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1.
Nina Georgieva Kostova Elka Kraleva Alla A. Spojakina Erika Godocikova Peter Balaz 《Journal of Materials Science》2007,42(10):3321-3325
The Al-MCM-41 has been used as support to prepare Mo-containing catalysts. The 12- molybdophosphoric heteropoly acid (HPMo)
is used as initial compound. The catalysts are synthesized by two different methods: incipient impregnation with aqueous solution
of the acid and mechanochemical synthesis. The samples were tested in the reaction of the thiophene hydrodesulfurization after
activation with mixture H2 + H2S. The effect of the preparation method of the catalysts on their physicochemical and catalytic properties has been studied.
A partial destruction of the loaded compound is observed in mechanochemically treated sample whereas the aggregates are formed
from the particles of different size in the impregnated sample. The specific surface area of the sample prepared by mechanical–chemical
treatment decreases 2–3 times, while the total pore volume is about four times lower. The HDS activity is higher on the impregnated
sample than on the mechanochemically treated one. 相似文献
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New complexes of coumarin-3-carboxylic acid (HCCA) with Ho(III) and Pr(III) were synthesized and their structures and spectral properties were investigated by elemental analysis, IR, Raman and NMR measurements. According to the experimental data the complexes' formula and geometries were suggested. Vibrational frequencies, IR intensities and Raman activities as well as 1H NMR chemical shifts of HCCA and its Ho(III) and Pr(III) complexes were presented. The comparative experimental vibrational and NMR analyses of both the ligand and the Ln(III) complexes predicted the bidentate binding to Ho(III) and Pr(III) through the deprotonated carboxylic oxygen and the carbonylic oxygen of the ligand. The cytotoxic/cytostatic properties of the ligand and the newly synthesized complexes of coumarin-3-carboxylic acid with Ho(III) and Pr(III) were tested by MTT reduction assay against two mouse tumor cell lines: melanoma B16 and fibrosarcoma L929. They were also tested for cytotoxicity against normal mouse peritoneal macrophages. The proliferation inhibitory effect of the complexes compared to that of the ligand proved their cytotoxic/cytostatic properties against both the tumor cell lines. In addition, the complexes were less cytotoxic against normal mouse macrophages and were able to modulate NO release by activated macrophages. The obtained results were in accordance with our previously published data concerning the activity of lanthanide(III) complexes with other coumarin derivatives. 相似文献
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Dimitrov R Timeva T Kyurkchiev D Stamenova M Shterev A Kostova P Zlatkov V Kehayov I Kyurkchiev S 《Reproduction (Cambridge, England)》2008,135(4):551-558
Human endometrium is an object of extensive restructuring and remodeling during the female reproductive life and it is quite tempting to assume that these periodic changes happen with the participation of cells that should have the basic characteristics of multipotent cells. The aim of this study was to search for the presence of cells with plastic adherence, clonogenicity, and differentiation in human endometrium. To this end, human endometrial stromal cells were cultured in vitro for more than 15 passages. Flow cytometry analysis of the cultured cells showed that they were positive for CD29, CD73 and CD90, which are considered to be the markers of cells with mesenchymal origin. The cells were negative for the hematopoietic cell markers (CD45, CD34, CD14, CD3, CD19, CD16/56, and HLA-DR). Further, it was shown that the cultured cells had 15% clonogenic efficiency and could be induced to differentiate into adipogenic cells containing typical lipid-rich vacuoles. These results demonstrate that the human endometrium contains a low number of cells with the characteristics of endometrial stromal stem/progenitor cells, which seem to belong to the family of the mesenchymal stem cells. It can be speculated that these cells are engaged into the monthly restructuring and remodeling of human endometrium. 相似文献
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Abstract and Key Results
相似文献
