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https://www.readbyqxmd.com/read/28723138/hand-held-femtogram-detection-of-hazardous-picric-acid-with-hydrophobic-ag-nanopillar-sers-substrates-and-mechanism-of-elasto-capillarity
#1
Aron Hakonen, FengChao Wang, Per Ola Andersson, Håkan Wingfors, Tomas Rindzevicius, Michael Stenbæk Schmidt, Venugopal Rao Soma, Shicai Xu, YingQi Li, Anja Boisen, HengAn Wu
Picric acid (PA) is a severe environmental and security risk due to its unstable, toxic, and explosive properties. It is also challenging to detect in trace amounts and in situ because of its highly acidic and anionic character. Here, we assess sensing of PA under nonlaboratory conditions using surface-enhanced Raman scattering (SERS) silver nanopillar substrates and hand-held Raman spectroscopy equipment. The advancing elasto-capillarity effects are explained by molecular dynamics simulations. We obtain a SERS PA detection limit on the order of 20 ppt, corresponding attomole amounts, which together with the simple analysis methodology demonstrates that the presented approach is highly competitive for ultrasensitive analysis in the field...
February 24, 2017: ACS Sensors
https://www.readbyqxmd.com/read/28688450/alignment-orientation-and-coulomb-explosion-of-difluoroiodobenzene-studied-with-the-pixel-imaging-mass-spectrometry-pimms-camera
#2
Kasra Amini, Rebecca Boll, Alexandra Lauer, Michael Burt, Jason W L Lee, Lauge Christensen, Felix Brauβe, Terence Mullins, Evgeny Savelyev, Utuq Ablikim, Nora Berrah, Cédric Bomme, Stefan Düsterer, Benjamin Erk, Hauke Höppner, Per Johnsson, Thomas Kierspel, Faruk Krecinic, Jochen Küpper, Maria Müller, Erland Müller, Harald Redlin, Arnaud Rouzée, Nora Schirmel, Jan Thøgersen, Simone Techert, Sven Toleikis, Rolf Treusch, Sebastian Trippel, Anatoli Ulmer, Joss Wiese, Claire Vallance, Artem Rudenko, Henrik Stapelfeldt, Mark Brouard, Daniel Rolles
Laser-induced adiabatic alignment and mixed-field orientation of 2,6-difluoroiodobenzene (C6H3F2I) molecules are probed by Coulomb explosion imaging following either near-infrared strong-field ionization or extreme-ultraviolet multi-photon inner-shell ionization using free-electron laser pulses. The resulting photoelectrons and fragment ions are captured by a double-sided velocity map imaging spectrometer and projected onto two position-sensitive detectors. The ion side of the spectrometer is equipped with a pixel imaging mass spectrometry camera, a time-stamping pixelated detector that can record the hit positions and arrival times of up to four ions per pixel per acquisition cycle...
July 7, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28662404/novel-laser-induced-photoacoustic-spectroscopy-for-instantaneous-trace-detection-of-explosive-materials
#3
Yasser H El-Sharkawy, Sherif Elbasuney
Laser photoacoustic spectroscopy (LPAS) is an attractive technology in terms of simplicity, ruggedness, and overall sensitivity; it detects the time dependent heat generated (thermo-elastic effect) in the target via interaction with pulsed optical radiation. This study reports on novel LPAS technique that offers instant and standoff detection capabilities of trace explosives. Over the current study, light is generated using pulsed Q-switched Nd:YAG laser; the generated photoacoustic response in stimulated explosive material offers signature values that depend on the optical, thermal, and acoustical properties...
June 15, 2017: Forensic Science International
https://www.readbyqxmd.com/read/28648260/broadening-the-perspective-on-gun-violence-an-examination-of-the-firearms-industry-1990-2015
#4
Victoria M Smith, Michael Siegel, Ziming Xuan, Craig S Ross, Sandro Galea, Bindu Kalesan, Eric Fleegler, Kristin A Goss
INTRODUCTION: Firearm violence injures or kills 100,000 Americans each year. This paper applies the Host-Agent-Vector-Environment model to this issue. Research on firearm violence tends to focus on two elements-the host (i.e., victims of firearm violence) and the environment (i.e., gun policies)-but little attention has been paid to the agent (the gun and ammunition) or the vector (firearm manufacturers, dealers, and the industry lobby). METHODS: Using Bureau of Alcohol, Tobacco, Firearms and Explosives data, trends in firearm manufacturing were investigated from 1990 to 2015...
