Fingerprint latent

Forensic science laboratories are generally divided into separate specialty areas. These typically include forensic toxicology, soHd-dose dmg testing, forensic serology, trace evidence analysis, firearms and tool mark examination, questioned documents examination, and latent fingerprint examination. Laboratories principally employ chemists, biochemists, and biologists at various degree levels. In some specialty areas, eg, firearms examination, questioned... 

Lasers (qv) and other high intensity or alternative light sources are usefiil in crime laboratories to visualize latent fingerprints, seminal fluid stains, obhterated writings, and erasures, and to aid in specialized photographic work. Infrared and ultraviolet light sources are also used to view items of evidence. 

Since September 1997, the Journal of Chemical Education (JCE) publishes on a regular base a Classroom Activity that is set separately on a distinct hard sheet, including both the student activity (on one side) and instructor information sheet (on the back side). These activities are designed to actively engage students, while the topics covered are usually coimected with everyday life and apphcations (e.g. acid rain, bath bubblers, toothpastes, water filtration, anthocyanins, latent fingerprints, etc.). Liapi and Tsaparlis (2007) have used three of these activities (acid rain, bath bubblers, toothpastes) in conjunction with two conventional laboratory activities (some properties of acids/some properties of bases) with a class of ninth-grade students in Greece. An evaluation by the students showed a very positive result in favour of the JCE Activities they are connected with life and involve creativity on the part of the students (Fig. 5.2). 

Fingering process, 11 763-764 Fingerprints, 12 91 latent, 12 101-102 types of, 12 101 Fining, of wine, 26 317-318 Finings, 3 584 Finishes... 

J.S. Day, H.G.M. Edwards, S.A. Dobrowski and A.M. Voice, The detection of drugs of abuse in fingerprints using Raman spectroscopy I latent fingerprints, Spectrochim. Acta Part A Mol. Biomol. Spectros., 60 (2004) 563-568. 

Latent fingerprints on paper have been revealed by combining the amino acids present with reagents such as ninhydrin (see 37), dansyl chloride (92), fluorescamine (154), 4-chloro-7-nitrobenzofurazan (127a) and o-phthalaldehyde (see reaction 7). To avoid some problems encountered with these reagents it was proposed to use 1,8-diazafluorenone (155), leading to the formation of highly fluorescent ylides (156)349. 

E. R. Menzel, Detection of Latent Fingerprints by Laser-Excited Luminescence, Anal. Chem. 1989,61, 557A. 

If different diacetylenes are cocrystallized they may form reactive or unreactive phases. Which of these actually occur, can depend on the substrate on which crystallization proceeds. For instance, spraying a mixture of a phenylurethane and a p-chlorophenylurethane diacetylene into an oil-covered surface causes formation of the unreactive modification. This effect has been utilized by Miller and Patel to record latent fingerprints. 

DNA evidence has proven to be very valuable, accurate, and reliable, but it is not always available. Fingerprints, however, are easy to see and are sought at every crime scene. To show how latent fingerprints might be made visual, put on your safety glasses and try the following demonstration. 

Cyanoacrylates are also used by forensic scientists to collect fingerprints at crime scenes. The object to be tested is suspended inside a container with at least one transparent side. A few drops of Super Glue or similar cyanoacrylate product is added to the container and the container is sealed and heated to about ioo°C (2i2°F). That heat causes vaporization and polymerization of the cyanoacrylate, resulting in the formation of distinctive white print patterns, a process that make take two hours or more. This cyanoacrylate fuming test has now become the procedure of choice for the detection of latent prints deposited on non-porous objects, such as glass, plastic, rubber, and leather. 

The use of NIR spectra on sediment samples to predict certain constituents from calibration models is, by itself, one important development taking advantage of the speed and low cost of the method. This approach, though, only utilises a small proportion of the information on the organic chemical composition contained in the MR spectra. One alternative, then, is to use the whole NIR spectra as a fingerprint , which can be used to evaluate the variation in sediment composition both in time and space. The total variation represented by several hundred absorbance values can normally be compressed to less then 10 latent variables , components, by different multivariate statistical methods. Similar approaches are used in the process industry where hundred or thousand of signals, used to monitor the performance of some production process, are compressed to a finger print and followed over time. 

From Knowles AM (1978) Aspects of physicochemical methods for the detection of latent fingerprints. Journal of Physics E Scientific Instruments 11 713-721. 

Many substances and formulations have been investigated as fingerprint powders (e.g., carbon black, graphite, metal oxides, sulfates, and carbonates), but the most sensitive powder for general use is considered to be aluminum flake. Aluminum flake powder, because of the flat plate-like structure of each particle and a surface layer of stearic acid, adheres particularly well to a latent fingerprint deposit. In addition, its hardness and reflectivity aid in the photography and transfer of developed prints. 

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