High‐Resolution X‐Ray Diffraction of III–V Semiconductor Thin Films

In this chapter, we will address the structural characterization of III–V semiconductor thin films by means of HRXRD. We first give an overview on the basic experimental apparatus and theory element of this method. Subsequently, we treat several examples in order to determine the effect of doping, composition and strain on structural properties of crystal. Analysed layers were grown by metal organic vapour phase epitaxy (MOVPE). Films treated as examples are selected in order to bring the utility of characterization technique. Here, we investigate GaAs/GaAs(0 0 1), GaAs:C/GaAs(0 0 1), GaN/Si(1 1 1), GaN:Si/Al2O3(0 0 1), GaAsBi/GaAs(0 0 1) and InGaAs/GaAs(0 0 1) heterostructures by using different scans for studying numerous structural layers and substrate parameters. Different scan geometries, such as ω‐scan, ω/2θ‐scan and map cartography, are manipulated to determine tilt, deformation and dislocation density induced by mismatch between layer and substrate. This mismatch is originated from the difference between the chemical properties of two materials generated by doping or alloying. Such HRXRD measurements are explored through the angular spacing between peaks of the substrate and layer. The half of full width maximum (HFWM) of peak layer intensity is a crucial qualitative parameter giving information on defect density in the layer

Variations in fatty acid composition during maturation of cumin (Cuminum cyminum L.) seeds

Changes in fatty acids were studied during maturation of cumin (Cuminum cyminum L.) seeds cultivated in the North-Eastern region of Tunisia (Menzel Temim). The fruits matured in 49 Days after flowering (DAF). The first results show a rapid oil accumulation started in newly formed fruits (8.2%) and continued until their full maturity (16.9%). During fruit maturation, fatty acid profiles varied significantly among the three stages of maturity. Fruits development resulted mainly in an increase of petroselinic acid and a decrease of palmitic acid (C16:0). At full maturity, the main fatty acids were petroselinic acid (55.9%), followed by palmitic (23.82%), linoleic (12.40%) and pamitoleic (2.12%) acids. Polyunsaturated and monounsaturated fatty acids increased significantly; however, saturated fatty acids decreased during ripening of cumin seed. Results of this study indicate that the variation in the fatty acid composition of cumin seeds during maturation may be useful in understanding the source of nutritionally and industrially important fatty acids in this fruit. Cumin seed is potentially an important source of petroselinic acid which has numerous industrial applications.Keywords: Cumin (Cuminum cyminum L.), Apiaceae, seed, fatty acids composition, petroselinic acid, maturation.African Journal of Biotechnology Vol. 12(34), pp. 5303-530

Existence of solutions in the alpha-norm for partial functional differential equations with infinite delay

In this work, we prove a result on the local existence of mild solution in the $\alpha$-norm for some partial functional differential equations with infinite delay. We suppose that the linear part generates a compact analytic semigroup. The nonlinear part is just assumed to be continuous. We use the compactness method, to show the main result of this work. Some application is provided

Phytochemical composition and antioxidant activity of Lavandula dentate extracts

Le but de ce travail consiste à étudier la composition des huiles essentielles et des polyphénols des racines, des tiges et des feuilles de la Lavande dentée et d’évaluer leurs potentialités antioxydantes. L’analyse et la quantification des huiles essentielles a montré que les feuilles sont les plus riches en huiles essentielles (0.89 mg/g MS) suivies par les tiges (0.68 mg/g MS) et enfin les racines (0,23 mg/g MS). Le constituant majeur de l’HE des racines est: le β-ocimène. D’autre part, le limonène représente le composé majeur de l’HE des tiges. Quant à l’HE des feuilles, elle est dominée par le camphre. D’autre part, nos résultats ont montré que les organes de la lavande montrent des teneurs en polyphénols totaux élevées et variables selon l’organe étudié. En effet, les extraits des racines sont caractérisés par le contenu le plus élevé en polyphénols. D’autre part, l’étude de l’activité antioxydante des extraits des différents organes a indiqué que les extraits de la racine sont particulièrement les plus actifs et que leur analyse par RP-HPLC a montré que ces derniers sont riches essentiellement en acide rosmarinique. Finalement, les extraits de la Lavande dentée et particulièrement ceux de la racine peuvent être considérés comme des sources alternatives d’antioxydants naturels puissants qui peuvent être utilisés en industrie agroalimentaire et pharmaceutique.In this study, Lavandula dentata organs (roots, stems and leaves) were investigated for their essential oils, total phenolics, flavonoids contents and antioxidant activities. Essential oil yields were 0.22% in roots, 0.68 % in stems and 0.89 % in flowers. Major components of the oils were β-ocimene, limonene and 1,8 cineol in roots, stems and leaves and flowers, respectively. In all organs, total phenolics content ranged from 42.57 to 16.17 mg gallic acid equivalents per gram of dry weight (mg GAE/g DW).The antioxidant activities of Lavandula dentata extracts obtained from the three organs were assessed using two tests (DPPH and reducing power). The root extract was strongly effective as DPPH radical scavenger and reducing agent. Thus, the identification of individual target polyphenolic compounds of roots was performed by RP-HPLC. The major phenolic compound detected in roots was rosmarinic acid. This activity was high enough for the plant to be a new and natural source of strongly antioxidant substances for use as natural additives in food and pharmaceutical industry

