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Trace explosives

Heidi Lees, Félix Zapata, Merike Vaher, Carmen García-Ruiz
This novel investigation focused on studying the transfer of explosive residues (TNT, HMTD, PETN, ANFO, dynamite, black powder, NH4 NO3 , KNO3 , NaClO3 ) in ten consecutive fingerprints to two different surfaces - cotton fabric and polycarbonate plastic - by using multispectral imaging (MSI). Imaging was performed employing a reflex camera in a purpose-built photo studio. Images were processed in MATLAB to select the most discriminating frame - the one that provided the sharpest contrast between the explosive and the material in the red-green-blue (RGB) visible region...
July 1, 2018: Talanta
Tessa Collins, Rachael Greenberg, Michael Siegel, Ziming Xuan, Emily F Rothman, Shea W Cronin, David Hemenway
In a cross-sectional, panel study, we examined the relationship between state firearm laws and the extent of interstate transfer of guns, as measured by the percentage of crime guns recovered in a state and traced to an in-state source (as opposed to guns recovered in a state and traced to an out-of-state source). We used 2006-2016 data on state firearm laws obtained from a search of selected state statutes and 2006-2016 crime gun trace data from the Bureau of Alcohol, Tobacco, Firearms, and Explosives. We examined the relationship between state firearm laws and interstate transfer of guns using annual data from all 50 states during the period 2006-2016 and employing a two-way fixed effects model...
April 18, 2018: Journal of Urban Health: Bulletin of the New York Academy of Medicine
Thomas P Forbes, Edward Sisco
Ambient mass spectrometry has evolved rapidly over the past decade, yielding a plethora of platforms and demonstrating scientific advancements across a range of fields from biological imaging to rapid quality control. These techniques have enabled real-time detection of target analytes in an open environment with no sample preparation and can be coupled to any mass analyzer with an atmospheric pressure interface; capabilities of clear interest to the defense, customs and border control, transportation security, and forensic science communities...
April 17, 2018: Analyst
Ramón González-Méndez, Peter Watts, D Fraser Reich, Stephen J Mullock, Stuart Cairns, Peter Hickey, Matthew Brookes, Chris Anthony Mayhew
The high sensitivity of Proton Transfer Reaction-Mass Spectrometry (PTR-MS) makes it a suitable analytical tool for detecting trace compounds. Its specificity is primarily determined by the accuracy of identifying the m/z of the product ions specific to a particular compound. However, specificity can be enhanced by changing the product ions (concentrations and types) through modifying the reduced electric field. For current PTR-MS systems this is not possible for trace compounds that would only be present in the reaction chamber of a PTR-MS for a short time (seconds)...
April 9, 2018: Analytical Chemistry
Sukrit Ranjan, Zoe R Todd, John D Sutherland, Dimitar D Sasselov
A key challenge in origin-of-life studies is understanding the environmental conditions on early Earth under which abiogenesis occurred. While some constraints do exist (e.g., zircon evidence for surface liquid water), relatively few constraints exist on the abundances of trace chemical species, which are relevant to assessing the plausibility and guiding the development of postulated prebiotic chemical pathways which depend on these species. In this work, we combine literature photochemistry models with simple equilibrium chemistry calculations to place constraints on the plausible range of concentrations of sulfidic anions (HS- , HSO3 - , SO3 2- ) available in surficial aquatic reservoirs on early Earth due to outgassing of SO2 and H2 S and their dissolution into small shallow surface water reservoirs like lakes...
April 8, 2018: Astrobiology
Debamalya Ghosh, Uma Dutta, Ariful Haque, Natalia E Mordvinova, Oleg I Lebedev, Kamalesh Pal, Arup Gayen, Md Motin Seikh, Partha Mahata
Here, we report the luminescence based sensing of trace amounts of nitroaromatic explosive organic compounds. The luminescence emission of nanosized spinel oxide ZnCr2O4 with high chemical and thermal stabilities has been used as a potential probe to detect such organic explosives. Low temperature solution combustion synthesized ZnCr2O4 oxide with an average particle size of ∼9 nm exhibits strong luminescence emission at 410 nm upon excitation at 260 nm in an aqueous suspension. The presence of nitroaromatics in ZnCr2O4 suspension dramatically suppresses the luminescence emission providing an opportunity to detect it quantitatively...
March 21, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Luis A Buatois, John Almond, M Gabriela Mángano, Sören Jensen, Gerard J B Germs
Trace fossils of sediment bulldozers are documented from terminal Ediacaran strata of the Nama Group in Namibia, where they occur in the Spitskop Member of the Urusis Formation (Schwarzrand Subgroup). They consist of unilobate to bilobate horizontal to subhorizontal trace fossils describing scribbles, circles and, more rarely, open spirals and meanders, and displaying an internal structure indicative of active fill. Their presence suggests that exploitation of the shallow infaunal ecospace by relatively large bilaterians was already well underway at the dawn of the Phanerozoic...
