Browsing by Author "Delerue-Matos, Cristina"
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- 3D-nanostructured Au electrodes for the event-specific detection of MON810 transgenic maizePublication . Barroso, M. Fátima; Freitas, Maria; Oliveira, M. Beatriz P.P.; de-los-Santos-Álvarez, Noemí; Lobo-Castañón, María Jesús; Delerue-Matos, CristinaIn the present work, the development of a genosensor for the event-specific detection of MON810 transgenic maize is proposed. Taking advantage of nanostructuration, a cost-effective three dimensional electrode was fabricated and a ternary monolayer containing a dithiol, a monothiol and the thiolated capture probe was optimized to minimize the unspecific signals. A sandwich format assay was selected as a way of precluding inefficient hybridization associated with stable secondary target structures. A comparison between the analytical performance of the Au nanostructured electrodes and commercially available screen-printed electrodes highlighted the superior performance of the nanostructured ones. Finally, the genosensor was effectively applied to detect the transgenic sequence in real samples, showing its potential for future quantitative analysis.
- Accounting for the dissociating properties of organic chemicals in LCIA: an uncertainty analysis applied to micropollutants in the assessment of freshwater ecotoxicityPublication . Morais, Sérgio Alberto; Delerue-Matos, Cristina; Gabarrell, XavierIn life cycle impact assessment (LCIA) models, the sorption of the ionic fraction of dissociating organic chemicals is not adequately modeled because conventional non-polar partitioning models are applied. Therefore, high uncertainties are expected when modeling the mobility, as well as the bioavailability for uptake by exposed biota and degradation, of dissociating organic chemicals. Alternative regressions that account for the ionized fraction of a molecule to estimate fate parameters were applied to the USEtox model. The most sensitive model parameters in the estimation of ecotoxicological characterization factors (CFs) of micropollutants were evaluated by Monte Carlo analysis in both the default USEtox model and the alternative approach. Negligible differences of CFs values and 95% confidence limits between the two approaches were estimated for direct emissions to the freshwater compartment; however the default USEtox model overestimates CFs and the 95% confidence limits of basic compounds up to three orders and four orders of magnitude, respectively, relatively to the alternative approach for emissions to the agricultural soil compartment. For three emission scenarios, LCIA results show that the default USEtox model overestimates freshwater ecotoxicity impacts for the emission scenarios to agricultural soil by one order of magnitude, and larger confidence limits were estimated, relatively to the alternative approach.
- Acetylated cashew gum-based nanoparticles for the incorporation of alkaloid epiisopiloturinePublication . Rodrigues, Jessica do Amaral; Araújo, Alyne Rodrigues de; Pitombeira, Nadia Aline; Plácido, Alexandra; Almeida, Miguel Peixoto de; Veras, Leiz Maria Costa; Delerue-Matos, Cristina; Lima, Filipe Camargo Dalmatti Alves; Neto, Augusto Batagin; Paula, Regina Célia Monteiro de; Feitosa, Judith Pessoa Andrade; Eaton, Peter; Leite, José Roberto Souza A.; Silva, Durcilene Alves daThe natural alkaloid epiisopiloturine has recently become the focus of study for various medicinal properties, particularly for its anti-inflammatory and antischistosomal effect. The incorporation of active molecules in natural polymeric matrices has garnered increasing interest during recent decades. A new derivative of cashew gum successfully obtained by gum acetylation has shown great potential as a carrier in controlled drug release systems. In this work, epiisopiloturine was encapsulated in acetylated cashew gum nanoparticles in order to increase solubility and allow slow release, whereas the morphology results were supported by computer simulations. The particles were produced under a variety of conditions, and thoroughly characterized using light scattering and microscopic techniques. The particles were spherical and highly stable in solution, and showed drug incorporation at high levels, up to 55% efficiency. Using a dialysis-based in vitro assay, these particles were shown to release the drug via a Fickian diffusion mechanism, leading to gradual drug release over approximately 6 h. These nanoparticles show potential for the use as drug delivery system, while studies on their potential anti-inflammatory action, as well as toxicity and efficacy assays would need to be performed in the future to confirm their suitability as drug delivery candidates.
