145 results on '"Maria Helena Araujo"'
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2. FIRST REPORT ON OTOTOXICITY OF MEGLUMINE ANTIMONIATE
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Cláudia Maria Valete-Rosalino, Maria Helena Araujo-Melo, Débora Cristina de Oliveira Bezerra, Renata Oliveira de Barcelos, Vanessa de Melo-Ferreira, Tânia Salgado de Sousa Torraca, Ana Cristina da Costa Martins, João Soares Moreira, Mirian Catherine Melgares Vargas, Frederico Pereira Bom Braga, Mariza de Matos Salgueiro, Maurício Naoto Saheki, and Armando Oliveira Schubach
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Mucocutaneous Leishmaniasis ,Drug Toxicity ,Meglumine antimoniate ,Hearing loss ,Tinnitus ,Dizziness ,Arctic medicine. Tropical medicine ,RC955-962 ,Infectious and parasitic diseases ,RC109-216 - Abstract
Introduction: Pentavalent antimonials are the first drug of choice in the treatment of tegumentary leishmaniasis. Data on ototoxicity related with such drugs is scarcely available in literature, leading us to develop a study on cochleovestibular functions. Case Report: A case of a tegumentary leishmaniasis patient, a 78-year-old man who presented a substantial increase in auditory threshold with tinnitus and severe rotatory dizziness during the treatment with meglumine antimoniate, is reported. These symptoms worsened in two weeks after treatment was interrupted. Conclusion: Dizziness and tinnitus had already been related to meglumine antimoniate. However, this is the first well documented case of cochlear-vestibular toxicity related to meglumine antimoniate.
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- 2014
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3. In Vitro Studies of the Activity of Dithiocarbamate Organoruthenium Complexes against Clinically Relevant Fungal Pathogens
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Claudio L. Donnici, Luciano J. Nogueira, Maria Helena Araujo, Sheila Rodrigues Oliveira, Thais F. F. Magalhães, Miriam T. P. Lopes, Ana Cândida Araújo e Silva, Ana Maria da Costa Ferreira, Cleide V. B. Martins, and Maria A. de Resende Stoianoff
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emerging infectious diseases ,invasive fungal infections ,dinuclear pentakis-dithiocarbamateruthenium complexes ,antifungal susceptibility ,cytotoxicity testing ,Candida spp ,Paracoccidioides brasiliensis ,Cryptococcus neoformans ,Sporothrix schenckii ,Organic chemistry ,QD241-441 - Abstract
The in vitro antifungal activity of nine dirutheniumpentadithiocarbamate complexes C1–C9 was investigated and assessed for its activity against four different fungal species with clinical interest and related to invasive fungal infections (IFIs), such as Candida spp. [C. albicans (two clinical isolates), C. glabrata, C. krusei, C. parapsolisis, C. tropicalis, C.dubliniensis (six clinical isolates)], Paracoccidioides brasiliensis (seven clinical isolates), Cryptococcus neoformans and Sporothrix schenckii. All synthesized complexes C1–C9 and also the free ligands L1–L9 were submitted to in vitro tests against those fungi and the results are very promising, since some of the obtained MIC (minimal inhibitory concentration) values were very low (from 10−6 mol mL−1 to 10−8 mol mL−1) against all investigated clinically relevant fungal pathogens, except for C. glabrata, that the MIC values are close to the ones obtained for fluconazole, the standard antifungal agent tested. Preliminary structure-activity relations (SAR) might be suggested and a strong influence from steric and lipophilic parameters in the antifungal activity can be noticed. Cytotoxicity assays (IC50) showed that the complexes are not as toxic (IC50 values are much higher—30 to 200 fold—than MIC values). These ruthenium complexes are very promising lead compounds for novel antifungal drug development, especially in IFIs, one of most harmful emerging infection diseases (EIDs).
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- 2014
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4. AVALIAÇÃO DA QUALIDADE DO SONO ATRAVÉS DA ACTIGRAFIA EM HIPERTENSOS REFRATÁRIOS.
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Chirlene Santos Souza Moreira, Maria do Carmo V. de Crasto, Denise Duprat Neves, and Maria Helena Araujo-Melo
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Psychology ,BF1-990 ,Consciousness. Cognition ,BF309-499 - Published
- 2015
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5. FATORES DE RISCO PARA APNEIA OBSTRUTIVA DO SONO EM HIPERTENSOS REFRATÁRIOS ADULTOS
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Chirlene Santos Souza Moreira, Maria do Carmo V. de Crasto, Denise Duprat Neves, and Maria Helena Araujo-Melo
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Psychology ,BF1-990 ,Consciousness. Cognition ,BF309-499 - Published
- 2015
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6. Extra virgin coconut oil (Cocos nucifera L.) exerts anti-obesity effect by modulating adiposity and improves hepatic lipid metabolism, leptin and insulin resistance in diet-induced obese rats
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de Vasconcelos, Maria Helena Araújo, Tavares, Renata Leite, Torres Junior, Emanuel Ubaldino, Dorand, Victor Augusto Mathias, Batista, Kamila Sabino, Toscano, Lydiane Tavares, Silva, Alexandre Sergio, de Magalhães Cordeiro, Angela Maria Tribuzy, de Albuquerque Meireles, Bruno Ranieri Lins, da Silva Araujo, Rubens, Alves, Adriano Francisco, and de Souza Aquino, Jailane
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- 2022
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7. Potentially obesogenic diets alter metabolic and neurobehavioural parameters in Wistar rats: a comparison between two dietary models
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Bonfim, Thais Helena Figueirêdo do, Tavares, Renata Leite, de Vasconcelos, Maria Helena Araújo, Gouveia, Mirela, Nunes, Polyana Campos, Soares, Naís Lira, Alves, Raquel Coutinho, de Carvalho, Jader Luciano Pinto, Alves, Adriano Francisco, Pereira, Ramon de Alencar, Cardoso, Glêbia Alexa, Silva, Alexandre Sergio, and Aquino, Jailane de Souza
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- 2021
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8. Interculturalidade e plurilinguismo nos discursos e práticas de educação e formação em contextos pós-coloniais de língua portuguesa
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Maria Helena Araujo e Sa, Carla Maria Ataíde Maciel and Maria Helena Araujo e Sa, Carla Maria Ataíde Maciel
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- 2021
9. Comparison of mean glandular dose values provided by a digital breast tomosynthesis system in Brazil
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Beraldo Oliveira, Bruno, Paixão, Lucas, Donato da Silva, Sabrina, Teixeira, Maria Helena Araújo, and Nogueira, Maria do Socorro
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- 2015
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10. The Chemistry Involved in CO2 Conversion: Challenges and Opportunities
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Maria Helena Araujo, Júlia Rodrigues, Ana Luisa Abrantes Simões, and Sara Silveira Vieira
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General Chemistry - Published
- 2022
11. The Role of Universities in the Development of Plurilingual Repertoires: The Voices of Non-traditional Adult Students
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Ambrósio, Susana, Sá, Maria Helena Araújo e, and Simões, Ana Raquel
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- 2014
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12. Lifelong Learning in Higher Education: The Development of Non-traditional Adult Students’ Plurilingual Repertoires
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Ambrósio, Susana, Sá, Maria Helena Araújo e, and Simões, Ana Raquel
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- 2014
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13. Antibacterial and Cytotoxic Activity of Ruthenium‐ p ‐cymene Complexes with 2‐Methylquinolin‐8‐ol Derivatives
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Sophie Hoenke, Jacqueline A. Takahashi, Lucie Heller, Luiz C. A. Barbosa, Geane Pereira de Oliveira, René Csuk, Renata Diniz, Amalyn Nain-Perez, Maria Helena Araujo, and João Paulo A. Martins
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chemistry.chemical_compound ,p-Cymene ,Chemistry ,Cytotoxic T cell ,chemistry.chemical_element ,General Chemistry ,Cytotoxicity ,Medicinal chemistry ,Ruthenium - Published
- 2021
14. Efficient Catalysis of Phosphate Ester Hydrolysis by Bare Silica
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Carlos A. Amaya Vargas, Adolfo H. Moraes, Ângelo M. L. Denadai, Samara Ben B. B. Bahia, Tiago A. S. Brandão, and Maria Helena Araujo
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chemistry.chemical_compound ,General Energy ,chemistry ,Silica gel ,Polymer chemistry ,Ester hydrolysis ,Physical and Theoretical Chemistry ,Phosphate ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Catalysis - Abstract
This work reports the catalysis of bare silica materials (MCM-41, SBA-15, and silica gel) for the complete hydrolyses of bis(2,4-nitrophenyl)phosphate (BDNPP) and bis(4-nitrophenyl)phosphate (BNPP)...
