77 research outputs found

    Widest Paths and Global Propagation in Bounded Value Iteration for Stochastic Games

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    Solving stochastic games with the reachability objective is a fundamental problem, especially in quantitative verification and synthesis. For this purpose, bounded value iteration (BVI) attracts attention as an efficient iterative method. However, BVI's performance is often impeded by costly end component (EC) computation that is needed to ensure convergence. Our contribution is a novel BVI algorithm that conducts, in addition to local propagation by the Bellman update that is typical of BVI, global propagation of upper bounds that is not hindered by ECs. To conduct global propagation in a computationally tractable manner, we construct a weighted graph and solve the widest path problem in it. Our experiments show the algorithm's performance advantage over the previous BVI algorithms that rely on EC computation.Comment: v2: an URL to the implementation is adde

    Quantitative Analysis of Single Nucleotide Polymorphisms within Copy Number Variation

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    BACKGROUND: Single nucleotide polymorphisms (SNPs) have been used extensively in genetics and epidemiology studies. Traditionally, SNPs that did not pass the Hardy-Weinberg equilibrium (HWE) test were excluded from these analyses. Many investigators have addressed possible causes for departure from HWE, including genotyping errors, population admixture and segmental duplication. Recent large-scale surveys have revealed abundant structural variations in the human genome, including copy number variations (CNVs). This suggests that a significant number of SNPs must be within these regions, which may cause deviation from HWE. RESULTS: We performed a Bayesian analysis on the potential effect of copy number variation, segmental duplication and genotyping errors on the behavior of SNPs. Our results suggest that copy number variation is a major factor of HWE violation for SNPs with a small minor allele frequency, when the sample size is large and the genotyping error rate is 0~1%. CONCLUSIONS: Our study provides the posterior probability that a SNP falls in a CNV or a segmental duplication, given the observed allele frequency of the SNP, sample size and the significance level of HWE testing

    The impact of emotional well-being on long-term recovery and survival in physical illness: a meta-analysis

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    This meta-analysis synthesized studies on emotional well-being as predictor of the prognosis of physical illness, while in addition evaluating the impact of putative moderators, namely constructs of well-being, health-related outcome, year of publication, follow-up time and methodological quality of the included studies. The search in reference lists and electronic databases (Medline and PsycInfo) identified 17 eligible studies examining the impact of general well-being, positive affect and life satisfaction on recovery and survival in physically ill patients. Meta-analytically combining these studies revealed a Likelihood Ratio of 1.14, indicating a small but significant effect. Higher levels of emotional well-being are beneficial for recovery and survival in physically ill patients. The findings show that emotional well-being predicts long-term prognosis of physical illness. This suggests that enhancement of emotional well-being may improve the prognosis of physical illness, which should be investigated by future research

    Psychiatric disorder in early adulthood and risk of premature mortality in the 1946 British Birth Cohort

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    <p>Abstract</p> <p>Background</p> <p>Few studies of the association between psychiatric disorder and premature death have adjusted for key confounders and used structured psychiatric interviews. We aimed to investigate if psychiatric disorder was associated with a higher risk of mortality and whether any excess mortality was due to suicide, or explained by other health or socioeconomic risk factors.</p> <p>Methods</p> <p>We used data from the MRC National Survey of Health and Development, a nationally representative UK birth cohort. 3283 men and women completed the Present State Examination at age 36. The main outcome measure was all-cause mortality before age 60.</p> <p>Results</p> <p>Those with psychiatric disorder at age 36 had a higher risk of death even after adjusting for potential confounders (Hazard ratio = 1.84, 95% C.I. 1.22-2.78). Censoring violent deaths and suicides led to similar results.</p> <p>Conclusions</p> <p>Psychiatric disorder was associated with excess premature mortality not explained by suicide or other health or socioeconomic risk factors.</p

    Comprehensive assessment of sequence variation within the copy number variable defensin cluster on 8p23 by target enriched in-depth 454 sequencing

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    <p>Abstract</p> <p>Background</p> <p>In highly copy number variable (CNV) regions such as the human defensin gene locus, comprehensive assessment of sequence variations is challenging. PCR approaches are practically restricted to tiny fractions, and next-generation sequencing (NGS) approaches of whole individual genomes e.g. by the 1000 Genomes Project is confined by an affordable sequence depth. Combining target enrichment with NGS may represent a feasible approach.</p> <p>Results</p> <p>As a proof of principle, we enriched a ~850 kb section comprising the CNV defensin gene cluster DEFB, the invariable DEFA part and 11 control regions from two genomes by sequence capture and sequenced it by 454 technology. 6,651 differences to the human reference genome were found. Comparison to HapMap genotypes revealed sensitivities and specificities in the range of 94% to 99% for the identification of variations.</p> <p>Using error probabilities for rigorous filtering revealed 2,886 unique single nucleotide variations (SNVs) including 358 putative novel ones. DEFB CN determinations by haplotype ratios were in agreement with alternative methods.</p> <p>Conclusion</p> <p>Although currently labor extensive and having high costs, target enriched NGS provides a powerful tool for the comprehensive assessment of SNVs in highly polymorphic CNV regions of individual genomes. Furthermore, it reveals considerable amounts of putative novel variations and simultaneously allows CN estimation.</p

