Publications

Stress-strain curves for wire arc additively manufactured steels

Interest in the use of wire arc additive manufacturing (WAAM) in construction has increased rapidly in recent years. Key to facilitating wider application is an improved understanding of the material behaviour. In particular, with structural design by finite element analysis in mind, constitutive models to describe the full range stress-strain response of WAAM steels are needed; development of such models is the focus of the present study. WAAM normal-strength steels generally exhibit a stress-strain response featuring a well-defined yield point, a yield plateau (for machined material) or slightly inclined yield plateau (for as-built material) and subsequent strain hardening, while the stress-strain response of WAAM high-strength steels is typically rounded, with no distinct yield point or plateau. This behaviour is similar to that of conventionally-produced steels, and hence can be represented analytically using existing material models, but with suitable modifications — a quad-linear or bilinear plus nonlinear hardening model and a two-stage Ramberg-Osgood model are proposed for WAAM normal- and high-strength steels, respectively. Predictive expressions or standardised values for the input parameters required in the models are developed and calibrated against a comprehensive database of WAAM steel coupon test results collected from the literature. The experimental database comprises over 600 engineering stress-strain curves and covers different feedstock wires, surface finishes (i.e. machined and as-built), material thicknesses, directions of testing and printing strategies. The proposed material models are shown to accurately predict the full stress-strain curves of WAAM steels, and are considered to be suitable for incorporation into analytical, numerical and design models for WAAM steel structures.

Suppression of GATA-3 Nuclear Import and Phosphorylation: A Novel Mechanism of Corticosteroid Action in Allergic Disease

Peter Barnes and colleagues show that corticosteroids have a potent inhibitory effect on GATA-3 via two interacting mechanisms that suppress Th2 cytokine expression. This novel mechanism of corticosteroid action may help explain the efficacy of corticosteroids in allergic diseases.

Rhinovirus Infection Induces Degradation of Antimicrobial Peptides and Secondary Bacterial Infection in Chronic Obstructive Pulmonary Disease

Rationale: Chronic obstructive pulmonary disease (COPD) exacerbations are associated with virus (mostly rhinovirus) and bacterial infections, but it is not known whether rhinovirus infections precipitate secondary bacterial infections.Objectives: To investigate relationships between rhinovirus infection and bacterial infection and the role of antimicrobial peptides in COPD exacerbations.Methods: We infected subjects with moderate COPD and smokers and nonsmokers with normal lung function with rhinovirus. Induced sputum was collected before and repeatedly after rhinovirus infection and virus and bacterial loads measured with quantitative polymerase chain reaction and culture. The antimicrobial peptides secretory leukoprotease inhibitor (SLPI), elafin, pentraxin, LL-37, α-defensins and β-defensin-2, and the protease neutrophil elastase were measured in sputum supernatants.Measurements and Main Results: After rhinovirus infection, secondary bacterial infection was detected in 60% of subjects with COPD, 9.5% of smokers, and 10% of nonsmokers (P < 0.001). Sputum virus load peaked on Days 5–9 and bacterial load on Day 15. Sputum neutrophil elastase was significantly increased and SLPI and elafin significantly reduced after rhinovirus infection exclusively in subjects with COPD with secondary bacterial infections, and SLPI and elafin levels correlated inversely with bacterial load.Conclusions: Rhinovirus infections are frequently followed by secondary bacterial infections in COPD and cleavage of the antimicrobial peptides SLPI and elafin by virus-induced neutrophil elastase may precipitate these secondary bacterial infections. Therapy targeting neutrophil elastase or enhancing innate immunity may be useful novel therapies for prevention of secondary bacterial infections in virus-induced COPD exacerbations.

High concentrations of B-adrenergic agonists inhibit DNA binding of glucocorticoids in human lung <i>in vitro</i>

Conference Article| May 01 1995 High concentrations of B-adrenergic agonists inhibit DNA binding of glucocorticoids in human lung in vitro I.M. ADCOCK; I.M. ADCOCK 1Department of Thoracic Medicine, National Heart & Lung Institute, London, SW3 6LY. U.K. Search for other works by this author on: This Site PubMed Google Scholar M.J. PETERS; M.J. PETERS 1Department of Thoracic Medicine, National Heart & Lung Institute, London, SW3 6LY. U.K. Search for other works by this author on: This Site PubMed Google Scholar C.R. BROWN; C.R. BROWN 1Department of Thoracic Medicine, National Heart & Lung Institute, London, SW3 6LY. U.K. Search for other works by this author on: This Site PubMed Google Scholar D.A. STEVENS; D.A. STEVENS 1Department of Thoracic Medicine, National Heart & Lung Institute, London, SW3 6LY. U.K. Search for other works by this author on: This Site PubMed Google Scholar P.J. BARNES P.J. BARNES 1Department of Thoracic Medicine, National Heart & Lung Institute, London, SW3 6LY. U.K. Search for other works by this author on: This Site PubMed Google Scholar Biochem Soc Trans (1995) 23 (2): 217S. https://doi.org/10.1042/bst023217s Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Cite Icon Cite Get Permissions Citation I.M. ADCOCK, M.J. PETERS, C.R. BROWN, D.A. STEVENS, P.J. BARNES; High concentrations of B-adrenergic agonists inhibit DNA binding of glucocorticoids in human lung in vitro. Biochem Soc Trans 1 May 1995; 23 (2): 217S. doi: https://doi.org/10.1042/bst023217s Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsBiochemical Society Transactions Search Advanced Search This content is only available as a PDF. © 1995 Biochemical Society1995 Article PDF first page preview Close Modal You do not currently have access to this content.

