1,139 results on '"A. P. Vasil’ev"'
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2. On finite groups isospectral to groups with abelian Sylow $2$-subgroups
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Grechkoseeva, M. A. and Vasil'ev, A. V.
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Mathematics - Group Theory ,20D60, 20D06, 20D08 - Abstract
The spectrum of a finite group is the set of orders of its elements. We are concerned with finite groups having the same spectrum as a direct product of nonabelian simple groups with abelian Sylow $2$-subgroups. For every positive integer $k$, we find $k$ nonabelian simple groups with abelian Sylow 2-subgroups such that their direct product is uniquely determined by its spectrum in the class of all finite groups. On the other hand, we prove that there are infinitely many finite groups having the same spectrum as the direct cube of the small Ree group $^2G_2(q)$, $q>3$, or the direct fourth power of the sporadic group $J_1$., Comment: 8 pages
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- 2024
3. The automorphism groups of small affine rank 3 graphs
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Guo, Jin, Vasil'ev, Andrey V., and Wang, Rui
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Mathematics - Combinatorics ,Mathematics - Group Theory ,20B25, 05E18, 05E30 - Abstract
A rank 3 graph is an orbital graph of a rank 3 permutation group of even order. Despite the classification of rank 3 graphs being complete, see, e.g., Chapter 11 of the recent monograph 'Strongly regular graphs' by Brouwer and Van Maldeghem, the full automorphism groups of these graphs (equivalently, the 2-closures of rank 3 groups) have not been explicitly described, though a lot of information on this subject is available. In the present note, we address this problem for the affine rank 3 graphs. We find the automorphism groups for finitely many relatively small graphs and show that modulo known results, this provides the full description of the automorphism groups of the affine rank 3 graphs, thus reducing the general problem to the case when the socle of the automorphism group is nonabelian simple.
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- 2024
4. Closures of permutation groups with restricted nonabelian composition factors
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Ponomarenko, Ilia, Skresanov, Saveliy V., and Vasil'ev, Andrey V.
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Mathematics - Group Theory ,20B05 (Primary) 20B25, 20G40 (Secondary) - Abstract
Given a permutation group $G$ on a finite set $\Omega$, let $G^{(k)}$ denote the $k$-closure of $G$, that is, the largest permutation group on $\Omega$ having the same orbits in the induced action on $\Omega^k$ as $G$. Recall that a group is $\mathrm{Alt}(d)$-free if it does not contain a section isomorphic to the alternating group of degree $d$. Motivated by some problems in computational group theory, we prove that the $k$-closure of an $\mathrm{Alt}(d)$-free group is again $\mathrm{Alt}(d)$-free for $k \geq 4$ and $d \geq 25$., Comment: 20 pages
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- 2024
5. The structure of a finite group and the maximum $\pi$-index of its elements
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Liu, A-Ming and Vasil'ev, Andrey V.
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Mathematics - Group Theory ,20E45, 20D20 - Abstract
Given a set of primes $\pi$, the $\pi$-index of an element $x$ of a finite group $G$ is the $\pi$-part of the index of the centralizer of $x$ in $G$. If $\pi=\{p\}$ is a singleton, we just say the $p$-index. If the $\pi$-index of $x$ is equal to $p_1^{k_1}\ldots p^{k_s}$, where $p_1,\ldots,p_s$ are distinct primes, then we set $\exp_\pi(x)=k_1+\ldots+k_s$. In this short note, we study how the number $\epsilon_\pi(G)=\max\{\epsilon_\pi(x):x\in G\}$ restricts the structure of the factor group $G/Z(G)$ of $G$ by its center. First, for a finite group $G$, we prove that $\phi_p(G/Z(G))\leq\epsilon_p(G)$, where $\phi_p(G/Z(G))$ is the Frattini length of a Sylow $p$-subgroup of $G/Z(G)$. Second, for a $\pi$-separable finite group $G$, we prove that $l_\pi(G/Z(G))\leq\epsilon_\pi(G)$, where $l_{\pi}(G/Z(G))$ is the $\pi$-length of $G/Z(G)$.
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- 2024
6. On recognition of the direct squares of the simple groups with abelian Sylow 2-subgroups
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Li, Tao, Moghaddamfar, A. R., Vasil'ev, Andrey V., and Wang, Zhigang
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Mathematics - Group Theory ,20D60, 20D06 - Abstract
The spectrum of a group is the set of orders of its elements. Finite groups with the same spectra as the direct squares of the finite simple groups with abelian Sylow 2-subgroups are considered. It is proved that the direct square $J_1\times J_1$ of the sporadic Janko group $J_1$ and the direct squares ${^2}G_2(q)\times{^2}G_2(q)$ of the simple small Ree groups ${^2}G_2(q)$ are uniquely characterized by their spectra in the class of finite groups, while for the direct square $PSL_2(q)\times PSL_2(q)$ of a 2-dimensional simple linear group $PSL_2(q)$, there are always infinitely many groups (even solvable groups) with the same spectra.
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- 2023
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7. Dependence of the Structure of Segregations on the Excess Volume of Intergranular Boundaries
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Lomaev, S. L. and Vasil’ev, L. S.
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- 2024
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8. On computing the closures of solvable permutation groups
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Ponomarenko, Ilia and Vasil'ev, Andrey V.
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Mathematics - Group Theory ,20B25, 20B40 ,F.2.2 - Abstract
Let $m\ge 3$ be an integer. It is proved that the $m$-closure of a given solvable permutation group of degree $n$ can be constructed in time $n^{O(m)}$., Comment: 7 pages
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- 2023
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9. On the Generalized Fitting Height and Nonsoluble Length of the Mutually Permutable Products of Finite Groups
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Murashka, Viachaslau I. and Vasil'ev, Alexander F.
