118 research outputs found

    Machine prognostics based on health state estimation using SVM

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    The ability to accurately predict the remaining useful life of machine components is critical for continuous operations in machines which can also improve productivity and enhance system safety. In condition-based maintenance (CBM), effective diagnostics and prognostics are important aspects of CBM which provide sufficient time for maintenance engineers to schedule a repair and acquire replacement components before the components finally fail. All machine components have certain characteristics of failure patterns and are subjected to degradation processes in real environments. This paper describes a technique for accurate assessment of the remnant life of machines based on prior expert knowledge embedded in closed loop prognostics systems. The technique uses Support Vector Machines (SVM) for classification of faults and evaluation of health for six stages of bearing degradation. To validate the feasibility of the proposed model, several fault historical data from High Pressure Liquefied Natural Gas (LNG) pumps were analysed to obtain their failure patterns. The results obtained were very encouraging and the prediction closely matched the real life particularly at the end of term of the bearings

    Text mining of full-text journal articles combined with gene expression analysis reveals a relationship between sphingosine-1-phosphate and invasiveness of a glioblastoma cell line

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    BACKGROUND: Sphingosine 1-phosphate (S1P), a lysophospholipid, is involved in various cellular processes such as migration, proliferation, and survival. To date, the impact of S1P on human glioblastoma is not fully understood. Particularly, the concerted role played by matrix metalloproteinases (MMP) and S1P in aggressive tumor behavior and angiogenesis remains to be elucidated. RESULTS: To gain new insights in the effect of S1P on angiogenesis and invasion of this type of malignant tumor, we used microarrays to investigate the gene expression in glioblastoma as a response to S1P administration in vitro. We compared the expression profiles for the same cell lines under the influence of epidermal growth factor (EGF), an important growth factor. We found a set of 72 genes that are significantly differentially expressed as a unique response to S1P. Based on the result of mining full-text articles from 20 scientific journals in the field of cancer research published over a period of five years, we inferred gene-gene interaction networks for these 72 differentially expressed genes. Among the generated networks, we identified a particularly interesting one. It describes a cascading event, triggered by S1P, leading to the transactivation of MMP-9 via neuregulin-1 (NRG-1), vascular endothelial growth factor (VEGF), and the urokinase-type plasminogen activator (uPA). This interaction network has the potential to shed new light on our understanding of the role played by MMP-9 in invasive glioblastomas. CONCLUSION: Automated extraction of information from biological literature promises to play an increasingly important role in biological knowledge discovery. This is particularly true for high-throughput approaches, such as microarrays, and for combining and integrating data from different sources. Text mining may hold the key to unraveling previously unknown relationships between biological entities and could develop into an indispensable instrument in the process of formulating novel and potentially promising hypotheses

    Modulation of Contact System Proteases by Glycosaminoglycans SELECTIVE ENHANCEMENT OF THE INHIBITION OF FACTOR XIa

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    Abstract We investigated the influence of dextran sulfate, heparin, heparan sulfate, and dermatan sulfate on the inhibition of FXIa (where FXIa is activated factor XI, for example), FXIIa, and kallikrein by C1 inhibitor, α1-antitrypsin, α2-antiplasmin, and antithrombin III. The second-order rate constants for the inhibition of FXIa by C1 inhibitor, α1-antitrypsin, α2-antiplasmin, and antithrombin III, in the absence of glycosaminoglycans, were 1.8, 0.1, 0.43, and 0.32 × 103 M−1 s−1, respectively. The rate constants of the inactivation of FXIa by C1 inhibitor and by antithrombin III increased up to 117-fold in the presence of glycosaminoglycans. These data predicted that considering the plasma concentration of the inhibitors, C1 inhibitor would be the main inhibitor of FXIa in plasma in the presence of glycosaminoglycans. Results of experiments in which the formation of complexes between serine protease inhibitors and FXIa was studied in plasma agreed with this prediction. Glycosaminoglycans did not enhance the inhibition of α-FXIIa, β-FXIIa, or kallikrein by C1 inhibitor. Thus, physiological glycosaminoglycans selectively enhance inhibition of FXIa without affecting the activity of FXIIa and kallikrein, suggesting that glycosaminoglycans may modulate the biological effects of contact activation, by inhibiting intrinsic coagulation without affecting the fibrinolytic potential of FXIIa/kallikrein

