1,263 research outputs found

    A KINEMATIC COMPARISON OF RUNNING ON TREADMILL AND OVERGROUND SURFACES

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    Treadmills are often used for research in sport running shoes and physical training. The purpose of this study was to compare the kinematics in treadmill and overground running, and to investigate if the shoe testing on treadmill can reflect the performance of the running shoes on overground surfaces. Thirteen male subjects were recruited to run on treadmill, tartan, grass and concrete surfaces. Effective vertical stiffness, temporal and kinematic parameters were measured. The results showed that the running patterns within overground surfaces were not significantly different, while the significant differences were found between treadmill and overground running

    A KINETIC COMPARISON OF RUNNING ON TREADMILL AND OVERGROUND SURFACES: AN ANALYSIS OF PLANTAR PRESSURE

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    The purpose of this study was to compare the plantar pressure in treadmill and overground running. It aimed to investigate whether treadmill is a suitable surface to carry out running shoe cushioning test. Fourteen male volunteers were recruited to run on four different running conditions i.e. treadmill, tartan, grass, and concrete with controlled running speed. A mobile plantar pressure measuring system was employed and peak pressure was measured. The results showed that the plantar pressure of treadmill running was different to that of overground running in total foot, medial midfoot, lateral midfoot and lesser toes

    ELECTROMYOGRAPHIC ANALYSIS ON LOWER EXTREMITY MUSCLES DURING OVERGROUND AND TREADMILL RUNNING

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    The goal of this study was to compare treadmill running with overground running, so as to investigate if the shoe testing and training on treadmill can reflect the overground performance. Thirteen Chinese male subjects were instructed to run on the four conditions (1.Treadmill, 2.Tartan, 3.Grass, 4.Concrete). Comparisons between running conditions were made for muscle activity. The electromyography (EMG) signals from rectus femoris, tibialis anterior, biceps fermoris and medial gastrocnemius in one stride were evaluated. Results of the root mean square of EMG signal in rectus femoris, biceps femoris and gastrocnemius were found to be significantly different between overground and treadmill running during stance phase and the time point of toe off

    Oral health and later coronary heart disease: Cohort study of one million people

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    AIMS: Systematic reviews report an association between poorer oral health and an increased risk of coronary heart disease. This contentious relationship may not be causal but existing studies have been insufficiently well powered comprehensively to examine the role of confounding, particularly by cigarette smoking. Accordingly, we sought to examine the role of smoking in generating the relationship between oral health and coronary heart disease in life-long non-smokers. METHODS AND RESULTS: In the Korean Cancer Prevention Study, 975,685 individuals (349,579 women) aged 30–95 years had an oral examination when tooth loss, a widely used indicator of oral health, was ascertained. Linkage to national mortality and hospital registers over 21 years of follow-up gave rise to 64,784 coronary heart disease events (19,502 in women). In the whole cohort, after statistical adjustment for age, there was a moderate, positive association between tooth loss and coronary heart disease in both men (hazard ratio for seven or more missing teeth vs. none; 95% confidence interval 1.08; 1.02, 1.14; Ptrend across tooth loss groups <0.0001) and women (1.09; 1.01, 1.18; Ptrend 0.0016). Restricting analyses to a subgroup of 464,145 never smokers (25,765 coronary heart disease events), however, resulted in an elimination of this association in men (1.01; 0.85, 1.19); Ptrend 0.7506) but not women (1.08; 0.99, 1.18; Ptrend 0.0086). CONCLUSION: In men in the present study, the relationship between poor oral health and coronary heart disease risk appeared to be explained by confounding by cigarette smoking so raising questions about a causal link

    Scaling and trends of hourly precipitation extremes in two different climate zones – Hong Kong and the Netherlands

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    Hourly precipitation extremes in very long time series from the Hong Kong Observatory and the Netherlands are investigated. Using the 2 m dew point temperature from 4 h before the rainfall event as a measure of near surface absolute humidity, hourly precipitation extremes closely follow a 14% per degree dependency – a scaling twice as large as following from the Clausius-Clapeyron relation. However, for dew point temperatures above 23 °C no significant dependency on humidity was found. Strikingly, in spite of the large difference in climate, results are almost identical in Hong Kong and the Netherlands for the dew point temperature range where both observational sets have sufficient data. Trends in hourly precipitation extremes show substantial increases over the last century for both De Bilt (the Netherlands) and Hong Kong. For De Bilt, not only the long term trend, but also variations in hourly precipitation extremes on an inter-decadal timescale of 30 yr and longer, can be linked very well to the above scaling; there is a very close resemblance between variations in dew point temperature and precipitation intensity with an inferred dependency of hourly precipitation extremes of 10 to 14% per degree. For Hong Kong there is no connection between variations in humidity and those in precipitation intensity in the wet season, May to September. This is consistent with the found zero-dependency of precipitation intensity on humidity for dew points above 23 °C. Yet, outside the wet season humidity changes do appear to explain the positive trend in hourly precipitation extremes, again following a dependency close to twice the Clausius-Clapeyron relation

    Sex hormones and apoptosis and immunoglobulin production in systemic lupus erythematosus

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    BACKGROUND: SLE is an autoimmune disease that affects predominantly female of reproductive age. Previous studies have suggested an immunomodulatory role of sex hormones in the pathogenesis of SLE. Objectives: To examine the effects of various sex hormones on apoptosis and immunoglobulin production by peripheral blood mononuclear cells (PBMCs) in SLE patients …published_or_final_versio

    Rapid detection of high-emitting vehicles by on-road remote sensing technology improves urban air quality.

