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Walter Renold Regula Nf-Müller Urs Keller Bruno Willhalm Günther Ohloff 《Helvetica chimica acta》1974,57(5):1301-1308
A total of 68 constitutents, mainly aldehydes, ketones and esters, have been identified for the first time in a black tea aroma concentrate using coupled gas-chromatography/mass spectrometry. 相似文献
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B. Dauth P. Sen B. Rupp W. Gudat Ch. Ziegler W. Göpel 《Zeitschrift für Physik B Condensed Matter》1990,79(2):169-172
We present X-ray photoemission spectroscopy (XPS) results obtained on polycrystalline YBa2Cu3O7–x
in the non-metallic (x>0.6) and metallic state (x<0.6) by an in-situ oxygen deloading/loading procedure, thus avoiding uncontrolled surface contaminations. The transition to the metallic (superconducting) state is characterized by corresponding changes in the O1s and Cu2p photoelectron lineshapes being in accordance with charge transfer from CuO2 planes to CuO chains. In particular, a peak at 531.1 eV binding energy is related to the presence of oxygen hole states (O–). 相似文献
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E. Rupp Ph. Nöll L. Krauss F. Lehmann W. F. Schirmer M. de Jong Umberto Saporetti Enrico Rimini Paola Fiora und Albert Fernau 《Fresenius' Journal of Analytical Chemistry》1909,48(7-8):506-514
Ohne Zusammenfassung 相似文献
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Impact of the sublinear photoconductivity law on the interpretation of holographic results in BaTiO3
R. A. Rupp A. Maillard J. Walter 《Applied Physics A: Materials Science & Processing》1989,49(3):259-268
Thick holographic refractive index gratings are written in nominally pure and in iron doped BaTiO3 crystals. The phase shift between refractive index grating and light pattern is studied as a function of an externally applied electric field by a direct phase shift measuring technique. The choice of the method is suggested by a theoretical analysis which allows for the effect of a nonlinear relation between photoconductivity and light intensity on the holographic writing process. 相似文献
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Simone Portmann Hiu Ying Kwan Regula Theurillat Andrea Schmitz Meike Mevissen Wolfgang Thormann 《Journal of chromatography. A》2010,1217(51):7942-7948
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. 相似文献