiredo, Alberthmeiry Teixeira de; http://lattes.cnpq.br/7026388762536003; Figueiredo, Alberthmeiry Teixeira de; Pontes, Débora da Silva Lima; Godinho Junior, Mário
Crystalline samples of CaTiO3: X with X = Tb or/and Yb were stoichiometrically prepared by the polymeric precursor method. The structure of the doped sample was analyzed by X-ray diffraction measurements. The diffraction pattern showed a single phase perovskite-related type orthorhombic. The X-ray diffraction was used to evaluate order-disorder materials calcined at different temperatures, and to calculate the lattice parameters and crystallite size of the materials. XANES spectra were used to evaluate the local order around the Ti atoms and correlating with pre presence of clusters TiO5-TiO6. The photoluminescent property of the obtained materials was investigated for the powders calcined at different temperatures and observed a greater issue for photoluminescent material heat treated at 500 ° C.
Elucidação estrutural de heterogalactanas parcialmente metiladas obtidas de Grifola frondosa (“Maitake”) e Pleurotus ostreatus (“Shimeji”)
(Universidade Federal de Goiás, 2013-07-18) Oliveira, Gracy Kelly Faria; Ruthes, Andrea Caroline; Carbonero, Elaine Rosechrer; http://lattes.cnpq.br/7136817335979894; Carbonero, Elaine Rosechrer; Silva, Caroline Mellinger da; Severino, Vanessa Gisele P.
Partially methylated heterogalactans were isolated from the fruiting bodies of the medicinal mushroom Pleurotus ostreatus (mannogalactan) and Grifola frondosa (mannofucogalactan), via successive cold aqueous extraction, followed by fractionation through freeze-thawing, precipitation with Fehling solution of soluble material, and dialysis using membranes with different exclusion limits (MWCO 50, 100, and 500 kDa). Their chemical structures were established based on monosaccharide composition, methylation analysis and NMR studies. The mannogalactan (Mw = 50.7 x 103 g.mol-1) had a main chain of (1→6)-linked α-D-galactopyranosyl and 3-O-methyl-α-D-galactopyranosyl units, both of which are partially substituted at O-2 by -D-mannopyranosyl nonreducing ends.The other was a mannofucogalactan (Mw = 15.9 x 103 g.mol-1), which had a similar main-chain, being a part of the galactopyranosyl units substituted at O-2 mainly by 3-O-α-D-mannopyranosyl-α-L-fucopyranosyl groups and in a minor proportion with α-L-Fucp single-unit side chains. Recently, the heterogalactans are also recognized for their relevant biological activities, such as antitumor, immunomodulatory, anti-inflammatory and antinociceptive effects. Thus, the heterogalactans obtained from G.frondosa and P. ostreatus could present itself as a good candidate to be evaluated for its biological potential.
Síntese e caracterização do Sr1-xLaxSnO3
(Universidade Federal de Goiás, 2013-07-19) Mendes, Sara Bambirra; Santos, Maria Rita de Cássia; http://lattes.cnpq.br/2598029192393541; Santos, Maria Rita de Cássia; Pontes, Fenelon Martinho Lima; Godinho Junior, Mário
The study of tin compounds, especially tin compounds containing rare earths as a substituent, has intensified due to their properties with a broad scope, including: electrical properties, and catalytic photoluminescent. In this work were obtained after addition of SrSnO3 with La3+ in mole percentages (1, 5 and 10%). The synthetic method used was the polymeric precursor, which is a viable alternative for obtaining ceramic materials with nanoscale phase and perovskite type structure. The powders were heattreated at 300, 600, 800 and 1000 ° C for 4 hours. The materials were characterized by thermal analysis (TG / DTG), X-ray Diffraction (XRD), absorption spectroscopy in the IR and absorption spectroscopy in the region of the UV-Visible, Scanning Electron Microscopy (SEM-FEG), Analysis surface area (BET) and photoluminescence measurements. The pure samples and with addition of lanthanum present a single phase with perovskite structure. The decrease the amount of carbonate is related to the temperature according to the infrared spectrum an increase in the calcination temperature causes a reduction in the intensity of the peaks relating vibrations carbonate group. Optical gap of the powders was varied between 3.7 to 3.98 eV. The photoluminescent emission of higher intensity for sample of the SrSnO3 with addition of 1% lanthanum calcined at 600 °C.
