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Journal of Renewable Materials 2020年第6期8卷 675-686页

作者： Dragomir Vassilev Nadezhda petkova Yulian Tumbarski Milena Koleva Panteley Denev Department of Physics Chemistry and EcologyTechnical University of GabrovoGabrovo5300Bulgaria Department of Inorganic and Organic Chemistry University of Food TechnologiesPlovdiv4002Bulgaria Department of Microbiology University of Food TechnologiesPlovdiv4002Bulgaria

Undenicylic acid(10:1)is known as an antifungal agent and an active ingredient of many topical medicines[1–6].The present research investigates the preparation of aliphatic esters of 10-undecylic acid with butanol and i-amyl alcohol by the conventional and ultrasound-assisted syntheses as well as the structural elucidation of the resulting compounds,by FTIR and NMR *** antimicrobial properties of the obtained 10-undecylenic esters were tested against Gram-positive bacteria(Staphylococcus aureus;Enterococcus faecalis;Listeria monocytogenes),Gram-negative bacteria(Escherichia coli;Salmonella sp.)and filamentous fungi(Penicillium sp.;Aspergillus niger;Fusarium moniliforme)using the conventional agar-well diffusion *** results demonstrated that all esters had insignificant antibacterial activity.i-Amyl-10-undecylenate and t-butyl-10-undecylenate showed activity against both Gram-positive and Gram-negative bacteria,while i-butyl-10-undecylenate and n-butyl-10-undecylenate were effective only against Gram-positive bacteria *** contrast,all 10-undecylenic esters demonstrated high antifungal activity,which was most pronounced in ***,the obtained products can be successfully used as promising antifungal agents for various pharmaceutical formulations as well as biocontrol means against plant pathogens.

关键词： 10-undecylenate alkyl esters FTIR and NMR spectroscopy antimicrobial activity

Microwave Synthesis of Inulin Acetate as Potential Bio- Based Additive for Poly(Vinyl Chloride)

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Journal of Renewable Materials 2018年第7期6卷 707-714页

作者： D.Vassilev N.petkova M.Koleva P.Denev Department“Physics Chemistry and Ecology”Technical University of Gabrovo4 Hadji Dimitar str.5300 GabrovoBulgaria Department of Organic Chemistry and Inorganic Chemistry University of Food Technologies26 Maritza blv.4002 PlovdivBulgaria

The paper presents the findings of an experimental study on the microwave synthesis (MW) of inulin acetateand its possible application as bio-additive in poly(vinyl chloride) (PVC). The obtained inulin acetate has beenidentified and characterized by spectroscopic methods. Advantages of the MW compared with the conventionalsynthesis were defined. In order to evaluate possible application of the product as bio-based additive forpolymers, effect of the inulin ester on PVC behavior and characteristics has been investigated by differentialscanning calorimetry (DSC) and deformation upon extension. Experimental results show that in concentrationrange up to 30.0 wt. % the inulin ester influences positively the properties of PVC causing effect similar toplasticizing one. At concentration over 30 wt.% the ester shows more specific behavior, which will be furtherinvestigated. Conclusions about potential application of MW synthesized inulin acetate as bio-based additive forPVC have been drawn.

关键词： Inulin esters microwave-assisted esterification poly(vinyl chloride) bio-based additive tensile properties

Microwave-Assisted Isolation and Acetylation of Inulin from Helianthus Tuberosus L Tubers

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Journal of Renewable Materials 2018年第7期6卷 671-679页

作者： Nadezhda petkova Gergana Gencheva Dragomir Vassilev Milena Koleva Albert Krastanov Panteley Denev Department of Organic Chemistry and Inorganic Chemistry University of Food Technologies26 Maritza Blvd.Plovdiv4002Bulgaria Department Physics Chemistry and EcologyTechnical University of GabrovoGabrovo5300Bulgaria Department of Biotechnology University of Food Technologies26 Maritza Blvd.Plovdiv4002Bulgaria

Jerusalem artichoke (Helianthus tuberosus L.) tubers are industrial crop considered as a promising source forinulin production. “Green” method was performed for accelerated inulin extraction from Helianthus tuberosus *** by the application of microwave irradiation. Further pretreatment of the water extract with acetone andethanol yielded inulin (20%) with purity 89% and degree of polymerization 18. Jerusalem artichoke inulin wascharacterized by FTIR and NMR spectroscopy. For the first time eco-friendly synthesis of acetylated Jerusalemartichoke inulin was performed by the reaction with acetic anhydride, without toxic solvent, but only withsodium acetate as catalyst under microwave irradiation for 60 s. The degree of acetylation (DA=2.1) and thestructure of inulin esters were confirmed by 1H and 13C NMR. The suggested microwave acetylation shortenssignificantly the esterification reaction.

