Bulgarian Academy Of Sciences Research Articles

Business Modeling of the Application Architecture of the Bulgarian Folklore Artery

In an attempt to answer the need of wider accessibility and popularization of the treasury of Bulgarian folklore, a team from the Institute of Mathematics and Informatics at the Bulgarian Academy of Sciences has planned to develop the Bulgarian folklore artery within the national project ―Knowledge Technologies for Creation of Digital Presentation and Significant Repositories of Folklore Heritage‖. This paper presents the process of business modeling of the application architecture of the Bulgarian folklore artery, which aids requirements analysis, application design and its software implementation. The folklore domain process model is made in the context of the target social applications — e-learning, virtual expositions of folklore artifacts, research, news, cultural/ethno-tourism, etc. The basic processes are analyzed and modeled and some inferences are made for the use cases and requirements specification of the Bulgarian folklore artery application. As a conclusion the application architecture of the Bulgarian folklore artery is presented.

Determination of human interferon-gamma in the transgenic mice milk by modified Kynurenine bioassay test

Adiyaman University, Medical Faculty, Medical Genetic Department, diyaman, Turkey TUBITAK MRC Genetic Engineering and Biotechnology Institute GEBI), Kocaeli, Turkey Institute for Molecular Medicine and Max-Planck 2169 Research roup on Stem Cell Aging, University of Ulm, Albert-Einstein-Allee 11, lm, Germany Departmentof Biochemistry, Faculty ofVeterinaryMedicine,Mehmet kif Ersoy University, Burdur, Turkey Erciyes University, Medical Faculty, Medical Genetic Department, ayseri, Turkey Bulgarian Academy of Sciences, Institute of Molecular Biology, 21 cad. G. Bonchev str.1113 Sofia, Bulgaria

Comparative Raman study of isostructural YCrO3and YMnO3: Effects of structural distortions and twinning

N. D. Todorov,1,* M. V. Abrashev,1 V. G. Ivanov,1 G. G. Tsutsumanova,1 V. Marinova,2 Y.-Q. Wang,3 and M. N. Iliev3 1Faculty of Physics, University of Sofia, BG-1164 Sofia, Bulgaria 2Institute for Optical Materials and Technologies, Bulgarian Academy of Sciences, BG-1113 Sofia, Bulgaria 3Texas Center for Superconductivity and Department of Physics, University of Houston, Texas 77204-5002, USA (Received 30 March 2011; revised manuscript received 13 May 2011; published 21 June 2011)

New Features in Electroless Deposition of Ternary Coatings on the Base of Ni-P and Co-P

Abstract The new features in the electroless (autocatalytic) deposition, structure and properties of Ni-Cu-P, Ni-Sn-P, Ni-Zn-P, Ni-W-P, Co-W-P, and Co-Re-P as well as the quaternary coatings Ni-Sn-Cu-P, Ni-W-Re-P, and Co-Re-Ni-P established in the Institute of Physical Chemistry of the Bulgarian Academy of Sciences (IPC BAS) are reviewed. The role of disproportionation reactions of Cu(I), Sn(II) and Re(VI) during electroless deposition of Ni-Cu-P, Ni-Sn-P and Co-Re-P is considered. The data about the localization and chemical state of Zn, W and Re are presented. The influence of Cu and Sn added to high P (> 10 wt. %) Ni-P coatings on the thermal stability of their amorphous state is illustrated. A comparison of the corrosion resistance of Ni-Cu-P and Ni-Sn-P with that of Ni-P with the same quantity of phosphorus is given. The application of Ni-Cu-P in a hybrid multilayer with TiN is demonstrated.

Lower Troposphere Observation over Urban Area with Lidar at 1064 nm

An episode of relatively thick (till 3 km) aerosol formation over the urban area of Sofia city was observed by lidar at a wavelength of 1064 nm. The lidar is part of Sofia lidar station at the Institute of Electronics of Bulgarian Academy of Sciences. Analysis of the weather conditions during the measurement period explains the stable persistence of such formation of human-activity aerosol over the town for the days of observation 20, 21, 23, and 24 June, 2011. The estimated top of the Planetary Boundary Layer for the measurement dated 23 June showed unusually high altitude 2200 m above ground. The results are presented in terms of vertical atmospheric backscatter coefficient profiles and color maps of the aerosol stratification evolution.

