Acute Toxicity of Perfluorooctane Sulfonic Acid on Early Life Stages of Daphnia Magna, Siriella Armata, Paracentrotus Lividus Sea Urchin, and Turbot (Scophthalmus Maximus L.).

Perfluorooctane sulfonate (PFOS) is a persistent organic pollutant whose potential toxicity is causing great concern. In the present study, we used two crustaceans (_Daphnia magna_, _Siriella armata_), echinoid embryos (_Paracentrotus lividus_) and turbot (_Scophthalmus maximus L._) embryos and larvae to investigate the acute toxicity of this compound. The marine species _S. armata_ exhibited greater sensitivity than the freshwater species _D. magna_. In the 48-h acute toxicity test the median lethal concentration was 10.96 mg/L for _S. armata_ and 87.46 mg/L for _D. magna_. In the 96h toxicity test, turbot showed the lowest EC50 (0.155 mgL-1), whilst the EC50 for _S. armata_ was 7.92 mgL-1 which was approximately three times lower than that for sea urchin (24.12 mgL-1). The EC10 values were estimated as 0.032 mgL-1, 4.23 mgL-1 and 45.21 mgL-1 for turbot, Siriella and daphnia, respectively. The LOEC values were 75 µgL-1, 2.5 mgL-1 and 75 mgL-1 (p< 0.05) for turbot, daphnia, and Siriella, respectively. The NOEC values were estimated at 37.5 µgL-1, 1.25 mgL-1 and 50 mgL-1 (p< 0.05) for turbot, Siriella and daphnia, respectively. The order of acute toxicity was: turbot > _S. armata_ > sea urchin > _Daphnia magna_. This result highlights the importance of including a marine fish in the battery of species to describe the toxicity of these compounds. Considering the persistent nature of PFOS, more research is required to determine potential consequences of long-term exposure to these compounds in aquatic ecosystems

Chemical and biological analysis of Tramazeira

Mestrado de dupla diplomação com a Université Libre de TunisRowanberries also called as Sorbus aucuparia L. fruits (Tramazeira fruits in Portugal), an ornamental tree, have been traditionally used in various processed foods due to their high relevance to human health. Scientific research demonstrates the nutritional effects of Sorbus L. fruits are determined by their unique composition of chemically and biologically active compounds. The extraction of phenolic compounds from Tramazeira fruits is of interest because they can be used as natural food additives but, extractive processes must be optimized to ensure that the relevant levels of all phenolic compounds groups are extracted from fruit pulp (lyophilized). A central composite design with two factors (percentage of Ethanol and pH values) was applied, with ethanol % in the range of 24.6 to 95.4% and pH between 0.9 and 5.1. From the response surface methodology (RSM) data treatment, the selected hydroethanolic extract solution had pH value of 3 and ethanol % of 85%, which allowed to have high amounts of the three main groups of phenolic compounds: flavonoids, hydroxybenzoic acids and hydroxycinnamic acids. Extracts of Tramazeira (Sorbus L.) fruit were applied as an additive in orange fresh juice and showed antimicrobial activity against gram positive and gram-negative bacteria, being more effective against gram-positive bacteria. The time effect on orange juice with the different concentrations of the Tramazeira fruit extract showed influence on the microbiological quality of the orange juice. However, the results suggest that the juices obtained with the highest concentration are more stable from a microbiological point of view.A fruta Tramazeira também chamada de Sorbus aucuparia L., uma árvore ornamental, tem sido tradicionalmente usada em vários alimentos processados devido à sua grande relevância para a saúde humana. Trabalhos científicas demonstram que os efeitos nutricionais das frutas Sorbus L. são determinados por sua composição única de compostos química e biologicamente ativos. A extração de compostos fenólicos dos frutos da Tramazeira é interessante porque podem ser usados como aditivos alimentares naturais, mas os processos extrativos devem ser otimizados para garantir que os níveis relevantes de todos os grupos de compostos fenólicos sejam extraídos da polpa do fruto (liofilizada). Foi aplicado um desenho compósito central com dois fatores (percentagem de etanol e valores de pH), com % de etanol na faixa de 24,6 a 95,4% e pH entre 0,9 e 5,1. A partir do tratamento dos dados com a metodologia de superfície de resposta, a solução extractora hidroetanólica selecionada apresentava valor de pH de 3 e % de etanol de 85%, o que permitiu ter quantidades elevadas dos três grupos principais de compostos fenólicos: flavonóides, ácidos hidroxibenzóico e ácidos hidroxicinâmicos . Extratos da fruta Tramazeira (Sorbus L.) foram aplicados como aditivo em sumo fresco de laranja e apresentaram atividade antimicrobiana contra bactérias gram-positivas e gramnegativas, sendo mais eficazes contra bactérias gram-positivas. O efeito do tempo nos sumos de laranja com as concentrações do extrato da fruta Tramazeira mostrou influência na qualidade microbiológica do sumo de laranja. No entanto, os resultados sugerem que os sumos obtidos com as maiores concentrações são mais estáveis do ponto de vista microbiológico

