Pub Date : 2021-02-25DOI: 10.29235/1561-8323-2021-65-1-103-110
A. Ilyushchanka, T. Talako, A. Leshok, A. Letsko, T. Pinchuk
The article presents the results of study of the effect of additives of an ultrafine powder of the Ti–46Al–8Cr system obtained by MASHS on the tribotechnical properties of a friction material based on BrO6 bronze. It is shown that in the range of powder additive concentrations 0.5–1.5 wt. %, the dynamic coefficient of friction increases from 0.04 to 0.055, in the range of 1.5–2.5 % – to 0.055–0.058. The introduction of the 0.5–1.0 % Ti–46Al–8Cr powder permitted to reduce the wear rate of the friction material from 4.0 to 3.7 μm/km. An increase in the additive to 2.5 % led to an increase in the material wear rate up to 6 μm/km.
{"title":"Tribotechnical properties of sintered friction material based on copper with the additives of the ultrafine powder of aluminide of Ti–46Al–8Cr system","authors":"A. Ilyushchanka, T. Talako, A. Leshok, A. Letsko, T. Pinchuk","doi":"10.29235/1561-8323-2021-65-1-103-110","DOIUrl":"https://doi.org/10.29235/1561-8323-2021-65-1-103-110","url":null,"abstract":"The article presents the results of study of the effect of additives of an ultrafine powder of the Ti–46Al–8Cr system obtained by MASHS on the tribotechnical properties of a friction material based on BrO6 bronze. It is shown that in the range of powder additive concentrations 0.5–1.5 wt. %, the dynamic coefficient of friction increases from 0.04 to 0.055, in the range of 1.5–2.5 % – to 0.055–0.058. The introduction of the 0.5–1.0 % Ti–46Al–8Cr powder permitted to reduce the wear rate of the friction material from 4.0 to 3.7 μm/km. An increase in the additive to 2.5 % led to an increase in the material wear rate up to 6 μm/km.","PeriodicalId":11283,"journal":{"name":"Doklady of the National Academy of Sciences of Belarus","volume":"54 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84510488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-02-25DOI: 10.29235/1561-8323-2021-65-1-33-39
V. Kudryashov, Á. Baran
The circular quantum dots localized in the double heterostructures are simulated by means of the axially symmetric smooth confinement potential of finite depth. For the proposed potential of new type, the exact wave functions and the energy levels of electron are found. The dependence of energy spectrum on potential parameters is investigated.
{"title":"Modeling of circular quantum dots localized in double heterostructures","authors":"V. Kudryashov, Á. Baran","doi":"10.29235/1561-8323-2021-65-1-33-39","DOIUrl":"https://doi.org/10.29235/1561-8323-2021-65-1-33-39","url":null,"abstract":"The circular quantum dots localized in the double heterostructures are simulated by means of the axially symmetric smooth confinement potential of finite depth. For the proposed potential of new type, the exact wave functions and the energy levels of electron are found. The dependence of energy spectrum on potential parameters is investigated.","PeriodicalId":11283,"journal":{"name":"Doklady of the National Academy of Sciences of Belarus","volume":"49 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74937641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-02-25DOI: 10.29235/1561-8323-2021-65-1-18-24
A. Astrovskii
In terms of matrix observability, the necessary and sufficient conditions are obtained for the linear timevarying observation system to have stationary orbits with respect to the linear time-varying transformation group of class C1 . The full invariant of the action of a transformation group is described. It is proved that for any matrix function A c C(T, Rn×n ), there exists such an n-vector function c(t), t c T, that the pair (A, c) is uniformly observable. The algorithm for constructing a stationary system is described.
