Incidence of Listeria spp. in fish and environment of fish markets in Northern Greece

The incidence of Listeria spp. in the salt-water edible fish and in the environment of fish markets in Thessaloniki, Northern Greece was studied. One hundred and twenty raw/fresh fish bought at the fish markets of Thessaloniki (Northern Greece), were sampled and tested for presence of Listeria species using a two step enrichment procedure, followed by plating on two selective agars and subsequent biochemical identification of the isolates. Five fish samples were positive for Listeria spp. and in only one sample L. monocytogenes was detected. Also, 100 samples of knives, hands, boxes etc were sampled and 18 samples were positive for Listeria spp. and five for L. monocytogenes. L. innocua was more common being detected in four fish samples and 13 environmental samples. L. seeligeri was detected only in one environmental sample. Our findings indicate that only a few fish were contaminated with Listeria spp., while the level of contamination of the environment of fish markets was higher.     

A mineralogical perspective on the apatite in bone

A crystalline solid that is a special form of the mineral apatite dominates the composite material bone. A mineral represents the intimate linkage of a three-dimensional atomic structure with a chemical composition, each of which can vary slightly, but not independently. The specific compositional–structural linkage of a mineral influences its chemical and physical properties, such as solubility, density, hardness, and growth morphology. In this paper, we show how a mineralogic approach to bone can provide insights into the resorption–precipitation processes of bone development, the exceedingly small size of bone crystallites, and the body's ability to (bio)chemically control the properties of bone. We also discuss why the apatite phase in bone should not be called hydroxylapatite, as well as the limitations to the use of the stoichiometric mineral hydroxylapatite as a mineral model for the inorganic phase in bone. This mineralogic approach can aid in the development of functionally specific biomaterials.     

Ultimate strength analysis of structural components using the continuum damage mechanics approach

In this study, an analytical model is developed to include the effect of material fracture on the overall behavior of a structure. The continuum damage mechanics approach is used to describe the continuous deterioration of the material stiffness that leads to total failure. The damage evolution is assumed to be anisotropic and the effect of the triaxiality of stress on the fracture criterion is included in the analysis. The above modifications were applied to an existing finite element program which is capable of including both geometric and material nonlinearities in the analysis. The program was used to analyze a welded tubular connection (T-joint). This joint was chosen because fracture was shown experimentally to control its ultimate behavior. Solid finite elements were used to model the chord and the branch in the intersection region, wedge elements were used for the weld profile, and the rest of the geometry was modeled using shell elements. The joint was subjected to an increasing amount of displacement at the far end of the branch. The loading was continued until total failure. During this process, the evolution of the damage and its propagation were monitored. Divergence of the solution was obtained at a failure load of 42.4 kips compared to 44.0 kips obtained experimentally. In addition, the failure mode of the joint predicted by the analysis was identical to that observed experimentally.     

Fractional alpha stable network traffic model and its application in QoS routing

It is not a simple and trivial work to set up an appropriate network traffic model. A fractional Alpha model is proposed in this paper and two proofs based on flow and session level, respectively, are given. Based on this model, the lower bound for the residual of the queueing distribution is deduced. Comparing the residual distribution function (RDF) based on our model with it based on other models, we find our formula matches the real RDF better. Based on this formula, we can predict the need for forwarding performance. Then a novel QoS routing algorithm based on this prediction is proposed. Last we demonstrate a simple example to denote how our algorithm can effectively improve the utility of bandwidth and amount of traffic and guarantee QoS.     

Integrated development of CFRP structures for a topless high performance vehicle

When modern saloon cars are re-engineered as convertibles (or roadsters) it is typical for them to lose 50% or more of the body’s torsional rigidity. Consequently the vehicles rarely handle quite as crisply, nor do they ride as well as the coupes from which they derived. This paper highlights the fundamental contributions of advanced composites in achieving the desired value of handling of the Murcièlago Roadster without penalizing the overall weight of the vehicle. To compensate for the absence of the roof structure, the vehicle was strongly redesigned by introducing new structural members and reinforcing existing critical components. A new all-carbon/epoxy composite sub-frame, which spans the entire engine bay, is comprised of elliptical tubular members, and it is the first of its kind in a production vehicle. Engineering of the sub-frame, from preliminary design to manufacturing decisions, is the focus of this paper, and is achieved through a Building Block approach that sets the program within the Integrated Product Development (IPD) strategy that the Advanced Composites Division of Automobili Lamborghini S.p.A. employs for its technology demonstrators. The strategy consists in a concurrent analytical and experimental development of the product, from the initial conceptual design and coupon testing, through the stages of element and subcomponent engineering, to final component manufacturing.     

Matrix assisted pulsed laser evaporation of biomaterial thin films

In this paper, processing of biomaterial thin films using a novel physical vapor deposition process known as matrix assisted pulsed laser evaporation (MAPLE) is reviewed. The matrix assisted pulsed laser evaporation process provides excellent control over several film parameters, including thickness, roughness, homogeneity, and reliability. Deposition of dexamethasone thin films, poly (d, l) lactic acid/dexamethasone bilayer thin films, and chitosan thin films is reviewed. The results highlight the expanding role of matrix assisted pulsed laser evaporation process in biomaterials, drug delivery, and tissue engineering.