Search

2,4,6-Trinitrotoluene (TNT) is a class C carcinogen as rated by the Environmental Protection Agency. One of the toxicity mechanisms of TNT is the covalent binding of its metabolites to critical proteins. However, knowledge about their molecular reaction mechanisms is scarce. Herein, we have provided density functional theory (DFT) simulation evidences for the reaction mechanisms of the nitroso metabolite of TNT with the sulfhydryl group of model thiols for the first time. The results show that the solvent-mediated proton-transfer mechanism plays a significant role in the entire process. For the formation of semimercaptal, the mechanism is slightly different from the previous one where the thiolate anion attacks the nitroso group. The rearrangement of semimercaptal needs to be triggered by an acid or hydrated ion (H3O+), which is consistent with the previous assumption. The other pathway, the conversion of semimercaptal to hydroxylamine, has to overcome a higher barrier, although it does not need the participation of an acid or a hydrated ion. In addition, the details on transition states, intermediates and free energy surfaces for three reactions are given, which make up for the lack of experimental knowledge. These conclusions can help to deeply understand the toxic effects of TNT and other nitroaromatic explosives. [ABSTRACT FROM AUTHOR]

This work aims to investigate the degradation of 2,4,6 trinitrotoluene (TNT) as a model typical nitro‐aromatic compound. The degradation process was carried out by hydroxyl radical that was produced via hydrogen peroxide activated by nano zero‐valent iron (Fe0). The nanoparticles as a source of ferrous ions were synthesized by precipitation method using a starch coating as a stabilizer. The transmission electron microscope analysis revealed that the size of the Fe0 particles is about 40 nm. The operating parameters were optimized using central composite design as a kind of response surface methodology. The degradation efficiency of 91% during 10 minutes and mineralization efficiency of 83% during 40 minutes were obtained under the experimental conditions of 30 mg/L TNT, 104.8 mg/L Fe0, 675 mg/L H2O2, and pH of 3.5. Finally, redwater treatment as real nitro‐aromatic wastewater was evaluated by this process, and 63% removal efficiency was attained after 40 minutes in the optimum condition. © 2018 American Institute of Chemical Engineers Environ Prog, 38: 477–482, 2019 [ABSTRACT FROM AUTHOR]

This paper presents the results of a numerical analysis of the behaviour of a human body after a ground-level explosion. The explosions were generated by condensed charges for different stand-off distances and various masses of explosive. The detonations points were located at distances of 1.0 and 2.0 meters from the dummy (human model) obstacle. The different masses of spherically-shaped TNT charges (0.4–1.0 kg) were initiated centrally. The blast wave propagation was generated using a coupled numerical design, which included Eulerian and Lagrangian descriptions for different domains, i.e. the dummy, air, and explosive domains. The main objective of this work was to present the actual pressures and accelerations around the dummy and the body motion caused by the rapid shock of the pressure action. Reaction forces and moments of anatomical joints were provided. Furthermore, the safety criteria presented in the official standards were compared to the simulation results. In this research, different positions against the loading masses were analysed. In each analysis the same standing human model was used. The dummy geometry was based on a medium size male (1.79 m, 84.8 kg). The human body was modelled as consisting of separate, rigid parts (with adequate masses and inertia moments) connected by joints exhibiting nonlinear behaviour. Anatomical ranges of motion were taken into consideration, and a dedicated numerical technique was proposed to model the resistance moment vs. the range of motion relations for the most important human body joints. [ABSTRACT FROM AUTHOR]

Abstract A new immunoassay format using thermally induced defragmentation of some nitro-explosives with a high degree of selectivity is reported. Specific antibodies against three widely used explosives, 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitroperhydro-1,3,5-triazine (RDX), and pentaerythritol tetranitrate (PETN) were generated by designing suitable haptens using geometry optimization modules. These in-house generated antibodies were used in a newly developed thermal mediated immunochemical biosensing technique which involves the binding of specific antibodies to respective nitro-explosives on a microtiter strip, resulting in the formation of specific immunocomplex. Heating the specific immuno-complex formed on microtiter wells resulted in thermal lysis of nitro-explosives to generate nitrite ions. These ions react with Griess reagent to form a colored chromophore which correlates the concentration of individual explosive in the sample. The present work fulfills the need for an improved explosive detecting system that is highly specific and capable of quickly determining the presence of nitrate containing explosives from a mixture pool. Highlights • A new immunochemical sensing strategy based on thermally induced lysis of nitro-explosives is demonstrated. • Thermolysis of nitro groups from respective explosive-antibodies immunocomplex are monitored by a nitrite specific reagent. • Optically determined color signal correlate the concentration of individual explosive from the pool of sample mixture. • The analytical ability of developed direct immunoassay for PETN, RDX, and TNT detection up to sub-ppm range is demonstrated. • The work fulfil the current need for detecting nitrate containing explosives with high degree of selectivity and accuracy. [ABSTRACT FROM AUTHOR]

This article presents a comparative study on the effectiveness of ventilation to mitigate blasting effects on chambers subjected to confined detonations of high explosives. The pressure time-history that acts on the chamber walls is described by three components: (1) the first shock wave, (2) the train of re-reflected shock waves, and (3) the gas pressure. The radial response of spherical chambers is described by the radial breathing mode and modeled by an equivalent single degree of freedom system. The three pressure components are considered for the calculation of the maximum ductility ratio, which is obtained from the numerical solution of the single degree of freedom chamber response. It is assumed that openings reduce the gas pressure but they have an insignificant effect on shock waves. The dynamic response of fully and partially confined chambers are calculated and compared. Results show that intermediate/small openings (less than 10% of the surface of the chamber) are ineffective to mitigate the chamber response and damage. The vibratory response of the chamber is susceptible to elastic or plastic resonance but it is not considerably modified by the long-term gas pressure because of its high radial breathing mode frequency, allowing concluding that ventilation is ineffective to reduce the maximum response of spherical chambers subjected to internal high explosive explosion. [ABSTRACT FROM AUTHOR]

