Skeletal Muscle Proteomic Profile Revealed Gender-Related Metabolic Responses in a Diet-Induced Obesity Animal Model

Obesity is a chronic, complex pathology associated with a risk of developing secondary pathologies, including cardiovascular diseases, cancer, type 2 diabetes (T2DM) and musculoskeletal disorders. Since skeletal muscle accounts for more than 70% of total glucose disposal, metabolic alterations are strictly associated with the onset of insulin resistance and T2DM. The present study relies on the proteomic analysis of gastrocnemius muscle from 15 male and 15 female C56BL/J mice fed for 14 weeks with standard, 45% or 60% high-fat diets (HFD) adopting a label-free LC–MS/MS approach followed by bioinformatic pathway analysis. Results indicate changes in males due to HFD, with increased muscular stiffness (Col1a1, Col1a2, Actb), fiber-type switch from slow/oxidative to fast/glycolytic (decreased Myh7, Myl2, Myl3 and increased Myh2, Mylpf, Mybpc2, Myl1), increased oxidative stress and mitochondrial dysfunction (decreased respiratory chain complex I and V and increased complex III subunits). At variance, females show few alterations and activation of compensatory mechanisms to counteract the increase of fatty acids. Bioinformatics analysis allows identifying upstream molecules involved in regulating pathways identified at variance in our analysis (Ppargc1a, Pparg, Cpt1b, Clpp, Tp53, Kdm5a, Hif1a). These findings underline the presence of a gender-specific response to be considered when approaching obesity and related comorbidities.     

Electrical properties of molybdenum disulfide MoS2. Experimental study and density functional calculation results

Molybdenum disulfide is a very interesting material with numerous applications. However, to our knowledge, very few experimental works involving electrical measurements have been performed with this material up to now. This paper is devoted to the characterization of conduction mechanisms in thin layers and pressed pellets. The electronic structure related to the lubricating properties and the activation energy are determined using theoretical calculations (density functional theory) and experimental methods. A good agreement is found between the theoretical predictions and the experimental results. D.c. and a.c. conductivities are measured in the frequency range 10–10⁷ Hz. The electronic transport mechanism is discussed in terms of Mott hopping in samples. The a.c. conductivity at high frequencies can be expressed by the formula σ_ac(ω) = Aω¹¹, where the slope n is close to 0.8.     

A green scheduling with adaptive spatial division multiple access grouping for multi‐user coordinated multi‐point networks

Multi‐User Coordinated Multi‐Point (MU‐CoMP), which couples CoMP with Multi User‐Multiple Input Multiple Output (MU‐MIMO), appears as a promising solution to enhance the Long Term Evolution‐Advanced (LTE‐A) system performance. However, some challenging issues in MU‐CoMP networks require more investigation. First, the set of users transmitting under CoMP mode should be properly identified. Secondly, time‐frequency resource should be efficiently partitioned between CoMP and non‐CoMP users in order to improve the system radio capacity. Thirdly, a fair and green scheduler is much needed for a more energy efficient system. This paper deals with these three issues. We propose an adaptive transmission mode selection according to the total load in the cluster and to users' quality of service. The adequate size of the Spatial Division Multiple Access users' groups is also analyzed. We finally propose a new scheduling algorithm to further enhance the radio capacity and the energy consumption in the cluster. Simulations results showed that significant improvements are obtained in terms of total system throughput and outage probability in the cluster with our proposed scheme. Moreover, energy efficiency has increased by four times with our proposed scheduling algorithm as compared to commonly used schedulers. Copyright © 2015 John Wiley & Sons, Ltd.     

Comparison between three years of daily global radiation measurements in three Tunisian sites against assessments from METEOSAT Wefax images

GISTEL is a satellitary methodology based on a simple physical model with two components. It is used to estimate global solar irradiance from METEOSAT data. The treated images in the present sequel are of Wefax type of the ‘visible channel’ of METEOSAT.Our method has been applied in Tunisia. The estimated daily solar global radiation is compared to the measured values performed in three meteorological stations in the North of Tunisia during three successive years. The obtained results have shown that the accuracy level of our method is acceptable for energy applications. Our results show the convenience of GISTEL method to METEOSAT-Wefax images. In general, the relative error does not exceed 20% of the global irradiation. The recorded errors between estimated and measured values are, in some cases, linked to the model's parameters. They may also arise from the geographical situation of the site, the satellitary data or from the earth-based solar irradiation.     

