The results of studies are considered in which the key physicochemical patterns of aqueous solutions of biologically active substances (BAS) of low concentrations prepared by the method of decimal dilutions and maintained under the conditions of natural and lowered levels of external physical fields have been established for the first time and described in terms of the self-organization of dispersed systems based on the study of a complex of experimental methods. A relationship between nonmonotonic coherent concentration dependences of the size, ζ-potential of the dispersed phase (nanoassociates), fluorescence intensity, UV absorption, specific electrical conductivity, surface tension, pH, and found by ecotoxicological tests biological properties of dilute solutions of practically important BAS (drugs, metabolic regulators, pesticides) was revealed using the developed algorithm. It has been shown that the consistency of nonmonotonic changes in the parameters of nanoassociates and properties of the systems in the range of low calculated concentrations makes it possible to predict bioeffects of the dilute BAS systems based on their physicochemical screening. The developed approach, which has predictive capabilities, and the established patterns contribute to the scientific foundation associated with the physicochemical substantiation of the nonmonotonic changes in the properties and elucidation of the mechanisms of the influence of aqueous dilute BAS systems and hypomagnetic conditions on the functioning of living organisms and form a methodological basis for future technologies in medicine, agriculture, protection of aquatic ecosystems and other areas of human activity.

New pharmacological compositions based on water-soluble pectin metal complexes PG-NaCaFe and PG-NaFeCoCu (PG is polygalacturonate) in weight ratios of 6: 1, 9: 1, and 12: 1 promising for pharmacology and medicine as drugs for the treatment of both iron deficiency and pernicious anemia are developed. According to the testing results on males of the Sprague Dawley rat line in vivo , the most pronounced increase in the number of erythrocytes and hematocrit is observed upon the introduction of the composition with the 9: 1 PG-NaCaFe to PG-NaFeCoCu weight ratio indicating the highest efficiency of this complex drug.

The results of studies in which the relationship of the self-organization, physicochemical properties, and bioeffects in dilute aqueous solutions of various biologically active substances sustained under natural and reduced levels of external physical fields (geomagnetic and low-frequency electromagnetic), as well as under exposure to ionizing radiation solutions studied by the complex of physicochemical methods, are considered. The established patterns can be used to create a scientific base related to the clarification of the mechanisms of the negative influence of hypomagnetic conditions on the functioning of living organisms necessary to ensure the normal operation of the ecosystem of spacecraft during flights.

A complex of physicochemical methods determined the relationship between the non-monotonic concentration dependencies of the size, ζ-potential of the dispersed phase, surface tension, fluorescence intensity (λ ex = 230 nm, λ em = 340 nm) of diluted aqueous systems of malic acid (MA) and their effect on the population of green algae Chlorella vulgaris and root growth of wheat Triticum vulgare . It was shown that the non-toxic, selective effect of MA systems on plant organisms occurs in the range of calculated concentrations, at which the greatest changes in the parameters of the dispersed phase, the surface tension, and the fluorescence intensity of the systems are observed.

As shown by fluorescence monitoring of dissolved organic matter, amino acid L-Trp can be present in natural water. The consequences of the presence of L-Trp at low concentrations in surface water systems are not yet established for hydrobionts. Studying the physicochemical patterns, as well as their relationships to the bioeffects of L-Trp solutions in the low concentration range, can provide new and important information regarding the unknown effects of L-Trp. The self-organization, physicochemical properties, fluorescence, UV absorption, and action of L-Trp solutions on Paramecium caudatum infusoria, Chlorella vulgaris algae were studied in the calculated concentrations range of 1 × 10−20–1 × 10−2 mol/L. The relationship between these phenomena was established using the certified procedures for monitoring the toxicity of natural water and wastewater. It was shown for the first time that aqueous solutions of L-Trp are dispersed systems in which the dispersed phase (nanoassociates) undergoes a rearrangement with dilution, accompanied by coherent changes in the nanoassociates’ parameters and the properties of systems. The non-monotonic concentration dependence of fluorescence intensity (λex at 225 nm, λem at 340 nm) is in good agreement with the data on the nanoassociates’ parameters, as well as with both the physicochemical properties of the systems and their bioassay results.

