Optical and magnetic properties of the ground state of Cr3+ doping ions in REM3(BO3)4 single crystals.

New data about the state of Cr3+ doping ions in a single crystal of YGa3(BO3)4 have been obtained by studying different methods. Using electron paramagnetic resonance, it was found that the Cr3+ ions substitute the trivalent gallium ions. The obtained spin Hamiltonian parameters of the Cr3+ ions in the YGa3(BO3)4 single crystal (g = 1.9743 ± 0.0004; D = -0.465 ± 0.001 cm-1; E = -0.013 ± 0.001 cm-1) were analyzed and compared with those in TmAl3(BO3)4, EuAl3(BO3)4, and YAl3(BO3)4. The deviation of the Z-axis in the spectrum from the crystallographic axis С3 is 1,7 degrees in YGa3(BO3)4. In situ X-ray diffraction was used to study the structural and elastic properties of huntite-type borates in the temperature range of RT-1073 K. In the radioluminescence (RL) spectra, the Cr3+-related emission bands were observed in the red wavelength range, and the presence of other defect-related bands was also registered in some cases. Thermally stimulated luminescence (TSL) glow curves were acquired over a wide temperature range, and the trap depths of the most prominent bands were calculated. The 11B NMR spectra show that two nonequivalent spectral components exist for BO3 structural elements.

[Oral cavity microflora in patients with non-specific ulcerative colitis and Crohn's disease].

Results of study of microecological disorders in oral cavity of patients with non-specific ulcerative colitis (NSUC) and Crohn's disease (CD) and control subjects (patients with hypertension). Condition of mucosa was assessed on the basis of morphological data and electrophoretic mobility of cell nuclei, whereas structure of microbiocenosis and metabolic activity of microflora--on the basis of saliva bacterial culture and contents and profile of volatile fat acids in it. Detection rate of negative charge of the cell nuclei (decrease of functional activity of epithelium) was significantly higher in patients with NSUC and CD (66.6%) compared with controls (10%). This fact was directly related with hypercolonization of oral cavity by Gram-negative microflora. Lesions of mucosa which are characteristic of NSUC and CD and determined by pathologic immune mechanisms correlated with quantity of pathogenic microflora (Staphylococcus aureus and Candida). Marked differences of chromatograms' patterns were observed in patients with NSUC and CD indicating the suppression of anaerobic microflora in patients with CD and hypercolonization of oral cavity by anaerobic microflora in majority of patients with NSUC.

Peculiarities of excited state structure and photoluminescence in Bi(3+)-doped Lu(3)Al(5)O(12) single-crystalline films.

Single-crystalline films of Lu(3)Al(5)O(12):Bi, prepared by the liquid phase epitaxy method from the melt-solution based on Bi(2)O(3) flux, have been studied at 4.2-400 K by time-resolved luminescence spectroscopy methods. Their emission spectra consist of two types of bands with strongly different characteristics. The ultraviolet emission band consists of two components, arising from the electronic transitions which correspond to the [Formula: see text] and [Formula: see text] transitions in a free Bi(3+) ion. At low temperatures, mainly the lower-energy component of this emission is observed, having the decay time∼10(-3) s at T<100 K and arising from the metastable (3)P(0) level. At T>100 K, the higher-energy emission component appears, arising from the thermally populated emitting (3)P(1) level. The visible emission spectrum consists of two dominant strongly overlapped broad bands with large Stokes shifts. At 4.2 K, their decay times are ∼10(-5) s and decrease with increasing temperature. Both of the visible emission bands are assumed to have an exciton origin. The lower-energy band is ascribed to an exciton, localized near a single Bi(3+) ion. The higher-energy band shows a stronger intensity dependence on the Bi(3+) content and is assumed to arise from an exciton localized near a dimer Bi(3+) center. The origin and structure of the corresponding excited states is considered and the processes, taking place in the excited states, are discussed.

Condensation of a vapor bubble in submicrometer container.

Condensation of a spherically symmetric submicrometer size vapor bubble is studied using diffuse interface hydrodynamic model supplemented by the van der Waals equation of state with parameters characteristic for argon. The bubble, surrounded by liquid, is held in a container of constant volume with temperature of the wall kept fixed. The condensation is triggered by a sudden rise of the wall temperature. We find that in the same container and subjected to a similar increase of the wall temperature the condensation process is totally different from the opposite process of droplet evaporation. In particular, the rapid change of the wall temperature excites the wave, which hits the interface and compresses the bubble, leading to a considerable increase of the temperature inside. The condensation of the submicrometer size bubble takes tens of nanoseconds, whereas evaporation of the same size droplet lasts roughly 50 times longer. In contrast to evaporation the condensation process is hardly quasistationary.

Minimization of the Renyi entropy production in the space-partitioning process.