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- 2020
15. Nitrogen-doped carbonaceous materials obtained by CVD process from mesoporous silica for sulfides oxidation
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Luisa E. Milagre, Tatiana A. Ribeiro-Santos, Maria Helena Araujo, Mateus Carvalho Monteiro de Castro, Vitor Fernandes De Almeida, Sara Silveira Vieira, and Ana Paula C. Teixeira
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Reactive nitrogen ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,Carbon nanotube ,Mesoporous silica ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Nitrogen ,Catalysis ,0104 chemical sciences ,Nanomaterials ,law.invention ,chemistry.chemical_compound ,chemistry ,law ,Pyridine ,0210 nano-technology ,Carbon ,Nuclear chemistry - Abstract
In this work, we describe the synthesis of N doped carbon nanomaterials from mesoporous silica impregnated with iron (10 wt%), using acetonitrile as carbon and nitrogen source by CVD process at 600, 650, 700 and 800 °C. The obtained materials showed a N/C content between 8.3–10.1% and a carbon content between 14 and 31%. Results of TEM, TG, elemental analysis, Raman spectroscopy and XRD showed that higher temperatures synthesis has led to the formation of high content and more organized carbon nanostructures, i.e., carbon nanotubes and bamboo-like structures with higher nitrogen contents in their structure. On the other hand, XPS results showed that the carbon structures obtained at 800 °C have preferential the presence of less reactive nitrogen species, i.e. graphitic nitrogen, while the materials obtained at 600 and 650 °C preferentially have the presence of more reactive nitrogen groups such as pyridine. These materials were used as catalysts for the sulfides oxidation. The type of nitrogen group present in the carbon structure influenced directly the activity of the materials. The catalysts obtained at lower temperatures showed the best kinetics of oxidation sulfides, which was related to the presence of a higher content of more reactive nitrogen groups.
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- 2020
16. Preparation and Photophysical Study of Mono- and Dinuclear Ru(II) Complexes with Phenanthroline and Heteroacene-4,4'-Dicarb(eth)oxylic- 2,2'-Bipyridine
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Clayton M. de Souza, Maria Helena Araujo, Vinicius Cattony-Carpentero, and Claudio Luis Donnici
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General Chemistry - Abstract
Este trabalho descreve a preparacao e os estudos fotofisicos dos complexos [Ru(H 2 dcbpy) 2 (L 1 )](PF 6 ) 2 (1a) , [Ru(Et 2 dcbpy) 2 (L 1 )](PF 6 ) 2 (1b) , [Ru(H 2 dcbpy) 2 (L 2 )](PF 6 ) 2 (2) e [(Et 2 dcbpy) 2 Ru(µ-L 3 )Ru(Et 2 dcbpy) 2 ](PF 6 ) 4 (3) , onde H 2 dcbpy = 4,4'-dicarboxi-2,2'-bipiridina; Et 2 dcbpy = 4,4'-dicarbetoxi-2,2'-bipiridina; L 1 = 1,10-fenantrolino-5,6-diona; L 2 = dipiridina[1,4]dioxino-monofenazina e L 3 = tetrapiridina[1,4]dioxino-difenazina. Os novos complexos 2 e 3 , e os ja conhecidos 1a e 1b , foram completamente caracterizados por tecnicas espectroscopicas e fisico quimicas. Foram realizados os estudos fotofisicos de todos os complexos sintetizados e e notavel a hidrossolubilidade observada e a fluorescencia em todos os solventes utilizados, incluindo a agua, o que indica que podem ser bons candidatos como corantes sensibilizadores para celulas solares (DSSCs).
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- 2020
17. UM ESTUDO SOBRE PLANEJAMENTO FINANCEIRO E ESTRATÉGICO EM UMA PIZZARIA DE GUARAPUAVA/PR
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Aline Moreira Sauer, Maria Helena Araujo, and Fernando Volanin
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- 2022
18. Synthesis of environmentally friendly, magnetic acid-type calix[4]arene catalyst for obtaining Biginelli adducts
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Maria Helena Araujo, José D. Ardisson, Carlos Henrique Callegario Zacchi, Sara Silveira Vieira, and Ângelo de Fátima
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010405 organic chemistry ,Chemistry ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Combinatorial chemistry ,Environmentally friendly ,0104 chemical sciences ,Adduct ,Catalysis ,lcsh:Chemistry ,lcsh:QD1-999 ,Yield (chemistry) ,Microwave irradiation ,human activities ,Fe3o4 nanoparticles - Abstract
An immobilized p-sulfonic acid calix[4]arene was synthesized on the surface of silica-coated Fe3O4 nanoparticles. Due to the combination of the magnetic recovery and the acid properties, it acted as a robust, safe and environmentally friendly catalyst for the one-pot synthesis of Biginelli adducts under microwave irradiation and solvent-free conditions. A series of Biginelli adducts were obtained in moderate to excellent yields, and most importantly, the catalyst could be easily recovered by an external magnet and reused five times without significant loss of catalytic activity (ca. 80% yield for all reuses using 0.64 mol% of the catalyst). Keywords: Fe3O4 nanoparticles, p-sulfonic acid calix[4]arene, Magnetic acid catalyst, Biginelli adducts
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- 2019
19. The Portal de Periódicos CAPES and its Importance for National Scientific Development
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Maria Helena Araujo and David Rodrigues da Rocha
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General Chemistry - Published
- 2022
20. Beyond copper-catalyzed azide-alkyne 1,3-dipolar cycloaddition: Synthesis and mechanism insights
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Guilherme A. M. Jardim, Roberto da Silva Gomes, Renato L. Carvalho, Maria Helena Araujo, and Eufrânio N. da Silva Júnior
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chemistry.chemical_classification ,010405 organic chemistry ,Organic Chemistry ,Alkyne ,chemistry.chemical_element ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Copper ,Combinatorial chemistry ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,chemistry ,Mechanism (philosophy) ,Drug Discovery ,1,3-Dipolar cycloaddition ,Click chemistry ,Copper catalyzed ,Azide - Abstract
The current manuscript describes the catalysts in click chemistry reactions, mechanism insights and use of other metals beyond copper associated with Azide-Alkyne Cycloadditions (AAC). Due to their biological importance and several applications in various areas of science, significant efforts have been devoted to devise robust methods for the synthesis of triazoles. Among these approaches, azide-alkyne cycloadditions strategy has been consolidated as a powerful tool for preparing this class of heterocycles. Herein, click reactions involving catalysis with metals other than copper are presented and critically discussed.
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- 2019
21. Luminescence and positron spectroscopies studies of tris(2,2,6,6-tetramethyl-3,5-heptanedionate) europium(III) and terbium(III) complexes containing 2-pyrrolidone as coligand
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Renata Diniz, Tatiana A. Ribeiro-Santos, Dario Windmöller, W.F. Magalhães, Alex S. Borges, Jeferson G. Da Silva, Maria Helena Araujo, and F. Fulgêncio
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Materials science ,Ligand ,Biophysics ,chemistry.chemical_element ,Terbium ,02 engineering and technology ,General Chemistry ,Crystal structure ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Biochemistry ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Positronium ,chemistry ,Excited state ,Physical chemistry ,Molecule ,0210 nano-technology ,Europium ,Luminescence - Abstract
In this work is reported the synthesis, characterization, luminescent properties and positronium formation yields of europium(III) and terbium(III) complexes of stoichiometric formula Ln(dpm)3(2-pyr), where: Ln = Eu and Tb, dpm = 2,2,6,6-tetramethyl-3,5-heptanedionato (dipivaloylmethanate) ion, a β-diketonate ligand, and 2-pyr = 2-pyrrodilidone, a γ-lactam. The crystal structures were determined by single-crystal X-ray diffraction. The complexes crystallize in the space group Pī with one complex in the asymmetric unit. The Eu(III) and Tb(III) ions are seven-coordinated by six O atoms of three β-diketonate ligands, and one O atom of γ-lactam molecule. We present and discuss experimental intensity parameters of 4f-4f transitions in the Eu(III) complexes under UV excitation. The photoluminescent properties of the complexes depend on the energy positions of the ligand-to-metal charge transfer (LMCT) states. The temperature dependence of the Eu(III) 5D0 relaxation rate of the Eu(III) complexes are presented. Positronium formation in Ln(dpm)3 and Ln(dpm)3(2-pyr) (Ln = Eu and Tb) complexes were investigated. A correlation between the parameters of luminescence and positron annihilation spectroscopies has been observed. The results, which strongly evidence the participation of molecular excited states in the positronium formation, were then discussed in terms of the recently proposed Ps formation mechanism, named cybotactic correlated system kinetic mechanism (CCSKM).