Síntese e caracterização de hidróxidos e óxidos nanométricos de gadolínio e samário, pelo sistema hidrotérmico assistido por micro – ondas (HTMW)
(Universidade Federal de Goiás, 2013-07-26) Almeida, Maciel Salomão de; Godinho Júnior, Mário; http://lattes.cnpq.br/8364676654739392; Godinho Júnior, Mário; Figueiredo, Alberthmeiry Teixeira de; Barrado, Cristiano Morita
The method of obtaining nanorods was conducted by precipitation of hydroxides of samarium and gadolinium weak base with ammonium hydroxide at room temperature and subsequent calcination of hydroxides to oxides. For the nanosized powders hydroxide with nanorods morphology was used hydrothermal system assisted by microwave (HTMW). The products obtained were characterized by X-ray diffraction, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The application of X-ray diffraction identified crystalline phases, quantitation of phases, determining the parameters of the unit cell, the crystallite size and orientation. The scanning electron microscopy and transmission contributed to the morphological observations in the post hydroxide nanorods. Obtaining oxides occurred after the thermal analysis: Thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The gadolinia and samaria, are known as oxides of these elements were obtained by dehydration of the respective hydroxides. During calcination of the hydroxides, the porosity of the nanorods became increasingly smaller due to reduction of surface free energy of the nanorods, maintaining the morphology.
Estudo químico e avaliação biológica das espécies Byrsonima coccolobifolia Kunth. (malpighiaceae) e Eugenia malaccensis L. (myrtaceae)
(Universidade Federal de Goiás, 2013-07-26) Santos, Marcos Henrique Faleiros; Severino, Vanessa G. Pasqualotto; Severino, Richele Priscila; http://lattes.cnpq.br/8692556857906176; Severino, Richele Priscila; Kato, Lucília; Vieira, Paulo Cézar
The study described in this work contributed to the chemical and biological knowledge of species B. coccolobifoliaand E. malaccensis,known popularly as "murici" and "jambo-vermelho", respectively. These species are found in various regions of Brazil, especially in Cerrado areas, and are widely appreciated by ediblefruit. Several applications in folk medicine are related to these species,such as antibacterial activity, antidiarrheal, anti-inflammatory and on control diabetes (antidiabetic). The study of roots ethanolic extract of B. coccolobifolialed to the identification of mixture of triterpenes α-amiryn and β-amiryn, mixture of steroids campesterol, stigmasterol and β-sitosterol, oleanolic acid(olenene-type triterpene) and glochidonol (lupane-type triterpene), reported for the first time in the Byrsonima genus. Of the leaves ethanolic extract of E. malaccensiswas possible to isolate two flavonoids, mearnsetin and mearnsitrin, both of flavonol class. The structural identification was carried out on the basis of 1D- and 2D-NMR experiments, GC/MS and comparison with literature data. It was also measured the inhibition potential of extracts and your fractions of these plants against cathepsins K, V and L. These enzymes are found mainly in lysosomes and may also involved in selective and controlled pathological processes, such as cardiovascular diseases, osteoporosis, atherosclerosis, malignant, pancreatitis, many others. The extracts and most partitions showed considerable inhibition against cathepsins (concentration of 125 and 50 µg/mL), and the best results are observed for cathepsin V. The flavonoids mearnsetin and mearnsitrin have not presented activity when evaluated in cathepsins K and V (concentration of 25 µM).
Extração seletiva por ponto nuvem para pré-concentração e especiação de arsênio inorgânico em matriz alimentícia empregando espectrometria de absorção atômica eletrotérmica em forno de grafite
(Universidade Federal de Goiás, 2013-07-29) Costa, Bruno Elias dos Santos; Coelho, Luciana Melo; http://lattes.cnpq.br/0074807107314789; Coelho, Luciana Melo; Tarley, César Ricardo Teixeira; Freitas, Sílvia de Sousa
In this study, a highly sensitive and selective procedure for determination of arsenate and total arsenic in rice by electrothermal atomic absorption spectrometry after cloud point extraction As(V)-CPE-GF AAS was developed. The procedure is based on complex formation of As (V) ions with molybdate in the presence of 50.0 mmol L-1 sulfuric acid and 0.1 mmol L-1 ascorbic acid. The complex of As (V)-molybdate was extracted into the surfactant-rich phase of 0.06% w/v Triton X-114 solution. The variables affecting complex formation, extraction and phase separation such as complexing agent concentration, reducing agent concentration and electrolyte concentration were optimized using a factorial design and response surface methodology through central composite design (CCD). Under the optimal experimental conditions, the calibration graph was linear in the range of 0.03 – 10.0 μg L-1 for As (V) ions. The detection and quantification limits for As(V) were 0.0099 and 0.0331 μg L-1 respectively, obtaining an enrichment factor of 78.3 and the corresponding value for relative standard deviation (R.S.D) for 10 replicate determinations was below 5%. A two-level full factorial experimental design involving three factors (permanent modifiers, pyrolysis temperature PT and atomization temperature AT) was investigated to estimate the optimum values of the variables affecting the detection. It was demonstrated that iridium modifier and PT x AT interaction were considered in modeling the response surface. Recovery values were obtained between 90.8% and 113.1% for spiked samples. The method was successfully applied to the determination of As (V) and total arsenic in some rice samples.