The spontaneous division of space in Fleming-Viot processes is studied in terms of non-extensive thermodynamics. We analyze a system of n different types of Brownian particles confined in a box. Particles of different types annihilate each other when they come into close contact. Each process of annihilation is accompanied by a simultaneous nucleation of a particle of the same type, so that the number of particles of each component remains constant. The system eventually reaches a stationary state, in which the available space is divided into n separate subregions, each occupied by particles of one type. Within each subregion, the particle density distribution minimizes the Renyi entropy production. We show that the sum of these entropy productions in the stationary state is also minimized, i.e., the resulting boundaries between different components adopt a configuration which minimizes the total entropy production. The evolution of the system leads to decreasing of the total entropy production monotonically in time, irrespective of the initial conditions. In some circumstances, the stationary state is not unique-the entropy production may have several local minima for different configurations. In the case of a rectangular box, the existence and stability of different stationary states are studied as a function of the aspect ratio of the rectangle.

Evaporation of a thin liquid film.

Evaporation of a thin (submicrometer size) liquid film confined between two solid substrates is studied using diffuse interface hydrodynamic model supplemented by the van der Waals equation of state. The time and space evolution of the basic thermodynamic quantities such as temperature, density, entropy, chemical potential, and entropy production is presented. The values of numerical parameters chosen correspond to those of argon. The time and space scales studied range from picoseconds to microseconds and from nanometers to micrometers correspondingly.

Evaporation of a sub-micrometer droplet.

Evaporation of a spherically symmetric sub-micrometer size liquid droplet is studied using a diffuse interface hydrodynamic model supplemented by the van der Waals equation of state with parameters characteristic for argon. The droplet, surrounded by saturated vapor, is held in a container with the temperature of the walls kept fixed. The evaporation is triggered by a sudden rise of the temperature of the walls. Time and space evolution of the basic thermodynamic quantities is presented. The time and space scales studied range from picoseconds to microseconds and from nanometers to micrometers, respectively. We find that the temperature and chemical potential are both continuous at the interface on the scale larger than the interfacial width. We find that at long times the radius R of the droplet changes with time t as R(2)(t) = R(2)(0) - 2tkappa(v)(T(w) - T(l))/ln(l), where kappa(v) is the heat conductivity of the vapor, n(l) and T(l) are the density and the temperature of liquid inside the droplet, respectively, l is the latent heat of transition per molecule, and T(w) is the temperature of the ambient vapor.

[Numerous anomalously located chords in the apical part of the left ventricle--etiological and pathogenetical factors of ischemic stroke in young people]. / Mnozhestvennye anomal'no raspolozhennye khordy na verkhushke levogo zheludochka--étiologicheskii i patogeneticheskii faktory ishemicheskogo insul'ta u lits molodogo vosrasta.

The article presents the case of ischemic stroke with enough favorable outcome in the patient of 19 y.o. The cause of this stroke was determined. It was "a web" of numerous anomalous located chords in the apical part of left ventricle.

[Effect of a nibentan derivative LKhT53-91 on the heart electrophysiological parameters]. / Vliianie proizvodnogo nibentana LKhT53-91 na élektrofiziologicheskie parametry serdtsa.

The compound LKhT5391 (a derivative of nibentan) affects the electrophysiological cardiac parameters to a lower extent than does nibentan. Administered in an effective antiarrhythmogenic dose (comparable with the effective dose of nibentan), LKhT5391 produces a less pronounced and shorter negative chronotropic action than does nibentan. The negative dromotropic effect of the compound studied is manifested only in the atrioventricular node, while not influencing conductivity through the atria and ventricles.

Solitonlike propagation in photorefractive crystals with large optical activity and absorption.

We have found analytical solutions of the light propagation equations in photorefractive materials with strong optical activity and absorption. These solutions show the occurrence of breathing solitons in sillenite crystals with strong optical activity and absorption in two particular orientations with respect to the external electric field. The absorption is decreasing the soliton intensity with the propagation distance (which set a limit in the soliton channel length), is increasing the breathing period, and is changing the soliton width (in inverse relations, at low and high intensities). Our experimental results confirm the analytical solutions and the numerical simulations, as well as the importance of the optical activity and absorption in solitonlike propagation.

Seroprevalence of Helicobacter pylori infection in Siberia.

BACKGROUND: Despite many population-based epidemiological studies of Helicobacter pylori prevalence in different parts of the world, Russia still represents a 'blank spot' in this map. The aims of the present study were to evaluate the seroprevalence of H. pylori infection among the population of Siberia and to assess whether there is an association between abdominal symptoms and H. pylori positivity in our population. METHODS: Six hundred and forty-nine adults from five regions of Siberia and the Far East, and 79 children and adolescents from Novosibirsk participated in the study. Antibodies against H. pylori (IgG) were detected in serum using ELISA. RESULTS: The total percentage of infected adults varied from 70% to 92% depending on the region, and was somewhat lower in three populations living to the north of the 60th latitude compared with those under the 60th latitude. A lack of association was found between the presence of H. pylori and the gender, age and abdominal symptoms. Almost maximum prevalence of H. pylori infection occurred by 30 years of age with only a minor increase in older age groups. Half the children were infected with H. pylori by the age of 15. CONCLUSIONS: Helicobacter pylori infection is widespread among the Siberian populations with some trend in its prevalence to decrease northward. In Siberia age-specific prevalence rates of H. pylori infection are similar to those usual for developing countries.

