Organic chemistry of superoxide. I. Oxidations of aromatic compounds.

Potassium superoxide is a selective oxidant for aromatic compounds with the order of susceptibility of substituent groups being -SH>-NH₂-OH. Only o- and p- disubstituted amines and phenols are oxidized but monosubstituted thiols react.     

STUDIES OF ADHESION OF METAL PARTICLES TO SILICA PARTICLES BASED ON ZETA POTENTIAL MEASUREMENTS

The zeta-potentials of silica, copper, platinum and gold particles have been measured as a function of pH. The isoelectric points were found to be at pH 3.0, 5.8, 3.0 and 3.5, respectively. In the pH range 3.0 to 5.8 copper and silica particles are oppositely charged and accordingly the coating of silica with copper particles could be demonstrated. In the case of gold and platinum the sign of the charge is such that direct adhesion to silica particles cannot be expected and this was also demonstrated in the case of platinum.     

Bulk ablation of soft tissue with intense ultrasound: modeling and experiments

Methods for the bulk ablation of soft tissue using intense ultrasound, with potential applications in the thermal treatment of focal tumors, are presented. An approximate analytic model for bulk ablation predicts the progress of ablation based on tissue properties, spatially averaged ultrasonic heat deposition, and perfusion. The approximate model allows the prediction of threshold acoustic powers required for ablation in vivo as well as the comparison of cases with different starting temperatures and perfusion characteristics, such as typical in vivo and ex vivo experiments. In a full three-dimensional numerical model, heat deposition from array transducers is computed using the Fresnel approximation and heat transfer in tissue is computed by finite differences, accounting for heating changes caused by boiling and thermal dose-dependent absorption. Similar ablation trends due to perfusion effects are predicted by both the simple analytic model and the full numerical model. Comparisons with experimental results show the efficacy of both models in predicting tissue ablation effects. Phenomena illustrated by the simulations and experiments include power thresholds for in vivo ablation, differences between in vivo and ex vivo lesioning for comparable source conditions, the effect of tissue boiling and absorption changes on ablation depth, and the performance of a continuous rotational scanning method suitable for interstitial bulk ablation of soft tissue.     

Characterization of the spectrum of regular boundary value problems for the Sturm-Liouville operator

On the interval (0, τ), we consider the spectral problem generated by the Sturm-Liouville equation with an arbitrary complex-valued potential q(x) ∈ L ₂(0, τ) and with regular (but not strengthened-regular) boundary conditions. Under certain additional assumptions, we establish necessary and sufficient conditions for a set of complex numbers to be the spectrum of such an operator.     

Formation of extended periodic microstructures by “Point” irradiation of gold film by femtosecond laser pulses

Extended periodic microstructures are formed on a thin gold film by femtosecond laser radiation. The structure length is an order of magnitude larger than the typical size of the irradiated region. The detection of gold photoions generated in the process of the microstructuring ensures a high-sensitivity on-line diagnostics of this phenomenon.     

Ueber die Bestimmung des Phenols in Seifen und Desinfectionsmitteln

Ohne Zusammenfassung