710 research outputs found
Differences in muscle pain and plasma creatine kinase activity after \'up\' and \'down\' Comrades marathons
Objective. The aim of this study was to compare the acute changes in muscle pain and plasma creatine kinase (CK) activity following the ‘up' and ‘down' Comrades marathon.
Design. This was a quasi-experimental design. Eleven male runners (39.7±9.3 years) completed the ‘up' Comrades marathon, and 11 male runners (41.0±8.4 years) completed the ‘down' Comrades marathon the following year. Maximum oxygen consumption
and peak treadmill running speed were measured 2 weeks before the race. Daily measurements of muscle pain and plasma creatine kinase (CK) activity were recorded 1 day before, and for 7 days after the race.
Results. Muscle pain remained significantly elevated for up to 7 days after the Comrades marathon, compared with pre-race values (
Metabolically healthy and unhealthy obesity: differential effects on myocardial function according to metabolic syndrome, rather than obesity.
BACKGROUND: The term 'metabolically healthy obese (MHO)' is distinguished using body mass index (BMI), yet BMI is a poor index of adiposity. Some epidemiological data suggest that MHO carries a lower risk of cardiovascular disease (CVD) or mortality than being normal weight yet metabolically unhealthy. OBJECTIVES: We aimed to undertake a detailed phenotyping of individuals with MHO by using imaging techniques to examine ectopic fat (visceral and liver fat deposition) and myocardial function. We hypothesised that metabolically unhealthy individuals (irrespective of BMI) would have adverse levels of ectopic fat and myocardial dysfunction compared with MHO individuals. SUBJECTS: Individuals were categorised as non-obese or obese (BMI ⩾30 kg m(-2)) and as metabolically healthy or unhealthy according to the presence or absence of metabolic syndrome. METHODS: Sixty-seven individuals (mean±s.d.: age 49±11 years) underwent measurement of (i) visceral, subcutaneous and liver fat using magnetic resonance imaging and proton magnetic resonance spectroscopy, (ii) components of metabolic syndrome, (iii) cardiorespiratory fitness and (iv) indices of systolic and diastolic function using tissue Doppler echocardiography. RESULTS: Cardiorespiratory fitness was similar between all groups; abdominal and visceral fat was highest in the obese groups. Compared with age- and BMI-matched metabolically healthy counterparts, the unhealthy (lean or obese) individuals had higher liver fat and decreased early diastolic strain rate, early diastolic tissue velocity and systolic strain indicative of subclinical systolic and diastolic dysfunction. The magnitude of dysfunction correlated with the number of components of metabolic syndrome but not with BMI or with the degree of ectopic (visceral or liver) fat deposition. CONCLUSIONS: Myocardial dysfunction appears to be related to poor metabolic health rather than simply BMI or fat mass. These data may partly explain the epidemiological evidence on CVD risk relating to the different obesity phenotypes
Assessing the impact of the 2011 EU Transport White Paper - a rail freight demand forecast up to 2050 for the EU27
Purpose
This paper presents a rail freight forecast for the EU27 for the period up to 2050.
Background
Rail freight’s market share of the transport sector in Europe has been falling or remained stagnant since 1970. In contrast, the share of road freight has been increasing. As rail freight transport is generally considered an environmentally friendly option, various measures have been implemented for more than two decades, at national and European level, to encourage a modal shift from road to rail. In the latest EU Transport White paper policy paper of 2011, an optimistic target is set for greater use of rail freight transport, in both the near and the longer term future. Specifically: a modal shift, from road to rail, and waterway transport, of 30 % by 2030 and 50 % by 2050 - for distances greater than 300 km.
Methodology
With the aforesaid policy objectives, the current research examines the possible effects of these aims in terms of future levels of rail freight demand. This research relies heavily upon the EU TRANS-TOOLS modelling tool and explores three scenarios. A Reference scenario - with no significant change to current rail freight policy, infrastructure and existing trends is considered alongside two White Paper scenarios (High and Low) which take more optimistic views of the white paper policy objectives.
