Eine neue Methode zum Nachweis von ?-Caprolactam

Zusammenfassung Zur Identifizierung des Caprolactams wurde die alkoholische Lösung von m-Dinitrobenzol angewandt, die mit konz. Kalilauge und Caprolactam eine rosaviolette Färbung gibt.     

Rabi oscillations in a partially coherent field

Both, phase and amplitude fluctuations of a laser field are taken into account. A gaussian stochastic process describing the latter one is not assumed to be delta correlated. Apart from the modification of the damping constant, known before, a significant modification of the Rabi frequency is found.     

A partly reduced system of Hamiltonian equations and the initial value problem in the Ecsk theory of gravity

It is shown that by solving 12 of the field equations with respect to the connection components and , the quantities used to describe the geometry of space-time can be divided into two sets. In the first set we have the canonical variables the time evolution of which is determined by the dynamical equations. The second set contains ten gauge variables N, N^k, , n ⁽ⁱ⁾ which can be given arbitrarily on space-time. This partial reduction of the Hamiltonian equations enabls us to discuss the initial value problem in the ECSK theory of gravity coupled to matter tensor fields. Such an analysis is performed for the phenomenological ECSK theory and for the ECSK theory coupled to: a covector matter field, the generalized Maxwell electrodynamics, and the generalized Fermi-Dirac electrodynamics. The Poisson brackets of the seven Hamiltonian constraints, which have to be satisfied by the canonical variables, are found. It is proved that they are first class.     

The twisted SU(3) group. Irreducible *-representations of the C *-algebra C(SμU(3))

Irreducible ^*-representations of C(SU(3)) are constructed for ]0, 1[. It is proved that C(SU(3)) is a type-I C ^*-algebra.     

On-line structure characterization of pyrrolizidine alkaloids in Onosma stellulatum and Emilia coccinea by liquid chromatography-ion-trap mass spectrometry

On-line structure characterization of pyrrolizidine alkaloids in two various plant species (Onosma stellulatum W.K., family Boraginaceae and Emilia coccinea Sims., family Compositae) was performed by a newly elaborated RP-HPLC ion trap MS method with atmospheric pressure chemical ionization (APCI) interface. Different PAs (N-oxides, free bases, otonecine alkaloids) isolated were separated on Waters XTerra C18 column using a gradient elution. The combination of a CE-SPE with multiple isolation and fragmentation steps for specific masses in ion trap MS detector enabled fast and sensitive analysis of various types of PAs (N-oxides and free bases). In O. stellulatum, spectra 12 various types of structures (13 different alkaloids) have been determined for the first time: leptanthine-N-oxide, lycopsamine-N-oxide, heliospathuline, lycopsamine, trachelanthamine-N-oxide, dihydroechinatine, leptanthine, heliospathuline-N-oxide, 7-acetylintermedine, uplandicine, echimidine and echimidine-N-oxide. In E. coccinea, the following types of PAs were found: platyphylline-N-oxide, platyphylline (three stereoisomers with the same MS(n) spectrum), ligularidine, neoligularidine, neosenkirkine and also previously reported senkirkine. The method elaborated can be applied in the structural analysis of PAs in newly examined plant materials or food products but further analysis is needed to determine the stereochemistry in details.     

Capillary electrophoresis-inductively coupled plasma-mass spectrometry: an attractive complementary technique for elemental speciation analysis

Some basic and practical aspects of interfacing capillary electrophoresis to inductively coupled plasma-mass spectrometry (CE-ICP-MS) are reviewed in this article with emphasis on the use of this hyphenated technique for elemental speciation analysis. The principles behind the techniques of both CE and ICP-MS are introduced. The interfacing of CE to ICP-MS is discussed including several devices and nebulizers reported in literature. A brief account of their advantages and limitations is given. The various CE-ICP-MS applications for elemental speciation analysis are also reviewed. Some issues concerning the future of CE-ICP-MS for the elemental speciation analyses are discussed.     

Fluorescence lifetimes of protochlorophyllide in plants with different proportions of short-wavelength and long-wavelength protochlorophyllide spectral forms

Dark-grown leaves of maize (Zea mays), wheat (Triticum aestivum), wild-type pea (Pisum sativum) and its light-independent photomorphogenesis mutant (lip1) have different proportions of protochlorophyllide (Pchlide) forms as revealed by low-temperature fluorescence emission spectra. Four discrete spectral forms of Pchlide, with emission peaks around 633, 640, 656 and 670 nm, could be distinguished after Gaussian deconvolution. In maize and wheat the 656 nm component was the most prominent, whereas for wild-type pea and its lip1 mutant, the 633 and 640 nm components contributed mostly to the fluorescence emission spectra. For the fluorescence lifetimes measured at 77 K a double exponential model was the most adequate to describe the Pchlide fluorescence decay not only for the Pchlide(650-656) form but also for the short-wavelength Pchlide forms. A fast component in the range 0.3-0.8 ns and a slow component in the range 5.1-7.1 ns were present in all samples, but the values varied, depending on species. The long-wavelength Pchlide(650-656) form had a slow component with a lifetime between 5.1 and 6.7 ns, probably reflecting the fluorescence from aggregated Pchlide. The short-wavelength Pchlide(628-633) form had values of the slow component varying between 6.2 and 7.1 ns. This represents a monomeric but probably protein-bound Pchlide form because the free Pchlide in solution has a much longer lifetime around 10 ns at 77 K. The contribution of different Pchlide forms to the measured lifetime values is discussed.     

Second-order conditions and constraint qualifications in stability and sensitivity analysis of solutions to optimization problems in Hilbert spaces

The concepts of the strong second-order sufficient optimality condition and of the linear independence of gradients of active constraints play a crucial role in stability and sensitivity analysis of solutions to finite-dimensional mathematical programming problems. In this paper an attempt is made to use these concepts in stability and sensitivity analysis of solutions to cone-constrained optimization problems in Hilbert spaces. The abstract results are applied to optimal control problems for affine systems subject to state-space constraints.This research was completed when the author was a visitor at the Institut für Angewandte Mathematik und Statistik of the University of Würzburg, and it was partially supported by the Deutsche Forschungsgemeinschaft (DFG); SPP Anwendungsbezogene Optimierung und Steuergung.