Ivane Javakhishvili Tbilisi State University
Recent publications
The accurate simulation of additional interactions at the ATLAS experiment for the analysis of proton–proton collisions delivered by the Large Hadron Collider presents a significant challenge to the computing resources. During the LHC Run 2 (2015–2018), there were up to 70 inelastic interactions per bunch crossing, which need to be accounted for in Monte Carlo (MC) production. In this document, a new method to account for these additional interactions in the simulation chain is described. Instead of sampling the inelastic interactions and adding their energy deposits to a hard-scatter interaction one-by-one, the inelastic interactions are presampled, independent of the hard scatter, and stored as combined events. Consequently, for each hard-scatter interaction, only one such presampled event needs to be added as part of the simulation chain. For the Run 2 simulation chain, with an average of 35 interactions per bunch crossing, this new method provides a substantial reduction in MC production CPU needs of around 20%, while reproducing the properties of the reconstructed quantities relevant for physics analyses with good accuracy.
Background Georgia is an upper middle-income country, which has lower cancer survival rates than most of the countries in the World Health Organization European region, as well as compared to many other post-Soviet states and upper middle-income countries. The purpose of our study was to analyse the cancer stage distribution data of Georgia as a first step towards identifying the areas of early cancer detection in the country that might need improvement or require further research. Methods Descriptive analysis of the population-based cancer registry of Georgia was performed using the data for the period of 01.01.2018–31.12.2019. Results Around 57 % of cancers in males and 56 % of cancers in females were amenable to early detection. At least 35.7 % of these cancers in males and 44.2 % in females were detected early. 15.2 % (n = 964) of male and 35.3 % (n = 3179) of female cancer patients met the age criteria for the respective cancer screening programmes. Breast, colorectal, cervical and stomach cancers contributed to 58.7 % of all late-stage cancers in females. Lung, prostate, colorectal, laryngeal and stomach cancers made up 72.4 % of all late-stage cancer cases among males. At least 83.8 % (n = 1438) of thyroid cancers in females and 84.2 % (n = 246) of thyroid cancers in males were diagnosed at stage I. Moreover, stage I thyroid cancer cases made up 50.7 % of all stage I cancer cases detected in women and 25.6 % of all stage I cancers in men. At least 42.4 % of stage I thyroid cancers in females and 37.4 % of stage I thyroid cancers in males were papillary microcarcinomas. Conclusion The potential of early cancer detection is underutilised in Georgia and there is a need to strengthen screening and especially early diagnosis in the country. The possibility of thyroid cancer overdiagnosis requires further investigation.
In the paper, the stationary and non-stationary fluid flows of large viscosity and low Reynolds number in 2D bounded area are considered. 2D Stokes equation in the area partly filled with the very viscous fluid is studied. Upper bound of the fluid is unknown. Under the influence of certain pressure and body forces, the waves (free surface) in the fluid are generated. The case of the solenoidal body force and a harmonic pressure is considered. Solutions of the Stokes system with the appropriate initial-boundary conditions by means of the methods of conformal mapping and integral equations are obtained. It is assumed, that the pressure is given. The existence and uniqueness of the solution is proved. The solutions of the non-stationary problem are derived by means of the step-wise approximation method. The profiles of free surfaces for the different pressure are plotted by means of Maplesoft.KeywordsConformal mappingFree boundaryFredholm integral equationReynolds numberStep-wise approximationStokes flow
Background and aims: In 2015, the country of Georgia launched an elimination program aiming to reduce prevalence of Hepatitis C virus (HCV) infection by 90% from 5.4% prevalence (~150,000 people). During the first 2.5 years of the program, 770,832 people were screened, 48,575 were diagnosed with active HCV infection, and 41,483 patients were treated with direct-acting antiviral (DAA) based regimens, with >95% cure rate. Methods: We modelled the incremental cost-effectiveness ratio (ICER) of HCV screening, diagnosis, and treatment between April 2015 and November 2017 compared to no treatment, in terms of cost per quality-adjusted life year (QALY) gained in 2017 US dollars, with 3% discount rate over 25 years. We compared the ICER to willingness-to-pay (WTP) thresholds of US$4357 (GDP) and US$871 (opportunity-cost) per QALY gained. Results: The average cost of screening, HCV viremia testing, and treatment per patient treated was $386 to the provider, $225 to the patient, and $1042 for generic DAAs. At 3% discounting, 0.57 QALYs were gained per patient treated. The ICER from the perspective of the provider including generic DAAs was $2,285 per QALY gained, which is cost-effective at the $4357 WTP threshold, while if patient costs are included it's just above the threshold at $4,398/QALY. All other scenarios examined in sensitivity analyses remain cost-effective except for assuming a shorter time horizon to end of 2025, or including list price DAA cost. Reducing or excluding DAA costs reduced the ICER below the opportunity-cost WTP threshold. Conclusions: The Georgian HCV elimination program provides valuable evidence that national programs for scaling up HCV screening and treatment for achieving HCV elimination can be cost-effective.
