Determination of free formaldehyde in foundry resins as its 2,4-dinitrophenylhydrazone by liquid chromatography

Formaldehyde is a toxic component that is present in foundry resins. Its quantification is important to the characterisation of the resin (kind and degradation) as well as for the evaluation of free contaminants present in wastes generated by the foundry industry. The complexity of the matrices considered suggests the need for separative techniques. The method developed for the identification and quantification of formaldehyde in foundry resins is based on the determination of free carbonyl compounds by derivatization with 2,4-dinitrophenylhydrazine (DNPH), being adapted to the considered matrices using liquid chromatography (LC) with UV detection. Formaldehyde determinations in several foundry resins gave precise results. Mean recovery and R.S.D. were, respectively, >95 and 5%. Analyses by the hydroxylamine reference method gave comparable results. Results showed that hydroxylamine reference method is applicable just for a specific kind of resin, while the developed method has good performance for all studied resins.

Chromatographic techniques for the determination of free phenol in foundry resins

Phenol is a toxic compound present in a wide variety of foundry resins. Its quantification is important for the characterization of the resins as well as for the evaluation of free contaminants present in foundry wastes. Two chromatographic methods, liquid chromatography with ultraviolet detection (LC-UV) and gas chromatography with flame ionization detection (GC-FID), for the analysis of free phenol in several foundry resins, after a simple extraction procedure (30 min), were developed. Both chromatographic methods were suitable for the determination of phenol in the studied furanic and phenolic resins, showing good selectivity, accuracy (recovery 99–100%; relative deviations <5%), and precision (coefficients of variation <6%). The used ASTM reference method was only found to be useful in the analysis of phenolic resins, while the LC and GC methods were applicable for all the studied resins. The developed methods reduce the time of analysis from 3.5 hours to about 30 min and can readily be used in routine quality control laboratories.

Determination of ochratoxin A in bread: evaluation of microwave-assisted extraction using an orthogonal composite design coupled with response surface methodology

An analytical method using microwave-assisted extraction (MAE) and liquid chromatography (LC) with fluorescence detection (FD) for the determination of ochratoxin A (OTA) in bread samples is described. A 24 orthogonal composite design coupled with response surface methodology was used to study the influence of MAE parameters (extraction time, temperature, solvent volume, and stirring speed) in order to maximize OTA recovery. The optimized MAE conditions were the following: 25 mL of acetonitrile, 10 min of extraction, at 80 °C, and maximum stirring speed. Validation of the overall methodology was performed by spiking assays at five levels (0.1–3.00 ng/g). The quantification limit was 0.005 ng/g. The established method was then applied to 64 bread samples (wheat, maize, and wheat/maize bread) collected in Oporto region (Northern Portugal). OTAwas detected in 84 % of the samples with a maximum value of 2.87 ng/g below the European maximum limit established for OTA in cereal products of 3 ng/g.

Enantiomeric fraction evaluation of pharmaceuticals in environmentalmatrices by liquid chromatography-tandem mass spectrometry

The interest for environmental fate assessment of chiral pharmaceuticals is increasing and enantioselective analytical methods are mandatory. This study presents an enantioselective analytical method for the quantification of seven pairs of enantiomers of pharmaceuticals and a pair of a metabolite. The selected chiral pharmaceuticals belong to three different therapeutic classes, namely selective serotonin reuptake inhibitors (venlafaxine, fluoxetine and its metabolite norfluoxetine), beta-blockers (alprenolol, bisoprolol, metoprolol, propranolol) and a beta2-adrenergic agonist (salbutamol). The analytical method was based on solid phase extraction followed by liquid chromatography tandem mass spectrometry with a triple quadrupole analyser. Briefly, Oasis® MCX cartridges were used to preconcentrate 250 mL of water samples and the reconstituted extracts were analysed with a Chirobiotic™ V under reversed mode. The effluent of a laboratory-scale aerobic granular sludge sequencing batch reactor (AGS-SBR) was used to validate the method. Linearity (r2 > 0.99), selectivity and sensitivity were achieved in the range of 20–400 ng L−1 for all enantiomers, except for norfluoxetine enantiomers which range covered 30–400 ng L−1. The method detection limits were between 0.65 and 11.5 ng L−1 and the method quantification limits were between 1.98 and 19.7 ng L−1. The identity of all enantiomers was confirmed using two MS/MS transitions and its ion ratios, according to European Commission Decision 2002/657/EC. This method was successfully applied to evaluate effluents of wastewater treatment plants (WWTP) in Portugal. Venlafaxine and fluoxetine were quantified as non-racemic mixtures (enantiomeric fraction ≠ 0.5). The enantioselective validated method was able to monitor chiral pharmaceuticals in WWTP effluents and has potential to assess the enantioselective biodegradation in bioreactors. Further application in environmental matrices as surface and estuarine waters can be exploited.

