Antioxidative and Antiproliferative Activities of Different Horsetail (Equisetum arvense L.) Extracts

Dragana D. Četojević-Simin,Jasna M. C ˇ anadanovic´-Brunet,Gordana M. Bogdanovic,Sonja M. Djilas,Gordana S. C ´ etkovic,Vesna T. Tumbas,Bratislav T. Stojiljkovic 한국식품영양과학회 2010 Journal of medicinal food Vol.13 No.2

In this study we investigated antioxidative and antiproliferative activity of different horsetail (Equisetum arvense L.) extracts. The antioxidative activity was measured by the electron spin resonance (ESR) spectroscopy–spin trapping method. The influence of different horsetail extracts during lipid peroxidation of (1) sunflower oil induced by the lipophilic azo-initiator 4,4'-azobis(4-cyanovaleric acid) and (2) soybean phosphatidylcholine liposomes induced by the hydrophilic azo-initiator 2,2'-azobis(2-amidinopropane) dihydrochloride was studied. Antiproliferative activity was measured using the sulforhodamine B colorimetric assay on the human cancer cell lines HeLa, HT-29, and MCF7. The results of ESR analysis confirmed that the extracts investigated suppressed the formation of lipid peroxyl radicals in both systems investigated in a dose-dependent manner. The results indicate that n-butanol, methanol, ethyl acetate, and water extracts had significant peroxyl radical scavenging activity. Extracts inhibited cell growth that was dependent on cell line, type of extract, and extract concentration. Ethyl acetate extract exhibited the most prominent antiproliferative effect, without inducing any cell growth stimulation on human tumor cell lines. The results obtained suggest that the horsetail extracts could be used as an easily accessible source of natural antioxidants and as potential phytochemicals.

Changes in Antioxidant Enzyme Activity in Response to Salinity-induced Oxidative Stress during Early Growth of Sweet Basil

Dragana Z. Jakovljević,Marina D. Topuzović,Milan S. Stanković,Biljana M. Bojović 한국원예학회 2017 Horticulture, Environment, and Biotechnology Vol.58 No.3

Sweet basil is one of the most widely used commercially cultivated plants worldwide. Here, we investigatedthe early growth and antioxidant enzyme activity of salt-stressed sweet basil seedlings. We subjected in vitro-grownsweet basil (Ocimum basilicum L. var. minimum) to different levels of sodium chloride (0, 10, 20 and 30 mM) andcollected data per week during the first month of growth. The responses of antioxidant enzymes to salt stress werevariable. Superoxide dismutase (SOD) exhibited similar patterns of increasing and decreasing activity in both shootsand root. By contrast, pyrogallol peroxidase (PPOX) and guaiacol peroxidase (GPOX) activity increased during plantgrowth but varied among seedling parts. Catalase (CAT) was the most salinity-sensitive enzyme examined, with activitiesvarying depending on the plant part and stage of development. Our results also suggest that nutrient uptake is inhibitedin basil under salt stress and that antioxidative defence mechanisms are induced in salinity-stressed sweet basil duringearly development. The changes in nonspecific antioxidant biomarkers observed in this study could be highly valuablefor studying the mechanism underlying stress tolerance in O. basilicum L. var. minimum and could facilitate thedevelopment of tolerant basil cultivars.

Tensile and Corrosion Properties of Anodized Ultrafine‑Grained Ti–13Nb–13Zr Biomedical Alloy Obtained by High‑Pressure Torsion

Dragana Barjaktarević,Bojan Medjo,Primož Štefane,Nenad Gubeljak,Ivana Cvijović‑Alagić,Veljko Djokić,Marko Rakin 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.9

