Heterogenization of Homogeneous Catalysts: the Effect of the Support

We have studied the influence of placing a soluble, homogeneous catalyst onto a solid support. We determined that such a 'heterogenized' homogeneous catalyst can have improved activity and selectivity for the asymmetric hydrogenation of enamides to amino acid derivatives. The route of heterogenization of RhDuPhos(COD){sup +} cations occurs via electrostatic interactions with anions that are capable of strong hydrogen bonding to silica surfaces. This is a novel approach to supported catalysis. Supported RhDuPhos(COD){sup +} is a recyclable, non-leaching catalyst in non-polar media. This is one of the few heterogenized catalysts that exhibits improved catalytic performance as compared to its homogeneous analog

Young Children’s Self-Concepts: Associations with Child Temperament, Mothers’ and Fathers’ Parenting, and Triadic Family Interaction

This study explored how children’s self-concepts were related to child temperament, dyadic parenting behavior, and triadic family interaction. At age 3, child temperament, mothers’ and fathers’ parenting behavior, and triadic (mother, father, and child) family interaction were observed in the homes of 50 families. At age 4, children’s self-concepts were assessed using the Children’s Self-View Questionnaire (Eder, 1990). Analyses revealed that temperamental proneness to distress and triadic family interaction made independent contributions to children’s self-reported timidity and agreeableness. In contrast, dyadic parenting behavior moderated the associations between child temperament and children’s self-reported timidity and agreeableness such that temperament was only associated with children’s self-concepts when mothers and fathers engaged in particular parenting behaviors. Results suggest both direct and interactive influences of family dynamics and child characteristics on children’s self-concept development

The DNA sequence of the human X chromosome

The human X chromosome has a unique biology that was shaped by its evolution as the sex chromosome shared by males and females. We have determined 99.3% of the euchromatic sequence of the X chromosome. Our analysis illustrates the autosomal origin of the mammalian sex chromosomes, the stepwise process that led to the progressive loss of recombination between X and Y, and the extent of subsequent degradation of the Y chromosome. LINE1 repeat elements cover one-third of the X chromosome, with a distribution that is consistent with their proposed role as way stations in the process of X-chromosome inactivation. We found 1,098 genes in the sequence, of which 99 encode proteins expressed in testis and in various tumour types. A disproportionately high number of mendelian diseases are documented for the X chromosome. Of this number, 168 have been explained by mutations in 113 X-linked genes, which in many cases were characterized with the aid of the DNA sequence