127 research outputs found

    An Overview of Lessons Learned from Sonic-Boom Flight Research Projects Conducted by NASA Armstrong Flight Research Center

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    This presentation describes the planning and executing of large scale sonic-boom acoustics tests as a part of LBFD testing with the goal to give the future teams the road-map for how to efficiently and effectively plan and execute these types of tests

    An Overview of Lessons Learned from Sonic-boom Flight Research Projects Conducted by NASA Armstrong Flight Research Center

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    Over the course of four years, a team of aerospace engineers at the National Aeronautics and Space Administration Armstrong Flight Research Center completed four projects, each with the objective to research sonic-boom signatures from a ground-and building-level perspective. The relatively compressed timeline of these projects resulted in many lessons learned. With each successive project, these lessons have been more relied upon and referenced. This paper provides a high-level overview of the teams relevant lessons learned and the importance of these lessons for future projects

    Efficacy and Safety Comparison Between Suberoylanilide Hydroxamic Acid and Mitomycin C in Reducing the Risk of Corneal Haze After PRK Treatment In Vivo

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    PURPOSE: This study compared the efficacy and safety of suberoylanilide hydroxamic acid (SAHA) and mitomycin C (MMC) up to 4 months in the prevention of corneal haze induced by photorefractive keratectomy (PRK) in rabbits in vivo. METHODS: Corneal haze in rabbits was produced with −9.00 diopter PRK. A single application of SAHA (25 μM) or MMC (0.02%) was applied topically immediately after PRK. Effects of the two drugs were analyzed by slit-lamp microscope, specular microscope, TUNEL assay, and immunofluorescence. RESULTS: Single topical adjunct use of SAHA (25 μM) or MMC (0.02%) after PRK attenuated more than 95% corneal haze and myofibroblast formation (P \u3c .001). SAHA did not reduce keratocyte density, cause keratocyte apoptosis, or increase immune cell infiltration compared to MMC (P \u3c .01 or .001). Furthermore, SAHA dosing did not compromise corneal endothelial phenotype, density, or function in rabbit eyes, whereas MMC application did (P \u3c .01 or .001). CONCLUSIONS: SAHA and MMC significantly decreased corneal haze after PRK in rabbits in vivo. SAHA exhibited significantly reduced short- and long-term damage to the corneal endothelium compared to MMC in rabbits. SAHA is an effective and potentially safer alternative to MMC for the prevention of corneal haze after PRK. Clinical trials are warranted

    Receptors and Other Signaling Proteins Required for Serotonin Control of Locomotion in Caenorhabditis elegans

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    A better understanding of the molecular mechanisms of signaling by the neurotransmitter serotonin is required to assess the hypothesis that defects in serotonin signaling underlie depression in humans. Caenorhabditis elegans uses serotonin as a neurotransmitter to regulate locomotion, providing a genetic system to analyze serotonin signaling. From large-scale genetic screens we identified 36 mutants of C. elegans in which serotonin fails to have its normal effect of slowing locomotion, and we molecularly identified eight genes affected by 19 of the mutations. Two of the genes encode the serotonin-gated ion channel MOD-1 and the G-protein-coupled serotonin receptor SER-4. mod-1 is expressed in the neurons and muscles that directly control locomotion, while ser-4 is expressed in an almost entirely non-overlapping set of sensory and interneurons. The cells expressing the two receptors are largely not direct postsynaptic targets of serotonergic neurons. We analyzed animals lacking or overexpressing the receptors in various combinations using several assays for serotonin response. We found that the two receptors act in parallel to affect locomotion. Our results show that serotonin functions as an extrasynaptic signal that independently activates multiple receptors at a distance from its release sites and identify at least six additional proteins that appear to act with serotonin receptors to mediate serotonin response.National Institutes of Health (U.S.) (Grant GM24663

    Vorinostat: A Potent Agent to Prevent and Treat Laser-Induced Corneal Haze

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    PURPOSE—This study investigated the efficacy and safety of vorinostat, a deacetylase (HDAC) inhibitor, in the treatment of laser-induced corneal haze following photorefractive keratectomy (PRK) in rabbits in vivo and transforming growth factor beta 1 (TGFβ1) -induced corneal fibrosis in vitro. METHODS—Corneal haze in rabbits was produced with −9.00 diopters (D) PRK. Fibrosis in cultured human and rabbit corneal fibroblasts was activated with TGFβ1. Vorinostat (25 μm) was topically applied once for 5 minutes on rabbit cornea immediately after PRK for in vivo studies. Vorinostat (0 to 25 μm) was given to human/rabbit corneal fibroblasts for 5 minutes or 48 hours for in vitro studies. Slit-lamp microscopy, TUNEL assay, and trypan blue were used to determined vorinostat toxicity, whereas real-time polymerase chain reaction, immunocytochemistry, and immunoblotting were used to measure its efficacy. RESULTS—Single 5-minute vorinostat (25 μm) topical application on the cornea following PRK significantly reduced corneal haze (Pin vivoscreened 4 weeks after PRK. Vorinostat reduced TGFβ1-induced fibrosis in human and rabbit corneas in vitro in a dose-dependent manner without altering cellular viability, phenotype, or proliferation. CONCLUSIONS—Vorinostat is non-cytotoxic and safe for the eye and has potential to prevent laser-induced corneal haze in patients undergoing PRK for high myopia

    Hemostatic efficacy of an advanced bipolar sealer in open gynecologic, thoracic, and colectomy procedures: A prospective cohort study

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    Background An advanced bipolar (ABP) tissue sealer designed for division of major vessels in open procedures was evaluated in a prospective post-market study. The objective was to provide clinical data for assessment of vessel transection, hemostatic performance and ease of use of the ABP device during open colectomy, gynecologic, and thoracic operations. Materials and methods The ABP test device was used in colectomy (n = 36), gynecologic (n = 44), and thoracic (n = 21) procedure groups. Vessels transected with the ABP device were graded intraoperatively on a hemostasis scale of 1–4, defined as follows: Grade1, no bleeding; Grade 2, minor bleeding with no intervention; Grade 3, minor bleeding requiring touchup with the test device or monopolar cautery; and Grade 4, significant bleeding requiring intervention with any additional hemostatic product. The primary performance measure was the percentage of vessels that achieved hemostasis grades ≤3. The primary safety endpoint was the summarization of all ABP device-related adverse events (AEs). Results For all three procedure groups together, 302 (96.2%) of 314 total vessel transections were scored as hemostasis grades ≤ 3, including 270 (86.0%) that were rated Grade 1. Twelve transections (3.8%) were Grade 4, which included 9 vessels transected in the gynecologic group and 3 in the thoracic group. Three subjects experienced a total of 4 device-related AEs, consisting of hematoma, hypotension, procedural pain, and superficial thermal burn. All 4 device-related AEs were mild in severity. Conclusion The advanced bipolar device exhibited effective hemostasis, an acceptable safety profile, and ease of use during colectomy, thoracic, and gynecologic procedures
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