Use of gold nanoparticles as molecular intermediates for the detection of fingermarks

Among the numerous methods dedicated to the detection of latent fingermarks, the MultiMetal Deposition (MMD) offers, as a main advantage, the ability to be applied on a great number of porous and non-porous surfaces, e.g., paper, plastic, glass, latex, and polystyrene, even if wetted. While considered as a powerful and sensitive technique, MMD is often neglected, mainly because of operational limitations (siliconized vessels, restrictive pH domain, numerous immersion baths, ...). In this contribution, we propose a modification of the standard MMD method so that the procedure is simplified with a number of baths reduced to a minimum. To reach this goal, it was necessary to obtain a fully operable solution which could detect fingermarks in a single step. We chose to take advantage of the molecular recognition mechanisms by functionalizing the gold nanoparticles with a molecular host able to bind itself to gold while keeping the ability to trap molecules in solution. Cyclodextrins were chosen as they can be easily chemically modified to offer gold-binding abilities. Moreover, they are widely used as hosts for various molecular guests (dyes, luminescent molecules, ...). This new formulation has been tested on three different surfaces to attest the feasibility of this strategy. Successful results were obtained with detailed fingermarks offering a good contrast to allow their identification without the need to enhance the results (such as with a physical developer). If the new formulation behaves very similarly to the old one, in terms of experimental conditions, it offers the additional advantage to develop fingermarks after immersing them in only one bath. The goal is thus reached.     

Drug intelligence based on MDMA tablets data: 2. Physical characteristics profiling

One of the tasks of the European project entitled “Collaborative Harmonisation of Methods for Profiling of Amphetamine Type Stimulants” (CHAMP) funded by the sixth framework programme of the European Commission was to develop a harmonised methodology for MDMA profiling and the creation of a common database in a drug intelligence perspective. Part I was dedicated to the analysis of organic impurities formed during synthesis in order to investigate traffic tendencies and highlight potential links between samples, whereas this part focuses on physical characteristics of the MDMA tablets. Diameter, thickness, weight and score were demonstrated to be reliable and relevant features in this drug intelligence perspective. Distributions of samples coming from the same post-tabletting batch (post-TB) and samples coming from different post-TB were very well discriminated by using the squared Euclidean or the Manhattan distance on standardised data. Our findings demonstrated the possibility to discriminate between MDMA samples issued from different post-TB and to find out links between samples coming from a same post-TB. Furthermore, the hypothesis that most of the MDMA samples found on the international market come from the same countries was supported.     

Let's stick together: Understanding Africa's secessionist deficit

Over the last 40 years, Africa has experienced relatively fewersecessionist conflicts than most other regions of the world,even though it is otherwise plagued with political violenceand its countries tend to display a higher prevalence of manyof the factors usually associated with separatism. After empiricallyestablishing Africa’s secessionist deficit, this articlereviews the few existing explanations for it before articulatinga theory which singles out the benefits to African regionalelites (and those who depend on them) of weak sovereign states.In Africa as elsewhere, the article argues, regional leaderscan be expected to capitalize on local grievances and promotesecessions if the potential rewards of a separatist state, inthe absence of international recognition, outweigh the potentialrewards associated with control or partial control of institutionsof the sovereign national state. What distinguishes Africanelites is the relatively greater material returns to sovereigntythat they face. Given the continent’s poverty, the undiversifiednature and commodity dependence of its economies, and the relativelack of accountability of state power, Africa offers a significantmaterial premium to internationally recognized sovereignty,tilting the odds for elites in favour of staying within thestate, even if they do not immediately benefit from power atthe centre. The article then tests the argument against actualAfrican cases of secession, showing that they are usually afunction of variations in the relative rewards of sovereignty.In conclusion, it argues that Africa’s weak sovereigntyequilibrium has contributed to its failure to develop.     

