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Publicações

Publicações por CAP

2021

Consumer Knowledge about Food Labeling and Fraud

Autores
Moreira, MJ; Garcia Diez, J; de Almeida, JMMM; Saraiva, C;

Publicação
FOODS

Abstract
Food fraud is a growing problem and happens in many ways including mislabelling. Since lack of consumers' knowledge about mandatory food labeling information and different types of food fraud may impact public health, the present work assesses consumers' knowledge about these issues. Principal component analysis was performed to obtain a smaller number of uncorrelated factors regarding the usefulness and confidence of information displayed in food labels and the perception of food fraud. Results indicated that information displayed in food labels is useful, however the way it is presented may decrease consumer interest and understanding. Regarding respondents' confidence in foodstuffs, over half of them stated that information provided in food labels is reliable. However, a lack of confidence about food composition is observed in those processed foodstuffs such as meat products. Food fraud is recognized by more than half of respondents with a higher perception of those practices that imply a risk to public health than those related to economic motivation. Age and education of consumers influenced the perception of the information displayed in the food labels, their confidence and knowledge about food fraud. Implementation of education programs to increase consumer knowledge about food labelling and fraud is essential. Respondents' perception results could be use as guidelines by the food industry to improve food label design in order to enhance consumer understanding.

2021

Multiparameter Sensor Based on a Multi-Interferometric Serial Configuration for Temperature and Strain Measurements

Autores
Perez-Herrera R.A.; Bravo M.; Leandro D.; Novais S.; Pradas J.; Lopez-Amo M.;

Publicação
IEEE Journal of Selected Topics in Quantum Electronics

Abstract
In this work, a multi-parameter point sensor based on the combination of Fabry-Perot (FP) and the anti-resonant (AR) reflecting guidance in cascade configuration is proposed and experimentally demonstrated. This structure, based on FP interference and AR reflecting guidance, was fabricated with two different air micro-cavities. The attained experimental results showed different strain and temperature sensitivities for the antiresonance contribution. However, when analyzing the FP interference, only strain sensitivity was observed, demonstrating that this air micro-cavity was also insensitive to temperature variations.

2020

iLoF: An intelligent Lab on Fiber Approach for Human Cancer Single-Cell Type Identification

Autores
Paiva, JS; Jorge, PAS; Ribeiro, RSR; Balmana, M; Campos, D; Mereiter, S; Jin, CS; Karlsson, NG; Sampaio, P; Reis, CA; Cunha, JPS;

Publicação
SCIENTIFIC REPORTS

Abstract
With the advent of personalized medicine, there is a movement to develop "smaller" and "smarter" microdevices that are able to distinguish similar cancer subtypes. Tumor cells display major differences when compared to their natural counterparts, due to alterations in fundamental cellular processes such as glycosylation. Glycans are involved in tumor cell biology and they have been considered to be suitable cancer biomarkers. Thus, more selective cancer screening assays can be developed through the detection of specific altered glycans on the surface of circulating cancer cells. Currently, this is only possible through time-consuming assays. In this work, we propose the "intelligent" Lab on Fiber (iLoF) device, that has a high-resolution, and which is a fast and portable method for tumor single-cell type identification and isolation. We apply an Artificial Intelligence approach to the back-scattered signal arising from a trapped cell by a micro-lensed optical fiber. As a proof of concept, we show that iLoF is able to discriminate two human cancer cell models sharing the same genetic background but displaying a different surface glycosylation profile with an accuracy above 90% and a speed rate of 2.3 seconds. We envision the incorporation of the iLoF in an easy-to-operate microchip for cancer identification, which would allow further biological characterization of the captured circulating live cells.

2020

Femtosecond laser direct written off-axis fiber Bragg gratings for sensing applications

Autores
Viveiros, D; Amorim, VA; Maia, JM; Silva, S; Frazao, O; Jorge, PAS; Fernandes, LA; Marques, PVS;

Publicação
OPTICS AND LASER TECHNOLOGY

Abstract
First order off-axis fiber Bragg gratings (FBGs) were fabricated in a standard single mode fiber (SMF-28e) through femtosecond laser direct writing. A minimum offset distance between the grating and core center of 2.5 mu m was found to create a multimode section, which supports two separate fiber modes (LP0,1 and LP1,1), each split into two degenerate polarization modes. The resulting structure breaks the cylindrical symmetry of the fiber, introducing birefringence (approximate to 10(-4)) resulting in a polarization dependent Bragg wavelength for each mode. Based on the modal and birefringence behavior, three off-axis FBGs were fabricated with 3.0, 4.5 and 6.0 mu m offsets from the core center, and then characterized in strain, temperature, and curvature. The tested off-axis FBGs exhibited a similar strain sensitivity of similar to 1.14 pm/mu epsilon and a temperature sensitivity of similar to 12 pm/C. The curvature and orientation angle were simultaneously monitored by analyzing the intensity fluctuation and the wavelength shift of the LP1,1 Bragg resonance. A maximum curvature sensitivity of 0.53 dB/m(-1) was obtained for the off-axis FBG with a 3.0 mu m offset.

2020

Femtosecond laser micromachining of Fabry-Perot interferometers in SMF-28 fiber for pressure sensing (Conference Presentation)

Autores
Viveiros, D; Almeida, JMd; Coelho, L; Maia, JM; Amorim, VA; Vasconcelos, H; Jorge, PAS; Marques, PVS;

Publicação
Optical Sensing and Detection VI

Abstract

2020

Femtosecond Laser-written Long Period Fibre Gratings coated with Titanium Dioxide for improved sensitivity

Autores
Viveiros, D; de Almeida, JMMM; Coelho, L; Vasconcelos, H; Amorim, VA; Maia, JM; Jorge, PAS; Marques, PVS;

Publicação
OPTICAL SENSING AND DETECTION VI

Abstract
Long Period Fibre Gratings (LPFGs) were fabricated by femtosecond (fs) laser direct writing in a standard single-mode fibre (SMF-28e) to measure variations in the surrounding refractive index (SRI). The sensing sensitivity of these structures was optimized with the deposition of homogeneous thin layers of titanium dioxide (TiO2) by physical vapour deposition (PVD) process. A set of LPFGs were coated with different thickness layers of TiO2, and the spectral features were monitored for different SRI solutions. The wavelength shift and the optical power variation of the LPFG minimum attenuation band were measured achieving sensitivities of similar to 570 nm/RIU at using SRI near to 1.3600 in the case of the LPFG coated with 60 nm of TiO2, a 10-fold increase over the corresponding for a bare LPFG. For SRI values higher than the cladding refractive index, a sensitivity over similar to 3000 nm/RIU was determined for 30 nm of TiO2 thick film, a region where the bare LPFGs are useless. For 30 nm of TiO2, the optical power variation follows a quasi-linear function of the SRI, with a range of similar to 10 dB. Moreover, values as high as 50 and 120 dB/RIU at 1.3200 and 1.4200, respectively, can be obtained by choosing the proper film thickness. Preliminary studies revealed that coating fs-laser direct writing LPFGs with titanium dioxide improves their performance.

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