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Partição dos ácidos 2,4-diclorofenoxiacético e 4-clorofenoxiacético em sistemas aquosos bifásicos de poli(óxido de etileno), cloreto de colina e água.
No full textPrograma de Pós-Graduação em Química. Departamento de Química, Instituto de Ciências Exatas e Biológicas, Universidade Federal de Ouro Preto.O desenvolvimento de métodos eficientes para detecção e quantificação de poluentes é crucial para o monitoramento de substâncias altamente tóxicas ao ambiente e aos seres humanos. Os pesticidas são exemplos dessas substâncias, exigindo métodos sensíveis e aprimorados para sua detecção e quantificação, frequentemente com o uso de etapas de pré-concentração. Sistemas aquosos bifásicos (SABs) surgem como uma alternativa sustentável e promissora nesse contexto. No presente trabalho, é proposto o estudo da partição de dois pesticidas (ácido 2,4- diclorofenoxiacético (2,4-D) e ácido 4-clorofenoxiacético (4-C)) em SABs formados por poli(óxido de etileno) de massa molar 400 g/mol, cloreto de colina e água, a fim de avaliar o potencial desses sistemas para a pré-concentração de pesticidas. Os estudos de partição foram conduzidos em diferentes condições termodinâmicas, com o objetivo de avaliar os efeitos da concentração dos pesticidas, do comprimento da linha de amarração (CLA), da temperatura e do pH sobre o coeficiente de partição (K) e a porcentagem de extração (%E). Os resultados indicaram que a partição dos pesticidas independe de sua concentração na faixa investigada (50 a 200 mg/kg), sugerindo que o comportamento de partição é determinado pelo balanço das interações intermoleculares dos pesticidas com os componentes das fases, sem efeito significativo de interações pesticida-pesticida. Em todas as condições analisadas, os pesticidas apresentaram maior afinidade com a fase rica em PEG400, sendo o coeficiente de partição (K) dependente do CLA e da temperatura. Verificou-se que o aumento do CLA promove o aumento dos valores de K, enquanto o aumento da temperatura leva à sua diminuição. Os valores de %E variaram entre 80,5 e 87,5% para o pesticida 2,4-D e entre 72,9 e 77,2% para o 4-C. A variação do pH do SAB não afetou a partição dos pesticidas de forma sistemática, sendo o efeito dependente do CLA em que foi investigado. Em todas as condições avaliadas, o pesticida 2,4- D apresentou maiores valores de coeficiente de partição, indicando que uma pequena variação na estrutura química influenciou significativamente as interações dos pesticidas com os componentes das fases.The development of efficient methods for the detection and quantification of pollutants is crucial for monitoring substances that are highly toxic to the environment and to human health. Pesticides are examples of such substances, requiring sensitive and advanced methods for their detection and quantification, often involving pre-concentration steps. Aqueous two-phase systems (ATPSs) have emerged as a sustainable and promising alternative in this context. In the present work, the partitioning behavior of two pesticides (2,4-dichlorophenoxyacetic acid (2,4-D) and 4-chlorophenoxyacetic acid (4-C)) in ATPSs composed of poly(ethylene oxide) (molar mass 400 g/mol), choline chloride, and water was investigated to evaluate the potential of these systems for pesticide pre-concentration. Partition studies were conducted under different thermodynamic conditions to evaluate the effects of pesticide concentration, tie-line length (TLL), temperature, and pH on the partition coefficient (K) and extraction percentage (%E). The results showed that the partitioning of the pesticides is independent of their concentration within the investigated range (50 to 200 mg/kg), suggesting that the partitioning behavior is governed by the balance of intermolecular interactions between the pesticides and the phase components, with no significant pesticide-pesticide interaction effects. Under all tested conditions, the pesticides showed a higher affinity for the PEG400-rich phase, with the partition coefficient (K) being dependent on both TLL and temperature. It was found that increasing the TLL led to higher K values, while increasing the temperature resulted in lower values. The %E values ranged from 80.5 to 87.5% for 2,4-D and from 72.9 to 77.2% for 4-C. pH variation in the ATPS did not systematically affect pesticide partitioning, with the effect being dependent on the TLL at which it was evaluated. In all tested conditions, 2,4-D showed higher partition coefficient values, indicating that a small variation in chemical structure significantly influenced the interactions between the pesticides and the phase components
E quando o familiar e o organizacional se misturam? : um estudo das relações de trabalho do setor hoteleiro de Ouro Preto - Minas Gerais.
