Platinum(II) complexes with thiourea derivatives containing oxygen,sulfur or selenium in a heterocyclic ring: computational studies and cytotoxic properties

Platinum(II) complexes with 1-(2-oxolanylmethyl)-2-thiourea, 1-(2-thiolanylmethyl)-2-thiourea and 1-(2-selenolanylmethyl)-2-thiourea were synthesized in order to compare their cytotoxic activities with those of the free thioureas. Their equilibrium geometries and bonding energies in the gas phase and in solution were calculated using density functional theory at the MPW1PW/LanL2DZ level. The IR spectra of the complexes and their free ligands were compared. Stability of the complexes in 0.9% saline aqueous solution was tested by means of HPLC. The cytotoxic activities of the species against five human cell lines were evaluated, as well as the antimicrobial activities against twelve bacterial strains.     

Bands with a small number of ternary term functions

Bands with at most 9 essentially ternary term functions are characterized in this paper. May 5, 1999     

Studies on the Use of Commercial Capillary Gas Chromatographic Columns as Diffusion Denuders

The possibility of using a piece of gas chromatographic capillary column as a tubular denuder for isolation and enrichment of organic pollutants present in air was studied. The partition coefficients (K_fs) of typical organic pollutants (benzene, chlorobenzene, toluene) between the gaseous phase and the denuder sorption layer were determined and effects of analyte concentration in the gaseous phase and gas flow rate on partitioning were studied. The partition coefficients were found to be constant in the studied range of concentration and gaseous mixture flow rate. A piece of a capillary column coated with polydimethylosiloxane can be used as a tubular denuder.     

Projection representable relations on Menger (2, n)-semigroups

Abstract characterizations of relations of nonempty intersection, inclusion end equality of domains for partial n-place functions are presented. Representations of Menger (2, n)-semigroups by partial n-place functions closed with respect to these relations are investigated.     

TG study on real role of active carbon support in propane dehydrogenation with CO2

Active carbon was used as a support for chromium(III) oxide phase. The synthesized materials appeared to be very active catalysts of the propane dehydrogenation in the presence of CO₂. An influence of the Cr content on the catalytic activity and selectivity was observed. The best results were achieved over the sample containing about 5 wt.% of Cr. A negative effect of activity decay with time-on-stream was found. The reasons of the observed deactivation were explained using the thermal analysis method. A behavior of the fresh and used samples was tested in a temperature range of 25–1000 °C in different atmospheres (inert gas, air or CO₂). It was found that the catalytic runs resulted in a partial decomposition of surface O-containing groups, which together with CrO_x species play a role of active centers. Moreover, a formation of inactive carbonaceous deposit on the catalyst surface was observed.     

High-spin rotational bands and pairing reduction in 166Hf

Rotational properties of the ¹⁶⁶Hf nucleus have been studied by in-beam spectroscopic methods using the ¹⁵⁰Sm(²⁰Ne, 4n)¹⁶⁶Hf reaction. The ground band was observed up to the I^π = 18⁺ level, the s-band from the I^π = 12⁺ up to I^π = 22⁺ level; in addition two side bands were found. The results are interpreted in terms of the pairing-self-consistent Hartree-Fock-Bogolyubov cranking model. Quantitative agreement between theory and experiment is obtained for the crossing of the ground band and s-band. The calculations predict a reduction of about 50 % in the neutron pairing energy gap of yrast states in the crossing region. The kinematical ($\text{I}$⁽¹⁾) and dynamical ($\text{I}$⁽²⁾) moments of inertia are analysed.     

Critical frequency in nuclear chiral rotation

Self-consistent solutions for the so-called planar and chiral rotational bands in 132La are obtained for the first time within the Skyrme-Hartree-Fock cranking approach. It is suggested that the chiral rotation cannot exist below a certain critical frequency which under the approximations used is estimated as Planck's omega(crit) approximately 0.5-0.6 MeV. However, the exact values of Planck's omega(crit) may vary, to an extent, depending on the microscopic model used, in particular, through the pairing correlations and/or calculated equilibrium deformations. The existence of the critical frequency is explained in terms of a simple classical model of two gyroscopes coupled to a triaxial rigid body.