Range Of Exposure Times Research Articles

Molecular characterization of DDT resistance in Anopheles gambiae from Benin.

BackgroundInsecticide resistance in the mosquito vector is the one of the main obstacles against effective malaria control. In order to implement insecticide resistance management strategies, it is important to understand the genetic factors involved. In this context, we investigated the molecular basis of DDT resistance in the main malaria vector from Benin.MethodsAnopheles gambiae mosquitoes were collected from four sites across Benin and identified to species/molecular form. Mosquitoes from Cotonou (M-form), Tori-Bossito (S-form) and Bohicon (S-form) were exposed to DDT 4% at a range of exposure times (30 min to 300 min). Another batch of mosquitoes from Cotonou and Malanville were exposed to DDT for 1 hour and the survivors 48 hours post exposure were used to quantify metabolic gene expression. Quantitative PCR assays were used to quantify mRNA levels of metabolic enzymes: GSTE2, GSTD3, CYP6P3 and CYP6M2. Expression (fold-change) was calculated using the ∆∆Ct method and compared to susceptible strains. Detection of target-site mutations (L1014F, L1014S and N1575Y) was performed using allelic discrimination TaqMan assays.ResultsDDT resistance was extremely high in all populations, regardless of molecular form, with no observed mortality after 300 min exposure. In both DDT-survivors and non-exposed mosquitoes, GSTE2 and GSTD3 were over-expressed in the M form at 4.4-fold and 3.5-fold in Cotonou and 1.5-fold and 2.5-fold in Malanville respectively, when compared to the susceptible strain. The CYP6M2 and CYP6P3 were over-expressed at 4.6-fold and 3.8-fold in Cotonou and 1.2-fold and 2.5-fold in Malanville respectively. In contrast, no differences in GSTE2 and CYP6M2 were observed between S form mosquitoes from Tori-Bossito and Bohicon compared to susceptible strain. The 1014 F allele was fixed in the S-form and at high frequency in the M-form (0.7-0.914). The frequency of 1575Y allele was 0.29-0.36 in the S-form and nil in the M-form. The 1014S allele was detected in the S form of An. gambiae in a 1014 F/1014S heterozygous specimen.ConclusionOur results show that the kdr 1014 F, 1014S and 1575Y alleles are widespread in Benin and the expression of two candidate metabolic markers (GSTE2 and CYP6M2) are over-expressed specifically in the M-form.

Effect of Aqueous Ozone on Alfatoxin Degradation in Pistachio of Ohadi Cultivar

In this research effectiveness of immersing three types of contaminated pistachios fresh with hull (exocarp or epicarp), dried in shell and dried with hull from Ohady cultivar in ozonated water 0 ppm (control), 4 and 8 ppm ozone concentrations in aqueous solution for range of exposure times 0(control), 2, 4, 6, 8, 10 and12 hours, to decrease of aflatoxin (B1, B2, G1, G2 and total) were investigated. Water temperature and pH were 10°C and 5.5± 0.3 respectively. For all samples, interaction between, ozone concentration and exposure times or pistachio type, were investigated. Aflatoxin (AF) B1 content was more and was reduced easily. Results showed that differences between the control samples (zero hour and/or 0ppm ozone) and treated pistachios for total aflatoxins and aflatoxin B1 were significant(P G2 & B2 respectively.

Expression of Heat Shock Protein and Antioxidant Genes in Rice Leaf Under Heat Stress

We have previously investigated the proteome changes of rice leaves under heat stress (Lee et al. in Proteomics 2007a, 7:3369- 3383), wherein a group of antioxidant proteins and heat shock proteins (HSPs) were found to be regulated differently. The present study focuses on the biochemical changes and gene expression profiles of heat shock protein and antioxidant genes in rice leaves in response to heat stress (42°C) during a wide range of exposure times. The results show that hydrogen peroxide and proline contents increased significantly, suggesting an oxidative burst and osmotic imbalance under heat stress. The mRNA levels of chaperone 60, HSP70, HSP100, chloroplastic HSP26, and mitochondrial small HSP responded rapidly and showed maximum expression after 0.5 or 2 h under heat stress. Transcript levels of ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR) and Cu-Zn superoxide dismutase (Cu-Zn SOD) showed a rapid and marked accumulation upon heat stress. While prolonged exposure to heat stress resulted in increased transcript levels of monodehydroascorbate reductase, peroxidase, glyoxalase 1, glutathione reductase, thioredoxin peroxidase, 2-Cysteine peroxiredoxin, and nucleoside diphosphate kinase 1, while the transcription of catalase was suppressed. Consistent with their changes in gene expression, the enzyme activities of APX and DHAR also increased significantly following exposure to heat stress. These results suggest that oxidative stress is usually caused by heat stress, and plants apply complex HSP- and antioxidant-mediated defense mechanisms to cope with heat stress.