Exact Solutions for Nonlinear Partial Differential Equations: A Fusion of Classical Methods and Innovative Approaches

This article demonstrates how variation of parameters can be successfully implemented in combination with other classical techniques, such as the method of characteristics, to derive novel classes of solutions to nonlinear partial differential equations (NLPDES) by considering specific initial conditions. This innovative approach offers the advantage of generating exact solutions. The results underscore this method's potential to address additional NLPDE classes.Comment: 15 pages, 24 figure

Étude et développement d'un simulateur numérique pour la distribution variable du moteur diesel

RÉSUMÉ : Les effets néfastes des émissions des automobiles sur l'environnement ont entraîné des restrictions sévères afin de le préserver. Les difficultés rencontrées lors de l'amélioration du rendement du moteur Diesel, résultent principalement de son fonctionnement inefficace à différents régimes. La distribution variable peut être une alternative d'amélioration de ces moteurs grâce à la réduction de la consommation de carburant, et l'amélioration des performances. Cette étude sera consacrée à l'expérimentation de cette distribution grâce à une approche base sur une simulation numérique en utilisant le logiciel GT-POWER. Cela va être réalisé essentiellement grâce à des simulations de variation de levé de soupape et de l'angle de l'ouverture et de la fermeture de soupape selon le régime. La première partie sera consacrée à l'étude des moteurs diesel. Ensuite, nous allons passer à une modélisation du circuit d'admission et d'échappement. Puis, la troisième partie sera dédiée à la conception des techniques de distribution variable. Enfin, nous allons réaliser une évaluation du moteur Diesel. -- Mot(s) clé(s) en français : moteur diesel, distribution variable, modélisation 1D, performances, GT-Power. -- ABSTRACT : The harmful effects of automobile emissions on the environment have resulted in severe restrictions in order to preserve it. The difficulties encountered in improving the efficiency of the diesel engine, mainly result from its inefficient operation at different speeds. Variable valve timing can be an alternative to improving these engines by reducing fuel consumption, and improving performance. This study will be devoted to the experimentation of this distribution using an approach based on a numerical simulation using the GT-POWER software. This will be achieved primarily through simulations of the variation in valve lift and the angle of valve opening and closing according to rpm. The first part will be devoted to the study of diesel engines. Next, we will move on to modeling the intake and exhaust system. Then, the third part will be dedicated to the design of variable distribution techniques. Finally, we will carry out an evaluation of the Diesel engine. -- Mot(s) clé(s) en anglais : diesel engine, variable timing, 1D modeling, performance, GT-Power

Toxicity of three selected pesticides (Alachlor, Atrazine and Diuron) to the marine fish (turbot Psetta maxima)

The present study aimed to evaluate acute toxicity tests for three selected herbicides: Alachlor, Atrazine and Diuron using turbot flatfish. Larvae were more sensitive than turbot embryos to all pesticides. Median lethal concentrations of the selected pesticides during a 48 h and 96 h exposure for turbot embryos and larvae were, respectively: alachlor, 2177 and 2233; diuron, 10076 and 7826 and atrazine, 11873 and 9957 μg/L. On the basis of the obtained acute toxicity data, all compounds were included among substances highly toxic to fish, in the following order: alachlor> atrazine> diuron. At higher concentrations, pesticides caused a significant increase in embryo mortality. Surviving organisms suffered a significant decrease in hatching success, malformations (embryos), pericardial oedema and skeletal deformation (larvae). All herbicides appear to be teratogenic to the turbot early life stage. Furthermore, the three selected pesticides differed in their toxicity to the fish.Keywords: Turbot, early life stage, acute toxicity, sublethal effects, herbicide