June 17, 2017: American Journal of Preventive Medicine
https://www.readbyqxmd.com/read/28604118/practical-tips-for-working-as-an-expedition-doctor-on-high-altitude-expeditions
#5
Anne Brants, Tracee Metcalfe
Brants, Anne, and Tracee Metcalfe. Practical tips for working as an expedition doctor on high-altitude expeditions. High Alt Med Biol 00:000-000, 2017.-With the explosion of adventure travel over the past decade, there has been a concurrent increase in mountaineering expeditions to extreme elevations, including many of the 8000-m peaks. This trend has created an increased demand for qualified expedition doctors to provide specialized medical advice and care to climbers and expedition staff. This review is intended to help physicians prepare for work on such expeditions...
June 12, 2017: High Altitude Medicine & Biology
https://www.readbyqxmd.com/read/28581557/a-porous-two-dimensional-zn-ii-coordination-polymer-exhibiting-sc-sc-transmetalation-with-cu-ii-efficient-heterogeneous-catalysis-for-the-henry-reaction-and-detection-of-nitro-explosives
#6
Mayank Gupta, Dinesh De, Sanchari Pal, Tapan K Pal, Kapil Tomar
The linker 5-(benzylamino)isophthalic acid (H2L) forms a robust 2D Zn(ii)-coordination polymer, {[Zn8(L)6(μ3-OH)4(H2O)6]·(DMF)·(H2O)2.5}n(1Zn) consisting of [Zn4(μ3-OH)2](6+) SBUs. It further shows strong ππ interactions between the layers to form an overall 3D structure with well-defined channels. Metal bound water molecules are directed towards these channels. Upon heating, these metal bound water molecules are lost along with lattice solvent molecules to afford coordinatively unsaturated metal centers that can be utilized as an efficient heterogeneous catalyst for the C-C bond forming nitroaldol or Henry reaction...
June 13, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28547850/detection-of-contact-traces-of-powdery-substances
#7
Wojciech Pawłowski, Łukasz Matyjasek, Monika Karpińska
The current practice in securing the contact traces of chemical substances taken from clothes belonging to a person suspected of manual handling explosives is focused on pockets and cuffs. The outerwear worn by people who had contact with fluorescent powders that simulate explosives and drugs was the subject of this study. Clothes were first exposed to the test substance for a period of time and then analyzed by fluorescence methods to determine the location of the highest quantity of traces. The results obtained from the study confirm that the areas with the highest concentration of powdery traces are different from those suggested by current forensic practice...
May 26, 2017: Journal of Forensic Sciences
https://www.readbyqxmd.com/read/28469009/heroes-of-the-engram
#8
Sheena A Josselyn, Stefan Köhler, Paul W Frankland
In 1904, Richard Semon introduced the term "engram" to describe the neural substrate responsible for (or at least important in) storing and recalling memories (i.e., a memory trace). The recent introduction of a vast array of powerful new tools to probe and manipulate memory function at the cell and neuronal circuit level has spurred an explosion of interest in studying the engram. However, the present "engram renaissance" was not borne in isolation but rather builds on a long tradition of memory research. We believe it is important to acknowledge the debts our current generation of scientists owes to those scientists who have offered key ideas, persevered through failed experiments and made important discoveries before us...
May 3, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28451678/a-novel-luminescent-pb-ii-organic-framework-exhibiting-a-rapid-and-selective-detection-of-trace-amounts-of-nacs-and-fe-3-with-excellent-recyclability
#9
Xuan Luo, Xiao Zhang, Yuanling Duan, Xiaolin Wang, Jiaming Zhao
A novel three-dimensional metal organic framework, Pb3O2L (1) (H2L = 4-(1H-tetrazol-5-yl)phenol), with a unique 3D network structure exhibits excellent luminescence and good stability in water and other organic solvents. 1 can act as a promising dual functional sensor for the detection and recognition of nitroaromatic explosives (NACs) and Fe(3+) ions via fluorescence quenching with high selectivity and sensitivity in an aqueous phase. Importantly, 1 as a fluorescent sensor of Fe(3+) can be simply and quickly regenerated, which represents a rare example of a reported luminescent sensor of Fe(3+) ions...