Innovative shear connectors for composite cold-formed steel-timber structures: An experimental investigation

An experimental investigation into the behaviour of bespoke shear connectors designed to generate composite action in cold-formed steel-timber structures is presented. The response of the shear connectors was assessed through a comprehensive set of push-out tests, where the cold-formed steel thickness and the connector type and material were varied. Previous studies have shown that while the use of ordinary self-drilling screws as shear connectors enables the development of some composite action, their performance was inhibited by timber embedment. Hence, the main feature of the innovative shear connectors was the introduction of a fitting around the screw to mobilise higher timber embedment forces. The best performing shear connectors achieved about double the shear resistance, four times the initial slip modulus ks and seven times the mid-range slip modulus ks,m of ordinary self-drilling screws. An analytical model presented in previous research was extended to describe the response of the innovative shear connectors developed in this study. The model was validated against the push-out test results, and shown to be able to accurately predict the ultimate load, slip at ultimate load, and the two slip moduli ks and ks,m of the innovative connectors, with mean model-to-test ratios of 1.01, 1.15, 1.29 and 1.19 respectively.

Contrast echocardiology

No abstract is provided for this article.

DEM analysis of the influence of the intermediate stress ratio on the critical-state behaviour of granular materials

Imaging of the Left Ventricle by Contrast Echocardiography

No abstract is provided for this article.

Subject Index

P2631Accuracy of optical coherence tomography in predicting functional significance of coronary stenosis determined by fractional flow reserve: a meta-analysis

No abstract is provided for this article.

THE GALACTIC CENSUS OF HIGH- AND MEDIUM-MASS PROTOSTARS. I. CATALOGS AND FIRST RESULTS FROM MOPRA HCO ⁺ MAPS

The Census of High- and Medium-mass Protostars (CHaMP) is the first large-scale, unbiased, uniform mapping survey at sub-parsec scale resolution of 90 GHz line emission from massive molecular clumps in the Milky Way. We present the first Mopra (ATNF) maps of the CHaMP survey region (300{\deg}>l>280{\deg}) in the HCO+ J=1-0 line, which is usually thought to trace gas at densities up to 10^11 m-3. In this paper we introduce the survey and its strategy, describe the observational and data reduction procedures, and give a complete catalogue of moment maps of the HCO+ J=1-0 emission from the ensemble of 301 massive molecular clumps. From these maps we also derive the physical parameters of the clumps, using standard molecular spectral-line analysis techniques. This analysis yields the following range of properties: integrated line intensity 1-30 K km s-1, peak line brightness 1-7 K, linewidth 1-10 km s-1, integrated line luminosity 0.5-200 K km s-1 pc^2, FWHM size 0.2-2.5 pc, mean projected axial ratio 2, optical depth 0.08-2, total surface density 30-3000 M{\sun} pc-2, number density 0.2-30 x 10^9 m-3, mass 15-8000 M{\sun}, virial parameter 1-55, and total gas pressure 0.3-700 pPa. We find that the CHaMP clumps do not obey a Larson-type size-linewidth relation. Among the clumps, there exists a large population of subthermally excited, weakly-emitting (but easily detectable) dense molecular clumps, confirming the prediction of Narayanan et al. (2008). These weakly-emitting clumps comprise 95% of all massive clumps by number, and 87% of the molecular mass, in this portion of the Galaxy; their properties are distinct from the brighter massive star-forming regions that are more typically studied. If the clumps evolve by slow contraction, the 95% of fainter clumps may represent a long-lived stage of pressure-confined, gravitationally stable massive clump evolution, while the CHaMP ... (abridged)

Ovalbumin aerosol challenge in actively sensitized guinea pigs: relationship between airway microvascular leakage and airflow obstruction

Airway inflammation is a common feature of asthma, and one of the cardinal features of inflammation is increased microvascular permeability. We investigated the characteristics of inhaled ovalbumin challenge‐induced airflow obstruction and airway microvascular leakage in vivo in mechanically ventilated guinea pigs actively sensitized to ovalbumin. A method was used to quantify both airflow obstruction and airway microvascular leakage in order to investigate the relationship between these 2 pathophysiological features in the same animal. Airway microvascular leakage was assessed by Evans blue dye extravasation into airway tissues. Actively sensitized guinea pigs developed both acute airflow obstruction (increased lung resistance and reduced dynamic lung compliance) and Evans blue dye extravasation in response to exposure to aerosolised ovalbumin. Evans blue dye extravasation was preferentially distributed in the distal airways and correlated with airflow obstruction. The results show that inhaled allergen induced both acute airflow obstruction and airway microvascular leakage.

