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A study on dynamic non-destructive testing of ground anchorages - dynamic stiffness method.
No full textThis present paper analyzes an anchored retaining wall using a non-destructive dynamic test, which is based on the variation of the dynamic stiffness of the ground anchors, applied to a real case study. The main objective is to evaluate the applicability and particularities of the method to identify the structural integrity of the anchorages, including their free, total and anchored lengths, as well as their current working loads. The results indicated that the dynamic stiffness of the anchorages varied around 5.0E8 N/m, while the working loads found were values between 74.6 kN and 107.9 kN. The analyses performed indicated that the dynamic stiffness of the anchorages did not present large variations along the anchored wall, proving that the determined lengths accurately reflect the real situation of the anchorages. In addition, a very isonomic distribution of forces was obtained, evidenced by the stiffness values obtained. The method stood out for its practicality in execution and analysis of results, consolidating itself as an effective and non-destructive tool for structural evaluation. Despite the general ease of the method, the study reinforces the need for technical experience in the interpretation of specific steps of the procedure, especially in cases with more complex structural behavior. The test proved to be a reliable solution for the continuous monitoring and diagnosis of containment systems, meeting the requirements of normative inspections and contributing to preventive maintenance. Thus, the work reinforces the potential of the method to ensure the safety, structural performance and longevity of anchored walls
Avaliação da eficácia da toxina PnTx4(5-5) para tratamento de dor neuropática induzida por quimioterápico.
No full textPrograma de Pós-Graduação em Ciências Farmacêuticas. Escola de Farmácia, Universidade Federal de Ouro Preto.A dor neuropática induzida por quimioterápicos (DNQ) é o principal e o mais frequente efeito adverso dos tratamentos com agentes antineoplásicos. Atualmente não há fármaco específico para tratamento da DNQ e os fármacos empregados no momento não trazem o alívio completo da nocicepção e podem desencadear efeitos adversos. Por isso, algumas toxinas animais vêm sendo estudadas para tratar a DNQ, como é o caso da toxina PnTx4(5-5). Ela é uma neurotoxina purificada do veneno da aranha armadeira e acredita-se que possui potencial analgésico, já que o peptídeo proveniente do mesmo veneno, a toxina Phα1β demonstrou ser eficaz em um modelo de dor induzida pelo Paclitaxel. Dessa maneira, o objetivo do presente estudo é analisar a eficácia da PnTx4(5-5) no modelo de dor neuropática induzida pelo quimioterápico vincristina e, para isso, padronizou-se o modelo de dor neuropática induzida por quimioterápico em ratos. A avaliação da alodínia mecânica foi realizada por meio do método de up-and- down, e pelo método alternativo, também utilizando os filamentos de von Frey. Para confirmação do efeito antinociceptivo foi construída uma curva de tempo e outra de dose- resposta e, por último, um ensaio comparativo entre a toxina, seu controle positivo o MK- 801 e dois fármacos já utilizados na clínica para tratamento da DNQ, a memantina e a gabapentina. Essas análises resultaram em um limiar de dor reduzido após o protocolo de nocicepção que pôde ser revertido pela administração da PnTx4(5-5) por via i.t., com pico de ação de 2h de sua aplicação e perdurou por cerca de 4h, alcançando uma DE50 de 121,9 (83,72- 177,4 pmol/sítio) com Emax de 87,54 ± 12% para uma dose de 500pmol/sítio. Conclui-se que a toxina é mais eficaz que o MK-80 e a memantina, e mais potente para tratamento da DNQ, porém não é mais eficaz e potente por via i.t do que a memantina e a gabapentina por via i.p para esse modelo de dor e que a toxina pode dar origem a novos fármacos.Chemotherapy-induced neuropathic pain (CINP) is the main and most frequent adverse effect of treatments with antineoplastic agents. Currently, there is no specific drug for the treatment of CINP, and the drugs currently in use do not provide complete relief from nociception and may trigger adverse effects. For this reason, some animal toxins have been studied for the treatment of CINP, such as the toxin PnTx4(5-5). This is a neurotoxin purified from the venom of the armed spider (Phoneutria nigriventer), and it is believed to have analgesic potential, since another peptide from the same venom, the Phα1β toxin, has shown efficacy in a Paclitaxel-induced pain model. Therefore, the aim of the present study is to analyze the efficacy of PnTx4(5-5) in a vincristine-induced neuropathic pain model, and for this purpose, a standardized chemotherapy-induced neuropathic pain model in rats was established. Mechanical allodynia was assessed using the up-and-down method, as well as an alternative method also employing von Frey filaments. To confirm the antinociceptive effect, both a time-course curve and a dose-response curve were constructed. Finally, a comparative assay was conducted between the toxin, its positive control MK-801, and two clinically used drugs for CINP treatment: memantine and gabapentin. These analyses showed a reduced pain threshold after the nociception protocol, which was reversed by intrathecal (i.t.) administration of PnTx4(5-5). Its peak effect occurred 2 hours after administration and lasted approximately 4 hours, reaching an ED50 of 121.9 (83.72–177.4 pmol/site) with an Emax of 87.54 ± 12% at a dose of 500 pmol/site. In conclusion, the toxin is more effective than MK-801 and memantine, and more potent for the treatment of CINP. However, it is not more effective or potent via intrathecal route than memantine and gabapentin administered intraperitoneally (i.p.) in this pain model. Nevertheless, the toxin shows promise as a basis for the development of new drugs
Chitosan nanoparticles enhance the antiproliferative effect of Lapachol in urothelial carcinoma cell lines.
