Papers by Pavel Maslennikov
Chemical Physics Letters, May 1, 2018
We have considered a homogeneously aligned liquid crystal ͑HALC͒ microvolume confined between two... more We have considered a homogeneously aligned liquid crystal ͑HALC͒ microvolume confined between two infinitely long horizontal coaxial cylinders and investigated dynamic field pumping, i.e., studied the interactions between director, velocity, and electric E fields as well as a radially applied temperature gradient ٌT, where the inner cylinder is kept at a lower temperature than the outer one. In order to elucidate the role of ٌT in producing hydrodynamic flow u, we have carried out a numerical study of a system of hydrodynamic equations including director reorientation, fluid flow, and temperature redistribution across the HALC cavity. Calculations show that only under the influence of ٌT does the initially quiescent HALC sample settle down to a stationary flow regime with horizontal component of velocity u eq ͑r͒. The effects of ٌT and of the size of the HALC cavity on magnitude and direction of u eq ͑r͒ have been investigated for a number of hydrodynamic regimes. Calculations also showed that E influences only the director redistribution across the HALC but not the magnitude of the velocity u eq ͑r͒.
Agronomy research, 2018
In this paper, we investigate changes in the antioxidant levels (anthocyanins, leucoanthocyanins,... more In this paper, we investigate changes in the antioxidant levels (anthocyanins, leucoanthocyanins, catechins) and the total water-soluble antioxidants capacity in forage plants in relation to their geography, i.e. proximity to northern or coastal areas. We demonstrate that the antioxidant content increases in unfavorable conditions, being higher in plants growing closer to the sea and in northernmost plants. Thus, since the total water-soluble antioxidants capacity is influenced by ecological factors, it may be used as one of the indicators in complex environmental assessment.
Вестник Балтийского федерального университета им. И. Канта. Серия: Естественные и медицинские науки, 2006
EGU General Assembly Conference Abstracts, Apr 1, 2019
Physical review, Aug 26, 2021
The aim of this paper is to investigate the response of a homogeneously aligned nematic nanosized... more The aim of this paper is to investigate the response of a homogeneously aligned nematic nanosized hollow cavity (HANNHC) confined between two charged horizontal coaxial cylinders and subjected to both a radially applied electrostatic field E, arising from the surface charge density κ and the temperature gradient ∇T set between these cylinders. This was done within the framework of an extension of the classical Ericksen-Leslie theory, supplemented by thermomechanical correction of the shear stress and Rayleigh dissipation function, as well as taking into account the entropy balance equation. The physical mechanism responsible for the excitation of the hydrodynamic flow in the HANNHC is based on the interaction of the director and temperature gradients and the static electric field. Calculations show that under the influence of both the ∇T and E, a stationary flow u st is excited in the HANNHC in the horizontal direction. It is shown that the electric force enforced by the flexoelectric polarization plays a crucial role in the excitation of u st between these cylinders.
Physical review, Jan 13, 2021
An electrically driven fluid pumping principle and a mechanism of kinklike distortion of the dire... more An electrically driven fluid pumping principle and a mechanism of kinklike distortion of the director fieldn in the microsized nematic volume has been described. It is shown that the interactions, on the one hand, between the electric field E and the gradient of the director's field ∇n, and, on the other hand, between the ∇n and the temperature gradient ∇T arising in a homogeneously aligned liquid crystal microfluidic channel, confined between two infinitely long horizontal coaxial cylinders, may excite the kinklike distortion wave spreading along normal to both cylindrical boundaries. Calculations show that the resemblance to the kinklike distortion wave depends on the value of radially applied electric field E and the curvature of these boundaries. Calculations also show that there exists a range of parameter values (voltage and curvature of the inner cylinder) producing a nonstandard pumping regime with maximum flow near the hot cylinder in the horizontal direction.
IOP conference series, Mar 1, 2021
Various parts of guelder rose (Viburnum opulus L.), including the bark, leaves, flowers, and frui... more Various parts of guelder rose (Viburnum opulus L.), including the bark, leaves, flowers, and fruits, have long been used in modern and folk medicine. This study aims to evaluate how site climatic conditions and soil properties influence the accumulation of phenolic antioxidants in flowers and fruits of Viburnum opulus L. It was established that the content of total phenolics in fruits was 1.7 times that in the flowers; the content of tannins, 2.5 times; antioxidant activity, 2.3 times. A high correlation between antioxidant capacity and the content of phenolic compounds (r = 0.90; p <0.001) and tannins (r = 0.94; p <0.001) was revealed. Site conditions have a strong effect both on the accumulation of secondary metabolites in Viburnum opulus L. and on the antioxidant activity of the study sample extracts. The highest concentrations of the phytocomponents under study were associated with heavy precipitation and high average contents of organic matter and macroelements (phosphorus, potassium, and nitrogen). These findings highlight the importance of fulfilling agro-technical requirements for the cultivation of Viburnum opulus L., both to ensure high yields and to obtain products with better biochemical composition.
Химия растительного сырья, 2017
Современные проблемы науки и образования, 2015
Вестник Балтийского федерального университета им. И. Канта. Серия: Естественные и медицинские науки, 2010
Анализировался эндогенный уровень антиоксидантов в растениях Куршской косы. Выявлены группы расте... more Анализировался эндогенный уровень антиоксидантов в растениях Куршской косы. Выявлены группы растений с максимальным содержанием антоцианов и водорастворимых антиоксидантов в растительных тканях. Показана положительная корреляционная зависимость между содержанием антоцианов и уровнем каротиноидов, отрицательная корреляционная зависимость между содержанием антоцианов и антиоксидантная активность в листьях исследуемых растений вне зависимости от экологических условий произрастания. This article analyses the endogenous level of antioxidants in the plants growing on the Curonian spit. The authors distinguished two groups of plants with the highest content of anthocyans and the water-soluble antioxidants in plant tissues and determined a positive correlation dependency between the anthocyan content and the level of carotenoids and a negative correlation dependency between the anthocyans and АОА content in the leaves of plants under consideration regardless of environmental conditions.
