Growth of single-layer boron nitride dome-shaped nanostructures catalysed by iron clusters.

We report on the growth and formation of single-layer boron nitride dome-shaped nanostructures mediated by small iron clusters located on flakes of hexagonal boron nitride. The nanostructures were synthesized in situ at high temperature inside a transmission electron microscope while the e-beam was blanked. The formation process, typically originating at defective step-edges on the boron nitride support, was investigated using a combination of transmission electron microscopy, electron energy loss spectroscopy and computational modelling. Computational modelling showed that the domes exhibit a nanotube-like structure with flat circular caps and that their stability was comparable to that of a single boron nitride layer.

Formation of nickel-carbon heterofullerenes under electron irradiation.

A way to produce new metal-carbon nanoobjects by transformation of a graphene flake with an attached transition metal cluster under electron irradiation is proposed. The transformation process is investigated by molecular dynamics simulations by the example of a graphene flake with a nickel cluster. The parameters of the nickel-carbon potential (I. V. Lebedeva et al., J. Phys. Chem. C, 2012, 116, 6572) are modified to improve the description of the balance between the fullerene elastic energy and graphene edge energies in this process. The metal-carbon nanoobjects formed are found to range from heterofullerenes with a metal patch to particles consisting of closed fullerene and metal clusters linked by chemical bonds. The atomic-scale transformation mechanism is revealed by the local structure analysis. The average time of formation of nanoobjects and their lifetime under electron irradiation are estimated for the experimental conditions of high-resolution transmission electron microscopy (HRTEM). The sequence of images of nanostructure evolution with time during its observation by HRTEM is also modelled. Furthermore, the possibility of batch production of studied metal-carbon nanoobjects and solids based on these nanoobjects is discussed.

Serum levels of certain trace elements (Ag, Co, Cr) in healthy subjects (part II).

In 95 healthy subjects including 55 women and 40 men the serum levels of Ag, Co and Cr were determined by means of neutron activation analysis using the method of gamma spectrometry without separation of different elements from the sample. It was found that people aged over 60 years had higher serum silver levels than younger subjects. In women a statistically significantly higher serum cobalt level was demonstrated in relation to men. Men and women aged over 60 years had serum chromium levels very similar while women aged below 60 years had lower serum chromium levels.

Serum levels of certain trace elements (Fe, Rb, Se, Zn) in healthy humans (part III).

In 95 healthy subjects serum concentrations of Fe, Rb, Se and Zn were determined by means of neutron activation analysis using the method of gamma spectrometry without isolation of different elements from the sample. The studied subjects were divided into 4 groups according to sex and age. In the serum of women rubidium concentration decreased with age. On the other hand, the serum levels of Fe, Zn and Se were similar in the studied groups.

Serum levels of certain trace elements (Cu, Au, Mn) in healthy subjects (Part I).

In 95 healthy subjects of either sex the serum concentrations of Cu, Au, and Mn were determined by means of neutron activation analysis (NAA). It was found that copper concentration in the serum of healthy subjects increased with age up to 70 years of life. In subjects aged below 60 years a higher gold level was demonstrated in the serum than in the subjects aged above 60 years. Serum manganese level was higher in men than in women.

Cytotoxic effect of fatty acids in vitro on Ehrlich exudative carcinoma cells and normal exudative cells (leukocytes).

A mixture of pure fatty acids isolated hydrolytically from linseed oil in the form of water-soluble salts with ethanolamine were examined for cytotoxicity for Ehrlich carcinoma and normal exudative cells. Cytotoxicity of the mixture was similar to that of salts of oleic and linolenic acids. On the other hand, the mixture of fatty acids and oleic acids was more toxic for normal exudative cells than linolenic acid.