Acriflavine-resistant mutant of Streptococcus cremoris

Selection for resistance to acriflavine in Streptococcus cremoris resulted in cross-resistance to the drugs neomycin, streptomycin, ethidium bromide, mitomycin C, and proflavine. Furthermore, the mutants showed resistance to lytic bacteriophages to which the parental strain was sensitive, and, unlike the parent, the mutants grew well at higher temperatures (40 degrees C). Revertants selected independently either for temperature sensitivity or for acriflavine sensitivity lost resistance to all the drugs and dyes but retained the bacteriophage resistance phenotype. The acriflavine-resistant mutation resulted in an increase in resistance by the bacterial cells to sodium dodecyl sulfate, a potent solvent of lipopolysaccharide and lipoprotein. It is suggested that the acriflavine resistance mutation determines the synthesis of a membrane substance resistant to higher temperatures.     

Influence of a Montmorillonite Clay on the Properties of Griseofulvin Tablets

Direct compression techniques were used to prepare tablets containing griseofulvin-montmorillonite adsorbates. The resulting tablets displayed uniform and consistent properties which compared quite favorably with commercial dosage forms coataining micronized griseofulvin. Dissolution studies were conducted on powdered samples from the various tablets and these studies indicated that the highest levels of griseofulvin in solution after twenty minutes were found with the griseofulvin-montmorillonite samples.     

An X-ray diffraction and DTA study of the ferroelectric transition in barium sodium niobate

The structural behaviour of barium sodium niobate has been studied in the region of the ferroelectric Curie point ( 580°C) by means of high-temperature X-ray diffraction and DTA. No significant changes in the diffraction pattern are observed until temperatures in the vicinity ofT _c are reached; the patterns are then consistent with the structure retaining tetragonal symmetry through the transition but assuming a significantly lowerc/a ratio. The results are compared with thermal expansion measurements made on single crystals. The thermal effect associated with the transition has been used to determine the order of the transition and the results suggest that the reaction is first order.     

Creativity and the need for associative novelty.

Based on J. P. Houston and S. A. Mednick's experiment (see record 1963-06699-001), the differential reinforcing properties of associative novelty were assessed for high-creative and low-creative Ss. 80 undergraduates, the top and bottom 26% of a pool of 156 Ss who had taken the Remote Associates Test (RAT), participated in a 2*4 factorial experiment. The independent variables were creativity, measured by the RAT, and type of reinforcement of nouns; the dependent variable was the number of nouns chosen over blocks of 40 trials. Each S saw 180 cards with 2 words, a noun and a nonnoun, typed on each card. If S chose the nonnoun, E responded with its most common associate. If S chose the noun, E responded with a very common associate, a moderately common associate, a very uncommon associate, or a similar-sounding word, depending on the experimental condition. Neither main effect of creativity nor type of reinforcement was significant (p > .05); only the effect of trials was significant (p     

Tower building on resilient mountings

The Rank Hovis McDougall Centre in London was constructed at the intersection of two trunk roads and over two underground railway routes. One trunk road passes over the substructure. Protection from noise and vibration was necessary, and the building was double glazed as well as being mounted on resilient pads. It is the largest building in the UK to be mounted in this way. The mounting of a tower on these resilient type springs necessitated restraint to lateral translation movement and from movement due to steady and impact gusts of wind. This was achieved by 'hard stops' of adjustable flat jacks and bolts suitably isolated.

Although noise and vibration are apparent in the basement car park, the level of disturbance from outside sources is not detectable within the insulated superstructure in spite of the very low level of background noise within the building.