High-performance liquid chromatography and capillary supercritical-fluid chromatography separation of vegetable carotenoids and carotenoid isomers

Carotenoids from carrots and tomatoes were separated with high-performance liquid chromatography (HPLC) and capillary supercritical fluid chromatography (SFC). All trans alpha- and beta-carotene were separated from their respective cis-isomers with capillary SFC. Carotenoids extracted from tomatoes included xanthophyll, lycopene and beta-carotene, while alpha- and beta-carotene were extracted from carrots. The HPLC separations were accomplished isocratically with a 25-cm column containing 5-microns ODS and methanol-acetonitrile-chloroform (47:47:6) or acetonitrile-dichloromethane (80:20). beta-Carotene cis-isomers were separated with SFC with a SB-cyanopropyl-25-polymethylsiloxane column, while alpha-carotene isomers were separated with two SB-cyanopropyl-50-polymethylsiloxane columns. Carotenoids from carrots and tomatoes were separated with a SB-phenyl-50-polymethylsiloxane column. Carbon dioxide with 1% ethanol was the SFC mobile phase. The eluent was monitored at 461 nm for HPLC and either 453 or 461 nm for SFC.     

Beckmann-Umlagerung und Fragmentierung,III. Teil Versuche zur 7-Zentren-Fragmentierung eines γ-Aminoketoxims: Fragmentierungsreaktionen, 20. Mitteilung

In aqueous dioxane the p-toluenesulfonate 11B of 1β-dimethylamino-5-oximino-trans-decalin (11a) undergoes almost quantitative Beckmann rearrangement to the lactam 23. Approx. 1%, only, of the product of so-called 7-centre fragmentation, i.e. trans-9-cyano-non-5-enal (14) is detectable. Furthermore, the picryl ether 11C of the oxime 11a reacts at a normal rate. The results confirm the conclusion reached earlier, namely that fragmentation cannot compete with the Beckmann rearrangement in the case of γ-amino ketoximes, in contrast to the behaviour of α-amino ketoximes.     

Operator algebras and a theorem of Dieudonne

LetA be aC*-algebra with second dualA″. Let (φ _n)(n=1,...) be a sequence in the dual ofA such that limφ _n(a) exists for eacha εA. In general, this does not imply that limφ _n(x) exists for eachx εA″. But if limφ _n(p) exists whenever p is the range projection of a positive self-adjoint element of the unit ball ofA, then it is shown that limφ _n(x) does exist for eachx inA″. This is a non-commutative generalisation of a celebrated theorem of Dieudonné. A new proof of Dieudonné’s theorem, for positive measures, is given here. The proof of the main result makes use of Dieudonné’s original theorem.     

Nitrate esters as nitric oxide donors: SS-nitrates

[structure: see text]. The important biological secondary messenger NO can be generated from exogenous nitrovasodilators and NO donors. Nitrate esters are nitrovasodilators and NO mimetics, believed to be biotransformed to NO in vivo. On the basis of a mechanistic hypothesis, nitrates have been synthesized that release NO at significant rates in neutral aqueous solution in the presence only of added thiol. The novel masked beta-mercaptonitrates reported (SS-nitrates), provide information on possible sulfhydryl-dependent biotransformation mechanisms for nitrates in clinical use.     

Classical mechanics in Galilean space-time

Galilean space-time plays the same role in nonrelativistic physics that Minkowski space-time does in relativistic physics. In this paper, the fundamental concepts (velocity, momentum, kinetic energy, etc.) and principles (laws of motion and conservation laws) of classical physics are formulated in the language of Galilean space-time. Much of the development closely parallels the development of similar concepts and principles in the theory of special relativity.     

Quantum mechanics in Galilean space-time

The usual quantum mechanical treatment of a Schrödinger particle is translated into manifestly Galilean-invariant language, primarily through the use of Wigner-distribution methods. The hydrodynamical formulation of quantum mechanics is derived directly from the Wigner-distribution formulation, and the two formulations are compared. Wigner distributions are characterized directly, i.e., without reference to wave functions, and a heuristic interpretation of Wigner distributions and their evolution is developed.