IOP conference series, Aug 1, 2020
The authors analyse the results of mycological studies of the soil of one of the largest solid wa... more The authors analyse the results of mycological studies of the soil of one of the largest solid waste landfills in the Moscow region - the Salaryevo solid waste landfill. The agroecological and geochemical characteristics of the contaminated soil are explored. The authors studied the phytotoxicity of soil fungi, using Pisum sativum L as an object of analysis. The number of microscopic fungi in the contaminated soil increased 7 times, the phytotoxic fungi of the genus Alternaria, were 1.8 times higher than the reference level. Penicillium decreased by almost 30%. In many soil samples, fungi of the genus Fusarium were found. An increase in the number of fungi of the genus Alternaria had phytotoxic effect: in pea seedlings (Pisum sativum L.), a slower growth of roots and seedlings was observed.
Symmetry, Apr 28, 2022
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Chemical Physics Letters, 2017
The peculiarities in the dynamics of the director reorientation in confined nematic liquid crysta... more The peculiarities in the dynamics of the director reorientation in confined nematic liquid crystals (LCs) under the influence of a strong electric field E have been investigated theoretically based on the hydrodynamic theory including the director motion with appropriate boundary and initial conditions. Analysis of the numerical results for the turn-on process, when a strong electric field E is suddenly applied in the positive sense, provides an evidence for the appearance of the spatially periodic patterns in confined LC film.
Izvestiâ Timirâzevskoj selʹskohozâjstvennoj akademii, 2017
Chemical Physics Letters, 2018
The peculiarities in the dynamics of the director reorientation in confined nematic liquid crysta... more The peculiarities in the dynamics of the director reorientation in confined nematic liquid crystals (LCs) under the influence of a strong electric field E directed at an angle α to the magnetic field B have been investigated theoretically on the basis of the hydrodynamic theory including the director motion with appropriate boundary and initial conditions. Analysis of the numerical results for the turn-on process, when the strong electric field E is suddenly applied, provides an evidence for the appearance of the spatially periodic patterns in confined LC film. Calculations show that when the angle α tends to be 90 • , the optimum wavelength, giving the fastest response, provides the lower effective viscosity γ eff (α), which is less than one in the bulk nematic phase. So, a lower value of γ eff (α) gives a faster relaxation times, as observed experimentally by using the time-resolved deuterium NMR spectroscopy.
Physical Review E, 2022
A molecular model describing the effective anchoring energy of a liquid crystal (LC) system, comp... more A molecular model describing the effective anchoring energy of a liquid crystal (LC) system, composed of 4-n-pentyl-4-cyanobiphenyl (5CB) molecules deposited on a photosensitive azobenzene layer consisting of 6Az10PVA molecules, is proposed. This model takes into account the interaction between the surface polarization in the LC phase and the surface electric field, arising from the surface charge density. Within the framework of this molecular model, the mechanism responsible for the anchoring transition in the LC phase from homeotropic to planar alignment and vice versa, caused by trans-cis and cis-trans conformational changes in the monolayer 6Az10PVA after laser radiation, is described. It is shown that using experimental data for the voltage across the 6Az10PVA+5CB film, obtained by the surface potential technique, the charge separation during the conformational changing, caused by the laser irradiation, may lead to an anchoring transition induced by trans-cis-trans isomerization in the photosensitive azobenzene monolayer. The calculated values of the isothermal surface pressure diagram π-A showed that the surface area A per LC molecule is noticeably higher for the cis configuration, which reflects a less efficient packaging than in the trans state.
Symmetry
The aim of this theoretical paper is to investigate the physical mechanism responsible for the ap... more The aim of this theoretical paper is to investigate the physical mechanism responsible for the appearance of vortex flow in a hybrid aligned nematic (HAN) microvolume with an orientational defect, excited by a temperature gradient ∇T. This was done in the framework of the classical Ericksen-Leslie theory, supplemented by thermomechanical correction of the shear stress and Rayleigh dissipation function, as well as taking into account the entropy balance equation. We have carried out a numerical study of the system of hydrodynamic equations including director reorientation, fluid flow v, and the temperature redistribution across the HAN microvolume under the influence of ∇T, when the HAN microvolume is heated from above. Calculations show that, due to the interaction between the gradient of the director field ∇n^ and ∇T, the HAN microvolume settles down to a stationary complex vortex flow regime.
Horticulturae
Hyssop (Hyssopus officinalis L.) is an aromatic plant that is rich in various biologically active... more Hyssop (Hyssopus officinalis L.) is an aromatic plant that is rich in various biologically active compounds and is widely used as a natural preservative and flavoring agent in the food and cosmetic industry and as a folk medicine against certain respiratory diseases. Despite the fact that selenium is not an essential trace element for plants, in a certain range of concentrations it can not only improve plant growth, but also increase the content of nutrients and biologically active compounds in plants. In the present study, the effect of treatment type (in a nutrient solution (NS) or by foliar application (FA)) and selenium (Se) concentration (2.0, 5.0, 10.0, 20.0, 40.0 μM) on the biomass, phenolic compounds, essential oil content, and antioxidant properties of hyssop grown in hydroponics was studied. Neither a toxic nor a beneficial effect of Se addition on the plants was observed. Selenium treatment significantly increased Se concentration in hyssop up to 38.35 μg g−1 (NS) and 34....
Physical review, Nov 23, 2022
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Papers by Pavel Maslennikov