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Segmentation of Three Dimensional Cell Culture Models from aSingle Focal Plane

Description: Three dimensional cell culture models offer new opportunities for development of computational techniques for segmentation and localization. These assays have a unique signature of a clump of cells that correspond to a functioning colony. Often the nuclear compartment is labeled and then imaged with fluorescent microscopy to provide context for protein localization. These colonies are first delineated from background using the level set method. Within each colony, nuclear regions are then bounded by their center of mass through radial voting, and a local neighborhood for each nucleus is established through Voronoi tessellation. Finally, the level set method is applied again within each Voronoi region to delineate the nuclear compartment. The paper concludes with the application of the proposed method to a dataset of experimental data demonstrating a stable solution when iterative radial voting and level set methods are used synergistically.
Date: November 1, 2006
Creator: Chang, Hang & Parvin, Bahram
Partner: UNT Libraries Government Documents Department

Connecting the molecular scale to the continuum scale for diffusion processes in smectite-rich porous media

Description: In this paper, we address the manner in which the continuum-scale diffusive properties of smectite-rich porous media arise from their molecular- and pore-scale features. Our starting point is a successful model of the continuum-scale apparent diffusion coefficient for water tracers and cations which decomposes it as a sum of pore-scale terms describing diffusion in macropore and interlayer 'compartments.' We then apply molecular dynamics (MD) simulations to determine molecular-scale diffusion coefficients D{sub interlayer} of water tracers and representative cations (Na{sup +}, Cs{sup +}, Sr{sup 2+}) in Na-smectite interlayers. We find that a remarkably simple expression relates D{sub interlayer} to the pore-scale parameter {delta}{sub nanopore} {<=} 1, a constrictivity factor that accounts for the lower mobility in interlayers as compared to macropores: {delta}{sub nanopore} = D{sub interlayer}/D{sub 0}, where D{sub 0} is the diffusion coefficient in bulk liquid water. Using this scaling expression, we can accurately predict the apparent diffusion coefficients of tracer H{sub 2}O, Na{sup +}, Sr{sup 2+} and Cs{sup +}+ in compacted Na-smectite-rich materials.
Date: December 1, 2009
Creator: Bourg, I.C. & Sposito, G.
Partner: UNT Libraries Government Documents Department

Quantitative representation of three-dimensional cell culturemodels

Description: Three-dimensional mammary cell culture models offer new opportunities for the development of computational techniques for segmentation, localization, and multicellular organization. Under normal conditions, these assays form a symmetrical, hollow structure, which is necessary for their functional operation. Often, the nuclear compartments are labeled, which provides context for quantitative protein localization or colony structure through fluorescent microscopy. These colonies are first delineated from the background using the level set method. Within each colony, nuclear regions are then bounded by their center of mass through iterative radial voting, and a local neighborhood for each nucleus is established through Voronoi tessellation. Finally, the level set method is applied again within each Voronoi region to delineate the nuclear compartment. The paper concludes with the application of the proposed method to a set of experimental data demonstrating a stable solution when iterative radial voting and level set methods are used synergistically. Furthermore, segmented colonies are characterized for architectural changes as a result of ionizing radiation.
Date: February 1, 2007
Creator: Chang, Hang; Park, Catherine & Parvin, Bahram
Partner: UNT Libraries Government Documents Department

Communication Between the Cell Membrane and the Nucleus: Role of Protein Compartmentalization

