39 research outputs found

    Application of k-means method to pattern recognition in on-line cable partial discharge monitoring

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    On-line Partial Discharge (PD) monitoring is being increasingly adopted in an effort to improve asset management of the vast network of MV and HV power cables. This paper presents a novel method for autonomous recognition of PD patterns recorded under conditions in which a phase-reference voltage waveform from the HV conductors is not available, as is often the case in on-line PD based insulation condition monitoring. The paper begins with an analysis of two significant challenges for automatic PD pattern recognition. A methodology is then proposed for applying the K-Means method to the task of recognizing PD patterns without phase reference information. Results are presented to show that the proposed methodology is capable of recognising patterns of PD activity in on-line monitoring applications for both single-phase and three-phase cables and is also effective technique for rejecting interference signals

    Thromboembolic, bleeding, and mortality risks among patients with nonvalvular atrial fibrillation treated with dual antiplatelet therapy versus oral anticoagulants: A population-based study.

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    BACKGROUND: Dual antiplatelet therapy (DAPT) with aspirin plus clopidogrel is used for stroke prevention in patients with atrial fibrillation (AF) who refuse to take use oral anticoagulants (OACs). However, clinical data comparing these treatments are limited. OBJECTIVE: The purpose of this study was to compare the clinical outcomes between DAPT and OAC in patients with AF. METHODS: A cohort study using a population-wide database of the Hong Kong Hospital Authority was performed. New patients with AF from 2010-2014 who were prescribed DAPT or OAC (warfarin or dabigatran) were followed until July 31, 2016. Outcomes were thromboembolism, bleeding, and death. Propensity score (PS) matching at a ratio of 1:2 was used to select DAPT users with characteristics similar to those of OAC users, analyzed using Poisson regression. RESULTS: Among 51,946 new patients with AF, 8520 users of OAC and DAPT were identified. The likelihood of receiving DAPT over OAC increased with older age and previous intracranial hemorrhage. Among DAPT users, the incidences of thromboembolism, death, and bleeding per 100 patient-years were 15.8, 17.6, and 5.1, respectively. Compared to DAPT users, PS-matched analysis indicated a lower incidence of thromboembolism and/or death among OAC users (dabigatran: incidence rate ratio [IRR] 0.32; 95% confidence interval [CI] 0.19-0.55; warfarin: IRR 0.58; 95% CI 0.36-0.95), with no significant differences in bleeding events. CONCLUSION: DAPT users were at markedly increased risk for thromboembolism and death compared to OAC users. These findings indicate the need for improved stroke risk reduction strategies among patients taking DAPT and the opportunities for using OAC in high-risk groups to prevent additional events

    Genome-Wide Association Study in Asian Populations Identifies Variants in ETS1 and WDFY4 Associated with Systemic Lupus Erythematosus

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    Systemic lupus erythematosus is a complex and potentially fatal autoimmune disease, characterized by autoantibody production and multi-organ damage. By a genome-wide association study (320 patients and 1,500 controls) and subsequent replication altogether involving a total of 3,300 Asian SLE patients from Hong Kong, Mainland China, and Thailand, as well as 4,200 ethnically and geographically matched controls, genetic variants in ETS1 and WDFY4 were found to be associated with SLE (ETS1: rs1128334, P = 2.33×10−11, OR = 1.29; WDFY4: rs7097397, P = 8.15×10−12, OR = 1.30). ETS1 encodes for a transcription factor known to be involved in a wide range of immune functions, including Th17 cell development and terminal differentiation of B lymphocytes. SNP rs1128334 is located in the 3′-UTR of ETS1, and allelic expression analysis from peripheral blood mononuclear cells showed significantly lower expression level from the risk allele. WDFY4 is a conserved protein with unknown function, but is predominantly expressed in primary and secondary immune tissues, and rs7097397 in WDFY4 changes an arginine residue to glutamine (R1816Q) in this protein. Our study also confirmed association of the HLA locus, STAT4, TNFSF4, BLK, BANK1, IRF5, and TNFAIP3 with SLE in Asians. These new genetic findings may help us to gain a better understanding of the disease and the functions of the genes involved

    In-Vivo Expression Profiling of Pseudomonas aeruginosa Infections Reveals Niche-Specific and Strain-Independent Transcriptional Programs

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    Pseudomonas aeruginosa is a threatening, opportunistic pathogen causing disease in immunocompromised individuals. The hallmark of P. aeruginosa virulence is its multi-factorial and combinatorial nature. It renders such bacteria infectious for many organisms and it is often resistant to antibiotics. To gain insights into the physiology of P. aeruginosa during infection, we assessed the transcriptional programs of three different P. aeruginosa strains directly after isolation from burn wounds of humans. We compared the programs to those of the same strains using two infection models: a plant model, which consisted of the infection of the midrib of lettuce leaves, and a murine tumor model, which was obtained by infection of mice with an induced tumor in the abdomen. All control conditions of P. aeruginosa cells growing in suspension and as a biofilm were added to the analysis. We found that these different P. aeruginosa strains express a pool of distinct genetic traits that are activated under particular infection conditions regardless of their genetic variability. The knowledge herein generated will advance our understanding of P. aeruginosa virulence and provide valuable cues for the definition of prospective targets to develop novel intervention strategies

