129 research outputs found
General features of the energetics of complex formation between ligand and nucleic acids
The analysis of the energy contributions of various physical factors to the complex formation between biologically active compounds and nucleic acids in aqueous solution was performed. A comparison of the energy parameters was made for ligand-ligand, intercalator-DNA, MGB-DNA and ligand-RNA groups. It was shown that the energetics of these reactions is of compensatory nature. Physical factors exerting the most pronounced influence on the energy parameters were identified. Correlation of the energy contributions to MGB-DNA complex formation and its biological effect was foun
Binding polynomial in molecular self-assembly
In the present work the concept of a binding polynomial is revisited for the most widely used case of self-assembly of identical molecular units and results in the re-construction of a link to the grand partition function of such a system. It is found that if the self-assembly process is not pronounced (i.e., the product of the equilibrium constant and the monomer concentration is close to zero), the binding polynomial has the meaning of a molecular partition function that is given by the summation over energy levels of any molecule in the system. In other cases the concept of a binding polynomial may be misleadin
Antitumor effects and hematotoxicity of С60-Cis-Pt nanocomplex in mice with lewis lung carcinoma
To estimate the antitumor effects of С60-Cis-Pt nanocomplex in Lewis lung carcinoma (LLC) and analyze hematological toxicity in tumor-bearing mic
Dimerization energetics of DNA minor groove binders
The energy analysis of a dimerization in aqueous solutions of seven biologically active lexitropsins, which are different by structure, was carried out with the use of the molecular simulation method. The main stabilization of dimers was shown to take place owing to hydrophobic and intermolecular van der Waals interactions. The latter are mainly associated with energyfavorable contacts between the aromatic rings of molecules and their peptide groups. Despite the significant dipole moments of the molecules concerned, the electrostatic interactions are relatively weak and destabilize the complexes because of the unfavorable relative arrangement of molecular dipoles. Entropic factors and the dehydration were shown to also hinder the dimerizatio
Levy stable noise induced transitions: stochastic resonance, resonant activation and dynamic hysteresis
A standard approach to analysis of noise-induced effects in stochastic
dynamics assumes a Gaussian character of the noise term describing interaction
of the analyzed system with its complex surroundings. An additional assumption
about the existence of timescale separation between the dynamics of the
measured observable and the typical timescale of the noise allows external
fluctuations to be modeled as temporally uncorrelated and therefore white.
However, in many natural phenomena the assumptions concerning the
abovementioned properties of "Gaussianity" and "whiteness" of the noise can be
violated. In this context, in contrast to the spatiotemporal coupling
characterizing general forms of non-Markovian or semi-Markovian L\'evy walks,
so called L\'evy flights correspond to the class of Markov processes which
still can be interpreted as white, but distributed according to a more general,
infinitely divisible, stable and non-Gaussian law. L\'evy noise-driven
non-equilibrium systems are known to manifest interesting physical properties
and have been addressed in various scenarios of physical transport exhibiting a
superdiffusive behavior. Here we present a brief overview of our recent
investigations aimed to understand features of stochastic dynamics under the
influence of L\'evy white noise perturbations. We find that the archetypal
phenomena of noise-induced ordering are robust and can be detected also in
systems driven by non-Gaussian, heavy-tailed fluctuations with infinite
variance.Comment: 7 pages, 8 figure
Comparative analysis of the antineoplastic activity of C60 fullerene with 5-fluorouracil and pyrrole derivative in vivo
The antitumor activity of pristine C60 fullerene aqueous solution (C60FAS) compared to 5-fluorouracil (5-FU) and pyrrole derivative 1-(4-Cl-benzyl)-3-Cl-4-(CF3-fenylamino)-1H-pyrrol-2.5-dione (MI-1) cytostatic drugs was investigated and analyzed in detail using the model of colorectal cancer induced by 1.2-dimethylhydrazine (DMH) in rat
- …