Biogeographical patterns and determinants of invasion by forest pathogens in Europe.

A large database of invasive forest pathogens (IFPs) was developed to investigate the patterns and determinants of invasion in Europe. Detailed taxonomic and biological information on the invasive species was combined with country-specific data on land use, climate, and the time since invasion to identify the determinants of invasiveness, and to differentiate the class of environments which share territorial and climate features associated with a susceptibility to invasion. IFPs increased exponentially in the last four decades. Until 1919, IFPs already present moved across Europe. Then, new IFPs were introduced mainly from North America, and recently from Asia. Hybrid pathogens also appeared. Countries with a wider range of environments, higher human impact or international trade hosted more IFPs. Rainfall influenced the diffusion rates. Environmental conditions of the new and original ranges and systematic and ecological attributes affected invasiveness. Further spread of established IFPs is expected in countries that have experienced commercial isolation in the recent past. Densely populated countries with high environmental diversity may be the weakest links in attempts to prevent new arrivals. Tight coordination of actions against new arrivals is needed. Eradication seems impossible, and prevention seems the only reliable measure, although this will be difficult in the face of global mobility.

Microstructural characterization of nanocrystalline gold particles supported on CoCr2O4.

This work presents results of high-resolution transmission electron microscope investigations of microstructure evolution of Au/CoCr(2)O(4) catalyst subjected to various chemical treatments (reduction in hydrogen, reaction of propane oxidation and reaction of CO oxidation). Crystallites of CoCr(2)O(4) support have octahedral or truncated octahedral shape and exhibit well-developed faces, mostly (111). No change in the support morphology was noticed in catalyst samples after various chemical treatments. Small (approximately 8 nm) nanocrystals of gold supported on crystalline CoCr(2)O(4) were observed for the fresh sample. The nanoparticles grow at the surface of CoCr(2)O(4) as thin, disk-like crystallites, in the preferred (111)Au parallel(111)CoCr(2)O(4) epitaxial orientation. Further treatment in hydrogen and in reaction conditions (CO and propane oxidation) did not change noticeably the size of Au particles, but modified slightly their shape. A main reason why Au particles retain small size despite heat treatment is their epitaxial contact with the CoCr(2)O(4) support established during the catalyst preparation.

Structural characterization of nano-sized Ce 0.5 Ln 0.5 O 1.75 (Ln = Yb, Lu) mixed oxides.

This work presents results of HRTEM and XRD studies on microstructure of ceria-based mixed oxides subjected to high-temperature heat treatment in air. Nano-sized (4-5 nm) crystallites of Ce(0.5)Ln(0.5)O(1.75) oxides (Ln = Yb, Lu) with narrow size distribution were prepared by a microemulsion method (W/O). Presence of an intermediate cubic phase, with oxygen vacancy ordering, was found for the Ce(0.5)Ln(0.5)O(1.75) mixed oxides. A simple model of the intermediate phase has been proposed and tested.

Functional up-converting SrTiO3:Er(3+)/Yb(3+) nanoparticles: structural features, particle size, colour tuning and in vitro RBC cytotoxicity.

SrTiO3 nanoparticles co-doped with a broad concentration range of Er(3+) and Yb(3+) ions were fabricated using the citric route as a function of annealing temperatures of 500-1000 °C. The effect of a broad co-dopant concentration range and sintering temperature on structural and up-conversion properties was investigated in detail by X-ray diffraction techniques and optical spectroscopy. The TEM technique was used to estimate the mean particle size, which was around 30 nm for the inorganic product annealed at 600 °C. Up-conversion emission color tuning was achieved by particle size control. Power dependence of the green and red emissions was found to be a result of temperature determination in the operating range of SrTiO3 nanoparticles and a candidate for the fast and local microscopic heating and heat release induced by IR irradiation. The color changed from white-red-yellow-green upon an increase of sintering temperature, inducing changes in the surface-to-volume ratio and the number of optically active ions in particle surface regions. The cytotoxic activity of nanoparticles on human red blood cells was investigated, showing no harmful effects up to a particle concentration of 0.1 mg ml(-1). The cytotoxic response of a colloidal suspension of nanoparticles to RBC cells was connected with the strong affinity of SrTiO3 particles to the cell membranes, blocking the transport of important biological solutes.

A new approach in the synthesis of La(1-x)Gd(x)FeO3 perovskite nanoparticles--structural and magnetic characterization.

A series of highly crystalline orthoferrite nanoparticles (type La(1-x)Gd(x)FeO3, where x = 0 to 1) were prepared using the self-combustion method. Extensive studies including X-ray diffraction, Rietveld refinement and Fourier transform infrared spectroscopy as well as Raman spectroscopy confirmed the orthorhombic space group Pnma of the obtained materials. The calculated average grain size for powders is in the range of 30 to 80 nm. Magnetic characterization of the La(1-x)Gd(x)FeO3 series, performed at 1.72 K, indicated an antiferromagnetic state characterized by some canting of iron magnetic moments, in good agreement with the data reported for similar fine-particle systems.

Synthesis, antimicrobial, and alkylating properties of 3-phosphonic derivatives of chromone.

Dimethyl 2,6-dimethyl-4-oxo-4H-chromen-3-yl-phosphonate (1a) and dimethyl 6-methyl-2-phenyl-4-oxo-4H-chromen-3-yl-phosphonate (1b) were synthesized and reacted with primary aliphatic amines to yield title compounds 4-6. Their antibacterial properties against Gram-positive and Gram-negative bacteria strains were tested by the MIC method. Four of seventeen tested compounds (1d, 3, 4a, and 4b) exhibit detectable activity against S. aureus. Some representative examples of newly synthesized compounds were tested for their alkylating properties in vitro in the Preussmann test. Compounds 1a, 1c, 1d, 3, 5d, and 6a possess highly alkylating activity toward standard derivative 4-(4'-nitrobenzyl)pyridine (NBP).

Antioxidant activity of ethanolic extracts of amaranth seeds.

Antioxidant activity of ethanolic extracts obtained from two amaranth species was evaluated in a beta-carotene-linoleic acid model system. The addition of amaranth extracts in the range of 0.01-0.1% inhibited degradation of a beta-carotene in a model emulsion during incubation at 60 degrees C; 0.05% addition of amaranth seeds extract was proposed as practically applicable. The total content of phenolic compounds was estimated by the Folin-Ciocalteu method and ranged from 39.17 mg/100 g of Amaranthus caudatus to 56.22 mg/100 g of A. paniculatus seeds. Free phenolic acids contained in ethanolic extracts of amaranth seeds were purified and isolated by solid-phase extraction (SPE) and identified by reversed-phase high-performance liquid chromatography (RP-HPLC). The technique involved gave a good separation of the free phenolic acids in the amaranth seeds. Significant differences in phenolic acids profiles of both amaranth species were observed.

trans-Diaquatetrakis(3,5-dimethylpyrazole-N2)nickel(II) dichloride.

The X-ray structure analysis of [Ni(C(5)H(8)N(2))(4)(H(2)O)(2)]Cl(2) was undertaken to elucidate the geometry around the Ni(2+) ion. The molecule lies on a twofold axis which runs through the O-Ni-O atoms. The geometry around the Ni(2+) ion is best described as slightly distorted tetragonal bipyramidal.