Despite these concerns, the results of the current field applications with respect to contaminant reduction are promising, and no major adverse impacts on the environment have been reported so far. It is thus expected that these trials will contribute to promoting the technology in Europe.

Using dynamic NMR spectroscopy, the kinetic isotope effects of the degenerate single hydron transfer in the conjugate 15 N-labeled porphyrin anion Por-Hdissolved in organic solvents have been measured as a function of temperature. Por-Hwas generated by dissolving the labeled parent compound porphyrin together with the phosphazene base 1,1,1,5,5,5-hexakis(dimethylaminoamino]-1λ 5 ,3λ 5 ,5λ 5 ,1,4-triphosphazadiene (tHept-P 4 ) in organic solvents. In addition, by reaction of porphyrin with the base 1,1,1,5,5,5-tetrakis[tris(dimethylamino)phosphoranylidene]amino]phosphonium fluoride (P 5 + F -) Por-Hcould be embedded into the solid state and its tautomerism followed by 15 N CPMAS NMR. Surprisingly, within the margin of error, the degeneracy of the tautomerism was not lifted in the solid state and the rate constants of the proton transfer were identical in the liquid and the solid. The kinetic isotope effects at 240 K (extrapolated) are given by k H /k D) 34 and k H /k T ≈ 152. The size and the temperature dependence of the isotope effects indicates a proton tunneling mechanism as in the parent porphyrin where this process is nondegenerate. However, the proton tunneling contribution is much larger in the anion as there the process is degenerate. These findings are reproduced in terms of a modified Bell tunnel model for both systems.

No abstract

The medical records of 59 rabbits with uterine disorders were assessed retrospectively. Ten animals were presented because of vaginal discharge; the reasons for presentation of the remaining 49 rabbits included mammary masses, skin tumours, anorexia and poor general health. All the rabbits underwent a clinical examination, and 54 were examined by ultrasonography and/or radiography. Forty-five rabbits underwent ovariohysterectomy and the other 14 rabbits were euthanased, three because of pulmonary metastases and 11 because of very poor health unrelated to their uterine disease. The genital tracts of all the rabbits were submitted for histological examination. Endometrial hyperplasia (in 24 rabbits) and adenocarcinoma (in 18 rabbits) were the most common uterine disorders; in a further 11 cases both conditions were observed. The remaining six rabbits had other uterine disorders. Four rabbits that were presented with adenocarcinoma of the mammary gland were found to have concurrent uterine disorders. The mean age of the rabbits with endometrial hyperplasia was 4.5 years, and that of the rabbits with adenocarcinoma was 6.1 years. Four rabbits had ovarian tumours.