The detailed numerical simulations of the IV-characteristics of Josephson junction under external electromagnetic radiation show devil's staircases within different bias current intervals. We have found that the observed steps form very precisely continued fractions. Increasing of the amplitude of radiation shifts the devil's staircases to higher Shapiro steps. The algorithm of appearing and detection of the subharmonics with increasing radiation amplitude is proposed. We demonstrate that subharmonic steps registered in the famous experiments by A. H. Dayem and J. J. Wiegand [Phys. Rev 155, 419 (1967)] and J. Clarke [Phys. Rev. B 4, 2963(1971] also form continued fractions.Josephson junctions are regarded as excellent model systems for studying a variety of nonlinear phenomena in different fields of science [1, 2] such as frequency locking, chaos, charge density waves, transport in superconducting nanowires, interference phenomena and others [3][4][5][6]. These phenomena, and especially properties of the Shapiro steps (SS) [7] in Josephson junctions are very important for technical applications [8].In a Josephson system driven by an external microwave radiation, the so-called devil's staircase (DS) structure has been predicted as a consequence of the interplay of the Josephson plasma frequency, and the applied frequency (see Refs. [9,10] and references therein). To stress the universality in the scenario presented, we note that the devil's staircase appears in other systems including the infinite spin chains with long-range interactions [11], frustrated quasi-two-dimensional spin-dimer system in magnetic fields [12], systems of strongly interacting Rydberg atoms [13], and fractional quantum Hall effect [14]. A series of fractional synchronization regimes (devils staircase) in a spin-torque nano-oscillator driven by a microwave field was experimentally demonstrated [15]. The devil's staircase is considered as an outstanding example of a 'phase diagram' in physics, because it shows a high degree of self-organization [16].A detailed experimental investigation of the subharmonic SS in SNS junctions were made by J.Clarke [17]. He found that the application to a junction of rf electromagnetic radiation of frequency Ω induced constantvoltage current steps at voltages (n/m) Ω/(2e), where n and m are positive integers. The results were explained based on the idea that phase difference in Josephson junction is increasing in time in a uniform manner and current-phase relation is nonsinusoidal. The junction generates harmonics when it biased at some voltage and these harmonics may synchronize with the applied radiation to produce the steps. Another famous experiment on the behavior of thin-film superconducting bridges in a microwave field by A. H. Dayem and J. J. Wiegand [18] also demonstrates the production of constant-voltage steps in the IV-characteristics. Some experimental results are explained by nonsinusoidal current-phase relation [19,20]. Ben-Jacob with coauthors [10] found the subharmonic steps within the resistiv...

The devil's staircase structure arising from the complete mode locking of an entirely nonchaotic system, the overdamped dc+ac driven Frenkel-Kontorova model with deformable substrate potential, was observed. Even though no chaos was found, a hierarchical ordering of the Shapiro steps was made possible through the use of a previously introduced continued fraction formula. The absence of chaos, deduced here from Lyapunov exponent analyses, can be attributed to the overdamped character and the Middleton no-passing rule. A comparative analysis of a one-dimensional stack of Josephson junctions confirmed the disappearance of chaos with increasing dissipation. Other common dynamic features were also identified through this comparison. A detailed analysis of the amplitude dependence of the Shapiro steps revealed that only for the case of a purely sinusoidal substrate potential did the relative sizes of the steps follow a Farey sequence. For nonsinusoidal (deformed) potentials, the symmetry of the Stern-Brocot tree, depicting all members of particular Farey sequence, was seen to be increasingly broken, with certain steps being more prominent and their relative sizes not following the Farey rule.

This study investigated the effects of the L-17 compound of the group of substituted 5R1, 6H2-1,3,4-thiadiazine-2-amines on the inflammatory cellular infiltration and myocardial remodelling which occurs after acute myocardial infarction (MI) in rats. The study is based upon recent clinical and experimental work which demonstrated the role of local and systemic inflammatory reactions in postinfarction remodelling. Acute MI in rats was induced by left coronary artery coagulation. Animals were sacrificed on day one, five and seven after MI induction. The myocardiumal samples were taken from all parts of the heart and examined by histology. This included areas of infarction, infraction and areas that were peri-infarctiom and left ventricular areas distant from the damaged tissues. Serum activity of creatine phosphokinase (CPK), aspartate aminotransferase (AST), isoenzymes 1 and 2 and lactate dehydrogenase (LDH1-2) were investigated on the same three days, before and in the process of MI development was investigated (at days 1, 5 and 7). The L-17 compound to not only decreased the area of initial infarction but also changed the pattern of inflammatory reaction in the affected myocardium fundamentally. Laboratory studies of effects of L-17 compound on the development and course of experimental MI showed that administration decreased blood AST and CPK levels significantly and provided useful the data about the correlation between the activity of these enzymes and the dimensions of the significantly necrotic area. In this model of experimental MI the use of the L-17 compound induced led to the replacement of the exudative destructive inflammation that is seen under standard conditions with a more cellular "productive" pattern of inflammation, with associated reduction in initial necrosis area and the, decrease in myocardial ischaemia and reperfusion injury may account for the accelerated repair process.

