Analysis of wall mass transfer in a turbulent pipe flow combining extended POD and FIK identity

We combine extended proper orthogonal decomposition (EPOD) together with the Fukagata-Iwamoto-Kasagi (FIK) identity to quantify the role of individual coherent structures on the wall mass transfer in a turbulent pipe flow. Direct numerical simulation at a Reynolds number of 5300 (based on bulk velocity) is performed with the passive scalar released at the pipe inlet. The proper orthogonal decomposition (POD) eigenvalues show that the scalar field can be described by a more compact set of modes compared to the velocity field, and that these modes are skewed towards higher azimuthal wave numbers. POD modes for the scalar and EPOD modes for the velocity are visualized in the cross-stream plane to infer the capacity of each mode to transport scalar to and from the wall. A form of the FIK identity is derived for the wall mass transfer coefficient (Sherwood number, Sh) and employed to separate the contributions of the mean and fluctuating velocity and scalar fields. The FIK decomposition shows that the turbulent velocity/scalar correlations account for up to 65.8% of the total Sh. The contribution of each POD and EPOD mode to the Sh number is also computed; it is found that, using azimuthal wave numbers m=1–15 and POD modes n=1–10, it is possible to reconstruct 49% of the turbulent component of Sh, with the velocity modes containing only 31% of the turbulent kinetic energy. Quadrant analysis shows that these modes are related to ejection and sweep events near the wall, with the ejection events dominating

On the Response of an OST to a Point-like Heat Source

A new technique of superconducting cavity diagnostics has been introduced by D. Hartrill at Cornell University, Ithaca, USA. Oscillating Superleak Transducers (OST) detect the heat transferred from a cavity's quench point via "Second Sound" through the superfluid He bath, needed to cool the superconducting cavity. The observed response of an OST is a complex, but reproducible pattern of oscillations. A small helium evaporation cryostat was built which allows the investigation of the response of an OST in greater detail. The distance between a point-like electrical heater and the OST can be varied. The OST can be mounted either parallel or perpendicular to the plate, housing the heat source. If the artificial quench-point releases an amount of energy compatible to a real quench spot on a cavity's surface, the OST signal starts with a negative pulse, which is usually strong enough to allow automatic detection. Furthermore, the reflection of the Second Sound on the wall is observed. A reflection coefficient R = 0.39 +- 0.05 of the glass wall is measured. This excludes a strong influence of multiple reflections in the complex OST response. Fourier analyses show three main frequencies, found in all OST spectra. They can be interpreted as modes of an oscillating circular membrane.Comment: 10 pages, 16 figure

Impact of Attention-Deficit/Hyperactivity Disorder (ADHD) on prescription dug spending for children and adolescents: increasing relevance of health economic evidence

<p>Abstract</p> <p>Background</p> <p>During the last decade, pharmaceutical spending for patients with attention-deficit-hyperactivity disorder (ADHD) has been escalating internationally.</p> <p>Objectives</p> <p>First, to estimate future trends of ADHD-related drug expenditures from the perspectives of the statutory health insurance (SHI; Gesetzliche Krankenversicherung, GKV) in Germany and the National Health Service (NHS) in England, respectively, for children and adolescents age 6 to 18 years. Second, to evaluate the budgetary impact on individual prescribers (child and adolescent psychiatrists and pediatricians treating patients with ADHD) in Germany.</p> <p>Methods</p> <p>A model was developed to predict plausible scenarios of future pharmaceutical expenditures for treatment of ADHD. Model inputs were derived from demographic and epidemiological data, a literature review of past spending trends, and an analysis of new pharmaceutical products in development for ADHD. Only products in clinical development phase III or later were considered. Uncertainty was addressed by way of scenario analysis. For each jurisdiction, five scenarios used different assumptions of future diagnosis prevalence, treatment prevalence, rates of adoption and unit costs of novel drugs, and treatment intensity.</p> <p>Results</p> <p>Annual ADHD pharmacotherapy expenditures for children and adolescents will further increase and may exceed €310 m (D; E: ₤78 m) in 2012 (2002: ~€21.8 m; ~₤7.0 m). During this period, overall drug spending by individual physicians may increase 2.3- to 9.5-fold, resulting from the multiplicative effects of four variables: increased number of diagnosed cases, growing acceptance and intensity of pharmacotherapy, and higher unit costs of novel medications.</p> <p>Discussion</p> <p>Even for an extreme low case scenario, a more than six-fold increase of pharmaceutical spending for children and adolescents is predicted over the decade from 2002 to 2012, from the perspectives of both the NHS in England and the GKV in Germany. This budgetary impact projection represents a partial analysis only because other expenditures are likely to rise as well, for instance those associated with physician services, including diagnosis and psychosocial treatment. Further to this, by definition budgetary impact analyses have little to nothing to say about clinical appropriateness and about value of money.</p> <p>Conclusion</p> <p>Providers of care for children and adolescents with ADHD should anticipate serious challenges related to the cost-effectiveness of interventions.</p

