Universal Extension and Excision for Topological Algebras

We construct a topology on the tensor algebra that makes the multiplication jointly continuous and is universal for algebras with jointly continuous multiplication. This result, together with the methods developed by Cuntz for m-algebras are used to prove the excision theorem of Cuntz and Quillen in the more general case of c-algebras.     

Simultaneous Quantification of Neomycin and Bacitracin by LC-ELSD

The first simultaneous quantification of neomycin and bacitracin using liquid chromatography evaporative light scattering detection as an alternative to MS detection and pre-/post-column derivatisation, respectively, was the aim of this study. The developed method was validated for two strength of neomycin and one strength of bacitracin in sterile pharmaceutical formulation and is a fast and efficient tool for content uniformity tests in quality control. With this method the separation of neomycin from sulfate and the base line separation of the four major components of bacitracin (bacitracin A, B1, B2 and B3) was achieved. These four components are responsible for 96% of the microbiological activity. A Phenomenex Synergi POLAR analytical column (250 mm × 4.6 mm, 4 μm I.D.) in combination with 0.5% perfluoropropionic acid and acetonitrile in gradient mode, the peaks of interest could be separated with high efficiency within 14 min. The calibration was performed using a second order regression with an R ² = 0.9999 for neomycin (B and C) sulfate and R ² = 0.9996 for bacitracin A, B1, B2 and B3. The results of the accuracy evaluation were 99.2 and 99.7%, respectively, for neomycin and 100.8% for bacitracin. Injection precision results are 0.4–1.5 RSD% recorded for six injections. The established method has a high potential for routine high-throughput analyses in the pharmaceutical industry.     

3D-snapshot flash NMR imaging of the human heart

SNAPSHOT-FLASH is a recently developed, ultrafast imaging technique, based on conventional FLASH imaging. The application of this new variant to 3D imaging allows the acquisition of a 128 x 128 x 32 data set in 12.5 seconds without triggering, or for cardiac imaging with gating within 32 heartbeats. Compared to standard 3D-FLASH this is 128 times faster, because triggering is only required when the 3D phase-encoding gradient is incremented. The method depicts for the first time fast three-dimensional views of the human heart without motional artifacts. The images are spin-density weighted. Using suitable prepulses any desired T1- or T2-contrast may be achieved. The generation of 3D movies is possible without an increase of the total scan time.     

Korrosion von Werkstoffen

Ohne Zusammenfassung