No full textPrograma de Pós-Graduação em Turismo e Patrimônio. Departamento de Turismo, Escola de Direito, Turismo e Museologia, Universidade Federal de Ouro Preto.Compreender as relações entre a família e o funcionário dentro de uma empresa familiar é mergulhar em um oceano repleto de bifurcações, possibilidades de fontes e diferentes contextos, desempenhando um papel essencial na construção de saberes e na interpretação dos acontecimentos. A narrativa que antecede o despertar desta pesquisa surge da observação da pesquisadora ao vivenciar a rotina de uma empresa familiar no setor hoteleiro da cidade de Ouro Preto (MG). Esta pesquisa tem como objetivo geral compreender a dinâmica entre família e empresa no contexto das organizações hoteleiras em Ouro Preto (MG). Metodologicamente, trata-se de uma pesquisa descritiva, com abordagem qualitativa, fundamentada em roteiros semiestruturados direcionados aos gestores e aos funcionários mais antigos, justamente por possuírem maior tempo de convivência no ambiente de trabalho nos hotéis e pousadas de gestão familiar, todos localizados no município. As entrevistas foram conduzidas a partir de um roteiro semiestruturado, os dados coletados foram tratados com base na técnica de análise de conteúdo, o que permitiu uma interpretação aprofundada das respostas obtidas. Os principais resultados encontrados se referem à administração familiar como fator determinante que influencia a rotina dos colaboradores, bem como ao paradoxo vivenciado pelos funcionários ao enfrentarem a dualidade de se sentirem parte da família, ao mesmo tempo em que não o são. Destaca-se, assim, a percepção que os funcionários desenvolvem em relação à família empresária: por um lado, sentem-se parte dela, envolvidos por laços de confiança, reconhecimento e pertencimento; por outro, reconhecem a existência de barreiras invisíveis que os excluem das decisões e dos privilégios restritos ao núcleo familiar. Essa tensão permeia o cotidiano dos colaboradores, gerando tanto sentimentos de lealdade e engajamento quanto de frustração e distanciamento.Understanding the relationships between the family and employees within a family business is akin to diving into an ocean full of bifurcations, potential sources, and diverse contexts, playing a crucial role in the construction of knowledge and the interpretation of events. The narrative that precedes the emergence of this research stems from the researcher's observation while experiencing the daily routine of a family-run hotel business in the city of Ouro Preto (MG, Brazil). This study aims, in general, to understand the dynamics between family and business in the context of hotel organizations in Ouro Preto (MG). Methodologically, it is a descriptive study with a qualitative approach, based on semi-structured interview guides directed to managers and long-standing employees precisely because of their extended experience within the work environment of family-managed hotels and inns, all located in the municipality. The interviews were conducted using a semi- structured guide, and the data collected were analyzed based on content analysis techniques, which allowed for an in-depth interpretation of the responses obtained. The main findings relate to family management as a determining factor that influences employees' daily routines, as well as the paradox experienced by staff as they navigate the duality of feeling part of the family while simultaneously not belonging to it. It is noteworthy, therefore, the perception employees develop regarding the family business: on one hand, they feel included, nurtured by trust, recognition, and a sense of belonging; on the other hand, they recognize the existence of invisible barriers that exclude them from decisions and privileges reserved for the family nucleus. This tension permeates the daily lives of employees, generating both feelings of loyalty and engagement, as well as frustration and detachment
Juventudes do campo : interseções entre projetos de vida, trajetórias e a educação agroecológica na Zona da Mata mineira.
