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Quantum-mechanical models for the formation of metal–carbon complexes of Co, Ni, Cu, and Zn ions with С60 fullerene molecules and single-wall С48 carbon nanotubes (SWCNTs) are proposed. The results of calculations show that, in aqueous solutions of electrolytes, Co, Ni, Cu, and Zn ions can be adsorbed into the С60 fullerene and С48 SWCNT surfaces with the formation of stable carbon-nanomaterial—metal (CNM—M) complexes; in this case, the minimum energy of the С60–М complex for Co and Cu ions corresponds to the position above the С6 cell center; for a Ni ion, above the single С–С bond in the С6 cell; and for a Zn ion, above the C atom. The optimized states of the С48–М complexes correspond to the position of metal ions above the С6 cell center. [ABSTRACT FROM AUTHOR]

Abstract: The new approach for the determination of orbital exponents and contracted coefficients for STO-3G family basis sets has been proposed. Calculations of the necessary coefficients have been performed using Mathcad program package with Minerr solving block. This approach has been used to perform the approximation of the Slater-type orbital (STO) by three Gaussian-type orbitals (GTO). The performance of such modified basis sets has been tested for the calculations of atomic energies using STO(0)-3G basis set and for nuclear magnetic shielding tensors using STO(1M)-3G basis set. The obtained atomic energies are characterized by lower values than those calculated using old parameters. The results for 1H and 13C chemical shifts calculations demonstrate better agreement with the experimental data compared to the data obtained using standard basis sets, such as 6-311G (2d, p), cc-pVDZ and pcS-1. Required time of calculations using the basic set suggested by us is less than the time spent on the calculation using standard basic sets with a similar number of basis functions. Physically adapted and at the same time small by size basic set STO(1M)-3G is perspective for the calculation of magnetic properties of big molecular systems. Proton and 13C chemical shifts have been calculated for molecules of adenosine monophosphate (AMP) and flavinadenine dinucleotide (FAD), that play an important role in various biological processes. For both molecules the results of the calculation have shown values close to the experimental data. [ABSTRACT FROM AUTHOR]

Vaccinium myrtillus L. is a common shrub in the herbaceous layer of pine forests. In connection with resistance to pollution it has been widely used in the environmental monitoring based on heavy metal accumulations in the foliage. The present study investigates leaves of bilberry growing under influence of emissions from a Zn–Pb smelter. Determination of heavy metal levels by AAS revealed enhanced accumulations of Zn, Pb, Cd, and Fe, and the level of Zn fell into the toxic range compiled for plants of average sensitivity. To verify the significance of metal accumulations occurring in the studied plant, the concentrations of phenolics were quantified by measuring UV absorption of foliage extracts. Phenolics can be used as a potential biomarker of pollution because they participate in plant’s response to accumulation of heavy metals, acting as antioxidants able to scavenge free radicals produced by metal ions. Leaves collected near the smelter contained significantly higher amounts of phenolics. Since these compounds are also responsible for ecological interactions, changes in their concentrations resulting from heavy metal accumulations might also influence other organisms in the ecosystem. To study the role of phenolics in heavy metal accumulations at the cellular level, a special fixation was applied for TEM, involving glutaraldehyde with caffeine, to precipitate phenolics in the cell. A histochemical reaction showed significantly higher electron-opacity, most probably deposits of phenolics, in cells of the leaves collected near the smelter. The subsequent degenerative changes in mesophyll of these leaves were characterized by increased contents of heterogeneous multivesicular structures, degeneration of chloroplasts, and disorganisation of membranes leading to death of the cell and necrosis. [ABSTRACT FROM AUTHOR]

The article reports on the cadmium accumulation in fetus and placenta of bank voles. Cadmium was found to have unique biological role. However it is well known for its toxicity with regard to the reproduction and development of young animals. Cadmium is easily absorbed and remains a relatively long time within the tissues. Its general occurrence in the environment is a significant threat to young organisms, during both prenatal and postnatal development. Placenta is supposed to be an effective barrier to toxic elements. Another harmful influence of cadmium on pregnant females and their embryos is connected with its antagonistic effect on absorption and distribution of nutrition in the organism.

Calcified tissues are good indicators of exposure to environmental pollution since the mineral phase incorporates heavy metals to which it is exposed during development. Analysis of these specimens is difficult due to the low concentration of the elements of interest compared with the high concentration of the matrix elements. ICP-MS allows rapid multielement determination of samples and a method for the determination of trace elements in calcified tissues is presented with reference to an SRM of Bone Ash (NIST 1400). [ABSTRACT FROM AUTHOR]

No Abstract. [ABSTRACT FROM AUTHOR]