Combined use of bacteriocin‐producing strains to control Listeria monocytogenes regrowth in raw pork meat

Avoiding the presence of Listeria in meat and dairy products is a major challenge for the food industry. In this work, a Lactobacillus curvatus strain producing the bacteriocin sakacin P and a Pediococcus acidilactici strain producing another bacteriocin, pediocin AcH, were used as starter cultures under laboratory conditions in a Listeria‐seeded raw‐pork‐meat matrix, which was then stored for 6 weeks at 4 °C. At 1 week intervals during the storage period, the antilisterial activity was evaluated. When either strain was added alone, the Listeria monocytogenes cfu count initially dropped from 10² cfu g^?1 to an undetectable level by the end of week 1 or 2, but this was followed by a rebound (regrowth) 1 week later. When both strains were added together to the meat matrix, rebound was delayed, Listeria remaining undetected from the end of week 1 to the end of week 5. A rebound was observed 6 weeks post‐inoculation, but fewer than 10 cfu g^?1 were counted. The use of more than one bacteriocin‐producing strain may thus overcome some of the problems limiting the effectiveness of bacteriocins in food systems.     

Visualizing and exploring profiles with calling context ring charts

Calling context profiling is an important technique for analyzing the performance of object‐oriented software with complex inter‐procedural control flow. The Calling Context Tree (CCT) is a common data structure that stores dynamic metrics, such as CPU time, separately for each calling context. As CCTs may comprise millions of nodes, there is a need for a condensed visualization that eases the localization of performance bottlenecks. In this article, we discuss Calling Context Ring Charts (CCRCs), a compact visualization for CCTs, where callee methods are represented in ring segments surrounding the caller's ring segment. In order to reveal hot methods, their callers, and callees, the ring segments can be sized according to a chosen dynamic metric. We describe two case studies where CCRCs help us to detect and fix performance problems in applications. A performance evaluation also confirms that our implementation can efficiently handle large CCTs. Copyright © 2010 John Wiley & Sons, Ltd.     

Evaluation of Ba2(In0.8Ti0.2)2O5.2−n(OH)2n as a potential electrolyte material for proton-conducting solid oxide fuel cell

Electrochemical measurements of fuel cells based on proton conductor electrolyte Ba₂(In_0.8Ti_0.2)₂O_5.2−n(OH)_2n and prepared through a tape casting process and a co-pressing of anode-composite powder and electrolyte tape were performed at 500 °C under wet H₂. The varying parameter between the prepared cells was the thickness of the electrolyte that can be controlled during the tape casting process. The maximum power density was obtained for the cell with the thinnest electrolyte (35 μm) and was about 22 mW cm⁻² with an ohmic resistance about 2 Ω cm² at 500 °C.     

In situ optical spectroscopy during deposition of Ag:Si3N4 nanocomposite films by magnetron sputtering

In situ and real time surface differential reflectance (SDR) spectroscopy is employed to study the growth of metallic Ag and/or dielectric Si₃N₄ films during deposition by magnetron sputtering. The measurements during Si₃N₄ sputtering allow determining both the refractive index and the deposition rate. During Ag sputtering, the SDR presents a maximum in the visible range, typical of a surface plasmon resonance (SPR) indicating the 3D growth of silver nanoclusters. After a certain deposition thickness, the SDR change corresponds to a continuous layer growth and allows determining the Ag deposition rate. During Ag/Si₃N₄ alternate deposition, the SDR spectroscopy enables to follow the SPR modifications (position, amplitude and width) not only during the formation of the Ag nanoclusters but also during their capping by a Si₃N₄ matrix and during intermediate steps (holding time after the silver sputtering, Si₃N₄ target ignition and pre-sputtering before the Si₃N₄ deposition) where significant changes are detected. It suggests possible nanocluster reshaping or physicochemical processes occurring at the nanocluster interface during the different steps.     

Unit Completion for a Computer-aided Translation Typing System

This work is in the context of, a system thatwatches over the users as they type a translation andrepeatedly suggests completions for the text already entered.The users may either accept, modify, or ignore these suggestions. Wedescribe the design, implementation, and performance of aprototype which suggests completions of units of texts that arelonger than one word.     