The formation of complexes of sodium polygalacturonate with the antimicrobial drug tetracycline was confirmed by UV spectroscopy, powder X-ray diffraction, and dynamic light scattering. The stoichiometry of the complexes with the maximum tetracycline content (6.68 wt.%) was determined. The morphological characteristics of the synthesized complexes were studied by scanning electron microscopy in comparison with the initial compounds.

It is found that temperature in the range of 25–60 °C affects the size and ζ-potential of dispersed phase domains, as well as specific conductance (χ), pH, UV absorption spectra and fluorescence of the succinic acid (SA)—water system with an SA concentration of 1 · 10−5 mol L−1. It was demonstrated that there is an interrelation between non-monotonic temperature dependences of the size and ζ-potential of domains, optical density (A260), fluorescence intensity (λex = 260 nm, λem = 425 nm), the χ and pH values of the system, which have extrema at 40 and 50 °C.

The relationship between non-monotonic concentration dependencies of the size of the dispersed phase (nanoassociates), physicochemical properties (specific electrical conductivity, pH), and fluorescence intensity (λex 225 nm, λem 340 nm) of a multi-component dispersed system based on herbicide N-(phosphonomethyl)glycine and its effect on the development of some hydrobionts and on the inhibition of Triticum vulgare wheat root growth in the range of calculated concentrations 1·10−19−1·10−3 g L−1 is established for the first time. The obtained results indicate that coherent changes in fluorescence intensity, physicochemical properties, and bioeffects are related to the rearrangement of nanoassociates which accompanies the dilution of the systems.

A variety of physicochemical methods were used to examine the self-organization, physicochemical, UV absorption, and fluorescent properties of diluted aqueous solutions (calculated concentrations from 1·10 −20 to 1·10 −2 M) of the membrane voltage-dependent potassium channels blocker 4-aminopyridine (4-AP). Using the dynamic light scattering method, it was shown that 4-AP solutions at concentrations in the range of 1·10 −20 –1·10 −6 M are dispersed systems in which domains and nanoassociates of hundreds of nm in size are formed upon dilution. An interrelation between the non-monotonic concentration dependencies of the size of the dispersed phase, the fluorescence intensity ( λ ex 225 nm, λ em 340 nm), specific electrical conductivity, and pH has been established. This allows us to predict the bioeffects of the 4-AP systems at low concentrations. The impact of these diluted aqueous systems on the electrical characteristics of identified neurons of Helix lucorum snails was studied. Incubation of neurons in the 4-AP systems for which the formation of domains and nanoassociates had been established lead to a nonmonotonic decrease of the resting potential by 7–13%. An analysis of the obtained results and published data allows for a conclusion that a consistent change in the nature and parameters of the dispersed phase, as well as the pH of the medium, apparently determines the nonmonotonic nature of the effect of the 4-AP systems in a 1·10 −20 –1·10 −6 M concentration range on the resting membrane potential of neurons. It was found that the pre-incubation of neurons in the 4-AP system with a concentration of 1·10 −12 M led to a 17.0% synergistic decrease in the membrane potential after a subsequent treatment with 1·10 −2 M 4-AP solution. This finding demonstrates a significant modifying effect of self-organized dispersed systems of 4-AP in low concentrations on the neurons’ sensitivity to 4-AP.

Self-organization, physicochemical properties (specific electrical conductivity, surface tension), UV absorption, and fluorescence of aqueous herbicide compositions based on N-(phosphonomethyl)glycine and plant growth regulator succinic acid (SA) were studied in a range of herbicide concentrations of 1·10−19−1·10−1 g L−1 at the constant concentrations of SA 1·10−3 g L−1 (series 1) and 1·10−13 g L−1 (series 2). Such compositions are used in agriculture for decreasing toxic effects on cultural plants and environment. A comparison of the nonmonotonic concentration dependences of the size and ξ-potential of the disperse phase, properties, and bioeffects of systems 1 and 2 revealed significant distinctions in these compositions in the ability of self-organization and surfactant properties, which can cause, as a whole, their substantial difference in the degree of harmful influence on aquatic life and higher plants. The influence of the compositions of series 1 is accompanied by a decrease in the harmful effect on the chosen biological test objects compared to the herbicide, and that of series 2 results in an almost complete elimination of the harmful effect against multicellular organisms (cladocerans and wheat roots) and an insignificant effect on unicellular aquatic life (infusoria and algae). The influence of the compositions of series 2 on aquatic life is related to the formation of a negatively charged disperse phase accompanied by an increase in the fluorescence intensity in a range of 300–360 nm (λexc = 225 nm).

