Lipid analysis by quantitative thin-layer chromatography

Techniques for the quantitative analysis of lipids using thin-layer chromatography (TLC) are reviewed. The general procedures are divided into two groups on the basis of whether or not the methods involve the recovery of substances from chromatoplates. Recovery methods are elaborated under detection of spots, recovery of substances and quantification. Methods are described for the recovery of labile compounds from chromatoplates and for the determination of the structures of triglycerides and lecithins. Methods for the direct quantitative analysis of spots on chromatoplates are reviewed. These include measurements of spot size, reflectance, absorbance of transmitted light, and fluorescence. Details of the photodensitometric method, particularly, spot visualization and instrumentation are described. The analysis of lipid classes using a combination of DEAE cellulose chromatography and TLC by the densitomery of charred spots is illustrated.     

Early number skills: Examining the effects of class-wide interventions on kindergarten performance.

The purpose of this study was to use multilevel modeling to compare the effects of KPALS alone and combined with goal setting and reinforcement to a control condition on early numeracy performance of 96 kindergarteners. Demographic variables were examined as moderators. Results differed according to early numeracy measure, with both versions of KPALS outperforming the control group for number identification, while KPALS plus goal setting and reinforcement improved performance on missing number and the TEMA-3. Demographic variables, but not treatment, accounted for performance on a measure of quantity discrimination. Posttest differences were found for TEMA-3 and NI, but no differences persisted at 4 months follow-up. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Examining a classwide application of cover-copy-compare with and without goal setting to enhance mathematics fluency.

The purpose of this study was to compare the effects of cover-copy-compare alone and combined with two forms of goal setting to a control condition on the mathematics fluency of 173 third-grade students. Treatment sessions occurred twice weekly for a total of 6 weeks, and multilevel modeling was used to examine progress across intervention sessions. Results suggested that combining cover-copy-compare with goal setting (problems correct) leads to steeper slopes and higher final scores than most other treatment conditions, the effects of which were retained over 1 month and generalized to similar stimulus conditions. Initial scores on a third-grade general outcome measure significantly affected growth over time but not final score. (PsycINFO Database Record (c) 2010 APA, all rights reserved)