Produção e avaliação de nanoemulsão catiônica como possível vetor não-viral para pIRES2-EGFP

Gene therapy is based on the transfer of exogenous genetic material into cells or tissues in order to correct, supplement or silencing a particular gene. To achieve this goal, efficient vehicles, viral or non-viral, should be developed. The aim of this work was to produce and evaluate a nanoemulsion system as a possible carrier for no-viral gene therapy able to load a plasmid model (pIRES2-EGFP). The nanoemulsion was produced by the sonication method, after been choose in a pseudo-ternary phase diagram build with 5 % of Captex 355®, 1.2 % of Tween 80®, 0.8 % of Span 80®, 0.16% of stearylamine and water (to 100 %). Measurements of droplet size, polydispersity index (PI), zeta potential, pH and conductivity, were performed to characterize the system. Results showed droplets smaller than 200 nm (PI < 0.2) and zeta potential > 30 mV. The formulation pH was near to 7.0 and conductivity was that expected to oil in water systems (70 to 90 μS/s) A scale up study, the stability of the system and the best sterilization method were also evaluated. We found that the system may be scaled up considering the time of sonication according to the volume produced, filtration was the best sterilization process and nanoemulsions were stable by 180 days at 4 ºC. Once developed, the complexation efficiency of the plasmid (pDNA) by the system was tested by agarose gel electrophoresis retardation assay.. The complexation efficiency increases when stearylamine was incorporated into aqueous phase (from 46 to 115 ng/μL); regarding a contact period (nanoemulsion / pDNA) of at least 2 hours in an ice bath, for complete lipoplex formation. The nanoemulsion showed low toxicity in MRC-5 cells at the usual transfection concentration, 81.49 % of survival was found. So, it can be concluded that a nanoemulsion in which a plasmid model was loaded was achieved. However, further studies concerning transfectation efficiency should be performed to confirm the system as non-viral gene carrier

Paulo Freire e a pedagogia do oprimido: afinidades pós-coloniais

The main objective of the present research is to reflect on the affinities between post-colonial theories - analytical perspectives directed toward the discussion of colonialism and its effects on the contemporary social fabric - and Brazilian educator, Paulo Freire‟s (1921-1997) Pedagogy of the Oppressed, written at the end of the 1960‟s. The study aims to make the argument that the present reflections on the featured work is an example of a post-colonial theoretical framework, delineating a critical modus operandi of colonialism, particularly in its cultural and epistemic dimensions, delineating a problematization of the processes of cognitive domination set, above all, by the European colonization of the Latin American continent, with the formation of the modern-world-system (WALLERSTEIN, 2007), dated from the 16TH Century forward. From this stand point, and especially supported by the contributions of Boaventura de Sousa Santos on the sociology of absence, the present work accentuates Pedagogy of the Oppressed as a set of reflections that bring the possibility of a pedagogy of absence (SANTOS, 1996), having in mind that, this book deals with, the presuppositions of an educational action, which considers the plurality of knowledge and social practices by way of the establishment of a pedagogical practice of collective construction, emancipator and dialogic that arises from the encounter to the indolent reason (SANTOS, 2009) in which the silencing of the voices of the oppressed, construct their conditions of invisibility, promoting also the absence of the social questions inherent to the processes of teaching and learning. It is with this perspective, however, that post colonialism is considered a theoretical site for the affirmation and the reinvention of the Pedagogy of the Oppressed, an obligatory reference in the construction of a prudent knowledge for a decent life (SANTOS, 2006)

O silenciamento no texto jornalístico e a construção social da realidade

This research analyses the silencehood use by the A República journal (Natal/RN), today not being distributed, during the Second World War. Its objective is to unveil the production condition of the news texts, and it was observed that the use of silencehood as a speech strategy with its implications that falls upon the way of behaving and thinking of the society, all that time, influencing the reader in the construction of his image of the reality. During the coverage of the conflict by the local journal it was possible to also observe different speech marks that represented the change in attitude of the Brazilian Government, responsible for the control of what was spread as news. The country lived the dictatorship of the New State and as the war went on the government changed its speech, according to political, social and economical interest s thoughts being played, silencing themes in the name of the national security. We admit as research material journalistic texts that refer to the main facts that occurred during the six years of the world conflict and that is why we used as theoric-metodological support the Speech Analysis

The influence of visual inter-hemispheric connections on spiking, assembly and LFP activities, and their phase relationship during figure-ground stimulation

Desde os descobrimentos pioneiros de Hubel e Wiesel acumulou-se uma vasta literatura descrevendo as respostas neuronais do córtex visual primário (V1) a diferentes estímulos visuais. Estes estímulos consistem principalmente em barras em movimento, pontos ou grades, que são úteis para explorar as respostas dentro do campo receptivo clássico (CRF do inglês classical receptive field) a características básicas dos estímulos visuais como a orientação, direção de movimento, contraste, entre outras. Entretanto, nas últimas duas décadas, tornou-se cada vez mais evidente que a atividade de neurônios em V1 pode ser modulada por estímulos fora do CRF. Desta forma, áreas visuais primárias poderiam estar envolvidas em funções visuais mais complexas como, por exemplo, a separação de um objeto ou figura do seu fundo (segregação figura-fundo) e assume-se que as conexões intrínsecas de longo alcance em V1, assim como as conexões de áreas visuais superiores, estão ativamente envolvidas neste processo. Sua possível função foi inferida a partir da análise das variações das respostas induzidas por um estímulo localizado fora do CRF de neurônios individuais. Mesmo sendo muito provável que estas conexões tenham também um impacto tanto na atividade conjunta de neurônios envolvidos no processamento da figura quanto no potencial de campo, estas questões permanecem pouco estudadas. Visando examinar a modulação do contexto visual nessas atividades, coletamos potenciais de ação e potenciais de campo em paralelo de até 48 eletrodos implantados na área visual primária de gatos anestesiados. Estimulamos com grades compostas e cenas naturais, focando-nos na atividade de neurônios cujo CRF estava situado na figura. Da mesma forma, visando examinar a influência das conexões laterais, o sinal proveniente da área visual isotópica e contralateral foi removido através da desativação reversível por resfriamento. Fizemos isso devido a: i) as conexões laterais intrínsecas não podem ser facilmente manipuladas sem afetar diretamente os sinais que estão sendo medidos, ii) as conexões inter-hemisféricas compartilham as principais características anatômicas com a rede lateral intrínseca e podem ser vistas como uma continuação funcional das mesmas entre os dois hemisférios e iii) o resfriamento desativa as conexões de forma causal e reversível, silenciando temporariamente seu sinal, permitindo conclusões diretas a respeito da sua contribuição. Nossos resultados demonstram que o mecanismo de segmentação figurafundo se reflete nas taxas de disparo de neurônios individuais, assim como na potência do potencial de campo e na relação entre sua fase e os padrões de disparo produzidos pela população. Além disso, as conexões laterais inter-hemisféricas modulam estas variáveis dependendo da estimulação feita fora do CRF. Observamos também uma influência deste circuito lateral na coerência entre potenciais de campo entre eletrodos distantes. Em conclusão, nossos resultados dão suporte à ideia de um mecanismo complexo de segmentação figura-fundo atuando desde as áreas visuais primárias em diferentes escalas de frequência. Esse mecanismo parece envolver grupos de neurônios ativos sincronicamente e dependentes da fase do potencial de campo. Nossos resultados também são compatíveis com a hipótese que conexões laterais de longo alcance também fazem parte deste mecanismo