The Impact of Biology on Risk Assessment--workshop of the National Research Council''s Board on Radiation Effects Research. July 21-22, 1997, National Academy of Sciences, Washington, DC

Cholinesterases exhibit functions apart from their esterase activity. We have demonstrated an aryl acylamidase and a zinc stimulated metallocarboxypeptidase activity in human serum butyrylcholinesterase. To establish the presence of zinc binding sites in the enzyme we examined the effect of metal chelators on its catalytic activities. The metal chelators 1,10-phenanthroline and N,N,N',N'-tetrakis (2-pyridyl methyl)ethylene diamine (TPEN) inhibited all the three catalytic activities in the enzyme. However, EDTA inhibited the peptidase activity exclusively without affecting the cholinesterase and aryl acylamidase activities. The catalytic activities were recovered upon removal of the chelator by Sephadex G-25 chromatography. Pre-treatment of the enzyme with any one of the three chelators resulted in the binding of the enzyme to a zinc-Sepharose column or to 65Zn2+. Histidine modification of the enzyme pretreated with chelators resulted in abolition of 65Zn2+ binding and zinc-Sepharose binding. Whereas the binding studies demonstrated removal of a metal from a Zn2+ binding site, attempts to remove the metal responsible for catalytic activity were unsuccessful. Atomic absorption spectroscopy indicated approximately 2.5 mol of zinc per mol of enzyme before treatment with EDTA and 1 mol zinc per mol enzyme after EDTA treatment. The results indicate that there are at least two metal binding sites on butyrycholinesterase. The presence of two HXXE...H sequences in butyrylcholinesterase supports these findings. Our studies implicate a zinc dependent metallocarboxypeptidase activity in the non-cholinergic functions of butyrylcholinesterase.     

LD7-5,LD7-6合金棒材工艺研究

LD7－5、LD7－6合金棒材是航空新型发动机的重要材料之一，由于其特殊用途，材料对性能和低倍组织指标有较高要求，作者在对LD7－5、LD7－6两合金的特性进行了全面分析后，从化学成份、挤压温度，淬火时效制度等方面作了较为全面的试验研究，最终确定了生产这两种合金棒材的最佳工艺制度。     

Minutes of the annual business meeting Calgary, Alberta, 7 June 1968.

Presents the minutes of the Annual Business Meeting of the Canadian Psychological Association. The meeting was held on June 7, 1968. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Arthur Allen Ward, Jr., M.D. 1916-1997

Our understanding of the regulatory mechanisms controlling the glucose response in yeast has advanced in the past year. Two transporter-like proteins have been shown to function as glucose sensors in a pathway for glucose induction of transporter genes. Our understanding of the glucose repression mechanism has been augmented by studies of the Snf1 protein kinase, the Mig1 repressor, and the role of Snf1 in inhibiting Mig1 and regulating activators. DNA microarrays have been used to assess glucose-regulated gene expression.     

Single parenthood and school readiness in White, Black, and Hispanic 6- and 7-year-olds.

The aim of this research was to examine the circumstances under which single parenthood may or may not represent an adverse influence on school readiness and achievement in 6–7-year-old children of White, Black, and Hispanic families in a large national survey (NLSY). Home visits provided measures of maternal and family characteristics and of children's vocabulary, math, reading, and behavior problems. Single parenthood was essentially unrelated to the child outcomes in all ethnic groups, and it did not interact with maternal education, ability level, or employment or with poverty status or child gender. Although single- and 2-parent families differed in income, they were very similar in maternal ability and education levels, thus suggesting that in the presence of positive maternal or family characteristics supportive of children's development, single parenthood as such need not represent a risk factor for these early child outcomes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relationship between competitiveness and empathy in 6- and 7-year-olds.

Tested the proposition that competitiveness and a competitive instructional set would suppress the expression of empathy in 6- and 7-yr-old children. The Feshbach and Roe test of empathy was administered to 84 Ss while they were preparing either to compete or to cooperate with another child on a game. Boys rated by teachers as highly competitive were less empathic than less competitive boys; no difference was found for girls. There was no evidence that the Ss' empathy was influenced by the manipulation of instructional set. (9 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)