—
The production of reactive oxygen species (ROS) in skeletal muscle cells increases under contraction. Respiratory and locomotor muscles differ in contraction modes; therefore, ROS production and ...their effect on blood vessels in these functionally different types of muscles may differ. The aim of this work was to assess the role of ROS in the tone regulation of the diaphragm artery (
a. phrenica
) and deep brachial artery (
a. profunda brachii
) of the rat. The reactions of ring preparations of the arteries were studied in the isometric regimen. The NADPH oxidase (NOX) inhibitor VAS2870 caused relaxation of the preparations; the reaction magnitude of the diaphragm arteries was greater than that of the brachial arteries: at the VAS2870 concentration of 1 μM, the contraction force decreased to 33 and 91% of the precontraction level, respectively. Tiron (
scavenger) had a similar activity profile: at the concentration of 10 mM, it caused a decrease in the contraction force of the diaphragm arteries to 38% and of the brachial arteries to 66% of the initial contraction force. Catalase, which destroys H
2
O
2
, did not affect contraction of the diaphragm arteries at the concentration of 3000 U/mL but increased contraction of the deep brachial arteries. Using the method of quantitative polymerase chain reaction, it was shown that the mRNA content of
NOX
isoforms,
p22phox
,
p47phox
,
p67phox
,
Poldip2
,
Gpx-1
,
SOD-1
, and catalase in the tissue of two arteries does not differ, while the content of
SOD-3
mRNA in the diaphragm arteries is lower than in the brachial arteries. Thus,
produced by NOX greater increases tonic contraction of the diaphragm arteries than arteries of the locomotor muscle. H
2
O
2
, on the contrary, causes relaxation of the locomotor muscle arteries but not the diaphragm arteries. A relatively low level of
SOD-3
expression may be a reason for the pronounced effect of O
2–
in the diaphragm arteries.
Synthesis of glycidyl propargyl ether Tarasova, O. A.; Nedolya, N. A.; Trofimov, B. A.
Russian journal of organic chemistry,
11/2017, Letnik:
53, Številka:
11
Journal Article
Recenzirano
Glycidyl propargyl ether was prepared in 80% yield from propargyl alcohol and epichlorohydrin in a superbasic suspension NaOH–DMSO.
Applying B3LYP/6-31G(d,p) method we have performed a quantum-chemical study of structural transformations of propargyl and acetyl 2-methoxy-N-methylbuta-2,3-dienimidothioates (1-aza-1,3,4-trienes) ...into pyrroles and thiophenes. Heterocyclization mechanisms have been analyzed, thermodynamic and kinetic characteristics were obtained for the gradient channels of aza- and thiaheterocycles formation.
For the first time decomposition was investigated of 4-alkoxy-5-amino-3-methylthiophene-2-carbonitriles under the conditions of electronic (70 eV) and chemical (reagent gas methane) ionization. At ...the electronic ionization the compounds under study except for 4-(1-ethoxyethoxy) and 4-(ferrocenylmethoxy) derivatives form stable molecular ions that decompose mainly by the cleavage of an alkyl radical from the alkoxy-substituent. Further fragmentation of the arising ion
M
–Alk
+
depends on the substituent nature in the amino group. In the mass spectrum of 4-(ferrocenylmethoxy)-substituted thiophene peaks of the ion FcCH
2
+
and its fragmentation products prevail. In the mass spectra of chemical ionization predominant peaks belong to ions
M
+·
,
M
+
H
+
and
M
+ C
2
H
5
+
, and fragment ions are absent.
Derivatives of 2,3,6,7-tetrahydro-5
H
-1,3thiazolo3,2-
a
pyridine and 5,6-dihydropyridin-2(1
H
)-one were unexpectedly obtained at treating methyl ...2-(6-methyl-3-ethoxy-5,6-dihydropyridin-2-yl)sulfanyl-acetate with a dilute solution of hydrochloric acid. Their formation resulted from the hydration of 5,6-dihydropyridine at the C=N bond accompanied with the elimination of a methyl 2-sulfanylacetate molecule and the addition of the methyl 2-sulfanylacetate to the second 5,6-dihydropyridine molecule at the C
3
=C
4
bond followed by the elimination of a methanol molecule and the closure of a thiazole ring.
Age, gender, and typological features of the vegetative status, endocrine status, and nonspecific resistance were studied in older adolescents from a boarding school. Activity of the sympathetic ...regulation of vegetative functions was shown to decrease in the older adolescents; cortisol and testosterone increased in boys and decreased in girls during puberty. Parameters of the vegetative and hormonal regulation were associated with puberty specifics; i.e., more effective neuroendocrine relationships formed during the transition to puberty stage IV in boys and stage V in girls. Vagotonia was identified as the optimal type of autonomic regulation in later adolescence in boys, and a balanced initial autonomic tone, in girls. Adolescent boys with a vagotonic type of autonomic regulation differed from their peers with sympatheticotonic or eutonic types in having higher contents of cortisol and testosterone and a high level of nonspecific resistance; a characteristic feature of eutonic girls was a decrease in testosterone with an optimal functional state of the body. The results indicated that the parameters under study are of prognostic significance for assessing the adaptive capacity in adolescents during learning.