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- 2019
22. Alternance et melange de langues (portugais-francais) chez des adolescents Portugais scolarises en France (Code Switching--Portuguese-French in Portuguese Adolescents Schooled in France).
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Carreira, Maria Helena Araujo
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This study investigated the degree to which Portuguese students (n=100) educated in France switched or mixed languages in a written essay. Subjects were told to express themselves liberally in either or both languages. A linguistic history was also taken for each student. The measures were administered in a French-language school, and instructions were given in French. Both qualitative and quantitative code-switching analyses were performed on the texts. Most students, 71.4%, used exclusively French, and 6.1% used exclusively Portuguese. About 9% used mostly French and about 10% used mostly Portuguese. Just over 3% alternated languages without apparent dominance of either. Alternation of languages was categorized as either lexical or syntactic. Language mixing was much more frequent in Portuguese than in French. Six types of mixing were distinguished, and the relative occurrences of the types in the two languages were assessed. Implications for instruction in a second language are examined. (MSE)
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- 1990
23. Theoretical and experimental spectroscopic investigation of new Eu(III)-FOD complex containing 2-pyrrolidone ligand
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Renata Diniz, Gabriel Silva Santos, Alex S. Borges, Maria Helena Araujo, Jiang Kai, and José Diogo L. Dutra
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Square antiprismatic molecular geometry ,Materials science ,Denticity ,Ligand ,Organic Chemistry ,Infrared spectroscopy ,Catalysis ,Complexometric titration ,Computer Science Applications ,Inorganic Chemistry ,Computational Theory and Mathematics ,Molecule ,Physical chemistry ,Molecular orbital ,Physical and Theoretical Chemistry ,Spectroscopy - Abstract
The preparation and photoluminescent properties of the new [Eu(FOD)3(2-Pyr)2] complex (FOD = 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octadionate; 2-Pyr = 2-pyrrolidone) are reported. The obtained complex was characterized by elemental analysis, complexometric titration using EDTA, infrared spectroscopy, and single-crystal X-ray diffraction studies. The coordination polyhedron of the complex is described as a distorted square antiprismatic with both 2-Pyr monodentate ligands coordinated to Eu(III) via the oxygen atoms, in neutral form, while the three FOD molecules are coordinated in the anionic form. Structural modeling at the PBE1PBE/SVP/MWB52 level of theory provided a geometry in excellent agreement with the one obtained experimentally. Spectroscopy properties such as intensity parameters (Ω2 and Ω4), radiative emission rate (Arad), and chemical partition of Arad for [Eu(FOD)3(2-Pyr)2] and [Eu(FOD)3(H2O)2] were calculated by using the QDC model with help of the semiempirical wavefunctions. The modeling of the ligand-to-metal energy transfer for both complexes was performed, allowing to obtain the theoretical emission quantum yield and to characterize the most relevant molecular orbitals involved.
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- 2021
24. Mobilidade Internacional De Estudantes Do Ensino Superior Na CPLP: Questões De Língua E Cultura
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Maria Helena Araujo e Sa, Paul Feytor Pinto, Susana Pinto, Maria Helena Araujo e Sa, Paul Feytor Pinto, and Susana Pinto
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A mobilidade estudantil é uma das principais estratégias de internacionalização das instituições de ensino superior, as quais têm vindo a investir intensamente em políticas diversas de atração e acolhimento académico. No contexto da Comunidade dos Países de Língua Portuguesa, colocam-se problemáticas específicas e complexas no que diz respeito ao papel da língua portuguesa e das culturas nessa mobilidade, apenas parcialmente relativas à sua natureza de língua pluricêntrica: de que forma a língua portuguesa e as suas variedades regionais e nacionais surgem na mobilidade internacional de estudantes do ensino superior? Que representações das línguas e das variedades das línguas em presença podem ser identificadas? Essas representações apontam para discursos deficitários relativamente à variação ou, em oposição, para um entendimento da língua portuguesa, na sua diversidade intrínseca, como potenciadora de espaços dialógicos e de emergência de outras possibilidades de entender e observar o mundo, as sociedades e o conhecimento? Que desafios e potencialidades surgem do encontro entre diferentes culturas (pedagógicas, académicas, investigativas, epistemológicas …)? Será a heterogeneidade linguístico-cultural e pedagógico-académica considerada uma mais-valia ou um constrangimento? Em que aspetos e com que consequências e implicações individuais, sociais, linguístico-comunicativas e epistemológicas? Estas são algumas das principais questões abordadas neste livro onde se cruzam vozes de estudantes, professores, supervisores e instituições de Angola, Brasil, Moçambique e Portugal.
- Published
- 2023
25. Suplementação nutricional e sua associação com a saúde e a composição corporal de praticantes de musculação
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Deyvison Luz Santos, Carla Viana Dendasck, Jones Souza Moraes, Cícero Augusto Chaves Gomes, Elisângela Cláudia de Medeiros Moreira, Euzébio de Oliveira, Keulle Oliveira da Souza, Maria Helena Araujo, Amanda Alves Fecury, Iracely Rodrigues da Silva, Manoel Samuel da Cruz Neto, Claudio Alberto Gellis de Mattos Dias, and Maria da Conceição Nascimento Pinheiro
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lcsh:Social Sciences ,lcsh:H ,lcsh:LC8-6691 ,lcsh:Special aspects of education ,suplementos nutricionais ,reeducação alimentar ,General Earth and Planetary Sciences ,mudanças antropométricas ,lcsh:Science (General) ,General Environmental Science ,lcsh:Q1-390 - Abstract
O presente estudo de cunho quantitativo, teve como objetivo analisar a suplementação nutricional e a sua relação com a saúde e composição corporal de praticantes de musculação em uma academia da cidade de Castanhal-PA, bem como avaliar as mudanças antropométricas ocasionadas em decorrência da reeducação alimentar dos sujeitos pesquisados. Participaram deste estudo 20 indivíduos, sendo 10 homens e 10 mulheres, com idade entre 20 e 35 anos. Foram aplicados dois questionários recordatários, um sobre como era a alimentação do indivíduo antes de iniciar seu período de treinamento e um sobre sua alimentação após três meses de treinamento, e um terceiro questionário relacionado à suplementação alimentar. Os resultados apontaram melhoras significativas na reeducação alimentar dos sujeitos. Quanto a suplementação alimentar, os suplementos mais consumidos foram os ricos em proteínas (60% dos homens e 83% das mulheres) e aminoácidos ramificados, sendo estes consumidos por 30% dos homens e 67% das mulheres. A maior parte dos suplementos foi consumida por iniciativa própria para 38% dos homens. Os benefícios observados e relatados com a suplementação foram o ganho de força e de massa muscular - em que 50% dos homens e 60% das mulheres apresentaram esses ganhos. Sendo que também uma minoria da amostra relatou alguns efeitos colaterais que foram associados ao suplemento alimentar. Mudanças positivas na antropometria também foram observadas. Conclui-se que existe uma forte relação entre exercícios físicos e mudanças de hábitos alimentares, e a associação com uso de suplementos alimentares.
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- 2020
26. Burnout syndrome in professionals from a basic health unit of macapá,-amapá, Brazil
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Allan Anderson Pereira Moura, Claudio Alberto Gellis de Mattos Dias, Amanda Alves Fecury, João Gonçalves Pingarilho, Felipe Ferreira Pinheiro, Euzébio de Oliveira, Maria Helena Araujo, and Carla Viana Dendasck
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Nursing ,business.industry ,Burnout syndrome ,Medicine ,Health unit ,General Medicine ,business - Abstract
A Sindrome de Burnout (SB) e uma importante patologia na area da Saude do Trabalhador (ST), marcada por uma resposta psicossocial inerente
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- 2018
27. Phosphate ester cleavage by a positively charged porous silica adorned with lanthanum (III)
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Carlos A. Amaya Vargas, Ângelo M. L. Denadai, Tiago A. S. Brandão, Joel I. dos Santos, Clésia C. Nascentes, and Maria Helena Araujo
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Reaction mechanism ,Induction period ,Supramolecular chemistry ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Phosphate ,01 natural sciences ,0104 chemical sciences ,Catalysis ,Ion ,Hydrolysis ,chemistry.chemical_compound ,chemistry ,Mechanics of Materials ,Polymer chemistry ,Lanthanum ,General Materials Science ,0210 nano-technology - Abstract
Phosphate esters and analogs thereof are well known in chemistry and biology by their formidable stability. We used a porous silica material (PSiM) functionalized with amino groups (8.4%) and lanthanum ions (1.5%) to catalyze the cleavage of bis(2,4-dinitrophenyl)phosphate (BDNPP). The functionalized PSiM attracted the substrate from solution and accelerated its hydrolysis by 38-fold in relation to the uncatalyzed reaction at pH 8.14. After an induction period associated to hydration of the catalyst during the first use, the catalytic activity increased in the first reuse to about 600-fold. Supramolecular effects were proposed to drive the catalytic process. Kinetic studies in different pH's showed that the lanthanum ion and amino groups acted mutually in the BDNPP hydrolysis and a reaction mechanism that took this into account was proposed.