在矩阵可观测性方面，得到了线性时变观测系统相对于C1类线性时变变换群具有平稳轨道的充分必要条件。描述了变换群作用的完全不变量。证明了对于任意矩阵函数A c c(T, Rn×n)，存在这样一个n向量函数c(T)， T c T，使得(A, c)对是一致可观察的。描述了构造平稳系统的算法。
{"title":"Stationary orbits of linear time-varying observation systems","authors":"A. Astrovskii","doi":"10.29235/1561-8323-2021-65-1-18-24","DOIUrl":"https://doi.org/10.29235/1561-8323-2021-65-1-18-24","url":null,"abstract":"In terms of matrix observability, the necessary and sufficient conditions are obtained for the linear timevarying observation system to have stationary orbits with respect to the linear time-varying transformation group of class C1 . The full invariant of the action of a transformation group is described. It is proved that for any matrix function A c C(T, Rn×n ), there exists such an n-vector function c(t), t c T, that the pair (A, c) is uniformly observable. The algorithm for constructing a stationary system is described.","PeriodicalId":11283,"journal":{"name":"Doklady of the National Academy of Sciences of Belarus","volume":"42 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89081209","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-02-25DOI: 10.29235/1561-8323-2021-65-1-25-32
P. Matus, H. Anh
In this paper, we consider the compact difference approximation of the fourth and second-order schemes on a three-point stencil for Klein–Gordon equations with variable coefficients. Despite the linearity of the differential and difference problems, it is not possible in this case to apply the well-known results on the theory of stability of three-layer operator-difference schemes by A. A. Samarskii. The main purpose is to prove the stability with respect to the initial data and the right-hand side of compact difference schemes in the grid norms L 2 (W h ), W 1 2 (W h ), C (W h ). Using the method of energy inequalities, the corresponding a priori estimates, expressing the stability and convergence of the solution to the difference problem with the assumption h ≤ = h 0, h 0 = const, τ≥h is obtained. The conducted numerical experiment shows how Runge rule is used to determine the different orders of the convergence rate of the difference scheme in the case of two independent variables.
{"title":"Compact difference schemes for Klein–Gordon equation with variable coefficients","authors":"P. Matus, H. Anh","doi":"10.29235/1561-8323-2021-65-1-25-32","DOIUrl":"https://doi.org/10.29235/1561-8323-2021-65-1-25-32","url":null,"abstract":"In this paper, we consider the compact difference approximation of the fourth and second-order schemes on a three-point stencil for Klein–Gordon equations with variable coefficients. Despite the linearity of the differential and difference problems, it is not possible in this case to apply the well-known results on the theory of stability of three-layer operator-difference schemes by A. A. Samarskii. The main purpose is to prove the stability with respect to the initial data and the right-hand side of compact difference schemes in the grid norms L 2 (W h ), W 1 2 (W h ), C (W h ). Using the method of energy inequalities, the corresponding a priori estimates, expressing the stability and convergence of the solution to the difference problem with the assumption h ≤ = h 0, h 0 = const, τ≥h is obtained. The conducted numerical experiment shows how Runge rule is used to determine the different orders of the convergence rate of the difference scheme in the case of two independent variables.","PeriodicalId":11283,"journal":{"name":"Doklady of the National Academy of Sciences of Belarus","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90378768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-02-25DOI: 10.29235/1561-8323-2021-65-1-111-118
V. Pilipenko, J. Solovjov, P. Gaiduk
The formation of nickel silicide layers on (111)-Si substrates during rapid thermal annealing in the heat balance mode was studied by the Rutherford backscattering method, X-ray diffraction, transmission electron microscopy, and electrophysical measurements. Nickel films of about 70 nm thickness were deposited by magnetron sputtering at room temperature. The rapid thermal treatment was carried out in a heat balance mode by irradiating the substrates backside with a non-coherent light flux of quartz halogen lamps in the nitrogen medium for 7 seconds up to the temperature range of 200 to 550 °C. The redistribution of nickel and silicon atoms to monosilicide NiSi composition starts already at a temperature of 300 °С and almost ends at a temperature of 400 °С. In the same temperature range, the orthorhombic NiSi phase with an average grain size of about 0.05–0.1 μm is formed. At a rapid thermal treatment temperature of 300 °C, two phases of silicides (Ni2 Si and NiSi) are formed, while a thin layer of unreacted Ni is retained on the surface. This fact can be explained by the high heating rate at the initial annealing stage, at which the temperature conditions of the NiSi phase formation occur earlier than the entire Ni layer manages to turn into the Ni2 Si phase. The layers with a simultaneous presence of three phases are characterized by a high roughness of the silicide-silicon interface. The dependence of the specific resistivity of nickel silicide layers shows an increase to the values of 26–30 μOhm · cm in the range of rapid thermal treatment temperatures of 200–250 °C and a subsequent decrease to the values of about 15 μOhm · cm at a rapid thermal treatment temperature of 400 °C. This value of specific resistivity is characteristic of the high conductivity of the NiSi phase and correlates well with the results of structure studies.
