The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Jennifer Weidhaas - One of the best experts on this subject based on the ideXlab platform.
-
biodegradation of imx 101 explosive formulation constituents 2 4 dinitroanisole dnan 3 nitro 1 2 4 triazol 5 one nto and Nitroguanidine
Journal of Hazardous Materials, 2014Co-Authors: Thomas Richard, Jennifer WeidhaasAbstract:Abstract Defense agencies are increasingly using insensitive munitions (IM) in place of explosives such as 2,4,6-trinitrotoluene. In this study simultaneous aerobic degradation of the IMX-101 formulation constituents 2,4-dinitroanisole (DNAN), 3-nitro-1,2,4-triazol-5-one (NTO), and Nitroguanidine (NQ) was observed and degradation products were examined. Degradation products over four days of incubation included: nitrourea, 1,2-dihydro-3H-1,2,4-triazol-3-one, and 2,4-dinitrophenol. The enrichment culture maximum specific growth rate of 0.12 h −1 and half saturation constant of 288 mg L −1 during degradation of IMX-101 as a sole nitrogen source suggest that enrichment culture growth kinetics may closely relate to those of other explosive and nitroaromatic compounds.
-
dissolution sorption and phytoremediation of imx 101 explosive formulation constituents 2 4 dinitroanisole dnan 3 nitro 1 2 4 triazol 5 one nto and Nitroguanidine
Journal of Hazardous Materials, 2014Co-Authors: Thomas Richard, Jennifer WeidhaasAbstract:Abstract The insensitive munition, IMX-101 approved for use in the USA, contains 2,4-dinitroanisole (DNAN), 3-nitro-1,2,4-triazol-5-one (NTO), and Nitroguanidine (NQ) and is designed to be less sensitive to shock and sympathetic detonation. Given the estimated future use of IMX-101, an understanding of IMX-101 constituent attenuation mechanisms on testing and training ranges is needed. Studies were conducted to determine (1) the rates of IMX-101 fragment dissolution during simulated rainfall, (2) DNAN and NTO soil sorption coefficients, (3) ability of grasses to germinate in and phytoremediate IMX-101 contaminated soil, and (4) effect of the addition of IMX-101 degrading enrichment cultures on phytoremediation. The IMX-101 particles were found to dissolve slowly under simulated rainfall conditions with NQ and NTO dissolving first, leaving DNAN crystals. DNAN and NTO sorption to soils fit Freundlich isotherms and limited desorption was observed. DNAN and NQ were shown to be taken up into the roots and shoots of a mixture of big bluestem grass (Andropogon gerardii), Nash Indiangrass (Sorghastrum nutans), and switchgrass (Panicum virgatum) during phytoremediation of soils contaminated with up to 50 mg kg−1 IMX-101. Complete degradation of IMX-101 to below detection limits occurred over 225 days. The addition of an IMX-101 degrading enrichment culture to the treatments significantly increased the root and shoot mass.
Thomas Richard - One of the best experts on this subject based on the ideXlab platform.
-
biodegradation of imx 101 explosive formulation constituents 2 4 dinitroanisole dnan 3 nitro 1 2 4 triazol 5 one nto and Nitroguanidine
Journal of Hazardous Materials, 2014Co-Authors: Thomas Richard, Jennifer WeidhaasAbstract:Abstract Defense agencies are increasingly using insensitive munitions (IM) in place of explosives such as 2,4,6-trinitrotoluene. In this study simultaneous aerobic degradation of the IMX-101 formulation constituents 2,4-dinitroanisole (DNAN), 3-nitro-1,2,4-triazol-5-one (NTO), and Nitroguanidine (NQ) was observed and degradation products were examined. Degradation products over four days of incubation included: nitrourea, 1,2-dihydro-3H-1,2,4-triazol-3-one, and 2,4-dinitrophenol. The enrichment culture maximum specific growth rate of 0.12 h −1 and half saturation constant of 288 mg L −1 during degradation of IMX-101 as a sole nitrogen source suggest that enrichment culture growth kinetics may closely relate to those of other explosive and nitroaromatic compounds.