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Mathematics - Group Theory ,20D40, 20D25 - Abstract
The generalized Fitting height $h^*(G)$ of a finite group $G$ is the least number $h$ such that $\mathrm{F}_h^* (G) = G$, where $\mathrm{F}_{(0)}^* (G) = 1$, and $\mathrm{F}_{(i+1)}^*(G)$ is the inverse image of the generalized Fitting subgroup $\mathrm{F}^*(G/\mathrm{F}^*_{(i)} (G))$. Let $p$ be a prime, $1=G_0\leq G_1\leq\dots\leq G_{2h+1}=G$ be the shortest normal series in which for $i$ odd the factor $G_{i+1}/G_i$ is $p$-soluble (possibly trivial), and for $i$ even the factor $G_{i+1}/G_i$ is a (non-empty) direct product of nonabelian simple groups. Then $h=\lambda_p(G)$ is called the non-$p$-soluble length of a group $G$. We proved that if a finite group $G$ is a mutually permutable product of of subgroups $A$ and $B$ then $\max\{h^*(A), h^*(B)\}\leq h^*(G)\leq \max\{h^*(A), h^*(B)\}+1$ and $\max\{\lambda_p(A), \lambda_p(B)\}= \lambda_p(G)$. Also we introduced and studied the non-Frattini length., Comment: arXiv admin note: substantial text overlap with arXiv:2103.13354
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- 2023
10. Organophosphorus S-adenosyl-L-methionine mimetics: synthesis, stability, and substrate properties
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Alexander Yu Rudenko, Sofia S. Mariasina, Anastasiia K. Bolikhova, Maxim V. Nikulin, Ratislav M. Ozhiganov, Vasiliy G. Vasil’ev, Yuri A. Ikhalaynen, Anastasia L. Khandazhinskaya, Maxim A. Khomutov, Peter V. Sergiev, Alex R. Khomutov, and Vladimir I. Polshakov
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S-adenosyl-L-methionine ,SAM analogs ,halide methyltransferase ,MAT2A ,COMT ,WBSCR27 ,Chemistry ,QD1-999 - Abstract
S-Adenosyl-l-methionine (SAM)-mediated methylation of biomolecules controls their function and regulates numerous vital intracellular processes. Analogs of SAM with a reporter group in place of the S-methyl group are widely used to study these processes. However, many of these analogs are chemically unstable that largely limits their practical application. We have developed a new compound, SAM-PH, which contains an H-phosphinic group (-P(O)(H)OH) instead of the SAM carboxylic group. SAM-PH is significantly more stable than SAM, retains functional activity in catechol-O-methyltransferase and methyltransferase WBSCR27 reactions. The last is associated with Williams–Beuren syndrome. Rac-SAM-PH was synthesized chemically, while (R,S)-SAM-PH and its analogs were prepared enzymatically either from H-phosphinic analogs of methionine (Met-PH) or H-phosphinic analog of S-adenosyl-l-homocysteine (SAH-PH) using methionine adenosyltransferase 2A or halide methyltransferases, respectively. SAH-PH undergoes glycoside bond cleavage in the presence of methylthioadenosine nucleosidase like natural SAH. Thus, SAM-PH and its analogs are promising new tools for investigating methyltransferases and incorporating reporter groups into their substrates.
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- 2024
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11. On recognition of direct powers of finite simple linear groups by spectrum
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Yang, N., Gorshkov, I. B., Staroletov, A. M., and Vasil'ev, A. V.
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Mathematics - Group Theory ,20D06 - Abstract
The spectrum of a finite group is the set of its element orders. We give an affirmative answer to Problem 20.58(a) from the Kourovka Notebook proving that for every positive integer $k$, the $k$-th direct power of the simple linear group $L_{n}(2)$ is uniquely determined by its spectrum in the class of finite groups provided $n$ is a power of $2$ greater than or equal to $56k^2$., Comment: 17 pages
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- 2022
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12. Evaluation of the Residual Strength of Composite Products Based on the Structural-Phenomenological Concept of Damage and Acoustic Emission Diagnostics
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Matvienko, Yu. G., Makhutov, N. A., Vasil’ev, I. E., Chernov, D. V., Ivanov, V. I., and Elizarov, S. V.
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- 2023
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13. Hydrogenation-Induced Modification of the Crystal Structure of Fe/Gd Superlattices
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Likhachev, I. A., Subbotin, I. A., Chesnokov, Yu. M., Devyaterikov, D. I., Kondrat’ev, O. A., Ryzhova, A. A., Salamatov, Yu. A., Milyaev, M. A., Vasil’ev, A. L., Kravtsov, E. A., and Pashaev, E. M.
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- 2023
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14. Excitation of Cylindrical Detonation by a Decaying Shock Wave
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Boriskin, A. A. and Vasil’ev, A. A.
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- 2023
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15. Magnetic Properties of Fe1 –xCoxCr2S4 Solid Solutions in the FeCr2S4-Rich Region
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Shabunina, G. G., Busheva, E. V., Vasil’ev, P. N., Efimov, N. N., and Denishchenko, A. D.
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- 2023
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16. On embedding theorems for $\mathfrak{X}$-subgroups
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Guo, Wenbin, Revin, Danila O., and Vasil'ev, Andrey V.
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Mathematics - Group Theory ,20E28, 20D20, 20D35 - Abstract
Let $\mathfrak{X}$ be a class of finite groups closed under subgroups, homomorphic images, and extensions. We study the question which goes back to the lectures of H. Wielandt in 1963-64: For a given $\mathfrak{X}$-subgroup $K$ and maximal $\mathfrak{X}$-subgroup $H$, is it possible to see embeddability of $K$ in $H$ (up to conjugacy) by their projections onto the factors of a fixed subnormal series. On the one hand, we construct examples where $K$ has the same projections as some subgroup of $H$ but is not conjugate to any subgroup of $H$. On the other hand, we prove that if $K$ normalizes the projections of a subgroup $H$, then $K$ is conjugate to a subgroup of $H$ even in the more general case when $H$ is a submaximal $\mathfrak{X}$-subgroup.
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- 2022
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17. The minimal size of a generating set for primitive $\frac{3}{2}$-transitive groups
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Churikov, Dmitry, Vasil'ev, Andrey V., and Zvezdina, Maria A.
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Mathematics - Group Theory ,20B05, 20B15, 20B20 - Abstract
We refer to $d(G)$ as the minimal cardinality of a generating set of a finite group $G$, and say that $G$ is $d$-generated if $d(G)\leq d$. A transitive permutation group $G$ is called $\frac{3}{2}$-transitive if a point stabilizer $G_\alpha$ is nontrivial and its orbits distinct from $\{\alpha\}$ are of the same size. We prove that $d(G)\leq4$ for every primitive $\frac{3}{2}$-transitive permutation group $G$, moreover, $G$ is $2$-generated except for the very particular solvable affine groups that we completely describe. In particular, all finite $2$-transitive and $2$-homogeneous groups are $2$-generated. We also show that every finite group whose abelian subgroups are cyclic is $2$-generated, and so is every Frobenius complement.
