New method for the preparation of O-carbamoyl derivatives in the 4-hydroxyaminoimidazolidin-2-one series

The corresponding 4-(O-carbamoylhydroxyamino)imidazolidin-2-ones were obtained by cyclization of O,N-dicarbamoyl derivatives of N-(3-oximino-2-methyl-2-butyl)- and N-(1-oximino-2-cyclohexyl)methylamines in alkaline media. It was shown that the carbamoylation of 1-methyl-4,5-tetramethylene-3-(3,4-dichlorophenyl)-4-hydroxy-aminoimidazolidin-2-one gives, respectively, an O- or N-carbamoyl derivative, depending on whether it is carried out in alkaline or neutral solutions.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 399–401, March, 1984.     

Effects of Ultraviolet Radiation (UVA+UVB) and Copper on the Morphology,Ultrastructural Organization and Physiological Responses of the Red Alga Pterocladiella capillacea

The effect of ultraviolet (UV) radiation and copper (Cu) on apical segments of Pterocladiella capillacea was examined under two different conditions of radiation, PAR (control) and PAR+UVA+UVB (PAR+UVAB), and three copper concentrations, ranging from 0 (control) to 0.62, 1.25 and 2.50 μm . Algae were exposed in vitro to photosynthetically active radiation (PAR) at 70 μmol photons m^?2 s^?1, PAR + UVB at 0.35 W m^?2 and PAR +UVA at 0.70 W m^?2 during a 12‐h photocycle for 3 h each day for 7 days. The effects of radiation and copper on growth rates, content of photosynthetic pigments and photosynthetic performance were analyzed. In addition, samples were processed for light and transmission electron microscopy. The content of photosynthetic pigments decreased after exposure to radiation and Cu. Compared with PAR radiation and copper treatments modified the kinetics patterns of the photosynthesis/irradiance curve. The treatments also caused changes in the ultrastructure of cortical and subcortical cells, including increased cell wall thickness and accumulation of plastoglobuli, as well as changes in the organization of chloroplasts. The results indicate that the synergistic interaction between UV radiation and Cu in P. capillacea, led to the failure of protective mechanisms and causing more drastic changes and cellular imbalances.     

Surface tension in field theory at finite temperature: Semiclassical fermionic plus bosonic contributions

We compute, within the one loop approximation, the temperature dependent surface tension for a model involving a scalar field coupled to a fermionic field. The fermionic and bosonic contributions have been computed in this approximation by evaluating explicitly the determinants in the presence of a domain wall.     

Electrochemical oxidative dimerization of acetoacetic and benzoylacetic esters in the presence of metal halides

Acetoacetic and benzoylacetic esters dimerize on electrolysis in the presence of metal halide mediators to form 2,5-dioxohexane-3,4-dicarboxylic and 1,4-dioxo-1, 4-diphenylbutane-2,3-dicarboxylic esters in yields up to 90%. Primarily the meso-form of the dimer is produced (up to 90%) under optimal conditions (NaI, –20°C) in acetone and acetonitrile. Diastereomers of the dimer are produced in comparable amounts in methanol and ethanol.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2536–2540, November, 1991.     

Molecular-crystalline approach to evaluation of correlation corrections in the theory of chemical bonding in crystals: Electronic structure of Ti2O3 crystals

The problem of the partial inclusion of electron correlation effects has been considered in the framework of the unrestricted Hartree-Fock method. The calculation of the electronic structure of the [Ti₂O₉]^12? cluster is performed. The results obtained demonstrate that, in some cases, a major part of static correlation effects can be taken into account in the unrestricted Hartree-Fock approximation. The influence of these effects on the local characteristics of crystals is analyzed.