A Novel Generalized Scattering Through Heterostructure With A Time-Periodic Potential

Interaction with external time-dependent fields in low-dimensional systems leads in many cases to completely new phenomena of electronic transport. Dealing with a driven system, its quantum dynamics is adequately analyzed in terms of the Floquet or quasienergy spectrum. In this paper, we extend the effective mass model to the case of different effective masses for different materials in a heterostructure. For this case we present a general method which allows us to treat a time modulated potential acting upon a quantum well structure. We extend the work of Wenjun Li and LE Reichl,[1], and consider the case of a multilayer composed of different materials, assuming th

Magnetostatic surface waves propagation at the interface between ferrite and MTMs parallel plate waveguide structure

Accepted 10/6/2013 Abstract: This work considers magnetostatic surface waves propagation in parallel structure composed of ferrite film bounded from below by metamaterial (MTM) placed on metal substrate and from top by air. The Maxwell equations are used to analyse propagation of slow (magnetostatic) surface electromagnetic wave in this structure. Results show that magnetostatic surface wave (MSSW) propagates at certain range of frequencies and varies as both MTM layer and ferrite layer thicknesses change. The new behaviour of the proposed waveguide in the presence of MTM in particular the appearance of the unidirectional MSSW is promising for practical applications such as isolators

The Sensitivity of TE Filed Propagating in LHM-Antiferromagnetic Sensor

A three-layer waveguide structure sensor consists of LHMs (left-handed materials) film surrounded by dielectric cladding and antiferromagnetic substrate is proposed. LHMs known as MTMs (metamaterials) have simultaneous negative permeability and permittivity. The dispersion relation for the structure is derived for TE guided modes. Two ranges of frequencies are chosen such that Voigt permeability, μv, either negative or positive. The sensitivity is proven to be affected by different parameters including the film thickness, LHM parameters, and Voigt frequency

Propagation of Electromagnetic Surface Waves through a Ferrite Slab Bounded by Metamaterials

Recently there has been growing interest in a new type of electromagnetic materials called lefthanded materials (LHMs), or metamaterials. Over thirty years ago Veselago [1] predicted that electromagnetic wave propagation in a medium having simultaneously negative permittivity ε and permeability μ should give rise to several peculiar characteristics. Veselago predicted that in LHM the energy flow (Pointing vector) is anti-parallel to the phase velocity (or wave vector) while in regular materials termed right-handed materials (RHMs), having simultaneously positive ε and μ the Pointing vector (energy flow) gives the direction of the phase velocity. In this communication, the dispersion relationship describing the propagation of electromagnetic surface modes supported by a finite thickness ferrite slab bounded by LHMs media is investigated and discussed

Survival and quality of life in incident systemic sclerosis-related pulmonary arterial hypertension

Background: Pulmonary arterial hypertension (PAH) is a leading cause of mortality in systemic sclerosis (SSc). We sought to determine survival, predictors of mortality, and health-related quality of life (HRQoL) related to PAH in a large SSc cohort with PAH. Methods: We studied consecutive SSc patients with newly diagnosed (incident) World Health Organization (WHO) Group 1 PAH enrolled in a prospective cohort between 2009 and 2015. Survival methods were used to determine age and sex-adjusted standardised mortality ratio (SMR) and years of life lost (YLL), and to identify predictors of mortality. HRQoL was measured using the Short form 36 (SF-36) instrument. Results: Among 132 SSc-PAH patients (112 female (85%); mean age 62 ± 11 years), 60 (45.5%) died, with a median (±IQR) survival time from PAH diagnosis of 4.0 (2.2-6.2) years. Median (±IQR) follow up from study enrolment was 3.8 (1.6-5.8) years. The SMR for patients with SSc-PAH was 5.8 (95% CI 4.3-7.8), with YLL of 15.2 years (95% CI 12.3-18.1). Combination PAH therapy had a survival advantage (p < 0.001) compared with monotherapy, as did anticoagulation compared with no anticoagulation (p < 0.003). Furthermore, combination PAH therapy together with anticoagulation had a survival benefit compared with monotherapy with or without anticoagulation and combination therapy without anticoagulation (hazard ratio 0.28, 95% CI 0.1-0.7). Older age at PAH diagnosis (p = 0.03), mild co-existent interstitial lung disease (ILD) (p = 0.01), worse WHO functional class (p = 0.03) and higher mean pulmonary arterial pressure at PAH diagnosis (p = 0.001), and digital ulcers (p = 0.01) were independent predictors of mortality. Conclusions: Despite the significant benefits conferred by advanced PAH therapies suggested in this study, the median survival in SSc PAH remains short at only 4 years.Kathleen Morrisroe, Wendy Stevens, Molla Huq, David Prior, Jo Sahhar, Gene-Siew Ngian, David Celermajer, Jane Zochling, Susanna Proudman, Mandana NikpourEmail author and the Australian Scleroderma Interest Group (ASIG

