Institute for Information Technologies, Kragujevac

Permanent URI for this collectionhttps://dspace.unic.kg.ac.rs/handle/123456789/13385

Institute for Information Technologies covers several different fields of scientific studies through the exchange of information technology which covers the Faculty of Science, technical-technological studies, medical studies, biotechnical and social studies. By covering different fields of studies, the Institution creates a collaboration between the research groups of every field mentioned above, and by doing so it provides a better quality in research. As a result of its activities, the Institution provides the possibility of multidisciplinary research and collaboration of different researches. By following all of the latest research trends in modern science, and with the constant growth of computer science along with informational-communicative technology, the main idea of the Institution will be to develop this type of network.

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Scientific research of the Institution is focused on fundamental, applied research and basic focused research. It covers research programs in the fields of technological development, programs for knowledge transfer, and the stimulative use of scientific research results.

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2,4-Diketo esters: Crucial intermediates for drug discovery
(2020) Joksimović N.; Janković, Nenad; Davidovic G.; Bugarčić Z.
© 2020 Elsevier Inc. Convenient structures such as 2,4-diketo esters have been widely used as an effective pattern in medicinal chemistry and pharmacology for drug discovery. 2,4-Diketonate is a common scaffold that can be found in many biologically active and naturally occurring compounds. Also, many 2,4-diketo ester derivatives have been prepared due to their suitable synthesis. These synthetic drugs and natural products have shown numerous interesting biological properties with clinical potential as a cure for the broad specter of diseases. This review aims to highlight the important evidence of 2,4-diketo esters as a privileged scaffold in medicinal chemistry and pharmacology. Herein, numerous aspects of 2,4-diketo esters will be summarized, including synthesis and isolation of their derivatives, development of novel synthetic methodologies, the evaluation of their biological properties as well as the mechanisms of action of the diketo ester derivates. This paperwork is expected to be a comprehensive, trustworthy, and critical review of the 2,4-diketo ester intermediate to the chemistry community.
3D HeLa spheroids as a model for investigating the anticancer activity of Biginelli-hybrids
(2021) Djordjic Crnogorac, Marija; Matic, Ivana; Damjanovic, Ana; Janković, Nenad; Krivokuca, Ana; Stanojkovic, Tatjana
In previous study, we examined the anticancer effects of novel Biginelli-hybrids against HeLa cell line on 2D monolayer culture. The five most effective compounds were chosen for further analysis of their anticancer activity against HeLa spheroids. Using the 3D models implies the possible differences in anticancer effects and mechanisms of activity of tested compounds. The compounds 4c and 4d exerted the strongest activity against 3D HeLa spheroids and induced to some extent loosened cell-cell contacts in spheroids, leading to the largest reduction in the diameter of the spheroids. Additionally, the highest accumulation of the cells in the subG1 phase of the cell cycle was observed after the treatment with compounds 4d and 4c, while the compound 4f led to the G2/M arrest. The invasion potential of treated HeLa cells in spheroids was monitored by imaging of spheroids embedded in a matrix made of matrigel and collagen and by determination of MMP2, MMP9, and VEGF gene expression levels. The compound 4l did not show invasion-suppressive activity, while the compounds 4c and 4d exerted the strongest anti-invasive activity.
3D modeling and simulation of scoliosis-An integrated knowledgeware approach
(2015) Cukovic, Sasa; Devedzic G.
© 2015 IEEE. This paper presents the application of knowledgeware technologies and CAD systems in the field of 3D non-invasive diagnosis of idiopathic spinal deformity, primarily scoliosis. Automation of the process of generating key diagnostic indicators and a 3D model of the spine, based on digitized dorsal surfaces of patients, is achieved by implementing VBA macros and specialized modules of the CATIA v5 PLM system. Approximation of the central spinal line is performed by B-Spline function whose analysis generates a series of diagnostic parameters that describe the external and internal manifestations of deformities and create preconditions for internet-based monitoring and visualization.
