Ultraviolet Spectroscopy
Mostrando 1-12 de 172 artigos, teses e dissertações.
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1. Carbon Dots from Pilosocereus gounellei for Fluorimetric Determination of Tannin in Tea Using a Flow-Batch System
In this study, xiquexique (Pilosocereus gounellei) native endemic cactus from the Brazilian semiarid was used for the first time as a natural carbon source (“green precursor”) for the synthesis of highly fluorescent carbon dots (CDs). These CDs were successfully used to develop a fast, low-cost, eco-friendly fluorescence method for the determination of t
Journal of the Brazilian Chemical Society. Publicado em: 2023
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2. Synthesis of Conjugated Molecules Based on Dithienopyrrole Derivatives and Pyrene as Chemosensor for Mesotrione Detection
The conjugated molecules based on pyrene and dithienopyrrole derivatives including 4-(2-ethylhexyl)-2-(pyren-1-yl)-4H-dithieno[3,2-b:2’,3’-d]pyrrole (EP4HP) and 4-(2-ethylhexyl)-2,6-di(pyren-1-yl)-4H-dithieno[3,2-b:2’,3’-d]pyrrole (EDP4HP) have been successfully synthesized via C-H direct arylation reaction. The structures of these conjugated molecul
Journal of the Brazilian Chemical Society. Publicado em: 2022
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3. Photo-Fenton-Based Degradation of Methylene Blue Dye Using Hydroxyapatite Nanoparticles Doped with Fe3O4/γ-Fe2O3
In this study, we evaluated the catalytic properties of hydroxyapatite (HA) nanoparticles (NPs) doped with Fe3O4/γ-Fe2O3 for the degradation of methylene blue (MB) dye using a photo-Fenton process at pH 2.5, 7.0, and 9.0. The HA NPs were characterized using X-ray diffraction, scanning electron microscopy, Fourier-transform infrared spectrometry, Raman spect
Journal of the Brazilian Chemical Society. Publicado em: 2022
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4. Gold Nanorods Capped with Different Ammonium Bromide Salts on the Catalytic Chemical Reduction of p-Nitrophenol
It is known that the reactivity of the nanocatalytic systems is related to the particle size and shape and also to the features of the capping agents on the nanostructures. In this study, gold nanorods (AuNRs) were synthesized by the seed-mediated method using different tetra-alkylammonium bromide salts as capping agents, that are, cetyltrimethylammonium (CT
J. Braz. Chem. Soc.. Publicado em: 2021-06
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5. 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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6. DETERMINAÇÃO DA AUTENTICIDADE DE AMOSTRAS DE AZEITE COMERCIAIS APREENDIDAS NO ESTADO DO ESPÍRITO SANTO USANDO UM ESPECTROFOTÔMETRO PORTÁTIL NA REGIÃO DO NIR
Many instrumental techniques are used to monitor the quality of food products, highlighting near infrared spectroscopy (NIRS). In order to determine the authenticity of 60 commercial oil samples seized by the Espírito Santo state police, this work used a portable spectrometer in the NIR region associated with chemometric tools such as principal component an
Quím. Nova. Publicado em: 20/07/2020
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7. Novel PEG 4000 derivatives and its use in controlled release of drug indomethacin
The insertion of functional groups in polymer compounds may facilitate their interaction with different drugs. PEG polymers are widely used for their low melting point, low toxicity, drug compatibility, and hydrophilicity. They are used as pharmaceutical excipients for the formulation of conventional or modified released drugs and are designed to be upgraded
Quím. Nova. Publicado em: 2020-06
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8. JUDD-OFELT ANALYSIS OF Tb3+ AND UPCONVERSION STUDY IN Yb3+-Tb3+ CO-DOPED CALIBO GLASSES
We report on the study of the spectroscopic properties in Ytterbium-Terbium (Yb3+-Tb3+) co-doped calcium lithium borate (CaLiBO) glasses, with the study’s focus being on the upconversion process. Intensity parameters Ωλ for CaLiBO:Tb3+ are determined by the Judd-Ofelt method to be Ω2 = 15.5 × 10-20 cm2, Ω4 = 1.90 × 10-20 cm2 and Ω6 = 3.69 × 10-20 c
Quím. Nova. Publicado em: 2020-02
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9. Evaluation of the physical and antifungal effects of chlorhexidine diacetate incorporated into polymethyl methacrylate
Abstract This study aimed to evaluate the physical properties and antifungal activities of polymethyl methacrylate (PMMA) acrylic resins after the incorporation of chlorhexidine diacetate salt (CDA). Methodology: First, acrylic resin specimens were fabricated with Vipi Cor® and DuraLay® resins with and without the incorporation of 0.5%, 1.0% or 2.0% CDA.
J. Appl. Oral Sci.. Publicado em: 10/01/2020
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10. Produção, caracterização e avaliação in vitro de partículas de quitosana e hidroxiapatita para substituição óssea
Resumo Objetivou-se desenvolver, caracterizar e avaliar in vitro biomateriais compósitos de quitosana com hidroxiapatita (CHI/HA) para atuarem como substitutos ósseos. As quitosanas de baixa (L-CHI) e média (M-CHI) massa molecular foram previamente caracterizadas por gravimetria, viscosimetria e espectrofotometria ultravioleta. Os compósitos de CHI/HA fo
Cerâmica. Publicado em: 14/11/2019
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11. A Self-Assembled AMF-Responsive Nanoplatform Based on Pillar[5]arene and Superparamagnetic Nanoparticles for Controlled Release of Doxorubicin
An alternating magnetic field (AMF)-stimuli responsive nanodevice based on magnetic nanoparticles (MNP) functionalized with water-soluble carboxylate-substituted pillar[5]arene (CP[5]A), namely MNP-CP[5]A, as a multiplatform for cancer treatment has been designed. MNP-CP[5]A was loaded with doxorubicin (DOX), showing a loading capacity of 9.5 mg g-1. The nan
J. Braz. Chem. Soc.. Publicado em: 24/10/2019
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12. Preparation and Luminescence Properties of Europium(III) Ternary Complex-modified Poplar Wood-based Materials
Inspired by the ultraviolet induced properties of biological materials, we developed fluorescent wood as a new type of functional material which can be applied to anti-counterfeit label technology and wood-emitting artwork. This study discusses the influence of temperature, time, ligand ratio, and reactant concentration on the structure and properties of flu
Mat. Res.. Publicado em: 23/09/2019