98 results on '"Gligorijević N"'
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2. The influence of the tooth preparation finish line position on the expression of matrix metalloproteinase-9 and the presence of periodontopathogens in the gingival crevicular fluid.
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JOVANOVIĆ, M., KOSTIĆ, M., ĐORĐEVIĆ, N. S., ILIĆ, A., TOMIĆ, U., NIKOLIĆ, N., KESIĆ, L. J., GLIGORIJEVIĆ, N., IGIĆ, M., JOVANOVIĆ, R., ĐERLEK, A., STOJANOVIĆ, S., and MILAŠIN, J.
- Abstract
OBJECTIVE: The objective of the study was to determine the concentration of matrix metalloproteinase 9 (MMP-9) and changes in the presence of periodontopathogens in the gingival crevicular fluid before and after tooth preparation with the subgingival and equigingival finish line position. PATIENTS AND METHODS: The clinical prospective study included 20 subjects with an indication for upper canine preparation, with the subgingival (group 1) and equigingival finish line (group 2). Samples were taken in four observation intervals: 5 minutes before (control samples), as well as 15 minutes, 24 and 72 hours after tooth preparation (experimental samples). Measurement of MMP-9 was done using Enzyme-linked Immunosorbent Assay (ELISA). The presence of bacteria in the gingival fluid was proven by the Polymerase chain reaction (PCR) analysis. RESULTS: The MMP-9 values did not differ statistically significantly between the groups (p=0.524). The MMP-9 values showed a statistically significant difference in the given observation period (p<0.001) with a significant linear increase in values (p<0.001). A significant quadratic trend recorded a decrease in the MMP-9 values 15 minutes after preparation, and an increase 24 hours after preparation, without a significant difference in the interaction between groups (p=0.392). After preparation, a significant difference in the presence of periodontopathogens was confirmed, i.e., a decrease in the presence of Prevotella intermedia (p=0.025) and Tannerella forsythia (p=0.016) in group 1, and an increase in the presence of Aggregatibacter actinomycetemcomitans in both groups (p=0.029, p=0.026). CONCLUSIONS: The study is a good basis for determining the influence of tooth preparation on gingival inflammation, with therapeutic (choice of preparation technique) and preventive significance regarding the protection of the periodontal tissue from possible iatrogenic damage. [ABSTRACT FROM AUTHOR]
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- 2023
3. Interaction between fibrinogen and insulin-like growth factor-binding protein-1 in human plasma under physiological conditions
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Gligorijević, N. and Nedić, O.
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- 2016
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4. Examination of correlation of levels of alveolar bone loss in interdental and interradicular space using radiographic analysis
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Pejčić Ana S., Kostić Milena M., Obradović Radmila R., Stanković Ivana V., Minić Ivan Z., Igić Marko A., and Gligorijević Nikola R.
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periodontitis ,tooth furcation ,alveolar bone loss ,diagnosis ,therapy ,Dentistry ,RK1-715 - Abstract
Introduction: One of the consequences of the presence of periodontitis is the loss of alveolar bone in the interdental and interradicular space. Bone loss is very important for assessing the severity of the disease and applying therapeutic procedures. Aim: The objective was to determine and compare the loss of interdental and interradicular alveolar bone using radiographic analysis. Material and methods: 100 patients, aged 40 to 60 years, with chronic periodontitis and involvement of grade III and IV furcations in mandibular molars were examined. After orthopantomographic imaging, morphological measurements of mesial and distal interdental bone loss were performed, as well as the measurements of interradicular space. Then, their interrelationship was analyzed. Results: The mean value of mesial interdental bone loss was 5.90 ± 2.4mm, and the mean value of distal was 6.1 ± 6.1mm, while the mean value of interradicular bone loss was 3.55 ± 5.1mm. The correlation between interradicular and interdental bone loss was statistically significant (p
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- 2023
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5. Analysis of four circulating complexes of insulin-like growth factor binding proteins in human blood during aging
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Nedić, O., primary, Šunderić, M., additional, Gligorijević, N., additional, Malenković, V., additional, and Miljuš, G., additional
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- 2017
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6. P2.14-50 Low Temperature Plasma Needle Induces Cell Cycle Arrest of Epithelial Lung Cancer Cells in Vitro via a p21-Dependent Pathway
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Cavic, M., Selakovic, N., Gligorijevic, N., Puac, N., Malovic, G., Radulovic, S., and Petrovic, Z.
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- 2019
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7. Anthropometric parameters and aesthetics in the making of fixed prosthodontic restaurations: Part 2
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Kostić Milena M., Igić Marko A., Gligorijević Nikola R., Anđelković Maja Z., Jovanović Marija G., Pejčić Ana S., and Burić Kristina N.
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aesthetics ,gingiva ,lip line ,Dentistry ,RK1-715 - Abstract
Introduction: The role of aesthetic dentistry in the field of fixed dental prosthetics is to redesign the smile, which means not only the treatment on the teeth, but also the treatment of the surrounding soft tissues. Successful therapy can be achieved by establishing the harmony between the static (teeth, gingiva) and dynamic factors (lips, cheeks, mimic muscles) at rest and when performing various functions of the orofacial system. The aim: of the study was to analyze the parameters of the oral soft tissues (gingival health, gingival height, gingival zeniths, lip line and symmetry and balance of the dentition) that affect the aesthetics of fixed prosthodontic restorations. Literature data and clinical experience were used. Conclusion: Adherence to the described parameters is of great importance in the development of aesthetic and functional fixed prosthetic restoration.
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- 2022
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8. Comparison of the morphological parameters of the face in a population with a full dental arch
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Kostić Milena M., Igić Marko A., Đerlek Amar M., Gligorijević Nikola R., Jovanović Marija G., Burić Kristina N., and Anđelković-Apostolović Marija R.
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face index ,vertical and horizontal face parameters ,Dentistry ,RK1-715 - Abstract
Introduction: The analysis of facial parameters in young people with a full dental arch is an assessment of the representation of certain anthropological features in the Serbian geographical area, but also a starting point for their reconstruction after tooth loss in order to achieve the maximum therapeutic and aesthetic effect. Aim: The aim of the work was to measure and compare facial parameters among respondents with a complete dental arch. Material and methods: 91 dental students participated in the research, 32 (35.2%) male and 59 (64.8%) female. The average age of the respondents was 22.16±1.53 years. The length and width of the face were measured, as well as the vertical and horizontal parameters, and the facial index was calculated. Results: Men had a significantly longer (Z=4.567; p
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- 2022
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9. Physicochemical characterisation of dihydro-alpha-lipoic acid interaction with human serum albumin by multi-spectroscopic and molecular modelling approaches
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Gligorijević Nikola, Šukalović Vladimir, Minić Simeon, Miljuš Goran, Nedić Olgica, and Penezić Ana
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spectral analysis ,molecular docking ,protein-ligand interaction ,protein stability ,protein structure ,Chemistry ,QD1-999 - Abstract
The binding of a popular food supplement and well-known antioxidant, dihydro-alpha-lipoic acid (DHLA) to human serum albumin (HSA) was characterised. The binding was monitored by several spectroscopic methods together with the molecular docking approach. HSA was able to bind DHLA with moderate affinity, 1.00±0.05×104 M-1. Spectroscopic data demonstrated that the preferential binding site for DHLA on HSA is IIA (Sudlow I). Both experimental and molecular docking analysis identified electrostatic (salt bridges) and hydrogen bonds as the key interactions involved in DHLA binding to HSA. Molecular docking confirmed that the Sudlow I site could accommodate DHLA and that the ligand is bound to the protein in a specific conformation. The molecular dynamic simulation showed that the formed complex is stable. Binding of DHLA does not affect the structure of the protein, but it thermally stabilises HSA. Bound DHLA had no effect on the susceptibility of HSA to trypsin digestion. Since DHLA is a commonly used food supplement, knowledge of its pharmacokinetics and pharmacodynamic properties in an organism is very important. This study further expands it by providing a detailed analysis of its interaction with HSA, the primary drug transporter in the circulation.
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- 2021
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10. Properties and applications of dental polyamides
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Gligorijević Nikola R., Igić Marko A., Kostić Milena M., and Pejčić Ana S.
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dentures ,polyamides ,Dentistry ,RK1-715 - Abstract
Introduction: By examining numerous thermoplastic and flexible materials that would aesthetically and functionally surpass acrylates used for the production of dental prostheses, polyamides were discovered as materials with great potential application in prosthodontics. The aim of this study was to describe polyamide materials used for the production of partial dentures. Material and methods: The main methodological approach of this study was a systematic search of the literature in two electronic databases: Google Scholar and PubMed using predefined keyword combinations. Results: The advantage of polyamide dentures is the comfort and ease of accommodation of the patient, with preserved optimal mechanical and physical properties. The dentures are flexible but rigid enough to be resistant to shock and fractures. Due to their low specific weight, polyamide dentures are light, extremely thin and do not interrupt patient speech. Excellent aesthetics are provided by a high choice of working colors and high translucency of the material, which ensures that the soft tissue that's covered by the denture base or clasp is seen through the prosthesis and gives it a more natural appearance in the patient's mouth. Conslusion: Polyamides, unlike acrylates, do not contain residual monomers, so they have an greater degree of biocompatibility. They can be used for the production of both complete and partial dentures, in combination with a Cr-Co skeleton, or crowns and bridges.
