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Periodontal disease is a chronic infection of periodontal tissue characterized by extracellular matrix (ECM) degradation due to increased expression of plasminogen activators and matrix metalloproteinases (MMPs) and various proinflammatory cytokines, including interleukin (IL)-17. Successful regeneration of damaged periodontal tissues depends on the proper functionality of periodontal ligament mesenchymal stem cells (PDLMSCs), especially the production of extracellular matrix proteases. We investigated the influence of IL-17 on ECM remodeling through modulation of urokinasetype plasminogen activator (uPA) and MMP2/MMP9 expression in human PDLMSCs at mRNA, protein and activity levels using by RT-PCR, Western blotting and zymography, respectively. Investigation of the involvement of MAPKs in these processes in PDLMSCs was determined by Western blotting, as well as by utilizing specific p38 and MEK1/2 inhibitors. Our results show that IL-17 activates MAPK signaling in PDLMSCs. Moreover, IL-17 had no effect on MMP9 expression, but it stimulated uPA and MMP2 gene and protein expression in PDLMSCs through the activation of the ERK1/2 MAPK signaling pathway. The obtained data suggest that IL-17 contributes to ECM degradation in the periodontal ligament by stimulating uPA and MMP2 expression and activity in PDLMSCs. This information is important for understanding periodontal disease development and defining future directions of its treatment.

Educational tourism is a selective form of thematic tourism and implies a trend of acquiring new knowledge, transferring knowledge to others, as well as improving skills outside the classroom. It implies a tourist activity in which education is the primary or secondary motive for staying at the destination. The main goal of the travel is focused on activities that include visits to other countries to learn about different cultures. These include student exchange programs and study trips, work, and skills development in different and new environments, such as numerous international internships. There is a difference between travels where education is not the main motive; however, during the holiday guests are educated about certain aspects of the tourist offer (e.g. cultural attractions) and travels where education is the main motive for travel and stay at the destination.

It is a well-known fact that practice in clinical, mental health, or forensic psychology, as well as in other applied psychological disciplines, is always a few steps ahead of the theoretical framework. It is the practical work, experience, and research that lead to acquiring new knowledge and contribute to the theoretical base. The modern world has been flooded by a wave of aggression and destruction in the recent decades, most prominently by younger population. Having this in mind, we have focused not only on studying a sample of children and adolescents who exhibit delinquent and asocial behaviour-who may or may not be characterized as delinquents and criminal offenders-but also on the underlying causes of such behaviour. Due to the volume restrictions, this paper will hone in on the correlation of family relationships, character traits, and tendency towards aggressive behaviour in adolescents with a view of generating guidelines for the practical work in clinical psychology, where special emphasis is placed on the correlation-as well as the predictive potential-of the family relationships to the models of aggressive hostility. The study aims at determining whether family relationships are statistical predictors of the degree of manifestation of aggression and hostility. The results indicate that the dimensions of family relationships present good predictors of different categories of aggressive and hostile behaviour in adolescents. The research sample consists of 212 high school students in the Kosovska Mitrovica school district. The main research instruments are: FACES IV, Big-Five inventory (BFI), and BDHI scale. In conclusion, the practical and theoretical contribution of this study, as a part of the ongoing series, is summarized as follows: 1) the study expands on the range of the instruments used in psychodiagnostics of children and adolescents owing to the methodological principles of the clinical approach such as group framework, openness of the batteries of psychodiagnostic tests, multidimensionality, favouring the wide-range techniques, and explorativity; 2) in terms of forensic psychology-which is linked to clinical psychology as an applied discipline, especially with psychodiagnostic and specifically with psychodiagnostic of children and adolescents-the research results indicate a more successful evaluation of the most probable truth for an individual in the given circumstances by introducing new psychodiagnostic instruments in the legal process; 3) the study highlighted several predictors of family relationship dimensions and the manifestation of aggressive and hostile behaviour in adolescents, which promotes preventive measures in ensuring and nourishing mental health of children and adolescents and their families in a wider social community; and 4) hopefully, the study contributed to the overall evaluation and prediction of the behavioural patterns of children and adolescents and the correlation of their family relationships and the tendency towards aggression.

The molecular mechanism by which electron transfer (ET) is coupled to proton pumping in cytochrome oxidase is one of the main unsolved problems in biochemistry. Particularly, the nature and position of the proton-loading site is under dispute. The CuB complex has three ligated histidines, whereas only His290 and His291 are ionizable sites with the same pKa values in aqueous solution, but apparently quite different ones within the enzyme. Earlier, a model of proton pumping with the central role of His290 was proposed. Recent calculations indicate that the His291 ligand of the CuB center might play the role of the pumping element, since its protonation state depends on the oxidation state of the binuclear complex (BNC). The present electrostatic study was applied to assess the role of the protein environment on the acidity of the two histidines. Their pKa values and effects of different energy terms were evaluated to discover the nature of their diverse behavior in the enzyme. Here, a new set of pKa values for the non-standard model compounds within the BNC was applied. The enhanced results are compared with results of previous studies in the light of the plausible proton pumping mechanism. The obtained microscopic and apparent pKa values in the oxidized state of BNC are virtually the same, indicating that deprotonated form of His291 accounts for the large pKa increase of His290, since then both titratable sites on then CuB center cannot simultaneously be in the charged state. The present results support the underlined His291 pumping model.