Disinfection of Ballast Water with Iron Activated Persulfate

The treatment of ballast water carried onboard ships is critical to reduce the spread of nonindigenous aquatic organisms that potentially include noxious and harmful taxa. We tested the efficacy of persulfate (peroxydisulfate, S2O8(2-), PS) activated with zerovalent iron (Fe(0)) as a chemical biocide against two taxa of marine phytoplankton grown in bench-scale, batch cultures: the diatom, Pseudonitzshia delicatissima and the green alga, Dunaliella tertiolecta . After testing a range of PS concentrations (0-4 mM activated PS) and exposure times (1-7 days), we determined that a dosage of 4 mM of activated PS was required to inactivate cells from both species, as indicated by reduced or halted growth and a reduction in photosynthetic performance. Longer exposure times were required to fully inactivate D. tertiolecta (7 days) compared to P. delicatissima (5 days). Under these conditions, no recovery was observed upon placing cells from the exposed cultures into fresh media lacking biocide. The results demonstrate that activated PS is an effective chemical biocide against species of marine phytoplankton. The lack of harmful byproducts produced during application makes PS an attractive alternative to other biocides currently in use for ballast water treatments and merits further testing at a larger scale.

The effect of surface sterilants on spore germination of Fusarium oxysporum f. sp. cubense tropical race 4

Fusarium wilt of banana is a devastating disease caused by Fusarium oxysporum f. sp. cubense (Foc). The ‘tropical’ race 4 strain (Foc TR4) has a significant impact on the banana industry worldwide. To prevent this soilborne disease from spreading, the best practice is to minimise movement of infested soil. Investigations were made on three products, Farmcleanse®, Sporekill® and Domestos®, to determine their suitability as surface sterilants for use in footbaths and on machinery. Assessments involved analysing the rates of microconidia germination, following treatment with fresh preparations of each product, at a range of concentrations and exposure times; and also with preparations of each, after exposure to heat and sunlight, for a range of times. Sporekill® was a better surface sterilant than Farmcleanse® and Domestos®, preventing germination of microconidia after the minimum exposure time of 30 s. Sporekill® was also able to inhibit microconidia germination after 6 months of exposure to heat and sunlight. This study demonstrated that Sporekill® is more effective than Farmcleanse® in inhibiting the germination of Foc TR4 spores, and may be beneficial for use in footbaths and the general disinfestation of machinery contaminated with Foc TR4.

Influence of water vapor condensation on exhaust gas recirculation cooler fouling

Cooled exhaust gas recirculation (EGR) is widely used in diesel engines to control engine out NOx (oxides of nitrogen) emissions. A portion of the exhaust gases is re-circulated into the intake manifold of the engine after cooling it through a heat exchanger known as an EGR cooler. EGR cooler heat exchangers, however, tend to lose efficiency and have increased pressure drop as deposit forms on the heat exchanger surface due to transport of soot particles and condensing species to the cooler walls. The focus of this study was to investigate whether surface condensation of water vapor could be used to remove the accumulated deposit mass from various types of deposit layers typically encountered in EGR coolers. Both visual and quantitative evidence of water vapor condensation and deposit removal were collected. A multi-cylinder diesel engine was used to produce three different deposit layers in a custom built single rectangular channel EGR cooler. The deposit layers were then exposed to water vapor condensation over a range of coolant temperatures, flow rates and exposure times by adjusting the engine operating conditions. Significant flaking and removal of deposit layers made up of mostly soot particles was observed when exposed to condensation of water vapor even with an exposure duration as low as 5min. However, very little removal of deposit mass with exposure to water vapor condensation was observed when the deposit layer consisted of condensed exhaust hydrocarbon species in addition to soot. In addition to engine experiments a visualization test rig was setup to visualize condensation of water vapor from clean humid air and its effect on different deposit layers. Surface condensation of water vapor can lead to significant removal of certain deposit layers from the cooler walls and, thus, mitigate fouling of the EGR cooler. It could potentially be used as regeneration strategy for periodic on-board regeneration of fouled EGR coolers.

