Repositório Institucional - Unifesp :: Navegando por Palavras-chave "Raman spectroscopy"

Navegando por Palavras-chave "Raman spectroscopy"

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A comparative study of epoxy and polyurethane based coatings containing polyaniline-DBSA pigments for corrosion protection on mild steel
(Elsevier B.V., 2013-05-01) Diniz, F. B.; De Andrade, G. F.; Martins, C. R. [UNIFESP]; De Azevedo, W. M.; Universidade Federal de Pernambuco (UFPE); Universidade Federal de São Paulo (UNIFESP)
Organic coatings based on epoxy and polyurethane matrices containing polyaniline doped with dodecyl benzene sulfonic acid (Pani-DBSA) were prepared and applied over steel plates (SAE 1020). the plates were submitted to salt spray chamber for up to 30 days in order to evaluate the corrosion protection of these coatings. the properties of the coated plates were analyzed as a function of time by electrochemical impedance spectroscopy, open circuit potential, optical microscopy, and Raman spectroscopy. in general, results indicate a decrease in the electrical resistance, increase in capacitance and decrease in open circuit potential. Epoxy based coatings have improved performance when Pani-DBSA is used as pigment, whereas for the polyurethane coatings, Pani-DBSA seems to play an adverse effect. Raman spectroscopy indicates a possible chlorination of the epoxy matrix after 30 days exposure to salt spray chamber. (C) 2013 Elsevier B.V. All rights reserved.
Acesso aberto (Open Access)
Espectroscopia Raman e UV-Vis de amostras de cianita natural
(Universidade Federal de São Paulo, 2023-12-15) Teixeira, Francielle Gonçalves [UNIFESP]; Kunzel, Roseli [UNIFESP]; http://lattes.cnpq.br/6662626014913141; http://lattes.cnpq.br/2462941790242730
A caracterização de minerais naturais tem motivado diversas publicações e tem mobilizado pesquisadores de diferentes áreas e é responsável por avanços científicos e tecnológicos. Este trabalho teve como propósito estudar as propriedades ópticas e vibracionais de amostras de cianita natural azul e verde obtidas comercialmente e provenientes de Minas Gerais. As amostras em bruto foram pulverizadas e posteriormente analisadas por meio dos espectros de absorção óptica (UV-Vis), espectroscopia Raman e Fluorescência Raios X (FRX). Os dados de fluorescência de raios X evidenciaram a presença dos principais componentes presentes nas amostras de cianita que se devem ao Silício, Alumínio (Al), Ferro (Fe) e Titânio (Ti). As amostras de cianita verde também mostraram picos de raios X característicos do Cromo (Cr) e Cálcio (Ca), enquanto nas amostras de cianita azul foi possível observar a presença de Vanádio (V) e Níquel (Ni). Os dados de FRX também evidenciam uma maior concentração de Ferro nas amostras de cianita verde em comparação a amostra de cianita azul. Na espectroscopia Raman foi possível observar bandas de vibração características do grupo (SiO₄)-4 e ligações Al-O, observado nos compostos Al₂SiO₅. Os espectros obtidos para a cianita azul e verde obtidos neste trabalho são similares, mostrando apenas pequenas diferenças nas intensidades de algumas bandas. O espectro Raman para a cianita azul foi comparado a um espectro característico para esse mineral disponível na página do projeto RRUFF para minerais e mostraram boa concordância, indicando que as amostras estudadas neste trabalho correspondem a cianita. A espectroscopia UV-VIS forneceu informações sobre as bandas de absorção na cianita azul e verde e os fenômenos responsáveis pela coloração. Esse estudo também proporcionou compreender e a ver a Física Moderna através da Física Experimental.
