Trifluoromethanesulphonic acid catalysed transalkylation between tetrabromobisphenol-a and toluene for the production of 2,6-dibromophenol

The preparation of 2,6-dibromophenol is described. This compound, useful as raw material for brominated poly(phenyleneoxide) and pyrogallol or derived pharmaceuticals/pesticides, was prepared in 80% (isolated) yield by a transalkylation reaction between tetrabromobisphenol-A and toluene. The catalyst, trifluoromethanesulphonic acid, can be simply recovered and recycled. Perfluorinated resin sulphonic acid (NAFION-H®, DuPont) did not effectively catalyse this transalkylation.     

Mena, a relative of VASP and Drosophila Enabled, is implicated in the control of microfilament dynamics

This paper examines the effects of exposure to mass media messages promoting family planning on the reproductive behaviour of married women in Nigeria using cross-sectional data. Longitudinal data are also used to ensure that exposure to media messages pre-dates the indicators of reproductive behaviour. Cross-sectional analysis suggests that: (1) contraceptive use and intention are positively associated with exposure to mass media messages, and (2) women who are exposed to media messages are more likely to desire fewer children than those who are not exposed to such messages. Similarly, analysis of the longitudinal data shows that exposure to mass media messages is a significant predictor of contraceptive use. Thus, exposure to mass media messages about family planning may be a powerful tool for influencing reproductive behaviour in Nigeria.     

Vakuumgerechte Werkstoffe und Verbindungstechnik

In Part 1 (Henning, Materials used in Vacuum Technology), the application possibilities of different materials in vacuum technology were described. Part 2 describes the most important non-detachable connections of these materials to produce components that can be used in vacuum technology. The following processes are suitable for this purpose:

• ○ Welding

• ○ Soldering

• ○ Glueing

• ○ Fusion

For this reason, these four processes will be discussed in detail here; their advantages and disadvantages described and their worthiness for use in vacuum technology indicated. It should be noted here that other nondetachable connections such as rivets, point welding, projection seam welding or roll seam welding do not meet the demands of gas tightness made in vacuum technology and cannot, therefore, be used for such purposes.     

New telechelic polymers and sequential copolymers by polyfunctional initiator-transfer agents (inifers)

Summary Novel oxycarbonyl isocyanate telechelic polyisobutylenes have been prepared by conversion of hydroxylterminated polyisobutylenes with N-chlorocarbonyl isocyanate. This reaction is free from side-reactions and provides highly reactive isocyanate-terminated polyisobutylene prepolymers. Conversion of these prepolymers with glycol, urea, pentaerythritol, and polyethylene glycol led to linear chain extension, crosslinking, and multiblock copolymer formation, respectively.     

Iterative analysis of Markov regenerative models

Conventional algorithms for the steady-state analysis of Markov regenerative models suffer from high computational costs which are caused by densely populated matrices. In this paper, a new algorithm is suggested which avoids computing these matrices explicitly. Instead, a two-stage iteration scheme is used. An extended version of uniformization is applied as a subalgorithm to compute the required transient quantities “on-the fly”. The algorithm is formulated in terms of stochastic Petri nets. A detailed example illustrates the proposed concepts.     

Spherical sample holders to improve the susceptibility measurement of superparamagnetic materials

The design of two custom sample holders with a spherical cavity for commercial vibrating sample magnetometer systems is described. For such cavities, the magnetization M[over ->] and the internal magnetic field H(i)[over ->] of a sample are both homogeneous. Consequently, the material parameter M(H(i)) of a sample can be determined even for liquids and powders with a high magnetic susceptibility.     

Die Mikroflora des Sauerteiges

Zusammenfassung Es wurden Ermittlungen über das Vitaminbedürfnis der an der Sauerteiggdrung beteiligten Milchsäurebakterien der UntergattungenThermobacterium, Streptobacterium andBetabacterium angestellt.Von den überprüften Sauerteigbakterien waren 54 Stämme aus sog. Reinzuchtsauerteigen und 49 Stämme aus Sauerteigen isoliert worden. Alle Sauerteigbakterien erwiesen sich biotin-, vitamin B₆-, vitamin B₁₂-, pyridoxamin- und pyridoxalautotroph. Ohne Ausnahme besteht bei den Sauerteigbakterien ein Bedürfnis an Pantothensäure und Nicotinsäure. Die Bedürftigkeit der Sauerteigbakterien an Folsäure, Vitamin B₂ und Vitamin B₁ ist von Art zu Art wechselnd.Das Vitaminbedürfnis der verschiedenen Gruppen von Sauerteigbakterien steht weitgehend in Übereinstimmung mit dem Bedürfnis der jeweils zum Vergleich herangezogenen Milchsäurebakterien definierter Art. Die Befunde geben somit eine Bestätigung der anhand des Zuckerspektrums vorgenommenen Zuordnung der Sauerteigbakterien zu den ArtenLactobacillus aeidophilus, L. casei, L. plantarum, L. fareiminis, L. brevis, L. brevis var. lindneri, L. fermentum undL. fructivorans.

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The microflora of sourdoughV. Communication: The vitamin requirement of lactic acid bacteria (Genus lactobacillus Beijerinck) of sourdough starter and sourdough

Summary Research was carried out on the vitamin requirements of lactic acid bacteria of the subgeneraThermobacterium, Streptobacterium andBetabacterium, which have a part in the sourdough fermentation. Of the investigated sourdough bacteria 54 strains were isolated from the Reinzuchtsauer (a starter culture) and 49 strains from sourdough. All sourdough bacteria were biotin-, vitamin B₆-, vitamin B₁₂-, pyridoxamine-and pyridoxal-autotroph. All sourdough bacteria showed a requirement for pantothenic acid and nicotinic acid. The requirement of sourdough bacteria for folic acid, vitamin B₂ and vitamin B₁ varied from species to species. The vitamin requirements of the different species of sourdough bacteria mostly agree with the requirements of reference strains of lactic acid bacteria (ATCC-strains, DSM-strains) with which they were compared. The results are therefore a confirmation for having assigned the sourdough bacteria from their sugar fermentation reactions to the speciesLactobacillus acidophilus, L. casei, L. plantarum, L. farciminis, L. brevis, L. fermentum, L. fructivorans andL. brevis var. lindneri.

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Nr. 4470 der Veröffentlichungen der Bundesforschungsanstalt für Getreide- und Kartoffelverarbeitung, Detmold

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Diese Untersuchungen wurden ermöglicht durch eine finanzielle Förderung seitens des Bundesministeriums für Forschung und Technologie im Rahmen des Programmes Biologie und Technik