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Item Estudo teórico sobre membranas peptídicas e lipídicas: uma análise via dinâmica molecular(Universidade Federal de Goiás, 2021-08-10) Alves, Eyber Domingos; Oliveira, Guilherme Colherinhas de; http://lattes.cnpq.br/0171051425848743; Oliveira, Guilherme Colherinhas de; Castro, Marcos Antonio de; Almeida, Norton Gomes de; Ludwig, Valdemir Eneias; Fileti, Eudes EternoIn this work, the molecular dynamics formalism was used to study the physicochemical properties of peptide and lipid membranes when immersed in solution. Concerningpeptide membranes, the energetic and structural properties were evaluated in the situations in which these membranes were immersed in the Ionic Liquid (IL) formed by the choline (COL) and glycine (GLY) pair. The results indicate the existence of energetic and structural stability of these membranes when in IL, with potential application in energy storage in biodegradable supercapacitors. For lipid membranes, we used the umbrella sampling technique to proceed with a series of 150 insertions of the Fullerene-C 60 molecule in four lipid membranes composed of DOPC (Dipalmitoylphosphatidylcholine) at a ratio of 00% (pure membrane), 10%, 20% and 30% of cholesterol molecules, evaluating the average behavior of molecular insertion energies. The results showed that the presence of cholesterol molecules makes the inclusion process of Fullerene-C 60 energetically unfavorable. Under the computational pathway, we evaluated the pharmacological characteristics associated with monomers constructed based on peptides. For this purpose, we interact the lipid membranes composed of DOPC (Dipalmitoylphosphatidylcholine) at a proportion of 00% (pure membrane), 10% and 30% of cholesterol molecules with the peptide drug L-GL13K. The results reveal that the hydrogen bonds between the compound L-GL13K and the DOPC molecules promote membrane destabilization and increasing the infiltration of water molecules.Item Versatilidade estrutural de aminoácidos agregados: design de nanomateriais orgânicos via dinâmica molecular(Universidade Federal de Goiás, 2022-02-25) Andrade, Douglas Xavier de; Oliveira, Guilherme Colherinhas de; http://lattes.cnpq.br/0171051425848743; Oliveira, Guilherme Colherinhas de; Cruzeiro, Vinícius Wilian dias; Fonseca, Tertius Lima da; Ludwig, Valdemir Eneias; Georg, Herbert de CastroIn this work, we carried out structural and energetic characterization of nine nanomembranes and two nanofibers composed of surfactant-like peptides (SLPs), using Molecular Dynamics (MD) simulations with atomistic resolution. The nanomembranes [nanofibers] studied are formed by the peptides I3V3A3G3K3 and K3G3A3V3I3 [G3A3V3I3K3 and K3I3V3A3G3]; A6Hε and A6Hδ; and I3XGK (X = Q, S, N, G or L). The nanomembranes I3V3A3G3K3 and K3G3A3V3I3 are formed by the same amino acids, but linked in inverted primary sequences, which changes torsions, the side chains, and the C and N peptide terminals, affecting the hydration and stability of the nanomembranes. The A6Hε and A6Hδ nanomembranes are differentiated by the position of the hydrogen atom attached to the aromatic ring of histidine (H) residues, alterning the way that this residue is exposed to water, and consequently, the lateral attachment of alanine residues (A). By studying the I3XGK (X = Q, S, N, G or L) nanomembranes, we realized that the peptides with polar residues (X = Q, S, or N) present properties of polar zippers connecting β-sheets laterally. Therefore, this work aims at elucidating and characterizing the formation of polar zippers that, recently, have attracted significant scientific and technological interest. The nanofibers G3A3V3I3K3 and K3I3V3A3G3 are formed by peptides with the same amino acids, but linked in inverted primary sequences, similar to the case of the nanomembranes I3V3A3G3K3 and K3G3A3V3. This way, by studying nanomembranes and nanofibers composed with the same amino acids, this work allows us to understand how changes in the disposition of the peptide side chains lead to the formation of distinct nanostructures, evidencing the structural versatility of aggregate amino acids. The analyses performed are based on the mass density profiles, on nanomembrane thicknesses, on the radial distribution functions, g(r), on the average number of Hydrogen Bonds (HBs) between amino acids and between each amino acid and water molecules - for a better characterization of HBs between peptides and consequently the nanomembranes’ hydration, HB’s time correlation