Path integral quantization corresponding to the deformed Heisenberg algebra

In this paper, the deformation of the Heisenberg algebra, consistent with both the generalized uncertainty principle and doubly special relativity, has been analyzed. It has been observed that, though this algebra can give rise to fractional derivative terms in the corresponding quantum mechanical Hamiltonian, a formal meaning can be given to them by using the theory of harmonic extensions of function. Depending on this argument, the expression of the propagator of the path integral corresponding to the deformed Heisenberg algebra, has been obtained. In particular, the consistent expression of the one dimensional free particle propagator has been evaluated explicitly. With this propagator in hand, it has been shown that, even in free particle case, normal generalized uncertainty principle and doubly special relativity show very much different result.     

Electron transfer reactions of nickel(III) and nickel(IV) complexes

This review narrates the electron transfer reactions of various nickel(III) and nickel(IV) complexes reported during the period 1981 until today. The reactions have been categorized mainly with respect to the type of nickel complexes. The reactivity of nickel(III) complexes of macrocycles, 2,2′-bipyridyl and 1,10-phenanthroline, peptides and oxime–imine, and of nickel(IV) complexes derived from oxime–imine, oxime and miscellaneous ligands with various organic and inorganic electron donors have been included. Kinetic and mechanistic features associated with such interactions have been duly analyzed. The relevance of Marcus cross-relation equations in the delineation of the electron transfer paths has also been critically discussed.     

A Two‐Dimensional Coordination Compound as a Zinc Ion Selective Luminescent Probe for Biological Applications

A 2D coordination compound {[Cu₂(HL)(N₃)]?ClO₄}_∞ ( 1 ; H₃L=2,6‐bis(hydroxyethyliminoethyl)‐4‐methyl phenol) was synthesized and characterized by single‐crystal X‐ray diffraction to be a polymer in the crystalline state. Each [Cu₂(HL)(N₃)]⁺ species is connected to its adjacent unit by a bridging alkoxide oxygen atom of the ligand to form a helical propagation along the crystallographic a axis. The adjacent helical frameworks are connected by a ligand alcoholic oxygen atom along the crystallographic b axis to produce pleated 2D sheets. In solution, 1 dissociates into [Cu₂(HL)₂(H₃L)]?2H₂O ( 2 ); the monomer displays high selectivity for Zn²⁺ and can be used in HEPES buffer (pH 7.4) as a zinc ion selective luminescent probe for biological application. The system shows a nearly 19‐fold Zn²⁺‐selective chelation‐enhanced fluorescence response in the working buffer. Application of 2 to cultured living cells (B16F10 mouse melanoma and A375 human melanoma) and rat hippocampal slices was also studied by fluorescence microscopy.     

Kinetics and mechanism of the reaction oftrans-cyclohexane-1,2-diamine-N N N' N'-tetra-acetatomanganate(III) with substituted thioureas in aqueous medium

Summary The kinetics of reduction of [Mn^III(cydta)]^– (where H₄cydta=trans-cyclohexane-1,2-diamine-N N N' N'-tetraacetic acid) by some thiourea reductants have been studied in aqueous solution by stopped-flow techniques in the pH ranges 2.5–4.5 and 9.2–10.2. An initial increase in absorbance followed by a steady decrease indicated the formation of a precursor complex prior to the electron transfer step. The reactions are first order in both oxidant and reductant. The observed increase in rate in going from low to high pH is attributed to the difference in reactivities of the aqua and hydroxo species of the Mn^III complex; the higher reactivity of the latter is consistent with the formation of a ligand-bridged activated species prior to electron transfer. The reactivity order for the thiourea derivatives follows the order of their reported substituent effects.     

Polyelectrolyte behavior and macromolecular properties of sodium amylopectin xanthate in dilute solution

Sodium amylopectin xanthate was prepared by xanthation of potato amylopectin in alkaline medium. The pure product was characterized by I₂ solution and ultraviolet spectra of the xanthate groups. The polyelectrolyte behavior of Na amylopectin xanthate in aqueous and salt solutions was investigated by viscometry and light scattering. Its polyelectrolyte behavior in aqueous solution as studied viscometrically was completely different from that of Na amylose xanthate, which is characteristic of linear polyelectrolyte molecules. This difference in behavior could be partly due to the branched structure of amylopectin molecule. A dissymmetry study of Na amylopectin xanthate in aqueous and salt solutions, however, showed that Na amylopectin xanthate molecule underwent expansion in water by about 1.3 times its linear dimension in 0.5M NaCl (unperturbed value). Light-scattering measurements confirmed that the Na amylopectin xanthate molecule had a polydisperse random-coil chain configuration in 0.25M NaCl. Its molecular weight, end-to-end length, and other parameters in salt and alkali solutions were also determined, and the data were then compared with those of Na amylose xanthate in the same media. The solution behavior of Na amylopectin xanthate in 1M NaOH was further investigated and linear expansion factor α, excluded volume factor A₂M _W/[η], and Flory's hydrodynamic constant φ were evaluated.     

