Radiation protection and shielding studies are often based on the extensive use of 3D Monte-Carlo neutron and photon transport simulations. ITER organization hence recommends the use of MCNP-5 code ...(version 1.60), in association with the FENDL-2.1 neutron cross section data library, specifically dedicated to fusion applications. The MCNP reference model of the ITER tokamak, the ‘C-lite’, is being continuously developed and improved. This article proposes to develop an alternative model, equivalent to the 'C-lite', but for the Monte-Carlo code TRIPOLI-4®. A benchmark study is defined to test this new model. Since one of the most critical areas for ITER neutronics analysis concerns the assessment of radiation levels and Shutdown Dose Rates (SDDR) behind the Equatorial Port Plugs (EPP), the benchmark is conducted to compare the neutron flux through the EPP. This problem is quite challenging with regard to the complex geometry and considering the important neutron flux attenuation ranging from 1014 down to 108 n•cm-2•s-1. Such code-to-code comparison provides independent validation of the Monte-Carlo simulations, improving the confidence in neutronic results.
The equatorial visible/infrared Wide Angle Viewing System (WAVS) is one of the ITER key diagnostics for machine protection. It has to monitor the Plasma Facing Components (PFCs) by infrared ...thermography and visible imaging. Foreseen to be installed in 4 equatorial port plugs to maximize the coverage of divertor, first wall, heating antennas and upper strike zone, the WAVS is composed of 15 lines of sight and 15 optical systems transferring the light along several meters from the PFCs through the port plug and interspace up to the detectors located in the port cell. After a conceptual design phase led by ITER Organization, the design is being further developed through a Framework Partnership Agreement signed between the European Domestic Agency, Fusion for Energy, and a consortium gathering CEA, CIEMAT (with INTA as third party) and Bertin Technologies company. First the WAVS measurement specifications are presented. Secondly the description of the current design is given both for the in-vessel system and for the ex-vessel one. The on-going neutronic studies are depicted as well as the cameras and data acquisition system foreseen for the back-end of the diagnostic.
•The status of Equatorial Visible/Infra-Red Wide Angle Viewing System is presented.•An assessment of measurement parameters relevant for machine protection has been done.•Remaining uncertainties will ...be clarified during the System Level Design (SLD).•WAVS design is not considered mature enough to launch prototypes of subcomponents.•Mandatory prototypes and qualification tests are already identified.•Next stage (SLD) will enable to do trade-offs and address pending design issues.
The Equatorial Visible/Infra-Red Wide Angle Viewing System (WAVS) is one of the ITER key diagnostics owing to its role in machine investment protection through the monitoring of Plasma Facing Components (PFCs) by Infra-Red thermography and visible imaging. Foreseen to be installed in 4 equatorial port plugs to maximize the coverage of divertor, first wall, heating antennas and upper strike zone, the WAVS will likely be composed of 15 lines of sight and 15 optical systems transferring the light along several meters from the PFCs through the port plug and interspace up to detectors located in the port cell. After a conceptual design phase led by ITER Organization, the design is being further developed through a Framework Partnership Agreement signed between the European Domestic Agency, Fusion for Energy, and a consortium gathering CEA, CIEMAT (with INTA as third party) and Bertin Technologies company. The next design step is the System Level Design (SLD) which will enable to consolidate the WAVS specifications as well as the performance realistically achievable (taking into account ITER and project constraints). The SLD has been preceded by a preparatory phase aiming at clarifying the WAVS functions and identifying critical prototyping.
The outcomes of this preparatory phase are reported in this paper. First a review by the consortium of the WAVS measurement specifications is presented, for the purpose of a clearer separation of measurement parameters mandatory for machine protection (with stringent requirements) from those relevant for machine control and physics studies. Secondly the main features of the diagnostic are summarized, including a description of its current design, a preliminary analysis of its interfaces and a high level functional analysis. Finally the status of the R&D which may be necessary to validate the diagnostic design is presented. On the one hand, this R&D could consist in testing materials and coatings of optical components to characterize their behavior under the harsh environment of ITER. On the other hand R&D activities could concern prototyping and testing of subsystems of the diagnostic which have been identified as critical, such as the first mirrors and their associated devices (shutter and cleaning system) and the differential movement compensation system.
•ITER Continuous External Rogowskis are designed for plasma current measurement.•CER are located in the casing of Toroidal Field Coils and will operate at 4.5K.•The design of the sensors has been ...completed and validated through prototypes.•Detailed assembly procedure inside the toroidal field coil casing has been defined.•The CER has passed all the ITER and F4E design review procedures.
