Fingerprinting tests

The term fingerprinting refers to chemical analysis tests used to identify the polymer makeup. Although two products will never give identical results, the tests or a combination of tests can be used to relate two equivalent polymers or identify their differences. The goal of chemical fingerprinting is to identify the specific polymer from which the geotextile is made. 

Density and molecular weight tests are commonly performed for geotextiles. Molecular weight determination is described in Section 6.4. Additional types of fingerprinting methods are identified subsequently (Koemer, 2012). 

Thermogravimetric analysis is used to determine polymer additives and ash content, the amount of carbon black, and thermal decomposition. It is particularly useful for geotextiles determining the thermal decomposition time can be employed to predict the in-service life at a given temperature. 

The oxidative induction time is used to determine the quantity and types of antioxidants and to evaluate antioxidant depletion times. 

Differential scanning calorimetry is used to determine the melting point, crystallinity, oxidative induction time, and glass transition. The results of this test can be used to evaluate whether welding two different materials together will be feasible in regards to overlaps in their melting windows. 

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In the human cell there are 23 pairs of chromosomes containing approximately 3000 million base pairs of DNA. Short sequences of DNA, perhaps with as few as 20 nucleotide units and sometimes radiolabeled, can be obtained either by chemical synthesis (gene machine) or from cloning. These short sequences can be used to probe for a complementary sequence by looking for the position to which they bind to any DNA sample under investigation, from blood for example. Such probes can detect as little as 100 fg of DNA and are the basis of forensic genetic fingerprinting tests. 

Used as a fingerprint test for films, coatings and packaging plastics. 

A lab technician sweeps his hair back while he prepares a sample for polymerase chain reaction (PCR). Later, the DNA fingerprinting tests of the sample indicate that the lab technician was at the scene of the crime. What other explanation is there for the results of the DNA test ... 

Fingerprinting can be used to determine whether the material selected in the design phase is in fact the same material being installed onsite. It is a way to assess the overall quality as well as understand the service life of the material. Each project should be evaluated individually and the appropriate fingerprinting tests should be performed. 

Fig. 17 shows NMR line shapes for some of C -Cjg alkanes adsorbed in zeolite ZSM-5. Due to the difference in the intramolecular motion of these alkanes, the line shapes are different. This property can be used as a fingerprint test for identification of adsorbed alkanes in zeolites of similar and different structures. 

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... 

Law enforcement agencies even use cyanoacrylates to obtain fingerprints on irregularly shaped objects and porous surfaces [39]. They first place the objeet to be tested in a tank with warmed ethyl cyanoaerylate. The ECA vapor migrates onto... 

To ensure microbial strains are viable and pure a suite of morphological, biochemical, and cytochemical tests are used to confirm characteristics specific to their taxons. A number of commercially available rapid identification kits are also employed for some common genera. In addition to these taxon specific tests, many of the cultures are tested for their fatty acid methyl ester (FAME) profiles using the commercial MIDI system. The FAME profiles can be compared to the MIDI database for species identification/confirmation purposes. The Biolog system, which yields a metabolic fingerprint of an organism, is another alternative for rapid identification. 

For a commercial database of known metabolic transformations, Borodina et al. [76] extracted all known sites of aromatic hydroxylations. These observed transformations were used to generate all possible transformations for each molecule, giving an estimate of the probability that each transformation would actually occur. The method was 85% accurate in predicting site of aromatic hydroxylation when tested against a second metabolism database containing 1552 molecules. Boyer et al. [77] took a similar approach using reaction center fingerprints to estimate the occurrence ratio of a particular metabolic transformation. The method successfully predicted the three most probable sites of metabolism in 87% of compounds tested. 

Cruciani et al. [92] have developed the program Metasite for the prediction of the site of oxidative metabolism by CYP450 enzymes. Metasite uses GRID molecular interaction fields to fingerprint both structures of CYP450s (from homology models or crystal structures) and test substrates and then matches the fields. Zhou et al. [93] showed that Metasite was able to correctly predict the site(s) of metabolism 78% of the time for 227 CYP3A4 substrates. Caron et al. [94] used Metasite to predict the oxidative metabolism of seven statins. 

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