Time filter

Source Type

Seoul, South Korea

Vitorovic-Todorovic M.D.,Military Technical Institute Belgrade | Eric-Nikolic A.,Serbian Institute for Oncology and Radiology of Serbia | Kolundzija B.,Serbian Institute for Oncology and Radiology of Serbia | Hamel E.,Frederick National Laboratory for Cancer Research | And 3 more authors.
European Journal of Medicinal Chemistry

Antiproliferative activity of twenty-nine (E)-4-aryl-4-oxo-2-butenoic acid amides against three human tumor cell lines (HeLa, FemX, and K562) is reported. Compounds showed antiproliferative activity in one-digit micromolar to submicromolar concentrations. The most active derivatives toward all the cell lines tested bear alkyl substituents on the aroyl moiety of the molecules. Fourteen compounds showed tubulin assembly inhibition at concentrations <20 μM. The most potent inhibitor of tubulin assembly was unsubstituted compound 1, with IC50 = 2.9 μM. Compound 23 had an oral LD50 in vivo of 45 mg/kg in mice. Cell cycle analysis on K562 cells showed that compounds 1, 2 and 23 caused accumulation of cells in the G2/M phase, but inhibition of microtubule polymerization is not the principal mode of action of the compounds. Nevertheless, they may be useful leads for the design of a new class of antitubulin agents. © 2012 Elsevier Masson SAS. All rights reserved. Source

Ivic B.,RandD Institute | Betz G.,University of Basel
Archives of Pharmacal Research

The purpose of this study was development of diclofenac sodium extended release compressed matrix pellets and optimization using Generalized Regression Neural Network (GRNN). According to Central Composite Design (CCD), ten formulations of diclofenac sodium matrix tablets were prepared. Extended release of diclofenac sodium was acomplished using Carbopol® 71G as matrix substance. The process of direct pelletisation and subsequently compression of the pellets into MUPS tablets was applied in order to investigate a different approach in formulation of matrix systems and to achieve more control of the process factors over the principal response - the release of the drug. The investigated factors were X1 -the percentage of polymer Carbopol® 71 G and X2- crushing strength of the MUPS tablet. In vitro dissolution time profiles at 5 different sampling times were chosen as responses. Results of drug release studies indicate that drug release rates vary between different formulations, with a range of 1 hour to 8 hours of dissolution. The most important impact on the drug release has factor X 1 -the percentage of polymer Carbopol® 71 G. The purpose of the applied GRNN was to model the effects of these two causal factors on the in vitro release profile of the diclofenac sodium from compressed matrix pellets. The aim of the study was to optimize drug release in manner wich enables following in vitro release of diclofenac sodium during 8 hours in phosphate buffer: 1 h: 15-40%, 2 h: 25-60%, 4 h: 35-75%, 8 h: >70%. © 2010 The Pharmaceutical Society of Korea and Springer Netherlands. Source

Ahmed Z.,King Abdulaziz University | Kim S.-M.,Kangwon National University | Kim I.S.,Gwangju Institute of Science and Technology | Bum M.-S.,Korea Water Resources Corporation | And 4 more authors.
Environmental Technology (United Kingdom)

A pilot-scale municipal wastewater treatment plant composed of a fixed film activated sludge (IFAS) system with sulfur-limestone autotrophic denitrification (SLAD) was operated for a year and the influence of different operational factors was investigated. Nitrification efficiency was found to be above 91% at temperatures above 25°C even at short hydraulic residence times (HRTs), but declined to 51 ± 2% when the temperature dropped to 22 ± 3°C. The minimum HRT (HRT min) to achieve nitrification efficiency > 90% was found to be 12 h at temperatures above 25°C. Denitrification efficiencies were found to be 89% and 79% at a nitrate loading of 0.36 kg NO - 3 -Nm -3 d -1 and at 0.18kg NO - 3-Nm -3 d -1, respectively. The minimum empty bed residence time (EBRT) to achieve denitrification efficiency above 80% without methanol addition was 3h at a nitrate loading rate of 0.27-0.38kg NO - 3-Nm -3 d -1. The amount of nitrate removed as a function of the sulfate formed was found to be 0.188g NO - 3-N/g SO 2- 4. The nitrate load removed by the biofilter as a function of the alkalinity consumed was found to be very close to the theoretical stoichiometric value. The application of the pilot plant was proven to be feasible and the performance of the SLAD system, especially with respect to the minimum EBRT to achieve denitrification efficiency above 80%, the maximum denitrification rate and performance at temperatures below 10°C. To achieve a nitrification efficiency above 90% in the IFAS system, temperature changes and the minimum HRT were found to be the most influential operational parameters. © 2012 Taylor & Francis. Source

Zukovec Topalovic D.,University of Belgrade | Zivkovic L.,University of Belgrade | Cabarkapa A.,University of Belgrade | Djelic N.,University of Belgrade | And 3 more authors.
Oxidative Medicine and Cellular Longevity

The thyroid hormones change the rate of basal metabolism, modulating the consumption of oxygen and causing production of reactive oxygen species, which leads to the development of oxidative stress and DNA strand breaks. Olive (Olea europaea L.) leaf contains many potentially bioactive compounds, making it one of the most potent natural antioxidants. The objective of this study was to evaluate the genotoxicity of L-thyroxine and to investigate antioxidative and antigenotoxic potential of the standardized oleuropein-rich dry olive leaf extract (DOLE) against hydrogen peroxide and L-thyroxine-induced DNA damage in human peripheral blood leukocytes by using the comet assay. Various concentrations of the extract were tested with both DNA damage inducers, under two different experimental conditions, pretreatment and posttreatment. Results indicate that L-thyroxine exhibited genotoxic effect and that DOLE displayed protective effect against thyroxine-induced genotoxicity. The number of cells with DNA damage, was significantly reduced, in both pretreated and posttreated samples (P < 0.05). Comparing the beneficial effect of all tested concentrations of DOLE, in both experimental protocols, it appears that extract was more effective in reducing DNA damage in the pretreatment, exhibiting protective role against L-thyroxine effect. This feature of DOLE can be explained by its capacity to act as potent free radical scavenger. © 2015 Dijana Žukovec Topalović et al. Source

Chung I.,Yeungnam University | Lee M.,RandD Institute
Nuclear Engineering and Design

A fretting wear test rig employing a piezoelectric actuator has been developed, which is equipped with a heating and water circulation system. The fretting wear tests of cross-contacting Inconel 690 tubes, which is widely used for power plant steam generator, have been carried out in room temperature ambient and 80 °C in-water conditions. Maximum normal load was 55 N, and the sliding amplitude was below 50 μm. Scars of the mixed-slip and the gross-slip fretting wear have been measured in terms of scar diameter and wear volume. From the relationship between the work rate and the wear rate, a threshold of work rate has been defined, and this is found to be closely related with fretting wear regimes. The wear coefficients have been evaluated in the gross-slip regime. Distinct fretting wear mechanisms have been observed for the two different test conditions from SEM microphotographs. The crack formation, large particle separation and resulting third body effect were significant in room temperature ambient condition. The protective nature of the tribologically transformed layers coupled with non-uniform contact results in the lower wear coefficient while smooth wear scar and extensive abrasion produces higher wear volume in the other condition. © 2011 Elsevier B.V. All rights reserved. Source

Discover hidden collaborations