Description: Understanding how the information is conveyed from outside to inside the cell is a critical challenge for all biologists involved in signal transduction. The flow of information initiated by cell-cell and cell-extracellular matrix contacts is mediated by the formation of adhesion complexes involving multiple proteins. Inside adhesion complexes, connective membrane skeleton (CMS) proteins are signal transducers that bind to adhesion molecules, organize the cytoskeleton, and initiate biochemical cascades. Adhesion complex-mediated signal transduction ultimately directs the formation of supramolecular structures in the cell nucleus, as illustrated by the establishment of multi complexes of DNA-bound transcription factors, and the redistribution of nuclear structural proteins to form nuclear subdomains. Recently, several CMS proteins have been observed to travel to the cell nucleus, suggesting a distinctive role for these proteins in signal transduction. This review focuses on the nuclear translocation of structural signal transducers of the membrane skeleton and also extends our analysis to possible translocation of resident nuclear proteins to the membrane skeleton. This leads us to envision the communication between spatially distant cellular compartments (i.e., membrane skeleton and cell nucleus) as a bidirectional flow of information (a dynamic reciprocity) based on subtle multilevel structural and biochemical equilibria. At one level, it is mediated by the interaction between structural signal transducers and their binding partners, at another level it may be mediated by the balance and integration of signal transducers in different cellular compartments.
Date: October 21, 1998
Creator: Lelievre, Sophie A & Bissell, Mina J
Partner: UNT Libraries Government Documents Department

Dissecting Regional Variations in Stress Fiber Mechanics in Living Cells with Laser Nanosurgery

Description: The ability of a cell to distribute contractile stresses across the extracellular matrix in a spatially heterogeneous fashion underlies many cellular behaviors, including motility and tissue assembly. Here we investigate the biophysical basis of this phenomenon by using femtosecond laser nanosurgery to measure the viscoelastic recoil and cell-shape contributions of contractile stress fibers (SFs) located in specific compartments of living cells. Upon photodisruption and recoil, myosin light chain kinase-dependent SFs located along the cell periphery display much lower effective elasticities and higher plateau retraction distances than Rho-associated kinase-dependent SFs located in the cell center, with severing of peripheral fibers uniquely triggering a dramatic contraction of the entire cell within minutes of fiber irradiation. Image correlation spectroscopy reveals that when one population of SFs is pharmacologically dissipated, actin density flows toward the other population. Furthermore, dissipation of peripheral fibers reduces the elasticity and increases the plateau retraction distance of central fibers, and severing central fibers under these conditions triggers cellular contraction. Together, these findings show that SFs regulated by different myosin activators exhibit different mechanical properties and cell shape contributions. They also suggest that some fibers can absorb components and assume mechanical roles of other fibers to stabilize cell shape.
Date: March 2, 2010
Creator: Tanner, Kandice; Boudreau, Aaron; Bissell, Mina J & Kumar, Sanjay
Partner: UNT Libraries Government Documents Department

Epimorphin Functions as a Key Morphoregulator for Mammary Epithelial Cells

Description: Hepatocyte growth factor (HGF) and EGF have been reported to promote branching morphogenesis of mammary epithelial cells. We now show that it is epimorphin that is primarily responsible for this phenomenon. In vivo, epimorphin was detected in the stromal compartment but not in lumenal epithelial cells of the mammary gland; in culture, however, a subpopulation of mammary epithelial cells produced significant amounts of epimorphin. When epimorphin-expressing epithelial cell clones were cultured in collagen gels they displayed branching morphogenesis in the presence of HGF, EGF, keratinocyte growth factor, or fibroblast growth factor, a process that was inhibited by anti-epimorphin but not anti-HGF antibodies. The branch length, however, was roughly proportional to the ability of the factors to induce growth. Accordingly, epimorphin-negative epithelial cells simply grew in a cluster in response to the growth factors and failed to branch. When recombinant epimorphin was added to these collagen gels, epimorphin-negative cells underwent branching morphogenesis. The mode of action of epimorphin on morphogenesis of the gland, however, was dependent on how it was presented to the mammary cells. If epimorphin was overexpressed in epimorphin-negative epithelial cells under regulation of an inducible promoter or was allowed to coat the surface of each epithelial cell in a nonpolar fashion, the cells formed globular, alveoli-like structures with a large central lumen instead of branching ducts. This process was enhanced also by addition of HGF, EGF, or other growth factors and was inhibited by epimorphin antibodies. These results suggest that epimorphin is the primary morphogen in the mammary gland but that growth factors are necessary to achieve the appropriate cell numbers for the resulting morphogenesis to be visualized.
Date: October 13, 1997
Creator: Hirai, H.; Lochter, A.; Galosy, S.; Koshida, S.; Niwa, S. & Bissell, M.J.
Partner: UNT Libraries Government Documents Department

