A fungitoxic principle from the leaves ofLawsonia inermis Lam.

Summary During antifungal screening of higher plants, the leaves ofLawsonia inermis were found to exhibit strong fungitoxicity. On chemical investigation, the antifungal factor was found to be 2-hydroxy-1,4-naphthoquinone (Lawsone). The minimum effective dose against test organism was found to be 1000 ppm. Lawsone was found to exhibit fungicidal activity, wide fungitoxic spectrum and nonphytotoxicity.Acknowledgment. Authors are thankful to Dr Nitya Nand, Central Drug Research Institute, Lucknow, for providing facilities to carry out chemical investigations. Our thanks are particularly due to Dr R. S. Kapil, Dr Geeta Devi Tripathi and Dr S. C. Tripathi for their help rendered in various ways.     

A partial elucidation of the gauge principle

The elucidation of the gauge principle “is the most pressing problem in current philosophy of physics” said Michael Redhead in 2003. This paper argues for two points that contribute to this elucidation in the context of Yang–Mills theories. (1) Yang–Mills theories, including quantum electrodynamics, form a class. They should be interpreted together. To focus on electrodynamics is potentially misleading. (2) The essential role of gauge and BRST symmetries is to provide a local field theory that can be quantized and would be equivalent to the quantization of the non-local reduced theory. If this is correct, the gauge symmetry is significant, not so much because it implies ontological consequences, but because it allows us to quantize theories that we would not be able to quantize otherwise. Thus, in the context of Yang–Mills theories, it is essentially a pragmatic principle. This does not seem to be the case for the gauge symmetry in general relativity.     

Chemical investigations ofAlangium lamarckii II. Isolation of choline from the leaves

Zusammenfassung Nachweis des Cholinchlorid als Substanz, welche für die cholinergische Wirkung wässriger Extrakte der Blätter vonAlangium lamarckii verantwortlich ist.     

Isolation of (−)-cryptosporiopsin,a chlorinated cyclopentenone fungitoxic metabolite fromPhialophora asteris f. sp.helianthi

Summary The (–)-enantiomer of cryptosporiopsin, a chlorinated cyclopentenone fungitoxic metabolite, was isolated fromPhialophora asteris f. sp.helianthi. Next to a comparable fungitoxic activity as shown by crypstosporiopsin, the product particularly inhibits growth ofSclerotinia sclerotiorum, an important pathogen on sunflower. Two further metabolites were tentatively identified as a stereoisomer of cryptosporiopsin and its dehydrated derivative.The authors are much indebted to Dr.G. M. Strunz (Canadian Forestry Service) for valuable suggestions and the generous gift of cryptosporiopsin and to the University of Utrecht for the part-time fellowship to one of us (Y.T.) given.     

Isolation of a pharmacologically active principle from ehrlich carcinoma tumor cells

Résumé Les propriétés biologiques d'une nouvelle substance pharmacologique active isolée des cellules de l'ascite d'Ehrlich sont décrites en détail. La substance isolée contracte in vitro l'iléum du cobaye ou l'utérus du rat et relaxe l'ileum de la souris. In vivo, cette substance possède un effet hypotensif chez le chat.     

Chemical investigations ofAlangium lamarckii III. Isolation of steroids and terpenoids from the leaves

Zusammenfassung Es wird über die Isolierung und Charakterisierung von Inhaltsstoffen, vermutlich Steroide, aus einer indischen Pflanzenart,Alangium lamarckii, berichtet. Medizinische Zubereitungen aus dieser Pflanze werden für verschiedene Indikationen, z.B. auch antiinflammatorische, verwendet.     

A similarity-based approach of Kuhn’s no-overlap principle and anomalies

In their book Cognitive Structure of Scientific Revolutions, Hanne Andersen, Peter Barker, and Xiang Chen reconstruct Kuhn’s account of conceptual structure and change, based on the dynamic frame model. I argue against their reconstruction of anomalies and of the no-overlap principle and propose a competing model, based on the similarity relation. First, I introduce the concept of psychological distance between objects, and then I show that the conceptual structure of a theory consists of a set of natural families, separated by a significant empty space. I argue that, in such a conceptual structure, the ES condition, according to which the distance between natural families should be greater than the distance between any two objects belonging to the same natural family, is satisfied. Anomalous objects lead to the violation of this condition. I argue that in a conceptual structure satisfying the ES condition, a similarity relation could be defined, so that natural families would be similarity classes, satisfying the no-overlap principle. In a structure not satisfying this principle, such similarity classes could not be delimited.     

On the history of the principle of least squares

Communicated by C. Truesdell     

Correspondence principle versus Planck-type theory of the atom

This article examines the problem of the origins of the correspondence principle formulated by Bohr in 1920 and intends to test the correctness of the argument that the essential elements of that principle were already present in the 1913 “trilogy”. In contrast to this point of view, moreover widely shared in the literature, this article argues that it is possible to find a connection between the formulation of the correspondence principle and the assessment that led Bohr to abandon the search for a Planck-type theory. In fact, a thorough examination of Bohr’s works shows that the birth of this principle coincided with the depletion of a research program whose origins may date back to Bohr’s stay at the Rutherford’s laboratory (summer 1912). Finally, this article argues that original program of research was abandoned when it became clear that Planck’s quantum hypothesis for the harmonic oscillator was not an adequate support for the theoretical architecture of atomic physics; namely, there was evidence enough to justify a most drastic conclusion, according to Bohr: “I do not think that a theory of the Planck type can be made logical consistent”.