A relationship between the nonmonotonic concentration dependences of the size of the dispersed phase (nanoassociates), physicochemical properties (electric conductivity, pH, redox potential), and ...fertility of hydrobionts under the action of solutions of citric (CA) and succinic (SA) acids in low concentrations was established. Solutions of CA stimulate the fertility of
Paramecium caudatum
infusoria and
Chlorella vulgaris
algae in a wide range of formation of domains and nanoassociates (1•10
–13
–1•10
–5
mol L
–1
), whereas solutions of SA exert almost no effect on the fertility and slightly inhibit it only in a range of nanoassociate formation at the calculated concentrations from 1•10
–17
to 1•10
–14
mol L
–1
.
Using a combination of physicochemical methods (dynamic and electrophoretic light scattering (DLS and ELS, respectively), nanoparticle tracking analysis, atomic force and transmission electron ...microscopy (AFM and TEM, respectively), UV spectroscopy, conductometry, pH-metry, dielcometry), it was found that dilute solutions of a multicomponent drug immunomodulator polyoxidonium (PO) are nanoheterogeneous disperse systems, with their disperse phase undergoing considerable restructurings when diluting the solution in the range of calculated concentrations from 1∙10–1 to 1∙10–16 mg mL–1, which is reflected in the non-monotonous concentration dependencies of specific electroconductivity, dielectric permittivity, and pH of the solutions. Using ELS, AFM, TEM, and UV spectroscopy methods, it was found that the disperse phase with a size of hundreds of nanometers which forms at concentrations of ≤1∙10
–5
mg mL
–1
, contains organized water structures substantiating the negative values of ζ-potential, which vary non-monotonously from–5 to–16 mV. Radioprotective properties of dilute solutions of PO (1∙10
–1
and 1∙10
–9
mg mL
–1
) were demonstrated for the first time when exposing the test mutant bacterial strain
Salmonella typhimurium TA 100
(Ames test) to X-ray radiation in a dose of 7.50 mGy used for medical diagnostics.
The relationship between rearrangement of the dispersed phase inducing considerable changes in the pH and nonmonotonic concentration dependences of membrane effects in aqueous systems of the ...endogenous regulatory peptide, thyroliberin (thyrotropin-releasing hormone), in 10
–3
–10
–16
mol/L concentration range was demonstrated for the first time. The membrane structure modification in the 10
–13
–10
–16
mol/L range was found to be due to accumulation of nanoassociates, while the oppositely directed pronounced structural changes in the 10
–6
–10
–12
mol/L range may be associated with the coexistence and rearrangement of dispersed phases of various nature (domains and associates) whose action on membrane lipid components is regulated in this concentration range by the correlated changes in the dispersed phase parameters and pH.
The formation of stable complexes of pectin polysaccharides with 1-(2-hydroxyethyl)-4,6- dimethyl-1,2-dihydropyrimidin-2-one (Xymedon drug) was shown by UV and IR spectro scopy, dynamic light ...scattering, and polarimetry. The stoichiometry of the complexes was determined, and their synthesis conditions were optimized. Specific features of the thermal decomposition of pectin and synthesized complexes with Xymedon were studied by the TG/DSC method. The results obtained allow one to substantially extend ranges of using Xymedon in medicine.
Two amphiphilic butadienyl dyes
1 and
2 form stable monolayers at the air/water interface in the presence of various salts. Dye
1 consists of the basic amphiphilic butadienyl chromophore. In dye
2, ...the dimethoxybenzene part of dye
1 is substituted by benzodithia-15-crown-5. The monolayers have been characterized by surface pressure-area and surface potential-area isotherms as well as Brewster angle microscopy and reflection spectroscopy. In contrast to dye
1, dye
2 interacts specifically with Hg
2+ and Ag
+ cations forming complexes
. No complex formation was observed with alkali and earth alkali metal ions. The nature of the anion (Cl
− or ClO
4
−) influences the monolayer behaviour of both dyes. At the air/water interface, besides monomers of the dyes, two types of associates are coexisting in the pure dye monolayers on aqueous salt solutions, attributed to dimers and aggregates, respectively. Their equilibria depend on the nature of both cations and anions in the subphase, as in the case of dye
2, or only anions, as in the case of dye
1. The dimers may be organized as head-to-tail dimers with the intermolecular distances 0.38 and 0.45
nm for dye
1 and dye
2, respectively. According to the extended dipole model, we propose formation of aggregates in which the chromophores are parallel to each other with the same intermolecular distances as in the dimers, and the centers of their transition moments shifted by 0.95
nm (dye
1) and 1.2
nm (dye
2).
The structures, electrochemical properties, enantiomeric separation of ferrocenyl-(alkyl)pyrimidines and ferrocenyl(ethyl)adenine and their effects on the DNA synthesis in tumor cells were studied. ...Enantiomeric mixtures were separated by HPLC on modified cellulose as the chiral selector. The electrochemical properties of compounds were studied by cyclic voltammetry. All compounds have reversible single-electron redox transition in the region of 0.52–0.60 V, which belongs to ferrocene—ferrocenium with a positive shift compared to ferrocene (0.52 V). The molecular structure of 1-
N
-(ferrocenylbenzyl)-5-iodocytosine was studied by X-ray diffraction. 1-
N
-(Ferrocenylethyl)adenine was studied for ability to inhibit the DNA synthesis in the human ovarian cancer cell culture by the
3
H-thymidine test.
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