Investigation of primary to secondary leakage at low power during “Hydro-test” for VVER440/V230 at Kozloduy NPP

This paper presents the thermal–hydraulic investigation “Primary to secondary leakage at low power” for analytical validation of Symptom Based Emergency Operating Procedures (SBEOPs) at low power for VVER440/V230 units 3 and 4 at Kozloduy NPP. The main purpose of this analysis is to provide the response of monitored plant parameters to identify symptoms available to the operators and define timing for reaching the following stages during the development of processes in the reactor system, after primary to secondary leakage: • Reaching the saturated temperature at the outlet of the assembly. • Beginning of reactor core uncovery. • Define the time for reaching maximum level in the damaged SG. • Termination of natural circulation after decreasing of water level in reactor vessel below the hot nozzles. • Defining the time for opening SVs of damaged SG. • Define the CSF status and the time of loss of Critical Safety Functions. The thermal–hydraulic analysis for analytical validation of Symptom Based Emergency Operating Procedures (SBEOPs) at low power of reactor for VVER440/V230 units 3 and 4 at Kozloduy NPP is performed with RELAP5/MOD3.2 computer code. The RELAP5/MOD3.2 model of Kozloduy NPP VVER-1000 for investigation of operational occurrences, abnormal events, and design basis scenarios have been developed and validated in the Institute for Nuclear Research and Nuclear Energy – Bulgarian Academy of Sciences (INRNE–BAS) Sofia, and Kozloduy NPP. The model provides a significant analytical capability for the specialists working in the field of NPP safety.

Galois geometries and applications

From May 25 to 29, 2009, the international conference Galois Geometries andApplications 2009 took place in Ghent, Belgium. The goal was to highlight Galois geom-etries, the study of projective spaces over finite fields, and its many applications in relatedresearch areas, such as coding theory, cryptography, and design theory.This conference was attended by 54 participants, of which 29 were international partici-pants. There were four invited speakers1. Ivan Landjev (Bulgarian Academy of Sciences): Galois geometries and coding theory.2. Keith Martin (Royal Holloway, England): Galois geometry and cryptography.3. Alexander Pott (Otto-von-Guericke-Universitat, Magdeburg, Germany): (Almost) Per-fect nonlinear functions in cryptography and geometry.4. MerceVillanueva(UniversitatAutonomadeBarcelona,Spain):Nonlinearperfectcodesand their impact on designs and geometry.The proceedings of this conference present new research results on Galois geometries andon related areas such as coding theory and cryptography. In total, there are 11 contributedarticles.There are articles specifically dedicated to Galois geometries. Namely, small point setsof PG(

Poxviruses: smallpox vaccine, its complications and chemotherapy

Poxviruses: smallpox vaccine, its complications and chemotherapy Mimi RemichkovaDepartment of Pathogenic Bacteria, The Stephan Angeloff Institute of Microbiology, Bulgarian Academy of Sciences, Sofia, BulgariaAbstract: The threat of bioterrorism in the recent years has once again posed to mankind the unresolved problems of contagious diseases, well forgotten in the past. Smallpox (variola) is among the most dangerous and highly contagious viral infections affecting humans. The last natural case in Somalia marked the end of a successful World Health Organization campaign for smallpox eradication by vaccination on worldwide scale. Smallpox virus still exists today in some laboratories, specially designated for that purpose. The contemporary response in the treatment of the post-vaccine complications, which would occur upon enforcing new programs for mass-scale smallpox immunization, includes application of effective chemotherapeutics and their combinations. The goals are to provide the highest possible level of protection and safety of the population in case of eventual terrorist attack. This review describes the characteristic features of the poxviruses, smallpox vaccination, its adverse reactions, and poxvirus chemotherapy.Keywords: poxvirus, smallpox vaccine, post vaccine complications, inhibitors

Copper impairs biliary epithelial cells and induces lipid peroxidation, protein oxidation and oxidative DNA damage in the isolated perfused rat liver