Evaluation of the IDS One-Step™ ELISA kits for the detection of illicit drugs in hair

This work presents the validation of a new immunological assay, the One-Step™ enzyme-linked immunosorbent assay (ELISA) tests from International Diagnostic Systems Corp. for the screening of drugs of abuse (cannabis, amphetamines, opiates, and cocaine) in human hair, with subsequent GC–MS confirmation. After decontamination and segmentation into small pieces, 50 mg of hair sample were incubated in 1 ml of methanol during 16 h at 40 °C. A 100 μL aliquot was collected and evaporated to dryness in presence of 100 μL of methanol/hydrochloric acid (99:1, v/v) to avoid amphetamines loss. The dried extract was dissolved in 100 μL of the “sample and standard diluent” solution included in the kit. This solution was submitted to analysis according to the recommended instructions of the manufacturer. During the validation phase, GC–MS confirmations were conducted according to our fully validated and published methods for opiates, cocaine, cannabis, and amphetamines determinations in hair. In a last development step, these procedures were slightly modified to directly confirm ELISA results by GC–MS using the methanolic extract. Ninety-three specimens were simultaneously screened by the ELISA tests (103 for tetrahydrocannabinol (THC)) and confirmed by GC–MS. Twenty were found positive for cannabis (THC: 0.10–6.50 ng/mg), 21 for cocaine (0.50–55.20 ng/mg), 24 for opiates (6-acetylmorphine (6-AM): 0.20–11.60 ng/mg, MOR: 0.20–8.90 ng/mg, codeine (COD): 0.20–5.90 ng/mg), and 13 for amphetamines (AP: 0.20 and 0.27 ng/mg, methamphetamine (MAP): 0.30 and 1.10 ng/mg, methylenedioxymethamphetamine (MDMA): 0.22–17.80 ng/mg). No false negative results were observed according to the Society of Hair Testing's (SoHT) cutoffs (0.5 ng/mg for cocaine, 0.2 ng/mg for opiates and amphetamines, and 0.1 ng/mg for THC). The One-Step™ ELISA kits appear suitable due to their sensitivity and specificity for drug of abuse screening in hair. This technology should find interest in workplace drug testing or driving license regranting, especially when many samples have to be tested with a high rate of negative samples, as ELISA is an easy and high-throughput method.     

‘I Like Your Colour!’ skin bleaching and geographies of race in urban Ghana

This article explores chemical skin bleaching practices in urban Ghana to demonstrate the ways that particular racialized understandings of meaning are deployed in a contemporary postcolonial African society. I argue that the processes of racialization indexed by skin bleaching in Ghana must be contextualized within global racial formations; specifically, they can only be understood by examining the interlinked local and global ideologies and practices of race. In elaborating this argument, the essay also engages with contemporary African diaspora theorization that tends to foreground diasporic identity and experience at the expense of contemporary continental processes. By bringing a postcolonial African society into a dialogue about race, processes of racialization, and the interlinked transnational construction of black identities, this essay offers one way out of the ambivalent relationship that I believe diaspora theorization has with Africa.     

The Sociology of Law in France: Trends and Paradigms

To suggest that French legal sociology is a field in which a dominant theoretical tendency is identifiable is misleading; equally, attempts to provide insight into the work achieved in French socio-legal studies which presuppose that a complete inventory of the field must be undertaken are misguided. In this article, an exposition of French legal sociology is attempted using different means: following a brief history of the evolution of socio-legal studies in France, the authors suggest different paradigms around which French researchers appear to converge. Eight paradigms are identified, covering the majority of French sociologists and jurists. The article concludes with an analysis of some characteristics of socio-legal studies in general, within the framework of French intellectual and academic life.     

On penal metrics

This paper presents the results of a public survey on the perceived severity of different kinds and levels of penalties gathered using magnitude estimation techniques. Three topics are dealt with. Individual scales of sentence severity are shown to be internally consistent. Then the structural properties of the severity scales of fine, imprisonment, community work, and probation are analyzed. Finally, what a given penalty is worth in relation to other types of punishment from the public's point of view is established and compared to existing exchange rates prescribed in legal statutues or practiced by criminal courts.