Jovic M.,University of Belgrade |
Milutinovic D.,Hemofarm Group |
Kos A.,University of Ljubljana |
Tomazic S.,University of Ljubljana
Journal of Universal Computer Science | Year: 2012
This paper deals with customers' behavior in an online environment. The major hypothesis of this paper is that different online product presentation strategies have a different impact on the customer's choice and that this impact can be measured. The research was conducted using an experimental method based on 6 product groups of 8 products per group. The products were presented with different combinations of several audio and visual elements: text, picture, video, animation, speech, special sound, and background music. The impact of each combination on the customer's choice was tested on a customer sample of 46 examinees. The most important conclusion is that besides text and a picture of the product, it is highly recommendable to include a video of the product in the product's online presentation. Regarding the number of multimedia elements, it is better to include more than less elements in a product presentation on the Internet, in contrast to some findings in connection with e-Learning.© J.UCS.
Organophosphorus insecticides: Toxic effects and bioanalytical tests for evaluating toxicity during degradation processes [Organofosfatni insekticidi: Toksični efekti i bioanalitički testovi za evaluaciju toksičnosti tokom procesa degradacije]
Colovic M.B.,Vinča Institute of Nuclear Sciences |
Krstic D.Z.,University of Belgrade |
Vasic V.M.,Vinča Institute of Nuclear Sciences |
Bondzic A.M.,Vinča Institute of Nuclear Sciences |
And 3 more authors.
Hemijska Industrija | Year: 2013
Organophosphorus insecticides have been the most applied group of insectcides for the last two decades. Their main toxic effects are related to irreversible inactivation of acetylcholinesterase (AChE). Actually, they covalently bind to serine OH group in the enzyme active site forming phosphorylated enzyme that cannot hydrolyze acetylcholine. Organophosphorus insecticides in the environment undergo the natural degradation pathway including mainly homogeneous and heterogeneous hydrolysis (especially at high pH) generating non-inhibiting products. Additionally, thio organophosphates are easily oxidized by naturally present oxidants and UV light, forming more toxic and stable oxons. Thus, oxidative degradation procedures, generally referred as advanced oxidation processes (AOP), have been applied for their efficient removal from contaminated waters. The most applied bioassays to monitor the organophosphate toxicity, i.e., the detoxification degree during AOP are Vibrio fischeri and AChE bioassays. Vibrio fischeri toxicity test exploits bioluminescence as the measure of luciferase activity of this marine bacterium, whereas AChE bioassay is based on AChE activity inhibition. Both bioanalytical techniques are rapid (several minutes), simple, sensitive and reproducible. Vibrio fischeri test seems to be a versatile indicator of toxic compounds generated in AOP for organophosphorus insecticides degradation. However, detection of neurotoxic AChE inhibitors, which can be formed in AOP of some organophosphates, requires AChE bioassays. Therefore, AChE toxicity test is more appropriate for monitoring the degradation processes of thio organophosphates, because more toxic oxo organophosphates might be formed and overlooked by Vibrio fischeri bioluminescence inhibition. In addition, during organophosphates removal by AOP, compounds with strong genotoxic potential may be formed, which cannot be detected by standard toxicity tests. For this reason, determination of incidence of micronuclei and cell proliferation index in cultivated human lymphocytes and fibroblasts is suitable for evaluation of organophosphorus insecticides and their break down products inducing cytogenetic damage.
Vastag D.,University of Novi Sad |
Perisic-Janjic N.,University of Novi Sad |
Tomic J.,University of Belgrade |
Petrovic S.,University of Belgrade |
Petrovic S.,Hemofarm Group
Journal of Planar Chromatography - Modern TLC | Year: 2011
The chromatographic behavior of N-cyclohexyl-N-substituted-2- phenylacetamides was investigated using reversed phase thin-layer chromatography (RP-TLC). RP-TLC was performed on a C-18 bonded phase with different aqueous eluents: water-acetone, water-acetonitrile and water-dioxane. Linear relationship between retention parameters and organic modifier content in the mobile phase allows the extrapolation procedure. From results, it is evident that retention behavior of investigated compound depended on structures of substituents R. The correlation between the chromatographic lipophilic parameters (RM0) and calculated log P values and several pharmacokinetics parameters such as HIA (human intestinal absorption) predictor, the plasma protein binding (PB) predictor, and partition predictor for predicting the biological activity of the blood-brain barrier (BBB) has been studied. The results show that reversed-phase RM0 proved to express lipophilic nature of investigated compounds as well as biological activity. © Akadémiai Kiadó, Budapest.
Oxidative stabilisation of sunflower oil by antioxidant fractions from selected Lamiaceae herbs [Oksidativna stabilizacija suncokretovog ulja sa antioksidativnim frakcijama iz odabranih biljaka familije Lamiaceae]
Babovic N.,University of Belgrade |
Babovic N.,Singidunum University |
Zizovic I.,University of Belgrade |
Saicic S.,Serbian Institute of Meat Hygiene and Technology |
And 2 more authors.
