Produção de nanohidrogéis a partir de proteínas do leite

Dissertação de mestrado em Micro-Nano TecnologiasOs nanohidrogéis podem ser incorporados em vários produtos (alimentos, cosméticos e farmacêuticos, por exemplo) com o objectivo de proteger um composto bioactivo ou melhorar as propriedades dos produtos comerciais. Tendo como objectivo a aplicação de nanohidrogéis em alimentos, é necessário que estes sejam formados por elementos edíveis, como as proteínas do leite. O principal objectivo desta tese, foi a formação de nanohidrogéis recorrendo à utilização de proteínas e ao uso de um sal. O cloreto de ferro foi usado como um agente gelificante, essencial na produção dos nanohidrogéis, mas também pelo facto do ferro (carente em muitos seres humanos) possuir a capacidade de se ligar à lactoferrina e poder ser usado como um suplemento alimentar. Para a produção dos nanohidrogéis foram testados vários factores: pH, temperatura de aquecimento, tempo de aquecimento, concentração de proteína e de sal. Após a formação dos nanohidrogéis foi feita a sua caracterização (estudo da estabilidade dos nanohidrogéis ao longo do tempo, ao pH, à temperatura e resistência à liofilização, pela avaliação do tamanho, do índice de polidispersividade e pela carga eléctrica; estudo da morfologia pela Microscopia Electrónica de Transmissão e Microscopia de Força Atómica; estudo da estrutura dos nanohidrogéis pela Espectroscopia de Infravermelhos com Transformada de Fourier e estudo da eficiência de ligação do ferro aos nanohidrogéis). Verificou-se que a formação dos nanohidrogéis é possível através das condições usadas (0,2 % lactoferrina, pH 7, 75 °C, 20 minutos, 0,035 mol/L FeCl3), permitindo uma ligação ao ferro eficaz (cerca de 20 %). Os nanohidrogéis mostraram ser estáveis durante 12 semanas, à temperatura (4 – 60 °C) e ao pH (2 – 11). De uma forma geral, pode-se concluir que os nanohidrogéis desenvolvidos podem ser usados na indústria alimentar.Nanohydrogels can be incorporated into various products (foods, cosmetics and pharmaceuticals, for example) in order to protect a bioactive compound or improve properties of commercial products. With the aim of applying nanohydrogels in food, it’s necessary that they are made of edible components such as milk proteins. The main objective of this thesis was the formation of nanohydrogels through the use of proteins and the use of a salt. Iron chloride was used as gelling agent, which is essential in the nanohydrogels production, but also because of the iron (it lack in many humans) have the ability to bind to lactoferrin and can be used as a food supplement. For nanohydrogels production several factors were tested: pH, heating temperature, heating time, protein and salt concentration. After nanohydrogels formation, it was made their characterization (nanohydrogels stability study over time, pH, temperature and resistance to lyophilization by size, polydispersity index and the electric charge evaluating; morphological study by Transmission Electronic Microscopy and Atomic Force Microscopy; nanohydrogels structure studies by Fourier Transform Infrared Spectroscopy and efficiency study of iron binding to nanohydrogels). It was found that the formation of nanohydrogels is made possible by the conditions used (0.2 % lactoferrin, pH7, 75 °C, 20 minutes, 0.035 mol/L FeCl3), allowing an iron binding effectively (around 20 %). Nanohydrogels shown to be stable for 12 weeks, temperature (4 – 60 °C) and pH (2 – 11). In general, it can be concluded that the nanohydrogels developed can be used in the food industry

Decisão de compra do automóvel para a família : influência dos membros do casal e impacto das características sociodemográficas do elemento feminino

