Visualising substrate-fingermark interactions: Solid-state NMR spectroscopy of amino acid reagent development on cellulose substrates

© 2015 Elsevier Ireland Ltd. Most spectroscopic studies of the reaction products formed by ninhydrin, 1,2-indanedione-zinc (Ind-Zn) and 1,8-diazafluoren-9-one (DFO) when reacted with amino acids or latent fingermarks on paper substrates are focused on visible absorption or luminescence spectroscopy. In addition, structural elucidation studies are typically limited to solution-based mass spectrometry or liquid nuclear magnetic resonance (NMR) spectroscopy, which does not provide an accurate representation of the fingermark development process on common paper substrates. The research presented in this article demonstrates that solid-state carbon-13 magic angle spinning NMR (13C-MAS-NMR) is a technique that can not only be utilised for structural studies of fingermark enhancement reagents, but is a promising technique for characterising the effect of paper chemistry on fingermark deposition and enhancement. The latter opens up a research area that has been under-explored to date but has the potential to improve our understanding of how fingermark secretions and enhancement reagents interact with paper substrates

Diverse proviral structure of HIV integrants in clonally expanded cells

n/

Use of Styryl 11 and STaR 11 for the Luminescence Enhancement of Cyanoacrylate-Developed Fingermarks in the Visible and Near-Infrared Regions

Abstract: In current casework, most post-cyanoacrylate stains rely on luminescence emission in the visible region (400-700nm). While traditional stains such as rhodamine 6G work well under most circumstances, some surfaces may generate background luminescence under the same conditions. Detection in the near-infrared region (NIR>700nm) has shown to be effective in minimizing the interferences from such surfaces. The laser dye styryl 11 generated strongly luminescent fingermarks when applied after cyanoacrylate fuming on all surfaces tested. When compared to rhodamine 6G, the dye was superior only when viewed in the NIR. Styryl 11 was subsequently combined with rhodamine 6G, and the mixed stain formulation (named StaR 11 by the authors) induced stronger luminescence compared with styryl 11 alone with an ability to visualize in both the visible and NIR regions. Reliable and consistent results were obtained when using either styryl 11 alone or the STaR 11 mixture. The enhancement achieved did not otherwise vary depending on the source of the fingermark secretions. With visualization possible in both the visible and NIR regions, the styryl 11/rhodamine 6G mixture showed significant potential as a post-cyanoacrylate stain. © 2011 American Academy of Forensic Sciences

Investigation of some of the factors influencing fingermark detection

© 2018 Elsevier B.V. The primary aims of fingermark detection research are to improve the quality and increase the rate of detection of identifiable impressions. This is usually performed through the development of new methods and technologies to provide alternatives to or improve current procedures. While research of this nature is important to pursue, it fails to address the underlying question related to the factors that affect the detection of a latent fingermark. There has been significant research that has examined the differences between techniques, donors and fingermark age, as well as the composition of latent fingermarks. However, they tend not to focus on determining how these factors influence the quality of the developed mark. This study involved the development and evaluation of over 14,000 natural fingermarks deposited on a variety of surfaces to examine the effect of substrate, age, donor variability (both inter- and intra-), depletions and type of finger on fingermark development. Fingermarks were deposited on four substrates (two non-porous and two porous) and developed with either indanedione-zinc (IND-Zn) or cyanoacrylate followed by rhodamine 6G staining (CA + R6G). Three independent assessors graded each mark on the quality of development using an absolute scale proposed by the UK Centre for Applied Science and Technology (CAST). The data generated from these assessments were then analysed for trends or other useful insights. The results from this work reaffirm that individual substrate characteristics (and the choice of development technique) play a significant role in determining the number and quality of marks developed. It was found that fingermarks were more likely to be detected on porous substrates and to also be of a higher quality than on non-porous. The effect of fingermark donor variability was also explored, with significant differences observed between donors and within donors. This research shows that current detection techniques do not detect all available fingermarks, reinforcing the need for further research into the fundamentals of fingermark detection in order to gain a better understanding of the techniques currently used. The study has identified considerations for the development of novel techniques and how we need to account for variability when designing fingermark research experiments