- Published
- 2018
28. Use of iron mining tailings from dams for carbon nanotubes synthesis in fluidized bed for 17α-ethinylestradiol removal
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Rayane Cristian Ferreira Silva, José D. Ardisson, Ana Paula C. Teixeira, Maria Helena Araujo, and Alexandre A. C. Cotta
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Materials science ,010504 meteorology & atmospheric sciences ,Health, Toxicology and Mutagenesis ,Iron ,Chemical vapor deposition ,Carbon nanotube ,010501 environmental sciences ,Toxicology ,Ethinyl Estradiol ,01 natural sciences ,Mining ,Catalysis ,law.invention ,Adsorption ,law ,Freundlich equation ,Graphite ,0105 earth and related environmental sciences ,Nanotubes, Carbon ,General Medicine ,Pollution ,Tailings ,Chemical engineering ,Models, Chemical ,Fluidized bed - Abstract
This work reports the use of an iron ore tailings from waste dam as a catalyst and support for carbon nanotubes synthesis and their application in the adsorption of the 17α-ethinylestradiol hormone. The synthesis was carried out by Chemical Vapor Deposition (CVD) in a Fluidized Bed system using: ethylene at temperatures of 500, 600 and 700 °C, and acetonitrile at 500, 600, 700, 800 and 900 °C. The transmission electron microscopy (TEM) results showed that the two higher temperatures in each case favored the formation of nanostructures like carbon nanotubes (CNTs), with good yields. The ethylene source generated classic tubular structures of multiple walls. On the other hand, acetonitrile provided the formation of tubes with less organization, known as bamboo like. This morphology was caused by the insertion of nitrogen into the graphite structure (doping), which originates from the carbon source. The adsorptive capacity of the materials for 17α-Ethinylestradiol removal ranging from 9.2 mg g−1 to 22.3 mg g−1. The kinetic and adsorption isotherm studies were also performed for the systems. As for kinetics, all of them presented pseudo-second order behavior. In relation to the type of isotherm, the systems showed Freundlich behavior, that is, the adsorption occurs in multiple layers. Finally, it was concluded that the use of an iron ore tail as a catalyst in the production of CNTs by CVD is feasible. The materials synthesized still had good adsorptive capacity for an emerging contaminant, thus this study allowed the investigation of two environmental problems.
- Published
- 2019
29. NiMo/C Used as Magnetic Support for SILP Catalysts
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Eduardo N. dos Santos, Raquel V. Mambrini, Maria Helena Araujo, Flávia C.C. Moura, and Evelisy C. O. Nassor
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Thermogravimetric analysis ,Tetrafluoroborate ,Materials science ,Polymers and Plastics ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Catalysis ,Nitrobenzene ,Nickel ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Molybdenum ,Ionic liquid ,Materials Chemistry ,Magnetic nanoparticles ,0210 nano-technology - Abstract
In this work, supported ionic liquid (IL) phases catalysts were prepared based on Pd dispersed in IL phases supported on magnetic particles of nickel/molybdenum covered with carbon (NiMo/C). The magnetic support was prepared via CVD method at 800 °C. XRD analysis showed the phases of metallic nickel and molybdenum carbide. The presence of carbon in these materials was confirmed by TEM/EDS and thermogravimetric analysis (TG) analysis. Pd particles were dispersed in 1 and 2.5 wt% of the IL 1-butyl-3-methylimidazolium tetrafluoroborate (BMIm·BF4), which were immobilized on the support surface via impregnation method. TG analysis shows a weight loss between 300 and 420 °C attributed to the BMIm·BF4, confirming the existence of IL on the support surface. The prepared materials were investigated in hydrogenations reactions of 1,5-cyclooctadiene and nitrobenzene, and the influence of IL on the activity and selectivity of these catalysts were observed. These materials have great potential for catalysis applications, because they bring together the advantages of the IL in the catalyst surface and the facility of magnetic materials separation.
- Published
- 2018
30. Papilionoideae of an Area of Vegetation in Northeast from Brazil
- Author
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Gustavo da Silva Gomes, Domingos Lucas dos Santos Silva, Paula Regina Pereira Martins, Guilherme Sousa da Silva, Maria Helena Araujo, Gonçalo Mendes da Conceição, and Regigláucia Rodrigues de Oliveira
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Geography ,medicine ,Forestry ,General Medicine ,medicine.symptom ,Vegetation (pathology) - Published
- 2018
31. Proyecto Escuelas bilingües e interculturales de frontera (PEBIF): un proyecto transfronterizo e integrador en la Península Ibérica
- Author
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María Matesanz del Barrio, Viviane Ferreira Martins, and Maria Helena Araújo e Sá
- Subjects
frontera ,bi-/plurilingüismo ,interculturalidad ,intercomprensión ,escuela de frontera ,Education (General) ,L7-991 - Abstract
La internacionalización de la educación es uno de los objetivos prioritarios de las instituciones educativas porque se considera de importancia estratégica para su desarrollo y proyección. Sin embargo, este concepto no permite describir de forma adecuada la colaboración que se produce en materia educativa entre países vecinos, en particular en las zonas de frontera en las que esa cooperación permite intercambios constantes, experiencias profesionales compartidas, actividades conjuntas, colaboraciones transfronterizas. La frontera entre España y Portugal reúne estas características. El Proyecto Escuelas Bilingües e interculturales de Frontera/ Projeto Escolas Bilingues e Interculturais de Fronteira (PEBIF) es una propuesta que busca una educación intercultural apoyada en el bi-/plurilingüismo y la intercomprensión. El objetivo general del proyecto es promover la cooperación entre España y Portugal en el desarrollo educativo, social y económico de los territorios de frontera a través de la creación de una red de escuelas que proporcione a las poblaciones conocimientos y habilidades asociadas al bilingüismo y la interculturalidad relevantes para la ciudadanía, la continuación de los estudios y la empleabilidad en ambos países. En este artículo se presenta el proyecto PEBIF, tantos sus principios teóricos estructurantes como la implementación realizada, así como los resultados más relevantes obtenidos hasta ahora
- Published
- 2023
- Full Text
- View/download PDF
32. Micromesoporous Activated Carbons as Catalysts for the Efficient Oxidation of Aqueous Sulfide
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Igor Cunha, Manuel Martínez Escandell, João Paulo de Mesquita, Rochel Montero Lago, Fernanda Gomes de Mendonça, Maria Helena Araujo, Rodinei Augusti, Mateus Carvalho Monteiro de Castro, Miguel Molina Sabio, Francisco Rodríguez Reinoso, Universidad de Alicante. Departamento de Química Inorgánica, Universidad de Alicante. Instituto Universitario de Materiales, and Materiales Avanzados
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Sulfide ,Efficient oxidation ,Inorganic chemistry ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Micromesoporous ,Catalysis ,Electrochemistry ,medicine ,General Materials Science ,Porosity ,Spectroscopy ,Activated carbons ,chemistry.chemical_classification ,Química Inorgánica ,Aqueous solution ,Catalysts ,Aqueous sulfide ,Mesophase ,Surfaces and Interfaces ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Sulfur ,0104 chemical sciences ,chemistry ,0210 nano-technology ,Carbon ,Activated carbon ,medicine.drug - Abstract
KOH activation of a mesophase pitch produces very efficient carbons for the removal of sulfide in aqueous solution, increasing the sulfur oxidation rate with the degree of activation of the carbon. These carbons are characterized by their graphitic structures, with domains of sizes of around 20 nm, and a moderate concentration of surface oxygen groups (0.2–0.5 mmol·g–1) dominating the basic groups. Because the activation leads first to a strong development of the micropores and later to a development of the mesopores, the surface area values are always high, reaching values of as high as 3250 m2·g–1 in the most activated carbon, with a volume of mesopores of as high as 44% of the total pore volume. In the presence of this carbon, the sulfide oxidation rate is 100 times higher than that found for a commercial activated carbon, the results indicating that the porosity of the carbon, especially mesoporosity, plays a role more important than the structure or the chemical nature of the carbon in the kinetics of sulfide oxidation to different polysulfides. The authors thank CNPq, CAPES, INCT, PRPq-UFMG, and Prometeo II/2014/004 for financial support.
