Interaction of phonons at superfluid helium-solid interfaces

A new method of obtaining the interaction Hamiltonian of phonons at superfluid helium-solid interface is proposed in the work. Equations of hydrodynamic variables are obtained in terms of second quantization if helium occupies a half-space. The contributions of all processes to the heat flux from solid to superfluid helium are calculated based on the obtained Hamiltonian. The angular distribution of phonons emitted by a solid is found in different processes. It is shown that all the exit angles of superfuild helium phonons are allowed. The obtained results are compared with experimental data and with previous theoretical works.Comment: 9 pages, 3 figure

Pressure of thermal excitations in superfluid helium

We find the pressure, due to the thermal excitations of superfluid helium, at the interface with a solid. The separate contributions of phonons, $R^-$ rotons and $R^+$ rotons are derived. The pressure due to $R^-$ rotons is shown to be negative and partially compensates the positive contribution of $R^+$ rotons, so the total roton pressure is positive but several times less than the separate $R^-$ and $R^+$ roton contributions. The pressure of the quasiparticle gas is shown to account for the fountain effect in $HeI I$. An experiment is proposed to observe the negative pressure due to $R^-$ rotons.Comment: 14 pages, 4 figure

REGIONAL FEATURES OF BIFIDOBACTERIA ANTAGONISTIC ACTIVITY IN INTESTINAL MICROBIOTA OF CHILDREN LIVING IN SIBERIA

Antagonistic properties of bifidobacteria to opportunistic microorganisms in vitro and mechanism of antagonistic activity decreasing were studied and. analyzed. Great percentage of bifidobacteria regional population strains with low antagonistic activity to transitional opportunistic microorganisms is registered. It results to colonization. resistance decreasing and. requires development of the preventive probiotics therapy methods to correct

Analysis of phagoand antibiotic sensitivity of Enterobacteriaceae bacteria isolated from women of reproductive age

Pelvic inflammatory diseases occupy a special place in the structure of general morbidity, and are polymicrobial in nature with dominance of opportunistic microorganisms, in particular bacteria of the family Enterobacteriaceae. The aim was to study the composition of the vaginal microbiota in women of reproductive age with pelvic inflammatory diseases, as well as to determine the sensitivity of isolated microorganisms to antibiotics and bacteriophages. The study included 70 women of reproductive age, among them 37 were diagnosed with colpitis and cervicitis, 33 women in the comparison group (women screened for a diagnosis). Isolated microorganisms were identified by abdominoperineal methods, including the disk diffusion method to determine the sensitivity of microorganism cultures of Enterobacteriaceae family to antibiotics, and the method of crosses (evaluation of lytic activity of bacteriophages by the number of crosses) to determine the sensitivity to specific therapeutic bacteriophages. Vaginal biocenosis was characterized by deficit of lactobacilli (< 106 CFU/ml in 100 %), the presence of conditionally pathogenic microflora: bacteria of Enterobacteriaceae family, coccal flora and Candida fungi. From 60.0 to 89.3 % of Enterobacteria strains were resistant to aminoglycosides and quinolones, but also had a low level of sensitivity to therapeutic bacteriophages. The obtained data indicate the reduction of colonization resistance of vaginal mucosa in pelvic inflammatory diseases and specify the need to use medicinal drugs only under medical supervision to prevent clinically significant drug resistance

DETECTION OF GENETIC DETERMINANTS OF PATHOGENICITY OF STRAINS OF KLEBSIELLA SPP. ISOLATED FROM THE INTESTINAL BIOTOPE OF CHILDREN WITH FUNCTIONAL GASTROINTESTINAL DISORDERS

Functional gastrointestinal disorders (FGID) are one of the most common problems in children of the first year of life. The aim of the study was to assess the pathogenic potential of Klebsiella spp. strains, isolated from the colon in children of the first year of life with FGID. Material for the study included 61 coprological samples. The biological material was divided into comparison groups, depending on the type of Klebsiella excreted at a concentration of 105–108 CFU/g: 1st – with vegetation in the colon K. pneumoniae (n = 30); 2nd – with vegetation K. oxytoca (n = 31). Bacteriological study composition of the intestinal contents was carried out according to the Industry standard “Protocol of management of patients. Intestinal dysbiosis” (2003). Identification was carried out according to generally accepted schemes using commercial test systems for biochemical identification of bacteria. Statistical data processing was performed using licensed applications “MS Office Excel 2003 for Windows 7”. The data on the quantitative and qualitative changes in the composition microbiota in the comparison groups were obtained. The results of detection genetic determinants of pathogenicity in the samples of Klebsiella of two species show that among the strains of Klebsiella spp., vegetating in the intestines of children as a component of an allochthonous microbiota, a sufficiently high and virulent potential can be concentrated. Detection of pathogenicity genes in bacteria of the genus Klebsiella will expand and deepen the problem of finding the structures of adaptation of strains of bacteria that cause FGID in children of the first year of life

Microorganisms associated with bacterial vaginosis: diversity and clinical and diagnostic significance

Bacterial vaginosis (BV) is the most common infectious non-inflammatory disease in women of reproductive age. The key feature of BV is that in the  absence of a specific pathogen, the disease develops against the background of vaginal biotope dysbiosis. According to the opinion of some authors, initially, the main role of BV in the pathogenesis was assigned to the species G. vaginalis. However, using of molecular methods made it possible to significantly expand the range of microorganisms found in women with BV, and to identify Gardnerella vaginalis, Atopobium vaginae, Mobiluncus spp., Prevotella spp. as the primary causative agents of BV. A number of studies have confirmed the sexual transmission of BV pathogens, with a new sexual partner being significant risk factors for episodic BV, and sexual contact with the same partner without using barrier methods of contraception for recurrent BV. At the same time, BV-associated bacterias  rarely exist as planktonic forms of one species, more often, they thrive in complex polymicrobial communities surrounded by an extracellular matrix, the so-called biofilms. In patients with BV, biofilms are detected in 90% of cases. G. vaginalis and Prevotella bivia are widespread in women with BV and, being the primary colonizers, create a bacterial biofilm, to which secondary colonizers can subsequently join, including A. vaginae, Sneathia spp. and potentially other BVABs. The resistance of bacterias in the biofilm to antimicrobial drugs is 1000 times higher than of planktonic forms, which can lead to chronicity of the infectious process and torpid course of the disease.The aim of this review was analyzing of modern studies on the prevalence, characteristics of opportunistic microorganisms associated with BV, to present their clinical and diagnostic significance and role in the pathogenesis of  diseases