Subtypes of aggression in children with attention deficit hyperactivity disorder: medication effects and comparison with typical children.

We examined aggressive behavior in 6- to 12-year-old children, including 20 children with attention deficit hyperactivity disorder (ADHD) on stimulant medication, 19 children with ADHD on placebo (n = 19), and 32 controls. Children completed a laboratory provocation task designed to measure hostile, instrumental, reactive, and proactive aggression. Children in the ADHD-placebo group exhibited increased proactive and reactive aggression following high levels of provocation compared to controls.

Social information processing in elementary-school aged children with ADHD: medication effects and comparisons with typical children.

Examined social information processing (SIP) in medicated and unmedicated children with ADHD and in controls. Participants were 75 children (56 boys, 19 girls) aged 6-12 years, including 41 children with ADHD and 34 controls. Children were randomized into medication conditions such that 20 children with ADHD participated after receiving placebo and 21 participated after receiving methylphenidate (MPH).

Vectorial sequence of mineralization in the turkey leg tendon determined by electron microscopic imaging.

Turkey leg tendons were used as a model tissue to study the spatial and temporal relationships of mineral deposition between matrix vesicles and collagen fibrils by various electron microscopic techniques--bright field, selected-area dark field (SADF), and electron spectroscopic imaging (ESI). These latter imaging techniques enabled the direct localization and spatial distributions of both apatite crystals and atomic elements (Ca, P) within matrix vesicles and collagen. In longitudinal planes of section, a consistent vectorial gradient of mineralization was observed which started with the first localization of apatite mineral in matrix vesicles; with further development, the mineral spread from the vesicle to the extravesicular interstices and then into the adjacent collagen fibrils.

Spectral processing for parallel recording of elemental maps.

Seven different one-, two-, or three-parameter analytic expressions were tested for their applicability to electron energy-loss spectral processing for mapping of atomic distributions in images of magnesium oxide crystals. Two-point two-parameter fits all provided indistinguishable results. Fine structure in the spectrum produced major quantitative inconsistencies for any given expression.