T cell Maturation and Regulatory T Cell Differentiation:From the Thymus to the Periphery

Immunological tolerance, that is, the failure to mount an immune response to an otherwise immunogenic molecule, is one of the fundamental questions in immunology. The fact that lymphocytes express antigen receptors that are generated randomly and have the potential to recognize any conceivable antigen, adds another puzzle to the physiology of immunological tolerance. The other side of the coin, the general absence of immune responses to self antigens, is ensured by a tight regulation and several selection steps during T and B cell differentiation. One of these processes is the differentiation of regulatory T cells (Treg). While developing in the thymus, T cell clones bearing receptors with high affinity/avidity to antigens present at the time of differentiation may be eliminated by apoptosis or, alternatively, express Foxp3 and become Treg. Treg are key players in the regulation of immunological tolerance since humans and mice with complete loss of function variants of this gene develop fatal autoimmune conditions early in life.(...)

Modelação numérica da agitação marítima: o caso do terminal XXI do Porto de Sines

Dissertação para obtenção do Grau de Mestre em Engenharia Civil

Migration and differentiation of neuronal precursors in the postnatal brain: insights from the subventricular zone and cerebellum

Fundação para a Ciência e a Tecnologia - SFRH/BD/42848/2008, através do Programa MIT_Portugal em Sistemas de Bioengenharia; projectos PTDC/SAUNEU/104415/2008 e Projecto ref. 96542 da Fundação Caloust Gulbenkian

Genetic diversity and differentiation in natural Plasmodium falciparum populations inferred by molecular typing of the merozoite surface proteins 1 and 2

Genetic diversity and differentiation, inferred by typing the polymorphic genes coding for the merozoite surface proteins 1 (Msp-1) and 2 (Msp-2), were compared for 345 isolates belonging to seven Plasmodium falciparum populations from three continents. Both loci yielded similar estimates of genetic diversity for each population, but rather different patterns of between-population differentiation, suggesting that natural selection on these loci, rather than the transmission dynamics of P. falciparum, determines the variation in allele frequencies among populations.

The Role of the Endoplasmic Reticulum Stress Transducer Ire1 during Photoreceptor Differentiation in Drosophila

Dissertation presented to obtain the Ph.D degree in Biology.

Role of Notch signaling on the differentiation of early lymphoid progenitors cells: a view throughout the development of the embryonic chicken thymus and spleen

Dissertação para a obtenção do grau de Mestre em Genética Molecular e Biomedicina

Avaliação económica de um projecto de investimento num sistema de retorno de gases num Terminal Portuário

Dissertação para obtenção do grau de Mestre em Engenharia e Gestão Industrial

Differentiation of Candida species obtained from nosocomial candidemia using RAPD-PCR technique

Thirteen strains of the genus Candida were isolated from catheter, urine and surgical wounds from individual patients of the Santa Casa de Misericórdia, Belo Horizonte, MG, Brazil. Ten strains were characterized as Candida albicans, two as Candida glabrata, and one as Candida parapsilosis. Isolates were evaluated for molecular relatedness by random amplified polymorphic DNA technique using 15 primers. The analysis of the genomic DNA obtained revealed a low intraspecific polymorphism and did not allow for the differentiation between strains of the same species obtained from distinct clinical sources (catheter, urine and surgical wounds). The RAPD profiles generated were able to differentiate among the species of Candida albicans, Candida parapsilosis and Candida glabrata strains isolated in this study.

Spore differentiation in relation to the infectious cycle of the enteric pathogen Clostridium difficile

Clostridium difficile is a gram positive, spore former, anaerobic bacterium that is able to cause infection and disease, with symptoms ranging from mild diarrhea to pseudomembranous colitis, toxic megacolon, sepsis and death. In the last decade new strains have emerged that caused outbreaks of increased disease severity and higher recurrence, morbidity and mortality rates, and C. difficile is now considered both a main nosocomial pathogen associated with antibiotic therapy as well as a major concern in the community.(...)

Identification and differentiation of Candida species from pediatric patients by random amplified polymorphic DNA

Thirty-four Candida isolates were analyzed by random amplified polymorphic DNA using the primer OPG-10:24 Candida albicans; 4 Candida tropicalis; 2 Candida parapsilosis; 2 Candida dubliniensis; 1 Candida glabrata and 1 Candida krusei. The UPGMA-Pearson correlation coefficient was used to calculate the genetic distance between the different Candida groupings. Samples were classified as identical (correlation of 100%); highly related samples (90%); moderately related samples (80%) and unrelated samples (< 70%). The results showed that the RAPD proposed was capable of classifying the isolates coherently (such that same species were in the same dendrogram), except for two isolates of Candida parapsilosis and the positive control (Netherlands, 1973), probably because they are now recognized as three different species. Concerning the only fluconazole-resistant Candida tropicalis isolate with a genotype that was different to the others, the data were insufficient to affirm that the only difference was the sensitivity to fluconazole. We concluded that the Random Amplified Polymorphic DNA proposed might be used to confirm Candida species identified by microbiological methods.

