O3 Type Research Articles

Studies on the genesis of Vibrio cholerae O139: identification of probable progenitor strains.

Four lines of evidence suggest that the recent outbreak strains of Vibrio cholerae O139 could have emerged from serogroup O1 strains typified by isolates M01 and M0477 described in this paper, which are neither truly classical nor truly E1 Tor in their biotype attributes. Firstly, like all O139 isolates, these O1 strains, isolated in Madras during and before the O139 outbreak, were resistant not only to polymyxin B but also to all biotype-specific choleraphages, i.e. classical phage phi 149 and E1 Tor phages e4 and e5. Secondly, the restriction fragment pattern (RFP) polymorphism displayed by these strains for the cholera toxin (ctx) gene, were identical with those produced by O139 isolates but were different from those of O1 type strains, namely V. cholerae 569B (classical) and V. cholerae MAK757 (E1 Tor). Thirdly, all the O139 isolates and the two O1 isolates carried an identical large number of copies of cholera toxin gene in their chromosomes. Finally, the outer-membrane protein profiles of strains M01 and M0477 were identical to those of O139 isolates but were different from those displayed by strains 569B and MAK757.

低年齢児におけるうしょく発症とその影響因子に関する追跡調査研究 とくに数量化理論２類による

The purpose of this study was to analyze the factors inducing caries. These factors were analysed by using data from the surveys of the same children at the ages of 18 months and 3 years.At the age of 18 months, caries-free children were classified as type O2 by the presence of plaque and/or white spot enamel region, and others were classified as type O1. In these two groups we analyzed on the relationship between caries incidence and three different backgrounds. These backgrounds were environmental, health and daily habit factors. We also analyzed the relationship between each daily habit factor and environmental factors. The results were as follows:1. Both O1 and O2 type were analyzed in regard to environmental, health and daily habit factors by using Hayashi's Quantification Scaling Type 2 Method. The criterion variables were divided into 3 groups: a caries-free group, a group with caries of the anterior region only, and a group with caries of the posterior region. These were determined at the age of three.2. Environmental and health factors had the discriminant principal components. The first one was characterized by the presence or absence of molar caries, and the second by the presence or absence of caries.3. In the O1 type, there were two discriminant principal components in the daily habits. The first one was regularity of daily life, which characterized the caries occurence of the anterior teeth only or of the molar caries. The second one was irregularity of daily habits during the period from 18 months to 3 years old, which characterized the presence or absence of dental caries at the age of three. The children with caries of the anterior teeth showed regularity of daily life and good conditions at home. On the other hand, the children with molar caries had no regularity of daily life and a poor environment at home. The caries-free group showed restriction or control of intake of sweets and habitual brushing by their mothers. The two caries-positive groups showed a tendency that was the opposite of the caries-free group.In the O2 type, parental care at the age of 18 months was the first discriminant principal component, which characterized the presence or absence of anterior teeth caries. The caries-free group showed good daily habits at the age of 18 months. The children with anterior teeth caries had poor habits. The second discriminant principal component was control of eating habits during the period from 18 months to 3 years, which characterized the presence or absence of molar caries. Caries-free children showed good eating habits during this period and brushed their own teeth more than twice a day at the age of three. Children with molar caries showed the opposite tendency at the age of three.4. The Type 2 Method of Hayashi's Quantification Scaling was applied to the analyses on the relationship between each category of daily habits and environmental factors. Each category and change was used as the criterion variables. There were some problems regarding eating habits and contents of meal at the age of 18 months. At this time, the monthers' ages were between 21 to 27. There were some problems regarding stopping bottle feeding in the first or second child among the group of mothers who were over 31. There was some tendency toward prolonged bottle use, delayed toilet training, finger sucking, and beverage intake during the night in the families comprising three generations, where the mothers were over 31. Regional difference had the most influence on snack intake.

