526 research outputs found

    Non-physiological increase of AV conduction time in sinus disease patients programmed in AAIR-based pacing mode

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    Purpose The EVOCAVDS trial aimed to quantify the paradoxal atrioventricular (AV) conduction time lengthening in sinus node (SD) patients (pts) paced in AAIR-based pacing mode. Methods SD pts, implanted with dual-chamber pacemaker programmed in AAIR-based pacing mode, were randomized in two arms for a 1-month period: the low atrial pacing (LAP; basic rate at 60 bpm, dual sensor with minimal slope) and the high atrial pacing (HAP; basic rate at 70 bpm, dual sensor with optimized slope, overdrive pacing) arm. At 1 month, crossover was performed for an additional 1-month period. AV conduction time, AV block occurrence and AV conduction time adaptation during exercise were ascertained from device memories at each follow-up. Results Seventy-nine pts participated to the analysis (75 ± 8 years; 32 male; PR = 184 ± 38 ms; bundle branch block n = 12; AF history n = 36; antiarrhythmic treatment n = 53; beta-blockers n = 27; class III/Ic n = 18; both n = 8). The mean AV conduction time was significantly greater during the HAP (275 ± 51 ms) vs. LAP (263 ± 49 ms) period (p < 0.0001). Class III/Ic drugs were the only predictors of this abnormal behaviour. Degree II/III AV blocks occurred in 49 % of pts in the HAP vs. 19 % in the LAP period (p < 0.0001). Fifty-two patients (66 %) presented a lengthening of AV conduction time during exercise. Conclusion AAIR-based pacing in SD pts may induce a significant lengthening of pts’ AV conduction time, including frequent abnormal adaptation of AV conduction time during exercise

    Tunable hybrid surface waves supported by a graphene layer

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    We study surface waves localized near a surface of a semi-infinite dielectric medium covered by a layer of graphene in the presence of a strong external magnetic field. We demonstrate that both TE-TM hybrid surface plasmons can propagate along the graphene surface. We analyze the effect of the Hall conductivity on the disper- sion of hybrid surface waves and suggest a possibility to tune the plasmon dispersion by the magnetic field.Comment: 3 pages, 3 figure

    Screening, diagnosis and monitoring of sarcopenia:When to use which tool?

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    Background & aims: Sarcopenia is a muscle disorder associated with loss of muscle mass, strength and function. Early screening, diagnosis and treatment may improve outcome in different disease conditions. A wide variety of tools for estimation of muscle mass is available and each tool has specific technical requirements. However, different investigational settings and lack of homogeneity of populations influence the definition of gold standards, proving it difficult to systematically adopt these tools. Recently, the European Working Group on Sarcopenia in Older People (EWGSOP) published a revised recommendation (EWGSOP-2) and algorithm for using tools for screening and diagnosing sarcopenia. However, agreement of the EWGSOP2 criteria with other classifications is poor and although an overview of available tools is valuable, for the purpose of clinical decision-making the reverse is useful; a given scenario asks for the most suitable tools. Results: Tools were identified for screening, diagnostics and longitudinal monitoring of muscle mass. For each of these clinical scenarios the most appropriate tools were listed and for each technique their usability is specified based on sensitivity and specificity. Based on this information a specific recommendation is made for each clinical scenario. Conclusion: This narrative review provides an overview of currently available tools and future developments for different clinical scenarios such as screening, diagnosis and longitudinal monitoring of alterations in muscle status. It supports clinical decision-making in choosing the right tools for muscle mass quantification depending on the need within a given clinical scenario as well as the local availability and expertise. (C) 2022 The Author(s). Published by Elsevier Ltd on behalf of European Society for Clinical Nutrition and Metabolism

    Towards a Sustainable Governance of Information Systems: Devising a Maturity Assessment Tool of Eco-Responsibility Inspired by the Balanced Scorecard