Mechanism of azole antifungal activity as determined by liquid chromatographic/mass spectrometric monitoring of ergosterol biosynthesis

A liquid chromatography/mass spectrometry (LC/MS) method for separation and characterization of ergosterol biosynthetic precursors was developed to study the effect of Posaconazole on sterol biosynthesis in fungi. Ergosterol biosynthetic precursors were characterized from their electron ionization mass spectra acquired by a normal-phase chromatography, particle beam LC/MS method. Fragment ions resulting from cleavage across the D-ring and an abundant M - 15 fragment ion were diagnostic for methyl substitution at C-4 and C-14. Comparison of the sterol profile in control and treated Candida albicans incubations showed depletion of ergosterol and accumulation of C-4 and C-14 methyl-substituted sterols following treatment with Posaconazole. These C-4 and C-14 methyl sterols are known to be incapable of sustaining cell growth. The results demonstrate that Posaconazole exerts its antifungal activity by inhibition of ergosterol biosynthesis. Furthermore, Posaconazole appears to disrupt ergosterol biosynthesis by inhibition of lanosterol 14alpha-demethylase.     

Physicochemical and macromolecular properties of sodium amylose xanthate in dilute solution

Sodium amylose xanthate has been studied in dilute solution. Potato starch was fractionated for this purpose into amylose and amylopectin fractions. Amylose was xanthated in solution under alkaline conditions and the Na amylose xanthate was then characterized by reaction with I₂ solution and ultraviolet spectra of the xanthate groups determined. Stability of the xanthate in alkaline condition under both oxygen and nitrogen atmospheres was also investigated. From light scattering measurements of dilute salt solutions of Na amylose xanthate, the weight-average molecular weight M _w as well as the molecular dimensions were determined. In 0.11M NaCl, which conforms to the θ solvent, Na amylose xanthate molecules appear to have a random-coil configuration. Two other configurational parameters, such as the effective bond length b, and the steric factor σ, i.e., (R₀²)^1/2/(R_f² )^1/2, where (R₀²)^1/2 is the Root-mean-square end-to-end distance in the unperturbed state and (R_f² )^1/2 is the unperturbed value calculated on the assumption of free rotation about each intermonomer C? O bond of the amylose chain were also calculated and found to be 6.24 and 1.020, respectively. It is thus concluded that the amylose chain in Na amylose xanthate behaves as a typical flexible coil in dilute salt solution.     

Extraction and characterization of adenovirus

A new methodology for the extraction and characterization of proteins from Coomassie-stained sodium dodecylsulfate polyacrylamide gel electrophoresis using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) has been described. The utility of this methodology was demonstrated in the characterization of adenovirus proteins. The key steps in the extraction and destaining process involve washing the excised band with a combination of solvents that include 10% acetic acid, acetonitrile, methanol, and formic acid:water:isopropanol mixture. By using this procedure, we determined adenovirus proteins with molecular weights ranging from 10,000 to 110,000 Da by MALDI-MS, obtaining a detection limit of approximately 6 pmol. Parallel experiments were successfully carried out to analyze adenovirus proteins from Cu-stained gels. It was observed that increase in laser intensity resulted in significant improvements in the quality of MALDI mass spectra for the analysis of inefficiently destained proteins from Cu-stained gels.     

Ternary complexes of copper(II), nickel(II) and zinc(II) with nitrilotriacetic acid as a primary ligand and some phenolic acids as secondary ligands

Summary The formation of ternary complexes of the MAL^3– type [where M = Cu^II, Ni^II and Zn^II ; A = nitrilotriacetic acid (NTA); L = 1-hydroxy-2-naphthoic acid (1,2 HNA) and 2-hydroxy-1-naphthoic acid (2,1 HNA)] have been studied potentiometrically in 50% v/v aqueous — ethanol (25° and µ = 0.1). Under identical conditions the binary complexes of the 1,2- and 2,1-HNA ligands have also been examined. The values of mixed ligand formation constants K_MAL have been found to be lower than K_ML (first step formation constant of binary complexes) and even less than (second step formation constant of binary complexes).