51 resultados para UV detection


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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.

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Do presente trabalho resultou a submissão de um artigo, com o título UV Curing Adhesives for Conservation of Glass- Chemical and Mechanical Stability, para comunicação oral em conferência internacional intitulada Recent Advances in Glass and Ceramics Conservation, a ocorrer em Wroclaw, Polónia, de 25 a 29 de Maio de 2016, no âmbito do ICOM-CC Glass and Ceramics Working Group Interim Meeting.

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The EM3E Master is an Education Programme supported by the European Commission, the European Membrane Society (EMS), the European Membrane House (EMH), and a large international network of industrial companies, research centres and universities (http://www.em3e.eu)

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In this work two different procedures to utilize the sol-gel technology were applied to immobilize/encapsulate enzymes and living cells. CO2 has reached levels in the atmosphere that make it a pollutant. New methods to utilize this gas to obtain products of added value can be very important, both from an environmentally point of view and from an economic standpoint. The first goal of this work was to study the first reaction of a sequential, three-step, enzymatic process that carries out the conversion of CO2 to methanol. Of the three oxidoreductases involved, our focus was on formate dehydrogenase (FateDH) that converts CO2 to formate. This reaction requires the presence of the cofactor β-nicotinamide adenine dinucleotide in reduced form (NADH). The cofactor is expensive and unstable. Our experiments were directed towards generating NADH from its oxidized form (NAD+), using glutamate dehydrogenase (GDH). The formation of NADH from NAD+ in aqueous medium was studied with both free and sol-gel entrapped GDH. This reaction was then followed by the conversion of CO2 to formate, catalysed by free or sol-gel entrapped FateDH. The quantification of NADH/NAD+ was made using UV/Vis spectroscopy. Our results showed that it was possible to couple the GDH-catalyzed generation of the cofactor NADH with the FateDH-catalyzed conversion of CO2, as confirmed by the detection of formate in the medium, using High Performance Liquid Chromatography (HPLC). The immobilization of living cells can be advantageous from the standpoint of ease of recovery, reutilization and physical separation from the medium. Also dead cells may not always exhibit enzymatic activities found with living cells. In this work cell encapsulation was performed using Escherichia coli bacteria. To reduce toxicity for living organisms, the sol-gel method was different than for enzymes, and involved the use of aqueous-based precursors. Initial encapsulation experiments and viability tests were carried out with E. coli K12. Our results showed that sol-gel entrapment of the cells was achieved, and that cell viability could be increased with additives, namely betaine that led to greater viability improvement and was selected for further studies. For an approach to “in-cell” Nuclear Magnetic Resonance (NMR) experiments, the expression of the protein ctCBM11 was performed in E. coli BL21. It was possible to obtain an NMR signal from the entrapped cells, a considerable proportion of which remained alive after the NMR experiments. However, it was not possible to obtain a distinctive NMR signal from the target protein to distinguish it from the other proteins in the cell.

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Conventional molecular techniques for detection and characterization of relevant nucleic acid (i.e. DNA) sequences are, nowadays, cumbersome, expensive and with reduced portability. The main objective of this dissertation consisted in the optimization and validation of a fast and low-cost colorimetric nanodiagnostic methodology for the detection of single nucleotide polymorphisms (SNPs). This was done considering SNPs associated to obesity of commercial interest for STAB VIDA, and subsequent evaluation of other clinically relevant targets. Also, integration of this methodology into a microfluidic platform envisaging portability and application on points-of-care (POC) was achieved. To warrant success in pursuing these objectives, the experimental work was divided in four sections: i) genetic association of SNPs to obesity in the Portuguese population; ii) optimization and validation of the non-cross-linking approach for complete genotype characterization of these SNPs; iii) incorporation into a microfluidic platform; and iv) translation to other relevant commercial targets. FTO dbSNP rs#:9939609 carriers had higher body mass index (BMI), total body fat mass, waist perimeter and 2.5 times higher risk to obesity. AuNPs functionalized with thiolated oligonucleotides (Au-nanoprobes) were used via the non-cross-linking to validate a diagnostics approach against the gold standard technique - Sanger Sequencing - with high levels of sensitivity (87.50%) and specificity (91.67%). A proof-of-concept POC microfluidic device was assembled towards incorporation of the molecular detection strategy. In conclusion a successful framework was developed and validated for the detection of SNPs with commercial interest for STAB VIDA, towards future translation into a POC device.

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RESUMO - Em 1994/1995 o modelo legal de organização de serviços de Medicina do Trabalho instituído na década de 1960 foi substituído por uma nova superestrutura de serviços de Segurança, Higiene e Saúde dos Trabalhadores (SHST) nos locais de trabalho. O presente estudo pretende descrever e analisar em que medida o novo enquadramento jurídico de SHST, iniciado em 1994/1995 e correspondente genericamente à fase da Nova Saúde Ocupacional, foi acompanhado de alterações: (1) na percepção do grau de satisfação dos médicos do trabalho quanto ao seu papel e estatuto profissionais e (2) nas repercussões na sua prática profissional. O presente estudo (empírico, descritivo e comparativo) abrangeu um grupo de médicos do trabalho diplomados pela Escola Nacional de Saúde Pública (n = 153), de quem se recolheu, através de um questionário aplicado em 1993 e 2000, a opinião sobre as mudanças organizacionais da SHST. O papel e funções dos médicos do trabalho e as garantias de exercício profissional não se alteraram de forma importante, tendo a prática profissional da medicina do trabalho na modalidade «medicina do trabalho de empresa» (serviços internos e externos) diminuído, apesar de continuar a ser a forma de exercício predominante dos médicos do trabalho. O tempo dedicado à sua actividade situou-se num valor médio próximo das 20 horas semanais, sem alterações importantes entre 1993 e 2000. Concluiu-se que, no essencial, a publicação da nova legislação sobre organização de cuidados de MT/SHST/SO em 1994 e 1995 não reforçou significativamente as condições gerais de exercício da medicina do trabalho.