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Vol 467, No 2 (2016)
- Year: 2016
- Articles: 5
- URL: https://journals.rcsi.science/0012-5016/issue/view/9195
Physical Chemistry
Synthesis and physicochemical properties of antianemic iron and calcium complexes with sodium polygalacturonate
Abstract
New stable water-soluble metal complexes of citrus pectin (sodium polygalacturonate, PG-Na) with biogenic microelements (Ca and Fe) that we synthesized were characterized by infrared spectroscopy, dynamic light scattering, and atomic force microscopy. The temperature dependence of the mass of PG-Na, PG-NaFe, and PG-NaFeCa samples was studied by simultaneous thermal analysis. Water was found to be the major component of the gas phase in the first stage of mass loss of PG-NaFe and PG-NaFeCa, while the second stage involves decarboxylation and decomposition. The stimulating action of PG-NaFe and PG-NaFeCa on hematopoiesis in outbred rats during growing period, manifested as more than 10% increase in the hemoglobin concentration, was demonstrated.
45-48
High-temperature heat capacity and thermodynamic properties of Pb4V2O9 and Pb8V2O13
Abstract
The molar heat capacity of Pb4V2O9 and Pb8V2O13 in the temperature range 350–1000 K was measured by differential scanning calorimetry. It was determined that the plot Cp = f(T) for Pb8V2O13 has an extremum within the range 416–516 K, which is due to a phase transition. A correlation was found between the heat capacity and composition of oxides in the PbO–V2O5 system. The data obtained allowed one to predict the specific heat capacity value for Pb(VO3)2.
49-52
Hexagonal → cholesteric phase transition of DNA molecules in liquid-crystalline dispersion particles
Abstract
To assess the character of packing of double-stranded (ds) DNA molecules in liquid-crystalline dispersion particles formed by phase exclusion of DNA molecules from aqueous salt solutions of poly(ethylene glycol), the circular dichroism spectra of these dispersions at different temperatures have been compared. It has been shown for the first time that heating dispersion particles with the hexagonal packing of ds-DNA molecules is accompanied by the hexagonal → cholesteric phase transition. This result can be described using the notion of quasi-nematic layers composed of orientationally ordered adjacent ds-DNA molecules in the structure of dispersion particles; these layers can be packed in two ways dictating their hexagonal or cholesteric spatial structure.
53-55
Mechanism of the formation of photosensitive nanostructured TiO2 with low content of CdS nanoparticles
Abstract
A method for synthesizing a CdS/TiO2 composite material, active in the visible region, was described. The CdS/TiO2 composite was obtained by the sol–gel synthesis of nanostructured TiO2 in a medium of a stable colloidal solution of CdS nanoparticles. The TiO2 matrix produced by the sol–gel process is amorphous and contains a nanocrystalline anatase phase, the content of which depends on the Ti(OBu)4 hydrolysis rate. The content of CdS nanoparticles forming in the colloidal solution and participating in the TiO2 matrix sensitization is determined by the initial CdS: Ti(OBu)4 ratio. Although the content of CdS nanoparticles in the composite is low (no more than 3 wt %), the composite demonstrates catalytic activity in the visible region, thus proving the possibility of reducing the content of toxic CdS nanoparticles in the TiO2 matrix without decreasing the photosensitivity of the CdS/TiO2 composite.
56-59
Monoethanolamine clusters as prototypes of the inherent structure elements of the liquid
Abstract
Possible motives of the inherent structure of liquid monoethanolamine determined by the peculiarities of the hydrogen-bond network in the absence of thermal perturbations have been analyzed for the first time based on the results of quantum-chemical calculations of molecular clusters of monoethanolamine, which is a model substance of biological systems and a cryoprotective agent in cryobiology.
60-62