Developmental Validation of the PrepFiler™ Forensic DNA Extraction Kit for Extraction of Genomic DNA from Biological Samples*

Abstract: The PrepFiler? Forensic DNA Extraction Kit enables isolation of genomic DNA from a variety of biological samples. The kit facilitates reversible binding of DNA with magnetic particles resulting in high DNA recovery from samples with very low and high quantities of biological materials: 0.1 and 40 μL of human blood (donor 2) provided 14 and 2883 ng of DNA, respectively. Following the revised SWGDAM guidelines, performance of the developed method was investigated using different sample types including saliva on swabs, semen stains on cotton fabric, samples exposed to environment, samples with polymerase chain reaction (PCR) inhibitors, blood stains (on denim, cotton cloth, and FTA^® paper), and touch evidence‐type samples. DNA yields for all samples tested were equal or better than those obtained by both phenol–chloroform extraction and commercial kits tested. DNA obtained from these samples was free of detectable PCR inhibitors. Short tandem repeat profiles were complete, conclusive, and devoid of PCR artifacts.     

Practical Aspects of Analyzing Vegetable Oils in Fire Debris*

Abstract: Vegetable oils undergo burning, self‐heating, and spontaneous ignition, resulting in their presence in fire debris. As these processes can affect the fatty acid content of vegetable oils, it is important that debris be properly handled in order to obtain reliable and informative data. This research investigated changes in vegetable oil content as a result of storage conditions and different types of burning. Material spiked with vegetable oils and burned was stored under various long‐term conditions, and debris was tested by heating overnight using passive headspace concentration. Results indicated that refrigeration is ideal for fire debris samples suspected of containing vegetable oils and that including passive headspace concentration in the analytical scheme would not affect oils. Spontaneous ignition experiments were conducted to compare the effects of various burning processes on vegetable oil content. Vegetable oils that experienced nonpiloted ignition, self‐heating, and spontaneous ignition produced noticeably different chromatograms from those that underwent piloted ignition.     

Measurement of teen dating violence attitudes: an item response theory evaluation of differential item functioning according to gender

Accurate assessment of attitudes about intimate partner violence is important for evaluation of prevention and early intervention programs. Assessment of attitudes about cross-gender interactions is particularly susceptible to bias because it requires specifying the gender of the perpetrator and the victim. As it is likely that respondents will tend to identify with the same-gender actor, items and scales assessing attitudes about intimate partner violence may not have equivalent measurement properties for male and female respondents. This article examines data from 2,575 high school students who participated in a teen-dating violence intervention study. The majority of participants were Latino (91%), and the sample was nearly evenly split with respect to gender (51% female). Items from two scales (boy-on-girl violence, 4 items; girl-on-boy violence, 5 items) reflecting teens' attitudes about dating violence were calibrated with the graded item response theory (IRT) model and evaluated for differential item functioning (DIF) by gender. A total of three items, two from the girl-on-boy violence scale and one from the boy-on-girl violence scale, were identified as functioning differently for girls and boys. In all cases where DIF was detected, the item's attitudinal statement was easier to accept for the gender group that was portrayed as victim rather than perpetrator. For both scales, accounting for the identified DIF influenced inferences about the magnitude of mean differences in attitudes between boys and girls. These results support the use of IRT scores that account for DIF to minimize measurement error and improve inferences about gender differences in attitudes about dating violence.     

Detection and quantification of low levels of benzoylecgonine in equine urine

Cocaine (COC) is a highly addictive plant alkaloid expressing strong psychostimulatory effect. It has no medical use in equine veterinary practice. The contamination of the environment with cocaine such as its presence on the US paper currency has been reported few times. There are anecdotal reports of low benzoylecgonine (BE) concentrations (usually much less than 100 ng/mL) being found in urine of race horses. In order to protect horsemen against harsh penalties associated with the presence of trace amounts of BE in horse urine as a result of environmental contamination, in February 2005 the Illinois Racing Board issued new medication rules that established the threshold level of 150 ng/mL for BE in equine urine. The penalties associated with this rule provide for increasing fines ($250, $500, $1000) with successive positive reports against a trainer for levels of BE below 150 ng/mL. A total of 19,315 urine samples were collected over the 2-year period of time from winning horses (both harness and thoroughbred) at race tracks in Illinois for routine drug screening (ELISA). The presence of BE was confirmed by GC/MS in 28 urine samples (0.14%). The concentration range for BE in harness horses (21 detections) was < 5-91 ng/mL, and for thoroughbred (seven detections) was 7-52 ng/mL. To date, the laboratory has not reported concentrations of BE that exceed the established threshold concentration of 150 ng/mL.     

