Biotoxicity assays of quantum dots in in vitro cultures of Medicago sativa and Medicago truncatula

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Biotecnologia

The impact of CdSe/ZnS Quantum Dots in cells of Medicago sativa in suspension culture

Abstract Background: Nanotechnology has the potential to provide agriculture with new tools that may be used in the rapid detection and molecular treatment of diseases and enhancement of plant ability to absorb nutrients, among others. Data on nanoparticle toxicity in plants is largely heterogeneous with a diversity of physicochemical parameters reported, which difficult generalizations. Here a cell biology approach was used to evaluate the impact of Quantum Dots (QDs) nanocrystals on plant cells, including their effect on cell growth, cell viability, oxidative stress and ROS accumulation, besides their cytomobility. Results: A plant cell suspension culture of Medicago sativa was settled for the assessment of the impact of the addition of mercaptopropanoic acid coated CdSe/ZnS QDs. Cell growth was significantly reduced when 100 mM of mercaptopropanoic acid -QDs was added during the exponential growth phase, with less than 50% of the cells viable 72 hours after mercaptopropanoic acid -QDs addition. They were up taken by Medicago sativa cells and accumulated in the cytoplasm and nucleus as revealed by optical thin confocal imaging. As part of the cellular response to internalization, Medicago sativa cells were found to increase the production of Reactive Oxygen Species (ROS) in a dose and time dependent manner. Using the fluorescent dye H2DCFDA it was observable that mercaptopropanoic acid-QDs concentrations between 5-180 nM led to a progressive and linear increase of ROS accumulation. Conclusions: Our results showed that the extent of mercaptopropanoic acid coated CdSe/ZnS QDs cytotoxicity in plant cells is dependent upon a number of factors including QDs properties, dose and the environmental conditions of administration and that, for Medicago sativa cells, a safe range of 1-5 nM should not be exceeded for biological applications.

Multiple sequence alignment correction using constraints

Trabalho apresentado no âmbito do European Master in Computational Logics, como requisito parcial para obtenção do grau de Mestre em Computational Logics

Estimation of infection rate in epidemic models with multiple populations

Dissertação para obtenção do Grau de Mestre em Matemática e Aplicações Especialização em Actuariado, Estatística e Investigação Operacional

Single operation multiple data - paralelismo de dados ao nível da sub-rotina

Dissertação para obtenção do Grau de Mestre em Engenharia Informática

Linear amplification with multiple nonlinear devices

Dissertação para obtenção do Grau de Mestre em Engenharia Electrotécnica e Computadores

Quantum dots: synthesis, functionalization and bioconjugation for biological applications

Dissertation presented to obtain the Ph.D degree in Engineering Sciences and Technology

Desenvolvimento de um ensaio de hibridação múltipla (MHA-MULTIPLE REGION HYBRIDIZATION ASSAY) para identificação presumível de vírus da imunodeficiência humana do tipo 1 (HIV-1) dos subtipos B, G e de formas recombinantes CRF14_BG e CRF02_AG circulantes em Portugal

A maioria dos métodos utilizados na caracterização genética do HIV-1 baseia-se na análise de regiões específicas do genoma viral, fornecendo informação parcial sobre o mesmo e, por consequência, revelando-se inadequados para a identificação de vírus recombinantes. O único método que permite uma caracterização integral do genoma viral passa pela sua sequenciação completa. No entanto, este é um método dispendioso, laborioso e de difícil implementação quando se pretende a análise de elevados números de amostras. Como alternativa a este último, o conjunto de métodos genericamente designados de MHA (Multiple Region Hybridization Assay) baseiam-se na amplificação, por PCR em tempo-real, de várias regiões ao longo do genoma viral e na sua caracterização com sondas específicas (TaqMan). Tendo este modelo por base, o objectivo deste estudo foi o desenvolvimento de um ensaio de hibridação múltipla (MHABG0214) passível de ser aplicado ao estudo de um elevado número de amostras. Este método foi desenvolvido tendo como objectivo a genotipagem as estirpes circulantes dominantes na epidemia Portuguesa, nomeadamente os subtipos B, G e formas genéticas recombinantes CRF02_AG e CRF14_BG. Com base em alinhamentos de sequências de referência de genoma completo, delinearam-se primers universais e subtipo-específicos para a amplificação de diversas regiões codificantes distribuídas ao longo do genoma do HIV-1 (Gag, Protease, Transcriptase Reversa, Integrase, Rev, Gp120 e Gp41). A optimização foi efectuada, inicialmente, para um conjunto de amostras de referência e seguidamente avaliada num conjunto de 50 amostras clínicas. O MHABG0214 foi implementado numa estratégia de PCR em tempo-real, numa detecção dependente de SYBR® Green I para todas as regiões ou, como alternativa, usando sondas TaqMan (Gp41). Apresentamos ainda uma estratégia em que a análise de resultados se baseia, simplesmente, numa abordagem usando PCR/gel de agarose convencional. Estas abordagens constituem ferramentas úteis na identificação das estirpes de HIV-1 em Portugal.

