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A Borner

Publications and source records attributed to A Borner.

4 recordsLinked to original sources
PubMed2000

Stereoisomerism in bridged octahedral dimeric complexes with tetradentate ligands. Diastereospecific formation of syn-delta delta-(cis-beta-L)TiO2 (L-chiral salen type ligands)

The first two examples of the successful application of chiral salen ligands for diastereoselective syntheses of dinuclear Ti(IV), (L1Ti)2O2 and (PdI2L2Ti)2O2 species with defined chirality and geometry at the metal centre are presented. The structure of the complexes was established by X-ray structural analysis. Both complexes have similar structural features: (1) chiral salen ligands have cis-beta configuration around Ti centres, (2) (R,R) chirality of ligands induces delta helicity of ligand, and (3) syn arrangement of ligand donor atoms in relation to the TiO2Ti plane. Stereoselective effects of the dimers are discussed engaging available literature data. A model has been proposed to rationalise high syn selectivity in the formation of dimers.

Journal Article↗
PubMed1999

Chromosomal location and genetic mapping of the mismatch repair gene homologs MSH2, MSH3, and MSH6 in rye and wheat

The efficiency of homeologous recombination is influenced by mismatch repair genes in bacteria, yeast, and mammals. To elucidate a possible role of these genes in homeologous pairing and cross-compatibility in plants, gene probes of wheat (Triticum aestivum) specific for the mismatch repair gene homologues MSH2, MSH3, and MSH6 were used to map them to their genomic positions in rye (Secale cereale). Whereas MSH2 was mapped to the short arm of chromosome 1R, MSH3 was mapped to the long arm of chromosome 2R and MSH6 to the long arm of chromosome 5R. Southern blots with nullisomic-tetrasomic (NT) lines of wheat indicated the presence of the sequences on the respective homeologous group of wheat chromosomes. Additionally, an MSH6-specific homologue could also be detected on homoeologous group 3 of wheat. However, in the well-known, highly homoeologous pairing wheat mutant ph1b the MSH6-specific sequence is not within the deleted part of chromosome 5BL, indicating that the pairing phenotype is not due to a loss of one of the mismatch repair genes tested.

Journal Article↗
PubMed1999

[In Process Citation]

OBJECTIVE: We examined the placental transfer of the calcium antagonists Flunarizine and Verapamil and their effects on the placental metabolism using the dual in vitro perfusion of the human placental lobulus. MATERIAL AND METHODS: Eight placental lobuli were perfused with either 10 micrograms/ml Flunarizine or Verapamil over 6 hours. Two perfusions without any substrate were used as control. RESULTS: The transfer of the control substances antipyrin and kreatinin was not affected by the perfusion with the calcium antagonists. Flunarizine and Verapamil crossed quickly the placental wall, but most of them were accumulated in the perfused placental tissue. Verapamil had a greater placental transfer than Flunarizine. The placental glucose consumption as well as the lactate production were not changed by both of the calcium antagonists. Flunarizine and Verapamil stimulated the placental beta HCG synthesis into the maternal circulation.

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