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.     

Variation in Developmental Time for Geographically Distinct Populations of the Common Green Bottle Fly,Lucilia sericata (Meigen)*

Abstract: Time between death and discovery of remains, or postmortem interval (PMI), can be assessed using blow fly maggot age. Forensic entomologists rely on published, often nonlocal, species‐specific developmental tables to determine maggot age. In a series of common garden experiments, we investigated the developmental rate variation between populations of Lucilia sericata collected from Sacramento, CA, San Diego, CA, and Easton, MA at 16°C, 26°C, and 36°C. For the 16°C trial the time measurement started at egg hatch, while for the higher temperatures the experiment began at oviposition; the wandering stage signified the endpoint for all experiments. The distribution of developmental times differed significantly (ANOVA, p < 0.001) between the three populations within each temperature treatment. We discovered that regional variation of developmental times within a blow fly species exists. This study demonstrates the importance of assembling local population‐specific developmental tables when estimating larval age to determine PMI.     

Improvement in Latent Fingerprint Detection on Thermal Paper Using a One‐Step Ninhydrin Treatment with Polyvinylpyrrolidones (PVP)

Abstract: Most thermosensitive surfaces of thermal paper turn black when they come into contact with polar organic solvents such as are used in ninhydrin petroleum benzin solution. This dark staining reduces the contrast between the developed fingerprint and the background to such an extent that the identification process becomes very difficult. Integrating polyvinylpyrrolidones (PVP) into a ninhydrin solution prevents the black staining, and the developed fingerprints appear in clear contrast to the background. The new ninhydrin solution containing PVP is successful compared to the two‐step ninhydrin–acetone washing method for thermal paper which is popular in Germany.     

Need for standardizing performance evaluation criteria for judicial magistrates in India

This article, after deliberating on utility of performance evaluation (PE) for the judiciary and practices developed in different jurisdictions for PE, examines existing rules on PE of magistrates in India. From these rules, effectiveness and utility of criteria formulated for PE of magistrates by different high courts is mapped to show their shortcomings, and suggestions are provided for improvement. The article relies on the results of a survey among 35 senior district judges to understand how evaluators see their role in the PE. In the end, some suggestions are offered for reforming the existing system of PE – like delinking it from annual confidential reports, establishing independent commission for PE, adopting transparency in PE, widening gap between two evaluations and making PE as a deciding factor for upward career mobility of magistrates.     

Auswirkungen des Emissionshandels auf die Praxis

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Der Eigentumsschutz von Nutzungsmöglichkeiten—ein (un-)gelöstes Problem des Eigentumsgrundrechts?

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