Lesya Ukrainka Eastern European National University
Recent publications
In this work, the influence of hydrostatic pressure on the structural, electronic, optical, and mechanical properties of chalcopyrite AgAlS2 crystal was investigated by the first-principles density functional theory calculations. The lattice parameters and unit cell volume decrease with the hydrostatic pressure leading to an increase in the total energy of the crystal. Shown, the bandgap value increases with the pressure while the general peculiarities of the band structure remain almost unchanged. The baric dependences of the real and imaginary parts of the dielectric function are constructed and their analysis is carried out. Several elastic parameters of the material are calculated, such as elastic coefficients Cij, modulus of elasticity B, shear modulus G, Young's modulus E, Poisson's ratio v. Calculated bulk modulus is consistent with previous theoretical study. The spatial distribution of elastic coefficients and their planar projections are constructed and it is shown that hydrostatic pressure leads to an increase in their anisotropy. It is shown that the modulus of elasticity B has the smallest anisotropy, while the largest is observed for the shear modulus G.
This work studies the problem of thermomagnetoelectroelastic anisotropic bimaterial with imperfect high-temperature conducting coherent interface, whose components contain thin inclusions. Using the extended Stroh formalism and complex variable calculus, the Somigliana-type integral formulae and the corresponding boundary integral equations for the anisotropic thermomagnetoelectroelastic bimaterial with high-temperature conducting coherent interface are obtained. These integral equations are introduced into the modified boundary element approach. The numerical analysis of new problems is held and results are presented for single and multiple inclusions.
The paper presents a novel approach for analysis of thermoelasticity problems for solids with deformable thread-like (wired, textile) inhomogeneities. It is proposed to model a thread-like inclusion with a spatial curve, with appropriate influence functions set on it. The mathematical models of heat conduction and thermoelasticity of thread-like inclusions are obtained, which account for thermal, elastic and thermoelastic properties of these inhomogeneities. Combined with the boundary integral equations for a medium with a thread-like inhomogeneity these models allow obtaining equations for determination of sought influence functions. Their solution technique is proposed based on the orthogonal polynomials approach. The methods for determination of thermoelastic property contribution tensors are considered, which allows determination of effective properties of fiber reinforced composite materials and has wide applications in modern material engineering. Corresponding numerical examples are presented and verified.
A 3-phenylpropanal and citral were studied in the multicomponent reaction with the isorhodanine and maleimides (EDDA catalyst) with the aim of the novel thiopyrano[2,3-d]thiazoles synthesis. 3-Phenylpropanal reacts with the selective formation of the thiopyrano[2,3-d]thiazoles whereas citral led to the mixture of two products and Michael adducts are major. The one-pot/two-steps protocol was proposed for citral transformation to the target thiopyrano[2,3-d]thiazoles. The structures and stereochemistry of newly synthesized compounds were studied by spectral and X-ray data.
Development of cancer drug-resistance is still an ongoing problem in the modern anticancer treatment. Therefore, there is a need to search for a new active substance, which may become a potential anticancer agent. 4-Thiazolidinones are well-described substances with cytotoxicity against cancer cells in vitro. Therefore, the aim of this study was to evaluate the effect of two 4-thiazolidinone-based derivatives (Les-2769 and Les-3266) on the PPARγ-dependent cytotoxicity in normal human skin fibroblasts (BJ) and squamous cell carcinoma (SCC-15) in vitro. The data obtained showed a cytotoxic effect of Les-2769 and Les-3266 used in micromolar concentrations on SCC-15 and BJ cells, manifesting by a decrease in the metabolic activity, an increase in the release of lactate dehydrogenase, and caspase-3 activity. The co-treatment of the cells with Les-3266 and an antagonist (GW9662) or an agonist (rosiglitazone) of the PPARγ receptor induced changes in the above-mentioned parameters in the BJ and SCC-15 cells, compared to the Les-3266 alone exposure; this was not found in the Les-2769-treated cells. The further analysis of the compounds indicated changes in the expression of the PPARγ, KI67, and NF-κB genes. Moreover, the tested compounds caused an increase in the level of PPARγ mRNA expression in a similar way to rosiglitazone in SCC-15, which may indicate the affinity of the compounds for PPARγ. Molecular docking is consistent with experimental in vitro data about the potential agonistic activity of Les-2769 and Les-3266 towards PPARγ receptors. Summarizing, the anticancer effect of both compounds was observed in the SCC-15 cells in vitro; moreover, the mechanism of action of Les-3266 in cells is mediated probably by interaction with the PPARγ receptor pathway, which needs in-depth study.