Improved fracture toughness of boride coating developed with a diffusion annealing process

In this study, the fracture toughness of boride coatings formed at the surface of AISI 1045 steel was improved by means of a diffusion annealing process. First, the boriding of AISI 1045 steel was performed by the powder-pack method at a temperature of 1223K and a range of exposure times (8–12h). The diffusion annealing process was conducted on the borided steels at a temperature of 1273K with 8h of exposure using a diluent atmosphere of SiC powder and bentonite. To establish the mechanical behavior of the boride coatings developed by both treatments, properties such as the real hardness and the Young's modulus were estimated at 50μm from the surface using Vickers and Knoop testing, respectively. The fracture toughness of the boride coatings was estimated using a universal crack equation applicable independently of the cracking mode. The boride coating obtained by the boriding process exhibited an intermediate cracking mode, while the coatings obtained by the diffusion annealing process showed a radial-median mode.The effect of the diffusion annealing process on the fracture toughness of the boride coatings revealed an increase of approximately 50% in comparison with the coatings developed by the powder-pack boriding process.

Mixed Phase Gratings: Contribution of Refractive Index Modulations to Diffraction Efficiency

The phase gratings have been recorded in silver halide emulsion (Slavich PFG-01) by utilizing a two-beam laser interferometric technique and Kodak DA-163 as a developer. Such gratings are observed to conform to both the surface relief and refractive index modulations. In the present work, we have studied the contribution of refractive index modulations to diffraction efficiency of the phase gratings for a broad range of exposure time (30-180 s) of recording. It has been observed that contribution of index modulation to diffraction efficiency of the gratings increases with increasing time of exposure in the range of 30-90 s and then saturates. Contribution of relief modulation to diffraction efficiency is also discussed.

Concentration Dependence of Vitamin C in Combinations with Vitamin E and Zeaxanthin on Light‐Induced Toxicity to Retinal Pigment Epithelial Cells

The purpose of this study was to determine the effects of increasing concentration of ascorbate alone and in combinations with α-tocopherol and zeaxanthin on phototoxicity to the retinal pigment epithelium. ARPE-19 cells were exposed to rose bengal and visible light in the presence and absence of antioxidants. Toxicity was quantified by an assay of cell-reductive activity. A 20min exposure to visible light and photosensitizer decreased cell viability to ca 42%. Lipophilic antioxidants increased viabilities to ca 70%, 61% and 75% for α-tocopherol, zeaxanthin and their combination, respectively. Cell viabilities were ca 70%, 56% and 5% after exposures in the presence of 0.35, 0.7 and 1.4mm ascorbate, respectively. A 45min exposure increased cell death to ca 74% and >95% in the absence and presence of ascorbate, respectively. In the presence of ascorbate, zeaxanthin did not significantly affect phototoxicity. α-Tocopherol and its combination with zeaxanthin enhanced protective effects of ascorbate, but did not prevent from ascorbate-mediated deleterious effects. In conclusion, there is a narrow range of concentrations and exposure times where ascorbate exerts photoprotective effects, exceeding which leads to ascorbate-mediated increase in photocytotoxicity. Vitamin E and its combination with zeaxanthin can enhance protective effects of ascorbate, but do not ameliorate its deleterious effects.

Radiation Exposure Time during MBSS: Influence of Swallowing Impairment Severity, Medical Diagnosis, Clinician Experience, and Standardized Protocol Use

