Satellite cells and myonuclei in young and elderly women and men

The overall aim of this study was to assess the effects of aging on the satellite cell population. Muscle biopsies were taken from the tibialis anterior muscle of healthy, moderately active young (age range, 20-32 years; n = 31) and elderly (age range, 70-83 years; n = 27) women and men with comparable physical activity pattern. Satellite cells and myonuclei were visualized using a monoclonal antibody against neural cell adhesion molecule and counterstained with Mayer's hematoxylin. An average of 211 (range, 192-241) muscle fibers were examined for each individual. Compared with the young women and men, the elderly subjects had A significantly lower (P < 0.011) number of satellite cells per muscle fiber but a significantly higher (P < 0.004) number of myonuclei per muscle fiber. The number of satellite cells relative to the total number of nuclei [satellite cells/(myonuclei + satellite cells)] was significantly lower in the elderly than in the young women and men. These results imply that a reduction in the satellite cell population occurs as a result of increasing age in healthy men and women

Electronic structure, phase stability, and vibrational properties of Ir-based intermetallic compound IrX (X=A1, Sc, and Ga)

WOS: 000346952600017The phase stability and mechanical properties of B2 type IrX (X=Al, Sc and Ga) compounds are investigated. Self-consistenttotal-energy calculations in the framework of density functional theory using the Generalized Gradient Approximation (GGA) to determine the equations of state and the elastic constants of IrX (X=Al, Sc, and Ga) in the B2 phase have been performed. The calculations predicted the equilibrium lattice constants, which are about 1% greater than experiments for IrAl, 1.81% for IrGa, and 0.71% for IrSc compound. IrAl is shown to be the least compressible, and it is followed by IrGa and the IrSc compound. The phase stability of the studied compounds is checked. The brittleness and ductility properties of IrX (X=Al, Sc, and Ga) are determined by Poisson's ratio sigma criterion and Pugh's criterion. IrGa compound is a ductile material; however, IrAl and IrSc show brittleness. The band structure and density of states (DOS), and phonon dispersion curves have been obtained and analyzed. The position of the Fermi level and the contribution of d electrons to the density of states near E-F is studied and discussed in detail. We also used the phonon density of states and quasiharmonic approximation to calculate and predict some thermodynamic properties such as constant-volume specific heat capacity of the B2 phase of IrX (X=Al, Sc and Ga) compounds. (C) 2014 Elsevier Ltd. All rights reserved.Ahi Evran University Research Project UnitAhi Evran University [PYO-EGF.4001.14.003]This work was supported by the Ahi Evran University Research Project Unit under Project no: PYO-EGF.4001.14.003

A first-principle study of Os-based compounds: Electronic structure and vibrational properties

WOS: 000378960700016The electronic structure, elastic, and phonon properties of OsM (M=Hf, Ti, Y and Zr) compounds are studied using first-principles calculations. Elastic constants of OsY and specific heat capacity of OsM (M=Hf, Ti, Y, and Zr) are reported for the first time. The predicted equilibrium lattice constants are in excellent agreement with experiment. The calculated values of bulk moduli are considerably high but are much smaller than that of Osmium, which is around 400 GPa. The phase stability of the OsM (M=Hf, Ti, Y and Zr) compounds were studied by DOS calculations and the results suggest that OsY is unstable in the B2 phase. The brittleness and ductility properties of OsM (M=Hf, Ti, Y and Zr) are determined. OsM (M=Hf, Ti, Y and Zr) compounds are predicted to be ductile materials. The electronic structure and phonon frequency curves of OsM (M=Hf, Ti, Y and Zr) compounds are obtained. The position of Fermi level of these systems was calculated and discussed in terms of the pseudo gaps. The finite and small DOS at the Fermi level 0.335, 0.375, 1.063, and 0.383 electrons/eV for OsHf, OsTi, OsY, and OsZr, respectively, suggest that OsM (M=Hf, Ti, Y and Zr) compounds are weak metals. (C) 2016 Elsevier Ltd. All rights reserved.Czech Science FoundationGrant Agency of the Czech Republic [13-03708S]This work was supported by the Czech Science Foundation, Project no. 13-03708S. The authors thank to Mariana Klementova for simulations in programme JEMS

