Synthesis of Some Carhamates of Steroidal Lactams and Lactones as Possible Alkylating Agents

16-0xo-l 7 a-aza-5o.-androstan-3-yl N-alkyl/phenylcarbamates (I-V), 16-oxo-l 7a-oxa-5a-androstan-3-yl N-ethylcarbamate (VI), 16-oxo-l 7a-aza-5-androsten-3-yl N-alkyl/phenylcarbamates (VII-:IX) and 4-oxo-3-aza-A-homo-4a-androsten-l 7B-yl N-phenylcarbamate (X) were prepared by the action of substituted isocyanate on the corresponding steroidal lactams or lactone

Design of a Computer Code To Evaluate the Influence of the Harmonics in the Electrical Networks

This paper aims to present the design of a computer code (HPFCODE), forcalculate a power flow and power losses in power systems under theinfluence of harmonics, using the GUI in MATLAB. After described theprogram was run for two networks IEEE 6 nodes and IEEE 14 nodes. Thepower flow by Newton-Raphson method was calculated as the losses ofactive and reactive power in the lines, respectively, where the loads arelinear and nonlinear (Static Var Compensator(SVC), Thyristor controlledReactor(TCR), and Unified Power Flow Controller ((UPFC)), The resultswere almost consistent and show the influence of higher harmonics onpower losses in electrical networks.DOI:http://dx.doi.org/10.11591/ijece.v2i5.146

Lagrangian and ALE Formulations For Soil Structure Coupling with Explosive Detonation

Simulation of Soil-Structure Interaction becomes more and more the focus of computational engineering in civil and mechanical engineering, where FEM (Finite element Methods) for soil and structural mechanics and Finite Volume for CFD (Computational Fluid Dynamics) are dominant. New advanced formulations have been developed for FSI (Fluid Structure Interaction) applications using ALE (Arbitrary Lagrangian Eulerian), mesh free and SPH (Smooth Particle Hydrodynamic) methods. In defence industry, engineers have been developing protection systems for many years to reduce the vulnerability of light armoured vehicles (LAV) against mine blast using classical Lagrangian FEM methods. To improve simulations and assist in the development of these protections, experimental tests and new numerical techniques are performed. Initial conditions such as the loading prescribed by a mine on a structure should be simulated adequately in order to conduct these numerical calculations. The effects of blast on structures often depend on how the initial conditions are estimated and applied. This article uses two methods to simulate a mine blast, namely the classical Lagrangian as well as the ALE formulations. The comparison was carried out for a simple and also a more complex target. Particle methods as SPH method can also be used for soil structure interaction

Développement d'algorithmes de Plasmode longitudinaux pour l'évaluation d'approches d'ajustement pour la confusion et illustration pour l'étude de l'effet d'une exposition cumulée aux stresseurs psychosociaux au travail

Le biais de confusion peut affecter tous les types d’études d’observation. Il apparaît lorsque la caractéristique étudiée est associée à un facteur de perturbation complémentaire et que ce dernier fait croire à l’existence d’une relation de cause à effet entre la caractéristique étudiée et l’issue. Des méthodes d’ajustement pour le biais de confusion, notamment les modèles structurels marginaux, peuvent être utilisées pour corriger ce type de biais. Ces modèles n’ont toutefois été utilisés qu’une seule fois pour l'étude de l’effet d’une exposition cumulative aux stresseurs psychosociaux au travail sur la pression artérielle. L’objectif principal de ce mémoire était de comparer différents estimateurs des paramètres d’un modèle structurel marginal à des approches classiques. Nous avons considéré les estimateurs par pondération inverse de la probabilité de traitement, le calcul-g, le maximum de vraisemblance ciblé avec et sans SuperLearner. Ces estimateurs ont d’abord été utilisés pour estimer l’effet d’une exposition cumulée aux stresseurs psychosociaux au travail sur la pression artérielle systolique dans le cadre d’une étude de cohorte prospective de 5 ans. Cette analyse a révélé des différences significatives entre les estimateurs. Puisqu’il s’agit de données réelles, il est toutefois impossible de déterminer quelle méthode produit les résultats les plus valides. Pour répondre à cette question, nous avons développé deux algorithmes de simulation de données longitudinales de type Plasmode, l’un utilisant des modèles paramétriques et l’autre utilisant des approches non paramétriques. Les simulations Plasmode combinent des données réelles et des données synthétiques pour étudier les propriétés dans un contexte connu, mais similaire au contexte réel. Au vue des résultats, nous avons conclu que les modèles structurels marginaux représentent des approches pertinentes pour estimer l’effet des stresseurs psychosociaux au travail. Nous recommandons particulièrement d’utiliser la méthode de maximum de vraisemblance ciblé avec et sans SuperLearner. Cependant, cela nécessite un effort supplémentaire en termes d’implantation de code et de temps d’exécution

