MO-LCAO Calculations of Polymethines

Idealized polymethines are defined as conjugated chain molecules with complete bond equilization and charge alternation. A constant π-bond order along the chain with N atoms has been derived for three types of polymethines which differ by the nature of the heteroatomic end groups. Corresponding to the number of π-electrons they are termined (N + 1)π-, Nπ- or (N ? 1)π-polymethines. This classification embraces closed shell as well as open shell systems. The relations for the energy eigenvalues, coefficients and derived quantities have been obtained in closed form. The results for the different classes of polymethines are strongly related. Their molecular properties should be similar.     

Preliminary analyses of natural radionuclides in selected Turkish power plant lignites

This preliminary study presents the experimental results concerning the concentrations of selected radionuclides (²³⁸U, ²³²K, ²²⁶Ra, ²³²Th) in Af?in-Elbistan, Çan, Çay?rhan, Erzurum, Göynük, Kangal, Orhaneli, Saray, Seyitömer, Soma, Tunçbilek, Yata?an and Yeniköy lignites, which are primarily utilized as fuel for thermal power plants in Turkey. Gamma-spectrometry of 39 representative lignite samples gave results with the following concentration ranges: 8 to 296 Bq/kg for ²³⁸U, 3 to 79 Bq/kg for ²³²Th, 17 to 360 Bq/kg for 40K, and 5 to 130 Bq/kg for ²²⁶Ra. The ²³⁸U results reported here are higher than other literature values for various world coals, earth's crust and world average.     

Buchbesprechungen

Ohne Zusammenfassung     

Das Solvosystem Phosphoroxychlorid, 23. Mitt.: Photometrische Titrationen von Chloriden mit Eisen(III)-chlorid

Zusammenfassung Zahlreiche kovalente Chloride bilden mit FeCl₃ in POCl₃ Chloroniumtetrachloroferrate. HgCl₂, BCl₃, TiCl₄, SnCl₄ und PCl₅ geben ein Chloridion, ZnCl₂ und AlCl₃ zwei Chloridionen, letzteres zum Teil auch das dritte Chloridion an FeCl₃ ab. Die Donorstärke nimmt in der Reihe Et₄NClKCl1/2 ZnCl₂ 1/2 AlCl₃>TiCl₄>PCl₅1/3 AlCl₃[SbCl₆]^–HgCl₂ >BCl₃SnCl₄ ab. SbCl₅ ist in POCl₃ ein stärkerer Akzeptor als FeCl₃. Die Unterschiede gegenüber dem Lösungsmittel Phenylphosphoroxychlorid werden diskutiert.Mit 1 Abbildung22. Mitt.:M. Baaz, V. Gutmann undL. Hübner, Mh. Chem.91, 694 (1960).     

Ionization in antiproton-hydrogen collisions

Employing the semiclassical approximation we calculate within the coupled-state formalism the ionization probability in antiproton-hydrogen (p+H) collisions. In particular we investigate the adiabatic ionization at the distance of closest approach in almost central collisions. Striking differences in the electron excitation probability compared with proton-hydrogen (p+H) collisions are predicted.     

Über die Reproduzierbarkeit der turbidimetrischen Bestimmung von Phosphorspuren mit Strychninmolybdostickstoff(V)säure

Microchimica Acta - Mit der turbidimetrischen Strychninnitrat-Methode für Phosphorspurenbestimmung nach der Version von Hegedüs und Dvorszky kann man nur dann ausgezeichnete...     

Gas-chromatographische Trennung isomerer aromatischer C6-C10-Kohlenwasserstoffe

Separation of isomeric aromatic hydrocarbons from each other has been obtained using packed columns and Bentone 34 modified with silicone oil and lanolin. For maximum resolution the proportions of the modifying agents are very important. Retention data and chromatograms of two different column types are given (column 1∶6% Bentone 34; 2,5% lanolin; 1,5% silicone oil. Column 2∶10% silicone oil; 5% bentone 34; 4% lanolin)     

An immobiline DryStrip application method enabling high-capacity two-dimensional gel electrophoresis

In the field of proteomics the need to detect low-abundance cellular components, such as regulatory proteins, is of critical importance. Two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) is one of the most commonly used separation tools for these biological investigations. In this paper we report an alternative micropreparative 2-D PAGE sample application method, called the "paper bridge loading" method. This method makes it possible to apply a larger sample volume to commercially available immobilized pH gradient (IPG) strips. The Vh products required for focusing are only marginally longer than those used in analytical experiments. The method was compared to traditional cup loading and in-gel rehydration. With 18 cm long narrow-range Immobiline DryStrip pH 4.5-5.5, the "paper bridge" method allowed the application of 10 mg human plasma proteins compared to 3 mg with traditional loading methods. The corresponding figures using Escherichia coli sample was found to be 6 mg and less than 2 mg, respectively. The paper bridge method also showed the best results in terms of spot resolution and separation of high molecular weight proteins.