Volumen 7 (2014): Edición 2 (October 2014)

Sensitivity of contact spin density as well as electron density to the size of nucleus is investigated using the Gaussian model of nucleus and the point charge nucleus model. Scalar Infinite Order Two Component and scalar second order Douglas-Kroll-Hess quasirelativistic contact spin densities (spin densities at the nucleus) of Cu, Ag and Au atoms are considered. The non-relativistic contact spin densities and the valence s-orbital contact densities of Kramers restricted orbitals (Cu, Ag, Au atoms) are presented as well. The picture change error in the quasirelativistic calculations of spin densities is corrected by analytic means. Uncontracted triple-zeta UTZ+Ns basis sets are employed, where N is the number of additional tight s Gaussians. In addition, the impact of tight p and d Gaussians is briefly discussed.

The molecules of the title compound, C₁₁H₁₆NS·I, crystallize as single enantiomer with two stereogenic centre, their absolute configuration were confirmed by anomalous dispersion effects in diffraction measurements on the crystals. The conformation of the pyrrolidine ring is close to that of an envelope, with the flap atom N1 displaced by 0.661 (2) A from the plane of the oder remaining four atoms. The central six-membered ring of the indolizine moiety adopt a half-chair conformation with atom C5 displaced by -0.686 (2) Å from the plane of the oder remaining five atoms. The crystal structure of the title compound is stabilized by C-H···I···H-C hydrogen interactions.

This review focuses on sample preparation procedures used for chromatographic analysis of the most common organochlorinated pollutants and PAHs in water samples. The studied pollutants have a long persistence in environment, possible carcinogenic effects, and their application has been banned in many countries. The standard ISO procedures with the modern sample preparation procedures were compared in the term of recovery effectiveness for target analytes.

The continuous stirred-tank reactor with uncertain parameters was stabilized in the open-loop unstable steady state using the robust model predictive control. The gain matrices of the robust state-feedback controller were designed using the nominal system optimization and the quadratic parameter-dependent Lyapunov functions. The controller was verified by simulations using the non-linear model of the reactor and compared with the robust model predictive controller designed using the worst-case system optimization. The values of the quadratic cost function and the consumption of coolant were observed. Both robust model predictive controllers stabilized the reactor despite constrained control inputs and states. The robust model predictive control based on the nominal system optimization improved control responses and decreased the consumption of coolant.

As a part of our systematic study of copper(II) complexes in presence of biologically active ligands, we concluded to realize experiments with methyl- or methoxysalicylatocopper(II) complexes in presence of 2-aminomethylpyridine (ampy) ligand. This has resulted in four new complexes of the formula Cu(XSal)2(ampy) (where XSal are 3-MeSal⁻ = 3-methylsalicylate, 4-MeSal⁻ = 4-methylsalicylate, 5-MeSal⁻ = 5-methylsalicylate, or 4-MeOSal⁻ = 4-methoxylsalicylate anions). The synthesis, elemental analysis and spectral properties (EPR, electronic and infrared) are reported. The Cu(II) atom in all four complexes is probably coordinated by two nitrogen atom of the bidentate chelating ampy as well as monodentate and/or highly asymmetrically chelating salicylate anions. Based on the analyses it was concluded that the structure of these new compounds could be similar to [Cu(HCOO)₂(ampy)], or [Cu(CH₃COO)₂(ampy)] that are reported in the literature.

Glucosylceramide (GlcCer) is an essential glycosylated lipid found in organisms ranging from fungi to mammals. It is composed of a hydrophilic β-linked glucose and a hydrophobic ceramide, with a predominant content of sphingosine in mammals (d18:1). GlcCer is the precursor of a large scale of different glycosphingolipids. This cerebrozide is synthesized from uridine diphosphate-glucose and ceramide by a GlcCer synthase (UDP-glucose:ceramide glucosyltransferase; UGCG, EC 2.4.1.80). GlcCer-based sphingolipids have been identified as important mediators of a variety of cellular functions and their disequilibrium leads to pathological process development and may induce several diseases progression. Therefore, design of UGCG inhibitor represents an important topic for pharmaceutical research. In this paper, we aimed to study effects of newly synthesized derivatives of (±)-threo-1-phenyl-2-palmitoylamino-3-morpholino-1-propanol (PPMP, known UGCG inhibitor) on: i) activity of UGCG in vitro; ii) thymocytes viability; iii) calcium transport through plasma membrane of thymocytes; iv) induction of apoptosis and autophagy in thymocytes. Thymocytes were isolated from thymus of three to seven weeks old mice (ICR strain). The key factors influencing the effect of PPMP analogues were their concentration, chemical structure and incubation time. Derivatives were able to change Ca²⁺ transport already after 15 min of cultivation, but their effects on cell viability were manifested at least after 12 h of cultivation. Four from fifteen studied compounds affected UGCG activity after four hour lasting cultivation, - but without correlation with data relating to effects on calcium transport and/or cell viability. Most potent UGCG inhibitor was chosen and applied for induction of apoptosis and autophagy in thymocytes. This inhibitor induced typical DNA fragmentation and upregulation of LC3B protein as autophagy marker, after 2 h and 4 h cultivation, respectively.