New valid inequalities for knapsack and fixed-charge problems

A wide variety of important problems, in Operational Research and other fields, can be modelled as optimisation problems with integer-constrained variables. Algorithms and software for integer programming have improved substantially. One of the key ingredients to this success is the use of strong valid linear inequalities, also known as cutting planes. A key concept is that the convex hull of feasible solutions forms a polyhedron. One strand of the literature on cutting planes is concerned with the knapsack polytope. In the 1970s, Balas and Wolsey derived a family of inequalities, called lifted cover inequalities (LCIs), for the knapsack polytope. We have taken a lifting procedure due to Balas, and shown that it can be substantially improved, so that it yields stronger and more general LCIs. In 2000, Carr and co-authors introduced another family of valid inequalities for the knapsack polytope. These inequalities, called knapsack cover inequalities, can be rather weak. We have used two lifting procedures to strengthen these inequalities. The first procedure is based on integer rounding, whereas the second uses superadditivity. Another important class of optimisation problems are those that involve fixed charges. In 1985, Padberg, Van Roy and Wolsey introduced a procedure which enables one to take known valid inequalities for the knapsack polytope, and convert them into valid inequalities for the fixed-charge polytope. We have shown how this procedure can be extended to obtain a wider family of inequalities for the fixed-charge and single-node flow polytopes. Finally, we have considered problems where a fixed charge is incurred if and only if at least one variable in a set takes a positive value. We have derived strong valid inequalities for these problems and shown that they generalise and dominate a subclass of the flow cover inequalities for the classical fixed-charge problem

Deployment of a Neo-Hookean membrane: experimental and numerical analysis

The aim of this research is to assess the response of a thin membrane subjected to high-pressure gas loading for inflation. This procedure is applied during the design process of the membrane structure to allow the product to resist high-pressure loading and to further characterize the hyper-elastic material. The simulation in this work considers the standard procedures used in the LS-DYNA software, which applies such assumptions as a uniform airbag pressure and temperature in addition to a more recently developed procedure that takes into account the fluid-structure interaction between the inflation gas source and the hyper-elastic membrane; this approach is referred to as the Arbitrary Lagrangian Eulerian (ALE) formulation. Until recently, to simulate the inflation of the hyperelastic membrane, a uniform pressure based on a thermodynamic model or experimental test has been applied to the structure as the boundary conditions. To conserve CPU time, this work combines both methods; the fluid structure coupling method is used at an earlier stage in which the fluid is modeled using full hydrodynamic equations, and at the later stage, the uniform pressure procedure is applied, and the fluid mesh and analysis are removed from the computation. Both simulations were compared to test data, indicating satisfactory correlation with the more recently developed procedure, the ALE theory, which showed the greatest accuracy both in terms of graphical and schematic comparison, particularly in the early stages of the inflation process. As a result, the new simulation procedure model can be applied to research on the effects of design changes in the new membrane

First identification of an Escherichia coli clinical isolate producing both metalloβ-lactamase VIM-2 and extended-spectrum β-lactamase IBC-1

AbstractAn Escherichia coli strain with decreased susceptibility to carbapenems was isolated from a hospitalised patient in Athens, Greece. The strain was resistant to all β-lactams, including aztreonam, whereas the MIC of imipenem and meropenem was 0.5 mg/L. A positive EDTA-disk synergy test suggested the production of a metallo-β-lactamase. PCR experiments revealed the presence of the blaVIM-2, blaIBC-1 and blaTEM-1 genes. Resistance to β-lactams was not transferable by conjugation. This is the first report of a clinical isolate of E. coli producing VIM-2, and the first report of the coexistence of blaVIM-2 and blaIBC-1 in a single clinical isolate

Valid inequalities for mixed-integer programmes with fixed charges on sets of variables

We consider mixed 0-1 linear programs in which one is given a collection of (not necessarily disjoint) sets of variables and, for each set, a fixxed charge is incurred if and only if at least one of the variables in the set takes a positive value. We derive strong valid linear inequalities for these problems, and show that they generalise and dominate a subclass of the well-known flow cover inequalities for the classical fixed-charge problem