Antimutagenic, Antirecombinogenic, and Antitumor Effect of Amygdalin in a Yeast Cell–Based Test and Mammalian Cell Lines

Atanaska Todorova,Margarita Pesheva,Ivan Iliev,Krum Bardarov,Teodora Todorova 한국식품영양과학회 2017 Journal of medicinal food Vol.20 No.4

Amygdalin is a major component of the seeds of Rosaceae family of plants such as apricots, peaches, cherry, nectarines, apples, plums, and so on, as well as almonds. It is used in alternative medicine for cancer prevention, alleviation of fever, cough suppression, and quenching thirst. The aim of the present study is to determine the mutagenic and recombinogenic effects of amygdalin in a test system Saccharomyces cerevisiae and to evaluate its potential antitumor effect in a yeast cell–based test and colon cancer cell lines. Results obtained show that concentrations 25, 50, and 100 μg/mL did not have any cytotoxic, mutagenic, and carcinogenic effect in yeast cell–based tests. Pretreatment with amygdalin at concentration 100 μg/mL leads to around twofold of the cell survival and decrease of reverse mutation frequency, induced by the alkylating agent methyl methanesulfonate. The frequency of gene conversion and mitotic crossing-over is around threefold lower. The anticarcinogenic potential of amygdalin at the same concentration is presented as around fourfold reduction of Ty1 retrotransposition induced by hexavalent chromium. In summary, data presented in this study provide evidence concerning the inability of amygdalin itself to provoke events related to the initial steps of tumorigenesis. In addition, the observed antimutagenic/antirecombinogenic effect could be activation of error-free and error-prone recombination events. Based on the high selectivity toward normal or tumor cell lines, it could be speculated that amygdalin has higher cytotoxic effect in cell lines with higher proliferative and metabolic activity, which are the majority of fast developing tumors.

Antioxidant, Antimutagenic, and Anticarcinogenic Effects of Papaver rhoeas L. Extract on Saccharomyces cerevisiae

Teodora Todorova,Margarita Pesheva,Fridrich Gregan,Stephka Chankova 한국식품영양과학회 2015 Journal of medicinal food Vol.18 No.4

The aim of this work was to analyze the antioxidant and antimutagenic/anticarcinogenic capacity of Papaver rhoeas L. water extract against standard mutagen/carcinogen methyl methanesulfonate (MMS) and radiomimetic zeocin (Zeo) on a test system Saccharomyces cerevisiae. The following assays were used: 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, quantitative determination of superoxide anion (antireactive oxygen species [antiROS test]), DNA topology assay, D7ts1 test—for antimutagenic—and Ty1 transposition test—for anticarcinogenic effects. Strong pro-oxidative capacity of Zeo was shown to correlate with its well-expressed mutagenic and carcinogenic properties. The mutagenic and carcinogenic effects of MMS were also confirmed. Our data concerning the antioxidant activity of P. rhoeas L. extract revealed that concentration corresponding to IC50 in the DPPH assay possessed the highest antioxidant activity in the antiROS biological assay. It was also observed that a concentration with 50% scavenging activity expressed the most pronounced antimutagenic properties decreasing Zeo-induced gene conversion twofold, reverse mutation fivefold, and total aberrations fourfold. The same concentration possessed well-expressed anticarcinogenic properties measured as reduction of MMSinduced Ty1 transposition rate fivefold and fourfold when Zeo was used as an inductor. Based on the well-expressed antioxidant, antimutagenic, and anticarcinogenic properties obtained in this work, the P. rhoeas L. extract could be recommended for further investigations and possible use as a food additive.

Service Quality and Information Value of Online Travel Chat - A Case from KTO's 1330 Chat

Petya, Todorova,Hyemin, Kim,Chulmo, Koo Smart Tourism Research Center 2022 Journal of smart tourism Vol.2 No.4

Tourism businesses use chat services to provide immediate customer support and to help users navigate within a website, but there are more outcomes of this interaction that should be examined. The current study aimed to discover if the online travel chat service quality and information value of the online travel chat service lead to user satisfaction with the service and visit intention to a recommended destination by Korea Tourism Organization's 1330 Live Chat. The results indicate that information value (functional and innovation) and online travel chat service quality (reliability, assurance, and security) lead to satisfaction with the live chat service and visit intention to a recommended destination. The results can benefit practitioners who want to expand and improve their customer service interaction and recommendations, and to scholars who study the relationship between customer services in tourism recommendation and sales context.