3D reconstruction and computational modeling of solid-fluid interaction in realistic heart model
(2021) Simic, Vladimir; Milosevic, Miljan; Saveljic, Igor; Milicevic, Bogdan; Filipovic, Nenad; Kojić M.
In this report we present basic steps in the 3D reconstruction process of DICOM images and application of our finite element (FE) numerical procedure for loose coupling solid-fluid interaction, to simulate a complete heartbeat cycle for a realistic model of the left heart side. Passive mechanical stresses are calculated using an orthotropic material model based on the experimental investigation of passive material properties of the myocardium, while active stresses are calculated using the Hunter material model. The basic equations for solid mechanics, fluid dynamics, and muscle activation are summarized and model applicability is illustrated on a complex realistic model which includes a left atrium, ventricle, mitral and aortic valves (which serve as fluid domain) coupled with solid wall with realistic fiber directions.
4-[(4-Methylphenyl)sulfanyl]butan-2-one
(2013) Novakovic, Sladjana B.; Leka Z.; Stevanović, Dragana; Muškinja, Jovana; Bogdanovic, Goran A.
In the title compound, C11H14OS, all non-H atoms are essentially coplanar, with a mean deviation of 0.023 Å. In the crystal, centrosymmetrically related molecules are weakly connected into dimers by pairs of C - H⋯O interactions. The dimers are further linked along the a axis by weak C - H⋯π and C - H⋯S interactions.
4-[(Dimethylamino)methylene]-2-ferrocenyl-5-oxo-4,5-dihydrofuran-3- carboxaldehyde: Synthesis, spectral characterization and single crystal X-ray analysis
(2014) Ratković, Zoran; Muškinja, Jovana; Novakovic, Sladjana B.; Bogdanovic, Goran A.; Micskei K.; Vukicevic R.
The title compound 4-[(dimethylamino)methylene]-2-ferrocenyl-5-oxo-4,5- dihydrofuran-3-carboxaldehyde was synthesized by reacting 3-ferrocenoylpropionic acid with Vilsmeier reagent. This result is rather unexpected, since 3-aroylpropanoic acids under these conditions usually give the corresponding 2-aryl-4-chloro-3-formylfurans. 3-Ferrocenoylpropanoic acid is not the only 3-aroylpropanoic acid that exhibit an unusual behavior under the same conditions: 3-thenoylpropanoic acid gave 4-[(dimethylamino)-methylene]-2-(2- thienyl)-5-oxo-4,5-dihydrofuran-3-carboxaldehyde and 4-[(dimethylamino) methylene]-2-(2-thienyl-5-formyl)-5-oxo-4,5-dihydrofuran-3-carboxaldehyde, whereas 3-(4-methoxybenzoyl)propanoic acid yielded 4-[(dimethylamino)methylene]- 2-(4-methoxyphenyl)-5-oxo-4,5-dihydrofuran-3-carboxaldehyde and 2-(4-methoxyphenyl)-5-chloro-furan-3,4-dicarboxaldehyde. Single crystal X-ray analysis was successfully performed for 4-[(dimethylamino)methylene]-2- ferrocenyl-5-oxo-4,5-dihydrofuran-3-carboxaldehyde and 4-[(dimethylamino) methylene]-2-(2-thienyl)-5-oxo-4,5-dihydrofuran-3-carboxaldehyde and their structures were compared. © 2014 Elsevier Ltd. All rights reserved.
4-Ethoxy-3-methoxybenzaldehyde
(2013) Leka Z.; Novakovic, Sladjana B.; Bogdanovic, Goran A.; Muškinja, Jovana; Vukicevic R.
In the title compound, C10H12O3, all non-H atoms are approximately coplanar, with an r.m.s. deviation of 0.046 Å. In the crystal, very weak C-H⋯O interactions link the molecules into sheets parallel to (101).