- Adipose tissue dysfunction as a central mechanism leading to dysmetabolic obesity triggered by chronic exposure to p,p’-DDEPublication . Pestana, Diogo; Teixeira, Diana; Meireles, Manuela; Marques, Cláudia; Norberto, Sónia; Sá, Carla; Fernandes, Virgínia; Correia-Sá, Luísa; Faria, Ana; Guardão, Luísa; Guimarães, João T.; Cooper, Wendy N.; Sandovici, Ionel; Domingues, Valentina; Delerue-Matos, Cristina; Monteiro, Rosário; Constância, Miguel; Calhau, ConceiçãoEndocrine-disrupting chemicals such as p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE), are bioaccumulated in the adipose tissue (AT) and have been implicated in the obesity and diabetes epidemic. Thus, it is hypothesized that p,p'-DDE exposure could aggravate the harm of an obesogenic context. We explored the effects of 12 weeks exposure in male Wistar rats' metabolism and AT biology, assessing a range of metabolic, biochemical and histological parameters. p,p'-DDE -treatment exacerbated several of the metabolic syndrome-accompanying features induced by high-fat diet (HF), such as dyslipidaemia, glucose intolerance and hypertension. A transcriptome analysis comparing mesenteric visceral AT (vAT) of HF and HF/DDE groups revealed a decrease in expression of nervous system and tissue development-related genes, with special relevance for the neuropeptide galanin that also revealed DNA methylation changes at its promoter region. Additionally, we observed an increase in transcription of dipeptidylpeptidase 4, as well as a plasmatic increase of the pro-inflammatory cytokine IL-1β. Our results suggest that p,p'-DDE impairs vAT normal function and effectively decreases the dynamic response to energy surplus. We conclude that p,p'-DDE does not merely accumulate in fat, but may contribute significantly to the development of metabolic dysfunction and inflammation. Our findings reinforce their recognition as metabolism disrupting chemicals, even in non-obesogenic contexts.
- Adsorption behavior of α-cypermethrin on cork and activated carbonPublication . Domingues, Valentina F.; Priolo, Giuseppe; Alves, Arminda; Cabral, Miguel; Delerue-Matos, CristinaStudies were undertaken to determine the adsorption behavior of α-cypermethrin [R)-α-cyano-3-phenoxybenzyl(1S)-cis- 3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate, and (S)-α-cyano-3-phenoxybenzyl (1R)-cis-3-(2,2-dichlorovinyl)-2,2- dimethylcyclopropanecarboxylate] in solutions on granules of cork and activated carbon (GAC). The adsorption studies were carried out using a batch equilibrium technique. A gas chromatograph with an electron capture detector (GC-ECD) was used to analyze α-cypermethrin after solid phase extraction with C18 disks. Physical properties including real density, pore volume, surface area and pore diameter of cork were evaluated by mercury porosimetry. Characterization of cork particles showed variations thereby indicating the highly heterogeneous structure of the material. The average surface area of cork particles was lower than that of GAC. Kinetics adsorption studies allowed the determination of the equilibrium time—24 hours for both cork (1–2 mm and 3–4 mm) and GAC. For the studied α-cypermethrin concentration range, GAC revealed to be a better sorbent. However, adsorption parameters for equilibrium concentrations, obtained through the Langmuir and Freundlich models, showed that granulated cork 1–2 mm have the maximum amount of adsorbed α-cypermethrin (qm) (303 μg/g); followed by GAC (186 μg/g) and cork 3-4 mm (136 μg/g). The standard deviation (SD) values, demonstrate that Freundlich model better describes the α-cypermethrin adsorption phenomena on GAC, while α-cypermethrin adsorption on cork (1-2 mm and 3-4 mm) is better described by the Langmuir. In view of the adsorption results obtained in this study it appears that granulated cork may be a better and a cheaper alternative to GAC for removing α-cypermethrin from water.
- Adsorption of Fluoxetine and Venlafaxine onto the Marine Seaweed Bifurcaria bifurcataPublication . Silva, Andreia; Stawiński, Wojciech; Romacho, Juan; Santos, Lúcia H.M.L.M.; Figueiredo, Sónia; Freitas, Olga; Delerue-Matos, CristinaMarine macroalga Bifurcaria bifurcata was investigated as sorbent for two environmental emerging pollutants, the pharmaceuticals venlafaxine (VLF) and fluoxetine (FLX), from aqueous solutions, both in mono and bicomponent batch systems. The alga was characterized by means of IR spectroscopy, allowing to identify the most important groups for biosorption, carboxylic, sulfonic and hidroxile. The point of zero charge was determined, being 6.4. Adsorption of FLX follows a pseudo first order kinetics and kinetic constants are higher for FLX than for VLF. Its adsorption better represented by the pseudo second order model. For both pharmaceuticals, the equilibrium was reached within *100 min. Adsorption studies reveal that the process was more efficient at lower pH range and followed the Langmuir–Freundlich’s model for VLF and Langmuir’s model for FLX. Maximum adsorption capacities reached a level of 12 – 3 and 22 – 4 lmol/g for VLF and FLX, respectively, in the mono-component system. The difference was attributed to the presence of various functional groups of varying polarity within the adsorbates’ molecules that affected their interactions with the adsorbent surface. The Langmuir–Freundlich’s extended model was applied to the adsorption data of the bicomponent system and no changes in the maximum adsorption capacities were found (14 – 2 and 20 – 3 lmol/g for VLF and FLX, respectively), there is no evidence of competition between the adsorbates.
- Adsorptive stripping voltammetric determination of venlafaxine in urine with a mercury film microelectrodePublication . Morais, Simone; Ryckaert, Christine P. M. C. A.; Delerue-Matos, CristinaAn adsorptive stripping voltammetric procedure for the determination of the antidepressant venlafaxine in urine using a mercury film microelectrode wasdeveloped. The method is based on controlled adsorptive accumulation of the drug at the potential of 1.00V (vs. Ag/AgCl) in the presence of 1.25 x10 -2 molL- 1 borate buffer (pH 8.7). Urine samples were analyzed directly after performing a ten-fold dilution with the supporting electrolyte but without other pretreatment. The limit of detection obtained for a 30 s collection time was 0.693x 10- 6 mol L -1. Recovery experimentsgave good results at the 10 -6 mol L- 1 level (bias less 5% were obtained).
