Analysis of azimuthal magnetorotational instability of rotating magnetohydrodynamic flows and Tayler instability via an extended Hain-Lüst equation.

We consider a differentially rotating flow of an incompressible electrically conducting and viscous fluid subject to an external axial magnetic field and to an azimuthal magnetic field that is allowed to be generated by a combination of an axial electric current external to the fluid and electrical currents in the fluid itself. In this setting we derive an extended version of the celebrated Hain-Lüst differential equation for the radial Lagrangian displacement that incorporates the effects of the axial and azimuthal magnetic fields, differential rotation, viscosity, and electrical resistivity. We apply the Wentzel-Kramers-Brillouin method to the extended Hain-Lüst equation and derive a comprehensive dispersion relation for the local stability analysis of the flow to three-dimensional disturbances. We confirm that in the limit of low magnetic Prandtl numbers, in which the ratio of the viscosity to the magnetic diffusivity is vanishing, the rotating flows with radial distributions of the angular velocity beyond the Liu limit, become unstable subject to a wide variety of the azimuthal magnetic fields, and so is the Keplerian flow. In the analysis of the dispersion relation we find evidence of a new long-wavelength instability which is caught also by the numerical solution of the boundary value problem for a magnetized Taylor-Couette flow.

Stabilizing and destabilizing perturbations of PT-symmetric indefinitely damped systems.

Eigenvalues of a potential dynamical system with damping forces that are described by an indefinite real symmetric matrix can behave as those of a Hamiltonian system when gain and loss are in a perfect balance. This happens when the indefinitely damped system obeys parity-time ( ) symmetry. How do pure imaginary eigenvalues of a stable -symmetric indefinitely damped system behave when variation in the damping and potential forces destroys the symmetry? We establish that it is essentially the tangent cone to the stability domain at the exceptional point corresponding to the Whitney umbrella singularity on the stability boundary that manages transfer of instability between modes.

Exceptional points in a microwave billiard with time-reversal invariance violation.

We report on the experimental study of an exceptional point (EP) in a dissipative microwave billiard with induced time-reversal invariance (T) violation. The associated two-state Hamiltonian is non-Hermitian and nonsymmetric. It is determined experimentally on a narrow grid in a parameter plane around the EP. At the EP the size of T violation is given by the relative phase of the eigenvector components. The eigenvectors are adiabatically transported around the EP, whereupon they gather geometric phases and in addition geometric amplitudes different from unity.

[The indices of physical development and cardiovascular system adaptation in Vladivostok medical university students].

Height-weight ratios were measured in 190 high medical students (98 youths and 92 girls at the age of 18 to 21 years). At the same time the growth rates were in agreement with the average statistical normal values, underweight was detected in 32% of the youths and in 21% of the girls. There was a direct relation of systolic blood pressure in both youths and girls and an inverse relation of heart rate to the body mass index. Although the examinees were apparently healthy individuals, half of them were found to have sinus nodal regulatory stress, as evidenced by analysis of variance for cardiac rhythms.

Contact-induced crystallinity for high-performance soluble acene-based transistors and circuits.

The use of organic materials presents a tremendous opportunity to significantly impact the functionality and pervasiveness of large-area electronics. Commercialization of this technology requires reduction in manufacturing costs by exploiting inexpensive low-temperature deposition and patterning techniques, which typically lead to lower device performance. We report a low-cost approach to control the microstructure of solution-cast acene-based organic thin films through modification of interfacial chemistry. Chemically and selectively tailoring the source/drain contact interface is a novel route to initiating the crystallization of soluble organic semiconductors, leading to the growth on opposing contacts of crystalline films that extend into the transistor channel. This selective crystallization enables us to fabricate high-performance organic thin-film transistors and circuits, and to deterministically study the influence of the microstructure on the device characteristics. By connecting device fabrication to molecular design, we demonstrate that rapid film processing under ambient room conditions and high performance are not mutually exclusive.

[The influence of polyunsaturated fat acids on the development of artificially caused exudative skin necrosis in rats].

Development of exudative skin necrosis in female rats of Vistar line was caused by Selye method (with help of subcutaneons injections of sodium chlorate). The number of rats which got skin necrosis was bigger than when animals were fed on food containing butter or sardine fat, at that in the second case bigger than first one. The necrosis area in rats, which were fed on different rations, was the some.

