66 research outputs found

    General Strategy for Broadband Coherent Perfect Absorption and Multi-wavelength All-optical Switching Based on Epsilon-Near-Zero Multilayer Films

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    We propose a general, easy-to-implement scheme for broadband coherent perfect absorption (CPA) using epsilon-near-zero (ENZ) multilayer films. Specifically, we employ indium tin oxide (ITO) as a tunable ENZ material, and theoretically investigate CPA in the near-infrared region. We first derive general CPA conditions using the scattering matrix and the admittance matching methods. Then, by combining these two methods, we extract analytic expressions for all relevant parameters for CPA. Based on this theoretical framework, we proceed to study ENZ CPA in a single layer ITO film and apply it to all-optical switching. Finally, using an ITO multilayer of different ENZ wavelengths, we implement broadband ENZ CPA structures and investigate multi-wavelength all-optical switching in the technologically important telecommunication window. In our design, the admittance matching diagram was employed to graphically extract not only the structural parameters (the film thicknesses and incident angles), but also the input beam parameters (the irradiance ratio and phase difference between two input beams). We find that the multi-wavelength all-optical switching in our broadband ENZ CPA system can be fully controlled by the phase difference between two input beams. The simple but general design principles and analyses in this work can be widely used in various thin-film devicesopen

    Trends and inequity in improved sanitation facility utilisation in Bangladesh: evidence from Bangladesh demographic and health surveys

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    Improved sanitation is indispensable to human health. However, lack of access to improved sanitation remains one of the most daunting public health challenges of the twenty-first century in Bangladesh. The aim of the study was to describe the trends in access to improved sanitation facilities following the inequity gap among households in different socioeconomic groups in Bangladesh. Data from the Bangladesh Demographic and Health Survey (BDHS) 2007, 2011, 2014, and 2017-18 were extracted for this study. Inequity in access to improved sanitation was calculated using rich-poor ratio and concentration index to determine the changes in inequity across the time period. In Bangladesh, the proportion of households with access to improved sanitation increased steadily from 25.4% to 45.4% between 2007 and 2014, but slightly decreased to 44.0% in 2017-18. Age, educational status, marital status of household head, household wealth index, household size, place of residence, division, and survey year were significantly associated with the utilisation of improved sanitation. There is a pro-rich situation, which means that utilisation of improved sanitation was more concentrated among the rich across all survey years (Concentration Index ranges: 0.40 to 0.27). The government and other relevant stakeholders should take initiatives considering inequity among different socioeconomic groups to ensure the use of improved sanitation facilities for all, hence achieving universal health coverage

    Women, men, and rheumatoid arthritis: analyses of disease activity, disease characteristics, and treatments in the QUEST-RA Study

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    Introduction Gender as a predictor of outcomes of rheumatoid arthritis (RA) has evoked considerable interest over the decades. Historically, there is no consensus whether RA is worse in females or males. Recent reports suggest that females are less likely than males to achieve remission. Therefore, we aimed to study possible associations of gender and disease activity, disease characteristics, and treatments of RA in a large multinational cross-sectional cohort of patients with RA called Quantitative Standard Monitoring of Patients with RA (QUEST-RA). Methods The cohort includes clinical and questionnaire data from patients who were seen in usual care, including 6,004 patients at 70 sites in 25 countries as of April 2008. Gender differences were analyzed for American College of Rheumatology Core Data Set measures of disease activity, DAS28 (disease activity score using 28 joint counts), fatigue, the presence of rheumatoid factor, nodules and erosions, and the current use of prednisone, methotrexate, and biologic agents. Results Women had poorer scores than men in all Core Data Set measures. The mean values for females and males were swollen joint count-28 (SJC28) of 4.5 versus 3.8, tender joint count-28 of 6.9 versus 5.4, erythrocyte sedimentation rate of 30 versus 26, Health Assessment Questionnaire of 1.1 versus 0.8, visual analog scales for physician global estimate of 3.0 versus 2.5, pain of 4.3 versus 3.6, patient global status of 4.2 versus 3.7, DAS28 of 4.3 versus 3.8, and fatigue of 4.6 versus 3.7 (P LT 0.001). However, effect sizes were small-medium and smallest (0.13) for SJC28. Among patients who had no or minimal disease activity (0 to 1) on SJC28, women had statistically significantly higher mean values compared with men in all other disease activity measures (P LT 0.001) and met DAS28 remission less often than men. Rheumatoid factor was equally prevalent among genders. Men had nodules more often than women. Women had erosions more often than men, but the statistical significance was marginal. Similar proportions of females and males were taking different therapies. Conclusions In this large multinational cohort, RA disease activity measures appear to be worse in women than in men. However, most of the gender differences in RA disease activity may originate from the measures of disease activity rather than from RA disease activity itself

