Aim
During early post‐natal development, arterial contraction depends less on Ca2+‐signalling pathways but more on changes in Ca2+‐sensitivity compared to adult animals. Whether this difference is ...related to Rho‐kinase, one of the major players affecting Ca2+‐sensitivity, is unknown for intact vessels. Thus, we tested the hypothesis that Rho‐kinase critically contributes to the higher Ca2+‐sensitivity of contraction in intact arteries of 1‐week‐old rats.
Methods
We studied 1‐week‐old, 4‐ to 5‐week‐old and 10‐ to 12‐week‐old rats performing isometric myography, Ca2+‐fluorimetry and Western blotting using intact saphenous arteries and arterial pressure measurements under urethane anaesthesia.
Results
In 10‐ to 12‐week‐old rats, methoxamine (MX) produced vasoconstriction associated with an increase in Ca2+i and Ca2+‐sensitivity. In contrast, in 1‐week‐old rats these contractions were accompanied only by an increase in Ca2+‐sensitivity. All MX‐induced effects were reduced by the Rho‐kinase inhibitor Y‐27632; this reduction was complete only in 1‐week‐old rats. The Rho‐kinase specific site Thr855 on MYPT1 was increasingly phosphorylated by MX in vessels of 1‐week‐old, but not 10‐ to 12‐week‐old rats; this effect was also inhibited completely by Y‐27632. The Rho‐kinase inhibitor fasudil in a dose not affecting the pressor response to MX in 4‐ to 5‐week‐old rats reduced it considerably in 1‐week‐old rats.
Conclusion
Our results suggest that the higher Ca2+‐sensitivity of arterial contraction in 1‐week‐old compared to 10‐ to 12‐week‐old rats is due to a greater Rho‐kinase activity. Constitutively active Rho‐kinase contributes to MX‐induced contraction in 10‐ to 12‐week‐old rats. In 1‐week‐old rats, additional Rho‐kinase activation is involved. This remodelling of the Rho‐kinase pathway is associated with its increased contribution to adrenergic arterial pressure responses.
Conditions of the synthesis of nanoparticles of ractopamine molecularly imprinted polymers (
MIP
) by the precipitation method are studied. It is shown that the size and dispersity of MIP particles ...are largely determined by the nature of the functional and cross-monomers and by the synthesis conditions: temperature, mixing rate, duration of synthesis, and ultrasonic treatment of the polymerization mixture before and after the synthesis. It is found that ractopamine MIP particles based on methacrylic acid and ethylene glycol dimethacrylate, sonicated for 30 min, have a minimum size and degree of dispersion. Using the piezoelectric quartz micro-weighing method, characteristics of the recognition layer based on MIP nanoparticles are found, and the analytical characteristics of a sensor for the determination of ractopamine in an aqueous solution are calculated.
The article discusses the issues of assessing sustainability of economic development of enterprises in the context of increasingly competitive environment and a variety of external factors of ...influence. The aim of the study is to develop a comprehensive approach to assessing long-term sustainability of economic development of enterprises in conditions of uncertainty of the external environment. It is emphasized that it is crucial to develop an integrated approach to the problem of sustainability that combines assessments of the following: the resource base of production; performance indicators; and efficiency of realization of economic potential, as well as the overall balance of economic growth. An enterprise’s adaptability to its external environment, its ability to quickly and adequately respond to changes in that environment and counteract any negative effects – all of that is encompassed by the concept of economic sustainability. The results of the study are proposed for use in further assessments of sustainability of economic development of enterprises in various industries.
Two series of steel samples with a copper content of 0–9 wt.% were obtained. The first series is a hypereutectoid steel with varying copper content. The structure of the samples of the second series ...contains graphite formed as a result of modification inside the mold with 0.15 wt.% of silicocalcium. The paper shows the change in the form of graphite with an increase in the copper content in steel. Particular attention was paid to the structure of the particles of the ε-Cu phase. The study presents a scheme for the formation of a structure inside large particles of the ε-Cu phase. By reducing the solubility of iron in copper inside the ε-Cu phase during crystallization and cooling of the particles of the ε-Cu phase, the formation of three types of particles based on iron is anticipated. The results of the influence of copper on the following mechanical properties are shown: hardness, ultimate strength under uniaxial static tension and compression.
Predictive diagnostics in industry and in railroad transportation on the basis of the Industrial Internet of Things is analyzed. Attention focuses on predictive diagnostics in the maintenance and ...repair of locomotives and motorized rail cars and prospects for a differential approach to operational support. Empirical methods are employed: (1) comparison, so as to identify the similarities and differences of predictive diagnostic systems of the same type used for the maintenance and repair of locomotives and motorized rail cars in the depot; (2) description: itemization of the available data regarding predictive diagnostic systems for the maintenance and repair of locomotives and motorized rail cars. A positional map is prepared, showing existing predictive diagnostic systems in terms of the manufacturers’ characteristics and the type of locomotive or motorized rail car. On the basis of the chart, a differential approach to the introduction of predictive diagnostic systems for specific companies is adopted. Predictive diagnostic systems are compared in terms of eight parameters used in maintenance and repair of locomotives and motorized rail cars in the depot. The advantages and disadvantages of each system are noted; a ranking is prepared. The analysis leads to the conclusion that the inefficient existing maintenance system based on standard preventive measures must be replaced by a predictive system.