Síntese, caracterização e fotoluminescência de titanatos de cálcio dopados com íons Tm³+, Tb³+ e Sm³+
(Universidade Federal de Goiás, 2013-12-06) Rastrelo, Lara Rossana; Figueiredo, Alberthmeiry Teixeira de; http://lattes.cnpq.br/7026388762536003; Figueiredo, Alberthmeiry Teixeira de; http://lattes.cnpq.br/7026388762536003; Machado, Antonio Eduardo da Hora; http://lattes.cnpq.br/3109230347623391; Zampieri, Marcelo; http://lattes.cnpq.br/6834951349421487
The photoluminescent properties (FL) has always aroused the interest of the scientific community, especially after the discovery of photoluminescence at room temperature, which favors applications in new optical-electronic devices. This work used the Polymeric Precursors Method to obtain CTO doped with rare earth ion: Tm3+, Tb3+ and Sm3+. The materials: CTO:Sm1,2%,Tb0,3%,Tm0,5% and CTO:Sm2%,Tb0,3%,Tm0,5% were calcined at temperatures of 450, 500, 550 and 600 ° C in order to correlate structural changes and photoluminescence emission. Other materials: CTO:Sm1,2%,Tm0,5%, CTO:Tm0,5%,Tb0,3%, CTO:Sm1,2%,Tb0,3%, CTO:Sm1,2%Tb0,3%, CTO:Tb0,3%, CTO:Tm0,5%, CTO:Sm1,2% and CTO:Sm2% were calcined at 600 ° C in order to comprehend the influence of rare earth ions in photoluminescence emission process. The structural organization of the materials over long distances CTO:Sm1,2%,Tb0,3%,Tm0,5% was correlated with the emission FL. The FL intensity can be linked directly to the structural system, and the material totally disorganized or completely organized does not present FL emission. The material CTO:Sm1,2%,Tb0,3%,Tm0,5% showed the highest intensity FL to materials heat treated at 500oC, while the material CTO:Sm2%,Tb0,3%,Tm0,5% showed the highest intensity FL to materials heat treated at 450 oC. The electronic transitions from rare earth ions was observed to the obtained materials.
Uma visão da educação ambiental nos projetos de iniciação à docência e na formação de professores
(Universidade Federal de Goiás, 2013-12-20) Santos, Dayane Graciele dos; Nunes, Simara Maria Tavares; http://lattes.cnpq.br/6775966589667074; Nunes, Simara Maria Tavares; Tartuci, Dulcéria; Coelho, Luciana Melo
Currently, many discussions are carried out on the way in which Environmental Education has been approached in school and in school Chemistry and if the teachers are prepared to deal with this theme. Thus, this work proposes to map the sub-project Pibid/Chemistry of the Midwest region, to investigate if they provide and perform actions with environmental dimension and if these have contributed for the formation of environmental educator‟s formation. For this we used qualitative research methodology under the focus of the case study. The data collection was performed by means of the reading of some sub-projects Pibid/Chemistry of the Midwest region and through online questionnaires applied to teachers coordinators and supervisors who participate in the program. For the treatment of the data was used Textual and Discursive Analyze that gave rise to four categories: Actions developed and conceptions of Environmental Education, Environmental Education and relationship with Chemistry education, Didactic strategies of sub projects Pibid/Chemistry of the Midwest region and Contributions of Pibid for initial and continuing education of environmental educators. By the results we realized that even exist several sub-projects Pibid/Chemistry in the Midwest region, there are prevising and development of few actions with environmental dimension. Although the teachers recognize the possibility of contextualization and the interdisciplinary work through the use of environmental themes, the actions described are simple and punctual indicating that there are difficulties in working with the environmental dimension under a critical aspect that would make possible students formation for exercise of citizenship. However, by the reports of the few teachers who work with the environmental dimension is there evidence of the contribution of Pibid for education of environmental educators by the possibility of reflection on the teaching practice. Thus, it is believed that if more sub-projects work with the environmental dimension and were created spaces for reflection of these actions involving coordinators and supervisors teachers, and student of initiation to teaching this program can contribute to the formation of those involved and for the realization of Environmental Education at school and in the discipline of Chemistry.
