Artificial neural network identification of heterotrophic marinebacteria based on their fatty-acid composition

The traditional approach to biochemical identification of marine fresh isolates requires considerably long culture preparation times and large quantities of expensive materials and reagents, and the results are not very reliable. On the other hand, taxonomy tests based on DNA composition, although sensitive and reliable, require long execution times and high costs, A method is presented for the classification of fatty-acid profiles, extracted from marine bacteria strains, at genus level based on supervised artificial neural networks. The proposed method allows the correct identification of all patterns belonging to the training set and almost all patterns belonging to the test set. Moreover, a quantitative measure of the importance of each fatty acid for bacterial classification is also achieved. This measure allows the determination of a cluster of fatty acids to be controlled with greater care. The results show that the proposed method is reproducible and rapid, so that it can be routinely used in the marine microbiology laboratory to identify fresh isolates     

Pharmacological Promiscuity: Dependence on Compound Properties and Target Specificity in a Set of Recent Roche Compounds

What parameters determine promiscuity? A compound's potential for promiscuity (pharmacological activity at multiple targets) may be influenced by molecular parameters such as ionization state, lipophilicity, and molecular weight. In an analysis of recent Roche compounds we found that a positive charge is an important determinant for potential promiscuity; aminergic activity was found to be the main reason for overt promiscuity.

     

A superconvergent hybridisable discontinuous Galerkin method for linear elasticity

The first superconvergent hybridisable discontinuous Galerkin method for linear elastic problems capable of using the same degree of approximation for both the primal and mixed variables is presented. The key feature of the method is the strong imposition of the symmetry of the stress tensor by means of the well known and extensively used Voigt notation, circumventing the use of complex mathematical concepts to enforce the symmetry of the stress tensor either weakly or strongly. A novel procedure to construct element by element a superconvergent postprocessed displacement is proposed. Contrary to other hybridisable discontinuous Galerkin formulations, the methodology proposed here is able to produce a superconvergent displacement field for low‐order approximations. The resulting method is robust and locking‐free in the nearly incompressible limit. An extensive set of numerical examples is utilised to provide evidence of the optimality of the method and its superconvergent properties in two and three dimensions and for different element types.     

Tuning of a Vertical Spin Valve with a Monolayer of Single Molecule Magnets

The synthesis and the chemisorption from solution of a terbium bis‐phthalocyaninato complex suitable for the functionalization of lanthanum strontium manganite (LSMO) are reported. Two phosphonate groups are introduced in the double decker structure in order to allow the grafting to the ferromagnetic substrate actively used as injection electrode in organic spin valve devices. The covalent bonding of functionalized terbium bis‐phthalocyaninato system on LSMO surface preserves its molecular properties at the nanoscale. X‐ray photoelectron spectroscopy confirms the integrity of the molecules on the LSMO surface and a small magnetic hysteresis reminiscent of the typical single molecule magnet behavior of this system is detected on surface by X‐ray magnetic circular dichroism experiments. The effect of the hybrid magnetic electrode on spin polarized injection is investigated in vertical organic spin valve devices and compared to the behavior of similar spin valves embedding a single diamagnetic layer of alkyl phosphonate molecules analogously chemisorbed on LSMO. Magnetoresistance experiments have evidenced significant alterations of the magneto‐transport by the terbium bis‐phthalocyaninato complex characterized by two distinct temperature regimes, below and above 50 K, respectively.     

Model-driven engineering for mobile robotic systems: a systematic mapping study

Software and Systems Modeling - Mobile robots operate in various environments (e.g. aquatic, aerial, or terrestrial), they come in many diverse shapes and they are increasingly becoming parts of...     

Repeated Richardson extrapolation to reduce the field discretization error in computational fluid dynamics

ABSTRACT

The aim of this study is to extend the use of repeated Richardson extrapolation to one-dimensional (1D) and two-dimensional (2D) fields in computational fluid dynamics (CFD). The following two methods are tested: completed Richardson extrapolation (CRE), a method that has been used previously in the literature, and full Richardson extrapolation (FRE), a new method developed in this study. The Poisson’s, advection–diffusion, Laplace’s, and Burgers’ equations are solved using the finite difference method. The CRE and FRE methods were found to significantly reduce the discretization error of the numerical solutions for all nodes of the grid.     

Numerical study of flow anisotropy within a single natural rock joint

The paper investigates the flow anisotropy within a natural joint subjected to mechanical shear. The cubic law is the simplest way to describe fluid flow through rock joints but because of rock wall roughness, deviations from this model have been observed. The Reynolds equation usually gives better results. In this study, micro-scale roughness is taken into account to define a reduced coefficient of permeability. Numerical simulations have been carried out by applying Darcy's law to the rock joint, described as an equivalent porous medium. The numerical simulations are based on experimental data obtained by Hans (PhD, Grenoble, 2002) from a series of hydromechanical shear tests on a rock joint replica. The numerical results have been compared to the experimental ones, and to the results obtained by applying the Reynolds equation, to assess the relevance of the simulations. For the fracture studied, the approach proposed herein can reproduce relatively well the experimental flow anisotropy, and provides consistent values of flow rates, whereas the Reynolds equation tends to give higher flow rates.     

Antibacterial agents and cystic fibrosis: synthesis and antimicrobial evaluation of a series of N-thiomethylazetidinones

The increasing emergence of multidrug-resistant microorganisms is one of the greatest challenges in the clinical management of infectious disease. New antimicrobial agents are therefore urgently required, particularly in the treatment of chronic and recurrent infections often associated with antibiotic-resistant pathogens, as in the case of cystic fibrosis (CF) patients. This study reports the antibacterial activity of a series of monocyclic β-lactams with an alkylidenecarboxyl chain or electron-withdrawing groups such as 4-OAc, 4-SAc, and 4-SO(2)Ph at the C4 position of the ring. N-Unsubstituted and N-thiomethyl derivatives were compared. A total of 33 azetidinones were tested for their activity against Gram-positive and Gram-negative bacterial clinical isolates. The combination of an N-thiomethyl group and a benzyl ester on the 4-alkylidene side chain were found to increase the potency against Gram-positive bacteria. The N-thiomethyl group clearly elevated the activity of 4-acetoxyazetidinones relative to the corresponding NH derivatives. The most active compounds showed minimum inhibitory concentration (MIC) values of 4 and 8 mg L(-1) against methicillin-resistant Staphylococcus aureus isolated from pediatric patients with CF.     

The most dangerous flaw orientation in brittle materials and structures

In the present paper a sheet of material is considered. It is loaded by uniaxial tensile stress and contains a random distribution of flaw orientations, with the flaws thought of as flat pre-cracks of comparable length, and with all crack planes being oriented perpendicular to the faces of the sheet. Intuition suggests that the most likely flaw to initiate fracture, which will be termed the “most dangerous defect”, lies orthogonally to the major load axis. The purpose of the present paper is to show that such an assumption is incorrect. Neither the most dangerous defect nor the first increments of crack growth will be oriented perpendicularly to the stress direction (nor will they be co-planar with the orientation of the most critical flaw).