Abstract Three tree species (Wild olive , Stinkwood and Cape Holy) and a shrub (Dovyalis caffra) were each potted in 20 L pots in order to evaluate the effect of 1,3,5-trinitrotoluene (TNT)-contaminated soil on vegetation. TNT contamination was established by dissolving flake TNT in acetone at 300 and 600 mg per kilogram soil concentrations. One pot for every species was left uncontaminated as control elements. A set of 16 samples, four contaminated, four uncontaminated aerial parts and their corresponding soils, were gathered. These were processed and subjected to a solid phase extraction method to isolate analytes of interest. A laboratory analytical method was applied using ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-qTOF MS). For the UPLC-qTOF MS a gradient for the mobile phase was found which allowed the profiling and separation of metabolites in the aerial parts of the vegetation. This method allowed identification and quantification of major changes caused by TNT contaminated soil on vegetation. The Synapt High Definition Mass Spectrometer SYNAPT HDMS G1 was operated using the electrospray ionisation (ESI) technique in both positive and negative mode. A clear comparison of profiles was achieved and this has been demonstrated by the distinct newly-formed metabolites in the TNT contaminated vegetation understudy. The results have also shown that the chlorophyll region in the contaminated profile was also affected by the uptake of TNT degradation products. This has been observed in the contaminated profiles of Wild olive, Stinkwood and Cape Holly extracts indicating enhanced nutrient availability. Highlights • Analyses of extracts from the aerial parts revealed a diversity of metabolites. • The extracts media was constructed based on the extraction solvent system ratio. • TNT contaminated vegetation revealed new peaks/metabolites not present in controls. • Metabolites of the contaminated aerial parts were identified. • TNT degradation products were absorbed into the aerial parts of the trees. [ABSTRACT FROM AUTHOR]

Abstract Rapid, reliable, onsite approaches for detection trace level of trinitrotoluene (TNT) is a pressing necessity for both homeland security and environmental protection. To this end, hydrophilic amine(-NH 2) protected Au@Ag nanoparticles (NPs) were developed and fabricated as colorimetric paper sensor for delicate detection of TNT. The as-developed nanoprobe selectively reacts with TNT through classic Meisenheimer complex formation by means of charge transfer process from an electron-rich NH 2 group of β-cysteamine to an electron-deficient nitro group on TNT. Due to the absence of this particular interaction of other nitroaromatics, the proposed probe is highly selective for TNT detection with a better linear range (0–20 μg/mL) and limit of detection (LOD) of 0.35 μg/mL. The present work provides a novel and facile strategy to fabricate colorimetric paper sensors with rapid and selective recognition ability for label free analysis of TNT. Graphical Abstract Unlabelled Image Highlights • A colorimetric paper sensor for delicate detection of TNT using Au@Ag NPs was constructed. • A very low detection limit of around 0.35 μg/mL was achieved. • It is a highly rapid and reliable approach which did not require expensive instruments. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Two-phase heterogeneous microfluidic immunosensors investigated. • Capture of gaseous analytes through a thin liquid layer mediated transport. • Interfacial mass transfer, transport (momentum and mass), and reactions studied. • A handy empirical correlation between the capture efficiency and Sh proposed. Abstract In a typical heterogeneous microfluidic immunosensor, the carrier fluid transports the target analytes to the antibodies immobilized on the channel surfaces with a thin liquid layer where they are captured. While single-phase systems (the carrier fluid being a liquid) are well studied, two-phase systems (the carrier fluid being a gas) are less explored. There in particular, the effect of transport parameters on the capture efficiency (a critical performance parameter) has not received much attention, and thus is the subject of study here. Hence, we have investigated the transport and capture of analytes in a two-phase heterogeneous microfluidic immunosensor wherein the target analytes in the gaseous phase are transported to the immobilized antibodies via gas–liquid interfacial mass transfer which strongly depends on flow variables of the gas phase flow. Parametric studies on capture efficiency using the properties of trinitrotoluene (TNT) were used to obtain the effects of important transport parameters on the capture of analyte molecules. The highlight of this work is the development of an empirical correlation between the capture efficiency and the gas-side non-dimensional interfacial mass transfer coefficient (Sherwood number, Sh g). This could help design of a two-phase microfluidic device with improved performance parameters to capture gaseous analytes. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Graphite as a sensor for identification of TNT using 1064 nm wavelength. • The PA study with respect to different weight percentage of graphite in TNT matrix. • Identification of acoustic and optical phonons waves transfer mechanism between GP and TNT using 785 nm wavelength. • Development of a new tool for detection and identification of explosive molecules using commercially available laser systems. Abstract The optical phonon waves transfer mechanism between pure graphite (GP) and trinitrotoluene (TNT) using 1064 nm as an excitation wavelength based on the double resonant Raman effect and the pulsed photoacoustic (PA) technique has been investigated. The study was carried out at a different weight percentage of GP within TNT with respect to the two excitation wavelengths of 532 nm and 1064 nm (30 ps, 10 Hz, Q-switched Nd: YAG laser). The equal and double proportional matrix of the GP and TNT (solid samples) generate a strong PA signal with high quality factor (Q-factor) due to the interaction of optical phonons of GP and TNT in the same phase. The Raman spectra, recorded at 785 nm wavelength provides an insight on the pi-electron coupling between the GP and TNT. The obtained experimental results confirm that the pure GP and its derivatives, which have a SP2/SP3 hybridization, can be used to develop a new sensing optode for the detection and identification of explosive molecules in the visible and near-IR wavelengths range. [ABSTRACT FROM AUTHOR]