[Effect of stress on postnatal growth in weight of rat body and adrenal gland]. / Vliianie stressa na postnatal'nyi rost massy tela i nadpochechnikov krys.

Seven-week male Wistar rats weighing 145-155 g were housed 10 (control) or 20 (crowded) per cage (50 x 35 x 15 cm). Groups of control and crowded animals were decapitated within 0.5, 1, 3, 7, 14, 21, 28, 35, 56, 70, and 98 days of experiment. The keeping of rats in crowding conditions induced chronic stress, which developed, according to phase changes in plasma concentration of corticosterone and adrenal content of cholesterol, through the stages alarm, resistance, and exhaustion. The postnatal growth of body weight in the stressed rats was behind that in the control. Under the crowding conditions, the adrenal weight did not undergo significant increase, since the stress-induced hypertrophy of the zona fasciculata was compensated by the proportional suppression of the postnatal growth of the zona reticularis. After 56 days, the postnatal growth of the hypertrophied fascicular zone was delayed in the experimental rats.

[Cytoprotective effect of ethyl esters of n-3 polyunsaturated fatty acids]. / Tsitoprotektivnaia aktivnost' kontsentrata étilovykh éfirov n-3 polienovykh zhirnykh kislot.

Protective properties of n-3 and n-6 polyunsaturated, monosaturated and saturated fatty acids (respectively, n-3 PUFA, n-6 PUFA, MUFA and SFA) against ethanol induced hemorrhagic gastric mucosal lesions were compared. Female Wistar rats (90-100 g) were fed to four weeks semisyntethic diets containing 9% butter (SFA-diet), 6% butter and 3% olive oil (MUFA-diet), 6% butter and 3% sunflower oil (n-6 PUFA-diet) or 6% butter and 3% concentrate of n-3 PUFA ethyl esters (n-3 PUFA-diet). One group of rats received a non-lipid diet. Under all types of lipid containing diets, development of ethanol-induced hemorrhagic gastric mucosal lesions was reduced in compared with non-lipid diet. Cytoprotective effect of n-3 PUFA-E was greater than MUFA and SFA, but smaller than n-6 PUFA.

[Nature of the effects of omega-3-polyenic fatty acids on the development of acute inflammation in experimental animals]. / K voprosu o kharaktere vliianiia omega-3-polienovykh zhirnykh kislot na razvitie ostrogo vospaleniia v éksperimente.

Influence of dietary w-6 and w-3 polyunsaturated fatty acids (PUFA), monounsaturated fatty acids (MUFA) and saturated fatty acids (SFA) on development of rat paw edema induced by dextran subplantar injection was studied. Female Wistar rats the initial weight 150-160 g were bed fo four weeks diets containing as lioid components 6% butter and 3% sunflower oil (w-6 PUFA-diet), 6% butter and 3% fish oil (w-3 PUFA-diet), 6% butter and 3% olive oil (MUFA-diet) or butter (SFA-diet). One group of rats received a non-lipid diet. The development of rat paw edema was reduced under the w-3 PUFA-diet in comparison with the w-6 PUFA-diet, but more intensive then under the non-lipid diet. No differences were detected in effects on inflammation induced w-3 PUFA-, MUFA-, and SFA-diets.

[The role of polyene fatty acids in the development of acute inflammation in rats]. / Rol' polienovykh zhirnykh kislot v razvitii ostrogo vospaleniia u krys.

The effect of n6 and n3 polyunsaturated fatty acids (PUFA) on development of acute inflammation in rats has been studied. During 4 weeks male Wistar rats (initial weight 140-150 g) were on feed containing as lipid component 6% butter and 3% fish oil obtained from Sardinops sagax melanosticta (n3 PUFA-diet). The development of paw oedema induced by subplantar injection of dextran or carrageenan inhibited when the animals were on diet where prevailed n3 PUFA. In contrast, the state of paw oedema, caused by intraperitoneal administration of egg white was similarly high in rats given both n6 and n3 PUFA.

Diurnal variation of nuclear volumes and the mitotic index of cells in the adrenal zona glomerulosa of rats.

In adult male Wistar rats (200-230 g), nuclear volumes of cells in the adrenal zona glomerulosa exhibit diurnal variation with the peak values at 12 p.m.-3 a.m. and the nadir value at 12 a.m. Diurnal variation of the mitotic index is characterized by high values from 9 a.m. to 6 p.m. and low values from 12 p.m. to 6 a.m.