-
dissolution sorption and phytoremediation of imx 101 explosive formulation constituents 2 4 dinitroanisole dnan 3 nitro 1 2 4 triazol 5 one nto and Nitroguanidine
Journal of Hazardous Materials, 2014Co-Authors: Thomas Richard, Jennifer WeidhaasAbstract:Abstract The insensitive munition, IMX-101 approved for use in the USA, contains 2,4-dinitroanisole (DNAN), 3-nitro-1,2,4-triazol-5-one (NTO), and Nitroguanidine (NQ) and is designed to be less sensitive to shock and sympathetic detonation. Given the estimated future use of IMX-101, an understanding of IMX-101 constituent attenuation mechanisms on testing and training ranges is needed. Studies were conducted to determine (1) the rates of IMX-101 fragment dissolution during simulated rainfall, (2) DNAN and NTO soil sorption coefficients, (3) ability of grasses to germinate in and phytoremediate IMX-101 contaminated soil, and (4) effect of the addition of IMX-101 degrading enrichment cultures on phytoremediation. The IMX-101 particles were found to dissolve slowly under simulated rainfall conditions with NQ and NTO dissolving first, leaving DNAN crystals. DNAN and NTO sorption to soils fit Freundlich isotherms and limited desorption was observed. DNAN and NQ were shown to be taken up into the roots and shoots of a mixture of big bluestem grass (Andropogon gerardii), Nash Indiangrass (Sorghastrum nutans), and switchgrass (Panicum virgatum) during phytoremediation of soils contaminated with up to 50 mg kg−1 IMX-101. Complete degradation of IMX-101 to below detection limits occurred over 225 days. The addition of an IMX-101 degrading enrichment culture to the treatments significantly increased the root and shoot mass.
Pauline I Tolmach - One of the best experts on this subject based on the ideXlab platform.
-
estimation of the thermodynamic properties of Nitroguanidine hexahydro 1 3 5 trinitro 1 3 5 triazine and octahydro 1 3 5 7 tetranitro 1 3 5 7 tetrazocine in the gas phase
Thermochimica Acta, 1994Co-Authors: O V Dorofeeva, Pauline I TolmachAbstract:Abstract Thermodynamic properties of Nitroguanidine, hexahydro-1,3,5-trinitro-1,3,5-triazine and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine in the gas phase have been estimated using additivity techniques and statistical calculations. Ideal gas thermodynamic properties of urea, guanidine, methanimine, 2-propanimine, nitramide, N-methyl-N-nitromethanamine and 1,3,5-triazine required for these estimations were calculated by rigid-rotor harmonic-oscillator approximation using the molecular constants available from the literature. Estimations obtained by the difference method in addition to statistical calculations give satisfactory values of thermodynamic properties.
T A Novikova - One of the best experts on this subject based on the ideXlab platform.
-
1 amino 2 Nitroguanidine in reactions with α ketocarboxylic acids
Chemistry of Heterocyclic Compounds, 2020Co-Authors: Olga Yu Ozerova, T P Efimova, T A NovikovaAbstract:The reactions of 1-amino-2-Nitroguanidine with α-ketocarboxylic acids gave substituted hydrazones of α-ketocarboxylic acids, the cyclization of which depended on the geometry of the azomethine moiety. It was established that the obtained hydrazones were able to form a 1,2,4-triazine system in the case when the hydrazone of its linear precursor existed in the form of Z(syn)-isomer. Thus, the phenylglyoxalic acid hydrazone, the azomethine moiety of which existed in the Z-form, underwent heterocyclization with the formation of substituted 3-nitroimino-6-phenyl-4,5-dihydro-1,2,4-triazin-5(2Н)-one, while hydrazones of glyoxalic and methylglyoxalic acids, which existed in the E-configuration, did not participate in this reaction.