A flow‐injection analysis tandem mass spectrometry (FIA MSMS) method was developed for rapid quantitative analysis of 10 different inorganic and organic explosives. Performance is optimized by tailoring the ionization method (APCI/ESI), de‐clustering potentials, and collision energies for each specific analyte. In doing so, a single instrument can be used to detect urea nitrate, potassium chlorate, 2,4,6‐trinitrotoluene, 2,4,6‐trinitrophenylmethylnitramine, triacetone triperoxide, hexamethylene triperoxide diamine, pentaerythritol tetranitrate, 1,3,5‐trinitroperhydro‐1,3,5‐triazine, nitroglycerin, and octohy‐dro‐1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocine with sensitivities all in the picogram per milliliter range. In conclusion, FIA APCI/ESI MSMS is a fast (<1 min/sample), sensitive (~pg/mL LOQ), and precise (intraday RSD < 10%) method for trace explosive detection that can play an important role in criminal and attributional forensics, counterterrorism, and environmental protection areas, and has the potential to augment or replace several of the existing explosive detection methods. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The primitive and defective CL-20/TNT cocrystal models were established. • Molecular dynamics method was applied to predict the properties. • The properties of different models were calculated and compared. • The influences of crystal defects on properties of explosive were evaluated. • The article could provide some novel insights for properties estimation of explosives. Abstract In this work, the "perfect" and adulteration defective crystal models of hexanitrohexaazaisowurtzitane/2,4,6-trinitrotoluene (CL-20/TNT) cocrystal explosive were established. Molecular dynamics simulations were performed to predict the stability, sensitivity, energetic performance and mechanical properties of cocrystal models. The binding energy, trigger bond length distribution, interaction energy of trigger bond, cohesive energy density, detonation parameters and mechanical properties were calculated and compared. The influences of adulteration crystal defect on comprehensive properties of CL-20/TNT cocrystal explosive were explored and estimated. The results show that compared with primitive model, binding energies of defective models are decreased by 0.91–14.67%, i.e., the intermolecular interaction energy is decreased and stability is weakened. The maximum trigger bond length is increased by 0.33–4.36%, while the interaction energy of trigger bond is decreased by 1.33–12.27% and cohesive energy density is decreased by 0.45–11.24%, indicating that sensitivity is increased and safety is decreased. The density, detonation velocity and detonation pressure of defective models are decreased by 0.11–7.75%, 0.13–6.47%, 0.32–16.41%, respectively, illustrating that the power and energy density are decreased. Owing to the influence of crystal defect, tensile modulus is decreased by 0.128–5.683 GPa, bulk modulus is decreased by 0.109–3.409 GPa and shear modulus is decreased by 0.048–2.325 GPa, while Cauchy pressure is increased by 0.031–1.112 GPa, meaning that the rigidity, hardness and rupture strength are decreased, ductility is improved. Therefore, adulteration crystal defect has an undesirable influence on stability, sensitivity and energetic performance of CL-20/TNT cocrystal explosive. [ABSTRACT FROM AUTHOR]

Thermodynamic pathways and reaction initiation mechanisms of shocked TNT (2, 4, 6-trinitrotoluene, formula C6H2(NO2)3CH3) with shock velocities in the range of 6 -10 km⋅s-1 using the first-principles-based ReaxFF reactive force field molecular dynamics and the multiscale shock technique (MSST) are reported in this paper. The decomposition reactions occur at a shock velocity of 7 km⋅s-1 or higher. The shock initiation pressure, 25.1 GPa, is obtained from Rankine−Hugoniot relation. According to the link between macroscopic shock initiation and microscopic chemical reaction events, the formation of TNT-dimer and decomposition to C7H5O5N3 are the dominant initial route for shock induced reaction initiation. At shock speeds equal to or higher than 8km⋅s-1, TNT-dimer is formed and subsequently decomposed to C7H5O5N3, NO2 and NO. The quantity of NO2 molecules reaches maximum when TNT molecules decompose completely. Furthermore, when NO2 molecules are consumed fully, the volume of reaction system begins to expand. TNT molecules are dimerized at each shock condition, and the quantity of dimers is the largest at a shock initiation velocity of 7 km⋅s-1. Finally, the formation and evolution of carbon-containing clusters in shocked TNT are analyzed. [ABSTRACT FROM AUTHOR]

Abstract The main objective of the IAEA verification activities is the timely detection of the switching of a significant quantity of nuclear material (NM). However, from the point of nuclear security the multiple switching of "small" quantities of nuclear material with the aim of their subsequent collection also constitutes one of the main threat to ensuring the exceptionally peaceful use of nuclear materials. In this article this threat assessments were performed under the scenario of diversification of uranium switching. It is shown that diversification of 4%-uranium switching can lead to a substantial increase (up to 30 times) of the risk of uranium disuse even with carrying out proper uranium control and protection. However this effect is observed only when there are large opportunities to search for insiders (the search area is comparable to the existing set of nuclear facilities). The obtained results also prove that a reduction in the level of NM safe management at facilities could allow the collector to complete a chain of unauthorized actions with a significant probability ( P S Q > 0.1). Highlights • Risk-analysis is applied to assessment of the impact of diversification of uranium switching on risk of its non-energy use. • The effect of diversification of 4%-uranium switching on the risk of its unauthorized use may reach 30 times. • Decline of the level of NM safe management can seriously increase the likelihood of implementing a chain of uranium UA. [ABSTRACT FROM AUTHOR]

Focuses on a study which analyzed the thermodynamic properties of condensed carbon in the detonation products of TNT with a statistical mechanical model. Increase in the heat of formation of diamond-like particles in detonation products; Factors that motivate the study of carbon in several mixtures; Prediction on explosive product compositions in model percent.

The article presents a narrative by the author on a discussion on arms and disarmament with scientists and strategists in Moscow, capital of the Soviet Union. A thermonuclear weapon with the equivalent power of 100 million tons of trinitrotoluene is being manufactured by Russians. Rand Corp. has estimated that a major nuclear war would likely cause the destruction of major cities and of around 90 million people in the U.S. Strategies in confronting the possibility of thermonuclear war were tackled in a study by Herman Kahn and his colleagues at Rand Corp. Kahn stressed on the importance of a civil defense program in the U.S. The need for arms control are discussed.