Guidelines and preventive measures have been established to limit radiation exposure time during modified barium swallow studies (MBSS) but multiple variables may influence the duration of the exam. This study examined the influence of clinician experience, medical diagnosis category, swallowing impairment severity, and use of a standardized protocol on fluoroscopy time. A retrospective review of 739 MBSSs performed on 612 patients (342 males/270 females; age range = 18-96 years) completed in 1 year at the Medical University of South Carolina was performed with IRB approval. All studies were completed by speech-language pathologists trained in the data collection protocol, interpretation, and scoring of the MBSImP™(©). Medical diagnosis category, swallowing impairment severity (MBSImP™(©) score), clinician experience, and fluoroscopy time were the variables recorded for analysis. Fluoroscopy time was not significantly associated with medical diagnosis category (p = 0.10). The severity of the MBSImP™(©) Oral Total and Pharyngeal Total resulted in statistically significant increases in fluoroscopy time (p < 0.05). Studies by novice clinicians had longer exposure times when compared to those of experienced clinicians (p = 0.037). Average radiation exposure time using the MBSImP™(©) approach was 2.9 min, with a 95 % confidence interval of 2.8-3.0 min, which was well within the range of exposure times reported in the literature. This study provides preliminary information regarding the impact of medical diagnosis category, swallowing impairment severity, and clinician experience on fluoroscopy time. These findings also suggest that a thorough, standardized protocol for MBSSs did not cause unnecessary radiation exposure time during the MBSS.

Accelerated ageing behaviors of aluminum plate with composite patches under salt fog effect

The present study investigated the salt fog effect on the quasi-static tensile and fatigue properties of the center-cracked aluminum plates which were single-sidedly repaired with Cf/epoxy composite patches. The results show that the salt fog has minimal impact on the quasi-static tensile properties of the epoxy resin and Cf/epoxy composites; while the quasi-static tensile and fatigue properties of the repaired and unrepaired specimens all decrease with the exposure time of the salt fog increasing. Compared to the unrepaired specimens, the repaired specimens have high resistance to salt fog degradation. Within the 0–900h range of exposure time, the repaired specimens completely fail when the fatigue crack length is equal to the width of the aluminum plate. However, as the exposure time is larger than 900h, the repaired specimens can still bear fatigue loading when the fatigue crack propagates through the aluminum plate.

Comparing Photodamage Induced by Confocal Microscopy and Light Sheet Fluorescence Imaging of Zebrafish Skeletal Development

Understanding the formation of multicellular structures during embryogenesis requires high quality three dimensional microscopy over long periods of time, a task for which confocal fluorescence microscopy has become the standard technique. Extended viewing of developing structures in vivo, however, exposes the organism to prolonged illumination that runs the risk of being detrimental to the processes being studied. Furthermore, the effects of phototoxicity may not be apparent over the course of an experiment, as they may become significant well before any photobleaching of the sample is observed. Selective plane illumination microscopy (SPIM), or “¯light sheet” microscopy, has been developed as an imaging platform that can address the issues of phototoxicity, acquisition rate, and photon efficiency present in confocal methods of imaging. While it is known that SPIM requires orders of magnitude less light intensity than confocal techniques for similar imaging conditions, it has not been previously demonstrated that this difference is relevant to maintaining normal biological function. Using the development of the opercle, a cranio-facial structure in larval zebrafish (Danio rerio), we have tested the effects of long term imaging using a commercial spinning disk confocal microscope as compared to our own self-built SPIM instrument. Examining a range of exposure times and scan durations of several hours, we find that confocal imaging can generate significantly abnormal growth of bone forming cells (sp7:eGFP transgenic), especially if high signal to noise is desired. In contrast, we find normal opercle development with SPIM throughout the entire examined range of conditions.

Cytotoxic and Genotoxic Effects of the Quercetin/Lanthanum Complex on Human Cervical Carcinoma Cells In Vitro

Quercetin is the main flavonoid in diet with a potential in the treatment of cancer, cardiovascular, and neurodegenerative diseases. Due to its specific planar chemical structure, quercetin readily forms chelates with metal ions. Complexes of bioactive compounds and metal ions such as lanthanum often show strong cytotoxic and antitumour properties. The aim of this study was to compare the genotoxic effects of the quercetin/lanthanum complex on human cervical carcinoma cells with compare it to the effects of free ligands, quercetin, and lanthanum alone. The quercetin/lanthanum complex showed considerable cytotoxicity in the concentration range of (100 to 1000) mmol mL-1 and exposure time of three hours. The complex also induced a dose-dependent pro-oxidative effects and the formation of single-strand and double-strand DNA breaks. Although we obtained promising results on the cell level, future experiments should answer whether the quercetin/lanthanum complex is cancer-specific and stable enough in physiological conditions to make a potential new antitumour drug.