Interpreting the extensive and varied bibliography of Jovan Cvijić, largely in foreign languages, which apart from the text includes geographic and ethnographic map of the Balkan Peninsula, atlases, notes and drawings, it is concluded that his scientific work was versatile and complex. Cvijić's perception of space, the use of didactic principles, methods and forms of work can be categorized as actual and modern even in the present time. He was the first among the Balkan geographers who simultaneously interpreted natural, historical, sociological, ethnographic and ethno-psychological phenomena and processes. Cvijić pointed to the relationship between the geographic environment and human communities, civilizations and historical events, constantly examining their mutual conditionality. Numerous research trips in almost all regions of the Balkan Peninsula led to his interest in the culture and customs of the people. He noted that in the Balkans, there are different people by origin, religion and mentality. The result of the field research is certainly one of Cvijić's most important work - 'Anthropogeographical problems of the Balkan Peninsula'. His scientific approach has given an outstanding contribution to methodological development of geography.

In order to meet the needs of modern society, schools should be continually reviewed its role. In contemporary the methodological concepts, interdisciplinary teaching is seen as a necessity in order to increase the quality of teaching and teaching an improved outcome. Analysis Curriculum geography of 5th to 8th graders and items that are correlated with it indicates that there are a number of lessons that provide quality basis for the realization of interdisciplinary teaching and learning. The aim is to determine the program content items geography in primary school that are suitable for an interdisciplinary approach to teaching. Test results indicate the great potential of interdisciplinary connections between teaching content of geography and other subjects in primary school. The paper contained proposals that could contribute to the improvement of the interdisciplinary approach. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 176008]

The interdisciplinary teaching-scientific disciplines and all participants in the educational process, the school becomes an environment in which, in addition to teaching and learning, fosters the harmonious development of personality of students with various aspects. Geography and ethnology ratio is determined by their position in the system of scientific disciplines and tasks that have in education. From ethnology as a science is the selection of content, according to educational and functional tasks of teaching geography in specific socio-historical context. In geography textbooks represented ethnological themes through the study of the origin, beliefs and customs of a nation or community. As such, characteristics of the different analyzed ethnology people, by studying the relations between them, and thus enrich the geography textbooks. Ethnological facilities are very suitable for the teaching process because they enable wide application forms and methods, as well as a wide selection of new information and communication educational technologies. The aim of this paper is based on defining similarities and differences between geography and ethnology, as well as related and in many ways related to science and unbreakable. The aim of the paper points to the scale of the ethnological contents in geography textbooks for Secondary school. The results show that in terms of geography and ethnology, there are some similarities, but also differences when it comes to the interpretation of certain phenomena, processes and principles. Based on the results, proposals are defined which are contributing to a more efficient study of ethnological content with the aim of more obvious, more permanent and more practical adoption of students' knowledge.

Cobalt(III) complexes derived from thio- and selenosemicarbazone ligands have been studied to elucidate the nature and consequences of S to Se substitution on their possible biological activity. Solid state structures of cobalt(III) complexes with bis-tridentate coordinated 2-quinolinecarboxaldehyde thio- and selenosemicarbazone were determined by single crystal X-ray diffraction analysis. The complexes were also characterized by spectroscopic methods and cyclic voltammetry. Electronic properties of the complexes were studied using DFT and TD–DFT methods. Finally, evident in vitro antioxidant activity of the complexes was demonstrated. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 172035 and Grant no. 172055]

Municipality of Negotin is an area of rural character, one of the most agrarian in Serbia. Rural development, as one of the areas of regional policy is a key instrument for the restructuring of the agricultural sector, has a task to focus and strategic use of the potential of attractive tourist village. At the time of increasing urbanization and globalization, specific indigenous settlements accurately reflect the spirit and tradition of ancient times are gaining a certain cultural, economic, and tourist importance. Municipality of Negotin has good conditions for the development of rural tourism thanks to its geographical position, varied landscape (vari­ous forms of recreation), gastronomy, folklore, rich cultural heritage. Rural tourism should contribute to the preservation of the rural environment and cultural heritage, but also economically motivate the local population to remain in the countryside. This form of tourism could contribute significantly to the protection of nature, but also to provide resources for the survival and development of the village.

