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Bordj Bou Arreridj, Algeria

Percario S.,Federal University of Para | Domingues S.P.D.T.,Anhanguera | Teixeira L.F.M.,Universitary Center | Vieira J.L.F.,Federal University of Para | And 4 more authors.
Journal of the International Society of Sports Nutrition | Year: 2012

Background: Creatine (Cr) supplementation has been widely used among athletes and physically active individuals. Secondary to its performance-enhancing ability, an increase in oxidative stress may occur, thus prompting concern about its use. The purpose of this study is to investigate the effects of Cr monohydrate supplementation and resistance training on muscle strength and oxidative stress profile in healthy athletes.Methods: A randomized, double-blind, placebo-controlled method was used to assess twenty-six male elite Brazilian handball players divided into 3 groups: Cr monohydrate supplemented group (GC, N = 9), placebo group (GP, N = 9), no treatment group (COT, N = 8) for 32 days. All subjects underwent a resistance training program. Blood samples were drawn on 0 and 32 days post Cr supplementation to analyze the oxidative stress markers, thiobarbituric acid reactive species (TBARS), total antioxidant status (TAS), and uric acid. Creatine phosphokinase, urea, and creatinine were also analyzed, as well. Fitness tests (1 repetition maximum - 1RM and muscle endurance) were performed on the bench press. Body weight and height, body fat percentage (by measuring skin folds) and upper muscular area were also evaluated. Statistical analysis was performed using ANOVA.Results: Only GC group showed increase in 1RM (54 ± 9 vs. 63 ± 10 kg; p = 0.0356) and uric acid (4.6 ± 1.0 vs. 7.4 ± 1.6 mg/dl; p = 0.025), with a decrease in TAS (1.11 ± 0.34 vs. 0.60 ± 0.19 mmol/l; p = 0.001). No differences (pre- vs. post-training) in TBARS, creatine phosphokinase, urea, creatinine, body weight and height, body fat percentage, or upper muscular area were observed in any group. When compared to COT, GC group showed greater decrease in TAS (-0.51 ± 0.36 vs. -0.02 ± 0.50 mmol/l; p = 0.0268), higher increase in 1RM (8.30 ± 2.26 vs. 5.29 ± 2.36 kg; p = 0.0209) and uric acid (2.77 ± 1.70 vs. 1.00 ± 1.03 mg/dl; p = 0.0276).Conclusion: We conclude that Cr monohydrate supplementation associated with a specific resistance program promoted a meaningful increase in muscle strength without inducing changes in body composition. The observed significant increase in uric acid and the decrease in TAS suggest that creatine supplementation, despite promoting acute effects on muscle strength improvement, might induce oxidative stress and decreases total antioxidant status of subjects. © 2012 Percário et al.; licensee BioMed Central Ltd. Source


Ghebouli B.,Ferhat Abbas University Setif | Ghebouli M.A.,Universitary Center | Fatmi M.,Ferhat Abbas University Setif
Physica B: Condensed Matter | Year: 2011

A theoretical study on the structural, elastic, electronic and lattice dynamic properties of Al xY yB 1-x-yN quaternary alloys in zinc-blend phase has been carried out with first-principles methods. Information on the lattice parameter, the lattice matching to available substrates and energy band-gaps is a prerequisite for many practical applications. The dependence of the lattice parameter a, bulk modulus B, elastic constants C 11, C 12 and C 44, band-gaps, optical phonon frequencies (ω TO and ω LO), the static and high-frequency dielectric coefficients ε (0) and ε (∞) and the dynamic effective charge Z were analyzed for y=0, 0.121, 0.241, 0.362 and 0.483. A significant deviation of the bulk modulus from linear concentration dependence was observed. A set of isotropic elastic parameters and related properties, namely bulk and shear moduli, Youngs modulus, Poissons ratio are numerically estimated in the frame work of the VoigtReussHill approximation. The resistance to changes in bond length and lateral expansion in Al xY yB 1-x-yN increase with increasing y concentration. We observe that at y concentration about 0.035 and 0.063, Al xY yB 1-x-yN changes from brittle to ductile and ΓX indirect fundamental gap becomes ΓΓ direct fundamental gap. There is good agreement between our results and the available experimental data for the binary compound AlN, which is a support for those of the quaternary alloys that we report for the first time. © 2011 Elsevier B.V. All rights reserved. Source


