Abstract  A new approach for sensitive detection on a microfabricated chip is presented. Indirect laser-induced-fluorescence (IDLIF) was used to detect explosive compounds after separation by micellar electrokinetic chromatography (MEKC). The detection setup was used in an epifluorescence configuration with excitation provided by a near-IR diode laser operating at 750 nm. To achieve indirect detection, a low concentration of a dye (5 microM Cy7) was added to the running buffer as a visualizing agent. Using this methodology, a sample containing 14 explosives (EPA 8330 mixture) was examined. Concentrations of 1 ppm of trinitrobenzene (TNB), trinitrotoluene (TNT), dinitrobenzene (DNB), tetryl, and 2,4-dinitrotoluene (2,4-DNT) could be detected with S/N ratios between 3 and 10. Analyses showing 10 peaks, with plate numbers on the order of 60000, were completed within 60 s using a 65 mm long separation channel. The three isomers of nitrotoluene (2-, 3-, and 4-nitrotoluene) were not resolved. Additionally, the two nitramines (HMX and RDX) could only be detected at much higher concentrations, likely due to the low fluorescence quenching efficiencies of these compounds. The analysis method was also used to separate and detect nitroaromatic compounds in extracts from spiked soil samples. The presence of 1 ppm (1 microg of analyte/1 g of soil) of TNB, DNB, TNT, tetryl, 2,4-DNT, 2,6-DNT, 2-NH2-4,6-DNT, and 4-NH2-2,6-DNT could readily be detected. In the interest of increasing the sensitivity of the analysis, various on-chip injection schemes were evaluated. It was found that a 250 microm double-T injector gave a 35% increase in peak signal compared to a straight-cross injector, which is less than expected based on injected volume.

Abstract  Electrochemical reduction of trinitrotoluene (TNT) and several nitroaromatics has been exploited toward the development of an amperometric detector for liquid chromatography (LC). Up to a ten-fold increase in sensitivity was accomplished for the explosives using amperometric detection instead of conventional UV measurement. A working glassy carbon electrode (poised at -0.80 V vs. Ag/AgCl) offered a detection limit of 9, 44 and 550 nM for trinitrobenzene, TNT and 1,4-dinitrobenzene, respectively. Separation of eleven TNT-related compounds in a mixture was achieved within 15 min using a C18 column and a mobile phase consisting of acetonitrile-50 mM phosphate buffer pH 5 (1:2, v/v) and 18 mM sodium dodecylsulfate. The LC-amperometric detection system was applicable for analyzing soil extracts and ground water and the results obtained agreed well with that of the US Environmental Protection Agency recommended procedure. Extension to analysis of HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) and RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) was accomplished with a silver working electrode instead of a glassy carbon electrode installed in a thin channel cell.

Abstract  The eutectic temperature and composition were determined by thermal analysis for the systems: TNT–RDX, TNT–NENO, and DNB–NENO. The velocity of crystallization of pure RDX, as well as of the eutectic mixture of TNT–RDX, was studied. Density determinations were made on the pure materials, TNT, RDX, NENO, and DNB, as well as on the eutectic mixtures mentioned above. Where possible, the densities of both molten and solid forms were determined, and the contraction on solidification calculated. An attempt was made to establish the existence of a transition point in the allotropic transformations of NENO. The attempt failed, possibly because the allotropy is monotropic: there seems no reason to doubt the existence of allotropic modifications of NENO.

Abstract  Waste disposal practices associated with military production of weapons, especially before and during World War II, have resulted in significant contamination of soils and ground water with high explosives such as 2,4,6- trinitrotoluene (TNT), hexahydro-1,3,5- trinitro-1,3,5-triazine (RDX), and octahydro-1,3,5,7-tetranitro- 1,3,5,7-tetrazocine (HMX). Development of remediation and risk management strategies for these contaminated sites as well as development of approaches for sustainable use of active training and weapons testing sites require an understanding of how the energetic compounds interact with the environment Factors affecting fate and transport such as adsorption, microbial degradation, dissolution kinetics, solubility, and photolysis are determinants of ultimate environmental fate and exposure potential. This report summarizes the current understanding of these interactions, identifies significant data deficiencies, and provides updated process descriptors for primary explosives, transformation products, and impurities.