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    Part 3: Section 2: Sustainable and Responsible InnovationInternational audienceThe assessment of the maturity of Information System (IS) regarding its contribution to corporate social responsibility policy is considered as a stake for organizations. However, few research efforts have been dedicated to this evaluation and even less to the elaboration of a management tool. This paper adopts an engineering perspective to develop a performance assessment approach in this field. Theoretically, this communication (1) mobilizes the methodology of engineering research to build a measurement system of the IS maturity in relation to the economic, social and environmental performance, (2) extends the researches about the sustainable balanced scorecard (SBSC) to the field of IS governance. Practically, this study provides organizations with a global approach to this complex phenomenon as well as a guide to assess it. The originality of this research lies in the application of the conceptual framework of the SBSC to a new research domain

    Velocity field measurements of cavitating flows

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    A particle Image Velocimetry (PIV) system has been developed to study the microfluid mechanics of cavitating flows. Planar PIV was used to examine the non-cavitating flow in the thin boundary layer near a hydrofoil surface for the cases of a naturally developing boundary layer and a boundary layer stimulated to turbulence by roughness near the foil leading edge. PIV was also used to examine the flow near the surface of individual cavitation bubbles and incipient attached cavitation. A system was devised to create a single nucleus in the flow upstream of a hydrofoil, and planar PIV was used to study the flow around the resulting traveling cavitation bubble. Velocity vectors were determined close to the solid surfaces and the gas/liquid interfaces of the bubbles. Seeding of the flow with particles did not result in the addition of active cavitation nuclei.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47070/1/348_2004_Article_BF00189302.pd

    Graphene plasmonics

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    Two rich and vibrant fields of investigation, graphene physics and plasmonics, strongly overlap. Not only does graphene possess intrinsic plasmons that are tunable and adjustable, but a combination of graphene with noble-metal nanostructures promises a variety of exciting applications for conventional plasmonics. The versatility of graphene means that graphene-based plasmonics may enable the manufacture of novel optical devices working in different frequency ranges, from terahertz to the visible, with extremely high speed, low driving voltage, low power consumption and compact sizes. Here we review the field emerging at the intersection of graphene physics and plasmonics.Comment: Review article; 12 pages, 6 figures, 99 references (final version available only at publisher's web site

    Past Achievements and Future Challenges in 3D Photonic Metamaterials

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    Photonic metamaterials are man-made structures composed of tailored micro- or nanostructured metallo-dielectric sub-wavelength building blocks that are densely packed into an effective material. This deceptively simple, yet powerful, truly revolutionary concept allows for achieving novel, unusual, and sometimes even unheard-of optical properties, such as magnetism at optical frequencies, negative refractive indices, large positive refractive indices, zero reflection via impedance matching, perfect absorption, giant circular dichroism, or enhanced nonlinear optical properties. Possible applications of metamaterials comprise ultrahigh-resolution imaging systems, compact polarization optics, and cloaking devices. This review describes the experimental progress recently made fabricating three-dimensional metamaterial structures and discusses some remaining future challenges

    A multi-stage genome-wide association study of bladder cancer identifies multiple susceptibility loci.

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    We conducted a multi-stage, genome-wide association study of bladder cancer with a primary scan of 591,637 SNPs in 3,532 affected individuals (cases) and 5,120 controls of European descent from five studies followed by a replication strategy, which included 8,382 cases and 48,275 controls from 16 studies. In a combined analysis, we identified three new regions associated with bladder cancer on chromosomes 22q13.1, 19q12 and 2q37.1: rs1014971, (P = 8 × 10⁻¹²) maps to a non-genic region of chromosome 22q13.1, rs8102137 (P = 2 × 10⁻¹¹) on 19q12 maps to CCNE1 and rs11892031 (P = 1 × 10⁻⁷) maps to the UGT1A cluster on 2q37.1. We confirmed four previously identified genome-wide associations on chromosomes 3q28, 4p16.3, 8q24.21 and 8q24.3, validated previous candidate associations for the GSTM1 deletion (P = 4 × 10⁻¹¹) and a tag SNP for NAT2 acetylation status (P = 4 × 10⁻¹¹), and found interactions with smoking in both regions. Our findings on common variants associated with bladder cancer risk should provide new insights into the mechanisms of carcinogenesis
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