In the study, the characteristics of the phase transition from a face-centered cubic crystal to a homogeneous phase in helium were calculated based on the correlation cell–cluster extension. A ...comparison of theoretical data with experimental data was conducted, and good agreement was obtained. The use of data on phase transitions in helium for estimating the thermodynamic characteristics of the phase transition in a quantum system of hard spheres is discussed.
Introduction
Oral health behavior is based on an acquired experience and cultural traditions. University education may smooth out cultural differences in oral health practice.
Objectives
Our goal is ...to study self-reported oral health attitudes and behavior of university students and the cultural basis for it.
Methods
We used the English version of the Hiroshima University Dental Behavioral Inventory to carry out an online survey of 136 university students of Morocco and Russia.
Results
Over half of the students (60.3%) do not feel anxious when visiting a dentist. Most of them take care of their gums (41.2%), teeth color (49.3%) and the degree of their cleanness (38.2%). The overwhelming majority of the students brush their each tooth very thoroughly (62.5%), they regularly examine their teeth in the mirror after brushing them (90.4%). They are well aware that tooth brushing alone cannot prevent a gum disease (63.2%), and they feel concerned about the possibility of having bad breath (73.6%). At the same time, over half of the students (61.7%) put off their visit to a dentist until they have a toothache, which is a negative behavioral factor. We did not reveal any gender or cultural differences between the students of the two countries, which can be regarded as a universalization factor of oral health behavior in young people who get higher education in universities.
Conclusions
The majority of the surveyed Russian and Moroccan university students have similar patterns of oral health attitudes and behavior. This assumption needs verification on a larger sample of students.
Disclosure
No significant relationships.
In the present work, for the first time, a generalized Guggenheim equation for a system of hard spheres has been obtained based on the use of Euler’s accelerated convergence method. This equation ...allows for the consideration of an arbitrary number of known virial coefficients. For the metastable region, this equation is generalized to account for the asymptotic behaviour of free energy at high densities. The obtained expression for the compressibility of the homogeneous phase of a hard sphere system describes the data of the numerical experiment within the limits of its accuracy.
genus of Asteraceae family is a source of medicinal plants known worldwide and used as ethnopharmacological remedies for the treatment of diabetes in Northern Asia (Siberia). The aim of this study ...was to determine the phenolic profile of 12 Siberian
species (
) and to test the efficacy of plant extracts and pure compounds for antidiabetic potential. Finally, by HPLC-DAD-ESI-TQ-MS/MS technique, 112 individual phenolic compounds were detected in
extracts in a wide range of concentrations. Some species accumulated rare plant phenolics, such as coumarin-hemiterpene ethers (lacarol derivatives) from
and
; melilotoside from
; dihydrochalcones (davidigenin analogs) from
; chrysoeriol glucosides from
, and
; eriodictyol glycosides from
; and some uncommon flavones and flavonols. The predominant phenolic group from
species herb was caffeoylquinic acid (CQAs), and in all species, the major CQAs were 5-
-CQA (20.28-127.99 μg/g) and 3,5-di-
-CQA (7.35-243.61 μg/g). In a series of
bioassays, all studied
extracts showed inhibitory activity against principal enzymes of carbohydrate metabolism, such as α-amylase (IC
= 150.24-384.14 μg/mL) and α-glucosidase (IC
= 214.42-754.12 μg/mL). Although many phenolic compounds can be inhibitors, experimental evidence suggests that the CQAs were key to the biological response of
extracts. Mono-, di- and tri-substituted CQAs were assayed and showed inhibition of α-amylase and α-glucosidase, with IC
values of 40.57-172.47 μM and 61.08-1240.35 μM, respectively, and they were more effective than acarbose, a well-known enzyme inhibitor. The results obtained in this study reveal that Siberian
species and CQAs possess a pronounced inhibitory activity against α-amylase and α-glucosidase and could become a complement to synthetic antidiabetic drugs for controlling blood glucose level.
NMDA receptors play critical roles in numerous physiological and pathological processes in CNS that requires development of modulating ligands. In particular, photoswitchable compounds that ...selectively target NMDA receptors would be particularly useful for analysis of receptor contributions to various processes. Recently, we identified a light-dependent anti-NMDA activity of the azobenzene-containing quaternary ammonium compounds DENAQ (diethylamine-azobenzene-quaternary ammonium) and DMNAQ (dimethylamine-azobenzene-quaternary ammonium). Here, we developed a series of light-sensitive compounds based on the DENAQ structure, and studied their action on glutamate receptors in rat brain neurons using patch-clamp method. We found that the activities of the compounds and the influence of illumination strongly depended on the structural details, as even minor structural modifications greatly altered the activity and sensitivity to illumination. The compound PyrAQ (pyrrolidine-azobenzene-quaternary ammonium) was the most active and produced fast and fully reversible inhibition of NMDA receptors. The IC50 values under ambient and monochromic light conditions were 2 and 14 μM, respectively. The anti-AMPA activity was much weaker. The action of PyrAQ did not depend on NMDA receptor activity, agonist concentration, or membrane voltage, making it a useful tool for photopharmacological studies.
