25 research outputs found

    Experimental investigation of high-power laser irradiation of missile materials in subsonic and supersonic flows

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    The technology of missiles and of their countermeasures is evolving continuously. High-power lasers are an option to encounter these threats. In order to understand their potential in such a scenario, it is vital to investigate the laser effects in the presence of a corresponding aerodynamic environment. Thus, experimental and numerical investigations were conducted cooperatively by Fraunhofer Ernst-Mach-Institut and the supersonic and hypersonic technologies department of DLR. An ytterbium fiber laser system was installed at the supersonic wind tunnel VMK. The laboratory was fit to meet necessary laser safety requirements. Combined subsonic and supersonic flow and high-power laser experiments with flow velocities up to a Mach number of three and a laser power up to 10 kW were realized. Two kind of tests were performed, focusing on laser beam distortion through aero-optical effects and on high-power laser effects, respectively. The interaction effects between aerodynamics, laser radiation and irradiated targets were studied on flat-plates as well as cylindrical and radome targets, simulating generic missile design. Irradiated objects consisted of steel, aluminum, carbon-fiber-reinforced polymer and the ceramic-based composite WHIPOX. While beam distortions were studied with a wavefront sensor, damaging processes were investigated by measuring the perforation time of the targets, as well as via high-speed imaging, thermography as well as Schlieren imaging. Numerical three-dimensional, steady, and uncoupled simulations were performed. The data indicated complex interactions between material, laser beam, and aerodynamics. This investigation can be used as an initial basis for further analysis of laser-material-aerodynamic interactions with respect to missile defense

    Electronic polarization in pentacene crystals and thin films

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    Electronic polarization is evaluated in pentacene crystals and in thin films on a metallic substrate using a self-consistent method for computing charge redistribution in non-overlapping molecules. The optical dielectric constant and its principal axes are reported for a neutral crystal. The polarization energies P+ and P- of a cation and anion at infinite separation are found for both molecules in the crystal's unit cell in the bulk, at the surface, and at the organic-metal interface of a film of N molecular layers. We find that a single pentacene layer with herring-bone packing provides a screening environment approaching the bulk. The polarization contribution to the transport gap P=(P+)+(P-), which is 2.01 eV in the bulk, decreases and increases by only ~ 10% at surfaces and interfaces, respectively. We also compute the polarization energy of charge-transfer (CT) states with fixed separation between anion and cation, and compare to electroabsorption data and to submolecular calculations. Electronic polarization of ~ 1 eV per charge has a major role for transport in organic molecular systems with limited overlap.Comment: 10 revtex pages, 6 PS figures embedde

    Collaborative Ambulatory Orthopaedic Care in Patients with Hip and Knee Osteoarthritis: A Retrospective Comparative Cohort Study on Health Utilisation and Economic Outcomes

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    Objective: To evaluate a novel healthcare programme for the treatment of patients with hip and knee osteoarthritis in southern Germany in terms of clinical and health economic outcomes. The study is based on claims data from 2014 to 2017. Methods: We conducted a retrospective comparative cohort study of 9768 patients with hip and knee osteoarthritis, of whom 9231 were enrolled in a collaborative ambulatory orthopaedic care programme (intervention group), and 537 patients received usual orthopaedic care (control group). Key features of the programme are coordinated care, morbidity-adapted reimbursement and extended consultation times. Multivariable analysis was performed to determine effects on health utilisation outcomes. The economic analysis considered annual costs per patient from a healthcare payer perspective, stratified by healthcare service sector. Besides multivariable regression analyses, bootstrapping was used to estimate confidence intervals for predicted mean costs by group. Results: Musculoskeletal-disease-related hospitalisation was much less likely among intervention group patients than control group patients [odds ratio (OR): 0.079; 95% CI: 0.062–0.099]. The number of physiotherapy prescriptions per patient was significantly lower in the intervention group (RR: 0.814; 95% CI: 0.721–0.919), while the likelihood of participation in exercise programmes over one year was significantly higher (OR: 3.126; 95% CI: 1.604–6.094). Enrolment in the programme was associated with significantly higher ambulatory costs (€1048 vs. €925), but costs for inpatient care, including hospital stays, were significantly lower (€1003 vs. €1497 and €928 vs. €1300 respectively). Overall annual cost-savings were €195 per patient. Conclusions: Collaborative ambulatory orthopaedic care was associated with reduced hospitalisation in patients with hip and knee osteoarthritis. Health costs for programme participants were lower overall, despite higher costs for ambulatory care

    Social selling : a study of the status quo in Germany

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    In the lights of an increasing digitalization of companies, the sales process might experience changes in the usage and the influence of digital tools. In order to examine the status quo of German companies in this regard, a study was conducted between 235 participants. The results of this study will be outlined in the article at hand

    Health State Utility Values Used in Economic Evaluation of Meningococcal Vaccination: A Systematic Review

