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Integrated Ecogenomics Study for Bioremediation of Cr(VI) at Hanford 100H Area

Description: Hexavalent chromium is a widespread contaminant found in groundwater. In order to stimulate microbially mediated Cr(VI)-reduction, a poly-lactate compound was injected into Cr(VI)-contaminated aquifers at site 100H at Hanford. Investigation of bacterial community composition using high-density DNA microarray analysis of 16S rRNA gene products revealed a stimulation of Pseudomonas, Desulfovibrio and Geobacter species amongst others. Enrichment of these organisms coincided with continued Cr(VI) depletion. Functional gene-array analysis of DNA from monitoring well indicated high abundance of genes involved in nitrate-reduction, sulfate-reduction, iron-reduction, methanogenesis, chromium tolerance/reduction. Clone-library data revealed Psedomonas was the dominant genus in these samples. Based on above results, we conducted lab investigations to study the dominant anaerobic culturable microbial populations present at this site and their role in Cr(VI)-reduction. Enrichments using defined anaerobic media resulted in isolation of an iron-reducing, a sulfate-reducing and a nitrate-reducing isolate among several others. Preliminary 16S rDNA sequence analysis identified the isolates as Geobacter metallireducens, Pseudomonas stutzeri and Desulfovibrio vulgaris species respectively. The Pseudomonas isolate utilized acetate, lactate, glycerol and pyruvate as alternative carbon sources, and reduced Cr(VI). Anaerobic washed cell suspension of strain HLN reduced almost 95?M Cr(VI) within 4 hr. Further, with 100?M Cr(VI) as sole electron-acceptor, cells grew to 4.05 x 107 /ml over 24 h after an initial lag, demonstrating direct enzymatic Cr(VI) reduction coupled to growth. These results demonstrate that Cr(VI)-immobilization at Hanford 100H site could be mediated by direct microbial metabolism in addition to indirect chemical reduction of Cr(VI) by end-products of microbial activity.
Date: August 12, 2008
Creator: Chakraborty, Romy & Chakraborty, Romy
Partner: UNT Libraries Government Documents Department

Long-distance communication and signal amplication in systemic acquired resistance

Description: This review article summarizes the involvement and interaction between long-distance systemic acquired resistance (SAR) signals and details the recently discovered role of lysine catabolite pipecolic acid (Pip) in defense amplification and priming that allows plants to acquire immunity at the systemic level.
Date: February 22, 2013
Creator: Shah, Jyoti & Zeier, J├╝rgen
Partner: UNT College of Arts and Sciences

Measurement and Analysis of Gas Bubbles Near a Reference Electrode in Aqueous Solutions

Description: Bubble size distributions (BSDs) near a reference electrode (RE) in aqueous glycerol solutions of an electrolyte NaCl have been investigated under various gas superficial velocities (U{sub S}). BSD and voltage reading of the solution were measured by using a high-speed digital camera and a pH/voltage meter, respectively. The results show that bubble size (b) increases with liquid viscosity ({mu}{sub c}) and U{sub S}. Self-similarity is seen and can be described by the log-normal form of the continuous number frequency distribution. The result shows that b controls the voltage reading in each solution. As b increases, the voltage increases because of gas bubbles interrupting their electrolyte paths in the solutions. An analysis of bubble rising velocity reveals that Stokes Law should be used cautiously to describe the system. The fundamental equation for bubble formation was developed via Newton's second law of motion and shown to be the function of three dimensionless groups--Weber number, Bond number, and Capillary number. After linking an electrochemical principle in the practical application, the result indicates that the critical bubble size is {approx}177 {micro}m. Further analysis suggests that there may be 3000 to 70,000 bubbles generated on the anode surface depending on the size of initial bubbles and provides the potential cause of the efficiency drop observed in the practical application.
Date: October 1, 2005
Creator: Phongikaroon, Supathorn; Herrmann, Steve; Li, Shelly & Simpson, Michael
Partner: UNT Libraries Government Documents Department

RELAP5-3D Code Includes Athena Features and Models

Description: Version 2.3 of the RELAP5-3D computer program includes all features and models previously available only in the ATHENA version of the code. These include the addition of new working fluids (i.e., ammonia, blood, carbon dioxide, glycerol, helium, hydrogen, lead-bismuth, lithium, lithium-lead, nitrogen, potassium, sodium, and sodium-potassium) and a magnetohydrodynamic model that expands the capability of the code to model many more thermal-hydraulic systems. In addition to the new working fluids along with the standard working fluid water, one or more noncondensable gases (e.g., air, argon, carbon dioxide, carbon monoxide, helium, hydrogen, krypton, nitrogen, oxygen, sf6, xenon) can be specified as part of the vapor/gas phase of the working fluid. These noncondensable gases were in previous versions of RELAP5- 3D. Recently four molten salts have been added as working fluids to RELAP5-3D Version 2.4, which has had limited release. These molten salts will be in RELAP5-3D Version 2.5, which will have a general release like RELAP5-3D Version 2.3. Applications that use these new features and models are discussed in this paper.
Date: July 1, 2006
Creator: Riemke, Richard A.; Davis, Cliff B. & Schultz, Richard R.
Partner: UNT Libraries Government Documents Department

