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Search Results: 1 - 10 of 465154 matches for " Sa?a Vukmirovi? "
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Anti-Oxidative Activity of An Aqueous Suspension of Commercial Preparation of The Mushroom Coprinus comatus
Mira Popovi?,Saa Vukmirovi,Neboj?a Stilinovi?,Ivan ?apo,Vida Jakovljevi?
Molecules , 2010, DOI: 10.3390/molecules15074564
Abstract: In this study the effects of an aqueous suspension of a commercial preparation of the mushroom Coprinus comatus on oxidative stress induced in rats by alloxane and carbon tetrachloride was examined. The effects were estimated from changes in the biochemical parameters (xanthine oxidase, glutathione peroxidase and catalase activity, reduced glutathione content, and extent of lipid peroxidation) of liver homogenate as well as histological changes in the liver of the rats treated with alloxane and carbon tetrachloride. Two screening doses of alloxane sufficient to induce diabetes in rats did not have any significant effect on the examined biochemical parameters of liver homogenate or on the cytoarchitectonics of liver cross-sections. Treatment with carbon tetrachloride resulted in a significant increase in the intensity of lipid peroxidation and peroxydasis activity, as well as with decrease in catalase activity. Certain changes in liver cross sections were detected, such is lymphocyte infiltration of dilated sinusoid capillaries. Administration of Coprinus comatus suspension thus showed antioxidative potential, evidenced by an increase of antioxidative status of liver homogenate and prevention of histological changes in liver cross sections.
The Protective Effects of Silymarin against Doxorubicin-Induced Cardiotoxicity and Hepatotoxicity in Rats
Aleksandar Ra?kovi?,Neboj?a Stilinovi?,Jovanka Kolarovi?,Velibor Vasovi?,Saa Vukmirovi,Momir Mikov
Molecules , 2011, DOI: 10.3390/molecules16108601
Abstract: Silymarin is a complex of five major compounds, and silibinin is the most biologically active component of the complex. The aim of this study was to investigate, evaluate and confirm the potential cardioprotective and hepatoprotective effects of administration of silymarin, rich in silibinin, at a dose of 60 mg/kg orally for a time-span of 12 days on doxorubicin induced toxicity in male Wistar rats. The in vivo model was used to explore whether silymarin could prevent damage of liver and heart tissue induced by doxorubicin administered every other day at dose of 1.66 mg/kg intraperitoneally for twelve days. In the study the change of body weight, ECG changes, biochemical parameters of oxidative stress, serum activity of alanine and aspartate transaminase, lactate dehydrogenase, creatine kinase and histological preparations of heart and liver samples of treated animals were examined. According to physiological, pharmacological, microscopic and biochemical results, we confirmed that at the examined dose, silymarin exhibits a protective influence on the heart and liver tissue against toxicity induced by doxorubicin.
Optimal Workflow Scheduling in Critical Infrastructure Systems with Neural Networks
S. Vukmirovi,A. Erdeljan,L. Imre,D. ?apko
Journal of applied research and technology , 2012,
Abstract: Critical infrastructure systems (CISs), such as power grids, transportation systems, communication networks and water systems are the backbone of a country’s national security and industrial prosperity. These CISs execute large numbers of workflows with very high resource requirements that can span through different systems and last for a long time. The proper functioning and synchronization of these workflows is essential since humanity’s well-being is connected to it. Because of this, the challenge of ensuring availability and reliability of these services in the face of a broad range of operating conditions is very complicated. This paper proposes an architecture which dynamically executes a scheduling algorithm using feedback about the current status of CIS nodes. Different artificial neural networks (ANNs) were created in order to solve the scheduling problem. Their performances were compared and as the main result of this paper, an optimal ANN architecture for workflow scheduling in CISs is proposed. A case study is shown for a meter data management system with measurements from a power distribution management system in Serbia. Performance tests show that significant improvement of the overall execution time can be achieved by ANNs.