A comparative antimicrobial and toxicological study of gold(III) and silver(i) complexes with aromatic nitrogen-containing heterocycles: Synergistic activity and improved selectivity index of Au(III)/Ag(i) complexes mixture
(2016) Savić, Nada; Milivojević D.; Glišić, Biljana; Ilic-Tomic T.; Veselinović J.; Pavic A.; Vasiljevic B.; Nikodinovic-Runic, Jasmina; Djuran, Miloš
© The Royal Society of Chemistry 2016. Five aromatic nitrogen-containing heterocycles, pyridazine (pydz, 1), pyrimidine (pm, 2), pyrazine (pz, 3), quinoxaline (qx, 4) and phenazine (phz, 5) have been used for the synthesis of gold(iii) and silver(i) complexes. In contrast to the mononuclear Au1-5 complexes all having square-planar geometry, the corresponding Ag1-5 complexes have been found to be polynuclear and of different geometries. Complexes Au1-5 and Ag1-5, along with K[AuCl4], AgNO3 and N-heterocyclic ligands used for their synthesis, were evaluated by in vitro antimicrobial studies against a panel of microbial strains that lead to many skin and soft tissue, respiratory, wound and nosocomial infections. All tested complexes exhibited excellent to good antibacterial activity with minimal inhibitory (MIC) values in the range of 2.5 to 100 μg mL-1 against the investigated strains. The complexes were particularly efficient against pathogenic Pseudomonas aeruginosa (MIC = 2.5-30 μg mL-1) and had a marked ability to disrupt clinically relevant biofilms of strains with high inherent resistance to antibiotics. Moreover, the Au1-4 and Ag1-5 complexes exhibited pronounced ability to competitively intercalate double stranded genomic DNA of P. aeruginosa, which was demonstrated by gel electrophoresis techniques and supported by molecular docking into the DNA major groove. Antiproliferative effect on the normal human lung fibroblast cell line MRC5 has also been evaluated in order to determine therapeutic potential of Au1-5 and Ag1-5 complexes. Since the investigated gold(iii) complexes showed much lower negative effects on the viability of the MRC5 cell line than their silver(i) analogues and slightly lower antimicrobial activity against the investigated strains, the combination approach to improve their pharmacological profiles was applied. Synergistic antimicrobial effect and the selectivity index of 10 were achieved for the selected gold(iii)/silver(i) complexes mixtures, as well as higher P. aeruginosa PAO1 biofilm disruption activity, and improved toxicity profile towards zebrafish embryos, in comparison to the single complexes. To the best of our knowledge, this is the first report on synergistic activity of gold(iii)/silver(i) complexes mixtures and it could have an impact on development of new combination therapy methods for the treatment of multi-resistant bacterial infections.
A Comparison Study of Fatigue Behavior of S355J2+N, S690QL and X37CrMoV5-1 Steel
(2022) Milovanović, Vladimir; Arsić, Dušan; Milutinović, Milan; Zivkovic, Miroslav; Topalović, Marko
Steel of the mild-strength S355J2+N steel grade is the most often used steel for manufacturing carrying sections of constructions exposed to fatigue loads. The use of high-strength steels, such as S690QL, allows for the creation of structures that are light and simple to construct. However, increasing the yield strength of high-strength steels does not result in a corresponding increase in fatigue resistance. As a result, using high-strength steels for constructions subjected to fatigue loading can be a major design concern, raising the question of whether high-strength steels should be used at all. Most of the experimental investigations regarding the hot work tool steel X37CrMoV5-1 found in the literature are focused on its machining and wear resistance, with insufficient attention paid to the cyclic loads. This article evaluates the fatigue properties of mild-strength S355J2+N, high-strength S690QL, and X37CrMoV5-1 steel grades. A SHIMADZU servo-hydraulic testing machine is used to perform uniaxial tensile tests under uniaxial fatigue stress-controlled, fully reversed conditions (tensile–compression testing with R = −1 stress ratio) in accordance with EN ISO and ASTM standards. The aim of this paper is to highlight the fatigue characteristics of these three steels that are among the most used in their respective groups. Steel S355J2+N belongs to the group of hot-rolled normalized steels, S690QL belongs to the group of improved (quenched + tempered) steels with increased strength, and X37CrMoV5-1 belongs to the group of high-alloyed tool steels for hot work. This choice was made as the tested steels can be considered typical representatives of their groups. Based on the test results of these three steels, which are organized in S–N curves, the fatigue behavior of the entire mentioned groups of steels can be foreseen.