This review focuses on new aspects of endocannabinoid functions and mechanisms of activity in central and peripheral synapses, different from the general viewpoint that endocannabinoids are ...retrograde signaling molecules, which inhibit neurotransmitter release by activating specific presynaptic endocannabinoid receptors CB1 and CB2. Biased agonism of the endogenous and synthetic cannabinoids as well as ability of the CB-receptors to couple not only with classical G
i
-proteins, but also with G
s
- and G
q
-proteins and, moreover, with β-arrestins (thereby triggering additional signaling pathways in synapses) are described here in detail. Examples of noncanonical tonic activity of endocannabinoids and their receptors and their role in synaptic function are also presented. The role of endocannabinoids in short-term and long-term potentiation of neurotransmitter release in central synapses and their facilitating effect on quantal size and other parameters of acetylcholine release in mammalian neuromuscular junctions are highlighted in this review. In conclusion, it is stated that the endocannabinoid system has a wider range of various multidirectional modulating effects (both potentiating and inhibiting) on neurotransmitter release than initially recognized. Re-evaluation of the functions of endocannabinoid system with consideration of its noncanonical features will lead to better understanding of its role in the normal and pathological functioning of the nervous system and other systems of the body, which has an enormous practical value.
The approach to solving the applied problem of modernization of the 300 MW series power units produced by JSC "Ukrainian Energy Machines" by converting them from supercritical to ultra-supercritical ...steam parameters, provided that regenerative feed water heating system is preserved as much as possible, which will lead to an increase in the energy efficiency of the TPP with minimal conversion, is analyzed in the paper. The conversion of the K-300-240-2 power unit to the parameters of fresh steam 650 °C/30 MPa and intermediate superheated steam 650 °C/7 MPa, determined as optimal as a result of previous studies, can be carried out by completely replacing the high-pressure cylinder of the existing unit for a new high-pressure cylinder with ultra-supercritical steam parameters and superstructure with an additional intermediate-pressure cylinder while fully preserving the parameters and designs of the intermediate- and low-pressure output parts. Two options for modernization of the 300 MW series power unit thermal circuit structure were considered, and the scale of conversion of the regenerative feed water heating system was evaluated. In the first option of the thermal scheme, the 1st steam selection is organized from the cold threads of the modernized high-pressure cylinder with ultra-supercritical steam parameters, and the 2nd one – from the cold threads of the additional intermediate-pressure cylinder. In this case, two high-pressure heaters and a turbo drive of the feed pump are subject to replacement. The disadvantage of this option is that due to a significant increase in steam parameters, it is impossible to choose high-pressure heaters from the existing model range, and a new design must be developed. The electrical efficiency for this modernization option increases from 36.5% (the initial thermal circuit of the K-300-240-2 turbine) to 42.5%. In the second option, it is proposed to install an additional turbine with a capacity of 3 MW, to the input of which a steam from cold threads of the high-pressure cylinder with ultra-supercritical steam parameters is supplied with a loss equal to the sum of the 1st and 2nd selections of the original version of the turbine, on the same shaft with a turbo drive of the feed pump for the sake of preserving the existing high-pressure heater. The steam from the additional turbine selections goes to high-pressure heaters HPH9 and HPH8 with parameters corresponding to the output data of the existing turbine. Taking this into account, high-pressure heaters will not be replaceable. In addition, the power of the additional turbine is sufficient to ensure the operation of the feed pump together with the turbo drive of the feed pump to obtain a water pressure of 34 MPa. In view of this, the turbo drive of the feed pump also remains unchanged, except for the additional turbine installation. The electrical efficiency for the second option of the modernization scheme of the K-300-240-2 power unit is 42.4%. It was determined that the payback period of the modernization according to the first option is 5 years, taking into account the modernization of the boiler unit, and according to the second one – 4.5 years. It is proposed to choose the option of the thermal scheme with an additional turbine, since in this case it is possible to modernize the K-300-240-2 power unit with the maximum possible preservation of the regenerative feed water heating system while increasing its energy efficiency by almost 14%.
A new approach to the preparation of a nanosized sorbent based on magnesium phosphate has been developed. The patterns of copper(II) ions sorption with nanosized magnesium phosphate from aqueous ...solutions have been investigated. The sorption parameters have been determined, and the kinetics and mechanism of the processes have been elucidated. The high sorption ability of the nanoscale sorbent has been shown in comparison with existing sorbents based on magnesium phosphate.
The electron impact mass spectra of 1-R-substituted 3-alkoxy-2-(propargylsulfanyl)- and 3-alkoxy-2-(allenylsulfanyl)-1
H
-pyrroles (R = Me,
i
-Pr,
s
-Bu, Ph) have been studied for the first time. ...These compounds give rise to stable molecular ions whose primary fragmentation follows three competing pathways: cleavage of the C–O bonds with expulsion of alkyl radical, cleavage of the C–S bonds with formation of
M
–C
3
H
3
+
ions, and cleavage of the C–N bonds with synchronous hydrogen transfer to give odd-electron
M
–C
n
H
2n
+ · ion. The main fragmentation pathway of 2-(propargylsulfanyl) derivatives is cleavage of the C–S bond with formation of
M
–C
3
H
3
+
ion.
