Resource Type

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A Modelica-based Model Library for Building Energy and Control Systems (open access)

A Modelica-based Model Library for Building Energy and Control Systems

This paper describes an open-source library with component models for building energy and control systems that is based on Modelica, an equation-based objectoriented language that is well positioned to become the standard for modeling of dynamic systems in various industrial sectors. The library is currently developed to support computational science and engineering for innovative building energy and control systems. Early applications will include controls design and analysis, rapid prototyping to support innovation of new building systems and the use of models during operation for controls, fault detection and diagnostics. This paper discusses the motivation for selecting an equation-based object-oriented language. It presents the architecture of the library and explains how base models can be used to rapidly implement new models. To demonstrate the capability of analyzing novel energy and control systems, the paper closes with an example where we compare the dynamic performance of a conventional hydronic heating system with thermostatic radiator valves to an innovative heating system. In the new system, instead of a centralized circulation pump, each of the 18 radiators has a pump whose speed is controlled using a room temperature feedback loop, and the temperature of the boiler is controlled based on the speed of the …
Date: April 7, 2009
Creator: Wetter, Michael
System: The UNT Digital Library
Synthesis and Characterization of Dimethylbis(2-pyridyl)borate Nickel(II) Complexes: Unimolecular Square-Planar to Square-Planar Rotation around Nickel(II) (open access)

Synthesis and Characterization of Dimethylbis(2-pyridyl)borate Nickel(II) Complexes: Unimolecular Square-Planar to Square-Planar Rotation around Nickel(II)

This article reports the synthesis, characterization, and solution dynamics of the novel nickel(II) complexes (dimethylbis(2-pyridyl)borate)(triphenylphosphine)nickel(II) chloride (4) and (dimethylbis(2-pyridyl)borate)nickel(II) acetylacetonate (6).
Date: April 7, 2014
Creator: Celaje, Jeff A.; Pennington-Boggio, Megan K.; Flaig, Robinson W.; Richmond, Michael G. & Williams, Travis J.
System: The UNT Digital Library
A DATA-CENTERED COLLABORATION PORTAL TO SUPPORT GLOBAL CARBON-FLUX ANALYSIS (open access)

A DATA-CENTERED COLLABORATION PORTAL TO SUPPORT GLOBAL CARBON-FLUX ANALYSIS

Carbon-climate, like other environmental sciences, has been changing. Large-scalesynthesis studies are becoming more common. These synthesis studies are often conducted by science teams that are geographically distributed and on datasets that are global in scale. A broad array of collaboration and data analytics tools are now available that could support these science teams. However, building tools that scientists actually use is hard. Also, moving scientists from an informal collaboration structure to one mediated by technology often exposes inconsistencies in the understanding of the rules of engagement between collaborators. We have developed a scientific collaboration portal, called fluxdata.org, which serves the community of scientists providing and analyzing the global FLUXNET carbon-flux synthesis dataset. Key things we learned or re-learned during our portal development include: minimize the barrier to entry, provide features on a just-in-time basis, development of requirements is an on-going process, provide incentives to change leaders and leverage the opportunity they represent, automate as much as possible, and you can only learn how to make it better if people depend on it enough to give you feedback. In addition, we also learned that splitting the portal roles between scientists and computer scientists improved user adoption and trust. The fluxdata.org portal …
Date: April 7, 2009
Creator: Agarwal, Deborah A.; Humphrey, Marty; Beekwilder, Norm; Jackson, Keith; Goode, Monte & van Ingen, Catharine
System: The UNT Digital Library
Semi-inclusive DIS:Factorization (open access)

Semi-inclusive DIS:Factorization

In this talk, we win present a QCD factorization theorem for the semi-inclusive deep-inelastic scattering with hadrons in the current fragmentation region detected at low transverse momentum.
Date: April 7, 2008
Creator: Yuan,F.
System: The UNT Digital Library
Dark Matter in the MSSM (open access)

