Crystal growth, structure and electrical properties of thorium phosphorosulfide

Single crystals of thorium phosphorosulfide have been grown by the chemical vapour transport method. The X-ray diffraction examination showed that the unit cell of the crystals belongs to a tetragonal system of the PbFCl-type structure. The basal plane resistivity ρ(300 K)=64 μΩ cm and thermoelectric power S(300 K)=−7.7 μV/K, examined between 0.4 and 315 K, show metallic behaviour.     

Applications of small iridium-based mercury electrodes to high concentrations of depolarizers

Voltammetric and microscopic data on the analytical properties of small iridium-based (127- μm diameter) mercury film electrodes are presented. A method of estimating and controlling the size of the deposit is described. The voltammetric behaviour of electrodes with mercury deposits varying from a film to a near-hemisphere is discussed for linear-scan, differential- and normal- pulse voltammetry. The systems Pb²⁺/Pb, Fe³⁺/Fe²⁺ and Co²⁺/Co, are used to show that, by changing the size of the deposit, either time-dependent or almost time-independent (steady-state) voltammograms can be obtained under the same instrumental conditions. Possible applications to the determination of high concentrations of depolarizers are outlined; voltammetric data for the determination of lead in the range 10–120 mM are presented. The evaluation of diffusion coefficients is discussed.     

Effective dimensionality approach to the RKKY interaction in multilayer systems

We consider RKKY interaction in a quasi 2D system with nonparabolic dispersion. In our paper we calculate the RKKY range function assuming the in-layer confinement via effective dimensionality approach. We show, that indirect magnetic exchange in our system can be modelled by the effective spectral dimension which equals one.     

Investigation of adsorption and vertical migration of137Cs in three kinds of soil at Lublin vicinity

The results of field, column and laboratory studies carried out on three types of mineral soils are encloses presented. Based on the field tests, average migration rates of¹³⁷Cs were calculated. The highest rate was found for the brown soil (FAO/UNESCO—Cambisol). Cesium migrated with the lowest rate in the podzol soil (FAO/UNESCO—Cambic Podzol). The column experiments confirmed the above observation. In laboratory tests the adsorption and desorption isotherms of Cs were determined on samples taken from 0–2 cm layers of each soil profile. It was found from the calculated partition coefficients that Cs is always irreversibly bonded to some extent, but it appears to be completely and irreversibly immobilized on the podzol soil. The permanent retention of cesium in the podzol soil was also confirmed by microcalorimetric studies. The desorption energy was negligibly small and amounted to −0.21 mJ/g. In the brown soil, containing prevailing amounts of loamy minerals, the desorption energy was found to be 106.89 mJ/g. The investigations are supplemented by the sorption kinetics measurements. These indicate that the adsorption equilibrium is reached after a dozen, up to twenty or so minutes.     

The spherical oil agglomeration of barite suspensions in the presence of surfactant and cosurfactant

The spherical agglomeration of barite particles using oil in the presence of both surfactant and cosurfactant was studied. It was found that the mineral suspension needed a critical surfactant concentration to initiate oil agglomeration. The addition of long-chain aliphatic alcohols to the organic phase decreased the critical surfactant concentration. This phenomenon was ascribed to a screening effect of alcohol molecules in the adsorption layer of surfactant. When sodium chloride was added to the solution the spherical agglomeration disappeared even though the surfactant adsorption at the barite/solution interface increased. It was concluded that the disappearance of oil agglomeration was caused by a bilayer of the surfactant which was formed on the barite surface. In the barite—surfactant—alcohol—oil—brine system the agglomeration process is only realized with the long-chain alcohols. This behaviour can be explained by microemulsion formation at the mineral/solution interface.     

Crystal structure and magnetic properties of HoPt2Si2

The crystal structure of HoPt₂Si₂ was determined using powder neutron diffraction data. It is tetragonal, CaBe₂Ge₂ type (space group P4/_n mm). Neutron diffraction and magnetometric measurements indicate that HoPt₂Si₂ remains paramagnetic at the temperature of 2.0 K.     

