Detection Of Blood Stains

Blood is composed of liquid plasma and serum with solid components consisting of red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes). Most presumptive tests for blood focus on detecting the presence of hemoglobin molecules, which are found in the red blood cells and used for transport of oxygen and carbon dioxide. A simple immunochromatographic test for identification of human blood is available from Abacus Diagnostics (West Hills, CA) as the ABAcard® HemaTrace® kit. This test has a limit of detection of 0.07 |lg hemoglobin/mL and shows specificity for human blood along with higher primate and ferret blood (Johnston et al. 2003).

Luminol is another presumptive test for identification of blood that has been popularized by the TV series CSI: Crime Scene Investigation. The luminol reagent is prepared by mixing 0.1 g 3-amino-phthalhydrazide and 5.0 g sodium carbonate in 100 mL of distilled water. Before use, 0.7 g of sodium perborate is added to the solution (Saferstein 2001). Large areas can be rapidly evaluated for the presence of bloodstains by spraying the luminol reagent onto the item under investigation. Objects that have been sprayed need to be located in a darkened area so that the luminescence can be more easily viewed. Luminol can be used to locate traces of blood that have been diluted up to 10 million times (Saferstein 2001). The use of luminol has been shown to not inhibit DNA testing of STRs that may need to be performed on evidence recovered from a crime scene (Gross et al.

1999). Demonstration that presumptive tests do not interfere with subsequent DNA testing can be important when making decisions on how biological evidence is processed in a forensic laboratory (Hochmeister et al. 1991, Budowle et al.

Stuttering Simple Techniques to Help Control Your Stutter

Stuttering Simple Techniques to Help Control Your Stutter

Discover Simple Techniques to Help Control Your Stutter. Stuttering is annoying and embarrassing. If you or a member of your family stutters, you already know the impact it can have on your everyday life. Stuttering interferes with communication, and can make social situations very difficult. It can even be harmful to your school or business life.

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