No full textPrograma de Pós-Graduação em Educação. Departamento de Educação, Instituto de Ciências Humanas Sociais, Universidade Federal de Ouro Preto.Esta tese analisa a influência da educação agroecológica na conformação dos projetos de vida e nas trajetórias profissionais das juventudes do campo. A pesquisa, de caráter qualitativo, foi desenvolvida por meio de entrevistas em profundidade com jovens do campo, estudantes e egressos/as, e educadores/as das EFAs Paulo Freire e Puris, localizadas na Zona da Mata mineira. A hipótese inicial, de que esse processo educativo contribui para fortalecer o sentimento de vínculo dos/das jovens do campo com o território camponês e influencia na conformação de suas identidades, de seus projetos de vida e trajetórias profissionais, fomentando processos de territorialização da agroecologia e possibilitando a permanência no campo, foi parcialmente confirmada. Os resultados revelam que a experiência formativa por meio da educação agroecológica nas EFAs promove reflexões críticas sobre os modelos de desenvolvimento do campo e contribui para o fortalecimento dos vínculos territoriais e da identidade camponesa entre as juventudes do campo. Observa-se que parte dos/as jovens segue trabalhando como agricultor/a e passam a adotar práticas de manejo sustentável e a protagonizar experiências de territorialização da agroecologia, de toda forma, o manejo convencional predomina. Verificou-se também distinções de gênero nas trajetórias juvenis, em que as mulheres enfrentam maior restrição de oportunidades e menor autonomia, muitas vezes recorrendo à migração para centros urbanos. A maior motivação para saída do campo tem sido a busca pela continuidade dos estudos em cursos superiores. Conclui-se que a educação agroecológica constitui um importante instrumento de resistência e de fortalecimento da identidade camponesa entre as juventudes do campo, mas sua efetividade na promoção da permanência no campo, sucessão na agricultura familiar e na territorialização da agroecologia é limitada pela ausência de políticas públicas direcionadas às juventudes do campo e por desafios impostos pelo modelo hegemônico do agronegócio.This thesis examines the influence of agroecological education on the life projects and professional trajectories of the rural youth. Using a qualitative approach, the study was developed through in-depth interviews with the rural youth, both students and former students, as well as educators of the Paulo Freire and Puris Family Farming Schools (EFAs), located in the Zona da Mata region of Minas Gerais. The initial hypotheses that this educational process contributes to strengthen the young people’s connection to the rural territories and shape their identities, life projects and career paths, while fostering the territorialization of agroecology and enabling them to remain in rural areas was partially confirmed. The findings reveal that agroecological education promotes critical reflections on the rural development models and contributes to strengthen the territorial ties and rural identity among young people. Part of the youth continues working in agriculture, adopting sustainable practices and engaging in agroecological initiatives, although conventional farming remains predominant. The study also identifies gender disparities in the young people’s trajectories, with women facing more limited opportunities and less autonomy, often resorting to migration to urban centres. The primary motivation for leaving rural areas is the pursuit of higher education. In conclusion, agroecological education is a significant tool for resistance and for strengthening rural youth identity, though its effectiveness in promoting rural retention, succession in family farming and agroecological territorialization is constrained by the lack of public policies targeting the rural youth and by the dominance of the agribusiness model
Rastreo del movimiento de pseudopartícula sobre un tamiz.
No full textScreen classification and dewatering are essential processes in ore dressing operations, with their efficiency heavily dependent on the oscillation pattern of the granular medium, which enhances stratification and separation, as well as the coalescence of bubbles and the collapse of interfacial menisci, favoring dewatering. This article focuses on the development of a Bluetooth-enabled device designed to simulate and measure oscillations induced in bulk particles, tackling challenges such as selecting appropriate density, shape, dimensions, and material properties for the device's construction, referred to as a pseudoparticle. The ultimate goal was to provide a low-cost tool capable of helping to optimize the industrial performance of screening, and — as a result — reduce the risks of handling wet bulk materials, reduce the energy impact on subsequent processes and reduce the generation of environmental liabilities.A classificação e desaguamento em peneiras são processos essenciais em operações de beneficiamento de minérios, sendo sua eficiência fortemente dependente do padrão de oscilação do meio granular, que potencializa a estratificação e a separação, bem como a coalescência de bolhas e o colapso de meniscos interfaciais, favorecendo o desaguamento. Este artigo centra-se no desenvolvimento de um dispositivo com Bluetooth, concebido para simular e medir oscilações induzidas em partículas de granel, tendo-se enfrentado desafios como a seleção da massa específica, forma, dimensões e propriedades materiais adequadas para a construção do dispositivo, designado aqui por pseudopartícula. O objetivo final era fornecer uma ferramenta de baixo custo capaz de subsidiar a otimização do desempenho industrial do peneiramento, e — por consequência — reduzir riscos de manuseio de graneis úmidos, diminuir impactos energéticos sobre processos subsequentes e minorar a geração de passivos ambientais
Chronic non‑communicable diseases and poor sleep quality during the COVID‑19 pandemic : an analysis of mediation by anxiety and depression symptoms.