[Diet containing fish oil as protection against ethanol-induced lesions of the gastric mucosa in rats]. / Dieta, soderzhashchaia zhir ivaci, kak zashchita ot povrezhdeniia slizistoi obolochki zheludka krys étanolom.

Effect of dietary fish oil obtained from Sardinops Sagax malanosticta on ethanol-induced gastric mucosal lesions was studied in female Wistar rats with initial weight of 90-100 g. During three weeks, the untreated control group was fed with the basic diet containing 6% butter as a lipid component, while two test groups received olive oil or fish oil 0.2 ml/rat/day) in addition to the basic diet. In the control group, intragastric administration of 1 ml of ethanol (96 degrees) caused acute gross gastric mucosal damage (edema, vascular engorgement, and hemorrhagic erosions) in 14 of 16 rats. Supplement of olive oil decreased the number of rats with ethanol-induced gastric mucosal lesions in the group, but did not reduce the ratio of damaged area to the total area of the stomach. In contrast, rats receiving dietary fish oil showed a decrease in both the incidence and extent of mucosal lesions. It has been suggested that the protective effect of dietary fish oil on the gastric mucosa is due to a high content of eicosapentaenoic acid.

[Glycogen level and activity of carbohydrate metabolism enzymes in the liver of rats during the readaptation period after a 20-day hypokinesia]. / Soderzhanie glikogena i aktivnost' fermentov uglevodnogo obmena pecheni v readaptatsionnom periode posle 20-sutochnoi gipokinezii krys.

Content of glycogen and activity of hexokinase (HK) were similar to control value, while activity of glucose-6-phosphate dehydrogenase (G6PD) was increased in liver tissue of rats after 20 days long hypokinesia. Acute stress (or readaptation stress) was observed in the animals after discontinuation of the immobilization, which was characterized by a decrease in content of glycogen and in activity of HK and G6PD in liver tissue. These patterns studied exceeded the control values within the first week after immobilization, they became similar to controls within 10 days and decreased repeatedly at the period between 20 and 30 days. Only within 45-65 days of the readaptation period content of glycogen as well as activity of HK and G6PD were completely normalized.

[Effect of long-term hypokinesia on the androgenic system in rats]. / Vliianie dlitel'noi gipokinezii na androgennuiu sistemu krys.

Rats were immobilized in small cages for 1, 5, 10, 15, 20, 30, 45, 60 or 90 days. After exposure the weight of testes, seminal vesicles and prostate as well as the volume of cell nuclei of the reticular area of the adrenal cortex was measured. The weight of seminal vesicles and prostate diminished 1.5-2 times while that of testes decreased insignificantly. Cell nuclei of the reticular area of the adrenal cortex were enlarged during the first 5 days of hypokinesia, returning to the baseline thereafter. Cell nuclei became less than the baseline after 20 days of hypokinesia. These changes in the reticular area were associated with secretion of glucocorticoids rather than androgens.

Effect of prolonged restraint on glycogen content and activities of four enzymes of carbohydrate metabolism in the liver of rats.

Triphasic changes in glycogen content and activities of four enzymes of carbohydrate metabolism (glucose-6-phosphatase, phosphoenolpyruvate carboxykinase, hexokinase, and glucose-6-phosphate dehydrogenase) were studied in the liver of male Wistar rats exposed to 1, 5, 10, 15, 20, 30, 45, 60, 70 and 90-day movement restrain in pencil cases. It was assumed that these three phases corresponded to the alarm, resistance and exhaustion stages of Selye's general adaptation syndrome. In hypokinetic rats, however, a transition of the alarm reaction to the resistance stage was registered later, and hepatic glycogen accumulation was reduced in comparison with the standard pattern observed in chronic stress.

Adrenal cortex of rat: diurnal variation of nuclear volumes and mitotic index of cells in zona fasciculata.

Diurnal variation in nuclear volumes of cells in the adrenal zona fasciculata was observed in adult male Wistar rats (200-230 g) with a peak level at 24.00-03.00 and the lowest level at 09.00. There was found a diurnal variation in mitotic index with a peak value at 06.00-09.00 and a trough at 18.00-24.00.