124 research outputs found

    Conceptual design study of a six-man solid electrolyte system for oxygen reclamation

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    A six-man solid electrolyte oxygen regeneration system (SEORS) that will produce 12.5 lbs/day of oxygen has been designed. The SEORS will simultaneously electrolyze both carbon dioxide and water vapor and be suitable for coupling with a carbon dioxide concentration system of either molecular sieve, solid amine or hydrogen depolarized electrochemical type. The total system will occupy approximately 19 cu ft (34.5 in. x .26 in. x 36 in. high) and will weigh approximately 500 pounds. It is estimated that the total electrical power required will be 1783 watts. The system consists of three major components; electrolyzer, hydrogen diffuser, and carbon deposition reactor. There are 108 electrolysis stacks of 12 cells each in the electrolyzer. Only 2/3 of the 108 stacks will be operated at a time; the remainder will be held in reserve. The design calls for 96 palladium membranes for hydrogen removal to give 60 percent redundancy. Four carbon deposition reactors are employed. The iron catalyst tube in each reactor weighs 7.1 lb and 100 percent redundancy is allowed

    Pb(II) Induces Scramblase Activation and Ceramide-Domain Generation in Red Blood Cells

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    The mechanisms of Pb(II) toxicity have been studied in human red blood cells using confocal microscopy, immunolabeling, fluorescence-activated cell sorting and atomic force microscopy. The process follows a sequence of events, starting with calcium entry, followed by potassium release, morphological change, generation of ceramide, lipid flip-flop and finally cell lysis. Clotrimazole blocks potassium channels and the whole process is inhibited. Immunolabeling reveals the generation of ceramide-enriched domains linked to a cell morphological change, while the use of a neutral sphingomyelinase inhibitor greatly delays the process after the morphological change, and lipid flip-flop is significantly reduced. These facts point to three major checkpoints in the process: first the upstream exchange of calcium and potassium, then ceramide domain formation, and finally the downstream scramblase activation necessary for cell lysis. In addition, partial non-cytotoxic cholesterol depletion of red blood cells accelerates the process as the morphological change occurs faster. Cholesterol could have a role in modulating the properties of the ceramide-enriched domains. This work is relevant in the context of cell death, heavy metal toxicity and sphingolipid signaling.AGA was a predoctoral student supported by the Basque Government and later by the University of the Basque Country (UPV/EHU). This work was also supported in part by grants from the Spanish Government (FEDER/MINECO BFU 2015-66306-P to F.M.G. and A.A.) and the Basque Government (IT849-13 to F.M.G. and IT838-13 to A.A.), and by the Swiss National Science Foundation

    From Gardner fibroma diagnosis to constitutional APC mutation detection: a one-way street.

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    We report a young child without a family history of FAP, who promptly underwent APC testing after the histological confirmation of a paraspinal GAF that was not isolated. Our case report reinforces the suggestion advanced by previous authors for an APC analysis in all patients with GAF

    Approach to the treatment of primary anterior shoulder dislocation: A review.

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    Glenohumeral joint dislocation is common among younger, active patients. Anterior dislocation is the most common direction of instability following a traumatic event. Due to a high rate of recurrence following primary traumatic anterior shoulder dislocation, an evidence-based approach is necessary to determine the best treatment regime for a patient presenting with this problem. A history, physical examination, and radiographic imaging can help guide treatment recommendations by determining the extent of soft tissue damage following dislocation. Controversies in the treatment of the first-time dislocator include the length and position of immobilization following dislocation, and the role of initial surgical stabilization. This article outlines the treatment options for the first-time glenohumeral dislocator, with an emphasis on the available evidence in the literature. Where applicable, the criteria known as the Strength of Recommendation Taxonomy were used to summarize the strength of evidence available for recommendations

    Large-scale metal MEMS mirror arrays with integrated electronics

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    Design, microfabrication, and integration of a micromachined spatial light modulator (μSLM) device are described. A large array of electrostatically actuated, piston-motion MEMS mirror segments make up the optical surface of the μSLM. Each mirror segment is capable of altering the phase of reflected light by up to one wavelength for infrared illumination (λ = 1.5 μm), with 4-bit resolution. The device is directly integrated with complementary metal-oxide semiconductor (CMOS) electronics, for control of spatial optical wavefront. Integration with electronics is achieved through direct fabrication of MEMS actuators and mirror structures on planarized foundry-type CMOS electronics. Technical approaches to two significant challenges associated with manufacturing the μSLM are discussed: integration of the MEMS array with the electronic driver array and production of optical-quality mirror elements using a metal-polymer surface micromachining process

    Comparing the Efficacy of True-Volume Analysis Using Magnetic Resonance Imaging With Computerized Tomography and Conventional Methods of Evaluation in Cystic Osteochondral Lesions of the Talus: A Pilot Study.

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    UNLABELLED: METHODS: With IRB approval, an institutional radiology database was queried for patients with cystic OLT that had undergone and failed microfracture and had compatible CT and MR scans between 2011 and 2016. Five lesions, previously analyzed and described in the literature using CT true-volume, were selected. 10 orthopedic surgeons independently estimated the volume of these 5 OLT via standard MRI. Next, 3D reconstructions were created and morphometric true-volume (MTV) analysis measurements of each OLT were generated. The percent change in volumes from CT and MR was compared based upon MTVs determined from 3D reconstructive analysis. RESULTS: The volume calculated using conventional methods in CT and MR scans grossly overestimated the size by of the OLT by 285-864% and 56-374% respectively when compared to 3D true-volume analysis of those CT and MR scans. CONCLUSIONS: This study demonstrates that true-volume is more accurate for calculating lesion size than conventional methods. Additionally, when comparing MRI and CT, thin slice CT true-volume is superior to MRI true-volume. True-volume calculation improves accuracy with CT and MRI and should be recommended for use in revision OLT cases
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