Effects of Heavy, Tracked-Vehicle Disturbance on Forest Soil Properties at Fort Benning, Georgia

Description: The purpose of this report is to describe the effects of heavy, tracked-vehicle disturbance on various measures of soil quality in training compartment K-11 at Fort Benning, Georgia. Predisturbance soil sampling in April and October of 2002 indicated statistically significant differences in soil properties between upland and riparian sites. Soil density was less at riparian sites, but riparian soils had significantly greater C and N concentrations and stocks than upland soils. Most of the C stock in riparian soils was associated with mineral-associated organic matter (i.e., the silt + clay fraction physically separated from whole mineral soil). Topographic differences in soil N availability were highly dependent on the time of sampling. Riparian soils had higher concentrations of extractable inorganic N than upland soils and also exhibited significantly greater soil N availability during the spring sampling. The disturbance experiment was performed in May 2003 by driving a D7 bulldozer through the mixed pine/hardwood forest. Post-disturbance sampling was limited to upland sites because training with heavy, tracked vehicles at Fort Benning is generally confined to upland soils. Soil sampling approximately one month after the experiment indicated that effects of the bulldozer were limited primarily to the forest floor (O-horizon) and the surface (0-10 cm) mineral soil. O-horizon dry mass and C stocks were significantly reduced, relative to undisturbed sites, and there was an indication of reduced mineral soil C stocks in the disturbance zone. Differences in the surface (0-10 cm) mineral soil also indicated a significant increase in soil density as a result of disturbance by the bulldozer. Although there was some tendency for greater soil N availability in disturbed soils, the changes were not significantly different from undisturbed controls. It is expected that repeated soil disturbance over time, which will normally occur in a military training area, would simply intensify the ...
Date: May 20, 2004
Creator: Garten, C.T.,JR.
Partner: UNT Libraries Government Documents Department

GROWTH REGULATION IN ROUS SARCOMA VIRUS INFECTED CHICKEN EMBRYO FIBROBLASTS: THE ROLE OF THE src GENE

Description: We report here a study of the mechanisms leading to loss of growth control in chicken embryo fibroblasts transformed by Rous sarcoma virus (RSV). We have been particularly concerned with the role of the src gene in this process, and have used RSV mutants temperature sensitive (ts) for transformation to investigate the nature of the growth regulatory lesion. The two principal findings were (1) the stationary phase of the cell cycle (G{sub 1}) in chick embryo fibroblasts seems to have two distinct regulatory compartments (using the terminology of Brooks et al. we refer to these as 'Q' and 'A' states). When rendered stationary at 41.5 C by serum deprivation, normal cells enter a Q state, but cells infected with the ts-mutant occupy an A state. (2) Whereas normal cells can occupy either state depending on culture conditions, the ts-infected cells, at 41.5 C, do not seem to enter Q even though a known src gene product, a kinase, is reported to be inactive at this temperature. We discuss the possibility that viral factors other than the active src protein kinase influence growth control in infected cultures.
Date: July 1, 1980
Creator: Parry, G.; Bartholomew, J.A. & Blssell, M.J.
Partner: UNT Libraries Government Documents Department

Risk assessment framework for geologic carbon sequestration sites

Description: We have developed a simple and transparent approach for assessing CO{sub 2} and brine leakage risk associated with CO{sub 2} injection at geologic carbon sequestration (GCS) sites. The approach, called the Certification Framework (CF), is based on the concept of effective trapping, which takes into account both the probability of leakage from the storage formation and impacts of leakage. The effective trapping concept acknowledges that GCS can be safe and effective even if some CO{sub 2} and brine were to escape from the storage formation provided the impact of such leakage is below agreed-upon limits. The CF uses deterministic process models to calculate expected well- and fault-related leakage fluxes and concentrations. These in turn quantify the impacts under a given leakage scenario to so-called 'compartments,' which comprise collections of vulnerable entities. The probabilistic part of the calculated risk comes from the likelihood of (1) the intersections of injected CO{sub 2} and related pressure perturbations with well or fault leakage pathways, and (2) intersections of leakage pathways with compartments. Two innovative approaches for predicting leakage likelihood, namely (1) fault statistics, and (2) fuzzy rules for fault and fracture intersection probability, are highlighted here.
Date: February 1, 2010
Creator: Oldenburg, C.; Jordan, P.; Zhang, Y.; Nicot, J.-P. & Bryant, S.L.
Partner: UNT Libraries Government Documents Department

