Simple model of the rf noise generated by multipacting electrons

A simplified analytical model is developed to predict the spectrum of electric current induced by the multipacting electrons between two parallel electrodes exposed to an rf voltage of fixed amplitude. The model is based on the resonant multipactor theory and makes it possible to calculate the relative spectral amplitudes of electric current at different harmonics and sub-harmonics of the applied rf frequency. The theoretical predictions are confirmed by numerical simulations of multipactor inside a rectangular waveguide. Specifically it is seen that the relative height of the spectral peaks decreases with increasing gap height

Role and responsibilities of a teacher in the lifelong learning sector

Teaching is quite challenging and demanding alongside with many other careers. The main role of every teacher is to involve and engage your students in learning activities. An appropriate level of language, appropriate terms understandable to your students will motivate them to learn mor

DETECTION OF PATHOGENICITY GENES ENCODING ABILITY TO TOXIGENESIS IN ESCHERICHIA COLI ISOLATED FROM THE CHILDREN INTESTINAL BIOTOPE

Shiga toxins (stxs) are the virulence factor of enterohemorrhagic Escherichia coli (EHEC). Shiga toxin-producing Escherichia coli has been recognized as an important food-borne pathogen that causes severe diseases such as a hemolytic uremic syndrome (HUS). Provides information about the species composition of the major opportunistic organisms that inhabit this biotope. Using polymerase chain reaction (PCR) 96 strains of E. coli were examined for the presence of genes stx1 and stx2 coding the ability to toxigenesis. They were isolated from the children with functional disorders of the gastro-intestinal tract. Both pathogenicity genes present in the genome of E. coli with normal enzyme activity more often (stx1 in 24,2 % of genomes, stx2 in 9,1 %). The presence of stx1 and stx2 genes in different biochemical variants of E. coli allows to ascertain the fact of presence of a potentially pathogenicity reservoir in non-pathogenic forms of E. coli. Intestinal microflora is integral part of each individual. Further studying of its functions, the states interfering qualitative and quantitative composition of microorganisms, colonizing human gastrointestinal tract, as well as the pathogenic potential

Microecological and associative structure of intestinal biocenosis in children with functional gastrointestinal disorders

The article is devoted to one of actual problems of gastroenterology - study of microbiocenosis of gastrointestinal tract in functional disorders. Functional gastrointestinal disorders (FGID) or minimal dysfunctions of digestion are frequent in the first months of child's life and provoke anxiety both in parents and in pediatricians. Aim: to explore the microbial landscape and the associative structure of the microbiota of the large intestine in children with functional disorders of the gastrointestinal tract. Subjects and methods: Intestinal microbiota composition of 225 children with functional gastrointestinal disorders and 100 healthy children was studied using bacteriological method. Results. The 88.4 % frequency of detection of intestinal eubiosis disorders is discussed. Information is provided on the species composition of the major opportunistic organisms that inhabit this biotope. According to the results, decrease of bifidobacteria amount in structure of large intestine microbiota increases rate of detection of opportunistic microorganisms - predominantly, Klebsiella genus bacteria and Staphylococcus aureus. The intestinal microbial community is dominated by multicomponent transient association. The frequency of detection of pathogenic Staphylococcus in children under one year is discussed in detail. Conclusions. A distinctive feature of the intestinal biocenosis microecological status is significantly greater spread of enterococci than in healthy children, which can be a risk for the emergence of strains with the presence of a number of pathogenecity factors that cause infectious processes

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 some genes encoding pathogenicity factors in the typical isolates of Escherichia coli

Using polymerase chain reaction 316 strains of E. coli (strains with normal enzymatic activity, strains with weak enzymatic activity and strains with hemolytic activity) were examined for the presence of pathogenicity genes. They were isolatedfrom healthy children and children with functional disorders of the gastro-intestinal tract. The studies have shown that strains of Escherichia coli have pathogenic potential, as evidenced by the presence of genetic pathogenicity markers in them

Detection of genetic markers of pathogenicity factors at associative symbiosis of Klebsiella spp. and Staphylococcus aureus autostrains, isolated from infants

The article presents the results of detection of genetic determinants of pathogenicity in 120 Klebsiella strains (Klebsiella pneumoniae, Klebsiella oxytoca) and 48 Staphylococcus aureus strains isolated from the intestinal habitat of infants with intestinal dysbiosis. Registration of the investigated determinants in Klebsiella spp. autostrains DNA, which are non-clinical isolates, indicates the circulation of pathogenicity factors and, consequently, their possible causation in the formation of intestinal dysbiosis in infants

DETECTION OF CERTAIN GENETIC MARKERS OF THE PATHOGENIC FACTORS IN AUTOSTRAINS KLEBSIELLA SPP. IN INFANTS

The article presents the results of detection of genetic determinants of pathogenicity in 44 strains of Klebsiella (Klebsiella pneumoniae, Klebsiella oxytoca), isolated from the intestinal habitat of infants with intestinal dysbiosis. The presence of the uge gene was detected in 92 % of cases in K. oxytoca and in 90 % of K. pneumoniae. Kfu gene was detected twice as frequent (30 %) in K. pneumoniae strains than in K. oxytoca (12,5 %); bfp gene was detected in K. oxytoca 5 times more frequently (25 %) than in K. pneumoniae (5 %), as well as stx 1 - 29,2 % and 15 %, correspondingly. The presence of stx 2 gene wasn't recorded in any of the DNA samples. Registration of investigated determinants in DNA of Klebsiella spp. autostrains which are non-clinical isolates indicates pathogenicity factors circulation among them and therefore the risk of the formation of intestinal dysbiosis in children

