Preparation and Properties of Novel Aromatic Polyimides from 5,7-Diamino-1,1,4,6-Tetramethylindan and Aromatic Tetracarboxylic Dianhydrides

Novel aromatic polyimides containing indan structure units were prepared from 5,7-diamino-1,1,4,6-tetramethylindan and various aromatic tetracarboxylic dianhydrides. The glass transition temperatures ( Tg’s) of these polyimides were not observed by differential scanning calorimetry at a temperature lower than 500 °C and the 5% weight loss temperatures ( Td5’s) of them were above 422 and 474 °C in air and nitrogen, respectively. Polyimide prepared from 5,7-diamino-1,1,4,6-tetramethylindan and 2,2-bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride was soluble in organic solvents such as tetrahydrofuran, cyclopentanone, chloroform, acetone, ethyl acetate, N-methyl-2-pyrrolidinone and cresol at 20 wt% concentration at ambient temperature. The other resulting polyimides obtained from this diamine possessing an indan structure were also soluble in several organic solvents. These results indicated that polymer properties such as thermal behaviour and solubilities were influenced by the indan structure unit in a repeating structure.

Parenting and Family Support in Japan for 6- to 8-year-old Children Weighing under 1000 Grams at Birth

The purpose of this study was to explore the variables related to paternal involvement in the caregiving of 6- to 8-year-old extremely low-birthweight (ELBW) children, specifically, sociodemographic factors related to the family or individual biological factors related to ELBW. Thirty-three children with a mean birthweight of 845.5 grams and a mean gestational age of 27.4 weeks participated in this research. Approximately 29% of their fathers were classified by the mothers as nonco-operative in overall child care. The paternal involvement in caregiving was related to the sociodemographic variables of the family; the co-operative fathers were proportionally more often from families where the child had no older female sibling(s) and/or grandparent(s), whereas the nonco-operative fathers were proportionally more often from families where the child had older female sibling(s) and/or grandparent(s). The individual perinatal risk variables and IQ, and the paternal variables (age, socioeconomic status) were not related to the paternal co-operativeness. Our sample mothers seemed to have raised their children in more difficult parenting and economic situations, and to have received proportionally more support from grandparent(s) than did typical Japanese mothers. The children's relationships with peers differed between the paternal co-operative and nonco-operative groups; there were proportionally more children from the nonco-operative group who preferred to play alone than to play with peer(s) at the ages of 3-5 years. Thus, scarce paternal involvement in the process of caregiving appeared to influence the children's sociability.

Acid-catalyzed rearrangement of ethynylcycloheptatriene to phenylallene

7-Ethynylcycloheptatriene (1) cleanly isomerizes to phenylallene in the presence of acid. A mechanism involving the protonation of ethynylnorcaradiene, which is in equilibrium with 1, followed by the cleavage of a three-membered ring to give an arenium ion, is proposed. The rearrangement is accelerated by a factor of 370 by introducing tert-butyl groups on C-2 and C-5, indicating the importance of the equilibrium concentration of the norcaradiene form as a rate-controlling factor.

Plasma factor triggering alternative complement pathway activation by liposomes

Several plasma components, such as complement (C) components, play a role in the clearance of liposomes from the circulation. The interactions between liposomes and the C system were investigated in this study. Multilamellar vesicle (MLV) liposomes, which were damaged by activation of the complement, became susceptible depending on the density of cetylmannoside (Man) on the liposome membrane, and activation proceeded through the alternative C pathway as observed for liposomes without Man (PC-MLV) (K. Funato et al., Biochim. Biophys. Acta 1103:198-204, 1992). In addition, the capacity of Man-modified liposomes (Man-MLV) to activate the alternative C pathway was abolished by preadsorption of plasma with Man-MLV but not with PC-MLV. The results suggest that a specific plasma factor adsorbed with Man-MLV was responsible for the augmentation of the C activation and, further, that the rapid clearance of Man-MLV from the circulation is caused by both enhanced C-mediated liposome permeability and enhanced C-mediated phagocytosis of liposomes.