Severe plastic deformation (SPD) is a popular group of techniques applied to achieve the nanostructuring of the metallic biomaterials and improvement of their mechanical characteristics. One of the most commonly used SPD methods is the highpressure torsion (HPT) technique which enables the obtainment of the microstructure with small grains and high strength. In the present study, the influence of the plastic deformation and surface modification treatment on the tensile and corrosion properties of the Ti–13Nb–13Zr (wt%) alloy is investigated. In that purpose, the coarse-grained (CG) Ti–13Nb–13Zr (TNZ) alloy was subjected to the HPT processing by applying a pressure of 4.1 GPa with a rotational speed of 0.2 rpm and 5 revolutions at room temperature to obtain the ultrafine-grained (UFG) microstructure. The alloy microstructure before and after HPT processing was analysed using the scanning electron microscopy (SEM) and the X-ray diffraction (XRD). The homogeneity of the UFG TNZ alloy was determined by microhardness testing and microscopic observations. The nanotubular oxide layer on the surface of the TNZ alloy, both in CG and UFG condition, was formed by electrochemical anodization in 1 M H3PO4 + NaF electrolyte for 90 min. SEM analysis was used to characterise the morphology of the anodized surfaces, while energy dispersive spectroscopy was applied to determine the chemical composition of the nanostructured layers formed at the alloy surfaces. Mechanical properties of the TNZ alloy, before and after HPT processing and electrochemical anodization, were determined by tensile testing. After tensile testing, the fractographic analysis was conducted to identify the fracture mechanisms. The potentiodynamic polarization technique was used to determine the corrosion resistance of the alloy before and after plastic deformation and surface modification treatment. The obtained results showed that the alloy is reasonably homogeneous after the HPT processing. The XRD analyses reviled the presence of α′ and β phases in the CG TNZ alloy microstructure, while the additional ω phase was detected in the microstructure of the UFG TNZ alloy. The HPT obtained alloy exhibits higher hardness and improved tensile properties than the alloy in the as-received CG condition, while the electrochemical anodization leads to a decrease of its mechanical properties. Both CG and UFG alloys show excellent corrosion stability in Ringer’s solution. Moreover, electrochemical anodization leads to a decrease or an increase of the corrosion resistance of these materials, depending on the morphology of the formed nanotubular surface layers. The results indicate that the anodized CG TNZ alloy is characterized by a lower modulus of elasticity and better corrosion resistance properties than the anodized UFG TNZ alloy.

The solutions of some operator equations

Dragana S. Cvetkovic-Ilic 대한수학회 2008 대한수학회지 Vol.45 No.5

In this paper we consider the solvability and describe the set of the solutions of the operator equations AX + X*C = B and AXB + B*X*A*= C. This generalizes the results of D. S. Djordjevi´c [Explicit solution of the operator equation A*X+X*A=B, J. Comput. Appl. Math. 200 (2007), 701–704]. In this paper we consider the solvability and describe the set of the solutions of the operator equations AX + X*C = B and AXB + B*X*A*= C. This generalizes the results of D. S. Djordjevi´c [Explicit solution of the operator equation A*X+X*A=B, J. Comput. Appl. Math. 200 (2007), 701–704].

News Analysis of the Fukushima Accident: Lack of Information Disclosure, Radiation Fears and Accountability Issues

Lazic, Dragana World Association for Triple Helix and Future Stra 2013 Journal of Contemporary Eastern Asia Vol.12 No.2

Previous research assessed media reporting on nuclear accidents and risks, whilst studies about the Fukushima accident focused on the impact of the Internet on coverage of the incident. However, little research has addressed news framing or comparisons of the perceptions of journalists in relation to reporting nuclear accidents. The aim of this study is to apply framing analysis to news content in The New York Times, the Los Angeles Times, and USA Today about the Fukushima accident. It explores the question of how journalists view reporting on complex events. Content analysis of these three newspapers shows that conflict, responsibility, and economic consequences were the most frequently used frames. According to the journalists interviewed, the biggest problem was the inability to assess information due to contrary positions held by experts. It is argued that the Fukushima accident was framed as a conflict of experts and officials' opinions, utility and government officials' responsibility, and economic consequences for the United States. Adherence to professional norms of objectivity and impartiality was signified as the best approaches to risk reporting.