    Complement activation during OKT3 treatment: A possible explanation for respiratory side effects

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    Complement activation during OKT3 treatment: A possible explanation for respiratory side effects. Respiratory side effects that sometimes occur during treatment with anti-CD3 MAb OKT3 might result from pulmonary sequestration of activated neutrophils. Therefore, we studied complement activation in relation to activation and pulmonary sequestration of neutrophils during antirejection treatment with OKT3. In each of nine patients studied, plasma C3a-desarg and C4b/c levels increased compared with pretreatment values already in the first sample taken 15 minutes after the first dose of OKT3 (P < 0.05), with peak values at 15 and 30 minutes, respectively. Levels of neutrophil degranulation product elastase (complexed to α1-antitrypsin) also increased already at 15 minutes after the first dose of OKT3 (P < 0.05), which is before elevated levels of the cytokines TNFα, IL-6 or IL-8 were detectable. In contrast, upon subsequent OKT3 administrations or in the control group treated with methylprednisolone, neither complement activation, cytokine release nor neutrophil degranulation occurred. In five studied patients treated with OKT3, pulmonary sequestration of radiolabeled granulocytes was observed from 3 until 15 minutes after the first dose of OKT3, together with peripheral blood granulocytopenia, which lasted at least 30 minutes. In conclusion, we demonstrate a simultaneous activation of complement and pulmonary sequestration of activated granulocytes immediately following the first dose of OKT3. These phenomena may be involved in the development of respiratory side effects complicating this therapy

    Bullying of extremely low birth weight children: Associated risk factors during adolescence

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    Preterm children have many risk factors which may increase their susceptibility to being bullied. AIMS: To examine the prevalence of bullying among extremely low birth weight (ELBW, <1kg) and normal birth weight (NBW) adolescents and the associated sociodemographic, physical, and psychosocial risk factors and correlates among the ELBW children

    PIRCHE-II Is Related to Graft Failure after Kidney Transplantation

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    Individual HLA mismatches may differentially impact graft survival after kidney transplantation. Therefore, there is a need for a reliable tool to define permissible HLA mismatches in kidney transplantation. We previously demonstrated that donor-derived Predicted Indirectly ReCognizable HLA Epitopes presented by recipient HLA class II (PIRCHE-II) play a role in de novo donor-specific HLA antibodies formation after kidney transplantation. In the present Dutch multi-center study, we evaluated the possible association between PIRCHE-II and kidney graft failure in 2,918 donor–recipient couples that were transplanted between 1995 and 2005. For these donors–recipients couples, PIRCHE-II numbers were related to graft survival in univariate and multivariable analyses. Adjusted for confounders, the natural logarithm of PIRCHE-II was associated with a higher risk for graft failure [hazard ratio (HR): 1.13, 95% CI: 1.04–1.23, p = 0.003]. When analyzing a subgroup of patients who had their first transplantation, the HR of graft failure for ln(PIRCHE-II) was higher compared with the overall cohort (HR: 1.22, 95% CI: 1.10–1.34, p &lt; 0.001). PIRCHE-II demonstrated both early and late effects on graft failure in this subgroup. These data suggest that the PIRCHE-II may impact graft survival after kidney transplantation. Inclusion of PIRCHE-II in donor-selection criteria may eventually lead to an improved kidney graft survival

    Eigenvalue asymptotics for weighted Laplace equations on rough Riemannian manifolds with boundary

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    Our topological setting is a smooth compact manifold of dimension two or higher with smooth boundary. Although this underlying topological structure is smooth, the Riemannian metric tensor is only assumed to be bounded and measurable. This is known as a rough Riemannian manifold. For a large class of boundary conditions we demonstrate a Weyl law for the asymptotics of the eigenvalues of the Laplacian associated to a rough metric. Moreover, we obtain eigenvalue asymptotics for weighted Laplace equations associated to a rough metric. Of particular novelty is that the weight function is not assumed to be of fixed sign, and thus the eigenvalues may be both positive and negative. Key ingredients in the proofs were demonstrated by Birman and Solomjak nearly fifty years ago in their seminal work on eigenvalue asymptotics. In addition to determining the eigenvalue asymptotics in the rough Riemannian manifold setting for weighted Laplace equations, we also wish to promote their achievements which may have further applications to modern problems

