172 research outputs found

    How to project a bipartite network?

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    The one-mode projecting is extensively used to compress the bipartite networks. Since the one-mode projection is always less informative than the bipartite representation, a proper weighting method is required to better retain the original information. In this article, inspired by the network-based resource-allocation dynamics, we raise a weighting method, which can be directly applied in extracting the hidden information of networks, with remarkably better performance than the widely used global ranking method as well as collaborative filtering. This work not only provides a creditable method in compressing bipartite networks, but also highlights a possible way for the better solution of a long-standing challenge in modern information science: How to do personal recommendation?Comment: 7 pages, 4 figure

    Pollen exposure is associated with risk of respiratory symptoms during the first year of life.

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    BACKGROUND Pollen exposure is associated with respiratory symptoms in children and adults. However, the association of pollen exposure with respiratory symptoms during infancy, a particularly vulnerable period, remains unclear. We examined whether pollen exposure is associated with respiratory symptoms in infants and if maternal atopy, infant's sex or air pollution modify this association. METHODS We investigated 14,874 observations from 401 healthy infants of a prospective birth cohort. The association between pollen exposure and respiratory symptoms, assessed in weekly telephone interviews, was evaluated using generalized additive mixed models (GAMM). Effect modification by maternal atopy, infant's sex and air pollution (NO2 , PM2.5 ) was assessed with interaction terms. RESULTS Per infant 37±2 (mean±SD) respiratory symptom scores were assessed during the analysis period (January through September). Pollen exposure was associated with increased respiratory symptoms during the daytime (RR [95% CI] per 10% pollen/m3 : combined 1.006 [1.002, 1.009]; tree 1.005 [1.002, 1.008]; grass 1.009 [1.000, 1.23]) and nighttime (combined 1.003 [0.999, 1.007]; tree 1.003 [0.999, 1.007]; grass 1.014 [1.004, 1.024]). While there was no effect modification by maternal atopy and infant's sex, a complex crossover interaction between combined pollen and PM2.5 was found (p-Value 0.002). CONCLUSION Even as early as during the first year of life, pollen exposure was associated with an increased risk of respiratory symptoms, independent of maternal atopy and infant's sex. Because infancy is a particularly vulnerable period for lung development, the identified adverse effect of pollen exposure may be relevant for the evolvement of chronic childhood asthma

    A Systematic Approach to Multiple Breath Nitrogen Washout Test Quality

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    Background: Accurate estimates of multiple breath washout (MBW) outcomes require correct operation of the device, appropriate distraction of the subject to ensure they breathe in a manner representative of their relaxed tidal breathing pattern, and appropriate interpretation of the acquired data. Based on available recommendations for an acceptable MBW test, we aimed to develop a protocol to systematically evaluate MBW measurements based on these criteria. Methods: 50MBWtest occasions were systematically reviewed for technical elements and whether the breathing pattern was representative of relaxed tidal breathing by an experienced MBW operator. The impact of qualitative and quantitative criteria on inter-observer agreement was assessed across eight MBW operators (n = 20 test occasions, compared using a Kappa statistic). Results: Using qualitative criteria, 46/168 trials were rejected: 16.6%were technically unacceptable and 10.7% were excluded due to inappropriate breathing pattern. Reviewer agreement was good using qualitative criteria and further improved with quantitative criteria from (κ = 0.53– 0.83%) to (κ 0.73–0.97%), but at the cost of exclusion of further test occasions in this retrospective data analysis. Conclusions: The application of the systematic review improved inter-observer agreement but did not affect reported MBW outcomes

    A computerized tool for the systematic visual quality assessment of infant multiple-breath washout measurements

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    BackgroundMultiple-breath washout (MBW) is a sensitive method for assessing lung volumes and ventilation inhomogeneity in infants, but remains prone to artefacts (e.g., sighs). There is a lack of tools for systematic retrospective analysis of existing datasets, and unlike N2-MBW in older children, there are few specific quality control (QC) criteria for artefacts in infant SF6-MBW.AimWe aimed to develop a computer-based tool for systematic evaluation of visual QC criteria of SF6-MBW measurements and to investigate interrater agreement and effects on MBW outcomes among three independent examiners.MethodsWe developed a software package for visualization of raw Spiroware (Eco Medics AG, Switzerland) and signal processed WBreath (ndd Medizintechnik AG, Switzerland) SF6-MBW signal traces. Interrater agreement among three independent examiners (two experienced, one novice) who systematically reviewed 400 MBW trials for visual artefacts and the decision to accept/reject the washin and washout were assessed.ResultsOur tool visualizes MBW signals and provides the user with (i) display options (e.g., zoom), (ii) options for a systematic QC assessment [e.g., decision to accept or reject, identification of artefacts (leak, sigh, irregular breathing pattern, breath hold), and comments], and (iii) additional information (e.g., automatic identification of sighs). Reviewer agreement was good using pre-defined QC criteria (κ 0.637–0.725). Differences in the decision to accept/reject had no substantial effect on MBW outcomes.ConclusionOur visual quality control tool supports a systematic retrospective analysis of existing data sets. Based on predefined QC criteria, even inexperienced users can achieve comparable MBW results

