Influência da variação do módulo de elasticidade na previsão computacional do retorno elástico em aços de alta resistência

Resumo: Os aços avançados de alta resistência (AHSS) têm sido uma das apostas da indústria automotiva para reduzir o peso dos veículos e conseqüentemente reduzir o consumo de combustível. Porém, a sua ampla aplicação na indústria automotiva ainda está limitada devido a desafios na conformabilidade, união de chapas, vida de ferramenta e retorno elástico. O retorno elástico é apontado na literatura como o principal problema que compromete a produção em massa de componentes estruturais com esses aços e que até o momento, são poucas as alternativas disponíveis para solucionar o problema. Nos últimos anos ferramentas computacionais de simulação numérica tem sido empregadas no ambiente industrial para auxiliar na previsão da ocorrência do retorno elástico e na definição dos parâmetros adequados para eliminar ou reduzir sua magnitude. Entretanto, a precisão dos resultados numéricos ainda não conseguiu chegar a um nível satisfatório. A limitação na previsão do retorno elástico em aços AHSS por meio de métodos de elementos finitos (MEF) é atribuída à dificuldade de descrever computacionalmente o comportamento mecânico desses aços durante a deformação plástica. A variação do módulo de elasticidade durante a deformação plástica é apontado como um dos principais causadores da não linearidade do comportamento desses aços. Este trabalho teve como objetivo estudar o comportamento da variação do módulo de elasticidade para melhorar a previsão computacional do fenômeno de retorno elástico na conformação de chapas de aços de alta resistência. O procedimento experimental é divido em partes. Na primeira, é feita a caracterização do comportamento mecânico dos materiais ensaiados. Na segunda, são analisados parâmetros práticos de processo e de ferramenta de embutimento que tenham influência na magnitude do retorno elástico. Na terceira, é analisada a influência de parâmetros computacionais na previsão do retorno elástico. Por fim é proposto um ensaio de dobramento onde a variação do módulo de elasticidade com a deformação plástica é considerada por meio da sub-rotina USDFLD. Nos experimentos práticos foi observada a influencia significativa de alguns parâmetros de processo e de ferramenta na magnitude do retorno elástico. Nos experimentos computacionais foi observada a influência significativa de alguns parâmetros computacionais e a capacidade de melhorar a previsão do retorno elástico por meio da variação do módulo de elasticidade

Avaliaçăo dimensional de implantes sob medida para cranioplastia /

Orientador : Dalberto Dias da CostaInclui bibliografi

Sistema gerenciador integrado ao portal do doador de sangue e plaquetas do HC/UFPR

Orientadora: Andreia de Jesus.Trabalho (graduação) - Universidade Federal do Paraná, Setor de Educação Profissional e Tecnológica, Curso de Tecnologia em Análise e Desenvolvimento de Sistemas

Clinical justification of dental radiology in adult patients : a review of the literature

Although the radiological doses used by dentists are low individually, patients are often exposured to many repeat dental radiographic examinations. The ?routine? use of dental radiography, such as screening of all patients using dental panoramic radiography (DPRs) or a random decision to take a dental radiograph, will inevitable lead to unnecessary patient exposure. The use of Radiographic Referral Criteria has now become a legal requirement for all practitioners following the adoption of European Legislation. All exposures to x-rays should be clinically justified and each exposure should be expected to give the patient a positive net benefit. Recently the European Commission has published guidelines (1) on radiation protection in dental radiology. Guidelines have previously been available in a number of European countries (2,3) and also within the United States (4,5). At the present time, no specific guidelines have been published within Spain. The aim of this review article is to provide the Spanish dentist with guidance as to the appropriateness of different radiographic techniques for a variety of clinical conditions and also the frequency with which they should be taken. It is hoped that this document will act as a useful work tool in daily dental practice

Dexamethasone-Loaded Lipomers: Development, Characterization, and Skin Biodistribution Studies