▪ | Subsidiary managers are faced with complex managerial roles involving both the interests of the multinational corporation (MNC) and the subsidiary. We suggest complex roles are best fulfilled when managers develop dual organizational identification towards both entities. |
▪ | Based on a conceptualization of dual organizational identification in terms of relative magnitude, we test the effect of dual identification on subsidiary manager roles and role conflict. |
▪ | Results indicate that high identification with both entities is associated with high role fulfillment and that similarity in organizational identities directly affects role conflict. |
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Fouzar Samia Kostova Irena Eftimov Tinko Benmounah Abdelbaki Ouchabane Mohammed Lakhssassi Ahmed 《Journal of Materials Science: Materials in Electronics》2022,33(26):20962-20980
Journal of Materials Science: Materials in Electronics - In this paper, we study the phosphorescence rise and decay time responses of Eu2+- and Dy3+-doped strontium aluminates prepared by different... 相似文献
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New complexes of coumarin-3-carboxylic acid(HCCA) with Ho(Ⅲ) and Pr(Ⅲ) were synthesized and their structures and spectral properties were investigated by elemental analysis,IR,Raman and NMR measurements.According to the experimental data the complexes’ formula and geometries were suggested.Vibrational frequencies,IR intensities and Raman activities as well as 1H NMR chemical shifts of HCCA and its Ho(Ⅲ) and Pr(Ⅲ) complexes were presented.The comparative experimental vibrational and NMR analyses of both the ligand and the Ln(Ⅲ) complexes predicted the bidentate binding to Ho(Ⅲ) and Pr(Ⅲ) through the deprotonated carboxylic oxygen and the carbonylic oxygen of the ligand.The cytotoxic/cytostatic properties of the ligand and the newly synthesized complexes of coumarin-3-carboxylic acid with Ho(Ⅲ) and Pr(Ⅲ) were tested by MTT reduction assay against two mouse tumor cell lines:melanoma B16 and fibrosarcoma L929.They were also tested for cytotoxicity against normal mouse peritoneal macrophages.The proliferation inhibitory effect of the complexes compared to that of the ligand proved their cytotoxic/cytostatic properties against both the tumor cell lines.In addition,the complexes were less cytotoxic against normal mouse macrophages and were able to modulate NO release by activated macrophages.The obtained results were in accordance with our previously published data concerning the activity of lanthanide(Ⅲ) complexes with other coumarin derivatives. 相似文献
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Matej Baláž Peter Baláž Georgi Tjuliev Anton Zubrík María Jesús Sayagués Anna Zorkovská Nina Kostova 《Journal of Materials Science》2013,48(6):2424-2432
Cystine-capped CdSe@ZnS nanocomposites were synthesized mechanochemically with the aim to prepare a material which could be used in medicine for biosensing applications. Although synthesized CdSe@ZnS nanocomposites were capped with l-cysteine, cystine was formed from l-cysteine during the milling process. It was proven that water plays the key role in this oxidative transformation. The novel material was characterized by the complex of physico-chemical methods (FTIR, XPS, SEM, EDX, surface area measurements) and CHNS analysis. The leakage of Cd2+ and Zn2+ ions into physiological solution was also studied. 相似文献
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A. A. Spojakina N. G. Kostova B. Sow M. W. Stamenova K. Jiratova 《Catalysis Today》2001,65(2-4):315-321
Surface properties of supported MoV heteropoly compounds and their activities in hydrodesulfurization of thiophene and oxidation of ethanol were studied. Vanadium incorporated into the phosphomolybdic acid anion increased extent of oxidative dehydrogenation of ethanol to acetaldehyde, whereas the catalyst with (VO)2+ increased complete ethanol oxidation to CO2. The catalysts with (VO)2+ or one V atom in the anion showed an increase in HDS activity. Vanadium in anion of phosphomolybdic acid also increased hydrogenation ability. Acidic sites of medium strength were proved to be the most suitable for ethanol oxidation. Such explicit dependence of thiophene hydrodesulfurization on any type of acidic sites was not confirmed. Activity order of supported MoV heteropoly compounds in HDS of thiophene correlated well with the amount of hydrogen consumed during TPR. 相似文献