Applying coefficients of preference in ranking (CPR)
Radoji?i? Zoran A.,Vukmirovi? Dragan V.,Vukovi? Nahod A.,Vojinovi? Milo?
Yugoslav Journal of Operations Research , 2003, DOI: 10.2298/yjor0302175r
Abstract: In marketing or medical research, especially in psychiatrics, it is very often necessary to define preference of examinees against defined object (persons, products, or phenomena). A question that is related to the object of preference is defined as like degree of like (positive preference) or as like degree of dislike (negative preference), where estimation is done as in scholar system (nominal or ordinal characteristics), with marks 1 through 5. Rank of objects achieved is very often expressed as average, which is not a good measure for realistic object ranking. In this paper, a coefficient of preference is presented as an effort to rank object more efficiently than average or other methods for ranking, especially in the meaning of preference. Preference is essential for humankind for decision making. One of the measures is Coefficients of Preference in Ranking (CPR) as shown. .
Bogdana Vuji?,Sr?an Vukmirovi,Goran Vuji?,Neboj?a M Jovi?i?
Thermal Science , 2010, DOI: tsci100507032v
Abstract: In the recent years, artificial neural networks (ANNs) have been used to predict the concentrations of various gaseous pollutants in ambient air, mainly to forecast mean daily particle concentrations. The data on traffic air pollution, irrespective of whether they are obtained by measuring or modelling, represent an important starting point for planning effective measures to improve air quality in urban areas. The aim of this study was to develop a mathematical model for predicting daily concentrations of air pollution caused by the traffic in urban areas. For the model development, experimental data have been collected for 10 months, covering all four seasons. The data about hourly concentration levels of suspended particles with aerodynamic diameter less than 10 μm (PM10) and meteorological data (temperature, air humidity, speed and direction of ind), measured at the measuring station in the town of Subotica from June 2008 to March 2009, served as the basis for developing an ANN-based model for forecasting mean daily concentrations of PM10. The quality of the ANN model was assessed on the basis of the statistical parameters, such as RMSE, MAE, MAPE, and r.
Hybrid artificial neural network system for short-term load forecasting
Ili? Slobodan A.,Vukmirovi? Sr?an M.,Erdeljan Aleksandar M.,Kuli? Filip J.
Thermal Science , 2012, DOI: 10.2298/tsci120130073i
Abstract: This paper presents a novel hybrid method for Short-Term Load Forecasting (STLF). The system comprises of two Artificial Neural Networks (ANN), assembled in a hierarchical order. The first ANN is a Multilayer Perceptron (MLP) which functions as integrated load predictor (ILP) for the forecasting day. The output of the ILP is then fed to another, more complex MLP, which acts as an hourly load predictor (HLP) for a forecasting day. By using a separate ANN that predicts the integral of the load (ILP), additional information is presented to the actual forecasting ANN (HLP), while keeping its input space relatively small. This property enables online training and adaptation, as new data become available, because of the short training time. Different sizes of training sets have been tested, and the optimum of 30 day sliding time-window has been determined. The system has been verified on recorded data from Serbian electrical utility company. The results demonstrate better efficiency of the proposed method in comparison to non-hybrid methods because it produces better forecasts and yields smaller mean average percentage error (MAPE).
Redesigning the network of pedestrian spaces in the function of reduction of CO2 emission. Case study: Pan evo and Vr ac
?uki? Aleksandra,Vukmirovi? Milena
Spatium , 2012, DOI: 10.2298/spat1227031d
Abstract: Research problem. The research problem is the increase of GHG and CO2 emissions in the transport sector, i.e. the intensification of urban transport activity in Serbia during the last 15 years. Focusing on redesigning of pedestrian networks as well as understanding the connections between urban design and pedestrian movement, the walkable environment could be achieved. In addition, as a direct result, a contribution would be made to a decrease of GHG and CO2 emission. Methodology. The following methods were used: analysis of the readability of open spaces, analysis of contents, rhythm and transparency on the ground floor of buildings and analysis of the intensity of use of open spaces using the Space Syntax method. Results. The results show a proportional relation between characteristics on ground floors of buildings and the intensity of pedestrian movement. Also, they enable the establishing of general recommendations for designing the immediate pedestrian environment and upgrading the quality of open public spaces. Conclusion. The improvement of the quality of pedestrian environment would have as its direct consequence greater use of open public spaces, and thus also increased intensity of pedestrian movement. In this manner, people would face a better quality and broader selection of contents and spaces.
