Mechano-chemischer abbau bei der schwingmahlung von poly(ε-caprolactam) in gegenwart von sebacoylchlorid und nachfolgende polykondensation mit aromatischen diaminen

Mechano-chemical degradation of poly(ε-caprolactam) {poly[imino(1-oxohexamethylene)]} in the presence of sebacoyl chloride, carried out by vibratory milling, gave polyamide acid chlorides. Subsequently, these products, also by vibratory milling, were condensed with p-phenylenediamine to obtain polymers with aromatic amino groups which by diazotation and coupling reaction were transformed into coloured polymers. The use of some specially selected coupling components (i.e. containing itself primary amino groups) allowed to regulate the colour intensity of the final product when the diazotation and coupling reaction was carried out gradually.     

A longitudinal twin study on IQ, executive functioning, and attention problems during childhood and early adolescence

Variation in human behavior may be caused by differences in genotype and by non-genetic differences ("environment") between individuals. The relative contributions of genotype (G) and environment (E) to phenotypic variation can be assessed with the classical twin design. We illustrate this approach with longitudinal data collected in 5 and 12-year-old Dutch twins. At age 5 data on cognitive abilities as assessed with a standard intelligence test (IQ), working memory, selective and sustained attention, and attention problems were collected in 237 twin pairs. Seven years later, 172 twin pairs participated again when they were 12 years old and underwent a similar protocol. Results showed that variation in all phenotypes was influenced by genetic factors. For IQ the heritability estimates increased from 30% at age 5, to 80% at age 12. For executive functioning performance genetic factors accounted for around 50% of the variance at both ages. Attention problems showed high heritabilities (above 60%) at both ages, for maternal and teacher ratings. Longitudinal analyses revealed that executive functioning during childhood was weakly correlated with IQ scores at age 12. Attention problems during childhood, as rated by the mother and the teacher were stronger predictors (r = -0.28 and -0.36, respectively). This association could be attributed to a partly overlapping set of genes influencing attention problems at age 5 and IQ at age 12. IQ performance at age 5 was the best predictor of IQ at age 12. IQ at both ages was influenced by the same genes, whose influence was amplified during development.     

Heritability of Selective Attention and Working Memory in Preschoolers

In this study aspects of selective attention and working memory were tested in a large sample of nearly 6-year old monozygotic and dizygotic twin pairs, using a computerized test battery (Amsterdam Neuropsychological tasks). In the selective attention task the presence of a foil signal (target signal at an irrelevant location) resulted in more false alarms than a non-target signal. In the working memory task an increase in memory load lead to an increase in response times and errors. We analyzed variations in absolute performance parameters (overall speed and accuracy) and relative performance parameters (increase in errors and/or reaction time). The results showed clear familial resemblances on performance. It proved difficult to ascribe these effects to shared genes or to shared environment. An exception was memory search rate, which was clearly heritable.     

Exploring the functional role of the CHRM2 gene in human cognition: results from a dense genotyping and brain expression study

Background  

The CHRM2 gene, located on the long arm of chromosome 7 (7q31-35), is involved in neuronal excitability, synaptic plasticity and feedback regulation of acetylcholine release, and has been implicated in higher cognitive processing. The aim of this study is the identification of functional (non)coding variants underlying cognitive phenotypic variation.     

Structure, function, and levels of neutrophil elastase after laparoscopic cholecystectomy

Neutrophil elastase is a neutral proteinase present mainly in the azurophilic granules of segmented granulocytes, the main cells involved in the inflammatory response reaction. In our study we attempted to determine whether an enzyme such as neutrophil elastase produced by polymorpho-nuclear leukocytes could be an indicator capable of determining the degree of surgical trauma, comparing two surgical approaches, namely, laparoscopic cholecystectomy and open cholecystectomy. Plasma neutrophil elastase was determined photometrically, using an immune-activation immunoassay, in 66 patients (32 patients underwent open cholecystectomy and 34 laparoscopic cholecystectomy) 1 day before surgery and 1, 3, 6 and 12 days after surgery. We established a reference range for elastase by measuring the serum elastase concentration in 48 healthy control patients. A significant increase (p < 0.05) in plasma neutrophil elastase levels was observed on days 1, 3 and 6 after surgery in patients undergoing open cholecystectomy, whereas the levels of the enzyme were almost stable in patients undergoing laparoscopic cholecystectomy. We recorded two cases (6.2%) of respiratory tract infections in the "open" group. Neutrophil elastase is a good indicator for discriminating the severity of the surgical trauma, which is certainly more severe in laparotomy than in laparascopic cholecystectomy. Peripheral leukocyte function seems to be better preserved after laparoscopic surgery than after laparotomy.     

The ongoing adaptive evolution of ASPM and Microcephalin is not explained by increased intelligence

Recent studies have made great strides towards identifying putative genetic events underlying the evolution of the human brain and its emergent cognitive capacities. One of the most intriguing findings is the recurrent identification of adaptive evolution in genes associated with primary microcephaly, a developmental disorder characterized by severe reduction in brain size and intelligence, reminiscent of the early hominid condition. This has led to the hypothesis that the adaptive evolution of these genes has contributed to the emergence of modern human cognition. As with other candidate loci, however, this hypothesis remains speculative due to the current lack of methodologies for characterizing the evolutionary function of these genes in humans. Two primary microcephaly genes, ASPM and Microcephalin, have been implicated not only in the adaptive evolution of the lineage leading to humans, but in ongoing selective sweeps in modern humans as well. The presence of both the putatively adaptive and neutral alleles at these loci provides a unique opportunity for using normal trait variation within humans to test the hypothesis that the recent selective sweeps are driven by an advantage in cognitive abilities. Here, we report a large-scale association study between the adaptive alleles of these genes and normal variation in several measures of IQ. Five independent samples were used, totaling 2393 subjects, including both family-based and population-based datasets. Our overall findings do not support a detectable association between the recent adaptive evolution of either ASPM or Microcephalin and changes in IQ. As we enter the post-genomic era, with the number of candidate loci underlying human evolution growing rapidly, our findings highlight the importance of direct experimental validation in elucidating their evolutionary role in shaping the human phenotype.