Binuclear ladder-type complexes as building blocks for the synthesis of novel polynuclear systems

Summarized are reactivity studies of binuclear ladder complexes in the metallation reaction that has been applied to prepare novel homo- and heteropolynuclear transition metal complexes. The electron transfer through π-ligand-metal-σ,π-ligand-metal chain has been studied by IR spectroscopy and cyclic voltammetry techniques.     

Enzyme activation and inactivation induced by low doses of irradiation

Activation phenomenon has been observed with two sets of enzymes under the conditions of low dosage irradiation. Activation was registered for angiotensin-converting enzyme under in vitro γ-irradiation (0.662 MeV, pulse duration approx 10s) at dose levels of 1–3 Gy and under X-ray irradiation (approx 9 keV, pulseduration approx 10^?9s) at dose levels of 2×10^?5 Gy. An activation effect has also occurred for native and recombinant horseradish peroxidase and tobacco peroxidase under γ-irradiation. The phenomenon observed is rationalized in terms of a kinetic model suggesting the existence of at least one activated enzyme conformation induced by radiolysis. The activity oscillations registered in dense plasma focus experiments were rationalized using the same model with the corresponding kinetic equation converted into the form describing the decaying oscillations caused by exciting force. The model analysis is presented.     

Asymptotic expansions for the distribution of the crossing number of a strip by a Markov-modulated random walk

We obtain complete asymptotic expansions for the distribution of the crossing number of a strip in n steps by sample paths of a random walk defined on a finite Markov chain. We assume that the Cramér condition holds for the distribution of jumps and the width of the strip grows with n. The method consists in finding factorization representations of the moment generating functions of the distributions under study, isolating the main terms in the asymptotics of the representations, and inverting those main terms by the modified saddle-point method.     

Generalization and application of the Eisenstein reciprocity law

A generalization of the Eisenstein reciprocity law is obtained and applied to give a short proof that if N is odd, then any integer congruent to the Nth power of an integer modulo p for almost every prime p is the Nth power of some integer.     

Synthesis and oxidation of 2-furyl-4-R-substituted and furo[3,2-<Emphasis Type="Italic">c</Emphasis>]-condensed 1,2,3,4-tetrahydro-1,10-phenanthrolines and quinolines*

2-Furyl-4-substituted and furo[2,3-c]-condensed 1,2,3,4-tetrahydro-1,10-phenanthrolines were obtained for the first time from 8-aminoquinolines using the Povarov reaction. Various oxidizing agents were shown to effect the elimination of the substituent at C(4) with subsequent aromatization of the tetrahydroquinoline fragment. * Dedicated to Professor Aleksei V. Varlamov of the Russian Peoples Friendship University on the occasion of his seventieth jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 383–392, March, 2009.     

Calculation of the binding energy in negative ions of heavy elements

A calculation is made of the binding energy of an electron in negative ions of complex heavy Ga, In, Tl atoms in terms of the polarization potential formalism and the relativistic perturbation theory with a model potential of the zeroth-order approximation. The results obtained refine the literature data on the negative ions investigated. Odessa Hydrometereological Institute, 15, L'vovskaya St., Odessa, 270016, Ukraine. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 1, pp. 116–119, January–February, 1999.     

Modification of epoxy-4,4′-isopropylidenediphenol resins with phosphorylated methacrylates for preparing compounds of the interpenetrating polymer network type

Phosphorylated methacrylates were prepared by reaction of butylphosphoric acids and their salts with glycidyl and β-chloroethyl methacrylates. The modifying properties of these substances toward epoxy-4,4′-isopropylidenediphenol resins ED-16 and ED-20 were examined. The physicochemical characteristics and heat resistance of the composites obtained were studied in relation to the structure of methacrylates, curing agent used, formulation, and curing conditions.     

Thermal conductivity of the amorphous and nanocrystalline phases of the beech wood biocarbon nanocomposite

Natural composites (biocarbons) obtained by carbonization of beech wood at different carbonization temperatures T _carb in the range of 800–2400°C have been studied using X-ray diffraction. The composites consist of an amorphous matrix and nanocrystallites of graphite and graphene. The volume fractions of the amorphous and nanocrystalline phases as functions of T _carb have been determined. Temperature dependences of the phonon thermal conductivity κ(T) of the biocarbons with different temperatures T _carb (1000 and 2400°C) have been analyzed in the range of 5–300 K. It has been shown that the behavior of κ(T) of the biocarbon with T _carb = 1000°C is controlled by the amorphous phase in the range of 5–50 K and by the nanocrystalline phase in the range of 100–300 K. The character of κ(T) of the biocarbon with T _carb = 2400°C is determined by the heat transfer (scattering) in the nanocrystalline phase over the entire temperature range of 5–300 K.