Crystal and molecular structures of 1-isoquinolyl(phenyl)methyl benzoate and 1-isoquinolylisopropyl benzoate

Both of the title compounds crystallize in the monoclinic system: C₂₃H₁₇NO₂ (Ib),P2₁/c,a = 8.970(1),b = 22.629(5),c = 9.101(1) Å, = 106.08(1) °,Z = 4,D _x = 1.27 Mg m^–3; C₁₉H₁₇NO₂ (Ic),P2₁/a,a = 15.225(2),b = 6.429(1),c = 17.190(1) Å, = 112.99(1) °,Z = 4,D _x = 1.25 Mg m^–3. The structures were solved and refined by standard methods, both toR 0.04. In compound Ib, a weak intramolecular interaction is observed between the nitrogen atom from the isoquinoline ring and the carbon atom from the carbonyl group, with the N(2) . C(18)distance being 2.98 Å. In compound Ic, the PhCO₂ -fragment is twisted in the opposite direction to that in compound Ib, without hydrogen bonding. The pK _a and IR data were considered in the light of the results of the X-ray investigation.     

Crystal and molecular structure of 17-β-methyllupanine perchlorate

The formula of the title compound is C₁₆H₂₇ClN₂O₅,MW = 362.9 orthorhombic,P2₁2₁2₁,a = 8.403(1),b= 13.133(1),c= 15.972(2) Å,Z = 4,D _x = 1.37 g cm^–3, (CuK) = 2.2 mm^-1. The lupanine skeleton has atrans-trans configuration. The ringA has a half-chair conformation, theB andD rings adopt a chair form, and theC ring forms a boat. The lupanine cations are linked together by the intermolecular hydrogen bonds forming infinite chains alongb. The N(16) ... O(C2) distance is 2.763(7) Å.     

Dye-labeled silver nanoshell-bright particle

Silica beads with average diameters of 40-600 nm were prepared, and Ru(bpy)3(2+) complexes were incorporated into the beads. These beads were coated by silver layer by layer to generate porous but continuous metal nanoshells. The thicknesses of these metal shells were 5-50 nm. The emission band from the dyes in the silica cores was more narrow and the intensity was enhanced with growth of silver shell thickness due to coupling of the emission light from Ru(bpy)3(2+) in the cores with the metal plasmon from the silver shells. The enhancement of emission intensity was also dependent on the size of the silica core, showing that the enhancement efficiency decreased with an increase in the size of the silica beads. Lifetime measurements support the coupling mechanism between the dye and metal shell. This study can be used to develop novel dye-labeled metal particles with bright and narrow emission bands.     

Effect of Inoculated Lactic Acid Fermentation on the Fermentable Saccharides and Polyols,Polyphenols and Antioxidant Activity Changes in Wheat Sourdough

Inoculation of sourdough allows the fermentation medium to be dominated by desired microorganisms, which enables determining the kinetics of the conversion of chemical compounds by individual microorganisms. This knowledge may allow the design of functional food products with health features dedicated to consumers with special needs. The aim of the study was to assess the dynamics of transformations of fermentable oligosaccharide, disaccharide, monosaccharide and polyol (FODMAP) compounds from wheat flour as well as their antioxidant activity during inoculated and spontaneous sourdough fermentation. The FODMAP content in grain products was determined by the fructan content with negligible amounts of sugars and polyols. To produce a low-FODMAP cereal product, the fermentation time is essential. The 72 h fermentation time of L. plantarum-inoculated sourdough reduced the FODMAP content by 91%. The sourdough fermentation time of at least 72 h also positively influenced the content of polyphenols and antioxidant activity, regardless of the type of fermentation. The inoculation of both L. plantarum and L. casei contributed to a similar degree to the reduction in FODMAP in sourdough compared to spontaneous fermentation.