- Published
- 2017
33. Conversion of fatty acids into hydrocarbon fuels based on a sodium carboxylate intermediate
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Patterson P. de Souza, Maria Helena Araujo, Deise Morone Perígolo, Marcelo Gonçalves Rosmaninho, Rochel Montero Lago, and Fabiano Gomes Ferreira de Paula
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chemistry.chemical_classification ,Sodium oxide ,020209 energy ,Inorganic chemistry ,Thermal decomposition ,02 engineering and technology ,General Chemistry ,Fuels ,Free fatty acids ,021001 nanoscience & nanotechnology ,Sodium hydroxide ,Catalysis ,chemistry.chemical_compound ,Hydrocarbon ,chemistry ,Propane ,0202 electrical engineering, electronic engineering, information engineering ,Carboxylate ,Dehydrogenation ,0210 nano-technology - Abstract
In this work, it was investigated the conversion of fatty acids into hydrocarbon based on the reaction with NaOH followed by a controlled thermal decomposition. FTIR, Raman, UV–vis, XRD, TG-MS, SEM/TEM, CHN, GC–MS showed that precursors based on NaOH/oleic acid (molar ratios 0.7, 1.0, 1.5 and 2.0) decomposed at 550 °C to produce three fractions, i.e. liquid (5–37 wt%), gas (52–70 wt%) and solid (10–31 wt%). The liquid fraction was composed of a complex mixture containing mainly aromatic compounds. On the other hand, the major gas fraction showed a remarkable selectivity for propane (56–61 wt%) with some C 1 , C 2 , C 4 , H 2 and CO x . The solid fraction showed the presence of Na 2 CO 3 , Na 2 O and particles of amorphous and graphene like carbon. Upon treatment at 800 °C the carbonate decomposes to CO 2 , oxidizes the carbon and regenerated the Na 2 O which can potentially be used for a new reaction cycle. These results are preliminary discussed in terms of a catalytic effect of the basic sodium oxide to promote cracking, dehydrogenation and H-transfer reactions.
- Published
- 2017
34. Cyclometalated ruthenium complexes from naturally occurring quinones: studies on their photophysical features, computational details and trypanocidal activity
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Hélio A. Duarte, Rafaela C. Silva, Cynthia Demicheli, Rubem F. S. Menna-Barreto, Carlos A. de Simone, Philipe de Oliveira Fernandes, Solange L. de Castro, José Dias de Souza Filho, Eufrânio N. da Silva Júnior, Maria Helena Araujo, and Clayton M. de Souza
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010405 organic chemistry ,chemistry.chemical_element ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Catalysis ,0104 chemical sciences ,Lawsone ,Ruthenium ,chemistry.chemical_compound ,chemistry ,Materials Chemistry ,Organic chemistry ,Trypanocidal Drugs ,Ruthenium Compounds ,Lapachol - Abstract
Phenazinic ligands and Ru(II)-based complexes were synthesized from natural products lapachol and lawsone and evaluated against T. cruzi, the etiological agent of Chagas disease. These new ruthenium compounds could provide promising trypanocidal drugs. Besides synthesis and trypanocidal activity, this paper reports photophysical features and computational details of the compounds. The fluorescent trypanocidal substances are promising derivatives for further studies aiming to find molecules active against parasites associated with neglected diseases.
- Published
- 2017
35. Effects of AC magnetic field and carboxymethyldextran-coated magnetite nanoparticles on mice peritoneal cells
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Guedes, Maria Helena Araújo, Sadeghiani, Neda, Peixoto, Danielle Lima Guedes, Coelho, Júlia Poubel, Barbosa, Luzirlane Santos, Azevedo, Ricardo Bentes, Kückelhaus, Selma, Da Silva, Maria de Fátima, Morais, Paulo César, and Lacava, Zulmira Guerrero Marques
- Published
- 2005
- Full Text
- View/download PDF
36. Tailings from Fundão Tragedy: Physical-Chemical Properties of the Material That Remains by Candonga Dam
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Maria Helena Araujo, Fernando Soares Lameiras, Ana Paula C. Teixeira, José D. Ardisson, and Marina Duarte Figueiredo
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010504 meteorology & atmospheric sciences ,Injury control ,Accident prevention ,Geography, Planning and Development ,Poison control ,010501 environmental sciences ,01 natural sciences ,Mining ,Disasters ,Mining engineering ,Rivers ,Hydroelectricity ,Physical chemical ,Organic matter ,0105 earth and related environmental sciences ,General Environmental Science ,chemistry.chemical_classification ,General Medicine ,Hematite ,Tailings ,chemistry ,visual_art ,visual_art.visual_art_medium ,Environmental science ,Brazil ,Environmental Monitoring - Abstract
In this work, samples of Fe mining tailings from the collapsed Fundão Dam, Brazil, which were retained by the Candonga hydroelectric power plant, were characterized by various techniques. Quartz, hematite, kaolinite, and goethite were identified as the main phases present. The composition, homogeneity, and relatively low (~1%) organic matter content indicate potential for usage of these tailings in civil constructions. The next step of this work is to investigate such applications. If their feasibility is confirmed, the goal is to use this material for construction in the areas affected by the Fundão Dam rupture. This use will lead to positive socio-environmental impacts in these regions, where tailings still need to be removed and damaged infrastructure needs to be repaired. Integr Environ Assess Manag 2020;16:636-642. © 2019 SETAC.Neste trabalho, amostras do rejeito de mineração de ferro, proveniente do rompimento da barragem de Fundão e retidas pela usina hidroelétrica de Candonga, foram caracterizadas por diversas técnicas. Quartzo, hematita, caulinita e ghoetita foram identificadas como as principais fases presentes no rejeito. A composição, homogeneidade e teor de matéria orgânica relativamente baixo, cerca de 1%, indicam uso potencial deste material em construção civil. O próximo passo deste trabalho é investigar tais aplicações. Se a viabilidade for confirmada, o objetivo é utilizar esse material para obras nas áreas afetadas pelo rompimento da barragem de Fundão. Isso contribuirá para reduzir os impactos socioambientais nessas regiões, as quais ainda necessitam da remoção do rejeito e de reparos na infraestrutura danificada. Integr Environ Assess Manag 2020;16:636-642.
- Published
- 2019
37. Luminescence and positron spectroscopies studies of Eu3+ complexes containing tris(2,2,6,6-tetramethyl-3,5-heptanedionate) and 2-pyrrolidone as ligands
- Author
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W.F. Magalhães, F. Fulgêncio, Alex S. Borges, Jeferson G. Da Silva, Tatiana Ribeiro, Maria Helena Araujo, Renata Diniz, and Dario Windmöller
- Subjects
Materials science ,Positron ,Excited state ,Intramolecular force ,Annihilation radiation ,Physical chemistry ,Luminescence ,Spectroscopy ,Positronium ,Doppler broadening - Abstract
This work is reports the luminescent properties and positronium formation yields of the Eu(dpm)3 and Eu(dpm)3(2-pyr) complexes, where dpm = 2,2,6,6-tetramethyl-3,5-heptanedionato (dipivaloylmethanate) ion and 2-pyr = 2-pyrrodilidone. We present and discuss experimental intensity parameters of 4f-4f transitions in the Eu3+ complexes under UV excitation. Positron annihilation lifetime spectroscopy (PALS) and Doppler broadening of annihilation radiation lineshape (DBARL) measurements were also performed. It was observed that the photoluminescent properties and Ps formation yields of the complexes are related to intramolecular processes, such as a ligand-to-metal charge transfer (LMCT). The results, which strongly evidence the participation of molecular excited states in the positronium formation, were then discussed in terms of the recently proposed Ps formation mechanism, named cybotactic correlated system kinetic mechanism (CCSKM).This work is reports the luminescent properties and positronium formation yields of the Eu(dpm)3 and Eu(dpm)3(2-pyr) complexes, where dpm = 2,2,6,6-tetramethyl-3,5-heptanedionato (dipivaloylmethanate) ion and 2-pyr = 2-pyrrodilidone. We present and discuss experimental intensity parameters of 4f-4f transitions in the Eu3+ complexes under UV excitation. Positron annihilation lifetime spectroscopy (PALS) and Doppler broadening of annihilation radiation lineshape (DBARL) measurements were also performed. It was observed that the photoluminescent properties and Ps formation yields of the complexes are related to intramolecular processes, such as a ligand-to-metal charge transfer (LMCT). The results, which strongly evidence the participation of molecular excited states in the positronium formation, were then discussed in terms of the recently proposed Ps formation mechanism, named cybotactic correlated system kinetic mechanism (CCSKM).