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- 2022
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18. Criterion of nonsolvability of a finite group and recognition of direct squares of simple groups
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Wang, Zh., Vasil'ev, A. V., Grechkoseeva, M. A., and Zhurtov, A. Kh.
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Mathematics - Group Theory ,20D60, 20D06, 20E34 - Abstract
The spectrum $\omega(G)$ of a finite group $G$ is the set of orders of its elements. The following sufficient criterion of nonsolvability is proved: if among the prime divisors of the order of a group $G$, there are four different primes such that $\omega(G)$ contains all their pairwise products but not a product of any three of these numbers, then $G$ is nonsolvable. Using this result, we show that for $q\geqslant 8$ and $q\neq 32$, the direct square $Sz(q)\times Sz(q)$ of the simple exceptional Suzuki group $Sz(q)$ is uniquely characterized by its spectrum in the class of finite groups, while for $Sz(32)\times Sz(32)$, there are exactly four finite groups with the same spectrum., Comment: In the third version, Theorem 1 is slightly reformulated and some references are corrected
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- 2022
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19. Approximation of an Arbitrary Function by a Piecewise Constant Function and Number of Theoretical Separation Stages in A Rectification Tower
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Tsirlin, A. M., Balunov, A. I., and Vasil’ev, A. M.
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- 2023
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20. VII All-Russian Lower Volga Archaeological Conference
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Dmitriy V. Vasil’ev
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archeology ,lower volga archaeological conference ,nomads ,golden horde ,epoch of stone ,astrakhan state university ,History of Civilization ,CB3-482 ,Archaeology ,CC1-960 ,Anthropology ,GN1-890 - Abstract
The article summarizes the results of the 7th All-Russian Lower Volga Archaeological Conference. The conference was held in Astrakhan in in October 2023 on the base of Astrakhan State University.
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- 2023
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21. On Cayley representations of central Cayley graphs over almost simple groups
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Guo, Jin, Guo, Wenbin, Ryabov, Grigory, and Vasil'ev, Andrey V.
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Mathematics - Group Theory ,Mathematics - Combinatorics ,05C60, 05E18, 20B35, 20D06 - Abstract
A Cayley graph over a group $G$ is said to be central if its connection set is a normal subset of $G$. We prove that every central Cayley graph over a simple group $G$ has at most two pairwise nonequivalent Cayley representations over $G$ associated with the subgroups of $Sym(G)$ induced by left and right multiplications of $G$. We also provide an algorithm which, given a central Cayley graph $\Gamma$ over an almost simple group $G$ whose socle is of a bounded index, finds the full set of pairwise nonequivalent Cayley representations of $\Gamma$ over $G$ in time polynomial in size of $G$., Comment: 10 pages
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- 2021
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22. Finite groups isospectral to simple groups
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Grechkoseeva, Maria A., Mazurov, Victor D., Shi, Wujie, Vasil'ev, Andrey V., and Yang, Nanying
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Mathematics - Group Theory ,20D05, 20D60 - Abstract
The spectrum of a finite group is the set of element orders of this group. The main goal of this paper is to survey results concerning recognition of finite simple groups by spectrum, in particular, to list all finite simple groups for which the recognition problem is solved., Comment: Numbering of theorems, lemmas and other assertions has been changed to match that of the version published in Commun. Math. Stat
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- 2021
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23. Intravital Position Study of the Clinical Anatomy of the Middle Lobe and Superior Poles of the Thyroid Gland
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Vladislav V. Tatarkin, Andrey I. Shchegolev, Aleksandr M. Bakunov, Yuriy L. Vasil’ev, Mikhail D. Chernyshev, Evgeniy A. Serebryakov, Ksenia L. Kaplieva, Egor O. Stetsik, Tahmina Pulotova, Ellina V. Velichko, and Evgeniy M. Trunin
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positional anatomy ,thyroid lobe ,thyroid gland ,neck MRI ,Medicine (General) ,R5-920 - Abstract
Background and Objectives: This study analyzes the issues of position dislocation of the head of the superior poles and lateral points of the outer edge of the middle divisions of each of the thyroid lobes (TL) changes. The purpose was to provide an intravital position study of the clinical anatomy of the middle and superior poles of the thyroid gland (TG). Materials and Methods: We used data on anthropometry obtained during the study and data from MRI of the neck organs and anatomical formations of 100 healthy individuals, comprising 55 (55%) female and 45 (45%) male participants. To evaluate the data obtained in the examined group, the minimum probability value was 0.95 (95% confidence interval or p < 0.05). Results: Maximum flexion of the neck the distance from the center of the jugular notch to the lateral points of the outer edge of the middle parts of the TL decreases in all groups of but mostly in male ectomorphs; the same distance to the superior poles of the TG changes most in ectomorphic males on the right by 38.9% (p value < 0.001) and mesomorphic females on the left by 37.8% (p value < 0.001); in rotation to the left, the maximum was found in male ectomorphs, which decreased by 9.5% on the left (p value < 0.001) and by 7.3% on the right (p value < 0.001). Conclusions: this study provided new information about the intravital anatomy of the TG position, of the superior poles, and the lateral points of the middle part of its lobes.
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- 2024
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24. Design rules for time of flight Positron Emission Tomography (ToF-PET) heterostructure radiation detectors
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Krause, Philip, Rogers, Edith, Birowosuto, Muhammad Danang, Pei, Qibing, Auffray, Etiennette, Vasil'ev, Andrey N, and Bizarri, Gregory
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Nuclear and Plasma Physics ,Physical Sciences ,Generic health relevance ,Affordable and Clean Energy ,Heterostructured radiation detector ,Ultra-fast timing ,Positron Emission tomography - Abstract
Despite the clinical acceptance of ToF-PET, there is still a gap between the technology's performance and the end-user's needs. Core to bridging this gap is the ability to develop radiation detectors combining a short attenuation length and a sub-nanosecond time response. Currently, the detector of choice, Lu2SiO5:Ce3+ single crystal, is not selected for its ability to answer the performance needs, but as a trade-off between requirements and availability. To bypass the current performance limitations, in particular restricted time response, the concept of the heterostructured detector has been proposed. The concept aims at splitting the scintillation mechanisms across two materials, one acting primarily as an absorber and one as an ultra-fast emitter. If the concept has attracted the interest of the medical and material communities, little has been shown in terms of the benefits/limitations of the approach. Based on Monte Carlo simulations, we present a survey of heterostructure performance versus detector design. The data allow for a clear understanding of the design/performance relationship. This, in turn, enables the establishment of design rules toward the development and optimization of heterostructured detectors that could supersede the current detector technology in the medical imaging field but also across multiple sectors (e.g. high-energy physics, security).
