Die Algebra der Babylonier

Ohne Zusammenfassung Vorgelegt von B. L. van der Waerden     

Die Biochemie der Chinone

Ohne Zusammenfassung     

Die Konstitution der Salamander-Alkaloide

Summary Four alkaloids have been isolated from the skin gland of the Feuer- and Alpensalamander (Salamandra maculosa andatra Laur.). The structure, stereochemistry and absolute configuration of the principal alkaloid, samandarin, have been elucidated by chemical, optical, and X-ray-crystallographic methods. The basic structure of samandarin is derived from 5-androstan by the insertion between C-2 and C-3 of ring A of an NH group which, along with an oxygen bridge between C-1 and C-3, constitutes an oxazolidine ring; at C₁₆ there is a-hydroxyl group. By virtue of its origin and constitution samandarin occupies a unique position among alkaloids.

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Nach der am 15. Juni 1960 in der Aula der Universität Zürich gehaltenen zweitenPaul-Karrer-Vorlesung. Der Vortrag ist zum Teil gekürzt, Ergebnisse der letzten Zeit sind in die vorliegende Fassung eingearbeitet worden.     

Die Rouleau-Bildung der Rindererythrocyten

Summary Not a trace of rouleau formation could be observed with native beef erythrocytes under varying conditions. A typical rouleau formation and a markedly increased sedimentation rate could, however, be elicited when the surface layer of the beef erythrocytes was carefully removed with proteolytic enzymes. This is an additional evidence that the beef erythrocytes are enveloped in a surface sheet, which inhibits their hemagglutination and their rouleau formation. Papain is a proteolytic enzyme, which is inactive regarding rouleau formation. Lysolecithin disintegrates the rouleaus, albumin restores them.

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Diese Arbeit wurde von der H.-Buss-Stiftung (Basel) unterstützt.     

Die radiofrequente Strahlung der Sonnenkorona

Summary From the theory of the free-free-transitions of the electrons in the solar corona the absorption coefficient and optical thickness of the corona are calculated. From these the intensity of the coronal radiation at radio-frequencies is deduced for different distances from the centre of the sun's disc (Fig. 1). In fig. 2 the spectral intensity-distribution is given for radiation coming from the sun's centre (=0), from the sun's limb (=1), and from a point one solar radius outside the sun's limb.     

Die Welt der kleinen Planeten

Summary After a historical survey on the discovery of the small planets and the international organization of the calculation of orbits the importance of the divergences from the ordinary orbits between Mars and Jupiter is discussed. On the one side those small planets which approach Mars, Jupiter, even Earth and Saturn, in strongly excentric orbits offer new methods for the mass determination of the large planets; e.g. the perigee of Eros made possible a new determination of the parallax of the sun (8,79). On the other side the group of the Trojans e.g. gives new aspects for the problem of the three bodies. In the breaches of commensurability the statistical distribution of the orbits of the small planets hints to the problem of the stability of the planetary system.     

Die biologische Bedeutung der Vitamine

Summary The vital importance of the vitamins resides in theircoferment function, which enables them to catalyse enzymatic processes in living tissues. The term coferment is used in this connection to designate organic compounds of relatively low molecular weight, which in conjunction with the specific proteinous apoferments bring about the transformation of definite substrates. The vitamins are, however, catabolized like ordinary substrates when they come into contact with enzymatic systems in which they have no coferment function. This explains why normal life cannot be sustained, if the living organisms do not receive asnutritional factors the vitamins which they cannot synthesize. From a biochemical point of view not only exogenous hypo- or avitaminoses but all pathological changes may be regarded as the sequelae of disturbances in one or several enzymatic systems. The vitamins may exert a regulating influence also in these enzymatic disturbances which are not directly caused by vitamin deficiency. In such cases they will act asrèmedies.     

Die Natur der anorganischen Knochensubstanz

Résumé Nous rapportant à nos recherches de ces dernières années relatives à la calcification et à la substance inorganique des os, nous rendons attentifs au fait que les arguments avancés parBrasseur etDallemagne ne sont pas convainquants; ils ne sont pas suffisants pour faire abandonner les vues proposées parBredig, Klement et autres, confirmées par nous, sur la constitution de la substance inorganique des os. A notre avis, il n'y a jusqu'ici aucune raison d'abandonner ces conclusions d'après lesquelles la substance inorganique des os est constituée en plus grande partie par de l'apatite: Ca₅(PO₄)₃(OH).

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Bemerkungen zu:M. J. Dallemagne undH. Brasseur, Exper.3, 469 (1947).     

Die Treffermethode in der Messung der Parathyreozyten-Aktivität nach der Epiphysektomie

Résumé Par l'application de la méthode d'intégration aux points sur les clichés électronomicroscopiques, on a constaté l'hypertrophie des organelles cellulaires (mitochondries, le réticulum endoplasmique et l'appareil de Golgi) dans les cellules parathyroïdiennes de rats sacrifiés trois semaines après l'épiphysectomie.     