    Supine posture changes lung volumes and increases ventilation heterogeneity in cystic fibrosis

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    INTRODUCTION: Lung Clearance Index (LCI) is recognised as an early marker of cystic fibrosis (CF) lung disease. The effect of posture on LCI however is important when considering longitudinal measurements from infancy and when comparing LCI to imaging studies. METHODS: 35 children with CF and 28 healthy controls (HC) were assessed. Multiple breath washout (MBW) was performed both sitting and supine in triplicate and analysed for LCI, Scond, Sacin, and lung volumes. These values were also corrected for the Fowler dead-space to create 'alveolar' indices. RESULTS: From sitting to supine there was a significant increase in LCI and a significant decrease in FRC for both CF and HC (p<0.01). LCI, when adjusted to estimate 'alveolar' LCI (LCIalv), increased the magnitude of change with posture for both LCIalv and FRCalv in both groups, with a greater effect of change in lung volume in HC compared with children with CF. The % change in LCIalv for all subjects correlated significantly with lung volume % changes, most notably tidal volume/functional residual capacity (Vtalv/FRCalv (r = 0.54,p<0.001)). CONCLUSION: There is a significant increase in LCI from sitting to supine, which we believe to be in part due to changes in lung volume and also increasing ventilation heterogeneity related to posture. This may have implications in longitudinal measurements from infancy to older childhood and for studies comparing supine imaging methods to LCI

    PI4K2A deficiency causes innate error in intracellular trafficking with developmental and epileptic-dyskinetic encephalopathy.

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    OBJECTIVE: Intracellular signaling networks rely on proper membrane organization to control an array of cellular processes such as metabolism, proliferation, apoptosis, and macroautophagy in eukaryotic cells and organisms. Phosphatidylinositol 4-phosphate (PI4P) emerged as an essential regulatory lipid within organelle membranes that defines their lipid composition and signaling properties. PI4P is generated by four distinct phosphatidylinositol 4-kinases (PI4K) in mammalian cells: PI4KA, PI4KB, PI4K2A, PI4K2B. Animal models and human genetic studies suggest vital roles of PI4K enzymes in development and function of various organs, including the nervous system. Bi-allelic variants in PI4KA were recently associated with neurodevelopmental disorders (NDD), brain malformations, leukodystrophy, primary immunodeficiency, and inflammatory bowel disease. Here, we describe patients from two unrelated consanguineous families with PI4K2A deficiency and functionally explored the pathogenic mechanism. METHODS: Two patients with PI4K2A deficiency were identified by exome sequencing, presenting with developmental and epileptic-dyskinetic encephalopathy. Neuroimaging showed corpus callosum dysgenesis, diffuse white matter volume loss, and hypoplastic vermis. In addition to NDD, we observed recurrent infections and death at toddler age. We further explored identified variants with cellular assays. RESULTS: This clinical presentation overlaps with what was previously reported in two affected siblings with homozygous nonsense PI4K2A variant. Cellular studies analyzing these human variants confirmed their deleterious effect on PI4K2A activity and, together with the central role of PI4K2A in Rab7-associated vesicular trafficking, establish a link between late endosome-lysosome defects and NDD. INTERPRETATION: Our study establishes the genotype-phenotype spectrum of PI4K-associated NDD and highlights several commonalities with other innate errors of intracellular trafficking

    Dietary fatty acids and endometrial cancer risk within the European Prospective Investigation into Cancer and Nutrition

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    BACKGROUND: Diet may impact important risk factors for endometrial cancer such as obesity and inflammation. However, evidence on the role of specific dietary factors is limited. We investigated associations between dietary fatty acids and endometrial cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC). METHODS: This analysis includes 1,886 incident endometrial cancer cases and 297,432 non-cases. All participants were followed up for a mean of 8.8 years. Multivariable Cox proportional hazard models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) of endometrial cancer across quintiles of individual fatty acids estimated from various food sources quantified through food frequency questionnaires in the entire EPIC cohort. The false discovery rate (q-values) was computed to control for multiple comparisons. RESULTS: Consumption of n-6 γ-linolenic acid was inversely associated with endometrial cancer risk (HR comparing 5th with 1st quintile Q5-Q1=0.77, 95% CI = 0.64; 0.92, p trend=0.01, q-value = 0.15). This association was mainly driven by γ-linolenic acid derived from plant sources (HR per unit increment=0.94, 95%CI= (0.90;0.98), p = 0.01) but not from animal sources (HR per unit increment= 1.00, 95%CI = (0.92; 1.07), p = 0.92). In addition, an inverse association was found between consumption of n-3 α-linolenic acid from vegetable sources and endometrial cancer risk (HR per unit increment= 0.93, 95%CI = (0.87; 0.99), p = 0.04). No significant association was found between any other fatty acids (individual or grouped) and endometrial cancer risk. CONCLUSION: Our results suggest that higher consumption of γ-linolenic acid and α-linoleic acid from plant sources may be associated with lower risk of endometrial cancer
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