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- 2022
25. On the prime graph of a finite group with unique nonabelian composition factor
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Grechkoseeva, Maria A. and Vasil'ev, Andrey V.
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Mathematics - Group Theory ,20D60, 20D06 - Abstract
We say that finite groups are isospectral if they have the same sets of orders of elements. It is known that every nonsolvable finite group $G$ isospectral to a finite simple group has a unique nonabelian composition factor, that is, the quotient of $G$ by the solvable radical of $G$ is an almost simple group. The main goal of this paper is prove that this almost simple group is a cyclic extension of its socle. To this end, we consider a general situation when $G$ is an arbitrary group with unique nonabelian composition factor, not necessarily isospectral to a simple group, and study the prime graph of $G$, where the prime graph of $G$ is the graph whose vertices are the prime numbers dividing the order of $G$ and two such numbers $r$ and $s$ are adjacent if and only if $r\neq s$ and $G$ has an element of order $rs$. Namely, we establish some sufficient conditions for the prime graph of such a group to have a vertex adjacent to all other vertices. Besides proving the main result, this allows us to refine a recent result by P. Cameron and N. Maslova concerning finite groups almost recognizable by prime graph.
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- 2021
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26. The closures of wreath products in product action
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Ponomarenko, I. and Vasil'ev, A. V.
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Mathematics - Group Theory ,20B10 20B25 - Abstract
Let $m$ be a positive integer and let $\Omega$ be a finite set. The $m$-closure of $G\le$Sym$(\Omega)$ is the largest permutation group on $\Omega$ having the same orbits as $G$ in its induced action on the Cartesian product $\Omega^m$. The exact formula for the $m$-closure of the wreath product in product action is given. As a corollary, a sufficient condition is obtained for this $m$-closure to be included in the wreath product of the $m$-closures of the factors., Comment: 7 pages
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- 2021
27. Optimization and validation of flow cytometry method for quantification of SARS-CoV-2 antigen-reactive human memory T cells
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Olga M. Strizhakova, Andrey S. Pershin, Alexander A. Kazarov, Ivan V. Lyagoskin, Yana A. Bahareva, Alexander P. Vasil'ev, Yulia A. Nikonova, Irina Yu. Egorova, Rahim R. Shukurov, and Ravil A. Khamitov
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sars-cov-2 ,t-cells immunity ,covid-19 ,coronavirus peptides ,flow cytometry ,intracellular cytokine staining ,validation ,Infectious and parasitic diseases ,RC109-216 - Abstract
A proper and representative monitoring of SARS-CoV-2 herd immunity including a long-term health impact on recovered patients and vaccinated individuals is of great importance. For this, a monitoring campaign should assesses both humoral and T-cell immune arms. Upon that, analyzing antigen specific-cell activation and cellular phenotype are informative. We developed a flow cytometry method for detection of intracellular IFN-producing antigen-reactive T cells after exposure of human peripheral blood mononuclear cells (PBMC) to SARS-CoV-2 virus antigens. The method was validated according to the following characteristics: sensitivity, specificity, precision, and robustness. We used positive samples from donors recovered from COVID-19 and negative samples from donors who had no contact with COVID-19 patients and lacking antibodies to SARS-CoV-2. All samples were tested by laboratory methods. Peripheral blood mononuclear cells were isolated from donor blood by centrifugation in a Ficoll density gradient. Specific T cells were stimulated with S-protein as well as N, M, ORF3a, and ORF7a protein peptides to count IFN-producing T cells by flow cytometer. The data were statistically analyzed. The area limited by ROC-curve and false positive rate (AUC) for CD4 and CD8 cells was from 0.97 to 1.00. Precision was considered acceptable because the coefficient of variation for all PBCM did not exceed 20%. Robustness was confirmed for frozen and freshly prepared PBMC samples. The thresholds levels to recognize immune and non-immune samples were defined for CD4-positive T-cells (0.029%) and CD8-positive T-cells (0.0640.068%). Also, acceptance criteria for positive and negative controls were defined. Based on the validation, the suitability of the method Evaluation of antigen-reactive T cells that produce intracellular IFN in response to SARS-CoV-2 virus antigens by flow cytometry was confirmed. The method allows for reliable data that was used to characterize standard control samples for internal quality control of TigraTest SARS-CoV-2 kits.
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- 2023
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28. Effect of yttrium doping on the photocatalytic properties of ZnO thin films
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L. Hrytsak, B. Turko, V. Vasil’ev, Y. Eliyashevskyy, A. Kostruba, and A. Hrytsak
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zinc oxide ,photocatalysis ,photodegradation ,absorption spectra ,Physics ,QC1-999 - Abstract
Zinc oxide films with different levels of yttrium doping are deposited on glass substrates, using radio-frequency magnetron sputtering. Photocatalytic properties were investigated for such Y-doping weight concentration: 0, 2.4, 3.9, 4.7 wt. %. The studies showed that the Y-doping significantly improves the photocatalytic activity of the ZnO thin films. It was shown that the ZnO:Y 3.9 wt. % presents the highest degradation efficiency of 100 % during 80 minutes and the largest rate constant 9.6 · 10-2 min-1 among all samples.
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- 2023
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29. Crystal Structure and Thermodynamic Properties of the RGaTi2O7 (R = Sm, Ho, Tm, Yb) Titanates
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Denisova, L. T., Chumilina, L. G., Kargin, Yu. F., Vasil’ev, G. V., Beletskii, V. V., and Denisov, V. M.
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- 2023
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30. Fitting like subgroups of finite groups
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Murashka, Viachaslau I. and Vasil'ev, Alexander F.
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Mathematics - Group Theory ,20D25, 20F17, 20F19 - Abstract
In this paper the concept of $\mathbb{F}$-functorial of a finite group was introduced. These functorials have many properties of the Fitting subgroup of a soluble group and the generalized Fitting subgroup of a finite group. It was shown that the set of all $\mathbb{F}$-functorials is a complete distributive lattice and the cardinality of this lattice is continuum. The sharp bounds on the generalized Fitting height of mutually permutable product of two subgroups were obtained.
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- 2021
31. A generalization of Hall's theorem on hypercenter
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Murashka, Viachaslau I. and Vasil'ev, Alexander F.
