Application of avidin-biotin technology and adsorptive transfer stripping square-wave voltammetry for detection of DNA hybridization and avidin in transgenic avidin maize

The proteins streptavidin and avidin were electrochemically detected in solution by adsorptive transfer stripping square wave voltammetry (AdTS SWV) at a carbon paste electrode (CPE). AdTS SWV was used to quantify biotinylated oligonucleotides, DNA hybridizations, and avidin in extracts of transgenic avidin maize. The detection limits of denatured and native streptavidin were 6 pM and 120 nM, respectively. The results demonstrated that streptavidin/avidin AdTS SWV is a sensitive and specific method for quantifying DNA and proteins in biological samples such as foods and tissue extracts, including genetically modified crops (avidin maize) and other plants in neighboring fields.     

Sensing methodology for in vivo stability evaluation of total hip and knee arthroplasty

This paper describes an implantable, remotely interrogated system for the in vivo measurement of both micromotion and migration in applications such as total hip arthroplasty (THA) and total knee arthroplasty (TKA). These metrics are the primary indicators of post-operative implant stability and their easy availability represents an important advance in the ability of clinicians to assess the long-term stability of the implants and also to plan and optimise patients’ rehabilitation protocols. The system is based on a modified form of differential variable reluctance transducer (DVRT) whose null-point is set automatically by means of a self-calibration algorithm. The self-calibration process not only allows the measuring bridge to work at maximum accuracy (i.e. for micromotion measurements) but also automatically records gross changes in position (migration). Simulations and preliminary measurements show that the calibration algorithm works correctly in spite of component tolerances and initial set up errors, and that the device can measure micromotion with an amplitude as low as 1 μm with a gross displacement (migration) in the range 0 to ±4 mm.     

Computer-tailored smoking cessation intervention in a general population setting in Germany: outcome of a randomized controlled trial.

This study reports the outcome of a randomized controlled trial testing a computer-tailored smoking cessation intervention based on the transtheoretical model in a general population setting in Germany. Participants of the smoking intervention study were recruited from an existing general population health examination survey in a university hospital. The sample consisted of 611 current and former smokers at baseline, and of 485 participants in the core group of baseline daily cigarette smokers. Follow-ups were conducted 6, 12, 18, and 24 months after baseline. The intervention was designed for both current and former smokers, involved up to three individualized feedback letters, and was created using expert-system technology. Based on 7-day point-prevalence abstinence and 6-month prolonged abstinence as the outcome measures, the study identified no significant differences between the intervention and control groups. Modeling the full longitudinal data in generalized estimation equation analyses, using different nonresponse procedures, and adjusting for covariates did not alter the results. We conclude that the computer-tailored transtheoretical model-based smoking cessation intervention, as delivered in this study and in this special setting, was ineffective.     

Biogenic amines and their producers in Akawi white cheese

The aim of this work was to study the biogenic amine content of brine‐ripened cheeses after one year of storage and then to investigate possible contaminating micro‐organisms with decarboxylase activity. The biogenic amine production of isolates was tested in vitro. The most frequent biogenic amines were putrescine, histamine and tyramine. The biogenic amine content detected in one cheese sample was above 120 mg/kg; this can be considered toxicologically relevant. Decarboxylase activity was found for 33 contaminating micro‐organisms. Isolates belonging to Bacillus licheniformis, Debaryomyces hansenii, Staphylococcus equorum and Serratia marcescens produced significant amounts of putrescine and cadaverine.     

Characterisation and modelling of the elastic properties of poly(lactic acid) nanofibre scaffolds

The aim of this study is to predict the elastic response of poly(lactic acid) (PLA) electrospun nanofibre scaffolds through mathematical models based on homogenisation and the differential replacement method (DRM). These models principally seek to determine and analyse the effects of the internal morphology of the nanofibres on the effective Young’s modulus of polymer nanofibre scaffolds. The microstructure of the nanofibres was first characterised by SEM, XRD, DSC, AFM, and TEM techniques. From this characterisation, strong evidence of a hierarchical core–shell structure was found. With the experimental data, it was possible to design and validate better models than those currently used. In addition, the effects of the electrospinning parameters, such as take-up velocity and thermal treatment, were analysed and correlated with the morphology and the elastic properties of the nanofibres and their scaffolds. To validate the models’ results, we conducted a series of uniaxial tensile tests on the PLA nanofibre scaffolds. Using the data from the nanofibre measurements, the homogenisation approximations and the model based on the DRM predicted an effective Young’s modulus of 667 and 835 MPa, respectively. The predicted data were in excellent agreement with the experimental results (685–880 MPa). These models will be useful in understanding and evaluating the structure–property relationships of oriented nanofibre scaffolds for medical or biological applications.     

