99 research outputs found

    Lipoprotein lipase activity is decreased in a large cohort of patients with coronary artery disease and is associated with changes in lipids and lipoproteins

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    Lipoprotein lipase (LPL) is crucial in the hydrolysis of triglycerides (TG) in TG-rich lipoproteins in the formation of HDL particles. As both these lipoproteins play an important role in the pathogenesis of atherosclerotic vascular disease, we sought to assess the relationship between post-heparin LPL (PH-LPL) activity and lipids and lipoproteins in a large, well-defined cohort of Dutch males with coronary artery disease (CAD). These subjects were drawn from the REGRESS study, totaled 730 in number and were evaluated against 75 healthy, normolipidemic male controls. Fasting mean PH-LPL activity in the CAD subjects was 108 46 mU/ml, compared to 138 44 mU/ml in controls (P < 0.0001). When these patients were divided into activity quartiles, those in the lowest versus the highest quartile had higher levels of TG (P < 0.001), VLDLc and VLDL-TG (P = 0.001). Conversely, levels of TC, LDL, and HDLc were lower in these patients (P = 0.001, P = 0.02, and P = 0.001, respectively). Also, in this cohort PH-LPL relationships with lipids and lipoproteins were not altered by apoE genotypes. The frequency of common mutations in the LPL gene associated with partial LPL deficiency (N291S and D9N carriers) in the lowest quartile for LPL activity was more than double the frequency in the highest quartile (12.0% vs. 5.0%; P = 0.006). By contrast, the frequency of the S447X LPL variant rose from 11.5% in the lowest to 18.3% (P = 0.006) in the highest quartile. This study, in a large cohort of CAD patients, has shown that PH-LPL activity is decreased (22%; P = 0.001) when compared to controls; that the D9N and N291S, and S447X LPL variants are genetic determinants, respectively, in CAD patients of low and high LPL PH-LPL activities; and that PH-LPL activity is strongly associated with changes in lipids and lipoproteins

    Fore-arc deformation and underplating at the northern Hikurangi margin, New Zealand

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    Geophysical investigations of the northern Hikurangi subduction zone northeast of New Zealand, image fore‐arc and surrounding upper lithospheric structures. A seismic velocity (Vp) field is determined from seismic wide‐angle data, and our structural interpretation is supported by multichannel seismic reflection stratigraphy and gravity and magnetic modeling. We found that the subducting Hikurangi Plateau carries about 2 km of sediments above a 2 km mixed layer of volcaniclastics, limestone, and chert. The upper plateau crust is characterized by Vp = 4.9–6.7 km/s overlying the lower crust with Vp > 7.1 km/s. Gravity modeling yields a plateau thickness around 10 km. The reactivated Raukumara fore‐arc basin is >10 km deep, deposited on 5–10 km thick Australian crust. The fore‐arc mantle of Vp > 8 km/s appears unaffected by subduction hydration processes. The East Cape Ridge fore‐arc high is underlain by a 3.5 km deep strongly magnetic (3.3 A/m) high‐velocity zone, interpreted as part of the onshore Matakaoa volcanic allochthon and/or uplifted Raukumara Basin basement of probable oceanic crustal origin. Beneath the trench slope, we interpret low‐seismic‐velocity, high‐attenuation, low‐density fore‐arc material as accreted and recycled, suggesting that underplating and uplift destabilizes East Cape Ridge, triggering two‐sided mass wasting. Mass balance calculations indicate that the proposed accreted and recycled material represents 25–100% of all incoming sediment, and any remainder could be accounted for through erosion of older accreted material into surrounding basins. We suggest that continental mass flux into the mantle at subduction zones may be significantly overestimated because crustal underplating beneath fore‐arc highs have not properly been accounted for

    Continent elevation, mountains, and erosion : freeboard implications

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    Author Posting. © American Geophysical Union, 2009. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 114 (2009): B05410, doi:10.1029/2008JB006176.To the simplest approximation, Earth's continental crust is a floating aggregate on the planet's surface that is first attracted to subduction zones and, upon arrival, thickened by mountain building (then producing some extension). Thickened regions are thinned again by erosion. A comparison between 65 Ma and the present shows that the modern state is significantly more mountainous. An estimated average continental elevation increase relative to average ocean floor depth of about 54 m and sea level decrease relative to the ocean floor of about 102 m add up to a 156-m increase of continent elevation over sea level since 65 Ma. Both are affected most strongly by the roughly 1.7% continent surface area decrease caused by Cenozoic mountain building. This includes contributions from erosion. Volumes of sediments in deltas and submarine fans indicate an average thickness of 371 m deposited globally in the ocean basins since 65 Ma. This relatively large change of continent area over a short span of Earth history has significant consequences. Extrapolating, if continent area change exceeded 5% in the past, either severe erosion or flooded continents occurred. If continent elevation (freeboard) remains at the present value of a few hundred meters, the past continent-ocean area ratio might have been quite different, depending on earlier volumes of continental crust and water. We conclude that, along with the ages of ocean basins, continental crustal thickening exerts a first-order control on the global sea level over hundreds of million years

