3,148 research outputs found

    Vertex importance extension of betweenness centrality algorithm

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    Variety of real-life structures can be simplified by a graph. Such simplification emphasizes the structure represented by vertices connected via edges. A common method for the analysis of the vertices importance in a network is betweenness centrality. The centrality is computed using the information about the shortest paths that exist in a graph. This approach puts the importance on the edges that connect the vertices. However, not all vertices are equal. Some of them might be more important than others or have more significant influence on the behavior of the network. Therefore, we introduce the modification of the betweenness centrality algorithm that takes into account the vertex importance. This approach allows the further refinement of the betweenness centrality score to fulfill the needs of the network better. We show this idea on an example of the real traffic network. We test the performance of the algorithm on the traffic network data from the city of Bratislava, Slovakia to prove that the inclusion of the modification does not hinder the original algorithm much. We also provide a visualization of the traffic network of the city of Ostrava, the Czech Republic to show the effect of the vertex importance adjustment. The algorithm was parallelized by MPI (http://www.mpi-forum.org/) and was tested on the supercomputer Salomon (https://docs.it4i.cz/) at IT4Innovations National Supercomputing Center, the Czech Republic.808726

    Antipsychotics and Risk of Neuroleptic Malignant Syndrome: A Population-Based Cohort and Case-Crossover Study

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    BACKGROUND: Neuroleptic malignant syndrome (NMS) is a rare and acute adverse drug reaction associated with antipsychotic therapy. However, few data on the risk and epidemiology of NMS are available. OBJECTIVES: The aim of this study was to ascertain the incidence risk and all-cause mortality of NMS associated with antipsychotic use, and to assess the association of recent antipsychotic exposure and NMS. METHODS: We did a population-based study using data from the Hong Kong Hospital Authority’s Clinical Data Analysis and Reporting System database. Cases had a first diagnosis of NMS between 1 January 2004 and 30 November 2017. A case-crossover analysis was used to compare antipsychotic exposure 30 days before the diagnosis of NMS (index date) and a reference period 91–120 days before the index date. To adjust for potential time trends in antipsychotic exposure, we sampled from cases to match current cases and future cases, and further adjusted for select medications and acute medical conditions. RESULTS: 297,647 patients were prescribed antipsychotics, and the incidence risk of NMS was 0.11%. Of the 336 cases included in the case-crossover analysis, 20 (6%) died within 30 days after the index date; only one case had NMS recorded as the primary cause of death. When compared with the reference period, cases were more frequently prescribed multiple antipsychotics (15.8% vs 26.8%; standardized mean difference [SMD] 0.27) and short-acting injectable antipsychotics (3.6% vs 13.7%; SMD 0.37) during the 30 days prior to the diagnosis of NMS. Odds ratios for antipsychotic exposure in the case-crossover, case-crossover adjusted for time trend, and case-crossover adjusted for time trend and potential confounders analysis were 8.00 (95% confidence interval 3.42–18.69), 5.88 (2.46–14.04), and 4.77 (1.95–11.66). CONCLUSIONS: Our results suggest that recent use of antipsychotics is associated with NMS. Although a case-only design inherently controls for confounding by time-invariant factors, residual confounding by acute medical conditions with similar presentations to NMS cannot be fully excluded

    Global antiplatelet sales trend: A focus on P2Y12 inhibitors from 2008 to 2018

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    BACKGROUND: P2Y12 inhibitors are an important component of dual antiplatelet therapy. Yet, their accessibility and affordability across countries stratified by income levels have not been studied. METHODS: Sales data were retrieved from the IQVIA Multinational Integrated Data Analysis System for the description of P2Y12 inhibitors global sales. Countries were stratified into 38 high-income countries and 27 middle-income countries. RESULTS: Global sales of P2Y12 inhibitors increased from 0.80 SU per year per person in 2008 to 1.79 in 2018. Growth in sales of P2Y12 inhibitors was greater in middle-income countries compared to high-income countries. Clopidogrel had the highest sales volume in both high-income and middle-income countries from 2008 to 2018, while ticagrelor sales volume increased mainly in high-income countries. CONCLUSIONS: Despite current guideline recommendations favoring ticagrelor and prasugrel for the prevention of atherothrombotic complications in patients with an acute coronary syndrome, clopidogrel retained the highest sales volume among the P2Y12 inhibitors from 2008 to 2018

    Paclitaxel targets FOXM1 to regulate KIF20A in mitotic catastrophe and breast cancer paclitaxel resistance

