Cauchy problem for perfectly conducting viscous magnetofluid in general relativity

In recent years evidence has been accumulating that shows that in the early universe matter was in the dense plasma state, possibly associated with a strong primordial magnetic field. It has also been shown that the effect of particle creation at this epoch is equivalent in macroscopic theory to the effect of viscosity, of which shear viscosity was much more important and which may have removed some anisotropy present initially. The aim of this paper is to study the Cauchy problem for a perfectly conducting viscous magnetofluid assuming the pressure and coefficients of viscosity to be functions of the density alone. We also study the consistency conditions satisfied by four unknown quantities on the initial Cauchy hypersurface and show that hydrodynamic and Alfvén waves cannot be differentiated, unlike what occurs in a perfect magnetofluid.     

“Pauli effect” in relativity

Abraham's electromagnetic energy-momentum tensor predicts a force term additional to that given by Minkowski. We show that a symmetric energy-momentum tensor derived by Taub from a general variational principle also predicts this “Pauli effect”.     

A Concise Synthesis of the DNA‐Intercalating and Antimalarial Alkaloid Cryptolepine and Its Fluorescence Behaviour in Solvents of Different Polarities

A microwave‐induced rapid and facile synthesis of the DNA‐intercalating and antimalarial drug cryptolepine is described. The key step in this synthesis involves the aqueous‐phase base‐catalyzed condensation of isatin and 1‐acetyl‐1H‐indol‐3‐yl acetate which has been simplified and expedited by dielectric heating, employing an ordinary domestic microwave oven. The method transforms the synthesis of an important drug molecule from a prohibitively lengthy process to a matter of a few minutes with a much improved yield. Dual absorption and fluorescence is observed from the molecular system in solvents of different polarity thus providing valuable insight into its binding modes toward protein or DNA.     

Separation of polar and steric effects in the oxidation of ortho-substituted benzaldehydes by N-bromobenzamide

The kinetics of the oxidation of twelve ortho-substituted benzaldehydes by N-bromobenzamide (NBB) to the corresponding benzoic acids have been studied. The reaction is first order with respect to NBB, the aldehyde and hydrogen ions. The addition of benzamide has no effect on the reaction rate. (PhCONH₂Br)⁺ has been postulated as the reactive oxidising species. The correlation of rates with the single substituent-parameter equations is poor. The correlation with Charton’s equation of inductive, resonance and steric parameters is satisfactory. However, excellent correlations were obtained, when Charton’s steric parameter was used along with Taft’s σ₁; andσ _R ⁺ substituent constants. The polar reaction constants have negative values. The reaction is subject to steric hindrance by the ortho-substituents.     

Growth and microstructure for visible emission and surface optical phonon mode of Zn–ZnO nanostructure

The Zn–ZnO nanostructured thin films were prepared in carbon matrix using a cost-effective vacuum-carbon arc method. On increasing graphitization with ZnO, the grazing incidence X-ray diffraction pattern showed that the intensity of the ZnO peak increases, whereas that of the Zn peak decreases. X-ray line profile analysis and transmission electron microscopy were employed to investigate the microstructural evolution of Zn–ZnO nanostructure during vacuum arc processing. A growth mechanism is proposed for the Zn–ZnO nanostructure when reaction with carbon-containing gas inside the reactor wall takes place. Detailed studies of photoluminescence bands clearly exhibit the intensity variation of violet and blue-green bands on increasing graphitization ratio. Using the dielectric continuum approach, surface optical phonon modes of the Zn–ZnO nanostructure were studied for different synthesized samples.     

A novel biflavonyloxymethane from Pongamia pinnata and its radical quenching activity

The root bark of Pongamia pinnata Pierre (syn P. glabra Vent.) has afforded a new biflavonyloxymethane, pongabiflavone, along with a known furanoflavone, 3-methoxy-(7, 8, 2", 3") furanoflavone. The structure of this new compound was elucidated from extensive spectral studies, including 2D-NMR spectroscopic experiments. The antioxidant, radical quenching activity- superoxide and nitric oxide quenching activities of both pongabiflavone and previously isolated karanjabiflavone have been evaluated which can be a key to cure Psoriasis.     

Seven-coordinate anion complex with a tren-based urea: binding discrepancy of hydrogen sulfate in solid and solution states

Structural characterization of a hydrogen sulfate complex with a tren-based urea suggests that the anion is coordinated with six NH···O bonds (d(N···O) = 2.857 (3) to 3.092 (3) ?) and one OH···O bond (d(O···O) = 2.57 (2) ?) from three receptors; however, in solution the anion is bound within the pseudo-cavity of one receptor.     

Structural Elucidation of Isomeric Pyranoflavones by 2D-Noesy

Abstract

Unequivocal assignments of the uncoupled protons at H-3 and H-6/H-8 of pyranoflavones by 2D-NOESY experiments have made it possible to distinguish linear and angular isomers. This study also suggests that the linear structure (carpachromene, 1) assigned to a pyranoflavone isolated from Atalantia ceylanica should be revised to angular form (atalantoflavone, 4). 2D-NOESY is also useful for differentiating 3′4′- and 2′4′- disubstituted B-ring flavones.     

Stereochemical Assignment of Tertiary Hydroxyl Group in Diterpene Furan Glycosides by Pyridine Induced Shifts, 13C- and 2D-NMR Spectroscopy

The stereochemistry of the tertiary hydroxyl group in diterpene furan glycosides viz. cordifolisides D (1) and cordifoliside E (2) has been assigned on the basis of pyridine solvent induced shifts (PIS) in the ¹H and ¹³C NMR spectra. The methyl and the methylene groups occupying positions vicinal, 1,3-diaxial and geminal to the tertiary hydroxyl group were deshielded to different extent depending on the dihedral angle. The stereochemical assignments are well supported by ¹³C-γ shifts and 2D Overhauser spectroscopy.