Comunidades no DSpace
Selecione uma comunidade para navegar por suas coleções
- Campus Samambaia, Campus Colemar Natal e Silva, Campus Aparecida de Goiânia.
Submissões Recentes
Item type: Item , Repurposing HIV protease inhibitors against west nile virus: insights from molecular docking and molecular dynamics simulations(2026) Santos, Renato Douglas dos; Oliveira, Guilherme Colherinhas de; Cardoso, Wesley BuenoWest Nile virus (WNV) is a neurotropic flavivirus lacking approved antiviral therapies. Here, we evaluated the repurposing potential of ten HIV protease inhibitors as inhibitors of the WNV NS2B–NS3 protease using molecular docking followed by molecular dynamics simulations. Structural, energetic, and interaction analyses revealed substantial differences in binding stability under dynamic conditions. Indinavir and Atazanavir consistently showed strong and stable interactions, low structural and positional fluctuations, persistent hydrogen bonding, and favorable binding free energies. In contrast, several inhibitors displayed transient binding despite favorable docking scores. These findings emphasize the importance of molecular dynamics in drug repurposing studies and identify Indinavir and Atazanavir as promising candidates for further experimental evaluation against WNV.Item type: Item , Hydration and molar ratio effects in choline chloride-phenol deep eutectic solvents(2026) Silva, Lucas de Sousa; Oliveira, Guilherme Colherinhas deDeep eutectic solvents (DESs) based on choline chloride and phenol (CCPhe) have attracted increasing attention due to their tunable physicochemical properties and structural versatility. In this work, molecular dynamics (MD) simulations were performed for CCPhe systems at molar ratios of 1:2, 1:3, and 1:4 with water contents ranging from 0 to 30%. Energetic, hydrogen-bond, dielectric, transport, and structural analyses were combined to establish a multiscale description of hydration effects. Hydration promotes a progressive redistribution of stabilization from chloride-phenol and choline-chloride interactions toward chloride-water interactions, accompanied by increased watermediated hydrogen bonding and reduced hydrogen-bond lifetimes. The dielectric constant increases significantly with water content, reaching 15.93 for the 1:4 system at 30% hydration, while the infinite-system Kirkwood factor reveals enhanced cooperative dipolar correlations at high hydration levels. Diffusion coefficients increase by nearly an order of magnitude between dry and highly hydrated systems, indicating substantial mobility enhancement. Radial distribution functions show that hydration modifies the first solvation shell of choline through competitive coordination between chloride and water without altering the characteristic contact distance. These results demonstrate that controlled hydration acts as an effective tuning parameter in CCPhe systems, modulating energetic balance, hydrogen-bond connectivity, collective polarization, and molecular transport in a composition-dependent manner.Item type: Item , Mitigating water effects in humid [Pyr14][TFSI] at electrified surfaces via lithium-salt engineering(2026) Oliveira, Leonardo Bruno Assis; Fonseca, Tertius Lima; Oliveira, Guilherme Colherinhas deIonic liquids (ILs) are attractive electrolytes for next-generation electrochemical devices; however, their hygroscopic nature leads to water uptake, which can reorganize the electrical double layer (EDL), promote interfacial water electrosorption, and contribute to the narrowing of the electrochemical stability window (ESW). In this work, we investigate lithium-salt engineering in humid 1-methyl-1-propylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([Pyr14][TFSI]) using molecular dynamics (MD) simulations at fixed electrode surface charge densities. Corrected potential differences relative to the potential of zero charge (PZC), interaction energies, and number-density profiles of ions and water were systematically analyzed for dry, humid, and Li+-containing ILs. The simulations show that interfacial H2O interacts strongly with polarized electrodes and plays a central role in water-induced EDL restructuring. Upon Li+ addition, water molecules are increasingly coordinated by Li+, reducing the population of free water available for accumulation at electrified interfaces. At low surface charge densities, Li+ addition shifts the corrected potential differences toward those obtained for the dry IL, indicating partial mitigation of water-induced electrostatic screening. At higher polarizations and elevated Li+:H2O ratios, particularly 2:1, the calculated ΔδΦ values exceed those of the dry IL, suggesting an apparent overcompensation of water-screening effects within the classical MD framework. Importantly, the calculated potential differences are interpreted as electrostatic descriptors of EDL polarization and water-screening effects, rather than as direct measures of redox stability or absolute ESW. Overall, these results provide structural and electrostatic evidence that Li+ ions can sequester water and reduce free-water accumulation at electrified interfaces, suggesting that lithium-salt addition may help mitigate water-induced EDL perturbations in humid [Pyr14][TFSI]-based electrolytesItem type: Item , Nerolidol and a zwitterionic surfactant induce membrane rigidity in Leishmania amazonensis and infected macrophages(2026) Borges, Ellyêssa do Nascimento; Silva, Kleber Santiago Freitas e; Cardoso, Éder Jéferson Souza; Gomes, Rodrigo Saar; Lima, Eliana Martins; Mendanha Neto, Sebastião Antônio; Alonso, AntonioSpin-label electron paramagnetic resonance (EPR) spectroscopy revealed that the sesquiterpene nerolidol and the ionic surfactant N-hexadecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (HPS) induce membrane rigidity in Leishmania amazonensis after 24 h of exposure. These compounds exhibit antileishmanial activity with IC50 values of ∼74 µmol L-1 (nerolidol) and ∼10 µmol L-1 (HPS). At concentrations near 1-3 × their IC50 values, both agents caused pronounced membrane rigidity, attributed to lipid peroxidation and/or oxidation of membrane proteins driven by elevated ROS levels promoted by the compounds. Both compounds are active in the parasite's plasma membrane, causing a remarkable increase in fluidity immediately after treatment and throughout the 24h-incubation period of the antiproliferative activity assay, the effect reverts to rigidity. Notably, membrane stiffening was absent in uninfected J774A.1 macrophages, suggesting that nitric oxide production may mitigate oxidative damage. In contrast, rigidity was observed in membranes of Leishmania-infected macrophages, indicating compound-induced oxidative stress in infected host cells. These findings support a membrane-centered mechanism of action for both compounds. The early increase in membrane fluidity may promote ion leakage and depolarization of the parasite plasma membrane, leading to mitochondrial hyperpolarization and enhanced ROS generation, which triggers downstream events, including membrane oxidation and stiffening, which ultimately result in parasite death.Item type: Item , A green sol-gel route to Fe3O4@TiO2−CuO photocatalysts with structural stability, visible-light activity, and magnetic recoverability(2026) Stelzer, Gabriel Bardella; Prescilio, Isabella Cristina; Vasconcelos, Leonardo Gomes de; Bakuzis, Andris Figueiroa; Jacinto, Marcos JoséIn this work, we present the synthesis of a multifunctional Fe3O4@TiO2−CuO photocatalyst, integrating Magonia pubescens plant extract and urea-assisted pH modulation. The as-prepared composite exhibits outstanding visible-light photocatalytic performance, achieving 75% degradation of rhodamine B (RhB, 15 ppm) after 5 h under 100 W LED irradiation and retaining more than 45% activity across four reuse cycles enabled by simple magnetic recovery. Notably, urea-assisted synthesis reduces iron leaching by ∼50%, preserving magnetic integrity and enabling efficient catalyst separation. Comprehensive structural, morphological, and surface analyses (TEM, XRD, XPS, XRF, VSM, ICP, GC−MS) confirm the formation of a robust, magnetically recoverable hybrid with a narrowed band gap of 1.65 eV and enhanced stability. GC−MS analysis revealed progressive mineralization of RhB into lowmolecular-weight intermediates.