Structure of the sequiterpene lactones fromCyclachaena xanthifolia

Conclusions The racemes ofCyclachaena xanthifolia Fresen. have yielded four sesquiterpene lactones, two of which are new, not having been described in the literature previously, and these have been called ivoxanthin and 1,2-anhydrocoronopilin. Structures II and IV have been proposed for these.The plant also contains the sesquiterpene lactones coronopilin and ambrosin.Khimiya Prirodnykh Soedinenii, Vol. 5, No. 6, pp. 487–490, 1969     

Absorption properties of commercial lead chromates

Summary The results obtained for halogen absorption with different preparations of lead chromates are discussed. It has been found that pure lead chromate is a poor external absorbent for microanalytical determinations of halogens. Differences in the absorption properties of lead chromates of various origins can be explained by the presence of PbO · PbCrO₄ and by its different mechanical structures.

---

Absorptionseigenschaften handelsüblicher Bleichromate

Zusammenfassung Die Ergebnisse der Halogenabsorption an Bleichromat verschiedener Herkunft werden diskutiert. Dabei wurde festgestellt, daß reines Bleichromat für mikroanalytische Halogenbestimmungen unzureichend ist. Unterschiedliche Absorptionseigenschaften dieser Verbindung können durch das Vorhandensein von PbO · PbCrO₄ sowie durch die verschiedene mechanische Struktur erklärt werden.

     

Opérateursp-absolument sommables surL 1 (μ)

Sans résumé     

Contributions to the analytical chemistry of osmium and ruthenium-IX: the dimercapto derivatives of asymmetric triazine as colour reagents for osmium

The parameters of the reaction of osmium with 3,5-dimercapto-6-(ethylcarboxy)-1,2,4-triazine have been studied and the optimum conditions for the spectrophotometric determination of osmium over the range 0.5-18.0 ppm determined. The coloured product contains the components in the ratio 1:2 metal:ligand.     

An uncountable family of nonorbit equivalent actions of

For each , we construct an uncountable family of free ergodic measure preserving actions of the free group on the standard probability space such that any two are nonorbit equivalent (in fact, not even stably orbit equivalent). These actions are all ``rigid' (in the sense of Popa), with the IIfactors mutually nonisomorphic (even nonstably isomorphic) and in the class