Complexing of ozone with aromatic compounds

1. Ozone forms 1∶1 complexes with benzene, fluorobenzene, chlorobenzene, bromobenzene, toluene, ethylbenzene, and benzyl chloride. Stability constants have been determined for these complexes at -10°C. 2. A study of the relation between the logarithm of the equilibrium constant and the Hammettσ-m values for the various substituents log K0=−0.54,ρ=−1.74 has shown the inductive effect from the substituent X to be the principal factor in fixing the equilibrium constant in reactions of the ArX+O3⇆ArX·O3 type. 3. The values of the heats of complexing of ozone with mono substituted benzenes (ΔH0) range from −1.4 to −2.6 kcal/mole, while the corresponding entropies of formation (ΔS0) range from −9.9 to −11.8 cal/ (mole·deg), values close to those for aromatic hydrocarbon complexes with acceptors such as iodine, iodine monochloride, and sym-trinitrobenzene.

New Aspects in Ferroelectric Energy Sources for Impact Fuzes

AbstractIn order to find materials with increased specific electrical energy, especially for impact fuzes, the irreversible conversion of mechanical to electrical energy in ferroelectric ceramics of the Pb(Zr1‐xTix) O3 type with a considerable proportion of zirconium is studied. The depolarization of the ceramics is measured for shock compressions between 0 and 30 kbar. The maximum electrical energy, obtained at about 18 kbar, is of the order of 1.8 J/cm3 with Pb(Zr0.965Ti0.035)03 + 1% Nb2O5 and of the order of 0.8 J/cm3 with a Pb(Zr0.54Ti0.46)03 + 1% Nb205. As an example for application, the initiation of a 3.5 ω bridge wire PETN detonator is described.

Behaviour of non-linear ferroelectric ceramics under shock waves

The irreversible conversion of mechanical to electrical energy in ferroelectric ceramics of the Pb(Zr1-xTix)O3 type with a considerable proportion of zirconium is studied. The depolarization of the ceramics is studied for shock compressions between 0 and 30 kbar. The maximum electrical energy obtained at about 18 kbar, is of the order of 1.8 J/cm3 with a Pb(Zr0.965Ti0.035)O3 + 1% Nb2O5 and of the order of 0.8 J/cm3 with a Pb(Zr0.54Ti0.46)O3 + 1% Nb2O5.

Ferroelectric ceramics: Application to mechanical electrical energy conversion under shock compression

Abstract The irreversible conversion of mechanical to electrical energy in ferroelectric ceramics of the Pb(Zr1-x Tix)O3 type with a considerable proportion of zirconium is studied. The depolarization of the ceramics is studied for shock compressions between 5 and 100 kbar. The maximum electrical energy obtained at about 20 kbar, is of the order of 1.8 J/cm3 with a Pb(Zr0.965Ti0.035)O3 + 1% Nb2O5. The energy conversion efficiency decreases when the shock intensity exceeds 25 kbar.

Electric field dependence of the dielectric constant of PZT ferroelectric ceramics

Bias (dc electric field) dependence of the dielectric constant of ferroelectric ceramics of the Pb(Zr,Ti)O3 type has been investigated. Measurements were carried out at various temperatures in the ferroelectric phase and at several frequencies between 1 kHz and 1 MHz. The bias characteristics of the dielectric constant show a temperature-dependent asymmetry in the electric field direction. A model in which the coercive fields of the 180° and 90° domains are distributed around some average value is considered. The total dielectric constant of the material is calculated by considering the contributions of each type of domain, taking into account the difference between the differential and incremental dielectric constants. This model explains the dependence of dielectric constant on electric field. A comparison of the calculated and experimental results is presented.

Growth of Single Crystals of Ba(B′0.33 Ta0.67)O3 Perovskite-type Compounds

A REVIEW of the literature revealed that a considerable effort has been expended in the past few years on investigations of a large number of new compounds with the general formula, A(B′xB″x)O3, where B′ and B″ are two different elements in the octahedrally co-ordinated cation position of the perovskite structure1. Most of the effort, such as the investigations concerned with ordering of the B ions2–7, has been directed specifically toward the preparation and X-ray characterization of these compounds and, therefore, only a relatively small amount of information is available on their electrical properties. As a consequence, attempts were made at the United Aircraft Research Laboratories to obtain single crystals of A(B′xB″y)O3 type compounds so that meaningful electrical measurements could be made. The purpose of this communication is to report the preparation and properties of single crystals of compounds with the general formula, Ba(B″0.33TaPrime;0.67)O3.