EXPERIENCE OF SURGICAL TREATMENT OF TUMORS OF PANCREAS AND PERIAMPULLARY ZONE

The results of treatment of 63 patients with tumors of pancreaticoduodenal zone are analyzed. 52 patients had. obstructive jaundice, 47 were older than 50 years. Transcutaneous transhepatic drainage of biliary tracts is preferable as a preoperative method of biliary tracts decompression. Radical operation (pancreaticoduodenal resection) was possible in 10 patients. There were no cases of lethality at this operation. 39 patients had. palliative operations with 1 fatal outcome

Theory of concentration depolarization in the presence of orientational correlations

A theory is presented that incorporates the effect of orientational correlations between luminescent molecules on the fluorescence depolarization due to incoherent energy transfer. The luminescent molecules are embedded in a homogeneous two- or three-dimensional medium which is in an axially symmetric phase with the xy plane as a symmetry plane, and consists of axially symmetric molecules. For the general orientational singlet distribution and the general form of orientational correlations consistent with these symmetries, we derive analytical expressions for the anisotropy of fluorescence emission. In a no back transfer model, numerical results are evaluated for a simple choice of correlations that tend to align nearby molecules. In a pure donor system, the anisotropy of fluorescence is found to be strongly dependent on these correlations. By ignoring them, the critical transfer distance, as obtained from depolarization experiments, may be drastically underestimated. In a system where donors are surrounded by a huge majority of traps, the critical transfer distance can be determined from the intensity of trap fluorescence. Its anisotropy also strongly depends on correlations and may thus give an indication of the correlation length scale

Fe(II)-Catalyzed Isomerization of 4‑Vinylisoxazoles into Pyrroles

The first synthesis of pyrroles by Fe­(II)-catalyzed isomerization of 4-vinylisoxazoles is reported. 5-Alkoxy, amino, and <i>N</i>,<i>N</i>-dialkylamino-3-aryl/alkyl-4-(2-R-vinyl)­isoxazoles afford 2-aryl/alkyl-5-aryl/alkyl/methoxycarbonyl-1<i>H</i>-pyrrol-3-carboxylic acid derivatives typically under mild conditions with cheap and available FeCl₂·4H₂O as a catalyst. The isomerization of 5-alkoxy/amino-3-arylisoxazoles, bearing unsaturated carbo and heterocyclic substituents at the position 4, gives the corresponding fused pyrrolecarboxylic acid derivatives in high yields. DFT calculations were used to elucidate a probable mechanism of the isomerization and explain the influence of steric congestion of the vinyl moiety on the isomerization pathway