Model Components of the Certification Framework for Geologic Carbon Sequestration Risk Assessment

Description: We have developed a framework for assessing the leakage risk of geologic carbon sequestration sites. This framework, known as the Certification Framework (CF), emphasizes wells and faults as the primary potential leakage conduits. Vulnerable resources are grouped into compartments, and impacts due to leakage are quantified by the leakage flux or concentrations that could potentially occur in compartments under various scenarios. The CF utilizes several model components to simulate leakage scenarios. One model component is a catalog of results of reservoir simulations that can be queried to estimate plume travel distances and times, rather than requiring CF users to run new reservoir simulations for each case. Other model components developed for the CF and described here include fault characterization using fault-population statistics; fault connection probability using fuzzy rules; well-flow modeling with a drift-flux model implemented in TOUGH2; and atmospheric dense-gas dispersion using a mesoscale weather prediction code.
Date: June 1, 2009
Creator: Oldenburg, Curtis M.; Bryant, Steven L.; Nicot, Jean-Philippe; Kumar, Navanit; Zhang, Yingqi; Jordan, Preston et al.
Partner: UNT Libraries Government Documents Department

Probability Estimation of CO2 Leakage Through Faults at Geologic Carbon Sequestration Sites

Description: Leakage of CO{sub 2} and brine along faults at geologic carbon sequestration (GCS) sites is a primary concern for storage integrity. The focus of this study is on the estimation of the probability of leakage along faults or fractures. This leakage probability is controlled by the probability of a connected network of conduits existing at a given site, the probability of this network encountering the CO{sub 2} plume, and the probability of this network intersecting environmental resources that may be impacted by leakage. This work is designed to fit into a risk assessment and certification framework that uses compartments to represent vulnerable resources such as potable groundwater, health and safety, and the near-surface environment. The method we propose includes using percolation theory to estimate the connectivity of the faults, and generating fuzzy rules from discrete fracture network simulations to estimate leakage probability. By this approach, the probability of CO{sub 2} escaping into a compartment for a given system can be inferred from the fuzzy rules. The proposed method provides a quick way of estimating the probability of CO{sub 2} or brine leaking into a compartment. In addition, it provides the uncertainty range of the estimated probability.
Date: November 1, 2008
Creator: Zhang, Yingqi; Oldenburg, Curt; Finsterle, Stefan; Jordan, Preston & Zhang, Keni
Partner: UNT Libraries Government Documents Department

Percolation-theory and fuzzy rule-based probability estimation of fault leakage at geologic carbon sequestration sites

Description: Leakage of CO{sub 2} and displaced brine from geologic carbon sequestration (GCS) sites into potable groundwater or to the near-surface environment is a primary concern for safety and effectiveness of GCS. The focus of this study is on the estimation of the probability of CO{sub 2} leakage along conduits such as faults and fractures. This probability is controlled by (1) the probability that the CO{sub 2} plume encounters a conductive fault that could serve as a conduit for CO{sub 2} to leak through the sealing formation, and (2) the probability that the conductive fault(s) intersected by the CO{sub 2} plume are connected to other conductive faults in such a way that a connected flow path is formed to allow CO{sub 2} to leak to environmental resources that may be impacted by leakage. This work is designed to fit into the certification framework for geological CO{sub 2} storage, which represents vulnerable resources such as potable groundwater, health and safety, and the near-surface environment as discrete 'compartments'. The method we propose for calculating the probability of the network of conduits intersecting the CO{sub 2} plume and one or more compartments includes four steps: (1) assuming that a random network of conduits follows a power-law distribution, a critical conduit density is calculated based on percolation theory; for densities sufficiently smaller than this critical density, the leakage probability is zero; (2) for systems with a conduit density around or above the critical density, we perform a Monte Carlo simulation, generating realizations of conduit networks to determine the leakage probability of the CO{sub 2} plume (P{sub leak}) for different conduit length distributions, densities and CO{sub 2} plume sizes; (3) from the results of Step 2, we construct fuzzy rules to relate P{sub leak} to system characteristics such as system size, CO{sub 2} plume size, and ...
Date: May 1, 2009
Creator: Zhang, Y.; Oldenburg, C.M. & Finsterle, S.
Partner: UNT Libraries Government Documents Department

