Russian - Armenian (Slavonic) University
Recent publications
In graph theory, an edge coloring of a graph is a coloring of the edges, meaning an assignment of colors to edges. Edge coloring can be described as function , where is the set of graph edges and is the set of natural numbers. Graph coloring has been studied as an algorithmic problem since the early 1970s. The main objective is to minimize the number of colors while coloring a graph. The smallest number of colors required to color a graph with specified conditions is called chromatic number of that graph and is denoted by . By a result of Holyer [1], the determination of the chromatic index is an hard optimization problem. The NP-hardness give rise to the necessity of using heuristic algorithms. In particular, we are interested in upper bounds for the chromatic index that can be efficiently realized by a coloring algorithm.
Poly (ADP-ribose) polymerase 1 (PARP1) has high therapeutic value as biomolecular target for research and development of small molecules with antineoplastic activity, since it is upregulated in many cancers, especially in ovarian and BRCA 1/2 mutated breast cancers. Decades of investigation of PARP inhibitors (PARPi) have led to the approval of several drug compounds, however clinical application of PARPi in cancer therapy is limited due to a number of factors, including low selectivity, weak affinity and undesired side effects. Thus, identification of novel drug-like chemical compounds with alternatives to the known PARPi chemical scaffolds, binding modes and interaction patterns with amino acid residues in the active site is of high therapeutic importance. In this study we applied a combination of ligand- and structure-based virtual screening approaches with the goal of identification of novel potential PARPi.
Macroeconomic policy in Armenia over the past 30 years has led to a slowdown in economic growth. This, in turn, entails the need to revise approaches to macroeconomic regulation, as well as to search for key drivers of economic growth, which the state should emphasize in the future macroeconomic policy. The aim of this research is to analyze and assess the main drivers of economic growth in Armenia. We have employed the methods of statistical and comparative analysis, deductive analysis, as well as the analysis of historical data and the current state of the problem. The paper examines the key drivers of economic growth in Armenia, as well as periods of both a stable macroeconomic environment and economic crises, from the point of view of the efficiency and optimality of macroeconomic regulation. The current study identifies the most important sectors of the economy, analyses macroeconomic policy regulation in Armenia, and assesses the impact of such policies on economic growth in the country. The results show that today’s macroeconomic regulation can be considered ineffective, which certainly has a negative effect on the rate of economic growth. The key conclusion of the research is the thesis that it is urgent to develop new socio-economic policy approaches to ensure sustainable economic growth in the future and to emerge quickly from future economic growth crises without restricting or halting economic activity.
The present study reveals a simple, non-toxic and eco-friendly method for the "green" synthesis of Ag-NPs using hydroponic and soil medicinal plant Stevia rebaudiana extracts, the characterization of biosynthesized nanoparticles, as well as the evaluation of their antibacterial activity. Transmission electronic microscopy (TEM) and Dynamic Light Scattering (DLS) analysis confirmed that biosynthesized Ag-NPs are in the nano-size range (50-100 nm) and have irregular morphology. Biogenic NPs demonstrate antibacterial activity against Escherichia coli BW 25,113, Enterococcus hirae ATCC 9790, and Staphylococcus aureus MDC 5233. The results showed a more pronounced antibacterial effect on E. coli growth rate, in comparison with Gram-positive bacteria, which is linked to the differences in the structure of bacterial cell wall. Moreover, the Ag-NPs not only suppressed the growth of bacteria but also changed the energy-dependent H +-fluxes across the bacterial membrane. The change of H +-fluxes in presence of H +-translocating systems inhibitor, N,N'-dicyclohexylcarbodiimide (DCCD), proves the effect of Ag-NPs on the structure and permeability of the bacterial membrane. Overall, our findings indicate that the Ag-NPs synthesized by medicinal plant Stevia extracts may be an excellent candidate as an alternative to antibiotics against the tested bacteria.
This article discusses the possibility of improving the quality of analysis of MRI images of the brain in various scanning modes by using greedy feature selection algorithms. A total of five MRI sequences were reviewed. The texture features were formed using the MaZda software package. Using an algorithm for recursive feature selection, the accuracy of determining the type of tumor can be increased from 69% to 100%. With the help of the combined algorithm for the selection of signs, it was possible to increase the accuracy of determining the need for treatment of a patient from 60% to 75% and from 81% to 88% in the case of using an additional class of data for patients whose accurate result of treatment is unknown. The use of textural features in combination with a feature that is responsible for the type of meningioma made it possible to unambiguously determine the need for patient treatment.
