Methicillin-resistant Staphylococcus aureus (MRSA) in foods of animal origin product in Italy

Methicillin-resistant Staphylococcus aureus (MRSA) strains are a global health concern. The present study regarded 160 S. aureus strains that had been isolated from 1634 foodstuff samples of animal origin in a previous survey conducted in Italy during 2003-2005. The strains were characterized by detecting the mecA gene, the production of type A to D staphylococcal enterotoxins (SEs), and studying their resistance properties against several antibiotics; their ecological origin was determined by biotyping. Of the 160 analyzed S. aureus strains six (3.75%) were mecA positive and derived from six different samples; four isolates were from bovine milk and two from dairy products (pecorino cheese and mozzarella cheese). Two strains isolated from milk belonged to the non-host-specific biovar while the others to the ovine biovar. The strain isolated from mozzarella cheese belonged to the non-host-specific biovar and the strain isolated from pecorino cheese to the ovine biovar. All the MRSA strains isolated were enterotoxigenic; two strains synthesized SEA/SED two SED and one SEC. All the strains showed resistance to at least one of the antibiotics tested but none was resistant to glycopeptides.     

SPIRAL: A novel biologically-inspired algorithm for gas/odor source localization in an indoor environment with no strong airflow

This work describes the design and experimental results of an algorithm, designed to localize a gas source in an indoor environment with no strong airflow by using an autonomous agent. This condition exacerbates the patchiness and intermittency of odor distribution, typical of turbulent flows in the presence of strong mean flows. Furthermore, no information about the wind can be used to detect the position of the source. In the approach proposed here, the robot moves along spirals. A spiral can be reset and a new one started, based on the information acquired about gas distribution. This enables the robot to get close to the ejecting source, without relying on airflow measurements. Results from experiments are also described and discussed, to assess the efficiency of the proposed method.     

Arteriovenous fistula: end‐to‐end or end‐to side anastomosis?

The purpose of the present study was to compare the end‐to‐end (ETEa) with the end‐to‐side (ETSa) anastomosis in patients starting hemodialysis by means of radio‐cephalic artero‐venous fistulae (AVF). In our experience, we compared the results, as early failure (EF), late thrombosis (LT), stenosis, steal syndrome, and primary patency (PP), in 2 groups of hemodialysis incident patients that had been placed an AVF by means of ETEa or ETSa. The observation period lasted 24 months for each of the 2 types of AVF, starting from October 2005 to September 2007 for ETEa and from October 2007 to September 2009 for ETSa. One hundred forty patients were included in the present study. We have consecutively performed 99 AVF interventions at the wrist or at the third distal of the forearm, in 70 patients by means of ETEa and 82 AVF interventions in the same anatomical places in 70 patients by means of ETSa. The patients with ETEa had a mean age of 64.4 ± 14.6 years, males were 65.8% and the age dialysis at the end of observation was 10.4 ± 5.7 months. Those with ETSa had a mean age of 65.9 ± 15.5 years and the males were 62.9%, the age dialysis at the end of observation was 9.2 ± 5.5 months. The surgical team was composed by the same nephrologists. The statistical study was performed by means of the χ chi‐square and Fisher's exact test. We have observed more late thrombosis (10% vs. 4.1%) and stenosis (21.4% vs. 2.7%) in ETEa than in ETSa. The number of early thrombosis was similar in the 2 types of anastomosis. The primary patency 1‐year rate was better though not significantly in the ETS (80% vs. 85.7%) In our experience the ETSa provides, overall better results, both regarding the complications and primary survival than ETEa. For the benefits that seem to come from it, we believe, that a broad ETSa in the distal native AVF is preferable to the ETEa.     

A 3D Real‐Scale,Biomimetic, and Biohybrid Model of the Blood‐Brain Barrier Fabricated through Two‐Photon Lithography

The investigation of the crossing of exogenous substances through the blood‐brain barrier (BBB) is object of intensive research in biomedicine, and one of the main obstacles for reliable in vitro evaluations is represented by the difficulties at the base of developing realistic models of the barrier, which could resemble as most accurately as possible the in vivo environment. Here, for the first time, a 1:1 scale, biomimetic, and biohybrid BBB model is proposed. Microtubes inspired to the brain capillaries were fabricated through two‐photon lithography and used as scaffolds for the co‐culturing of endothelial‐like bEnd.3 and U87 glioblastoma cells. The constructs show the maturation of tight junctions, good performances in terms of hindering dextran diffusion through the barrier, and a satisfactory trans‐endothelial electrical resistance. Moreover, a mathematical model is developed, which assists in both the design of the 3D microfluidic chip and its characterization. Overall, these results show the effective formation of a bioinspired cellular barrier based on microtubes reproducing brain microcapillaries to scale. This system will be exploited as a realistic in vitro model for the investigation of BBB crossing of nanomaterials and drugs, envisaging therapeutic and diagnostic applications for several brain pathologies, including brain cancer.     