Optimização energética no terminal portuário do complexo petroquímico de Sines

Actualmente a indústria petroquímica é cada vez mais confrontada com a necessidade de poupança de custos. O presente trabalho surge dessa mesma necessidade e foi desenvolvido, no âmbito de um estágio curricular, no Complexo Petroquímico da Repsol, em Sines, durante um período de seis meses. O principal objectivo do estágio foi a optimização energética dos períodos diários de envio de etileno, dentro do complexo, bem como a avaliação energética dos sistemas de refrigeração, no terminal portuário, tendo-se utilizado o software Aspen HYSYS como simulador dos processos. Essa avaliação energética consistiu no cálculo dos coeficientes de performance e das eficiências dos vários compressores, tendo-se verificado que ambos os parâmetros encontram-se abaixo das condições de design para todos os processos, com a excepção do coeficiente de performance do sistema de refrigeração do 1,3-butadieno. Foram desenvolvidas ferramentas em excel que permitem a avaliação em tempo real da eficiência dos vários sistemas de refrigeração, que pode ser usada na sua optimização, ajustando as eficiências reais às de design. Foram estudados dois projectos a implementar no terminal portuário: um sobre a implementação de variadores de frequência nas liquefacções de etileno, que permitirá uma poupança de 62 kW-h/t de etileno recebida, e outro projecto sobre a instalação de um permutador refrigerado com água salgada, que seria colocado a jusante dos aero-arrefecedores, nas liquefacções. Este estudo permitiu concluir que no caso em que o aero-arrefecedor está desligado, poupar-se-ia em média 2,95 kW-h/t de etileno, e quando o aero-arrefecedor estiver em série com o permutador, poupar-se-ia em média 1,88 kW-h/t de etileno. No âmbito da avaliação energética, foram estimadas também as perdas energéticas nos vários compressores do terminal portuário, tendo-se constatado que os compressores do sistema de refrigeração do 1,3-butadieno apresentam maiores perdas por tonelada de produto recebido. No caso da optimização energética, verificou-se que os casos mais rentáveis eram o 3, 4 e o de estudo, sendo que estes permitiram poupanças na ordem dos 900000 €. Concluiu-se também que liquefazer no terminal é melhor das Segundas às Sextas, a partir de 2 t/h, enquanto que aos Sábado, é a partir de 3 t/h. Aos Domingos liquefazer no terminal compensa sempre, porque não há horas de ponta nem horas cheias.

Amiloidose e insuficiência renal crônica terminal associada à hanseníase

O envolvimento renal na hanseníase é diverso, incluindo glomerulonefrites, amiloidose e nefrite túbulo-intersticial. Um homem de 58 anos foi admitido com edema de membros inferiores e dispnéia. Na admissão, havia retenção de escórias nitrogenadas, anemia, hipercalemia e acidose metabólica, com necessidade de hemodiálise. Referia história de hanseníase virchoviana. Foi realizada biopsia renal, compatível com amiloidose. O paciente evoluiu estável, sem recuperação da função renal, permanecendo em tratamento hemodialítico. A hanseníase deve ser investigada em todo paciente com perda de função renal, sobretudo naqueles que apresentam lesões cutâneas ou outras manifestações sugestivas de hanseníase.

Differentiation between Candida albicans and Candida dubliniensis using hypertonic Sabouraud broth and tobacco agar

INTRODUCTION: Opportunistic fungal infections in immunocompromised hosts are caused by Candida species, and the majority of such infections are due to Candida albicans. However, the emerging pathogen Candida dubliniensis demonstrates several phenotypic characteristics in common with C. albicans, such as production of germ tubes and chlamydospores, calling attention to the development of stable resistance to fluconazole in vitro. The aim of this study was to evaluate the performance of biochemistry identification in the differentiating between C. albicans and C. dubliniensis, by phenotyping of yeast identified as C. albicans. METHODS: Seventy-nine isolates identified as C. albicans by the API system ID 32C were grown on Sabouraud dextrose agar at 30°C for 24-48h and then inoculated on hypertonic Sabouraud broth and tobacco agar. RESULTS: Our results showed that 17 (21.5%) isolates were growth-inhibited on hypertonic Sabouraud broth, a phenotypic trait inconsistent with C. albicans in this medium. However, the results observed on tobacco agar showed that only 9 (11.4%) of the growth-inhibited isolates produced characteristic colonies of C. dubliniensis (rough colonies, yellowish-brown with abundant fragments of hyphae and chlamydospores). CONCLUSIONS: The results suggest that this method is a simple tool for screening C. albicans and non-albicans yeast and for verification of automated identification.

Is there space to build one more transshipment terminal within Portuguese territory?

NSBE - UNL

Rapid detection and differentiation of mycobacterial species using a multiplex PCR system

Introduction The early diagnosis of mycobacterial infections is a critical step for initiating treatment and curing the patient. Molecular analytical methods have led to considerable improvements in the speed and accuracy of mycobacteria detection. Methods The purpose of this study was to evaluate a multiplex polymerase chain reaction system using mycobacterial strains as an auxiliary tool in the differential diagnosis of tuberculosis and diseases caused by nontuberculous mycobacteria (NTM) Results Forty mycobacterial strains isolated from pulmonary and extrapulmonary origin specimens from 37 patients diagnosed with tuberculosis were processed. Using phenotypic and biochemical characteristics of the 40 mycobacteria isolated in LJ medium, 57.5% (n=23) were characterized as the Mycobacterium tuberculosis complex (MTBC) and 20% (n=8) as nontuberculous mycobacteria (NTM), with 22.5% (n=9) of the results being inconclusive. When the results of the phenotypic and biochemical tests in 30 strains of mycobacteria were compared with the results of the multiplex PCR, there was 100% concordance in the identification of the MTBC and NTM species, respectively. A total of 32.5% (n=13) of the samples in multiplex PCR exhibited a molecular pattern consistent with NTM, thus disagreeing with the final diagnosis from the attending physician. Conclusions Multiplex PCR can be used as a differential method for determining TB infections caused by NTM a valuable tool in reducing the time necessary to make clinical diagnoses and begin treatment. It is also useful for identifying species that were previously not identifiable using conventional biochemical and phenotypic techniques.