An antimicrobial polyacrylic silver salt (freshly prepared, stored for one year and modelaged) was studied by physical–chemical techniques for nanoparticle detection. In all cases, this salt represents a composite of radical-enriched macromolecules and silver(0) nanoparticles. As time passed, the initial small spherical nanoparticles were converted into larger non-spherical silver nanoparticles. The initial highly water-soluble antimicrobial solid nanocomposite almost loses its solubility in water and cannot be used as an antimicrobial agent. Unlike insoluble solid silver polyacrylate, its freshly prepared aqueous solution retains a liquid-phase consistency after one year as well as pronounced antimicrobial properties. The mechanism of these spontaneous and model-simulated processes was proposed. These results have attracted attention for officinal biomedicinal silver salts as complex radical-enriched nanocomposite substances; they also indicate contrasting effects of silver polymeric salt storing in solid and solution forms that dramatically influence antimicrobial activity.
Regardless of their healthcare systems’ maturity and quality, the COVID-19 pandemic caused a slew of unexpected problems and harmful effects for people worldwide. Georgia responded to the pandemic’s first wave (March–April 2020) with well-managed and well-coordinated activities based on the pandemic management principles: Find-Test-Trace-Isolate-Detect. Epidemiological monitoring, mobility limitations, and practical communication efforts were used to prevent and limit the spread of the infection, resulting in remarkable morbidity and mortality reductions. Due to pandemic fatigue, summer tourism brought increased mobility, disregard for mask-wearing, distancing habits and multiplication of regional clusters and two-rounds of Parliamentary elections with numerous mass meetings. All of these developments culminated in a remarkably different second wave with the pandemic hampering the growth of tourism, a significant sector of the Georgian economy that accounts for 8% of GDP and employs around 150,000 people. It also exponentially increased morbidity and high mortality (40–55 daily deaths) in October–November 2020. The most popular tourist destinations in Georgia are Tbilisi, Ajara, Kvemo Kartli, Imereti, and Mtskheta-Mtianeti. COVID-19 severely harmed Georgia’s tourism industry, especially international arrivals. In 2020, compared to 2019, international tourist visits to Georgia decreased by 80%. This research focuses on how the COVID-19 pandemic affected Georgia’s tourism industry in terms of structure and geography. The study was conducted from March to December 2020. It employs the following methods: data collection, processing, an analysis from official Georgian sources, as well as the results of the authors’ sociological survey, a review of academic and media articles on the subject, and preliminary analysis using GIS technologies. The key finding is that the COVID-19 pandemic had the greatest negative impact on Georgia’s tourism market causing significant economic harm. International tourism dropped sharply, but domestic tourism remained nearly unchanged from previous years, revealing tourists’ new regional preferences.KeywordsCoronavirusHospitality sectorDomestic touristsInternational visitsRegional distinctions
We show that the sQ-degree of a hypersimple set includes an infinite collection of \(sQ_1\)-degrees linearly ordered under \(\le _{sQ_1}\) with order type of the integers and each c.e. set in these sQ-degrees is a hypersimple set. Also, we prove that there exist two c.e. sets having no least upper bound on the \(sQ_1\)-reducibility ordering. We show that the c.e. \(sQ_1\)-degrees are not dense and if a is a c.e. \(sQ_1\)-degree such that \(o_{sQ_1}<_{sQ_1}a<_{sQ_1}o'_{sQ_1}\), then there exist infinitely many pairwise sQ-incomputable c.e. sQ-degrees \(\{c_i\}_{i\in \omega }\) such that \((\forall \,i)\;(a<_{sQ_1}c_i<_{sQ_1}o'_{sQ_1})\).
By unpacking major views of and dynamics towards the Black Sea region from the Georgian perspective, this analysis addresses two questions: What are Georgia’s key perceptions of the Black Sea region? And which role does the Black Sea play in strengthening Georgia’s economic and security resilience in a quickly changing environment marked by geopolitical and geo-economic competition? The article concludes with thoughts on the region’s future and the role of the EU, Georgia’s closest partner, in it.