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Improvement of carbon dioxide absorption by mixing poly(ethylene glycol) dimethyl ether with ammonium-based ionic liquids
(Elsevier Science Bv, 2018) Lepre, L. F.; Pison, L.; Siqueira, L. J. A. [UNIFESP]; Ando, R. A.; Gomes, M. F. Costa
Mixtures of the ionic liquid butyltrimethylammonium bis(trifluoromethylsulfonyl)imide, [N-4111][NTf2] with poly(ethylene oxide) polymers, PEO, of different molecular weights were investigated for CO2 capture. The liquid mixtures are close to ideal in terms of their volumetric properties but their enthalpies of mixing are negative, decreasing when the size of the polymer chain increases and being close to those observed for associative compounds mixed with ionic liquids (Delta H-mix = -7 kJ mol(-1) for [N-4111][NTf2] + PEO1000 at 318 K). The favorable interactions between the polymer and the ionic liquid could be related to the dynamic properties of the mixtures, especially for mixtures of polymers of longer chain sizes which have a higher viscosity than that of the pure mixture components. Raman spectroscopy confirmed an association between the cation of the ionic liquid and the polymers that probably surround the cation and thus contribute to slow the dynamics of the mixtures. The increase of the carbon dioxide absorption with the increase of the polymer mole fraction composition in the liquid mixture is explained by the more favorable interactions between the gas and the polymer as evidenced by the analysis of the thermodynamic properties of solvation. (C) 2017 Elsevier B.V. All rights reserved.
Somente Metadadados
In vivo confocal Raman spectroscopy for intrinsic aging and photoaging assessment
(Elsevier Ireland Ltd, 2017) Nasser Caetano, Livia de Vasconcelos [UNIFESP]; Mendes, Thiago de Oliveira; Bagatin, Edileia [UNIFESP]; Miot, Helio Amante; Marques Soares, Juliana Laudiceia [UNIFESP]; Enokihara, Milvia Maria Simoes e Silva [UNIFESP]; Martin, Airton Abrahao
Background: In vivo confocal Raman spectroscopy is a non-invasive method to assess either the epidermis or the dermis composition. Few studies have focused on dermis collagen alterations through intrinsic aging and photoaging. Objective: This study evaluated the in vivo Raman spectra from the dermis of a photoexposed site versus a non-photoexposed region in different age groups, and evaluated the correlation between peak intensities and age, photoaging score and the amount of collagen assessed with histology and high frequency ultrasound (HFUS). Methods: Fifteen volunteers aged 28-82 years were divided into three groups according to forearm photoaging degree. In vivo Raman spectra from the dermis were collected on the dorsal forearm (chronically photoexposed skin) and on the proximal medial arm (non-photoexposed skin). Crosssectional images of the skin were obtained using a 20 MHz ultrasound unit exactly on the same sites, which were further submitted to punch biopsies for histologic study (collagen I immunohistochemistry, picrosirius red staining and Verhoeff). Principal Component Analysis (PCA) and Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA) were taken in the spectral region of 796 cm(-1) -996 cm(-1) to determine its potential to discriminate between different groups. The Spearman rank correlation coefficient of individual peak intensities and ratios with age, clinical score and the amount of collagen assessed by ultrasound and histology were calculated. Results: PCA of pairs of groups and OPLS-DA could discriminate the intrinsically from the photoaged skin and the young group from the elderly one, with important contribution of the 938 cm(-1) and 855 cm(-1) peaks intensities. The intensity of the peaks in 855 cm(-1) and/or 938 cm(-1) presented moderate correlation with age (rho = 0.579, p = 0.049) and moderate to high inverse correlation with HFUS echogenicity (rho = -0.710, p = 0.010) and collagen I immunohistochemistry (rho = -0.833, p = 0.005) in the non-photoexposed region. The I-1275/I-1450 intensities ratio presented moderate to high correlation coefficients with age (rho = -0.730, p = 0.007), photoaging score (rho = -0.594, p = 0.042), HFUS echogenicity (rho = 0.760, p < 0.001) and histology (collagen I immunohistochemistry (rho = 0.643, p = 0.024), picrosirius (rho = 0.773, p = 0.005) and Verhoeff (rho = -0.727, p = 0.011)) in the photoexposed site. Conclusion: The wavenumber region between 798 and 994 cm(-1) is useful for the analysis of dermal collagen alterations through the intrinsic aging process, while photoaging is better assessed by the I-1275/I-1450 intensities ratio. This is the first skin aging study to show a correlation between Raman peaks and the amount of collagen assessed by HFUS- and histology. (C) 2017 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.