March 14, 2018: Scientific Reports
Xinyuan Zhou, Liping Yang, Yuzhi Bian, Xiang Ma, Ning Han, Yunfa Chen
Nowadays, the detection of low concentration combustible methane gas has attracted great concern. In this paper, a coupling p+n field effect transistor (FET) amplification circuit is designed to detect methane gas. By optimizing the load resistance ( RL ), the response to methane of the commercial MP-4 sensor can be magnified ~15 times using this coupling circuit. At the same time, it decreases the limit of detection (LOD) from several hundred ppm to ~10 ppm methane, with the apparent response of 7.0 ± 0.2 and voltage signal of 1...
March 6, 2018: Sensors
Richard S Saver
The Physician Payments Sunshine Act ("Sunshine Act"), enacted to address financial conflicts in health care, is the first comprehensive federal legislation mandating public reporting of payments between drug companies, device manufacturers, and medicine. This article analyzes the Sunshine Act's uneven record, exploring how the law serves as an intriguing example of the uncertain case for transparency regulation in health care. The Sunshine Act's bumpy rollout demonstrates that commanding transparency through legislation can be arduous because of considerable implementation challenges...
November 2017: American Journal of Law & Medicine
Thakshila Liyanage, Ashur Rael, Sidney Shaffer, Shozaf Zaidi, John V Goodpaster, Rajesh Sardar
Apart from high sensitivity and selectivity of surface-enhanced Raman scattering (SERS)-based trace explosive detection, efficient sampling of explosive residue from real world surfaces is very important for homeland security applications. Herein, we demonstrate an entirely new SERS nanosensor fabrication approach. The SERS nanosensor was prepared by self-assembling chemically synthesized gold triangular nanoprisms (Au TNPs), which we show display strong electromagnetic field enhancements at the sharp tips and edges, onto a pressure-sensitive flexible adhesive film...
February 12, 2018: Analyst
Jennifer L Thomas, Christopher C Donnelly, Erin W Lloyd, Robert F Mothershead, Mark L Miller
An improved cleanup method has been developed for the recovery of trace levels of 12 nitro-organic explosives in soil, which is important not only for the forensic community, but also has environmental implications. A wide variety of explosives or explosive-related compounds were evaluated, including nitramines, nitrate esters, nitroaromatics, and a nitroalkane. Fortified soil samples were extracted with acetone, processed via solid phase extraction (SPE), and then analyzed by gas chromatography with electron capture detection...
March 2018: Forensic Science International
Hamza Turhan, Ece Tukenmez, Bunyamin Karagoz, Niyazi Bicak
Crosslinked 2-bromoethyl methacrylate polymer (PBEMA) was prepared in micro-spherical form (2-5µm) by precipitation polymerization methodology. The bromide substituent was substituted with an azide group, which was then coupled with 1-[(2-Propynyloxy)methyl]pyrene] via alkyne-azide click chemistry. The pyrene-linked microspheres showed an intense green-blue excimer emission with a maximum at 480nm, implying π-π stacking between the pyrene moieties on the microsphere surfaces. This fluorescence emission is extremely sensitive to the aromatic nitro compounds...
March 1, 2018: Talanta
Benjamin Shemer, Sharon Yagur-Kroll, Carina Hazan, Shimshon Belkin
DNT (2,4-dinitrotoluene), a volatile impurity in military-grade 2,4,6-trinitrotoluene (TNT)-based explosives, is a potential tracer for the detection of buried landmines and other explosive devices. We have previously described an Escherichia coli bioreporter strain engineered to detect traces of DNT and have demonstrated that the yqjF gene promoter, the sensing element of this bioreporter, is induced not by DNT but by at least one of its transformation products. In the present study, we have characterized the initial stages of DNT biotransformation in E...
February 15, 2018: Applied and Environmental Microbiology
Yi Li, Rui Lu, Jinyou Shen, Weiqing Han, Xiuyun Sun, Jiansheng Li, Lianjun Wang
A flexible 3D hybrid PC/Ag surface-enhanced Raman scattering (SERS) substrate was fabricated through the combination of electrospinning and in situ chemical reduction. Due to the rough surface morphology and the intricate 3D structure, a high density of Raman "hotspots" was formed at the junctions of cross-linked nanofibers, resulting in excellent sensitivity to a probe molecule (4-aminothiophenol). The nanofibers were modified with l-cysteine to capture TNT molecules by the formation of a Meisenheimer complex, after which positively charged 4-ATP-labelled AgNPs were introduced to the system, which both generated more hotspots and led to a linear relationship between the TNT concentration and the SERS intensity of the labelled molecules...
