摘要:

AbstractThe proposed mechanisms by which aromatic compounds protect aliphatic materials from enhanced radiolytic decomposition are reviewed. Recent developments in this field using the radiolysis of methanol‐benzene as a typical system are discussed. Emphasis has been placed on the identification and isolation of the scavenging products from methanol‐benzene also the chemical fate of the added benzene. Isotope effects have been used to elucidate possible mechanisms of formation of the scavenging products. The application of the results of this study to the problem of self‐destruction of radioactive compounds is discussed. An interpretation of the mechanism of the protection effect in terms of the storage of labelled molecules is

ISSN:0022-2135    

DOI:10.1002/jlcr.2590030302

出版商:John Wiley&Sons, Ltd.    

年代:1967

数据来源: WILEY

摘要:

AbstractEs werden vergleichende Untersuchungen zur Aktivitätsbestimmung bei Hexachlorpropen‐(36Cl) und Trichloracrylsäure‐(36Cl) mitgeteilt. Die Messungen erfolgen im Geiger‐Müller‐Flüssigkeitszählrohr mit Zählgerät und mit einem Zweikanalflüssigkeitsszintillationsgerät. Die relativen Messfehler betragen ±0,9% beim Flüssigkeitszählrohr und ±0,6% beim Flüssigkeitsszintillationsgerät. Für die Zählrohrmessung werden Eigenabsorption der Substanz und Totzeit mit Hilfe empirischer Korrekturen eliminiert.Für Messungen mittels Flüssigkeitsszintillationsgerät wird der Löscheffekt empirisch eingeeicht. Für36Cl ist die Wirkung des Löscheffektes von Hexachlorpropen, Heptachlorpropan, Trichloracrylsäure, Äthylenglykol, Methylalkohol, Tetrachlorkohlenstoff und Tetrachloräthylen durch Verstärkungserhöhung zu kompensieren, wie experimentell gezeigt wird.Der Löscheffekt vom 4.5‐Dichlor‐1.2‐dithia‐cyclopentenon‐(3) kann aber nicht kompensiert werden. Die Wirkung von Netzspannungsschwankungen, Füllhöh

ISSN:0022-2135    

DOI:10.1002/jlcr.2590030303

出版商:John Wiley&Sons, Ltd.    

年代:1967

数据来源: WILEY

摘要:

AbstractThe deuteration and dedeuteration of 2,4,6‐trimethylpyrylium perchlorate in water (D2O and H2O, respectively) was studied by nuclear magnetic resonance using as a quantitative standard for protons tetramethylammonium bromide. γ‐Methyl groups exchange faster than α‐methyl groups; β‐standing hydrogens exchange very slowly. A mechanism involving anhydrobase and pseudobase formation is discussed and theoretical calculations are mentioned. Geminal hydrogen‐deuterium spin‐spin coupling in incompletely deuterated methyl grou

ISSN:0022-2135    

DOI:10.1002/jlcr.2590030304

出版商:John Wiley&Sons, Ltd.    

年代:1967

数据来源: WILEY

摘要:

AbstractAn automatic radio‐chromatographic method for the purification, separation and quantitative determination of chemically synthesized14C‐labelled phosphorylethanolamine is described. The chromatographic effluent from a cationic ion‐exchange resin is automatically radio‐determined by passage through a flow‐cell filled with anthracene crystals and fitted on an automatic liquid scintillation spectrometer. The principal features of the system, and the methods used for the determination of the radioactivity content are also described.The yield of the radioactive product has been calculated to be about 75%, the rapidity of the whole process satisfactory. The processing which has been described may be applied also for the synthesis, purification and separation of other chemically synthesized14C‐labelled “phospholipid phosp

ISSN:0022-2135    

DOI:10.1002/jlcr.2590030305

出版商:John Wiley&Sons, Ltd.    

年代:1967

数据来源: WILEY

摘要:

AbstractUniformly labelled D‐[14C] glucose obtained from Canna Indicaand fromChlorella was converted into several derivatives and degraded by chemical methods to yield products that separately contained carbon atoms 1, 2, 3 and 6. The specific activities of the various compounds were determined by liquid scintillation counting and from the results the pattern of labelling in carbon atoms 1, 2, 3 and 6 of the two glucose samples was obtained. The labelling was found to be uniform within the limits of experimental erro

ISSN:0022-2135    

DOI:10.1002/jlcr.2590030306

出版商:John Wiley&Sons, Ltd.    

年代:1967

数据来源: WILEY

摘要:

AbstractGlutaminsäure wurde durch Austauschreaktionen in HTO mit Tritium markiert. Bei der Austauschreaktion nach intermediärer Azlacton‐Bildung mit Essigsäure wird 1‐Glutamat racemisiert. Der Tritium‐Einbau ist gering und erfolgt nicht am C2‐Atom, wie durch enzymatischen Abbau mit Glutamat‐Dehydrogenase bewiesen wurde. Mit Hilfe von Transaminase gelingt es dagegen, spezifisch 1‐Glutaminsäure in Position 2 zu markieren und die spezifische Aktivität des eingesetzten

ISSN:0022-2135    

DOI:10.1002/jlcr.2590030307

出版商:John Wiley&Sons, Ltd.    

年代:1967

数据来源: WILEY

摘要:

AbstractThe synthesis and characterization of tritium‐labelled diphenhydramine hydrochloride is described. An attempt to label diphenhydramine directly with tritium by an exchange reaction (CH3COOH, 10 c3H2O, Pt) resulted in a mixture of tritiated benzophenone, benzhydrol, diphenhydramine, and other products. A mixture of tritiated benzophenone and benzhydrol was isolated, reduced to benzhydrol‐3H, and then condensed with dimethylaminoethanol to yield diphenhydramine‐3H with the label in the benzhydryl

ISSN:0022-2135    

DOI:10.1002/jlcr.2590030308

出版商:John Wiley&Sons, Ltd.    

年代:1967

数据来源: WILEY

摘要:

AbstractA safe, efficient and inexpensive method for preparing small quantities of tritiated water, sulfuric acid and trifluoroacetic acid is described. The preparation involves introducing the preassayed tritium sample into a carrier gas, 0.5% hydrogen in air, passing over a palladium catalyst heated to 800° C. The resulting tritiated water is gradually eluted from the catalyst and collected in suitable traps

ISSN:0022-2135    

DOI:10.1002/jlcr.2590030309

出版商:John Wiley&Sons, Ltd.    

年代:1967

数据来源: WILEY

ISSN:0022-2135    

DOI:10.1002/jlcr.2590030310

出版商:John Wiley&Sons, Ltd.    

年代:1967

数据来源: WILEY

ISSN:0022-2135    

DOI:10.1002/jlcr.2590030311

出版商:John Wiley&Sons, Ltd.    

年代:1967

数据来源: WILEY