Dark Matter in the MSSM

We have recently examined a large number of points in the parameter space of the phenomenological MSSM, the 19-dimensional parameter space of the CP-conserving MSSM with Minimal Flavor Violation. We determined whether each of these points satisfied existing experimental and theoretical constraints. This analysis provides insight into general features of the MSSM without reference to a particular SUSY breaking scenario or any other assumptions at the GUT scale. This study opens up new possibilities for SUSY phenomenology both in colliders and in astrophysical experiments. Here we shall discuss the implications of this analysis relevant to the study of dark matter.
Date: April 7, 2009
Creator: Cotta, R. C.; Gainer, J. S.; Hewett, J. L. & Rizzo, T. G.
System: The UNT Digital Library
Integrated Building Energy Systems Design Considering Storage Technologies (open access)

Integrated Building Energy Systems Design Considering Storage Technologies

The addition of storage technologies such as flow batteries, conventional batteries, and heat storage can improve the economic, as well as environmental attraction of micro-generation systems (e.g., PV or fuel cells with or without CHP) and contribute to enhanced demand response. The interactions among PV, solar thermal, and storage systems can be complex, depending on the tariff structure, load profile, etc. In order to examine the impact of storage technologies on demand response and CO2 emissions, a microgrid's distributed energy resources (DER) adoption problem is formulated as a mixed-integer linear program that can pursue two strategies as its objective function. These two strategies are minimization of its annual energy costs or of its CO2 emissions. The problem is solved for a given test year at representative customer sites, e.g., nursing homes, to obtain not only the optimal investment portfolio, but also the optimal hourly operating schedules for the selected technologies. This paper focuses on analysis of storage technologies in micro-generation optimization on a building level, with example applications in New York State and California. It shows results from a two-year research projectperformed for the U.S. Department of Energy and ongoing work. Contrary to established expectations, our results indicate that PV …
Date: April 7, 2009
Creator: Stadler, Michael; Marnay, Chris; Siddiqui, Afzal; Lai, Judy & Aki, Hirohisa
System: The UNT Digital Library
High Pressure - High Temperature Polymorphism in Ta: Resolving an Ongoing Experimental Controversy (open access)

High Pressure - High Temperature Polymorphism in Ta: Resolving an Ongoing Experimental Controversy

Phase diagrams of refractory metals remain essentially unknown. Moreover, there is an ongoing controversy over the high pressure (P) melting temperatures of these metals: results of diamond anvil cell (DAC) and shock wave experiments differ by at least a factor of two. From an extensive ab initio study on tantalum we discovered that the body-centered cubic phase, its physical phase at ambient conditions, transforms to another solid phase, possibly hexagonal omega phase, at high temperature (T). Hence the sample motion observed in DAC experiments is not due to melting but internal stresses accompanying a solid-solid transformation, as explained in more detail in our work. In view of our results on tantalum and previous work on molybdenum, as well as other published data, it is highly plausible that high-PT polymorphism is a general feature of Groups V and VI refractory metals.
Date: April 7, 2010
Creator: Burkovsky, L.; Chen, S. P.; Preston, D. L.; Belonoshko, A. B.; Rosengren, A.; Mikhaylushkin, A. S. et al.
System: The UNT Digital Library
Renewed Search for FUN (Fractionated and Unidentified Nuclear Effects) in Primitive Chondrites (open access)

Renewed Search for FUN (Fractionated and Unidentified Nuclear Effects) in Primitive Chondrites

