Direct Quantification of Campylobacter jejuni in Chicken Fecal Samples Using Real-Time PCR: Evaluation of Six Rapid DNA Extraction Methods

Direct and accurate quantification of Campylobacter in poultry is crucial for the assessment of public health risks and the evaluation of the effectiveness of control measures against Campylobacter in poultry. The aim of this study was to assess several rapid DNA extraction methods for their effectiveness for the direct quantification (without enrichment) of Campylobacter jejuni in chicken fecal samples using real-time PCR. The presence of inhibitory substances in chicken fecal samples may reduce or even completely impede the PCR amplification process making quantification very difficult. Six rapid DNA extraction methods were compared based on their limit of detection, efficiency, reproducibility, and precision. Standard curves were designed for all the methods tested in order to assess their performance on the direct quantification of C. jejuni in chicken fecal samples. As a result of this study, the Easy-DNA (Invitrogen) method generated lower Ct values, the best amplification efficiency (AE?=?93.2 %) and good precision (R squared?=?0.996). The method NucleoSpin® Tissue was able to detect samples spiked with the lowest Campylobacter concentration level (10 CFU/ml) but the amplification efficiency was not optimal (AE?=?139.5 %). DNA extraction methods Easy-DNA Invitrogen, MiniMAG® and NucleoSpin® Tissue produced good real-time PCR reproducibility generating standard deviations from 0.3 to 0.8 between replicates.     

The problem of hot spots in microwave equipment used for preparatory techniques—Theory and practice

Electron microscopists who wants to use a microwave (MW) oven to stimulate preparatory processes are sooner or later confronted with the problem of hot spots. It soon becomes clear to the user of any MW oven that the energy distribution—thus the speed of absorbing energy, and hence warming up—varies topographically. The unaware can observe variations in results when the principles of topographic order are not followed meticulously. To understand the hot-spot phenomenon a certain theoretical knowledge is needed, as presented in this paper. In the 10 years that we have used MW ovens for our preparatory techniques we have learned how to solve the problem of hot spots. Thermographic paint can be applied to record energy distribution. In our studies, we have used a fiberoptic thermometer to follow precisely in time the temperature in the MW-exposed media, and these observations have provided us with the needed insight to obtain reproducible results. We argue that only when temperature curves are given by the authors can their recipes be used successfully in other laboratories.     

A new computational method for transient dynamics including the low‐ and the medium‐frequency ranges

This paper deals with a new computational method for transient dynamic analysis which enables one to cover both the low‐ and medium‐frequency ranges. This is a frequency approach in which the low‐frequency part is obtained through a classical technique while the medium‐frequency part is handled through the variational theory of complex rays (VTCR) initially introduced for vibrations. Preliminary examples are shown. Copyright © 2005 John Wiley & Sons, Ltd.     

Flame retardancy and thermal and mechanical performance of intercalated,layered double hydroxide composites of polyamide 11, aluminum phosphinate,and sulfamic acid

Sulfamic acid‐intercalated MgAl‐layered double hydroxide (SA‐LDH) was prepared and added with aluminum phosphinate (AlPi) into polyamide 11 (PA11). The results showed that AlPi/SA‐LDH made a positive contribution to both flame retardancy and thermostability, and the effect was demonstrated with the limiting oxygen index (LOI), vertical burning tests (UL‐94), cone calorimetry (CONE), and thermogravimetric analysis (TGA). The char morphologies were observed by SEM, and its chemical composition was investigated by Fourier transform infrared spectroscopy (FTIR). The decomposition mechanism was examined by TGA‐FTIR. The results showed that the LOI of PA11 was only 23.0 and cannot pass any UL‐94 rating. The addition of 20% AlPi increased the LOI to 31.5 and passed the UL‐94 V‐1 rating, and AlPi/SA‐LDH 15%/5% increased the LOI to 32.4 and also passed the UL‐94 V‐1 rating. The CONE results revealed that 20% of either AlPi or AlPi/SA‐LDH brought about a 30% decrease in the peak heat release rate (pHRR). The contribution of SA‐LDH to flame behavior was especially reflected in the postponement of pHRR. SEM showed that the char morphologies became denser after SA‐LDH incorporation. The improvement in thermal stability of the AlPi/SA‐LDH combination was documented by TGA in both N₂ and air atmospheres. The mechanical performance deterioration caused by AlPi was partly improved by SA‐LDH. The storage modulus (E′) below the T_g of AlPi/SA‐LDH 15%/5% was about 300 MPa higher than with 20% AlPi. This was attributed to a compatibility improvement. The interaction forces among PA11, AlPi, and SA‐LDH were probed by X‐ray photoelectron spectrometry. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43370.     

