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1.
Kolev TM Yancheva DY Stamboliyska BA 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2003,59(8):1805-1813
The FTIR spectra of pyridinium-betaine of squaric acid in 4000-100 cm(-1) frequency region in solid state were measured. In addition, the structure and harmonic vibrational frequencies of this molecule were theoretically evaluated using restricted Hartree-Fock and B3LYP density functional methods. The computed vibrational frequencies are used to determine the types of molecular motions associated with each of the experimental bands observed. Comparison with the experimental spectra provides important information about the ability of these computational methods to describe the vibrational modes in these highly polar strained ring compounds. 相似文献
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Yancheva E Paneva D Danchev D Mespouille L Dubois P Manolova N Rashkov I 《Macromolecular bioscience》2007,7(7):940-954
Polyelectrolyte complexes (PECs) between (quaternized) poly[2-(dimethylamino)ethyl methacrylate] (PDMAEMA) and (crosslinked) N-carboxyethylchitosan (CECh) or poly(2-acrylamido-2-methylpropane sodium sulfonate) (PAMPSNa) were prepared and characterized in terms of their stability, equilibrium water content, and surface morphology. The evaluation of the behavior of the studied PECs in contact with blood revealed that the (crosslinked) CECh/(quaternized) PDMAEMA complexes had lost the inherent PDMAEMA cytotoxicity but still preserved haemostatic activity. In contrast, the complex formation between (quaternized) PDMAEMA and PAMPSNa allowed the preparation of materials with improved blood compatibility. 相似文献
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E Cherneva V Pavlovic A Smelcerovic D Yancheva 《Molecules (Basel, Switzerland)》2012,17(9):10258-10266
Camphor and borneol are wildly distributed in the essential oils of medicinal plants from various parts of the World. Our study has been carried out to evaluate the effect of these two bicyclic monoterpenes on rat thymocytes. Camphor and borneol at concentrations of 0.5 and 5 μg/mL did not induce significant toxicity on the immune system cells, while a significant increase of thymocyte viability was detected when cells were incubated with 50 μg/mL of camphor. A significant increase of cell viability was similarly detected when thymocytes were cultivated with borneol at concentrations of 0.5 and 5 μg/mL. The role of camphor and borneol in reactive oxygen species (ROS) production and mitochondrial membrane potential (MMP) disturbances in rat thymocytes as well as their potential mechanism(s) of action were also discussed. 相似文献
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Guncheva Maya Todinova Svetla Yancheva Denitsa Idakieva Krassimira 《Journal of Thermal Analysis and Calorimetry》2020,142(5):1903-1909
Journal of Thermal Analysis and Calorimetry - Two oxygen-transporting proteins known for their immunostimulating and anticancer properties, namely hemocyanin from Helix lucorum (HlH) and hemocyanin... 相似文献
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Maya Guncheva Krassimira Idakieva Svetla Todinova Denitsa Yancheva Tsvetelina Paunova-Krasteva Paula Ossowicz Ewa Janus 《Molecules (Basel, Switzerland)》2021,26(6)
Novel biocompatible compounds that stabilize proteins in solution are in demand for biomedical and/or biotechnological applications. Here, we evaluated the effect of six ionic liquids, containing mono- or dicholinium [Chol]1or2 cation and anions of charged amino acids such as lysine [Lys], arginine [Arg], aspartic acid [Asp], or glutamic acid [Glu], on the structure, thermal, and storage stability of the Rapana thomasiana hemocyanin (RtH). RtH is a protein with huge biomedicinal potential due to its therapeutic, drug carrier, and adjuvant properties. Overall, the ionic liquids (ILs) induce changes in the secondary structure of RtH. However, the structure near the Cu-active site seems unaltered and the oxygen-binding capacity of the protein is preserved. The ILs showed weak antibacterial activity when tested against three Gram-negative and three Gram-positive bacterial strains. On the contrary, [Chol][Arg] and [Chol][Lys] exhibited high anti-biofilm activity against E. coli 25213 and S. aureus 29213 strains. In addition, the two ILs were able to protect RtH from chemical and microbiological degradation. Maintained or enhanced thermal stability of RtH was observed in the presence of all ILs tested, except for RtH-[Chol]2[Glu]. 相似文献
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Anelia Mavrova Stephan Dimov Inna Sulikovska Denitsa Yancheva Ivan Iliev Iana Tsoneva Galya Staneva Biliana Nikolova 《Molecules (Basel, Switzerland)》2022,27(10)
Novel 4-amino-thieno[2,3-d]pyrimidine-6-carboxylates substituted at the second position were prepared by cyclocondensation of 2-amino-3-cyano-thiophene and aryl nitriles in an acidic medium. The design of the target compounds was based on structural optimization. The derivatives thus obtained were tested in vitro against human and mouse cell lines. The examination of the compound effects on BLAB 3T3 and MFC-10A cells showed that they are safe, making them suitable for subsequent experiments to establish their antitumor activity. The photoirritancy factor of the compounds was calculated. Using the MTT test, the antiproliferative activity to MCF-10A, MCF-7 and MDA-MB-231 cell lines was estimated. The best antiproliferative effect in respect to the MCF-7 cell line revealed compound 2 with IC50 4.3 ± 0.11 µg/mL (0.013 µM). The highest selective index with respect to MCF-7 cells was shown by compound 3 (SI = 19.3), and to MDA-MB-231 cells by compound 2 (SI = 3.7). Based on energy analysis, the most stable conformers were selected and optimized by means of density functional theory (DFT). Ligand efficiency, ligand lipophilicity efficiency and the physicochemical parameters of the target 4-amino-thienopyrimidines were determined. The data obtained indicated that the lead compound among the tested substances is compound 2. 相似文献
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Guncheva Maya Todinova Svetla Yancheva Denitsa Raynova Yuliana Idakieva Krassimira 《Journal of Thermal Analysis and Calorimetry》2019,138(4):2715-2720
Journal of Thermal Analysis and Calorimetry - This is the first report on the conjugation of a hemocyanin from Rapana thomasiana (RtH) with ferulic acid, which itself exhibits an immunostimulatory... 相似文献
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Kolev TM Yancheva DY Stamboliyska BA 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2003,59(14):3325-3335
The FTIR spectra (4000-100 cm(-1)) and Raman spectra (3500-30 cm(-1)) of 2-[5,5-dimethyl-3-(2-phenyl-vinil)-cyclohex-2-enylidene]-malononitrile in solid state were measured. In addition, the structure and harmonic vibrational frequencies of this molecule were theoretically evaluated using B3LYP density functional methods. The computed vibrational frequencies are used to determine the types of molecular motions associated with each of the experimental bands observed. Bond length alternation (BLA) was established. Comparison with the experimental spectra provides important information about the ability of this computational method to describe the vibrational modes in this type of "push-pull" systems with potential non-linear optical applications. 相似文献
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