Catalytic activity of N-heterocyclic carbenes in ring opening polymerization of cyclic siloxanes

Taking advantage of the strong nucleophilic properties of N-heterocyclic carbene (NHC), the efficient catalytic ring opening polymerization (ROP) of cyclotetrasiloxane D₄ was achieved under mild conditions.     

Retention Data for Some Statin-Type Antihyperlipidemic Drugs in Normal-Phase TLC

JPC – Journal of Planar Chromatography – Modern TLC - The normal-phase thin-layer chromatographic behavior of five statin-like drugs — atorvastatin, cerivastatin, fluvastatin,...     

Event recognition by detrended fluctuation analysis: An application to Teide–Pico Viejo volcanic complex, Tenerife, Spain

In this work we investigate the application of the detrended fluctuation analysis (DFA) to seismic data recorded in the island of Tenerife (Canary Islands, Spain) during the month of July 2004, in a phase of possible unrest of the Teide–Pico Viejo volcanic complex. Tectonic events recorded in the area are recognized and located by the Spanish national agency Instituto Geográfico Nacional (IGN) and their catalogue is the only currently available dataset, whose completeness unfortunately suffers from the strong presence of anthropogenic noise. In this paper we propose the use of DFA to help to automatically identify events. The evaluation of this case study proves DFA to be a promising tool to be used for rapidly screening large seismic datasets and highlighting time windows with the potential presence of discrete events.     

Untersuchung des Harns

Analytical and Bioanalytical Chemistry -     

AgI-Ag2O-V2O5 glasses as ion-to-electron transducers for the construction of all-solid-state microelectrodes

A method for the fabrication of ion-selective all-solid-state microelectrodes is presented. The ion-to-electron transduction process takes place into the transducer material. In this approach, AgI-Ag₂O-V₂O₅ glasses, which exhibit ionic and electrical conductivity are applied as ion-to-electron transducers of polymeric membrane microelectrodes. All-solid-state electrodes based on potassium-sensitive poly(vinyl chloride) membranes, deposited directly on the surface of glass composites, exhibited theoretical responses. Their selectivity and durability were comparable to planar microelectrodes containing an internal electrolyte immobilized in the intermediate hydrogel layer. The only disadvantage of the proposed structures was their limited reproducibility. Moreover, it was found that the unmodified AgI-Ag₂O-V₂O₅ glasses can be applied as ion-sensitive membrane of solid-state microelectrodes for the determination of Ag⁺ and I⁻ ions.     

Strong Analyticity of Partly Filled-in Composite Julia Sets

It is shown that a composite Julia set generated by an infinite array of polynomial mappings is strongly analytic when regarded as a multifunction of the generating maps. An example of such a multifunction, the values of which have Hölder Continuity Property, is constructed.The research of the second author was supported by KBN Grant No. 2 P03A 047 22. The authors dedicate this paper to Professor Wieslaw Pleśniak on his 60th birthday     

Isolation of Milligram Quantities of Sanguinarine and Chelerithrine from the Roots of Chelidonium majus L. by Zonal Micropreparative TLC

JPC – Journal of Planar Chromatography – Modern TLC - By use of pH 6.0 acetate buffer a mixture of Chelidonium majus L. alkaloids has been separated, on a classical silica column, into...     

Separation of Statin-Type Antihyperlipidemic Drugs by Reversed-Phase TLC

JPC – Journal of Planar Chromatography – Modern TLC -