65 results on '"Stevanović, Nikola"'
Search Results
52. Micronized Droplets of Viral Vaccines Applied to Newly Hatched Poultry Gives the Best Immune Protection
- Author
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Mazija, Hrvoje, Gottstein, Željko, Mišković, Željko, Ragland, William L., Ervaćinović, Željka, Kičeec, Zvezdan, Stevanović, Nikola, Prukner-Radovčić, Estella, Akbay, Ruveyde, and Al-Nasser, Afaf
- Subjects
nebulization ,newcastle disease ,infectious bronchitis ,avian pox ,Marek's disease ,welfare - Abstract
Vaccination of newly hatched chicken, turkey, duck and goose already in the hatchery and achieving long lasting immunity is certainly the goal of immunoprophylaxis today. The attainment of this target is foreboded in use of micronized particles of vaccine suspension produced in an ultrasonic nebulizer. Compared to usual modes of vaccination (e.g. spray, w/v, i/m, drinking water, eye drop) small particle of vaccine suspension 2-5 μ in diameter, can reach the deepest part of respiratory system augmenting enormous the resorptive surface of the respiratory system. The specific resistance develops already after 24 hours that in cases of some disease is crucial point in immunity development. In all trials the ultrasonic nebulizer (SONOVAC® 095) was used to deliver the water suspension of different virus vaccines. The only condition to use a vaccine was its composition that avoids the foaming effect that can hinder the efficacy of nebulisation. Our best investigations example are vaccination against Marek's disease (HVT FC 126), Newcastle disease (La Sota, Ulster 2C and Queensland V4), bivalent vaccines against Newcastle disease and infectious bronchitis (La Sota or B1 + H 120) and avian pox (attenuated chicken strain). The amount of given vaccine was calculated to be one dose per bird in exposition time of 30 to 60 seconds of and was related to the type of vaccine (virus strain). Prior to antibody development the vaccinated birds should stay in hatchery for at least 24 hours before being delivered to the farms. Nebulization is an effective and safe method of specific vaccination offering welfare to poultry.
- Published
- 2013
53. Quantitative Structure-Activity Relationship Study of Some Antipsychotics by Multiple Linear Regressions
- Author
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Perušković, Danica S., Stevanović, Nikola R., Lolić, Aleksandar, Nikolić, Milan, Baošić, Rada, Perušković, Danica S., Stevanović, Nikola R., Lolić, Aleksandar, Nikolić, Milan, and Baošić, Rada
- Abstract
The retention behavior and lipophilicity parameters of some antiphychotics were determined using reversed-phase thin layer chromatography. Quantitative structure-activity relationships studies have been performed to correlate the molecular characteristics of observed compounds with their retention as well as with their chromatographically determinated lipophilicity parameters. The effect of different organic modifiers (acetone, tetrahydrofuran, and methanol) has been studied. The retention of investigated compounds decreases linearly with increasing concentration of organic modifier. The chemical structures of the antipsychotics have been characterized by molecular descriptors which are calculated from the structure and related to chromatographically determinated lipophilicity parameters by multiple linear regression analysis. This approach gives us the possibility to gain insight into factors responsible for the retention as well as lipophilicity of the investigated set of the compounds. The most prominent factors affecting lipophilicity of the investigated substances are Solubility, Energy of the highest occupied molecular orbital, and Energy of the lowest unoccupied molecular orbital. The obtained models were used for interpretation of the lipophilicity of the investigated compounds. The prediction results are in good agreement with the experimental value. This study provides good information about pharmacologically important physico-chemical parameters of observed antipsychotics relevant to variations in molecular lipophilicity and chromatographic behavior. Established QSAR models could be helpful in design of novel multitarget antipsychotic compounds.
