Experiences with synthetic aperture focusing technique in the field

The detection and evaluation of defects in industrial components relies strongly on ultrasonic inspection techniques. Distance gain size (DG) or reference reflector methods can be improved concerning their localization, signal-to-noise ratio and sizing accuracy by the synthetic aperture focusing technique (SAFT). To obtain a high quality image, parameters like focal probe versus contact technique probe, achieved resolution or features of SAFT images compared with B-scan images are discussed. The implementation of SAFT in a CAD environment allows us to present stacked 2D reconstructions dynamically. On a cladded testblock with half-penny shaped cracks the advantage of combining CAD with SAFT is shown. A 3D SAFT example finalizes the overview of two decades of experience in applying this technique.     

Die Gehaltsbestimmung von Spiessglanz und Goldschwefel

Ohne Zusammenfassung     

A measurement of the proton structure functions from neutrino-hydrogen and antineutrino-hydrogen charged-current interactions

Within the framework of the quark-parton model, the quark and anti-quark structure functions of the proton have been measured by fitting them to the distributions of the events in the Bjorkeny variable. The data used form the largest sample of neutrino and antineutrino interactions on a pure hydrogen target available, and come from exposures of BEBC to the CERN wide band neutrino and antineutrino beams. It is found that the ratiod _v /u _v of valence quark distributions falls with increasing Bjorkenx. In the context of the quark-parton model the results constrain the isospin composition of the accompanying diquark system. Models involving scattering from diquarks are in disagreement with the data.     

Zur quantitativen Bestimmung des Kaliums

Ohne Zusammenfassung     

Zur Kristallchemie einiger Alkalithiomanganate und-zinkate. Mit einer Bemerkung zum ThCr2Si2-Typ

On the Crystal Chemistry of Some Alkali Thiomanganates and -zincates. With a Remark on the ThCr₂Si₂-Type New quaternary sulfides ALiMS₂ (A ? K, Rb, Cs and M ? Mn, Zn) were synthesized by a reaction of alkali carbonates with manganese and zinc, respectively, in a stream of H₂S at 800°C. Single crystal X-ray investigations revealed the structures of KLiMnS₂ and KLiZnS₂. All compounds are isotypic and crystallize in the BaZn₂P₂-structure type. The atomic arrangements are treated as nine spheres close packings of sulfur atoms filled with cations. Criteria are given to distinguish the BaZn₂P₂-structure type from the ThCr₂Si₂-structure type.     

Enantioselective capillary electrophoresis for identification and characterization of human cytochrome P450 enzymes which metabolize ketamine and norketamine in vitro

Ketamine, a phencyclidine derivative, is used for induction of anesthesia, as an anesthetic drug for short term surgical interventions and in subanesthetic doses for postoperative pain relief. Ketamine undergoes extensive hepatic first-pass metabolism. Enantioselective capillary electrophoresis with multiple isomer sulfated β-cyclodextrin as chiral selector was used to identify cytochrome P450 enzymes involved in hepatic ketamine and norketamine biotransformation in vitro. The N-demethylation of ketamine to norketamine and subsequently the biotransformation of norketamine to other metabolites were studied via analysis of alkaline extracts of in vitro incubations of racemic ketamine and racemic norketamine with nine recombinantly expressed human cytochrome P450 enzymes and human liver microsomes. Norketamine was formed by CYP3A4, CYP2C19, CYP2B6, CYP2A6, CYP2D6 and CYP2C9, whereas CYP2B6 and CYP2A6 were identified to be the only enzymes which enable the hydroxylation of norketamine. The latter two enzymes produced metabolic patterns similar to those found in incubations with human liver microsomes. The kinetic data of ketamine N-demethylation with CYP3A4 and CYP2B6 were best described with the Michaelis–Menten model and the Hill equation, respectively. This is the first study elucidating the individual enzymes responsible for hydroxylation of norketamine. The obtained data suggest that in vitro biotransformation of ketamine and norketamine is stereoselective.