Results
The study finds that the Reference and White Paper Low scenarios demonstrate similar results in terms of growth and modal split. In stark contrast, the White paper High scenario results show that demand for rail freight services almost doubles compared to the Reference values.
Conclusions
The rail sector is expected to attract new commodities from road transport such as foodstuffs and building and transport materials. To meet this demand, the rail industry - including operators, infrastructure managers and governments - will have to invest in technologies, infrastructure and terminals with a view to significantly increasing productivity against current levels
Color & Weak triplet scalars, the dimuon asymmetry in decay, the top forward-backward asymmetry, and the CDF dijet excess
The new physics required to explain the anomalies recently reported by the D0
and CDF collaborations, namely the top forward-backward asymmetry (FBA), the
like-sign dimuon charge asymmetry in semileptonic b decay, and the CDF dijet
excess, has to feature an amount of flavor symmetry in order to satisfy the
severe constrains arising from flavor violation. In this paper we show that,
once baryon number conservation is imposed, color & weak triplet scalars with
hypercharge can feature the required flavor structure as a consequence
of standard model gauge invariance. The color & weak triplet model can
simultaneously explain the top FBA and the dimuon charge asymmetry or the
dimuon charge asymmetry and the CDF dijet excess. However, the CDF dijet excess
appears to be incompatible with the top FBA in the minimal framework. Our model
for the dimuon asymmetry predicts the observed pattern in the
region of parameter space required to explain the top FBA, whereas our model
for the CDF dijet anomaly is characterized by the absence of beyond the SM
b-quark jets in the excess region. Compatibility of the color & weak triplet
with the electroweak constraints is also discussed. We show that a Higgs boson
mass exceeding the LEP bound is typically favored in this scenario, and that
both Higgs production and decay can be significantly altered by the triplet.
The most promising collider signature is found if the splitting among the
components of the triplet is of weak scale magnitude.Comment: references added, published versio
The limited usefulness of real-time 3-dimensional echocardiography in obtaining normal reference ranges for right ventricular volumes
<p>Abstract</p> <p>Background</p> <p>To obtain normal reference ranges and intraobserver variability for right ventricular (RV) volume indexes (VI) and ejection fraction (EF) from apical recordings with real-time 3-dimensional echocardiography (RT3DE), and similarly for RV area indexes (AI) and area fraction (AF) with 2-dimensional echocardiography (2DE).</p> <p>Methods</p> <p>166 participants; 79 males and 87 females aged between 29–79 years and considered free from clinical and subclinical cardiovascular disease. Normal ranges are defined as 95% reference values and reproducibility as coefficients of variation (CV) for repeated measurements.</p> <p>Results</p> <p>None of the apical recordings with RT3DE and 2DE included the RV outflow tract. Upper reference values were 62 ml/m<sup>2 </sup>for RV end-diastolic (ED) VI and 24 ml/m<sup>2 </sup>for RV end-systolic (ES) VI. Lower normal reference value for RVEF was 41%. The respective reference ranges were 17 cm<sup>2</sup>/m<sup>2 </sup>for RVEDAI, 11 cm<sup>2</sup>/m<sup>2 </sup>for RVESAI and 27% for RVAF. Males had higher upper normal values for RVEDVI, RVESVI and RVEDAI, and a lower limit than females for RVEF and RVAF. Weak but significant negative correlations between age and RV dimensions were found with RT3DE, but not with 2DE. CVs for repeated measurements ranged between 10% and 14% with RT3DE and from 5% to 14% with 2DE.</p> <p>Conclusion</p> <p>Although the normal ranges for RVVIs and RVAIs presented in this study reflect RV inflow tract dimensions only, the data presented may still be regarded as a useful tool in clinical practice, especially for RVEF and RVAF.</p
Prioritizing the Role of Major Lipoproteins and Subfractions as Risk Factors for Peripheral Artery Disease.