A simple algebraic model to predict burn depth and injury

A numerical model has been used to predict the depth of burns which result when human skin is exposed to high-temperature water. The model included a multi-layer facsimile of skin tissue (epidermal, dermal, subcutaneous fat, and muscle). The investigation covered a wide range of temperatures and exposure times. For lower temperatures and shorter exposure times, the model correctly predicts minimal burn injury while for higher temperatures and longer exposure durations, the burn extent is found to extend throughout the epidermal and dermal layers. Based on the results from the simulations, a simple approximating function was developed that allows medical practitioners to quickly and accurately determine the depth of injury. This tool will improve prognosis and enable more appropriate care to be delivered to patients. The approximating function was compared with data from the literature and was found to be in good agreement.

A method to correct for stray light in telecentric optical-CT imaging of radiochromic dosimeters

Radiochromic plastic and gel materials have recently emerged which can yield 3D dose information over clinical volumes in high resolution. These dosimeters can provide a much more comprehensive verification of complex radiation therapy treatments than can be achieved by conventional planar and point dosimeters. To achieve full clinical potential, these dosimeters require a fast and accurate read-out technology. Broad-beam optical-computed tomography (optical-CT) systems have shown promise, but can be sensitive to stray light artifacts originating in the imaging chain. In this work we present and evaluate a method to correct for stray light artifacts by deconvolving a measured, spatially invariant, point spread function (PSF). The correction was developed for the DLOS (Duke large field-of-view optical-CT scanner) in conjunction with radiochromic PRESAGE® dosimeters. The PSF was constructed from a series of acquisitions of projection images of various sized apertures placed in the optical imaging chain. Images were acquired with a range of exposure times, and for a range of aperture sizes (0.2–11 mm). The PSF is investigated under a variety of conditions, and found to be robust and spatially invariant, key factors enabling the viability of the deconvolution approach. The spatial invariance and robustness of the PSF are facilitated by telecentric imaging, which produces a collimated light beam and removes stray light originating upstream of the imaging lens. The telecentric capability of the DLOS therefore represents a significant advantage, both in keeping stray light levels to a minimum and enabling viability of an accurate PSF deconvolution method to correct for the residual. The performance of the correction method was evaluated on projection images containing known optical-density variations, and also on known 3D dose distributions. The method is shown to accurately account for stray light on small field dosimetry with corrections up to 3% in magnitude shown here although corrections of >10% have been observed in extreme cases. The dominant source of stray light was found to be within the imaging lens. Correcting for stray light extended the dynamic range of the system from ∼30 to ∼60 dB. The correction should be used when measurements need to be accurate within 3%.

Phase contrast neutron imaging at the PULSTAR reactor

Abstract Non-interferometric phase contrast effects have been shown to enhance material edges in neutron images. The achieved contrast enhancement in the image depends upon the neutron coherent scattering lengths of the materials present in the object and the degree of spatial coherence of the neutron beam. Spatial coherence of the beam is achieved using design-based spatial filters, a large L / d ratio (∼10,000) and low average neutron energy. Physically, a large L / d ratio is realized by a pinhole neutron source thereby significantly reducing the neutron beam intensity at the image plane. Thus, performance of such imaging exercises at low/medium intensity neutron sources is associated with additional design considerations that are not needed at high intensity neutron sources, where it has been demonstrated. In the present work, phase contrast neutron imaging was conducted using a suitably designed collimator at the 1-MWth PULSTAR reactor located at North Carolina State University (NCSU). Results of the imaging exercises that depict phase contrast edge enhancement are being presented along with the collimator design. Digital image plate detectors were used to capture images with a range of exposure times between 45 and 120 min.

Hello?…Hello? Is anyone out there?

(Or Shallow Water: The changing acoustic environment and potential impact on aquatic life communication) The presumption is that marine life has inhabited shallow seas and consequently adapted to the peculiarities of that environment. Anthropogenic change is the focus of this discussion in the context of both ambient noise and propagation. Commercial and recreational activities span a wide range of frequencies, areal extent, and exposure times, and their consequences are described with reference to the acoustic environment in the absence of this activity. The continuing change, both predictive and speculative, will be discussed with regard to aquatic life acoustic behavior.