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Intralamellar structural modifications related to the proton exchanging in K4Nb6O17 layered phase
(Elsevier B.V., 2010-04-01) Bizeto, M. A. [UNIFESP]; Leroux, F.; Shiguihara, A. L.; Temperini, M. L. A.; Sala, O.; Constantino, V. R. L.; Univ Clermont Ferrand; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP)
Basic structural aspects about the layered hexaniobate of K4Nb6O17 composition and its proton-exchanged form were investigated mainly by spectroscopic techniques. Raman spectra of hydrous K4Nb6O17 and H2K2Nb6O17 center dot H2O show significant modifications in the 950-800 cm(-1) region (Nb-O stretching mode of highly distorted NbO6 octahedra). the band at 900 cm(-1) shifts to 940 cm(-1) after the replacement of K+ ion by proton. Raman spectra of the original materials and the related deuterated samples are similar suggesting that no isotopic effect occurs. Major modifications were observed when H2K2Nb6O17 was dehydrated: the relative intensity of the band at 940 cm(-1) decreases and new bands seems to be present at about 860-890 cm(-1). the H+ ions should be shielded by the hydration sphere what preclude the interaction with the layers. Removing the water molecules, H+ ions can establish a strong interaction with oxygen atoms, decreasing the bond order of Nb-O linkage. X-ray absorption near edge structure studies performed at Nb K-edge indicate that the niobium coordination number and oxidation state remain identical after the replacement of potassium by proton. From the refinement of the fine structure, it appears that the Nb-Nb coordination shell is divided into two main contributions of about 0.33 and 0.39 nm, and interestingly the population, i.e., the number of backscattering atoms is inversed between the two hexaniobate materials. 2009 Elsevier B.V. All rights reserved.
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Morphological and chemical changes in dentin after using endodontic agents: Fourier transform Raman spectroscopy, energy-dispersive x-ray fluorescence spectrometry, and scanning electron microscopy study
(Spie-soc Photo-optical Instrumentation Engineers, 2012-07-01) Pascon, Fernanda Miori; Kantovitz, Kamila Rosamilia; Silva Soares, Luis Eduardo; Santo, Ana Maria do Espírito [UNIFESP]; Martin, Airton Abrahao; Puppin-Rontani, Regina Maria; Universidade Estadual de Campinas (UNICAMP); NIAMSD; Vale Paraiba Univ UNIVAP; Universidade Federal de São Paulo (UNIFESP)
We examine the morphological and chemical changes in the pulp chamber dentin after using endodontic agents by scanning electron microscopy (SEM), Fourier transform Raman spectroscopy (FT-Raman), and micro energy-dispersive x-ray fluorescence spectrometry (mu EDXRF). Thirty teeth were sectioned exposing the pulp chamber and divided by six groups (n = 5): NT-no treatment; CHX-2% chlorhexidine; CHXE-2% chlorhexidine + 17% EDTA; E-17% EDTA; SH5-5.25% NaOCl; SH5E-5.25% NaOCl + 17% EDTA. the inorganic and organic content was analyzed by FT-Raman. mu EDXRF examined calcium (Ca) and phosphorus (P) content as well as Ca/P ratio. Impressions of specimens were evaluated by SEM. Data were submitted to Kruskal-Wallis and Dunn tests (p < 0.05). Differences were observed among groups for the 960 cm(-1) peak. Ca and P content differences were significant (SH5 > NT = SH5E > CHX > E > CHXE). CHXE and E presented the highest Ca/P ratio values compared to the other groups (p < 0.05). the SEM images in the EDTA-treated groups had the highest number of open tubules. Erosion in the tubules was observed in CHX and SH5E groups. Endodontic agents change the inorganic and organic content of pulp chamber dentin. NaOCl used alone, or in association with EDTA, was the most effective agent considering chemical and morphological approaches. (C) 2012 Society of Photo-Optical Instrumentation Engineers (SPIE). IDOL 10.1117/1.JBO.17.7.075008