Electronic structure, optical and thermodynamic properties of ternary hydrides MBeH3 (M = Li, Na, and K)

WOS: 000383768200010Electronic band structure, optical and thermodynamic properties of ternary hydrides MBeH3 (M = Li, Na, and K) were studied using ab initio density functional theory (DFT). The effect of the adopted approximation to the exchange-correlation functional of the DFT is explicitly investigated by considering four different expressions of two different classes (local-density approximation and generalized-gradient approximation). The calculated magnitude of B classifies MBeH3 (M = Li, Na, and K) as easily compressible materials. The bonding interaction in these compounds is quite complicated. The interaction between M and BeH6 is ionic and that between Be and H comprises both ionic and covalent characters. The electronic structure of the complex hydride was investigated by calculating the partial and total densities of states, and electron charge density distribution. Large gaps in the density of states appear at the Fermi energy of LiBeH3, NaBeH3, and KBeH3 indicating that these classes of hydrides are insulators. Optical properties, including the dielectric function, reflectivity, and absorption coefficient, each as a function of photon energy, are calculated and show an optical anisotropy for LiBeH3 and KBeH3. Through the quasi-harmonic Debye model, in which the phononic effects are considered, temperature dependence of volume V(T), bulk modulus B(T), and thermal expansion coefficient alpha(T), constant-volume and constant-pressure specific heat (C-v and C-p) and Debye temperature Theta(D), the entropy S, and the Gruneisen parameter gamma were calculated at wide pressure and temperature ranges. The principal aspect of the obtained results is the close similarity of MBeH3 (M = Li, Na, and K) compounds.Algerian University research project (CNEPRU) [D05620140014]This work is supported by the Algerian University research project (CNEPRU) under grant No. D05620140014

The antioxidant activity of two Algerian plants belonging to the Ericaceae family

info:eu-repo/semantics/nonPublishe

Electronic and phonon properties of the full-Heusler alloys X2YAl (X = Co, Fe and Y = Cr, Sc): a density functional theory study

WOS: 000334074000007First-principle calculations have been carried out on the structural, electronic, elastic, and phonon properties of the full-Heusler alloys X2YAl (X = Co, Fe and Y = Cr, Sc). The calculations predict that the Fe2CrAl and Co2CrAl are half-metallic ferromagnets at the equilibrium lattice constant with a minority-spin energy gap of 0.2912 and 0.668 eV, respectively. Fe2ScAl exhibit a gap in the majority density of states, with a few states at the Fermi level and about 0.217 states eV(-1), unlike the other Heusler compounds; due to this, it is considered a false half metal, and Co2ScAl is considered a non-magnetic compound. The elastic constants were derived from the slopes of the acoustic branches in the phonon-dispersion curve. The calculated lattice constants, bulk modulus, and first-order pressure derivative of the bulk modulus are reported for the L2(1) structure and compared with previous values. Phonon-dispersion curves were obtained using the first-principle linear-response approach of the density-functional perturbation theory. The specific heat capacity at a constant volume C (V) of X2YAl (X = Co, Fe and Y = Cr, Sc) alloys is calculated and discussed.Gazi University Research Project UnitGazi University [05/2012-07, 05/201208, 05/2012-62, 05/2012-63]; Ahi Evran University Research Project UnitAhi Evran University [PYO.EGF.4001.13.002]This work was supported by the Gazi University Research Project Unit under Project No 05/2012-07, 05/201208, 05/2012-62, 05/2012-63 and the Ahi Evran University Research Project Unit under Project No. PYO.EGF.4001.13.002