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- 2020
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11. Legalization of cannabis in Canada
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Gligorijević Nemanja
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legalization ,cannabis ,marijuana ,canada ,Criminal law and procedure ,K5000-5582 ,Social pathology. Social and public welfare. Criminology ,HV1-9960 - Abstract
This article is about legalization of cannabis in Canada. It starts with marijuana first being criminalized almost hundred years ago. Article disribes the changes in attitudes towards cannabis in the 70's that followed the Hippie movement in the 60's, status quo for 30 years, legalization of cannabis for medical purposes in the dawn of the 21st centery. Described are arguments used by Canadian politician during the debate about the controversial bill C-45 that eventually became The Cannabis Act, which became a specific piece of legislation, with a devoted section prescribing criminal sanctions. Commities of experts have spent many hours debating, experimenting on pros and cons of the issue. The Cannabis Act sets strict rules on distribution to minors and manufacturing without a licence. By legalizing cannabis Canada violates many international trieties, not facing any consequences for those violations, making legalisation in other countries to be considered as a possibility. Canada did not solve cannabis black market by making cannabis legal. Legalization have not had a cataclismic effect on Canadian population. Follow up studies are to be done by the Government in 2021.
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- 2020
12. Effect of cyclic loads on structural damage of rocket propellant grain
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Gligorijević Nikola, Rodić Vesna, Pavković Bojan, Bogdanov Jovica, Živković Saša, and Bajić Zoran
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rocket motor ,propellant grain ,mechanical properties ,structural analysis ,cumulative damage ,service life ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
Rocket motor propellant grain, cast or bonded into the motor chamber or solid coating, is exposed to various loads during its service life. Rocket propellant is a viscoelastic material, whose mechanical properties strongly depend on temperature and strain rate. Application of cyclic loads, primarily thermal, onto a rocket motor on the field stock, may cause an undesirable mechanical damage of the grain. Over time, after long storage, it may grow up and lead to the grain failure. One of the ways for evaluation of this phenomenon is to determine a cumulative damage law. In this example, this law has been evaluated for hydroxy terminated polybutadiene (HTPB) composite rocket propellant by exposing a number of specimens to different long term stress levels. Using this law, it is possible to calculate a probability of failure and time distribution of the structural reliability of the grain in order to determine the useful life. Besides, the analysis has shown that there is a possible correlation between tensile strength of the propellant and the cumulative damage law. This fact can be used instead of carrying a longterm experiment for the exact determination of the law.
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- 2019
13. Quantitation of the active alpha-2-macroglobulin by trypsin protease zymography
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Gligorijević Nikola, Šunderić Miloš, Vilotić Aleksandra, Baralić Marko, and Nedić Olgica
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alpha-2-macroglobulin ,functional assay ,electrophoresis ,Chemistry ,QD1-999 - Abstract
A simple and reliable method for the determination of the concentration and function of alpha-2-macroglobulin (α2M) by zymography was developed. The method is based on the covalent binding of α2M and trypsin followed by non-reducing PAGE and zymography with gelatine incorporated in the electrophoretic gel. The results showed that α2M binds trypsin in a concentration-dependent manner exhibiting a linear relation. The sensitivity of the method is 125 nM and the intra-assay coefficient of variation 4.2 %. Freezing of α2M induces its partial denaturation, which could be seen as the reduction in the amount of functional molecule and its reactivity with trypsin. The reported method enables measurement of α2M taking into consideration both its quantity and function, stressing the importance of the determination of the amount of physiologically active molecules and not just their presence in the sample. The method was further confirmed using α2M from patients with end-stage renal disease who are known to be under increased oxidative stress and inflammation, which are expected to modify the structure of proteins. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 173042]
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- 2019
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14. Early use of partial acrylic denture obturator in the postoperative treatment of bone defects after marsupialisation of large jaw cysts
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Jovanović Marija, Stojanović Simona, Todorović Kosta, Obradović Radmila, Igić Marko, Stojković Branislava, Gligorijević Nikola, Spasić Milan, and Jovanović Goran
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cysts ,marsupialisation ,opturator prosthesis ,wound healing ,Dentistry ,RK1-715 - Abstract
Introduction: After marsupialisation of large jaw cysts, there comes to the formation of bone defects which do not guarantee the stability of the blood clot and therefore are filled with iodine gauze. Any replacement of iodine gauze, toilet of the wound, causes minor or major bleeding, which slows wound epithelialisation and organization. Therefore, making the partial acrylic denture obturator is recommended to be done a few weeks after the surgery. Case report: This work presents two patients who had partial acrylic denture obturator made on the tenth day after the surgery. This allowed significantly easier toilet of the wounds, faster epithelialization and organization, and thus faster bone healing. Conclusion: Restored function of chewing, swallowing and speech, as well as the aesthetic appearance suggest that early use of acrylic obturator prosthesis is very significant.
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- 2019
15. Effects of water boiling, microwave, and water bath post-polymerization on mechanical properties of acrylic denture resins
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Kostić Milena, Nikolić Ljubiša, Nikolić Vesna, Petković Dušan, Igić Marko, Krunić Nebojša, Manić Miodrag, Gligorijević Nikola, and Radenković Goran
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acrylate ,flexural strength ,flexural modulus ,fracture risk ,Chemical technology ,TP1-1185 - Abstract
Acrylic restorations in the mouth are exposed to strong occlusal forces. Their mechanical properties depend on the type and method of their polymerization. The aim of this study is a comparative analysis of mechanical properties (flexural strength and modulus of elasticity) of acrylic materials before and after the post-polymerization treatments (water boiling, microwave irradiation and water storage). The study included denture base resins, as well as an acrylate for orthodontic appliances impregnated with aesthetic beads. Flexural strength, modulus of elasticity and the deflection were measured immediately after polymerization, after a hot and microwave post-polymerization and after immersion in a water bath at the temperature of 37°C. The applied post-polymerization methods resulted in an increase in flexural strength and modulus of elasticity relative to the initial values for all tested materials. Being aware of the reduction in fracture risk of dental prosthesis after a proposed post-polymerization procedure, it could be used in all clinical situations where there is an increased risk of damage to dentures.
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- 2018
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16. Denture base resins biocompatibility testing in vivo
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Kostić Milena, Najman Stevo, Mihailović Dragan, Krunić Nebojša, Gligorijević Nikola, Gligorijević Jasmina, Igić Marko, and Marinković Nikola
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dentures ,acrylates ,biocompatible materials ,rats ,Medicine (General) ,R5-920 - Abstract
Background/Aim. The wearing of acrylic dentures is the cause of the inflammatory reaction of the oral mucosa. The aim of this study was to investigate the response of rat tissues to subcutaneous and intramuscular implantation of different acrylic samples, by histopathological analysis of the tissue. Methods. The study included two samples of hard and three samples of soft acrylic resins (heat and cold polymerized), that were subcutaneously and intramuscularly implanted in rats tissues. Implantation tests were designed to test the biological response of the surrounding tissue to the tested materials after their application for the period of two weeks and the period of four months. Results. After two weeks, regardless of the type of implantation, histopathological analysis showed an acute inflammatory response. There was an intense hyperplasia of inflammatory cells, multiplication of connective tissue as well as formation of many new blood vessels. The highest level of inflammatory changes was observed after the application of cold-polymerized resins. A lower intensity of inflammation in the case of heat polymerised resin was the result of its more complete polymerization. After the second observation period, fibrotic capsules were formed around the implanted samples indicating a chronic course of the inflammatory process. Less visible signs of inflammation and chronicity of the processes indicate that with time, i.e. with the length of the observation period, reduces inflammation. Conclusion. The subcutaneous and intramuscular implantation of acrylic resins material samples led to inflammatory response whose intensity was decreased over time. Heat polymerized resin was a biologically more acceptable in comparison to the cold polymerized acrylates.
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- 2018
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17. State of the propulsive-group development for enhanced anti-armored guided missile
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Marjanović Goran, Kozomara Stevan, Stojković Srđan, Gligorijević Nikola, Živković Saša, and Pavković Bojan
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anti-armor rocket ,rocket motor ,propulsive group ,starting (booster) motor ,marching (sustainer) motor ,propellant grain ,thrust ,pressure ,range ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
The main propulsive group of anti-armor guided missile is reinforced by additional propulsive group with the aim to increase the range. Final concept of the propulsion has been adopted after consideration of several proposed solutions. Two additional motors are made and they are currently under development. The first results were obtained, and the additional motors at this stage are refined through the static tests as well as through the correction of the composition and the design of the propellant grains. An overview of the common procedure is described on the way to winning the final solution for rocket propulsion.