[Susceptibility of beta-hemolytic streptococci to antibiotics and alternative drugs]. / Chuvstvitel'nost' beta-gemoliticheskikh streptokokkov k antibiotikam i al'ternativnym preparatam.

Antibiotic susceptibility of the circulating beta-hemolytic streptococci of serogroups A, B, C and G isolated from healthy and sick children and adults within 1987-1996 (more than 900 cultures) was studied. It was shown that the MICs of betalactam antibiotics did not change (within the susceptibility levels) with respect to the serogroup A, C and G streptococci. The number of the strains resistant to erythromycin and lincomycin increased the same as the frequency of the strains simultaneously resistant to chloramphenicol, tetracycline and gentamicin. Tomicid and solkarmon, drugs alternative to antibiotics, were found to be active against the above streptococci groups and efficient in the treatment and prophylaxis of streptococcoses. A suggestion that betalactams are not safe in the treatment of the toxic shock syndrome due to the group A streptococci is discussed.

Developmental neurotoxicity and immunotoxicity of 2,4,6-tribromophenol in Wistar rats.

Pregnant Wistar rats were exposed to 2,4,6-Tribromophenol (TBP) by whole body inhalation (0, 0.03, 0.1, 0.3, 1.0 mg/m3, 24 hr/day, 7 days/weeks, from day 1 to 21 of gestation). Significant decreases in orientation reactions were noted at concentrations of 1.0 mg/m3 (p < 0.05) in the open field test. Nonsignificant trends (p > 0.05) toward decreased horizontal movement and emotionality in the open field and increased electrical impulse skin pain threshold (SPT) were observed. No significant exposure-related differences in the nonspecific immunological status (phagocytosis and blood anti-microbe activity) of pregnant rats were seen after the exposure. Preimplantation and postimplantation embryo losses were significantly increased in a dose-dependent manner and were seen in all treated groups except the lowest concentration (0.03 mg/m3) group. Signs of retarded fetal skeletal development and increased frequencies of visceral abnormalities were found at concentrations of 0.1 and 1.0 mg/m3. Significant effects were found for lower incisor eruption and ear unfolding at a concentration of 0.3 mg/m3. The grooming behavior of 30-day old male progeny was significantly less than control in all experimental groups. Grooming behavior in female subjects exposed to a concentration of 0.3 mg/m3 and emotionality in subjects exposed to a concentration of 1 mg/m3 were decreased significantly. At 60 days of age emotional reactions were significantly decreased in female subjects from the 0.03, 0.3 and 1.0 mg/m3 groups. SPT was significantly increased in the 1 mg/m3 group for both male and female pups. Thus, evidence of CNS depression influence of TBP both in maternal and offspring groups was found. The NOEL (No Observed Effect Level) for developmental neurotoxicity is thus < 0.03 mg/m3, and the NOEL for maternal neurotoxicity is 0.3 mg/m3. These results suggest that exposure to TBP for 24 hr/day throughout gestation may cause developmental neurotoxicity, embryotoxicity and fetotoxicity, but not immunotoxicity.

[The interrelations of mucosal epithelial cells with microbes--intracellular parasites]. / O zaimotnosheniia épitelial'nykh kletok slizistykh obolochek s mikrobami--vnutrikletochnymi parazitami.

On the basis of information at hand, it can be concluded that there are principal limits on the capture of bacteria by epithelial cells in the gastrointestinal tract and other cavities. Although entry is, however, a result both of bacteria and epithelial cells, it is frequently induced by parasite-directed endocytosis and may also accompanied by passive entry of nonpathogenic bacteria. The induction of parasite-induced endocytosis should be regarded as a consequence of a fundamental concept in biology, namely: molecular and cellular recognition wherein bacterial adhesion to the host's cell receptors is of great importance. In this connection, discussion covers the origin of corresponding receptors. The authors share the opinion in that epithelial cells, those of the gastrointestinal tract in particular, are part of the human common mucosal immune system.

Control of Vascular Sap pH by the Vessel-Associated Cells in Woody Species (Physiological and Immunological Studies).

In Robinia wood, the vessel-associated cells form a continuous sleeve around the vessels. Variations in pH of the solution perfused through the vessels during the annual cycle and the opposing effects of carbonyl cyanide-m-chlorophenylhydrazone and fusicoccin on this pH value indicate that some living cells of the wood are involved in the control of vascular sap pH and that this control fluctuates with the seasons. The immunolocalization of the plasma membrane HT+-ATPase in Robinia wood was studied by the immunogold-silver-staining technique using an antibody raised against a conserved stretch of the cytoplasmic domain of the H+-ATPase. The immunostaining is much stronger in vessel-associated cells than in other living cell types (ray and axial parenchyma elements) of the secondary xylem. Our data show an efficient involvement of this cell type in the control of vascular sap pH.