Zum mechanismus der thermischen abspaltung von chlorwasserstoff aus polyvinylchlorid. 5. Mitt.: Über die verteilung der polyensequenzlängen in thermisch abgebauten technischen polyvinylchloriden und in anwesenheit stabilisierend wirkender substanzen

The rates of dehydrochlorination of commercial poly (vinyl chlorides) and the distribution of the lengths of the resulting polyene sequences may vary widely depending on the origin of the polymer. – In the presence of diphenyllead dichloride the rate of dehydrochlorination is increased, while the resulting discoloration is less intense compared to that of pure poly (vinyl chloride) because of a shift of the polyene sequence lengths distribution. Genuine stabilizers, on the other hand, effect retardation in dehydrochlorination as well as a shift of the sequence lengths distribution towards shorter polyene sequences. The causes for this behavior of admixed stabilizers using lead and cadmium octoate as examples as well as of internally stabilized PVC are discussed.     

Abspaltungsreaktionen an hochpolymeren

Elimination reactions of macromolecular compounds can be initiated by various forms of energy (such as heat and radiation) or by chemical attack. In the elimination reactions to be dealt with in this context either polymers or low-molecular reaction products with olefine structures are formed. Condensation reactions between neighboring monomer units under formation of cyclic units in the polymer chains will, however, not be considered here. The following classes of polymers are surveyed regarding their most important elimination reactions investigated to date, including the resulting structures of the polymers: Polymeric alcohols and ethers, polymeric esters, halogen-containing polymers. Furthermore, several conversions on polymers (Wittig reactions, dehydrochlorination, dehydration) are dealt with, some of which, however, are not completely clarified as yet.     

The crossflow piston bed

The moving piston bed is a device for producing washed crystals from a slurry feed. Necessary for predicting the quality of a conceptual bed geometry is an evaluation method which accurately reveals the flow patterns in the dynamic system. The electrical analog method serves as a versatile guide to an evolutionary development of improved designs.All beds with a submerged drainage port have, for a given geometry, a unique relationship between loss of displacement fluid and rate of bed advance. The hydraulic diagram is unchanged, by the magnitude of applied forces. For rating productive capacity the use of gravity forces as a reference standard is recommended.A crossflow design is developed that predicts a productive rate over three times that achievable by downflow washing.     

Differential effects of 1-naphthaleneacetic acid, indole-3-acetic acid and 2,4-dichlorophenoxyacetic acid on the gravitropic response of roots in an auxin-resistant mutant of arabidopsis, aux1

BACKGROUND/AIMS: Gallbladder mucus itself has been recognized to play an important role in gallstone development. Despite the diverse mechanisms of stone induction and the differences in stone composition, there is a quantitative increase in the epithelial mucus production period before stone formation. As brown pigment stones are found frequently in gallstone disease, we conducted a study on gallbladders with brown pigment stones or combination stones with a brown periphery to evaluate the mucin content in the gallbladder epithelium in comparison to gallbladders with cholesterol stones and those without stones. METHODS: Gallbladder specimens were fixed in 10% formalin immediately after cholecystectomy and then embedded in paraffin. The specimens were sectioned for periodic acid-Schiff-alcian blue (PAS-AB, pH 2.5) double stain to evaluate the intra-epithelial mucin content. The PAS-AB index was calculated as a proportion of the PAS-AB-positive mucin area to the total epithelial area, using a computerized image analyzer. RESULTS: Evaluation of the PAS-AB index on the lining epithelia of gallbladders showed that it was 32.43 +/- 9.96% in gallbladders with brown stones, which is significantly (p < 0.001) higher than in gallbladders with cholesterol stones (15.63 +/- 6. 75%) and gallbladders without stones (9.55 +/- 4.77%). CONCLUSION: The results show that gallbladders with brown stones contain more abundant mucin than gallbladders with cholesterol stones or those without stones. They also suggest that the gallbladder epithelium per se might play a more important role in stone formation in those with brown stones than in those with cholesterol stones.     

Fatigue strength of welded joints in austenitic Cr-Ni steels

Abstract

High quality corrosion resistant Cr-Ni steels are used in many branches of industry. Constructors are faced with the problem of correctly dimensioning statically and dynamically loaded parts, but have little data available for dynamically loaded welded constructions of high alloy austenitic steels. To close this gap fatigue strength tests were carried out on three different steels and five different welded joints.     

Use of an immunoassay as a means to detect polychlorinated biphenyls in animal fat

In this paper we describe the validation and utilization of the Hybrizyme TM DELFIA immunoassay for detecting polychlorinated biphenyls (PCBs) in animal fat. The immunoassay incorporates a rapid sample processing protocol that has been optimized to detect concentrations of PCBs in animal fat at or above 200ng/g. The limit of detection of the assay was less than 50ng/g. When the action level for the DELFIA assay was set at 100ng/g to detect samples having 200ng/g or more PCBs, the false negative rate was estimated at 0.2% . The false positive rate depends on the concentration of PCBs in the sample population and was estimated at 4% and 7% for samples having 10ng/ g and 20ng/g PCBs, respectively. By utilizing the DELFIA assay system to select for positive samples and GC/MS analysis for confirmation analysis, an accurate and cost-effective programme has been established for the high throughput detection of PCBs in animal products.