A comprehensive study into the boltless connections of racking systems
(2020) Vujanac, Rodoljub; Miloradović, Nenad; Vulovic, Snezana; Pavlović A.
© 2020 by the authors. Licensee MDPI, Basel, Switzerland. In practice, structures of pallet racks are characterized by very wide options of beam-to-column connections. The up to date part of the standard Eurocode 3 considers details for the design of connections. However, experimental determination of the joint properties in steel pallet racks is the most reliable process, since it takes into account an inability to develop a general analytical model for the design of these connections. In this paper, a test procedure for the behavior of beam-to-column connections is presented and the results are analyzed according to the procedure defined in the relevant design codes. With aim to avoid expensive experiments to determine structural properties of different types of connections, a polynomial model and a corresponding numerical model were developed to be used for simulating the experiment. After verification, the developed analytical and numerical model can be applied for investigation of various combinations of beam-to-column connections.
A Discrepancy: Calcium Channel Blockers Are Effective for the Treatment of Hypertensive Left Ventricular Hypertrophy but Not as Effective for Prevention of Heart Failure
(2022) Koracévić G.; Perišić, Zoran; Stanojkovic M.; Stojanovic, Maja; Zdravkovic M.; Tomasevic, Miloje; Djordjevic, Dragan; Mladenovic, Katarina; Koracévic M.; Trkulja J.
Arterial hypertension (HTN) is important due to its high prevalence, morbidity, and mortality rates. Calcium channel blockers (CCBs) are the first-line antihypertensive drugs. HTN can lead to heart failure (HF) by causing hypertensive left ventricular hypertrophy (HTN LVH). CCBs are recommended for the treatment of HTN LVH. The aim of this study was to analyze the status of CCBs regarding (1) HTN LVH treatment and (2) capability to prevent HTN-induced HF in the guidelines. For this narrative review, the following databases were searched: Medline, Scopus, Science Direct, Springer, SAGE, Wiley, Oxford Journals, Cambridge, and Google Scholar. CCBs are effective antihypertensive drugs and a very good therapeutic option for HTN LVH as they can cause reverse LVH remodeling. Consequently, we may expect that CCBs would prevent HF. However, evidence suggests that CCBs confer less protection from HF than other first-line antihypertensive drugs. A negative inotropic action of nondihydropyridine CCBs may contribute to suboptimal protection against HF. This discrepancy is clinically relevant because CCBs are in one of the two recommended (single pill) combinations for the initial treatment of HTN. LVH is a strong risk factor for HF in HTN patients. When LVH arises, the risk of HF increases dramatically. CCBs are inferior to renin-angiotensin-aldosterone system blockers but still very effective in bringing about regression of HTN LVH; consequently, CCBs are expected to protect from HF. On the contrary, CCBs protect from HF less effectively than other first-line antihypertensive drugs. This discrepancy needs to be investigated further to improve clinical practice.
A framework for technology enhanced education in orthopaedics: Knee surgery case study
(2017) Devedzic G.; Petrovic Savic, Suzana; Matic, Aleksandar; Ristic, Branko; Devedzic, Vladan; Asgharpour Z.; Cukovic, Sasa
© Springer Nature Singapore Pte Ltd. 2018. The paper presents a framework for technology enhanced education (TEE) in orthopaedics aimed at employment of ubiquitous information and communication technology (ICT) and digital technologies in order to compensate for an unaffordable learning environment. On the other side, the concept involves both (bio)engineers, ICT specialists, and orthopaedic surgeons in an interprofessional collaboration, leveraging multidisciplinary approaches to improve the quality of clinical-oriented education. Preliminary results indicate increased motivation and satisfaction of both the learners and educators.
