Lanthanide complexes with β-diketones and coumarin derivates: synthesis,thermal behaviour,optical and pharmacological properties and immobilisation

The paper presents the results of the synthesis of complexes of the type Eu(DBM)₃ and Eu(DBM)₃·Q (DBM-dibenzoylmethane, Q-1,10-phenantroline or 4,7-diphenyl-1,10-phenantroline) and of Tb- and Nd-complexes with the newly-synthesised coumarin derivates 3,3′-[(4-chlorphenyl)methylene)bis(4-hydroxy-2H-chromen-2-one), 3,3′-[(3,5-dimethoxy-4-hydroxy)methylene)bis(4-hydroxy-2H-chromen- 2-one), etc. Elemental and thermogravimetric analysis, IR, UV, NMR and fluorescence spectroscopy and X-ray analysis were applied for characterisation of the complexes. Some peculiarities of the synthetic procedures for both types of complexes were discussed and the influence of the synthetic approach, pH of the reaction medium, temperature of synthesis and drying of the complexes on the composition, stability and optical properties was reported. The immobilisation of the complexes in thin films based on sol-gel produced SiO₂ and on polymethylmethacrylate was studied. The optimal conditions for preparation of the matrices (composition of the starting system, temperature and time of sol aging, etc.) were recommended. The film morphology was evaluated by fluorescence, scanning electron and atomic force microscopy. The interaction of the lanthanide ions with the matrices and the influence of their nature, the effect of the in-situ polymerisation and other factors on photoluminescent excitation and emission spectra and excited state life-times of the complexes were followed. The effect of the second ligand on the photoluminescence properties of the immobilised diketonates was further elucidated. Processes involved in the thermal decomposition of the complexes and microcomposites produced on their base were proposed. Preliminary results on the pharmacological properties of the coumarin complexes reported showed unambiguously higher cytotoxicity of the Nd complex in comparison with that of the respective ligand.     

An overview of forestry journals in the period 2006–2010 as basis for ascertaining research trends

Articles published between January 1, 2006 and December 31, 2010 in 42 forestry journals (N = 16,258) were collected and, depending on their content and key words, classified in one of 22 sub-disciplines. Among the forestry sub-disciplines, the following are currently dominant: Mensuration and inventories, Forest management, Plant ecophysiology and Wood science. PCA ordination was used to visualize grouping tendencies and data separation. For each component, a number of characteristics contributed to the total variation, and significant importance was attached to those with the highest loading factors. The first component included Mensuration and inventories, Plant ecophysiology, Vegetation ecology and Forest management, as the highest loading factors. The second components comprised Sociological aspects, Plant ecophysiology, Wood science and Forest management. The most pronounced increase trend over the five-year period is noted for Genetics and breeding, Vegetation ecology, Fuels and energy, while the most pronounced decrease trend is visible in Forest health, Forest fire, Sociological aspects and Forest products. PCA suggests the existence of three groups of journals: the first group comprises Forest Ecology and Management and Canadian Journal of Forest Research, the dominating two, the second group comprises Annals of Forest Science, Plant Ecology, Tree Physiology and Trees-Structure and Function, while the rest of the journals belong to the third group. The Canadian Journal of Forest Research is the most diversified, while Tree Genetics and Genomes, Silvae Genetica and Tree-ring Research are narrowly specialized.     

Physical modification of polypropylene fibers used in construction

One of the applications of polypropylene fibers (PP) is in construction like reinforcement in concretes. Research on the use of PP fibers in silicate composites already has fairly long history. But there are some disadvantages, which must be eliminated. Observed, low affinity between the fibers and cement matrix is associated with nonpolar, hydrophobic, physical, and chemical inactive polyolefinic character of this polymer. The increase in adhesion of PP fibers to matrix could be achieved with the physical modification of PP fibers with inorganic additive. The most importance inorganic additive into concrete is silica fume. The aim of our paper is the presentation of the influence of modification on properties of PP fibers. There will be evaluated the optimization of composition (contents of nanoadditive and dispersant) of prepared PP fibers based on the mechanical and thermomechanical properties, the sorption moisture as well as on the macromorphological structure of PP surface.     

