η -nuclei in the SCAN experiment Michaličková, Katarína; Afanasiev, S.V.; Dryablov, D.K. ...
EPJ Web of Conferences,
2019, Letnik:
204
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
η
-mesic nucleus or the quasibound nuclear state of an
η
-meson in a nucleus is caused by the strong-interaction force alone. The project SCAN2 is aimed at searching and studying the
η
-meson nuclei ...production. The experiment is based on two-arms spectrometer using internal target at the Nuclotron. The setup was designed to study products from
η
-meson nucleus decay in the reaction
d
+
12
C → (A)
η
+
X
→
π
+
p
+ (
A –
2) at deuteron energies from 0:5 to 2:5 GeV/nucl. The energy spectrum of secondary protons has been measured. The dependence of the yields of protons and pions on the beam energy has been obtained. This dependence can show us the minimum energy for the
S
11
resonance formation. The first prototype of the neutron detector, which will be used in a new modified experimental setup SCAN3 for recording of neutrons from
η
-nucleus decays in the
πn
and
pn
channels, has been tested. The time-offlight method to obtain the neutron spectrum was used. The time resolution and efficiency of the neutron detector have been obtained.
In the present work, we studied the catalytic performance of an oil-soluble nickel-based catalyst during aquathermolysis of oil-saturated crushed cores from Boca de Jaruco extra-heavy oil field. The ...decomposition of nickel tallate and some aspects of in-situ transformation of the given catalyst precursor under the steam injection conditions were investigated in a high-pressure batch reactor using XRD and SEM analysis methods. The changes in physical and chemical properties of core extracts after the catalytic aquathermolysis process with various duration were studied using gas chromatography for analyzing gas products, SARA analysis, GC-MS of saturated and aromatic fractions, FT-IR spectrometer, elemental analysis, and matrix-activated laser desorption/ionization (MALDI). The results showed that nickel tallate in the presence of oil-saturated crushed core under the injection of steam at 300 °C transforms mainly into nonstoichiometric forms of nickel sulfide. According to the SEM images, the size of nickel sulfide particles was in the range of 80–100 nm. The behavior of main catalytic aquathermolysis gas products such as CH4, CO2, H2S, and H2 depending on the duration of the process was analyzed. The catalytic upgrading at 300 °C provided decrease in the content of resins and asphaltenes, and increase in saturated hydrocarbon content. Moreover, the content of low-molecular alkanes, which were not detected before the catalytic aquathermolysis process, dramatically increased in saturates fraction after catalytic aquathermolysis reactions. In addition, the aromatics hydrocarbons saturated with high molecular weight polycyclic aromatic compounds—isomers of benzo(a)fluorine, which were initially concentrated in resins and asphaltenes. Nickel sulfide showed a good performance in desulfurization of high-molecular components of extra-heavy oil. The cracking of the weak C–S bonds, which mainly concentrated in resins and asphaltenes, ring-opening reactions, detachment of alkyl substitutes from asphaltenes and inhibition of polymerization reactions in the presence of catalytic complex reduced the average molecular mass of resins (from 871.7 to 523.3 a.m.u.) and asphaltenes (from 1572.7 to 1072.3 a.m.u.). Thus, nickel tallate is a promising catalyst to promote the in-situ upgrading of extra-heavy oil during steam injection techniques.
—
The features of the functional state of the rat myocardium and the activity of the lipid peroxidation processes were studied under the conditions of concomitant development of heart failure of ...ischemic etiology and diabetes mellitus. The rhythmoinotropic myocardial reaction and the content of active products of thiobarbituric acid and diene conjugates in the blood plasma of rats with postinfarction and diabetic heart remodeling were assessed separately and under their combined development. Under experimental conditions with the development of post-infarction cardiac remodeling, it was shown that the induction of diabetes leads to suppression of the increase in the activity of lipid peroxidation and maintenance of myocardial rhythmoinotropic reactions.
We compared the capability of human fibroblasts to populate porous polycaprolactone (PCL) scaffolds modified during fabrication with surface-active agents Triton Х-100 (type 1 scaffold) and ...polyvinylpyrrolidone (type 2 scaffold). The mean fiber diameter in both scaffolds was almost the same: 3.90±2.19 and 2.46±2.15 μ, respectively. Type 1 scaffold had higher surface density and hydrophilicity, when type 2 scaffold was 1.6 times thicker. The cells were seeded on the scaffolds by the dynamic seeding technique and then cultured in Petri dishes with nutrient medium in a humid atmosphere. During 3-day culturing, no cell release from the matrix was noted. DAPI staining proved the presence of cells in both scaffolds. However, in type 1 scaffold the cells populated the whole thickness, while in type 2 scaffold, the cells were present only in the superficial layer. These findings suggest that PCL scaffolds modified with Triton Х-100 or polyvinylpyrrolidone are not cytotoxic, but the structure of the scaffold treated with Triton Х-100 is more favorable for population with cells.
