Vitellogenin Underwent Subfunctionalization to Acquire Caste and Behavioral Specific Expression in the Harvester Ant Pogonomyrmex barbatus

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Predictive Markers of Honey Bee Colony Collapse

Across the Northern hemisphere, managed honey bee colonies, Apis mellifera, are currently affected by abrupt depopulation during winter and many factors are suspected to be involved, either alone or in combination. Parasites and pathogens are considered as principal actors, in particular the ectoparasitic mite Varroa destructor, associated viruses and the microsporidian Nosema ceranae. Here we used long term monitoring of colonies and screening for eleven disease agents and genes involved in bee immunity and physiology to identify predictive markers of honeybee colony losses during winter. The data show that DWV, Nosema ceranae, Varroa destructor and Vitellogenin can be predictive markers for winter colony losses, but their predictive power strongly depends on the season. In particular, the data support that V. destructor is a key player for losses, arguably in line with its specific impact on the health of individual bees and colonies

Influence of Cr on structural and optical properties of TiO2:Cr nanopowders prepared by flame spray synthesis

Influence of chromium incorporation on structural and optical properties of titanium dioxide nanopowders obtained by flame spray synthesis, FSS is studied by means of: X-ray diffraction, XRD; Raman spectroscopy; transmission electron spectroscopy, TEM; photoelectron spectroscopy, XPS and optical spectrophotometry over the ultraviolet, UV and visible range of the light spectrum from 250 nm to 2200 nm. The specific surface area, SSA, of the powders has been adjusted from 48 m2/g for TiO2 + 0.1at.% Cr to 177 m2/g for TiO2 + 15 at.% Cr which is accompanied by a decrease in the anatase grain size from 21 nm to 5 nm. The anatase-to-rutile ratio changes with Cr3+ concentration but there is no evidence of precipitation of chromium oxides or chromium titanates. Incorporation of Cr3+ into TiO2 lattice, as proved by XPS, is found to affect the electronic structure of TiO2, as indicated by the optical spectrophotometry. The impurity band is formed within the forbidden band gap of titanium dioxide which results in the additional absorption within the visible range of the light spectrum. The general aim of this work is to improve the visible light absorption and hence the efficiency of photocatalytic decomposition of organic contaminants

Chemical composition, crystallographic structure and impedance spectroscopy of titanium oxynitride TiNxOy thin films

Titanium oxynitride TiNxOy thin films have been deposited by DC-pulsed magnetron sputtering from Ti target in the Ar + N2 + O2 reactive atmosphere controlled by plasma emission spectroscopy. Correlation between chemical composition and crystallographic structure of thin films has been determined and presented in the form of the pseudo-equilibrium ternary phase diagram. The atomic N/Ti and O/Ti ratios have been derived from Rutherford backscattering (RBS) measurements. X-ray diffraction at grazing incidence has revealed formation of defective TiN-TiO solid solutions. The surface roughness estimated from atomic force microscopy (AFM) surface images decreases with increasing oxygen content in the films, in accordance with the progressive sample amorphisation. Impedance spectroscopy measurements indicate that the electrical conductivity changes its character from metallic to semiconducting with increasing oxygen content in TiNxOy thin films