{"title":"Nickel silicide formation with rapid thermal treatment in the heat balance mode","authors":"V. Pilipenko, J. Solovjov, P. Gaiduk","doi":"10.29235/1561-8323-2021-65-1-111-118","DOIUrl":"https://doi.org/10.29235/1561-8323-2021-65-1-111-118","url":null,"abstract":"The formation of nickel silicide layers on (111)-Si substrates during rapid thermal annealing in the heat balance mode was studied by the Rutherford backscattering method, X-ray diffraction, transmission electron microscopy, and electrophysical measurements. Nickel films of about 70 nm thickness were deposited by magnetron sputtering at room temperature. The rapid thermal treatment was carried out in a heat balance mode by irradiating the substrates backside with a non-coherent light flux of quartz halogen lamps in the nitrogen medium for 7 seconds up to the temperature range of 200 to 550 °C. The redistribution of nickel and silicon atoms to monosilicide NiSi composition starts already at a temperature of 300 °С and almost ends at a temperature of 400 °С. In the same temperature range, the orthorhombic NiSi phase with an average grain size of about 0.05–0.1 μm is formed. At a rapid thermal treatment temperature of 300 °C, two phases of silicides (Ni2 Si and NiSi) are formed, while a thin layer of unreacted Ni is retained on the surface. This fact can be explained by the high heating rate at the initial annealing stage, at which the temperature conditions of the NiSi phase formation occur earlier than the entire Ni layer manages to turn into the Ni2 Si phase. The layers with a simultaneous presence of three phases are characterized by a high roughness of the silicide-silicon interface. The dependence of the specific resistivity of nickel silicide layers shows an increase to the values of 26–30 μOhm · cm in the range of rapid thermal treatment temperatures of 200–250 °C and a subsequent decrease to the values of about 15 μOhm · cm at a rapid thermal treatment temperature of 400 °C. This value of specific resistivity is characteristic of the high conductivity of the NiSi phase and correlates well with the results of structure studies.","PeriodicalId":11283,"journal":{"name":"Doklady of the National Academy of Sciences of Belarus","volume":"87 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89881812","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-02-25DOI: 10.29235/1561-8323-2021-65-1-11-17
N. Y. Kazlouskaya, Y. A. Rovba
In the present article, the approximation of the function |sin x| s by the partial sums of the rational trigonometric Fourier series is considered. An integral representation, uniform and point estimates for the above-mentioned approximation were obtained. Based on them, several special cases of the selection of poles were studied. In the case of the approximation by the partial sums of the polynomial trigonometric Fourier series, an asymptotic equality was found. A detailed study is made of a fixed number of geometrically different poles.
{"title":"Approximation of the function |sin x| s by the partial sums of the trigonmometric rational fourier series","authors":"N. Y. Kazlouskaya, Y. A. Rovba","doi":"10.29235/1561-8323-2021-65-1-11-17","DOIUrl":"https://doi.org/10.29235/1561-8323-2021-65-1-11-17","url":null,"abstract":"In the present article, the approximation of the function |sin x| s by the partial sums of the rational trigonometric Fourier series is considered. An integral representation, uniform and point estimates for the above-mentioned approximation were obtained. Based on them, several special cases of the selection of poles were studied. In the case of the approximation by the partial sums of the polynomial trigonometric Fourier series, an asymptotic equality was found. A detailed study is made of a fixed number of geometrically different poles.","PeriodicalId":11283,"journal":{"name":"Doklady of the National Academy of Sciences of Belarus","volume":"179 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89270847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-31DOI: 10.29235/1561-8323-2020-64-6-757-768
I. Sheyko, T. N. Timoshenko, N. V. Pristupa, E. Yanovich, V. N. Zayats, R. Sheyko, I. N. Kazarovets, A. Burnos, I. Kosko
Six pig breeds: Belarusian large white, Belarusian meat, Belarusian black and white, landrace, Yorkshire and Duroc are involved in breeding and hydridization of pig breeding in Belarus. More than 85 % of pigs supplied to meat processing plants of the Republic are provided by different combinations of interbreed hydridization.For the effective development of this branch in the Republic, the Scientific-Practical Center on Animal Husbandry of the National Academy of Sciences of Belarus organized the system of selection and breeding work in pig breeding directed to create new competitive breeds, types, and hydrides of pigs adapted to the industrial production conditions and not inferior to the productivity of the analogs of the world selection.The main link of this system is the first-order breeding plants (nucleus units) as new-type plants dealing with the selection and breeding of the best animals with the outstanding genetically conditioned breeding and productive qualities. The second link of this system is the first-order breeding breeders that are completed with high-valuable breeding pigs from the leading nucleus unit and are engaged in their reproduction to obtain grandparents (GP).Assessing the level of the technological development of pig breeding in Belarus during the period to the 2030 year, we predicted the indices for the all predictable years (2020–2030). The existing level of the technological development of the pig breeding branch is assessed as the mean one. During 2020–2021 the pig breeding level will be moderate-high, during 2022– 2023 – high, and since 2025–2030 – intensive.