- Published
- 2014
54. A thin layer chromatographic comparison of raw and soluble starch hydrolysis patterns of some alpha-amylases from Bacillus sp isolated in Serbia
- Author
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Gligorijević, Nikola, Stevanović, Nikola R., Lončar, Nikola L., Baošić, Rada, Vujčić, Zoran, Božić, Nataša, Gligorijević, Nikola, Stevanović, Nikola R., Lončar, Nikola L., Baošić, Rada, Vujčić, Zoran, and Božić, Nataša
- Abstract
Several natural isolates of Bacillus strains namely 5B, 12B, 16B, 18 and 24B were grown at two different temperatures in submerged fermentation for the production of raw-starch-digesting alpha-amylases. All strains except Bacillus sp. 18 produced more alpha-amylase at 37 degrees C. The hydrolysis of raw cornstarch followed the same pattern. Efficient hydrolysis was obtained with alpha-amylases from Bacillus sp. 5B, 12B, 16B and 24B grown at 37 degrees C and Bacillus sp. 18 grown at 50 degrees C. Zymography after isoelectric focusing showed that alpha-amylases were produced in multiple forms, from 2 to 6, depending on the strain when they were growing at 37 degrees C, while growth at 50 degrees C induced only 1 or 2 isoforms. Thin layer chromatography (TLC) analysis of the hydrolysis products of raw corn and soluble starch by alpha-amylases revealed the 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 the obtained alpha-amylases could be used for starch liquidification or short-chain-oligosaccharide formation, depending on the type of starch (raw or soluble) used for the hydrolysis.
- Published
- 2014
55. Imunogenost cjepnog soja FC 126 protiv Marekove bolesti i cjepnog virusa boginja peradi danih istodobno postupkom nebulizacije netom izleženim pilićima
- Author
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Stevanović, Nikola
- Subjects
Marekova bolest ,boginje peradi ,HVP FC 126 ,nebulizacija ,imunogenost - Abstract
Istražen je učinak bilo samostalnog ili istodobnog davanja cjepiva protiv Marekove bolesti (MB) i virusa boginja peradi(BP) postupkom nebulizacije netom izleženim pilićima. Pokus je proveden na 550 muških pilića lakih hibrida, podijeljenih u pet skupina po 110 pilića. Skupina A cijepljena je istodobno protiv MB i BP, postupkom nebulizacije kroz 30 sekundi. Kako bi se dokazala neškodljivost prethodno navedenog postupka skupina A1 cijepljena je istom mješavinom cjepiva tijekom 300 sekundi. Skupina B je cijepljena protiv BP primijenom cjepiva postupkom nebulizacije, 30 sekundi, a nad skupinom C proveden je istovjetni postupak, ali s cjepivom protiv MB. Skupina K tretirana je destiliranom vodom, primjenom nebulizacije kroz 30 sekundi. U dobi 1, 3, 5, 7, 14, 28, 35 i 42 dana pretraženi su uzorci tkiva pluća, koštane srži te leukociti probom PCR u stvarnom vremenu, a također u dobi 16 dana cijepljeni su protiv NB odnosno ZBB u dobi 20 dana. Pri samostalnom davanju cjepiva protiv BP, DNK VBP dokazana je u maloj količini u plućima, ali ne i u koštanoj srži što se pripisuje imunomodulirajućem učinku danog cjepiva protiv MB. Istodobno davanje virus MB i virusa BP potiče specifičnu imunost protiv BP što je dokazano izazivačkom infekcijom u dobi od 42 dana, a protiv MB nalazom DNK u leukocitima, odnosno koštanoj srži cijepljenih pilića. Postupak je moguće koristiti i u proizvodnoj praksi.
- Published
- 2008
56. Effect of substituents on prediction of TLC retention of tetra-dentate Schiff bases and their Copper(II) and Nickel(II) complexes.
- Author
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Stevanović, Nikola R., Perušković, Danica S., Gašić, Uroš M., Antunović, Vesna R., Lolić, Aleksandar Đ., and Baošić, Rada M.
