Assessment of the quality of newly-formed bone for implant insertion after augmentation of the maxillary sinus floor

Background: Presence of the maxillary sinus and low bone density in this area often could create a problem for prosthetic rehabilitation with dental implants. Sinus floor augmentation technique can successfully increase dimensions of the posterior maxilla for implant placement. Objective: To assess quality of newly formed bone for implant insertion after augmentation of the floor of the maxillary sinus using Digora for Windows computer programme. Materials and Methods: 30 patients with indications for sinus lift procedure were involved in this clinical study. Bone density was analyzed by Digora for Windows computer programme. Results: 16 patients completed this clinical study with preoperative and postoperative orthopantomographs. Conclusion: Cases with sufficient density and bone volume in the posterior maxilla require sinus lift technique with adequate bone graft for implant insertion. This is confirmed by pre- and post-operative analysis of radiographic images in Digora for Windows programme

Geopolitical positioning of the Russian federation after the intervention in Syria

Историја 20. века обележена је са два велика, светска рата, као и са великим бројем мањих, регионалних сукоба, који су били део борбе за глобалну превласт и доминацију у погледу друштвених релација, организације друштва, тржишта, политичког и социјалног усмерења мањих народа и држава. Такође, током добро познатог Хладног рата „мали“ народи су по неписаном правилу били принуђени да се опредељују за приклањање једном од два супротстављена блока. Окончањем Хладног рата и сломом совјетског модела доминације погрешно се претпостављало у другом, победичком блоку, да је победа коначна те да је дошло време апсолутне превласти интереса и мишљења преостале глобалне суперсиле, Сједињених Америчких Држава (САД). Ипак, време апсолутне доминације трајаће, историјски посматрано, јако кратко, тек нешто више од 20 година, када се поново полако почиње успостављати одређена равнотежа глобалне моћи јачањем пре свих Кине, Европске Уније, Индије, као и Руске Федерације, формално-правне наследнице СССР-а па и делимично совјетског модела друштвеног и политичког уређења. Временски период своје апсолутне доминације САД су искористиле за глобално приближавање границама интересног утицаја како Кине, тако и Руске Федерације, задирући у територије вишегодишњег глобалног позиционирања наведених држава, као глобалних и регионалних сила. Јачање политичких па и војних притисака на пробуђену Русију у другој декади 21. века доводи до повећања субјективног осећаја сопствене угрожености, која ипак није била толико изражена у војном колико у економском погледу, будући да су активности западних сила тежишно биле усмерене ка ограничавању руског снабдевања Европе природним гасом. Узимајући у обзир значај и удео енергетике у укупном привредном билансу Руске Федеције, војна интервенција ове државе у Сирији била је од виталног значаја за њен даљи економски развој. Руска Федерација је овим искораком, још једном, од окончања Хладног рата успела да заустави експанзионистичку политичку и војна настојања Вашингтона, пре свега за успоставом доминације и изласком на интересне па чак и на државне границе Руске Федерације.The history of the 20th century is marked by two great, world wars, as well as a large number of smaller, regional conflicts, which were part of the struggle for global supremacy and domination in terms of social relations, organization of society, markets, political and social orientation of smaller nations and country. Also, during the well-known Cold War, „small“ nations were, by an unwritten rule, forced to opt for one of the two opposing blocs. With the end of the Cold War and the collapse of the Soviet model of domination, it was wrongly assumed in the second, victorious bloc, that victory was final and that the time had come for the absolute dominance of interests and opinions of the remaining global superpower, the United States (USA). However, the time of absolute domination will last, historically speaking, very short, just over 20 years, when a certain balance of global power is slowly being re-established by strengthening China, the European Union, India, as well as the Russian Federation, the formal legal successor of the USSR, and even a partially Soviet model of social and political organization. The United States used the time period of its absolute domination to globally approach the borders of interesting influence of both China and the Russian Federation, encroaching on the territories of many years of global positioning of these countries, as global and regional powers. The intensification of political and even military pressures on awakened Russia in the second decade of the 21st century leads to an increase in the subjective feeling of self-threat, which was not so much expressed in military as in economic terms, since the activities of Western powers were focused on limiting Russia's supply to Europe. natural gas. Taking into account the importance and share of energy in the overall economic balance of the Russian Federation, the military intervention of this country in Syria was of vital importance for its further economic development. With this step forward, once again since the end of the Cold War, the Russian Federation has managed to stop the expansionist political and military efforts of Washington, above all, to establish dominance and reach the interesting and even state borders of the Russian Federation

