The construction of reciprocity and integral representation formulas of the general solution for quasistatic and dynamic problems of uncoupled generalized thermoelasticity

Reciprocity formulas are constructed and representations of the Somigliani-type are obtained for quasistatic and dynamic problems of uncoupled generalized thermoelasticity in the Lord-Shulman formulation that is effective for applications. Moreover, representations are obtained for the stresses and heat flux. Unlike the existing approach (/1/, say) these formulas are derived on the basis of an examination of the system of differential equations of the above-mentioned problems of generalized thermoelasticity as a system with appropriate non-selfadjoint differential operators. Operators adjoint to the initial differential operators are introduced into consideration for the construction of the reciprocity formulas (second Green's formula), and a Laplace transformation is used.     

The photolysis and radiolysis of H2S−CH4 gas-phase mixture

The purification of methane from hydrogen sulphide at room temperature as affected by U.V.-light and ionizing radiation has been studied. A probable reaction mechanisms is discussed.     

Deuteron electromagnetic form factors and tensor polarization observables in the framework of the hard-wall AdS/QCD model

We study the electromagnetic form factors and tensor polarization observables of the deuteron in the framework of the hard-wall AdS/QCD model. We find a profile function for the bulk twist \begin{document}$\tau=6$\end{document} vector field, which describes the deuteron on the boundary and fix the infrared boundary cut-off of AdS space in accordance with the ground state mass of the deuteron. We obtain the deuteron charge monopole, quadrupole, and magnetic dipole form factors and tensor polarization observables from the bulk Lagrangians for the deuteron and photon field interactions. We plot the momentum transfer dependence of the form factors and tensor polarization observables and compare our numerical results with those in the soft-wall model and experimental data.     

Vibrational distribution functions and relaxation rate in anharmonic-oscillator systems

Analytical expressions were derived for the vibrational distribution function in a system of anharmonic oscillators under conditions where the supply of vibrational energy considerably exceeded the equilibrium value. Distribution was found by considering the effect of vibrational-vibrational and vibrational-translational energy exchange, as well as spontaneous radiative transitions. Analytical expressions were also obtained for the relaxation rate of vibrational energy. It was shown that where there is a strong deviation from equilibrium this rate can significantly exceed the corresponding value for a model of harmonic oscillators and is determined by the probability of vibrational-vibrational exchange in the molecules.     

Manganese-depleted/reconstituted photosystem II core complexes in solution and liposomes

Chlorophyll fluorescence transients measurements were employed to study the functioning of spinach photosystem II (PS II) core complexes in solution or reconstituted into liposomes. Lipid vesicles were prepared from soybean phospholipids (asolectine) or a mixture of spinach thylakoid lipids. In comparison with intact PS II core complexes comprising two distinct fluorescence phases, designated as O-J and J-P, complete suppression of the latter phase in Mn-depleted samples was observed. An increase of magnitude of the J-P phase in the presence of exogenous MnCl(2) (4 Mn/RC) indicate in favor of partial restoring of oxygen-evolution activity of PS II. The J-P phase observed in PS II in solution was characterized by a lifetime of ~320 ms, while in liposome-reconstituted samples this phase was accelerated up to ~20 ms in case of asolectine and up to ~9 ms in case of a mixture of thylakoid lipids. These data clearly suggest that lipid environment stimulates the steady-state rate of oxygen evolution. The effect of lipids is likely based on keeping the embedded proteins in optimal structure for efficient functioning.     

Benzimidazoles and related heterocycles 10. A novel acid-catalyzed rearrangement in the system 3-(α-aminobenzyl)quinoxalin-2(1H)-one-ethyl acetoacetate as a simple and efficient method for synthesizing 2-(pyrrol-3-yl)benzimidazoles

A reaction of 3-(α-aminobenzyl)quinoxalin-2(1H)-one with ethyl acetoacetate in boiling acetic acid is accompanied by contraction of the pyrazine ring. A rearrangement involving the fragment C(2)-C(3)-C(NH₂)Ph of the quinoxaline system and the fragment C(2)-C(3) of ethyl acetoacetate yields 2-(4-ethoxycarbonyl-5-methyl-2-phenylpyrrol-3-yl)benzimidazole. Possible pathways of this reaction are considered.     