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    Witte J, Gruhn S, Wick M, Damm O, Greiner W. Health State Utility Values Used in Economic Evaluation of Meningococcal Vaccination: A Systematic Review. In: ISPOR Europe 2022 Abstracts. Value in Health. Vol 25. New York: Elsevier; 2022: S107.Objectives Invasive meningococcal disease (IMD) is a major public health challenge associated with high case-fatality and life-long disabilities in survivors. Approximately 20% of survivors suffer at least one disability, including physical, neurological and psychological sequalae. Health state utility values (HSUVs) are needed to assess associated health outcomes in economic evaluations of new vaccines. This study aims to give a structured overview of HSUVs used in meningococcal vaccination Methods We systematically searched PubMed and EMBASE for economic evaluations of meningococcal vaccination published until January 15, 2022. The review focused on type, value, and source of reported HSUVs and is presented following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology. Results A total of 29 publications were included. Eighteen models examined MenB vaccination strategies, 11 MenC/MenACWY vaccination. Utility data were reported for both, acute disease and sequalae, while reporting of the utilities used often showed weaknesses (e.g., unclear or inaccurate sources). HSUVs applied for the acute phase ranged from -0.51 to 0.860. Considered sequalae included physical (n=22/29), neurological (21/29), or psychological/behavioral sequalae (6/29). Utility data on sequalae were Conclusions There are reporting gaps and weaknesses in the current evidence base for utilities used in economic models of meningococcal vaccination. Transparent evaluation and reporting of utility data are essential in economic evaluation. As caregiver spillover utilities and QALY adjustment factors enable consideration of the societal preference for interventions that prevent rare, but severe diseases, they should be evaluated in models and be discussed with decision-making bodies

    Secondary Prevention via Case Managers in Stroke Patients: A Cost-Effectiveness Analysis of Claims Data from German Statutory Health Insurance Providers

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    Duevel JA, Gruhn S, Grosser J, Elkenkamp S, Greiner W. Secondary Prevention via Case Managers in Stroke Patients: A Cost-Effectiveness Analysis of Claims Data from German Statutory Health Insurance Providers. Healthcare. 2024;12(11): 1157.Strokes remain a leading cause of death and disability worldwide. The STROKE OWL study evaluated a novel case management approach for patients with stroke (modified Rankin Scale 0–4) or transient ischemic attack (TIA) who received support across healthcare settings and secondary prevention training from case managers for one year. The primary aim of this quasi-experimental study was a reduction in stroke recurrence. Here, we report the results of a health economic analysis of the STROKE OWL study, conducted in accordance with CHEERS guidelines. The calculations were based on claims data of cooperating statutory health insurance companies. In addition to a regression analysis for cost comparison, the incremental cost-effectiveness ratio was determined, and a probabilistic sensitivity analysis was carried out. In total, 1167 patients per group were included in the analysis. The intervention group incurred 32.3% higher direct costs (p < 0.001) than the control group. With a difference of EUR 1384.78 (95% CI: [1.2384–1.4143], p < 0.0001) and a 5.32% increase in hazards for the intervention group (HR = 1.0532, 95% CI: [0.7869–1.4096], p = 0.7274) resulting in an ICER of EUR 260.30, we found that the case management intervention dominated in the total stroke population, even for an arbitrarily high willingness to pay. In the TIA subgroup, however, the intervention was cost-effective even for a low willingness to pay. Our results are limited by small samples for both TIA and severe stroke patients and by claims data heterogeneity for some cost components, which had to be excluded from the analysis. Future research should investigate the cost-effectiveness of case management interventions for both severe stroke and TIA populations using appropriate data

    EFFECTS OF ADOLESCENT MENACWY AND MENC VACCINATION IN GERMANY: A MODELLING STUDY

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    Gruhn S, Batram M, Wick M, Langevin E, Scholz S, Damm O. EFFECTS OF ADOLESCENT MENACWY AND MENC VACCINATION IN GERMANY: A MODELLING STUDY. Value in Health. 2023;26(12, Suppl. ):S248-S249

    Epidemiology and economic burden of meningococcal disease in Germany: A systematic review

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    Gruhn S, Witte J, Greiner W, et al. Epidemiology and economic burden of meningococcal disease in Germany: A systematic review. Vaccine. 2022;40(13):1932-1947.INTRODUCTION: Invasive meningococcal disease (IMD) is a notifiable disease in Germany and other European countries. Due to the high lethality of the disease and the risk of long-term consequences, IMD prevention is of high public health relevance despite the low number of cases in the population. This study aims to describe key epidemiological and economic parameters of IMD in Germany to support national decision-making processes for implementing enhanced prevention measures.; METHODS: Based on a systematic literature review in PubMed and EMBASE, all publications on the burden of disease and costs of IMD published up to May 2020 were evaluated. Additionally, notification data were used to report the annual case numbers and incidence of IMD in Germany until the end of 2019.; RESULTS: Thirty-six studies were included, of which 35 reported data on the epidemiological burden of disease and three reported data on economic aspects of IMD. The type of reported endpoints and results on the incidence of IMD differed widely by reporting year, population, and data source used. Most of the data are reported without specific information about a serogroup. Data on the economic burden of disease and healthcare resource use are scarce. Based on mandatory notification data, a decrease in the incidence of notified IMD cases has been observed since 2004. Currently, the nationwide annual incidence in Germany is at 0.3 cases per 100,000 persons and has gradually decreased. While the overall decline is mainly attributable to MenB, cases with MenY and MenW are the only ones that have increased on a low level in recent years.; CONCLUSION: While IMD is a rare disease, high direct and indirect costs illustrate the relevance of the disease for patients, caregivers, as well as for the health care system. Future research should concentrate on quantifying the long-term economic burden and indirect costs of meningococcal disease. Integrated IMD surveillance with isolate characterisation remains crucial to inform public health policies. Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved

    Modelling the Public Health Impact of MenACWY and MenC Adolescent Vaccination Strategies in Germany

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    Gruhn S, Batram M, Wick M, et al. Modelling the Public Health Impact of MenACWY and MenC Adolescent Vaccination Strategies in Germany. Infectious Diseases and Therapy . 2024.INTRODUCTION: Invasive meningococcal disease (IMD) causes significant mortality and long-term sequelae. This study assesses the potential public health impact of adolescent vaccination strategies employing MenACWY and MenC vaccines in Germany, where the existing meningococcal immunisation programme predominantly involves MenC administration in toddlers.; METHODS: A dynamic transmission model was developed to simulate the carriage of five meningococcal serogroup compartments (AY/B/C/W/Other) from 2019 until 2060 within 1-year age groups from 0 to 99 years of age. IMD cases were estimated based on case-carrier ratios. The model considered vaccine effectiveness against carriage acquisition and IMD.; RESULTS: The model predicts that introducing MenACWY adolescent vaccination could lead to a considerable reduction in IMD incidence, with the potential to prevent up to 65 cases per year and a cumulative total of 1467 cases by 2060. This decrease, mainly driven by herd effects, would result in a reduction of IMD incidence across all age groups, regardless of vaccination age. Furthermore, implementing MenACWY vaccination in adolescents is projected to decrease annual MenACWY-related IMD mortality by up to 64%, equating to an overall prevention of 156 IMD deaths by 2060. These protective outcomes are expected to culminate in approximately 2250 life years gained (LYG) throughout the model's projected time horizon. In contrast, the adoption of MenC vaccination in adolescents is predicted to have minimal influence on both IMD incidence and mortality, as well as on LYG.; CONCLUSION: The results of this study demonstrate that implementing MenACWY vaccination for adolescents in Germany is likely to notably reduce IMD incidence and mortality across age groups. However, the introduction of MenC adolescent vaccination shows only limited impact. Considering the extensive healthcare resources typically required for IMD management, these findings suggest the potential for economic benefits associated with the adoption of MenACWY adolescent vaccination, warranting further cost-effectivenessanalysis. © 2024. The Author(s)

    SALUS-a non-inferiority trial to compare self-tonometry in glaucoma patients with regular inpatient intraocular pressure controls: study design and set-up

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    Oldiges K, Steinmann M, Düvel J, et al. SALUS-a non-inferiority trial to compare self-tonometry in glaucoma patients with regular inpatient intraocular pressure controls: study design and set-up. Graefes Archive for Clinical and Experimental Ophthalmology. 2022.PURPOSE: The SALUS study aims to improve the healthcare situation for glaucoma patients in Germany. In order to detect diurnal intraocular pressure (IOP) fluctuations, inpatient monitoring of IOP in an eye hospital for a minimum of 24h is the current standard. SALUS assesses the benefits of a new form of outpatient care, where IOP can be measured by the patients themselves at home using a self-tonometer. This approach should promote the patient's health competence and empowerment within the healthcare system while reducing treatment costs.; METHODS: The SALUS study is a randomized controlled, open non-inferiority trial, alongside an economic analysis, determining whether outpatient monitoring of IOP with self-tonometry is at least as effective as current standard care and would reduce treatment costs. Participants (n=1980) will be recruited by local ophthalmologists in the area of Westphalia-Lippe, Germany, and randomized to receive 7-day outpatient or 24-h inpatient monitoring. Participants in both study arms will also receive 24-h blood pressure monitoring. Furthermore, patient data from both study groups will be collected in an electronic case file (ECF), accessible to practitioners, hospitals, and the study participants. The primary endpoint is the percentage of patients with IOP peaks, defined as levels 30% above the patient-specific target pressure. Data will also be collected during initial and final examinations, and at 3, 6, and 9months after the initial examination.; RESULTS: The study implementation and trial management are represented below.; CONCLUSION: SALUS is a pioneering prospective clinical trial focused on the care of glaucoma patients in Germany. If SALUS is successful, it could improve the healthcare situation and health literacy of the patients through the introduction of various telemedical components. Furthermore, the approach would almost certainly reduce the treatment costs of glaucoma care.; TRIAL REGISTRATION: ClinicalTrials.gov ID: NCT04698876, registration date: 11/25/2020.; DRKS-ID: DRKS00023676, registration date: 11/26/2020. © 2022. The Author(s)
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