Event Abstract Back to Event Copper impairs biliary epithelial cells and induces lipid peroxidation, protein oxidation and oxidative DNA damage in the isolated perfused rat liver Albena Alexandrova1*, Lubomir Petrov1, Margarita Kirkova1, Elina Tzvetanova1, Almira Georgieva1, Galina Nenkova1 and Stefani Vircheva1 1 Bulgarian Academy of Sciences, Institute of Physiology, Bulgaria The liver can be damaged by a wide variety of toxicants, including heavy metals. Although copper is an essential micronutrient, it can be harmful in excess. The isolated perfused rat liver model is considered to be a sensitive system for studying chemically-induced hepatotoxicity. In literature, however, there are rather scarce data about copper effects on isolated perfused rat liver. The hepatic injury, caused by copper overload is hypothesized to result from its role in the generation of reactive oxygen species (ROS). Being highly reactive ROS are able to impair all cellular constituents – lipids, proteins and DNA. The aim of the present study was to investigate whether CuSO4 (0.01, 0.03, and 0.1 mM) in perfused rat liver (for 60 min) was associated with lipid peroxidation, protein oxidation, and oxidative DNA damage, as well as with biliary epithelial cell injury. The results regarding liver viability and function (copper decreased the portal flow and bile secretion and led to liver swelling) showed a concentration-response effect. The highest tested concentration of copper caused complete blockage of portal flow and bile production within 30 min of perfusion. In confirmation of copper-induced injury, increased leakage of lactate dehydrogenase, aspartate transaminase, and alanine transaminase (indexes of hepatocellular membrane integrity) into perfusate were registered. Compared to controls, 0.01 and 0.03mM concentrations of copper increased the amount of thiobarbituric acid reacting substances, a marker of lipid peroxidation, tissue protein carbonyl groups, an index of protein oxidation, and 8-oxo-7,8-dihydro-2-deoxyguanosine, a marker of oxidative DNA damage; the biliary levels of gamma-glutamyltransferase, an index of biliary epithelial cell integrity, were also increased. The results suggest that copper toxicity in the isolated perfused rat liver could be a consequence of its ability to impair the integrity of biliary epithelial cells and is associated with the enhanced lipid peroxidation, protein oxidation, and oxidative DNA damage. Keywords: Copper, Bile, Oxidative Stress Conference: 8th Southeast European Congress on Xenobiotic Metabolism and Toxicity - XEMET 2010, Thessaloniki, Greece, 1 Oct - 5 Oct, 2010. Presentation Type: Poster Topic: Xenobiotic toxicity Citation: Alexandrova A, Petrov L, Kirkova M, Tzvetanova E, Georgieva A, Nenkova G and Vircheva S (2010). Copper impairs biliary epithelial cells and induces lipid peroxidation, protein oxidation and oxidative DNA damage in the isolated perfused rat liver. Front. Pharmacol. Conference Abstract: 8th Southeast European Congress on Xenobiotic Metabolism and Toxicity - XEMET 2010. doi: 10.3389/conf.fphar.2010.60.00099 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 28 Oct 2010; Published Online: 04 Nov 2010. * Correspondence: Dr. Albena Alexandrova, Bulgarian Academy of Sciences, Institute of Physiology, Sofia, Bulgaria, a_alexandrova_bas@yahoo.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Albena Alexandrova Lubomir Petrov Margarita Kirkova Elina Tzvetanova Almira Georgieva Galina Nenkova Stefani Vircheva Google Albena Alexandrova Lubomir Petrov Margarita Kirkova Elina Tzvetanova Almira Georgieva Galina Nenkova Stefani Vircheva Google Scholar Albena Alexandrova Lubomir Petrov Margarita Kirkova Elina Tzvetanova Almira Georgieva Galina Nenkova Stefani Vircheva PubMed Albena Alexandrova Lubomir Petrov Margarita Kirkova Elina Tzvetanova Almira Georgieva Galina Nenkova Stefani Vircheva Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Manipulating cytochrome P450 enzymes: new perspectives for cancer treatment

Manipulating cytochrome P450 enzymes: new perspectives for cancer treatment

Preventive effect of polyphenols from geranium sanguineum l on hepatic drug metabolism in influenza infected mice.