Embargo
Nanocompósitos de polímero conjugado dopados com nanopartículas plasmônicas de prata e sua aplicação como sensor na detecção de pesticidas
(Universidade Federal de São Paulo, 2024-12-19) Rodrigues, Rebeca da Rocha [UNIFESP]; Péres, Laura Oliveira [UNIFESP]; Pellosi, Diogo Silva [UNIFESP]; http://lattes.cnpq.br/4319283598735971; http://lattes.cnpq.br/7511492642565571; http://lattes.cnpq.br/9618062467548002
Este trabalho investigou filmes nanoestruturados de compósitos do copolímero conjugado poli(9,9-dioctilfluoreno-co-3,4-etilenodioxitiofeno) (PDOF-co-PEDOT) e nanopartículas de prata (AgNP), como substratos para a técnica de Espalhamento Raman Intensificado por Superfície (efeito SERS), visando detectar o pesticida clorpirifós, encontrado em concentrações inadequadas na água de consumo no Brasil. O copolímero foi sintetizado via rota de Suzuki e as AgNP, esféricas e triangulares, foram obtidas via redução do sal de prata (nitrato de prata). O material compósito contendo o nanopolímero (NCP) ou PDOF-co-PEDOT e AgNP apresentou alterações ópticas associadas à interação copolímero-AgNP, como deslocamento dos máximos de absorção e emissão para maiores comprimentos de onda devido a formação de agregados poliméricos e excímeros. Posteriormente, filmes foram preparados pelas técnicas de Spin Coating, Drop Casting e Langmuir-Blodgett. Imagens de TEM e AFM confirmaram a estruturação das dispersões e transferência bem-sucedida para substratos sólidos, embora a homogeneidade dependesse da geometria das AgNP e método de deposição. Filmes com AgNP esféricas produziram sinais SERS mais intensos devido à geração uniforme de hot spots, enquanto desafios na reprodutibilidade foram atribuídos à dificuldade de distribuição homogênea das AgNP nos filmes. A presença de PDOF-co-PEDOT ampliou o efeito SERS ao facilitar a transferência de carga entre as AgNP e o pesticida, demonstrando limites de detecção promissores de 0,0015 g L-1 e 0,0014 g L-1 (filme PDOF-co-PEDOT/AgNP e NCP/AgNP, respectivamente), porém ainda superiores ao permitido para água potável (30 g L-1). Os resultados destacam o potencial dos substratos híbridos SERS para aplicações futuras, com oportunidades de otimização para maior sensibilidade e reprodutibilidade.
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Probing the local environment of hybrid materials designed from ionic liquids and synthetic clay by Raman spectroscopy
(Elsevier B.V., 2014-03-25) Siqueira, Leonardo J. A. [UNIFESP]; Constantino, Vera R. L.; Camilo, Fernanda F. [UNIFESP]; Torresi, Roberto M.; Temperini, Marcia L. A.; Ribeiro, Mauro C. C.; Izumi, Celly M. S.; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP)
Hybrid organic-inorganic material containing Laponite clay and ionic liquids forming cations have been prepared and characterized by FT-Raman spectroscopy, X-ray diffraction, and thermal analysis. the effect of varying the length of the alkyl side chain and conformations of cations has been investigated by using different ionic liquids based on piperidinium and imidazolium cations. the structure of the N,N-butyl-methyl-piperidinium cation and the assignment of its vibrational spectrum have been further elucidated by quantum chemistry calculations. the X-ray data indicate that the organic cations are intercalated parallel to the layers of the clay. Comparison of Raman spectra of pure ionic liquids with different anions and the resulting solid hybrid materials in which the organic cations have been intercalated into the clay characterizes the local environment experienced by the cations in the hybrid materials. the Raman spectra of hybrid materials suggest that the local environment of all confined cations, in spite of this diversity in properties, resembles the liquid state of ionic liquids with a relatively disordered structure. (C) 2013 Elsevier B.V. All rights reserved.
