Retention of a six-membered ring in the reaction of 2-dialkylaminobenzo[e]- 1,3,2-dioxaphosphinin-4-ones with Pentafluorobenzaldehyde: O,N-exchange at phosphorus

The title reaction leads to the formation of diastereoisomeric 2-[(dialkylamino)(pentafluorophenyl)methyl]benzo[e]-1,3,2-dioxaphosphinine-2, 4-diones in a ratio of 70: 30. The configuration of chiral centres for the preferable diastereoisomer was determined by single crystal X-ray diffraction analysis. © 2013 Mendeleev Communications. All rights reserved

Dynamics of viscous amphiphilic films supported by elastic solid substrates

The dynamics of amphiphilic films deposited on a solid surface is analyzed for the case when shear oscillations of the solid surface are excited. The two cases of surface- and bulk shear waves are studied with film exposed to gas or to a liquid. By solving the corresponding dispersion equation and the wave equation while maintaining the energy balance we are able to connect the surface density and the shear viscocity of a fluid amphiphilic overlayer with experimentally accessible damping coefficients, phase velocity, dissipation factor and resonant frequency shifts of shear waves.Comment: 19 pages, latex, 3 figures in eps-forma

Endocrinologic, neurologic, and visual morbidity after treatment for craniopharyngioma

Craniopharyngiomas are locally aggressive tumors which typically are focused in the sellar and suprasellar region near a number of critical neural and vascular structures mediating endocrinologic, behavioral, and visual functions. The present study aims to summarize and compare the published literature regarding morbidity resulting from treatment of craniopharyngioma. We performed a comprehensive search of the published English language literature to identify studies publishing outcome data of patients undergoing surgery for craniopharyngioma. Comparisons of the rates of endocrine, vascular, neurological, and visual complications were performed using Pearson’s chi-squared test, and covariates of interest were fitted into a multivariate logistic regression model. In our data set, 540 patients underwent surgical resection of their tumor. 138 patients received biopsy alone followed by some form of radiotherapy. Mean overall follow-up for all patients in these studies was 54 ± 1.8 months. The overall rate of new endocrinopathy for all patients undergoing surgical resection of their mass was 37% (95% CI = 33–41). Patients receiving GTR had over 2.5 times the rate of developing at least one endocrinopathy compared to patients receiving STR alone or STR + XRT (52 vs. 19 vs. 20%, χ2P < 0.00001). On multivariate analysis, GTR conferred a significant increase in the risk of endocrinopathy compared to STR + XRT (OR = 3.45, 95% CI = 2.05–5.81, P < 0.00001), after controlling for study size and the presence of significant hypothalamic involvement. There was a statistical trend towards worse visual outcomes in patients receiving XRT after STR compared to GTR or STR alone (GTR = 3.5% vs. STR 2.1% vs. STR + XRT 6.4%, P = 0.11). Given the difficulty in obtaining class 1 data regarding the treatment of this tumor, this study can serve as an estimate of expected outcomes for these patients, and guide decision making until these data are available

Retention of a six-membered ring in the reaction of 2-dialkylaminobenzo[e]- 1,3,2-dioxaphosphinin-4-ones with Pentafluorobenzaldehyde: O,N-exchange at phosphorus

The title reaction leads to the formation of diastereoisomeric 2-[(dialkylamino)(pentafluorophenyl)methyl]benzo[e]-1,3,2-dioxaphosphinine-2, 4-diones in a ratio of 70: 30. The configuration of chiral centres for the preferable diastereoisomer was determined by single crystal X-ray diffraction analysis. © 2013 Mendeleev Communications. All rights reserved

Retention of a six-membered ring in the reaction of 2-dialkylaminobenzo[e]- 1,3,2-dioxaphosphinin-4-ones with Pentafluorobenzaldehyde: O,N-exchange at phosphorus

The title reaction leads to the formation of diastereoisomeric 2-[(dialkylamino)(pentafluorophenyl)methyl]benzo[e]-1,3,2-dioxaphosphinine-2, 4-diones in a ratio of 70: 30. The configuration of chiral centres for the preferable diastereoisomer was determined by single crystal X-ray diffraction analysis. © 2013 Mendeleev Communications. All rights reserved

Nonlinear Electromagnetic Properties of Thinfilm Nanocomposites (CoFeZr)_x(MgF₂)_100−x

The aim of this work is a comprehensive study of the effect of variable atomic composition and structural-phase state of (CoFeZr)x(MgF2)100−x nanocomposites (NCs) on their nonlinear electronic and magnetic/magneto-optical properties. Micrometer-thick nanocomposite layers on the glass substrates were obtained by ion-beam sputtering of a composite target in the argon atmosphere in a wide range of compositions x = 9–51 at·%. The value of the resistive percolation threshold, xper = 34 at·%, determined from the concentration dependencies of the electrical resistance of NCs, coincides with the beginning of nucleation of metallic nanocrystals CoFeZr in MgF2 dielectric matrix. The absolute value of maximum magnetoresistance of NCs is 2.4% in a magnetic field of 5.5 kG at x = 25 at·%, up to the percolation threshold. Two maxima appear in the concentration dependencies of magneto-optical transversal Kerr effect, one of which, at x = 34 at·%, corresponds to the formation of CoFeZr alloy nanocrystals of a hexagonal structure, and the second one at x = 45 at·% corresponds to the phase transition of nanocrystals from a hexagonal to a cubic body-centered structure. The magnetic percolation threshold in (CoFeZr)x(MgF2)100−x system at xfm = 34 at·%, with the appearance of a hysteresis loop and a coercive force of Hc ≈ 8 Oe, coincides with the resistive percolation threshold xper = 34 at·%. Concentration dependence of the coercive force showed that at low contents of metallic alloy x c = 0). With an increase of the alloy content, in the region of magnetic and resistive percolation thresholds, NCs exhibit a magnetically soft ferromagnetic character and do not change it far beyond the percolation threshold, with the maximum value of the coercive force Hc < 30 Oe