Use of a commercially available hydrogel as a novel DNA surface sampling tool.

A common requirement in the military, law enforcement, and forensic mission space is the need to collect trace samples from surfaces using a method that not only readily captures the sample but also retains its integrity for downstream identification and characterization. Additionally, collecting samples from three-dimensional objects (e.g.

Use of RGB values in the Periodic Acid-Schiff color test to determine the presence of vaginal fluid.

This study demonstrates how RGB color values from microscopic smears stained with the Periodic Acid-Schiff reagent under standardized microscopy conditions can be used to indicate the presence of vaginal secretions. Based on data obtained in the study, a numeric threshold determined from the sum of separate values for red, blue and green was determined to differentiate vaginal-based samples with other body fluids. Using this threshold, 55 of 57 vaginal-based samples tested positive for the presence of vaginal secretion.