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Mathematics - Group Theory ,Primary 20D25, Secondary 20F17, 20F19 - Abstract
Let $ \sigma$ be a partition of the set of all primes and $\mathfrak{F}$ be a hereditary formation. We described all formations $\mathfrak{F}$ for which the $\mathfrak{F}$-hypercenter and the intersection of weak $K$-$\mathfrak{F}$-subnormalizers of all Sylow subgroups coincide in every group. In particular the formation of all $\sigma$-nilpotent groups has this property. With the help of our results we solve a particular case of L.A.~Shemetkov's problem about the intersection of $\mathfrak{F}$-maximal subgroups and the $\mathfrak{F}$-hypercenter. As corollaries we obtained P. Hall's and R. Baer's classical results about the hypercenter. We proved that the non-$\sigma$-nilpotent graph of a group is connected and its diameter is at most 3., Comment: arXiv admin note: substantial text overlap with arXiv:2009.04720. In this version Theorem 1 is improved and a new application of the main result is added
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- 2021
32. Quantitative 1H NMR Spectroscopy Method for Determination of Anthraquinone Derivatives in Extracts from Rubia tinctorum L. Roots and Rhizomes
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Vasilii Vasil’ev, Anzhelika Sheremeta, Vasilii Ivlev, Sergey Goriainov, Fadi Hajjar, Cesar Esparza, Evgeniy Platonov, Arkadiy Khromov, Alexandr Kolesnov, Victoria Romashchenko, and Gennady Kalabin
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ruberythric acid ,lucidin-3-primeveroside ,qNMR ,Rubia tinctorum L. roots and rhizome ,Pharmacy and materia medica ,RS1-441 - Abstract
The roots and rhizomes of Rubia tinctorum L. have been widely used both for industrial and medicinal purposes for centuries. The primary biologically active substances from Rubia tinctorum L. roots and rhizomes are anthraquinone derivatives such as ruberythric acid and lucidin-3-primeveroside. Their identification and quantification are carried out by various analytical methods, requiring a complicated sample preparation as well as special reagents and reference samples. However, NMR spectroscopy has no limitations of this kind. In this work, we have developed and validated a new express and standard-free method for the qualitative and quantitative analysis of ruberythric acid and lucidin-3-primeveroside by 1H NMR spectroscopy in the extracts from the roots and rhizomes of Rubia tinctorum L. In this work, we have optimized the conditions of the sample preparation and registration of 1H NMR spectra, determined the optimal solvent and reference compound and confirmed the obtained results by HPLC-UV-MS.
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- 2024
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33. The Pterygomandibular Space: A Volumetric Evaluation Using the Novel A-Silicone Injections Method
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Hadi Darawsheh, Ali Alsaegh, Elena Kanukoeva, Rinat Saleev, Gulshat Saleeva, Beatrice Volel, Natalia Kireeva, Ekaterina Rebrova, and Yuriy L. Vasil’ev
- Subjects
anatomy ,anesthesia ,dentistry ,local anesthesia ,mandibular nerve ,pterygomandibular space ,Medicine (General) ,R5-920 - Abstract
Inferior alveolar nerve block (IANB) is one of the most common procedures in operative dentistry, and a deep understanding of the normal anatomical variation of the pterygomandibular space (PM) is essential for its safe and successful administration. This cadaveric anatomical study aimed to use A-silicone injections to evaluate the volume of the PM. This study was conducted using 46 human cadaver heads (25 males and 21 females). A craniometric analysis was performed using the cadavers’ ages, the number of silicone cartridges (carpules) used to fill the pterygomandibular space, Izard’s Facial Index (FI), and the Cranial Index (CI). A Halstead mandibular block was performed by injecting 1.7 mL A-silicone cartridges (as an equivalent to standard local aesthetic carpules volume) into the PM. The cured silicone was extracted from the dissected mandibles. The volume (length, width, and thickness) of the extracted silicone and the number of silicone cartridges used to fill the space were evaluated. The results showed that there are statistically significant positive correlations between the CI and the width of the right PM, as well as the width and length of the left PM. A statistically significant correlation was found between the width of the left PM and the age of the cadaveric heads; the higher the age, the thicker the space on both sides. The volume of the PM corresponded to 1.5 cartridges on average.
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- 2024
- Full Text
- View/download PDF
34. The $3$-closure of a solvable permutation group is solvable
- Author
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O'Brien, E. A., Ponomarenko, I., Vasil'ev, A. V., and Vdovin, E.
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Mathematics - Group Theory ,20B05 - Abstract
Let $m$ be a positive integer and let $\Omega$ be a finite set. The $m$-closure of $G\leq\operatorname{Sym}(\Omega)$ is the largest permutation group on $\Omega$ having the same orbits as $G$ in its induced action on the Cartesian product $\Omega^m$. The $1$-closure and $2$-closure of a solvable permutation group need not be solvable. We prove that the $m$-closure of a solvable permutation group is always solvable for $m\geq3$.
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- 2020
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- View/download PDF
35. Thermodynamic Entropy Balances in Perfect Mixing Apparatuses
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Tsirlin, A. M. and Vasil’ev, A. M.
- Published
- 2023
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- View/download PDF
36. Modern concepts of the mechanisms of congenital cytomegalovirus infection development
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V. V. Vasil’ev, N. V. Rogozina, and I. V. Markin
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congenital infection ,cytomegalovirus ,pregnant women ,pathogenesis ,Infectious and parasitic diseases ,RC109-216 - Abstract
The review presents modern information of domestic and foreign authors about possible pathogenetic mechanisms of the virus effect on the fetus in the case of cytomegalovirus infection in pregnant women. Immunosuppressive changes, which are a feature of the physiological course of pregnancy, create favorable conditions for the development of active cytomegalovirus infection. The virus’s ability to infect a wide range of cells in vivo and trigger a set of molecular mechanisms causes changes in placental cell differentiation, which plays a key role in transplant transmission. The processes of formation of chronic placental insufficiency, which leads to hypoxia of the fetus and to delay of intrauterine development, are separately highlighted. The literary data on non-specific metabolic changes of the mother and placental activation of proinflammatory cytokines (TNF-α, IL-1β, IL2, IL-6 and IL-8), which occur in cytomegalovirus infection and are of significant importance in formation of hypoxia of the fetus have been analyzed.In addition, the role of individual cells in preventing intrauterine infection is examined, namely the deciduous macrophages with antiviral activity, the deciduous natural killers and their activated toll-like receptors. The article also discusses the genetic predisposition to the development of manifest forms of EID, including the relationship of polymorphism of TLR2 and Arg753Gln genes with an increased risk of intrauterine infection of the fetus CMV.Characteristic properties of the virus are pronounced genetic diversity, the ability to life-long persistence in various human organs and tissues (secretory glands, lymphatic cells, kidneys, etc.) and replication without cell damage, as well as suppressing cellular immunity. The article describes the issues of genotyping of virus and the relationship of some genotypes with certain organ pathology in newborns.