No full textBackgroud/Objectives: Lapachol is a naturally occurring prenylated naphthoquinone with antiproliferative effects. However, its clinical application remains limited due to several factors, including poor water solubility, low bioavailability, and adverse effects. The development of chitosan-based nanoparticles holds promise in overcoming these challenges and has emerged as a potential nanocarrier for cancer therapy, including bladder cancer. The objective of this study was to develop and evaluate the effects of chitosan nanoparticles on bladder tumor cell lines. Methods: The nanoemulsion was prepared using the hot homogenization method, while the chitosan nanoparticles were obtained through the ionic gelation technique. The nanoformulations were characterized in terms of particle size and polydispersity index (PDI) using photon correlation spectroscopy, and zeta potential by electrophoretic mobility. Encapsulation efficiency was determined by ultracentrifugation, and the drug release was analyzed using the dialysis method. The antineoplastic potential was assessed using the MTT assay, and the safety profile was assessed through ex vivo analysis. Cellular uptake was determined by fluorescence microscopy. Results: The study demonstrated that both the chitosan-based nanoemulsion and nanospheres encapsulating lapachol exhibited appropriate particle sizes (around 160 nm), high encapsulation efficiency (>90%), and a controlled release profile (Korsmeyer–Peppas model). These nanoemulsion systems enhanced the antiproliferative activity of lapachol in bladder tumor cells, with the nanospheres showing superior cellular uptake. Histopathological analysis indicated the safety of the formulations when administered intravesically. Conclusions: The results suggest that chitosan nanoparticles may represent a promising alternative for bladder cancer treatment
Eating behavior of a child with avoidant/restrictive food intake disorder (ARFID) : a case study.
No full textDentre os transtornos alimentares, o Transtorno Restritivo/Evitativo (TARE) possui poucos estudos correlacionados a ciência sensorial. Dessa forma, o objetivo foi realizar um estudo de caso sobre o comportamento alimentar de uma criança com TARE, visando à eficácia da abordagem da ciência sensorial no auxílio do tratamento. Foram implementadas intervenções sensoriais com uma criança com TARE, com alimentação restrita somente a um suplemento lácteo. Inicialmente foi realizado reuniões com os responsáveis com aplicação do questionário de identificação e caracterização da seletividade alimentar. Posteriormente, foi elaborado um questionário de frequência alimentar preenchido diariamente e avaliado semanalmente. Com o auxílio do “Baralho da Evitação Alimentar”, foi identificado as emoções que os alimentos provocam, os pensamentos positivos e negativos e a identificação de alimentos em gosto e não gosto. Uma oficina de cupcakes foi realizada para promover a exposição gradual aos alimentos. Os dados obtidos foram analisados por meio de análise de conteúdo de forma descritiva, interpretação sistemática dos dados e por meio de nuvem de palavras. Os resultados mostraram que a exposição gradual e a reestruturação cognitiva através das intervenções sensoriais tiveram efeitos positivos significativos no interesse em alimentos pela criança, saindo de uma dieta restrita para mais de dez novos alimentos consumidos. Sugere-se um entendimento mais detalhado da influência das características sensoriais sobre o TARE, bem como a compreensão dos mecanismos que sustentam o tratamento eficaz dessas pessoas, por meio do cronograma de intervenção sensorial elaborado.Among eating disorders, Avoidant/Restrictive Eating Disorder (AED) has few studies related to sensory science. Thus, the objective was to conduct a case study on the eating behavior of a child with AED, aiming at the effectiveness of the sensory science approach in aiding treatment. Sensory interventions were implemented with a child with AED, with a diet restricted to only a dairy supplement. Initially, meetings were held with the guardians and a questionnaire was applied to identify and characterize food selectivity. Subsequently, a food frequency questionnaire was prepared, completed daily and evaluated weekly. With the help of the “Food Avoidance Deck”, the emotions that foods provoke, positive and negative thoughts and the identification of foods in likes and dislikes were identified. A cupcake workshop was held to promote gradual exposure to foods. The data obtained were analyzed through descriptive content analysis, systematic interpretation of the data and through word clouds. The results showed that gradual exposure and cognitive restructuring through sensory interventions had significant positive effects on the child's interest in food, moving from a restricted diet to consuming more than ten new foods. A more detailed understanding of the influence of sensory characteristics on TARE is suggested, as well as an understanding of the mechanisms that support the effective treatment of these individuals, through the sensory intervention schedule developed
Impactos intempéricos en pelotas de mena de hierro.