Use of HR Meteosat images for the mapping of global solar irradiation in Tunisia: preliminary results and comparison with Wefax images

The evaluation of the incident solar energy on a given site becomes at the present time, one of the needs of the users and the manufacturers of energetic solar systems. For this purpose, we have developed, in collaboration with the Energy Climate Laboratory of Avignon University (France), an assessment method (GISTEL) of solar irradiation using Meteosat satellite images.We have shown in previous papers (Ben Djemaâ A, Delorme C. Solar Energy 48(5) 1992 325; Chaâbane M, Ben Djemaâ A, Kossentini A. Solar Energy 57(6) 1996 449) the simplicity and efficiency of the GISTEL method to estimate global solar irradiation and its convenience compared with B2 and Wefax images.Herein we describe briefly our method and present the preliminary results obtained from a series of high resolution (HR) Meteosat images. The results are compared with values obtained at eight Tunisian meteorological stations and are then compared with the results obtained using Wefax images. A statistical study of the errors between estimated and measured values is presented and analysed.We also show the efficiency of the map-form of solar energy data for Tunisian territory and its potential for future studies. For Tunisia and African countries, these images present the best means for solar studies since they cover the quasi-totality of the African continent with a good temporal and spatial resolution.     

Electrical properties of ITO/benzylated cyclodextrins (β-CDs (Bz))/Al diode structures

Abstract

Investigations of the electrical characteristics of benzylated cyclodextrins (β-CDs (Bz)) diodes are reported. We present current–voltage characteristics and impedance spectroscopy measurements performed on partially benzylated cyclodextrins β-CDs (Bz) thin films in sandwich structures ITO/b-CDs (Bz)/Al. The static electrical characterizations show a space charge limited conduction (SCLC) and a conductivity with power low frequency behavior characteristic of a hopping transport in disordered materials. The impedance spectra can be discussed in terms of an equivalent circuit model designed as a parallel resistor R_p and capacitor C_p network in series with resistor R_s. We extract numerical values of these parameters by fitting experimental data. Their evolution with bias voltages has shown that the SCLC mechanism is characterized by an exponential trap distribution. We estimated from the capacitance voltage characteristic an acceptor concentration of about 10¹¹ cm^?3 due to trap states.     

Modeling and control of photovoltaic and fuel cell based alternative power systems

Photovoltaic (PV) systems and fuel cells (FCs) represent interesting solutions as being alternative power sources with high performance and low emission. This work presents a modeling and control study of two power generators; photovoltaic array and fuel cell based systems. An MPPT approach to optimize the PV system performances is proposed. The PV system consists of a PV array connected to a DC-DC buck converter and a resistive load. A maximum power point tracker controller is required to extract the maximum generated power. Based on Incremental Conductance (INC) principle, the idea of the proposed control is to use a Fuzzy Logic Controller (FLC) that allows the choice of the duty cycle step size which is used to be fixed in conventional MPPT algorithms. The variable step is computed according to the value of the PV power-voltage characteristic slope. The second working system comprises a controlled DC-DC converter fed by a proton exchange membrane fuel cell (PEMFC) and supplies a DC bus. The mathematical model of the PEMFC system is given. The converter duty cycle is adjusted in order to regulate the DC bus voltage. Obtained simulation results validate the control algorithms for both of studied power systems.     

Nanostructural, optical and electrical properties of vacuum evaporated films of an azo-calix[4]arene derivative

The nanomorphology, optical and electrical properties of vacuum-deposited azo-calix[4]arene thin films have been investigated. The nanostructured films exhibit absorption spectra with a resolved electronic structure in the UV-vis and a blue photoluminescence emission at about 430 nm independent of the excitation wavelength. The current-voltage (I-V) characteristics of ITO/azo-calix[4]arene/Au devices have been studied. The I-V dependence follows a power law, I ∝ V^m, which is typical of a space-charge-limited current. Moreover, from the I-V measurements, we have estimated the effective hole mobility of ∼7.5 × 10⁻⁶ cm²/V s in the vacuum-deposited azo-calix[4]arene thin films. Using impedance spectroscopy over a broad frequency range, i.e. 100 Hz to 10 MHz, it is found that the ac behavior of an ITO/azo-calix[4]arene/Au device shows several features, described by the simple RC circuit representing an undepleted bulk region. Values of the electrical circuit parameters deduced from fitting experimental data to the model have given a dielectric relaxation time in the millisecond range.