Salmonella Dublin associated with abortion in dairy cattle in Algiers and comparison of different diagnostic methods

Background: In cattle, many serotypes of Salmonella enterica are responsible for a wide variety of clinical manifestations, which can cause considerable economic loss. Some serotypes can cause cows to abort sporadically, such as the Dublin serotype. This study was carried out on different cattle farms in the Algiers region to determine the prevalence of Salmonella Dublin using bacteriological and immunological methods.Methodology: The prevalence of Salmonella was determined by bacteriological analysis in accordance with the reference method AFNOR NF U 47-100 on faecal samples collected from 184 cattle belonging to 19 different farms, and serotyping for S. Dublin. Immunological analysis by enzyme-linked immunosorbent assay (ELISA) for S. Dublin was carried out on milk samples collected from 91 cattle. A survey of case (n=5) and control (n=14) farms for comparative analysis was performed to demonstrate a link between abortion in cows and prevalence of S. Dublin with both bacteriological and immunological methods. Sensitivity, specificity, Cohen Kappa coefficient, McNemar test odds ratios, and confidence intervals were calculated using Winepiscope 2.0 and StatA 9.1 software,and p<0.05 was considered as statistically significant.Results: The bacteriological results showed a prevalence of 7.6% (95%CI: 3-10), for Salmonella and serotyping revealed a prevalence for S. Dublin of 2.7%. The immunological analysis of milk by the ELISA technique revealed a prevalence of 13.2% (95%CI: 5-20) for S. Dublin. The comparative study between immunological results from milk and bacteriological results from faeces for detecting S. Dublin  showed poor agreement between the two tests (k=0.25), with enzyme immunoassay being significantly more sensitive than the bacteriological test (p<0.05). The results of the survey did not demonstrate a clear association between bacteriological detection of S. Dublin in faeces and abortion in cows (OR=8.66, 95%CI: 0.58-130.12). However, with the immunological analysis of milk for S. Dublin, there was a significant positive association (OR=62.33, 95%CI: 2.13-18.22) between a positive antibody response to S. Dublin in milk and the presence of abortions on the farm.Conclusion: In view of these results, we can conclude that Salmonella infections should systematically feature in the differential diagnosis of abortions in dairy cattle in Algeria. Keywords: S. Dublin, cattle, faeces, milk, abortion, immunology, bacteriology, Algier

Thermoelectric La-doped SrTiO3 epitaxial layers with single-crystal quality: from nanometer to micrometer and mosaicity effects

High-quality thermoelectric LaxSr1-xTiO3 (LSTO) layers (here with x = 0.2), with thicknesses ranging from 20 nm to 700 nm, have been epitaxially grown on SrTiO3(001) substrates by enhanced solid-source oxide molecular-beam epitaxy. All films are atomically flat (with rms roughness < 0.2 nm), with low mosaicity (<0.1{\deg}), and present very low electrical resistivity (<5 x 10-4 ohm.cm at room temperature), one order of magnitude lower than commercial Nb-doped SrTiO3 single-crystalline substrate. The conservation of transport properties within this thickness range has been confirmed by thermoelectric measurements where Seebeck coefficients of around -60 microV/K have been found for all films, accordingly. Finally, a correlation is given between the mosaicity and the (thermo)electric properties. These functional LSTO films can be integrated on Si in opto-microelectronic devices as transparent conductor, thermoelectric elements or in non-volatile memory structures

Characterization and Control of Supercapacitors Bank for Stand-Alone Photovoltaic Energy

AbstractIn this paper, a simple scheme of the supercapacitor based on (RC) circuit is modeled and characterized using experimental methods. Then, computer simulations and experimental results showed very good agreement which demonstrates the accuracy of the adopted model. An example of hybrid photovoltaic/supercapacitor stand-alone system is considered in this paper. Dynamic model of photovoltaic system component is developed and validated with experimental results. In addition, the maximum power point tracking (MPPT) control for photovoltaic and the supercapacitor state of charge (SOC) control are also addressed in this work. Based on the dynamic component models, a simulation model for the considered hybrid energy system has been developed using MATLAB/Simulink. The simulation results show the primary role of the supercapacitor when the load changes rapidly

