Rubin R.L.,University of New Mexico |
Wall D.,Voss Scientific, LLC |
Konstantinov K.N.,University of New Mexico
Biosensors and Bioelectronics | Year: 2014
Measurement of serum autoantibody is a critical tool in the diagnosis and management of autoimmune diseases. However, rapid and convenient methods at the point-of care have not been achieved in large part because any one antibody species is a heterogeneous and miniscule fraction of the total serum immunoglobulin displaying identical properties other than its antigen-binding specificity. The present system addresses these challenges by vacuum-mediated transport of diluted serum through an antigen-coated porous membrane. To measure anti-DNA autoantibodies, native DNA was immobilized into a poly(vinylidene fluoride) membrane pre-coated with a synthetic phenylalanine/lysine co-polymer. Flow-through of primary and peroxidase-conjugated secondary antibodies over the course of 3. min enhanced productive antibody-antigen interactions by bringing the reactants into close mutual proximity. Signal was quantified electrochemically during the enzymatic conversion of the tetramethylbenzidine substrate to a charge-transfer complex. The electrochemical signals generated by sera from patients with systemic lupus erythematosus using this device showed good quantitative correlation with a standard enzyme-linked immunosorbent assay and displayed similar detection limits. Inter- and intra-assay variability and electrode uniformity were favorable as was a two-month test of the stability of the DNA-coated membrane. While refining the fluidics requirements of this biosensor will be needed, its capacity to quantify over the course of 30. min anti-DNA antibodies in fresh human serum without background reactivity of normal serum makes this a promising technology as a point-of care device of clinical utility. © 2013 Elsevier B.V. Source
Agency: Department of Defense | Branch: Air Force | Program: SBIR | Phase: Phase II | Award Amount: 2.00M | Year: 2012
ABSTRACT: Voss Scientific proposes to develop an Automated Susceptibility Test Assembly (ASTA) which will be capable of efficiently determining preferred electromagnetic (EM) source waveforms for inducing effects in target electronic systems. This novel adaptive approach will potentially discover unique waveforms that substantially reduce the intensity of the microwave illumination required to cause upset in electronic systems. The potential benefits of this technique include smaller High Power Microwave (HPM) sources, longer stand-off ranges, more reliable results, improved hardening methods, and reduced collateral effects on unintended targets. By reducing the required intensity, missions scenarios which were previously impractical will be within reach. ASTA system utilizes a fully integrated, computer controlled hardware set, highly agile in both the frequency and time domains, to generate the irradiating EM fields. The hardware is controlled by an intelligent test automation application, which employs a novel rule-based execution scheme that combines both traditional test matrices and optimization algorithms. A broad suite of diagnostics will be implemented for damage assessment, including sensors, custom software resident on the asset, remote EM emission sensing, and asset specific diagnostic boards. The Phase II work will conclude with a demonstration of an automated test at L-band on multiple versions of fully instrumented assets. BENEFIT: The capability to explore the RF illumination parameter space with both increased breadth and detail using an automated system will provide substantial benefit to both the military HPM community and the commercial electronics industry. The primary benefit to the military is the capability to identify and exploit susceptibilities, allowing performance of previously impossible HPM and EW missions. ASTA testing can also provide the information needed to improve RF shielding and hardening for US systems, providing an increased confidence level on battlefield operations. In addition, the customized waveform produced by the system is unique to the target asset class. This greatly reduces the probability of undesired collateral effects on unintended targets. The commercial EMI industry will also benefit from improved hardening capabilities provided by this approach and by the general test automation methodology. The improved efficiency and reduced manpower required for susceptibility and EMI compliance tests will be an advantage to both military and commercial users.
