87 research outputs found

    An Analysis of Pressure Fluctuations in a CFB of Heavy Minerals

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    Pressure fluctuations were measured at high frequencies in a CFB model operated with air at ambient conditions. The model comprises an 80-mm-ID, 5-m-tall riser with a blind-T exit, a cyclone, a 50-mm-ID standpipe, and an L-valve. Tests were conducted with particles of natural rutile (TiO2), a heavy mineral mined from coastal dunes. The particles fall into group B of Geldart’s classification. The solids inventory was kept at 25 kg. The superficial gas velocity ranged from 3 to 6 m/s. The solid circulation flux varied between 10 and 40 kg/m2.s. Profiles of solid concentrations in the riser are C-shaped. The amplitude of pressure fluctuations increases with increasing solids-circulation rate, and the increase appears to be linear. The amplitude does not correlate with solids concentration, however. The implication is that gas-solid interactions differ significantly at the bottom and the top of the riser, despite similar solids concentrations in these two zones. The analysis in the frequency domain shows that the power of signals resides in those of low frequencies (less than 2 Hz). The pressure fluctuations reflect white noise: there is no dominant frequency and no periodic component. Pressure waves move at 25–45 m/s up the riser, an order of magnitude greater than the superficial gas velocity

    Evaluation of ear, nose, and throat-screening in liver transplantation candidates:A retrospective cohort study

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    Background:Patients with end-stage liver disease can be treated with a liver transplantation (LT). Before listing, candidates are subjected to a screening procedure according to the EASL Clinical Practice Guidelines for LT. In our hospital, this includes an ear, nose, and throat (ENT) examination, directed towards the identification of (asymptomatic) infections and head and neck malignancies.Methods:We retrospectively reviewed all ENT screening examinations in LT candidates from 2007 to 2022. The screening consisted of a visit to the ENT outpatient clinic combined with sinus radiography.Results:ENT screening was performed in 1099 patients. Sixty-one cases were identified, either diagnosed with an infection (n = 58, almost exclusively sinusitis) or a neoplasm (n = 3, of which two malignancies). With binary logistic regression, we could not identify significant risk factors for diagnosing sinusitis. 711 patients underwent LT. After LT, two patients developed a novel malignancy of the head and neck area, while 14 patients were diagnosed with sinusitis, two of the latter already showed opacification on sinus radiography during screening. Despite immunosuppressive drugs, no complicated sinusitis was observed.Conclusion:Sinusitis or a neoplasm was diagnosed in almost 6% in a large cohort of LT candidates. Although almost a third of sinusitis patients were not treated accordingly, we did not observe any complicated sinusitis after LT. A more conservative approach to sinusitis may therefore be justified in LT candidates, especially in asymptomatic cases. At our institution, we aim to refer only those patients with specific ENT complaintsimage.This study aimed to evaluate the outcome of routine ear, nose, and throat screening in a large cohort of liver transplantation candidates. Note that, 6% were diagnosed with either sinusitis or a neoplasm. We did not observe any complicated sinusitis after transplantation. A more conservative approach may therefore be justified, especially in asymptomatic cases.imag

    Evaluation of ear, nose, and throat-screening in liver transplantation candidates:A retrospective cohort study

    Get PDF
    Background:Patients with end-stage liver disease can be treated with a liver transplantation (LT). Before listing, candidates are subjected to a screening procedure according to the EASL Clinical Practice Guidelines for LT. In our hospital, this includes an ear, nose, and throat (ENT) examination, directed towards the identification of (asymptomatic) infections and head and neck malignancies.Methods:We retrospectively reviewed all ENT screening examinations in LT candidates from 2007 to 2022. The screening consisted of a visit to the ENT outpatient clinic combined with sinus radiography.Results:ENT screening was performed in 1099 patients. Sixty-one cases were identified, either diagnosed with an infection (n = 58, almost exclusively sinusitis) or a neoplasm (n = 3, of which two malignancies). With binary logistic regression, we could not identify significant risk factors for diagnosing sinusitis. 711 patients underwent LT. After LT, two patients developed a novel malignancy of the head and neck area, while 14 patients were diagnosed with sinusitis, two of the latter already showed opacification on sinus radiography during screening. Despite immunosuppressive drugs, no complicated sinusitis was observed.Conclusion:Sinusitis or a neoplasm was diagnosed in almost 6% in a large cohort of LT candidates. Although almost a third of sinusitis patients were not treated accordingly, we did not observe any complicated sinusitis after LT. A more conservative approach to sinusitis may therefore be justified in LT candidates, especially in asymptomatic cases. At our institution, we aim to refer only those patients with specific ENT complaintsimage.This study aimed to evaluate the outcome of routine ear, nose, and throat screening in a large cohort of liver transplantation candidates. Note that, 6% were diagnosed with either sinusitis or a neoplasm. We did not observe any complicated sinusitis after transplantation. A more conservative approach may therefore be justified, especially in asymptomatic cases.imag

    Genetic association study of QT interval highlights role for calcium signaling pathways in myocardial repolarization.

