21,811 research outputs found

    Use of optimization to predict the effect of selected parameters on commuter aircraft performance

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    The relationships between field length and cruise speed and aircraft direct operating cost were determined. A gradient optimizing computer program was developed to minimize direct operating cost (DOC) as a function of airplane geometry. In this way, the best airplane operating under one set of constraints can be compared with the best operating under another. A constant 30-passenger fuselage and rubberized engines based on the General Electric CT-7 were used as a baseline. All aircraft had to have a 600 nautical mile maximum range and were designed to FAR part 25 structural integrity and climb gradient regulations. Direct operating cost was minimized for a typical design mission of 150 nautical miles. For purposes of C sub L sub max calculation, all aircraft had double-slotted flaps but with no Fowler action

    Use of optimization to predict the effect of selected parameters on commuter aircraft performance

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    An optimizing computer program determined the turboprop aircraft with lowest direct operating cost for various sets of cruise speed and field length constraints. External variables included wing area, wing aspect ratio and engine sea level static horsepower; tail sizes, climb speed and cruise altitude were varied within the function evaluation program. Direct operating cost was minimized for a 150 n.mi typical mission. Generally, DOC increased with increasing speed and decreasing field length but not by a large amount. Ride roughness, however, increased considerably as speed became higher and field length became shorter

    Drink wise, age well; reducing alcohol related harm among people over 50: a study protocol

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    Background: Evidence suggests that the use of alcohol among older adults (defined as those aged 50+) has increased in recent years, with people aged 55-64 now more likely to exceed the recommended weekly guidelines than any other age group. Methods/ design: This is a quasi-experimental study with a before-after design. A postal questionnaire will be sent to 76,000 people aged 50 and over registered with a general practice in five different 'demonstration' (intervention) and control areas in the UK. Multiple interventions will then be delivered in demonstration areas across the UK. At the end of the programme, a postal questionnaire will be sent to the same individuals who completed it pre-programme to establish if there has been a reduction in alcohol use, at-risk drinking and alcohol related problems. Qualitative interviews with clients and staff will explore how the interventions were experienced; how they may work to bring about change and to identify areas for practice improvements. Discussion: This study protocol describes a multi-level, multi-intervention prevention-to-treatment programme which aims to reduce alcohol-related harm in people aged 50 and over

    A Cholecystokinin B Receptor-Specific Aptamer Does Not Activate Receptor Signaling

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    Targeted nanoparticles which deliver effective doses of chemotherapeutic drugs directly to pancreatic tumors could improve treatment efficacy without the toxicities associated with systemic drug administration. One protein on tumor cells that can be targeted by nanoparticles is a G-protein coupled cell surface receptor, the cholecystokinin B receptor (CCKBR). Previously, we had shown that attaching the CCKBR ligand gastrin to the surface of nanoparticles can enhance their up-take by tumors. The drawback of using gastrin is that it can also activate the receptor, causing tumor cell growth. This study shows that a DNA aptamer that binds to the CCKBR and enhances nanoparticle up-take by tumors does not activate this receptor. PANC-1 cells, a cultured human pancreatic cancer cell line, were treated for 24 h with CCKBR aptamer 1153. Cell lysates were run on Bis-Tris gels, transferred to membranes, blocked in 5% BSA and incubated overnight with primary antibodies, including antibodies directly against phosphorylated-Akt (Ser473), total Akt, and beta-actin, a protein loading control. Although the CCKBR aptamer 1153 is internalized by pancreatic cancer cells in a receptor-mediated fashion, it does not stimulate cell proliferation. Because of this, we anticipate that it will not activate CCKBR signaling. If aptamer 1153 does not activate downstream receptor signaling, our future work will test whether the aptamer could be used to specifically direct drug-containing nanoparticles to tumors, making chemotherapy treatments for pancreatic cancer patients more effective with fewer off-target effects and toxicity

    How much dystrophin is enough: the physiological consequences of different levels of dystrophin in the mdx mouse

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    Splice modulation therapy has shown great clinical promise in Duchenne muscular dystrophy, resulting in the production of dystrophin protein. Despite this, the relationship between restoring dystrophin to established dystrophic muscle and its ability to induce clinically relevant changes in muscle function is poorly understood. In order to robustly evaluate functional improvement, we used in situ protocols in the mdx mouse to measure muscle strength and resistance to eccentric contraction-induced damage. Here, we modelled the treatment of muscle with pre-existing dystrophic pathology using antisense oligonucleotides conjugated to a cell-penetrating peptide. We reveal that 15% homogeneous dystrophin expression is sufficient to protect against eccentric contraction-induced injury. In addition, we demonstrate a >40% increase in specific isometric force following repeated administrations. Strikingly, we show that changes in muscle strength are proportional to dystrophin expression levels. These data define the dystrophin restoration levels required to slow down or prevent disease progression and improve overall muscle function once a dystrophic environment has been established in the mdx mouse model

    Information requirements for supersonic transport operation Final report

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    Effects of meteorological parameters and instrument errors on vertical flight performance of supersonic transport

    Positronium oscillations to Mirror World revisited

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    We present a calculation of the branching ratio of orthopositronium decay into an invisible mode, which is done in the context of Mirror World models, where ordinary positronium can disappear from our world due to oscillation into its mirror twin. In this revision we clarify some formulas and approximations used previously, correct them at some places, add new effects relevant for a feasible experiment and finally perform a combined analysis. We include into consideration various effects due to external magnetic and electric fields, collisions with cavity walls and scattering off gas atoms in the cavity. Oscillations of the Rydberg positroniums are also considered. To perform a numerical estimates in a realistic case we wrote computer code, which can be adopted in any experimental setup. Its work is illustrated with an example of a planned positronium experiment within the AEgIS project.Comment: 23 pages, 4 figures, typos corrected, references added, published versio

    Integration Of An Extended Octagonal Ring Transducer And Soil Coulterometer For Identifying Soil Compaction

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    The soil coulterometer is an “on‐the‐go” electro‐mechanical system which collects impedance force data at multiple depths using an oscillating coulter. During the initial testing (summer 2006), only vertical soil impedance force data was collected using a pressure sensor. To improve the performance of the coulterometer, an extended octagonal ring transducer was integrated into the system to collect both the horizontal and vertical impedance forces given by the soil. In the summer of 2007, data was collected using the revised sensor from a typical central Kentucky field setting in a 0.8‐ha (2‐acre) plot. Four passes were made with the coulterometer. Seventy five coulter oscillations between depths of 100 mm (4 in.) and 305 mm (12 in.) were obtained for each pass. Ten standard cone penetrometer measurements were taken for each pass between depths of 100 mm (4 in.) and 305 mm (12 in.) using a multi‐probe soil cone penetrometer. Three soil bulk density and water content measurements between depths of 100 mm (4 in.) and 305 mm (12 in.) in steps of 50 mm (2 in.) were taken for each pass using a nuclear soil moisture/density gauge. Simple linear regression analysis was used to find the relationship between coulter indices (kN/m), cone index (MPa), dry soil bulk density (Mg/m3) and water content (%).Coefficients of determination (R2) as high as 0.996 were obtained between coulter indices and dry soil bulk density measurements and 0.998 for coulter indices and water content measurements
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