Georgi B. Hadjichristov, V.K. Gueorguiev, T. Ivanov, Yordan G. Marinov, Victor G. Ivanov, E. Faulques,
The electrical conductivity and field-effect transconductance of polymethylmethacrylate (PMMA) subjected to implantation with 50 keV silicon ions at doses in the range from 1014 to 1017 ions/cm2 were examined. The electrical response of Si+-implanted PMMA was studied by direct current (DC) and alternating current (AC) measurements and was related to the structure formed in the host polymer. In addition to the sizable enhancement of the conductivity with the implantation dose, the field-effect transconductance ...
Tópico(s): Ion-surface interactions and analysis
2008 - Elsevier BV | Organic Electronics
Manol Ognyanov, Yordan Georgiev, Nadezhda Petkova, Ivan Ivanov, Ivelina Vasileva, Maria Kratchanova,
In the current study, an acidic polysaccharide from the in vitro suspension culture of Fumaria officinalis L. was obtained by extraction with 0.8% (w/v) aqueous ammonium oxalate. The polysaccharide fraction mainly consisted of galacturonic acid (41.0%), followed by galactose (7.3%) and arabinose (5.6%). This suggests the presence of arabinogalactan side chains in the rhamnogalacturonan-I segment of the studied pectin, which was mainly built up by homogalacturonan segments. The pectin was evaluated as ...
Tópico(s): Proteins in Food Systems
2018 - Hindawi Publishing Corporation | International Journal of Polymer Science
Roumyana Mironova, Toshimitsu Niwa, Yordan Handzhiyski, Angelina Sredovska, Iván Ivanov,
Summary We have recently shown that the process of non‐enzymatic glycosylation (glycation) takes place in Escherichia coli under physiological conditions and affects both recombinant and endogenous bacterial proteins. In this study, we further demonstrate that E. coli chromosomal DNA is also subjected to glycation under physiological growth conditions. The E. coli DNA accumulates early glycation (Amadori) products as proven by the nitroblue tetrazolium (NBT) reduction assay. It showed also immunoreactivity ...
Tópico(s): GABA and Rice Research
2005 - Wiley | Molecular Microbiology
Georgi B. Hadjichristov, V.K. Gueorguiev, T. Ivanov, Yordan G. Marinov, Victor G. Ivanov, E. Faulques,
The electrical properties of polymethylmethacrylate (PMMA) after implantation with silicon ions accelerated to an energy of 50 keV are studied under DC electric bias field. The electrical response of the formed material is examined as a function of Si+ fluence in the range 1014 − 1017 cm−2. The carbonaceous subsurface region of the Si+-implanted PMMA displays a significant DC conductivity and a sizable field effect that can be used for electronic applications.
Tópico(s): Ion-surface interactions and analysis
2010 - IOP Publishing | Journal of Physics Conference Series
... Tcl/Tk and Its ApplicationsVeronika Ivanova, Ani Boneva, Yordan Doshev, Stoyan Ivanov and Plamen Vasilev1 Nov 2019 Advances in GeosciencesMetrics ...
Tópico(s): Geomagnetism and Paleomagnetism Studies
2011 - Copernicus Publications | Advances in geosciences
Kiril Kolikov, Dragia Ivanov, Georgi Krastev, Yordan Epitropov, Stefan Bozhkov,
In the paper we consider the problem of the electrostatic interaction between two charged conducting spheres with arbitrary electrical charges and radiuses. Using the image charges method we determine exact analytical formulas for the force F and for the potential energy W of the interaction between these two spheres as well as for the potential V of the electromagnetic field in an arbitrary point created by them. Our formulas lead to Coulomb’s law for point charges. We theoretically prove the experimentally ...
Tópico(s): Advanced Mathematical Theories and Applications
2011 - Elsevier BV | Journal of Electrostatics
Angelina Bozhinov, Yordan Handzhiyski, Krasimir Genov, Vera Daskalovska, Toshimitsu Niwa, Iván Ivanov, Roumyana Mironova,
Human IFN-β proved to be efficient for the treatment of relapsing-remitting multiple sclerosis. There are 2 forms of recombinant human IFN-β on the market, IFN-β1a (Avonex [Biogen Idec Inc, Weston, Mass] and Rebif [Merck Serono S.A., Geneva, Switzerland]) and IFN-β1b (Betaferon and Betaseron [Bayer HealthCare Pharmaceuticals Inc, Berlin, Germany]). IFN-β1a is produced in Chinese hamster ovary cells, whereas IFN-β1b is derived from Escherichia coli. The latter is a nonglycosylated form with a C17S substitution. ...