The article presents an analysis of the hazard associated with radioactive fallout. The first Atomic bomb which destroyed the city of Hiroshima struck out at its victims over about 7 square miles. Compared with its predecessor, the TNT, this primitive nuclear weapon resulted in the rapid development of arsenals in the different countries. Indeed, most people have scarcely begun to comprehend the meaning of Hiroshima, let alone an event which dwarfs it in significance. However, it cannot be denied that fallout adds a new dimension to the weapons of war.

The article discusses the effects of atomic bomb that releases an energy of 20,000 tons of trinitrotoluene, as in the case of the bombings in Hiroshima-shi and Nagasaki-shi in Japan. All buildings within a radius of a half mile from the bomb site will be demolished. About 85 percent of the people at a distance of one-half mile from the site will be killed. There is an approximate 100,000 casualties from the bombing in both cities. These casualties are categorized into skin burns, trauma from flying debris, and radiation sickness from gamma rays.

An Erratum to this paper has been published: https://doi.org/10.1134/S1061934823440041 [ABSTRACT FROM AUTHOR]

A novel porous polymer, denoted as tetraphenylethene-based porous polymer (PTPEK), was synthesized via a catalyst-free C–O coupling reaction. The unique combination of dipole-π interactions and π-π interactions within PTPEK facilitated exceptional adsorption property towards trinitrotoluene (TNT). Furthermore, the incorporation of tetraphenylethene groups, which exhibit aggregation-induced emission (AIE) activity, endowed PTPEK with remarkable TNT detection capability. Simultaneously, PTPEK showed excellent selective adsorption capability and outstanding selective fluorescence detection performance for TNT. At room temperature (298 K), PTPEK demonstrated a maximum TNT adsorption capacity of 209.2 mg g−1, reaching 65 % of its adsorption equilibrium within just 1 h. Additionally, PTPEK exhibited a rapid quenching time of 125 s for TNT, with a low detection limit of 4.56 × 10−6 mol/L. Notably, PTPEK also displayed excellent recyclability characteristics. [Display omitted] • A novel tetraphenylethene-based porous polymer (PTPEK) was facilely preparation. • PTPEK was proposed for adsorption and detection of TNT. • PTPEK exhibited selective adsorption capability for TNT. • PTPEK had fluorescence detection performance for TNT. • PTPEK had good recycling characteristics. [ABSTRACT FROM AUTHOR]

The detection of intact explosives in the field provides a unique challenge for investigators, considering the sensitive and dangerous nature of these samples. Handheld Raman instruments have grown in popularity for the analysis of unknown samples in the field, combining speed of data collection and reliability with a size that allows for the instruments to be field portable. Handheld Raman instruments are used commonly in the field, and yet there is very little research on the detection capabilities of these instruments, specifically for explosive compounds. The present study aimed to evaluate the detection capabilities of two handheld Raman spectrometers, the Rigaku ResQ-CQL and the Field Forensics HandyRam™, using explosives analytical standards, including 2,4,6-trinitrotoluene (TNT), nitromethane (NM), ammonium nitrate (AN) and smokeless powder components such as diphenylamine (DPA), ethyl centralite (EC), and methyl centralite (MC). The spectrometers were evaluated on their sensitivity, the repeatability of the data, and the performance of the internal library when available. In addition, an interference study with glass and plastic containers was also performed. Finally, authentic intact explosive samples, including TNT flakes, a mixture of ammonium nitrate and fuel oil (ANFO), smokeless powder and nitromethane were analyzed to evaluate the developed method and test the detection capabilities of the spectrometers with authentic samples. Spectra were reproducible for all the analytes across both instruments, with regards to the peak location and the intensity. Spectra obtained with the Rigaku ResQ-CQL displayed better resolution for all analytes, including the authentic samples. In addition, its wider scan range allowed for the detection of more detailed peaks below 400 cm−1. Identifying the detection capabilities of these handheld instruments can therefore help guide investigators on how to best utilize them in the field. [Display omitted] • Peak location and intensity of spectra were reproducible for all analytes with both spectrometers. • Rigaku ResQ-CQL showed low fluorescence and better resolution across all analytes. • Primary limitation identified of handheld spectrometers was relatively high limits of detection. • All analytes could be detected in glass and plastic containers with both spectrometers. [ABSTRACT FROM AUTHOR]

• New energetic compounds formed between picric acid, trinitrotoluene and acridine. • Structure analysis and characterization of trinitrotoluene:acridine and picric acid, acridine. • Covalent and noncovalent interactions in crystal engineering. • Visual analysis of short contacts was achieved through Hirshfeld surface analysis and associated fingerprint plots. • DFT studies were executed to investigate the frontier orbital energies, non-covalent interactions, and electrostatic potential maps. Trinitrotoluene (TNT) and picric acid (PIC) suffer from suboptimal thermal and impact sensitivities, which severely hinder their real-world use. We here demonstrate how co-crystallization with acridine (ACR) can improve these properties of TNT and PIC without detrimentally affecting their explosive performance. Remarkably, while PIC:ACR formed readily, attempts to co-crystallise TNT with ACR led to formation of new covalent bonds between the co-formers, thereby creating a new molecular entity. The structure and energetic behaviour of both novel solid forms (PIC:ACR and TNT-ACR) were characterised using a range of experimental and computational tools, indicating that both materials have improved thermal and mechanical stability but explosive performance has decreased to some extent. These findings will increase the likelihood of rational energetic material design in the future and open a new chapter in this discipline. [ABSTRACT FROM AUTHOR]

