Synthesis of a porphyrin-labelled carboranyl phosphate diester: a potential new drug for boron neutron capture therapy of cancer

A boron-rich, water-soluble porphyrin conjugate was synthesized by coupling of two carboranyl alcohols with 2-chlorophenoxyphosphorus dichloride, followed by conjugation to an amine-functionalized tetraphenyl-porphyrin via an amide linkage.     

A new class of macrocyclic complexes formed via nickel-promoted macrocyclisation of dioxime with dinitrile

o-Phthalonitrile couples with chelating dioxime on nickel(II), with formation of a dinuclear nickel(II) macrocyclic complex--the first representative of a new class of imine-appended macrocycles.     

Caminoside A,an antimicrobial glycolipid isolated from the marine sponge Caminus sphaeroconia

Extracts of the marine sponge Caminus sphaeroconia showed potent activity in a screen for bacterial type III secretion inhibitors. Bioassay guided fractionation of the extract led to the isolation of the novel antimicrobial glycolipid caminoside A (1). The structure of caminoside A was elucidated by analysis of spectroscopic data and chemical degradation.[structure: see text]     

Asymptotisches Verhalten der Maxima der Lösungen gewisser Differentialgleichungen

Eine oszillatorische Lösung u der Gleichung u" + qu = 0u' + qu = 0 hat die Wintner-Eigenschaft, wenn die relativen Maxima von q^1/4 |u|q^{1/4} |u| für t ? ￥t \to \infty gegen einen positiven endlichen Grenzwert streben. In Verallgemeinerung eines Satzes von Hartman werden neue Methoden zum Nachweis der Wintner-Eigenschaft beschrieben. Andererseits werden Funktionen q konstruiert, die belegen, daß i.a. das Verhalten von q^1/4 uq^{1/4} u fast beliebig ist. Durch Methoden aus dem Bereich der universellen Funktionen wird die Residualität solcher Funktionen q bewiesen.     

Existence theorems without convexity assumptions for optimal control problems governed by parabolic and elliptic systems

We give existence theorems for optimal control problems governed by partial differential equations. We make no convexity assumption with respect to the control variables. The results follow from a combination of the Lyapounov convexity theorem and a condition of concavity with respect to the state variable.     

Douglas algebras which are invariant under the Bourgain map

Part of this work was done while the second author was visiting the University of Georgia, Athens/Georgia, USA.     

Dynamics of oscillators with periodic dichotomous noise

The dynamics of bistable oscillators driven by periodic dichotomous noise is described. The stochastic differential equation governing the flow implies smooth trajectories between noise switching events. The dynamics of the two-branched map induced by this flow is a Markov process. Harmonic and quartic models of the bistable potential are studied in the overdamped limit. In the linear (harmonic) case the dynamics can be reduced to a stochastic one-dimensional map with two branches. The moments decay exponentially in this case, although the invariant measure may be multifractal. For strong damping, relaxation induces a cascade leading to a Cantor set and anomalous decay of the density in this case is modeled by a Markov chain. For the physically more realistic case of a quartic potential many additional features arise since the contraction factor is distance dependent. By tuning the barrier-height parameter in the quartic potential, noise-induced transition rates with the characteristics of intermittency are found.     

Hypocholesterolemic agent compactin. an alternative diels-alder strategy for the synthesis of the hexahydronaphthalene portion

The synthesis of the hexahydronaphthalene segment (4) of compactin (1) has been accomplished in a short sequence (8 steps from 9) featuring the intramolecular Diels-Alder cycloaddition of 7b.