Uv B
Mostrando 13-24 de 1508 artigos, teses e dissertações.
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13. CURCUMINA COMO INDICADOR NATURAL DE PH: UMA ABORDAGEM TEÓRICA-EXPERIMENTAL PARA O ENSINO DE QUÍMICA
This paper proposes the development of a simple experiment with easily accessible and low cost materials, enabling its practice with or without laboratory infrastructure, with feasibility for computational theoretical study. On the other hand, the objective of the work is to develop a chemical experiment that demonstrates that the chromophore curcumin (natur
Quím. Nova. Publicado em: 2021-02
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14. Interaction of Pb, Ni and Cd with Aquatic Humic Substances of Amazonian Blackwater Rivers
In this study, the extraction and characterization of aquatic humic substances (AHS) from two blackwater rivers in the Amazon basin was carried out in order to assess the seasonal effects in the AHS structure. In addition, an investigation of the complexing capacities (CC) of the structures containing the metal ions CdII, NiII and PbII was also done. The cha
J. Braz. Chem. Soc.. Publicado em: 2021-02
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15. Blue Glow Sticks: Cinnamic Acids and Arylacrylonitriles with Liquid-Crystalline Properties and Highly Fluorescent
Five new π-conjugated chromophores derived from acrylic acid and acrylonitrile were synthesized and their thermal and photophysical behaviors were analyzed. They were designed and synthesized through Knoevenagel condensations between arylacetylenebenzaldehydes and a methylene group activated from cyanoacetic and malonic acids. The characterization of the ta
J. Braz. Chem. Soc.. Publicado em: 2021-01
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16. Development of a First-Order Derivative UV Spectrophotometric Method for the Assay and Solubility Evaluation of Lamotrigine and Nicotinamide Cocrystals
Pharmaceutical cocrystals are composed of a drug and a coformer and are currently gaining attention due to their possibility of improving drug solubility. Quantitative determination of cocrystals is usually carried out by liquid chromatography method, but an alternative for the same is derivative UV spectrophotometry. Cocrystals of lamotrigine (LAM) were for
J. Braz. Chem. Soc.. Publicado em: 2020-12
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17. Preparation of Fluorescent Carbon-Based Dots from Waste Tire Pyrolysis
The pyrolysis of waste tire has been proposed as an alternative route to its recycling producing residual oils that can be used as fuels. In this work, a physicochemical process to obtain carbon-based dots (CBD) from carbon black (CBL) derivatives of tires is described. For this, the CBL was treated with different acids to produce CBL1 and CBL2 particles sus
J. Braz. Chem. Soc.. Publicado em: 2020-11
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18. Preparation and Characterization of the β-Cyclodextrin Inclusion Complex with Benzbromarone
Benzbromarone (BZB) is a drug that has diuretic activity and is used in the gout treatment. Its therapeutic efficiency is decreased by its low water solubility (11.8 mg L-1) and highly hydrophobic aspect (logP 2.7), which are responsible for affecting its intestinal absorption and bioavailability. BZB inclusion complex (IC) aims at increasing the drug solubi
J. Braz. Chem. Soc.. Publicado em: 2020-08
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19. New Heteroleptic RuII/Diphosphine Complexes with Cytotoxicity against Human Breast and Murine Ascitic Sarcoma 180 Tumor Cells
The preparation, characterization, theoretical calculations and biological application of four RuII complexes with 2-picolinate (pic), 2,2’-bipyridine (bipy) and P-P as ligands [P-P = 1,1-bis(diphenylphosphino)methane (dppm-1), 1,2-bis(diphenylphosphino)ethane (dppe-2), 1,3-bis(diphenylphosphino)propane (dppp-3) or 1,1’-bis(diphenylphosphino)ferrocene (d
J. Braz. Chem. Soc.. Publicado em: 2020-07
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20. Matrix Effects on the Degradation of Gemfibrozil, Hydrochlorothiazide, and Naproxen by Heterogeneous Photocatalysis
The degradation of a pharmaceutical mixture (gemfibrozil, hydrochlorothiazide and naproxen) by TiO2/UV-A in different aqueous matrices was evaluated. The matrix components affected the operational conditions, rate constants, and removal efficiency of the pharmaceuticals, as well as toxicity. For sewage treatment plant effluent, a TiO2 concentration three-fol
J. Braz. Chem. Soc.. Publicado em: 2020-06
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21. Efeito da temperatura nas propriedades fotocatalíticas de filmes finos multicamadas de TiO 2 -CeO 2 obtidos por spin coating
Resumo Filmes finos multicamadas de TiO2-CeO2 foram depositados pelo método de spin coating e calcinados a 500 e 700 °C. Os filmes finos foram caracterizados por difração de raios-X (DRX), microscopia eletrônica de varredura por emissão de campo (MEV-FEG), microscopia de força atômica (MFA) e espectroscopia de reflectância difusa. As propriedades fo
Cerâmica. Publicado em: 2020-06
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22. TD-DFT Analysis of the Dissymmetry Factor in Camphor
The fact that the dissymmetry lgeb (g-factor) of camphor is large has been known for decades, and the interpretation of the observed data has also been known for a long time. However, due to the ability of quantum chemical methods to describe chiroptical phenomena more appropriately, additional approaches based on these methods have been successful employed.
J. Braz. Chem. Soc.. Publicado em: 2020-03
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23. Avaliação de duas rotas de processamento para produção de óxido de molibdênio com adição de cobalto
Resumo Os óxidos de molibdênio são materiais tecnológicos muito interessantes, que apresentam diversos usos industriais. A adição de um segundo metal pode melhorar suas propriedades catalíticas, bem como alterar o comportamento eletrônico. Várias metodologias para adicionar um segundo metal podem ser encontradas na literatura, porém a comparação
Cerâmica. Publicado em: 2020-03
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24. Pigmentos à base de cobalto para aplicação em revestimentos cerâmicos
Resumo Pigmentos inorgânicos foram preparados com estrutura espinélio para aplicações em revestimentos cerâmicos. Pigmentos com composição CoCr2O4 e Co0,8Zn0,2Cr2O4 foram sintetizados por uma rota química usando gelatina de uso farmacêutico como precursor orgânico. Foram investigadas a influência da dopagem e a temperatura de tratamento térmico n
Cerâmica. Publicado em: 2020-03