Quantum Measurement and Dynamics

We discuss the question of dynamics in the scheme of the quantum measurement process. Especially we consider the form of the Hamiltonians describing the interaction between the observed system and the apparatus. The problem of their spectra is treated.     

Influence ofpH and concentration of complexing agents on fluorescence of europium (III) ethylenediaminetetraacetic acid and europium (III) nitrilotriacetic acid complexes in aqueous solutions

The fluorescence of aqueous solutions of Eu(III) complexes withEDTA andNTA has been investigated. Intensities of the fluorescence bands have been measured as a function of complexone concentrations in the solutions and thepH. The results are interpreted in terms of the different forms of Eu(III) complexes and their relative stabilities.

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Einfluß vonpH und Konzentration der Komplexbildner auf die Fluoreszenz der Komplexe des Europium (III) mit Ethylendiamintetraessigsäure und Nitrilotriessigsäure in wäßrigen Lösungen

Zusammenfassung Die Fluoreszenz von wäßrigen Lösungen der Komplexe des Europium(III) mit Ethylendiamintetraessigsäure und Nitrilotriessigsäure wurde untersucht. Die Intensitäten der Fluoreszenzbanden in Abhängigkeit vonpH und Konzentration der Komplexbildner wurden auf der Basis vorkommender Komplexgeometrien und deren Stabilitäten interpretiert.

     

Dynamics of a gravitationally loaded chain of elastic beads

Elastic beads repel in a highly nonlinear fashion, as described by Hertz law, when they are compressed against one another. Vertical stacking results in significant compressions of beads at finite distances from the surface of the stack due to gravity. Analytic studies that have been reported in the literature assume acoustic excitations upon weak perturbation [J. Hong et al., Phys. Rev. Lett. 82, 3058 (1999)] and soliton-like excitations upon strong perturbation [V. Nesterenko, J. Appl. Mech. Tech. Phys. 5, 733 (1983); S. Sen and M. Manciu, Physica A 268, 644 (1999)]. The present study probes the position, velocity and acceleration and selected two-point temporal correlations and their power spectra for individual beads for cases in which the system has been (i) weakly, (ii) strongly, and (iii) moderately perturbed at the surface in the sense specified in the text. Our studies reveal the existence of distinctly different dynamical behavior of the tagged beads, in contrast to conventional acoustic response, as the strength of the perturbation is varied at fixed gravitational loading. We also comment on the effects of polydispersity on system dynamics and probe the relaxation of isolated light and heavy beads in the chain. (c) 2000 American Institute of Physics.     

Deactivation of the S2 and Two Lowest Triplet States of 4H-1-Benzopyran-4-thione and Its Alkyl Derivatives in Methanol Solution

Spectral and photochemical properties of three aromatic thioketones, 4H-1-benzopyran-4-thione and its two alkyl derivatives, in their second excited singlet and two lowest triplet states have been a subject of stationary and time-resolved studies. Quantum yields of emissions from the above-mentioned states as well as lifetimes of these states have been measured. The results indicate an important role of intermolecular solvent-induced processes in deactivation of the excited states of the thioketones studied. The possible mechanism of these processes involves hydrogen atom abstraction and/or formation of exciplex. For relatively high thione concentrations, the contribution of self-quenching in deactivation of the triplet states becomes significant. The effect of the alkyl chain in a thione molecule on deactivation parameters is discussed.     

Gaussian entanglement of symmetric two-mode Gaussian states

A Gaussian degree of entanglement for a symmetric two-mode Gaussian state can be defined as its distance to the set of all separable two-mode Gaussian states. The principal property that enables us to evaluate both Bures distance and relative entropy between symmetric two-mode Gaussian states is the diagonalization of their covariance matrices under the same beam-splitter transformation. The multiplicativity property of the Uhlmann fidelity and the additivity of the relative entropy allow one to finally deal with a single-mode optimization problem in both cases. We find that only the Bures-distance Gaussian entanglement is consistent with the exact entanglement of formation.     

Study of the Separation of Dianin's Compound Formed in the Bisphenol-A Synthesis

A method of separating Dianin'scompound from a complex mixture of by-productsobtained from the bisphenol-A industrial processis described using compounds which formcrystalline clathrate structures with Dianin'scompound. Under the conditions used the clathratestructure obtained could be crystallized with highpurity (above 99.5%). The described statistical modelof mixture design shows that the highest yield ofcrystallization was found by using a single solvent(ethyl alcohol) for separation of Dianin's compound.     

Age-related waning of in vitro Interferon-γ levels against r32kDaBCG in BCG vaccinated children

Background  

Mycobacterium bovis BCG vaccine has displayed inconsistent efficacy in different trials conducted in various geographical regions. Nevertheless, it significantly reduces the risk of severe childhood tuberculosis and continues to be used to prevent tuberculosis in many countries. Many studies revealed that efficacy of vaccine wanes with age. Most of the studies were based on in vivo and in vitro responses to tuberculin. With the advent of newer tests such as in vitro interferon-γ assays and identification of potent immunogenic mycobacterial proteins there is a need to corroborate the observations. This study aims at ascertaining the need for a booster at a later age as indicated by in vitro release of IFN-γ while evaluating Ag85A as an antigen.     

Structure and molecular chirality of the acetonitrile adduct of the 2:1 salt of quinidine with biphenyl 5,5′-dinitro-2,2′-dicarboxylic acid (5,5′-dinitrodiphenic acid)

The molecule of the 21 salt consists of two quinidine cations and the 5,5-dinitrodiphenic anion. Both of the quinidine cations are protonated at the nitrogen atoms of the quinuclidine fragments. Owing to the interlocking hydrogen bonds between quinidine and the dinitrodiphenic ions, a rigid structure of the salt molecule has been formed. The alkaloid molecular conformation around the C(8)-C(9) bond is open. The conformational parameters of 5,5-dinitrodiphenic anion are considerably changed in comparison with the conformation of diphenic acid in the solid state. The absolute configuration of biphenyl 5,5-dinitro-2,2-dicarboxylic anion (R) is defined by the negative torsion angles around the line which connects the centers of both phenyl rings, and is the reverse of that observed in the diphenic acid-quinine salt. The present data confirm the observation that the chirality of the salt is controlled by the chirality of theCinchona alkaloid molecule.     

An Algorithmic Approach to the Conley Index Theory

We introduce a class of representable sets which is closed under the operations of set theoretical union, intersection, difference, and topological interior and closure. We use this class to construct an algorithm which verifies if for a given dynamical system a given set is an isolating neighborhood. In the case of a positive answer the algorithm constructs an index pair.