Follicular targeting has gained more attention in recent decades, due to the possibility of obtaining a depot effect in topical administration and its potential as a tool to treat hair follicle-related diseases. Lipid core ethyl cellulose lipomers were developed and optimized, following which characterization of their physicochemical properties was carried out. Dexamethasone was encapsulated in the lipomers (size, 115 nm; polydispersity, 0.24; zeta-potential (Z-potential), +30 mV) and their in vitro release profiles against dexamethasone in solution were investigated by vertical diffusion Franz cells. The skin biodistribution of the fluorescent-loaded lipomers was observed using confocal microscopy, demonstrating the accumulation of both lipomers and fluorochromes in the hair follicles of pig skin. To confirm this fact, immunofluorescence of the dexamethasone-loaded lipomers was carried out in pig hair follicles. The anti-inflammatory (via TNFα) efficacy of the dexamethasone-loaded lipomers was demonstrated in vitro in an HEK001 human keratinocytes cell culture and the in vitro cytotoxicity of the nanoformulation was investigated

Latanoprost-loaded nanotransfersomes designed for scalp administration enhance keratinocytes proliferation.

Latanoprost (LAT) has been shown to have a hypertrichotic effect, which makes it a promising candidate for alopecia treatments. For the first time, LAT has been encapsulated in nanotransfersomes in order to increase its efficacy. Ex vivo skin biodistribution was studied by confocal laser microscopy both in human scalp and pig skin. Results showed that nanotransfersomes increase the penetration of two different fluorochromes, with similar patterns in both species, compared with fluorochrome solutions containing no nanotransfersomes. Nanotransfersomes were stable under accelerated conditions (40 °C/75% RH) and long-term conditions (25 °C/60% RH) for up to 1 year, with no differences in vesicle size and polydispersity when LAT was loaded. Nanotransfersomes increased the LAT cell proliferation effect in HaCaT cell via MAPK signaling pathway. Collectively, our results demonstrate LAT-nanotransfersomes formulation could be a promising therapy for hair growth disorders

Repurposing Disulfiram as an Antimicrobial Agent in Topical Infections

Antimicrobial drugs applied topically offer several advantages. However, the widespread use of antibiotics has led to increasing antimicrobial resistance. One interesting approach in the drug discovery process is drug repurposing. Disulfiram, which was originally approved as an anti-alcoholism drug, offers an attractive alternative to treat topical multidrug resistance bacteria in skin human infections. This study aimed to evaluate the biopharmaceutical characteristics of the drug and the effects arising from its topical application in detail. Microdilution susceptibility testing showed antibacterial activity against Gram-positive bacteria Staphylococcus aureus and Streptococcus pyogenes. Dermal absorption revealed no permeation in pig skin. The quantification of the drug retained in pig skin demonstrated concentrations in the stratum corneum and epidermis, enough to treat skin infections. Moreover, in vitro cytotoxicity and micro-array analyses were performed to better understand the mechanism of action and revealed the importance of the drug as a metal ion chelator. Together, our findings suggest that disulfiram has the potential to be repurposed as an effective antibiotic to treat superficial human skin infections

Efecto de la variación del diseño en geometrías tpms fabricadas por manufactura aditiva