Blackberry seed extracts and isolated polyphenolic compounds showing protective effect on human lymphocytes DNA

The tentative identification of seed extracts from 3 cultivars of blackberry (blackberry seed extracts [BSEs]) constituents was performed by LC/UV/MS technique. The identified compounds belonged to ellagitannins, galic acid derivatives, and ellagic acid derivatives. Two ellagitannins, Lambertianin C and Sanguiniin H-6, and an ellagic acid derivative, 4-α-L-arabinofuranosylellagic acid, were isolated using semipreparative High-performance liquid chromatography. The structure elucidations were based on high resolution-mass spectrometry and nuclear magnetic resonance studies. The BSEs and 3 isolated pure compounds were tested for in vitro protective effect on chromosome aberrations in peripheral human lymphocytes using cytochalasin-B blocked micronucleus (MN) assay. The frequency of MN was scored in binucleated cells, and nuclear proliferation index was calculated. Among the tested extracts, the seeds of cv. Thornfree at concentration of 1 μg/mL exhibit the most prominent effect decreasing the frequency of MN by 62.4%, when compared with the controls cell cultures. Antioxidant potential of pure ellagitannins cannot explain the strong effect of BSEs. The assumption was that better antioxidant effect of BSEs result from synergistic effects of individual compounds contained in the extracts and/or some minor components possessed strong activity. PraCTICAL APPLICATION: Our results provide evidence of protective effects of BSEs and isolated pure compounds on cytogenetic damages in human lymphocytes. Thus, BSEs could exert beneficial effects in quite a few diseases, because many of the biological actions have been attributed to their antioxidant properties.     

Effects of high temperature drying in nitrogen atmosphere on mechanical and colour properties of Norway spruce

Heat treatment and drying processes of wood are always accompanied by material changes. These changes are partly caused by oxidative reactions. This study aims to compare high temperature drying in inert gas atmosphere with conventional kiln drying of spruce wood. The mechanical properties as well as colour changes were measured after drying. In general, higher compression strength was observed for samples dried at high temperatures in nitrogen atmosphere. However, tensile and bending strength proved no significant difference. Corresponding to the strength values increased stiffness values were also observed for the compression samples, whereas for tension and bending samples no significant effect was visible. Up to a temperature of approx. 125 °C discolouration is prevented by drying samples in nitrogen atmosphere.     

Evaluation of the effect of lichens on ceramic roofing tiles by scanning electron microscopy and energy-dispersive spectroscopy analyses

The effect of the actions of some lichens on the quality of ceramic roofing tiles was investigated in view of textural and microstructural changes considering their biocorrosion resistance. Two types (extruded and pressed) of the real ceramic roofing tiles aged 6 to 10 years, as well as the ceramic model systems formed with the additives of the specific chemical composition Cu-slag powder (10 wt%) and CuO powder (1 wt%), treated with various concentrations of oxalic acid (0.01 wt%, 0.1 wt%, and 4 wt%) were investigated. The thalli of lichen (Verrucaria nigrescens) growth on ceramic roofing tile were examined by scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). Investigation by SEM and EDS gave information regarding the ultrastructure characteristics of the thallus and the lichen-ceramic tile contact zone, allowing the observation of the hyphal penetration and filling up of the fissures and cracks by the lichens' hyphae. The CuO as the raw mixture additive changed the quality of the surface of the ceramic model systems as it has increased resistance to oxalic acid actions. The textural changes in the ceramic model systems and the formation of the identified destructive crystal phase, whewellite, were slowed down. The fundamental interactions between lichens and ceramic materials of the model systems have been identified as physico-chemical processes based on oxalic acid actions, which could cause ceramic matrix deterioration and consequently aging of ceramic roofing tile systems.     

Polymerization of aniline in the solutions of strong and weak acids: the evolution of infrared spectra and their interpretation using factor analysis

The progress of the oxidative polymerization of aniline with ammonium peroxydisulfate in an aqueous medium has been monitored in situ by attenuated total reflection Fourier transform infrared spectroscopy. The growth of polyaniline film at the crystal surface, as well as the changes proceeding in the surrounding aqueous medium, are reflected in the spectra. The evolution of the spectra during aniline polymerization in the presence of acetic or sulfuric acid was studied with the aim of understanding the influence of acidity on the observed morphology of the final polyaniline films, granular or nanotubes. The changes occurring during polymerization are discussed with the help of differential spectra. Several processes connected with the various stages of aniline oxidation, the evolution of film morphology, or protonation, were distinguished by using factor analysis applied to a large number of spectra obtained in the course of aniline polymerizations on the crystal.