Surface texture and wetting stability of polydimethylsiloxane coated with aluminum oxide at low temperature by atomic layer deposition

The performance of polydimethylsiloxane (PDMS) elastomer in many of its applications, including surface molding and replication, microcontact lithography, and microfluidic device structures, is strongly influenced by its surface properties. While PDMS polymer is simple to use, the surface hydrophobicity and adsorptive properties of PDMS limit its functionality, for example, in aqueous microfluidic applications. Atomic layer deposition (ALD) is a low temperature vapor phase thin film coating technique that has recently been used to modify and encapsulate a wide range of polymer materials. In this work, the authors investigate reactions that proceed when PDMS polymer films are treated with cyclic gas exposure sequences commonly used to perform aluminum oxide ALD. Film growth is characterized by electron and infrared spectroscopy and by contact angle goniometry for a range of surface treatments and postdeposition air exposure times. The authors find that trimethylaluminum/water ALD can produce a smooth and uniform film coating on PDMS at 25–50 °C and that cracks become visible under optical microscopy for films &amp;gt;100 Å thick. At moderate temperatures, unique buckled surface textures appear in the deposited coating, which are ascribed to substrate thermal expansion effects. Aluminum oxide coatings on native PDMS, as well as on PDMS pretreated with UV ozone or oxygen plasma, show a hydrophilic surface condition immediately after deposition, but the surface becomes more hydrophobic after 24–48 h in ambient air or under inert gas storage, likely due to organic species out-diffusion through defects in the ALD coating. Infrared analysis is also used to identify consistent mechanisms associated with subsurface ALD nucleation on cast PDMS layers. These results provide valuable insight into a means to reliably modify the surface of PDMS using vapor phase precursor/surface reactions.

Controlling the Invasive Diatom Didymosphenia geminata: An Ecotoxicity Assessment of Four Potential Biocides

In 2004, an invasive mat-forming freshwater diatom, Didymosphenia geminata (didymo), was found in New Zealand causing concern with regard to potential consequences for local freshwater ecosystems. A four-stage research program was initiated to identify methods to control D. geminata. This article reports the results of Stage 2, in which four potential control compounds [Gemex™ (a chelated copper formulation), EDTA, Hydrothol®191, and Organic Interceptor™ (a pine oil formulation)] selected in Stage 1 were evaluated for their biocidal efficacy on D. geminata and effects on non-target organisms using both artificial stream and laboratory trials. Artificial stream trials evaluated the mortality rates of D. geminata and fishes to three concentrations of the four biocides, whereas laboratory toxicity trials tested the response of green alga and cladocera to a range of biocide concentrations and exposure times. In artificial stream trials, Gemex and Organic Interceptor were the most effective biocides against D. geminata for a number of measured indices; however, exposure of fishes to Organic Interceptor resulted in high mortality rates. Laboratory toxicity testing indicated that Gemex might negatively affect sensitive stream invertebrates, based on the cladoceran sensitivity at the proposed river control dose. A decision support matrix evaluated the four biocides based on nine criteria stipulated by river stakeholders (effectiveness, non-target species impacts, stalk removal, degradation profile, risks to health and safety, ease of application, neutralization potential, cost, and local regulatory requirements) and Gemex was identified as the product warranting further refinement prior to an in-river trial.

Effects of nitrite concentration and exposure time on sulfide and methane production in sewer systems

Nitrite dosing is a promising technology to prevent sulfide and methane formation in sewers, due to the known inhibitory/toxic effect of nitrite on sulfate-reducing bacteria (SRB) and methanogenic Archaea (MA). The dependency of nitrite-induced inhibition on sulfide and methane producing activities of anaerobic sewer biofilms on nitrite levels and exposure time is investigated using a range of nitrite concentrations (40, 80, 120 mg-N/L) and exposure time up to 24 days. The recovery of these activities after the 24-day nitrite dosage was also monitored for more than two months. The inhibition level was found to be dependent on both nitrite concentration and exposure time, with stronger inhibition observed at higher nitrite concentrations and/or longer exposure time. However, the time required for achieving 50% recovery of both sulfate-reducing and methanogenic activities after the cessation of nitrite dosage only marginally depended on nitrite concentration. Model-based analysis of the recovery data showed that the recovery was likely due to the regrowth of SRB and methanogens. The lab studies and mathematical analysis supported the development of an intermittent dosing strategy, which was tested in a 1-km long rising main sewer. The field trial confirmed that intermittent dosing of nitrite can effectively reduce/prevent the formation of both sulfide and methane.