In ITER, an accurate measurement of plasma current, with high reliability, is mandatory as this parameter is used to demonstrate licensing compliance with regulatory limits. For that purpose, several independent measurements based on magnetic diagnostics have been proposed. Rogowski coils are standard inductive sensors for current measurement in many applications. In ITER, three continuous external Rogowski coils are to be installed in the casing of the toroidal field coils. These sensors are remarkable from several points of view: overall length is about 40m, high sensitivity needed, located in the toroidal field coil casing at 4.5K and complex 3D routing with tight bending radius of 50mm. Since 2005 an extensive work has been carried out to develop and analyze several design options complying with ITER specifications. Prototypes of a selected continuous external Rogowski design were built and tested successfully in terms of electrical, thermal, mechanical and vacuum characteristics. Finally a detailed assembly procedure inside the toroidal field coil casing has been defined according to the coil manufacturing and assembly constraints.
The W -for tungsten- environment in steady-state tokamak (WEST) project consists in transforming the French tokamak Tore Supra into an X-point divertor one and aims at testing the ITER technology of ...actively cooled high heat flux tungsten components during ITER-relevant long pulses. In addition to the integration in the vacuum vessel of a lower divertor and an upper one, this metamorphosis has a strong impact on diagnostics initially present in Tore Supra. Indeed, the introduction of a divertor in the upper part of the machine leads to block the lines of sight (LOS) of diagnostics previously installed in the upper ports. Therefore, new diagnostics playing a paramount role for the safe tokamak operation need to be implemented, such as an infrared (IR) thermography diagnostic for the protection of plasma-facing components (PFCs) and heating antennas, and a visible spectroscopy system for the protection of tungsten PFCs. Besides, several existing diagnostics need to be modified to adapt their LOS to the new divertor targets and plasma shape. This paper presents the main issues linked to the integration of diagnostics deriving from the WEST project. First, the changes involved by the upgrade on the set of diagnostics currently implemented in Tore Supra are described. Then, a particular focus is put on the integration of the two new optical systems, namely the IR system and the visible spectroscopy one. These two systems being located within the vacuum vessel, a special care must be paid to their design, to allow them to withstand their harsh environmental conditions. Other new or updated fundamental diagnostics are also briefly presented. Finally, the resulting new implementation of diagnostics envisaged to reach the scientific and technological goals of the WEST project is described.
► An extensive study on the integration of diagnostics in a port plug of ITER has been performed. ► It has shown that the diagnostic performances could not be reached if their number was not ...decreased. ► A design of Diagnostic Shield Modules has been validated through mechanical and thermal analyses. ► These analyses have confirmed that the highest loads are concentrated in the vicinity of the plasma.
Diagnostics in ITER are mandatory to characterize the parameters of plasma and study its interactions with plasma-facing components. Diagnostics components in the vicinity of the plasma are supported by metallic structures called port plugs. At the tokamak mid-plane, these components are installed in port plugs through intermediate structures called drawers. Apart from hosting the diagnostics, the port plugs act as shielding against neutrons and gammas, in order to limit the nuclear loads in crucial components (such as diagnostics and superconducting coils) as well as the dose levels in the controlled zones of the tokamak. The radiation shielding function of the port plugs is ensured through an optimized mixture of heavy metallic materials and water, forming shielding blocks surrounding the diagnostics and called Diagnostic Shield Modules (DSMs). These DSMs constitute the rear part of the drawers (the front part being composed of the Diagnostic First Wall). This paper presents the main results of a study performed in Europe on the integration of a particular diagnostics port plug, the Equatorial Port Plug 1 (EPP1). The paper first provides the results of the EPP1 diagnostics integration analysis. In a second step it focuses on the design of the EPP1 DSMs and summarizes the major results of a thorough set of analyses aiming at studying the DSMs behaviour under different loads, suggesting recommendations to improve their current design.
Diagnostics in International Thermonuclear Experimental Reactor (ITER) are supported by big structures called port plugs, the second main function of which is to ensure a sufficient shielding against ...neutrons and gammas. Regarding the integration of diagnostics in equatorial port plugs, a new approach is under study, which consists in installing the diagnostics in "drawers". This paper describes the recent work which has been performed in Europe on the integration of diagnostics in drawers in the Equatorial Port Plug 1 (EPP1). First, the methodology which has been followed to progress on the integration of the diagnostics in this port plug is described, and the resulting arrangement of diagnostics is shown. Then, a special attention is paid to the integration of the two main diagnostics of EPP1, namely the visible/infrared wide angle viewing system and the radial neutron camera. Finally, the preliminary design of the drawers of EPP1, in particular the shielding modules around the diagnostics, is presented, and the preliminary results of the analyses performed to validate this design are provided.