Combining NDT techniques for improved evaluation of concrete properties

Developing a strategy for the management and maintenance of the built heritage is a key challenge for research. In this context, a large experimental program was implemented to develop a methodology for non-destructive testing (NDT) of concrete structures based on the determination of: (a) the sensitivity of the NDT techniques, (b) the uncertainty of the NDT measurements, and (c) the optimal combination of NDT techniques to enhance the evaluation of concrete properties.This paper presents the strategy employed and the first results obtained from a comprehensive experimental database of NDT techniques. It also emphasizes how the variability of measurements can be taken into account and how statistical analyses can be used to evaluate the relevance of the available NDT techniques.     

Dietary patterns of adults living in Ouagadougou and their association with overweight

Background  

Urbanization in developing countries comes along with changes in food habits and living conditions and with an increase in overweight and associated health risks. The objective of the study was to describe dietary patterns of adults in Ouagadougou and to study their relationship with anthropometric status of the subjects.     

Modelling of the radiative properties of an opaque porous ceramic layer

Solid Oxide Fuel Cells (SOFCs) operate at temperatures above 1,100 K where radiation effects can be significant. Therefore, an accurate thermal model of an SOFC requires the inclusion of the contribution of thermal radiation. This implies that the thermal radiative properties of the oxide ceramics used in the design of SOFCs must be known. However, little information can be found in the literature concerning their operating temperatures. On the other hand, several types of ceramics with different chemical compositions and microstructures for designing efficient cells are now being tested. This is a situation where the use of a numerical tool making possible the prediction of the thermal radiative properties of SOFC materials, whatever their chemical composition and microstructure are, may be a decisive help. Using this method, first attempts to predict the radiative properties of a lanthanum nickelate porous layer deposited onto an yttria stabilized zirconium substrate can be reported.     

Influence of the carbon texture of platinum/carbon aerogel electrocatalysts on their behavior in a proton exchange membrane fuel cell cathode

Seven carbon aerogels (CAs) with different pore size distributions were synthesized and used as a catalyst support in proton exchange membrane fuel cell (PEMFC) cathodes. The cathodes were tested in 50 cm² membrane electrode assemblies. The results demonstrate that the CA texture significantly influences performance by impacting gas diffusion and proton transport. Also, the Nafion^® loading must be adapted to the CA texture, since its easier penetration into large pores favors their obstruction and results in higher proton resistance and mass-transport voltage losses. Under fixed experimental conditions (notably Nafion^®/carbon ratio = 1), the best CA support displays high specific surface area and pore volume, a majority of mesopores with a pore size distribution peak around 25–30 nm and with some macropores. The work confirms that the carbon support structure must be controlled to reduce mass-transport voltage losses. Doing so would lead to reduce PEMFC overall cost per kW.     

Wood shrinkage: influence of anatomy, cell wall architecture, chemical composition and cambial age

The influence of microfibril angle (MfA), density and chemical cell wall composition on shrinkage varied between the longitudinal and tangential directions as well as between wood types, namely compression wood (CW), mature wood (MW) and juvenile wood (JW). At the same MfA, CW exhibited a lower tangential shrinkage than JW, indicating the influence of the chemical composition on wood shrinkage. The chemical composition measured via FTIR micro-spectroscopy has been shown in conjunction with density to be an alternative to MfA data for shrinkage predictions. This was particularly true for wood of young cambial age for which the MfA did not correlate to shrinkage. The results indicate a possibility to reduce distortion of sawn timber by segregation using infrared (IR) and X-ray in-line measurements.     

Characterization of strain microgauges for the monitoring of the deformations of a medical needle during its insertion in human tissues

Further to the first fabrication of strain microgauges on cylindrical metal substrates (Yang et al. Microelectron Eng 97:285–288, 2012), that we cannot experiment because of problems of wire bonding, we have reviewed the bonding process. These microgauges enable the real-time measurement of the medical needle strain distribution from which its deflection status can be deduced. So this paper deals with the new bonding process of the microgauges and the detailed experimentations. These experimentations consist in constrain the needle and verify that we can measure the strain. They allow also the calculations and the comparison of the theoretical and experimental gauge factor. Finally we discuss about the improvement of the prototype in terms of optimization of the process. Finally some material questions must find solution.