Influence of qualitatively different fats on the level of cholesterol and phospholipids in the blood serum and liver on rats in choline-protein insufficiency]

The effect of lard and sunflower oil making part of a cirrhogenic ration with a high content of fat and deficient protein and choline on the level of total and esterified cholesterol and phospholipids in the blood serum and liver was studied. The experiments lasted for 150 and 210-240 days. Changes in the level of cholesterol and phospholipids in the blood serum and liver of the rats were noted to occur from the first days of developing fat dystrophy (fatty degeneration) of the liver, these changes gaining in intensity with lengthening of the test periods and progressive development of the pathological process. The quality of the fat influenced the extent of the upset cholesterol and phospholipids metabolism, since the saturated fat which accelerated and intensified the development of lipohepatosis and cirrhosis caused a significantly greater accumulation of the cholesterol ethers in the liver and reduction of these ethers, as well as of phospholipids in the serum. An addition of choline to the rations prevented the development of lipohepatosis, but failed to avert upsets of the lipids metabolism.     

Effect of lead oxide on the dielectric characteristics of heterogeneous Pb(Zr, Ti)O3 + PbO films obtained by a two-stage method

We have studied changes in the dielectric properties of thin lead zirconate titanate Pb(Zr,Ti)O₃ (PZT) films, obtained using a two-stage ex-situ technology, as dependent on the microstructure of a perovskite phase and the content of microinclusions of excess lead oxide. The presence of these microinclusions leads to either anomalously low or high values of dielectric permittivity and anomalous pyroelectric response.     

Hydroxyapatite-calcium carbonate ceramic composite materials

Hydroxyapatite/calcium carbonate (CC) composite powders containing up to 50 wt % CO₃²⁻, have been prepared via precipitation from aqueous solutions. According to chemical analysis data, the CO₃²⁻ content of the powders coincides with the intended one over the entire composition range studied. With increasing CO₃²⁻ content, the specific surface area of the powders decreases because of the formation and growth of large needlelike CC crystals up to 1.5 μm in size. The addition of low-melting-point alkali carbonates to the starting powder mixture reduces the sintering temperature of the powders to below 720°C, thereby preventing the thermal decomposition of CC. The highest bending strength, up to 76 MPa, is offered by the materials with the lowest CC content, about 20 wt %, and an average crystal size of 100 nm. The solubility of the composites gradually increases with CC content. In vitro experiments with a human fibroblast model (MTT test) demonstrate that the composites have zero cytotoxicity.     

Modified polypropylene yarns from oriented film for manufacture of goods for national consumption and technical articles

Conclusions A technological process has been developed for preparing modified film yarns from a mixture of polypropylene and low density polyethylene having a content of the latter up to 10% by wt.; these yarns are used to make goods for national consumption or technical articles, with an economic advantage of 50 rubles per metric ton of yarn.When small additions of LDPE are introduced into polypropylene, an increase in the degree of yarn stretch is observed.The suggestion has been made that small additions of LDPE heal defects in the structure of oriented polypropylene, which is prone to spontaneous fibrillation; this aids in obtaining yarns with increased strength, elasticity, and lower tendency to split.Translated from Khimicheskie Volokna, No. 1, pp. 45–47, January–February, 1989.     

Towards development of colorimetric test-systems for phenols detection based on computationally-designed molecularly imprinted polymer membranes

Colorimetric test-system for the express-control of phenols content in water was developed. The system consisted of free-standing molecularly imprinted polymer (MIP) membranes which contained synthetic binding sites capable of phenol binding. The MIP membranes were obtained by co-polymerisation of a functional monomer (e.g. itaconic acid, 2-acrylamido-2-methyl-1-propanesulfonic acid, acrylamide or methacrylic acid) with triethyleneglycoldimethacrylate and oligourethaneacrylate. Rational choice of the functional monomers was based on the results of computational modelling. The phenol-selective MIP membranes were used as a basis for the colorimetric test-system for measuring phenol in aqueous samples. Phenol molecules were selectively adsorbed by the MIP membranes and quantified using color reaction with 4-aminoantipyrine. The intensity of the membranes' staining was proportional to the phenol concentration in the analysed sample. The optimised colorimetric test-system based on MIP membranes demonstrated a low detection limit (50 nM), a wide working range — 50 nM–0.5 mM and an excellent storage stability at room temperature (12 months). As compared to the traditional methods of phenols detection the developed test-system is superior because of simplicity of operation, small size and low cost.     

Thermomechanical interaction of the technological-channel tubes and graphite-bed elements of channel reactor

Translated from Atomnaya Énergiya, Vol. 68, No. 4, pp. 236–241, April, 1990.