- Published
- 2023
- Full Text
- View/download PDF
37. Comparative evaluation of scales to determine severity of acute pancreatitis
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A. N. Shcherbyuk, S. V. Morozov, A. I. Lobakov, E. E. Kruglov, V. M. Manuylov, S. S. Dydykin, E. V. Blinova, K. A. Zhandarov, R. D. Meylanova, O. V. Drakina, O. V. Kyt'ko, Yu. L. Vasil'ev, M. V. Nelipa, P. V. Panyushkin, P. V. Kryuchko, and M. D. Kolesnichenko
- Subjects
acute pancreatitis ,apach ii scale ,acute pancreatitis hazard index ,therapeutic fasting ,Medicine (General) ,R5-920 - Abstract
Based on the method developed by the authors for quantifying the severity of patients with acute pancreatitis, a method for calculating the duration of therapeutic fasting in a particular patient has been created. We studied the medical histories of 500 patients with acute pancreatitis who were in two medical hospitals from 2010 to 2021. They underwent complex therapy of acute pancreatitis. Based on the dependence found using multivariate regression analysis using the universal statistical software package StatSoft Statistica for OC Windows, the authors previously developed and published a method for calculating the severity of a patient's condition with acute pancreatitis in the enzymatic toxemia phase. This method in the process of practical application was significantly improved by the authors and called the IDAP scale (ACUTE PANCREATITIS HAZARD INDEX). The advantages of this method: the calculation of the severity of the patient's condition can be made at any time of interest, the indicators are included in the Medical and Economic standards of the Russian Federation for acute pancreatitis, it is enough to use the standard office program MS Excel, which is available to any practicing physician. When comparing the results of assessing the severity of patients on the IDAP and APACH II scales, no discrepancies of more than 15% were found in 640 measurements in 50 patients, which allowed us to use the IDAP system in our study on a par with the generally accepted APACH II. At the second stage of the study, as a result of the analysis of 86 clinical observations using the technique of multidimensional regression analysis, a relationship was found between the clinical severity of the patient upon admission to the hospital for treatment, the severity at a given time and the required duration of therapeutic fasting (in days). At the second stage of the study, as a result of the analysis of 86 clinical observations using the technique of multidimensional regression analysis, a relationship was found between the clinical severity of the patient upon admission to the hospital for treatment, the severity at a given time and the required duration of therapeutic fasting (in days). When using this method of calculating the duration of fasting, only 7 (8%) patients had an exacerbation of the process after the start of feeding them through the mouth. Thus, taking into account the coefficient of severity of the patient's condition with acute pancreatitis, it is possible to reliably determine the timing of therapeutic fasting in this disease.
- Published
- 2023
- Full Text
- View/download PDF
38. On some applications of Fitting like subgroups of finite groups
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Murashka, Viachaslau I. and Vasil'ev, Alexander F.
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Mathematics - Group Theory ,20D25 (Primary) 20F17, 20F19 (Secondary) - Abstract
In this paper we study the groups all whose maximal or all Sylow subgroups are $K$-$\mathfrak{F}$-subnormal in their product the with generalizations of the Fitting subgroup $\mathrm{F}^*(G)$ and $\mathrm{\tilde F}(G)$. We prove that a hereditary formation $\mathfrak{F}$ contains every group all whose Sylow subgroups are $K$-$\mathfrak{F}$-subnormal in their product with $\mathrm{F}^*(G)$ if and only if $\mathfrak{F}$ is the class of all $\sigma$-nilpotent groups for some partition $\sigma$ of the set of all primes. We obtain a new characterization of the $\sigma$-nilpotent hypercenter, i.e. the $\mathfrak{F}$-hypercenter and the normal largest subgroup which $K$-$\mathfrak{F}$-subnormalize all Sylow subgroups coincide if and only if $\mathfrak{F}$ is the class of all $\sigma$-nilpotent groups.
- Published
- 2020
39. A characterization of exceptional pseudocyclic association schemes by multidimensional intersection numbers
- Author
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Chen, Gang, He, Jiawei, Ponomarenko, Ilia, and Vasil'ev, Andrey
- Subjects
Mathematics - Combinatorics ,05E30, 05E18 - Abstract
Recent classification of $\frac{3}{2}$-transitive permutation groups leaves us with three infinite families of groups which are neither $2$-transitive, nor Frobenius, nor one-dimensional affine. The groups of the first two families correspond to special actions of ${\mathrm{PSL}}(2,q)$ and ${\mathrm{P\Gamma L}}(2,q),$ whereas those of the third family are the affine solvable subgroups of ${\mathrm{AGL}}(2,q)$ found by D. Passman in 1967. The association schemes of the groups in each of these families are known to be pseudocyclic. It is proved that apart from three particular cases, each of these exceptional pseudocyclic schemes is characterized up to isomorphism by the tensor of its $3$-dimensional intersection numbers., Comment: 16 pages
- Published
- 2020
40. Factoring nonabelian finite groups into two subsets
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Bildanov, Ravil, Goryachenko, Vadim, and Vasil'ev, Andrey
- Subjects
Mathematics - Group Theory ,20D60 - Abstract
A group $G$ is said to be factorized into subsets $A_1, A_2, \ldots, A_s\subseteq G$ if every element $g$ in $G$ can be uniquely represented as $g=g_1g_2\ldots g_s$, where $g_i\in A_i$, $i=1,2,\ldots,s$. We consider the following conjecture: for every finite group $G$ and every factorization $n=ab$ of its order, there is a factorization $G=AB$ with $|A|=a$ and $|B|=b$. We show that a minimal counterexample to this conjecture must be a nonabelian simple group and prove the conjecture for every finite group the nonabelian composition factors of which have orders less than $10\,000$.