functions are presented - and in the Coulombic and vdW energetic interactions which together with the HBs play a fundamental role in the organization of the peptides forming the nanostructures. Our results indicate that the C-terminal attached to the charged lysine (K) leads to the formation of more hydrated nanomembranes; the A6Hε and A6Hδ are nanostructures with a high degree of organization and with features of crystalline structures; the polar zippers present an interesting route for the design of robust and stable nanostructures, by joining neighboring β-sheets; the peptide nanostructures presented in this work have interesting characteristics suggesting that they can be used to encapsulate and transport drugs, as hydrogels and as an antimicrobial agent. Our MD results show excellent agreement with experimental data reported in the literature. In addition, we show that the CHARMM36 force field could be recommended for the study of the peptide nanomembranes and nanofibers presented. This validation is important because it allows the prediction from the theoretical point of view of new features of peptide structures of this species, providing advances in the development of organic nanostructures.Item Eficiência de um motor térmico de Otto quântico baseado em um sistema de dois níveis(Universidade Federal de Goiás, 2021-12-09) Assis, Rogério Jorge de; Almeida, Norton Gomes de; http://lattes.cnpq.br/3182841849332242; Almeida, Norton Gomes de; Serra, Roberto Menezes; Cardoso, Wesley Bueno; Brito, Frederico Borges de; Pinto, Diogo de Oliveira SoaresClassical thermodynamics, also called equilibrium thermodynamics, is a theory that deals with macroscopic systems in equilibrium. After its development, other theories emerged to encompass macroscopic out-of-equilibrium systems. Over the past few decades, researchers have developed a new theory to describe also the thermodynamics of microscopic quantum systems, which became known as quantum thermodynamics. An important application of this theory is in the development of heat engines in which the working substance (the substance responsible for transforming heat into work) is a microscopic quantum system. Due to their composition, these devices came to be commonly called quantum heat engines. Notably, recent studies have shown that using an out-of-equilibrium reservoir as a heat source can improve the performance of quantum heat engines, compared to the usual case where the heat source is an equilibrium reservoir (a thermal reservoir). In this context, this thesis presents two studies related to a quantum Otto heat engine whose working substance is a two-level system: in the first study, the engine has a squeezed thermal reservoir as the heat source, while in the second study, the heat source is a reservoir with a negative temperature. Both studies explore the finite-time regime of the expansion and compression stages of the heat engine. The first study shows that the engine efficiency can be greater than the Carnot efficiency in both the quasi-static and finite-time regimes. However, as in the usual case, decreasing the time of the expansion and compression stages degrades the engine efficiency. In its turn, the second study shows that the engine efficiency can surpass the Otto efficiency in the finite-time regime. Here, different from the usual case, decreasing the time of the expansion and compression stages can increase the engine's efficiency. Finally, the present thesis shows an experimental scheme in the nuclear magnetic resonance context able to provide a proof of concept for the engine in the different situations studied.Item Estudo das interações de porfirinas com sistemas de interesse biológico: potencial uso no transporte de fármacos e aplicação fotodinâmica(Universidade Federal de Goiás, 2019-08-23) Bezerra, Fábio de Castro; Gonçalves, Pablo José; http://lattes.cnpq.br/0515343409614452; Gonçalves, Pablo José; De Boni, Leonardo; Iglesias, Bernardo Almeida; Borissevitch, Iouri; Alonso, AntonioThe purpose of this work was to study the interactions of porphyrins in systems of biological interest aiming at drug transport and photodynamic applications. Interactions of anionic meso-tetrakis(p-sulphonatephenyl) porphyrin (TPPS4) and cationic meso-tetrakis (4- methyl-pyridyl) porphyrin (TMPyP) porphyrins with bovine serum albumin (BSA), antibodies, DNA and biocompatible nanoparticles of maghemite were evaluated. To obtain the binding constants and thermodynamic parameters, spectroscopic UV/Vis absorption and