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    FOXM1 has been implicated in taxane resistance, but the molecular mechanism involved remains elusive. In here, we show that FOXM1 depletion can sensitize breast cancer cells and mouse embryonic fibroblasts into entering paclitaxel-induced senescence, with the loss of clonogenic ability, and the induction of senescence-associated beta-galactosidase activity and flat cell morphology. We also demonstrate that FOXM1 regulates the expression of the microtubulin-associated kinesin KIF20A at the transcriptional level directly through a Forkhead response element (FHRE) in its promoter. Similar to FOXM1, KIF20A expression is downregulated by paclitaxel in the sensitive MCF-7 breast cancer cells and deregulated in the paclitaxel-resistant MCF-7TaxR cells. KIF20A depletion also renders MCF-7 and MCF-7TaxR cells more sensitive to paclitaxel-induced cellular senescence. Crucially, resembling paclitaxel treatment, silencing of FOXM1 and KIF20A similarly promotes abnormal mitotic spindle morphology and chromosome alignment, which have been shown to induce mitotic catastrophe-dependent senescence. The physiological relevance of the regulation of KIF20A by FOXM1 is further highlighted by the strong and significant correlations between FOXM1 and KIF20A expression in breast cancer patient samples. Statistical analysis reveals that both FOXM1 and KIF20A protein and mRNA expression significantly associates with poor survival, consistent with a role of FOXM1 and KIF20A in paclitaxel action and resistance. Collectively, our findings suggest that paclitaxel targets the FOXM1-KIF20A axis to drive abnormal mitotic spindle formation and mitotic catastrophe and that deregulated FOXM1 and KIF20A expression may confer paclitaxel resistance. These findings provide insights into the underlying mechanisms of paclitaxel resistance and have implications for the development of predictive biomarkers and novel chemotherapeutic strategies for paclitaxel resistance.Oncogene advance online publication, 11 May 2015; doi:10.1038/onc.2015.152.published_or_final_versio

    Relation of substance use disorders to mortality, accident and emergency department attendances, and hospital admissions: A 13-year population-based cohort study in Hong Kong

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    BACKGROUND: The impact of substance use disorders (SUD) in an Asian population has not been fully explored. We aimed to assess the risk of mortality, accident and emergency (A&E) department attendances, and hospital admissions associated with SUD in a population-based cohort study. METHOD: Patients diagnosed with SUD in public A&E departments from 2004 to 2016 (N = 8,423) were identified in the Clinical Database Analysis and Reporting System of the Hong Kong Hospital Authority and 1:1 matched to patients without SUD by propensity score (N = 6,074 in each group). Relative risks of mortality, A&E attendances and hospital admissions were assessed using Cox regression and Hurdle negative binomial regression. RESULTS: Patients with SUD had higher mortality (hazard ratio=1.43; 95% confidence interval [CI]=1.26-1.62) and more often died from poisoning or toxicity and injuries. The odds ratio (OR) for A&E attendances and all-cause hospital admissions associated with SUD were 2.80 (95% CI=2.58-3.04) and 3.54 (95% CI=3.26-3.83), respectively. The impact of SUD on the above outcomes was greatest among school-aged individuals (≤ 21 years) and decreased with age. The relative risk of mental disorder-related hospital admissions was much higher than that for infections, respiratory diseases, and cardiovascular diseases. In patients with SUD, ketamine and amphetamine use were associated with increased A&E attendances than opioid use. CONCLUSIONS: SUD was associated with increased mortality, A&E attendances and hospital admissions, especially in school-aged individuals. Our findings suggest prioritising early treatment and preventive interventions for school-aged individuals and focusing on the management of comorbid mental disorders and the use of ketamine and amphetamine

    Association Between Non-vitamin K Antagonist Oral Anticoagulants or Warfarin and Liver Injury: A Cohort Study

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    INTRODUCTION: The risk of liver injury in patients with atrial fibrillation (AF) using nonvitamin K antagonist oral anticoagulants (NOACs) has not been previously examined using liver function tests as the primary outcome in the real-world setting. This study assessed the association between NOACs (dabigatran, rivaroxaban, and apixaban) and warfarin and the risk of liver injury, as defined by laboratory tests. METHODS: Patients newly diagnosed with AF and prescribed NOACs or warfarin between 2010 and 2016, identified using the Hong Kong Clinical Database and Reporting System, were matched on age, sex, health status scores, comorbidities, and medications by propensity score on a 1:1 ratio. Risk of liver injury, defined as laboratory test values >3 times the upper limit of normal of alanine aminotransferase or aspartate aminotransferase and >2 times the upper limit of normal of total bilirubin, was compared between NOAC and warfarin users using Cox proportional hazards regression. RESULTS: After propensity score matching, 13,698 patients were included, of which 141 (2.1%) NOAC users and 232 (3.4%) warfarin users developed liver injury. The hazard ratio (HR) for NOAC vs warfarin users was 0.71 (95% confidence interval: 0.58–0.89). When comparing individual NOACs, only dabigatran (hazard ratio: 0.63; 95% confidence interval: 0.48–0.82) was associated with a lower risk of liver injury. DISCUSSION: Among patients with AF, NOACs as a group, and dabigatran alone were associated with a significantly lower risk of laboratory-based liver injury when compared with warfarin. However, liver injury occurs more frequently in real-world practice than in NOAC randomized controlled trials

