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  • Author: V. V. Petrenko x
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Abstract

We study size-at-age and sexual variability of morphometric characteristics of the marsh frog. According to the size of the body, males were divided into three size-age groups (juvenis, subadultus, adultus), females — into four groups (juvenis, subadultus, adultus, adultus-I). We found that the chronological age of frogs (skeletochronology) does not always correspond to their biological age (size and proportions of the body). We noted that the semi-adult males are reliably larger than females by mean values of 26 studied morphometric characters. Males and females of “adultus” group do not differ by linear body size, significant differences were found in body proportions (7 characters). For the females of “adultus-I” group, the mean values of 26 characters are significantly larger than for “adultus” males. The results of our study showed that with the age of the marsh frog, the level of exhibition, directionality and structure of morphometric sex differences changes.

Abstract

Doped with Ga lead telluride was taken as a model object to explain the nature of group-III deep levels in IV-VI semiconductors and to elucidate the vapour phase doping mechanism. For this goal, interaction of various gallium-containing molecules with defect-free crystal as well as with native defects in PbTe was considered. Formation energies for different point defects created in PbTe as a result of interaction the Ga2Te molecules, Ga2 dimers and single Ga atoms with a host crystal were calculated using density functional theory. Particularly GaPb and Gai together with formation of accompanied self interstitials Pbi in various charge states were examined. In addition we propose the new type of defects - the impurity complex (2Ga)Pb which looks like <111>-oriented gallium dumbbell. Calculations suggest the double donor behaviour and DX-like properties of this defect together with extremely low formation energy values. Namely, (2Ga)Pb centres are preferably formed under Ga2Te doping while (Ga2)Pb+Pbi ones are formed under Ga2 or Ga doping. In all cases, formation energies are negative and resulting defect concentration is determined by reaction kinetics only. Mechanisms of the lead vacancy compensation with the vapour phase doping are considered as well.

Abstract

New gelatin-based cryostructurates have been elaborated and tested as scaffolds for three-dimensional (3D) cell culturing. Scaffold preparation included dissolution of Type A gelatin in dimethylsulfoxide, freezing of such solution, cryoextraction of crystalline phase with cold ethanol, cross-linking of gelatin with carbodiimide in ethanol medium, treatment of the matrix with ethanolic solution of Tris and tanning of the matrix with formaldehyde dissolved in ethanol. The use of organic media during all the preparation stages ensured the sterility of the scaffolds. The matrices thus prepared were seeded with human adipose tissue multipotent mesenchymal stromal cells to confirm the biocompatibility of scaffolds and their possibility to provide necessary environment for the cell growth and differentiation. The cells attached onto the surface of the pore walls, proliferated and differentiated into osteogenic and adipogenic lineages. These results demonstrate that gelatin-based cryostructurates prepared in the sterility ensuring organic media can be used as scaffolds for tissue engineering purposes.

Abstract

The performance characteristics of modern electrochemical energy storage devices are largely determined by the processes occurring at charge separation interfaces, as well as by the evolution of the structure, composition and chemistry of electrodes and electrolytes. The paper reviews the principal applications of neutron scattering techniques in structural studies of electrode materials and electrochemical interfaces in the course of their operation (operando mode) with an accent to Li-ion batteries. The high penetrating power of thermal neutrons makes it possible to study complex systems that are the closest to real electrochemical cells. The recent progress and future tasks in the development of the neutron scattering methods (diffraction, reflectometry, small-angle scattering) for various types of electrodes/interfaces in Li energy storage devices are discussed.

Abstract

The following compendium reviews the development and establishment of optical spectroscopy as an analytical method for battery material components and electrochemical reactions. The interaction of light with matter is a sensitive and nondestructive way to characterize any sample state, i.e. solids, liquids or gases. Special attention is devoted to infrared and ultraviolet spectroscopy, covering a wavelength range from 12 μm to 200 nm, as well as Raman scattering spectroscopy, in order to excite different vibrational/rotational lattice modes and transitions of valence electrons. This allows an insight into structural properties, chemical composition, oxidation states or kinetic processes. The development of spectroelectrochemical in situ cells allows the investigation of various battery components, e.g. working and counter electrode, separator, electrolyte as well as interfaces between these components. These powerful tools allow the evaluation of the functionality, stability and safety aspects of an electrochemical storage cell.

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