Curtis W. Hill

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In an effort to learn what factors might mitigate the establishment of Escherichia coli variants bearing major chromosomal rearrangements, we have examined the effects on cell growth of two inversions between rRNA operons. One of these inversions, IN(rrnD-rrnE), had been propagated in a commonly used subline of E. coli K-12 for approximately 30 yr before(More)
Certain Escherichia coli strains bind the Fc fragment of immunoglobulin G (IgG) at the bacterial cell surface. Previous work established that this nonimmune Ig binding depends on several large proteins with apparent molecular masses that can exceed 200 kDa. For E. coli strain ECOR-9, four distinct genes (designated eibA, eibC, eibD, and eibE) are(More)
Influences of process conditions on microstructure and dielectric properties of ceramic-polymer composites are systematically studied using CaCu3Ti4O12 (CCTO) as filler and P(VDF-TrFE) 55/45 mol.% copolymer as the matrix by combining solution-cast and hot-pressing processes. It is found that the dielectric constant of the composites can be significantly(More)
The relative preferences of rhesus monkeys for reward probability versus amount were investigated with procedures which contrasted general experience with specific instructions, and evaluated the relationship between probability-amount combinations and preference strength. Four stimulus objects, each signifying a different combination of reward frequency(More)
Three groups of adult female rhesus monkeys, maintained on low-protein diets (.5 gm, 1 gm, and 2 gm protein per kg body weight, were compared with a control group (4 gm protein per kg body weight) on a food-preference task. Food responsiveness was assessed by presenting 8 small pieces of a certain food, equally spaced about the perimeter of a turntable(More)
Facilitation of the learning of a discrimination reversal task for a reward of food was found in rhesus monkeys after subcutaneous administration of a potent pentafluorinated enkephalin analog. (D-Ala2)-F5-Phe4-enkephalin-NH2. General activity, short-term memory, startle, and analgesia, however, were not significantly affected. In a within-subject design,(More)
Scotopic thresholds of rhesus monkeys were determined over a range of luminance levels, from 1138 to 17.8 x 10(-9) cd/cm2, and grating densities, from .132 to 1.58 lines per cm. The effects of a low-protein diet on these thresholds were also investigated, and standard stimulus objects within the discrimination learning situation were employed. Obtained(More)
In a within-subject design, six rhesus monkeys (3 males and 3 females) received a 100 micrograms/kg injection of one of seven neuropeptides or a diluent control solution and were then tested for activity level, learning (discrimination reversal), short-term memory (delayed response), and for responsiveness to noxious stimuli. One daily injection was made(More)
Infant rhesus monkeys whose mothers were fed diets providing 1, 2, or 4 g of protein/kg body weight/day during pregnancy were tested on 13 behavioral tests during their first 60 days of life. (The diets had been shown to affect significantly the weights and blood protein concentrations of both pregnant and nonpregnant females.) The tests samples a wide(More)
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