Benchmark between antenna code TOPICA, RAPLICASOL and Petra-M for the ICRH ITER antenna

ITER will be equipped with three plasma heating systems: neutral beam (NB), electron cyclotron (EC), and ion cy-clotron resonance heating (ICRH). The latter consists of two identical ICRH antennas to deliver 20 MW to the plasma (baseline, upgradable to 40 MW). ICRH will play a crucial role in the ignition and sustainment of burning plasmas in ITER. A high fidelity and robust modeling effort to understand the interaction of the IC waves with the scrape-off-layer (SOL) plasma is a very important aspect. Among the main important research topics, we have the assessment of the antenna loading for different plasma scenarios, the role of the lower hybrid resonance in front of the antenna and how to include it in our models, and the RF sheath boundary conditions to evaluate the antenna impurity generation. In this work, we tackle the first of these by reporting on ICRF simulations employing the Petra-M code, which is an electromagnetic simulation tool for modeling RF wave propagation based on MFEM [http://mfem.org] for the ITER ICRH antenna. Moreover, a benchmark between the well tested antenna codes TOPICA, RAPLI-CASOL, which is based on COMSOL [www.comsol.com], and the Petra-M code is also presented. S- and Z-matrices and wave electric field are compared showing an excellent agreement among these codes

TOPLHA: an accurate and efficient numerical tool for analysis and design of LH antennas

This paper presents a self-consistent, integral-equation approach for the analysis of plasma-facing lower hybrid (LH) launchers; the geometry of the waveguide grill structure can be completely arbitrary, including the non-planar mouth of the grill. This work is based on the theoretical approach and code implementation of the TOPICA code, of which it shares the modular structure and constitutes the extension into the LH range. Code results are validated against the literature results and simulations from similar code

Verification/validation and physics model extension in high fidelity 3D RF full wave simulations on Petra-M

This paper reports the recent progress towards a whole-device scale RF actuator simulation. Our approach is to combine progresses made by open source scientific and math software communities for meshing, FEM assembly, and linear solvers to construct an integrated FEM fullwave simulation framework (the Petra-M FEM framework). The goal is to bring in engineering CAD level geometrical detail to our wave simulation capability, and advanced RF wave physics models, such as RF rectified sheath models and non-local hot plasma effects. In Petra-M, the high harmonic fast wave (HHFW) propagation was fully resolved in a 3D NSTX-U torus. In the NSTX-U simulation, the ratio between wavelength to the device size reaches 15, which is in the range required for resolving the ICRF wave fields in ITER. Verification and validation of the RF wave field computed by Petra-M through the international/multi-institutional efforts has been a major research focus, which yields an excellent code benchmark agreement between Petra-M, TOPICA and RAPLCIASOL. The spectral analysis of 3D wave field has been performed to interrogate the wave field behavior, which shows the consistency with the wave theory. RF rectified potential model was incorporated in our wave field solver. We developed a new non-linear iteration algorithm, which allows for using both the thick sheath (asymptotic) model and non-linear sheath impedance models seamlessly. The 3D RF sheath simulation on the WEST ICRF antenna indicates that the sheath potential tends to concentrate near the corner of antenna box, which is consistent with experimental observation of RF induced heat load pattern

Retrospective Study of Regorafenib Versus TAS-102 Efficacy and Safety in Chemorefractory Metastatic Colorectal Cancer (mCRC) Patients: A Multi-institution Real Life Clinical Data

INTRODUCTION: There have been significant developments in colorectal cancer (CRC) research over the last few years, with the introduction of new agents that have been prolonged median overall survival of metastatic colorectal cancer (mCRC). These therapies have improved patient outcomes; however, despite significant progress in strategies for cancer treatment, their use is limited by development of resistant mechanism. Almost 30% of patients with refractory mCRC will remain good candidates for further treatment. Regorafenib and TAS-102 are novel antitumor agents for patients with refractory mCRC. However, it is unclear which patients may derive a survival benefit from these drugs in real-life clinical practice.; METHODS: We performed a retrospective analysis evaluating safety and efficacy of TAS-102 and regorafenib in a cohort of refractory mCRC patients, in 3 different centers between January 1 2018 and May 31 2020, with the aim of assessing the optimal sequence treatment for these 2 drugs.; RESULTS: One hundred and forty mCRC patients were included in the analysis. Of these patients, 64 received regorafenib and 76 received TAS-102 as first treatment. After progression, in the regorafenib 24 (37%) patients switched to secondary treatment with TAS-102, instead, in the TAS-102 group, among 76 patients, 29 (45%) patients switched to secondary treatment with regorafenib. Disease control was achieved in 8 (12.5%) of 64 patients in the regorafenib group and 17 (22.4%) of 76 patients in the TAS-102 group. In terms of efficacy, the PFS and OS were similar in both treatment groups for primary and secondary treatments. AEs reported in this analysis were mostly consistent with the known safety profiles of regorafenib and TAS-102 in previous clinical trials.; CONCLUSION: The present study is the first one to compare the activity of the two agents in a large cohort of chemo-refractory mCRC patients providing more details about the best sequence, to be incorporated in clinical practice. Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved

Characterizations and first plasma operation of the WEST load-resilient actively cooled ICRF launchers

The paper discusses the characterization of the three high power steady-state and load-resilient ICRF launchers of WEST before their installation in the tokamak. These launchers have been characterized and validated in low-power experiments (milliwatt range) as well as in experiments at the nominal RF voltages and currents in the TITAN vacuum chamber (~30 kV and 915 A peak). The successful commissioning of two of the launchers during the WEST C3 campaign at ~1 MW power level is illustrated. Manual and real-time controlled impedance-matching of the launchers are discussed, as well as the validation of their load-resilience. Furthermore, several redundant and complementary protection systems have been validated and are reviewed in the paper

Synthesis and solid-state characterisation of 4-substituted methylidene oxindoles

Background 4-substituted methylidene oxindoles are pharmacologically important. Detailed analysis and comparison of all the interactions present in crystal structures is necessary to understand how these structures arise. The XPac procedure allows comparison of complete crystal structures of related families of compounds to identify assemblies that are mainly the result of close-packing as well as networks of directed interactions. Results Five 4-substituted methylidene oxindoles have been synthesized by the Knoevenagel condensation of oxindole with para-substituted aromatic aldehydes and were characterized in the solid state by x-ray crystallography. Hence, the structures of (3E)-3-(4-Bromobenzylidene)-1,3-dihydro-2H-indol-2-one, 3a, (3E)-3-(4-Chlorobenzylidene)-1,3-dihydro-2H-indol-2-one, 3b, (3E)-3-(4-Methoxybenzylidene)-1,3-dihydro-2H-indol-2-one, 3c, (3E)-3-(4-Methylbenzylidene)-1,3-dihydro-2H-indol-2-one, 3d and (3E)-3-(4-Nitrobenzylidene)-1,3-dihydro-2H-indol-2-one, 3e, were elucidated using single crystal X-ray crystallography. Conclusions A hydrogen bonded dimer molecular assembly or supramolecular construct was identified in all the crystal structures examined along with a further four 1D supramolecular constructs which were common to at least two of the family of structures studied. The 1D supramolecular constructs indicate that once the obvious strong interaction is satisfied to form hydrogen bonded dimer it is the conventionally weaker interactions, such as steric bulk and edge-to-face interactions which compete to influence the final structure formation