A GRASP×ELS for the vehicle routing problem with basic three-dimensional loading constraints

This paper addresses an extension of the capacitated vehicle routing problem where the client demand consists of three-dimensional weighted items (3L-CVRP). The objective is to design a set of trips for a homogeneous fleet of vehicles based at a depot node which minimizes the total transportation cost. Items in each vehicle trip must satisfy the three-dimensional orthogonal packing constraints. This problem is strongly connected to real-life transportation systems where the packing of items to be delivered by each vehicle can have a significant impact on the routes. We propose a new way to solve the packing sub-problem. It consists of a two-step procedure in which the z-constraints are first relaxed to get a (x,y) positioning of the items. Then, a compatible z-coordinate is computed to get a packing solution. Items can be rotated but additional constraints such as item fragility, support and LIFO are not considered. This method is included in a GRASP×ELS hybrid algorithm dedicated to the computation of VRP routes. The route optimization alternates between two search spaces: the space of VRP routes and the space of giant trips. The projection from one to the other is done by dedicated procedures (namely the Split and the concatenation algorithms). Moreover, a Local Search is defined on each search space. Furthermore, hash tables are used to store the result of the packing checks and thus save a substantial amount of CPU time. The effectiveness of our approach is illustrated by computational experiments on 3L-CVRP instances from the literature. A new set of realistic instances based on the 96 French districts are also proposed. They range from 19 nodes for the small instances to 255 nodes for the large instances and they can be stated as realistic since they are based on true travel distances in kilometers between French cities. The impact of the hash tables is illustrated as well.     

Net Shape Fins for Compact Heat Exchanger Produced by Cold Spray

This work explores the manufacturability of pyramidal fin arrays produced using the cold spray process. Near-net shaped pyramidal fin arrays of various sizes and fin densities were manufactured using masks made of commercially available steel wire mesh. The feedstock powders used to produce the fins are characterized using scanning electron microscopy. Obstruction of the masks was investigated. The standoff distances between the substrate, mesh, and nozzle were empirically determined. Fin array characterization was performed using digital microscopy. The fin arrays’ heat transfer performance was assessed experimentally for a range of Reynolds number relevant to the application sought. The fins produced using the cold spray process outperform traditional straight (rectangular) fins at the same fin density and it is hypothesized that this is due to increased fluid mixing and turbulence.     

Effects of carbon nanotubes and their state of dispersion on the anionic polymerization of ϵ‐caprolactam: 1. Calorimetry

This work reports, for the first time, on the effect of carbon nanotubes (CNT) on the kinetics of the activated polymerization of lactams. Differential scanning calorimetry (DSC) was chosen to study the kinetics of the activated anionic polymerization of ε‐caprolactam in the presence of multiwalled carbon nanotubes (MWCNT). A statistical test was carried out to confirm the validity of the experimental approach. The presence of the MWCNT slowed down the polymerization rate. This inhibiting effect depended not only on the MWCNT content but also on its state of dispersion in the polymerizing system. An autocatalytic model coupled with an evolutionary algorithm showed that the MWCNT content had an effect on the autocatalysis while its state of dispersion had an effect on the apparent polymerization kinetic constant. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers     

A Neo-institutionalist Model of the Diffusion of IFRS Accounting Standards

The purpose of this study is to prepare a diffusion model of the new international accounting standards known as the international financial reporting standards (IFRS). This model fits within the neo-institutional conceptual framework; more specifically, we used the DiMaggio/Powell analytical grid. Our desire to prepare this model was born from the observation that the analytical framework that is generally used to study the adoption of these new standards is the neo-institutional framework and that the principal methodologies implemented are qualitative. The question addressed in this study regards the forces leading an agent—in this case, an organisation providing standards for accounting—to adopt, at a given moment, these new standards. Existing studies, as interesting as they might be, are devoted to the question of adoption and leave aside the question of diffusion. In other words, the evolution of the system as a whole in time is ignored. Constructing a model appeared to us to be a way to move beyond these limitations. This model allows us to formalise the forces at work in the DiMaggio/Powell representation and to simulate the diffusion processes of the IFRS. To this end, we implement a multi-agent simulation. The various simulation scenarios are then compared to the observed diffusion of the IFRS.