- Abstract
The objectives of this study were to gain insights into structure-retention relationships and to propose the model to estimating their retention. Chromatographic investigation of series of 36 Schiff bases and their copper(II) and nickel(II) complexes was performed under both normal- and reverse-phase conditions. Chemical structures of the compounds were characterized by molecular descriptors which are calculated from the structure and related to the chromatographic retention parameters by multiple linear regression analysis. Effects of chelation on retention parameters of investigated compounds, under normal- and reverse-phase chromatographic conditions, were analyzed by principal component analysis, quantitative structure-retention relationship and quantitative structure-activity relationship models were developed on the basis of theoretical molecular descriptors, calculated exclusively from molecular structure, and parameters of retention and lipophilicity. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
57. Influence of organic modifiers on RP-TLC determination of lipophilicity of some polydentate Schiff bases
- Author
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Perušković, Danica S., primary, Darić, Branka, additional, Blagus, Anita, additional, Stevanović, Nikola R., additional, Pavlović, Aleksandra V., additional, Lolić, Aleksandar Đ., additional, and Baošić, Rada M., additional
- Published
- 2014
- Full Text
- View/download PDF
58. Quantitative Structure-Activity Relationship Study of Some Antipsychotics by Multiple Linear Regressions
- Author
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Perušković, Danica S., primary, Stevanović, Nikola R., additional, Lolić, Aleksandar Đ., additional, Nikolić, Milan R., additional, and Baošić, Rada M., additional
- Published
- 2014
- Full Text
- View/download PDF
59. Effects of motivation on performance of students in MOOC
- Author
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Stevanović, Nikola, primary
- Published
- 2014
- Full Text
- View/download PDF
60. Influence of the Structure on the Antioxidant Activity of Tetradentate Schiff Bases and their Copper(II) Complexes: Possible Mechanisms
- Author
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Aburas, Najat M., Stevanović, Nikola R., Milčić, Miloš K., Lolić, Aleksandar, Natić, Maja, Tešić, Živoslav Lj., Baošić, Rada, Aburas, Najat M., Stevanović, Nikola R., Milčić, Miloš K., Lolić, Aleksandar, Natić, Maja, Tešić, Živoslav Lj., and Baošić, Rada
- Abstract
The influence of the structure on the antioxidant activity of a series of Schiff bases and their copper(II) complexes as well as possible mechanisms of antioxidant activity were investigated. Schiff bases are derived from the condensation of ethane-1,2-diamine or propane-1,2-diamine and pentane-2,4-dione and/or 1-phenylbutane-1,3-dione. The corresponding complexes were synthesized. The antioxidant activity in vitro, determined using reversed-phase thin layer chromatography assay (RP TLC) based on the reaction with 2,2'-diphenyl-1-picrylhydrazyl, was expressed as Trolox equivalent antioxidant capacity (TEAC). The influence of the structure was observed on the basis of interpretable and informative descriptors calculated by hybrid density functional theory (DFT) methods. Structural features responsible for the antioxidant activity of the investigated compounds were discussed. Copper(II) complexes showed a significantly higher antioxidant activity than their corresponding ligands. Calculated quantum-chemical descriptors gave an insight to the reaction mechanism of the scavenging/antioxidant activity of tetradentate Schiff bases and their copper(II) complexes and two different reaction mechanisms were proposed.
- Published
- 2013
61. Electrochemical behavior and antioxidant activity of tetradentate Schiff bases and their copper(II) complexes
- Author
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Aburas, Najat M., Lolić, Aleksandar, Stevanović, Nikola R., Tripkovic, Tatjana, Nikolić-Mandić, Snežana D., Baošić, Rada, Aburas, Najat M., Lolić, Aleksandar, Stevanović, Nikola R., Tripkovic, Tatjana, Nikolić-Mandić, Snežana D., and Baošić, Rada
- Abstract
This study describes the effects of the substituents on electrochemical behavior and antioxidant activity of the six tetradentate Schiff bases, containing ethane-1,2-diamine or propane-1,2-diamine as the amine part and pentane-2,4-dione and/or 1-phenylbutane-1,3-dione as beta-diketone, and corresponding copper(II) complexes. Cyclic voltammograms of these compounds were recorded in dimethylsulfoxide and 0.1 M sodium perchlorate as supporting electrolyte with glassy carbon as working electrode at different scan rates. The voltammograms of Schiff bases alone showed only one irreversible peak. Voltammograms recorded for complexes showed the presence of quasi-reversible processes taking place at the metal center and reversible process at the ligand part. Both steric and inductive effects of substituents and structure of imine bridge of Schiff base ligands as well as complexes were discussed. These effects appear relevant for the antioxidant activity. Antioxidant activity of the investigated compounds expressed as Trolox equivalent antioxidant capacity is also discussed. The electrochemical behavior showed a high correlation with the antioxidant activity for investigated compounds.