Abstract  Hyperthyroidism potentiates the in vivo hepatotoxicity of 1,1-dicholoroethylene (DCE) in rats, with a concomitant increase in [14C]-DCE covalent binding. The enhanced injury produced in hyperthyroid livers by DCE could be due to alterations in either the bioactivation or detoxication phases of DCE metabolism. Previous in vitro studies suggested that hyperthyroidism did not potentiate DCE hepatotoxicity by increasing DCE oxidation to intermediates which were able to covalently bind. Several factors, however, that could contribute to the magnitude of DCE bioactivation or covalent binding were not examined. Our objectives were to characterize the effects of hyperthyroidism in male Sprague-Dawley rats on: (1) covalent binding of [14C]-DCE to microsomes and other subcellular fractions, (2) microsomal mixed-function oxidase (MFO) and glutathione S-transferase (GST) activities, and (3) inactivation of microsomal enzyme activities by presumptive DCE reactive intermediates. Hyperthyroid (HYPERT) and euthyroid (EUT) rats received 3 s.c. injections of thyroxine (100 micrograms/100 g) or vehicle, respectively, at 48-h intervals; microsomes and other subcellular fractions were isolated from HYPERT and EUT livers 24 h after the last injection. [14C]-DCE-derived covalent binding was consistently greater in EUT than HYPERT microsomes. The absence of NADH, and the addition of low concentrations (0.1 and 0.5 mM), but not higher concentrations (> 1 mM), of glutathione (GSH) diminished covalent binding to a greater extent in HYPERT than EUT microsomes. Covalent binding in mitochondrial, nuclear, and cytosolic fractions of EUT and HYPERT livers was equivalent. Regression analysis of covalent binding to liver cell fractions from both EUT and HYPERT rats showed a significant correlation with P-450 content. Hyperthyroidism decreased microsomal, but not mitochondrial, cytochrome P-450 content, and MFO activities for 7-ethoxycoumarin and benzphermine were similarly decreased. Hyperthyroidism also diminished microsomal GST activity, and altered GST kinetics for both GSH and 1-chloro-2,4-dinitrobenzene (CDNB). The magnitude of inactivation of MFO and GST activities in the presence of DCE (presumably by DCE reactive intermediates) was comparable between EUT and HYPERT microsomes. When covalent binding was standardized to cytochrome P-450 concentrations in microsomes and mitochondria, HYPERT fractions exhibited slightly greater covalent binding than EUT fractions, suggesting that hyperthyroidism does not reduce the capacity of P-450 hemoproteins to bioactive DCE. Thus, potentiation of DCE hepatotoxicity by hyperthyroidism may be predominantly due to diminished Phase II constituents, and major increases in reactive intermediate/conjugates that covalently bind to and impair critical cellular molecules.

Abstract  Charge transfer complexes of substituted aryl Schiff bases as donors with picric acid and m-dinitrobenzene as acceptors were investigated by using computational analysis calculated by Configuration Interaction Singles Hartree-Fock (CIS-HF) at standard 6-31G∗ basis set and Time-Dependent Density-Functional Theory (TD-DFT) levels of theory at standard 6-31G∗∗ basis set, infrared spectra, visible and nuclear magnetic resonance spectra are investigated. The optimized geometries and vibrational frequencies were evaluated. The energy and oscillator strength were calculated by Configuration Interaction Singles Hartree-Fock method (CIS-HF) and the Time-Dependent Density-Functional Theory (TD-DFT) results. Electronic properties, such as HOMO and LUMO energies and band gaps of CTCs set, were studied by the Time-Dependent density functional theory with Becke-Lee-Young-Parr (B3LYP) composite exchange correlation functional and by Configuration Interaction Singles Hartree-Fock method (CIS-HF). The ionization potential Ip and electron affinity EA were calculated by PM3, HF and DFT methods. The columbic force was calculated theoretically by using (CIS-HF and TD-DFT) methods. This study confirms that the theoretical calculation of vibrational frequencies for (aryl Schiff bases--(m-dinitrobenzene and picric acid)) complexes are quite useful for the vibrational assignment and for predicting new vibrational frequencies.