    Frequency of significant fibrosis in various chronic liver diseases: an evaluation with Transient Elastography (TE)

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    INTRODUCTION: Liver biopsy has long been the gold standard to evaluate liver fibrosis. TE was developed as a non- invasive method to assess liver fibrosis by measuring liver stiffness using shear wave velocity. Many studies have proven its’ effectiveness as a method for evaluating liver fibrosis.1-2 The use of TE in UMMC began in 2013. OBJECTIVE: To determine the frequency and aetiology of liver fibrosis and cirrhosis in our local population METHOD: This was a retrospective study conducted at UMMC. Inclusion criteria was all patients who had TE performed from 1 January 2013 to 31 December 2021. Their demographics, clinical characteristics and TE findings were charted. RESULTS: A total of 3066 patients were included, in which 51.7% were males and 48.3% were females. The median CAP value was 271 dB/m. The median E value was 6.5kPa. 11.2% and 11.3% of patients had significant fibrosis (10.1-14.9kPa) and cirrhosis(≥15kPa) respectively. Non-alcoholic fatty liver disease (NAFLD) was noted to be the most common aetiology for fibrosis (32.8%), followed by chronic hepatitis B (CHB) at 25.2%, chronic hepatitis C (CHC) at 6.7% and alcoholic liver disease (ALD) with 1.3%. This finding was also found to be similar in the cirrhosis group (NAFLD 32.5%, CHB 17.2%, CHC 11.9% and ALD 1.4%). 219 DISCUSSION: Our study shows that the most common cause for significant fibrosis and cirrhosis is NAFLD. This is in contrast with previous studies, that reported the most common aetiology being CHB.3-4 This is likely due to the availability of effective treatment for hepatitis B and C. This may also be attributed to the initiation of the national Hepatitis B vaccination program for newborns and the improvement in blood transfusion safety. CONCLUSION: NAFLD has the greatest frequency of fibrosis compared with other aetiologies of liver disease - mainly as there is no effective treatment, unlike viral hepatitis

    Frequency of significant steatosis in various chronic liver diseases: an evaluation with Transient Elastography (TE)

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    INTRODUCTION: TE was developed as a non-invasive method to assess liver fibrosis and steatosis using shear wave velocity. Many studies have proven its’ effectiveness as a method for evaluating liver fibrosis and steatosis.1-2 OBJECTIVE: To determine the prevalence and aetiology of steatosis in our local population. METHOD: This study was conducted as a retrospective review on all patients who had TE performed at UMMC from 1 January 2013 to 31 December 2021. Their demographics, clinical characteristics and TE findings were charted. RESULTS: A total of 3066 patients were included. 51.7% were males and 48.3% were females. The median CAP value was 271 dB/m. The median E value was 6.5kPa. 61.2% of patients had steatosis, with a staggering number of of these patients having significant steatosis (51.8%). 6.3% of patients had S2 steatosis whereas 45.5% of patients had severe (S3) steatosis. Interestingly, in those with S2 steatosis, 34.7% had chronic hepatitis B (CHB), 31.5% had non-alcoholic fatty liver disease (NAFLD), 5.2% with chronic hepatitis C (CHC) and 1% had alcoholic liver disease (ALD). In the S3 steatosis group, 66.7% had NAFLD, followed by ALD (36.6%), CHB (30.1%) and CHC (27.7%). 221 DISCUSSION: It is important to highlight that a large proportion of our patients has significant steatosis. This is likely in keeping with the global rise of obesity and sedentary lifestyle.3 NAFLD is a 4-decades old nomenclature that does not appropriately address the heterogenous pathogenicity of fatty liver disease. Our study reflects this heterogeneity, as it shows that steatosis often co-exists with other diverse aetiologies. CONCLUSION: Whilst NAFLD clearly has the greatest frequency of severe steatosis, it is also present in other aetiologies. These findings support the new terminology of metabolic associated fatty liver disease (MAFLD), which reflects the fact that NAFLD commonly co-exists with other aetiologies

    Neutrinos

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    229 pages229 pages229 pagesThe Proceedings of the 2011 workshop on Fundamental Physics at the Intensity Frontier. Science opportunities at the intensity frontier are identified and described in the areas of heavy quarks, charged leptons, neutrinos, proton decay, new light weakly-coupled particles, and nucleons, nuclei, and atoms

    The New Strategic Environment, November 1971–September 1973

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