Seleção e caracterização de aptâmeros de RNA ligantes a regiao 5’-UTR do genoma do virus da dengue
(Universidade Federal de Goiás, 2014-01-21) Cnossen, Elismar de Jesus Nunes; Marangoni, Karina; Neves, Adriana Freitas; http://lattes.cnpq.br/2984939300978146; Neves, Adriana Freitas; Madurro, João Marcos; Santos, Maria Rita de Cássia
The increasing number of notifications of dengue infections is becoming a very important concern for global healthcare programs. Combinatorial technologies aiming the selection of specific short conformational nucleic acid ligands against viral targets, also called aptamers, can be achieved by large-scale selections using the genomic SELEX technology. Our hypothesis is that aptamers can be directly selected against dengue RNA conformational structures that present functional elements in the 5'-UTR sequence, which form RNA-RNA and protein- RNA interactions, and play significant roles in the infection process. Our aim was to select and characterize aptamers that bind to the 5’-UTR using the matrix-free SELEX method. Products from the eighth selection cycle were isolated, cloned and sequenced, and 14 ligands were chosen for in silico characterization. Aptamers were grouped into three families according to their sequence homology, and conserved ribonucleotides generated specific linear motifs. Sequences motifs were detected in random nucleotides regions ranging from 31 to 40 nt, which showed higher affinity to DENV1 and 3 virus. The novel molecules and processes described in this study open new insights for dengue research and applications, and the selected aptamers can be used either as diagnostic or therapeutic tools. In silico analyses revealed that aptamer binding to its RNA target may lead to alterations of viral RNA secondary structures, and is probably leading to the loss of its original conformational and preventing its replication and/or the transcription process. The analyses also demonstrated that aptamers presented a broad hybridization spectrum to DENV1 and 3 even in the presence of mutations in different subtypes, which suggest its possible use in the other two serotypes, DENV2 and 4. This is the first description of aptamers against the RNA structure of Dengue Virus with important implications in the disease control.
O ludo e a ciência dos materiais cerâmicos: construindo conhecimento científico com alunos do ensino fundamental
(Universidade Federal de Goiás, 2014-01-22) Marciano, Eloah da Paixão; Gurgel, Maria Fernanda do Carmo; http://lattes.cnpq.br/1245821448123612; Gurgel, Maria Fernanda do Carmo; Bittar, Thiago Jabur; Santos, Maria Rita de Cássia
This study investigated the lack of interest and motivation of elementary school students across the disciplines of science today, with the justification of instigating and providing innovative solutions to minimize this problem found within the classroom. In this context, research activities and action were performed as school visits and field -Catalan Ceramics for the preparation of the planning, development and execution of the work, thus proposing an alternative methodology using the theme “ceramics” to teach the theoretical and experimental classes in the discipline of science to address content “Soil” dynamic and interactive way. For this purpose, new technologies like data-show, facebook , and educational games were used . Thus , the activities were divided into two stages: The first stage of the design and development work, with bibliographical research in Science Teaching, work in the school - field National College “Dr. Jamil Sebba”, Catalão (GO), with interviews and research profile of the institution , as well as technical visit to the Catalan ceramics, building the theoretical and practical teaching material . And , in the second step, the slide presentation (starting at the theme "Soil", through processing of clay and finishing with traditional and advanced ceramic applications), preparation of educational video about clay modeling, experimental class with modeling clay profile on social networking, business cards and implementation of educational games, which are: Ceramics Trail (traditional game panel) and Ludo Ceramic (virtual game), employed by the site Ludo Education . The audience were 57 students of the National College "Dr. Jamil Sebba", Catalão (GO), mean age 9 to 11 years. These activities enabled satisfactory results, such as the construction of learning from prior knowledge of students on Ceramic Materials; encouraged participation through interactive activities such as lectures and practical use of educational games; promoted interaction and socialization of ideas for discussions in living room and extracurricular using the social network and thus stimulating the active participation of knowledge and interest in science seeking scientific knowledge.
Propriedade fotoluminescente do Ca1-(x+y)YbxTmyTiO3 obtido pelo método hidrotérmico assistido por micro-ondas
(Universidade Federal de Goiás, 2014-01-27) Pereira, Sandra de Cássia; Figueiredo, Alberthmeiry Teixeira de; http://lattes.cnpq.br/7026388762536003
In recent years, the perovskite type oxides doped with rare-earth ions has attracted great interest in the research, especially in the field of photoluminescence (PL). This property has always attracted the interest of the scientific community, especially since their discovery room temperature. The present work aims to study the PL property CaTiO3 (CT) doped with rare-earth ions Yb (III) and Tm (III). Samples of CT pure and doped with rare-earth ions, Ca1-(x+y)YbxTmyTiO3 (x and y = 0, 0,01, 0,0075, 0,005, ou 0,0025 ), were obtained by co-precipitation method and processing using hydrothermal system assisted by microwave , which was used to be a relatively new, promising little used method of processing. The samples were characterized by different techniques, the X-ray diffraction confirmed to obtain a single phase material of orthorhombic perovskite type structure, confirming that the hydrothermal synthesis method is effective in the samples of interest in shorter periods of time. Ultraviolet-visible absorption spectroscopy, allowed calculation of the "gap" optic, confirming the presence of intermediate levels between the valence band and the conduction in the doped samples. The characterization by SEM and EDX confirmed, respectively, obtaining approximately cubic particles and exclusive presence of the cations of interest. PL results show that the doping of CT formation leads of defects to high and low energy in the samples. The highest FL intensity occurs when the doping is performed in proportion to the doping.
