Asne Klein

A field diagnostic test for the improvised explosive urea nitrate

A sensitive, specific and simple color test for the improvised explosive urea nitrate is described. It is based on the formation of a red pigment upon the reaction between urea nitrate and p-dimethylaminocinnamaldehyde (p-DMAC) under neutral conditions. Urea itself, which is the starting material for urea nitrate, does not react with p-DMAC under the same conditions. Other potential sources of false positive response e.g., common fertilizers, medications containing the urea moiety and various amines, do not produce the red pigment with p-DMAC. Exhibits collected from 10 terrorist cases have been tested with p-DMAC. The results were in full agreement with those obtained by instrumental techniques including GC/MS, XRD and IR.

Dual Fingerprint Reagents with Enhanced Sensitivity: 5‐Methoxy‐ and 5‐Methylthioninhydrin

Abstract:  “Dual fingerprint reagents” are chemical formulations which produce with latent fingerprints in a single step, impressions that are both colored and fluorescent. Pre‐mixed solutions of the two commercially available ninhydrin analogues, 5‐methoxyninhydrin (MN) and 5‐methylthioninhydrin (MTN) with zinc or cadmium salts, are true dual reagents. They are much more sensitive than the parent dual reagent, ninhydrin/ZnCl2. The main advantage of the new formulations is that they can be used at room temperature, with no need to cool the sample to liquid nitrogen temperature. At 0.05% concentration, which is 10‐fold lower than the common ninhydrin working solution, MTN/ZnCl2 is as sensitive as DFO in the fluorescence mode and considerably more sensitive in the color mode. MTN is also slightly cheaper than DFO.

Transmission and Reflectance Microspectrophotometry of Inks

Various inks were shown to obey the Beer-Lambert Law as deposits on glass slides. However, spectra of ink traces on paper are subject to scattering and bronzing interferences which cause deviations from the law. Theoretical considerations and experimental results show that there is an inherent advantage of the transmission method over the reflectance method since the former does not suffer from bronzing interference. The deviations from the law may be considerably lower using transmission microspectrophotometry of single inked fibers in a mounting medium instead of the nondestructive transmission method because of large variations in the opacity of paper substrates. In any case, when measuring spectra of ink traces on paper, care must be taken when applying the Beer-Lambert Law to normalize spectra to eliminate concentration differences and substrate background contributions.

Presence of hepatitis C Virus DNA sequences in the DNA of infected patients

Background  Hepatitis C virus (HCV) consists of a single positive RNA molecule. In the present study we investigated the possibility that HCV may undergo integration into the genomic DNA of infected cells.

The Effects of Water-Soaking on Firing Distance Estimations

The effects of water-soaking on firing distance estimations, employing quantitative determinations of gunpowder and metals around the bullets entrance hole, were studied. The main finding was that, since the precision of the quantitative determination is poor, the existing statistical spread cancels out a potential effect of the target soaking. None the less, the prevailing factor is the firing distance, where increments of about 25 cm are clearly distinguishable, in both dry and water-soaked targets.

Bis(benzyltrimethylammonium) bis[(4SR,12SR,18RS,26RS)-4,18,26-trihydroxy-12-oxido-13,17-dioxaheptacyclo[14.10.0.03,14.04,12.06,11.018,26.019,24]hexacosa-1,3(14),6,8,10,15,19,21,23-nonaene-5,25-dione] sesquihydrate: dimeric structure formationvia[O—H—O]−negative charge-assisted hydrogen bonds (–CAHB)with benzyltrimethylammonium counter-ions

The title compound forms a supramolecular dimeric entity via [O—H—O]− negative charge-assisted hydrogen bonds (–CAHB) following a reaction with benzyltrimethylammonium fluoride salt.

Estimation of a Bullet's Diameter Using the Bullet Hole Identification Kit (BTK)

Evaluation of the diameter of a bullet which caused an entrance hole by measuring the diameter of the color rings developed through use of the bullet hole identification kit (BTK) is presented. A direct estimation of the diameter of the bullet can be made, or a range of diameters can be determined. This range depends on the material of the target, and to an extent, on the kind of support behind the target. In the case of woven cotton textiles, this range was found to be small, and larger in other textile materials. Even in these latter cases, one can discriminate between the large and small diameters (for example, those of the 0.22 and 0.38 calibers). These results can be very useful when targets are dark colored or soiled to a degree where the black ring (“ring of dirt”) around the entrance hole is unrecognizable.

Crystal structure of (acetato-κO)(ethanol-κO)[(9S,17S,21S,29S)-9,17,21,29-tetra­hydroxy-18,30-dioxa­octa­cyclo­[18.10.0.02,7.08,19.09,17.011,16.021,29.023,28]triaconta-1,3,5,7,11(16),12,14,19,23(28),24,26-undeca­ene-10,22-dione-κ3O18,O21,O22]caesium ethanol monosolvate

The title compound, C28H16O8·Cs+CH3O−·2CH3CH2OH, was formed in the supramolecular reaction between a vasarene analogue and caesium fluoride, where the F− ion has been replaced by acetate.

The Identification of Stolen Paintings Using Comparison of Various Marks

Several oil paintings, suspected of being stolen, were found in the possession of an art dealer in Tel-Aviv, Israel. The authors were asked to determine if these paintings were the stolen ones, based on photographs, stretchers, and frames submitted by the alleged owners in France. A physical match was found between two of the questioned paintings and two stretchers. Another painting was identified as being previously affixed to the original frame by several nails. The fourth painting was identified as being the one photographed by the alleged owner. This identification was done by comparing micro-topography marks revealed by the illumination conditions of that photograph and of the questioned painting.

Unusual contact marks: connecting the hubcap to the wheel of the car.

A case of homicide and attempted homicide is described. The comparison of tire-marks linked the suspects vehicle to the scene of crime only with low certainty. However, the comparison of the pressure mark on the hubcap found at the scene, with the balance weight on one of the wheels of the suspects car, connected the suspect to the scene of crime with high certainty.