Self-Organising Map for Data Imputation and Correction in Surveys

This paper is dedicated to erroneous data detection and imputation methods in surveys. We describe experiments conducted under the scope of a European project for studying new statistical methods based on neural networks. We show that the self-organising map can be used successfully for these tasks. A self-organising map is calibrated according to the available observations, described through a set of correlated variables handled together. The map can then be used both to detect erroneous data and to impute values to partial observations. We apply these principles to a real size transport survey database. We show that the performance of our imputation model compares well to other classical methods, and that the use of a self-organising map for data correction provides a performing system fordata validation, data correction and data analysis.     

Biomaterial‐Induction of a Transplantable Angiosome

Creating transplantable vascular networks (angiosomes) that are fed and drained by vessels large enough to be surgically reconnected is key to harnessing the potential of regenerative medicine and advancing reconstructive surgical techniques. Currently, the only way to create a new angiosome is nontrivial and involves pressurizing a vein graft by its surgical attachment to an artery forming an arteriovenous loop (AVL). Material induction of a venous angiosome is reported, by placement of a 3D printed microporous monetite scaffold around a vein and its transplantability is further demonstrated. When the transplanted venosome is cut, it bleeds, illustrating potential reconstructive functionality. The volume of blood vessels generated by biomaterial‐induction is as great as by AVL. Direct contact of the material with the vein does not appear to be critical to luminal sprouting, and wrapping the implant in a silicone membrane significantly reduces sprouting. Pilot studies with microporous polymeric scaffolds induce far less vascular invasion. After 4 weeks, monetite scaffolds are extensively vascularized and can be transplanted to an arterial vessel. This report is significant since a lack of tools to control vascular generation is an impediment to the treatment of several conditions that give rise to tissue ischemia and tissue reconstruction.     

Effect of surface properties of activated carbons on surfactant adsorption kinetics

This research investigates the adsorption properties of three activated carbons (AC) derived from coconut, coal, and wood origin. A linear relationship exists between the number of water molecules adsorbed onto each AC and the oxygen content determined elemental analysis and XPS. An inverse linear relationship exists between the plateau amount of dodecanoic acid anionic surfactant and the oxygen content on the surface of ACs. The surface charge on each AC’s surface had a linear relationship with the plateau amount of dodecanoic acid. A plug-flow heterogeneous surface diffusion model (PFHSDM) for a fixed-bed adsorption process was developed to describe the adsorption kinetics in a fixed-bed column. The model represents axially dispersed plug-flow, external mass transfer, adsorption equilibrium on the fluid-particle interface, and intraparticle diffusion. The larger molecular dimension of the dodecanoic acid as a more hydrophobic entity than octanoic acid led to a faster external mass transfer rate but a slower surface diffusion rate as estimated from the PFHSDM. The interaction between the organic moiety of surfactant and the AC surface chemistry such as surface oxygen content and surface charge contributes to the adsorption performance in both to the adsorption equilibrium and kinetics.     

Synthesis and characterization of ionomers based on telechelic phosphonic polyether or aromatic polyesters

A new method to prepare ionomers bearing terminal ionic groups has been developed by modification of different hydroxyl terminated oligomers and using vinyl phosphonic acid as reagent. The different oligomers have been characterized by NMR, MALDI-TOF, SAXS, SEM-EDX, thermal analysis and their ionic crosslinking was achieved using different cations. Characterization of the network was performed and proved that an efficacious crosslinking was reached depending on the nature of the cations.     

Characterization of networks from photoreactive copolymers: an attempt to correlate chemical composition to network structure

The photoreactivity of polystyrene bearing photoreactive benzil (BZ) pendant groups was studied. Upon irradiation (λ > 370 nm), BZ groups were transformed to benzoyl peroxide (BP) groups that caused crosslinking of the polymer upon heating. The main goal of this study was to characterize the final network. Melt viscoelasticity is a powerful method to assess some specific parameters of a crosslinking process (gel point, crosslink density). Classical methods based on low‐frequency slope variations, such as the Winter and Chambon method, were successfully applied. A good correlation was established between the content of BP groups after the first irradiation and the final density of the network after crosslinking. It was determined that at least two peroxidic species (BP groups) per macromolecular chain are necessary to reach the gel point. The concentration of BZ groups and their conversion into BP groups are the factors supporting a denser network. Copyright © 2010 Society of Chemical Industry     

Propriétés psychométriques d'une version canadienne-fran?aise du Questionnaire des expériences dépressives.

The present study evaluates a French-Canadian version of the Depressive Experiences Questionnaire, originally developed by Blatt, D'Afflitti, et Quinlan (1976), to measure two personality dimensions predisposing to depressive affect, Dependency and Self-Criticism. Factor analysis with 762 undergraduate students showed a very high degree of conformity with the original version in terms of the number of factors, variance explained and the pattern of factor loadings for each scale. Congruence of factor scores calculated with the solutions derived from the English and French principal component analysis was very high, but somewhat lower for the Self-critical dimension for male subjects. The scales of the French-Canadian Questionnaire des Expériences Dépressives correlated with a measure of depression, and showed adequate test-retest reliability over an 8-week period. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Genetische Präimplantationsdiagnostik (PGD) in europäischer Perspektive

Ethik in der Medizin -     

Broken rotor bars detection by a new non-invasive diagnostic procedure

A new technique of diagnosing data for broken rotor bars in induction motors derived from two of the three stator currents, the Beirut diagnostic procedure (BDP) is presented in this paper. The theoretical principles directly related to the application of this diagnostic technique are described, emphasizing the use of a severity factor in order to evaluate the extension of the fault. Defining the severity factor as the normalized amplitude of the fault characteristic frequency enables us to draw up a table of comparison of several usual electric diagnostic methods. Besides the traditional one-phase current spectrum analysis, values of the severity factor related to electrical signals like the instantaneous powers, the current space vector modulus and finally related to the new Beirut diagnostic method are analyzed with respect to the variation of the power factor angle and of the sum of the two current side-band angular displacement. The BDP offers several advantages over the usual motor current signature analyses (MCSA) methods: it is shown how the proposed severity factor applied to the new diagnostic technique is not dependent on motor parameters such as the power factor angle and the fault type which is not the case of the instantaneous powers. In addition, the BDP has the advantage of detecting easily fault characteristic frequencies, which is not possible via diagnostic methods that use the detection of two side-band components as in the simple current spectrum.By theoretical analysis, computer simulations, and laboratory experiments, it is shown that the new method enhances the reliability of diagnostics of broken rotor bars in induction motor.     

Experimental and numerical study of creep and creep rupture behavior of PA6

Polyamide 6 (PA6) is a semi-crystalline polymer utilized in many structural components working under steady load. At room temperature, PA6 exhibits time dependent (viscoplastic) deformation. The aim of this work is to investigate the mechanical response and the crack growth of PA6 under creep conditions.The experimental database consists of tests carried out on smooth and notched round bars. Load versus displacement curves were recorded for monotonic tests tensile at various crosshead speeds. Then, creep tests at constant load were performed allowing the record of the creep strain history according to the applied load.Microscopic observations highlight the initial spherulitic structure.Smooth and notched specimens were utilized in order to identify and to validate material coefficients dedicated for analytical modeling. The non linear fracture mechanics for creeping solids was applied to results on “pre-cracked” specimens. For this kind of loading, use of the load parameter C^∗ is recommended.By plotting C^∗ values versus time to failure, a unique correlation was obtained. The knowledge of this master curve allows lifetime assessment of PA6 cracked bodies.