Band 61, Heft 4

Gold glyconanoparticles as elements of the nanoworld belong to a group of particles with diameters not exceeding 100 nm. This size scale makes them conformable to common biomolecules. A gold glyconanoparticle consists of three different parts: the gold core, the linkers, and saccharide ligands. The glycocalyx-like surface of these particles mimics the presentation of carbohydrate epitopes of cell surface glycoconjugates. As a consequence, gold glyconanoparticles provide inimitable tools for probing and manipulating the mechanisms of biological processes based on carbohydrate interactions. Each component of the gold glyconanoparticle has a profound effect on the nanoparticle’s properties. Therefore, in this review, elucidation of the overall behavior and properties of gold glyconanoparticles is based on a step by step (component by component) description of the system.

Organophosphorus pesticides parathion, chlorpyrifos, and malathion inhibit the enzyme acetylcholinesterase (AChE; EC 3.1.1.7) via phosphorylation of its active site. AChE reactivators and anticholinergics are compounds used as antidotes in the case of intoxication by these AChE inhibitors. In this work, chlorpyrifos, a representative member of this pesticide family, was used to inhibit the AChE activity of rat brain. The effect of twenty-one structurally different AChE reactivators was tested in vitro and subsequently, the relationship between their chemical structure and biological activity was outlined.

Low-density polyethylene (LDPE), polypropylene (PP), and their mixture in the mass ratio of 1: 1 (LDPE/PP) were thermally decomposed in a batch reactor at 450°C. The formed gaseous and oil/wax products were separated and analyzed by gas chromatography. The oils/waxes underwent both atmospheric and vacuum distillation. Densities, molar masses and bromine numbers of liquid distillates and distillation residues were determined. The first distillate fraction from the thermally decomposed LDPE contained mostly linear alkanes and alk-1-enes ranging from C6 to C13 (boiling point up to 180°C). The second distillate fraction was composed mostly of hydrocarbons C11 to C22 (boiling point up to 330°C). 2,4-Dimethylhept-1-ene was the major component of the first distillate fraction obtained from the product of PP decomposition, while in the 2nd distillate fraction it was 2,4,6,8-tetramethylundec-1-ene. The yields of some gaseous or liquid hydrocarbons obtained by distillation from thermally degraded LDPE/PP differed from the values corresponding to the decomposition of individual plastics due to the mutual influence of polyalkenes during their thermal cracking. Similarly, the yields of propene and methylpropene in the gaseous phase were higher in the case of mixture. Whereas the content of C9 to C17 alkanes and alkenes in the distillates separated from the liquid mixture obtained by the decomposition of LDPE/PP decreased, the formation of 2,4,6,8,10,12-hexamethylpentadec-1-ene remained unchanged. The corresponding mechanisms of thermal cracking were discussed.

The modified BCR three-step sequential extraction procedure has been applied to homogenized urban dust samples and to simulated air filters loaded with the prepared urban dust via the wet deposition procedure. This work has been focused on comparative study of the distribution of trace elements in both samples and evaluation of the factors influencing the reliability of results with respect to the proposed extraction procedure. Extracted chemical fractions were analyzed by ICP-OES and GFAAS depending on the concentration levels of investigated trace elements As, Cd, Cr, Mn, Ni, and Pb, selected according to their adverse effect on the human health. Statistically evaluated results indicate significant differences between the extracted portions of analytes in urban dust and simulated air filters, where the mobility of some analytes in simulated air filters was higher than that in urban dust samples. The impact of surfactant Triton X-100 (0.05 vol. %) on the extraction procedure was also investigated.

The effects of lime, limestone, and zeolite addition on the availability of As, Cd, Pb, and Zn in three contaminated soils were investigated in a pot experiment after four vegetation periods of spring wheat, spring barley, and oat. The results showed different responses of extractable element portions to soil amendment when 0.01 mol dm−3 aqueous CaCl2 was applied as a soil extraction agent. Substantial differences were evident among the investigated elements as well as among the individual soil treatments. Except natural zeolite, the ability of ameliorative materials to redistribute cadmium and zinc from a soil solution into less mobile but labile soil fractions was observed. The lead availability was less affected and the extractability of arsenic even increased in some of the treated pots. Moreover, the availability of arsenic was more affected by different characteristics of experimental soils than by individual soil treatments. It was found that these treatments can be applied neither for multicontaminated nor for all the soil types. The soil treatments had a lower effect on the less mobile soil fractions.

The effect of γ-irradiation on trichromatic color values L*, a*, and b* was determined in black pepper, oregano, and allspice samples irradiated at average doses from 5 kGy to 30 kGy. Trichromatic values a* measured in methanol extracts of treated spices immediately after the irradiation process were significantly changed, but the subsequent storage of allspice and oregano caused much more distinctive alteration of these color values than the irradiation itself. Additionally, the differences in redness between the reference (non-irradiated) allspice and oregano samples and samples treated by γ-radiation gradually disappeared during the storage period. On the contrary, the post-irradiation storage of black pepper samples did not reveal any changes of a* values.

A new symmetrical vicinal dioxime, N,N′-bis-{4-[[(2-hydroxyphenyl)methylene]hydrazinecarbonyl]phenyl}diaminoglyoxime (LH4), was prepared by reacting anti-dichloroglyoxime with salicylaldehyde 4-aminobenzoylhydrazone. The reaction of ligand with Ni2+ salts gave mono-and homopentanuclear complexes, [Ni(LH3)2] and [Ni5(LH)2X2]. Furthermore, heteropentanuclear complexes of dioxime ligand, [Cu4Ni(LH)2X4], were prepared by the reaction of [Ni(LH3)2)] with Cu2+ salt and a monodentate ligand (X = SCN−, CN−, or N3−). The structures of both the new symmetrical vicinal dioxime and its complexes were identified by elemental analyses, IR, 1H NMR, UV-VIS spectra, and magnetic susceptibility. The elemental analyses and spectral data indicate that the hydrazone side of ligand acts as a O,N,O′ tridentate and the fourth position is occupied with monodentate anion such as SCN−, CN−, N3−.