We study the prediction problem for deterministic stationary processes X(t) possessing spectral density f. We describe the asymptotic behavior of the best linear mean squared prediction error σn2(f) in predicting X(0) given X(t), -n≤t≤-1, as n goes to infinity. We consider a class of spectral densities of the form f=fdg, where fd is the spectral density of a deterministic process that has a very high order contact with zero due to which the Szegő condition is violated, while g is a nonnegative function that can have arbitrary power type singularities. We show that for spectral densities f from this class the prediction error σn2(f) behaves like a power as n→∞. Examples illustrate the obtained results.
INTRODUCTION. The world has many times faced cardinal changes triggered by technological development. Creation of the Internet and the emergence of the artificial intelligence have become the major trend of the ongoing changes with the signifi-cant potential to affect all spheres of live, including the military affairs and the geopolitical phenomena in general. In this paper, in particular, we discuss the opportunities and challenges of the rapid technological development in the defense sector in the context of globalization. The pace and the nature of changes in defense dictate the necessity to analyze the current and future challenges of our digitized age in search of adequate and timely legal and strategic practical solutions. Cyber means of warfare are the weapons of the present. Over the past decades, cyber means of warfare have been frequently used against states in the context of international and non-international armed conflicts, as well as outside of such context. Thus, the fundamental scientific questions that arise are the following: a) are the current legal regulations at international and national levels sufficient to address all the challenges caused by the spillover of armed conflicts into the virtual domain and by the future advancement of cyber weapons, and b) are the current cyber weapons or those of the future capable of changing the nature of “war” described by General Carl von Clausewitz yet in the 19th century as a violent method of forcing its political will by one party of the conflict to the other. We have analyzed the above-mentioned questions in the light of the cyber weapons, which already exist and are being used for military purposes, in the light of possible advancement of cyber weapons and integration of AI into them, as well as in the light of the Big Data management. We have reflected on the dangers, which the smart and entirely data driven world would face, from legal and geopolitical perspectives, through the several possible scenarios of development, emphasizing, in particular, the probable military (defense) aspect of data management. While most frequently the specific problems of application of International Law to the traditional cyber warfare situations become subject for academic debates and discussions, we stress the necessity to also analyze the legal and practical implications of further advancement of cyber weapons, as well as the necessity to consider the role of Big Data management in changing the nature of war and, consequently, also the applicable legal solutions. MATERIALS AND METHODS. The works of academics and international scholars in the field of international law and, specifically, international humanitarian law, and military theorists, as well as international treaties, commentaries to international treaties, and national cyber defense and cyber security strategies comprise the theoretical basis for the current paper. The research has been conducted via general and specific scientific methods of cognition, in particular the dialectical method, comparative legal method, method of interpretation, as well as methods of deduction, induction, analysis, synthesis, and others. RESEARCH RESULTS . The ongoing changes taking place in the world have resulted in a situation, when cyber domain is considered one of the traditional war domains. In this context the international community is now debating more flexible interpretations of international legal regulations in order to most efficiently address the new reality. It is also important that states at national level undertake measures to timely and adequately address the challenges already created and those that potentially may take place as a result of the globalization along with the rapid evolution of the cyber technologies and their military use. In the current article we conclude that the categories of the present generation of cyber weapons are lawful. However, the future developments in cyber weapon technologies, as well as the possible quasi-military implications of Big Data management raise many theoretical and practical questions deserving attention. The efforts of the international community and individual states in the field of legal regulation of cyber technologies should be directed toward creating guarantees that the products of the technological development are used for the benefit of humankind. As one of such measures The Authors indicate national cyber security and cyber defense strategies, which according to the Authors, should be elaborated giving due consideration to the possible future developments. DISCUSSION AND CONCLUSIONS. In this paper we analyze the peculiar features of evolution of the world in the 21st century and argue that wars are not static and autonomous phenomena isolated from the global context and all the changes taking place in the world. In particular, we address one of the most popular debates among the scholars in the field of military affairs concerning the issue whether the nature of war has changed or will change overtime, referring to Carl von Clausewitz’s thoughts. With regard to the current generation of cyber weapons, we conclude that even if they might prima facie seem to be inherently indiscriminate (such as, for example, nuclear