The development and application of permanent-magnet EDS based on Halbach structure
With the permanent-magnet EDS (Electro-dynamic Suspension) system as the background, rectilineal PM Halbach structure is introduced. The theory and stability of permanent-magnet EDS system are analyzed which concludes that permanent-magnet EDS system is of greater advantage under high speed condition. Then two present projects based on the the permanent-magnet EDS which aim at actual application, the GA urban maglev train and the Inductrack rocket launch assist system in US, are introduced in details. Adopting double layers PM halbach structure#GA urban maglev train solves the shortage that the levitation-drag ratio is smaller in low speed condition. The Inductrack rocket launch assist system can save fuel and send more payloads. Finally, Permanent EDS research development status home is generalized.
Design, optimization and purity of permanent magnet helical wigglers for free-electron lasers
A helical wiggler field can be produced inside a cylindrical waveguide by properly distributing and orienting an array of permanent magnets within an annular shell surrounding the waveguide. The design and optimization of such wigglers is considered herein, along with assessments of the strength and spectral purity achievable under practical constraints of equally and uniformly magnetized rare-earth cobalt magnets. Starting with the optimum continuum magnetization, a design is derived that differs from Halbach's primarily in that it includes axially directed components of magnetization. A comparison of the two approaches to helical wiggler design is made in terms of the field strength and purity each can achieve under similar constraints. The optimized design is shown to generate stronger and purer helical wiggler fields than Halbach's version for typical parameters. A modified design that uses many small magnets and does not fill the annular space is suggested and evaluated.
Sources of Information on Lymphoma Associated with Anti-Tumour Necrosis Factor Agents
AbstractBackground: Anti-tumour necrosis factor (TNF) agents, through their intense immunoregulatory effect, have been suspected to increase the risk of malignant lymphoma. However, the classical epidemiological approaches conducted over about the last 10 years have not totally succeeded in addressing the question of a causal or artifactual association. Therefore, the analysis of a substantial set of case reports, although usually considered as poorly generalizable to the general population, could be particularly informative. Two main sources of case reports in postmarketing settings are available; publications in medical journals and reports to pharmacovigilance systems.
 Objective: The aim of the study was to compare the characteristics of case reports from both these sources in order to understand whether they provided the same information for the investigation of the causal link between lymphoma and anti-TNF agents.
 Methods: All case reports of malignant lymphoma in patients treated with an anti-TNF agent published in MEDLINE and all reports to the French pharmacovigilance system up to 1 February 2010 were identified. Cases of malignant lymphoma identified in postmarketing surveillance from both sources were compared regarding the following variables: age, sex, anti-TNF agent involved, indication for use, type of lymphoma, prior or concomitant immunosuppressive drugs and time to onset of lymphoma.
 Results: A total of 81 published case reports and 61 cases reported to the French pharmacovigilance system were compared. In published reports, patients were younger (p = 0.03) and more frequently receiving a first anti-TNF treatment (p = 0.03), particularly infliximab (p = 0.03). Conversely, in the pharmacovigilance system reports, a succession of different anti-TNFs (p = 0.03) and adalimumab (p< 0.0001) were more frequently reported. Lymphomas in patients treated with anti-TNF agents for Crohn’s disease were more prevalent in published cases than in pharmacovigilance reports (p< 0.0001), and in particular involved hepatosplenic T-cell lymphoma. Conversely, rheumatoid arthritis was the main indication for anti-TNF agents in pharmacovigilance reports (p = 0.01). Time to onset was markedly shorter in published cases (median 12 months) than in pharmacovigilance reports (median 30 months; p = 0.0001).
 Conclusions: Characteristics of published cases and those reported to the French pharmacovigilance system differed markedly for all characteristics tested, except sex and the use of prior or concomitant immunosuppressive drugs. Published case reports favoured convincing arguments for drug causation whereas cases reported to the pharmacovigilance system were more disparate but could describe more accurately the reality of lymphoma occurrence in this particular population. These results argue for the use of the pharmacovigilance reports when case reports are used to investigate the causal link between lymphoma and anti-TNF agents at the population level. Data from cases notified to the French pharmacovigilance system did not indicate an increased risk of lymphoma during the early phase of anti-TNF treatment. To confirm this hypothesis, a study combining pharmacovigilance reports from several countries, or, if feasible, a cohort study both with a large sample size and a long duration of follow-up would be required.