Draft versus finished sequence data for DNA and protein diagnostic signature development (open access)

Draft versus finished sequence data for DNA and protein diagnostic signature development

Sequencing pathogen genomes is costly, demanding careful allocation of limited sequencing resources. We built a computational Sequencing Analysis Pipeline (SAP) to guide decisions regarding the amount of genomic sequencing necessary to develop high-quality diagnostic DNA and protein signatures. SAP uses simulations to estimate the number of target genomes and close phylogenetic relatives (near neighbors, or NNs) to sequence. We use SAP to assess whether draft data is sufficient or finished sequencing is required using Marburg and variola virus sequences. Simulations indicate that intermediate to high quality draft with error rates of 10{sup -3}-10{sup -5} ({approx} 8x coverage) of target organisms is suitable for DNA signature prediction. Low quality draft with error rates of {approx} 1% (3x to 6x coverage) of target isolates is inadequate for DNA signature prediction, although low quality draft of NNs is sufficient, as long as the target genomes are of high quality. For protein signature prediction, sequencing errors in target genomes substantially reduce the detection of amino acid sequence conservation, even if the draft is of high quality. In summary, high quality draft of target and low quality draft of NNs appears to be a cost-effective investment for DNA signature prediction, but may lead to underestimation …
Date: October 29, 2004
Creator: Gardner, S N; Lam, M W; Smith, J R; Torres, C L & Slezak, T R
System: The UNT Digital Library
Modeling of Long-Range Atmospheric Lasercom Links Between Static and Mobile Platforms (open access)

Modeling of Long-Range Atmospheric Lasercom Links Between Static and Mobile Platforms

We describe modeling and simulation of long-range terrestrial laser communications links between static and mobile platforms. Atmospheric turbulence modeling, along with pointing, tracking and acquisition models are combined to provide an overall capability to estimate communications link performance.
Date: July 29, 2003
Creator: Scharlemann, E T; Breitfeller, E F; Henderson, J R; Kallman, J S; Morris, J R & Ruggiero, A J
System: The UNT Digital Library
China Spallation Neutron Source Design (open access)

China Spallation Neutron Source Design

The China Spallation Neutron Source (CSNS) is an accelerator-based high-power project currently in preparation under the direction of the Chinese Academy of Sciences (CAS). The complex is based on an H- linear accelerator, a rapid cycling proton synchrotron accelerating the beam to 1.6 GeV, a solid tungsten target station, and five initial instruments for spallation neutron applications. The facility will operate at 25 Hz repetition rate with a phase-I beam power of about 120 kW. The major challenge is to build a robust and reliable user's facility with upgrade potential at a fractional of ''world standard'' cost.
Date: January 29, 2007
Creator: Wei, J.
System: The UNT Digital Library
Hadron Spectroscopy and Structure from AdS/CFT (open access)

Hadron Spectroscopy and Structure from AdS/CFT

The AdS/CFT correspondence between conformal field theory and string states in an extended space-time has provided new insights into not only hadron spectra, but also their light-front wavefunctions. We show that there is an exact correspondence between the fifth-dimensional coordinate of anti-de Sitter space z and a specific impact variable {zeta} which measures the separation of the constituents within the hadron in ordinary space-time. This connection allows one to predict the form of the light-front wavefunctions of mesons and baryons, the fundamental entities which encode hadron properties and scattering amplitudes. A new relativistic Schroedinger light-front equation is found which reproduces the results obtained using the fifth-dimensional theory. Since they are complete and orthonormal, the AdS/CFT model wavefunctions can be used as an initial ansatz for a variational treatment or as a basis for the diagonalization of the light-front QCD Hamiltonian. A number of applications of light-front wavefunctions are also discussed.
Date: September 29, 2006
Creator: Brodsky, Stanley J.
System: The UNT Digital Library
Computational approaches for identification of conserved/unique binding pockets in the A chain of ricin (open access)

Computational approaches for identification of conserved/unique binding pockets in the A chain of ricin

