Overtone spectra of aniline derivatives

Overtone spectra of 2-ethylaniline, N-methylaniline, N-ethylaniline, N,N-dimethylaniline and N,N-diethylaniline have been studied in 2500-15000 cm(-1) region. Vibrational frequency and anharmonicity constants for aryl/alkyl C-H stretch and N-H stretch vibrations have been determined. The effect of substitution of C(2)H(5) group on the ortho position in the ring and CH(3)/C(2)H(5) at the positions of the H-atom in NH(2) group has been studied in these molecules. It is noted that the aryl C-H stretching frequency and the N-H stretching frequency is appreciably increased due to the replacement of H in NH(2) group by CH(3)/C(2)H(5). These experimental observations are well supported by theoretical calculations for charge density on N-atom using molecular orbital AM(1) method.     

Production,Purification and Characterisation of a Potential Fibrinolytic Protease from Endophytic <Emphasis Type="Italic">Xylaria curta</Emphasis> by Solid Substrate Fermentation

The present investigation highlights the optimal conditions for production of a non-toxic, bi-functional fibrinolytic enzyme xylarinase produced by endophytic fungus Xylaria curta by solid substrate fermentation using rice chaff medium. The purified enzyme is a monomeric protein with a molecular mass of ～33 kDa. The enzyme exhibits cleavage of Aα and Bβ chains of fibrin(ogen) and has no effect on γ chain. The optimal fibrinolytic activity of the enzyme was observed at 35 °C and pH 8. The fibrinolytic activity was enhanced in the presence of Ca²⁺, whereas it was completely inhibited in the presence of Fe²⁺ and Zn²⁺ ions and inhibitors like EDTA and EGTA suggesting it to be a metalloprotease. The K _m and V _max of the enzyme for azocasein were 326 μM and 0.13 μM min^?1. The N-terminal sequence of the enzyme (SNGPLPGGVVWAG) was same when compared to xylarinase isolated from culture broth of X. curta. Thus, xylarinase could be exploited as a potent clot busting enzyme which could be produced on large scale using solid substrate fermentation.     

Synthesis and characterization of some oxovanadium(V) complexes with internally functionallized oximes. Crystal and molecular structure of heptacoordinated [VOCl{ON=C(CH3) (C4H3S-2)}2] · CH3OH

New heteroleptic oxovanadium(V) chloro oximato complexes of the type [VO{Cl}_3-n {ON=C(CH₃)(Ar)} _n ] (where Ar = C₄H₃O-2, C₄H₃S-2, C₅H₄N-2 and n = 1 or 2) have been synthesized in excellent yields by the reaction of VOCl₃ with the sodium salts of corresponding internally functionallized oximes in refluxing anhydrous benzene. The complexes are characterized by elemental analyses and spectroscopic techniques (FT-IR, ¹H-, ¹3C{¹H}- and ⁵¹V-NMR). FAB mass spectral analysis of one of the derivatives, [VOCl{ON=C(CH₃)C₄H₃S}₂] indicates the monomeric nature of the complex. ⁵¹V-NMR spectral studies of these complexes suggest tetra-coordination around the vanadium atom in solution. However, the single crystal X-ray diffraction study of a redistribution product [VOCl{ON=C(CH₃)(C₄H₃S-2)}₂] · CH₃OH obtained on recrystallization of [VOCl₂{ON=C(CH₃)(C₄H₃S-2)}] from a methanol-hexane mixture shows the vanadium(V) atom is hepta-coordinated with distorted pentagonal bipyramidal geometry. The oxo-atom occupies the axial position while the weakly coordinated CH₃OH group is trans to the V=O atom. The two oximato ligands in the approximate pentagonal plane are bonded to the central vanadium atom in dihapto (η²-N, O) manner with the formation of three-membered rings. The V–Cl bond occupies the fifth position in the approximate plane.     

Frequency upconversion in Pr3+-Li2O-TeO2 binary glass by decay curve analysis

Using the decay curve analysis frequency upconversion under continuous wave NIR laser radiation ( approximately 890 nm) following the non-resonant excitation at higher energies than 1G4 level has been reported. The decay curve of the antistokes emission (3P0-->3H4) shows similar behavior as that of the stokes emission (3P0-->3H4) and does not show any rise time attributing to the excited state antistokes absorption assisted by phonon emission. The covalency, bonding parameters and nephalauxetic effect for the present system has also been determined.     

Dissociation of 1P states in hot QCD Medium Using Quasi-Particle Model

We extend the analysis of a very recent work [1] to study the dissociation phenomenon of 1P states of the charmonium and bottomonium spectra (χ_c and χ_b) in a hot QCD medium using Quasi-Particle Model. This study employed a medium modified heavy quark potential which has quite different form in the sense that it has a lomg range Coulombic tail in addition to the Yukawa term even above the deconfinement temperature. Then we study the flavor dependence of their binding energies and explore the nature of dissociation temperatures by employing the Quasi-Particle debye mass for pure gluonic and full QCD case. Interestingly, the dissociation temperatures obtained by employing EoS1 and EoS2 with the Γ criterion, is closer to the upper bound of the dissociation temperatures which are obtained by the dissolution of a given quarkonia state by the mean thermal energy of the quasi-partons in the hot QCD/QGP medium.     

Photoluminescence Studies of Pr<Superscript>3+</Superscript> Doped Lead Germanate Glass

The Pr³⁺doped PbO-GeO₂ glass samples have been synthesized by melting and quenching process. The nephelauxetic ratio, covalency and bonding parameter which provides the information about the type of bonding between the rare earth ion and neighbor oxygen atoms calculated. The optical parameters such as radiative transition probabilities, radiative lifetime, branching ratios etc. of Pr³⁺ ions have been determined by Judd-Ofelt analysis. An upconversion emission using the excitation at ~594 nm supported by energy transfer process due to dipole-dipole interaction in the ¹D₂ metastable state has been found.     

Operational matrix approach for solution of integro-differential equations arising in theory of anomalous relaxation processes in vicinity of singular point

In this paper we study the numerical solution of singular Abel–Volterra integro-differential equations, which are typical for the theory of anomalous diffusion and viscoelastic delayed stresses. The proposed method is based on application of the operational and almost operational matrices to derivatives and integrals in a vicinity of the kernel’s singular point. As examples, two orthonormal systems are considered: Bernstein polynomials and Legendre wavelets. The methods convert the singular integro-differential equation in to a system of algebraic equations that implies two advantages: (i) one does not need to introduce artificial smoothing factors into the singular integrand and (ii) the direct estimation of computational error around singular point is possible via the obtained explicit expression. The examples of numerical solution and their discussion are presented.