Structural, elastic, electronic and phonon properties of scandium-based compounds ScX3 (X = Ir, Pd, Pt and Rh): An ab initio study

WOS: 000324471100090Self-consistent band calculations on four compounds of the L1(2) structure are presented. The structural, elastic, electronic and phonon properties of ScX3 (X = Ir, Pd, Pt and Rh) compounds within density functional theory have been investigated. The calculated lattice constants for those compounds are in good agreement with the available theoretical and experimental values. The elastic constants (C-11, C-12 and C-44) in L1(2) phase for ScX3 (X = Ir, Pd, Pt and Pd) compounds are calculated using the energy-strain method. These calculated elastic constants satisfy the mechanical stability criterion and the ductility of ScX3 (X = Ir, Pd, Pt and Rh) is predicted by Pugh's criterion. The band structure and density of states (DOS), and phonon dispersion curves have been obtained and compared with the available results as well as with existing theoretical calculations. The present band structure calculations predict that the L1(2)-ScX3 (X = Ir, Pd, Pt and Pd) compounds are metals. Finally specific heat at constant volume versus temperature is calculated and discussed using the quasi harmonic approximation. (C) 2013 Elsevier B.V. All rights reserved.Ahi Evran University Research Project UnitAhi Evran University [FBA-11-29]; Gazi University Research Project UnitGazi University [05/2012-62, 05/2012-63, 05/2012-07, 05/2012-08]This work was supported by the Ahi Evran University Research Project Unit under Project No. FBA-11-29 and the Gazi University Research Project Unit under Project Nos. 05/2012-62, 05/2012-63, 05/2012-07 and 05/2012-08

The behaviour of satellite cells in response to exercise: what have we learned from human studies?

Understanding the complex role played by satellite cells in the adaptive response to exercise in human skeletal muscle has just begun. The development of reliable markers for the identification of satellite cell status (quiescence/activation/proliferation) is an important step towards the understanding of satellite cell behaviour in exercised human muscles. It is hypothesised currently that exercise in humans can induce (1) the activation of satellite cells without proliferation, (2) proliferation and withdrawal from differentiation, (3) proliferation and differentiation to provide myonuclei and (4) proliferation and differentiation to generate new muscle fibres or to repair segmental fibre injuries. In humans, the satellite cell pool can increase as early as 4 days following a single bout of exercise and is maintained at higher level following several weeks of training. Cessation of training is associated with a gradual reduction of the previously enhanced satellite cell pool. In the elderly, training counteracts the normal decline in satellite cell number seen with ageing. When the transcriptional activity of existing myonuclei reaches its maximum, daughter cells generated by satellite cell proliferation are involved in protein synthesis by enhancing the number of nuclear domains. Clearly, delineating the events and the mechanisms behind the activation of satellite cells both under physiological and pathological conditions in human skeletal muscles remains an important challenge

Formation of hydrogen bonding network of methane sulfonic acid at low degree of hydration (MSA)m·(H2O)n (m = 1–2 and n = 1–5)

Abstract This study employs ab initio calculations based on density functional theory (DFT) to investigate the structural properties, 1H-NMR spectra, and vibrational spectra of methane sulfonic acid (MSA) at low degree of hydration. The findings reveal that energetically stable structures are formed by small clusters consisting of one or two MSA molecules (m = 1 and 2) and one or two water molecules in (MSA)m·(H2O)n (m = 1–2 and n = 1–5).These stable structures arise from the formation of strong cyclic hydrogen bonds between the proton of the hydroxyl (OH) group in MSA and the water molecules. However, clusters containing three or more water molecules (n > 2) exhibit proton transfer from MSA to water, resulting in the formation of ion-pairs composed of CH3SO3 − and H3O+species. The measured 1H-NMR spectra demonstrate the presence of hydrogen-bonded interactions between MSA and water, with a single MSA molecule interacting with water molecules. This interaction model accurately represents the hydrogen bonding network, as supported by the agreement between the experimental and calculated NMR chemical shift results