DEMONSTRATION OF MIXING AND TRANSFERRING SETTLING COHESIVE SLURRY SIMULANTS IN THE AY-102 TANK

Description: In support of Hanford's feed delivery of high level waste (HLW) to the Waste Treatment and Immobilization Plant (WTP), pilot-scale testing and demonstrations with simulants containing cohesive particles were performed as a joint collaboration between Savannah River National Laboratory (SRNL) and the Pacific Northwest National Laboratory (PNNL) staff. The objective of the demonstrations was to determine the impact that cohesive particle interactions in the simulants, and the resulting non-Newtonian rheology, have on tank mixing and batch transfer of large and dense seed particles. The work addressed the impacts cohesive simulants have on mixing and batch transfer performance in a pilot-scale system. Kaolin slurries with a range of wt% concentrations to vary the Bingham yield stress were used in all the non-Newtonian simulants. To study the effects of just increasing the liquid viscosity (no yield stress) on mixing and batch transfers, a glycerol/water mixture was used. Stainless steel 100 micron particles were used as seed particles due to their density and their contrasting color to the kaolin and glycerol. In support of Hanford's waste certification and delivery of tank waste to the Waste Treatment and Immobilization Plant (WTP), Savannah River National Laboratory (SRNL) was tasked by Washington River Protection Solutions (WRPS) to evaluate the effectiveness of mixing and transferring tank waste in a Double Shell Tank (DST) to the WTP Receipt Tank. The work addresses the impacts cohesive simulants have on mixing and batch transfer performance. This work is follow-on to the previous tasks 'Demonstration of Mixer Jet Pump Rotational Sensitivity on Mixing and Transfers of the AY-102 Tank' and 'Demonstration of Simulated Waste Transfers from Tank AY-102 to the Hanford Waste Treatment Facility'. The cohesive simulants were investigated and selected jointly by SRNL and PNNL and a white paper was written on this evaluation. The testing and demonstrations of cohesive ...
Date: January 3, 2012
Creator: Adamson, D. & Gauglitz, P.
Partner: UNT Libraries Government Documents Department

Structural and compositional modifications in lignin of transgenic alfalfa down-regulated in caffeic acid 3-O-methyltransferase and caffeoyl coenzyme A 3-O-methyltransferase

Description: Article on the structural and compositional modifications in lignin of transgenic alfalfa down-regulated in caffeic acid 3-O-methyltransferase and caffeoyl coenzyme A 3-O-methyltransferase.
Date: July 8, 2002
Creator: Marita, Jane M.; Ralph, John; Hatfield, Ronald D.; Guo, Dianjing; Chen, Fang & Dixon, R. A.
Partner: UNT College of Arts and Sciences

Solution structure of detergent micelles at conditions relevant to membrane protein crystallization.

Description: In this study small angle neutron scattering was used to characterize the formation of micelles in aqueous solutions of the detergents DMG and SPC as a function of detergent concentration and ionic strength of the solvent. The effects on the micelle structure of the additives glycerol and PEG, alone as well as in combination typical for actual membrane protein crystallization, were also explored. This research suggests that the micelles are cigar-like in form at the concentrations studied. The size of the micelles was observed to increase with increasing ionic strength but decrease with the addition of glycerol or PEG.
Date: July 2, 1999
Creator: Littrell, K.; Thiyagarajan, P.; Tiede, D. & Urban, V.
Partner: UNT Libraries Government Documents Department

Progress in the detection of single molecules in levitated droplets

Description: This report briefly describes a method for the detection of single molecules of rhodamine-6G in levitated droplets. 4 refs. CBS
Date: January 1, 1990
Creator: Whitten, W.B.; Ramsey, J.M. (Oak Ridge National Lab., TN (USA)); Arnold, S. (Polytechnic Inst. of Brooklyn, NY (USA)) & Bronk, B.V. (Chemical Research, Development and Engineering Center, Aberdeen Proving Ground, MD (USA))
Partner: UNT Libraries Government Documents Department

Natural convection heat transfer between arrays of horizontal cylinders and their enclosure

Description: The natural convection heat transfer between arrays of horizontal, heated cylinders and their isothermal, cooled enclosure was experimentally investigated. Four different cylinder arrays were used: two in-line and two staggered. Four fluids (air, water, 20 cs silicone, and 96% glycerine) were used with Prandtl numbers ranging from 0.705 to 13090.0. There was no significant change in the Nusselt number between isothermal and constant heat flux conditions of the cylinder arrays. The average heat transfer coefficient was most affected by the spacing between cylinders and the total surface area of the cylinder arrays. The enclosure reduced the expected increase in both the average and the local heat transfer coefficients caused by changing the inner body from an in-line arrangement to a staggered arrangement of comparable spacing. An increase in fluid viscosity reduced the influence of the geometric effects.
Date: January 1, 1984
Creator: Weaver, R.A. & Warrington, R.O.
Partner: UNT Libraries Government Documents Department

