Cumulative Trauma,Personal and Social Resources,and Post-Traumatic Stress Symptoms Among Income-assisted Single Mothers

Data from 247 single mothers were used to partially validate a theoretical model that highlights the process through which post-traumatic stress disorder (PTSD) develops among women. Structural equation modeling was used to assess the direct and indirect relationship between cumulative trauma (CT) and mothers’ PTSD symptom severity. Additionally, we examined the meditational role played by mothers’ strains and resources and the moderating role played by mothers’ residence in an intersectionally advantaged versus disadvantaged neighborhood. A good fit was found between the hypothesized model and data. Mothers’ strains and personal resources played a significant mediating role in the relationship between CT and PTSD symptom severity. Neighborhood of residence did not moderate the CT-PTSD process. Implication for practice and treatment are discussed.     

Trace DNA: a review,discussion of theory,and application of the transfer of trace quantities of DNA through skin contact

Advances in STR PCR DNA profiling technology allow for the analysis of minute quantities of DNA. It is frequently possible to obtain successful DNA results from cellular material transferred from the skin of an individual who has simply touched an object. Handling objects, such as weapons or other items associated with a crime, touching surfaces, or wearing clothing, may represent sufficient contact to transfer small numbers of DNA bearing cells, or trace DNA, which can be successfully analyzed. With this minimal amount of contact required to yield a suspect profile comes tremendous crime solving potential, and a number of considerations for prudent application, and the maximization of evidentiary value. Evidentiary materials not previously considered must be recognized and preserved, and the resulting DNA type profiles interpreted in their proper forensic context.     

Isotopic analogs as internal standards for quantitative GC/MS analysis--molecular abundance and retention time difference as interference factors

The following analyte/isotope-labeled internal standard (IS) systems are adapted to further study the interference phenomenon previously reported from our laboratory--the intensity ratio of the ion-pair designated for a specific analyte/2H-analog system increases as the solvent used to reconstitute the extraction/derivatization residue is increased: (a) Three analyte/2H-analog pairs with 2H-atoms positioned at allylic sites (butalbital, secobarbital, methohexital); (b) Two analyte/2H-analog pairs without these structural features (pentobarbital, phenobarbital); and (c) Two analyte/13C-analog pairs (butalbital, secobarbital). Major experimental parameters adapted in this study include: (a) Varying reconstitution solvent volume while keeping a constant analyte/IS concentration ratio; (b) Varying analyte/IS concentration ratio; (c) Varying gas chromatograph (GC) injection port temperature; and (d) Varying GC column temperature programming conditions, rendering difference in the degree of overlap of the peaks derived from the analyte and the 2H-analog. This study results in the following observations: (a) Changes in the intensity ratio of the ion-pair designated for a specific analyte/2H-analog system depend on molecular abundance, regardless of whether the 2H-atoms are positioned at active allylic positions or not--thus, ruling out hydrogen/deuterium exchange as the cause of the observed interference phenomenon; (b) Variations in GC injection port temperature do not alter the observed interference phenomenon-thus, ruling out chemical reactions at the injection port as the underlying cause; (c) Variations in peak-overlapping between the analyte and the 2H-analog, facilitated by changing GC column programming conditions, alter the observed interference phenomenon. Abundance of the analyte and the 2H-analog and their overlapping characteristic in the mass spectrometer ion source are believed to be the underlying cause of the observed interference phenomenon. The interference phenomenon observed for a specific analyte/2H-analog system has significant consequences on the linearity of the thereby generated calibration curves. Nonlinear approaches can better describe the calibration data and are needed more in comparison to systems in which 13C-analogs are used as the ISs.