Ca-Al-rich inclusions (CAIs) found in primitive chondrites record processes and conditions of the earliest solar system as they are the oldest known solid objects formed in the solar system [1,2]. CAIs with fractionation and unidentified nuclear anomalies (FUN CAIs; [3]) are very rare and thusfar found exclusively in CV carbonaceous chondrites (e.g., Allende and Vigarano)[4]. FUN CAIs are characterized by large nucleosynthetic anomalies in several elements (Ca, Ti, Si, Sr, Ba, Nd, and Sm), large mass-dependant isotope fractionation (Mg, Si, and O), and very little initial {sup 26}Al [4,5 and reference therein]. Formation of FUN CAIs by thermal processing of presolar dust aggregates prior to the injection of {sup 26}Al into the protoplanetary disk has been proposed. More recently [5] proposed that FUN CAIs formed from a protosolar molecular cloud after injection of {sup 26}Al but before {sup 26}Al and {sup 27}Al were completely homogenized. Therefore discovering more FUN CAIs to perform U-Pb and other short-lived chronometric dating will provide key constraints on the age of the solar system, the isotopic composition of the protosolar molecular cloud, the earliest stages of the thermal processing in the solar system and the timing of {sup 26}Al and other short-lived radionuclide injection into …
Date: April 7, 2011
Creator: Tollstrup, D L; Wimpenny, J B; Yin, Q -; Ebel, D S; Jacobsen, B & Hutcheon, I D
System: The UNT Digital Library
Transverse Spin Physics: Recent Developments (open access)

Transverse Spin Physics: Recent Developments

None
Date: April 7, 2008
Creator: Yuan,F.
System: The UNT Digital Library
Solid Solution Phases in the Olivine-Type LiMnPO4/MnPO4 System (open access)

Solid Solution Phases in the Olivine-Type LiMnPO4/MnPO4 System

Nonstoichiometry is reported in the LiMnPO{sub 4}/MnPO{sub 4} system for the first time. As lithium is removed from crystalline LiMnPO{sub 4} by chemical or electrochemical methods, the resulting two phase mixture consists of stoichiometric LiMnPO{sub 4} and a delithiated phase, Li{sub y}MnPO{sub 4}, whose lattice parameters depend upon the global extent of delithiation and on the crystalline domain size of the delithiated phase. This behavior is reproduced during electrochemical insertion of lithium. Again, no evidence for nonstoichiometry was found in the vicinity of LiMnPO{sub 4}. Attempts to create single phase solid solutions by heating mixtures of the two phases failed due to the thermal instability of Li{sub y}MnPO{sub 4}.
Date: April 7, 2009
Creator: Chen, Guoying & Richardson, Thomas J.
System: The UNT Digital Library
Proceedings of the meetings on the SSC between representatives of industry and high energy physics (open access)

Proceedings of the meetings on the SSC between representatives of industry and high energy physics

This report discusses the following topics: Alternate gradient synchrotron (Brookhaven); reliability and large storage ring (SLAC); and Fermilab and superconducting tevatron magnets.
Date: April 7, 1985
Creator: unknown
System: The UNT Digital Library
Production of e+e- Pairs Accompanied by Nuclear Dissociation in Ultra-peripheral Heavy Ion Collisions (open access)

Production of e+e- Pairs Accompanied by Nuclear Dissociation in Ultra-peripheral Heavy Ion Collisions

We present the first data on e{sup +}e{sup -} pair production accompanied by nuclear breakup in ultra-peripheral gold-gold collisions at a center of mass energy of 200 GeV per nucleon pair. The nuclear breakup requirement selects events at small impact parameters, where higher-order corrections to the pair production cross section should be enhanced. We compare the pair kinematic distributions with two calculations: one based on the equivalent photon approximation, and the other using lowest-order quantum electrodynamics (QED); the latter includes the photon virtuality. The cross section, pair mass, rapidity and angular distributions are in good agreement with both calculations. The pair transverse momentum, p{sub T}, spectrum agrees with the QED calculation, but not with the equivalent photon approach. We set limits on higher-order contributions to the cross section. The e{sup +} and e{sup -} p{sub T} spectra are similar, with no evidence for interference effects due to higher-order diagrams.
Date: April 7, 2004
Creator: Adams, J.; Adler, C.; Aggarwal, M. M.; Ahammed, Z.; Allgower, C.; Amonett, J. et al.
System: The UNT Digital Library
Impedance studies of the thin film LiMn2O4/electrolyteinterface (open access)