Metodologias de preparo de amostras e quantificação de metais pesados em sedimentos do Ribeirão Samambaia, Catalão-GO, empregando Espectrometria de Absorção Atômica
(Universidade Federal de Goiás, 2014-01-27) Mesquita, Glenda Máris; Coelho, Luciana Melo; http://lattes.cnpq.br/0074807107314789; Coelho, Luciana Melo; Eiras, Sebastião de Paula; Andrade, Leonardo Santos
Ensuring water quantity and quality for all human beings has been a very discussed topic nowadays. The River Samambaia, watershed that supplies the city of Catalão, has been suffering with anthropogenic actions and the consequences of human intervention. To evaluate the quality of water may be used: water, particulates and sludge. The sediments can store dangerous substances and then can act as a secondary source of pollution by releasing contaminants into the aquatic environment. Within this context, the aim of this study was to evaluate the potential for contamination and the quality of the River Samambaia, located in Catalão-GO. For this, samples of water and sediment were collected at seven sampling sites along the river and the metals arsenic, cadmium, lead, chromium, manganese and nickel, which are considered toxic, were quantified. Was also performed, on the sampling sites, the analysis of physico-chemical water parameters: pH, conductivity, dissolved oxygen, temperature and salinity. For the extraction of metals fixed in the sediment samples was employed three methods of opening: ultrasound assisted extraction, digestion in digester block and microwave digestion. The quantification of metals was done by Atomic Absorption Spectrometry, by Flame or by Electrothermal Atomization in Graphite Furnace. The three methods opening samples used were effective, but the microwave digestion excelled in all cases. Among the physico-chemical parameters analyzed, pH showed values outside those permitted by law in all sampling points and dissolved oxygen showed the value below allowed only in point 7. In measurements of metals in water samples, cadmium, lead and chromium showed concentrations above the maximum allow by CONAMA. Already for the quantification of metals in the sediment samples, only chromium showed a concentration above the permitted limits. The results presented here indicate that human activities carried out in the river have contributed to adverse effects on local biota and humans.
Desenvolvimento de métodos eletroquímicos para determinação de neurotransmissores utilizando eletrodos de zircônia nanoestruturada e diamante dopado com boro
(Universidade Federal de Goiás, 2014-01-28) Paranhos, Maysa de Melo; Andrade, Leonardo Santos; http://lattes.cnpq.br/5360511377400279; Andrade, Leonardo Santos; Laurindo, Edison Aparecida; Figueiredo, Alberthmeiry Teixeira de
DSA® electrodes modified with films ErYZrO2 or YZrO2 and boron-doped diamond electrodes (BDD) were tested as electrochemical sensors detect front of the neurotransmitter epinephrine and its interfering ascorbic acid (AA) and uric acid (UA), which coexist with epinephrine in biological fluids and are also electroactive, rusting in the same potential that epinephrine. The physical and morphological characterization of the films of ZrO2 were performed using the techniques of XRD, SEM / FEG, EDXS and Open circuit potential. For electrochemical characterization of the sensor in developing were used the techniques of cyclic voltammetry (CV), differential pulse voltammetry (DPV) and Flow Injection Analysis with Amperometric Detection. The analyzes used for physical and morphological characterization of the ZrO2 films demonstrated that the technique of spin coating together with the methodology used for the deposition of ZrO2 films on the surface of substrate DSA® showed films were obtained satisfactory. The BDD electrodes showed good catalytic activity for both analyzed substances (EP, AA and UA). While BDD electrode showed good sensitivity for detection of EP in the presence of AA, electrodes ZrO2 addition to good sensitivity and selectivity showed good reproducibility for the detection of EP without interference from UA and AA.
