Struktur und Eigenschaften von ABS-Polymeren. IV. Zum Einfluß der thermischen Vorbehandlung auf das Deformationsverhalten von ABS-Pfropfpolymerisaten

The influence of thermal history on the thermomechanical properties of a graft polymer (ABS) is investigated. The thermal pretreatments are: sharp quenching from above the glas-transition of the matrix resin, annealing below the glas transition. A first characterization of the influence of these two pretreatments is done by measuring density, probe length as function of temperature and by DTA. The less modulus in the region below the glas transition of the matrix resin is very sensitive to thermal pretreatment. Small but reproducible influences are observed in the glas transition region of the polybutadien particles. At room temperature stress-strain measurements are achieved until fracture happens. Crazing is observed (which is often called stress-whitening) in all cases, but the extent of craze growing is dependent on thermal history. The measurements are completed by scanning micrographs of the fracture surfaces. Annealing of the fracture surfaces gives additional informations. The results are discussed using the concept of free volume which is variated by thermal pretreatment. At room temperature the phase-boundary between polybutadion particle and matrix resin is considered as transition zone from high to small hole concentration. The sharpness of this zone is supposed to be a decisive parameter for the macroscopic deformation behaviour.     

Der Einfluß von Emulgatoren auf das Verhalten von Fett im Eismix während des Reifens

Effect of Emulsifiers on the Behaviour of Fat in Ice Cream Mix During Ageing Ageing of ice cream mix takes up most of the time in the production of ice cream. This is due to the fat crystallisation which is important for the processing of the mix in the freezer. The influence of emulsifiers is investigated with regard to their degree of saturation and their hydrophilic-lipophilic balance using simple laboratory methods such as the determination of the free extractable fat and the emulsion stability. Saturated emulsifiers do not show any remarkable changes of the extractable fat and the emulsion stability during the ageing time. Saturated emulsifiers cause an increase of the extractable fat and a deterioration of the emulsion stability. These changes are especially obvious during the first three to six hours of ageing. The definite orientation of the protein-emulsifier membrane around the fat globules is only finished after twelve to twenty-four hours of ageing. This might explain the fact that in practice three hours of ageing are considered as absolutely necessary and that a longer ageing time causes a further improve of ice cream quality.     

Thermochemical production of hydrogen by a vanadium/chlorine cycle. Part 2: Experimental investigation of the individual reactions

Chemical engineering aspects and the chemical practicability of a vanadium/chlorine hydrogen-producing cycle were investigated on a laboratory scale. The most significant results are presented and discussed. The total process was balanced and optimized using the experimental results as the basis. The overall thermal efficiency was calculated to be 42.5% (see Part 1).     

Studies on the enzymatic synthesis of cholesterol: Use of a liver acetone powder

We have defined special conditions for the preparation of an acetone powder of rat liver microsomes which is capable of converting squalene to cholesterol in high yield. This preparation is also useful for the demonstration of cofactor requirements for certain reactions in sterol biosynthesis. Buffer washed acetone powders are virtually completely dependent upon the 105,000 ×g supernatant of rat liver (S₁₀₅) for activity, yet S₁₀₅ by itself is inert in sterol synthesis. The ability of S₁₀₅ to stimulate sterol synthesis is heat liable, nondialyzable, trypsin sensitive, and has been partially purified by ammonium sulfate precipitation and chromatography on Sephadex G-200. These results plus other experiments support the following hypothesis: the 105,000 ×g supernatant of rat liver (S₁₀₅) contains a noncatalytic carrier protein (Sterol Carrier Protein or SCP) which originates from the endoplasmic reticulum, binds the substrate, and makes the substrate reactive to the sterol synthesizing enzymes present in the acetone powder of liver microsomes. The participation of SCP may be an important general mechanism in the biological synthesis of cholesterol. One of 12 papers to be published from the Sterol Symposium presented at the AOCS Meeting, New Orleans, April, 1970.     

Parameters for the measurement of long-term effects of an orally administered drug in organic and functional circulatory disorders. Preliminary communication

In many cases of drug-induced allergic hepatitis, peripheral lymphocytes were transformed by the stimulation with a given drug in the presence of autologous serum. However, when rat liver microsome fraction of soluble liver specific antigen fraction was added to the culture instead of autologous serum, the drug-induced lymphocyte transformation was more efficiently seen than autologus serum, while rat liver mitochondria fraction was less effective. On the other hand, in the cases of allergic drug eruption which did not show any liver injury, the addition of liver subcellular fractions were much less effective to induce the lymphocyte transformation than autologous serum. These results may suggest that liver subcellular component is involved in pathogenesis of drug-induced allergic hepatitis.     

Über die Streuung des Fettgehaltes verschiedener Ölpflanzen I: Winterraps und Sonnenblume

Deviation in Fat Content of Different Oil Yielding Plants To get an insight into the factors and their intensity causing deviation in the oil content of some of the oil yielding plants, the deviating components of winter rape, sunflower, linseed, soybean and mustard species were determined with the help of variance analysis, carried out in widely different experiments with cultivated material as well as in value and control tests. The greatly varying extreme values of the fat content resulted from environmental factors, yearly and local effects as well as genetically dependent family and species differences. The standard deviations show quite clearly that the effects of year, location and species are different in different oil yielding plants.