Impedance studies of the thin film LiMn2O4/electrolyteinterface

Room-temperature impedance measurements of a thin-film LiMn2O4/LiPF6-EC-DMC interface have been used to identify the spontaneous formation Li2Mn2O4 at the interface at room temperature at voltages of 3.7 and higher. The impedance of the LiMn2O4 films exhibited two time constants: at about 14 kHz and 60 to 200 Hz. The high frequency loop is dependent on film morphology and was attributed to the substrate/oxide interface. The low frequency behavior was dependent on both state-of-charge (SOC) and time at a given SOC. At full charge the impedance in this electrolyte was stable at room temperature over several days. At high lithium contents, film OCV and impedance tended to grow logarithmically with time, with lower rates for lower Mn3+ content in the film. The increased impedance was removed by oxidation of the film to 4.5V vs. Li/Li+. The observations are consistent with a reversible disproportionation of part of the LiMn2O4 into Li2Mn2O4 and a lithium-deficient spinel. With extended constant current cycling part of the Li2Mn2O4 degrades to the Mn2O3 and the process is no longer reversible.
Date: April 7, 2001
Creator: Striebel, Kathryn A.; Sakai, E. & Cairns, Elton J.
System: The UNT Digital Library
Simulating Electron Clouds in Heavy-Ion Accelerators (open access)

Simulating Electron Clouds in Heavy-Ion Accelerators

Contaminating clouds of electrons are a concern for most accelerators of positive-charged particles, but there are some unique aspects of heavy-ion accelerators for fusion and high-energy density physics which make modeling such clouds especially challenging. In particular, self-consistent electron and ion simulation is required, including a particle advance scheme which can follow electrons in regions where electrons are strongly-, weakly-, and un-magnetized. They describe their approach to such self-consistency, and in particular a scheme for interpolating between full-orbit (Boris) and drift-kinetic particle pushes that enables electron time steps long compared to the typical gyro period in the magnets. They present tests and applications: simulation of electron clouds produced by three different kinds of sources indicates the sensitivity of the cloud shape to the nature of the source; first-of-a-kind self-consistent simulation of electron-cloud experiments on the High-Current Experiment (HCX) at Lawrence Berkeley National Laboratory, in which the machine can be flooded with electrons released by impact of the ion beam and an end plate, demonstrate the ability to reproduce key features of the ion-beam phase space; and simulation of a two-stream instability of thin beams in a magnetic field demonstrates the ability of the large-timestep mover to accurately calculate the instability.
Date: April 7, 2005
Creator: Cohen, R. H.; Friedman, A.; Kireeff Covo, M.; Lund, S. M.; Molvik, A. W.; Bieniosek, F. M. et al.
System: The UNT Digital Library
Characterization of liquid phase epitaxial GaAs forblocked-impurity-band far-infrared detectors (open access)

Characterization of liquid phase epitaxial GaAs forblocked-impurity-band far-infrared detectors

GaAs Blocked-Impurity-Band (BIB) photoconductor detectors have the potential to become the most sensitive, low noise detectors in the far-infrared below 45.5 cm{sup -1} (220 {micro}m). We have studied the characteristics of liquid phase epitaxial GaAs films relevant to BIB production, including impurity band formation and the infrared absorption of the active section of the device. Knowledge of the far-infrared absorption spectrum as a function of donor concentration combined with variable temperature Hall effect and resistivity studies leads us to conclude that the optimal concentration for the absorbing layer of a GaAs BIB detector lies between 1 x 10{sup 15} and 6.7 x 10{sup 15} cm{sup -3}. At these concentrations there is significant wavefunction overlap which in turn leads to absorption beyond the 1s ground to 2p bound excited state transition of 35.5 cm{sup -1} (282 {micro}m). There still remains a gap between the upper edge of the donor band and the bottom of the conduction band, a necessity for proper BIB detector operation.
Date: April 7, 2004
Creator: Cardozo, B. L.; Reichertz, L. A.; Beeman, J. W. & Haller, E. E.
System: The UNT Digital Library
Potential VOC Deflagrations in a Vented TRU Drum (open access)