December 4, 2017: Analyst
Jian Ma, Zhongfu Shen, Yong-Chun Yu, Song-Hai Shi
Delineating the lineage of neural cells that captures the progressive steps in their specification is fundamental to understanding brain development, organization, and function. Since the earliest days of embryology, lineage questions have been addressed with methods of increasing specificity, capacity, and resolution. Yet, a full realization of individual cell lineages remains challenging for complex systems. A recent explosion of technical advances in genome-editing and single-cell sequencing has enabled lineage analysis in an unprecedented scale, speed, and depth across different species...
November 7, 2017: Current Opinion in Neurobiology
Chao Zhang, Jochem Bijlard, Christine Staiger, Serena Scollen, David van Enckevort, Youri Hoogstrate, Alexander Senf, Saskia Hiltemann, Susanna Repo, Wibo Pipping, Mariska Bierkens, Stefan Payralbe, Bas Stringer, Jaap Heringa, Andrew Stubbs, Luiz Olavo Bonino Da Silva Santos, Jeroen Belien, Ward Weistra, Rita Azevedo, Kees van Bochove, Gerrit Meijer, Jan-Willem Boiten, Jordi Rambla, Remond Fijneman, J Dylan Spalding, Sanne Abeln
The availability of high-throughput molecular profiling techniques has provided more accurate and informative data for regular clinical studies. Nevertheless, complex computational workflows are required to interpret these data. Over the past years, the data volume has been growing explosively, requiring robust human data management to organise and integrate the data efficiently. For this reason, we set up an ELIXIR implementation study, together with the Translational research IT (TraIT) programme, to design a data ecosystem that is able to link raw and interpreted data...
2017: F1000Research
Xingliang Zhang, Wei Liu, Yukio Isozaki, Tomohiko Sato
The trace fossil record implies that large worm-like animals were in place along with the skeletonizing organisms during the initial stage of the Cambrian explosion. Body fossils of large worms, however, have so far not been found. Here, we describe a large, soft-bodied, worm-like organism, Vittatusivermis annularius gen. et sp. nov. from the lowest Cambrian of South China, which is constrained to the Fortunian Age (541-529 Ma) of the Cambrian Period. The elongate body of Vittatusivermis was large enough to have supported organ systems and a fluid skeleton that facilitated peristaltic locomotion, thus allowing for more complex patterns of movement than those of flatworms...
November 6, 2017: Scientific Reports
Wojciech Pawłowski, Łukasz Matyjasek, Katarzyna Cieślak, Monika Karpińska
The philosophy underlying the procedure with the trace from the moment of the securing of the evidence up to its ultimate inspection is of significance for the result achieved. Hands of the people who conduct investigative action or of the experts involved in examinations contaminated with explosives may adversely affect results of the analyses. The contamination effect is one of the most dangerous consequences of non-observance of the strict rules in handling the traces secured on the crime scene. The aim of this research work was to examine whether at all, and if so, with what an ease and at which stage of the analytical procedure there occurs a likely contamination of the evidence material with explosives such as TNT, RDX, PETN, NG...
December 2017: Forensic Science International
Stamatios Giannoukos, Agapios Agapiou, S Taylor
On-site chemical sensing of compounds associated with security and terrorist attacks is of worldwide interest. Other related bio-monitoring topics include identification of individuals posing a threat from illicit drugs, explosive manufacturing, as well as searching for victims of human trafficking and collapsed buildings. The current status of field analytical technologies is directed towards the detection and identification of vapours and volatile organic compounds (VOCs). Some VOCs are associated with exhaled breath; where research is moving from individual breath testing (volatilome) to cell breath (microbiome) and most recently to crowd breath metabolites (exposome)...
October 25, 2017: Journal of Breath Research
Sultan Ben-Jaber, William J Peveler, Raul Quesada-Cabrera, Christian W O Sol, Ioannis Papakonstantinou, Ivan P Parkin
Surface-enhanced Raman spectroscopy (SERS) has been widely utilised as a sensitive analytical technique for the detection of trace levels of organic molecules. The detection of organic compounds in the gas phase is particularly challenging due to the low concentration of adsorbed molecules on the surface of the SERS substrate. This is particularly the case for explosive materials, which typically have very low vapour pressures, limiting the use of SERS for their identification. In this work, silver nanocubes (AgNCs) were developed as a highly sensitive SERS substrate with very low limit-of-detection (LOD) for explosive materials down to the femtomolar (10(-15) M) range...
November 2, 2017: Nanoscale
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