- Advantages of structural inspection and diagnosis for traditional buildings’ refurbishment: A Life Cycle Assessment perspectivePublication . Silva, Renata; Surra, Elena; Quelhas, Bruno; Costa, Alexandre A.; Lapa, Nuno; Delerue-Matos, CristinaThis work demonstrated, through Life Cycle Assessment (LCA), the environmental advantages brought by the application of the Structural Inspection and Diagnosis (SID) methodology to the structural refurbishment of 7 traditional buildings located in the city of Porto (Portugal), when compared to the common total demolition and reconstruction approach. The early diagnosis of the conservation state of the existing structural elements, and their characterization provides fundamental information for optimizing the design of the refurbishment towards environmental sustainability. SID approach can reduce by 75.3%, on average, the demolished material and provide the lowest environmental burdens in the environmental categories of Global Warming, Acidification, Eutrophication, Ozone, and Abiotic Depletion, Photochemical Ozone Creation potential, Human Toxicity as well as Energy Demand when compared with the total demolition and reconstruction scenarios. In terms of relative environmental impact for the reconstruction scenarios, it was concluded that reinforced concrete, in the form of lightweight and solid slabs, presents the worst performance due to the concrete production process. Furthermore, timber structures show better environmental performance when compared to the use of glued laminated timber. The establishment of the SID tool as a consolidated methodology can be a unique opportunity to systematically include, in the refurbishment of traditional buildings, the principles of the environmental sustainability required by EU policies in the construction sector, providing a significant reduction of demolition wastes and the maximization of the preservation of existing structural materials.
- Agar extraction from integrated multitrophic aquacultured Gracilaria vermiculophylla: Evaluation of a microwave-assisted process using response surface methodologyPublication . Sousa, Ana M. M.; Alves, V. D.; Morais, Simone; Delerue-Matos, Cristina; Gonçalves, Maria PilarMicrowave-assisted extraction (MAE) of agar from Gracilaria vermiculophylla, produced in an integrated multitrophic aquaculture (IMTA) system, from Ria de Aveiro (northwestern Portugal), was tested and optimized using response surface methodology. The influence of the MAE operational parameters (extraction time, temperature, solvent volume and stirring speed) on the physical and chemical properties of agar (yield, gel strength, gelling and melting temperatures, as well as, sulphate and 3,6-anhydro-Lgalactose contents) was evaluated in a 2^4 orthogonal composite design. The quality of the extracted agar compared favorably with the attained using traditional extraction (2 h at 85ºC) while reducing drastically extraction time, solvent consumption and waste disposal requirements. Agar MAE optimum results were: an yield of 14.4 ± 0.4%, a gel strength of 1331 ± 51 g/cm2, 40.7 ± 0.2 _C gelling temperature, 93.1 ± 0.5ºC melting temperature, 1.73 ± 0.13% sulfate content and 39.4 ± 0.3% 3,6-anhydro-L-galactose content. Furthermore, this study suggests the feasibility of the exploitation of G. vermiculophylla grew in IMTA systems for agar production.
- Air pollution from traffic emissions in Oporto, Portugal: health and environmental implicationsPublication . Slezakova, Klara; Castro, Dionísia; Begonha, Arlindo; Delerue-Matos, Cristina; Alvim-Ferraz, Maria da Conceição M.; Morais, Simone; Pereira, Maria do CarmoAir pollution represents a serious risk not only to environment and human health, but also to historical heritage. In this study, air pollution of the Oporto Metropolitan Area and its main impacts were characterized. The results showed that levels of CO, PM10 and SO2 have been continuously decreasing in the respective metropolitan area while levels of NOx and NO2 have not changed significantly. Traffic emissions were the main source of the determined polycyclic aromatic hydrocarbons (PAHs; 16 PAHs considered by U.S. EPA as priority pollutants, dibenzo[a,l]pyrene and benzo[j]fluoranthene) in air of the respective metropolitan area. The mean concentration of 18 PAHs in air was 69.9±39.7 ng m−3 with 3–4 rings PAHs accounting for 75% of the total ΣPAHs. The health risk analysis of PAHs in air showed that the estimated values of lifetime lung cancer risks considerably exceeded the health-based guideline level. Analytical results also confirm that historical monuments in urban areas act as passive repositories for air pollutants present in the surrounding atmosphere. FTIR and EDX analyses showed that gypsum was the most important constituent of black crusts of the characterized historical monument Monastery of Serra do Pilar classified as “UNESCO World Cultural Heritage”. In black crusts, 4–6 rings compounds accounted approximately for 85% of ΣPAHs. The diagnostic ratios confirmed that traffic emissions were the major source of PAHs in black crusts; PAH composition profiles were very similar for crusts and PM10 and PM2.5.