Pyrrolo[1,2-<Emphasis Type="Italic">a</Emphasis>]quinoxalines based on pyrroles (Review)

Published data on methods for the synthesis of pyrrolo[1,2-a]quinoxalines, based on derivatives of pyrroles and also on compounds not originally derivatives of quinoxalines or pyrroles, are reviewed and classified.     

Influence of calcium-induced aggregation on the sensitivity of aminobis(methylenephosphonate)-containing potential MRI contrast agents

A novel class of 1,4,7,10-tetraazacyclododecane-1,4,7-tris(methylenecarboxylic) acid (DO3A)-based lanthanide complexes with relaxometric response to Ca(2+) was synthesized, and their physicochemical properties were investigated. Four macrocyclic ligands containing an alkyl-aminobis(methylenephosphonate) side chain for Ca(2+)-chelation have been studied (alkyl is propyl, butyl, pentyl, and hexyl for L(1), L(2), L(3), and L(4), respectively). Upon addition of Ca(2+), the r(1) relaxivity of their Gd(3+) complexes decreased up to 61% of the initial value for the best compounds GdL(3) and GdL(4). The relaxivity of the complexes was concentration dependent (it decreases with increasing concentration). Diffusion NMR studies on the Y(3+) analogues evidenced the formation of agglomerates at higher concentrations; the aggregation becomes even more important in the presence of Ca(2+). (31)P NMR experiments on EuL(1) and EuL(4) indicated the coordination of a phosphonate to the Ln(3+) for the ligand with a propyl chain, while phosphonate coordination was not observed for the analogue bearing a hexyl linker. Potentiometric titrations yielded protonation constants of the Gd(3+) complexes. log K(H1) values for all complexes lie between 6.12 and 7.11 whereas log K(H2) values are between 4.61 and 5.87. Luminescence emission spectra recorded on the Eu(3+) complexes confirmed the coordination of a phosphonate group to the Ln(3+) center in EuL(1). Luminescence lifetime measurements showed that Ca-induced agglomeration reduces the hydration number which is the main cause for the change in r(1). Variable temperature (17)O NMR experiments evidenced high water exchange rates on GdL(1), GdL(2), and GdL(3) comparable to that of the aqua ion.     

A new algorithm for accurate evaluation of the generalized Bloch–Gruneisen function and its applications to MgB2 superconductor

The objective of this Letter is to provide an efficient and reliable analytical procedure for the generalized Bloch–Gruneisen function with the Debye temperatures for the wide temperature range using the binomial expansion theorems. As will be seen, the present formulation yields compact closed-form expressions which enable the ready calculation of Bloch–Gruneisen function for integer and noninteger values of parameter m. The proposed procedure guarantees the reliable application of the contribution of electron–photon interaction to the electrical resistivity of metals. Finally, the algorithm is used to simulate the variation of the resistivity and thermal conductivity against temperature sintered polycrystalline MgB₂. Furthermore, the comparison of the method with numerical calculations demonstrates the applicability and accuracy of the method.     

Asymmetric Synthesis of Chiral Norbornenes from Polybromocyclopentadienes

Effect of the conditions on the enantiomeric purity, overall yield, isomeric composition ofchiral polybromonorbornene Diels-Alder adducts of polybromocyclopentadienes and (-)-menthyl acrylatewas studied. Enantiomerically pure polybromonorbornenecarboxylic acids were obtained by resolution of the corresponding racemates through diastereoisomeric salts with l-ephedrine. The structure of the products was confirmed by the IR and ¹H NMR spectra.