The article is sanctified to the problem of understanding the concept «conflict of interest» and its characteristics in the legal positions of Administrative Court of Cassation as a part of Supreme Court of Ukraine. It is educed that such that such legal positions touch the correct definition of characteristics of private interest, potential and real conflict of interest, finding out people who are subordinated to a person who is authorized to perform state or local self-government functions, and it can causes potential or real conflict of interest. In particular,in legal positions of Supreme Court explain that restricting the joint work of close people is a type of conflict of interest, because it causes a private interest from a person who is authorized to perform the functions of state or local self-government. It is important to note that close people are people who live together, have common life, mutual rights and duties. Setting only of living together of a person who is authorized to perform the functions of state or local self-government and a subordinated person does not mean that they are close people. So, relations of subordination do not mean that the conflict of interest is real in this situation. A potential or a real conflict of interest arises in a situation where a close person of a person who is authorized to perform the functions of state or local self-government does not work under his authority, but carries out person’s activities in the area of jurisdiction of the body in which this person works. Legal and social (private) relations which determine the emergence of property or non-property interest are important in determining the existence of private interest. Private interest can have the consequence both positive influence (a person has aspiration to thank and others like that) on a situation and negative (to inflict troubles and others like that). These legal positions can be used in bringing the guilty persons to administrative responsibility under the Code of Administrative Offenses. Key words: conflict of interest, potential conflict of interest, real conflict of interest, private interest, relatives, jurisdiction.
In this paper, the structural properties of a function are characterized by moduli of continuity. The classical Hardy–Littlewood theorem describes a relation between the smoothness of the analytic function boundary values at the boundary of its analyticity and the growth rate of the modulus of its higher-order derivatives. An analogue of the Hardy–Littlewood theorem has been obtained for functions from the class Hp and higher-order moduli of continuity.
Exploring better Gamma, X-Ray and IR-Mid-R detectors, adequately sensitive to ambient temperatures and environmental conditions, is highly desirable. Therefore, following this path, we present detecting opportunities, based on data of experimental and theoretical investigation of the electronic and optical properties, photocurrent behavior at different bias voltages as well as the reflection for the He-Cd cw laser after irradiation by three different IR laser wavelengths, for recently grown TlPb2BrI4 single crystal with strong anisotropic, two-dimensional (2D) layered structure. The X-ray photoelectron spectroscopy brings data on binding energy values of core levels of TlPb2BrI4 for both as-grown and Ar⁺-ion-treated crystal surfaces as well as for elucidation of the energy distribution of the valence electronic states. In opposite to well-known IR-detector materials, TlPb2BrI4 crystal surface shows high chemical stability concerning Ar⁺-ion bombardment. Further, we carry out ab initio band-structure calculations to gain curves of total and partial densities of states and to elucidate the principal optical constants of TlPb2BrI4. The present studies indicate that, in spite of the fact that the TlPb2BrI4 crystal contains two very hazardous/toxic chemical elements, thallium and lead; however, it is chemically stable and reveals very low hygroscopic behavior when being exposed to environmental conditions.
This study presents the research results of the activities of the United States and China as the major global competitors in the field of cybersecurity. We have established the nature and trends of the confrontation, explored the goals and means of cyber influences in the confrontation between two states in this area, and identified directions for the development of the competition between the United States and China in the field of cybersecurity. Today, the United States and China are the world leaders in cyberspace and the information (cyber) security sector. The United States remains the undisputed world leader in cybersecurity, but China is rapidly closing the gap, relying on the strong potential of human and economic resources in cyberspace. From the beginning of the second decade of the XXI century. countries have been accusing each other of cyberattacks for economic purposes and cyber espionage. The United States has pointed to the People's Liberation Army's (PLA) leading role in organizing cyberattacks, and China has made similar allegations against the US intelligence. Despite attempts to reconcile policies in this area, tensions between the United States and China over cyber-building are growing. And since the beginning of the 2020s, politically motivated influences on information systems have become the target of cyberattacks. The United States notes a change in China's cyberattack strategy from regular cyber espionage to prosecuting political and security goals. Additionally, systematic control over the sources of cyber threats has been transferred from the PLA to the security structures of China. China also accuses the United States of using cyber influences to increase world hegemony and using cyber threats in the arms race. Beijing makes these statements from the standpoint of its own “multipolar” world strategy, which is threatened by the activities of the Joe Biden administration, aimed at consolidating Western countries in the face of cyber threats from China. The field of cybersecurity in US-China relations is becoming increasingly important in terms of the security strategies of these two world leaders. Each of them uses cyber tools as a tool of cyber influence, as well as a tool for strategic communication at the level of relations with strategic partners. Therefore, these issues will become increasingly important in terms of research interests, in particular the implementation of foreign policy interests in relations with these countries.
