Bestimmung von isomeren 4-Nonylphenolen in B?den

Summary It was reported that 4-nonylphenol isomers had been found in high concentrations in sewage sludge. When this sludge is applied to fields there is a risk that soils may be contaminated with nonylphenols. Therefore, a method is described here for the determination of 4-nonylphenol isomers in soil. The steam distillation/solvent extraction technique is used. An essential part of the method is the clean-up step by column chromatography. The determination is performed on a fused silica capillary by a flame ionization or a mass selective detector. Average recoveries from soil samples spiked with 0.1 to 1 mg/kg ranged from 90 to 116%. The detection limit is 0.1–0.05 mg/kg soil (this limit corresponds to the technical mixture of the isomers).     

On initial value problems for quaternionic valued functions

In [2], [6], [7], methods are discussed for solving initial value problems

Zur Synthese ditertiärer Phosphine mit aromatischen Brückengliedern

Zusammenfassung Die Darstellung ditertiärer Phosphine mit aromatischen Zwischengliedern erfolgt bei Umsetzung von Diaryl-oder Dialkylalkalimetallphosphiden mit aromatischen Dihalogeniden in verschiedenen Äthern mit besseren Ausbeuten als durch den bisher beschriebenen umgekehrten Weg der Umsetzung von Aryldilithiumverbindungen mit Halogenphosphinen. Die Untersuchung der Umsetzung von Diphenylphosphinkalium mit - und -Jodnaphthalin zum entsprechenden tertiären Phosphin macht einen direkten nucleophilen Reaktionsmechansmus sehr wahrscheinlich, da durch Fehlen einer Isomerisierung ein Arinmechanismus ausgeschlossen werden muß.     

Switching the Stiffness of Polyelectrolyte Assembly by Light to Control Behavior of Supported Cells

Polyelectrolyte block copolymer micelles assembled thin film is switched in response to local photocatalytic reactions on titanium dioxide, resulting in a layer of variable height, stiffness in response to visible light irradiation. Preosteoblasts migrate toward stiffer side of the substrates.

     

IR reflection spectra of monolayer films sandwiched between two high refractive index materials

Monolayer films adsorbed on substrates with high refractive indices such as metals or semiconductors yield strongly enhanced infrared reflection spectra when they are contacted with a transparent, high refractive index ambient medium and are probed with p-polarized light at high incidence angles. The sensitivity increase arises from the enhancement of the perpendicular electric field within a thin, low refractive index layer sandwiched between two high refractive index materials and gives rise to signal intensity gains up to 2 orders of magnitude in combination with an essentially exclusive detection of only perpendicular surface vibrations. Experimental spectra of ordered monolayer films of octadecanethiol on gold and of octadecylsiloxane on silicon in this sandwich configuration yield enhancement factors between 15 (on Si) and 30 (on gold) compared to conventional grazing incidence external reflection spectra and are governed by a common, simple surface selection rule, which allows immediate quantitative evaluation and comparison of the film structures on different substrates.