-
synthesis of new nitroamino containing 1 2 4 triazines by reaction of 1 amino 2 Nitroguanidine with α diketones
Russian Journal of General Chemistry, 2018Co-Authors: Yu O Ozerova, T P Efimova, T A NovikovaAbstract:The reaction of 1-amino-2-Nitroguanidine with α-diketones (butane-2,3-dione and 1,2-diphenylethanedione) produced new specimens of nitroamino-containing 1,2,4-triazines. The structure of the synthesized compounds of linear and heterocyclic series was confirmed by 1H, 13C{1H} NMR, IR, and UV spectra.
-
reactions of 1 amino 2 Nitroguanidine with glyoxal
Russian Journal of General Chemistry, 2015Co-Authors: Yu O Ozerova, T P Efimova, T A Novikova, V M BerestovitskayaAbstract:The reactions of 1-amino-2-Nitroguanidine with glyoxal under conditions of acidic and alkaline catalysis have been comprehensively studied. The obtained glyoxal dihydrazone, 3-nitroamino-1,2,4-triazine sodium salt, 5-hydroxy-4,5-dihydro-3-nitroamino-1,2,4-triazine, and its 5-alkoxy- and 5-aminonitroguanidyl derivatives (products of the reactions with 1-amino-2-Nitroguanidine and alcohols) have been characterized by 1H, 13C–{1H} NMR, IR, and UV spectroscopy methods.
-
structure and synthesis of 3 5 dimethyl n nitro 1h pyrazole 1 carboxamidine
Russian Journal of General Chemistry, 2015Co-Authors: Yu O Ozerova, T P Efimova, T A Novikova, V V Gurzhii, V M BerestovitskayaAbstract:A new approach to the synthesis of 3,5-dimethyl-N-nitro-1H-pyrazole-1-carboxamidine was developed based on condensing 1-amino-2-Nitroguanidine with pentane-2,4-dione under alkaline catalysis. The known method of its preparation in the presence of acetic acid was improved. The structure of 3,5-dimethyl-N-nitro-1H-pyrazole-1-carboxamidine was characterized by NMR, IR spectroscopy and X-ray diffraction analysis.
-
Reactions of 1-amino-2-Nitroguanidine with 2-aryl(hetaryl)-1-nitro-1-ethoxycarbonyl(benzoyl)ethenes
Russian Journal of General Chemistry, 2014Co-Authors: T P Efimova, T A Novikova, O. Yu. Ozerova, R. I. Baichurin, V M BerestovitskayaAbstract:Reactions of 1-amino-2-Nitroguanidine with 2-aryl(hetaryl)-1-nitro-1-ethoxycarbonyl(benzoyl)-ethenes proceed via initial formation the aza-Michael product, are accompanied by liberation of nitroacetic ester (or nitroacetophenone), and result in N -aryl(hetaryl)methylidene- N -(2-nitroguanidino)amines.
Kurt A Gust - One of the best experts on this subject based on the ideXlab platform.
-
Multi-species Aquatic Toxicity Assessment of 1-Methyl-3-Nitroguanidine (MeNQ)
Archives of Environmental Contamination and Toxicology, 2021Co-Authors: Guilherme R Lotufo, Kurt A Gust, Mark L Ballentine, Lee C Moores, Lauren R. May, Pornsawan ChappellAbstract:The Army is replacing traditional munitions with insensitive munitions (IM) resistant to accidental detonation. The aquatic toxicity of 1-methyl-3-Nitroguanidine (MeNQ), which is being assessed for potential use in IM formulations, remains largely untested. The present study fills a number of critical data gaps for MeNQ aquatic toxicity by evaluating effects across two vertebrate and five invertebrate species. Specifically, responses in larval Pimephales promelas , Rana pipiens tadpoles, Chironomus dilutus , Lumbriculus variegatus , Hydra littoralis , Hyalella azteca , and Daphnia pulex were assessed in MeNQ exposures across various acute, subchronic, and chronic bioassays. Overall, survival was unaffected in most of the MeNQ exposures where significant lethal effects were only observed in D. pulex , H. littoralis , and C. dilutus and only at concentrations ≥ 2186 mg/L. Significant sublethal effects on growth were observed for C. dilutus at 903 mg/L and H. azteca at 1098 mg/L in 10-d assays. Significantly decreased reproduction was observed at 2775 mg/L for H. azteca in a chronic 35-d assay and at 174 mg/L for D. pulex in the 11-d three-brood assay representing a sublethal effect one order of magnitude more sensitive than the effective lethal concentration for D. pulex (2987 mg/L). Degradation of MeNQ in ultraviolet light (UV) greatly increased toxicity to D. pulex . Specifically, exposure to a MeNQ solution that was completely UV-degraded prior to D. pulex exposures resulted in an 11-d LC50 of 6.1 mg/L and a 50% reduction in reproduction at 3.125 mg/L, based on the original MeNQ parent-compound concentrations.
