Quality-Assurance Technology in Japan

A survey of the state of SQA in Japan finds that the situation is much like, but slightly different than, that in the US.     

Measurement of PLL phase error caused by power supply noise

The measurement of the accumulated phase error of phase-locked loops (PLLs) in microprocessor systems is discussed. A system which creates controlled power supply noise and measures the PLL response is described. Examples of the use of this technique are shown for a PLL used in a 400 MHz microprocessor     

Knowledge, data, and models

The object-oriented approach to integrating knowledge data, and models is examined. Under the object-oriented paradigm, everything is an object, which is itself an encapsulation of data and methods to manipulate and access the data within the object. Thus knowledge, data, and models can be defined as special kinds of objects. Active knowledge/data language (KDL), a functional object-oriented database system is considered, covering the active-KDL-type system and functions, and query-driven simulation     

Influence of aminophylline and 8-(p-sulfophenyl)theophylline on the anticonvulsive action of diphenylhydantoin, phenobarbital, and valproate against maximal electroshock-induced convulsions in mice

Time variation of drinking is substantial and has an effect on aggregate estimates of consumption. In this article it is shown that because of a considerable seasonal variation in consumption (+/- 20%) a serious bias in annual consumption estimates can be expected in surveys with a limited time frame. The present study analyzes drinking data collected in the general population of the Netherlands from March 1985 through December 1985 (including Christmas and New Year's Eve). Since it was expected that sensitivity to temporal fluctuations might not be equal for different methods of measurement, several indices of consumption were compared. Although the assessed seasonal effect varies indeed across types of measurement, across male and female subsample and across types of alcoholic beverage, the general tendency is for consumption to be highest in the spring season and lowest in the autumn. Sales figures fluctuate accordingly. It is evident that the risk of biased estimates is larger the shorter the time frame of the survey. Seasonal variation was highest in the frequency domain. Furthermore, exclusion from the time frame of collective holidays, during which people drink more often and more per occasion (viz., Christmas), increases the risk of biased estimates. Even estimates of abstention, but also regular heavy drinking among women, appear to vary considerably over the three seasons in this study. The main conclusion is that results of comparisons of survey data on drinking, particularly those over time, are more or less invalid if the respective time frames of the surveys do not correspond.     

Purification, characterization, and mechanism of a flavin mononucleotide-dependent 2-nitropropane dioxygenase from Neurospora crassa

A nitroalkane-oxidizing enzyme was purified to homogeneity from Neurospora crassa. The enzyme is composed of two subunits; the molecular weight of each subunit is approximately 40,000. The enzyme catalyzes the oxidation of nitroalkanes to produce the corresponding carbonyl compounds. It acts on 2-nitropropane better than on nitroethane and 1-nitropropane, and anionic forms of nitroalkanes are much better substrates than are neutral forms. The enzyme does not act on aromatic compounds. When the enzyme reaction was conducted in an 18O2 atmosphere with the anionic form of 2-nitropropane as the substrate, acetone (with a molecular mass of 60 Da) was produced. This indicates that the oxygen atom of acetone was derived from molecular oxygen, not from water; hence, the enzyme is an oxygenase. The reaction stoichiometry was 2CH3CH(NO2)CH3 + O2-->2CH3COCH3 + 2HNO2, which is identical to that of the reaction of 2-nitropropane dioxygenase from Hansenula mrakii. The reaction of the Neurospora enzyme was inhibited by superoxide anion scavengers in the same manner as that of the Hansenula enzyme. Both of these enzymes are flavoenzymes; however, the Neurospora enzyme contains flavin mononucleotide as a prosthetic group, whereas the Hansenula enzyme contains flavin adenine dinucleotide.