BACKGROUND: Lipoprotein-related traits have been consistently identified as risk factors for atherosclerotic cardiovascular disease, largely on the basis of studies of coronary artery disease (CAD). The relative contributions of specific lipoproteins to the risk of peripheral artery disease (PAD) have not been well defined. We leveraged large-scale genetic association data to investigate the effects of circulating lipoprotein-related traits on PAD risk. METHODS: Genome-wide association study summary statistics for circulating lipoprotein-related traits were used in the mendelian randomization bayesian model averaging framework to prioritize the most likely causal major lipoprotein and subfraction risk factors for PAD and CAD. Mendelian randomization was used to estimate the effect of apolipoprotein B (ApoB) lowering on PAD risk using gene regions proxying lipid-lowering drug targets. Genes relevant to prioritized lipoprotein subfractions were identified with transcriptome-wide association studies. RESULTS: ApoB was identified as the most likely causal lipoprotein-related risk factor for both PAD (marginal inclusion probability, 0.86; P=0.003) and CAD (marginal inclusion probability, 0.92; P=0.005). Genetic proxies for ApoB-lowering medications were associated with reduced risk of both PAD (odds ratio,0.87 per 1-SD decrease in ApoB [95% CI, 0.84-0.91]; P=9×10-10) and CAD (odds ratio,0.66 [95% CI, 0.63-0.69]; P=4×10-73), with a stronger predicted effect of ApoB lowering on CAD (ratio of effects, 3.09 [95% CI, 2.29-4.60]; P<1×10-6). Extra-small very-low-density lipoprotein particle concentration was identified as the most likely subfraction associated with PAD risk (marginal inclusion probability, 0.91; P=2.3×10-4), whereas large low-density lipoprotein particle concentration was the most likely subfraction associated with CAD risk (marginal inclusion probability, 0.95; P=0.011). Genes associated with extra-small very-low-density lipoprotein particle and large low-density lipoprotein particle concentration included canonical ApoB pathway components, although gene-specific effects were variable. Lipoprotein(a) was associated with increased risk of PAD independently of ApoB (odds ratio, 1.04 [95% CI, 1.03-1.04]; P=1.0×10-33). CONCLUSIONS: ApoB was prioritized as the major lipoprotein fraction causally responsible for both PAD and CAD risk. However, ApoB-lowering drug targets and ApoB-containing lipoprotein subfractions had diverse associations with atherosclerotic cardiovascular disease, and distinct subfraction-associated genes suggest possible differences in the role of lipoproteins in the pathogenesis of PAD and CAD
New Physics Models of Direct CP Violation in Charm Decays
In view of the recent LHCb measurement of Delta A_CP, the difference between
the time-integrated CP asymmetries in D --> K+K- and D --> pi+pi- decays, we
perform a comparative study of the possible impact of New Physics degrees of
freedom on the direct CP asymmetries in singly Cabibbo suppressed D meson
decays. We systematically discuss scenarios with a minimal set of new degrees
of freedom that have renormalizable couplings to the SM particles and that are
heavy enough such that their effects on the D meson decays can be described by
local operators. We take into account both constraints from low energy flavor
observables, in particular D0-D0bar mixing, and from direct searches. While
models that explain the large measured value for Delta A_CP with chirally
enhanced chromomagnetic penguins are least constrained, we identify a few
viable models that contribute to the D meson decays at tree level or through
loop induced QCD penguins. We emphasize that such models motivate direct
searches at the LHC.Comment: 24 pages, 13 figures. v2: typos corrected, reference added, published
versio
Genetic Predisposition to an Impaired Metabolism of the Branched-Chain Amino Acids and Risk of Type 2 Diabetes: A Mendelian Randomisation Analysis
: Higher circulating levels of the branched-chain amino acids (BCAAs; i.e., isoleucine, leucine, and valine) are strongly associated with higher type 2 diabetes risk, but it is not known whether this association is causal. We undertook large-scale human genetic analyses to address this question.