Case studies of the application of the Certification Framework to two geologic carbon sequestration sites

Description: We have developed a certification framework (CF) for certifying that the risks of geologic carbon sequestration (GCS) sites are below agreed-upon thresholds. The CF is based on effective trapping of CO2, the proposed concept that takes into account both the probability and impact of CO2 leakage. The CF uses probability estimates of the intersection of conductive faults and wells with the CO2 plume along with modeled fluxes or concentrations of CO2 as proxies for impacts to compartments (such as potable groundwater) to calculate CO2 leakage risk. In order to test and refine the approach, we applied the CF to (1) a hypothetical large-scale GCS project in the Texas Gulf Coast, and (2) WESTCARB's Phase III GCS pilot in the southern San Joaquin Valley, California.
Date: November 1, 2008
Creator: Oldenburg, Curtis M.; Nicot, J.-P. & Bryant, S.L.
Partner: UNT Libraries Government Documents Department

Spectral analysis for evaluation of myocardial tracers for medical imaging

Description: Kinetic analysis of dynamic tracer data is performed with the goal of evaluating myocardial radiotracers for cardiac nuclear medicine imaging. Data from experiments utilizing the isolated rabbit heart model are acquired by sampling the venous blood after introduction of a tracer of interest and a reference tracer. We have taken the approach that the kinetics are properly characterized by an impulse response function which describes the difference between the reference molecule (which does not leave the vasculature) and the molecule of interest which is transported across the capillary boundary and is made available to the cell. Using this formalism we can model the appearance of the tracer of interest in the venous output of the heart as a convolution of the appearance of the reference tracer with the impulse response. In this work we parameterize the impulse response function as the sum of a large number of exponential functions whose predetermined decay constants form a spectrum, and each is required only to have a nonnegative coefficient. This approach, called spectral analysis, has the advantage that it allows conventional compartmental analysis without prior knowledge of the number of compartments which the physiology may require or which the data will support.
Date: October 11, 2000
Creator: Huesman, Ronald H.; Reutter, Bryan W. & Marshall, Robert C.
Partner: UNT Libraries Government Documents Department

IMPROVED APPROACHES TO DESIGN OF POLYMER GEL TREATMENTS IN MATURE OIL FIELDS: FIELD DEMONSTRATION IN DICKMAN FIELD, NESS COUNTY, KANSAS

