Publications by authors named "N Shevchenko"

236 Publications

Relationship between the structure of a highly regular fucoidan from Fucus evanescens and its ability to form nanoparticles.

Int J Biol Macromol 2021 Jul 1;185:679-687. Epub 2021 Jul 1.

G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch of the Russian Academy of Sciences, 690022,159,100 Let Vladivostoku prosp., Vladivostok, Russian Federation.

Chitosan/fucoidan nanoparticles were created using two fucoidans from the Fucus evanescens algae. One of them was a regular fucoidan obtained for the first time from the alga harvested at the reproductive growth stage, using only standard extraction methods, without additional modifications. Its structure was established via NMR spectroscopy to consist of the repeating →3)-α-L-Fucp-(2,4SO)-(1 → 4)-α-L-Fucp-(2SO)-(1→ fragment. Such fragment also coustituted 55% of the other fucoidan's structure, however it also included long sequences of α-L-fucopyranose residues sulfated only at C2. The nanoparticles were re-dispersed in water and the influence of fucoidan/chitosan mass ratio on the nanoparticles' size and zeta potential was investigated. 3D models of the regular fucoidan and chitosan's sections were created and their molecular docking was performed, showing that either polymer could occupy the exterior of the complex, depending on their ratio. Thermodynamic parameters of fucoidan-chitosan binding process were accessed, with the results indicating that significant conformational changes of fucoidan and chitosan molecules take place during the interaction, presumably to allow for more effective binding.
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http://dx.doi.org/10.1016/j.ijbiomac.2021.06.180DOI Listing
July 2021

Distribution of epi-endogeic and endogeic earthworm species (Oligochaeta: Lumbricidae) in the forest belt of the Northwest Caucasus.

Zootaxa 2021 May 26;4975(3):561573. Epub 2021 May 26.

Center for Forest Ecology and Productivity Russian Academy of Sciences, Moscow, 117997, Russiа..

The distribution of the often dominant in density and biomass epi-endogeic and endogeic earthworm species in forests of the Northwest Caucasus was estimated based on a large array of field data and GIS modeling of modern potential areas. Quantitative accountings of earthworms were conducted annually from 2014 to 2019 in different types of forests: sticky alder forest, small-leaved forests, broadleaf forests (hornbeam and beech forests), coniferous-deciduous forests, dark coniferous forests, and pine forests (792 geographic locations). It is shown that the native species of the Caucasian fauna dominate in the number and biomass from piedmont to high mountain forests. The most widespread species that is found in all types of forests from low to high mountains and makes the main contribution to the biomass of earthworms is the Crimean-Caucasian subendemic Dendrobaena schmidti. Peregrine species of epi-endogeic and endogeic earthworms inhabit sticky alder forest, small-leaved, broadleaf and pine forests in which they inhabit together with native species, while not dominating either in numbers or in biomass among other species. Dark coniferous forests are inhabited mainly by the native endogeic species D. schmidti and A. jassyensis. Maxent modeling shows that the species of the endogeic earthworm group have wider potential areas than epi-endogeic species. The most significant bioclimatic factors that make the greatest contribution to the distribution: amount of precipitation in the driest month, altitude above the sea level, isothermality.
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http://dx.doi.org/10.11646/zootaxa.4975.3.6DOI Listing
May 2021

Information rates in Kerr nonlinearity limited optical fiber communication systems.

Opt Express 2021 May;29(11):17428-17439

Achievable information rates of optical communication systems are inherently limited by nonlinear distortions due to the Kerr effect occurred in optical fibres. These nonlinear impairments become more significant for communication systems with larger transmission bandwidths, closer channel spacing and higher-order modulation formats. In this paper, the efficacy of nonlinearity compensation techniques, including both digital back-propagation and optical phase conjugation, for enhancing achievable information rates in lumped EDFA- and distributed Raman-amplified fully-loaded C -band systems is investigated considering practical transceiver limitations. The performance of multiple modulation formats, such as dual-polarisation quadrature phase shift keying (DP-QPSK), dual-polarisation 16 -ary quadrature amplitude modulation (DP-16QAM), DP-64QAM and DP-256QAM, has been studied in C -band systems with different transmission distances. It is found that the capabilities of both nonlinearity compensation techniques for enhancing achievable information rates strongly depend on signal modulation formats as well as target transmission distances.
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http://dx.doi.org/10.1364/OE.415753DOI Listing
May 2021

The structure of fucoidan from Sargassum oligocystum and radiosensitizing activity of galactofucans from some algae of genus Sargassum.