May 16, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28448003/standardized-method-for-measuring-collection-efficiency-from-wipe-sampling-of-trace-explosives
#10
Jennifer R Verkouteren, Jeffrey A Lawrence, Matthew E Staymates, Edward Sisco
One of the limiting steps to detecting traces of explosives at screening venues is effective collection of the sample. Wipe-sampling is the most common procedure for collecting traces of explosives, and standardized measurements of collection efficiency are needed to evaluate and optimize sampling protocols. The approach described here is designed to provide this measurement infrastructure, and controls most of the factors known to be relevant to wipe-sampling. Three critical factors (the applied force, travel distance, and travel speed) are controlled using an automated device...
April 10, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28425532/emerging-tellurium-nanostructures-controllable-synthesis-and-their-applications
#11
REVIEW
Zhen He, Yuan Yang, Jian-Wei Liu, Shu-Hong Yu
Tellurium (Te) is a rare element in trace amounts of about one part per billion, comparable to that of platinum and ranked 75th in the abundance of the elements in the earth crust. Te nanostructures, as narrow bandgap semiconductors, have numerous potential applications in the fabrication of many modern devices. The past decades have witnessed an explosion in new strategies for synthesizing diverse emerging Te nanostructures with controlled compositions, sizes, shapes, and structures. Their structure-determined nature makes functional Te nanomaterials an attractive candidate for modern applications...
April 20, 2017: Chemical Society Reviews
https://www.readbyqxmd.com/read/28409445/ion-mobility-spectrometry-high-resolution-ltq-orbitrap-mass-spectrometry-for-analysis-of-homemade-explosives
#12
Nathan Hagan, Ilana Goldberg, Adam Graichen, Amanda St Jean, Ching Wu, David Lawrence, Plamen Demirev
The detailed chemical characterization of homemade explosives (HMEs) and other chemicals that can mimic or mask the presence of explosives is important for understanding and improving the performance of commercial instrumentation used for explosive detection. To that end, an atmospheric-pressure drift tube ion mobility spectrometry (IMS) instrument has been successfully coupled to a commercial tandem mass spectrometry (MS) system. The tandem MS system is comprised of a linear ion trap and a high resolution Orbitrap analyzer...
August 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/28381055/eye-safe-near-infrared-trace-explosives-detection-and-imaging
#13
Gennady Rasskazov, Anton Ryabtsev, Marcos Dantus
We report the development of a non-contact no-reagents system operating in the eye-safe 1560-1800 nm wavelength range for standoff trace detection of explosives and high-speed imaging. Experimental results are provided for a number of chemicals including explosives on a variety of surfaces at sub-microgram per cm<sup>2</sup> concentration. Chemically specific images were collected at 0.06 ms per pixel. Results from this effort indicate that the combination of modern industrial fiber lasers and nonlinear optical spectroscopy can address next generation eye-safe trace detection of chemicals including explosives...
March 20, 2017: Optics Express
https://www.readbyqxmd.com/read/28372430/trace-explosives-sensor-testbed-testbed
#14
Greg E Collins, Michael P Malito, Cy R Tamanaha, Mark H Hammond, Braden C Giordano, Adam L Lubrano, Christopher R Field, Duane A Rogers, Russell A Jeffries, Richard J Colton, Susan L Rose-Pehrsson
A novel vapor delivery testbed, referred to as the Trace Explosives Sensor Testbed, or TESTbed, is demonstrated that is amenable to both high- and low-volatility explosives vapors including nitromethane, nitroglycerine, ethylene glycol dinitrate, triacetone triperoxide, 2,4,6-trinitrotoluene, pentaerythritol tetranitrate, and hexahydro-1,3,5-trinitro-1,3,5-triazine. The TESTbed incorporates a six-port dual-line manifold system allowing for rapid actuation between a dedicated clean air source and a trace explosives vapor source...
March 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28349688/portable-and-reliable-surface-enhanced-raman-scattering-silicon-chip-for-signal-on-detection-of-trace-trinitrotoluene-explosive-in-real-systems
#15
Na Chen, Pan Ding, Yu Shi, Tengyu Jin, Yuanyuan Su, Houyu Wang, Yao He
There is an increasing interest in the development of surface-enhanced Raman scattering (SERS) sensors for rapid and accurate on-site detection of hidden explosives. However, portable SERS methods for trace explosive detection in real systems remain scarce, mainly due to their relatively poor reliability and portability. Herein, we present the first demonstration of a portable silicon-based SERS analytical platform for signal-on detection of trace trinitrotoluene (TNT) explosives, which is made of silver nanoparticle (AgNP)-decorated silicon wafer chip (0...
