On the Fourier transformation on spaces of (p,q)-multipliers

LetG denote a locally compact abelian topological group. The aim of the present paper is to prove an “intermediate” result between two well-known results ofL. Hörmander andG. I. Gaudry concerning the structure of the spaces ?_G?μ?t ^p,q (G).     

Narrow band quantitative and multivariate electroencephalogram analysis of peri-adolescent period

ABSTRACT: BACKGROUND: The peri-adolescent period is a crucial developmental moment of transition from childhood to emergent adulthood. The present report analyses the differences in Power Spectrum (PS) of the Electroencephalogram (EEG) between late childhood (24 children between 8 and 13 years old) and young adulthood (24 young adults between 18 and 23 years old). RESULTS: The narrow band analysis of the Electroencephalogram was computed in the frequency range of 0--20 Hz. The analysis of mean and variance suggested that six frequency ranges presented a different rate of maturation at these ages, namely: low delta, delta-theta, low alpha, high alpha, low beta and high beta. For most of these bands the maturation seems to occur later in anterior sites than posterior sites. Correlational analysis showed a lower pattern of correlation between different frequencies in children than in young adults, suggesting a certain asynchrony in the maturation of different rhythms. The topographical analysis revealed similar topographies of the different rhythms in children and young adults. Principal Component Analysis (PCA) demonstrated the same internal structure for the Electroencephalogram of both age groups. Principal Component Analysis allowed to separate four subcomponents in the alpha range. All these subcomponents peaked at a lower frequency in children than in young adults. CONCLUSIONS: The present approaches complement and solve some of the incertitudes when the classical brain broad rhythm analysis is applied. Children have a higher absolute power than young adults for frequency ranges between 0-20 Hz, the correlation of Power Spectrum (PS) with age and the variance age comparison showed that there are six ranges of frequencies that can distinguish the level of EEG maturation in children and adults. The establishment of maturational order of different frequencies and its possible maturational interdependence would require a complete series including all the different ages.     

Zeta Potential as an Analytical Tool for Graft Copolymers and for Polymer Surfaces

Polymers with electrically charged groups exhibit a zeta potential when in contact with electrolyte solutions in water. This can be measured with solid polymers as fibers, foils, or granulates. The method of streaming potential/streaming current allows the determination of the carboxyl content of cellulose grafted with poly-(acrylic acid). Since zeta-potential measurements concern the surface of the sample, the method yields information on the type of grafting; i.e., whether it takes place mainly on the surface or throughout the bulk. By measuring the pH dependence of the zeta potential it is possible to obtain the pK value of the charged groups. The significance of zeta potential as an analytical tool is emphasized.     

The 48 bp centromeric repeat is a functionally conserved motif in great apes and man showing protein-binding properties

The centromere-kinetochore complex is a chromosomal assembly site including repeat motifs and protein binding properties thus mediating chromosome motility and mitotic regulation. Next to the alpha-satellite DNA family as well as human satellite III DNA, contribution of other repetitive sequences has to be strongly considered in centromere function. Here, we report the identification of centromeric 48 bp motifs, isolated from chimpanzee and orang-utan using an orthologous human DNA probe. Applying Southern hybridization we show that these sequences are restricted to hominoid species. Diminishing hybrid formation in gibbons suggested that the 48 bp repeat originated approximately 25-20 million years ago. Consistently, both chimpanzee as well as human repeat probes failed to generate any hybridization signal with the monkey species Cercopithecus aethiops and Aotes trivirgatus. Sequence deviations from the consensus of human repeat monomers of 6% and 10.4% in chimpanzee and orang-utan, respectively, were found within a 16 bp region of the 48 bp repeat units. Gel mobility shift assays using chimpanzee repeat dimers as probes revealed peptide-binding properties with human and chimpanzee nuclear extracts. Species-specific DNA-protein complexes remained unaffected by competition studies and indicated the presence of at least one novel interacting protein consisting of two subunits with 90 and 95 kDa. Our data suggest that the 48 bp repeat, next to alpha-satellite DNA, provides essential sequence information for specific DNA-protein interaction and they imply phylogenetic conservation of these binding properties in primates. The complex is likely involved in the proper formation and/or function of mammalian centromeres.