Vladimir B. Tsvetkov

Learn More
New natural and chemically modified DNA aptamers that inhibit HIV-1 activity at submicromolar concentrations (presumably via preventing viral entry into target cells) are reported. The new DNA aptamers were developed based on known intramolecular G-quadruplexes (G4s) that were functionally unrelated to HIV inhibition [the thrombin-binding aptamer and the(More)
Cationic porphyrin-based compounds capable of interacting with DNA are currently under extensive investigation as prospective anticancer and anti-infective drugs. One of the approaches to enhancing the DNA-binding affinity of these ligands is chemical modification of functional groups of the porphyrin macrocycle. We analyzed the interaction with DNA of(More)
A series of DNA aptamers bearing triazole internucleotide linkages that bind to thrombin was synthesized. The novel aptamers are structurally analogous to the well-known thrombin-inhibiting G-quadruplexes TBA15 and TBA31. The secondary structure stability, binding affinity for thrombin and anticoagulant effects of the triazole-modified aptamers were(More)
Nowadays, terbium gallium garnet (TGG) single crystals are most popular media for compact Faraday rotators and Faraday isolators for visible and near infrared range. Their main advantages are high Verdet constant, high optical quality and low absorption. The main technique of TGG single crystals growing is still Czochralski method despite efforts directed(More)
The definition of DNA and RNA G-quadruplexes (G4s) has recently been broadened to include structures with certain defects: bulges, G-vacancies or mismatches. Despite the striking progress in computational methods for assessing G4 folding propensity, predicting G4s with defects remains problematic, reflecting the enhanced sequential diversity of these(More)
The only recognized virulence factor of enterotoxigenic Bacteroides fragilis (ETBF) that accompanies bloodstream infections is the zinc-dependent non-lethal metalloprotease B. fragilis toxin (BFT). The isolated toxin stimulates intestinal secretion, resulting in epithelial damage and necrosis. Numerous publications have focused on the interrelation of BFT(More)
Broadband NIR photoluminescence (from 1000 to 2500 nm) was observed from partially reduced AlCl₃/ZnCl₂/BiCl₃ glass, containing subvalent bismuth species. The luminescence consists of three bands, assigned to Bi⁺ , Bi₂⁴⁺, and Bi₅³⁺ ions. The physical and optical characteristics of these centers and possible contribution to NIR luminescence from bismuth-doped(More)
At present long wavelength limit for supercontinuum generation in the silica based fibers was shown [1, 2]. Also one of the interesting problems is to obtain the high spectral power density. One of the ways to get it is using optical fiber amplifiers as a media for supercontinuum generation. Yb-doped fiber amplifier was used for supercontinuum generation(More)
Anthraquinones and their analogues, in particular heteroarene-fused anthracendiones, are prospective scaffolds for new compounds with improved antitumor characteristics. We herein report the use of a 'scaffold hopping' approach for the replacement of the core structure in the previously discovered hit compound naphtho[2,3-f]indole-5,10-dione 2 with an(More)
Terbium garnet single crystals (terbium gallium garnet, TGG, and terbium-scandium gallium garnet, TSAG) combine relatively high Verdet constant, low absorption coefficient, high thermal conductivity and high optical quality. The combination of properties leads to TGG being the most popular magneto-optic material at high-power applications for creation(More)