Análise da influência da morfologia porosa de implantes de titânio no processo de crescimento ósseo

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-graduação em Ciências e Engenharia de Materiais, Florianópolis, 2013.O tecido ósseo está sempre suscetível a lesões, causadas por agentes externos ou patologias, onde em alguns casos a intervenção cirúrgica para instalação de implantes se faz necessária. Dentre os biomateriais utilizados como sustentação para a regeneração óssea, os implantes porosos processados a base de titânio apresentam uma combinação de fatores que viabilizam o seu emprego, entre eles, apropriadas propriedades químicas e mecânicas. Além da biocompatibilidade, a caracterização estrutural desses materiais é de relevante importância, pois suas características morfológicas também influenciam o processo de regeneração óssea. Este projeto tem como objetivo principal a caracterização de dois grupos de implantes de titânio com morfologias porosas distintas, além da avaliação do crescimento ósseo em suas fases porosas, uma vez que as amostras foram implantadas em tecidos ósseos de coelhos. As análises estruturais e de quantificação óssea foram realizadas por meio da análise de imagens tridimensionais adquiridas com a microtomografia de raios X. As amostras foram processadas por meio da técnica da metalurgia do pó, usando Titânio puro grau 1 como matéria prima e bicarbonato de amônio como agente gerador de poros. Diferentes granulometrias e proporções dos pós utilizados asseguraram diferenças morfológicas entre os dois grupos de implantes. As amostras foram implantadas em tíbias de coelhos, onde os períodos de permanência no tecido ósseo de 7, 14, 21, 28 e 35 dias foram respeitados para a avaliação do processo osseointegrativo. Foram analisados os parâmetros estruturais de porosidade, tamanho de poros e conexões, número de coordenação, permeabilidade, área superficial e grau de esfericidade dos poros de cada grupo. As correlações investigadas entre a fração de poros ocupada por osso e os parâmetros físicos indicaram a influência da morfologia porosa no processo de reparação óssea. Os resultados encontrados contribuirão para a otimização de biomateriais porosos direcionando o seu processamento para atingir propriedades que melhorem o desempenho dos implantes Bone tissue is susceptible to injuries induced by pathologies or accidents. In some cases, a surgical intervention to implant devices is necessary. Biomaterials are often used as scaffolds to bone recuperation. To be applied as a scaffold, porous titanium implants are a good choice due to their chemical and mechanical properties. Besides the biocompatibility, biomaterial implants must to offer other structural parameters which permit the bone ingrowth process. In this work, two groups of porous titanium implants were processed by powder metallurgy with distinct pore morphology. Pure titanium and ammonium bicarbonate (as pore former) were used in the samples processing. Different quantities and grain sizes of the powders provided different pore morphology for the groups. The implants were introduced into rabbits bone tissues for 7, 14, 21, 28 and 35 days. Therefore, the aim of this work is to characterize the pore phase of the titanium porous implants, and also to quantify the pore fraction occupied by neo-bone formation. The measurements were accomplished by means of X-ray microtomography image analysis. Structural parameters such as porosity, pore size, throat size, interconnectivity, permeability, surface area and pore sphericity were analyzed. The correlations between bone neoformation data and structural parameters indicate the influence of the pore shape on osseointegration process. The results of this work can be useful to improve the porous biomaterial processing

A pore-scale investigation of the effect of nanoparticle injection on properties of sandy porous media

Nanoremediation is a new groundwater remediation technology in which nanoparticles (NPs) are injected into the sub-surface to promote in-situ degradation of aquifer contaminants. Although nanoremediation is an effective process to eliminate contaminants in-situ, its success relies on sufficiently mobile NPs that can reach the contaminated zones and remain there to facilitate chemical degradation of contaminants. Therefore, understanding the main parameters that control the mobility and retention of NPs in saturated porous media is a key component of designing a successful nanoremediation process. This work presents the outcome of a pore-scale study of nZVI NP (zero-valent iron) transport in sandy porous media using the non-destructive 3D imaging technique, X-ray computed micro-tomography (X-ray micro-CT). We investigate the effect of grain size (fine, coarse, carbonate and mixed sand) and composition (carbonate vs sand grains) on the mobility and retention of NPs in sand columns. To achieve this, we used four columns packed with grains of different sizes and compositions. The main contribution of this work is, therefore, to understand the effect of NP injection on the structural and geometric properties of sandy porous media and to identify the main pore-scale mechanisms controlling NP transport and entrapment. Our experiment shows that the pore geometries change because of NP injection. Pore clogging is evidenced through pore size and throat size distribution displaying a shift to the left with a noticeable reduction in pore connectivity in all the columns. The porosity and permeability of the columns studied display significant reduction as result of the NP injection

