Alkaloid studies XXVI. The constitution of pyrifolidine

Zusammenfassung Die Struktur desAspidosperma-Alkaloids Pyrifolidin (I) wird durch Protonresonanz und durch Vergleich mit Aspidospermin und Aspidocarpin bewiesen. Dieses Alkaloid ist in seiner absoluten Konfiguration ein Antipode des Aspidospermins.

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Paper XXV,C. Djerassi, A. A. P. G. Archer, T. George, B. Gilbert, J. N. Shoolery, andL. F. Johnson, Exper.16, 532 (1960).

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Acknowledgement. Financial support has been provided by grant H-5048 of the National Heart Institute, National Institutes of Health (U.S. Public Health Service), and by the Conselho Nacional de Pesquisas (Brazil). The postdoctorate research fellowship ofB. Gilbert in Rio de Janeiro was financed from a grant of the Rockefeller Foundation in support of a collaborative research program between Stanford University and the Instituto de Quimica Agricola, Rio de Janeiro (Brazil).     

Immobilization of chicken liver fructose 1,6-bisphosphatase on CNBr-activated Sepharose

Chicken liver fructose 1,6-bisphosphatase is readily immobilized on CNBr-activated Sepharose. The immobilization alters some enzymatic properties. They include broader pH activity curve, loss of activation by K+ or NH+4, increased resistance to inactivation by trypsin, decreased sensitivity to AMP inhibition, and loss of cooperative interaction among AMP-binding sites. The immobilized enzyme retains about 38% or 19% of the specific activity of the native enzyme when the activity is measured in the absence or presence of K+, respectively.     

Sister chromatid exchanges in human lymphocytes exposed to 8-methoxypsoralen and long wave UV radiation prior to incorporation of bromodeoxyuridine

Summary Human lymphocytes exposed to the effects of long wave UV radiation in the presence of 8-methoxypsoralen prior to stimulation by PHA show dose related sister chromatid exchanges after 2 replication cycles in vitro. This has implications for interpreting the repair processes involved and for monitoring DNA damaging agents in vivo.     

The problem of detecting a free glutamate decrease in the dorsal sensory neuron following dorsal root crush

Summary Dorsal root crush results in a highly significant decrease in the free glutamate/total free amino acid concentration ratio over an extended time period. Perhaps this is a good measurement to use in glutamate crush studies.This work was supported by Research Grant No. USPH-5-RO1-NS-10508 from the National Institutes of Health.     

The problem of the invariance of dimension in the growth of modern topology,part II

Summary This work examines the historical origins of topological dimension theory with special reference to the problem of the invariance of dimension. Part I, comprising chapters 1–4, concerns problems and ideas about dimension from ancient times to about 1900. Chapter 1 deals with ancient Greek ideas about dimension and the origins of theories of hyperspaces and higher-dimensional geometries relating to the subsequent development of dimension theory. Chapter 2 treatsCantor's surprising discovery that continua of different dimension numbers can be put into one-one correspondence and his discussion withDedekind concerning the discovery. The problem of the invariance of dimension originates with this discovery. Chapter 3 deals with the early efforts of 1878–1879 to prove the invariance of dimension. Chapter 4 sketches the rise of point set topology with reference to the problem of proving dimensional invariance and the development of dimension theory. Part II, comprising chapters 5–8, concerns the development of dimension theory during the early part of the twentieth century. Chapter 5 deals with new approaches to the concept of dimension and the problem of dimensional invariance. Chapter 6 analyses the origins ofBrouwer's interest in topology and his breakthrough to the first general proof of the invariance of dimension. Chapter 7 treatsLebesgue's ideas about dimension and the invariance problem and the dispute that arose betweenBrouwer andLebesgue which led toBrouwer's further work on topology and dimension. Chapter 8 offers glimpses of the development of dimension theory afterBrouwer, especially the development of the dimension theory ofUrysohn andMenger during the twenties. Chapter 8 ends with some concluding remarks about the entire history covered. Dedicated to Hans Freudenthal