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    Vehicle emissions are the most important source of air pollution in the urban environment worldwide, and their detection and control are critical for protecting public health. Here, we report the use of on-road remote sensing (RS) technology for fast, accurate, and cost-effective identification of high-emitting vehicles as an enforcement program for improving urban air quality. Using large emission datasets from chassis dynamometer testing, RS, and air quality monitoring, we found that significant percentages of in-use petrol and LPG vehicles failed the emission standards, particularly the high-mileage fleets. The RS enforcement program greatly cleaned these fleets, in terms of high-emitter percentages, fleet average emissions, roadside and ambient pollutant concentrations, and emission inventory. The challenges of the current enforcement program are conservative setting of cut points, single-lane measurement sites, and lack of application experience in diesel vehicles. Developing more accurate and vertical RS systems will improve and extend their applications

    Viral genetic determinants of h5n1 influenza viruses that contribute to cytokine dysregulation

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    Human disease caused by highly pathogenic avian influenza (H5N1) is associated with fulminant viral pneumonia and mortality rates in excess of 60%. Cytokine dysregulation is thought to contribute to its pathogenesis. In comparison with human seasonal influenza (H1N1) viruses, clade 1, 2.1, and 2.2 H5N1 viruses induced higher levels of tumor necrosis factor-α in primary human macrophages. To understand viral genetic determinants responsible for this hyperinduction of cytokines, we constructed recombinant viruses containing different combinations of genes from high-cytokine (A/Vietnam/1203/04) and low-cytokine (A/WSN/33) phenotype HlNl viruses and tested their cytokine-inducing phenotype in human macrophages. Our results suggest that the H5N1 polymerase gene segments, and to a lesser extent the NS gene segment, contribute to cytokine hyperinduction in human macrophages and that a putative H5 pandemic virus that may arise through genetic reassortment between H5N1 and one of the current seasonal influenza viruses may have a markedly altered cytokine phenotype. © 2009 by the Infectious Diseases Society of America. All rights reserved.published_or_final_versio

    The PB2 mutation with lysine at 627 enhances the pathogenicity of avian influenza (H7N9) virus which belongs to a non-zoonotic lineage

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    A novel avian-origin influenza A (H7N9) virus emerged in China in 2013 and has caused zoonotic disease in over 1123 persons with an overall mortality around 30%. Amino acid changes at the residues 591, 627 and 701 of polymerase basic protein 2 (PB2) have been found frequently in the human H7N9 isolates but not in viruses isolated from avian species. We have recently identified a cluster of H7N9 viruses in ducks which circulated in China prior to the first recognition of zoonotic disease in 2013. These duck viruses have genetic background distinct from the zoonotic H7N9 lineage. We found that the introduction of PB2 mutation with K at 627 but not K at 591 or N at 701 to the duck H7N9 virus led to increased pathogenicity in mice. We also found that the induction of pro-inflammatory cytokines including TNF-α, IP-10, MCP-1 and MIP-1α were associated with increased severity of infection. We conclude that introduction of the mammalian adaptation mutations into the PB2 gene of duck H7N9 viruses, which are genetically unrelated to the zoonotic H7N9 lineage, can also enhance pathogenicity in mice.published_or_final_versio

    Impact of potential engine malfunctions on fuel consumption and gaseous emissions of a Euro VI diesel truck

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    © 2019 Elsevier Ltd Although new vehicles are designed to comply with specific emission regulations, their in-service performance would not necessarily achieve them due to wear-and-tear and improper maintenance, as well as tampering or failure of engine control and exhaust after-treatment systems. In addition, there is a lack of knowledge on how significantly these potential malfunctions affect vehicle performance. This study was therefore conducted to simulate the effect of various engine malfunctions on the fuel consumption and gaseous emissions of a 16-tonne Euro VI diesel truck using transient chassis dynamometer testing. The simulated malfunctions included those that would commonly occur in the intake, fuel injection, exhaust after-treatment and other systems. The results showed that all malfunctions increased fuel consumption except for the malfunction of EGR fully closed which reduced fuel consumption by 31%. The biggest increases in fuel consumption were caused by malfunctions in the intake system (16%–43%), followed by the exhaust after-treatment (6%–30%), fuel injection (4%–24%) and other systems (6%–11%). Regarding pollutant emissions, the effect of engine malfunctions on HC and CO emissions was insignificant, which remained unchanged or even reduced for most cases. An exception was EGR fully open which increased HC and CO emissions by 343% and 1124%, respectively. Contrary to HC and CO emissions, NO emissions were significantly increased by malfunctions. The largest increases in NO emissions were caused by malfunctions in the after-treatment system, ranging from 38% (SCR) to 1606% (DPF pressure sensor). Malfunctions in the fuel injection system (24%–1259%) and intercooler (438%–604%) could also increase NO emissions markedly. This study demonstrated clearly the importance of having properly functioning engine control and exhaust after-treatment systems to achieve the required performance of fuel consumption and pollutant emissions
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