weapons) in reality cyber weapons are not per se indiscriminate, but rather are weapons with a very high potential of being used indiscriminately or in violation of the principle of discrimination. However, the high potential of indiscriminate use of cyber weapons does not outlaw the cyber weapons as such. We also agree with the widely accepted opinion that the cyber weapons, which are currently used, are sufficiently regulated by the International Law. At the same time, the future tendencies for advancement and improvement of military cyber technologies, inter alia, via integration of artificial intelligence, may seriously call into question the possibility of their application in compliance with the international legal regulations. Finally, the possible scenarios of advancement of Big Data management have led us to the conclusion that big data management per se has the potential of being used as a weapon with less lethal or even non-lethal consequences, however equally effective in enforcing one’s policy as the traditional weapons or potentially kinetic cyber-weapons. If big data analysis at its current stage of development does not produce very accurate predictions, the well-distributed and structured informational flow in the cyber domain is capable of influencing and manipulating behaviours. In such case if Big data monopoly (including both: hardware and soſtware) vests in one of several actor, it could drastically change the nature of war by making the element of violence redundant and consequently alter the geopolitical balance. One of the measures for early response to future challenges, in our opinion, could be through reflecting on lex ferenda in cyber security and cyber defence national strategies. From the analysis of the content of different strategies we could conclude that most states acknowledge cyberspace as a military domain like land, air or maritime, analyse the main specific characteristics of current generation of cyber weapons, and set state objectives and action plan for cyber offense, cyber defense and cyber deterrence respectively. While the future advancement of cyber means of warfare and the quasi-military dimension of the big data management seem to be overlooked by states in general.
The results of comprehensive studies of near-infrared photoluminescence and mid-infrared equilibrium and photoinduced absorption spectra in structures with Ge/Si quantum dots with different doping levels at different optical pumping intensities and different temperatures are presented. Obtained dependences of interband photoluminescence spectra on temperature and optical pumping intensity are explained by the change in the intensities of direct and indirect in real space electron-hole recombination in Ge/Si quantum dots. The spectra of equilibrium and photoinduced absorption of polarized mid-infrared radiation demonstrate peaks associated with transitions of holes from the ground and excited states to continuum states above quantum dots and with optical transitions from the ground states to excited ones.
The sizes of linear and tree-like proofs for any formulae families are investigated in some systems of propositional calculus: in different sequent systems (with quantifier rules, with the substitution rule, with the cut rule, without the cut rule, monotone) and in the generalization splitting system. The comparison of results obtained here with the bounds obtained formerly for the steps of proofs for the same formulas in the mentioned systems shows the importance of the size of proof among the other characteristics of proof complexities. Keywords: The varieties of propositional sequent systems, The generalization splitting system, The proof size and number of proof steps, Exponential speed-up.
According to the UN Sustainable Development Agenda which replaced the Millennium Development Goals (MDGs) and includes components of social, economic, and environmental development, ensuring access to affordable, reliable, sustainable and modern energy sources is the seventh global goal in the system of seventeen interrelated goals developed by the UNGA in 2015. The goal implies operation and development of environmentally friendly national energy systems that will contribute to socio-economic development. To assess the dynamics and development trends of global energy systems, the methods of their quantitative assessment become particularly relevant. In this aspect, the most important tool for assessing the sustainability of global energy is the energy trilemma index developed by WEC and «Oliver Wyman Group» consulting company. The index is a comprehensive assessment of the economic, social, and environmental components of the UN sustainable development program. It allows countries to be quantified by their ability to ensure energy security, energy equity and the environmental sustainability of national energy systems, considering socio-economic and political changes. The paper presents the main methodology for calculating the energy trilemma index and its role in assessing sustainable and safe energy. In 2021, there were changes in the methodology of calculating the index, so it became possible only to compare the dynamics of changes of key components. Based on the indicators of 2021, the main trends in the global energy system are presented. The mechanism of the index components’ influence on the formation of a country’s rating is illustrated. A special attention is given to the analysis of the indicators of energy trilemma index for the Republic of Armenia in 2021, considering the main challenges of the Armenian energy sector and the consequences of the Forty-Four Day War in 2020. The dynamics of main components of energy trilemma index of Armenia is shown through the analysis of the conjuncture and the main development trends of the country’s energy system. The practical significance of the index for shaping the state policy for the energy sector development is emphasized as well.