    Impaired Phagocytosis in Localized Aggressive Periodontitis: Rescue by Resolvin E1

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    Resolution of inflammation is an active temporally orchestrated process demonstrated by the biosynthesis of novel proresolving mediators. Dysregulation of resolution pathways may underlie prevalent human inflammatory diseases such as cardiovascular diseases and periodontitis. Localized Aggressive Periodontitis (LAP) is an early onset, rapidly progressing form of inflammatory periodontal disease. Here, we report increased surface P-selectin on circulating LAP platelets, and elevated integrin (CD18) surface expression on neutrophils and monocytes compared to healthy, asymptomatic controls. Significantly more platelet-neutrophil and platelet-monocyte aggregates were identified in circulating whole blood of LAP patients compared with asymptomatic controls. LAP whole blood generates increased pro-inflammatory LTB4 with addition of divalent cation ionophore A23187 (5 µM) and significantly less, 15-HETE, 12-HETE, 14-HDHA, and lipoxin A4. Macrophages from LAP subjects exhibit reduced phagocytosis. The pro-resolving lipid mediator, Resolvin E1 (0.1–100 nM), rescues the impaired phagocytic activity in LAP macrophages. These abnormalities suggest compromised resolution pathways, which may contribute to persistent inflammation resulting in establishment of a chronic inflammatory lesion and periodontal disease progression

    Ganglioside composition and histology of a spontaneous metastatic brain tumour in the VM mouse

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    Glycosphingolipid abnormalities have long been implicated in tumour malignancy and metastasis. Gangliosides are a family of sialic acid-containing glycosphingolipids that modulate cell–cell and cell–matrix interactions. Histology and ganglioside composition were examined in a natural brain tumour of the VM mouse strain. The tumour is distinguished from other metastatic tumour models because it arose spontaneously and metastasizes to several organs including brain and spinal cord after subcutaneous inoculation of tumour tissue in the flank. By electron microscopy, the tumour consisted of cells (15 to 20 μm in diameter) that had slightly indented nuclei and scant cytoplasm. The presence of smooth membranes with an absence of junctional complexes was a characteristic ultrastructural feature. No positive immunostaining was found for glial or neuronal markers. The total ganglioside sialic acid content of the subcutaneously grown tumour was low (12.6 ± 0.9 μg per 100 mg dry wt, n= 6 separate tumours) and about 70% of this was in the form of N-glycolylneuraminic acid. In contrast, the ganglioside content of the cultured VM tumour cells was high (248.4 ± 4.4 μg, n= 3) and consisted almost exclusively of N-acetylneuraminic acid. The ganglioside pattern of the tumour grown subcutaneously was complex, while GM3, GM2, GM1, and GD1a were the major gangliosides in the cultured tumour cells. This tumour will be a useful natural model for evaluating the role of gangliosides and other glycolipids in tumour cell invasion and metastasis. © 2001 Cancer Research Campaign http://www.bjcancer.co

    The restorative role of annexin A1 at the blood–brain barrier

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    Annexin A1 is a potent anti-inflammatory molecule that has been extensively studied in the peripheral immune system, but has not as yet been exploited as a therapeutic target/agent. In the last decade, we have undertaken the study of this molecule in the central nervous system (CNS), focusing particularly on the primary interface between the peripheral body and CNS: the blood–brain barrier. In this review, we provide an overview of the role of this molecule in the brain, with a particular emphasis on its functions in the endothelium of the blood–brain barrier, and the protective actions the molecule may exert in neuroinflammatory, neurovascular and metabolic disease. We focus on the possible new therapeutic avenues opened up by an increased understanding of the role of annexin A1 in the CNS vasculature, and its potential for repairing blood–brain barrier damage in disease and aging

    Resolution of inflammation: a new therapeutic frontier

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    Dysregulated inflammation is a central pathological process in diverse disease states. Traditionally, therapeutic approaches have sought to modulate the pro- or anti-inflammatory limbs of inflammation, with mixed success. However, insight into the pathways by which inflammation is resolved has highlighted novel opportunities to pharmacologically manipulate these processes — a strategy that might represent a complementary (and perhaps even superior) therapeutic approach. This Review discusses the state of the art in the biology of resolution of inflammation, highlighting the opportunities and challenges for translational research in this field

    A common copy-number breakpoint of ERBB2 amplification in breast cancer colocalizes with a complex block of segmental duplications

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