Tetrabromo-p-benzoquinone reacted with excess aromatic amines to give 2,5-dirylamino-3,6-dibromo-p-benzoquinones. The latter molecules on heating with sodium sulfide in alcohol in the presence of air gave triphenodithiazinediones. Heating with copper powder in nitrobenzene transformed these compounds into the respective indolocarbazolediones. Comparative antimicrobial and antifungal activities of the studied compounds were determined and discussed.

Dielectric relaxation measurements of butyl acrylate—alcohol mixtures at different concentrations and temperatures within the frequency range of 10 MHz to 10 GHz have been carried out using time domain reflectometry. Parameters such as the static permittivity, dielectric relaxation time, the Kirkwood correlation factor, the excess inverse relaxation time, and thermodynamic functions were determined and discussed to yield information on the molecular structure and dynamics of the mixture. The value of the dielectric properties decreases with increasing butyl acrylate concentration in alcohol and systematically varies with the length of alcohol alkyl chain. Negative values of the excess inverse relaxation time found for all concentrations and at all temperatures studied may indicate that the effective dipoles rotate slowly.

The geometries of the most stable isomers of gold telluride systems AuTe, Au2Te, and AuTe2 are determined using the MP2 method. The aspect of gold—telluride interaction, the electron correlation, and relativistic effects on geometry and stability are investigated at the MP2 and CCSD(T) theoretical levels. The results show that the electron correlation and relativistic effects are responsible not only for gold—gold attraction but also for additional gold—telluride interaction. The gold—telluride interaction is strong enough to modify the known pattern of bare gold clusters. Both effects are essential for determining the geometry and relative stability of this type of systems.

Theoretical study on the binding affinities of dehydrotetrapyrido[20] annulene to the alkene and aromatic molecules was performed using the AM1 and DFT methods. It indicated that the host possesses the ability to bind the above molecules since the binding energies of the complexes were negative. The complexes were stabilized via the hydrogen bonding, static effect, and π — π stacking interaction between the host and guest molecules. Based on the B3LYP/3-21G optimized geometries, the electronic, IR, and NMR spectra were calculated using the INDO/CIS, AM1, and B3LYP/3-21G methods, respectively. Due to the hydrogen bonding, the first absorption maxima in the electronic spectra of studied complexes were blue-shifted, whereas the main IR frequencies for some of the complexes were red-shifted. At the same time, the chemical shifts of carbon atoms forming the bonds in the complexes were lower, compared to those of the host.

Two methods for determination of lipid peroxidation (LPX) products in rat brain homogenates were compared. The thiobarbituric acid (TBA) test and HPLC assay for analysis of malondialdehyde (MDA) were applied. Rat brain homogenate dissolved in tris(hydroxymethyl)aminomethane hydrochloride (Tris-HCl) was mixed with TBA and H3PO4 and heated at 100°C to form colored complex that was extracted into butanol. No significant differences were found between the contents of TBA-reacting substances and their amount deduced from the MDA-TBA analysis. The presented results show that LPX products in brain homogenates can be determined without interferences also by the TBA test. Moreover, a survey of various methods used for the sample preparation before analysis of LPX products originating from different brain areas was made and compared with the obtained results.

A new binary chiral selector system effective for the enantioselective extraction of racemic mandelic acid is presented. While L-dipentyl tartrate and β-cyclodextrin had a very low enantioselectivity as single selectors, a preferential extraction of D-mandelic acid to the organic phase was found in the binary selector system. Using decanol as organic solvent and pH of a phoshate buffer equal to 2.3, the distribution coefficients of D-and L-mandelic acids as high as 14.9 and 7.0, respectively, and the enantioselectivity value of 2.1 were found at optimum concentration of β-cyclodextrin.

The thermal decomposition of cobalt acetate tetrahydrate (Co(CH3COO)2 · 4H2O) has been studied via thermogravimetric (TG) analysis, in situ X-ray powder diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The results of TG and XRD showed that the parent salt melted and then the dissolved crystalline water was vaporized in two steps. The dehydration process was followed by a major step concerning the decomposition of the acetate group, leading to basic acetate as an intermediate, which then produced CoO and Co in N2 and H2 atmosphere, respectively. Three decomposition intermediates Co(CH3COO)2 · 0.5H2O, Co(CH3COO)2, and Co(OH)(CH3COO) were presumed. In situ XRD experiments revealed that the intermediate basic acetate was poorly crystallized or even amorphous. Evolved gases analysis indicated that the volatile products of acetate decomposition were water vapor, acetic acid, ethylenone, acetone, and CO2. A detailed thermal decomposition mechanism of Co(CH3COO)2 · 4H2O was discussed.

An efficient synthesis of 3,4-dihydropyrimidin-2-(1H)-one derivatives by one-pot three-component condensation reaction between an alkyl or aryl aldehyde, a 1,3-dicarbonyl compound, and urea or thiourea in the presence of catalytic amount of bromodimethylsulfonium bromide has been developed. The condensation product was obtained in excellent yields in refluxing ethanol and easily separated from the reaction mixture and purified.