The association of low complement with disease activity in systemic sclerosis: a prospective cohort study

Background: In some rheumatic diseases such as systemic lupus erythematosus (SLE), low serum complement ('hypocomplementaemia') is a feature of active disease. However, the role of hypocomplementaemia in systemic sclerosis (SSc) is unknown. We sought to determine the frequency, clinical associations and relationship to disease activity of hypocomplementaemia in SSc. Methods: The study included 1140 patients fulfilling the 2013 American College of Rheumatology criteria for SSc. Demographic, serological and clinical data, obtained prospectively through annual review, were analysed using univariable methods. Linear and logistic regression, together with generalised estimating equations, were used to determine the independent correlates of hypocomplementaemia ever, and at each visit, respectively. Results: At least one episode of hypocomplementaemia (low C3 and/or low C4) occurred in 24.1 % of patients over 1893 visits; these patients were more likely to be seropositive for anti-ribonucleoprotein (OR = 3.8, p = 0.002), anti-Ro (OR = 2.2, p = 0.002), anti-Smith (OR = 6.3, p = 0.035) and anti-phospholipid antibodies (OR = 1.4, p = 0.021) and were more likely to display features of overlap connective tissue disease, in particular polymyositis (OR = 16.0, p = 0.012). However, no association was found between hypocomplementaemia and either the European Scleroderma Study Group disease activity score or any of its component variables (including erythrocyte sedimentation rate) in univariate analysis. Among patients with SSc overlap disease features, those who were hypocomplementaemic were more likely to have digital ulcers (OR = 1.6, p = 0.034), tendon friction rubs (OR = 2.4, p = 0.037), forced vital capacity <80 % predicted (OR = 2.9, p = 0.008) and lower body mass index (BMI) (OR for BMI = 0.9, p < 0.0005) at that visit, all of which are features associated with SSc disease activity and/or severity. Conclusions: While hypocomplementaemia is not associated with disease activity in patients with non-overlap SSc, it is associated with some features of increased SSc disease activity in patients with overlap disease features.James Esposito, Zoe Brown, Wendy Stevens, Joanne Sahhar, Candice Rabusa, Jane Zochling, Janet Roddy, Jennifer Walker, Susanna M. Proudman, and Mandana Nikpo

Epidemiology and disease characteristics of systemic sclerosis-related pulmonary arterial hypertension: results from a real-life screening programme

Pulmonary arterial hypertension (PAH) is the leading cause of death in systemic sclerosis (SSc). Annual screening with echocardiogram (ECHO) is recommended. We present the methodological aspects of a PAH screening programme in a large Australian SSc cohort, the epidemiology of SSc-PAH in this cohort, and an evaluation of factors influencing physician adherence to PAH screening guidelines.Patient characteristics and results of PAH screening were determined in all patients enrolled in a SSc longitudinal cohort study. Adherence to PAH screening guidelines was assessed by a survey of Australian rheumatologists. Summary statistics, chi-square tests, univariate and multivariable logistic regression were used to determine the associations of risk factors with PAH.Among 1636 patients with SSc, 194 (11.9%) had PAH proven by right-heart catheter. Of these, 160 were detected by screening. The annual incidence of PAH was 1.4%. Patients with PAH diagnosed on subsequent screens, compared with patients in whom PAH was diagnosed on first screen, were more likely to have diffuse SSc (p = 0.03), be in a better World Health Organisation (WHO) Functional Class at PAH diagnosis (p = 0.01) and have less advanced PAH evidenced by higher mean six-minute walk distance (p = 0.03), lower mean pulmonary arterial pressure (p = 0.009), lower mean pulmonary vascular resistance (p = 0.006) and fewer non-trivial pericardial effusions (p = 0.03). Adherence to annual PAH screening using an ECHO-based algorithm was poor among Australian rheumatologists, with less than half screening their patients with SSc of more than ten years disease duration.PAH is a common complication of SSc. Physician adherence to PAH screening recommendations remains poor. Identifying modifiable barriers to screening may improve adherence and ultimately patient outcomes.Kathleen Morrisroe, Wendy Stevens, Joanne Sahhar, Candice Rabusa, Mandana Nikpour, Susanna Proudman and the Australian Scleroderma Interest Group (ASIG

