Influence of Bottom Inclination on the Flow Structure in a Rotating Convective Layer

The formation of convective flows in a rotating cylindrical layer with an inclined bottom and free surface is studied.Convection is driven by localized cooling at the center of the upper free surface and by rim heating at the bottom near the sidewall.The horizontal temperature difference in a rotating layer leads to the formation of a convective flow with a complex structure.The mean meridional circulation,consisting of three cells,provides a strongly non-uniform differential rotation.As a result of the instability of the main cyclonic zonal flow,the train of baroclinic waves appears in the upper layer.The baroclinic waves provide most of the heat transfer in the middle radii and are responsible for strong temperature and velocity fluctuations.It is shown that the inclination of the bottom is a crucial factor for the structure of the convective cells and the dynamics of the baroclinic waves.The increase in the inclination angle leads to a significant increase in the energy of the waves.The obtained results may be important for heat and mass transfer in various geophysical and industrial systems,including transport of various additives and impurities in rotating crucibles,and crystallization processes.

Periodicities in Solar Activity, Solar Radiation and Their Links with Terrestrial Environment

Solar magnetic activity is expressed via variations of sunspots and active regions varying on different timescales. The most accepted is an 11-year period supposedly induced by the electromagnetic solar dynamo mechanism. There are also some shorter or longer timescales detected: the biennial cycle (2 - 2.7 years), Gleisberg cycle (80 - 100 years), and Hallstatt’s cycle (2100 - 2300 years). Recently, using Principal Component Analysis (PCA) of the observed solar background magnetic field (SBMF), another period of 330 - 380 years, or Grand Solar Cycle (GSC), was derived from the summary curve of two eigenvectors of SBMF. In this paper, a spectral analysis of the averaged sunspot numbers, solar irradiance, and the summary curve of eigenvectors of SBMF was carried out using Morlet wavelet and Fourier transforms. We detect a 10.7-year cycle from the sunspots and modulus summary curve of eigenvectors as well a 22-year-cycle and the grand solar cycle of 342 - 350-years from the summary curve of eigenvectors. The Gleissberg centennial cycle is only detected on the full set of averaged sunspot numbers for 400 years or by adding a quadruple component to the summary curve of eigenvectors. Another period of 2200 - 2300 years is detected in the Holocene data of solar irradiance measured from the abundance of 14C isotope. This period was also confirmed with the period of about 2000 - 2100 years derived from a baseline of the solar background magnetic field, supposedly, caused by the solar inertial motion (SIM) induced by the gravitation of large planets. The implication of these findings for different deposition of solar radiation into the northern and southern hemispheres of the Earth caused by the combined effects of the solar activity and solar inertial motion on the terrestrial atmosphere is also discussed.

Molecular Dynamics Simulation of Interaction of Short Lysine Brush and Oppositely Charged Semax Peptides

The possibility of complex formation by short lysine brush and therapeutic Semax peptides was investigated using molecular dynamics method. Lysine dendrimers and polymer brushes are used for drug and other (e.g., DNA, peptides, and polysaccharides) molecules delivery to different target cells. It is known that they could penetrate blood brain barrier. Since short lysine brush is nontoxic, a system containing of such brush and 8 oppositely charged Semax peptides was studied. It was obtained that stable complexes consisting of brush and peptides formed and structures of these complexes were investigated. Such complex can be used in future for delivery of Semax peptides to brain since these peptides have significant antioxidant, antihypoxic and neuroprotective effects.

Arterial hypertension and electrocardiographic diagnosis of left ventricular hypertension in the group of geriatric patients with coronary heart disease living in the far north

As a result of research, high prevalence of arterial hypertension has been identified in the group of patients with coronary heart disease aged 60 and older. Most often, occurring form of arterial hypertension among geriatric patients is isolated systolic arterial hypertension (ISAH). The comparison of two ethnic groups of the population has showed higher levels of systolic and diastolic blood pressure (SBP and DBP) in the group of patients of non-indigenous nationality, rather than Yakut patients. Correlation was recorded in the group of non-indigenous patients as they age. Significant increase in the level of SBP was identified in the group of senile and long-livers than in the elderly. Detection of ECG signs of LVH showed the lowest specificity of Cornell voltage criterion comparing to Sokolow-Lyon criterion with its more often occurrence. ECG-signs of left ventricle hypertrophy are significantly more often established by Sokolow-Lyon criterion for men, Cornell voltage—for women. Correlation has been found between the presence of LVH and combination of Cornell voltage criterion with both Gubner-Ungerleider and Sokolow-Lyon criteria.

The angiotension converting enzyme (ACE) gene I/D polymorphism in different ethnic groups of geriatric age living in the Far North

The study of ACE gene I/D polymorphism has been carried out in elderly, senile and long-liver patients with coronary heart disease (CHD) taking into account their nationality, age and sex. It has been recorded that with the increase of age there is a decrease in the frequency of the genotype ACE*I/*I and a tendency of increase in the frequency of the genotype ACE*D/*D. A comparative analysis of genotypes АСЕ*D/*D and АСЕ*D/*I has showed sex differences in the frequency of homozygous genotype detection. Left ventricular hypertrophy can be observed significantly more often among carriers of genotype ACE*I/*I established by Sokolow-Lyon ECG signs. Association analysis of ACE gene I/D polymorphism has registered significant differences in BMI and blood lipid parameters.

Large Room Temperature Magneto-Resistance in Magnetically Disordered Fe_1.5Ti_0.5O_3-δThin Films

Electronic transport properties of magnetically disordered R(-3)c phase Fe1.5Ti0.5O3-δ thin films epitaxially grown on Al2O3(0001) substrates have been studied. The measured magnetization in configurations with the magnetic field perpendicular and parallel to the film plane shows weak values of 0.1μB/formula compared to the theoretical value of 2μB/formula and a strong anisotropy with no saturation in perpendicular configuration. These properties are associated with the ato- mic scale disorder of Ti/Fe ions along c-axis. At zero-magnetic field and within the temperature range of 80 K to 400 K, the conduction mechanism appears to be Efros-Shklovskii variable range hopping with a carrier localization length of ξ0= 0.86nm. Magneto-resistance (MR) is positive in perpendicular configuration, while it is negative in parallel configuration, with significant values of MR = 27%- 37% at room temperature at 9 Tesla. Electron localization lengths were deduced from experiment for different external magnetic fields. The origin of magneto-resistance observed in experiment, is discussed.

The research works of Coulomb and Amontons and generalized laws of friction

The paper is devoted to the contributions of Coulomb and Amontons to the physics of friction from the viewpoint of current discussions and attempts to formulate generalized laws of friction.

60 years of Rabinowicz' criterion for adhesive wear

60 years ago, in 1958, Ernest Rabinowicz published a 5 page paper titled "The effect of size on the looseness of wear fragments" where he suggested a criterion determining the minimum size of wear particles. The criterion of Rabinowicz is based on the consideration of the interplay of elastic energy stored in "asperities" and the work of separation needed for detaching a wear particle. He was probably the first researcher who explicitly emphasized the role of adhesion in friction and wear. In a recent paper in Nature Communications, Aghababaei, Warner and Molinari confirmed the criterion of Rabinowicz by means of quasi-molecular dynamics and illustrated the exact mechanism of the transition from plastic smoothing to formation of wear debris. This latter paper promoted the criterion of Rabinowicz to a new paradigm for current studies of adhesive wear. The size arguments of Rabinowicz can be applied in the same form also to many other problems, such as brittle-ductile transition during indentation, cutting of materials or ultimate strength of nano-composites.