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Sol-gel synthesis, surface and magnetic properties of nanocrystalline SmAlO_3

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Journal of Rare Earths 2010年第4期28卷 602-605页

作者： dimitar Petrov Bogdan Angelov Vasil Lovchinov Department of Inorganic and Physical Chemistry University of Food Technologies 26 Maritsa Blvd. 4002 Plovdiv Bulgaria Institute of Solid State Physics Bul garian Academy of Sciences 72Tzarigradsko Chaussee Blvd. 1784 Sofia Bulgaria

Nanocrystals of single-phase samarium monoaluminate (SmAlO3) were synthesized and studied for the first time. Malic acid was employed as a new complexing agent in the sol-gel process. The material was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDS), specific surface area and density. The lowest size of the nanoparticles was about 50–60 nm and some of them formed agglomerates. The binding energies of core-level electrons of Sm (3d, 4d, 4f, ...

关键词： SmAlO3 nanocrystals surface properties magnetic susceptibility rare earths

Landscape alteration affects the demography of an endangered avian predator by reducing the habitat quality

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Avian Research 2022年第2期13卷 194-201页

作者： dimitar Demerdzhiev Dobromir Dobrev Georgi Popgeorgiev Stoycho Stoychev Bulgarian Society for the Protecaon of Birds/Birdlife Bulgaria 5 Leonardo Da Vinci Str.Plovdiv4000Bulgaria National Museum of Natural History Department of ZoologySofiaBulgaria

Habitat transformation is identified as major threat to biodiversity loss globally,affecting threatened *** in land use can alter the abundance and distribution of birds of prey by affecting habitat availability and *** this study,we used multivariate analyses to investigate the effect of habitat alteration on the demography of a declining Eastern Imperial Eagle(Aqufla heliaca),making assumptions for future population *** used the Generalized Linear Mixed Models with Poisson distribution and Log link function,searching a relationship between the demographic parameters and the landscape structure and possible effects of *** our study area,habitat change affected dramatically permanent grasslands,shrinking their *** we expected,the share of grasslands in eagles’territories significantly affected occupancy rate,but not productivity and breeding *** found that occupancy rate decreased significantly,while productivity and breeding frequency showed no *** the effect of habitat alteration on Eastern Imperial Eagle demography,we found out that territory quality was a more powerful factor driving the response of a top predator to the alteration of favorite foraging *** the habitat quality in source territories had a significant positive effect on eagle *** found that simple rules to predict adverse agricultural impact on territory abandonment or breeding productivity of a top predator were not *** results could be used for planning conservation of other large territorial raptors,facing the same type of threat.

关键词： Eastern imperial eagle Habitat transformation Population dynamics Raptor demography Source-sink system

Self-healing effect of ceria electrodeposited thin films on stainless steel in aggressive 0.5 mol/L NaCl aqueous solution

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Journal of Rare Earths 2015年第11期33卷 1212-1227页

作者： Desislava Guergova Emilia Stoyanova dimitar Stoychev Ivalina Avramova Plamen Stefanov "Rostislaw Kaischew" Institute of Physical Chemistry Bulgarian Academy of Sciences Institute of General and Inorganic Chemistry Bulgarian Academy of Sciences

The self-healing effect of electrochemically deposited CeO2-Ce2O3 films on stainless steel OC404（SS） in 0.5 mol/L NaCl solution was studied. It was established that the corrosion potential of the steel, after covering it with CeO2-Ce2O3 layer and thermal treatment（i.e. potential of the system CeO2-Ce2O3/SSt.t.）, was shifted sharply to a considerably more positive value, while the corrosion current was reduced noticeably. The X-ray photoelectron spectroscopy（XPS）, energy dispersive spectroscopy（EDS） and scanning electron microscopy（SEM） analyses on the observed scratched surface area of the system CeO2-Ce2O3/SSt.t., after exposure of investigated specimens to 0.5 mol/L NaCl corrosion media, showed partial accumulation of ceria, as well as remarkable increase in the concentrations of oxides of Al, Cr and Fe, on the mechanically revealed steel surface. On the basis of the obtained results one could conclude that the secondary passive oxide/hydroxide films, formed after a definite time interval of exposure to corrosion media, acted as barriers, hindering the corrosion processes in active zones. A hypothesis was put forward about the mechanism of self-repairing oxide layers on the steel surface and their corrosion protection effect respectively.