Event Abstract Back to Event Preventive effect of polyphenols from geranium sanguineum l on hepatic drug metabolism in influenza infected mice. Lyubka Tantcheva1, Eleonora Encheva2*, Silvyia Abarova2, Julia Serkedjieva3, Iliana Dimova1 and Elitza Pavlova4 1 Institute of Neurobiology, Bulgaria 2 Medical University-Sofia, Bulgaria 3 Bulgarian Academy of Sciences, Institute of Microbiology, Bulgaria 4 St Kliment Ohridsky Sofia University, Bulgaria Introduction: Inhibited first phase of drug metabolism is a main reason for numerous side effects and increased drug toxicity, observed in the course of influenza virus infection (IVI). Medical plant Geranium Sanguineum L. (GSL), spread in the Balkans, demonstrated significant antioxidant and antiviral activity. The aim of the study is to evaluate the preventive effect of polyphenol complex (PPC) from GSL on the oxidative drug metabolism in IVI. Methods: The experimental model of IVI (A/Aichi/2/68/(H3N2)(4.5 lg LD50) is developed in male albino ICR mice. PPC is applied nasally (10 mg/kg). In liver 9 000 g supernatant thiobarbituric acid reactive substances (TBARS) and antioxidant total activity (ATA) as well as monooxygenase N-demethylase activity (ethylmorphyne, amidopyrine and analgin) and hydroxylase activity (aniline and p-nitrophenol), NADPH- cytochrtome P-450 reductase and cytochrome P-450 content are determined. Student-Fisher t-test and correlation coefficients are used for statistics. Results: High correlation between increased TBARS and decreased monooxygenase activity (p< 0.001) is found in infected animals. It suggests that activation of free radicals can be one of the main reasons for unspecific monooxygenase inhibition, because all components of cytochrome P-450 system are inhibited (mostly the on the 6th and 9th days). PPC pretreatment demonstrates significant preventive effect against increased levels of TBRS and decreased ATA. Drug metabolism in IVI mice is restored by PPC near to healthy controls. Conclusion: TBARS probably play important role not only in the pathogenesis of IVI, but also in modulation of hepatic monooxygenase activity. All inhibited P-450 monooxygenase activities are significantly restored by PPC pretreatment. The complex mechanism of PPC-protective effect obviously combines several biological activities- antioxidant activity, selective antiviral and protein-bounding effect. In contrast to infected animals, PPC has medium pro-oxidant and weak inhibiting effect on monooxygenases in healthy animals, probably related to its protein–binding effect on membrane proteins and enzymes. Keywords: influenza infection, drug metabolism, cyt P-450 monooxygenases, Polyphenols, Geranium Sanguineum L. Conference: 8th Southeast European Congress on Xenobiotic Metabolism and Toxicity - XEMET 2010, Thessaloniki, Greece, 1 Oct - 5 Oct, 2010. Presentation Type: Poster Topic: Xenobiotic metabolism Citation: Tantcheva L, Encheva E, Abarova S, Serkedjieva J, Dimova I and Pavlova E (2010). Preventive effect of polyphenols from geranium sanguineum l on hepatic drug metabolism in influenza infected mice.. Front. Pharmacol. Conference Abstract: 8th Southeast European Congress on Xenobiotic Metabolism and Toxicity - XEMET 2010. doi: 10.3389/conf.fphar.2010.60.00203 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 28 Oct 2010; Published Online: 04 Nov 2010. * Correspondence: Dr. Eleonora Encheva, Medical University-Sofia, Sofia, Bulgaria, eleonora.encheva@medfac.acad.bg Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Lyubka Tantcheva Eleonora Encheva Silvyia Abarova Julia Serkedjieva Iliana Dimova Elitza Pavlova Google Lyubka Tantcheva Eleonora Encheva Silvyia Abarova Julia Serkedjieva Iliana Dimova Elitza Pavlova Google Scholar Lyubka Tantcheva Eleonora Encheva Silvyia Abarova Julia Serkedjieva Iliana Dimova Elitza Pavlova PubMed Lyubka Tantcheva Eleonora Encheva Silvyia Abarova Julia Serkedjieva Iliana Dimova Elitza Pavlova Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Funeral golden mask and hand with a ring. The necropolis of Trebeniste