Abstract  In this study, we utilized Mg-Al layered double hydroxide (Mg-Al LDH) modified by intercalation with three aromatic sulfonates-2,7-naphthalene disulfonate (2,7-NDS(2-)). benzenesulfonate (BS(-)), and benzenedisulfonate (BDS(2-))-for the uptake of two aromatics-1,3-dinitrobenzene (DNB) and anisole (AS)-from aqueous solution and determined the effect of the aromatic sulfonates on the uptake of these aromatics. We found that the electron-rich aromatic ring of the intercalated aromatic sulfonates such as 2,7-NDS(2-) undergoes strong pi-pi stacking interactions with the electron-poorer benzene ring of DNB in aqueous solution, and these interactions result in a higher uptake of DNB by the modified Mg-Al LDHs In contrast, the electron-poor aromatic ring of the aromatic sulfonates such as BDS(2-) undergoes weak pi-pi stacking interactions with the election-poorer benzene ring of DNB, and these interactions result in a lower uptake of DNB by the modified Mg-Al LDHs (C) 2010 Elsevier Ltd All rights reserved

Abstract  We have investigated the resistance of erythrocytes from diabetics and non-diabetics to glutathione depletion caused by p-benzoquinone, 1-chloro-2,4-dinitrobenzene (CDNB), diethyl maleate and 4-aminophenol. Incubation of erythrocytes with 4-aminophenol (2 mM) caused a precipitous reduction (>80%) in cellular glutathione levels although there was no significant difference between 4-aminophenol-mediated glutathione depletion in the diabetic and non-diabetic cells. p-Benzoquinone and CDNB were both associated with a less severe initial reduction in glutathione levels (>50% at 30 min) although p-benzoquinone caused greater depletion (P < 0.001) at 4.5 h (21.1 +/- 3.1%, non-diabetic; 20.0 +/- 1.0%, diabetic) compared with CDNB (49.2 +/- 2.2%, non-diabetic; 51.3 +/- 1.1% diabetic). Although there was no significant difference between the two types of cell in terms of level of depletion, administration of diethyl maleate caused a significant reduction in glutathione levels at 30 min (P < 0.0005), 3.5 h (P < 0.05) and 4.5 h (P < 0.05) in erythrocytes from diabetic man compared with those from non-diabetic man. Co-administration of buthionine sulphoximine (20 mM) and 4-aminophenol (1 mM) also led to a significant reduction in glutathione levels in diabetic cells at 30 min (P < 0.05), 3.5 h (P < 0.02) and 4.5 h (P < 0.007) compared with those in non-diabetic cells. The observations that diabetic red cells' resistance to depletion was similar to that of nondiabetic cells for three of the four depletors, and that the combination of 4-aminophenol and buthionine sulphoximine-mediated inhibition of glutathione synthesis was required to illustrate differences suggests that diabetic complications might be a result of the long-term effect of small deficiencies in oxidative self-defence mechanisms such as glutathione.

Abstract  The effects of the antioxidant lipoic acid and its reduced form, dihydrolipoic acid (DHLA), were studied on the process of the erythrocytic toxicity of 4-aminophenol in human erythrocytes in vitro. 4-Aminophenol alone caused a stepwise increase in methaemoglobin formation, along with a commensurate decrease in total thiols. At 10 min., in the presence of lipoic acid alone and the thiol depletor 1-chloro-2,4-dinitrobenzene (CDNB) alone, 4-aminophenol-mediated methaemoglobin formation was significantly increased, whilst thiol levels were significantly reduced compared with the 4-aminophenol alone. At 10 min., with DHLA and CDNB alone, 4-aminophenol was associated with significantly increased methaemoglobin formation. However, thiol levels were not significantly different in the presence of DHLA compared with 4-aminophenol alone, although thiol levels were different compared with control (4-aminophenol alone) in the incubations with CDNB alone. At 15 min., only CDNB/4-aminophenol methaemoglobin formation differed from control, whilst thiol levels were significantly lower in the presence of CDNB alone compared with 4-aminophenol alone. Lipoic acid enhanced the toxicity of 4-aminophenol in terms of increased methaemoglobin formation coupled with increased thiol depletion, whilst DHLA showed increased 4-aminophenol-mediated methaemoglobin formation without thiol depletion. Lipoic acid, and to a lesser extent its reduced derivative DHLA, acted as a prooxidant in the presence of 4-aminophenol, enhancing the oxidative stress effects of the amine in human erythrocytes.