Antioxidant and antimicrobial phenolic compounds from extracts of cultivated and wild-grown Tunisian Ruta chalepensis

The antioxidant and antibacterial activities of phenolic compounds from cultivated and wild Tunisian Ruta chalepensis L. leaves, stems, and flowers were assessed. The leaves and the flowers exhibited high but similar total polyphenol, flavonoid, and tannin content. Moreover, two organs showed strong, although not significantly different, total antioxidant activity, 2,2-diphenyl-1-picrylhydrazyl scavenging ability, and reducing power. Investigation of the phenolic composition showed that vanillic acid and coumarin were the major compounds in the two organs, with higher percentages in the cultivated organs than in the spontaneous organs. Furthermore, R. chalepensis extracts showed marked antibacterial properties against human pathogen strains, and the activity was organ- and origin-dependent. Spontaneous stems had the strongest activity against Pseudomonas aeruginosa. From these results, it was concluded that domestication of Ruta did not significantly affect its chemical composition and consequently the possibility of using R. chalpensis organs as a potential source of natural antioxidants and as an antimicrobial agent in the food industry

Antioxidant and antimicrobial phenolic compounds from extracts of cultivated and wild-grown Tunisian Ruta chalepensis

Abstract The antioxidant and antibacterial activities of phenolic compounds from cultivated and wild Tunisian Ruta chalepensis L. leaves, stems, and flowers were assessed. The leaves and the flowers exhibited high but similar total polyphenol, flavonoid, and tannin content. Moreover, two organs showed strong, although not significantly different, total antioxidant activity, 2,2-diphenyl-1-picrylhydrazyl scavenging ability, and reducing power. Investigation of the phenolic composition showed that vanillic acid and coumarin were the major compounds in the two organs, with higher percentages in the cultivated organs than in the spontaneous organs. Furthermore, R. chalepensis extracts showed marked antibacterial properties against human pathogen strains, and the activity was organ- and origin-dependent. Spontaneous stems had the strongest activity against Pseudomonas aeruginosa . From these results, it was concluded that domestication of Ruta did not significantly affect its chemical composition and consequently the possibility of using R. chalpensis organs as a potential source of natural antioxidants and as an antimicrobial agent in the food industry

Does Lycium europaeum leaf have antihyperglycemic, antihyperlipidemic and antioxidant effects

The purpose of the present investigation is to assess, for the first time, the antidiabetic, antihyperlipidemic and antioxidant activities of Lycium europaeum extract in alloxan-induced diabetic rats. Diabetes was induced in adult male Wistar rats via a single subcutaneous alloxan injection (120 mg/kg). Lycium europaeum aqueous extract was orally administered at a dose of 20 mg/kg for 28 consecutive days. Serum concentrations of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglycerides (TG) were assayed at the end of the experimental period in all investigated groups. Antioxidant enzymes such as glutathione peroxidase (GPx), catalase (CAT) and superoxide dismutase (SOD) were sought in the serum and pancreas. Lycium europaeum extract significantly increased HDL-C and reduced blood glucose, TC, LDL-C and TG as compared to the alloxan-control group. Lycium europaeum extract was also efficient in reducing oxidative stress in diabetic rats by increasing SOD, CAT and GPx activities both in the pancreas and the plasma of the animals. Moreover, Lycium europaeum extract contained considerable levels of polyphenols and flavonoids. It also exhibited an important antioxidant capacity and a remarkable ability to quench DPPH radicals and reduce irons. The obtained results highlight potentially relevant health beneficial effects of Lycium europaeum extract, reversing hyperglycemic, hyperlipidemic and oxidative stress effects in rats with alloxan-induced diabetes. Therefore, it may be considered as a promising alternative or complementary agent to diabetes treatment