This study reviews the historical background of the Necropolis of Trebeniste while also highlighting some of the main hypotheses that help date this site and explain its significance. Furthermore, it provides a description of the tombs and focuses on two of the golden objects excavated from the graves – a funeral golden mask and a hand with a ring. It lays out the results of an analysis of the crafting techniques used – one that was conducted at a laboratory of the National Archaeological Institute with Museum under the Bulgarian Academy of Sciences in Sofia, Bulgaria. This analysis aims to contribute to the further investigation and argumentation pertaining to the dating of these findings. It also hopes to suggest potential new areas of research.

Visco-elastic mechanical properties of human abdominal fascia

Visco-elastic mechanical properties of human abdominal fascia O 79 80 81 82 83 O Miglena Kirilova *, Stoyan Stoytchev , Dessislava Pashkouleva , Vesselina Tsenova , Radka Hristoskova b R 84 85 86 87 88 89 90 P a Institute of Mechanics, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 4, Sofia 1113, Bulgaria b Department of Clinical Pathology, Tsaritsa Joanna University Hospital, 1527 Sofia, Bulgaria

Loss of ‘Core cooling’ at low power and cold condition of VVER-1000/V320

This paper presents the results of thermal–hydraulic calculation of accident scenarios that involve the loss of critical safety function (CSF) “Core cooling” for VVER-1000/V320 units at Kozloduy nuclear power plant done during the development of symptom based emergency operating procedures (SB EOPs) for this plant at low power and cold condition. The main purpose of this analysis is to provide the response of monitored plant parameters to identify symptoms available to the operators and define timing for reaching the following stages during the development of processes in the reactor system: ○ Reaching the saturated temperature at the outlet of the assembly; ○ Beginning of reactor core uncovery; ○ Heating up of fuel; ○ Defining the transition time between EOPs and SAMG at temperature of 923 K; ○ Restoring of water level in the reactor; ○ Defining the CSF “Core cooling” status and the time of its loss. The results of the thermal–hydraulic analyses have been used to assist KzNPP specialists in analytical validation of EOPs at low power and cold condition. The principal acceptance criteria for EOPs are averting the onset of core damage. The RELAP5/MOD3.2 computer code has been used in performing the analyses in a VVER-1000 nuclear power plant (NPP) model. A model of VVER-1000 based on Unit 6 of KzNPP has been developed for the systems thermal–hydraulics code RELAP5/MOD3.2 at the Institute for Nuclear Research and Nuclear Energy – Bulgarian Academy of Sciences (INRNE – BAS), Sofia. The low power and cold condition and the modifications after the modernization program are taken into account.

Updated archeomagnetic data set of the past 8 millennia from the Sofia laboratory, Bulgaria

This data brief reports the latest updates of archeomagnetic data obtained at the Sofia palaeomagnetic laboratory of the Geophysical Institute, Bulgarian Academy of Sciences. The current data set consists of measurements from 284 Bulgarian archeological sites covering the past 8000 years. There are also 54 sites from other European regions, namely, Serbia, Kossovo, Greece, Spain, Switzerland, Finland, and Russian Karelia, as well as five sites from Morocco in North Africa. The update of the archeomagnetic results consisted of a thorough revision of all geomagnetic field measurements as well as dating these measurements that were published in the original papers or in previous compilations. The updated results can be found in GEOMAGIA (http://geomagia.ucsd.edu) or as an Excel spreadsheet at the EarthRef.org Digital Archive (http://earthref.org/cgi‐bin/erda.cgi?n = 946).

The Genus Verrucaria (Verrucariaceae) in Bulgarian Collections

ABSTRACTIn the collections of the Institute of Botany (Bulgarian Academy of Sciences), the Faculty of Biology (Sofia University “St. Kliment Ohridski”) and the National Museum of Natural History (Bulgarian Academy of Sciences) are housed many lichen specimens, collected in Bulgaria by different scientists. Among them 10 species of Verrucaria are represented. Foreign specimens, kept in SO and SOMF have been studied for comparison with the Bulgarian ones. Recent data on the distribution of some Verrucaria species is given also.