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It is reputed that the ideal therapeutic approaches to treatment of patients with acute coronary syndrome (ACS) and myocardium infarction (MI) should be aimed at the inflammation reaction triggers. This study investigated the effectiveness of the impact of L- 17 compound of the group of 5- phenyl substituted-6H-1,3,4-thiadiazine-2-amines upon the course of experimental MI as compared to the impact of a preparation, officially registered in Russia as an immunomodulator, Tamerit, belonging to phthalhydrazid derivative substance. Acute MI in rats was induced by left coronary artery coagulation. Histological study of the myocardium sections and biochemical analysis has been carried out at the 1st and 7th days of the experimental MI. The conducted investigations have shown that under the action of immunocorrectors the inflammation reaction character changes, exudative/destructive inflammation is replaced by a proliferative-cellular one. Animals' blood biochemical analysis at the background of L-17 and Tamerit introduction has shown a decrease of aminotransferases and lactatedehydrogenases activity in blood as compared to the reference group of animals' indicators, which is evidently caused by epicardial injury of myocardium and lesser amount of the alternative cardiomyocytes. At the same time, no noticeable difference in biochemical characteristics in groups, having been treated to immunomodulators of different chemical composition was identified, which is the sign of the essential similarity of their impact. Thus, immunocorrectors of different chemical groups (Tamerit and compound L17) diminish the volume of initial myocardial infarction and accelerate the granulation processes in course of MI, and represent a new category of treatment agents.

The phase dynamics of Josephson junctions under external electromagnetic radiation is studied through numerical simulations. Current-voltage characteristics, Lyapunov exponents and Poincaré sections are analyzed in detail. It is found that the subharmonic Shapiro steps at certain parameters are separated by structured chaotic windows. By performing a linear regression on the linear part of the data, a fractal dimension of D = 0.868 is obtained, with an uncertainty of ±0.012. The chaotic regions exhibit scaling similarity and it is shown that the devil's staircase of the system can form a backbone that unifies and explains the highly correlated and structured chaotic behavior. These features suggest a system possessing multiple complete devil's staircases. The onset of chaos for subharmonic steps occurs through the Feigenbaum period doubling scenario. Universality in the sequence of periodic windows is also demonstrated. Finally the influence of the radiation and Josephson junction parameters on the structured chaos is investigated and it is concluded that the structured chaos is a stable formation over a wide range of parameter values.

Nanocluster polyoxometalates with a structure of buckyball (fullerene) are a promising means of targeted delivery of drugs in the body. In this paper, based on an analysis of histological sections of liver and kidney and peripheral blood, showed a significant reduction of toxicity of buckyballs, containing ions of molybdenum (VI), the substitution of Mo (V) ions to Fe (III), in contrast to buckyballs based on Mo (V). The absence of accumulation of molybdenum in rats with a daily intramuscular injection of aqueous solutions of both drugs within a month was confirmed

The purpose of this study was to determine the specific features of the morphological restructuring of the myocardium in the early stage of experimental diabetes mellitus (DM). Experimental type 1 DM rat model was developed by intraperitoneal injection of alloxan solution at a dose of 30 mg per 100 g body mass. After 1 month, 3 mL of blood was drawn by heart puncture and the plasma separated by centrifugation for biochemical analysis. Plasma glucose, insulin, and glycosylated haemoglobin in whole blood were determined. Light microscopy and morphometric studies were conducted of histological slices of the hearts of experimental animals. The investigation of heart morphology showed a statistically significant alteration in chamber wall thickness in the right auricle in rats with alloxan-induced DM. A change in cardiomyocyte diameter in myocardium slices was observed in all chambers of DM rats except for the left ventricle. Average cardiomyocyte diameter in rats with experimental DM increased by 26.6% and 15.5% in the right auricle and right ventricle, respectively, while average cardiomyocyte diameter in the left auricle decreased by 20.8%. Histological investigation of the heart following alloxan injection demonstrated, under the epicardium, distended vessels of the venous collecting microcirculatory system. Aggregation and agglutination of red blood cells and endothelial cell destruction were found in some vessels. In the early stage of DM development, structural alterations in the microcirculatory channels and myocardiocytes can be observed in the heart. These structural alterations were most evident in the right chambers of the heart. Anat Rec, 298:396-407, 2015Rec, 298:396-407, . V C 2014 Wiley Periodicals, Inc.