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214 results on '"Georgieva, B"'

2. Role of Bacterial and Viral Infections and Co-Infections in Miscarriages

Author

Mesechkova K., Kavrakova A., Todorova E., Georgieva B., Sigridov I., Mitev V., and Todorova A.

Subjects
endometrium, inflammation, hhvs, infertility, menstrual tissue, Medicine
Abstract

To investigate the potential role of the following bacterial/viral panel (Chlamydia trachomatis, Ureaplasma urealyticum/parvum, Mycomplasma hominis/genitalium, Gardnerella vaginalis, HSV1/2, EBV, CMV, VZV, HHV6, HHV7, HHV8) as causative factors for miscarriages in women by testing endometrial biopsies. Anaerobic and aerobic microorganisms causing dysbiosis and endometrial bacterial colonization by unbalanced growth were additionally tested.

Published
2023
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3. Non-Invasive Diagnostics of Reproductive Failure with Infectious Etiology on Menstrual Tissue

Author

Mesechkova K., Kavrakova A., Georgieva B., Sigridov I., Mitev V., and Todorova A.

Subjects
endometrium, inflammation, hhvs, infertility, menstrual tissue, Medicine
Abstract

We investigated the role of bacterial (Chlamydia trachomatis, Ureaplasma urealyticum/ parvum, Mycoplasma hominis/genitalium, Gardnerella vaginalis) and viral (HSV1/2, EBV, CMV, VZV, HHV6/HHV7, HHV8) pathogens, as a potential cause of reproductive failure in women by testing menstrual tissue samples.

Published
2023
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7. Molecular-Genetic Diagnostics of Angelman Syndrome – The Bulgarian Experience

Author

Georgieva B., Atemin S., Todorova A., Todorov T., Miteva A., Avdjieva-Tzavella D., and Mitev V.

Subjects
angelman syndrome, ube3a, imprinting center, cpg methylation, 15q11.2-q13, paternal upd, Medicine
Abstract

Objective: The aim of the study was to determine the molecular mechanisms of mutagenesis in Bulgarian patients with Angelman syndrome (AS). AS is a severe neurodevelopmental disorder caused by loss of expression in brain of the maternally inherited UBE3A gene as a result of various 15q11.2-q13 alterations.

Published
2020
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14. P013 Tuberculosis or cystic fibrosis

Author

Petrova, G., primary, Hinkov, G., additional, Baycheva, M., additional, Georgieva, B., additional, Papochieva, V., additional, Yaneva, N., additional, Zlatev, A., additional, and Savov, A., additional

Published
2023
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21. Molecular Diagnostics of Duchenne/Becker Muscular Dystrophy Patients by Multiplex Ligation-Dependent Probe Amplification Analysis and Direct Sequencing

Author

Todorova A, Guergueltcheva V, Genova J, Mihaylova V, Todorov T, Tchamova T, Georgieva B, Kremensky I, Tournev I, and Mitev V

Subjects
duchenne/becker muscular dystrophy (dmb/bmd), dmd gene, dystrophin, deletions, duplications, point mutations, multiplex ligation-dependent probe amplification (mlpa) analysis, Genetics, QH426-470
Published
2009
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22. Environmental changes in southeastern Europe over the last 450 ka: Magnetic and pedologic study of a loess-paleosol profile from Kaolinovo (Bulgaria)

Author

Jordanova, D., Simon, Quentin, Balescu, S., Jordanova, N., Ishlyamski, D., Georgieva, B., Bourles, D.L., Duvivier, A., Cornu, Sophie, Bulgarian Academy of Sciences (BAS), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), and Université de Lille

Subjects
Quaternary, Archeology, Global and Planetary Change, Environmental magnetism, Paleoclimate, [SDU]Sciences of the Universe [physics], Pedology, Pedogenic iron oxides, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Geology, Ecology, Evolution, Behavior and Systematics
Abstract

