New possibilities of X-ray nanocrystallography of biological macromolecules based on X-ray free-electron lasers

X-ray serial nanocrystallography is a new technique for determining the three-dimensional structure of biological macromolecules from data on the diffraction of ultrashort pulses generated by X-ray free-electron lasers. The maximum achievable resolution for a set of experimental data as a function of the sample sizes and parameters of the equipment is estimated based on simulations of the diffraction process with allowance for changes in the electronic structure of the atoms of the sample under the influence of X-rays. Estimates show that nanocrystallography greatly enhances the possibilities of X-ray analysis, reducing the requirements for the minimum permitted size of the crystals and enabling to explore poorly crystallizable molecular objects, such as many membrane proteins and complexes of macromolecules.     

Modified fluororubbers based on SKF-26: Relaxation and mechanical properties

Samples of SKF-26 fluororubber modified by incorporating pendant methoxy groups into the macromolecular chain were studied by dielectric spectroscopy and dynamic mechanical analysis.     

Rotational dependences of line half-widths for CO and CO2 confined in SiO2/Al2O3 xerogel

The absorption spectra of CO and CO₂ confined in nanopores of SiO₂/Al₂O₃ xerogel have been measured using a Bruker IFS-125 HR Fourier spectrometer. Dependences of the half-width values on rotational quantum numbers and the line shift mean values are studied and compared with the data available in literature. Possible causes which can affect the rotational dependences are discussed.     

Polarization reflection holographic gratings in azobenzene-containing gelatine films

We have written polarization reflection holograms in an azobenzene-containing material. Two waves with circular polarization were used to record the gratings; the light resulting from their overlap induces chirality in the samples. The holographic reflection of the polarization gratings has the properties of Bragg reflection in cholesteric liquid crystals.     

Reaktions-f?higkeit und physkalisch-chemische Charakterisierung der Aktivzentren im System Isopren/Lithiumoligoisoprenyl/Dimethoxy?than/Hexan

Ohne Zusammenfassung     

Benzazoles and naphthazoles XXXIV. Synthesis of mono-, di-, and triheterylformazans by autooxidation of 2-hydrazinobenzazoles

Mono-, di-, and triheteiylformazans were obtained by the autooxidative coupling (in pyridine solution) of 1-alkyl-2-hydrazinobenzimidazoles with the aryl(azolyl)hydrazones of aliphatic or heterocyclic aldehydes.See [1] for communication XXXIII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 390–392, March, 1972.     

Redox reactions in a number of pyrrole-ring-substituted 5-hydroxyindoles

Some 3-substituted 5-hydroxyindoles are smoothly hydrogenated in acid media in the presence of a palladium catalyst to the corresponding indolines, which in turn are readily oxidized by air oxygen in aqueous solutions at pH 10 to the corresponding 5-hydroxyindoles.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1058–1061, August, 1971.     

Reaction of 1-vinylpyrazoles with tetracyanoethylene

It was shown that in the reaction of tetracyanoethylene with 1-vinylpyrazoles in aprotic solvents, one of the first stages involves the formation of - complexes. The final products of the reaction are 1-(2,2,3,3-tetracyano-1-cyclobutyl)pyrazoles.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 924–926, July, 1989.