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- 2018
18. Influence of the ignition mixture particle size on rocket motor igniter pressure gradient
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Gligorijević Nikola, Nešić Jovica, Bogdanov Jovica, Pavković Bojan, Živković Saša, and Tanaskovski Bojan
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rocket motor ,ignition ,igniter ,pressure ,pressure gradient ,ignition mixture ,granulation ,tablets ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
The paper discusses the influence of ignition mixture granulation onto the regime of rocket motor ignition. Igniter tests were performed in manometric bomb and pressure distribution was measured. In each test different granulations of the same mixture in powder form were tested. After that, two different ignition mixture compositions in the form of pressed tablets were tested. Total masses of ignition mixtures were equal in all the tests. In the first series of the igniter tests, very carefully chosen different granulation of the powder was used in each test, with the particles in a narrow range. From one to another test, only the granulation of the mixture was changed. The purpose was to determine if there exists an influence of the mixture granulation onto the pressure gradient and thus also onto the regime of the rocket motor ignition. It turned out, surprisingly, that there were no visible differences in the regimes of pressure increase due to the different granulation of the ignition mixtures. In another series of tests the mixture was prepared in the form of pressed tablets, with various sizes from test to test. Two different mixtures were tested, and the mass of each single charge of the igniter was the same as in the first series of tests. It is shown that the form of the pressed tablets, as well as their composition, may considerably affect the mode of rocket motor ignition.
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- 2018
19. Antimicrobial properties of acrylic resins for dentures impregnated with silver nanoparticles
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Gligorijević Nikola, Kostić Milena, Tačić Ana, Nikolić Ljubiša, and Nikolić Vesna
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silver nanoparticles ,acrylates ,antimicrobial activity ,Dentistry ,RK1-715 - Abstract
Introduction. Porosity and surface adherence of acrylates make them collectors of infectious content from the mouth. This applies particularly to cold-curable acrylates, whose structure is less compact. The aim of this study was to investigate the antimicrobial effects of cold polymerized dental acrylics after impregnation with silver nanoparticles. Material and Methods. Different concentrations (2%, 5% and 10%) of silver nanoparticles were added to the polymer components (powder) of cold polymerizing acrylate, after which disk-shaped samples, 10 mm, in diameter, were made. A disk of silver nanoparticles was used as a control for our study. Antimicrobial activity was investigated using the disc diffusion method on the two most common oral cavity infecting agents - Gram positive bacterium, Staphylococcus aureus ATCC 25923, and fungus Candida albicans ATCC 2091. The results have shown that the control sample as well as the samples of silver impregnated acrylics resins exhibit antibacterial activity. The growth zone inhibition of Staphylococcus aureus in the culture medium is proportional to the concentration of silver nanoparticles in the cold curing acrylic resin. On the other hand, the test samples did not inhibit the growth of Candida albicans in the medium. Conclusion. Silver nanoparticles in cold curing acrylic resin demonstrated antibacterial activity. Expanding their antimicrobial spectrum of activity and their potential clinical application will be the subject of the future research.
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- 2017
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20. Preliminary research of composite rocket propellants including octogene
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Rodić Vesna, Bogosavljević Marica, Milojković Aleksandar, Brzić Saša, Fidanovski Bojana, and Gligorijević Nikola
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composite rocket propellant ,ammonium perchlorate ,hydroxyterminated polybutadien ,octogen ,titanium (iv) oxide ,ballistic properties ,burning rate ,mechanical characteristics ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
Composite solid propellants based on ammonium perchlorate/hydroxyterminated polybutadiene/isophorone dyisocyanate including different contents of octogene (HMX) have been represented in this paper. The mass of HMX increased in relation to oxidant, with constant bimodal fraction ratio. Combustion of the propellants has been improved by adding of titanium (IV) oxide powder as stabilizer. Parameters of burning rate laws were determined and compared for the propellants of the same total solid phase. Also, the apparent viscosity, uniaxial mechanical characteristic, density and energetic values were determined for the same formulations.
- Published
- 2017
21. Factors affecting job satisfaction among primary and secondary school teachers in the autonomous province of Vojvodina
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Majstorović Nebojša Z., Matanović Jelena M., and Gligorijević Nataša I.
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job satisfaction ,life satisfaction ,teachers ,school climate ,health ,Theory and practice of education ,LB5-3640 - Abstract
The study presented in this paper analyses the impact of the individual factors of mental and physical health and life satisfaction, as well as the importance of some organizational factors such as the climate in schools, the composition of classes in the case of class teachers, and certain demographic characteristics on primary and secondary school teachers' job satisfaction. The data were collected from a convenience sample of 176 teachers of primary and secondary schools in Serbia's autonomous province of Vojvodina, of different ages, genders, and years of service. The principal results indicate that job satisfaction is higher among teachers who perceive the climate in their school as positive, among teachers with higher life satisfaction, and among teachers who are in good health and, most importantly, lacking depressive reactions. When it comes to perceptions of the climate, the best predictor of job satisfaction is the degree of respondents' satisfaction with collaboration with colleagues and with decision making processes. The results also indicate that secondary school teachers report a higher level of overall job satisfaction, specifically, a higher level of satisfaction with school governance, co-workers and communication than primary school teachers. As regards demographic characteristics, the results suggest that there are no significant gender differences in job satisfaction levels and that job satisfaction declines with the number of years of service, with respondents who had between 21 and 30 years of service reporting the lowest levels of job satisfaction, which tended to rise towards the end of the teaching career.
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- 2017
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22. Analysis of viscoelastic behavior of a filled elastomer under action of different loads
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Gligorijević Nikola I., Živković Saša Ž., Kovačević Nenad V., Dimitrijević Nenad P., Pavković Bojan M., Pavić Miloš, and Rodić Vesna Ž.
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composite propellant ,viscoelasticity ,time-temperature shift factor ,ultimate strength ,damage ,probability of failure ,Chemical technology ,TP1-1185 - Abstract
Mechanical properties of viscoelastic filled polymers strongly depend on temperature and strain rate and vary for several orders of magnitude. During service life, a viscoelastic body, especially carboxy-terminated polybutadiene (CTPB) composite solid rocket propellant grain, is subjected to many stress-inducing loads. Its structural integrity analysis (hereafter: “structural analysis”), unlike elastic bodies, is quite complex and sometimes impossible under the action of just a single load. An even greater problem occurs when multiple different types of loads act simultaneously. This study is based on a complete uniaxial mechanical characterization of a viscoelastic CTPB composite rocket propellant, made in MTI- -Belgrade, whose results were used for the analysis of the propellant grain reliability. Through an example, this paper shows a behavior of the viscoelastic propellant grain when it is subjected to extremely different environmental loads at the same time. Similar explicit examples are difficult to found in the literature, except in the form of recommended principles for analysis. It is shown that the tensile strength under the action of fast load due to the pressure may be almost 20 times greater than the tensile strength under the slow temperature load. A probabilistic approach is presented in evaluation the reliability and service life. An example is shown for a rocket propellant grain as a viscoelastic body. The presented principles of the analysis can be applied to any arbitrary viscoelastic body in other areas.
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- 2017
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23. Influence of preparation method on mechanical characteristics of plaster
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Igić Marko, Kostić Milena, Petković Dušan, Gligorijević Nikola, Dačić Stefan, and Stošić Nenad
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plaster ,compressive strength ,Dentistry ,RK1-715 - Abstract
Introduction: Plaster is widely used in dentistry for the production of master casts, as a binder in investment materials and as an auxiliary material in the laboratory stages of denture production. Due to its brittleness, there is a constant need to improve its mechanical properties. In this regard, in the research we started from the assumption that increasing the proportion of powder during the preparation of plaster improves its mechanical properties. The aim of this research wasto determine the significance of the change in the ratio of powder and liquid to the mechanical characteristics of plaster (compressive strength). Material and methods: Three types of plaster were used in the research: type 2, 3 and 4. For each type of plaster, three samples were made with different ratio of powder and amount of water (n = 9). After 24 hours, the samples were analyzed at the Faculty of Mechanical Engineering in Niš, on a universal testing machine. Results: Plaster type 2 showed the lowest values of compressive strength, and higher values of types 3 and 4, regardless of the ratio of plaster powder and water. As the powder content increased, the compressive strength of the samples increased. Conclusion: In order to improve the compressive strength, the proportion of powder in the liquid phase can be increased during the preparation of the material without visible changes in its structure.