-
comparative toxicological evaluation of uv degraded versus parent insensitive munition compound 1 methyl 3 Nitroguanidine in fathead minnow
Environmental Toxicology and Chemistry, 2020Co-Authors: Guilherme R Lotufo, Kurt A Gust, Mark L Ballentine, Lee C Moores, Alan J Kennedy, Natalie D Barker, Pornsawan ChappellAbstract:The US Army is replacing traditional munitions with insensitive munitions resistant to accidental detonation. Although the parent insensitive munition compound Nitroguanidine (NQ) is generally not acutely toxic at concentrations >1000 mg/L in aquatic exposures, products formed by intensive ultraviolet (UV) degradation resulted in multiple-order of magnitude increases in toxicity. A methylated congener of NQ, 1-methyl-3-Nitroguanidine (MeNQ), is also being assessed for potential use in insensitive munition explosive formulations; therefore, the present study investigated the hazard of parent versus UV-degraded MeNQ using fathead minnows (Pimephales promelas). Although up to 716 mg/L parent MeNQ caused no significant mortality or effects on growth in larval P. promelas fish in 7-d exposures, a similar concentration of MeNQ subjected to UV treatment resulted in 85% mortality. The UV treatment degraded only 3.3% of the MeNQ (5800 mg/L stock, UV-treated for 6 h), indicating that MeNQ degradation products have potentially high toxicity. The parent MeNQ exposure caused significantly decreased transcriptional expression of genes within the significantly enriched insulin metabolic pathway, suggesting antagonism of bioenergetics pathways, which complements observed, although nonsignificant, decreases in body weight. Significant differential transcriptional expression in the UV-degraded MeNQ treatments resulted in significant enrichment of pathways and functions related to the cell cycle, as well as erythrocyte function involved in O2 /CO2 exchange. These functions represent potential mechanistic sources of increased toxicity observed in the UV-degraded MeNQ exposures, which are distinct from previously observed mechanisms underlying increased toxicity of UV-degraded NQ in fish. Environ Toxicol Chem 2020;39:612-622. © 2019 SETAC.
-
comparative toxicogenomics of three insensitive munitions constituents 2 4 dinitroanisole Nitroguanidine and nitrotriazolone in the soil nematode caenorhabditis elegans
BMC Systems Biology, 2018Co-Authors: Ping Gong, Natalie D Barker, Mitchell S Wilbanks, Keri B Donohue, Anne M Mayo, Yuping Wang, Huixiao Hong, Xin Guan, Kurt A GustAbstract:Ecotoxicological studies on the insensitive munitions formulation IMX-101 and its components 2,4-dinitroanisole (DNAN), Nitroguanidine (NQ) and nitrotriazolone (NTO) in various organisms showed that DNAN was the main contributor to the overall toxicity of IMX-101 and suggested that the three compounds acted independently. These results motivated this toxicogenomics study to discern toxicological mechanisms for these compounds at the molecular level. Here we used the soil nematode Caenorhabditis elegans, a well-characterized genomics model, as the test organism and a species-specific, transcriptome-wide 44 K-oligo probe microarray for gene expression analysis. In addition to the control treatment, C. elegans were exposed for 24 h to 6 concentrations of DNAN (1.95–62.5 ppm) or NQ (83–2667 ppm) or 5 concentrations of NTO (187–3000 ppm) with ten replicates per treatment. The nematodes were transferred to a clean environment after exposure. Reproduction endpoints (egg and larvae counts) were measured at three time points (i.e., 24-, 48- and 72-h). Gene expression profiling was performed immediately after 24-h exposure to each chemical at the lowest, medium and highest concentrations plus the control with four replicates per treatment. Statistical analyses indicated that chemical treatment did not significantly affect nematode reproduction but did induce 2175, 378, and 118 differentially expressed genes (DEGs) in NQ-, DNAN-, and NTO-treated