The issue of protecting aquatic ecosystems from biologically active compounds (BACs) such as pesticides and pharmaceuticals detected in aquatic environments at low concentrations has become urgent. Presently, literature provides much information about BACs that at low concentrations cause significant damage to hydrobionts, but a physicochemical explanation for these phenomena has appeared only relatively recently. Experimental findings have shown that diluted aqueous solutions of BACs are self-organized disperse systems, whose disperse phase (nanoassociates) rearranges upon dilution, which is accompanied by nonmonotonous changes in the physicochemical and biological properties of the system. This work introduces the study of fluorescence and UV absorption of aqueous diluted systems of a biogenic succinic acid (SA), used as an antihypoxic and antioxidant pharmaceutical. It is shown for the first time that the fluorescence spectra (A ex at 225 nm) of SA systems are informative at the calculated concentrations range from 1.10(-17) to 1.10(-5) M. The nonmonotonous concentration dependence of fluorescence intensity (lambda(ex) at 225 nm, lambda(em) at 350 nm) is in good agreement with the data on nanoassociates' size, as well as with both the physicochemical properties of SA systems and their biotesting results, which were obtained using the certified procedures for monitoring the toxicity of natural waters and wastewater. The observed coherence between the fluorescence intensity of SA systems and the nanoassociates' size allows for the conclusion that it may be possible to consider fluorescence as a potential marker of self-organization and bioeffects of diluted aqueous BACs systems. (C) 2020 Elsevier B.V. All rights reserved.

Diclofenac sodium (DS) is a widely used nonsteroidal anti-inflammatory drug (NSAIDs). NSAIDs are poorly removed during standard wastewater treatment. The consequences of the presence of NSAIDs in rivers and lakes at 10(-11)-10(-8) mol/L are not yet established; therefore, ecotoxicologists have focused their efforts on studying the effect of low-concentration NSAIDs on fish and hydrobionts, and also on predicting the potential risks to humans. Literature provides some information about the bioeffects of some NSAID solutions in low concentrations but there is no physicochemical explanation for these phenomena. Studying the physicochemical patterns of DS solutions in the low range of concentrations and establishing an interconnection between the solutions' physicochemical properties and bioeffects can provide a conceptually new and important source of information regarding the unknown effects of DS. The physicochemical properties and action of DS solutions on Ceriodaphnia affinis cladocerans, Paramecium caudatum infusoria, Chlorella vulgaris unicellular green algae, as well as on the growth of the roots of Triticum vulgare wheat seeds, were studied in the calculated concentration range of 1 x 10(-3)-1 x 10(-18) mol/L. The relationship between these phenomena was established using the certified procedures for monitoring the toxicity of natural water and wastewater. It was shown for the first time that water solutions of DS are dispersed systems in which the dispersed phase undergoes a rearrangement with dilution, accompanied by changes in its size and properties, which affects the nonmonotonic dependences of the system's physicochemical properties and could cause nonmonotonic changes in action on hydrobionts in the low concentration range. (C) 2019 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.

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 .