    Echinoderms have bilateral tendencies

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    Echinoderms take many forms of symmetry. Pentameral symmetry is the major form and the other forms are derived from it. However, the ancestors of echinoderms, which originated from Cambrian period, were believed to be bilaterians. Echinoderm larvae are bilateral during their early development. During embryonic development of starfish and sea urchins, the position and the developmental sequence of each arm are fixed, implying an auxological anterior/posterior axis. Starfish also possess the Hox gene cluster, which controls symmetrical development. Overall, echinoderms are thought to have a bilateral developmental mechanism and process. In this article, we focused on adult starfish behaviors to corroborate its bilateral tendency. We weighed their central disk and each arm to measure the position of the center of gravity. We then studied their turning-over behavior, crawling behavior and fleeing behavior statistically to obtain the center of frequency of each behavior. By joining the center of gravity and each center of frequency, we obtained three behavioral symmetric planes. These behavioral bilateral tendencies might be related to the A/P axis during the embryonic development of the starfish. It is very likely that the adult starfish is, to some extent, bilaterian because it displays some bilateral propensity and has a definite behavioral symmetric plane. The remainder of bilateral symmetry may have benefited echinoderms during their evolution from the Cambrian period to the present

    Fully gapped topological surface states in Bi2_2Se3_3 films induced by a d-wave high-temperature superconductor

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    Topological insulators are a new class of materials, that exhibit robust gapless surface states protected by time-reversal symmetry. The interplay between such symmetry-protected topological surface states and symmetry-broken states (e.g. superconductivity) provides a platform for exploring novel quantum phenomena and new functionalities, such as 1D chiral or helical gapless Majorana fermions, and Majorana zero modes which may find application in fault-tolerant quantum computation. Inducing superconductivity on topological surface states is a prerequisite for their experimental realization. Here by growing high quality topological insulator Bi2_2Se3_3 films on a d-wave superconductor Bi2_2Sr2_2CaCu2_2O8+δ_{8+\delta} using molecular beam epitaxy, we are able to induce high temperature superconductivity on the surface states of Bi2_2Se3_3 films with a large pairing gap up to 15 meV. Interestingly, distinct from the d-wave pairing of Bi2_2Sr2_2CaCu2_2O8+δ_{8+\delta}, the proximity-induced gap on the surface states is nearly isotropic and consistent with predominant s-wave pairing as revealed by angle-resolved photoemission spectroscopy. Our work could provide a critical step toward the realization of the long sought-after Majorana zero modes.Comment: Nature Physics, DOI:10.1038/nphys274

    Surface and Temporal Biosignatures

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    Recent discoveries of potentially habitable exoplanets have ignited the prospect of spectroscopic investigations of exoplanet surfaces and atmospheres for signs of life. This chapter provides an overview of potential surface and temporal exoplanet biosignatures, reviewing Earth analogues and proposed applications based on observations and models. The vegetation red-edge (VRE) remains the most well-studied surface biosignature. Extensions of the VRE, spectral "edges" produced in part by photosynthetic or nonphotosynthetic pigments, may likewise present potential evidence of life. Polarization signatures have the capacity to discriminate between biotic and abiotic "edge" features in the face of false positives from band-gap generating material. Temporal biosignatures -- modulations in measurable quantities such as gas abundances (e.g., CO2), surface features, or emission of light (e.g., fluorescence, bioluminescence) that can be directly linked to the actions of a biosphere -- are in general less well studied than surface or gaseous biosignatures. However, remote observations of Earth's biosphere nonetheless provide proofs of concept for these techniques and are reviewed here. Surface and temporal biosignatures provide complementary information to gaseous biosignatures, and while likely more challenging to observe, would contribute information inaccessible from study of the time-averaged atmospheric composition alone.Comment: 26 pages, 9 figures, review to appear in Handbook of Exoplanets. Fixed figure conversion error
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