No full textBackground Sleep plays a crucial role in physical and mental health, and its lack is associated with chronic non-communicable diseases (CNCDs). To investigate how anxiety and depression influence this relationship, especially during the pandemic, is essential. Objectives To evaluate the association of CNCDs with sleep quality, and mediation by anxiety and depression symptoms during the COVID-19 pandemic. Design and setting Population-based cross-sectional serological survey of 1,511 adults in the Iron Quadrangle region, Brazil. Methods The exposure variable was CNCDs. The outcome variable was sleep quality evaluated through the Pittsburgh Sleep Quality Index (PSQI). Anxiety and depression symptoms were assessed using General Anxiety Disorder 7 (GAD-7) and Patient Health Questionnaire 9 (PHQ-9), respectively. For testing the mediator factors, the path analysis was conducted. Results Poor sleep quality was found in 52.5% of the population; 23.4% had symptoms of anxiety, and 15.0% of depression. Furthermore, 39.8% reported at least one CNCD, with a maximum of five. In multivariate analysis, we found for each unit increase in the number of CNCDs, the chance of poor sleep quality increases by 39% (OR: 1.39; CI95%: 1.09–1.76). In mediation analysis, the presence of anxiety and depression symptoms explained 6.5% and 36.1% of the association between CNCDs and poor sleep quality, respectively. Conclusions Individuals with CNCDs had poor sleep quality during the COVID-19 pandemic. Furthermore, symptoms of anxiety and depression explained part of the association. Therefore, our study highlights the importance of evaluating the sleep quality and mental health of individuals with CNCDs during pandemics
Development and characterization of innovative nifurtimox formulations as therapeutic alternative for Chagas disease.
No full textChagas disease, caused by Trypanosoma cruzi, remains a neglected tropical disease with limited and often suboptimal chemotherapeutic treatment options. The WHO recommends nifurtimox (NFX) for treating Chagas disease, which, although it is effective in the early stages of infection, has variable efficacy in the chronic phase and induces adverse effects that frequently compromise the continuity of the treatment. This study focused on the development and characterization of innovative lipid-based self-emulsifying drug delivery systems (SEDDSs) and poly(ε-caprolactone) implants containing NFX. The SEDDS formulations modified the NFX release extent and rate. The implant characterization included thermal analysis, X-ray diffraction, thermo-optical analysis, and scanning electron microscopy, confirming the low interaction between NFX and the polymer. In vitro assays demonstrated the enhanced anti-T. cruzi activity of the NFX-SEDDS, with minimal cytotoxicity in mammalian cells. In vivo studies using T. cruzi-infected mice revealed that both formulations effectively suppressed parasitemia, achieving cure rates comparable to those of the standard oral NFX treatment. Additionally, the implants showed improved tolerability and sustained efficacy, delivering a prolonged effect equivalent to 40 oral doses. These findings highlight the potential of these innovative NFX formulations as promising alternatives for treating Chagas disease, particularly in the chronic phase, offering improved adherence and comparable efficacy to the existing therapies
Influence of steam curing on the optimum sulfate content in limestone calcined clay cement (LC3).
No full textLC3 cement reduces carbon dioxide emissions by 40 % compared to Portland cement, substituting 45 % of the clinker with calcined clay and limestone. To ensure optimal performance, gypsum content must be optimized, as the high surface area of additions increases sulfate demand. Curing temperature and time also impacts hydration, phase stability, and mechanical properties, requiring sulfate adjustments. This study investigates how curing parameters influence hydration, microstructure, and performance of LC3 cements to optimize sulfate content. LC3 pastes with up to 3 % extra gypsum were cured at ambient (25 ± 2◦C, Ur>95 %) and steam conditions (40–60◦C, 4–16 hours, Ur>95 %). Results showed that isothermal calorimetry and bound water content alone cannot determine optimal sulfate levels. maximum mechanical strengths were obtained with 2–3 % gypsum, with the influence of temperature predominating over time after 10 hours of curing. At 60◦C, higher sulfate content promoted sulfate adsorption by C-(A)-S-H gel over ettringite formation
Machinability and surface integrity of glass fiber reinforced plastic composite : a review.
No full textGlass fiber reinforced plastic (GFRP) composites, initially developed for home insulation, are now essential in aerospace, automotive, marine, and construction industries due to their lightweight, corrosion resistance, and high mechanical strength. However, their anisotropic and heterogeneous nature, coupled with the abrasive behavior of glass fibers, poses significant machining challenges, including rapid tool wear, surface defects, delamination, and subsurface damage. This review systematically examines recent advancements and strategies to address these challenges across machining methods such as turning, milling, drilling, grinding, and tapping. It highlights the influence of cutting regimes, tool geometries, and advanced coatings on machinability and surface integrity. The review also evaluates the impact of cutting environments, including cryogenic cooling, minimum quantity lubrication, and hybrid machining, on cutting forces, tool wear, chip morphology, and surface quality. A key contribution is the exploration of emerging techniques like vibration-assisted and thermally-assisted machining, alongside computational tools such as finite element modeling, artificial intelligence, and artificial neural networks. These tools optimize machining conditions, predict outcomes, and reduce experimental costs. Promising strategies, including advanced coatings (e.g., PCD, TiN, CBN) and simulation-driven approaches, are identified to enhance machinability. By addressing the complex interplay between machining parameters, ma- terial properties, and surface quality, this article offers a concise framework for improving the precision, effi- ciency, and cost-effectiveness of machining GFRPs, paving the way for optimized processes in next-generation composite materials
Associations between pain intensity and inflammatory profile in women with android and gynoid obesity diagnosed with chronic pain : an observational study.
