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Photometric observations and light curve solutions of the W UMa stars NSVS 2244206,NSVS 908513,CSS J004004.7+385531 and VSX J062624.4+570907

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Research in Astronomy and Astrophysics 2016年第9期16卷 15-22页

作者： Diana Petrova Kiurkchieva Velimir Angelov Popov Doroteya Lyubenova Vasileva Nikola ivanov Petrov Department of Physics Shumen University115Universitetska Str.1712 ShumenBulgaria IRIDA Observatory 17A Prof.Asen Zlatarov Str.SofiaBulgaria Institute of Astronomy and National Astronomical Observatory Bulgarian Academy of Sciences72Tsarigradsko Shose Blvd.1784 SofiaBulgaria

Photometric observations in Sloan 9＇ and i＇ bands of four W UMa stars, NSVS 2244206, NSVS 908513, CSS J004004.7＋385531 and VSX J062624.4＋570907, are presented. The light curve solutions reveal that all targets have overcontact configurations with fillout factors within 0.15-0.26. Their components are G-K spectral types and are almost in thermal contact. They are also relatively close in size and luminosity： the radius ratios r2/r1 are within 0.75-0.90; the luminosity ratios 12/11 are within 0.53-0.63. The results of the light curve solution of CSS J004004.7＋385531 imply the weak limb-darkening effect of its primary component and possible presence of additional absorbing features in the system.

关键词： methods data analysis -- stars fundamental parameters -- stars binaries eclipsing individ-ual (NSVS 2244206, NSVS 908513, CSS J004004.7+385531, VSX J062624.4+570907)

Observations and light curve solutions of a selection of middle-contact W UMa binaries

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Research in Astronomy and Astrophysics 2018年第4期18卷 105-114页

作者： Diana Petrova Kjurkchieva Velimir Angelov Popov Doroteya Lyubenova Vasileva Nikola ivanov Petrov Department of Physics Shumen University IRIDA Observatory Rozhen NAO Institute of Astronomy and NAO Bulgarian Academy of Sciences

Photometric observations in Sloan g′and i′ bands of W UMa binaries NSVS 4340949,T-Dra0–00959,GSC 03950–00707,NSVS 4665041,NSVS 4803568,MM Peg,MM Com and NSVS4751449 are *** light curve solutions revealed that the components of each target are of G and K spectral *** binaries of the sample have middle-contact configurations whose fillout factors are within the range 0.2–*** only exception is NSVS 4751449 which is in deeper contact（fillout factor of 0.55）.It precisely obeys the relation between mass ratio and fillout factor for deep,low mass ratio overcontact *** of the eclipses of almost all targets（except MM Peg）is an occultation and their photometric mass ratios and solutions could be accepted with *** found that the target components have almost equal temperatures but differ considerably in size and *** components of the partially-eclipsed MM Peg have close *** solutions reveal that NSVS 4340949,T-Dra0–00959,NSVS 4803568 and MM Com are of W subtype while GSC 03950–00707,NSVS 4665041,MM Peg and NSVS 4751449 are of A *** subclassification is well-determined for all totallyeclipsed *** targets confirm the trends in which W-subtype systems have smaller periods and lower temperatures than A subtype binaries.

关键词： binaries close — binaries eclipsing — stars fundamental parameters — stars late-type

Structure-activity relationship in water-gas shift reaction over gold catalysts supported on Y-doped ceria

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Journal of Rare Earths 2019年第4期37卷 383-392页

作者： Tatyana Tabakova Lyuba Ilieva Ivan ivanov Maela Manzoli Rodolfo Zanella Petya Petrova Zbigniew Kaszkur Institute of Catalysis Bulgarian Academy of Sciences Department of Drug Science and Technology & Centre for Nanostructured Interfaces and Surfaces University of Turin Centro de Ciencias Aplicadas y Desarrollo Tecnologico Universidad Nacional Autonoma de Mexico Institute of Physical Chemistry PAS

The utilization of pure hydrogen as an energy source in fuel cells gave rise to renewed interest in developing active and stable water-gas shift catalysts. Gold catalysts have proven to be very efficient for water-gas shift reaction at low temperature. The aim of the present study was to investigate the effect of:(i) different preparation methods(impregnation and coprecipitation) to obtain a modified ceria support,and(ii) the amount of Y_2 O_3(1.0 wt%, 2.5 wt%, 5.0 wt% and 7.5 wt%) as dopant on the water-gas shift activity of Au/CeO_2 catalysts. An extended characterization by means of S_(BET), XRD, HRTEM/HAADF, FTIR,H_2-TPR and CO-TPR measurements in combination with careful evaluation of the catalyst behavior allowed to shed light on the parameters governing the water-gas shift activity. The catalysts show very high activity(>90% CO conversion) in the temperature range 180-220 ℃,with a slightly better performance of the gold catalysts on supports prepared by impregnation. The decreased activity with increasing Y_2 O_3 concentration is related to the hindering of oxygen mobility due to ordering of surface oxygen vacancies in vicinity of segregated Y^(3+). The effect of catalyst pre-treatments and the stability of the best performing samples were examined as well.

