1,918 research outputs found

    The Hilltop 9-26-1975

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    This document created through a generous donation of Mr. Paul Cottonhttps://dh.howard.edu/hilltop_197080/1141/thumbnail.jp

    Spaceborne sensors (1983-2000 AD): A forecast of technology

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    A technical review and forecast of space technology as it applies to spaceborne sensors for future NASA missions is presented. A format for categorization of sensor systems covering the entire electromagnetic spectrum, including particles and fields is developed. Major generic sensor systems are related to their subsystems, components, and to basic research and development. General supporting technologies such as cryogenics, optical design, and data processing electronics are addressed where appropriate. The dependence of many classes of instruments on common components, basic R&D and support technologies is also illustrated. A forecast of important system designs and instrument and component performance parameters is provided for the 1983-2000 AD time frame. Some insight into the scientific and applications capabilities and goals of the sensor systems is also given

    Simulation verification techniques study. Subsystem simulation validation techniques

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    Techniques for validation of software modules which simulate spacecraft onboard systems are discussed. An overview of the simulation software hierarchy for a shuttle mission simulator is provided. A set of guidelines for the identification of subsystem/module performance parameters and critical performance parameters are presented. Various sources of reference data to serve as standards of performance for simulation validation are identified. Environment, crew station, vehicle configuration, and vehicle dynamics simulation software are briefly discussed from the point of view of their interfaces with subsystem simulation modules. A detailed presentation of results in the area of vehicle subsystems simulation modules is included. A list of references, conclusions and recommendations are also given

    Abbreviations and acronyms

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    This booklet provides a partial list of acronyms, abbreviations, and other short word forms, including their definitions, used in documents at the Goddard Space Flight Center (GSFC). This list does not preclude the use of other short forms of less general usage, as long as these short forms are identified the first time they appear in a document and are defined in a glossary in the document in which they are used. This document supplements information in the GSFC Scientific and Technical Information Handbook (GHB 2200.2/April 1989). It is not intended to contain all short word forms used in GSFC documents; however, it was compiled of actual short forms used in recent GSFC documents. The entries are listed first, alphabetically by the short form, and then again alphabetically by definition

    Soluble Antigen Arrays utilize molecular and physical features to suppress Experimental Autoimmune Encephalomyelitis

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    Blockade of immune cell adhesion during antigen recognition may suppress the inflammatory immune response in autoimmune diseases. Employing a novel N-oxime chemistry, Soluble Antigen Arrays (SAgAs) were synthesized to simultaneously display intracellular cell-adhesion molecule-1 (ICAM-1) inhibitor and antigen. Hyaluronic acid (HA) was used as a backbone and two peptides were grafted, an ICAM-1 inhibitor (LABL) derived from αL-integrin and an encephalitogenic epitope of proteolipid protein (PLP). Mice with experimental autoimmune encephalomyelitis (EAE) that received subcutaneous (s.c.) injections of SAgAs displaying both peptides showed significantly lower clinical disease scores and incidence, as well as better body weight maintenance than those treated with HA polymer alone. Multivalent presentation of cell-adhesion inhibitor (LABL) alone or antigen (PLP) alone was also evaluated. Treatment with hyaluronic acid grafted with only PLP antigen or only LABL peptide did not provide significant disease suppression and, in the case of LABL, actually exacerbated the disease. When hyaluronic acid was replaced with a PLGA nanoparticle displaying grafted LABL and PLP (NP-ArrayLABL-PLP), an analogous treatment strategy with the NP-Array¬LABL-PLP did not provide significant EAE suppression. Next, the effect of SAgA molecular weight and cell-adhesion molecule target were evaluated. SAgAs with inhibitors targeting intracellular cell-adhesion molecule-1 (ICAM-1) or its ligand leukocyte-associated function antigen-1 (LFA-1) were equally effective. Also, the disease onset was delayed and severity was significantly reduced when the molecular weight of the SAgA was decreased. Animal imaging suggested that the smaller SAgA drained from the injection site more quickly than the larger SAgA, which may suggest enhanced transit to the regional lymphatics. Analysis of the cytokine production profiles of all treatments demonstrated that reducing SAgA size also provided the largest change in inflammatory cytokine response. SAgA performance, therefore, depended on lymphatic drainage as dictated by size, as well as molecular signaling resulting from co-grafting cell-adhesion inhibitor and antigen. Future research should attempt to correlate SAgA transport with efficacy and explore the effect of grafting different inhibitors or activators of co-stimulation

    Structured layout design

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