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Alarcon M.,United Nations Educational | Ben Lakhdar Z.,Tunis el Manar University | Culaba I.,Ateneo de Manila University | Lahmar S.,Institute Preparatoire aux Etudes Scientifiques et Techniques | And 4 more authors.
Proceedings of SPIE - The International Society for Optical Engineering

Based on physics education goals adopted at the 2005 World Conference on Physics and Sustainable Development, the workshop on "Active learning in optics and photonics (ALOP)" has been described as a model for teacher training and professional development. This paper describes the basic philosophy and elements of the workshop and how it has served physics teachers in schools and introductory college/university in the developing world. Its main philosophy of fostering modern hands-on learning techniques-- adapted to local culture, needs and availability of teaching resources-- is elaborated. The workshop provides the participants with a conceptual evaluation instrument, drawn from relevant physics education research, giving teachers an important tool to measure student learning. © 2010 SPIE. Source

Samti R.,Institute Preparatoire aux Etudes Scientifiques et Techniques | Raouafi F.,CNRS Institute of Chemistry | Chaouach M.,Institute Preparatoire aux Etudes Scientifiques et Techniques | Maaref M.,Institute Preparatoire aux Etudes Scientifiques et Techniques | And 4 more authors.
Applied Physics Letters

Band structure calculations of complete InAs monolayer in AlGaAs/GaAs quantum wells are performed within the framework of the extended-basis sp 3d 5s * tight-binding model. We show that the optical properties can be tuned from the quantum well energy below the GaAs band-gap depending on the well thickness and the position of the probe. The results are supported by differential reflectivity measurements and represent a concept for optoelectronic devices with an operation wavelength widely tuneable around 850 nm employing GaAs process technology. © 2012 American Institute of Physics. Source

Ellouze I.,Institute National Agronomique Of Tunisie | Ellouze I.,Institute Preparatoire aux Etudes Scientifiques et Techniques | Debbabi H.,Institute National Agronomique Of Tunisie | Jamoussi B.,CNRS Institute of Chemistry | And 2 more authors.
Acta Horticulturae

Sour orange Citrus aurantium L. is a well known tree as a Citrus rootstock, as well as for its flowers. These flowers are full of essential oil which are stored in essence glands. When they withdraw water-distillation they produce an essential oil Neroli as well as orange blossom water distillate. The present work focused on studying orange blossom water composition variation during extraction by steam distillation. A liquid-liquid extraction by hexane was applied on various orange blossom water fractions, and then a GC allowed analysing them. The qualitative study revealed that major components for all fractions are linalol and α-terpineol. Those two elements represent 80% of the total composition of the first fractions. In contrast, for the last ones, there is an important decrease in amounts of these components for linalyl acetate and terpinolene. Source

Ben Marzoug H.N.,Institute Preparatoire aux Etudes Scientifiques et Techniques | Ben Marzoug H.N.,INSA Val de Loire | Bouajila J.,CNRS Laboratory for Molecular and Photochemical Reactions | Ennajar M.,INSA Val de Loire | And 5 more authors.
Journal of Medicinal Food

Essential oils of four different Eucalyptus species (Eucalyptus salubris, Eucalyptus salmonophloia, Eucalyptus oleosa, and Eucalyptus gracilis) grown in southern Tunisia were screened for their antioxidant and antimicrobial properties as well as their chemical compositions. According to gas chromatography-flame ionization detection and gas chromatography-mass spectrometry analysis, chemical compositions of the Eucalyptus species E. salubris (27 compounds; 99.2%), E. salmonophloia (31 compounds; 99.2%), E. oleosa (32 compounds; 97.6%), and E. gracilis (18 compounds; 97.7%) were identified. In the 1,1-diphenyl-2-picrylhydrazyl assay, the antioxidant activity was in the range of 12.0-52.8 mg/mL, whereas in the 2,2′-azinobis-3- ethylbenzothiazoline-6-sulfonate assay, E. oleosa (176.5 ± 3.1 mg/L) gave the best inhibition result. To evaluate antimicrobial activity, all essential oils were tested against bacteria (two Gram-positive and two Gram-negative), two yeast, and two fungi. Essential oils exhibited an interesting antibacterial activity against all microorganisms tested (activity was better against Gram-positive bacteria) except for Staphylococcus aureus and Escherichia coli. Correlations between chemical composition and biological and antioxidant activities were studied. © Mary Ann Liebert, Inc. Source

Ellouze I.,CNRS Laboratory for Molecular and Photochemical Reactions | Ellouze I.,Institute Preparatoire aux Etudes Scientifiques et Techniques | Abderrabba M.,Institute Preparatoire aux Etudes Scientifiques et Techniques | Sabaou N.,Laboratoire Of Recherche Sur Les Produits Bioactifs Et La Valorisation Of La Biomasse | And 3 more authors.
Journal of Food Science

Citrus aurantium leaves' essential oils (EOs) were evaluated for chemical composition and antioxidant and antibacterial activities. The vegetable material, taken 5 times during the year, has undergone the hydrodistillation to prepare EO. Chemical characterization by gas chromatography/mass spectrometry and GC/flame ionization detection allowed the identification of 46 compounds, and a notable quantitative and qualitative differences between the different Petitgrain samples according to the harvest time. Linalool (43.2% to 65.97%), linalyl acetate (0.77% to 24.77%), and α-terpineol (9.29% to 12.12%) were the main components. The most important number of components was registered for summer EOs (July and September). The 5 EOs submitted biological activities screening, namely, antioxidant and antimicrobial activities. Weak antioxidant activities (IC50 values >10000 mg/L) were registered by both 1,1-diphenyl-2-picrylhydrazyl and 2,2′-azinobis-3-ethylbenzothiazoline-6-sulphonate assays, mostly because the weak amount of phenols in EOs. Antibacterial activities (12 microorganisms) were registered against Gram-positive bacteria [Bacillus subtilis (MIC = 2.7 mg/mL), Staphylococcus aureus (4.8 mg/mL)], and moderated ones against yeasts [Saccharomyces cerevisiae (9.2 mg/mL)] and fungi [Mucor ramannianus (5 mg/mL)]. Positive correlations between the identified compounds and the antimicrobial activities were noted. Many compounds were correlated to antimicrobial activity mainly caryophyllene oxide against Escherichia coli (R2= 0.99), S. cerevisiae (R2= 0.99), and Fusarium culmorum (R2= 0.99). © 2012 Institute of Food Technologists®. Source

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