Background: Prevention of Type 2 diabetes mellitus (T2DM) requires a modifying effect on the pathological processes inducing the β-cell dysfunction. Objectives: the comprehensive study of the violation of rheological parameters in patients with different stages of diabetes and identification of possible links between these alterations with the intensity of the oxidative stress in the patient's body. Methods: 60 patients with IR, prediabetes, T2DM and healthy volunteers were included. Full range of the rheological parameters of the patients' blood - the indicators of erythrocytes aggregation index (EAI), the relative deformability of the erythrocytes membranes (ERDI), blood plasma viscosity (BPV), and oxidative stress intensity (OSI) were examined. Results: In patients with insulin resistance (IR), prediabetes, and T2DM the ERDI was statistically significantly lower and BPV - higher compared to control; a significant increase in EAI was detected in the patient group with prediabetes and T2DM compared to the control. Conclusion: The level of rheological disorders in patients increases with the increase of the level of carbohydrate metabolism disorders and intensity of oxidative stress and reaches a maximum during manifested diabetes. Diagnosis of hemorheological disorders and OSI in T2DM can serve as an early marker of target organ damage possibility.
Unlike some European countries, the involvement of radical right-wing forces in Georgian politics and the support of a certain part of the society for them is a relatively new phenomenon in Georgia’s politics. This has resulted in a growing interest in the study of the topic among Georgian academic circles. However, the defining and applying the concepts of radicalism and extremism regarding Georgian right-wing forces are different. By comparing the major approaches to the concepts of right-wing radicalism and extremism this paper aims to critically review and analyze perceptions from Georgian academia.
The research aimed at studying the phenomenological structure of metabolic syndromes in overweight and obese school-age children. The cohort of 210 students participated in the cross-sectional study. Among them 84 children (40%) were overweight/obese and 126 students (60%)—with normal weight. The incidence of abdominal obesity and arterial hypertension were studied and lipid profile was assessed in obese children. The results of research revealed the early manifestation of abdominal obesity (14.3%-16.7%), arterial hypertension (the elevation of systolic pressure—27.4%, the increase in diastolic pressure—10.7%) and hypercholesterolemia (9.5%) in the population of overweight/obese school age children, which allows to take prompt corrective actions on metabolic syndrome and reduce the risk of its formation.
It is proved that the maximal operators of subsequences of Cesàro means with varying parameters of two-dimensional Walsh-Fourier series is bounded from the dyadic Hardy spaces HpI\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$H_{p}\left( {\mathbb {I}}\right) $$\end{document} to LpI\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$L_{p}\left( {\mathbb {I}}\right) $$\end{document}. This implies an almost everywhere convergence for the subsequences of the summability means.
Objectives. Amyotrophic Lateral Sclerosis (ALS) is a disease characterized by a progressive degeneration of upper motor neurons (MNs) in the motor cortex and lower MNs in the brainstem and the spinal cord. It is still unclear where the motor neuron dysfunction begins and the factors that cause motor neuron degeneration – whether it is a dying forward process of the MN from the cortex, or dying back phenomenon in which motor neuron degeneration starts distally at the nerve terminal or at the neuromuscular junction (NMJ) and progresses toward the cell body. The muscle contribution in ALS development, through NMJs disassembly, is still a matter of debate. Recent studies demonstrate the involment of neuromuscular junction discharges in the early stage of ALS. Methods and materials. We described 4 patients with ALS, among them 3 male and 1 female, aged 55-61. ALS diagnosis is based on clinical signs, EMG study (Awaji criteria,2008), neuroimaging and blood and urine tests. Result. At the early stage of the disease only asymmetric ptosis and diplopia were noted, which did not improved on pyridostigmine or steroids.Antibodies against Achr receptor was positive only in one patient. Thymoma was excluded. Neurophysiological study showed only marked neuromuscular transmition failure in orbicular oculi, there were no clinical and EMG signs of motor neuron damage. Approximately 2 years later, all four patients developed clinical and electromyographic signs of ALS. Conclusion. The result of the present research support the cruel role of NMJ disorders in ALS pathogenesis and its possible employment as an efficient early marker of the disease. Key words: ALS, NMJ, “dying back”
We develop the impurity lattice Monte Carlo formalism for the case of two distinguishable impurities in a bath of polarized fermions. The majority particles are treated as explicit degrees of freedom, while the impurities are described by worldlines. The latter serve as localized auxiliary fields, which affect the majority particles. We apply the method to non-relativistic three-dimensional systems of two impurities and a number of majority particles where both the impurity–impurity interaction and the impurity–majority interaction have zero range. We consider the case of an attractive impurity–majority interaction, and we study the formation and disintegration of bound states as a function of the impurity–impurity interaction strength. We also discuss the potential applications of this formalism to other quantum many-body systems.
