Should desmoid fibromas be operated?

The 30-year experience of P.A. Herzen Moscou Cancer Research Institute in the treatment of soft tissue desmoid fibromas (DF) is summarized. A comparative study of effectiveness of surgical, combined, radiation and medicamentous methods was carried out. Frequency of recurrences after surgical treatment made up 94%, after combined treatment with preoperative radiation it decreased 3-fold (27.5%), in cases of postoperative radiation it made up 53%, and after radiation therapy--15.7%. However radiation therapy may have limitations due to necessity for irradiation of large tumour masses and usage of high-dose ionized irradiation which results in development of postradiation tissue damages. Further research brought about an original chemohormonal therapy (tamoxiphen, vinblastin, methotrexate), which provides stable recovery in 81.3% of patients. Principal positions for management of DF are formulated.     

Kinetic melting and crystallization stages of strongly superheated and supercooled metals

The heterogeneous melting/crystallization of metals with different crystallographic lattices in conditions where the phase front propagates on overheated/supercooled media was modeled in the context of the molecular dynamics approach. In order to obtain the temperature dependence of the kinetic velocity in analytical form, the results of atomistic modeling were approximated by the function obtained from the kinetic representations. For the first time, stationary temperature dependences of kinetic velocity ν(T _s ?) for the limit values of superheated/supercooled copper and iron were built.     

Supported palladium nanomaterials as catalysts for petroleum chemistry: 1. Specifics of palladium diacetate reduction with hydrogen on silica gel in catalyst synthesis

The reduction reaction of Pd(II) diacetate, a precursor in nanocatalyst synthesis, with molecular hydrogen on silica gel has been studied. A kinetic model involving the autocatalytic mechanism of Pd(II) reduction to Pd(0) and adequately describing the experimental data has been proposed. Similarities and dissimilarities in the mechanism of this process on silica gel and carbon have been revealed. On the basis of quantum-chemical simulation data, it has been suggested that the differences are due to both a high bond energy of the precursor with the support and modifications in geometry of various Pd(II) diacetate species adsorbed on the surface. The controllable reduction of the precursor makes it possible to manufacture materials with a metal particle size of 1.7–2.8 nm according to transmission electron microscopy data. The materials catalyze the reaction of phenylacetylene hydrogenation to styrene with a high activity and selectivity at 25°C and 1 atm of hydrogen.