- Published
- 2012
62. Influence of the Structure on the Antioxidant Activity of Tetradentate Schiff Bases and their Copper(II) Complexes: Possible Mechanisms
- Author
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Aburas, Najat M., primary, Stevanović, Nikola R., additional, Milčić, Miloš K., additional, Đ. Lolić, Aleksandar, additional, Natić, Maja M., additional, Tešić, Živoslav Lj., additional, and Baošić, Rada M., additional
- Published
- 2013
- Full Text
- View/download PDF
63. EFFECTS OF MOTIVATION ON PERFORMANCE OF STUDENTS IN MOOC.
- Author
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Stevanović, Nikola
- Subjects
ACADEMIC motivation ,DISTANCE education ,RATING of students ,ONLINE education - Abstract
The paper is based on the view that avid number of students enrolled in online courses doesn't necessarily finish them and earn certificate. Specialized web sites such as Coursera, EdX and Udacity are getting more members each day, but number of people who attend courses is not getting higher. Question that was asked is what is motivational factor for people to enroll in these courses and what keeps them focused and oriented toward finishing them. The premise is that reason for engagement in online courses comes mainly from external factor i.e. expectations of subject social environment. This paper discuss differences between external and internal motivational factors, with emphasis on self-determination which subjects shows in early weeks of attendance these courses, and which declines as the course proceeds toward the end and final exam which leads to receiving certificate. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
64. MESTO SPORTSKO-REKREATIVNOG INTERESOVANJA UČENIKA 7. RAZREDA U FAKTORSKOJ ANALIZI RAZLIČITIH INTERESOVANJA.
- Author
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Milošević, Vladimir, Petrović, Adam, and Stevanović, Nikola
- Subjects
INTEREST (Psychology) ,PSYCHOLOGY of students ,SCHOOL sports ,STUDENT recreation ,PHYSICAL education research - Abstract
Personal interests carry a great potential and are usually a drive to act. Therefore they usually point towards the activity of an individual in his interest area. An insight into the position of the interest in sports and recreation among other interests can be obtained by inspecting the interests of 7
th grade elementary school students from Sremska Mitrovica and Jagodina. The sample consisted of 736 7th grade elementary school students of both genders. A non-experimental study of the students' interests was done using a questionnaire that consisted of 5 interest indicators: job preference, self-estimation of affinity, use of free time, direct self-estimation of interests and reaction to key words-stimuli. Each indicator had 30 items that asses 30 interests. A t test was used to inspect the level of interest in sports and recreation. Also, factor analysis was done for each indicator separately. The reason for this approach is that there is no real confirmation that these 5 indicators are well suited for assessing the interests of young persons in the time we live in. Students' interest in sports and recreation is about 4 on the scale of 1 to 5, on each of the indicators. The data shows that the interest of 7th grade elementary school students in sports and recreation is closely linked to interest in military, these two interests belong to the same factor regardless of the way the interests are assessed, that is, they belong to the same factor on each of the 5 indicators. The interest in adventure belongs to the same factor as the interest in sports and recreation on 4 out of 5 indicators, and interest in humor, interest in travel and hedonistic interest on 3 out of 5 indicators. These results might indicate that the motives for engaging in sports and recreation are unstable, because this composition of relatedness of the interests can be interpreted as the factor of fun. If that is so, these findings alert to the importance of building a system of human values in which the physical education, taken in a broader sense, will have a significant place. A high level of students' interest in sports and education is a good starting point for reflecting upon the practice in the system of physical education and the system of sports of young persons. However, we must bear in mind the structure of interests. Professionals in the physical education area are obligated by the interests' value orientation to positively influence the youth. [ABSTRACT FROM AUTHOR]- Published
- 2013
65. Merenje i upravljanje profitabilnošću kupaca
- Author
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Pobrić, Amira R., Malinić, Dejan, Milićević, Vlade, Veljković, Saša, and Stevanović, Nikola