Hole cleaning performance monitoring during the drilling of directional wells

During drilling operation, cuttings are produced downhole and must be removed to avoid issues which can lead to Non Productive Time (NPT). Most of stuck pipe and then Bottom-Hole Assembly (BHA) lost events are hole cleaned related. There are many parameters which help determine hole cleaning conditions, but a proper selection of the key parameters will facilitate monitoring hole cleaning conditions and interventions. The aim of Hole Cleaning Monitoring is to keep track of borehole conditions including hole cleaning efficiency and wellbore stability issues during drilling operations. Adequate hole cleaning is the one of the main concerns in the underbalanced drilling operations especially for directional and horizontal wells. This dissertation addresses some hole cleaning fundamentals which will act as the basis for recommendation practice during drilling operations. Understand how parameters such as Flowrate, Rotation per Minute (RPM), Rate of Penetration (ROP) and Mud Weight are useful to improve the hole cleaning performance and how Equivalent Circulate Density (ECD), Torque & Drag (T&D) and Cuttings Volumes coming from downhole help to indicate how clean and stable the well is. For case study, hole cleaning performance or cuttings volume removal monitoring, will be based on real-time measurements of the cuttings volume removal from downhole at certain time, taking into account Flowrate, RPM, ROP and Drilling fluid or Mud properties, and then will be plotted and compared to the volume being drilled expected. ECD monitoring will dictate hole stability conditions and T&D and Cuttings Volume coming from downhole monitoring will dictate how clean the well is. T&D Modeling Software provide theoretical calculated T&D trends which will be plotted and compared to the real-time measurements. It will use the measured hookloads to perform a back-calculation of friction factors along the wellbore.

Conception and first results of a cross-sectional national study on the demography, disease characteristics and socioeconomics status of the Portuguese patients with multiple sclerosis : the PORT-MS study

RESUMO: Introdução e objetivos: Não existia um estudo multicêntrico que descrevesse as características dos doentes com EM, da doença em si, ou do seu tratamento, em Portugal.Métodos: Doentes McDonald 2010 positivos foram sequencialmente recrutados em 7 centros entre Maio e Novembro 2014. Aplicou-se um Caderno de Recolha de Dados incidindo na demografia, doença, educação e emprego (estudo PORT-MS). Resultados: 561 doentes incluídos. Primeiros sintomas aos 30,2±10,5 anos (RRMS 29,2±10, PPMS 39,4±11,7, p<0,001); diagnóstico 3,2±5,3 anos depois (RRMS 3,0±5,1, PPMS 4,9±2,5, p=0,002); tempo de doença após diagnóstico 9,4±7,2 anos (semelhante RRMS no diagnóstico e PPMS); idade atual 42,9±12,4 anos (grupo RRMS no diagnóstico 42,0±12,1, PPMS 52,5±11,3, p<0,001); EDSS atual 2,5 (RRMS 2.0, PPMS 6.0); proporção feminino:masculino é 2,5:1 (RRMS semelhante, PPMS 1,1:1, p<0,05); no diagnóstico RRMS 90,6%, SPMS 0,9%, PPMS 8,6%; 9,5% dos RRMS encontravam-se em SP na inclusão (nomeadamente os com mais idade no diagnóstico e/ou atualidade ou tempo de doença mais prolongado). PPMS mais frequente em doentes diagnosticados mais tardiamente (p<0,001), onde aumenta também ligeiramente a proporção de mulheres na PPMS. Nas últimas décadas: novos casos mostram estabilidade na proporção de géneros e tipos de doença; idade nos primeiros sintomas e no diagnóstico aumentou ligeiramente, tempo entre eles diminuiu ligeiramente. Proporção sob DMT (Maio 2014): global 84,5%; atualmente RRMS 90,4%; SPMS 70,8%; PPMS 36,8%; progressivas agregadas 48%. Tipo de DMT, amostra global: interferões 56,5%, GA 18,4%, Natalizumab 11,6%, Fingolimod 9,7%. Global: economicamente ativos 61,5%, desemprego 13,5%, 74,1% dos não activos estão reformados por doença. Gravidezes após diagnóstico em 15% mulheres. Casos com história familiar positiva 7,8%. Discussão e conclusões: Incluída cerca de 10% da população portuguesa. Resultados congruentes com dados internacionais. Elevada proporção sob DMT, mesmo EDSS alto e formas progressivas. Terapêuticas de segunda linha sub representadas. Doentes jovens e com doença ligeira com vida económica ativa; restantes essencialmente reformados por doença.---------------- ABSTRACT : Background/aims: In Portugal, there wasn’t a multicentric study on the general characteristics (demography, disease milestones, DMT, socioeconomic status) of Multiple Sclerosis patients. Methods: Patients fulfilling McDonald 2010 criteria were sequentially recruited from May to November 2014 in 7 centers and data was systematically collected. Results: 561 patients included. First symptoms occurred at 30,2±10,5 years-old (RRMS 29,2±10, PPMS 39,4±11,7, p<0,001); diagnosis 3,2±5,3 years later (RRMS 3,0±5,1, PPMS 4,9±2,5, p=0,002); 9,4±7,2 years elapsed since diagnosis (similar for those is RRMS at diagnosis and PPMS); current age 42,9±12,4 years-old (group RRMS at diagnosis 42,0±12,1, PPMS 52,5±11,3, p<0,001); current EDSS 2,5 (RRMS 2.0, PPMS 6.0); females to males 2,5:1 (RRMS similar, PPMS 1,1:1, p<0,05); at diagnosis RRMS 90,6%, SPMS 0,9%, PPMS 8,6%; 9,5% of RRMS reached SP at inclusion (those older at diagnosis, in actuality, or with longer follow-up). PPMS more frequente in patients diagnosed at older ages (p<0,001), also slight increase in females. Along the last decades: new cases have showed stable proportions of gender and disease types; age at first symptoms and diagnosis slightly increased, time between them slightly decreased. Proportion on DMT (May 2014): 84,5% of all; 90,4% of currently in RRMS; 70,8% of SPMS; 36,8% of PPMS; 48% of progressive forms together. Type of DMT, all patients: interferons 56,5%, Glatiramer Acetate 18,4%, Natalizumab 11,6%, Fingolimod 9,7%. Economically active 61,5% of all, unemployment 13,5%, 74,1% of non-active are retired due to disease. Females pregnant after diagnosis 15%. Positive family cases in 7,8%. Discussion/Conclusions: 10% of the national MS population collected. Data generally consistente with international reports. Proportion under DMT relatively high in all disease types, but second line therapies underrepresented. Young patients with mild disease have an active economic life. Those not active are essentially retired due to disease.