Correctness of the formal generalized net project of the connections between procedural program functions

Magdalina Todorova 장전수학회 2013 Proceedings of the Jangjeon mathematical society Vol.16 No.3

The article presents definitions of a formal generalized net project of theconnections between procedural program functions, correctness of this model accordingto a specification, and correspondence of the formal generalized net project of theconnections between procedural program functions with the implementation of theprogram. A theorem is formulated to define a correctness criterion of a generalized netproject of the connections between procedural program functions with respect to adefined for it specification.

On the solutions of some equations with index matrices

Stela Todorova,Veselina Bureva,Nora Angelova 장전수학회 2023 Proceedings of the Jangjeon mathematical society Vol.26 No.3

On the solutions of some equations with index matrices

Doped Sol-gel TiO₂ Films for Biological Applications

Gartner, M.,Trapalis, C.,Todorova, N.,Giannakopoulou, T.,Dobrescu, G.,Anastasescu, M.,Osiceanu, P.,Ghita, A.,Enache, M.,Dumitru, L.,Stoica, T.,Zaharescu, M.,Bae, J.Y.,Suh, S.H. Korean Chemical Society 2008 Bulletin of the Korean Chemical Society Vol.29 No.5

Mono and multilayer TiO2(Fe, $PEG_{600}$) films were deposited by the dip-coating on $SiO_2$/glass substrate using sol-gel method. In an attempt to improve the antibacterial properties of doped $TiO_2$ films, the influence of the iron oxides and polyethilenglycol ($PEG_{600}$) on the morphological, optical, surface chemical composition and biological properties of nanostructured layers was studied. Complementary measurements were performed including Spectroscopic Ellipsometry (SE), Scanning Electron Microscopy (SEM) coupled with the fractal analysis, X-Ray Photoelectron Spectroscopy (XPS) and antibacterial tests. It was found that different concentrations of Fe and $PEG_{600}$ added to coating solution strongly influence the porosity and morphology at nanometric scale related to fractal behaviour and the elemental and chemical states of the surfaces as well. The thermal treatment under oxidative atmosphere leads to films densification and oxides phase stabilization. The antibacterial activity of coatings against Escherichia Coli bacteria was examined by specific antibacterial tests.

Software protection via generalized nets

Nora Angelova,Magdalina Todorova,Daniela Orozova,Krassimir Atanassov 장전수학회 2019 Advanced Studies in Contemporary Mathematics Vol.29 No.2

In the paper is described a new method of software protection by means of Generalized Net (GN). More specifically, the paper presents a novel application of a GNs concept which is a powerful tool for the representation and handling of dynamic discrete event problems and systems. The article describes a method of software protection which combines anti-debugging and registration number protection techniques. Instead of blocking the debugging tools, the fragment that realizes registration number comparison gets more complicated and integrates a GN into the code in a uniques way. The complex mathematical apparatus of GNs is unknown and difficult to understand by crackers, which increases the reliability of the method. The reliability of the proposed method is also increased by the use of two-factor authentication. The description of the protection method is preceded by a brief introduction to the field of study and to the used apparatus of the GNs theory. The report ends with short notes on the reliability of the method.

