Determination of microelement distribution in different components of soil-plant systems

The leaves, stem, and roots of two types of shrubs (tea (Camellia sinensis) and sweet leaf (Sauropus androgynus)) and two types of herbs (vetiver grass (Vetiveria zizanioides L. Nash) and maize (Zea mays L)) and the Thucuc soil where the plants were growing were collected to be studied. The contents of 22 elements in the samples were determined by three methods: X-Ray fluorescence analysis (XRFA), gamma activation analysis (GAA), and the tracking method to study the distribution of these elements in plants and the soil-plant relationship. This study was carried out at the Flerov Laboratory of Nuclear Reactions (FLNR), Joint Institute for Nuclear Research (JINR), Dubna, Russia. The distribution of the elements in the soil-plant system was studied.     

On optimality conditions for vector variational inequalities

Optimality conditions for weak efficient, global efficient and efficient solutions of vector variational inequalities with constraints defined by equality, cone and set constraints are derived. Under various constraint qualifications, necessary optimality conditions for weak efficient, global efficient and efficient solutions in terms of the Clarke and Michel–Penot subdifferentials are established. With assumptions on quasiconvexity of constraint functions sufficient optimality conditions are also given.     

Polycatenar, bent-core pyridines and their discotic complexes with silver(I)

New, bent-core, polycatenar pyridine mesogens are described. Binding to silver(I) leads to complexes properly described as discotic.     

Unsymmetrical broadside-coupled coplanar waveguides for loose-and tight-coupling mic and mmic applications

New broadside-coupled coplanar waveguides (CPW) having a completely asymmetrical structure, suitable for hybrid and monolithic microwave and millimeter-wave integrated circuits requiring broad bandwidths as well as loose and tight couplings, is proposed and examined for the first time. The results of the inivestigation, performed based on the spectral-domain analysis, demonstrate the versatility of the asymmetrical broadside-coupled CPW as compared to its symmetrical counterpart.     

Mass spectrometric studies of phosphodiesters linked to oxysterols and nucleosides,a family of biologically potent oxygenated sterols

Negative-ion fast atom bombardment mass spectra of five compounds resulting from combinations between oxysterols and nucleoside analogues linked by phosphodiester bonds are presented and interpreted. This method seems to be the most appropriate for elucidating the structure of these complex, labile and non-volatile phosphate-containing molecules which exhibit important antitumour and/or immunosuppressive activities.     

Axisymmetric three-dimensional finger solutions in Mullins-Sekerka equation

In this paper, we study the existence problem of axisymmetricthree-dimensional finger solutions of Mullins–Sekerkaequation. The finger solutions are travelling wave solutionswhose finger-shaped interfaces are moving along a certain directionat a constant speed within a cylindrical domain. The existenceof at least one axisymmetric three-dimensional finger solutionis obtained through a fixed-point argument of the Hilbert transformation.     

Contrôle par rotation ou par aspiration de l'écoulement autour d'un cylindre calculé par Simulation des Grandes Échelles

Control of the flow around a circular cylinder is studied using Large Eddy Simulation. The influence of control by rotation and suction on the flow characteristics is considered for several Reynolds numbers. Comparisons with experiments were conducted at $\mathit{Re}={10}^5$ for the flow with and without control. A drag reduction up to 30% is obtained for an usual suction intensity. To cite this article: G. Fournier et al., C. R. Mecanique 333 (2005).     

Quantitative determination of fucoidan using polyion-sensitive membrane electrodes

The use of polyanion and polycation-sensitive membrane electrodes to detect five different preparations of fucoidan is described. Unlike linear polyanionic molecules previously measured with polymer membrane-based electrochemical sensors, fucoidans from marine brown algae are all highly branched, sulfated polysaccharides with varying charge densities and structures, depending on the species of seaweed, method of extraction used and extent of purification. When tridodecylmethylammonium (TDMA) was used as the ion-exchanger, a large, non-equilibrium EMF response was observed over a concentration range of 0.5–50 μg mL⁻¹ fucoidan. Fucoidan was also measured by titration with polycationic protamine, using a dinonylnaphthalene sulfonate (DNNS)-doped membrane electrode as the potentiometric endpoint detector. Potentiometric titration was used to determine the binding ratio between protamine and fucoidan at the neutralization endpoint for each fucoidan preparation. This binding ratio was then used to successfully determine the fucoidan content of commercially available nutritional supplements. Fucoidan was also measured in undiluted blood serum, demonstrating that this method may be applicable for measuring fucoidan for clinical applications.     

Synthesis of PbSeTe single ternary alloy and core/shell heterostructured nanocubes

We report a robust method for synthesis of monodisperse PbSeTe single ternary alloy and core/shell heterostructured nanocubes, respectively. The key synthetic strategy to produce such different classes of nanocubes is to precisely control the time of reaction and successive growth. The crystallinity, shape/size distributions, structural characteristics, and compositions of as-prepared nanocubes, both ternary alloy and core/shell, were carefully studied. A plausible growth mechanism for developing each type of lead chalcogenide nanocubes is proposed. These delicately designed PbSeTe nanoscale architectures offer tunable compositions in PbSeTe ternary alloy and nano-interfaces in core/shell nanocubes, which are the critical factors in controlling thermal conductivity for applications in thermoelectrics.