In general, chromatographic and sensor analyses have been utilized for explosive detection. The main interest on those systems is to develop a method to selectively detect explosives at a single step as well as from vapor phase if possible. Moreover, on-site and real-time detection with portable systems is another challenge for the researchers. On the other hand, the detection of 2,4,6-trinitrotoluene (TNT) vapor at the crime scene, preferably before the explosion is highly demanded in order to prevent the negative effects of terrorism and to ensure the safety of the civilian population. In this study, initially, Quartz Crystal Microbalance (QCM) sensor was prepared for real-time monitoring of TNT in aqueous solution, through the attachment of TNT peptide aptamer on the gold surface of QCM sensor. Secondly, after providing optimum conditions, TNT detection was investigated even from vapor phase through the QCM aptasensor. According to results, the selectivity coefficient of QCM-based aptasensor was calculated as 6.78 for TNT in respect to DNT whereas that was calculated as 9.02 for TNT in respect to TNB. In addition, the evaluation of the reusability and storage stability emphasized that the sensor could be used repeatedly without significant reduction in dissipation (∆D) values. The linearity coefficient (R2) was found to be 0.9965. The limit of detection (LOD) and the limit of quantitation (LOQ) were determined as 0.0238 and 0.0739 nM, respectively. The studies demonstrated that the portable QCM sensor decorated with the aptamer selective for TNT molecules could be classified as a promising alternative, selective, cost-friendly, easy-to-prepare, ready-to-use, and applicable for on-site and real-time explosive measurements (even from vapor phase). [Display omitted] • Developing a method to selectively detect explosives from both solution and vapor phases. • QCM-based aptasensor for real-time 2,4,6- trinitrotoluene (TNT) monitoring. • Promising selectivity in respect to 1,3,5-Trinitrobenzene (TNB) and 2,6-Dinitrotoluene (DNT). • Intriguing alternative approach for on-site and real-time explosive determination. [ABSTRACT FROM AUTHOR]

[Display omitted] • A portable testing setup for the detection of trinitrotoluene traces in surfaces by simply using a filter paper and a fluorescent reporter in solution with extreme sensitivity. • A modified Sylgard film useful under real conditions for qualitative fluorescent detection of hidden traces of trinitrotoluene on surfaces or fingers by a swab method. • A combination of quantitative and qualitative detection of trinitrotoluene traces on surfaces as a comprehensive new method for the detection of hidden nitroaromatic explosives in the workplace. We describe the proof of concept of a portable testing setup for the detection of trinitrotoluene (TNT), a common component in hidden explosive devices. The system allows for field-testing and generation of real-time results to test for TNT traces in surfaces by simply using a filter paper and a fluorescent reporter. In this way, the controlled trapping and detection of the analyte by a chemical sensor gives reliable results at extremely low concentrations of TNT on surfaces under real life conditions suitable for daily use in ordinary sampling for example at airlines luggage storage or sport locker rooms. The reported fluorescent methodology is very sensitive and selective, allowing for the trapping and detection of TNT by a fluorescent reporter to give reliable results at very low concentrations. As a complement, we report the preparation of a modified Sylgard film that is useful under real conditions for qualitative fluorescent detection of hidden traces of TNT on surfaces or fingers by a swab method. The combination of quantitative and qualitative detection of TNT traces on surfaces constitutes a comprehensive new method for the detection of hidden nitroaromatic explosives in the workplace. [ABSTRACT FROM AUTHOR]

Abstract: The review covers the strategies for the biodegradation of a dangerous pollutant of the environment, an explosive 2,4,6-trinitrotoluene. The characteristics of the metabolism of this compound in microorganisms under aerobic and anaerobic conditions and the main enzymes involved in the transformation are described. The main class of enzymes involved in the destruction of trinitrotoluene are nitroreductases; oxidases, hydrogenases, and peroxidases may also be involved in degradation. Several approaches to the biodegradation of trinitrotoluene in the environment have been singled out and discussed: bioaugmentation of the biomass of TNT-destructor strains and consortia of microorganisms that degrade this compound; stimulation of the autochthonous microflora of polluted natural environments via the introduction of additional substrates for microorganism growth and electron donors for the reduction of trinitrotoluene; pollutant biodegradation by immobilized cells of microorganisms in bioreactors and biofilters; phytoremediation and the application of preventive measures consisting of the introduction of spores and lyophilisates of bacteria with biodegradation activity in a mixture containing nitroaromatic compounds. [ABSTRACT FROM AUTHOR]

The explosive xenobiotic 2,4,6-trinitrotoluene (TNT) is a major worldwide environmental pollutant and its persistence in the environment presents health and environmental concerns. The chemical structure of TNT dictates that biological detoxification pathways follow predominantly reductive transformation of the nitro groups, and as a result, TNT is notoriously recalcitrant to mineralization in the environment. Plant-based technologies to remediate this toxic pollutant rely on a solid understanding of the biochemical detoxification pathways involved. Toward this, two Arabidopsis Tau class glutathione transferases, GSTU24 and GSTU25, have been identified that catalyze the formation of three TNT-glutathionylated conjugates. These two GSTs share 79% identity yet only GSTU25 catalyzes the substitution of a nitro group for sulfur to form 2-glutathionyl-4,6-dinitrotoluene. The production of this compound is of interest because substitution of a nitro group could lead to destabilization of the aromatic ring, enabling subsequent biodegradation. To identify target amino acids within GSTU25 that might be involved in the formation of 2-glutathionyl-4,6-dinitrotoluene, the structure for GSTU25 was determined, in complex with oxidized glutathione, and used to inform site-directed mutagenesis studies. Replacement of five amino acids in GSTU24 established a conjugate profile and activity similar to that found in GSTU25. These findings contribute to the development of plant-based remediation strategies for the detoxification of TNT in the environment. [ABSTRACT FROM AUTHOR]