No full textClimatic weathering of iron ore pellets during storage and transportation critically compromises their structural integrity. This study evaluates the aging effects over 63 days of outdoor exposure on three pellet types: standard for direct reduction, standard for blast furnace, and with high basicity for blast furnace. Results demonstrate decline in compressive strength across all pellet types, whereas tumbling resistance remained stable. Microstructural analysis revealed increased porosity in pellets for direct reduction, correlating with their greater susceptibility to degradation. Scanning electron microscopy and energy dispersive spectroscopy analyses highlighted the role of microstructural evolution, such as grain growth and silicate redistribution, in mitigating weathering impacts and enhancing compressive strength. The results provide a basis for strategic actions to optimize pellet integrity, storage protocols, and quality control in iron ore processing and steelmaking plants.A degradação de pelotas de minério de ferro por intemperismo climático durante armazenamento e transporte compromete sua integridade estrutural. Este estudo avalia os efeitos do envelhecimento, por 63 dias de exposição ao ar livre, em três tipos de pelotas: padrão para redução direta, padrão para alto forno e com alta basicidade para alto forno. Houve declínio na resistência à compressão em todos os tipos de pelotas, enquanto a resistência ao tamboramento permaneceu estável. A análise microestrutural revelou aumento da porosidade nas pelotas para redução direta, correlacionando com sua maior suscetibilidade à degradação. As análises de microscopia eletrônica de varredura e de espectroscopia de energia dispersiva destacaram o papel da evolução microestrutural, como crescimento de grãos e redistribuição de silicatos, na mitigação dos impactos do intemperismo e no consequente aumento da resistência à compressão. Os resultados permitem balizar ações estratégicas para otimizar a integridade das pelotas, os protocolos de armazenamento e o controle de qualidade em plantas de processamento de minério de ferro e siderúrgicas
Concentração de minério de cobre de baixo teor por transmitância de raios X.
No full textPrograma de Pós-Graduação em Engenharia Mineral. Departamento de Engenharia de Minas, Escola de Minas, Universidade Federal de Ouro Preto.A concentração de minérios sulfetados de cobre de baixo teor pela técnica de particle sorting por transmitância de raios X (DE-XRT) foi estudada em escala semi-industrial, para minérios oriundos de duas minas distintas. Foram realizados 12 testes, com o objetivo de se conhecer os efeitos das variáveis origem do minério, tamanho máximo das partículas e seletividade do equipamento (capacidade do equipamento em priorizar a recuperação em massa do concentrado ou o seu teor de cobre) sobre o desempenho do processo. Os dois minérios estudados foram amostrados na área de estoque de minérios de baixo teor de um complexo industrial em operação e processados em planta construída no mesmo complexo industrial. O equipamento de concentração utilizado foi o Steinert KSS 100 520 MS XT 12U. Foi possível obter concentrados de cobre com teores de até 0,84%, com recuperações de massa variáveis. Os rejeitos de todos os testes apresentaram teores de cobre inferiores ao do material estéril das minas, de 0,20% de cobre. As taxas de processamento variaram de 22,3 t/h a 77,3 t/h, dependendo do tamanho máximo de partícula testado. Os resultados mostraram que a seletividade da concentração por transmitância de raios X é reduzida pela presença de outros elementos pesados nos minerais de ganga do minério, que não o cobre, bem como é impactada pela associação mineral dos sulfetos de cobre. O minério com maior presença de sulfetos disseminados apresentou menor teor de cobre no concentrado e maior teor de cobre no rejeito quando comparado com o outro minério testado, no qual a presença de sulfetos de cobre disseminados é menor.The concentration of low-grade copper sulfide ores using the X-ray transmission particle sorting (DE-XRT) technique was studied on a semi-industrial scale for ores from two different mines. Twelve tests were carried out to determine the effects of the variables ore origin, particle top size, and equipment selectivity (the equipment's ability to prioritize the mass recovery of the concentrate or its copper content) on process performance. The two ores studied were sampled from the low-grade ore stockpile of an industrial complex in operation and processed in a plant built in the same industrial complex. The concentration equipment used was the Steinert KSS 100 520 MS XT 12U. Copper concentrates with grades of up to 0.84% were obtained, with variable mass recoveries. The rejects from all tests had copper grades lower than that of the mine's waste material, which is 0.20% copper. The processing rates varied between 22.3 t/h and 77.3 t/h, depending on the particle top size tested. The results showed that the selectivity of the concentration by X-ray transmittance is reduced by the presence of heavy elements other than copper in the gangue minerals of the ore, as well as being impacted by the mineral association of copper sulfides. The ore with the highest presence of disseminated sulfides had a lower copper content in the concentrate and a higher copper content in the reject when compared to the other ore tested, in which the presence of disseminated copper sulfides was lower
A síntese biográfica e a formulação da experiência da história nacional na Argentina, Brasil e Chile no século XIX.