- Published
- 2021
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24. Anthropometric parameters and aesthetics in the making of fixed prosthodontic restaurations: Part 1
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Gligorijević Nikola, Igić Marko, Andjelković Maja, Jovanović Marija, Janković Natasa, and Kostić Milena
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anthropometric parameters ,aesthetics ,prosthodontics ,Dentistry ,RK1-715 - Abstract
Introduction: Modern dental procedures, especially those in prosthodontics, restore the functional capacity of the orofacial system and improve the patient's appearance. The modern concept of aesthetic dentistry is the most natural appearance of the teeth, and the success of the therapy is closely connected with the respect of anthropometric parameters and the correct ratio of hard and soft oral tissues. Orofacial elements should not be viewed separately from the composition of the face because they form an inseparable whole with it. The aim of this study was to analyze the parameters of the orofacial system that affect the aesthetics of fixed prosthodontic restorations based on literature data and clinical experience. Conclusion: The beauty of a smile is determined by the shape, color and proportions of the upper front teeth. The harmony in creating a smile is not significantly affected by individual numerical values of tooth width and length, but by their mutual relationship. A beautiful smile implies the convergence of the longitudinal axes of the front teeth in relation to the midline of the dental arch, which progresses from the central incisor to the canine. In addition to these criteria, the visibility of the incisors, the midline of the face and dental arch, interdental points and contacts, incisal free spaces as well as the color of the teeth should be taken into account in order to achieve maximum aesthetic effects.
- Published
- 2021
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25. Reliability of solid rocket propellant grain under simultaneous action of multiple types of loads
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Gligorijević Nikola, Živković Saša, Rodić Vesna, Antonović Saša, Milojković Aleksandar, Pavković Bojan, and Novaković Zoran
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rocket motor ,propellant grain ,composite propellant ,viscoelasticity ,stress ,tensile strength ,damage ,reliability ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
A case-bonded solid propellant rocket grain is subjected to many stress-inducing loads during the service life, due to temperature, extended polymerization, transportation, vibration, acceleration, aerodynamic heating etc. and finally due to the operating pressure in the rocket motor. Composite propellant is a viscoelastic material whose mechanical properties highly depend on temperature and strain rate and sometimes may vary in the range of use of rocket motors for several orders of magnitude. Relationships between stresses and strains are much more complex than for the elastic material. Therefore, the stress and strain analysis and estimation of safety factor under the action of each individual load is quite complex and sometimes impossible. An even greater problem occurs when multiple different types of loads act simultaneously. An extreme case occurs in the moment of rocket motor ignition. Then, the very fast load acts due to the pressure, at which the propellant tensile strength is high. At the same time, the very slow thermal load acts on the grain, and in these conditions the propellant tensile strength is low. The vector addition of the stresses and strains due to different loads is not possible. It is also not possible to define the equivalent or resultant values of tensile strength and allowable strain. The principle of adding the current damage is applied here, similar to the model of cumulative damage. In addition, due to the large variations in mechanical properties of the rocket propellant, it is necessary to apply the methods of mathematical statistics for assessing the propellant grain reliability and service life.
- Published
- 2016
26. Mechanical characterization of composite solid rocket propellant based on hydroxy-terminated polybutadiene
- Author
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Gligorijević Nikola I., Rodić Vesna Ž., Živković Saša Ž., Pavković Bojan M., Nikolić Momčilo M., Kozomara Stevan M., and Subotić Sredoje D.
- Subjects
composite propellant ,viscoelasticity ,mechanical characterization ,tensile strength ,ultimate strain ,time-temperature shift factor ,relaxation modulus ,safety factor ,reduced time ,Chemical technology ,TP1-1185 - Abstract
This paper presents the procedure of uniaxial mechanical characterization of composite solid rocket propellant based on hydroxy-terminated polybutadiene (HTPB), whose mechanical properties strongly depend on temperature, strain rate, natural aging and accumulated damage. A method of processing data is presented in order to determine time-temperature shift factor and master curves for tensile strength, ultimate strain and relaxation modulus, depending on reduced time. Functional dependences of these features represent an input for structural analysis of a rocket motor propellant grain. The effects of natural aging on the mechanical properties are also considered. [Projekat Ministarstva nauke Republike Srbije, br. TR 36050: Research and development of unmanned aircraft in support of traffic infrastructure monitoring]
- Published
- 2016
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27. Thermal and acceleration load analysis of new 122 mm rocket propellant grain
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Gligorijević Nikola, Antonović Saša, Živković Saša, Pavković Bojan, and Rodić Vesna
- Subjects
rocket ,122 mm calibre ,rocket engine ,propellant grain ,thermal load ,acceleration ,viscoelasticity ,structural analysis ,tensile strenght ,damage ,reliability ,finite elements method ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
In order to achieve very strong inter-ballistic requirements, a unusual free standing rocket motor propellant grain was designed, with variable channel diameter. Due to its very high length, it was expected for the grain to be exposed to dangerous combination of different loads during the design phase. Structural analysis of viscoelastic propellant grain is always very complex and it differs substantially from an elastic analysis, because the propellant mechanical properties depend on temperature and strain rate. The most complex case in the analysis occurs when multiple loads operate simultaneously. In this paper, the structural analysis has been done during the initial period of rocket flight, when the grain is under very fast load due to acceleration and at the same time under a slow load due to surface pressure, created as a result of temperature dilatation. In the absence of data on mechanical properties of the new propellant composition, the properties over the whole time-temperature range were estimated comparing by a similar composition that have been completely tested earlier. Using finite element method (ANSYS program) two different design solutions were examined and the more reliable one was adopted.
- Published
- 2016
28. Cast composite solid propellants with different combustion stabilizers
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Rodić Vesna, Dimić Mirjana, Brzić Saša, and Gligorijević Nikola
- Subjects
composite solid propellant ,composite rocket propellant ,cast propellant ,combustion stability ,stabilizers ,aluminium ,zirconium carbide ,titanium oxide ,antimony oxide ,temperature sensitivity ,burning rate ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
The effect of four different compounds as the combustion stabilizers of composite solid propellants based on the AP/HTPB/IPDI has been presented in this paper. Except that, various total solid content, ammonium-perchlorate bimodal and trimodal combination of particle sizes ratio have been made by preparing the eleven formulations. For all of them, the burning rate law's parameters and temperature sensitivity, uniaxial mechanical characteristics, apparent viscosity of uncured propellants and physic-chemical and energetic values have been determined and compared.
- Published
- 2015
29. Mechanical properties of HTPB composite propellants in the initial period of service life
- Author
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Gligorijević Nikola, Živković Saša, Subotić Sredoje, Pavković Bojan, Nikolić Momčilo, Kozomara Stevan, and Rodić Vesna
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composite rocket propellant ,mechanical properties ,aging ,tensile strength ,deformation ,modulus of elasticity ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
Uniaxial tensile tests of different composite solid rocket propellant compositions, based on hydroxyl-terminated polybutadiene (HTPB), have shown that mechanical properties extensively change after curing, up to 100% of their initial values, during the first few months. After that period, they stabilize and start to return slowly in the opposite direction. Careful measurements of these features are necessary in order to control the production quality of the propellant and for a comparison of different propellant compositions or batches. Furthermore, time distributions of the mechanical properties in the initial period after production and short-time aging should not be neglected, because they strongly affect the propellant grain structural analysis and a correct estimation of rocket motor reliability.
- Published
- 2014
30. Solving an irregular burning problem in a small rocket motor
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Gligorijević Nikola, Boulahlib Mohammed Amine, Živković Saša, Subotić Sredoje, Kozomara Stevan, and Nikolić Momčilo
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solid rocket propellant ,double-based propellant ,propellant grain ,erosive burning ,surface burning ,pressure coefficient ,thrust ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
During the design and development of a solid rocket motor, intensive irregular burning appeared in the area of high initial temperatures. The cylindrical propellant grain was designed for approximately neutral burning, with a hollow tube and both burning ends as well as with the outer surface inhibited. A simple grain configuration and a propellant with plateau burning were selected, and the operating pressure of the rocket motor was chosen to be in the area of the plateau. Unfortunately, the special conditions of the gas flow through the propellant grain port, caused by the central tube passing through the grain channel, as well as high propellant temperature sensitivity, led to an increased turbulence and a very strong irregular burning occurrence at high temperatures (+50oC). In these conditions the combustion went out of the plateau regime and the pressure exponent rapidly grew up. The problem was solved without changing the double-based propellant composition. The high burning surface to nozzle throat area ratio was decreased below the critical threshold appearance of irregular burning, without significantly affecting the motor performances. The rocket motor nozzle and the propellant grain were redesigned. Despite the limited possibilities of changing the propellant grain geometry, an uncommon solution was found, opening a part of the inhibitor at the outer surface of the grain.