A Microfludic Platform as An in Vitro Model for Biomedical Experimentation - A Cell Migration Study
(2021) Milivojević, Nevena; Caballero D.; Carvalho, Mariana; Kokanovic, Mihajlo; Živanović, Marko; Filipovic, Nenad; Reis, Rui L.; Oliveira, Joaquim Miguel
Preclinical experimentation demands for highly reliable and physiologically-relevant systems capable of recapitulating the complex human physiology. Further technological advances are in great need for improving our understanding about critical biological processes involved in tissue development or cancer progression, and for the discovery and screening of novel pharmacological drugs. Traditional in vitro models, albeit widely employed, fail to reproduce the complexity of the native scenario. Similarly, in vivo animal models poorly mimic the human condition and they are ethically questionable. During the last two decades, a new paradigm in preclinical modelling has emerged aiming to solve the limitations of the previous methods. The combination of advanced tissue engineering, cell biology and nanotechnology, has resulted in the development of cutting-edge microfluidics-based models with an unprecedented ability to recreate the native habitat of cells within a microengineered chip. Among the diverse variety of micro- and bio- fabrication techniques, UV-photolithography and soft lithography are considered the gold-standard methods for the fabrication of microfluidic chips to their simplicity, versatility, and rapid prototyping. In this paper, we describe a protocol for the fabrication of a microfluidic chip by UV-photolithography and replica molding, and an example of its use in cell migration assays.
A mild and efficient procedure for alkenols oxyselenocyclization by using ionic liquids
(2019) Kostic, Marina; Verdía P.; Fernández-Stefanuto V.; Puchta, Ralph; Tojo, Emilia
© 2019 John Wiley & Sons, Ltd. A mild and efficient procedure for the oxyselenocyclization of unsaturated alcohols by treatment with phenylselenyl chloride using ionic liquids as solvents/catalyzers has been developed. The reaction proceeds instantaneously under mild conditions with absolute regioselectivity, using primary, secondary, tertiary, and aromatic alcohols, as well as monosubstituted, disubstituted, and trisubstituted alkenols. This procedure provides a new method for the synthesis of substituted tetrahydrofurans and tetrahydropyrans ethers, the precursors of many biologically active metabolites, avoiding the use of toxic and corrosive catalysts. There are no previous reports of selenium-mediated cyclofuncionalization reactions in ionic liquids. Taking into the account the good results obtained with [MMIM][MSO 4 ], its ease preparation, low viscosity, low price, and its capacity to be recovered and reused, it was selected as the solvent/catalyzer. Quantum-chemical calculations (MP2(fc)/6-311 + G**//B3LYP/6-311 + G**) has shown that the intramolecular cyclization is promoted by the hydrogen bond formed between the ionic liquid anion and the hydroxyl group of the alkenol.
A Multiparametric Approach to Cerium Oxide Nanoparticle Toxicity Assessment in Non-Biting Midges
(2020) Savić Zdravković, Dimitrija; Milošević D.; Uluer E.; Duran H.; Matić, Sanja; Stanić S.; Vidmar, Janja; Scancar J.; Dikić D.; Jovanović, Boris
© 2019 SETAC Cerium oxide nanoparticles (CeO2 NPs) are included in the Organisation for Economic Co-operation and Development (OECD) priority list of engineered nanomaterials for assessment of their environmental impact. The present study was carried out to assess the CeO2 NP toxicity to the freshwater midge Chironomus riparius larvae at concentrations of 2.5, 25, 250, and 2500 mg of CeO2 NP/kg of sediment. Experiments were designed to assess the prolonged exposure of midges to CeO2 NPs while adhering to OECD test guideline 218. The following parameters were investigated: CeO2 NP uptake by larvae, oxidative stress parameters, in vivo genotoxic effects, and life trait parameters. Inductively coupled plasma–mass spectrometry analysis showed a significant positive correlation between the concentration of CeO2 NPs in the sediment and its uptake by the larvae. No significant mortality was observed in C. riparius, and oxidative stress was not detected. The only significantly induced sublethal effect was genotoxicity, which began to manifest at a lowest-observed-effect concentration of 25 mg kg–1 of sediment and progressively increased at higher concentrations. Our results indicate that exposure to CeO2 NP–contaminated freshwater sediments does not pose a risk to chironomids at environmentally realistic concentrations. However, the significant accumulation of CeO2 NPs by chironomid larvae may pose a risk through trophic transfer to organisms further up the food chain. Environ Toxicol Chem 2019;39:131–140. © 2019 SETAC.