No full textPrograma de Pós-Graduação em História. Departamento de História, Instituto de Ciências Humanas e Sociais, Universidade Federal de Ouro Preto.A presente tese investiga a relação entre biografia, história e a construção da experiência da história nacional na Argentina, no Brasil e no Chile durante o século XIX, a partir da análise comparada de compêndios biográficos produzidos nesses três países. O objetivo principal é compreender de que modo a narrativa biográfica foi mobilizada como forma de síntese histórica, contribuindo para a formulação de sentidos coletivos sobre o passado e a consolidação simbólica das nações em formação. A hipótese central sustenta que, ao longo do século XIX, a biografia constituiu um dispositivo historiográfico relevante para articular interpretações históricas e valores ético-políticos por meio da representação de personagens exemplares. A tese se desenvolve a partir do estudo de três obras fundamentais: O Plutarco Brasileiro (1847), Galería Nacional [...] de Chile (1854) e Galería de Celebridades Argentinas (1857). A análise dessas fontes revela que diferentes formas de elaboração biográfica correspondem a distintos modos de organizar o passado, variando de relatos mais descritivos à narrativas densas que articulam macroestruturas históricas. Ao posicionar as biografias no cruzamento entre discurso histórico e espaço público, a tese propõe que a biografia foi fundamental na configuração de uma cultura de história moderna na América do Sul e na constituição simbólica das nações, através da articulação de um sentido histórico para a história nacional promovido pela síntese biográfica.This dissertation investigates the relationship between biography, history, and the construction of the experience of national history in Argentina, Brazil, and Chile during the 19th century, based on a comparative analysis of biographical compendiums produced in these three countries. The main objective is to understand how biographical narrative was mobilized as a form of historical synthesis, contributing to the formulation of collective meanings about the past and the symbolic consolidation of nations in formation. The central hypothesis maintains that, throughout the 19th century, biography was a relevant historiographical device for articulating historical interpretations and ethical-political values through the representation of exemplary characters. This dissertation is developed based on the study of three fundamental works: O Plutarco Brasileiro (1847), Galería Nacional [...] de Chile (1854), and Galería de Celebridades Argentinas (1857). The analysis of these sources reveals that different forms of biographical construction correspond to distinct ways of organizing the past, ranging from more descriptive accounts to dense narratives that articulate historical macrostructures. By positioning biographies at the intersection between historical discourse and public space, this study argues that biography played a fundamental role in shaping a modern culture of history in South America and in the symbolic constitution of nations, through the articulation of a historical meaning for national history promoted by biographical synthesis
Gelatin nanofibers coated with hyaluronic acid as a mesenchymal stromal cell scaffold for corneal regeneration.
