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Publicações

Publicações por CAP

2021

Label-Free Anti-Human IgG Biosensor Based on Chemical Modification of a Long Period Fiber Grating Surface

Autores
Mendes, JP; Coelho, LCC; Pereira, VP; Azenha, MA; Jorge, PAS; Pereira, CM;

Publicação
Chemistry Proceedings

Abstract
This work introduces a method specially developed to produce a biorecognition element based on modified Stöber silica nanoparticles by the covalent immobilization of the human IgG. The sensing structure is based on long period fiber gratings (LPFG), specially developed to allow the interaction of the electromagnetic wave with the target analytes through its evanescent field. The surface was modified by the immobilization of the IgG-modified nanoparticles serving has recognition elements for specific target molecules. The resulting configuration was tested in the presence of anti-human IgG, recording the refractometric response of the modified LPFG in contact with different amounts of analyte. The selectivity of the sensor was also assessed.

2021

Optical Biosensor for the Detection of Hydrogen Peroxide in Milk

Autores
Vasconcelos, H; Matias, A; Jorge, P; Saraiva, C; Mendes, J; Araújo, J; Dias, B; Santos, P; Almeida, JMMM; Coelho, LCC;

Publicação
Chemistry Proceedings

Abstract
Over the years, the food industry’s concern to provide safe food that does not cause harm or illness to consumers has increased. The growing demand for the detection of compounds that can contaminate food is increasingly important. Hydrogen peroxide is frequently used as a substance to control the growth of microorganisms in milk, thus increasing its shelf life. Here, a strategy is presented for the detection of hydrogen peroxide as a milk adulterant, using a single shot membrane sensor. The lowest concentration measured with this technique was 0.002% w/w of H2O2 in semi-fat milk.

2021

Hydroponics Monitoring through UV-Vis Spectroscopy and Artificial Intelligence: Quantification of Nitrogen, Phosphorous and Potassium

Autores
Silva, AF; Löfkvist, K; Gilbertsson, M; Os, EV; Franken, G; Balendonck, J; Pinho, TM; Boaventura-Cunha, J; Coelho, L; Jorge, P; Martins, RC;

Publicação
Chemistry Proceedings

Abstract
In hydroponic cultivation, monitoring and quantification of nutrients is of paramount importance. Precision agriculture has an urgent need for measuring fertilization and plant nutrient uptake. Reliable, robust and accurate sensors for measuring nitrogen (N), phosphorus (P) and potassium (K) are regarded as critical in this process. It is vital to understand nutrients’ interference; thusly, a Hoagland fertilizer solution-based orthogonal experimental design was deployed. Concentration ranges were varied in a target analyte-independent style, as follows: [N] = [103.17–554.85] ppm; [P] = [15.06–515.35] ppm; [K] = [113.78–516.45] ppm, by dilution from individual stock solutions. Quantitative results for N and K, and qualitative results for P were obtained.

2021

Hyperspectral Imaging System for Marine Litter Detection

Autores
Freitas, S; Silva, H; Almeida, C; Viegas, D; Amaral, A; Santos, T; Dias, A; Jorge, PAS; Pham, CK; Moutinho, J; Silva, E;

Publicação
OCEANS 2021: SAN DIEGO - PORTO

Abstract
This work addresses the use of hyperspectral imaging systems for remote detection of marine litter concentrations in oceanic environments. The work consisted on mounting an off-the-shelf hyperspectral imaging system (400-2500 nm) in two aerial platforms: manned and unmanned, and performing data acquisition to develop AI methods capable of detecting marine litter concentrations at the water surface. We performed the campaigns at Porto Pim Bay, Fail Island, Azores, resorting to artificial targets built using marine litter samples. During this work, we also developed a Convolutional Neural Network (CNN-3D), using spatial and spectral information to evaluate deep learning methods to detect marine litter in an automated manner. Results show over 84% overall accuracy (OA) in the detection and classification of the different types of marine litter samples present in the artificial targets.

2021

Optical Measurements

Autores
Cennamo N.; Jorge P.A.S.;

Publicação
IEEE Instrumentation and Measurement Magazine

Abstract

2021

Arc-Induced Long-Period Fiber Gratings at INESC TEC. Part I: Fabrication, Characterization and Mechanisms of Formation

Autores
Rego, G; Caldas, P; Ivanov, OV;

Publicação
SENSORS

Abstract
In this work, we reviewed the most important achievements of INESC TEC related to the fabrication of long-period fiber gratings using the electric arc technique. We focused on the fabrication setup, the type of fiber used, and the effect of the fabrication parameters on the gratings' transmission spectra. The theory was presented, as well as a discussion on the mechanisms responsible for the formation of the gratings, supported by the measurement of the temperature reached by the fiber during an electric arc discharge.

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