Оценка неравномерности упругих свойств листов из закрытоячеистых пенополиолефинов акустическим методом

The widespread use of polyolefin foams in strategically important industries is due to their high thermal, sound and vibration insulation properties. The aim of the work was to evaluate the non-uniformity of elastic properties over the area of sheets of polyolefin foams of various types using the acoustic non-contact shadow amplitude method of testing and confirmation by the structural analysis method.The article presents the developed installation and a new method of non-contact acoustic testing of sheets made of closed-cell polyolefin foams based on recording the amplitude of the pulse that passed through the sheet and allowing to assess to the unevenness of its elastic properties during scanning. Studies of uneven elastic properties were carried out on sheets of closed-cell polyolefin foams of the ISOLON 500 and ISOLON 300 brands which differ in material and manufacturing technology (technique of cross-linking, method and multiplicity of foaming).It is shown that the absolute amplitude of the signal and its spread relative to the average value is affected by the structure of the foam polyolefin material and its heterogeneity over the area of the studied sheet determined by the production technology which is confirmed visually using microscopy.Studies have shown the effect on the indications unevenness of the method of obtaining and the apparent density of the material. It is shown that the most uneven elastic properties and structure belong to sheets of polyolefin foam obtained by chemical cross-linking technology (the unevenness of Δ was 6.5 %). Among the physically cross-linked sheets of polyolefin foam the most uniform in structure and elastic properties are samples made of ethylene vinyl acetate with Δ = 3.8 %, as well as sheets with a high foaming rate (Δ = 3.9 %). The unevenness of structure of the studied sheets of polyolefin foams was confirmed by optical microscopy of sections in two mutually perpendicular directions.Широкое использование пенополиолефинов в стратегически важных отраслях промышленности обусловлено их высокими тепло-, звуко- и виброизоляционными свойствами. Целью работы являлась оценка неравномерности упругих свойств по площади листов пенополиолефинов различных типов с использованием акустического бесконтактного теневого амплитудного метода контроля и подтверждением методом структурного анализа.Разработаны установка и новая методика бесконтактного акустического контроля листов из закрытоячеистых пенополиолефинов, основанная на регистрации амплитуды импульса, прошедшего сквозь лист, и позволяющая оценить неравномерность его упругих свойств в процессе сканирования. Исследования неравномерности упругих свойств проведены на листах из закрытоячеистых пенополиолефинов марки ISOLON 500 и ISOLON 300, различающиеся материалом и технологией изготовления (способ сшивки, метод и кратность вспенивания).Показано, что на абсолютную амплитуду сигнала и её разброс относительно среднего значения влияет структура материала пенополиолефина и её неоднородность по площади исследуемого листа, определяемая технологией производства, что подтверждено визуально с использованием микроскопии. Исследования показали влияние на неравномерность показаний способа получения и кажущейся плотности материала. Показано, что наиболее неравномерные упругие свойства и структуру имеют листы из пенополиолефинов, полученных по технологии химической сшивки (неравномерность Δ составила 6,5 %). Из физически сшитых листов пенополиолефинов наиболее равномерными по структуре и упругим свойствам являются образцы, изготовленные из этиленвинилацетата с Δ = 3,8 %, а также листы с высокой кратностью вспенивания (Δ = 3,9 %). Неравномерность структуры исследованных листов пенополиолефинов подтверждена оптической микроскопией срезов в двух взаимно перпендикулярных направлениях

QM/MM description of newly selected catalytic bioscavengers against organophosphorus compounds revealed reactivation stimulus mediated by histidine residue in the acyl-binding loop

© 2018 Zlobin, Mokrushina, Terekhov, Zalevsky, Bobik, Stepanova, Aliseychik, Kartseva, Panteleev, Golovin, Belogurov, Gabibov and Smirnov. Butyrylcholinesterase (BChE) is considered as an efficient stoichiometric antidote against organophosphorus (OP) poisons. Recently we utilized combination of calculations and ultrahigh-throughput screening (uHTS) to select BChE variants capable of catalytic destruction of OP pesticide paraoxon. The purpose of this study was to elucidate the molecular mechanism underlying enzymatic hydrolysis of paraoxon by BChE variants using hybrid quantum mechanical/molecular mechanical (QM/MM) calculations. Detailed analysis of accomplished QM/MM runs revealed that histidine residues introduced into the acyl-binding loop are always located in close proximity with aspartate residue at position 70. Histidine residue acts as general base thus leading to attacking water molecule activation and subsequent SN2 inline hydrolysis resulting in BChE reactivation. This combination resembles canonical catalytic triad found in active centers of various proteases. Carboxyl group activates histidine residue by altering its pKa, which in turn promotes the activation of water molecule in terms of its nucleophilicity. Observed re-protonation of catalytic serine residue at position 198 from histidine residue at position 438 recovers initial configuration of the enzyme's active center, facilitating next catalytic cycle. We therefore suggest that utilization of uHTS platform in combination with deciphering of molecular mechanisms by QM/MM calculations may significantly improve our knowledge of enzyme function, propose new strategies for enzyme design and open new horizons in generation of catalytic bioscavengers against OP poisons