Abstract  BIOSIS COPYRIGHT: BIOL ABS. RRM ANTINEOPLASTIC-DRUG DINITROCHLOROBENZENE CARCINOGEN

Abstract  The in vitro interaction of acetic acid and its chlorinated derivatives with rat liver glutathione S-transferases (GST) was studied, using glutathione (GSH) and 1-chloro-2,4-dinitrobenzene (CDNB) as substrates. The investigated compounds inhibited the GST activity in crude extracts in a dose dependent manner. Each of the different GST isoenzymes was inhibited by each of the compounds under study, albeit at very different degrees. Kinetic studies never revealed competitive inhibition kinetics, with GSH nor CDNB as the variable substrate. Titration of remaining GSH in appropriate incubation mixtures revealed no GST catalyzed conjugation with GSH. It is concluded that acetic acid and its chlorinated derivatives interact with GST by direct binding to these proteins. This binding could have a protective function against these compounds.

Abstract  Nickel is used in coins because the metal has beneficial properties, including price, colour, weight, and corrosion resistance, and also because it is easy to stamp. It has often been claimed that the duration of skin contact with coins is too short to cause nickel release and dermatitis. However, it is well known by dermatologists specialized in occupational skin diseases, and by their nickel-allergic patients, that hand eczema in cashiers and other professionals who handle coins may be caused or aggravated by nickel release from coins. In this review, we present evidence from past studies showing that nickel-containing coins can indeed pose a risk for those who handle them. For protection of the health of consumers, cashiers, and other workers who handle coins, it is suggested that coins without nickel release should be used as a substitute for the high nickel-releasing coins currently in widespread use. The key risk factor in this situation is the ability of metal alloys in coins to release nickel and contaminate the skin after repeated contact from coin handling.

Abstract  Liver, kidney, gill and olfactory epithelium cytosolic fractions of rainbow trout (Oncorhynchus mykiss) were examined for glutathione S-transferase (GST) contents. Proteins retained on a glutathione (GSH)-affinity matrix were separated as monomers by reversed-phase HPLC and characterized by immunoblotting, mass spectrometry and partial amino acid sequence. For each organ concerned, a specific pattern of these proteins was determined and appeared similar for liver and kidney on one hand, and for gill and olfactory epithelium on the other hand. It was confirmed that the prominent hepatic GST is a class pi enzyme, also constitutively expressed as a major isoform in the four organs studied. Moreover, a class pi variant and two new class mu GST subunits were characterized in minor fractions. An unknown protein, which was found major in gills and olfactory epithelium, exhibited some characteristics of class theta GSTs. Occurrence of possible GSH-adduct formation observed on two distinct monomers in specific experimental conditions is discussed. These results and methods were used to investigate the effect of 3,3',4,4'-tetrachlorobiphenyl (TCB), a polychlorinated biphenyl (PCB), on GST expression in trout liver. From HPLC-profiling, significant co-induction of the major class pi and the two minor class mu GST subunits was observed in trout after waterborne exposure to TCB which was followed by a slight increase in 1-chloro-2,4-dinitrobenzene (CDNB) activity. The present work allows qualitative evaluation of the specific detoxification potential of rainbow trout. The use of HPLC-profiling of GSTs as a possible tool for the biomonitoring of polluted aquatic environment is suggested.

Abstract  This report describes the improved quantitative determination of valiolamine in a medium for microbial culture using high-performance liquid chromatography with UV detection. Valiolamine aqueous solution was dried, dissolved in dimethyl sulfoxide and derivatization performances of phenylisocyanate (PHI), 1-fluoro-2,4-dinitrobenznene and 1-naphthylisothiocyanate were compared in the presence of triethylamine. The PHI was chosen as the most suitable derivatization reagent and the valiolamine-PHI derivative was identified by thin-layer chromatography and electrospray ionization mass spectrometry. The derivative eluted at 10.5 min on a reverse-phase column using a mobile phase composed of 10% acetonitrile in water containing 0.5 mM sodium octyl sulfate (pH 3.0), at a column flow rate of 1.0 mL/min with UV detection at 240 nm. The optimum conditions for derivatization were a reaction temperature of 30 degrees C, reaction time of 30 min, and PHI concentration higher than 33.6 mM. Calibration curves were linear in the range of 0.99-19.95 microg/mL for the standard solutions and 24.9-99.7 microg/mL for the spiked sample. The proposed method was validated and proven to be selective, accurate and precise and suitable for the quantitative analysis of valiolamine in medium for microbial cultures.