Background: The health and resilience of species in natural environments is increasingly challenged by complex anthropogenic stressor combinations including climate change, habitat encroachment, and chemical contamination. To better understand impacts of these stressors we examined the individual- and combined-stressor impacts of malaria infection, food limitation, and 2,4,6-trinitrotoluene (TNT) exposures on gene expression in livers of Western fence lizards (WFL, Sceloporus occidentalis) using custom WFL transcriptome-based microarrays. Results: Computational analysis including annotation enrichment and correlation analysis identified putative functional mechanisms linking transcript expression and toxicological phenotypes. TNT exposure increased transcript expression for genes involved in erythropoiesis, potentially in response to TNT-induced anemia and/or methemoglobinemia and caused dose-specific effects on genes involved in lipid and overall energy metabolism consistent with a hormesis response of growth stimulation at low doses and adverse decreases in lizard growth at high doses. Functional enrichment results were indicative of inhibited potential for lipid mobilization and catabolism in TNT exposures which corresponded with increased inguinal fat weights and was suggestive of a decreased overall energy budget. Malaria infection elicited enriched expression of multiple immune-related functions likely corresponding to increased white blood cell (WBC) counts. Food limitation alone enriched functions related to cellular energy production and decreased expression of immune responses consistent with a decrease in WBC levels. Conclusions: Despite these findings, the lizards demonstrated immune resilience to malaria infection under food limitation with transcriptional results indicating a fully competent immune response to malaria, even under bio-energetic constraints. Interestingly, both TNT and malaria individually increased transcriptional expression of immune-related genes and increased overall WBC concentrations in blood; responses that were retained in the TNT x malaria combined exposure. The results demonstrate complex and sometimes unexpected responses to multiple stressors where the lizards displayed remarkable resiliency to the stressor combinations investigated. [ABSTRACT FROM AUTHOR]

Microbiome studies focused on ecologically relevant vertebrate models like reptiles have been limited. Because of their relatively small home range, fast maturation, and high fecundity, lizards are an excellent reptilian terrestrial indicator species. For this study we used the green anole, Anolis carolinensis, to assess the impact of military relevant contaminants on fecal microbiome composition. Fourteen day sub-acute exposures were conducted via oral gavage with 2,4,6-Trinitrotoluene (TNT) and inorganic lead at doses of 60 mg/kg and 20 mg/kg of body weight, respectively. Body weights and food consumption were monitored and fecal samples were collected for high-throughput 16S rRNA gene amplicon sequencing and analytical chemistry at days 0 and 15. At the end of the study, liver and gut were harvested for body burden data. Chemical analysis confirmed accumulation of TNT, TNT transformation products, and lead in liver tissue and fecal samples. Bacterial community analysis of fecal material revealed significant differences between day 0 and day 15 of TNT exposed anoles with an operational taxonomic unit (OTU) within the genus Erwinia representing 32% of the microbial community in TNT exposed anoles. Predictable changes in gut microbiome composition could offer an easily assayed, noninvasive biomarker for specific chemical exposure providing enhanced scientific support to risk assessments on military installations. [ABSTRACT FROM AUTHOR]

In this work the authors intended to improve the knowledge regarding to RC and masonry structures subjected to blast loading. A further aim is to describe and use the non-linear-finite element method through a comparison of RC building with and without infill wall. In order to perform the models subjected to analysis, based on existing experimental studies of infill wall and RC columns, by using the FE method, the blast loading is simulated using conventional weapons for explosion model where it was generated with 1000kg of TNT explosive material at a distance of 4.6m. For the finite element model of the building, bricks and mortar joints are represented by continuously cohesive elements and contact elements were used to simulate the adhesion and interaction between the blocks. The nonlinear behavior of the concrete and masonry were simulated using the Coupled Damage Plasticity methods. Simulation results showed that compressive and tensile strengths increase due to the strain rate effect and the initial stiffness increases. [ABSTRACT FROM AUTHOR]

Abstract A znic fluorescence framework {[(Zn 2 (BDPO)·3H 2 O]·H 2 O} n (1) (H 4 BDPO = N , N ′-Bis(3,5-discarboxyphenyl)oxalamide) was successfully synthesized and characterized. Complex 1 is a 2D sheet [Zn 2 (BDPO)] n , the H-bondings and π···π interactions extend the 2D sheet into 3D supermolecular framework. Importantly, it is a rarely reported highly selective and sensitive luminescence MOF sensor for detecting 2,4,6-Trinitroluene(TNT) and Fe(III) simultaneously through fluorescence quenching. Furthermore, the sensing mechanisms are mainly attributed to the photo-induced electron transfer and competitive absorptions between the excitation/emission of 1 and analytes. Graphical abstract A new Zn(II)-MOF was synthesized and structurally characterized. Complex 1 is promising bifunctional luminescent sesnor for highly selective and sensitive sensing TNT and Fe3+ ions through luminescence quenching effect. The quenching mechanisms were studied based on both experiments and calculation. Unlabelled Image Highlights • A new Zn-luminescence coordination polymer was synthesized and characterized, the structures were analyzed in detail. • Fluorescent sensing experiment exhibits complex 1 has high sensitivity for sensing nitro aromatic explosive TNT. • Fluorescent sensing experiment also exhibits complex 1 has high selectivity for detecting Fe3+ ion. • The detection mechanisms and recyclability were studied based on both experiments and calculation. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this work is detection of trinitrotoluene (TNT) using aptamer as a new sensing strategy. Two pBluescript plasmids containing RT and ST anti-TNT aptamers were used as templates for aptamer amplification by PCR method. For this purpose, 126 bp ST-aptamer and 118 bp RT-aptamer were amplified using specific primers. TNT bound to bovine serum albumin (TNP-BSA) was used as the antigen, and digoxigenin (DIG)-labeled aptamers were detected by horseradish peroxidase conjugated to anti-DIG monoclonal antibodies. The sensitivity and specificity of ST- and RT-aptamers were determined using optimized PCR and enzyme-linked aptamer-sorbent assay. The sensitivity of this detection after optimization was determined about 1.76 nM of TNT using 1 pM of aptamers. These results indicated favorable functions of both aptamers for TNT detection that can be used in the future as aptasensors for investigation and utilization of the TNT identification. [ABSTRACT FROM AUTHOR]

