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14. Influence of oxygen deficiency on optical and dielectric properties of La0.75Ba0.10Sr0.15FeO2.875-δ compounds

Author

Bouzayen, M., Dhahri, R., Benali, A., Chaabouni, S., Khirouni, K., and Costa, B.F.O.

Subjects
Optical property, Oxygen vacancy, Sol gel method, Dielectric constant
Abstract

Using the conventional sol-gel process, the series of non-stoichiometric oxygen lanthanum ferrites with the formula 𝐿𝑎0.75𝐵𝑎0.10𝑆𝑟0.15𝐹𝑒𝑂2.875 ― 𝛿(δ=0.00, 0.125 and 0.25) were prepared. X-ray diffraction analysis confirmed the formation of the orthorhombic structure with Pnma space group. In the present work, we confirm the potential of 𝐿𝑎0.75𝐵𝑎0.10𝑆𝑟0.15𝐹𝑒 𝑂2.875 ― 𝛿(δ=0.00, 0.125 and 0.25) as an efficient dielectric material. All samples show high absorbance in the visible region with wavelength above 300 nm. The optical band gaps are found to increase from 3.25 to 4.1 with increasing oxygen vacancy concentration. The dielectric constant, dielectric loss and loss factor were carried out as a function of oxygen vacancy concentration and frequency (102 -106 Hz) at room temperature. The variation of dielectric constant with frequency indicates dispersive behavior and giant dielectric response (more than 104 ) at low frequencies for compounds deficient in oxygen. Such value of makes 𝜀′ these samples an interesting material to be used in applications namely the reduction of electronic components size. To summarize, incorporating vacancy oxygen enhances the dielectric properties. Thus, the interesting dielectric constant and weak loss strengthen the use for potential applications. published

Published
2020

15. Fermented camel milk by Lactococcus lactis subsp. cremoris attenuates erythrocytes oxidative stress-induced hematological and immunological damage in CCl4-intoxicated mice

Author

Dhouib K, Ghannoudi Z, Chaabouni S, El Feki A, Houda Hamed, Ali Gargouri, and Chaari F

Subjects
0301 basic medicine, Immunoglobulin A, Antioxidant, Health, Toxicology and Mutagenesis, medicine.medical_treatment, CCL4, Pharmacology, medicine.disease_cause, digestive system, Immunoglobulin G, Lipid peroxidation, 03 medical and health sciences, chemistry.chemical_compound, 0302 clinical medicine, parasitic diseases, medicine, Environmental Chemistry, biology, Lactococcus lactis subsp cremoris, Lactococcus lactis, General Medicine, biology.organism_classification, Pollution, 030104 developmental biology, chemistry, 030220 oncology & carcinogenesis, biology.protein, Oxidative stress
Abstract

Fermented camel by Lactococcus lactis subsp. cremoris has been recently discovered to protect against the toxic effect of carbon tetrachloride (CCl4), but its beneficial effects in the presence of oxidative stress in the erythrocytes have not been established. In the present study, 28 mice were randomly divided into four groups: control group; CCl4 group: intoxicated by a single intraperitoneal injection (ip) of CCl4; group FCM-LLC + CCl4: pretreated with FCM-LLC daily during 14 days, and received a single dose of CCl4. FCM-LLC group received FCM-LLC alone. The occurrence of oxidative stress in erythrocytes was evidenced by an increase in lipid peroxidation, protein carbonyl, and changes in antioxidant enzyme activities and non-enzymatic antioxidant. The oxidative injury induced by CCl4 in the erythrocytes was confirmed by modifications in hematological parameters and decreases in protein, albumin, and globulin content in the serum of intoxicated mice. Therefore, CCl4 caused a significant decrease in immunotoxic indices, including immunoglobulin G (IgG), immunoglobulin M (Ig M), and immunoglobulin A (IgA) levels, and an increase of inflammatory markers such as C-reactive protein (CRP) level. Meanwhile, FCM-LLC effectively restored the parameters cited above to near-normal values. It can be suggested that fermented camel milk could regulate deviant physiological effects induced by CCl4 which is due to its powerful antioxidant and immunomodulatory and anti-inflammatory capacity.

Published
2018

21. Analysis of the electrical transport, conductivity, and dielectric relaxation behavior of La0.75 Ba0.10 Sr0.15 Fe O2.875-δ (δ = 0.375 and 0.50) brownmillerite oxides.

