Photoinduced structure transformations in dichromate-impregnated denatured collagen

X-ray structure analysis shows that irradiating gelatin films containing chromates causes a spiral-coil transition in the denatured collagen molecules. The concentration and type of the chromate have substantial effects, as do the film preparation conditions. The x-ray diffraction and ESR data indicate that chromium(V) compounds formed by photoreduction from chromium(VI) ones are mainly responsible for the conformation transition. In the absence of chromium compounds, light absorbed by the gelatin macromolecules results in macroradicals on account of the photolysis in the denatured protein chains. There is no phase transition.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 24, No, 2, pp. 247–251, March–April 1988.     

Dynamic thermal decomposition of linear polymers and its study by thermo analytical methods

Kinetic schemes allowing to interprete the results of high-temperature gravimetric analysis of linear polymers are proposed. A thermoanalytical method has been developed in which the time for establishing constant temperature in the sample is reduced by 1–2 s. The method can be used to determine to what temperature the polymer can be overheated.     

Condensation of aryl bromides with styrenes,catalyzed by nickel complexes in the presence of zinc

Conclusions Condensation of aryl bromides with styrenes in acetonitrile in the presence of nickel organometallic complex catalysts and metallic zinc occurs regio- and stereoselectively to give E-stilbenes.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2508–2511, November, 1987.