Preliminary Study on Treatment of Contaminated Groundwater from the Taylorville Gasifier Site

Groundwater and soil at the site of an abandoned coal gasification plant in Taylorville, Illinois have been contaminated with compounds associated with coal conversion process waters. A preliminary study to assess the feasibility of using ethanol as a means of increasing the solubility of compounds adsorbed within the soil matrix followed by treatment of the ethanol/groundwater extract in an expanded-bed anaerobic granular activated carbon (GAC) reactor was conducted. Results of the study indicate that compounds in the groundwater are highly adsorb able on GAC, and do not interfere with the anaerobic degradation of ethanol in the reactor. Soil extractions with varying ethanol/water ratios were able to remove many additional low water solubility compounds from the soil.ENR Contract Number HWR87035published or submitted for publicationis peer reviewe

Identification of a New Family of Enzymes with Potential \u3cem\u3eO\u3c/em\u3e-acetylpeptidoglycan esterase activity in both Gram-positive and Gram-negative bacteria

Background: The metabolism of the rigid bacterial cell wall heteropolymer peptidoglycan is a dynamic process requiring continuous biosynthesis and maintenance involving the coordination of both lytic and synthetic enzymes. The O-acetylation of peptidoglycan has been proposed to provide one level of control on these activities as this modification inhibits the action of the major endogenous lytic enzymes, the lytic transglycosylases. The O-acetylation of peptidoglycan also inhibits the activity of the lysozymes which serve as the first line of defense of host cells against the invasion of bacterial pathogens. Despite this central importance, there is a dearth of information regarding peptidoglycan O-acetylation and nothing has previously been reported on its de-acetylation. Results: Homology searches of the genome databases have permitted this first report on the identification of a potential family of O-Acetylpeptidoglycan esterases (Ape). These proteins encoded in the genomes of a variety of both Gram-negative and Gram-positive bacteria, including a number of important human pathogens such as species of Neisseria, Helicobacter, Campylobacter, and Bacillus anthracis, have been organized into three families based on amino acid sequence similarities with family 1 being further divided into three sub-families. The genes encoding these proteins are shown to be clustered with Peptidoglycan O-acetyltransferases (Pat) and in some cases, together with other genes involved in cell wall metabolism. Representative bacteria that encode the Ape proteins were experimentally shown to produce O-acetylated peptidoglycan. Conclusion: The hypothetical proteins encoded by the pat and ape genes have been organized into families based on sequence similarities. The Pat proteins have sequence similarity to Pseudomonas aeruginosa AlgI, an integral membrane protein known to participate in the O-acetylation of the exopolysaccaride, alginate. As none of the bacteria that harbor the pat genes produce alginate, we propose that the Pat proteins serve to O-acetylate peptidoglycan which is known to be a maturation event occurring in the periplasm. The Ape sequences have amino acid sequence similarity to the CAZy CE 3 carbohydrate esterases, a family previously known to be composed of only O-acetylxylan esterases. They are predicted to contain the α/β hydrolase fold associated with the GDSL and TesA hydrolases and they possess the signature motifs associated with the catalytic residues of the CE3 esterases. Specific signature sequence motifs were identified for the Ape proteins which led to their organization into distinct families. We propose that by expressing both Pat and Ape enzymes, bacteria would be able to obtain a high level of localized control over the degradation of peptidoglycan through the attachment and removal of O-linked acetate. This would facilitate the efficient insertion of pores and flagella, localize spore formation, and control the level of general peptidoglycan turnover

Use of iron salts for control of activated sludge bulking caused by sphaerotilus

A continuing operational problem encountered in the activated sludge system is sludge bulking. While there are several causative agents for this bulking, the filamentous bacterium Sphaerotilus is one of the more common. Control of the growth of this organism will help to eliminate sludge bulking as an operating problem in many activated sludge systems. Iron has been identified in the literature as a possible inhibitor to the growth of this bacterium. However, little is known about the mechanism of this inhibition. This study has shown that the adsorption of iron on Sphaerotilus is the major inhibitory mechanism. The layer of iron on the organism appears to block the transport of nutrients through the sheath and cell wall and hence inhibit the growth of this organism. The effectiveness of the iron compounds in this inhibition corresponds to the physical characteristics of the absorbed iron. Soluble iron complexes form a uniform layer so that the inhibitory effect is proportional to the iron adsorbed. Among the soluble complexes, the ferrous forms are more effective. These forms can penetrate the sheath and deposit on or near the cell wall resulting in greater inhibition. On the other hand, the ferric complexes are deposited on or in the sheath of the organism.U.S. Department of the InteriorU.S. Geological SurveyOpe

Identification of a new family of enzymes with potential O-acetylpeptidoglycan esterase activity in both Gram-positive and Gram-negative bacteria