    ЭФФЕКТИВНОСТЬ ИСПОЛЬЗОВАНИЯ МОЛОЧНО-КИСЛОЙ ДОБАВКИ В КОРМЛЕНИИ ЦЫПЛЯТ-БРОЙЛЕРОВ

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    The article reveals aspects of developing animal indexes and productivity of broilers when applying lacto-acid additive. The paper applies experimental data and shows efficiency of lacto-acid additive applying in ratios of broilers. The research is aimed at estimation of lacto-acid efficiency when applying it in feed ratios together with activated feeds. The research focuses on estimating different ways of lacto-acid additive applying and its influence on broilers productivity; defining the appropriate rate of additive in poultry feeding; revealing economic efficiency of lacto-acid additive applying in feeding young birds. The authors declare efficient amount of lacto-acid additive is 0.2 % of ratio mass. They note average daily liveweight gain increases on 2.5 % and overall liveweight gain on 3 %; feed consumption pro 1 kg of body weight is reduced. The article proves applying of 0.2 % lacto-acid additive together with activated feeds reduces feed consumption pro 1 kg of body weight gain; when specialists apply 0.3 % of lacto-acid additive this leads to increasing of feed consumption on 10 %. When birds receive granular lacto-acid additive, this increases average daily liveweight gain on 2.5 % and overall liveweight gain on 6.1 % and reduces feed consumption on 06.6 % and 6.6 % correspondently. The authors conclude feeding broilers with granular lacto-acid additive allows increasing production profitability.Рассматриваются вопросы улучшения зоотехнических показателей и продуктивности цыплят-бройлеров при введении молочно-кислой добавки. На основе экспериментальных данных установлена эффективность введения молочно-кислой добавки (МКД) в рационы цыплят-бройлеров с активированным кормом (АВК). Оптимальное количество МКД составляет 0,2% от массы рациона. При этом увеличивается среднесуточный и абсолютный прирост на 2,5 и 3% соответственно, снижаются затраты корма на 1 кг прироста живой массы. Применение МКД совместно с АВК в количестве 0,2% снижает затраты корма на 1 кг прироста, а увеличение ее доли до 0,3% приводит к увеличению затрат корма на 10%. Потребление птицей МКД в гранулированном виде способствовало увеличению среднесуточного и абсолютного прироста живой массы на 2,5–6,1% и снижению затрат кормов на 0,6–6,6% соответственно. Скармливание МКД в гранулированном виде позволяет повысить рентабельность производства

    Analysis of residual strength of a helicopter tail boom

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    The aim of this work is to determine the residual strength of a Mi-24 helicopter's tail boom with a structural damage. The idea of this work has come from the fact that these helicopters are operated on a battlefleld and often suffer such damages. It may be crucial to make a quick estimation whether any particular damage can cause a critical failure to the whole structure. The scope of this work covers static loading of the structure during landing. The analysis has been based on a numerical model that makes use of the Finite Element Method. The model has been developed using reverse engineering techniques. Structural discontinuities have been modelled in characteristic sections where stress concentrations occur. Boundary conditions and loads applied have been chosen to simulate normal and hard landings. Two failure criteria have been chosen: one based on the Crack Tip Opening Angle (CTOA) method that enables very efficient verification, and the second concerning the tail boom tip dislocation, taken from the helicopter,s alignment manual. The specific load history has been designed to enable detection of tail boom tip dislocation due to plastic strain in the vicinity of damage tips after the hard landing

    Preliminary Verification of Selected Solutions for Crack Detection

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    Throughout its service life an aircraft is subjected to varying loads. Because of those periodically appearing stresses, undesirable and irreversible changes in structure may occur. As a consequence, cracks are formed, which reduce aircraft structural strength, significantly affecting structural integrity. For that reason, intensive research works are carried out around the world to develop innovative and reliable methods for detection of cracks initiation and propagation. This paper presents two methods of crack detection. One of them uses wireless polymer gages for determining deformation in a test region. The other one uses electrical, resistive ladder sensors for detection of cracks and their length determination

    Fatigue Life Estimation of the Tail Boom and Vertical Stabilizer of MI-24 Helicopter

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    The aim of this work was to estimate fatigue life of the Mi-24 helicopter tail boom and vertical stabilizer sheathing. The analysis was based on a numerical model of the helicopter airframe crucial to obtain stress fields under defined loads and to estimate fatigue life. In order to do so, the load spectrum, specific for Polish army helicopters, was obtained by means of strain gauge measurements during a series of experimental flights. Data collected during flights was post-processed to create a characteristic ten hour spectrum that would statistically represent the flight profile for Polish Army Mi-24 helicopters. The third crucial element of the analysis was the safe S-N curve that was created on the basis of 2024-T3 aluminum S-N curve. Two factors were introduced in order to change the curve in a way that would guarantee a higher level of certainty that the outcome is not overrated. As a result of this analysis the total fatigue life was estimated including the list of critical locations in which fatigue damage is prone to occur. These regions are going to be carefully examined during scheduled inspections
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