Die Alkaloide im Stoffwechsel der Pflanze

Ohne Zusammenfassung10. Paul-Karrer-Vorlesung, gehalten am 19. Juni 1968 in der Aula der Universität Zürich.     

Die Beeinflussung der Mitose durch Urethan

Summary 2% aqueous solution of urethan causes after 6–10 hours' action on root types ofVicia faba andAllium cepa a shortening of chromosomes, it stops also the metaphase and lowers the rate of mitosis. Probably there is a connection between the lipophile groups, the reduction in surface tension, and the diminution of chromosomes. Dioxan with similar physical properties has the same effect.     

Die schweizerische Akademie der medizinischen Wissenschaften

Ohne Zusammenfassung     

Die Beeinflussung der Leukozytenphagozytose mit Phlorrhizin

Summary In the rat the intraperitoneally administered phlorrhizin significantly reduces the phagocytosis of bacteria by leucocytes, as determined by thePlatonow-Ludány-Vajda method, with the mean decrease being — 33.5%. The effect is reversible. The phenomenon appears to be due to an alteration of carbohydrate metabolism in the leucocytes. The experiments supply new evidence supporting the view that alongside biophysical factors (surface effects) also cellular metabolic processes may play important roles in the phagocytotic activity of leucocytes.     

Die Reizschwelle der Sinnesorgane als physikalisches Problem

Summary A survey is given of recent work on physical aspects of sensory processes. The reasoning which leads to the generally recognized view that one rod of the retina is excited by only one quantum of light is given in par. II. In par. IIIa summary is given of the papers byHecht andVan der Velden on the number of rods which must be struck in order to obtaina sensation of light. Par. III describes the role of the quantum character of light at higher intensities (de Vries), where it sets a limit to intensity discrimination and visual acuity. The influence of Brownian movement on the process of hearing is discussed in par. VI. It is found that the Brownian movement of the inner ear is close to the threshold actually observed (de Vries), whereas the Brownian motion of the air at the eardrum (seeSivian andWhite) is below the audible threshold. The role of the Brownian movementin the sense cells is described in par. VII; the results are used for an analysis of the mechanism of hearing (see alsode Vries); evidence is obtained that electric voltages are generated in the tectorial membrane (the well-known cochlear microphonics) and that they play an important part in the mechanism of energy transfer to the sense cells (similar voltages were also derived from the cupolæ in the lateral lines of fishes by the present author). Finally some physical arguments are sumarized againstYeagley's theory of bird navigation.     

Die modernen Methoden und Ergebnisse der Geophysik

Ohne Zusammenfassung     

Die Serumphosphatasen der Ratte in verschiedenen Lebensaltern

Summary The serum alkaline and acid phosphatases were examined in male rats between the ages of 20 and 300 days, using the method ofHuggins andTalalay ⁴. The activities of acid and alkaline phosphatases increase significantly to the age of 45 days, followed by a highly significant decrease up to 120th day for alkaline and to 75th day for acid phosphatase. After castration, highly significant increases in the acid, but no changes in the alkaline serum phosphatase were observed.     

Die Entwicklung der Valenzlehre und Alfred Werner

Summary Surveying the various concepts of valency which have been put forward sinceDalton for the classification of chemical phenomena, it is found that the principles have been either dualistic (Berzelius, Blomstrand, Arrhenius, Kossel) or unitarian (Gerhard, Couper, Kekulé). The phenomena of inorganic chemistry can be classified only by using dualistic concepts, whereas unitarian systems proved to be superior for the phenomena of organic chemistry. In the conceptions of G. N.Lewis and N.Sidgwick, a combination of dualistic and unitarian concepts in one theory was achieved by distinguishing two types of bonds (mobile-immobile, polar-non-polar, ioniccovalent). With the octet rule, ions as well as molecules (uncharged and charged) may be derived and it is readily understood that bonds may vary from extreme polarity to non-polar links.The coordination theory ofWerner neither fits into the dualistic nor the unitarian class of valency principles.Werner derives the compounds by using principal and auxiliary valencies (Haupt- und Nebenvalenzen) and distinguishes addition and insertion compounds (Anlagerungs- und Einlagerungsverbindungen). However, he avoids making any statement concerning the nature of the bonds, which makes his system very adaptable but difficult to grasp. Today it is readily understood thatWerner's principal valency characterizes the stoichiometry and his coordination number characterizes the structure of the compound in question without making any statement about the nature of the bonds involved. Because of thatWerner's concepts have survived and are indispensable even today, in spite of the rise of atomic physics which has changed our views on the nature of the chemical bonds so drastically.

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Paul-Karrer-Vorlesung, gehalten am 22. Juni 1966 zum Anlass der hundertsten Wiederkehr des Geburtstages vonAlfred Werner, dem Vorgänger von Professor Karrer auf dem Lehrstuhl für Allgemeine Chemie der Universität Zürich.