关键词： Jerusalem artichoke inulin inulin acetates microwave irradiation

Physicochemical Characterization and Antimicrobial Properties of Inulin Acetate Obtained by Microwave-Assisted Synthesis

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Journal of Renewable Materials 2020年第4期8卷 365-381页

作者： Nadezhda petkova radka Arabadzhieva Dragomir Vassilev Gergana Gencheva Yulian Tumbarski Tsveteslava Ignatova-Ivanova Sevginar Ibryamova Mina Todorova Milena Koleva Panteley Denev Department of Organic Chemistry and Inorganic Chemistry University of Food TechnologiesPlovdiv4002Bulgaria Department of Physics Chemistry and EcologyTechnical University of GabrovoGabrovo5300Bulgaria Department of Microbiology University of Food TechnologiesPlovdiv4002Bulgaria Department of Biology Konstantin Preslavsky University of ShumenShumenBulgaria

Microwave-assisted irradiation was performed for esterification of chicory inulin with high degree of polymerization with acetic anhydride without a solvent only with a *** resulting esters were characterized by melting point,hydrophilic-lipophilic balance,thin-layer chromatography,ultraviolet spectroscopy,Fourier transform infrared spectroscopy(FTIR)and nuclear magnetic resonance(NMR)*** acetate demonstrated a high degree of acetylation(2.5-3.0)and presented a white,water-insoluble substance with bitter *** FTIR and NMR spectra confirmed esterification and demonstrated the incorporation of hydrophobic residue to the water soluble inulin *** capacity,water holding,oil-holding capacities,the foamability,foam stability and emulsifying properties were also *** acetate showed promising foam stability 52%for 60 min and formed stable emulsions at concentration 0.2 g/L with 50 and 80%oil *** water holding capacity was lower than the oil holding *** addition to this,for the first time,the antimicrobial potential of inulin acetate was tested against seventeen microorganisms(Gram-positive and Gram-negative bacteria,yeasts and fungi).Inulin acetate(10 mg/ml)inhibited the growth of Bacillus cereus,Escherichia coli ATCC 8739,Salmonella abony,Candida albicans and Penicillium ***,inulin acetate demonstrated antimicrobial activity at concentration 1 mg/ml against Listeria monocytogenes 863,Escherichia coli 3398,Candida albicans 8673,Fusarium oxysporum and Aspergillus *** current study demonstrated the applications of“green”synthesized inulin acetate as a foaming agent,oil-in-water emulsion stabilizer and antimicrobial substance in pharmaceutical,agricultural and cosmetic preparations.

关键词： Inulin acetates microwave irradiation FTIR and NMR spectroscopy foams emulsions antimicrobial activity

Ombitasvir, paritaprevir, ritonavir, dasabuvir and ribavirin in cirrhosis after complete destruction of hepatocellular carcinoma

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World Journal of Gastroenterology 2016年第8期22卷 2630-2635页

作者： Zahariy Krastev Deian Jelev krasimir Antonov Tanya petkova Evelina Atanasova Nadezhda Zheleva Bojidar Tomov Yana Boyanova Lyudmila Mateva Clinic of Gastroenterology University Hospital "St. Ivan Rilski"

We observed a sustained viral response(SVR) of ombitasvir/paritaprevir/ritonavir, dasabuvir and ribavirin therapy, for 12 wk, in two cases with compensated liver cirrhosis and fully destroyed early hepatocellular carcinoma(HCC). Patients were infected with hepatitis C virus(HCV) genotype 1b and were previous null responders/relapsers to interferon-alpha/ribavirin(IFN/RBV). There was a rapid suppression of HCV RNA to undetectable levels within the first two treatment weeks. SVR was achieved even after marked reduction of the RBV dose. The treatment was well tolerated. Both subjects experienced worsening of liver disease during therapy, in different patterns: severe, transient, predominantly direct hyperbilirubinemia without cytolysis(case 1) or progressive increase of aminotransferases(grade 4) without severe hyperbilirubinemia(case 2).Adverse events spontaneously resolved. The patients remained in a good clinical condition without hepatic decompensation. There was no re-occurrence of HCC. This is the first report for treatment of HCV cirrhosis after complete HCC destruction.