关键词： Gold catalyst Water gas shift reaction Doped ceria Yttrium Hydrogen production Rare earths

Results of the Main Phase of Ion Separation in the Process of Plasma-Optical Mass Separation

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Plasma Science and Technology 2015年第10期17卷 862-868页

作者： V.M.BARDAKOV S.D.ivanov A.V.KAZANTSEV N.A.STROKIN Institute for Physics and Technology Irkutsk State Technical University

This paper presents separation results of a mixture of nitrogen, argon and krypton ions in the process of plasma-optical mass separation on the POMS-E-3 separator model. We determined the behavior of the separation with a change in the value of magnetic field induction in the azimuthator and in the degree of compensation of the spatial charge in ion flows. An analysis is performed for experimental data by correlation with the results of a theoretical study and numerical experiments. The objectives of future experiments are outlined.

关键词： plasma-optical mass separation plasma accelerator trajectories spatial charge

Liquid Liver Biopsy for Disease Diagnosis and Prognosis

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Journal of Clinical and Translational Hepatology 2023年第7期11卷 1520-1541页

作者： Desislava K.Tsoneva Martin N.ivanov Manlio Vinciguerra Department of Medical Genetics Medical University of VarnaVarnaBulgaria Department of Stem Cell Biology and Transplantology Research InstituteMedical University of VarnaVarnaBulgaria Department of Anatomy and Cell Biology Research InstituteMedical University of VarnaVarnaBulgaria Faculty of Health Liverpool John Moores UniversityLiverpoolUnited Kingdom

Liver diseases are a major burden worldwide,the scope of which is expected to further grow in the upcoming *** relevant liver dysfunction-related blood markers such as alanine aminotransferase and aspartate aminotransferase have limited ***,liver biopsy remains the gold standard for several liver-related pathologies,posing a risk of complication due to its invasive *** biopsy is a minimally invasive approach,which has shown substantial potential in the diagnosis,prognosis,and monitoring of liver diseases by detecting disease-associated particles such as proteins and RNA molecules in biological *** are the core components of the nucleosomes,regulating essential cellular processes,including gene expression and DNA *** cell death or activation of immune cells,histones are released in the extracellular space and can be detected in *** are stable in circulation,have a long half-life,and retain their post-translational ***,we provide an overview of the current research on histone-mediated liquid biopsy methods for liver diseases,with a focus on the most common detection methods.

关键词： Liquid biopsy,Histones NAFLD/MAFLD Chronic liver disease Hepatocellular carcinoma

Mapping conformational changes on bispecific antigen-binding biotherapeutic by covalent labeling and mass spectrometry

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Journal of Pharmaceutical Analysis 2024年第8期14卷 1238-1246页

作者： Arnik Shah Dipanwita Batabyal Dayong Qiu Weidong Cui John Harrahy Alexander R.ivanov Amgen Inc. CambridgeMA02141USA Barnett Institute of Chemical and Biological Analysis Department of Chemistry and Chemical BiologyNortheastern UniversityBostonMA02115USA Amgen Inc. Thousand OaksCA91320USA Sanofi WalthamMA02451USA

Biotherapeutic's higher order structure(HOS)is a critical determinant of its functional properties and conformational ***,we evaluated two covalent labeling methods:diethylpyrocarbonate(DEPC)-labeling and fast photooxidation of proteins(FPOP),in conjunction with mass spectrometry(MS),to investigate structural modifications for the new class of immuno-oncological therapy known as bispecific antigen-binding biotherapeutics(BABB).The evaluated techniques unveiled subtle structural changes occurring at the amino acid residue level within the antigen-binding domain under both native and thermal stress conditions,which cannot be detected by conventional biophysical techniques,e.g.,near-ultraviolet circular dichroism(NUV-CD).The determined variations in labeling uptake under native and stress conditions,corroborated by binding assays,shed light on the binding effect,and highlighted the potential of covalent-labeling methods to effectively monitor conformational changes that ultimately influence the product *** study provides a foundation for implementing the developed techniques in elucidating the inherent structural characteristics of novel therapeutics and their conformational stability.