Reconstruction of recombination sites in genomic structures of the strains of genotype 6 of hepatitis C virus

The encoded portion of the complete genomes of 46 strains of the genotype 6 of hepatitis C virus through bioinformatics RDP programs complex group of 6 recombinants strains was identified, in which 7 recombination sites were fixed. Strains correspond to the three-recombinant HCV subtypes: 6a, 6b and 61. For each of the identified recombinant we defined parent strains from which they can be obtained. Three recombinants were obtained from parent strains of the same subtype (homologous inside subgenotypic recombination). For the remaining three recombinants parent strains were members of three different subtypes (between subgenotypic recombination).In one strain we identified a unique recombination site in a highly conservative NS3 gene. Most of the recombination sites occurred in the region of the structural genes C, E1 and E2, and in the area of non-structural genes NS5a and NS5b.In the recombinant strain DQ480518-6a two recombination site were identified. One site is located in the structural and nonstructural genes (E2 + NS1 + NS2), and a second one in non-structural region. Dimensions of recombination sites can vary from 86 to 1072 nucleotide bases. The study identified "hot spots" of recombination in the strains of genotype 6 of hepatitis C virus. The recombinants were found in the population of the three countries: the United States (from the serum of an immigrant), Hong Kong and China

The groups of patients by genetic research for sensibility to Dalcetrapib therapy

The article deals with the search for phenotypic differences between patients with genotypically determined susceptibility to the drug Dalcetrapib and without it.В статье рассмотрены вопросы поиска фенотипических отличий между пациентами с генотипически обусловленной восприимчивостью к препарату Далцетрапиб и без нее

CHARACTERISTICS OF THE BAIKAL SUBTYPE OF TICK-BORNE ENCEPHALITIS VIRUS CIRCULATING IN EASTERN SIBERIA

Background. During the study of the genetic variability of the tick-borne encephalitis virus (TBEV) in Eastern Siberia, a group of 22  strains with a unique genetic structure significantly different from all  known TBEV subtypes was identified. This TBEV variant was  tentatively called “group 886”. Therefore, for this original TBEV  variant it was necessary to study the genetic, biological properties of the “group 886” strains, clarify its TBEV taxonomic status, its range, evolutionary history, etc.Aim. The generalization of the currently available data on genetic and biological properties of TBEV “886” group.Materials and methods. The genetic structure of “group 886” strains was studied by the complex of molecular-genetic methods (MHNA, sequencing of fragments or the complete genome).Results. It was shown that “group 886” strains form a separate cluster on phylogenetic tree, and the level of genetic differences  from other genotypes is more than 12 %. It was defined that this  TBEV variant has its own area (Irkutsk region, Republic of Buryatia,  Trans-Baikal region, Northern Mongolia). Its ecological connection  with all links of the transmissive chain (ixodid ticks, small mammals,  human), participation in human pathology, stability and duration of  circulation in the Baikal region, individual evolutionary history  were proved. Some phenotypic characteristics of the “group 886” strains were considered.Conclusion. The presented data testify to the validity of the “886 group” isolation as an independent genetic type. Taking into account  the geographical distribution of this TBEV genotype, we propose to assign it the name “Baikal genotype/subtype”

The groups of patients by genetic research for sensibility to Dalcetrapib therapy

This review article defines several aspects of phenotypic variations of patients with increased sensitivity to Dalcetrapib therapy and people who doesn't have any genetically-based predisposition to it.В статье рассмотрены вопросы определения фенотипических отличий пациентов с повышенной восприимчивостью к препарату Далцетрапиб и людей, не имеющих генотипическую предрасположенность к данному препарату

Characteristics of genetic and phenotypic properties of tick-borne encephalitis virus strains isolated from various source on the territory of Eastern Siberia