Senescence and Fibrotic Markers Are Induced by Oxidative Stress in Small Airway Fibroblasts from COPD Patients

Byzantine-Resilient Locally Optimum Detection Using Collaborative Autonomous Networks

In this paper, we propose a locally optimum detection (LOD) scheme for detecting a weak radioactive source buried in background clutter. We develop a decentralized algorithm, based on alternating direction method of multipliers (ADMM), for implementing the proposed scheme in autonomous sensor networks. Results show that algorithm performance approaches the centralized clairvoyant detection algorithm in the low SNR regime, and exhibits excellent convergence rate and scaling behavior (w.r.t. number of nodes). We also devise a low-overhead, robust ADMM algorithm for Byzantine-resilient detection, and demonstrate its robustness to data falsification attacks.

Tuberculosis of the thyroid: Two case reports

Drug-Eluting Stents

Coronary stents have revolutionized the management of patients with obstructive coronary artery disease. This chapter will review the problems associated with percutaneous coronary intervention when performed using balloon angioplasty and bare-metal stents, before discussing the first and second generation drug-eluting stents (DESs). Finally, the new generation of DESs, which are currently undergoing evaluation in clinical trials, will be reviewed.

Characterization and distribution of P2-purinoceptor subtypes in rat pulmonary vessels.

To characterize P2-purinoceptors in pulmonary vessels we have examined the effects of ATP analogs on rat isolated pulmonary artery and vein in vitro. The rank order of potency for causing vasoconstriction was: alpha,beta-methylene-ATP (alpha,beta-meATP) greater than beta,gamma-methylene-ATP (beta,gamma-meATP) greater than 2-methylthio-ATP (2m.S.ATP) greater than ATP for arteries; and alpha,beta-meATP much greater than beta,gamma-meATP = 2m.S.ATP greater than ATP for veins, indicating that a P2x receptor was involved. The contractile response to these analogs was virtually abolished after desensitization of P2x-receptors by alpha,beta-meATP. Removal of the endothelial cells enhanced the contractile responses to all of the ATP analogs in both arteries and veins. The rank order of potency for vasodilatation was 2m.S.ATP much greater than ATP = beta,gamma-meATP much greater than alpha,beta-meATP for arteries and 2m.S.ATP much greater than ATP = beta-gamma-meATP, with alpha,beta-meATP being no effect for veins, indicating a P2y receptor. Pretreatment of the pulmonary arteries with the P2y-antagonist reactive blue 2 caused a rightward shift of the dose-response curves to 2m.S.ATP, ATP and beta,gamma-meATP. Reactive blue 2 was only used with the pulmonary arteries. Removal of the endothelium converted the relaxant responses to all the ATP analogs (except to ATP in pulmonary artery) to further contraction. In the pulmonary artery, the small endothelium-independent relaxation induced by ATP was abolished completely by pretreating the vessels with 100 microM theophylline (a P1-purinoceptor antagonist), suggesting that it was due to conversion of ATP to adenosine.(ABSTRACT TRUNCATED AT 250 WORDS)

One-Year Outcomes after Myval Implantation in Patients with Bicuspid Aortic Valve Stenosis—A Multicentre Real-World Experience

Background: Bicuspid aortic valve (BAV) affects approximately 1.5% of the general population and is seen in nearly 50% of candidates for aortic valve replacement (AVR). Despite increasingly utilised transcatheter aortic valve implantation (TAVI) in aortic stenosis (AS) patients, its use among patients with severe bicuspid AS is limited as BAV is a heterogeneous disease associated with multiple and complex anatomical challenges. Aim: To investigate the one-year outcomes of TAVI using the balloon-expandable Myval transcatheter heart valve (THV) (Meril Life Sciences Pvt. Ltd., Vapi, India) in patients with severe bicuspid AS. Methods and results: We collected data from consecutive patients with bicuspid AS who underwent TAVI with the Myval THV and had at least one-year follow-up. Baseline characteristics, procedural, and 30-day echocardiographic and clinical outcomes were collected. Sixty-two patients were included in the study. The median age was 72 [66.3, 77.0] years, 45 (72.6%) were males, and the mean STS PROM score was 3.2 ± 2.2%. All TAVI procedures were performed via the transfemoral route. The median follow-up duration was 13.5 [12.2, 18.3] months; all-cause mortality was reported in 7 (11.3%) patients and cardiovascular hospitalisation in 6 (10.6%) patients. All-stroke was reported in 2 (3.2%), permanent pacemaker implantation 5 (8.3%), and myocardial infarction 1 (1.6%) patients. The echocardiographic assessment revealed a mean pressure gradient of 10 [8, 16.5] mmHg, effective orifice area 1.7 [1.4, 1.9] cm2, moderate AR in 1 (2%), mild AR in 14 (27%), and none/trace AR in 37 (71%). In total, 1 patient was diagnosed with valve thrombosis (2.1%), Stage II (moderate) haemodynamic deterioration was seen in 3 (6.4%), and stage III (severe) haemodynamic deterioration in 1 (2.1%) patient. Conclusions: TAVI with the Myval THV in selected BAV anatomy is associated with favourable one-year hemodynamic and clinical outcomes.