April 10, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28340788/rapid-identification-and-desorption-mechanisms-of-nitrogen-based-explosives-by-ambient-micro-fabricated-glow-discharge-plasma-desorption-ionization-mfgdp-mass-spectrometry
#16
CaiYan Tian, JinWei Yin, ZhongJun Zhao, Yinchenxi Zhang, YiXiang Duan
A novel technique of micro-fabricated glow discharge plasma desorption/ionization mass spectrometry was investigated for the first time in negative ion mode in this study. Negative ion micro-fabricated glow discharge plasma desorption/ionization mass spectrometry (NI-MFGDP-MS) was successfully applied to identify trace explosives in open air. Six explosives and explosives-related compounds were directly analyzed in seconds with this ion source. The ions of [M-H](-) were predominant for 2-methyl-1,3,5-trinitrobenzene (trinitrotoluene, TNT) and 2,4,6-trinitrophenol (picric acid), and [M+NO3](-) were dominant ions for 1,3,5-trinitro-perhydro-1,3,5-triazine (cyclonite, RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (octogen, HMX), 1,2,3-trinitroxypropane (nitroglycerin, NG), and pentaerythritol tetranitrate (PETN)...
May 15, 2017: Talanta
https://www.readbyqxmd.com/read/28324768/analysis-of-different-materials-subjected-to-open-air-explosions-in-search-of-explosive-traces-by-raman-microscopy
#17
Félix Zapata, Carmen García-Ruiz
Post-explosion scenes offer such chaos and destruction that evidence recovery and detection of post-blast residues from the explosive in the surrounding materials is highly challenging and difficult. The suitability of materials to retain explosives residues and their subsequent analysis has been scarcely investigated. Particularly, the use of explosive mixtures containing inorganic oxidizing salts to make improvised explosive devices (IEDs) is a current security concern due to their wide availability and lax control...
March 16, 2017: Forensic Science International
https://www.readbyqxmd.com/read/28319855/microbial-bioreporters-of-trace-explosives
#18
REVIEW
Benjamin Shemer, Ori Koshet, Sharon Yagur-Kroll, Shimshon Belkin
Since its introduction as an explosive in the late 19th century, 2,4,6-trinitrotoluene (TNT), along with other explosive compounds, has left numerous environmental marks. One of these is widespread soil and water pollution by trace explosives in military proving grounds, manufacturing facilities, or actual battlefields. Another dramatic impact is that exerted by the millions of landmines and other explosive devices buried in large parts of the world, causing extensive loss of life, injuries, and economical damage...
March 17, 2017: Current Opinion in Biotechnology
https://www.readbyqxmd.com/read/28292727/analysis-of-dna-from-post-blast-pipe-bomb-fragments-for-identification-and-determination-of-ancestry
#19
Esiri Tasker, Bobby LaRue, Charity Beherec, David Gangitano, Sheree Hughes-Stamm
Improvised explosive devices (IEDs) such as pipe bombs are weapons used to detrimentally affect people and communities. A readily accessible brand of exploding targets called Tannerite® has been identified as a potential material for abuse as an explosive in pipe bombs. The ability to recover and genotype DNA from such weapons may be vital in the effort to identify suspects associated with these devices. While it is possible to recover DNA from post-blast fragments using short tandem repeat markers (STRs), genotyping success can be negatively affected by low quantities of DNA, degradation, and/or PCR inhibitors...
May 2017: Forensic Science International. Genetics
https://www.readbyqxmd.com/read/28284543/aquatic-environmental-changes-and-anthropogenic-activities-reflected-by-the-sedimentary-records-of-the-shima-river-southern-china
#20
Lei Gao, Zhuowei Wang, Jiju Shan, Jianyao Chen, Changyuan Tang, Ming Yi
Reconstructing historical sedimentary records is essential for better understanding the effects of anthropogenic activities on river environments. We used lead-210 to date riverine sediment core from the Shima River in China. We obtained a sedimentary history of 34 years (1982-2015) for core S2, which had a length of 34 cm. The sedimentation rate of 0.304-2.04 cm y(-1) was controlled by both flood events and anthropogenic activities. The conservative element content depth profiles remained relatively constant, suggestive of a relatively stable sediment provenance; therefore, the increase in the sedimentation rate over time was mainly the result of domestic and industrial wastewater effluent and the construction of a rubber dam at the middle and lower reach of the Shima River...
May 2017: Environmental Pollution
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