Estudos de compostos baseado no ligante fenilhidrazonopropanodinitrila para-substituída e seus compostos de coordenação visando sua aplicação em dispositivos ópticos não-lineares
(Universidade Federal de Goiás, 2014-02-07) Caixeta, Bruno Pontes; Romualdo, Lincoln Lucilio; http://lattes.cnpq.br/4703139616158480; Romualdo, Lincoln Lucílio; Machado, Antonio Eduardo da Hora; Gatto, Cláudia Cristina
In this study, the synthesis of five carbonylcyanidephenylhydrazone (ccp), with general formula [RC6H4NHNC(CN)2], where R (= -CH3, -H, -COOH, -CN e -NO2), and their coordination complexes with Ag(I) is presented. Subsequently, these compounds were characterized using spectroscopic methods. The analysis of the compound ccp-H by X Ray diffraction reveals that structurally this compound consists of a nearly linear and planar polymeric form. Data from infrared spectroscopy suggest the formation of hydrogen bonds between the units ccp. In the synthesized Ag(I) coordination compounds, the coordination of each Ag(I) occurs with three ccp units, forming a tridentate ligand-metal coordination with the formation of a three-dimensional structure. In the evaluation of the potential of these compounds to present expressive nonlinear optical properties (NLO), with special attention to the first hyperpolarizability (β), methods from Density Functional Theory (DFT) were employed to describe the structural and electronic characteristics of these compounds, and in the calculation of this parameter. The results show that the incorporation of a group with a strong electron acceptor character, along with the introduction of Ag(I), increases significantly the  values. On the other hand, the results suggest that the CAM-B3LYP functional provides more reliable  values, since the calculations based on this functional reproduced well experimental values of  related to compounds used to calibrate the instrumentation used in these measurements. Based on the estimated  values, it is expected that the studied coordination polymers present promising characteristics for use in photonic devices.
A questão ambiental e o conhecimento químico no ensino médio
(Universidade Federal de Goiás, 2014-02-13) Oliveira, Kátia Martins de; Nunes, Simara Maria Tavares; http://lattes.cnpq.br/6775966589667074; Nunes, Simara Maria Tavares; Coelho, Luciana Melo Lopes; Flores, Maria Marta
Because the believe that Environmental Education plays an important role in the development of knowledge, skills and values so that they can assist in raising the quality of life and in civic education, this paper presents the results of an investigation in which sought to investigate the reality of Environmental Education within disciplines, especially in the discipline of Chemistry, in state schools of the Regional Secretariat of Education of Catalão – Goiás. Therefore, the principal objective of this study was to evaluate and map if are occurring actions with the environmental dimension in schools of this Secretariat. This research was inserted within a qualitative research study and used as tools to collect data the documental analysis and questionnaires. Data collection was performed by the analysis of the articles of the Journal “Química Nova na Escola” and through questionnaires applied to the teachers. For the treatment of data from questionnaires it was used the Discourse Textual Analysis that gave rise to four categories: Importance of Environmental Education and of Chemistry Teaching; Possibilities and challenges for working with Environmental Education, Trends/Conceptions of Environmental Education and Continuing education in Environmental Education. At the conclusion of this project it was offered a workshop of continuing education for teachers and inicial traning students of Chemistry of “Universidade Federal de Goiás – Campus Catalão”, which was entitled “Environmental Issues and Chemical Knowledge at High School and 9th grade of Elementary School”. After the workshop a questionnaire was administered to the participants. From the obtained results it can be seen that there are few studies that address environmental issues in Chemistry teaching. Even, the analyzed articles indicate that most conceptions of Environmental Education are in the most traditional form. This results also demonstrate the existence of gaps and the ausence of contextualization between Environmental Education and Chemistry teaching. It was noted that issues related to environmental theme are unsatisfactory and with low frequency in the documents (Projeto Político Pedagógico – PPP and/or Plano de Desenvolvimento da Escola – PDE), especially with regard to chemistry. The questionnaires revealed that teachers recognize the importance of environmental issues, but it was realized that they have difficulty in incorporating environmental issues into their lessons and break with traditional and conservative practices in everyday school life.
Estudo químico e avaliação do potencial efeito biológico das folhas e flores de Hymenaea stigonocarpa Mart. ex Hayne (Fabaceae)
(Universidade Federal de Goiás, 2014-03-31) Monteiro, Afif Felix; Severino, Vanessa Gisele Pasqualotto; http://lattes.cnpq.br/0286065758729632; Severino, Vanessa Gisele Pasqualotto; Borges, Warley de Souza; Carbonero, Elaine Rosechrer
The Brazilian Savannah is rich in plant species, and that is why it is promising to study natural products (NPs) which can act as sources for the development of new drugs, such as chemotherapeutic and chemopreventive agents, and inhibitors of enzymes such as cathepsins, which are lysosomal proteases with beneficial functions but are also involved in pathological processes (cancer, arthritis, osteoporosis, immune disorders and viral infections). Although these enzymes have been studied as targets for drug development, few inhibitors based on NPs have been described in the literature. In this work the chemical-biological study of Hymenaea stigonocarpa was carried out in the search for potential secondary metabolites capable of inhibiting the activity of cathepsins K, L and V as well as the viability of tumor cells S-180 and Ehrlich. By means of chromatographic techniques, 5 substances were isolated from the leaf extract, which have not been previously reported to H. stigonocarpa: labd-7,13-dien-15-oic acid (I), labd-7-en-15-oic acid (II), ent-Δ13,14-labd-8-β-ol-15-oic acid (III), 4’,5,7-trihydroxy-3’,5-dimethoxyflavone (IV) and p-hydroxybenzoic acid (V), along with one substance obtained from the flower extract, which has not been described in the literature: 18-hydroxy-ent-halima-1(10),13-E-dien-15-oic acid (VI). Therefore, this study has contributed to enrich the knowledge of NPs produced by this species. The diterpenoids I and III were assayed for their cytotoxic potential, showing unsatisfactory IC50 values. However, studies have shown that labdane and halimane diterpenoids possess potent cytotoxic effect and that substance IV, isolated in this work, can be considered to have pronounced anticancer activity, making this species promising in the search for compounds capable of inhibiting tumor cells viability. Compounds I, III, III* (methyl ester of III), IV, V and VI were tested against cathepsins K, L and V. The most significant results were observed for compounds I, IV, V and VI against cathepsin V; I and V against the cathepsin L and I against cathepsin K. The inhibitory potency values of these compounds were determined and the most significant results were observed for compound IV (IC50 = 2.9 and 36.9 mM) against cathepsins V and L, respectively. Literature data have reported significant inhibitory activities for flavonoids against cathepsin K, indicating, together with the results obtained in this work, the need for further studies of H. stigonocarpa in the search for cysteine proteases inhibitors.
