Modulating the Cellular Uptake of Fluorescently Tagged Substrates of Prostate-Specific Antigen before and after Enzymatic Activation.

A series of peptides based on the prostate-specific antigen (PSA)-specific sequence histidine-serine-serine-lysine-leucine-glutamine were functionalized with an anthraquinone fluorophore at the C-terminal residue side chain using the copper(I)-catalyzed azide-alkyne cycloaddition reaction. The effect of incorporating a negatively charged N-terminal tetra-glutamic acid group into the substrate and the effect of masking the negatively charged C-terminal carboxylic acid functionality of the substrate were investigated using confocal fluorescence microscopy in two cell lines, DLD-1 and LnCaP. The addition of a tetra-glutamic acid group to the N-terminus of the intact sequence was shown to reduce cellular uptake of the intact substrate prior to activation by PSA. In contrast, masking the C-terminal carboxylic acid group of the substrate as a methyl ester was shown to improve cellular uptake of the peptide fragment after activation by PSA. The synthesized C-terminal methyl ester substrates with the anthraquinone attached to the side chain were confirmed to be cleaved by PSA in LC-MS analysis, and the cytotoxicity of the substrates was shown to increase in the presence of PSA, consistent with cleavage and uptake of the C-terminal fragment. The results indicate that C- and N-terminal functionalization of peptide substrates targeting PSA can be used to modulate the cellular uptake of peptides before and after enzymatic activation, which may thus be an important consideration in the design of tumor-activated prodrugs.

Biodistribution and Clearance of Stable Superparamagnetic Maghemite Iron Oxide Nanoparticles in Mice Following Intraperitoneal Administration.

Nanomedicine is an emerging field with great potential in disease theranostics. We generated sterically stabilized superparamagnetic iron oxide nanoparticles (s-SPIONs) with average core diameters of 10 and 25 nm and determined the in vivo biodistribution and clearance profiles. Healthy nude mice underwent an intraperitoneal injection of these s-SPIONs at a dose of 90 mg Fe/kg body weight. Tissue iron biodistribution was monitored by atomic absorption spectroscopy and Prussian blue staining. Histopathological examination was performed to assess tissue toxicity. The 10 nm s-SPIONs resulted in higher tissue-iron levels, whereas the 25 nm s-SPIONs peaked earlier and cleared faster. Increased iron levels were detected in all organs and body fluids tested except for the brain, with notable increases in the liver, spleen, and the omentum. The tissue-iron returned to control or near control levels within 7 days post-injection, except in the omentum, which had the largest and most variable accumulation of s-SPIONs. No obvious tissue changes were noted although an influx of macrophages was observed in several tissues suggesting their involvement in s-SPION sequestration and clearance. These results demonstrate that the s-SPIONs do not degrade or aggregate in vivo and intraperitoneal administration is well tolerated, with a broad and transient biodistribution. In an ovarian tumor model, s-SPIONs were shown to accumulate in the tumors, highlighting their potential use as a chemotherapy delivery agent.

Open burning and open detonation PM10 mass emission factor measurements with optical remote sensing.

Emission factors (EFs) of particulate matter with aerodynamic diameter <10 microm (PM10) from the open burning/open detonation (OB/OD) of energetic materials were measured using a hybrid-optical remote sensing (hybrid-ORS) method. This method is based on the measurement of range-resolved PM backscattering values with a micropulse light detection and ranging (LIDAR; MPL) device. Field measurements were completed during March 2010 at Tooele Army Depot, Utah, which is an arid continental site. PM10 EFs were quantified for OB of M1 propellant and OD of 2,4,6-trinitrotoluene (TNT). EFs from this study are compared with previous OB/OD measurements reported in the literature that have been determined with point measurements either in enclosed or ambient environments, and with concurrent airborne point measurements. PM10 mass EFs, determined with the hybrid-ORS method, were 7.8 x 10(-3) kg PM10/kg M1 from OB of M1 propellant, and 0.20 kg PM10/kg TNT from OD of TNT. Compared with previous results reported in the literature, the hybrid-ORS method EFs were 13% larger for OB and 174% larger for OD. Compared with the concurrent airborne measurements, EF values from the hybrid-ORS method were 37% larger for OB and 54% larger for OD. For TNT, no statistically significant differences were observed for the EFs measured during the detonation of 22.7 and 45.4 kg of TNT, supporting that the total amount of detonated mass in this mass range does not have an effect on the EFs for OD of TNT.