Since ixodid ticks and their feeders (vertebrates) form the basis of the tick-borne encephalitis virus (TBEV) population, it was interesting to obtain a genetic characteristic of strains isolated from various sources in the territory of Eastern Siberia. In our study, it was found that the circulation of TBEV of genotypes 1, 2, 3, 5 and "polytypic" strains in the territory of Eastern Siberia is maintained both by the main vectors (I. persulcatus ticks) and by their feeders (small and large mammals, birds). The distribution of genotypes in strains groups from ixodid ticks and vertebrates varied. TBEV strains of genotypes 1 and 2 were significantly more often isolated from rodents, and genotype 3 from ixodid ticks (p < 0.05). Isolates of genotype 3 (85.5 %) prevailed in the group of strains isolated from ixodid ticks, of which 29.6 % belonged to "Vasilchenko", and 25.6 % to "Zausaev"subgenotypes. Genotypes 1 and 2 were represented by single isolates (3.3 % and 1.3 %, respectively). Among strains isolated from warm-blooded hosts, the proportion of genotype 1 was 35.3 %, genotype 2 -11.8 %, genotype 3 - 35.3 %. More than half of genotype 3 strains (58.3 %) were related to "Vasilchenko" subgenotype, and the strains of "Zausaev" subgenotype were not detected. The obtained data suggest that ixodid ticks and warm-blooded animals are amplifiers of TBEV of genotypes 3 and 1, respectively. The certain differences in the phenotypic characteristics of strains isolated from ticks and warm-blooded animals have been revealed. It has been found that strains isolated from ticks are more homogeneous in their antigenic characteristics, less heterogeneous in S-feature than strains isolated from warm-blooded sources. The strains isolated from warm-blooded animals demonstrate somewhat greater resistance to warming but reducing the reproduction of the virus at 42 °C, and have greater virulence compared to strains isolated from ticks

The distribution of tick-borne encephalitis virus genotypes in different types of landscapes of Eastern Siberia

To find out what is the role of some environmental factors in the formation of a heterogeneous viral population, the analysis of the distribution of tick-borne encephalitis virus (TBEV) genotypes in different types of landscapes of Eastern Siberia has been carried out. In our study, it was shown that TBEV area in all investigated landscapes of Eastern Siberia is represented not only by TBEV of genotype 3, absolute dominance of which is noted in the studied regions, regardless the landscapes where the foci are located, but also by strains of other genotypes. The relationship between genotypes 1,3 and "polytypic" strains with a certain type of landscape and the degree of their development by man has not been established. The prevailing number of strains of TBEV genotype 5 is isolated from the material collected in the Transbaikalia, in the landscapes of the mountain taiga. They, as well as the strain of genotype 4, are found in the foci, where joint circulation of several TBEV genotypes is noted. The strains of TBEV genotype 2 were revealed in the landscapes of plains and plateaus taiga and insular steppes and forest steppes of the southern part of the Baikal region. Moreover, the detection of RNA of TBEV genotype 2 in the "polytipic" 763-87 and 765-87 strains isolated in the floodplain and forest-steppe landscapes of the Barguzin hollow does not exclude the possibility of circulation of TBEV genotype 2 in the Transbaikalian foci. The greatest genetic heterogeneity of TBEV is observed in natural foci located along Lake Baikal and in the southeastern part of Transbaikalia

APPLICATION OF MATHEMATICAL METHOD PREDICTIONS FOR IDENTIFICATION OF PATTERNS RELATIONS MUTATIONS IN PROTEINS ENCEPHALITIS VIRUS AND A MANIFESTATION OF ITS PHENOTYPIC TRAITS

We studied the natural connections between the amino acid sequences of proteins C, prM, E and NS1 virus strains of tick-borne encephalitis (TBE) and their three phenotypic traits -neuroinvasiveness, thermal stability and thermoresistance. Coupling strength is assessed using measures of competitive sequence similarity of each strain with reference strains. For such purposes subsets of strain sections are chosen amino acid composition specifics of which can predict the value of a phenotypic trait of interest. The possibility to predict missing elements in data both in amino acid composition, and in target properties is demonstrated. The relationships between pairs of phenotypic traits of strains were evaluated

SPECIES AND GENETIC VARIETY OF TICK INFECTIONS PATHOGENS ON THE TERRITORY OF THE EASTERN SIBERIA

The article sums up long-term, researches of studying of species and genetic variety of tick infections pathogens in combined, natural focuses of the Eastern Siberia. The results of the research testify to the high genetic variety of regional population, of tick-borne encephalitis virus that is represented, by the strains of Far-Eastern, West, Ural-Siberian genotypes, the strains of the group 886 and. 178-79. Infection of Ixodidae by the next pathogens: B. garinii, B. afzelii, R. sibirica, R. raoultii (генотипы. R. sp. DnS14, R. sp. DnS28), E. muris, A. phagocytophilum и Candidatus «Neoehrlichia mikurensis» was determined