International audience; Magnetic properties are sensitive paleoenvironmental proxies frequently used in studies of loess paleosol profiles. Understanding precisely the magnetic recording of soil responses to environmental and climatic changes needs combining pedologic data and geophysical proxies. Here we present a new high-resolution study of a 450 ka old loess-paleosol profile from low Danube loess area at Kaolinovo (NE Bulgaria). The profile consists of Holocene soil S0 on top, three paleosol units (S1, S2, S3-S4) and the intercalated loess horizons L1 to L4. Mineral magnetic and rock magnetic data together with pedological parameters (particle size distribution, total, crystalline and amorphous iron, soil organic carbon, total nitrogen, cation exchange capacity, carbonate content) show systematic variations in response to environmental changes. Principal component analyses carried out separately on magnetic mineralogy, rock magnetic and pedological variables reveal the complex response of loess - paleosol sediments to changes in source material and climate. The observed sharp shift in coercivity of mineral magnetic carriers at depth of the third loess L3 marks the change from low-coercivity mineral assemblages in older units to higher coercivity in the last three loess paleosol couplets (L1-S0, L2-S1, L3 - S2). This boundary is related to both dust source change and increased climate aridity. The observed spikes in concentration-dependent magnetic parameters in the lowermost part of the profile and particular magnetic and pedologic signature of the oldest deposits (S3-S4 pedocomplex) suggest that it may result from tephra additions in the studied loess-paleosol sequence, tentatively correlated to cryptotephra layers in other terrestrial archives in the region like Tenaghi Philippon and lake Ohrid sedimentary sequences. This work demonstrated that using PCA tool for studying the significance and objective inter-relationships of multiple mineralogical, mineral magnetic and pedological characteristics along depth of loess - paleosol profiles is an exemplary approach for revealing the underlying sedimentary and environmental processes.

Published
2022
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31. Structure and Phase Composition Study of Heavy Doped with Carbon Thin Films of TiO2 : C Deposited by RF Magnetron Sputtering.

Author

Milenov, T., Terziyska, P., Avdeev, G., Karashanova, D., Georgieva, B., Avramova, I., Genkov, K., and Valcheva, E.

Abstract

The aim of the present research is to study some aspects of the carbon doping of TiO2 thin films and the influence of low temperature thermal annealing on the phase precipitation in thin films. Тhin films of heavily doped with carbon TiO2 (up to 3 at % C) were deposited on (15 × 25 × 1 mm) glass substrates by r.f. magnetron co-sputtering of TiO2 target and carbon plates on its erosion zone in Ar + air (residual pressure of 0.5 and 0.6 Pa, respectively) atmosphere. Two different process's parameters were varied in different experiments in order to change the carbon content: the total area of the carbon plates which was 30, 84, 132, 400 and 830 mm2) and the radial distance between the center of the circle of the erosion zone with maximum rate of sputtering which was 2 and 4 cm. The as-deposited and annealed (air, 400°C, 1h) thin films with thickness of 110–150 nm were studied by ellipsometry, grazing incidence X-ray diffractometry (GIXRD), X-ray photoelectron spectroscopy, Raman spectroscopy, transmission and scanning electron microscopies. The GIXRD patterns reveal a mix of amorphous and nanocrystalline anatase and rutile TiO2 phases for all thin films. The Raman study confirms this conclusion but the TEM and GIXRD studies show presence of non-stoichiometric nanocrystalline phase based on Ti3C20O14 together with the other phases of TiO2-anatase, rutile and brookite. Similar charcterizations were carried out after annealing at 400°C in air for 60 min and the most prominent effects of thermal treatment are discussed. [ABSTRACT FROM AUTHOR]

Published
2022
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33. Structure and phase composition study of thin TiO2:C films deposited by r.f. magnetron sputtering

Author

Valcheva, E., Kolev, S., Ivanov, K., Dimov, D., Georgieva, B., Genkov, K., Terziyska, P., Angelov, O., Karaivanova, D., Milenov, T., Avdeev, Georgi, and Karashanova, D.