The article describes a method for producing semi-finished products from a copper alloy of the Cu–Ni–Cr–Si system for electrical purposes through the radial-shear rolling (RSR). From the Cu–Ni–Cr–Si ...alloy by hot deformation, rods with a diameter of 20 mm were obtained, which were then heat treated with quenching and aging. A detailed analysis of the microstructure and properties (mechanical and electrical) of the obtained samples was carried out after RSR and after heat treatment (HT). After RSR, material hardening occurs due to shear deformations forming a gradient structure with grain sizes varying from 8.22 μm to 15.95 μm between the surface and the center of the rod. The microstructure and mechanical property analysis showed that after heat treatment, the alloy is thermally hardened due to the precipitation of Ni2Si and Cr3Si particles uniformly distributed in the sample volume in the form of fine inclusions with an average size of 0.56–0.65 μm. After heat treatment, the alloy enhanced its mechanical properties (ultimate tensile strength (UTS) ~ 700–750 MPa, yield strength (YS) ~ 557–606 MPa, and elongation between 17 and 22%) and its electrical conductivity of 45.17% IACS from the 30.52% IACS of the RSR material. The improved mechanical properties of the heat-treated material are due to the different strength contributions mainly coming from dislocations and precipitates. The electrical conductivity improvement after the heat treatment is related to the dislocation density reduction and the increase in grain boundary misorientation due to the recrystallization phenomenon giving rise to a lower number of boundaries but with a twinning character. Thus, the RSR method offers a new industrial alternative for the production of semi-finished products from a Cu–Ni–Cr–Si alloy in the form of rods with diameters ranging from 10 to 55 mm.
•Radial shear rolling can produce copper rods of different diameters at an industrial scale.•The thermomechanical process using radial shear rolling gives rise to a heterogeneous material.•Aging treatment after radial shear rolling produces a remarkable combination of strength, ductility, and electrical conductivity.•Dislocations annihilation and grain boundaries misorientation change help to improve the material electrical conductivity.
Current status of tokamak T-15MD Khvostenko, P.P.; Anashkin, I.O.; Bondarchuk, E.N. ...
Fusion engineering and design,
March 2021, 2021-03-00, 20210301, Letnik:
164
Journal Article
Recenzirano
•T-15MD project is aimed at obtaining a database for creating a thermonuclear neutron source for atomic energy needs.•Magnet system of T-15MD will confine the hot plasma in the divertor ...configuration.•Toroidal magnetic field at the plasma axis is 2 T, plasma current is 2 MA.•Preparation to physical start-up of tokamak T-15MD is completed.•T-15MD should begin operation in 2021.
At the present time, the preparation to physical start-up of tokamak T-15MD is completed in the National Research Center “Kurchatov Institute”. The main parameters of T-15MD are: R = 1.48 m, a = 0.67 m, B = 2.0 T, Ipl = 2.0 MA. The magnet system is capable to maintain without overheating (more 60 °C) the plasma current of 2 MA for 4 s, 1 MA for 20 s, 700 kA for 40 s, 500 kA for 80 s, 300 kA for 160 s and 250 kA for 400 s. Plasma current drive can be maintained either by injection of fast neutrals or by electron cyclotron (EC)-, ion cyclotron (IC)- and low hybrid (LH) - waves. In August 2019 the electromagnetic system, consisting of TF and PF coils, together with vacuum vessel have been assembled in experimental hall. Power supply system of Tokamak T-15MD includes: two substations 110/10 kV, two substations 10/0.83 kV, thyristor convertors and different equipment. Total power consumption during the pulse with plasma current 2 MA and additional plasma heating of 20 MW will consist of 300 MVA. Power supply system is in the commissioning. Tokamak T-15MD will be operate using the information and control system. All the information and control system equipment, required for the implementation of physical start-up of tokamak T-15MD, is available. For plasma control the 250 different electromagnetic probes are installed inside vacuum vessel. The gyrotron with frequency 82.6 GHz and power of 1 MW will be used for pre-ionization.
A
bstract
In this paper we study the interactions among a static quark-antiquark pair in the presence of dense two-color quark matter with lattice simulation. To this end we compute Polyakov line ...correlation functions and determine the renormalized color averaged, color singlet and color triplet grand potentials. The color singlet grand potential allows us to elucidate the number of quarks induced by a static quark antiquark source, as well as the internal energy of such a pair in dense quark matter. We furthermore determine the screening length, which in the confinement phase is synonymous with the string breaking distance. The screening length is a decreasing function of baryon density, due to the possibility to break the interquark string via a scalar diquark condensate at high density. We also study the large distance properties of the color singlet grand potential i a dense medium and find that it is well described by a simple Debye screening formula, parameterized by a Debye mass and an effective coupling constant. The latter is of order of unity, i.e. even at large density two-color quark matter is a strongly correlated system.
We examine how country-level institutional context moderates the relationship between three socio-cognitive traits—entrepreneurial self-efficacy, alertness to new business opportunities, and fear of ...failure—and opportunity entrepreneurship. To do this, we blend social cognitive theory (SCT) with institutional theory to develop a multi-level model of entrepreneurial entry. We merge data from the Global Entrepreneurship Monitor (GEM) surveys and the Economic Freedom of the World (EFW) index for 45 countries from 2002 to 2012. Our results, which are based on a multi-level fixed-effects model, suggest that entrepreneurs' self-efficacy and alertness to new opportunities promote opportunity entrepreneurship while fear of failure discourages it. However, the strength of these relationships depends on the institutional context, with entrepreneurial self-efficacy and alertness substantially more likely to lead to new opportunity-driven ventures in countries with higher levels of economic freedom. These results provide suggestive evidence that economic freedom not only channels individual effort to productive entrepreneurial activities, but also affects the extent to which individuals' socio-cognitive resources are likely to mobilized and lead to high-growth entrepreneurship.
•We blend social cognitive theory (SCT) with institutional theory to develop a multi-level model of entrepreneurial entry.•Entrepreneurial self-efficacy and alertness promote opportunity entrepreneurship while fear of failure discourages it.•The strength of these relationships depends on the institutional context.•Entrepreneurial self-efficacy and alertness promote opportunity entrepreneurship in countries with more economic freedom.•Individuals who are not afraid of failure are more involved in opportunity entrepreneurship when economic freedom is high.
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