Raman spectroscopy and laser desorption mass spectrometry for minimal destructive forensic analysis of black and color inkjet printed documents

Inkjet ink analysis is the best way to discriminate between printed documents, or even though more difficult, to connect an inkjet printed document with a brand or model of printers. Raman spectroscopy and laser desorption mass spectrometry (LDMS) have been demonstrated as powerful tools for dyes and pigments analysis, which are ink components. The aim of this work is to evaluate the aforementioned techniques for inkjet inks analysis in terms of discriminating power, information quality, and nondestructive capability. So, we investigated 10 different inkjet ink cartridges (primary colors and black), 7 from the HP manufacturer and one each from Epson, Canon and Lexmark. This paper demonstrates the capabilities of three methods: Raman spectroscopy, LDMS and MALDI-MS. Raman spectroscopy, as it is preferable to try the nondestructive approach first, is successfully adapted to the analysis of color printed documents in most cases. For analysis of color inkjet inks by LDMS, we show that a MALDI matrix (9-aminoacridine, 9AA) is needed to desorb and to ionize dyes from most inkjet inks (except Epson inks). Therefore, a method was developed to apply the 9AA MALDI matrix directly onto the piece of paper while avoiding analyte spreading. The obtained mass spectra are very discriminating and lead to information about ink additives and paper compositions. Discrimination of black inkjet printed documents is more difficult because of the common use of carbon black as the principal pigment. We show for the first time the possibility to discriminate between two black-printed documents coming from different, as well as from the same, manufacturers. Mass spectra recorded from black inks in positive ion mode LDMS detect polyethylene glycol polymers which have characteristic mass distributions and end groups. Moreover, software has been developed for rapid and objective comparison of the low mass range of these positive mode LDMS spectra which have characteristic unknown peaks.     

Using the technology information system on internet

This paper describes the Technology Information System (TIS) available on Internet to help firms locate, navigate, and mine over 100 databases containing information about technology resources and expertise. TIS is managed by the University of Alabama in Huntsville.     

Lethal head injury due to tear-gas cartridge gunshots

We report a fatal head injury caused by a tear-gas cartridge and point out the underestimated potential injury of this type of weapon. Gas pressure wounds and the death mechanisms are also described. A review of the literature and forensic considerations of head injury without projectile are presented.     

A Neo-Downsian Model of the Alternative Vote as a Mechanism for Mitigating Ethnic Conflict in Plural Societies

Among those advocating the use of particular electoralmechanisms to reduce the prospects for conflict and strengthendemocracy in societies that are deeply divided in ethnic orreligious terms, there are two main approaches, one associatedwith Arend Lijphart, one with Donald Horowitz. Lijphartadvocates using electoral rules such as list PR thatstrengthen the power of ethnically or religiously definedpolitical elites in the context of implementing power-sharingmechanisms at the elite level that institutionalize norms suchas proportional allocation and mutual veto across ethnies.Horowitz advocates using a preferential voting method, thealternative vote (AV), within constituencies thatare multi-ethnic in character, to allow for voting acrossethnic lines and to increase the likelihood of electingcandidates whose perceived obligations are wider than theirown ethnic group and/or to foster the creation of coalitionsthat are multi-ethnic in character. The main focus of thisessay is the reformulation of Horowitz’s approach in terms ofideas adapted from the neo-Downsian literature on median votermodels. We illustrate Horowitz’s approach with illustrationsinspired by the predominantly biracial political competitionin Fiji between native Fijians and those of Indian descent.