Simultaneous removal of perchlorate and energetic compounds in munitions wastewater by zero-valent iron and perchlorate-respiring bacteria.

Ammonium perchlorate is one of the main constituents in Army's insensitive melt-pour explosive, PAX-21 in addition to RDX and 2,4-dinitroanisole (DNAN). The objective of this study is to develop an innovative treatment process to remove both perchlorate and energetic compounds simultaneously from PAX-21 production wastewater. It was hypothesized that the pretreatment of PAX-21 wastewater with zero-valent iron (ZVI) would convert energetic compounds to products that are more amenable for biological oxidation and that these products serve as electron donors for perchlorate-reducing bacteria. Results of batch ZVI reduction experiments showed that DNAN was completely reduced to 2,4-diaminoanisole and RDX was completely reduced to formaldehyde. Anaerobic batch biodegradation experiments showed that perchlorate (30 mg L(-1)) in ZVI-treated PAX-21 wastewater was decreased to an undetectable level after 5 days. Batch biodegradation experiments also confirmed that formaldehyde in ZVI-treated wastewater was the primary electron donor for perchlorate-respiring bacteria. The integrated iron-anaerobic bioreactor system was effective in completely removing energetic compounds and perchlorate from the PAX-21 wastewater without adding an exogenous electron donor. This study demonstrated that ZVI pretreatment not only removed energetic compounds, but also transformed energetic compounds to products that can serve as the source of electrons for perchlorate-respiring bacteria.

Optical remote sensing to quantify fugitive particulate mass emissions from stationary short-term and mobile continuous sources: part I. Method and examples.

The emissions of particulate matter (PM) from anthropogenic sources raise public concern. A new method is described here that was developed to complete in situ rapid response measurements of PM mass emissions from fugitive dust sources by use of optical remote sensing (ORS) and an anemometer. The ORS system consists of one ground-based micropulse light detection and ranging (MPL) device that was mounted on a positioner, two open path-Fourier transform infrared (OP-FTIR) spectrometers, and two open path-laser transmissometers (OP-LT). An algorithm was formulated to compute PM light extinction profiles along each of the plume's cross sections that were determined with the MPL. Size-specific PM mass emission factors were then calculated by integrating the light extinction profiles with particle mass extinction efficiencies (determined with the OP-FTIRs/OP-LTs) and the wind's speed and direction. This method also quantifies the spatial and temporal variability of the plume's PM mass concentrations across each of the plume's cross sections. Example results from three field studies are also described to demonstrate how this new method is used to determine mass emission factors as well as characterize the dust plumes' horizontal and vertical dimensions and temporal variability of the PM's mass concentration.

Optical remote sensing to quantify fugitive particulate mass emissions from stationary short-term and mobile continuous sources: part II. Field applications.

Quantification of emissions of fugitive particulate matter (PM) into the atmosphere from military training operations is of interest by the United States Department of Defense. A new range-resolved optical remote sensing (ORS) method was developed to quantify fugitive PM emissions from puff sources (i.e., artillery back blasts), ground-level mobile sources (i.e., movement of tracked vehicles), and elevated mobile sources (i.e., airborne helicopters) in desert areas that are prone to generating fugitive dust plumes. Real-time, in situ mass concentration profiles for PM mass with particle diameters <10 µm (PM(10)) and <2.5 µm (PM(2.5)) were obtained across the dust plumes that were generated by these activities with this new method. Back blasts caused during artillery firing were characterized as a stationary short-term puff source whose plumes typically dispersed to <10 m above the ground with durations of 10-30 s. Fugitive PM emissions caused by artillery back blasts were related to the zone charge and ranged from 51 to 463 g PM/firing for PM(10) and 9 to 176 g PM/firing for PM(2.5). Movement of tracked vehicles and flying helicopters was characterized as mobile continuous sources whose plumes typically dispersed 30-50 m above the ground with durations of 100-200 s. Fugitive PM emissions caused by moving tracked vehicles ranged from 8.3 to 72.5 kg PM/km for PM(10) and 1.1 to 17.2 kg PM/km for PM(2.5), and there was no obvious correlation between PM emission and vehicle speed. The emission factor for the helicopter flying at 3 m above the ground ranged from 14.5 to 114.1 kg PM/km for PM(10) and 5.0 to 39.5 kg PM/km for PM(2.5), depending on the velocity of the helicopter and type of soil it flies over. Fugitive PM emissions by an airborne helicopter were correlated with helicopter speed for a particular soil type. The results from this range-resolved ORS method were also compared with the data obtained with another path-integrated ORS method and a Flux Tower method.

