Phenotypes of pseudomonas aeruginosa strains, isolated in surgical clinics

After studying of 83 strains of P. aeruginosa we revealed the phenotypic heterogeneity (in phospholipase activity, biofilm-forming capacity, resistance to antibiotics et al.) of bacterial populations both in different departments within one multi-specialized clinic and in different surgical clinics. We determined, that strains, isolated from intensive care unit, have the largest number of expressive pathogenic factors and high multiple drug resistance. The likeness or difference of phenotypic characteristics of P. aeruginosa, which is inductive, don't let us estimate definitely the possibility of strain migration from the intensive care unit into another departments of the multi-specialized clinic, as we don't know clearly if the heterogeneity of population of P. aeruginosa is conditioned by modified variability or its differences are fixed in the genome. Permanently preserved conditions and typical contingent of patients in specialized departments contribute to the forming of profiled phenotypes among the isolated strains.В результате изучения 83 штаммов P. aeruginosa, выявлена фенотипическая гетерогенность (по фосфолипазной, пленкообразующей способности, антибиотикорезистентности и др.) популяций синегнойной палочки в различных отделениях одного многопрофильного, а также в разных хирургических стационарах г. Перми. Установлено, что штаммы, изолированные из ОРИТ, характеризуются наиболее широким набором экспрессируемых факторов патогенности и выраженной множественной лекарственной устойчивостью. Сходство или различие фенотипических характеристик изолятов P. aeruginosa, проявление которых в значительной степени индуцибельно, не позволяют однозначно оценить вероятность миграции штаммов, изолированных в ОРИТ, в другие отделения многопрофильного хирургического стационара, поскольку не ясно, обусловлена ли гетерогенность популяций синегнойной палочки модификационной изменчивостью или их отличия закреплены в геноме. Перманентно сохраняющиеся условия и типичные контингенты специализированных отделений способствуют формированию среди изолируемых в них культур профилированных фенотипов

Modeling of Crack Formation after Pulse Heat Load in ITER-grade Tungsten

The one-dimensional numerical simulations of the deformation during and after the pulsed heat load are carried out for tungsten manufactured according to ITER specifications. The calculations for stress-relieved tungsten demonstrated the cracking at temperatures above ductile-to-brittle transition temperature. The features of the stresses caused by thermal expansion are discussed

Impact of neutron radiation on the viability of tumor cells cultured in the presence of boron-10 isotope

Objective: to investigate the impact of a neutron beam formed with the accelerator-based epithermal neutron source designed at the G.I. Budker Institute of Nuclear Physics (INP) on the viability of human and animal tumor cells cultured in the presence of boron-10 isotope.Material and methods. Human U251 and T98G glioma cells and Chinese hamster CHO-K1 and V-79 cells were incubated at various concentrations in the culture medium containing 10B-enriched L-boronophenylalanine. The cells were irradiated with a neuron beam using the accelerator-based epithermal neuron source. A clonogenic assay was used to evaluate the viability of the irradiated cells. The absorbed doses obtained from elastic scattering of fast neutrons by substance nuclei and the doses obtained from boron neutron capture were calculated using the NMS code. The absorbed doses of gamma-radiation were measured with a mixed radiation dosimeter.Results. The viability of boron-containing and intact human U251 and T98G cell lines and Chinese hamster CHO-K1 and V-79 cells was analyzed after neutron beam radiation. Irradiation of all four cell lines were cultured in the presence of 10B was shown to reduce their colony-forming capacity compared with the control. Elevated boron levels in the culture medium resulted in a significant decrease in the proportion of survived cells. Radiation had the most pronounced impact on the proliferative capacity of the human U251 glioma cell lines.Conclusion. The cultures of human tumor cells and mammalian cells demonstrated that the neutron beam formed with the accelerator-based epithermal neutron source designed at the INP, was effective in reducing the viability of tumor cells in the presence of 10

Calculation of Cracking inTungsten Manufactured According to ITER Specifications Under Pulsed Heat Load

A mathematical model of surface cracking under pulsed heat load was developed. The model correctly describes a smooth brittle–ductile transition. The elastic deformation is described in a thin-heated-layer approximation. The plastic deformation is described with the Hollomon equation. The time dependence of the deformation and stresses is described for one heating–cooling cycle for a material without initial plastic deformation.The model can be applied to tungsten manufactured according to ITER specifications. The model shows that the stability of stress-relieved tungsten deteriorates when the base temperature increases. This proved to be a result of the close ultimate tensile and yield strengths. For a heat load of arbitrary magnitude a stability criterion was obtained in the form of condition on the relation of the ultimate tensile and yield strengths