Concept for sustainable development of tourist destination (on the example of Varna municipality)

Title of the dissertationConcept for sustainable development of tourist destination (on the example of Varna municipality)SupervisorProf. Svetla Rakadjiiska, University of Economics - Varna, BulgariaInstitution awarding the Ph. D. DegreeInstitute of Economics, Bulgarian Academy of Sciences, SofiaDate of defence17th April 2008Goal and objectives of the dissertationGoalThe main goal is to develop a concept for sustainable development of tourist destinations, and the specific mechanism for its implementation. The author's thesis is that achieving the necessary sustainable development of tourist destination requires clear concepts and specific mechanisms. These are elaborated on the basis of analysed sustainable development of the destination, taking into account specific environment and pre-conditions, in order to achieve a balance between the destination development and preservation of its natural and social environment.Objectives1. Presenting a concept for solving negative impacts of tourism development at the tourist destination.2. Defining a solution for preventing and eliminating the negative consequences of tourism development in the destination, while keeping or increasing its competitiveness and attractiveness.3. Defining a specific methodology and mechanism for the implementation of the solution for a balance between tourism development and long term development of the destination.Methodology1. Theoretical and comparative analysis.2. Methods of deduction and induction.3. Survey of 50 respondents, including representatives of tourist organisations, the local government, public institutions and NGOs. The survey was conducted in Varna municipality.4. Analysis of sustainable development of the tourist destination implementing a specially elaborated methodology.Results1. Elaborated concept for development of tourist destinations based on the theory of sustainable development.2. Elaborated specific mechanism for sustainable development of the tourist destination identified as a key determinant for sustainable development of the tourist destination.3. Created appropriate methodology for the analysis and assessment of sustainable development of the tourist destination.4. The methodology for analysis and assessment of sustainable development of the tourist destination as implemented and tested for Varna Municipality.5. The directions for sustainable development of Varna tourist destination are determined.Theoretical conclusionsThe idea of sustainable development is fundamental for tourism transformation, because the negative impacts on the natural and social environment are minimised fostering positive short and long-term economical and social benefits. Sustainable development of tourism can be better achieved when the specific characteristics and problems are raised and addressed, meaning they should be considered at the local level, namely the tourist destination.To achieve balance between the development of the tourist destination and preservation of the environment, key resources and values, that are critical for having a sustainable destination, should be identified and protected. This includes the elaboration of specific mechanism for sustainable development of the tourist destination, for example the preservation of the irreversible natural and social capital.Practical application of the dissertationThe concept of sustainable development of the tourist destination can be used for:- solving the problem of de-coupling the tourism development from its destructive exploitation of natural and social capital without decreasing the well-being of local population;- creating a strategy for the development of the tourist destination based on the principles of sustainable development.Content of the dissertationAbstract of chapter oneIn the first chapter, the concept of sustainable development of tourist destinations is elaborated. …

Balkan Nephropathy: Evolution of Our Knowledge

Balkan endemic nephropathy (BEN), originally described in the late 1950s as a chronic tubulointerstitial kidney disease, is identified by its unique epidemiological features. The most remarkable characteristic of BEN is the focal topographical nature that characterizes its occurrence at the global, national, and even household level. BEN affects only certain endemic rural foci along tributaries of the Danube River in the Balkan countries of Bosnia, Bulgaria, Croatia, Romania, and Serbia. The spatial distribution has remained astonishingly unchanged with time because the disease affects the same endemic clusters as 50 years ago. The natural course of the disease is characterized by universal development of end-stage renal disease and the frequent development of upper urinary tract tumors, posing a substantial disease burden to the afflicted areas. The greatest challenge in the study of BEN has been the elucidation of its cause. The unique features of the disease, in particular its endemic nature and the long incubation period required for the disease to develop, have led to the proposal that BEN represents a unique environmental disease. The quest for the responsible environmental factor has been long and diverse, and although no definitive answer has been provided to date, converging lines of evidence support the theory that long-term consumption of food contaminated with aristolochic acid underlies the pathogenesis of BEN. The present review describes the evolution of our knowledge of BEN in relation to the development of the main theories for its pathogenesis.