Effect of gas empty bed contact time on performances of various types of rotating drum biofilters for removal of VOCs.

The effects of gas empty bed contact time (EBCT), biofilter configuration, and types of volatile organic compounds (VOCs) were evaluated to assess the performance of rotating drum biofilters (RDBs), especially at low EBCT values. Three types of pilot-scale RDBs, a single-layer RDB, a multi-layer RDB, and a hybrid RDB, were examined at various gas EBCTs but at a constant VOC loading rate. Diethyl ether, toluene, and hexane were used separately as model VOC. When EBCT increased from 5.0 to 60s at a constant VOC loading rate of 2.0kgCOD/(m(3)day), ether removal efficiency increased from 73.1% to 97.6%, from 81.6% to 99.9%, and from 84.0% to 99.9% for the single-layer RDB, the multi-layer RDB, and the hybrid RDB, respectively, and toluene removal efficiency increased from 76.4% to 99.9% and from 84.8% to 99.9% for the multi-layer RDB and the hybrid RDB, respectively. When hexane was used as the model VOC at a constant loading rate of 0.25kgCOD/(m(3)day), hexane removal efficiency increased from 31.1% to 57.0% and from 29.5% to 50.0% for the multi-layer RDB and hybrid RDB, respectively. The single-layer, multi-layer, and hybrid RDBs exhibited, respectively, the lowest, middle, and highest removal efficiencies, when operated under similar operational loading conditions. Hexane exhibited the lowest removal efficiency, while diethyl ether displayed the highest removal efficiency. The data collected at the various EBCT values correlated reasonably well with a saturation model. The sensitivity of removal efficiency to EBCT varied significantly with EBCT values, VOC properties, and biofilter configurations. Process selection and design for RDB processes should consider these factors.

Effect of carrier size on the performance of a three-phase circulating-bed biofilm reactor for removing toluene in gas stream.

A series of steady-state and short-term experiments on a three-phase circulating-bed biofilm reactor (CBBR) for removing toluene from gas streams were conducted to investigate the effect of macroporous-carrier size (1-mm cubes versus 4-mm cubes, which have the same total surface area) on CBBR performance. Experimental conditions were identical, except for the carrier size. The CBBR with 1-mm carriers (the 1-mm CBBR) overcame the performance limitation observed with the CBBR with 4-mm carriers (the 4-mm CBBR): oxygen depletion inside the biofilm. The 1-mm CBBR consistently had the superior removal efficiencies of toluene and COD, higher than 93% for all, and the advantage was greatest for the highest toluene loading, 0.12 M/m2-day. The 1-mm carriers achieved superior performance by minimizing the negative effects of oxygen depletion, because they had 4.7 to 6.8 times thinner biofilm depths. The 1-mm carriers continued to provide protection from excess biomass detachment and inhibition from toluene. Finally, the 1-mm CBBR achieved volumetric removal capacities up to 300 times greater than demonstrated by other biofilters treating toluene and related volatile hydrocarbons.

Field evaluation of digital optical method to quantify the visual opacity of plumes.

Visual Determination of the Opacity of Emissions from Stationary Sources (Method 9) is a reference method established by U.S. Environmental Protection Agency (EPA) to quantify plume opacity. However, Method 9 relies on observations from humans, which introduces subjectivity. In addition, it is expensive to teach and certify personnel to evaluate plume opacity on a semiannual basis. In this study, field tests were completed during a "smoke school" and a 4-month monitoring program of plumes emitted from stationary sources with a Method 9 qualified observer to evaluate the use of digital photography and two computer algorithms as an alternative to Method 9. This Digital Optical Method (DOM) improves objectivity, costs less to implement than Method 9, and provides archival photographic records of the plumes. Results from "smoke school" tests indicate that DOM passed six of eight tests when the sun was located in the 140 degrees sector behind one of the three cameras, with the individual opacity errors of 15% or less and average opacity errors of 7.5% or less. DOM also passed seven of the eight tests when the sun was located in the 216 degrees sector behind another camera. However, DOM passed only one of the eight tests when the sun was located in the 116 degrees sector in front of the third camera. Certification to read plume opacity by a "smoke reader" for 6 months requires that the "smoke reader" pass one of the smoke school tests during smoke school. The average opacity errors and percentage of observations with individual opacity errors above 15% for the results obtained with DOM were lower than those obtained by the smoke school trainees with the sun was located behind the camera, whereas they were higher than the smoke school trainee results with the sun located in front of the camera. In addition, the difference between plume opacity values obtained by DOM and a Method 9 qualified observer, as measured in the field for two industrial sources, were 2.2%. These encouraging results demonstrate that DOM is able to meet Method 9 requirements under a wide variety of field conditions and, therefore, has potential to be used as an alternative to Method 9.