- Published
- 2014
31. A thin layer chromatographic comparison of raw and soluble starch hydrolysis patterns of some α-amylases from Bacillus sp. isolated in Serbia
- Author
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Gligorijević Nikola, Stevanović Nikola, Lončar Nikola, Baošić Rada, Vujčić Zoran, and Božić Nataša
- Subjects
bacterial amylase ,raw starch digestion ,TLC ,zymogram ,Chemistry ,QD1-999 - Abstract
Several natural isolates of Bacillus strains namely 5B, 12B, 16B, 18 and 24B were grown on two different temperatures in submerged fermentation for the raw-starch-digesting a-amylases production. All strains except Bacillus sp. 18 produced more α-amylase on 37ºC. The hydrolysis of raw corn starch followed same pattern. Efficient hydrolysis was obtained with α-amylases from Bacillus sp. 5B, 12B, 16B and 24B grown on 37ºC and Bacillus sp. 18 grown on 50ºC. Zymography after isoelectric focusing shown that α-amylases were produced in multiple forms, from 2 to 6, depending on the strain when they were growing at 37 ºC, while growing at 50ºC induced only 1 or 2 isoforms. TLC analysis of hydrolysis products of raw corn and soluble starch by α-amylases revealed production of various mixtures of oligosaccharides. In most cases G3 was the most dominant product from soluble starch while G2, G3 and G5 were the main products of raw starch hydrolysis. This indicates that obtained a-amylases can be used for starch liquefying or short-chain-oligosaccharide forming, depending on what type of starch (raw or soluble) was used for the hydrolysis. [Projekat Ministarstva nauke Republike Srbije, br. 172048]
- Published
- 2014
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32. Methodological institutionalism in the context of economic science evolution
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Gligorijević Nemanja J., Pavlović Miloš Lj., and Vujović Tanja M.
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trend of modern science ,institutionalization ,scientific and ideological institutions ,contradictions ,interests ,History of scholarship and learning. The humanities ,AZ20-999 - Abstract
As the achievements of the modern civilization and the result of the dominant trend of modern science, the existing methodological concepts of scientific progress analysis are incomplete and inadequate. Institutionalization of science comes to redefining the hierarchy and heterarchy in the organization of scientific research, which raises the level of cognitive effects from the individual to the collective level, leading to the establishment of a new relationship between the individual, the scientific, and ideological institutions. Contradictions between cognitive status and interests of each of the agents (operative, scientific, and ideological institutions) must be reflected in a scientific paper and thus the overall trend of progress in science. Rationality of an agent is a function that influences cognitive and institutional interests.
- Published
- 2014
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33. Screening Algal and Cyanobacterial Extracts to Identify Potential Substitutes for Fetal Bovine Serum in Cellular Meat Cultivation.
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Sibinčić N, Krstić Ristivojević M, Gligorijević N, Veličković L, Ćulafić K, Jovanović Z, Ivanov A, Tubić L, Vialleix C, Michel T, Srdić Rajić T, Nikolić M, Stojadinović M, and Minić S
- Abstract
Cultured meat technology is a form of cellular agriculture where meat is produced from animal cells grown in a lab, instead of raising and slaughtering animals. This technology relies heavily on fetal bovine serum (FBS) in cell media; hence, production is costly and contributes significantly to ammonia and greenhouse gas emissions. Achieving the successful commercialization of cell-cultured food requires the critical resolution of manufacturing cost and safety concerns. Hence, our research efforts are focused on identifying commercially viable and ecologically sustainable alternatives to FBS. In this study, we evaluated the potential of twenty-six water-based algal and cyanobacterial extracts to stimulate cell growth for meat cultivation under 90% reduced serum conditions. The extracts were compared in viability, proliferation, and Trypan blue exclusion assays. In the first screening phase, the extracts were evaluated in a ZEM2S (zebrafish) cell culture in a 1% FBS regimen. Based on their ability to exhibit protein tolerance or promote cell proliferation, ten extracts were selected and further assayed in a QM7 cell culture. The QM7 cell line (myoblasts from Japanese quail) is highly relevant for meat cultivation because of its ability to differentiate into muscle fibers. Extracts derived from two microalgae species, Arthrospira platensis ( Spirulina ) and Dunaliella tertiolecta , demonstrated the highest tolerance in cell culture, above 10 μg/mL (expressed as total protein concentration). Tolerance at a 100 μg/mL concentration was demonstrated exclusively using an extract of blue spirulina (commercially purified Spirulina ), which supported cell growth through multiple passages.
- Published
- 2024
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34. Phycocyanobilin is a new binding partner of human alpha-2-macroglobulin that protects the protein against oxidative stress.
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Šunderić M, Gligorijević N, Milčić M, Minić S, Nedić O, and Nikolić M
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- Humans, Binding Sites, Molecular Docking Simulation, Molecular Dynamics Simulation, Oxidation-Reduction, Phycobilins metabolism, Phycobilins chemistry, Protein Binding, Protein Conformation, Oxidative Stress drug effects, Phycocyanin chemistry, Phycocyanin metabolism, Pregnancy-Associated alpha 2-Macroglobulins metabolism, Pregnancy-Associated alpha 2-Macroglobulins chemistry
- Abstract
Under simulated physiological conditions, this study investigates the interaction between nutraceutical phycocyanobilin (PCB) and the universal anti-protease protein human alpha-2-macroglobulin (α
2 M). Extensive molecular docking analyses on multiple α2M conformations, spectroscopic techniques, and α2M activity assays were utilized to examine the complex formation. The results revealed that for every protein conformation, two high energy binding sites exist: the first, conformationally independent, at the interface region between two monomer chains and the second, conformationally dependent, in the pocket composed of amino acids from four distinct domains (TED, RBD, CUB, and MG2) of the single protein chain. Spectrofluorimetric measurements indicated a moderate affinity between α2 M and PCB with a moderately high binding constant of 6.3 × 105 M-1 at 25 °C. The binding of PCB to α2 M resulted in minor changes in the secondary structure content of α2 M. Furthermore, PCB protected α2 M from oxidation and preserved its anti-protease activity in the oxidative environment. These findings suggest that PCB binding could indirectly impact the body's response to oxidative stress by influencing α2 M's role in controlling enzyme activity during the inflammatory process.Communicated by Ramaswamy H. Sarma.- Published
- 2024
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35. Narrative Review of the Current and Future Perspectives of Phycobiliproteins' Applications in the Food Industry: From Natural Colors to Alternative Proteins.
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Minić S, Gligorijević N, Veličković L, and Nikolić M
- Subjects
- Food Coloring Agents chemistry, Humans, Phycobiliproteins chemistry, Food Industry methods
- Abstract
Vivid-colored phycobiliproteins (PBPs) have emerging potential as food colors and alternative proteins in the food industry. However, enhancing their application potential requires increasing stability, cost-effective purification processes, and consumer acceptance. This narrative review aimed to highlight information regarding the critical aspects of PBP research that is needed to improve their food industry potential, such as stability, food fortification, development of new PBP-based food products, and cost-effective production. The main results of the literature review show that polysaccharide and protein-based encapsulations significantly improve PBPs' stability. Additionally, while many studies have investigated the ability of PBPs to enhance the techno-functional properties, like viscosity, emulsifying and stabilizing activity, texture, rheology, etc., of widely used food products, highly concentrated PBP food products are still rare. Therefore, much effort should be invested in improving the stability, yield, and sensory characteristics of the PBP-fortified food due to the resulting unpleasant sensory characteristics. Considering that most studies focus on the C-phycocyanin from Spirulina, future studies should concentrate on less explored PBPs from red macroalgae due to their much higher production potential, a critical factor for positioning PBPs as alternative proteins.
- Published
- 2024
- Full Text
- View/download PDF
36. Glycosylation and Characterization of Human Transferrin in an End-Stage Kidney Disease.
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Miljuš G, Penezić A, Pažitná L, Gligorijević N, Baralić M, Vilotić A, Šunderić M, Robajac D, Dobrijević Z, Katrlík J, and Nedić O
- Subjects
- Humans, Glycosylation, Male, Female, Middle Aged, Peritoneal Dialysis, Aged, Adult, Iron metabolism, Transferrin metabolism, Kidney Failure, Chronic therapy, Kidney Failure, Chronic metabolism, Receptors, Transferrin metabolism
- Abstract
Chronic kidney disease (CKD) is a global health concern affecting approximately one billion individuals worldwide. End-stage kidney disease (ESKD), the most severe form of CKD, is often accompanied by anemia. Peritoneal dialysis (PD), a common treatment for ESKD, utilizes the peritoneum for solute transfer but is associated with complications including protein loss, including transferrin (Tf) a key protein involved in iron transport. This study investigated Tf characteristics in ESKD patients compared to healthy individuals using lectin microarray, spectroscopic techniques and immunocytochemical analysis to assess Tf interaction with transferrin receptors (TfRs). ESKD patients exhibited altered Tf glycosylation patterns, evidenced by significant changes in lectin reactivity compared to healthy controls. However, structural analyses revealed no significant differences in the Tf secondary or tertiary structures between the two groups. A functional analysis demonstrated comparable Tf-TfR interaction in both PD and healthy samples. Despite significant alterations in Tf glycosylation, structural integrity and Tf-TfR interaction remained preserved in PD patients. These findings suggest that while glycosylation changes may influence iron metabolism, they do not impair Tf function. The study highlights the importance of a glucose-free dialysis solutions in managing anemia exacerbation in PD patients with poorly controlled anemia, potentially offering a targeted therapeutic approach to improve patient outcomes.