Acesso aberto (Open Access)
Production and Characterization of Activated Carbon Fiber from Textile PAN Fiber
(Inst Aeronautica & Espaco-Iae, 2017) do Amaral Junior, Miguel Angelo; Matsushima, Jorge Tadao; Rezende, Mirabel Cerqueira [UNIFESP]; Goncalves, Emerson Sarmento; Marcuzzo, Jossano Saldanha; Baldan, Mauricio Ribeiro
This paper presents the preparation and characterization of carbon fiber felt and activated carbon fiber felt from textile polyacrylonitrile fiber. Carbon fibers are usually related to aircraft manufacturing or high mechanical purposes. Activated carbon fibers are known as excellent adsorbent materials. Despite all advantages, carbon fiber and activated carbon fiber are expensive materials because of their raw material cost. On the other hand, in this study, carbon fiber felt and activated carbon fiber felt were produced from textile polyacrylonitrile fiber, which is cheaper than their precursor, polyacrylonitrile fiber, and can be converted into carbon fiber felt and activated material with high micropore content and surface area. This research describes the transformation of textile polyacrylonitrile fiber in its oxidized form. After that, the oxidized material was transformed in felt and, in the sequence, converted into carbon fiber felt and activated carbon felt. The carbon fiber felt and activated carbon fiber felt were characterized by X-ray photoelectron spectroscopy, Raman spectroscopy and scanning electron microscope. N-2 isotherms were performed to qualify the material obtained for further electrochemical applications. The main result was the conversion dynamics of textile polyacrilonitrile fiber into carbon fiber in felt form and activated carbon fiber in felt with high surface area and high micropores content.
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Raman spectra of polymer electrolytes based on poly(ethylene glycol) dimethyl ether, lithium perchlorate, and the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate
(Elsevier B.V., 2010-11-18) Costa, Luciano T.; Siqueira, Leonardo J. A. [UNIFESP]; Nicolau, Bruno G.; Ribeiro, Mauro C. C.; Universidade de São Paulo (USP); Univ Fed Alfenas; Universidade Federal de São Paulo (UNIFESP)
Raman spectra of polymer electrolytes based on poly(ethylene glycol) dimethyl ether (PEGdME) with LiClO(4), PEGdME/LiClO(4), and the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate, PEGdME/[bmim]PF(6), are compared. Raman spectroscopy suggests stronger interactions in PEGdME/LiClO(4) than PEGdmE/[bmim]PF(6), thus corroborating previous results obtained by molecular dynamics simulations. Quantum Chemistry methods have been used to calculate vibrational frequencies and the equilibrium structure of segments of the polymer chain around the cation. A consistent picture has been obtained from Raman spectroscopy, density functional theory (DFT) calculations, and molecular dynamics simulations for these polymer electrolytes. (C) 2010 Elsevier B.V. All rights reserved.
