Richard James Boylan

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Bacillus subtilis 168ts-200B is a temperature-sensitive mutant of B. subtilis 168 which grows as rods at 30 C but as irregular spheres at 45 C. Growth at the nonpermissive temperature resulted in a deficiency of teichoic acid in the cell wall. A decrease in teichoic acid synthesis coupled with the rapid turnover of this polymer led to a progressive loss(More)
AIM The aim of this study was to compare traditional and newly developed root-end filling materials for resistance to bacterial microleakage. METHODOLOGY Sixty extracted single-rooted teeth were randomly divided into five groups for root-end filling with mineral trioxide aggregate, Super-EBA, TPH composite resin with ProBond dentine bonding agent,(More)
The general biological properties of a temperature-sensitive morphological mutant of Bacillus subtilis (168ts-200B) are described. At the restrictive temperature (45 C), cells grow as spheres which divide irregularly to form grapelike clusters. At the permissive temperature (30 C), the mutant grows as typical B. subtilis rods in short chains. A log-phase(More)
Mutant 168ts-200B, resulting from nitrosoguanidine treatment of Bacillus subtilis 168 (trp(-) C2), exhibits a rod-to-sphere morphogenetic interconversion when the incubation temperature is 30 or 45 C, respectively. Ultrathin sections of rods grown at 30 C, after glutaraldehyde-osmium uranium-lead fixation and staining, show trilaminar cell walls with a(More)
Although it has been established that aspiration of pharyngeal bacteria is the major route of infection in the development of nosocomial pneumonia, colonization of the pharyngeal mucosa by respiratory pathogens has been shown to be a transient phenomenon. It has been suggested that the dental plaque may constitute an additional, possibly more stable,(More)
The problem concerned the resistance to extinction of an alley running response as a function of various combinations of reward sizes (l or 10 pellets) and schedules of reinforcement (50 or 100%). Three experimental phases were used (acquisition, shift of reward, and extinction). Three measures were taken in the alley (start, alley, and goal speed). Animals(More)
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