339 research outputs found

    Electrical characteristics and modeling of a filamentary dielectric barrier discharge in atmospheric air

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    The electrical characteristics of a filamentary dielectric barrier discharge (DBD) are studied experimentally and numerically. The DBD system which has parallel plate electrodes geometry is powered by a 50 Hz power supply and operated at atmospheric air. A dynamic electric circuit model considering the discharge region and the non-discharge region being connected by a surface resistance is proposed. Simulation using this model is shown to fit the experimentally measured QV diagram satisfactorily. The effects of the air gap distance and the dielectric surface on the discharge behavior are then investigated. It is found that the surface resistivity of the dielectric is one of the important parameters governing the discharge behavior

    Photo-induced reduction of graphene oxide coating on optical waveguide and consequent optical intermodulation

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    Increased absorption of transverse-magnetic (TM) - polarised light by a graphene-oxide (GO) coated polymer waveguide has been observed in the presence of transverse-electric (TE) - polarised light. The GO-coated waveguide exhibits very strong photo-absorption of TE-polarised light - and acts as a TM-pass waveguide polariser. The absorbed TE-polarised light causes a significant temperature increase in the GO film and induces thermal reduction of the GO, resulting in an increase in optical-frequency conductivity and consequently increased optical propagation loss. This behaviour in a GO-coated waveguide gives the action of an inverted optical switch/modulator. By varying the incident TE-polarised light power, a maximum modulation efficiency of 72% was measured, with application of an incident optical power level of 57 mW. The GO-coated waveguide was able to respond clearly to modulated TE-polarised light with a pulse duration of as little as 100 Όs. In addition, no wavelength dependence was observed in the response of either the modulation (TE-polarised light) or the signal (TM-polarised light)

    Background heavy metal concentrations (Cd, Cu, Ni, Pb, Fe and Zn) in modiolus sp. collected from the coast waters of Peninsular Malaysia: A preliminary study.

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    The heavy metal concentrations in little black mussel Modiolus sp. have not been previously reported from Malaysia. In this study, the mussel species is widely distributed the coastal waters of Peninsular Malaysia and this mussel are found in Pantai Sri Tujuh [Kelantan], K. Kedah [Kedah], Kg. Sg. Berembang, Kg. Sg. Baru and Kuala Perlis [Perlis], and Bagan Tiang [Perak], Jeram and Sg. Janggut [Selangor]. From the 12 mussel populations collected in this study, the ranges of the metal concentrations (ÎŒg/g dry weight) in the total soft tissues and shells were 2.246.73 and 4.159.53 for Cd, 10.0231.94 and 6.2810.17 for Cu, 1.3549.38 and 22.2248.45 for Ni, 4.7556.27, and 54.86112.31 for Pb, 5985582 and 158 544 for Fe, and 43.8162 and 1.5025.4 for Zn. To our knowledge, this is the first report on the metal concentrations of Modiolus sp. collected from the coastal waters of Peninsular Malaysia. The present data are important for future ecotoxicological, genetic biochemical and molecular studies in establishing this marine mussel as a good biomonitor

    Editorial: The genetics of human Mendelian skin disorders

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    The skin is comprised of multiple types of cells that serve as a protective barrier. Mutations in the genes that are responsible for protecting the functional integrity of the skin are often found in many inherited skin diseases, more commonly known as the Mendelian human skin disorders. Advances in molecular techniques and sequencing technologies have enabled identification of novel pathogenic variants, which helps to provide insight into genotype–phenotype correlations and to define the genetic basis of these skin disorders. In this Research Topic, a total of ten articles are published, including those describing findings from case studies and original research, as well as a mini review of current genetic diagnosis strategies, novel gene variants, and genotype-phenotype correlations in human Mendelian skin disorders

    A Novel HNF4A Mutation Causing Three Phenotypic Forms of Glucose Dysregulation in a Family

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    Maturity-onset diabetes of the young (MODY) classically describes dominantly inherited forms of monogenic diabetes diagnosed before 25 years of age due to pancreatic ÎČ-cell dysfunction. In contrast, mutations in certain MODY genes can also present with transient or persistent hyperinsulinemic hypoglycemia in newborn infants, reflecting instead ÎČ-cell dysregulation. Of the MODY genes described to date, only hepatocyte nuclear factor-4-alpha (HNF4A; MODY1) and hepatocyte nuclear factor-1-alpha (HNF1A; MODY3) mutations may result in a biphasic phenotype of hypoglycemia in early life and hyperglycemia in later life. We report a family with a novel HNF4A mutation with diverse phenotypic presentations of glucose dysregulation. The proband was a term, appropriate-for-gestational age male infant with symptomatic hypoglycemia on day 3 of life needing high glucose infusion rate to maintain normoglycemia. He was born to a non-obese and non-diabetic mother. Glucose regulation was optimized using diazoxide upon confirmation of hyperinsulinism. Cascade genetic screening identified the same mutation in his father and elder sister, but mother was negative. Father was diagnosed with Type 1 diabetes at 15 years of age that required insulin therapy. Proband's elder sister, born at term appropriate for gestational age, presented with transient neonatal hypoglycemia needing parenteral glucose infusion for a week followed by spontaneous resolution. The paternal grandparents were negative for this mutation, confirming a paternal de novo mutation and autosomal dominant inheritance in this family. This pedigree suggests that the presence of early-onset paternal diabetes should prompt molecular testing in infants presenting in the newborn period with diazoxide-responsive hyperinsulinemic hypoglycemia, even in the absence of maternal diabetes and macrosomia.This article is freely available via Open Access. Click on the Publisher URL to access it via the publisher's site.published version, accepted version, submitted versio