Potential VOC Deflagrations in a Vented TRU Drum

The objective of the analysis is to examine the potential for lid ejection from a vented transuranic (TRU) waste drum due to pressure buildup caused by the deflagration of hydrogen and volatile organic compounds (VOCs) inside the drum. In this analysis, the AICC pressure for a stoichiometric mixture of VOCs is calculated and then compared against the experimental peak pressure of stoichiometric combustion of propane and hexane in a combustion chamber. The experimental peak pressures of propane and hexane are about 12 percent lower than the calculated AICC pressure. Additional losses in the drum are calculated due to venting of the gases, drum bulging, waste compaction, and heat losses from the presence of waste in the drum. After accounting for these losses, the final pressures are compared to the minimum observed pressure that ejects the lid from a TRU drum. The ejection pressure of 105 psig is derived from data that was recorded for a series of tests where hydrogen-air mixtures were ignited inside sealed TRU drums. Since the calculated pressures are below the minimum lid ejection pressure, none of the VOCs and the hydrogen (up to 4 percent) mixtures present in the TRU waste drum is expected to cause …
Date: April 7, 2005
Creator: Mukesh, GUPTA
System: The UNT Digital Library
Risk-Based Management of Contaminated Groundwater: The Role of Geologic Heterogeneity, Exposure and Cancer Risk in Determining the Performance of Aquifer Remediation (open access)

Risk-Based Management of Contaminated Groundwater: The Role of Geologic Heterogeneity, Exposure and Cancer Risk in Determining the Performance of Aquifer Remediation

The effectiveness of aquifer remediation is typically expressed in terms of a reduction in contaminant concentrations relative to a regulated maximum contaminant level (MCL), and is usually confined by sparse monitoring data and/or simple model calculations. Here, the effectiveness of remediation is examined from a risk-based perspective that goes beyond the traditional MCL concept. A methodology is employed to evaluate the health risk to individuals exposed to contaminated household water that is produced from groundwater. This approach explicitly accounts for differences in risk arising from variability in individual physiology and water use, the uncertainty in estimating chemical carcinogenesis for different individuals, and the uncertainties and variability in contaminant concentrations within groundwater. A hypothetical contamination scenario is developed as a case study in a saturated, alluvial aquifer underlying a real Superfund site. A baseline (unremediated) human exposure and health risk scenario, as induced by contaminated groundwater pumped from this site, is predicted and compared with a similar estimate based upon pump-and-treat exposure intervention. The predicted reduction in risk in the remediation scenario is not an equitable one--that is, it is not uniform to all individuals within a population and varies according to the level of uncertainty in prediction. The importance of …
Date: April 7, 2000
Creator: Maxwell, R. M.; Carle, S. F. & Tompson, A. F. B.
System: The UNT Digital Library
Preparing the database for future CP violation measurements with B-mesons at e/sup +/e/sup -/ machines (open access)

Preparing the database for future CP violation measurements with B-mesons at e/sup +/e/sup -/ machines

We consider the contribution of e/sup /plus//e/sup /minus// machines to the measurement of CP violation in the B systems. Energy regions from the GAMMA(4S) to the Z/degree/ are considered, problems and prospects at each energy are reviewed.
Date: April 7, 1988
Creator: Byers, N.; Foley, K.; Goldberg, M.; Mistry, N & Shipsey, I.
System: The UNT Digital Library
Characterization of the Series 1000 Camera System (open access)