Improving the early diagnostic of prostate cancer by multiple biomarker detection with new biosensing devices

Prostate cancer (PCa) is the most common form of cancer in men, in Europe (World Health Organization data). The most recent statistics, in Portuguese territory, confirm this scenario, which states that about 50% of Portuguese men may suffer from prostate cancer and 15% of these will die from this condition. Its early detection is therefore fundamental. This is currently being done by Prostate Specific Antigen (PSA) screening in urine but false positive and negative results are quite often obtained and many patients are sent to unnecessary biopsy procedures. This early detection protocol may be improved, by the development of point-of-care cancer detection devices, not only to PSA but also to other biomarkers recently identified. Thus, the present work aims to screen several biomarkers in cultured human prostate cell lines, serum and urine samples, developing low cost sensors based on new synthetic biomaterials. Biomarkers considered in this study are the following: prostate specific antigen (PSA), annexin A3 (ANXA3), microseminoprotein-beta (MSMB) and sarcosine (SAR). The biomarker recognition may occurs by means of molecularly imprinted polymers (MIP), which are a kind of plastic antibodies, and enzymatic approaches. The growth of a rigid polymer, chemically stable, using the biomarker as a template allows the synthesis of the plastic antibody. MIPs show high sensitivity/selectivity and present much longer stability and much lower price than natural antibodies. This nanostructured material was prepared on a carbon solid. The interaction between the biomarker and the sensing-material produces electrical signals generating quantitative or semi-quantitative data. These devices allow inexpensive and portable detection in point-of-care testing.

Solution processed quantum dot photodetectors

To find sustainable solutions for the production of energy, it is necessary to create photovoltaic technologies that make every photon count. To pursue this necessity, in the present work photodetectors of zinc oxide embedded with nano-structured materials, that significantly raise the conversion of solar energy to electric energy, were developed. The novelty of this work is on the development of processing methodologies in which all steps are in solution: quantum dots synthesis, passivation of their surface and sol-gel deposition. The quantum dot solutions with different capping agents were characterized by UVvisible absorption spectroscopy, spectrofluorimetry, dynamic light scattering and transmission electron microscopy. The obtained quantum dots have dimensions between 2 and 3nm. These particles were suspended in zinc acetate solutions and used to produce doped zinc oxide films with embedded quantum dots, whose electric response was tested. The produced nano-structured zinc oxide materials have a superior performance than the bulk, in terms of the produced photo-current. This indicates that an intermediate band material should have been produced that acts as a photovoltaic medium for solar cells. The results are currently being compiled in a scientific article, that is being prepared for possible submission to Energy and Environmental Science or Nanoscale journals.

Is Modernity Multiple?

Fundação para a Ciência e a Tecnologia (FCT), Fundação Millennium bcp