Enzymatic degradation of chitosan films by collagenase

Special features of enzymatic degradation of chitosan samples prepared as films from solutions in acetic acid under the action of collagenase as a nonspecific enzyme are considered. Variations in acid concentration in the casting solution had a substantial effect on the chitosan structure in the film formed and, as a consequence, on the degree of degradation of film samples. The addition of poly(vinyl alcohol) upon the formation of a chitosan film led to an increase in the extent of enzymatic degradation of the film.     

Corrosion properties of electroplated coatings of iron-group metals

Comparative corrosion resistance of cobalt alloys with molybdenum and phosphorus was studied. It is shown that the corrosion parameters of the alloys depend on the composition and structure of coatings. It is demonstrated that the introduction of phosphorus into an alloy positively affects its corrosion resistance.     

Low temperature radiolysis of fullerene C<Subscript>60</Subscript> and its solutions in isopropylbenzene and <Emphasis Type="Italic">N</Emphasis>-vinylpyrrolidone

Low-temperature (77 K) radiolysis of solid fullerene C₆₀ and its glassy solutions in isopropylbenzene (IPB) and N-vinylpyrrolidone (N-VP) has been investigated with the use of ESR spectroscopy. Radiationchemical yields for the formation of paramagnetic centers (G _PMC, 1/100 eV) have been determined to be ∼0.001 for pure fullerene and 0.3 and 0.7 for its solutions in IPB and N-VP, respectively. The low value of G _PMC for fullerene indicates a high stability of this form of carbon. The increase in G _PMC in solutions as compared to the pure solvents (0.15 for IPB and 0.3 for N-VP) indicates the sensitizing effect of C₆₀.     

Phosphorylation of 3,4-Dichloro-5-hydroxy-2(5H)-furanone with Tributylphosphine

The reaction of 3,4-dichloro-5-hydroxy-2(5H)-furanone with 2 mol of tributylphosphine involves substitution of both chlorine atoms to form an unstable diphosphonium salt. The latter undergoes partial hydrolysis with cleavage of one of the P-C bonds, yielding finally a monophosphorylation product. A probable reaction pathway is considered in terms of quantum chemistry.     

Polarographic determination of galanthamine inUngernia victoris

Chemistry of Natural Compounds - 1. The polarographic behavior of galanthamine, lycorine, pancratine, hordenine, and dl-narwedine on a support of 0.01 N (C2H5)4NOH has been studied. 2. A...     

Quantitative determination of narwedine inUngernia victoris andU. Severtzovii

Summary A polarographic method for the quantitative determination of narwedine inUngernia victoris and a chromatopolarographic method for its determination inU. severtzovii have been proposed.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 610–612, September–October, 1975.     

Pyrroloquinolines

A method was developed for the preparation of 1H-pyrrolo [2,3-f]- and 3H-pyrrolo-[2,3-f]quinolines. Their IR and PMR spectra are described. The syn-anti isomerism of 5- and 6-quinolylhydrazones of ethyl pyruvate was studied.See [1] for communication I.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 369–376, March, 1977.