    A large-scale genome-wide association study meta-analysis of cannabis use disorder

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    Summary Background Variation in liability to cannabis use disorder has a strong genetic component (estimated twin and family heritability about 50–70%) and is associated with negative outcomes, including increased risk of psychopathology. The aim of the study was to conduct a large genome-wide association study (GWAS) to identify novel genetic variants associated with cannabis use disorder. Methods To conduct this GWAS meta-analysis of cannabis use disorder and identify associations with genetic loci, we used samples from the Psychiatric Genomics Consortium Substance Use Disorders working group, iPSYCH, and deCODE (20 916 case samples, 363 116 control samples in total), contrasting cannabis use disorder cases with controls. To examine the genetic overlap between cannabis use disorder and 22 traits of interest (chosen because of previously published phenotypic correlations [eg, psychiatric disorders] or hypothesised associations [eg, chronotype] with cannabis use disorder), we used linkage disequilibrium score regression to calculate genetic correlations. Findings We identified two genome-wide significant loci: a novel chromosome 7 locus (FOXP2, lead single-nucleotide polymorphism [SNP] rs7783012; odds ratio [OR] 1·11, 95% CI 1·07–1·15, p=1·84 × 10−9) and the previously identified chromosome 8 locus (near CHRNA2 and EPHX2, lead SNP rs4732724; OR 0·89, 95% CI 0·86–0·93, p=6·46 × 10−9). Cannabis use disorder and cannabis use were genetically correlated (rg 0·50, p=1·50 × 10−21), but they showed significantly different genetic correlations with 12 of the 22 traits we tested, suggesting at least partially different genetic underpinnings of cannabis use and cannabis use disorder. Cannabis use disorder was positively genetically correlated with other psychopathology, including ADHD, major depression, and schizophrenia. Interpretation These findings support the theory that cannabis use disorder has shared genetic liability with other psychopathology, and there is a distinction between genetic liability to cannabis use and cannabis use disorder. Funding National Institute of Mental Health; National Institute on Alcohol Abuse and Alcoholism; National Institute on Drug Abuse; Center for Genomics and Personalized Medicine and the Centre for Integrative Sequencing; The European Commission, Horizon 2020; National Institute of Child Health and Human Development; Health Research Council of New Zealand; National Institute on Aging; Wellcome Trust Case Control Consortium; UK Research and Innovation Medical Research Council (UKRI MRC); The Brain & Behavior Research Foundation; National Institute on Deafness and Other Communication Disorders; Substance Abuse and Mental Health Services Administration (SAMHSA); National Institute of Biomedical Imaging and Bioengineering; National Health and Medical Research Council (NHMRC) Australia; Tobacco-Related Disease Research Program of the University of California; Families for Borderline Personality Disorder Research (Beth and Rob Elliott) 2018 NARSAD Young Investigator Grant; The National Child Health Research Foundation (Cure Kids); The Canterbury Medical Research Foundation; The New Zealand Lottery Grants Board; The University of Otago; The Carney Centre for Pharmacogenomics; The James Hume Bequest Fund; National Institutes of Health: Genes, Environment and Health Initiative; National Institutes of Health; National Cancer Institute; The William T Grant Foundation; Australian Research Council; The Virginia Tobacco Settlement Foundation; The VISN 1 and VISN 4 Mental Illness Research, Education, and Clinical Centers of the US Department of Veterans Affairs; The 5th Framework Programme (FP-5) GenomEUtwin Project; The Lundbeck Foundation; NIH-funded Shared Instrumentation Grant S10RR025141; Clinical Translational Sciences Award grants; National Institute of Neurological Disorders and Stroke; National Heart, Lung, and Blood Institute; National Institute of General Medical Sciences.Peer reviewe
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