Tópico(s): Immune Response and Inflammation
2011 - Elsevier BV | Journal of Allergy and Clinical Immunology
Valeri Velev, Maria Pavlova, Ekaterina Alexandrova, Мetodi Popov, Ivan Lutakov, Tatiana Tcherveniakova, Andreana Angelova, Eli Hristozova, Yordan Kalchev, Ivan Ivanov,
One of the most pressing public health problems is the misuse of antibiotics, especially in industrialized countries. In addition to antibiotic resistance, a disease associated with this abuse is Clostridioides difficile infection (CDI). It is also a serious problem in long-term hospital treatment, as it often causes intra-hospital infections. The coronavirus disease 2019 (COVID-19) pandemic has also led to widespread misuse of antibiotics and prolonged hospitalizations. The aim of our study was to ...
Tópico(s): Pediatric Pain Management Techniques
2023 - Taylor & Francis | Biotechnology & Biotechnological Equipment
Ivan Ivanov, Yordan Kumchev, Vincent J. Hooper,
Stroke is a major public health issue with significant economic consequences. This study aims to enhance stroke prediction by addressing imbalanced datasets and algorithmic bias. Our research focuses on accurately and precisely detecting stroke possibility to aid prevention. We tackle the overlooked aspect of imbalanced datasets in the healthcare literature. Our study focuses on predicting stroke in a general context rather than specific subtypes. This clarification will not only ensure a clear ...
Tópico(s): Cerebrovascular and Carotid Artery Diseases
2023 - Multidisciplinary Digital Publishing Institute | Algorithms
Georgi B. Hadjichristov, T. Ivanov, Yordan G. Marinov, Hari Krishna Koduru, N. Scaramuzza,
Ion‐conductive solid polymer electrolytes composed from blends of poly(ethylene oxide) (PEO) and poly(vinylpyrrolidone) (PVP), as complexed with the ionic compound sodium periodate (NaIO 4 ), are inspected for the presence of electric charge trapping (CT) and ionic space charge polarization (SCP) under static electric field. Thin films (110 μm‐thick) of these materials are produced at a ratio of the polymers PEO:PVP = 70:30 wt%, the concentration of NaIO 4 is 5, 7.5, or 10 wt%. The electrical current at room ...
Tópico(s): Advancements in Battery Materials
2019 - Wiley | physica status solidi (a)
Yordan M. Georgiev, G. Mladenov, Deyan Ivanov,
The spatial distributions of absorbed electron energy density in PMMA on structures incorporating YBa2Cu3O7 high-Tc superconducting thin films deposited on different substrates were determined using a Monte Carlo simulation (MCS), which takes into account the exact boundary conditions on interfaces between different layers of the target. The ability of our Monte Carlo program to accurately simulate the radial exposure distributions was demonstrated. The effects of substrate material (SrTiO3 and MgO), ...
Tópico(s): Semiconductor materials and devices
1994 - Elsevier BV | Thin Solid Films
Yordan Stremski, Stela Statkova‐Abeghe, Plamen Angelov, Iliyan Ivanov,
Camalexin is synthesized on a gram scale by coupling of thiazole and indole in an amidoalkylation–oxidation sequence. Several high‐yielding implementations of this two‐step approach are demonstrated with variation of either the intermediate acyliminium reagent or the oxidation conditions. Benzo‐analogues and aza‐analogues of the natural product are also obtained by this method. As a side result, a new formylation of indole is demonstrated.
Tópico(s): Alkaloids: synthesis and pharmacology
2018 - Wiley | Journal of Heterocyclic Chemistry
Yordan Stremski, Desislava Kirkova, Stela Statkova‐Abeghe, Plamen Angelov, Iliyan Ivanov, D Georgiev,
N-acyliminium reagents formed in situ from benzothiazole and alkyl chloroformates react with hydroxyarenes in a Friedel-Crafts manner, providing access to 2-(hydroxyaryl)-benzothiazolines with antibacterial properties.