Determinantes à receptividade ao bluetooth marketing pelo consumidor português

Dissertação de Mestrado apresentada ao Instituto Superior de Contabilidade e Administração do Porto para a obtenção do grau de Mestre em Marketing Digital, sob orientação do Mestre Paulo Gonçalves e da Doutora Madalena Vilas Boas Esta versão não contém as críticas e sugestões dos elementos do júri

Descending pain modulation in a Kaolin-induced hydrocephalus rat model

Pain transmission at the spinal cord is modulated by descending actions that arise from supraspinal areas which collectively form the endogenous pain control system. Two key areas involved of the endogenous pain control system have a circunventricular location, namely the periaqueductal grey (PAG) and the locus coeruleus (LC). The PAG plays a crucial role in descending pain modulation as it conveys the input from higher brain centers to the spinal cord. As to the LC, it is involved in descending pain inhibition by direct noradrenergic projections to the spinal cord. In the context of neurological defects, several diseases may affect the structure and function of the brain. Hydrocephalus is a congenital or acquired disease characterized by an enlargement of the ventricles which leads to a distortion of the adjacent tissues, including the PAG and LC. Usually, patients suffering from hydrocephalus present dysfunctions in learning and memory and also motor deficits. It remains to be evaluated if lesions of the periventricular brain areas involved in pain control during hydrocephalus may affect descending pain control and, herein, affect pain responses. The studies included in the present thesis used an experimental model of hydrocephalus (the rat injected in the cisterna magna with kaolin) to study descending modulation of pain, focusing on the two circumventricular regions referred above (the PAG and the LC). In order to evaluate the effects of kaolin injection into the cisterna magna, we measured the degree of ventricular dilatation in sections encompassing the PAG by standard cytoarquitectonic stanings (thionin staining). For the LC, immunodetection of the noradrenaline-synthetizing enzyme tyrosine hydroxylase (TH) was performed, due to the noradrenergic nature of the LC neurons. In general, rats with kaolin-induced hydrocephalus presented a higher dilatation of the 4th ventricle, along with a tendency to a higher area of the PAG. Due to the validated role of detection the c-fos protooncogene as a marker of neuronal activation, we also studied neuronal activation in the several subnuclei which compose the PAG, namely the dorsomedial, dorsolateral, lateral and ventrolateral (VLPAG) parts. A decrease in the numbers of neurons immunoreactive for Fos protein (the product of activation of the c-fos protooncogene) was detected in rats injected with kaolin, whereas the remaining PAG subnuclei did not present changes in Fos-immunoreactive nuclei. Increases in the levels of TH in the LC, namely at the rostral parts of the nucleus, were detected in hydrocephalic animals. The following pain-related parameters were measured, namely 1) pain behavioural responses in a validated pain inflammatory test (the formalin test) and 2) the nociceptive activation of spinal cord neurons. A decrease in behavioral responses was detected in rats with kaolin-induced hydrocephalus was detected, namely in the second phase of the test (inflammatory phase). This is the phase of the formalin test in which the motor behaviour is less important, which is important since a semi-quantitative analysis of the motor performance of rats injected with kaolin indicates that these animals may present some motor impairments. Collectively, the results of the behavioral studies indicate that rats with kaolin-induced hydrocephalus exhibit hypoalgesia. A decrease in Fos expression was detected at the superficial dorsal layers of the spinal cord in rats with kaolin-induced hydrocephalus, further indicating that hydrocephalus decreases nociceptive responses. It remains to be ascertained if this is due to alterations in the PAG and LC in the rats with kaolin-induced hydrocephalus, which may affect descending pain modulation. It remains to be evaluated what are the mechanisms underlying the increased pain inhibition at the spinal dorsal horn in the hydrocephalus rats. Regarding the VLPAG, the decrease in neuronal activity may impair descending modulation. Since the LC has higher levels of TH in rats with kaolininduced hydrocephalus, which also appears to increase the noradrenergic innervation in the spinal dorsal horn, it is possible that an increase in the release of noradrenaline at the spinal cord accounts for pain inhibition. Our studies also determine the need to study in detail patients with hydrocephalus namely in what concerns their thresholds to pain and to perform imaging studies focused on the structure and function of pain control areas in the brain.