Fatmi M.,Ferhat Abbas University Setif | Ghebouli M.A.,Universitary Center | Ghebouli B.,Ferhat Abbas University Setif | Chihi T.,Ferhat Abbas University Setif | And 3 more authors.
Romanian Reports of Physics | Year: 2011

We present structural, elastic, electronic, optical and thermal properties of the cubic structure Ni3Al for various pressures. The computational method is based on the pseudo-potential plane wave (PP-PW). The exchange-correlation energy is described in both generalized gradient approximation (GGA) and the local-density approximation (LDA). The calculated equilibrium lattice parameter is in a reasonable agreement with the available experimental data. The value of Debye temperature obtained using elastic constants is about 466.49 K. Applied pressure does not change the shape of the total valence electronic charge density. The Fermi level is located in the part where the nickel contribution is very strong. Most of the electronic charge density is shifted toward Ni atoms. The coefficients of electronic and lattice heat capacities were calculated. Furthermore, in order to understand the optical properties of Ni3Al, the dielectric function, absorption coefficient, refractive index and extinction coefficient are calculated for radiation up to 80 eV. Source


Ghebouli M.A.,Universitary Center | Ghebouli B.,Ferhat Abbas University Setif | Fatmi M.,Ferhat Abbas University Setif
Physica B: Condensed Matter | Year: 2011

The structural, elastic, electronic, optical and thermal properties of the semiconductor perovskite CsPbCl3 were investigated using the pseudo-potential plane wave (PP-PW) scheme in the frame of generalized gradient approximation (GGA) and local density approximation (LDA). The computed lattice constant agrees reasonably with experimental and theoretical ones. The CsPbCl3 crystal behaves as ductile material. The valence bands are separated from the conduction bands by a direct band gap RR. We distinguished hybridization between Pb-p states and Cl-p states in the valence bonding region. Under compression at P=30 GPa, this material will have a metallic character. The thermal effect on the lattice constant, bulk modulus, Debye temperature and heat capacity CV was predicted using the quasi-harmonic Debye model. To the authors knowledge, most of the studied properties are reported for the first time. © 2011 Elsevier B.V. All rights reserved. Source


Ghebouli M.A.,Universitary Center | Ghebouli B.,Ferhat Abbas University Setif | Fatmi M.,Ferhat Abbas University Setif | Bouhemadou A.,Ferhat Abbas University Setif | Bouhemadou A.,King Saud University
Solid State Communications | Year: 2011

Various physical properties of the cubic perovskite-type oxide BiScO 3 have been investigated using the pseudo-potential plane-wave (PP-PW) method based on the density functional theory (DFT). The computed equilibrium lattice parameters agree well with the available theoretical data. The elastic constants and their pressure dependence are predicted using the static finite strain technique. A set of isotropic elastic parameters and related properties, namely bulk and shear moduli, Young's modulus, Poisson's ratio, average sound velocity and Debye temperature are numerically estimated in the framework of the VoigtReussHill approximation for BiScO3 polycrystalline aggregate. The analysis of the site-projected l-decomposed density of states, charge transfer and charge density shows that bonding is predominantly of ionic nature. We distinguish hybridization between Sc-d states and O-p states in the valence bonding region. Through the quasi-harmonic Debye model, in which the phononic effects are considered, the thermal effect on the lattice constant, bulk modulus, heat capacities and thermal expansion coefficient is calculated. © 2011 Elsevier Ltd. All rights reserved. Source

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