Cerenkov generation of high-frequency confined acoustic phonons in quantum wells

We analyze the Cerenkov emission of high-frequency confined acoustic phonons by drifting electrons in a quantum well. We find that the electron drift can cause strong phonon amplification (generation). A general formula for the gain coefficient, alpha, is obtained as a function of the phonon frequency and the structure parameters. The gain coefficient increases sharply in the short-wave region. For the example of a Si/SiGe/Si device it is shown that the amplification coefficients of the order of hundreds of 1/cm can be achieved in the sub-THz frequency range.Comment: 4 pages, 2 figures. Submitted to AP

Electron-phonon interaction via Pekar mechanism in nanostructures

We consider an electron-acoustic phonon coupling mechanism associated with the dependence of crystal dielectric permittivity on the strain (the so-called Pekar mechanism) in nanostructures characterized by strong confining electric fields. The efficiency of Pekar coupling is a function of both the absolute value and the spatial distribution of the electric field. It is demonstrated that this mechanism exhibits a phonon wavevector dependence similar to that of piezoelectricity and must be taken into account for electron transport calculations in an extended field distribution. In particular, we analyze the role of Pekar coupling in energy relaxation in silicon inversion layers. Comparison with the recent experimental results is provided to illustrate its potential significance

Hypoxia-inducible factor: basic biology and involvement in cardiovascular pathology

Molecular epidemiological studies conducted to date reveal a close relationship between the polymorphism of the HIF system genes with a wide range of cardiovascular, inflammatory, and oncological diseases. The study of the HIF system can contribute to the discovery of new targets and methods of pharmacological effects for the treatment of cardiovascular, oncological, rheumatological, and endocrinological patholog

The Concept of Ecologically Oriented Progress and Natural Resource Preservation

The most important issue of scientific and technological progress is considering the environment challenges of industrial development. It means that the progress must be ecologically oriented and environmentally friendly. The most adequate concept for the approach to the issue of "man - society – nature" relations is the ontology of the noosphere - the idea of a common space for human beings and nature. It presents an ideal example of an optimistic attitude towards the coordination between accelerating the scientific and technological development and natural resource saving. However, to maintain the balance between human needs and environmental processes determined by this concept, it is essential to include the lean production training into technological development of society

Influence of the shape of the particles covering the metal surface on the dispersion relations of surface plasmons

Abstract The Green function method was used for calculation of dispersion relations of surface plasmon generated at the metal surface covered by ellipsoidal particles. The influence of the shape of the particles on the surface plasmon dispersion relations was studied. It was established that both s-and p-polarized surface plasmons can be excited at the surface covered by the particles. It was shown that the shape of the particles covering the surface strongly influences on the surface plasmons dispersion

Preliminary report on taxonomical position of Vavilovia formosa (Stev.) Fed. evidenced from morphological and molecular data

The Fabeae Rchb. (syn. Vicieae Adans.) tribe includes numerous representatives of special agricultural value and has; therefore, received considerable attention. Despite (or because of) this, there are certain problems concerning its systematics and phylogeny. One of the most problematic groups within the tribe is the monotypic genus Vavilovia Fed. It includes very small perennial plants inhabiting the highlands of the Caucasus, Turkey, Lebanon and Iran. Although almost two centuries have passed since the first description of this plant was reported by C. Steven (more detailed information on the history of its taxonomical status is presented in (1), its status remains unresolved. Previously it was included in the genera Orobus, Lathyrus, Pisum, or treated as a separate genus, Alophotropis Grossh. or Vavilovia Fed. The most recent monographs on the family tend to describe its status as a monotypic genus including a single species, Vavilovia formosa (Stev.) Fed. (2)

Study to Investigate the anti-inflammatory effect of Codelac® Broncho with Thymus Serpyllum (elixir) in comparison with reference drug Fenspiride (syrup) using accute carrageenan-induced paw inflammation model

Evaluation of anti-inflammatory action of Codelac® Broncho with Thymus Serpyllum (elixir) in comparison with Fenspiride was carried out on the model of acute carrageenan inflammation of the paws in rats. As a result of the study, it turned out that obtained data indicate a more pronounced anti-inflammatory activity of Codelac® Broncho with Thymus Serpyllum in comparison with Fenspiride, on the model of acute carrageenan inflammation of the paw in rat