关键词： Ombitasvir Paritaprevir Ritonavir Dasabuvir Ribavirin Hepatitis C virus cirrhosis Hepatocellular carcinoma

Growth of Douglas-fir （Pseudotsuga menziesii （Mirb.） Franco） in the Region of Yundola Training and Experimental Forest range, Bulgaria

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Journal of Agricultural Science and Technology(B) 2015年第4期5卷 269-276页

作者： krasim.ra petkova Yavor Poryazov raisa Petrova Silviculture Department University of Forestry 10 St. Kliment Ochridski Blvd. Sofia 1797 Bulgaria Forest Management Department University of Forestry 10 St. Kliment Ochridski Blvd. Sofia 1797 Bulgaria State Forest Service--Office Platchkovtsi 17 Balkan Str. Platchkovtsi 5360 Bulgaria

The aim of the article was to study the growth of Douglas-fir plantations in the region of the Training Experimental Forest Enterprise, Yundola （Central South Bulgaria）. The study sites were three Douglas-fir plantations, ranging between 50 and 55 years of age at altitudinal range between 1,400 m and 1,600 m above sea level （masl）. The mean height, diameter at breast height, site class, stem volume as well as the mechanical resistance （H/D ratio） of Douglas-fir were measured for each plantation. The results showed that Douglas-fir had the best height growth of the studied plantations on slope facing South at altitude 1,600 masl and Douglas-fir with age 55 years old reached a mean height of 32.4 m. The average diameter at breast height of the studied plantations reaches approximately 30 cm, which shows that they are suitable for large scale wood harvesting. The average stem volume of Douglas-fir in the observed plantations up to age of 55 is within the range of 400-600 m3/ha, with an average annual volume increment from 7 m3/ha to 12 m3/ha each year. The high index of mechanical resistance （H/D ratio） indicated a risk for abiotic damages, which implicated the need for the immediate implementation of felling.

关键词： Diameter of breast height Douglas-fir plantations mean height H/D ratio stem volume.

Innovative Models of Teaching in Training of Adolescents Chess Players

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Journal of Sports Science 2016年第2期4卷 75-79页

作者： Nikolay Izov Veneta petkova Leyla Dimitrova Department of Sport University of National Sports Academy "Vassil Lerski " Sofia Studentski Grad 1700 Bulgaria

The development of computer technologies, specialized software and Interact deepens the connection between them and the chess. Its relatedness increases both on educational and training and on competitive level. The contemporary training of adolescents players has very unified character and a comprehensive innovation methodology would be applicable to players, who are different at strength and age. Increasing the massiveness in junior chess implies a higher quality of coaching work, related to the use of IT innovation and modem software chess products. HYPOTHESIS： The use of computer innovation would increase the effectiveness of the educational and training process in chess. OBJECTIVE： To prove the improvement of the effectiveness of the educational and training process through the development and testing of innovative education model for adolescents players with predominantly using of specialized chess software analytical module and web-based learning. METHODOLOGY： Pedagogical experiment, expert evaluation, questionnaire survey, sports pedagogical testing and mathematical and statistical methods. CONCLUSION： The experimental methodology for the training of adolescents players by using specialized chess software, internet and web-based forms of training leads to higher efficiency of the training sessions and higher results, compared to traditional ones.

关键词： Computerization chess software chess training.

Renal cell carcinoma presented with a rare case of icteric Stauffer syndrome:A case report

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World Journal of Clinical Cases 2022年第25期10卷 9087-9095页

作者： Dimitar R Popov krasimir A Antonov Evelina G Atanasova Christo P Pentchev Lyuben M Milatchkov Maria D petkova krasimir G Neykov Rosen K Nikolov Medical University of Sofia Sofia 1431Bulgaria Clinic of Gastroenterology University Hospital’St.Ivan Rilski’Sofia 1431Bulgaria Clinic of Urology National Oncology HospitalSofia 1756Bulgaria