Far-infrared laser measurement of the refractive index of polypropylene

The refractive index of polypropylene in the far infrared (FIR) is measured by means of a suitably modified laser of a FIR spectrometer. When thin polypropylene films of 12.7-microm nominal thickness are introduced in the optical cavity of a laser at the Brewster angle, the radiation ceases because of the change in the optical path of the laser beam. This change is measured from the displacement of one of the laser mirrors, which is necessary to restore the laser resonance. The refractive index of polypropylene is deduced from this measurement and from the film thickness, as obtained from an independent measurement based in pycnometry. The value obtained for the refractive index is 1.492(15) for the wavelengths between 118.834 and 251.140 microm, for a polypropylene film of 12.71(2)-microm thickness and 0.9049(7) g/cm3 density.     

Intelligent and collaborative Multi-Agent System to generate and schedule production orders

The authors present a Multi-Agent System for constructing and releasing production orders. In a manufacturing enterprise, the generation of production orders consists in a set of coordinated tasks among departments. This has been achieved traditionally as a module of the Production Activity Control (PAC) system. However, classic PAC modules lack collaborative techniques and intelligent behaviour. Moreover, in real-life situations experienced planners take over traditional PAC systems, since the range of possibilities to actually build production orders increases exponentially. To contribute to production planning, we present an intelligent and collaborative Multi-Agent System (MAS), having coordinated two forms to emulate intelligence. The learning capability is achieved by means of a Feed-forward Artificial Neural Network (FANN) with the back-propagation algorithm. The FANN is embedded within a machine agent whose objective is to obtain the appropriate machine in order to comply with requirements coming from the sales department. Also, an expert system is provided to a tool agent, which in turn is in charge of inferring the right tooling. The MAS also consists of a coordinator and a spy. The coordinator agent has the responsibility to control the flow of messages among the agents, whereas the spy agent is constantly reading the Enterprise Information System. Finally, a scheduler agent schedules the production orders. The resultant MAS improves the current form to plan production in a factory dedicated to produce labels.     

Load Testing of a Closed-Ended Pipe Pile Driven in Multilayered Soil

Piles are often driven in multilayered soil profiles. The accurate prediction of the ultimate bearing capacity of piles driven in mixed soil is more challenging than that of piles driven in either clay or sand because the mechanical behavior of these soils is better known. In order to study the behavior of closed-ended pipe piles driven into multilayered soil profiles, fully instrumented static and dynamic axial load tests were performed on three piles. One of these piles was tested dynamically and statically. A second pile served as reaction pile in the static load test and was tested dynamically. A third pile was tested dynamically. The base of each pile was embedded slightly in a very dense nonplastic silt layer overlying a clay layer. In this paper, results of these pile load tests are presented, and the lessons learned from the interpretation of the test data are discussed. A comparison is made of the ultimate base and limit shaft resistances measured in the pile load tests with corresponding values predicted from in situ test-based and soil property-based design methods.     

An algorithm for the structural analysis of state space: synthesis of nonlinear observers

The problem addressed is the linearization of multi‐input multi‐output (MIMO) nonlinear systems by a generalized state coordinates transformation and generalized input–output injection, in order to design an observer. This observer will have linear error dynamics. The goal is to bring together two observers design approaches: a structural one and a numerical one. Necessary and sufficient conditions for the existence of a linearizing generalized state transformation are obtained by an algebraic way and without computing the input–output differential equations. The main result tests integrability conditions of differential one‐forms derived from the state space representation and is applicable to a large subclass of nonlinear systems. Copyright © 2001 John Wiley & Sons, Ltd.     

Spatially modulated illumination microscopy allows axial distance resolution in the nanometer range

For an improved understanding of the structural basis of cellular mechanisms, it is highly desirable to develop methods for a detailed topological analysis of biological nanostructures and their dynamics in the interior of three-dimensionally conserved cells. We present a method of far-field laser fluorescence microscopy to measure relative axial positions of pointlike fluorescent targets and the distance between each target in the range of a few nanometers. The physical principle behind this approach can be extended to the determination of three-dimensional (3D) positions and 3D distances between any number of objects that can be discriminated owing to their spectral signature, thus allowing topological measurements so far regarded to be beyond the capabilities of light microscopy.