Lung lamellar bodies lack certain key enzymes of phospholipid metabolism

Palmitoyl CoA-glycerol-3-phosphate acyltransferase, phosphatidate phosphohydrolase, and phospholipase A were assayed in subcellular fractions of rat lung, including lamellar bodies, the putative site of storage and secretion of lung surfactant. The specific activity of each of these enzymes in lamellar bodies was relatively low and could be entirely accounted for by a small contamination of the lamellar bodies fraction by microsomes, as quantitated by the presence of the microsomal marker reduced triphosphopyridine nucleotide cytochromec reductase. These data indicate that lamellar bodies are not the site of synthesis of the lipid component of pulmonary surfactant by pathways involving these enzymes.     

Effect of pH on the precipitation of hydroxyapatite on silica gels

Silica-HAp composites have been produced with particle size ranging from several nm to few μm, through control of the pH of the solution, which also controls morphology. A calcium ions reservoir has been made available as a Ca/EDTA soluble complex allowing the production of HAp at low temperature and short periods of time (hours). The presence of silica seems to promote the formation of HAp under these conditions. Electronic Publication     

Synthesis of zirconium tungstate–zirconia core–shell composite particles

In this work, ZrW₂O₈–ZrO₂ core–shell composite particles were synthesized. ZrW₂O₈ that was used in the core is a material with negative coefficient of thermal expansion, and it was synthesized from a high-pH precursor based on use of tungstic acid and zirconium acetate. Shell layer was composed of ZrO₂ nanocrystallites and precipitated from an aqueous solution by urea hydrolysis. While volume of the shell was effectively controlled by the initial zirconium ion concentration in the solutions, the rate of precipitation was a function of the ratio of initial concentrations of urea to zirconium ions. It is hypothesized that isolation of the ZrW₂O₈ within a layer of ZrO₂, will be a key element in solving problems associated with reactivity of ZrW₂O₈ towards other components in sintering of ceramic–ceramic composites with tuned or zero thermal expansion coefficient.     

Co-occurrence of depressive symptoms and antisocial behavior in adolescence: A common genetic liability.

Recent reviews of research on child and adolescent psychopathology have highlighted the consistently high rates of co-occurring dimensions of psychopathology, particularly between internalizing and externalizing disorders, and have suggested that further research examining the causes of co-occurring syndromes is needed. The authors examined this question in a national sample of 720 same-sex adolescent siblings between 10 and 18 years of age consisting of monozygotic and dizygotic twins, full siblings, half siblings, and unrelated siblings. Composite measures of adolescent and parent reports and observational measures of depressive symptoms and antisocial behavior were subjected to behavioral genetic models that examine the genetic and environmental influences on individual differences in each dimension as well as in the co-occurrence between dimensions. Results indicated that approximately half of the variability in depressive symptoms and antisocial behavior is attributed to genetic factors; shared and nonshared environmental influences were also significant. The co-occurrence of depressive and antisocial symptoms was explained by genetic and shared and nonshared environmental influences. Specifically, approximately 45% of the observed covariation between depressive and antisocial symptoms could be explained by a common genetic liability. Results are interpreted in light of contribution of genetic studies to debates on child and adolescent psychopathology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Parents' nonshared treatment of siblings and the development of social competence during adolescence.

This article proposes that there is a distinction between shared (SH) and nonshared (NSH) parenting. This study investigated the contribution of these aspects of parenting to indexes of social competence in adolescents by means of a multimethod, multimeasure study. NSH parenting was predictive of child adjustment at least as strongly as was SH parenting. The NSH components, however, were child-directed relations instead of sibling-directed relations. Parental treatment of a sibling thus added information about SH environmental processes, but did not provide information about independent NSH processes. NSH components predicted social responsibility and cognitive agency rather than autonomy, sociability, and self-worth. NSH conflict, shared monitoring and control, and both SH and NSH warmth were important for the prediction of adjustment. These relations were consistent across gender and were characteristic of a broad array of family types. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Parent ratings of EAS temperaments in twins, full siblings, half siblings, and step siblings.

A twin/family design was used to explore genetic contributions to personality; to evaluate whether twins and nontwins yield different genetic results; and to test for the presence of contrast effects, the tendency of a rater to contrast one sibling with the other, thereby magnifying existing behavioral differences. The sample consisted of 708 adolescent same-sex sibling pairs from 10 to 18 years of age. Pairs included identical (monozygotic; MZ) and fraternal (dizygotic; DZ) twins, and full siblings in nondivorced families; and full, half, and unrelated siblings in stepfamilies. Mothers and fathers rated the temperament of their children on the EAS Temperament Survey (A. H. Buss & R. Plomin, 1984). Model-fitting analyses revealed significant genetic infiuences on each of the four EAS dimensions; however, for some dimensions, heritability estimates were significantly greater for twins than for nontwins. Overall, the data were best described by a sibling interaction model, which indicated significant contrast effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Kinetics of Urea Decomposition in the Presence of Transition Metal Ions: Ni2+

The literature on kinetics of the urea decomposition reaction was reviewed for the 333–373 K range of temperature. Possible reactions in the pH range of 5–9 were identified. Kinetic simulations indicated significant accumulation of the cyanate intermediate in the pH-time–temperature range that was studied. The effects of Ni²⁺ hydrolysis and complexation with the urea decomposition products were incorporated into the simulations. The kinetic simulation of the rate of Ni²⁺ removal from the solutions was compared against the experimental data. The experimental results indicated an agglomerative growth mechanism for the precipitation process. Chemical analyses showed that the composition of the precipitate varies with digestion time, in agreement with the predictions of the kinetic simulation.     

Siblings, family relationships, and child development: Introduction.

Introduces a special section consisting of 4 articles devoted to siblings. The prevalent theme running through the articles is that sibling relationships and their contribution to developmental outcomes can only be understood in the context of processes involved in other family relationships. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Psychopathy and punishment.

An experiment to test the hypothesis that psychopathy is associated with deficient passive avoidance learning under punishment. 75 High Pd and 75 Low Pd female undergraduates, equated for intelligence, learned a list of 10 nonsense syllables under 1 of 3 conditions of reinforcement: verbal reward, verbal punishment, and absence of comment by E. Punishment significantly retarded the learning of Low Pd Ss, but not that of High Pd Ss. No significant differences occurred under reward or neutral conditions. The hypothesis was considered confirmed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Humor preferences in normal and physically handicapped children.

This study investigated the relationship of motor disabilities and humor ratings of activity and nonactivity cartoons by poliomyelitis, cerebral palsy, and normal children. Poliomyelitis children rated activity cartoons as funnier than nonactivity cartoons. They also rated activity cartoons higher than did cerebral palsy or normal children, and nonactivity cartoons lower than did cerebral palsy children. These differences could not be explained on the basis of age of affliction or motor patterns of the particular disabilities involved. (PsycINFO Database Record (c) 2010 APA, all rights reserved)