BACKGROUND Paraneoplastic syndromes remain poorly understood and manifest as multifaceted clinical symptoms,making their diagnosis *** can be observed in various *** rare cases,it can be a paraneoplastic manifestation,most often associated with renal cell carcinoma and other urogenital tumors,as well as with bronchial *** classical form of Stauffer syndrome presents with a reversible anicteric increase of cholestatic liver function tests,thrombocytosis,coagulation impairment,and hepatosplenomegaly,without any proven hepatobiliary obstruction or *** SUMMARY We report a patient who presented with elevated liver enzymes,cholestatic jaundice,weight loss and pruritus,in whom renal cell carcinoma was incidentally found during ***,laboratory,and imaging tests excluded primary hepatic cause or metastatic *** and laboratory abnormalities reversed completely a few months after *** case is an example of the many sides of renal cell carcinoma,and it focuses the clinicians’attention on the differential diagnosis of cholestasis,including Stauffer syndrome and its ***,the correct diagnosis can be straightforward and the associated malignancy can be treated *** cases should be followed up with a multidisciplinary ***(IL)-6 is proposed to contribute to the pathophysiology of the *** probable mechanism is proinflammatory activity by the IL-6 cytokine,causing elevation of C-reactive protein and haptoglobin and inhibition of hepatobiliary transporter gene expression,impairing biliary *** Despite being rare,Stauffer syndrome is a potentially reversible paraneoplastic condition,when the primary cause is *** syndrome should be considered by clinicians because of the remediable liver disturbance,after successful treatment of the underlying malignancy.

关键词： Jaundice Cholestasis Renal cell carcinoma Stauffer syndrome Case report

Study of a Single-Phase Series Active Power Filter with Hysteresis Control

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Journal of Energy and Power Engineering 2012年第10期6卷 1635-1642页

作者： Mihail Antchev Mariya petkova Hristo Antchev Vanjo Gourgoulitsov Stanimir Valchev Department of Power Electronics Technical University Sofia 1000 Bulgaria Power Engineering and Electronics College Technical University Sofia 1000 Bulgaria Faculdade de Ciencias e Tecnologia (FCT) of Universidade NOVA de Lisboa (UNL) Caparica PT 2928-516 Portugal

The paper presents results from a study of a series-connected single-phase APF （active power filter） with a control system based on hysteresis control, both with and without limitation of the maximum switching frequency. The general purpose of the series APF is to eliminate the low order harmonics of the source （grid） voltage. The filter operation at limited and unlimited maximum switching frequency is explained and it is described using building blocks and time diagrams illustrating the tracking down of the reference curve. Waveforms from the computer simulation and waveforms from the experimental tests of the filter are presented also for the two situations. Operations at limited and unlimited maximum switching frequency are compared regarding the quality of the voltage across the load, the complexity of the implementation of the control system, and the electromagnetic compatibility. The investigation proved capability of the series APF to achieve its general purpose using the hysteresis control methods studied （limited and unlimited switching frequency）.

关键词： Series active power filter APF hysteresis control frequency limitation.

Vector Control-Development and Improvement of the Modern Chemical Insecticides

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Journal of Pharmacy and Pharmacology 2015年第1期3卷 1-8页

作者： Ivan Popivanov Tanya petkova Victoria Doycheva Tzetza Doychinova Ivelin Angelov DimitarShalamanov Department of Military Medicine Military Medical Academy Sofia 1606 Bulgaria Department of lnfectious diseases Epidemiology Parasitology and Tropical Medicine Medical University Pleven 5800 Bulgaria Department of Epidemiology Medical University Sofia 1431 Bulgaria

The transition from empirical and applied approach toward a scientific approach in modem medical disinsection is a result of the discoveries of the organic chemistry. The most intensive used substance in this fteld-DDT （dichlorodiphenyltrichloroethane） is introduced during World War II and contributes to world practical epidemiology just as antibiotics in clinical medicine. However, after the 70s, this substance was placed under a ban, because of the accumulated evidence of many adverse health and environmental impacts globally. Improvement of the insecticides after ＂DDT-era＂ is represented by the introduction of organophosphate and carbamate insecticides in the 1960s. Their broad application is determined by better ecotoxicological characteristics. The advance in biotechnology after the 1980s establishes the new class of insecticides-synthetic pyrethroids. Nowadays they are basic for the insect control. Pyrethroids are characterized by selective impact on insects with much less impact on warm-blooded animals and the environment. Insecticides from the newest class insect growth regulators realize their mode of activity by interfering with chitin metabolism and thus prevent an insect from reaching maturity. These substances have extremely low toxicity, which makes them very promising for the treatment of civilian and military facilities.

关键词： Vector control insecticides development.