Biosynthesis, detection and toxicology of ochratoxins - optimisation of production

Ochratoxin A (OTA) is a very well known mycotoxin found in several food commodities for which maximum limits are being discussed in EC in other to produce appropriate regulations. OTA is one of several ochratoxins produced by Aspergillus and Penicillium species. All the compounds in this group have a molecular structure very similar to OTA and some were already isolated from natural substrates. Several of these compounds such as ochratoxin , methyl and ethyl ester of ochratoxin A, 4-R and S-hydroxyochratoxin A, 10-hydroxyochratoxin A and ochratoxin A open lactone are commercially unavailable. However, they can be easily synthesized through OTA modification. With the main objective of its application on further research works, OTA production, isolation and purification has been optimised from an A. alliaceus strain grown on wheat medium. Synthesis and purification of some OTA derivatives has been achieved and an HPLC method for their detection was optimised. Data about their production by several species of Aspergillus will be presented. The toxicological properties of ochratoxins are still not very clear and a future EC safety limit for OTA will depend on e.g., a better clarification of its carcinogenity. Could OTA derivatives play a role here?

The potential field method and the nonlinear attractor dynamics approach: what are the differences?

One of the most popular approaches to path planning and control is the potential field method. This method is particularly attractive because it is suitable for on-line feedback control. In this approach the gradient of a potential field is used to generate the robot's trajectory. Thus, the path is generated by the transient solutions of a dynamical system. On the other hand, in the nonlinear attractor dynamic approach the path is generated by a sequence of attractor solutions. This way the transient solutions of the potential field method are replaced by a sequence of attractor solutions (i.e., asymptotically stable states) of a dynamical system. We discuss at a theoretical level some of the main differences of these two approaches.

Descrição e reflexão sobre um percurso profissional

Relatório de atividade profissional de mestrado em Ensino da Música

Thermal conditions affecting heat transfer in FDM/FFE: a contribution towards the numerical modelling of the process

The performance of parts produced by Free Form Extrusion (FFE), an increasingly popular additive manufacturing technique, depends mainly on their dimensional accuracy, surface quality and mechanical performance. These attributes are strongly influenced by the evolution of the filament temperature and deformation during deposition and solidification. Consequently, the availability of adequate process modelling software would offer a powerful tool to support efficient process set-up and optimisation. This work examines the contribution to the overall heat transfer of various thermal phenomena developing during the manufacturing sequence, including convection and radiation with the environment, conduction with support and between adjacent filaments, radiation between adjacent filaments and convection with entrapped air. The magnitude of the mechanical deformation is also studied. Once this exercise is completed, it is possible to select the material properties, process variables and thermal phenomena that should be taken in for effective numerical modelling of FFE.

Tunnel engineering – influence of the type and the quantity of measurements in the back analysis of geomechanical parameters

The monitoring data collected during tunnel excavation can be used in inverse analysis procedures in order to identify more realistic geomechanical parameters that can increase the knowledge about the interested formations. These more realistic parameters can be used in real time to adapt the project to the real structure in situ behaviour. However, monitoring plans are normally designed for safety assessment and not especially for the purpose of inverse analysis. In fact, there is a lack of knowledge about what types and quantity of measurements are needed to succeed in identifying the parameters of interest. Also, the optimisation algorithm chosen for the identification procedure may be important for this matter. In this work, this problem is addressed using a theoretical case with which a thorough parametric study was carried out using two optimisation algorithms based on different calculation paradigms, namely a conventional gradient-based algorithm and an evolution strategy algorithm. Calculations were carried for different sets of parameters to identify several combinations of types and amount of monitoring data. The results clearly show the high importance of the available monitoring data and the chosen algorithm for the success rate of the inverse analysis process.

Entre Tapas e Beijos: estudo sobre a violência doméstica contra a mulher no Estado da Paraíba (Brasil), após a entrada em vigor da Lei Maria da Penha (Lei nº 11.340/2006)

Dissertação de mestrado em Direitos Humanos

Attachment orientation and caretaking memories in fathers during the transition to parenthood

Dissertação de mestrado em Psicologia Aplicada

Mothers' beliefs concerning severity and need for intervention in child maltreatment

Dissertação de mestrado integrado em Psicologia Clínica e da Saúde

O ajustamento psicossocial de jovens com consumos de substâncias psicoativas em escolas profissionais do grande Porto

Tese de Doutoramento em Estudos da Criança (Área de Especialidade Psicologia do Desenvolvimento e Educação)

The role of IFNγ in higher brain function: in health and under chronic stress

Tese de Doutoramento em Ciências da Saúde

Quando a luta pelos direitos sexuais se faz no feminino: um estudo de caso sobre o associativismo lésbico em Portugal

Dissertação de mestrado em Sociologia (área de especialização em Desenvolvimento e Políticas Sociais)

FISHji: new ImageJ macros for the quantification of fluorescence in epifluorescence images

Fluorescence in situ hybridization (FISH) is based on the use of fluorescent staining dyes, however, the signal intensity of the images obtained by microscopy is seldom quantified with accuracy by the researcher. The development of innovative digital image processing programs and tools has been trying to overcome this problem, however, the determination of fluorescent intensity in microscopy images still has issues due to the lack of precision in the results and the complexity of existing software. This work presents FISHji, a set of new ImageJ methods for automated quantification of fluorescence in images obtained by epifluorescence microscopy. To validate the methods, results obtained by FISHji were compared with results obtained by flow cytometry. The mean correlation between FISHji and flow cytometry was high and significant, showing that the imaging methods are able to accurately assess the signal intensity of fluorescence images. FISHji are available for non-commercial use at http://paginas.fe.up.pt/nazevedo/.

A relação entre família e escola e a perspectiva de minimização das dificuldades comportamentais e cognitivas apresentadas por adolescentes com Síndrome do Alcoolismo Fetal (SAF): estudos de casos na cidade de Manaus

Dissertação de mestrado em Educação Especial (área de especialização em Dificuldades de Aprendizagem Específicas)

Utentes da Consulta Externa de Ginecologia/Obstetrícia da Maternidade Júlio Dinis

Com o objectivo de fazer a caracterização da situação social e demográfica e das condições de saúde médica e psicológica das utentes da Consulta Externa de Ginecologia/Obstretícia da Maternidade Júlio Dinis e de seus companheiros, duzentas mulheres e cento e setenta e cinco homens (N=375) foram entrevistados com base num questionário desenhado para o efeito, durante o primeiro trimestre de gestação. Observamos o desfavorecimento social e económico da amostra, particularmente no grupo das mulheres. Constatamos que a situação matrimonial e familiar é estável; no entanto, muitos agregados familiares são recentes, incluem outros familiares e este é um primeiro filho do casal. A rede de apoio social e emocional da amostra é geralmente constituída por familiares, estando mais presente para as mulheres do que para os homens e muitas vezes o companheiro não é referido como confidente, sobretudo pelas mulheres. A gestação não é geralmente de risco; não obstante, a presença frequente de problemas psicológicos uma pior aceitação inicial da gravidez no caso das mulheres. Os hábitos de vida tornam-se mais saudáveis com a gestação; no entanto, é ainda elevado o consumo de substâncias, como o tabaco, pela grávida. Problemas ginecológicos e obstétricos foram referidos, assim como a presença de adversidades na história psicológica e desenvolvimental dos participantes. Concluímos que as utentes da Consulta Externa de Ginecologia/Obstetrícia da Maternidade Júlio Dinis e seus companheiros apresentam indicadores relevantes de risco médico, psicológico e social que devem ser considerados na prestação de melhores cuidados de saúde.