A new class of half-sandwich ruthenium complexes containing Biginelli hybrids: anticancer and anti-SARS-CoV-2 activities
(2022) Janković, Nenad; Milović E.; Jovanovic, Jelena; Marković, Zoran; Vranes, Milan; Stanojkovic, Tatjana; Matic, Ivana; Djordjic Crnogorac, Marija; Klisuric, Olivera; Cvetinov, Miroslav; Abbas Bukhari S.
In order to discover new dual-active agents, a series of novel Biginelli hybrids (tetrahydropyrimidines) and their ruthenium(II) complexes were synthesized. Newly synthesized compounds were characterized by IR, NMR, and X-ray techniques and investigated for their cytotoxic effect on human cancer cell lines HeLa, LS174, A549, A375, K562 and normal fibroblasts (MRC-5). For further examination of the cytotoxic mechanisms of novel complexes, two of them were chosen for analyzing their effects on the distribution of HeLa cells in the cell cycle phases. The results of the flow cytometry analysis suggest that the proportion of cells in G2/M phase was decreased following the increase of subG1 phase in all treatments. These results confirmed that cells treated with 5b and 5c were induced to undergo apoptotic death. The ruthenium complexes 5a-5d show significant inhibitory potency against SARS-CoV-2 Mpro. Therefore, molecule 5b has significance, while 5e possesses the lowest values of ΔGbind and Ki, which are comparable to cinanserin, and hydroxychloroquine. In addition, achieved results will open a new avenue in drug design for more research on the possible therapeutic applications of dual-active Biginelli-based drugs (anticancer-antiviral). Dual-active drugs based on the hybridization concept “one drug curing two diseases” could be a successful tactic in healing patients who have cancer and the virus SARS-CoV-2 at the same time.
A new efficient domino approach for the synthesis of pyrazolyl-phthalazine-diones. Antiradical activity of novel phenolic products
(2018) Simijonović, Dušica; Petrović, Zorica; Milovanović, Vesna; Petrović, Vladimir; Bogdanovic, Goran A.
© 2018 The Royal Society of Chemistry. Pyrazolyl-phthalazine-dione derivatives (PPDs) were synthetized in the ionic liquid catalyzed one-pot multicomponent reaction of acetylacetone, 2,3-dihydrophthalazine-1,4-dione, and different aldehydes in moderate to good yields. Six new PPDs were obtained, and the crystal structure of 2-acetyl-1-(4-fluorophenyl)-3-methyl-1H-pyrazolo[1,2-b]phthalazine-5,10-dione (PPD-4) was determined. The most interesting structural features of the novel PPD-4 is the formation of a rather short intermolecular distance between the F atom of one molecule and the midpoint of the neighbouring six-membered heterocyclic ring. This interaction arranges all molecules into parallel supramolecular chains. UV-Vis spectra of all PPDs were acquired and compared to the simulated ones obtained with TD-DFT. All synthetized compounds were subjected to evaluation of their in vitro antioxidative activity using a stable DPPH radical. It was shown that PPD-7, with a catechol motive, is the most active antioxidant, while PPD-9, with two neighbouring methoxy groups to the phenolic OH, exerted a somewhat lower, but significant antioxidative potential. The results of DFT thermodynamical study are in agreement with experimental findings that PPD-7 and PPD-9 should be considered as powerful radical scavengers. In addition, the obtained theoretical results (bond dissociation and proton abstraction energies) specify SPLET as a prevailing radical scavenging mechanism in polar solvents, and HAT in solvents with lower polarity. On the other hand, the obtained reaction enthalpies for inactivation of free radicals suggest competition between HAT and SPLET mechanisms, except in the case of the OH radical in polar solvents, where HAT is labeled as prefered.
