Transformations microbiologiques-3 : Approche de la topologie du site hydroxylant de beauveria sulfurescens

Hydroxylation of some bi- or tricyclic amides or lactams, the determination of the absolute configuration of the alcohols obtained and the topology of the hydroxylating site of Beauveria sulfurescens based on these absolute configurations, are discussed.     

A numerical study of the problem of diffraction at a locally deformed plane wave-guide

We present a rigorous solution for the problem of diffraction at a locally deformed plane wave-guide. This method can be applied to the study of mode coupling and mode conversion.     

Implications of enzymatic, acidic and thermal hydrolysis of DNA on the occurrence of cross-linked melphalan DNA adducts

Calf thymus DNA was treated with melphalan, a nitrogen mustard, and the formation of melphalan cross-linked DNA adducts was investigated. These cross-linked adducts could not be detected either in the enzymatically or in the thermally generated DNA hydrolysates. However, a search for DNA cross-linked adducts in the hydrolysates obtained under acidic conditions revealed the presence of different types of cross-links, mainly containing an adenine moiety. These results are very important because they show that the detection of cross-links is dependent on the hydrolytic procedure used and that these cross-linked adducts are formed under totally different reaction conditions from those in in vivo situations. This can explain the very low abundance or even the absence of cross-linked adducts in nitrogen mustard treated animals. The generally accepted theory that the anti-cancer activity of bifunctional mustards such as melphalan is due to cross-linking of DNA strands remains therefore from our point of view questionable.     

Mesure des vecteurs sur un groupeG et corps ternairesG-mesurables

Sans résuméCet article recouvre la deuxième partie d'une thèse de doctor d'Etat [7].     

The type and extent of non-LTE in argon arcs at 0.1-10 bar

A 30-A, 3-mm-diameter, wall-stabilized argon arc with 1% hydrogen is examined spectrometrically at pressures of 0.1-10 bar. Values of T_g, and T_exa diverge as pressure decreases below 5 bar (n_e⩽1×10¹⁷ cm^-3) at r=0. T_exβ is 20-40% larger than the other temperatures. The results are dependent on the transition probability scale used     

Straightforward three-component palladium-catalysed synthesis of pyridazin-3(2H)-one libraries

A simple and straightforward three-component methodology for the solution phase high-throughput synthesis of 2,5-disubstituted pyridazin-3(2H)-one libraries has been developed. The diversity at position 5 of the heterocycle is determined by the use of Suzuki, Sonogashira, Heck or Stille coupling.