Subjects
History, Computer Science Applications, Education
Abstract

Thin films of TiO2 doped with carbon were deposited on 15×25×1 mm3 glass substrates by r.f. magnetron co-sputtering of TiO2 target and carbon plates on their erosion zone in Ar + air atmosphere (0.5 Pa and 0.6 Pa, respectively). Two different process parameters were varied in different experiments: the total area of the carbon plates (84 mm2, 560 mm2, 830 mm2 or 1480 mm2) and the radial distance from the center of the circle of the erosion zone with maximum rate of sputtering (2 cm or 4 cm). The as-deposited and annealed (air, 400 °C, 1 h) thin films with thicknesses of 40 - 60 nm were studied by ellipsometry, grazing incidence X-ray diffractometry (GIXRD), Raman spectroscopy, transmission (TEM) and scanning electron microscopies (SEM). The ellipsometric studies revealed the band gap, as well as the tail states and optical constants of the thin films obtained. The GIXRD patterns revealed a mix of amorphous and nanocrystalline anatase and rutile TiO2 phases in all thin films. The Raman study confirmed this conclusion, but the TEM study showed the presence of some nanocrystalline C20O14Ti3, together with the other TiO2 phases - brookite and nonstoichiometric TiOx phases (anatase and rutile). The effects of annealing at 400 °C in air for 60 min are also discussed.

Published
2022
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34. Nd:YAG laser ablation of micro-crystalline graphite in a water suspension

Author

Milenov, T, primary, Dimov, D, additional, Nikolov, A, additional, Stankova, N, additional, Avramova, I, additional, Avdeev, G, additional, Russev, S, additional, Karashanova, D, additional, Georgieva, B, additional, Kostadinov, I, additional, Karaivanova, D, additional, Kolev, S, additional, and Valcheva, E, additional

Published
2021
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35. Modification of thin carbon films by UVc light

Author

Milenov, T, primary, Dikovska, A, additional, Avramova, I, additional, Karaivanova, D, additional, Avdeev, G, additional, Terziyska, P, additional, Dimov, D, additional, Karashanova, D, additional, Georgieva, B, additional, Kolev, S, additional, and Valcheva, E, additional

Published
2021
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42. Structural study of thick hexaferrite films

Author

Koutzarova, T, primary, Georgieva, B, additional, Kolev, S, additional, Ghelev, Ch, additional, Krezhov, K, additional, Kovacheva, D, additional, Vertruyen, B, additional, Closset, R, additional, Tran, L-M, additional, and Zaleski, A, additional

Published
2020
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43. Initial conditions for preparation of thin AlN films by atomic layer deposition

Author

Beshkova, M., Blagoev, B. S., Mehandzhiev, V, Yakimova, Rositsa, Georgieva, B., Avramova, I, Terziyska, P., Kovacheva, D., Strijkova, V, Beshkova, M., Blagoev, B. S., Mehandzhiev, V, Yakimova, Rositsa, Georgieva, B., Avramova, I, Terziyska, P., Kovacheva, D., and Strijkova, V

Abstract

Thin AlN films were grown on Si substrates in a Beneq TFS-200 ALD reactor. The atomic layer deposition (ALD) process consisted of two half cycles - aluminum adsorption and nitridization separated by a purging step. TMA (trimethylaluminum) and NH3 were used as precursors, and nitrogen (N-2), as a carrier gas. The pulse duration, purging time, deposition temperature and other deposition conditions were varied to obtain AlN films with desired properties. The X-ray diffraction (XRD) data showed that the AlN films had an amorphous character. The films chemical composition and bonding states were investigated by X-ray photoelectron spectroscopy. The high resolution Al 2p and N 1s spectra confirmed the presence of AlN with peaks located at 74.1 eV and 397.7 eV, respectively, for all layers., Funding Agencies|Bulgarian National Science FundNational Science Fund of Bulgaria [DN 18/6]

Published
2020
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