https://repositorio.ufu.br/handle/123456789/5095 2026-08-02T06:05:14Z https://repositorio.ufu.br/handle/123456789/49124 Title: Estudo químico de lúpulos cultivados em diferentes localidades por RMN e CLAE - EM/EM e desenvolvimento de um método eletroanalítico para quantificação de iso-α-ácidos em cervejas Abstract: Hops (Humulus lupulus) are a key raw material in beer production, responsible for important sensory characteristics such as aroma and, notably, bitterness. During wort boiling, the α-acids present in hops undergo thermal isomerization to form iso-α-acids compounds directly linked to the beverage's bitterness intensity. In this study, commercial hop varieties were characterized using Nuclear Magnetic Resonance (NMR) and High-Performance Liquid Chromatography coupled with Mass Spectrometry. NMR analysis provided structural information via fingerprints, enabling the identification of major metabolites in the hop extracts, while HPLC-ESI-MS/MS analysis allowed for the annotation of the primary metabolites present in the samples. Specifically, for the Sabro hop variety, the α-acid mixture was separated yielding 31% of the hop extract and subsequently isomerized, resulting in a 42.5% yield of the iso-α-acid mixture. Structural confirmation was achieved through ¹³C NMR spectroscopy; α-acids exhibited a characteristic signal at δ 79.2 ppm, whereas the cis and trans isomers of the iso-α-acids showed signals in the δ 205.1–207.3 ppm range. Subsequently, an electrochemical study using a graphite sheet as the working electrode was conducted to investigate the behavior of iso-α-acids and their relationship to beer bitterness. The voltammetrics profiles obtained for α-acids and iso-α-acids displayed distinct potential regions; consequently, the analysis focused on iso-α-acids, as they are the primary contributors to the beverage's bitterness. Direct analysis of commercial beers revealed the presence of interfering compounds, such as sodium metabisulfite, necessitating sample pre-treatment via isooctane extraction. The efficiency of this procedure was monitored using HPLC-ESI-MS/MS, confirming the presence of iso-α-acids following the extraction step. Finally, bitterness values expressed in IBU were determined using Square Wave Voltammetry; the measured values (BS1 = 48.1; BS2 = 41.6; BS3 = 17.6) were close to those declared by the manufacturers (BS1 = 46; BS2 = 40; BS3 = 18). The results demonstrated that the developed electroanalytical method offers a higher-performance alternative for determining iso-α-acids and for future applications in beer quality control. 2026-07-17T00:00:00Z https://repositorio.ufu.br/handle/123456789/49067 Title: Cosméticos para esmaltação das unhas: uma revisão bibliográfica com ênfase em esmalte tradicional, acrílico e gel uv Abstract: Cosmetic products used for nail coating present complex formulations, composed of different classes of raw materials, selected to provide aesthetics, durability, and performance during application. Among the main products marketed, traditional nail polishes, acrylic systems, and UV-curable gels stand out, each differing in chemical composition, curing mechanism, and potential health risks. Conventional nail polishes are based on nitrocellulose, organic solvents, plasticizers, and pigments, remaining predominant in the market. In contrast, acrylic systems and UV gels use chemically or photo-activated (meth)acrylate monomers and oligomers, providing greater mechanical resistance to the coating. However, these formulations may trigger adverse effects, including allergic contact dermatitis, damage to the nail tissue, and photobiological risks associated with exposure to UV/LED lamps used for gel curing. Therefore, this literature review discusses chemical aspects, polymerization mechanisms, sanitary regulation, and potential toxicological implications, emphasizing the importance of safe application practices and professional qualification in handling these cosmetic products. 2026-03-05T00:00:00Z https://repositorio.ufu.br/handle/123456789/49057 Title: Entre a curiosidade e a docência: memórias de uma trajetória acadêmica Abstract: This academic memorial presents a reflection on my personal, educational, and professional trajectory, highlighting the paths that have contributed to my development as a professor, researcher, extension specialist, and university administrator. Organized into two complementary parts, the text brings together memories, experiences, and academic achievements that have shaped both my personal development and my work in higher education. The first part revisits the people, institutions, and experiences that played a decisive role in my academic and professional formation. It highlights experiences from primary and secondary education, undergraduate studies, master's and doctoral programs, as well as the influence of teachers, family members, friends, and colleagues in shaping my professional identity. It also discusses my first experiences with teaching, research in Science Education and the History of Science, and the experiences that consolidated my interest in teacher education and science education. The second part presents the activities I have carried out at the Federal University of Uberlândia since joining the institution in 2009. It encompasses undergraduate and graduate teaching, student supervision, scientific production, project coordination, initial and continuing teacher education, university extension activities, and academic administration. Particular emphasis is given to my participation in and coordination of institutional programs and research projects funded by public agencies, my work in teacher education initiatives, my contributions to the fields of Chemistry Education and the History of Science, my editorial work for the journal *História da Ciência e Ensino: construindo interfaces*, and my involvement in a wide range of academic and administrative responsibilities. Beyond documenting professional achievements, this memorial seeks to understand the meanings attributed to the experiences accumulated throughout a trajectory shaped by encounters, learning, and a sustained commitment to public education. In revisiting this journey, I aim to demonstrate the inseparability of teaching, research, extension, and academic administration, reaffirming my commitment to teacher education, knowledge production, and the public university as a space for social transformation. Notes: Memorial Descritivo como requisito à promoção para carreira de Titular do Instituto de Química da Universidade Federal de Uberlândia 2026-07-10T00:00:00Z https://repositorio.ufu.br/handle/123456789/49021 Title: As dificuldades enfrentadas por adultos com 30 anos ou mais no curso de Licenciatura em Química da Universidade Federal de Uberlândia Abstract: The mean Brazilian age has increased, just as the need of improvement in many social layers, such as the education field. Because of that increase, there was also a growth in encouraging people to enter Universities, no matter the age. Being so, this assignment will show the profile and the obstacles of the students, who are 30 years old or more, that are / were enrolled in Chemistry Graduation of Universidade Federal de Uberlândia, related with their difficulties and facilities that they found for entering on the Institution later on life. Therefore, 13 students had participated on the data collection and they have answered the questions on Google Forms. The analyses were made based on those answers wanting to understand the reasons that took them to want to enter the University a long time after they have finished High School, by which ways were they able to enroll, which were the difficulties found, just as the facilities, the kind of relationship stablished between the students and the professors, and also with their colleagues, and what could have been done to make the quality of the education of Chemistry Graduation of Universidade Federal de Uberlândia better. With that said, it is concluded that what made the students come back to study was to pursue a better quality of professional and personal life, having the biggest difficulty as to conciliate the job and family with the studies and the biggest facility is referred to be the responsibility with their learning process. 2024-04-24T00:00:00Z