    A pro-inflammatory diet in people with multiple sclerosis is associated with an increased rate of relapse and increased FLAIR lesion volume on MRI in early multiple sclerosis: A prospective cohort study

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    First published online May 6, 2023Background: A pro-inflammatory diet has been posited to induce chronic inflammation within the central nervous system (CNS), and multiple sclerosis (MS) is an inflammatory disease of the CNS. Objective: We examined whether Dietary Inflammatory Index (DIIÂź)) scores are associated with measures of MS progression and inflammatory activity. Methods: A cohort with a first clinical diagnosis of CNS demyelination was followed annually (10 years, n=223). At baseline, 5- and 10-year reviews, DII and energy-adjusted DII (E-DIITM) scores were calculated (food frequency questionnaire) and assessed as predictors of relapses, annualised change in disability (Expanded Disability Status Scale) and two magnetic resonance imaging measures; fluid-attenuated inversion recovery (FLAIR) lesion volume and black hole lesion volume. Results: A more pro-inflammatory diet was associated with a higher relapse risk (highest vs. lowest E-DII quartile: hazard ratio=2.24, 95% confidence interval (CI)= −1.16, 4.33, p=0.02). When we limited analyses to those assessed on the same manufacturer of scanner and those with a first demyelinating event at study entry (to reduce error and disease heterogeneity), an association between E-DII score and FLAIR lesion volume was evident (ÎČ=0.38, 95% CI=0.04, 0.72, p=0.03). Conclusion: There is a longitudinal association between a higher DII and a worsening in relapse rate and periventricular FLAIR lesion volume in people with MS.Alice M Saul, Bruce V Taylor, Leigh Blizzard, Steve Simpson-Yap, Wendy H Oddy, Nittin Shivappa, James R HĂ©bert, Lucinda J Black, Anne-Louise Ponsonby, Simon A Broadley, Jeanette Lechner-Scott and Ingrid van der Mei, Ausimmune, AusLong Investigators Grou

    A joint fermi-gbm and ligo/virgo analysis of compact binary mergers from the first and second gravitational-wave observing runs

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    We present results from offline searches of Fermi Gamma-ray Burst Monitor (GBM) data for gamma-ray transients coincident with the compact binary coalescences observed by the gravitational-wave (GW) detectors Advanced LIGO and Advanced Virgo during their first and second observing runs. In particular, we perform follow-up for both confirmed events and low significance candidates reported in the LIGO/Virgo catalog GWTC-1. We search for temporal coincidences between these GW signals and GBM-triggered gamma-ray bursts (GRBs). We also use the GBM Untargeted and Targeted subthreshold searches to find coincident gamma-rays below the onboard triggering threshold. This work implements a refined statistical approach by incorporating GW astrophysical source probabilities and GBM visibilities of LIGO/Virgo sky localizations to search for cumulative signatures of coincident subthreshold gamma-rays. All search methods recover the short gamma-ray burst GRB 170817A occurring ~1.7 s after the binary neutron-star merger GW170817. We also present results from a new search seeking GBM counterparts to LIGO single-interferometer triggers. This search finds a candidate joint event, but given the nature of the GBM signal and localization, as well as the high joint false alarm rate of 1.1 x 10−6 Hz, we do not consider it an astrophysical association. We find no additional coincidences

    Search for strong gravity in multijet final states produced in pp collisions at √s=13 TeV using the ATLAS detector at the LHC

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    A search is conducted for new physics in multijet final states using 3.6 inverse femtobarns of data from proton-proton collisions at √s = 13TeV taken at the CERN Large Hadron Collider with the ATLAS detector. Events are selected containing at least three jets with scalar sum of jet transverse momenta (HT) greater than 1TeV. No excess is seen at large HT and limits are presented on new physics: models which produce final states containing at least three jets and having cross sections larger than 1.6 fb with HT > 5.8 TeV are excluded. Limits are also given in terms of new physics models of strong gravity that hypothesize additional space-time dimensions

    Measurement of the View the tt production cross-section using eÎŒ events with b-tagged jets in pp collisions at √s = 13 TeV with the ATLAS detector

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    This paper describes a measurement of the inclusive top quark pair production cross-section (σttÂŻ) with a data sample of 3.2 fb−1 of proton–proton collisions at a centre-of-mass energy of √s = 13 TeV, collected in 2015 by the ATLAS detector at the LHC. This measurement uses events with an opposite-charge electron–muon pair in the final state. Jets containing b-quarks are tagged using an algorithm based on track impact parameters and reconstructed secondary vertices. The numbers of events with exactly one and exactly two b-tagged jets are counted and used to determine simultaneously σttÂŻ and the efficiency to reconstruct and b-tag a jet from a top quark decay, thereby minimising the associated systematic uncertainties. The cross-section is measured to be: σttÂŻ = 818 ± 8 (stat) ± 27 (syst) ± 19 (lumi) ± 12 (beam) pb, where the four uncertainties arise from data statistics, experimental and theoretical systematic effects, the integrated luminosity and the LHC beam energy, giving a total relative uncertainty of 4.4%. The result is consistent with theoretical QCD calculations at next-to-next-to-leading order. A fiducial measurement corresponding to the experimental acceptance of the leptons is also presented
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