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    The QT interval, an electrocardiographic measure reflecting myocardial repolarization, is a heritable trait. QT prolongation is a risk factor for ventricular arrhythmias and sudden cardiac death (SCD) and could indicate the presence of the potentially lethal mendelian long-QT syndrome (LQTS). Using a genome-wide association and replication study in up to 100,000 individuals, we identified 35 common variant loci associated with QT interval that collectively explain ∼8-10% of QT-interval variation and highlight the importance of calcium regulation in myocardial repolarization. Rare variant analysis of 6 new QT interval-associated loci in 298 unrelated probands with LQTS identified coding variants not found in controls but of uncertain causality and therefore requiring validation. Several newly identified loci encode proteins that physically interact with other recognized repolarization proteins. Our integration of common variant association, expression and orthogonal protein-protein interaction screens provides new insights into cardiac electrophysiology and identifies new candidate genes for ventricular arrhythmias, LQTS and SCD

    Genetic insights into resting heart rate and its role in cardiovascular disease

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    Resting heart rate is associated with cardiovascular diseases and mortality in observational and Mendelian randomization studies. The aims of this study are to extend the number of resting heart rate associated genetic variants and to obtain further insights in resting heart rate biology and its clinical consequences. A genome-wide meta-analysis of 100 studies in up to 835,465 individuals reveals 493 independent genetic variants in 352 loci, including 68 genetic variants outside previously identified resting heart rate associated loci. We prioritize 670 genes and in silico annotations point to their enrichment in cardiomyocytes and provide insights in their ECG signature. Two-sample Mendelian randomization analyses indicate that higher genetically predicted resting heart rate increases risk of dilated cardiomyopathy, but decreases risk of developing atrial fibrillation, ischemic stroke, and cardio-embolic stroke. We do not find evidence for a linear or non-linear genetic association between resting heart rate and all-cause mortality in contrast to our previous Mendelian randomization study. Systematic alteration of key differences between the current and previous Mendelian randomization study indicates that the most likely cause of the discrepancy between these studies arises from false positive findings in previous one-sample MR analyses caused by weak-instrument bias at lower P-value thresholds. The results extend our understanding of resting heart rate biology and give additional insights in its role in cardiovascular disease development.</p

    The Diagnostic Potential of Fe Lines Applied to Protostellar Jets

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    We investigate the diagnostic capabilities of iron lines for tracing the physical conditions of shock-excited gas in jets driven by pre-main sequence stars. We have analyzed the 3000-25000 \uc5, X-shooter spectra of two jets driven by the pre-main sequence stars ESO-H\u3b1 574 and Par-Lup 3-4. Both spectra are very rich in [Fe II] lines over the whole spectral range; in addition, lines from [Fe III] are detected in the ESO-H\u3b1 574 spectrum. Non-local thermal equilibrium codes solving the equations of the statistical equilibrium along with codes for the ionization equilibrium are used to derive the gas excitation conditions of electron temperature and density and fractional ionization. An estimate of the iron gas-phase abundance is provided by comparing the iron lines emissivity with that of neutral oxygen at 6300 \uc5. The [Fe II] line analysis indicates that the jet driven by ESO-H\u3b1 574 is, on average, colder (T e 3c 9000 K), less dense (n e 3c 2 7 104 cm-3), and more ionized (x e 3c 0.7) than the Par-Lup 3-4 jet (T e 3c 13,000 K, n e 3c 6 7 104 cm-3, x e < 0.4), even if the existence of a higher density component (n e 3c 2 7 105 cm-3) is probed by the [Fe III] and [Fe II] ultra-violet lines. The physical conditions derived from the iron lines are compared with shock models suggesting that the shock at work in ESO-H\u3b1 574 is faster and likely more energetic than the Par-Lup 3-4 shock. This latter feature is confirmed by the high percentage of gas-phase iron measured in ESO-H\u3b1 574 (50%-60% of its solar abundance in comparison with less than 30% in Par-Lup 3-4), which testifies that the ESO-H\u3b1 574 shock is powerful enough to partially destroy the dust present inside the jet. This work demonstrates that a multiline Fe analysis can be effectively used to probe the excitation and ionization conditions of the gas in a jet without any assumption on ionic abundances. The main limitation on the diagnostics resides in the large uncertainties of the atomic data, which, however, can be overcome through a statistical approach involving many line