- Published
- 2020
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- View/download PDF
41. New photoacids in microarray synthesis of oligonucleotides
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A.N. Sinyakov, E.V. Kostina, D.E. Zaytsev, N.V. Chukanov, G.N. Kamaev, V.P. Bessmeltsev, V.V. Shelkovnikov, and E.V. Vasil'ev
- Subjects
Microchip synthesizer of oligonucleotides ,Oxime sulfonate ,Photoacid generator ,Trityl cation ,Oligonucleotide ,Chemistry ,QD1-999 - Abstract
Photochemical activity of thiophene oxime esters and of sulfonium salt tris[4-(4-acetylphenyl)sulfanylphenyl]sulfonium tetrakis(2,3,4,5,6-pentafluorophenyl)boranuide (photoacid generator 290 [PAG 290]) was investigated in a reaction forming a trityl cation. Quantum yields of photoacid phototransformation reactions and of photodetritylation of 5′-O-(4,4′-dimethoxytrityl)thymidine were determined. Then, [(Z)-[(3Z)-3-[cyano(o-tolyl)methylene]-2-thienylidene]amino] 2,4,6-triisopropylbenzenesulfonate (H 365) and PAG 290 were used as detritylation photoactivators in a procedure of oligonucleotide synthesis on a microchip synthesizer prototype, and several oligonucleotides were synthesized. At the stage of oligonucleotide chain extension, the yield was 94–96%. The tested photoacids can be successfully applied to microchip synthesis of oligonucleotides.
- Published
- 2023
- Full Text
- View/download PDF
42. Two-closure of supersolvable permutation group in polynomial time
- Author
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Ponomarenko, Ilia and Vasil'ev, Andrey
- Subjects
Mathematics - Group Theory ,Computer Science - Computational Complexity ,Mathematics - Combinatorics ,20B25, 05E18 ,F.2.2 - Abstract
The $2$-closure $\overline{G}$ of a permutation group $G$ on $\Omega$ is defined to be the largest permutation group on $\Omega$, having the same orbits on $\Omega\times\Omega$ as $G$. It is proved that if $G$ is supersolvable, then $\overline{G}$ can be found in polynomial time in $|\Omega|$. As a byproduct of our technique, it is shown that the composition factors of $\overline{G}$ are cyclic or alternating of prime degree., Comment: 20 pages
- Published
- 2019
- Full Text
- View/download PDF
43. Magnetic Particles In Soils And Epiphytes In The Zone Of Influence Of A Ferrous Metallurgy Factory In The City Of Perm
- Author
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A. V. Bobrova and A. A. Vasil’ev
- Subjects
magnetic susceptibility ,heavy metals ,urban soils ,epiphytic mosses ,aerial pollution ,electron microscopic analysis ,Geography (General) ,G1-922 - Abstract
The intensification of industrial production leads to an increase in the technogenic impact on the environment. Minerals containing iron are sensitive to many environmental processes and analysis of the composition of magnetic particles is relevant in the study of environmental pollution. This study focused on urban soils of near-trunk circles and epiphytic mosses on Populus nigra L. in the territory of Motovilikhinsky district of Perm, where a metallurgical plant is located. In this work, using electron probe microanalysis and scanning electron microscopy, we analyzed the magnetic susceptibility (MS), morphology, and chemical composition of magnetic particles isolated from urban soils and epiphytic mosses. The content of heavy metals in the studied soils exceeds the clarkes of chemical elements (CCE) in the upper continental crust: Cr - 286 times, Mn - 15 times, Fe - 11 times, Ti - 4 times, Mg - 4 times. The study of the chemical composition of epiphytes made it possible to assess the contribution of aerial sources to soil pollution. The concentrations of metals in the magnetic particles of epiphytes also exceed the Clarke values: Cr - 3257 times, Fe - 8 times, Ti - 7 times, Mg - 4 times. The similarity of the morphology and chemical composition of the magnetic particles of soils and epiphytes indicate common sources of pollution. A comprehensive assessment of the state of the territory may include magneto-geochemical monitoring of the soil cover and monitoring of the magnetic state of epiphytes on Populus nigra L.
- Published
- 2023
- Full Text
- View/download PDF
44. Using Acoustic Emission and Video Recording for Monitoring the Kinetics of Damage under Compression of Composite Samples
- Author
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Matvienko, Yu. G., Vasil’ev, I. E., and Chernov, D. V.
- Published
- 2022
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- View/download PDF
45. Ce0.8Y0.2O2–δ — Effect of Production Method on Structure and Electrophysical Properties
- Author
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Sudzhanskaya, I. V., Vasil’ev, A. E., Yapryntsev, M. N., Nekrasova, Yu. S., and Oleinik, A. N.
- Published
- 2022
- Full Text
- View/download PDF
46. Clinical Anatomy of the Ligaments of the Face and Their Fundamental Distinguishing Features
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Artem Mirontsev, Olesya Andruschenko, Yuriy Vasil’ev, Elena Verbo, Liyana Kolesova, Ekaterina Blinova, Kirill Zhandarov, Mikhail Nelipa, Petr Panushkin, Ellina Velichko, Yulianna Enina, Zurab Bagatelia, and Sergey Dydykin
- Subjects
facial aging ,the ligaments of the face ,zygomatic ligament ,zygomaticus major muscle ,masseteric ligament ,mandibular ligament ,Medicine (General) ,R5-920 - Abstract
Our study aimed to clarify the anatomical features of the zygomatic, upper masseteric, lower masseteric and mandibular ligaments and their possible contribution to age-related gravitational ptosis. The study was carried out by the method of layered dissection of fresh cadavers. In several observations, the zygomatic ligament is represented by the fibers originating from the zygomaticus major muscle fibers. It is a true ligament with the fibers inserted directly into the skin. The upper and lower masseteric ligaments originate from the parotideomasseteric fascia and weave into the thickness of the SMAS. The mandibular ligament consists of two connective tissue laminae originating from the parotideomasseteric fascia at the lower edge of the mandible and from the inner surface of this fascia, along the anterior edge of the masseter muscle, skirting the facial vein sheath and the facial artery, traveling toward the platysma and the depressor anguli oris muscle, and merging with their fibers. The zygomatic ligament should be considered an osteo-musculocutaneous ligament, emphasizing the role of the associated zygomaticus major muscle in the mechanism of aging. The upper and lower masseteric and mandibular ligaments are false fascio-SMAS ligaments rather than osteo-cutaneous ones, playing the barrier role and fixing the superficial fascia and the platysma muscle.