Characterization of the Series 1000 Camera System

The National Ignition Facility requires a compact network addressable scientific grade CCD camera for use in diagnostics ranging from streak cameras to gated x-ray imaging cameras. Due to the limited space inside the diagnostic, an analog and digital input/output option in the camera controller permits control of both the camera and the diagnostic by a single Ethernet link. The system consists of a Spectral Instruments Series 1000 camera, a PC104+ controller, and power supply. The 4k by 4k CCD camera has a dynamic range of 70 dB with less than 14 electron read noise at a 1MHz readout rate. The PC104+ controller includes 16 analog inputs, 4 analog outputs and 16 digital input/output lines for interfacing to diagnostic instrumentation. A description of the system and performance characterization is reported.
Date: April 7, 2004
Creator: Kimbrough, J. R.; Moody, J. D.; Bell, P. M. & Landen, O. L.
System: The UNT Digital Library
A turning point in the US Inertial Confinement Fusion Program (open access)

A turning point in the US Inertial Confinement Fusion Program

The goal of the US ICF Program is to obtain a high-yield (100 to 1000 MJ) and high-gain (about 100) thermonuclear fusion capability in the laboratory. It has long been recognized that before such a laboratory facility is constructed, it must be demonstrated that laboratory conditions can be created that will, with high probability, lead to high gain if a driver of sufficient energy is built and that such a facility can be built at reasonable cost. Thus, the two major aspects of the US program address target physics and driver development. Four main driver candidates are actively being pursued: solid state lasers (principally Nd:glass), KrF gas lasers, light ion beams (Li ions accelerated by ion diodes), and heavy ion beams )A /approximately/200, accelerated by linear induction accelerator). The target physics aspect of the program is further divided into indirect and direct drive targets. In indirect drive targets the driver beams are aimed at a material near the capsule to generate x-rays, which then are absorbed in the fusion capsule ablator to produce the implosion. In direct-drive targets, the driver beams are aimed at the surface of the capsule. However, even in this case it should be recognized that the …
Date: April 7, 1988
Creator: Hogan, W.J.
System: The UNT Digital Library
Development and Characterization of a High Performance Thin-Film Planar Solid-Oxide Fuel Cell Stack (open access)

Development and Characterization of a High Performance Thin-Film Planar Solid-Oxide Fuel Cell Stack

A planar solid oxide fuel cell (SOFC) was fabricated using a tape-cast Ni/yttria-stabilized zirconia (YSZ) anode support, a YSZ thin film electrolyte, and a composite cathode of YSZ and (La{sub 0.85}Sr{sup 0.14}){sub 0.98}MnO{sub 3} (LSM). Using pure hydrogen as the fuel gas, a three cell stack with a cross-flow design and external manifolds produced peak power densities of 0.85 W/cm{sup 2} and 0.41 W/cm{sup 2} at 800 C and 700 C, respectively. Using wet methane as the fuel gas, the stack produced a peak power density of 0.22 W/cm{sup 2} at 700 C. Individual cells in the stack showed identical current-voltage (I -V) characteristics. Stack lifetime was limited because of degradation of the cells from oxidation products coming from the metallic interconnect used.
Date: April 7, 2004
Creator: Chung, Brandon W.; Chervin, Christopher N; Haslam, Jeffrey J.; Pham, Ai-Quoc & Glass, Robert S.
System: The UNT Digital Library
The Subsurface Flow and Transport Experimental Laboratory: A New Department of Energy Users Facility for Intermediate-Scale Experimentation. (open access)

The Subsurface Flow and Transport Experimental Laboratory: A New Department of Energy Users Facility for Intermediate-Scale Experimentation.