Abstract  After administration of beta-naphthoflavone and Clophen A50 to juvenile rainbow trout, activities of hepatic cytochrome P-450-dependent deethylation of 7-ethoxyresorufin was increased 172- and 49-fold, respectively. Glutathione transferase activity towards 1-chloro 2,4 dinitrobenzene and UDP glucuronosyltransferase activities towards p-nitrophenol, 1-naphthol and testosterone were increased 1.4 to 3.0-fold by beta-naphthoflavone or Clophen A50. However, significant increases of the rate of glucuronidation of 1-naphthol by Clophen A50 and of testosterone by both Clophen A50 and beta-naphthoflavone were only determined when the activities were measured in digitonin activated microsomes. Epoxide hydrolase activity was not affected by beta-naphthoflavone or Clophen A50. The time course of induction of the various xenobiotic metabolizing enzymes exhibited different patterns. 7-Ethoxyresorufin-O-deethylase activity reached peak values 3 and 7 days after the administration of beta-naphthoflavone and Clophen A50, respectively. The rate of induction of glutathione transferase activity and UDP glucuronosyltransferase activities towards p-nitrophenol and 1-naphthol were relatively slow and did not reach distinct peak levels. These activities were still on maximum levels 4-6 weeks after the treatment. Glucuronidation of testosterone reached peak values 1 week after treatment with both beta-naphthoflavone and Clophen A50. The dissimilar patterns of induction of the cytochrome P-450-dependent activities and the various conjugation activities may indicate that these xenobiotic metabolizing enzymes are differently regulated in the rainbow trout liver.

Abstract  In an effort to establish a single, rapid screening procedure for the sensitization and irritancy potential of new chemicals the parameters of a murine Local Lymph Node Assay and a mouse ear swelling irritancy assay were combined. To validate this assay, a range of chemical irritants and sensitizers were evaluated for their ability to elicit responses in B6C3F1 female mice. Chemicals were administered for four consecutive days to the dorsal and ventral surfaces of each ear An increase in ear thickness served to predict irritancy, while [H-3]thymidine uptake by cervical draining lymph nodes suggested sensitization. All chemicals known to be potent chemical sensitizers (oxazolone, 2,4-dinitrofluorobenzene, toluene diisocyanate) produced a marked lymph node cell proliferation in this assay. Animals exposed to irritating agents (sodium lauryl sulfate, croton oil, tetradecane, nonanoic acid, and benzalkonium chloride) experienced a significant increase in ear swelling. In addition, these irritating agents elicited Low-level lymphocyte proliferation. In cases where chemicals are considered to be both potent sensitizers and irritants (2,4-dinitrofluorobenzene, toluene diisocyanate, and benzalkonium chloride), robust increases in [H-3]thymidine incorporation and ear swelling were demonstrated. Results were dose-responsive for all chemicals tested. The combined LLNA/ear swelling assay appears to be a reliable predictor of sensitization and irritancy potential, since it identified the activity of all eight chemicals tested. The advantages of this approach include a further reduction in the number of animals and time required to screen chemicals for both irritancy and/or sensitization potential. Although this assay does mot have the capacity to discriminate between nonspecific lymph node proliferation and weak sensitizing ability of strong irritants, the information gained by the irritation component of the assay provides additional information when evaluating the significance of low-level lymphocyte proliferation in the LLNA. With further validation this assay could be useful as a common screening tool in the research and development of new chemical products.

Abstract  [3H]thymidine is incorporated into DNA from epidermal and dermal slices of untreated dorsal skin at similar rates. Treatment of dorsal skin with dibutyltin (67 nmoles/sq cm) stimulated the incorporation of the nucleoside into DNA from both preparations (relative to zero time controls) but the greater increase incurred into DNA from epidermal slices. Single cutaneous applications of different applied doses of dibutyltin, tributyltin, and 1-chloro-2: 4-dinitrobenzene altered the incorporation of [3H]thymidine into DNA of epidermal slices from the treated skin in a complex manner. Doses which produced minimal damage (as assessed histologically) stimulated the incorporation above zero time controls while doses producing moderate damage inhibited at early times and stimulated later. Doses which produced marked damage, not surprisingly, resulted in a marked and prolonged inhibition of incorporation. The increased incorporation of [3H]thymidine does not correlate with the degree of cellular damage as presently assessed histologically but does indicate the sensitivity and thus potential usefulness of biochemical parameters since considerable stimulation of thymidine incorporation was observed at times when minimal morphological changes were observed.