During early post-natal development, arterial contraction depends less on Ca
-signalling pathways but more on changes in Ca
-sensitivity compared to adult animals. Whether this difference is related ...to Rho-kinase, one of the major players affecting Ca
-sensitivity, is unknown for intact vessels. Thus, we tested the hypothesis that Rho-kinase critically contributes to the higher Ca
-sensitivity of contraction in intact arteries of 1-week-old rats.
We studied 1-week-old, 4- to 5-week-old and 10- to 12-week-old rats performing isometric myography, Ca
-fluorimetry and Western blotting using intact saphenous arteries and arterial pressure measurements under urethane anaesthesia.
In 10- to 12-week-old rats, methoxamine (MX) produced vasoconstriction associated with an increase in Ca
and Ca
-sensitivity. In contrast, in 1-week-old rats these contractions were accompanied only by an increase in Ca
-sensitivity. All MX-induced effects were reduced by the Rho-kinase inhibitor Y-27632; this reduction was complete only in 1-week-old rats. The Rho-kinase specific site Thr
on MYPT1 was increasingly phosphorylated by MX in vessels of 1-week-old, but not 10- to 12-week-old rats; this effect was also inhibited completely by Y-27632. The Rho-kinase inhibitor fasudil in a dose not affecting the pressor response to MX in 4- to 5-week-old rats reduced it considerably in 1-week-old rats.
Our results suggest that the higher Ca
-sensitivity of arterial contraction in 1-week-old compared to 10- to 12-week-old rats is due to a greater Rho-kinase activity. Constitutively active Rho-kinase contributes to MX-induced contraction in 10- to 12-week-old rats. In 1-week-old rats, additional Rho-kinase activation is involved. This remodelling of the Rho-kinase pathway is associated with its increased contribution to adrenergic arterial pressure responses.
The article is devoted to a possible commutation resource as a phenomenon of substitute commutation in supporting education by the model of "mother hearing-impaired student with a complex defect ...structure, which includes autism spectrum disorder"; the commutation reserves are considered to understand family support technologies. On the one hand, the communication technologies manifesting the new digital communication era may be demanded by today's disabled young people as alternative tools for virtualization of modern life. On the other, the modern digital environment supports the concept of accessibility and equal opportunities for building individual education paths at the stages of both secondary and accessible professional education.
Theoretical analysis of the degradation of the current–voltage characteristic and transient ionization processes occurring in a low-barrier uncooled GaAs Mott diode under the action of heavy ions ...from outer space and laser pulses simulating them is carried out. The response of the diode to the action of an arsenic ion with an energy of 200 MeV, which corresponds to a linear energy transfer of 26 MeV cm
2
/mg, is compared with the response to the action of femtosecond optical-radiation pulses with a duration of 10 fs at wavelengths of 870 and 670 nm.
•An implicit computational algorithm for modified Navier–Stokes equations to simulate flows in anisotropic porous media.•A general coupled block matrix is solved with the algebraic multigrid ...solver.•The proposed algorithm is verified in comparison with the SIMPLE algorithm on a series of benchmark problems.•The total problem runtimes and number of iterations required for complete convergence are given.
A coupled computational algorithm for modified Navier–Stokes equations to simulate flows in anisotropic porous media is proposed and described. The difference from the classic SIMPLE algorithm is in the completely implicit relationship between velocity and pressure owing to the implicit terms of the pressure and mass flow gradients in the continuity equation and momentum equation. One of the attractive features of this algorithm is the possibility of completely implicit discretization of off-diagonal components of the porous medium resistance tensor in the right-hand side of the momentum equation. Implicit discretization allows reducing the number of linear iterations as compared to the SIMPLE algorithm with explicit discretization of off-diagonal components. The specific features of discretization of modified equations including the discretization of boundary conditions and components of the porous medium resistance tensor are considered. The proposed algorithm is verified in comparison with the SIMPLE algorithm on a series of benchmark problems, such as the problem of a flow through a porous insert, a flow in a divided channel, and a flow through a cylindrical porous filter. The total problem runtimes and the number of iterations required for complete convergence are given to compare the two algorithms.
•Pre-oxidized titanium hydride powder is a suitable blowing agent for aluminum foams.•The optimal mode of powder oxidation by air oxygen is warming up at ∼440°С for 1h.•The external pressure is the ...influential factor affecting the foaming process.
One of the well-known ways of metal foam production consists of adding powder which releases gaseous decomposition product at high temperatures into a melted metal. When producing aluminum foams, titanium hydride powder is most frequently used, while its main disadvantage is its insufficient thermal stability. This results in a premature gas loss in the process of the powder introduction into a melted metal matrix. The paper discloses approaches to suppression of the undesirable premature titanium hydride decomposition by means of its preliminary thermal treatment, as well as the external pressure elevation over that of the system being processed during the foam formation. A method of using the thermally treated powder is proposed, in order to obtain aluminum foam samples having a required geometry and sufficiently uniform porous structure.
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