Moving Towards Accountability for Reasonableness – A Systematic Exploration of the Features of Legitimate Healthcare Coverage Decision-Making Processes Using Rare Diseases and Regenerative Therapies as a Case Study

Background: The accountability for reasonableness (A4R) framework defines 4 conditions for legitimate healthcare coverage decision processes: Relevance, Publicity, Appeals, and Enforcement. The aim of this study was to reflect on how the diverse features of decision-making processes can be aligned with A4R conditions to guide decision-making towards legitimacy. Rare disease and regenerative therapies (RDRTs) pose special decision-making challenges and offer therefore a useful case study. Methods: Features operationalizing each A4R condition as well as three different approaches to address these features (cost-per-QALY-focused and multicriteria-based) were defined and organized into a matrix. Seven experts explored these features during a panel run under the Chatham House Rule and provided general and RDRT-specific recommendations. Responses were analyzed to identify converging and diverging recommendations. Results: Regarding Relevance, recommendations included supporting deliberation, stakeholder participation and grounding coverage decision criteria in normative and societal objectives. Thirteen of 17 proposed decision criteria were recommended by a majority of panelists. The usefulness of universal cost-effectiveness thresholds to inform allocative efficiency was challenged, particularly in the RDRT context. RDRTs raise specific issues that need to be considered; however, rarity should be viewed in relation to other aspects, such as disease severity and budget impact. Regarding Publicity, panelists recommended transparency about the values underlying a decision and value judgements used in selecting evidence. For Appeals, recommendations included a life-cycle approach with clear provisions for re-evaluations. For Enforcement, external quality reviews of decisions were recommended. Conclusion: Moving coverage decision-making processes towards enhanced legitimacy in general and in the RDRT context involves designing and refining approaches to support participation and deliberation, enhancing transparency, and allowing explicit consideration of multiple decision criteria that reflect normative and societal objectives

The role of enzyme replacement therapy in severe Hunter syndrome—an expert panel consensus

Intravenous enzyme replacement therapy (ERT) with idursulfase for Hunter syndrome has not been demonstrated to and is not predicted to cross the blood–brain barrier. Nearly all published experience with ERT with idursulfase has therefore been in patients without cognitive impairment (attenuated phenotype). Little formal guidance is available on the issues surrounding ERT in cognitively impaired patients with the severe phenotype. An expert panel was therefore convened to provide guidance on these issues. The clinical experience of the panel with 66 patients suggests that somatic improvements (e.g., reduction in liver volume, increased mobility, and reduction in frequency of respiratory infections) may occur in most severe patients. Cognitive benefits have not been seen. It was agreed that, in general, severe patients are candidates for at least a 6–12-month trial of ERT, excluding patients who are severely neurologically impaired, those in a vegetative state, or those who have a condition that may lead to near-term death. It is imperative that the treating physician discuss the goals of treatment, methods of assessment of response, and criteria for discontinuation of treatment with the family before ERT is initiated. Conclusion: The decision to initiate ERT in severe Hunter syndrome should be made by the physician and parents and must be based on realistic expectations of benefits and risks, with the understanding that ERT may be withdrawn in the absence of demonstrable benefits

Bridging health technology assessment (HTA) with multicriteria decision analyses (MCDA): field testing of the EVIDEM framework for coverage decisions by a public payer in Canada

