The study of the biological activities of Ziziphora clinopodioides

The aim of the current study was to determine the chemical constituents of essential oil and to study the antibacterial and antioxidant activities of essential oil and the extracts obtained from the raw material of Ziziphora wild growing in the floras of Armenia and Artsakh cultivated in the hydroponic conditions. The essential oils were obtained by the method of hydro-distillation. The determination of the essential oil constituents were performed by the GC-MS method. Agar disk diffusion method was used to study the antimicrobial activity of essential oils. The antioxidant activity determination was carried out DPPH test by the spectrophotometric method, at the same time IC50 was determined. The highest values of the essential oils yield (1.25 ± 0.01%) and IC50 13.83±0.218(x10-5)g/l) were received for the plant cultivated in hydroponic conditions. For the first time in the above studied samples, by the method of GC-MS more than 70 components were revealed. The results of the study showed that essential oils of Ziziphora exhibit antimicrobial activity and the extracts revealed relatively expressed antioxidant activity. The study results show the future prospects of the use of Ziziphora not only as the source of flavonoids and essential oils, but also antimicrobial and antioxidant agents

Wave dynamics of generalized continua

This monograph is devoted to problems of propagation and stability of linear and nonlinear waves in continuous media with complex structure. It considers the different media, such as solid with cavities, preliminary deformed disperse medium, solid with porosity filled by the electrically conductive and non-conductive liquid, magnetoelastic, piezo-semiconductors, crystals with dislocations, composites with inclusions, an electrically conductive asymmetrical liquid, a mixture of gas with a drop liquid. The book also considers the propagation of a laser beam through a two-level medium. The presented results are based on methods of evolution and modulation equations that were developed by the authors. The book is intended for scientific and technical researchers, students and post-graduate students specializing in mechanics of continuous media, physical acoustics, and physics of the solid state

Localized nonlinear waves in a semiconductor with charged dislocations

To describe a nonlinear ultrasonic wave in a semiconductor with charged dislocations, an evolution equation is obtained that generalizes the well-known equations of wave dynamics: Burgers and Korteweg de Vries. By the method of truncated decompositions, an exact analytical solution of the evolution equation with a kink profile has been found. The kind of kink (increasing, decreasing) and its polarity depend on the values of the parameters and their signs. An ultrasonic wave in a semiconductor containing numerous charged dislocations is considered. It is assumed that there is a constant electric field that creates an electric current. The situation is similar to the case of the propagation of ultrasonic waves in piezoelectric semiconductors, but in the problem under consideration, instead of the electric field due to the piezoelectric properties of the medium, the electric field of dislocations appears