Heterotopic pancreas, that is the abnormal localization of a well-differentiated pancreatic tissue, is a rare occurrence in pediatric patients. Most lesions are found incidentally; in some ...circumstances, the presence of heterotopic pancreas may cause gastrointestinal symptoms, such as obstructive symptoms or bleeding.
The clinical notes of patients with histological diagnosis of heterotopic pancreas treated at Meyer Children's Hospital between 2009 and 2017 have been retrospectively examined. Four variables have been examined: clinical presentation, age at diagnosis, timing of surgery and localization of the heterotopic pancreas. Patients have been classified accordingly.
Fourteen patients were diagnosed with heterotopic pancreas at a single institution. In half cases, heterotopic pancreas caused symptoms that warranted surgical exploration. Symptomatic patients were significantly older than patients in whom heterotopic pancreas was an incidental finding (mean age 9 years and 5 months vs 2 years and 9 months; p = 0.02). Heterotopic pancreas was more frequently found in patients who underwent urgent surgical procedure than in patients who underwent elective surgery (2.61% vs 0.22%; p < 0.0001). In all cases, foci of heterotopic pancreas were resected.
Heterotopic pancreas is usually discovered in the submucosa of the stomach, duodenum and small bowel. Heterotopic tissue may cause symptoms related to mechanical complications, bleeding from the surrounding intestinal mucosa or, occasionally, to the development of malignancy. Heterotopic tissue is a rare but clinically relevant cause of gastrointestinal symptoms. The presence of heterotopic tissue should be considered in children with gastrointestinal symptoms of unclear origin and surgical resection is advisable.
Background
Allergic rhinitis is a common childhood disease responsible for a major impact on quality of life and healthcare resources. Many hypotheses have been proposed to explain the link between ...allergy and otitis media, although a definitive mechanism has not been identified yet. One of the major critical points is that authors failed in distinguishing among different phenotypes of middle ear inflammation. This review pointed out literature evidence from the laboratory and clinical experience linking allergy to different phenotypes of otitis media in children.
Methods
We performed a systematic review in accordance with the Preferred Reporting Items for Systematic Review and Meta‐Analysis (PRISMA) process. Our search yielded 3010 articles that were finally screened. This resulted in 20 manuscripts of which the full texts were included in a qualitative analysis. We paid particular attention in distinguishing among phenotypes of otitis media.
Results
Clinical evidence and analyses of biomarkers suggested that allergy may be linked to some phenotypes of otitis media and, in particular, to otitis media with effusion (OME) and acute re‐exacerbations in children with middle ear effusion. It was not possible to perform the analysis for allergy and acute and chronic otitis media because of paucity and heterogeneity of data.
Conclusion
Allergy should be considered in the diagnostic workup of children with OME as well as OME should be excluded in children with persistent moderate to severe AR. In these cases, clinicians should evaluate prompt and accurate treatment of allergy in improving outcomes, although futures studies are required to increase evidence supporting that anti‐allergy treatment may be effective in the recovery and outcome of otitis media with effusion.
mPGES-1, a glutathione-dependent membrane protein is involved in the last step of PGE2 production and has been well recognized as a strategic target for the development of anti-inflammatory and ...anti-cancer agents. It has been proven to selectively control the PGE2 levels induced by inflammatory stimuli, with neither affecting PGE2 constitutively produced, nor homeostatic prostanoids, so that its modulation can represent a better strategy to control PGE2 related disorders, compared to the use of the classical anti-inflammatory drugs, endowed with severe side effects. Despite the intensive research on the identification of potent mPGES-1 inhibitors as attractive candidates for drug development, none of the disclosed molecules, except for LY3023705, which recently entered clinical trials, are available for clinical use, therefore the discovery of new effective mPGES-1 inhibitors with increased drug–like properties are urgently needed. Continuing our work aimed at identifying new chemical platforms able to interact with this enzyme, here we describe the discovery of potent mPGES-1 modulators, featuring a 1-fluoro-2,4-dinitro-biphenyl-based scaffold, by processing and docking a small collection of synthetically accessible molecules, built around two main fragments, disclosed in our in silico screening. The top scoring hits obtained have been synthesized and tested, and five of the predicted compounds showed to potently inhibit mPGES-1 enzyme, without affecting COX enzymes activities.
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•New mPGES-1 inhibitors were identified by Fragment Virtual Screening approach.•The active fragment 1 and 2 were developed by means of molecular modeling.•Compounds 1a-c and 1e selectively inhibit mPGES-1 in the low micromolar range.
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