Invasive mosquito species Aedes albopictus and Aedes aegypti on the Black Sea coast of the Caucasus: genetics (COI, ITS2), Wolbachia and Dirofilaria infections

The area of invasive species Aedes albopictus and Aedes aegypti is expanding. Precise identification and understanding of the genetic diversity of invasive mosquito populations allows us to develop appropriate control methods. Endosymbiotic bacterium Wolbachia pipientis has different effects on their arthropod hosts and can influence the transmission and spread of the pathogens. The objective of the presented study was molecular-genetic identification of the Aedes mosquitoes collected in sampling sites on the Black Sea coast from 2007 to 2017; determination of genetic variability of Ae. aegypti, Ae. albopictus and their symbiotic bacteria Wolbachia; assessment of mosquitoes ability to be infected and to spread parasitic Dirofilaria. Another objective was obtaining the genetic characteristic of laboratory strain Ae. aegypti IMPITM. We investigated two markers of nuclear and mitochondrial DNA from Ae. albopictus and Ae. aegypti and compared them to DNA from Ae. cretinus and Ae. koreiсus sympatrically inhabiting the territory, as well as to one of Ae. aegypti from a laboratory line. The study of nuclear and mitochondrial DNA revealed a low level of variability in the invasive mosquitoes Ae. albopictus and Ae. aegypti collected at different collection sites and in different years. More than a half of Ae. albopictus were infected with Wolbachia, two strains of bacteria, wAlbA and wAlbB, occur in the Ae. albopictus population on the Black Sea coast. Total infection of Ae. aegypti and Ae. albopictus with dirofilariae was 1.8 %. Dirofilaria immitis was found only in mosquito abdomen, larvae of infective stage L3 were not found. D. repens larvae developed to the infective stage in the mosquitoes of both species

Результаты микроимпульсной циклофотокоагуляции у пациентов с ранними стадиями первичной открытоугольной глаукомы

PURPOSE. To evaluate the capabilities of micropulse transscleral cyclophotocoagulation (MP-TSCPC) in patients with early stages of glaucoma.METHODS. The study included 38 patients with early stages of primary open-angle glaucoma who underwent MP-TSCPC with SUPRA 810 (“Quantel Medical”, France) as primary surgical treatment. The follow-up period averaged 17±11 months (from 6 to 30 months). The Kaplan-Meier scale was used to assess the cumulative success of laser treatment.RESULTS. The postoperative period was uneventful. One month after MP-TSCPC a  significant hypotensive  effect was  observed,  averaging  41.5%  from  the  baseline.  After 6 months, the hypotensive effect continued to  persist  and averaged 36.1%. By 12 months, the hypotensive effect remained stable, IOP averaged 16.0±3.5 mm Hg, which was 31% from the baseline. No changes in best corrected visual acuity (BCVA) were detected during the observation period. Target intraocular pressure (IOP) was achieved in all cases. Optical coherence tomography and perimetry findings remained stable or improved.CONCLUSION. MP-TSCPC in patients  with  early  stages  of glaucoma leads to a pronounced stable hypotensive  effect during the follow-up period, averaging 31%  (from  20% to 50%). An improvement in the quality of life was noted due to the cease or reduction in the number of instillations. Monitoring of patients continues in order to develop practical recommendations for the indications and regimens of MP-TSCPC in the early stages of glaucoma.ЦЕЛЬ. Изучить возможности транссклеральной микроимпульсной  циклофокоагуляции   (мЦФК)   у   пациентов с ранними стадиями глаукомы.МЕТОДЫ. 38 пациентам с ранними стадиями первичной открытоугольной глаукомы  была  выполнена  мЦФК в качестве первичной хирургической процедуры на приборе SUPRA 810, (Quantel Medical, Франция). Срок наблюдения составил в среднем 17±11 месяцев (от 6 до 30 месяцев). Для оценки совокупного успеха лазерного лечения использовалась шкала Каплана-Мейера.РЕЗУЛЬТАТЫ. Послеоперационный период проходил ареактивно. Через 1 месяц после мЦФК отмечен выраженный гипотензивный эффект, который составил в среднем 41,5% от исходного. Через 6 месяцев гипотензивный эффект продолжал сохраняться и составил  в среднем 36,1%. К 12 месяцам наблюдения стабильный гипотензивный эффект сохранялся, ВГД составило в среднем 16,0±3,5 мм рт.ст, что в  среднем  составило 31% от исходного. За период наблюдения снижения остроты зрения не выявлено.  Целевое  ВГД  достигнуто во всех случаях. Показатели оптической когерентной томографии и периметрии оставались стабильными.ЗАКЛЮЧЕНИЕ. мЦФК у пациентов с ранними стадиями глаукомы приводит к выраженному гипотензивному стабильному эффекту в течение всего срока наблюдения до 31% (от 20% до 50%). Отмечено улучшение качества жизни в связи с отказом или сокращением количества инстилляций. Для выработки практических рекомендаций по показаниям и режимам мЦФК на ранних стадиях глаукомы проводится дальнейшее наблюдение за пациентами