Additive Manufacturing has become a useful process for producing highly customizable and complex products. DLP technology is employed across fields such as medicine, dentistry, footwear, and safety equipment due to its high resolution in detailing produced parts. Triply Periodic Minimal Surface (TPMS) structures have been studied since the 19th century as curved proposals devoid of sharp corners, thereby hindering crack propagation under mechanical stress. Due to their complexity, their manufacture was previously impossible before the advent of additive manufacturing technologies. Analyzing studies on TPMS structures reveals a lack of defined design parameters and their influence on compression mechanical tests, as well as comparisons between structures. This study aimed to evaluate the most studied TPMS structures gyroid, diamond, and Schwarz P and their design parameters such as cell size and wall thickness, to analyze their behaviors under compression tests. Results indicated that cell size did not show statistical significance, whereas geometry and wall thickness exhibited a strong relationship with calculated elasticity modulus values.A Manufatura Aditiva tornou-se um processo eficaz na fabricação de produtos altamente customizáveis e de grande complexidade. Tecnologia DLP é utilizada desde áreas como medicina e odontologia até a produção de calçados e equipamentos de segurança, devido sua alta resolução nos detalhes das peças produzidas. Estruturas Triply Periodic Minimal Surface (TPMS) são estudas desde o século XIX como proposta de curvas onde não ocorre a presença de cantos vivos, dificultando assim a propagação de trincas quando submetidas a esforços mecânicos. Devido a sua alta complexidade, sua fabricação era impossível até o surgimento de tecnologias de manufatura aditiva. Ao analisar estudos referentes às estruturas TPMS, percebe-se a falta de definição dos parâmetros de design e sua influência em ensaios mecânicos de compressão como também um comparativo entre estruturas. O presente estudo propôs uma avaliação das estruturas TPMS mais estudadas, sendo elas giroides, diamante e Schwarz P e seus parâmetros de design tamanho de célula e espessura de parede, para analisar seus comportamentos quando submetidas a ensaios de compressão. Os resultados obtidos mostraram que o tamanho de célula unitária não apresentou significância estatística, já a geometria e espessura de parede apresentaram forte relação com os valores de módulo de elasticidade calculados.La Fabricación Aditiva se ha convertido en un proceso útil para la fabricación de productos altamente personalizables y de gran complejidad. La tecnología DLP se utiliza desde áreas como medicina y odontología hasta la producción de calzado y equipos de seguridad, debido a su alta resolución en los detalles de las piezas producidas. Las estructuras Triply Periodic Minimal Surface (TPMS) se han estudiado desde el siglo 19 como propuestas de curvas donde no hay presencia de esquinas vivas, lo que dificulta la propagación de grietas cuando están sometidas a esfuerzos mecánicos. Debido a su alta complejidad, su fabricación era imposible hasta la aparición de tecnologías de fabricación aditiva. Al analizar estudios sobre las estructuras TPMS, se observa la falta de definición de los parámetros de diseño y su influencia en pruebas mecánicas de compresión, así como en comparaciones entre estructuras. Este estudio propuso evaluar las estructuras TPMS más estudiadas: gyroid, diamante y Schwarz P, y sus parámetros de diseño, como el tamaño de celda y el grosor de pared, para analizar sus comportamientos cuando se someten a pruebas de compresión. Los resultados obtenidos mostraron que el tamaño de celda unitaria no presentó significancia estadística, mientras que la geometría y el grosor de la pared mostraron una fuerte relación con los valores calculados de módulo de elasticidad

The Efficacy and Biopharmaceutical Properties of a Fixed-Dose Combination of Disulfiram and Benzyl Benzoate

Scabies and hair lice are parasitic diseases that affect human skin and hair, respectively. The incidence and resistances of these infections are increasing. Tenutex® (disulfiram and benzyl benzoate emulsion) is an alternative to standard insecticides to avoid resistances. The aim of the work is to evaluate the transdermal absorption and the in vitro efficacy against scabies and hair lice after different exposition times. Dermatomed human skin was used to assess the dermal absorption using a validated High Performance Liquid Chromatography (HPLC) method. HEK001 keratinocytes were used to evaluate the cytotoxicity of benzyl benzoate. Only benzyl benzoate was able to cross the skin, but it did not show cytotoxicity at any of the tested concentrations. The product efficacy was tested on Psoroptes ovis after direct contact and after administration on sheep skin explants at different contact times. Permethrin/malathion-resistant strains of Pediculus humanis capitis adults and eggs were directly exposed to Tenutex, and the vitality and hatchability, respectively, were evaluated. The anti-scabies study demonstrated that exposure for 6 or 24 h completely eradicated the parasite. The pediculicidal activity of Tenutex exhibited superior efficacy than standard treatment on resistant lice. The positive results obtained suggest that Tenutex® is a good treatment option, especially in drug resistance situations