Intermediate-scale experiments (ISEs) for flow and transport are a valuable tool for simulating subsurface features and conditions encountered in the field at government and private sites. ISEs offer the ability to study, under controlled laboratory conditions, complicated processes characteristic of mixed wastes and heterogeneous subsurface environments, in multiple dimensions and at different scales. ISEs may, therefore, result in major cost savings if employed prior to field studies. A distinct advantage of ISEs is that researchers can design physical and/or chemical heterogeneities in the porous media matrix that better approximate natural field conditions and therefore address research questions that contain the additional complexity of processes often encountered in the natural environment. A new Subsurface Flow and Transport Experimental Laboratory (SFTEL) has been developed for ISE users in the Environmental Molecular Sciences Laboratory (EMSL) at Pacific Northwest National Laboratory (PNNL). The SFTEL offers a variety of columns and flow cells, a new state-of-the-art dual-energy gamma system, a fully automated saturation-pressure apparatus, and analytical equipment for sample processing. The new facility, including qualified staff, is available for scientists interested in collaboration on conducting high-quality flow and transport experiments, including contaminant remediation. Close linkages exist between the SFTEL and numerical modelers to aid in …
Date: April 7, 2004
Creator: Oostrom, Mart; Wietsma, Thomas W.; Foster, Nancy S. & Ramirez, J. A.
System: The UNT Digital Library
STATISTICAL SAMPLING FOR IN-SERVICE INSPECTION OF LIQUID WASTE TANKS AT THE SAVANNAH RIVER SITE (open access)

STATISTICAL SAMPLING FOR IN-SERVICE INSPECTION OF LIQUID WASTE TANKS AT THE SAVANNAH RIVER SITE

Savannah River Remediation, LLC (SRR) is implementing a statistical sampling strategy for In-Service Inspection (ISI) of Liquid Waste (LW) Tanks at the United States Department of Energy's Savannah River Site (SRS) in Aiken, South Carolina. As a component of SRS's corrosion control program, the ISI program assesses tank wall structural integrity through the use of ultrasonic testing (UT). The statistical strategy for ISI is based on the random sampling of a number of vertically oriented unit areas, called strips, within each tank. The number of strips to inspect was determined so as to attain, over time, a high probability of observing at least one of the worst 5% in terms of pitting and corrosion across all tanks. The probability estimation to determine the number of strips to inspect was performed using the hypergeometric distribution. Statistical tolerance limits for pit depth and corrosion rates were calculated by fitting the lognormal distribution to the data. In addition to the strip sampling strategy, a single strip within each tank was identified to serve as the baseline for a longitudinal assessment of the tank safe operational life. The statistical sampling strategy enables the ISI program to develop individual profiles of LW tank wall structural …
Date: April 7, 2011
Creator: Harris, S. & Baxter, L.
System: The UNT Digital Library
Breast Cancer Cells in Three-dimensional Culture Display an Enhanced Radioresponse after Coordinate Targeting of Integrin ?5?1 and Fibronectin (open access)

Breast Cancer Cells in Three-dimensional Culture Display an Enhanced Radioresponse after Coordinate Targeting of Integrin ?5?1 and Fibronectin

Tactics to selectively enhance cancer radioresponse are of great interest. Cancer cells actively elaborate and remodel their extracellular matrix (ECM) to aid in survival and progression. Previous work has shown that {beta}1-integrin inhibitory antibodies can enhance the growth-inhibitory and apoptotic responses of human breast cancer cell lines to ionizing radiation, either when cells are cultured in three-dimensional laminin-rich ECM (3D lrECM) or grown as xenografts in mice. Here, we show that a specific {alpha} heterodimer of {beta}1-integrin preferentially mediates a prosurvival signal in human breast cancer cells that can be specifically targeted for therapy. 3D lrECM culture conditions were used to compare {alpha}-integrin heterodimer expression in malignant and nonmalignant cell lines. Under these conditions, we found that expression of {alpha}5{beta}1-integrin was upregulated in malignant cells compared with nonmalignant breast cells. Similarly, we found that normal and oncofetal splice variants of fibronectin, the primary ECM ligand of {alpha}5{beta}1-integrin, were also strikingly upregulated in malignant cell lines compared with nonmalignant acini. Cell treatment with a peptide that disrupts the interactions of {alpha}5{beta}1-integrin with fibronectin promoted apoptosis in malignant cells and further heightened the apoptotic effects of radiation. In support of these results, an analysis of gene expression array data from breast cancer …
Date: April 7, 2010
Creator: Nam, Jin-Min; Onodera, Yasuhito; Bissell, Mina J & Park, Catherine C
System: The UNT Digital Library