{"title":"New breeding and genetic methods in pig breeding in Belarus","authors":"I. Sheyko, T. N. Timoshenko, N. V. Pristupa, E. Yanovich, V. N. Zayats, R. Sheyko, I. N. Kazarovets, A. Burnos, I. Kosko","doi":"10.29235/1561-8323-2020-64-6-757-768","DOIUrl":"https://doi.org/10.29235/1561-8323-2020-64-6-757-768","url":null,"abstract":"Six pig breeds: Belarusian large white, Belarusian meat, Belarusian black and white, landrace, Yorkshire and Duroc are involved in breeding and hydridization of pig breeding in Belarus. More than 85 % of pigs supplied to meat processing plants of the Republic are provided by different combinations of interbreed hydridization.For the effective development of this branch in the Republic, the Scientific-Practical Center on Animal Husbandry of the National Academy of Sciences of Belarus organized the system of selection and breeding work in pig breeding directed to create new competitive breeds, types, and hydrides of pigs adapted to the industrial production conditions and not inferior to the productivity of the analogs of the world selection.The main link of this system is the first-order breeding plants (nucleus units) as new-type plants dealing with the selection and breeding of the best animals with the outstanding genetically conditioned breeding and productive qualities. The second link of this system is the first-order breeding breeders that are completed with high-valuable breeding pigs from the leading nucleus unit and are engaged in their reproduction to obtain grandparents (GP).Assessing the level of the technological development of pig breeding in Belarus during the period to the 2030 year, we predicted the indices for the all predictable years (2020–2030). The existing level of the technological development of the pig breeding branch is assessed as the mean one. During 2020–2021 the pig breeding level will be moderate-high, during 2022– 2023 – high, and since 2025–2030 – intensive.","PeriodicalId":11283,"journal":{"name":"Doklady of the National Academy of Sciences of Belarus","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78915311","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-31DOI: 10.29235/1561-8323-2020-64-6-647-656
N. A. Likhoded, A. Tolstsikau
Locality is an algorithm characteristic describing a usage level of fast access memory. For example, in case of distributed memory computers we focus on memory of each computational node. To achieve the high performance of algorithm implementation one should choose the best possible locality option. Studying the parallel algorithm locality is to estimate the number and volume of data communications. In this work, we formulate and prove the statements for computers with distributed memory that allow us to estimate the asymptotic volume of data communication operations. These estimation results are useful while comparing alternative versions of parallel algorithms during data communication cost analysis.
{"title":"Locality estimation of parallel algorithm for distributed memory computers","authors":"N. A. Likhoded, A. Tolstsikau","doi":"10.29235/1561-8323-2020-64-6-647-656","DOIUrl":"https://doi.org/10.29235/1561-8323-2020-64-6-647-656","url":null,"abstract":"Locality is an algorithm characteristic describing a usage level of fast access memory. For example, in case of distributed memory computers we focus on memory of each computational node. To achieve the high performance of algorithm implementation one should choose the best possible locality option. Studying the parallel algorithm locality is to estimate the number and volume of data communications. In this work, we formulate and prove the statements for computers with distributed memory that allow us to estimate the asymptotic volume of data communication operations. These estimation results are useful while comparing alternative versions of parallel algorithms during data communication cost analysis.","PeriodicalId":11283,"journal":{"name":"Doklady of the National Academy of Sciences of Belarus","volume":"30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89982277","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-31DOI: 10.29235/1561-8323-2020-64-6-739-746
M. Kheifetz
The analysis of the stages and stages of the design of technological equipment for traditional production, studied the features of the formation of technological equipment using flows of energy and consumables. Structural synthesis of mechatronic complexes in digitalized production allowed adding new stages to the process of creating technological equipment for both traditional automated subtractive and new additive manufacturing. The processes of manufacturing parts without shaping equipment described by the algorithms according to the proposed structural diagram of connections provide an opportunity to analyze existing and develop new equipment in laminate synthesis of products. It is shown, how in the design of technological equipments for their use in new additive and traditional subtractive manufacturing, methods and schemes of laminate synthesis and shaping of parts from composite materials are used, based on the use of various energy flows and material components, as well as methods and schemes of automation and computer product manufacturing process management.