    Genome-wide analysis identifies genetic effects on reproductive success and ongoing natural selection at the FADS locus

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    : Identifying genetic determinants of reproductive success may highlight mechanisms underlying fertility and identify alleles under present-day selection. Using data in 785,604 individuals of European ancestry, we identified 43 genomic loci associated with either number of children ever born (NEB) or childlessness. These loci span diverse aspects of reproductive biology, including puberty timing, age at first birth, sex hormone regulation, endometriosis and age at menopause. Missense variants in ARHGAP27 were associated with higher NEB but shorter reproductive lifespan, suggesting a trade-off at this locus between reproductive ageing and intensity. Other genes implicated by coding variants include PIK3IP1, ZFP82 and LRP4, and our results suggest a new role for the melanocortin 1 receptor (MC1R) in reproductive biology. As NEB is one component of evolutionary fitness, our identified associations indicate loci under present-day natural selection. Integration with data from historical selection scans highlighted an allele in the FADS1/2 gene locus that has been under selection for thousands of years and remains so today. Collectively, our findings demonstrate that a broad range of biological mechanisms contribute to reproductive success

    Identification of additional risk loci for stroke and small vessel disease: a meta-analysis of genome-wide association studies

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    BACKGROUND: Genetic determinants of stroke, the leading neurological cause of death and disability, are poorly understood and have seldom been explored in the general population. Our aim was to identify additional loci for stroke by doing a meta-analysis of genome-wide association studies. METHODS: For the discovery sample, we did a genome-wide analysis of common genetic variants associated with incident stroke risk in 18 population-based cohorts comprising 84 961 participants, of whom 4348 had stroke. Stroke diagnosis was ascertained and validated by the study investigators. Mean age at stroke ranged from 45·8 years to 76·4 years, and data collection in the studies took place between 1948 and 2013. We did validation analyses for variants yielding a significant association (at p<5 × 10(-6)) with all-stroke, ischaemic stroke, cardioembolic ischaemic stroke, or non-cardioembolic ischaemic stroke in the largest available cross-sectional studies (70 804 participants, of whom 19 816 had stroke). Summary-level results of discovery and follow-up stages were combined using inverse-variance weighted fixed-effects meta-analysis, and in-silico lookups were done in stroke subtypes. For genome-wide significant findings (at p<5 × 10(-8)), we explored associations with additional cerebrovascular phenotypes and did functional experiments using conditional (inducible) deletion of the probable causal gene in mice. We also studied the expression of orthologs of this probable causal gene and its effects on cerebral vasculature in zebrafish mutants. FINDINGS: We replicated seven of eight known loci associated with risk for ischaemic stroke, and identified a novel locus at chromosome 6p25 (rs12204590, near FOXF2) associated with risk of all-stroke (odds ratio [OR] 1·08, 95% CI 1·05-1·12, p=1·48 × 10(-8); minor allele frequency 21%). The rs12204590 stroke risk allele was also associated with increased MRI-defined burden of white matter hyperintensity-a marker of cerebral small vessel disease-in stroke-free adults (n=21 079; p=0·0025). Consistently, young patients (aged 2-32 years) with segmental deletions of FOXF2 showed an extensive burden of white matter hyperintensity. Deletion of Foxf2 in adult mice resulted in cerebral infarction, reactive gliosis, and microhaemorrhage. The orthologs of FOXF2 in zebrafish (foxf2b and foxf2a) are expressed in brain pericytes and mutant foxf2b(-/-) cerebral vessels show decreased smooth muscle cell and pericyte coverage. INTERPRETATION: We identified common variants near FOXF2 that are associated with increased stroke susceptibility. Epidemiological and experimental data suggest that FOXF2 mediates this association, potentially via differentiation defects of cerebral vascular mural cells. Further expression studies in appropriate human tissues, and further functional experiments with long follow-up periods are needed to fully understand the underlying mechanisms

    Genome-wide analysis identifies 12 loci influencing human reproductive behavior.

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    The genetic architecture of human reproductive behavior-age at first birth (AFB) and number of children ever born (NEB)-has a strong relationship with fitness, human development, infertility and risk of neuropsychiatric disorders. However, very few genetic loci have been identified, and the underlying mechanisms of AFB and NEB are poorly understood. We report a large genome-wide association study of both sexes including 251,151 individuals for AFB and 343,072 individuals for NEB. We identified 12 independent loci that are significantly associated with AFB and/or NEB in a SNP-based genome-wide association study and 4 additional loci associated in a gene-based effort. These loci harbor genes that are likely to have a role, either directly or by affecting non-local gene expression, in human reproduction and infertility, thereby increasing understanding of these complex traits
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