Study of biocolloids by radiospectroscopic methods (interactions of phospholipid vesicles with polynucleotides)

Radiospectroscopic methods were used to study the interactions of phospholipid vesicles with polyadenylic and polyuridylic acids in the presence of bivalent cations of magnesium. The possibility of complex formation between vesicles and poly-A:U duplex as well as the role of magnesium ions in this process were demonstrated. Magnesium cations form bridges between phosphate surface groups of bilayer and the residues of phosphoric acid of the polynucleotides. The structural changes in biocolloid particles during the formation of triple complexes were observed. © 1997 Akadémiai Kiado,

Study of biocolloids by radiospectroscopic methods (interactions of phospholipid vesicles with polynucleotides)

Radiospectroscopic methods were used to study the interactions of phospholipid vesicles with polyadenylic and polyuridylic acids in the presence of bivalent cations of magnesium. The possibility of complex formation between vesicles and poly-A:U duplex as well as the role of magnesium ions in this process were demonstrated. Magnesium cations form bridges between phosphate surface groups of bilayer and the residues of phosphoric acid of the polynucleotides. The structural changes in biocolloid particles during the formation of triple complexes were observed. © 1997 Akadémiai Kiado,

NMR method in the study of the interfacial adsorption layer of gelatin

The interfacial adsorption layers of gelatin at a benzene/gelatin solution in D2O interface were studied by NMR using the oil-in-water emulsions prepared by ultrasonic dispersion in conditions where the gelatin macromolecules are in a coiled conformation. The intensities of the proton signals from the gelatin decreased and the NMR spectral lines broadened upon the formation of interfacial adsorption layers of gelatin (T > 313 K). The result is similar to that of collagen-like helices and gels of gelatin and shows that the fraction of mobile gelatin segments in interfacial adsorption layers decreases virtually to zero. The presence of two different signals in the NMR spectrum suggests that benzene is solubilized by gelatin macromolecules and constitutes one component of the interfacial adsorption layer of gelatin

NMR method in the study of the interfacial adsorption layer of gelatin

The interfacial adsorption layers of gelatin at a benzene/gelatin solution in D2O interface were studied by NMR using the oil-in-water emulsions prepared by ultrasonic dispersion in conditions where the gelatin macromolecules are in a coiled conformation. The intensities of the proton signals from the gelatin decreased and the NMR spectral lines broadened upon the formation of interfacial adsorption layers of gelatin (T > 313 K). The result is similar to that of collagen-like helices and gels of gelatin and shows that the fraction of mobile gelatin segments in interfacial adsorption layers decreases virtually to zero. The presence of two different signals in the NMR spectrum suggests that benzene is solubilized by gelatin macromolecules and constitutes one component of the interfacial adsorption layer of gelatin

Effect of nonionic surfactants on the state of water in cement systems (by NMR Relaxation Data). 1. The state of water in the course of structure formation

The state of water in bound-disperse structures formed in the course of cement hardening and the effect of surfactants [polyethylene glycol (PEG), polypropylene glycol (PPG), and hexanol] on this state and also the state of water in freely-disperse structures in hydrated cements in the presence of the same surfactants at different extents of their adsorption were studied by the NMR relaxation technique. It is established that, in the semilog scale, the envelope of spin-echo signals from protons in the samples with a water-to-cement ratio of 0.3 can be decomposed into three components (for samples containing PPG or hexanol additives, into four components) corresponding to protons of different water fractions varying in the course of formation of the structure of cement stone. The maximum change with time was found for the occupancy of the shortest T2 component. During several hours of cement hardening, the occupancy of this water fraction ranged up to 96 - 97% (from the total signal of water protons). Consideration of adsorption isotherms and NMR relaxation data for samples containing PPG and hexanol additives suggests that the mobility of water molecules, which determine the intermediate T2 components, is associated with the behavior of water near the interface in the presence of adsorbed substances. It is shown that, in the presence of additives, boundary layers of water are changed. At the end of the second week of the hardening process, the fraction of the short T2 component ranged up to 78 - 84% from the total proton signal. A scheme of the water distribution in pores of cement stone in the presence of additives and its interrelation with relaxation processes are discussed