Multicentre randomised placebo-controlled trial of oral anticoagulation with apixaban in systemic sclerosis-related pulmonary arterial hypertension: the SPHInX study protocol

Introduction: Systemic sclerosis (SSc) is a severe and costly multiorgan autoimmune connective tissue disease characterised by vasculopathy and fibrosis. One of the major causes of SSc-related death is pulmonary arterial hypertension (PAH), which develops in 12–15% of patients with SSc and accounts for 30– 40% of deaths. In situ thrombosis in the small calibre peripheral pulmonary vessels resulting from endothelial dysfunction and an imbalance of anticoagulant and prothrombotic mediators has been implicated in the complex pathophysiology of SSc-related PAH (SSc- PAH), with international clinical guidelines recommending the use of anticoagulants for some types of PAH, such as idiopathic PAH. However, anticoagulation has not become part of standard clinical care for patients with SSc-PAH as only observational evidence exists to support its use. Therefore, we present the rationale and methodology of a phase III randomised controlled trial (RCT) to evaluate the efficacy, safety and cost-effectiveness of anticoagulation in SSc-PAH. Methods and analysis: This Australian multicentre RCT will compare 2.5 mg apixaban with placebo, in parallel treatment groups randomised in a 1:1 ratio, both administered twice daily for 3 years as adjunct therapy to stable oral PAH therapy. The composite primary outcome measure will be the time to death or clinical worsening of PAH. Secondary outcomes will include functional capacity, health-related quality of life measures and adverse events. A cost-effectiveness analysis of anticoagulation versus placebo will also be undertaken. Ethics and dissemination: Ethical approval for this RCT has been granted by the Human Research Ethics Committees of all participating centres. An independent data safety monitoring board will review safety and tolerability data for the duration of the trial. The findings of this RCT are to be published in open access journals.Alicia Calderone, Wendy Stevens, David Prior, Harshal Nandurkar, Eli Gabbay, Susanna M Proudman, Trevor Williams, David Celermajer, Joanne Sahhar, Peter K K Wong, Vivek Thakkar, Nathan Dwyer, Jeremy Wrobel, Weng Chin, Danny Liew, Margaret Staples, Rachelle Buchbinder, Mandana Nikpou

A comparison of the predictive accuracy of three screening models for pulmonary arterial hypertension in systemic sclerosis

Introduction: There is evidence that early screening for pulmonary arterial hypertension (PAH) in systemic sclerosis (SSc) improves outcomes. We compared the predictive accuracy of two recently published screening algorithms (DETECT 2013 and Australian Scleroderma Interest Group (ASIG) 2012) for SSc-associated PAH (SSc-PAH) with the commonly used European Society of Cardiology/European Respiratory Society (ESC/ERS 2009) guidelines. Methods: We included 73 consecutive SSc patients with suspected PAH undergoing right heart catheterization (RHC). The three screening models were applied to each patient. For each model, contingency table analysis was used to determine sensitivity, specificity, and positive (PPV) and negative (NPV) predictive values for PAH. These properties were also evaluated in an ‘alternate scenario analysis’ in which the prevalence of PAH was set at 10%. Results: RHC revealed PAH in 27 (36.9%) patients. DETECT and ASIG algorithms performed equally in predicting PAH with sensitivity and NPV of 100%. The ESC/ERS guidelines had sensitivity of 96.3% and NPV of only 91%, missing one case of PAH; these guidelines could not be applied to three patients who had absent tricuspid regurgitant (TR) jet. The ASIG algorithm had the highest specificity (54.5%). With PAH prevalence set at 10%, the NPV of the models was unchanged, but the PPV dropped to less than 20%. Conclusions: In this cohort, the DETECT and ASIG algorithms out-perform the ESC/ERS guidelines, detecting all patients with PAH. The ESC/ERS guidelines have limitations in the absence of a TR jet. Ultimately, the choice of SSc-PAH screening algorithm will also depend on cost and ease of application