Walking as a Climate Friendly Transportation Mode in Urban Environment Case Study: Belgrade
Aleksandra ?uki?,Milena Vukmirovi
International Journal for Traffic and Transport Engineering , 2011,
Abstract: A large percent of CO2 (carbon dioxide) emissions in Serbia originate from transport. In the last two decades, the number of private car users in Belgrade evidently increased compared to the number of users of environmentally friendly modes of transport. The purpose of this paper is to present an overview of approaches to the improvement of the physical aspect of the open public spaces, which aim to increase the number of users of climate friendly modes of transport, particularly walking. Research was done using three methods: observation of the intensity of pedestrian movement in relation to different periods during the day, direct surveys of citizens and the evaluation of immediate pedestrian surroundings. Three kinds of results were obtained: the trends and concentration of pedestrian movement along the main street lines; the attitude of citizens pertaining to reliable pedestrian movement and elements which contribute to their commitment to walking; and the rhythm of activity units, transparency, and variety of activities on the ground floor of buildings. The contribution of the study is in combining different research methods. The interpretation of the results forms the basis for directing future research and campaigns on topics of climate friendly modes of transport in urban areas.
Non-equilibrium Optical Conductivity in Materials with Localized Electronic States
Veljko Jankovi?,Nenad Vukmirovi
Physics , 2014, DOI: 10.1103/PhysRevB.90.224201
Abstract: A wide range of disordered materials contain electronic states that are spatially well localized. In this work, we investigated the electrical response of such systems in non-equilibrium conditions to external electromagnetic field. We obtained the expression for optical conductivity valid for any non-equilibrium state of electronic subsystem. In the case of incoherent non-equilibrium state, this expression contains only the positions of localized electronic states, Fermi's golden rule transition probabilities between the states and the populations of electronic states. The same form of expression is valid both in the case of weak electron-phonon interaction and weak electron-impurity interaction that act as perturbations of electronic Hamiltonian. The derivation was performed by expanding the general expression for AC conductivity in powers of small electron-phonon interaction or electron-impurity interaction parameter. Applications of the expression to two model systems, a simple one- dimensional Gaussian disorder model and the model of a realistic three-dimensional organic polymer material, were presented, as well.
Dynamics of exciton formation and relaxation in photoexcited semiconductors
Veljko Jankovi?,Nenad Vukmirovi
Physics , 2015,
Abstract: We investigate the dynamics of the exciton formation and relaxation on a picosecond time scale following a pulsed photoexcitation of a semiconductor. The study is conducted in the framework of the density matrix theory complemented with the dynamics controlled truncation scheme. We truncate the phonon branch of the resulting hierarchy of equations and propose the form of coupling among single-phonon-assisted and higher-order phonon-assisted density matrices so as to ensure the energy and particle-number conservation in a closed system. Time scales relevant for the exciton formation and relaxation processes are determined from numerical investigations performed on a one-dimensional model for the values of model parameters representative of a typical organic and inorganic semiconductor. The exciton dynamics is examined for different values of central frequency of the exciting field, temperature, and microscopic model parameters, such as the strengths of carrier-carrier and carrier-phonon couplings. We find that for typical organic semiconductor parameters, formation of bound excitons occurs on a several-hundred-femtosecond time scale, while their subsequent relaxation and equilibration takes at least several picoseconds. These time scales are consistent with recent experimental studies of the exciton formation and relaxation in conjugated polymer-based materials.
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