Tunable and noncytotoxic PET/SPECT-MRI multimodality imaging probes using colloidally stable ligand-free superparamagnetic iron oxide nanoparticles.

Physiologically stable multimodality imaging probes for positron emission tomography/single-photon emission computed tomography (PET/SPECT)-magnetic resonance imaging (MRI) were synthesized using the superparamagnetic maghemite iron oxide (γ-Fe2O3) nanoparticles (SPIONs). The SPIONs were sterically stabilized with a finely tuned mixture of diblock copolymers with either methoxypolyethylene glycol (MPEG) or primary amine NH2 end groups. The radioisotope for PET or SPECT imaging was incorporated with the SPIONs at high temperature. 57Co2+ ions with a long half-life of 270.9 days were used as a model for the radiotracer to study the kinetics of radiolabeling, characterization, and the stability of the radiolabeled SPIONs. Radioactive 67Ga3+ and Cu2+-labeled SPIONs were also produced successfully using the optimized conditions from the 57Co2+-labeling process. No free radioisotopes were detected in the aqueous phase for the radiolabeled SPIONs 1 week after dispersion in phosphate-buffered saline (PBS). All labeled SPIONs were not only well dispersed and stable under physiological conditions but also noncytotoxic in vitro. The ability to design and produce physiologically stable radiolabeled magnetic nanoparticles with a finely controlled number of functionalizable end groups on the SPIONs enables the generation of a desirable and biologically compatible multimodality PET/SPECT-MRI agent on a single T2 contrast MRI probe.

Microbial reduction of perchlorate with zero-valent iron.

Microbial reduction of perchlorate in the presence of zero-valent iron was examined in both batch and column reactors to assess the potential of iron as the electron donor for biological perchlorate reduction process. Iron-supported mixed cultures completely removed 65 mg/L of perchlorate in batch reactors in 8 days. The removal rate was similar to that observed with hydrogen gas (5%) and acetate (173 mg/L) as electron donors. Repeated spiking of perchlorate to batch reactors containing iron granules and microorganisms showed that complete perchlorate reduction by the iron-supported culture was sustained over a long period. Complete removal of perchlorate by iron-supported anaerobic culture was also achieved in a bench-scale iron column with a hydraulic residence time of 2 days. This study demonstrated the potential applicability of zero-valent iron as a source of electrons for biological perchlorate reduction. Use of zero-valent iron may eliminate the need to continually supply electron donors such as organic substrates or explosive hydrogen gas. In addition, iron is inexpensive, safe to handle, and does not leave organic residuals in the treated water.

Enhanced reduction of perchlorate by elemental iron at elevated temperatures.

Kinetics of perchlorate reduction by elemental iron was examined at elevated temperatures using microwave heating and conventional block heating. It was hypothesized that increasing the solution temperature may accelerate the reduction of perchlorate by overcoming the high activation energy barrier. Results from microwave heating study showed that 98% of aqueous perchlorate was removed in 1 h at 200 degrees C. Similar results observed in control experiments with a block heater indicated that the enhancement in the extent and rate of perchlorate removal by elemental iron was mostly due to heat energy at high temperature. The rapid and complete reduction of perchlorate by elemental iron at elevated temperatures suggests that iron reduction process at elevated temperature may be an option to consider for complete removal of perchlorate from industrial discharges.

Zero-valent iron pretreatment for enhancing the biodegradability of RDX.

Hexahydro-1,3,5-trinitro-1,3,5-triazine (C3H6N3(NO2)3, royal demolition explosive or RDX) is a common nitramine explosive and one of the major constituents in wastewaters from ammunitions plants. The objective of this study is to investigate zero-valent iron (Fe0) pretreatment for enhancing the biodegradability of recalcitrant RDX. It was hypothesized that iron pretreatment can reductively transform RDX to products that are more amenable to biological treatment processes such as activated sludge. Results of batch and column experiments showed rapid and complete removal of RDX by Fe0 regardless of the buffering capacity. Formaldehyde (HCHO), a major reduction product of RDX, was readily biodegraded by a mixed culture. Respirometric data indicate that iron-treated RDX solution exerted substantially higher biochemical oxygen demand (BOD) than untreated RDX solution. We propose that an integrated iron reduction-activated sludge process may be a feasible option for treating RDX-laden wastewater.