This letter demonstrates a possibility to overcome the polarization-dependent problem in surface enhanced Raman scattering (SERS) performance by two-dimensional (2D) sinusoidal silver grating. A reproducible SERS substrate with a large area can be easily fabricated by maskless laser interference photolithography. The polarization-independent SERS performance and SERS enhancement factor (EF) of this substrate are deduced by finite difference time domain and demonstrated by R6G SERS detection experiments. SERS performance of 2D sinusoidal grating is polarization-independent over the whole 360° and EF can be 5 orders of magnitude as possible. Moreover, this long-range SERS substrate can realize label-free SERS detection of 2,4,6-Trinitrotoluene (TNT). [ABSTRACT FROM AUTHOR]

We show the results of simultaneous measurements of the brightness temperature and the detonation-front motion in a trinitrotoluene sample. The measurements were performed using the EHF radiointerferometer radiometer developed at Yu. E. Sedakov Research Institute of Measurement Systems. The algorithms and the methods for the recorded-signal processing are described. [ABSTRACT FROM AUTHOR]

A multifunctional Infrared (IR) parametric laser system for standoff detection and identification of trace atmospheric gases, including explosives and chemically aggressive substances has been developed and tested. The method can detect vapors of condensed explosives. Computational and experimental studies on the standoff determination of spectroscopic parameters of known explosives such as TNT, RDX, and PETN have been performed. It has been shown that the multifunctional IR optical parametric oscillator is suitable for high-sensitivity detection (∼1 ppm) of these substances using the method of differential absorption and scattering. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Secondary electrospray ionization-ion mobility spectrometry was utilized for the determination of TNT. • KCl was selected as the most effective dopant in electrospray solution for signal enhancement. • The proposed method was used for determination of TNT, extracted from water samples by DLLME. Abstract In this study, secondary electrospray ionization source (SESI) was coupled with ion mobility spectrometer (IMS) and utilized for the determination of 2,4,6-trinitrotoluene (TNT) in water and wastewater samples. The sensitivity of SESI–IMS for TNT detection was compared with that obtained by ESI–IMS. The effect of different halide ions (as dopants) on the signal enhancement was evaluated and eventually KCl was selected as the most effective dopant. Sample preparation step for the pre-concentration of TNT was performed by dispersive liquid-liquid microextraction using an extraction solvent with the lower density than water. Methanol and toluene were selected as the disperser and extraction solvents, respectively. Some other affected parameters on the extraction efficiency; such as salt addition and sample acidity were also investigated. The linearity was obtained 4.0–175.0 μg L−1 and the limit of detection and quantification were calculated 1.0 and 4.0 μg L−1, respectively. Tap, River, and laboratory wastewater samples were selected to evaluate the method capability for determining the analyte in real matrices, and satisfactory analytical results were obtained. [ABSTRACT FROM AUTHOR]

A novel high-efficiency composite photocatalyst, carbon quantum dots (CQDs) are embedded onto out-surface surface of the TiO 2 nanotubes (TNTs) with high percentage of photocatalytic reactive facets, was fabricated through an improved hydrothermal method. The characterization results showed that the CQDs was chemically adhered to out-surface of the TNTs through the C O and/or C O bonds formed between the CQDs and TNTs. The photocatalytic performance of as-prepared photocatalysts was evaluated to degrade methylene blue (MB) solution under the visible light. The as-prepared photocatalysts had a marvelous photocatalytic performance and the CQDs/TNTs-0.2 sample had the best photocatalytic performance with a decolorization rate of 91.3% and approximately 2 times more than that of pure TNTs for the high initial concentration of MB solution (30 mg/l) within 50 min under visible-light irradiation. The CQDs with excellent Up-Conversion Photoluminescence(UCPL)properties as co-catalysts can covert long wavelength light (>600 nm) absorbed from infrared light into visible light (<600 nm), which activates the TNTs to produce electron-hole pairs. Moreover, the CQDs also can capture the photoexcited electrons and prolong the lifetime of the photoexcited charges. In addition, the stacking interaction of the π-π bonds between the CQDs and the dyes of the benzene ring structure would be beneficial for enhancing the absorption performance of the CQDs/TNTs photocatalysts. The photocatalytic mechanism and process have also been discussed in detail according to the characterization and photodegradation results. This work is of great interest to introduce a new visible-light photocatalyst for the treatment of organic wastewater and protect environment. [ABSTRACT FROM AUTHOR]

Abstract Bioaccumulation of 2,4,6-trinitrotoluene (TNT) and its main metabolites 2-amino-4,6-dinitrotoluene (2-ADNT) and 4-amino-2,6-dinitrotoluene (4-ADNT) leaking from corroded munitions at a munitions dumping site (Kolberger Heide, Germany) was evaluated in transplanted blue mussels (Mytilus edulis). Six moorings with mussel bags were placed east and west at varying positions near the mine mound. In order to monitor any differences resulting from changing seasons, three exposure times were chosen. First exposure period: April–July 2016 (106 days); second exposure period: July–December 2016 (146 days); third exposure period: December 2016–March 2017 (92 days). We found amounts of 4-ADNT in mussel tissue ranging from 2.40 ± 2.13 to 7.76 ± 1.97 ng/(g mussel wet weight). Neither TNT nor 2-ADNT could be detected. Considering seasonal differences, orientation and distances of the moorings to the mine mound no correlation between levels in mussel tissue was evident. Graphical abstract Unlabelled Image Highlights • Explosives leaking from corroded munition might concentrate in marine biota. • The TNT metabolite 4-ADNT accumulates in the tissue of transplanted blue mussels. • Seasonal differences do not alter 4-ADNT levels in mussel tissue. • Increasing distance of mussels to the mine mound did not decrease 4-ADNT levels. • Explosives from corroded munition may pose a risk to human health and environment. [ABSTRACT FROM AUTHOR]

