Aglairubine: Structure Revision of a Chemotaxonomically Interesting Bisamide in Aglaia (Meliaceae)

 The bisamide aglairubine was isolated from different Aglaia species. The original structure was revised on the basis of FDMS and 2D-NMR data. Since all isolates were obtained from species belonging to the section Amoora of the genus Aglaia, aglairubine might serve as a taxonomic marker.     

Assessment of mitral regurgitation by magnetic resonance imaging

To evaluate the potential of magnetic resonance imaging (MRI) in detection and quantification of mitral regurgitation, 26 pts. with echocardiographically or angiographically documented mitral regurgitation were examined using a 0.5 Tesla superconducting magnet. In each patient a multislice-multiphase study in a sagittal-coronal double angulated projection (four-chamber view equivalent) was performed to assess left and right ventricular volumes, ejection fraction and regurgitant fraction. Additionally a blood flow sensitive cine-study (fast field echo: FFE) was done to visualize direction and area of regurgitant jet. MRI data were compared with quantitative and qualitative assessment of mitral regurgitation by angiography, 2D echocardiography, Doppler sonography and color flow mapping. Using the FFE mode MRI was able to detect the regurgitant jet as a typical signal loss within the left atrium in all patients. The ratio of regurgitant jet area/left atrium area as determined by MRI showed a correlation with a comparable ratio from color Doppler sonography of R = 0.87 (p < 0.001). There was also good agreement in semiquantitative grading of mitral regurgitation between MRI and angiography (R = 0.77, p < 0.001). The determination of left and right ventricular stroke volume allowed the calculation of the regurgitant fraction, which showed a correlation with invasively determined regurgitation fraction of R = 0.84 (p < 0.001). These data provide additional information that MRI may be useful as a noninvasive technique to detect and quantify mitral regurgitation.     

Observation of localized d states in metals

By application of the perturbed γ-ray distribution method combined with heavy-ion reactions and recoil implantation techniques, we have found an experimental was of producing and investigating localized 3d and 4d states in metals. 3d and 4d ions in sp metal hosts, in particular in alkali metals, exhibit the phenomena of large orbital magnetism, extremely small spin fluctuation rates, well defined ionic ground states, mixed valence, and crystal field splittings smaller than theLS coupling. These results upset long standing assumptions about the nature of d states in metals and their magnetic instabilities due to interaction of d orbitals with conduction electrons. If magnetic, the d states of 3d and 4d ions cannot be described by one electron approaches based on Anderson type models but required an analysis based on ionic configurations. The tendencies towards reduced magnetism can be well reproduced by increasing spin fluctuations which gives new insight into antiferromagnetic d-sp exchanges and the Kondo problem for d ions in sp metals. Localized ionic d states, large orbital effects, small crystal fields, and mixed valence-these new phenomena for d ions in sp metals exhibit common basic features with stable and unstable 4f and 5f systems but reflect qualitative differences to the spin dominated magnetism of 3d ions in Cu, Ag, Au and in d metal hosts.     

Determination of the Nitrogen Content of Cationic Cellulose Fibers by Analytical Pyrolysis

 Analytical pyrolysis in combination with gas chromatography and mass spectrometry or a nitrogen-phosphorus detector, respectively, were used to characterize the quaternization reagent glycidyltrimethylammonium chloride and a cationic cotton fabric. Trimethylamine was shown to be the most abundant nitrogen-containing product in the pyrolysis of glycidyltrimethylammonium chloride and was thus used for the quantification of the nitrogen content of the cationic cotton fabric. The results were compared to those obtained by traditional methods such as Kjeldahl and elemental analysis. It could be shown that pyrolysis is well suited for monitoring the nitrogen content of cellulose fibers.