Mestrado em MarketingO poder da família nas decisões tomadas individualmente é um fenómeno amplamente reconhecido. No entanto, com as alterações nas estruturas familiares verificadas nas últimas décadas, analisar e compreender os padrões e dinâmicas de influência da família tem ganho particular atenção. Neste sentido, a presente dissertação procura examinar, para o contexto português, a tomada de decisão de compra, em casal, de um automóvel para a família, analisando as influências relativas exercidas por ambos os cônjuges no processo de decisão e em áreas de decisão específicas, e tentando perceber se as características sociodemográficas do elemento feminino do casal têm impacto nesses padrões de influência. A investigação foi realizada adotando uma abordagem quantitativa e amostragem por conveniência, tendo 178 casais portugueses respondido ao questionário. Através da aplicação do Feasibility Triangle verificou-se que grande parte das decisões, tanto no processo de tomada de decisão como na escolha das características e atributos do automóvel, são tomadas em conjunto, ainda que aquelas que necessitam de experiência e conhecimentos específicos continuem a ser dominadas pelo homem. Os resultados também mostraram que, no geral, as influências exercidas pelos membros do casal estão relacionadas com as características sociodemográficas da mulher. As mulheres jovens, casadas há poucos anos, sem filhos e com maiores recursos económicos e educativos são as mais influentes e decidem mais em conjunto.The power of family in individually made decisions is a widely recognized phenomenon. However, with changes in family structures observed in the last few decades, analyzing and understanding the family's patterns and dynamics of influence has gained particular attention. In this sense, the present thesis seeks to examine, for the Portuguese context, the purchase decision making, by the couple, of a family car, analyzing the relative influences exerted by both spouses in the decision process and in specific areas of decision, and trying to understand if the sociodemographic characteristics of the female element of the couple have an impact on these patterns of influence. The investigation was performed adopting a quantitative approach and convenience sampling, having 178 Portuguese couples answered the questionnaire. Through the application of the Feasibility Triangle it was found that most of the decisions, both in the decision making process and in the selection of the automobile's characteristics and attributes, are made jointly, although those that require experience and expertise continue to be dominated by the husband. The results also showed that, overall, the influences exerted by the members of a couple are related with the wife's sociodemographic characteristics. Younger women, married for a few years, without children and with more economic and educational resources are the most influential and decide more jointly

Impacto dos benefícios fiscais, em sede de IRS, em Portugal e a sua evolução no período de 2001-2010

Mestrado em ContabilidadeOs benefícios fiscais têm sido, por diversas vezes, motivo de discussão, quer em sua defesa, quer alegando a sua extinção. Sendo este um tema actual e relevante, face à conjuntura económica adversa que se vive em Portugal, e que resiste desde meados de 2007, parece ser importante a elaboração de um trabalho de investigação que permita analisar os impactos destes instrumentos de política fiscal, em sede de IRS, na sua génese e aplicabilidade, tanto para o Estado, como para as famílias portuguesas. A evolução, quer ao nível dos benefícios fiscais, quer ao nível das restantes deduções, será analisada atendendo ao período que medeia 2001 e 2010, com base em dados reais e publicados. Pretende-se, assim, responder a três questões: 1 – Em que moldes evoluiu o sistema fiscal português? 2 - Sendo os benefícios fiscais considerados como despesas para o Estado, qual o seu peso face às receitas geradas? 3 - Que fins fiscais e extrafiscais se pretendem alcançar e, de que modo, afectam as pessoas, suas beneficiárias?Tax benefits have been, continuously discussed, either against or in favor their nature. Having in mind the actual adverse economic and financial situation in Portugal, started in 2007, I consider that a deep investigation in a so relevant issue as tax benefits, allowing a wider analysis in its genesis and in its applicability can be important: which are the impacts that arise from their existence for the State’s Public accounts, but also to the Portuguese families. How tax benefits, and other similar tax deductions, have developed will be analyzed for the period 2001 to 2010 (according to statistics and published data). So, it is my intention to answer to the following three questions: 1 – How did Portuguese tax system develop? 2 - Considering Tax Benefits as important State's expenses, what is their real impact? 3 - Tax Benefits, in IRS scope: What is expected to be achieved, beyond financial purposes, to those who benefits?Mestrado em Contabilidad

