Characterization of defects generated by di-and trivalent cations in the potassium-dihydrophosphate structure and their influence on growth kinetics and face morphology

Different types of defect sites generated by the impurities of divalent (M²⁺) and trivalent (M³⁺) metals in the structure of potassium dihydrophosphate KH₂PO₄ (KDP) were revealed by crystal-chemical analysis and computer simulation. These sites cause different deformations of the crystal matrix by generating different local strains, which enhance the inhibiting effect of impurity atoms adsorbed on the surface. This fact accounts for the different influence of di-and trivalent cations on the growth kinetics and face morphology of KDP crystals. The effect of the M³⁺ ions is associated primarily with their adsorption on the face surfaces, whereas the influence of the M²⁺ ions results from their insertion into the surface layer of the crystal.     

Complexes of Cu(I) and Pd(II) with (+)-camphor and (–)-cavrone thiosemicarbazones: Synthesis,structure, and cytotoxicity of the Pd(II) complex

CuLCl, CuL¹Cl, PdLCl₂, and PdL¹Cl₂ complexes [L and L¹ being (+)-camphor and (–)-carvone thiosemicarbazones, respectively] have been synthesized. The structure of binuclear [Pd₂L²²Cl₄] complex has been determined by means of X-ray diffraction. The L² ligand (dehydrogenated (–)-carvone thiosemicarbazone) is coordinated via the bridging S atom to two Pd atoms. The complexes of Cu(I) and Pd(II) presumably have polynuclear and binuclear structure, respectively. These facts are in good agreement with IR and NMR spectroscopy as well as mass spectrometry data which indicate the coordination of L and L¹ ligands via the S atom. The influence of L¹ and PdL¹Cl₂ on viability of the Hep2 cell line has been studied. The PdL¹Cl₂ complex is more cytotoxic than L¹ ligand.     

Molecular Mechanisms of Anticancer Activity of N-Glycosides of Indolocarbazoles LCS-1208 and LCS-1269

Novel indolocarbazole derivatives named LCS were synthesized by our research group. Two of them were selected as the most active anticancer agents in vivo. We studied the mechanisms of anticancer activity in accordance with the previously described effects of indolocarbazoles. Cytotoxicity was estimated by MTT assay. We analyzed LCS-DNA interactions by circular dichroism in cholesteric liquid crystals and fluorescent indicator displacement assay. The effect on the activity of topoisomerases I and II was studied by DNA relaxation assay. Expression of interferon signaling target genes was estimated by RT-PCR. Chromatin remodeling was analyzed–the effect on histone H1 localization and reactivation of epigenetically silenced genes. LCS-induced change in the expression of a wide gene set was counted by means of PCR array. Our study revealed the cytotoxic activity of the compounds against 11 cancer cell lines and it was higher than in immortalized cells. Both compounds bind DNA; binding constants were estimated—LCS-1208 demonstrated higher affinity than LCS-1269; it was shown that LCS-1208 intercalates into DNA that is typical for rebeccamycin derivatives. LCS-1208 also inhibits topoisomerases I and IIα. Being a strong intercalator and topoisomerase inhibitor, LCS-1208 upregulates the expression of interferon-induced genes. In view of LCSs binding to DNA we analyzed their influence on chromatin stability and revealed that LCS-1269 displaces histone H1. Our analysis of chromatin remodeling also included a wide set of epigenetic experiments in which LCS-1269 demonstrated complex epigenetic activity. Finally, we revealed that the antitumor effect of the compounds is based not only on binding to DNA and chromatin remodeling but also on alternative mechanisms. Both compounds induce expression changes in genes involved in neoplastic transformation and target genes of the signaling pathways in cancer cells. Despite of being structurally similar, each compound has unique biological activities. The effects of LCS-1208 are associated with intercalation. The mechanisms of LCS-1269 include influence on higher levels such as chromatin remodeling and epigenetic effects.     

Efficient calculation of the packing density of the crystal lattice of perovskite

The methodology of efficient macroscopic calculation of parameters of the cubic crystal lattice based on the use of the coefficient of structured packing of its elementary cell is considered. The possibility of precision theoretical determination of the numerical values of interatomic distances in crystals of the type under consideration is shown.     

Dependence of the adsorption and catalytic properties of a copper-platinum catalyst on the structure of metal particles and the composition of the catalyst surface

The kinetics of H₂ desorption from the surface of a copper-platinum catalyst deposited on silica gel ([1 wt % Pt + 0.15 wt % Cu]/SiO₂) and the kinetics of C₆H₁₂ dehydrogenation were studied. The effects of copper introduction in a platinum catalyst on the structural characteristics of platinum particles, the composition of their surface, and the effects of plasmochemical treatments on these parameters were studied by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The metal-H atom bond energies (E _Pt-H) and the catalytic activity were found to increase in the presence of Cu. This was explained by the formation of new hydrogen adsorption centers (due to the Cu^+δ adatoms) and catalytic centers composed of Cu^+δ adatoms and carbon atoms. The mean diameter of Pt particles (D) increased twofold. The microstresses (ɛ) in the particles increased after the catalyst was treated with glow discharge plasma in Ar and O₂ and with high-frequency plasma in H₂ (HF-H₂). The observed changes in the bond energy E _Pt-H and kinetic parameters were explained by the increase in microstresses in Pt particles.     

Uranyl orthovanadate of composition (UO2)3(VO4)2 · 4H2O: Synthesis and characterization

Uranyl orthovanadate of composition (UO₂)₃(VO₄)₂ · 4H₂O was prepared by heating uranovanadic acid HVUO₆ · 2H₂O under hydrothermal conditions at 200°C. X-ray fluorescence analysis, high-temperature X-ray diffraction, scanning calorimetry, and IR spectroscopy served to study dehydration and to determine the structure, X-ray diffraction, and spectroscopic characteristics of dehydration products.     

Chemical transformations of betulonic aldehyde

Chemical transformations of 3-oxolup-20(29)-en-28-al in oxidation, reduction, reductive amination, aldol crotonic condensation, cyclopropanation, Grignard, and Wittig reactions were investigated. The structure of reaction products was established by X-ray diffraction (XRD) analysis.     

Properties of a Fireproofing Formulation Based on Liquid Glass and Mechanically Activated Aluminum Oxide

Moistening of filler particles with binder, curing, and high-temperature synthesis were studied in a liquid-glass formulation based on aluminum oxide. Selected kinetic parameters of these processes were determined. The influence exerted by the phase composition and mechanical activation on the adhesion, yield of the synthesis product, and basic properties of the formulation were analyzed.