BACKGROUND: The metabolism of the rigid bacterial cell wall heteropolymer peptidoglycan is a dynamic process requiring continuous biosynthesis and maintenance involving the coordination of both lytic and synthetic enzymes. The O-acetylation of peptidoglycan has been proposed to provide one level of control on these activities as this modification inhibits the action of the major endogenous lytic enzymes, the lytic transglycosylases. The O-acetylation of peptidoglycan also inhibits the activity of the lysozymes which serve as the first line of defense of host cells against the invasion of bacterial pathogens. Despite this central importance, there is a dearth of information regarding peptidoglycan O-acetylation and nothing has previously been reported on its de-acetylation. RESULTS: Homology searches of the genome databases have permitted this first report on the identification of a potential family of O-Acetylpeptidoglycan esterases (Ape). These proteins encoded in the genomes of a variety of both Gram-negative and Gram-positive bacteria, including a number of important human pathogens such as species of Neisseria, Helicobacter, Campylobacter, and Bacillus anthracis, have been organized into three families based on amino acid sequence similarities with family 1 being further divided into three sub-families. The genes encoding these proteins are shown to be clustered with Peptidoglycan O-acetyltransferases (Pat) and in some cases, together with other genes involved in cell wall metabolism. Representative bacteria that encode the Ape proteins were experimentally shown to produce O-acetylated peptidoglycan. CONCLUSION: The hypothetical proteins encoded by the pat and ape genes have been organized into families based on sequence similarities. The Pat proteins have sequence similarity to Pseudomonas aeruginosa AlgI, an integral membrane protein known to participate in the O-acetylation of the exopolysaccaride, alginate. As none of the bacteria that harbor the pat genes produce alginate, we propose that the Pat proteins serve to O-acetylate peptidoglycan which is known to be a maturation event occurring in the periplasm. The Ape sequences have amino acid sequence similarity to the CAZy CE 3 carbohydrate esterases, a family previously known to be composed of only O-acetylxylan esterases. They are predicted to contain the α/β hydrolase fold associated with the GDSL and TesA hydrolases and they possess the signature motifs associated with the catalytic residues of the CE3 esterases. Specific signature sequence motifs were identified for the Ape proteins which led to their organization into distinct families. We propose that by expressing both Pat and Ape enzymes, bacteria would be able to obtain a high level of localized control over the degradation of peptidoglycan through the attachment and removal of O-linked acetate. This would facilitate the efficient insertion of pores and flagella, localize spore formation, and control the level of general peptidoglycan turnover

Incorporating a rule-based model of judgment into a wastewater treatment plant design optimization model

The use of a rule-based modeling technique for the formal consideration of poorly modeled issues in a water quality management problem is illustrated in the context of wastewater treatment plant design. Sludge bulking is a poorly understood problem in activated sludge wastewater treatment plants. An engineer must use judgement gained from experience when he designs an activated sludge plant to prevent bulking from causing the plant to fail. An attempt was made to use fuzzy logic in order to model that judgement. Results from research were taken from the literature and used independently as constraints to an activated sludge wastewater plant design optimization model to see their effect on the optimal design. Some of the research results were then formulated as rules in a rule-based system which relates design variable values to the likelihood of a design experiencing bulking problems. The weights of association of those rules to the conclusion that a given design would experience bulking problems and the logical interaction of those rules were calibrated using an experienced engineer's evaluation of a set of 15 plant designs. The consistency of the engineer's and the judgement model's evaluations were then checked with a second set of 15 designs. The model of judgement could be used to evaluate the bulking potential of any design. In the particular example developed, the judgement model was incorporated into a wastewater treatment plant design optimization model so that the cost effectiveness of constraint combinations could be examined. The tradeoff between cost and the likelihood of experiencing bulking problems was examined for a typical plant design problem.U.S. Department of the InteriorU.S. Geological SurveyOpe

Nonlinear programming model of a wastewater treatment system: Sensitivity analysis and a robustness constraint

A method for sensitivity analysis in nonlinear programming is described and then illustrated using a least-cost model of a secondary wastewater treatment system. A sensitivity equation approach is used to calculate normalized sensitivity coefficients, which approximate the percent changes in model variables and objective function due to a small parameter variation. Design changes predicted by the sensitivity coefficients are confirmed by a perturbation analysis of the optimal solution. Sensitivity concepts are used to develop a robustness measure which is incorporated into the constraint set of the nonlinear model. Robustness is narrowly defined as the ability of a model solution to maintain a level of performance that meets the system design criteria even if the actual values of model parameters are not exactly the same as the values assumed for design. A gradient optimization procedure is used to examine the tradeoff between total cost and the robustness measure. A preliminary analysis shows that the trends in robust wastewater treatment plant design are in direct conflict with the optimal decisions obtained when minimizing cost without a constraint on robustness but are in agreement with those designs observed to work in practice. The robustness constraint method presented should be applicable to other optimization models of water resources systems.U.S. Department of the InteriorU.S. Geological SurveyOpe