Int J Biol Macromol 2021 Jul 21;183:1427-1435. Epub 2021 May 21.

G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch of the Russian Academy of Sciences, 159, prosp. 100 Let Vladivostoku, 690022 Vladivostok, Russian Federation.

The aim of this study was to establish the fine structure of fucoidan from Sargassum oligocystum and to study the radiosensitizing effect of fucoidans from three algae of genus Sargassum (S. oligocystum, S. duplicatum, and S. feldmannii) with different structures. The fucoidan SoF2 from S. oligocystum was sulfated (32%) galactofucan (Fuc:Gal = 2:1), with a Mw of 183 kDa (Mw/Mn = 2.0). Its supposed structure was found to be predominantly 1,3-linked fucose as the main chain, with branching points at C2 and C4. The branches could be single galactose and/or fucose short chains with terminal galactose residues. Sulfate groups were found at positions C3, C2, and/or C4 of fucose residues and at C2 and/or C4 of galactose residues. The radiosensitizing effect of galactofucans from S. oligocystum, S. duplicatum, and S. feldmannii against human melanoma SK-MEL-28, colon HT-29, and breast MDA-MB-231 cancer cells was investigated. The influence of all investigated polysaccharides treatments with/without X-ray radiation on colony formation of human melanoma cells SK-MEL-28 was weak. Fucoidan from S. feldmannii has been shown to be the most promising radiosensitizing compound against human colon HT-29 and breast MDA-MB-231 cancer cells.
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http://dx.doi.org/10.1016/j.ijbiomac.2021.05.128DOI Listing
July 2021

COMORBIDITY OF TYPE 1 DIABETES MELLITUS WITH OTHER CHRONIC PATHOLOGY IN CHILDREN.

Georgian Med News 2021 Mar(312):78-82

1V. Karazin Kharkiv National University, School of Medicine; 2SI "Institute of Health of Children and Adolescents of the National Academy of Medical Sciences of Ukraine", Kharkiv, Ukraine.

In this study was to investigate the сoexistence of diabetes mellitus type 1 with other chronic pathology in children and adolescents and their impact on the course of diabetes mellitus type 1 (DM1). The 88 children from 3 to 17 years who had DM1 were observed. The study was conducted by survey with the aim of finding risk factors and associated comorbidties with a questionnaire-based, objective-subjective study. All patients had severe form of T1DM, with suboptimal and poor glycemic control. Comorbid pathologies observed in 71,6±4,8% of childrn included: thyroid pathology - 62,5±5,1%, disorders of the autonomic nervous system - 20,5±4,3%, gastro-pathology - 7,9±2,8%, atopic dermatitis - 6,8±2,6%, arthritis - 6,8±2,6%, bronchial asthma - 4,5±2,2%, allergic rhinitis - 3,4±1,9%, immune-deficient disorder - 2,3±1,5%. Conclusions. 1. The detected comorbid pathology in children with DM1 makes it necessary to collect an anamnesis and examination of children for the purpose of early finding a coexistence of chronic pathology. 2. The risk of development of the thyroid pathology enhances is 7,5 times, allergic pathology is 6,9 times in patients with DM1. 3. Coexistence of type 1 diabetes and other chronic diseases impairs glucose metabolism, impedes effective insulin therapy, and deteriorates diabetes control. 4. This accent the need for the improvement of the monitoring of patient with diabetes mellitus and comorbid pathology for the prognosis of the course and optimization of treatment and rehabilitation measures.
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March 2021
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