Estudo da extração e caracterização de compostos bioativos a partir de casca, farelo e arroz de variedades portuguesas

O arroz é o alimento básico para milhões de pessoas no Mundo inteiro. Como tal, o seu valor nutricional é algo de extrema importância. Contudo, ao seu processamento está associado um desperdício dos resíduos que advêm do seu descasque e branqueamento, o farelo e a casca. O principal objetivo deste trabalho consistiu no estudo do valor nutricional do grão de arroz e da valorização dos resíduos (farelo e casca) através da avaliação da atividade antioxidante. O estudo foi aplicado a três frações do bago de arroz: grão, farelo e casca, de três subvariedades diferentes: opale, ariete e ellebi. Foi avaliado o perfil de macronutrientes nas amostras de arroz, entre eles o teor de humidade, cinza, proteína e gordura. O grão foi a fração que apresentou maior teor de humidade, o farelo a que apresentou maior teor de gordura e proteína e a casca maior teor de cinza. Os compostos bioativos foram extraídos pelo método de extração sólido-liquido, usando como solvente uma mistura aquosa de metanol. A caracterização dos compostos antioxidantes dos extratos foi analisada através do teste da eliminação dos radicais livres de DPPH (2,2-difenil-1-picrilhidrazilo) e pelo método de Folin-Ciocalteau. Para a identificação dos compostos bioativos foi utilizada a técnica de UPLC-PDA (Cromatografia líquida de ultra eficiência - Detetor de matriz de Fotodíodos). A casca foi o extrato que continha uma maior capacidade antioxidante e um maior conteúdo de fenólicos totais (TPC), e o extrato do grão o que apresentou menor valor. Identicamente, foi na casca onde se conseguiu identificar um maior número de compostos, entre os quais se destacam os ácidos gentísico, isoferúlico, vanílico, elágico, p-cumárico e levulínico. A extração de compostos antioxidantes de farelo e casca de arroz demonstrou ser uma via bastante promissora para a valorização destes resíduos.

Study of glycosidic changes in lung cancer: potential effectors in hematogenous metastasis

