Cookies Policy
We use cookies to improve our site and your experience. By continuing to browse our site you accept our cookie policy. Find out More
Close
  • Menu
About

About

B.Sc. Chemistry, Universidade de Las Villas, Cuba, 1991 M.Sc. Organic Chemistry, Universidade de La Habana, Cuba, 2000 Ph.D. Material Science and Engineering, Aveiro, Portugal, 2007 3 cuban national prizes by work done in the isolation and detection of natural products

Interest
Topics
Details

Details

002
Publications

2016

Antimicrobial effect of essential oils of Laurus nobilis L. and Rosmarinus officinallis L. on shelf-life of minced "Maronesa" beef stored under different packaging conditions

Authors
Vilela, J; Martins, D; Monteiro Silva, F; Gonzalez Aguilar, G; de Almeida, JMMM; Saraiva, C;

Publication
FOOD PACKAGING AND SHELF LIFE

Abstract
The aim of this study was to evaluate the effect of essential oils (EOs) of plants naturally occurring in northern Portugal on the spoilage of fresh Maronesa beef burgers stored at 2 and 8 degrees C under different packaging conditions. EOs were obtained from dried leaves of laurel (Laurus Nobilis L.) and rosemary (Rosmarinus officinallis L.) by hydro-distillation using a Clevenger-type apparatus. Analysis of volatile composition of essential oils of rosemary and laurel was achieved by Gas Chromatography-Mass Spectrometry (GC-MS) and Gas Chromatography-Thermal Conductivity Detection (GC-TCD) resulting in the detection of 95.8% and 89.4% of its compounds, respectively. Fresh beef (semitendinosus and semimembranosus) of DOP-Maronesa breed (males; n = 4) were obtained from local market and transported to the laboratory. Samples were stored at 2 and 8 degrees C in two different conditions: aerobiosis (A) and vacuum (V) and analyzed at 0,1, 2, 3, 5, 7,10,14, 21 and 28 days for Lactic acid bacteria (LAB), Enterobacteriaceae, Pseudomonas spp., Fungi, Total mesophilic (TM) and psychrotrophic (TP), color (L*a*b*) and pH. Laurel was the most effective EO keeping pH from increasing. Coordinates L* and a* were higher on samples containing laurel EO for both A and V packaging. Laurel also showed better effect in reducing microbiologic counts in samples packed in A at both 2 and 8 degrees C and packed in V at 8 degrees C. Rosemary was effective in reducing microbial counts on all V samples stored at 2 degrees C. This study allows to conclude that Laurel EO has significant effect in shelf-life, maintaining fresh beef color.

2013

Chemical sensing by differential thermal analysis with a digitally controlled fiber optic interferometer

Authors
Goncalves, LC; Gonzalez Aguilar, G; Frazao, O; Baptista, JM; Jorge, PAS;

Publication
REVIEW OF SCIENTIFIC INSTRUMENTS

Abstract
In this work the implementation of an optical fiber interferometric system for differential thermal analysis enabling the identification of chemical species is described. The system is based on a white light Mach-Zehnder configuration using pseudo-heterodyne demodulation to interrogate two identical fiber Bragg gratings (FBG) in a differential scheme. System performance is compared using either standard hardware or low cost virtual instrumentation for operation control and signal processing. The operation with the virtual system enabled temperature measurements with a +/-0.023 degrees C resolution nearly matching the performance of the standard hardware. The system ability to discriminate chemical species by differential thermal analysis was demonstrated. Mixed samples of acetone and methanol could be successfully identified, indicating the suitability of the system for high precision measurements using low cost instrumentation. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4774054]

2013

Electrochemical behaviour of ZnO/flavonoid pairs

Authors
Vilarica, MJ; Gonzalez Aguilar, G;

Publication
ENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY

Abstract
The last years are witnesses of continuous raise in the price of traditional fuels. This fact, joined to environmental concerns and the fears concerning the inevitable oil reserves depletion, has empowered the search for new energetic sources. Organic photovoltaic cells or Gratzel cells are a solution for collecting solar energy. Searching for new materials for this type of solar cells is normally a trial-and-error procedure. Assembling components to make a solar cell in the laboratory is a difficult and expensive task. In this work, the electrochemical behaviour of flavonoids that can be used as sensitizers in solar photovoltaic cells when in contact with a given semiconductor is studied. This procedure can simplify the process of pairing a dye with a semiconductor in order to obtain optimum performance when designing new photovoltaic cells. (c) 2012 American Institute of Chemical Engineers

2011

Microcystin-LR detection in water by the Fabry-Perot interferometer using an optical fibre coated with a sol-gel imprinted sensing membrane

Authors
Raquel Barbosa Queirós; Susana Oliveira Silva; J. P. Noronha; Orlando Frazão; Pedro Jorge; Gerardo Aguilar; Paulo Vicente Marques; M. G. F. Sales

Publication
BioS & BioElec - Biosensors and Bioelectronics, vol.26, no.9, pp.3932-3937

Abstract

2011

Synthesis of orthorhombic rare-earth manganite thin films by a novel chemical solution route

Authors
Yonny Romaguera; Joaquim Moreira; Gerardo Aguilar; Abilio Almeida; João Araujo; Javier Cruz

Publication
J. ELECTROCERAM. - Journal of Electroceramics, vol.26, no.1, pp.44-55

Abstract
A novel and general chemical solution route for processing high-quality transition metal and rare-earth orthorhombic manganite thin films on Pt(111)/Ti/SiO2/Si substrates was reported. The precursor solutions decomposition process of the manganites was studied by TG and DTA techniques, showing the formation of the phase above 650°C in LaMnO3 and 750°C in both EuMnO3 and DyMnO3 thin films. X-ray diffraction and Raman spectroscopic analysis reveal the formation of a pure orthorhombic structure, with a space group Pbnm, in LaMnO3, EuMnO3 and DyMnO3 thin films annealed at temperatures above the TG phase formation temperature observed. Microstructure and grain morphology of the films were analyzed by SEM and AFM techniques, showing a progressive improvement of the films structures with the increase of the annealing temperature. The temperature dependence of the magnetic response of the LaMnO3, EuMnO3 and DyMnO3 thin films show typical transition temperatures, compared with those reported for lanthanum, europium and dysprosium manganite single crystals and ceramics.