Innocent detections

The iaterpretation of forensic toxicology (18) results is often challenging. Courts frequently ask if an amount of dmg detected ia a specimen could cause a specific type of behavior, ie, would someone be under the influence of a dmg at a specific concentration, would a particular dmg concentration cause diminished capacity, or was the dmg the cause of death In a random employee dmg testing case, a worker screened positive for opiates by EMIT and gc/ms analysis of the urine specimen showed low levels of morphine. Although one possibiUty was that the iadividual was a heroia user, a review of foods eaten ia the prior 24 hours suggested a more innocent cause a poppy-seed bagel. 

The feasibility of the fast neutron bulk activation detection system and of other bulk nitrogen measurement systems is in serious question. The nitrogen present in innocent, common, and completely legitimate materials to be found in suitcases varies sufficiently that the estimated minimum detectable amount of explosive in this system is around 25 to 50 sticks of 40% dyji3=... 

Reporting false-positive results may send an innocent person to prison, so everything possible must be done to avoid such an outcome. Assays with enhanced sensitivity to detect both parent compound and metabolites will allow for detection of drugs over longer periods of time and for more accurate determination of when an individual was first exposed to a chemical. 

The results of this survey led the authors to conclude that traces of high explosives were rare within the general public environment. In fact, no traces of NG, TNT or PETN were detected at any of the public sites sampled during this project. Only four low level traces of RDX were detected. Therefore, they concluded that it was unlikely that a member of the public would be innocently contaminated with a significant quantity of explosives. 

A 2007 paper by Santos and Eberlin provides an excellent example of a non-innocent ESI process that allows detection of otherwise... 

Besides this hapten or penicillin-type of drug-induced hemolysis, a second less frequent mechanism, the so-called innocent bystander mechanism can occur (46,49,50). Penicillin-antibody complexes are only loosely bound to erythrocytes and activate complement, which can be detected on the erythrocyte surface with the complement antiglobulin test ( complement or nongamma type). This mechanism plays a part in immune hemolytic anemias due to various drugs other than penicillins. The hemolytic reaction can continue for weeks after withdrawal of penicillin, that is as long as sufficient penicillin-coated erythrocytes and specific antibodies remain in circulation. 

These days security is at the top of everyone s iist of important concerns, especiaiiy for those peopie who are responsibie for the safety of our transportation systems. In particuiar, airports need speedy and sensitive detectors for expiosives. Piastic expiosives are especiaiiy tricky to detect because they do not respond to metai detectors, and they can be shaped into innocent-iooking objects to avoid X-ray detection. However, a team of scientists at Oak Ridge Nationai Laboratory ied by Thomas Thundat has just pubiished a description of an inexpensive device that is extremeiy sensitive to two N-containing compounds found in piastic expiosives. The key part of this detection device is a tiny (180-micrometer), V-shaped cantiiever made of siiicon. The cantiiever is shown in the accompanying photo next to a human hair for size comparison. 

It is seen that the polarization catastrophe is in fact an innocent artifact, because it is now easily detected and amended. In contrast, there are other artifacts appearing in the adsorption isotherms when is used as the independent electrical variable which are difficult to be identified. Note especially the artifact curve (2) in Figure 18, which does not exhibit any sign of phase transition. However, even these artifacts can be amended either by the use of the generalized ensemble A or the procedure suggested above. At any rate we observe once more that the electrode charge density when it is used as an independent electrical variable, is a difficult variable, which should be handled with much care. 

Zuin L., Innocent R, Fabris D., Lunardon M., Nebbia G., Viesti G., Cinausero M., and Palomba M., Experimental optimisation of a moderated 252Cf source for land mine detection, Nucl. Instrum. Methods Phys. Res., Sect. A, 449(1), 416-426, 2000. 

A wide variety of analytical methods have been applied to the detection and identification of GSR. In common with other forensic analyses they can be divided into color (chemical) spot tests for initial screening and instrumental methods. The situation with GSR is complicated by the issues of contamination and by the fact that many of the chemical components seen in GSR may have other innocent or environmental sources. 

---