Abstract  Morphine, codeine and thebaine formed charge transfer complexes with acceptors like hydroquinone, benzoquinone, naphthaquinone, picric acid, chloranil and dinitrobenzene as evidenced from the shifting of absorption maxima and change in optical densities in the UV regions. The evidence of complex formation was observed from the optical densities of the complex in the visible region when D>>A and where D and A do not absorb. The evidence of complex formation was also adduced from FT-IR measurements for morphine + naphthaquinone, codeine + naphthaquinone and thebaine + naphthaquinone complexes. The formations of CT complexes with those acceptors arc confirmed from the plots of hvCT against IDV (vertical ionization potential) of the drugs. From the values CT transition energies, the vertical ionization potentials (IDV) of morphine, codeine and thebaine were estimated to be 7.228 ± 0.396, 7.236 ± 0.399 and 7.233 ± 0.405 eV respectively. The almost equal values are due to structural similarities of the drugs. The degrees of overlap in the ground state of the complexes were also calculated. The association constants and thermodynamics of the complexes (e.g. ΔG0, ΔH0 and ΔS0) were determined spectrophotometrically from the o.d measurements at 298, 303, 306 and 310 K using D and A in stoichiometric ratios, a condition necessary for the accurate determination of the association constants. The complexes are fairly stable.

Abstract  The aim of this review is to emphasize solvent free or green synthesis, a most efficient utilization of starting materials to give maximum yield, and an alternative route to producing novel promising materials. In this regard the phase diagram study has shown applications in the determination of the precise composition of binary compounds of a specific nature and in the identification of the parameters that affect the crystal growth. To provide an overview worthy of phase diagram, physicochemical, thermal and structure investigations; studies of eleven systems, namely, urea–m-nitrobenzoic acid, urea–p-nitrophenol, urea–resorcinol, benzoin–o-phenylenediamine, pyrene–m-dinitrobenzene, vanillin–p-anisidine, resorcinol–p-dimethylaminobenzaldehyde, benzophenone–diphenylamine, anthracene–picric acid, 8-hydroxyquinoline–salicylic acid and 8-hydroxyqunoline–1,2,3-trihydroxybenzene forming organic complexes, have been reported. In addition, the original data of a newly synthesized complex of m-hydroxybenzaldehyde (HB) and p-chloroaniline (CA) is being reported for the first time. The phase diagram of HB–CA system also shows the formation of a complex in 1:1 M ratio, and two eutectics on either side of the complex. The complex's formation was studied using FTIR, NMR, DSC and powder X-ray diffraction techniques. The thermodynamic parameters such as heat of mixing, entropy of fusion, roughness parameter, interfacial energy and excess thermodynamic functions were calculated using the heat of fusion values. The single crystal growth and the atomic packing studies of some of the complexes have confirmed the formation of complexes. The optical transmittance efficiency and transparency of novel HB–CA complex crystal were found to be 70% and 399 nm, respectively. © 2013 Elsevier Ltd

Abstract  This paper describes the development and comparison of two immunoassays for the detection of 2,4,6-trinitrotoluene (TNT) based on competitive inhibition. Two polyclonal antibodies were used in the immunoassay; one was prepared from 2,4,6-trinitrophenol-bovine serum albumin conjugate (anti-TNP-BSA Ab, goat IgG) and another from 2,4,6-trinitrophenyl-keyhole limpet hemocyanine conjugate (anti-TNPh-KLH Ab, rabbit IgG). A solid-phase immunoassay that consisted of physically immobilized TNP-BSA conjugate was allowed to interact with these antibodies and the resonance angle changes due to the biomolecular interactions were monitored by surface plasmon resonance (SPR). The quantification of TNT was based on the change in the resonance angle shift for binding of antibodies with a TNP-BSA conjugate, which occurred in the presence of TNT in solution. Both antibodies showed a high degree of affinity for TNT and varying degrees of cross-reactivity to the related nitroaromatic derivative compounds, such as 2,4- dinitrotoluene (DNT), 1,3-dinitrobenzene (DNB), 2-amino-4,6-dintitrotoluene (2A- 4,6-DNT), 4-amino-2,6-dinitrotoluene (4A-2,6-DNT) and TNP. The anti-TNPh-KLH Ab prepared in our laboratory showed a detection limit of 0.006 ng/ml (6 ppt), which was comparable to or even better than the detection limit (0.095 ng/ml or 95 ppt) of a commercially available anti-TNP-BSA Ab for detection of TNT. A pepsin solution prepared with a glycine-HCl buffer (pH 2.0) was used for regeneration of the sensor surface. The duration for a single immunocycle was 19 and 13 min for anti-TNP-BSA Ab and anti-TNPh-KLH Ab immunosystems, respectively. The proposed immunoassay is simple and possesses good analytical characteristics for quantification of TNT.