New electrochemical method for determination of Nordiazepam (NDZ) at meniscus modified silver solid amalgam electrode (m-AgSAE) was developed utilizing differential pulse voltammetry (DPV). The pH effect on the current response of NDZ was studied in the mixture of Britton-Robinson buffer (BR) and methanol (9:1) with optimum pH value of 10. The calibration dependences were examined under the optimal conditions and linearity in the range from 2 × 10⁻⁶ to 1 × 10⁻⁴ mol L⁻¹ with limit of quantification of 1.7 × 10⁻⁶ mol L⁻¹ were accomplished.

Genomics is a branch of bioanalytical chemistry characterized as the study of the genome structure and function. Genome represents the complete set of chromosomal and extrachromosomal genes of an organism, a cell, an organelle or a virus. There are at least five from eight species of herpesviruses commonly widespread among humans, Herpes simplex virus type 1 and 2, Varicella zoster virus, Epstein-Barr virus and Cytomegalovirus. Human gammaherpesviruses can cause serious diseases including B-cell lymphoma and Kaposi’s sarcoma. Diagnostics and study of the herpesviruses is directly dependent on the development of modern analytical methods able to detect and determine the presence and evolution of herpesviral particles/ genomes. Diagnostics and genomic characterization of human herpesvirus species is based on bioanalytical methods such as polymerase chain reaction (PCR), DNA sequencing, gel electrophoresis, blotting and others. The progress in analytical approaches in the herpesvirus genomics is reviewed in this article.

The mercury content in hairs was determined in the framework of the European funded projects COPHES and DEMOCOPHES to test the feasibility of an EU-HBM (Human Biomonitoring) approach generating comparable data. The aim of the Slovak participation in DEMOCOPHES was to obtain and contribute the Slovak data to the harmonization of Human Biomonitoring. Pre-analytical and analytical phase for mercury in hair measurements and activities developed for the harmonization analysis within COPHES/ DEMOCOPHES projects were conducted under a strict quality assurance program (QA/QC). Total mercury in hair was determined by thermal decomposition-gold amalgamation atomic absorption spectroscopy (AMA- 254 Advanced Mercury Analyzer.) Two interlaboratory comparison investigations (ICIs) and two external quality assessment schemes (EQUAS) were conducted before the beginning of the COPHES/DEMOCOPHES projects. The laboratory successfully completed both ICIs and EQUAS schemes and was allowed to analyze all DEMOCOPHES samples of the Slovak Republic. In summary, 129 mother-child pairs were recruited to pilot study of DEMOCOPHES in Slovakia from two different locations representing urban and rural environment. The analyzed data from Slovakia showed relationship between frequency of fish meals consumption (especially sea fish and sea food products) and mercury concentrations in hair of mothers and children. The exposure levels for a sampled population in Slovakia (children 0.092 (0.080-0.106) [μg.g^-1], mother 0.130 (0.113-0.148) [μg.g^-1]) are below the EU level (children 0.145 (0.139-0.151) [μg.g^-1], mother 0.225 (0.216-0.234) [μg.g^-1]) up to an order of magnitude lower than the limit medically important (FAO/WHO health-based guidance value of 2.3 μg.g^-1 JECFA - Joint FAO/WHO Expert Committee on Food Additives).

A chemical microsolvation model for solution phase bond dissociation enthalpy (BDE) evaluation by means of molecular dynamics is presented. In this simple model, the primary solvent effect on the BDE values was estimated by placing of five water molecules nearby the studied functional groups evenly. Furthermore, the secondary solvent effect was reflected using the conductor like screening model (COSMO). From the quantum-chemical point of view, the molecular dynamics simulations based on the B3LYP functional in rather small basis set were performed. Despite of the constitutional limitations of the proposed model, the obtained O-H and N-H BDE values in phenol (363 kJ mol^-1) and aniline (369 kJ mol^-1) are in good agreement with the experimental solution phase data.

In order to separate liquid mixtures, common distillation is not always suitable, especially if relative volatility of the mixture components is close to or equals unity, thus avoiding separation based on the vapor enrichment by more volatile component. To overcome this limitation of distillation, several alternatives were suggested including pressure swing and extraction distillation. Another, principally different, separation method used for the liquid mixtures separation is liquid-liquid extraction. Separation efficiency of this method is closely related to the basic extraction solvent characteristics, capacity and selectivity. In order to minimize costs connected with extraction, new extraction solvents are developed, among which ionic liquids show high potential due to their tunable properties. Here, efficiency of traditional extraction solvent, benzene, was compared to that of tetradecyltrihexylphosphonium bis(trifluoromethylsulfonyl)imide ionic liquid in separation of ethanol from its aqueous solution. The comparison was assessed on the base of results of a counter-current extractor simulation. Further, some economic aspects of this separation procedure were discussed. Optimum consumption of extraction solvent was identified taking into account alcohol-to-water molar (mass) ratio in the final extract as optimization criterion.