PERSPECTIVAS DO DIALOGISMO BAKHTINIANO NAS ORIENTAÇÕES CURRICULARES NACIONAIS DE LÍNGUA PORTUGUESA

Este artigo tem por objetivo discutir como o conceito de dialogismo bakhtiniano está presente nas Orientações Curriculares de Língua Portuguesa para o Ensino Médio (OCEM - LP- MEC, 2006), documento reformulado pelo Ministério da Educação em 2006 a partir dos Parâmetros Curriculares Nacionais para o Ensino Médio (PCNEM- LP, MEC, 2000).  Para análise do corpus, tomamos o dialogismo como constitutivo da linguagem, conforme propõe o Círculo de Bakhtin, mais especificamente Bakhtin/Volochinov (2006) e Bakhtin (2003). Esse trabalho se configura como uma pesquisa qualitativa de base interpretativista, de análise de documento e se insere no campo de estudos da linguagem. Os resultados apontam para uma proposta dialógica na perspectiva bakhtiniana em relação ao ensino de língua portuguesa.

Cerâmica islâmica em Portugal: 150 anos

As primeiras referências sobre cerâmica islâmica em Portugal remontam ao final do século XIX. A investigação evolui timidamente até aos anos 80 do século XX, quando se assiste ao incremento dos estudos sobre a temática, impulsionado pelos projectos estruturantes de Mértola e Silves. Nos anos 90, este incremento intensifica-se e, na última década, aumenta o número, a diversidade e a dispersão geográfica de trabalhos e projectos, nomeadamente com origem em arqueologia urbana. O projecto CIGA (Cerâmica Islâmica do Garb al-Andalus), iniciado em 2008, insere-se nesta dinâmica, promovendo a sistematização, problematização e divulgação de toda a informação dispersa e apresentando aqui uma síntese histórica dos estudos sobre cerâmica islâmica em Portugal, suas principais tendências, problemas, virtudes e perspectiva futuras

Lactoferrin-based nanoparticles as a vehicle for iron in food applications: development and release profile

This study aims at developing and characterizing bovine lactoferrin (bLf) nanoparticles as an iron carrier. bLf nanoparticles were characterized in terms of size, polydispersity index (PdI), electric charge (-potential), morphology, structure and stability over time. Subsequently, iron release experiments were performed at different pH values (2.0 and 7.0) at 37 °C, in order to understand the release mechanism. bLf (0.2%, w/v) nanoparticles were successfully produced by thermal gelation (75 °C for 20 min). bLf nanoparticles with 35 mM FeCl3 showed an iron binding efficiency value of approximately 20%. The nanoparticles were stable (i.e. no significant variation of size and PdI of the nanoparticles) for 76 days at 4 °C and showed to be stable between 4 and 60 °C and pH 2 and 11. Release experiments at pH 2 showed that iron release could be described by the linear superposition model (explained by Fick and relaxation phenomenon). On the contrary, the release mechanism at pH 7 cannot be described by either Fick or polymer relaxation behaviour. In general, results suggested that bLf nanoparticles could be used as an iron delivery system for future food applications.Joana T. Martins, Ana I. Bourbon and Ana C. Pinheiro acknowledge the Foundation for Science and Technology (FCT) for their fellowships (SFRH/BPD/89992/2012, SFRH/BD/73178/2010 and SFRH/BPD/101181/2014). This study was supported by FCT under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684). This study was also supported by FCT under the scope of the Project RECI/BBB-EBI/0179/2012 (FCOMP-01- 0124-FEDER-027462). The authors would like to acknowledge Cristina Quintelas and Filomena Costa from CEB, University of Minho for helping with AAS and ICP analysis, respectively. Also, the authors would like to thank Rui Fernandes from IBMC, University of Porto for assistance with TEM analysi