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Raman spectroscopy for differential diagnosis of endophthalmitis and uveitis in rabbit iris in vitro
(Elsevier B.V., 2010-09-01) Rossi, Eglas Emanuel; Silveira, Landulfo; Barbosa Pinheiro, Antonio Luiz; Zamuner, Stella Regina; Aimbire, Flavio; Maia, Mauricio [UNIFESP]; Tavares Pacheco, Marcos Tadeu; Univ Comunitaria Reg Chapeco UNOCHAPECO; Univ Camilo Castelo Branco UNICASTELO; Universidade Federal da Bahia (UFBA); Nove Julho Univ UNINOVE; Universidade Federal de São Paulo (UNIFESP)
We developed a diagnostic tool to differentiate between endophthalmitis and uveitis using Raman spectroscopy. Twenty-two New Zealand rabbits with endophthalmitis induced by Staphylococcus aureus (10 animals), noninfectious uveitis induced by lipopolysaccharide from Escherichia colt (10 animals) and controls (two animals) were analyzed. Twenty-four hours after the eyes were inoculated, iris tissue was dissected and subjected to dispersive Raman spectroscopy using an excitation source at 830 nm and a spectrograph/CCD camera to detect a Raman signal with an integration time of 50 s. With the collected spectra of endophthalmitis and uveitis, we developed a routine to classify spectra in each specimen using principal components analysis, using a leave-one-out cross-validation procedure. the mean Raman spectra of tissues with uveitis and endophthalmitis showed several bands in the region of 800-1800 cm(-1), which have been attributed to nucleic acids, amino acids, proteins, and lipids. the bands at 1004, 1339, and 1555 cm(-1) differed significantly (t-test. p < 0.05) between diseases. the principal components PC3 and PC4 differed significantly (ANOVA, p < 0.05) for the two tissue types, indicating that these PCs can be used to discriminate between the two diseases using Mahalanobis distance as a discriminator. This technique is useful for differentiating the spectral bands of uveitis and endophthalmitis, and the diagnostic model showed sensitivity of 89%, specificity of 100%, and accuracy of 92% using the leave-one-out cross-validation procedure. These results may be clinically relevant for differentiating endophthalmitis from uveitis, and this approach may become a noninvasive method to optimize the diagnosis of inflammatory and infectious vitreoretinal diseases. (C) 2010 Elsevier B.V. All rights reserved.
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Raman studies of nanocomposites catalysts: temperature and pressure effects of CeAl, CeMn and NiAl oxides
(Pergamon-Elsevier Science Ltd, 2018) Silva, Antonio N. da; Neto, Antonio B. S.; Oliveira, Alcemira C.; Junior, Manoel C.; Junior, Jose A. L.; Freire, Paulo T. C.; Filho, Josue M.; Oliveira, Alcineia C.; Lang, Rossano [UNIFESP]
High temperature and pressure effects on the physicochemical properties of binary oxides catalysts were investigated. The nanocomposites catalysts comprising of CeAI, CeMn and NiAl were characterized through various physicochemical techniques. A study of the temperature and pressure induced phenomena monitored by Raman spectroscopy was proposed and discussed. Spectral modifications of the Raman modes belonging to the CeMn suggest structural changes in the solid due to the MnO2 phase oxidation with increasing temperature. The thermal expansion and lattice anharmonicity effects were observed on CeMn due to lack of stability of the lattice vacancies. The CeAI and NiAl composites presented crystallographic stability at low temperatures however, undertake a phase transformation of NiO/Al2O3 into NiAl2O4, mostly without any deformation in its structure with increasing the temperature. It was also inferred that the binary oxides are more stables in comparison with monoxides. Detailed pressure-dependent Raman measurements of the T-2g phonon mode of CeMn and NiAl revealed that the pressure contributes to modify bonds length and reduces the particles sizes of the solids. On the contrary, high pressure on CeAI sample improved the stability with addition of Al2O3 in the CeO2 lattice. The results then suggest a good stability of CeAl and NiAl composite catalysts at high pressure and low temperature and show how to prospect of tuning the catalysis for surface reactions entirely through in situ spectroscopic investigations means. (C) 2018 Elsevier B.V. All rights reserved.