: Genome-wide studies of BCAA levels in 16,596 individuals revealed five genomic regions associated at genome-wide levels of significance (p < 5 × 10-8). The strongest signal was 21 kb upstream of the PPM1K gene (beta in standard deviations [SDs] of leucine per allele = 0.08, p = 3.9 × 10-25), encoding an activator of the mitochondrial branched-chain alpha-ketoacid dehydrogenase (BCKD) responsible for the rate-limiting step in BCAA catabolism. In another analysis, in up to 47,877 cases of type 2 diabetes and 267,694 controls, a genetically predicted difference of 1 SD in amino acid level was associated with an odds ratio for type 2 diabetes of 1.44 (95% CI 1.26-1.65, p = 9.5 × 10-8) for isoleucine, 1.85 (95% CI 1.41-2.42, p = 7.3 × 10-6) for leucine, and 1.54 (95% CI 1.28-1.84, p = 4.2 × 10-6) for valine. Estimates were highly consistent with those from prospective observational studies of the association between BCAA levels and incident type 2 diabetes in a meta-analysis of 1,992 cases and 4,319 non-cases. Metabolome-wide association analyses of BCAA-raising alleles revealed high specificity to the BCAA pathway and an accumulation of metabolites upstream of branched-chain alpha-ketoacid oxidation, consistent with reduced BCKD activity. Limitations of this study are that, while the association of genetic variants appeared highly specific, the possibility of pleiotropic associations cannot be entirely excluded. Similar to other complex phenotypes, genetic scores used in the study captured a limited proportion of the heritability in BCAA levels. Therefore, it is possible that only some of the mechanisms that increase BCAA levels or affect BCAA metabolism are implicated in type 2 diabetes.
: Evidence from this large-scale human genetic and metabolomic study is consistent with a causal role of BCAA metabolism in the aetiology of type 2 diabetes.MRC Epidemiology Unit, Fenland study, EPIC-InterAct study, EPIC-Norfolk case-cohort study funding: this study was funded by the United Kingdom’s Medical Research Council through grants MC_UU_12015/1, MC_UU_12015/5, MC_PC_13046, MC_PC_13048 and MR/L00002/1. We acknowledge support from the National Institute for Health Research Biomedical Research Centre. The research leading to these results has received support from the Innovative Medicines Initiative Joint Undertaking under EMIF grant agreement number 115372, resources of which are composed of financial contribution from the European Union's Seventh Framework Programme (FP7/2007-2013) and EFPIA companies’ in kind contribution. EPIC-InterAct Study funding: funding for the InterAct project was provided by the EU FP6 programme (grant number LSHM_CT_2006_037197). MRC Human Nutrition Research funding: This research was supported by the Medical Research Council (MC_UP_A090_1006) and Cambridge Lipidomics Biomarker Research Initiative (G0800783). The SABRE study was funded at baseline by the UK Medical Research Council, Diabetes UK and the British Heart Foundation and at follow-up by a programme grant from the Wellcome Trust (WT082464) and British Heart Foundation (SP/07/001/23603); Diabetes UK funded the metabolomics analyses (13/0004774). RJOS, EN, JRZ and AK received funding from the Swedish Research Council, Stockholm County Council, Novo Nordisk Foundation and Diabetes Wellness. DBS is supported by the Wellcome Trust grant number 107064. MIM is a Wellcome Trust Senior Investigator and is supported by the following grants from the Wellcome Trust: 090532 and 098381. IB is supported by the Wellcome Trust grant WT098051
Endothelin receptor antagonist and airway dysfunction in pulmonary arterial hypertension