Síntese e caracterização de cerâmicas do tipo BZYO e BCGO para uso em células a combustíveis
(Universidade Federal de Goiás, 2014-04-11) Borges, Kellen Cristina Mesquita; Godinho Júnior, Mario; http://lattes.cnpq.br/8364676654739392; Godinho Junior, Mario; Simões, Fábio Ruiz; Santos, Maria Rita de Cássia
The study of the synthesis of materials which have proton conductivity contributes to the production of solid electrolytes protonic conductors, used extensively in the operation of fuel cells. Materials doped barium zirconate yttrium (BZYO) and barium cerate doped with gadolinium (BCGO), were synthesized by the polymeric precursor method, which stands as an effective technique. The synthesized powders were characterized by thermal analysis (TG-DTA), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM / FEG) and Zeta Potential. The sinterability of the powders was observed by dilatometric analysis, followed by XRD, SEM / FEG and density apparent. From the results obtained it was possible to verify the formation of BZYO phase at a temperature of 900 °C/ 2h. A higher dopant concentration (20% Y) promoted the formation of the phase in a temperature 800 °C/ 2h, and the formation of the phase BCGO at 950 °C/ 2h. The crystallite size calculated by Scherrer's equation, ranged from 20,8 to 15,2 nm and 38,2 to 30,5 nm for BZYO and BCGO respectively. This results depends on the amount of dopant and its capacity to form solid solution. The micrographs (SEM/FEG) confirmed the nanometric nature of the material with a spherical morphology. The zeta potential was -23,6 mV and -22,8 mV for BZYO and BCGO, respectively, which demonstrates a good stability in the formation of colloidal dispersions for thin film formation which are of interest for fuel cells. The pads BCGO showed a satisfactory densification (95,1%) at 1550 °C/ 4h, a result that shows its applicability as proton conductive solid electrolyte. For tablets BZYO the densification was lower than BCGO with a result of bulk density of 73,8% at 1600 °C/ 4h. This result shows the need for heat treatment at higher temperatures to obtain a higher densification of the pellets.
Estudo químico de carboidratos isolados do micélio do cogumelo medicinal Grifola frondosa (“Maitake”)
(Universidade Federal de Goiás, 2014-06-26) Silva, Estefânia Viano da; Ruthes, Andrea Caroline; Carbonero, Elaine Rosechrer; http://lattes.cnpq.br/7136817335979894; Carbonero, Elaine Rosechrer; Rosado, Fabio Rogério; Severino, Vanessa Gisele Pasqualotto
The mushrooms have been used as food and medicine for thousands of years. Among them, Grifola frondosa (“Maitake”) may be on the most versatile and promising medicinal mushrooms for use as a dietary supplement. Besides the high nutritional value, they are a good source of compounds such as carbohydrates that can act as biological response modifiers. In this work, β-D-glucans (PSF2-GfM and MRSF2K-GfM fractions) and heteropolysaccharides unusual in the literature (MEPF3CW-GfM and PF2K-GfM fractions) were isolated from the mycelium, grown in solid culture, of the G. frondosa, by successive aqueous and alkaline extractions, followed by fractionation through freeze-thawing, precipitation of soluble material with a Fehling solution, and dialysis using a membrane with an exclusion limit of 1000 kDa. The chemical structures were established based on monossacharide composition, periodate oxidation, methylation analysis, HPSEC-MALLS and NMR studies. The branched β-D-glucans (GLC-GfM) found were similar to those previously described for the fungus, which contains a (13)- linked β-Glcp main-chain, substituted at O-6 by single-unit -Glcp side-chains, on the average of one to every third residues of the backbone, but with different molar masses and water solubility. In adittion, novel heteropolymers were obtained. One was a fucomannogalactan (FMG-GfM), with a molar mass of 175 x 103 g mol-1, was shown to have a main chain of (1→6)-linked α-D-Galp and 3-O-Me-α-DGalp, both of which are partially substituted at O-2, principally, by 3-O-α-D-Manp-α-LFucp groups. The other was a fucoxylomannan (FXM-GfM) (Mw 202 x 103 g.mol-1), which consisted of backbone of (13)-linked α-D-Manp units, totally substituted at O-4 mainly by 4-O-α-L-Fucp-β-D-Xylp disaccharide. Thus, the polymers obtained from Grifola frondosa may could be good candidates for evaluation of its biological effect, considering the results obtained for others similar mushrooms polysaccharides.