Reductive transformation of hexahydro-1,3,5-trinitro-1,3,5-triazine, octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine, and methylenedinitramine with elemental iron.

Reductive (pre)treatment with elemental iron is a potentially useful method for degrading nitramine explosives in water and soil. In the present study, we examined the kinetics, products, and mechanisms of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) degradation with elemental iron. Both RDX and HMX were transformed with iron to formaldehyde, NH4+, N2O, and soluble products. The yields of formaldehyde were relatively constant (71% +/- 5%), whereas the yields of NH4+ and N2O varied, depending on the nitramine and the mechanism. The reactions most likely were controlled by a surface process rather than by external mass transfer. Methylenedinitramine (MDNA) was an intermediate of both RDX and HMX and was transformed quantitatively to formaldehyde with iron. However, product distributions and kinetic modeling results suggest that MDNA represented a minor reaction path and accounted for only 30% of the RDX reacted and 14% of the formaldehyde produced. Additional experiments showed that RDX reduction with elemental iron could be mediated by graphite and Fe2+ sorbed to magnetite, as demonstrated previously for nitroaromatics and nitrate esters. Methylenedinitramine was degraded primarily through reduction in the presence of elemental iron, because its hydrolysis was slow compared to its reactions with elemental iron and surface-bound Fe2+. Our results show that in a cast iron-water system, RDX may be transformed via multiple mechanisms involving different reaction paths and reaction sites.

Enhancing Fenton oxidation of TNT and RDX through pretreatment with zero-valent iron.

The effect of reductive treatment with elemental iron on the rate and extent of TOC removal by Fenton oxidation was studied for the explosives 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) using a completely stirred tank reactor (CSTR). The results support the hypothesis that TNT and RDX are reduced with elemental iron to products that are oxidized more rapidly and completely by Fenton's reagent. Iron pretreatment enhanced the extent of total organic carbon (TOC) removal by approximately 20% and 60% for TNT and RDX, respectively. Complete TOC removal was achieved for TNT and RDX solutions with iron pretreatment under optimal conditions. On the other hand, without iron pretreatment, complete TOC removal of TNT and RDX solutions was not achieved even with much higher H(2)O(2) and Fe(2+) concentrations. Nitrogen was recovered as NH(4)(+) and NO(3)(-) when Fe(0)-treated TNT and RDX solutions were subjected to Fenton oxidation. The bench-scale iron treatment-Fenton oxidation integrated system showed more than 95% TOC removal for TNT and RDX solutions under optimal conditions. These results suggest that the reduction products of TNT and RDX are more rapidly and completely degraded by Fenton oxidation and that a sequential iron treatment-Fenton oxidation process may be a viable technology for pink water treatment.

Effect of adsorption to elemental iron on the transformation of 2,4,6-trinitrotoluene and hexahydro-1,3,5-trinitro-1,3,5-triazine in solution.

The effect of adsorption to elemental iron on the reductive transformation of 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (royal demolition explosive [RDX]) in aqueous solution was studied with scrap iron and high-purity iron. In batch experiments with the same total iron surface area and a mixing rate of 100 rpm, TNT and RDX were removed from the solution within 30 min. With high-purity iron, adsorbed TNT was reduced to 2,4,6-triaminotoluene (TAT) rapidly, with little accumulation of intermediates at the surface. With scrap iron, the extent of adsorption of TNT and its daughter products was more significant and reduction of these adsorbed molecules to TAT was slower. Distribution of the intermediates indicated that the reaction with scrap iron occurred primarily through reduction of the ortho nitro group. Kinetic analysis suggests that mass transfer or adsorption of TNT controlled the overall rate of TNT reduction to TAT with pure iron, whereas with scrap iron, the rate of TAT formation was probably limited by other processes. Compared to TNT, transformation of adsorbed RDX was more rapid and less affected by iron type. The RDX was reduced to an unidentified, water-soluble intermediate and NH4+, which accounted for approximately 50% of the RDX nitrogen. No total organic carbon reduction was observed before and after RDX transformation with scrap iron.

Effect of substrate Henry's constant on biofilter performance.