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profitabilnost kupaca ,customer relationship management ,kreiranje vrednosti ,vrednovanje kupaca ,value creation ,customer accounting ,customer valuation ,Customer Profitability ,računovodstvo kupaca ,upravljanje odnosima sa kupcima - Abstract
Stvaranje vrednosti za vlasnike predstavlja primarni cilj svake profitno orijentisane organizacije. Da bi se ostvario ovaj cilj potrebno je istovremeno zadovoljiti interese i ostalih stejkholdera, s tim da interesi različitih stejkholdera mogu biti međusobno suprotstavljeni, što otežava upravljanje preduzećem i njegovo usmeravanje ka ostvarenju željenih performansi. Pored interesa, različiti stejkholderi imaju različit značaj, moć i na raspolaganju različite instrumente za vršenje pritiska na preduzeće, ali po značaju i moći kupci i vlasnici se mogu staviti u istu ravan. Stvaranje vrednosti za kupce i za vlasnike je direktno uslovljeno i povezano. Stvoriti vrednost za vlasnike znači kreirati odgovarajući neto novčani tok iz kojeg će se isplatiti dividende i koji će osigurati sticanje kapitalnih dobitaka, pri čemu su kupci jedini stejkholderi koji kroz kupovinu proizvoda i usluga obezbeđuju preduzeću prihode i novčane prilive. Do kupovina proizvoda i usluga od strane kupaca, na kontinuiranoj osnovi, doći će samo ako su zadovoljeni njihovi interesi, odnosno ako je stvorena vrednost za njih, s tim da stvaranje vrednosti za kupce izaziva preduzeću troškove i novčane odlive, koji u slučaju neadekvatnog upravljanja mogu da premaše kreirane prihode odnosno novčane prilive. Iz toga sledi da je stvaranje vrednosti za kupce neophodan preduslov za stvaranje vrednosti za vlasnike, ali da stvorena vrednost za kupce ne garantuje da će biti stvorena i vrednost za vlasnike. Istovremeno uvažavanje interesa i kupaca i vlasnika moguće je postići kroz upravljanje profitabilnošću kupaca. Profitabilnost kupaca pokazuje da li je i u kojoj meri vrednost koja je isporučena kupcima transformisana u vrednost za vlasnike. Nije moguće postići profitabilnost kupaca ako prethodno nije stvorena vrednost za kupce, i nije moguće stvoriti dodatu vrednosti za vlasnike ako kupci nisu stvorili profit za preduzeće. Svaki kupac ne doprinosi podjednako profitabilnosti preduzeća. Obično, mali broj kupaca generiše velike dobitke ili velike gubitke, a najveći broj kupaca značajnije ne utiče na nivo profitabilnosti preduzeća. Creating value for owners is the primary goal of any profit oriented organization. In order to achieve this goal, company have to simultaneously satisfy the interests of all stakeholders. Different stakeholders have different interests which can be conflicted and it makes difficult to manage the company and to accomplish the desired performance. Different stakeholders also have different level of significance, power and available instruments for doing pressure on the company, but according to importance and power, owners and customers can be put on the same level. Creating value for customers and owners is directly conditioned and connected. Creating value for owners implies creating of the appropriate net cash flow from which will be paid dividends and ensured capital gains. Customers are the only stakeholders who through the purchase of products and services provide revenue and cash inflow to the company. They will buy products and services on a continuous basis only if their interests are satisfied, i.e. if company create value for them. At the same time, creating customer value produces cost and cash outflow to the company. In case of bad customer relationship management, that cost might be bigger than revenue which customers create for the company. Hence creating customer value is essential precondition for creating owner value, but created customer value does not guarantee that will be created the value for the owners. The interests of customers and owners can be simultaneously respected through customer profitability management. Customer profitability indicates whether and to what extent the value that is delivered to the customers are transformed into value for the owners. It is not possible to achieve customer profitability if value for customers is not previously created and it is not possible to create owner value if customers did not previously create profit for the company. Each customer does not contribute equally to the profitability of the company. It is common to find that a small number of customers generate large gains or large losses, while the rest does not significantly affect the level of company’s profitability.
- Published
- 2016
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