Doped Sol-gel TiO₂Films for Biological Applications

M. Gartner*,C. Trapalis,N. Todorova,T. Giannakopoulou,G. Dobrescu,M. Anastasescu,P. Osiceanu,A. Ghita,M. Enache,L. Dumitru,T. Stoica,§ M. Zaharescu,J. Y. Bae,S.-H. Su* 대한화학회 2008 Bulletin of the Korean Chemical Society Vol.29 No.5

Mono and multilayer TiO₂(Fe, PEG600) films were deposited by the dip-coating on SiO₂/glass substrate using sol-gel method. In an attempt to improve the antibacterial properties of doped TiO₂films, the influence of the iron oxides and polyethilenglycol (PEG600) on the morphological, optical, surface chemical composition and biological properties of nanostructured layers was studied. Complementary measurements were performed including Spectroscopic Ellipsometry (SE), Scanning Electron Microscopy (SEM) coupled with the fractal analysis, X-Ray Photoelectron Spectroscopy (XPS) and antibacterial tests. It was found that different concentrations of Fe and PEG600 added to coating solution strongly influence the porosity and morphology at nanometric scale related to fractal behaviour and the elemental and chemical states of the surfaces as well. The thermal treatment under oxidative atmosphere leads to films densification and oxides phase stabilization. The antibacterial activity of coatings against Escherichia Coli bacteria was examined by specific antibacterial tests.

Synthesis, Characterization, and Application of New Reactive Triazine Dye on Cotton and Paper

Polya M. Miladinova,Dimitrina A. Todorova 한국섬유공학회 2022 Fibers and polymers Vol.23 No.6

A new orange homobifunctional triazine reactive dye was synthesized, using the dichlorotriazine reactive dye withthe same chromophore. The homobifunctional and dichlorotriazine dyes were evaluated on textile and paper. The degree ofexhaustion, fixation, and the fastness properties of dyed cotton samples of washing, acidic and alkaline perspiration, dry andwet rubbing were assessed. Dyes were used in the composition of offset printing paper with a fiber content of bleachedsoftwood and hardwood pulp in a ratio of 1:1. The paper was sized with alkyl ketene dimer and natural calcium carbonatewas used as a filler. The main strength and hydrophobic properties of the dyed papers were examined. The optical properties- L*, a*, b*, C*, and h* from the CIE Lab color space of the resulting paper and textile samples have been examined. As a resultof the studies carried out it was found out that with both reactive dyes, paper and textile samples with similar color shades,uniform coloring, and stable color were obtained. With respect to the complex of the examined strength, capillary, and opticalproperties, better results were obtained with homobifunctional reactive triazine dye.

Estimation of Net Ecosystem Metabolism of Seagrass Meadows in the Coastal Waters of the East Sea and Black Sea using the Noninvasive Eddy Covariance Technique

이재성,강동진,Elitsa Hineva,Violeta Slabakova,Valentina Todorova,박지영,조진형 한국해양과학기술원 2017 Ocean science journal Vol.52 No.2

We measured the community-scale metabolism of seagrass meadows in Bulgaria (Byala [BY]) and Korea (Hoopo Bay [HP]) to understand their ecosystem function in coastal waters. A noninvasive in situ eddy covariance technique was applied to estimate net O2 flux in the seagrass meadows. From the highquality and high-resolution time series O2 data acquired over > 24 h, the O2 flux driven by turbulence was extracted at 15-min intervals. The spectrum analysis of vertical flow velocity and O2 concentration clearly showed well-developed turbulence characteristics in the inertial subrange region. The hourly averaged net O2 fluxes per day ranged from -474 to 326 mmol O2 m-2 d-1 (-19 ± 41 mmol O2 m-2 d-1) at BY and from -74 to 482 mmol O2 m-2 d-1 (31 ± 17 mmol O2 m-2 d-1) at HP. The net O2 production rapidly responded to photosynthetically available radiation (PAR) and showed a good relationship between production and irradiance (P-I curve). The hysteresis pattern of P-I relationships during daytime also suggested increasing heterotrophic respiration in the afternoon. With the flow velocity between 3.30 and 6.70 cm s-1, the community metabolism during daytime and nighttime was significantly increased by 20 times and 5 times, respectively. The local hydrodynamic characteristics may be vital to determining the efficiency of community photosynthesis. The net ecosystem metabolism at BY was estimated to be -17 mmol O2 m-2 d-1, which was assessed as heterotrophy. However, that at HP was 36 mmol O2 m-2 d-1, which suggested an autotrophic state.