Influence of climate variation on phenolic composition and antioxidant capacity of Medicago minima populations

peer reviewedMedicago minima is a pasture legume that grows almost all over the world. In Tunisia, it occupies various climatic environments and is considered the most abundant annual Medicago plant. However, this species is unconsumed and unused by humans. This study aimed to explore the phytochemical characteristics of Medicago minima selected from diferent provenances in Tunisia and subsequently investigate the infuence of environmental factors on their phenolic composition and antioxidant activity. Therefore, a calorimetric method and DPPH tests provided the total phenolic and totalfavonoid contents and antioxidant potential in roots, stems, leaves and seeds. High performance liquid chromatography (HPLC) identifed and quantifed four phenolic acids and three favonoids in the studied organs. Roots and leaves showed the greatest phenolic compound content and had high antioxidant activity. Rutin and syringic acid (leaves) represent a characteristic for this species. For each organ, principal component analysis of phenolic profles showed that the root’s phenolic composition could be an indication of the plant adaptation to even small changes in its environments. Plants originating from a cold climate, higher altitude or semi-arid environment had the highest phenolic compound contents in their organs. Our fndings provide useful information for the exploitation of the phenolic compounds in these weeds for the development of environmental sustainability

Green Extraction of Fennel and Anise Edible Oils Using Bio-based Solvent and Supercritical Fluid: Assessment of Chemical Composition, Antioxidant Property and Oxidative Stability

The aim of this study was to evaluate the replacement aspects of conventional methods (petroleum-based solvent and Folch assay) by alternative methods (bio-based and biodegradable solvent 2-methyltetrahydrofuran (MeTHF) and supercritical CO2 (SC-CO2)) for seed oil extraction from anise (Pimpinella anisum L.) and fennel (Foeniculum vulgare Mill.). Results showed that the highest oil yield of aniseeds was obtained by using Folch (24.07%) and MeTHF (23.65%) extraction methods whereas fennel seeds had 20.02% and 18.72%, respectively. Fatty acid composition of both seed oils obtained by the two green extraction methods was similar to the conventional ones with the predominance of petroselinic acid (54.22–61.25% in fennel and 42.39– 48.97% in anise). Besides, SC-CO2 method allowed to obtain the maximum of sterol content in anise (3.85 mg/g of oil) and fennel (4.64 mg/g of oil) seed oils. Furthermore, anise and fennel seed oils extracted with MeTHF method significantly showed higher total phenolic content (2.43 and 1.32 mg GA/g oil, respectively), stronger antioxidant activity (9.23 and 5.04 μmol TEAC/g oil, respectively), and oxidative stability (8.23 and 10.15 h, respectively) than the other methods (p < 0.05). In conclusion, MeTHF appeared to be a good substitute to petroleum solvents for recovery of high oil quality from Pimpinella anisum and Foeniculum vulgare seeds.MESRS LR15CBBC0

Green Solvent to Substitute Hexane for Bioactive Lipids Extraction from Black Cumin and Basil Seeds

A comparative study of bioactive lipids extraction from black cumin (Nigella sativa L.) and basil (Ocimum basilicum L.) seeds using conventional petroleum-based solvent and green solvent 2-methyltetrahydrofuran (MeTHF) was performed. MeTHF extraction allowed obtaining the highest oil yield in black cumin (34%). Regarding fatty acids composition, linoleic acid (61%) and α-linolenic (78%) were relevant in black cumin and basil green and conventionally extracted oils, respectively. Besides, MeTHF allowed obtaining higher tocopherols and total phenolics contents in black cumin (400 mg/kg of oil and 12 mg EGA/g oil) and basil (317 mg/kg oil and 5 mg EGA/g oil) compared to hexane-extracted ones. The content of major phenolic compounds in the two seed oils, trans-hydroxycinnamic acid, rosmarinic acid, and thymol was enhanced by MeTHF extraction. Furthermore, MeTHF-extracted oils possess stronger antioxidant activities (radical scavenging, total antioxidant, and β-carotene bleaching activities) and high and similar anti-inflammatory capacity to hexane-extracted oils. In conclusion, the results revealed that MeTHF is efficient to replace hazardous solvents to extract oil from black cumin and basil seeds rich in compounds relevant to the human diet, including essential polyunsaturated fatty acids (n-6 and n-3), tocopherols, and phenolic compounds with improved biological activities.Peer reviewe