    A survey of trainee specialists experiences at the University of Cape Town (UCT): Impacts of race and gender

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    <p>Abstract</p> <p>Background</p> <p>Efforts to redress racial and gender inequalities in the training of medical specialists has been a central part of a dedicated programme in the Faculty of Health Sciences at the University of Cape Town (UCT). This study aimed to describe trends in race and gender profiles of postgraduate students in medical specialties (registrars) from 1999 to 2006 and to identify factors affecting recruitment and retention of black and female trainees.</p> <p>Method</p> <p>Review of faculty databases for race and gender data from 1999 to 2006. Distribution of an anonymous self-administered questionnaire to all registrars in 2005/2006.</p> <p>Results</p> <p>The percentage of African registrars doubled from 10% to 19% from 1999 to beyond 2002. The percentages of Africans, Coloureds and Indians rose steadily from 26% to 46% from 1999 to 2005, as did that of women from 27% to 44%. The institution's perceived good reputation, being an alumnus and originating from Cape Town were common reasons for choosing UCT for training. A quarter of respondents reported knowledge of a friend who decided against studying at UCT for reasons which included anticipated racial discrimination. Black respondents (23%), particularly African (50%), were more likely to describe registrarship at UCT as unwelcoming than white respondents (12%). Specific instances of personal experience of discrimination were uncommon and not associated with respondents' race or gender. Registrars who had had a child during registrarship and those reporting discrimination were more likely to rate the learning and research environment as poor (Odds Ratio, 4.01; 95% CI 0.98 – 16.47 and 1.99 95% CI 0.57 – 6.97, respectively).</p> <p>Conclusion</p> <p>The proportion of black and female registrars at the University of Cape Town has increased steadily from 1999 to 2006, most likely a result of systematic equity policies and procedures adopted in the faculty during this period. The data point to a need for policies to make the institution more welcoming to diversity and for strategies to address institutional culture and mentorship, with an aim to develop examples of best practices to share within and between institutions.</p

    Treatment of rheumatoid arthritis: a global perspective on the use of antirheumatic drugs

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    Modern therapy for rheumatoid arthritis (RA) is based on knowledge of the severity of the natural history of the disease. RA patients are approached with early and aggressive treatment strategies, methotrexate as an anchor drug, biological targeted therapies in those with inadequate response to methotrexate, and “tight control,” aiming for remission and low disease activity according to quantitative monitoring. This chapter presents a rationale for current treatment strategies for RA with antirheumatic drugs, a review of published reports concerning treatments in clinical cohorts outside of clinical trials, and current treatments at 61 sites in 21 countries in the QUEST-RA database

    Barriers to achieving controlled rheumatoid arthritis in the United Arab Emirates: a cross-sectional study

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    To better understand the factors that affect low disease activity (DAS28 ≤ 3.2, LDA) in rheumatoid arthritis (RA) and barriers within the UAE, demographic/treatment data and DAS28 scores were collected through chart reviews of 182 consecutive RA patients seen at a private clinic in Dubai over a 2-month period. Patients were separated into a LDA group and a group comprised of moderate (3.2 < DAS28 < 5.1) or high disease activity (DAS28 ≥ 5.1) (MHDA). We then examined variables that may be associated with LDA and re-examined the MHDA group for barriers. While 97 (53 %) of the 182 patients had achieved the treatment target of DAS28 ≤ 3.2, 85 (47 %) had MHDA. A significantly larger portion of LDA patients had been previously treated with sulfasalazine (36 in LDA vs. 14 in MHDA, P = 0.002) or was presently on biological treatments (24 vs. 9, P = 0.013). For the 85 MHDA patients, 40 (22 % of 182) exhibited resistant disease with 25 (13.7 % of 182) failing their current first tier disease-modifying anti-rheumatic drug (DMARD) treatment or combinations and 15 (8.2 % of 182) failing current anti-TNF or biologic treatment. Reasons listed were primarily socioeconomic with 40 % of the resistant disease group unable to afford biologicals and 52 % of the patient-driven preference group discontinuing DMARDs against professional advice. Going forward, emphasis on the agreement between patient and rheumatologist on treatment, specifically regarding how DMARDs help relieve symptoms and their proper use, could help reduce the percentage of MHDA patients in the UAE
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