关键词： Covalent labeling/footprinting Liquid chromatography-mass spectrometry Fast photooxidation of proteins Diethylpyrocarbonate Higher order structure characterization

Effect of the addition of rare earths on the activity of alumina supported copper cobaltite in CO oxidation, CH_4 oxidationand NO decomposition

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Journal of Rare Earths 2015年第4期33卷 382-390页

作者： B.ivanov I.Spassova M.Milanova G.Tyuliev M.Khristova Institute of General and Inorganic Chemistry Bulgarian Academy of Sciences Faculty of Chemistry and Pharmacy Sofia University Institute of Catalysis Bulgarian Academy of Sciences

The effect of the addition of small amounts of rare earths （Ln=La, Ce, Nd and Gd） to alumina supported copper-cobalt spinel oxide on the catalysts efficiency in CO and CH4 oxidation and in NO decomposition was investigated. Samples of Ln/CuCo/AI catalyst were prepared and characterized by X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, atomic absorption spectroscopy （AAS）, scanning electron mieroscopy-energy dispersive spectroscopy （SEM-EDS）, H2-temperature-programmed reduc- tion （H2-TPR）, electron paramagnetic resonanee （EPR） spectroscopy and low temperature nitrogen adsorption, The results showed that the addition of rare earths changed the surface state of the alumina supported copper-cobalt spinel catalyst. As a result, partial re- duction of copper species was observed as well as migration of these species between the surface and the bulk. The Ln/CuCo/A1 catalysts behaved differently in oxidation and reduction processes. In oxidation processes where oxide structure was important, Ce/CuCo/A1 and Nd/CuCo/A1 were the most active catalysts. The catalyst Ce/CuCo/AI was the most active in the oxidation reactions because of the availability and favorable surface distribution of the redox couples Cu＋/Cu2＋ and Ce3＋/Ce4＋. In NO decompostion, Ln-modified catalysts significantly improved the selectivity of the process to N2.

关键词： copper cobaltite NO decomposition CO oxidation CH4 oxidation rare earths

Artificial intelligence applications in finance:a survey

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Journal of Management Analytics 2023年第4期10卷 676-692页

作者： Xuemei Li Alexander Sigov Leonid Ratkin Leonid A.ivanov Ling Li Department of Information Technology and Decision Sciences Strome College of BusinessOld Dominion UniversityNorfolkVAUSA Department of Electronic Machinery University of Electronic Science and Technology of ChinaChengduPeople’s Republic of China Russian Technological University MoscowRussian Federation Russian Academy of Sciences MoscowRussian Federation Russian Academy of Engineering MoscowRussian Federation

Finance is in our daily *** invest,borrow,lend,budget,and save *** also provides guidelines for corporation and government spending and revenue *** statistical solutions such as regression,PCA,and CFA have been widely used in financial forecasting and *** the increasing interest in artificial intelligence in recent years,this paper reviews the Artificial Intelligence(AI)techniques in the finance domain systematically and attempts to identify the current AI technologies used,major applications,challenges,and trends in *** explores AI-related articles in Finance in IEEE Xplore and EI compendex *** suggest AI has been engaged in Finance in financial forecasting,financial protection,and financial analysis and decision-making *** forecasting is one of the main sub-fields of Finance affected by AI *** major AI technology used is supervised *** learning has gained popular in recent *** could be used to address some emerging topics.

关键词： machine learning artificial intelligence finance

Post-liver transplant biliary complications:Current knowledge and therapeutic advances

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World Journal of Hepatology 2021年第1期13卷 66-79页

作者： Irina Boeva Petko ivanov Karagyozov Ivan Tishkov Department of Interventional Gastroenterology Acibadem City Clinic Tokuda HospitalSofia 1407Bulgaria Department of Interventional Gastroenterology Clinic of GastroenterologyAcibadem City Clinic Tokuda HospitalSofia 1407Bulgaria

Liver transplantation is the current standard of care for end-stage liver disease and an accepted therapeutic option for acute liver failure and primary liver *** the remarkable advances in the surgical techniques and immunosuppressive therapy,the postoperative morbidity and mortality still remain high and the leading causes are biliary complications,which affect up to one quarter of *** most common biliary complications are anastomotic and non-anastomotic biliary strictures,leaks,bile duct stones,sludge and *** the absence of a recommended treatment algorithm many options are available,such as surgery,percutaneous techniques and interventional *** the last few years,endoscopic techniques have widely replaced the more aggressive percutaneous and surgical *** retrograde cholangiography is the preferred technique when duct-to-duct anastomosis has been ***,new devices and techniques have been developed and this has led to a remarkable increase in the success rate of minimally invasive *** the mechanisms of biliary complications helps in their early recognition which is the prerequisite for successful *** endoscopic therapy is essential for the reduction of morbidity and mortality in these *** article focuses on the common post-transplant biliary complications and the available interventional treatment modalities.

关键词： Post-transplant biliary complications Endoscopic retrograde cholangiopancreatography Cholangioscopy Percutaneous biliary interventions Liver transplantation Living-donor liver transplantation