{"title":"Design of mechatronic technological complexes for traditional and additive manufacturing","authors":"M. Kheifetz","doi":"10.29235/1561-8323-2020-64-6-739-746","DOIUrl":"https://doi.org/10.29235/1561-8323-2020-64-6-739-746","url":null,"abstract":"The analysis of the stages and stages of the design of technological equipment for traditional production, studied the features of the formation of technological equipment using flows of energy and consumables. Structural synthesis of mechatronic complexes in digitalized production allowed adding new stages to the process of creating technological equipment for both traditional automated subtractive and new additive manufacturing. The processes of manufacturing parts without shaping equipment described by the algorithms according to the proposed structural diagram of connections provide an opportunity to analyze existing and develop new equipment in laminate synthesis of products. It is shown, how in the design of technological equipments for their use in new additive and traditional subtractive manufacturing, methods and schemes of laminate synthesis and shaping of parts from composite materials are used, based on the use of various energy flows and material components, as well as methods and schemes of automation and computer product manufacturing process management.","PeriodicalId":11283,"journal":{"name":"Doklady of the National Academy of Sciences of Belarus","volume":"7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84791404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-31DOI: 10.29235/1561-8323-2020-64-6-723-729
A. Rudenko, T. Tyabut, A. Buglova, G. Babak, P. M. Morozik, T. D. Borisenko
Vitamin D deficiency is an important environmental risk factor that influences the prevalence and severity of several autoimmune diseases, including rheumatoid arthritis (RA). The aim of this study was to determine the incidence of vitamin D insufficiency and deficiency in patients with RA, to establish the relationship between serum vitamin D levels and indicators of disease activity. 156 patients with RA were included in the study, mean age 60.2 ± 13.9 years. Assessment of clinical status was performed, serum concentrations of rheumatoid factor (RF), C-reactive protein (CRP), total vitamin D (25(OH)D), antibodies to cyclic citrullinated peptide (ACCP) were determined. RA disease activity was evaluated using DAS28 (disease activity score), SDAI (Simplified Disease Activity Index) и CDAI (Clinical Disease Activity Index) scores. Average levels of 25(OH)D in the surveyed sample were 25.2 ± 13.2 ng/ml. The results of the study indicate a high prevalence of vitamin D deficiency in patients with RA. Normal indicators of vitamin D, its insufficiency and deficiency were observed in 47 (30.3 %), 45 (28.7 %) and 64 (40.7 %) patients, respectively. Low level of serum 25(OH)D was associated with higher indices of RA activity according to DAS28, SDAI and CDAI, as well as with greater tender joint count. Vitamin D should be prescribed as an adjunctive therapy in patients with active RA due to its potential immunomodulatory effect, as well as for the prevention and treatment of bone metabolism disorders.
{"title":"Rate of hypovitaminosis D and association of plasma concentration of 25(OH)D with indicators of disease activity in patients with rheumatoid arthritis","authors":"A. Rudenko, T. Tyabut, A. Buglova, G. Babak, P. M. Morozik, T. D. Borisenko","doi":"10.29235/1561-8323-2020-64-6-723-729","DOIUrl":"https://doi.org/10.29235/1561-8323-2020-64-6-723-729","url":null,"abstract":"Vitamin D deficiency is an important environmental risk factor that influences the prevalence and severity of several autoimmune diseases, including rheumatoid arthritis (RA). The aim of this study was to determine the incidence of vitamin D insufficiency and deficiency in patients with RA, to establish the relationship between serum vitamin D levels and indicators of disease activity. 156 patients with RA were included in the study, mean age 60.2 ± 13.9 years. Assessment of clinical status was performed, serum concentrations of rheumatoid factor (RF), C-reactive protein (CRP), total vitamin D (25(OH)D), antibodies to cyclic citrullinated peptide (ACCP) were determined. RA disease activity was evaluated using DAS28 (disease activity score), SDAI (Simplified Disease Activity Index) и CDAI (Clinical Disease Activity Index) scores. Average levels of 25(OH)D in the surveyed sample were 25.2 ± 13.2 ng/ml. The results of the study indicate a high prevalence of vitamin D deficiency in patients with RA. Normal indicators of vitamin D, its insufficiency and deficiency were observed in 47 (30.3 %), 45 (28.7 %) and 64 (40.7 %) patients, respectively. Low level of serum 25(OH)D was associated with higher indices of RA activity according to DAS28, SDAI and CDAI, as well as with greater tender joint count. Vitamin D should be prescribed as an adjunctive therapy in patients with active RA due to its potential immunomodulatory effect, as well as for the prevention and treatment of bone metabolism disorders.","PeriodicalId":11283,"journal":{"name":"Doklady of the National Academy of Sciences of Belarus","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73032172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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