Author

Bouzayen, M., Dhahri, R., Saadi, M., Chaabouni, S., Khirouni, K., and Costa, Benilde F. O.

Subjects
DIELECTRIC relaxation, ELECTRIC measurements, DIELECTRIC properties, DIELECTRIC measurements, DIELECTRIC loss
Abstract

The topotactic reduction of La0.75Ba0.10Sr0.15FeO2.875 with titanium metal leads to a new isostructural material of the composition La0.75Ba0.10Sr0.15FeO2.875-δ (δ = 0.375 and 0.50). XRD analysis of phases confirms that the obtained compound adopts a brownmillerite-type structure. A slight distorted monoclinic P2/m was found to describe the crystal structure. The transport properties have been investigated by current–voltage (I–V). The electric and dielectric measurements were carried out covering a wide range of temperature (300–600 K). Our materials display semiconducting properties as well as mixed ionic and electronic conductivity. At high temperatures, the activation energy values proved to be around 907–630 meV, which refers basically to oxygen vacancies conduction. The analysis of dielectric properties and dielectric losses (ε', tanδ) of both compounds vs temperature at different frequencies demonstrates two relaxer attitudes. A low dielectric loss and low electrical conductance were displayed. Relying upon these values, these materials stand for perfect candidates for micro-electronics devices. [ABSTRACT FROM AUTHOR]

Published
2021
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25. Structural, Electrical and Dielectric of Fe-Doped CaMn1−xFexO3−0.5x (x = 0.0 and 0.20).

Author

Tahri, T., Omri, A., Hamdaoui, N., Benali, A., Hcini, S., Gammoudi, I., Dhahri, E., and Chaabouni, S.

Subjects
ELECTRIC impedance, RIETVELD refinement, DIELECTRICS, UNIT cell, RELAXATION phenomena
Abstract

This work focuses on the structural and electrical properties of CaMn1−xFexO3−0.5x (x = 0.0 and 0.20) perovskite compounds prepared using the ceramic method. XRD patterns confirm the formation of the orthorhombic structure with Pnma space group for the samples, and Rietveld method was used to estimate their different structural parameters. Refinement results show that the cell parameters and unit cell volume increase with increasing Fe content. The complex impedance spectroscopy technique was used to investigate the frequency and temperature dependence of electrical conductance and electrical impedance. The total conductance curves of the sample are found to obey Jonscher power law GT(ω) = Gdc + Gac = Gdc + Aωn with an increase in frequency exponent (n) as temperature increases. Electrical impedance results show the presence of the electrical relaxation phenomenon for the samples. The activation energy deduced from the analysis of the conductance curves matches very well with the value estimated from the relaxation time, indicating that relaxation process and electrical conductivity are attributed to the same defect. The Nyquist representations have been analyzed using a proposed electrical circuit, and the results show that the grain boundary contribution is responsible to the conduction mechanism of the prepared samples. [ABSTRACT FROM AUTHOR]

Published
2019
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28. Photochemistry of ortho-Azidocinnamoyl Derivatives: Facile and Modular Synthesis of 2-Acylated Indoles and 2-Substituted Quinolines under Solvent Control.

Author

Chaabouni, S., Pinkerton, N. M., Abid, S., Galaup, C., and Chassaing, S.

Subjects
*PHOTOCHEMISTRY, *CINNAMOYL compounds, *HETEROCYCLIC compounds synthesis, *INDOLE
Abstract

The light-promoted potential of ortho-azidocinnamoyl compounds is evaluated for heterocycle synthesis. Depending on the nature of the solvent, 2-acylated indoles were obtained under aprotic conditions, whereas the use of a protic medium led to 2-substituted quinolines. The synthetic significance of this metal-free method is that, by simply changing the solvent, the reaction outcome can be directed towards different key heterocyclic scaffolds. [ABSTRACT FROM AUTHOR]

Published
2017
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35. Syndrome de Shulman de l’enfant

Author

Hamdi, W., primary, Haouel, M., additional, Chaabouni, S., additional, Chelli Bouaziz, M., additional, Ghannouchi, M.-M., additional, Ladeb, M.-F., additional, and Kchir, M.-M., additional

Published
2012
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37. Embolie pulmonaire hydatique chez un enfant

Author

Ellouze, S., primary, Bahri, M., additional, Abdennadher, M., additional, Kossentini, M., additional, Abid, N., additional, Chaabouni, S., additional, Khabir, A., additional, and Boudawara, T., additional

Published
2011
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