Interactive effects of age and gender on levels of toxic and potentially toxic metals in children hair in different urban environments

Children growth and development may be affected by metal exposure. The objective of the present study was to investigate the interactive effects of age and gender on children hair toxic metal levels in urban environment of two Russian cities. A total of 2021 children living in Moscow and Novosibirsk aged 1–18 years old were examined. Hair Al, As, Cd, Hg, Ni, Pb and Sn levels were assessed using inductively-coupled plasma mass-spectrometry in dynamic reaction cell mode. Children from Novosibirsk were characterised by higher hair Al (37%), As (385%), Cd (127%), Hg (11%), Ni (23%), Pb (72%) and Sn (25%) in comparison to Moscow values. In the general cohort, boys had higher Al (13%), As (51%), Cd (65%), Pb (63%) and Sn (18%) levels, whereas hair Ni was higher in girls (17%). Further analysis demonstrated age-specific gender differences. In particular, only hair Ni and Cd levels were higher in male toddlers and pre-schoolers from Novosibirsk as compared to females. No gender difference was detected in Moscow. Maximal gender differences in hair metal levels were detected in adolescents for both locations. International Union of Pure and Applied Chemistry (IUPAC) reference values for all groups were also calculated. The overall reference limits for the studied children population were Al (1.335–3.340 µg/g), As (0.021–0.384 µg/g), Cd (0.000–1.389 µg/g), Hg (0.024–0.722 µg/g), Ni (0.076–0.701 µg/g), Pb (0.050–1.490 µg/g) and Sn (0.070–1.026 µg/g). Two-way ANOVA demonstrated significant effects of age, gender and age*gender interaction on hair metals in both cities. At the same time, the age-specific changes in hair metal content were more expressed in children from Novosibirsk, being exposed to higher metal pollution. The obtained data demonstrate that age, gender as well as the particular rate of pollution in each location should be taken into account during interpretation of hair test results.     

Charge transfer between quasi-zero-dimensional nanostructures

In the present paper, we show the main features of the theoretical formula allowing us to understand the irreversible transfer of electrons or holes, as it may be observed in some electrically conducting (conjugated) polymers. The formula reported here is derived with the use of the nonequilibrium quantum transport theory. The key role in the formula is played by the electron–phonon interaction which is included in an approximation going beyond the limits of the finite order of the perturbation calculation. The transfer formula is developed for a simple model of the stacked conjugated polymer, which is represented here by two interacting quantum dots. The numerical calculations show the dependence of the charge carrier mobility on the charge carrier concentration and on the lattice temperature. A comparison with organic field-effect transistor experiments and with molecular-scale modeling on conjugated polymers is promising.     

Photophysical properties and photodynamic activity of 13,15-N-methoxy-cycloimide chlorin p6 methyl ester in micellar surfactant solutions

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Structural study of the MO–Nd2O3 system obtained by a sol–gel procedure

The aim of the present work was to prepare a binary MO–Nd₂O₃ system by the sol–gel method and to characterise a series of mixed oxides belonging to the binary MO–Nd₂O₃ system (M = alkaline earth metal = Mg, Ca, Sr) to obtain suitable materials with catalytic properties. The molar ratio between the two oxides was MO/Nd₂O₃ = 95/5. Different precursors as alkaline earth metal oxide source (MO), various starting solution compositions expressed in various molar ratios between reactants and different synthesis parameters (pH, temperature and time of reaction) have been used. The structural study by X-ray diffraction analysis was accomplished based on the X-ray 5.0 program, which has established the presence of the mixtures of crystalline polyphases. The lattice constants, the average size of the crystallites, the average lattice strains and the mass of unit cell variation have been calculated. The program also allowed the calculus of the anisotropy factor, which can give the image of the structural disorder. The surface defects are a consequence of structural changes inside of the crystalline lattice of the solid solutions and are quite important for catalytic properties. Some catalytic activity measurements have established the potential of the prepared sol–gel mixed oxides to be used in the oxidative dehydrogenation process of light alkanes (C₁C₄). Sample 3SrNd was shown to present the best catalytic activity and selectivity in olefins in propane conversion (${\text{C}}_2^{=}\&{\text{C}}_3^{=}$) compared with 4Ca-Nd and 1Mg-Nd samples, which was interpreted as due to a better solid solution formation of Nd³⁺ in SrO, favoured by the close ionic radius of Sr²⁺ and Nd³⁺, as well as by the high basicity of Sr and the presence of a greater number of point defects.     

Homogeneous and Polymer-Supported Catalysts in the Oxidation of α-Pinene with Oxygen

The catalytic activities of nitrogen-containing cobalt complexes, polymer (AN-251 anion exchanger)-supported cobalt complex, and a polymer–salt composition containing molybdenum salt and nonionogenic water-soluble polymers were compared in the oxidation of -pinene.     

Cyclometallated compounds of palladium(II) with a 2,4-pentanedionate: the X-ray crystal structure of

[reaction: see text] Aromatic O-triisopropylsilyl ketoximes were efficiently rearranged to cyclic and acyclic aniline derivatives on reduction with BF3-ethearate/borane. The bulk of the substituents on the silicon atom, the size of the aliphatic ring, and the presence of alkoxy substituents on the aryl group all play an important role in the aniline.     

Facile rearrangement of O-silylated oximes on reduction with boron trifluoride/borane

[reaction: see text] Aromatic O-triisopropylsilyl ketoximes were efficiently rearranged to cyclic and acyclic aniline derivatives on reduction with BF3-ethearate/borane. The bulk of the substituents on the silicon atom, the size of the aliphatic ring, and the presence of alkoxy substituents on the aryl group all play an important role in the aniline.