A nonparametric approach in quantifying species richness of Lumbricidae in East Serbia, Balkan Peninsula
(2017) Stojanovic, Mirjana; Sekulić, Jovana; Trakić, Tanja
© TÜBİTAK. The concept of species richness is currently the most basic and most often used parameter in quantitative assessments of biodiversity. The species richness of Lumbricidae was investigated in East Serbia, one of the highly complex areas in the eastern and central part of the Balkan Peninsula. Our database included 2615 individuals from a total of 54 species. Quantification of species richness was done by using the observed number of species and richness estimators. A nonparametric approach was used to evaluate the performance of various estimation techniques: Chao 2, Jackknife 2, and Bootstrap. However, only Chao 2 reached the asymptote, maintaining values of 77 until the end of the curve. A total of 70.12% of the estimated number of Lumbricidae living in East Serbia were detected in our field study and we should expect that 23 lumbricid taxa will be added to the inventory in the future. The sampling effort needed to find additional species undetected during the sampling is 214 individuals. Chao 2 generally outperforms other estimators since it attains near-asymptotic stability and, therefore, more accurate prediction of earthworm species richness.
A novel approach to process improvement in small and medium manufacturing enterprises
(2014) Tadić, Danijela; Misita, Mirjana; Milanović D.; Djukic, Tijana; Senussi G.
Continuous business process improvement is a well-known strategy referred to as the Japanese approach to industrial production. Nowadays, it presents one of the basic requirements set by the ISO 9004:2000 standard. A new fuzzy model based on the Ishikawa diagram is proposed, whereby the rank of business losses of the main process at the manufacturing company level is determined, respecting the values of identified causes that lead to the formation of business losses, as well as their relative importance. In this article, it is assumed that the relative importance and values of causes are determined by descriptive linguistic expressions. The linguistic expressions are obtained by the fuzzy rating of a management team. The proposed algorithm determines the business losses with the highest possibility of occurrence and calculates the degrees of beliefs that some business losses are more likely to happen than the others. Real-life industrial data on small and medium companies operating in central Serbia and numerical examples are given to illustrate the method. © IMechE 2013.
A novel framework for fluid/structure interaction in rapid subjectspecific simulations of blood flow in coronary artery bifurcations
(2014) Blagojevic, Milan; Aleksandar, Nikolic; Zivkovic, Miroslav; Zivkovic, Milorad; Stankovic, Goran
Background/Aim. Practical difficulties, particularly long model development time, have limited the types and applicability of computational fluid dynamics simulations in numerical modeling of blood flow in serial manner. In these simulations, the most revealing flow parameters are the endothelial shear stress distribution and oscillatory shear index. The aim of this study was analyze their role in the diagnosis of the occurrence and prognosis of plaque development in coronary artery bifurcations. Methods. We developed a novel modeling technique for rapid cardiovascular hemodynamic simulations taking into account interactions between fluid domain (blood) and solid domain (artery wall). Two numerical models that represent the observed subdomains of an arbitrary patient-specific coronary artery bifurcation were created using multi-slice computed tomography (MSCT) coronagraphy and ultrasound measurements of blood velocity. Coronary flow using an in-house finite element solver PAK-FS was solved. Results. Overall behavior of coronary artery bifurcation during one cardiac cycle is described by: velocity, pressure, endothelial shear stress, oscillatory shear index, stress in arterial wall and nodal displacements. The places where (a) endothelial shear stress is less than 1.5, and (b) oscillatory shear index is very small (close or equal to 0) are prone to plaque genesis. Conclusion. Finite element simulation of fluid-structure interaction was used to investigate patient-specific flow dynamics and wall mechanics at coronary artery bifurcations. Simulation model revealed that lateral walls of the main branch and lateral walls distal to the carina are exposed to low endothelial shear stress which is a predilection site for development of atherosclerosis. This conclusion is confirmed by the low values of oscillatory shear index in those places.

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