<p>Abstract</p> <p>Background</p> <p>Consistent healthcare decisionmaking requires systematic consideration of decision criteria and evidence available to inform them. This can be tackled by combining multicriteria decision analysis (MCDA) and Health Technology Assessment (HTA). The objective of this study was to field-test a decision support framework (EVIDEM), explore its utility to a drug advisory committee and test its reliability over time.</p> <p>Methods</p> <p>Tramadol for chronic non-cancer pain was selected by the health plan as a case study relevant to their context. Based on extensive literature review, a by-criterion HTA report was developed to provide synthesized evidence for each criterion of the framework (14 criteria for the MCDA Core Model and 6 qualitative criteria for the Contextual Tool). During workshop sessions, committee members tested the framework in three steps by assigning: 1) weights to each criterion of the MCDA Core Model representing individual perspective; 2) scores for tramadol for each criterion of the MCDA Core Model using synthesized data; and 3) qualitative impacts of criteria of the Contextual Tool on the appraisal. Utility and reliability of the approach were explored through discussion, survey and test-retest. Agreement between test and retest data was analyzed by calculating intra-rater correlation coefficients (ICCs) for weights, scores and MCDA value estimates.</p> <p>Results</p> <p>The framework was found useful by the drug advisory committee in supporting systematic consideration of a broad range of criteria to promote a consistent approach to appraising healthcare interventions. Directly integrated in the framework as a "by-criterion" HTA report, synthesized evidence for each criterion facilitated its consideration, although this was sometimes limited by lack of relevant data. Test-retest analysis showed fair to good consistency of weights, scores and MCDA value estimates at the individual level (ICC ranging from 0.676 to 0.698), thus lending some support for the reliability of the approach. Overall, committee members endorsed the inclusion of most framework criteria and revealed important areas of discussion, clarification and adaptation of the framework to the needs of the committee.</p> <p>Conclusions</p> <p>By promoting systematic consideration of all decision criteria and the underlying evidence, the framework allows a consistent approach to appraising healthcare interventions. Further testing and validation are needed to advance MCDA approaches in healthcare decisionmaking.</p

ADHD symptomatology in eating disorders : a secondary psychopathological measure of severity?

Background: Attention-deficit/hyperactivity disorder (ADHD) has commonly been described in psychiatric disorders. Although several studies have found positive associations between abnormal eating patterns during childhood and ADHD, there is a lack of studies on ADHD and Eating Disorders (ED). The aims of this exploratory study were 1) to assess the ADHD symptoms level in ED and to ascertain whether there are differences among ED subtypes; 2) to analyze whether the presence of ADHD symptoms is associated with more severe eating disorder symptoms and greater general psychopathology; and 3) to assess whether the ADHD symptoms level is associated with specific temperament and character traits. Methods: 191 female ED patients were included. Assessment was carried out with the EDI-2, ASRS-v1.1, the SCL-90-R and the TCI-R. Results: The ADHD symptoms level was similar in bulimia, eating disorder not otherwise specified and binge eating subtypes, and lower in anorexic patients. Obsessiveness and Hostility were significantly positively associated with ADHD symptoms. A path model showed that ADHD was associated with high Novelty Seeking and low Self-Directedness, whereas ED severity was influenced by ADHD severity and low Self-Directedness. Conclusions: Bingeing/purging ED subtypes have a high ADHD symptoms level, also related with more severe eating, general and personality psychopathology

Recommendations from the European Working Group for Value Assessment and Funding Processes in Rare Diseases (ORPH-VAL)

International audienceAbstractRare diseases are an important public health issue with high unmet need. The introduction of the EU Regulation on orphan medicinal products (OMP) has been successful in stimulating investment in the research and development of OMPs. Despite this advancement, patients do not have universal access to these new medicines. There are many factors that affect OMP uptake, but one of the most important is the difficulty of making pricing and reimbursement (P&R) decisions in rare diseases. Until now, there has been little consensus on the most appropriate assessment criteria, perspective or appraisal process. This paper proposes nine principles to help improve the consistency of OMP P&R assessment in Europe and ensure that value assessment, pricing and funding processes reflect the specificities of rare diseases and contribute to both the sustainability of healthcare systems and the sustainability of innovation in this field. These recommendations are the output of the European Working Group for Value Assessment and Funding Processes in Rare Diseases (ORPH-VAL), a collaboration between rare disease experts, patient representatives, academics, health technology assessment (HTA) practitioners, politicians and industry representatives. ORPH-VAL reached its recommendations through careful consideration of existing OMP P&R literature and through a wide consultation with expert stakeholders, including payers, regulators and patients. The principles cover four areas: OMP decision criteria, OMP decision process, OMP sustainable funding systems and European co-ordination. This paper also presents a guide to the core elements of value relevant to OMPs that should be consistently considered in all OMP appraisals. The principles outlined in this paper may be helpful in drawing together an emerging consensus on this topic and identifying areas where consistency in payer approach could be achievable and beneficial. All stakeholders have an obligation to work together to ensure that the promise of OMP’s is realised