No full textElectrospun gelatin nanofibers coated with hyaluronic acid (GelNF-HA) were synthesized as a scaffold for delivering human corneal mesenchymal stromal cells (C-MSCs) directly to deep corneal injuries. Aligned GelNFs were produced by electrospinning, crosslinked using vapor of glutaraldehyde, coated with HA, and crosslinked with EDC/NHS. The GelNF-HA was characterized by SEM, mechanical, and optical properties. It was then investigated as a substrate for C-MSC proliferation and migration in vitro and in a rabbit cornea culture model. The expression of α-smooth muscle actin (α-SMA) was determined in the ex vivo model. SEM showed that the GelNF-HA scaffold was composed of aligned GelNFs with 75 % of the fibers oriented against the same angle. It exhibited a Young’s modulus of 1.66 ± 0.59 MPa and approximately 93 % transmittance of visible light. The GelNF-HA membranes supported C-MSC proliferation in vitro. In a scratch migration assay, it facilitated complete wound closure after 48 h in culture. C-MSC-laden GelNF-HA scaffolds supported corneal wound healing in an ex vivo model as well, expressing a lower percentage of stromal α-SMA compared to both the no-treatment keratectomy-only and C-MSC groups (p < 0.05). The C-MSC-supportive GelNF-HA scaffolds hold therapeutic potential for stromal regeneration in the treatment of deep corneal defects
Geochemical analysis of fluvial sediments in the Santo Antônio River Basin, Minas Gerais, Brazil.
No full textA Bacia Hidrográfica do Rio Santo Antônio, situada em Minas Gerais, abrange 29 municípios e abriga cerca de 182 mil habitantes, o que representa 6% da população da porção mineira da Bacia do Rio Doce. Nas últimas décadas, o crescimento populacional e a intensificação das atividades de mineração têm gerado uma série de desafios ambientais, pressionando os ecossistemas locais. Este estudo teve como objetivo realizar um diagnóstico ambiental por meio de análises granulométricas, mineralógicas e geoquímicas dos sedimentos fluviais, a fim de compreender a influência das atividades antrópicas e das formações geológicas nos parâmetros ambientais. Durante uma campanha de campo, foram coletadas 16 amostras de sedimentos em diferentes pontos da bacia. Essas amostras foram submetidas a análise de Difração de Raios X (DRX) e Espectrometria de Emissão Óptica com Plasma Indutivamente Acoplado (ICP-OES). Os dados foram comparados à Resolução CONAMA no 454/2012 e realizou-se também uma análise estatística para identificar os valores de elementos anômalos. Os resultados indicaram que a maior parte dos elementos químicos presentes nos sedimentos tem origem geogênica. No entanto, foram identificadas contaminações por arsênio, cádmio e fósforo, especialmente nas confluências com o Rio Doce (P01 e P03) e em zonas urbanas (P07, P13, P14 e P16). Essas contaminações ressaltam a importância de um monitoramento mais rigoroso por parte das autoridades ambientais, a fim de mitigar os riscos aos ecossistemas aquáticos e à saúde pública.The Santo Antônio River Basin, located in Minas Gerais, spans 29 municipalities and is home to approximately 182,000 residents, representing 6% of inhabitants in Minas Gerais portion of the Doce River Basin. In recent decades, population growth and intensified mining activities have posed significant environmental challenges, putting pressure on local ecosystems. This study aimed to conduct an environmental assessment through granulometric, mineralogical, and geochemical analyses of fluvial sediments to understand the influence of anthropogenic activities and geological formations on environmental parameters. During a field campaign, 16 sediment samples were collected from various points within the watershed. These samples underwent analysis using X-ray diffraction (XRD) and Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The results were compared to the standards established by CONAMA Resolution No. 454/2012, and statistical analysis was conducted to identify anomalous element values. The findings indicated that most chemical elements in the sediments are of geogenic origin. However, contaminants like arsenic, cadmium, and phosphorus were detected, particularly at confluences with the Doce River (P01 and P03) and in urban areas (P07, P13, P14, and P16). These contaminations underscore the need for stricter monitoring by environmental authorities to mitigate risks to aquatic ecosystems and public health
Generalized diffusive epidemic process with permanent immunity in two dimensions.
No full textWe introduce the generalized diffusive epidemic process, which is a metapopulation model for an epidemic outbreak where a non-sedentary population of walkers can jump along lattice edges with diffusion rates DS or DI if they are susceptible or infected, respectively, and recovered individuals possess permanent immunity. Individuals can be contaminated with rate μc if they share the same lattice node with an infected individual and recover with rate μr, being removed from the dynamics. Therefore, the model does not have the conservation of the active particles composed of susceptible and infected individuals. The reaction-diffusion dynamics are separated into two stages: (i) Brownian diffusion, where the particles can jump to neighboring nodes, and (ii) contamination and recovery reactions. The dynamics are mapped into a growing process by activating lattice nodes with successful contaminations where activated nodes are interpreted as infection sources. In all simulations, the epidemic starts with one infected individual in a lattice filled with susceptibles. Our results indicate a phase transition in the dynamic percolation universality class controlled by the population size, irrespective of diffusion rates DS and DI and a subexponential growth of the epidemics in the percolation threshold