Description: This report describes the results of the one-year project entitled ''Improved Approaches to Design of Polymer Gel Treatments in Mature Oil Fields: Field Demonstration in Dickman Field, Ness County, Kansas''. The project was a 12-month collaboration of Grand Mesa Operating Company (a small independent), TIORCO Inc. (a company focused on improved recovery technology) and the University of Kansas. The study undertook tasks to determine an optimum polymer gel treatment design in Mississippian reservoirs, demonstrate application, and evaluate the success of the program. The project investigated geologic and engineering parameters and cost-effective technologies required for design and implementation of effective polymer gel treatment programs in the Mississippian reservoir in the Midcontinent. The majority of Mississippian production in Kansas occurs at or near the top of the Mississippian section just below the regional sub-Pennsylvanian unconformity and karst surface. Dickman Field with the extremely high water cuts and low recovery factors is typical of Mississippian reservoirs. Producibility problems in these reservoirs include inadequate reservoir characterization, drilling and completion design problems, and most significantly extremely high water cuts and low recovery factors that place continued operations at or near their economic limits. Geologic, geophysical and engineering data were integrated to provide a technical foundation for candidate selection and treatment design. Data includes core, engineering data, and 3D seismic data. Based on technical and economic considerations a well was selected for gel-polymer treatment (Grand Mesa Operating Company Tilley No.2). The treatment was not successful due to the small amount of polymer that could be injected. Data from the initial well and other candidates in the demonstration area was analyzed using geologic, geophysical and engineering data. Based on the results of the treatment and the integrated reservoir characterization it was determined that a second polymer-gel treatment could not be justified. The Mississippian reservoir at Dickman Field ...
Date: November 30, 2004
Creator: Fowler, Ronald
Partner: UNT Libraries Government Documents Department

A fugacity-based indoor residential pesticide fate model

Description: Dermal and non-dietary pathways are potentially significant exposure pathways to pesticides used in residences. Exposure pathways include dermal contact with residues on surfaces, ingestion from hand- and object-to-mouth activities, and absorption of pesticides into food. A limited amount of data has been collected on pesticide concentrations in various residential compartments following an application. But models are needed to interpret this data and make predictions about other pesticides based on chemical properties. In this paper, we propose a mass-balance compartment model based on fugacity principles. We include air (both gas phase and aerosols), carpet, smooth flooring, and walls as model compartments. Pesticide concentrations on furniture and toys, and in food, are being added to the model as data becomes available. We determine the compartmental fugacity capacity and mass transfer-rate coefficient for wallboard as an example. We also present the framework and equations needed for a dynamic mass-balance model.
Date: June 1, 2002
Creator: Bennett, Deborah H.; Furtaw, Edward J. & McKone, Thomas E.
Partner: UNT Libraries Government Documents Department

GROWTH REGULATION IN RSV INFECTED CHECKEN EMBRYO FIBROBLASTS: THE ROLE OF THE src GENE

Description: The relationship between growth regulation and cell transformation has been studied in many cultured cell lines transformed by a range of oncogenic agents. The main conclusion derived from these investigations is that the nature of the growth regulatory lesion in transformed cells is a function of the agent used to induce transformation. For example, when 3T3 fibroblasts are rendered stationary by serum deprivation, normal cells accumulate in G{sub 1} but SV40 transformed cells are arrested at all stages of the cell cycle. In contrast, 3T3 cells transformed with Rous sarcoma virus B77, accumulate in G{sub 1} upon serum deprivation. This is also true when mouse sarcoma virus (MSV) is used as the transforming agent. MSV-transformed cells accumulate in G{sub 1}, just as do normal cells. In this letter we report a detailed study of the mechanisms leading to loss of growth control in chicken embryo fibroblasts transformed by Rous sarcoma virus (RSV). We have been particularly concerned with the role of the src gene in the process, and have used RSV mutants temperature sensitive (ts) for transformation to investigate the nature of the growth regulatory lesion. Two principal findings have emerged: (a) the stationary phase of the cell cycle (G{sub 1}) in chick embryo fibroblasts has two distinct compartments, (for simplicity referred to as G{sub 1} and G{sub 0} states), (b) when rendered stationary at 41.5{sup o} by serum deprivation, normal cells enter a G{sub 0}-like state, but cells infected with the ts-mutant occupy a G{sub 1} state, even though a known src gene product, a kinase, should be inactive at this temperature. The possibility is discussed that viral factors other than the active src protein kinase influence growth control.
Date: March 1, 1980
Creator: Parry, G.; Bartholomew, J.C. & Bissell, M.J.
Partner: UNT Libraries Government Documents Department

Ballistic Resistance of Armored Passenger Vehicles: Test Protocols and Quality Methods