关键词： stainless steel ceria films corrosion self-healing effect rare earths

Mechanochemical Synthesis and Characterization of Nanocrystalline Copper-Cobalt Ferrites

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Acta Metallurgica Sinica(English Letters) 2015年第3期28卷 367-372页

作者： Nikolay Velinov dimitar Dimitrov Kremena Koleva Krassimir Ivanov Ivan Mitov Institute of Catalysis Bulgarian Academy of Sciences Department of Chemistry Agricultural University

Nanocrystalline copper-cobalt ferrites with composition Cu_（1-x）Co_xFe_2O_4,where x = 0.2 and 0.8,were synthesized by mechanochemical treatment of co-precipitated *** ferrite powders were characterized by XRD and Mossbauer *** proved obtaining of spinel ferrites with crystallite size smaller than 10 *** of crystallite size of samples with increasing of mechanochemical treatment duration was established,*** properties of obtained ferrites were tested in reactions of oxidation of CO,methanol and dimethyl *** catalytic activity of nanocrystalline copper-cobalt ferrites toward CO and CH_3OH（about 100% conversions of CO and CH_3OH at 160 ℃）and moderate activity toward（CH_3）_2O oxidation were *** results obtained revealed that the Co/Cu atomic ratio is an important factor determinant the behavior of catalysts toward methanol and DME oxidation.

关键词： Mechanochemical synthesis Nanocrystalline Ferrites Mossbauer spectroscopy Catalysis

Diversifying Resistance Mechanisms in Cereal Crops Using Microphenomics

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Plant Phenomics 2023年第1期5卷 1-5页

作者： Peter M.Dracatos Stefanie Lück dimitar K.Douchkov Department of Animal Plant and Soil SciencesAgriBioLa Trobe UniversityBundooraVIC 3086Australia Leibniz Institute of Plant Genetics and Crop Plant Research(IPK)Gatersleben Corrensstrasse 306466 Seeland OT GaterslebenGermany

hole-grain cereals,including wheat,barley,oat,rye,corn,rice,millet,and triticale,are a rich source of calories,essential vitamins,minerals,and phytochemicals that both nourish and protect humans and animals from diseases such as heart attack and cancer[1].However,susceptibility to foliar diseases caused by necrotrophic or biotrophic fungal pathogens continues to reduce yield potential or lead to total crop failure and famine in developing nations[2].Historically,foliar diseases of cereals have been controlled using either fungicide treatment[3]or plant breeding[4].

关键词： breeding cereal corn

Increased intestinal permeability in inflammatory bowel diseases assessed by iohexol test

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World Journal of Gastroenterology 2011年第17期17卷 2211-2215页

作者： Vanya A Gerova Simeon G Stoynov dimitar S Katsarov Dobrin A Svinarov Clinical Center of Gastroenterology University Hospital Queen JoannaMedical UniversitySofia 1527Bulgaria Central Laboratory of Therapeutic Drug Monitoring and Clinical Pharmacology University Hospital AlexandrovskaMedical UniversitySofia 1431Bulgaria

AIM:To study intestinal permeability(IP) and its relationship to the disease activity in patients with inflammatory bowel diseases(IBD)-Crohn's disease(CD) and ulcerative colitis(UC).METHODS:Fifty-eight patients with active IBD(32 with CD and 26 with UC) and 25 healthy controls consented to participate in the *** clinical activity of CD was estimated using the Crohn's Disease Activity Index(CDAI),and the endoscopic activity of UC using the Mayo scoring *** was assessed by the rise in levels of iohexol,which was administered orally(25 mL,350 mg/mL) 2 h after *** and six hours later serum(SIC mg/L) and urine(UIC g/mol) iohexol concentrations were determined by a validated HPLC-UV ***:In the CD group,SIC values at 3 h(2.95 ± 2.11 mg/L) and at 6 h after ingestion(2.63 ± 2.18 mg/L) were significantly higher compared to those of healthy subjects(1.25 ± 1.40 mg/L and 1.11 ± 1.10 mg/L,respectively,P < 0.05).UIC(g/mol) values were also higher in patients,but the differences were significant only for UIC at 6 *** positive correlation(P < 0.05) was found between the CDAI and IP,assessed by SIC at 3 h(r = 0.60) and 6 h(r = 0.74) after the *** comparison to controls,SIC and UIC of UC patients were higher in the two studied periods,but the differences were significant at 6 h *** higher values of SIC(P < 0.05) were found in patients with severe endoscopic activity of UC compared to those of patients with mild and moderate activity(3.68 ± 3.18 vs 0.92 ± 0.69 mg/L).CONCLUSION:Serum levels of iohexol at 3 h and 6 h after its ingestion reflect increased IP,which is related to the disease activity in patients with IBD.

关键词： Intestinal permeability Iohexol test Inflammatory bowel disease Crohn's disease Ulcerative colitis

Habitat preferences of diurnal raptors in relation to human access to their breeding territories in the Balkan Mountain Range,Bulgaria

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Avian Research 2021年第3期12卷 307-316页

作者： Nadejda Djorgova dimitar Ragyov Valko Biserkov Jordan Biserkov Boris P.Nikolov Institute of Biodiversity and Ecosystem Research Bulgarian Academy of Sciences2 Gagarin Street1113 SofiaBulgaria

Background:In this study we examined the habitat preferences of three diurnal raptors in relation to human *** aimed to identify the selection of breeding habitat by the Golden Eagle(Aquila chrysaetos),the Long-legged Buz-zard(Buteo rufinus),and the Peregrine Falcon(Falco peregrinus)in response to site accessibility by humans,and in turn,the response of these species to human ***:Data about the nest locations were *** and maps were created using ***“least cost path”was defined using the Cost Path ***:The lowest values of the Cost Path were established for Long-legged Buzzard and the highest values were estimated for Golden *** Cost Path values for Peregrine Falcon were ***:The Long-legged Buzzard could be considered as the most tolerant to human presence in its breeding *** Golden Eagle have the lowest degree of tolerance and the Peregrine Falcon is ranked in an intermedi-ate position compared to the other two species,but closer to Golden Eagle.

