Determination of carvedilol in human cardiac tissue by high-performance liquid chromatography

A new high-performance liquid chromatographic method has been developed for the determination of the beta-receptor blocker carvedilol in human cardiac tissue. After homogenizing tissue samples in a microdismembrator, carvedilol and the internal standard naftopidil are extracted with acetone. The extract is evaporated to dryness and reconstituted in a potassium acetate buffer of pH 3.5. Samples are cleaned up with solid-phase extraction columns. Carvedilol and the internal standard show recoveries of 69.8 +/- 12.2% and 63.9 +/- 9.34%, respectively. The linearity range for carvedilol is 0.01-0.35 ng/mg (parts per billion) tissue (wet weight), and the limit of quantitation is 0.01 ng/mg. The percentage coefficient of variation of the intra-assay varies between 1.45 and 5.38% and the interassay between 4.25 and 6.96%. To use as an application of the assay, the cardiac carvedilol tissue level in a patient on oral carvedilol therapy for congestive heart failure is reported.     

Festköperreaktionen in Chalkogenidsystemen. III. Bestimmung der Aktivierungsenergie von Pulvereaktionen aus Leitfähigkeitsglowkurven

In the case of the formation of thiospinels (MnCr₂S₄, ZnCr₂S₄ and CdCr₂S₄) a simple method for the determination of the activation energy of solid state reactions in polycrystalline samples by means of conductivity measurements is shown. The maxima and minima of conductivity (glow curve maxima and -minima) in the σ vs T-curves got by annealing with linearly increasing temperature are shifted towards higher temperatures with increasing rate of heating(q). By plotting ln (q/T) vs 1/T_σmax a straight line results. The activation energy of the reaction may be deduced from the slope of this straight line in analogy to the determination of the trap depth of electrons from glow curves observed in thermoluminescence.     

Chemistry of excited states. XI. Interpretation of photoelectron spectra by final state single CI method within semiempirical formalisms

The single excited doublet states of some small molecule cations calculated by CI method in the framework of semiempirical CNDO and INDO models are correlated with the photoelectron spectra of the parent molecules. The purity of the Koopmans transitions is used to discuss the one-particle interpretation of photoelectron bands by comparison with nonempirical many-body calculations. Furthermore, empirical relations are applied with respect to the evaluation of shake-up energies.     

Graphene with time-dependent spin-orbit coupling: truncated Magnus expansion approach

We analyze the role of an ac-driven Rashba spin-orbit coupling in monolayer graphene including a spin-dependent mass term. Using the Magnus expansion as a semi-analytical approximation scheme a full account of the quasienergie spectrum of spin states is given. We discuss the subtleties arising in correctly applying the Magnus expansion technique in order to determine the quasienergy spectrum. Comparison to the exact numerical solution gives appropriate boundaries to the validity of the Magnus expansion solution.     

Anomalous temperature dependence of the magnetic hyperfine field of99Ru in gadolinium

The magnetic hyperfine field at dilute⁹⁹Ru impurities in ferromagnetic Gd has been investigated as a function of temperature by time differential perturbed angular correlation (TDPAC) measurements. The saturation field at 11 K is H_hf(Ru Gd)=51(2) KOe. This value fits well into the systematics of 4d impurity hyperfine fields in Gd. The magnetic hyperfine field of RuGd does not follow the magnetization of the host (T_c=290 K) but vanishes abruptly at about 70 K. A similar behaviour has previously been observed for the 5d impurity Os in Gd. From first TDPAC measurements of the hyperfine interactions in the intermetallic phases of the Ru-Sc system it can not be completely ruled out that the observed collapse of the hyperfine field at 70 K is due to the formation of the intermetallic compound RuGd₃.This work has been supported by the Minister für Wissenschaft und Forschung des Landes Nordrhein-Westfalen