Produção de quitosano e desenvolvimento de novos materiais a partir de resíduos alimentares

Dissertação para obtenção do Grau de Doutor em Ciência e Engenharia dos MateriaisO quitosano é actualmente um dos biomateriais com maior potencial de resposta às exigências do mercado biomédico. O facto de existir uma panóplia de aplicações para a quitina e seus derivados leva a considerar este polímero como aspirante a biomaterial do século XXI. A quitina e o seu derivado desacetilado, quitosano, são polímeros naturais compostos por unidades monoméricas de β-(1-4)-D-glucosamina (unidade desacetilada) e por N-acetil-D-glucosamina (unidade acetilada). A quitina é insolúvel em meio ácido enquanto o quitosano é solúvel nessas condições devido aos grupos amina protonados livres presentes nas unidades D-glucosamina. A procura desta matéria prima tem crescido substancialmente principalmente pelo seu potencial no desenvolvimento de dispositivos médicos. No presente trabalho procurou-se desenvolver novos materiais com este fim, aproveitando o facto de o quitosano poder formar estruturas liquidas cristalinas e assim mimetizar a organização peculiar do colagénio, um dos principais componentes do tecido humano. A aplicação destas soluções originou o desenvolvimento de um cimento ósseo totalmente biocompatível. A formação de nanofibrilas de quitina, constituiu ainda alvo de estudo pelo seu potencial de reforço de estruturas compósitas com polímeros termoplásticos

Nomofobia: um problema emergente do mundo moderno

O termo nomofobia ou nomophobia em inglês, é uma abreviação de “No Mobile Phone Phobia” e consiste numa condição psicológica em que as pessoas sentem medo de estarem afastadas de seus smartphones ou de estarem desligadas da conectividade proporcionada por eles. A prevalência global da nomofobia é de cerca de 70% para casos moderados a graves e 20% para casos graves, sendo os estudantes universitários e adultos jovens os grupos mais afetados por esta condição. Nesse contexto, objetivo do presente estudo foi analisar e elucidar aspectos importantes acerca da nomofobia no cenário mundial atual. Para a elaboração dessa pesquisa, foram realizadas buscas em bases de dados e selecionados inicialmente 28 artigos, dentre os quais 13 se enquadraram nos critérios pré-estabelecidos. Após uma rigorosa análise da literatura, concluiu-se que a nomofobia é um problema de saúde pública emergente globalmente e que pode acarretar em diversos malefícios para seus portadores, dentre eles uma importante ansiedade e irritabilidade

Microencapsulation of <i>Cymbopogon citratus</i> D.C. Stapf Essential Oil with Spray Drying: Development, Characterization, and Antioxidant and Antibacterial Activities

This study aimed to microencapsulate Cymbopogon citratus essential oil (CCEO) with spray drying using maltodextrin and gelatin. The effects of the operational conditions (inlet temperature (130–160 °C), CCEO concentration (5–15%), maltodextrin concentration (10–20%)) on the physicochemical stability and antioxidant and antibacterial activities of the CCEO microcapsules were determined. The CCEO microencapsulation process had yield and encapsulation efficiency values varying from 31.02 to 77.53% and 15.86–61.95%, respectively. CCEO microcapsules had antibacterial effects against Staphylococcus aureus and Escherichia coli with minimum inhibitory concentration varying from 10 to 20%, and total phenolic contents and antioxidant activities varying from 1632 to 4171.08 μg TE/g and 28.55–45.12 µg/g, respectively. CCEO microcapsules had average diameters varying from 5.10 to 10.11 µm, with spherical external structures without cracks and apparent pores. The best desirable process conditions for CCEO microencapsulation were process inlet temperature of 148 °C, maltodextrin concentration of 15%, and CCEO concentration of 10%. The results showed that CCEO microcapsules with increased stability and low degradation of active components can be prepared by spray drying using maltodextrin and gelatin with the production of microcapsules, which could be exploited as potential food preservatives

Microencapsulation of Cymbopogon citratus D.C. Stapf Essential Oil with Spray Drying: Development, Characterization, and Antioxidant and Antibacterial Activities

This study aimed to microencapsulate Cymbopogon citratus essential oil (CCEO) with spray drying using maltodextrin and gelatin. The effects of the operational conditions (inlet temperature (130&ndash;160 &deg;C), CCEO concentration (5&ndash;15%), maltodextrin concentration (10&ndash;20%)) on the physicochemical stability and antioxidant and antibacterial activities of the CCEO microcapsules were determined. The CCEO microencapsulation process had yield and encapsulation efficiency values varying from 31.02 to 77.53% and 15.86&ndash;61.95%, respectively. CCEO microcapsules had antibacterial effects against Staphylococcus aureus and Escherichia coli with minimum inhibitory concentration varying from 10 to 20%, and total phenolic contents and antioxidant activities varying from 1632 to 4171.08 &mu;g TE/g and 28.55&ndash;45.12 &micro;g/g, respectively. CCEO microcapsules had average diameters varying from 5.10 to 10.11 &micro;m, with spherical external structures without cracks and apparent pores. The best desirable process conditions for CCEO microencapsulation were process inlet temperature of 148 &deg;C, maltodextrin concentration of 15%, and CCEO concentration of 10%. The results showed that CCEO microcapsules with increased stability and low degradation of active components can be prepared by spray drying using maltodextrin and gelatin with the production of microcapsules, which could be exploited as potential food preservatives

The Taking of the Presidential Palace

Chen Yifei and Wei Jingshan; 10 ft. 11 57/64 in. x 15 ft. 3 15/32 in.; oil on canva

Direct antiviral therapy for treatment of hepatitis C: A real-world study from Brazil

Introduction and objectives: Direct antiviral agents (DAAs) including sofosbuvir (SOF), daclatasvir (DCV), simeprevir (SIM) and ombitasvir, paritaprevir and dasabuvir were introduced 2015 in Brazil for treatment of hepatitis C virus (HCV) infection. The aims of this study were to assess effectiveness and safety of HCV treatment with DAA in real-life world in a highly admixed population from Brazil. Materials and methods: All Brazilian reference centers for HCV treatment were invited to take part in a web-based registry, prospectively conducted by the Brazilian Society of Hepatology, to assess outcomes of HCV treatment in Brazil with DAAs. Data to be collected included demographics, disease severity and comorbidities, genotype (GT), viral load, DAA regimens, treatment side effects and sustained virological response (SVR). Results: 3939 patients (60% males, mean age 58 ± 10 years) throughout the country were evaluated. Most had advanced fibrosis or cirrhosis, GT1 and were treated with SOF/DCV or SOF/SIM. Overall SVR rates were higher than 95%. Subjects with decompensated cirrhosis, GT2 and GT3 have lower SVR rates of 85%, 90% and 91%, respectively. Cirrhosis and decompensated cirrhosis in GT1 and male sex and decompensated cirrhosis in GT3 were significantly associated with no SVR. Adverse events (AD) and serious AD occurred in 18% and 5% of those subjects, respectively, but less than 1% of patients required treatment discontinuation. Conclusion: SOF-based DAA regimens are effective and safe in the heterogeneous highly admixed Brazilian population and could remain an option for HCV treatment at least in low-income countries