Protein and glycerol contents affect physico-chemical properties of soy protein isolate-based edible films

This study was conducted to determine the effect of both soy protein and glycerol contents on physico-chemical properties of soy protein isolate-based edible (SPI) films. The aim of this study was to better understand the influence of SPI and GLY contents on the behavior of the physico-chemical properties of soy protein isolate-based films. Films were casted from heated (70 °C for 20 min) alkaline (pH 10) aqueous solutions of SPI at 6, 7, 8, and 9 (w/w %), glycerol (50%, w/w, of SPI) and SPI at 7 (w/w %), glycerol (40, 60, 70 %, w/w of SPI). Water vapor permeability (WVP), was measured at 25 °C and for four different relative humidities (30–100%, 30–84%, 30–75%, 30–53%). Surface properties and differential scanning calorimetry were also measured. Varying the proportion of SPI and GLY had an effect on water vapor permeability, wetting and thermal properties of SPI films. A synergistic effect of glycerol and protein was observed on the water vapor permeability. Glycerol and RH gradient strongly enhance the moisture absorption rates and permeability of SPI based films. SPI content weakly increases the WVP and does not modify the surface properties. The temperature of denaturation of soy protein decreases glycerol content except for the higher concentration whereas it increases with protein ratio.Industrial relevanceThis topic of research aims to control mass transfers within composite foods or betweenfoods and surrounding media (for instance the headspace in packagings). The targeted applications from this work deals with the food product coating or the coating of paper-based packaging for limiting both the loss of water and flavors by cheese based products. This will allow to maintain the weight of the cheese during “ripening” and commercialization, and also to prevent (off-) flavour dissemination from very odorant cheese as produced in France and Poland.     

The effect of washing on physicochemical changes in packaged, sliced green peppers

Whole green bell peppers (Capsicum annuum L.) were obtained through a local fresh‐cut company. They were washed in a 100 ppm chlorine solution, dried and then sliced into 0.5‐cm wide strips. A bulk sample of slices was divided into four treatments: (1) no wash, (2) one wash in fresh distilled water, (3) two sequential washes in fresh distilled water, and (4) three sequential washes in fresh distilled water. Retention of firmness of the pepper slices during storage at 7 °C improved with the number of washes after cutting. The modification of package atmosphere was less in all wash treatments than in the ‘no wash’ control. The sliced tissues of ‘no wash’ controls had higher levels of acetaldehyde and ethyl acetate. Analysis of the wash water revealed that sequential washes with water removed incremental amounts of acetaldehyde and soluble phenols from the cut surfaces of the tissue. These results show that washing has a dramatic effect on physicochemical measures of quality in green pepper slices, and it is likely that this effect is mediated by the removal of stress‐related compounds produced during the cutting operation. While acetaldehyde and total phenolics were the two stress‐related compounds measured in the wash water, it may be that other compounds removed in the wash water could have contributed to the beneficial effects on quality reported in this study.     

Structural Basis for Antimicrobial Activity of Lasiocepsin

Lasiocepsin is a unique 27‐residue antimicrobial peptide, isolated from Lasioglossum laticeps (wild bee) venom, with substantial antibacterial and antifungal activity. It adopts a welldefined structure consisting of two α‐helices linked by a structured loop. Its basic residues form two distinct positively charged regions on the surface whereas aliphatic side chains contribute to solvent‐accessible hydrophobic areas, thus emphasising the amphipathic character of the molecule. Lasiocepsin structurally belongs to the ShK family and shows a strong preference for anionic phospholipids; this is further augmented by increasing concentrations of cardiolipin, such as those found at the poles of bacterial cells. The membrane‐permeabilising activity of the peptide is not limited to outer membranes of Gram‐negative bacteria. The peptide interacts with phospholipids initially through its N terminus, and its degree of penetration is strongly dependent on the presence of cardiolipin.     

Two analytical models for the study of periodic fibrous elastic composite with different unit cells

In this work, the effective elastic moduli of two-phase fibrous periodic composites are obtained by means of the Asymptotic Homogenization Method (AHM) and eigenfunction expansion-variational method (EEVM), for different types of parallelogram cells. The constituents exhibit transversely isotropic properties. A doubly periodic parallelogram array of cylindrical inclusions under longitudinal shear is considered. The behavior of the shear elastic coefficient for different geometry arrays of the cell related to the angle of the fibers is studied. Some numerical examples and comparisons with other theoretical results demonstrate that both methods (AHM and EEVM) are efficients for the analysis of composites with presence of rhombic cell. The effect of the configuration of the cells on the shear effective property is observed.