fluorescence techniques were used. Binding constants indicate a higher affinity of porphyrin TPPS4 for proteins compared to TMPyP. Thermodynamic parameters showed that electrostatic and hydrophobic interactions mediated the BSA interactions with the porphyrins TPPS4 and TMPyP, respectively. On the other hand, the nature of porphyrin-antibody interactions shows a behavior opposite to that observed for BSA (electrostatic for TMPyP and hydrophobic for TPPS4), indicating that the binding site of porphyrin TMPyP in the antibodies is likely to have a net negative charge. In the porphyrin TPPS4 interaction with maghemite nanoparticles, besides obtaining the binding parameters of the interaction, it was possible to estimate the number of 21 porphyrins coupled in each nanoparticle. Regarding the interaction of DNA with the porphyrins TPPS4, TMPyP and its complexes with zinc, it was observed that ZnTMPyP has higher affinity for DNA than TMPyP, whereas TPPS4 and ZnTPPS4 do not bind to DNA, which explains the results of photodegradation of DNA by these porphyrins. Keywords: PhotodynamicItem Markov monogamy inequalities(Universidade Federal de Goiás, 2022-03-09) Capela, Matheus; Araújo, Rafael Chaves Souto; ttp://lattes.cnpq.br/1509277905143351; Céleri, Lucas Chibebe; http://lattes.cnpq.br/6630683190018665; Celeri, Lucas Chibebe; Avelar, Ardiley Torres; Oliveira, Thiago Rodrigues de; Santos, Marcelo Paleologo Elefteriadis de Franca; Pinto, Diogo de Oliveira SoaresO estudo dos limites na comunicação com canais ruidosos é um problema central na teoria de informação. Data processing inequalities são de fundamental importância sob esta perspectiva. Entretanto, estas não são as as únicas condições existentes sob o processamento de informação. Neste trabalho, apresentamos uma nova categoria de condições chamadas Markov monogamy inequalities. Estes novos resultados são aplicados ao estudo e caracterização de processos não-Markovianos clássicos e quânticos. De grande importância, as condições Markov monogamy inequalities revelam-se serem mais eficientes que as data processing inequalities na certificação de processos não-Markovianos em determinados exemplos.Item Stability and aromaticity of small neutral and charged boron clusters: a quantum Monte Carlo study(Universidade Federal de Goiás, 2019-07-26) Moreira, Emanuel Melo Isaac; Silva, Ladir Cândido da; http://lattes.cnpq.br/7442411485710574; Silva, Ladir Cândido da; Oliveira, Marcos Cesar de; Oliveira, Heibbe Cristhian Benedito de; Oliveira, Guilherme Colherinhas de; Vale, Renato PessoaNeste trabalho, investigamos as energias de ligação eletrônica dos clusters de boro neutros Bn, com n = 3 até n = 13, seus ânions e cátions, usando uma combinação dos métodos, Monte Carlo quântico na aproximação dos nós fixos (FN-DMC), teoria do funcional da densidade e Hartree-Fock. As energias de ligação eletrônica como adiabatic detachment energy, vertical detachment energy, adiabatic ionization potential e vertical ionization potential foram examinadas para diferentes isômeros, e os valores obtidos estão em excelente concordância com resultados disponíveis na literatura, indicando que as geometrias dos clusters de boro, obtidas neste trabalho, estão corretas. A decomposição dessas energias de ligação eletrônica em três componentes físicas como, o potencial eletrostático e a interação de exchange, a energia de relaxação, a qual inclui a relaxação da geometria e dos orbitais, e a correlação eletrônica, nos permitiu determinar que os clusters de boro neutros são estabilizados pelas interações eletrostática e de exchange, enquanto os clusters aniônicos são estabilizados pela energia eletrostática e exchange, energia de relaxação e efeitos de correlação eletrônica. Também investigamos a aromaticidade de pequenos clusters de boro com três e quatro átomos através de princípios de estrutura eletrônica e energia de ressonância. Os resultados FN-DMC aplicados aos princípios de estrutura eletrônica para a energia, hardness e electrophilicity suportam a aromaticidade dos clusters B3-, B4- e B4 , e parcialmente suportam a aromaticidade dos clusters B3 , B3+ e B4+. Os valores obtidos para a energia de ressonância dos clusters B3, B3-, B3+, B4, B4- e B4+ foram: 55.1(7), 54.2(8), 33.9(7), 84(1), 67(1), and 58(1) kcal/mol, respectivamente. Então, a ordem decrescente de estabilidade do trímero é B3- > B3 > B3+, enquanto que paro o tetrâmero é B4 > B4+ > B4- , o que está de acordo com resultados de análise de orbitais.Item Simulação da razão de carga de múons