Chemical sensors for the rapid and selective detection of explosives such as 2,4,6-trinitrotoluene (TNT) are very important. In order to find efficient sensors with enhanced performance for nitro-aromatics, a series of IRMOFs with different pillaring ligands but the same network topology was examined. The fluorescence sensing ability of these compounds towards nitrobenzene (NB), 1,3-dinitrobenzene (1,3-DNB), 2,4-dinitrotoluene (2,4-DNT) and 2,4,6-trinitrotoluene (TNT) was investigated. These compounds have great potential for the detection of TNT. The limit of detection (LOD) for TNT is 112, 261, 833 and 1070 nM for TMU-6(L1), TMU-21(L2), TMU-6(RL1) and TMU-21(RL2), respectively. The LOD of TMU-21(RL2) is among the highest values reported in the literature for sensing TNT. The results highlight both the importance of functionality on the pillaring ligands as well as the hydrophilic/hydrophobic nature of the framework pores for the potential of MOFs for the detection of nitro-aromatics. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The antimonene nanosheet device (AMD) is designed and used for adsorption of explosive vapors. • The magnitude of current varies in the order of 10−11–10−7 A upon adsorption of vapors on AMD. • The results suggest that the distinction of four explosive vapors is possible using AMD device. Abstract The recent advances in the molecular device fabrication have outstretched the exciting applications in vapor sensing devices. This report investigates the explosive vapor detection using the antimonene molecular device (AMD) implemented with the first-principles study. The adsorption of four different explosive vapors namely hexanitrostilbene, M-dinitrobenzene, picric acid, and 2,4,6-trinitrotoluene on AMD device is examined. The adsorption configurations, charge transfer, band gap variation of antimonene nanosheet upon adsorption of explosive vapors on AMD are studied. The adsorption of vapors on AMD device is supported with the transmission spectrum and current-voltage features. Further, the results suggest that next-generation nanosensor is conceivable using antimonene nanosheets. [ABSTRACT FROM AUTHOR]

A 1:1 cocrystal of TNT and 1-amino-4-bromonaphthalene was prepared via solvent evaporation. The structure of the cocrystal was determined via single-crystal and powder X-ray diffraction. Crystal structure determination studies indicated that the main mechanism of cocrystallization originates from the intermolecular hydrogen bonding (amino- nitro), halogen bonding, and π - π stacking. Investigation of intermolecular interactions by Hirshfeld surface and fingerprint plot analysis revealed that the structures were stabilized by H...H, O...H, C...C (π-π) and Br...O interactions. Hirshfeld surfaces showed that these weak interactions were significant for crystal packing. We analyzed the crystal packing and showed how this may influence sensitivity to impact. The TNT:1-amino-4-bromonaphthalene cocrystal displays significantly reduced impact sensitivity relative to pure TNT, indicating for the first time that a new TNT cocrystal was less sensitive to impact than pure TNT component. This difference in impact sensitivities may arise from the considerably different intermolecular interactions seen in the cocrystal structure. The results highlight that cocrystallization is an effective way to alter the impact sensitivity, detonation performance, decomposition temperature, melting point, oxygen balance, crystal packing, and the density of explosives. [ABSTRACT FROM AUTHOR]

This article serves as a short preview to the history o f roadblocks (road obstacles), and also as an outlook to modern and future technologies, and challenges they face in this particular field o f science. At this moment, it is a real problem to stop the car immediately (if possible), before it causes damages, or threats any civil or military objects. It does not necessarily have to be only an accident, it can be a terrorist attack, which can cause enormous collateral damage and also life losses. The contemporary problem is not only the combat with fire explosive systems, but it is also important to focus on avoiding damaging o f important devices, road objects or spots called "soft targets". A ll this combined presents the essential challenge for roadblocks development. [ABSTRACT FROM AUTHOR]

A composite one-dimensional (1D) Ag sinusoidal nanograting aiming at label-free surface enhanced Raman scattering (SERS) detection of TNT with robust and reproducible enhancements is discussed. 1D periodic sinusoidal SiO2 grating followed by Ag evaporation is proposed for the creation of reproducible and effective SERS substrate based on surface plasmon polaritons (SPPs). The optimal structure of 1D sinusoidal nanograting and its long-range SERS effect are analyzed by using the finite difference time domain (FDTD). Simulation SERS enhancement factor (EF) can be 5 orders of magnitude as possible. This SERS substrate is prepared by the interference photolithography technology, its SERS performance is tested by Rh6G detection experiments, and the actual test EF is about 104. The label-free SERS detection capacity of TNT is demonstrated in the experiment. [ABSTRACT FROM AUTHOR]

The thermal behavior and decomposition kinetics of a melt cast composition based on mixture of bicyclic nitramine, cis-1,3,4,6-tetranitrooctahydroimidazo-[4,5- d ]imidazole (BCHMX) and insensitive explosive, 2,4,6-trinitrotoluene (TNT) (60/40 by wt %) have been investigated. This behavior was studied by non-isothermal TG and DSC techniques and the decomposition kinetics were determined by the isoconversional methods named Kissinger and modified Kissinger-Akahira-Sunose (KAS). For comparison, the traditional TNT casted compositions based on 1,3,5-trinitro-1,3,5-triazinane (RDX) named composition B and β-1,3,5,7-tetranitro-1,3,5,7-tetrazocane (β-HMX) were studied. Also Vacuum Stability Test (VST) was used isothermally at 120 °C for six hours to determine the specific rate constants. Despite of the volatility of TNT, the obtained results showed that the reactivity of the studied cyclic nitramines in mixtures was increased in the order HMX < BCHMX < RDX, because of their incorporation into the melted TNT (acidic solvent). The kinetic compensation effect and outputs of the Vacuum Stability Test clearly exemplify this reactivity. Nevertheless, taking into consideration the recently published facts about this composition and its application in practice, the mixture is a promising composition which has high relative explosive strength compared with the other studied compositions. [ABSTRACT FROM AUTHOR]