THE SOLUTIONS OF SOME OPERATOR EQUATIONS

Cvetkovic-Ilic, Dragana S. Korean Mathematical Society 2008 대한수학회지 Vol.45 No.5

In this paper we consider the solvability and describe the set of the solutions of the operator equations $AX+X^{*}C=B$ and $AXB+B^{*}X^{*}A^{*}=C$. This generalizes the results of D. S. Djordjevic [Explicit solution of the operator equation $A^{*}X+X^{*}$A=B, J. Comput. Appl. Math. 200(2007), 701-704].

Challenges of Public Administration Reform in Serbia: Between Requirements and Reality

Miloš Đinđić,Dragana Bajić 한국외국어대학교(글로벌캠퍼스) 러시아연구소 2018 REGION Vol.7 No.2

Informal systemic practices in Serbia embedded in the political and administrative milieu impair public administration reform efforts. Formal rules produce no real incentives for achieving effective reform outcomes and suppressing these informalities. External conditionality provides incentives as it puts pressure on institutional actors to pursue reforms, promising the often vague but important prospect of European Union membership. Although effective in initiating change in formal procedures, external incentives still fall short of deconstructing informal practices that circumvent written norms and standards, despite pressures and conditionality. In this paper, the authors argue that parallelism between formal rules that exist on paper, and reality, which is resistant to these same rules, results in a “reform faking” syndrome characterized by the acceptance of formal standards that the system finds difficult to absorb, despite internal and external demands to apply them. The paper goes on to argue that the embedded practice of fabricating reforms carries long-term consequences for system stability and the rule of law.

Statistical causality and extremal measures

Ljiljana Petrovic,Dragana Valjarevic 대한수학회 2018 대한수학회보 Vol.55 No.2

In this paper we consider the concept of statistical causality in continuous time between flows of information, represented by filtrations. Then we relate the given concept of causality to the equivalent change of measure that plays an important role in mathematical finance. We give necessary and sufficient conditions, in terms of statistical causali\-ty, for extremality of measure in the set of martingale measures. Also, we have considered the extremality of measure which involves the stopping time and the stopped processes, and obtained similar results. Finally, we show that the concept of unique equivalent martingale measure is strongly connected to the given concept of causality and apply this result to the continuous market model.

Genetic Diversity of Orobanche cumana Populations in Serbia

Ž,arko Ivanović,Dragana Marisavljević,Radovan Marinković,Petar Mitrović,Jovana Blagojević,Ivan Nikolić,Danijela Pavlović 한국식물병리학회 2021 Plant Pathology Journal Vol.37 No.6

In this study, we report genetic characterization of Oro- banche cumana, the causal agent of sunflower wilting in Serbia. The genetic diversity of this parasitic plant in Serbia was not studied before. Random amplified polymorphic DNA (RAPD) markers and partial rbcL gene sequences analysis were used to characterize the O. cumana populations at the molecular level. While phylogenetic analyses of RAPD-PCR amplicons were performed using unweighted pair-group Method analy- ses, rbcL gene sequences were analyzed using neigbor joining method and minimum spanning tree. Molecular analyses of RAPD-PCR analysis revealed high genetic diversity of O. cumana populations which indicated high adaptive potential of this parasitic weed in Serbia. Further analyses of rbcL gene using minimum span- ning tree revealed clear differences among diverse sections of Orobanche genus. Although this molecular marker lacked the resolution to display intrapopulation diversity it could be a useful tool for understanding the evolution of this parasitic plant. Our results suggested that O. cumana has great genetic potential which can lead to differentiation of more virulent races which is important for determining crop breeding strategies for their control.

STATISTICAL CAUSALITY AND EXTREMAL MEASURES

Petrovic, Ljiljana,Valjarevic, Dragana Korean Mathematical Society 2018 대한수학회보 Vol.55 No.2

In this paper we consider the concept of statistical causality in continuous time between flows of information, represented by filtrations. Then we relate the given concept of causality to the equivalent change of measure that plays an important role in mathematical finance. We give necessary and sufficient conditions, in terms of statistical causality, for extremality of measure in the set of martingale measures. Also, we have considered the extremality of measure which involves the stopping time and the stopped processes, and obtained similar results. Finally, we show that the concept of unique equivalent martingale measure is strongly connected to the given concept of causality and apply this result to the continuous market model.