Bulgarian Academy of Sciences

About: Bulgarian Academy of Sciences is a government organization based out in Sofia, Bulgaria. It is known for research contribution in the topics: Catalysis & Coupling constant. The organization has 17989 authors who have published 36276 publications receiving 642820 citations. The organization is also known as: Bulgarian Academy of Sciences，簡稱：BAS & Balgarska Akademiya na Naukite.

Propolis produced in Bulgaria and Mongolia : phenolic compounds and plant origin

Abstract: Des bourgeons de Populus nigra, P italica, P tremula, Betula verrucosa, Aesculus hippocastanum, Alnus glutinosa, Fraxinus excelsior, Salix alba, Prunus padus et Prunus cerasus ainsi que des echantillons de propolis ont ete preleves dans la region de Sofia, Bulgarie. En Mongolie, de la propolis et des bourgeons de Populus suaveolens ont ete recoltes dans la region d'Ulan Bator, les peupliers de cette espece etant les seusl arbres a pousser dans cette region. Les secretions des bourgeons, apres une breve extraction a l'acetone, ont ete analyses en chromatogrphie sur couche mince et chromatographie liquide haute pression. Seules les secretions de bourgeons de Populus nigra, P italica et P tremula ont fourni des phenols semblables a ceux trouves dans le propolis bulgare

Glass formation and structure of glasses in the V2O5MoO3Bi2O3 system

Abstract: The glass formation region in the V2O5MoO3Bi2O3 system was investigated by the roller-quenching method. Low melting glasses were obtained in the MoO3- and V2O5-rich compositions. Characterization of the glasses was made by X-ray diffraction, differential thermal analysis (DTA) and IR spectroscopy. According to the DTA data, the glass transformation temperature, Tg, for the different compositions varied between 200 and 290°C and the cystallization temperature, TX, was within the interval of 225–330°C. Structural models for glasses of th MoO3Bi2O3 and V2O5Bi2O3 systems were suggested on the basis of IR spectral investigations, by comparing with known crystalline structures. It was shown that the glasses possess [MoO4], [MoO6], [VO4], and [BiO6] groups as basic structural units.

Drought stress effects on Rubisco in wheat: changes in the Rubisco large subunit

Abstract: The leaf protein pattern from drought-tolerant and drought-sensitive wheat varieties subjected to severe soil drought but with the possibility for recover from stress was studied by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). The spots representing Rubisco large subunit (RLS) were identified using polyclonal antibodies against Rubisco and immunoblotting. Some qualitative and quantitative differences in the 2D-PAGE protein map of wheat varieties were revealed under drought conditions. Three days recovery of wheat plants were not enough for restoring RLS quantity to the level of controls after 7 days drought, especially in the drought-sensitive variety Miziya. There are contradictory data in the literature concerning increased or diminished RLS level in drought stressed plants. A comparison of RLS after SDS-PAGE and 2D-PAGE was made. The revealed protein pattern depended on the presence or absence of protease inhibitors in the extraction buffer, on the procedure of extraction, and on the degree of stress.

The effect of ceria content on the performance of Pt/CeO2/Al2O3 catalysts in the partial oxidation of methane

Abstract: The effect of CeO2 loading (1–20 wt.%) on the properties and catalytic behaviors of CeO2–Al2O3-supported Pt catalysts on the partial oxidation of methane was studied. The catalysts were characterized by SBET, X-ray diffraction (XRD), temperature-programmed reduction (TPR) and oxygen storage capacity (OSC). XRD and TPR results showed that the pretreatment temperature of the support influences on the amount of CeO2 with fluorite structure. The pretreatment temperature of the support and CeO2 loading influenced the morphology of Pt. OSC analysis showed a significant increase in the oxygen storage capacity per weight of CeO2 for samples with high CeO2 loading (12 and 20 wt.%). TPR analyses showed that the addition of Pt promotes the reduction of CeO2. This effect was more significant for the catalysts with high CeO2 loading (≥12 wt.%). The dispersion of Pt, measured by the rate of cyclohexane dehydrogenation, increases with increasing of the pretreatment temperature of the support. It was shown that the kind of the support is very important for obtaining of catalysts resistant to carbon formation. The catalysts with high CeO2 loading (≥12 wt.%) showed the highest catalytic activity and stability in the reaction of partial oxidation of methane due to a higher Pt–CeO2 interface.