Workstation environment for wastewater treatment design using AI and mathematical models

This research explores the use of computer-based environments to facilitate environmental engineering decision making. A prototype system is developed for wastewater treatment plant design as an exploration tool to demonstrate the techniques and principles proposed. Several mathematical techniques, interactive graphic displays, and friendly user interfaces are used. The mathematical techniques are: (1) mass and water balances for an analysis program for wastewater treatment plant design, (2) a rule-based system for sludge bulking judgment, and (3) a standard processor for checking a design against existing design standards. The interactive graphic displays provide visual data for effective data manipulation, and the friendly user interfaces are designed for engineers who are not necessarily computer experts.U.S. Department of the InteriorU.S. Geological SurveyOpe

Mathematical models and optimization techniques for use in analysis and design of wastewater treatment systems

A mathematical framework is developed for use in the design of a secondary wastewater treatment system. Mathematical models predicting the performance of various unit processes are used to construct a comprehensive system model. Three efficient optimization approaches to generate cost effective system designs are studied. The first approach transcribes the comprehensive system model into a nonlinear program that includes 64 variables and 58 constraints. A generalized reduced gradient algorithm is applied to solve this model. The second approach uses an existing algorithm for solving generalized geometric programs. Partitioning of model variables into two sets is necessary. A number of geometric programming subproblems resulting from the partitioning are solved. The third approach decomposes the wastewater system into a liquid and a sludge subsystem. The liquid subsystem is optimally designed, while the sludge subsystem design includes embedded optimization steps. The overall optimal design is obtained from coordination between the two subsystem designs. The comprehensive system model can be used as a tool for the analysis of process performance. Important insights about process design, modeling, and integration can be gained by exercising the model. Potentially fruitful areas for research can also be identified. This is illustrated through the use of an example problem.U.S. Department of the InteriorU.S. Geological SurveyOpe

Turing instabilities in a mathematical model for signaling networks

GTPase molecules are important regulators in cells that continuously run through an activation/deactivation and membrane-attachment/membrane-detachment cycle. Activated GTPase is able to localize in parts of the membranes and to induce cell polarity. As feedback loops contribute to the GTPase cycle and as the coupling between membrane-bound and cytoplasmic processes introduces different diffusion coefficients a Turing mechanism is a natural candidate for this symmetry breaking. We formulate a mathematical model that couples a reaction-diffusion system in the inner volume to a reaction-diffusion system on the membrane via a flux condition and an attachment/detachment law at the membrane. We present a reduction to a simpler non-local reaction-diffusion model and perform a stability analysis and numerical simulations for this reduction. Our model in principle does support Turing instabilities but only if the lateral diffusion of inactivated GTPase is much faster than the diffusion of activated GTPase.Comment: 23 pages, 5 figures; The final publication is available at http://www.springerlink.com http://dx.doi.org/10.1007/s00285-011-0495-

Impact of Spironolactone on Longitudinal Changes in Health-Related Quality of Life in the Treatment of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist Trial

BACKGROUND: Heart failure (HF) with preserved ejection fraction patients have equally impaired health-related quality of life (HRQL) compared with those with HF with reduced ejection fraction, but limited studies have evaluated the impact of therapies on changes in HRQL. METHODS AND RESULTS: Patients ≥50 years of age, with symptomatic HF and left ventricular ejection fraction ≥45%, were enrolled in Treatment of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist (TOPCAT) and randomized to spironolactone or placebo. Patients completed the Kansas City Cardiomyopathy Questionnaire (KCCQ), which was the primary HRQL instrument, and EQ5D visual analog scale at baseline, 4 months, 12 months, and annually thereafter. McMaster Overall Treatment Evaluation was assessed at 4 and 12 months to assess global change scores. Change scores (+SD) were calculated to determine between-group differences, and multivariable repeated-measures models were created to identify other factors associated with change scores. Paired KCCQ data were available for 91.7% of 3445 TOPCAT patients. By 4 months, the mean change in KCCQ was 7.7±16 and mean change in EQ5D visual analog scale was 4.7±16. Adjusted mean changes in KCCQ for the spironolactone group were significantly better than those for the placebo group at 4-month (1.54 better; P=0.002), 12-month (1.35 better; P=0.02), and 36-month (1.86 better; P=0.02) visits. No between-group differences in EQ5D visual analog scale change scores or McMaster Overall Treatment Evaluation were noted. Older age, obesity, current smoking, New York Heart Association class III/IV, and comorbid illnesses were associated with declines in KCCQ scores. Use of spironolactone was an independent predictor of improved KCCQ scores. CONCLUSIONS: In symptomatic HF with preserved ejection fraction patients, use of spironolactone was associated with an improvement in HF-specific HRQL. Several modifiable risk factors were associated with HRQL deterioration. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00094302