atmosféricos utilizando o CORSIKA(Universidade Federal de Goiás, 2023-10-18) Paulo Júnior, Ademar; Gomes, Ricardo Avelino; http://lattes.cnpq.br/6538341799051577; Gomes, Ricardo Avelino; Peixoto, Carlos José Todero; Valdiviesso, Gustavo do Amaral; Tognini, Stefano Castro; Braghin, Fábio LuisThe muon charge ratio, $R_{\mu} = N_{\mu^{+}}/N_{\mu^{-}}$, is a quantity that can be measured both at at different altitude levels from Earth's surface and in underground experiments. The muons result from the hadronic interactions developed in extensive air showers (EAS) created from the interaction of cosmic rays with nuclei in the atmosphere. The muon charge ratio allows obtaining important information both from the point of view of physics involving cosmic rays, and from the study of the ratio between neutrinos and antineutrinos, $\nu/\bar{\nu}$, since their production is directly connected to the muons. The present work is a study using Monte Carlo simulations of EAS produced by cosmic rays with energy between 100 and $10^{6}$ GeV generated by CORSIKA, using the high energy hadronic interaction models: QGSJETII-04, EPOS -LHC, DPMJET III, SYBILL 2.3c, VENUS and QGSJET01-C. EAS were simulated separately with protons as primaries and He nuclei, and these datasets were combined in the performed analyses. Simulations aimed to verify which one of these hadronic interaction models are able to reproduce the expected behavior for the energies involved considering the increase of $R_{\mu}$ due to the contribution of the kaons to the EAS. It was observed that, to the set formed by protons and He nuclei, with the exception of DPMJET, the other models reproduce an increase in $R_{\mu}$ as a function of the energy of the muons on the surface $E_{\mu }\cos\theta^{*}$. However, when compared to the data obtained in the MINOS, OPERA and CMS experiments, the results, in general, does not reproduce the increase in $R_{\mu}$. Our results show that it would be useful to improve these models so that they can reproduce the expected behavior of the muon charge ratio.Item Cerâmicas multifuncionais de oxido de zinco dopadas com cobalto: propriedades ópticas, dielétricas e magnéticas(Universidade Federal de Goiás, 2019-10-23) Silva, Hermínia Veridiana dos Santos Pessoni e; Franco Júnior, Adolfo; http://lattes.cnpq.br/0187547195548392; Franco Júnior, Adolfo; Machado, Fernando Luis de Araujo; Silva, Sebastião Willian da; Bufaiçal, Leandro Felix de Sousa; Rosa, Andreia Luisa daIn this work, Zinc oxide Cobalt-doped ceramics (Zn1−xCoxO) were produced with 0,00≤x≤0,05 molar concentrations to obtain multifunctional materials. The Solid State Reaction with slow pressing step and maximum sintering temperature of T=1150ºC was used. Structural characterization by Apparent Density (ρap), Energy Dispersion Spectroscopy (EDS), X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) indicated formation of typical ZnO hexagonal wurtizite phase for all samples (space group - P63mc (C6v)), without formation of spurious phases and good stoichiometric measured coherence. The results also indicated good densification for the ceramics (ρrel=97−91%). The optical characterizations performed by Infrared (FTIR), UV-Vis and Raman allowed the observation of the characteristic vibrational modes of ZnO and the confirmation of the total introduction of Co ions in the tetrahedral sites in the lattice, it also allows the study of evolution in the defects’ amount of VO and Zni type and systematic reduction of optical bandgap Eg due to doping. Electrical characterizations performed by Dielectric Permittivity Spectroscopy (EPD) and Impedance revealed Colossal Dielectric Permittivity (PDC) behavior in all samples (ϵ’~105) and, doping intensifies the effect. The overall dielectric behavior of ceramics is consistent with the Maxwell-Wagner (MW) dielectric relaxation model, which was also used to explain the PDC phenomenon. Magnetic characterizations performed using Magnetic Hysteresis, Zero Field / Field Cooling (ZFC / FC) and Electronic Paramagnetic Resonance (EPR) measurements indicated diamagnetic ordering (DM) in the pure sample and predominant paramagnetic (PM) ordering in the doped samples, as well antiferromagnetic ordering (AFM) in doped samples due to the approximation of Co ions in the lattice (sample x=0,05 - 62%PM×38%AFM). Weak Co-ion spin-orbit coupling has been identified in the presence of the ZnO crystalline field. Non-occurrence of ferromagnetism (FM) was discussed in terms of the defects’ placement in ZnO samples.