Abstract  The blowing of carbon nanotubes (CNT) into carbon nanobulbs by employing a mixture of picric acid and nickel formate was discussed. It was shown that the CNT can be deformed into small fullerenes such as C60 of large multi-walled fullerene onions, through a fragmentation-reconstruction process. The blown spherical bulbs were characterized by large dimensions, thin walls and fully hollow cores. It was reported that multi-walled CNT can be efficiently obtained by explosive decomposition of picric acid or m-dinitrobenzene in the presence of a cobalt or nickle catalyst. It was shown that the products from the decomposition of the picric acid and nickle formated mixture contain large amounts of spherical bulbs along with multi-walled CNT.

Abstract  EPR analysis shows that the anion radical of 2,6-dinitrotoluene (DNT) in liquid ammonia exists with the counterion (either K(+) or Na(+)) associated with one of the two nitro groups. This tight association (-NO(2)(*-)M(+)) persists after solvent removal, and it renders the anion radical very susceptible to loss of metal nitrite. The slightest agitation of the solid potassium salt of DNT(*-) leads to detonation, and formation of KNO(2) and polymer (in the solid phase) and CH(4), HCN, H(2), and N(2)O (in the gas phase). Trapping experiments suggest that the methane comes from carbenes, and it is suggested that the HCN comes from an anthranil radical intermediate. The potassium anion radical salts of 1,3-dinitrobenzene, 2,6-dinitrotoluene, 1,3,5-trinitrobenzene, and 2,4,6-trinitrotoluene all readily lose KNO(2), and the ease of C-NO(2)(*-)M(+) bond rupture increases with the degree of nitration. In the cases of the two trinitrated systems dissociation takes place immediately upon anion radical formation in liquid ammonia. This observation is consistent with the fact that only the systems with two nitro groups vicinal to a methyl group yield HCN upon detonation.

Abstract  The primary explosive found in most land mines, 2,4,6-trinitrotoluene (2,4,6-TNT), is often accompanied by 2,4-dinitrotoluene (2,4-DNT) and 1,3-dinitrobenzene (1,3-DNB) impurities. The latter two compounds, being more volatile, have been reported to slowly leak through land mine covers and permeate the soil under which they are located, thus serving as potential indicators for buried land mines. We report on the construction of genetically engineered Escherichia coli bioreporter strains for the detection of these compounds, based on a genetic fusion between two gene promoters, yqjF and ybiJ, to either the green fluorescent protein gene GFPmut2 or to Photorhabdus luminescens bioluminescence luxCDABE genes. These two gene promoters were identified by exposing to 2,4-DNT a comprehensive library of about 2,000 E. coli reporter strains, each harboring a different E. coli gene promoter controlling a fluorescent protein reporter gene. Both reporter strains detected 2,4-DNT in an aqueous solution as well as in vapor form or when buried in soil. Performance of the yqjF-based sensor was significantly improved in terms of detection threshold, response time, and signal intensity, following two rounds of random mutagenesis in the promoter region. Both yqjF-based and ybiJ-based reporters were also induced by 2,4,6-TNT and 1,3-DNB. It was further demonstrated that both 2,4,6-TNT and 2,4-DNT are metabolized by E. coli and that the actual induction of both yqjF and ybiJ is caused by yet unidentified degradation products. This is the first demonstration of an E. coli whole-cell sensor strain for 2,4-DNT and 2,4,6-TNT, constructed using its own endogenous sensing elements.

Abstract  Benzyl isothiocyanate, beta-naphthoflavone, coumarin, alpha-angelicalactone, disulfiram, indole-3-carbinol and indole-3-acetonitrile induced increased glutathione (GSH) S-transferase activity in the liver and small intestine in female ICR/Ha mice. All seven compounds are inhibitors of chemical carcinogenesis. In additional work, several dietary constituents increased GSH S-transferase activity. Consumption of diets containing dried powdered preparations of brussels sprouts, cabbage, coffee beans, or tea leaves resulted in increased GSH S-transferase activity. Mice fed an unrefined diet (Purina Rat Chow) had a higher GSH S-transferase activity than those fed a semipurified diet. The results of the present study indicated that the composition of the diet can alter the activity of an important enzyme system having the capacity to detoxify chemical carcinogens.