Estudo químico de erythroxylum suberosum (erythroxylaceae) frente às catepsinas K, L e V
(Universidade Federal de Goiás, 2014-07-17) Nascimento, Michelle Nauara Gomes do; Severino, Vanessa Gisele Pasqualotto; Severino, Richele Priscila; http://lattes.cnpq.br/8692556857906176; Severino, Richele Priscila; Carbonero, Elaine Rosechrer; Pivatto, Marcos
This work describes the chemical study of E. suberosum, aiming to elucidate structures of secondary metabolites in the leaves, stem and roots. Cathepsins assays were used to evaluate in vitro activity of extracts, fractions and isolated compounds, using fluorogenic substrate ZFR-MCA. These enzymes, also known as lysossomal cysteine peptidases are involved in many physiological processes, and are associated with many pathological conditions. Cathepsins K, L and V are involved in the development of diseases such as osteoporosis, skin cancer and atherosclerosis, respectively. Based on pathological processes in which cathepsins are involved, the search for specific inhibitors can be a new approach for the treatment these diseases. The study of ethanolic extract from leaves led to the identification of four flavonoids belonging to the flavonol class: quercetin and its derivatives 3-O-monoglycosides hyperin and isoquercitrin, and 3-O-diglycosides, ombuin-3-rutinoside, all previously reported for this species. The mixture of flavanols, catechin and epicatechin were isolated from ethanolic extract from roots, besides the fatty ester of sitosterol. The mixture of steroids campesterol, stigmasterol and β-sitosterol were identified from the stem extract. This study also suggests the presence of tropane alkaloids, tropacocaine and nortropacocaine, in the ethanolic extract from leaves of E. suberosum, reported for the first time in this species. In the evaluation for cathepsins K, L and V, the extracts (concentration of 50 mg/mL), showed significant inhibition of all enzymes with percentage inhibition values above 60%. The fractions showed significant activity against cathepsin V and L when evaluated at concentrations of 5 and 50 mg/mL. The quercetin flavonol showed IC50 value of 2.2 ± 0.2 μM against cathepsin V and low affinity for cathepsins K and L (100 μM). This is an important result since literature reports for flavonoids as inhibitors of cathepsin V are quite limited.
Síntese e propriedade fotoluminescente do core-shell Ca(1-x)TiO3:Yb(x)@Ca(1-y)TiO3:Er(y)
(Universidade Federal de Goiás, 2015-02-26) Eduardo, Ariadne Canedo; Figueiredo, Alberthmeiry Teixeira de; http://lattes.cnpq.br/7026388762536003
In recent years, research in the nanocomposites area of core-shell type increased significantly. The core-shell type nanoparticles with photoluminescence properties (PL) attract much attention from the scientific community. Are also of great interest nanoparticles that exhibit the upconversion energy, i.e. they absorbing low energy photons and emission high-energy photons. The present work has as objective nanocomposites synthesis of core-shell type, with CaTiO3 matrix (CT) and doped with rare earth ions Er3+ and Yb3+ in a variety composition and variations, to analysis the photoluminescent properties. The nanoparticles of the core and shell were obtained by the Method of Polymeric Precursors. The samples were characterized by X-ray diffraction (XRD) for structural characterization, and it was found that All samples presented the perovskite structure of the orthorhombic type. The characterization by Transmission Electron Microscopy (TEM) failed to demonstrate the formation of core-shell, requiring analysis by Energy Dispersive X-ray (EDX), which showed the presence of rare earth Er3+ and Yb3+ in the different layers. The UV-Vis gap allowed the calculation of the shell and core samples. The PL emission results were used to relate the thickness of the shell and the intensity of the emission. On the other hand, to study the upconversion energy, core materials showed a higher intensity than in the core-shell; the best intensity in the core-shell was found with doping the core with Yb3+ and Yb3+ with shell and Er3+ suggesting the transfer of energy between the layers.

Navegar

Navegando INSTITUTO DE QUÍMICA por Data de Publicação

Resultados por página

Opções de Ordenação