- Published
- 2024
- Full Text
- View/download PDF
47. Morphological Evaluation and Immunohistochemical Analysis of the Reparative Potential of the Buccal Fat Pad
- Author
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Roman Zhidkov, Andrew Panin, Aleksei Drobyshev, Tatiana Demura, Sofya Avraamova, Petr Aleksandrov, Anastasia Kolesnikova, Hadi Darawsheh, Anna Turkina, Nicolai Redko, Yaroslav Skakunov, Elena Karpova, Anzhela Brago, Aleksandr Tsitsiashvili, and Yuriy Vasil’ev
- Subjects
oroantral communication ,buccal fat pad ,mesenchymal stem cells ,immunohistochemistry ,morphology ,Medicine (General) ,R5-920 - Abstract
Background and Objectives: There are many surgical techniques for oroantral communication treatment, one of which is the buccal fat pad. Of particular interest is the high reparative potential of the buccal fat pad, which may be contributed to by the presence of mesenchymal stem cells. The purpose of this work is to evaluate the reparative potential of BFP cells using morphological and immunohistochemical examination. Materials and Methods: 30 BFP samples were provided by the Clinic of Maxillofacial and Plastic Surgery of the Russian University of Medicine (Moscow, Russia) from 28 patients. Morphological examination of 30 BFP samples was performed at the Institute of Clinical Morphology and Digital Pathology of Sechenov University. Hematoxylin–eosin, Masson trichrome staining and immunohistochemical examination were performed to detect MSCs using primary antibodies CD133, CD44 and CD10. Results: During staining with hematoxylin–eosin and Masson’s trichrome, we detected adipocytes of white adipose tissue united into lobules separated by connective tissue layers, a large number of vessels of different calibers, as well as the general capsule of BFP. The thin connective tissue layers contained neurovascular bundles. Statistical processing of the results of the IHC examination of the samples using the Mann–Whitney criterion revealed that the total number of samples in which the expression of CD44, CD10 and CD133 antigens was confirmed was statistically significantly higher than the number of samples where the expression was not detected (p < 0.05). Conclusions: During the morphological study of the BFP samples, we revealed statistically significant signs of MSCs presence (p < 0.05), including in the brown fat tissue, which proves the high reparative potential of this type of tissue and can make the BFP a choice option among other autogenous donor materials when eliminating OAC and other surgical interventions in the maxillofacial region.
- Published
- 2024
- Full Text
- View/download PDF
48. Cryostructuring of Polymeric Systems: 67 Properties and Microstructure of Poly(Vinyl Alcohol) Cryogels Formed in the Presence of Phenol or Bis-Phenols Introduced into the Aqueous Polymeric Solutions Prior to Their Freeze–Thaw Processing
- Author
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Olga Yu. Kolosova, Viktor G. Vasil’ev, Ivan A. Novikov, Elena V. Sorokina, and Vladimir I. Lozinsky
- Subjects
poly(vinyl alcohol) cryogel ,phenols ,physico-chemical properties ,drug release ,antimicrobial activity ,Organic chemistry ,QD241-441 - Abstract
Poly(vinyl alcohol) (PVA) physical cryogels that contained the additives of o-, m-, and p-bis-phenols or phenol were prepared, and their physico-chemical characteristics and macroporous morphology and the solute release dynamics were evaluated. These phenolic additives caused changes in the viscosity of initial PVA solutions before their freeze–thaw processing and facilitated the growth in the rigidity of the resultant cryogels, while their heat endurance decreased. The magnitude of the effects depended on the interposition of phenolic hydroxyls in the molecules of the used additives and was stipulated by their H-bonding with PVA OH-groups. Subsequent rinsing of such “primary” cryogels with pure water led to the lowering of their rigidity. The average size of macropores inside these heterophase gels also depended on the additive type. It was found also that the release of phenolic substances from the additive-containing cryogels occurred via virtually a free diffusion mechanism; therefore, drug delivery systems such as PVA cryogels loaded with either pyrocatechol, resorcinol, hydroquinone, or phenol, upon the in vitro agar diffusion tests, exhibited antibacterial activity typical of these phenols. The promising biomedical potential of the studied nanocomposite gel materials is supposed.
- Published
- 2024
- Full Text
- View/download PDF
49. Polytrauma Caused by a Bear Attacking a Human with a Benign Outcome
- Author
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Ruslan Mellin, Ellina Velichko, Larisa Maltseva, Sergey Dydykin, and Yuriy Vasil’ev
- Subjects
bear attack ,polytrauma ,maxillofacial deformities ,maxillofacial trauma ,maxillofacial reconstruction surgery ,Medicine - Abstract
Injuries to humans caused by wild animals, particularly bears, are rarely mentioned in the literature. Such injuries are frequent in Siberia, which is a territory surrounded by dense forests inhabited by brown bears. In the last 4 months alone (September–December 2023), four bear attacks on humans were registered in Khakassia, Russia. This article presents a clinical case of rehabilitating a patient after a bear attack, who suffered multiple fragmentary fractures of the facial skeleton with displaced bone fragments, subcutaneous emphysema of the soft tissues of the face, damage to the parietal and right occipital regions and paranasal sinus hemorrhage on the left side. The nature of the injuries was enhanced by trauma to the upper extremity caused by the patient defending himself against the animal. In addition to the damage to his face, the bear tried to open his cranium, as evidenced by four furrows caused by its canines, including two each on the frontal and occipital bones of the skull. The patient’s complex treatment included both maxillofacial and reconstructive surgeries, and outpatient treatment involved the formation of normotrophic scars using a neodymium laser and injections of a heterogeneous composition consisting of microparticles of “crosslinked” collagen of animal origin placed in a gel identical to the natural extracellular matrix.
- Published
- 2024
- Full Text
- View/download PDF
50. The exact solution for the free induction decay in a quasi-one-dimensional system in a multi-pulse NMR experiment
- Author
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Bochkin, G. A., Fel'dman, E. B., and Vasil'ev, S. G.
- Subjects
Quantum Physics ,Condensed Matter - Other Condensed Matter - Abstract
The exact solution for the free induction decay in a one-dimensional system in the multi-pulse experiment is obtained at both high and low temperatures in the approximation of nearest neighbor interactions. The experimental investigation is performed on a quasi-one-dimensional system of $^{19}$F nuclear spins in a single crystal of fluorapatite. The theoretical results are in a good agreement with the obtained experimental data.
- Published
- 2019
- Full Text
- View/download PDF
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