Chemical Industry and Chemical Engineering Quarterly | Year: 2010
This study reports the effect of antioxidant fractions from rosemary (Rosmarinus officinalis), sage (Salvia officinalis), thyme (Thymus vulgaris) and hyssop (Hyssop officinalis) on the oxidative stability of sunflower oil at elevated temperature. In order to isolate antioxidant fractions, the method of fractional supercritical extraction with carbon dioxide at 35 MPa and 100 °C was applied. Antioxidant fractions were added to sunflower oil at concentrations of 200 mg/kg oil and the samples were stored in an oven maintained at 98 °C. The antioxidant activity of the extracts was determined by measuring peroxide values (PV). Among investigated extracts, the rosemary extract was most effective on retarding lipid oxidation of sunflower oil. The antioxidant activity of the extracts was compared to the activity of butylated hydroxyanisole (BHA) and a commercial rosemary extract Flavor' Plus. On the basis of PV assay, the antioxidant activity of the investigated plant extracts after 12 h of storage at 98 °C followed the order: rosemary extract > BHA > sage extract > Flavor' Plus > thyme extract > hyssop extract.
Babovic N.,University of Belgrade |
Babovic N.,Singidunum University |
Djilas S.,University of Novi Sad |
Jadranin M.,Serbian Institute of Chemistry |
And 5 more authors.
Innovative Food Science and Emerging Technologies | Year: 2010
Antioxidant fractions from four herb spices belonging to the Lamiaceae family: rosemary (Rosmarinus officinalis), sage (Salvia officinalis), thyme (Thymus vulgaris) and hyssop (Hyssop officinalis) were isolated using supercritical CO2 at 35 MPa and 100 °C. The antioxidant fractions were characterized chemically by HPLC-DAD/ESI-ToF-MS. Antioxidant activity of obtained extracts was determined by measuring their ability to scavenge stable 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical and reactive hydroxyl radical during the Fenton reaction trapped by 5,5-dimethyl-1-pyroline-N-oxide (DMPO), using electron spin resonance (ESR) spectroscopy. The antioxidant activity of the extracts was compared to the activity of butylated hydroxyanisole (BHA) and Flavor' Plus™ water-soluble rosemary extract. In DPPH radical assay the order from the strongest to the weakest antioxidant activity was: BHA, thyme extract, Flavor' Plus™, rosemary and sage extracts, and hyssop extract, while in hydroxyl radical assay order was: Flavor' Plus™, sage extract, rosemary extract, hyssop extract, BHA and thyme extract. Industrial relevance: Spices and herbs have been used not only for flavoring food but also for improving the overall quality of the product and to extend the shelf-life of foods. The present investigation relates to the field of food additives, and particularly to an antioxidant fractions from four herb spices which belong to the Lamiaceae family: rosemary (Rosmarinus officinalis), sage (Salvia officinalis), thyme (Thymus vulgaris) and hyssop (Hyssop officinalis). Butylated hydroxyanisole (BHA) and Flavor' Plus™ are used in food industry as antioxidants due to their ability to prolong the shelf-life of foodstuffs by protecting them against deterioration caused by oxidation, such as fat rancidity, colour changes, degradation of the flavor and loss of nutrient value. Synthetic antioxidants such as BHA now being replaced by natural antioxidants because of their possible toxicity and due to a suspected action as promoters of carcinogens. The present study confirms that investigated herb spices belonging to the Lamiaceae family present important sources for the production of food additives. © 2009 Elsevier Ltd. All rights reserved.
Mihailovic D.T.,University of Novi Sad |
Lazic J.,Hemofarm Group |
Lesny J.,University of Life Sciences in Poznań |
Olejnik J.,University of Life Sciences in Poznań |
And 3 more authors.
Theoretical and Applied Climatology | Year: 2010
Numerical simulations and tests with the recently redesigned land-air parameterization scheme (LAPS) are presented. In all experiments, supported either by one-point micrometeorological, 1D or 3D simulations, the attention has been directed to: (1) comparison of simulation outputs, expressing the energy transfer over and through heterogeneous and non-heterogeneous surfaces, versus observations and (2) analysis of uncertainties occurring in the solution of the energy balance equation at the land-air interface. To check the proposed method for aggregation of albedo, "propagating hole" sensitivity tests with LAPS over a sandstone rock grid cell have been performed with the forcing meteorological data for July 17, 1999 in Baxter site, Philadelphia (USA). Micrometeorological and biophysical measurements from the surface experiments conducted over crops and apple orchard in Serbia, Poland, Austria and France were used to test the operation of LAPS in calculating surface fluxes and canopy environment temperatures within and above plant covers of different densities. In addition, sensitivity tests with single canopy covers over the Central Europe region and comparison against the observations taken from SYNOP data using 3D simulations were made. Validation of LAPS performances over a solid surface has been done by comparison of 2 m air temperature observations against 5-day simulations over the Sahara Desert rocky ground using 3D model. To examine how realistically the LAPS simulates surface processes over a heterogeneous surface, we compared the air temperature measured at 2 m and that predicted by the 1D model with the LAPS as the surface scheme. Finally, the scheme behaviour over urban surface was tested by runs over different parts of a hypothetical urban area. The corresponding 1D simulations were carried out with an imposed meteorological dataset collected during HAPEX-MOBILHY experiment at Caumont (France). The quantities predicted by the LAPS compare well with the observations and the various subcomponents of the scheme appear to operate realistically. © Springer-Verlag 2009.