- Published
- 2024
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37. Investigation of the Potential of Selected Food-Derived Antioxidants to Bind and Stabilise the Bioactive Blue Protein C-Phycocyanin from Cyanobacteria Spirulina.
- Author
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Gligorijević N, Jovanović Z, Cvijetić I, Šunderić M, Veličković L, Katrlík J, Holazová A, Nikolić M, and Minić S
- Subjects
- Animals, Ubiquinone, Antioxidants pharmacology, Phycocyanin, Molecular Docking Simulation, Quercetin, Resveratrol pharmacology, Food Additives, Decapodiformes, Dietary Supplements, Protein C, Spirulina
- Abstract
Blue C-phycocyanin (C-PC), the major Spirulina protein with innumerable health-promoting benefits, is an attractive colourant and food supplement. A crucial obstacle to its more extensive use is its relatively low stability. This study aimed to screen various food-derived ligands for their ability to bind and stabilise C-PC, utilising spectroscopic techniques and molecular docking. Among twelve examined ligands, the protein fluorescence quenching revealed that only quercetin, coenzyme Q
10 and resveratrol had a moderate affinity to C-PC ( Ka of 2.2 to 3.7 × 105 M-1 ). Docking revealed these three ligands bind more strongly to the C-PC hexamer than the trimer, with the binding sites located at the interface of two (αβ)3 trimers. UV/VIS absorption spectroscopy demonstrated the changes in the C-PC absorption spectra in a complex with quercetin and resveratrol compared to the spectra of free protein and ligands. Selected ligands did not affect the secondary structure content, but they induced changes in the tertiary protein structure in the CD study. A fluorescence-based thermal stability assay demonstrated quercetin and coenzyme Q10 increased the C-PC melting point by nearly 5 °C. Our study identified food-derived ligands that interact with C-PC and improve its thermal stability, indicating their potential as stabilising agents for C-PC in the food industry.- Published
- 2023
- Full Text
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38. Correlation Theory of the Maxillary Central Incisor, Face and Dental Arch Shape in the Serbian Population.
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Kostić M, Đorđević NS, Gligorijević N, Jovanović M, Đerlek E, Todorović K, Jovanović G, Todić J, and Igić M
- Subjects
- Male, Humans, Female, Cross-Sectional Studies, Serbia, Odontometry, Maxilla, Incisor, Dental Arch
- Abstract
Background and Objectives : According to the modified Williams theory, the shape of the maxillary central incisor corresponds to the shape of the maxillary alveolar ridge (dental arch) and the shape of the face. Moreover, the standards of beauty suggest that the center of the face of an individual with a full set of teeth should match the center of the maxillary and mandibular dental arches. The purpose of this study is to conduct a comparative cross-sectional study on the matching of the shape of the face, maxillary central incisor and maxillary dental arch as well as the matching of the midfacial line and dental arches in subjects with complete dentition. Materials and Methods : The study included 90 subjects of both sexes. The matching of the shape of the face and midfacial line, i.e., dental arches and maxillary incisors, was determined by analysing photographs, whereas the shape of the dental arch was determined by analysing plaster models. Results : No significant gender-related differences were found either in the shape of the maxillary central incisor that matched the shape of the maxillary dental arch ( p = 0.349) or in the shape of the dental arch that matched the shape of the face ( p = 0.697). However, a significant difference was noted in the shape of the teeth that matched the shape of the face ( p = 0.043), which was more significantly impaired in men. In addition, the matching of the mid-face and the mid-dental arch was significantly greater in women ( p = 0.016). Conclusions : The modified Williams theory was confirmed in most subjects, thus it can be considered a relevant guideline when determining the shape of teeth after their loss. The highest percentage of matching in both sexes was with the shape of the face and dental arch. There was no positive correlation between the middle of the maxillary and mandibular dental arch in most cases.
- Published
- 2023
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39. Development and psychometric properties of the Serbian version of the Orofacial Esthetic Scale.
- Author
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Kostić M, Ignjatović A, Gligorijević N, Jovanović M, Đorđević NS, Đerlek A, and Igić M
- Subjects
- Humans, Serbia, Psychometrics methods, Reproducibility of Results, Surveys and Questionnaires, Esthetics, Dental, Language
- Abstract
Objective: The aim of the study was to develop the Serbian language version of the Orofacial Esthetic Scale questionnaire (OES SERB) and to evaluate its psychometric properties., Methods: The study included 226 subjects - 110 dental students and 116 patients (the validation sample). The students answered all the questions individually with the help of supervisors, whereas the prosthodontic patients were interviewed by the same trained dentist. The reliability and validity of the questionnaire were assessed., Results: Internal consistency of the OES-SERB was considered satisfactory (Cronbach's alpha 0.92, inter-item correlation coefficient ranged between 0.735 and 0.898). The construct validity of the OES was proved using exploratory factor analysis, which confirmed the one- dimensional model of the OES-SERB that assumed 66.549% of the variance. The Bartlett's test of sphericity was 1380.134 (df = 28, p < 0.001) and the Kaiser-Meyer-Olkin (KMO) test was 0.900. The total score was statistically significantly different between students and patients (p < 0.001), which confirmed the discriminant validity., Conclusion: The Serbian version of the OES, adapted to the cultural setting of the Republic of Serbia, has exhibited excellent psychometric properties and has been confirmed as a one-dimensional tool for self-assessment of the appearance of the orofacial region., Clinical Significance: The Serbian version of the OES has good psychometric properties and is a valuable instrument for self-assessment of the appearance of the orofacial region., (© 2023 Wiley Periodicals LLC.)
- Published
- 2023
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- View/download PDF
40. Exploring and strengthening the potential of R-phycocyanin from Nori flakes as a food colourant.
- Author
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Veličković L, Simović A, Gligorijević N, Thureau A, Obradović M, Vasović T, Sotiroudis G, Zoumpanioti M, Brûlet A, Ćirković Veličković T, Combet S, Nikolić M, and Minić S
- Subjects
- Phycocyanin chemistry, Antioxidants, Scattering, Small Angle, X-Ray Diffraction, Vegetables, Porphyra chemistry, Food Coloring Agents
- Abstract
This study aimed to purify, characterise and stabilise the natural food colourant, R-phycocyanin (R-PC), from the red algae Porphyra spp. (Nori). We purified R-PC from dried Nori flakes with a high purity ratio (A
618 /A280 ≥ 3.4) in native form (α-helix content 53%). SAXS measurements revealed that R-PC is trimeric ((αβ)3 ) in solution. The thermal denaturation of α-helix revealed one transition (Tm at 52 °C), while the pH stability study showed R-PC is stable in the pH range 4-8. The thermal treatment of R-PC at 60 °C has detrimental and irreversible effects on R-PC colour and antioxidant capacity (22 % of residual capacity). However, immobilisation of R-PC within calcium alginate beads completely preserves R-PC colour and mainly retains its antioxidant ability (78 % of residual capacity). Results give new insights into the stability of R-PC and preservation of its purple colour and bioactivity by encapsulation in calcium alginate beads., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)- Published
- 2023
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- View/download PDF
41. Ultrasensitive Quantification of Crustacean Tropomyosin by Immuno-PCR.
- Author
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Radomirović M, Gligorijević N, Stanić-Vučinić D, Rajković A, and Ćirković Veličković T
- Subjects
- Humans, Animals, Rabbits, Crustacea, Shellfish, Seafood analysis, Allergens, Tropomyosin genetics, Food Hypersensitivity diagnosis
- Abstract
Tropomyosin is the major and predominant allergen among shellfish. This study developed an ultrasensitive immuno-PCR method for the quantification of crustacean tropomyosin in foods. The method couples sandwich ELISA with the real-time PCR (rtPCR) amplification of marker DNAs. Monoclonal anti-TPM antibody was the capture antibody, polyclonal rabbit anti-shrimp tropomyosin antibody was the detection antibody, while natural shrimp tropomyosin served as the standard. A double-stranded amino-DNA was covalently conjugated to a secondary anti-rabbit antibody and subsequently amplified and quantified via rtPCR. The quantification sensitivity of immuno-PCR was 20-fold higher than analogous ELISA, with LOQ 19.8 pg/mL. The developed immuno-PCR method is highly specific for the detection of crustacean tropomyosin and is highly precise in a broad concentration range. Tropomyosin recovery in the spiked vegetable soup was 87.7-115.6%. Crustacean tropomyosin was also quantified in commercial food products. The reported immuno-PCR assay is the most sensitive method for the quantification of crustacean tropomyosin and is the first immuno-PCR-based assay for the quantification of food allergen and food protein in general. The described method could be easily adapted for the specific and ultrasensitive immuno-PCR-based detection of traces of any food allergen that is currently being quantified with ELISA, which is of critical importance for people with food allergies.
- Published
- 2023
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- View/download PDF
42. In vitro and in silico study of the biological activity of tetradentate Schiff base copper(II) complexes with ethylenediamine-bridge.
