Spatial pseudoanalytic functions arising from the factorization of linear second order elliptic operators

Biquaternionic Vekua‐type equations arising from the factorization of linear second order elliptic operators are studied. Some concepts from classical pseudoanalytic function theory are generalized onto the considered spatial case. The derivative and antiderivative of a spatial pseudoanalytic function are introduced and their applications to the second order elliptic equations are considered. Copyright © 2011 John Wiley & Sons, Ltd.     

High-pressure clathrate hydrate of acetone

X-ray diffraction study of quenched sample of acetone clathrate hydrate synthesized at 0.8 GPa was carried out. It was shown that the host frameworks of the hydrate comprise uniform cavities which are similar to that of recently characterized structure of high-pressure tetrahydrofurane hydrate. The unique peculiarity of investigated hydrate is decrease in the crystallographic symmetry of the hydrate arising from ordering in guest subsystem.     

The Bergman kernel for the Vekua equation

The paper extends some well-known results for analytic functions onto solutions of the Vekua equation $\partial \overline{{}_z}W=aW+b\overline{W}$ regarding the existence and construction of the Bergman kernel and of the corresponding Bergman projection operator.     

Characterization of deposits produced by TEA CO2 pulsed laser ablation of silicon mono- and dioxide

Silicon based deposits were prepared by TEA CO₂ pulsed laser ablation (PLA) of SiO and SiO₂ targets in the atmosphere of selected gases (N₂, He, Ne, Ar, Kr). These deposits possess high specific area of several hundreds m² per gram. Owing to the high specific area, some chemical groups and hydrogen related radical were detected by means of FTIR and EPR analyses and theoretical calculations: silyl (E′ center) Si, silylen Si:, silanon SiO, POL (peroxy linkage) SiOOSi and/or NBOHC (non-bridging oxygen hole center) SiO, POR (peroxy radical) SiOO and dioxysilirane Si(O)₂. In SiO₂ deposits the concentration of silyl Si resp. POR SiOO was determined to be 5.8 × 10¹⁸/g resp. 6.2 × 10¹⁹/g. In SiO deposits the ratio [Si:]:[Si] = (3.1-5.7) × 10¹⁹/g: (5.3-9.8) × 10¹⁹/g was measured. Estimated concentration of [Si] in deposits was increased nearly five times in comparison with SiO target. After exposure of the SiO deposits to H₂ EPR doublet with hyperfine splitting of 7.7 mT was observed. The best agreement between calculated theoretical and experimental values was found for the model [(HO)₃SiO]₂HSi. FTIR measurements and calculations of the silanol theoretical model clusters enabled us to discuss the chemical surroundings of the silanol and to determine the defects in the deposits.     

Photoswitchable Phosphonate–Fullerene Hybrids with Cholinesterase Activity

Modern progress in photopharmocology calls for new generation of compounds joining bioactivity, photoswitchable properties and high selectivity of response to light wavelength. Introduced here, phosphonate–fullerene hybrids are the first representatives of such compounds. Phosphonate–fullerene hybrids were synthesized on a base of fullerene C₆₀ and organophosphates with the function of photoswitchable cholinesterase activity—phosphorylated thiazolotriazole and aminomalonate compounds and studied with FTIR, UV–VIS spectroscopy and IPC-micro neurotoxin amperometric analysis. As a result of spectroscopic and bioactivity characterization, it was not only demonstrated butyrylcholinesterase (BuChE) inhibition increase in phosphonate–fullerene hybrids compared with pure phosphonates but also pronounced response of inhibition degree to laser irradiation of hybrids. It was found opposite behavior of hybrids as a result of laser irradiation—BuChE inhibition drop-off for thiazolotriazole–fullerene and pronounced growth for aminomalonate–fullerene. The other remarkable peculiarity of presented phosphonate–fullerene hybrids is high selectivity of inhibition change degree to laser wavelength (266 or 325 nm).     

New exact solutions of the massive Dirac equation with electric or scalar potential

A new class of exact solutions for the massive Dirac equation with electric or scalar potential depending on one independent variable is constructed. This construction is based on quaternionic reformulation of the Dirac equation. Copyright © 2000 John Wiley & Sons, Ltd.     

Reactions of dithioxo-1,3,2λ5,4λ5-dithiadiphosphetanes with triorganolead derivatives

The reactions of Lawesson's reagent 1a and its 4-ethoxy homologue 1b with triethyl- and triphenyl(alkoxy)plumbanes 2a,b and -(alkylthio)plumbanes 4a,b were studied. On the basis of these reactions, novel, advantageous methods of synthesizing S-triethyl and triphenylplumbyl derivatives of aryldithio- and trithiophosphonic acids 3a–d and 5a,b were developed. © 1997 John Wiley & Sons, Inc.