Specific and sensitive ligand-based protein detection assays that employ antibodies or small molecules such as peptides, aptamers, or other small molecules require that the corresponding surface region of the protein be accessible and that there be minimal cross-reactivity with non-target proteins. To reduce the time and cost of laboratory screening efforts for diagnostic reagents, we developed new methods for evaluating and selecting protein surface regions for ligand targeting. We devised combined structure- and sequence-based methods for identifying 3D epitopes and binding pockets on the surface of the A chain of ricin that are conserved with respect to a set of ricin A chains and unique with respect to other proteins. We (1) used structure alignment software to detect structural deviations and extracted from this analysis the residue-residue correspondence, (2) devised a method to compare corresponding residues across sets of ricin structures and structures of closely related proteins, (3) devised a sequence-based approach to determine residue infrequency in local sequence context, and (4) modified a pocket-finding algorithm to identify surface crevices in close proximity to residues determined to be conserved/unique based on our structure- and sequence-based methods. In applying this combined informatics approach to ricin A we identified a conserved/unique pocket …
Date: January 29, 2005
Creator: Ecale Zhou, C L; Zemla, A T; Roe, D; Young, M; Lam, M; Schoeniger, J et al.
System: The UNT Digital Library
Rap1 integrates tissue polarity, lumen formation, and tumorigenicpotential in human breast epithelial cells (open access)

Rap1 integrates tissue polarity, lumen formation, and tumorigenicpotential in human breast epithelial cells

Maintenance of apico-basal polarity in normal breast epithelial acini requires a balance between cell proliferation, cell death, and proper cell-cell and cell-extracellular matrix signaling. Aberrations in any of these processes can disrupt tissue architecture and initiate tumor formation. Here we show that the small GTPase Rap1 is a crucial element in organizing acinar structure and inducing lumen formation. Rap1 activity in malignant HMT-3522 T4-2 cells is appreciably higher than in S1 cells, their non-malignant counterparts. Expression of dominant-negative Rap1 resulted in phenotypic reversion of T4-2 cells, led to formation of acinar structures with correct apico-basal polarity, and dramatically reduced tumor incidence despite the persistence of genomic abnormalities. The resulting acini contained prominent central lumina not observed when other reverting agents were used. Conversely, expression of dominant-active Rap1 in T4-2 cells inhibited phenotypic reversion and led to increased invasiveness and tumorigenicity. Thus, Rap1 acts as a central regulator of breast architecture, with normal levels of activation instructing apical polarity during acinar morphogenesis, and increased activation inducing tumor formation and progression to malignancy.
Date: September 29, 2006
Creator: Itoh, Masahiko; Nelson, Celeste M.; Myers, Connie A. & Bissell,Mina J.
System: The UNT Digital Library
Femtoscopy in Relativistic Heavy Ion Collisions (open access)

Femtoscopy in Relativistic Heavy Ion Collisions

Analyses of two-particle correlations have provided the chief means for determining spatio-temporal characteristics of relativistic heavy ion collisions. We discuss the theoretical formalism behind these studies and the experimental methods used in carrying them out. Recent results from RHIC are put into context in a systematic review of correlation measurements performed over the past two decades. The current understanding of these results are discussed in terms of model comparisons and overall trends.
Date: July 29, 2005
Creator: Lisa, M; Pratt, S; Soltz, R A & Wiedemann, U
System: The UNT Digital Library
Proceedings of the Columbia River Estuary Conference on Ecosystem Restoration, April 29-30, 2008, Astoria, Oregon. (open access)

Proceedings of the Columbia River Estuary Conference on Ecosystem Restoration, April 29-30, 2008, Astoria, Oregon.

The 2008 Columbia River Estuary Conference was held at the Liberty Theater in Astoria, Oregon, on April 19-20. The conference theme was ecosystem restoration. The purpose of the conference was to exchange data and information among researchers, policy-makers, and the public, i.e., interrelate science with management. Conference organizers invited presentations synthesizing material on Restoration Planning and Implementation (Session 1), Research to Reduce Restoration Uncertainties (Session 2), Wetlands and Flood Management (Session 3), Action Effectiveness Monitoring (Session 4), and Management Perspectives (Session 5). A series of three plenary talks opened the conference. Facilitated speaker and audience discussion periods were held at the end of each session. Contributed posters conveyed additional data and information. These proceedings include abstracts and notes documenting questions from the audience and clarifying answers from the presenter for each talk. The proceedings also document key points from the discussion periods at the end of each session. The conference program is outlined in the agenda section. Speaker biographies are presented in Appendix A. Poster titles and authors are listed in Appendix B. A list of conference attendees is contained in Appendix C. A compact disk, attached to the back cover, contains material in hypertext-markup-language from the conference website (http://cerc.labworks.org/) …
Date: September 29, 2008
Creator: Johnson, Gary E. & Sutherland, G. Bruce
System: The UNT Digital Library