On the brachistochrone of a variable mass particle in general force fields

The problem of the brachistochronic motion of a variable mass particle is considered. The particle moves through a resistant medium in the field of arbitrary active forces. Beginning from these general assumptions, and applying Pontryagin's minimum principle along with singular optimal control theory, a corresponding two-point boundary value problem is obtained and solved. The solution proposed involves an appropriate numerical procedure based upon the shooting method. In this numerical procedure, the evaluation of ranges for unknown values of costate variables is avoided by the choice of a corresponding Cartesian coordinate of the particle as an independent variable. A numerical example assuming the resistance force proportional to the square of the particle speed is presented. A review of existing results for related problems is provided, and it can be shown that these problems may be regarded as special cases of the brachistochrone problem formulated and solved in this paper under very general assumptions by means of optimal control theory

The brachistochronic motion of a wheeled vehicle

The paper considers the brachistochronic motion of a wheeled vehicle on a horizontal plane surface. The objective is to transfer the vehicle from the specified initial position with given initial kinetic energy to the specified terminal position in minimum time with conserved total mechanical energy of the vehicle. The problem is solved by applying Pontryagin's maximum principle and singular optimal control theory. The projection of the reaction force of the horizontal plane applied on the front vehicle wheels onto the axis of the front vehicle axle is taken for a control variable. The cases of unbounded and bounded value of this projection are considered. The shooting method is used to solve the two-point boundary value problem arising from Pontryagin's maximum principle and singular optimal control theory.This is the peer reviewed version of the article:Radulović, R.; Obradović, A.; Šalinić, S.; Mitrović, Z. The Brachistochronic Motion of a Wheeled Vehicle. Nonlinear Dynamics 2017, 87 (1), 191–205. [https://doi.org/10.1007/s11071-016-3035-3

A quality of life assessment and the correlation between generic and disease-specific questionnaires scores in outpatients with chronic liver disease-pilot study

Introduction. Chronic liver diseases (CLD) are an important cause of morbidity and mortality in general population. The aim of this study was to analyze potential differences between patients with CLD and healthy control group, and to estimate the severity of CLD by using simple questionnaires: general health questionnaire (GHQ-12) and chronic liver disease questionnaire (CLDQ). Methods. A cross-sectional pilot study was performed in Zemun Clinical Hospital during years 2014 and 2015. Sixty participants were divided into 4 groups (15 per group): chronic alcoholic hepatitis, other chronic hepatitis, liver cirrhosis, and healthy control group. Entire study population chose one of four offered answers of structured questionnaires GHQ-12 and CLDQ, based on which mean model of end-stage liver disease (MELD) and Child-Turcotte-Pugh (CTP) scores were calculated. Results. Mean GHQ12 and CLDQ scores were 10.5 and 5.21 +/- 1.11 respectively. Regarding certain CLDQ domain scores, a significant difference between alcoholic and non-alcoholic hepatitis groups in the worry domain was observed. Mean MELD score was 7.42 +/- 2.89 and did not differ between chronic hepatitis groups, while mean CTP score was 5.73 +/- 0.88. A statistically significant correlation was observed between GHQ12 and CLDQ scores (rho = -0.404, p LT 0.01), but not between subjective and objective scores. Conclusions. Mean GHQ12 and CLDQ scores pointed out to general psychological no-distress condition of the studied participants, as well as scarcely expressed CLD-specific complaints. Mean MELD and CTP scores indicated stable chronic liver diseases, with low three-month mortality rates in the cases of chronic hepatitis, as well as determination to Child A group in the case of liver cirrhosis

Free vibration of structures composed of rigid bodies and elastic beam segments

Free vibration of structures composed of rigid bodies and elastic beam segments is considered, assuming that the mass centers of rigid bodies are not located on the neutral axes of undeformed elastic beam segments. It is assumed that the rigid bodies of the system perform planar motion in the same plane and that their mass centers are located in that plane. The elastic beam segments are treated as the Euler-Bernoulli beams. In order to determine natural frequencies of the system, modification of the conventional continuous-mass transfer matrix method has been clone. The order of the overall transfer matrix has been reduced by this modification. Theoretical considerations are accompanied by two numerical examples.This is the peer reviewed version of the article: Obradović, A.; Šalinić, S.; Trifković, D.; Zorić, N.; Stokić, Z. Free Vibration of Structures Composed of Rigid Bodies and Elastic Beam Segments. Journal of Sound and Vibration 2015, 347, 126–138. [https://doi.org/10.1016/j.jsv.2015.03.001

Fuzzy model for braking force maximization

This paper shows the process of braking force realization by air brakes with brake shoes accompanied by a suitable mechanical model. The complexity of adhesion nature as a physical phenomenon as well as the limited factors on which the braking force value depends are pointed out. According to this, the model of braking force realization based on the fuzzy set theory is explained. The procedure of fuzzy controller projecting with a task to regulate the value of kidding and by that the value of braking torque through the air pressure in the braking cylinder by maximizing the braking force that can be realized according to adhesion conditions is described. The testing of the optimization model under concrete adhesion conditions of the wheels on the rails is done at the end of the paper