Tópico(s): Phenothiazines and Benzothiazines Synthesis and Activities
2020 - Taylor & Francis | Synthetic Communications
Stefana Sabtcheva, Ivan Ivanov, Bozhana Todorova, Yordan Simeonov, Elina Dobreva, Krasimira Ivanova, Tzvetan Velinov, Todor Kantardjiev,
We report the identification of OXA-48-producing Klebsiella pneumoniae, causing peritonitis in a cancer patient admitted to the Oncology Hospital in Sofia. The isolate had reduced susceptibility to carbapenems but remained susceptible to extended-spectrum cephalosporins. PCR and sequencing confirmed the presence of blaOXA-48 gene flanked by two intact copies of IS1999 on truncated ΔTn1999.1. This transposon was located on unusual non-typeable 29-kb plasmid that could be transferred only by transformation. ...
Tópico(s): Infections and bacterial resistance
2015 - Taylor & Francis | Journal of Chemotherapy
Yordan Ivanov, Кircho Patrikov,
Introduction : Limb salvage surgery is currently the most frequently used treatment option in Bulgaria for individuals with musculoskeletal malignancies. Clinical data about complications from these procedures is limited in the country, with only a few studies currently available. Aim : The aim of our study is to analyze complication rates and patterns in Bulgarian patients treated with limb salvage surgery for musculoskeletal malignancies. Materials and methods : Our series consist of a retrospective ...
Tópico(s): Beetle Biology and Toxicology Studies
2024 - De Gruyter Open | Folia Medica
Yordan Ivanov, Tsvetan Tsenkov,
Introduction : The functional outcome in patients after limb salvage surgery, and in particular reconstructions with modular tumor endoprostheses, has been the subject of many international series, but only a few publications mention the functionality in a Bulgarian patient group. Aim : The aim of the present study was to analyze the functional outcome in a Bulgarian group of patients with malignant bone tumors that underwent resection and reconstruction with modular tumor endoprostheses. Materials ...
Tópico(s): Bone Tumor Diagnosis and Treatments
2023 - De Gruyter Open | Folia Medica
Nikolai Dishovski, Filis Mitkova, M. K. Kandeva, Yordan Angelov, Ivan M. Uzunov, Milcho C. Ivanov, D. Klissurski,
Slips and falls on icy surfaces can cause serious injuries of people. The primary risk factor for slipping incidents is undoubtedly the decreased friction coefficient between the shoe sole and the ice or snow surface. Nowadays environmental protection has been gaining significance and becoming highly important for the various innovation strategies. In rubber industry the concept of environmental protection is more often associated with the maximum use of elastomers and ingredients from renewable ...
Tópico(s): Winter Sports Injuries and Performance
2018 - Scientific Research Publishing | Materials Sciences and Applications
In the rapidly changing global economy, offshoring and outsourcing have become popular businessstrategies for reducing the costs of companies. A high number of regions and countries have prоfiled andbecome popular offshoring and outsourcing destinations over the past 25 years – Central and South America;Central and Eastern Europe; Southeast Asia, China and India etc. Although, countries like China, India andIreland are traditionally perceived as main countries which receive offshoring and outsourcing ...
Tópico(s): Economic Systems and Logistics Management
2016 - | Knowledge International Journal
R. Peshev, M. Alexandrov, Y. Ivanov, Yordan Gogov,
Tópico(s): Virus-based gene therapy research
1996 - Elsevier BV | Journal of Virological Methods
Yordan Handzhiyski, Roumyana Mironova, Iván Ivanov,
ABSTRACTABSTRACTRecently, we have shown that the process of non-enzymatic glycosylation (glycation) affects Escherichia coli chromosomal DNA under physiological conditions in vivo. We have further demonstrated that chromosomal DNA glycation is a source of spontaneous mutations in E. coli. The present study reveals that inhibition of glycation does not necessarily lead to suppression of DNA mutability. We tested the effect of acetyl salicylic acid (ASA) on chromosomal DNA glycation and spontaneous ...