Description: This guide establishes a test methodology for determining the overall ballistic resistance of the passenger compartment of assembled nontactical armored passenger vehicles (APVs). Because ballistic testing of every piece of every component of an armored vehicle is impractical, if not impossible, this guide describes a testing scheme based on statistical sampling of exposed component surface areas. Results from the test of the sampled points are combined to form a test score that reflects the probability of ballistic penetration into the passenger compartment of the vehicle.
Date: July 1, 2005
Creator: Lacy, Jeffrey M. & Polk, Robert E.
Partner: UNT Libraries Government Documents Department

Consolidation of geologic studies of geopressured-geothermal resources in Texas. 1990 Annual report

Description: In a five-county area of South Texas, geopressured-geothermal reservoirs in the upper Wilcox Group colocated with heavy-oil reservoirs in the overlying Jackson Group. In 1990, research at the Bureau of Economic Geology concentrated on evaluating the potential of using geopressured-geothermal water for hot-water flooding of heavy-oil reservoirs. Favorable geothermal reservoirs are defined by thick deltaic sandstones and growth-fault-bounded compartments. Potential geothermal reservoirs are present at a depth of 11,000 ft (3,350 m) to 15,000 ft (4,570 m) and contain water at temperatures of 350 F (177 C) to 383 F (195 C) in Fandango field, Zapata County. One potential geothermal reservoir sandstone in the upper Wilcox (R sandstone) is composed of a continuous sand body 100 ft (30 m) to greater than 200 ft (>61 m) thick. Fault blocks average 2 to 4 mi{sup 2} (5.2 to 10.4 km{sup 2}) in area.
Date: March 1, 1991
Creator: Raney, J.A.; Seni, S.J.; DuBar, J.R. & Walter, T.G.
Partner: UNT Libraries Government Documents Department

Human Mammary Luminal Epithelial Cells Contain Progenitors to Myoepithelial Cells

Description: The origin of the epithelial and myoepithelial cells in the human breast has not been delineated. In this study we have addressed whether luminal epithelial cells and myoepithelial cells are vertically connected, i.e., whether one is the precursor for the other. We used a primary culture assay allowing preservation of basic phenotypic traits of luminal epithelial and myoepithelial cells in culture. The two cell types were then separated immunomagnetically using antibodies directed against lineage-specific cell surface antigens into at best 100% purity. The cellular identity was ascertained by cytochemistry, immunoblotting, and 2-D gel electrophoresis. Luminal epithelial cells were identified by strong expression of cytokeratins 18 and 19 while myoepithelial cells were recognized by expression of vimentin and {alpha}-smooth muscle actin. We used a previously devised culture medium (CDM4) that allows vigorous expansion of proliferative myoepithelial cells and also devised a medium (CDM6) that allowed sufficient expansion of differentiated luminal epithelial cells based on addition of hepatocyte growth factor/scatter factor. The two different culture media supported each lineage for at least five passages without signs of interconversion. We used parallel cultures where we switched culture media, thus testing the ability of each lineage to convert to the other. Whereas the myoepithelial lineage showed no signs of interconversion, a subset of luminal epithelial cells, gradually, but distinctly, converted to myoepithelial cells. We propose that in the mature human breast, it is the luminal epithelial cell compartment that gives rise to myoepithelial cells rather than the other way around.
Date: February 1, 1999
Creator: Pechoux, Christine; Gudjonsson, Thorarinn; Ronnov-Jessen, Lone; Bissell, Mina J & Petersen, Ole
Partner: UNT Libraries Government Documents Department

Modeling the diffusion of Na+ in compacted water-saturated Na-bentonite as a function of pore water ionic strength

Description: Assessments of bentonite barrier performance in waste management scenarios require an accurate description of the diffusion of water and solutes through the barrier. A two-compartment macropore/nanopore model (on which smectite interlayer nanopores are treated as a distinct compartment of the overall pore space) was applied to describe the diffusion of {sup 22}Na{sup +} in compacted, water-saturated Na-bentonites and then compared with the well-known surface diffusion model. The two-compartment model successfully predicted the observed weak ionic strength dependence of the apparent diffusion coefficient (D{sub a}) of Na{sup +}, whereas the surface diffusion model did not, thus confirming previous research indicating the strong influence of interlayer nanopores on the properties of smectite clay barriers. Since bentonite mechanical properties and pore water chemistry have been described successfully with two-compartment models, the results in the present study represent an important contribution toward the construction of a comprehensive two-compartment model of compacted bentonite barriers.
Date: August 15, 2008
Creator: Bourg, I.C.; Sposito, G. & Bourg, A.C.M.
Partner: UNT Libraries Government Documents Department