Acesso aberto (Open Access)
Safflower oil: an integrated assessment of phytochemistry, antiulcerogenic activity, and rodent and environmental toxicity
(Sociedade Brasileira de Farmacognosia, 2014-10-01) Toma, Walber; Guimarães, Luciana Lopes; Brito, Alba Regina Monteiro Souza; Santos, Aldo Ramos; Cortez, Fernando Sanzi; Pusceddu, Fabio Hermes; Cesar, Augusto [UNIFESP]; Silveira Junior, Landulfo; Pacheco, Marcos Tadeu Tavares; Pereira, Camilo Dias Seabra [UNIFESP]; Universidade Santa Cecília Programa de Pós-graduação em Sustentabilidade de Ecossistemas Costeiros e Marinhos Laboratório de Pesquisa em Produtos Naturais; Universidade Estadual de Campinas (UNICAMP); Universidade Santa Cecília Laboratório de Ecotoxicologia; Universidade Federal de São Paulo (UNIFESP); Universidade Camilo Castelo Branco Instituto de Engenharia Biomédica
Gastric ulcers are a significant medical problem and the development of complications lead to significant mortality rates worldwide. In Brazil, Carthamus tinctorius L., Asteraceae, seeds essential oil, the safflower oil, is currently used as a thermogenic compound and as treatment for problems related to the cardiovascular system. In this study, by Raman spectroscopy, it was shown that oleic and linoleic acids are the compounds present in higher concentrations in the safflower oil. We demonstrated that safflower oil (750 mg/kg, p.o.) decrease the ulcerogenic lesions in mice after the administration of hydrochloric acid-ethanol. The gastric ulcers induced by non-steroidal anti-inflammatory drug (NSAID) in mice treated with cholinomimetics were treated with four different doses of safflower oil, of which, the dose of 187.5 mg/kg (p.o.) showed significant antiulcerogenic properties (**p < 0.01). Moreover, the safflower oil at doses of 187.5 mg/kg (i.d.) increased the pH levels, gastric volume (**p < 0.01) and gastric mucus production (***p < 0.001), and decreased the total gastric acid secretion (***p < 0.001). The acute toxicity tests showed that safflower oil (5.000 mg/kg, p.o.) had no effect on mortality or any other physiological parameter. Ecotoxicological tests performed using Daphnia similis showed an EC50 at 223.17 mg/l, and therefore safflower oil can be considered “non-toxic” based on the directive 93/67/EEC on risk assessment for new notified substances by European legislation. These results indicate that the antiulcer activity of Safflower oil may be due to cytoprotective effects, which serve as support for new scientific studies related to this pathology.
Acesso aberto (Open Access)
Síntese e caracterização espectroscópica de compostos de coordenação contendo o ligante dipirido [3,2-f: 2,3-h] quinoxalina 2,3 ditetrazol
(Universidade Federal de São Paulo, 2016-12-19) Ferreira, Rafael Caruba [UNIFESP]; Gonçalves, Norberto Sanches [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
The work had two main lines: an experimental and a computacional one. The experimental work comprehended: synthesis of the liganddipirido [3,2-f: 2?,3?-h] quinoxalina ? 2,3 ditetrazol(dpq-dTzol), synthesis of coordination compounds with Fe(II), Zn(II) , Cu(II) and Ni(II), structural confirmation by nuclear magnetic resonance of 1H and 13C, mass spectrometry, vibrational spectroscopic analysis through infrared, Raman and resonance Raman spectroscopies, and analysis of electronic transition in the UV-Visible spectroscopy. Already the computacional aspect comprehended the use of calculations using the Density Functional Theory with methods B3LYP and M06-2X, essentially to estimate the equilibrium geometries, energies and shapes of molecular orbitals, compute vibrational, electronic and nuclear magnetic resonance spectra. The metal-to-ligand charge-transfer was studied, using the molecular orbitals with the spectroscopic results and we concluded that only the coordination compounds with Fe(II) show this phenomenon. The computing data were compared with the experimental data too.

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