The article analyzes the polemical socio-religious thought in Ukraine after the Union of Brest and the Union of the Kyiv Metropolitanate with Rome, aimed at finding the lost Orthodox tradition and reviving the idea of “God’s protection” of the city of Kyiv in the Russian Orthodox intellectual tradition of the early 17th century. After-union period in Ukrainian realities is characterized as crisis in the sense of decline of religious life, Russian bourgeoisie and fraternal movement and deviation from the policy of support of the Orthodox princely families. The entire plan of church reform, cultural and national revival of the “Commonwealth of the Russian People” was undermined in its foundations. Therefore, the intellectual religious thought of the early 17th century took into account the memory of the “good old days”, when national (regional) identity based on the Orthodox tradition was searched. However, from the point of view of the continued existence of the Orthodox Church, the defeat was only partial, as K. Ostrozkyi and his supporters among the nobility, clergy and burghers managed to preserve the Orthodox Church structure. The Cossacks demanded a rethinking of this new reality by intellectuals of the post-Brest era and Ukrainian polemicists were forced to look for an independent base for their socio-religious thought. The way out of the crisis was understood by Petro Mohyla, who was ready to recognize the primacy of the Pope in order to preserve the internal independence of the Church.
This article analyzes importance of the Roman Catholic Church in Volhynia in the interwar period. The article reveals the process of formation of the Roman Catholic Church in Volhynia, and special attention is paid to the interwar period. Roman Catholic centres were in Volhynia from ancient times, and have become an integral part of its history. As the city was inhabited by many different nationalities and, consequently, many different religious denominations, the city managed to maintain peace and respect for religious freedom for each of the communities. However, during the reign of the Russian Empire in Volhynia, the situation became more complicated because the tsarist government did not want to support previous agreements with the Church. After the October coup and the war, vast territories of the Lutsk-Zhytomyr diocese were divided between Poland and Soviet Russia by a treaty signed in 1921 in Riga. As Lutsk was a part of the then Poland, in 1925 Pope Pius XI revived a separate diocese of Lutsk. On December 14, 1925, Bishop Adolf Petro Shelonzhek was appointed Bishop of Lutsk. In particular, the figure of Adolf Petro Shelonzhek deserves special attention. The article also analyzes the life of the future bishop. From the beginning of his ministry, the Lutsk Ordinary carried out active pastoral and organizational activities. One of the greatest achievements of Adolf Petro Shelonzhek was the convening of the first diocesan synod in 200 years, which took place in 1927. Particular importance is the description of his active work as a religious and political figure. Special attention is paid to his active pastoral work as Adolf Petro Shelonzhek was an outstanding figure in the life of the Lutsk diocese.
The paper investigates the optimization of ecosystem services of podzolized heavy loamy chernozem (black soil) as a result of the cultivation of the perennial energy culture of Miscanthus x giganteus. The research was conducted on an experimental land plot during 2016–2021. No fertilization was applied to the soil during the experiments, and over the years of research, the growing seasons were accompanied by abnormal droughts, but even under such conditions, the plants of Miscanthus x giganteus gradually increased their yield. At the initial stage of research, in the third year of cultivation, dry biomass of Miscanthus x giganteus was obtained at 14.3 t/ha, in the fourth year–18.6 t/ha, and already in the fifth and sixth years, 21.7 and 24.5 t/ha, respectively. That is, energy-wise, the harvest for the last year was equivalent to 15.9 tons of coal or 12,618 m3 of natural gas. Cultivation of Miscanthus x giganteus on black soil for six years has improved the provision of its ecosystem services, regulation, and ecosystem maintenance services. The possibility of growing perennial energy crops on agricultural soils has been proven by obtaining a significant amount of biomass and a positive phytoremediation effect on the soil by reducing erosion, preserving biodiversity, sequestering carbon, and sustainably improving the ecological situation.
