Determination of Inosine-5-Monophosphate in Fish Tissue with an Enzyme Sensor

An enzyme sensor for IMP consisted of immobilized enzymes and an oxygen electrode. A nucleotidase (E.C. 3.1.3.5.), nucleoside phosphorylase (E.C. 2.4.2.1.) and xanthine oxidase (E.C. 1.2.3.2.) were immobilized on a membrane prepared from cellulose triacetate, 1,8-diamino-4-aminomethyloctane and glutaraldehyde. Optimum conditions for IMP determination were pH 7.8, 30°C, a flow rate of 1 ml min⁻¹ and sample volume of 20 μl. A calibration curve for IMP was linear up to 15 mM. This sensor could be applied to the determination of IMP in meats of sea bass, mackerel, yellowfish and saurel. Good correlative results were observed between the values obtained by the sensor and the conventional method. The sensor was stable for more than 15 days at 5°C and 100 assays.     

HB型步进电动机一体式分割型阻尼减振方式的提案

结合HB型步进电动机的结构特点提出一种一体式分割型阻尼方式。定性分析了这种方式的原理,并在具体样机上实施,进行了实验研究,说明这种方式的有效性。     

The Glass System SiO2-B2O3-Bap-Na2O for High-Numerical-Aperture Optical Fibers

The glass system SiO₂-B₂O₃-BaO-Na₂O was investigated to obtain high-refractive-index glasses for high-numerical-aperture (N.A.) optical fibers. Compositions having a mole ratio [B₂O₃]/[BaO+Na₂O]=2 have unique properties. They are both highly viscous and chemically durable despite the fact that they contain highly alkaline metals and alkaline-earth metals. Glass properties at this mole ratio are favorable for optical fibers. It is proposed that the composition for core glass of high-N. A. optical fibers be based on this mole ratio.     

Determination of Antigenicity by Radioimmunoassay and of Trypsin Inhibitory Activities in Heat or Enzyme Denatured Ovomucoid

The effects of heat treatment and enzymic digestion on the antigenic reactivity of ovomucoid were studied. This reactivity was mainly examined by a solid phase competitive radioimmunoassay. The trypsin inhibitory activity was also measured to elucidate its relationship to the antigenic reactivity. The antigenic reactivity and trypsin inhibitory activity diminished in parallel with increase of heating time. However, enzymic digestion caused a more rapid decrease in antigenic reactivity than in trypsin inhibitory activity. From these results, it is suggested that the structure of the antigenic determinants is destroyed in a similar manner to that of the trypsin inhibitory active site when ovomucoid is heated, while the former structure is destroyed more easily than the latter by enzymic digestion.