<p>Abstract</p> <p>Background</p> <p>In idiopathic pulmonary arterial hypertension (IPAH), peripheral airway obstruction is frequent. This is partially attributed to the mediator dysbalance, particularly an excess of endothelin-1 (ET-1), to increased pulmonary vascular and airway tonus and to local inflammation. Bosentan (ET-1 receptor antagonist) improves pulmonary hemodynamics, exercise limitation, and disease severity in IPAH. We hypothesized that bosentan might affect airway obstruction.</p> <p>Methods</p> <p>In 32 IPAH-patients (19 female, WHO functional class II (n = 10), III (n = 22); (data presented as mean ± standard deviation) pulmonary vascular resistance (11 ± 5 Wood units), lung function, 6 minute walk test (6-MWT; 364 ± 363.7 (range 179.0-627.0) m), systolic pulmonary artery pressure, sPAP, 79 ± 19 mmHg), and NT-proBNP serum levels (1427 ± 2162.7 (range 59.3-10342.0) ng/L) were measured at baseline, after 3 and 12 months of oral bosentan (125 mg twice per day).</p> <p>Results and Discussion</p> <p>At baseline, maximal expiratory flow at 50 and 25% vital capacity were reduced to 65 ± 25 and 45 ± 24% predicted. Total lung capacity was 95.6 ± 12.5% predicted and residual volume was 109 ± 21.4% predicted. During 3 and 12 months of treatment, 6-MWT increased by 32 ± 19 and 53 ± 69 m, respectively; p < 0.01; whereas sPAP decreased by 7 ± 14 and 10 ± 19 mmHg, respectively; p < 0.05. NT-proBNP serum levels tended to be reduced by 123 ± 327 and by 529 ± 1942 ng/L; p = 0.11). There was no difference in expiratory flows or lung volumes during 3 and 12 months.</p> <p>Conclusion</p> <p>This study gives first evidence in IPAH, that during long-term bosentan, improvement of hemodynamics, functional parameters or serum biomarker occur independently from persisting peripheral airway obstruction.</p
Genetic predisposition to an impaired metabolism of the branched-chain amino acids and risk of type 2 diabetes: a mendelian randomisation analysis
BACKGROUND: Higher circulating levels of the branched-chain amino acids (BCAAs; i.e., isoleucine, leucine, and valine) are strongly associated with higher type 2 diabetes risk, but it is not known whether this association is causal. We undertook large-scale human genetic analyses to address this question. METHODS AND FINDINGS: Genome-wide studies of BCAA levels in 16,596 individuals revealed five genomic regions associated at genome-wide levels of significance (p < 5 × 10-8). The strongest signal was 21 kb upstream of the PPM1K gene (beta in standard deviations [SDs] of leucine per allele = 0.08, p = 3.9 × 10-25), encoding an activator of the mitochondrial branched-chain alpha-ketoacid dehydrogenase (BCKD) responsible for the rate-limiting step in BCAA catabolism. In another analysis, in up to 47,877 cases of type 2 diabetes and 267,694 controls, a genetically predicted difference of 1 SD in amino acid level was associated with an odds ratio for type 2 diabetes of 1.44 (95% CI 1.26-1.65, p = 9.5 × 10-8) for isoleucine, 1.85 (95% CI 1.41-2.42, p = 7.3 × 10-6) for leucine, and 1.54 (95% CI 1.28-1.84, p = 4.2 × 10-6) for valine. Estimates were highly consistent with those from prospective observational studies of the association between BCAA levels and incident type 2 diabetes in a meta-analysis of 1,992 cases and 4,319 non-cases. Metabolome-wide association analyses of BCAA-raising alleles revealed high specificity to the BCAA pathway and an accumulation of metabolites upstream of branched-chain alpha-ketoacid oxidation, consistent with reduced BCKD activity. Limitations of this study are that, while the association of genetic variants appeared highly specific, the possibility of pleiotropic associations cannot be entirely excluded. Similar to other complex phenotypes, genetic scores used in the study captured a limited proportion of the heritability in BCAA levels. Therefore, it is possible that only some of the mechanisms that increase BCAA levels or affect BCAA metabolism are implicated in type 2 diabetes. CONCLUSIONS: Evidence from this large-scale human genetic and metabolomic study is consistent with a causal role of BCAA metabolism in the aetiology of type 2 diabetes
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