Review on the publication: Western Ukrainian People's Republic 1918-1923. Encyclopaedia Vol. 1: A-Ж. Ivano-Frankivsk : Manuscript-Lviv, 2018. 688 p.; West Ukrainian People's Republic 1918-1923. Encyclopaedia Vol. 2: З-O. Ivano-Frankivsk : Manuscript-Lviv, 2019. 832 p.; West Ukrainian People's Republic 1918-1923. Encyclopaedia Vol. 3: P-С. Ivano-Frankivsk : Manuscript-Lviv, 2020. 576 p.; West-Ukrainian People's Republic 1918-1923. Encyclopaedia Vol. 4: T-Я. Ivano-Frankivsk : Manuscript-Lviv, 2021. 688 p. (Head of the Editorial Board I. Tsependa, Head of the Editorial Board M. Kuhutiak).
Series glasses with compositions (100–х-y) Ga2S3 – х La2S3 – y Er2S3 (х = 30, 35, 40; y = 0, 1, 3 mol.%) were synthesized and their optical properties were examined. Glass-forming region for the novel La2S3–Ga2S3 system was determined. Composition−dependent optical absorption spectra within the spectral range 480–1020 nm and photoluminescence (PL) under excitation by laser radiation with 532 nm wavelength were measured. The PL maxima were found at 660, 810, 860, 980 and 1540 nm. The origin of the excited states in Er³⁺ ions was analyzed using an energy diagram. PL decay kinetics processes were analyzed in detail, within the frame of the two exponents model. This one indicates that the Erbium ions emitting in both red and IR spectral ranges are embedded in the glass matrices a like as separate ions or form clusters of erbium ions. The presented research results along with literature data indicate a wide opportunity for potential applications like thermal and radiation sensors, non-linear optical triggers, up-converters, contactless thermometers or active media for IR lasers.
We report on successful synthesis of single-phase high-temperature (HT) orthorhombic modification of Cu2HgGeS4 and studies of its electronic and optical properties from a viewpoint of experiment and theory. In particular, we have made measurements of the XPS core-level and valence-band spectra of the HT-Cu2HgGeS4 modification and calculated density of states. The calculations are carried out within a framework of density functional theory and using varieties of techniques. We have realized that the best agreement of the theory and experiment is observed when we use in the calculations the modified Becke-Johnson (mBJ) functional as refined by Tran-Blaha and consider also the Hubbard correction parameter U and spin-orbit coupling (SOC). The calculations demonstrate that main contributions of sulfur 3p states occur near the topmost and upper part of the HT-Cu2HgGeS4 valence band, copper 3d states dominate in its central part, the lower part is prevailed by contributions of mercury 6s and germanium 4p states, whereas near the valence band bottom the biggest contributions come from mercury 5d states. The theoretical predictions are verified experimentally. The calculations reveal that the HT-Cu2HgGeS4 modification is a direct band gap semiconductor. The principal optical constants are elucidated following first-principles calculations of the quaternary sulfide under consideration.
A comprehensive theoretical study of the structure, electronic, optical, and elastic properties of ternary semiconductor silver thiogallate crystal AgGaS2 is carried out based on the density functional theory and dipole electron shifting model (DES) for finding a structure–properties relationship. The deformation and displacement parameters, describing the deviation of the structural parameters of AgGaS2 from ideal chalcopyrite structure, are determined. It is noticed that the significant discrepancies concerning peculiarities of the band structure between initial results of the DFT‐based calculation and the experiment for the titled crystal have been efficiently eliminated by choosing the proper DFT + U approach. By utilizing the calculated dielectric function for two principal directions, the refractive indices and extinction coefficients dispersions are determined. For the first time, the linear electro‐optic properties, electrogyration coefficients, and second‐order nonlinear optical coefficients of AgGaS2 crystals are calculated in the frame of the DES model. The elastic properties of the AgGaS crystal are analyzed in the frame of the calculated full matrix of elastic coefficients. A number of parameters, such as Young's modulus E, Poisson's ratio ν, bulk B, and shear G moduli are predicted for the crystal. The calculated anisotropy coefficients for the moduli show very good agreement with ones available from experiment. The structural, electronic, optical, and elastic properties of AgGaS2 crystal are calculated using the DFT and dipole electron shifting model (DES). The deformation and displacement parameters from ideal chalcopyrite structure are determined. In addition, electro‐optical properties, electrogyration coefficients, and nonlinear optical coefficients are calculated by the DES model. The Young's modulus, Poisson's ratio, bulk and shear moduli and their anisotropy show very good agreement with experiment.