关键词： Anthropogenic impact Golden Eagle Least cost path Long-legged Buzzard Peregrine Falcon

Role of GM3 ganglioside in the pathology of some progressive human diseases and prognostic importance of serum anti-GM3 antibodies

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BIOCELL 2021年第6期45卷 1485-1494页

作者： VERA KOLYOVSKA SONYA IVANOVA DESISLAVA DRENSKA dimitar MASLAROV RENETA TOSHKOVA Institute of Experimental Morphology Pathology and Anthropology with MuseumBulgarian Academy of SciencesSofia1113Bulgaria University Hospital for Neurology and Psychiatry“St.Naum” Sofia1797Bulgaria University First MHAT-Sofia “St.John Krastitel”Neurology ClinicSofia1142Bulgaria Medical University of Sofia Medical College“Y.Filaretova”Sofia1606Bulgaria

Glycosphingolipids(gangliosides)have been characterized as important biological molecules with a key role as regulators in many physiological processes on cellular,tissue,organ,and organism *** deviations in their normal amounts,production,and metabolism are very often related to the development of many multi-factor socially important ***3 ganglioside,as a small molecule,plays important roles in the cascade regulatory pathways in the pathology of many disorders like neurodegenerative diseases,autoimmune diseases,inflammation,diabetes,malignant transformation,and *** GM3 and its derivatives are membrane-bound glycosphingolipids composed of an oligosaccharide head structure containing one sialic acid *** molecules transduce signals involved in cell surface events,including the phosphorylation of transmembrane *** ganglioside is the most widely distributed among tissues,and it serves as a precursor for most of the more complex ganglioside ***3 inhibits the function of fibroblast growth factor receptor,and cell growth is regulated by GM3-enriched ***3 is thought to inhibit immunologic functions,such as the proliferation and production of cytokines by T *** the other hand,the anti-ganglioside antibodies(AGAs)are important in many acquired demyelinating immunemediated neuropathies,like Multiple sclerosis(MS),Guillain–Barrésyndrome(GBS)and its variation,Miller–Fisher syndrome(MFS)and could be suggested as important diagnostic and prognostic markers about the describe diseases and their *** show that the complexes of anti-ganglioside antibodies to GM3(detected by ELISA)may be useful diagnostic and prognostic tool markers for autoimmune diseases,neurodegenerative disorders,malignancy,diabetes,and *** pilot studies suggest increased serum IgG anti-GM3 antibodies titers in patients with secondary progressive MS(SPMS),throat cancer,elder people with diabetes(89–96 years),old Lewis rat

关键词： Biomarkers Serum GM3 Serum anti-GM3 antibodies ELISA

Liver dysfunction as a cytokine storm manifestation and prognostic factor for severe COVID-19

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World Journal of Hepatology 2021年第12期13卷 2005-2012页

作者： Gergana Taneva dimitar Dimitrov Tsvetelina Velikova Department of Gastroenterology Sveta Sofia HospitalSofia 1618Bulgaria Department of Clinical Immunology University Hospital LozenetzSofia 1407Bulgaria Medical Faculty Sofia University St.Kliment OhridskiSofia 1407Bulgaria

patients with or without preexisting liver disorders,posing a significant complication and mortality *** coronavirus disease 2019(COVID-19),abnormal liver function is typically ***,liver injury may occur because of the treatment as ***,cytokine storm,and hypoxia were identified as the three major factors contributing to liver damage during ***,raised liver enzymes during hospitalizations may be attributed to medications used,as well as sepsis and *** a result,the proportion of hospitalized patients afflicted with COVID-19 and pathological liver biomarkers varies from 14%to 53%.Aminotransferases and bilirubin are found most often ***,increased gamma-glutamyltransferase,alkaline phosphatase,and decreased serum albumin levels are ***,although there is no specific treatment for COVID-19,many of the drugs used to treat the infection are *** this mini-review,we focus on how liver dysfunction can be one of the features associated with the COVID-19 cytokine ***,data show that liver injury can be an independent predictor of severe COVID-19,the need for hospitalization,and death.

关键词： Liver dysfunction Liver damage Cytokine storm Prognostic factor COVID-19 Severe COVID-19 SARS-CoV-2 Aspartate aminotransferase Alanine aminotransferase Bilirubin Interleukin-6