An approach to model the trans-influence using partial atomic charges derived from the molecular electrostatic potential by means of the restrained electrostatic potential (RESP) fitting method is exemplified on a series of halogenido-ammine octahedral chromium(III) complexes. RESP charges incorporated in our vibrationally optimized consistent force field account for second-order phenomena, improve the modeling and assignment of skeletal vibrations, and reproduce the trends in frequency shifts along the (F, Cl, Br, I) series. In addition, a supplementary statistical analysis is given for Cr-halogen bonds in crystal structures from CSD. [Projekat Ministarstva nauke Republike Srbije, br. 172035]

Mesenchymal stem cells (MSCs) were isolated from human periodontal ligament (hPDL-MSCs) and characterized by their morphology, clonogenic efficiency, proliferation and differentiation capabilities. hPDL-MSCs, derived from normal impacted third molars, possessed all of the properties of MSC, including clonogenic ability, high proliferation rate and multi-lineage (osteogenic, chondrogenic, adipogenic, myogenic) differentiation potential. Moreover, hPDL-MSCs expressed a typical MSC epitope profile, being positive for mesenchymal cell markers (CD44H, CD90, CD105, CD73, CD29, Stro-1, fibronectin, vimentin, α-SMA), and negative for hematopoietic stem cell markers (CD34, CD11b, CD45, Glycophorin-CD235a). Additionally, hPDL-MSCs, as primitive and highly multipotent cells, showed high expression of embryonic markers (Nanog, Sox2, SSEA4). The data obtained provided yet further proof that cells with mesenchymal properties can be obtained from periodontal ligament tissue. Although these cells should be further investigated to determine their clinical significance, hPDL-MSCs are believed to provide a renewable and promising cell source for new therapeutic strategies in the treatment of periodontal defects. [Projekat Ministarstva nauke Republike Srbije, br. 175062 i br. III 41011]

Introduction. Mesenchymal stem cells (MSCs) are a promising tool for regenerative medicine, but due to the heterogeneity of their populations, different sources and isolation techniques, the characteristics defining MSCs are inconsistent. Objective. The aim of this study was to compare the characteristics of MSCs derived from two different human tissues: peripheral blood (PB-MSCs) and umbilical cord Wharton’s Jelly (UC-MSCs). Methods. The PB-MSC and UC-MSC were isolated by adherence to plastic after gradient-density separation or an explant culture method, respectively, and compared regarding their morphology, clonogenic efficiency, proliferating rates, immunophenotype and differentiation potential. Results. MSCs derived from both sources exhibit similar morphology, proliferation capacity and multilineage (osteogenic, chondrogenic, adipogenic and myogenic) differentiation potential. Differences were observed in the clonogenic capacity and the immunophenotype, since UC-MSCs showed higher CFU-F (colony-forming units-fibroblastic) cloning efficiency, as well as higher embryonic markers (Nanog, Sox2, SSEA4) expression. When additional surface antigens were analyzed by flow cytometry (CD44, CD90, CD105, CD33, CD34, CD45, CD11b, CD235a) or immunofluorescent labeling (vimentin, STRO-1 and α-smooth muscle actin), most appeared to have similar epitope profiles irrespective of MSC source. Conclusion. The results obtained demonstrated that both MSCs represent good alternative sources of adult MSCs that could be used in cell therapy applications. [Projekat Ministarstva nauke Republike Srbije, br. 175062]

Non-equilibrium plasmas have been used as one of the principal technologies for development of microelectronics and they are the basis for the development of new generations of nano-electronics devices required for 65 and 40 nm technologies. Microdischarges recently have become more common in everyday life. Technology of plasma etching has enabled us to develop such discharges and the field of microdischarges has grown into the most interesting field of the physics of collisional non-equilibrium plasmas. Recently, an effort to fabricate microplasma sources that can be integrated with other MEMS devices to form larger Microsystems has been made. Plasma-based microsystems can find application in bio-microelectro- mechanical system (bio-MEMS) sterilization, small-scale materials processing and microchemical analysis systems. However, integrability requires not only a size reduction, but also an understanding of the physics governing the new small-scale discharges. In this paper, we have performed modeling of a breakdown voltage by using Particle-in-Cell/Monte Carlo collision (PIC/MCC) code taking into account the secondary electron emission due to a high field.

Background/Aim. Thoracic drainage is a surgical procedure for introducing a drain into the pleural space to drain its contents. Using this method, the pleura is discharged and set to the physiological state which enables the reexpansion of the lungs. The aim of the study was to prove that the use of modern principles and protocols of thoracic drainage significantly reduces the occurrence of failures and complications, rendering the treatment more efficient. Methods. The study included 967 patients treated by thoracic drainage within the period from January 1, 1989 to June 1, 2000. The studied patients were divided into 2 groups: group A of 463 patients treated in the period from January 1, 1989 to December 31, 1994 in whom 386 pleural drainage (83.36%) were performed, and group B of 602 patients treated form January 1, 1995 to June 1, 2000 in whom 581 pleural drainage (96.51%) were performed. The patients of the group A were drained using the classical standards of thoracic drainage by the general surgeons. The patients of the group B, however, were drained using the modern standards of thoracic drainage by the thoracic surgeons, and the general surgeons trained for this kind of the surgery. Results. The study showed that better results were achieved in the treatment of the patients from the group B. The total incidence of the failures and complications of thoracic drainage decreased from 36.52% (group A) to 12.73% (group B). The mean length of hospitalization of the patients without complications in the group A was 19.5 days versus 10 days in the group B. The mean length of the treatment of the patients with failures and complications of the drainage in the group A was 33.5 days versus 17.5 days in the group B. Conclusion. The shorter length of hospitalization and the lower morbidity of the studied patients were considered to be the result of the correct treatment using modern principles of thoracic drainage, a suitable surgical technique, and a careful follow-up of the patients.