Today, together with the recognition of the tourism industry as one of the priorities in the economy of Ukraine, quite active and effective activities have been launched to build a structure of prerequisites for achieving the most effective level of its functioning. At the same time, we understand that to achieve the most successful functioning of the market of tourist services, it is necessary to initiate efforts to overcome the economic crisis and stop military events in Ukraine. We can witness that the market of needs services is becoming increasingly important as a mandatory component in the languages of modern market relations. The tourism industry is a leading field of activity in many countries worldwide. Its development allows you to actively use the most popular and valuable natural resources, ensure job creation, significantly improve the economic, environmental, and social situation, and expand investment space. In Ukraine, the sphere of tourist services has not yet taken its rightful place in services and the economy in general. Therefore, there is a need to substantiate various processes implemented in tourism services at the scientific level, with due regard for national and regional market realities, both in the market and its economic and social situation. An important aspect is also the socio-economic development of the state’s regions, which reflects the continuity and stability of regional tourism markets. Among the many problems facing the balanced development of regional tourism, markets ensure the appropriate level of their competitiveness, both between each other and internationally. In our country, tourism began to gain its development at the whole level not so long ago because it did not have a total base for its formation. At the same time, forming a significant share of state, regional, and local budgets and being a necessary “plane” of market circulation, problems in regulating tourism in the regions are the focus of research while forming further and important competing principles. Therefore, today, we need to implement our study by rating the indicators of infrastructural development of the Western regional market of tourist services in Ukraine.
The review summarizes and systematizes the literature data on the use of 5(4)-aminopyrazoles in the synthesis of pyrazolo[3,4-b]- and pyrazolo[4,3-b]pyridines. The synthetic methods are classified on the basis of how well studied the pyrazolopyridine fragment is, i.e from more to less studied. The bibliography of the review includes 91 references published over the last two decades.
Purpose: To construct a realistic physical model of viscoelastic retinal stretching and, on its basis, derive a universal quantitative criterion of irreversible retinal deformations during age-related macular degeneration. Methods: In this work, standard methods of nonlinear fracture mechanics of ductile and viscoelastic materials were applied to study the evolution of retinal deformation progress in patients with neovascular age-related macular degeneration in the area of large druses or subretinal or sub-retinal pigment epithelium fluid accumulation. A two-dimensional rhombic model of viscoelastic Kelvin-Feucht primitives was used to reconstruct the parameters included in the approximation of the creep strain growth rate. A clinical case of a patient with age-related macular degeneration and retinal pigment epithelium detachment in the macula was taken as a basis for theoretical research. The patient underwent retinal optical coherent tomography on DRI Swept-Source OCT. Results: A closed realistic theoretical model of retinal stretching in the projection of retinal pigment epithelium elevation due to its detachment or drusen based on a two-dimensional rhombic Kelvin-Feucht primitives model was constructed. The calculation of stress in the retinal tissue with consistent consideration of creep effects was performed. Conclusions: The time of critical retinal loading - a new quantitative criterion for the irreversibility of retinal stretching in age-related macular degeneration is proposed. This criterion allows the prediction of the functional outcome of antiangiogenic therapy in patients with age-related macular degeneration with identical initial retinal morphometric parameters.
In early 2020, the traditional form of full-time education has becomeunacceptable, which has made the educationalsystem to change dramatically. Educators had to find new ways and tools for transferring knowledgeto students. The aim of this work was to study the impact of the individualization of education on the effectiveness of educational services provided to Natural Sciences teachers in the context of Covid-19. The study involved semi-structured interviews, as well as close-ended questionnaires. The analysis of variance, Cohen’s coefficient and Statictica software application were also used. It was found in the sampleof futurenatural sciences teachers that the individualization of education can promote higher efficiencyof distance learning. This requires skillful handling of a wide variety of didactic materials and educational resources, their adaptation to the individual capabilities of the student, his or her expectations of learning and didactic goals. It was found that the individualization of education helpsstudents to feel less overload, stress, tension, lack of time. They learned to plan and self-organize, their self-motivation and responsibility for the completed work increased.
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144 members
Zholt Kormosh
  • Chemistry and Technology
O. V. Parasyuk
  • Department of Inorganic and Physical Chemistry
Lyudmyla V. Piskach
  • department of inorganic and physical chemistry
Myroslava Zabokrytska
  • Department of Geography
Voly 13, 43018, Lutsk, Volyn, Ukraine