Agency: Department of Defense | Branch: Defense Advanced Research Projects Agency | Program: SBIR | Phase: Phase II | Award Amount: 1.50M | Year: 2015
Efficient computational analysis of systems exhibiting complex plasma phenomena, including non-neutral kinetic, fluid behaviors with radiation transport are critical to many DoD missions. Examples of these systems include plasma thrusters, hypersonic vehicles, radiation effects simulations, RF sources, and compact neutron sources. Current simulation tools rely heavily on magneto-hydrodynamic (MHD) models for these systems, which ignore important kinetic effects. Additionally, available commercial codes have not exhibited scaling to massively-parallel CPU/GPU architectures. The goal is to have a single, fast-running simulation tool that dynamically spans both MHD and kinetic regimes, correctly resolving spatial and temporal features. Voss Scientific proposes to develop a new parallel, implicit EM, FDTD PIC code with the following features: two-level domain decomposition using MPI, and CPU/GPU parallelization at critical sections. This approach enables rapid deployment from validated and verified computational physics models and algorithms. The new code will deploy algorithms for dynamic switching between different plasma model descriptions (e.g., fluid to kinetic), adaptive and dynamic mesh refinement. New algorithms with automatic transitioning between the plasma models will be implemented and made robust for general use. The new code will enable accurate design simulations for a wide variety of DoD missions.
Agency: Department of Defense | Branch: Air Force | Program: STTR | Phase: Phase II | Award Amount: 750.00K | Year: 2014
ABSTRACT: Strong coupling in ionized plasmas occurs when inter-particle interactions result in correlation energies that are comparable to the mean kinetic energy of the thermal motion of individual particles. Strongly coupled plasmas are known to be present in a number of physical systems including ultra-cold plasmas created in the laboratory and present in the ionosphere, explosive gases associated with conventional munitions, and extreme conditions associated with high-energy ultrafast laser interactions with matter. The use of the electromagnetic (EM) particle-in-cell methodology (PIC) for modeling strongly coupled plasmas is an accurate model when the inter-ion spacing is resolved. The EM PIC approach offers features that complement existing models of strongly coupled plasmas and should give computational speeds comparable to or greater than other computational methods. A framework for integrating newly developed advanced algorithms into a simulation code capable of addressing plasma physics research topics that are not treatable with currently available simulation codes. Under a Phase II award, a complete computer code deployable on conventional parallel computer systems will be developed and validated against theoretical models. BENEFIT: Non-equilibrium plasmas are playing an increasingly important role in a number of Air Force high technology situations and strongly coupled plasma conditions occur in many of these technologies. For example, creation and evolution of non-equilibrium plasmas and the management of energy flow in high energy density situations (such as directed energy weapons) is integral to Air Force programs. Large-scale numerical simulation codes are required for the laser and high power microwave analysis of non-equilibrium coupled plasmas. However, the analysis of strongly coupled classical plasmas in the electromagnetic regime is currently limited to idealized equilibrium models. The software developed under this Phase II effort represents a significant new technique to analyze coupled plasma conditions, synergistic with Air Force technology programs. Potential commercial applications for this simulation tool include university research groups, various high-technology industries supporting Air Force research and development programs, as well as DoD and DoE research institutions. Applications for this simulation tool are wide ranging and include plasma reactor modeling, extreme states of matter, ionospheric communications, and quantum computing research.
Agency: Department of Defense | Branch: Air Force | Program: STTR | Phase: Phase I | Award Amount: 100.00K | Year: 2010
Military applications for the use of directed electromagnetic energy, which include high power microwave (HPM), seek to disrupt electronic systems by exploiting non-linearity in semiconductors. While current mode second breakdown is a thermal non-linearity often exploited, it has been demonstrated that a broad class of semiconductors have more subtle non-linearities that can be utilized to induce upset. For example, “designer waveforms” tailored to specific classes of semiconductors can induce sub-harmonics that can be particularly effective on digital timing circuits. Once induced, these sub-harmonics result in digital upset and it is necessary to recycle power to restore normal circuit operation. The proposed task is to demonstrate the feasibility of modeling the effects of RF/HPM fields on circuits containing Voltage Controlled Oscillators (VCOs). The Phase I task will incorporate and improve current models of the effects of electrical transients on VCOs as well as recent work on the development of a probabilistic electromagnetic coupling model. In addition tests will be carried out on representative VCO circuits in order to validate the model. The specialized waveforms developed during the Phase I and associated Phase II work will enable entirely new classes of missions for HPM and electronic warfare (EW) military applications. BENEFIT: The development of a modeling capability for HPM induced upset of Voltage Controlled Oscillators would have an immediate effect on the ability to predict upset of digital circuits. The resulting models would assist in the development of end-to-end HPM effects codes and the development of waveforms targeted at specific types of equipment. Commercial applications would include modeling of RF susceptibilities, support of EMC/EMI testing of digital equipment, and possible inclusion into design standards.