Certification Framework Based on Effective Trapping for Geologic Carbon Sequestration

Description: We have developed a certification framework (CF) for certifying the safety and effectiveness of geologic carbon sequestration (GCS) sites. Safety and effectiveness are achieved if CO{sub 2} and displaced brine have no significant impact on humans, other living things, resources, or the environment. In the CF, we relate effective trapping to CO{sub 2} leakage risk which takes into account both the impact and probability of leakage. We achieve simplicity in the CF by using (1) wells and faults as the potential leakage pathways, (2) compartments to represent environmental resources that may be impacted by leakage, (3) CO{sub 2} fluxes and concentrations in the compartments as proxies for impact to vulnerable entities, (4) broad ranges of storage formation properties to generate a catalog of simulated plume movements, and (5) probabilities of intersection of the CO{sub 2} plume with the conduits and compartments. We demonstrate the approach on a hypothetical GCS site in a Texas Gulf Coast saline formation. Through its generality and flexibility, the CF can contribute to the assessment of risk of CO{sub 2} and brine leakage as part of the certification process for licensing and permitting of GCS sites around the world regardless of the specific regulations in place in any given country.
Date: January 15, 2009
Creator: Oldenburg, Curtis M.; Bryant, Steven L. & Nicot, Jean-Philippe
Partner: UNT Libraries Government Documents Department

A pilot study of energy efficient air cleaning for ozone

Description: A laboratory pilot study has been undertaken with the material that showed the most promise (high capacity and low pressure drop) based on the literature review and associated calculations. The best-performing air cleaner was a commercially available pleated filter that contained a thin layer of small activated carbon particles between two sheets of non-woven fibrous webbing. We will refer to this unit as the ''ozone filter'' although it is marketed for removal of volatile organic compounds (VOCs) from automobile passenger compartments. This pilot study strongly suggests that ozone air cleaning can be practical in commercial air handling systems; however, further tests are needed to assess air cleaner performance under a wider range of conditions.
Date: November 1, 2002
Creator: Gundel, Lara A.; Sullivan, Douglas P.; Katsapov, Gregory Y. & Fisk, William J.
Partner: UNT Libraries Government Documents Department

The Geochemical Earth Reference Model (GERM)

Description: The Geochemical Earth Reference Model (GERM) initiative is a grass- roots effort with the goal of establishing a community consensus on a chemical characterization of the Earth, its major reservoirs, and the fluxes between them. Long term goal of GERM is a chemical reservoir characterization analogous to the geophysical effort of the Preliminary Reference Earth Model (PREM). Chemical fluxes between reservoirs are included into GERM to illuminate the long-term chemical evolution of the Earth and to characterize the Earth as a dynamic chemical system. In turn, these fluxes control geological processes and influence hydrosphere-atmosphere-climate dynamics. While these long-term goals are clearly the focus of GERM, the process of establishing GERM itself is just as important as its ultimate goal. The GERM initiative is developed in an open community discussion on the World Wide Web (GERM home page is at http://www-ep.es.llnl. gov/germ/germ-home.html) that is mediated by a series of editors with responsibilities for distinct reservoirs and fluxes. Beginning with the original workshop in Lyons (March 1996) GERM is continued to be developed on the Internet, punctuated by workshops and special sessions at professional meetings. It is planned to complete the first model by mid-1997, followed by a call for papers for a February 1998 GERM conference in La Jolla, California.
Date: December 1, 1996
Creator: Staudigel, H.; Albarede, F.; Shaw, H.; McDonough, B. & White, W.
Partner: UNT Libraries Government Documents Department