- Published
- 2019
38. Evidences of the participation of excited states in the positronium formation mechanism in Sm1-xEux(dpm)3 and Gd1-xEux(dpm)3 solid solutions
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Antônio Marques-Netto, Sidney. J. Ribeiro, W.F. Magalhães, F. Fulgêncio, Alex S. Borges, Maria Helena Araujo, Rafael Miguel Sábio, Fernando C. de Oliveira, José C. Machado, and Dario Windmöller
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Materials science ,Excited state ,Physical chemistry ,Mechanism (sociology) ,Solid solution ,Positronium - Published
- 2019
39. Geopolymers produced with fly ash and rice husk ash applied to CO2 capture
- Author
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Agenor De Noni Junior, Andreia De Rossi, Maria Helena Araujo, Enrique Rodríguez Castellón, Regina de Fátima Peralta Muniz Moreira, Alírio E. Rodrigues, Camilla Daniela Moura-Nickel, Gidiane Scaratti, and Alisson Lopes Freire
- Subjects
Cement ,Materials science ,Renewable Energy, Sustainability and the Environment ,Scanning electron microscope ,020209 energy ,Strategy and Management ,05 social sciences ,02 engineering and technology ,Husk ,Industrial and Manufacturing Engineering ,law.invention ,Geopolymer ,Adsorption ,Compressive strength ,Chemical engineering ,law ,Fly ash ,050501 criminology ,0202 electrical engineering, electronic engineering, information engineering ,Calcination ,0505 law ,General Environmental Science - Abstract
The cement normally applied in carbon capture and storage sites as well lining or plugs may undergo degradation due to carbon dioxide (CO2) exposure, increasing the risk of CO2 gas leakage to the surface. Thus, finding a substitute is urgently necessary. This study reports the application of geopolymers produced with fly ash and rice husk ash as an adsorbent material for the capture of CO2. Different geopolymer formulations were used to produce mechanical resistance and CO2 adsorption capacity materials. The quantification of the reactive oxides in the precursor materials was carried out to obtain a better degree of geopolymerization. The geopolymers were characterized by X-ray diffraction (XRD), Brunauer - Emmett – Teller (BET), Scanning electron microscopy (SEM) and compressive strength analysis. Calcined rice husk ash activated by NaOH was found to be the most suitable precursor material to produce a geopolymer for CO2 adsorption, with a capacity 24.4% higher than the best geopolymer adsorbent reported in the literature to date.
- Published
- 2020
40. Self-reporting of hearing loss and tinnitus in the diagnosis of ototoxicity by meglumine antimoniate in patients treated for American tegumentary Leishmaniasis
- Author
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Claudia Cristina Jardim Duarte, Tania Salgado de Sousa Torraca, Débora de Oliveira Bezerra, Renata de Barcelos Oliveira, Nayany Kerollyany Sousa Leite, Raquel de Vasconcellos Carvalhaes de Oliveira, Maria Helena Araújo-Melo, Maria Inês Fernandes Pimentel, Ananda Dutra da Costa, Érica de Camargo Ferreira Vasconcellos, Marcelo Rosandiski Lyra, Ester Cleisla dos Anjos Soares, Lúcia Regina do Nascimento Brahim Paes, Mariza Mattos Salgueiro, Armando de Oliveira Schubach, and Cláudia Maria Valete
- Subjects
Medicine ,Science - Published
- 2024
41. Molecular hybridization as a powerful tool towards multitarget quinoidal systems: synthesis, trypanocidal and antitumor activities of naphthoquinone-based 5-iodo-1,4-disubstituted-, 1,4- and 1,5-disubstituted-1,2,3-triazoles
- Author
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Carlos A. de Simone, Maria Helena Araujo, Samara Ben B. B. Bahia, Cláudia Pessoa, Rubem F. S. Menna-Barreto, Bruno C. Cavalcanti, Wallace J. Reis, Solange L. de Castro, Eufrânio N. da Silva Júnior, Claudia C. Gatto, Francielly T. Souto, and Guilherme A. M. Jardim
- Subjects
Drug ,Chagas disease ,Stereochemistry ,media_common.quotation_subject ,Pharmaceutical Science ,Biology ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Peripheral blood mononuclear cell ,chemistry.chemical_compound ,Drug Discovery ,medicine ,Cytotoxic T cell ,IC50 ,media_common ,Pharmacology ,010405 organic chemistry ,Organic Chemistry ,medicine.disease ,Naphthoquinone ,0104 chemical sciences ,Molecular hybridization ,chemistry ,Benznidazole ,Molecular Medicine ,medicine.drug - Abstract
Quinonoid compounds based on 5-iodo-1,4-disubstituted-, 1,4- and 1,5-disubstituted-1,2,3-triazoles were synthesized using simple methodologies and evaluated against T. cruzi, the etiological agent of Chagas disease, and cancer cell lines PC3, HCT-116, HL-60, MDA-MB-435 and SF-295. The cytotoxic potential of the lapachones was also assayed against peripheral blood mononuclear cells (PBMC). Two compounds 6 and 12 were identified as potential hits against T. cruzi. β-Lapachone-based 1,5-disubstituted-1,2,3-triazole (12) displayed an IC50/24 h = 125.1 μM, similar to benznidazole, the standard drug. Compound 12 was also more active than the precursor β-lapachone against the cancer cell lines. These compounds acting as multitarget quinoidal systems could provide promising new leads for the development of trypanocidal and/or anticancer drugs.
- Published
- 2016
42. Positron annihilation studies in binary solid solutions and mechanical mixtures of lanthanide dipivaloylmethanate complexes
- Author
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Dario Windmöller, José C. Machado, F. Fulgêncio, F.C. Oliveira, Maria Helena Araujo, A. Marques-Netto, and W.F. Magalhães
- Subjects
Lanthanide ,Crystallography ,Quenching (fluorescence) ,Chemistry ,Intermolecular force ,Annihilation radiation ,General Physics and Astronomy ,Binary number ,Physical chemistry ,Physical and Theoretical Chemistry ,Doppler broadening ,Solid solution ,Positronium - Abstract
Measurements using positron annihilation lifetime (PALS) and Doppler broadening annihilation radiation lineshape (DBARLS) spectroscopies were performed in several lanthanide dipivaloylmethanate complexes, Ln(dpm) 3 where Ln = Sm 3+ , Gd 3+ , Tb 3+ , Ho 3+ , Er 3+ , Yb 3+ and dpm = 2,2,6,6-tetramethyl-3,5-pentanedionate, and also on their binary solid solutions and mechanical mixtures, biphasic systems, of the general formula Ln 1− x Eu x (dpm) 3 . Expressive positronium formation was observed in all Ln(dpm) 3 complexes, except in Eu(dpm) 3 complex. The results indicate formation of solid solutions in the Sm 3+ , Gd 3+ and Tb 3+ systems, where total inhibition of positronium formation was observed. A Stern–Volmer type equation, I 3 0 / I 3 = 1 + kx , was used to fit the data, enabling the calculation of the inhibition constants, k . A mechanical mixture behavior, with linear variation of I 3 between the I 3 values of the pure complexes, was observed in systems containing Ho 3+ , Er 3+ and Yb 3+ complexes, where no effective solid solution formation occurred due to differences between the crystalline structures of these complexes and Eu(dpm) 3 . No positronium quenching reactions were observed in the solid solutions. DBARLS results confirmed those of PALS, evidencing that the positron annihilation spectroscopies are useful techniques to characterize the formation of solid solutions. PALS measurements at 80 K were performed in the Sm 1− x Eu x (dpm) 3 and Gd 1− x Eu x (dpm) 3 solid solutions. The results indicate that, despite a contraction in the crystalline structures, the solid solution structure remains intact at low temperatures. The temperature dependence of the inhibition constant do not seem to be understood from the positronium formation spur model and might be related to intra and intermolecular energy and charge transfer processes in the solid solutions, which is currently being studied.