Tópico(s): Escherichia coli research studies
2009 - Taylor & Francis | Biotechnology & Biotechnological Equipment
Tópico(s): Complex Network Analysis Techniques
2021 - Procon Ltd. | Information & Security An International Journal
Yordan Hristov Ivanov, Darina Pavlova,
The dynamics of contemporary economic processes urge researchers in the marketing field to study pricing outside of its traditional role. Modern customer-oriented approaches examine price levels as an instrument which contributes to retention and attraction of clients. Retention and expansion of client base is a subject-matter of the concept of customer equity which aims at long-term enhancement of customer relationship value. This value depends directly on the price levels defined by business organizations. ...
Tópico(s): Consumer Market Behavior and Pricing
2017 - | Marketing and Branding Research
Yordan Hristov Ivanov, Darina Pavlova,
The dynamics of contemporary economic processes urge researchers in the marketing field to study pricing outside of its traditional role. Modern customer-oriented approaches examine price levels as an instrument which contributes to retention and attraction of clients. Retention and expansion of client base is a subject-matter of the concept of customer equity which aims at long-term enhancement of customer relationship value. This value depends directly on the price levels defined by business organizations. ...
Tópico(s): Consumer Retail Behavior Studies
2017 - RELX Group (Netherlands) | SSRN Electronic Journal
Yordan Kalchev, Atanaska Petrova, Gergana Lengerova, Ivan Ivanov, Mariyana Murdjeva,
Background: Elizabethkingia spp. are Gram-negative, non-spore-forming bacteria that used to be rarely encountered but now they are of growing clinical significance. Furthermore, the diagnostic challenges to identification impede the complete elucidation of their epidemiology and association with human diseases. Case report: A 64-year-old man with liver cirrhosis due to alcohol abuse presented with fatigue, abdominal swelling, and bilateral scrotal edema. A peritoneal fluid sample was cultured and ...
Tópico(s): Pancreatitis Pathology and Treatment
2022 - ID Design 2012/DOOEL Skopje | Open Access Macedonian Journal of Medical Sciences
Kiril Kolikov, Dragia Ivanov, Georgi Krastev, Yordan Epitropov, Stefan Bozhkov,
Tópico(s): Power Transformer Diagnostics and Insulation
2012 - Elsevier BV | Journal of Electrostatics
Nikolay Ivanov Kolev, Yordan Sivkov, Ekaterinoslav Sirakov,
Tópico(s): Military Defense Systems Analysis
2020 - Procon Ltd. | Information & Security An International Journal
G. Ivanov, I. Avramov, Velichka Strijkova, Yordan G. Marinov, Todor E. Vlakhov, Ekaterina Anatol’evna Bogdanova, Georgi B. Hadjichristov,
Abstract Langmuir-Blodgett (LB) monolayer films deposited from a Dipalmytoyl Phosphatidyl Ethanolamine head labelled with Nitrbenzoxadiazole (DPPE-NBD), have been studied for their ability to be used as sensing layer for chemical gas sensors. DPPE-NBD molecules are known for their similarity to bio membrane molecules. Therefore, it is expected that they can serve as a matrix for immobilization of proteins, enzymes, aptamers, while preserving their function for selective reaction with organic analytes. ...
Tópico(s): Mechanical and Optical Resonators
2021 - IOP Publishing | Journal of Physics Conference Series
George R. Ivanov, Yordan G. Marinov, Todor E. Vlakhov, Anna Amova,
Tópico(s): Advanced Chemical Sensor Technologies
2025 - IOP Publishing | Journal of Physics Conference Series
M. K. Gaidarov, M. V. Ivanov, Yordan I. Katsarov, A. N. Antonov,
Tópico(s): Quantum Chromodynamics and Particle Interactions
2025 - EDP Sciences | EPJ Web of Conferences
Petar Uchikov, Nedzhat Ali, Milena Sandeva, Веселин Попов, Atanas Ivanov, Yordan Tsenovski, Florim Selimi, Maria Kraeva,
Abstract Background: Lung cancer is the leading cause of death in men and women worldwide. The average five-year survival rate for patients with lung cancer is 22% and is significantly lower than the survival rate for other cancers. Aim: The aim of the study was to determine the five-year survival rate in women after surgery for non-small cell lung cancer. Methods: A prospective cohort study was performed on 59 operated women with primary lung cancer for the period 2011-2020 in the "Second Surgical ...
Tópico(s): Global Cancer Incidence and Screening
2022 - ID Design 2012/DOOEL Skopje | Open Access Macedonian Journal of Medical Sciences