Analytisch-chemische Bestimmung nichtradioaktiver Stoffe mit einem Flüssig-Szintillationsspektrometer durch Radiolumineszenz und Absorptionsphotometrie im Čerenkov-Licht

Summary Three techniques are described which allow a quantitative chemical determination of non-radioactive substances by the means of a liquid scintillation counter. The first method is based on the chemical quenching of a radioluminescent solution through the substance that is to be determined. The second method may be described as absorption photometry in erenkov-light and the third one as absorption photometry in radiofluorescence light.     

Stereospecificity of allantoin degradation inStreptococcus allantoicus

Zusammenfassung Die Stereospezifität der Enzyme des Allantoinabbaus inStreptococcus allantoicus und die optische Drehung der Reaktionsprodukte wurde bestimmt. Allantoinase war aspezifisch, während Allantoate-amidohydrolase ausschliesslich (-)-Ureidoglykolate bildete. Diese Substanz wurde durch (-)-Ureidoglykolase hydrolysiert.     

Kompensation der teratogenen Wirkung eines Thalidomid-Metaboliten durchl-Glutaminsäure

Summary Skeletal defects were observed in the off-spring of SWS-mice following i.p. administration of phthaloyl-l-glutamic acid, a metabolite of thalidomide. The fetuses of animals which receivedl-glutamic acid in addition to the teratogenic drug, did not show any malformations, whereas concurrent i.p. administration of thed-isomer of glutamic acid failed to reverse teratogenicity induced by phthaloyl-l-glutamic acid.     

Effect of aluminium phosphate gel on whole-body retention of simultaneously administered226Ra,85Sr and47Ca in mice

Résumé L'administration presque simultanée d'un gel de phosphate d'alumine et de²²⁶RaCl₂ réduit de 800 fois l'absorption intestinale du²²⁶Ra chez la souris. La charge corporelle en⁸⁵Sr et⁴⁷Ca est réduite d'environ 10 resp. 3 fois.     

Migration of lymphocytes through the endothelium of venules in experimental allergic neuritis

Zusammenfassung Bei der experimentellen allergischen Neuritis verlassen die Lymphozyten das zirkulierende Blut der Venolen der peripheren Nerven, indem sie eher durch die als zwischen den Endothelzellen austreten. Der Durchtritt durch das Zytoplasma der Endothelzellen ist ein Beispiel von Emperipolesis.

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Supported by parts by NIH grant No. NB-03789-05, Inst. grant No. FRO5486-04, and a grant from the Swedish Medical Research Council. I thank Mr.L. Cherkas for help with the photography.     

Demonstration of two ATPases in human erythrocyte membranes

Zusammenfassung Menschliche Erythrozytenmembranen enthalten eine NEM-sensitive und eine NEM-insensitive ATPase, die wahrscheinlich beide an Membranoberflächen lokalisiert sind.

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These studies were carried out with the generous support of the Deutsche Forschungsgemeinschaft.     

Suppression of immunization to tuberculosis and diphtheria by an extract of lymphoid tissue

Zusammenfassung Dank einer neuen Anwendung von Lymphknotenextrakten (statt Röntgenextrakten, Corticosteroiden, Antilymphozytenserum usw.) wird eine erhebliche Reduktion der immunologischen Reaktion erzielt, wenn die Tiere mit diesen Extrakten vorbehandelt und gleichzeitig mit Antigenen behandelt werden.

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This investigation was supported in part by U.S.P.H.S. Research Grant No. CA-02624 from National Cancer Institute; and in part by an institutional grant to Detroit Institute of Cancer Research from United Foundation of greater Detroit allocated through Michigan Cancer Foundation and the Detroit General Hospital Research Corporation, and Newaygo County Cancer Society.     

Granular physics: creating a dry variety of quicksand

Sand can normally support a weight by relying on internal force chains. Here we weaken this force-chain structure in very fine sand by allowing air to flow through it: we find that the sand can then no longer support weight, even when the air is turned off and the bed has settled--a ball sinks into the sand to a depth of about five diameters. The final depth of the ball scales linearly with its mass and, above a threshold mass, a jet is formed that shoots sand violently into the air.     

The building blocks of planets within the 'terrestrial' region of protoplanetary disks

Our Solar System was formed from a cloud of gas and dust. Most of the dust mass is contained in amorphous silicates, yet crystalline silicates are abundant throughout the Solar System, reflecting the thermal and chemical alteration of solids during planet formation. (Even primitive bodies such as comets contain crystalline silicates.) Little is known about the evolution of the dust that forms Earth-like planets. Here we report spatially resolved detections and compositional analyses of these building blocks in the innermost two astronomical units of three proto-planetary disks. We find the dust in these regions to be highly crystallized, more so than any other dust observed in young stars until now. In addition, the outer region of one star has equal amounts of pyroxene and olivine, whereas the inner regions are dominated by olivine. The spectral shape of the inner-disk spectra shows surprising similarity with Solar System comets. Radial-mixing models naturally explain this resemblance as well as the gradient in chemical composition. Our observations imply that silicates crystallize before any terrestrial planets are formed, consistent with the composition of meteorites in the Solar System.