- Author
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Mijatović A, Gligorijević N, Ćoćić D, Spasić S, Lolić A, Aranđelović S, Nikolić M, and Baošić R
- Subjects
- Humans, Copper chemistry, Schiff Bases pharmacology, Schiff Bases chemistry, Antioxidants pharmacology, Molecular Docking Simulation, Cell Line, Tumor, Serum Albumin, Human chemistry, Ethylenediamines pharmacology, Ligands, Coordination Complexes pharmacology, Coordination Complexes chemistry, Adenocarcinoma, Colonic Neoplasms, Antineoplastic Agents pharmacology, Antineoplastic Agents chemistry
- Abstract
The biological activity of six structurally similar tetradentate Schiff base copper(II) complexes, namely [Cu(ethylenediamine-bis-acetylacetonate)] (CuAA) and five derivatives where two methyl groups are replaced by phenyl, (CuPP), CF3 (CuTT) or by mixed groups CH3/CF3 (CuAT), Ph/CF3 (CuPT), and Ph/CH3 (CuAP) has been investigated. The set of antioxidant assays was performed, and the results were expressed as IC
50 and EC50 values. The series of complexes showed interesting bioactivity and were investigated for the determination of antioxidant, antifungal, antimicrobial, and cytotoxic activity. A significant antioxidant behavior was exhibited by complex CuAA, greater than Trolox in the Oxygen Radical Absorbance Capacity (ORAC) assay. Antibacterial assay over Gram-positive and Gram-negative pathogenic bacterial strains and some fungal pathogens were studied. Antiproliferative activity of complexes in two human tumor cell lines, breast adenocarcinoma MCF-7, colon adenocarcinoma LS-174, and normal fibroblast cells-MRC-5, examined the effect on cell cycle progression. The significant cytotoxic potential, comparable to cisplatin cytotoxicity, was determined in human breast cancer cell line-MCF-7 with IC50 values being 17.53-31.40 μM and human colon cancer cell line-LS-174 with IC50 values being 15.22-23.92 μM. All tested compounds showed nearly twice more selectivity toward cancer cell lines than normal cells. The interactions of complexes with human serum albumin (HSA), the most prominent protein in plasma, were investigated using spectroscopic fluorescence techniques. The complexes bind to human serum albumin at multiple sites (n = 0.2-1.9), displaying a moderate binding constant Ka = 4.1-12.4 × 104 M-1 . The molecular docking experiment effectively showed complex binding to HSA and DNA molecular fragments., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests Aleksandar Mijatovic reports financial support was provided by University of Belgrade Faculty of Mining And Geology. Aleksandar Lolic reports financial support was provided by University of Belgrade Faculty of Chemistry., (Copyright © 2023 Elsevier Inc. All rights reserved.)- Published
- 2023
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43. Human Hemoglobin and Antipsychotics Clozapine, Ziprasidone and Sertindole: Friends or Foes?
- Author
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Platanić Arizanović L, Gligorijević N, Cvijetić I, Mijatović A, Ristivojević MK, Minić S, Kokić AN, Miljević Č, and Nikolić M
- Subjects
- Humans, Molecular Docking Simulation, Olanzapine, Benzodiazepines, Antipsychotic Agents pharmacology, Clozapine pharmacology
- Abstract
Packed with hemoglobin, an essential protein for oxygen transport, human erythrocytes are a suitable model system for testing the pleiotropic effects of lipophilic drugs. Our study investigated the interaction between antipsychotic drugs clozapine, ziprasidone, sertindole, and human hemoglobin under simulated physiological conditions. Analysis of protein fluorescence quenching at different temperatures and data obtained from the van't Hoff diagram and molecular docking indicate that the interactions are static and that the tetrameric human hemoglobin has one binding site for all drugs in the central cavity near αβ interfaces and is dominantly mediated through hydrophobic forces. The association constants were lower-moderate strength (~10
4 M-1 ), the highest observed for clozapine (2.2 × 104 M-1 at 25 °C). The clozapine binding showed "friendly" effects: increased α-helical content, a higher melting point, and protein protection from free radical-mediated oxidation. On the other hand, bound ziprasidone and sertindole had a slightly pro-oxidative effect, increasing ferrihemoglobin content, a possible "foe". Since the interaction of proteins with drugs plays a vital role in their pharmacokinetic and pharmacodynamic properties, the physiological significance of the obtained findings is briefly discussed.- Published
- 2023
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44. Significance of 1,25-Dihydroxyvitamin D 3 on Overall Mortality in Peritoneal Dialysis Patients with COVID-19.
- Author
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Baralić M, Robajac D, Penezić A, Brković V, Gligorijević N, Bontić A, Pavlović J, Nikolić J, Miljuš G, Dobrijević Z, Šunderić M, Pažitná L, Katrlík J, Nedić O, and Laušević M
- Subjects
- Humans, Calcitriol, Pandemics, SARS-CoV-2, Fibrinogen, COVID-19, Peritoneal Dialysis adverse effects, Hemostatics
- Abstract
In previous publications, we pointed out the importance of mannosylation of fibrinogen for the development of cardiovascular complications and fucosylation as a predictor of peritoneal membrane dysfunction in patients on peritoneal dialysis (PD). After a follow-up period of 30 months from the onset of the COVID-19 pandemic, we evaluated the significance of 1,25-dihydroxyvitamin D
3 (calcitriol) therapy, primary disease, biochemical and hematologic analyzes, and previously performed glycan analysis by lectin-based microarray as predictors of mortality in this patient group. After univariate Cox regression analysis, diabetes mellitus (DM) and calcitriol therapy were found to be potential predictors of mortality. Additional multivariate Cox regression analysis confirmed that only DM was a predictor of mortality. Nevertheless, the use of calcitriol in therapy significantly reduced mortality in this patient group, as shown by the Kaplan-Meier survival curve. The presence of DM as a concomitant disease proved to be a strong predictor of fatal outcome in PD patients infected with SARS-CoV-2. This is the first study to indicate the importance and beneficial effect of calcitriol therapy on survival in PD patients with COVID-19 infection. In addition, this study points to the possibility that adverse thrombogenic events observed in PD patients during the pandemic may be caused by aberrant fibrinogen glycosylation.- Published
- 2023
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45. Food Antioxidants and Their Interaction with Human Proteins.
- Author
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Nedić O, Penezić A, Minić S, Radomirović M, Nikolić M, Ćirković Veličković T, and Gligorijević N
- Abstract
Common to all biological systems and living organisms are molecular interactions, which may lead to specific physiological events. Most often, a cascade of events occurs, establishing an equilibrium between possibly competing and/or synergistic processes. Biochemical pathways that sustain life depend on multiple intrinsic and extrinsic factors contributing to aging and/or diseases. This article deals with food antioxidants and human proteins from the circulation, their interaction, their effect on the structure, properties, and function of antioxidant-bound proteins, and the possible impact of complex formation on antioxidants. An overview of studies examining interactions between individual antioxidant compounds and major blood proteins is presented with findings. Investigating antioxidant/protein interactions at the level of the human organism and determining antioxidant distribution between proteins and involvement in the particular physiological role is a very complex and challenging task. However, by knowing the role of a particular protein in certain pathology or aging, and the effect exerted by a particular antioxidant bound to it, it is possible to recommend specific food intake or resistance to it to improve the condition or slow down the process.
- Published
- 2023
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46. Exploring heterometallic bridged Pt(II)-Zn(II) complexes as potential antitumor agents.
- Author
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Soldatović TV, Šmit B, Mrkalić EM, Matić SL, Jelić RM, Serafinović MĆ, Gligorijević N, Čavić M, Aranđelović S, and Grgurić-Šipka S
- Subjects
- Humans, Molecular Docking Simulation, DNA chemistry, Pyrazines, Zinc, Antineoplastic Agents pharmacology, Antineoplastic Agents chemistry
- Abstract
The four novel complexes [{cis-PtCl(NH
3 )2 (μ-4,4'-bipyridyl)ZnCl(terpy)}](ClO4 )2 (C1), [{trans-PtCl(NH3 )2 (μ-4,4'-bipyridyl)ZnCl(terpy)}](ClO4 )2 (C2), [{cis-PtCl(NH3 )2 (μ-pyrazine)ZnCl(terpy)}](ClO4 )2 (C3) and [{trans-PtCl(NH3 )2 (μ-pyrazine)ZnCl(terpy)}](ClO4 )2 (C4) (where terpy = 2,2':6',2''-terpyridine) were synthesized and characterized. Acid-base titrations and concentration dependent kinetic measurements for the reactions with biologically relevant ligands such as guanosine-5'-monophosphate (5'-GMP), inosine-5'-monophosphate (5'-IMP) and glutathione (GSH), were studied at pH 7.4 and 37 °C. The binding of the heterometallic bridged cis- or trans-Pt(II)-Zn(II) complexes to calf thymus DNA (CT-DNA) was studied by UV absorption and fluorescence emission spectroscopy and molecular docking. The results indicated that the complexes bind strongly to DNA, through groove binding, hydrogen bonds, and hydrophobic or electrostatic interaction. The possible in vitro DNA protective effect of cis- and trans-Pt-L-Zn complexes has shown that C3 had significant dose-dependent DNA-protective effect and the same ability to inhibit peroxyl as well as hydroxyl radicals. Antiproliferative effect of the complexes, mRNA expression of apoptosis and repair-related genes after treatment in cancer cells indicated that newly synthesized C2 exhibited highly selective cytotoxicity toward colon carcinoma HCT116 cells. Only treatment with trans analog C2 induced effect similar to the typical DNA damaging agent such as cisplatin, characterized by p53 mediated cell response, cell cycle arrest and certain induction of apoptotic related genes. Both cis- and trans-isomers C1 and C2 showed potency to elicit expression of PARP1 mRNA and in vitro DNA binding., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)- Published
- 2023
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47. Cytotoxicity profiling of choline chloride-based natural deep eutectic solvents.
