Investigations of the separation of Np,Pa, U,Th and ree in geological samples

In the first part some methods of the radiochemical neutron activation analysis of U, Th and REE trace amounts in geological samples have been studied. They are: (i) cation exchange and extraction, and (ii) extraction chromatography. The behaviour of U and Th was also observed and conclusions were made regarding the applicability of the methods for the rocks which are rich in U and Th but depleted of REE. The method is recommen ded for the selective separation of U and Th. The second part represents an effective separation method for the determination of all REE and Th contents in monazites.     

Spiral resonator manufactured on AlN ceramics to filter the coupled wave between patch antennas

The objective of this paper was to present an alternative technique of manufacturing the unit cells of spiral-shaped resonators (SR) on the aluminium nitride (AlN) ceramics. In this technique the AlN plane surface is irradiated by the Yb:glass medium-power laser (1.06 µm). As a result of the irradiation by a focused laser beam (a laser beam power up to 20 W), the rupture of the aluminium and nitrogen physical bonds occurs. Under such circumstances the conductive aluminium “paths” are formed on the originally insulating ceramic surface. Upon obtaining low ohmic conductive paths, this method makes for the feasible manufacturing of metamaterial structures. In carried out studies, the usage of such structures to suppress the coupling between pairs of patch antennas has been examined. The improvement of the mutual coupling at the level of 10 dB has been obtained. One of the advantages of the demonstrated method is a possibility to perform the selective and direct metallization of the AlN ceramics surface without using any mask as opposed to photolithography. It greatly reduces the implementation time of the projected metamaterial structures.     

Effect of downscaling on the linearity range of a calibration curve in spectrofluorimetry

Interest in the microfluidic environment, owing to its unique physical properties, is increasing in much innovative chemical, biological, or medicinal research. The possibility of exploiting and using new phenomena makes the microscale a powerful tool to improve currently used macroscopic methods and approaches. Previously, we reported that an increase in the surface area to volume ratio of a measuring cell could provide a wider linear range for fluorescein (Kwapiszewski et al., Anal. Bioanal. Chem. 403:151–155, 2012). Here, we present a broader study in this field to confirm the assumptions we presented before. We studied fluorophores with a large and a small Stokes shift using a standard cuvette and fabricated microfluidic detection cells having different surface area to volume ratios. We analyzed the effect of different configurations of the detection cell on the measured fluorescence signal. We also took into consideration the effect of concentration on the emission spectrum, and the effect of the surface area to volume ratio on the limit of linearity of the response of the selected fluorophores. We observed that downscaling, leading to an increase in the probability of collisions between molecules and cell walls with no energy transfer, results in an increase in the limit of linearity of the calibration curve of fluorophores. The results obtained suggest that microfluidic systems can be an alternative to the currently used approaches for widening the linearity of a calibration curve. Therefore, microsystems can be useful for studies of optically dense samples and samples that should not be diluted.

Synthesis, structures, and electrochemistry of gold(III) ethylenediamine complexes and interactions with guanosine 5'-monophosphate

[Au(en)Cl(2)]Cl.2H(2)O, where en = ethylenediamine (1,2-diaminoethane), has been synthesized, and its structure has been solved for the first time by the single-crystal X-ray diffraction method. The complex has square-planar geometry about Au(III), and the anionic Cl- is located in the apical position and at a distance of 3.3033(10) A compared to 2.2811(9) and 2.2836(11) A for the coordinated Cl-. [Au(en)Cl2]Cl.2H2O belongs to the space group Pbca with a = 11.5610(15) A, b = 12.6399(17) A, c = 13.2156(17) A, alpha = beta = gamma = 90 degrees , and Z = 8. Bond lengths of Au-N are 2.03 A. [Au(en)Cl2]Cl.2H2O is less thermally stable than [Au(en)2]Cl3 because of the replacement of two Cl ligands by a second en ligand in the latter. Cyclic voltammetry shows that the formal potential of Au(III)/Au(0) becomes more negative in the series [AuCl4]-, [Au(en)Cl2]+, and [Au(en)2]3+. 1H, 13C, and 31P NMR reveal that in an aqueous solution [Au(en)Cl2]+ bonds to guanosine 5'-monophosphate, 5'-GMP (1:1 mole ratio), via N7, although the stability is not very high. NMR data also indicate that N7-O6 or N7-phosphate 5'-GMP chelation, as found in some gold(III) nucleotide complexes, is not present. The gold(III) complex undergoes hydrolysis at pH >2.5-3.0 and, therefore, N1 coordination to 5'-GMP is not observed. No direct coordination between 5'-GMP and [Au(en)2]Cl3 is observed.     

Effect of a high surface-to-volume ratio on fluorescence-based assays

In the work discussed in this paper, the effect of a high surface-to-volume ratio of a microfluidic detection cell on fluorescence quenching was studied. It was found that modification of the geometry of a microchannel can provide a wider linear range. This is a phenomenon which should be taken into consideration when microfluidic systems with fluorescence detection are developed. The dependence of the linear range for fluorescein on the surface-to-volume ratio was determined. Both fluorescence inner-filter effects and concentration self-quenching were taken into consideration. It was found that inner-filter effects have little effect on the extent of the linear range on the microscale.     

Pressure induced phase transitions of TTAB-micellar solutions studied by SANS and Raman spectroscopy

Using small angle neutron scattering in combination with optical Raman spectroscopy, phase transitions in the micellar system tetradecyl-trimethylammonium bromide (TTAB) have been investigated in a wide range of temperatures, pressures and surfactant concentrations. Allowing for the sluggish kinetics of crystallisation, the phase diagram in the p-T-c space could be determined that is dominated by a pronounced two-phase region of coexisting liquid and solid phases at elevated pressures.     

Entropy and Ergodicity of Boole-Type Transformations

We review some analytic, measure-theoretic and topological techniques for studying ergodicity and entropy of discrete dynamical systems, with a focus on Boole-type transformations and their generalizations. In particular, we present a new proof of the ergodicity of the 1-dimensional Boole map and prove that a certain 2-dimensional generalization is also ergodic. Moreover, we compute and demonstrate the equivalence of metric and topological entropies of the 1-dimensional Boole map employing “compactified”representations and well-known formulas. Several examples are included to illustrate the results. We also introduce new multidimensional Boole-type transformations invariant with respect to higher dimensional Lebesgue measures and investigate their ergodicity and metric and topological entropies.     

Transverse momentum distribution in Pomeron-Pomeron collisions at the CERN ISR

Proton-proton interactions which result in a central cluster of massM _x and two quasi-elastically scattered protons are generally described by Pomeron-Pomeron scattering. A study of this process at ISR energies with the Split Field Magnet detector is carried out in terms of transverse momentum behaviour for the centrally produced system of particles. The inclusivep _T distribution for central hadrons is measured up to 3 GeV/c. Forp _T <1.2 GeV/c, thep _T distribution is exponential. Using a subsample of exclusive events, this exponential shape is shown to originate from a phase-space-like decay ofM _x when convoluted with a transverse component of the pomeron momentum. In the highp _T range, the shape of thep _T distribution strongly depends on Feynman-x of the scattered protons in a way that can be described by hard parton scattering.