No full textAbstract: Background: There are different types of obesity, and the metabolic conditions associated with these phenotypes are also heterogeneous. Overweight and obesity are not only associated with pain but are also identified as risk factors for the development of pain. Objective: This study aimed to compare the levels of inflammatory biomarkers, counting of immune cells, and chronic pain between android and gynoid female patients with obesity. Method: Thirty (n = 30) women took part in this study (18 androids, age: 50.61 ± 9.41 and 12 gynoids, age: 50.67 ± 9.45). The participants underwent anamnesis, Visual Numeric Scale (VNS), dual-energy X-ray absorptiometry, and blood sampling for the analysis of leukocytes, C-reactive protein (CRP), and interleukin (IL)-6. Results: The number of total leukocytes in the blood was not different when comparing the android group (6045 μL) with the gynoid group (5230 μL). No differences were observed for neutrophils (3440 μL in android and 3017 μL in gynoid), lymphocytes (2208 μL in android and 2115 μL in gynoid), for monocytes (429.7 μL in android and 392.8 μL in gynoid), andbasophils (17.27 μL in android and 15.41 μL in gynoid). However, there was a significant difference between the number of eosinophils when comparing the android group (137.6 μL) with the gynoid group (204.9 μL), p = 0.04. Although both groups presented CRP values above 0.3 mg/dL—indicative of low-grade inflammation—no statistically significant difference was observed. Similarly, no difference was found in pain intensity between groups, as measured by the Visual Numeric Scale (VNS). Conclusions: Although most inflammatory and pain markers did not differ between groups, the higher eosinophil count in the gynoid phenotype suggests immunological distinctions between obesity types. These findings underline the importance of considering body fat distribution in clinical assessments of inflammation and chronic pain in women with obesity
Jean-Christophe Le Coze and the study of socio technological risks.
No full textJean-Christophe Le Coze has been working for the INERIS National Institute for Industrial Environment and Risks in France for more than 20 years now. He started his career as a safety engineer, but very quickly moved into the human and social sciences. From the beginning of his career, he was brought in with the idea that engineers could incorporate Human Factors in their visions and practices of safety. He then spent almost a year at the Technical University of Delft in the Safety Science Group. After that there was an accident in a French pyrotechnic plant in 2003, and Jean-Christophe Le Coze, in charge of the investigation, wrote a report showing the importance of the Human and Organisational Factors behind this event. It was a moment in France during which high-hazardous plants were questioned and were at the heart of the political agenda in terms of developing adequate regulation. Since then, he has contributed significantly to the advancement of knowledge in the safety area. One of his publications “Thirty years of accidents: the new face of socio-technological risks” was translated into Portuguese and published in 2023. This interview highlights the main concepts of the book and current challenges for accident prevention.Jean-Christophe Le Coze trabalha no Instituto Nacional de Ambiente Industrial e Riscos (Ineris) na França há mais de 20 anos. Começou sua carreira como engenheiro de segurança do trabalho, mas rapidamente migrou para as ciências humanas e sociais. Desde o início de sua carreira, foi introduzido à ideia de que os engenheiros poderiam incorporar os Fatores Humanos em suas visões e práticas de segurança. Ele passou quase um ano na Universidade Técnica de Delft, no Grupo de Ciências de Segurança. Após isso, ocorreu um acidente em uma fábrica de pirotecnia na França em 2003 e Jean-Christophe Le Coze, como encarregado da investigação, escreveu um relatório mostrando a importância dos Fatores Humanos e Organizacionais por trás desse evento. Foi um momento na França em que as plantas industriais de alto risco foram questionadas e estavam no centro da agenda política em termos de desenvolvimento de regulamentação adequada também. Desde então, ele contribuiu significativamente para o avanço do conhecimento na área de segurança. Uma de suas publicações, “Trinta anos de acidentes: a nova face dos riscos sociotecnológicos”, foi traduzida para o português e publicada em 2023. Esta entrevista destaca os principais conceitos do livro e os desafios atuais para a prevenção de acidentes