- Author
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Popović BM, Gligorijević N, Aranđelović S, Macedo AC, Jurić T, Uka D, Mocko-Blažek K, and Serra AT
- Abstract
This study aims to examine in detail for the first time the cytotoxic profile of twelve choline chloride-based deep eutectic solvents (NADES) against HT-29, Caco-2, MCF-7, and MRC-5 cell lines. All NADES systems were synthesized by microwave synthesis using choline chloride as a hydrogen bond acceptor (HBA) and selected sugars, alcohols, organic acids, and urea as hydrogen bond donors (HBD) with the addition of 20% water (w/w) to all systems. It was observed that the cytotoxic effect predominantly depended on the structure of HBD. Acidic systems, where HBDs were organic acids showed the highest cytotoxic effects in all investigated cell lines. The cytotoxicity depended mostly on the concentration of the NADES system in the cell medium as well as on the chemical constitution of the investigated systems. The highest cytotoxic effects showed acidic systems, especially to the HT-29 cell line. The EC
50 value for the citric acid-based system was 3.91 mg mL-1 for the HT-29 cell line which was the most vulnerable to acidic NADES systems., Competing Interests: The authors declare no competing interests., (This journal is © The Royal Society of Chemistry.)- Published
- 2023
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48. Prediction of Mortality in Patients on Peritoneal Dialysis Based on the Fibrinogen Mannosylation.
- Author
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Baralić M, Pažitná L, Brković V, Laušević M, Gligorijević N, Katrlík J, Nedić O, and Robajac D
- Subjects
- Humans, Fibrinogen, Mannose, Lectins, Polysaccharides chemistry, Peritoneal Dialysis, Kidney Failure, Chronic, Hemostatics
- Abstract
As we already reported, fibrinogen fucosylation emerged as a prognostic marker of peritoneal membrane function in end-stage renal disease (ESRD) patients on peritoneal dialysis. After a follow-up period of 18 months, we estimated the ability of employed lectins, as well as other biochemical parameters, to serve as mortality predictors in these patients. Following a univariate Cox regression analysis, ferritin, urea clearance, residual diuresis, hyperglycemia, and an increase in the signal intensity obtained with Galanthus nivalis lectin (GNL) emerged as potential mortality predictors, but additional multivariate Cox regression analysis pointed only to glucose concentration and GNL as mortality predictors. Higher signal intensity obtained with GNL in patients that died suggested the importance of paucimannosidic/highly mannosidic N-glycan structures on fibrinogen as factors that are related to unwanted cardiovascular events and all-cause mortality and can possibly be seen as a prediction tool. Altered glycan structures composed of mannose residues are expected to affect the reactivity of mannosylated glycoproteins with mannose-binding lectin and possibly the entire cascade of events linked to this lectin. Since patients with ESRD are prone to cardiovascular complications and the formation of atherosclerotic plaques, one can hypothesize that fibrinogen with increasingly exposed mannose residues may contribute to the unwanted events., Competing Interests: The authors declare no conflict of interest.
- Published
- 2023
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49. The association of human leucocyte antigen (HLA) alleles with COVID-19 severity: A systematic review and meta-analysis.
- Author
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Dobrijević Z, Gligorijević N, Šunderić M, Penezić A, Miljuš G, Tomić S, and Nedić O
- Subjects
- Humans, Alleles, HLA-DRB1 Chains genetics, Haplotypes, SARS-CoV-2 genetics, HLA-A Antigens genetics, HLA-B Antigens genetics, HLA-C Antigens genetics, COVID-19 diagnosis, COVID-19 genetics
- Abstract
Due to their pivotal role in orchestrating the immune response, HLA loci were recognized as candidates for genetic association studies related to the severity of COVID-19. Since the findings on the effects of HLA alleles on the outcome of SARS-CoV-2 infection remain inconclusive, we aimed to elucidate the potential involvement of genetic variability within HLA loci in the molecular genetics of COVID-19 by classifying the articles according to different disease severity/outcomes and by conducting a systematic review with meta-analysis. Potentially eligible studies were identified by searching PubMed, Scopus and Web of Science literature databases. A total of 28 studies with 13,073 participants were included in qualitative synthesis, while the results of 19 studies with 10,551 SARS-CoV-2-positive participants were pooled in the meta-analysis. According to the results of quantitative data synthesis, association with COVID-19 severity or with the lethal outcome was determined for the following alleles and allele families: HLA-A*01, HLA-A*03, HLA-A*11, HLA-A*23, HLA-A*31, HLA-A*68, HLA-A*68:02, HLA-B*07:02, HLA-B*14, HLA-B*15, HLA-B*40:02, HLA-B*51:01, HLA-B*53, HLA-B*54, HLA-B*54:01, HLA-C*04, HLA-C*04:01, HLA-C*06, HLA-C*07:02, HLA-DRB1*11, HLA-DRB1*15, HLA-DQB1*03 and HLA-DQB1*06 (assuming either allelic or dominant genetic model). We conclude that alleles of HLA-A, -B, -C, -DRB1 and -DQB1 loci may represent potential biomarkers of COVID-19 severity and/or mortality, which needs to be confirmed in a larger set of studies., (© 2022 John Wiley & Sons Ltd.)
- Published
- 2023
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50. Enriching Chemical Space of Bioactive Scaffolds by New Ring Systems: Benzazocines and Their Metal Complexes as Potential Anticancer Drugs.
- Author
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Kuznetcova I, Ostojić M, Gligorijević N, Aranđelović S, and Arion VB
- Subjects
- Humans, Copper pharmacology, Copper chemistry, Cisplatin pharmacology, Cell Line, Tumor, Glycogen Synthase Kinase 3 beta pharmacology, Cell Proliferation, Coordination Complexes pharmacology, Coordination Complexes chemistry, Antineoplastic Agents pharmacology, Antineoplastic Agents chemistry, Heterocyclic Compounds pharmacology, Colonic Neoplasms
- Abstract
The search for new scaffolds of medicinal significance combined with molecular shape enhances their innovative potential and continues to attract the attention of researchers. Herein, we report the synthesis, spectroscopic characterization (
1 H and13 C NMR, UV-vis, IR), ESI-mass spectrometry, and single-crystal X-ray diffraction analysis of a new ring system of medicinal significance, 5,6,7,9-tetrahydro-8 H -indolo[3,2- e ]benzazocin-8-one, and a series of derived potential ligands ( HL1 -HL5 ), as well as ruthenium(II), osmium(II), and copper(II) complexes ( 1a , 1b , and 2-5 ). The stability of compounds in 1% DMSO aqueous solutions has been confirmed by1 H NMR and UV-vis spectroscopy measurements. The antiproliferative activity of HL1 -HL5 and 1a , 1b , and 2-5 was evaluated by in vitro cytotoxicity tests against four cancer cell lines (LS-174, HCT116, MDA-MB-361, and A549) and one non-cancer cell line (MRC-5). The lead compounds HL5 and its copper(II) complex 5 were 15× and 17×, respectively, more cytotoxic than cisplatin against human colon cancer cell line HCT116. Annexin V-FITC apoptosis assay showed dominant apoptosis inducing potential of both compounds after prolonged treatment (48 h) in HCT116 cells. HL5 and 5 were found to induce a concentration- and time-dependent arrest of cell cycle in colon cancer cell lines. Antiproliferative activity of 5 in 3D multicellular tumor spheroid model of cancer cells (HCT116, LS-174) superior to that of cisplatin was found. Moreover, HL5 and 5 showed notable inhibition potency against glycogen synthase kinases (GSK-3α and GSK-3β), tyrosine-protein kinase (Src), lymphocyte-specific protein-tyrosine kinase (Lck), and cyclin-dependent kinases (Cdk2 and Cdk5) (IC50 = 1.4-6.1 μM), suggesting their multitargeted mode of action as potential anticancer drugs.- Published
- 2022
- Full Text
- View/download PDF
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