Cavity-enhanced spontaneous emission rates for rhodamine 6-G in levitated microdroplets

Description: Fluorescence decay kinetics of Rhodamine 6-G molecules in levitated glycerol microdroplets (4--20 microns in diameter) have been investigated to determine the effects of spherical cavity resonances on spontaneous emission rates. For droplet diameters greater than 10 microns, the fluorescence lifetime is essentially the same as in bulk glycerol. As the droplet diameter is decreased below 10 microns, bi-exponential decay behavior is observed with a slow component whose rate is similar to bulk glycerol, and a fast component whose rate is as much as a factor of 10 larger than the bulk decay rate. This fast component is attributed to cavity enhancement of the spontaneous emission rate and, within the weak coupling approximation, a value for the homogeneous linewidth at room temperature can be estimated from the fluorescence lifetime data.
Date: January 1, 1992
Creator: Barnes, M.D.; Whitten, W.B.; Ramsey, J.M. (Oak Ridge National Lab., TN (United States)) & Arnold, S. (Polytechnic Inst., of New York, Brooklyn, NY Microparticle Photophysics Lab. (United States))
Partner: UNT Libraries Government Documents Department

Approaches to the preservation of human granulocytes by freezing

Description: Because of its simplicity, the FDA assay can be used effectively as a screening test to eliminate procedures and treatments that are damaging to cells. In this context, a number of conclusions can be drawn from the data presented: (1) Exposure to 1 and 2 M glycerol at room temperature damages human granulocytes in a few minutes. Reducing the exposure temperature to 0/sup 0/C reduces the amount of injury substantially. (2) Human granulocytes respond to freezing and thawing in a manner typical of many mammalian cells in that they exhibit a maximum in survival at an optimum cooling rate slightly above 1/sup 0/C/min when combined with rapid warming. The use of rapid warming and a high (2 M) concentration of glycerol reduces the dependence of survival on cooling rate by broadening the range of rates over which survival is relatively high. (3) Human granulocytes show some sensitivity to dilution stresses since survival depends somewhat on the concentration of glycerol used and the severity of the dilution procedure. The reasons for the sharp decrease in cell viability following incubation of frozen-thawed granulocytes at 37/sup 0/C are not known. One possibility is that the phosphate buffered saline suspending medium used is not suitable for incubation at 37/sup 0/C. A second possibility is that some cell injury is not expressed at 0/sup 0/C and remains undetected by the FDA assay until the cells are incubated at 37/sup 0/C. There is also the possibility that lysosomal enzymes released by a few damaged cells in a sample will cause additional damage in other cells at 37/sup 0/C.
Date: January 1, 1979
Creator: Frim, J & Mazur, P
Partner: UNT Libraries Government Documents Department

Metallography of maraging 350 steel

Description: A technique for etching maraging 350 steel with Glyceregia is described. Surface activation procedures are integral to this technique. Microstructural features revealed by this technique are compared with those obtained with Kalling's reagent, Fry's reagent, and 5% Nital, three etchants commonly used to reveal microstructures of maraging steels. Features which may be simultaneously revealed using Glyceregia include prior austenite grain boundaries, martensitic structure, precipitates, titanium carbo-nitrides, and reverted austenite. The other etchants examined in this investigation typically reveal only a few of the microstructural features detailed above at any one time. 11 refs., 10 figs., 2 tabs.
Date: January 1, 1987
Creator: Hutson, S.M. & Merten, C.W.
Partner: UNT Libraries Government Documents Department

Cavity-enhanced spontaneous emission rates for rhodamine 6-G in levitated microdroplets

Description: Fluorescence decay kinetics of Rhodamine 6-G molecules in levitated glycerol microdroplets (4--20 microns in diameter) have been investigated to determine the effects of spherical cavity resonances on spontaneous emission rates. For droplet diameters greater than 10 microns, the fluorescence lifetime is essentially the same as in bulk glycerol. As the droplet diameter is decreased below 10 microns, bi-exponential decay behavior is observed with a slow component whose rate is similar to bulk glycerol, and a fast component whose rate is as much as a factor of 10 larger than the bulk decay rate. This fast component is attributed to cavity enhancement of the spontaneous emission rate and, within the weak coupling approximation, a value for the homogeneous linewidth at room temperature can be estimated from the fluorescence lifetime data.
Date: November 1, 1992
Creator: Barnes, M. D.; Whitten, W. B.; Ramsey, J. M. & Arnold, S.
Partner: UNT Libraries Government Documents Department