Starting a programme for research and monitoring of sediment transfer processes in the periglacial zone of Bulgaria (Bulgarian Periglacial Programme)

The Bulgarian Periglacial Programme is organized by the Institute of Geography of Bulgarian Academy of Sciences. It aims to investigate and observe contemporary geomorphic processes that occur in the Bulgarian periglacial zone located in the alpine and subalpine parts of the Rila and Pirin Mountains at altitudes of 2200–2925 m a.s.l.). The research will be used to create a set of landscape models, which to be used for assessment environmental reactions to global change and for environmental hazards risk assessment. Realization of the programme is of considerable importance for the Institute and for Bulgarian science as a whole and this type of research is currently lacking in the Bulgarian periglacial environment. The programme should be performed in close collaboration with European and global scientific community, with application of up-to-date standardized methods which to allow comparison with results from studies conducted elsewhere in the world. In essence, the Bulgarian Periglacial Programme is not a project – it is much more a strategic line, which should generate series of project proposals that will ensure the fulfilment of all the tasks planned. Hence, the main goal of the programme is to ensure an international partnership on wide basis.

Theta responses during passive listening depend on cognitive abilities in children

Event Abstract Back to Event Theta responses during passive listening depend on cognitive abilities in children Vasil Kolev1*, P. Nanova1 and Juliana Yordanova1 1 Bulgarian Academy of Sciences, Bulgaria Cognitive development in children is accompanied by changes in frequency content of the spontaneous and event-related EEG activity. Event-related theta (4-7 Hz) and alpha (8-13 Hz) oscillations have been implicated with cognitive information processing in both children and adults. Typically, the functional relevance of EEG frequency responses is evaluated in task processing conditions. This type of assessment does not permit to reliably distinguish between task-related functional involvement and neurophysiological maturity of different EEG rhythms. The present study addressed this issue by comparing event-related oscillatory responses to passive (no task) stimuli of children at 6-8 years of age, who varied with respect to their cognitive performance in a working memory task (see accompanying abstract). According to verbal and reaction time criteria, twenty six normal healthy children were divided into two groups of good and bad performers (each comprising 13 subjects, mean group age 85 months, p>0.8). Auditory event-related potentials (ERPs) in response to 50 identical tones presented in a passive listening condition were recorded. Time-domain ERP analysis demonstrated that the latencies of N1 and P2 components were significantly shorter in good relative to bad performers. Also, in contrast to bad performers, a prominent positive wave P330 characterized in ERPs of good performers. Time-frequency ERP analysis demonstrated that theta but not delta (0.5-4 Hz) and alpha frequency ERP components differentiated passive stimulus processing in the two groups. As shown on the Figure, strongly enhanced theta oscillations within 250-500 ms after stimulus occurred synchronously at the three electrodes only in the group of good performers. Also, corresponding to latency shifts, oscillatory theta responses were phase delayed in bad performers, mostly at the central and parietal sites. These distinct patterns of oscillatory theta responses observed between the two groups during passive processing conditions imply that differences in memory performance are accompanied by specific organization of the underlying neural substrate. * Supported by the National Science Fund at the Ministry of Science and Education, Sofia, Bulgaria (L-1501/2005). pic1 pic tn_pic1 Conference: 10th International Conference on Cognitive Neuroscience, Bodrum, Turkey, 1 Sep - 5 Sep, 2008. Presentation Type: Poster Presentation Topic: Brain Electrical Oscillations in Cognition Citation: Kolev V, Nanova P and Yordanova J (2008). Theta responses during passive listening depend on cognitive abilities in children. Conference Abstract: 10th International Conference on Cognitive Neuroscience. doi: 10.3389/conf.neuro.09.2009.01.129 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 05 Dec 2008; Published Online: 05 Dec 2008. * Correspondence: Vasil Kolev, Bulgarian Academy of Sciences, Sofia, Bulgaria, vasil_kolev@yahoo.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Vasil Kolev P. Nanova Juliana Yordanova Google Vasil Kolev P. Nanova Juliana Yordanova Google Scholar Vasil Kolev P. Nanova Juliana Yordanova PubMed Vasil Kolev P. Nanova Juliana Yordanova Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.