Butanol, ether, toluene, and hexane, which have Henry's constants ranging from 0.0005 to 53, were used to investigate the effects of substrate solubility or availability on the removal of volatile organic compounds (VOCs) in trickle-bed biofilters. Results from this study suggest that, although removal of a VOC generally increases with a decrease in its Henry's constant, an optimal Henry's constant range for biofiltration may exist. For the treatment of VOCs with high Henry's constant values, such as hexane and toluene, the transfer of VOCs between the vapor and liquid phases or between the vapor phase and the biofilm is a rate-determining step. However, oxygen (O2) transfer may become a rate-limiting step in treating VOCs with low Henry's constants, such as butanol, especially at high organic loadings. The results demonstrated that in a gas-phase aerobic biofilter, nitrate can serve both as a growth-controlling nutrient and as an electron acceptor in a biofilm for the respiration of VOCs with low Henry's constants. Microbial communities within the biofilters were examined using denaturing gradient gel electrophoresis to provide a more complete picture of the effect of O2 limitation and denitrification on biofilter performance.

Effects of substrate and oxygen loading rates on gas-phase toluene removal in a three-phase biofilm reactor.

A three-phase, circulating-bed biofilm reactor using macroporous carriers removed toluene from a gas stream continuously for more than six months. Three steady states were established with toluene loading rates varying from 0.030 to 0.059 mol/m2 x d. For each steady state, short-term experiments evaluated the effects of toluene and oxygen loading rates. At least 99% of the biomass in the system was accumulated inside the carrier macropores, and the total biomass was proportional to the toluene loading rate. Toluene removal ranged from approximately 100 to 55%. The lower toluene removals were associated with oxygen limitation, which also resulted in the accumulation of an intermediate (3-methylcatechol) and nontoluene chemical oxygen demand. The results suggest that excessive biomass accumulation hurt process performance by depleting oxygen within the biofilm because increased endogenous respiration consumed more oxygen, while increased biomass density may have slowed oxygen diffusion.

Biotransformation of explosive-grade nitrocellulose under denitrifying and sulfidogenic conditions.

Waste nitrocellulose (NC) is regulated as a hazardous material. The objective of this study was to determine if NC exposed to denitrifying and sulfidogenic conditions would undergo sufficient removal of the nitro groups to yield a material that is no longer explosive. Enrichment cultures were established with methanol as the electron donor for nitrate-reducing conditions and lactate for sulfate-reducing conditions. NC was added to the cultures at 10 g/l. A statistically significant decrease in the nitrogen (N) content of NC occurred in both enrichment cultures, from approximately 13.1-13.2% in virgin NC to 12.2-12.4%. This was accompanied by an increase in nitrogen gas formation. The presence of a primary substrate (methanol and lactate) was necessary to affect this change; NC itself did not serve as an electron donor. In cultures that were carrying out denitrification but were then depleted of nitrate, with methanol still present, a slightly greater removal of nitro groups from NC occurred along with additional formation of nitrogen gas. NC did not have an inhibitory affect on the denitrification process but it did significantly slow the rate of lactate consumption and sulfate reduction. Fourier Transform Infrared Spectroscopy (FTIR) results indicated that NC exposed to denitrifying conditions was enriched in hydroxyl groups, consistent with removal of some of the nitro groups by hydrolysis of the nitrate esters. NC exposed to nitrate- and sulfate-reducing conditions and virgin NC were also compared based on their explosive properties using a small-scale burning test. The biologically treated NC exhibited somewhat less reactivity, but was still rated as explosive. The decrease in%N, increase in N2, and FTIR results demonstrated that NC does undergo biotransformation in the presence of nitrate- and sulfate-reducing enrichment cultures, but the extent of denitration does not appear to be adequate to yield a nonhazardous product.

The role of waixenicin A as transient receptor potential melastatin 7 blocker.

Transient receptor potential melastatin 7 (TRPM7) plays a role in a number of physiological and pharmacological functions in variety of cells. The aim of this study was to clarify the role for TRPM7 channels and the effect of waixenicin A on the pacemaking activity of interstitial cells of Cajal (ICCs) and on the cell viability of the human gastric and breast adenocarcinoma cell lines, AGS and MCF-7, respectively. Waixenicin A decreased the amplitude of pacemaker potentials in cultured ICC clusters and inhibited TRPM7 currents, but had no effect on Ca(2+) -activated Cl(-) conductance (ANO1). Furthermore, waixenicin A was found to inhibit the growth and survival of AGS and MCF-7 cells. These findings indicate that TRPM7 channel modulates intestinal motility and regulates the pathophysiology of human gastric and breast adenocarcinoma cells. These findings suggest that TRPM7 channel be considered a potential target for the treatment of gut motor disorders and gastric and breast cancer.