nematodes, respectively. Bioinformatic analysis indicated that the three compounds shared both DEGs and DEG-mapped Reactome pathways. Gene set enrichment analysis further demonstrated that DNAN and NTO significantly altered 12 and 6 KEGG pathways, separately, with three pathways in common. NTO mainly affected carbohydrate, amino acid and xenobiotics metabolism while DNAN disrupted protein processing, ABC transporters and several signal transduction pathways. NQ-induced DEGs were mapped to a wide variety of metabolism, cell cycle, immune system and extracellular matrix organization pathways. Despite the absence of significant effects on apical reproduction endpoints, DNAN, NTO and NQ caused significant alterations in gene expression and pathways at 1.95 ppm, 187 ppm and 83 ppm, respectively. This study provided supporting evidence that the three chemicals may exert independent toxicity by acting on distinct molecular targets and pathways.
-
the increased toxicity of uv degraded Nitroguanidine and imx 101 to zebrafish larvae evidence implicating oxidative stress
Aquatic Toxicology, 2017Co-Authors: Kurt A Gust, Lee C Moores, Alan J Kennedy, Pornsawan Chappell, Jacob K Stanley, Mitchell S Wilbanks, Michael L Mayo, Shinita M Jordan, Natalie D BarkerAbstract:Insensitive munitions (IMs) improve soldier safety by decreasing sympathetic detonation during training and use in theatre. IMs are being increasingly deployed, although the environmental effects of IM constituents such as Nitroguanidine (NQ) and IM mixture formulations such as IMX-101 remain largely unknown. In the present study, we investigated the acute (96h) toxicity of NQ and IMX-101 to zebrafish larvae (21d post-fertilization), both in the parent materials and after the materials had been irradiated with environmentally-relevant levels of ultraviolet (UV) light. The UV-treatment increased the toxicity of NQ by 17-fold (LC50 decreased from 1323mg/L to 77.2mg/L). Similarly, UV-treatment increased the toxicity of IMX-101 by nearly two fold (LC50 decreased from 131.3 to 67.6mg/L). To gain insight into the cause(s) of the observed UV-enhanced toxicity of the IMs, comparative molecular responses to parent and UV-treated IMs were assessed using microarray-based global transcript expression assays. Both gene set enrichment analysis (GSEA) and differential transcript expression analysis coupled with pathway and annotation cluster enrichment were conducted to provide functional interpretations of expression results and hypothetical modes of toxicity. The parent NQ exposure caused significant enrichment of functions related to immune responses and proteasome-mediated protein metabolism occurring primarily at low, sublethal exposure levels (5.5 and 45.6mg/L). Enriched functions in the IMX-101 exposure were indicative of increased xenobiotic metabolism, oxidative stress mitigation, protein degradation, and anti-inflammatory responses, each of which displayed predominantly positive concentration-response relationships. UV-treated NQ had a fundamentally different transcriptomic expression profile relative to parent NQ causing positive concentration-response relationships for genes involved in oxidative-stress mitigation pathways and inhibited expression of multiple cadherins that facilitate zebrafish neurological and retinal development. Transcriptomic profiles were similar between UV-treated versus parent IMX-101 exposures. However, more significant and diverse enrichment as well as greater magnitudes of differential expression for oxidative stress responses were observed in UV-treated IMX-101 exposures. Further, transcriptomics indicated potential for cytokine signaling suppression providing potential connections between oxidative stress and anti-inflammatory responses. Given the overall results, we hypothesize that the increased toxicity of UV-irradiated NQ and the IMX-101 mixture result from breakdown products with elevated potential to elicit oxidative stress.