Factors Associated with Separation and Ongoing Violence among Women with Civil Protective Orders

This study examined a large sample of women recruited out of court at the time they received a civil protective order to better understand relationship status after obtaining a protective order (PO) and factors associated with protective order violations. Results are consistent with prior research suggesting that the protective order may be the impetus in separating from the abusive partner for some women, while for other women it is part of the separation process. Results also indicated that five out of ten women who did not continue a relationship experienced a violation while seven out of ten women who did continue a relationship with the PO partner experienced a violation. The majority of women felt safer and reported they believed the protective order was effective 13 months post-PO, regardless of relationship status. Furthermore, stalking played a significant role in separation from an abusive relationship and in protective order violations regardless of relationship status. Implications for practice and future research are discussed.

Reciprocal Relationships between Trajectories of Depressive Symptoms and Screen Media Use during Adolescence

Adolescents are constantly connected with each other and the digital landscape through a myriad of screen media devices. Unprecedented access to the wider world and hence a variety of activities, particularly since the introduction of mobile technology, has given rise to questions regarding the impact of this changing media environment on the mental health of young people. Depressive symptoms are one of the most common disabling health issues in adolescence and although research has examined associations between screen use and symptoms of depression, longitudinal investigations are rare and fewer still consider trajectories of change in symptoms. Given the plethora of devices and normalisation of their use, understanding potential longitudinal associations with mental health is crucial. A sample of 1,749 (47% female) adolescents (10–17 years) participated in six waves of data collection over two years. Symptoms of depression, time spent on screens, and on separate screen activities (social networking, gaming, web browsing, TV/passive) were self-reported. Latent growth curve modelling revealed three trajectories of depressive symptoms (low-stable, high-decreasing, and low-increasing) and there were important differences across these groups on screen use. Some small, positive associations were evident between depressive symptoms and later screen use, and between screen use and later depressive symptoms. However, a Random Intercept Cross Lagged Panel Model revealed no consistent support for a longitudinal association. The study highlights the importance of considering differential trajectories of depressive symptoms and specific forms of screen activity to understand these relationships.     

The Influence of Maternal Acculturation,Neighborhood Disadvantage,and Parenting on Chinese American Adolescents’ Conduct Problems: Testing the Segmented Assimilation Hypothesis

Associations among neighborhood disadvantage, maternal acculturation, parenting and conduct problems were investigated in a sample of 444 Chinese American adolescents. Adolescents (54% female, 46% male) ranged from 12 to 15 years of age (mean age = 13.0 years). Multilevel modeling was employed to test the hypothesis that the association between maternal acculturation and adolescents’ conduct problems could be explained by differences in mothers’ reliance on monitoring and harsh discipline. In addition, guided by segmented assimilation theory, measures of neighborhood disadvantage were expected not only to be related to differences in parenting, but also to moderate the effects of maternal acculturation on parenting. Results indicated that increased maternal acculturation was related to higher levels of maternal monitoring and lower levels of harsh discipline, which, in turn, were related to lower levels of adolescents’ conduct problems. Hierarchical linear modeling results revealed that neighborhood disadvantage was related to lower levels of maternal monitoring. However, neighborhood disadvantage did not moderate the link between maternal acculturation and parenting practices.

Longitudinal Effects of Perceived Maternal Approval on Sexual Behaviors of Asian and Pacific Islander (API) Young Adults

Data were obtained from the National Longitudinal Study of Adolescent Health to examine the longitudinal association between Asian and Pacific Islander (API) adolescents’ perceptions of maternal approval of their sexual activity and contraception use, and four sexual outcomes during young adulthood. The study includes a nationally representative sample of 1,195 API adolescents. Logistic regression analyses were used to estimate the associations between predictors (Wave I) and outcomes (Wave III), controlling for covariates. API adolescents who perceived that their mothers approved of their sexual activities were more likely to have engaged in sex before age 15, contracted HIV/Sexually Transmitted Diseases, had multiple sex partners, and paid money for sex during young adulthood. Findings highlight the need for parent–adolescent communication and parental involvement in preventing negative sexual health outcomes among API adolescents transitioning to young adulthood.