Calcification in free‑living coralline algae is strongly influenced by morphology: Implications for susceptibility to ocean acidification

Rhodolith beds built by free-living coralline algae are important ecosystems for marine biodiversity and carbonate production. Yet, our mechanistic understanding regarding rhodolith physiology and its drivers is still limited. Using three rhodolith species with different branching morphologies, we investigated the role of morphology in species’ physiology and the implications for their susceptibility to ocean acidification (OA). For this, we determined the effects of thallus topography on diffusive boundary layer (DBL) thickness, the associated microscale oxygen and pH dynamics and their relationship with species’ metabolic and light and dark calcification rates, as well as species’ responses to short-term OA exposure. Our results show that rhodolith branching creates low-flow microenvironments that exhibit increasing DBL thickness with increasing branch length. This, together with species’ metabolic rates, determined the light-dependent pH dynamics at the algal surface, which in turn dictated species’ calcification rates. While these differences did not translate in species-specific responses to short-term OA exposure, the differences in the magnitude of diurnal pH fluctuations (~ 0.1–1.2 pH units) between species suggest potential differences in phenotypic plasticity to OA that may result in different susceptibilities to long-term OA exposure, supporting the general view that species’ ecomechanical characteristics must be considered for predicting OA responses

SARS-CoV-2 in Brazil and Psychosocial Repercussions on Men’s Health: Health Literacy Is Important

This study aimed at analyzing the psychosocial repercussions of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) pandemic on the health of men living in Brazil. For this, we carried out a socio-historical and qualitative study, with the participation of 200 men who answered an online questionnaire. The data collected were processed in the NVIVO12® software, structured by the Collective Subject Discourse method, and analyzed from the epidemic disease theoretical framework proposed by Charles Rosenberg. Our results showed that the SARS-CoV-2 pandemic brought about repercussions of different dimensions that compromised the health of men living in Brazil. The repercussions evidenced were behavioral changes and emergence of new habits due to the pandemic; uncomfortable family situations; impaired affective and sexual relationships; harms in marital relationships; and insecurity and psychological distress. It is important to implement strategies that maximize men’s health literacy, promoting better communication in terms of health, and search for help and suitable information about health/mental health.info:eu-repo/semantics/publishedVersio

Factors Associated with Emotion Regulation in Men with Internet Access Living in Brazil during the COVID-19 Pandemic

Publisher Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland.Objective: to evaluate the factors associated with emotion regulation in men with internet access living in Brazil during the COVID-19 pandemic. Method: an epidemiological survey, conducted with 1015 men. An electronic form was applied containing sociodemographic and occu-pational characteristics, support and coping strategies, as well as emotional and behavioral aspects. Emotion regulation was assessed using the Emotion Regulation Questionnaire. Results: The prevalence values observed were 44.6% for Low Cognitive Reappraisal and of 47.1% for High Emotional Sup-pression. The following factors were identified as associated: (a) with Low Cognitive Reappraisal: being aged 30 years old or more, practicing physical activity, worrying about social distancing and having positive emotions and feelings; and (b) with High Emotional Suppression: being heterosexual, non-white race/skin color, having security support or public administration, not sanitizing food, worrying about lack of physical activity and not having negative emotions. Conclusion: the adoption of emotion regulation strategies was associated with individual, contextual and emotional/behavioral characteristics. Masculinity ideals seem to exert an influence on these relationships.publishersversionpublishe

Psychological Distress in Men during the COVID-19 Pandemic in Brazil: The Role of the Sociodemographic Variables, Uncertainty, and Social Support

Objective: To analyze the relationships between sociodemographic variables, intolerance to uncertainty (INT), social support, and psychological distress (i.e., indicators of Common Mental Disorders (CMDs) and perceived stress (PS)) in Brazilian men during the COVID-19 pandemic. Methods: A cross-sectional study with national coverage, of the web survey type, and conducted with 1006 Brazilian men during the period of social circulation restriction imposed by the health authorities in Brazil for suppression of the coronavirus and control of the pandemic. Structural equation modeling analysis was performed. Results: Statistically significant direct effects of race/skin color ( = 0.268; p-value < 0.001), socioeconomic status (SES) ( = 0.306; p-value < 0.001), household composition( = 0.281; p-value < 0.001), PS ( = 0.513; p-value < 0.001), and INT ( = 0.421; p-value < 0.001) were evidenced in the occurrence of CMDs. Black-skinned men with higher SES, living alone, and with higher PS and INT levels presented higher prevalence values of CMDs. Conclusions: High levels of PS and INT were the factors that presented the strongest associations with the occurrence of CMDs among the men. It is necessary to implement actions to reduce the stress-generating sources as well as to promote an increase in resilience and the development of intrinsic reinforcements to deal with uncertain threats.info:eu-repo/semantics/publishedVersio