Evaluation of one-step luminescent cyanoacrylate fuming

© 2016 Elsevier Ireland Ltd. One-step luminescent cyanoacrylates have recently been introduced as an alternative to the conventional cyanoacrylate fuming methods. These new techniques do not require the application of a luminescent post-treatment in order to enhance cyanoacrylate-developed fingermarks. In this study, three one-step polymer cyanoacrylates: CN Yellow Crystals (Aneval Inc.), PolyCyano UV (Foster + Freeman Ltd.) and PECA Multiband (BVDA), and one monomer cyanoacrylate: Lumikit™ (Crime Scene Technology), were evaluated against a conventional two-step cyanoacrylate fuming method (Cyanobloom (Foster + Freeman Ltd.) with rhodamine 6G stain). The manufacturers' recommended conditions or conditions compatible with the MVC™ 1000/D (Foster + Freeman Ltd.) were assessed with fingermarks aged for up to 8 weeks on non-porous and semi-porous substrates. Under white light, Cyanobloom generally gave better development than the one-step treatments across the substrates. Similarly when viewed under the respective luminescent conditions, Cyanobloom with rhodamine 6G stain resulted in improved contrast against the one-step treatments except on polystyrene, where PolyCyano UV and PECA Multiband gave better visualisation. Rhodamine 6G post-treatment of one-step samples did not significantly enhance the contrast of any of the one-step treatments against Cyanobloom/rhodamine 6G-treated samples

Metal-Organic Frameworks for fingermark detection — A feasibility study

© 2018 Elsevier B.V. Metal-Organic Frameworks (MOFs) are porous crystalline structures, currently used as sensors, separation membranes, and as catalysts. Due to their physicochemical and optical properties, they have been recently proposed for fingermark detection. This study further explored their potential for fingermark detection. Natural fingermarks, as well as charged and protein-enriched marks, were used to test the efficiency of the technique. Various parameters, such as precursor concentration, pH, immersion time and detection protocols, were investigated and optimised. The performance of the optimised MOF-based method was then compared to that of routinely used techniques. The results obtained indicated that MOFs can effectively detect fingermarks, especially protein-rich marks such as marks contaminated with body fluids. However, after comparison and evaluation against benchmark techniques, results were judged to be inferior to those from currently employed detection methods. However, with further research and optimisation MOFs may be promising as an alternative to current powder suspension techniques

An effective Physical Developer (PD) method for use in Australian laboratories

© 2018, © 2018 Australian Academy of Forensic Sciences. Physical Developer (PD) is an underutilized technique for the development of latent marks on porous surfaces that have been wet, or as a subsequent technique in a development sequence. It is a multistep technique that works by selectively reducing silver ions to silver metal at nucleating sites in fingermark residue. Its use is associated with a plethora of issues, largely surrounding the inherent instability of the working solution. Recently, one of the components of the working solution, Synperonic N, has ceased production, and the recommended replacement is Tween 20. This article addresses factors during PD processing using Tween 20, other than reagent formulations that should be considered when using the technique

Forensic Science: Current State and Perspective by a Group of Early Career Researchers

© 2016, Springer Science+Business Media Dordrecht. Forensic science and its influence on policing and the criminal justice system have increased since the beginning of the twentieth century. While the philosophies of the forensic science pioneers remain the pillar of modern practice, rapid advances in technology and the underpinning sciences have seen an explosion in the number of disciplines and tools. Consequently, the way in which we exploit and interpret the remnant of criminal activity are adapting to this changing environment. In order to best exploit the trace, an interdisciplinary approach to both research and investigation is required. In this paper, nine postdoctoral research fellows from a multidisciplinary team discuss their vision for the future of forensic science at the crime scene, in the laboratory and beyond. This paper does not pretend to be exhaustive of all fields of forensic science, but describes a portion of the postdoctoral fellows’ interests and skills

Technical Aspects for the Evaluation of Circulating Nucleic Acids (CNAs): Circulating Tumor DNA (ctDNA) and Circulating MicroRNAs

Circulating nucleic acids (CNAs), for example, circulating tumor DNA (ctDNA) and circulating microRNA (miRNA), represent promising biomarkers in several diseases including cancer. They can be isolated from many body fluids, such as blood, saliva, and urine. Also ascites, cerebrospinal fluids, and pleural effusion may be considered as a source of CNAs, but with several and intrinsic limitations. Therefore, blood withdrawal represents one of the best sources for CNAs due to the very simple and minimally invasive way of sampling. Moreover, it can be repeated at different time points, giving the opportunity for a real-time monitoring of the disease