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Buus S.,Copenhagen University | Rockberg J.,Albanova University Center | Forsstrom B.,Albanova University Center | Nilsson P.,KTH Royal Institute of Technology | And 3 more authors.
Molecular and Cellular Proteomics | Year: 2012

Antibodies empower numerous important scientific, clinical, diagnostic, and industrial applications. Ideally, the epitope(s) targeted by an antibody should be identified and characterized, thereby establishing antibody reactivity, highlighting possible cross-reactivities, and perhaps even warning against unwanted (e.g. autoimmune) reactivities. Antibodies target proteins as either conformational or linear epitopes. The latter are typically probed with peptides, but the cost of peptide screening programs tends to prohibit comprehensive specificity analysis. To perform high-throughput, high-resolution mapping of linear antibody epitopes, we have used ultrahigh-density peptide microarrays generating several hundred thousand different peptides per array. Using exhaustive length and substitution analysis, we have successfully examined the specificity of a panel of polyclonal antibodies raised against linear epitopes of the human proteome and obtained very detailed descriptions of the involved specificities. The epitopes identified ranged from 4 to 12 amino acids in size. In general, the antibodies were of exquisite specificity, frequently disallowing even single conservative substitutions. In several cases, multiple distinct epitopes could be identified for the same target protein, suggesting an efficient approach to the generation of paired antibodies. Two alternative epitope mapping approaches identified similar, although not necessarily identical, epitopes. These results show that ultrahigh-density peptide microarrays can be used for linear epitope mapping. With an upper theoretical limit of 2,000,000 individual peptides per array, these peptide microarrays may even be used for a systematic validation of antibodies at the proteomic level. © 2012 by The American Society for Biochemistry and Molecular Biology, Inc. Source

Phillips P.J.,U.S. National Institute of Standards and Technology | Scruggs W.T.,SAIC | O'Toole A.J.,University of Texas at Dallas | Flynn P.J.,University of Notre Dame | And 3 more authors.
IEEE Transactions on Pattern Analysis and Machine Intelligence | Year: 2010

This paper describes the large-scale experimental results from the Face Recognition Vendor Test (FRVT) 2006 and the Iris Challenge Evaluation (ICE) 2006. The FRVT 2006 looked at recognition from high-resolution still frontal face images and 3D face images, and measured performance for still frontal face images taken under controlled and uncontrolled illumination. The ICE 2006 evaluation reported verification performance for both left and right irises. The images in the ICE 2006 intentionally represent a broader range of quality than the ICE 2006 sensor would normally acquire. This includes images that did not pass the quality control software embedded in the sensor. The FRVT 2006 results from controlled still and 3D images document at least an order-of-magnitude improvement in recognition performance over the FRVT 2002. The FRVT 2006 and the ICE 2006 compared recognition performance from high-resolution still frontal face images, 3D face images, and the single-iris images. On the FRVT 2006 and the ICE 2006 data sets, recognition performance was comparable for high-resolution frontal face, 3D face, and the iris images. In an experiment comparing human and algorithms on matching face identity across changes in illumination on frontal face images, the best performing algorithms were more accurate than humans on unfamiliar faces. © 2006 IEEE. Source

Coombs D.M.,CSA Engineering Inc. | Goodding J.C.,CSA Engineering Inc. | Babuska V.,Sandia National Laboratories | Ardelean E.V.,Schafer Corporation | And 2 more authors.
Journal of Spacecraft and Rockets | Year: 2011

Power and signal cable harnesses on spacecraft are often at 10% of the total mass and can be as much as 30%. These cable harnesses can impact the structural dynamics of spacecraft significantly, specifically by damping the response. Past efforts have looked at how to calculate cable properties and the validation of these cable models on one-dimensional beam structures with uniform cable lengths. This paper looks at how to extend that process to two-dimensional spacecraftlike panels with nonuniform cable lengths. A shear beam model is used for cable properties. Two methods of calculating the tiedown stiffness are compared. Of particular interestis whetherornot handbooks of cable properties canbe created ahead of time and applied with confidence. There are three frequency bands inwhich cable effects canbe described. Before any cables become resonant, the cable effects are dominated by mass and static stiffness. After all the cables become resonant, the effect is dominated by increased damping in the structure. In between these two frequency cutoff points, there is a transition zone. The dynamic cable modeling methodis validated as a distinct improvement over the lumped-mass characterization of cables commonly used today. Copyright © 2011 by the American Institute of Aeronautics and Astronautics,. Source

Goodding J.C.,CSA Engineering Inc. | Ardelean E.V.,Schafer Corporation | Babuska V.,Sandia National Laboratories | Robertson L.M.,U.S. Air force | Lane S.A.,U.S. Air force
Journal of Spacecraft and Rockets | Year: 2011

Signal and electrical power cables pose unique challenges to spacecraft structural design and are often poorly modeled or even neglected. The objective of this research was to develop test methods and analysis techniques to accurately model cable-loaded spacecraft, using linear finite element models. Test methods were developed to characterize cable extensional and bending properties when subjected to low-level lateral dynamic loads. Timoshenko beam theory, including shear and bending, was used to model cable lateral dynamics, and the model formulation applicability was validated through experiment. An algorithm was developed to estimate cable area moment of inertia and shear area factor, shear modulus product, from a single driving point mobility function. Test methods and the parameter estimation algorithm were validated, using metallic rod test specimens. Experiments were performed on cables of differing constructions and spans, to develop a database for finite element modeling validation experiments. Copyright © 2011 by the American Institute of Aeronautics and Astronautics. Source

Slater J.M.,Schafer Corporation | Edwards B.,Lincoln Laboratory
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010

This paper discusses methods for characterization of high power lasers. Specifically, these methods have been developed for the High Energy Laser Joint Technology Office and used for independent, government-sponsored testing in the 25 and 100 kW phases of the Joint High Power Solid State Laser program. Primarily this paper addresses measurement of power and beam quality. © 2010 Copyright SPIE - The International Society for Optical Engineering. Source

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