LIQUIFYING COD FISH FRAMES UNDER ACIDIC CONDITIONS WITH A FUNGAL ENZYME

An acidic protease (Newlase A from Rhizopus niveus , Amano) was evaluated as to its ability to reduce viscosity of ground cod fish frames without excessive hydrolysis. Newlase A had an optimal pH of 3.5 and an optimal temperature of 60C with Azocoll as substrate. the enzyme was more stable in the ground fish mixture at pH 3.5 than it was in citrate:phosphate buffer of the same pH. the enzyme hydrolyzed the fish proteins more extensively and decreased the viscosity of the ground fish more between 40–50C over an extended time period than at its optimal temperature of 60C. It is likely that the lower optimal temperature under these conditions is related to its greater stability at the lower temperatures. the energy of activation of the deactivation of the enzyme was 44.5 Kcal per mol-degree. Over a period of 75 min at 45C there was a decrease in viscosity of the ground fish with added enzyme of some two orders of magnitude. After a 3-h incubation, total soluble protein increased from 30% to 48%; the amount of each molecular size fraction produced decreased in the following order: 1–3, < 10, < 1, and 3–10 kdaltons.     

Trapped Electrons in Irradiated Quartz and Silica: I, Optical Absorption

Evidence is given for the correlation between an optical absorption band at 2300 a.u. and an electron spin resonance system developed in quartz after ⁶⁰Co γ-irradiation. The results of bleaching γ-irradiated quartz and silica at 78°K. and at room temperature are presented and discussed. Also, further observations upon annealing these color centers are given.     

Trapped Electrons in Irradiated Quartz and Silica: II, Electron Spin Resonance

The correlation of two paramagnetic defects, observed by the electron spin resonance (ESR) technique, with two optical absorption bands produced by r-ray or neutron irradiation is indicated. The peaks of the two absorption bards fall at ∼2100 8.u. and 2300 a.u. The effective g values for the ESR lines, for a crystal orientation with respect to the magnetic field of 100.1] parallel to H₂, are 2.0006 plusmn; 0.0005 for the 2100 a.u. band, and there are two lines observed for the 2300 a.u. band at [g = 2.0007 and g = 2.00091 ± 0.0005. The correlation of the optical bands and ESR lines was established by a series of bleaching and annealing experiments. These experiments also establish the presence of another center which is not observed directly by either the optical or the ESR technique. ESR lines were observed which were attributed to a hyperfine interaction, A = 7.7 oersteds, of the g = 2.0006 (2100 a.u. band) defect with the Si²⁹ isotope (I = 1/2, 4.7% abundance). Models for these defects, consistent with the experimental data, are suggested.     

Ceramic and Dielectric Properties of Lead Metaniobate Electrical Ceramics

The effect of firing temperature and time on the weight loss, fired porosity, and dielectric properties of lead metaniobate was investigated. The amount of lead oxide lost was found to be a linear function of firing time and in addition increased rapidly as the firing temperature was increased. Specimens fired for 30 minutes at temperatures below 1275°C. had weight losses of less than 1% based on the amount of available PbO present, whereas specimens fired for the same length of time at temperatures greater than 1275°C. had weight losses up to 3.5%. Both a minimum and a maximum point were found in the fired porosity curve of lead metaniobate in the temperature range 1200° to 1350°C. When firing for 30 minutes, the minimum point occurred at about 1225°C. with a porosity value of 8% and the maximum point at 1300°C. with a porosity of 18%. The effect of porosity and weight loss on the dielectric properties of lead metaniobate is presented. The effect of replacing up to 0.7 mole fraction of the lead ion in lead metaniobate by cadmium was investigated. Cadmium additions lowered the Curie temperature and diluted the ferroelectric properties of lead metaniobate.