Public service broadcasters were forced to adapt to the new "normal" in a complex, constantly changing, and competitive international broadcasting environment, where the World Wide Web becomes the most important tool to inform audience. Taking into consideration the following parameters: positioning, engagement, origin of the audience and device for access, the websites of four Public Service Broadcast companies in Europe were examined. In general, the time spent by users on websites is limited, bounce rate parameter is high, the main audience of the broadcasters come from the country itself and the most commonly used device to access the websites are mobile phones and tablets. Presence in social networks was studied in the position of Facebook page availability and number of followers. Results show that websites of the analyzed Public Service Broadcasters are not user friendly, not well-structured, not informative, and do not meet users’ expectations.
The purpose of this paper is to analyse existing theoretical and practical approaches to the explanation of the essence of business clusters. This study observes the nature of clusters, as well as inspects dynamic changes in the perception of a cluster as an agglomeration. The research is based on a literature review, within the scope of which theoretical approaches are divided into four categories, namely the British, Italian, American and Scandinavian visions. Not only does the paper contain detailed examinations of the approaches, but it also reveals an evaluation of each approach from the position of nine measurement criteria that are proposed within a comparative analysis. The choice of implemented criteria is justified by their significance for the description of clusters. Apart from that, the study highlights distinguishing features of all approaches.
There are unique stressors in the spaceflight environment. Exposure to such stressors may be associated with adverse effects on astronauts' health, including increased cancer and cardiovascular disease risks. Small extracellular vesicles (sEVs, i.e., exosomes) play a vital role in intercellular communication and regulate various biological processes contributing to their role in disease pathogenesis. To assess whether spaceflight alters sEVs transcriptome profile, sEVs were isolated from the blood plasma of 3 astronauts at two different time points: 10 days before launch (L-10) and 3 days after return (R+3) from the Shuttle mission. AC16 cells (human cardiomyocyte cell line) were treated with L-10 and R+3 astronauts-derived exosomes for 24 h. Total RNA was isolated and analyzed for gene expression profiling using Affymetrix microarrays. Enrichment analysis was performed using Enrichr. Transcription factor (TF) enrichment analysis using the ENCODE/ChEA Consensus TF database identified gene sets related to the polycomb repressive complex 2 (PRC2) and Vitamin D receptor (VDR) in AC16 cells treated with R+3 compared to cells treated with L-10 astronauts-derived exosomes. Further analysis of the histone modifications using datasets from the Roadmap Epigenomics Project confirmed enrichment in gene sets related to the H3K27me3 repressive mark. Interestingly, analysis of previously published H3K27me3–chromatin immunoprecipitation sequencing (ChIP-Seq) ENCODE datasets showed enrichment of H3K27me3 in the VDR promoter. Collectively, our results suggest that astronaut-derived sEVs may epigenetically repress the expression of the VDR in human adult cardiomyocytes by promoting the activation of the PRC2 complex and H3K27me3 levels.
This article is devoted to the analysis of the occurrences of the term Abxāz in Classical Persian literature and Iranian historiography. Under the term Abxāz, generally, Persian poets and writers implied the whole territory of Georgia and not only proper Abkhazia located on the eastern coast of the Black Sea. New points have been made about the word tamūk in Luγat-i furs by Asadī Ṭūsī, as well as the Abkhaz language, based on a quatrain (rubā‘ī) by Xāqānī.
The present study investigates the intertextual relationship between the Pahlavi “Story of Jōišt ī Friyān” and the biography of Zarathustra, as recorded in pre-modern Zoroastrian sources. The first part of the study contains the presentation and analysis of intertextual fragments within the Pahlavi tale, which can be discerned as referencing the Zoroastrian prophet’s life and deeds, forging an associative link between the central character of the story and the image of Zarathustra. The second part provides an attempt to explain why the author of the story might have considered such a link necessary and what could have inspired him to choose Zarathustra’s image and associate it with his protagonist.