Implementation of fuel cell and photovoltaic panels based DC micro grid prototype for electric vehicles charging station

Today, electric vehicle (EV) appears as an evident solution for the future automotive market. The introduction of EV will lead to the reduction of greenhouse gas emissions and decrease the travelling cost. However, electric vehicle is truly an ecological solution only if the production of electricity necessary for its operation is produced from sustainable energy sources. In this paper, an Electric Vehicle Charging Station (EVCS) through sustainable energy sources via a DC micro-grid system has been proposed. The proposed system includes a fuel cell (FC), photovoltaic (PV) panels, storage battery and possibility of a connection to the grid. In this work a low power prototype of a micro-grid based EVCS has been first validated using a numerical simulation under Matlab/Simulink using variable irradiance and number of recharging vehicles. In the second part of this paper, an EVCS prototype has been realized in the laboratory. The tests are realized using an emulator of the PEM fuel cell with the concept of the hardware-in-the-loop (HIL). The objective of this emulation is to evaluate the performances of the whole system without the need for a real fuel cell. The whole system is implemented on the dSPACE 1103 platform and the results of the tests are discussed.N/

STUDY OF SALMONELLA SPP. CARRIAGE IN FECAL OF BOVINE ORIGIN IN THE WILAYA OF TIZI OUZOU (ALGERIA)

The objective of this study was to evaluate the importance of the reservoir of Salmonella spp. in dairy cattle through the study of asymptomatic carriage in feces in some municipalities of the Wilaya of Tizi Ouzou. 548 fecal samples from 65 farms were carried out, and the ISO 6579 method was used for the analysis of the samples. The results showed that 13.48% of the farms and 2.18% of the samples were positive for the search of Salmonella spp. Most of the strains (75%) were resistant to a maximum of two antibiotics and 25% of the strains were multidrug resistant. No relationship between practices observed in the field and the excretion of Salmonella spp. could be demonstrated

Simulation and experimental investigation into a photovoltaic and fuel cell hybrid integration power system for a typical small house application

The paper addresses the simulation of a novel real-time implementation of a photovoltaic (PV) and fuel cell (FC) hybrid integration power system. The hybrid system has the potential of reducing the dependency on batteries, leading to reduced cost and increased life span of the whole system using the Proton Exchange Membrane (PEM) fuel cell. The interface structure of the hybrid system has been explored incorporating the Maximum Power Point Technique (MPPT) for maximum power extraction. The simulation of the hybrid system including fuel cell, PhotoVoltaic panels (PVs) and battery has been carried out using SimPowerSystems. An innovative Real Time Interface (RTI) approach using the concept of the Hardware-In-the-Loop (HIL) has been presented for a fast dynamic response of a closed loop control of the hybrid system. The corroboration of the hybrid system is validated experimentally, using a real photovoltaic panel connected to a PEM fuel cell emulator and battery. The PVs are controlled by the perturbation and observation Maximum Power point (MPP) technique and the PEM fuel cell is controlled through a boost DC-DC converter using current mode control. The whole system is implemented on the dSPACE 1103 platform for real-time interface and control strategies. The overall behavior of the hybrid system has been critically analyzed and corroboration of the simulated and experimental results have been presented.N/

Impact and efficiency of GH10 and GH11 thermostable endoxylanases on wheat bran and alkali-extractable arabinoxylans

International audienc

Transient thermal conductivity in PECVD SiN x at high temperature: the thermal signature of an on-going irreversible modification

International audiencePECVD amorphous silicon nitride (a-SiN x) films are largely used into the dielectric stacks of integrated circuits, as passivation or capping layers, and are today an important alternative to silicon for integrated nonlinear optical applications, such as waveguides. In such applications, a-SiN x presents also the advantage of having a very low thermal conductivity, about 0.7 W/m K at room temperature, which is of relevance, as such films contribute to the thermal balance of the devices, and thus play a role in solving the thermal management problem in microelectronics. The deposition parameters, and more specificall