Showing papers by "Ministry of Supply published in 1957"

Virulence of Pasteurella pestis.

Abstract: IT has widely been assumed that the antigen thought to constitute the capsule or ‘envelope’ which surrounds plague organisms in vivo 1 and which forms under suitable conditions in vitro 2 is essential for full virulence of P. pestis in mice. This antigen has been isolated by Baker et al. 3 and given the name Fraction 1 (F1). From their studies on the relative abilities of strains to produce F1 and toxin, Englesberg et al. 4 correlated high virulence for mice with ability to produce maximal amounts of F1 and toxin.

Oximes and atropine in sarin poisoning

Abstract: Three oximes, monoisonitrosoacetone (MINA), pyridine-2-aldoxime methiodide (PAM) and diacetylmonoxime (DAM), have been examined in combination with atropine as antidotes in sarin poisoning. When treatment was administered 15 min. before sarin, atropine enhanced the protective effect of MINA and DAM 2 to 3 times and of PAM 9 to 10 times in mice and rats. In mice, rats, and guinea-pigs, atropine increased by no more than 2 times the protective effect of all three oximes when given 30 sec. after sarin. Atropine given to monkeys 1 min. after sarin raised the LD50 approximately 3 times. When given in conjunction with MINA or DAM, the LD50 of sarin was raised 7 to 14 times.

The detection and measurement of water droplets

Abstract: The use of a dyestuff (Naphthol Green B) in gelatine, coated on the slides of a cascade impactor, provides a method for determining the drop-size distribution of fogs and water sprays which is easy to apply in practice and gives a permanent record for subsequent microscopic analysis. Calibration of the stain remaining after evaporation of a droplet impacting on the slide shows it to be, on the average, 2.5 times the diameter of the droplet. The method can be readily used for droplets of less than 1 μ diameter.

3—the subjective assessment of the roughness of fabrics

Abstract: To determine consistency and unanimity in ranking the roughness of fabrics, four groups of six subjects each ware asked to rank sets of fabrics, using as a criterion the discomfort they imagined the fabrics would cause when worn next to the skin. The method of paired comparisons was used: coefficients of consistence for individuals and coefficients of agreement for groups were calculated. A statistically significant agreement among subjects was found for the order of ranking of roughness of the fabrics presented. Individuals differed in their consistency of judgement, although all subjects at all times gave results which were significant.

Pasteurella septica: the Occurrence of Type-Specific Polysaccharides containing Aldoheptose Sugars

Abstract: PIROSKY1 has shown that strains of Pasteurella septica produce lipopolysaccharide antigens with similar properties to the endotoxins of certain other Gram-negative bacteria. We have isolated lipopolysaccharides from some strains of P. septica and studied their serological specificity in relation to the immunological status of the strains as measured by passive protection tests2,3.

Natural occurrence of a new aldoheptose sugar.

Abstract: AT the present time aldoheptose sugars are known to occur naturally only in bacterial polysaccharides. The first of these 7-carbon sugars was recorded by Jesiatis and Goebel1 in a Shigella sonnei product, and during the past few years it has become increasingly clear that aldose sugars of this series are common constituents of bacterial polysaccharides2. Only in three instances have aldoheptoses been isolated and identified; the aldoheptose components of both Shigella flexneri and Escherichia coli products were shown by Slein and Schnell3 and Weidel4 to be L-glycero-D-mannoheptose and in a Chromobacterium violaceum (BN) polysaccharide MacLennan and Davies5 identified D-glycero-D-galactoheptose. In many other polysaccharides the aldoheptose constituent could not be distinguished chromatographically from L-glycero-D-mannoheptose (or its optical enantiomorph D-glycero-L-mannoheptose)6.

A precision dual bridge for the standardization of admittance at very high frequencies

Abstract: The need is stated for a more accurate means of admittance or impedance measurement in order that a general improvement can be made in the accuracy of measurement of other electrical quantities at radio frequencies. A description is given of a precision twin-T dual bridge having a range of admittance measurement associated with coaxial systems between 3 Mc/s and 300 Mc/s. The inaccuracy of measurement does not exceed 0.2% on either component of a complex admittance at a frequency of 200 Mc/s. The calibration of the bridge is based on a range of coaxial susceptance standards whose parameters are calculated from length and time measurements. The dual feature of the bridge enables the true r.f. conductance of its internal standard resistor to be established in terms of these standards; the uncertainty of this determination is not greater than 0.1% for frequencies up to 250 Mc/s. The importance to be attached to the design of coaxial terminations for measuring instruments and standards at these frequencies is emphasized. A practical design is detailed for a coaxial terminal for precision admittance and impedance measuring instruments, and mention is made of a proposed universal coaxial connector system for precision radio-frequency measuring instruments of all types.