3-{[(1-Methyl-1H-tetrazol-5-yl)imino]methyl}quinoline-2-thiol and 3-{[(2-methyl-2H-tetrazol-5-yl)imino]methyl}quinoline-2-thiol were synthesized. The sequence of the thiol-Michael reaction and the (aza)-Morita-Baylis-Hillman reaction yielded 4-[(1-methyl-1H-tetrazol-5-yl)amino]-2-phenyl-4H-thiopyrano[2,3-b]quinoline-3-carbaldehyde, 4-[(2-methyl-2H-tetrazol-5-yl)amino]-2-phenyl-4H-thiopyrano[2,3-b]-quinoline-3-carbaldehyde, and 4-hydroxy-2-phenyl-4H-thiopyrano[2,3-b]quinoline-3-carbaldehyde. Cytotoxicity and antiviral activity against the A/Puerto Rico/8/34 (H1N1) influenza virus strain in MDCK cell culture were determined for the obtained compounds. The study showed that the replacement of the hydroxyl group in 4-hydroxy-2-phenyl-4H-thiopyrano[2,3-b]quinoline-3-carbaldehyde with a 1-methyl- or 5-amino-2-methyltetrazolyl fragment decreased antiviral activity. At the same time, 3-{[(1-methyl-1H-tetrazol-5-yl)imino]-methyl}quinoline-2-thiol has a higher activity than 3-{[(2-methyl-2H-tetrazol-5-yl)imino]methyl}quinoline-2-thiol. This fact indicates a possible relationship between the arrangement of substituents in the tetrazole ring and the antiviral activity of the tested heterocyclic system. Supplementary information: The online version contains supplementary material available at 10.1007/s10593-022-03083-w.
Background: Heterocyclic compounds and their fused analogs, which contain pharmacophore fragments such as pyridine, thiophene and pyrimidine rings, are of great interest due to their broad spectrum of biological activity. Chemical compounds containing two or more pharmacophore groups due to additional interactions with active receptor centers usually enhance biological activity and can even lead to a new type of activity. The search for new effective neurotropic drugs in the series of derivatives of heterocycles containing pharmacophore groups in organic, bioorganic and medical chemistry is a serious problem. Methods: Modern methodology of drugs involves synthesis, physicochemical study, molecular modeling and selection of active compounds through virtual screening and experimental evaluation of the biological activity of new chimeric compounds with pharmacophore fragments. For the synthesis of new compounds, classical organic methods were used and developed. For the evaluation of neurotropic activity of new synthesized compounds, some biological methods were used according to indicators characterizing anticonvulsant, sedative and antianxiety activity as well as side effects. For docking analysis, various soft ware packages and methods were used. Results: As a result of multistep reactions, 11 new, tri- and tetracyclic heterocyclic systems were obtained. The studied compounds exhibit protection against pentylenetetrazole (PTZ) seizures as well as some psychotropic effects. The biological assays evidenced that nine of the eleven studied compounds showed a high anticonvulsant activity by antagonism with pentylenetetrazole. The toxicity of the compounds is low, and they do not induce muscle relaxation in the studied doses. According to the study of psychotropic activity, it was found that the selected compounds have an activating behavior and anxiolytic effects on the "open field" and "elevated plus maze" (EPM) models. The data obtained indicate the anxiolytic (antianxiety) activity of the derivatives of tricyclic thieno[2,3-b]pyridines and tetracyclic pyridothieno[3,2-d]pyrimidin-8-ones, especially pronounced in compounds 3b-f and 4e. The studied compounds increase the latent time of first immobilization on the "forced swimming" (FS) model and exhibit antidepressant effects; compounds 3e and 3f especially exhibit these effects, similarly to diazepam. Docking studies revealed that compounds 3c and 4b bound tightly in the active site of γ-aminobutyric acid type A (GABAA) receptors with a value of the scoring function that estimates free energy of binding (∆G) at -10.0 ± 5 kcal/mol. Compound 4e showed the best affinity ((∆G) at -11.0 ± 0.54 kcal/mol) and seems to be an inhibitor of serotonin (SERT) transporter. Compounds 3c-f and 4e practically bound with the groove of T4L of 5HT_1A and blocked it completely, while the best affinity observed was in compound 3f ((∆G) at -9.3 ± 0.46 kcal/mol). Conclusions: The selected compounds have an anticonvulsant, activating behavior and anxiolytic effects and at the same time exhibit antidepressant effects.
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246 members
Volodya Harutyunyan
  • general physics and quantum nanostructures
Ruben Elamiryan
  • World Politics and International Relations
Sevak Sargsyan
  • Department of Applied Mathematics
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Yerevan, Armenia
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www.rau.am