The normal-form (In)dependence of the adiabatic particle definitions

The adiabatic particle definition of Parker [1] has only been discussed for particular choices of the field variable and time coordinate, referred to here as the choice of a normal-form. It seems to have been implicitly assumed that the associated vacuum is independent of the normal-form chosen; we show that this is indeed the case.NATO Postdoctoral Fellow.     

(Perhalogenmethylthio)heterocyclen. XVIII . Synthese und eigenschaften von halogenierten (perhalogenmethylthio)pyrrolen

(Trifluoromethyltho)pyrroles 1-5 and (chlorodifluoromethylthio)pyrroles 6 were chlorinated by sulfuryl chloride, sulfuryl chloride/silicon dioxide, sulfuryl chloride/disulfur dichloried/aluminium trichloried to give the corresponding chloropyrroles 1a-d , 2a,b , 3a,b , 4a , 5a , and 6a-c Bromination with bromine or iodination with iodine/potassium iodide of 2, 3, 4 , and 6 yielded the derivatives 2c,d, 3c,d, 4b, 6d , and 2e, 3e, f, 4c , 6e respectively. Mixed halogenated pyrroles 3g and h were obtained from 3a and bromne or 3a and iodine/potassium iodide. During some chlorination reactions 7, 8 , and 9 were fromed in low yield asbyproducts. The ¹H-nmr, ¹⁹F-nmr and ir spectroscopic data are presented.     

Compartmental Approach for Evaluation of Plasma Kinetics and 13Co2-Exhalation after Oral Loading with L-[1-13C]Leucine

Abstract

A seven compartment model was applied for evaluation of oral L-[1-¹³C]leucine loading tests (38 μmol/kg body wt.) in healthy volunteers. The model comprises transport and absorption in stomach and gut into a central L-leucine-compartment which is connected to a protein compartment and to the compartment of the corresponding 2-oxo acid. CO₂ release from the latter occurs in a fast and a slow compartment into the central CO₂ compartment for exhalation. Using the fmins routine of MATLAB for parameter estimation, a good agreement was obtained between calculated and actually measured kinetics of ¹³C-labelled metabolites and a mean in vivo L-leucine oxidation of 0.365 ± 0.071 μmol/kg per min (n = 5) was computed. Plausibility of the model was checked by predicting in vivo leucine oxidation rates from primed continuous infusion tests (priming: L-[1-¹³C]leucine, 5 μmol/kg; NaH¹³CO₂, 1.2 μmol/kg; infusion: L-[1-¹³C]leucine, 5 μmol/kg per h). In 5 tested volunteers, the experimental L-leucine oxidation rate amounted to 0.358 ± 0.105 μmol/kg per min versus predicted 0.324±0.099 μmol/kg per min. Possible causes for some observed intraindividual variations are discussed.     

Implicit runge-kutta methods for differential inclusions

This paper is concerned with the application of implicit Runge-Kutta methods suitable for stiff initial value problems to initial value problems for differential inclusions with upper semicontinuous right-hand sides satisfying a uniform one-sided Lipschitz condition and a growth condition. The problems could stem from differential equations with state discontinuous right-hand sides. It is shown that there exist methods with higher order of convergence on intervals where the solution is smooth enough. Globally we get at least the order one.     

Alkyne gem‐Hydrogenation: Formation of Pianostool Ruthenium Carbene Complexes and Analysis of Their Chemical Character

Parahydrogen (p‐H₂) induced polarization (PHIP) NMR spectroscopy showed that [Cp^XRu] complexes with greatly different electronic properties invariably engage propargyl alcohol derivatives into gem‐hydrogenation with formation of pianostool ruthenium carbenes; in so doing, less electron rich Cp^X rings lower the barriers, stabilize the resulting complexes and hence provide opportunities for harnessing genuine carbene reactivity. The chemical character of the resulting ruthenium complexes was studied by DFT‐assisted analysis of the chemical shift tensors determined by solid‐state ¹³C NMR spectroscopy. The combined experimental and computational data draw the portrait of a family of ruthenium carbenes that amalgamate purely electrophilic behavior with characteristics more befitting metathesis‐active Grubbs‐type catalysts.