A Radio Method of determining the Velocity of a Shock Wave

Abstract: THE study of the physics of shock waves of sufficiently high intensity to produce appreciable gaseous excitation and ionization has in recent years become of increasing interest in relation to the gas dynamics of astrophysical phenomena and to the properties of gases at very high temperatures.

Bacterial protoplasts from Bacillus species by the action of autolytic enzymes.

Abstract: WHEN certain bacteria are suspended in sucrose solution of suitable concentration and incubated with lysozyme, the rigid cell-walls are dissolved away, leaving relatively stable spherical protoplasts1 Lytic enzymes which dissolve the isolated cell-walls of vegetative Bacillus cereus have been found in extracts of mechanically disintegrated resting spores2 and partial autolysates of sporulating cells3 of this organism When heat-treated, intact vegetative cells were treated with preparations of these enzymes, the walls were dissolved, leaving the coagulated cell-contents apparently unchanged It has now been found that when viable organisms are suspended in sucrose solution and treated with these enzymes, relatively stable protoplasts are obtained in good yield

Intensity of the Radio Line of Galactic Deuterium

Abstract: THE possibility of detecting deuterium in the galaxy by observation of a radio spectral line at a frequency of 327 Mc./s. has been discussed by Shklovsky1. He suggested that the line might be observable in absorption towards the galactic centre, a direction in which the background intensity of continuous radio emission is a maximum, and dispersion of the line by Doppler effect from galactic rotation is a minimum.

Brown Stain formed on Wet Cellulose

Abstract: THE phenomenon of the ‘brown stain’ formation on wet cellulosic materials was reported1 in 1934 and has since been studied by Turner2 and his colleagues at Manchester, and by Appel3 and others in the United States, but does not even yet seem widely known. As the effect may be encountered in paper chromatography and with the Weisz4 ‘ring-oven’, it may save trouble to workers in those techniques if attention is directed to it. The effect can readily be seen by putting a strip of filter paper as a wick in distilled water. In a few hours a brown stain is found at the top of the wick, or of its wet portion. The immediate neighbourhood of the stain has a brilliant white fluorescence under ultra-violet light and is strongly dyed by methylene blue (0.1 per cent in water).

Steric Influences on the Structure of Chelating Agents and on the Stability of Metal Chelates

Abstract: 2-PHENACYLPYRIDINE and its derivatives are of interest because of their possible bacteriostatic activity1 and their power to chelate metals. In addition, it has been shown2 that in the solid state they exist, with accountable exceptions, in the resonance-stabilized conjugate chelated enol form (I) rather than in the keto form (II). The purpose of this communication is to record some results of a study of their infra-red spectra, and to point out that they provide interesting examples of the influence of steric hindrance on molecular structure and on the stability of metal chelates.

An Effect of Hexylresorcinol on Bacterial Aerosols

Abstract: DURING the course of some investigations into the effects of volatile germicides on the viability of bacterial aerosols, we have encountered a phenomenon which appears to have escaped the notice of other workers in this field, and which not only accounts for contradictions in some existing experimental results, but also suggests that in certain circumstances substances such as hexylresorcinol may be of considerably greater value as barriers to cross-infections than has been supposed hitherto.

The sheep lungworm Protostrongylus brevispiculum in Great Britain.

Abstract: DURING the past year observations have been made to assess the seasonal pattern of lungworm infection in a flock of sheep grazing on the Wiltshire Downs In the course of the examination of faecal samples from some of these animals first stage lungworm larvae of an unusual type were encountered A description of such larvae could not be found in the literature A search for the adults was, therefore, made This proved to be more complex than had been anticipated as a number of lungworm species new to us were found One of these has been identified as Protostrongylus brevispiculum, and the present record is thought to be the first of the occurrence of this lungworm in sheep in Great Britain