Browsing by Author "Pencheva D."

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    Experimental Study on the Components in Polyvalent ``ghost`` Salmonella Vaccine for Veterinary Use
    (2015-01-01) Pencheva D.; Velichkova E.; Sandarov D.; Cardoso A.; Mileva M.; Genova-Kalou P.; Bryaskova R.
    Development of ``ghost`` Salmonella vaccines, inactivated by using a hybrid nanomaterial based on silver nanoparticles (AgNps) stabilized via polyvinyl alcohol (PVA), is an innovative approach in vaccine production. For this purpose, a series of attempts to establish the components of the polyvalent ``ghost`` Salmonella vaccine and the most suitable methods for its preparation were performed. The following strains S. Enteritidis, S. Newport-Puerto Rico, and S. Typhimurium were chosen as appropriate candidates for their incorporation in order to create polyvalent Salmonella ``ghost`` vaccine for veterinary use.
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    Synthesis and comparative study on the antimicrobial activity of hybrid materials based on silver nanoparticles (AgNps) stabilized by polyvinylpyrrolidone (PVP)
    (2011-10-01) Bryaskova R.; Pencheva D.; Nikolov S.; Kantardjiev T.
    Hybrid materials based on polyvinylpyrrolidone (PVP) with silver nanoparticles (AgNps) were synthesized applying two different strategies based on thermal or chemical reduction of silver ions to silver nanoparticles using PVP as a stabilizer. The formation of spherical silver nanoparticles with diameter ranging from 9 to 16 nm was confirmed by TEM analysis. UV-vis and FTIR spectroscopy were also applied to confirm the successful formation of AgNps. The antibacterial activity of the synthesized AgNPs/PVP against etalon strains of three different groups of bacteria - Staphylococcus aureus (S. aureus; grampositive bacteria), Escherichia coli (E. coli; gram-negative bacteria), Pseudomonas aeruginosa (P. aeruginosa; nonferment gram-negative bacteria), as well as against spores of Bacillus subtilis (B. subtilis) was studied. AgNps/PVP were tested for the presence of fungicidal activity against different yeasts and mold such as Candida albicans, Candida krusei, Candida tropicalis, Candida glabrata, and Aspergillus brasiliensis. The hybrid materials showed a strong antimicrobial effect against the tested bacterial and fungal strains and therefore have potential applications in biotechnology and biomedical science. © Springer-Verlag 2011.
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    THERMAL PROPERTIES OF PVA/TEOS/AgNps THIN HYBRID FILMS AND THEIR FUNGICIDAL ACTIVITY TOWARDS REPRESENTATIVES OF GENUS CANDIDA
    (2022-01-01) Bryaskova R.; Pencheva D.
    The role of Candida infections in patients with weakened immune systems or hospitalized and catheterized patients is a worldwide problem with increasing importance. Due to the high fungal resistance to different type antifungals drugs, nowadays, the attention is paid towards novel hybrid coatings possessing strong antibacterial and fungicidal properties. The present article deals with the thermal behavior and fungicidal properties of novel hybrid materials based on polyvinyl alcohol (PVA)/tetraethyl orthosilicate (TEOS) films with included silver nanoparticles (AgNps) synthesized by sol-gel method. Thermal properties of the hybrid materials were investigated using TGA and DSC analysis. The fungicidal activity of the synthesized hybrid materials with included silver nanoparticles were tested onto control and clinical strains of genus Candida resistant to different antifungals. The antifungal activity of the synthesized materials was determined by Disk Diffusion Method (DDM) were the zone of inhibition of hybrid materials against control and clinical strains was monitoring.