Enhanced Characterization of the Smell of Death by Comprehensive Two-Dimensional Gas Chromatography-Time-of-Flight Mass Spectrometry (GCxGC-TOFMS)

Soon after death, the decay process of mammalian soft tissues begins and leads to the release of cadaveric volatile compounds in the surrounding environment. The study of postmortem decomposition products is an emerging field of study in forensic science. However, a better knowledge of the smell of death and its volatile constituents may have many applications in forensic sciences. Domestic pigs are the most widely used human body analogues in forensic experiments, mainly due to ethical restrictions. Indeed, decomposition trials on human corpses are restricted in many countries worldwide. This article reports on the use of comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GCxGC-TOFMS) for thanatochemistry applications. A total of 832 VOCs released by a decaying pig carcass in terrestrial ecosystem, i.e. a forest biotope, were identified by GCxGC-TOFMS. These postmortem compounds belong to many kinds of chemical class, mainly oxygen compounds (alcohols, acids, ketones, aldehydes, esters), sulfur and nitrogen compounds, aromatic compounds such as phenolic molecules and hydrocarbons. The use of GCxGC-TOFMS in study of postmortem volatile compounds instead of conventional GC-MS was successful

β decay of 6He into the α+d continuum

The rare β-decay channel of 6He into the α+d continuum was investigated at the REX-ISOLDE facility. Bunches of postaccelerated 6He ions were implanted into the optical time projection chamber (OTPC), where the decays with emission of charged particles were recorded. This novel technique allowed us to extend the low-energy end of the spectrum down to 150 keV in α+d center of mass, corresponding to a deuteron energy of 100 keV. The branching ratio for this process amounts to [2.78±0.07(stat)±0.17(sys)]×10^{−6}. The shape of the spectrum is found to be in a good agreement with a three-body model, while the total intensity is about 20% larger than the predicted one.We would like to thank the ISOLDE facility for providing the excellent beam. We are grateful to P. Descouvemont for providing us with the results of Ref. [15] in a tabular form. The work was partially supported by the Polish National Science Center under Contract No. UMO-2011/01/B/ST2/01943, by the European Nuclear Science and Applications Research (ENSAR) under Project No. 262010, by the Research Foundation - Flanders (FWO), by GOA/2010/010 (BOF KU Leuven), and by the Interuniversity Attraction Poles Programme initiated by the Belgian Science Policy Office (BriX network P7/12)

The community of Hymenoptera parasitizing necrophagous Diptera in an urban biotope

Most reports published in the field of forensic entomology are focused on Diptera and neglect the Hymenoptera community. However, Hymenoptera are part of the entomofaunal colonisation of a dead body. The use of Hymenoptera parasitoids in forensic entomology can be relevant to evaluate the time of death. Hymenoptera parasitoids of the larvae and pupae of flies may play an important role in the estimation of the post-mortem period, because their time of attack is often restricted to a small, well-defined windows of time in the development of the host insect. However, these parasitoids can interfere with the developmental times of colonising Diptera, and therefore a better understanding of their ecology is needed. The work reported here monitored the presence of adult Hymenoptera parasitoids on decaying pig carcasses in an urban biotope during the summer season (from May to September). Six families and six species were recorded in the field: Aspilota fuscicornis Haliday, Alysia manducator Panzer, Nasonia vitripennis Walker, Tachinaephagus zealandicus Ashmead, Trichopria sp., and Figites sp. In the laboratory, five species emerged from pupae collected in the field: Trichopria sp., Figites sp., A. manducator, N. vitripennis, and T. zealandicus. These five species colonise a broad spectrum of Diptera hosts, including those species associated with decomposing carcasses: Calliphoridae, Muscidae, Fanniidae, and Sarcophagida