Forensic applications of infrared chemical imaging: multi-layered paint chips

This paper examines the potential of infrared chemical (hyperspectral) imaging as a technique for the forensic analysis of automotive paint chips in particular, and multicomponent (e.g., layered) samples in general. Improved sample preparation procedures for the infrared analysis of paint chips are detailed, with the recommendation that where mounting resins are chemically incompatible with the sample, it is better to mount and section the sample in a soft wax from which the sections can be removed and pressed into a KBr disk for transmission analysis. Infrared chemical images of multilayered paint chips have been successfully obtained, with the chief advantage over conventional infrared analysis being that thousands of infrared spectra are collected in a few minutes across the whole sample, at a spatial resolution of around 5 microm. As with conventional infrared spectroscopy, chemical species can be identified from their spectra, but the wealth of information available can be also extracted in a number of different ways that make multicomponent spectral (and hence chemical) comparisons between two samples easy to visualize and understand. In one approach, the infrared chemical images of two paint chips being compared side-by-side can be viewed as a "movie," in which each frame is an intensity map of the two samples at a given wavenumber (frequency) value. In another approach, the spectra (pixels) in the image files are classified into chemically similar groups, resulting in a "cluster" image that makes it possible to simultaneously compare all of the layers in two paint chips. These methods are applicable to other multicomponent samples, and also to other chemical imaging techniques.     

STR-typing of human DNA from human fecal matter using the QIAGEN QIAamp stool mini kit

The purpose of this study was to compare the effectiveness of the QIAGEN QIAamp Stool Mini Kit against a standard phenolchloroform procedure for the extraction, quantitation, and STR-typing of human nuclear DNA from human feces. Stools from six subjects were sampled by swabbing and excision. Samples extracted with the QIAamp kit gave a wide range of DNA yields, whereas those extracted by the organic method yielded no DNA. DNA was not recovered from one subject's stools by either procedure. The QIAamp extracts were amplified with the Profiler Plus and COfiler kits, and PCR inhibition was observed with DNA extracts that were further concentrated. Substitution of water or TE-4 for the QIAamp elution buffer eliminated most, if not all, of the inhibition. A modified QIAamp procedure was used to extract thirty samples, which were subjected to one of five environmental conditions. DNA was recovered from all of these samples, and typing results were obtained on 93% of the samples.     

Longitudinal Links Between Perceptions of Adolescence and the Social Beliefs of Adolescents: Are Parents’ Stereotypes Related to Beliefs Held About and by Their Children?

This study examined: (1) relations between parents prior stereotypes about adolescence and their later beliefs about their own child during early and middle adolescence, (2) relations between parents stereotypes and their own childs behaviors during middle and late adolescence, and (3) the role of congruency between mothers and fathers beliefs about adolescence in predicting their childs behavior. The results revealed significant relations between parents prior stereotyped beliefs and their specific beliefs about their own children during the 7th and 10th grades. In addition, the relations between parents prior stereotypes and their adolescent childrens behaviors measured at 3 and 5 years later (10th and 12th grades) were estimated. Parents stereotypes about adolescence significantly predicted their childrens behaviors in both 10th and 12th grades. Finally, the congruency between mothers and fathers stereotyped beliefs was significantly related to their childrens behaviors in the 10th and 12th grades. Parents who had consistent and strong stereotypes about adolescence had adolescent children with more deviant peers than parents with consistent, but less-stereotyped views.Portions of this paper were presented at the 2002 biennial meeting of the Society for Research in Adolescence, New Orleans, LA. This research was made possible by grants from NSF, the Spencer Foundation, and the William T. Grant Foundation to Jacquelynne Eccles and Bonnie Barber.Professor of Psychology, and Human Development and Family Studies, Pennsylvania State University. Received PhD in Psychology from the University of Michigan. Current interests include the development of social cognitive processes during childhood and adolescence, and gender differences in achievement motivation, self-perceptions of achievement, and parents influences on achievement.Doctoral Candidate and Research Assistant, Human Development and Family Studies, Pennsylvania State University. Received MS in Human Development and Family Studies from the Pennsylvania State University. Current interests include gender socialization and activity involvement during adolescence.Research Associate, North Carolina Center for Nursing. Received MS in Human Development and Family Studies from the Pennsylvania State University. Current interests include adolescent development.