10 research outputs found

    Hydrodynamics of domain growth in nematic liquid crystals

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    We study the growth of aligned domains in nematic liquid crystals. Results are obtained solving the Beris-Edwards equations of motion using the lattice Boltzmann approach. Spatial anisotropy in the domain growth is shown to be a consequence of the flow induced by the changing order parameter field (backflow). The generalization of the results to the growth of a cylindrical domain, which involves the dynamics of a defect ring, is discussed.Comment: 12 revtex-style pages, including 12 figures; small changes before publicatio

    Adalimumab for non-infectious uveitis: is it cost-effective?

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    BACKGROUND/AIMS: Uveitis is inflammation inside the eye. Our objective was to assess the cost-effectiveness of adalimumab compared with current practice (immunosuppressants and systemic corticosteroids) in patients with non-infectious intermediate, posterior or panuveitis and to identify areas for future research. METHODS: A Markov model was built to estimate costs and benefits of the interventions. Systematic reviews were performed to identify the available relevant clinical and cost-effectiveness evidence. Data collected in two key randomised controlled trials (VISUAL I and VISUAL II) were used to estimate the interventions' effectiveness compared with the trials' comparator arms (placebo plus limited current practice (LCP)). The analysis was performed from the National Health Service and Personal Social Services perspective. Costs were calculated based on standard UK sources. RESULTS: The estimated incremental cost-effectiveness ratios (ICERs) of adalimumab versus LCP for the base case are £92 600 and £318 075 per quality-adjusted life year (QALY) gained for active and inactive uveitis, respectively. In sensitivity analyses, the ICER varied from £15 579 to £120 653 and £35 642 to £800 775 per QALY for active and inactive uveitis. CONCLUSION: The estimated ICERs of adalimumab versus LCP are above generally accepted thresholds for cost-effectiveness in the UK. Adalimumab may be more cost-effective in patients with active uveitis at greater risk of blindness. However, there is an unmet need for additional primary data to provide more reliable estimates in several important areas, including effectiveness of adalimumab versus current practice (instead of LCP), incidence of long-term blindness, adalimumab effectiveness in avoiding blindness, and rates and time to remission while on adalimumab

    Dexamethasone implant for non-infectious uveitis: is it cost-effective?

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    BACKGROUND: Uveitis is inflammation inside the eye. The objective of this study is to assess the cost-effectiveness of a dexamethasone implant plus current practice (immunosuppressants and systemic corticosteroids) compared with current practice alone, in patients with non-infectious intermediate, posterior or pan-uveitis and to identify areas for future research. METHODS: A Markov model was built to estimate the costs and benefits of dexamethasone. Systematic reviews were performed to identify available relevant evidence. Quality of life data from the key randomised-controlled trial (HURON) was used to estimate the interventions' effectiveness compared with the trial's comparator arm (placebo plus limited current practice (LCP)). The analysis took a National Health Service and Personal Social Services perspective. Costs were calculated based on standard UK sources. RESULTS: The incremental cost-effectiveness ratio (ICER) of one dexamethasone implant compared with LCP is estimated as £19 509 per quality-adjusted life year (QALY) gained. The factors with the largest impact on the results were rate of blindness and relative proportion of blindness cases avoided by dexamethasone. Using plausible alternative assumptions, dexamethasone could be cost saving or it may be associated with an ICER of £56 329 per QALY gained compared with LCP. CONCLUSIONS: Dexamethasone is estimated to be cost-effective using generally accepted UK thresholds. However, there is substantial uncertainty around these results due to scarcity of evidence. Future research on the following would help provide more reliable estimates: effectiveness of dexamethasone versus current practice (instead of LCP), with subgroup analyses for unilateral and bilateral uveitis, incidence of long-term blindness and effectiveness of dexamethasone in avoiding blindness

    Reporting guideline for the early stage clinical evaluation of decision support systems driven by artificial intelligence: DECIDE-AI

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    A growing number of artificial intelligence (AI)-based clinical decision support systems are showing promising performance in preclinical, in silico, evaluation, but few have yet demonstrated real benefit to patient care. Early stage clinical evaluation is important to assess an AI system’s actual clinical performance at small scale, ensure its safety, evaluate the human factors surrounding its use, and pave the way to further large scale trials. However, the reporting of these early studies remains inadequate. The present statement provides a multistakeholder, consensus-based reporting guideline for the Developmental and Exploratory Clinical Investigations of DEcision support systems driven by Artificial Intelligence (DECIDE-AI). We conducted a two round, modified Delphi process to collect and analyse expert opinion on the reporting of early clinical evaluation of AI systems. Experts were recruited from 20 predefined stakeholder categories. The final composition and wording of the guideline was determined at a virtual consensus meeting. The checklist and the Explanation & Elaboration (E&E) sections were refined based on feedback from a qualitative evaluation process. 123 experts participated in the first round of Delphi, 138 in the second, 16 in the consensus meeting, and 16 in the qualitative evaluation. The DECIDE-AI reporting guideline comprises 17 AI specific reporting items (made of 28 subitems) and 10 generic reporting items, with an E&E paragraph provided for each. Through consultation and consensus with a range of stakeholders, we have developed a guideline comprising key items that should be reported in early stage clinical studies of AI-based decision support systems in healthcare. By providing an actionable checklist of minimal reporting items, the DECIDE-AI guideline will facilitate the appraisal of these studies and replicability of their findings

    Generalized lattice boltzmann algorithm for the flow of a nematic liquid crystal with variable order parameter

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    A lattice Boltzmann (LB) scheme is described, which recovers the equations developed by Qian-Sheng for the hydrodynamics of a nematic liquid crystal with a tensor order parameter. The standard mesoscopic LB scalar density is generalized to a tensor quantity and the macroscopic momentum, density, and tensor order parameter are recovered from appropriate moments of this mesoscopic density. A single lattice Boltzmann equation is used with a direction dependent Bhatnagar, Gross, and Krook (BGK) collision term, with additional forcing terms to recover the antisymmetric terms in the stress tensor. A Chapman-Enskog analysis is presented, which demonstrates that the Qian-Sheng scheme is recovered, provided a lattice with sixth-order isotropy is used. The method is validated against analytical results for a number of cases including flow alignment of the order tensor and the Miesowicz viscosities in the presence of an aligning magnetic field. The algorithm accurately recovers the predicted changes in the order parameter in the presence of aligning flow, and magnetic, fields. Preliminary results are given for an extension of the method to model the interface between isotropic and nematic fluids.</p

    The Collaborative Ocular Tuberculosis Study (COTS) Consensus (CON) Group Meeting Proceedings

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    An international, expert led consensus initiative was set up by the Collaborative Ocular Tuberculosis Study (COTS) group to develop systematic, evidence, and experience-based recommendations for the treatment of ocular TB using a modified Delphi technique process. In the first round of Delphi, the group identified clinical scenarios pertinent to ocular TB based on five clinical phenotypes (anterior uveitis, intermediate uveitis, choroiditis, retinal vasculitis, and panuveitis). Using an interactive online questionnaires, guided by background knowledge from published literature, 486 consensus statements for initiating ATT were generated and deliberated amongst 81 global uveitis experts. The median score of five was considered reaching consensus for initiating ATT. The median score of four was tabled for deliberation through Delphi round 2 in a face-to-face meeting. This report describes the methodology adopted and followed through the consensus process, which help elucidate the guidelines for initiating ATT in patients with choroidal TB. © 2020 Taylor & Francis Group, LLC
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