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    Estudo das propriedades de estados excitados de porfirinas: formação de estados tripletos e oxigênio singlete
    (Universidade Federal de Goiás, 2023-08-22) França, Andrew Gabriel Boaventura; Gonçalves, Pablo José; Gonçalves, Pablo José; Souza, Márcio Adriano Rodrigues; Marquezin, Cássia Alessandra
    Photophysics has been gaining more and more importance, both in the academic area and in the technological area. In particular, we highlight its importance in Photomedicine, where photophysical controls are fundamental to explain Photodynamic Therapy, a new therapeutic modality used for the treatment of microorganisms and even tumors. This therapy employs the use of a photosensitizing compound, which in its excited state after absorption of visible light, produces reactive oxygen species that can lead to cell death of specific targets. In this course conclusion work, a study of the dynamics of excited states of organic signals, the main characteristics of excited states of porphyrins and a brief review of the experimental techniques involved for the proper characterization of a photosensitizer compound were carried out.Experimentally, the efficiency of triplet state formation was obtained, analyzing the effects of the concentration of photosensitizers and the concentration of oxygens on the phosphorescence emission of singlet oxygen, one of the main reactive oxygen species involved in the photodynamic action. It was also verified the importance of adjusting the absorption of the sample under study to 0.2 and a time of 20 to 30 minutes of bubbling oxygen for saturation of the solution.
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    Hiperpolarizabilidades das moléculas Li-H3C4N2 · · ·Na2 e Li-H3C4N2 · · ·Ca: comparação entre resultados baseados em teoria do funcional da densidade e coupled cluster
    (Universidade Federal de Goiás, 2023-08-22) Costa, João Victor de Brito; Castro, Marcos Antônio de; Castro, Marcos Antônio de; Fonseca, Tertius Lima da; Osório, Francisco Aparecido Pinto
    Electrides and alkalides are materials with diffuse electrons, consequently presenting applications in several areas os physics. In this work, We present result in calculations of first and second hyperpolarizabilities of the lithium salt electride (Li-H3C4N2· · · Na2) and the calcium-doped lithium salt of pyridazine (Li-H3C4N2· · · Ca). The calculations intend to analyze wheter the density functional theory (DFT) returns good results, so we compared it to the CCSD method. The results obtained using DFT appear to be insufficient when it comes to calculate hyperpolarizabilities of molecules with diffuse electrons.
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    Influência da concentração de nanopartículas de ouro do tipo (AU)144(SRCOO1−)60 em solução: uma análise utilizando dinâmica molecular
    (Universidade Federal de Goiás, 2023-08-16) Bordoni, Giulia Picciola; Oliveira, Guilherme Colherinhas de; Oliveira, Guilherme Colherinhas de; Almeida, Agnaldo Rosa de; Andrade, Douglas Xavier de
    In this study, we investigated the behavior of interactions between functionalized gold nanoparticles (NPs), specifically of the (Au)144(SRCOO1-)60 type, and sodium ions Na{1+) in aqueous solution. These nanoparticles play a crucial role in research on necrosis and mitochondrial damage in several cell lines, and it is essential to understand their ability to insert and penetrate lipid membranes, and how this relates to their charge and surface composition (functionalization). The study was conducted utilizing classical molecular dynamics simulations (MD) in conjunction with developed analytical protocols to assess the impacts of increasing the quantity of nanoparticles in the solution, resulting in a subsequent rise in AuNP concentration. The objective was to investigate how this variation affects the energetic interaction between nanoparticles and ions, the distribution of hydrogen bonds (HBs) formed between nanoparticles and water molecules, the lifetime of these HBs interactions, as well as changes in the spatial arrangement and on the dynamics and mobility of nanoparticles in solution. By exploring these aspects, we seek to understand how increasing the concentration of AuNPs can impact the properties and behavior of these nanostructures in aqueous solution. These insights are relevant to provide a more complete understanding of the interactions of gold nanoparticles in a biologically relevant environment, and may contribute to the development of more effective therapeutic and diagnostic strategies based on nanotechnology.
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    Estudo do mecanismo de ação da atividade leishmanicida da miltefosina
    (Universidade Federal de Goiás, 2023-08-17) Fontenele, Thaís Moreira; Alonso, Antonio; Alonso, Antonio; Mendanha Neto, Sebastião Antônio; Marquezin, Cássia Alessandra
    Miltefosine (MT) is an internationally approved oral drug for the treatment of leishmaniasis, however, its mechanisms of action are not clear yet. In this study, we used electron paramagnetic resonance (EPR) spectroscopy associated with the spin label method to demonstrate that MT causes membrane rigidity in promastigotes of L. amazonensis after treatments of 24, 48 and 72 h. The EPR spectra were consistent with the occurrence of intense lipoperoxidation and oxidation of membrane proteins. These results agree with reported works showing that MT also causes changes in the mitochondrial membrane potential, as well as several compounds that also cause membrane rigidity in the Leishmania parasite. As previous studies have shown that MT causes great fluidity in the parasite's membrane after two hours of treatment, the results of this work suggest that the primary action of MT is on the plasmatic membrane, with probable alteration in the ionic balance, like ivermectin that alters the electrical potential on the parasite membrane and causes membrane rigidity as has been reported.
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    Desenvolvimento de um protótipo auxiliar para pesquisas com plantas em estresse hídrico
    (Universidade Federal de Goiás, 2023-08-16) Mendes, Patrick Soares; Narciso, Marcelo Gonçalves; Paula, Geyverson Teixeira de; Paula, Geyverson Teixeira de; Jesus, Luiz Henrique Reis de; Vieira, Silvio Leão; Narciso, Marcelo Gonçalves
    Climate change has the potential to transform society and the human relationship with the environment. With the growing need for food and climate change already impacting global production, studies warn of possible worrying scenarios if the exploitation of natural resources continues. A crucial solution is to increase agricultural production with efficient use of water to ensure food security. Developing techniques in this direction requires accurate collection of climate, plant and soil data. Indiscriminate and manual collection undermines the reliability of the research carried out. To solve this, embedded systems from the Agro 4.0 network are suitable for automating research processes. At Embrapa Rice and Beans, work is being done on the impact of water stress on plant production, so an auxiliary prototype was proposed, with the ability to collect data such as plant pot weight, water mass loss and soil moisture. A low-cost electronic circuit was developed with the ESP32 microcontroller in order to perform the task. Experiments with cotton plants in a controlled environment were conducted to validate the prototype. Results showed that the sensors selected, device communication and data storage worked properly, including being recorded in a spreadsheet. With adaptations, the prototype has the potential to be improved for external use, monitoring atmospheric pressure, intensity of sun exposure and temperature, among others.