We consider the Cauchy problem for a second-order nonlinear evolution equation in a Hilbert space. This equation represents the abstract generalization of the Ball integro-differential equation. The general nonlinear case with respect to terms of the equation which include a square of a norm of a gradient is considered. A three-layer semi-discrete scheme is proposed in order to find an approximate solution. In this scheme, the approximation of nonlinear terms that are dependent on the gradient is carried out by using an integral mean. We show that the solution of the nonlinear discrete problem and its corresponding difference analogue of a first-order derivative is uniformly bounded. For the solution of the corresponding linear discrete problem, it is obtained high-order a priori estimates by using two-variable Chebyshev polynomials. Based on these estimates we prove the stability of the nonlinear discrete problem. For smooth solutions, we provide error estimates for the approximate solution. An iteration method is applied in order to find an approximate solution for each temporal step. The convergence of the iteration process is proved.
Naturally occurring antibodies to tumour antigens are gaining interest as clinically important cancer biomarkers for early diagnosis, prognosis and for the development of anti-cancer therapeutics. The glycoprotein αβ heterodimer hormone human chorionic gonadotropin (hCG) and its β subunit (hCGβ) are produced by various cancers, and their increased serum levels correlate with poor prognosis. We have previously reported that patients with benign ovarian cysts, but not the malignant tumours, were characterized by augmented serum levels of naturally-occurring IgG antibodies to hCG and hCGβ. Here we further characterise these antibodies in patients with ovarian cysts. IgG and IgM antibody binding to whole hCG, hCGβ, hCGα, hCGβ C-terminal peptide (hCGβCTP), and the hCGβ core fragment (hCGβCF) were measured in the sera from 36 patients with ovarian cysts and 12 healthy non-pregnant women using a standard ELISA. IgG subclass usage and affinity was also determined together with cross-binding to whole hCG and its subunits of four selected commercial monoclonal antibodies generated against ovarian cyst mucins. Our results showed that 91.7% of the sera tested contained elevated IgG, but not IgM antibodies to one or several antigens, with an overwhelming prevalence of high affinity IgG2 indicating their binding to carbohydrate epitopes and possibly ovarian cyst mucins. Anti-mucin commercial antibody ab212418 (Abcam) produced against Gal1-3GalNAc, exhibited strong cross-binding to hCGαβ, hCGβ, hCGα and hCGβCTP. The protective anti-cancer potential of these antibodies will be further investigated and could lead to the development of novel treatment strategies for ovarian cancer.
This study explores the relationship between the business environment, economic growth, and funding sources of Chinese small- and medium-sized enterprises (SMEs) to determine the relevance of the business environment for technological SMEs. The agency theory was used as a theoretical framework to describe how asymmetric information among SMEs and borrowers affects SMEs’ financial decisions as well as China’s investment climate and GDP growth. A binary logistic test was used to assess the financing of SMEs and business development for economic recovery after the pandemic in China. Data from the World Economic Forum and Development Bank were examined. According to the results, funding (e.g., formal and informal) under the banking structure and tax regulation may potentially boost standard credit choices and lower casual credit choices. Consequently, it has demonstrated a considerable impact on GDP growth for technologically small and medium-sized enterprises. This study is the first to examine the asymmetric information and institutional theory regarding funding a café. These findings are essential for business leaders and policymakers concerned with the financial health of small and medium-sized enterprises. Policy implications for important stakeholders are also included in this study.
In this article, a serially connected dual column liquid chromatography-tandem mass spectrometry (LC-MS/MS) method is described for the simultaneous separation and enantioseparation of proteinogenic amino acids. For this purpose, different achiral and chiral stationary phases (CSP) and mobile phase compositions have been tested. As a result of the optimization studies, the best enatioseparation for amino acids were achieved with a combination of zwitterionic and crown ether stationary phases using a gradient of two mobile phases: A (water:TFA 99.5:0.5, % v/v) and B (acetonitrile:ethanol:TFA 85:15:0.5, % v/v/v). The developed method provided simultaneous enantioseparation of all proteinogenic amino acids under this study including isomeric and isobaric ones except for proline. The method was successfully applied to human lung adenocarcinoma cells (A549) and healthy human lung epithelial cells (BEAS-2B) cultivated with D-amino acid containing cocktails in order to evaluate D-amino acids transfer rate in normal and cancer lines. The D/L amino acid ratios were different in cancer and normal cell lines cultivated as mentioned above for aspartic acid, cysteine, methionine, phenylalanine, and serine.
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3,793 members
Dimitri Kordzaia
  • Faculty of Medicine
Ushangi Goginava
  • Department of Mathematics
Marina Rukhadze
  • Institute of Physical and Analytical Chemistry
Giorgi Macharashvili
  • Scientific Research Institute for High Energy Physics, Dept. of Experimental Physics
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