In this work, the membrane structures based on lead-free ferroelectric barium strontium titanate with composition Ba
0.8
Sr
0.2
TO
3
(BSTO) were fabricated by a magnetron sputtering method. The ...formation of a single-phase Ba
0.8
Sr
0.2
TO
3
with thickness of 300 nm sintered on Si substrate is confirmed by XRD analysis. It is shown that films without a silicon substrate exhibit ferroelectric and piezoelectric properties. The piezoelectric and ferroelectric behaviors of BSTO thin film without a silicon substrate were confirmed through a piezoelectric force microscopy and Kelvin probe force microscopy and measurements of the effective piezoelectric coefficients (
d
33
and
d
15
). Images of the residual potential of polarized areas have been obtained on the membranes, which are stable over time despite the absence of a lower electrode. Additionally, a local of ferroelectric hysteresis loop has been observed. A combination of the structural and piezoelectric measurements reveals that it possible to create freestanding ferroelectric films based on Ba
0.8
Sr
0.2
TO
3
system, establishing it as a promising candidate for high-performance electromechanical applications.
Purpose: whooping cough diagnostics by molecular-genetic methods.Materials and methods. Under observation there were 4930 people during the period from 2012 to 2015. All samples were received in 8 ...schools of Moscow and the Moscow region: in 3 schools had been found children with whooping cough, in other 5 schools – only children with prolonged cough. Whooping cough diagnosis had been given earlier by bacteriological and serological methods. 430 clinical samples were studied by 2 methods: PCR with fluorescent hybridized detection of amplified products and isothermal amplification.Results. In three of eight schools whooping cough cases at 7 children at the age of 7, 9, 11 and 15 years were revealed earlier. The diagnosis of whooping cough at them was confirmed by means of bacteriological and serological methods. 33 positive DNA samples (7.7%) are revealed. DNA-positive samples are allocated from 18 pupils and 15 employees of schools. In two schools where earlier infection sources were established, 15 DNA-positive samples from which in three cases clinical manifestations were observed are revealed. In those schools where it wasn’t earlier established a source of an infection and examinations conducted it is long the coughing children, 18 DNA-positive samples are revealed, and in two cases clinical manifestations in the form of cough were observed.Conclusion. Performed research confirmed high efectiveness of molecular-genetic methods during pertussis infection foci examination in schools for infection source identification also amongst long coughing children.
The aim of the study was to characterize toxigenic strains of Corynebacterium diphtheriae by examining 12 toxigenic strains of C. diphtheriae isolated in Russia between January, 2017 to June, 2019. ...The morphological, toxigenic and biochemical properties of C. diphtheriae was studied. Genotyping of C. diphtheriae strains was performed using MLST and dtxR gene sequencing with subsequent phylogenetic analysis. Results. Toxigenic strains of C. diphtheriae were isolated in the Novosibirsk, Samara and Chelyabinsk Regions, the Khanty-Mansi Autonomous Okrug — Yugra as well as the Republic of Northern Ossetia — Alania. Among these strains, 5 were isolated from diphtheria patients (moderate disease found in one case, mild course — remaining patients) and 7 strains were isolated from bacterial carriers. In two cases C. diphtheriae from diphtheria patients were identified as ST25 sequence type, gravis variant; in one case — ST8 type, gravis variant; two cases — ST67 sequence type, mitis variant. In asymptomatic carriers of tox-positive C. diphtheriae strains they belonged to ST25 sequence type, gravis variant — in two cases, ST67 type, mitis variant — in four cases. A sequencing type was not identified in one case. All sequence types were widespread globally being presented by a large number of isolates in the PubMLST and characterized by a substantial amount of derivative sequence types. At the same time, they belonged to different clonal complexes and differed markedly from each other contributing to their reliable difference as assessed by MLST. Study of gene dtxR sequence diversity showed that all allelic variants were typical for the representatives of these sequence types. New alleles of gene dtxR were not revealed in strains examined. It was shown that non-synonymous substitution C440T leading to A147V amino acid substitution was found solely in one allele distributed in ST8, ST185, ST195 and ST451 types suggesting at late mutation. In contrast, the polymorphism C640A resulting in the amino acid substitution L214I was found not only in the same allele, but also in the basal tree branches indicating that isoleucine was in the ancestral sequence of the protein.
Possibilities of using eukaryotic microorganisms (Candida spp.) of microbiocenoses of mucosal open cavities as potential biomarkers of pathological states of biotopes were investigated. To identify ...biotopes characterizing Candida strains we used new promising natural glycoconjugate recognition agents -lectins that imitate the effect of probiotics. The lectins were isolated from cultures of probiotic strains of lactobacillus and bifidus bacteria characterizing and supporting probiotic compartment of microbiocenosis of human mucosal open cavities as part of endogen sensory system "lectins of probiotic microorganisms - opportunistic eukaryotic yeast-like fungi". The study was carried out on examples of cases of dysbiotic disorders in the composition of microbiocenoses against the background of pathologies of the urogenital tract of patients with established diagnosis. Results demonstrate the early (before development of visible inflammatory reactions) presence of changed Candida cells in pathological biotopes of urogenital tract indicating states of diseases characterizing with increased differentiating affinities and sensitivities of Candida to a panel of probiotic lectins. Probiotic lectins are perspective in combinative prognostics and diagnostics of pathological states of functional biotopes of human mucosal open cavities as well as for prophylaxis and therapy of such states by compensation of deficit or absence of probiotic microflora to support healthy balance of mucosal immunity, instead of probiotics or in combinations with probiotics, antibiotics and other antimicrobial agents, therapeutics, and factors. The data also perspective in study of pathological biotope states possessing risk of conversion into tumor-like landscapes.
PDF
