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K R Lawson

Publications and source records attributed to K R Lawson.

4 recordsLinked to original sources
PubMed1991

2-Chloro-1-(2,4-dichlorophenyl)-3-(1H-imidazol-1-yl)-2-phenylpropan-1-one hydrochloride, a novel, nonmutagenic antibacterial with specific activity against anaerobic bacteria.

1-(2,4-Dichlorophenyl)-2-phenylpropen-1-one (2) is identified as a potent antibacterial agent. A compound, 2-chloro-1-(2,4-dichlorophenyl)-3-(1H-imidazol-1-yl)-2-phenylpropan++ +-1-one (5) has been designed with the intention of its acting as a pro-drug, liberating the lethal species 2 specifically within the target anaerobic bacterial cell following bioreduction by bacterial ferredoxin or related electron transfer proteins. The synthesis and biological activity of 5 is described and compared with the activities of the analogous alpha-bromo ketone 6 and alpha-fluoro ketone 7. Synthesis of 6, 7, and the corresponding alpha-hydroxy ketone 11 is also described.

Alkenes↗
PubMed1990

Long-term stability of individual differences in sustained attention in the early years.

The goal of this longitudinal study was to explore whether early measures of attention and inattention would be predictive of later attentiveness and whether there was any evidence of stable individual differences in attentiveness. Both full-term and preterm children were observed at 1, 2, and 3.5 years in free play and in more structured situations. For the group as a whole, and for full-terms separately, quantitative measures of inattention at 2 years were predictive of comparable measures at 3.5 years. For preterms separately, quantitative measures of inattention at 1 year were predictive of both behavior and the mothers' rating on the Conners Hyperactivity subscale at 3.5 years. Global, qualitative ratings of attentiveness at 1 and 2 years were predictive of mothers' ratings on the Conners at 3.5 years for the group as a whole and for full-terms separately. For full-terms only, the global ratings of attentiveness at 1 and 2 years were also predictive of 3.5-year quantitative measures of behavior. These data provide an encouraging base for further investigation of early individual differences in attentiveness and of possible early precursors of later attention deficits.

Attention↗
PubMed1990

The usefulness of reaction time tasks in studying attention and organization of behavior in young children.

Three studies explored reaction time procedures as a means of assessing sustained attention and response organization in preschoolers. In the first study, an auditory reaction time task was administered to 65 3.5-year-olds. Performance deteriorated over trials, paralleling results reported for older children and adults. Performance on the task was also related to the hyperactivity subscale of the Conners Parents' Questionnaire and to Stanford-Binet IQ. In a second cross-sectional study, performance on a visual reaction time task improved significantly from 2.5 to 4.5 years. A third study demonstrated individual stability and reasonable test-retest reliability for all measures. The results suggest that reaction time tasks can be usefully employed with young children to measure developmental changes and individual differences in sustained attention and organization of behavior.

Attention↗