Lung Cavities in Chronic Thromboembolic Pulmonary Hypertension

OBJECTIVES: Chronic thromboembolic pulmonary hypertension (CTEPH) is a unique form of pulmonary hypertension (PH) that arises from obstruction of the pulmonary vessels by recanalized thromboembolic material. CTEPH has a wide range of radiologic presentations. Commonly, it presents as main pulmonary artery enlargement, peripheral vascular obstructions, bronchial artery dilations, and mosaic attenuation patterns. Nevertheless, other uncommon presentations have been described, such as lung cavities. These lesions may be solely related to chronic lung parenchyma ischemia but may also be a consequence of concomitant chronic infectious conditions. The objective of this study was to evaluate the different etiologies that cause lung cavities in CTEPH patients. METHODS: A retrospective data analysis of the medical records of CTEPH patients in a single reference PH center that contained or mentioned lung cavities was conducted between 2013 and 2016. RESULTS: Seven CTEPH patients with lung cavities were identified. The cavities had different sizes, locations, and wall thicknesses. In two patients, the cavities were attributed to pulmonary infarction; in 5 patients, an infectious etiology was identified. CONCLUSION: Despite the possibility of being solely associated with chronic lung parenchyma ischemia, most cases of lung cavities in CTEPH patients were associated with chronic granulomatous diseases, reinforcing the need for active investigation of infectious agents in this setting

Lactoferrin-based nanohydrogel as a vehicle for iron delivery – preparation and release profile

Lactoferrin is a milk protein involved in numerous biological functions, such as regulation and transport of free iron levels, antioxidant and antimicrobial activities. Nanosystems, such as nanohydrogels, may be a vehicle to enrich foods with essential nutrients. Once iron deficit is a major nutritional problem, its inclusion in lactoferrin nanohydrogels could be one of the approaches to improve their stability, protection and subsequent absorption. Moreover, understanding the release mechanisms involved during human consumption, recurring to mathematical modeling, is important for the design of nanohydrogels carriers allowing foreseeing if the developed systems are appropriated to food products. The research conducted aims at developing bovine lactoferrin-based nanohydrogel, and understanding the transport mechanisms of the nanosystem used as iron vehicle. Nanohydrogel were formed by thermal gelation of lactoferrin (0.2 % (w/v)) at 75 °C for 20 minutes. After heat treatment, 35 mM (w/v) of ferric chloride was added. Nanohydrogels were characterized in terms of size distribution, polydispersity index (PDI) and morphology. Release experiments were conducted at different pH (2.0 or 7.0) at 37 o C (simulation of human digestive system conditions). Mathematical models were used to discuss the transport mechanism. Results showed that nanohydrogels with size of 110.0±0.4 nm and PDI of 0.218±0.005 were produced, and were stable during 76 weeks. Data from release experiments at pH 2 were successfully described by linear superimposition model which accounts for both Fick and Case II (polymer relaxation phenomenon) transport; in contrast, transport mechanism at pH 7 cannot be described by either Fick or Case II transport. These results suggest that lactoferrin nanohydrogel system can be used in the food industry as a carrier to facilitate the release of essential nutrients, such as iron, in the human body. Additionally, the approach presented in this work allows interpretation of the phenomena involved in mass transport at the nano-scale

Concurrent agreement between an anthropometric model to predict thigh volume and dual-energy X-Ray absorptiometry assessment in female volleyball players aged 14-18 years

A variety of performance outputs are strongly determined by lower limbs volume and composition in children and adolescents. The current study aimed to examine the validity of thigh volume (TV) estimated by anthropometry in late adolescent female volleyball players. Dual-energy X-ray absorptiometry (DXA) measures were used as the reference method. Total and regional body composition was assessed with a Lunar DPX NT/Pro/MD+/Duo/Bravo scanner in a cross-sectional sample of 42 Portuguese female volleyball players aged 14-18 years (165.2 ± 0.9 cm; 61.1 ± 1.4 kg). TV was estimated with the reference method (TV-DXA) and with the anthropometric method (TV-ANTH). Agreement between procedures was assessed with Deming regression. The analysis also considered a calibration of the anthropometric approach. The equation that best predicted TV-DXA was: -0.899 + 0.876 × log10 (body mass) + 0.113 × log10 (TV-ANTH). This new model (NM) was validated using the predicted residual sum of squares (PRESS) method (R2PRESS = 0.838). Correlation between the reference method and the NM was 0.934 (95%CI: 0.880-0.964, Sy∙x = 0.325 L). A new and accurate anthropometric method to estimate TV in adolescent female volleyball players was obtained from the equation of Jones and Pearson alongside with adjustments for body mass.info:eu-repo/semantics/publishedVersio