Publications by authors named "Luiz P da Costa"

This study evaluated the median lethal concentration of silver nanoparticles and their effects in fish tambaqui Colossoma macropomum. Therefore, an acute toxicity assay was carried out in completely randomized design evaluating six different concentrations of silver nanoparticles on blood parameters of tambaqui. The silver nanoparticles were produced by chemical reduction with polyvinyl alcohol (AgNP-PVA).

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Article Synopsis
  • * On average, oysters contained 0.23 microplastics per gram and 1.9 per individual, with the highest concentrations found at sites S1 and S3, while S4 had the least.
  • * The majority of microplastics were PA fibers (91%), and the hepatopancreas and gonads of the oysters had the highest accumulation, leading to recommendations for better regulatory practices to minimize human exposure.
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This study evaluated the neuroprotective effects of the Africanized bee venom (BV) and its mechanisms of action after 6-hydroxydopamine-(6-OHDA)-induced lesion in a mice model. Prior to BV treatment, mice received intrastriatal microinjections of 6-OHDA (no induced dopaminergic neuronal death) or ascorbate saline (as a control). BV was administered subcutaneously at different dosages (0.

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Carbon nanotubes (CN) have been studied to treat spinal cord injuries because of its electrical properties and nanometric dimensions. This work aims to develop a photopolymerizable hydrogel containing CN functionalized with an anti-inflammatory molecule to be used in situ on spinal cord injuries. The CN functionalization step was done using the drug (formononetin).

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Microbial biofilms, structured communities of microorganisms, have been often associated to the infection and bacterial multiresistance problem. Conventional treatment of infection involves the use of antibiotics, being an alternative approach is the use of red propolis, a natural product, to prepare polymer nanoparticles. The aim of the present study was to encapsulate red propolis extract in poly(lactic-co-glycolic acid) (PLGA) nanoparticles for destruction in vitro of pathogenic biofilms.

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Background: The chemical composition of plants used in traditional medicine exhibits biologically active compounds, such as tannins, flavonoids, and alkaloids and becomes a promising approach to treat microbial infections, mainly with drug-resistant bacteria.

Objective: The aim of the present study was to evaluate the hydroethanolic leaf extracts of () and () as antimicrobial potential against clinical isolated and Methicillin-resistant .

Materials And Methods: Hydroethanolic leaf extracts were prepared and characterized by high-performance liquid chromatography/diode array detection, Fourier transform infrared, 1,1-diphenyl-2-picrylhydrazyl, and ultraviolet-visible methods.

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The objective of this work was to study the reduction in the capsaicin toxicity by encapsulation in liposomes. Capsaicin was extracted from peppers and characterized with high performance liquid chromatography (HPLC). We determined the zeta potential, polydispersivity index (PdI) and vesicle size of liposomes.

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A hybrid platform based on ionic liquid-based alkoxysilane functionalized mesoporous silica was applied for the synthesis of supported Pt nanoparticles with peroxidase-like catalytic activity. The positively charged groups (imidazolium) chemically bonded to the surface provide dual-functionality as ion-exchangers to the hybrid material, firstly used for the in situ synthesis of the highly dispersed Pt nanostructures and, secondly, for the immobilization of biological species aiming biosensing purposes. The peroxidase-like catalytic activity of the SiO2/Imi/Pt material was evaluated towards the H2O2-mediated oxidation of a chromogenic peroxidase substrate (TMB), allowing the colorimetric detection of H2O2.

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Imidazolium groups were successfully prepared and grafted on the surface of SBA-15 mesoporous silica. The ion-exchange properties of the functionalized porous solid (SBA-15/R(+)Cl(-)) toward AuCl(4)(-) anions were evaluated through an ion-exchange isotherm. The calculated values of the equilibrium constant (log β = 4.

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Petroleum essentially consists of a mixture of organic compounds, mainly containing carbon and hydrogen, and, in minor quantities, compounds with nitrogen, sulphur, and oxygen. Some of these compounds, such as naphthenic acids, can cause corrosion in pipes and equipment used in processing plants. Considering that the methods of separation or clean up the target compounds in low concentrations and in complex matrix use large amounts of solvents or stationary phases, is necessary to study new methodologies that consume smaller amounts of solvent and stationary phases to identify the acid components present in complex matrix, such as crude oil samples.

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The three-parameter Sips adsorption model was successfully employed to modeled equilibrium adsorption data of a yellow and a red dye onto a mesoporous aminopropyl-silica, in the presence of the surfactant sodium dodecylbenzenesulfonate (DBS) from 25 to 55 degrees C. The results were evaluated in relation to the previously reported surface tension measurements. The presence of curvatures of the van()t Hoff plots suggested the presence of non-zero heat capacities terms (Delta(ads)C(p)).

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