- Published
- 2015
43. Experimental and theoretical investigations of the [Ln(β-dik)(NO3)2(phen)2]⋅H2O luminescent complexes
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Israel F. Costa, Iran F. da Silva, Paulo R.S. Santos, Oscar L. Malta, Albano N. Carneiro Neto, Ercules E.S. Teotonio, Renata Diniz, Dariston K. S. Pereira, Maria Helena Araujo, Hermi F. Brito, Renaldo T. Moura, and Wagner M. Faustino
- Subjects
chemistry.chemical_classification ,Thermogravimetric analysis ,Quenching (fluorescence) ,Materials science ,Biophysics ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Biochemistry ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Coordination complex ,chemistry ,Elemental analysis ,Physical chemistry ,Experimental methods ,Fourier transform infrared spectroscopy ,0210 nano-technology ,Luminescence ,Monoclinic crystal system - Abstract
In this work, the coordination compounds presenting the formulas [Eu(acac)(NO3)2 (phen)2]⋅H2O (Eu1) and [Eu(bzac)(NO3)2(phen)2]⋅H2O (Eu2), acac: acetylacetonate, bzac: benzoylacetonate and, phen: 1,10-phenantroline, were successfully synthesized and some spectroscopic properties were investigated by theoretical and experimental methods. These compounds were characterized via elemental analysis, FTIR spectroscopy and thermogravimetric analysis (TGA). The X-ray diffraction data revealed that the compound Eu1 crystallizes in the monoclinic space group P2/n. Spectroscopic data showed that ligand-to-metal charge transfer states (LMCT) in the [Eu(β-dik)(NO3)2(phen)2]⋅H2O complexes (β-dik: acac or bzac) are redshift as compared with [Eu(β-dik)3(phen)] complexes. These data showed that LMCT states play the most important role on the luminescence quenching in the complexes Eu1 and Eu2, which only exhibit high luminescence intensities at low temperatures. Furthermore, the role of changes in the chemical environment on the intensity parameters Ωλ (λ = 2 and 4) have been investigated from the theoretical point of view for the complexes Eu1 to Eu2, and from these to tris β–dik complexes. Interestingly, the theoretical intensity parameters ratio Ω2/Ω4 calculated are in a good agreement with those experimental ones.
- Published
- 2020
44. A prática de exercícios físicos aeróbios na melhoria da saúde de mulheres na pós-menopausa
- Author
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João Ricardo Alves Fecury, Keulle Oliveira da Souza, Amanda Alves Fecury, Matheus Tavares Silva, Claudio Alberto Gellis de Mattos Dias, Iracely Rodrigues da Silva, Maria Helena Araujo, Carla Viana Dendasck, Jones Souza Moraes, Cícero Augusto Chaves Gomes, Euzébio de Oliveira, and Elisângela Cláudia de Medeiros Moreira
- Subjects
Gynecology ,lcsh:LC8-6691 ,medicine.medical_specialty ,030219 obstetrics & reproductive medicine ,lcsh:Special aspects of education ,business.industry ,Exercício físico ,030204 cardiovascular system & hematology ,lcsh:Social Sciences ,lcsh:H ,Sintomas incomodativos ,03 medical and health sciences ,0302 clinical medicine ,medicine ,General Earth and Planetary Sciences ,lcsh:Science (General) ,business ,Menopausa ,lcsh:Q1-390 ,General Environmental Science - Abstract
O presente artigo teve como objetivo avaliar os benefícios da prática do exercício físico sistematizado em mulheres que sofrem com os sintomas incomodativos da menopausa na cidade de Castanhal-PA, comparando dados de mulheres menopáusicas fisicamente ativas com de mulheres também menopáusicas, porém sedentárias, mediante aplicação do questionário da Escala de Avaliação da Menopausa (MRS - Menopause Rating Scale), do Índice de Massa Corpórea (IMC) e da Circunferência da Cintura (CC). O desenho deste estudo é descritivo e transversal, e avaliou 33 mulheres menopáusicas, sendo 17 fisicamente ativas e 16 sedentárias. O MRS avaliou as participantes em três domínios: sintomas somato-vegetativos, sintomas psicológicos e sintomas urogenitais. As fisicamente ativas apresentaram menor severidade em todos os domínios. De acordo com o IMC, observou-se que das sedentárias 38% estavam com obesidade grau I e 6% com obesidade grau II enquanto que apenas 6% das fisicamente ativas com obesidade grau I e nenhuma na condição de obesidade grau II. Em relação a CC, de todas as participantes da pesquisa 29% das fisicamente ativas apresentaram sem risco, por outro lado somente 6% das sedentárias se mostraram sem risco para doenças associadas à obesidade. No presente estudo o exercício físico aeróbio regular de intensidade controlada influenciaram positivamente a qualidade de vida e a intensidade da sintomatologia climatérica.
- Published
- 2020
45. Participação do gênero feminino em Cursos Técnicos da Rede Federal no Brasil e no Amapá (2018)
- Author
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Keulle Oliveira da Souza, Carla Viana Dendasck, Jucimeire Rocha Macêdo, Maria Helena Araujo, Amanda Alves Fecury, Euzébio de Oliveira, Jamilli Santos Martins Pereira, Nadabe de Jesus da Silva Cordeiro, Claudio Alberto Gellis de Mattos Dias, Jones Souza Moraes, and Elisângela Cláudia de Medeiros Moreira
- Subjects
Gender equity ,Geography ,Inequality ,Work (electrical) ,Vocational education ,media_common.quotation_subject ,Significant difference ,General Earth and Planetary Sciences ,National level ,Socioeconomics ,General Environmental Science ,media_common - Abstract
O objetivo deste trabalho foi analisar a participação do gênero feminino em cursos técnicos da Rede Federal no Brasil e no Amapá em 2018, por faixa etária. A abordagem deste estudo é de natureza quanti-qualitativa. Os dados coletados foram oriundos do banco de dados Plataforma Nilo Peçanha. Os resultados mostraram que tanto no Brasil quanto no Estado do Amapá houve um predomínio de mulheres matriculadas nos institutos de ensino, no ano de 2018. A nível nacional, os dados mostraram que mulheres com menos de 20 anos são maioria nos Institutos Federais de ensino, enquanto que no Estado do Amapá verificou-se o inverso. Nacionalmente, na faixa etária de 20 a 34 os matriculados se igualam. No Amapá, na faixa etária de 20 a 34 anos há um leve predomínio das mulheres. Os dados mostram ainda que há uma diferença (queda) significativa na porcentagem de mulheres com 50 anos ou mais no ensino técnico. Embora se observe um avanço, ainda existe muita desigualdade entre homens e mulheres e um longo caminho para alcançar a equidade entre os gêneros.
- Published
- 2020
46. Características físico-químicas, cozimento e textura de arroz polido e integral de diferentes variedades comercializadas no Brasil
- Author
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Géssica Regiane Silva, Eleonice Moreira Santos, Tatiana Aparecida Ribeiro dos Santos Benfica, Amanda Souza da Silva, Felipe Machado Trombete, Kerolaine Lijanda Anselmo, Maria Helena Araujo, Clara Mariana Gonçalves Lima, and Washington Azevedo da Silva
- Subjects
Zizania aquática ,Black rice ,Whole grain ,Oryza sativa ,Wild rice ,Health benefits ,Texture (geology) ,Grãos de cereais ,Grão integral ,lcsh:Social Sciences ,Protein content ,wild rice ,Food science ,lcsh:Science (General) ,Water content ,General Environmental Science ,Mathematics ,lcsh:LC8-6691 ,lcsh:Special aspects of education ,zizania aquatic ,arroz silvestre ,technology, industry, and agriculture ,Red rice ,cereal grains, whole grain ,food and beverages ,Arroz selvagem ,Zizania aquatic ,granos integrales ,lcsh:H ,oryza sativa ,Cereal grains ,Zizania aquatica ,granos de cereales ,White rice ,General Earth and Planetary Sciences ,Brown rice ,lcsh:Q1-390 - Abstract
The diversity of whole rice grains with black and red pericarp has been valued in Brazil due to its different characteristics of color, texture, and also due to the association with health benefits. This work aimed to evaluate the physicochemical, cooking, and textural characteristics of different samples of polished and whole rice grains from different varieties marketed in Brazil. A total of 28 samples were collected and divided into 6 groups: polished white rice, white polished parboiled rice, whole white rice, whole red rice, whole black rice, and whole wild rice. Moisture content, crude protein, ash, mineral content, hardness, and adhesiveness were analyzed. The cooking quality was evaluated through the determination of cooking time, swelling ratio, and volume expansion ratio. A strong correlation between the protein content and the hardness value of cooked grains was observed. The polished samples showed the lowest ash and mineral values and the shortest cooking time. A strong correlation was also observed for the volume expansion ratio and hardness of cooked samples. The data obtained contribute to a better understanding of the quality of the rice marketed in Brazil and demonstrate a large variation among samples in terms of physicochemical, cooking, and texture properties. La diversidad del arroz integral con pericarpio negro y rojo se ha valorado en Brasil debido a las diferentes características de color, textura y también por la asociación con los beneficios para la salud. El objetivo de este trabajo fue evaluar las características físico-químicas, de cocción y de textura de muestras de arroz pulido y integral de diferentes variedades vendidas en Brasil. Se realizó un muestreo exploratorio y aleatorizado, con el objetivo de adquirir el mayor número de marcas. Se recolectaron 28 muestras y se dividieron en 6 grupos: arroz blanco pulido, arroz blanco precocido, arroz integral blanco, arroz integral rojo, arroz integral negro y arroz integral silvestre. Se analizaron los contenidos de humedad, proteínas, cenizas, minerales, dureza y adhesividad. La calidad de cocción se evaluó determinando el tiempo de cocción, el índice de absorción de agua y el índice de expansión. Se observó una fuerte correlación entre el contenido de proteína y el valor de dureza de los granos cocidos. Las muestras de arroz pulido mostraron los valores más bajos de cenizas y minerales y el tiempo de cocción más corto. Se observó una fuerte correlación entre el índice de expansión y el valor de dureza de las muestras cocidas. Los resultados obtenidos contribuyen a una mejor comprensión de la calidad del arroz vendido en Brasil y demuestran una gran variación entre las muestras en términos de propiedades físico-químicas, cocción y textura. As diversidades de arroz integral de pericarpo preto e vermelho têm sido valorizadas no Brasil devido às diferentes características de cor, textura e também pela associação com benefícios à saúde. Esse trabalho teve como objetivo avaliar as características físico-químicas, de cozimento e textura de amostras de arroz polido e integral de diferentes variedades comercializadas no Brasil. Foi realizada uma amostragem exploratória e aleatorizada, objetivando adquirir o maior número de marcas, sendo coletadas 28 amostras e divididas em 6 grupos: arroz branco polido, arroz branco parboilizado polido, arroz branco integral, arroz vermelho integral, arroz preto integral e arroz selvagem integral. Foram analisados os teores de umidade, proteína, cinzas, minerais, dureza e adesividade. A qualidade de cozimento foi avaliada através da determinação do tempo de cozimento, índice de absorção de água e índice de expansão. Foi observada uma forte correlação entre o teor de proteína e o valor de dureza dos grãos cozidos. As amostras de arroz polido apresentaram os menores valores de cinzas e minerais e menor tempo de cozimento. Foi observada uma forte correlação entre o índice de expansão e o valor de dureza das amostras cozidas. Os resultados obtidos contribuem para uma melhor compreensão da qualidade do arroz comercializado no Brasil e demonstram uma grande variação entre as amostras em termos de propriedades físico-químicas, cozimento e textura.