The self-organization and physicochemical properties of aqueous solutions of the sodium salt of azosulfimate calix[4] arene (1) were studied in a wide range of concentrations 1.10(-10)-1.10(-1) M using a complex of methods. It has been found that the solutions of macrocycle 1 are in fact complex disperse systems, the nature of disperse phase in which changes with dilutions -from micelles (CMC = 2.5.10(-2) M) and premicellar aggregates (1.10(-2)-1.10(-3) M) of the size of 1 nm to supramolecular domains (1 .10(-3)-1. 10(-6) M) with sizes of tens and hundreds of nm. Jointly using the methods of dynamic light scattering and UV spectroscopy it was shown for the first time that the nonlinear character of the concentration dependence of the optical absorbance (A(360)) in the concentration range 1.10(-6)-1.5.10(-5) M is a result of the rearrangements of supramolecular domains of 1, accompanied by the transition from bi- to monomodal pattern of particles' size distribution, as well as by non-monotonic change in their size and zeta-potential. It was established that molecules of 1 are not capable of photoisomerization of the azobenzene group, which may be due to steric hindrances to the process of isomerization of closely located azoarylsulfonate groups located on one side of the plane of macrocycle 1.

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.

It has been shown for the first time that aqueous solutions of quaternary phosphonium salts (cetyltributylphosphonium bromide, cetyltriphenylphosphonium bromide) in the range of 1x10(-2)-1x10(-18)mol/L are disperse systems. The nature of the disperse phase changes as the solution is diluted, starting from micelles (1x10(-4)-1x10(-2)mol/L), translating into molecule-water domains (1x10(-6)-1x10(-4)mol/L) and nanoassociates (1x10(-18)-1x10(-6)mol/L). The effect that these compounds' solutions have on the growth and development of hydrobionts (infusoria Paramecium caudatum and single-celled algae Chlorella vulgaris) in the low concentrations range has been studied for the first time. It was found that at a concentration less than 1x10(-6)mol/L the nonmonotonic concentration dependences of the physicochemical properties and bioeffects of the systems are related to the formation and rearrangement of nanoassociates. [GRAPHICS] .

A set of physicochemical methods was used to establish that aqueous solutions of chloracetophos fungicide and bactericide (1) in the range of calculated concentrations from 1•10–18 to 1•10–4 mol L–1 are disperse systems in which a dispersed phase hundreds of nanometers in size is formed above and below a threshold concentration of 1•10–9 mol L–1. Upon dilution disperse systems 1 are capable of non-monotonic changing the physicochemical properties and changing the toxicity profile (inhibition–stimulation) when influencing the growth and development of unicellular algae Chlorella vulgaris. The formation of domains and nanoassociates is accompanied by the appearance in the UV spectrum of an absorption band at 210–300 nm with a maximum at ~220 nm (A220). The interrelated concentration dependences of A220, the size of the dispersed phase, and electrical conductivity indicates that the observed spectral features of systems 1 are caused by the properties of the domains and nanoassociates.

It has been shown for the first time that aqueous solutions of metaphos pesticide (1×10–4–1×10–17 mol/L) are disperse systems, the disperse phase undergoing rearrangement upon dilution. The relationship between nonmonotonic concentration dependences of the nanoassociate size, physico-chemical properties of the systems, and their action on higher plants and hydrocoles has been found.

Using a complex of physicochemical methods it has been shown for the first time that the diluted solutions (10-11-10-3.) of dodecyl derivative of p-sulfonatocalix[6] arene are disperse systems, where the role of a disperse phase is played by the supramolecular structures of different nature - micelles (above 6.10(-4).), domains (1.10(-4)-1.10(-7).) and nanoassociates (1.10(-9)-1.10(-8).). The disperse phase's parameters change nonmonotonically as systems dilution, what results in the decrease of surface tension at concentrations lower than the critical micelle concentration and determines the differences in systems' behaviour at various temperatures (15-60 degrees C) and hold up times (after 8 months).

It is shown for the first time using a complex of physicochemical methods (dynamic and electrophoretic light scattering, conductometry, pH-metry) that below a threshold concentration of 1.0•10 –7 mol L –1 the disperse phase of the aqueous systems based on moss peptide PpCLE2 undergoes the domain—nanoassociate rearrangement, which affects the nonmonotonic concentration dependences of the specific electrical conductivity and pH and can result in a multidirectional profile of the dependence of the growth of the primary and lateral roots of the Arabidopsis thaliana seed plant in the range of calculated concentrations from 1.0•10 –6 to 1.0•10 –12 mol L –1 .