RESUMO: O cancro do pulmão (LC), uma das principais causas de mortalidade relacionada com cancro em Portugal, pode levar à formação de metástases hematogénicas. A adesão das células tumorais ao endotélio é considerada um dos passos fundamentais envolvidos na metástase. Em células sanguíneas, esta adesão é mediada por ligandos de E-selectina (E-SL), glicoproteínas ou glicolípidos decorados principalmente com sialyl-Lewis x (sLex) e sialyl-Lewis a (sLea). Tem sido descrito a expressão destes antigénios em LC, contudo o seu papel funcional em permitir a adesão das células de LC ao endotélio é ainda pouco compreendido. Foram analisadas amostras emparelhadas normais e tumorais de pacientes com cancro de pulmão de não-pequenas células (NSCLC) e três linhas celulares de LC. Immunoblotting assays com anti-sLex/sLea e molécula quimérica de E-selectina demonstraram que tecidos tumorais de LC sobreexpressam significativamente E-SL e resultados de citometria de fluxo demonstraram uma expressão elevada de E-SL nas linhas celulares. Para compreender o mecanismo da sobreexpressão de E-SL em tecidos tumorais e linhas celulares de LC, foi analisada a expressão de genes envolvidos na biossíntese de E-SL, nomeadamente FUT3, FUT4, FUT6, FUT7, ST3GAL3, ST3GAL4, ST3GAL6, β4GALT1, GCNT1 e GALNT3. Observou-se a sobreexpressão das fucosiltransferases FUT3, FUT6 e FUT7 em tecidos tumorais de LC e FUT3 em linhas celulares de LC, sendo que neste último, esta expressão é correlacionada com um aumento da adesão das células de LC às selectinas endoteliais. Foi observado que uma baixa expressão de FUT4 em tecidos tumorais está associada com estadios menos avançados de NSCLC. Foram analisadas ainda proteínas decoradas com sLex/sLea, tendo-se identificado como E-SL o antigénio carcinoembrionário em NSCLC. Em resumo, esta tese contribuiu para uma melhor compreensão das alterações glicosídicas e moléculas que podem influenciar a progressão tumoral do LC, podendo permitir identificar futuramente novos biomarcadores de diagnóstico/prognóstico e potenciais alvos terapêuticos para o NSCLC.--------------------------ABSTRACT: Lung cancer (LC), one of the major causes of mortality related to cancer in Portugal, may lead to hematogenous metastasis. Adhesion of cancer cells to endothelium is considered one of the crucial steps involved in metastasis. In blood cells, this adhesion is initiated by endothelial selectin ligands (E-SL) that are glycoproteins or glycolipids decorated mostly with sialyl-Lewis x (sLex) and sialyl-Lewis a (sLea). While LC has been described as expressing these sialyl Lewis antigens, its functional role in allowing LC adhesion to endothelium is still poorly understood. We analyzed paired tumor and normal tissues samples from non-small cell lung cancer (NSCLC) patients and three LC cell lines. Immunoblotting assays with anti-sLex/sLea and E-selectin chimera demonstrated that LC tumor tissues significantly overexpress E-SL and flow cytometry results indicated that E-SL are also abundantly expressed in LC cell lines. To understand the mechanism behind the overexpression of E-SL in LC tissues and cell lines, we analyzed the expression of genes involved in its biosynthesis, namely FUT3, FUT4, FUT6, FUT7, ST3GAL3, ST3GAL4, ST3GAL6, β4GALT1, GCNT1 and GALNT3. It was observed the overexpression of fucosyltransferases FUT3, FUT6 and FUT7 in LC tumor tissues and FUT3 in LC cell lines, being this last one correlated with an increased reactivity of the LC cells to endothelial selectins. It was described that low expression of FUT4 in tumor tissues is correlated with early stages of NSCLC. We also analyzed scaffolds proteins of sLex/sLea and it was identified the carcinoembryonic antigen as an E-SL in NSCLC. In summary, this thesis contributed to a better understanding of the glycosidic changes and molecules that can influence tumor progression of LC, allowing identifying in the future new diagnosis/prognosis biomarkers and potential therapeutic targets for NSCLC.

Pruebas preliminares sobre toxicidad aguda del cobre en la Concha de Abanico (Argopecten purpuratus)

Se realizaron siete bioensayos estáticos con la Concha de Abanico (Argopecten purpuratus) con concentraciones de cobre que variaron de 0.007 a 0.74 ppm. El agua de mar de donde provinieron los individuos usados en el experimento tenía concentraciones de cobre entre 0.005-0.007 ppm. La bioacumulación inicial en los animales varó de 1.69 a 6.50 ppm. Como resultado preliminar se determinó que 0.13 ppm es la concentración letal media (LC 50) en 96 horas.

Revue des travaux scientifiques / publ. sous la dir. du Comité des travaux historiques et scientifiques

1884 (T4).

Revue des travaux scientifiques / publ. sous la dir. du Comité des travaux historiques et scientifiques

1888 (T8).

Revue des travaux scientifiques / publ. sous la dir. du Comité des travaux historiques et scientifiques

1893 (T13).

Revue des travaux scientifiques / publ. sous la dir. du Comité des travaux historiques et scientifiques

1881 (T1).

Revue des travaux scientifiques / publ. sous la dir. du Comité des travaux historiques et scientifiques

1882 (T2).

Revue des travaux scientifiques / publ. sous la dir. du Comité des travaux historiques et scientifiques

1885 (T5).