- Published
- 2020
47. Study of the interactions of the hazardous amoxicillin antibiotic inside the MCM-41/CTA hydrophobic cavities
- Author
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W.F. Magalhães, Fernando Fulgêncio Henriques, Tatiana A. Ribeiro-Santos, Ana Paula C. Teixeira, Mateus Carvalho Monteiro de Castro, Maria Helena Araujo, Rochel M. Lago, Luisa E. Milagre, and Dario Windmöller
- Subjects
Chemistry ,Diffusion ,Composite number ,Sorption ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Positron annihilation spectroscopy ,Colloid and Surface Chemistry ,Adsorption ,MCM-41 ,Chemical engineering ,medicine ,Molecule ,0210 nano-technology ,Activated carbon ,medicine.drug - Abstract
In this work, it was studied the interaction of the hazardous antibiotic amoxicillin (AMX) molecules inside the mesocavities of a composite MCM-41/cetyltrimethylammonium (MCTA). MCTA with low surface area (5 m2 g−1) showed high sorption efficiency of AMX (55 mgAMX g−1) comparable with high surface area activated carbon (980 m2 g−1). Positron annihilation spectroscopy and isosteric heats suggested that the AMX molecules are not adsorbed by a classical surface process but are attracted and trapped by the CTA C18 hydrophobic chains inside the MCM-41 mesocavities. Preliminary kinetic data suggests that the AMX sorption process takes place in three stages, the external adsorption, interaction with the CTA molecules and diffusion inside the mesocavities.
- Published
- 2019
48. Iron Oxide Nanoparticles Supported on Mesoporous MCM-41 for Efficient Adsorption of Hazardous β-Lactamic Antibiotics
- Author
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Adriana Barbosa Salviano, José D. Ardisson, Rochel Montero Lago, Maria Helena Araujo, Mariana Rocha Dutra Santos, and Laura Maia De Araújo
- Subjects
Environmental Engineering ,Chemistry ,Ecological Modeling ,02 engineering and technology ,010501 environmental sciences ,Hematite ,021001 nanoscience & nanotechnology ,01 natural sciences ,Pollution ,Decomposition ,chemistry.chemical_compound ,Adsorption ,MCM-41 ,visual_art ,Mössbauer spectroscopy ,visual_art.visual_art_medium ,Environmental Chemistry ,Crystallite ,0210 nano-technology ,Mesoporous material ,Iron oxide nanoparticles ,0105 earth and related environmental sciences ,Water Science and Technology ,Nuclear chemistry - Abstract
In this work, the effect of crystallite size, defects, and surface area of iron oxyhydroxide particles supported on mesoporous MCM-41 on the adsorption of hazardous β-lactamic antibiotics was investigated. Different adsorbents were prepared by impregnation of 5, 10, 20, and 50 wt% of Fe followed by treatment at 150–400 °C. Mossbauer, XRD, BET, TG, FTIR, and Raman analyses suggested that treatment at 150 °C produced a mixture of α-Fe2O3, FeOOH, and highly dispersed Fe3+ species. At higher temperatures, different phases were gradually converted to hematite with crystallite sizes varying from 1 to 5 nm. Both, Fe content and temperature, strongly affected the amoxicillin, cephalexin, and ceftriaxone adsorption at pH 5, 7, and 9, with the best results obtained for the sample 20Fe150 (20% Fe treated at 150 °C), ca. 25 mgAMX g−1 which decreased to 17, 6, and 4 mgAMX g−1 (AMX = amoxicillin) upon treatment at higher temperatures. These results combined with competitive adsorption using AMX/phosphate and H2O2 decomposition experiments suggested that the antibiotic molecules are likely adsorbing by complexation on Fe3+ surface species of poorly crystallized small particles of Fe oxyhydroxide phases. It was observed that below a critical crystallite size of 3 nm, the AMX adsorption was very sensitive and strongly increased.
- Published
- 2018
49. Ruthenium Complexes as Antifungal Agents
- Author
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Maria Aparecida de Resende Stoianoff, Claudio Luis Donnici, and Maria Helena Araujo
- Subjects
Antifungal ,chemistry ,medicine.drug_class ,medicine ,chemistry.chemical_element ,Combinatorial chemistry ,Ruthenium - Published
- 2017
50. Surface modified Fe/silica floating magnetic materials for efficient oil removal
- Author
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Rochel Montero Lago, Bárbara Carolina Lourenço Papa Martins, Maria Helena Araujo, and Lílian Amaral Carvalho
- Subjects
Materials science ,General Chemical Engineering ,Octadecyltrimethoxysilane ,Iron oxide ,Nanoparticle ,02 engineering and technology ,Thermal treatment ,010402 general chemistry ,01 natural sciences ,Inorganic Chemistry ,Contact angle ,chemistry.chemical_compound ,Organic chemistry ,Waste Management and Disposal ,Renewable Energy, Sustainability and the Environment ,Organic Chemistry ,Xylene ,021001 nanoscience & nanotechnology ,Pollution ,0104 chemical sciences ,Hydrophobe ,Fuel Technology ,Chemical engineering ,chemistry ,Hydroxide ,0210 nano-technology ,Biotechnology - Abstract
BACKGROUND Remediation of oil spillage accidents requires efficient and low cost floating absorbents to remove small amounts of contaminant oil. In this work, a highly hydrophobic floating magnetic macroporous structure based on silica encapsulated Fe nanoparticles was prepared and used for oil absorption from water. RESULTS The magnetic macroporous materials were prepared by silica encapsulation of iron oxide/hydroxide nanoparticles followed by a thermal treatment with H2. Mossbauer, XRD, SEM/TEM, CHN, IR, TG/DTA and contact angle analyses showed that the Fe oxides nanoparticles are reduced by H2 to form Feo cores protected by silica which sinters to form a macroporous network. The surface reaction with octadecyltrimethoxysilane (Si(CH3O)3C18H37) was used to produce highly hydrophobic materials. CONCLUSIONS The materials obtained showed very high oil absorption capacities for different model contaminants, i.e. petroleum, soy bean oil, diesel, gasoline and xylene removal. The results are discussed in terms of a macroporous structure with strong capillarity combined with a very hydrophobic surface. © 2015 Society of Chemical Industry
- Published
- 2015
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