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Ribeiro R.S.R.,University of Porto | Soppera O.,CNRS Mulhouse Institute of Materials Science | Oliva A.G.,New University of Lisbon | Guerreiro A.,University of Porto | Jorge P.A.S.,Institute Engineering Of Sistemas E Computadores Tecnologia E Ciencia
Journal of Lightwave Technology | Year: 2015

In the last few decades, optical trapping has played an unique role concerning contactless trapping and manipulation of biological specimens. More recently, optical fiber tweezers (OFTs) are emerging as a desirable alternative to bulk optical systems. In this paper, an overview of the state of the art of OFTs is presented, focusing on the main fabrication methods, their features and main achievements. In addition, new OFTs fabricated by guided wave photo polymerization are reported. Their theoretical and experimental characterization is given and results demonstrating its application in the manipulation of yeast cells and the organelles of plant cells are presented. © 1983-2012 IEEE.


Poinhos R.,University of Porto | Oliveira B.M.P.M.,University of Porto | Oliveira B.M.P.M.,Institute Engineering Of Sistemas E Computadores Tecnologia E Ciencia | Correia F.,University of Porto | Correia F.,Centro Hospitalar Of Sao Joao
Revista de Alimentacao Humana | Year: 2013

Self-efficacy refers to the beliefs in the ability to organise and implement the action plans needed to achieve a certain result and the feeling of control over the behaviours and environment. It determines the initiation, maintenance and cessation of strategies or behaviours, being a good predictor of eating behaviour. Despite its potential in terms of research, prognosis and evaluation of interventions, we are unaware of instruments to assess global features of food self-efficacy validated for the Portuguese population. The aim of this work is to develop and validate a scale to assess general features of food self-efficacy ("Escala de Auto-Eficácia Alimentar Global"). We evaluated a sample of 276 higher education students, and the analysis was performed separately for the subsamples of females and males. The items were created through the adaptation of the six items of the self-efficacy subscale of the "Inventário Clínico de Auto-Conceito" (Serra, 1986). The analysis led to the maintenance of five of the six items initially considered. The scale shows an unifactorial structure, and the proportion of total variance explained by the principal components extracted is higher than 64%. It also shows good internal consistency, with values of Cronbach's alpha above 0.85. The study of relations with other measures showed evidence of its convergent and discriminant validities. The "Escala de Auto-Eficácia Alimentar Global" may prove to be an useful tool for the prognosis and the evaluation of interventions related to the change in eating habits.


Poinhos R.,University of Porto | Oliveira B.M.P.M.,University of Porto | Oliveira B.M.P.M.,Institute Engineering Of Sistemas E Computadores Tecnologia E Ciencia | Correia F.,University of Porto | Correia F.,Centro Hospitalar Of Sao Joao
Nutrition | Year: 2015

Objectives: The aim of this study was to relate social desirability with eating behavior dimensions among higher education students in Portugal, and to assess the effect of social desirability on the association between pairs of eating behavior dimensions. Methods: Data from 266 higher education students (62.8% women) aged between 18 and 27y were evaluated. Social desirability and several eating behavior dimensions (emotional and external eating, flexible and rigid restraint, binge eating, and eating self-efficacy) were assessed. Results: In both women and men, social desirability showed negative associations with emotional, external, and binge eating, and positive associations with eating self-efficacy. For the majority of the correlations, the control for social desirability led to a decrease in the strength of the association: Social desirability showed a greater effect on the associations between external and binge eating, external eating and eating self-efficacy, binge eating and eating self-efficacy, and emotional and external eating. Conclusion: This study demonstrated that social desirability should be considered when assessing the dimensions of eating behavior, namely eating self-efficacy and dimensions related to overeating. © 2015 Elsevier Inc.


Moayyed H.,Institute Engineering Of Sistemas E Computadores Tecnologia E Ciencia | Moayyed H.,University of Porto | Leite I.T.,Institute Engineering Of Sistemas E Computadores Tecnologia E Ciencia | Leite I.T.,University of Porto | And 6 more authors.
IEEE Sensors Journal | Year: 2014

An effective analytical model combining geometrical optics with the transfer-matrix theory for stratified optical media is applied to investigate the sensing properties of tapered optical fiber surface plasmon resonance (SPR) sensors incorporating Ag-Au bimetallic layers, particularly in the context of phase interrogation. The performance of the sensing structures is studied as a function of the tapering parameters and thickness of the metallic layers. It is shown that the Ag-Au bimetallic combination is capable of improving the resolution and tuning working region of SPR fiber-optic sensors and that by tapering the sensing structures enhanced sensitivity can be achieved when phase interrogation is considered. © 2012 IEEE.


Poinhos R.,University of Porto | Rowcliffe P.,Aramark Ltd | Viana V.,University of Porto | Viana V.,Centro Hospitalar Of Sao Joao | And 3 more authors.
Revista de Alimentacao Humana | Year: 2013

Our aim was to adapt for Portuguese and validate the flexible and rigid control subscales of eating behaviour proposed by Westenhoefer et al. (1999) and to analyse their relationship with socio-demographic and anthropometric variables. One sample from the general population (n = 231) and another composed by higher education students (n = 257) were evaluated. The adaptation of the subscales involved their translation, back translation and cultural adaptation. The subscales' final version showed unifactorial structure and acceptable internal consistency in both samples (Cronbach's alpha between 0,750 and 0,817). Higher scores in each subscale correspond to higher dietary restraint. Women had higher levels of both types of control. For men age was positively associated with flexible control, and for women education was positively associated with both types of restraint. In the students' sample, rigid control significantly predicted BMI (positive association). The present study supplies an instrument to assess flexible and rigid control of eating behaviour adapted to the Portuguese population.

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